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Optimization of Cellulose Nanocrystal Isolation from Ayous Sawdust Using Response Surface Methodology

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Journal of Materials Science and Chemical Engineering 2024年第1期12卷 36-55页

作者： Tchigo Alifa Hamida Aminatou Oumar Said jean-bosco Tchatchueng Department of Chemical Engineering School of Chemical Engineering and Mineral Industries University of Ngaoundere Ngaoundere Cameroon Department of Applied Chemistry National Advanced School of Agro-Industrial Sciences University of Ngaoundere Ngaoundere Cameroon Department in Charge of Coordination and Valorisation of Research National Advanced School of Engineering University of Yaounde 1 Yaounde Cameroon

This study focuses on the extraction of cellulose nanocrystals (CNC), from microcrystalline cellulose (MCC), derived from Ayous sawdust. The process involves multiple steps and a large amount of chemical products. The objective of this research was to determine the effects of factors that impact the isolation process and to identify the optimal conditions for CNC isolation by using the response surface methodology. The factors that varied during the process were the quantity of MCC, the concentration of sulfuric acid, the hydrolysis time and temperature, and the ultrasonic treatment time. The response measured was the yield. The study found that with 5.80 g of microcrystalline cellulose, a sulfuric acid concentration of 63.50% (w/w), a hydrolysis time of 53 minutes, a hydrolysis temperature of 69˚C, and a sonication time of 19 minutes are the ideal conditions for isolation. The experimental yield achieved was (37.84 ± 0.99) %. The main factors influencing the process were the sulfuric acid concentration, hydrolysis time and temperature, with a significant influence (p < 0.05). Infrared characterization results showed that nanocrystals were indeed isolated. With a crystallinity of 35.23 and 79.74, respectively, for Ayous wood fiber and nanocrystalline cellulose were observed by X-ray diffraction, with the formation of type II cellulose, thermodynamically more stable than native cellulose type I.

关键词： Ayous Sawdust Lignocellulosic Waste Isolation Cellulose Nanocrystals Optimization Response Surface Methodology

Epidemiological and Computed Tomography Aspects of Facial Trauma at Kira Hospital in Bujumbura

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Open Journal of Radiology 2024年第2期14卷 83-91页

作者： Sébastien Manirakiza jean Marie Banziriyubusa Stany Harakandi Patrice Barasukana Chantal Murekatete Daniel Nduwayo jean bosco Bizimana Léopold Nzisabira Department of Radiology Teaching Hospital of Kamenge Bujumbura Burundi Department of Anesthesia and Resuscitation Teaching Hospital of Kamenge Bujumbura Burundi Department of Internal Medicine (Neurology) Teaching Hospita lof Kamenge Bujumbura Burundi Department of Surgery (Neurosurgery) Teaching Hospital of Kamenge Bujumbura Burundi

Background: Maxillofacial trauma affects young adults more. The injury assessment is difficult to establish in low-income countries because of the imaging means, particularly the scanner, which is poorly available and less financially accessible. The aim of this study is to describe the epidemiological profile and the various tomodensitometric aspects of traumatic lesions of the face in patients received in the Radiology department of Kira Hospital. Patients and methods: This is a descriptive retrospective study involving 104 patients of all ages over a period of 2 years from December 2018 to November 2019 in the medical imaging department of KIRA HOSPITAL. We included in our study any patient having undergone a CT scan of the head and presenting at least one lesion of the facial mass, whether associated with other cranioencephalic lesions. Results: Among the 384 patients received for head trauma, 104 patients (27.1% of cases) presented facial damage. The average age of our patients was 32.02 years with extremes of 8 months and 79 years. In our study, 87 of the patients (83.6%) were male. The road accident was the circumstance in which facial trauma occurred in 79 patients (76% of cases). These injuries were accompanied by at least one bone fracture in 97 patients (93.3%). Patients with fractures of more than 3 facial bones accounted for 40.2% of cases and those with fractures of 2 to 3 bones accounted for 44.6% of cases. The midface was the site of the fracture in 85 patients (87.6% of cases). Orbital wall fractures were noted in 57 patients (58.8% of cases) and the jawbone was the site of a fracture in 50 patients (51.5% of cases). In the vault, the fractures involved the extra-facial frontal bone (36.1% of cases) and temporal bone (18.6% of cases). Cerebral contusion was noted in 41.2% of patients and pneumoencephaly in 15.5% of patients. Extradural hematoma was present in 16 patients and subdural hematoma affected 13 patients. Conclusion: Computed tomography is

