Homogenous coating of Li^(+)conductive Li_(5)AlO_(4)on single-crystalline nonstoichiometric Li_(1.04)Ni_(0.92)Al_(0.04)O_(2)for rechargeable lithium-ion batteries

Cobalt-free,nickel-rich LiNi_(1-x)Al_(x)O_(2)(x≤0.1)is an attractive cathode material because of high energy density and low cost but suffers from severe structural degradation and poor rate performance.In this study,we propose a molten salt-assisted synthesis in combination with a Li-refeeding induced aluminum segregation strategy to prepare Li_(5)AlO_(4)-coated single-crystalline slightly Li-rich Li_(1.04)Ni_(0.92)Al_(0.04)O_(2).The symbiotic formation of Li_(5)AlO_(4)from reaction between molten lithium hydroxide and doped aluminum in the bulk ensures a high lattice matching between the Ni-rich oxide and the homogenous conductive Li_(5)AlO_(4)that permits high Li^(+)conductivity.Benefiting from mitigated undesirable side reactions and phase evolution,the Li_(5)AlO_(4)-coated single-crystalline Li_(1.04)Ni_(0.92)Al_(0.04)O_(2)delivers a high specific capacity of220.2 mA h g^(-1)at 0.1 C and considerable rate capability(182.5 mA h g^(-1)at 10 C).Besides,superior capacity retention of 90.8%is obtained at 1/3 C after 100 cycles in a 498.1 mA h pouch full cell.Furthermore,the particulate morphology of Li_(1.04)Ni_(0.92)Al_(0.04)O_(2)remains intact after cycling at a cutoff voltage of 4.3 V,whereas slightly Li-deficient Li_(0.98)Ni_(0.97)Al_(0.05)O_(2)features intragranular cracks and irreversible lattice distortion.The results highlight the value of molten salt-assisted synthesis and Li-refeeding induced elemental segregation strategy to upgrade Ni-based layered oxide cathode materials for advanced Li-ion batteries.

中国细胞重编程和多能干细胞研究进展

近几十年是干细胞领域飞速发展的重要时期。随着中国经济实力的发展壮大,科研实力也在稳步增强,干细胞研究领域达到了国际并跑甚至领跑的水平。本文从体细胞核移植、诱导多能干细胞、单倍体多能干细胞和胚胎早期发育研究4个方面,对中国细胞重编程和干细胞领域的研究进展进行了历史性回顾,总结了中国科学家在相关领域所取得的重要科研成果。随着单细胞测序技术的发展,各种发育过程将实现更为深入的解读,干细胞的临床应用在中国也会大放异彩。

Novel confinement combustion method of nanosized WC/C for efficient electrocatalytic oxygen reduction

Nanosized tungsten carbide(WC)/carbon(C)catalyst was synthesized via a novel ultra-rapid confinement combustion synthesis method.The amount of activated carbon(AC)plays an important role in the morphology and structure,controlling both the precursor and final powder.The WC particles synthesized inside the pores of the AC had been 10-20 nm because of the confinement of the pore structure and the large specific surface area of AC.When used for oxygen reduction performance,the half-wave potential was−0.24 V,and the electron transfer number was 3.45,indicating the main reaction process was the transfer of four electrons.The detailed electrocatalytic performance and underlying mechanism were investigated in this work.Our study provides a novel approach for the design of catalysts with new compositions and new structures,which are significant for promoting the commercialization of fuel cells.

个人、经历和环境因素如何影响英语教师的评估观——一项叙事研究

已有研究表明教师的评估观受其个人特征、经历和特定的社会文化背景影响,但这些因素如何影响教师的评估观尚未得到充分研究。本研究基于48名中国高中英语教师的叙述框架数据,探究教师评估观及其影响因素。结果显示,教师普遍认同以促学为导向的评估目的;一系列因素对教师的评估观产生了不同程度的影响,包括个人因素(教师的主观能动性)、经历因素(教师对评估的[反]学徒式观察)以及环境因素(应试文化)。本文进而讨论了教师如何在促学导向的评估目的和问责导向的评估目的之间进行磋商与妥协,以及教师主观能动性、作为被评估者的情感体验和应试文化如何塑造教师评估观。研究对教师评估观研究以及教师评估素养政策、实践和专业发展具有重要启示。

The governance of imported 2019-nCov infections:What can be learned from China’s experience?

