1
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Koide E, Mohardt ML, Doctor ZM, Yang A, Hao M, Donovan KA, Kuismi CC, Nelson AJ, Abell K, Aguiar M, Che J, Stokes MP, Zhang T, Aguirre AJ, Fischer ES, Gray NS, Jiang B, Nabet B. Development and Characterization of Selective FAK Inhibitors and PROTACs with In Vivo Activity. Chembiochem 2023; 24:e202300141. [PMID: 37088717 PMCID: PMC10590827 DOI: 10.1002/cbic.202300141] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 04/25/2023]
Abstract
Focal adhesion kinase (FAK) is an attractive drug target due to its overexpression in cancer. FAK functions as a non-receptor tyrosine kinase and scaffolding protein, coordinating several downstream signaling effectors and cellular processes. While drug discovery efforts have largely focused on targeting FAK kinase activity, FAK inhibitors have failed to show efficacy as single agents in clinical trials. Here, using structure-guided design, we report the development of a selective FAK inhibitor (BSJ-04-175) and degrader (BSJ-04-146) to evaluate the consequences and advantages of abolishing all FAK activity in cancer models. BSJ-04-146 achieves rapid and potent FAK degradation with high proteome-wide specificity in cancer cells and induces durable degradation in mice. Compared to kinase inhibition, targeted degradation of FAK exhibits pronounced improved activity on downstream signaling and cancer cell viability and migration. Together, BSJ-04-175 and BSJ-04-146 are valuable chemical tools to dissect the specific consequences of targeting FAK through small-molecule inhibition or degradation.
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Affiliation(s)
- Eriko Koide
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Mikaela L. Mohardt
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Zainab M. Doctor
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Annan Yang
- Harvard Medical School, Boston, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Mingfeng Hao
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Katherine A. Donovan
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | - Jianwei Che
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | | | - Tinghu Zhang
- Department of Chemical and Systems Biology, Chem-H and Stanford Cancer Institute, Stanford Medicine, Stanford University, Stanford, CA, USA
| | - Andrew J. Aguirre
- Harvard Medical School, Boston, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Eric S. Fischer
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Nathanael S. Gray
- Department of Chemical and Systems Biology, Chem-H and Stanford Cancer Institute, Stanford Medicine, Stanford University, Stanford, CA, USA
| | - Baishan Jiang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Behnam Nabet
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
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2
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Searle BC, Chien A, Koller A, Hawke D, Herren AW, Kim Kim J, Lee KA, Leib RD, Nelson AJ, Patel P, Ren JM, Stemmer PM, Zhu Y, Neely BA, Patel B. A Multipathway Phosphopeptide Standard for Rapid Phosphoproteomics Assay Development. Mol Cell Proteomics 2023; 22:100639. [PMID: 37657519 PMCID: PMC10561125 DOI: 10.1016/j.mcpro.2023.100639] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/03/2023] Open
Abstract
Recent advances in methodology have made phosphopeptide analysis a tractable problem for many proteomics researchers. There are now a wide variety of robust and accessible enrichment strategies to generate phosphoproteomes while free or inexpensive software tools for quantitation and site localization have simplified phosphoproteome analysis workflow tremendously. As a research group under the Association for Biomolecular Resource Facilities umbrella, the Proteomics Standards Research Group has worked to develop a multipathway phosphopeptide standard based on a mixture of heavy-labeled phosphopeptides designed to enable researchers to rapidly develop assays. This mixture contains 131 mass spectrometry vetted phosphopeptides specifically chosen to cover as many known biologically interesting phosphosites as possible from seven different signaling networks: AMPK signaling, death and apoptosis signaling, ErbB signaling, insulin/insulin-like growth factor-1 signaling, mTOR signaling, PI3K/AKT signaling, and stress (p38/SAPK/JNK) signaling. Here, we describe a characterization of this mixture spiked into a HeLa tryptic digest stimulated with both epidermal growth factor and insulin-like growth factor-1 to activate the MAPK and PI3K/AKT/mTOR pathways. We further demonstrate a comparison of phosphoproteomic profiling of HeLa performed independently in five labs using this phosphopeptide mixture with data-independent acquisition. Despite different experimental and instrumentation processes, we found that labs could produce reproducible, harmonized datasets by reporting measurements as ratios to the standard, while intensity measurements showed lower consistency between labs even after normalization. Our results suggest that widely available, biologically relevant phosphopeptide standards can act as a quantitative "yardstick" across laboratories and sample preparations enabling experimental designs larger than a single laboratory can perform. Raw data files are publicly available in the MassIVE dataset MSV000090564.
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Affiliation(s)
- Brian C Searle
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio, USA; Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, USA.
| | - Allis Chien
- Mass Spectrometry Center, Stanford University, Stanford, California, USA
| | | | | | - Anthony W Herren
- UC Davis Genome Center, Proteomics Core, University of California Davis, Davis California, USA
| | - Jenny Kim Kim
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, USA
| | - Kimberly A Lee
- Cell Signaling Technology, Inc, Danvers, Massachusetts, USA
| | - Ryan D Leib
- Mass Spectrometry Center, Stanford University, Stanford, California, USA
| | | | - Purvi Patel
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, USA
| | - Jian Min Ren
- Cell Signaling Technology, Inc, Danvers, Massachusetts, USA
| | - Paul M Stemmer
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan, USA
| | - Yiying Zhu
- Cell Signaling Technology, Inc, Danvers, Massachusetts, USA
| | - Benjamin A Neely
- National Institute of Standards and Technology, Charleston, South Carolina, USA
| | - Bhavin Patel
- Thermo Fisher Scientific, Rockford, Illinois, USA
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3
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Applebaum AJ, Sannes T, Mitchell HR, McAndrew NS, Wiener L, Knight JM, Nelson AJ, Gray TF, Fank PM, Lahijani SC, Pozo-Kaderman C, Rueda-Lara M, Miran DM, Landau H, Amonoo HL. Fit for Duty: Lessons Learned from Outpatient and Homebound Hematopoietic Cell Transplantation to Prepare Family Caregivers for Home-Based Care. Transplant Cell Ther 2023; 29:143-150. [PMID: 36572386 PMCID: PMC9780643 DOI: 10.1016/j.jtct.2022.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
In the past decade, the demand for home-based care has been amplified by the Coronavirus disease 2019 pandemic. Home-based care has significant benefits for patients, their families, and healthcare systems, but it relies on the often-invisible workforce of family and friend caregivers who shoulder essential health care responsibilities, frequently with inadequate training and support. Hematopoietic cell transplantation (HCT), a potentially curative but intensive treatment for many patients with blood disorders, is being increasingly offered in home-based care settings and necessitates the involvement of family caregivers for significant patient care responsibilities. However, guidelines for supporting and preparing HCT caregivers to effectively care for their loved ones at home have not yet been established. Here, informed by the literature and our collective experience as clinicians and researchers who care for diverse patients with hematologic malignancies undergoing HCT, we provide considerations and recommendations to better support and prepare family caregivers in home-based HCT and, by extension, family caregivers supporting patients with other serious illnesses at home. We suggest tangible ways to screen family caregivers for distress and care delivery challenges, educate and train them to prepare for their caregiving role, and create an infrastructure of support for family caregivers within this emerging care delivery model.
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Affiliation(s)
- A J Applebaum
- Department of Psychiatry and Behavioral Sciences, Memorial Sloan Kettering Cancer Center, New York, New York.
| | - T Sannes
- Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - H R Mitchell
- Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, New York
| | - N S McAndrew
- College of Nursing, University of Wisconsin-Milwaukee, Milwaukee, WI, USA; Froedtert & the Medical College of Wisconsin, Froedtert Hospital, Patient Care Research, Milwaukee, Wisconsin
| | - L Wiener
- Pediatric Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, MD
| | - J M Knight
- Departments of Psychiatry, Medicine, and Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - A J Nelson
- Department of Psychiatry, Harvard Medical School/Massachusetts General Hospital, Boston, Massachusetts
| | - T F Gray
- Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - P M Fank
- Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, Illinois
| | - S C Lahijani
- Department of Psychiatry & Behavioral Sciences, Division of Medical Psychiatry, Stanford University School of Medicine, Palo Alto, California
| | - C Pozo-Kaderman
- Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - M Rueda-Lara
- University of Miami/Leonard Miller School of Medicine, Department of Psychiatry and Behavioral Sciences, Sylvester Comprehensive Cancer Center, Miami, Florida
| | - D M Miran
- Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - H Landau
- Adult Bone Marrow Transplant Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - H L Amonoo
- Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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4
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Rivera KD, Olive ME, Bergstrom EJ, Nelson AJ, Lee KA, Satpathy S, Carr SA, Udeshi ND. Automating UbiFast for High-throughput and Multiplexed Ubiquitin Enrichment. Mol Cell Proteomics 2021; 20:100154. [PMID: 34592423 PMCID: PMC9357436 DOI: 10.1016/j.mcpro.2021.100154] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 05/05/2021] [Revised: 08/23/2021] [Accepted: 09/22/2021] [Indexed: 01/11/2023] Open
Abstract
Robust methods for deep-scale enrichment and site-specific identification of ubiquitylation sites are necessary for characterizing the myriad roles of protein ubiquitylation. To this end we previously developed UbiFast, a sensitive method for highly multiplexed ubiquitylation profiling where K-ϵ-GG peptides are enriched with anti-K-ε-GG antibody and labeled on-antibody with isobaric labeling reagents for sample multiplexing. Here, we present robotic automation of the UbiFast method using a magnetic bead-conjugated K-ε-GG antibody (mK-ε-GG) and a magnetic particle processor. We report the identification of ∼20,000 ubiquitylation sites from a TMT10-plex with 500 μg input per sample processed in ∼2 h. Automation of the UbiFast method greatly increased the number of identified and quantified ubiquitylation sites, improved reproducibility, and significantly reduced processing time. The automated method also significantly reduced variability across process replicates compared with the manual method. The workflow enables processing of up to 96 samples in a single day making it suitable to study ubiquitylation in large sample sets. Here we demonstrate the applicability of the method to profile small amounts of tissue using breast cancer patient–derived xenograft (PDX) tissue samples. HS mag anti-K-ε-GG antibody increases sensitivity of ubiquitylation site detection. Automated UbiFast increases reproducibility and sample processing throughput. The automated UbiFast workflow enables processing of up to 96 samples in one day. UbiFast can be employed to profile ubiquitylomes from small amounts of tumor tissue.
