A green cross-linking method for the preparation of renewable threedimensional graphene sponges for efficient adsorption of Congo red dye

Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.

Palaeogene Sandstones of the Manika Plateau in Kolwezi (DR Congo): Sedimentological and Geochemical Characterization, Provenance, Palaeoalteration and Tectonic Context

This work presents a study of the Paleogene sandstones of the Manika plateau in Kolwezi, DR Congo. These sandstones belong to the “Grès polymorphes” group, which together with the overlying “Sables ocre” makes up the Kalahari Supergroup. Sedimentological and geochemical analyses have enabled us to characterize these sandstones and determine their origin, the conditions of their formation and the tectonic context in which they were developed. The results show that the sandstones are quartz arenites with a high level of mineralogical, textural and chemical maturity. They are recycled sandstones, formed in an intracratonic sedimentary basin, in the context of a passive continental margin, after a long fluvial transport of sediments. These sandstones initially come from intense alteration of magmatic rocks with felsic composition, mainly tonalite-trondhjemite-granodiorite (TTG) complexes, in hot, humid palaeoclimatic conditions and oxidizing environments.

Fatty Acid Composition of Hazelnut Kernel Oil from Coula edulis Collected in the Republic of Congo

Coula edulis is non-timber forest product (NTFP) used in Africa for its hazelnuts, which contain edible seeds with a demonstrated nutritional potential. However, there have been very few scientific studies of this species in the Republic of Congo. Thus, the aim of the current study was therefore to determine the fatty acid composition of the oil extracted from Coula edulis hazelnut seeds collected at random in the Republic of Congo. The oil was extracted using the Soxhlet method and its fatty acid composition was determined by gas chromatography. The extracted oil from Coula edulis hazelnut kernels is rich in monounsaturated fatty acids (95.28%), particularly oleic acid (94.5%), which classifies it as an oleic oil and gives it interesting nutritional and therapeutic properties. On the other hand, saturated fatty acids (4.15%) and polyunsaturated fatty acids (0.35%) are not well represented. Its low poly-unsaturated fatty acid content makes it more stable when stored at room temperature.

Congophilic fibrils in the glomeruli with polyclonal immunoglobulin gamma staining-another cause for diagnostic overlap:A case report

BACKGROUND Glomerulopathy with fibrillary deposits is not uncommon in routine nephropathology practice,with amyloidosis and fibrillary glomerulonephritis being the two most frequently encountered entities.Renal amyloid heavy and light chain(AHL)is relatively uncommon and its biopsy diagnosis is usually limited to cases that show strong equivalent staining for a single immunoglobulin(Ig)heavy chain and a single light chain,further supported by mass spectrometry(MS)and serum studies for monoclonal protein.But polyclonal light chain staining can pose a challenge.CASE SUMMARY Herein we present a challenging case of renal AHL with polyclonal and polytypic Ig gamma(IgG)staining pattern by immunofluorescence.The patient is a 62-yearold Caucasian male who presented to an outside institution with a serum creatinine of up to 8.1 mg/dL and nephrotic range proteinuria.Despite the finding of a polyclonal and polytypic staining pattern on immunofluorescence,ultrastructural study of the renal biopsy demonstrated the presence of fibrils with a mean diameter of 10 nm.Congo red was positive while DNAJB9 was negative.MS suggested a diagnosis of amyloid AHL type with IgG and lambda,but kappa light chains were also present supporting the immunofluorescence staining results.Serum immunofixation studies demonstrated IgG lambda monoclonal spike.The patient was started on chemotherapy.The chronic renal injury however was quite advanced and he ended up needing dialysis shortly after.CONCLUSION Tissue diagnosis of AHL amyloid can be tricky.Thorough confirmation using other available diagnostic techniques is recommended in such cases.

Epidemiological and Paraclinical Aspects of Helicobacter pylori Infection among Hepatitis B Virus Carriers in the Republic of Congo

Objective: Describe the epidemiological and paraclinical aspects of HP infection in hepatitis B virus carriers. Population and Method: This was a descriptive cross-sectional study running from January 1 to August 30, 2019, a period of 8 months. It took place in the Hospital Centers of the two major cities of Congo (Brazzaville and Pointe-Noire). The target population of our study consists of patients carrying HBV under antiviral treatment or not. Patients aged at least 18 years and consenting with a biological and morphological assessment were included. We did not include in our study patients taking or having taken antibiotics and/or PPIs less than 4 weeks ago. We excluded all patients who did not deposit fresh stools and those in whom stool extraction could not be done manually. The variables studied covered sociodemographic, clinical and paraclinical aspects. Data entry was done using Excel 8.0 software. Statistical analysis was carried out with SPSS 20.0 software. Results: During our study, we included 169 patients. The frequency of HPAG in the stools of HBV carriers in our study population was 63.9% (n = 109). Male patients represented 69% (n = 75) and female patients represented 31% (n = 34). The average age of the patients is 43.92 ± 13.51 years with extremes of 18 years and 80 years. Concerning profession, unemployed patients and those working in the private sector were the most represented in respectively 28.4% (n = 31) and 22.9% (n = 25) without statistical link. Households comprising between 4 - 10 people and the use of public latrines were the risk factors most represented in respectively 69% (n = 75) and 88% (n = 96) without statistical link. Clinically, hepatomegaly and signs of portal hypertension were most represented in 53% (n = 58) and 47% (n = 51). Biologically, HBV DNA was detectable in 60.5% of cases (n = 66).

