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Open Journal of medical microbiology 2024年第1期14卷 39-49页

作者： Cécile Ingrid Djuikoue Farid Wega Grace Yemina Kombeu cedric Seugnou Nana Christiane Possi Kiyang Lussabella Pohoko medzam Erica megane Noubissi makougoum Nellie mbianga Nkuigoua Herman Koyouo Tagne mérimé Joël Tchinda Talokou Yvonne Valérie Yolande mavoungou Ashu michel Agbor microbiology Department of the Faculty of Health Sciences of the Université des montagnes Bangangté Cameroon Faculty of medicine and Pharmaceutical Sciences University of Douala Douala Cameroon microbiology Department of the Faculty of Health Sciences of Institut Universitaire du Golf de Guinée Douala Cameroon Centre Hospitalier Dominicain St martin de Porres Yaoundé Cameroun Faculté des Sciences de la Santé Université Marien Ngouabi Brazzaville République du Congo

Enterococcus faecalis and Enterococcus faecium rank among the leading causes of nosocomial bacteremia and urinary tract infections. They often persist on hospital surfaces due to their ability to withstand adverse environmental conditions (low or high temperatures, high pH, and high salinity). The global Enterococcus faecalis-Enterococcus faecium ratio is currently shifting towards Enterococcus faecium. Enterococci present variable levels of resistance to certain families of antibiotics. This is the case for aminoglycosides, beta-lactams and cephalosporins. In 2017, WHO ranked Enterococci among priority pathogens for research and development of new antibiotics. The objective of our study was to determine the antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolates from urine and pleural fluid in two hospitals in Cameroon. This cross-sectional and analytic study was carried out between June to August 2023 on hospitalized and day patients in which a cytobacteriological test of urine and pleural fluid was done. The samples were inoculated on CLED Agar for urine and on Chocolate + polyvitex and blood agar (prepared from Columbia agar) for pleural fluid samples and incubated at 37℃ for 18 to 24 hours. Identification of isolates was carried out using the API 20 STREP micro gallery (Biomerieux, France) and tested for antimicrobial susceptibility. The data on socio-demographical and potential risk factors were recorded using self-administered questionnaires and data from laboratory analyses of the specimen were collected in a data capture sheet. Potential risk factors associated with the presence of Enterococci, were evaluated using the logistic regression in univariate and multivariate analysis. P value minantly females. Enterococcus spp were isolated in 27.79% of our samples with Enterococcus faecalis mostly encountered. Enterococcus spp showed a high

关键词： Enterococcus faecalis Enterococcus faecium Healthcare-Associated Infections Antimicrobial Resistance Cameroon

A new approach for fuel injection into a solar receiver/ reactor:Numerical and experimental investigation

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 683-696页

作者： m Helal Uddin Nesrin Ozalp Jens Heylen cedric Ophoff mechanical and Industrial Engineering Department University of Minnesota DuluthDuluthMN 55812-3042USA mechanical Engineering Department 3001 LeuvenBelgium

An innovative and efficient design of solar receivers/reactors can enhance the production of clean fuels via concentrated solar energy. This study presents a new jet-type burner nozzle for gaseous feedstock injection into a cavity solar receiver inspired from the combustion technology. The nozzle design was adapted from a combustion burner and successfully implemented into a solar receiver and studied the influence of the nozzle design on the fluid mixing and temperature distribution inside the solar receiver using a 7 kW solar simulator and nitrogen as working fluid. Finally, a thorough computational fluid dynamics (CFD) analysis was performed and validated against the experimental results. The CFD results showed a variation of the gas flow pattern and gas mixing after the burner nozzle adaptation, which resulted an intense effect on the heat transfer inside the solar receiver.