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Affiliation(s)
- Keith D Rivera
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Meagan E Olive
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Erik J Bergstrom
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | | | - Shankha Satpathy
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.
| | - Namrata D Udeshi
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.
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5
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Mulvaney KM, Blomquist C, Acharya N, Li R, Ranaghan MJ, O'Keefe M, Rodriguez DJ, Young MJ, Kesar D, Pal D, Stokes M, Nelson AJ, Jain SS, Yang A, Mullin-Bernstein Z, Columbus J, Bozal FK, Skepner A, Raymond D, LaRussa S, McKinney DC, Freyzon Y, Baidi Y, Porter D, Aguirre AJ, Ianari A, McMillan B, Sellers WR. Molecular basis for substrate recruitment to the PRMT5 methylosome. Mol Cell 2021; 81:3481-3495.e7. [PMID: 34358446 DOI: 10.1016/j.molcel.2021.07.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/07/2021] [Accepted: 07/14/2021] [Indexed: 12/15/2022]
Abstract
PRMT5 is an essential arginine methyltransferase and a therapeutic target in MTAP-null cancers. PRMT5 uses adaptor proteins for substrate recruitment through a previously undefined mechanism. Here, we identify an evolutionarily conserved peptide sequence shared among the three known substrate adaptors (CLNS1A, RIOK1, and COPR5) and show that it is necessary and sufficient for interaction with PRMT5. We demonstrate that PRMT5 uses modular adaptor proteins containing a common binding motif for substrate recruitment, comparable with other enzyme classes such as kinases and E3 ligases. We structurally resolve the interface with PRMT5 and show via genetic perturbation that it is required for methylation of adaptor-recruited substrates including the spliceosome, histones, and ribosomal complexes. Furthermore, disruption of this site affects Sm spliceosome activity, leading to intron retention. Genetic disruption of the PRMT5-substrate adaptor interface impairs growth of MTAP-null tumor cells and is thus a site for development of therapeutic inhibitors of PRMT5.
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Affiliation(s)
| | | | | | | | - Matthew J Ranaghan
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | - Meghan O'Keefe
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | - Adam Skepner
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | - Donald Raymond
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | - Salvatore LaRussa
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | - David C McKinney
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA
| | | | | | - Dale Porter
- Broad Institute, Cambridge, MA, USA; Cedilla Therapeutics, Cambridge, MA, USA
| | - Andrew J Aguirre
- Broad Institute, Cambridge, MA, USA; Medical Oncology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | | | - Brian McMillan
- Center for the Development of Therapeutics, Broad Institute, Cambridge, MA, USA; Tango Therapeutics, Cambridge, MA, USA
| | - William R Sellers
- Broad Institute, Cambridge, MA, USA; Medical Oncology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA.
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6
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Wyatt TA, Nemecek M, Chandra D, DeVasure JM, Nelson AJ, Romberger DJ, Poole JA. Organic dust-induced lung injury and repair: Bi-directional regulation by TNFα and IL-10. J Immunotoxicol 2020; 17:153-162. [PMID: 32634062 DOI: 10.1080/1547691x.2020.1776428] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 12/15/2022] Open
Abstract
Exposure to organic dust increases chronic airway inflammatory disorders. Effective treatment strategies are lacking. It has been reported that hog barn dust extracts (HDE) induce TNFα through protein kinase C (PKC) activation and that lung inflammation is enhanced in scavenger receptor A (SRA/CD204) knockout (KO) mice following HDE. Because interleukin (IL)-10 production can limit excessive inflammation, it was hypothesized here that HDE-induced IL-10 would require CD204 to effect inflammatory responses. C57BL/6 wild-type (WT), SRA KO, and IL-10 KO mice were intranasally challenged daily for 8 days with HDE and subsequently rested for 3 days with/without recombinant IL-10 (rIL-10) treatment. Primary peritoneal macrophages (PM) and murine alveolar macrophages (MH-S cells) were treated in vitro with HDE, SRA ligand (fucoidan), rIL-10, and/or PKC isoform inhibitors. HDE induced in vivo lung IL-10 in WT, but not SRA KO mice, and similar trends were demonstrated in isolated PM from same treated mice. Lung lymphocyte aggregates and neutrophils were elevated in in vivo HDE-treated SRA and IL-10 KO mice after a 3-d recovery, and treatment during recovery with rIL-10 abrogated these responses. In vitro rIL-10 treatment reduced HDE-stimulated TNFα release in MH-S and WT PM. In SRA KO macrophages, there was reduced IL-10 and PKC zeta (ζ) activity and increased TNFα following in vitro HDE stimulation. Similarly, blocking SRA (24 hr fucoidan pre-treatment) resulted in enhanced HDE-stimulated macrophage TNFα and decreased IL-10 and PKCζ activation. PKCζ inhibitors blocked HDE-stimulated IL-10, but not TNFα. Collectively, HDE stimulates IL-10 by an SRA- and PKCζ-dependent mechanism to regulate TNFα. Enhancing resolution of dust-mediated lung inflammation through targeting IL-10 and/or SRA may represent new approaches to therapeutic interventions.
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Affiliation(s)
- T A Wyatt
- Pulmonary, Critical Care, and Sleep, University of Nebraska Medical Center, Omaha, NE, USA.,Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE, USA.,Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, USA
| | - M Nemecek
- Pulmonary, Critical Care, and Sleep, University of Nebraska Medical Center, Omaha, NE, USA.,Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE, USA
| | - D Chandra
- Pulmonary, Critical Care, and Sleep, University of Nebraska Medical Center, Omaha, NE, USA
| | - J M DeVasure
- Pulmonary, Critical Care, and Sleep, University of Nebraska Medical Center, Omaha, NE, USA
| | - A J Nelson
- Allergy and Immunology Divisions, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - D J Romberger
- Pulmonary, Critical Care, and Sleep, University of Nebraska Medical Center, Omaha, NE, USA.,Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, USA
| | - J A Poole
- Allergy and Immunology Divisions, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
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7
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Welsh H, Nelson AJ, van der Merwe AE, de Boer HH, Brickley MB. An Investigation of Micro-CT Analysis of Bone as a New Diagnostic Method for Paleopathological Cases of Osteomalacia. Int J Paleopathol 2020; 31:23-33. [PMID: 32927328 DOI: 10.1016/j.ijpp.2020.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 06/04/2020] [Revised: 08/03/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE This paper looks to broaden the methodological possibilities for diagnosing osteomalacia in archaeological bone using micro-CT analysis. Increasing the identification of osteomalacia in paleopathology will provide support for important interpretive frameworks. MATERIALS Nine embedded and two unembedded rib fragments were sourced from St. Martin's Birmingham and Ancaster, UK, and Lisieux Michelet, France. Of the 11 samples, nine were previously confirmed as osteomalacic, and presented with varying levels of diagenesis and two were non-osteomalacic controls, one of which exhibits diagenetic change. METHODS Micro-CT, backscattered scanning electron microscopy, and light microscopy were employed. Micro-CT images were evaluated for osteomalacic features using corresponding microscopic images. RESULTS Micro-CT images from osteomalacic samples demonstrated the presence of defective mineralization adjacent to cement lines, areas of incomplete mineralization, and resorptive bays/borders, three key diagnostic features of osteomalacia. Diagenetic change was also detectable in micro-CT images, but did not prevent the diagnosis of osteomalacia. CONCLUSIONS Micro-CT analysis is a non-destructive method capable of providing microstructural images of osteomalacic features in embedded and unembedded samples. When enough of these features are present, micro-CT images are capable of confirming a diagnosis of osteomalacia. SIGNIFICANCE Vitamin D deficiency has important health consequences which operate throughout the life course. Increasing the ability to detect cases of vitamin D deficiency provides researchers with a greater understanding of health and disease in past communities. LIMITATIONS Only adult rib samples were used. SUGGESTIONS FOR FURTHER RESEARCH Paleopathologists should look to test the utility of micro-CT analysis in diagnosing active rickets in subadult individuals.
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Affiliation(s)
- H Welsh
- Department of Anthropology, McMaster University, Hamilton, ON, L8S 4L9, Canada.
| | - A J Nelson
- Departments of Anthropology and Chemistry, Bone and Joint Institute, The University of Western Ontario, London, ON, N6A 5C3, Canada
| | - A E van der Merwe
- Department of Medical Biology, Section Clinical Anatomy and Embryology, Amsterdam University Medical Centres, Location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - H H de Boer
- Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands; Department of Forensic Medicine, Netherlands Forensic Institute, The Hague, The Netherlands
| | - M B Brickley
- Department of Anthropology, McMaster University, Hamilton, ON, L8S 4L9, Canada
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8
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Houston R, Sekine S, Calderon MJ, Seifuddin F, Wang G, Kawagishi H, Malide DA, Li Y, Gucek M, Pirooznia M, Nelson AJ, Stokes MP, Stewart-Ornstein J, Mullett SJ, Wendell SG, Watkins SC, Finkel T, Sekine Y. Acetylation-mediated remodeling of the nucleolus regulates cellular acetyl-CoA responses. PLoS Biol 2020; 18:e3000981. [PMID: 33253182 PMCID: PMC7728262 DOI: 10.1371/journal.pbio.3000981] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 12/10/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
The metabolite acetyl-coenzyme A (acetyl-CoA) serves as an essential element for a wide range of cellular functions including adenosine triphosphate (ATP) production, lipid synthesis, and protein acetylation. Intracellular acetyl-CoA concentrations are associated with nutrient availability, but the mechanisms by which a cell responds to fluctuations in acetyl-CoA levels remain elusive. Here, we generate a cell system to selectively manipulate the nucleo-cytoplasmic levels of acetyl-CoA using clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing and acetate supplementation of the culture media. Using this system and quantitative omics analyses, we demonstrate that acetyl-CoA depletion alters the integrity of the nucleolus, impairing ribosomal RNA synthesis and evoking the ribosomal protein-dependent activation of p53. This nucleolar remodeling appears to be mediated through the class IIa histone deacetylases (HDACs). Our findings highlight acetylation-mediated control of the nucleolus as an important hub linking acetyl-CoA fluctuations to cellular stress responses.
