49 research outputs found
Bott--Kitaev periodic table and index theory
We consider topological insulators and superconductors with discrete
symmetries and clarify the relevant index theory behind the periodic table
proposed by Kitaev.
An effective Hamiltonian determines the analytical index, which can be
computed by a topological index. We focus on the spatial dimensions one, two
and three, and only consider the bulk theory.
In two dimensions, the -valued invariants are given by the first
Chern number. Meanwhile, -valued invariants can be computed by
the odd topological index and its variations.
The Bott-Kitaev periodic table is well-known in the physics literature, we
organize the topological invariants in the framework of KR-theory.Comment: 37 page
The Role of Imaging in Patient Selection, Preoperative Planning, and Postoperative Monitoring in Human Upper Extremity Allotransplantation
Objective. To describe the role of imaging in vascular composite allotransplantation based on one institutionâs experience with upper extremity allotransplant patients. Methods. The institutional review board approved this review of HIPAA-compliant patient data without the need for individual consent. A retrospective review was performed of imaging from 2008 to 2011 on individuals undergoing upper extremity transplantation. This demonstrated that, of the 19 patients initially considered, 5 patients with a mean age of 37 underwent transplantation. Reports were correlated clinically to delineate which preoperative factors lead to patient selection versus disqualification and what concerns dictated postoperative imaging. Findings were subdivided into musculoskeletal and vascular imaging criterion. Results. Within the screening phase, musculoskeletal exclusion criterion included severe shoulder arthropathy, poor native bone integrity, and marked muscular atrophy. Vascular exclusion criterion included loss of sufficient arterial or venous supply and significant distortion of the native vascular architecture. Postoperative imaging was used to document healing and hardware integrity. Postsurgical angiography and ultrasound were used to monitor for endothelial proliferation or thrombosis as signs of rejection and vascular complication. Conclusion. Multimodality imaging is an integral component of vascular composite allotransplantation surgical planning and surveillance to maximize returning form and functionality while minimizing possible complications
Design of Personal Health Libraries for People Returning from Incarceration in the United States
A Comparison of Mindfulness, Nonjudgmental, and Cognitive Dissonance-Based Approaches to Mirror Exposure
This study compares different versions of mirror exposure (ME), a body image intervention with research support. ME protocols were adapted to maximize control and comparability, and scripted for delivery by research assistants. Female undergraduates (N = 168) were randomly assigned to receive mindfulness-based (MB; n = 58), nonjudgmental (NJ; n = 55), or cognitive dissonance-based (CD, n = 55) ME. Participants completed the Body Image Avoidance Questionnaire (BIAQ), Body Checking Questionnaire (BCQ), Satisfaction with Body Parts Scale (SBPS), Beck Depression Inventory-II (BDI-II), and Eating Disorders Examination Questionnaire (EDE-Q) at pre-treatment, post-treatment, and 1-month follow-up. Mixed models ANOVAs revealed a significant main effect of time on all measures, and no significant time by condition interaction for any measures except the SBPS. Post-hoc analysis revealed that only CD ME significantly improved SBPS outcome. Results suggest that all versions of ME reduce eating disorder risk factors, but only CD ME improves body satisfaction
Analysis of Nigerians with Apparently Sporadic Parkinson Disease for Mutations in LRRK2, PRKN and ATXN3
Several genetic variations have been associated with Parkinson disease in different populations over the past few years. Although a considerable number of worldwide populations have been screened for these variants, results from Sub-Saharan populations are very scarce in the literature. In the present report we have screened a cohort of Parkinson disease patients (nâ=â57) and healthy controls (nâ=â51) from Nigeria for mutations in the genes PRKN, LRRK2 and ATXN3. No pathogenic mutations were found in any of the genes. Hence, common pathogenic mutations in these genes, observed in several different populations, are not a frequent cause of Parkinson disease in Nigeria
An HST/COS Survey of the Low-Redshift IGM. I. Survey, Methodology, & Overall Results
We use high-quality, medium-resolution {\it Hubble Space Telescope}/Cosmic
Origins Spectrograph (\HST/COS) observations of 82 UV-bright AGN at redshifts
to construct the largest survey of the low-redshift
intergalactic medium (IGM) to date: 5343 individual extragalactic absorption
lines in HI and 25 different metal-ion species grouped into 2610 distinct
redshift systems at covering total redshift pathlengths and . Our semi-automated line-finding and
measurement technique renders the catalog as objectively-defined as possible.
The cumulative column-density distribution of HI systems can be parametrized
, with and
. This distribution is seen to evolve both in amplitude,
, and slope for .
