Strong metal–support interaction boosts the electrocatalytic hydrogen evolution capability of Ru nanoparticles supported on titanium nitride

Ruthenium(Ru)has been regarded as one of the most promising alternatives to substitute Pt for catalyzing alkaline hydrogen evolution reaction(HER),owing to its inherent high activity and being the cheapest platinum-group metal.Herein,based on the idea of strong metal–support interaction(SMSI)regulation,Ru/TiN catalysts with different degrees of TiN overlayer over Ru nanoparticles were fabricated,which were applied to the alkaline electrolytic water.Characterizations reveal that the TiN overlayer would gradually encapsulate the Ru nanoparticles and induce more electron transfer from Ru nanoparticles to TiN support by the Ru–N–Ti bond as the SMSI degree increased.Further study shows that the exposed Ru–TiN interfaces greatly promote the H_(2) desorption capacity.Thus,the Ru/TiN-300 with a moderate SMSI degree exhibits excellent HER performance,with an overpotential of 38 mV at 10 mA cm^(−2).Also,due to the encapsulation role of TiN overlayer on Ru nanoparticles,it displays super long-term stability with a very slight potential change after 24 h.This study provides a deep insight into the influence of the SMSI effect between Ru and TiN on HER and offers a novel approach for preparing efficient and stable HER electrocatalysts through SMSI engineering.

Optimizing 3d spin polarization of CoOOH by in situ Mo doping for efficient oxygen evolution reaction

Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts.Herein,Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mAcm−2.Additionally,it had an overpotential of 260 mV(glassy carbon)or 215 mV(nickel foam),which was 78 mV lower than that of IrO_(2)(338 mV).In situ,Raman spectroscopy revealed the transformation process of CoOOH.Calculations using the density functional theory showed that during OER,doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process,which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials.Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.

Two-dimensional face stability analysis in rock masses governed by the Hoek-Brown strength criterion with a new multi-horn mechanism

The face stability problem is a major concern for tunnels excavated in rock masses governed by the Hoek-Brown strength criterion.To provide an accurate prediction for the theoretical solution of the critical face pressure,this study adopts the piecewise linear method(PLM)to account for the nonlinearity of the strength envelope and proposes a new multi-horn rotational mechanism based on the Hoek-Brown strength criterion and the associative flow rule.The analytical solution of critical support pressure is derived from the energy-work balance equation in the framework of the plastic limit theorem;it is formulated as a multivariable nonlinear optimization problem relying on 2m dependent variables(m is the number of segments).Meanwhile,two classic linearized measures,the generalized tangential technique(GTT)and equivalent Mohr-Coulomb parameters method(EMM),are incorporated into the analysis for comparison.Surprisingly,the parametric study indicates a significant improvement in support pressure by up to 13%compared with the GTT,and as expected,the stability of the tunnel face is greatly influenced by the rock strength parameters.The stress distribution on the rupture surface is calculated to gain an intuitive understanding of the failure at the limit state.Although the limit analysis is incapable of calculating the true stress distribution in rock masses,a rough approximation of the stress vector on the rupture surface is permitted.In the end,sets of normalized face pressure are provided in the form of charts for a quick assessment of face stability in rock masses.

Control of epileptic activities in a cortex network of multiple coupled neural populations under electromagnetic induction

Epilepsy is believed to be associated with the abnormal synchronous neuronal activity in the brain,which results from large groups or circuits of neurons.In this paper,we choose to focus on the temporal lobe epilepsy,and establish a cortex network of multiple coupled neural populations to explore the epileptic activities under electromagnetic induction.We demonstrate that the epileptic activities can be controlled and modulated by electromagnetic induction and coupling among regions.In certain regions,these two types of control are observed to show exactly reverse effects.The results show that the strong electromagnetic induction is conducive to eliminating the epileptic seizures.The coupling among regions has a conduction effect that the previous normal background activity of the region gives way to the epileptic discharge,owing to coupling with spike wave discharge regions.Overall,these results highlight the role of electromagnetic induction and coupling among the regions in controlling and modulating epileptic activities,and might provide novel insights into the treatments of epilepsy.

