|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | PAQR10 and PAQR11 mediate Ras signaling in the Golgi apparatus显示文摘地岬在许多细胞的活动起一个枢轴的作用,并且它的 subcellular 区分提供空间、时间的选择。这里,我们报导由二高度相应的蛋白质 PAQR10 和孕激素和 AdipoQ 受体家庭的 PAQR11 在 Golgi 仪器发信号的地岬的空间规定的一个模式。PAQR10 和 PAQR11 在 Golgi 仪器是只局部性的。PAQR10/PAQR11 的 Overexpression 刺激基础、导致 EGF 的英皇家空军之阶级最低之兵 phosphorylation 并且以一种剂量依赖者方式增加英皇家空军之阶级最低之兵目标基因的表示。PAQR10/PAQR11 的 Overexpression 显著地提高 HRas, NRas 和 KRas4A 的 Golgi 本地化,然而并非 KRas4B。PAQR10 和 PAQR11 罐头也与 HRas, NRas 和 KRas4A 交往,然而并非 KRas4B。在由 PAQR10/PAQR11 的 overexpression 的 Golgi 仪器的增加的地岬蛋白质处于一个活跃状态。一致地, PAQR10 和 PAQR11 还原剂击倒在 Golgi 仪器的刺激 EGF 的英皇家空军之阶级最低之兵 phosphorylation 和地岬激活。有趣地, PAQR10 和 PAQR11 能与 RasGRP1,地岬的 guanine 核苷酸交换蛋白质,和 RasGRP1 的增加 Golgi 本地化交往。RasGRP1 的 C1 领域为和 PAQR10/PAQR11 的 RasGRP1 的相互作用必要、足够。由 overexpressed PAQR10/PAQR11 的英皇家空军之阶级最低之兵 phosphorylation 的模拟被 RasGRP1 的 downregulation 废除。而且, PC12 房间的区别被 PAQR10/PAQR11 的 overexpression 显著地提高。一起,这研究揭开由 PAQR10 和 PAQR11 在 Golgi 仪器发信号的地岬的空间规定的一个新范例。 | Ting Jin Qiurong Ding Heng Huang Daqian Xu Yuhui Jiang Ben Zhou Zhenghu Li Xiaomeng Jiang Jing He Weizhong Liu Yixuan Zhang Yi Pan Zhenzhen Wang Walter G Thomas Yan Chen | 2012 | Cell Research2012，22，4： | 6 |
| 2 | Construction of Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles with multiple hetero-interfaces for enhanced electromagnetic wave absorption显示文摘Nanocomposites with heterogeneous structures and magneto-electric synergistic losses have broad prospects for improving electromagnetic wave(EMW)absorption performance.In this study,we synthesized Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles with abundant hetero-interfaces and multiple magnetoelectric loss mechanisms by a facile hydrothermal method.The excess 0.5 oxygen atoms in MnCo_(2)O_(4.5) produce more vacancies and contribute to the enhancement of electrical conductivity.Sequential nanoneedle clusters facilitate multiple reflections and absorption of EMW in the materials,which are accompanied by an abundance of heterogeneous interfaces to improve the dielectric loss.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)composites showed a minimum reflection loss(RLmin)of30.01 dB and a superior effective absorption bandwidth(EAB)of 6.12 GHz(11.88 GHze18 GHz)at a thickness of 2.00 mm.Computer Simulation Technology(CST)revealed that the obtained particles show very low radar crosssection(RCS)values and almost full coverage angles.The maximum reduction of RCS at vertical incidence reaches 19.98 dB m2.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles exhibit outstanding radar attenuation properties,which can effectively inhibit the reflection and scattering of EMW.Therefore,the prepared Co_(2)NiO_(4)@MnCo_(2)O_(4.5)absorbers have great application potential in the field of EMW absorption. | Yi Zhang Shujuan Tan Zhuoting Zhou Xiaomeng Guan Yu Liao Chen Li Guangbin Ji | 2023 | Particuology2023，，10： | 5 |
| 3 | Novel application of bergapten and quercetin with anti-bacterial,osteogenesis-potentiating,and anti-inflammation tri-effects显示文摘The bacteria-mediated inflammatory conditions adversely affect the osseointegration process of endosseous implants,which can even lead to implant malfunction or failure.Local drug delivery has been designed to exert anti-inflammatory and antibacterial activities,but whether this strategy has an effect on the compromised osseointegration under inflammation has rarely been studied.The present study focused on the osteoinductive efficacy of two known phytoestrogens[bergapten(BP)and quercetin(QE)]on implant sites under multiple bacteria-infected conditions in situ.Furthermore,the gene expression profiles of rat bone mesenchymal stem cells(rBMSCs)treated with BP and QE in the presence of Porphyromonas gingivalis-derived lipopolysaccharide were identified.The results showed that both drugs,especially QE,had significant potentiating effects on promoting osteogenic differentiation of rBMSCs,resisting