It has so far remained a major challenge to quantitatively predict the boson peak, a THz vibrational anomaly universal for glasses, from features in the amorphous structure. Using molecular dynamics ...simulations of a model Cu_{50}Zr_{50} glass, we decompose the boson peak to contributions from atoms residing in different types of Voronoi polyhedra. We then introduce a microscopic structural parameter to depict the "orientational order," using the vector pointing from the center atom to the farthest vertex of its Voronoi coordination polyhedron. This order parameter represents the most probable direction of transverse vibration at low frequencies. Its magnitude scales linearly with the boson peak intensity, and its spatial distribution accounts for the quasilocalized modes. This correlation is shown to be universal for different types of glasses.
Background
Oral fluconazole is used to treat vulvovaginal candidiasis during pregnancy. However, there are concerns regarding the pregnancy outcomes following exposure to fluconazole.
Objectives
To ...evaluate the pregnancy outcomes associated with exposure to oral fluconazole during the first trimester of pregnancy.
Search strategy
A systematic literature search was conducted to identify relevant studies published from inception until April 2019.
Selection criteria
Relevant English‐language citations using the terms oral fluconazole and pregnancy in humans.
Data collection
Two reviewers independently ed data and assessed study quality.
Main results
Oral fluconazole use during the first trimester of pregnancy was marginally associated with an increased risk of congenital malformations (odds ratio OR 1.09, 95% CI 0.99–1.2, P = 0.088; n = 6 studies), whereas in the subgroup analysis, this association existed only for high‐dose users (>150 mg) (OR 1. 19, 95% CI 1.01–1.4, P = 0.039; n = 2). Exposure to fluconazole also increased the risk of heart malformations (OR 1.31, 95% CI 1.09–1.57, P = 0.003; n = 4), cardiac septal defects (OR 1.3, 95% CI 1.1–1.67, P = 0.047; n = 3), and tetralogy of Fallot (OR 3.39 95% CI 1.71–6.74, P < 0.001; n = 2) in the offspring. In addition, exposure to fluconazole was significantly associated with an increased risk of spontaneous abortion (OR 1.99, 95% CI 1.38–2.88, P < 0.001; n = 3).
Conclusions
Oral fluconazole use during the first trimester of pregnancy appears to be associated with heart malformations and spontaneous abortion, but a causal link cannot be proven.
Tweetable
Oral fluconazole during the first trimester of pregnancy may be associated with unfavourable pregnancy outcomes.
Tweetable
Oral fluconazole during the first trimester of pregnancy may be associated with unfavourable pregnancy outcomes.
To explore the characteristics of Helicobacter pylori resistance in China and the association between antibiotic resistance and several clinical factors.
H. pylori strains were collected from ...patients in 13 provinces or cities in China between 2010 and 2016. Demographic data including type of disease, geographic area, age, gender and isolation year were collected to analyse their association with antibiotic resistance. Antibiotic resistance was detected using the Etest test and the Kirby-Bauer disc diffusion method.
H. pylori were successfully cultured from 1117 patients. The prevalence of metronidazole, clarithromycin (CLA), azithromycin, levofloxacin (LEV), moxifloxacin, amoxicillin (AMO), tetracycline and rifampicin resistance was 78.2, 22.1, 23.3, 19.2, 17.2, 3.4, 1.9 and 1.5%, respectively. No resistance to furazolidone was observed. The resistance rates to LEV and moxifloxacin were higher in strains isolated from patients with gastritis compared to those with duodenal ulcer and among women. Compared to patients ≥40 years old, younger patients exhibited lower resistance rates to CLA, azithromycin, LEV and moxifloxacin. The resistance rates to CLA and AMO were higher in strains isolated more recently, and we also found that the prevalence of resistance to metronidazole, CLA, azithromycin and AMO were significantly different among different regions of China.
The resistance rates to metronidazole, CLA and LEV were high in China. Patient age, gender, disease and location were associated with the resistance of H. pylori to some antibiotics. Furazolidone, AMO and tetracycline are better choices for H. pylori treatment in China.
...variables associated with RBC transfusion should be included in IPW, such as disease severity, hemoglobin level necessitating transfusion, reasons for hypo-hemoglobinemia, etc. ...there is a risk ...that the propensity score model for the exposure variable may be biased. According to current transfusion guidelines, RBC transfusions were commonly initiated at a low RBC threshold (7–8 g/dL) 5. ...as a strong transfusion indication and a significant risk for mortality, the lowest hemoglobin level should be balanced in the propensity score model or adjusted in the Cox-regression model (if not, there is a risk that the association between RBC transfusion and mortality may be mediated by the lowest hemoglobin level: lowest hemoglobin leads to RBC transfusion, and lowest hemoglobin leads to high mortality, which generated the relationship between RBC transfusion and mortality). ...in the current study, only hemoglobin at inclusion was included in the Cox-regression model. ...although the AIPW approach was adopted, there is still a relatively high risk of bias due to inadequate confounder selection.