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Affiliation(s)
- Ryan Houston
- Aging Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shiori Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Michael J. Calderon
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Fayaz Seifuddin
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Guanghui Wang
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Hiroyuki Kawagishi
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Daniela A. Malide
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Yuesheng Li
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Marjan Gucek
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Mehdi Pirooznia
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Alissa J. Nelson
- Cell Signaling Technology, INC., Danvers, Massachusetts, United States of America
| | - Matthew P. Stokes
- Cell Signaling Technology, INC., Danvers, Massachusetts, United States of America
| | - Jacob Stewart-Ornstein
- Department of Computational and Systems Biology, University of Pittsburgh and Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Steven J. Mullett
- Department of Pharmacology and Chemical Biology, the Health Sciences Metabolomics and Lipidomics Core, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Stacy G. Wendell
- Department of Pharmacology and Chemical Biology, the Health Sciences Metabolomics and Lipidomics Core, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Simon C. Watkins
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Toren Finkel
- Aging Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Yusuke Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, United States of America
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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9
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Sharma V, Sood R, Khlaifia A, Eslamizade MJ, Hung TY, Lou D, Asgarihafshejani A, Lalzar M, Kiniry SJ, Stokes MP, Cohen N, Nelson AJ, Abell K, Possemato AP, Gal-Ben-Ari S, Truong VT, Wang P, Yiannakas A, Saffarzadeh F, Cuello AC, Nader K, Kaufman RJ, Costa-Mattioli M, Baranov PV, Quintana A, Sanz E, Khoutorsky A, Lacaille JC, Rosenblum K, Sonenberg N. eIF2α controls memory consolidation via excitatory and somatostatin neurons. Nature 2020; 586:412-416. [PMID: 33029011 PMCID: PMC7874887 DOI: 10.1038/s41586-020-2805-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
An important tenet of learning and memory is the notion of a molecular switch that promotes the formation of long-term memory1-4. The regulation of proteostasis is a critical and rate-limiting step in the consolidation of new memories5-10. One of the most effective and prevalent ways to enhance memory is by regulating the synthesis of proteins controlled by the translation initiation factor eIF211. Phosphorylation of the α-subunit of eIF2 (p-eIF2α), the central component of the integrated stress response (ISR), impairs long-term memory formation in rodents and birds11-13. By contrast, inhibiting the ISR by mutating the eIF2α phosphorylation site, genetically11 and pharmacologically inhibiting the ISR kinases14-17, or mimicking reduced p-eIF2α with the ISR inhibitor ISRIB11, enhances long-term memory in health and disease18. Here we used molecular genetics to dissect the neuronal circuits by which the ISR gates cognitive processing. We found that learning reduces eIF2α phosphorylation in hippocampal excitatory neurons and a subset of hippocampal inhibitory neurons (those that express somatostatin, but not parvalbumin). Moreover, ablation of p-eIF2α in either excitatory or somatostatin-expressing (but not parvalbumin-expressing) inhibitory neurons increased general mRNA translation, bolstered synaptic plasticity and enhanced long-term memory. Thus, eIF2α-dependent mRNA translation controls memory consolidation via autonomous mechanisms in excitatory and somatostatin-expressing inhibitory neurons.
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Affiliation(s)
- Vijendra Sharma
- Department of Biochemistry, McGill University, Montréal, Québec, Canada.
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.
| | - Rapita Sood
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | | | - Mohammad Javad Eslamizade
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
| | - Tzu-Yu Hung
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Danning Lou
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | | | - Maya Lalzar
- Bioinformatics Services Unit, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa, Israel
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Matthew P Stokes
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | - Noah Cohen
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Alissa J Nelson
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | - Kathryn Abell
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | | | | | - Vinh T Truong
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Peng Wang
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Adonis Yiannakas
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Fatemeh Saffarzadeh
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Karim Nader
- Department of Psychology, McGill University, Montréal, Québec, Canada
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA, USA
| | | | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - Albert Quintana
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Neuroscience Institute, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Elisenda Sanz
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Neuroscience Institute, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Arkady Khoutorsky
- Department of Anesthesia, McGill University, Montréal, Québec, Canada
- Faculty of Dentistry, McGill University, Montréal, Québec, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
- Centre for Interdisciplinary Research on Brain and Learning, University of Montréal, Montréal, Québec, Canada
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.
- Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel.
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal, Québec, Canada.
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.
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Kozachuk MS, Sham TK, Martin RR, Nelson AJ, Coulthard I. Eyeing the past: synchrotron µ-XANES and XRF imaging of tarnish distribution on 19th century daguerreotypes. J Synchrotron Radiat 2019; 26:1679-1686. [PMID: 31490159 DOI: 10.1107/s1600577519006313] [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] [Received: 02/07/2019] [Accepted: 05/03/2019] [Indexed: 06/10/2023]
Abstract
Louis-Jacques-Mandé Daguerre introduced the first successful photographic process, the daguerreotype, in 1839. Tarnished regions on daguerreotypes supplied by the National Gallery of Canada were examined using scanning electron microscopy energy-dispersive X-ray spectroscopy and synchrotron-radiation analysis. Synchrotron X-ray fluorescence imaging visualized the distribution of sulfur and chlorine, two primary tarnish contributors, and showed that they were associated with the distribution of image particles on the surface. X-ray absorption near-edge structure spectroscopy determined the tarnish to be primarily composed of AgCl and Ag2S. Au2S, Au2SO4, HAuCl4 and HgSO4 were also observed to be minor contributors. Environmental contamination may be a source of these degradation compounds. Implications of these findings will be discussed.
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Affiliation(s)
- M S Kozachuk
- The Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - T K Sham
- The Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - R R Martin
- The Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - A J Nelson
- The Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - I Coulthard
- Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
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11
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Asmussen MJ, Bailey AZ, Nelson AJ. Cortical and corticospinal output modulations during reaching movements with varying directions and magnitudes of interaction torques. Neuroscience 2015; 311:268-83. [PMID: 26525892 DOI: 10.1016/j.neuroscience.2015.10.032] [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: 09/11/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
Abstract
The neural command required to coordinate a multi-joint movement is inherently complex. During multi-joint movement of the limb, the force created from movement at one joint may create a torque at a second joint known as an interaction torque. Interaction torques may be assistive or resistive thereby aiding or opposing the motion of the second joint, respectively. For movement to be effectively controlled, the central nervous system should modulate neural output to the muscles to appropriately account for interaction torques. The present study examined the neural output from the primary motor cortex before and during reaching movements that required different combinations of assistive and resistive interaction torques occurring at the shoulder and elbow joints. Using transcranial magnetic stimulation to probe neural output from the primary motor cortex, results indicate that corticospinal output controlling the upper arm is related to resistive interaction torques occurring at the shoulder joint. Further, cortical output to bi-articular muscles is associated with interaction torque and this may be driven by the fact that these muscles are in an advantageous position to control torques produced between inter-connection segments. Humans have a tendency to avoid reaching movements that involve resistive interaction torques and this may be driven by the requirement of increased neural output associated with these movements.
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Affiliation(s)
- M J Asmussen
- Department of Kinesiology, McMaster University, Hamilton L8S 4K1, Canada.
| | - A Z Bailey
- Department of Kinesiology, McMaster University, Hamilton L8S 4K1, Canada.
| | - A J Nelson
- Department of Kinesiology, McMaster University, Hamilton L8S 4K1, Canada.
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12
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Crowhurst JC, Jeffries JR, Åberg D, Zaug JM, Dai ZR, Siekhaus WJ, Teslich NE, Holliday KS, Knight KB, Nelson AJ, Hutcheon ID. A combined theoretical and experimental investigation of uranium dioxide under high static pressure. J Phys Condens Matter 2015; 27:265401. [PMID: 26053594 DOI: 10.1088/0953-8984/27/26/265401] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination of experimental and theoretical techniques. We have made Raman spectroscopic measurements up to 87 GPa, electrical transport measurements up to 50 GPa from 10 K to room temperature, and optical transmission measurements up to 28 GPa. We have also carried out theoretical calculations within the GGA + U framework. We find that Raman frequencies match to a large extent, theoretical predictions for the cotunnite (Pnma) structure above 30 GPa, but at higher pressures some behavior is not captured theoretically. The Raman measurements also imply that the low-pressure fluorite phase coexists with the cotunnite phase up to high pressures, consistent with earlier reports. Electrical transport measurements show that the resistivity decreases by more than six orders of magnitude with increasing pressure up to 50 GPa but that the material never adopts archetypal metallic behavior. Optical transmission spectra show that while UO2 becomes increasingly opaque with increasing pressure, a likely direct optical band gap of more than 1 eV exists up to at least 28 GPa. Together with the electrical transport measurements, we conclude that the high pressure electrical conductivity of UO2 is mediated by variable-range hopping.
