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Sebastian A, Wyld L, Morgan JL. Examining the variation in consent in general surgery. Ann R Coll Surg Engl 2024; 106:140-149. [PMID: 37218649 PMCID: PMC10830343 DOI: 10.1308/rcsann.2023.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2023] [Indexed: 05/24/2023] Open
Abstract
INTRODUCTION Consent is a fundamental aspect of surgery and expectations around the consent process have changed following the Montgomery vs Lanarkshire Health Board (2015) court ruling. This study aimed to identify trends in litigation pertaining to consent, explore variation in how consent is practised among general surgeons and identify potential causes of this variation. METHODS This mixed-methods study examined temporal variation in litigation rates relating to consent (between 2011 and 2020), using data obtained from National Health Service (NHS) Resolutions. Semi-structured clinician interviews were then conducted to gain qualitative data regarding how general surgeons take consent, their ideologies and their outlook on the recent legal changes. The quantitative component included a questionnaire survey aiming to explore these issues with a larger population to improve the generalisability of the findings. RESULTS NHS Resolutions litigation data showed a significant increase in litigation pertaining to consent following the 2015 health board ruling. The interviews demonstrated considerable variation in how surgeons approach consent. This was corroborated by the survey, which illustrated considerable variation in how consent is documented when different surgeons are presented with the same case vignette. CONCLUSION A clear increase in litigation relating to consent was seen in the post-Montgomery era, which may be due to legal precedent being established and increased awareness of these issues. Findings from this study demonstrate variability in the information patients receive. In some cases, consent practices did not adequately meet current regulations and therefore are susceptible to potential litigation. This study identifies areas for improvement in the practice of consent.
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Affiliation(s)
| | - L Wyld
- University of Sheffield Medical School, UK
| | - JL Morgan
- University of Sheffield Medical School, UK
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2
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Lei Y, Zhang T, Lin YC, Granzier-Nakajima T, Bepete G, Kowalczyk DA, Lin Z, Zhou D, Schranghamer TF, Dodda A, Sebastian A, Chen Y, Liu Y, Pourtois G, Kempa TJ, Schuler B, Edmonds MT, Quek SY, Wurstbauer U, Wu SM, Glavin NR, Das S, Dash SP, Redwing JM, Robinson JA, Terrones M. Graphene and Beyond: Recent Advances in Two-Dimensional Materials Synthesis, Properties, and Devices. ACS Nanosci Au 2022; 2:450-485. [PMID: 36573124 PMCID: PMC9782807 DOI: 10.1021/acsnanoscienceau.2c00017] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 12/30/2022]
Abstract
Since the isolation of graphene in 2004, two-dimensional (2D) materials research has rapidly evolved into an entire subdiscipline in the physical sciences with a wide range of emergent applications. The unique 2D structure offers an open canvas to tailor and functionalize 2D materials through layer number, defects, morphology, moiré pattern, strain, and other control knobs. Through this review, we aim to highlight the most recent discoveries in the following topics: theory-guided synthesis for enhanced control of 2D morphologies, quality, yield, as well as insights toward novel 2D materials; defect engineering to control and understand the role of various defects, including in situ and ex situ methods; and properties and applications that are related to moiré engineering, strain engineering, and artificial intelligence. Finally, we also provide our perspective on the challenges and opportunities in this fascinating field.
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Affiliation(s)
- Yu Lei
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Institute
of Materials Research, Tsinghua Shenzhen
International Graduate School, Shenzhen, Guangdong 518055, China,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tianyi Zhang
- Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yu-Chuan Lin
- Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tomotaroh Granzier-Nakajima
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - George Bepete
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Dorota A. Kowalczyk
- Department
of Solid State Physics, Faculty of Physics and Applied Informatics, University of Lodz, Pomorska 149/153, Lodz 90-236, Poland
| | - Zhong Lin
- Department
of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Da Zhou
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Thomas F. Schranghamer
- Department
of Engineering Science and Mechanics, Pennsylvania
State University, University Park, Pennsylvania 16802, United States
| | - Akhil Dodda
- Department
of Engineering Science and Mechanics, Pennsylvania
State University, University Park, Pennsylvania 16802, United States
| | - Amritanand Sebastian
- Department
of Engineering Science and Mechanics, Pennsylvania
State University, University Park, Pennsylvania 16802, United States
| | - Yifeng Chen
- Department
of Materials Science and Engineering, National
University of Singapore, 9 Engineering Drive, Singapore 117456, Singapore
| | - Yuanyue Liu
- Texas
Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | | | - Thomas J. Kempa
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21287, United States
| | - Bruno Schuler
- nanotech@surfaces
Laboratory, Empa − Swiss Federal
Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
| | - Mark T. Edmonds
- School
of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Su Ying Quek
- Department
of Materials Science and Engineering, National
University of Singapore, 9 Engineering Drive, Singapore 117456, Singapore
| | - Ursula Wurstbauer
- Institute
of Physics, University of Münster, Wilhelm-Klemm-Str. 10, Münster 48149, Germany
| | - Stephen M. Wu
- Department
of Electrical and Computer Engineering & Department of Physics
and Astronomy, University of Rochester, Rochester, New York 14627, United States
| | - Nicholas R. Glavin
- Air
Force
Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, Dayton, Ohio 45433, United States
| | - Saptarshi Das
- Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Engineering Science and Mechanics, Pennsylvania
State University, University Park, Pennsylvania 16802, United States
| | - Saroj Prasad Dash
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, Göteborg SE-412 96, Sweden
| | - Joan M. Redwing
- Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joshua A. Robinson
- Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States,
| | - Mauricio Terrones
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Center
for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Material Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States,Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States,Research
Initiative for Supra-Materials and Global Aqua Innovation Center, Shinshu University, 4-17-1Wakasato, Nagano 380-8553, Japan,
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Subbulakshmi Radhakrishnan S, Chakrabarti S, Sen D, Das M, Schranghamer TF, Sebastian A, Das S. A Sparse and Spike-Timing-Based Adaptive Photoencoder for Augmenting Machine Vision for Spiking Neural Networks. Adv Mater 2022; 34:e2202535. [PMID: 35674268 DOI: 10.1002/adma.202202535] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/31/2022] [Indexed: 06/15/2023]
Abstract
The representation of external stimuli in the form of action potentials or spikes constitutes the basis of energy efficient neural computation that emerging spiking neural networks (SNNs) aspire to imitate. With recent evidence suggesting that information in the brain is more often represented by explicit firing times of the neurons rather than mean firing rates, it is imperative to develop novel hardware that can accelerate sparse and spike-timing-based encoding. Here a medium-scale integrated circuit composed of two cascaded three-stage inverters and one XOR logic gate fabricated using a total of 21 memtransistors based on photosensitive 2D monolayer MoS2 for spike-timing-based encoding of visual information, is introduced. It is shown that different illumination intensities can be encoded into sparse spiking with time-to-first-spike representing the illumination information, that is, higher intensities invoke earlier spikes and vice versa. In addition, non-volatile and analog programmability in the photoencoder is exploited for adaptive photoencoding that allows expedited spiking under scotopic (low-light) and deferred spiking under photopic (bright-light) conditions, respectively. Finally, low energy expenditure of less than 1 µJ by the 2D-memtransistor-based photoencoder highlights the benefits of in-sensor and bioinspired design that can be transformative for the acceleration of SNNs.
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Affiliation(s)
| | - Shakya Chakrabarti
- Electrical Engineering and Computer Science, Penn State University, University Park, PA, 16802, USA
| | - Dipanjan Sen
- Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Mayukh Das
- Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Thomas F Schranghamer
- Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Amritanand Sebastian
- Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Saptarshi Das
- Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
- Electrical Engineering and Computer Science, Penn State University, University Park, PA, 16802, USA
- Materials Science and Engineering, Penn State University, University Park, PA, 16802, USA
- Materials Research Institute, Penn State University, University Park, PA, 16802, USA
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Sebastian A, Pendurthi R, Kozhakhmetov A, Trainor N, Robinson JA, Redwing JM, Das S. Two-dimensional materials-based probabilistic synapses and reconfigurable neurons for measuring inference uncertainty using Bayesian neural networks. Nat Commun 2022; 13:6139. [PMID: 36253370 PMCID: PMC9576759 DOI: 10.1038/s41467-022-33699-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 09/27/2022] [Indexed: 12/24/2022] Open
Abstract
Artificial neural networks have demonstrated superiority over traditional computing architectures in tasks such as pattern classification and learning. However, they do not measure uncertainty in predictions, and hence they can make wrong predictions with high confidence, which can be detrimental for many mission-critical applications. In contrast, Bayesian neural networks (BNNs) naturally include such uncertainty in their model, as the weights are represented by probability distributions (e.g. Gaussian distribution). Here we introduce three-terminal memtransistors based on two-dimensional (2D) materials, which can emulate both probabilistic synapses as well as reconfigurable neurons. The cycle-to-cycle variation in the programming of the 2D memtransistor is exploited to achieve Gaussian random number generator-based synapses, whereas 2D memtransistor based integrated circuits are used to obtain neurons with hyperbolic tangent and sigmoid activation functions. Finally, memtransistor-based synapses and neurons are combined in a crossbar array architecture to realize a BNN accelerator for a data classification task.