关键词： solar reactor nozzle CFD heat transfer mixing and recirculation Clean fuels solar receivers nozzles Fuel injection computational fluid dynamics Heat transfer charge flow devices combustion technology mixing of gases FLOW PATTERNS

Effect of successive sprays on liquid distribution in fluidized beds

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Particuology 2021年第1期19卷 17-24页

作者： cedric Briens Liliana Pardo Reyes Franco Berruti Jennifer mcmillan Institute for Chemicals and Fuels from Alternative Resources Western University22312 Wonderland Rd.IldertonONN0M 2A0Canada Edmonton Research Centre Syncrude Canada Ltd942117th AveEdmontonABT6N 1H4 Canada

In processes such as Fluid Coking^(™),agglomerate formation should be minimized since it reduces the yield of valuable products,and degrades operability because of the fouling of *** experimental model,consisting of an aqueous solution of gum arabic with a dye,has been successfully developed to simulate the formation of agglomerates in the Fluid Coking^(™)process,where bitumen is sprayed into a fluidized bed of coke particles The particles wetted by a spray could be predicted by assuming that all the particles in the wake of bubbles formed from the tip of the spray jet have been wetted by the injected *** transfer of liquid from particles wetted with the spray to dry bed particles was relatively ineffective,as the number of wet particles increased by only 50%.With successive liquid injections,the proportion of the liquid trapped in agglomerates increases in latter injections:large agglomerates from earlier injections accumulate above the grid and are carried by gas bubbles into the spray jet cavity,where they seed fresh agglomerates.

关键词： Fluidized bed Liquid injection Agglomerate formation Fluid Coker

Effects of liquid feed rate and impeller rotation speed on heat transfer in a mechanically fluidized reactor

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Particuology 2018年第4期16卷 25-32页

作者： Dhiraj Kankariya cedric Briens Dominic Pjontek Stefano Tacchino Department of Chemical and Biochemical Engineering University of Western Ontario London Ontario N6A 5B9 Canada

A mechanically fluidized reactor （mFR） is a novel and compact reactor used for biomass pyrolysis. Endothermic biomass pyrolysis requires heat provided from the wall of the mFR. meanwhile, mixing with a vertical stirrer helps achieve effective heat transfer from the wall to the bed. Here, the heat trans- fer characteristics between the wall of a 1.0-L mFR and its bed of mechanically fluidized sand particles were studied. An induction heating system was used to heat the wall, while a vertical blade stirrer was used for mixing. Heat transfer measurements were carried out using silica sand particles, having three average Sauter mean diameters： 190, 300, and 600 p.m. The overall wall-to-bed heat transfer coeffi- cients were estimated using temperature measurements taken during continuous injection of water onto the fluidized bed. The overall heat transfer coefficient for bed temperatures of 500-700℃ increased as particle size increased or superficial velocity of the vaporized liquid increased. Effect of impeller rotation speed also was investigated. Typically, the overall heat transfer coefficient increased as rotation speed increased. The wall-to-bed heat transfer coefficients obtained in this study are comparable to estimates from traditional bubbling fluidized beds, even at vapor velocities below the minimum fluidization veloccity.

关键词： mechanical fluidization Induction heating Impeller rotation Heat transfer Particle size

modeling and Analysis of UAV-Assisted mobile Network with Imperfect Beam Alignment

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Computers, materials & Continua 2023年第1期74卷 453-467页

作者： mohamed Amine Ouamri Reem Alkanhel cedric Gueguen manal Abdullah Alohali Sherif S.m.Ghoneim University of Rennes 1/ADOPNET team at IRISA laboratory Rennes35000France Facultéde Technologie Laboratoire d’Informatique Médicale(LIMED)Universitéde BejaiaBejaia06000Algérie Department of Information Technology College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Information Systems College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Electrical engineering department College of EngineeringTaif University P.O.Box 11099Taif21944Saudi Arabia

With the rapid development of emerging 5G and beyond(B5G),Unmanned Aerial Vehicles(UAVs)are increasingly important to improve the performance of dense cellular *** a conventional metric,coverage probability has been widely studied in communication systems due to the increasing density of users and complexity of the heterogeneous *** recent years,stochastic geometry has attracted more attention as a mathematical tool for modeling mobile network *** this paper,an analytical approach to the coverage probability analysis of UAV-assisted cellular networks with imperfect beam alignment has been *** assumption was considered that all users are distributed according to Poisson Cluster Process(PCP)around base stations,in particular,Thomas Cluster Process(TCP).Using thismodel,the impact of beam alignment errors on the coverage probabilitywas ***,the ProbabilityDensity Function(PDF)of directional antenna gain between the user and its serving base station was ***,association probability with each tier was achieved.A tractable expression was derived for coverage probability in both Line-of-Sight(LoS)andNon-Line-of-Sight(NLoS)condition *** results demonstrated that at low UAVs altitude,beam alignment errors significantly degrade coverage ***,for a small cluster size,alignment errors do not necessarily affect the coverage performance.