血清胆固醇水平与卒中后认知障碍相关性研究

目的:探讨血清胆固醇水平及其动态变化与卒中后认知障碍(PSCI)之间的关系。方法:招募首次急性缺血性脑卒中患者。在卒中发病3~6个月后使用蒙特利尔认知量表(MoCA)评估患者的认知功能,分为PSCI组和无PSCI组,比较两组血清胆固醇基线和3~6个月随访时水平及其变化值。采用了Pearson相关分析和logistic回归分析探索血清胆固醇水平与PSCI的关系。结果:本研究纳入107例患者,其中PSCI组46例,无PSCI组61例。PSCI患者随访时血清总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)水平明显高于无PSCI组患者(3.74±1.04 vs 3.38±0.76,P=0.042;2.20±0.96 vs 1.87±0.67,P=0.039),且指标下降幅度小,但是无统计学意义(P>0.05)。PSCI组患者随访时血清TC水平(r=-0.332,P=0.024)及其变化值(r=-0.334,P=0.023)、LDL-C水平(r=-0.316,P=0.032)及其变化值(r=-0.332,P=0.024)均与延迟回忆呈负相关。单因素回归分析中显示卒中后3~6个月时的LDL-C水平(OR:1.687,95%CI:1.004-2.835,P=0.048)和TC水平(OR:1.609,95%CI:0.997-2.598,P=0.052)与PSCI有关,调整混杂因素后无统计学差异(P>0.05)。结论:在卒中发病3~6个月时,患者血清LDL-C及TC水平与PSCI之间存在着相关性,且与延迟回忆呈负相关,而血清胆固醇变化值与PSCI无相关性。

A Survey of Testing for 5G:Solutions,Opportunities,and Challenges

With the development of wireless communication technology,the fifth generation mobile communications system(5 G) emerges at a historic moment and devotes itself to open the curtain of the information age.Recently,in order to satisfy the requirement of different applications,various advanced 5 G technologies have been developed in full swing.However,before applying these 5 G related technologies in practical systems,effective testing methods are needed to evaluate these technologies in a real,comprehensive,rapid and flexible manner.However,the testing methods are faced with new challenges along with the continuous development of the new 5 G technologies.In this paper,we present a survey of 5 G testing,including solutions and opportunities.In particular,two cases are considered,i.e.,channel modelling and overthe-air(OTA) testing of antenna systems.Specifically,a non-stationary channel model is proposed to characterize and test massive multiple-input multiple-output(MIMO) channel.In addition,we propose two probe subset selection algorithms for three-dimensional(3 D) OTA testing,which minimizes the number of probe antennas while ensuring the accuracy of the target channel emulation.Finally,future research directions and challenges on 5 G testing are given.

Designing of highly selective and high-temperature endurable RWGS heterogeneous catalysts: recent advances and the future directions

Reverse water gas shift（RWGS） reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually significance in enabling a rebuilt ecological system for unconventional fuels. This concept is appealing when the process is considered as a solution for the storage of renewable energy, which may also find a variety of potential end uses for the outer space exploration. However, a big challenge to this issue is the rational design of high temperature endurable RWGS catalysts with desirable CO product selectivity. In this work, we present a comprehensive overview of recent publications on this research topic,mainly focusing on the catalytic performance of RWGS reaction over three major kinds of heterogeneous catalysts, including supported metal catalysts, mixed oxide catalysts and transition metal carbides. The reaction thermodynamic analysis, kinetics and mechanisms are also described in detail. The present review attempts to provide a general guideline about the construction of well-performed heterogeneous catalysts for the RWGS reaction, as well as discussing the challenges and further prospects of this process.

