检索结果-南通市图书馆

Cloning, expression and biocharacterization of OfCht5, the chitinase from the insect Ostrinia furnacalis

Insect Science 2013年第2期20卷 147-157页

作者： qingyue Wu tian liu qing Yang Department of Bioscience and Biotechnology Dalian University of Technology Dafian China

Chitinase catalyzes β,4-glycosidic linkages in chitin and has attracted re- search interest due to it being a potential pesticide target and an enzymatic tool for preparation of N-acetyl-β D-glucosamine. An individual insect contains multiple genes encoding chitinases, which vary in domain architectures, expression patterns, physiological roles and biochemical properties. Herein, Of ChtS, the glycoside hydrolase family 18 chiti- nase from the widespread lepidopteran pest Ostrinia furnacalis, was cloned, expressed in the yeast Pichia pastoris and biochemically characterized in an attempt to facilitate both pest control and biomaterial preparation. Complementary DNA sequence analysis indicated that Of CHT5 consisted of an open reading frame of 1 665-bp nucleotides. Phy- logenic analysis suggested Of Cht5 belongs to the Group I insect chitinases. Expression of Of Cht5 in Pichia pastoris resulted in highest specific activity after 120 h of induction with methanol. Through two steps of purification, consisting of ammonium sulfate pre- cipitation and metal chelating chromatography, about 7 mg of the recombinant Of Cht5 was purified to homogeneity from 1 L culture supernatant. Of Cht5 effectively converted colloidal chitin into chitobiose, but had relatively low activity toward a-chitin. When chi- tooligosaccharides [（GlcNAc）n, n = 3-6] were used as substrates, Of Cht5 was observed to possess the highest catalytic efficiency parameter toward （GlcNAc）4 and predominan- tely hydrolyzed the second glycosidic bond from the non-reducing end. Together with fl-N-acetyl-D-hexosaminidase OfHexl, Of Cht5 achieved its highest efficiency in chitin degradation that yielded N-acetyl-β D-glucosamine, a valuable pharmacological reagent and food supplement, within a molar concentration ratio of Of Cht5 versus Of Hexl in the range of 9 ： 1-15 ： 1. This work provides an alternative to existing preparation of chitinase for pesticides and other applications.

关键词： chitin chitinase glycoside hydrolase N-acetyl-β-D-glucosamine Ostriniafurnacalis pest control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Simulation of Microcarrier Motion in a Rotating Wall Vessel Bioreactor

引用

Biomedical and Environmental Sciences 2006年第3期19卷 163-168页

作者： ZHI-HAO JU tian-qing liu XUE-Hu MA ZHAN-FENG CUI State Key Laboratory of Fine Chemical Engineering Stem Cells ＆ Tissue Engineering Laboratory Dalian University of Technology Dalian 116012 Liaoning China Department of Engineering Science Oxford University Oxford OX1 3PJ UK

Objective To analyze the forces of rotational wall vessel （RWV） bioreactor on small tissue pieces or microcarrier particles and to determine the tracks of microcarrier particles in RWV bioreactor. Methods The motion of the microcarrier in the rotating wall vessel （RWV） bioreactor with both the inner and outer cylinders rotating was modeled by numerical simulation. Results The continuous trajectory of microcarrier particles, including the possible collision with the wall was obtained. An expression between the minimum rotational speed difference of the inner and outer cylinders and the microcarrier particle or aggregate radius could avoid collisions with either wall. The range of microcarrier radius or tissue size, which could be safely cultured in the RWV bioreactor, in terms of shear stress level, was determined. Conclusion The model works well in describing the trajectory of a heavier microcarrier particle in rotating wall vessel.

