Petroleum geological characteristics and exploration targets of the oil-rich sags in the Central and West African Rift System

Based on seismic,drilling,and source rock analysis data,the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System(CWARS)are discussed.The study shows that the Central African Rift System mainly develops high-quality lacustrine source rocks in the Lower Cretaceous,and the West African Rift System mainly develops high-quality terrigenous organic matter-rich marine source rocks in the Upper Cretaceous,and the two types of source rocks provide a material basis for the enrichment of oil and gas in the CWARS.Multiple sets of reservoir rocks including fractured basement and three sets of regional cap rocks in the Lower Cretaceous,the Upper Cretaceous,and the Paleogene are developed in the CWARS.Since the Late Mesozoic,due to the geodynamic factors including the dextral strike-slip movement of the Central African Shear Zone,the basins in different directions of the CWARS differ in terms of rifting stages,intervals of regional cap rocks,trap types and accumulation models.The NE-SW trending basins have mainly preserved one stage of rifting in the Early Cretaceous,with regional cap rocks developed in the Lower Cretaceous strata,forming traps of reverse anticlines,flower-shaped structures and basement buried hill,and two types of hydrocarbon accumulation models of"source and reservoir in the same formation,and accumulation inside source rocks"and"up-source and down-reservoir,and accumulation below source rocks".The NW–SE basins are characterized by multiple rifting stages superimposition,with the development of regional cap rocks in the Upper Cretaceous and Paleogene,forming traps of draping anticlines,faulted anticlines,antithetic fault blocks and the accumulation model of"down-source and up-reservoir,and accumulation above source rocks".The combination of reservoir and cap rocks inside source rocks of basins with multiple superimposed rifting stages,as well as the lithologic reservoirs and the shale oil inside source rocks of strong inversion basins are important fields for future exploration in basins of the CWARS.

Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

African swine fever(ASF)continues to cause enormous economic loss to the global pig industry.Since there is no safe and effective vaccine,accurate and timely diagnosis of ASF is essential to implement control measures.Indirect immunofluorescence assay(IFA)is a gold standard serological method recommended by the World Organization for Animal Health(WOAH).In this study,we used primary fetal kidney cells to establish a wild boar cell line(BK2258)that supported the efficient replication of ASF virus(ASFV)SD/DY-I/21 and showed visible cytopathic effect(CPE).Moreover,using BK2258,we established a sensitive and specific IFA for ASFV antibody detection.To standardize and evaluate the performance of this assay,we used serum samples from pigs infected with the low virulent genotype I SD/DY-I/21 and genotype II HLJ/HRB1/20,and immunized with the vaccine candidate HLJ/18-7GD,field samples,and negative serum samples.The IFA reacted with the ASFV-positive sera and displayed bright fluorescence foci.There was no non-specific green fluorescence due to cellular senescence or other cell damage-causing factors.Compared to a commercial indirect enzyme-linked immunosorbent assay(iELISA),ASFV antibodies were detected 1–4 days earlier using our IFA.The detection limits of the IFA and iELISA for the same ASFV-antibody positive serum samples were 1:25,600 and 1:6,400,respectively,indicating that the IFA is more sensitive than iELISA.The newly established IFA was highly specific and did not cross-react with sera positive for six other important porcine pathogens(i.e.,Classical swine fever virus(CSFV),Porcine reproductive and respiratory syndrome virus(PRRSV),Porcme circovirus type 2(PCV2),Pseudorabies virus(PRV),Foot-and-Mouth disease virus type O(FMDV/O),and Porcine epidemic diarrhea virus(PEDV)).This study thus provides a sensitive,specific,and reliable detection method that is suitable for the serological diagnosis of ASF.

