bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics and Establishment of Clostridium difficile Infection in the Murine Gastrointestinal Tract
Authors: Koenigsknecht Mark J. , Theriot Casey M. , Bergin Ingrid L. , Schumacher Cassie A. , Schloss Patrick D. , Young Vincent B. 
Published: December 2014

ABSTRACT

Clostridium difficile
infection (CDI) following antibiotic therapy is a major public health threat. While antibiotic disruption of the indigenous microbiota underlies the majority of cases of CDI, the early dynamics of infection in the disturbed intestinal ecosystem are poorly characterized. This study defines the dynamics of infection with
C. difficile
strain VPI 10463 throughout the gastrointestinal (GI) tract using a murine model of infection. After inducing susceptibility to
C. difficile
colonization via antibiotic administration, we followed the dynamics of spore germination, colonization, sporulation, toxin activity, and disease progression throughout the GI tract.
C. difficile
spores were able to germinate within 6 h postchallenge, resulting in the establishment of vegetative bacteria in the distal GI tract. Spores and cytotoxin activity were detected by 24 h postchallenge, and histopathologic colitis developed by 30 h. Within 36 h, all infected mice succumbed to infection. We correlated the establishment of infection with changes in the microbiota and bile acid profile of the small and large intestines. Antibiotic administration resulted in significant changes to the microbiota in the small and large intestines, as well as a significant shift in the abundance of primary and secondary bile acids.
Ex vivo
analysis suggested the small intestine as the site of spore germination. This study provides an integrated understanding of the timing and location of the events surrounding
C. difficile
colonization and identifies potential targets for the development of new therapeutic strategies.
AterDDomain-Encoding Gene (SCO2368) Is Involved in Calcium Homeostasis and Participates in Calcium Regulation of a DosR-Like Regulon in Streptomyces coelicolor
Authors: Daigle François , Lerat Sylvain , Bucca Giselda , Sanssouci Édith , Smith Colin P. , Malouin François , Beaulieu Carole 
Published: December 2014

ABSTRACTAlthoughStreptomyces coelicoloris not resistant to tellurite, it possesses several TerD domain-encoding (tdd) genes of unknown function. To elucidate the function oftdd8, the transcriptomes ofS. coelicolorstrain M145 and of atdd8deletion mutant derivative (the Δtdd8strain) were compared. Several orthologs ofMycobacterium tuberculosisgenes involved in dormancy survival were upregulated in the deletion mutant at the visual onset of prodiginine production. These genes are organized in a putative redox stress response cluster comprising two large loci. A binding motif similar to the dormancy survival regulator (DosR) binding site ofM. tuberculosishas been identified in the upstream sequences of most genes in these loci. A predicted role for these genes in the redox stress response is supported by the low NAD+/NADH ratio in the Δtdd8strain. ThisS. coelicolorgene cluster was shown to be induced by hypoxia and NO stress. While thetdd8deletion mutant (the Δtdd8strain) was unable to maintain calcium homeostasis in a calcium-depleted medium, the addition of Ca2+in Δtdd8culture medium reduced the expression of several genes of the redox stress response cluster. The results shown in this work are consistent with Tdd8 playing a significant role in calcium homeostasis and redox stress adaptation.
Birth weight and childhood wheezing disorders: a systematic review and meta-analysis
Authors: Mebrahtu Teumzghi F , Feltbower Richard G , Greenwood Darren C , Parslow Roger C 
Published: December 2014

