70 results on '"M. Barr"'
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2. Risk of kidney disease following a pregnancy complicated by diabetes: a longitudinal, population-based data-linkage study among Aboriginal women in the Northern Territory, Australia
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Matthew J. L. Hare, Louise J. Maple-Brown, Jonathan E. Shaw, Jacqueline A. Boyle, Paul D. Lawton, Elizabeth L. M. Barr, Steven Guthridge, Vanya Webster, Denella Hampton, Gurmeet Singh, Roland F. Dyck, and Federica Barzi
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Endocrinology, Diabetes and Metabolism ,Internal Medicine - Abstract
Aims/hypothesis The aim of this work was to investigate the risk of developing chronic kidney disease (CKD) or end-stage kidney disease (ESKD) following a pregnancy complicated by gestational diabetes mellitus (GDM) or pre-existing diabetes among Aboriginal women in the Northern Territory (NT), Australia. Methods We undertook a longitudinal study of linked healthcare datasets. All Aboriginal women who gave birth between 2000 and 2016 were eligible for inclusion. Diabetes status in the index pregnancy was as recorded in the NT Perinatal Data Collection. Outcomes included any stage of CKD and ESKD as defined by ICD-10 coding in the NT Hospital Inpatient Activity dataset between 2000 and 2018. Risk was compared using Cox proportional hazards regression. Results Among 10,508 Aboriginal women, the mean age was 23.1 (SD 6.1) years; 731 (7.0%) had GDM and 239 (2.3%) had pre-existing diabetes in pregnancy. Median follow-up was 12.1 years. Compared with women with no diabetes during pregnancy, women with GDM had increased risk of CKD (9.2% vs 2.2%, adjusted HR 5.2 [95% CI 3.9, 7.1]) and ESKD (2.4% vs 0.4%, adjusted HR 10.8 [95% CI 5.6, 20.8]). Among women with pre-existing diabetes in pregnancy, 29.1% developed CKD (adjusted HR 10.9 [95% CI 7.7, 15.4]) and 9.9% developed ESKD (adjusted HR 28.0 [95% CI 13.4, 58.6]). Conclusions/interpretation Aboriginal women in the NT with GDM or pre-existing diabetes during pregnancy are at high risk of developing CKD and ESKD. Pregnancy presents an important opportunity to identify kidney disease risk. Strategies to prevent kidney disease and address the social determinants of health are needed. Graphical abstract
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- 2023
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3. Malocclusion in children with speech sound disorders and motor speech involvement: a cross-sectional clinical study in Swedish children
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Å. Mogren, C. Havner, A. Westerlund, L. Sjögreen, M. Barr Agholme, and A. Mcallister
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Pediatrics, Perinatology and Child Health ,Dentistry (miscellaneous) - Abstract
Objectives The objectives of this study were to investigate the occurrence, types and severity of malocclusions in children with speech sound disorder (SSD) persisting after 6 years of age, and to compare these findings to a control group of children with typical speech development (TSD). Methods In total, 105 children were included: 61 with SSD and motor speech involvement (mean age 8:5 ± 2:8 years; range 6:0–16:7 years, 14 girls and 47 boys) and 44 children with TSD (mean age 8:8 ± 1:6; range 6:0–12:2 years, 19 girls and 25 boys). Extra-oral and intra-oral examinations were performed by an orthodontist. The severity of malocclusion was scored using the IOTN-DHC Index. Results There were differences between the SSD and TSD groups with regard to the prevalence, type, and severity of malocclusions; 61% of the children in the SSD group had a malocclusion, as compared to 29% in the TSD group. In addition, the malocclusions in the SSD group were rated as more severe. Functional posterior crossbite and habitual lateral and/or anterior shift appeared more frequently in the SSD group. Class III malocclusion, anterior open bite and scissors bite were found only in the SSD group. Conclusion Children with SSD and motor speech involvement are more likely to have a higher prevalence of and more severe malocclusions than children with TSD.
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- 2022
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4. Crystallization kinetics and thermodynamics of an Ag–In–Sb–Te phase change material using complementary in situ microscopic techniques
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Isak McGieson, Victoriea L. Bird, Christopher M. Barr, Khalid Hattar, Bryan W. Reed, Joseph T. McKeown, Feng Yi, David A. LaVan, and M. K. Santala
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,Condensed Matter Physics - Published
- 2022
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5. Reduction in Substance-Related Composite Harm Scores Through Street Soccer
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Alan T Bates, Lurdes Tse-Agha, Arun Agha, John-Jose Nunez, Heidi N Boyda, Andrea A Jones, Alasdair M Barr, William G Honer, and Fidel Vila-Rodriguez
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General Engineering - Published
- 2023
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6. The mechanical response of micron-sized molecular crystals
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Christopher M. Barr, Daniel Charles Bufford, Marcia A. Cooper, and Jeremy B. Lechman
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Work (thermodynamics) ,Materials science ,Yield (engineering) ,Mechanical Engineering ,Condensed Matter Physics ,Microstructure ,Crystal ,Creep ,Mechanics of Materials ,Fracture (geology) ,Particle ,General Materials Science ,Composite material ,Displacement (fluid) - Abstract
Microstructures and corresponding properties of compacted powders ultimately depend on the mechanical response of individual particles. In principle, computational simulations can predict the results of powder compaction processes, but the selection of appropriate models for both particle–particle interactions and particle deformations across all relevant length scales remain nontrivial tasks, especially in material systems lacking detailed mechanical property information. The work presented here addresses these issues by conducting uniaxial compressions in situ inside of a scanning electron microscope to characterize the mechanical response of individual micron-sized particles of a molecular crystal, hexanitrohexaazaisowurtzitane (CL-20). This experimental approach enabled the collection of quantitative force and displacement data alongside simultaneous imaging to capture morphology changes. The results reveal information about elastic deformation, yield, plastic deformation, creep, and fracture phenomena. Accordingly, this work demonstrates a generalizable approach for assessing the mechanical response of individual micron-sized molecular crystal particles and utilizing those responses in particle-level models. Graphic abstract
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- 2021
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7. Proteomic identification of select protein variants of the SNARE interactome associated with cognitive reserve in a large community sample
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Philip L. De Jager, Sue Leurgans, Alasdair M. Barr, William G. Honer, Julie A. Schneider, Kaitlin B. Casaletto, Vilte E. Barakauskas, Andrea A. Jones, Vladislav A. Petyuk, David A. Bennett, and Alfredo Ramos-Miguel
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0301 basic medicine ,STX1A ,STX1B ,SNAP25 ,Cognition ,Neuropathology ,Biology ,medicine.disease ,Pathology and Forensic Medicine ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,030104 developmental biology ,0302 clinical medicine ,medicine ,Synaptopathy ,Neurology (clinical) ,Prefrontal cortex ,Neuroscience ,030217 neurology & neurosurgery ,Cognitive reserve - Abstract
Age-related neuropathologies progressively impair cognitive abilities by damaging synaptic function. We aimed to identify key components within the presynaptic SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) machinery associated with cognitive performance and estimate their potential contribution to brain reserve in old age. We used targeted SRM proteomics to quantify amounts of 60 peptides, encoded in 30 different genes, in postmortem specimens of the prefrontal cortex from 1209 participants of two aging studies, with available antemortem cognitive evaluations and postmortem neuropathologic assessments. We found that select (but not all) proteoforms are strongly associated with cognitive function and the burden of Alzheimer's disease (AD) pathology. Specifically, greater abundance of STX1A (but not other syntaxins), SYT12, full-length SNAP25, and the GABAergic STXBP1 variant were robustly associated with better cognitive performance. By contrast, greater abundance of other presynaptic proteins (e.g., STXBP5 or tomosyn, STX7, or SYN2) showed a negative influence on cognition. Regression models adjusting for demographic and pathologic variables showed that altered levels of these protein species explained 7.7% additional between-subject variance in cognition (more than any individual age-related neuropathology in the model), suggesting that these molecules constitute key elements of brain reserve. Network analyses indicated that those peptides associated with brain reserve, and closest to the SNARE fusogenic activity, showed greater centrality measures and were better connected in the network. Validation assays confirmed the selective loss of the STX1A (but not STX1B) isoform in cognitively impaired cases. In rodent and human brains, STX1A was selectively located at glutamatergic terminals. However, in AD brains, STX1A was redistributed adjacent to neuritic pathology, and markedly expressed in astrocytes. Our study provides strong evidence, indicating that select presynaptic proteins are key in maintaining brain reserve. Compromised ability to sustain expression levels of these proteins may trigger synaptic dysfunction and concomitant cognitive impairment.
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- 2021
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8. Inelastic peridynamic model for molecular crystal particles
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Marcia A. Cooper, Christopher M. Barr, Jeremy B. Lechman, Stewart A. Silling, and Daniel Charles Bufford
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Fluid Flow and Transfer Processes ,Numerical Analysis ,Materials science ,Deformation (mechanics) ,0211 other engineering and technologies ,Computational Mechanics ,02 engineering and technology ,Mechanics ,Nanoindentation ,Plasticity ,01 natural sciences ,Energetic material ,010101 applied mathematics ,Computational Mathematics ,Contact mechanics ,Creep ,Modeling and Simulation ,Solid mechanics ,Fracture (geology) ,0101 mathematics ,021101 geological & geomatics engineering ,Civil and Structural Engineering - Abstract
The peridynamic theory of solid mechanics is applied to modeling the deformation and fracture of micrometer-sized particles made of organic crystalline material. A new peridynamic material model is proposed to reproduce the elastic–plastic response, creep, and fracture that are observed in experiments. The model is implemented in a three-dimensional, meshless Lagrangian simulation code. In the small deformation, elastic regime, the model agrees well with classical Hertzian contact analysis for a sphere compressed between rigid plates. Under higher load, material and geometrical nonlinearity is predicted, leading to fracture. The material parameters for the energetic material CL-20 are evaluated from nanoindentation test data on the cyclic compression and failure of micrometer-sized grains.
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- 2021
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9. A new hypertonic saline assay for analgesic screening in mice: effects of animal strain, sex, and diurnal phase
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Desmond H. Fung, Alasdair M. Barr, Ernest Puil, Timothy Fung, Stephan K. W. Schwarz, Yahya I. Asiri, and Bernard A. MacLeod
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medicine.medical_specialty ,business.industry ,Analgesic ,General Medicine ,Hypertonic saline ,03 medical and health sciences ,0302 clinical medicine ,Anesthesiology and Pain Medicine ,Nociception ,Endocrinology ,Biting ,030202 anesthesiology ,In vivo ,Internal medicine ,Anesthesia ,medicine ,Morphine ,Circadian rhythm ,business ,Licking ,030217 neurology & neurosurgery ,medicine.drug - Abstract
There exists a pressing need for the identification of novel analgesics. We recently reported on a new preclinical assay for rapid analgesic screening based on intraplantar (i.pl.) injection of 10% hypertonic saline (HS) in female outbred (CD-1) mice. Herein, we characterized the HS assay’s performance in inbred (C57BL/6) mice, sensitivity to sex differences, and effects of diurnal rhythm phase. In randomized, controlled, blinded in vivo animal experiments, we studied nociceptive responses induced by i.pl. HS in C57BL/6 (vs CD-1) mice of both sexes (n = 240) and determined diurnal rhythm phase effects in female animals. We established the HS assay’s sensitivity to morphine by constructing dose-response curves and calculating half-maximal inhibitory doses (ID50s). The injection of i.pl. HS produced nociceptive (licking and biting) responses in all C57BL/6 mice tested. In both C57BL/6 and CD-1 mice, the mean (95% confidence interval [CI]) response magnitudes were greater in females vs males (C57BL/6: 87 sec [64 to 110] vs 45 sec [29 to 61]; difference in means, 42 sec; 95% CI, 17 to 68; P < 0.001; n = 10/group; CD-1: 110 sec [95 to 126] vs 53 sec [32 to 74]; difference in means, 57 sec; 95% CI, 34 to 79; P < 0.001; n = 10/group). The mean (95% CI) nociceptive responses were greater at 24:00 hr than at 12:00 hr in C57BL/6 mice (64 sec [40 to 88] vs 37 sec [24 to 51]; difference in means, 27 sec; 95% CI, 7 to 47; P = 0.007; n = 10/group), but not in CD-1 mice (P = 0.97). Intravenous morphine dose-dependently attenuated nociceptive responses of both C57BL/6 and CD-1 mice (ID50, 0.6 and 2.5 mg·kg−1, respectively; P = 0.41). These findings in inbred and outbred mice solidify the utility of the HS assay as an effective, rapid, robust, and versatile preclinical tool for analgesic screening.