A Hybrid Classification and Identification of Pneumonia Using African Buffalo Optimization and CNN from Chest X-Ray Images

An illness known as pneumonia causes inflammation in the lungs.Since there is so much information available fromvarious X-ray images,diagnosing pneumonia has typically proven challenging.To improve image quality and speed up the diagnosis of pneumonia,numerous approaches have been devised.To date,several methods have been employed to identify pneumonia.The Convolutional Neural Network(CNN)has achieved outstanding success in identifying and diagnosing diseases in the fields of medicine and radiology.However,these methods are complex,inefficient,and imprecise to analyze a big number of datasets.In this paper,a new hybrid method for the automatic classification and identification of Pneumonia from chest X-ray images is proposed.The proposed method(ABOCNN)utilized theAfrican BuffaloOptimization(ABO)algorithmto enhanceCNNperformance and accuracy.The Weinmed filter is employed for pre-processing to eliminate unwanted noises from chest X-ray images,followed by feature extraction using the Grey Level Co-Occurrence Matrix(GLCM)approach.Relevant features are then selected from the dataset using the ABO algorithm,and ultimately,high-performance deep learning using the CNN approach is introduced for the classification and identification of Pneumonia.Experimental results on various datasets showed that,when contrasted to other approaches,the ABO-CNN outperforms them all for the classification tasks.The proposed method exhibits superior values like 96.95%,88%,86%,and 86%for accuracy,precision,recall,and F1-score,respectively.

APOBEC3G Role on HIV Infection in Africa: A Systematic Review

The highly active antiretroviral treatment (HAART) has allowed people living with HIV to live longer with a better quality of life. However, toxicity and the emergence of drug resistance arise from HAART use. Therefore, new antiretroviral therapy is needed since no cure or vaccine is available against HIV. Virus-host interaction has been proven to be important in the last decade. Host factors such as the C-C chemokine receptor type 5 (CCR5), a receptor used by HIV to penetrate host cells, have led to the discovery of the Maraviroc, which is an antiretroviral medication used in the United States. In contrast, other factors like C-X-C Motif Chemokine Receptor 4 (CXCR4) and the Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G), a potent host defense factor against HIV, is under investigation. APOBEC3G antiviral activity remains a possible therapeutic target against HIV. This systematic review aimed to synthesize the available evidence on the role of APOBEC3G polymorphisms and their expression on HIV infection disease progression in Africa. We used Web of Science, PubMed, Embase, and Google Scholar and searched for relevant publications in French or English reporting on APOBEC3G polymorphisms association with HIV infection in African populations from January 2009 to May 2023. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyzes) was used to process for reporting systematic review. Fifteen studies were included, of which seven were on APOBEC3G polymorphisms and eight were on APOBEC3G expression. Among the APOBEC3G polymorphisms, the most studied was H186R or rs8177832. The average of the minor allele frequency of H186R of APOBEC3G available for the studies included in this study was 0.29 with a 95% CI (0.172;0.401) and varied from 0.108 reported in Uganda to 0.47 recorded from Burkina Faso. The polymorphism H186R was not associated with HIV status in Southern Africa. However, the referent allele of H186R was protective against HIV infection in Western Central Africa, while in West Africa, it was the minor allele (G) of H186R which was protective against HIV. This review warrants a need to increase research on APOBEC3G, from its variants to its hypermutations on the continent with an essential variety of HIV-1 subtypes, to impact the research on A3G-based anti-HIV strategies.

Antibiotic Resistance Profile of Salmonella Strains Isolated at the National Clinical Biology and Public Health Laboratory in Bangui, Central African Republic