Delta and Omicron variants of 2019-nCoV are still spreading globally,and many imported infections have been identified in China as well.In order to control the spread chain from imported to local,China has implemented the dynamic Covid-zero policy.In this article we summarized China’s governance models and practices of fighting potential imported infections in two directions.One targets at international travelers,which can be outlined as four lines of defense:customs epidemic prevention,quarantine upon arrival,relevant laws and regulations,and community tracking.The other is against other vectors potentially carrying 2019-nCoV,which can be outlined by three lines of defense:customs epidemic prevention,disinfection and personal protection,and information management.However,there are still some challenges that are yet to be addressed,such as illegal immigration,accidental occupational exposure to 2019-nCoV,etc.China’s experience indicates that no country can stay safe during the global pandemic as long as there are local outbreaks in other countries,and active prevention and control measures based on science and a complete set of laws and regulations are still necessary at current stage.What’s more,accountable government commitment and leadership,strengthened health and social governance systems,and whole society participation are required.It is suggested that the global community continue to closely cooperate together and take active rather than passive actions to block the potential imported 2019-nCoV from causing local spreading.

急性共同性内斜视患者的立体视觉功能及相关因素分析

目的:分析急性共同性内斜视(AACE)患者的立体视觉功能及相关危险因素。方法:系列病例研究。连续收集2022年1月至2023年3月于北京同仁医院斜视与小儿眼科确诊的AACE患者共127例。收集患者的临床资料包括病史、屈光度、斜视度、双眼视觉功能(双眼同时视功能、融合功能、远立体视觉功能、近立体视觉功能、动态立体视觉功能)等眼部情况。采用Wilcoxon秩和检验比较看远和看近斜视度,Logistic回归模型分析远立体视、动态立体视觉功能的相关危险因素,线性回归模型分析近立体视觉功能的相关危险因素。结果:127例AACE患者中,正视6例,远视14例,近视107例。初次发病年龄4~57(22.2±12.4)岁,每日近距离用眼时间为2~16(8.3±3.0)h。看远斜视度为+30^(△)(+19^(△),+45^(△)),看近斜视度为+25^(△)(+15^(△),+45^(△)),看远斜视度大于看近斜视度,差异有统计学意义(Z=-3.17,P=0.002)。所有患者中存在同时视功能126例,存在融合功能116例,存在远立体视觉功能71例。近立体视觉功能方面,存在中心立体视17例,周边立体视42例,立体视盲68例。动态立体视觉功能方面,33例低速通过,26例高速通过,68例高速不通过。发病年龄早、眼位偏斜角度大是远立体视觉功能[OR=1.05,95%可信区间(CI):1.01-1.10,P=0.024;OR=0.96,95%CI:0.93-0.98,P<0.001]、近立体视觉功能(β=-0.16,t=-2.00,P=0.048;β=0.51,t=6.29,P<0.001)和动态立体视觉功能(OR=1.05,95%CI:1.00-1.09,P=0.032;OR=0.95,95%CI:0.92-0.98,P<0.001)损伤的危险因素。结论:AACE患者立体视觉功能存在不同程度的损伤,发病年龄早和斜视角度大是立体视觉功能损伤的重要危险因素。

Effect of SARS-CoV-2 infection in early pregnancy on placental development

Dear Editor,Since the COVID-19 pandemic, the potential risks associated with maternal SARS-CoV-2 infection and its effect on fetal development have been a subject of considerable public concern. Previous studies have shown that SARS-CoV-2 infection during pregnancy may increase the incidence of adverse outcomes.

