367 research outputs found

    Resistance spikes and domain wall loops in Ising quantum Hall ferromagnets

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    We explain the recent observation of resistance spikes and hysteretic transport properties in Ising quantum Hall ferromagnets in terms of the unique physics of their domain walls. Self-consistent RPA/Hartree-Fock theory is applied to microscopically determine properties of the ground state and domain-wall excitations. In these systems domain wall loops support one-dimensional electron systems with an effective mass comparable to the bare electron mass and may carry charge. Our theory is able to account quantitatively for the experimental Ising critical temperature and to explain characteristics of the resistive hysteresis loops.Comment: 4 pages, 3 figure

    Hepatitis C Infection Patterns at a Tertiary Care Center in New York: A Cross-Sectional Study.

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    Introduction In the United States, 2.7 to 3.9 million patients are infected with the hepatitis C virus (HCV) with 3,500 new cases reported yearly. According to the Centers for Disease Control and Prevention, HCV was the underlying or contributing cause of death of 19,659 patients in 2014. These facts underscore the need for a better understanding of the scope of this disease. Our epidemiologic study aimed at analyzing the pattern of occurrence of HCV infection at Staten Island University Hospital (SIUH) by evaluating the characteristics of newly infected patients with hepatitis C in 2014. The identified features served to better distinguish the targets for preventive health care in our particular population. Methodology A cross-sectional study of all newly diagnosed patients with HCV infections in the year 2014 presenting to SIUH was conducted using International Classification of Disease-9 codes (ICD-9) for hepatitis C. We included all patients with a positive HCV antibody confirmed by polymerase chain reaction testing. Patients were divided into groups according to age to simulate the age groups in the 2013 - 2014 Hepatitis B and C Annual Report of the New York City (NYC) Department of Health and Mental Hygiene published in 2016 (abbreviated to 2014 NYCDOH Report, hereafter). Gender and HCV genotypes were also collected. We compared disease frequency between age groups, gender, and genotype with the results of the 2014 NYCDOH Report. Results A total of 378 newly diagnosed HCV cases were identified; 60.05% were men, and 39.95% were women. The rate of infection with genotype 1a was the highest (36. 5%) followed by 1b (25.9%). In women, genotype 1b was predominant (13.76%) versus genotype 1a as the most common in men. The mean age was 54 years for men and 57 years for women. Most cases fell into the 60 to 69-year age group (32.28%), followed by the 50 to 59-year age group (31.48%). More so, all patients 80 years and older were exclusively women. Conclusions We found most new HCV infections at SIUH were diagnosed in patients aged 60 to 69 years, and the 2014 NYC DOH Report indicates most new HCV infections occur in patients aged 40 to 59 years. Also, all HCV infections detected in patients older than 80 years of age were found in women. These findings provide a better understanding of the patient demographics for appropriate HCV screening policies. Increased awareness and strict adherence to screening policies in baby boomers and high-risk populations are paramount in order to diagnose HCV infection early, offer therapy, and prevent HCV-related mortality and morbidity

    Highly Anisotropic Transport in the Integer Quantum Hall Effect

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    At very large tilt of the magnetic (B) field with respect to the plane of a two-dimensional electron system the transport in the integer quantum Hall regime at ν\nu = 4, 6, and 8 becomes strongly anisotropic. At these filling factors the usual {\em deep minima} in the magneto-resistance occur for the current flowing {\em perpendicular} to the in-plane B field direction but develop into {\em strong maxima} for the current flowing {\em parallel} to the in-plane B field. The origin of this anisotropy is unknown but resembles the recently observed anisotropy at half-filled Landau levels.Comment: 4 pages, 4 figure

    Clinicopathological evaluation of chronic traumatic encephalopathy in players of American football

