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Identification of major sources controlling groundwater geochemistry in Mount Makabaï in the Far-North of Cameroon(the northernmost part of the pan-African Belt)

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Acta Geochimica 2023年第2期42卷 266-289页

作者： Merlin GountiéDedzo DésiréTsozué Amidou Kpoumié Aubin Nzeugang Nzeukou Department of life and Earth Sciences Higher Teachers’Training CollegeUniversity of MarouaP.O.Box.55MarouaCameroon Department of Earth Sciences Faculty of ScienceUniversity of MarouaP.O.Box.814MarouaCameroon

The present work focuses on the volcanic basement rock geochemistry of Mount Makabaï(MarouaCameroon city)in relation to groundwater *** were centered on an approach involving an association of several methods such as geological cartography,hydrogeology,and *** rock samples,four disturbed soil samples,three undisturbed soil samples,and 20 samples of groundwater in 10 wells were collected during fieldwork and prepared for laboratory *** exhibit porphyritic,aphyric,and subaphiric *** phenocryst phases are mainly olivine,clinopyroxene,and *** on whole rock major element chemical compositions,the Makabaï samples,plotted on Na_(2)O+K_(2)O versus SiO_(2)diagram,are mugearite,hawaiite,and *** ratio of(MgO+CaO)/(Na_(2)O+K_(2)O)exceeds unity and shows dominance of alkaline Earth metals(MgO:2.99-4.48%;CaO:6.19-9.80%)relatively to alkali metals(Na_(2)O:2.27-4.46%;K_(2)O:2.09-2.51%).Exchangeable base contents are high,mostly represented by Ca and Mg,whose contents vary from 14.6 to 35.28 cmol(+)kg^(-1)and from 3.28 to9.48 cmol(+)kg^(-1)*** CECclayis likewise high,fluctuating between 116.80 and181.38 cmol(+)kg^(-1),values in line with the presence of 2:1 clay minerals represented in the study area by *** the water samples,the Ca2+and Na+contents are generally higher than K^(+)and Mg^(2+),reflecting the relative abundance of Na_(2)O and CaO oxides to K_(2)O and MgO oxides in rocks where different waters were *** waters of Makabaï are acidic to neutral(6.3≤pH≤7.4)and weakly to highly mineralized(110.0≤EC≤1190.0μS/cm).Hydro-geochemical classification by using the piper diagram revealed two water types:(1)CaMg-HCO_(3)(40%)and(2)CaMg-Cl or CaMg-SO4(60%).The average content of ions in all the analyzed samples was HCO_(3)^(-)>>NO_(3)^(-)>SO_(4)^(2-)>Cl-for anions and Ca^(2+)>>Mg^(2+)>Na^(+)>K^(+)for *** mechanisms governing ionic constituents of groundwater in

关键词： Mount Makabaï-Maroua city Far-North Cameroon Bedrock minerals Groundwater-rock-soil interaction Crystalline basement

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lighting up aggregate emission of perylene diimide by leveraging polymerization-mediated through-space charge transfer and π-π stacking

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Science China Chemistry 2024年第12期67卷 4218-4233页

作者： Suiying Ye Désirée Füglistaller Tian Tian Anjay Manian Sudhir Kumar Celine Nardo Andrew J.Christofferson Salvy p.Russo Chih-Jen Shih Jean-Christophe leroux Yinyin Bao Institute of pharmaceutical Sciences Department of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 38093 ZurichSwitzerland Institute for Chemical and Bioengineering Department of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1-5/108093 ZurichSwitzerland ARC Centre of Excellence in Exciton Science School of ScienceRMIT UniversityMelbourneVictoria3001Australia School of Science STEM CollegeRMIT UniversityMelbourneVictoria 3001Australia