关键词： Road Accident CT-Scan Facial Trauma

Bithalamic Ischemic Stroke in Sickle Cell Patient at the Kamenge University Hospital in Burundi: Case Report

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Open Journal of Medical Imaging 2024年第2期14卷 72-78页

作者： Sébastien Manirakiza Daniel Nduwayo Patrice Barasukana Chantal Murekatete jean bosco Bizimana Alice Ndayishimiye Léopold Nzisabira Hélène Bukuru Department of Radiology Kamenge University Hospital Center University of Burundi Bujumbura Burundi Department of Internal Medicine Neurology Kamenge University Hospital Center University of Burundi Bujumbura Burundi Department of Surgery Neurosurgery Kamenge University Hospital Center University of Burundi Bujumbura Burundi Department of Pediatrics Kamenge University Hospital Center University of Burundi Bujumbura Burundi

Aim: To describe the clinical and radiological diagnostic for a sickle cell patient who got a bithalamic vasculature accident. Observation: This was a 4-year-old female child admitted to the pediatric ward for convulsive seizures in a feverish context. The physical examination did not find signs of meningeal irritation. The effective workup including thick gout, lumbar puncture, complete blood count, and C reactive protein was normal. An electrocencephalogram was not performed due to lack of availability of the device. Based on clinical data and the fact that Burundi is an area of high malaria prevalence, antimalarial and anticonvulsant treatment has been started. An alteration of consciousness (the Glasgow score of 7) had motivated a CT scan. Bithalamic hypodensities in favor of a vascular accident have been demonstrated. Etiological investigation revealed homozygous sickle cell disease ss during hemoglobin electrophoresis. The final evolution has been characterized by a return to normal consciousness. Conclusion: The complexity of the clinical picture following occlusion of Percherons artery makes it difficult to diagnose. Sickle cell disease may favour the occurrence of ischaemic lesions. Cerebral imaging enables the diagnosis to be made with certainty and avoids delays in treatment.

关键词： Stroke Bithalamic Infarction Sickel Cell Percheron Artery

Traditional Healer’s Medicinal Practice Survey and Clinical Evidence Assessment of “YIKI”: An Antimalarial Phytomedicine Recipe from Bobo-Dioulasso, Burkina Faso

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Pharmacology & Pharmacy 2024年第7期15卷 248-267页

作者： Zachari Kabre Rakiswende Serge Yerbanga Aminata Fofana Roland Nâg-Tiero Meda Anyirekun Fabrice Some Alassane Haro Natacha A. J. A. Boro Fazhira B. Ye Benjamin Kouliga Koama Sami Eric Kam Eliasse Zongo Hadidjatou Belèm Windmi Kagambèga Florence Fournet Georges A. Ouedraogo jean-bosco Ouedraogo Institut de Recherche en Sciences de la Sant Direction Rgionale de lOuest Bobo-Dioulasso Burkina Faso Laboratoire de Recherche et dEnseignement en Sant et Biotechnologies Animales Universit Nazi BONI Bobo-Dioulasso Burkina Faso Institut des Sciences et Techniques Bobo-Dioulasso Burkina Faso Laboratoire de Recherche en Bactriologie INSP/Centre MURAZ Bobo-Dioulasso Burkina Faso Maladies Infectueuses et Vecteurs: Ecologie Gntique Evolution et Contrle (MIVEGEC) Institut de Recherche pour le Dveloppement Universit de Monpellier Montpellier France

YIKI is an antimalarial phytomedicine used by a traditional healer to treat malaria in Bobo-Dioulasso. However, there is no scientific evidence to support its use by local populations. The aim of this study was to identify the medicinal practices of the healer holder of YIKI and assess the clinical evidence of its phytomedicine in the uncomplicated malaria treatment. Ethnomedical survey based on a semi-structured and open questionnaire was conducted from October to December 2019 with the healer. Malaria knowledge and diagnosis methods, patient treatment and monitoring, and recipe formulation steps were surveyed. Moreover, thick and thin blood smears were taken, haemoglobin levels and temperature of consenting patients were measured before treatment, mid-treatment and at the end of treatment. The survey revealed that the healer has a good knowledge of malaria symptoms and his diagnosis is based on observation and physical examination of patients. The healer’s malaria diagnosis was rudimentary and had accuracy problems, with only 62.79% of malaria cases confirmed by microscopy. The formulation of YIKI and its use to treat malaria follow a standard process for plant harvesting, powder quantities and posology, but do not use any reproducible parameters for dose adjustment. Forty-three patients diagnosed and treated by the healer participated in the study. Laboratory results revealed 27 Plasmodium falciparum infection cases, including 2 with parasitaemia ≥ 200,000 p/µl blood. 25 patients were selected for therapeutic evidence assessment. There was a 48% elimination of parasites, a 28% parasitaemia decrease without complete cure, with gametocytogenesis in some patients, and a 24% parasitaemia increase. Haemoglobin and temperature results suggested that YIKI was not cytotoxic and reduced fever. Encouraging preliminary results have been obtained, but in view of the low number of patients, further YIKI efficacy and toxicity studies will be necessary for patient safety.