关键词： Unmanned aerial vehicles coverage analysis stochastic geometry millimeter wave imperfect beam alignment

Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen

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Particuology 2018年第5期16卷 152-159页

作者： Ahmad Hamdan Hiba Kabbara cedric Noel Jaafar Ghanbaja Abdelkrim Redjaimia Thierry Belmonte Universite de Lorraine lnstitutJean tamourUMR CNRS 7198Nancy F-54042France CNRS lnstitutJean LamourUMR CNRS 7198Nancy F-54042France

A simple method to synthesise hexagonal lead sheets,which belong to the class of two-dimensional materials,is *** objects are collected on a substrate located under two lead electrodes, between which nanosecond-pulsed spark discharges are ignited in liquid *** hexagonal sheets are single crystals produced by gas phase *** nitrogen completely evaporates,the sheets change to PbO2by oxidation in *** oxidation process induces stress that pleats the uppermost sheets or open cracks at the *** thickness of the individual objects typically varies from 4to *** the number of discharges is more than about 2000,in addition to sheets,two types of PbO2 sticks start to form:bundles composed of nanosticks (length 5p.m and diameter 50nm)and isolated sticks (length 20μm and diameter 500nm).These new nanostructures mainly form because of the way the discharge erodes the lead ***,anisotropic erosion driven by the orientation of the crystallographic planes of the lead crystals produces octahedra and nanosticks,and the nanosticks grow on the electrode surfaces as discharge *** about 2000discharges,the nanosticks are sufficiently long that they can be easily broken,probably by mechanical stress,and they fall onto the underlying substrate.

关键词： Discharge in hquids Plasma-surface interaction Nanopamcles Liquid nitrogen Lead

Agglomerate behavior in a recirculating fluidized bed with sheds： Effect of ring baffles

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Particuology 2018年第3期16卷 143-151页

作者： Francisco J. Sanchez Careaga cedric Briens Franco Berruti Jennifer mcmillan murray Gray Institute for Chemicals and Fuels from Alternative Resources Western University 22312 Wonderland Rd. Hderton ON NO M2AO Canada Edmonton Research Centre Syncrude Canada Ltd 9421 17th Ave Edmonton AB T6N 1H4 Canada The Petroleum Institute PO Box 2533 Abu Dhabi UAE

The radioactive particle tracking technique was used to study the effect of internal ring baffles on wet agglomerate motion inside a cold flow recirculating fluidized bed. The study found that using such a baffle on its own or above the regular sheds helps reduce the fouling of the stripper section by increasing the residence time that the agglomerates spend above the baffle, thereby reducing the release of the vapors below the baffles that cause fouling of the sheds. Adding down-comers, or flux tubes, to the ring baffles degrades the performance of the baffles, Reducing the length of the flux tubes, so that they do not reach the bottom of the baffle lip results in a further degradation in baffle performance.

关键词： Radioactive particle tracking Fluidized bed Fluid coker Baffles

Short-term feeding behaviour sound classification method for sheep using LSTm networks

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International Journal of Agricultural and Biological Engineering 2021年第2期14卷 43-54页

作者： Guanghui Duan Shengfu Zhang mingzhou Lu cedric Okinda mingxia Shen Tomas Norton College of Artificial Intelligence Nanjing Agricultural UniversityNanjing 210031China Computer College Qinghai Nationalities UniversityXining 810007China m3-BIORES-measure Model&Manage BioresponsesKU LeuvenHeverlee/Leuven 3001Belgium

