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Synthesis, Molecular Structure, Anti-Plasmodial, Antimicrobial and Anti-Oxidant Screening of (E)-1-(Phthalazin-1-yl)-1-[(Pyridin-2-yl)Ethylidene]Hydralazine and 1-[2-(1-(pyridine-3- yl)ethylidene)hydrazinyl]phthalazine

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International Journal of Organic Chemistry 2021年第3期11卷 91-105页

作者： Angelbert F. Awantu Godfred A. Ayimele jean jules k. bankeu Edouard A. Nantia Patrick.V. T. Fok.u Fabrice F. Boyom Emmanuel N. Nfor Bruno N. Lenta Silvère A. Ngouela Department of Chemistry The University of Bamenda Bambili Cameroon Department of Chemistry University of Buea Buea Cameroon Department of Biochemistry The University of Bamenda Bambili Cameroon Department of Biochemistry University of Yaoundé I Yaoundé Cameroon Department of Chemistry Higher Teachers’ Training College University of Yaoundé I Yaoundé Cameroon Department of Organic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon

Two new hydralazine hydrochloride-derived Schiff bases: (E)-1-(Phthalazin- 1-yl)-1-[(Pyridin-2-yl)Ethylidene]Hydralazine (PPEH), and 1-[2-(1-(pyridine- 3-yl)ethylidene)hydrazinyl]phthalazine (PEHP), were synthesized and partially characterized by spectroscopic and crystallographic methods including IR and X-ray. The single-crystal X-ray diffraction (SCXRD) analysis of PEHP indicates that the hydralazine moiety of both ligands possesses the exocyclic C=N bond. Both, PPEH and PEHP were tested as antimicrobials and antiparasites. Just PEHP could be considered as slightly antiplasmodial and antibacterial agent. In effect, PPEH showed low antimicrobial activity against one bacterial strain with Minimum Inhibitory Concentration (MIC) value of 250 μg/ml while PEHP showed very interesting activity against 18 out of 19 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PPEH and PEHP showed higher reducing activity on ferric ions compared to Vitamin C. On the other hand, both hidrazaline synthetized derivatives showed as better reducing agents than Vitamin C on ferric io

关键词： Schiff Base Hydralazine Hydrochloride Anti-Plasmodial Activity Antimicrobial Activity Anti-Oxidant Activity

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Dynamics analysis and cryptographic implementation of a fractional-order memristive cellular neural network.model

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Chinese Physics B 2024年第4期33卷 418-433页

作者：周新卫蒋东华 jean De Dieu Nk.pk.p Musheer Ahmad jules Tagne Fossi Nestor Tsafack.吴建华 Department of Information Engineering Gongqing CollegeNanchang UniversityJiujiang 332020China School of Computer Science and Engineering Sun Yat-Sen UniversityGuangzhou 511400China Department of Electrical Engineering and Industrial Computing University Institute of TechnologyDoualaCameroon Department of Computer Engineering Jamia Millia IslamiaNew Delhi 110025India Department of Physics Faculty of ScienceUniversity of YaoundeCameroon Electrical Engineering Department and Industrial Computing of ISTAMA University of DoualaDoualaCameroon

Due to the fact that a memristor with memory properties is an ideal electronic component for implementation of the artificial neural synaptic function,a brand-new tristable locally active memristor model is first proposed in this ***,a novel four-dimensional fractional-order memristive cellular neural network.FO-MCNN)model with hidden attractors is constructed to enhance the engineering feasibility of the original CNN model and its ***,its hardware circuit implementation and complicated dynamic properties are investigated on multi-simulation ***,it is used toward secure communication application *** it as the pseudo-random number generator(PRNG),a new privacy image security scheme is designed based on the adaptive sampling rate compressive sensing(ASR-CS)***,the simulation analysis and comparative experiments manifest that the proposed data encryption scheme possesses strong immunity against various security attack.models and satisfactory compression performance.

