检索结果-南通市图书馆

Evaluation of Potential Extracts Antioxydant (Aqueous, Hydro-ethanolic and ethanolic) of an Aquatic Plant from the River djoue (<i>Ledermanniella schlechteri</i>)

引用

Open Journal of Applied sciences 2021年第3期11卷 254-263页

作者： Roniche Nguie Tsiba Gouollaly Arnaud W. G. Tamba Sompila J. E. Moussounga M. Gadet dzondo N. P. G. Pambou-Tobi P. diakabana Reyes H. Gampoula Centre de Recherche et d’Initiation des Projets de technologie cité scientifique route de l’auberge de Gascogne Brazzaville Congo EPRAN-Congo P&#244 le d’Excellence en Alimentation et Nutrition Faculté des Sciences et Techniques Université Marien NGOUABI Brazzaville Congo Institut national de Recherche en sciences de la Santé cité scientifique route de l’auberge de Gascogne Brazzaville Congo Unité de Chimie du Végétal et de la Vie FST-UMNG Brazzaville Congo laboratoire de Bioprocédés alimentaires et médicaux ENSP-UMNG Brazzaville Congo Ecole Nationale Supérieure Polytechnique (ENSP) Université Marien NGOUABI (UMNG) Brazzaville Congo Ecole Supérieure de technologie des Cataractes Brazzaville Congo

The aim for this present study was to evaluate the antioxidant potential of aqueous extracts (AE), hydro-ethanolic extracts (HE) and ethanolic extracts (EE) obtained from an aquatic plant (L. schlechteri) using a simple and fast method that is the CCM. This method revealed the presence of phenolics and flavonoids at different levels but with higher antioxidant activity in EE compared to AE. Among the two families of antioxidants evaluated, the phenolic compounds were found to be higher on the EE (5.85 mgEAG/MS) followed by the HE (5.06 mgEAG/MS) and less and less important on the AE (3.661 mgEAG/MS). While the less significantly elevated flavonoids showed values of 1.146 mgECa/MS for EE, 0.406 mgECa/MS for HE et 0.181 mgECa/MS for AE. However, the anti-free radical activity was also evaluated. Unlike the antioxidant activity, the ant-free radical activity with a greater IC50 was observed on AE with a rate of 66.66 mg/mL, then less on the hydro-ethanolic and ethanolic extracts, respectively at levels of 26.15 mg/mL et 19.18 mg/mL.

关键词： Evaluation Antioxidant Potential Extracts Aquatic Plant Ledermanniella schlechteri

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

Application of Neural Networks for Monitoring Mechanical defects of Rotating Machines

引用

Journal of Energy and Power Engineering 2012年第2期6卷 276-282页

作者： Ziane derouiche mohamed Boukhobza Benyebka Belmekki Jean Michel Rouvaen department of Electronic UniversitJ des Sciences et de la Tecnologie Oran 31000 Algeria Opto-Acousto-Electronic laboratory University of Valenciennes Valenciennes Cedex 59304 France

Good monitoring of the deterioration in rotating machinery can result in reduced maintenance costs by minimizing the loss of production due to the number of machine breakdown and decreasing in the number of spare parts. In the present paper, a prognostic method based on recurrent neural networks is applied to forecast the rate of machine deterioration. Promising results have been obtained through the application of this method to the prediction of vibration based fault trends of an auxiliary gearbox of a power generation plant. This method evaluates also the seriousness of damage caused by faults.

关键词： Maintenance prediction vibration artificial neurons networks.

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

Synthesis and Antibacterial Activities of New 2-(Benzylthio)pyrimidines and 2-(Benzimidazolylmethylthio)pyrimidines derivatives

引用

Open Journal of Medicinal Chemistry 2021年第3期11卷 27-39页

作者： Achi Patrick-Armand Coulibali Siomenan Zon doumade Timotou Adéyolé Bolou Eric Touré daouda Sissouma drissa Adjou Ané laboratoire de Constitution et Réaction de la Matière UFR Sciences des Structures de la Matière et Technologie Université Félix Houphou&#235t Boigny de Cocody Abidjan C&#244te d’Ivoire département de Mathématiques-Physique-Chimie UFR des Sciences Biologiques Université Peleforo Gon Coulibaly Korhogo C&#244te d’Ivoire Centre National de Floristique Université Félix Houphou&#235t-Boigny de Cocody Abidjan C&#244te d’Ivoire département de Biochimie-Génétique UFR des Sciences Biologiques Université Peleforo Gon Coulibaly Korhogo C&#244te d’Ivoire

