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China Foundry 2024年第2期21卷 168-174页

作者： Zhi-yong Zhang Jiao-jiao Cheng Jia-qi Xie shi-bing Liu kun shi Jun Zhao Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

关键词： titanium matrix composites microstucture microhardness tensile properties in-situ synthesis

Drug delivery systems for colorectal cancer chemotherapy

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Chinese Chemical Letters 2024年第2期35卷 163-175页

作者： Wen Chen kun shi Yan Yu Peipei Yang Zhongwu Bei Dong Mo Liping Yuan Meng Pan Yu Chen Zhiyong Qian Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengdu 610041China

Colorectal cancer causes the third most common type of malignant tumors with high morbidity and mortality.Chemotherapy is currently one of the most effective and common treatments for colorectal cancer.However,the poor water solubility of some chemotherapeutics,untargeted drug delivery,and the undesirable systemic side effects of conventional treatment remain the major issues for colorectal cancer chemotherapy.Fortunately,drug delivery systems(DDS)based on biomaterials have been widely investigated and found to be capable of resolving those issues with good performance.Therefore,the main goal of this review is to summarize and discuss the progress and potential advantages of different DDS for colorectal cancer chemotherapy.We not only reviewed the nanocarriers used to improve the solubility of chemotherapeutics,including liposomes,micelles,and nanoparticles,but also discussed targeted DDS based on specific ligand-receptor recognition and tumor microenvironmental stimulus responses.Furthermore,locally administered systems based on hydrogels and microspheres,which have been shown to increase drug accumulation at the tumor site while decreasing systemic toxicity,were also emphasized.DDS provides a good option for improving the efficacy of chemotherapy in the treatment of colorectal cancer.

关键词： Colorectal cancer Chemotherapy Drug delivery systems Solubility Targeted Local administration

An alfalfa MYB-like transcriptional factor MsMYBH positively regulates alfalfa seedling drought resistance and undergoes MsWAV3-mediated degradation

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Journal of Integrative Plant Biology 2024年第4期66卷 683-699页

作者： kun shi Jia Liu Huan Liang Hongbin Dong Jinli Zhang Yuanhong Wei Le Zhou Shaopeng Wang Jiahao Zhu Mingshu Cao Chris S.Jones Dongmei Ma Zan Wang College of Grassland Science and Technology China Agricultural UniversityBeijing 100193China Institute of Animal Sciences Chinese Academy of Agricultural SciencesBeijing 100193China AgResearch Grasslands Research Centre Palmerston North 4442New Zealand International Livestock Research Institute Nairobi 00100Kenya School of Ecology and Environment Ningxia UniversityYinchuan 750021China

Drought is a major threat to alfalfa(Medicago sativa L.)production.The discovery of important alfalfa genes regulating drought response will facilitate breeding for drought-resistant alfalfa cultivars.Here,we report a genome-wide association study of drought resistance in alfalfa.We identified and functionally characterized an MYB-like transcription factor gene(MsMYBH),which increases the drought resistance in alfalfa.Compared with the wild-types,the biomass and forage quality were enhanced in MsMYBH overexpressed plants.Combined RNA-seq,proteomics and chromatin immunoprecipitation analysis showed that MsMYBH can directly bind to the promoters of MsMCP1,MsMCP2,MsPRX1A and MsCARCAB to improve their expression.The outcomes of such interactions include better water balance,high photosynthetic efficiency and scavenge excess H_(2)O_(2)in response to drought.Furthermore,an E3 ubiquitin ligase(MsWAV3)was found to induce MsMYBH degradation under long-term drought,via the 26S proteasome pathway.Furthermore,variable-number tandem repeats in MsMYBH promoter were characterized among a collection of germplasms,and the variation is associated with promoter activity.Collectively,our findings shed light on the functions of MsMYBH and provide a pivotal gene that could be leveraged for breeding drought-resistant alfalfa.This discovery also offers new insights into the mechanisms of drought resistance in alfalfa.

