Background: Helicobacter pylori (Hp) infection is the most widespread bacterial infection in the world. The infection is generally acquired in childhood, but can persist into adulthood. Eradication therapy has undergo...Background: Helicobacter pylori (Hp) infection is the most widespread bacterial infection in the world. The infection is generally acquired in childhood, but can persist into adulthood. Eradication therapy has undergone several modifications. The aim of this study was to evaluate the different therapeutic strategies used in the eradication of Helicobacter pylori infection in the Centre Hospitalier Universitaire La Reference Nationale of N’Djaména. Patients and Methods: This was a prospective, descriptive analytical study spread over one year, from September 2021 to September 2022. Patients at least 15 years of age presenting with dyspeptic symptoms, seen consecutively in a hepato-gastroenterology consultation and with a positive stool test for H. pylori infection, were included in the study. Equally, 1/3 of patients were treated with dual or triple therapy. The remaining third received quadritherapy. Results: A total of 268 patients were included in the study (mean age 38.40 ± 14.66 with extremes of 16 and 80 years). Males predominated in 58% of cases. Overall therapeutic efficacy was 88.9%. According to different therapeutic strategies, efficacy was 90.75% for dual therapy with PPI (Rabeprazole) and Amoxicillin. On the other hand, efficacy was 87% and 88.88% for PPI-based triple therapy and dual antibiotic therapy, and for PPI-based quadruple therapy and triple antibiotic therapy. Conclusion: H. pylori infection is a common disease in Chad. Dual therapy with rabeprazole combined with a high dose of amoxicillin over a period of at least two weeks showed similar if not better efficacy than triple or quadruple therapy.展开更多
Introduction: The treatment of viral hepatitis C (HCV), a major public health problem, has evolved considerably since the introduction of direct-acting anti-virals (DAAs). The aim of this study was to evaluate the str...Introduction: The treatment of viral hepatitis C (HCV), a major public health problem, has evolved considerably since the introduction of direct-acting anti-virals (DAAs). The aim of this study was to evaluate the strategy for initiating treatment with Sofosbuvir/Daclatasvir, and also to assess its efficacy. Patients and Methods: Included were patients aged at least 15 years, with detectable hepatitis C viremia and treated with a pan-genotypic Sofosbuvir/Daclatasvir regimen at the Centre “Hospitalier Universitaire la Référence Nationale de N’Djamena” between October 2019 and October 2023. The APRI score was used to assess fibrosis. Cure was defined by an undetectable viral load 12 weeks after the end of treatment. Results: A total of 835 patients were included (sex ratio 1.55, mean age 50.5 ± 13.73, extremes 20 and 84 years). The 60 - 69 age group was the most represented. The mean APRI score was 0.42 ± 0.29, with extremes of 0.019 and 1.84. The mean viral load was 2,316,193.086 IU/mL. All subjects had good renal function. Cytolysis was absent in 70% of cases. Without genotyping, a pan-genotypic regimen was used in all patients: Sofosbuvir (400 mg)/Daclatasvir (60 mg). The cure rate was 99.4%, with good tolerability. However, four cases of failure were recorded out of the 668 patients who underwent follow-up HCV-PCR testing after 12 weeks of treatment. Conclusion: The Sofosbuvir/Daclatasvir regimen is highly effective, with an excellent safety profile. However, the still high cost of these molecules limits their accessibility to a large proportion of patients.展开更多
The study carried out concerns the valorization of agricultural waste for the development of biosourced materials that can be used as insulation in homes. This article is devoted to the influence of gum arabic on the ...The study carried out concerns the valorization of agricultural waste for the development of biosourced materials that can be used as insulation in homes. This article is devoted to the influence of gum arabic on the mechanical and thermal properties of clay soils in the town of Abéché. The mechanical tests were carried out using the CBR press equipped with two devices (bending device and compression device). Thermal property such as thermal conductivity was determined by the