Nutritional and Clinical Profiles of Elderly People with Diabetes and Hypertension at Conakry University Hospitals

Introduction: In Guinea, there is few data on dietary practices socio-economic and clinical characteristics of elderly diabetics and hypertensives. Methods: This was a descriptive cross-sectional study of people aged 60 years and over, seen in consultation or hospitalised in Conakry University hospitals during the period from 5 September to 15 December 2023 inclusively. Results: Among the 320 subjects included in the study, there were more men (50.6%). The average age was 67 ± 7.69 years;53.43% had hypertension and 46.57% had diabetes. Sex was significantly associated with diabetes (p = 0.035). Women in the study were more affected by diabetes (55.7%), 64.4% of diabetic subjects were married and more than 64% of them had dependent children. 26.2% of diabetics were not employed;85.9% had an income;34.9% had an income of less than one million Guinean francs per month and 74.5% of them had 3 meals a day. Physical activity, 24-hour recall for lunch (p Conclusion: Effective management of diabetes and hypertension in the elderly should necessarily involve nutrition education in hospitals.

HPV/HBV or HPV/HCV Co-Infections in Women Treated for Chronic Hepatitis at Hôpital Saint Camille in Ouagadougou, Burkina Faso

Introduction: Cervical cancer is a public health concern and is mainly caused by Human papillomaviruses (HPV). In many parts of the world, studies are being carried out to understand the different genotypes to better tackle this issue. We conducted a study to determine the prevalence of HPV genotypes in women with chronic hepatitis B or C infection, co-infected or not with HIV, treated at the Hôpital Saint Camille in Ouagadougou (Burkina Faso). Methods: This study was conducted from April to July 2023, including 100 women in gastroenterology at Hôpital Saint Camille. A questionnaire on their socio-demographic and life style was administrated;and endocervical samples were collected using sterile swabs and then sent to Centre of Biomolecular Research Pietro Annigoni (CERBA). HPV molecular detection and genotyping were performed by PCR and hybridization using the HPV Direct Flow Chips kit. Data were analysis using chi square test or Fischer’s exact test with a significance threshold for p Results: The prevalence of HPV infection was 28% (28/100) on the sample of women tested. The most frequent genotypes were HPV 52 (8.33%), followed by HPV 18 and 68 (6.25% each) for high-risk HPVs, and HPV 6, 44/55 and 62/81 (8.33% each) for low-risk HPVs. Conclusion: This study, the first of its kind in Burkina Faso on this group of the population, reveals that the most frequent genotypes found in this study are not included in the vaccine available in Burkina Faso (Gardasil®4).

Assessment of Liver Fibrosis in HBsAg-Negative and Anti HBc Positive Patients

Background: Surface antigen (HBsAg) is the mean marker of hepatitis B virus infection. During the course of the infection, some patients lose the HBsAg and only the presence of anti-HBc antibody indicates previous contact with the virus. Among these patients, some have detectable viral load (occult infection) but most without viral replication. There is no guideline regarding these patients. The aim of this study was to assess hepatic fibrosis in patients with only the hepatitis B virus contact marker “total anti-HBc”. Patients and methods: it was a descriptive and analytical cross-sectional study, conducted in three private hospitals from January to August 2022. Were included HBsAg-negative and HBc-positive patients, consulting in Gastroenterology departments. Noninvasive methods (APRI, FIB-4 and FIBROSCAN) were used to evaluate liver stiffness because of their easy accessibility and low-cost. The hepatic fibrosis was considered significant when the score determined by APRI, FIB-4 and FIBROSCAN® tests was respectively greater than 1.5;2.67 and 8 kPa corresponding to fibrosis level 2 (F2). Results: A total of 63 HBsAg-negative/total HBcAg-positive patients were included. The mean age was 49.9 ± 13.4 years. The male/female sex ratio was 1.78. Of the 63 patients, 19 had significant liver fibrosis (30.1%) among which 9 patients had HCC. The FIB-4 score outperformed the APRI score in assessing liver fibrosis, with a sensitivity of 84.2%, a specificity of 100% and a negative predictive value of 93.6%. In univariate analysis, there was a significant association between the occurrence of significant liver fibrosis and age over 40 years, dyslipidaemia, obesity, alcohol consumption, smoking, herbal medicine, negative anti-HBs immunological status and detectable viral load. Conclusion: Our study revealed a high prevalence of significant to severe hepatic fibrosis in anti-HBc positive patients. In most of the cases, the fibrosis was severe. Progression to HCC has also been possible. There is no consensus on the follow-up strategy for those patients. However, screening for hepatic fibrosis using noninvasive methods should be recommended for patients aged over 40 years, alcohol or herbal medicine users, patients with metabolic syndrome or occult hepatitis B. In HBsAg-negative/anti-HBc-positive patients, liver stiffness should be evaluated and if it is greater than F2, HCC screening should be started.

