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187篇 您的检索式:作者名="Yanfei Li"
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1Effects of organic acids on the leaching process of ion-adsorption type rare earth ore显示文摘To examine the activation of organic acids on the leaching process of ion-adsorption type rare earth ore(IRE-ore), the leaching behavior of rare earth(RE) and zeta potential of IRE-ore were investigated in the absence and presence of carboxylic acids. The results show that all the tested organic acids(acetic acid,malonic acid, citric acid, tartaric acid, succinic acid, and malic acid) can promote RE extraction. At relatively high concentrations of organic acids, the activation efficiency of organic acids on RE extraction is generally consistent with their complexation ability; whereas at their low concentrations, the change of zeta potential on the IRE-ore surface with organic acid concentration and p H has a close association with RE extraction, which indicates that organic acids can impact the surface electrical property of IREore via their adsorption/desorption, and thereby increase/decrease the affinity of RE ions to IRE-ore.Therefore the influence of organic acids on the IRE-ore surface electrical property also plays an important role in RE extraction in addition to their complexation with RE ions.Li Wang Chunfa Liao Youming Yang Haibo Xu Yanfei Xiao Chunhua Yan 2017Journal of Rare Earths2017,35,12:23
2The material and biological characteristics of osteoinductive calcium phosphate ceramics显示文摘The discovery of osteoinductivity of calcium phosphate(Ca-P)ceramics has set an enduring paradigm of conferring biological regenerative activity to materials with carefully designed structural characteristics.The unique phase composition and porous structural features of osteoinductive Ca-P ceramics allow it to interact with signaling molecules and extracellular matrices in the host system,creating a local environment conducive to new bone formation.Mounting evidence now indicate that the osteoinductive activity of Ca-P ceramics is linked to their physicochemical and three-dimensional structural properties.Inspired by this conceptual breakthrough,many laboratories have shown that other materials can be also enticed to join the rank of tissue-inducing biomaterials,and besides the bones,other tissues such as cartilage,nerves and blood vessels were also regenerated with the assistance of biomaterials.Here,we give a brief historical recount about the discovery of the osteoinductivity of Ca-P ceramics,summarize the underlying material factors and biological characteristics,and discuss the mechanism of osteoinduction concerning protein adsorption,and the interaction with different types of cells,and the involvement of the vascular and immune systems.Zhurong Tang Xiangfeng Li Yanfei Tan Hongsong Fan Xingdong Zhang 2018Regenerative Biomaterials2018,5,1:20
3Generation of B Cell-Deficient Pigs by Highly Efficient CRISPR/Cas9-Mediated Gene Targeting显示文摘Generating B cell-deficient mutant is the first step to produce human antibody repertoires in large animal models. In this study, we applied the clustered regularly interspaced short palindromic repeat(CRISPR)/CRISPR-associated(Cas) system to target the JHregion of the pig Ig M heavy chain gene which is crucial for B cell development and differentiation. Transfection of Ig M-targeting Cas9 plasmid in primary porcine fetal fibroblasts(PFFs) enabled inducing gene knock out(KO) in up to 53.3% of colonies analyzed, a quarter of which harbored biallelic modification, which was much higher than that of the traditional homologous recombination(HR). With the aid of somatic cell nuclear transfer(SCNT) technology, three piglets with the biallelic Ig M heavy chain gene mutation were produced. The piglets showed no antibody-producing B cells which indicated that the biallelic mutation of the Ig M heavy chain gene effectively knocked out the function of the Ig M and resulted in a B cell-deficient phenotype. Our study suggests that the CRISPR/Cas9 system combined with SCNT technology is an efficient genome-editing approach in pigs.Fengjiao Chen Ying Wang Yilin Yuan Wei Zhang Zijian Ren Yong Jin Xiaorui Liu Qiang Xiong Qin Chen Manling Zhang Xiaokang Li Lihua Zhao Ze Li Zhaoqiang Wu Yanfei Zhang Feifei Hu Juan Huang Rongfeng Li Yifan Dai 2015Journal of Genetics and Genomics2015,42,8:15