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Affiliation(s)
- Amritanand Sebastian
- grid.29857.310000 0001 2097 4281Deparment of Engineering Science and Mechanics, Penn State University, University Park, PA 16802 USA
| | - Rahul Pendurthi
- grid.29857.310000 0001 2097 4281Deparment of Engineering Science and Mechanics, Penn State University, University Park, PA 16802 USA
| | - Azimkhan Kozhakhmetov
- grid.29857.310000 0001 2097 4281Department of Materials Science and Engineering, Penn State University, University Park, PA 16802 USA
| | - Nicholas Trainor
- grid.29857.310000 0001 2097 4281Department of Materials Science and Engineering, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 42812D Crystal Consortium Materials Innovation Platform, Penn State University, University Park, PA 16802 USA
| | - Joshua A. Robinson
- grid.29857.310000 0001 2097 4281Department of Materials Science and Engineering, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Department of Chemistry, Penn State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Department of Physics, Penn State University, University Park, PA USA
| | - Joan M. Redwing
- grid.29857.310000 0001 2097 4281Department of Materials Science and Engineering, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 42812D Crystal Consortium Materials Innovation Platform, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Department of Electrical Engineering and Computer Science, Penn State University, University Park, PA USA
| | - Saptarshi Das
- grid.29857.310000 0001 2097 4281Deparment of Engineering Science and Mechanics, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Department of Materials Science and Engineering, Penn State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Department of Electrical Engineering and Computer Science, Penn State University, University Park, PA USA
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Sebastian A, Tomelleri A, Macchioni P, Klinowski G, Salvarani C, Kayani A, Tariq M, Prieto-Peña D, Conticini E, Khurshid M, Inness S, Jackson J, Van der Geest K, Dasgupta B. POS0818 SOUTHEND PRE-TEST PROBABILITY SCORE AND HALO SCORE AS MARKERS FOR DIAGNOSIS AND MONITORING OF GCA: EARLY RESULTS FROM THE PROSPECTIVE HAS-GCA STUDY. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.4064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BackgroundUltrasound (US) is recommended as the first line imaging test in patients with suspected Giant Cell Arteritis (GCA). Traditionally, the US halo sign has been used for diagnosis. We have recently described a composite Halo Score that allows to quantify vascular inflammation on US. Prospective studies on response and disease monitoring are lacking.ObjectivesTo prospectively assess the role of US in diagnosing and monitoring GCA patients. We report early baseline and 12-month data on our current recruitment in a study that has suffered disruption from the pandemic.MethodsHAS GCA (IRAS#264294) is an ongoing, prospective, multicentre study recruiting from referrals of suspected GCA to fast-track clinics. Based on the Southend GCA clinical pre-test probability score (SPTPS)1, patients were stratified in to low, intermediate and high risk categories2. Temporal and axillary US Halo Scores were calculated from the halo thickness and extent in bilateral temporal arteries, parietal and frontal branches (TAHS) and axillary arteries (AAHS). These scores were summed (TAHS x1 plus; AAHS x3) to generate a Total Halo Score (THS)3.Mann Whitney U test was used to compare baseline features between GCA and controls. Wilcoxon signed rank test was used to evaluate disease features at baseline and at 12 months in GCA patients. Sensitivity (Sn), Specificity (Sp) and ROC curve were calculated, where applicable. P value <0.05 is statistically significantResults202 patients (71 GCA, 131 controls) have been recruited thus far: 23 completed 12-month follow up assessment; 6 were lost to follow up (4 died, 2 withdrew consent due to pandemic). Demographics, clinical features, and US results are shown (Table 1).Table 1.Baseline features of GCA patients and controlsGCA (n=71)Controls (n=131)P-valueAge, median (IQR)75 (70-81)68 (62-76)0.001Female, n (%)38 (54)89 (68)0.05SPTPS category, n (%) Low risk0 (0)59 (45)<0.001 Intermediate risk16 (23)49 (37)0.04 High risk55 (77)23 (18)<0.001Halo score (HS), median (range) Temporal artery HS12 (0-22)2 (0-17)<0.0001 Axillary artery HS12 (0-21)6 (0-18)<0.0001 Total HS21 (2-40)8 (0-29)<0.0001Clinical features, n (%) Temporal headache53 (75)93 (71)0.62 Scalp tenderness36 (51)40 (31)0.006 Jaw claudication38 (54)9 (7)<0.001 PMR symptoms29 (41)35 (27)0.06 Constitutional symptoms42 (59)29 (22)<0.001 Visual disturbance40 (56)58 (44)0.11 Vision loss21 (30)9 (7)<0.001AA, axillary artery; GCA, Giant cell arteritis; TA, Temporal arteryAmong GCA patients, 50 had cranial, 5 large-vessel and 16 mixed phenotypes. Diseases were diagnosed by US and additional tests such as PET CT.Jaw claudication (54%) and constitutional symptoms (59%) were the dominant features in GCA patients. Median age was 75 years in GCA (54% females) and 68 years in controls (68% females). GCA and controls were stratified by SPTPS to Low risk (0% vs 45%; Sn-undefined, Sp-98), Intermediate risk (23% vs 37%; Sn-81, Sp-98) and High risk (77% vs 18%; Sn-98, Sp-91). Optimal SPTPS cut-off point was ≥12 (Sn-89, Sp-76).Median THS was 21 in GCA and 8 in controls. Optimal cut-off Halo Score in diagnosis was TAHS ≥5 (Sn-89, Sp-86), AAHS ≥11 (Sn-55, Sp-75), THS ≥15 (Sn-79%, Sp-86%). Baseline Halo Score and CRP levels showed positive correlation (spearman rank correlation). Among the 23 patients who completed 12-months follow up, median TAHS, AAHS and THS reduced from 12 to 2, 12 to 6 and 21 to 10, respectively (Figure 1).ConclusionAlong with SPTPS, Halo Score successfully discriminates GCA from non GCA mimics and. HS is effective in showing 12-month response. This score may be a useful marker to monitor GCA disease activityReferences[1]Laskou F et al. Clin Exp Rheumatol. 2019[2]Sebastian A et al. RMD Open. 2020[3]Sebastian A et al. BMC Rheumatol. 2020Disclosure of InterestsAlwin Sebastian: None declared, Alessandro Tomelleri: None declared, Pierluigi Macchioni: None declared, Giulia Klinowski: None declared, Carlo Salvarani: None declared, Abdul Kayani: None declared, Mohammad Tariq: None declared, Diana Prieto-Peña: None declared, Edoardo Conticini: None declared, Muhammad Khurshid: None declared, Sue Inness: None declared, Jo Jackson: None declared, Kornelis van der Geest Speakers bureau: Roche, Grant/research support from: Mandema stipend, Bhaskar Dasgupta: None declared
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Sebastian A, Das S, Das S. An Annealing Accelerator for Ising Spin Systems Based on In-Memory Complementary 2D FETs. Adv Mater 2022; 34:e2107076. [PMID: 34761447 DOI: 10.1002/adma.202107076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Metaheuristic algorithms such as simulated annealing (SA) are often implemented for optimization in combinatorial problems, especially for discreet problems. SA employs a stochastic search, where high-energy transitions ("hill-climbing") are allowed with a temperature-dependent probability to escape local optima. Ising spin glass systems have properties such as spin disorder and "frustration" and provide a discreet combinatorial problem with a high number of metastable states and ground-state degeneracy. In this work, subthreshold Boltzmann transport is exploited in complementary 2D field-effect transistors (p-type WSe2 and n-type MoS2 ) integrated with an analog, nonvolatile, and programmable floating-gate memory stack to develop in-memory computing primitives necessary for energy- and area-efficient hardware acceleration of SA for Ising spin systems. Search acceleration of >800× is demonstrated for 4 × 4 ferromagnetic, antiferromagnetic, and spin glass systems using SA compared to an exhaustive search using a brute force trial at miniscule total energy expenditure of ≈120 nJ. The hardware-realistic numerical simulations further highlight the astounding benefits of SA in accelerating the search for larger spin lattices.
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Affiliation(s)
- Amritanand Sebastian
- Deparment of Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Sarbashis Das
- Department of Electrical Engineering, Penn State University, University Park, PA, 16802, USA
| | - Saptarshi Das
- Deparment of Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
- Department of Materials Science and Engineering, Penn State University, University Park, PA, 16802, USA
- Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
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Sebastian A, Darmajaya G, Law N, Sutanto M, Kurniawan A. 353P Treatment outcome of temozolomide in elderly patients with glioblastoma: A systematic review. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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8
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Sebastian A, Tomelleri A, Kayani A, Tariq M, Prieto-Peña D, Inness S, Jackson J, Van der Geest K, Dasgupta B. POS0337 SOUTHEND PRE-TEST PROBABILITY SCORE AND HALO SCORE AS MARKERS FOR DIAGNOSIS AND MONITORING OF GCA: EARLY RESULTS FROM THE PROSPECTIVE HAS-GCA STUDY. Ann Rheum Dis 2021. [DOI: 10.1136/annrheumdis-2021-eular.1038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Background:EULAR recommends doppler ultrasound (US) as the first line imaging in patients with Giant Cell Arteritis (GCA) suspect. Traditionally, US non-compressive halo sign has been used for diagnosis but prospective studies on response and disease monitoring are lackingObjectives:The HAS GCA study has the objective of prospectively assessing role of US in diagnosis, prognosis and monitoring in newly diagnosed GCA. We report early baseline and up to month 3 data on our current recruitment in a study that has suffered disruption from the pandemicMethods:HAS GCA (IRAS#264294) is an ongoing, prospective, multicentre study recruiting from referrals of suspected GCA to fast track clinics. The objective is to recruit 270 patients, including 68 GCA patients. Based on the Southend GCA clinical pre-test probability score (SPTPS)1, patients were stratified in to low, intermediate and high risk categories2. Temporal and axillary US Halo Scores were calculated from the halo thickness and extent in bilateral temporal arteries, parietal and frontal branches and axillary arteries. These individual scores were summed (TA Halo Score x1 plus; AA Halo Score x3) to generate a Total Halo Score (THS)3.Mann Whitney U test and Fisher’s exact test were used to compare baseline features between GCA and controls. Wilcoxon signed rank test was used to evaluate disease features at baseline and at 3 months in GCA patients. Sensitivity (Sn) and Specificity (Sp) were calculated, where applicable. P value <0.05 is statistically significantResults:Ninety-three patients (29 GCA, 64 controls) have been recruited thus far: 18 completed 3-month follow up assessment; 4 were lost to follow up (2 died, 2 withdrew consent due to pandemic). Demographics, clinical features, and US results are shown (Table 1).Table 1.Baseline features of GCA patients and controls.GCA (n=29)Controls (n=64)P-valueAge, median (IQR)75 (71-80)67 (61.25 – 75.0)0.001Female, n (%)15 (42)50 (78)0.01SPTPS category, n (%) Low risk0 (0)31 (48)<0.001 Intermediate risk7 (24)25 (39)0.24 High risk22 (76)8 (13)<0.001Halo score (HS), median (range) Temporal artery HS10 (1-21)1 (0-9)<0.001 Axillary artery HS12 (0-18)6 (0-18)<0.001 Total HS21 (2-38)6 (0-19)<0.001Clinical features, n (%) Temporal headache21 (72)40 (63)0.48 Scalp tenderness17 (59)31 (48)0.38 Jaw claudication19 (66)4 (6)<0.001 PMR symptoms16 (55)6 (9)<0.001 Constitutional symptoms17 (59)18 (28)0.006 Visual disturbance18 (62)38 (59)1 Vision loss7 (24)4 (6)0.03Among GCA patients, 23 had cranial, 2 large-vessel and 4 mixed phenotypes (cranial plus large vessel) disease.Jaw claudication (66%) and polymyalgic symptoms (55%) were the dominant features in GCA patients. Median age 75 years in GCA (42% females) and 67 years in controls (78% females). GCA and controls were stratified by SPTPS to Low risk (0% vs 48%; Sn-undefined, Sp-97), Intermediate risk (24% vs 39%; Sn-100, Sp-100) and High risk (76% vs 13%; Sn-95, Sp-88). Optimal SPTPS cut-off point was ≥12 (Sn-93, Sp-86); ≥10 (Sn-100 & Sp-69).Median THS was 21 in GCA and 6 in controls. Optimal cut-off Halo Score in diagnosis was TAHS ≥5 (Sn-90, Sp-98), AAHS ≥11 (Sn-55, Sp-80), THS ≥18 (Sn-72%, Sp-98%). Among the 18 patients who completed 3-months follow up, median TAHS, AAHS and THS reduced from 10 to 2.5, 12 to 6 and 21 to 10, respectively (Figure 1).Conclusion:Along with SPTPS, Halo Score successfully discriminates GCA from non GCA mimics. HS is effective in showing 3-month response and may be a useful marker to monitor GCA disease activity.References:[1]Laskou F et al. A probability score to aid the diagnosis of suspected giant cell arteritis. Clin Exp Rheumatol. 2019[2]Sebastian A et al. Probability-based algorithm using ultrasound and additional tests for suspected GCA in a fast-track clinic. RMD Open. 2020[3]Sebastian A et al. Halo score (temporal artery, its branches and axillary artery) as a diagnostic, prognostic and disease monitoring tool for Giant Cell Arteritis (GCA). BMC Rheumatol. 2020Disclosure of Interests:Alwin Sebastian: None declared, Alessandro Tomelleri: None declared, Abdul Kayani: None declared, Mohammad Tariq: None declared, Diana Prieto-Peña: None declared, Sue Inness: None declared, Jo Jackson: None declared, Kornelis van der Geest Speakers bureau: Roche, Bhaskar Dasgupta Speakers bureau: Roche, GSK, BMS, Sanofi, Abbie, Grant/research support from: Roche
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9
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Abstract
Spiking neural networks (SNNs) promise to bridge the gap between artificial neural networks (ANNs) and biological neural networks (BNNs) by exploiting biologically plausible neurons that offer faster inference, lower energy expenditure, and event-driven information processing capabilities. However, implementation of SNNs in future neuromorphic hardware requires hardware encoders analogous to the sensory neurons, which convert external/internal stimulus into spike trains based on specific neural algorithm along with inherent stochasticity. Unfortunately, conventional solid-state transducers are inadequate for this purpose necessitating the development of neural encoders to serve the growing need of neuromorphic computing. Here, we demonstrate a biomimetic device based on a dual gated MoS2 field effect transistor (FET) capable of encoding analog signals into stochastic spike trains following various neural encoding algorithms such as rate-based encoding, spike timing-based encoding, and spike count-based encoding. Two important aspects of neural encoding, namely, dynamic range and encoding precision are also captured in our demonstration. Furthermore, the encoding energy was found to be as frugal as ≈1-5 pJ/spike. Finally, we show fast (≈200 timesteps) encoding of the MNIST data set using our biomimetic device followed by more than 91% accurate inference using a trained SNN.