关键词： Tissue engineering Bioreactor Rotating wall vessel Numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence characteristics of water penetration on fibre-reinforced polymer/rigid polyurethane foam interface of the composite cross-arm considering natural ageing

引用

High Voltage 2024年第1期9卷 81-93页

作者： Jun Xie Zhe Zhou Ziqian liu Haonan tian Sigang Zhang qing Xie Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina State Grid Gansu Electric Power Company LanzhouChina

Fibre-reinforced polymer(FRP)/rigid polyurethane foam(RPUF)interface is susceptible to moisture intrusion in addition to natural ageing during *** study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics(MD)*** absorption,shear strength,and leakage current tests were used to clarify the changes in the interface *** degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and *** results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the *** addition,water mainly invades the interface through *** water penetration,the interfacial bonding strength and insulation performance significantly *** and hydrolysis of interfacial materials are the main reasons for decreased interfacial *** can cause irreversible damage to the interface,increasing interface defects and water *** vicious cycle of material hydrolysis is the ultimate cause of interfacial *** polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

关键词： interface polyurethane interfacial

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Production of β-1,3-glucanase and chitinase of two biocon-trol agents and their possible modes of action

引用

Chinese Science Bulletin 2002年第4期47卷 292-296页

作者： FAN qing, tian Shiping, liu Haibo & XU YongInstitute of Botany, Chinese Academy of Sciences, Beijing 100093, China Institute of Botany Chinese Academy of Sciences Beijing China

Pichia membranefaciens Hansen and Candida guilliermondii (Cast) Langeronet Guerra are two antagonists of R. stolonifer on harvested nectarine and peach fruits. In this study, β-1,3-glucanase and chitinase activities of the antagonists were induced in vitro and in vivo. The highest β-1, 3-glucanase activity was detected in Lilly-Barnett minimal salt medium supplemented with glucose in combination with CWP of R. stolonifer as a carbon source. The β-1,3-glucanase activity of P. membranefaciens reached the maximum level, being 114.0 SU (specific activity unit), and that of C. guilliermondii reached 103.2 SU. The lowest β-1,3-glucanase activity was observed in the medium containing glucose as sole car-bon source. P. membranefaciens was able to produce signifi-cantly higher levels of chitinase (exochitinase and endochiti-nase) in vitro than C. guilliermondii grown in Czapeck mini-mal medium. An increase in β-1,3-glucanase and chitinase activity was also triggered by wounding, adding of carbon sources

关键词： biological control yeast rhizopus rot β-1 3-glucanase chitinase.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Immunohistochemical analysis of PD-L1 and tumor-infiltrating immune cells expression in the tumor microenvironment of primary signet ring cell carcinoma of the prostate

引用

Asian Journal of Andrology 2022年第5期24卷 525-532页

作者： Qi-Liang Teng Xin-Rui Yang Shuang Wen Zhi-Hong Dai Hong-Long Wang tian-qing liu Liang Wang Bo Fan Zhi-Yu liu Department of Urology Second Affiliated Hospital of Dalian Medical UniversityDalian 116023China Department of Clinical Imaging Second Affiliated Hospital of Dalian Medical UniversityDalian 116023China Department of Pathology Dalian Friendship HospitalDalian 116001China

Primary signet ring cell carcinoma(SRCC)of the prostate is a rare ***,its potential tumorigenic mechanism,clinicopathological features,and prognostic outcome have not been systematically *** determine the pathogenic mechanism,we detected distributions of programmed cell death-ligand 1(PD-L1),programmed death 1(PD-1),and cellular components in the tumor microenvironment,including tumor-infiltrating lymphocytes(CD4 and CD8),tumor-associated macrophages(TAMs;CD163 and CD68),and tumor-associated fibroblasts(vimentin and alpha-smooth muscle actin[α-SMA]),in tumor tissues from four patients with primary prostatic SRCC compared with corresponding adjacent tissues and tumor tissues from 30 patients with prostate adenocarcinoma(PCa)by immunohistochemical *** found higher expression of PD-L1,CD163,and CD68 in primary SRCC specimens than that in both corresponding adjacent nontumor specimens and PCa specimens with different Gleason scores,indicating that TAMs may participate in the malignant biological behavior of primary SRCC of the *** further analysis,we searched electronic journal databases and Surveillance,Epidemiology,and End Results(SEER)to identify 200 eligible patients including our four *** to Kaplan–Meier survival curve analysis,patients<68 years old,with radical prostatectomy(RP),Gleason score of 7–8,and lower clinical stage had longer overall survival(OS).Moreover,Cox multivariate analysis indicated that race(hazard ratio[HR]=1.422),surgical approach(HR=1.654),and Gleason score(HR=2.162)were independent prognostic factors for ***,primary SRCC of the prostate represents a distinct and aggressive subtype of prostate cancer associated with a higher distribution of PD-L1 and TAMs,which warrants further clinical investigation.