4Non-ammonia enrichment of rare earth by magnesium oxide from rare earth leaching liquor in magnesium salt system显示文摘In order to solve the problem of ammonia-nitrogen pollution in the enrichment process of the ionadsorption type rare earth ore,the technology of non-ammonia precipitation with magnesium oxide precipitant was carried out.It is determined that the rare earth precipitation efficiency is 99.6%and the purity of rare earth concentrates is only 85.89 wt%under the optimum precipitation conditions.And the contents of MgO,SO3 and Al2O3 in the rare earth concentrates are 5.12 wt%,6.77 wt%and 1.78 wt%,respectively.Furthermore,the thermo-decomposition process of precipitates was investigated by TGDSC,XRD and FI-IR.The thermal decomposition process consists of two stages:the dehydration of rare earth hydroxide and alkaline rare earth sulfate within 900℃and the thermal decomposition of RE2O2SO4 at 900-1300℃.Therefore,a high-temperature calcinations method for removing SO3 from precipitates is proposed.When the precipitates are calcined at 1300℃for 2 h,the rare earth concentrates with a purity of 92.03 wt%can be acquired.Moreover,the content of SO3 in the concentrate is only 0.46 wt%.In the MgO precipitation and high-temperature calcinations process,the raw material cost is low and the quality of rare earth concentrates is acceptable.It could have great significance for nonammonia enrichment of rare earth from the rare earth leaching liquor,and finally solve the problem of ammonia nitrogen in the extraction process of the ion-adsorption type rare earth ore within magnesium salt system.Li Huang Guohua Gao Ran Wu Qian Zhang Fuguo Lai Yanfei Xiao 2019Journal of Rare Earths2019,37,8:14
5Review of Hydrogen Embrittlement in Metals: Hydrogen Diffusion, Hydrogen Characterization, Hydrogen Embrittlement Mechanism and Prevention显示文摘Hydrogen dissolved in metals as a result of internal and external hydrogen can affect the mechanical properties of the metals, principally through the interactions between hydrogen and material defects. Multiple phenomena such as hydrogen dissolution, hydrogen diffusion, hydrogen redistribution and hydrogen interactions with vacancies, dislocations, grain boundaries and other phase interfaces are involved in this process. Consequently, several hydrogen embrittlement(HE) mechanisms have been successively proposed to explain the HE phenomena, with the hydrogen-enhanced decohesion mechanism, hydrogenenhanced localized plasticity mechanism and hydrogen-enhanced strain-induced vacancies being some of the most important. Additionally, to reduce the risk of HE for engineering structural materials in service, surface treatments and microstructural optimization of the alloys have been suggested. In this review, we report on the progress of the studies on HE in metals, with a particular focus on steels. It focuses on four aspects:(1) hydrogen diffusion behavior;(2) hydrogen characterization methods;(3) HE mechanisms;and(4) the prevention of HE. The strengths and weaknesses of the current HE mechanisms and HE prevention methods are discussed, and specific research directions for further investigation of fundamental HE mechanisms and methods for preventing HE failure are identified.Xinfeng Li Xianfeng Ma Jin Zhang Eiji Akiyama Yanfei Wang Xiaolong Song 2020Acta Metallurgica Sinica(English Letters)2020,33,6:13
6Effects of Rare Earth elements on microstructure evolution and mechanical properties of 718H pre-hardened mold steel显示文摘718 H Pre-ha rdened mold steels with diffe rent Rare Earth(RE) contents were prepared to investigate the influence of RE on microstructure evolution and mechanical properties through a series of experiments and theoretical analysis.The results indicated that the toal oxygen(T.O) content decreased from 15 ppm to 6 ppm with 0.022 wt% RE addition,which is attributed to the active chemical properties of RE elements.For test steels,RE additions of 0.012 wt% and 0.022 wt% were significantly effective for refining inclusions by eliminating 11.5% large-sized inclusions with diameter exceeding 10 μm compared with that of ORE steel.RE addition contributed to modify irregular MnS and Al2 O3 inclusions into ellipsoidal RE-inclusions(RE2 O,RES,RE2 O2 S and REAlO3).The purification of molten steel and the modification of inclusions by