Differences in brain structure in patients with distinct sites of chronic pain:A voxel-based morphometric analysis

A reduction in gray matter volume is common in patients with chronic back pain, and different types of pain are associated with gray matter abnormalities in distinct brain regions. To examine differ- ences in brain morphology in patients with low back pain or neck and upper back pain, we investi- gated changes in gray matter volume in chronic back pain patients having different sites of pain using voxel-based morphometry. A reduction in cortical gray matter volume was found primarily in the left postcentral gyrus and in the left precuneus and bilateral cuneal cortex of patients with low back pain. In these patients, there was an increase in subcortical gray matter volume in the bilateral putamen and accumbens, right pallidum, right caudate nucleus, and left amygdala. In upper back pain patients, reduced cortical gray matter volume was found in the left precentral and left postcen- tral cortices. Our findings suggest that regional gray matter volume abnormalities in low back pain patients are more extensive than in upper back pain patients. Subcortical gray matter volume in- creases are found only in patients with low back pain.

Direct conversion of syngas to aromatics: A review of recent studies

The direct catalytic conversion of syngas to aromatics offers a promising route to manufacture fine chemicals by employing non-petroleum carbon resources,because aromatic constituents are the key platform for producing polymers.However,this remains a great challenge due to the low yield of aromatics and poor catalyst stability,which restrict further development.In recent years,extensive research has been reported on the design of effective catalysts and the optimization of operating conditions to obtain better catalytic performance.In this review,we focus on these related achievements and present a comprehensive overview of different kinds of catalysts,mainly including modified Fischer-Tropsch(FT)catalysts and composite catalysts,as well as their performance and reaction mechanisms.The thermodynamic analysis of the reactions involved in this innovative conversion process and the comparison of different methods are also described in detail in this updated review.Finally,the challenges and prospects for direct syngas conversion are discussed to provide general guidelines for the construction of a well-designed reaction route.

The influence of intimacy on the ’iterative reactions’ during OX-ZEO process for aromatic production

The oxide-zeolite process provides a promising way for one-step production of aromatics from syngas,whereas the reasons for the dramatic effect of intimacy between oxide and zeolite in the composite catalyst on the product selectivity are still unclear. In order to explore the optimal intimacy and the essential influence factors, ZnCrOxcombined with ZSM-5 are employed to prepare the composite catalysts with different distances between the two components by changing the mixing methods. An aromatic selectivity of 74%(with CO conversion to be 16%) is achieved by the composite catalyst when the intimacy is in the range of nanometer. A so-called ‘iterative reactions’ mechanism of intermediates over oxides is then proposed and studied: the intermediate chemical can undergo a hydrogenation reaction on oxide.So the shorter the intermediates stay on oxide, the more of chance for C-C coupling takes place on zeolite to form aromatics. Moreover, the aero-environments of reaction is found to impact on the extent of iterative reaction as well. Therefore, when the intimacy between the two components changes, the extent of iterative reactions vary, resulting in alteration of product distribution. This work provides new insight in understanding the mechanisms during the complex process of OX-ZEO composite catalysis and sheds light to the design of a high-yield catalyst for synthetization of aromatics from syngas.

Identification of relevant active sites and a mechanism study for reverse water gas shift reaction over Pt/CeO_2 catalysts

Reverse water gas shift (RWGS) reaction can serve as a pivotal stage in the CO2 conversion processes, which is vital for the utilization of CO2. In this study, RWGS reaction was performed over Pt/CeO2 catalysts at the temperature range of 200-500 degrees C under ambient pressure. Compared with pure CeO2, Pt/CeO2 catalysts exhibited superior RWGS activity at lower reaction temperature. Meanwhile, the calculated TOF and E-a values are approximately the same over these Pt/CeO2 catalysts pretreated under various calcination conditions, indicating that the RWGS reaction is not affected by the morphologies of anchored Pt nanoparticles or the primary crystallinity of CeO2. TPR and XPS results indicated that the incorporation of Pt promoted the reducibility of CeO2 support and remarkably increased the content of Ce 3 + sites on the catalyst surface. Furthermore, the CO TPSR-MS signal under the condition of pure CO2 flow over Pt/CeO 2 catalyst is far lower than that under the condition of adsorbed CO2 with H-2 -assisted flow, revealing that CO2 molecules adsorbed on Ce3+ active sites have difficult in generating CO directly. Meanwhile, the adsorbed CO2 with the assistance of H-2 can form formate species easily over Ce3+ active sites and then decompose into Ce3+-CO species for CO production, which was identified by in-situ FTIR. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.

