968 research outputs found
Risk factors associated with preterm birth among singletons following assisted reproductive technology in Australia 2007-2009-a population-based retrospective study
© Xu et al. Background: Preterm birth, a leading cause of neonatal death, is more common in multiple births and thus there has being an increasing call for reducing multiple births in ART. However, few studies have compared risk factors for preterm births amongst ART and non-ART singleton birth mothers. Methods: A population-based study of 393,450 mothers, including 12,105 (3.1%) ART mothers, with singleton gestations born between 2007 and 2009 in 5 of the 8 jurisdictions in Australia. Univariable and multivariable logistic regression models were conducted to evaluate socio-demographic, medical and pregnancy factors associated with preterm births in contrasting ART and non-ART mothers. Results: Ten percent of singleton births to ART mothers were preterm compared to 6.8% for non-ART mothers (P 34), socioeconomic disadvantage (most disadvantaged quintile Odds Ratio (OR) 0.95, 95% Confidence Interval (CI): 0.77-1.17), smoking (OR 1.12, 95%CI: 0.79-1.61) and priminarity (OR 1.19, 95% CI: 1.05-1.35, AOR not significant) shown to be associated with elevated risk of preterm birth for non-ART mothers were not demonstrated for ART mothers, even after adjusting for potential confounders. Nonetheless, in multivariable analysis, the association between ART and the elevated risk for singleton preterm birth persisted after controlling for all included confounding medical, pregnancy and socio-economic factors (AOR 1.51, 95% CI: 1.42-1.61). Conclusions: Preterm birth rate is approximately one-and-a-half-fold higher in ART mothers than non-ART mothers albeit for singleton births after controlling for confounding factors. However, ART mothers were less subject to the adverse influence from socio-demographic factors than non-ART mothers. This has implications for counselling prospective parents
Strain Softening Induced by High Pressure Torsion in Copper Alloys
Three kinds of Cu-Al alloys and a pure Cu sample with different stacking fault energies (SFEs) are deformed using room temperature rolling (RR) and high pressure torsion (HPT), respectively. The microstructure is analysed by means of transaction electron microscopy and X-ray diffraction. It is found that HIPT is more feasible to obtain nanocrystals and profuse twins. Tailoring the SFE can promote sample strength without sacrificing the ductility of the Cu alloys. The tensile properties of samples processed by HPT and RR are compared. It is discovered that the HPT process leads to the strain softening phenomenon in samples with relatively high SFE. The excellent mechanical properties can be obtained in samples deformed by HPT with a SFE of 6 mJ/m(2), in which strain softening was restrained and strain hardening played a dominant role in the deformation process. The relationship between tensile properties and microstructures of the deformed metals is also investigated.110Ysciescopu
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Assessing the Impact of Germination and Sporulation Conditions on the Adhesion of Bacillus Spores to Glass and Stainless Steel by Fluid Dynamic Gauging
The adhesion of spores of three Bacillus species with distinctive morphologies to stainless steel and borosilicate glass was studied using the fluid dynamic gauging technique. Marked differences were observed between different species of spores, and also between spores of the same species prepared under different sporulation conditions. Spores of the food borne pathogen B. cereus were demonstrated to be capable of withstanding shear stresses greater than 1500 Pa when adhered to stainless steel, in contrast to spores of B. subtilis and B. megaterium, which detached in response to lower shear stress. An extended DLVO model was shown to be capable of predicting the relative differences in spore adhesion between spores of different species and different culture conditions, but did not predict absolute values of force of adhesion well. Applying the model to germinating spores showed a significant reduction in adhesion force shortly after triggering germination, indicating a potential strategy to achieve enhanced removal of spores from surfaces in response to shear stress, such as during cleaning-in-place procedures.An EPSRC DTG studentship for KXZ and the expertise of A. Hubbard in constructing and maintaining the apparatus are gratefully acknowledged. Dr Florencia Wisnivesky assisted in the SEM imaging
Evidence for genetic association of TBX21 and IFNG with systemic lupus erythematosus in a Chinese Han population
TBX21 recode T-bet which is an important transcription factor that drives the Th1 immune response primarily by promoting expression of the interferon-gamma (IFNG) gene. Recent studies have shown that genetic variants in TBX21 and IFNG are connected with risk of systemic lupus erythematosus (SLE). The aim of the present study was to replicate these genetic associations with SLE in Anhui Chinese population. Genotyping of 3 variants (rs4794067 in TBX21, rs2069705 and rs2069718 in IFNG) was performed. A total of 3732 subjects were included in the final analysis. The study only identified the association of rs2069705 with SLE susceptibility (T vs. C: odds ratio [OR] = 1.12, 95% confidence interval [CI] = 1.00-1.26, P = 0.046). Combined analysis with Hong Kong GWAS showed that the OR for rs2069705 was 1.10 (95% CI: 1.01-1.21, P = 0.027). Further pooled analysis with Korean populations involving 10498 subjects showed a more significant association between rs2069705 and SLE (T vs. C: OR = 1.11, 95%CI = 1.04-1.19, P = 0.002; TT + TC vs. CC: OR = 1.11, 95%CI = 1.02-1.21, P = 0.012; TT vs. TC + CC: OR = 1.28, 95%CI = 1.07-1.54, P = 0.008; TT vs. CC: OR = 1.33, 95%CI = 1.10-1.60, P = 0.003). In addition, we also identified a significant genetic interaction between rs2069705 and rs4794067 in Anhui Chinese population. Our study suggests that IFNG and IFNG-TBX21 interaction are involved in SLE susceptibility.published_or_final_versio
