bluuebunny/crossref_metadata_2025_split huggingface dataset:
Longitudinal Investigation of Carriage Rates, Counts, and Genotypes of Toxigenic Clostridium difficile in Early Infancy
Authors: Kubota Hiroyuki , Makino Hiroshi , Gawad Agata , Kushiro Akira , Ishikawa Eiji , Sakai Takafumi , Akiyama Takuya , Matsuda Kazunori , Martin Rocio , Knol Jan , Oishi Kenji 
Published: July 2016

ABSTRACT

Asymptomatic infant carriers of toxigenic
Clostridium difficile
are suggested to play a role in the transmission of
C. difficile
infection (CDI) in adults. However, the mode of
C. difficile
carriage in infants remains to be fully elucidated. We investigated longitudinal changes in carriage rates, counts, and strain types of toxigenic
C. difficile
in infants. Stools collected from 111 healthy infants in Belgium periodically from birth until the age of 6 months were examined by quantitative PCR targeting 16S rRNA and toxin genes. Toxigenic
C. difficile
was detected in 18 of 111 infants (16%) in the period up to the age of 6 months. The carriage rate of toxigenic
C. difficile
remained below 5% until the age of 3 months. The carriage rate increased to 13% 1 week after weaning (average age, 143 days) and reached 16% at the age of 6 months. Counts of toxigenic
C. difficile
bacteria ranged from 10
4
to 10
8
cells/g of stool. Notably, two infants retained >10
8
cells/g of stool for at least several weeks. Average counts in the 18 infants hovered around 10
7
cells/g of stool from the age of 3 days until the age of 6 months, showing no age-related trend. Genotyping of toxigenic
C. difficile
isolates from the 18 infants revealed that 11 infants each retained a particular monophyletic strain for at least a month. The genotype most frequently identified was the same as that frequently identified in symptomatic adult CDI patients. Thus, toxigenic
C. difficile
strains—potential causes of CDI in adults—colonized the infants' intestines.

IMPORTANCE
Our study provides longitudinal data on counts and strain types of toxigenic
C. difficile
in infants. We found that considerable numbers of toxigenic
C. difficile
bacteria colonized the infants' intestines. The results of strain typing suggest that toxigenic
C. difficile
carried by healthy infants could be potentially pathogenic to adults. These results and findings are informative not only for ecological studies but also for efforts to prevent or control the spread of CDI in adults.
Consumption of a Bifidobacterium bifidum Strain for 4 Weeks Modulates Dominant Intestinal Bacterial Taxa and Fecal Butyrate in Healthy Adults
Authors: Gargari Giorgio , Taverniti Valentina , Balzaretti Silvia , Ferrario Chiara , Gardana Claudio , Simonetti Paolo , Guglielmetti Simone 
Published: July 2016

ABSTRACT

Modulation of the intestinal microbial ecosystem (IME) is a useful target to establish probiotic efficacy in a healthy population. We conducted a randomized, double-blind, crossover, and placebo-controlled intervention study to determine the impact of
Bifidobacterium bifidum
strain Bb on the IME of adult healthy volunteers of both sexes. High-throughput 16S rRNA gene sequencing was used to characterize the fecal microbiota before and after 4 weeks of daily probiotic cell consumption. The intake of approximately one billion live
B. bifidum
cells affected the relative abundance of dominant taxa in the fecal microbiota and modulated fecal butyrate levels. Specifically,
Prevotellaceae
(
P
= 0.041) and
Prevotella
(
P
= 0.034) were significantly decreased, whereas
Ruminococcaceae
(
P
= 0.039) and
Rikenellaceae
(
P
= 0.010) were significantly increased. We also observed that the probiotic intervention modulated the fecal concentrations of butyrate in a manner dependent on the initial levels of short-chain fatty acids (SCFAs). In conclusion, our study demonstrates that a single daily administration of
Bifidobacterium bifidum
strain Bb can significantly modify the IME in healthy (not diseased) adults. These findings demonstrate the need to reassess the notion that probiotics do not influence the complex and stable IME of a healthy individual.

