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Engineering（科研） 2019年第12期11卷 819-827页

作者： Timothée Thierry Odi Enyegue Didier Fokwa eric flavien mbiakouo-djomo Ebenezer Njeugna Doctoral Unit of Engineering Sciences Laboratory of Mechanical Engineering ENSET University of Douala Douala Cameroon Department of Civil Engineering ENSET Douala University Douala Cameroon Department of Mechanical Engineering Douala University Douala Cameroon

We explore the parameters that influence the dynamics of water erosion. The method used is an experimental laboratory simulation, which consists of the quantitative evaluation of eroded masses as a function of slope, soil cohesion and rainfall intensity. A simulator was designed to have the ability to vary the slope of the terrain, as well as the rainfall intensity. The variation of the soil cohesion is obtained by compacting the soil under different pressures using a hydraulic press associated with the whole experimental device. The results obtained show that the device is a good tool to simulate in the laboratory the behavior of different soil under the action of rain;because these results are in agreement with existing models USLE, MUSLE and RUSLE [1] [2] [3] [4].

关键词： Water Erosion Mini-Rain Simulator Cohesion of a Soil Simulation Slope

Effects of Soil Compaction in the Fight against Unpaved Roads Degradation Due to Erosion Caused by Heavy Rain: Proposition of a Specific CBR Evaluation Model

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Engineering（科研） 2021年第3期13卷 95-104页

作者： Timothée Thierry Odi Enyegue eric flavien mbiakouo-djomo Hugues Tsanga Fabien Kenmogne Blaise Ngwem Bayiha Gilbert Tchemou Ebenezer Njeugna Didier Fokwa Laboratory of Mechanics Doctorate Unit of Engineering Sciences Doctorate School of Fundamental and Applied Sciences University of Douala Douala Cameroon Department of Rural Engeineering FASA University of Dschang Dschang Cameroon Civil Engineering Department Higher Technical Teacher’s Training College University oh Douala Douala Cameroon Mechanics Engineering Department Higher Technical Teacher’s Training College University oh Douala Douala Cameroon

Unpailt roads are generally subject to erosion, when they need to be bitumen, civil engineers need to know the geotechnical capabilities of the soil layers to be used as support, among these capabilities, for example, soil characteristics to withstand erosion. CBR has often been used to classify these soils according to their compaction. In this article, we propose a correlation between CBR and eroded soil mass through a simulator. Indeed, in this article we show that using a simulator, soils can be classified according to their ability to withstand water erosion, whether internal or external. Indeed it is shown that the mass of eroded soil is related to the compaction capacity of the soil just as the CBR also has. We study the effects and influence of soil compaction on the ability of an unpaved road to resist erosion caused by falling raindrops. To do this, lateritic soil is submitted to different compaction pressures. The compacted soil is then submitted to CBR test and rain fall through a mini rain simulator. Correlations between eroded soil masse and compaction pressure as well as CBR are derived. The study shows that the compaction reduces the erodibility and increases the bearing capacity of soil. The formula obtained is significant because we have a new way of evaluating soils in the laboratory.

关键词： Compaction Erosion Lateritic Soil Rain Drop Unpaved Roads

Determination of a Mathematical Model of Erosion Taking into Account the Intensity of Rainfall and Soil Slopes from the Global MNT Model

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Engineering（科研） 2022年第7期14卷 274-284页

作者： eric flavien mbiakouo-djomo Timothée Thierry Odi-Enyegue André Abanda Gilbert Tchemou Ulrich Florin Djiofack-Tiagho Denis Tcheukam-Toko Ngouffo Koukougnang Réné Didier Fokwa Ebénézer Njeugna Department of Rural Engineering FASA University of Dschang Dschang Cameroon Department of Civil Engineering ENSPD University of Douala Douala Cameroon Department of Mechanical Engineering College of Technology University of Buea Buea Cameroon Department of Civil Engineering ENSET Douala Cameroon Laboratory of Mechanics and Modeling of Physical Systems University of Dschang Dschang Cameroon

Our study is being carried out in the Wouri Estuary more precisely in the Nylon area, Douala. This area is influenced by abundant rainfall which promotes the phenomenon of rain erosion. This erosion contributes to the degradation of structures and soils. To better understand and predict this phenomenon of rainfall erosion, we set out to establish a mathematical model that takes into account precipitation and topography. To this end, the data collected in the field and in the laboratory made it possible. First, we graphically modeled the variation of the potential as a function of the intensity of rainfall and the slope of the ground. Next, we identified a mathematical model from cubic spline surface interpolation. Finally, we obtained the mathematical model which makes it possible to evaluate and predict the erosion potential. The results obtained allowed to have an erosion potential of 153.67 t/ha/year with field data and 153.94 t/ha/year with laboratory data. We compared the results obtained with those existing in the literature on the same study site. This comparison made it possible to validate the established mathematical model. This mathematical model is a decision support tool and can predict problems related to water, erosion and the environment.