RE treatment have significant effects on improvement of the fatigue crack growth tests(FCG) inhibition ability and impact energy as well as the isotropy.However,excessive addition of RE elements(0.07 wt%)seriously reduced the impact energy,ultimate tensile strength and FCG inhibition ability due to rapidly increase of the volume fraction of large-sized inclusions.In addition to the inclusions formed by RE treatment,trace solid solution RE atoms improve the stability of undercooled austenite,resulting in the transformation region of bainite and perlite of 0.07 RE steel shifting to the bottom right and prolonging the incubation period compared with that of ORE steel.Hanghang Liu Paixian Fu Hongwei Liu Yanfei Cao Chen Sun Ningyu Du Dianzhong Li 2020Journal of Materials Science & Technology2020,47,15:11
7Regional Distribution and Sustainable Development Strategy of Mineral Resources in China显示文摘This paper summarizes the distribution and production layout of the major mineral resources in China,including coal,iron ore,copper and bauxite,from a national perspective.It also identifies the incompatibility between the mineral resources distribution and regional economic development.Significant issues with China's mineral resource industry cause challenges for the sustainable development of both the mining industry and the national socio-economy.The sustainability of regional mineral resources and the environmental pollution by mining in the western China were also analyzed.Results show that the distribution of China's mineral resources is misaligned with its regional layout of economic development.China's mineral resources have been over-exploited,and the mineral resources production in the eastern China is unsustainable.The continuously expanding production of mineral resources in the western China has heavily endangered the ecological environment.We propose strategies to boost the sustainable development of mineral resources,including measures to accelerate economic development and enhance the sustainability of domestic mineral resources.We also offer suggestions for scientifically planning the mineral resource prospecting and exploitation and regional economic layout,as well as for proactively undertaking industry transfer in the eastern China and raising the environmental benchmark requirements for the mineral industry in the central and western China.LI Chaofeng WANG Anjian CHEN Xiaojin CHEN Qishen ZHANG Yanfei LI Ying 2013Chinese Geographical Science2013,23,4:11
8A Domestication-Associated Gene GmPRR3b Regulates the Circadian Clock and Flowering Time in Soybean显示文摘Improved soybean cultivars have been adapted to grow at a wide range of latitudes,enabling expansion of cultivation worldwide.However,the genetic basis of this broad adaptation is still not clear.Here,we report the identification of GmPRR3b as a major flowering time regulatory gene that has been selected during domestication and genetic improvement for geographic expansion.Through a genome-wide association study of a diverse soybean landrace panel consisting of 279 accessions,we identified 16 candidate quantitative loci associated with flowering time and maturity time.The strongest signal resides in the known flowering gene E2,verifying the effectiveness of our approach.We detected strong signals associated with both flowering and maturity time in a genomic region containing GmPRR3b.Haplotype analysis revealed that GmPRR3bH6 is the major form of GmPRR3b that has been utilized during recent breeding of modern cultivars.mRNA profiling analysis showed that GmPRR3bH6 displays rhythmic and photoperiod-dependent expression and is preferentially induced under long-day conditions.Overexpression of GmPRR3bH6 increased main stem node number and yield,while knockout of GmPRR3bH6 using CRISPR/Cas9 technology delayed growth and the floral transition.GmPRR3bH6 appears to act as a transcriptional repressor of multiple predicted circadian clock genes,including GmCCAIa,which directly upregulates J/GmELF3a to modulate flowering time.The causal SNP(Chr12:5520945)likely endows GmPRR3bH6 a moderate but appropriate level of activity,leading to early flowering and vigorous growth traits preferentially selected during broad adaptation of landraces and improvement of cultivars.Cong Li Ying-hui Li Yanfei Li Hongfeng Lu Huilong Hong Yu Tian Hongyu Li Tao Zhao Xiaowei Zhou Jun Liu Xinan Zhou Scott A.Jackson Bin Liu Li-juan Qiu 2020Molecular Plant2020,13,5:11
