1,617 research outputs found
The structure of the PapD-PapGII pilin complex reveals an open and flexible P5 pocket
P pili are hairlike polymeric structures that mediate binding of uropathogenic Escherichia coli to the surface of the kidney via the PapG adhesin at their tips. PapG is composed of two domains: a lectin domain at the tip of the pilus followed by a pilin domain that comprises the initial polymerizing subunit of the 1,000-plus-subunit heteropolymeric pilus fiber. Prior to assembly, periplasmic pilin domains bind to a chaperone, PapD. PapD mediates donor strand complementation, in which a beta strand of PapD temporarily completes the pilin domain's fold, preventing premature, nonproductive interactions with other pilin subunits and facilitating subunit folding. Chaperone-subunit complexes are delivered to the outer membrane usher where donor strand exchange (DSE) replaces PapD's donated beta strand with an amino-terminal extension on the next incoming pilin subunit. This occurs via a zip-in-zip-out mechanism that initiates at a relatively accessible hydrophobic space termed the P5 pocket on the terminally incorporated pilus subunit. Here, we solve the structure of PapD in complex with the pilin domain of isoform II of PapG (PapGIIp). Our data revealed that PapGIIp adopts an immunoglobulin fold with a missing seventh strand, complemented in parallel by the G1 PapD strand, typical of pilin subunits. Comparisons with other chaperone-pilin complexes indicated that the interactive surfaces are highly conserved. Interestingly, the PapGIIp P5 pocket was in an open conformation, which, as molecular dynamics simulations revealed, switches between an open and a closed conformation due to the flexibility of the surrounding loops. Our study reveals the structural details of the DSE mechanism
A Systematic Review of Mosquito Coils and Passive Emanators: Defining Recommendations for Spatial Repellency Testing Methodologies.
Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control
Comorbidades físicas e psicológicas antes e depois da cirurgia bariátrica : um estudo longitudinal
Introduction: Morbid obesity has multiple implications for
psychological and physical health. Bariatric surgery has been
selected as the treatment of choice for this chronic disease,
despite the controversial impact of the surgery on psychosocial
health. The objective of this study was to describe candidates
for bariatric surgery and analyze changes in weight, psychopathology,
personality, and health problems and complaints at
6- and 12- month follow-up assessments.
Methods: Thirty obese patients (20 women and 10 men) with a
mean age of 39.17±8.81 years were evaluated in different dimensions
before surgery and 6 and 12 months after the procedure.
Results: Six and 12 months after bariatric surgery, patients
reported significant weight loss and a significant reduction in
the number of health problems and complaints. The rates of
self-reported psychopathology were low before surgery, and
there were no statistically significant changes over time. The
conscientiousness, extraversion, and agreeableness dimensions
increased, but neuroticism and openness remained unchanged.
All changes had a medium effect size.
Conclusions: Our results suggest that patients experience
significant health improvements and some positive personality
changes after bariatric surgery. Even though these findings
underscore the role of bariatric surgery as a relevant treatment
for morbid obesity, more in-depth longitudinal studies
are needed to elucidate the evolution of patients after the
procedure.Introdução: A obesidade mórbida tem várias implicações para
a saúde psicológica e física. A cirurgia bariátrica tem sido o
tratamento de escolha para essa doença crônica, apesar da
controvérsia sobre o impacto da cirurgia na saúde psicossocial.
O objetivo deste estudo foi descrever candidatos a cirurgia bariátrica e analisar mudanças no peso, psicopatologia personalidade,
problemas e queixas de saúde desses pacientes em avaliações
realizadas 6 e 12 meses após a cirurgia.
Métodos: Trinta pacientes obesos (20 mulheres e 10 homens)
com idade média de 39,17±8,81 anos foram avaliados em diferentes
dimensões antes da cirurgia e 6 e 12 meses após.
Resultados: Aos 6 e 12 meses após a cirurgia bariátrica, os
pacientes relataram significativa perda de peso e significativa
redução no número de problemas e queixas de saúde. As taxas
de psicopatologia autorrelatada foram baixas antes da cirurgia e
não sofreram mudanças significativas com o tempo. As dimensões
conscienciosidade, extroversão e agradabilidade aumentaram,
mas o neuroticismo e a abertura permaneceram inalteradas.
Todas as mudanças apresentaram um tamanho de efeito médio.
Conclusões: Os nossos resultados sugerem que os pacientes
experimentam melhoras significativas em saúde e algumas mudanças
positivas de personalidade após a cirurgia bariátrica.
Embora esses achados reforcem o papel da cirurgia bariátrica
como um tratamento relevante para a obesidade mórbida, mais
estudos longitudinais e aprofundados são necessários para elucidar
a evolução dos pacientes após a realização do procedimento.(undefined
Depression in medical students: insights from a longitudinal study
Background: Factors associated with depression of medical students are poorly understood. The purpose of this study is to determine the prevalence of depression in medical students, its change during the course, if depression persists for affected students, what are the factors associated with depression and how these factors change over time.
Methods: A prospective, longitudinal observational study was conducted at the Medical School of the University of Minho, Portugal, between academic years 2009-2010 to 2012-2013. We included students who maintained their participation by annually completing a questionnaire including Beck Depression Inventory (BDI). Anxiety and burnout were assessed using the State Trait Anxiety Inventory and Maslach Burnout Inventory. Surveys on socio-demographic variables were applied to evaluate potential predictors, personal and academic characteristics and perceived difficulties. ANOVA with multiple comparisons were used to compare means of BDI score. The medical students were organized into subgroups by K-means cluster analyses. ANOVA mixed-design repeated measurement was performed to assess a possible interaction between variables associated with depression.
