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Low-temperature catalytic methane deep oxidation over sol-gel derived mesoporous hausmannite (Mn_(3)O_(4)) spherical particles

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ChemPhysMater 2024年第3期3卷 329-340页

作者： Patrick Ndouka Ndouka Stephane Kenmoe jacques richard mache Elie Acayanka Dick Hartmann Douma Ralph Gebauer Patrick Mountapmbeme Kouotou Department of Chemistry Faculty of SciencesUniversity of MarouaP.O.Box 814 MarouaCameroon Department of Theoretical Chemistry University of Duisburg-EssenD-45141 EssenGermany Department of Mining Engineering School of Geology and Mining EngineeringUniversity of NgaoundéréP.O.Box 115 MeigangaCameroon Department of Inorganic Chemistry Faculty of ScienceUniversity of YaoundéIP.O.Box 812 YaoundéCameroon Groupe de Simulations Numériques en Magnétisme et Catalyse Facultédes Sciences et TechniquesUniversitéMarien NgouabiB.P.69 BrazzavilleCongo The Abdus Salam International Centre for Theoretical Physics(ICTP) 34151 TriesteItaly National Advanced School of Engineering of Maroua University of MarouaP.O.Box 46 MarouaCameroon Higher Institute of Agriculture WoodWater and EnvironmentUniversity of EbolowaP.O.Box 118 EbolowaCameroon

In this study,Mn_(3)O_(4) spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn_(3)O_(4) exhibited a tetragonal spinel structure,and Fourier transformed infrared(FTIR)spectroscopy identified surfaceadsorbed functional *** electron microscopy(SEM)and the specific surface area analyses by Brunauer−Emmett−Teller(BET)revealed a porous,homogeneous surface composed of strongly agglomerated spherical grains with an estimated average particle size of∼35 nm,which corresponded to a large specific surface area of∼81.5 m^(2)/g.X-ray photoelectron spectroscopy(XPS)analysis indicated that Mn_(3)O_(4) was composed of metallic cations(Mn^(4+),Mn_(3)+,and Mn^(2+))and oxygen species(O_(2)−,OH−and CO_(3)2−).The optical bandgap energy is∼2.55 *** of the catalytic performance of the Mn_(3)O_(4) SPs indicated T90 conversion of CH4 to CO_(2) and H2O at 398℃ for gas hourly space velocity(GHSV)of 72000 mL^(3) g^(−1) h^(−1).This observed performance can be attributed to the cooperative effects of the smallest spherical grain size with a mesoporous structure,which is responsible for the larger specific surface area and available surface-active oxygenated *** cooperative effect of the good reducibility,higher ratio of active species(OLat/OAds),and results of density functional theory(DFT)calculations suggested that the total oxidation of CH4 over the mesoporous Mn_(3)O_(4) SPs might take place via a two-term process in which both the Langmuir−Hinshelwood and Mars−van Krevelen mechanisms are cooperatively involved.

关键词： Sol-gel Manganese oxide Catalytic oxidation Methane Langmuir−Hinshelwood mechanism Mars−van Krevelen route Two−term process

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Clay Materials for Ceramics Application from N’Djamena in the Chad Republic: Mineralogical, Physicochemical and Microstructural Characterization

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Journal of Materials Science and Chemical Engineering 2024年第2期12卷 31-48页

作者： Ndjolba Madjihingam Djoda Pagore jacques richard mache Bebbata Warabi Bertin Pagna Kagonbe Patrick Mountapmbeme Kouotou Department of Civil Engineering National Advanced School of Engineering University of Maroua Maroua Cameroon Department of Mining Engineering School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Local Materials Authority Promotion (MIPROMALO) Yaoundé Cameroon Department of Environmental Sciences Advanced School of Agriculture Forestry Water and Environment University of Ebolowa Ebolowa Cameroon

Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO2 (~57% - 66%), Al2O3 (~13% - 15%), Fe2O3 (~6% - 10%), TiO2 (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K2O, CaO, Na2O). Negligible and trace of MgO (~1%) and P2O5 was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application.