In Africa, each year, there are estimated to be more than 91 million cases of salmonellosis and 137,000 cases of death. The problem of antibiotic resistance in Salmonella strains is a threat to public health. The objective of this study is to evaluate the antibiotic resistance profile of Salmonella strains isolated in biological products analyzed at the National Laboratory of Clinical Biology and Public Health (NLCBPH) in Bangui. This is, therefore, a cross-sectional study with a descriptive aim, running from January to December 2022. It focused on the strains of Salmonella isolated and identified in stools, urines, and blood samples. For each strain of Salmonella isolated, an antibiogram was carried out following the recommendations of the French Society of Microbiology (CASFM, 2022). A total of 93 strains of Salmonella have been recorded. The age group 0 - 9 years was 29% and that of >50 years was 11%. The median age of patients was 30 years with a minimum of 1 and a maximum of 78 years. The female gender was more represented at 52.69% than the male gender at 47.31%, i.e. a sex ratio of 0.89 (M/F). Salmonella strains were much more isolated in stools at 62% followed by urines at 29% and blood at 6%. Salmonella arizonae strains were more represented with 52%. Salmonella strains have a resistance rate to Tetracycline of 62.37% followed by Penicillins of 50%. The rate of multi-antibiotic resistance of the Salmonella strains isolated represented 48.38%. Salmonella spp. strains were multi-resistant at 58.69% followed by Salmonella arizonae strains at 47.91%. There is a significant association between the different families of antibiotics and Salmonella strains (p < 0.05). According to the results obtained, Penicillins, Phenicoles, and Cyclins had a high rate of resistance on Salmonella strains. No strain-producing Broad Spectrum Beta-lactamase has been isolated. Salmonella strains represent a zoonotic health danger, constitute a public health problem and remain a current subject. This germ is resistant to the antibiotics used. It is, therefore, essential to emphasize monitoring the resistance of these germs in the Central African Republic (CAR) to improve the health of the population.

Between Euthanasia and Dysthanasia: The Ethical Issue of Sedation in the Terminal Phase of Illness

Background: Deep sedation, euthanasia and therapeutic relentlessness lead us today to rethink the paradigm of life and the contingency of human existence. Between therapeutic relentlessness, the unreasonable care which uses heavy therapeutic means which are often disproportionate to the expected benefit, namely keeping alive a patient whose condition is considered medically hopeless;and euthanasia which would precipitate the process of death would be sedation in the terminal phase of the illness. Should doctors and families of comatose patients decide the “life” and “death” of their patients? For anti-euthanasia associations, doctors, relatives of terminally ill patients and the State itself, if they accept the principle of euthanasia, they are “murderers”, while for pro-euthanasists, the dignity of the human being would recommend that the days of patients in situations considered critical be shortened, to avoid unnecessary suffering and humiliation. Methods: A systematic review of the literature was carried out to identify relevant articles relating to euthanasia, dysthanasia and sedation in the terminal phase of illness. The search was conducted in French or English in three databases: PubMed, Google Scholar and Science Direct. Objectives: The objectives of this article are: 1) define the terminologies and concepts of palliative sedation, deep sedation, deep and continuous sedation until death, euthanasia and dysthanasia;2) present aspects of the meaning of life and the human person in African cultures;and 3) propose an ethical reflection on the value of life. Results: After precisely defining the concepts of euthanasia, dysthanasia and sedation, this research presented the African anthropological and ethical approach to the mysteries of life and death. Conclusion: With this in mind, the golden rule of medicine always remains as such “Primum non nocere”.

Daqing Oilfield Sets Sail on a New Voyage under the Belt and Road Initiative

In"Lonely Planet",there is a saying that goes,"Often when people think of Africa,they are actually thinking of Tanzania".There are the African savannas,the great animal migrations,and Kilimanjaro,bringing together the most stunning landscapes of this mysterious African continent.When we had the opportunity to come to this beautiful country,although we didn’t see these magnificent landscapes,we met with azure coastlines,white beaches,red earth,and baobab trees.Furthermore,after 6 years of tracking,bidding,and negotiating,we won a project led by Western owners amidst competition with 11 global contractors.