We observe metal lines in 427 systems, and find that the fraction of IGM
absorbers detected in metals is strongly dependent on N_{HI}. The distribution
of OVI absorbers appear to evolve in the same sense as the Lya forest. We
calculate contributions to from different components of the low-
IGM and determine the Lya decrement as a function of redshift. IGM absorbers
are analyzed via a two-point correlation function (TPCF) in velocity space. We
find substantial clustering of \HI\ absorbers on scales of
km/s with no significant clustering at km/s. Splitting the
sample into strong and weak absorbers, we see that most of the clustering
occurs in strong, , metal-bearing IGM systems. The
full catalog of absorption lines and fully-reduced spectra is available via
MAST as a high-level science product at http://archive.stsci.edu/prepds/igm/.Comment: This is the accepted version (v3) of the paper. Previous versions
(July 2015 and Feb. 2014) should be replaced by this one. In particular,
please note that the associated MAST high-level-science product has been
updated to reflect the of the final state of the paper. It is available at:
http://archive.stsci.edu/prepds/igm
Global Regulatory Functions of the Staphylococcus aureus Endoribonuclease III in Gene Expression
RNA turnover plays an important role in both virulence and adaptation to stress in the Gram-positive human pathogen Staphylococcus aureus. However, the molecular players and mechanisms involved in these processes are poorly understood. Here, we explored the functions of S. aureus endoribonuclease III (RNase III), a member of the ubiquitous family of double-strand-specific endoribonucleases. To define genomic transcripts that are bound and processed by RNase III, we performed deep sequencing on cDNA libraries generated from RNAs that were co-immunoprecipitated with wild-type RNase III or two different cleavage-defective mutant variants in vivo. Several newly identified RNase III targets were validated by independent experimental methods. We identified various classes of structured RNAs as RNase III substrates and demonstrated that this enzyme is involved in the maturation of rRNAs and tRNAs, regulates the turnover of mRNAs and non-coding RNAs, and autoregulates its synthesis by cleaving within the coding region of its own mRNA. Moreover, we identified a positive effect of RNase III on protein synthesis based on novel mechanisms. RNase IIIâmediated cleavage in the 5âČ untranslated region (5âČUTR) enhanced the stability and translation of cspA mRNA, which encodes the major cold-shock protein. Furthermore, RNase III cleaved overlapping 5âČUTRs of divergently transcribed genes to generate leaderless mRNAs, which constitutes a novel way to co-regulate neighboring genes. In agreement with recent findings, low abundance antisense RNAs covering 44% of the annotated genes were captured by co-immunoprecipitation with RNase III mutant proteins. Thus, in addition to gene regulation, RNase III is associated with RNA quality control of pervasive transcription. Overall, this study illustrates the complexity of post-transcriptional regulation mediated by RNase III
Genome-Wide Association Study of White Blood Cell Count in 16,388 African Americans: the Continental Origins and Genetic Epidemiology Network (COGENT)
Total white blood cell (WBC) and neutrophil counts are lower among individuals of African descent due to the common African-derived ânullâ variant of the Duffy Antigen Receptor for Chemokines (DARC) gene. Additional common genetic polymorphisms were recently associated with total WBC and WBC sub-type levels in European and Japanese populations. No additional loci that account for WBC variability have been identified in African Americans. In order to address this, we performed a large genome-wide association study (GWAS) of total WBC and cell subtype counts in 16,388 African-American participants from 7 population-based cohorts available in the Continental Origins and Genetic Epidemiology Network. In addition to the DARC locus on chromosome 1q23, we identified two other regions (chromosomes 4q13 and 16q22) associated with WBC in African Americans (P<2.5Ă10â8). The lead SNP (rs9131) on chromosome 4q13 is located in the CXCL2 gene, which encodes a chemotactic cytokine for polymorphonuclear leukocytes. Independent evidence of the novel CXCL2 association with WBC was present in 3,551 Hispanic Americans, 14,767 Japanese, and 19,509 European Americans. The index SNP (rs12149261) on chromosome 16q22 associated with WBC count is located in a large inter-chromosomal segmental duplication encompassing part of the hydrocephalus inducing homolog (HYDIN) gene. We demonstrate that the chromosome 16q22 association finding is most likely due to a genotyping artifact as a consequence of sequence similarity between duplicated regions on chromosomes 16q22 and 1q21. Among the WBC loci recently identified in European or Japanese populations, replication was observed in our African-American meta-analysis for rs445 of CDK6 on chromosome 7q21 and rs4065321 of PSMD3-CSF3 region on chromosome 17q21. In summary, the CXCL2, CDK6, and PSMD3-CSF3 regions are associated with WBC count in African American and other populations. We also demonstrate that large inter-chromosomal duplications can result in false positive associations in GWAS
Modeling the Dynamic Transmission of Dengue Fever: Investigating Disease Persistence
Dengue is the most rapidly spreading mosquito-borne viral disease in the world and approximately 2.5 billion people live in dengue endemic countries. In Brazil it is mainly transmitted by Aedes aegypti mosquitoes. The wide clinical spectrum ranges from asymptomatic infections or mild illness, to the more severe forms of infection such as dengue hemorrhagic fever or dengue shock syndrome. The spread and dramatic increase in the occurrence of dengue cases in tropical and subtropical countries has been blamed on uncontrolled urbanization, population growth and international traveling. Vaccines are under development and the only current disease control strategy is trying to keep the vector quantity at the lowest possible levels. Mathematical models have been developed to help understand the disease's epidemiology. These models aim not only to predict epidemics but also to expand the capacity of phenomena explanation. We developed a spatially explicit model to simulate the dengue transmission in a densely populated area. The model involves the dynamic interactions between humans and mosquitoes and takes into account human mobility as an important factor of disease spread. We investigated the importance of human population size, human renewal rate, household infestation and ratio of vectors per person in the maintenance of sustained viral circulation
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570