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Affiliation(s)
- J C Crowhurst
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA 94551, USA
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13
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Styron JD, Cooper GW, Ruiz CL, Hahn KD, Chandler GA, Nelson AJ, Torres JA, McWatters BR, Carpenter K, Bonura MA. Predicting the sensitivity of the beryllium/scintillator layer neutron detector using Monte Carlo and experimental response functions. Rev Sci Instrum 2014; 85:11E617. [PMID: 25430363 DOI: 10.1063/1.4896176] [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: 06/04/2023]
Abstract
A methodology for obtaining empirical curves relating absolute measured scintillation light output to beta energy deposited is presented. Output signals were measured from thin plastic scintillator using NIST traceable beta and gamma sources and MCNP5 was used to model the energy deposition from each source. Combining the experimental and calculated results gives the desired empirical relationships. To validate, the sensitivity of a beryllium/scintillator-layer neutron activation detector was predicted and then exposed to a known neutron fluence from a Deuterium-Deuterium fusion plasma (DD). The predicted and the measured sensitivity were in statistical agreement.
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Affiliation(s)
- J D Styron
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - G W Cooper
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - C L Ruiz
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - K D Hahn
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - G A Chandler
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - A J Nelson
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - J A Torres
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - B R McWatters
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Ken Carpenter
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - M A Bonura
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
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14
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Bonura MA, Ruiz CL, Fehl DL, Cooper GW, Chandler G, Hahn KD, Nelson AJ, Styron JD, Torres JA. A technique for verifying the input response function of neutron time-of-flight scintillation detectors using cosmic rays. Rev Sci Instrum 2014; 85:11D633. [PMID: 25430209 DOI: 10.1063/1.4896958] [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: 06/04/2023]
Abstract
An accurate interpretation of DD or DT fusion neutron time-of-flight (nTOF) signals from current mode detectors employed at the Z-facility at Sandia National Laboratories requires that the instrument response functions (IRF's) be deconvolved from the measured nTOF signals. A calibration facility that produces detectable sub-ns radiation pulses is typically used to measure the IRF of such detectors. This work, however, reports on a simple method that utilizes cosmic radiation to measure the IRF of nTOF detectors, operated in pulse-counting mode. The characterizing metrics reported here are the throughput delay and full-width-at-half-maximum. This simple approach yields consistent IRF results with the same detectors calibrated in 2007 at a LINAC bremsstrahlung accelerator (Idaho State University). In particular, the IRF metrics from these two approaches and their dependence on the photomultipliers bias agree to within a few per cent. This information may thus be used to verify if the IRF for a given nTOF detector employed at Z has changed since its original current-mode calibration and warrants re-measurement.
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Affiliation(s)
- M A Bonura
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - C L Ruiz
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA
| | - D L Fehl
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA
| | - G W Cooper
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - G Chandler
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA
| | - K D Hahn
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA
| | - A J Nelson
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - J D Styron
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - J A Torres
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA
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Hahn KD, Cooper GW, Ruiz CL, Fehl DL, Chandler GA, Knapp PF, Leeper RJ, Nelson AJ, Smelser RM, Torres JA. Fusion-neutron-yield, activation measurements at the Z accelerator: design, analysis, and sensitivity. Rev Sci Instrum 2014; 85:043507. [PMID: 24784607 DOI: 10.1063/1.4870779] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r(2) decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm(2) and is ∼ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects.
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Affiliation(s)
- K D Hahn
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - G W Cooper
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - C L Ruiz
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - D L Fehl
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - G A Chandler
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - P F Knapp
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - R J Leeper
- Los Alamos National Laboratories, Plasma Physics Group, Los Alamos, New Mexico 87545, USA
| | - A J Nelson
- Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - R M Smelser
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
| | - J A Torres
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87123, USA
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Abstract
Resolution describes the smallest details within a sample that can be recovered by a microscope lens system. For optical microscopes detecting visible light, diffraction limits the resolution to ∼200-250 nm. In contrast, localization measures the position of an isolated object using its image. Single fluorescent molecules can be localized with an uncertainty of a few tens of nanometres, and in some cases less than one nanometre. Superresolution fluorescence localization microscopy (SRFLM) images and localizes fluorescent molecules in a sample. By controlling the visibility of the fluorescent molecules with light, it is possible to cause a sparse subset of the tags to fluoresce and be spatially separated from each other. A movie is acquired with a camera, capturing images of many sets of visible fluorescent tags over a period of time. The movie is then analysed by a computer whereby all of the single molecules are independently measured, and their positions are recorded. When the coordinates of a sufficient number of molecules are collected, an image can be rendered by plotting the coordinates of the localized molecules. The spatial resolution of these rendered images can be better than 20 nm, roughly an order of magnitude better than the diffraction limited resolution. The invention of SRFLM has led to an explosion of related techniques. Through the use of specialized optics, the fluorescent signal can be split into multiple detection channels. These channels can capture additional information such as colour (emission wavelength), orientation and three-dimensional position of the detected molecules. Measurement of the colour of the detected fluorescence can allow researchers to distinguish multiple types of fluorescent tags and to study the interaction between multiple molecules of interest. Three-dimensional imaging and determination of molecular orientations offer insight into structural organization of the sample. SRFLM is compatible with living samples and has helped to illuminate many dynamic biological processes, such as the trajectories of molecules within living cells. This review discusses the concept and process of SRFLM imaging and investigates recent advances in SRFLM functionality. Since its announcement in 2006, SRFLM has been quickly adopted and modified by many researchers to help investigate questions whose answers lie below the diffraction limit. The versatility of the SRFLM technique has great promise for improving our understanding of cell biology at the molecular level.
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Affiliation(s)
- A J Nelson
- Department of Physics and Astronomy and Institute for Molecular Biophysics, University of Maine, Orono, Maine, U.S.A
| | - S T Hess
- Department of Physics and Astronomy and Institute for Molecular Biophysics, University of Maine, Orono, Maine, U.S.A
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Richardson JD, Bertaso AG, Frost L, Psaltis PJ, Carbone A, Koschade B, Wong DT, Nelson AJ, Paton S, Williams K, Azarisman S, Worthley MI, Teo KS, Gronthos S, Zannettino ACW, Worthley SG. Cardiac magnetic resonance, transthoracic and transoesophageal echocardiography: a comparison of in vivo assessment of ventricular function in rats. Lab Anim 2013; 47:291-300. [PMID: 23836849 DOI: 10.1177/0023677213494373] [Citation(s) in RCA: 7] [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] [Indexed: 11/15/2022]
Abstract
In vivo assessment of ventricular function in rodents has largely been restricted to transthoracic echocardiography (TTE). However 1.5 T cardiac magnetic resonance (CMR) and transoesophageal echocardiography (TOE) have emerged as possible alternatives. Yet, to date, no study has systematically assessed these three imaging modalities in determining ejection fraction (EF) in rats. Twenty rats underwent imaging four weeks after surgically-induced myocardial infarction. CMR was performed on a 1.5 T scanner, TTE was conducted using a 9.2 MHz transducer and TOE was performed with a 10 MHz intracardiac echo catheter. Correlation between the three techniques for EF determination and analysis reproducibility was assessed. Moderate-strong correlation was observed between the three modalities; the greatest between CMR and TOE (intraclass correlation coefficient (ICC) = 0.89), followed by TOE and TTE (ICC = 0.70) and CMR and TTE (ICC = 0.63). Intra- and inter-observer variations were excellent with CMR (ICC = 0.99 and 0.98 respectively), very good with TTE (0.90 and 0.89) and TOE (0.87 and 0.84). Each modality is a viable option for evaluating ventricular function in rats, however the high image quality and excellent reproducibility of CMR offers distinct advantages even at 1.5 T with conventional coils and software.
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Affiliation(s)
- J D Richardson
- Cardiovascular Research Centre, Royal Adelaide Hospital and Department of Medicine, University of Adelaide, South Australia, Australia
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18
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Duncan RF, Dundon BK, Nelson AJ, Williams K, Carbone A, Worthley MI, Zaman A, Worthley SG. 1029“MRI phase-encoded tissue velocity mapping for the
non-invasive estimation of left ventricular diastolic filling pressure: A
MRI-cardiac catheterisation comparison study”. Eur Heart J Cardiovasc Imaging 2013. [DOI: 10.1093/ehjci/jet070ab] [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: 11/14/2022] Open
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19
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Ruiz CL, Chandler GA, Cooper GW, Fehl DL, Hahn KD, Leeper RJ, McWatters BR, Nelson AJ, Smelser RM, Snow CS, Torres JA. Progress in obtaining an absolute calibration of a total deuterium-tritium neutron yield diagnostic based on copper activation. Rev Sci Instrum 2012; 83:10D913. [PMID: 23126916 DOI: 10.1063/1.4729495] [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: 06/01/2023]
Abstract
The 350-keV Cockroft-Walton accelerator at Sandia National laboratory's Ion Beam facility is being used to calibrate absolutely a total DT neutron yield diagnostic based on the (63)Cu(n,2n)(62)Cu(β+) reaction. These investigations have led to first-order uncertainties approaching 5% or better. The experiments employ the associated-particle technique. Deuterons at 175 keV impinge a 2.6 μm thick erbium tritide target producing 14.1 MeV neutrons from the T(d,n)(4)He reaction. The alpha particles emitted are measured at two angles relative to the beam direction and used to infer the neutron flux on a copper sample. The induced (62)Cu activity is then measured and related to the neutron flux. This method is known as the F-factor technique. Description of the associated-particle method, copper sample geometries employed, and the present estimates of the uncertainties to the F-factor obtained are given.