hot wire method and thermal resistance was derived by calculation. Thus, the tests were carried out on test pieces made from a mixture of clay and gum arabic in solution. The experimental program includes seven formulations (0%, 2%, 4%, 6%, 8%, 10% and 12%). The results obtained showed that the best flexural and compressive strengths are obtained by using gum arabic with a rate of 8% and a maximum stress of 4.3 MPa. In addition, the thermal results also showed that the thermal conductivity decreases when the percentage of gum arabic increases, which makes it possible to increase the thermal resistance, thus confirming the capacity of gum arabic to provide thermal insulation.展开更多
With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brick...With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brickwork in Abeche from a depth of 1 m, then using a clay brick-making press, 4 × 5 × 8 cm3 clay test tubes were made with 2%, 4%, 6% and 8% cow dung, and a 100% clay sample was used as a control. These samples underwent thermophysical characterization using the hot-wire method with a hot-plane option, yielding results that could improve thermophysical performance. The thermal conductivity of the test sample is in the order of 0.715 to 0.420 W/m. K, at 8% for cow dung, so the addition of cow dung as a percentage in the clay matrix enabled us to obtain various satisfactory thermal parameters.展开更多
Background: Although hepatocellular carcinoma was historically considered an important scourge in Middle Africa, there is no publication describing this disease in Chad. Methods: We conducted a retrospective analysis ...Background: Although hepatocellular carcinoma was historically considered an important scourge in Middle Africa, there is no publication describing this disease in Chad. Methods: We conducted a retrospective analysis of 219 patients with hepatocellular carcinoma (HCC) attending care at the University Reference Hospital of Ndjamena between 2007 and 2016. Results: This series of HCC was characterized by a male predominance (M:F = 2.4) with a mean tumor onset at the end of the fifth decade of life (49.9 ± 14.7 years). Tumors appear on a cirrhotic liver in 70% of cases and were already multifocal at diagnosis in two thirds of the patients. Alpha-fetoprotein was above the physiological threshold (10 ng/mL) in 73.4% of cases measured and above the so-called diagnostic level (400 ng/mL) in 53.4% of patients. The principal risk factor was chronic infection with hepatitis B virus, detected in 52.6% of cases. Patients seropositive for hepatitis C virus were infrequent (8.6%) and heavy alcohol intake was even less prevalent (5.9%). Remarkably, a very large subset of patients did not present any infectious or lifestyle risk factor (43.4%). Mean AFP values or fibrosis assessment scores are usually lower in these patients than in HBV-infected ones. Conclusions: The etiological spectrum of HCC is far from being fully established in Chad. Further epidemiological research is warranted to identify risk factors involved in a large proportion of cases. Exposure to aflatoxin B1 and dysmetabolic conditions affecting the liver have to be investigated as priority.展开更多
Background: In comparison to other forms of chronic liver diseases, cirrhosis is generally poorly studied in sub Saharan Africa. In Chad, more particularly, no data are available despite the burden of liver diseases c...Background: In comparison to other forms of chronic liver diseases, cirrhosis is generally poorly studied in sub Saharan Africa. In Chad, more particularly, no data are available despite the burden of liver diseases considered as the first cause of hospitalizations in the country. Methods: We conducted a retrospective analysis of 268 patients with liver cirrhosis attending care at the University Reference Hospital between 2007 and 2016. Results: This series of liver cirrhoses was characterized by a weak mal predominance (M:F = 1.7). The age of onset occurs significantly earlier in women than in men (40.6 ± 12.0 vs. 44.4 ± 13.4, p = 0.0171). The principal risk factor was persistent infection with hepatitis B virus (49% of cases) followed distantly by infection with hepatitis C virus (13%) and excessive alcohol consumption (10%). Men were more frequently carrying HBV surface antigen than women (65.6% vs 35.9% p = 0.0019). HBV-associated liver cirrhosis was overall more severe than diseases from other causes. A large proportion of cirrhosis (30%), observed primarily in women (48.1% vs 24.1%, p = 0.0036), was considered are cryptogenic. Conclusions: The etiological spectrum of liver cirrhosis remains to be properly defined in Chad. This lack of knowledge prevents the implementation of an efficient policy of prevention. A significant effort should be secured to characterize hitherto neglected infectious, lifestyle or genetic risk factors responsible of this form of terminal disease and improve subsequently liver health of local populations.展开更多
