检索结果-南通市图书馆

双头菌WH-1环氧乙烷二酸水解酶的克隆和酶学性质的研究（英文）

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2019年第12期20卷 995-1002页

作者： wen-na bao Zi-sheng LUO Shi-wang LIU Yuan-feng WU Pei-lian WEI Gong-nian XIAO Yong LIU College of Biosystems Engineering and Food Science Zhejiang UniversityHangzhou 310058China School of Biological and Chemical Engineering Zhejiang University of Science and TechnologyHangzhou 310023China Zhejiang Provincial Key Laboratory for Chemical and Biological Processing Technology of Farm Products Hangzhou 310023China

目的:克隆双头菌WH-1环氧乙烷二酸水解酶(ORCH)的基因并研究其酶学性质。创新点:首次获得双头菌ORCH的基因,且该酶催化效率高,热稳定性好。方法:柱层析纯化ORCH后,进行酶学性质研究;通过蛋白末端测序和PCR获得其基因序列;通过二级结构... 详细信息

目的:克隆双头菌WH-1环氧乙烷二酸水解酶(ORCH)的基因并研究其酶学性质。创新点:首次获得双头菌ORCH的基因,且该酶催化效率高,热稳定性好。方法:柱层析纯化ORCH后,进行酶学性质研究;通过蛋白末端测序和PCR获得其基因序列;通过二级结构预测和多序列比对进行ORCH序列分析。结论:来源于双头菌WH-1的ORCH是迄今报道的催化效率和热稳定性最好的ORCH,为L(+)-2,3-二羟基丁二酸的生产提供了新的催化剂。

关键词：环氧乙烷二酸水解酶 L(+)-2,3-二羟基丁二酸酶学性质克隆

Feedback of Efficient Shock Acceleration on Magnetic-field Structure Inside Young Type Ia Supernova Remnants

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第6期24卷 236-246页

作者： Jun-Yu Shen Bi-wen bao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan Province Yunnan University Key Laboratory of Statistical Modeling and Data Analysis of Yunnan Province Yunnan University

Using an effective adiabatic index γeffto mimic the feedback of efficient shock acceleration, we simulate the temporal evolution of a young type Ia supernova remnant （SNR） with two different background magnetic field（BMF） topologies:a uniform and a turbulent BMF. The density distribution and magnetic-field characteristics of our benchmark SNR are studied with two-dimensional cylindrical magnetohydrodynamic simulations. When γeffis considered, we find that:（1） the two-shock structure shrinks and the downstream magnetic-field orientation is dominated by the Rayleigh–Taylor instability structures;（2） there exists more quasi-radial magnetic fields inside the shocked region; and （3） inside the intershock region, both the quasi-radial magnetic energy density and the total magnetic energy density are enhanced:in the radial direction, with γeff=1.1, they are amplified about 10–26 times more than those with γeff=5/3. While in the angular direction, the total magnetic energy densities could be amplified about 350 times more than those with γeff=5/3, and there are more grid cells within the intershock region where the magnetic energy density is amplified by a factor greater than 100.

关键词： ISM: magnetic fields ISM: supernova remnants magnetohydrodynamics (MHD) methods: numerical

Research progress of slippage characteristic and gas film stability enhancement methods on biomimetic hydrophobic surfaces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第1期36卷 87-101页

作者： Meng-zhuo Zhang Hai-bao Hu Liu-zhen Ren Lu-yao bao Jun wen Luo Xie School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China

The biomimetic hydrophobic surface is a potentially efficient underwater drag reduction method and the drag reduction mechanism of this kind of surface comes from the interfacial slippage.For now,it is a hotspot to grasp the slippage characteristic and explore slippage enhancement strategies.This paper not only summarizes our numerical simulation and experimental results of slippage characteristic at the solid-liquid interface(SLI)of hydrophobic surfaces(HS)and the gas-liquid interface(GLI)of superhydrophobic surfaces(SHS)in recent years,but also introduces some innovative methods that can effectively improve the gas film stability and drag reduction effect of SHS.First,we used the molecular dynamics(MD)simulation method to figure out the effect of the solid-liquid interaction strength,the system temperature and the shear rate on the slippage of SLI,and expound their action mechanism from molecular scale.Then,by MD and multibody dissipative particle dynamics(MDPD)method,the slippage behavior at the GLI was studied under the influence of the microstructure size and the flow driving velocity.We proposed a new kind of hybrid slip boundary condition model to describe the slippage characteristic on GLI.In addition,we found through experiment that a three-dimensional backflow will appear on the GLI under the interfacial adsorption of surfactants,and the backflow direction will reverse with the change of GLI morphology.Finally,we put forward the wettability step structure and gas injection method to enhance the stability and drag reduction effect of the gas film on SHS.

