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Comparison Between Catalytic Activity and Activity Changes During Denaturation by Guanidine Hydrochloride of Enzymes in Crystalline State and in solution

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Science China Chemistry 1993年第2期36卷 196-203页

作者：马永泽 State Key Laboratory of Biomacromolecules Institute of Biophysics Academia Sinica Beijing 100101 PRC College of Biological SciencesBeijing Agricultural UniversityBeijing 100094PRC

The catalytic activity and activity changes during denaturation by guanidine hydrochloride of glyceraldehyde-3-phosphate dehydrogenase,lactate dehydrogenase and α-chymotrypsin in crystalline state and in solution have been compared.The catalytic activities are lower in crystalline state than in solution. Enzymes in crystalline state are more stable than in solution during denaturation by guanidine hydrochloride.Ammonium sulfate has different effects on catalytic activities of different enzymes and shows protection on all enzymes studied during denaturation by guanidine hydrochloride.The protection is more obvious at high concentrations of guanidine hydrochloride than at low concentrations.It is suggested that the flexibility or mobility of enzyme is required for the catalytic activity and related to the stability of enzymes. Enzymes with less flexibility or mobility are more stable.

关键词： enzymes crystalline state solution state catalytic activity guanidine hydrochloride denaturation ammonium sulfate.

Long-term stability of gentamicin sulfate-ethylenediaminetetraacetic acid disodium salt (EDTA-Na_2) solution for catheter locks

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Journal of Pharmaceutical Analysis 2018年第6期8卷 386-393页

作者： Anne-Sophie Fiolet Elise Jandot Pauline Doucey Coralie Crétet Célia Brunel Christine Pivot Jean-Marc Ghigo Christophe Beloin David Lebeaux Fabrice Pirot Service Pharmaceutique Plateforme FRIPHARM Groupe Hospitalier Centre Edouard Herriot Hospices Civils de Lyon Unité de Génétique des Biofilms Département de Microbiologie Institut Pasteur Service de Microbiologie Unité Mobile de Microbiologie Clinique Assistance Publique-H?pitaux de Paris H?pital Européen Georges Pompidou Université Paris Descartes 12 rue de l'Ecole de Médecine Laboratoire de Recherche et Développement de Pharmacie Galénique Industrielle UMR 5305 Plateforme FRIPHARMF-69373 Faculté de Pharmacie Université Claude Bernard Lyon 1 8 avenue Rockefeller

A lock solution composed of gentamicin sulfate(5 mg/mL) and ethylenediaminetetraacetic acid disodium salt(EDTA-Na2, 30 mg/mL) could fully eradicate in vivo bacterial biofilms in totally implantable venous access ports(TIVAP). In this study, fabrication, conditioning and sterilization processes of antimicrobial lock solution(ALS) were detailed and completed by a stability study. Stability of ALS was conducted for12 months in vial(25 °C 7 2 °C, 60% 7 5% relative humidity(RH), and at 40 °C 7 2 °C, RH 75% 7 5%)and for 24 h and 72 h in TIVAP(40 °C 7 2 °C, RH 75% 7 5%). A stability indicating HPLC assay with UV detection for simultaneous quantification of gentamicin sulfate and EDTA-Na2 was developed. ALS was assayed by ion-pairing high performance liquid chromatography(HPLC) needing gentamicin derivatization, EDTA-Na2 metallocomplexation of samples and gradient mobile phase. HPLC methods to separate four gentamicin components and EDTA-Na2 were validated. Efficiency of sterility procedure and conditioning of ALS was confirmed by bacterial endotoxins and sterility tests. Physicochemical stability of ALS was determined by visual inspection, osmolality, pH, and sub-visible particle counting. Results confirmed that the stability of ALS in vials was maintained for 12 months and 24 h and 72 h in TIVAP.

关键词： Gentamicin-EDTA-Na2 loaded antimicrobial lock solution Pharmaceutical compounding Stability indicating HPLC assay method Totally implantable venous access ports

solution and Diffusion Behavior of Pure Gases and Gas Mixtures in Glassy Polymer Membranes

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Science China Chemistry 1994年第5期37卷 522-530页

作者：庄震万卫伟时钧 Nanjing Institute of Chemical Technology Nanjing 210009 PRC

A general model for the solution and diffusion behavior in pure gas-polymer membrane systems and gas mixture-polymer membrane systems has been developed. Proved by experiments on different glassy and rubbery polymer membranes at various temperatures and pressures, this model can achieve the prediction of permeation behavior of pure gases and gas mixtures in polymer membranes only using the model parameters obtained from experiments on pure gases. The calculated results are in good agreement with experimental.

关键词： gas permeation polymer membrane solution and diffusion transport mechanism.

