检索结果-南通市图书馆

Phytochemical Screening and Toxicity Assessment of Imperata cylindrica (l.) P. Beauv. (Poaceae) Raw Extracts with Brine Shrimp (Artemia salina) lethality Assay

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 Biosciences and Medicines 2022年第8期10卷 153-171页

作者： Anne Marie léticia Konan Koffi Julien Golly Adou Koffi Mathieu Kra Amissa augustin Adima Essis Esmel Claude lohoues Biochemistry Department Medical Sciences Faculty Felix Houphouet-Boigny University Abidjan C&ocirc te d’Ivoire laboratory of the Biology of Immunity Center Pasteur Institute Abidjan C&ocirc te d’Ivoire Pharmacodynamics Biochemical laboratory Felix Houphouet-Boigny University Abidjan C&ocirc te d’Ivoire Research Department Water Chemicals and Natural Substances INP-HB Yamoussoukro C&ocirc te d’Ivoire

Background: Herbal medicinal preparations are used as dietary supplements for disease prevention and as alternative/complementary medicine. The growing interest in herbal medicine raises the question of its safety and efficacy. Numerous recorded cases of intoxication and toxicological studies reveal that medicinal plants can be toxic, which hinders their safe use. Plant intoxications related to a variety of factors include plant organs and many extraction solvents. little toxicological data on medicinal plants is available. The need to investigate is important for safe use. Imperata cylindrica, a poaceae, is one of the medicinal plants for which few toxicological data are available. Materials & Methods: To expand toxicological data, water, 70% ethanol, and 30% acetone extracts of the leaves and roots, obtained by maceration and reflux methods, were used for phytochemicals molecules qualitative detection and toxicity test by the brine shrimp lethality assay. Results: The qualitative analysis of the different extracts revealed the presence of alkaloids, polyphenolic compounds, saponins, and polyterpenoids. The toxicity endpoint was lethal concentration 50 (lC50). The leaves’ extracts lC50 was between 489.78 μg/ml and 1066.6 μg/ml. As for the root extracts, the lC50 was between 341.98 μg/ml and 1530 μg/ml. Discussion: The different compounds’ presence justifies the use of Imperata cylindrica as a medicinal plant. According to Clarkson classification the root extracts are moderately toxic (lC50: 168.47 μg/ml), and leaf extracts are weakly toxic (lC50: 527.25 μg/ml). The extrapolation made in relation to the Gosselin, Smith, and Hodge scale, allows us to characterize the Imperata cylindrica root and leaf extracts as non-toxic to humans by oral route. Conclusion: This result can be a base for more precise toxicological studies.

关键词： Imperata cylindrica Poaceae Phytochemical Analyses Cytotoxicity Artemia salina

Comparative Study of Energy Absorption Capability of Flat Plate Coupons Made by CFRP Plain Weave Fabric Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Mechanics 2021年第7期11卷 121-145页

作者： Redouane lombarkia augustin Gakwaya Denis Nandlall Marie-laure Dano Julie lé vesque Ameur BenKhelifa Philippe Vachon-Joannette Philippe Gagnon Department of Mechanical Engineering Universit&#233 laval Qu&#233 bec Canada Canada Defence Research & Development Canada Valcartier Qu&#233 bec Canada

Despite years of governmental and academic institutions’ researches, no experimental standards are established for evaluating crush Specific Energy Absorption SEA for plain weave fabric woven carbon-fiber-reinforced composites used in modern aircraft structures as elements of the boxes to mitigate damage during crush events. At the laboratory scale, this paper proposes a comparative study of energy absorption capability of flat plate coupons made by CFRP plain weave fabric composites. A new fixture design and setup were created with hydraulic pressure and drop tower machines to carry out tests of flat plate composite specimens under quasi-static and low velocity on-axis crash loading. For investigating parameters sensibility of triggers and layups, numerical and experimental results of four trigger types and three stacking sequences were compared. A confrontation between experimental and pre-developed Ul-Crush numerical material model results confirms that coupons with 0˚ oriented central plies and saw teeth or corrugated triggers dissipates higher energy during crush, compared to coupons with 90˚ or 45˚ oriented central plies and chamfer 45˚ or steeple triggers. An efficient and simplified experimental methodology was developed to measure and investigate different parameters influencing SEA of composites under crush load. Comparison between experimental and Ul-Crush material model confirms the performance of such simulation tool.