The molecular engineering of fluorescent organic/polymeric materials,specifically those emitting in the deep red to near-infrared spectrum,is vital for advancements in optoelectronics and *** diimide(pDI),a well-known fluorescent scaffold,offers high thermal and photophysical stability but suffers from fluorescence quenching in solid or aggregate states due to intenseπ-π*** mitigate this,simple and versatile methods for strong pDI aggregate emission without extensive synthetic demands are highly desirable but still ***,we report a straightforward strategy to enhance the solid-state emission of pDI by introducing certain degree of through-space charge transfer(TSCT)via controlled radical polymerization,which can efficiently distort the typical face-to-face pDI stacking,enabling greatly enhanced deep red *** is achieved by growing electron-donating star-shape styrenic(co)polymers from a multidirectional electron-accepting pDI *** incorporation of polycyclic aromatic monomers further shifted the emission into the near-infrared region,albeit with a reduced ***,the emission of the pDI-based TSCT polymers can be systematically manipulated by leveraging the balance between pDI stacking and the TSCT degree,as confirmed by both experimental study and theoretical *** approach circumvents complex synthetic procedures,offering highly emissive materials with large Stokes shifts and showing broad potential for optoelectronic technology.

关键词： through-space charge transfer controlled radical polymerization solid-state emission perylene diimide

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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 Djakba Basga DésiréTsozue Jean pierre Temga Jules Balna Jean pierre Nguetnkam 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 kg-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 kg-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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Evaluation of effectiveness of polymer coatings in reducing blastinduced deformation of steel plates

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Defence Technology（防务技术） 2021年第6期17卷 1895-1904页

作者： Damith Mohotti p.l.N.Fernando Dakshitha Weerasinghe Alex Remennikov School of Engineering and Information Technology The University of New South WalesCanberraACT2600Australia Department of Civil Engineering Faculty of EngineeringGeneral Sir John Kotelawala Defence UniversityRatmalanaSri Lanka School of Civil Engineering Faculty of EngineeringThe University of SydneyDarlingtonNSW2006Australia Centre for Infrastructure protection and Mining Safety University of WollongongWollongongNSW2522Australia

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads,has gained significant *** main objective of this study is to investigate the influence of a polyurea coating towards the blast-induced response in steel *** such,polyurea coated steel plates were tested under near-field blast loads,produced by the detonation of 1 kg of spherical nitromethane charges,at a standoff distance of 150 *** steel(XlERplATE 350)and high-strength steel(BIS80)plates with thicknesses of 10 mm were polyurea coated with thicknesses of 6 mm and 12 mm on either the front(facing the charge)or the back *** deformation profiles were measured using 3D *** simulations were performed using the non-linear finite element code *** strain-dependent behaviour of the steel and polyurea were represented by Johnson-cook and Money-Rivlin constitutive models,*** numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the polyurea *** results indicate that back face coating contributes towards an approximately 20%reduction in the residual deformation as well as the absence of melting of the polyurea layer,while the front-face coating can be used a means of providing additional standoff distance to the steel plates.

关键词： polyurea coating Near-field blast lS-DYNA plate deformation AlE

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pattern of potential laboratory Markers for COVID-19 in Eastern Sudan

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Open Journal of Epidemiology 2024年第3期14卷 508-516页

作者： Nazik sir El Khatim Bakhit Suliman Mohammed Omer Abaker Gibreel Mervat sir El Khatim Bakhit Suliman Department of Clinical Chemistry College of Medical Laboratory Science Eastern Sudan University of Medical Science and Technology Port Sudan Sudan Dean of the Secretariat of Academic Affairs Port Sudan Ahlia University Port Sudan Sudan Cardiology Department Cath Lab Fujaira Hospital Fujaira UAE

