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Contribution of Satellite Observations in the Optical and Microphysical Characterization of Aerosols in Burkina Faso, West Africa

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Atmospheric and Climate Sciences 2024年第1期14卷 154-171页

作者： Nébon Bado serge Dimitri Bazyomo Germain Wende Pouiré Ouedraogo bruno Korgo Mamadou Simina Dramé Florent P. Kieno Sié Kam Laboratoire d’Energies Thermiques Renouvelables (L.E.T.RE) Université Joseph KI ZERBO Ouaga Burkina Faso Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon-Fongang Université Cheikh Anta DIOP Dakar-Fann Sénégal Institute of Mathematics and Physical Sciences University of Abomey-Calavi Porto-Novo Benin

In this work, we proceed to an optical and microphysical analysis of the observations reversed by the MODIS, SeaWiFS, MISR and OMI sensors with the aim of proposing the best-adapted airborne sensor for better monitoring of aerosols in Burkina Faso. To this end, a comparison of AOD between satellite observations and in situ measurements at the Ouagadougou site reveals an underestimation of AERONET AOD except for OMI which overestimates them. Also, an inter-comparison done based on the linear regression line representation shows the correlation between the aerosol models incorporated in the airborne sensor inversion algorithms and the aerosol population probed. This can be seen through the correlation coefficients R which are 0.84, 0.64, 0.55 and 0.054 for MODIS, SeaWiFS, MISR and OMI respectively. Furthermore, an optical analysis of aerosols in Burkina Faso by the MODIS sensor from 2001 to 2016 indicates a large spatial and temporal variability of particles strongly dominated by desert dust. This is corroborated by the annual and seasonal cycles of the AOD at 550 nm and the Angström coefficient measured in the spectral range between 412 nm and 470 nm. A zoom on a few sites chosen according to the three climatic zones confirms the majority presence of mineral aerosols in Burkina Faso, whose maxima are observed in spring and summer.

关键词： AERONET Airborne Sensors Aerosol Optical and Microphysical Properties

Climatological Analysis of Aerosols Optical Properties by Airborne Sensors and in Situ Measurements in West Africa: Case of the Sahelian Zone

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Open Journal of Air Pollution 2019年第4期8卷 118-135页

作者： Nébon Bado Adama Ouédraogo Hassime Guengané Thierry Sikoudouin Maurice Ky serge Dimitri Bazyomo bruno Korgo Mamadou Simina Dramé Saidou Moustapha Sall Florent P. Kieno Dieudonné Joseph Bathiebo Laboratoire d’Energies Thermiques Renouvelables (L.E.T.RE) Université Joseph Ki Zerbo Ouaga Burkina Faso Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang Université Cheikh Anta Diop Dakar-Fann Sénégal Centre Universitaire Polytechnique de Kaya (CUP-K) Kaya Burkina Faso Institute of Mathematics and Physical Sciences University of Abomey-Calavi Porto-Novo Benin

This paper deals with the climatology of aerosols in West Africa based on satellite and in situ measurements between 2001 and 2016 and covers four sites in the Sahelian zone. There are indeed Banizoumbou (13.541°N, 02.665°E), Cinzana (13.278°N, 05.934°W), Dakar (14.394°N, 16.959°W) and Ouagadougou (12.20°N, 1.40°W) located respectively in Niger, Mali, Senegal and Burkina Faso. Thus, an intercomparison between the satellite observations and the in situ measurements shows a good correlation between MODIS and AERONET with a correlation coefficient R = 0.86 at Cinzana, R = 0.85 at Banizounbou, R = 0.84 at Ouagadougou and a low correlation coefficient R = 0.66 calculated on the Dakar site. Like MODIS, SeaWiFS shows a very good correspondence with measurements of the ground photometer especially for Banizoumbou (R = 0.89), Cinzana (R = 0.88) and Dakar (R = 0.75) followed by a low correlation coefficient calculated on the Ouagadougou site (R = 0.64). The performance of these airborne sensors is also corroborated by the calculation of root mean square error (RMSE) and the mean absolute error (MAE). Following this validation, a climatological analysis based on aerosol optical depth (AOD) shows the seasonality of aerosols in West Africa strongly influenced by the climate dynamics illustrated by the MERRA model reanalysis. This seasonal spatial distribution of aerosols justifies the temporal variability of the particles observed at the different sites in the Sahel. In addition, a combined analysis of AOD and Angstrom coefficient indicates the aerosol period in the Sahel in spring (March-April-May) and summer (June-July-August). However, these aerosols are strongly dominated by desert dust whose main sources are located north in the Sahara and Sahel.