关键词： Crush Behavior Triggers Damage and Failure Mechanisms Crashworthiness SEA

Water/Oil Pickering Emulsion Stabilized by Magnesium Oxide Particles: A Potential System with Two Active Substances (Paracetamol and Griseofulvin)

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 Biophysics 2018年第2期8卷 68-84页

作者： Papa Mady Sy Alphonse Rodrigue Djiboune louis augustin Diaga Diouf Mamadou Soumboundou Boucar Ndong augustin Ndiaye Sidy M. Dieng Ousseynou Diop El Hadji A. l. Bathily Gora Mbaye Mack Faye Mamadou Mbodj Mounibé Diarra laboratory of Physics and Pharmaceutical Biophysics Faculty of Medicine Pharmacy and Odontology UCAD Dakar Senegal laboratory of Medical Biophysics and Nuclear Medicine Faculty of Medicine Pharmacy and Odontology UCAD Dakar Senegal

Pickering emulsions are systems without surfactants, stabilized by solid particles. These emulsions are experiencing a renewed interest, on the one hand, because it is preferable to limit the use of synthetic surfactants for toxicological and environmental reasons and, on the other hand, the need to make new formulations in order to control the drug release patterns by encapsulation or controlled release. Thus, we were interested in the formulation and evaluation of W/O Pickering emulsions stabilized by particles of magnesium oxide with paracetamol in the internal phase and griseofulvin in the external phase. The Bancroft rule served as a model for the formulation. The emulsification was carried out by progressively adding an aqueous phase dispersed in an oil-dispersing phase using a turbo rotor stator mixer. The stability of these emulsions was studied using several parameters (droplet size, pH, viscosity, conductivity ...) and the qualitative and quantitative analysis of the active ingredients by UV-visible spectrophotometry. The results obtained showed that the dye test and the conductivity measurement confirmed the W/O nature of these emulsions. Some parameters such as droplet size, pH and viscosity were strongly influenced by the amounts of magnesium oxide particles and the two active ingredients used. The qualitative and quantitative analysis of the active ingredients confirmed the presence of griseofulvin in the oil phase and paracetamol in the aqueous phase. Thus, we have succeeded in developing a stable W/O Pickering emulsion with magnesium oxide particles. In addition, we were able to incorporate paracetamol into the dispersed phase and griseofulvin into the dispersing phase of the emulsion.

关键词： Emulsion Pickering-Mgo-Griseofulvin-Paracetamol

Diversity and Importance of Benin’s Forests and Agroforestry Systems Woody Species in Mortars and Pestles Manufacture

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 Forestry 2023年第1期13卷 45-60页

作者： Menson Richard Somanin Baba Kayodé Eben-Ezer Ewedje Akossibe Ismaël Batcho Ezin Paul Ogan augustin Orou Matilo Cossi Aristide Adomou Hounnakpon Yedomonhan Université Nationale des Sciences Technologies Ingénierie et Mathématiques (UNSTIM) Abomey Bénin Unité de Recherche Forestière Appliquée Direction Générale des Eaux Forêts et Chasses Ministère du Cadre de Vie et du Développement Durable Cotonou Bénin laboratoire de Botanique et Ecologie Végétale (laBEV) Faculté des Sciences et Techniques (FAST) Université d’Abomey-Calavi (UAC) Cotonou Bénin