关键词： Hydrophobic surface superhydrophobic surface interfacial slip underwater drag reduction

Critical Role of Ethylene-Propylene Block Copolymer in Impact Polypropylene Copolymer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-Hui Tang na Zhang Wei bao Wei Jiang Yuan Lin Zhao-Hui Su State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(EbP) is a vital component in impact polypropylene copolymer(IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IPCs were investigated by atomic force microscopy-infrared(AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer(EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-IR Ethylene-propylene block copolymers Core-shell rubber particles

Atroposelective Synthesis of 2-Arylindoles via Chiral Phosphoric Acid-Catalyzed Direct Amination of Indoles

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第7期42卷 731-735页

作者： wen bao Ye-Hui Chen Yu-Wei Liu Shao-Hua Xiang Bin Tan School of Pharmacy&StateKey Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhouGansu 730000China Shenzhen Grubbs Institute Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong 518055China

Indole-based atropisomers are a very important class of axially chiral compounds.However,the atroposelective synthesis of axially chiral 2-arylindole remains largely unexplored.In this study,we report the successful synthesis of atropisomeric 2-arylindoles using direct amination of indoles with p-quinonediimines in the presence of chiral phosphoric acid as a catalyst.Quinonediimine acts as an aminating reagent through formal polarity inversion of imine.The malonate group on the 2-aryl of 2-indoles was found to be essen-tial for high enantioselectivity of the products.This could be due to the additional interaction between the ester group and the cata-lyst,as well as the intramolecular hydrogen bonding.Our findings provide a new strategy for the asymmetric construction of 2-arylindole atropisomers.

关键词： Chiral phosphoric acid Quinonediimines Direct amination Nucleophilic addition Asymmetric catalysis Enantioselectivity Axially chiral 2-arylindole Atroposelective synthesis

Isorhamnetin Downregulates MMP2 and MMP9 to Inhibit Development of Rheumatoid Arthritis through SRC/ERK/CREB Pathway

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第4期30卷 299-310页

作者： LIU Xiao-rong LI Shuo-fu MEI wen-ya LIU Xiang-dan ZHOU Ri-bao College of Pharmacy Hunan University of Chinese MedicineChangsha(410208)China Department of Orthopaedics The First Hospital of Hunan University of Chinese MedicineChangsha(410007)China

Objective To investigate the effect of isorhamnetin on the pathology of rheumatoid arthritis(RA).Methods Tumor necrosis factor(TNF)-α-induced fibroblast-like synoviocytes(FLS)was exposed to additional isorhamnetin(10,20 and 40µmol/L).Overexpression vectors for matrix metalloproteinase-2(MMP2)or MMP9 or SRC were transfected to explore their roles in isorhamnetin-mediated RA-FLS function.RA-FLS viability,migration,and invasion were evaluated.Moreover,a collagen-induced arthritis(CIA)rat model was established.Rats were randomly divided to sham,CIA,low-,medium-,and high-dosage groups using a random number table(n=5 in each group)and administed with normal saline or additional isorhamnetin[2,10,and 20 mg/(kg·day)]for 4 weeks,respectively.Arthritis index was calculated and synovial tissue inflammation was determined in CIA rats.The levels of MMP2,MMP9,TNF-α,interleukin-6(IL-6),and IL-1β,as well as the phosphorylation levels of SRC,extracellular regulated kinase(ERK),and cyclic adenosine monophosphate response element-binding(CREB),were detected in RA-FLS and synovial tissue.Molecular docking was also used to analyze the binding of isorhamnetin to SRC.Results In in vitro studies,isorhamnetin inhibited RA-FLS viability,migration and invasion(P<0.05).Isorhamnetin downregulated the levels of MMP2,MMP9,TNF-α,IL-6,and IL-1βin RA-FLS(P<0.05).The overexpression of either MMP2 or MMP9 reversed isorhamnetin-inhibited RA-FLS migration and invasion,as well as the levels of TNF-α,IL-6,and IL-1β(P<0.05).Furthermore,isorhamnetin bound to SRC and reduced the phosphorylation of SRC,ERK,and CREB(P<0.05).SRC overexpression reversed the inhibitory effect of isorhamnetin on RA-FLS viability,migration and invasion,as well as the negative regulation of MMP2 and MMP9(P<0.05).In in vivo studies,isorhamnetin decreased arthritis index scores(P<0.05)and alleviated synovial inflammation.Isorhamnetin reduced the levels of MMP2,MMP9,TNF-α,IL-6,and IL-1β,as well as the phosphorylation of SRC,ERK,and CREB in synovial tissue(P<0.05).Notably,the inhibit

