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Nasiłowska J, Kocot A, Osuchowska PN, Sokołowska B. High-Pressure-Induced Sublethal Injuries of Food Pathogens-Microscopic Assessment. Foods 2021; 10:2940. [PMID: 34945491 DOI: 10.3390/foods10122940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/17/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022] Open
Abstract
High Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they may proliferate in food during storage. This study was undertaken to characterize the extent of sublethal injuries induced by HHP (300-500 MPa) on Escherichia coli and Listeria inncua strains. The morphological changes were evaluated using microscopy methods such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Epifluorescence Microscopy (EFM). The overall assessment of the physiological state of tested bacteria through TEM and SEM showed that the action of pressure on the structure of the bacterial membrane was almost minor or unnoticeable, beyond the L. innocua wild-type strain. However, alterations were observed in subcellular structures such as the cytoplasm and nucleoid for both L. innocua and E. coli strains. More significant changes after the HHP of internal structures were reported in the case of wild-type strains isolated from raw juice. Extreme condensation of the cytoplasm was observed, while the outline of cells was intact. The percentage ratio between alive and injured cells in the population was assessed by fluorescent microscopy. The results of HHP-treated samples showed a heterogeneous population, and red cell aggregates were observed. The percentage ratio of live and dead cells (L/D) in the L. innocua collection strain population was higher than in the case of the wild-type strain (69%/31% and 55%/45%, respectively). In turn, E. coli populations were characterized with a similar L/D ratio. Half of the cells in the populations were distinguished as visibly fluorescing red. The results obtained in this study confirmed sublethal HHP reaction on pathogens cells.
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Hight-Huf N, Nagar Y, Levi A, Pagaduan JN, Datar A, Katsumata R, Emrick T, Ramasubramaniam A, Naveh D, Barnes MD. Polarization-Driven Asymmetric Electronic Response of Monolayer Graphene to Polymer Zwitterions Probed from Both Sides. ACS Appl Mater Interfaces 2021; 13:47945-47953. [PMID: 34607423 DOI: 10.1021/acsami.1c13505] [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] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigated the nature of graphene surface doping by zwitterionic polymers and the implications of weak in-plane and strong through-plane screening using a novel sample geometry that allows direct access to either the graphene or the polymer side of a graphene/polymer interface. Using both Kelvin probe and electrostatic force microscopies, we observed a significant upshift in the Fermi level in graphene of ∼260 meV that was dominated by a change in polarizability rather than pure charge transfer with the organic overlayer. This physical picture is supported by density functional theory (DFT) calculations, which describe a redistribution of charge in graphene in response to the dipoles of the adsorbed zwitterionic moieties, analogous to a local DC Stark effect. Strong metallic-like screening of the adsorbed dipoles was observed by employing an inverted geometry, an effect identified by DFT to arise from a strongly asymmetric redistribution of charge confined to the side of graphene proximal to the zwitterion dipoles. Transport measurements confirm n-type doping with no significant impact on carrier mobility, thus demonstrating a route to desirable electronic properties in devices that combine graphene with lithographically patterned polymers.
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Affiliation(s)
- Nicholas Hight-Huf
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Yehiel Nagar
- Faculty of Engineering and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Adi Levi
- Faculty of Engineering and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - James Nicolas Pagaduan
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Avdhoot Datar
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Reika Katsumata
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Todd Emrick
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Ashwin Ramasubramaniam
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Doron Naveh
- Faculty of Engineering and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Michael D Barnes
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
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Houssat M, Villeneuve-Faure C, Lahoud Dignat N, Cambronne JP. Nanoscale mechanical and electrical characterization of the interphase in polyimide/silicon nitride nanocomposites. Nanotechnology 2021; 32:425703. [PMID: 34256368 DOI: 10.1088/1361-6528/ac13ea] [Citation(s) in RCA: 2] [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] [Received: 04/19/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Polymer nanocomposites (pNC) have attracted wide interests in electrical insulation applications. Compared to neat matrices or microcomposites, pNC provide significant improvements in combined electrical, mechanical and thermal properties. In the understanding of the reasons behind these improvements, a major role was attributed to the interphase, the interaction zone between the nanoparticles (NP) and the matrix. Because of their nanoscale dimensions, the interphase properties are mostly theoretically described but rarely experimentally characterized. The aim of this study is to propose a nanoscale measurement protocol in order to probe mechanical (Young modulus) and electrical (dielectric permittivity) interphase features using, respectively, the peak force quantitative nanomechanical (PF-QNM) and the electrostatic force microscopy (EFM) modes of the atomic force microscopy. Measurements are performed on polyimide/silicon nitride (Si3N4) nanocomposite and the effect of a silane coupling agent treatment of Si3N4NP is considered. In order to accurately probe mechanical properties in PF-QNM mode, the impacting parameters such as the applied force, the deformation and the topography are taken into account. The interphase region has shown a higher elastic modulus compared to the matrix and a higher width (WI) value for treated NP. From EFM measurements combined to a finite element model feeded with theWIvalues obtained from PF-QNM, the interphase permittivity is determined. The corresponding values are lower than the matrix one and similar for untreated and treated NP. This is in total agreement with its higher elastic modulus and implies that the interphase is a region around the NP where the polymer chains present a better organization and thus, a restricted mobility.
