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Kinematic Evolution of the Nyakong-Manyi Shear Zone(Adamawa,Cameroon): Constraints from Field Observations and Microstructures,and Implication for Metamorphic P-T-t Estimation

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地球科学学刊:英文版 2023年第5期34卷 1465-1487页

作者： Belmien Robinson Sobze Yemdji Jules Tcheumenak Kouémo Eric Martial Fozing ludovic achu megnemo Julios Efon Awoum Agnes Blandine Kamgang Tchuifong Brice Rostant Tepi Yemele Maurice Kwékam Department of Earth Science University of DschangDschang 67Cameroon Department of Earth Science Faculty of ScienceUniversity of DoualaDouala 24157Cameroon

The Nyakong-Manyi Shear Zone(NMSZ) is a NE-SW elongated corridor found to the northwest of the Foumban-Bankim Shear Zone(FBSZ) along the Central Cameroon Shear Zone. Controversial chronology models has been proposed for the kinematic evolution of the sinistral and dextral shear phases in the Tikar Plain, thus in the FBSZ;early dextral and late sinistral shear phases for some authors and early sinistral and late dextral shear for others. Moreover, the NMSZ kinematic evolution implication on the mylonitization P-T-t path in the area seem to be problematic and the present paper aim is to clear enough those problems;since this shear zone is the main mylonitic corridor that registered the left and right lateral movement in this area. The NMSZ comprises amphibolites, protomylonites, strict sensus mylonites(garnet-kyanite-sillimanite mylonite and garnet-pyroxene mylonite), ultramylonites kyanite-sillimanite and garnet-kyanite-sillimanite gneiss. Field structures testify that the investigated area recorded three deformation phases:(i) the D1deformation phase which is marked by NW-SE to N-S trending S1metamorphic foliation with low to moderate dips(15°–45°) that was transposed during the D2phase, is responsible for a regional metamorphism whose mineral paragenesis is garnet-kyanite-sillimanite;(ii) the early sinistral NNE-SSW to NE-SW shear phase D2marked by S2metamorphic and mylonitic foliations;responsible for, L2stretching mineral lineation, F2fold axes and B2boudins structures;(iii) the late dextral NE-SW shear phase D3, characterized by F3folds, B3boudins and ductile dextral C3shear planes. Mineral paragenesis garnet + kyanite + sillimanite and microstructures within gneiss testify that this rock underwent high grade regional metamorphism whose peak conditions are estimated at 11.5–13.5 kbar/850–900 ℃. After the peak of metamorphism gneiss was overprinted by high grade pressure mylonitization during the early sinistral and late dextral shear deformations. Microstructura

关键词： structural and microstructural features pressure-temperature estimation Nyakong-Manyi Shear Zone Foumban-Bankim Shear Zone Central Cameroon ShearZone tectonics petrology

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Design and Experimental Testing of a Moving Coil Actuator with Compensation Coil

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 707-716页

作者： Boyuan Yin Xianwu Zeng John Frederick Eastham Emelie Nilsson Jean-francois Rouquette Jean Rivenc ludovic Ybanez Xiaoze Pei Department of Electronics&Electrical Engineering University of BathBathBA27AYUnited Kingdom Airbus UpNext BlangnacFrance Airbus CRT BlangnacFrance Department of Mechanical Engineering University of BathBathBA27AYUnited Kingdom

Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization *** DC electric networks are facing great challenges in DC fault protection *** interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low *** this paper a moving coil actuator with compensation coils for a vacuum interrupter,as part of a hybrid direct current circuit breaker,is designed and experimentally *** coils are used to improve operating speed compared with original moving coil *** between four possible connections of compensation coils and original moving coil actuator are carried *** results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor *** performance of each actuator connection is also *** actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed,which is a critical requirement for electric aircraft network *** parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.

