面式、经式异构体的钴-氨基硫脲配合物作为催化剂应用于可见光催化分解水产氢（英文）

近年来,作为替代贵金属铂催化剂的铁、钴和镍等非贵金属配合物分子催化剂,由于合成容易、结构调控方便以及具有良好的催化活性等特点,成为均相光催化分解水产氢领域的研究热点.其中,钴配合物具有结构简单、成本低廉、容易合成以及具有理想的氧化还原电位等优势,更是光催化分解水产氢领域的优先研究对象.由于稳定性及溶解度的问题,在已报道的研究工作中,大部分钴配合物测试环境均在有机溶剂或有机溶剂/水混合溶剂中.因此,寻找水溶性良好的钴配合物催化剂成为了目前的均相光催化分解水产氢领域的研究焦点之一.在此之前,氨基硫脲配合物已经广泛用于生物和制药等研究,例如:抗氧化、抗菌以及抗病毒等领域.而在人工光合产氢领域采用氨基硫脲配合物作为催化剂的例子则比较罕见.在该项研究中,我们报道了一对水溶性较好(>40 mg mL^(–1),20°C)且具有几何异构特征的八面体钴-氨基硫脲配合物作为光、电催化质子还原产氢的分子催化剂.这对几何异构体分别为:面式异构体[Co(Htsc)_3]Cl_3·3H_2O(C1,Htsc=氨基硫脲配体)和经式异构体[Co(Htsc)_3]Cl_3·4H_2O(C2).我们将几何异构体C1和C2作为水还原分子催化剂,与有机光敏剂荧光素一起构筑了不含贵金属成分的光催化分解水产氢体系.在三乙胺作为牺牲剂及纯水环境中,体系展现出了良好的光催化制氢性能.可见光照15 h后,体系产氢相对于催化剂的TON接近900.对比实验结果表明,具有这对几何异构的C1和C2具有相似的光催化产氢性能,暗示其催化机理的相似性.汞中毒实验结果表明,光催化分解水产氢过程中并没有钴纳米胶体形成,可以确定这是一个均相光催化分解水产氢体系.在纯水环境下,我们将C1和C2与传统的钴配合物(钴肟配合物:[Co(dmgH)_2pyCl](dmg H=丁二酮肟,py=吡啶);联吡啶钴配合物:[Co(bpy)_3Cl_2](bpy=2,2'-联吡啶))的催化活性进行对比.结果表明,催化剂C1和C2展现出了较强的光催化产氢活性.此外,电催化实验表明,在乙腈中且乙酸作为质子源的条件下,C1和C2具有相同的电催化活性,过电位接近640毫伏,催化转化频率(TOF)为每秒210.同时,在pH=7的磷酸盐缓冲溶液中,C1和C2也同样表现出对水分子的电催化产氢性能,过电势为560毫伏.这是当前第一例具有几何异构体的分子催化剂对光、电催化产氢体系影响的工作.

Microbial transformation for Region-selective Hydroxylation of Z-Butylidenephthalide by Aspergillus niger CGMCC 3.739

Microbial transformation is a useful tool for structure modification of active natural products.Z-Butylidenephthalide is the main active constituent of Angelica sinensis.In the present work,a pair of new oxidized metabolites,namely(-)(11R)-(Z)-11-hydroxy-butylidenephthalide(1a)and(+)(11S)-(Z)-11-hydroxy-butylidenephthalide(1b),were obtained from microbial transformation for region-selective 11-hydroxylation of Z-butylidenephthalide by Aspergillus niger CGMCC 3.739.Their structures,including absolute configurations,were elucidated by extensive analysis of HR-ESI-MS,NMR spectra,and the modified Mosher’s method.This is the first study on the microbial transformation of Z-butylidenephthalide,and these findings offer a tool for region-selective 11-hydroxylation of Z-butylidenephthalide.

CEOs’Diverse Career Experiences and the Effectiveness of Compensation Contracts:Evidence from Compensation Stickiness

CEO compensation stickiness represents an important indicator to measure the effectiveness of compensation contracts.This study uses CEO career experience data and compensation stickiness data from Shanghai and Shenzhen A-share listed companies from 2015 to 2020 to investigate the compensation contracts’effectiveness of CEOs with diverse career experiences.The findings are as follows:1)Compensation stickiness is more pronounced for CEOs with diverse career experiences.According to the mechanism test,these CEOs with diverse career experiences can obtain compensation incentives by reducing corporate uncertainty perception and improving total factor productivity.This approach leads to increased compensation stickiness and the effectiveness of compensation contracts.CEOs with diverse career experiences may receive excess compensation by raising agency costs,which intensifies compensation stickiness and weakens the effectiveness of compensation contracts.2)Compensation stickiness of CEOs with diverse career experiences is more significant in companies with lower investor protection,which brings about less effective compensation contracts.In contrast,in companies with higher diversification,the compensation stickiness of CEOs with diverse career experiences is more significant,which delivers more effective compensation contracts.The conclusions deepen the research of CEO compensation contracts and provide a helpful reference for CEO compensation management practices.