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Affiliation(s)
- Mohammed Houssat
- LAPLACE, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
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Houssat M, Villeneuve-Faure C, Lahoud Dignat N, Locatelli ML, Cambronne JP. Temperature Influence on PI/Si 3N 4 Nanocomposite Dielectric Properties: A Multiscale Approach. Polymers (Basel) 2021; 13:1936. [PMID: 34200956 DOI: 10.3390/polym13121936] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 11/16/2022] Open
Abstract
The interphase area appears to have a great impact on nanocomposite (NC) dielectric properties. However, the underlying mechanisms are still poorly understood, mainly because the interphase properties remain unknown. This is even more true if the temperature increases. In this study, a multiscale characterization of polyimide/silicon nitride (PI/Si3N4) NC dielectric properties is performed at various temperatures. Using a nanomechanical characterization approach, the interphase width was estimated to be 30 ± 2 nm and 42 ± 3 nm for untreated and silane-treated nanoparticles, respectively. At room temperature, the interphase dielectric permittivity is lower than that of the matrix. It increases with the temperature, and at 150 °C, the interphase and matrix permittivities reach the same value. At the macroscale, an improvement of the dielectric breakdown is observed at high temperature (by a factor of 2 at 300 °C) for NC compared to neat PI. The comparison between nano- and macro-scale measurements leads to the understanding of a strong correlation between interphase properties and NC ones. Indeed, the NC macroscopic dielectric permittivity is well reproduced from nanoscale permittivity results using mixing laws. Finally, a strong correlation between the interphase dielectric permittivity and NC breakdown strength is observed.
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Dinelli F, Fabbri F, Forti S, Coletti C, Kolosov OV, Pingue P. Scanning Probe Spectroscopy of WS 2/Graphene Van Der Waals Heterostructures. Nanomaterials (Basel) 2020; 10:E2494. [PMID: 33322575 PMCID: PMC7762982 DOI: 10.3390/nano10122494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 11/10/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 11/17/2022]
Abstract
In this paper, we present a study of tungsten disulfide (WS2) two-dimensional (2D) crystals, grown on epitaxial Graphene. In particular, we have employed scanning electron microscopy (SEM) and µRaman spectroscopy combined with multifunctional scanning probe microscopy (SPM), operating in peak force-quantitative nano mechanical (PF-QNM), ultrasonic force microscopy (UFM) and electrostatic force microscopy (EFM) modes. This comparative approach provides a wealth of useful complementary information and allows one to cross-analyze on the nanoscale the morphological, mechanical, and electrostatic properties of the 2D heterostructures analyzed. Herein, we show that PF-QNM can accurately map surface properties, such as morphology and adhesion, and that UFM is exceptionally sensitive to a broader range of elastic properties, helping to uncover subsurface features located at the buried interfaces. All these data can be correlated with the local electrostatic properties obtained via EFM mapping of the surface potential, through the cantilever response at the first harmonic, and the dielectric permittivity, through the cantilever response at the second harmonic. In conclusion, we show that combining multi-parametric SPM with SEM and µRaman spectroscopy helps to identify single features of the WS2/Graphene/SiC heterostructures analyzed, demonstrating that this is a powerful tool-set for the investigation of 2D materials stacks, a building block for new advanced nano-devices.