Mother-to-Child Transmission of Human Papillomavirus in Burkina Faso

Introduction: Human papillomavirus (HPV) infection is the most widespread sexually transmitted infection in the world. Today, there is growing evidence that HPV can be transmitted early in life, and one potential route is mother-to-child transmission. Data on this route of HPV transmission are scarce in Africa and particularly in Burkina Faso, where no data on the subject are yet available. The aim of our study was to estimate the rate of mother-to-child transmission of HPV infection and to identify circulating genotypes. Methodology: Cervico-uterine samples were collected from 100 full-term pregnant women and, buccal samples were obtained from their newborns at Hopital Saint Camille de Ouagadougou (HOSCO) by the specialist physician. HPV DNA amplification and genotyping were performed by PCR followed by hybridization using the HPV Direct Flow Chips kit, detecting 36 genotypes including 18 high-risk and 18 low-risk. Results: The prevalence of HPV in newborns was 8% (8/100). Six (6) HPV-positive neonates had HPV-positive mothers, while 2 HPV-positive neonates had HPV-negative mothers. The vertical transmission rate was 26.09% (6/23). Mother-newborn genotypes were concordant. However, the genotype profile of the newborns was more restricted than that of the mothers. Conclusion: HPV DNA was found in 8% of newborns in our study. The genotype profile of the mother-newborn pair was concordant. Asymptomatic HPV infection in a pregnant woman could constitute a risk factor for vertical transmission.

On a Compound Poisson Risk Model Perturbed by Brownian Motion with Variable Premium and Tail Dependence between Claims Amounts and Inter-Claim Time

This paper considers the compound Poisson risk model perturbed by Brownian motion with variable premium and dependence between claims amounts and inter-claim times via Spearman copula. It is assumed that the insurance company’s portfolio is governed by two classes of policyholders. On the one hand, the first class where the amount of claims is high, and on the other hand, the second class where the amount of claims is low, this difference in claim amounts has significant implications for the insurance company’s pricing and risk management strategies. When policyholders are in the first class, they pay an insurance premium of a constant amount c1 and when they are in the second class, the premium paid is a constant amount c2 such that c1 > c2. The nature of claims (low or high) is measured via random thresholds . The study in this work will focus on the determination of the integro-differential equations satisfied by Gerber-Shiu functions and their Laplace transforms in the risk model perturbed by Brownian motion with variable premium and dependence between claims amounts and inter-claim times via Spearman copula. .

Simulation and Performance Analysis of Six Types of Sun Tracker Approaches:A Comparative Analysis for Solar Concentrating Technology Application at Burkina Faso

Modelization equations of six approaches for tracking the sun are recalled and used to evaluate the constraints and performances to which they lead to.The geographical study case is taken for the specific latitude of 12 North that is a good matching with the location of the country of Burkina Faso.Three decisive periods were locally established in order to consider the different travels of the sun on sky during one year.This work presents some technical data which facilitates the choice of sun tracking approaches with concern of a concentrator limits such as its angle of acceptance,its motion control card interpolation model,or its minimum irradiation level for energy conversion effectiveness.