Redefining the properties of an osmotic agent in an intestinal-specific preservation solution

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World Journal of Gastroenterology 2010年第45期16卷 5701-5709页

作者： Kimberly Schlachter Matthew S Kokotilo Jodi Carter Aducio Thiesen Angela Ochs Rachel G Khadaroo Thomas A Churchill Department of Surgery University of AlbertaEdmontonAlbertaT6G2B7Canada Department of Laboratory Medicine and Pathology University of AlbertaEdmontonAlbertaT6G2B7Canada

AIM: To investigate the effects of dextrans of various molecular weights (Mw) during a 12 h cold storage time-course on energetics, histology and mucosal infiltration of fluorescein isothiocyanate (FITC)-dextran. METHODS: Rodent intestines were isolated and received a standard University of Wisconsin vascular flush followed by intraluminal administration of a nutrientrich preservation solution containing dextrans of varying Mw: Group D1, 73 kdal; Group D2, 276 kdal; Group D3, 534 kdal; Group D4, 1185 kdal; Group D5, 2400 kdal. RESULTS: Using FITC-labeled dextrans, fluorescent micrographs demonstrated varying degrees of mucosal infiltration; lower Mw (groups D1-D3: 73-534 kdal) dextrans penetrated the mucosa as early as 2 h, whereas the largest dextran (D5: 2400 kdal) remained captive within the lumen and exhibited no permeability even after 12 h. After 12 h, median injury grades ranged from 6.5 to 7.5 in groups D1-D4 (73-1185 kdal) representing injury of the regenerative cryptal regions and submucosa; this was in contrast to group D5 (2400 kdal) which exhibited villus denudation (with intact crypts) corresponding to a median injury grade of 4 (P 2400 kdal act as true impermeant agents during 12 h ischemic storage when incorporated into an intraluminal preservation solution.

关键词： Intraluminal preservation solution Intestinal-specific Osmotic impermeant Organ preservation Cold storage

Insulin like growth factor-1 increases fatty liver preservation in IGL-1 solution

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World Journal of Gastroenterology 2010年第45期16卷 5693-5700页

作者： Mohamed Amine Zaouali Susagna Padrissa-Altés Ismail Ben Mosbah Hassen Ben Abdennebi Olivier Boillot Antoni Rimola Dalila Saidane-Mosbahi Joan Roselló-Catafau Experimental Hepatic Ischemia-Reperfusion Unit Institut d'Investigacions Biomèdiques de BarcelonaConsejo Superior de Investigaciones Científicas08036 BarcelonaSpain Unitat de Transplantament de Fetgei Viabilitat del' Empelt Institut d'Investigacions Biomèdiques August Pii Sunyer08036 BarcelonaSpain Laboratory of Human Physiology Faculty of PharmacyUniversity of Monastir5000 MonastirTunisia Unit of Hepatic Transplantation Edouard Herriot Hospital69003 LyonFrance Biomedical Research Center Esther Koplowitz CIBER-ehdInstitute of Health Carlos Ⅲ08036 BarcelonaSpain

AIM: To investigate the benefits of insulin like growth factor-1 (IGF-1) supplementation to serum-free institut georges lopez-1 (IGL-1) solution to protect fatty liver against cold ischemia reperfusion injury. METHODS: Steatotic livers were preserved for 24 h in IGL-1  solution supplemented with or without IGF-1 and then perfused "ex vivo " for 2 h at 37℃. We examined the effects of IGF-1 on hepatic damage and function (transaminases, percentage of sulfobromophthalein clearance in bile and vascular resistance). We also studied other factors associated with the poor tolerance of fatty livers to cold ischemia reperfusion injury such as mitochondrial damage, oxidative stress, nitric oxide, tumor necrosis factor-α (TNF-α) and mitogen-activated protein kinases.RESULTS: Steatotic livers preserved in IGL-1 solutionsupplemented with IGF-1 showed lower transaminase levels, increased bile clearance and a reduction in vascular resistance when compared to those preserved in IGL-1solution alone. These benefits are mediated by activation of AKT and constitutive endothelial nitric oxide synthase (eNOS), as well as the inhibition of inflammatory cytokines such as TNF-α. Mitochondrial damage and oxidative stress were also prevented.CONCLUSION: IGL-1  enrichment with IGF-1 increasedfatty liver graft preservation through AKT and eNOS activation, and prevented TNF-α release during normothermic reperfusion.

关键词： AKT Institut georges lopez-1 solution Insulin like growth factor-1 Ischemia reperfusion injury Nitric oxide Oxidative stress Steatotic graft preservation

Nanopore sequencing: a rapid solution for infectious disease epidemics

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Science China(Life Sciences) 2019年第8期62卷 1101-1103页

作者： Ying Cao Jing Li Xin Chu Haizhou Liu Wenjun Liu Di Liu Center for Emerging Infectious Diseases Wuhan Institute of VirologyChinese Academy of SciencesWuhan430071China Research Group of Computer Virology Center for Bacteria and Virus Resources and ApplicationWuhan Institute of VirologyChineseAcademy of SciencesWuhan430071China Institute of Microbiology Chinese Academy of SciencesBeijing100101China Bureau of Major R&D Programs Chinese Academy of SciencesBeijing100864China University of Chinese Academy of Sciences Beijing100049China

Emerging and re-emerging infectious diseases have given rise to a large number of human infections,morbidity,and heavy economic burden,including the Middle East respiratory syndrome caused by a coronavirus in 2012,global influenza pandemic caused by the H7N9 influenza A virus in2013,Ebola epidemic in West Africa in 2014,and Lassa fever epidemic in Nigeria in 2019.The healthcare war against viruses deserves constant surveillance due to the continuous emergence of new viruses and rapid evolution of existing viruses(Liu and Liu,2017).