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- 2021
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10. Malocclusion in children with speech sound disorders and motor speech involvement: a cross-sectional clinical study in Swedish children
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Mogren, Å., primary, Havner, C., additional, Westerlund, A., additional, Sjögreen, L., additional, Agholme, M. Barr, additional, and Mcallister, A., additional
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- 2022
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11. Therapeutic ISCOMATRIX™ adjuvant vaccine elicits effective anti-tumor immunity in the TRAMP-C1 mouse model of prostate cancer
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Anabel Silva, Adriana Baz Morelli, Adele M. Barr, Eugene Maraskovsky, Gabrielle T. Belz, and Sandro Prato
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Male ,Cancer Research ,medicine.medical_treatment ,Melanoma, Experimental ,TRAMPC1 ,Apoptosis ,NK cells ,CD8-Positive T-Lymphocytes ,Mice ,Prostate cancer ,Tumor Cells, Cultured ,Tumor Microenvironment ,Immunology and Allergy ,Phospholipids ,Adjuvant ,Tumor antigen ,Drug Combinations ,Cholesterol ,Oncology ,Prostatic acid phosphatase ,Original Article ,Ovalbumin ,Immunology ,Cancer Vaccines ,Interferon-gamma ,Adjuvants, Immunologic ,Antigens, Neoplasm ,medicine ,Animals ,Humans ,Cell Proliferation ,Tumor microenvironment ,business.industry ,Membrane Proteins ,Prostatic Neoplasms ,Cancer ,Immunotherapy ,Saponins ,Therapeutic vaccine ,medicine.disease ,Xenograft Model Antitumor Assays ,CD4+ T cells ,Mice, Inbred C57BL ,Disease Models, Animal ,Poly I-C ,Cancer research ,Cancer vaccine ,business - Abstract
Cancer vaccine development has proven challenging with the exception of some virally induced cancers for which prophylactic vaccines exist. Currently, there is only one FDA approved vaccine for the treatment of prostate cancer and as such prostate cancer continues to present a significant unmet medical need. In this study, we examine the effectiveness of a therapeutic cancer vaccine that combines the ISCOMATRIX™ adjuvant (ISCOMATRIX) with the Toll-like receptor 3 agonist, polyinosinic–polycytidylic acid (Poly I:C), and Flt3L, FMS-like tyrosine kinase 3 ligand. We employed the TRAMP-C1 (transgenic adenocarcinoma of the mouse prostate) model of prostate cancer and the self-protein mPAP (prostatic acid phosphatase) as the tumor antigen. ISCOMATRIX™–mPAP–Poly I:C–Flt3L was delivered in a therapeutic prime-boost regime that was consistently able to achieve complete tumor regression in 60% of animals treated and these tumor-free animals were protected upon rechallenge. Investigations into the underlying immunological mechanisms contributing to the effectiveness of this vaccine identified that both innate and adaptive responses are elicited and required. NK cells, CD4+ T cells and interferon-γ were all found to be critical for tumor control while tumor infiltrating CD8+ T cells became disabled by an immunosuppressive microenvironment. There is potential for broader application of this cancer vaccine, as we have been able to demonstrate effectiveness in two additional cancer models; melanoma (B16-OVA) and a model of B cell lymphoma (Eµ-myc-GFP-OVA). Electronic supplementary material The online version of this article (10.1007/s00262-020-02597-6) contains supplementary material, which is available to authorized users.
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- 2020
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12. Application of In Situ TEM to Investigate Irradiation Creep in Nanocrystalline Zirconium
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Aman Haque, Baoming Wang, Khalid Hattar, Christopher M. Barr, and Daniel Charles Bufford
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Zirconium ,Materials science ,0211 other engineering and technologies ,General Engineering ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Nanocrystalline material ,Ion ,Creep ,chemistry ,Transmission electron microscopy ,Ultimate tensile strength ,Radiation damage ,General Materials Science ,Irradiation ,Composite material ,0210 nano-technology ,021102 mining & metallurgy - Abstract
This work characterizes the irradiation creep response of nanocrystalline zirconium by nanoscale quantitative tensile loading and ion irradiation experiments performed simultaneously in situ inside a transmission electron microscope. Microfabricated devices consisting of a freestanding Zr tensile specimen 100 nm in thickness on an elastic Si test frame were produced, and subsequent ex situ ion irradiations were performed on devices with 1.4 MeV Zr ions to a nominal damage level of 0.26 displacement per atom. Subsequent in situ creep experiments performed with and without 1.4 MeV Zr ion irradiation at different applied tensile loads revealed that creep rates were enhanced by the simultaneous radiation damage. This coupled in situ nanomechanical and irradiation methodology enables rapid quantification of both the irradiation creep compliance and associated microstructural evolution.
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- 2019
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13. A comparison of regional brain volumes and white matter connectivity in subjects with stimulant induced psychosis versus schizophrenia
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Donna J. Lang, Alex Cheng, William J. Panenka, Kristina M. Gicas, Peter D Alexander, Fidel Vila-Rodriguez, Ric M. Procyshyn, Alexandra T. Vertinsky, Allen E. Thornton, Jamie Y X Wong, Tasha Chan, William G. Honer, Andrea A. Jones, Alexander Rauscher, and Alasdair M. Barr
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Adult ,Male ,Psychosis ,medicine.medical_specialty ,Population ,Audiology ,behavioral disciplines and activities ,Psychoses, Substance-Induced ,Temporal lobe ,Cohort Studies ,White matter ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Neuroimaging ,mental disorders ,Fractional anisotropy ,medicine ,Humans ,Longitudinal Studies ,education ,Pharmacology ,Brain Mapping ,education.field_of_study ,business.industry ,Brain ,Middle Aged ,medicine.disease ,White Matter ,030227 psychiatry ,Diffusion Tensor Imaging ,medicine.anatomical_structure ,Schizophrenia ,Central Nervous System Stimulants ,Female ,Schizophrenic Psychology ,business ,Neurocognitive ,030217 neurology & neurosurgery - Abstract
Schizophrenia and stimulant-induced psychosis (SIP) represent two different forms of psychotic disorder, with different etiologies. While many of the symptoms of psychosis are common to both disorders, there have been few direct comparisons between these conditions, especially when controlling for stimulant use in individuals with schizophrenia. We directly compared both psychotic disorders with a comprehensive battery of clinical, neurocognitive and neuroanatomical measures. This included one group with SIP (and concurrent stimulant dependence) and two groups with schizophrenia (either with or without concurrent stimulant dependence). Ninety-six participants were recruited from a marginalized urban population, which included 39 with SIP (and concurrent stimulant dependence), 18 with schizophrenia (without stimulant dependence), and 39 with schizophrenia (with concurrent stimulant dependence). All subjects had extensive clinical and neurocognitive evaluations, complemented with structural MRI including diffusion tensor imaging (DTI) sequences to determine regional brain volumes and white matter connectivity. Both positive and negative symptoms were greater in the SZ-dependent group than the other two. Neurocognitive function was broadly similar. The structural brain imaging revealed lateralized changes to the left parietal/temporal lobe, in which regional volumes were smaller in the SZ-dependent than the SZ-non-dependent group. DTI analysis indicated extensive decreases in fractional anisotropy, with parallel increases in radial diffusivity, in the SIP group compared to the SZ-dependent group. These findings reveal both similarities and differences between SIP and schizophrenia. Furthermore, schizophrenia with concurrent stimulant dependence may be associated with a different clinical and neuroanatomical profile as compared to schizophrenia alone.
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- 2019
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14. Interplay Between Grain Boundaries and Radiation Damage
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Osman El-Atwani, Khalid Hattar, Christopher M. Barr, and Djamel Kaoumi
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geography ,Materials science ,geography.geographical_feature_category ,0211 other engineering and technologies ,General Engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Crystallographic defect ,Engineering physics ,Sink (geography) ,Radiation damage ,General Materials Science ,Grain boundary ,0210 nano-technology ,021102 mining & metallurgy - Abstract
The need for enhanced radiation-tolerant materials for advanced nuclear energy designs has resulted in a growing number of investigations that have explored the effect of grain boundaries under irradiation. The key motivation for examining the role of grain boundaries in radiation environments is the ability to tailor grain boundary networks through either the introduction of specific grain boundaries or an increase in the grain boundary density. While traditionally thought to be efficient sinks for radiation-induced point defects, many recent experimental studies in model and pure systems have shown significant heterogeneity in grain boundary-defect interactions and associated sink efficiency as a function of grain boundary character. Furthermore, grain boundaries can migrate under irradiation, which creates an additional level of complexity. This article will provide a prospective on the experimental observations associated with defect evolution near grain boundaries including variation in sink efficiency and grain boundary mobility in radiation environments.
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- 2019
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15. Hardening in Au-Ag nanoboxes from stacking fault-dislocation interactions
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Khalid Hattar, Mehrdad T. Kiani, Christopher M. Barr, Zachary H. Aitken, Shuai Chen, David Doan, X. Wendy Gu, Yong-Wei Zhang, and Radhika P. Patil
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Materials science ,Scanning electron microscope ,Science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Molecular dynamics ,Composite material ,lcsh:Science ,Porosity ,Multidisciplinary ,Structural properties ,Metals and alloys ,General Chemistry ,Strain hardening exponent ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Transmission electron microscopy ,Hardening (metallurgy) ,Nanoparticles ,lcsh:Q ,Dislocation ,0210 nano-technology ,Stacking fault - Abstract
Porous, nano-architected metals with dimensions down to ~10 nm are predicted to have extraordinarily high strength and stiffness per weight, but have been challenging to fabricate and test experimentally. Here, we use colloidal synthesis to make ~140 nm length and ~15 nm wall thickness hollow Au-Ag nanoboxes with smooth and rough surfaces. In situ scanning electron microscope and transmission electron microscope testing of the smooth and rough nanoboxes show them to yield at 130 ± 45 MPa and 96 ± 31 MPa respectively, with significant strain hardening. A higher strain hardening rate is seen in rough nanoboxes than smooth nanoboxes. Finite element modeling is used to show that the structure of the nanoboxes is not responsible for the hardening behavior suggesting that material mechanisms are the source of observed hardening. Molecular dynamics simulations indicate that hardening is a result of interactions between dislocations and the associated increase in dislocation density., Fabricating and mechanically testing nanoarchitected materials remains a challenge. Here, the authors use colloidal synthesis to fabricate Au-Ag hollow nanoboxes and investigate the effect of either a rough or a smooth nanobox surface on the mechanical properties.