Seroprevalence of HBV and HCV among People Living with HIV in Burkina Faso and Diagnostic Performance of HIV/HCV/HBsAg Combined Rapid Test in Comparison with Architect Assays

Background: The diagnosis of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) remains a constraint for some populations in sub-Saharan Africa. This study aimed to determine the prevalence of HBV and HCV in people living with HIV and to evaluate the performance of a combined rapid test for the simultaneous detection of HIV, HBV, and HCV. Methods: This is a cross-sectional study that took place from February 2017 to November 2018 and included 139 HIV-infected individuals followed up at different medical centers in Ouagadougou, Burkina Faso. HBV and HCV serology tests were performed on-site using finger prick whole blood with HIV/HCV/HBsAg combined rapid test and then serum with two reference tests “Architect HBsAg Qualitative” and “Architect HIV Ag/Ab Combo”. Results: The mean age of the participants was 57 ± 8 years. Of the 139 participants, 10% (14/139) were HIV-1 positive, 71.9% (100/139) were HIV-2 positive, and 18.0% (25/139) were HIV-1/HIV-2 coinfected. The sensitivity and specificity of the HIV/HCV/HBsAg combined rapid test were 33.33% vs 99.11% and 20% vs 99.25% compared to Architect HBsAg Qualitative and Architect HIV Ag/Ab Combo, respectively. The Kappa and Youden Index values were 0.4262 and 0.3244 and 0.2707 and 0.1925, respectively, compared to each of the two reference tests. Conclusion: The results show that the HIV/HCV/HBsAg combined rapid test has poor diagnostic efficiency and should not be recommended for the diagnosis of these viruses.

Systematic Analysis of Factors Associated with Late Breast Cancer Screening in Women in Sub-Saharan Africa from 2014 to 2020

Research background: Breast cancer remains a major public health problem, with a high number of new cases and deaths each year. However, despite advances in research to improve this disease, there is a high rate of late detection, leading to diagnosis at an advanced stage and a reduced chance of survival. Objective: The aim of this study is to identify the factors associated with late detection of breast cancer in women in Sub-Saharan Africa from 2014 to 2020.Setting: This systematic review focuses on sub-Saharan Africa. Methods: We searched for articles in four databases (PubMed, Embase, Global-Health and CINAHL) between 2014 and 2020 and performed a narrative synthesis to organize and group the different factors associated with late breast cancer detection. Result: After reviewing 583 publications, 6 studies were selected, highlighting factors such as lack of awareness, knowledge gaps, difficulties in accessing health services and financial constraints associated with late breast cancer screening. The participants, who ranged in number from 20 to 1776, were mainly aged between 18 and 25, with a mean age of 25 years and 6 months. Conclusion: The analysis enabled us to identify various factors associated with late breast cancer screening. Collaboration between health professionals, community organizations and policy-makers is essential to foster an environment conducive to the prevention and early detection of breast cancer.

Genetic diversity and occult hepatitis B infection in Africa: A comprehensive review

BACKGROUND Occult hepatitis B infection(OBI)is a globally prevalent infection,with its frequency being influenced by the prevalence of hepatitis B virus(HBV)infection in a particular geographic region,including Africa.OBI can be transmitted th-rough blood transfusions and organ transplants and has been linked to the development of hepatocellular carcinoma(HCC).The associated HBV genotype influences the infection.AIM To highlight the genetic diversity and prevalence of OBI in Africa.METHODS This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and involved a comprehensive search on PubMed,Google Scholar,Science Direct,and African Journals Online for published studies on the prevalence and genetic diversity of OBI in Africa.RESULTS The synthesis included 83 articles,revealing that the prevalence of OBI varied between countries and population groups,with the highest prevalence being 90.9%in patients with hepatitis C virus infection and 38%in blood donors,indicating an increased risk of HBV transmission through blood transfusions.Cases of OBI reactivation have been reported following chemotherapy.Genotype D is the predominant,followed by genotypes A and E.CONCLUSION This review highlights the prevalence of OBI in Africa,which varies across countries and population groups.The study also demonstrates that genotype D is the most prevalent.