HfO2-based ferroelectric film has shown great potential for the application of ferroelectric memory due to its great advantages as compared to traditional ferroelectrics. However, the origin of the ...ferroelectricity of the HfO2-based ferroelectric film is still under debate. In this work, by performing ab initial molecular dynamics calculation, the phase stability and the polarization switching behavior of HfO2 were systematically studied to illuminate the intrinsic origin its ferroelectricity. Results show that, under different in-plane constraints and room temperature, the out-of-plane polarized orthorhombic ferroelectric phase Pca21 is always the metastable phase of HfO2. As driven by the out-of-plane electric field, HfO2 exhibits linear dielectric behavior or antiferroelectric behavior with the ferroelectric–tetragonal–ferroelectric phase transformation under in-plane compression. With the tensile strain condition, the nonferroelectric HfO2 could be transformed to be the out-of-plane polarized orthorhombic ferroelectric phase, which shows good ferroelectricity under a periodic electric field. The triggered phase transformation and ferroelectricity as modulated by the epitaxial constraint as found in this work were verified by a recent experiment and should be the intrinsic origin of the ferroelectricity of HfO2-based films.
Objective
To systematically assess the prevalence of frailty, including prefrailty, stratified prevalence according to frailty criteria, gender, age, and region, and the risk factors for frailty in ...China.
Design
We conducted a systematic literature review and meta-analysis using articles available in 8 databases including PubMed, Cochrane Library, Web of Science, CINAHL Plus, China Knowledge Resource Integrated Database (CNKI), Wanfang Database, Chinese Biomedical Database (CBM), and Weipu Database (VIP).
Setting
Crosssectional and cohort data from Chinese community.
Participants
Community-dwelling adults aged 65 and older.
Measurements
Two authors independently extracted data based upon predefined criteria. Where data were available we conducted a meta-analysis of frailty parameters using a random-effects model.
Results
We screened 915 different articles, and 14 studies (81258 participants) were ultimately included in this analysis. The prevalence of frailty and prefrailty in individual studies varied from 5.9% to 17.4% and from 26.8% to 62.8%, respectively. The pooled prevalence of frailty and prefrailty were 10% (95% CI: 8% to 12%, I2 = 97.4%, P = 0.000) and 43% (95% CI: 37% to 50%, I2 = 98.0%, P = 0.000), respectively. The pooled frailty prevalence was 8% for the Fried frailty phenotype, 12% for the frail index, and 15% for the FRAIL scale. Age-stratified meta-analyses showed the pooled prevalence of frailty to be 6%, 15%, and 25% for those aged 65–74, 75–84, and ≥85 years old, respectively. The pooled prevalence of frailty was 8% for males and 11% for females. The pooled prevalence of frailty in Mainland China, Taiwan, and Hong Kong was 12%, 8%, and 14%, respectively. The pooled frailty prevalence was 10% in urban areas and 7% in rural areas. After controlling for confounding variables, increasing age (OR = 1.28, 95% CI: 1.2 to 1.36, I
2
= 98.0%, P = 0.000), being female (OR = 1.29, 95% CI: 1.16 to 1.43, I
2
=92.7%, P=0.000), activities of daily living (ADL) disability (OR = 1.72, 95% CI: 1.57 to 1.90, I
2
= 99.7%, P = 0.000), and having three or more chronic diseases (OR = 1.97, 95% CI: 1.78 to 2.18, I
2
= 97.5%, P = 0.000) were associated with frailty.
Conclusions
These findings of this review indicate an overall pooled prevalence of frailty among Chinese community-dwelling older people of 10%. Increasing age, being female, ADL disability, and having three or more chronic diseases were all risk factors for frailty. Further research will be needed to identify additional frailty risk factors in order to better treat and prevent frailty in the community.
