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Synthesis,Urease Inhibition and Molecular Modelling Studies of Novel Derivatives of the Naturally Occurring b-Amyrenone

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Natural Products and Bioprospecting 2019年第1期9卷 49-59页

作者： jean j.k.bankeu Hira Sattar Yannick S.F.Fongang Syeda W.Muhammadi Conrad V.Simoben Fidele Ntie-kang Guy R.T.Feuya Marthe A.T.Tchuenmogne Mehreen Lateef Bruno N.Lenta Muhammad S.Ali Augustin S.Ngouela Department of Chemistry Faculty of ScienceThe University of BamendaP.O.Box 39BambiliCameroon International Center for Chemical and Biological Sciences University of KarachiKarachi 75270Pakistan Department of Chemistry Higher Teacher Training CollegeUniversity of MarouaP.O.Box 55MarouaCameroon Department of Pharmaceutical Chemistry Martin-Luther University of Halle-WittenbergWolfgang-Langenbeck-Str.406120 Halle(Saale)Germany Department of Chemistry Faculty of ScienceUniversity of BueaP.O.Box 63BueaCameroon Department of Chemistry Faculty of ScienceScientific and Technical University of MasukuBox 943FrancevilleGabon Department of Chemistry Faculty of ScienceUniversity of Yaounde´IP.O.Box 812Yaounde´Cameroon Multi-Disciplinary Research Laboratory(MDRL) Bahria University Medical and Dental CollegeBahria UniversityKarachiPakistan Department of Chemistry Higher Teacher Training CollegeUniversity of Yaounde´IP.O.Box 47Yaounde´Cameroon

Urease enzyme(UE)has been reported to be a potent virulence factor for Helicobacter pylori(HP)bacteria indicated to be responsible for various gastrointestinal ***,the spread of HP,currently regarded by the World Health Organization as a class 1 carcinogen,could be better controlled by targeting *** is in this line that we have synthesized three new derivatives(2–4)of the naturally occurring olean-12-en-3-one(1),which was previously isolated from the figs of Ficus vallis-choudae Delile(Moraceae).Among the synthesized compounds,3 and 4 contain an indole *** structures were unambiguously assigned by spectroscopic and spectrometric techniques(1D-NMR,2D-NMR and MS).The starting material and the synthesized compounds were screened for UE inhibition activity,and showed significant activities with IC50 values ranging from 14.5 to 24.6 lM,with compound(1)being the most potent as compared to the positive control thiourea(IC50=21.6 lM).Amongst the synthetic derivatives,compound 4 was the most potent(IC50-=17.9 lM),while the others showed activities close to that of the *** addition,molecular docking study of target compounds 2–4 was performed in an attempt to explore their binding mode for the design of more potent UE inhibitors.

关键词： Helicobacter pylori Urease inhibition Docking Olean-12-en-3-one derivatives

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Carbon storage and net primary productivity in Canadian boreal mixedwood stands

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journal of Forestry Research 2019年第5期30卷 1667-1678页

作者： Nicholas j.Payne D.Allan Cameron jean-Denis Leblanc Ian k.Morrison Canadian Forest Service Great Lakes Forestry Centre

Canadian boreal mixedwood forests are extensive,with large potential for carbon sequestration and storage;thus,knowledge of their carbon stocks at different stand ages is needed to adapt forest management practices to help meet climate-change mitigation *** stocks were quantified at three Ontario boreal mixedwood sites.A harvested stand,a juvenile stand replanted with spruce seedlings and a mature stand had total carbon stocks(±SE)of 133±13 at age 2,130±13 at age 25,and 207±15 Mg C ha^-1 at age 81 *** the clear-cut site,stocks were reduced by about 40%or 90 Mg C ha^-1 at *** held 27,34 and 62%of stocks,while detritus held 34,29 and 13%of stocks at age 2,25 and 81,*** soil carbon stocks averaged 51 Mg C ha^-1,and held 38,37 and 25%of *** net primary productivity(±SE)in the harvested and juvenile stand was 2.1±0.2 and 3.7±0.3 Mg C ha^-1 per annum(p.a.),compared to 2.6±2.5 Mg C ha^-1 *** the mature *** mature canopies studied had typical boreal mixedwood composition and mean carbon densities of 208 Mg C ha^-1,which is above average for managed Canadian boreal forest ecosystems.A comparison of published results from Canadian boreal forest ecosystems showed that carbon stocks in mixedwood stands are typically higher than coniferous stands at all ages,which was also true for stocks in vegetation and ***,aboveground net primary productivity was typically found to be higher in mixedwood than in coniferous boreal forest stands over a range of *** from this study,together with those published from the other boreal forest stands demonstrate the potential for enhanced carbon sequestration through modified forest management practices to take advantage of Canadian boreal mixedwood stand characteristics.