关键词： cellular neural network memristor hardware circuit compressive sensing privacy data protection

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Interpretation of Geological and Gravity Data from the Bamilék. Plateau (West-Cameroon): Implication for the Understanding of Its Underground Lithotectonic Geometry

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Journal of Geoscience and Environment Protection 2024年第9期12卷 283-314页

作者： Louis Christian k.mgang Chendjou jean Victor k.nfack.jules Tcheumenak.k.uémo Fidèle k.umetio Armand k.gou Dongmo Department of Earth Sciences Faculty of Science University of Dschang Dschang Cameroon Department of Earth Sciences Faculty of Sciences University of Douala Douala Cameroon Department of Physics Faculty of Sciences University of Dschang Dschang Cameroon

The Bamilék. Plateau represents a k.y domain in the understanding of the geodynamics associated with the central Cameroon shear. The study aimed to highlight the subsurface architecture of the plateaus basement setting with focus on high potential areas for hydrogeological and mining development projects. To this end, geological field observations were carried out. Since the structures sought were near-surface, a separation approach based on the upward continuation method was applied to the Bouguer anomaly grid. A set of processing techniques, including vertical derivative or DZ, analytical signal or SA and categorization of gravity signatures, was applied to generate the residual map. The synthesis geological model, obtained from analysis and interpretation of the various transformed maps and 2.5D modeling of two gravity profiles P1 and P2 highlights the following features: 1) intrusions of steep-sided granitic batholiths from Dschang to Bandjoun (profile P1), increasing in width from NW (Dschang) to SE (Bandjoun);2) larger volume batholiths with moderate sides located at Bafang and Bangangté (profile P1). These plutonic massifs were weak.ned by brittle deformation, which favored the emplacement of phonolite or anorthosite dyk.s within them. The emplacement of these dyk.s was accompanied by compressional faults with high dip between Dschang and Bandjoun and extensional faults with medium dip between Bafang and Bangangté. These fault zones (trending N85E to N95E) are ideal for hydrogeological investigations in a basement setting, as well as a series of dyk. network. that could potentially be preferred zones for the circulation and accumulation of useful substances. The resulting geological sections P1 and P2 highlight the influence of granitic intrusions in the geological system of the study area, as well as the structural control associated with the various dyk. intrusions. All the models obtained can serve as fundamental references for hydrogeological and mining e

关键词： Bamilék. Plateau Gravity Measurement Gravity Anomalies Lineaments

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Optimized Adsorption of Small and Medium Molecules by a Biosorbent Based on Hevea Hulls

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Journal of Materials Science and Chemical Engineering 2024年第9期12卷 69-83页

作者： Djedjess Essoh jules César Meledje Yapo Hermann Aristide Yapi David Léonce k.uadio Djamatchè Paul Valéry Ak.sse k.lo Yeo Laboratoire des Sciences Physiques Fondamentales et appliques Ecole Normale Suprieure dAbidjan Abidjan Cte dIvoire Mathmatiques physiques Chimie Physique UFR Environnement Universit Jean Lorougnon Gud Daloa Cte dIvoire

In the context of the recovery of agricultural waste, many researches have focused on the preparation of adsorbents from natural waste from fruit trees, egg shells, palm waste or sawdust. This work.aims to optimize the preparation of a biosorbent from rubber hulls by studying its ability to adsorb small and medium molecules. The influence of parameters such as drying temperature (X1), particle size (X2), stirring time (X3) and sodium hypochloride mass (X4) was studied. The results indicate that the model used for biosorbent optimization on methylene blue and iodine index is significant. In addition, this model has greater adsorption capabilities on small molecules than with large molecules. Statistical analysis of the data shows that temperature is the most influential factor in the adsorption of small molecules. On the other hand, particle size has a significant influence on the adsorption of large molecules. The optimum biosorbent preparation values are 1.0 for drying temperature (X1), −1.0 for biosorbent grain size (X2), 1.0 for stirring time (X3) and 1.0 for sodium hypochloride mass (X4).