multiple pathogens,and reducing inflammatory activity.Meanwhile,RNA sequencing analysis highlighted the enriched gene ontology terms and the differentially expressed genes(Vps25,Il1r2,Csf3,Efemp1,and Ccl20)that might play essential roles in regulating the above tri-effects,which provided the basis for the drug delivery system to be used as a novel therapeutic strategy for integrating peri-implant health.Overall,our study confirmed that QE appeared to outperform BP in osteogenesis and bacterial killing but not in anti-inflammation.Moreover,both drugs possess favorable tri-effects and can serve as the pivotal agents for the drug delivery system to boost osseointegration at inflammatory implant sites. | Jianxu Wei Xiaomeng Zhang Yuan Li Xinxin Ding Yi Zhang Xue Jiang Hongchang Lai Junyu Shi | 2021 | Acta Biochimica et Biophysica Sinica2021，53，6： | 4 |
| 4 | Expert consensus on perioperative management of liver transplantation in adults with acute-on-chronic liver failure显示文摘Acute-on-chronic liver failure(ACLF)is a syndrome in which acute liver failure with extrahepatic organ failure occurs on chronic liver disease.Recently,liver transplantation is the only effective treatment for ACLF.There is still room for discussion on the optimal surgery timing for ACLF,perioperative infection prevention and control,and maintenance of nutrition and organ function.The Transplantation Immu-nology Committee of Branch of Organ Transplantation Physician of Chinese Medical Doctor Association and Enhanced Recovery of Liver Transplantation Group of Enhanced Recovery after Surgery Committee of Chinese Research Hospital Association invited relevant experts to discuss the perioperative management of ACLF liver transplantation in areas including surgery timing,organ protection,nutritional support,infection prevention and control,rehabilitation exercises,regulation of the internal environment,etc.An expert consensus was developed as reference for clinicians. | Transplantation Immunology Committee of Branch of Organ Transplantation Physician of Chinese Medical Doctor Association Enhanced Recovery of Liver Transplantation Group of Enhanced Recovery after Surgery Committee of Chinese Research Hospital Society Guihua Chen Yang Yang Huimin Yi Jianrong Liu Pinglan Lu Lijuan Li Mingming Fan Xiaomeng Yi Haijin Lv Xuxia Wei | 2021 | Liver Research2021，5，2： | 3 |
| 5 | Suppression of FHL2 Expression Induces Cell Differentiation and Inhibits Gastric and Colon Carcinogenesis显示文摘 | Jide Wang Yi Yang Harry H.X. Xia Qing Gu Marie C.M. Lin Bo Jiang Ying Peng Guoqing Li Xiaomeng An Yali Zhang Zehao Zhuang Zhenshu Zhang Hsiang Fu Kung Benjamin C.Y. Wong | 2007 | Gastroenterology2007，，3： | 1 |
| 6 | Artificial nanomotors: Fabrication, locomotion characterization, motion manipulation, and biomedical applications显示文摘Artificial nanomotors are nanoscale machines capable of converting surrounding other energy into mechanical motion and thus entering the tissues and cells of organisms.They hold great potential to revolutionize the diagnosis and treatment of diseases by actively targeting the lesion location,though there are many new challenges that arise with decreasing the size to nanoscale.This review sum-marizes and comments on the state-of-the-art artificial nanomotors with ad-vantages and limitations.It starts with the fabrication methods,including common physical vapor deposition and colloidal chemistry methods,followed by the locomotion characterization and motion manipulation.Then,the in vitro and in vivo biomedical applications are introduced in detail.The challenges and future prospects are discussed at the end. | Liangmeng Wang Xiaomeng Hao Zhixue Gao Zili Yang Yi Long Ming Luo Jianguo Guan | 2022 | Interdisciplinary Materials2022，1，2： | 1 |