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Affiliation(s)
| | - Amritanand Sebastian
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
| | - Aaryan Oberoi
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
| | - Sarbashis Das
- Department of Electrical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Saptarshi Das
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA.
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA.
- Materials Research Institute, Pennsylvania State University, University Park, PA, USA.
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10
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Feldmann J, Youngblood N, Karpov M, Gehring H, Li X, Stappers M, Le Gallo M, Fu X, Lukashchuk A, Raja AS, Liu J, Wright CD, Sebastian A, Kippenberg TJ, Pernice WHP, Bhaskaran H. Publisher Correction: Parallel convolutional processing using an integrated photonic tensor core. Nature 2021; 591:E13. [PMID: 33623119 DOI: 10.1038/s41586-021-03216-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J Feldmann
- Institute of Physics, University of Münster, Münster, Germany
| | - N Youngblood
- Department of Materials, University of Oxford, Oxford, UK.,Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Karpov
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - H Gehring
- Institute of Physics, University of Münster, Münster, Germany
| | - X Li
- Department of Materials, University of Oxford, Oxford, UK
| | - M Stappers
- Institute of Physics, University of Münster, Münster, Germany
| | - M Le Gallo
- IBM Research Europe, Rüschlikon, Switzerland
| | - X Fu
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - A Lukashchuk
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - A S Raja
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - J Liu
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - C D Wright
- Department of Engineering, University of Exeter, Exeter, UK
| | - A Sebastian
- IBM Research Europe, Rüschlikon, Switzerland.
| | - T J Kippenberg
- Laboratory of Photonics and Quantum Measurements, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
| | - W H P Pernice
- Institute of Physics, University of Münster, Münster, Germany. .,Center for Soft Nanoscience, University of Münster, Münster, Germany.
| | - H Bhaskaran
- Department of Materials, University of Oxford, Oxford, UK.
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11
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Chubarov M, Choudhury TH, Hickey DR, Bachu S, Zhang T, Sebastian A, Bansal A, Zhu H, Trainor N, Das S, Terrones M, Alem N, Redwing JM. Wafer-Scale Epitaxial Growth of Unidirectional WS 2 Monolayers on Sapphire. ACS Nano 2021; 15:2532-2541. [PMID: 33450158 DOI: 10.1021/acsnano.0c06750] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Realization of wafer-scale single-crystal films of transition metal dichalcogenides (TMDs) such as WS2 requires epitaxial growth and coalescence of oriented domains to form a continuous monolayer. The domains must be oriented in the same crystallographic direction on the substrate to inhibit the formation of inversion domain boundaries (IDBs), which are a common feature of layered chalcogenides. Here we demonstrate fully coalesced unidirectional WS2 monolayers on 2 in. diameter c-plane sapphire by metalorganic chemical vapor deposition using a multistep growth process to achieve epitaxial WS2 monolayers with low in-plane rotational twist (0.09°). Transmission electron microscopy analysis reveals that the WS2 monolayers are largely free of IDBs but instead have translational boundaries that arise when WS2 domains with slightly offset lattices merge together. By regulating the monolayer growth rate, the density of translational boundaries and bilayer coverage were significantly reduced. The unidirectional orientation of domains is attributed to the presence of steps on the sapphire surface coupled with growth conditions that promote surface diffusion, lateral domain growth, and coalescence while preserving the aligned domain structure. The transferred WS2 monolayers show neutral and charged exciton emission at 80 K with negligible defect-related luminescence. Back-gated WS2 field effect transistors exhibited an ION/OFF of ∼107 and mobility of 16 cm2/(V s). The results demonstrate the potential of achieving wafer-scale TMD monolayers free of inversion domains with properties approaching those of exfoliated flakes.
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Affiliation(s)
- Mikhail Chubarov
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tanushree H Choudhury
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Danielle Reifsnyder Hickey
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Saiphaneendra Bachu
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tianyi Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Amritanand Sebastian
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Anushka Bansal
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Haoyue Zhu
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nicholas Trainor
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Saptarshi Das
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mauricio Terrones
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nasim Alem
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joan M Redwing
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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12
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Sebastian A, Pendurthi R, Choudhury TH, Redwing JM, Das S. Benchmarking monolayer MoS 2 and WS 2 field-effect transistors. Nat Commun 2021; 12:693. [PMID: 33514710 PMCID: PMC7846590 DOI: 10.1038/s41467-020-20732-w] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 12/17/2020] [Indexed: 11/09/2022] Open
Abstract
Here we benchmark device-to-device variation in field-effect transistors (FETs) based on monolayer MoS2 and WS2 films grown using metal-organic chemical vapor deposition process. Our study involves 230 MoS2 FETs and 160 WS2 FETs with channel lengths ranging from 5 μm down to 100 nm. We use statistical measures to evaluate key FET performance indicators for benchmarking these two-dimensional (2D) transition metal dichalcogenide (TMD) monolayers against existing literature as well as ultra-thin body Si FETs. Our results show consistent performance of 2D FETs across 1 × 1 cm2 chips owing to high quality and uniform growth of these TMDs followed by clean transfer onto device substrates. We are able to demonstrate record high carrier mobility of 33 cm2 V-1 s-1 in WS2 FETs, which is a 1.5X improvement compared to the best reported in the literature. Our experimental demonstrations confirm the technological viability of 2D FETs in future integrated circuits.
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Affiliation(s)
- Amritanand Sebastian
- Department of Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Rahul Pendurthi
- Department of Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA
| | - Tanushree H Choudhury
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Penn State University, University Park, PA, 16802, USA
| | - Joan M Redwing
- 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP), Penn State University, University Park, PA, 16802, USA.,Department of Materials Science and Engineering, Penn State University, University Park, PA, 16802, USA.,Materials Research Institute, Penn State University, University Park, PA, 16802, USA
| | - Saptarshi Das
- Department of Engineering Science and Mechanics, Penn State University, University Park, PA, 16802, USA. .,Department of Materials Science and Engineering, Penn State University, University Park, PA, 16802, USA. .,Materials Research Institute, Penn State University, University Park, PA, 16802, USA.
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13
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Zhang F, Zheng B, Sebastian A, Olson DH, Liu M, Fujisawa K, Pham YTH, Jimenez VO, Kalappattil V, Miao L, Zhang T, Pendurthi R, Lei Y, Elías AL, Wang Y, Alem N, Hopkins PE, Das S, Crespi VH, Phan M, Terrones M. Monolayer Vanadium-Doped Tungsten Disulfide: A Room-Temperature Dilute Magnetic Semiconductor. Adv Sci (Weinh) 2020; 7:2001174. [PMID: 33344114 PMCID: PMC7740087 DOI: 10.1002/advs.202001174] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/09/2020] [Indexed: 05/22/2023]
Abstract
Dilute magnetic semiconductors (DMS), achieved through substitutional doping of spin-polarized transition metals into semiconducting systems, enable experimental modulation of spin dynamics in ways that hold great promise for novel magneto-electric or magneto-optical devices, especially for two-dimensional (2D) systems such as transition metal dichalcogenides that accentuate interactions and activate valley degrees of freedom. Practical applications of 2D magnetism will likely require room-temperature operation, air stability, and (for magnetic semiconductors) the ability to achieve optimal doping levels without dopant aggregation. Here, room-temperature ferromagnetic order obtained in semiconducting vanadium-doped tungsten disulfide monolayers produced by a reliable single-step film sulfidation method across an exceptionally wide range of vanadium concentrations, up to 12 at% with minimal dopant aggregation, is described. These monolayers develop p-type transport as a function of vanadium incorporation and rapidly reach ambipolarity. Ferromagnetism peaks at an intermediate vanadium concentration of ~2 at% and decreases for higher concentrations, which is consistent with quenching due to orbital hybridization at closer vanadium-vanadium spacings, as supported by transmission electron microscopy, magnetometry, and first-principles calculations. Room-temperature 2D-DMS provide a new component to expand the functional scope of van der Waals heterostructures and bring semiconducting magnetic 2D heterostructures into the realm of practical application.