A series of 2-(benzylthio)pyrimidines (6a-l) and 2-(benzimidazolylmethylthio)-pyrimidines derivatives (6m and 6n) analogues of ethyl 2-(benzylthio)-6-methyl-4-phenyl-1,4-dihydropyrimidine-5-carboxylates and ethyl 2-(((1H-benzimidazol-2-yl)methyl)thio)-6-methyl-4-phenyl-1,4-dihydropyri-midine-5-carboxylates were prepared and evaluated for antibacterial activity. These compounds were obtained by condensation of 2-thiopyrimidines (4) with benzyl halides or 2-(chloromethyl)-1H

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

Olive Mill Waste Water Management Study by Using Principal Component Analysis

引用

International Journal of Geosciences 2013年第2期4卷 444-453页

作者： Houda Sahnoun mohamed Moncef Serbaji Boubaker Karray Khaled Medhioub département des sciences de la Terre Faculté des Sciences de Sfax Université de Sfax Sfax Tunisie Ecole Nationale d’Ingénieurs de Sfax-laRSEN Université de Sfax Sfax Tunisie Institut Préparatoire Aux etudes d’Ingénieurs de Sfax Université de Sfax Sfax Tunisie Institution de la Recherche et l’Enseignement Supérieur Agricoles Sfax Tunisie

Olive mill waste water (OMWW) is a by-product issued after triturating olives. In Sfax, its management is different from urban to farming area. In this paper we treat it through a statistical analysis study during the season 2005-2006. Principal Component Analysis (PCA) and Hierarchical Classification (HC) methods are carried out on this work. Applied to variables issued from an exhaustive questionnaire including 274 mills, four Principal Components (PCs) are found to be significant, explaining 67% of the total variance. The coordinates of the 13 active variables retained by PCA were used to create a typology relative to the OMWW management and offered 7 groups of individuals which have the same characteristics, explaining 70% of the total inter-variance. This study showed that OMWW management in farming area could causes environmental problems because oleifactors haven’t controlled tanks and could evacuated OMWW on soil (causing oil deposit, waterproofing and possible asphyxia) or on public sewage network (causing corrosion, flow reduction). So, mills transfer from urban to farming areas in the form of agro-industrial complex is needed in the Sfax region.

关键词： Olive Mill Waste Water Management Sfax Principal Component Analysis Hierarchical Classification

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

Small scale biodiesel synthesis from waste frying oil and crude methanol in Morocco

引用

Chinese Journal of Chemical Engineering 2016年第9期24卷 1178-1185页

作者： Fatiha Ouanji Marouane Nachid mohamed Kacimi Leonarda F.Liotta Fabtizio Puleo Mahfoud Ziyad universite Mohammed V Faculte des SciencesDepartement de ChimieLaboratoire de Physico-chimie des Materiaux et Catalyse(URAC26)Avenue lbn BattoutaBP.1014RabatMorocco Hassan 11 Academy of Sdence and Technology RabatMorocco lstituto per lo Studio dei Materiali Nanostrutturati(ISMN)-CNR via Ugo La Malfa15390146 PalermoItaly

Biodiesel was produced at small scale by transesterification of used frying oil（UFO） recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to optimize the transesterification parameters. The cost of the final product was also optimized using low-cost raw *** UFO and the produced biodiesel were characterized with several techniques including gas chromatography,1H NMR,13 C NMR, FTIR, and TGA–TdA techniques.1H NMR gas chromatographic analyses of the final product confirmed that the transesterification in the chosen experimental conditions was completed. These results were confirmed by TGA–TdA analysis used as new techniques to monitoring triglyceride conversion. The biodiesel did not contain any trace of glycerol, and it did meet the international standards. The transesterification at low cost in small scale conditions was performed at 60 ℃ using 1.2% of KOH and a methanol/oil molar ratio of 6：1. A yield of 80.8% was achieved. The properties of the produced biodiesel were found to be as good as those of biodiesels obeying to European standards. The biodiesel production was also performed at small-scale for individual utilisation. Thus, the product was tested in a kerosene stove for heating and non-modified commercial diesel engine producing electricity.