| 7 | Mitochondrial temperature-responsive drug delivery reverses drug resistance in lung cancer显示文摘Reversal of cancer drug resistance remains a critical challenge in chemotherapy.Mitochondria-targeted drug delivery has been suggested to mitigate drug resistance in cancer.To overcome the intrinsic limitations in conventional mitochondrial targeting strategies,we develop mitochondrial temperature-responsive drug delivery to reverse doxorubicin(DOX)resistance in lung cancer.Results demonstrate that the thermoresponsive nanocarrier can prevent DOX efflux and facilitate DOX accumulation and mitochondrial targeting in DOX-resistant tumors.As a consequence,thermoresponsive nanocarrier enhances the cytotoxicity of DOX and reverses the drug resistance in tumor-bearing mice.This work represents the first example of mitochondrial temperature-responsive drug delivery for reversing cancer drug resistance. | Lifo Ruan Jun Chen Chuanchao Du Huiru Lu Jiayu Zhang Xiaomeng Cai Rui Dou Wenchu Lin Zhifang Chai Guangjun Nie Yi Hu | 2022 | Bioactive Materials2022，7，7： | 1 |
| 8 | Impact of Autumn SST in the Japan Sea on Winter Rainfall and Air Temperature in Northeast China显示文摘We studied the impact of sea surface temperature anomaly(SSTA) in the Japan Sea and the sea area east of Japan on the winter rainfall and air temperature in Northeast(NE) China using the singular value decomposition(SVD) and empirical orthogonal function(EOF). The monthly-mean rainfall data observed at 160 stations in China, monthly-mean sea surface temperature(SST) of the Hadley Center for Climate Prediction and Research and monthly-mean air temperature from the NCEP reanalysis during 1960–2011 were used. Correlation analysis indicates that the SSTAs in the Japan Sea in September may last for three or four months and are an important index for forecasting the winter rainfall and air temperature in NE China. Positive SSTAs in the central Japan Sea and in the sea area east of Tokyo correspond to positive rainfall anomaly and negative air temperature anomaly in NE China. With the rise of SST in the Japan Sea, a weak cyclone appears over the Japan Sea. The northeasterly wind transports water vapor from the Okhotsk to NE China, resulting in more rainfall and lower air temperature. Negative SSTA years are accompanied by warmer air temperature and less snow in NE China. The 1000 h Pa geopotential height anomaly and wind anomaly fields are simulated by IAP-9L model, which supports the analysis results. | SHI Xiaomeng SUN Jilin WU Dexing YI Li WEI Dongni | 2015 | Journal of Ocean University of China2015，14，4： | 1 |
| 9 | Schaftoside inhibits 3CL^(pro)and PL^(pro)of SARS-CoV-2 virus and regulates immune response and inflammation of host cells for the treatment of COVID-19显示文摘It is an urgent demand worldwide to control the coronavirus disease 2019(COVID-19)pandemic caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus.The 3-chymotrypsin-like protease(3CL^(pro))and papain-like protease(PL^(pro))are key targets to discover SARS-CoV-2 inhibitors.After screening 12 Chinese herbal medicines and 125 compounds from licorice,we found that a popular natural product schaftoside inhibited 3CL^(pro)and PL^(pro)with IC_(50)values of 1.73±0.22 and 3.91±0.19μmol/L,respectively,and inhibited SARS CoV-2 virus in Vero E6 cells with EC_(50)of 11.83±3. 23μmol/L. Hydrogen-deuterium exchange mass spectrometry analysis, quantum mechanics/molecular mechanics calculations, together with site-directed mutagenesis indicated the antiviral activities of schaftoside were related with non-covalent interactions with H41, G143 and R188 of3CLpro, and K157, E167 and A246 of PLpro. Moreover, proteomics analysis and cytokine assay revealed that schaftoside also regulated immune response and inflammation of the host cells. The antiinflammatory activities of schaftoside were confirmed on lipopolysaccharide-induced acute lung injury mice. Schaftoside showed good safety and pharmacokinetic property, and could be a promising drug candidate for the prevention and treatment of COVID-19. | Yang Yi Meng Zhang Heng Xue Rong Yu Yang-Oujie Bao Yi Kuang Yue Chai Wen Ma Jing Wang Xiaomeng Shi Wenzhe Li Wei Hong Junhua Li Elishiba Muturi Hongping Wei Joachim Wlodarz Szczepan Roszak Xue Qiao Hang Yang Min Ye | 2022 | Acta Pharmaceutica Sinica B2022，12，11： | 0 |