基于分层安全控制结构的导弹装备任务安全性动态评价方法

长期贮存的多任务环境与复杂工况,对导弹装备的风险有效抑制与安全性准确评价提出了严格的要求。然而,导弹装备是典型的人-机-环耦合复杂系统,传统的安全性分析与评价方法无法满足其动态变化与准确量化的需求。为此,提出基于分层安全控制结构的导弹装备安全性动态评价方法,实现长期贮存任务情境下安全性的准确评价。首先,针对导弹装备的任务剖面特点,构建过程、任务、功能、信息和组织的多视图体系模型,实现任务过程与资源的准确描述。其次,构建分层安全控制结构模型,明确任务的事故致因因素与事故链。同时,针对导弹装备任务特点,构建面向长期贮存复杂多变环境下的人因绩效评价体系,实现人-机-环耦合条件下人因失误率的准确评价。然后,提出了一种融合STAMP和CREAM的安全动态反馈评价方法,以仿真的形式获得导弹任务的事故率。最后,对导弹测试任务进行案例分析,所提方法在人-机-环耦合情境下明确协调、控制和反馈共3类6个典型事故链,同时事故率精度提升70.08%,验证了所提方法的有效性与优越性。

Loss of Tet hydroxymethylase activity causes mouse embryonic stem cell differentiation bias and developmental defects

The TET family is well known for active DNA demethylation and plays important roles in regulating transcription,the epigenome and development.Nevertheless,previous studies using knockdown(KD)or knockout(KO)models to investigate the function of TET have faced challenges in distinguishing its enzymatic and nonenzymatic roles,as well as compensatory effects among TET family members,which has made the understanding of the enzymatic role of TET not accurate enough.To solve this problem,we successfully generated mice catalytically inactive for specific Tet members(Tetm/m).We observed that,compared with the reported KO mice,mutant mice exhibited distinct developmental defects,including growth retardation,sex imbalance,infertility,and perinatal lethality.Notably,Tetm/mmouse embryonic stem cells(mESCs)were successfully established but entered an impaired developmental program,demonstrating extended pluripotency and defects in ectodermal differentiation caused by abnormal DNA methylation.Intriguingly,Tet3,traditionally considered less critical for m ESCs due to its lower expression level,had a significant impact on the global hydroxymethylation,gene expression,and differentiation potential of mESCs.Notably,there were common regulatory regions between Tet1 and Tet3 in pluripotency regulation.In summary,our study provides a more accurate reference for the functional mechanism of Tet hydroxymethylase activity in mouse development and ESC pluripotency regulation.

PDGFR in PDGF-BB/PDGFR Signaling Pathway Does Orchestrates Osteogenesis ina Temporal Manner

Platelet-derived growth factor-BB(PDGF-BB)/platelet-derived growth factor receptor-β(PDGFR-β)pathway is conventionally considered as an important pathway to promote osteogenesis;however,recent study suggested its role during osteogenesis to be controversial.Regarding the differential functions of this pathway during 3 stages of bone healing,we hypothesized that temporal inhibition of PDGF-BB/PDGFR-βpathway could shift the proliferation/differentiation balance of skeletal stem and progenitor cells,toward osteogenic lineage,which leads to improved bone regeneration.We first validated that inhibition of PDGFR-βat late stage of osteogenic induction effectively enhanced differentiation toward osteoblasts.This effect was also replicated invivo by showing accelerated bone formation when block PDGFR-βpathway at late stage of critical bone defect healing mediated using biomaterials.Further,we found that such PDGFR-βinhibitor-initiated bone healing was also effective in the absence of scaffold implantation when administrated intraperitoneally.Mechanistically,timely inhibition of PDGFR-βblocked extracellular regulated protein kinase 1/2 pathway,which shift proliferation/differentiation balance of skeletal stem and progenitor cell to osteogenic lineage by upregulating osteogenesis-related products of Smad to induce osteogenesis.This study offered updated understanding of the use of PDGFR-βpathway and provides new insight routes of action and novel therapeutic methods in the field of bone repair.