Results: The response rate was 84, 92, 88 and 81% for academic years 2009-2010, 2010-2011,2011-2012 and 2012/2013, respectively. Two hundred thirty-eight medical students were evaluated longitudinally. For depression the prevalence ranged from 21.5 to 12.7% (academic years 2009/2010 and 2012/2013). BDI scores decreased during medical school. 19.7% of students recorded sustained high BDI over time. These students had high levels of trait-anxiety and choose medicine for anticipated income and prestige, reported more relationship issues, cynicism, and decreased satisfaction with social activities. Students with high BDI scores at initial evaluation with low levels of trait-anxiety and a primary interest in medicine as a career tended to improve their mood and reported reduced burnout, low perceived learning problems and increased satisfaction with social activities at last evaluation. No difference was detected between men and women in the median BDI score over time.
Conclusions: Our findings suggest that personal factors (anxiety traits, medicine choice factors, relationship patterns and academic burnout) are relevant for persistence of high levels of BDI during medical training. Medical schools need to identity students who experience depression and support then, as early as possible, particularly when depression has been present over time.info:eu-repo/semantics/publishedVersio
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
Timed inhibition of CDC7 increases CRISPR-Cas9 mediated templated repair.
Repair of double strand DNA breaks (DSBs) can result in gene disruption or gene modification via homology directed repair (HDR) from donor DNA. Altering cellular responses to DSBs may rebalance editing outcomes towards HDR and away from other repair outcomes. Here, we utilize a pooled CRISPR screen to define host cell involvement in HDR between a Cas9 DSB and a plasmid double stranded donor DNA (dsDonor). We find that the Fanconi Anemia (FA) pathway is required for dsDonor HDR and that other genes act to repress HDR. Small molecule inhibition of one of these repressors, CDC7, by XL413 and other inhibitors increases the efficiency of HDR by up to 3.5 fold in many contexts, including primary T cells. XL413 stimulates HDR during a reversible slowing of S-phase that is unexplored for Cas9-induced HDR. We anticipate that XL413 and other such rationally developed inhibitors will be useful tools for gene modification
Stereoselective handling of perhexiline:Implications regarding accumulation within the human myocardium
Purpose: Perhexiline is a prophylactic anti-ischaemic agent with weak calcium antagonist effect which has been increasingly utilised in the management of refractory angina. The metabolic clearance of perhexiline is modulated by CYP2D6 metaboliser status and stereoselectivity. The current study sought to (1) determine whether the acute accumulation of perhexiline in the myocardium is stereoselective and (2) investigate the relationship between duration of short-term therapy and the potential stereoselective effects of perhexiline within myocardium. Method: Patients (n = 129) from the active arm of a randomised controlled trial of preoperative perhexiline in cardiac surgery were treated with oral perhexiline for a median of 9 days. Correlates of atrial and ventricular concentrations of enantiomers were sought via univariate followed by multivariate analyses. Results: Myocardial uptake of both (+) and (−) perhexiline was greater in ventricles than in atria, and there was more rapid clearance of (−) than (+) perhexiline. The main determinants of atrial uptake of both (+) and (−) perhexiline were the plasma concentrations [(+) perhexiline: β = −0.256, p = 0.015; (−) perhexiline: β = −0.347, p = 0.001] and patients’ age [(+) perhexiline: β = 0.300, p = 0.004; (−) perhexiline: β = 0.288, p = 0.005]. Atrial uptake of (+) enantiomer also varied directly with duration of therapy (β = 0.228, p = 0.025), while atrial uptake of (−) perhexiline varied inversely with simultaneous heart rate (β = −0.240, p = 0.015). Conclusion: (1) Uptake of both perhexiline enantiomers into atrium is greater with advanced age and displays evidence of both saturability and minor stereoselectivity. (2) Atrial uptake of (−) perhexiline may selectively modulate heart rate reduction
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Effect of spatial configuration of an extended nonlinear Kierstead-Slobodkin reaction-transport model with adaptive numerical scheme
In this paper, we consider the numerical simulations of an extended nonlinear form
of Kierstead-Slobodkin reaction-transport system in one and two dimensions. We
employ the popular fourth-order exponential time differencing Runge-Kutta (ETDRK4)
schemes proposed by Cox and Matthew (J Comput Phys 176:430-455,
2002), that was modified by Kassam and Trefethen (SIAM J Sci Comput 26:1214-1233,
2005), for the time integration of spatially discretized partial differential equations. We demonstrate
the supremacy of ETDRK4 over the existing exponential time differencing integrators
that are of standard approaches and provide timings and error comparison. Numerical
results obtained in this paper have granted further insight to the question "What is the
minimal size of the spatial domain so that the population persists?" posed by Kierstead
and Slobodkin (J Mar Res 12:141-147,
1953
), with a conclusive remark that the popula-
tion size increases with the size of the domain. In attempt to examine the biological
wave phenomena of the solutions, we present the numerical results in both one- and
two-dimensional space, which have interesting ecological implications. Initial data and
parameter values were chosen to mimic some existing patternsScopus 201
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