Mass Screening Using Antigenic and Molecular Diagnostic Tests of COVID-19 in Bangui at the Beginning of the Second Wave in July 2021

Objective: COVID-19 surveillance was established as early as March 2020 in the Central African Republic (CAR), after the WHO statement relating to the identification of several cases outside China. However, given the non-performing molecular biology technical platform in many developing countries in sub-Saharan Africa, the second wave promised to be surprising and formidable. In this context, a mass survey was launched in Bangui to determine the prevalence of COVID-19. Patients and Methods: From March 18 to April 2, 2021, a mass screening campaign took place in tourist places, companies and the main hospital infrastructures. Nasopharyngeal swab samples were collected from participants with and without symptoms of Influenza-like illness (ILI) and stored in VTM tubes. The Ag (COVID-19) and RT-PCR tests were carried out in Bangui at the LNBCSP. The sequencing of RT-PCR SARS-CoV-2 positives was carried out at the INRB. Results: We included 1480 participants of whom 33 (2.23%) were SARS-COV-2 positive, of whom 24 were male and 9 female. This sex difference was statistically significant (p = 0.012) as the sex ratio M/F was 1.09. Sampling sites located in the 1st arrondissement were the most prolific (p = 0.006) and were sequenced. In addition to the analysis of the 33 samples from the predefined sites under study, 17 control sequences from the provinces generated during the same period are added. We detected 2 Variants Of Concern (VOC) including the predominant B.1.620 (43.86%) followed by B.1.1.7 or Alpha (5.10%). Conclusion: The study showed the importance of surveillance and the availability of means of diagnosis of COVID-19. The identified risk factors were sex and sampling site. This study has shown the importance of setting up sentinel sites for COVID-19 surveillance in all regions of the country and the appropriate use of the anti-COVID-19 vaccine.

Contribution to the Study of the Incidence of Post-Streptococcal Complications in Republic Central African Republic from 2015 to 2018

Introduction: Acute rheumatic fever (AAR) is a non-suppurative complication of late infection by group A. Infections due to streptococci remain a public health problem in the Central African Republic. The present study aims to determine the incidence rate of AAR cases and its complications. Methodology: This was a retrospective and analytical study over a period of 4 years (from January 2015 to December 2018) at the National Laboratory of Clinical Biology and Public Health (LNBCSP) in Bangui. It focused on samples concerning the diagnosis of AAR and patient files seen in consultation in the capital’s reference health establishments. Laboratory registers and patient consultation files were used to collect data. They were entered into Excel 2010 to be analyzed with Epi Info 7. A univariate analysis by logistic regression, Ficher’s exact test, and chi2 at the 5% threshold (p Results: We analyzed 94 cases meeting Jones’s criteria. The ages of the patients ranged from 18 to 85 years (mean age 52 years and mode 45 years). The incidence rate of AAR for the female sex was higher than that of the male sex during the study period (p > 0.05). It went from 166.6 in 2015 to 200 in 2016 and 2018 cases of AAR per 1000 people per year. The average incidence rate was 296.18 cases of AAR per 1000 people per year. The average incidence rate was 223.5 cases of AAR per 1000 people per year for joint damage. Joint damage represented 80.85% (RR = 0.62;Chi2 = 4.88;95% CI [0.39-0.97];p Conclusion: The study allowed data on the impact rate and complications of the AAR in Bangui. Special attention to data management will help produce a complete result on the problem. Joint complications predominated. Sustaining an effective surveillance system and preventing infection would help reduce the risk of AAR occurrence.

Neurological Manifestations of Vitamin B12 Deficiency: About a Case

The authors report a case of deficient sensory neuropathy secondary to vitamin B12 deficiency, diagnosed in the neurology department of the Sino-Central African Friendship University Hospital in Bangui. The diagnosis was made possible by electroneuromyography which showed subclinical neurological damage associated with hematological damage (anemia). Through this observation, we recall the diagnostic criteria of the disease in a context of difficult medical practice. .

Population Decline

The Double Take column looks at a single topic from an African and Chinese perspective.This month we discuss the decline in population that is taking place in some countries including China.