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Affiliation(s)
- Fu Zhang
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Boyang Zheng
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Amritanand Sebastian
- Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - David H. Olson
- Department of Mechanical and Aerospace EngineeringUniversity of VirginiaCharlottesvilleVA22904USA
| | - Mingzu Liu
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Kazunori Fujisawa
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Research Initiative for Supra‐MaterialsShinshu University4‐17‐1 WakasatoNagano380‐8553Japan
| | | | | | | | - Leixin Miao
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Tianyi Zhang
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Rahul Pendurthi
- Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Yu Lei
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Ana Laura Elías
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsApplied Physics and AstronomyBinghamton UniversityBinghamtonNY13902USA
| | - Yuanxi Wang
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- 2D Crystal ConsortiumThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Nasim Alem
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Patrick E. Hopkins
- Department of Mechanical and Aerospace EngineeringUniversity of VirginiaCharlottesvilleVA22904USA
| | - Saptarshi Das
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Vincent H. Crespi
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- 2D Crystal ConsortiumThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Manh‐Huong Phan
- Department of PhysicsUniversity of South FloridaTampaFL33620USA
| | - Mauricio Terrones
- Department of Materials Science and EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for 2‐ Dimensional and Layered MaterialsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of PhysicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of ChemistryThe Pennsylvania State UniversityUniversity ParkPA16802USA
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14
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Sebastian A, Kayani A, Ranasinghe C, Dasgupta B. SAT0249 A PROBABILITY-BASED DIAGNOSTIC ALGORITHM FOR SUSPECTED GCA. Ann Rheum Dis 2020. [DOI: 10.1136/annrheumdis-2020-eular.904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background:Clinical presentation of GCA is protean. It is vital to make a secure diagnosis, exclude mimics urgently and avoid inappropriate steroids to minimise side effects. Fast track GCA clinics (FTC) provide rapid specialist assessment with temporal and axillary US (1). EULAR recommendations support US as first-choice test. A pre-test probability score (PTPS) stratifies patients to low (LC), intermediate (IC) and high-risk (HC) categories.Objectives:To validate a diagnostic GCA algorithm based on stratification by PTPS, with sequential US and additional tests (AT), if necessaryMethods:For the algorithm (Figure) retrospective data was extracted from case records of cases seen in 2019. PTPS overall showed median (Q2) score of 9,75thpercentile (Q3) score 12. Based on this and reported cut-off 9.5 (2) we classified LC as PTPS <9, IC 9-12 and HC >12 (Graph). GCA diagnosis was by modified GiACTA including US (Halo), CRP > 5 mg/L and AT if necessary. The algorithm performance was assessed overall and in individual categories.Results:Of 187 consecutive cases, 13 were excluded for incomplete data (tertiary referrals). In remaining 174, GCA confirmed 33%, mean age 72.4 years, 69% females,45% LC, 35% IC, and 20% HC. 130 (75%) had US whereas 44 did not (41 LC, 3 IC) (Figure)In HC, 25/31 (81%) were US +ve, 19 treated as GCA without AT, 6 with AT (Table 2). Of 6 US -ve 3 had GCA confirmed by AT (PET-CT 2, TAB 1). US in HC showed sensitivity 89%, specificity 75%, accuracy 87%, GCA prevalence 87%, mean CRP 65.52 (SEM+/- 8.67).Table 1.US performance with PTPSCategory(n)USGCA, nNon-GCA, nSensitivity (%)Specificity (%)PPV (%)NPV(%)Prevalence (%)Accuracy(%)HC (31)+24124/27(89)3/4(75)24/25(96)3/6(50)27/31(87)(24 + 3)/31(87)-33IC (65)+30030/30(100)35/35(100)30/30(100)35/35(100)30/65(46)(30 + 35)/65(100)-035LC (78)+010/0 (undefined)77/78(99)0/1(0)77/77(100)0/78(0)(0 + 77)/78(99)-077Total (174)+54254/57(95)115/117(98)54/56(96)115/118(97)57/174(33)(54 + 115)/174(97)-3115Abbreviations: GCA, Giant cell arteritis; NPV, Negative predictive value; PPV, Positive predictive value; US, UltrasoundTable 2.US, AT & confirmed diagnosisCategoryUltrasoundNo of ATType of ATFinal Diagnosis+veNot done-veLC(78)1393871x TAB (-), CTB (-)Fibromyalgia1x TAB (-), MRA (-), MR neck (+)Tongue cancer1x CTA (+)Stroke1x CTCAP (-)IA1x PET (-)PMR1xTAB (-)NA AION1x PET (-)CVAIC(65)30332155x TAB (-), 2x PET (-)Not GCA2x TAB (+), 6x PET (+)GCAHC(31)2506101x PET (-)URTI1x TAB (-)NAAION2x PET (+)1x TAB (+)1x CTA (+)1x MRA (+)GCA1x PET (-)2x CTA (-)1x CTCAP (-)Abbreviations: AT, Additional test; CTA, Computed tomography angiogram; CTB, Computed tomography of brain; CTCAP, Computed tomography of chest, abdomen and pelvis; GCA, Giant cell arteritis; IA, Inflammatory arthritis; MRA, Magnetic resonant angiogram; NA AION, Non arteritic anterior ischemic optic neuritis; PET, Position emission tomography; TAB, Temporal artery biopsy; URTI, Upper respiratory tract infectionIn LC, 38 (49%) were US - ve, of whom 5 had AT. US not done on 39 (50%) for either PTPS very low or urgent alternative diagnosis. 1 went on to AT. 1 was US positive and had GCA excluded with AT. US in LC showed specificity 99%, sensitivity 0/0 (undefined), accuracy 99%, GCA prevalence 0%, mean CRP 21.79 (SEM+/- 3.80)In IC, 30/65 (46%) were US +ve 8 had AT (all GCA confirmed) while on treatment. 32 (49%) US negative where 7 had AT (all GCA excluded). 3 did not have US. Sensitivity, specificity, accuracy of US was all 100%, GCA prevalence 46%, mean CRP 39.05 (SEM+/- 5.04)US test performance overall sensitivity 95%, specificity 98%, accuracy 97%Conclusion:PTPS successfully stratifies GCA, excludes mimics and enhances US performance. The algorithm interprets correctly US findings and choice of AT.References:[1]Patil et al Clin Exp Rheumatol 2015;33(Suppl 89): S103–6.[2]Laskou et al. Clin Exp Rheumatol. 2019 Feb 15Disclosure of Interests:Alwin Sebastian: None declared, Abdul Kayani: None declared, Chavini Ranasinghe: None declared, Bhaskar Dasgupta Grant/research support from: Roche, Consultant of: Roche, Sanofi, GSK, BMS, AbbVie, Speakers bureau: Roche
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15
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Harvestine JN, Gonzalez-Fernandez T, Sebastian A, Hum NR, Genetos DC, Loots GG, Leach JK. Osteogenic preconditioning in perfusion bioreactors improves vascularization and bone formation by human bone marrow aspirates. Sci Adv 2020; 6:eaay2387. [PMID: 32095526 PMCID: PMC7015678 DOI: 10.1126/sciadv.aay2387] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/26/2019] [Indexed: 05/05/2023]
Abstract
Cell-derived extracellular matrix (ECM) provides a niche to promote osteogenic differentiation, cell adhesion, survival, and trophic factor secretion. To determine whether osteogenic preconditioning would improve the bone-forming potential of unfractionated bone marrow aspirate (BMA), we perfused cells on ECM-coated scaffolds to generate naïve and preconditioned constructs, respectively. The composition of cells selected from BMA was distinct on each scaffold. Naïve constructs exhibited robust proangiogenic potential in vitro, while preconditioned scaffolds contained more mesenchymal stem/stromal cells (MSCs) and endothelial cells (ECs) and exhibited an osteogenic phenotype. Upon implantation into an orthotopic calvarial defect, BMA-derived ECs were present in vessels in preconditioned implants, resulting in robust perfusion and greater vessel density over the first 14 days compared to naïve implants. After 10 weeks, human ECs and differentiated MSCs were detected in de novo tissues derived from naïve and preconditioned scaffolds. These results demonstrate that bioreactor-based preconditioning augments the bone-forming potential of BMA.
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Affiliation(s)
- J. N. Harvestine
- Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
| | - T. Gonzalez-Fernandez
- Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
| | - A. Sebastian
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - N. R. Hum
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - D. C. Genetos
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA
| | - G. G. Loots
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - J. K. Leach
- Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
- Department of Orthopaedic Surgery, School of Medicine, UC Davis Health, Sacramento, CA 95817, USA
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17
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Abstract
The recent decline in energy, size and complexity scaling of traditional von Neumann architecture has resurrected considerable interest in brain-inspired computing. Artificial neural networks (ANNs) based on emerging devices, such as memristors, achieve brain-like computing but lack energy-efficiency. Furthermore, slow learning, incremental adaptation, and false convergence are unresolved challenges for ANNs. In this article we, therefore, introduce Gaussian synapses based on heterostructures of atomically thin two-dimensional (2D) layered materials, namely molybdenum disulfide and black phosphorus field effect transistors (FETs), as a class of analog and probabilistic computational primitives for hardware implementation of statistical neural networks. We also demonstrate complete tunability of amplitude, mean and standard deviation of the Gaussian synapse via threshold engineering in dual gated molybdenum disulfide and black phosphorus FETs. Finally, we show simulation results for classification of brainwaves using Gaussian synapse based probabilistic neural networks.
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Affiliation(s)
- Amritanand Sebastian
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Andrew Pannone
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Shiva Subbulakshmi Radhakrishnan
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
- Electrical and Electronics Engineering, Amrita Vishwa Vidyapeetham, Ettimadai, Coimbatore, Tamil Nadu, 641112, India
| | - Saptarshi Das
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
- Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA.