关键词： Clay Soils Characterization Mineralogy Physicochemical Properties Ceramic Application

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Epidemiological, Clinical Progress Aspects of Congenital Heart Disease with Neonatal Revelation at the Mother-Child Hospital of Bingerville (HME) Concerning 98 Cases from January 2021 to December 2022 (Côte d’Ivoire)

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Open Journal of Pediatrics 2024年第1期14卷 89-100页

作者： Adja Evelyne Akaffou-Gbery richard Azagoh-Kouadio Anne-Lise Laetitia Mobio Jean-jacques Yao Atteby Serenah Marie Janice N’vrah Anoh Kouassi Raoul Yao Department of Paediatrics and Neonatology H&#244pital Mère-Enfant de Bingerville (HME) Bingerville C&#244te d’Ivoire Department of Medical Pediatrics and Specialties CHU de Angré Abidjan C&#244te d’Ivoire

Introduction The distribution of congenital heart disease (CHD) in sub-Saharan Africa is highly imprecise and varies from one region to another due to the inequality of diagnostic facilities. The aim of this study was to determine the in-hospital prevalence of congenital heart disease in children at the Mother-Child hospital of Bingerville (HME) by specifying the diagnostic, therapeutic and evolutionary aspects. Materials and methods We conducted a retrospective, descriptive, cross-sectional study at HME of Bingerville from January 2021 to December 2022. All newborns with congenital heart disease confirmed by echocardiography were included in the study. Results Of 656 admissions to the neonatology department over the study period, congenital heart disease accounted for 14.9% (98/656) of cases. In our series, 76.7% were diagnosed before the 1st week of life, with a mean chronological age of 5.18 days and extremes of 0 and 46 days. There were as many male patients (50%) as female (50%), i.e. a sex ratio of 1. These newborns were premature in 60.2% of cases, with a mean and median gestational age of 34 weeks’ amenorrhea. Most were left-right shunts (90.8%). Persistent ductus arteriosus (PDA) (48.9%) predominated, followed by atrial septal defect (38.7%), ventricular septal defect (13.3%), common trunk artery (CTA) (3.1%) and open septal pulmonary atresia (OSPA) (1%) as the primary cyanogenic heart disease. Pulmonary arterial hypertension (PAH) (50%) was primary in 38.8% and secondary (61.2%). The mortality rate was 30.6%, and all CTA patients died (100%), with a significant statistical relationship (p = 0.027). Progression under treatment was marked by clinical stabilization (68/98) in 69.4% of cases. Conclusion: Congenital heart disease is relatively common at the Bingerville HME. Access to echocardiography should be facilitated in neonatology departments for rapid diagnosis and optimal management of congenital heart disease in newborns.

关键词： Newborn Congenital Heart Disease Côte d’Ivoire

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Valorization of Pozzolans as Partial Additive of Portland Cement: A Case of Pozzolans from the Localities of Foumbot, Penja and Tombel (Cameroon)

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Journal of Minerals and Materials Characterization and Engineering 2019年第1期7卷 18-33页

作者： Mambou Ngueyep Luc Leroy Njimboum Aboubakar Sidiki Tchakouteu Mbakop Théophile mache jacques richard Laboratory of Materials Science Department of Physics Faculty of Science University of Yaoundé 1 Yaoundé Cameroon Department of Mining & Extractive Metallurgy School of Geology & Mining Engineering University of Ngaoundéré Ngaoundéré Cameroon Laboratory of Applied Inorganic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Laboratory of Materials Local Materials Promotion Authority MINRESI/MIPROMALO Yaoundé Cameroon

