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Cryptanalysis and improvement of a certificateless encryption scheme in the standard model

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Frontiers of Computer Science 2014年第1期8卷 163-173页

作者： Lin CHENG Qiaoyan wen Zhengping jin Hua zhang State Key Laboratory of Networking and Switch Technology Beijing University of Posts and Telecommunications Beijing 100876 China

Certificateless public key cryptography elimi- nates inherent key escrow problem in identity-based cryptog- raphy, and does not yet requires certificates as in the tradi- tional public key infrastructure. In this paper, we give crypt- analysis to Hwang et al.＇s certificateless encryption scheme which is the first concrete certificateless encryption scheme that can be proved to be secure against ＂malicious-but- passive＂ key generation center （KGC） attack in the stan- dard model. Their scheme is proved to be insecure even in a weaker security model called ＂honest-but-curious＂ KGC at- tack model. We then propose an improved scheme which is really secure against ＂malicious-but-passive＂ KGC attack in the standard model.

关键词： certificateless public key cryptography stan-dard model provable security

Effect of Nb addition on microstructure and mechanical properties of 25CrNiMoV(DZ2)steel for high-speed railway axles

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Journal of Iron and Steel Research International 2022年第5期29卷 802-809页

作者： jin-wen zhang Yan-guang Cao Cheng-guo zhang Zhao-dong Li wen-xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Technology Center Taiyuan Iron and Steel(Group)Co.Taiyuan030003ShanxiChina Department of Structural Steels Central Iron and Steel Research InstituteBeijing100081China Locomotive and Car Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China

The microstructure,precipitates and properties of 25CrNiMoV(DZ2)steel for high-speed railway axles with different Nb contents were investigated by means of optical microscopy,scanning electron microscopy,electron back-scattering diffraction,transmission electron microscopy and physicochemical phase *** results show that the grain size of the original austenite of the test steels decreases from 20.5 to 14.2 and 10.8μm after adding 0.026 and 0.039 wt.%Nb to a 25CrNiMoV steel,***,the block width of the tempered martensite in the test steels is refined from 1.91 to 1.72 and 1.60µm,***-type precipitates in 25CrNiMoV steel are mainly VC,while(Nb,V)C gradually precipitates when Nb is microalloyed,and the amount of precipitates increases with increasing Nb *** strengthening mechanism analysis,it is found that grain refinement strengthening is the primary way to increase the *** improvement in the yield strength with increasing Nb content is attributed to a significant increase in precipitation strengthening,grain refinement strengthening and dislocation strengthening.

关键词： High-speed railway axle steel Nb microalloying Precipitate Strengthening mechanism

Epithelial defect repair in the auricle and auditory meatus by grafting with cultured adipose-derived mesenchymal stem cell aggregate-extracellular matrix

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Chinese Medical Journal 2019年第6期132卷 680-689页

作者： wen-jin zhang Lei-Guo Ming Jian-Jun Sun Center of Otolaryngology Head and Neck Surgery Chinese PLA Navy General Hospital Beijing 100048 China School of Postgraduate Anhui Medical University Hefei Anhui 230032 China State Key Laboratory of Military Stomatology Center for Tissue Engineering School of Stomatology Fourth Military Medical University Xi'an Shaanxi 710032 China Research and Development Center for Tissue Engineering Fourth Military Medical University Xi'an Shaanxi 710032 China