关键词： Antimalarial-Phytomedicine Efficacy Traditional Practices Bobo-Dioulasso

Geochemical characterization of the metasedimentary rocks of the Yaounde Group within the southernmost North Equatorial tectonic belt:insights into geodynamic evolution

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Acta Geochimica 2023年第6期42卷 1017-1034页

作者： Simon Pierre Mbola Ndzana Moise Christian Balla Ateba Germain Marie Monespérance Mboudou Moussa Nsangou Ngapna jean Paul Sep Nlongang Solange Ipan Moise Bessong jean bosco Olinga Joseph Mvondo Ondoa Sébastien Owona Paul Bilong Department of Earth Sciences Faculty of ScienceUniversity of YaoundéIP.O.Box:812Yaounde´Cameroon Institute for Geological and Mining Research P.O.Box:4110NlongkakYaounde´Cameroon Department of Earth Sciences Faculty of ScienceUniversity of DoualaP.O.Box:24157DoualaCameroon Department of Geology Faculty of ScienceThe University of BueaP.O.Box:67BueaCameroon

The Proterozoic metasedimentary rocks of the Yaounde Group on the northern edge of the Congo Shield in Central Africa were investigated to understand their provenance and depositional ***,geochemistry,and field evidence helped to subdivide the metasediments into paragneiss,mica schist,chlorite schist,and quartzite which were derived from greywacke,shale,quartz arenite,litharenite *** are immature with some mature samples,moderately weathered and reworked Neo-and Post-Archean *** earth element signatures(Chondrite Eu/Eu^(*)≤1),enrichment of light rare earth elements over the heavy ones,and the La/Sc ratio(>0.7)are compatible with those of the intermediate and felsic sources from the upper continental *** metasediments were deposited in the continental arc setting and have evolved during Proterozoic times according to the Wilson cycle to form the West Gondwana including NE Brazil.

关键词： West Gondwana North Equatorial orogenic belt Yaounde Group Neoproterozoic basin Geochemistry of metasedimentary rocks Geodynamic evolution

Neuro-fuzzy and model-based motion control for mobile manipulator among dynamic obstacles

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Science in China(Series F) 2003年第1期46卷 14-30页

作者：魏武 jean bosco Mbede 黄心汉张毅 Department of Automation Tsinghua University Departement des Genies Industrie Universit de Yaound I Ecole Nationals Superieure Polytechnique Department of Control Science and Engineering Huazhong University of Science and Technology

This paper focuses on autonomous motion control of a nonholonomic platform with a robotic arm, which is called mobile manipulator. It serves in transportation of loads in imperfectly known industrial environments with unknown dynamic obstacles. A union of both procedures is used to solve the general problems of collision-free motion. The problem of collision-free motion for mobile manipulators has been approached from two directions, Planning and Reactive Control. The dynamic path planning can be used to solve the problem of locomotion of mobile platform, and reactive approaches can be employed to solve the motion planning of the arm. The execution can generate the commands for the servo-systems of the robot so as to follow a given nominal trajectory while reacting in real-time to unexpected events. The execution can be designed as an Adaptive Fuzzy Neural Controller. In real world systems, sensor-based motion control becomes essential to deal with model uncertainties and unexpected obstacles.

关键词： autonomous mobile manipulators dynamic obstacle avoidance dynamic path planning model and sensor-based control neuro-fuzzy controller nonholonomic and redundant systems.

Starch Metabolism in Plant and Its Applications in Food Industry

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Advances in Biological Chemistry 2023年第4期13卷 111-127页

作者： Fabien Nsanzabera Evangeline Irakoze Alexis Manishimwe Aimable Mwiseneza jean bosco Nsengiyumva Fabien Nkurikiyimana Department of Education in Sciences Faculty of Education University of Technology and Arts of Byumba (UTAB) Byumba Rwanda African Center of Excellence in Innovative Teaching and Learning Mathematics and Science (ACE-ITLMS) College of Education University of Rwanda Kayonza Rwanda

Starch, a polymer of sugars in plants, is widely used in various industries due to its properties. It is synthesized through ADP-glucose formation and enzyme-mediated processes. Starch is formed during the day and broken down into sugars at night, which are then transported and converted back to starch in storage tissues. This review explores starch metabolism pathways and its role in the food industry, providing valuable insights on energy storage in plants.