Summary Objective The major complaint of Osteoarthritis (OA) patients is pain. However, due to the nature of clinical studies and the limitation of animal studies, few studies have linked function ...impairment and behavioral changes in OA animal models to cartilage loss and histopathology. Our objective was to study surrogate markers of functional impairment in relation to cartilage loss and pathological changes in a post-traumatic mouse model of OA. Method We performed a battery of functional analyses in a mouse model of OA generated by cruciate ligament transection (CLT). The changes in functional analyses were linked to histological changes graded by OARSI standards, histological grading of synovitis, and volumetric changes of the articular cartilage and osteophytes quantified by phase contrast micro-computed tomography (μCT). Results OA generated by CLT led to decreased time on rotarod, delayed response on hotplate analysis, and altered gait starting from 4 weeks after surgery. Activity in open field analysis did not change at 4, 8, or 12 weeks after CLT. The magnitude of behavioral changes was directly correlated with higher OARSI histological scores of OA, synovitis in the knee joints, cartilage volume loss, and osteophyte formation. Conclusion Our findings link functional analyses to histological grading, synovitis, comprehensive three-dimensional assessment of cartilage volume and osteophyte formation. This serves as a reference for a mouse model in predicting outcomes of OA treatment.
Multi-directional impact forging (MDIF) with high strain rate shows high grain refinement efficiency and texture randomization effect in magnesium alloys. AZ61 Mg alloy was subjected to MDIF process, ...and the related grain refinement mechanisms and texture development were investigated. MDIF resulted in a homogeneous microstructure with fine grains of 11 μm and non-basal texture, which was ascribed to the consecutive twinning and dynamic recrystallization (DRX). During the early forging passes, twin-induced DRX associated with {10–11} contraction and {10–11}-{10–12} double twins, and the coalescence and intersection of {10–12} extension twins with various variants effectively refined the coarse original grains and randomized the texture. With continuous forging, continuous and discontinuous DRX subsequently took place and eventually led to the fully DRXed microstructure and double-peak texture. Besides, fine spherical β-Mg17Al12 particles were dynamically precipitated along the original grain boundaries, acting as the preferred nucleation sites for DRX by particle-stimulated nucleation mechanism (PSN). Meanwhile, these particles became effective pinning obstacles for suppressing the DRXed grain growth.
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•MDIF resulted in a homogenous microstructure with fine grains of 11 μm.•Highly efficient grain refinement was ascribed to consecutive twinning and DRX.•Twinning and DRX dominate texture development during MDIF.•Dynamic precipitates along original GBs were preferred nucleation for DRX by PSN.
Three dilute Mg-Zn-Ca-Mn alloys were successfully extruded at 24m/min and the alloy with lowest Zn content (0.21wt%) can even be extruded at 60m/min without any surface defects, which was ascribed to ...the thermally stable Mg2Ca phase and high solidus temperature (∼620°C). The alloys extruded at die-exit speed ≥6m/min showed a fully dynamically recrystallized (DRXed) microstructure and weak rare earth (RE) texture at the position between 21̅1̅4 and 21̅1̅2 parallel to the extrusion direction. Besides, fine Mg2Ca and α-Mn particles dynamically precipitated during extrusion, acting as effective pinning obstacles against the DRXed grain growth via Zener drag effect. Due to the deformation temperature rise with increasing extrusion speeds, the grain size increased gradually, which can be understood from the relationship between DRXed grain size and Zener-Hollomon parameter. The RE texture contributed to high uniform elongation of ∼23%, but the increased grain size (>30µm) deteriorated post-uniform elongation due to the prevalence of {101̅1} contraction and {101̅1}-{101̅2} double twins during post-uniform deformation.
Rare earth (RE) lanthanum chloride was used to modify carbon nanotubes (CNTs) to obtain rare earth modified carbon nanotubes (RECNTs). The modified CNTs were characterized by Fourier transform ...infrared spectroscopy and X-ray photoelectron spectroscopy. The results show that RE has a significant effect on improving the surface activity of carbon nanotubes. Through the chemical function of RE, the CNTs were successfully grafted with functional groups such as amino groups and carboxyl groups. This method can be used to connect any oxygen- or nitrogen-containing functional groups to the CNTs according to actual needs. Then, the modified CNTs were incorporated into epoxy resin (EP) to prepare composite (REACNTs/EP). The mechanical properties of the composites were tested by Zwick/Roell Z100 and Zwick/Roell Z20 test machine, and the tensile fractural sections were analyzed by scanning electron microscopy, and compared to the composites prepared with untreated CNTs (CNTs/EP), acidified carbon nanotubes (ACNTs/EP), acidification and RE synergistic modification of carbon nanotubes (REACNTs/EP). The results show that the ultimate tensile strength and tensile modulus of RECNTs/EP were increased by 33.9%, 73.7%, respectively, compared with pure EP, while the properties of REACNTs/EP were increased by 50.7%, 90.9%, indicating that RE has excellent effect on improving the mechanical properties of carbon nanotube-reinforced composites.
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