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Affiliation(s)
- Franco Dinelli
- CNR, Istituto Nazionale di Ottica, via Moruzzi 1, 56124 Pisa, Italy
| | - Filippo Fabbri
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy; (F.F.); (P.P.)
- NEST, Istituto di Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
- CNI@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy; (S.F.); (C.C.)
| | - Stiven Forti
- CNI@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy; (S.F.); (C.C.)
| | - Camilla Coletti
- CNI@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy; (S.F.); (C.C.)
- Graphene Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Oleg V. Kolosov
- Department of Physics, University of Lancaster, Bailrigg, Lancaster LA1 4YB, UK;
| | - Pasqualantonio Pingue
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy; (F.F.); (P.P.)
- NEST, Istituto di Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
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Guil F, Hidalgo JF, García JM. Flux Coupling and the Objective Functions' Length in EFMs. Metabolites 2020; 10:E489. [PMID: 33260526 DOI: 10.3390/metabo10120489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/18/2020] [Accepted: 11/24/2020] [Indexed: 11/24/2022] Open
Abstract
Structural analysis of constraint-based metabolic network models attempts to find the network’s properties by searching for subsets of suitable modes or Elementary Flux Modes (EFMs). One useful approach is based on Linear Program (LP) techniques, which introduce an objective function to convert the stoichiometric and thermodynamic constraints into a linear program (LP), using additional constraints to generate different nontrivial modes. This work introduces FLFS-FC (Fixed Length Function Sampling with Flux Coupling), a new approach to increase the efficiency of generation of large sets of different EFMs for the network. FLFS-FC is based on the importance of the length of the objective functions used in the associated LP problem and the imposition of additional negative constraints. Our proposal overrides some of the known drawbacks associated with the EFM extraction, such as the appearance of unfeasible problems or multiple repeated solutions arising from different LP problems.
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Goswami A, Alam KM, Kumar P, Kar P, Thundat T, Shankar K. Mapping the surface potential, charge density and adhesion of cellulose nanocrystals using advanced scanning probe microscopy. Carbohydr Polym 2020; 246:116393. [PMID: 32747225 DOI: 10.1016/j.carbpol.2020.116393] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 04/26/2020] [Accepted: 04/29/2020] [Indexed: 01/23/2023]
Abstract
Cellulose nanocrystals (CNC) are the focus of significant attention in the broad area of sustainable technologies for possessing many desirable properties such as a large surface area, high strength and stiffness, outstanding colloidal stability, excellent biocompatibility and biodegradability, low weight and abundance in nature. Yet, a fundamental understanding of the micro- and nanoscale electrical charge distribution on nanocellulose still remains elusive. Here we present direct quantification and mapping of surface charges on CNCs at ambient condition using advanced surface probe microscopy techniques such as Kelvin probe force microscopy (KPFM), electrostatic force microscopy (EFM) and force-distance (F-D) curve measurements. We show by EFM measurements that the surface charge in the solid-state (as contrasted with liquid dispersions) present at ambient condition on CNCs provided by Innotech Alberta is intrinsically negative and the charge density is estimated to be 13 μC/cm2. These charges also result in CNCs having two times the adhesive force exhibited by SiO2 substrates in adhesion mapping studies. The origin of negative surface charge is likely due to the formation of CNCs through sulfuric acid hydrolysis where sulfate half esters groups remained on the surface (Johnston et al., 2018).