关键词： West-Africa Aerosols Airborne Sensors Aeronet MERRA Model

Epidemiology, Clinical and Paraclinical Presentations of Pulmonary Embolism: A Cross-Sectional Study in a Sub-Saharan Africa Setting

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Open Journal of Respiratory Diseases 2019年第3期9卷 89-99页

作者： Bertrand Hugo Mbatchou Ngahane Félicité Kamdem Silvain Raoul Simeni Njonnou Nina Chebou Anastase Dzudie serge Arnold Ebongue bruno Tengang Fernando Kemta Lekpa Yacouba Mapoure Njankouo Sidick Mouliom Henri Roger Ngote Henry Luma Namme Douala General Hospital Douala Cameroon Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Faculty of Medicine and Biomedical Sciences University of Yaounde 1 Yaounde Cameroon Military Hospital Douala Cameroon Centre des Maladies Respiratoires Douala Cameroon

Background: Venous thromboembolic (VTE) disease burden is increasing worldwide, representing a major cause of cardiovascular death and public health problem. Pulmonary embolism (PE) is the most serious clinical presentation of VTE. Epidemiological and clinical data on PE are still lacking in Africa, particularly in Cameroon. This study aimed at determining the clinical features as well as imaging presentation and outcome of pulmonary embolism. Methods: A cross-sectional study was carried out in three hospitals in Douala. We retrospectively reviewed patient records admitted for PE from January 2009 to May 2017. We collected data on epidemiology, clinical presentation, venous Doppler/pulmonary computed tomographic angiography (CTA), and outcome. Results: We included 103 patients (56 males) with PE. Their median age was 52 years. The main risk factors were obesity (49.5%), hypertension (35.0%), long trip (24.3%) and cancer (18.4%). The most frequent clinical presentations were dyspnoea (83.4%), chest pain (78.6%), and cough (40.8%). Additionally, pleural effusion (32.8%), atelectasis (25.7%) and pulmonary hyperlucency (20.0%) were the most frequent findings on chest X-ray. The main abnormalities found in electrocardiogram were sinus tachycardia (63.4%), S1Q3T3 aspect (37.6%) and right axial deviation (28.7%). Moreover, right cavities dilatation (26.0%), pulmonary artery hypertension (35.0%) and pulmonary artery dilatation (21.0%) were the main echocardiographic findings. Low-molecular-weight heparin (LMWH) was the initial anticoagulant in all cases. There were 19 (18.4%) in-hospital deaths, and the mean hospital stay was 8.5 ± 5 days. Conclusion: PE is not rare in our setting. Obesity, long trip and cancer are the main risk factors, while dyspnoea, chest pain and respiratory distress are the main clinical presentation for PE. LMWH remains the therapeutic agent of choice. Lastly, in-hospital mortality is very high.

关键词： Epidemiology Africa Venous Thromboembolism Symptoms

EGFR Expression Is Unreliable to Decide for Cetuximab Treatment in Patients with Metastatic Colorectal Cancer: Results from “ERBITUX-OUEST”

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Open Journal of Internal Medicine 2016年第2期6卷 56-67页