关键词： Circuit breaker compensation coil moving coil actuator vacuum interrupter

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Cosmetic or Dietary Vegetable Oils Sampled in the Cameroonian Market May Not Expose Consumers to Lipid Oxidation Products Generating Oxidative Stress and Inflammation

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American Journal of Plant Sciences 2024年第3期15卷 193-202页

作者： Ferdinand Kouoh Elombo Erika Van Damme Clara Delepine David Depraetere ludovic Chaveriat Paul Lunga Keilah Nico Fréderic Njayou Patrick Martin Laboratory of Toxicology and Pharmacology Department of Biochemistry Faculty of Sciences University of Yaound&#233 I Yaound&#233 Cameroon Dé partement de Chimie IUT B&#233thune Universit&#233 d&#8217Artois B&#233thune France Unité Transformations & Agroressources (ULR7519) Universit&#232 d&#8217Artois-UniLaSalle Bethune France

Vegetable oils are a source of energy, essential fatty acids, antioxidants and fat-soluble vitamins useful for human health care and development. These oils also contribute to organoleptic quality of their products’ derivatives. However, their chemical and physical properties can be modified by the mode of their extraction, storage and distribution. These modifications might negatively affect the nutritional quality of the oils. The goals of this study were to: sample different vegetable oils for cosmetic or dietary use marketed in Cameroon, and verify purity and oxidation states of each kind of oil through determination of its acidity, iodine, peroxide, saponification, refractive indexes and the conformity of the labeling. The carotene content, the level of polar components and specific absorbance were also determined. As the result, six oils namely palm, palm kernel, coconut, black cumin, peanut and shea butter were collected. Apart from labeling, chemicals and physicals parameters analyzed were generally in accordance with the Cameroonian and Codex Alimentarius standard. This study suggests that vegetable oils sampled in the Cameroonian market may not expose consumers to lipid oxidation products generating pathological oxidative stress and inflammation. However, efforts in application of existing standard need to be done as far as labeling are concerned.

关键词： Vegetable Oils Quality Control Labeling Compliance Lipid Oxidation Oxidative Pathology

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New 4-imino-4H-Chromeno[2,3-d]Pyrimidin-3(5H)-Amine: Synthesis, Cytotoxic Effects on Tumoral Cell Lines and in Silico ADMET Properties

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International Journal of Organic Chemistry 2024年第3期14卷 107-122页

作者： Marwa Dhiabi Sirine Karoui Mehdi Fakhfakh Souhir Abid Emmanuelle Limanton Rémy Le Guével Thierry Charlier ludovic Paquin Jean-Pierre Bazureau Houcine Ammar Laboratoire de Chimie Applique: Htrocycles Corps et Polymres Facult des Sciences de Sfax Universit de Sfax Sfax Tunisie Institut des Sciences Chimiques de Rennes Universit de Rennes Campus de Beaulieu Rennes Cedex France Department of Chemistry (Science and Arts): Al Qurayat Al-Jouf University Al Jawf Saudi Arabia S2Wave Platform ScanMAT UAR CNRS Universit de Rennes Campus de Beaulieu Rennes Cedex France ImPACcell Platform Biosit SFR UMS CNRS Inserm Campus de Villejean Rennes France Institut de Recherche en Sant Environnement et Travail IRSET Inserm UMR_S Rennes France

The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound.

关键词： 2-Amino-4H-Chromene 4H-Chromeno[2 3-d]Pyrimidin-3(5H)-Amine Microwave Irradiation Tumoral Cell Line in Silico ADMET

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Analysis of Factors Associated with the Abandonment of Nutritional Recovery among Parents of Severely Malnourished Children Aged 6 to 59 Months in the Health District of Titao, Burkina Faso

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Open Journal of Nursing 2024年第9期14卷 477-490页

作者： Aminata Gansore Patrice Ngangue Birama Apho Ly ludovic K. N’Tcha Douglas Mbang Massom Gbètogo Maxime Kiki Josiane Seu Nestor Bationo Noufou Gustave Nana Fla Koueta Institute for Interdisciplinary Training and Research in Health and Education Sciences Ouagadougou Burkina Faso Faculty of Nursing Laval University Quebec Canada Faculty of Medicine and Odonto Stomatology University of Sciences Techniques and Technology of Bamako Bamako Mali Centre de Recherche Entomologique de Cotonou Cotonou Benin Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Centre for Interdisciplinary Research in Rehabilittaion and Social Integration (CIRRIS) Laval University Quebec Canada Faculty of Health Sciences Joseph Ki-Zerbo University Ouagadougou Burkina Faso