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Cusanza SA, Speroni KG, Curran CA, Azizi D. Effect of individualized learning plans on nurse learning outcomes and risk mitigation. J Healthc Risk Manag 2020; 40:17-29. [PMID: 32929794 DOI: 10.1002/jhrm.21442] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION A "Primary Learner Assessment" (PLA) was created to provide an individualized learning plan, offering education as part of a 4-step computer-based process. The PLA is intended to improve learner's knowledge, skills, and patient safety perceptions, regarding interpretation of electronic fetal monitoring (EFM) data and administration of appropriate interventions in a timely fashion to mitigate fetal and maternal risks. Research was conducted to determine if learner knowledge, skills, and patient safety perceptions improved after completion of a 4-step computer-based, individualized adaptive-learning process. METHODS Participants were registered nurses (RNs) responsible for administering and interpreting EFM, from three U.S. hospitals with labor and delivery units. This mixed method pilot study was determined to be exempt by the institutional review board; all participants provided consent. The process included four steps. In step one, RNs completed the baseline PLA. Based on incorrect quantitative and EFM interpretation responses, computer-based EFM education courses were recommended (step two). After completion of recommended courses weeks or greater of practice (step three), the RNs completed a follow-up PLA (step four). RESULTS Of the 55 RN participants, most (85.5%) were clinical nurses, had a bachelor degree in nursing or higher (80.0%), and 11.2 average years of labor and delivery experience. There was a statistically significant improvement (P < .0001) in overall average percentage of correct PLA scores from baseline (76.7, SD = 9.1) to follow-up (82.5, SD = 6.9). Practice-related perceptions showed increased ranking of familiarity with the National Institute of Child Health and Human Development (NICHD) 2008 EFM terminology and guidelines from baseline of 49.0% to follow-up of 87.4% and of impact to which the participants integrated EFM administration and interpretation of NICHD EFM terminology and guidelines into practice from 52.8% at baseline to 94.5% at follow-up. In addition, RNs perceived improvement in their oxygen therapy competence and accuracy in interpreting EFM data with implementation of appropriate interventions. CONCLUSION These pilot study findings support a 4-step, computer-based individualized adaptive-learning process as RNs responsible for EFM to potentially mitigate fetal and maternal risk had improved knowledge and skills. Research is warranted in larger samples.
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Affiliation(s)
- Sharon A Cusanza
- Senior RM Education Specialist, Medical Interactive LLC (MI), One Galleria Blvd., Suite 700, Metairie, LA, 70001
| | - Karen Gabel Speroni
- Nursing Research Scientist, 43624 Merchant Mill Terrace, Leesburg, VA, 20176
| | - Carol A Curran
- Senior Educator, Perinatal Specialist & Business Development Specialist, Medical Interactive LLC (MI), One Galleria Blvd., Suite 700, Metairie, LA, 70001
| | - Dawer Azizi
- Vice President of Operations, Medical Interactive LLC (MI), One Galleria Blvd., Suite 700, Metairie, LA, 70001
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Wu Y, Wang D, Liu J, Cai H, Zhang Y. Atomic Force Microscope Study of Ag-Conduct Polymer Hybrid Films: Evidence for Light-Induced Charge Separation. Nanomaterials (Basel) 2020; 10:nano10091819. [PMID: 32932650 PMCID: PMC7558113 DOI: 10.3390/nano10091819] [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] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/28/2020] [Accepted: 09/03/2020] [Indexed: 11/16/2022]
Abstract
Scanning Kelvin probe microscopy (SKPM), electrostatic force microscopy (EFM) are used to study the microscopic processes of the photo-induced charge separation at the interface of Ag and conductive polymers, i.e., poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-bʹ]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and poly(3-hexylthiophene-2,5-diyl) (P3HT). They are also widely used in order to directly observe the charge distribution and dynamic changes at the interfaces in nanostructures, owing to their high sensitivity. Using SKPM, it is proved that the charge of the photo-induced polymer PCPDTBT is transferred to Ag nanoparticles (NPs). The surface charge of the Ag-induced NPs is quantified while using EFM, and it is determined that the charge is injected into the polymer P3HT from the Ag NPs. We expect that this technology will provide guidance to facilitate the separation and transfer of the interfacial charges in the composite material systems and it will be applicable to various photovoltaic material systems.
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Affiliation(s)
- Barry S Schifrin
- Department of Obstetrics & Gynecology, Western University of Health Sciences, Pomona, CA, United States
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Seidel JV, Castañeda-Uribe OA, Arevalo S, Muñoz F, Proud W, Avila A. Relative permittivity estimation of wheat starch: A critical property for understanding electrostatic hazards. J Hazard Mater 2019; 368:228-233. [PMID: 30682542 DOI: 10.1016/j.jhazmat.2019.01.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 07/23/2018] [Revised: 12/12/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
Wheat starch is a widely used material in the food, pharmaceutical and entertainment industry not considered hazard but recently associated to dust explosions during processing and handling. How an insulating starch grain is charged and how its ability to be polarized is affected by environmental conditions such as temperature, humidity and frequency? are fundamental questions that must be explored in order to understand the dust explosion phenomena. Here we investigate the dependence of temperature, humidity and low-frequency on the relative permittivity of wheat starch. We characterized starch at the micro and macro scales using atomic force microscopy-based techniques and capacitive planar sensor-based measurements respectively. The results show high values of permittivity (˜80) at the microscale (single starch grains) compared to the low values (10-20) at the macroscale (20 mg of wheat starch). The differences are attributed to the Maxwell-Wagner-Sillars interfacial polarization process on individual grains and potential charge exchange between grains. Permittivity is a critical property to investigate starch electrostatic hazards.