关键词： Biodiesel Transesterification Small-scale Thermogravimetry

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

The Influence of pH on the Swelling Ratio of Acrylic Polymers Networks

引用

材料科学与工程（中英文A版） 2012年第7期2卷 525-529页

作者： Salah Hamri Kamel Boudraa Tewfik Bouchaour Ulrich Maschke laboratoire de Recherche sur les Macromoldcules Facultd des Sciences Universit~ Abou BakrBelkaM BP l l 9 13000 TlemcenAlgdrie ddpartement de Biologie Faculte des Sciences et de la Technologie Universit~ Dr Tahar Moulay Saida Algdrie laboratoire de Chimie Macromoldeulaire (UMR CNRS N8 8009) Batiment C6 Universitd des Sciences et Technologies de Lille59655 Villeneuve d'Ascq Cedex France

The aim of the work is the study of the influence of pH medium on the swelling ratio for poly (n-Butylacrylate) polymer network. Three samples are prepared by sequential UV-curing of the monomers in the presence of a cross-linking agent and a photo-initiator. The solutions with different pH were prepared by the dilution of the acetic acid. Effect of composition is evaluated by measuring the mass of dry and swollen samples. Sample modeling is used to rationalize the experimental results obtained. Good correlation between theoretical and experimental results is mentioned.

关键词：丙烯酸正丁酯聚合物网络溶胀比 pH值 UV-固化光引发剂质量评估交联剂

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

Novel Mannich Bases of Benzimidazole derivatives: An Antibacterial Study of Environmental Bacterial Strains

引用

Advances in Biological Chemistry 2023年第5期13卷 182-191页

作者： Evrard Ablo Ouehi dosso Bakary Coulibaly Kouassi Franscesco Adingra Penayori Marie-Aimée Coulibaly Armand Patrick Achi Tchambaga etienne Camara Souleymane Coulibaly Siomenan Coulibali laboratoire de Constitution et Réaction de la Matière UFR Sciences des Structures de la Matière et Technologie Université Félix Houphou&#235t-Boigny de Cocody Abidjan C&#244te d’Ivoire laboratoire des Procédés Industriels de Synthèse de l’Environnement et des énergies Nouvelles (LAPISEN) Institut National Polytechnique Félix Houphou&#235t-Boigny Yamoussoukro C&#244te d’Ivoire laboratoire d’Agrovalorisation Département de Biochimie-Microbiologie UFR Agroforesterie Université Jean Lorougnon Guédé Daloa C&#244te d’Ivoire

A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.

关键词： Methylbenzimidazole derivatives Inhibit Bacterial Growth Mannich Base Enterobacteria Escherichia coli

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

Flavonoid Glycosides from the Leaves of Glyphaea brevis

引用

Open Journal of Applied sciences 2022年第7期12卷 1296-1303页

作者： Philomène Akoua Yao-Kouassi diane Apie Patricia Gossan Abdulmagid Alabdul Magid Agathe Martinez Charlotte Sayagh laurence Voutquenne-Nazabadioko UFR sciences des Structures de la Matière et de technologie Laboratoire de Constitution et Réaction de la Matière Université Félix Houphou&euml t-Boigny Abidjan République de C&ocirc te d’Ivoire université de San Pedro San Pedro République de C&ouml te d’Ivoire université Péléforo Gon Coulibaly de Korhogo Korhogo République de C&ouml te d’Ivoire CNRS ICMR UMR 7312 Université de Reims Champagne-Ardenne Reims France

A new flavonoid, acacetin-7-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranoside (1), together with four known flavonoids, apigenin-7-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranoside (2), acacetin (3), acacetin-7-O-β-d-glucuronide (4) and genkwanin-5-O-primveroside (5) were isolated from the leaves of Glyphaea brevis. Their structures were elucidated by spectroscopic techniques. The isolated compounds (1 - 5) were tested for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (dPPH) radical scavenging assay. The tested compounds showed slight negative antioxidant activities against dPPH radicals.