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Affiliation(s)
- C L Ruiz
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
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Gatu Johnson M, Frenje JA, Casey DT, Li CK, Séguin FH, Petrasso R, Ashabranner R, Bionta RM, Bleuel DL, Bond EJ, Caggiano JA, Carpenter A, Cerjan CJ, Clancy TJ, Doeppner T, Eckart MJ, Edwards MJ, Friedrich S, Glenzer SH, Haan SW, Hartouni EP, Hatarik R, Hatchett SP, Jones OS, Kyrala G, Le Pape S, Lerche RA, Landen OL, Ma T, MacKinnon AJ, McKernan MA, Moran MJ, Moses E, Munro DH, McNaney J, Park HS, Ralph J, Remington B, Rygg JR, Sepke SM, Smalyuk V, Spears B, Springer PT, Yeamans CB, Farrell M, Jasion D, Kilkenny JD, Nikroo A, Paguio R, Knauer JP, Glebov VY, Sangster TC, Betti R, Stoeckl C, Magoon J, Shoup MJ, Grim GP, Kline J, Morgan GL, Murphy TJ, Leeper RJ, Ruiz CL, Cooper GW, Nelson AJ. Neutron spectrometry--an essential tool for diagnosing implosions at the National Ignition Facility (invited). Rev Sci Instrum 2012; 83:10D308. [PMID: 23126835 DOI: 10.1063/1.4728095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured neutron spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at the National Ignition Facility (NIF). A suite of neutron-time-of-flight (nTOF) spectrometers and a magnetic recoil spectrometer (MRS) have been implemented in different locations around the NIF target chamber, providing good implosion coverage and the complementarity required for reliable measurements of Y(n), T(i), and dsr. From the measured dsr value, an areal density (ρR) is determined through the relationship ρR(tot) (g∕cm(2)) = (20.4 ± 0.6) × dsr(10-12 MeV). The proportionality constant is determined considering implosion geometry, neutron attenuation, and energy range used for the dsr measurement. To ensure high accuracy in the measurements, a series of commissioning experiments using exploding pushers have been used for in situ calibration of the as-built spectrometers, which are now performing to the required accuracy. Recent data obtained with the MRS and nTOFs indicate that the implosion performance of cryogenically layered DT implosions, characterized by the experimental ignition threshold factor (ITFx), which is a function of dsr (or fuel ρR) and Y(n), has improved almost two orders of magnitude since the first shot in September, 2010.
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Affiliation(s)
- M Gatu Johnson
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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21
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Nelson AJ, Ruiz CL, Cooper GW, Chandler GA, Fehl DL, Hahn KD, Leeper RJ, Smelser R, Torres JA. A novel method for modeling the neutron time of flight detector response in current mode to inertial confinement fusion experiments (invited). Rev Sci Instrum 2012; 83:10D915. [PMID: 23126918 DOI: 10.1063/1.4742140] [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: 06/01/2023]
Abstract
A novel method for modeling the neutron time of flight (nTOF) detector response in current mode for inertial confinement fusion experiments has been applied to the on-axis nTOF detectors located in the basement of the Z-Facility. It will be shown that this method can identify sources of neutron scattering, and is useful for predicting detector responses in future experimental configurations, and for identifying potential sources of neutron scattering when experimental set-ups change. This method can also provide insight on how much broadening neutron scattering contributes to the primary signals, which is then subtracted from them. Detector time responses are deconvolved from the signals, allowing a transformation from dN/dt to dN/dE, extracting neutron spectra at each detector location; these spectra are proportional to the absolute yield.
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Affiliation(s)
- A J Nelson
- Department of Chemical & Nuclear Engineering, University of New Mexico, Albuquerque, 87131, USA.
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22
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Cooper GW, Ruiz CL, Leeper RJ, Chandler GA, Hahn KD, Nelson AJ, Torres JA, Smelser RM, McWatters BR, Bleuel DL, Yeamans CB, Knittel KM, Casey DT, Frenje JA, Gatu Johnson M, Petrasso RD, Styron JD. Copper activation deuterium-tritium neutron yield measurements at the National Ignition Facility. Rev Sci Instrum 2012; 83:10D918. [PMID: 23126920 DOI: 10.1063/1.4746999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A DT neutron yield diagnostic based on the reactions, (63)Cu(n,2n)(62)Cu(β(+)) and (65)Cu(n,2n)( 64) Cu(β(+)), has been fielded at the National Ignition Facility (NIF). The induced copper activity is measured using a NaI γ-γ coincidence system. Uncertainties in the 14-MeV DT yield measurements are on the order of 7% to 8%. In addition to measuring yield, the ratio of activities induced in two, well-separated copper samples are used to measure the relative anisotropy of the fuel ρR to uncertainties as low as 5%.
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Affiliation(s)
- G W Cooper
- Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, 87131, USA.
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Casey DT, Frenje JA, Gatu Johnson M, Séguin FH, Li CK, Petrasso RD, Glebov VY, Katz J, Knauer JP, Meyerhofer DD, Sangster TC, Bionta RM, Bleuel DL, Döppner T, Glenzer S, Hartouni E, Hatchett SP, Le Pape S, Ma T, MacKinnon A, McKernan MA, Moran M, Moses E, Park HS, Ralph J, Remington BA, Smalyuk V, Yeamans CB, Kline J, Kyrala G, Chandler GA, Leeper RJ, Ruiz CL, Cooper GW, Nelson AJ, Fletcher K, Kilkenny J, Farrell M, Jasion D, Paguio R. Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF. Rev Sci Instrum 2012; 83:10D912. [PMID: 23126915 DOI: 10.1063/1.4738657] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.
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Affiliation(s)
- D T Casey
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA.
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24
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Hahn KD, Ruiz CL, Cooper GW, Nelson AJ, Chandler GA, Leeper RJ, McWatters BR, Smelser RM, Torres JA. Calibration of neutron-yield diagnostics in attenuating and scattering environments. Rev Sci Instrum 2012; 83:10D914. [PMID: 23126917 DOI: 10.1063/1.4732067] [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: 06/01/2023]
Abstract
We have performed absolute calibrations of a fusion-neutron-yield copper-activation diagnostic in environments that significantly attenuate and scatter neutrons. We have measured attenuation and scattering effects and have compared the measurements to Monte Carlo simulations using the Monte Carlo N-Particle code. We find that measurements and simulations are consistent within 10%.
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Affiliation(s)
- K D Hahn
- Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111, USA.
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25
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Rai N, Premji A, Tommerdahl M, Nelson AJ. Continuous theta-burst rTMS over primary somatosensory cortex modulates tactile perception on the hand. Clin Neurophysiol 2011; 123:1226-33. [PMID: 22100859 DOI: 10.1016/j.clinph.2011.09.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/21/2011] [Accepted: 09/24/2011] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Theta-burst stimulation (TBS) over the primary somatosensory cortex (SI) alters cortical excitability, and in its intermittent form (iTBS) improves tactile spatial acuity. The effects of continuous TBS (cTBS) on tactile acuity remain unknown. The present study examined the influence of cTBS over SI on temporal and spatial tactile acuity on the contralateral hand. METHODS In separate experiments, temporal discrimination threshold (TDT) and spatial amplitude discrimination threshold (SDT) were obtained from the right hand before and for up to 34 min following real and sham cTBS (600 pulses) over left-hemisphere SI. RESULTS CTBS reduced temporal and spatial tactile acuity for up to 18 min following real cTBS. Tactile acuity was unaltered in the groups receiving sham cTBS. CONCLUSIONS CTBS over SI impairs both temporal and spatial domains of tactile acuity for a similar duration. SIGNIFICANCE CTBS over SI appears to decrease neural activity within targeted cortex and has potential utility in reducing excessive sensory processing.
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Affiliation(s)
- N Rai
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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26
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Richardson JD, Nelson AJ, Worthley SG, Teo KSL, Baillie T, Worthley MI. Multivessel coronary artery spasm. Heart Lung Circ 2011; 21:113-6. [PMID: 21852191 DOI: 10.1016/j.hlc.2011.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/22/2011] [Indexed: 11/29/2022]
Abstract
Coronary spasm is increasingly recognised as an important aetiological mechanism causing myocardial ischaemia. Occasionally cases present with evidence of ST segment elevation myocardial infarction, usually secondary to spasm confined to a solitary coronary artery. We present the rare and life-threatening case of severe coronary spasm afflicting all three major epicardial arteries simultaneously. It describes the difficult emergency scenario and ongoing management dilemmas encountered by physicians confronted with multivessel coronary spasm. Moreover we discuss the malignant prognosis associated with this ailment and describe the potential insights provided by cardiac magnetic resonance imaging that might identify those at greatest risk after the index event.
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Affiliation(s)
- J D Richardson
- Cardiovascular Research Centre, Royal Adelaide Hospital, Australia
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27
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Cho BI, Engelhorn K, Correa AA, Ogitsu T, Weber CP, Lee HJ, Feng J, Ni PA, Ping Y, Nelson AJ, Prendergast D, Lee RW, Falcone RW, Heimann PA. Electronic structure of warm dense copper studied by ultrafast x-ray absorption spectroscopy. Phys Rev Lett 2011; 106:167601. [PMID: 21599412 DOI: 10.1103/physrevlett.106.167601] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 02/21/2011] [Indexed: 05/30/2023]
Abstract
We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is necessary.