The evolution of global mobile data over the past decades in broadcasting, Internet of Things (IoT), education, healthcare, commerce, and energy has put strong pressure on 3G/4G mobile networks to improve their servic...The evolution of global mobile data over the past decades in broadcasting, Internet of Things (IoT), education, healthcare, commerce, and energy has put strong pressure on 3G/4G mobile networks to improve their service offerings. These generations of mobile networks were initially invented to meet the requirements of the above-mentioned applications. However, as the requirements in these applications continue to increase, new mobile technologies such as 5G (fifth generation), 5G and beyond (B5G, beyond fifth generation), and 6G (sixth generation) are still progressing and being experimented. These networks are very heterogeneous generations of mobile networks that will have to offer very high throughput per user, good energy efficiency, better traffic capacity per area, improved spectral efficiency, very low latency, and high mobility. To meet these requirements, the radio interface of future mobile networks will have to be flexible and rationalized the available frequency resources. Therefore, new modulation methods, access techniques and waveforms capable of supporting these technological changes are proposed. This review presents brief descriptions of the types of 5G, B5G, and 6G waveforms. The 5G consists of OFDM including its transmission techniques: generalized frequency division multiplexing (GFDM), filter bank based multi-carrier (FBMC), universal filtered multi-carrier (UFMC), and index modulation (IM). Meanwhile, the 6G covers orthogonal time frequency space (OTFS), orthogonal chirp division multiplexing (OCDM) and orthogonal time sequence multiplexing (OTSM). The networks’ potentialities, advantages, disadvantages, and future directions are outlined.展开更多
The characteristics of viral hepatitis B and D co-infection are poorly documented in Chad. The aim of our study was to determine the prevalence of HBV/HDV co-infection and the characteristics of this co-infection. Mat...The characteristics of viral hepatitis B and D co-infection are poorly documented in Chad. The aim of our study was to determine the prevalence of HBV/HDV co-infection and the characteristics of this co-infection. Materials and Methods: This was a retrospective study including all patients with chronic HBsAg carriers referred in our department from January 2014 to December 2018. Non-inclusion criteria were: absence of anti-HDV testing, presence of anti-viral hepatitis C or Human Immunodeficiency Virus antibodies or excessive alcohol consumption. The variables studied were age, sex, blood transaminase level, HBV DNA level, HDV RNA level, and liver fibrosis and activity score (Actitest Fibrotest). The prevalence of HDV and the characteristics of HDV/HBV co-infection were determined. Results: During the study period, 403 patients were seen in these two hospitals for chronic HBsAg carriage. Of these, 378 (75%) had performed the anti HDV assay. Anti-HDV antibodies were positive in 53 patients (14%). In multivariate analysis, HBV/HDV co-infected patients were less frequently HBeAg positive (5.4% vs. 28.1%;p = 0.0001), older (35 years vs. 32 years;p = 0.001), and more frequently had significant necrotic-inflammatory activity (3.9% vs. 3.2%;p = 0.031) compared with mono infected patients. Neither gender (76.9% male vs. 77.4% male;p = ns), nor viral load (median 530 IU/ml vs. 195 IU/ml;p = ns), nor significant liver fibrosis (35.1% vs. 47.1%;p = ns), nor transaminases (median 26 vs. 32 IU/ml) were different with mono infected patients. Conclusion: VHD is common in Chad. It is associated with increased hepatic necrotic-inflammatory activity.展开更多