作者： Jean-Philippe Metges Erick Gamelin Alain Volant Olivier Capitain Jean-François Ramée Jean-Luc Raoul Jean-Yves Douillard Pierre-Luc Etienne Isabelle Cumin Olivier Dupuis Roger Faroux Marie-Aude Coulon Philippe Deguiral Karine Bideau Nacr Eddine Achour Alain Gourlaouen Corinne Alleaume Annie Wdowik Laurent Miglianico Yann Touchefeu Vincent Klein Alain Penchet Ludovic Rosenfeld Daniel Martin Claire Stampfli Jean-Jacques Auger Alain Bargain Murielle Broyer-Petit Jérome Chettrit Louis-Rémi De Ybarlucea serge Eloit Pierre Marie Girardot Nathalie Heresbach Christian Laboisse Eric Lavoine Gilles Lemasson Claire Magois Sophie Michalak Norbert Padilla Joseph Politis Frédéric Staroz bruno Turlin Arnaud Uguen Viorel Vasiliu Véronique Verriele Fanny Marhuenda Delphine Déniel Lagadec Christian Riché Françoise Grudé Observatoire dédié au Cancer des régions Bretagne et Pays de la Loire France Centre Hospitalier Régional Universitaire (CHRU) Brest France Institut de Cancérologie de l’Ouest (ICO) Paul Papin Angers France Centre Catherine de Sienne Nantes France CRLCC Eugène Marquis Rennes France ICO René Gauducheau Nantes France Centre CARIO-HCPA Plérin France Centre Hospitalier Bretagne Sud (CHBS) Lorient France Clinique Victor Hugo Le Mans France Centre Hospitalier Départemental (CHD) La Roche-sur-Yon France CH Le Mans France Clinique Mutualiste de l’Estuaire Saint-Nazaire France CHIC Quimper France Clinique Pasteur Lanroze Brest France CH MORLAIX France CH Saint-Brieuc France CHBA Vannes France CHP Saint-Grégoire France CHU Nantes France Hopital Privé Océane Vannes France Clinique Saint-Michel et Sainte-Anne Quimper France Pole Santé Sarthe et Loire La Flèche France Polyclinique du Maine Laval France Polyclinique Sud Quimper France CH Laval France Polyclinique Cesson Sévigné France Laboratoire d’anatomie et de cytologie pathologiques Cholet France Cabinet d’anatomie et de cytologie pathologiques Saint-Malo France Laboratoire d’anatomie et de cytologie pathologiques Lorient France Institut d’histopathologie Nantes France Laboratoire de Pathologie Médicale Laval France ARMOR Pathologie Plérin France Laboratoire d’anatomie et de cytologie pathologiques Rennes France Laboratoire d’anatomie et de cytologie pathologiques Angers France Laboratoire Analyses Biologie Glasgow Brest France CHU Angers France Centre d’anatomie et de cytologie pathologiques Le Mans France Cabinet d’anatomie et de cytologie pathologiques Vannes France Laboratoire d’anatomie et de cytologie pathologiques Quimper France CHU Rennes France

Purpose: Although controversial, assessment of epidermal growth factor receptor (EGFR) expression is required for the approved indications of Cetuximab in metastatic colorectal cancer (mCRC). With the objective of improving patient selection, “ERBITUX-OUEST” study aimed at analyzing EGFR status in a large cohort of mCRC patients who received cetuximab without preliminary EGFR screening, and assessing the correlation between EGFR status and response to treatment retrospectively. Patients and methods: 332 patients treated with Irinotecan Cetuximab based regimen after progression on irinotecan or oxaliplatin therapy were included. EGFR status was assessed using three available immunohistochemistry (IHC) tests and in situ hybridization in case of negativity. Clinical outcomes of EGFR-positive and EGFR-non-detected (or considered as negative with at least one test) patients were compared. Results: Of the 332 samples centrally screened, 194 were classified as full-positive (i.e., EGFR-positive for all three tests), 86 as full-negative, and 52 as discordant. One third of the 131 negative samples with FDA approved test should be reclassified as positive with at least one of the two others tests. Regarding results from FDA approved test only, neither objective response rate (ORR), progression-free survival (PFS) nor overall survival (OS) differed significantly between EGFR-negative and EGFR-positive patients (P = 0.788, 0.326 and 0.888, respectively). Similarly, comparison of full-negative to other groups did not show any significant difference in terms of ORR (P = 0.507), PFS (P = 0.222) or OS (P = 0.686). Conclusion: These data strongly argue against mCRC patients selection for Cetuximab treatment based on EGFR expression as measured by currently available IHC technics.

关键词： Metastatic Colorectal Cancer Cetuximab EGFR Expression