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Affiliation(s)
- B I Cho
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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28
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Galtier E, Rosmej FB, Dzelzainis T, Riley D, Khattak FY, Heimann P, Lee RW, Nelson AJ, Vinko SM, Whitcher T, Wark JS, Tschentscher T, Toleikis S, Fäustlin RR, Sobierajski R, Jurek M, Juha L, Chalupsky J, Hajkova V, Kozlova M, Krzywinski J, Nagler B. Decay of cystalline order and equilibration during the solid-to-plasma transition induced by 20-fs microfocused 92-eV free-electron-laser pulses. Phys Rev Lett 2011; 106:164801. [PMID: 21599370 DOI: 10.1103/physrevlett.106.164801] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Indexed: 05/30/2023]
Abstract
We have studied a solid-to-plasma transition by irradiating Al foils with the FLASH free electron laser at intensities up to 10(16) W/cm(2). Intense XUV self-emission shows spectral features that are consistent with emission from regions of high density, which go beyond single inner-shell photoionization of solids. Characteristic features of intrashell transitions allowed us to identify Auger heating of the electrons in the conduction band occurring immediately after the absorption of the XUV laser energy as the dominant mechanism. A simple model of a multicharge state inverse Auger effect is proposed to explain the target emission when the conduction band at solid density becomes more atomiclike as energy is transferred from the electrons to the ions. This allows one to determine, independent of plasma simulations, the electron temperature and density just after the decay of crystalline order and to characterize the early time evolution.
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Affiliation(s)
- E Galtier
- Sorbonne Universités, Pierre et Marie Curie, UMR 7605, LULI, Paris, France
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29
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Pedersoli E, Capotondi F, Cocco D, Zangrando M, Kaulich B, Menk RH, Locatelli A, Mentes TO, Spezzani C, Sandrin G, Bacescu DM, Kiskinova M, Bajt S, Barthelmess M, Barty A, Schulz J, Gumprecht L, Chapman HN, Nelson AJ, Frank M, Pivovaroff MJ, Woods BW, Bogan MJ, Hajdu J. Multipurpose modular experimental station for the DiProI beamline of Fermi@Elettra free electron laser. Rev Sci Instrum 2011; 82:043711. [PMID: 21529017 DOI: 10.1063/1.3582155] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a compact modular apparatus with a flexible design that will be operated at the DiProI beamline of the Fermi@Elettra free electron laser (FEL) for performing static and time-resolved coherent diffraction imaging experiments, taking advantage of the full coherence and variable polarization of the short seeded FEL pulses. The apparatus has been assembled and the potential of the experimental setup is demonstrated by commissioning tests with coherent synchrotron radiation. This multipurpose experimental station will be open to general users after installation at the Fermi@Elettra free electron laser in 2011.
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Affiliation(s)
- Emanuele Pedersoli
- Fermi, Elettra Sincrotrone Trieste, SS 14 - km 163.5, 34149 Basovizza, Trieste, Italy
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Andreasson J, Iwan B, Andrejczuk A, Abreu E, Bergh M, Caleman C, Nelson AJ, Bajt S, Chalupsky J, Chapman HN, Fäustlin RR, Hajkova V, Heimann PA, Hjörvarsson B, Juha L, Klinger D, Krzywinski J, Nagler B, Pálsson GK, Singer W, Seibert MM, Sobierajski R, Toleikis S, Tschentscher T, Vinko SM, Lee RW, Hajdu J, Tîmneanu N. Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 83:016403. [PMID: 21405780 DOI: 10.1103/physreve.83.016403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 11/25/2010] [Indexed: 05/30/2023]
Abstract
Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 10(17) W/cm(2) were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 10(16) W/cm(2). This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.
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Affiliation(s)
- J Andreasson
- Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124 Uppsala, Sweden
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Abstract
OBJECTIVES Reduced cortical inhibition is a feature of focal hand dystonia and this likely contributes to excessive muscle contractions. Inhibition from the opposite hemisphere, known as interhemispheric inhibition (IHI), was studied bidirectionally in 7 right-handed patients with writer's cramp (WC) and age-matched healthy controls in a cross-sectional physiologic study. METHODS IHI was measured with paired transcranial magnetic stimulation with the conditioning stimulus applied to the motor cortex and the test stimulus applied to the contralateral motor cortex. Surface EMG was measured in right and left first dorsal interosseous muscles during rest, and while holding a pen between the thumb and index finger at 20% maximum voluntary contraction with the right dystonia-affected hand. The time course and magnitude of IHI was studied at interstimulus intervals of 6, 8, 10, 12, 30, 40, and 50 msec between the conditioning stimulus and test stimulus. RESULTS In WC at rest, IHI was significantly reduced in the dystonia-affected right hand (IHI from right to left motor cortex) at both short (SIHI, 10-12 msec) and long (LIHI, 30-40 msec) intervals compared to the unaffected hand. Compared to controls, SIHI and LIHI were reduced in the dystonia-affected hand only. There was no difference in IHI between controls and WC during the task of holding a pen. CONCLUSIONS In WC, both SIHI and LIHI are reduced in the dystonia-affected hand compared to the unaffected hand and to healthy controls. Impaired IHI may contribute to excessive muscle contraction in WC.
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Affiliation(s)
- A J Nelson
- Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
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32
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Vinko SM, Zastrau U, Mazevet S, Andreasson J, Bajt S, Burian T, Chalupsky J, Chapman HN, Cihelka J, Doria D, Döppner T, Düsterer S, Dzelzainis T, Fäustlin RR, Fortmann C, Förster E, Galtier E, Glenzer SH, Göde S, Gregori G, Hajdu J, Hajkova V, Heimann PA, Irsig R, Juha L, Jurek M, Krzywinski J, Laarmann T, Lee HJ, Lee RW, Li B, Meiwes-Broer KH, Mithen JP, Nagler B, Nelson AJ, Przystawik A, Redmer R, Riley D, Rosmej F, Sobierajski R, Tavella F, Thiele R, Tiggesbäumker J, Toleikis S, Tschentscher T, Vysin L, Whitcher TJ, White S, Wark JS. Electronic structure of an XUV photogenerated solid-density aluminum plasma. Phys Rev Lett 2010; 104:225001. [PMID: 20867176 DOI: 10.1103/physrevlett.104.225001] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Indexed: 05/29/2023]
Abstract
By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.
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Affiliation(s)
- S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
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Martin RR, Naftel SJ, Nelson AJ, Edwards M, Mithoowani H, Stakiw J. Synchrotron radiation analysis of possible correlations between metal status in human cementum and periodontal disease. J Synchrotron Radiat 2010; 17:263-267. [PMID: 20157281 DOI: 10.1107/s0909049509052807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Accepted: 12/08/2009] [Indexed: 05/28/2023]
Abstract
Periodontitis is a serious disease that affects up to 50% of an adult population. It is a chronic condition involving inflammation of the periodontal ligament and associated tissues leading to eventual tooth loss. Some evidence suggests that trace metals, especially zinc and copper, may be involved in the onset and severity of periodontitis. Thus we have used synchrotron X-ray fluorescence imaging on cross sections of diseased and healthy teeth using a microbeam to explore the distribution of trace metals in cementum and adhering plaque. The comparison between diseased and healthy teeth indicates that there are elevated levels of zinc, copper and nickel in diseased teeth as opposed to healthy teeth. This preliminary correlation between elevated levels of trace metals in the cementum and plaque of diseased teeth suggests that metals may play a role in the progress of periodontitis.
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Affiliation(s)
- R R Martin
- Department of Chemistry, University of Western Ontario, London, Canada.
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34
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Nelson AJ, Toleikis S, Chapman H, Bajt S, Krzywinski J, Chalupsky J, Juha L, Cihelka J, Hajkova V, Vysin L, Burian T, Kozlova M, Fäustlin RR, Nagler B, Vinko SM, Whitcher T, Dzelzainis T, Renner O, Saksl K, Khorsand AR, Heimann PA, Sobierajski R, Klinger D, Jurek M, Pelka J, Iwan B, Andreasson J, Timneanu N, Fajardo M, Wark JS, Riley D, Tschentscher T, Hajdu J, Lee RW. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions. Opt Express 2009; 17:18271-8. [PMID: 19907618 DOI: 10.1364/oe.17.018271] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 microJ, 5 Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) - PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of < or =1 microm. Observations were correlated with simulations of best focus to provide further relevant information.
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Affiliation(s)
- A J Nelson
- LawrenceLivermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
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35
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Chao TI, Xiang S, Chen CS, Chin WC, Nelson AJ, Wang C, Lu J. Carbon nanotubes promote neuron differentiation from human embryonic stem cells. Biochem Biophys Res Commun 2009; 384:426-30. [PMID: 19426708 DOI: 10.1016/j.bbrc.2009.04.157] [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] [Received: 04/23/2009] [Accepted: 04/28/2009] [Indexed: 10/20/2022]
Abstract
Human embryonic stem cells (hESCs) hold great promise for regenerative medicine and transplantation therapy due to their self-renewal and pluripotent properties. We report that 2D thin film scaffolds composed of biocompatible polymer grafted carbon nanotubes (CNTs), can selectively differentiate human embryonic stem cells into neuron cells while maintaining excellent cell viability. According to fluorescence image analysis, neuron differentiation efficiency of poly(acrylic acid) grafted CNT thin films is significant greater than that on poly(acrylic acid) thin films. When compared with the conventional poly-L-ornithine surfaces, a standard substratum commonly used for neuron culture, this new type thin film scaffold shows enhanced neuron differentiation. No noticeable cytotoxic effect difference has been detected between these two surfaces. The surface analysis and cell adhesion study have suggested that CNT-based surfaces can enhance protein adsorption and cell attachment. This finding indicates that CNT-based materials are excellent candidates for hESCs' neuron differentiation.
