检索结果-南通市图书馆

维普期刊数据库

Three Gorges Dam: friend or foe of riverine greenhouse gases?

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第6期9卷 81-89页

作者： Jinren Ni Haizhen Wang Tao Ma Rong Huang philippe Ciais Zhe Li Yao Yue Jinfeng Chen Bin Li Yuchun Wang Maosheng Zheng Ting Wang Alistair G.L.Borthwick Key Laboratory for Water and Sediment Sciences Ministry of Education College of Environmental Sciences and Engineering Peking University State Environmental Protection Key Laboratory of All Materials Fluxes in River Ecosystems Ministry of Ecology and Environment Laboratoire des Sciences du Climat et de l'Environnement Institut Pierre Simon LaplaceCommissariat à l' énergie Atomique et aux énergies AlternativesCNRS Université de Versailles Saint-Quentinen-Yvelines Key Laboratory of Reservoir Environment Chongqing Institute of Green and Intelligent TechnologyChinese Academy of Sciences State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Water Environment China Institute of Water Resources and Hydropower Research MoE Key Laboratory of Regional Energy Systems optimization Resources and Environmental Research AcademyNorth China Electric Power University School of Engineering The University of Edinburgh

Dams are often regarded as greenhouse gas(GHG) emitters. However, our study indicated that the world’s largest dam, the Three Gorges Dam(TGD), has caused significant drops in annual average emissions of Co2, CH4and N2o over 4300 km along the Yangtze River, accompanied by remarkable reductions in the annual export of Co2(79%), CH4(50%) and N2o(9%) to the sea. Since the commencement of its operation in 2003, the TGD has altered the carbonate equilibrium in the reservoir area, enhanced methanogenesis in the upstream, and restrained methanogenesis and denitrification via modifying anoxic habitats through long-distance scouring in the downstream. These findings suggest that ‘large-dam effects’ are far beyond our previous understanding spatiotemporally, which highlights the fundamental importance of whole-system budgeting of GHGs under the profound impacts of huge dams.

关键词： Three Gorges Dam greenhouse gas spatiotemporal variation equilibrium Yangtze River whole system analysis

Modifications produced by selective inhibitors of cyclooxygenase and ultra low dose aspirin on platelet activity in portal hypertension

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2007年第38期13卷 5065-5070页

作者： Francisco X Eizayaga omar Aguejouf Vanessa Desplat philippe Belon Christian Doutremepuich CEBBAD Universidad Maimónides Buenos Aires Argentina France Laboratoire d'Hématologie Université Victor Segalen Bordeaux 2 Bordeaux 146 Rue Léo Saignat 33076 Bordeaux Cedex France Laboratoires Boiron Sainte-Foy-les-Lyons France

AIM: To study the mechanism involved in the potentially beneficial effect of ultra low dose aspirin (ULDA) in prehepatic portal hypertension, rats were pretreated with selective CoX 1 or 2 inhibitors (SC-560 or NS-398 respectively), and subsequently injected with ULDA or placebo. METHoDS: Portal hypertension was induced by portal vein ligation. Platelet activity was investigated with an in-vivo model of laser induced thrombus production in mesenteric circulation and induced hemorrhagic time (IHT). Platelet aggregation induced by ADP and dosing of prostanoid products 6-keto-PGF1α, TXB2, PGE2 and LTB4 were also performed. RESULTS: The portal hypertensive group receiving a placebo showed a decreased in vivo platelet activity with prolonged IHT, an effect that was normalized by ULDA. SC-560 induced a mild antithrombotic effect in the normal rats, and an unmodified effect of ULDA. NS-398 had a mild prothrombotic action in portal hypertensive rats, similar to ULDA, but inhibited a further effect when ULDA was added. An increased 6-keto-PGF1α was observed in portal hypertensive group that was normalised after ULDA administration. TXA2 level after ULDA, remained unchanged. CoNCLUSIoN: These results suggest that the effect of ULDA on platelet activity in portal hypertensive rats, could act through a CoX 2 pathway more than the CoX 1, predominant for aspirin at higher doses.