关键词： alfalfa drought resistance E3 ubiquitin ligase MsMYBH MsWAV3 MYB-like transcriptional factor

The pikas of China: a review of current research priorities and challenges for conservation

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Integrative Zoology 2023年第1期18卷 110-128页

作者： Joseph P.LAMBERT Xiaozheng ZHANG kun shi Philip RIORDAN Wildlife Institute School of Nature ConservationBeijing Forestry UniversityBeijingChina Eco-Bridge Continental Haidian DistrictBeijingChina Marwell Wildlife WinchesterHampshireUK

Of the approximately 30 extant species of pika(Ochotona;Ochotonidae;Lagomorpha),at least 23 occur in China.Of these,8 are endemic,and 3 are classiﬁed as Endangered by the IUCN.Research into most Chinese species is scarce,and there is much to learn about basic aspects of their ecology.We reviewed the literature on the 23 Chinese Ochotona species,with the aim of highlighting knowledge gaps and biases in research allocation.Speciﬁcally,we identify(1)which pika species receive the most attention from researchers,(2)which topics are the most frequently studied,and(3)how well research satisﬁes conservation priorities.We covered a total of 879 articles,most of which were written in English or Chinese.Around 75%of all publications focused on the plateau pika Ochotona curzoniae.Seven species were represented by 10 or fewer publications each.Endangered and endemic species were particularly poorly represented.204 papers treated pikas as a pest,while 13 studied conservation issues.Nine species were considered possible targets for pest control,including some poorly known endemics.We make some recommendations on how research into Chinese Ochotona could be improved,including:(1)recognizing that the current species-level taxonomy may be an ineffective way to prioritize conservation research in Ochotona,(2)directing more research toward threatened and endemic species,subspecies,and populations,(3)researching the ecosystem engineering effects of pikas,(4)collecting basic data on natural history of the many understudied species,and(5)researching threats,including climate change and pest control campaigns.

关键词： conservation Lagomorpha Ochotona prioritization research allocation

Using genetic tools to inform conservation of fragmented populations of Asian elephants (Elephas maximus) across their range in China

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Integrative Zoology 2023年第3期18卷 453-468页

作者： Ying CHEN Yakuan SUN Mei HUA kun shi David DUDGEON School of Ecology and Nature Conservation Beijing Forestry UniversityBeijingChina School of Biological Sciences The University of Hong KongHong Kong SARChina Institute of Agro-food Technology Jilin Academy of Agricultural SciencesChangchunChina Eco-Bridge Continental BeijingChina

A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek,motivating the government to propose establishment of an Asian elephant national park.However,planning is hampered by a lack of genetic information on the remaining populations in China.We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure.We identiﬁed 237 unique genotypes(153 females,84 males),representing 81%of the known population.However,the effective population size was small(28,range 25–32).Historic demographic contraction appeared to account for low haplotype diversity(Hd=0.235),but mod-erate nucleotide and nuclear diversity(π=0.6%,He=0.55)was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar,Lao PDR,and Vietnam.The 5 populations fell into 3 clusters,with Nangunhe elephants differing consistently from the other 4 populations(FST=0.23);elephants from Mengyang,Simao,and Jiangcheng belonged to a single population(henceforth,MSJ),and differed from the Shangyong population(FST=0.11).Interpopulation genetic variation reﬂected isola-tion by distance and female-biased dispersal.Chinese elephants should be managed as 2 distinct units:Nangunhe and another combining Shangyong and MSJ;their long-term viability will require restoring geneﬂow between Shangyong and MSJ,and between elephants in China and neighboring countries.Our results have the potential to inform conservation planning for an iconic megafaunal species.

关键词： demography elephas maximus genetic diversity interpopulation variation national park

Catalytic asymmetric dearomative azo-Diels–Alder reaction of 2-vinlyindoles

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Chinese Chemical Letters 2024年第4期35卷 357-362页

作者： Yu-Hang Miao Zheng-Xu Zhang Xu-Yi Huang Yuan-Zhao Hua shi-kun Jia Xiao Xiao Min-Can Wang Li-Ping Xu Guang-Jian Mei Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450052China School of Chemistry and Chemical Engineering Shandong University of TechnologyZibo 255000China Institute of Pharmaceutical Science and Technology Zhejiang University of TechnologyHangzhou 310014China