关键词： rheumatoid arthritis isorhamnetin SRC/ERK/CREB matrix metalloproteinase

Effects of NLRP3 Inflammasome Mediated Pyroptosis on Cardiovascular Diseases and Intervention Mechanism of Chinese Medicine

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第5期30卷 468-479页

作者： ZHONG Yi LI Xin-yue LIANG Tian-jun DING bao-zhu MA Ke-xin REN wen-xuan LIANG wen-jie College of Integrated Traditional Chinese and Western Medicine Hebei University of Chinese MedicineHebei Key Laboratory of Integrated Traditional Chinese and Western Medicine in Liver and Kidney DiseasesInstitute of Integrated Traditional Chinese and Western MedicineShijiazhuang 050200China Department of Cardiovascular Internal Medicine the Second Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi Province 332000China Graduate School Hebei Medical UniversityShijiazhuang 050017China Rural Physician College Hebei Medical UniversityShijazhuang 050017China Medical Department the First Hospital of Hebei Medical UniversityShijiazhuang 050030China

Activation of the NOD-like receptor protein 3(NLRP3)inflammasome signaling pathway is an important mechanism underlying myocardial pyroptosis and plays an important role in inflammatory damage to myocardial tissue in patients with cardiovascular diseases(CVDs),such as diabetic cardiomyopathy,ischemia/reperfusion injury,myocardial infarction,heart failure and hypertension.Noncoding Rnas(nc Rnas)are important regulatory factors.Many Chinese medicine(CM)compounds,including their effective components,can regulate pyroptosis and exert myocardium-protecting effects.The mechanisms underlying this protection include inhibition of inflammasome protein expression,Toll-like receptor 4–NF-κB signal pathway activation,oxidative stress,endoplasmic reticulum stress(ERS),and mixed lineage kinase 3 expression and the regulation of silent information regulator 1.The NLRP3 protein is an important regulatory target for CVD prevention and treatment with CM.Exploring the effects of the interventions mediated by CM and the related mechanisms provides new ideas and perspectives for CVD prevention and treatment.

关键词： pyroptosis cardiovascular diseases Chinese medicine NOD-like receptor protein 3 mechanisms

Exploration of pathogenic microorganism within the small intestine of necrotizing enterocolitis

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第2期20卷 165-172页

作者： Yan Wang Kun Jiang Qiao Xia Xia Kang Shan Wang Ji-Hong Yu wen-Feng Ni Xiao-Qin Qi Ying-na Zhang Jin-bao Han Gang Liu Lei Hou Zhi-Chun Feng Liu-Ming Huang Clinical Biobank Center Medical Innovation Research Division of ChinesePLA General HospitalBeijingChina Institute of Basic Medical Sciences Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Senior Department of Pediatrics The Seventh Medical Center of PLA General HospitalBeijing 100700China Department of Neurology The First Medical CenterChinese PLA General HospitalBeijing 100853China Department of Emergency Center National Center for Children's HealthBeijing Children's HospitalCapital Medical UniversityBeijing 100045China