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- 2020
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16. In Situ High-Cycle Fatigue Reveals Importance of Grain Boundary Structure in Nanocrystalline Cu-Zr
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Guild Copeland, Brad L. Boyce, Christopher M. Barr, Timothy J. Rupert, Khalid Hattar, Jennifer D. Schuler, and Nathan M. Heckman
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Toughness ,Materials science ,0211 other engineering and technologies ,General Engineering ,Nucleation ,food and beverages ,Fracture mechanics ,02 engineering and technology ,Intergranular corrosion ,021001 nanoscience & nanotechnology ,Nanocrystalline material ,Amorphous solid ,mental disorders ,General Materials Science ,Grain boundary ,Thin film ,Composite material ,0210 nano-technology ,021102 mining & metallurgy - Abstract
Nanocrystalline metals typically have high fatigue strengths but low resistance to crack propagation. Amorphous intergranular films are disordered grain boundary complexions that have been shown to delay crack nucleation and slow crack propagation during monotonic loading by diffusing grain boundary strain concentrations, which suggests they may also be beneficial for fatigue properties. To probe this hypothesis, in situ transmission electron microscopy fatigue cycling is performed on Cu-1 at.% Zr thin films thermally treated to have either only ordered grain boundaries or amorphous intergranular films. The sample with only ordered grain boundaries experienced grain coarsening at crack initiation followed by unsteady crack propagation and extensive nanocracking, whereas the sample containing amorphous intergranular films had no grain coarsening at crack initiation followed by steady crack propagation and distributed plastic activity. Microstructural design for control of these behaviors through simple thermal treatments can allow for the improvement of nanocrystalline metal fatigue toughness.
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- 2019
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17. Antipsychotic-Associated Symptoms of Tourette Syndrome: A Systematic Review
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Bruce Carleton, Ric M. Procyshyn, Randall F. White, Yunsun Chung, Jessica W. Y. Yuen, Mahyar Etminan, Alasdair M. Barr, David D. Kim, and William G. Honer
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congenital, hereditary, and neonatal diseases and abnormalities ,Pediatrics ,medicine.medical_specialty ,Tics ,medicine.medical_treatment ,Coprolalia ,Tardive dyskinesia ,Tourette syndrome ,03 medical and health sciences ,0302 clinical medicine ,mental disorders ,medicine ,Humans ,Pharmacology (medical) ,Family history ,Antipsychotic ,business.industry ,medicine.disease ,030227 psychiatry ,Discontinuation ,Psychiatry and Mental health ,Schizophrenia ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Antipsychotic Agents ,Tourette Syndrome - Abstract
Although antipsychotics are used to treat Tourette syndrome, there have been reports of paradoxical induction of tics by first- and second-generation antipsychotics. The objective of this systematic review was to better characterize tics as the potential adverse effect of antipsychotics. A literature search was performed, with no language restriction, using the MEDLINE, EMBASE, and PsycINFO databases for all publications up to January 2018. To be included, studies utilizing any study design had to meet the following criteria: (1) a temporal association of tics with antipsychotic use where tics emerged during treatment or after discontinuation and (2) no diagnosis of Tourette syndrome before tic emergence. More stringent criteria were used for individuals under 18 years of age that included (1) no personal or family history of primary tic disorder and either (2) tics occurring during antipsychotic treatment improved significantly upon discontinuation or dose reduction or (3) tics emerged after discontinuation of at least 3 months of antipsychotic treatment. Data were extracted according to: age, sex, diagnosis, personal history of motor symptoms or family history of tics, antipsychotic type and dose, treatment duration, types of symptoms emerged, treatment strategies, and follow-up. A Fisher’s exact test was used to compare the occurrence of symptoms between first- and second-generation antipsychotic users. The search identified 1290 articles, of which 92 full-text articles were assessed leading to the inclusion of 50 articles. Most of the included articles were case reports or series, involving a total of 60 cases. Thirty cases were associated with treatment with first-generation antipsychotics, 27 with second-generation antipsychotics, and three with a combination of first- and second-generation antipsychotics. Antipsychotics were being used to treat schizophrenia in 60% of the cases and other indications included developmental, behavioral, and mood or anxiety disorders. Tics occurred during treatment (n = 44) or following treatment discontinuation (n = 16). The occurrence of vocal tics with or without motor tics was significantly higher in the first- vs. second-generation antipsychotic users (p
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- 2018
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18. Grain boundary phase transformations in PtAu and relevance to thermal stabilization of bulk nanocrystalline metals
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Stephen M. Foiles, Khalid Hattar, Patrick M. Price, Christopher M. Barr, and Christopher J. O’Brien
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010302 applied physics ,Work (thermodynamics) ,Materials science ,Mechanical Engineering ,Monte Carlo method ,Boundary (topology) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Nanocrystalline material ,Condensed Matter::Materials Science ,Crystallography ,Mechanics of Materials ,Chemical physics ,Phase (matter) ,0103 physical sciences ,Solid mechanics ,General Materials Science ,Grain boundary ,0210 nano-technology - Abstract
There has recently been a great deal of interest in employing immiscible solutes to stabilize nanocrystalline microstructures. Existing modeling efforts largely rely on mesoscale Monte Carlo approaches that employ a simplified model of the microstructure and result in highly homogeneous segregation to grain boundaries. However, there is ample evidence from experimental and modeling studies that demonstrates segregation to grain boundaries is highly non-uniform and sensitive to boundary character. This work employs a realistic nanocrystalline microstructure with experimentally relevant global solute concentrations to illustrate inhomogeneous boundary segregation. Experiments quantifying segregation in thin films are reported that corroborate the prediction that grain boundary segregation is highly inhomogeneous. In addition to grain boundary structure modifying the degree of segregation, the existence of a phase transformation between low and high solute content grain boundaries is predicted. In order to conduct this study, new embedded atom method interatomic potentials are developed for Pt, Au, and the PtAu binary alloy.
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- 2017
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19. Heart-rate response to alpha2-adrenergic receptor antagonism by antipsychotics
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Ric M. Procyshyn, Melissa L. Woodward, Randall F. White, Donna J. Lang, David D. Kim, Alasdair M. Barr, William G. Honer, and Darren E. R. Warburton
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medicine.medical_specialty ,Neurology ,Endocrine and Autonomic Systems ,business.industry ,030204 cardiovascular system & hematology ,medicine.disease ,behavioral disciplines and activities ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Schizophrenia ,Internal medicine ,Diabetes mellitus ,mental disorders ,Heart rate ,medicine ,Alpha-2 adrenergic receptor ,Neurology (clinical) ,Receptor ,Antagonism ,business ,Dopamine hypothesis of schizophrenia ,030217 neurology & neurosurgery - Abstract
Purpose To explore the relationship between antipsychotic-associated antagonism of alpha2-adrenergic receptors and resting heart rate in individuals with schizophrenia.
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- 2017
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20. Extended follow-up and impact of high-risk prognostic factors from the phase 3 RESONATE study in patients with previously treated CLL/SLL
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Nishitha Reddy, L. Gau, Betty Y. Chang, Richard R. Furman, D.F. James, Susan O'Brien, Constantine S. Tam, John C. Byrd, Ulrich Jaeger, Peter Hillmen, Jennifer R. Brown, Sven DeVos, Paul M. Barr, Marco Montillo, Talha Munir, Federico Caligaris-Cappio, Emily Hsu, Stephen P. Mulligan, Florence Cymbalista, John M. Pagel, Julio Delgado, D. Chung, Carol Moreno, Thomas J. Kipps, Patrick Thornton, Jennifer H. Lin, Jan A. Burger, Jaqueline C. Barrientos, S. E. Coutre, and George Cole
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Male ,Oncology ,Cancer Research ,Lymphoma ,Chronic lymphocytic leukemia ,chemistry.chemical_compound ,0302 clinical medicine ,Piperidines ,Monoclonal ,80 and over ,Medicine ,Chronic ,Humanized ,Cancer ,Aged, 80 and over ,Leukemia ,Hematology ,Antibodies, Monoclonal ,Middle Aged ,Prognosis ,Lymphocytic ,Local ,6.1 Pharmaceuticals ,030220 oncology & carcinogenesis ,Ibrutinib ,Female ,Original Article ,Rituximab ,medicine.drug ,Adult ,medicine.medical_specialty ,Clinical Sciences ,Oncology and Carcinogenesis ,Immunology ,Antineoplastic Agents ,Antibodies, Monoclonal, Humanized ,Ofatumumab ,Antibodies ,Disease-Free Survival ,03 medical and health sciences ,Rare Diseases ,Clinical Research ,Internal medicine ,Genetics ,Humans ,Aged ,business.industry ,Adenine ,B-Cell ,Evaluation of treatments and therapeutic interventions ,medicine.disease ,Leukemia, Lymphocytic, Chronic, B-Cell ,Surgery ,Clinical trial ,Neoplasm Recurrence ,Pyrimidines ,chemistry ,Mutation ,Pyrazoles ,Neoplasm Recurrence, Local ,Tumor Suppressor Protein p53 ,business ,Follow-Up Studies ,030215 immunology - Abstract
In the phase 3 RESONATE study, ibrutinib demonstrated superior progression-free survival (PFS), overall survival (OS) and overall response rate (ORR) compared with ofatumumab in relapsed/refractory CLL patients with high-risk prognostic factors. We report updated results from RESONATE in these traditionally chemotherapy resistant high-risk genomic subgroups at a median follow-up of 19 months. Mutations were detected by Foundation One Heme Panel. Baseline mutations in the ibrutinib arm included TP53 (51%), SF3B1 (31%), NOTCH1 (28%), ATM (19%) and BIRC3 (14%). Median PFS was not reached, with 74% of patients randomized to ibrutinib alive and progression-free at 24 months. The improved efficacy of ibrutinib vs ofatumumab continues in all prognostic subgroups including del17p and del11q. No significant difference within the ibrutinib arm was observed for PFS across most genomic subtypes, although a subset carrying both TP53 mutation and del17p had reduced PFS compared with patients with neither abnormality. Reduced PFS or OS was not evident in patients with only del17p. PFS was significantly better for ibrutinib-treated patients in second-line vs later lines of therapy. The robust clinical activity of ibrutinib continues to show ongoing efficacy and acceptable safety consistent with prior reports, independent of various known high-risk mutations.