IMPORTANCE
Foods and supplements claimed to contain health-promoting probiotic microorganisms are everywhere these days and mainly intended for consumption by healthy people. However, it is still debated what actual effects probiotic products may have on the healthy population. In this study, we report the results of an intervention trial aimed at assessing the modifications induced in the intestinal microbial ecosystem of healthy adults from the consumption of a probiotic product. Our results demonstrate that the introduction of a probiotic product in the dietary habits of healthy people may significantly modify dominant taxa of the intestinal microbiota, resulting in the modulation of short-chain fatty acid concentrations in the gut. The overall changes witnessed in the probiotic intervention indicate a mechanism of microbiota modulation that could have potential effects on human health.
The Riemerella anatipestifer
AS87_01735
Gene Encodes Nicotinamidase PncA, an Important Virulence Factor
Authors: Wang Xiaolan , Liu Beibei , Dou Yafeng , Fan Hongjie , Wang Shaohui , Li Tao , Ding Chan , Yu Shengqing 
Published: July 2016

ABSTRACT

Riemerella anatipestifer
is a major bacterial pathogen that causes septicemic and exudative diseases in domestic ducks. In our previous study, we found that deletion of the
AS87_01735
gene significantly decreased the bacterial virulence of
R. anatipestifer
strain Yb2 (mutant RA625). The
AS87_01735
gene was predicted to encode a nicotinamidase (PncA), a key enzyme that catalyzes the conversion of nicotinamide to nicotinic acid, which is an important reaction in the NAD
+
salvage pathway. In this study, the
AS87_01735
gene was expressed and identified as the PncA-encoding gene, using an enzymatic assay. Western blot analysis demonstrated that
R. anatipestifer
PncA was localized to the cytoplasm. The mutant strain RA625 (named Yb2Δ
pncA
in this study) showed a similar growth rate but decreased NAD
+
quantities in both the exponential and stationary phases in tryptic soy broth culture, compared with the wild-type strain Yb2. In addition, Yb2Δ
pncA
-infected ducks showed much lower bacterial loads in their blood, and no visible histological changes were observed in the heart, liver, and spleen. Furthermore, Yb2Δ
pncA
immunization of ducks conferred effective protection against challenge with the virulent wild-type strain Yb2. Our results suggest that the
R. anatipestifer
AS87_01735
gene encodes PncA, which is an important virulence factor, and that the Yb2Δ
pncA
mutant can be used as a novel live vaccine candidate.

IMPORTANCE
Riemerella anatipestifer
is reported worldwide as a cause of septicemic and exudative diseases of domestic ducks. The
pncA
gene encodes a nicotinamidase (PncA), a key enzyme that catalyzes the conversion of nicotinamide to nicotinic acid, which is an important reaction in the NAD
+
salvage pathway. In this study, we identified and characterized the
pncA
-homologous gene
AS87_01735
in
R. anatipestifer
strain Yb2.
R. anatipestifer
PncA is a cytoplasmic protein that possesses similar PncA activity, compared with other organisms. Generation of the
pncA
mutant Yb2Δ
pncA
led to a decrease in the NAD
+
content, which was associated with decreased capacity for invasion and attenuated virulence in ducks. Furthermore, Yb2Δ
pncA
immunization of ducks conferred effective protection against challenge with the virulent wild-type strain Yb2. Altogether, these results suggest that PncA contributes to the virulence of
R. anatipestifer
and that the Yb2Δ
pncA
mutant can be used as a novel live vaccine candidate.
Silicate weathering and North Atlantic silica burial during the Paleocene-Eocene Thermal Maximum
Authors: Penman Donald E. 
Published: July 2016