Hydrological response to land use and land cover changes in a sub-watershed of West Liaohe River Basin,China

In recent years, the streamflow of the Laohahe Basin in China showed a dramatic decrease during the rainy season as a result of climate change and/or human activities. The objective of this work was to document significant streamflow changes caused by land use and land cover （LULC） changes and to quantify the impacts of the observed changes in Laohahe Basin. in the study area, the observed streamflow has been influenced by LULC changes, dams, and irrigation from rivers, industry, livestock and human consumption. Most importantly, the growth of population and gross domestic product （GDP） accompanied by the growth in industrial and agricultural activities, which led to LULC changes with increased residential land and cropland and decreased grassland since 2000s. Statistical methods and Variable Infiltration Capacity （VIC） hydrological model were used to estimate the effects of climate change and LULC changes on streamflow and evaportranspiration lET）. First, the streamflow data of the study area were divided into three sub-periods according to the Pettitt test. The hydrological process was then simulated by VIC model from 1964 to 2009. Furthermore, we compared the simulated results based on land use scenarios in 1989, 1999 and 2007, respectively for exploring the effect of LULC changes on the spatio-temporal distribution of streamflow and ET in the Laohahe Basin. The results suggest that, accompanied with climate change, the LULC changes and human water consumption appeared to be the most likely factors contributing to the sig- nificant reduction in streamflow in the Laohahe Basin by 64% from1999 to 2009.

近三年国内近红外检测应用研究进展

近红外光谱检测属于无损、快速、绿色检测。近三年来,近红外光谱应用领域逐渐扩大,涉及林业、农业、食品、化工、医学、药学等。近红外光谱可以实现组分快速检测、品质鉴定、掺假分析、溯源、损伤检测、病害检测等。为了方便实际应用,食品、林业、农业领域设计/使用了便携设备,进一步促进近红外光谱技术的应用。食品、化工、药物生产领域,采用近红外光谱技术进行在线检测。

Conjugation with Acridines Turns Nuclear Localization Sequence into Highly Active Antimicrobial Peptide

The emergence of multidrug-resistant bacteria creates an urgent need for alternative antibiotics with new mechanisms of action. In this study, we synthesized a novel type of antimicrobial agent, Ac r_3-NLS, by conjugating hydrophobic acridines to the N-terminus of a nuclear localization sequence(NLS), a short cationic peptide. To further improve the antimicrobial activity of our agent, dimeric(Acr_3-NLS)_2 was simultaneously synthesized by joining two monomeric Acr_3-NLS together via a disulfide linker. Our results show that Acr_3-NLS and especially(Acr_3-NLS)_2 display signifi cant antimicrobial activity against gramnegative and gram-positive bacteria compared to that of the NLS. Subsequently, the results derived from the study on the mechanism of action demonstrate that Acr_3-NLS and(Acr_3-NLS)_2 can kill bacteria by membrane disruption and DNA binding. The double targets—cell membrane and intracellular DNA—will reduce the risk of bacteria developing resistance to Acr_3-NLS and(Acr_3-NLS)_2. Overall, this study provides a novel strategy to design highly eff ective antimicrobial agents with a dual mode of action for infection treatment.