9Transcriptional landscape of rice roots at the single-cell resolution显示文摘There are two main types of root systems in flowering plants,namely taproot systems of dicots and fibrous root systems found in monocots.Despite this fundamental split,our current knowledge of cellular and molecular mechanism driving root development is mainly based on studies of the dicot model Arabidopsis.However,the world major crops are monocots and little is known about the transcriptional programs underlying cell-type specification in this clade.Here,we report the transcriptomes of more than 20000 single cells derived from root tips of two agronomically important rice cultivars.Using combined computational and experimental analyses we were able to robustly identify most of the major cell types and define novel cell-type-specific marker genes for both cultivars.Importantly,we found divergent cell types associated with specific regulatory programs,including phytohormone biosynthesis,signaling,and response,which were well conserved between the two rice cultivars.In addition,we detected substantial differences between the cell-type transcript profiles of Arabidopsis and rice.These species-specific features emphasize the importance of analyzing tissues across diverse model species,including rice.Taken together,our study provides insight into the transcriptomic landscape of major cell types of rice root tip at single-cell resolution and opens new avenues to study cell-type specification,function,and evolution in plants.Qing Liu Zhe Liang Dan Feng Sanjie Jiang Yifan Wang Zhuoying Du Ruoxi Li Guihua Hu Pingxian Zhang Yanfei Ma Jan ULohmann Xiaofeng Gu 2021Molecular Plant2021,14,3:9
10Expert consensus on the glycemic management of critically ill patients显示文摘Introduction The incidence of hyperglycemia is 40-60%in critically ill patients and is up to 60-80%in those who have undergone car-diac surgery.[1]The results of an epidemiological study in the United States showed that 28.6%of diabetic patients and 9.3%of non-diabetic patients had elevated mean daily glucose on the day of ICU admission.[2]In critically ill patients,elevated blood glucose is primarily the result of stress,and stress-induced hy-perglycemia is an independent risk factor associated with prog-nosis,regardless of a previous diagnosis of diabetes.Nutritional therapy has become an integral treatment option for patients in the ICU,[3,4]though nearly 30%of patients with enteral nu-trition and 44-50%with parenteral nutrition(PN)experience elevated glucose.[5,6]Intensive insulin therapy(IIT)is an impor-tant treatment for controlling hyperglycemia in critically ill pa-tients,but it also carries a corresponding risk of hypoglycemia.Zhixiong Wu Jiao Liu Dong Zhang Kai Kang Xiangrong Zuo Qianghong Xu Aijun Pan Wei Fang Fen Liu You Shang Haiyan Yin Juntao Hu Jinglun Liu Jiangquan Fu Wei Zhang Yuan Zong Min Shao Feng Zhao Mei Meng Yanfei Mao Yingchuan Li Dechang Chen 2022Journal of Intensive Medicine2022,2,3:9
11Enhanced methane production in an anaerobic digestion and microbial electrolysis cell coupled system with co-cultivation of Geobacter and Methanosarcina显示文摘The anaerobic digestion(AD)and microbial electrolysis cell(MEC)coupled system has been proved to be a promising process for biomethane production.In this paper,it was found that by co-cultivating Geobacter with Methanosarcina in an AD–MEC coupled system,methane yield was further increased by 24.1%,achieving to 360.2 m L/g-COD,which was comparable to the theoretical methane yield of an anaerobic digester.With the presence of Geobacter,the maximum chemical oxygen demand(COD)removal rate(216.8 mg COD/(L·hr))and current density(304.3 A/m_3)were both increased by 1.3 and 1.8 fold compared to the previous study without Geobacter,resulting in overall energy efficiency reaching up to 74.6%.Community analysis demonstrated that Geobacter and Methanosarcina could coexist together in the biofilm,and the electrochemical activities of both were confirmed by cyclic voltammetry.Our study observed that the carbon dioxide content in total gas generated from the AD reactor with Geobacter was only half of that generated from the same reactor without Geobacter,suggesting that Methanosarcina may obtain the electron transferred from Geobacter for the reduction of carbon dioxide to methane.Taken together,Geobacter not only can improve the performance of the MEC system,but also can enhance methane production.Qi Yin Xiaoyu Zhu Guoqiang Zhan Tao Bo Yanfei Yang Yong Tao Xiaohong He Daping Li Zhiying Yan 2016Journal of Environmental Sciences2016,28,4:9