BackgroundPrevious observational studies have claimed that birth weight and childhood wheezing disorders are associated although the results remained inconsistent. One systematic review and two systematic reviews that included meta-analyses reported inconsistent results. We aimed to conduct a systematic review and meta-analysis to investigate this.MethodsAn online search of published papers linking childhood asthma and wheezing disorders with birth weight up to February 2014 was carried out using EMBASE and Medline medical research databases. Summary ORs were estimated using random-effects models. Subgroup meta-analyses were performed to assess the robustness of risk associations and between-study heterogeneity.ResultsA total of 37 studies comprising 1 712 737 participants were included in our meta-analysis. The unadjusted summary ORs for risk of childhood wheezing disorders associated with low birth weight (<2.5 kg) were 1.60 (95% CI 1.39 to 1.85, p<0.001) and 1.37 (95% CI 1.05 to 1.79, p=0.02) when compared with ≥2.5 and 2.5–4.0 kg birthweight groups, respectively. The overall summary OR for high birth weight (>4 kg) as compared to the 2.5–4.0 kg birthweight group was 1.02 (95% CI 0.99 to 1.04, p=0.13). There was substantial heterogeneity in the unadjusted low birth weight risk estimates which was not accounted for by predefined study characteristics. There was no significant heterogeneity in the high birth weight risk estimates. There was some evidence of funnel plot asymmetry and small study effects in the low birth weight (2.5 vs ≥2.5 kg and <2.5 vs 2.5–4 kg) OR estimates.ConclusionsOur results suggest that low birth (<2.5 kg) is an independent risk factor for wheezing disorders during childhood and adolescence although there was substantial heterogeneity among the risk estimates. However, we found no significant association of high birth weight with wheezing disorders.
Is 6-month GRACE risk score a useful tool to predict stroke after an acute coronary syndrome?
Authors: Álvarez-Álvarez Belén , Raposeiras-Roubín Sergio , Abu-Assi Emad , Cambeiro-González Cristina , Gestal-Romaní Santiago , López-López Andrea , Bouzas-Cruz Noelia , Castiñeira-Busto María , Saidhodjayeva Ozoda , Redondo-Diéguez Alfredo , Pereira López Eva , García-Acuña José María , González-Juanatey José Ramón 
Published: December 2014

ObjectivesThe risk of stroke after an acute coronary syndrome (ACS) has increased. The aim of this study was to do a comparative validation of the 6-month GRACE (Global Registry of Acute Coronary Events) risk score and CH2DS2VASc risk score to predict the risk of post-ACS ischaemic stroke.MethodsThis was a retrospective study carried out in a single centre with 4229 patients with ACS discharged between 2004 and 2010 (66.9±12.8 years, 27.9% women, 64.2% underwent percutaneous coronary intervention). The primary end point is the occurrence of an ischaemic stroke during follow-up (median 4.6 years, IQR 2.7–7.1 years).Results184 (4.4%) patients developed an ischaemic stroke; 153 (83.2%) had sinus rhythm and 31 (16.9%) had atrial fibrillation. Patients with stroke were older, with higher rates of hypertension, diabetes, previous stroke and previous coronary artery disease. The HR for CHA2DS2VASc was 1.36 (95% CI, 1.27 to 1.48, p<0.001) and for GRACE, HR was 1.02(95% CI, 1.01 to 1.03, p<0.001). Both risk scores show adequate discriminative ability (c-index 0.63±0.02 and 0.60±0.02 for CHA2DS2VASc and GRACE, respectively). In the reclassification method there was no difference (Net Reclassification Improvement 1.98%, p=0.69). Comparing moderate-risk/high-risk patients with low-risk patients, both risk scores showed very high negative predictive value (98.5% for CHA2DS2VASc, 98.1% for GRACE). The sensitivity of CHA2DS2VASc score was higher than the GRACE risk score (95.1% vs 87.0%), whereas specificity was lower (14.4% vs 30.2%).ConclusionsThe 6-month GRACE model is a clinical risk score that facilitates the identification of individual patients who are at high risk of ischaemic stroke after ACS discharge.
Gender-related associations of genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase and bradykinin B2 receptor with treadmill exercise test responses
Authors: Nunes Rafael Amorim Belo , Barroso Lúcia Pereira , Pereira Alexandre da Costa , Krieger José Eduardo , Mansur Alfredo José 
Published: December 2014