In utero delivery of mRNA to the heart,diaphragm and muscle with lipid nanoparticles

Nanoparticle-based drug delivery systems have the potential to revolutionize medicine,but their low vascular permeability and rapid clearance by phagocytic cells have limited their medical impact.Nanoparticles delivered at the in utero stage can overcome these key limitations due to the high rate of angiogenesis and cell division in fetal tissue and the under-developed immune system.However,very little is known about nanoparticle drug delivery at the fetal stage of development.In this report,using Ai9 CRE reporter mice,we demonstrate that lipid nanoparticle(LNP)mRNA complexes can deliver mRNA in utero,and can access and transfect major organs,such as the heart,the liver,kidneys,lungs and the gastrointestinal tract with remarkable efficiency and low toxicity.In addition,at 4 weeks after birth,we demonstrate that 50.99±5.05%,36.62±3.42%and 23.7±3.21%of myofiber in the diaphragm,heart and skeletal muscle,respectively,were transfected.Finally,we show here that Cas9 mRNA and sgRNA complexed to LNPs were able to edit the fetal organs in utero.These experiments demonstrate the possibility of non-viral delivery of mRNA to organs outside of the liver in utero,which provides a promising strategy for treating a wide variety of devastating diseases before birth.

Fluid-structure interaction simulation of pathological mitral valve dynamics in a coupled mitral valve-left ventricle model

Background Understanding the interaction between the mitral valve(MV)and the left ventricle(LV)is very important in assessing cardiac pump function,especially when the MV is dysfunctional.Such dysfunction is a major medical problem owing to the essential role of the MV in cardiac pump function.Computational modelling can provide new approaches to gain insight into the functions of the MV and LV.Methods In this study,a previously developed LV-MV model was used to study cardiac dynamics of MV leaflets under normal and pathological conditions,including hypertrophic cardiomyopathy(HOCM)and calcification of the valve.The coupled LV-MV model was implemented using a hybrid immersed boundary/finite element method to enable assessment of MV haemodynamic performance.Constitutive parameters of the HOCM and calcified valves were inversely determined from published experimental data.The LV compensation mechanism was further studied in the case of the calcified MV.Results Our results showed that MV dynamics and LV pump function could be greatly affected by MV pathology.For example,the HOCM case showed bulged MV leaflets at the systole owing to low stiffness,and the calcified MV was associated with impaired diastolic filling and much-reduced stroke volume.We further demonstrated that either increasing the LV filling pressure or increasing myocardial contractility could enable a calcified valve to achieve near-normal pump function.Conclusion The modelling approach developed in this study may deepen our understanding of the interactions between the MV and the LV and help in risk stratification of heart valve disease and in silico treatment planning by exploring intrinsic compensation mechanisms.

Functional characterization of disease/comorbidity-associated IncRNA

Background:Functional characterization of the long noncoding RNAs(IncRNAs)in disease attracts great attention,which results in a limited number of experimentally characterized IncRNAs.The major problems underlying the lack of experimental verifications are considered to come from the significant false-positive assignments and extensive genetic-heterogeneity of disease.These problems are even worse when it comes to the functional characterization in comorbidity(simultaneous/sequential presence of multiple diseases in a patient,and showing much wider prevalence,poorer treatment-response and longer illness-course than a single disease).Methods:Herein,FCCLnc was developed to characterize IncRNA function by(1)integrating diverse SNPs that were associated with 193 diseases standardized by International Classification of Diseases(ICD-11),(2)condition-specific expression of IncRNAs,(3)weighted correlation network of IncRNAs and protein-coding neighboring genes.Results:FCCLnc can characterize IncRNA function in both disease and comorbidity by not only controlling false discovery but also tolerating their disease heterogeneity.Moreover,FCCLnc can provide interactive visualization and full download of IncRNA-centered co-expression network.Conclusion:In summary,FCCLnc is unique in characterizing IncRNA function in diverse diseases and comorbidities and is highly expected to emerge to be an indispensable complement to other available tools.FCCLnc is accessible at https://idrblab.org/fcclnc/.