The disappearance of resources with high genetic potential and great utility for people and the challenge of the conservation and sustainable management of these resources are two opposing facts of which the world is now concerned. In Benin, forests and agroforestry systems complement each other in wood supply for mortar and pestle manufacture. Thus, this study aimed to investigate the diversity of woody species used for mortar and pestle manufacture and to analyze the preferences of manufacturers through an ethnobotanical approach. Based on the snowball sampling method, and interviews with 112 manufacturers from different ethnic groups, we identified 31 tree species. These species belong to 30 genera and 13 plant families. The Fabaceae are more represented with 14 species (i.e. 45% of the total). Ten are frequently used. But there are four species, such as Vitellaria paradoxa C. F. Gaertn., Prosopis africana (Guill. & Perr.) Taub., Terminalia glaucescens Planch. ex Benth. and Pericopsis laxiflora (Benth.) Meeuwen, which are highly preferred by manufacturers respectively. The calculation of the Indexes of Possession of Global Knowledge (IPSG) revealed that the ethnic group Nagot (0.204) possessed more knowledge and is followed by Mahi (0.201) and Fon (0.18) respectively. Forests and agroforestry systems are both supply sites for manufacturers. The non-parametric Wilcoxon test proved that there are no significant differences between the species’ preference for mortars or pestles manufacture (v = 181, p-value = 0.38). Since the trees cutting in agroforestry systems can be destructive to them, provisions such as the promotion of agroforestry in rural areas and the integration of the used species in the reforestations programs must be taken to curb the pressure and contribute to the conservation of the biodiversity.

关键词： Agroforestry Systems Benin Diversity Forest Mortars and Pestles Uses Woody Species

Diagenetic and Geochemical Study of Sediments from the Cretaceous Basin of Babouri-Figuil (North-Cameroon)

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 Geosciences 2021年第4期12卷 404-417页

作者： augustin Désiré Balla Ondoa Alexis Nyangono Abolo léopold Ekengele Nga Appolinaire Tograne Simon Ngos III Elvine Paternie Edjengte Doumo Armel Zacharie Ekoa Bessa Department of Earth Sciences Faculty of Science University of Ngaoundéré Ngaoundéré Cameroon Department of Mining Oil Gas and Water Resources Faculty of Mining and Petroleum Industries University of Maroua Kaélé Cameroon Department of Earth Sciences Faculty of Science University of Yaoundé I Yaoundé Cameroon

The purpose of this work is to characterize the sediments of the Babouri-Figuil Basin from a diagenetic point of view, the protolith context and weathering conditions, using major element geochemistry and mineralogy of the sedimentary rocks. Microscopic observations of diagenetic phenomena (on and around detrital grains of the basin), and the study of precipitation of the cement show that these sediments have undergone phenomena of compaction, dissolution, recrystallization and cementation. Cementation of quartz by silica is controlled by the rate of precipitation of silica, which is closely related to temperature than pressure. Thus, the sediments of the basin could be influenced by hydrothermalism during diagenesis, which would have inhibited their reservoir quality by generalized cementation phenomena. Geochemical features of the sediments show high contents in SiO2 (47.49 wt% - 90.79 wt%), Al2O3 (2.92 wt% - 23.18 wtle="color:#4F4F4F;font-family:Verdana;">%

关键词： Diagenesis Geochemistry Cretaceous Sediments Babouri-Figuil Basin Sedimentary Basin

Highly Hazardous Pesticides (HHPs) Registered andTheir Use in Sub-Saharan Africa

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 Agricultural Science and Technology(A) 2019年第6期9卷 344-350页

作者： Ngamo Tinkeu léonard Simon Ngatanko Iliassa Tamgno Béranger Raoul Watching Djakissam Madou Chantal Ayiki Evele Nathanael Goudoum augustin Ngassoum Martin-Bénoit Department of Biological Sciences Faculty of ScienceThe University of NgaoundéréP.O.Box 454NgaoundéréCameroon Department of Biological Sciences Faculty of ScienceThe University of MarouaP.O.Box 454814MarouaCameroon Institute of Fisheries and Aquatic Sciences The University of DoualaP.O.Box 7236DoualaCameroon Faculty of Health Sciences The University of BueaP.O.Box 63BueaCameroon National Advanced School of Engineering of Maroua The University of MarouaP.O.Box 46MarouaCameroon Department of Applied Chemistry High School of Food ProcessingThe University of NgaoundéréP.O.Box 455NgaoundéréCameroon