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18
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Sebastian A, Zhang F, Dodda A, May-Rawding D, Liu H, Zhang T, Terrones M, Das S. Electrochemical Polishing of Two-Dimensional Materials. ACS Nano 2019; 13:78-86. [PMID: 30485063 DOI: 10.1021/acsnano.8b08216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional (2D) layered materials demonstrate their exquisite properties such as high temperature superconductivity, superlubricity, charge density wave, piezotronics, flextronics, straintronics, spintronics, valleytronics, and optoelectronics, mostly, at the monolayer limit. Following initial breakthroughs based on micromechanically exfoliated 2D monolayers, significant progress has been made in recent years toward the bottom-up synthesis of large-area monolayer 2D materials such as MoS2 and WS2 using physical vapor deposition and chemical vapor deposition techniques in order to facilitate their transition into commercial technologies. However, the nucleation and subsequent growth of the secondary, tertiary, and greater numbers of vertical layers poses a significant challenge not only toward the realization of uniform monolayers but also toward maintaining their consistent electronic and optoelectronic properties which change abruptly when transitioning from the monolayer to multilayer form. Chemical or physical techniques which can remove the unwanted top layers without compromising the material quality will have tremendous consequences toward the development of atomically flat, large-area, uniform monolayers of 2D materials. Here, we report a simple, elegant, and self-limiting electrochemical polishing technique that can thin down any arbitrary thickness of 2D material, irrespective of whether these are obtained using powder vapor transport or mechanical exfoliation, into their corresponding monolayer form at room temperature within a few seconds without compromising their atomistic integrity. The effectiveness of this electrochemical polishing technique is inherent to 2D transition-metal dichalcogenides owing to the stability of their basal planes, enhanced edge reactivity, and stronger than van der Waals interaction with the substrate. Our study also reveals that 2D monolayers are chemically more robust and corrosion resistant compared to their bulk counterparts in similar oxidative environments, which enables electrochemical polishing of such materials down to a monolayer.
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Affiliation(s)
- Amritanand Sebastian
- Engineering Science and Mechanics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Fu Zhang
- Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Akhil Dodda
- Engineering Science and Mechanics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Dan May-Rawding
- Energy Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - He Liu
- Department of Chemistry , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Tianyi Zhang
- Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Mauricio Terrones
- Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
- Material Research Institute , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
- Department of Chemistry , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
- Department of Physics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Saptarshi Das
- Engineering Science and Mechanics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
- Material Research Institute , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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19
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Nasr JR, Schulman DS, Sebastian A, Horn MW, Das S. Mobility Deception in Nanoscale Transistors: An Untold Contact Story. Adv Mater 2019; 31:e1806020. [PMID: 30430660 DOI: 10.1002/adma.201806020] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/12/2018] [Indexed: 05/19/2023]
Abstract
Mobility is a critical parameter that is routinely used for benchmarking the performance of field-effect transistors (FETs) based on novel nanomaterials. In fact, mobility values are often used to champion nanomaterials since high-performance devices necessitate high mobility values. The current belief is that the contacts can only limit the FET performance and hence the extracted mobility is an underestimation of the true channel mobility. However, here, such misconception is challenged through rigorous experimental effort, backed by numerical simulations, to demonstrate that overestimation of mobility occurs in commonly used geometries and in nanomaterials for which the contact interface, contact doping, and contact geometry play a pivotal role. In particular, dual-gated FETs based on multilayer MoS2 and WSe2 are used as case studies in order to elucidate and differentiate between intrinsic and extrinsic contact effects manifesting in the mobility extraction. The choice of 2D layered transition metal dichalcogenides (TMDCs) as the semiconducting channel is motivated by their potential to replace and/or coexist with Si-based aging FET technologies. However, the results are equally applicable to nanotube- and nanowire-based FETs, oxide semiconductors, and organic-material-based thin-film FETs.
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Affiliation(s)
- Joseph R Nasr
- Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel S Schulman
- Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Amritanand Sebastian
- Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Mark W Horn
- Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Saptarshi Das
- Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
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Kumar A, Sebastian A, Das S, Ringe E. In Situ Optical Tracking of Electroablation in Two-Dimensional Transition-Metal Dichalcogenides. ACS Appl Mater Interfaces 2018; 10:40773-40780. [PMID: 30387342 DOI: 10.1021/acsami.8b14585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are a unique class of 2D materials possessing unique optoelectronic properties when exfoliated into mono- and few-layer sheets. Recently, electroablation (EA) has become of interest as a promising synthesis method for single-layer sheets of TMDs. Here, we introduce spectroelectrochemical micro-extinction spectroscopy (SE-MExS) as a high-throughput technique to study electrochemical thinning of TMDs as it occurs. This approach enables the parallel use of spectroscopy and imaging to nondestructively characterize 2D materials in situ. We unravel optoelectronics of the TMDs by observing changes in optical properties during EA. We find that the EA process for MoS2, WS2, MoSe2, and WSe2 occurs edge first, generating high density of edge sites. Our results show that stable monolayers of MoS2, WS2, and MoSe2 can be synthesized from bulk precursors by the EA process, while conversely, no WSe2 remains postablation.
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Affiliation(s)
| | - Amritanand Sebastian
- Department of Engineering Science and Mechanics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Saptarshi Das
- Department of Engineering Science and Mechanics , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
- Materials Research Institute , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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Gong N, Idé T, Kim S, Boybat I, Sebastian A, Narayanan V, Ando T. Signal and noise extraction from analog memory elements for neuromorphic computing. Nat Commun 2018; 9:2102. [PMID: 29844421 PMCID: PMC5974407 DOI: 10.1038/s41467-018-04485-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/01/2018] [Indexed: 11/09/2022] Open
Abstract
Dense crossbar arrays of non-volatile memory (NVM) can potentially enable massively parallel and highly energy-efficient neuromorphic computing systems. The key requirements for the NVM elements are continuous (analog-like) conductance tuning capability and switching symmetry with acceptable noise levels. However, most NVM devices show non-linear and asymmetric switching behaviors. Such non-linear behaviors render separation of signal and noise extremely difficult with conventional characterization techniques. In this study, we establish a practical methodology based on Gaussian process regression to address this issue. The methodology is agnostic to switching mechanisms and applicable to various NVM devices. We show tradeoff between switching symmetry and signal-to-noise ratio for HfO2-based resistive random access memory. Then, we characterize 1000 phase-change memory devices based on Ge2Sb2Te5 and separate total variability into device-to-device variability and inherent randomness from individual devices. These results highlight the usefulness of our methodology to realize ideal NVM devices for neuromorphic computing.
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Affiliation(s)
- N Gong
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA.,Department of Electrical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, 06511, USA
| | - T Idé
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA
| | - S Kim
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA
| | - I Boybat
- IBM Research-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland.,Ecole Polytechnique Federale de Lausanne (EPFL), Route Cantonale, 1015, Lausanne, Switzerland
| | - A Sebastian
- IBM Research-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland
| | - V Narayanan
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA
| | - T Ando
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA.
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22
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Bachmann TA, Koelmans WW, Jonnalagadda VP, Le Gallo M, Santini CA, Sebastian A, Eleftheriou E, Craciun MF, Wright CD. Memristive effects in oxygenated amorphous carbon nanodevices. Nanotechnology 2018; 29:035201. [PMID: 29235441 DOI: 10.1088/1361-6528/aa9a18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Computing with resistive-switching (memristive) memory devices has shown much recent progress and offers an attractive route to circumvent the von-Neumann bottleneck, i.e. the separation of processing and memory, which limits the performance of conventional computer architectures. Due to their good scalability and nanosecond switching speeds, carbon-based resistive-switching memory devices could play an important role in this respect. However, devices based on elemental carbon, such as tetrahedral amorphous carbon or ta-C, typically suffer from a low cycling endurance. A material that has proven to be capable of combining the advantages of elemental carbon-based memories with simple fabrication methods and good endurance performance for binary memory applications is oxygenated amorphous carbon, or a-CO x . Here, we examine the memristive capabilities of nanoscale a-CO x devices, in particular their ability to provide the multilevel and accumulation properties that underpin computing type applications. We show the successful operation of nanoscale a-CO x memory cells for both the storage of multilevel states (here 3-level) and for the provision of an arithmetic accumulator. We implement a base-16, or hexadecimal, accumulator and show how such a device can carry out hexadecimal arithmetic and simultaneously store the computed result in the self-same a-CO x cell, all using fast (sub-10 ns) and low-energy (sub-pJ) input pulses.
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Affiliation(s)
- T A Bachmann
- Centre for Graphene Science, CEMPS, University of Exeter, Exeter EX4 4QF, United Kingdom
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Schulman DS, Sebastian A, Buzzell D, Huang YT, Arnold AJ, Das S. Facile Electrochemical Synthesis of 2D Monolayers for High-Performance Thin-Film Transistors. ACS Appl Mater Interfaces 2017; 9:44617-44624. [PMID: 29210272 DOI: 10.1021/acsami.7b14711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper, we report high-performance monolayer thin-film transistors (TFTs) based on a variety of two-dimensional layered semiconductors such as MoS2, WS2, and MoSe2 which were obtained from their corresponding bulk counterparts via an anomalous but high-yield and low-cost electrochemical corrosion process, also referred to as electro-ablation (EA), at room temperature. These monolayer TFTs demonstrated current ON-OFF ratios in excess of 107 along with ON currents of 120 μA/μm for MoS2, 40 μA/μm for WS2, and 40 μA/μm for MoSe2 which clearly outperform the existing TFT technologies. We found that these monolayers have larger Schottky barriers for electron injection compared to their multilayer counterparts, which is partially compensated by their superior electrostatics and ultra-thin tunnel barriers. We observed an Anderson type semiconductor-to-metal transition in these monolayers and also discussed possible scattering mechanisms that manifest in the temperature dependence of the electron mobility. Finally, our study suggests superior chemical stability and electronic integrity of monolayers even after being exposed to extreme electro-oxidation and corrosion processes which is promising for the implementation of such TFTs in harsh environment sensing. Overall, the EA process proves to be a facile synthesis route offering higher monolayer yields than mechanical exfoliation and lower cost and complexity than chemical vapor deposition methods.
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Affiliation(s)
| | | | | | - Yu-Ting Huang
- Department of Mechanical Engineering, University of Hong Kong , Pokfulam, Hong Kong
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Huang YT, Dodda A, Schulman DS, Sebastian A, Zhang F, Buzzell D, Terrones M, Feng SP, Das S. Anomalous Corrosion of Bulk Transition Metal Diselenides Leading to Stable Monolayers. ACS Appl Mater Interfaces 2017; 9:39059-39068. [PMID: 29028313 DOI: 10.1021/acsami.7b13107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper we provide insight into an anomalous corrosion process, referred to as electroablation (EA), which converts multilayer flakes of transition metal diselenides like MoSe2 into their corresponding monolayers when micromechanically exfoliated on a conductive electrode and subsequently subjected to a high anodic potential inside a conventional electrochemical cell. Photoluminescence intensity maps and scanning transmission electron microscopy (STEM) images confirmed the single crystalline nature and 2H-hexagonal lattice structure of the remnant monolayer MoSe2 flakes, indicating the superior corrosion stability of the monolayers compared to that of the bulk counterpart. It is noted that the EA technique is a low-cost alternative for high-yield synthesis of single crystalline monolayer MoSe2 at room temperature. We also found that the dynamics of such an electro-oxidation-mediated and self-limiting corrosion process differs significantly for MoSe2 and WSe2. While we were able to engineer the corrosion conditions for the EA process to obtain monolayers of MoSe2, our attempts to obtain monolayers of WSe2 were largely unsuccessful. Finally, we constructed a phenomenological physical chemistry framework to explain such anomalous corrosion processes in transition metal diselenides.