| 10 | Neighbouring carbonyl group-assisted sequential 1,2-azide and1,4-oxygen migrations of vinyl azides leading to α-azido ketones显示文摘The development of azide migration reactions is a formidable challenge due to potential competition from side processes driven by the release of molecular nitrogen. Here, we show a novel neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migration reaction of α-vinyl azides for the efficient preparation of a range of α-azido ketones. This represents the first transformation of α-vinyl azides into α-azido ketones. Notable features of this method are its high efficiency, broad substrate scope, excellent functional group compatibility, and high yields. The computational studies gave a key insights into the regioselective 1,2-azide and 1,4-oxygen migrations assisted by the neighbouring carbonyl group. Further conversions into a variety of nitrogen-containing compounds demonstrated the synthetic utility of the α-azido ketone products. Preliminary mechanistic studies disclosed a novel reaction mechanism involving neighbouring carbonyl group-assisted sequential 1,2-azide and1,4-oxygen migrations. | Yi Gai Yongquan Ning Paramasivam Sivaguru Xiaomeng Li Yue Zhao Jiayi Wu Xihe Bi | 2020 | Science China Chemistry2020，63，4： | 0 |
| 11 | Oxaliplatin plus irinotecan vs irinotecan as second-line treatment in pancreatic cancer patients:a randomized–controlled open-label Phase II study显示文摘Background:Limited second-line therapeutic options are available for metastasis pancreatic cancer(mPC).We aimed to explore the efficacy and safety of oxaliplatin plus irinotecan(IROX)in mPC patients.Methods:This is an open-label,Phase 2,randomized study of mPC patients(aged 18–75 years)who failed when using gemcitabine plus S-1 as first-line therapy.Block randomization with a block size of four was used to randomly assign patients(1:1)between October 2015 and December 2017 to receive either IROX(oxaliplatin 85mg/m2 and irinotecan 160mg/m2)or irinotecan monotherapy(irinotecan 180mg/m^(2))until disease progression,unacceptable adverse events,or consent withdrawal.The primary end point was overall survival,and the secondary end points were progression-free survival,overall response rate,and adverse event rate.Results:A total of 74 patients were enrolled in this study,including 44 males and 30 females,with an average age of 61 years.The median overall survival was 10.2 and 6.7 months(adjusted hazard ratio[HR],0.7;95%confidence interval[CI],0.4–1.2;P=0.20)and the median progression-free survival was 5.1 and 2.3 months(adjusted HR,0.4;95%CI,0.2–0.6;P<0.01)in the IROX group and irinotecan group,respectively.The overall response rates were 18.4%(7/38)in the IROX group and 5.5%(2/36)in the irinotecan group(P=0.06).Grade 3–4 adverse events occurred in 34%(13/38)of patients in the IROX group and 19%(7/36)of patients in the irinotecan group(P=0.15).Conclusions:IROX had no significant survival benefit over irinotecan monotherapy in our study.However,IROX reduced the risk of disease progression by 60%,with acceptable toxicity. | Hangyu Zhang Zhou Tong Lulu Liu Qihan Fu Xudong Zhu Xiaomeng Dai Xuanwen Bao Weijia Fang Yi Zheng Peng Zhao | 2023 | Gastroenterology Report2023，11，1： | 0 |