Due to the high electrophilic nature of azo-dienophiles, azo-Diels–Alder proceeds rapidly even without the need of a catalyst and is therefore regarded as the “click reaction”. This spontaneity causes strong background reaction and poses a daunting challenge to chemists for developing the catalytic asymmetric version. Reported herein is the first catalytic asymmetric dearomative azo-Diels–Alder reaction between2-vinylindoles and triazoledione. This protocol makes use of the high energy barrier of dearomatization to avert the strong background reaction of azo-Diels–Alder reaction, allowing the implementation of the projected reaction at ambient temperature. Density functional theory calculations have been performed to gain insights into the reaction mechanism and the origins of the enantioselectivity. By using this method,a variety of tetracyclic indole derivatives have been readily prepared in good to excellent yields and with excellent diastereo-and enantio–selectivities(33 examples, up to 97% yield and >99% ee, >20:1 dr).

关键词： Catalytic asymmetric dearomatization Azo-Diels–Alder reaction 2-Vinylindoles Chiral phosphoric acid Tetracyclic indole derivatives

An injectable conductive hydrogel restores electrical transmission at myocardial infarct site to preserve cardiac function and enhance repair

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生物活性材料(英文) 2023年第2期20卷 339-354页

作者： Linghong Zhang Tao Li Yan Yu kun shi Zhongwu Bei Yongjun Qian Zhiyong Qian State Key Laboratory of Biotherapy State Key Laboratory and Collaborative Innovation Center of BiotherapyWest China HospitalSichuan UniversityChengdu610041SichuanPR China Department of Cardiovascular Surgery West China HospitalSichuan UniversityChengdu610041SichuanPR China

Myocardial infarction(MI)leads to massive cardiomyocyte death and deposition of collagen fibers.This fibrous tissue disrupts electrical signaling in the myocardium,leading to cardiac systolic and diastolic dysfunction,as well as arrhythmias.Conductive hydrogels are a promising therapeutic strategy for MI.Here,we prepared a highly water-soluble conductive material(GP)by grafting polypyrrole(PPy)onto non-conductive gelatin.This component was added to the gel system formed by the Schiff base reaction between oxidized xanthan gum(OXG)and gelatin to construct an injectable conductive hydrogel.The prepared self-healing OGGP3(3 wt%GP)hydrogel had good biocompatibility,elastic modulus,and electrical conductivity that matched the natural heart.The prepared biomaterials were injected into the rat myocardial scar tissue 2 days after MI.We found that the cardiac function of the rats treated with OGGP3 was improved,making it more difficult to induce arrhythmias.The electrical resistivity of myocardial fibrous tissue was reduced,and the conduction velocity of myocardial tissue was increased.Histological analysis showed reduced infarct size,increased left ventricular wall thickness,increased vessel density,and decreased inflammatory response in the infarcted area.Our findings clearly demonstrate that the OGGP3 hydrogel attenuates ventricular remodeling and inhibits infarct dilation,thus showing its potential for the treatment of MI.

关键词： Myocardial infarction Injectable hydrogel Conductivity Cardiac function

A novel Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy designed using cluster-plus-glue-atom model for laser additive manufacturing

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中国铸造:英文版 2023年第5期20卷 414-422页

作者： Tian-yu Liu Yan-chun Lou Shuang Zhang Zhi-hao Zhu Jun Zhao shi-bing Liu kun shi Ning Zhao National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina

A novel Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy was designed using the cluster formula approach(cluster-plus-glue-atom model)and prepared by laser melting deposition(LMD).Its composition formula 12[Al-Ti_(12)](AlTi_(2))+5[Al_(0.8)Si_(0.2)-Ti_(12)Zr_(2)](V_(0.8)Mo_(0.2)Nb_(1)Ti)features an enhancedβ-Ti via co-alloying of Zr,V,Mo,Nb and Si.The experimental results show that the cluster formula ofαandβphases in the novel alloy are respectivelyα-[Al-Ti_(11.5)Zr_(0.5)](Al_(1)Ti_(2))andβ-[Al_(0.8)Si_(0.2)-Ti_(13.2)Zr_(0.8)](V_(1)Mo_(0.4)Nb_(1.6)),both containing Zr elements.The fitted composition via the α andβphase cluster formulas has little difference with the actual alloy composition,suggesting that the validity of cluster-plus-glue-atom model in the alloy composition design.After hot isostatic pressing(HIP),both the Ti-6Al-4V and the novel alloy by LMD are characterized by prior-βcolumnar grains,while the typicaltexture disappears.Compared with Ti-6Al-4V,Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy exhibits a combination of higher strength(1,056 MPa)and higher ductility(14%)at room temperature and higher strength(580 MPa)at 550℃ after HIP,and can potentially serves as LMD materials.