SNAPSHOTS OF NOTABLE BOOKS ON AFRICA

Ubuntu Edited by PAUL NNODIM&AUSTIN OKIGBO Leuven University Press Ubuntu,an African philosophical tradition,embodies the capacity for one human to empathise with another,encapsulating African humanism,communalism,and belonging.The late Archbishop Desmond Tutu foresaw its resonance with the moral sensibilities of black South Africans in the 1990s,making it the foundational ethical framework for navigating a new era of reconciliation and forgiveness post-apartheid,amidst a backdrop of historical racial violence.

Pockets of Prosperity

As African countries look to enhance their manufacturing industries and speed up industrialisation,they are learning valuable insights from the development experience of industrial parks worldwide,particularly from China.

Africa’s Industrialisation Journey

China and African countries are in different development stages,but they have the same mission of pursuing industrialisation.History shows that industrialisation is the inevitable path for economic development,as well as the key for African countries to realise inclusive and sustainable development,create employment,alleviate poverty and improve people’s livelihoods.

Cost Optimization of Steel Beam-to-Column Connections using AVOA

The joint-bolt-African Vulture optimization algorithm(AVOA)model is proposed for the design of building connections to improve the stability of steel beam-to-column connections.For this algorithm,the type of steel is first determined,and the number of bolts needed by the corresponding steel type is referenced in Eurocode 3.Then,the bearing capacity of the joint can be calculated.The joint-bolt-AVOA model is established by substituting the bolt number required by the steel into the algorithm to obtain the optimal bolt number required while ensuring joint stability.The results show that the number of bolts required by the joint-bolt-AVOA model based on the stability of steel is lower than that calculated by Eurocode 3.Therefore,AVOA can effectively optimize the number of bolts needed in building connections and save resources.

Influence of Continental Atmospheric Forcing on the Decadal Variability of the West African Monsoon

The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20th century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.

A multiplex real-time PCR assay for simultaneous detection of classical swine fever virus,African swine fever virus,and atypical porcine pestivirus

With the implementation of the C-strain vaccine,classical swine fever(CSF) has been under control in China,which is currently in a chronic atypical epidemic situation.African swine fever(ASF) emerged in China in 2018 and spread quickly across the country.It is presently occurring sporadically due to the lack of commercial vaccines and farmers’ increased awareness of biosafety.Atypical porcine pestivirus(APPV) was first detected in Guangdong Province,China,in 2016,which mainly harms piglets and has a local epidemic situation in southern China.These three diseases have similar clinical symptoms in pig herds,which cause considerable losses to the pig industry.They are difficult to be distinguished only by clinical diagnosis.Therefore,developing an early and accurate simultaneous detection and differential diagnosis of the diseases induced by these viruses is essential.In this study,three pairs of specific primers and Taq-man probes were designed from highly conserved genomic regions of CSFV(5’ UTR),African swine fever virus(ASFV)(B646L),and APPV(5’ UTR),followed by the optimization of reaction conditions to establish a multiplex real-time PCR detection assay.The results showed that the method did not cross-react with other swine pathogens(porcine circovirus type 2(PCV2),porcine reproductive and respiratory syndrome virus(PRRSV),foot-and-mouth disease virus(FMDV),pseudorabies virus(PRV),porcine parvovirus(PPV),and bovine viral diarrhea virus BVDV).The sensitivity results showed that CSFV,ASFV,and APPV could be detected as low as 1 copy μL–1;the repeatability results showed that the intra-assay and interassay coefficient of variation of ASFV,CSFV,and APPV was less than 1%.Twenty-two virus samples were detected by the multiplex real-time PCR,compared with national standard diagnostic and patented method assay for CSF(GB/T 27540–2011),ASF(GB/T 18648–2020),and APPV(CN108611442A),respectively.The sensitivity of this triple real-time PCR for CSFV,ASFV,and APPV was almost the same,and the compliance results were the same(100%).A total of 451 clinical samples were detected,and the results showed that the positive rates of CSFV,ASFV,and APPV were 0.22% (1/451),1.3%(6/451),and 0%(0/451),respectively.This assay provides a valuale tool for rapid detection and accurate diagnosis of CSFV,ASFV,and APPV.

