Precisely Control Relationship between Sulfur Vacancy and H Absorption for Boosting Hydrogen Evolution Reaction

Ef fective and robust catalyst is the core of water splitting to produce hydrogen.Here, we report an anionic etching method to tailor the sulfur vacancy(VS) of NiS_(2) to further enhance the electrocatalytic performance for hydrogen evolution reaction(HER). With the VS concentration change from 2.4% to 8.5%, the H* adsorption strength on S sites changed and NiS_(2)-VS 5.9% shows the most optimized H* adsorption for HER with an ultralow onset potential(68 m V) and has long-term stability for 100 h in 1 M KOH media. In situ attenuated-total-reflection Fourier transform infrared spectroscopy(ATR-FTIRS) measurements are usually used to monitor the adsorption of intermediates. The S-H* peak of the Ni S_(2)-VS 5.9% appears at a very low voltage, which is favorable for the HER in alkaline media. Density functional theory calculations also demonstrate the Ni S_(2)-VS 5.9% has the optimal |ΔG^(H*)| of 0.17 e V. This work offers a simple and promising pathway to enhance catalytic activity via precise vacancies strategy.

Chemical constituents and pharmacological effects of Croton crassifolius

Croton crassifolius(CC)is a kind of traditional Chinese medicine rich in terpenoids,with among which diterpene species are the most.CC had biological activities in the treatment of cancer,inflammation,ulcerative colitis,osteoporosis and Alzheimer’s disease.This study reviews the chemical compositions and pharmacological activities of CC to provide reference for further research.

Chemical composition and biological activity of Houttuynia cordata

Houttuynia cordata is an important traditional Chinese medicine.It is widely used for clearing heat and detoxification,reducing swelling and treating sores,diuresis and dehumidification.It is also used to treat lung carbuncles,ulcers,hemorrhoids,rectal bleeding,spleen and stomach heat,which are caused by excess heat,heat toxicity,dampness,and disease heat.Modern pharmacological experiments have shown that H.cordata has antibacterial,antiviral,immune enhancing,diuretic and other effects.This article reviews the chemical components and biological activities of H.cordata to provide reference for clinical application.

Chemical composition and biological activities of volatile oil isolated from Curcumae rhizoma

Curcumae rhizoma(C.rhizoma),the rhizome of Curcuma Longa L.,Curcuma kwangsiensis L.and Curcuma wenyujin L.in the ginger family,is a treasure in traditional Chinese medicine.It has the effect of promoting qi and breaking blood,eliminating accumulation and relieving pain.With the development of modern medicine,the active ingredients and therapeutic mechanism of C.rhizoma have been gradually revealed.In this paper,the chemical composition and biological activities of volatile oil isolated from C.rhizoma are reviewed in detail,aiming to provide reference for further utilization of C.rhizoma volatile oil and provide more effective drug options for clinical treatment.

Overexpression of microRNA-135b-5p attenuates acute myocardial infarction injury through its anti-oxidant and anti-apptotic properties

Objective:Myocardial infarction(MI)remains the leading cause of morbidity and mortality due partly to the limited regenerative capacity of cardiomyocytes to replace cardiomyocyte lost due to apoptosis.Inhibiting cardiomyocyte apoptosis is recognized as an effective therapeutic approach for MI.MicroRNAs(miRNAs,miRs),which regulate target genes at the post-transcriptional level,play a significant role in the regulation of cardiovascular diseases such as MI.MicroRNA-135b(miR-135b)has a protective effect on cardiomyocytes.However,the role of miR-135b in cardiomyocyte apoptosis in infarct myocardium needs further clarification.Methods:We generatedα-MHC-miR-135b transgenic mice to investigate the role of miR-135b in myocardial injury after MI.MiR-135b mimic and negative control(NC)were transfected into H2O2-induced cardiomyocytes to evaluate the effect of overexpression of miR-135b on the levels of reactive oxygen species(ROS)and apoptosis.Results:Our results showed that overexpression of miR-135b had protective effect on cardiomyocyte injury both in vivo and in vitro.MiR-135b inhibited cardiomyocyte apoptosis and ROS generation,downregulated pro-apoptosis proteins(cleaved-caspase-3 and Bax),and increased anti-apoptosis protein(Bcl-2).Moreover,miR-135b showed an inhibitory effect on apoptosis-related protein target transient receptor potential vanilloid-type 4(TRPV4)cation channel.Conclusion:MiR-135b might be considered a new molecular target for potential replacement therapy as antiapoptotic cardioprotection in the setting of MI.