关键词： Aboveground net primary productivity Boreal mixedwood forest Carbon stocks Mixedwood stand management Stand age

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A unified electrical model based on experimental data to describe electrical transport in carbon nanotube-based materials

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Nano Research 2020年第6期13卷 1764-1779页

作者： Yoann Dini jérôme Faure-Vincent jean Dijon Univ.Grenoble-Alpes CEALITENDTNMF-38000GrenobleFrance Univ.Grenoble-Alpes CEACNRSIRIGSyMMESF-38000GrenobleFrance

Understanding the electrical transport in carbon nanotube(CNT)materials is one key to reach very high electrical *** CNT material resistivity(ρ(T))as function of the temperature are fully apprehended by their reduced activation W(T)=dln(ρ)/dln(T)*** to now,no model accurately fits W(T)curves,thus preventing from precisely describing the CNT material electrical *** present a new electrical transport model that perfectly fits all W(T)curves found in the literature and in our own *** material resistivities are modeled byρ(T)=ρ0(T^−α+M(1+βTγT^2)).Our model has few enough parameters(α,M,β,γ)to relate them to the CNT *** 70 k,we experimentally show that CNT material resistivity follows the Luttinger Liquid theory justifying the T^−αterm in our *** 70 k,the polynomial part becomes dominant and depends on the two different CNT fabrication techniques which lead to two very different yarn *** yarns made from floating catalyst chemical vapor deposition CNTs,the polynomial is explained by the percolation of metallic CNT ***,the polynomial of yarns spun from CNT arrays is explained by the electrical transport in CNT bundles which are the basic building blocks of this type of yarns.

关键词： carbon nanotube carbon-based materials electrical conductivity electrical transport model Luttinger Liquid

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Type II Fuzzy Logic Based Cluster Head Selection for Wireless Sensor Network

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Computers, Materials & Continua 2022年第1期70卷 801-816页

作者： j.jean justus M.Thirunavukkarasan k.Dhayalini G.Visalaxi Adel khelifi Mohamed Elhoseny Department of Computer Science&Engineering St.Joseph’s College of EngineeringChennai600119India School of Computing Science and Engineering Galgotias UniversityUttar Pradesh203201India Department of Electrical and Electronics Engineering K.Ramakrishnan College of EngineeringTiruchirappalli621112India Department of Computer Science&Engineering Bharath Institute of Higher Education and ResearchChennai600073India Department of Computer Science and Information Technology Abu Dhabi UniversityAbu Dhabi59911United Arab Emirates College of Computer Information Technology American University in the EmiratesDubaiUnited Arab Emirates Faculty of Computers and Information Mansoura UniversityEgypt