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- 2017
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21. Presynaptic proteins complexin-I and complexin-II differentially influence cognitive function in early and late stages of Alzheimer’s disease
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Ken Sawada, David A. Bennett, Alfredo Ramos-Miguel, Julie A. Schneider, Andrea A. Jones, William G. Honer, Allen E. Thornton, Alasdair M. Barr, and Sue Leurgans
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Male ,0301 basic medicine ,Aging ,Pathology ,medicine.medical_specialty ,Vesicular Inhibitory Amino Acid Transport Proteins ,Presynaptic Terminals ,Enzyme-Linked Immunosorbent Assay ,Nerve Tissue Proteins ,Neuropathology ,Biology ,Article ,Pathology and Forensic Medicine ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Complexin ,Alzheimer Disease ,Residence Characteristics ,medicine ,Animals ,Humans ,Dementia ,Rats, Long-Evans ,Cognitive decline ,Maze Learning ,Aged ,Cognitive reserve ,Aged, 80 and over ,Brain ,Cognition ,medicine.disease ,Rats ,Adaptor Proteins, Vesicular Transport ,030104 developmental biology ,Vesicular Glutamate Transport Protein 1 ,Disease Progression ,Female ,Autopsy ,Neurology (clinical) ,Alzheimer's disease ,Cognition Disorders ,Neuroscience ,030217 neurology & neurosurgery ,Braak staging - Abstract
Progressive accumulation of Alzheimer’s disease-related pathology is associated with cognitive dysfunction. Differences in cognitive reserve may contribute to individual differences in cognitive function in the presence of comparable neuropathology. The protective effects of cognitive reserve could contribute differentially in early versus late stages of the disease. We investigated presynaptic proteins as measures of brain reserve (a subset of total cognitive reserve), and used Braak staging to estimate the progression of Alzheimer’s disease. Antemortem evaluations of cognitive function, postmortem assessments of pathologic indices, and presynaptic protein analyses, including the complexins I and II as respective measures of inhibitory and excitatory terminal function, were assayed in multiple key brain regions in 418 deceased participants from a community study. After covarying for demographic variables, pathologic indices, and overall synapse density, lower brain complexin-I and -II levels contributed to cognitive dysfunction (P < 0.01). Each complexin appeared to be dysregulated at a different Braak stage. Inhibitory complexin-I explained 14.4% of the variance in global cognition in Braak 0-II, while excitatory complexin-II explained 7.3% of the variance in Braak V-VI. Unlike other presynaptic proteins, complexins did not colocalize with pathologic tau within neuritic plaques, suggesting that these functional components of the synaptic machinery are cleared early from dystrophic neurites. Moreover, complexin levels showed distinct patterns of change related to memory challenges in a rat model, supporting the functional specificity of these proteins. The present results suggest that disruption of inhibitory synaptic terminals may trigger early cognitive impairment, while excitatory terminal disruption may contribute relatively more to later cognitive impairment.
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- 2016
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22. Confirmatory factor analysis of the neck disability index, comparing patients with whiplash associated disorders to a control group with non-specific neck pain
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Stephanie Winkeljohn Black, Markus Melloh, Charles Philip Gabel, Antonio Cuesta-Vargas, Sebastian M. Barr, and Jason W. Osborne
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Adult ,Male ,medicine.medical_specialty ,Psychometrics ,Cross-sectional study ,Population ,Disability Evaluation ,03 medical and health sciences ,0302 clinical medicine ,Whiplash ,medicine ,Humans ,Orthopedics and Sports Medicine ,Patient Reported Outcome Measures ,education ,Whiplash Injuries ,Pain Measurement ,030222 orthopedics ,Neck pain ,education.field_of_study ,Neck Pain ,business.industry ,Middle Aged ,medicine.disease ,Control Groups ,Confirmatory factor analysis ,Cross-Sectional Studies ,Physical therapy ,Female ,Surgery ,Patient-reported outcome ,medicine.symptom ,Factor Analysis, Statistical ,business ,030217 neurology & neurosurgery ,Neck Disability Index - Abstract
Purpose The neck disability index (NDI) as a 10-item patient reported outcome (PRO) measure is the most commonly used whiplash associated disorders (WAD) assessment tool. However, statistical rigor and factor structure are not definitive. To date, confirmatory factor analysis (CFA) has not examined whether the factor structure generalizes across different groups (e.g., WAD versus non-WAD). This study aimed to determine the psychometric properties of the NDI in these population groups. Methods This study used CFA to analyze NDI baseline-data for WAD (n = 804; 69 % females) and non-WAD (n = 963; 67 % females), each for the full sample and separate genders. Invariance analyses examined the NDI structure across the four groups. Results Across both populations and gender subgroups the one-factor solutions consistently showed better model fit over two-factor solutions. The NDI was best characterized as one-dimensional and invariant across multiple sub-groups. Conclusion The NDI remains a valid PRO in WAD populations that provides acceptable measurement of neck status that is appropriate for basic functional assessment across genders. However, it is recommended that both clinicians and researchers initiate the transition toward more rigorous and less ambiguous PRO measurement tools for WAD patients and research. This future graduated movement toward other PROs should consider both regional PROs and computerized decision support systems, initially measured concurrently with the NDI to establish ways to convert existing scored data prior to their singular use.
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- 2016
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23. Ciliary Extracellular Vesicles: Txt Msg Organelles
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Juan Wang and Maureen M. Barr
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0301 basic medicine ,biology ,Microvesicle ,Cilium ,Cell Biology ,General Medicine ,Flagellum ,biology.organism_classification ,Bioinformatics ,Ciliopathies ,Exosome ,Article ,Microvesicles ,Cell biology ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,030104 developmental biology ,0302 clinical medicine ,030217 neurology & neurosurgery ,Biogenesis ,Caenorhabditis elegans - Abstract
Cilia are sensory organelles that protrude from cell surfaces to monitor the surrounding environment. In addition to its role as sensory receiver, the cilium also releases extracellular vesicles (EVs). The release of sub-micron sized EVs is a conserved form of intercellular communication used by all three kingdoms of life. These extracellular organelles play important roles in both short and long range signaling between donor and target cells and may coordinate systemic responses within an organism in normal and diseased states. EV shedding from ciliated cells and EV-cilia interactions are evolutionarily conserved phenomena, yet remarkably little is known about the relationship between the cilia and EVs and the fundamental biology of EVs. Studies in the model organisms Chlamydomonas and C. elegans have begun to shed light on ciliary EVs. Chlamydomonas EVs are shed from tips of flagella and are bioactive. C. elegans EVs are shed and released by ciliated sensory neurons in an intraflagellar transport (IFT)-dependent manner. C. elegans EVs play a role in modulating animal-to-animal communication, and this EV bioactivity is dependent on EV cargo content. Some ciliary pathologies, or ciliopathies, are associated with abnormal EV shedding or with abnormal cilia-EV interactions, suggest the cilium may be an important organelle as an EV donor or as an EV target. Until the past few decades, both cilia and EVs were ignored as vestigial or cellular junk. As research interest in these two organelles continues to gain momentum, we envision a new field of cell biology emerging. Here, we propose that the cilium is a dedicated organelle for EV biogenesis and EV reception. We will also discuss possible mechanisms by which EVs exert bioactivity and explain how what is learned in model organisms regarding EV biogenesis and function may provide insight to human ciliopathies.
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- 2016
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24. Tracking the evolution of intergranular corrosion through twin-related domains in grain boundary networks
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Christopher M. Barr, Sebastian Thomas, James L. Hart, Wayne Harlow, Elaf A. Anber, and Mitra L. Taheri
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0301 basic medicine ,Materials science ,Misorientation ,Materials Science (miscellaneous) ,Metallurgy ,Intergranular corrosion ,Microstructure ,Tracking (particle physics) ,01 natural sciences ,Corrosion ,03 medical and health sciences ,030104 developmental biology ,Chemistry (miscellaneous) ,0103 physical sciences ,lcsh:TA401-492 ,Materials Chemistry ,Ceramics and Composites ,Cluster (physics) ,Thermomechanical processing ,lcsh:Materials of engineering and construction. Mechanics of materials ,Grain boundary ,010306 general physics - Abstract
Tailoring the grain boundary network is desired to improve grain boundary-dependent phenomena such as intergranular corrosion. An important grain boundary network descriptor in heavily twinned microstructures is the twin-related domain, a cluster of twin-related grains. We indicate the advantages of using twin-related domains and subsequent statistics to provide new insight into how a grain boundary networks respond to intergranular corrosion in a heavily twinned grain boundary engineered 316L stainless steel. The results highlight that intergranular corrosion is typically arrested inside twin-related domains at coherent twins or low-angle grain boundaries. Isolated scenarios exist, however, where intergranular corrosion propagation persists in the grain boundary network through higher-order twin-related boundaries. Clustered twin grain boundaries in stainless steel can stop intergranular corrosion, but only if they are coherent. A team led by Mitra Taheri at Drexel University in the USA analyzed microstructural regions in a 316 stainless steel where all grain boundaries were twinned and found that, when the twins in these clusters were coherent or had a low misorientation angle, they arrested interganular corrosion. They emphasized this effect by engineering more coherent and low-angle grain boundaries with thermomechanical processing, leading to larger twin-related domains. In contrast, twinned clusters with high-angle grain boundaries consistently failed at resisting corrosion, a similar manner to the rest of steel. Twin-related domains may therefore be a good predictor of intergranular corrosion and may help us mitigate metal damage.
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- 2018
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25. Targeting B cell receptor signaling with ibrutinib in diffuse large B cell lymphoma
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Thomas M. Habermann, Chih Jian Lih, Ranjana H. Advani, Davina Moussa, Andre Goy, Paul M. Barr, Rebecca Elstrom, Nathan Fowler, Fong Clow, Betty Y. Chang, Maria Fardis, Darrin M. Beaupre, Brian Munneke, John F. Gerecitano, Ryan M. Young, Wyndham H. Wilson, Louis M. Staudt, Roland Schmitz, Stefania Pittaluga, Vaishalee P. Kenkre, Yandan Yang, P. Mickey Williams, George E. Wright, Andrei R. Shustov, Julie M. Vose, Jacqueline C. Barrientos, Jesse McGreivy, Sven de Vos, Arthur L. Shaffer, and Kristie A. Blum
- Subjects
Adult ,Male ,Molecular Sequence Data ,B-cell receptor ,Receptors, Antigen, B-Cell ,Biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,Piperidines ,hemic and lymphatic diseases ,medicine ,Humans ,Protein Kinase Inhibitors ,Aged ,Base Sequence ,Adenine ,breakpoint cluster region ,Germinal center ,General Medicine ,Middle Aged ,CD79B ,medicine.disease ,Lymphoma ,Pyrimidines ,chemistry ,Ibrutinib ,Mutation ,Myeloid Differentiation Factor 88 ,Immunology ,Cancer research ,Pyrazoles ,Female ,Lymphoma, Large B-Cell, Diffuse ,Diffuse large B-cell lymphoma ,CD79 Antigens ,Signal Transduction - Abstract
The two major subtypes of diffuse large B cell lymphoma (DLBCL)—activated B cell–like (ABC) and germinal center B cell–like (GCB)—arise by distinct mechanisms, with ABC selectively acquiring mutations that target the B cell receptor (BCR), fostering chronic active BCR signaling(1). The ABC subtype has a ∼40% cure rate with currently available therapies, which is worse than the rate for GCB DLBCL, and highlights the need for ABC subtype-specific treatment strategies(2). We hypothesized that ABC, but not GCB, DLBCL tumors would respond to ibrutinib, an inhibitor of BCR signaling. In a phase 1/2 clinical trial that involved 80 subjects with relapsed or refractory DLBCL, ibrutinib produced complete or partial responses in 37% (14/38) of those with ABC DLBCL, but in only 5% (1/20) of subjects with GCB DLBCL (P = 0.0106). ABC tumors with BCR mutations responded to ibrutinib frequently (5/9; 55.5%), especially those with concomitant myeloid differentiation primary response 88 (MYD88) mutations (4/5; 80%), a result that is consistent with in vitro cooperation between the BCR and MYD88 pathways. However, the highest number of responses occurred in ABC tumors that lacked BCR mutations (9/29; 31%), suggesting that oncogenic BCR signaling in ABC does not require BCR mutations and might be initiated by non-genetic mechanisms. These results support the selective development of ibrutinib for the treatment of ABC DLBCL.