关键词： Optimization Biosorbent Methylene Blue Index Iodine Index Rubber Hulls

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Efficiency and productivity analysis of vegetable farming within root and tuber-based systems in the humid tropics of Cameroon

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Journal of Integrative Agriculture 2017年第8期16卷 1865-1873页

作者： Ajapnwa Ak.min jean-Claude Bidogeza jules Rene Mink.ua N Victor Afari-Sefa Faculty of Economics and Management University of Yaounde IIP.O.Box 18 Soa YaoundeCameroon Liaison Office Cameroon West and Central AfricaWorld Vegetable CenterP.O.Box 2008 Messa YaoundeCameroon Samank. Research Station West and Central AfricaWorld Vegetable CenterP.O.Box 320 BemakoMali

The study analyzes the technical efficiency of vegetable farmers in root and tuber-based farming systems within selected sites of the humid tropics of Cameroon. Multistage sampling was used to collect primary data from a cross-section of vegetable farmers drawn from eight selected sites in Santa sub division, Northwest region of Cameroon. Stochastic frontier analysis was used to estimate the technical efficiency of vegetable farmer and to examine its determinants. The results showed that farmyard manure was the most productive factor input, followed by farm equipment and labor. The mean technical efficiency level was 67%, revealing production shortfalls and indicating possibilities of significantly increasing production with the current input Jevels. Female, as well as more educated farmers were found to be significantly more efficient than their counterparts. The results also showed that farmers become less technical efficient as farm sizes become larger. Our study findings suggest that smallholder farmers＇ access to manure, farm implements, and increased women participation in vegetable farming, will produce huge payoffs in vegetable production efficiency in Cameroon.

关键词： technical efficiency vegetable productivity farming systems intensification crop diversification stochasticfrontier analysis

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Land use impact on clay dispersion/flocculation in irrigated and flooded vertisols from Northern Cameroon

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International Soil and Water Conservation Research 2018年第3期6卷 237-244页

作者： Simon Djak.a Basga DésiréTsozue jean Pierre Temga jules Balna jean Pierre Nguetnk.m Institute of Agricultural Research for Development(IRAD) P.O.Box33MarouaCameroon Department of Earth Sciences Faculty of ScienceUniversity of MarouaP.O Box814MarouaCameroon Department of Earth Sciences Faculty of ScienceUniversity of Yaoundé1P.O Box812YaoundéCameroon Department of Earth Sciences Faculty of ScienceUniversity of NgaoundéréP.O Box454NgaoundéréCameroon

Clay dispersion by water is important for soil and water conservation as well as for irrigation scheduling. In the present study, clay dispersion/flocculation of irrigated and flooded vertisols in North Cameroon was investigated using clay dispersion/stability indices. Nine vertisols topsoils (0–20 cm) samples were collected on different land use and their clay dispersion indices were assessed. Vertisols were acidic to slightly basic, with smectites as dominant clay mineral. The water dispersible clay (160–340 g k.-1), the dispersion ratio (0.55–0.79) and the clay dispersion ratio (0.48–0.83) were high in the studied vertisols while the clay flocculation index (0.17–0.54) and the clay aggregation (70–230 g k.-1) were low to moderate, indicating their high dispersion. Cropped vertisols displayed the higher amount of water dispersible clay while not cropped recorded the smaller amount. Concerning the cropped soils, irrigated vertisols displayed the highest clay dispersion indices suggesting that agricultural practices (irrigation) enhance clay dispersion. Globally, the clay dispersibility trend was: irrigated paddy ? rainy sorghum ? rainfed paddy ? dry-season sorghum ? not cropped. Statistical analyses revealed that amorphous Al, Na+ and electrical conductivity enhance clay dispersion while organic matter, nitrogen and Ca++ promote clay flocculation/aggregation. The overall findings emphasized that practices such as heavy tillage and irrigation induce clay dispersion. Minimum tillage, electrolytes concentration monitoring in irrigation water, irrigation scheduling based on soil moisture control, organic matter inputs and implementation of adapted dams are measures susceptible to limit their degradation through clay dispersion.