Wireless Sensor Network(WSN)forms an essential part of *** is embedded in the target environment to observe the physical parameters based on the type of *** nodes inWSN are constrained by different features such as memory,bandwidth,energy,and its processing *** WSN,data transmission process consumes the maximum amount of energy than sensing and processing of the ***,diverse clustering and data aggregation techniques are designed to achieve excellent energy efficiency in *** this view,the current research article presents a novel Type II Fuzzy Logic-based Cluster Head selection with Low Complexity Data Aggregation(T2FLCH-LCDA)technique for *** presented model involves a two-stage process such as clustering and data ***,three input parameters such as residual energy,distance to Base Station(BS),and node centrality are used in T2FLCH technique for CH selection and cluster ***,the LCDA technique which follows Dictionary Based Encoding(DBE)process is used to perform the data aggregation at ***,the aggregated data is transmitted to the BS where it achieves energy *** experimental validation of the T2FLCH-LCDAtechnique was executed under three different scenarios based on the position of *** experimental results revealed that the T2FLCH-LCDA technique achieved maximum energy efficiency,lifetime,Compression Ratio(CR),and power saving than the compared methods.

关键词： Clustering data aggregation energy consumption cluster head selection wireless sensor networks

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To forage or hide？ Threat-sensitive foraging behaviour in wild, non-reproductive passerine birds

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Current Zoology 2014年第6期60卷 719-728页

作者： Shaun TURNEY jean-Guy j. GODIN Department of Biology Carleton University Ottawa ON K1 S 5B6 Canada Department of Biology McGill University Montreal QC H3A 1B 1 Canada

Because antipredator behaviours are costly, the threat-sensitive predator avoidance hypothesis predicts that individual animals should express predator-avoidance behaviour proportionally to the perceived threat posed by the predator. Here, we experimentally tested this hypothesis by providing wild passerine birds supplemental food （on a raised feeding platform） at either 1 or 4 m from the edge of forest cover （potential refuge）, in either the presence or absence of a nearby simulated predation threat （a sharp-shinned hawk Accipiter striatus model）. Compared with the control treatment, we observed proportionally fewer bird visits to the food patch, and the birds took longer to re-emerge from forest refuge and return to feed at the food patch, after the hawk presentation than before it. The observed threat-sensitive latency-to-return response was stronger when the food patch was further away from the nearest refuge. Overall, our results are consistent with the predictions of the threat-sensitive predator avoidance hypothesis in that wild passerine birds （primarily black-capped chickadees Poecile atricapillus） exhibited more intense antipre- dator behavioural responses with increasing level of apparent threat. The birds were thus sensitive to their local perceived threat of predation and traded-off safety from predation （by refuging） and foraging gains in open habitat in a graded, threat-sensitive manner [Current Zoology 60 （6）： 719-728, 2014].

关键词： Foraging Predation risk Threat sensitivity Risk taking Distance-to-refuge Birds

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Hybridization of Metaheuristics Based Energy Efficient Scheduling Algorithm for Multi-Core Systems

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Computer Systems Science & Engineering 2023年第1期44卷 205-219页

作者： j.jean justus U.Sakthi k.Priyadarshini B.Thiyaneswaran Masoud Alajmi Marwa Obayya Manar Ahmed Hamza Department of Computer Science&Engineering St.Joseph’s College of EngineeringChennai600119India Department of Computer Science and Engineering Saveetha School of EngineeringSIMATSChennai602105India Department of Electronics and Communication Engineering K.Ramakrishnan College of EngineeringTiruchirappalli621112India Department of Electronics and Communication Engineering Sona College of TechnologySalem636005India Department of Computer Engineering College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia Department of Biomedical Engineering College of EngineeringPrincess Nourah bint Abdulrahman UniversityRiyadh11671Saudi Arabia Department of Computer and Self Development Preparatory Year DeanshipPrince Sattam bin Abdulaziz UniversityAlKharjSaudi Arabia

The developments of multi-core systems(MCS)have considerably improved the existing technologies in thefield of computer *** MCS comprises several processors that are heterogeneous for resource capacities,working environments,topologies,and so *** existing multi-core technology unlocks additional research opportunities for energy minimization by the use of effective task *** the same time,the task scheduling process is yet to be explored in the multi-core *** paper presents a new hybrid genetic algorithm(GA)with a krill herd(kH)based energy-efficient scheduling techni-que for multi-core systems(GAkH-SMCS).The goal of the GAkH-SMCS tech-nique is to derive scheduling tasks in such a way to achieve faster completion time and minimum energy *** GAkH-SMCS model involves a multi-objectivefitness function using four parameters such as makespan,processor utilization,speedup,and energy consumption to schedule tasks *** performance of the GAkH-SMCS model has been validated against two datasets namely random dataset and benchmark *** experimental outcome ensured the effectiveness of the GAkH-SMCS model interms of makespan,pro-cessor utilization,speedup,and energy *** overall simulation results depicted that the presented GAkH-SMCS model achieves energy effi-ciency by optimal task scheduling process in MCS.