Influence of the dimensions of spheroniser plate protuberances on the production of pellets by extrusion-spheronisation
This study systematically investigated the influence of the dimensions of square-patterned pyramidal protuberances on a spheronisation plate on pellet yield, size and shape distributions, surface tensile strength and surface morphology was investigated using a 45 wt% microcrystalline cellulose/ water paste. Tests were conducted using four different extrudate diameters (1.0, 1.5, 2.0 and 2.5 mm) generated by screen extrusion and seven plate geometries, including a flat plate as a control, allowing the relative size of extrudate to protuberance feature to be studied. Geometrical analyses of the protuberance shapes provide some insight into the observed differences, with protuberance angle being significant in many cases. Sharper protuberances reduced yield (promoting breakage and attrition) but tended to give narrower size distributions and more uneven pellet surface. Pellet yield for 1 mm extrudates was also subject to losses caused by fragments passing through the 1.0 mm gap between the plate and spheroniser wall. Pellet tensile strength was noticeably greater for 1.0 mm diameter extrudates, which is attributed to the greater extensional strain imparted on the paste during the extrusion step. For some geometries there is an optimal ratio of extrudate to protuberance dimensions
Optically Tunable Resistive-Switching Memory in Multiferroic Heterostructures
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Imperialibacter roseus gen. nov., sp nov., a novel bacterium of the family Flammeovirgaceae isolated from Permian groundwater
A novel bacterial strain, designated P4(T), was isolated from Permian groundwater and identified on the basis of its phylogenetic, genotypic, chemotaxonomic and phenotypic characteristics. Cells were aerobic, Gram-stain-negative rods. 16S rRNA gene sequence-based phylogenetic analysis revealed that P4(T) is affiliated with the family Flammeovirgaceae in the phylum Bacteroidetes, but forms a distinct cluster within this family. The DNA G+C content of strain P4(T) was 45.2 mol%. The predominant cellular fatty acids were C-16:1 omega 6C/C-16:1 omega 7c and iso-C-15:0. MK-7 was the main respiratory quinone. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, unidentified phospholipids, an unidentified aminolipid, unidentified glycolipids and unidentified polar lipids. Based on our extensive polyphasic analysis, a novel species in a new genus, Imperialibacter roseus gen. nov., sp. nov., is proposed. The type strain of Imperialibacter roseus is P4(T) (=CICC 10659(T)=KCTC 32399(T)).A novel bacterial strain, designated P4(T), was isolated from Permian groundwater and identified on the basis of its phylogenetic, genotypic, chemotaxonomic and phenotypic characteristics. Cells were aerobic, Gram-stain-negative rods. 16S rRNA gene sequence-based phylogenetic analysis revealed that P4(T) is affiliated with the family Flammeovirgaceae in the phylum Bacteroidetes, but forms a distinct cluster within this family. The DNA G+C content of strain P4(T) was 45.2 mol%. The predominant cellular fatty acids were C-16:1 omega 6C/C-16:1 omega 7c and iso-C-15:0. MK-7 was the main respiratory quinone. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, unidentified phospholipids, an unidentified aminolipid, unidentified glycolipids and unidentified polar lipids. Based on our extensive polyphasic analysis, a novel species in a new genus, Imperialibacter roseus gen. nov., sp. nov., is proposed. The type strain of Imperialibacter roseus is P4(T) (=CICC 10659(T)=KCTC 32399(T))
Biological diversification linked to environmental stabilization following the Sturtian Snowball glaciation
The body fossil and biomarker records hint at an increase in biotic complexity between the two Cryogenian Snowball Earth episodes (ca. 661 million to ≤650 million years ago). Oxygen and nutrient availability can promote biotic complexity, but nutrient (particularly phosphorus) and redox dynamics across this interval remain poorly understood. Here, we present high-resolution paleoredox and phosphorus phase association data from multiple globally distributed drill core records through the non-glacial interval. These data are first correlated regionally by litho- and chemostratigraphy, and then calibrated within a series of global chronostratigraphic frameworks. The combined data show that regional differences in postglacial redox stabilization were partly controlled by the intensity of phosphorus recycling from marine sediments. The apparent increase in biotic complexity followed a global transition to more stable and less reducing conditions in shallow to mid-depth marine environments and occurred within a tolerable climatic window during progressive cooling after post-Snowball super-greenhouse conditions
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