Abstract
During the Paleocene-Eocene Thermal Maximum (PETM, ca. 56 Ma), thousands of gigatons of carbon were released into the ocean and atmosphere over several thousand years, offering the opportunity to study the response of ocean biogeochemistry to a carbon cycle perturbation of a similar magnitude to projected anthropogenic CO2 release. PETM scenarios typically invoke accelerated chemical weathering of terrestrial silicate rocks as a significant negative feedback driving the recovery and termination of the event. However, the implications of this mechanism for the geochemical cycling of silica during the PETM have received little attention. I use “back-of-the-envelope” calculations and a simple two-box geochemical model of the marine silica cycle to demonstrate that the sequestration of thousands of gigatons of carbon by enhanced silicate weathering during the PETM would have dramatically increased the riverine supply of dissolved silica (H4SiO4) to the oceans. This would have elevated seawater [H4SiO4], encouraging both increased opal (SiO2) production by siliceous organisms and enhanced preservation of SiO2 in the water column and sediments. Both of these factors would have promoted a prompt (due to the relatively short oceanic residence time of silica) increase in sedimentary opal burial, thus balancing the marine silica budget. Several recently recovered deep-sea sedimentary records from the central North Atlantic demonstrate elevated SiO2 content across the Paleocene-Eocene boundary, which I argue is the result of enhanced production and/or preservation of SiO2 in response to elevated [H4SiO4] in the North Atlantic, representing the ultimate fate of excess Si weathered from the continents during the PETM.
A matter of minutes: Breccia dike paleomagnetism provides evidence for rapid crater modification
Authors: Fairchild Luke M. , Swanson-Hysell Nicholas L. , Tikoo Sonia M. 
Published: July 2016

Abstract
During an impact event, a crater’s transient structure adjusts gravitationally. Within medium-sized complex craters, a central uplift rises and collapses resulting in large-scale rotations of the target rock. Estimated crater modification rates from numerical models indicate that complex impact craters modify to a structurally stable state within tens of seconds to several minutes after excavation. However, there is little direct geologic evidence constraining these rates. We show how paleomagnetic measurements of lithic breccia dikes emplaced during crater excavation can be used to constrain the rate of crater modification within the central uplift of the ∼34-km-diameter Slate Islands impact structure, Ontario, Canada. The uniformity and linearity of paleomagnetic directions among the clasts and matrix of breccia dikes throughout the impact structure indicate that breccia dikes were frictionally heated above the magnetite Curie temperature (580 °C) during their emplacement and subsequently cooled in situ through magnetic blocking temperatures. The tight grouping of these paleomagnetic directions implies that these breccia dikes cooled and locked in magnetic remanence over a time interval in which the impact structure was not experiencing structural rotations and had already reached a stable state. Conductive cooling of the thinnest sampled breccia dike would have led to the recording of magnetic remanence approximately six minutes after emplacement. This constraint necessitates a stable crater structure only minutes after impact and presents a rare case in which a geological process can be resolved on such a short time scale.
Fault zone characteristics and basin complexity in the southern Salton Trough, California
Authors: Persaud Patricia , Ma Yiran , Stock Joann M. , Hole John A. , Fuis Gary S. , Han Liang 
Published: July 2016

Abstract
Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.
Evidence for a reducing Archean ambient mantle and its effects on the carbon cycle
Authors: Aulbach Sonja , Stagno Vincenzo 
Published: July 2016

Abstract
Chemical reduction-oxidation mechanisms within mantle rocks link to the terrestrial carbon cycle by influencing the depth at which magmas can form, their composition, and ultimately the chemistry of gases released into the atmosphere. The oxidation state of the uppermost mantle has been widely accepted to be unchanged over the past 3800 m.y., based on the abundance of redox-sensitive elements in greenstone belt–associated samples of different ages. However, the redox signal in those rocks may have been obscured by their complex origins and emplacement on continental margins. In contrast, the source and processes occurring during decompression melting at spreading ridges are relatively well constrained. We retrieve primary redox conditions from metamorphosed mid-oceanic ridge basalts (MORBs) and picrites of various ages (ca. 3000–550 Ma), using V/Sc as a broad redox proxy. Average V/Sc values for Proterozoic suites (7.0 ± 1.4, 2σ, n = 6) are similar to those of modern MORB (6.8 ± 1.6), whereas Archean suites have lower V/Sc (5.2 ± 0.4, n = 5). The lower Archean V/Sc is interpreted to reflect both deeper melt extraction from the uppermost mantle, which becomes more reduced with depth, and an intrinsically lower redox state. The pressure-corrected oxygen fugacity (expressed relative to the fayalite-magnetite-quartz buffer, ΔFMQ, at 1 GPa) of Archean sample suites (ΔFMQ –1.19 ± 0.33, 2σ) is significantly lower than that of post-Archean sample suites, including MORB (ΔFMQ –0.26 ± 0.44). Our results imply that the reducing Archean atmosphere was in equilibrium with Earth’s mantle, and further suggest that magmatic gases crossed the threshold that allowed a build-up in atmospheric O2 levels ca. 3000 Ma, accompanied by the first “whiffs” of oxygen in sediments of that age.
Three-dimensional textural and quantitative analyses of orogenic gold at the nanoscale
Authors: Sayab M. , Suuronen J.-P. , Molnár F. , Villanova J. , Kallonen A. , O’Brien H. , Lahtinen R. , Lehtonen M. 
Published: July 2016