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Affiliation(s)
- Tzu-I Chao
- School of Engineering, University of California, 5200 North Lake Road, UC Merced, Merced, CA 95343, USA
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36
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Leeper RJ, Ruiz CL, Chandler GA, Cooper GW, Bower DE, Fittinghoff DN, Hagen EC, Hollaway JR, McKenna IJ, McPherson LA, May MJ, Meeham BT, Nelson AJ, Perry TS, Porter JL, Robbins LL, Sinars DB, Torres JA, Ziegler LH. ZR neutron diagnostic suite. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/112/3/032076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Lindenberg AM, Engemann S, Gaffney KJ, Sokolowski-Tinten K, Larsson J, Hillyard PB, Reis DA, Fritz DM, Arthur J, Akre RA, George MJ, Deb A, Bucksbaum PH, Hajdu J, Meyer DA, Nicoul M, Blome C, Tschentscher T, Cavalieri AL, Falcone RW, Lee SH, Pahl R, Rudati J, Fuoss PH, Nelson AJ, Krejcik P, Siddons DP, Lorazo P, Hastings JB. X-ray diffuse scattering measurements of nucleation dynamics at femtosecond resolution. Phys Rev Lett 2008; 100:135502. [PMID: 18517965 DOI: 10.1103/physrevlett.100.135502] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Indexed: 05/26/2023]
Abstract
Femtosecond time-resolved small and wide angle x-ray diffuse scattering techniques are applied to investigate the ultrafast nucleation processes that occur during the ablation process in semiconducting materials. Following intense optical excitation, a transient liquid state of high compressibility characterized by large-amplitude density fluctuations is observed and the buildup of these fluctuations is measured in real time. Small-angle scattering measurements reveal snapshots of the spontaneous nucleation of nanoscale voids within a metastable liquid and support theoretical predictions of the ablation process.
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Affiliation(s)
- A M Lindenberg
- PULSE Center, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA
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Becker M, Rothman J, Nelson AJ, Freedland R, Garcia D, Feit L, Barth J, Sabini R. The effects of multifocal refractive lenses on occipital extension and forward head posture during a visual task. Ergonomics 2007; 50:2095-103. [PMID: 17852377 DOI: 10.1080/00140130701419166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The purpose of this study was to determine if a change in forward head posture and occipital extension occurred in participants who wore multifocal lenses vs. those persons with non-multifocal lenses while performing an 8-min visual reading task on a visual display unit (VDU). Forty-two healthy human participants were recruited for this study. Thirty-three participants completed the study. Fourteen participants wore multifocal lenses and 19 wore frames with non-multifocal lenses. To evaluate the degree of change of forward head posture and occipital extension digital photographs of cervical posture were taken at four different time intervals: prior to performing the reading task and at 3, 5 and 8 min during the reading task. The digital photographs were analysed utilizing a computer program. Two one-way ANOVA were utilized to determine the degree of change of forward head posture and occipital extension between groups. A significant difference was identified between groups for changes in degrees of forward head posture while performing a visual reading task on a VDU. However, no significant difference between groups was found for occipital extension while performing the same task. Multifocal wearers exhibit greater degrees of change in forward head posture and occipital extension than non-multifocal wearers. These postural changes may place them at a greater risk for musculoskeletal disorders and headaches.
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Affiliation(s)
- M Becker
- College of Staten Island of The City University of New York, Department of Physical Therapy, 2800 Victory Boulevard, Staten Island, New York 10314, USA
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Moses B, Nelson RM, Nelson AJ, Cheifetz P. The relationship between skin temperature and neuronal characteristics in the median, ulnar and radial nerves of non-impaired individuals. Electromyogr Clin Neurophysiol 2007; 47:351-360. [PMID: 18051629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The purpose of this study was to evaluate the relationship between the nerve conduction characteristics in the median, ulnar and radial nerves and presenting skin temperature in non-impaired individuals as they were subjected to electrophysiological testing. Previous researchers artificially manipulated the skin temperature and demonstrated that there was a positive relationship between temperature and nerve conduction velocity and a negative correlation between distal latency and evoked motor action potential (EMAP). The sample population was 50 non-impaired individuals derived from a venue in the New York City and Long Island region. The independent variable was skin temperature. The dependent variables were: motor nerve conduction velocity, motor distal latency, EMAP of median and ulnar nerves, sensory distal latency and sensory nerve action potential (SNAP) of median, ulnar and radial nerves. The data were analyzed using descriptive statistics, the Bonferroni correction factor and correlation statistics. The study showed significant correlation in median motor distal latency, ulnar motor distal latency, ulnar sensory distal latency, median sensory amplitude, and ulnar sensory amplitude. The NCV, the distal latency and the amplitude of the median, ulnar and radial nerves were similar in values to other researchers' normal values.
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Affiliation(s)
- B Moses
- Electrophysiology Program, Rocky Mountain University of Health Professions, Provo, UT, USA
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Hillyard PB, Gaffney KJ, Lindenberg AM, Engemann S, Akre RA, Arthur J, Blome C, Bucksbaum PH, Cavalieri AL, Deb A, Falcone RW, Fritz DM, Fuoss PH, Hajdu J, Krejcik P, Larsson J, Lee SH, Meyer DA, Nelson AJ, Pahl R, Reis DA, Rudati J, Siddons DP, Sokolowski-Tinten K, von der Linde D, Hastings JB. Carrier-density-dependent lattice stability in InSb. Phys Rev Lett 2007; 98:125501. [PMID: 17501133 DOI: 10.1103/physrevlett.98.125501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2006] [Indexed: 05/15/2023]
Abstract
The ultrafast decay of the x-ray diffraction intensity following laser excitation of an InSb crystal has been utilized to observe carrier dependent changes in the potential energy surface. For the first time, an abrupt carrier dependent onset for potential energy surface softening and the appearance of accelerated atomic disordering for a very high average carrier density have been observed. Inertial dynamics dominate the early stages of crystal disordering for a wide range of carrier densities between the onset of crystal softening and the appearance of accelerated atomic disordering.
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Affiliation(s)
- P B Hillyard
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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Fritz DM, Reis DA, Adams B, Akre RA, Arthur J, Blome C, Bucksbaum PH, Cavalieri AL, Engemann S, Fahy S, Falcone RW, Fuoss PH, Gaffney KJ, George MJ, Hajdu J, Hertlein MP, Hillyard PB, Horn-von Hoegen M, Kammler M, Kaspar J, Kienberger R, Krejcik P, Lee SH, Lindenberg AM, McFarland B, Meyer D, Montagne T, Murray ED, Nelson AJ, Nicoul M, Pahl R, Rudati J, Schlarb H, Siddons DP, Sokolowski-Tinten K, Tschentscher T, von der Linde D, Hastings JB. Ultrafast bond softening in bismuth: mapping a solid's interatomic potential with X-rays. Science 2007; 315:633-6. [PMID: 17272718 DOI: 10.1126/science.1135009] [Citation(s) in RCA: 133] [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: 11/02/2022]
Abstract
Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.
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Affiliation(s)
- D M Fritz
- Frontiers in Optical Coherent and Ultrafast Science (FOCUS) Center, Departments of Physics and Applied Physics Program, University of Michigan, Ann Arbor, MI 48109, USA.
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Crowhurst JC, Goncharov AF, Sadigh B, Evans CL, Morrall PG, Ferreira JL, Nelson AJ. Synthesis and Characterization of the Nitrides of Platinum and Iridium. Science 2006; 311:1275-8. [PMID: 16513980 DOI: 10.1126/science.1121813] [Citation(s) in RCA: 442] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Transition metal nitrides are of great technological and fundamental importance because of their strength and durability and because of their useful optical, electronic, and magnetic properties. We have evaluated a recently synthesized platinum nitride (PtN) that was shown to have a large bulk modulus, and we propose a structure that is isostructural with pyrite and has the stoichiometry PtN2. We have also synthesized a recoverable nitride of iridium under nearly the same conditions of pressure and temperature as PtN2. Although it has the same stoichiometry, it exhibits much lower structural symmetry. Preliminary results suggest that the bulk modulus of this material is also very large.
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Affiliation(s)
- Jonathan C Crowhurst
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551, USA.
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Nelson RM, Kaur H, Muniz E, Gasiewska E, Lugo J, Agro J, Nelson AJ, Rothman J. Neuronal conduction studies of the median nerve in non-impaired humans: a comparison of accepted techniques. Electromyogr Clin Neurophysiol 2004; 44:281-7. [PMID: 15378867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
BACKGROUND AND PURPOSE There are two commonly accepted techniques used for distal electro-stimulation placement when performing median motor nerve conduction studies. The purpose of this study was to compare latency using two commonly accepted sites of distal stimulation of the median nerve when performing motor nerve conduction studies on non-impaired adult humans. PARTICIPANTS The sample consisted of 36 non-impaired participants (15 female, 21 male) aged 20 to 40 years. METHODS Participants were randomly assigned to two groups and tested bilaterally for the median motor nerve. For distal stimulation of the median motor nerve, in the first group, 8 cm was measured from the center of the muscle diagonally to arrive at a point between the flexor carpi radialis and plamaris longus tendons. In the second group, 3.5 cm was measured from the distal wrist crease proximally along the median nerve for the distal stimulation of the median motor nerve. Distal latency of both techniques was obtained. Surface skin temperature of the palm was recorded throughout the procedures. RESULTS No significant differences were found between the 8 cm and 3.5 cm techniques at p < or = 0. 05 level. COMMENT Even though no differences were found between the two techniques, the 3.5-cm technique is recommended because of its consistency as an anatomical landmark reducing the potential for measurement error.