A deep learning approach using long-short term memory(LSTm)networks was implemented in this study to classify the sound of short-term feeding behaviour of sheep,including biting,chewing,bolus regurgitation,and rumination *** original acoustic signal was split into sound episodes using an endpoint detection method,where the thresholds of short-term energy and average zero-crossing rate were utilized.A discrete wavelet transform(DWT),mel-frequency cepstral,and principal-component analysis(PCA)were integrated to extract the dimensionally reduced DWT based mel-frequency cepstral coefficients(denoted by PW_mFCC)for each sound ***,LSTm networks were employed to train classifiers for sound episode category *** performances of the LSTm classifiers with original mel-frequency cepstral coefficients(mFCC),DWT based mFCC(denoted by W_mFCC),and PW_mFCC as the input feature coefficients were *** results demonstrated that the introduction of DWT improved the classifier performance effectively,and PCA reduced the computational overhead without degrading classifier *** overall accuracy and comprehensive F1-score of the PW_mFCC based LSTm classifier were 94.97%and 97.41%,*** classifier established in this study provided a foundation for an automatic identification system for sick sheep with abnormal feeding and rumination behaviour pattern.

关键词： sheep behaviour short-term feeding behaviour acoustic analysis mel-frequency cepstral coefficients long-short term memory networks

Levels of insecticide resistance to deltamethrin,malathion,and temephos,and associated mechanisms in Aedes aegypti mosquitoes from the Guadeloupe and Saint martin islands(French West Indies)

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Infectious Diseases of Poverty 2017年第1期6卷 339-353页

作者： Daniella Goindin Christelle Delannay Andric Gelasse cedric Ramdini Thierry Gaude Frederic Faucon Jean-Philippe David Joël Gustave Anubis Vega-Rua Florence Fouque Laboratory of medical Entomology Unit Environment and HealthPasteur Institute of Guadeloupe97183 Les AbymesGuadeloupe Vector control Service Regional Health AgencyDothemareLes AbymesGuadeloupe Alpine Ecology Laboratory(LECA) CNRSUMR 55532233 rue de la piscine BP5338041 GrenobleCedex 9France University of Grenoble Alpes GrenobleFrance Environmental and Systems Biology(BEeSy) University of Grenoble AlpesGrenobleFrance Vector Environment and Society Unit Special Programme for Research and Training in Tropical Diseases(TDR)World Health Organization20Avenue AppiaCH-1211 Geneva 27Switzerland

Background:In the Guadeloupe and Saint martin islands,Aedes aegypti mosquitoes are the only recognized vectors of dengue,chikungunya,and Zika *** around 40 years,malathion was used as a mosquito adulticide and temephos as a *** the European Union banned the use of these two insecticide molecules in the first decade of the 21st century,deltamethrin and Bacillus thuringiensis *** are the remaining adulticide and larvicide,respectively,used in *** order to improve the management of vector control activities in Guadeloupe and Saint martin,we investigated *** resistance to and mechanisms associated with deltamethrin,malathion,and ***:*** mosquitoes were collected from six different localities of Guadeloupe and Saint *** were used for malathion and temephos bioassays,and adult mosquitoes for deltamethrin bioassays,following World Health Organization *** resistance(Kdr)genotyping for V1016I and F1534C mutations,and expression levels of eight enzymes involved in detoxification mechanisms were examined in comparison with the susceptible reference Bora Bora ***:Resistance ratios(RR50)calculated for *** larvae showed high resistance levels to temephos(from 8.9 to 33.1-fold)and low resistance levels to malathion(from 1.7 to 4.4-fold).Adult females displayed moderate resistance levels to deltamethrin regarding the time necessary to affect 50%of individuals,varying from 8.0 to *** investigations on adult mosquitoes showed high resistant allele frequencies for V1016I and F1534C(from 85 to 96%and from 90 to 98%,respectively),as well as an overexpression of the glutathione S-transferase gene,GSTe2,the carboxylesterase CCEae3a,and the cytochrome genes 014614,CYP6BB2,CYP6m11,and ***:*** populations from Guadeloupe and Saint martin exhibit multiple resistance to organophosphates(temephos and malathion),and pyrethroids(deltamethrin

关键词： Aedes aegypti mosquitoes Insecticide resistance Deltamethrin malathion Temephos Guadeloupe Saint martin