关键词： Glyphaea brevis Malvaceae Aca-cetin-7-O-β-d-Glucopyranosyl-(1→2)-β-d-Glucuronopyranoside

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

Impact of Improved Cookstoves on the Level of Household Exposure to CO and PM_2.5 in Sub-Saharan Cities: The Case of the City of Ouagadougou

引用

Open Journal of Air Pollution 2023年第2期12卷 50-66页

作者： Lucmane Koala Kayaba Haro Ousmane Coulibaly Bernard Nana Issoufou Ouarma Edwige Ouedraogo Tizane daho Oumar Sanogo Antoine Béré laboratoire de Physique et de Chimie de l’Environnement (LPCE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Institut de Recherche en sciences Appliquées et technologie (IRSAT) Centre National de la Recherche Scientifique et Technologique (CNRST) Ouagadougou Burkina Faso Institut des sciences (IdS) Ouagadougou Burkina Faso

Air pollution is one of the major global threats to human health. In Burkina Faso, more than 80% of the population uses solid fuels as the main source of cooking energy. This paper reports a comparative study on the exposure of household to the carbon monoxide (CO) and particulate matter (PM2.5) emitted by improved cookstoves (ICS) or traditional cookstoves (TCS). A cross-sectional study was conducted in the city of Ouagadougou for 4 months during the rainy season (July to October) in households with an outdoor kitchen. The investigation involved 92 households where air pollutants, such as PM2.5 and CO were measured with Indoor Air Pollution Meters (IAP meter). These measurements were focused on the concentration levels of the pollutants during cooking. The results of this study show high levels of PM2.5 and CO for all type of stoves. Wood stoves led to higher PM2.5 and lower CO emissions than charcoal stoves. ICS reduce emissions of indoor air pollutants compared to TCS. This reduction raised up to 82% for PM2.5 and 37% for CO. The analysis of the data measured with the student test (t-test) shows that there is a statistically significant difference between the average values of the concentrations of the pollutants emitted with the TCS compared to ICS, except for CO emissions measured on multi-pot sizes cookstoves (MM). This study shows that the concentrations of indoor air pollutants are very high regardless of the type of cookstoves used. The CO exposure obtained varies from 119.10 to 362.72 μg/m3 for 15-minute and 10.83 - 55.11 μg/m3 for 1-hour exposure. The exposure in PM2.5 varies from 4762 to 16,257 μg/m3 for 15-minute and 106.63 to 1597 μg/m3 for 1-hour of exposure. It was noted that the CO exposure levels obtained over 15-minute of exposure are 1.36 to 4.15 times higher than the WHO recommendation and 1.8 times higher for an exposure time of one hou

关键词： Biomass Cookstove Particulate Matters Carbon Monoxide

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

Assessment of Pollution Levels of Suspended Particulate Matter on an Hourly and a daily Time Scale in West African Cities: Case Study of Ouagadougou (Burkina Faso)

引用

Journal of Geoscience and Environment Protection 2020年第11期8卷 119-138页

作者： Issoufou Ouarma Bernard Nana Kayaba Haro Antoine Béré Jean Koulidiati laboratoire de Physique et de Chimie de l’Environnement (LPCE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Institut des sciences (IdS) Ouagadougou Burkina Faso Institut de Recherche en sciences Appliquées et technologie (IRSAT) Centre National de la Recherche Scientifique et Technologique (CNRST) Ouagadougou Burkina Faso

In Western countries, research works on air quality have reinforced in recent years because of the links between the level of particulate pollution in numerous cities and the appearing of various health disorders including cardio-respiratory pathologies, acute bronchopneumonia, lung cancer, etc. In sub-Saharan Africa countries, particularly Burkina Faso, there is very few similar research. In the present work, the pollution levels of airborne particle in the city of Ouagadougou have been assessed through two campaigns of in situ measurements of suspended particulate matter concentrations. These measurements which have concerned PM1, PM2.5 and PM10 were performed using a portable device (AEROCet531S) at nine sites in 2018 and at ten sites in 2019. These sites are located on roadside, administrative services, secondary education establishments and outlying districts. The results show that: 1) the PM1 concentrations values presented no significant variation between days, seasons or sampling sites;2) the 24-hour PM2.5 concentrations often exceeding WHO recommended concentrations and, 3) the 24-hour PM10 concentrations exceed WHO recommended concentrations regardless of the season or the sampling site. In indeed, the average 24-hour concentrations are 20 ± 4, 87 ± 16 and 951 ± 266 μg·m−3 for the PM1, PM2.5 and PM10, respectively. They are 17 ± 3, 29 ± 5 and 158 ± 43 μg·m−3, respectively, in 2018 dry season and, 12 ± 1, 22 ± 9 and 187 ± 67 μg·m−3, respectively, in 2019 rainy season.

关键词： Urban Air Pollution PM1 PM2.5 PM10 AEROCet Ouagadougou

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：