Background: Coronavirus disease 2019 (COVID-19) is a recent global health crisis. One of the major issues of COVID-19 is its unpredictable manifestations and serious outcomes. Many hematological parameters are thought to change dramatically during the course of the disease. These include white blood cells, red blood cells, and platelets. This study aimed at evaluating certain laboratory results;peripheral blood lymphopenia, relative neutrophilia, high neutrophil-lymphocyte ratio, and elevated C-reactive protein as potential laboratory markers of COVID-19 in Eastern Sudanese patients. Methods: We, retrospectively, aimed at the evaluation of peripheral blood leucocytes count, neutrophil-lymphocyte ratio NlR and C-reactive protein (CRp) levels in confirmed COVID-19 eastern Sudanese patients during the course of the disease. Results: The mean total leucocytes count, % neutrophils count, absolute neutrophils count and C-reactive protein (CRp) were significantly higher (p. value = 0.000) in COVID-19 patients than in the control group while the mean % lymphocytes count and % mixed cells count were found to be significantly lower in COVID-19 patients than in the control group (p. value 0.000). Conclusion: peripheral blood leucocyte alterations (simultaneous presence of lymphopenia, relative neutrophilia and high neutrophil lymphocyte ratio (NlR) along with elevated CRp levels may be valuable biomarkers associated with COVID-19 in port Sudan city, Red Sea state, Sudan. These markers might be important in prediction, inspection of disease progression and prognosis.

关键词： COVID-19 SARS 2 WBCs CRp NlR port Sudan

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掺硼金刚石阳极电氧化和电芬顿工艺处理真实水体中低含量药物的研究(英文)

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电化学 2013年第4期19卷 300-312页

作者： Ignasi sirés JoséAntonio Garrido Enric Brillas laboratori d'Electroquímica dels Materials i del Medi Ambient Departament de Química FísicaFacultat de QuímicaUniversitat de BarcelonaMartíi Franquès 1-1108028 BarcelonaSpain

本文报告了采用掺硼金刚石阳极(BDD)电氧化和电芬顿工艺处理真实水体中注入含有少量药物残留物的单组分和多组分溶液(即1 mg.l-1对乙酰氨基酚和(或)1 mg.l-1水杨酸,pH=3)的研究结果.以恒定电流密度方式在BDD/pt电解池中进行电氧化,而在B... 详细信息

本文报告了采用掺硼金刚石阳极(BDD)电氧化和电芬顿工艺处理真实水体中注入含有少量药物残留物的单组分和多组分溶液(即1 mg.l-1对乙酰氨基酚和(或)1 mg.l-1水杨酸,pH=3)的研究结果.以恒定电流密度方式在BDD/pt电解池中进行电氧化,而在BDD/空气扩散电解池中进行电芬顿,从而在阴极电生H2O2.结果表明,由于乙酰氨基酚和水杨酸均与溶液中氯离子氧化所产生的活性氯物种发生反应,因此,电氧化处理真实水体中两种药物的降解要比超纯水中添加0.05 mol.l-1Na2SO4快.这种含氯氧化剂的反应活性甚至超过了阳极形成的有限的羟基活性基,提高电流密度大大加速了两种污染物的消除.在真实水体自然碱性pH下得到了类似的结果.当电氧化处理两种药物的混合物时,两种药物上面产生的氧化剂的竞争作用,导致药物的降解变慢,只有电芬顿处理真实水体时药物的降解才稍微加快,这是由于H2O2与Cl-的反应,生成了反应活性弱得多的含氯活性基,从而抑制了电生的H2O2和添加的Fe2+之间发生的芬顿反应所形成的同相羟基活性基的累积.对于添加了药物的真实水体,在较高的电流密度下电氧化可得到较好的天然有机物成分(NOM)矿化度,且添加0.05 mol.l-1Na2SO4效果会更好.虽然在药物溶液的电氧化中检测出微量的氧化副产物,如对苯醌、NO3-和NH4+离子,但在本研究条件下无法去除真实水体中所含有的氮基化合物.

关键词：掺硼金刚石阳极电氧化电芬顿药物真实水体水杨酸

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pre-operative radiochemotherapy of locally advanced rectal cancer

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World Journal of Gastroenterology 2003年第4期9卷 717-720页

作者： Xiao-Nan Sun Qi-Chu Yang Jian-Bin Hu Department of Radiation Oncology,sir Run Run Shaw Hospital,College of Medicine,Zhejiang University,Hangzhou 310016,Zhejiang province,China Department of Radiation Oncology Sir Run Run Shaw Hospital College of Medicine Zhejiang University Hangzhou 310016 Zhejiang Province China. sunxiaonan@***

