Benchmarking the Activity,Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

Anodically electrodeposited amorphous molybdenum sulfide (AE‐MoS_x) has attracted significant attention as a non‐noble metal electrocatalyst for its high activity toward the hydrogen evolution reaction (HER). The [Mo₃S₁₃]^2? polymer‐based structure confers a high density of exposed sulfur moieties, widely regarded as the HER active sites. However, their intrinsic complexity conceals full understanding of their exact role in HER catalysis, hampering their full potential for water splitting applications. In this report, a unifying approach is adopted accounting for modifications in the inherent electrochemistry (EC), HER mechanism, and surface species to maximize the AE‐MoS_x electroactivity over a broad pH region (0–10). Dramatic enhancements in HER performance by selective electrochemical cycling within reductive (overpotential shift, η_HER ≈ ?350 mV) and electro‐oxidative windows (η_HER ≈ ?290 mV) are accompanied by highly stable performance in mildly acidic electrolytes. Joint analysis of X‐ray photoelectron spectroscopy, Raman, and EC experiments corroborate the key role of bridging and terminal S ligands as active site generators at low pH, and reveal molybdenum oxysulfides (Mo⁵⁺O_xS_y) to be the most active HER moiety in AE‐MoS_x in mildly acidic‐to‐neutral environments. These findings will be extremely beneficial for future tailoring of MoS_x materials and their implementation in commercial electrolyzer technologies.     

内皮细胞特异性启动子pvWF和pVE的克隆及表达

目的:克隆并验证内皮细胞(Endothelial Cells,ECs)特异性启动子,为转染人胚胎干细胞(h ESC)后实时监测ECs的定向分化情况以及利用干细胞实施血友病A的基因治疗研究提供基础。方法:通过酶消化法原代分离人脐静脉内皮细胞(HUVECs),结合RT-PCR和免疫荧光验证分离后的HUVECs表达内皮细胞特异性标志基因血管性血友病因子(v WF)和血管内皮钙粘素(VE-cadherin/CDH5)。抽提HUVECs的g DNA,通过PCR扩增内皮细胞特异性表达基因v WF和VE-cadherin转录起始位点上游不同大小的启动子片段,将其取代报告基因载体p EGFP-N1中的广谱启动子CMV,构建4个质粒,即pv WF-1、pv WF-2、p VE-1、p VE-2,分别转染HUVECs和h ESCs,48 h后观察并比较各启动子片段启动绿色荧光蛋白GFP表达情况,筛选最具特异性及转录活性的启动子片段。结果:通过酶消化法,本研究成功分离出具有典型上皮样细胞的HUVECs。RT-PCR和免疫荧光结果表明HUVECs特异性表达v WF和VE-cadherin。酶切及测序证实所构建的4个含ECs特异性启动子片段的质粒与理论序列相符,通过核转染至HUVECs及h ESCs后,48 h后观察到所克隆的VE-cadherin 2105bp启动子片段具有内皮细胞表达的特异性和较强的转录活性。结论:本研究成功筛选出具有内皮细胞表达特异性及较强转录活性的启动子片段。     

抗生素单剂与联合治疗社区获得性肺炎的临床疗效观察

目的:观察β内酰胺类联合大环内酯类与β内酰胺类单剂治疗社区获得性肺炎的临床疗效。方法:收集我院呼吸内科住院的社区获得性肺炎患者262例,随机分为单剂治疗组和联合治疗组。两组患者均给予抗感染、对症支持治疗,其中单剂治疗组抗生素采用β内酰胺酶类单剂治疗,联合治疗组采用β内酰胺酶类和大环内酯类联合治疗。所有患者统计年龄、性别、基础疾病、病情严重程度,并记录治疗前与治疗后不同住院天数的血常规、C反应蛋白的变化,统计住院天数。结果:联合治疗患者一般基本情况(年龄、性别、基础疾病、病情严重程度)与单剂治疗组相比,P0.05,差异均无统计学意义。治疗前及治疗后首日C反应蛋白和白细胞计数二者相比,P0.05,差异均无统计学意义;联合治疗组与单剂治疗组相比,C反应蛋白在住院第2、4、6、9天,白细胞计数在住院第2、4、6天,均明显下降,住院天数缩短,P0.05,差异均有统计学意义。对于中、重度CAP(CRB65≥2),联合治疗组与单剂治疗组相比,治疗后C反应蛋白以及白细胞计数明显减少,P均0.05,差异有统计学意义;对于轻度CAP(CRB65=0~1),两组治疗后CRB和白细胞计数相比,P均0.05,差异无统计学意义。结论:β内酰胺类联合大环内酯类治疗治疗社区获得性肺炎临床疗效优于β内酰胺类单剂治疗。     