Novel injectable composite incorporating denosumab promotes bone regeneration via bone homeostasis regulation

Repair of large bone defects remains to be clinically challenging,yet current bone repair strategies focus on optimizing the osteogenic capacity of bone grafts,while the role of osteoclasts in bone regeneration has been largely ignored.Herein,we designed a injectable self-curing bone grafting paste capable of regulating both an-abolic/catabolic activities during bone healing by immobilizing the RANKL inhibitor denosumab on dermal-derived extracellular matrix(ECM)microfibres,which were then incorporated into an injectable paste via a hydration reaction between𝛽-tricalcium phosphate(𝛽-TCP),monocalcium phosphate monohydrate(MCPM)and calcium sulfate hemihydrate(CSH).The incorporation of ECM microfibres not only serves as a sustained-release denosumab carrier to inhibit osteoclastogenesis but also improves the mechanical properties of the resulting com-posite by increasing the interaction between the organic and inorganic phases.In vitro,calcium supply from the composite along with ECM enhanced osteogenic differentiation of BMSC while release of denosumab effectively inhibits osteoclast fusion and alleviate osteoclastic activity.In vivo,it was observed that CSH/CP@ECM-Deno significantly reduced the number of osteoclasts,slowed down the process of bone resorption,and accelerated collagen deposition to promote new bone generation.These results suggest that modulation of osteoclastogenesis by interfering with bone homeostasis may be an effective bone repair strategy.

Occurrence and distribution of antibiotic resistance genes in the sediments of the East China Sea bays

The coastal area of the East China Sea has experienced rapid urbanization and industrialization in China since 1980 s, resulting in severe pollution of its environments.Antibiotic resistance genes(ARGs) are regarded as a kind of emerging pollutant with potential high risk. The sediment samples were collected from Hangzhou Bay(HB),Xiangshan Bay(XB), and Taizhou Bay(TB) to investigate the spatial occurrence and distribution of 27 ARGs and class I integron–integrase gene(intI1) in the coastal area of the East China Sea. The PCR results showed the frequent presence of 11 ARGs and intI1 in the sediments of the three bays. The qPCR results further showed that sulfonamide resistance was the most prevalent ARG type and antibiotic target replacement and protection were the most important resistance mechanisms in the sediments. Regarding the subtype of ARGs, sulI, tetW, and dfrA13 were the most abundant ARGs, in which sulI was higher in TB(based on both the absolute and relative abundances) and dfrA13 was higher in HB(based on the relative abundances). The network analysis revealed that intI1 had significant correlations with tetC, sulI, sulII, and blaPSE-1. Oil was the key connected factor, which had positive connections with sulI, sulII, and blaPSE-1. In addition, the joint effect of heavy metals and nutrients & organic pollutants might be crucial for the fate of ARGs in the coastal sediments.

Nuclear m^(6)A reader YTHDC1 regulates the scaffold function of LINE1 RNA in mouse ESCs and early embryos

N^(6)-methyladenosine(m^(6)A)on chromosome-associated regulatory RNAs(carRNAs),including repeat RNAs,plays important roles in tuning the chromatin state and transcription,but the intrinsic mechanism remains unclear.Here,we report that YTHDC1 plays indispensable roles in the self-renewal and differentiation potency of mouse embryonic stem cells(ESCs),which highly depends on the m^(6)A-binding ability.Ythdcl is required for sufficient rRNA synthesis and repression of the 2-cell(2C)transcriptional program in ESCs,which recapitulates the transcriptome regulation by the LINE1 scaffold.Detailed analyses revealed that YTHDC1 recognizes m^(6)A on LINE1 RNAs in the nucleus and regulates the formation of the LINE1-NCL partnership and the chromatin recruitment of KAP1.Moreover,the establishment of H3K9me3 on 2C-related retrotrans-posons is interrupted in Ythdcl-depleted ESCs and inner cell mass(ICM)cells,which consequently increases the transcriptional activities.Our study reveals a role of m^(6)A in regulating the RNA scaffold,providing a new model for the RNA-chromatin cross-talk.