BackgroundTreadmill exercise test responses have been associated with cardiovascular prognosis in individuals without overt heart disease. Neurohumoral and nitric oxide responses may influence cardiovascular performance during exercise testing. Therefore, we evaluated associations between functional genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase, bradykinin receptor B2 and treadmill exercise test responses in men and women without overt heart disease.MethodsWe enrolled 766 (417 women; 349 men) individuals without established heart disease from a check-up programme at the Heart Institute, University of São Paulo Medical School. Exercise capacity, chronotropic reserve, maximum heart-rate achieved, heart-rate recovery, exercise systolic blood pressure (SBP), exercise diastolic blood pressure (DBP) and SBP recovery were assessed during exercise testing. Genotypes for the α-adrenergic receptors ADRA1A Arg347Cys (rs1048101), ADRA2A 1780 C>T (rs553668), ADRA2B Del 301–303 (rs28365031), endothelial nitric synthase (eNOS) 786 T>C (rs2070744), eNOS Glu298Asp (rs1799983) and BK2R (rs5810761) polymorphisms were assessed by PCR and high-resolution melting analysis.ResultsMaximum SBP was associated with ADRA1A rs1048101 (p=0.008) and BK2R rs5810761 (p=0.008) polymorphisms in men and ADRA2A rs553668 (p=0.008) and ADRA2B rs28365031 (p=0.022) in women. Maximum DBP pressure was associated with ADRA2A rs553668 (p=0.002) and eNOS rs1799983 (p=0.015) polymorphisms in women. Exercise capacity was associated with eNOS rs2070744 polymorphisms in women (p=0.01) and with eNOS rs1799983 in men and women (p=0.038 and p=0.024).ConclusionsThe findings suggest that genetic variants of α-adrenergic receptors and bradykinin B2 receptor may be involved with blood pressure responses during exercise tests. Genetic variants of endothelial nitric oxide synthase may be involved with exercise capacity and blood pressure responses during exercise tests. These responses may be gender-related.
The features of infrared spectrum of bio-polymer and its theoretical investigation
Authors: Pang Xiao-Feng 
Published: December 2014

We have here an insight into the features of molecular structures of bio-polymers with α-helix structure using infrared spectrum and elucidated theoretically, its relationship with bio-functions. In this case, we analyzed first the features of molecular structure of collagen and collected further the infrared spectrum of absorption of collagen and bovine serum albumin containing α-helix conformation in 400–4000 cm-1 as well as their changes of strength of infrared absorption with varying temperatures using Fourier Transform–Infrared (FT-IR) spectrometers in the region of 15–95°C. The results show that there is a new band of 1650 cm-1 close to the amide-I band of 1666 cm-1 or 1670 cm-1 in these bio-polymers, its strength decreases exponentially with increasing temperature of the systems, which can be expressed by exp [-(0.437 + 8.987 × 10-6 T 2)], but 1666 cm-1 band increases linearly with increasing temperature. We calculated the energy spectrum of the protein molecules with α-helix conformation using the Soliton Theory of bio-energy transport, which are basically same with the experimental results measured by us. From these results and soliton theory we can conclude that the nonlinear soliton excitation, corresponding to 1650 cm-1 band and the exciton excitation, is related to 1666 cm-1 band, exists in the collagen and bovine serum albumin. In the meanwhile, these results also verified that the soliton theory of bio-energy transport along α-helix bio-polymers is appropriate to the protein molecules with α-helix conformation. Therefore, the studied results are helpful to elucidate the relationship between the molecular structure and bio-function of these bio-polymers.
Sound Synthesis of a Gaussian Quantum Particle in an Infinite Square
Well
Authors: Cádiz Rodrigo F. , Ramos Javier 
Published: December 2014

Abstract
This article describes a synthesis technique based on the sonification of the dynamic behavior of a quantum particle enclosed in an infinite square well. More specifically, we sonify the momentum distribution of a one-dimensional Gaussian bouncing wave packet model. We have chosen this particular case because of its relative simplicity and interesting dynamic behavior, which makes it suitable for a novel sonification mapping that can be applied to standard synthesis techniques, resulting in the generation of appealing sounds. In addition, this sonification might provide useful insight into the behavior of the quantum particle. In particular, this model exhibits quantum revivals, minimizes uncertainty, and exhibits similarities to the case of a classical bouncing ball. The proposed model has been implemented in real time in both the Max/MSP and the Pure Data environments. The algorithm is based on concepts of additive synthesis where each oscillator describes the eigenfunctions that characterize the state evolution of the wave packet. We also provide an analysis of the sounds produced by the model from both a physical and a perceptual point of view.
New species of Centroderes (Kinorhyncha: Cyclorhagida) from the Northwest Atlantic Ocean, life cycle, and ground pattern of the genus
Authors: NEUHAUS BIRGER , PARDOS FERNANDO , SØRENSEN MARTIN V. , HIGGINS ROBERT P. 
Published: December 2014