- Published
- 2015
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26. Grain boundary character dependence of radiation-induced segregation in a model Ni–Cr alloy
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Mitra L. Taheri, Dane Morgan, Khalid Hattar, Leland Barnard, Izabela Szlurfarska, James E. Nathaniel, Kinga A. Unocic, and Christopher M. Barr
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Void (astronomy) ,Materials science ,Structural material ,Condensed matter physics ,Mechanical Engineering ,Alloy ,engineering.material ,Condensed Matter Physics ,Mechanics of Materials ,engineering ,Grain boundary diffusion coefficient ,General Materials Science ,Grain boundary ,Boundary value problem ,Irradiation ,Grain boundary strengthening - Abstract
Ni-based fcc alloys are frequently used as critical structural materials in nuclear energy applications. Despite extensive studies, fundamental questions remain regarding point defect migration and solute segregation as a function of grain boundary character after irradiation. In this study, a coupled experimental and modeling approach is used to understand the response of grain boundary character in a model Ni–5Cr alloy after high temperature heavy-ion irradiation. Radiation-induced segregation and void denuded zones were experimentally examined as a function of grain boundary character, while a kinetic rate theory model with grain boundary character boundary conditions was used to theoretically model Cr depletion in the alloy system. The results highlight major variations in the radiation response between the coherent and incoherent twin grain boundaries, but show limited disparity in defect sink strength between random low- and high-angle grain boundary regimes.
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- 2015
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27. Treatment of clozapine-associated weight gain: a systematic review
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Diane H. Fredrikson, Alasdair M. Barr, Ric M. Procyshyn, and Zachary Whitney
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Psychosis ,medicine.medical_specialty ,medicine.medical_treatment ,Psychological intervention ,Weight Gain ,Bioinformatics ,Extrapyramidal symptoms ,medicine ,Humans ,Pharmacology (medical) ,Antipsychotic drug ,Psychiatry ,Antipsychotic ,Clozapine ,Randomized Controlled Trials as Topic ,Pharmacology ,business.industry ,General Medicine ,medicine.disease ,Schizophrenia ,medicine.symptom ,business ,Weight gain ,Antipsychotic Agents ,medicine.drug - Abstract
Clozapine is an antipsychotic drug with superior efficacy in treatment-resistant schizophrenia. Clozapine is associated with a low likelihood of extrapyramidal symptoms and other neurological side-effects but a high propensity to induce weight gain and general metabolic dysregulation. Various pharmacological and behavioral treatment approaches for reducing clozapine-associated weight gain exist in the literature; however, there are currently no clear clinical guidelines as to which method is preferred. The aim of the current review is to systematically summarize studies that have studied both pharmacological and non-pharmacological interventions to attenuate or reverse clozapine-associated weight gain.A systematic review of EMBASE and MEDLINE databases of all articles published prior to January 2014 was conducted. Seventeen studies were identified as meeting inclusion criteria and included in the review.Aripiprazole, fluvoxamine, metformin, and topiramate appear to be beneficial; however, available data are limited to between one and three randomized controlled trials per intervention. Orlistat shows beneficial effects, but in males only. Behavioral and nutritional interventions also show modest effects on decreasing clozapine-associated weight gain, although only a small number of such studies exist.While a number of pharmacological interventions can produce modest weight loss, each may be associated with negative side effects, which should be considered before beginning treatment. Given the pressing need to improve cardiometabolic health in most clozapine-treated patients, substantially more research is needed to develop sound clinical practice guidelines for the treatment of clozapine-associated weight gain.
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- 2015
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28. Postoperative delirium following transcatheter aortic valve implantation: a historical cohort study
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Randell L. Moore, Alasdair M. Barr, John B. Bowering, Stephan K. W. Schwarz, Kyle D. Burns, and Lurdes Tse
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Male ,medicine.medical_specialty ,Cohort Studies ,Transcatheter Aortic Valve Replacement ,Coronary artery disease ,Postoperative Complications ,Risk Factors ,Anesthesiology ,Internal medicine ,medicine ,Humans ,Myocardial infarction ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Delirium ,Retrospective cohort study ,General Medicine ,Odds ratio ,medicine.disease ,Logistic Models ,Anesthesiology and Pain Medicine ,Anesthesia ,Heart failure ,Multivariate Analysis ,Cardiology ,Female ,medicine.symptom ,business ,Cohort study - Abstract
Transcatheter aortic valve implantation (TAVI) techniques show favourable survival outcomes in high-risk patients, but the incidence of postoperative delirium is unknown. We conducted a historical cohort study to compare postoperative delirium in retrograde transfemoral (TF) versus anterograde transapical (TA) TAVI procedures. We also sought to identify independent predictors of delirium following TAVI. We performed a retrospective chart review on all patients who underwent TF (n = 77) or TA (n = 45) TAVI during 2008 and 2009 at St. Paul’s Hospital (Vancouver, BC, Canada), the pioneering centre for these procedures. The primary outcome was a documented physician diagnosis of delirium. Abstracted data included information on demographics, medical history, surgical procedure, anesthesia, and postoperative care. We employed a multivariable logistic regression to identify independent predictors of delirium. Delirium occurred in 12% of TF patients vs 53% of TA patients (P
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- 2014
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29. A motor relay on ciliary tracks
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Robert O'Hagan and Maureen M. Barr
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KIF17 ,Cilium ,Cell Biology ,Anatomy ,Biology ,Topology ,Article ,law.invention ,Cell biology ,Motor protein ,Relay ,law ,Intraflagellar transport ,Microtubule ,Kymography ,Kinesin - Abstract
A powerful combination of two-colour imaging in vivo, Fourier-filtered kymography and simulations provides a high-resolution view of kinesin-2 transport dynamics in cilia. This study reveals heterotrimeric kinesin-II as an 'obstacle-course runner' and homodimeric OSM-3 (KIF17) as a 'long-distance runner', and elucidates the 'baton handoff' between these two kinesin-2 motors on the microtubule track.
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- 2015
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30. Exercise-induced hippocampal neurogenesis: 5-HT3 receptor antagonism by antipsychotics as a potential limiting factor in Schizophrenia
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Alasdair M. Barr, David D. Kim, William G. Honer, and Ric M. Procyshyn
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Limiting factor ,biology ,business.industry ,Neurogenesis ,Hippocampal formation ,medicine.disease ,5-HT3 receptor ,030227 psychiatry ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Psychiatry and Mental health ,0302 clinical medicine ,Schizophrenia ,biology.protein ,Medicine ,Serotonin ,business ,Receptor ,Antagonism ,Molecular Biology ,Neuroscience ,030217 neurology & neurosurgery - Published
- 2018
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31. PDF-1 neuropeptide signaling modulates a neural circuit for mate-searching behavior in C. elegans
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Rajarshi Ghosh, Scott W. Emmons, Chunhui Fang, Maureen M. Barr, and Arantza Barrios
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Male ,Nervous system ,Interneuron ,Disorders of Sex Development ,Neuropeptide ,Sensory system ,Biology ,Ligands ,Article ,Receptors, G-Protein-Coupled ,Animals, Genetically Modified ,Sexual Behavior, Animal ,03 medical and health sciences ,Pigment dispersing factor ,0302 clinical medicine ,medicine ,Animals ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Receptor ,Transcription factor ,030304 developmental biology ,0303 health sciences ,General Neuroscience ,Neuropeptides ,biology.organism_classification ,medicine.anatomical_structure ,Exploratory Behavior ,Female ,Nerve Net ,Neuroscience ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
Appetitive behaviors require complex decision making that involves the integration of environmental stimuli and physiological needs. C. elegans mate searching is a male-specific exploratory behavior regulated by two competing needs: food and reproductive appetite. We found that the pigment dispersing factor receptor (PDFR-1) modulates the circuit that encodes the male reproductive drive that promotes male exploration following mate deprivation. PDFR-1 and its ligand, PDF-1, stimulated mate searching in the male, but not in the hermaphrodite. pdf-1 was required in the gender-shared interneuron AIM, and the receptor acted in internal and external environment-sensing neurons of the shared nervous system (URY, PQR and PHA) to produce mate-searching behavior. Thus, the pdf-1 and pdfr-1 pathway functions in non-sex-specific neurons to produce a male-specific, goal-oriented exploratory behavior. Our results indicate that secretin neuropeptidergic signaling is involved in regulating motivational internal states.
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- 2012
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32. Phenotypic and genetic differentiation among yellow monkeyflower populations from thermal and non-thermal soils in Yellowstone National Park
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Margaret F. Hendrick, Beth Roskilly, Ylva Lekberg, Lila Fishman, Catherine A. Zabinski, and Camille M. Barr
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Genetic Markers ,Mimulus guttatus ,Population ,Mimulus ,Flowers ,Gene flow ,Soil ,Genetic variation ,Pollination ,education ,Ecology, Evolution, Behavior and Systematics ,Local adaptation ,education.field_of_study ,Ecology ,Montana ,Ecotype ,biology ,National park ,Reproduction ,Temperature ,Genetic Variation ,food and beverages ,biology.organism_classification ,Adaptation, Physiological ,Phenotype ,Adaptation - Abstract
In flowering plants, soil heterogeneity can generate divergent natural selection over fine spatial scales, and thus promote local adaptation in the absence of geographic barriers to gene flow. Here, we investigate phenotypic and genetic differentiation in one of the few flowering plants that thrives in both geothermal and non-thermal soils in Yellowstone National Park (YNP). Yellow monkeyflowers (Mimulus guttatus) growing at two geothermal ("thermal") sites in YNP were distinct in growth form and phenology from paired populations growing nearby (500 m distant) in non-thermal soils. In simulated thermal and non-thermal environments, thermal plants remained significantly divergent from non-thermal plants in vegetative, floral, mating system, and phenological traits. Plants from both thermal populations flowered closer to the ground, allocated relatively more to sexual reproduction, were more likely to initiate flowering under short daylengths, and made smaller flowers that could efficiently self-fertilize without pollinators. These shared differences are consistent with local adaptation to life in the ephemeral window for growth and reproduction created by winter and spring snowmelt on hot soils. In contrast, habitat type (thermal vs. non-thermal) explained little of the genetic variation at neutral markers. Instead, we found that one thermal population (Agrostis Headquarters; AHQ-T) was strongly differentiated from all other populations (all F (ST)0.34), which were only weakly differentiated from each other (all F (ST)0.07). Phenotypic differentiation of thermal M. guttatus, but little population genetic evidence of long-term ecotypic divergence, encourages further investigations of the potential for fine-scale adaptation and reproductive isolation across the geothermal gradient in Yellowstone.