One-step synthesis of thermally stable artificial multienzyme cascade system for efficient enzymatic electrochemical detection

Recently,metal-organic framework(MOF)-based multienzyme systems integrating different functional natural enzymes and/or nanomaterial-basedartificial enzymes are attracting increasing attention due to their high catalytic efficiency and promising application in sensing.Simpleand controllable integration of enzymes or nanozymes within MOFs is crucial for achieving efficient cascade catalysis and high stability.Here,we report a facile electrochemical assisted biomimetic mineralization strategy to prepare an artificial multienzyme system for efficient electrochemicaldetection of biomolecules.By using the G0x@Cu-MOF/copper foam(G0x@Cu-MOF/CF)architecture as a proof of concept,efficientenzyme immobilization and cascade catalysis were achieved by in situ encapsulation of glucose oxidase(GOx)within MOFs layer grown onthree-dimensional(3D)porous conducting CF via a facile one-step electrochemical assisted biomimetic mineralization strategy.Due to thebio-electrocatalytic cascade reaction mechanism,this well-designed GOx@Cu-MOF modified electrode exhibited superior catalytic activityand thermal stability for glucose sensing.Notably,the activity of GOx@Cu-MOF/CF still remained at ca.80%after being incubated at 80℃.In sharp contrast,the activity of the unprotected electrode was reduced to the original 10%after the same treatment.The design strategypresented here may be useful in fabricating highly stable enzyme@MOF composites applied for efficient photothermal therapy and otherplatform under high temperature.

Improved in situ sequencing for high-resolution targeted spatial transcriptomic analysis in tissue sections

Spatial transcriptomics enables the study of localization-indexed gene expression activity in tissues,providing the transcriptional landscape that in turn indicates the potential regulatory networks of gene expression.In situ sequencing(ISS)is a targeted spatial transcriptomic technique,based on padlock probe and rolling circle amplification combined with next-generation sequencing chemistry,for highly multiplexed in situ gene expression profiling.Here,we present improved in situ sequencing(IISS)that exploits a new probing and barcoding approach,combined with advanced image analysis pipelines for high-resolution targeted spatial gene expression profiling.We develop an improved combinatorial probe anchor ligation chemistry using a 2-base encoding strategy for barcode interrogation.The new encoding strategy results in higher signal intensity as well as improved specificity for in situ sequencing,while maintaining a streamlined analysis pipeline for targeted spatial transcriptomics.We show that IISS can be applied to both fresh frozen tissue and formalin-fixed paraffin-embedded tissue sections for single-cell level spatial gene expression analysis,based on which the developmental trajectory and cell-cell communication networks can also be constructed.

BMP4 preserves the developmental potential of mESCs through Ube2s-and Chmp4b-mediated chromosomal stability safeguarding

Chemically defined medium is widely used for culturing mouse embryonic stem cells(mESCs),in which N2B27 works as a substitution for serum,and GSK3βand MEK inhibitors(2i)help to promote ground-state pluripo-tency.However,recent studies suggested that MEKi might cause irreversible defects that compromise the developmental potential of mESCs.Here,we demon-strated the deficient bone morphogenetic protein(BMP)signal in the chemically defined condition is one of the main causes for the impaired pluripotency.Mechanisti-cally,activating the BMP signal pathway by BMP4 could safeguard the chromosomal integrity and proliferation capacity of mESCs through regulating downstream tar-gets Ube2s and Chmp4b.More importantly,BMP4 pro-motes a distinct in vivo developmental potential and a long-term pluripotency preservation.Besides,the pluripotent improvements driven by BMP4 are superior to those by attenuating MEK suppression.Taken together,our study shows appropriate activation of BMP signal is essential for regulating functional pluripotency and reveals that BMP4 should be applied in the serum-free culture system.