12Recovery of rare earths from ion-absorbed rare earths ore with MgSO_4-ascorbic acid compound leaching agent显示文摘The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO_4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO_4 and environmentally friendly leaching.Fuguo Lai Li Huang Guohua Gao Run Yang Yanfei Xiao 2018Journal of Rare Earths2018,36,5:8
13Recent Progress in Automotive Gasoline Direct Injection Engine Technology显示文摘Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.Shijin Shuai Xiao Ma Yanfei Li Yunliang Qi Hongming Xu 2018Automotive Innovation2018,1,2:8
14Development and utilization of a new chemically-induced soybean library with a high mutation density显示文摘Mutagenized populations have provided important materials for introducing variation and identifying gene function in plants. In this study, an ethyl methanesulfonate(EMS)-induced soybean(Glycine max) population,consisting of 21,600 independent M_2 lines, was developed.Over 1,000 M_(4(5))families, with diverse abnormal phenotypes for seed composition, seed shape, plant morphology and maturity that are stably expressed across different environments and generations were identified. Phenotypic analysis of the population led to the identification of a yellow pigmentation mutant, gyl, that displayed significantly decreased chlorophyll(Chl) content and abnormal chloroplast development. Sequence analysis showed that gyl is allelic to Minn Gold, where a different single nucleotide polymorphism variation in the Mg-chelatase subunit gene(ChlI1a) results in golden yellow leaves. A cleaved amplified polymorphic sequence marker was developed and may be applied to marker-assisted selection for the golden yellow phenotype in soybean breeding. We show that the newly developed soybean EMS mutant population has potential for functional genomics research and genetic improvement in soybean.Zhongfeng Li Lingxue Jiang Yansong Ma Zhongyan Wei Huilong Hong Zhangxiong Liu Jinhui Lei Ying Liu Rongxia Guan Yong Guo Longguo Jin Lijuan Zhang Yinghui Li Yulong Ren Wei He Ming Liu Nang Myint Phyu Sin Htwe Lin Liu Bingfu Guo Jian Song Bing Tan Guifeng Liu Maiquan Li Xianli Zhang Bo Liu Xuehui Shi Sining Han Sunan Hua Fulai Zhou Lili Yu Yanfei Li Shuang Wang Jun Wang Ruzhen Chang Lijuan Qiu 2017Journal of Integrative Plant Biology2017,59,1:6
15Mesoporous silica SBA-15 functionalized with phosphonate and amino groups for uranium uptake显示文摘Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands.In this work,phosphonate-amino bifunctionalized mesoporous silica SBA-15(PA-SBA-15) as U(VI) sorbent was fabricated through post-grafting method.The obtained mesoporous silica was characterized by SEM,XRD,NMR and nitrogen sorption/desorption experiments,which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area.The adsorptivity of PA-SBA-15 for U(VI) from aqueous solution was investigated using batch sorption technique under different experimental conditions.The preliminary results show that the U(VI) sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h,and the U(VI) uptake is as large as 373 mg/g at pH 5.5 under 95 ℃.The sorption isotherm has been successfully modeled by the Langmuir isotherm,suggesting a monolayer homogeneous sorption of U(VI) in PA-SBA-15.The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution.The thermodynamics research shows that the sorption is a feasible and endothermic process.Based on these results,PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U(VI) ions from waste water and enrichment of U(VI) from a solution at a very low level.WANG XiaoLiang YUANLiYong WANG YanFei LI ZiJie LIU YaLan FENG YiXiao ZHAO YuLiang CHAI ZhiFang SHI WeiQun 2012Science China Chemistry2012,55,9:6