Abstract
Ore textures provide direct clues for tracking ore-forming processes. In this regard, most of our knowledge is generally based on two-dimensional (2-D) image analyses, leaving a considerable gap in comprehending three-dimensional (3-D) in-situ textural settings. Recent advances in lab-based and synchrotron radiation–based X-ray computed microtomography and nanotomography have made it possible to visualize and quantify rock volumes in a 3-D space. In this study, we first analyzed microscale textures in oriented drill cores from the world-class Suurikuusikko orogenic gold deposit of northern Finland using lab-based X-ray computed microtomography. The technique revealed a kinematic history and a number of in-situ 3-D quantitative aspects including size, shape, spatial distribution, and geometrical orientation of arsenopyrite and pyrite in a highly altered host-rock matrix. For 3-D nanotomography, the experimental procedure known as holotomography was adopted. Individual arsenopyrite crystals were separated and scanned with voxel sizes ranging from 50 nm to 150 nm using the X-ray nanoprobe beamline (ID16B) at the European Synchrotron Radiation Facility, France. This ultrahigh-resolution technique illustrated the 3-D distribution of micron- to nanoscale gold inclusions, mostly associated with primary rutile or along secondary microfractures inside arsenopyrite. The workflow, from micro- to nanotomography, outlined in this study offers an indispensable new technique in quantifying and characterizing 3-D textural settings of ores, which is otherwise impossible with conventional 2-D imaging devices. The method can also be highly useful in evaluating the amenability of ores to treatment with different processing options.
Meroblastic cleavage identifies some Ediacaran Doushantuo (China) embryo-like fossils as metazoans
Authors: Yin Zongjun , Zhu Maoyan , Bottjer David J. , Zhao Fangchen , Tafforeau Paul 
Published: July 2016

Abstract
Ediacaran Doushantuo (Formation) embryo-like fossils (EDEFs, ca. 600 Ma) from South China display cellular and sub-cellular structures and provide a unique window on the early evolution of multicellular eukaryotes. But there have been widely disparate interpretations of these fossils. Here we report new fossil embryo-like forms from the Doushantuo phosphorite that exhibit a meroblastic cleavage pattern. Our results from high-resolution propagation phase contrast–synchrotron radiation X-ray microtomography (PPC-SRµCT) demonstrate that these fossils preserve features directly comparable to those of modern meroblastic animal embryos that utilize discoidal cleavage. Given that discoidal-type meroblastic cleavage occurs only in metazoans, the phylogenetic positions of these fossils probably fall into the animal branch of the holozoan tree. Meroblastic as well as holoblastic cleavage forms were thus present by ca. 600 Ma, substantiating the conclusion derived from molecular clock estimates that a variety of metazoan lineages had evolved by the mid-Ediacaran after the termination of the Marinoan glaciation, if not earlier.
Selecting children for head CT following head injury
Authors: Kemp A , Nickerson E , Trefan L , Houston R , Hyde P , Pearson G , Edwards R , Parslow RC , Maconochie I 
Published: July 2016