Esrrb plays important roles in maintaining self-renewal of trophoblast stem cells (TSCs) and reprogramming somatic cells to induced TSCs

Trophoblast stem cells (TSCs), which can be derived from the trophoectoderm of a blastocyst, have the ability to sustain self-renewal and differentiate into various placental trophoblast cell types. Meanwhile, essential insights into the molecular mechanisms controlling the placental development can be gained by using TSCs as the cell model. Esrrb is a transcription factor that has been shown to play pivotal roles in both embryonic stem cell (ESC) and TSC, but the precise mechanism whereby Esrrb regulates TSC-specific transcriptome during differentiation and reprogramming is still largely unknown. In the present study, we elucidate the function of Esrrb in self-renewal and differentiation of TSCs, as well as during the induced TSC (iTSC) reprogramming. We demonstrate that the precise level of Esrrb is critical for stem state maintenance and further trophoblast differentiation of TSCs, as ectopically expressed Esrrb can partially block the rapid differentiation of TSCs in the absence of fibroblast growth factor 4. However, Esrrb depletion results in downregulation of certain key TSC-specific transcription factors, consequently causing a rapid differentiation of TSCs and these Esrrb-deficient TSCs lose the ability of hemorrhagic lesion formation in vivo. This function of Esrrb is exerted by directly binding and activating a core set of TSC-specific target genes including Cdx2, Eomes, Sox2, Fgfr4, and Bmp4. Furthermore, we show that Esrrb overexpression can facilitate the MEF-to-iTSC conversion. Moreover, Esrrb can substitute for Eomes to generate GEsTM-iTSCs. Thus, our findings provide a better understanding of the molecular mechanism of Esrrb in maintaining TSC self-renewal and during iTSC reprogramming.

Enhancement of Xrcc1-mediated base excision repair improves the genetic stability and pluripotency of iPSCs

诱导多能干细胞(iPSC)因其强大的自我更新和分化能力而具有广阔的应用前景.然而,多个研究表明体细胞诱导重编程过程会引入数以千计的遗传畸变,进而带来临床应用的安全性问题,已有前期研究证明单核苷酸变异(SNVs)的逐渐积累会致使iPSC丧失发育潜能,但致使SNVs产生并积累的原因还尚未探明.本研究通过对不同DNA损伤修复通路的筛选验证后,发现重编程过程早中期碱基切除修复(BER)效率的不足是导致SNVs积累的重要原因,进一步的研究发现XRCC1可以显著增强重编程前中期的BER,从而降低引入的SNVs,提高iPSC基因组的稳定性.同时,XRCC1介导的BER增强也提高了体细胞诱导重编程的效率.更为重要的是,体内嵌合体实验证实高效的BER可以显著提高iPSC的质量.综上,该研究可以有效提高iPSC基因组的稳定性和多能性,为其临床应用的安全性提供了新思路.

Bilineage embryo-like structure from EPS cells can produce live mice with tetraploid trophectoderm

Self-organized blastoids from extended pluripotent stem(EPs)cells possess enormous potential for investigating postimplantation embryo development and related diseases.However,the limited ability of postimplantation development of Eps-blastoids hinders its further application.In this study,single-cell transcriptomic analysis indicated that the“trophectoderm(TE)-like structure”of EPSblastoids was primarily composed of primitive endoderm(PrE)-related cells instead of TE-related cells.We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure.Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation.Furthermore,we demonstrated that blastocyst-like structures reconstituted by combining the EPs-derived bilineage embryo-like structure(BLEs)with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses.In summary,our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.

Influence of earthquake input angle on seismic response of curved girder bridge

The maximum seismic response of curved bridge is significantly related to the input angle of designated earthquake. Owing to structure irregularities, bridge reactions result from the interaction between the moment and torsion forces. Based on the solving of the seismic response of structure excited by a one-way earthquake input, a uniform expression of the unfavorable angle of the earthquake input was derived, and the corresponding maximum response of structure was determined. Considering the orthotropic and skewed dual- directional earthquake input manners, the most unfavorable angles for the two cases were also derived, respectively. Furthermore, a series finite element models were built to analyze the multi-component seismic responses by examining an example of curved girder bridge considering the variation of curvature radius and the bearings arrangement. The seismic responses of the case bridges, were excited by earthquakes at different input angles, and were calculated and analyzed using a response spectrum method. The input angles of earthquake excitation were progressively increased. From the analysis and comparison based on the calculation results mentioned above, the most unfavorable angle of earthquake excitation corresponding to the maximum seismic response of the curved bridge could be determined. It was shown that the most unfavorable angles of earthquake input resulted from the different response combination methods were essentially coherent.