Background Necrotizing enterocolitis(NEC)is the most common severe gastrointestinal emergency in neonates.We designed this study to identify the pathogenic microorganisms of NEC in the microbiota of the small intestine of neonates.Methods Using the 16S ribosomal Dna(rDna)sequencing method,we compared and analyzed the structure and diversity of microbiotas in the intestinal feces of different groups of neonates:patients undergoing jejunostomy to treat NEC(NP group),neonates undergoing jejunostomy to treat other conditions(NN group),and neonates with NEC undergoing conservative treatment(NC group).We took intestinal feces and saliva samples from patients at different time points.Results The beta diversities of the NP,NN,and NC groups were all similar.When comparing the beta diversities between different time points in the NP group,we found similar beta diversities at time points El to E3 but significant differences between the E2-E3 and E4 time points:the abundances of Klebsiella and Enterococcus(Proteobacteria)were higher at the E1-E3 time points;the abundance of Escherichia-Shigella(Proteobacteria)increased at the E2 time point,and the abundance of Klebsiella decreased significantly,whereas that of Streptococcus increased significantly at the E4 time point.Conclusions Our results suggest that the pathological changes of intestinal necrosis in the small intestine of infants with NEC are not directly caused by excessive proliferation of pathogenic bacteria in the small intestine.The sources of microbiota in the small intestine of neonates,especially in premature infants,may be affected by multiple factors.

关键词： Microbiota Necrotizing enterocolitis-Small intestine 16S rDna

Novel MIP gene mutation causes autosomal-dominant congenital cataract

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第3期17卷 454-465页

作者： Jing-Lan Ni Hua-Ming wen Xiao-Sheng Huang Qian-wen Li Jia-Min Cai bao-Jian Fan Jun Zhao The Second Clinical Medical College Jinan UniversityShenzhen 518020Guangdong ProvinceChina Department of Ophthalmology Dongguan Chang’an HospitalDongguan 523843Guangdong ProvinceChina Shenzhen Eye Hospital Affiliated to Jinan University Shenzhen Eye InstituteShenzhen 518040Guangdong ProvinceChina Department of Oral&Maxillofacial Surgery Shenzhen Stomatology Hospital Affiliated to Shenzhen UniversityShenzhen 518040Guangdong ProvinceChina Department of Neurosurgery Massachusetts General Hospital and Harvard Medical SchoolBoston 02114MassachusettsUSA Department of Ophthalmology Shenzhen People’s Hospital(the Second Clinical Medical CollegeJinan Universitythe First Affiliated HospitalSouthern University of Science and Technology)Shenzhen 518020Guangdong ProvinceChina

●AIM:To identify disease-causative mutations in families with congenital cataract.●METHODS:Two Chinese families with autosomaldominant congenital cataract(ADCC)were recruited and underwent comprehensive eye examinations.Gene panel next-generation sequencing of common pathogenic genes of congenital cataract was performed in the proband of each family.Sanger sequencing was used to valid the candidate gene mutations and sequence the other family members for co-segregation analysis.The effect of sequence changes on protein structure and function was predicted through bioinformatics analysis.Major intrinsic protein(MIP)-wildtype and MIP-G29R plasmids were constructed and microinjected into zebrafish single-cell stage embryos.Zebrafish embryonic lens phenotypes were screened using confocal microscopy.●RESULTS:A novel heterozygous mutation(c.85G>A;p.G29R)in the MIP gene was identified in the proband of one family.A known heterozygous mutation(c.97C>T;p.R33C;rs864309693)in MIP was found in the proband of another family.In-silico prediction indicated that the novel mutation might affect the MIP protein function.Zebrafish embryonic lens was uniformly transparent in both wild-type PCS2+MIP and mutant PCS2+MIP.●CONCLUSION:Two missense mutations in the MIP gene in Chinese cataract families are identified,and one of which is novel.These findings expand the genetic spectrum of MIP mutations associated with cataracts.The functional studies suggest that the novel MIP mutation might not be a gain-of-function but a loss-of-function mutation.

关键词： congenital cataract major intrinsic protein missense mutation zebrafish model