Four new species of Centroderes are described from the Northwest Atlantic Ocean based on light microscopical observations of 153 adult and 26 juvenile specimens and on SEM investigations of 54 adult and 3 juvenile specimens. Centroderes barbanigra n. sp. and C. bonnyae n. sp. can be distinguished from all other species by the existence of a short lateroventral tube on segment 7. The latter species can be separated from the former by an acicular spine in the lateral accessory position on segment 8. The female of both C. readae n. sp. and C. spinosus possesses a female-specific, modified gland cell outlet on segments 7−9, but such an outlet is missing on segment 7 of all other species. The latter species is distinguished from the former by its robust lateroventral spine on segment 8 and by its lack of a laterodorsal sensory spot on segment 4, whereas the former species shows a midlateral sensory spot on segment 8. Centroderes drakei n. sp. agrees with the remaining American species in the possession of a laterodorsal sensory spot on segment 4; the former species can be distinguished from C. readae n. sp. by the lack of a sensory spot sublaterally on segment 1 and midlaterally on segment 8 as well as by the lack of a female-specific, modified gland cell outlet on segment 7; C. drakei n. sp. can be separated from C. barbanigra n. sp. and C. bonnyae n. sp. by its lack of a lateroventral tube on segment 7. We report anomalies rarely noticed for Kinorhyncha, such as different developmental artifacts in several specimens and a potential tumour in one individual. Evidence is provided that species of Centroderes develop via at least two adult life history stages, but three or more adult stages exist in C. drakei n. sp.; this represents the first record of a more complicated life cycle in Kinorhyncha. This paper also contains the first report of spermatophores in cyclorhagid Kinorhyncha and in both female and male specimens. In addition, characters in the ground pattern of Centroderes are summarized.
The Effect of Global Warming on Severe Thunderstorms in the United States
Authors: Seeley Jacob T. , Romps David M. 
Published: December 2014

Abstract
How will warming temperatures influence thunderstorm severity? This question can be explored by using climate models to diagnose changes in large-scale convective instability (CAPE) and wind shear, conditions that are known to be conducive to the formation of severe thunderstorms. First, an ensemble of climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) is evaluated on its ability to reproduce a radiosonde climatology of such storm-favorable conditions in the current climate’s spring and summer seasons, focusing on the contiguous United States (CONUS). Of the 11 climate models evaluated, a high-performing subset of four (GFDL CM3, GFDL-ESM2M, MRI-CGCM3, and NorESM1-M) is identified. Second, the twenty-first-century changes in the frequency of environments favorable to severe thunderstorms are calculated in these high-performing models as they are forced by the RCP4.5 and RCP8.5 emissions pathways. For the RCP8.5 scenario, the models predict consistent CONUS-mean fractional springtime increases in the range of 50%–180% by the end of the twenty-first century; for the summer, three of the four models predict increases in the range of 40%–120% and one model predicts a small decrease. This disagreement between the models is traced to divergent projections for future CAPE and boundary layer humidity in the Great Plains. This paper also explores the sensitivity of the results to the relative weight given to wind shear in determining how “favorable” a large-scale environment is for the development of severe thunderstorms, and it is found that this weighting is not the dominant source of uncertainty in projections of future thunderstorm severity.
Clinical Characteristics of Patients With Abnormal Ocular/Cervical Vestibular Evoked Myogenic Potentials in the Presence of Normal Caloric Responses
Authors: Iwasaki Shinichi , Fujimoto Chisato , Kinoshita Makoto , Kamogashira Teru , Egami Naoya , Yamasoba Tatsuya 
Published: December 2014

Objective: To investigate the clinical features and vestibular symptoms of patients with abnormal ocular vestibular evoked myogenic potentials (oVEMPs) and/or cervical VEMPs (cVEMPs) in the presence of normal caloric responses. Study Design: Retrospective chart review. Setting: Tertiary referral center. Methods: One thousand five hundred twenty-one consecutive patients with balance problems who underwent the caloric, cVEMP, and oVEMP tests were included, and patients who showed abnormal oVEMPs and/or cVEMPs in the presence of normal caloric responses were selected. Clinical characteristics, diagnoses, and vestibular symptoms of the patients were analyzed. Results: Of the 1521 patients, 227 (15%) were found to have abnormal oVEMPs and/or cVEMP responses with normal caloric responses. Benign paroxysmal positional vertigo (BBPV), Meniere’s disease, and vestibular migraine were the common diagnoses of these patients. Eighty-one patients (36%) could not be diagnosed with a recognizable disease. Multiple episodes of spinning vertigo with a duration of seconds to hours were their most common vestibular symptoms. Conclusion: BPPV, Meniere’s disease, and vestibular migraine are the most frequent diagnoses showing abnormal oVEMP and/or cVEMPs without canal paresis. Apart from these clinical entities, a portion of undiagnosed patients with multiple episodes of vertigo might have a disease that involves the otolith organs only.
Instrumented Mouthguard Acceleration Analyses for Head Impacts in Amateur Rugby Union Players Over a Season of Matches
Authors: King Doug , Hume Patria A. , Brughelli Matt , Gissane Conor 
Published: December 2014