Background: Several patients experience persistent otorrhea after a flawless surgical procedure because of insufficient epithelial healing. Several efforts, such as autologous tissue allograft and xenograft, have been made to halt otorrhea. However, a stable technology to induce temporal epithelial repair is yet to be established. Therefore, this study aims to investigate whether implantation of seeding adipose-derived mesenchymal stem cell (ADMSC) aggregates on extracellular matrix (ECM;herein, ADMSC aggregate-ECM) into damaged skin wound promotes skin regeneration. Methods: ADMSC aggregate-ECM was prepared using a previously described procedure that isolated ADMSCs from rabbits and applied to the auricle and auditory meatus wound beds of New Zealand white rabbits. Wound healing was assessed by general observation and hematoxylin and eosin (H&E) staining. Secretion of growth factor of the tissue was evaluated by western blotting. Two other groups, namely, ECM and control, were used. Comparisons of three groups were conducted by one-way analysis of variance analysis. Results: ADMSCs adhered tightly to the ECM and quickly formed cell sheets. At 2 weeks, general observation and H&E staining indicated that the wound healing rates in the ADMSC aggregate-ECM (69.02±6.36%) and ECM (59.32 + 4.10%) groups were higher than that in the control group (43.74± 12.15%;P=0.005, P<0.001, respectively) in ear auricle excisional wounds. At 7 weeks, The scar elevation index was evidently reduced in the ADMSC aggregate-ECM (2.08±0.87) and ECM (2.31 ±0.33) groups compared with the control group (4.06 ±0.45;P < 0.001, P < 0.001, respectively). In addition, the scar elevation index of the ADMSC aggregate-ECM group reached the lowest rate 4 weeks in advance. In auditory meatus excisional wounds, the ADMSC aggregate-ECM group had the largest range of normal skin-like structure at 4 weeks. The ADMSC aggregate-ECM and ECM groups secreted increased amounts of growth factors that contributed to

关键词： Adipose-derived mesenchymal stem cell Extracellular matrix Otorrhea Rabbit Skin regeneration Wound healing

Epidemiology and region-specific risk factors for low Apgar scores in China:a nationwide study

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World Journal of Pediatrics 2022年第2期18卷 135-141页

作者： Yi-wen Wang Yan Chen Yan-Hong Ming jin-wen zhang Kun Sun Jun zhang Yong-Jun zhang Department of Neonatology Xinhua HospitalShanghai Jiao Tong University School of Medicine1665 Kongjiang RoadShanghai 200092China Department of Obstetrics and Gynecology Hospital of Obstetrics and GynecologyFudan UniversityShanghaiChina Shanghai Key Laboratory of Embryo Original Diseases The International Peace Maternity&Child Health HospitalShanghai Jiao Tong University School of MedicineShanghaiChina Department of Pediatrics Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina Ministry of Educaticn-Shanghai Key Laboratory of Children's Env ironmental Health Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

Background Neonatal asphyxia is a serious public health *** study aimed to determine the epidemiology and region-specific risk factors for low Apgar scores,an important proxy for neonatal asphyxia,in China from 2015 to *** The China Labor and Delivery Survey was a multicenter cross-sectional study including 96 hospitals distributed in 24(out of 34)*** regression analysis was performed to examine the risk factors for a low Apgar score(<7).Correspondence analyses were performed among neonates with low Apgar scores to explore the relationship between risk factors and geographical *** population attributable risk percentage(PAR%)was calculated for each region-specific risk *** A total of 72,073 live births,including 320 births with low Apgar scores,were used for the analysis,giving a weighted rate of 3.9/1000 live *** was a substantial difference in the incidence of low Apgar scores by geographic region,from 2.3/1000 live births in East China to 10.9/1000 live births in Northeast *** and obstetric factors are the major region-specific risk *** Southwest China,hypertensive disorders in pregnancy were more important contributors,with PAR% being 74.47%;in North and Northwest China,pre-pregnancy underweight was a more significant factor,with PAR% of 62.92%;in East China,infants born between 0:00 *** 7:59 *** a key factor,with PAR% of 80.44%.Conclusion Strategies based on region-specific risk factors should be considered to reduce the burden of low Apgar scores in China.

关键词： Apgar score China Epidemiology Risk factor

Programmed death 1 and programmed death ligand 1 expressions in patients with chronic hepatitis B

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Hepatobiliary & Pancreatic Diseases International 2013年第4期12卷 394-399页

作者： wen-jin zhang Chuan-Hui Peng Shu-Sen Zheng Division of Hepatobiliary Pancreatic Surgery First Affiliated Hospital Zhejiang University School of Medicine