The objective of this study is to find alternative materials that can be used as an addition in cement in order to produce ecological and economical cement. Three pozzolans coming from different volcanic regions of Cameroon (Penja, Tombel and Foumbot) were sampling. Mechanical compressions on 40 × 40 × 160 mm3 mortar specimens were made with partial replacements of 2%, 4%, 6% and 8% of the pozzolans in Portland cement and physical analyzes on the mortar powders were carried out. The values of the activity indices of different pozzolans obtained are in the normative range. The compressive strength of motars decreases at all ages with the proportion of cement substitution. The compressive strength values up to 40 Mpa are obtained for a substitution of 6% for the pozzolans from Penja, Tombel and 8% for the pozzolan from Foumbot. Pozzolan from Foumbot which contains the highest percentage of SiO2 offers a maximum substitution rate and therefore optimally reduces the production costs of Portland cement. Physical tests show that specific surfaces increase with an additions of pozzolans from Tombel and Penja.

关键词： Pozzolan Mortars Compressive Strength Tensile Strength

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From the dilute solution to the pure compound:Extraction strategy based on a multi-stage process of phase separation

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Science China Chemistry 2010年第9期53卷 2070-2076页

作者： GOUTAUDIER Christelle TENU richard COUNIOUX Jean-jacques Université de Lyon Université Claude Bernard Lyon 1Laboratoire Multimatériaux et Interfaces

It is very rare that a one-step process of extraction leads to the pure compound with a high degree of purity specified by an industrial *** various stages of a synthesis process and possible secondary reactions may lead to the synthesis of more or less complex and highly diluted *** this work,the rationale and strategy for extraction and purification of a high added value compound are *** the thinking is based on the knowledge and the exploitation of phase diagrams and then developed for different unit operations of the *** most significant research tools are the experimental data and the modelling of phase equilibrium to estimate the yield of each step of *** significant example chosen involves all the basic methods of phase separation,starting with liquid-vapour equilibrium:stripping of high volatility components and then more or less complex distillation are classically *** theoretical plateau number can be deduced from the equilibrium equation *** second step is based on the study of the liquid-liquid equilibrium and is an intermediate step for enrichment of the solution when distillation is not possible.A final step based on solid-liquid equilibrium consists of the selective crystallization of the pure product at low temperature,in order to satisfy the requirements of purity and safety imposed by industrial *** conclusion includes all isolation operations in the form of a general extraction and purification scheme.

关键词： phase diagram azeotropic distillation liquid-liquid extraction selective crystallization

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Model-independent constraints on spin observables

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Chinese Physics C 2009年第12期33卷 1153-1158页

作者： Jean-Marc richard Xavier Artru Mokhtar Elchikh jacques Soffer Oleg Teryaev LPSC Université Joseph Fourier CNRS/IN2P3 INPG Grenoble France Université de Lyon IPNL Université Lyon 1 and CNRS/IN2P3 Villeurbanne France Université des Sciences et de Technologie d'Oran El Menauoer Oran Algeria Physics Department Temple University Philadelphia PA 19122 -6082 USA Bogoliubov Laboratory of Theoretical Physics JINR 141980 Dubna Russia

We discuss model-independent constraints on spin observables in exclusive and inclusive reactions, with special attention to the case of photoproduction.

关键词： spin observables positivity exclusive reactions inclusive reactions

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Typology of Local Construction Materials from the Adamawa and North-West Regions of Cameroon

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Geomaterials 2016年第2期6卷 50-59页

作者： Zo’o Zame Philémon Nzeukou Nzeugang Aubin Uphie Chinje Melo mache jacques richard Ndifor Divine Azigui Nni Jean Department of Earth Sciences University of Yaoundé Yaoundé Cameroon Local Materials Promotion Authority (MIPROMALO) Yaoundé Cameroon National Civil Engineering Laboratory (LABOGENIE) Yaoundé Cameroon