Prediction of the non-fertilizer N supply of mineral grassland soils

Different methods for estimating the non-fertilizer N supply (NFNS) of mineral grassland soils were compared. NFNS was defined as the N uptake on unfertilized plots. The potential mineralization rate (0–12 weeks), macroorganic matter and active microbial biomass (determined by the substrate-induced respiration method; SIR) were correlated positively with NFNS. The difference between the actual soil organic N or microbial N content (determined by the fumigation incubation method) and their contents under equilibrium conditions ( org. N and MB-N), however, gave the best estimations of NFNS. For field conditions the best estimation for NFNS was: NFNS (kg N ha^–1 yr^–1)=132.3+42.1× org. N (g kg^–1 soil; r=0.80). This method is based on the observation that, under old grassland swards, close relationships exist between soil texture and the amounts of soil organic N and microbial N. These relationships are assumed to represent equilibrium conditions as under old swards under constant management, the gain in soil organic N and microbial N equals the losses. Soils under young grassland and recently reclaimed soils contained less soil organic N and microbial N. In such soils the amounts of organic N and microbial N increase with time, which is reflected in a lower NFNS. The annual accumulation of organic and microbial N gradually becomes smaller until organic N, microbial N and NFNS reach equilibrium. The main advantage of the difference method in comparison with the other methods is its speed and simplicity.FAX no: +31 50337291     

Chemical modification of active sites in relation to the catalytic mechanism of F1

Recent studies of chemically modified F₁-ATPases have provided new information that requires a revision of our thinking on their catalytic mechanism. One of the subunits in F₁-ATPase is distinguishable from the other two both structurally and functionally. The catalytic site and regulatory site of the same subunit are probably sufficiently close to each other, and the interaction between the various catalytic and regulatory sites are probably sufficiently strong to raise the uni-site rate of ATP hydrolysis by several orders of magnitude to that of promoted (multi-site) ATP hydrolysis. Although all three subunits in F₁ possess weak uni-site ATPase activity, only one of them () catalyzes promoted ATP hydrolysis. But all three subunits catalyze ATP synthesis driven by the proton flux. Internal rotation of the ₃₃ or ₃ moiety relative to the remainder of the F₀F₁ complex did not occur during oxidative phosphorylation by reconstituted submitochondrial particles.     

Effect of Electroconvulsive Shock on Mitochondrial Respiratory Chain in Rat Brain

It is well described that impairment of energy production has been implicated in the pathogenesis of a number of diseases. Although several advances have occurred over the past 20 years concerning the use and administration of electroconvulsive therapy (ECT) to minimize its side effects, little progress has been made in understanding its mechanism of action. In this work, our aim was to measure the activities of mitochondrial respiratory chain complexes II and IV and succinate dehydrogenase from rat brain after acute and chronic electroconvulsive shock (ECS). Our results showed that mitochondrial respiratory chain enzymes activities were increased after acute ECS in hippocampus, striatum and cortex of rats. Besides, we also demonstrated that complex II activity was increased after chronic ECS in cortex, while hippocampus and striatum were not affected. Succinate dehydrogenase, however, was inhibited after chronic ECS in striatum, activated in cortex and not affected in hippocampus. Finally, complex IV was not affected by chronic ECS in hippocampus, striatum and cortex. Our findings demonstrated that brain metabolism is altered by ECS.     

Effects of the head lift exercise on the swallow function: a systematic review

doi: 10.1111/j.1741‐2358.2012.00638.x Effects of the head lift exercise on the swallow function: a systematic review Objective: Ageing is associated with modifications in upper oesophageal sphincter function that may be deleterious to deglutition. The head lift exercise (Shaker exercise) is a head‐raising work out aiming to improve the opening of this segment, and ultimately to reduce aspiration. We aimed to review critically the evidence on the effects of this structured intervention programme and to identify gaps to be filled by future research. Material and Methods: We identified published reports addressing the effect of this exercise in increasing the anteroposterior diameter and cross‐sectional area of the deglutitive upper oesophageal sphincter opening or dysphagic symptoms. Results: Nine methodologically heterogeneous studies were included in the review, and the reported effects of the head lift exercise were an increase in the anterior excursion of the larynx and in the anteroposterior diameter of the upper oesophageal sphincter opening, and the elimination of dysphagic symptoms. Conclusion: Further studies including control groups and accounting for potential confounders are needed for a sound assessment of the effectiveness of this technique. The data on the functional results are, however, promising for dysphagia interventions.