Background
Diet and exercise during pregnancy have been used to prevent gestational diabetes mellitus (GDM) with some success.
Objective
To examine the effectiveness of lifestyle intervention on GDM ...prevention and to identify key effectiveness moderators to improve the prevention strategy.
Search strategy
Pubmed, Scopus, Cochrane, and cross‐references were searched.
Selection criteria
Randomised controlled trials (RCTs) evaluating lifestyle interventions during pregnancy for GDM prevention.
Data collection and analysis
Two independent reviewers extracted data. A random‐effects model was used to analyse the relative risk (RR) and 95% confidence interval (95% CI). Meta‐regressions and subgroup analyses were used to investigate important moderators of effectiveness.
Main results
Forty‐seven RCTs involving 15 745 participants showed that diet and exercise during pregnancy were preventive of GDM (RR 0.77, 95% CI 0.69–0.87). Four key aspects were identified to improve the preventive effect: targeting the high‐risk population; an early initiation of the intervention; the correct intensity and frequency of exercise; and gestational weight gain management. Although 24 RCTs targeted women who were overweight or obese, body mass index (BMI) failed to predict the effectiveness of an intervention. Instead, interventions are most effective in high‐incidence populations rather than simply in women who are overweight or obese. Furthermore, exercise of moderate intensity for 50–60 minutes twice a week could lead to an approximately 24% reduction in GDM.
Conclusion
The best strategy to prevent GDM is to target the high‐risk population predicted by risk evaluation models and to control the gestational weight gain of women through intensified diet and exercise modifications early in their pregnancy.
Tweetable
Four key effectiveness moderators of lifestyle interventions for GDM prevention.
Tweetable
Four key effectiveness moderators of lifestyle interventions for GDM prevention.
Dapsone is used in the treatment of infections and inflammatory diseases. The dapsone hypersensitivity syndrome, which is associated with a reported mortality of 9.9%, develops in about 0.5 to 3.6% ...of persons treated with the drug. Currently, no tests are available to predict the risk of the dapsone hypersensitivity syndrome.
We performed a genomewide association study involving 872 participants who had received dapsone as part of multidrug therapy for leprosy (39 participants with the dapsone hypersensitivity syndrome and 833 controls), using log-additive tests of single-nucleotide polymorphisms (SNPs) and imputed HLA molecules. For a replication analysis, we genotyped 24 SNPs in an additional 31 participants with the dapsone hypersensitivity syndrome and 1089 controls and performed next-generation sequencing for HLA-B and HLA-C typing at four-digit resolution in an independent series of 37 participants with the dapsone hypersensitivity syndrome and 201 controls.
Genomewide association analysis showed that SNP rs2844573, located between the HLA-B and MICA loci, was significantly associated with the dapsone hypersensitivity syndrome among patients with leprosy (odds ratio, 6.18; P=3.84×10(-13)). HLA-B*13:01 was confirmed to be a risk factor for the dapsone hypersensitivity syndrome (odds ratio, 20.53; P=6.84×10(-25)). The presence of HLA-B*13:01 had a sensitivity of 85.5% and a specificity of 85.7% as a predictor of the dapsone hypersensitivity syndrome, and its absence was associated with a reduction in risk by a factor of 7 (from 1.4% to 0.2%). HLA-B*13:01 is present in about 2 to 20% of Chinese persons, 1.5% of Japanese persons, 1 to 12% of Indians, and 2 to 4% of Southeast Asians but is largely absent in Europeans and Africans.
HLA-B*13:01 was associated with the development of the dapsone hypersensitivity syndrome among patients with leprosy. (Funded by the National Natural Science Foundation of China and others.).
Nitrous acid (HONO) plays a key role in atmospheric chemistry by influencing the budget of hydroxyl radical (OH). In this study, a two-month measurement of HONO and related quantities were analyzed ...during a biomass burning season in 2012 at a suburban site in the western Yangtze River delta, eastern China. An overall high HONO concentration with the mean value of 0.76 ppbv (0.01 ppbv to 5.95 ppbv) was observed. During biomass burning (BB) periods, both HONO concentration and HONO/NO2 ratio were enhanced significantly (more than a factor of 2, p < 0.01) compared with non-biomass burning (non-BB) periods. A correlation analysis showed that the HONO in BB plumes was more correlated with nitrogen dioxide (NO2) than that with potassium (a tracer of BB). Estimation by the method of potassium tracing suggests a maximum contribution of 17 plus or minus 12% from BB emission to the observed HONO concentrations, and the other over 80% of the observed nighttime HONO concentrations during BB periods were secondarily produced by the heterogeneous conversion of NO2. The NO2-to-HONO conversion rate (CHONO) in BB plumes was almost twice as that in non-BB plumes (0.0062 hr-1 vs. 0.0032 hr-1). Given that the residence time of the BB air masses was lower than that of non-BB air masses, these results suggest BB aerosols have higher NO2 conversion potentials to form HONO than non-BB aerosols. A further analysis based on comparing the surface area at similar particle mass levels and HONO/NO2 ratios at similar surface area levels suggested larger specific surface areas and higher NO2 conversion efficiencies of BB aerosols. A mixed plume of BB and anthropogenic fossil fuel (FF) emissions was observed on 10 June with even higher HONO concentrations and HONO/NO2 ratios. The strong HONO production potential (high HONO/NO2 to PM2.5 ratio) was accompanied with a high sulfate concentration in this plume, suggesting a promotion of mixed aerosols to the HONO formation. In summary, our study suggests an important role of BB in atmospheric chemistry by affecting the HONO budget. This can be especially important in eastern China, where agricultural burning plumes are inevitably mixed with urban and industrial pollution.