AIM: To evaluate results of pre-operative radiochemotherapy followed by surgery for 15 patients with locally advanced un-resectable rectal ***: 15 patients with advanced non-resectable rectal cancer were treated with pre-operative irriadiation of 40-46 Gy plus concomitant chemotherapy (5-FU+lV and 5′-DFuR) (RCS group). For comparison, 27 similar patients,treated by preoperative radiotherapy (40-50 Gy) plus surgery were served as control (RS group).RESUlTS: No radiochemotherapy or radiotherapy was interrupted and then was delayed because of toxicities in both groups. The radical resectability rate was 73.3% in the RCS group and 37.0% (p=0.024) in RS group. Sphincter preservation rates were 26.6% and 3.7% respectively (p=0.028). Sphincter preservation rates of lower rectal cancer were 27.3 % and 0.0 % respectively (p=0.014). Response rates of RCS and RS groups were 46.7 % and 18.5 %(p=0.053). The tumor downstage rates were 8 (53.3%)and 9 (33.3%) in these groups (p=0.206). The 3-year overall survival rates were 66.7 % and 55.6% (p=0.485), and the disease free survival rates were 40.1% and 33.2%(p=0.663). The 3-year local recurrent rates were 26.7%and 48.1% (p=0.174). No obvious late effects were found in either ***: High resectability is possible following preoperative radiochemotherapy and can have more sphincters preserved. It is important to improve the quality of the patients′ life even without increasing the survival or local control rates. preoperative radiotherapy with concomitant full course chemotherapy (5-Fu+lV and 5′-DFuR) is effective and safe.

关键词：局限性进展期直肠癌预处理放射化学疗法毒性反应临床疗效

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Study of Mass Spectra of Some Indole Derivatives

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American Journal of Analytical Chemistry 2016年第4期7卷 351-355页

作者： A. El Kihel M. Ahbala H. Sdassi H. Ait sir A. Mouzdahir p. Bauchat laboratoire de Chimie BioOrganique Faculté des Sciences El Jadida Morocco Ciblage et Auto-Assemblages Fonctionnels UMR 6226 Université de Rennes I Rennes Cédex France

In the work, a study of mass fragmentation routes by the electron-impact mass spectrometry data has been examined for two open chain intermediates of indole derivatives and two pyrroloquinolines. By the isolation of o... 详细信息

关键词： Indole Open-Chain Intermediate pyrroloquinoline Fragments

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The potential Application of <i>Syzygium aromaticum</i>and <i>Cymbopogon citratus</i>Essential Oils as Natural preservatives of Beef patties

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Food and Nutrition Sciences 2015年第3期6卷 374-385页

作者： Fabrice Bruno Siewe pierre Désiré Mbougueng léopold Ngoune Tatsadjieu Thierry Ngangmou Noumo Carl M. F. Mbofung Department of Food Science and Nutrition National School of Agro-Industrial Sciences University of Ngaoundere Ngaoundere Cameroon Department of process Engineering National School of Agro-Industrial Sciences University of Ngaoundere Ngaoundere Cameroon Department of Food Engineering and Quality Control University Institute of Technology University of Ngaoundere Ngaoundere Cameroon College of Technology University of Bamenda Bamenda Cameroon

The effect of essential oils from Syzygium aromaticum and Cymbopogon citratus on the lipid oxidation and microbial growth in beef patties was investigated in the present study. Essential oils were incorporated into the beef patties at 0.1% and 0.2% (w/w). The beef patties were then inoculated with cultures of E. coli and S. aureus and stored at 4°C. The control patties were processed without essential oil but inoculated with E. coli or S. aureus. The proximate composition, lipid oxidation and microbial counts were carried out after 7, 14, 21 and 28 days. Results showed that the incorporation of essential oils in beef patties did not significantly (p S. aromaticum at 0.2% reduced the E. coli growth by 1.48 log CFU/g and that of S. aureus by 6.52 log CFU/g while the incorporation of C. citratus at 0.2% reduced the E. coli growth by 1.21 log CFU/g and that of S. aureus by 1.4 log CFU/g after 28 days of storage. The pH measurement during the storage period showed a slight drop during the first 7 days of storage and an increase during the last 21 days in all samples. The sensory test of the beef patties showed that the consumers accepted patties formulated with the two essential oils. But the one made with 0.1% essential oil of S. aromaticum was the most accepted. The analysis of the color of beef patties between 0 and 28 days of storage revealed that the incorporation of essential oils retarded the degradation of the color of patties. Results obtained in the present study indicate the possibility of exploiting Syzygium aromaticum and Cymbopogon citratus essential oils to protect beef patties against lipid oxidation and microbial growth.