Numerical Assessment of the Thermal Efficiency of a Concentrated Photovoltaic/Thermal (CPV/T) Hybrid System Using Air as Heat Transfer Fluid

In this paper, we propose a thermal model of a hybrid photovoltaic/thermal concentration system. Starting from the thermal balance of the model, the equation is solved and simulated with a MATLAB code, considering air as the cooling fluid. This enabled us to evaluate some of the parameters influencing the electrical and thermal performance of this device. The results showed that the temperature, thermal efficiency and electrical efficiency delivered depend on the air mass flow rate. The electrical and thermal efficiencies for different values of air mass flow are encouraging, and demonstrate the benefits of cooling photovoltaic cells. The results show that thermal efficiency decreases air flow rate greater than 0.7 kg/s, whatever the value of the light concentration used. The thermal efficiency of the solar cell increases as the light concentration increases, whatever the air flow rate used. For a concentration equal to 30 sun, the thermal efficiency is 0.16 with an air flow rate equal to 0.005 kg/s;the thermal efficiency increases to 0.19 with an air flow rate equal to 0.1 kg/s at the same concentration. An interesting and useful finding was that the proposed numerical model allows the determination of the electrical as well as thermal efficiency of the hybrid CPV/T with air flow as cooling fluid.

Cytotoxic Properties on Cervical and Liver Cancer Cells of Two Plant Recipes from Burkina Faso

Cancer is one of the deadliest diseases in developing countries. In recent years, natural plant-based compounds have been used in the search for drugs to combat numerous diseases, including cancer. In this study, we evaluate the cytotoxic properties of paanfo tiben 1 and paanfo tiben 2, two traditional herbal formulations from Burkina Faso used in the treatment of cancer in Burkina Faso. To this end, the recipes were infused and freeze-dried. The dry extracts obtained were used to determine total phenolics and flavonoids content, assess antioxidant activity using the DPPH, ABTS and FRAP methods, evaluate anti-inflammatory properties by inhibiting 15-LOX, COX 1 and 2, and assess cytotoxic activity on HeLa cervical cancer and HePG2 liver cancer cell lines using the MTT test. The paanfo tiben 1 recipe showed the highest levels of total phenolics and flavonoids, as well as the best antioxidant activities, with IC50 values of 21.020 ± 0.6 µg/ml and 22.94 ± 0.57 µg/ml for DPPH and ABTS, and 165.15 mM EAA/mg dry extract for FRAP. It also exhibited the best cytotoxic activity with IC50 values of 112.02 ± 0.025 µg/ml on HeLa cells and 80.67 ± 6.08 µg/ml on HepG2 cells. On the other hand, paanfo tiben 2 exhibited the best anti-inflammatory activities through inhibition of 15-LOX and COX 1, with inhibition percentages at 100 µg/ml of 32.523% and 24.717 % respectively. These results could justify the traditional use of these two recipes by traditional health practitioners in the treatment of cancer sufferers in Burkina Faso.

Manufacture of Industrial Refractory Crucibles Based on Clays from Burkina Faso

In Burkina Faso, one of the three largest gold producers in West Africa, foundry activity is often paralyzed when basic equipment such as crucibles and cups are not available or should be imported. However, previous studies have shown the availability of kaolinite-rich clay resources that could be used for the local manufacture of silico-aluminous ceramic crucibles. This work allowed to manufacture industrial ceramic crucibles with local clays and then they were tested in foundry industry. The materials were manufactured from three (03) raw materials including two clays (SAB and ROU) and sand. The chemical and mineral analysis has shown that the raw materials are suitable for the formulation of refractory materials. The results of characterization of the materials formulated showed that the properties of use are appreciable. The porosity of the materials is relatively low (23 - 28 vol%) with a diametral compressive strength between 0.61 and 1.34 MPa. Crucibles sintered at 1250˚C with a stay of 2 hours have a mechanical strength capable of supporting the weight of the ores contained. These crucibles have a refractoriness under load (T0.5) above 1141˚C and resist chemical attacks. Tests were carried out in the industry at 1100˚C, and the results were satisfactory.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Measurement of Radon Concentration and Estimation of Cancer Risk in Twenty-Four Model Houses in the Town of Koudougou