BACKGROUND: The role of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) in persistent HBV infection is controversial. Increasing PD-1 and PD-L1 expression has been found in hepatitis B patients during immune clearance phase, but not in HBV-tolerant patients. We investigated PD-1 and PD-L1 expression and inflammation in chronic hepatitis B. METHODS: Twenty patients with chronic hepatitis B participated in this study. Fifteen patients were in the immune clearance phase, and 5 were in the immune inactive phase. Circulating HBV-specific T cells were analyzed by flow cytometric detection of major histocompatibility complex (MHC) class I peptide complexes, known as pentamers. Intra-hepatic PD-1 and PD-L1 expressions were analyzed by immunostaining. RESULTS: The frequency of pentamers, including core 18-27 (1.88%±0.36%), env 335-343 (1.85%±0.37%), and pol 575-583 (1.56%±0.29%) was 8.30-, 7.71- and 8.48-fold greater during immune clearance phase than those during the immune inactive phase. In addition, more than 70% of circulating pentamers were PD-1 positive. During immune clearance phase, the numbers of intra-hepatic PD-1 and PD-L1 positive cells were 108±23/HPF and 97±20/HPF respectively, in contrast, there was a paucity of PD-1 and PD-L1 positive cells in the immune inactive phase. The numbers of intra-hepatic PD-1 and PD-L1 positive cells were positively correlated with serum alanine aminotransferase and the number of intra-hepatic CD8 + T cells. Immunofluorescence showed that almost all of the intra- hepatic CD8 + T cells were PD-1 and CCR6 positive. These cells aggregated around macrophage inflammatory protein-3 alpha (MIP3α) positive cells and mixed with PD-L1 positive ***: PD-1 and PD-L1 expressions were significantly correlated with inflammation. CCR6 and PD-1 co-expressed in the same cells; these cells were increased both in circulation and the inflamed liver and aggregated around MIP3α positive cells. The mixture of CCR6 and PD-1, M

关键词： programmed death 1 receptor hepatitis B, chronic liver

Isolation and Structural Indentification of Herbicidal Toxin Fractions Produced by Pythium aphanidermatum

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Agricultural Sciences in China 2010年第7期9卷 995-1000页

作者： zhang Li-hui KANG Zhan-hai XU Jiao XU wen-chao zhang jin-lin College of Plant Protection Agricultural University of Hebei Baoding 071001 P.R. China

In order to understand the compsition and structure of herbicidal component of Pythium aphanidermatum,the isolation and structural indentification were *** culture filtrate was extracted by ethyl acetate,petroleum,and chloroform with the same volume respectively and the activity of the crude toxin was *** toxin was separated by using the method of thin layer chromatography（TLC）,then the main fraction was separated by HPLC,and the structure was analyzed by the sepctrum of IR,13C-NMR and *** results showed that the ethyl acetate extracts had the strongest herbicidal *** the method of TLC,the bioassay results showed that the extracts with Rf 0.19 had the strongest effect on weeds and the inhibition to Digitaria sanguinalis and Amaranthus retroflexus reached five levels,and the component was proved to be dimethyl o-phthalate from the spectrum of IR,13C-NMR and 1HNMR,which was one of the components from the toxin,and it had herbicidal activity.

关键词： Pythium aphanidermatum toxin herbicidal structure identification

Postreperfusion hyperkalemia in liver trans-plantation using donation after cardiac death grafts with pathological changes

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Hepatobiliary & Pancreatic Diseases International 2016年第5期15卷 487-492页

作者： wen-jin zhang Wei-Liang Xia Hui-Yun Pan Shu-Sen Zheng Division of Hepatobiliary Pancreatic Surgery First Affiliated Hospital Zhejiang University School of Medicine Hangzhou 310003 China Geriatrics Center First Afifliated Hospital Zhejiang University School of Medicine Hangzhou 310003 China

BACKGROUND: With the increasing use of donation after cardiac death (DCD), especially of the graft liver with steatosis or other pathological changes, the frequency of postreperfu-sion hyperkalemia in liver transplantation has increased sig-niifcantly. The present study aimed to determine the factors associated with developing postreperfusion hyperkalemia in liver transplantation from DCD. METHODS: One hundred thirty-one consecutive adult pa-tients who underwent orthotopic liver transplantation from DCD were retrospectively studied. Based on serum potassium within 5 minutes after reperfusion, recipients were divided into two groups: hyperkalemia and normokalemia. According to preoperative biopsy results, the DCD graft livers were clas-siifed into ifve categories. Univariate analysis was performed using Chi-square test to identify variables that were signiif-cantly different between two groups. Multivariate logistic regression was used to conifrm the risk factors of developing hyperkalemia and postreperfusion syndrome. Correlation analysis was used to identify the relationship between the serum concentration of potassium within 5 minutes after re-perfusion and the difference in mean arterial pressure values before and within 5 minutes after reperfusion. RESULTS: Twenty-two of 131 liver recipients had hyperkale-mia episodes within 5 minutes after reperfusion. The rate of hyperkalemia was signiifcantly higher in recipients of macro-steatotic DCD graft liver (78.6%,P<0.001) than that in recipi-ents of non-macrosteatotic DCD graft liver. The odds ratio of developing postreperfusion hyperkalemia in recipients of macrosteatotic DCD graft liver was 51.3 (P<0.001). Macroste-atosis in the DCD graft liver was an independent risk factor of developing hyperkalemia within 5 minutes after reperfusion. The highest rate of postreperfusion syndrome also occurred in the recipients with macrosteatotic DCD graft liver (71.4%, P<0.001). A strong relationship existed betwee