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Affiliation(s)
- Yu-Ting Huang
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Mechanical Engineering, University of Hong Kong , Pokfulam, Hong Kong
| | - Akhil Dodda
- Department of Mechanical Engineering, Amrita Vishwa Vidyapeetham , Amritapuri, Clappana P.O., Kollam, 690525 Kerala, India
| | - Daniel S Schulman
- Department of Materials Science and Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Amritanand Sebastian
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Electronics and Communication Engineering, Amrita Vishwa Vidyapeetham , Amritapuri, Clappana P.O., Kollam, 690525 Kerala, India
| | - Fu Zhang
- Department of Materials Science and Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Drew Buzzell
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Mauricio Terrones
- Department of Materials Science and Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Physics, Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Shien-Ping Feng
- Department of Mechanical Engineering, University of Hong Kong , Pokfulam, Hong Kong
- The University of Hong Kong-Zhejiang Institute of Research and Innovation (HKU-ZIRI) , Hangzhou, Zhejiang 311300, China
| | - Saptarshi Das
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Sebastian A, Thaneeru P, Nair R, Pasupati S. Impact of Patent Foramen Ovale Closure on the Frequency of Migraine: Waikato Hospital Experience. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Sebastian A, Prasad MNV. Iron plaque decreases cadmium accumulation in Oryza sativa L. and serves as a source of iron. Plant Biol (Stuttg) 2016; 18:1008-1015. [PMID: 27439383 DOI: 10.1111/plb.12484] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 07/15/2016] [Indexed: 06/06/2023]
Abstract
Cadmium (Cd) contamination occurs in paddy soils; hence it is necessary to reduce Cd content of rice. Application and mode of action of ferrous sulphate in minimizing Cd in rice was monitored in the present study. Pot culture with Indian rice variety Swarna (MTU 7029) was maintained in Cd-spiked soil containing ferrous sulphates, which is expected to reduce Cd accumulation in rice. Responses in rhizosphere pH, root surface, metal accumulation in plant and molecular physiological processes were monitored. Iron plaque was induced on root surfaces after FeSO4 application and the amount of Fe in plaque reduced with increases in Cd in the soil. Rhizosphere pH decreased during plaque formation and became more acidic due to secretion of organic acids from the roots under Cd treatment. Moreover, iron chelate reductase activity increased with Cd treatment, but in the absence of Cd, activity of this enzyme increased in plaque-induced plants. Cd treatment caused expression of OsYSL18, whereas OsYSL15 was expressed only in roots without iron plaque. Fe content of plants increased during plaque formation, which protected plants from Cd-induced Fe deficiency and metal toxicity. This was corroborated with increased biomass, chlorophyll content and quantum efficiency of photo-synthesis among plaque-induced plants. We conclude that ferrous sulphate-induced iron plaque prevents Cd accumulation and Fe deficiency in rice. Iron released from plaque via organic acid mediated dissolution during Cd stress.
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Affiliation(s)
- A Sebastian
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - M N V Prasad
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India.
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Migalska M, Sebastian A, Konczal M, Kotlík P, Radwan J. De novo transcriptome assembly facilitates characterisation of fast-evolving gene families, MHC class I in the bank vole (Myodes glareolus). Heredity (Edinb) 2016; 118:348-357. [PMID: 27782121 DOI: 10.1038/hdy.2016.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/20/2016] [Indexed: 02/07/2023] Open
Abstract
The major histocompatibility complex (MHC) plays a central role in the adaptive immune response and is the most polymorphic gene family in vertebrates. Although high-throughput sequencing has increasingly been used for genotyping families of co-amplifying MHC genes, its potential to facilitate early steps in the characterisation of MHC variation in nonmodel organism has not been fully explored. In this study we evaluated the usefulness of de novo transcriptome assembly in characterisation of MHC sequence diversity. We found that although de novo transcriptome assembly of MHC I genes does not reconstruct sequences of individual alleles, it does allow the identification of conserved regions for PCR primer design. Using the newly designed primers, we characterised MHC I sequences in the bank vole. Phylogenetic analysis of the partial MHC I coding sequence (2-4 exons) of the bank vole revealed a lack of orthology to MHC I of other Cricetidae, consistent with the high gene turnover of this region. The diversity of expressed alleles was characterised using ultra-deep sequencing of the third exon that codes for the peptide-binding region of the MHC molecule. High allelic diversity was demonstrated, with 72 alleles found in 29 individuals. Interindividual variation in the number of expressed loci was found, with the number of alleles per individual ranging from 5 to 14. Strong signatures of positive selection were found for 8 amino acid sites, most of which are inferred to bind antigens in human MHC, indicating conservation of structure despite rapid sequence evolution.
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Affiliation(s)
- M Migalska
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - A Sebastian
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - M Konczal
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - P Kotlík
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | - J Radwan
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
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Abstract
Psychosocial assessment of transplant candidates is a challenging task. Securing adequate information is made more difficult when patients present with fulminant hepatic failure. When the patient cannot be interviewed and the family is reluctant to provide vital information, a comprehensive pretransplant psychosocial evaluation is virtually impossible. However, even the most difficult cases have the potential for a positive result when a good psychosocial profile of the patient is obtained after transplantation, a team treatment plan is developed and carried out which addresses current and anticipated problems, and the patient obtains mental health treatment.
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Affiliation(s)
- J Carlson
- Nazih Zuhdi Transplantation Institute, Oklahoma City, Okla., USA
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Dziadkowiak E, Sebastian A, Wiland P, Waliszewska-Prosół M, Wieczorek M, Zagrajek M, Ejma M. Endogenous event-related potentials in patients with primary Sjögren's syndrome without central nervous system involvement. Scand J Rheumatol 2015; 44:487-94. [PMID: 26271272 DOI: 10.3109/03009742.2015.1032345] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Endogenous cognitive event-related potentials (CERPs) reflect higher-level processing of sensory information and can be used to evaluate cognitive functions. The aim of this paper was to determine whether there are any abnormalities in the electrophysiological parameters of CERPs in patients with primary Sjögren's syndrome (pSS) but without symptoms of central nervous system (CNS) involvement or mental disorder. The analysis of CERP parameters was then correlated with the clinical status of the patients and with some of the immunological parameters in the patient group. METHOD Thirty consecutive patients with pSS (29 females, one male) were included in the study. All the patients underwent CERP examination. RESULTS There was a significant prolongation of the latency of P300 and N200 potentials in patients with pSS. Abnormalities in electrophysiological parameters of CERPs correlated with the duration of the disease, salivary gland abnormalities, and elevated erythrocyte sedimentation rate (ESR) values. Patients with coexisting chronic fatigue syndrome (CFS) had larger P300 amplitudes. There were no statistically significant changes in the electrophysiological parameters of CERPs in patients with pSS dependent on the presence of peripheral nervous system (PNS) lesions, skin changes, arthritis, abnormalities in white blood cells and the immune system or the levels of blood lipids. CONCLUSIONS The results of the study suggest the presence of a minor cognitive dysfunction in patients with pSS without symptoms of CNS involvement or mental disorder. Cognitive dysfunction correlated with the disease duration time and the severity of inflammatory changes (salivary gland abnormalities and inflammatory markers in the blood). Further and larger longitudinal studies are necessary for confirmation of this correlation.
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Affiliation(s)
- E Dziadkowiak
- a Department of Neurology , Wrocław Medical University , Poland
| | - A Sebastian
- b Department of Rheumatology , Wrocław Medical University , Poland
| | - P Wiland
- b Department of Rheumatology , Wrocław Medical University , Poland
| | | | - M Wieczorek
- c Department of Geography and Regional Development , University of Wrocław , Poland
| | - M Zagrajek
- a Department of Neurology , Wrocław Medical University , Poland
| | - M Ejma
- a Department of Neurology , Wrocław Medical University , Poland
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Sebastian A, Wiland P. AB0540 Diversity of Clinical Manifestations of Primary SjÖgren's Syndrome. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Tabatabai LS, Cummings SR, Tylavsky FA, Bauer DC, Cauley JA, Kritchevsky SB, Newman A, Simonsick EM, Harris TB, Sebastian A, Sellmeyer DE. Arterialized venous bicarbonate is associated with lower bone mineral density and an increased rate of bone loss in older men and women. J Clin Endocrinol Metab 2015; 100:1343-9. [PMID: 25642590 PMCID: PMC4399281 DOI: 10.1210/jc.2014-4166] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Higher dietary net acid loads have been associated with increased bone resorption, reduced bone mineral density (BMD), and increased fracture risk. OBJECTIVE The objective was to compare bicarbonate (HCO3) measured in arterialized venous blood samples to skeletal outcomes. DESIGN Arterialized venous samples collected from participants in the Health, Aging and Body Composition (Health ABC) Study were compared to BMD and rate of bone loss. SETTING The setting was a community-based observational cohort. PARTICIPANTS A total of 2287 men and women age 74 ± 3 years participated. INTERVENTION Arterialized venous blood was obtained at the year 3 study visit and analyzed for pH and pCO2. HCO3 was determined using the Henderson-Hasselbalch equation. MAIN OUTCOME MEASURE BMD was measured at the hip by dual-energy x-ray absorptiometry at the year 1 (baseline) and year 3 study visits. RESULTS Plasma HCO3 was positively associated with BMD at both year 1 (P = .001) and year 3 (P = .001) in models adjusted for age, race, sex, clinic site, smoking, weight, and estimated glomerular filtration rate. Plasma HCO3 was inversely associated with rate of bone loss at the total hip over the 2.1 ± 0.3 (mean ± SD) years between the two bone density measurements (P < .001). Across quartiles of plasma HCO3, the rate of change in BMD over the 2.1 years ranged from a loss of 0.72%/y in the lowest quartile to a gain of 0.15%/y in the highest quartile of HCO3. CONCLUSIONS Arterialized plasma HCO3 was associated positively with cross-sectional BMD and inversely with the rate of bone loss, implying that systemic acid-base status is an important determinant of skeletal health during aging. Ongoing bone loss was linearly related to arterialized HCO3, even after adjustment for age and renal function. Further research in this area may have major public health implications because reducing dietary net acid load is possible through dietary intervention or through supplementation with alkaline potassium compounds.