关键词： Ultra Low Dose Aspirin Portal hypertension CoX 1 CoX 2 CoX selective inhibition

Determination of N and o-Atoms, of N2(A) and N2(X, v >13) Metastable Molecules and N2+Ion Densities in the Afterglows of Ar-N2Microwave Discharges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Analytical Sciences, Methods and Instrumentation 2015年第4期5卷 59-65页

作者： Andre Ricard Hayat Zerrouki Jean-philippe Sarrette Laplace Toulouse France

Early afterglows of Ar-N2 flowing microwave discharges are characterized by optical emission spectroscopy. The N and o atoms, the N2(A) and N2(X, v > 13) metastable molecules and N2+ ion densities are determined by optical emission spectroscopy after calibration by No titration for N and o-atoms and measurements of No and N2 band intensities. For an Ar-xN2 gas mixture with × increasing from 2 to 100% at 4 Torr, 100 Watt and an afterglow time of 3 × 10- 3 s at the 5 liter reactor inlet, it is found densities in the ranges of (2 - 6) × 1014 cm- 3 for N-atoms, one order of magnitude lower for N2(X, v > 13) and for o-atoms (coming from air impurity), of 1010 - 1011 cm- 3 for N2(A) and of 108 - 109 cm- 3 for N2+.

关键词： Ar-N2 Microwave Discharge Flowing Afterglow N-Atoms N2 Metastables N2+ Ions

Relevance of Chest CT Scan Requests in Two University Teaching Hospitals in a Developing Country

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

open Journal of Radiology 2018年第2期8卷 84-90页

作者： Armel philippe Awana Ambroise Merci Seme Engoumou Julienne onguene Medza Patrice Esame Ndive odile Fernande Zeh Pierre ongolo Zogo Samuel Nko’o Amvene Yaounde Jamot Hospital Yaounde Cameroon Faculty of Medicine and Biomedical Sciences University of Yaounde I Yaounde Cameroon Vitro Fertilisation Yaounde Gynaecological Endoscopic Surgery and Human Reproductive Teaching Hospital Yaounde Came-roon Yaounde Gynaecology obstetrics and Pediatrics Hospital Yaounde Cameroon Yaounde Central Hospital Yaounde Cameroon Yaounde University Teaching Hospital Centre Yaounde Cameroon

Chest investigation is common in hospital practice. Chest X-ray is readily available and usually the first chest investigation. Thoracic CT scan constitutes an alternative and complimentary chest investigation. It is currently the most efficient investigation for the chest and its contents. objectives: To evaluate the relevance of chest CT Scan requests in two university teaching hospitals in Cameroon. Material and Methods: We conducted a cross-sectional, retrospective and descriptive study at the Radiology and imaging units of the Yaounde Central Hospital and the Yaounde University Teaching Hospital Centre. Included in our study were files of patients who had a chest CT scan investigation during three years. Results: We had a study population of 323 subjects. The age interval was 23 months to 91 years old. Pulmonologist were the most prescribers with 27.2%. We had 80% conformity of indications with French Society of Radiology (FSR) standards. 50 over of 323 indications were not recommended by the FSR. Conclusion: There is a conformity rate of 80% between indications and the FSR recommendations.

关键词： CT Scan Chest Relevance Request Prescribers

Paracetamol Sensitive Cellulose-Based Electrochemical Sensors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2018年第3期6卷 242-250页

作者： Maxime Pontie Serge Foukmeniok Mbokou Jean-philippe Bouchara Bienvenue Razafimandimby Sylvie Egloff ornella Dzilingomo Pierre-Yves Pontalier Ignas Kenfack Tonle Host-Pathogen Interaction Study Group(GEIHP EA 3142)UNIV AngersUNIV BrestBretagne Loire UniversityInstitute of Health Biology-IRISCHU4 rue Larrey49933 AngersFrance Electrochemistry and Chemistry of Materials Department of ChemistryUniversity of DschangP.O.Box 67 DschangCameroon Toulouse University INP-ENSIACETLCA(Laboratory of Agro-industrial Chemistry)31030 Toulouse France