16Optimizing the CRISPR/Cas9 system for genome editing in grape by using grape promoters显示文摘The efficacy of the CRISPR/Cas9 system in grapevine(Vitis vinifera L.)has been documented,but the optimization of this system,as well as CRISPR/Cas9-mediated multiplex genome editing,has not been explored in this species.Herein,we identified four VvU3 and VvU6 promoters and two ubiquitin(UBQ)promoters in grapevine and demonstrated that the use of the identified VvU3/U6 and UBQ2 promoters could significantly increase the editing efficiency in grape by improving the expression of sgRNA and Cas9,respectively.Furthermore,we conducted multiplex genome editing using the optimized CRISPR/Cas9 vector that contained the conventional multiple sgRNA expression cassettes or the polycistronic tRNA-sgRNA cassette(PTG)by targeting the sugar-related tonoplastic monosaccharide transporter(TMT)family members TMT1 and TMT2,and the overall editing efficiencies were higher than 10%.The simultaneous editing of TMT1 and TMT2 resulted in reduced sugar levels,which indicated the role of these two genes in sugar accumulation in grapes.Moreover,the activities of the VvU3,VvU6,and UBQ2 promoters in tobacco genome editing were demonstrated by editing the phytoene desaturase(PDS)gene in Nicotiana benthamiana leaves.Our study provides materials for the optimization of the CRISPR/Cas9 system.To our knowledge,our simultaneous editing of the grape TMT family genes TMT1 and TMT2 constitutes the first example of multiplex genome editing in grape.The multiplex editing systems described in this manuscript expand the toolbox of grape genome editing,which would facilitate basic research and molecular breeding in grapevine.Chong Ren Yanfei Liu Yuchen Guo Wei Duan Peige Fan Shaohua Li Zhenchang Liang 2021Horticulture Research2021,8,1:6
17Disproportionate Increase of New Diagnosis of HIV/AIDS Infection by Sex and Age--China, 2007−2018显示文摘What is already known about this topic?The annual rates of newly diagnosed HIV/AIDS among total population is increasing in China,yet HIV/AIDS in older adults has received little attention.What is added by this report?The overall rates of new diagnosis of HIV/AIDS per 100,000 populations increased 3.26 and 2.18 times among male and female in all ages from 2007 to 2018,respectively.Among adults aged≥60 years,the rate increased 10.41 times(1.35 to 14.06 per 100,000)from 2007 to 2018.Male adults aged 60–69 and 70–79 years and female aged 50–59 and 60–69 years had the highest increasing rates among all groups.What are the implications for public health practice?This study highlights the need to strengthen HIV/AIDS prevention among older adults.Health education and other effective measurements might be used to prevent HIV/AIDS among this group.Yewu Zhang Chang Cai Xiaofeng Wang Yanfei Li Houlin Tang Jiaqi Ma 2020China CDC weekly2020,2,5:5
18Epigallocatechin-3-gallate inhibits angiotensin Il-induced cardiomyocyte hypertrophy via regulating Hippo signaling pathway in H9c2 rat cardiomyocytes显示文摘AngiotensinⅡ(All) has been well known to induce cardiomyocyte hypertrophy. Epigallocatechin-3-gallate (EGCG) is the main active comp on ent of green tea and it has bee n show n to exhibit strong cardioprotective potential, although the underlying molecular mechanisms remain unclear. In this study, we investigated the role and mechanism of EGCG in preventing All-induced cardiomyocyte hypertrophy using rat H9c2 cardiomyocytes cells. Reactive oxygen species assay, cell size, and mRNA expression of cardiac hypertrophy markers ANP and BNP were assessed in response to All treatment. In addition, expression of proteins involved in Hippo signaling pathway were determined by western blot analysis. We found that All treatment resulted in significant upregulation of ANP and BNP expression levels and increase in H9c2 cell size, which were markedly attenuated by EGCG treatment. Furthermore, our results suggested that EGCG inhibited Allinduced cardiac hypertrophy via regulating the Hippo signaling pathway. Therefore, EGCG may be an effective agent for preventing cardiac hypertrophy.Yuan Ma Yongjia Hu Jiawen Wu Junru Wen Sen Li Lijuan Zhang Jie Zhang Yanfei Jue Li 2019Acta Biochimica et Biophysica Sinica2019,51,4:4