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- 2012
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33. Non-Hodgkinʼs Lymphoma in the Elderly
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Nathan A. Berger, Paul M. Barr, Paolo Caimi, and Hillard M. Lazarus
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Bendamustine ,Oncology ,Aging ,medicine.medical_specialty ,Vincristine ,Cyclophosphamide ,Antineoplastic Agents ,CHOP ,Antibodies, Monoclonal, Murine-Derived ,Prednisone ,hemic and lymphatic diseases ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,Pharmacology (medical) ,Renal Insufficiency ,Geriatric Assessment ,Aged ,Aged, 80 and over ,Dose-Response Relationship, Drug ,business.industry ,Incidence ,Lymphoma, Non-Hodgkin ,Antibodies, Monoclonal ,Prognosis ,medicine.disease ,Combined Modality Therapy ,Non-Hodgkin's lymphoma ,Lymphoma ,Surgery ,Rituximab ,Geriatrics and Gerontology ,business ,medicine.drug - Abstract
The expansion of older population segments and the continuous increase in the incidence of non-Hodgkin's lymphoma (NHL) makes this group of neoplasms an important and growing problem. Older NHL patients have increased risk of therapy-related toxicity as a result of age-related physiological changes and frequent co-morbidities. A functional assessment of the elderly patient is necessary to determine the likelihood of tolerating and responding to therapy. The comprehensive geriatric assessment (CGA) is one multidisciplinary tool that has been applied successfully to older cancer patients and aids in identification of subjects who will or will not benefit from anti-neoplastic treatment. Although indolent lymphomas present more frequently at advanced stage, randomized trials do not show better outcomes with early therapy, supporting close observation until specific therapeutic indications arise. Use of the monoclonal antibody rituximab as a single agent or in combination with chemotherapy improves survival and has become the standard of care in first-line treatment. Radioimmunoconjugates, bendamustine, and other monoclonal antibodies as well as novel targeted agents also are active against indolent lymphomas. Diffuse large B-cell lymphoma is an aggressive but potentially curable disease. Several trials performed exclusively in elderly patients have demonstrated improved response rates and survival with the addition of rituximab to CHOP (cyclophosphamide, doxorubicin [adriamycin], vincristine, prednisone) chemotherapy in the front-line setting. Salvage chemotherapy followed by autologous haematopoietic cell transplant (autoHCT) has been shown to have better failure-free and overall survival in randomized trials involving younger patients. Highly selected individuals up to age 70 years may attain long-term survival benefit from autoHCT, although transplant-related mortality is higher than in younger patients.
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- 2010
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34. Omeprazole Induces Gastric Permeability to Digoxin
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James M. Mullin, M. Gabello, Mary Carmen Valenzano, M. Barr, and P. Zurbach
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Male ,Phenytoin ,Drug ,Digoxin ,Physiology ,medicine.drug_class ,media_common.quotation_subject ,Proton-pump inhibitor ,In Vitro Techniques ,Pharmacology ,Permeability ,Tight Junctions ,Rats, Sprague-Dawley ,medicine ,Gastric mucosa ,Animals ,Omeprazole ,media_common ,Ussing chamber ,Chemistry ,digestive, oral, and skin physiology ,Gastroenterology ,Proton Pump Inhibitors ,Hydrogen-Ion Concentration ,Rats ,Electrophysiology ,medicine.anatomical_structure ,Gastric Mucosa ,Paracellular transport ,Chromatography, Thin Layer ,medicine.drug - Abstract
Previous animal and patient-based studies have shown that omeprazole induces a transepithelial paracellular gastric leak. This study reports on the potential for an omeprazole-induced leak of drugs with narrow therapeutic windows. Ussing chamber experiments investigated the effects of omeprazole on rat gastric corpus permeability to the drugs, digoxin and phenytoin. Digoxin (780 MW) permeated the gastric mucosa at an accelerated rate in the presence of omeprazole. This leak could contribute to dangerous elevations of blood digoxin levels in certain situations. Omeprazole was found to have no effect on the flux rate of phenytoin (252 MW). The tight-junctional leak generated by omeprazole thus exhibits specificity to the types of molecules it allows to permeate through the gastric mucosa. This leak may pose a clinical danger by increasing drug uptake into the bloodstream, a phenomenon which would act synergistically with the effect of omeprazole on inhibiting liver cytochrome P450s that remove drugs from the bloodstream, thereby elevating drug blood levels.
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- 2009
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35. Two-hour glucose predicts the development of hypertension over 5 years: the AusDiab study
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Elizabeth L M Barr, Jonathan E. Shaw, Edward J. Boyko, and Paul Zimmet
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Blood Glucose ,Male ,medicine.medical_specialty ,Time Factors ,Waist ,medicine.medical_treatment ,Population ,Prehypertension ,Predictive Value of Tests ,Risk Factors ,Surveys and Questionnaires ,Internal medicine ,Diabetes mellitus ,Blood plasma ,Prevalence ,Internal Medicine ,medicine ,Humans ,Prospective Studies ,Risk factor ,education ,education.field_of_study ,Chi-Square Distribution ,business.industry ,Insulin ,Australia ,nutritional and metabolic diseases ,Glucose Tolerance Test ,Middle Aged ,medicine.disease ,Cross-Sectional Studies ,Logistic Models ,Endocrinology ,Blood pressure ,Hypertension ,Female ,business ,Follow-Up Studies - Abstract
Elevated 2-h plasma glucose concentration (2hPG) from an oral glucose tolerance (OGTT) test more strongly predicts risk of subsequent cardiovascular disease than fasting plasma glucose (FPG), but the association between these glucose measurements and hypertension risk is less clear. We examined the association between 2hPG, FPG and risk of hypertension. We conducted a prospective observational study (The Australian Diabetes, Obesity and Lifestyle Study-AusDiab) among 4413 Australian residents who attended a baseline (1999-2000) and follow-up (2004-2005) examinations. Measurements included blood pressure (mean of two readings), 75 g OGTT, fasting insulin, anthropometrics, dietary and alcohol intake, medical history and physical activity. Hypertension was defined as a systolic blood pressure (SBP)or =140 or a diastolic blood pressure (DBP)or =90 mm Hg or treatment with medication for hypertension. HOMA-S was calculated as a measure of insulin sensitivity using the HOMA2 calculator. Hypertension developed in 14% of the 4306 subjects available for this analysis. Higher 2hPG was significantly related to greater risk of hypertension after adjustment for age, gender, FPG, BMI (baseline and difference), waist circumference (baseline and difference), education, exercise, alcohol intake, baseline SBP and smoking (OR (95% CI) 1.12 (1.01 to 1.23)), but no significant association was seen between FPG and hypertension in this model (1.02 (0.88-1.19)). Further adjustment for HOMA-S did not change these findings. Higher baseline 2hPG was more strongly associated with an increase in SBP than in DBP over 5 years. We conclude that higher 2hPG predicted future hypertension occurrence in this population.
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- 2007
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36. Region-specific transcriptional changes following the three antidepressant treatments electro convulsive therapy, sleep deprivation and fluoxetine
- Author
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Xiaoying Lu, Maria C. Morale, Graeme Bilbe, Alasdair M. Barr, Tamas Bartfai, Pietro Paolo Sanna, Rainer Maier, Bruno Conti, and Daniel Hoyer
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Male ,medicine.medical_specialty ,Transcription, Genetic ,medicine.medical_treatment ,Tritium ,Serotonergic ,Rats, Sprague-Dawley ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Electroconvulsive therapy ,Fluoxetine ,Internal medicine ,medicine ,Animals ,Electroconvulsive Therapy ,Neurotransmitter ,Molecular Biology ,In Situ Hybridization ,Oligonucleotide Array Sequence Analysis ,Brain Chemistry ,business.industry ,Genomics ,Rats ,Psychiatry and Mental health ,Endocrinology ,chemistry ,Receptor, Serotonin, 5-HT1A ,Antidepressive Agents, Second-Generation ,Autoradiography ,Sleep Deprivation ,Locus coeruleus ,Antidepressant ,Serotonin ,business ,Reuptake inhibitor ,medicine.drug - Abstract
The significant proportion of depressed patients that are resistant to monoaminergic drug therapy and the slow onset of therapeutic effects of the selective serotonin reuptake inhibitors (SSRIs)/serotonin/noradrenaline reuptake inhibitors (SNRIs) are two major reasons for the sustained search for new antidepressants. In an attempt to identify common underlying mechanisms for fast- and slow-acting antidepressant modalities, we have examined the transcriptional changes in seven different brain regions of the rat brain induced by three clinically effective antidepressant treatments: electro convulsive therapy (ECT), sleep deprivation (SD), and fluoxetine (FLX), the most commonly used slow-onset antidepressant. Each of these antidepressant treatments was applied with the same regimen known to have clinical efficacy: 2 days of ECT (four sessions per day), 24 h of SD, and 14 days of daily treatment of FLX, respectively. Transcriptional changes were evaluated on RNA extracted from seven different brain regions using the Affymetrix rat genome microarray 230 2.0. The gene chip data were validated using in situ hybridization or autoradiography for selected genes. The major findings of the study are: 1. The transcriptional changes induced by SD, ECT and SSRI display a regionally specific distribution distinct to each treatment. 2. The fast-onset, short-lived antidepressant treatments ECT and SD evoked transcriptional changes primarily in the catecholaminergic system, whereas the slow-onset antidepressant FLX treatment evoked transcriptional changes in the serotonergic system. 3. ECT and SD affect in a similar manner the same brain regions, primarily the locus coeruleus, whereas the effects of FLX were primarily in the dorsal raphe and hypothalamus, suggesting that both different regions and pathways account for fast onset but short lasting effects as compared to slow-onset but long-lasting effects. However, the similarity between effects of ECT and SD is somewhat confounded by the fact that the two treatments appear to regulate a number of transcripts in an opposite manner. 4. Multiple transcripts (e.g. brain-derived neurotrophic factor (BDNF), serum/glucocorticoid-regulated kinase (Sgk1)), whose level was reported to be affected by antidepressants or behavioral manipulations, were also found to be regulated by the treatments used in the present study. Several novel findings of transcriptional regulation upon one, two or all three treatments were made, for the latter we highlight homer, erg2, HSP27, the proto oncogene ret, sulfotransferase family 1A (Sult1a1), glycerol 3-phosphate dehydrogenase (GPD3), the orphan receptor G protein-coupled receptor 88 (GPR88) and a large number of expressed sequence tags (ESTs). 5. Transcripts encoding proteins involved in synaptic plasticity in the hippocampus were strongly affected by ECT and SD, but not by FLX. The novel transcripts, concomitantly regulated by several antidepressant treatments, may represent novel targets for fast onset, long-duration antidepressants.