Identification of two novel linear epitopes on the p30 protein of African swine fever virus

African swine fever(ASF) is a hemorrhagic disease caused by African swine fever virus(ASFV), which belongs to the Asfarviridae family. ASF has become prevalent in Africa since it was first reported in Kenya in 1921(Rowlands et al. 2008;Costard et al. 2009). In 1957, it was introduced to Portugal in Europe, after which ASFV rapidly spread to other European countries and has already been eradicated in several countries except Sardinia(Mur et al. 2016). In 2007, ASF was introduced to Georgia and has continued its spread to other countries in Europe(Smietanka et al. 2016;Kolbasov et al. 2018;Garigliany et al. 2019;Linden et al. 2019). In China, an ASF outbreak was first reported on August 3, 2018 in a pig farm in Shenyang, Liaoning Province(Zhou et al. 2018). Since then, the dramatic spread of ASF throughout China has caused huge economic losses to the swine industry(Jiang et al. 2021).

Signatures of positive selection for local adaptation of African native cattle populations:A review

Cattle are central to the lives and diverse cultures of African people.It has played a crucial role in providing valuable protein for billions of households and sources of income and employment for producers and other actors in the livestock value chains.The long-term natural selection of African cattle typically signals signatures in the genome,contributes to high genetic differentiations across breeds.This has enabled them to develop unique adaptive traits to cope with inadequate feed supply,high temperatures,high internal and external parasites,and diseases.However,these unique cattle genetic resources are threatened by indiscriminate cross-breeding,breed replacements with exotic cosmopolitan breeds,and climate change pressures.Although there are no functional genomics studies,recent advancements in genotyping and sequencing technologies have identified and annotated limited functional genes and causal variants associated with unique adaptive and economical traits of African cattle populations.These genome-wide variants serve as candidates for breed improvement and support conservation efforts for endangered cattle breeds against future climate changes.Therefore,this review plans to collate comprehensive information on the identified selection footprints to support genomic studies in African cattle to confirm the validity of the results and provide a framework for further genetic association and QTL fine mapping studies.

Distribution patterns of fire regime in the Pendjari Biosphere Reserve, West Africa

Pendjari Biosphere Reserve(PBR),a primary component of the W-Arly-Pendjari transboundary biosphere reserve,represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa.This savannah ecosystem has long been affected by fire,which is the main ecological driver for the annual rhythm of life in the reserve.Understanding the fire distribution patterns will help to improve its management plan in the region.This study explores the fire regime in the PRB during 2001–2021 in terms of burned area,seasonality,fire frequency,and mean fire return interval(MFRI)by analysing moderate resolution imaging spectroradiometer(MODIS)burned area product.Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season(November–December).The last two fire seasons(2019–2020 and 2020–2021)recorded the highest areas burned in the PBR out of the twenty fire seasons studied.During the twenty years period,8.2%of the reserve burned every 10–11 months and 11.5%burned annually.The largest part of the reserve burned every one to two years(63.1%),while 8.3%burned every two to four years,5.8%burned every four to ten years,and 1.9%burned every ten to twenty years.Only 1.3%of the entire area did not fire during the whole study period.Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%.The MFRI(MFRI<2.00 a)was low in grasslands,shrub savannah,tree savannah,woodland savannah,and rock vegetation.Fire regime must be maintained to preserve the integrity of the PBR.In this context,we suggest applying early fire in tree and woodland savannahs to lower grass height,and late dry season fires every two to three years in shrub savannah to limit the expansion of shrubs and bushes.We propose a laissez-faire system in areas in woodland savannah where the fire frequency is sufficient to allow tree growth.Our findings highlight the utility of remote sensing in defining the geographical and temporal patterns of fire in the PBR and could help to manage this important fire prone area.