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Affiliation(s)
- L S Tabatabai
- Division of Endocrinology (L.S.T., D.E.S.), Johns Hopkins Hospital, Johns Hopkins School of Medicine, Baltimore, Maryland 21224; California Pacific Medical Center Research Institute (S.R.C.), San Francisco, California 94118; Department of Preventive Medicine (F.A.T.), University of Tennessee Health Science Center, Memphis, Tennessee 38163; Department of Medicine (D.C.B., A.S.), School of Medicine, University of California, San Francisco, San Francisco, California 94143; Department of Epidemiology (J.A.C., A.N.), Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260; Department of Internal Medicine (S.B.K.), Wake Forest School of Medicine, Winston-Salem, North Carolina 27157; Translational Gerontology Branch (E.M.S.), National Institute on Aging, Baltimore, Maryland 21224; and Laboratory of Epidemiology and Population Science (T.B.H.), National Institute on Aging, Bethesda, Maryland 20892
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Görtz P, Sebastian A, Dietrich S. Assessment-based Home Treatment for People with Schizophrenia Spectrum Disorder. Eur Psychiatry 2015. [DOI: 10.1016/s0924-9338(15)32034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kowalczyk E, Waliszewska-Prosol M, Pokryszko-Dragan A, Nowakowska-Kotas M, Sebastian A, Ejma M. P485: Event-related potentials in patients with primary Sjögren’s syndrome. Clin Neurophysiol 2014. [DOI: 10.1016/s1388-2457(14)50584-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Monova D, Monov S, Todorov T, Soderberg D, Kurz T, Weiner M, Eriksson P, Segelmark M, Jakuszko K, Sebastian A, Bednarz Z, Krajewska M, Wiland P, Madziarska K, Weyde W, Klinger M, Naidoo J, Wearne N, Jones E, Swanepoel C, Rayner B, Okpechi I, Endo N, Tsuboi N, Furuhashi K, Matsuo S, Maruyama S, Clerte M, Levi C, Touzot M, Fakhouri F, Monge C, Lebas C, Abboud I, Huart A, Durieux P, Charlin E, Thervet E, Karras A, Smykal-Jankowiak K, Niemir ZI, Polcyn-Adamczak M, Whatmough S, Sweeney N, Fernandez S, Hussain M, Dhaygude A, Jakuszko K, Bednarz Z, Sebastian A, Krajewska M, Gniewek K, Wiland P, Weyde W, Klinger M, Manenti L, Urban ML, Vaglio A, Gintoli E, Galletti M, Buzio C, Monova D, Monov S, Argirova T, Wong I, Ibrahim FH, Goh BL, Lim TS, Chan MW, Hiramtasu R, Ubara Y, Hoshino J, Takaichi K, Ghafoor V, Hussain M, Dhaygude A, Whatmough S, Fernandez S, Sweeney N, Hussain M, Dhaygude A, Sahay M, Soma J, Nakaya I, Sasaki N, Yoshikawa K, Sato H, Kaminskyy V, ZAbi Ska M, Krajewska M, Ko Cielska-Kasprzak K, Jakuszko K, Klinger M, Niemir Z, Wozniczka K, Swierzko A, Cedzynski M, Polcyn-Adamczak M, Sokolowska A, Szala A, Arjunan A, Mikhail A, Shrivastava R, Parker C, Aithal S, Gursu M, Ozari M, Yucetas E, Sumnu A, Doner B, Cebeci E, Ozkan O, Aktuglu MB, Karaali Z, Koldas M, Ozturk S, Marco H, Picazo M, Da Silva I, Gonzalez A, Arce Y, Gracia S, Corica M, Llobet J, Diaz M, Ballarin J, Schonermarck U, Hagele H, Baumgartner A, Fischereder M, Muller S, Oliveira CBL, Oliveira ASA, Carvalho CJB, Pessoa CTBC, Sette LHBC, Fernandes GV, Cavalcante MAGM, Valente LM, Wan Q, Hu H, He Y, Li T, Aazair N, Houmaid Z, Rhair A, Bennani N, Demin A, Petrova O, Kotova O, Demina L, Roccatello D, Sciascia S, Rossi D, Naretto C, Baldovino S, Alpa M, Salussola I, Modena V, Zakharova EV, Vinogradova OV, Stolyarevich ES, Yap DYH, Chan TM, Thanaraj V, Dhaygude A, Ponnusamy A, Pillai S, Argentiero L, Schena A, Rossini M, Manno C, Castellano G, Martino M, Mitrotti A, Giliberti M, Digiorgio C, Di Palma AM, Battaglia M, Ditonno P, Grandaliano G, Gesualdo L, Oliveira CBL, Carvalho CJB, Oliveira ASA, Pessoa CTBC, Sette LHBC, Fernandes GV, Cavalcante MAGM, Valente LM, Neprintseva N, Tchebotareva N, Bobkova I, Kozlovskaya L, Rabrenovi V, Kova Evi Z, Jovanovi D, Rabrenovi M, Anti S, Ignjatovi L, Petrovi M, Longhi S, Del Vecchio L, Vigano S, Casartelli D, Bigi MC, Corti M, Limardo M, Tentori F, Pontoriero G, Zeraati AA, Shariati Sarabi Z, Davoudabadi Farahani A, Mirfeizi Z, Bae E. PRIMARY AND SECONDARY GLOMERULONEPHRITIDES 2. Nephrol Dial Transplant 2014. [DOI: 10.1093/ndt/gfu170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Frassetto LA, Shi L, Schloetter M, Sebastian A, Remer T. Established dietary estimates of net acid production do not predict measured net acid excretion in patients with Type 2 diabetes on Paleolithic-Hunter-Gatherer-type diets. Eur J Clin Nutr 2013; 67:899-903. [PMID: 23859996 DOI: 10.1038/ejcn.2013.124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 05/22/2013] [Accepted: 06/03/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES Formulas developed to estimate diet-dependent net acid excretion (NAE) generally agree with measured values for typical Western diets. Whether they can also appropriately predict NAE for 'Paleolithic-type' (Paleo) diets-which contain very high amounts of fruits and vegetables (F&V) and concurrent high amounts of protein is unknown. Here, we compare measured NAEs with established NAE estimates in subjects with Type 2 diabetes (T2D). SUBJECTS/METHODS Thirteen subjects with well-controlled T2D were randomized to either a Paleo or American Diabetes Association (ADA) diet for 14 days. Twenty-four hour urine collections were performed at baseline and end of the diet period, and analyzed for titratable acid, bicarbonate and ammonium to calculate measured NAE. Three formulas for estimating NAE from dietary intake were used; two (NAE_diet R or L) that include dietary mineral intake and sulfate- and organic acid (OA) production, and one that is empirically derived (NAE_diet F) only considering potassium and protein intake. RESULTS Measured NAE on the Paleo diet was significantly lower than on the ADA-diet (+31±22 vs 112±52 mEq/day, P=0.002). Although all formula estimates showed similar and reasonable correlations (r=0.52-0.76) with measured NAE, each one underestimated measured values. The formula with the best correlation did not contain an estimate of dietary OA production. CONCLUSIONS Paleo-diets are lower in NAE than typical Western diets. However, commonly used formulas clearly underestimate NAE, especially for diets with very high F&V (as the Paleo diet), and in subjects with T2D. This may be due to an inappropriate estimation of proton loads stemming from OAs, underlining the necessity for improved measures of OA-related proton sources.
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Affiliation(s)
- L A Frassetto
- University of California San Francisco, San Francisco, CA, USA.
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Lech M, Lorenz G, Kulkarni O, Gunthner R, Susanti H, Anders HJ, Kulkarni O, Mulay S, Darisipudi M, Kumar S, LeMaoult J, Carosella ED, Anders HJ, Xu XY, Zheng M, Lv LL, Liu BC, Jakuszko K, Krajewska M, Koscielska-Kasprzak K, Myszka M, Sebastian A, Grzegorczyk K, Augustyniak-Bartosik H, Wiland P, Klinger M, Biesenbach P, Derfler K, Smolen J, Stummvoll G. Lupus nephritis. Nephrol Dial Transplant 2013. [DOI: 10.1093/ndt/gft165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Tüscher O, Schmüser L, Sebastian A, Lieb K, Feige B. Elektrophysiologische Phänotypen der motorischen Impulskontrolle. KLIN NEUROPHYSIOL 2013. [DOI: 10.1055/s-0033-1337217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Sebastian A, Pohl M, Klöppel S, Feige B, Lange T, Stahl C, Voss A, Klauer K, Lieb K, Tüscher O. Disentangling common and specific neural subprocesses of response inhibition. Neuroimage 2013; 64:601-15. [DOI: 10.1016/j.neuroimage.2012.09.020] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 08/30/2012] [Accepted: 09/04/2012] [Indexed: 11/26/2022] Open
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Frassetto L, Sebastian A. How metabolic acidosis and oxidative stress alone and interacting may increase the risk of fracture in diabetic subjects. Med Hypotheses 2012; 79:189-92. [DOI: 10.1016/j.mehy.2012.04.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/20/2012] [Indexed: 01/11/2023]
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Laborda A, Lozano J, Caballero H, Serrano C, Sebastian A, Lopera J, de Gregorio M. Abstract No. 257: Metallic stents for tracheobronchial pathology treatment. J Vasc Interv Radiol 2012. [DOI: 10.1016/j.jvir.2011.12.309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Adlakha A, Rupta R, Sebastian A, Tait P, Jackson J, Ind P. P190 Long-term outcome of bronchial artery embolisation (BAE) for massive haemoptysis. Thorax 2011. [DOI: 10.1136/thoraxjnl-2011-201054c.190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Koelmans WW, Sebastian A, Abelmann L, Despont M, Pozidis H. Force modulation for enhanced nanoscale electrical sensing. Nanotechnology 2011; 22:355706. [PMID: 21821873 DOI: 10.1088/0957-4484/22/35/355706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Scanning probe microscopy employing conductive probes is a powerful tool for the investigation and modification of electrical properties at the nanoscale. Application areas include semiconductor metrology, probe-based data storage and materials research. Conductive probes can also be used to emulate nanoscale electrical contacts. However, unreliable electrical contact and tip wear have severely hampered the widespread usage of conductive probes for these applications. In this paper we introduce a force modulation technique for enhanced nanoscale electrical sensing using conductive probes. This technique results in lower friction, reduced tip wear and enhanced electrical contact quality. Experimental results using phase-change material stacks and platinum silicide conductive probes clearly demonstrate the efficacy of the proposed technique. Furthermore, conductive-mode imaging experiments on specially prepared platinum/carbon samples are presented to demonstrate the widespread applicability of this technique.