Crosstalk between CpG Methylation and Polymorphisms (CpG-SNPs) in the Promotor Region of DIO2 in Kashin-Beck Disease

Objective This study was designed to determine the methylation profile of four CpGs and the genotypes of two CpG-SNPs located in promoter region of DIO2 in patients with Kashin-Beck disease(KBD).We also analyzed the interaction between the CpGs methylations and CpG-SNPs.Methods Whole blood specimens were collected from 16 KBD patients and 16 healthy subjects.Four CpGs and two CpG-SNPs in the promoter regions of DIO2 were detected using matrix-assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF-MS).The CpGs methylation levels were compared between samples from KBD patients and healthy subjects.The methylation levels were also analyzed in KBD patients with different CpG-SNP genotypes.Results The mRNA expression of DIO2 in whole blood of KBD patients was significnatly lower than in healthy controls(P<0.05).The methylation levels of DIO2-1_CpG_3 in KBD patients were significantly higher than those in healthy controls(P<0.05).The methylation levels of four CpGs were not significantly different between KBD patients and healthy controls.The methylation level of DIO2-1_CpG_3 in the promoter region of DIO2 in KBD patients with GA/AA genotype was significantly higher than that of KBD patients with GG genotype(P<0.05).Conclusion The methylation level of DIO2 increases in KBD patients.Similar trends exist in KBD carriers of variant genotypes of CpG-SNPs DIO2 rs955849187.

Preparation of Kenaf Biochar and Its Adsorption Properties for Methylene Blue

The toxic dyestuff's from printing and dyeing wastewater have caused serious damages to the ecological environ-ment,thus exploring effective methods to remove them having become a key topic.Here,a series of biochar sam-ples were synthesized form kenaf to adsorb methylene blue(MB),which was acted as the dye representative for the test of adsorption capacity due to the presence of abundant double bond and aroma tic heterocyclic ring.By tuning the raw materials and pyrolysis temperature,a super adsorption capacity about 164.21 mg·g^(-1) was obtained over the biochar that pyrolyzed at 700℃ with the kenaf fiber as raw material Through the physical adsorption,elemental analysis,FTIR spectra and NH_(3)-TPD,it was found the high surface area and pore volume of biochar played a key role in the adsorption of MB,and the acidic sites would also assist the adsorption process.Besides,the adsorption kinetic model was ftted and calculated,implying the MB physically adsorbed on the bio-char rapidly and then occurred chemical adsorption on the acidic sites.In addition,through KBC700 recycling experiments,it was found that kenaf biochar had a good binding force to MB,which effectively avoided secondary pollution.This work provides important insights for the adsorption mechanism of MB by biochar,also offers some guidance for the further synthesis of biochar from various biomass.

Mechanism insight into the enhanced photocatalytic purification of antibiotic through encapsulated architectures coupling of crystalline Cu_(2)O/amorphous TiFe layer double hydroxide

Amorphous materials are one of the important candidates for improving heterogeneous photocata-lysts because of their unique electronic structures and abundant catalytic sites originating from dis-order atomic arrangements.However,there is still much room for the development of new crys-talline/amorphous heterogeneous composites for photocatalytic application.Hence efficient synthetic strategies for preparing new crystalline/amorphous heterojunctions are highly desired.Herein,we have realized the deep optimization of photocatalytic activity by fabricating crystalline/amorphous Cu_(2)O/Ti-Fe layer double hydroxide(LDH)heterojunctions.Thanks to the typical Z-scheme mechanism originating from the crystalline/amorphous interfaces,the photocharge separation and catalytic active sites obviously enhance compared to single Cu_(2)O and LDH counterparts.As expected,the photocatalytic removal of tetra-cycline(TC)of the as-prepared Cu_(2)O/Ti-Fe LDH was over 5.2 and 2.2 times those of the pristine Cu_(2)O nanospheres and Ti-Fe LDH nanosheets.This work illustrates the origin of crystalline Cu_(2)O nanospheres encapsulated in amorphous Ti-Fe layer double hydroxide nanosheets for enhanced photocatalytic activity driven by visible light,and provide a general Cu_(2)O-templated solution-phase synthetic method for the synthesis of novel double-metal layer double hydroxide amorphous nanostructures.