In this paper, we aim to solve a two compartmental mathematical model of ordinary differential equations for cardiovascular-respiratory system using a new recent method: Perturbation Iteration method. The description ...In this paper, we aim to solve a two compartmental mathematical model of ordinary differential equations for cardiovascular-respiratory system using a new recent method: Perturbation Iteration method. The description of this method for different order derivatives in the Taylor Series expansion is discussed. This method provides the solution in the form of an infinite series for ordinary differential equation. The efficiency of the method used is investigated by a comparison of Euler method and Runge Kutta. Numerical simulations of all these three methods are implemented in Matlab. The validation has been carried out by taking the values of determinant parameters of cardiovascular-respiratory system for a 30 years old woman who is supposed to make practice of three regular physical activities: Walking, Jogging and Running fast. The results are in good agreement with experimental data.展开更多
文摘Background: Helicobacter pylori (Hp) infection is the most widespread bacterial infection in the world. The infection is generally acquired in childhood, but can persist into adulthood. Eradication therapy has undergone several modifications. The aim of this study was to evaluate the different therapeutic strategies used in the eradication of Helicobacter pylori infection in the Centre Hospitalier Universitaire La Reference Nationale of N’Djaména. Patients and Methods: This was a prospective, descriptive analytical study spread over one year, from September 2021 to September 2022. Patients at least 15 years of age presenting with dyspeptic symptoms, seen consecutively in a hepato-gastroenterology consultation and with a positive stool test for H. pylori infection, were included in the study. Equally, 1/3 of patients were treated with dual or triple therapy. The remaining third received quadritherapy. Results: A total of 268 patients were included in the study (mean age 38.40 ± 14.66 with extremes of 16 and 80 years). Males predominated in 58% of cases. Overall therapeutic efficacy was 88.9%. According to different therapeutic strategies, efficacy was 90.75% for dual therapy with PPI (Rabeprazole) and Amoxicillin. On the other hand, efficacy was 87% and 88.88% for PPI-based triple therapy and dual antibiotic therapy, and for PPI-based quadruple therapy and triple antibiotic therapy. Conclusion: H. pylori infection is a common disease in Chad. Dual therapy with rabeprazole combined with a high dose of amoxicillin over a period of at least two weeks showed similar if not better efficacy than triple or quadruple therapy.
文摘Introduction: The treatment of viral hepatitis C (HCV), a major public health problem, has evolved considerably since the introduction of direct-acting anti-virals (DAAs). The aim of this study was to evaluate the strategy for initiating treatment with Sofosbuvir/Daclatasvir, and also to assess its efficacy. Patients and Methods: Included were patients aged at least 15 years, with detectable hepatitis C viremia and treated with a pan-genotypic Sofosbuvir/Daclatasvir regimen at the Centre “Hospitalier Universitaire la Référence Nationale de N’Djamena” between October 2019 and October 2023. The APRI score was used to assess fibrosis. Cure was defined by an undetectable viral load 12 weeks after the end of treatment. Results: A total of 835 patients were included (sex ratio 1.55, mean age 50.5 ± 13.73, extremes 20 and 84 years). The 60 - 69 age group was the most represented. The mean APRI score was 0.42 ± 0.29, with extremes of 0.019 and 1.84. The mean viral load was 2,316,193.086 IU/mL. All subjects had good renal function. Cytolysis was absent in 70% of cases. Without genotyping, a pan-genotypic regimen was used in all patients: Sofosbuvir (400 mg)/Daclatasvir (60 mg). The cure rate was 99.4%, with good tolerability. However, four cases of failure were recorded out of the 668 patients who underwent follow-up HCV-PCR testing after 12 weeks of treatment. Conclusion: The Sofosbuvir/Daclatasvir regimen is highly effective, with an excellent safety profile. However, the still high cost of these molecules limits their accessibility to a large proportion of patients.