关键词： clinical features immunohistochemistry infiltrating immune cells primary signet ring cell carcinoma of the prostate tumor microenvironment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The effects of various factors on spontaneous imbibition in tight oil reservoirs

引用

Petroleum Science 2024年第1期21卷 315-326页

作者： Cheng liu tian-Ru Wang qing You Yue-Chun Du Guang Zhao Cai-Li Dai School of Energy Resources China University of GeosciencesBeijing100083PR China School of Petroleum Engineering China University of PetroleumQingdao266580ShandongPR China

Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.

关键词： Tight oil reservoir Spontaneous imbibition Nuclear magnetic resonance Slickwater fracturing fluid Fluid utilization degree

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Phase transfer-based high-efficiency recycling of precious metal electrocatalysts

引用

Green Chemical Engineering 2024年第1期5卷 68-74页

作者： qing Zeng Shaonan tian Yu Zhang Hui liu Dong Chen Xinlong tian Chaoquan Hu Jun Yang State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Lab of Fine ChemistrySchool of Chemical Engineering and TechnologyHainan UniversityHaikou570228China Nanjing IPE Institute of Green Manufacturing Industry Nanjing211100China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China

Recycling precious metals with high-efficiency is undoubtedly beneficial to optimize resource utilization for environmental remediation and sustainable ***,we report an efficient route to recycle the palladium(Pd)and platinum(Pt)electrocatalysts using a phase transfer *** strategy involves acidic dissolution of deactivated precious metal(Pd/Pt)electrocatalysts from their loading substrates,mixing with an ethanolic solution of dodecylamine(DDA),subsequent extraction of metal ions into a non-polar organic phase,and final reduction by sodium borohydride to reproduce high-performance electrocatalysts towards typical electrochemical reactions,e.g.,oxygen reduction reaction(ORR)and ethanol oxidation reaction(EOR).In specific,the transfer efficiencies are up to 98%and the final recovery rate is over 85%for Pd and Pt electrocatalysts in each *** approach symbolizes a facile and efficient way to recover precious metals,which might be applied to recycling a wide range of metals in various realms after appropriate modifications.

关键词： Precious metal Phase transfer Extraction Recovery Electrocatalyst

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Biomimetic microchannel network with functional endothelium formed by sacrificial electrospun fibers inside 3D gelatin methacryloyl(GelMA)hydrogel models

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 79-96页

作者： Haoyu SUN Haiyang MA Li WANG Yang liu tian HOU Wenjie TANG qing YU Meiwen AN Meiling WEN Institute of Biomedical Engineering College of Biomedical EngineeringTaiyuan University of TechnologyTaiyuan030024China

Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular *** report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network,using electrospinning techniques and the sacrificial template method for 3D cell *** and cavities were created within the gelatin methacryloyl(GelMA)hydrogel by sacrificing polyvinyl alcohol(PVA)electrospun fibers(>10µm),resulting in the creation of microvessel-like *** characterizations,swelling properties,and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture *** to pure GelMA hydrogel,the hydrogel with microchannels promoted cell proliferation,adhesion,and endothelial tube ***,the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells(HUVECs)and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.