关键词： Erosion Erosion Potential Mathematical Model Rainfall Intensity Soil Slope

Surgical Treatment of Chronic Constrictive Pericarditis in a Developing Country

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World Journal of Cardiovascular Surgery 2022年第11期12卷 281-191页

作者： Kouassi Antonin Souaga eric Koutoua Katché Yoboua Aimé Kirioua-Kamenan Jean Calaire Degré Kwadjau Anderson Amani Gnamien Randolph Niava Joseph Kouamé Paul Yapo Yapo Kouassi flavien Kendja Cardiovascular Surgery Department The Abidjan Heart Institute Abidjan C&#244te d’Ivoire Anesthesia and Intensive Care Department The Abidjan Heart Institute Abidjan C&#244te d’Ivoire

Background: Chronic constrictive pericarditis is a rare but serious clinical entity with a poor prognosis in the absence of surgical treatment. The purpose of this study was to report on our experience of subtotal anterior pericardectomy and analyze our surgical results. Results: We included 74 patients operated on for chronic constrictive pericarditis in our institution during the period from January 1985 to December 2020. There were 29 female and 45 male patients, with an average age of 28 years (range: 8 - 64 years). 36.5% of patients were in NYHA class III or IV. Physical signs were dominated by peripheral signs of right heart failure in 93.2% of cases. The surgical procedure was a subtotal anterior pericardectomy from the left to the right phrenic nerve, freeing the heart chambers and the large vessels. The surgical results were marked by a functional improvement in 82.4% of the cases. The postoperative complications were marked by a low cardiac output in 8.1% of the cases, a atrial fibrillation in 4.1% of the cases, a haemorrhage in 1.4% of the cases, a haemothorax in 2.7% of the cases. Perioperative mortality was 5.4% patients. The causes of death were low cardiac output in 50% of cases, hemorrhage in 25% of cases, and hepatocellular insufficiency in 25% of cases. We observed a mortality of 2.9% after an average follow-up of 5.17 years ± 4.76 years. All other survivors were asymptomatic and no re-intervention for recurrence was performed. Conclusions: Subtotal anterior pericardectomy was the technique we used for the treatment of chronic constrictive pericarditis. It allowed having satisfactory surgical results with a functional improvement and an acceptable morbidity.

关键词： Constrictive Pericarditis Subtotal Pericardectomy Result

Primary Cardiac Tumors Operated on in Côte d’Ivoire: They Are Almost All Myxomas

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World Journal of Cardiovascular Surgery 2023年第5期13卷 93-99页

作者： Yoboua Aimé Kirioua-Kamenan Jean Calaire Degré Koutoua eric Katché Katché Kouassi Antonin Souaga Kwadjau Anderson Amani Assoumou Lucien Asseke Ibrahim Junior Yeo Landry Kohou-Kone Kouassi flavien Kendja Cardiovascular Surgery Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire Department of Surgery and Surgical Specialties F&#233lix Houphou&#235t-Boigny University Abidjan C&#244te d’Ivoire Thoracic Surgery Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire Anesthesia and Intensive Care Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire

Objective: Through this surgical series, we present the epidemiological and anatomical-clinical aspects and the surgical results concerning patients operated on for a primary cardiac tumor at the Abidjan Heart Institute. Materials and Method: This is a retrospective descriptive study covering the period of January 1982 to December 2022, based on the medical records of patients operated on for a primary cardiac tumor at the Abidjan Heart Institute. Results: Twenty-seven (27) patients underwent surgery for a primary cardiac tumor, including 14 women and 13 men with a mean age of 41.5 years (range 19 - 76 years). The main circumstances of discovery were exertional dyspnea, palpitation and syncope or pseudo-syncope. The main site was the septal wall of the left atrium. The diagnosis of myxoma was confirmed by pathological examination of the surgical specimen in 96.3% (n = 24) of the patients and it was a malignant large cell immunoblastic lymphoma of the myocardium in 3.7% (n = 1) of the patients. The mean largest diameter was 46.1 mm. The postoperative course was marked by an ischaemic stroke (n = 1);recurrence of a left atrial myxoma 5 years after the first tumor removal (n = 1). Two cases of death were noted, one due to the evolution of immunoblastic large cell lymphoma and the other due to an extracorporeal circulation accident. Conclusion: Almost all primary cardiac tumors operated on in Abidjan are myxomas. The circumstances of the discovery of these cardiac tumors are multiple and varied but dominated by exertional dyspnea, palpitation and syncope. Whatever their histological type, primary cardiac tumors are serious affections, in view of the haemodynamic and rhythmic disorders they cause.