关键词： additive manufacturing laser melting deposition novel titanium alloy composition design cluster-plus-glue-atom model

Anthropogenic pressures increase extinction risk of an isolated Asian elephant(Elephas maximus)population in southwestern China,as revealed by a combination of molecular-and landscape-scale approaches

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Integrative Zoology 2022年第6期17卷 1078-1094页

作者： Ying CHEN Yakuan SUN Luciano ATZENI Luke GIBSON Mei HUA Keyu LI kun shi David DUDGEON School of Ecology and Nature Conservation Beijing Forestry UniversityBeijingChina School of Biological Sciences The University of Hong KongHong KongChina Eco-Bridge Continental BeijingChina School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhenChina Institute of Special Animal and Plant Sciences of Chinese Academy of Agricultural Sciences ChangchunChina School of Earth Sciences Yunnan UniversityKunmingChina

Identiﬁcation of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019.A total of 22 unique genotypes were identiﬁed from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis,including 13 males and 9 females.Based on the size of fecal boli,1 animal was a juvenile,9 were subadults,and 12 were adults,indicating that recruitment was limited.The effective population size was small(15.3)but there was no signature of a recent population bottleneck.We observed a low genetic diversity(He=0.46±0.05)and a high level of inbreeding(Fis of 0.43±0.11),suggesting low population viability and high risk of extinction.In total,these elephants lost nearly two thirds(62%)of their habitat in 3 decades.The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population.We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km2 of suitable habitat available.This could allow a population increase of 14 elephants,possibly by translocating individuals from elsewhere in China.Ourﬁndings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.

关键词： fragmentation inbreeding isolation land-use change population viability

Corrosion and wear properties of in situ(TiB+TiC)/TA15 composites with a high volume percentage of reinforcement

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中国铸造:英文版 2023年第5期20卷 423-431页

作者： Wei-long Wang kun shi Jun Zhao shi-bing Liu Jiao-jiao Cheng Wei-chen Qiu Tian-yu Liu Zhi-yong Zhang Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

The in situ(TiC+TiB)/TA15 composites with different volume percentages of reinforcement(10%,15%,20%and 25%)were prepared by water-cooled copper crucible vacuum suspension melting technology.The structures and compositions of the TA15 alloy and its composites were analyzed by XRD and EDS,and their electrochemical corrosion behaviors in the 3.5%NaCl solution were studied.Corrosion wear testing was conducted using a reciprocating ball-on-disc wear tester under a 10 N load.Results show that the in situ fibrous TiB phase and the granular TiC phase are uniformly distributed on the composite matrix.The microhardness can reach up to 531 HV as 25vol.%TiC+TiB reinforcement is added.Compared with the TA15 alloy,the volume wear rate decreases from(2.21±0.07)×10^(-4)to(1.75±0.07)×10^(-4)mm^(3)·N^(-1)·m^(-1)by adding 15vol.%TiC+TiB reinforcement,and the wear mechanism is adhesive wear.When the volume percentage of the reinforcement phase reaches 25%,the volume wear rate increases from(1.75±0.07)×10^(-4)to(2.41±0.07)×10^(-4)mm^(3)·N^(-1)·m^(-1),and the wear mechanism changes into abrasive wear.The volume loss resulted by the interaction between corrosion and wear accounts for more than 27%of the total wear volume.The volume loss due to wear-induced corrosion changes from 1.94%to 4.06%with different additions of reinforcement.The volume loss caused by corrosion-induced wear initially increases from 24.08%to 26.90%as the reinforcement increases from 0 to 15%due to the increase of corrosion potential,and then decreases from 26.90%to 25.68%as the reinforcement increases from 15%to 25%due to the peeling of TiC phase.

关键词： titanium matrix composites high volume percentage corrosion wear wear mechanism