Introduction: In Burkina Faso, undernutrition is a public health problem associated with more than 40% of infant and child mortality. Undernutrition management is complex, and there is often a risk of treatment abandonment. Studies on this topic have not explored the influence of environmental and therapeutic factors on parental compliance. This study proposes an analysis of factors influencing the abandonment of nutritional recovery by parents of malnourished children aged 6 to 59 months in ambulatory care. Methods: This was a descriptive and exploratory qualitative study. Data collection took place in February 2020. Data were collected from seventeen (17) participants via in-depth interviews (IDI) and direct observation. The IDIs were transcribed verbatim and thematically analyzed using Nvivo software. Results: The results revealed that factors related to the physical environment, such as geographical inaccessibility, pastoral occupation, displacement at auriferous sites, and insecurity, are important causes of nutritional recovery abandonment. They also prove that factors related to the social environment, such as lack of family and social support, feelings of shame, stigmatization, occupation of the mother, and social events, lead to this abandonment. In addition, therapeutic factors such as interruptions of supplies of Ready to Use Therapeutic Food (RUTF), feeling of improvement or worsening of the state of health, recourse to traditional medicine, and ignorance of undernutrition are also associated with this issue. Conclusion: This study highlighted barriers to the abandonment of nutritional recovery among parents of severely malnourished children aged 6 to 59 months in the health district of Titao, Burkina Faso. It is more important to consider these different factors when evaluating care protocols so that policies to reduce child undernutrition can considerably impact the targets.

关键词： Nutritional Recovery Severe Acute Malnutrition Environmental Factors Therapeutic Factors Abandonment Burkina Faso

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Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

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Advances in Infectious Diseases 2024年第2期14卷 469-477页

作者： Samira Zoa Assoumou Ulrich Leger Davy Mouangala ludovic Mewono Davy-Christ Angoune Ndong Guy Paterne Malonga Mbembo Nely Meungang Alain Moutsinga Elvyre Anita Mbongo Kama Rodrigue Mintsa Nguema Dpartement de Bactriologie-Virologie Universit des Sciences de la Sant Libreville Gabon Laboratoire Professeur Daniel Gahouma Libreville Gabon Departement des Sciences de la vie et de la Terre Ecole Normale Suprieure Libreville Gabon Centre de sant de Glass Libreville Gabon Laboratoire National de Sant Publique Libreville Gabon Dpartement de Biologie et Ecologie Animale Centre National de la Recherche Scientifique et Technologique Libreville Gabon Laboratoire dEcologie des Maladies Transmissibles (LEMAT) Universit Libreville Nord (ULN) Libreville Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

关键词： SARS-CoV-2 Rapid Diagnostic Test Evaluation COVID-19 Antigen Performance

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Assessing the Efficacy of Lemongrass (Cymbopogon citratus) and Sambong (Blumea balsamifera) Extracts in Combating Black Pod Disease: Sustainable Solutions for Controlling Phytophthora megakarya in Cameroon’s Cocoa Plantations

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American Journal of Plant Sciences 2024年第7期15卷 519-537页

作者： Gertrude Membang James Michel Tchotet Tchoumi Godswill Ntsomboh Ntsefong Emmanuel Yvan Mba Ela Sylvere Landry Lontsi Dida ludovic Tchuenkam Tsango Pascal Loïc Ekango Mbondjo Fritz Oben Tabi Innovative Plant Health Laboratory Faculty of Agronomy and Agricultural Sciences (FASA)-Bafia Annex University of Dschang Dschang Cameroon IDepartment of Plant Biology Faculty of Science University of Yaounde 1 Yaounde Cameroon Laboratory of Phytopathology and Crop Protection Faculty of Sciences University of Yaounde 1 Yaounde Cameroon Department of Soil Science Faculty of Agronomy and Agricultural Sciences (FASA) University of Dschang Dschang Cameroon