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    IMPORTANCE: Players of American football may be at increased risk of long-term neurological conditions, particularly chronic traumatic encephalopathy (CTE). OBJECTIVE: To determine the neuropathological and clinical features of deceased football players with CTE. DESIGN, SETTING, AND PARTICIPANTS: Case series of 202 football players whose brains were donated for research. Neuropathological evaluations and retrospective telephone clinical assessments (including head trauma history) with informants were performed blinded. Online questionnaires ascertained athletic and military history. EXPOSURES: Participation in American football at any level of play. MAIN OUTCOMES AND MEASURES: Neuropathological diagnoses of neurodegenerative diseases, including CTE, based on defined diagnostic criteria; CTE neuropathological severity (stages I to IV or dichotomized into mild [stages I and II] and severe [stages III and IV]); informant-reported athletic history and, for players who died in 2014 or later, clinical presentation, including behavior, mood, and cognitive symptoms and dementia. RESULTS: Among 202 deceased former football players (median age at death, 66 years [interquartile range, 47-76 years]), CTE was neuropathologically diagnosed in 177 players (87%; median age at death, 67 years [interquartile range, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]), including 0 of 2 pre–high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 National Football League (99%) players. Neuropathological severity of CTE was distributed across the highest level of play, with all 3 former high school players having mild pathology and the majority of former college (27 [56%]), semiprofessional (5 [56%]), and professional (101 [86%]) players having severe pathology. Among 27 participants with mild CTE pathology, 26 (96%) had behavioral or mood symptoms or both, 23 (85%) had cognitive symptoms, and 9 (33%) had signs of dementia. Among 84 participants with severe CTE pathology, 75 (89%) had behavioral or mood symptoms or both, 80 (95%) had cognitive symptoms, and 71 (85%) had signs of dementia. CONCLUSIONS AND RELEVANCE: In a convenience sample of deceased football players who donated their brains for research, a high proportion had neuropathological evidence of CTE, suggesting that CTE may be related to prior participation in football.This study received support from NINDS (grants U01 NS086659, R01 NS078337, R56 NS078337, U01 NS093334, and F32 NS096803), the National Institute on Aging (grants K23 AG046377, P30AG13846 and supplement 0572063345-5, R01 AG1649), the US Department of Defense (grant W81XWH-13-2-0064), the US Department of Veterans Affairs (I01 CX001038), the Veterans Affairs Biorepository (CSP 501), the Veterans Affairs Rehabilitation Research and Development Traumatic Brain Injury Center of Excellence (grant B6796-C), the Department of Defense Peer Reviewed Alzheimer’s Research Program (grant 13267017), the National Operating Committee on Standards for Athletic Equipment, the Alzheimer’s Association (grants NIRG-15-362697 and NIRG-305779), the Concussion Legacy Foundation, the Andlinger Family Foundation, the WWE, and the NFL

    Interaction Effects in a One-Dimensional Constriction

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    We have investigated the transport properties of one-dimensional (1D) constrictions defined by split-gates in high quality GaAs/AlGaAs heterostructures. In addition to the usual quantized conductance plateaus, the equilibrium conductance shows a structure close to 0.7(2e2/h)0.7(2e^2/h), and in consolidating our previous work [K.~J. Thomas et al., Phys. Rev. Lett. 77, 135 (1996)] this 0.7 structure has been investigated in a wide range of samples as a function of temperature, carrier density, in-plane magnetic field B∥B_{\parallel} and source-drain voltage VsdV_{sd}. We show that the 0.7 structure is not due to transmission or resonance effects, nor does it arise from the asymmetry of the heterojunction in the growth direction. All the 1D subbands show Zeeman splitting at high B∥B_{\parallel}, and in the wide channel limit the gg-factor is ∣g∣≈0.4\mid g \mid \approx 0.4, close to that of bulk GaAs. As the channel is progressively narrowed we measure an exchange-enhanced gg-factor. The measurements establish that the 0.7 structure is related to spin, and that electron-electron interactions become important for the last few conducting 1D subbands.Comment: 8 pages, 7 figures (accepted in Phys. Rev. B

    Social media in health and care co-production

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    The future of health and care services in the EU faces the three challenges of the aging population, fiscal restriction, and social inclusion. Co-production offers ways to manage informal care resources to enable them to better cater to the growing needs of elderly people. Social Media (SM) are seen as a critical enabler of co-production. This study investigates SM as an enabler of co-production in health and care for elderly people and develops a typology of opportunities and limitations of SM in relation to health and care. The study considers how SM acts as an enabler of co-production in health and care by facilitating its four underlying principles: equality, diversity, accessibility, and reciprocity. Normalization Process Theory (NPT) provides the theoretical framework for this qualitative study. Eighteen semi-structured interviews and observation of the activities of 10 online groups and individuals provide the data for the thematically-analysed findings. The study findings show how different SM are used to enable co-production through coordination and communication across boundaries. SM connects carers, disseminates information and engages volunteers. However, many types of SM are only rarely used in this sector due to their limitations. Nevertheless, carers of elderly patients demonstrated interest in using systems to engage people in the shaping of services, the sharing of experiences and encouraging activities. The study findings point to distinct patterns of feature use by different people involved in the care of elderly people. This diversity makes possible the principles of co-production by offering equality among users, enabling diversity of use, making experiences accessible, and encouraging reciprocity in the sharing of knowledge and mutual support. Exploitation of common resources also may lead to new forms of competition and conflicts. These conflicts require better management to enhance the coordination of the common pool of resources. The study finds that SM can facilitate co-production by offering mechanisms for coordination of the common pool of carer resources. It also enables better management of activities amongst other actors (professionals, patients, voluntary organisations, etc.). The study also demonstrates that, despite the capabilities of SM in achieving coproduction, many applications (both general and healthcare-specific) are not used to their full potential. The study also explores new innovations in this field and why they have failed to deliver their intended services