| 12 | An antibacterial mechanism of titanium alloy based on micro-area potential difference induced reactive oxygen species显示文摘Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal material is to incorporate toxic metal such as Cu and Ag.However,the reported Cu^(2+)or Ag~+released concentration from antibacterial alloys was much less than the reported minimum inhibitory ion concentrations(MIC),revealing the existence of an unknown alternative antimicrobial mechanism not relying on the toxicity of the metal ions.Herein,we proposed a new antibacterial mechanism that the antibacterial effectiveness of the different alloys is proportional to the micro-area potential differences(MAPDs)on the surface of the alloys.We designed three kinds of Ti-M(M=Zr,Ta and Au)alloys to eliminate the potential antibacterial contribution from Cu and Ag ion.We demonstrated that high MAPDs are associated with great production of reactive oxygen species(ROS),resulting in the killing effect to the biofilm known to be associated with implant infections(Staphlococcus aureus and Escherichia coli).These results provide new insights for the design of antibacterial alloys. | Shan Fu Yuan Zhang Yi Yang Xiaomeng Liu Xinxin Zhang Lei Yang Dake Xu Fuhui Wang Gaowu Qin Erlin Zhang | 2022 | Journal of Materials Science & Technology2022，，24： | 0 |
| 13 | Gas flow and filter ventilation of an unlit cigarette: model building,numerical solution and experimental validation显示文摘Understanding the fundamcntal relationship betwecn gas dilution rate of a cigarette and key cigarette design parameters is important in the overall control of smoke yield.In this work,an equation was derived to express the total gas dilution with the cigarette rod length,cigarette paper air permeability,and the filter ventilation level.The relationship was validated using experimental results.The accuracy of the developed model was dependent on the regression method used,i.e.,linear or a nonlinear.The expression provides a quantitative description of the interactions between filter ventilation level,cigarette length,cigarette circumference and cigarette paper air permeability and the total air dilution at the cigarette's mouth end. | WANG Le CUI Xiaomeng YOU Min YI Bin XIE Guoyong LU Duanfeng DENG Nan ZHANG Ke ZHANG Mingjian LI Bin WANG Bing | 2018 | 烟草科技2018，51，A01： | 0 |
| 14 | Performance Comparison of Computational Methods for the Prediction of the Function and Pathogenicity of Non-coding Variants显示文摘Non-coding variants in the human genome significantly influence human traits and complex diseases via their regulation and modification effects.Hence,an increasing number of computational methods are developed to predict the effects of variants in human non-coding sequences.However,it is difficult for inexperienced users to select appropriate computational methods from dozens of available methods.To solve this issue,we assessed 12 performance metrics of 24 methods on four independent non-coding variant benchmark datasets:(1)rare germline variants from clinical relevant sequence variants(ClinVar),(2)rare somatic variants from Catalogue Of Somatic Mutations In Cancer(COSMIC),(3)common regulatory variants from curated expression quantitative trait locus(eQTL)data,and(4)disease-associated common variants from curated genomewide association studies(GWAS).All 24 tested methods performed differently under various conditions,indicating varying strengths and weaknesses under different scenarios.Importantly,the performance of existing methods was acceptable for rare germline variants from ClinVar with the area under the receiver operating characteristic curve(AUROC)of 0.4481–0.8033 and poor for rare somatic variants from COSMIC(AUROC=0.4984–0.7131),common regulatory variants from curated eQTL data(AUROC=0.4837–0.6472),and disease-associated common variants from curated GWAS(AUROC=0.4766–0.5188).We also compared the prediction performance of 24 methods for non-coding de novo mutations in autism spectrum disorder,and found that the combined annotation-dependent depletion(CADD)and context-dependent tolerance score(CDTS)methods showed better performance.Summarily,we assessed the performance of 24 computational methods under diverse scenarios,providing preliminary advice for proper tool selection and guiding the development of new techniques in interpreting non-coding variants. | Zheng Wang Guihu Zhao Bin Li Zhenghuan Fang Qian Chen Xiaomeng Wang Tengfei Luo Yijing Wang Qiao Zhou Kuokuo Li Lu Xia Yi Zhang Xun Zhou Hongxu Pan Yuwen Zhao Yige Wang Lin Wang Jifeng Guo Beisha Tang Kun Xia Jinchen Li | 2023 | Genomics, Proteomics & Bioinformatics2023，21，3： | 0 |