The objective of our study is to evaluate the concentration of radon (86Rn) inside houses in the town of Koudougou in order to estimate its impact on the health of the population. Indeed, when uranium-rich minerals are found near the surface of the ground, radon concentrations can reach tens of becquerels per cubic meter in enclosed spaces. Given the nature of the geological base of Burkina Faso, this situation is quite probable and certain places that are sometimes poorly ventilated (house, school, office, etc.) can have radon levels high enough to constitute a health problem for occupants. Thus, twenty-four (24) sample houses were identified. In each house, the Corentium digital detector was between 0.8 m and 2 m for at least one week in a place where the occupants estimate that they spend more time of time and measure the concentration of radon in the long term and short term. The recorded data allowed us to determine the Absorbed Dose and the Annual Effective Dose of radon gas for each house in order to estimate the Risk of Cancer and the probable Number of Cases of Lung Cancer per million inhabitants. Thus, the results indicate that the long-term radon concentration varies between 6 Bq/m3 and 285 Bq/m3 respectively in houses 11 and 4 compared to 1 Bq/m3 to 208 Bq/m3 in the short term in the same houses. Also, in the long term, in control houses 1, 3 and 4, the radon level is above the recommended threshold interval. For the short term, these are houses 1, 3, 4 and 17 respectively with 110 Bq/m3, 142 Bq/m3, 208 Bq/m3 and 105 Bq/m3. As for the long-term and short-term effective doses, only houses 1, 3, 4, 17 and 24 have values between 3 - 10 Sv/year. The estimation of the relative risk of lung cancer gives values relatively close to unity and between 1.006 and 1.142 with an average of 1.035 and that of the Number of Lung Cancer Cases per million inhabitants gives values between 8 and 166 with an average of 42. Thus, we can conclude that with the exception of houses 1, 3, 4 and 17, the radon concentrations are relatively low in the twenty-four control houses in the city of Koudougou. The lifestyle of the populations can well explain this situation when we know that people are in the habit of always leaving doors and windows open, especially when they are not sleeping. We can therefore say that the risk of population exposure to radon gas is relatively low in the town of Koudougou.

Phytochemical Composition and Insecticidal Property of Native Plants against the Cowpea Weevil Callosobruchus maculatus Fab. (Coleoptera: Bruchidae) for Natural Preservation of Cowpea Seeds

About 80% of cowpea seeds are lost along with 30% of their weight after six months of unprotected storage due to attacks by Callosobruchus maculatus. This study aimed at evaluating the effect of applying bioinsecticides on the biological parameters of C. maculatus to reduce its damage to cowpea stocks. Four treatments including an untreated control and three doses of powdery extracts of C. nigricans, Z. zanthoxyloides and H. suaveolens, were compared in a Fischer block with four completely randomized repetitions. One hundred undamaged cowpea seeds were mixed with doses of each extract in Petri dishes and then fed as food substrates to ten pairs of C. maculatus for eight days. The extracts of H. suaveolens, C. nigricans and Z. zanthoxyloides all contain active ingredients including polyphenols, flavonoids, anthocyanins and alkaloids, etc. The extract of Z. zanthoxyloides was found to be more active on adults (100.00% mortality) followed by C. nigricans (98.75% mortality) and H. suaveolens (97.50% mortality) at 80 mg/g. Fecundity per female decreased significantly in the treated batches of 13.82 eggs for H. suaveolens at 10.12 eggs for C. nigricans at a dose of 80 mg/g. Germination rate of seeds was statistically raised to 100% at 60 and 80 mg/g by C. nigricans powder and lowered to 83.00% at 20 mg/g by Z. zanthoxyloides extracts. The application of Z. zanthoxyloides extract would be a less expensive alternative for the sustainable management of C. maculatus in cowpea stocks.

Influence of Heavy Fuel Oil on the Thermo-Physical and Erodibility Properties of Earthen Materials

This study focuses on the use of heavy fuel oil in construction material in Burkina Faso. Its mixture with silty or clayey soil is used as a coating to reinforce the walls of raw earth constructions which are very sensitive to water. The interest of this study is to determine erodibility, water content, while highlighting the influence of the porosity accessible by water on thermal diffusion in construction material containing heavy fuel oil. The heavy fuel oil was mixed with a silty-clayey soil, in different proportions, and water to make bricks samples on which tests were carried out. At the end of the experimental tests, it appears that the water content increases gradually, but not significantly with the addition of heavy fuel oil, which causes a slight increase in the speed of heat propagation through the material with reduced porosity, particularly those containing higher quantities of heavy fuel oil. Conversely, we note a good performance of heavy fuel oil in terms of water resistance properties such as porosity accessible by water and erodibility. This allows us to conclude that the mixture of heavy fuel oil and silty-clayey soil used as a coating material could greatly reduce water infiltration into the walls of housing constructions with raw earthen materials.