红外测温仪在灭菌后物品冷却温度监测中的应用及效果评价

目的探讨红外测温仪在灭菌后物品冷却温度监测中的应用价值及效果。方法通过灭菌后物品冷却速度影响实验、常见5类灭菌包冷却时间实验及不同冷却温度与湿包发生关系实验,获取红外测温仪在灭菌后物品冷却温度监测中的参考数据,同时比较红外测温仪实际应用前后的效果。结果不同摆放层、不同包装材料、不同包内容物、不同重量与体积的手术包经灭菌卸载后的冷却速度以及常见5类灭菌包冷却至室温所需的时间各不相同,差异有统计学意义(P<0.05),经棉布包装的大件手术器械包,在不同冷却温度下湿包发生率不同,差异有统计学意义(P<0.05)。红外测温仪应用前后,湿包发生率以及消毒员在灭菌包冷却期间手接触灭菌包的平均次数比较,差异有统计学意义(P<0.05)。结论红外测温仪能为灭菌后物品的移行和发放提供客观准确的参考数据,实际应用后可减少湿包发生率,降低频繁接触污染的风险。

硒蛋白对人体健康重要作用的研究进展

硒(selenium,Se)是动物和人类健康所必需的微量元素,硒的缺乏会导致多种疾病的发生.硒在体内主要以硒蛋白的形式发挥生物学作用,目前硒蛋白与人体健康关系的研究日益受到重视.迄今人类已发现25种硒蛋白,本文重点对谷胱甘肽过氧化物酶(glutathione peroxidase,GPX)、硫氧还蛋白还原酶(thioredoxin reductase,TrxR)、碘甲状腺氨酸脱碘酶(iodothyronine deiodinase,ID)家族的结构和生物学功能及其与疾病关系等方面进行了综述,表明GPX、TrxR、ID等硒蛋白具有抗氧化、抗炎症、抗细胞凋亡,参与甲状腺激素代谢,调节机体代谢等生物学功能,可通过遗传与表观遗传等多种形式在肿瘤、心血管疾病、骨关节炎、地方病以及新型冠状病毒肺炎等疾病的发病机制及防治方面起重要作用.本文为进一步揭示硒蛋白在人体健康中的作用及筛选疾病防治靶标提供新的线索和依据.

Effect of Huanglian Jiedu Decoction on vascular endothelium factor and expression of RhoA protein factor in young spontaneously hypertensive rats

To investigate the mechanism of effect of Huanglian Jiedu Decoction(HLJD) on vascular endothelium, we assessed the protective effect of HLJD on vascular endothelium in spontaneously hypertensive rats(SHR) and the expression of RhoA in thoracic aorta. A total of 40 SHR rats were randomly and evenly divided into model group(SHR group), positive group(captopril group), HLJD high-dose group, and HLJD low-dose group. Simultaneously, 10 Wistar Kyoto rats were used in the blank group. All groups were treated by gavage for 6 weeks. The changes of nitric oxide synthase(NOS), von Willebrand factor(vWF), endothelin(ET-1) and calmodulin(CAM) in rat serum were tested by enzyme linked immunosorbent assay(ELISA) method. The expression of RhoA at the protein and mRNA levels in thoracic aorta was determined by Western blotting(WB) and quantitative real-time PCR, respectively. Compare with the blank group after 6 weeks, the levels of ET-l and VWF in serum of the model group were significantly increased(P<0.01), and the levels of NOS and CAM were significantly decreased(P<0.01). Conversely, the levels of ET-1 and vWF in the positive and HLJD groups were significantly decreased(P<0.01 or P<0.05), and the levels of NOS and CAM were significantly increased(P<0.01 or P<0.05) compared with the model group. The expression of Rho A at the mRNA and protein levels was decreased obviously(P<0.05) in HLJD high-dose group. The results shown that HLJD increased diastolic factor(CAM and NOS) in the vascular endothelial of rats, leading to reduced contraction factor(ET-1 and vWF). HLJD revealed the preventive function in the vascular endothelial dysfunction of the early stage hypertension through adjusting secretion of blood vessel endothelium(BVE) relaxing factor and improving vascular endothelial function. The mechanism might be associated with the inhibition of the activity of RhoA protein factor.