Design of mesoporous ZnCoSiOx hollow nanoreactors with specific spatial distribution of metal species for selective CO_(2)hydrogenation

In heterogeneous catalysis,the precise placement of active components to perform unique functions in cooperation with each other is a tremendous challenge.The migration of matter on micro/nano-scale caused by diffusion is a promising pathway for design of catalytic nanoreactors with precise active sites location and controllable microenvironment through compartmentalization and confinement effects.Herein,we report two categories of mesoporous ZnCoSiOx hollow nanoreactors with different metal distributions and microenvironment engineered by the diffusion behavior of metal species in confined nanospace.Double-shelled hollow structures with well-distributed metal species were obtained by adopting core@shell structured ZnCo-zeolitic imidazolate framework(ZIF)@SiO2 as a template and employing three stages of hydrothermal treatment including the decomposition of ZIF,diffusion of metal species into the silica shell,and Ostwald ripening.Additionally,the formation of yolk@shell structure with a collective(Zn-Co)metal oxide as the yolk was achieved by direct pyrolysis of ZnCo-ZIF@SiO2.In CO_(2)hydrogenation,ZnCoSiOx with double-shelled hollow structures and yolk@shell structures respectively afford CO and CH_(4)as main product,which is related with different dispersion and location of active sites in the two catalysts.This study provides an efficient method for the synthesis of catalytic nanoreactors on the basis of insights of the atomic diffusion in confined space at the mesoscale.

On optimization of cooperative MIMO for underlaid secrecy Industrial Internet of Things

In this paper,physical layer security techniques are investigated for cooperative multi-input multi-output(C-MIMO),which operates as an underlaid cognitive radio system that coexists with a primary user(PU).The underlaid secrecy paradigm is enabled by improving the secrecy rate towards the C-MIMO receiver and reducing the interference towards the PU.Such a communication model is especially suitable for implementing Industrial Internet of Things(IIoT)systems in the unlicensed spectrum,which can trade off spectral efficiency and information secrecy.To this end,we propose an eigenspace-adaptive precoding(EAP)method and formulate the secrecy rate optimization problem,which is subject to both the single device power constraint and the interference power constraint.This precoder design is enabled by decomposing the original optimization problem into eigenspace selection and power allocation sub-problems.Herein,the eigenvectors are adaptively selected by the transmitter according to the channel conditions of the underlaid users and the PUs.In addition,a simplified EAP method is proposed for large-dimensional C-MIMO transmission,exploiting the additional spatial degree of freedom for a low-complexity secrecy precoder design.Numerical results show that by transmitting signal and artificial noise in the properly selected eigenspace,C-MIMO can eliminate the secrecy outage and outperforms the fixed eigenspace precoding methods.Moreover,the proposed simplified EAP method for the large-dimensional C-MIMO can significantly improve the secrecy rate.

Potential risk of colonization of Bulinus globosus in the mainland of China under climate change

Background: Bulinus globosus,the main intermediate snail host of Schistosoma haematobium.The increased contacts between Africa and China could even lead to large-scale dissemination of B.globosus in China.Temperature is the key factor affecting fresh-water snail transmission.This study predicted potential risk of colonization of B.globosus in the mainland of China under climate change.Methods: We investigated minimum and maximum temperatures for B.globosus eggs,juveniles and adult snails kept under laboratory conditions to find the most suitable range by pinpointing the median effective temperatures(ET50).We also assessed the influence of temperature on spawning and estimated the accumulated temperature(AT).The average air temperatures between 1955 and 2019 in January and July,the coldest and hottest months in China,respectively,were collected from national meteorological monitoring stations and investigated in a geographic information system(GIS)using empirical Bayesian Kriging to evaluate the theoretical possibility for distribution of B.globosus in southern China based on temperature.Results: The effective minimum temperature(ET50min)for eggs,juveniles,adult snails and spawning were 8.5,7.0,7.0,14.9℃,respectively,with the corresponding maximum values(ET50max)of 36.6,40.5,40.2 and 38.1℃.The AT was calculated at 712.1±64.9℃·d.In 1955,the potential B.globosus distribution would have had a northern boundary stretching from the coastal areas of Guangdong Province and Guangxi Autonomous Region to southern Yunnan Province.Since then,this line has gradually moved northward.Conclusions: Annual regeneration of B.globosus can be supported by the current climate conditions in the mainland of China,and a gradual expansion trend from south to north is shown in the study from 2015 to 2019.Thus,there is a potential risk of colonization of B.globosus in the mainland of China under climate change.

Cobalt-Catalyzed Intermolecular Hydroamination of Unactivated Alkenes Using NFSI as Nitrogen Source

Cheap metal(Fe,Mn,and Co)-catalyzed hydroamination of alkenes has been an attractive method for synthesis of amines because of biocompatibility of metal,excellent Markovnikov selectivity and chemoselectivity.However,most reports are limited to unsaturated nitrogen sources(nitric oxide,azos,azides,cyano,etc.),for which aminated products are very limited.Notably,while used widely for fluorinating reaction,N-fluorobenzenesulfonimide(NFsI)as amine source for hydroamination has seldom been reported.Here we developed a cobalt-catalyzed intermolecular hydroamination of unactivated alkenes using NFSl as nitrogen source under mild conditions.The reaction exhibits excellent chemo-and regio-selectivity with no hydrofluorination or linear-selectivity products.Notably,the reaction proceeded with excellent yield even though the amount of Co(salen)catalyst was reduced to 0.2 mol%.Recently,a similar work was also reported by Zhang and coworkers(ref.19).