关键词： Task scheduling energy efficiency multi-core systems fitness function makespan

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A porous puckered V_(2)O_(5) polymorph as new high performance cathode material for aqueous rechargeable zinc batteries

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journal of Energy Chemistry 2021年第10期30卷 459-468,I0012页

作者： Dauren Batyrbekuly Barbara Laïk jean-Pierre Pereira-Ramos Zhumabay Bakenov Rita Baddour-Hadjean Institut de Chimie et des Matériaux Paris Est(ICMPE) UMR 7182 CNRS et UniversitéParis Est Créteil2 rue Henri Dunant94320 ThiaisFrance School of Engineering National Laboratory AstanaNazarbayev University53 Kabanbay Batyr AvenueAstana 010000Kazakhstan

Aqueous rechargeable zinc batteries are getting increasing attention for large-scale energy storage owing to their advantages in terms of cost,environmental friendliness and ***,the layered puckeredγ’-V_(2)O_(5) polymorph with a porous morphology is firstly introduced as cathode for an aqueous zinc battery system in a binary Zn^(2+)/Li^(+)*** Zn‖γ’-V_(2)O_(5) cell delivers high capacities of 240 and190 mAh g^(-1) at current densities of 29 and 147 mA g^(-1),respectively,and remarkable cycling stability in the 1.6 V-0.7 V voltage window(97%retention after 100 cycles at 0.15 A g^(-1)).The detailed structural evolution during first discharge-charge and subsequent cycling is investigated using X-ray diffraction and Raman *** demonstrate a reaction mechanism based on a selective Li insertion in the1.6 V-1.0 V voltage *** involves a reversible exchange of 0.8 Li^(+)in γ’-V_(2)O_(5) and the same structural response as the one reported in lithiated organic ***,in the extended 1.6 V-0.7 V voltage range,this work puts forward a concomitant and gradual phase transformation from γ’-V_(2)O_(5) to zinc pyrovanadate Zn_(3)V_(2)O_(7)(OH)2.2 H_(2)O(ZVO)during *** mechanism involving the in-situ formation of ZVO,known as an efficient Zn and Li intercalation material,explains the high electrochemical performance here reported for the Zn‖γ’-V_(2)O_(5) *** work highlights the peculiar layered-puckeredγ’-V_(2)O_(5) polymorph outperforms the conventionalα-V_(2)O_(5) with a huge improvement of capacity of 240 mAh g^(-1)vs 80 mAh g^(-1) in the same electrolyte and voltage window.

关键词： Vanadium pentoxide γ-V_(2)O_(5) Cathode Aqueous zinc battery High performance Layered structure Energy storage Renewable energy

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Dynamics of freshwater snails and Schistosoma infection prevalence in schoolchildren during the construction and operation of a multipurpose dam in central Côte d’Ivoire

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Infectious Diseases of Poverty 2017年第1期6卷 810-818页

作者： Nana R.Diakite Mirko S.Winkler jean T.Coulibaly Negnorogo Guindo-Coulibaly jürg Utzinger Eliezer k.N’Goran Laboratoire de Zoologie et Biologie Animale Unitede Formation et de Recherche BiosciencesUniversite Felix Houphouët-Boigny22 BP 522Abidjan 22Cote d’Ivoire Swiss Tropical and Public Health Institute P.O.BoxCH-4002BaselSwitzerland University of Basel P.O.BoxCH-4003BaselSwitzerland Departement Environnement et Sante Centre Suisse de Recherches Scientifiques en Cote d’Ivoire01 BP 1303Abidjan 01Cote d’Ivoire