| 15 | Association between GABRG2 rs211037 polymorphism and febrile seizures:a metaanalysis显示文摘Background:Emerging evidence has implied that the GABRG2 gene play a role in the mechanism of febrile seizure(FS),however,the relationship between GABRG2 rs211037 polymorphism and the risk of FS remains controversial.This meta-analysis was conducted to investigate the relationship of GABRG2 rs211037 polymorphism with the susceptibility to FS.Methods:MEDLINE,Embase,Cochrane Library and CNKI databases were searched(until April 6,2019)for eligible studies on the relationship between GABRG2 rs211037 polymorphism and FS.We calculated the odds ratios(ORs)by a fixed or random model with the STATA 15.0 software.Subgroup analyses for the ethnicity,the source of the control,and age and sex matching of controls were conducted.Results:A total of 8 studies consisting of 775 FS patients and 5162 controls were included in this study.Based on the overall data,he GABRG2 rs211037 polymorphism was not significantly associated with the risk of FS(TT+CT vs CC:OR=0.95,95%CI 0.64–1.41,P=0.80).Notably,the GABRG2 rs211037 variant was significantly associated with decreased risk of FS in Asian populations(TT vs CT+CC:OR=0.63,95%CI 0.45–0.88,P=0.006),but increased risk in Caucasian populations(CT vs CC:OR=1.56,95%CI 1.14–2.15,P=0.006).Significant associations were also detected when healthy controls out of the whole controls were employed for comparison(TT vs CT+CC:OR=0.59,95%CI 0.45–0.77,P<0.001)and when data from studies with age-and sex-matched controls were used(TT+CT vs CC:OR=0.60,95%CI 0.43–0.86,P=0.001).Conclusion:The GABRG2 rs211037 polymorphism may decrease the risk of FS in Asian populations,while increasing the risk in Caucasian populations.Further well-designed studies with large sample sizes are essential to verify the conclusions in other ethnicities. | Xiaohui Yang Jing Chi Xiaomeng Wang Hongyun Wei Xueping Zheng Yi Hu Song Hu Yongjun Mao Xiaosa Chi | 2021 | Acta Epileptologica2021，3，1： | 0 |
| 16 | Licorice-saponin A3 is a broad-spectrum inhibitor for COVID-19 by targeting viral spike and anti-inflammation显示文摘Currently,human health due to corona virus disease 2019(COVID-19)pandemic has been seriously threatened.The coronavirus severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)spike(S)protein plays a crucial role in virus transmission and several S-based therapeutic approaches have been approved for the treatment of COVID-19.However,the efficacy is compromised by the SARS-CoV-2 evolvement and mutation.Here we report the SARS-CoV-2 S protein receptor-binding domain(RBD)inhibitor licorice-saponin A3(A3)could widely inhibit RBD of SARS-CoV-2 variants,including Beta,Delta,and Omicron BA.1,XBB and BQ1.1.Furthermore,A3 could potently inhibit SARS-CoV-2 Omicron virus in Vero E6 cells,with EC50 of 1.016μM.The mechanism was related to binding with Y453 of RBD determined by hydrogen-deuterium exchange mass spectrometry(HDX-MS)analysis combined with quantum mechanics/molecular mechanics(QM/MM)simulations.Interestingly,phosphoproteomics analysis and multi fluorescent immunohistochemistry(mIHC)respectively indicated that A3 also inhibits host inflammation by directly modulating the JNK and p38 mitogen-activated protein kinase(MAPK)pathways and rebalancing the corresponding immune dysregulation.This work supports A3 as a promising broad-spectrum small molecule drug candidate for COVID-19. | Yang Yi Wenzhe Li Kefang Liu Heng Xue Rong Yu Meng Zhang Yang-Oujie Bao Xinyuan Lai Jingjing Fan Yuxi Huang Jing Wang Xiaomeng Shi Junhua Li Hongping Wei Kuanhui Xiang Linjie Li Rong Zhang Xin Zhao Xue Qiao Hang Yang Min Ye | 2024 | Journal of Pharmaceutical Analysis2024，14，1： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员