    Plasmodium knowlesi Genome Sequences from Clinical Isolates Reveal Extensive Genomic Dimorphism.

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    Plasmodium knowlesi is a newly described zoonosis that causes malaria in the human population that can be severe and fatal. The study of P. knowlesi parasites from human clinical isolates is relatively new and, in order to obtain maximum information from patient sample collections, we explored the possibility of generating P. knowlesi genome sequences from archived clinical isolates. Our patient sample collection consisted of frozen whole blood samples that contained excessive human DNA contamination and, in that form, were not suitable for parasite genome sequencing. We developed a method to reduce the amount of human DNA in the thawed blood samples in preparation for high throughput parasite genome sequencing using Illumina HiSeq and MiSeq sequencing platforms. Seven of fifteen samples processed had sufficiently pure P. knowlesi DNA for whole genome sequencing. The reads were mapped to the P. knowlesi H strain reference genome and an average mapping of 90% was obtained. Genes with low coverage were removed leaving 4623 genes for subsequent analyses. Previously we identified a DNA sequence dimorphism on a small fragment of the P. knowlesi normocyte binding protein xa gene on chromosome 14. We used the genome data to assemble full-length Pknbpxa sequences and discovered that the dimorphism extended along the gene. An in-house algorithm was developed to detect SNP sites co-associating with the dimorphism. More than half of the P. knowlesi genome was dimorphic, involving genes on all chromosomes and suggesting that two distinct types of P. knowlesi infect the human population in Sarawak, Malaysian Borneo. We use P. knowlesi clinical samples to demonstrate that Plasmodium DNA from archived patient samples can produce high quality genome data. We show that analyses, of even small numbers of difficult clinical malaria isolates, can generate comprehensive genomic information that will improve our understanding of malaria parasite diversity and pathobiology

    Mathematics in Medical Diagnostics - 2022 Proceedings of the 4th International Conference on Trauma Surgery Technology

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    The 4th event of the Giessen International Conference Series on Trauma Surgery Technology took place on April, the 23rd 2022 in Warsaw, Poland. It aims to bring together practical application research, with a focus on medical imaging, and the TDA experts from Warsaw. This publication contains details of our presentations and discussions

    Physicochemical and biological characterization of chitosan-microRNA nanocomplexes for gene delivery to MCF-7 breast cancer cells

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    Cancer gene therapy requires the design of non-viral vectors that carry genetic material and selectively deliver it with minimal toxicity. Non-viral vectors based on cationic natural polymers can form electrostatic complexes with negatively-charged polynucleotides such as microRNAs (miRNAs). Here we investigated the physicochemical/biophysical properties of chitosan–hsa-miRNA-145 (CS–miRNA) nanocomplexes and the biological responses of MCF-7 breast cancer cells cultured in vitro. Self-assembled CS–miRNA nanocomplexes were produced with a range of (+/−) charge ratios (from 0.6 to 8) using chitosans with various degrees of acetylation and molecular weight. The Z-average particle diameter of the complexes was <200 nm. The surface charge increased with increasing amount of chitosan. We observed that chitosan induces the base-stacking of miRNA in a concentration dependent manner. Surface plasmon resonance spectroscopy shows that complexes formed by low degree of acetylation chitosans are highly stable, regardless of the molecular weight. We found no evidence that these complexes were cytotoxic towards MCF-7 cells. Furthermore, CS–miRNA nanocomplexes with degree of acetylation 12% and 29% were biologically active, showing successful downregulation of target mRNA expression in MCF-7 cells. Our data, therefore, shows that CS–miRNA complexes offer a promising non-viral platform for breast cancer gene therapy
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