关键词： liver transplantation hyperkalemia reperfusion injury macrosteatosis

In situ embedded bismuth nanoparticles among highly porous carbon fibers for efficient carbon dioxide reduction

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Rare Metals 2024年第9期43卷 4312-4320页

作者： Wei-Jian Guo Ao Zhou wen-wen Cai jin-Tao zhang Key Laboratory for Colloid and Interface Chemistry (Ministry of Education) School of Chemistry and Chemical EngineeringShandong University

Electrocatalysis provides an optimal approach for the conversion of carbon dioxide(CO2) into high-value chemicals, thereby presenting a promising avenue toward achieve carbon neutrality. However, addressing the selectivity and stability challenges of metal catalysts in electrolytic reduction remains a daunting task. In this study, the electrospinning method is employed to fabricate porous carbon nanofibers loaded with bismuth nanoparticles with the help of in situ pyrolysis. The porous carbon nanofibers as conductive support would facilitate the dispersion of bismuth active sites while inhibiting their aggregation and promoting the mass transfer, thus enhancing their electrocatalytic activity and stability. Additionally, nitrogen doping induces electron delocalization in bismuth atoms through metal-support interactions, thus enabling efficient adsorption of intermediates for improving selectivity based on the theoretical calculation. Consequently, Bi@PCNF-500 exhibits the exceptional selectivity and stability across a wide range of potential windows. Notably, its faradaic efficiency(FE) of formate reaches 92.7% in H-cell and94.9% in flow cell, respectively, with good electrocatalytic stability. The in situ characterization and theoretical calculations elucidate the plausible reaction mechanism to obtain basic rules for designing efficient electrocatalyst.

关键词： Carbon dioxide reduction Electron delocalization N-doping Porous carbon nanofiber

Design study of charge-stripping scheme of heavy ion beams for HIAF-BRing

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Nuclear Science and Techniques 2024年第5期35卷 30-41页

作者： Jun-Jie zhang Zhi-You Xu jin-Quan zhang wen-wen Ge Liang-Ting Sun Huan-Yu Zhao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Charge strippers play an essential role in heavy-ion accelerators by stripping the projectile ions to higher charge states to enhance the acceleration efficiency downstream of the *** the high-energy mode of the booster ring(BRing)of the high-intensity heavy-ion accelerator facility,the pre-accelerated ions from the iLinac will be stripped by a carbon foil to higher charge states and then injected into the *** key parameters of the stripper and stripped ions were calculated,and the influence of stripping on the beam quality was *** get high stripping efficiencies,the foil thicknesses and resultant charge state distributions for the typical ions were determined by the code *** equilibrium thickness was obtained for the U beam,while the stripper thicknesses for the Xe and Kr beams were determined based on a compromise between the stripped charge states and the stripping *** energy loss,energy straggling,and emittance growth due to stripping have a non-negligible impact on the transport of the stripped beams and the injection of the ***,these parameters were simulated by *** addition,the foil’s temperature evolution,which greatly affects the foil lifetime,was simulated by *** maximum temperature of the foil bombarded by the U and Xe beams with the nominal parameters will exceed the safe value in terms of the impact of evaporation on the foil’s *** the foil temperature constraint,the highest tolerable beam intensity and the injected ion number into the ring were derived for different beam *** results of this paper will present important reference data for the optimization design and commissioning of the beamline and injection to the BRing for the stripped ions.

关键词： High-intensity heavy-ion accelerator facility Charge stripper Energy spread Thermal analysis Emittance growth Injection turns