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Affiliation(s)
- J V Seidel
- Imperial College London, London, SW7 2BP, United Kingdom
| | - O A Castañeda-Uribe
- Vicerrectoría de Investigaciones, Grupo de Investigación en Ingeniería Biomédica (GIIB), Universidad Manuela Beltrán, Bogotá, DC 110231, Colombia
| | - S Arevalo
- Department of Electrical and Electronic Engineering and Centro de Microelectrónica (CMUA), Universidad de los Andes, Bogotá, 111711, Colombia
| | - F Muñoz
- Department of Chemical Engineering, Universidad de los Andes, Bogotá, 111711, Colombia
| | - W Proud
- Institute of Shock Physics, Imperial College London, London, SW7 2BP, United Kingdom
| | - A Avila
- Department of Electrical and Electronic Engineering and Centro de Microelectrónica (CMUA), Universidad de los Andes, Bogotá, 111711, Colombia.
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Stefani A, Högl B. Diagnostic Criteria, Differential Diagnosis, and Treatment of Minor Motor Activity and Less Well-Known Movement Disorders of Sleep. Curr Treat Options Neurol 2019; 21:1. [PMID: 30661130 PMCID: PMC6339673 DOI: 10.1007/s11940-019-0543-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose of review Sleep-related movement disorders (SRMD) include several different motor activities during sleep. Few of them are well known and well classified, whereas others are minor motor disorders of sleep which are neither thoroughly characterized and classified nor have been extensively investigated to clarify their pathogenesis and clinical relevance. This review will focus on those minor sleep-related movement disorders. Recent findings Before diagnosing periodic limb movement (PLM) disorder in patients with PLM during polysomnography, other disorders associated with PLM need to be excluded, namely restless legs syndrome (RLS), narcolepsy, REM sleep behavior disorder (RBD), and sleep-related breathing disorder. For the diagnosis of propriospinal myoclonus at sleep-onset, multi-channel surface electromyography recording during polysomnography is required and a possible psychogenic origin of the movement disorder has to be considered. Excessive fragmentary myoclonus (EFM) does not require symptomatic treatment, but further evaluation is suggested as electrophysiological abnormalities are present in 50% of cases. Nine percent of healthy sleepers meet the criteria for EFM, raising the question if current, arbitrarily defined, cutoffs are valid. Hypnagogic foot tremor, rhythmic feet movements, alternating leg muscle activation, and high-frequency leg movements are somewhat overlapping minor motor activities during sleep which may exist on their own or represent stereotyped movements to relieve RLS-like symptoms. Neck myoclonus is probably a physiological phenomenon related to REM twitching. RBD is formally a parasomnia but a relevant differential diagnosis when evaluating sleep-related movement disorders. In particular, prodromal RBD is characterized by electromyographic and behavioral findings on video-polysomnography which needs to be differentiated by minor sleep-related movement disorders. Summary Minor SRMD beyond the well-known main motor disorders of sleep should be correctly diagnosed, distinguished from differential diagnosis, and understood in their potential clinical relevance, in order also to start an appropriate treatment if needed.