Abstract
Topological superconductors (TSCs) are unconventional superconductors with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for ...quantum computation. Despite their importance in both fundamental research and applications, natural TSCs are very rare. Here, combining state of the art synchrotron and laser-based angle-resolved photoemission spectroscopy, we investigated a stoichiometric transition metal dichalcogenide (TMD), 2M-WS
2
with a superconducting transition temperature of 8.8 K (the highest among all TMDs in the natural form up to date) and observed distinctive topological surface states (TSSs). Furthermore, in the superconducting state, we found that the TSSs acquired a nodeless superconducting gap with similar magnitude as that of the bulk states. These discoveries not only evidence 2M-WS
2
as an intrinsic TSC without the need of sensitive composition tuning or sophisticated heterostructures fabrication, but also provide an ideal platform for device applications thanks to its van der Waals layered structure.
Aerosol particles play important roles in regional air quality and global climate change. In this study, we analyzed 2 years (2011–2013) of measurements of submicron particles (6–800 nm) at a ...suburban site in the western Yangtze River Delta (YRD) of eastern China. The number concentrations (NCs) of particles in the nucleation, Aitken and accumulation modes were 5300 ± 5500, 8000 ± 4400, 5800 ± 3200 cm−3, respectively. The NCs of total particles are comparable to those at urban/suburban sites in other Chinese megacities, such as Beijing, but about 10 times higher than in the remote western China. Long-range and regional transport largely influenced number concentrations and size distributions of submicron particles. The highest and lowest accumulation-mode particle number concentrations were observed in air masses from the YRD and coastal regions, respectively. Continental air masses from inland brought the highest concentrations of nucleation-mode particles. New particle formation (NPF) events, apparent in 44 % of the effective measurement days, occurred frequently in all the seasons except winter. The frequency of NPF in spring, summer and autumn is much higher than other measurement sites in China. Sulfuric acid was found to be the main driver of NPF events. The particle formation rate was the highest in spring (3.6 ± 2.4 cm−3 s−1), whereas the particle growth rate had the highest values in summer (12.8 ± 4.4 nm h−1). The formation rate was typically high in relatively clean air masses, whereas the growth rate tended to be high in the polluted YRD air masses. The frequency of NPF events and the particle growth rates showed a strong year-to-year difference. In the summer of 2013, associated with a multi-week heat wave and strong photochemical processes, NPF events occurred with larger frequency and higher growth rates compared with the same period in 2012. The difference in the location and strength of the subtropical high pressure system, which influences the air mass transport pathways and solar radiation, seems to be the cause for year-to-year differences. This study reports, up to now, the longest continuous measurement records of submicron particles in eastern China and helps to achieve a comprehensive understanding of the main factors controlling the seasonal and year-to-year variation of the aerosol size distribution and NPF in this region.
The general relationships between vegetation and water yield under different climatic regimes are well established at a small watershed scale in the past century. However, applications of these basic ...theories to evaluate the regional effects of land cover change on water resources remain challenging due to the complex interactions of vegetation and climatic variability and hydrologic processes at the large scale. The objective of this study was to explore ways to examine the spatial and temporal effects of a large ecological restoration project on water yield across the Loess Plateau region in northern China. We estimated annual water yield as the difference between precipitation input and modelled actual evapotranspiration (ET) output. We constructed a monthly ET model using published ET data derived from eddy flux measurements and watershed streamflow data. We validated the ET models at a watershed and regional levels. The model was then applied to examine regional water yield under land cover change and climatic variability during the implementation of the Grain-for-Green (GFG) project during 1999-2007. We found that water yield in 38% of the Loess Plateau area might have decreased (1-48 mm per year) as a result of land cover change alone. However, combined with climatic variability, 37% of the study area might have seen a decrease in water yield with a range of 1-54 mm per year, and 35% of the study area might have seen an increase with a range of 1-10 mm per year. Across the study region, climate variability masked or strengthened the water yield response to vegetation restoration. The absolute annual water yield change due to vegetation restoration varied with precipitation regimes with the highest in wet years, but the relative water yield changes were most pronounced in dry years. We concluded that the effects of land cover change associated with ecological restoration varied greatly over time and space and were strongly influenced by climatic variability in the arid region. The current regional vegetation restoration projects have variable effects on local water resources across the region. Land management planning must consider the influences of spatial climate variability and long-term climate change on water yield to be more effective for achieving environmental sustainability.