Electrochemical determination of paracetamol(PCT)was successfully performed using carbon paste electrodes(CPEs)modified with treated coffee husks(CHt)or cellulose powder(Ce).Scanning electron microscopy was used to characterize unmodified or modified CPEs prior to their *** electrochemical oxidation of PCT was investigated using square wave voltammetry(SWV)and cyclic voltammetry(CV).The oxidation current density of PCT was two-fold higher with the CPE-CHt sensor and 30%higher with CPE-Ce in comparison with the unmodified CPE,and this correlated with the higher hydrophilicity of the modified *** SWV for the electrochemical analysis of PCT,carbon paste electrode modified with raw coffee husks(CPE-CHr)showed the presence of impurities at+0.27 V/SCE,showing the interest in using pure cellulose for the present analytical ***,CPE-Ce presented a higher real area compared to CPE-CHr,which explains the increase in the limit of saturation from 400 mg/L to 950 mg/*** better saturation limit exhibited by CPE-Ce justifies its choice for electroanalysis of PCT in commercialized *** proposed method was successfully applied in the determination of PCT in commercialized tablets(DolipraneR 500)with a recovery rate close to 100%,and no interference with the excipients contained in the tablets analyzed was *** novel sensor opens the way for sustainable development of electroanalytical control of drugs sold individually in developing countries.

关键词： Paracetamol carbon paste electrode coffee husks cellulose fibers square wave voltammetry electroanalysis

硅钨酸掺杂聚苯胺催化合成2-异丙基-1,3-二氧环戊烷

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

化学试剂 2007年第10期29卷 577-580,583页

作者：杨水金余协卿 philippe G.MERLE 湖北师范学院化学与环境工程系湖北黄石435002 Department of Chemistryand Biochemistry Concordia UniversityMontrealCanada

采用回流法自制了硅钨酸(H4SiW12o40)掺杂聚苯胺(PAn)催化剂H4SiW12o40/PAn。通过异丁醛和乙二醇为原料合成标题化合物,探讨了硅钨酸掺杂聚苯胺催化剂对缩醛反应的催化活性,较系统地研究了原料物质的量比、催化剂用量、反应时间诸因素... 详细信息

采用回流法自制了硅钨酸(H4SiW12o40)掺杂聚苯胺(PAn)催化剂H4SiW12o40/PAn。通过异丁醛和乙二醇为原料合成标题化合物,探讨了硅钨酸掺杂聚苯胺催化剂对缩醛反应的催化活性,较系统地研究了原料物质的量比、催化剂用量、反应时间诸因素对产率的影响。实验表明,硅钨酸掺杂聚苯胺催化剂是合成标题化合物的良好催化剂,在n(乙二醇)∶n(异丁醛)=1.5∶1,催化剂用量为反应物料总质量的1.2%,环己烷为带水剂,反应时间1.0h的优化条件下,标题化合物的收率可达88.8%。

关键词： 2-异丙基-1,3-二氧环戊烷硅钨酸聚苯胺催化缩醛反应

维普期刊数据库

Assessment of NH₃ Reduction and N₂o Production during Treatment of Exhausted Air from Fattening Pigs Building by a Commercial Scrubber

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences 2016年第10期7卷 693-709页

作者： Laurence Loyon philippe Dupard Patricia Saint-Cast Fabrice Guiziou Irstea UR OPAALE Rennes France Université Européenne de Bretagne Rennes France