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Affiliation(s)
- Ambra Stefani
- Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
| | - Birgit Högl
- Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
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Ogunyemi D, Jovanovski A, Friedman P, Sweatman B, Madan I. Temporal and quantitative associations of electronic fetal heart rate monitoring patterns and neonatal outcomes †. J Matern Fetal Neonatal Med 2018; 32:3115-3124. [PMID: 29621921 DOI: 10.1080/14767058.2018.1456523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Objective: The objective of this study is to evaluate the associations of electronic fetal heart rate monitoring (EFM) patterns and adverse neonatal outcomes Study design: From 2013 to 2016; 12,067 term, singleton deliveries in labor ≥2 h with abnormal EFM defined as absent accelerations, variable, late or prolonged decelerations, tachycardia, bradycardia, or minimal variability were analyzed as any documentation during labor, in first hour and last hour of labor. Outcomes were composite neonatal adverse outcomes, neonatal intensive care unit (NICU) admission, neonatal hypoxia, neonatal hypoglycemia, umbilical artery pH, and base excess. Independent associations were ascertained using regression analysis. Results: Significant independent associations occurred between any abnormal EFM during the last hour and five adverse neonatal outcomes; between abnormal EFM at any time and one adverse neonatal outcome while there was none with the first hour of labor. In the last hour, accelerations had significant negative associations with three adverse neonatal outcomes, while prolonged decelerations, late decelerations, tachycardia, and bradycardia had significant positive associations with three adverse neonatal outcomes. Throughout labor, increasing accelerations events were significantly negatively correlated with all adverse neonatal outcomes, while increasing frequency of late, variable, and prolonged decelerations were positively associated with five adverse neonatal outcomes. Hierarchical analysis showed that bradycardia/tachycardia contributed only 0.8%, while all EFM periodic changes contributed 1%; the addition of the frequencies of abnormal EFM events contributed 0.6% to the variance in umbilical artery pH and base excess. Conclusions: Terminal EFM patterns are independently associated with neonatal outcomes. Accelerations are protective of adverse neonatal outcomes. Increasing frequency of EFM patterns overtime contributes to neonatal outcome.
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Affiliation(s)
- Dotun Ogunyemi
- a Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology , Beaumont Hospital , Royal Oak , MI , USA.,b William Beaumont School of Medicine , Oakland University , Rochester Hills , MI , USA
| | - Andrew Jovanovski
- b William Beaumont School of Medicine , Oakland University , Rochester Hills , MI , USA
| | - Perry Friedman
- a Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology , Beaumont Hospital , Royal Oak , MI , USA.,b William Beaumont School of Medicine , Oakland University , Rochester Hills , MI , USA
| | - Brittany Sweatman
- b William Beaumont School of Medicine , Oakland University , Rochester Hills , MI , USA
| | - Ichchha Madan
- a Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology , Beaumont Hospital , Royal Oak , MI , USA.,b William Beaumont School of Medicine , Oakland University , Rochester Hills , MI , USA
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Clop EM, Corvalán NA, Perillo MA. Langmuir films of dipalmitoyl phosphatidylethanolamine grafted poly(ethylene glycol). In-situ evidence of surface aggregation at the air-water interface. Colloids Surf B Biointerfaces 2016; 148:640-649. [PMID: 27697738 DOI: 10.1016/j.colsurfb.2016.09.023] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/25/2016] [Accepted: 09/20/2016] [Indexed: 10/21/2022]
Abstract
The molecular packing-dependent interfacial organization of polyethylene glycol grafted dipalmitoylphosphatidylethanolamine (PE-PEGs) Langmuir films was studied. The PEG chains covered a wide molecular mass range (350, 1000 and 5000Da). In surface pressure-area (π-A), isotherms PE-PEG1000 and PE-PEG5000 showed transitions (midpoints at πm,t1∼11mN/m, "t1"), which appeared as a long non-horizontal line region. Thus, t1 cannot be considered a first-order phase transition but may reflect a transition within the polymer, comprising its desorption from the air-water interface and compaction upon compression. This is supported by the increase in the νs(C-O-C) PM-IRRAS signal intensity and the increasing surface potentials at maximal compression, which reflect thicker polymeric layers. Furthermore, changes in hydrocarbon chain (HC) packing and tilt with respect to the surface led to reorientation in the PO2- group upon compression, indicated by the inversion of the νasym(PO2-) PM-IRRAS signal around t1. The absence of a t1 in PE-PEG350 supports the requisite of a critical polymer chain length for this transition to occur. In-situ epifluorescence microscopy revealed 2D-domain-like structures in PE-PEG1000 and PE-PEG5000 around t1, possibly associated with gelation/dehydration of the polymeric layer and appearing at decreasing π as the polymeric tail became longer. Another transition, t2, appearing in PE-PEG350 and PE-PEG1000 at πm,t2=29.4 and 34.8mN/m, respectively, was associated with HC condensation and was impaired in PE-PEG5000 due to steric hindrance imposed by the large size of its polymer moiety. Two critical lengths of polymer chains were found, one of which allowed the onset of polymeric-tail gelation and the other limited HC compaction.