To sustain agricultural production,pesticides are highly *** sub-Saharan Africa,two regulatory bodies are in charge of pesticide registration,for more than 10 years of duty,the impact of their activity has not yet best carried *** present investigation aimed to evaluate the evolution in the quality of pesticides in agriculture in sub-Saharan *** of pesticides began in Cameroon in ***,less than 5%of pesticides used in 2004 were registered and more than 80%of producers were not aware of this legal *** 2014,85%of pesticides used are *** sub-Saharan Africa,Highly Hazardous Pesticides(HHPs)registered are rondenticides,insecticides and *** are frequently used for the protection of stored *** Persistent Organic Pollutants(POPs)(heptachlore,chlorobenzene)and HHP(alluminium phosphide,terbufos,abamectine,ethropophos,etc.)are frequently used to protect stored *** 40%are registered for use in intensive bananas production(28%for nematodes control alone and 10%for control of both insects and nematodes).Moreover,20%of HHPs registered are for the control of rondents.

关键词： Sub-Saharan Africa chemical pest control highly hazardous pesticides alternatives

Improving Radar Rainfall Estimation by Accounting for Microphysical Processes Using a Micro Rain Radar in West Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Climate Sciences 2021年第4期11卷 658-688页

作者： Ghislain Kouadio Eric-Pascal Zahiri Modeste Kacou augustin Kadjo Koffi Abé Delfin Ochou Paul Assamoi laboratoire de Physique de l’Atmosphère et de Mécanique des Fluides (lAPA-MF) UFR SSMT Université Félix Houphou&#235 t-Boigny Abidjan C&#244 te d’Ivoire

This study evaluates the improvement of the radar Quantitative Precipitation Estimation (QPE) by involving microphysical processes in the determination of Z-R algorithms. Within the framework of the AMMA campaign, measurements of an X-band radar (Xport), a vertical pointing Micro Rain Radar (MRR) to investigate microphysical processes and a dense network of rain gauges deployed in Northern Benin (West Africa) in 2006 and 2007 were used as support to establish such estimators and evaluate their performance compared to other estimators in the literature. By carefully considering and correcting MRR attenuation and calibration issues, the Z-R estimator developed with the contribution of microphysical processes and non-linear least-squares adjustment proves to be more efficient for quantitative rainfall estimation and produces the best statistic scores than other optimal Z-Rle="font-family:Verdana;"> algorithms in the literature. We also find that it gives results comparable to some polarimetric algorithms including microphysical information through DSD integrated parameter retrievals.

关键词： Drop Distribution Micro Rain Radar Calibration Microphysical Processes Z-R Relationships Rainfall Estimation

Mineral Fertilizer Use for Optimal Groundnut Production in the Sudano-Guinean and Sudanian Zones of Benin

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 Soil Science 2021年第2期11卷 72-92页

作者： Faki O. Chabi Gustave D. Dagbenonbakin Emile C. Agbangba Issa Mouftaou augustin O. Bankolé Brice T. Oussou léonard E. Ahoton Guillaume l. Amadji Aliou Saïdou Integrated Soil and Crop Management Research Unit Laboratory of Soil Sciences Crop Sciences School Faculty of Agronomic Sciences University of Abomey-Calavi Cotonou Benin Institut National des Recherches Agricoles du Benin Cotonou Benin laboratory of Research in Applied Biology Department of Environmental Engineering Polytechnic School of Abomey-Calavi University of Abomey-Calavi Cotonou Benin laboratoire des Sciences du Sol Eau et Environnement (LSSEE) Centre de Recherche d’Agonkanmey Institut National des Recherches Agricoles du Benin (INRAB) Cotonou Benin laboratory of Soil Science Faculty of Agronomic Sciences University of Abomey-Calavi Abomey-Calavi Benin