Background: Direct impacts with the head (linear acceleration or pressure) and inertial loading of the head (rotational acceleration or strain) have been postulated as the 2 major mechanisms of head-related injuries such as concussion. Although data are accumulating for soccer and American football, there are no published data for nonhelmeted collision sports such as rugby union. Purpose: To quantify head impacts via instrumented mouthguard acceleration analyses for rugby union players over a season of matches. Study Design: Descriptive epidemiology study. Methods: Data on impact magnitude and frequency were collected with molded instrumented mouthguards worn by 38 premier amateur senior rugby players participating in the 2013 domestic season of matches. Results: A total of 20,687 impacts >10 g (range, 10.0-164.9 g) were recorded over the duration of the study. The mean ± SD number of impacts per player over the duration of the season of matches was 564 ± 618, resulting in a mean ± SD of 95 ± 133 impacts to the head per player, per match over the duration of the season of matches. The impact magnitudes for linear accelerations were skewed to the lower values ( Sp = 3.7 ± 0.02; P < .001), with a mean linear acceleration of 22.2 ± 16.2 g. Rotational accelerations were also skewed to the lower values ( Sp = 2.0 ± 0.02; P < .001), with a mean rotational acceleration of 3902.9 ± 3948.8 rad/s2. Conclusion: The acceleration magnitudes and number of head impacts in amateur rugby union players over a season of matches, measured via instrumented mouthguard accelerations, were higher than for most sports previously reported. Mean linear acceleration measured over a season of matches was similar to the mean linear accelerations previously reported for youth, high school, and collegiate American football players but lower than that for female youth soccer players. Mean rotational acceleration measured over a season of matches was similar to mean rotational accelerations for youth, high school, and collegiate American football players but less than those for female youth soccer players, concussed American collegiate players, collegiate American football players, and professional American football players.
Genetic and environmental determinants of 25-hydroxyvitamin D levels in multiple sclerosis
Authors: Laursen Julie H , Søndergaard Helle Bach , Albrechtsen Anders , Frikke-Schmidt Ruth , Koch-Henriksen Nils , Soelberg Sørensen Per , Sellebjerg Finn , Oturai Annette 
Published: December 2014

Background: Evidence is accumulating supporting a beneficial effect of vitamin D in multiple sclerosis (MS). Genome-wide association studies (GWAS) have shown significant associations between 25-hydroxyvitamin D (25(OH)D) and single nucleotide polymorphisms (SNPs) in key genes in the vitamin D metabolism. Objective: To examine the association between 25(OH)D and six GWAS SNPs and environmental factors in 1497 MS patients. Methods: Blood samples and lifestyle questionnaires were collected between 2009 and 2012. Genotyping of GC-, CYP2R1- and NADSYN1-SNPs was performed by TaqMan allelic discrimination (Life Technologies). Results: We found significant associations between 25(OH)D and SNPs in GC (rs7041, p = 0.01 and rs2282679, p = 0.03) and CYP2R1 (rs10741657, p =1.8 × 10−4). Season of blood sampling (p = 2.8 × 10−31), sex ( p = 1.9 × 10−5), BMI ( p = 2.3 × 10−5), vitamin supplements ( p = 7.0 × 10−22), and fish intake ( p = 0.02) also had significant effects on 25(OH)D. Conclusion: In this cross-sectional study, we found significant effects of environmental factors and SNPs in GC and CYP2R1 on 25(OH)D in MS patients. Since 25(OH)D might have protective effects in MS, and vitamin D supply is a modifiable factor, it may be important to include this in the MS treatment regimen.