关键词： pro RNA Nanopore sequencing a rapid solution for infectious disease epidemics

A simple method for solving unidirectional methane gas flow in coal seam based on similarity solution

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International Journal of Mining Science and Technology 2018年第2期28卷 331-334页

作者： Zhou Yan Meng Qian Lin Baiquan Qin Jilong Zhou Guiping Key Laboratory of Gas and Fire Control for Coal Mines (China University of Mining & Technology) Ministry of Education School of Computer Science and Technology Jiangsu Normal University

The equation used to model the unidirectional flow of methane gas in coal seams is usually formulated as a nonlinear partial differential equation, which needs to be solved numerically with a computer program.Nevertheless, for people without access to the computer program, the conventional numerical method may be inconvenient. Thus, the objective here is to seek some method simpler than the conventional one for solving the flow problem. A commonly used model of the unidirectional methane gas flow is considered, where the methane adsorption is described by the Langmuir isotherm and the free gas is treated as real gas. By introducing the similarity solution, a simple method for solving the flow model is proposed, which can be done on a hand calculator. It is shown by two examples that the gas pressure profile obtained by the proposed method agrees well with the direct numerical solution of the flow model.

关键词： Coalbed methane Migration Unidirectional flow Similarity solution Simplified solving Numerical method

Correlation of microstructure and magnetic properties in Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets solution-treated at different temperatures

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Rare Metals 2019年第1期38卷 20-28页

作者： Cheng Xu Hui Wang Tian-Li Zhang Alexander Popov Raghavan Gopalan Cheng-Bao Jiang School of Materials Science and Engineering Beihang University M.N. Miheev Institute of Metal Physics Ural Branch of Russian Academy of Sciences International Advanced Research Centre for Powder Metallurgy and New Materials(ARCI) IITM Research Park

The correlation of microstructure and magnetic properties in Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets solution-treated at different temperatures was systematically investigated. It is found that the magnets solution-treated at 1219℃ possess a single 1:7 H phase, exhibiting the homogeneous cellular structure during further aging treatment, leading to the optimum magnetic properties. However, for the magnets solution-treated at 1211 and 1223℃,2:17 H or 1:5 H secondary phase will also form besides 1:7 H main phase, which cannot transform into cellular structure,thus deteriorating the magnetic properties greatly. The irreversible magnetization investigations with recoil loops also propose a non-uniform pinning in the magnets induced by the secondary precipitates. At proper solution temperature, Zr is supposed to occupy the Fe-Fe dumbbell sites in the form of Zr-vacancy pairs, leading to the minimum c/a ratio and thus stabilizing the 1:7 H phase. Finally,Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets with the maximum energy product and intrinsic coercivity at 550℃ up to 60.73 kJ·m^(-3) and 553.88 kA·m^(-1) were prepared by powder metallurgy method.

关键词： Sm2Co17 solution treatment Phase constitution Demagnetization curve squareness

Thermophysical properties of solution precursor plasma-sprayed La2Ce2O7 thermal barrier coatings

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Rare Metals 2019年第7期38卷 689-694页

作者： Bei-Bei Feng Yi Wang Qiang Jia Wei Huang Hong-Li Suo Wen Ma School of Materials Science and Engineering Beijing University of Technology Beijing 100022 China The Key Laboratory of Advanced Functional Materials Ministry of Education of China Beijing University of Technology Beijing 100022 China School of Materials Science and Engineering Inner Mongolia University of Technology Huhhot 010051. China

La2Ce2O7 (LCO) is a promising candidate for thermal barrier coatings (TBCs) due to that it provides better thermal insulation than yttria-stabilized zirconia (YSZ) does. In this work, a TBC LCO was produced by solution precursor plasma spraying (SPPS). After the solution precursors were prepared and the spraying parameters were optimized, the thermophysical properties and thermal shock performance of the coatings were tested. It was found that the SPPS coating with segmentation crack density of 6 mm^-1 had the porosities of about 33.5% at spray distances of 35 mm. The thermal conductivity of the SPPS coatings is 0.50-0.75 W·m^-1·K^-1, much lower than that of the atmospheric plasma spraying (APS) coatings (0.85-1.25 W·m^-1·K^-1). The thermal shock performance of the SPPS coatings reached 60 cycles, much better than the APS coatings. This improvement is due to the segmentation cracks in the coatings, which can improve strain tolerance and effectively relieve internal stress. This study provides reference significance for further research on thermal barrier coatings.

关键词： La2Ce2O7 solution precursor plasma spraying Thermal conductivity Segmentation cracks