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Affiliation(s)
- Eduardo M Clop
- Instituto de Investigaciones Biológicas y Tecnológicas IIBYT (CONICET-UNC) Cátedra de Química Biológica, Depto de Química, FCEFyN, Universidad Nacional de Córdoba. Av. Vélez Sarsfield 1611, X 5016GCA Córdoba, Argentina
| | - Natalia A Corvalán
- Instituto de Investigaciones Biológicas y Tecnológicas IIBYT (CONICET-UNC) Cátedra de Química Biológica, Depto de Química, FCEFyN, Universidad Nacional de Córdoba. Av. Vélez Sarsfield 1611, X 5016GCA Córdoba, Argentina
| | - María A Perillo
- Instituto de Investigaciones Biológicas y Tecnológicas IIBYT (CONICET-UNC) Cátedra de Química Biológica, Depto de Química, FCEFyN, Universidad Nacional de Córdoba. Av. Vélez Sarsfield 1611, X 5016GCA Córdoba, Argentina.
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Cadena MJ, Sung SH, Boudouris BW, Reifenberger R, Raman A. Nanoscale Mapping of Dielectric Properties of Nanomaterials from Kilohertz to Megahertz Using Ultrasmall Cantilevers. ACS Nano 2016; 10:4062-4071. [PMID: 26972782 DOI: 10.1021/acsnano.5b06893] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electrostatic force microscopy (EFM) is often used for nanoscale dielectric spectroscopy, the measurement of local dielectric properties of materials as a function of frequency. However, the frequency range of atomic force microscopy (AFM)-based dielectric spectroscopy has been limited to a few kilohertz by the resonance frequency and noise of soft microcantilevers used for this purpose. Here, we boost the frequency range of local dielectric spectroscopy by 3 orders of magnitude from a few kilohertz to a few megahertz by developing a technique that exploits the high resonance frequency and low thermal noise of ultrasmall cantilevers (USCs). We map the frequency response of the real and imaginary components of the capacitance gradient (∂C(ω)/∂z) by using second-harmonic EFM and a theoretical model, which relates cantilever dynamics to the complex dielectric constant. We demonstrate the method by mapping the nanoscale dielectric spectrum of polymer-based materials for organic electronic devices. Beyond offering a powerful extension to AFM-based dielectric spectroscopy, the approach also allows the identification of electrostatic excitation frequencies which affords high dielectric contrast on nanomaterials.
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Affiliation(s)
- Maria J Cadena
- School of Mechanical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Seung Hyun Sung
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Bryan W Boudouris
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Ronald Reifenberger
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
- Department of Physics, Purdue University , West Lafayette, Indiana 47907, United States
| | - Arvind Raman
- School of Mechanical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
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de León A, Arias E, Moggio I, Gallardo-Vega C, Ziolo R, Rodríguez O, Trigari S, Giorgetti E, Leibig C, Evans D. Synthesis of mercaptopropyl-(phenylene)s-benzoates passivated gold nanoparticles: Implications for plasmonic photovoltaic cells. J Colloid Interface Sci 2015; 456:182-9. [PMID: 26122799 DOI: 10.1016/j.jcis.2015.06.029] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/15/2015] [Accepted: 06/16/2015] [Indexed: 10/23/2022]
Abstract
UNLABELLED The incorporation of gold nanoparticles in heterojunction solar cells is expected to increase the efficiency due to plasmon effects, but the literature studies are sometimes controversial. In this work, gold nanoparticles passivated with (Ph)n-(CH2)3SH (n=1, 2, 3) have been synthesized by reduction of tetrachloroauric acid with sodium borohydride in two ways: (1) one-phase where both the thiol and the gold salt are solubilized in a mixture of methanol with acetic acid: Au-s-(Ph)n or (2), two-phase, using tetraoctylammonium bromide (TOAB) to transfer gold from water to toluene where the thiol is solubilized, Au(TOAB)-s-(Ph)n. The morphological, experimental and simulated optical properties were studied and analyzed as a function of the thiol and of the synthetic procedure in order to correlate them with the efficiency of plasmonic hybrid solar cells in the following configuration ITO/PEDOT:PSS/P3HT:PCBM-C60:Au-nanoparticles/Field's metal, where PEDOT PSS is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), P3HT is poly(3-hexylthiophene-2,5-diyl) and PCBM-C60 is [6,6]-Phenyl C61 butyric acid methyl ester. Our findings indicate that the gold nanoparticles incorporation is affecting the electrical properties of the active layer giving a maximum efficiency for Au-s-(Ph)3. Moreover, TOAB, which is usually used in the synthesis of thiol passivated gold nanoparticles, has negative effects in both plasmonic and electrical properties. This result is important for optoelectronic applications of gold nanoparticles prepared with any procedures that involve TOAB.