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- 2006
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37. Cerebral cortical processing of swallowing in older adults
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Ravi S. Menon, Ruth E. Martin, Bradley J. MacIntosh, Todd K. Stevens, Amy M. Barr, Rebecca C. Smith, Vladimir Hachinski, Donald H. Taves, and Joseph S. Gati
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Cingulate cortex ,medicine.medical_specialty ,Audiology ,Lateralization of brain function ,Premotor cortex ,stomatognathic system ,Swallowing ,otorhinolaryngologic diseases ,medicine ,Humans ,Saliva ,Prefrontal cortex ,Anterior cingulate cortex ,Aged ,Aged, 80 and over ,Cerebral Cortex ,Brain Mapping ,medicine.diagnostic_test ,Postcentral gyrus ,General Neuroscience ,digestive, oral, and skin physiology ,Water ,Anatomy ,Middle Aged ,Magnetic Resonance Imaging ,Deglutition ,Oxygen ,medicine.anatomical_structure ,Data Interpretation, Statistical ,Female ,Psychology ,Functional magnetic resonance imaging - Abstract
While brain-imaging studies in young adults have implicated multiple cortical regions in swallowing, investigations in older subjects are lacking. This study examined the neural representations of voluntary saliva swallowing and water swallowing in older adults. Nine healthy females were examined with event-related functional magnetic resonance imaging (fMRI) while laryngeal swallow-related movements were recorded. Swallowing in the older adults, like young adults, activated multiple cortical regions, most prominently the lateral pericentral, perisylvian, and anterior cingulate cortex. Activation of the postcentral gyrus was lateralized to the left hemisphere for saliva and water swallowing, consistent with our findings in young female subjects. Comparison of saliva and water swallowing revealed a fourfold increase in the brain volume activated by the water swallow compared to the saliva swallow, particularly within the right premotor and prefrontal cortex. This task-specific activation pattern may represent a compensatory response to the demands of the water swallow in the face of age-related diminution of oral sensorimotor function.
- Published
- 2006
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38. Social capital—A potential tool for analysis of the relationship between ageing individuals and their social environment
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Felicity M. Barr and Cherry Russell
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Social reproduction ,Economic growth ,Health (social science) ,Public economics ,Individual capital ,Social transformation ,Social change ,Sociology ,Social engagement ,Social mobility ,Social capital ,Social status - Abstract
The concept of social capital has acquired some currency amongst policy analysts to refer to the social norms, networks and trust that facilitate co-operation and provision of mutual support within or between groups. As yet there is no agreed definition of the concept; however influential Australian policy bodies are developing measures to track changes in social capital and relate these to policy changes. Most research is concerned with exploration of the concept in locality-based communities and its application to developing societies. This paper reviews research undertaken in Australia and overseas to determine the elements of social capital that may have importance in relation to policy development in response to an ageing population. It concludes that the concept could be of considerable value in understanding the determinants of policy success or failure, but that further research is required to understand the nature of social capital as it relates to older people.
- Published
- 2006
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39. Oropharyngeal Stimulation with Air-Pulse Trains Increases Swallowing Frequency in Healthy Adults
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Ruth E. Martin, Amy M. Barr, Frank Bihari, and Julie A. Theurer
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Adult ,medicine.medical_specialty ,Oropharynx ,Stimulation ,Audiology ,Sensitivity and Specificity ,Cohort Studies ,Speech and Hearing ,stomatognathic system ,Swallowing ,Reference Values ,Physical Stimulation ,otorhinolaryngologic diseases ,Humans ,Medicine ,Latency (engineering) ,Sensory stimulation therapy ,business.industry ,Pulse (signal processing) ,digestive, oral, and skin physiology ,Gastroenterology ,Dysphagia ,Deglutition ,Otorhinolaryngology ,Anesthesia ,Female ,Perception ,Laryngeal Muscles ,medicine.symptom ,business ,Muscle Contraction - Abstract
This study sought to determine whether air-pulse trains delivered to the peritonsillar area would facilitate swallowing in healthy subjects. Trains of unilateral or bilateral air pulses were delivered to the peritonsillar area via tubing embedded in a dental splint, while swallows were simultaneously identified from their associated laryngeal and respiratory movements. Results from four subjects indicated that oropharyngeal air-pulse stimulation evoked an irrepressible urge to swallow, followed by an overt swallow as verified by laryngeal and respiratory movements. Moreover, air-pulse stimulation was associated with a significant increase in swallowing frequency. Mean latency of swallowing following bilateral stimulation tended to be less than the latency of swallowing following unilateral stimulation. These findings in healthy adults suggest the possibility that oropharyngeal air-pulse stimulation may have clinical utility in dysphagic individuals.
- Published
- 2005
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40. Triplet Morbidity and Mortality in a Large Case Series
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Martin Keszler, Sybil M. Barr, and Sarah H. Poggi
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Adult ,Male ,congenital, hereditary, and neonatal diseases and abnormalities ,Pediatrics ,medicine.medical_specialty ,Neonatal intensive care unit ,Adverse outcomes ,Birth weight ,Gestational Age ,macromolecular substances ,Cohort Studies ,Pregnancy ,Risk Factors ,Infant Mortality ,Humans ,Medicine ,Triplet birth ,Retrospective Studies ,Series (stratigraphy) ,Triplets ,Periventricular leukomalacia ,business.industry ,Infant, Newborn ,Pregnancy Outcome ,Obstetrics and Gynecology ,Gestational age ,Retinopathy of prematurity ,General Medicine ,Middle Aged ,medicine.disease ,Survival Analysis ,United States ,Intraventricular hemorrhage ,Hypospadias ,Necrotizing enterocolitis ,Pediatrics, Perinatology and Child Health ,Gestation ,Female ,Morbidity ,Pregnancy, Multiple ,business ,Selective fetal reduction ,Infant, Premature ,Maternal Age - Abstract
High-order multiple births have risen an estimated 400% in the past 2 decades, and the great majority of these are triplet births. Women 40 years of age and older are the most likely to have triplets. Both a trend to delay childbearing and the use of fertility-enhancing medications and procedures are responsible. Historically, triplet infants are at risk of adverse outcomes, but recent studies fail to demonstrate an inordinate number of poor outcomes. Since 1993, there have been 51 consecutive triplet births at the authors' institution, the number of infants totaling 153. The mean birth weight was 1789 g, and the mean gestational age was 32.6 weeks. More than one third of triplets were born at 34 to 36 weeks gestation (Fig. 1). Mean 1- and 5-minute Apgar scores were 7 and 9, respectively. Discordance was present in 17.6% of newborn infants. Three infants had congenital abnormalities; 2 had hypospadias and 1, a ventricular septal defect. Complications were infrequent. Chronic lung disease and necrotizing enterocolitis each were diagnosed in 3% of infants. There were no cases of intraventricular hemorrhage, periventricular leukomalacia, or advanced retinopathy of prematurity. The mean hospital stay was 23 days. All but 4% of infants survived to be discharged from the hospital. Excellent survival and a very low level of morbidity were observed in this large series of triplet births. The authors believe that it might not be necessary to offer selective fetal reduction when triplets are expected.
- Published
- 2003
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41. Altered immunoreactivity of complexin protein in prefrontal cortex in severe mental illness
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Clint E. Young, K Longworth, S. Takahashi, Ken Sawada, J. John Mann, Andrew J. Dwork, Alasdair M. Barr, Peter Falkai, Victoria Arango, William G. Honer, and Anthony G. Phillips
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Adult ,Male ,medicine.medical_specialty ,Psychosis ,Postmortem studies ,Central nervous system ,Prefrontal Cortex ,Nerve Tissue Proteins ,Rats, Sprague-Dawley ,Cellular and Molecular Neuroscience ,Reference Values ,Cause of Death ,Internal medicine ,medicine ,Haloperidol ,Animals ,Humans ,Prefrontal cortex ,Chlorpromazine ,Molecular Biology ,Aged ,Depressive Disorder ,biology ,Middle Aged ,medicine.disease ,Immunohistochemistry ,Rats ,Adaptor Proteins, Vesicular Transport ,Suicide ,Psychiatry and Mental health ,Endocrinology ,medicine.anatomical_structure ,Schizophrenia ,Synaptophysin ,biology.protein ,Regression Analysis ,Psychology ,Neuroscience ,medicine.drug - Abstract
Recent imaging and postmortem studies suggest that impaired connectivity is involved in the pathophysiology of schizophrenia and major affective disorders. We investigated the presynaptic proteins complexin (Cx) I and Cx II in postmortem prefrontal cortex in schizophrenia (n = 13; six suicide, seven nonsuicide), major depression (n= 11, all suicide) and controls (n = 11) with an enzyme-linked immunoadsorbent assay (ELISA). Overall analysis indicated a significant difference between groups (F = 3.93, P = 0.007). Cx I (enriched in inhibitory terminals) was decreased 33% in schizophrenia (26% in schizophrenia/nonsuicide, 42% in schizophrenia/suicide) and 27% in major depression. Cx II (enriched in excitatory terminals) was not significantly different. Analysis of the ratio of Cx II/Cx I was carried out as an indication of the balance of excitatory to inhibitory terminals. A significant difference between groups (ANOVA, F = 6.42, P = 0.005) was observed. The mean value of Cx II/Cx I was significantly increased by 34% in schizophrenia (26% in schizophrenia/nonsuicide and 43% in schizophrenia/suicide) and by 32% in depression compared with control (Student-Newman-Keuls test, P = 0.05). Immunoreactivities of the two complexins were highly correlated in all groups. However, compared with controls and depression, samples from cases with schizophrenia appeared to have relatively less Cx I for similar amounts of Cx II. Immunocytochemical studies of rat frontal cortex after 3 weeks treatment with chlorpromazine, trifluoperazine or haloperidol revealed no differences in complexins, synaptophysin, SNAP-25, syntaxin or VAMP in comparison with animals treated with vehicle. Alterations of complexins may contribute to the molecular substrate for abnormalities of neural connectivity in severe mental disorders.
- Published
- 2002
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42. Repeated electroconvulsive shock attenuates the depressive-like effects of d-amphetamine withdrawal on brain reward function in rats
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Athanasios P. Zis, Anthony G. Phillips, and Alasdair M. Barr
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Male ,Dextroamphetamine ,Lateral hypothalamus ,medicine.medical_treatment ,Electroconvulsive therapy ,Reward ,medicine ,Animals ,Rats, Long-Evans ,Amphetamine ,Pharmacology ,Electroshock ,Depression ,Kindling ,Brain ,Anhedonia ,Electric Stimulation ,Rats ,Substance Withdrawal Syndrome ,Anesthesia ,Endogenous depression ,Antidepressant ,Central Nervous System Stimulants ,Brain stimulation reward ,medicine.symptom ,Psychology ,medicine.drug - Abstract
Rationale: The withdrawal of humans from high doses of psychostimulant drugs can result in a transient syndrome which appears isomorphic to endogenous depression. One of the more prominent symptoms is a loss of hedonic capacity; in animals, the anhedonia associated with amphetamine withdrawal has been measured objectively by decrements in responding for intracranial self-stimulation (ICSS). Objective: To date, the effects of amphetamine withdrawal on ICSS responding have been reversed by different antidepressant drugs. In the present study, we sought to reverse withdrawal-induced anhedonia by administration of repeated electroconvulsive shocks (ECS). Methods: Rats with electrodes in the lateral hypothalamus were trained on an ascending-series current intensity ICSS paradigm until stable levels of responding were attained. Half of the animals were then administered a 4-day escalating dose schedule of d-amphetamine, and tests for ICSS responding started 12 h after the final injection. During withdrawal, all animals received daily treatment with either ECS or sham-ECS. Results: Amphetamine withdrawal was associated with reduced ICSS responding; animals treated with ECS exhibited a facilitated recovery compared to sham-ECS treated animals, and returned to control levels of ICSS responding 24 h earlier. Conclusions: ECS was able to mitigate the anhedonic effects of d-amphetamine withdrawal, and provides additional support for the use of psychostimulant withdrawal as a model of depression.