The use of air scrubbers to reduce ammonia (NH3) emissions from buildings on pig farms is one of the most promising techniques in the GÖteborg protocol and other European regulations including the Industrial Emission Directive. In France, some air scrubbers are currently used on pig farms, mainly to reduce odours from livestock buildings. However, recent research revealed the production of N2o resulting from the treatment of air from pig buildings. In this context, a two-month study was conducted on a pig farm with 750 places for fattening pigs to check the abatement of NH3 emissions and to assess the possible production of N2o during treatment of exhausted air from buildings housing fattening pigs by a air scrubber. Concentrations of NH3 and N2o in the inlet and outlet air of the scrubber were continuously monitored using an Innova 1412 infrared analyzer. With the scrubber operating parameters (airflow, design, size), our results confirmed the production of N2o in the order of 5% of NH3-N reduced. N2o was produced by biological nitrification and/or denitrification inside the air scrubber. Statistical analysis (Pearson’s test) showed that the production of N2o was strongly influenced by the rate of airflow and the outside temperature. The abatement of NH3 emissions from the building was only 33%, i.e. much lower than the 70% - 90% usually cited in the literature.

关键词： Wet Scrubber Ammonia Nitrous oxide Piggery Air Treatment

Preparation, Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第3期17卷 293-298页

作者： Lianshe FU and Hongjie ZHANG Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China philippe Boutinaud Laboratoire des Materiaux Inorganiques, UMR 6002, Universite Univ Blaise Pascal Lab Mat Inorgan UMR 6002 F-63177 Clermont Ferrand France ENSCCF F-63177 Clermont Ferrand France Chinese Acad Sci Changchun Inst Appl Chem Key Lab Rare Earth Chem & Phys Changchun 130022 Peoples R China

Hybrid materials incorporating Eu-(TTA)(3). 2H(2)o (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.

关键词： MCM Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex Preparation

维普期刊数据库

A Bioenergetic-Redox Approach to the Effect of Live Yeast on Ruminal pH during Induced Acidosis in Dairy Cow

在线全文

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2013年第10期4卷 60-68页

作者： Jean philippe Marden Corine Bayourthe Eric Auclair Raymond Moncoulon Lesaffre Feed Additives Marquette-Lez-Lille France Université de Toulouse INPT ENSAT UMR1289 Tissus Animaux Nutrition Digestion Ecosystème et Métabolisme Castanet-Tolosan France INRA UMR1289 Tissus Animaux Nutrition Digestion Ecosystème et Métabolisme Castanet-Tolosan France Université de Toulouse INPT ENVT UMR1289 Tissus Animaux Nutrition Digestion Ecosystème et Métabolisme Toulouse France

The objective of this study was to evaluate the capacity of the live yeast (LY) Saccharomyces cerevisiae in optimizing ruminal pH and in understanding its mode of action during induced acidosis in dairy cow. Two non-lactating cannulated cows were used and offered twice daily a control diet (CD) consisting of 51% corn silage and 49% concentrates or a LY diet (LYD) composed of CD supplemented with 4 g of LY per cow and per day. Measurements of pH and redox potential (Eh) were continuously made at 1 h interval during an experimental period of 9 h per day. Samples of ruminal fluid were also taken at 2 h intervals for analyses of volatile fatty acids (VFA) and lactic acid. oxygen partial pressure (logPo2) in the ruminal milieu was calculated from the Nernst equation, using either o2-H2o or lactate-propionate redox couples. The results showed an increase of 0.2 unit in ruminal pH when LYD was fed, which was accompanied by a mean difference in Eh of -20 mV with respect to CD. The logPo2 decreased significantly by 0.8 log unit for LYD when compared to CD. Concentrations of VFA and proportion of propionate were higher with LYD (114.4 mM and 17.1% total VFA) compared to CD (102.4 mM and 15.4% total VFA). Proportion of butyrate decreased (from 15.8% to 14.2% total VFA). Lactate concentration decreased by 55% on average. It is proposed that the stabilization of ruminal pH (>6) is the outcome of the LY ability to scavenge oxygen. In doing so, it increased the reducing capacity of the milieu favoring the production of total VFA and depressing the level of lactate. The LY oxygen-scavenging ability was put forward to account for the transformation of lactate (pKa = 3.86) into propionate (pKa = 4.87) under reduced ruminal conditions.

关键词： Live Yeast oxygen Fugacity pH Redox Potential