Abstract Platelet-derived growth factor-AA (PDGF-AA) has been used as a potent mitogen for the proliferation of oligodendrocyte progenitor cells (OPCs). Whether it plays a role in oligodendrocyte ...lineage differentiation of neural stem cells (NSCs) is unclear. Here we report that PDGF-AA is an instructional signal required for the differentiation of embryonic forebrain NSCs into O4-positive oligodendrocytes. Moreover, such PDGF-AA-induced oligodendrocyte differentiation appears to be mediated by the extracellular signal-regulated kinases 1 and 2 (Erk1/2) but not phosphatidylinositol-3 kinase (PI3K) pathway. Finally, PDGF-AA treatment resulted in a significant increase in the expression of the oligodendrocyte-specific transcriptional factor Olig2 in an Erk1/2-dependent mechanism at early stages of oligodendrogliogenesis. Together, our studies provide cellular and molecular evidence to suggest that PDGF-AA is a key molecule that regulates the differentiation of embryonic NSCs into oligodendrocytes. The action of PDGF-AA is mediated by the activation of Erk pathway which involves the downstream upregulation of transcriptional factor Olig2.
The possible grain refining candidates for Mg–Al alloys that may occur in the superheating process have been systematically studied from a crystallographic perspective. The edge-to-edge matching ...model was used to investigate and compare the grain refining efficiency of various (Al, Mn) containing phases existing in the melt. The results show that the metastable τ-AlMn phase possesses significantly better crystallographic matching to the Mg matrix than the other Al–Mn intermetallic phases and could therefore serve as an effective heterogenous nucleation site. However, since the metastable τ-AlMn phase can only be generated from the high temperature ε-AlMn phase through a massive transformation, overheating the melt is necessary to produce the high temperature ε-AlMn phase. During the subsequent cooling to pouring temperatures, the ε-AlMn phase will partially or fully transform into the τ-AlMn phase, which in turn can act as a nucleation site. The rapid cooling and the short isothermal holding time prevent it from further transforming into the equilibrium Al
8Mn
5 and β-Mn phases.
In micro-scaled plastic deformation or micro-forming process, workpiece usually consists of only a few grains in deformation zone. The so-called size effect thus exists and the material deformation ...behaviors are quite different from the conventional ones in macro-scaled. Size effect affects the deformation capability or the forming limit of sheet metals. To explore this effect, uniaxial tensile tests of different-shaped specimens were conducted to obtain the left-hand-side forming limit diagram of sheet metals from macro to micro-scaled. The deformation process was recorded by a digital camera and the limit strains of different deformation conditions were measured using the digital image correlation method. The left-hand-side forming limit diagrams under different thickness-to-grain-size ratio conditions were then constructed. The experimental results show the existence of the significant size effect and the forming limit decreases with the thickness-to-grain-size ratio. However, the scatter of forming limit gets much worse if there are only one or two grains over the thickness of material. To analyze how the size effect affects the ductile fracture in micro-forming, Oyane׳s ductile failure criterion was modified to model the forming limit in micro-scaled plastic deformation. Through calculation, the modified criterion is found to be able to model the decrease of forming limit caused by size effect. The revised Oyane criterion can then be used to analyze the forming limit of sheet metals in micro-scale.
•The setups of forming limit testing were developed for meso scale sheet metals.•The forming limit curves (FLC) were developed for pure copper sheets.•The FLC shifts down with the decrease of ...thickness-to-grain-size ratio.•The GTN–Thomason coupled model was extended by considering the size effect.•The FLCs predicted based on the model agree with the experimental ones.
Ductile fracture of metallic materials in micro/meso scale plastic deformation is influenced by geometry and grain sizes and the so-called size effect thus exists. To reveal how the size effect affects the formability of sheet metals in micro/meso scale plastic deformation, the forming limit of sheet metals was studied by experiment and modeling. An extended coupled damage model was first developed based on the Gurson–Tvergaard–Needleman and the Thomason models via considering the geometry and grain size effects on void evolution. In modeling process, the void nucleation was analyzed by taking account the phenomenon that the number of voids decreases with the ratio of thickness to grain size of workpiece. For the void growth, the widely used surface layer model was employed to describe the size effect on the flow stress of material. The grain size effect on void spatial arrangement was also modeled during the coalescence of micro voids. The model was then implemented into finite element simulations and the predicted forming limit curves under different scale factors were constructed. On the other hand, the forming limit experiments were conducted based on the miniaturized Holmberg and Marciniak tests to estimate the formability of sheet metals under different conditions. Both the physical experiments and finite element simulations show a significant size effect on the micro/meso scaled fracture behavior: The forming limit curve shifts down with the decreasing ratio of the thickness to grain size. The simulation results were also corroborated and verified by experiments. In addition, when the ratio is two or less than two, the very scattered limit strain results are observed in the experiments and the strain localization tends to occur at the beginning of deformation. The research conducted advances the understanding of size effect on the formability of micro/meso scaled sheet metals and thus helps the development of the successful and reliable microforming processes.
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