关键词： Cardiac Myxomas Primary Cardiac Tumors Tumor Removal

Axillary Vessels and Brachial Plexus Traumas in Abidjan: Lesional Aspects and Surgical Difficulties

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World Journal of Cardiovascular Surgery 2023年第5期13卷 85-92页

作者： Yoboua Aimé Kirioua-Kamenan Assoumou Lucien Asseke Jean Calaire Degré Koutoua eric Katché Ibrahim Junior Yeo Marc Hervé Kassi Zolé Cedrick Doh Kwadjau Anderson Amani Kouassi Antonin Souaga Kouassi flavien Kendja Cardiovascular Surgery Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire Department of Surgery and Surgical Specialties F&#233lix Houphou&#235t-Boigny University Abidjan C&#244te d’Ivoire Thoracic Surgery Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire Anesthesia and Intensive Care Department Abidjan Heart Institute Abidjan C&#244te d’Ivoire

Introduction-Objectives: Through the presentation of epidemiological, anatomo-clinical and surgical aspects, we report our experience in the management of traumatic axillary lesions. Materials and Methods: A descriptive retrospective study was based on the medical records of patients who suffered vascular axillary and/or brachial plexus trauma and who underwent surgical repair at the Abidjan Cardiology Institute from January 2008 to June 2022. Epidemiological, anatomo-clinical and surgical data were studied. Results: Thirty-four medical files belonging to 33 men and one woman, aged 32 on average, were collected. The circumstances of occurrence were dominated by the stab wound (n = 22). The combinations of injuries were as follows: associated involvement of the axillary artery and vein (n = 4);isolated involvement of axillary artery (n = 3);isolated involvement of the axillary vein (n = 2);associated involvement of the axillary artery and brachial plexus (n = 17);associated involvement of the axillary artery and vein and brachial plexus (n = 08). Anatomic lesions included acute arterial lesions (n = 29) and arteriovenous fistula (n = 1) and false aneurysms (n = 4). All patients were operated on under general anesthesia;vascular repair included direct suturing (n = 16), arterial and venous bypass using a long saphenous graft (n = 9), prosthetic arterial bypass (n = 5) and prosthetic flattening-graft (n = 4). Brachial plexus surgery consisted of an end-to-end anastomosis of each transected bundle in all cases (n = 25). The medium-term postoperative course was marked by success without functional sequelae in 88.24% of cases (n = 30) and by the persistence of distal paralysis of the thoracic limb after 6 months in 05.88% (n = 2) of all patients, i.e., 8% of patients who presented with brachial plexus injury. Conclusion: The concomitant surgical treatment of these axillary vascular and nerve lesions has given good results. However, if paralysis of the thoracic limb persis

关键词： Brachial Plexus Surgery Distal Paralysis of the Thoracic Limb False Aneurysms Flattening-Prosthetic Graft Traumatic Axillary Lesions

Surgical Myocardial Revascularization in a Sub-Saharan African Country: Indications and Results

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World Journal of Cardiovascular Surgery 2021年第11期11卷 95-103页

作者： Kouassi Antonin Souaga Gnamien Randolph Niava eric Koutoua Katché Kwadjau Anderson Amani Yoboua Aimé Kirioua-Kamenan Jean Calaire Degré Arnau Ekou Aka Roland N’guetta Joseph Kouamé Landry Kohou-Koné Yapo Paul Yapo Kouassi flavien Kendja Kouassi Michel Kangah Cardiovascular Surgery Department of the Abidjan Heart Institute Abidjan C&#244te d’Ivoire Hemodynamics Department of the Abidjan Heart Institute Abidjan C&#244te d’Ivoire Anesthesia and Intensive Care Department of the Abidjan Heart Institute Abidjan C&#244te d’Ivoire

Introduction: Despite the advances of interventional catheterization, surgery remains the treatment of choice for some coronary lesions. Objective: To report the indications and results of surgical revascularization of the myocardium at the Abidjan Heart Institute. Patient and Methods: This is a retrospective study of patients with coronary insufficiency who underwent surgical myocardial revascularization between March 2014 and May 2020 in the Cardiovascular Surgery Department of the Abidjan Heart Institute. There were 17 patients, 11 of whom were men (64.7%) and 6 women (35.3%), The mean age of the patients was 57.5 years ± 8.8. All patients were symptomatic with disabling angina in class III of the Canadian Cardiac Society (CCS). This sym- ptomatology had been evolving on average for 5 years and 6 patients had a history of acute coronary syndrome, 2 of whom had undergone prior angioplasty. Coronary angiography revealed mono-truncated (17.6%), bi-truncated (23.5%) and tri-truncated (58.8%) lesions. Results: The patients were operated under cardiopulmonary bypass (CPB) 15 cases (88.2%) and off pump in 2 cases (11.8%). They underwent a single bypass in 23.5% of cases, a double bypass in 47.1% of cases and a triple bypass in 29.4% of cases. We observed 3 cases of complications (17.6%), namely transient acute renal failure, mediastinitis and postoperative bleeding. The operative and hospital mortality was nil. After a mean follow-up of 3 ± 1.8 years, all patients were

关键词： Myocardial Revascularization Coronary Surgery Bypass