The use of plant extracts as antifungal agents is gaining increasing attention, particularly for the control of black pod disease in cocoa. Despite extensive research, current strategies haven’t been entirely effective. This study evaluated the effectiveness of Cymbopogon citratus and Blumea balsamifora leaf extracts, both individually and in combination, against Phytophthora megakarya. We assessed the efficacy of the most promising combination (75% B. balsamifera, 25% C. citratus) after storage at room temperature for up to 9 days. Agar microdilution and in vivo bioassays were conducted to determine antifungal susceptibility and effectiveness. Blumea extract exhibited the highest overall inhibitory activity, with the lowest minimum inhibitory concentration (117 µl mL−1) while C. citratus had a narrower range of MIC (146 to 233 µl mL−1). The combination of C. citratus and B. balsamifera demonstrated a synergistic effect against P. megakarya, achieving growth inhibition on V8 media (92.72 ± 4.20% to 100%) and on artificially infected detached pod cortex (92.24 ± 4.53% to 98.75 ± 1.25%), which was not significantly different from the positive control (Ridomil). Furthermore, this combination maintained its effectiveness for up to 9 days at room temperature. These findings suggest that combining plant extracts can enhance their antifungal properties.

关键词： Plant Extracts Antifungal Agents Synergistic Effect Black Pod Disease Cocoa

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A Parametric Genetic Algorithm Approach to Assess Complementary Options of Large Scale Wind-solar Coupling

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IEEE/CAA Journal of Automatica Sinica 2017年第2期4卷 260-272页

作者： Tim Mareda ludovic Gaudard Franco Romerio Institute for Environmental Sciences University of Geneva Geneva School of Economics and Management(GSEM) University of Geneva

The transitional path towards a highly renewable power system based on wind and solar energy sources is investigated considering their intermittent and spatially distributed characteristics. Using an extensive weather-driven simulation of hourly power mismatches between generation and load, we explore the interplay between geographical resource complementarity and energy storage strategies. Solar and wind resources are considered at variable spatial scales across Europe and related to the Swiss load curve, which serve as a typical demand side reference. The optimal spatial distribution of renewable units is further assessed through a parameterized optimization method based on a genetic algorithm. It allows us to explore systematically the effective potential of combined integration strategies depending on the sizing of the system, with a focus on how overall performance is affected by the definition of network boundaries. Upper bounds on integration schemes are provided considering both renewable penetration and needed reserve power capacity. The quantitative trade-off between grid extension, storage and optimal wind-solar mix is *** paper also brings insights on how optimal geographical distribution of renewable units evolves as a function of renewable penetration and grid extent.

关键词： Energy optimization grid integration genetic algorithm optimal spatial distribution power system modeling

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Plasmonics of regular shape particles,a simple group theory approach

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Nano Research 2020年第6期13卷 1597-1603页

作者： Sarra Mitiche Sylvie Marguet Fabrice Charra ludovic Douillard Université Paris-Saclay CEACNRSSPECF-91191Gif sur YvetteFrance Université Paris-Saclay CEACNRSNIMBEF-91191Gif sur YvetteFrance

A simple hand calculation method based on group theory is proposed to predict the near field maps of finite metallic nanoparticles(MNP)of canonical geometries:prism,cube,hexagon,disk,sphere,*** to low order localized surface plasmon resonance *** this article,we report the principles of the group theory approach and demonstrate,through several examples,the general character of the group theory method which can be applied to describe the plasmonic response of particles of finite or infinite symmetry point *** validation is achieved by collection of high-resolution subwavelength near-field maps by photoemission electron microscopy(PEEM)on a representative set of Au colloidal particles exhibiting either finite(hexagon)or infinite(disk,sphere)symmetry point groups.

关键词： surface plasmon resonance group theory hexagon disk sphere photoemission electron microscopy(PEEM)

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Efficient hedging under ambiguity in continuous time

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Probability, Uncertainty and Quantitative Risk 2020年第1期5卷 135-153页

作者： ludovic Tangpi Princeton University Department of Operations Research and Financial EngineeringPrinceton 08540NJUSA

It is well known that the minimal superhedging price of a contingent claim is too high for practical *** a continuous-time model uncertainty framework,we consider a relaxed hedging criterion based on acceptable shortfall *** existing aggregation and convex dual representation theorems,we derive duality results for the minimal price on the set of upper semicontinuous discounted claims.

关键词： Superhedging model ambiguity Acceptance set Risk measure Optimized certainty equivalent Volatility uncertainty

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