Temperature Effect on Light Concentration Silicon Solar Cell’s Operating Point and Conversion Efficiency

It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (CPV). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (MPP) moves to the open circuit when the cell temperature increases.

Usability of a Natural Tuff as Admixture in Clinker and Its Influence on the Physico-Chemical and Mechanical Properties of Mortar

The mechanical and physical properties of TUFF from Korsimoro (Burkina Faso) were investigated for use as admixtures in clinker to make pozzolanic cement. Six different cement mortar specimens were prepared by replacing clinker with TUFF in ratios of 0%, 5%, 8%, 10%, 13% and 15% by mass. The flexural and compressive strengths of the specimens were determined at the ages of 2, 7, 28 and 60 days. The effects of the TUFF replacement ratio on workability, setting time and volume expansion were also examined. Based on the results, it was concluded that Korsimoro TUFF has pozzolanic activity and is suitable for use as an alternative adherent material in the cement industry.

Trace Metal Elements (Pb, Cd and As), 15N Nitrogen and Phosphorus Isotopes Accumulation in Three Varieties of Tomato from Conventional and Agro-Ecological Farming Systems in Burkina Faso

Tomato is a market gardening product that plays an important nutritional and economic role in Burkina Faso. However, the bad use of pesticides for its production could have negative impacts consumers’ health. The objective of the present study was to assess the concentration of trace metal elements (Pb, Cd and As), 15N isotopes (NO2-, NO3-, NH4+) and phosphorus (PO42-) in tomatoes according to cultivation practices. Thus, three tomato varieties (Mongal F1, F1 Cobra 26 and Roma F1) were grown using organic and conventional production methods on 2 sites at Nongr Massom, (commune of Kadiogo province). The trace metal elements were analyzed using atomic absorption spectrophotometry, the isotopes 15N (NO2-, NO3-, NH4+) and phosphorus (PO43-) using standardized methods. Tomatoes from conventional agriculture had higher levels of trace metal elements (0.163 - 0.298 mg/Kg, 0.082 - 0.146 mg/Kg and 0.018 - 0.032 mg/Kg respectively for Pb, Cd and As) than those from organic agriculture samples. Concentration of trace metal is lower for organic production with a reduction of 19.02%, 19.69% and 20.77% for Pb, Cd and As respectively compared to conventional production. High levels were recorded for the Roma F1 variety. The concentrations of trace metal elements in organic production are lower than the codex standards (2010) while those in conventional production are higher. These results could be due to the use of chemical inputs that could have a negative impact on the nutritional quality of these tomatoes. The concentration of trace metal elements in tomato fruits is strongly correlated by production method and less by the variety (genetic).

Study and Design of a DC/AC Energy Converter for PV System Connected to the Grid Using Harmonic Selected Eliminated (HSE) Approach

Nowadays, distributing network-connected photovoltaic (PV) systems are expanded by merging a PV system and a Direct Current (DC)/Alternating Current (AC) energy converter. DC/AC conversion of PV energy is in great demand for AC applications. The supply of electrical machines and transfer energy to the distribution network is a typical case. In this work, we study and design a DC/AC energy converter using harmonic selective eliminated (HSE) method. To this end, we have combined two power stages connected in derivation. Each power stage is constituted of transistors and transformers. The connection by switching of the two rectangular waves, delivered by each of the stages, makes it possible to create a quasi-sinusoidal output voltage of the inverter. Mathematical equations based on the current-voltage characteristics of the inverter have been developed. The simulation model was validated using experimental data from a 25.2 kWp grid-coupled (PV) system, connected to Gridfit type inverters. The data were exported and implemented in programming software. A good agreement was observed and this shows all the robustness and the technical performances of the energy converter device. It emerges from this analysis that the inverter output voltage and the phase angle thus simulated are very important to control in order to orientate the transfer of the power flow from the continuous cell to cell to the alternating part. Simulated and field-testing results also show that increases in the value of the modulation factor (m) for low power output are highly significant. This study is an important tool for DC/AC inverter designers during initial planning stages. A short presentation of the design model of the inverter has been proposed in this article.