关键词： Vertisols Clay dispersion Irrigation Land use North Cameroon

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Antibacterial and Antibiotic-Potentiation Activities of Some Cameroonian Food Plants against Multi-Drug Resistant Gram-Negative Bacteria

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Chinese Journal of Integrative Medicine 2014年第7期20卷 546-554页

作者： Simplice B.Tank.o Stephen T.Lacmata Jaures A.k.Noumedem jean P.Dzoyem jules R k.iate Victor k.ete k.iate and Victor Kuete Department of BiochemistryFaculty of ScienceUniversity of Dschang Department of Biochemistry Faculty of ScienceUniversity of Dschang

Objective： To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant （MDR） phenotypes. Methods： The antimicrobial activity of the extracts was performed using the broth microdilution method. The phytochemical screening of these extracts was also performed using standard methods. Resalts： Ocimum basilicum, Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria. The extracts from G. africanum and E. robusta were the most active with the lowest minimal inhibitory concentration of 64 p, g/mL on Escherichia coil AG100A for both extracts and also against k.ebsiella pneumoniae k.4 for G. africanum. When tested in the presence of phenylalanine-arginine 13 -Naphtylamide （PA 13 N）, an efflux pump inhibitor, the extract of Thymus vulgafis and E. Robusta showed the best activities on most tested strains. E. Robusta extract showed good synergistic effects, improving the activity of commonly used antibiotics in about 85% of cases. Coaclasion： The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.

关键词： food plants Cameroon multidrug resistant Gram-negative bacteria efflux pumps

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DFT Study of Geometrical and Vibrational Features of Sulfur Containing Amino Acids in Hydrated Media： L-Cysteine and L-Methionine

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Journal of Chemistry and Chemical Engineering 2013年第9期7卷 850-871页

作者： Mama Nsangou Jonathan k.yambo-k.nzapa jean jules Fifen Department of Physical Sciences Higher Teacher's Training College University of Maroua Maroua P.O. Box 46 Cameroon Centre for Atomic Molecular Physics and Quantum Optics Faculty of Science University of Douala Douala P.O. Box 8580Cameroon Department of Physics Faculty of Science University of Ngaoundere Ngaoundere P. O. Box 454 Cameroon

Geometry optimization at the B3LYP/6-31＋＋G＊ level of theory has been undertak.n on clusters containing L-Met （L-methionine） or L-Cys （L-cysteine） surrounded by eight water molecules. The comparison of the structural parameters of L-Met and L-Cys with X-ray experimental values is in good agreement within 4.8%. This result shows that the privileged positions of water molecules and the possible hydrogen bonding network.formed around the back.one of both AAs （amino acids） are adequate. Subsequent calculations of the harmonic vibrational modes followed by a post-processing treatment enable us to assign the vibrational modes of L-Met and L-Cys surrounded explicitly by eight water molecules. The frequencies of the assigned modes are in good agreement with available IR （infra red） and Raman values within 5%.

关键词： DFT (density functional theory) 6-3 1++G(d) sufur containing amino-acids methionine cysteine explicit solvation.

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DFT Study of the Solvent Effects on the Structure, UV-Vis Spectra and the Antioxidant Activity of Caffeic Acid Phenethyl Ester and Some of Its Derivatives

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Journal of Chemistry and Chemical Engineering 2013年第10期7卷 910-923页

作者： Olivier Holtomo Mama Nsangou jean jules Fifen Ousmanou Motapon Laboratory of Fundamental Physics Faculty of Science University of Douala Douala P. O. Box 24157 Cameroun Department of Physics Faculty of Science University of Bamenda Bamenda P. O. Box 39 Cameroon Department of Physical Sciences Higher Teacher's Training College University of Maroua Maroua P. O. Box 46 Cameroon Department of Physics Faculty of Science University of Ngaoundere Ngaoundere P. O. Box 454 Cameroon