This article summarizes the different local construction materials observed in two regions of Cameroon (Adamawa and North-West). These raw materials were mapped and evaluated using various methods of investigation (spatial distribution, estimation of reserves, development of a database compatible with geo-referenced maps). The results obtained show three types of local construction materials (vegetal, pedological and geological) with quantitative estimation or distribution. Vegetal local materials include herbaceous savanna with strong dominance of straw in Adamawa region than the North West region. Pedological local construction materials include lateritic soils (ferruginous or clayey), harplan, sandy clay and sandy clay soil while geological local construction materials include volcanic, plutonic and metamorphic rocks. Many sites of these geological materials are suitable for the rock quarry plant. Adamawa region also contains sedimentary rocks constituted by metamorphic conglomerate and sandstones. Two main types of residential homes are constructed with these local construction materials in these regions of Cameroon. These include huts and houses.

关键词： Local Construction Materials Typology Adamawa and North-West Regions Cameroon

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Epididymis-specific lipocalin promoters

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Asian Journal of Andrology 2007年第4期9卷 515-521页

作者： Kichiya Suzuki Xiuping Yu Pierre Chaurand Yoshihiko Araki Jean-jacques Lareyre richard M. Caprioli Marie-Claire Orgebin-Crist Robert J. Matusik Department of Obstetrics and Gynecology Tohoku University Graduate School of Medicine Sendai 980-8574 Japan Departments of Urologic Surgery Vanderbilt University School of Medicine Nashville Tennessee 37232 USA Departments of Biochemistry Vanderbilt University School of Medicine Nashville Tennessee 37232 USA Departments of Obstetrics and Gynecology Vanderbilt University School of Medicine Nashville Tennessee 37232 USA Departments of Cell and Developmental Biology Vanderbilt University School of Medicine Nashville Tennessee 37232 USA Departments of Mass Spectrometry Research Center and Vanderbilt University School of Medicine Nashville Tennessee 37232 USA Departments of Center for Reproductive Biology Research Vanderbilt University School of Medicine Nashville Tennessee 37232 USA

Our goal is to decipher which DNA sequences are required for tissue-specific expression of epididymal genes. At least 6 epididymis-specific lipocalin genes are known. These are differently regulated and regionalized in the epididymis. Lipocalin 5 （Lcn5 or mE-RABP） and Lipocalin 8 （Lcn8 or mEP17） are homologous genes belonging to the epididymis-specific lipocalin gene cluster. Both the 5 kb promoter fragment of the Lcn5 gene and the 5.3 kb promoter fragment of the Lcn8 gene can direct transgene expression in the epididymis （Lcn5 to the distal caput and Lcn8 to the initial segment）, indicating that these promoter fragments contain important cis-regulatory element（s） for epididymisspecific gene expression. To define further the fragments regulating gene expression, the Lcn5 promoter was examined in transgenic mice and immortalized epididymal cell lines. After serial deletion, the 1.8 kb promoter fragment of the Lcn5 gene was sufficient for tissue-specific and region-specific gene expression in transgenic mice. Transient transfection analysis revealed that a transcription factor forkhead box A2 （Foxa2） interacts with androgen receptor and binds to the 100 bp fragment of the Lcn5 promoter between 1.2 kb and 1.3 kb and that Foxa2 expression inhibits androgen-dependent induction of the Lcn5 promoter activity. Immunohistochemistry indicated a restricted expression of Foxa2 in the epididymis where endogenous Lcn5 gene expression is suppressed and that the Foxa2 inhibition of the Lcn5 promoter is consistent with the lack of expression of Lcn5 in the corpus and cauda. Our approach provides a basic strategy for further analysis of the epididymal lipocalin gene regulation and flexible control of epididymal function. （Asian J Androl 2007 July; 9： 515-521）

关键词： androgen epididymis gene cluster gene evolution gene regulation lipocalin transcription factor

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A new hemostatic agent composed of Zn^(2+)-enriched Ca^(2+)alginate activates vascular endothelial cells in vitro and promotes tissue repair in vivo

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Bioactive Materials 2022年第12期7卷 368-382页