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Affiliation(s)
- Arxel de León
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Eduardo Arias
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Ivana Moggio
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Carlos Gallardo-Vega
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Ronald Ziolo
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Oliverio Rodríguez
- Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila, Mexico.
| | - Silvana Trigari
- Istituto dei Sistemi Complessi, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy.
| | - Emilia Giorgetti
- Istituto dei Sistemi Complessi, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy.
| | - Carl Leibig
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH 45433, USA.
| | - Dean Evans
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH 45433, USA.
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Wu S, Wu Z, Lin D, Zhong Z, Jiang Z, Yang X. Photogenerated charges and surface potential variations investigated on single Si nanorods by electrostatic force microscopy combined with laser irradiation. Nanoscale Res Lett 2014; 9:245. [PMID: 24940176 PMCID: PMC4035825 DOI: 10.1186/1556-276x-9-245] [Citation(s) in RCA: 6] [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] [Received: 03/04/2014] [Accepted: 05/07/2014] [Indexed: 06/02/2023]
Abstract
Photogenerated charging properties of single Si nanorods (Si NRs) are investigated by electrostatic force microscopy (EFM) combined with laser irradiation. Under laser irradiation, Si NRs are positively charged. The amount of the charges trapped in single NRs as well as the contact potential difference between the tip and NRs' surface is achieved from an analytical fitting of the phase shift - voltage curve. Both of them significantly vary with the laser intensity and the NR's size and construction. The photogenerated charging and decharging rates are obtained at a timescale of seconds or slower, indicating that the Si NRs are promising candidates in photovoltaic applications.
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Affiliation(s)
- Shan Wu
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
| | - Zilong Wu
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
| | - Dongdong Lin
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
| | - Zhenyang Zhong
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
| | - Zuimin Jiang
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
| | - Xinju Yang
- State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
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Shah N, Ul-Islam M, Khattak WA, Park JK. Overview of bacterial cellulose composites: a multipurpose advanced material. Carbohydr Polym 2013; 98:1585-98. [PMID: 24053844 DOI: 10.1016/j.carbpol.2013.08.018] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/02/2013] [Accepted: 08/05/2013] [Indexed: 11/22/2022]
Abstract
Bacterial cellulose (BC) has received substantial interest owing to its unique structural features and impressive physico-mechanical properties. BC has a variety of applications in biomedical fields, including use as biomaterial for artificial skin, artificial blood vessels, vascular grafts, scaffolds for tissue engineering, and wound dressing. However, pristine BC lacks certain properties, which limits its applications in various fields; therefore, synthesis of BC composites has been conducted to address these limitations. A variety of BC composite synthetic strategies have been developed based on the nature and relevant applications of the combined materials. BC composites are primarily synthesized through in situ addition of reinforcement materials to BC synthetic media or the ex situ penetration of such materials into BC microfibrils. Polymer blending and solution mixing are less frequently used synthetic approaches. BC composites have been synthesized using numerous materials ranging from organic polymers to inorganic nanoparticles. In medical fields, these composites are used for tissue regeneration, healing of deep wounds, enzyme immobilization, and synthesis of medical devices that could replace cardiovascular and other connective tissues. Various electrical products, including biosensors, biocatalysts, E-papers, display devices, electrical instruments, and optoelectronic devices, are prepared from BC composites with conductive materials. In this review, we compiled various synthetic approaches for BC composite synthesis, classes of BC composites, and applications of BC composites. This study will increase interest in BC composites and the development of new ideas in this field.
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