19Strengthening in Al-,Mo-or Ti-doped CoCrFeNi high entropy alloys:A parallel comparison显示文摘In the current work,a parallel comparison of the influence of Al,Mo and Ti,on the microstructure and strengthening of the CoCrFeNi alloy was conducted.To achieve this,inconsistencies on variables including the extent of alloying,thermomechanical processing and property-evaluation method were avoided.Microstructurally,following cold-rolling,annealing of the 4 at.%Al-doped alloys at 800-1000℃ did not result in phase separation;nevertheless,that of the 4 at.%Mo-and Ti-doped alloys led to the respective formation ofσandηphase and,consequently,caused extra strengthening through the Orowan dislocation bypassing mechanism.Our systematic qualitative analysis and DFT calculations showed that Al and Ti are more effective than Mo in reducing the stacking fault energy(SFE)of the CoCrFeNi alloy,because they can induce more considerable deformation of electronic density,making the gliding of atomic layers easier.Following identical thermomechnical processing,Al-,Mo-,and Ti-doping causes different extent of solid solution strengthening and grain boundary strengthening.Mo causes the most pronounced solid solution strengthening but does not benefit the grain boundary strengthening;in contrast,the effectiveness of grain boundary strengthening is boosted by the doping Al and Ti.Current analyses support that Labusch instead of Fleischer mechanism is applicable to explain the differences in solid solution strengthening,and the observed differences in grain boundary strengthening arise from the different tendency of Al,Mo and Ti to reduce the SFE of CoCrFeNi.In addition,we determined the value of the dimensionless parameter f in the Labusch model for CoCrFeNi-based alloys and observed a close relation between Hall-Petch slope and SFE.Although more in-depth studies are needed to provide full and mechanistic understandings,both these findings in fact presents significant values toward designing novel singlephase high-strength CoCrFeNi-based alloys through manipulating the solid solution and grain boundary strengthening by compositional tuning.Xi Li Zhongtao Li Zhenggang Wu Shijun Zhao Weidong Zhang Hongbin Bei Yanfei Gao 2021Journal of Materials Science & Technology2021,,35:4
20On the effective inversion by imposing a priori information for retrieval of land surface parameters显示文摘The anisotropy of the land surface can be best described by the bidirectional reflectance distribution function (BRDF). As the field of multiangular remote sensing advances, it is increasingly probable that BRDF models can be inverted to estimate the important biological or climatological parameters of the earth surface such as leaf area index and albedo. The state-of-the-art of BRDF is the use of the linear kernel-driven models, mathematically described as the linear combination of the isotropic kernel, volume scattering kernel and geometric optics kernel. The computational stability is characterized by the algebraic operator spectrum of the kernel-matrix and the observation errors. Therefore, the retrieval of the model coefficients is of great importance for computation of the land surface albedos. We first consider the smoothing solution method of the kernel-driven BRDF models for retrieval of land surface albedos. This is known as an ill-posed inverse problem. The ill-posedness arises from that the linear kernel driven BRDF model is usually underdetermined if there are too few looks or poor directional ranges, or the observations are highly dependent. For example, a single angular observation may lead to an under-determined system whose solution is infinite (the null space of the kernel operator contains nonzero vectors) or no solution (the rank of the coefficient matrix is not equal to the augmented matrix). Therefore, some smoothing or regularization technique should be applied to suppress the ill-posedness. So far, least squares error methods with a priori knowledge, QR decomposition method for inversion of the BRDF model and regularization theories for ill-posed inversion were developed. In this paper, we emphasize on imposing a priori information in different spaces. We first propose a gen-eral a priori imposed regularization model problem, and then address two forms of regularization scheme. The first one is a regularized singular value decomposition method, and then we propose a retrieval method in l1 space. We show that the proposed method is suitable for solving land surface parameter retrieval problem if the sampling data are poor. Numerical experiments are also given to show the efficiency of the proposed methods.WANG YanFei MA ShiQian YANG Hua WANG JinDi LI XiaoWen 2009Science China Earth Sciences2009,52,4:4
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