文摘The study carried out concerns the valorization of agricultural waste for the development of biosourced materials that can be used as insulation in homes. This article is devoted to the influence of gum arabic on the mechanical and thermal properties of clay soils in the town of Abéché. The mechanical tests were carried out using the CBR press equipped with two devices (bending device and compression device). Thermal property such as thermal conductivity was determined by the hot wire method and thermal resistance was derived by calculation. Thus, the tests were carried out on test pieces made from a mixture of clay and gum arabic in solution. The experimental program includes seven formulations (0%, 2%, 4%, 6%, 8%, 10% and 12%). The results obtained showed that the best flexural and compressive strengths are obtained by using gum arabic with a rate of 8% and a maximum stress of 4.3 MPa. In addition, the thermal results also showed that the thermal conductivity decreases when the percentage of gum arabic increases, which makes it possible to increase the thermal resistance, thus confirming the capacity of gum arabic to provide thermal insulation.
文摘With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brickwork in Abeche from a depth of 1 m, then using a clay brick-making press, 4 × 5 × 8 cm3 clay test tubes were made with 2%, 4%, 6% and 8% cow dung, and a 100% clay sample was used as a control. These samples underwent thermophysical characterization using the hot-wire method with a hot-plane option, yielding results that could improve thermophysical performance. The thermal conductivity of the test sample is in the order of 0.715 to 0.420 W/m. K, at 8% for cow dung, so the addition of cow dung as a percentage in the clay matrix enabled us to obtain various satisfactory thermal parameters.
文摘Background: Although hepatocellular carcinoma was historically considered an important scourge in Middle Africa, there is no publication describing this disease in Chad. Methods: We conducted a retrospective analysis of 219 patients with hepatocellular carcinoma (HCC) attending care at the University Reference Hospital of Ndjamena between 2007 and 2016. Results: This series of HCC was characterized by a male predominance (M:F = 2.4) with a mean tumor onset at the end of the fifth decade of life (49.9 ± 14.7 years). Tumors appear on a cirrhotic liver in 70% of cases and were already multifocal at diagnosis in two thirds of the patients. Alpha-fetoprotein was above the physiological threshold (10 ng/mL) in 73.4% of cases measured and above the so-called diagnostic level (400 ng/mL) in 53.4% of patients. The principal risk factor was chronic infection with hepatitis B virus, detected in 52.6% of cases. Patients seropositive for hepatitis C virus were infrequent (8.6%) and heavy alcohol intake was even less prevalent (5.9%). Remarkably, a very large subset of patients did not present any infectious or lifestyle risk factor (43.4%). Mean AFP values or fibrosis assessment scores are usually lower in these patients than in HBV-infected ones. Conclusions: The etiological spectrum of HCC is far from being fully established in Chad. Further epidemiological research is warranted to identify risk factors involved in a large proportion of cases. Exposure to aflatoxin B1 and dysmetabolic conditions affecting the liver have to be investigated as priority.
文摘Background: In comparison to other forms of chronic liver diseases, cirrhosis is generally poorly studied in sub Saharan Africa. In Chad, more particularly, no data are available despite the burden of liver diseases considered as the first cause of hospitalizations in the country. Methods: We conducted a retrospective analysis of 268 patients with liver cirrhosis attending care at the University Reference Hospital between 2007 and 2016. Results: This series of liver cirrhoses was characterized by a weak mal predominance (M:F = 1.7). The age of onset occurs significantly earlier in women than in men (40.6 ± 12.0 vs. 44.4 ± 13.4, p = 0.0171). The principal risk factor was persistent infection with hepatitis B virus (49% of cases) followed distantly by infection with hepatitis C virus (13%) and excessive alcohol consumption (10%). Men were more frequently carrying HBV surface antigen than women (65.6% vs 35.9% p = 0.0019). HBV-associated liver cirrhosis was overall more severe than diseases from other causes. A large proportion of cirrhosis (30%), observed primarily in women (48.1% vs 24.1%, p = 0.0036), was considered are cryptogenic. Conclusions: The etiological spectrum of liver cirrhosis remains to be properly defined in Chad. This lack of knowledge prevents the implementation of an efficient policy of prevention. A significant effort should be secured to characterize hitherto neglected infectious, lifestyle or genetic risk factors responsible of this form of terminal disease and improve subsequently liver health of local populations.