ObjectiveIndicators for head CT scan defined by the 2007 National Institute for Health and Care Excellence (NICE) guidelines were analysed to identify CT uptake, influential variables and yield.DesignCross-sectional study.SettingHospital inpatient units: England, Wales, Northern Ireland and the Channel Islands.PatientsChildren (<15 years) admitted to hospital for more than 4 h following a head injury (September 2009 to February 2010).InterventionsCT scan.Main outcome measuresNumber of children who had CT, extent to which NICE guidelines were followed and diagnostic yield.ResultsData on 5700 children were returned by 90% of eligible hospitals, 84% of whom were admitted to a general hospital. CT scans were performed on 30.4% of children (1734), with a higher diagnostic yield in infants (56.5% (144/255)) than children aged 1 to 14 years (26.5% (391/1476)). Overall, only 40.4% (984 of 2437 children) fulfilling at least one of the four NICE criteria for CT actually underwent one. These children were much less likely to receive CT if admitted to a general hospital than to a specialist centre (OR 0.52 (95% CI 0.45 to 0.59)); there was considerable variation between healthcare regions. When indicated, children >3 years were much more likely to have CT than those <3 years (OR 2.35 (95% CI 2.08 to 2.65)).ConclusionCompliance with guidelines and diagnostic yield was variable across age groups, the type of hospital and region where children were admitted. With this pattern of clinical practice the risks of both missing intracranial injury and overuse of CT are considerable.
Accumulated workloads and the acute:chronic workload ratio relate to injury risk in elite youth football players
Authors: Bowen Laura , Gross Aleksander Stefan , Gimpel Mo , Li François-Xavier 
Published: July 2016

AimThe purpose of this study was to investigate the relationship between physical workload and injury risk in elite youth football players.MethodsThe workload data and injury incidence of 32 players were monitored throughout 2 seasons. Multiple regression was used to compare cumulative (1, 2, 3 and 4-weekly) loads and acute:chronic (A:C) workload ratios (acute workload divided by chronic workload) between injured and non-injured players for specific GPS and accelerometer-derived variables:total distance (TD), high-speed distance (HSD), accelerations (ACC) and total load. Workloads were classified into discrete ranges by z-scores and the relative risk was determined.ResultsA very high number of ACC (≥9254) over 3 weeks was associated with the highest significant overall (relative risk (RR)=3.84) and non-contact injury risk (RR=5.11). Non-contact injury risk was significantly increased when a high acute HSD was combined with low chronic HSD (RR=2.55), but not with high chronic HSD (RR=0.47). Contact injury risk was greatest when A:C TD and ACC ratios were very high (1.76 and 1.77, respectively) (RR=4.98).ConclusionsIn general, higher accumulated and acute workloads were associated with a greater injury risk. However, progressive increases in chronic workload may develop the players' physical tolerance to higher acute loads and resilience to injury risk.
Prevalence of overweight and obesity and some associated factors among adult residents of northeast China: a cross-sectional study
Authors: Wang Rui , Zhang Peng , Gao Chunshi , Li Zhijun , Lv Xin , Song Yuanyuan , Yu Yaqin , Li Bo 
Published: July 2016

ObjectivesThis study aims to estimate the prevalence of overweight and obesity and determine potential influencing factors among adults in northeast China.MethodsA cross-sectional survey was conducted in Jilin Province, northeast China, in 2012. A total of 9873 men and 10 966 women aged 18–79 years from the general population were included using a multistage stratified random cluster sampling design. Data were obtained from face-to-face interview and physical examination. After being weighted according to a complex sampling scheme, the sample was used to estimate the prevalence of overweight (body mass index (BMI) 24–27.9 kg/m2) and obesity (BMI >28 kg/m2) in Jilin Province, and analyse influencing factors through corresponding statistical methods based on complex sampling design behaviours.ResultsThe overall prevalence of overweight was 32.3% (male 34.3%; female 30.2%), and the prevalence of obesity was 14.6% (male 16.3%; female 12.8%) in Jilin Province. The prevalence of both overweight and obesity were higher in men than women (p<0.001). Influencing factors included sex, age, marriage status, occupation, smoking, drinking, diet and hours of sleep (p<0.05).ConclusionsThis study estimated that the prevalence of overweight and obesity among adult residents of Jilin Province, northeast China, were high. The results of this study will be submitted to the Health Department of Jilin Province and other relevant departments as a reference, which should inform policy makers in developing education and publicity to prevent and control the occurrence of overweight and obesity.