Background:The construction and operation of small multipurpose dams in Africa have a history of altering the transmission of water-based diseases,including *** current study was designed to investigate the abundance and dynamics of schistosomiasis intermediate host snails and Schistosoma infections in humans during the construction and the first years of operation of a small multipurpose dam in Côte d’***:The study was carried out in Raffierkro and four neighbouring villages in central Côte d’Ivoire between 2007 and *** were collected by two experienced investigators using scoops and forceps for 15 min at each *** were identified at genera and,whenever possible,species level,and subjected to testing for cercarial *** aged 6-15 years were examined once every year for Schistosoma haematobium and *** infection,using urine filtration and duplication kato-katz thick smears,***,551 adults were examined for Schistosoma infection before(june 2007)and 359 individuals 2 years after dam construction(june 2009).Results:Overall,1700 snails belonging to nine different genera were collected from 19 sampling ***(potential intermediate host snails of ***)and Pila were the most common genera,whereas Biomphalaria(potential intermediate host snail of ***),Lymnaea,Physa and Melanoides were found in two *** the first-year sampling period,65 snails were collected,of which 13(20%)were schistosomiasis intermediate *** subsequent years,out of 1635 snails collected,1079(66%)were identified as potential intermediate host for schistosomiasis,but none were shedding *** prevalence of *** among adults in the study area was low(0.4%in 2007 and 0.3%in 2009),whereas the prevalence of *** declined from 13.9%to 2.9%in this two-year ***:The low prevalence of schistosomiasis in humans and the absence of infected intermediate host s

关键词： Schistosomiasis Intermediate host snail Transmission Water resources development and management Multipurpose dam Cote d’Ivoire

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Testicular fine-needle aspiration for the assessmen＇ of intratesticular hormone concentrations

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Asian journal of Andrology 2016年第1期18卷 21-24页

作者： Ada P Lee Mara Y Roth jean-jacques Nya-Ngatchou kat Lin Thomas j Walsh Stephanie T Page Alvin M Matsumoto William j Bremner john k Amory Bradley D Anawalt Department of Medicine University of California San Francisco San Francisco CA USA Department of Medicine and Center for Research in Reproduction and Contraception University of Washington Seattle WA USA Department of Obstetrics and Gynecology University of Washington Seattle WA USA Department of Urology University of Washington Seattle WA USA Department of Medicine Geriatric Research Education and Clinical Center VA Puget Sound Health Care System Seattle WA USA.

Measurement of intratesticular sex steroid concentrations in men informs both the development of male hormonal contraceptives and the understanding of male infertility. Given the challenges of using invasive techniques to measure testicular hormone physiology, our group has used a minimally-invasive fine-needle aspiration technique to measure intratesticular hormones in normal healthy men. Herein, we present a post-hoc analysis of the safety and efficacy of testicular fine-needle aspiration （FNA） completed as part of six clinical trials. From 2001 through 2011, a total of 404 procedures were conducted among 163 research volunteers, 85.9% of which were successful in obtaining sufficient fluid for the measurement of intratesticular steroid concentrations. Pain was the most common side effect, with 36.8% of procedures associated with moderate procedural pain and 4.7% with severe procedural pain. Postprocedural pain was uncommon and abated within a few days. Mild local bruising occurred with 14.9% of procedures. Two serious adverse events （0.5%） required surgical intervention. The risk of an adverse event was not associated with age, body mass index, testicular size, or the volume of fluid aspirated. Testicular FNA to obtain fluid for measurement of intratesticular steroid concentrations frequently causes mild to moderate procedural pain, but serious adverse events occur rarely. Testicular FNA has been instrumental for defining human intratesticular hormone physiology and is a minimally-invasive, safe, effective method for obtaining fluid for research on testicular physiology and pathology.

关键词： male contraception physiology reproductive and urinary testis

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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. Fokou 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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