关键词： Biomimetic scaffold Photocrosslinking Microchannel network Tissue engineering Artificial microvascular

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Sand control mechanism of radial well filled with phase change material in hydrate reservoir

引用

Petroleum Science 2024年第4期21卷 2571-2582页

作者： Xiao-Qiang liu Zhong-Xi Han Zhi-Lin Luo Hai-Long Lu Ying Sun qing You tian-Kui Guo Zhan-qing Qu School of Energy Resources China University of Geosciences (Beijing) Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering China University of Geosciences (Beijing) China Research Institute of Petroleum Exploration and Development Engineering Technology Research Institute of Southwest Oil & Gas Field Company PetroChina Beijing International Center for Gas Hydrate School of Earth and Space Sciences Peking University School of Advanced Material Peking University Shenzhen Graduate School School of Petroleum Engineering China University of Petroleum (East China)

Radial well filled with phase change material has been proposed as a novel sand control method for hydrate exploitation. In order to reveal the sand control mechanism, CFD-DEM coupling method is applied to simulate the migration, settlement, and blockage processes of sand particles in the radial *** obtained results indicate that three scenarios have been recognized for sand particles passing through sand control medium, based on the diameter ratio of sand control medium to sand particle（Dd）:fully passing（Dd= 8.75-22.5）, partially passing and partially blocked（Dd= 3.18-5.63）, and completely blocked（Dd= 2.18-3.21）. After being captured by the sand control medium, sand particles can block pores, which increases fluid flow resistance and causes a certain pressure difference in the radial *** pressure in the radial well should be lower than the hydrate phase equilibrium pressure during sand control design, for the purpose of promoting hydrate decomposition, and sand capture. The length of the radial well should be optimized based on the reservoir pore pressure, production pressure difference,bottom hole pressure, and the pressure gradient in the radial well. It should be noticed that the sand control medium leads to a decrease in permeability after sand particles captured. Even the permeability is reduced to several hundred millidarcy, it is still sufficient to ensure the effective flow of gas and water after hydrate decomposition. Increasing fluid velocity reduces the blocking capacity of the sand control medium, mainly because of deterioration in bridging between sand particles.

关键词： Hydrate reservoir Sand control Radial well CFD-DEM

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Preoperative blood markers and intra-abdominal infection after colorectal cancer resection

引用

World Journal of Gastrointestinal Surgery 2024年第2期16卷 451-462页

作者： Chang-qing liu Zhong-Bei Yu Jin-Xian Gan tian-Ming Mei Department of Gastrointestinal Anorectal Surgery Suzhou Hospital Affiliated to Anhui Medical UniversitySuzhou 234000Anhui ProvinceChina

BACKGROUND Colorectal cancer(CRC)has one of the highest morbidity and mortality rates among digestive tract ***-abdominal infection(IAI)is a common postoperative complication that affects the clinical outcomes of patients with CRC and hinders their rehabilitation ***,the factors influencing abdominal infection after CRC surgery remain unclear;further,prediction models are rarely used to analyze preoperative laboratory indicators and postoperative *** To explore the predictive value of preoperative blood markers for IAI after radical resection of *** The data of 80 patients who underwent radical resection of CRC in the Anorectal Surgery Department of Suzhou Hospital affiliated with Anhui Medical University were *** patients were categorized into IAI(n=15)and non-IAI groups(n=65)based on whether IAI *** factors were compared;general data and laboratory indices of both groups were *** relationship between the indicators was ***,a nomogram prediction model was developed and evaluated;its utility and clinical applic-ability were *** The risk factors for IAI after radical resection of CRC were neutrophil-lymphocyte ratio(NLR),platelet-lymphocyte ratio(PLR),systemic immune-inflammation index(SII),and carcinoembryonic antigen(CEA)*** was correlated with PLR and SII(r=0.604,0.925,and 0.305,respectively),while PLR was correlated with SII(r=0.787).The nomogram prediction model demonstrated an area under the curve of 0.968[95%confidence interval(CI):0.948-0.988]in the training set(n=60)and 0.926(95%CI:0.906-0.980)in the validation set(n=20).The average absolute errors of the calibration curves for the training and validation sets were 0.032 and 0.048,respectively,indicating a good model *** decision curve analysis curves demonstrated high net income above the 5%threshold,indicating the clinical practicality of the *** The nomogram model constructed

关键词： Radical resection of colorectal cancer Inflammatory factors Intra-abdominal infection Predictive model Blood markers

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：