文摘The evolution of global mobile data over the past decades in broadcasting, Internet of Things (IoT), education, healthcare, commerce, and energy has put strong pressure on 3G/4G mobile networks to improve their service offerings. These generations of mobile networks were initially invented to meet the requirements of the above-mentioned applications. However, as the requirements in these applications continue to increase, new mobile technologies such as 5G (fifth generation), 5G and beyond (B5G, beyond fifth generation), and 6G (sixth generation) are still progressing and being experimented. These networks are very heterogeneous generations of mobile networks that will have to offer very high throughput per user, good energy efficiency, better traffic capacity per area, improved spectral efficiency, very low latency, and high mobility. To meet these requirements, the radio interface of future mobile networks will have to be flexible and rationalized the available frequency resources. Therefore, new modulation methods, access techniques and waveforms capable of supporting these technological changes are proposed. This review presents brief descriptions of the types of 5G, B5G, and 6G waveforms. The 5G consists of OFDM including its transmission techniques: generalized frequency division multiplexing (GFDM), filter bank based multi-carrier (FBMC), universal filtered multi-carrier (UFMC), and index modulation (IM). Meanwhile, the 6G covers orthogonal time frequency space (OTFS), orthogonal chirp division multiplexing (OCDM) and orthogonal time sequence multiplexing (OTSM). The networks’ potentialities, advantages, disadvantages, and future directions are outlined.
文摘The characteristics of viral hepatitis B and D co-infection are poorly documented in Chad. The aim of our study was to determine the prevalence of HBV/HDV co-infection and the characteristics of this co-infection. Materials and Methods: This was a retrospective study including all patients with chronic HBsAg carriers referred in our department from January 2014 to December 2018. Non-inclusion criteria were: absence of anti-HDV testing, presence of anti-viral hepatitis C or Human Immunodeficiency Virus antibodies or excessive alcohol consumption. The variables studied were age, sex, blood transaminase level, HBV DNA level, HDV RNA level, and liver fibrosis and activity score (Actitest Fibrotest). The prevalence of HDV and the characteristics of HDV/HBV co-infection were determined. Results: During the study period, 403 patients were seen in these two hospitals for chronic HBsAg carriage. Of these, 378 (75%) had performed the anti HDV assay. Anti-HDV antibodies were positive in 53 patients (14%). In multivariate analysis, HBV/HDV co-infected patients were less frequently HBeAg positive (5.4% vs. 28.1%;p = 0.0001), older (35 years vs. 32 years;p = 0.001), and more frequently had significant necrotic-inflammatory activity (3.9% vs. 3.2%;p = 0.031) compared with mono infected patients. Neither gender (76.9% male vs. 77.4% male;p = ns), nor viral load (median 530 IU/ml vs. 195 IU/ml;p = ns), nor significant liver fibrosis (35.1% vs. 47.1%;p = ns), nor transaminases (median 26 vs. 32 IU/ml) were different with mono infected patients. Conclusion: VHD is common in Chad. It is associated with increased hepatic necrotic-inflammatory activity.
文摘In this paper, we aim to solve a two compartmental mathematical model of ordinary differential equations for cardiovascular-respiratory system using a new recent method: Perturbation Iteration method. The description of this method for different order derivatives in the Taylor Series expansion is discussed. This method provides the solution in the form of an infinite series for ordinary differential equation. The efficiency of the method used is investigated by a comparison of Euler method and Runge Kutta. Numerical simulations of all these three methods are implemented in Matlab. The validation has been carried out by taking the values of determinant parameters of cardiovascular-respiratory system for a 30 years old woman who is supposed to make practice of three regular physical activities: Walking, Jogging and Running fast. The results are in good agreement with experimental data.