作者： Anne-Charlotte Ponsen richard Proust Sabrina Soave Françoise Mercier-Nom´e Isabelle Garcin Laurent Combettes Jean-jacques Lataillade Georges Uzan INSERM UMRS-MD 1197 Universit´e Paris-SaclayInstitut Andr´e LwoffHˆopital Paul BrousseVillejuifFrance Plateforme d’Histologie Immunopathologie de Clamart(PHIC) Universit´e Paris-SaclayINSERMCNRSInstitut Paris Saclay d’Innovation Th´erapeutiqueChˆatenay-MalabryFrance Universit´e Paris-Saclay INSERMInflammationMicrobiome and ImmunosurveillanceClamartFrance INSERM UMRS 1174 Universit´e Paris-SaclayOrsayFrance Centre de Transfusion Sanguine des Arm´ees ClamartFrance

To control capillary bleeding, surgeons may use absorbable hemostatic agents, such as Surgicel® and TachoSil®. Due to their slow resorption, their persistence in situ can have a negative impact on tissue repair in the resected organ. To avoid complications and obtain a hemostatic agent that promotes tissue repair, a zinc-supplemented calcium alginate compress was developed: HEMO-IONIC®. This compress is non-absorbable and is therefore removed once hemostasis has been achieved. After demonstrating the hemostatic efficacy and stability of the blood clot obtained with HEMO-IONIC, the impact of Surgicel, TachoSil, and HEMO-IONIC on cell activation and tissue repair were compared (i) in vitro on endothelial cells, which are essential to tissue repair, and (ii) in vivo in a mouse skin excision model. In vitro, only HEMO-IONIC maintained the phenotypic and functional properties of endothelial cells and induced their migration. In comparison, Surgicel was found to be highly cytotoxic, and TachoSil inhibited endothelial cell migration. In vivo, only HEMO-IONIC increased angiogenesis, the recruitment of cells essential to tissue repair (macrophages, fibroblasts, and epithelial cells), and accelerated maturation of the extracellular matrix. These results demonstrate that a zinc-supplemented calcium alginate, HEMO-IONIC, applied for 10 min at the end of surgery and then removed has a long-term positive effect on all phases of tissue repair.

关键词： Hemostatic agent Alginate Surgery Hemostasis Endothelial cells Tissue repair

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An Alternative Model to Radon Transform for Gamma Ray Emission Tomography

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Advances in Molecular Imaging 2017年第2期7卷 13-47页

作者： Christian Jeanguillaume richard Simonnet Christine Cavaro-Menard Abdelha Douiri Ines Bouali Jean jacques Loeb LARIS Laboratoire Angevin de Recherche en Ingenierie des Systemes Universite d’Angers Angers France Direction Generale de l’Armement Techniques Terrestres Bourges France King College London London United Kingdom LAREMA Laboratoire Angevin de Recherche en Mathematiques Universite d’Angers Angers France

The Radon transform fits badly Single Photon Emission Tomography (SPECT). However, Thin Holes Collimator (THC) and Radon model are widely used. The CACAO project has been proposed to enhance the quality of SPECT images. CACAO is a short hand notation for computer aided collimation tomography. The main idea of this project is to use collimators with much larger holes to increase the sensitivity, and slightly longer holes to increase the spatial resolution. The acquisition sequence includes a translation. The Radon projection is replaced by a 2D sum. A dedicated reconstruction algorithm has been developed. If the physical advantage of the project in terms of sensitivity and spatial resolution is generally admitted, a question remains unanswered: Would the ill-posedness of the inverse problem ruin the quality of the reconstructed images? In this article, a representation of the 2D direct problem matrix is derived. This allows us to compare the two inverse problems (CACAO versus THC). The condition number was used for this comparison. We studied the variation of these condition numbers with several parameters. For a proper set of parameters, the CACAO inverse problem may appear easier to solve and more accurately than the THC one.

关键词： Radon Transform Tomography SPECT Large and Long Hole Collimators Inverse Problems

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