Abstract This study aims to determine the optimal N, P, K, Mg and Zn rates for groundnut production on Ferric and Plintic luvisol in the Sudano-Guinean and Sudanian zones of Benin Republic. Two years (2018 and 2019) experiment was carried out in the municipality of Ouessè in the Sudano-Guinean zone and Bembèrèkè in the Sudanian zone. The tested nutrient doses were N (0, 20 and 40 kg⋅ha−1), P (0, 25 and 50 kg⋅ha−1), K (0, 20 and 40 kg⋅ha−1), Mg (0, 15 and 30 kg⋅ha−1) and Zn (0, 4 and 8 kg⋅ha−1). The Box and Behnken rotating design is used to define the N, P, K, Mg and Zn rate combinations leading to 46 combinations. A completely randomized bloc design was setting up considering farmers as replication. In total, four farmers’ fields were selected. A one-way analysis of variance is carried out on yield data, using the linear mixed-effect model. Response surface analyses were used to determine the optimal doses for each N, P, K, Mg and Zn. Nodule production (6.5 times higher than the control), number of gynophores (2.8 times higher than the control) and root length (19.2 ± 0.2 cm) of groundnut plants were significantly (p = 0.0001) improved with nutrient application. The response surface analysis shows that treatments N-P-K-Mg-Zn of 16.01-20.18-6.70-5.65-2.47 (in the Sudano-Guinean zone) and 13.1-25.07-11.47-0-1.82 (in the Sudanian zone) are the optimal rates that have induced optimal yield of 2.1 t⋅ha

关键词： Soil Fertility Response Surface Box and Behnken Design Modeling Micronutrient

A New Ceramide (Rumexamide) and Other Chemical Constituents from <i>Rumex abyssinicus</i>Jacq (Polygonaceae): Isolation, Characterization, Antibacterial Activities and Chemophenetic Significance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Biological Chemistry 2021年第5期11卷 266-282页

作者： léonel Donald Feugap Tsamo lorette Victorine Yimgang Steven Collins N. Wouamba Pierre Mkounga augustin Ephrem Nkengfack laurence Voutquenne-Nazabadioko David Ngnokam Bruno Ndjakou lenta Norbert Sewald Research Unit of Applied and Environmental Chemistry Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Department of Organic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Antimicrobial Agents Unit Laboratory for Phytobiochemistry and Medicinal Plants Studies University of Yaoundé I Yaoundé Cameroon Department of Chemistry Higher Teacher Training College University of Yaounde I Yaoundé Cameroon Groupe Isolement et Structure Institut de Chimie Moléculaire de Reims (ICMR) Reims France Organic and Bioorganic Chemistry Faculty of Chemistry Bielefeld University Bielefeld Germany

The chemical study of Rumex abyssinicus Jacp (Polygonaceae) led to the isolation of a new ceramide named (R)-2'-hydroxy-N-[(2S,3S,4R,16E)-1,3,4-trihydroxyhexacos-16-en-2-yl]hexadecanamide (rumexamide) (1) together with sixteen known compounds: bis-(2-ethylhexyl) phthalate (2), chrysophanol (3), physcion (4), citreorosein (5), emodin (6), chrysophanein (7), physcionin (8), lupeol (9), 3β,28-dihydroxylup-20(29)-ene (10), 3β-dihydroxylup-20(29)-en-28-oic acid (11), oleanolic acid (12), ergosta-6,22-diene-3,5,8-triol (13), stigmastane-3,6-dione (14), a mixture of β-sitosterol (15) and stigmasterol (16), and stigmasterol 3-O-β-D-glucoside (17). Their structures were determined by interpretation of their spectroscopic 1D NMR (1H and 13C NMR), 2D NMR (COSY 1H-1H, HSQC and HMBC) data in conjunction with mass spectrometry (TOFESIMS and HR-TOFESIMS) and by comparison with those reported in the literature. Among all the known compounds, twelve (2, 5, 8-17) were firstly isolated from Rumex abyssinicus, seven (2, 10-14 and 17) from the genus Rumex and three (13, 14, 17) from family Polygonaceae. The in vitro antibacterial activities of extracts (MeOH, n-BuOH and EtOAc),le="font-family:""> as well as compounds 9,

关键词： Polygonaceae Rumex abyssinicus Rumexamide Antibacterial Activities Chemophenetic Significance