关键词： S. aromaticum C. citratus Essential Oil Beef patties lipid Oxidation Microbial Stability Escherichia coli Staphylococcus aureus

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双金属Au-CuO/CeO2催化二氧化碳加氢制甲醇催化性能研究

双金属Au-CuO/CeO2催化二氧化碳加氢制甲醇催化性能研究

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作者： Kimpouni Tongo Désirée Wager（王歌）大连理工大学

学位级别：硕士

随着工业的发展,大气中二氧化碳(CO2)含量的增加,导致全球变暖、气候变化和海洋酸化。因此,减少人为CO2排放是本世纪的主要挑战之一。甲醇是一种清洁能源,在交通、化工等领域有着广泛的应用。将CO加氢制备甲醇是减少CO排放、促进经济可... 详细信息

随着工业的发展,大气中二氧化碳(CO2)含量的增加,导致全球变暖、气候变化和海洋酸化。因此,减少人为CO2排放是本世纪的主要挑战之一。甲醇是一种清洁能源,在交通、化工等领域有着广泛的应用。将CO加氢制备甲醇是减少CO排放、促进经济可持续发展的一种有前景的研究方向。本论文旨在探讨载金量及金铜相互作用对甲醇选择性及催化剂物化性质的影响。因此,采用共浸渍法制备了一系列不同Au含量的CeO负载型双金属Au-Cu催化剂,并采用各种技术对催化剂的结构和还原行为进行了表征。在不同的温度和比反应物配比下进行了催化活性测定。此外,利用原位红外光谱研究了CO加氢制甲醇的吸附形态和反应途径。主要研究成果如下:(1)调控金含量研究催化剂结构和对CO加氢制甲醇催化性能的影响。制备Au/CeO、CuO/CeO和双金属(0.5 wt.%、1 wt.%、2 wt.%)Au-CuO/CeO催化剂,并对其催化CO加氢制甲醇进行了研究。研究发现,金的加入有利于铜粒子的分散和粒径的减小。此外,它还促进了氧空位的形成,特别是1 wt.%的Au-CuO/CeO2是最佳的载金催化剂,由于其通过增强氢溢出效应提高了氢解离的效率,表现出最高的甲醇选择性(T=240C,p=3 Mpa,S=29.6%)。(2)研究了Au-Cu相互作用的影响。结果表明,与单金属催化剂相比,这种相互作用通过提高氢溢出和甲醇选择性为氢的吸附和解离提供了场所。0.5 wt.%Au-CuO/CeO和2 wt.%Au-CuO/CeO的相互作用对氢吸附的改善作用不大。因此,1wt.%Au-CuO/CeO2的最佳催化性能可归因于该催化剂中金与铜的协同作用(3)采用原位漫反射红外傅里叶变换光谱(DRIFTS)技术研究了反应分子(CO和H)在活性试验压力(3 Mpa)下的吸附位置和反应途径。结果表明,在还原性载体CeO负载Au-CuO催化剂在CO加氢制甲醇反应中具有双位性,CO在CeO载体上被活化。与其它催化剂相比,1 wt.%Au-CuO/CeO催化剂表面甲氧基和甲酸盐物种的强度更高,表明其有利于氢的解离。反应路线为碳酸氢盐加氢形成甲酸,然后甲氧基,最后甲醇。

关键词：二氧化碳加氢甲醇金铜相互作用氢解离

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