- Published
- 2001
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43. A polycystic kidney-disease gene homologue required for male mating behaviour in C. elegans
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Paul W. Sternberg and Maureen M. Barr
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Nervous system ,Genetics ,Multidisciplinary ,biology ,PKD1 ,urogenital system ,Sensory system ,biology.organism_classification ,medicine.disease ,Spicule insertion ,female genital diseases and pregnancy complications ,Sensory neuron ,medicine.anatomical_structure ,Hermaphrodite ,medicine ,Polycystic kidney disease ,Caenorhabditis elegans - Abstract
The stereotyped mating behaviour of the Caenorhabditis elegans male is made up of several substeps: response, backing, turning, vulva location, spicule insertion and sperm transfer. The complexity of this behaviour is reflected in the sexually dimorphic anatomy and nervous system. Behavioural functions have been assigned to most of the male-specific sensory neurons by means of cell ablations; for example, the hook sensory neurons HOA and HOB are specifically required for vulva location. We have investigated how sensory perception of the hermaphrodite by the C. elegans male controls mating behaviours. Here we identify a gene, lov-1 (for location of vulva), that is required for two male sensory behaviours: response and vulva location. lov-1 encodes a putative membrane protein with a mucin-like, serine–threonine-rich amino terminus followed by two blocks of homology to human polycystins, products of the autosomal dominant polycystic kidney-disease loci PKD1 and PKD2 (ref 4). LOV-1 is the closest C. elegans homologue of PKD1. lov-1 is expressed in adult males in sensory neurons of the rays, hook and head, which mediate response, vulva location, and potentially chemotaxis to hermaphrodites, respectively. PKD-2, the C. elegans homologue of PKD2, is localized to the same neurons as LOV-1, suggesting that they function in the same pathway.
- Published
- 1999
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44. Withdrawal following repeated exposure to d -amphetamine decreases responding for a sucrose solution as measured by a progressive ratio schedule of reinforcement
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Alasdair M. Barr and Anthony G. Phillips
- Subjects
Male ,Pharmacology ,Motivation ,Sucrose ,Dextroamphetamine ,Anhedonia ,Rats ,Substance Withdrawal Syndrome ,Regimen ,Self Stimulation ,Sucrose solution ,Toxicity ,medicine ,Animals ,Central Nervous System Stimulants ,Rats, Long-Evans ,Progressive ratio ,medicine.symptom ,Reinforcement ,Amphetamine ,Psychology ,Reinforcement, Psychology ,medicine.drug - Abstract
Numerous studies have shown that withdrawal from sustained high doses of psychostimulant drugs such as cocaine or d-amphetamine produces depressive-like symptoms in both rats and humans. The majority of experiments with rodents have assessed the effects of amphetamine withdrawal on reinforcing electrical self-stimulation in different brain regions, but relatively few have examined effects on responding for natural reinforcers. In the present study, two groups of mildly food and water deprived male rats were trained to respond on a lever for a 4% sucrose solution under a progressive ratio schedule of reinforcement. One group was subsequently administered a 4-day regimen of injections of increasing doses of d-amphetamine based on a schedule shown previously to reduce self-stimulation behaviour. Break points were significantly reduced for up to 4 days after the termination of drug administration, suggesting a decreased motivation to obtain the natural reward. A further experiment demonstrated that the identical drug regimen produced no effect upon consumption of the 4% sucrose solution when it was freely available. These results demonstrate that the progressive ratio procedure may be a useful technique for evaluating changes in motivation for natural reinforcing stimuli following withdrawal from psychostimulant drugs.
- Published
- 1999
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45. A retrospective study of antipsychotic drug switching in a pediatric population
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David Linton, Ric M. Procyshyn, Lik Hang Lee, Alasdair M. Barr, and Dean Elbe
- Subjects
Male ,Drug ,medicine.medical_specialty ,Adolescent ,Databases, Factual ,media_common.quotation_subject ,medicine.medical_treatment ,Drug Substitution ,Antipsychotic ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Child ,Psychiatry ,Children ,Retrospective Studies ,media_common ,Polypharmacy ,Risperidone ,business.industry ,Mental Disorders ,Medical record ,Retrospective cohort study ,030227 psychiatry ,3. Good health ,Psychiatry and Mental health ,Treatment Outcome ,Switching ,Emergency medicine ,Quetiapine ,Drug Therapy, Combination ,Female ,business ,030217 neurology & neurosurgery ,Research Article ,Antipsychotic Agents ,medicine.drug - Abstract
Background Antipsychotic drugs can be used to help treat a wide variety of psychiatric disorders. However, specific antipsychotic drugs for any particular patient may need to be changed for a number of different reasons, including a lack of therapeutic efficacy and / or intolerance to medication side-effects. Drug switching may occur through a limited number of established patterns. The nature of these changes is not well characterized in youth, despite their frequent occurrence. Methods A retrospective analysis of antipsychotic drug switches was conducted on patients who had been admitted as inpatients to a tertiary care child and adolescent psychiatric institute. PharmaNet (a large, central administrative database) records of all medications prescribed in the 52 weeks prior to admission, and then between admission and discharge, were analyzed for switching patterns. Additional data regarding diagnoses were obtained from medical chart review. Results Patients represented a diagnostically heterogeneous population, and almost all antipsychotic drugs were administered off-label. In the one year prior to and during admission to the hospital, a total of 31 out of 139 patients switched antipsychotic drugs. The frequency of switching increased closer to the time of admission, and the proportional rate of switching was even higher during hospital stay. The most common switch was from risperidone to quetiapine. Our analysis identified three main patterns of drug switching, all occurring with similar frequency: titrated drug switches, abrupt drug switches and concurrent drug administration. Conclusions The present study indicates that antipsychotic drug switching in youth may be relatively common, particularly in the year prior to hospitalization. No specific manner of drug switching predominates. This study also demonstrates the feasibility of using large administrative databases to characterise switching patterns in youth.
- Published
- 2013
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46. Proton decay and the origin of quark and lepton mixing
- Author
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Heng-Yu Chen and Stephen M. Barr
- Subjects
Physics ,Quark ,Nuclear and High Energy Physics ,Particle physics ,Proton decay ,High Energy Physics::Lattice ,High Energy Physics::Phenomenology ,FOS: Physical sciences ,Model parameters ,Fermion ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,High Energy Physics::Experiment ,Neutrino ,Lepton - Abstract
It was recently proposed that all flavor mixing has a single source, namely the mixing of the three quark and lepton families with "extra" vectorlike fermions in 5 + 5-bar multiplets of SU(5). This was shown to lead to several testable predictions including neutrino masses and CP-violating phases. Here it is shown that the mixing angles within grand unified fermion multiplets are also predicted. Proton decay branching ratios would thus give several independent tests of the model. Certain model parameters could be determined independently from the quark and lepton spectrum and from proton decay., Comment: 13 pages
- Published
- 2013
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47. A simple grand unified relation between neutrino mixing and quark mixing
- Author
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Heng-Yu Chen and Stephen M. Barr
- Subjects
Quark ,Physics ,Nuclear and High Energy Physics ,Particle physics ,Dirac (video compression format) ,High Energy Physics::Phenomenology ,FOS: Physical sciences ,Fermion ,Mass matrix ,High Energy Physics - Phenomenology ,Matrix (mathematics) ,High Energy Physics - Phenomenology (hep-ph) ,High Energy Physics::Experiment ,Neutrino ,Mixing (physics) ,Lepton - Abstract
It is proposed that all flavor mixing is caused by the mixing of the three quark and lepton families with vectorlike fermions in 5 + 5-bar multiplets of SU(5). This simple assumption implies that both V_{CKM} and U_{MNS} are generated by a single matrix. The entire 3-by-3 complex mass matrix of the neutrinos M_{nu} is then found to have a simple expression in terms of two complex parameters and an overall scale. Thus, all the presently unknown neutrino parameters are predicted. The best fits are for theta_{atm} less than or approximately 40 degrees. The leptonic Dirac CP phase is found to be somewhat greater than pi radians., Comment: 10 pages, 4 figures, one table. Typos corrected
- Published
- 2012
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48. Symposium Introduction
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Jason M Barr, Troy Tassier, and Leanne Ussher
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Economics and Econometrics - Published
- 2008
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49. Cognitive reserve, presynaptic proteins and dementia in the elderly
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Julie A. Schneider, Ken Sawada, Alasdair M. Barr, Martha Clare Morris, Allen E. Thornton, Sue Leurgans, David A. Bennett, and William G. Honer
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Male ,R-SNARE Proteins ,0302 clinical medicine ,Cognitive Reserve ,Reference Values ,Syntaxin ,Longitudinal Studies ,Cognitive reserve ,Aged, 80 and over ,Cerebral Cortex ,0303 health sciences ,Qa-SNARE Proteins ,Brain ,Cerebral Infarction ,Alzheimer's disease ,SNARE protein ,3. Good health ,Psychiatry and Mental health ,Schizophrenia ,complexin ,Original Article ,Female ,Psychology ,medicine.medical_specialty ,Synaptosomal-Associated Protein 25 ,Nerve Tissue Proteins ,Neuropathology ,Risk Assessment ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Atrophy ,Alzheimer Disease ,Internal medicine ,medicine ,Humans ,Dementia ,Cognitive Dysfunction ,Protein Interaction Domains and Motifs ,Biological Psychiatry ,Aged ,030304 developmental biology ,Membrane Proteins ,Odds ratio ,medicine.disease ,Adaptor Proteins, Vesicular Transport ,Endocrinology ,Synapses ,Neuroscience ,030217 neurology & neurosurgery ,dementia - Abstract
Differences in cognitive reserve may contribute to the wide range of likelihood of dementia in people with similar amounts of age-related neuropathology. The amounts and interactions of presynaptic proteins could be molecular components of cognitive reserve, contributing resistance to the expression of pathology as cognitive impairment. We carried out a prospective study with yearly assessments of N = 253 participants without dementia at study entry. Six distinct presynaptic proteins, and the protein-protein interaction between synaptosomal-associated protein 25 (SNAP-25) and syntaxin, were measured in post-mortem brains. We assessed the contributions of Alzheimer's disease (AD) pathology, cerebral infarcts and presynaptic proteins to odds of dementia, level of cognitive function and cortical atrophy. Clinical dementia was present in N = 97 (38.3%), a pathologic diagnosis of AD in N = 142 (56.1%) and cerebral infarcts in N = 77 (30.4%). After accounting for AD pathology and infarcts, greater amounts of vesicle-associated membrane protein, complexins I and II and the SNAP-25/syntaxin interaction were associated with lower odds of dementia (odds ratio = 0.36-0.68, P0.001 to P = 0.03) and better cognitive function (P0.001 to P = 0.03). Greater cortical atrophy, a putative dementia biomarker, was not associated with AD pathology, but was associated with lower complexin-II (P = 0.01) and lower SNAP-25/syntaxin interaction (P0.001). In conclusion, greater amounts of specific presynaptic proteins and distinct protein-protein interactions may be structural or functional components of cognitive reserve that reduce the risk of dementia with aging.
- Published
- 2012
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50. Segregation and Strategic Neighborhood Interaction
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M Barr, Jason, primary and Tassier, Troy, additional
- Published
- 2008
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