关键词： Starch Metabolism Gelatinization Retrogradation Starch Biosynthesis Starch Degradation

Nurses’ Knowledge, Attitudes and Practice regarding Pressure Ulcers Prevention and Treatment

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Open Journal of Nursing 2022年第5期12卷 316-333页

作者： Edouard Niyongabo Emmanuel Gasaba Pascal Niyonsenga Marius Ndayizeye jean bosco Ninezereza Désiré Nsabimana Annonciate Nshimirimana Schadrypeluth Abakundanye Faculty of Health Sciences Hope Africa University Bujumbura Burundi Department of Public Health Sciences National Institute of Public Health Bujumbura Burundi

Pressure ulcers (PU) are one of the most common hospital-acquired problems that occur in patients with mobility limitations. Such wounds can produce pain and deterioration of the underlying condition. Sometimes, they can be life-threatening, and their treatment can impose a financial burden on both the patient’s family and society. Nurses’ knowledge, attitude, and practice are the most important weapons to fight this preventable burden of PU among patients with impaired mobility. The purpose of this study was to assess nurses’ knowledge, attitude, and practice regarding PU prevention and treatment at Clinique Prince Louis Rwagasore (CPLR) in Bujumbura, Burundi. A cross-sectional study design was used. Convenience sampling was used to invite all 28 qualified nurses and nurses’ aids who work in the services where critically ill patients are admitted to participate. A questionnaire was created, and underwent evaluation of face validity before using it to collect data which was analysed using SPSS 21.0. Results revealed that nurses’ knowledge and practice scores were low as participants scored less than 50% on the six knowledge items and the six practice items. However, the attitude scores were greater than 65% on the five items used to evaluate attitude. A strong negative correlation was found between nurses’ knowledge and their attitude scores (r = ?0.479, p = 0.015). Education level was negatively associated with nurses’ knowledge and practice scores of PU prevention and treatment. A high attitude score did not correlate with a higher practice score which might be explained by low knowledge scores (less than 50% on knowledge items). Continuous professional development (CPD) was recommended to improve nurses’ knowledge scores and implementation of PU preventive practices at CPLR.

关键词： Pressure Ulcers Nurses Prevention Treatment Knowledge Attitude Practice

New Optimal Pivot Rule for the Simplex Algorithm

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Advances in Pure Mathematics 2016年第10期6卷 647-658页

作者： jean bosco Etoa Etoa Department of Economic and Management Sciences University of Yaounde II Soa Cameroon

The purpose of this paper is to introduce a new pivot rule of the simplex algorithm. The simplex algorithm first presented by George B. Dantzig, is a widely used method for solving a linear programming problem (LP). One of the important steps of the simplex algorithm is applying an appropriate pivot rule to select the basis-entering variable corresponding to the maximum reduced cost. Unfortunately, this pivot rule not only can lead to a critical cycling (solved by Bland’s rules), but does not improve efficiently the objective function. Our new pivot rule 1) solves the cycling problem in the original Dantzig’s simplex pivot rule, and 2) leads to an optimal improvement of the objective function at each iteration. The new pivot rule can lead to the optimal solution of LP with a lower number of iterations. In a maximization problem, Dantzig’s pivot rule selects a basis-entering variable corresponding to the most positive reduced cost;in some problems, it is well-known that Dantzig’s pivot rule, before reaching the optimal solution, may visit a large number of extreme points. Our goal is to improve the simplex algorithm so that the number of extreme points to visit is reduced;we propose an optimal improvement in the objective value per unit step of the basis-entering variable. In this paper, we propose a pivot rule that can reduce the number of such iterations over the Dantzig’s pivot rule and prevent cycling in the simplex algorithm. The idea is to have the maximum improvement in the objective value function: from the set of basis-entering variables with positive reduced cost, the efficient basis-entering variable corresponds to an optimal improvement of the objective function. Using computational complexity arguments and some examples, we prove that our optimal pivot rule is very effective and solves the cycling problem in LP. We test and compare the efficiency of this new pivot rule with Dantzig’s original pivot rule and the simplex algorithm in MATLAB environment.

关键词： Linear Programming Simplex Algorithm Pivot Rules Optimal Pivot Rule