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Affiliation(s)
- W W Koelmans
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
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Quenzer H, Drechsler U, Sebastian A, Marauska S, Wagner B, Despont M. Fabrication of conducting AFM cantilevers with AlN-based piezoelectric actuators. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.proeng.2011.12.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Guiteau JJ, Cotton RT, Washburn WK, Harper A, O'Mahony CA, Sebastian A, Cheng S, Klintmalm G, Ghobrial M, Halff G, Mieles L, Goss J. An early regional experience with expansion of Milan Criteria for liver transplant recipients. Am J Transplant 2010; 10:2092-8. [PMID: 20883543 DOI: 10.1111/j.1600-6143.2010.03222.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Milan Criteria (MC) showed that orthotopic liver transplantation (OLT) was an effective treatment for patients with nonresectable, nonmetastatic HCC. There is growing evidence that expanding the MC does not adversely affect patient or allograft survival following OLT. The adult OLT programs in UNOS Region 4 reached an agreement allowing lesions outside MC (one lesion <6 cm, ≤3 lesions, none >5 cm and total diameter <9 cm-[R4 T3]) to receive the same exception points as MC lesions. Kaplan-Meier curves and log-rank tests were used to compare survival data. Chi-squared and Mann-Whitney U tests were used to compare patient data. A p-value of <0.05 was considered significant. All statistical analyses were performed on SPSS 15 (SPSS, Chicago, IL). Four hundred and forty-five patients were transplanted for HCC (363-MC and 82-R4 T3). Patient demographics were found to be similar between the two groups. Three year patient, allograft and recurrence free survival between MC and R4 T3 were found to be 72.9% and 77.1%, 71% and 70.2% and 90.5% and 86.9%, respectively (all p > 0.05). We report the first regionalized multicenter, prospective study showing benefit of OLT in patients exceeding MC based on preoperative imaging.
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Affiliation(s)
- J J Guiteau
- Division of Abdominal Transplantation and Hepatobiliary Surgery, Baylor College of Medicine, Houston, TX, USA
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Tuescher O, Bader K, Kamphausen S, Maier S, Sebastian A, Jacob G, van Elst LT, Lieb K. Emotional Modulation of Impulse-control in Borderline Personality Disorder. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)71995-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC, Sebastian A. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr 2009; 63:947-55. [PMID: 19209185 DOI: 10.1038/ejcn.2009.4] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The contemporary American diet figures centrally in the pathogenesis of numerous chronic diseases-'diseases of civilization'. We investigated in humans whether a diet similar to that consumed by our preagricultural hunter-gatherer ancestors (that is, a paleolithic type diet) confers health benefits. METHODS We performed an outpatient, metabolically controlled study, in nine nonobese sedentary healthy volunteers, ensuring no weight loss by daily weight. We compared the findings when the participants consumed their usual diet with those when they consumed a paleolithic type diet. The participants consumed their usual diet for 3 days, three ramp-up diets of increasing potassium and fiber for 7 days, then a paleolithic type diet comprising lean meat, fruits, vegetables and nuts, and excluding nonpaleolithic type foods, such as cereal grains, dairy or legumes, for 10 days. Outcomes included arterial blood pressure (BP); 24-h urine sodium and potassium excretion; plasma glucose and insulin areas under the curve (AUC) during a 2 h oral glucose tolerance test (OGTT); insulin sensitivity; plasma lipid concentrations; and brachial artery reactivity in response to ischemia. RESULTS Compared with the baseline (usual) diet, we observed (a) significant reductions in BP associated with improved arterial distensibility (-3.1+/-2.9, P=0.01 and +0.19+/-0.23, P=0.05);(b) significant reduction in plasma insulin vs time AUC, during the OGTT (P=0.006); and (c) large significant reductions in total cholesterol, low-density lipoproteins (LDL) and triglycerides (-0.8+/-0.6 (P=0.007), -0.7+/-0.5 (P=0.003) and -0.3+/-0.3 (P=0.01) mmol/l respectively). In all these measured variables, either eight or all nine participants had identical directional responses when switched to paleolithic type diet, that is, near consistently improved status of circulatory, carbohydrate and lipid metabolism/physiology. CONCLUSIONS Even short-term consumption of a paleolithic type diet improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans.
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Affiliation(s)
- L A Frassetto
- Department of Medicine, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA.
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Sebastian A, Kohli V, Huang Y, Li SF, Yong Y, Jabbour N, Sigle G, Gurakar A, Wright H. NOVEL CLINICAL MONITORING OF CELL MEDIATED IMMUNITY (CMI) USING IMMUNKNOW(r) IN LIVER TRANSPLANT RECIPIENTS PROVIDES OPTIMAL IMMUNE SUPPRESSION AND IMPROVED OUTCOMES. Transplantation 2008. [DOI: 10.1097/01.tp.0000332055.98495.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Rizvi S, Camci C, Yong Y, Parker G, Shrago S, Stokes K, Wright H, Sebastian A, Gurakar A. Is post-Lipiodol CT better than i.v. contrast CT scan for early detection of HCC? A single liver transplant center experience. Transplant Proc 2007; 38:2993-5. [PMID: 17112883 DOI: 10.1016/j.transproceed.2006.08.125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Indexed: 11/29/2022]
Abstract
Hepatocellular carcinoma is a highly vascular neoplasm usually arising from a cirrhotic liver. Delayed, noncontrast, computed tomography (CT) imaging after 7 to 14 days reveals an oil-based contrast agent to be concentrated in the tumor but not in normal hepatic parenchyma. The aim of this study was to retrospectively correlate the post Lipiodol CT scan findings with respect to tumor size in the explanted liver. We retrospectively reviewed adult patients who had undergone orthotopic liver transplantation between November 1995 and December 2004 and also had an hepatic arteriogram with Lipiodol injection as part of their pretransplant workup. We calculated sensitivity, specificity, false-negativity, false-positivity, and accuracy of the test, as well as positive and negative predictive values. Lipiodol CT exam had sensitivity of 1.0; specificity of 0.6 with a calculated positive predictive value of 0.89 and a negative predictive value of 1.0. Overall accuracy of Lipiodol CT scan test was found to be 0.91, which was superior to an intravenous contrast CT alone. In conclusion, because of the higher sensitivity and accuracy values, hepatic arterial Lipiodol injection can be considered during the pretransplantation workup of high-risk cirrhotic patients, since the current model for End-stage Liver Disease scoring system for hepatocellular carcinoma is built on the ultimate bulk of the tumor. Further multicenter, controlled, large-volume prospective studies are warranted to verify this observation.
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Affiliation(s)
- S Rizvi
- Section of Gastroenterology, Oklahoma University Health Sciences Center, Oklahoma City, Oklahoma, USA
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Daigeler A, Lehnhardt M, Sebastian A, Belyaev O, Steinstraesser L, Steinau HU, Kuhnen C. Metachronous bilateral soft tissue sarcoma of the extremities. Langenbecks Arch Surg 2007; 393:207-12. [PMID: 17242894 DOI: 10.1007/s00423-006-0145-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Accepted: 12/21/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND AIMS Synchronous and heterochronous multiple soft tissue sarcoma of the extremities is very rare. Out of 1,201 of our patients, 4 patients presented with symmetrical bilateral soft tissue sarcoma of the extremities. The aim of this study was to identify possible reasons for this unusual manifestation of sarcomas. MATERIALS AND METHODS The patients' data was acquired by review of the patients' charts and follow-up information was gathered by phone calls to the patients or their relatives and their general practitioners. RESULTS All tumours were located at the extremities and were diagnosed as leiomyosarcoma in two patients, malignant fibrous histiocytoma and clear cell sarcoma in one patient each. No other individual or family history of cumulation of neoplasms was known in the patients. The median interval between the diagnoses was 3 1/2 years (range: 4 months to 9 1/2 years). In two patients a second primary sarcoma of the same entity was considered the most likely diagnosis, whereas in one patient a contralateral lymph node metastasis and in one other patient an atypical soft tissue metastasis had to be taken into account. A positive family history with a father with malignant fibrous histiocytoma may indicate a hereditary predisposition in one patient. Aside from irradiation effects, exposition to other carcinogenic agents or genetic predisposition, the reasons for the clustering of soft tissue sarcoma in one same patient remain still unclear. Only one patient, although suffering from disseminated metastatic disease was living at follow-up time, the other three patients had already died. CONCLUSION The interpretation of the bilateral manifestation of soft tissue sarcoma remains open, but predicts an unfavourable outcome.
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Affiliation(s)
- A Daigeler
- Department of Plastic Surgery, Burn Center, Hand Center, Sarcoma Reference Center, BG-University-Hospital Bergmannsheil, Ruhr-University, Buerkle-de-la-Camp-Platz 1, 44789, Bochum, Germany.
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Akdogan M, Camci C, Gurakar A, Gilcher R, Alamian S, Wright H, Nour B, Sebastian A. The effect of total plasma exchange on fulminant hepatic failure. J Clin Apher 2006; 21:96-9. [PMID: 16142721 DOI: 10.1002/jca.20064] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Total plasma exchange (TPE) corrects coagulopathy in patients with liver disease and removes hepatotoxins/cytokines. This improvement is transient but can be used as a bridge until an organ is identified for liver transplantation (LTx) or the liver itself regenerates. Our aim was to retrospectively assess the efficacy of TPE in fulminant hepatic failure (FHF) and its impact on liver function tests. Between 1995-2001, 39 patients with FHF who had undergone TPE were reviewed. FHF was defined according to the O'Grady criteria based on the duration of encephalopathy as well as jaundice. TPE was performed using the Cobe Spectra TPE (Gambro) in Liver Intensive Care Unit, continued on a daily basis, until either adequate clinical response was achieved, the patient expired, or transplantation occurred. INR, PTT, Fibrinogen, ALT, AST, GGT, BUN, Ammonia, and Total Bilirubin were analyzed before and after TPE. Student's t-test and chi-square test and ANOVA were used for statistical analysis. Thirty-nine patients with FHF (31 females, 8 males with mean age of 32.3, range: 7-64) underwent TPE. Coagulopathy, hyperbilirubinemia, hyperammonemia were significantly improved (P < 0.05). Twenty-one patients survived (54%), 12 required LTx, and 18 patients (including one after LTx) expired. TPE was found to be significantly effective for correction of coagulopathy and improvement of liver tests. This intervention can be considered for temporary liver support until recovery or liver transplantation.
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Affiliation(s)
- M Akdogan
- Nazih Zuhdi Transplant Institute, INTEGRIS Baptist Medical Center, Oklahoma City, OK 73120, USA
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