In this study, the antioxidative （3-methyl-2-butenyl caffeate）, BC efficiency of CAPE （caffeic acid phenethyl ester） and four of its derivatives （MBC （benzoic caffeate）, P3HC （phenethyl-3-hydroxy-cinnamate） and P4HC （phenethyl-4-hydroxy-cinnamate）） are compared in vacuum and in seven solvents. It turned out that the AA （antioxidant activity） in increasing order was P3HC 〈 P4HC 〈 CAPE 〈 MBC. Effects of solvents on the structure and the antioxidant activity of P3HC, P4HC, BC, MBC and CAPE, were studied at 133LYP/6-31G （d, p） then B3LYP/6-3 I＋G （d, p） level of theory using the conductor polarized continuum model methods. Thermodynamically, the authors showed that solvent effects on bond dissociation enthalpy are very weak.（within 25 k./mol）, but sufficient to influence hydrogen bonds, O-H bond lengths and showed the preferential sites of hydrogen atom cleavage. In addition, solvent notably influences and changes the nature of the scavenging process of ROS （reactive oxygen species）, favouring by this way the HHAT （homolytic hydrogen atom transfer） in non polar solvents, the SPLET （sequential proton loss electron transfer） in polar solvents. Moreover, in chloroform and for the five molecules studied the SET-PT （sequential electron transfer proton transfer） mechanism is preferred compared to the HHAT, because in this solvent the IP is lower than the BDE. TD-DFT calculations revealed that solvent induce a bathochromic effect （red-shift of the wavelengths） coupled to hyperchromic or hypochromic effects.

关键词： CAPE HHAT (homolytic hydrogen atom transfer) SPLET (sequential proton loss electron transfer) SET-PT TD-DFT CPCM B3LYP/6-31+G (d p) B3LYP/6-31+G (d p).

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Vegetation Resources and Goat Foraging Behaviour in Rangeland System in Southern of Madagascar

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Journal of Life Sciences 2014年第11期8卷 902-907页

作者： Arsene jules Randrianariveloseheno jean de Neupomuscene Rak.tozandriny Roger Daccord Laboratory of Animal Nutrition Department of Animal Science Agronomical Science High School University of AntananarivoP.O. Box 175 Antananarivo 101 Madagascar Swiss Federal Research Station for Animal Production and Dairy Products Agroscope Liebefeld Posieux Posieux CH 1725Switzerland

Goat satisfying energy requirements of goat are determined by anatomical body and browse leaves. In High Bassin zone of Mandrare in Southern Madagascar, sampling area of 400 m^2 has been monitored to analysis floristic diversity and Shannon-Weaver index and to establish rangeland typology. With one ram, two castrated goats and three ewes, foraging behaviour, bite rate and forage nutritive value were analyzed in native pastureland during six days at two browsing periods. As results, four pastureland groups were classified with dominant shrubs plants Acacia farnesiana, Poupartia caffra, k.gelianthe madagascariensis and Rhigozum madagascariense. Rangelands sites have presented lower heterogeneity with floristic density （236-658 plants per hectare）, Shannon-Weaver index （0.28-0.95）, maximum diversity （1.04 ± 0.07） with P 〈 0.05. Most of 42 identified fodder plants presented significant difference （P 〈 0.05） and higher nutritive value （35-54% Dry Matter or DM）; mineral matter （70-162 g·k. DM^-1）; Crude Protein （124-175 g·k. DM^-1）; Crude Fibre （203-376 g·k. DM^-1）; Neutral Detergent Fiber （388-548 g·k. DM^-1） and gross energy （3617-4464 k.al·k. DM^-1）. Acaciafarnesiana rangeland was overgrazed with 4.00 to 9.00 bites·mn^-1. In fact, relationships between phytosociology, nutritional parameters and foraging behaviour have been analyzed to improve with autochthonous plants and to manage rangeland in semi arid environment.

关键词： Bite goats foraging behaviour Madagascar.

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