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Affiliation(s)
- R M Nelson
- The College of Staten Island, Program in Physical Therapy, City University of New York, 2800 Victory Blvd, Staten Island, New York 10314, USA
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Willey TM, Vance AL, van Buuren T, Bostedt C, Nelson AJ, Terminello LJ, Fadley CS. Chemically transformable configurations of mercaptohexadecanoic acid self-assembled monolayers adsorbed on Au(111). Langmuir 2004; 20:2746-2752. [PMID: 15835147 DOI: 10.1021/la036073o] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Carboxyl-terminated self-assembled monolayers (SAMs) are commonly used in a variety of applications, with the assumption that the molecules form well-ordered monolayers. In this work, near-edge X-ray absorption fine structure measurements verify that well-ordered monolayers can be formed using acetic acid in the solvent. Disordered monolayers with unbound molecules present in the film result using only ethanol. A stark reorientation occurs upon deprotonation of the end group by rinsing in a KOH solution. This reorientation of the end group is reversible with tilted-over, hydrogen-bound carboxyl groups while the carboxylate ion end groups are upright. C(1s) photoemission shows that SAMs formed and rinsed with acetic acid in ethanol have protonated end groups, while SAMs formed without acetic acid have a large fraction of carboxylate-terminated molecules.
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Affiliation(s)
- Trevor M Willey
- Department of Physics, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
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Nelson AJ, Staines WR, McIlroy WE. Tactile stimulus predictability modulates activity in a tactile-motor cortical network. Exp Brain Res 2004; 154:22-32. [PMID: 14574427 DOI: 10.1007/s00221-003-1627-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [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: 10/23/2002] [Accepted: 06/20/2003] [Indexed: 12/01/2022]
Abstract
Manipulating objects in the hand requires the continuous transformation of sensory input into appropriate motor behaviour. Using a novel vibrotactile device combined with fMRI, the cortical network associated with tactile sensorimotor transformations was investigated. Continuous tactile stimuli were delivered in a random or predictable pattern to the second digit on the right hand of all subjects. To better distinguish sensory and motor processes, subjects were instructed to make proportionate motor gripping responses with their left hand. A consistent cortical network of activation was revealed that included the supplementary motor, dorsal and ventral premotor, posterior parietal, primary and secondary somatosensory and primary motor cortex. Tracking the unpredictable versus predictable tactile stimulus led to greater delays in motor responses and to increased performance errors. Cortical effects due to stimulus predictability were observed in several components of the network, though it was most evident as increased cortical activation in frontal motor regions during tracking of unpredictable tactile stimuli. In contrast to the proposed hypotheses, primary and secondary somatosensory cortices contralateral to tactile input did not reveal enhanced responses during unpredictable tracking. Facilitation during unpredictable tracking was also observed in primary somatosensory cortex contralateral to motor responses, the receptive site for movement-related afference. The present study provides a novel and controlled approach to investigate the loci associated with tactile-motor processing and to measure the task-specific effect of stimulus predictability on network components.
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Affiliation(s)
- A J Nelson
- Sunnybrook and Women's College Health Science Center, University of Toronto, Ontario, Canada
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Kempson IM, Skinner WM, Kirkbride PK, Nelson AJ, Martin RR. Time-of-flight secondary ion mass spectrometry analysis of hair from archaeological remains. Eur J Mass Spectrom (Chichester) 2003; 9:589-97. [PMID: 15100469 DOI: 10.1255/ejms.584] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Hair from four individuals excavated from burial sites in Pacatnamu, Peru from the Moche (450-800 AD) and Lambayeque (900-1100 AD) periods was sectioned longitudinally and analysed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). An attempt was made to distinguish biogenic and diagenetic contributions to the elemental concentrations in the hair samples. Significant contamination was observed to have penetrated the hair samples from the burial environment. Results from the analyses indicate that the burial environment plays an important role in the postmortem variation in elemental content of hair samples. Various elements demonstrated an ability to permeate through the hair matrix over time. In addition, NaCl and what are believed to be aluminosilicates and mineral sulphates, were observed to have accumulated on the surface of the samples. Degradation of the samples was also suspected due to the presence of molecular fragments, possibly resulting from oxidation of the keratin proteins. The results should assist in the identification of reliable elemental signals in the analysis of ancient hair samples and promote caution when considering elements that are abundant in the burial environment.
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Affiliation(s)
- I M Kempson
- Ian Wark Research Institute, University of South Australia, Mawson Lakes 5095, South Australia
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Cary DR, Zaitseva NP, Gray K, O'Day KE, Darrow CB, Lane SM, Peyser TA, Satcher JH, Van Antwerp WP, Nelson AJ, Reynolds JG. Rhenium bipyridine complexes for the recognition of glucose. Inorg Chem 2002; 41:1662-9. [PMID: 11896738 DOI: 10.1021/ic010202b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bipyridine ligands containing pendant methyl, amino, and amino-boronic acid groups were synthesized. Coordination complexes of these ligands with rhenium were prepared straightforwardly and in good yield. The fluorescence behavior of the Re complexes was studied as a function of pH and exposure to various concentrations of glucose. The methyl bipyridine complex showed no change in fluorescence with pH, the amino derivative showed a rapid decrease from low pH to neutral, and the amino-boronate derivative showed little change from pH 4 to 10. Fluorescence quenching was observed at high pH as expected on the basis of a photoinduced electron transfer (PET) signaling mechanism. This behavior can be explained on the basis of the first oxidation and reduction potentials of these complexes. Glucose testing showed a significant dependence on the solvent system used. In pure methanol, the rhenium boronate complex exhibited a 55% fluorescence intensity increase upon increasing glucose concentration from 0 to 400 mg/dL. However, in 50 vol % methanol/phosphate buffered saline, none of the complexes showed significant response in the glucose range of physiological interest.
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Affiliation(s)
- Douglas R Cary
- University of California, Lawrence Livermore National Laboratory, P.O. Box 808, L-092, Livermore, California 94551, USA.
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Nelson AJ, Brooke JD, McIlroy WE, Bishop DC, Norrie RG. The gain of initial somatosensory evoked potentials alters with practice of an accurate motor task. Brain Res 2001; 890:272-9. [PMID: 11164793 DOI: 10.1016/s0006-8993(00)03136-x] [Citation(s) in RCA: 7] [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] [Indexed: 11/15/2022]
Abstract
The gain of somatosensory afferent paths from the lower limb to the cerebral cortex was investigated during the acquisition of one target location during plantar flexion. Sensory gain was measured as the magnitude of somatosensory evoked potentials (SEPs) following electrical stimulation of a peripheral nerve in the lower limb, and was recorded from the scalp. We hypothesized gain attenuation of SEPs from sensory paths serving the limb segment responsible for target acquisition. SEP gain was studied as subjects plantar flexed about the anide to a target that was 15 degrees beyond the occurrence of a cutaneous stimulus (cue) to the lateral border of the foot. The "cue" was either fixed in one location or could appear at one of three positions in space. SEP gain was tested during practice and with task acquisition. Electroencephalographic (EEG) recordings were made of primary and secondary complexes of cortical SEPs from sural and tibial nerve stimulation, with 30-40 samples averaged per subject-condition. Electromyographic (EMG) records were made of soleus muscle H-reflexes and M-waves. Target acquisition was recorded as percent correct hits. The results showed significant attenuation in sural and tibial nerve primary SEPs with task acquisition when the cue was fixed or varied in movement space (P<0.05). Secondary SEPs from tibial nerve followed this pattern. Spinal H-reflexes only attenuated with movement per se. We conclude that the CNS preferentially reduces the cerebral inflow of sensory information once such a motor task has been successfully acquired.
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Affiliation(s)
- A J Nelson
- Human Neurophysiology Laboratory, Department of Human Biology and Nutritional Science, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Abstract
OBJECTIVE To determine and compare select temporal-distance measures of stepping-in-place with gait ability in 2 age-matched groups. DESIGN Repeated measures, matched research design. SETTING Gait laboratory and hospital outpatient unit. PARTICIPANTS Convenience sample recruited from within the community and the outpatient unit of a local rehabilitation hospital included 30 healthy adults (age range, 58.1 +/- 10.8yr) and 30 age-matched adults with hemiplegia (age range, 58.6 +/- 10.3yr), secondary to a cerebrovascular accident. INTERVENTIONS Subjects were videotaped in the sagittal plane performing stepping-in-place and while walking. Select temporal-distance measures obtained by manual calculations from the video recordings were determined for 3 20-second trials of each activity. MAIN OUTCOME MEASURES Single limb support duration (SLSD) of the lower extremities (LEs) and step frequency during stepping-in-place and during gait. RESULTS A significant difference was found between the step frequency of each activity for the adults with hemiplegia (p <.05), but not for the healthy adults. A significant difference was also found between SLSD of the same LE across activities for each group (p <.05). SLSD of each LE during each individual activity, stepping-in-place, or gait, was not significantly different for the healthy adults, indicating LE symmetry; but it was significantly different for the adults with hemiplegia (p <.05), indicating LE asymmetry. CONCLUSIONS Stepping-in-place incorporates reciprocal, rhythmic LE movement patterns similar to gait. And, although SLSD of the LEs was different between the activities in both groups, each group showed similar LE movement patterns during each individual activity. In addition, step frequency was consistent between the activities for the healthy adults. These results seem to indicate that the reciprocal, rhythmic LE movement patterns, which are invoked during gait, may also be invoked during stepping-in-place. However, further research is needed to enhance the data related to stepping-in-place and gait ability in clinical populations.
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Nelson AJ, Brooke JD, McIlroy WE, Linklater CM, Staines WR. The afferent origin of the secondary somatosensory evoked potential from the lower limb in humans. Brain Res 2000; 887:432-5. [PMID: 11134636 DOI: 10.1016/s0006-8993(00)03024-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 10/18/2022]
Abstract
The afferent origin of the secondary somatosensory evoked potential elicited from stimulation of the sural and tibial nerves was investigated as the limb was cooled. It was hypothesized that the peak of this potential is initiated from primary afferents in the A alpha group. We conclude that the peak of the secondary SEP arises from an afferent source whose diameter is of similar size to that of large diameter A alpha afferents.
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Affiliation(s)
- A J Nelson
- Human Neurophysiology Laboratory, Department of Human Biology and Nutritional Science, University of Guelph, Ontario, Canada N1G 2W1.
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