Physicochemical and Bacteriological Profile of Bilanko and Ngamakala Peat Bog Soils (Republic of Congo)

Peatlands are unique and complex natural ecosystems that are part of the most important carbon reservoirs on our planet, home to a diversity of microorganisms responsible for fermentation, humification or peat. The aim is to understand chemical and biological indicators of peatland soils. This work aims to determine the physicochemical and bacteriological profile and lipolytic activity of soil bacteria in Bilanko peatlands. The bacterial profile with the production of lipases is carried out by classical microbiology techniques. The results show that the soils are moderately acidic with temperatures of 27.8˚C ± 0.01˚C for Bilanko and 27.1˚C ± 0.57˚C for Ngamakala. The electroconductivity (EC) varies from (9.52 ± 0.002) μS/cm to (39.01 ± 1.4) μS/cm with low turbidity of (2.04 ± 0.66) mg/L to (31.02 ± 0.84) mg/L and low ion concentrations with, however, a richness in phenolic compounds for Bilanko compared to Ngamakala. FMAT diversity ranged from (1.71 ± 0.88)∙104 UFC/g to (2.92 ± 0.07)∙105 UFC/g for Bilanko and (1.30 ± 0.73)∙104 UFC/g to (2.89 ± 0.06)∙104 UFC/g for Ngamakala. Bacillus loads ranged from (5.20 ± 1.40)∙103 CFU/g to (1.22 ± 0.13)∙104 CFU/g and from (1.11 ± 0.13)∙104 CFU/g to (9.20 ± 2.05)∙103 CFU/g;enterobacteria loads from (1.40 ± 0.76)∙103 CFU/g to (8.80 ± 1.73)∙103 CFU/g and from (1.01 ± 0.02)∙103 CFU/g to (9.20 ± 2.05)∙103 CFU/g;in Pseudomonas from 0 to (2.30 ± 0.53)∙102 CFU/g and from 0 to (8.90 ± 2.35)∙102 CFU/g for Bilanko and Ngamakala respectively. These results reveal a variation in bacterial similarity and distribution in the Bilanko and Ngamakala peat bogs.

Principle for the Installation of Accommodation for Sick guards in Public Health Establishments in Brazzaville in the Republic of Congo

The results of scientific studies of human social facts in the field of health show that the management of a patient should involve the patient’s entourage,whatever the status or size of the health establishment.In healthcare establishments in the Congo,the following are recognised as being responsible for medical care:specialist doctors,doctors,midwives,nurses and care assistants.The patient’s family and close friends are responsible for looking after the patient and financing care.The hospital infrastructure does not provide any space for the patient warden who accompany the patient during reception and hospitalisation.This makes Congolese hospitals inefficient for patient care.How can we integrate the function of the Sick guard and the assistance of the family,in order to reduce the mortality rate and repair the harm caused to patients requiring the presence of relatives during their stay in hospital,which is considered to be a dangerous place?This article examines the functional principles for configuring the space that patient warden would occupy in the patient care system.On the basis of a documentary analysis of sociological and architectural studies of existing facilities,this article proposes a typical accommodation model with the spaces needed to ensure the well-being and effectiveness of the patient warden with the patient.These are rooms with minimum space for 2 to 4 individual beds,equipped with toilets and showers.The accommodation has a dining area,kitchen and laundry facilities.In the future,this accommodation will become part of the hospital estate and may be occupied by orderlies and patient warden recruited by the hospital administration.

What Is the Impact of Ploughing on Eucalyptus Plantations in Bambou Mingali (Plateaux Batéké, Republic of Congo)?

Soil ploughing is an important stage in the preparation of planting, causing disturbance to the physical, chemical and biological properties of the soil. Soil ploughing can affect the availability of nutrients and water resources, and its effect can be short, medium or long-term. Soil ploughing accelerates surface heating and air circulation and encourages mineralisation by transforming organic matter into mineral salts, making nutrients soluble and accessible to plants. The aim of this study is to determine how soil ploughing affects the distribution of nutrients in the soil profile. The study focuses on nitrogen, carbon, phosphorus, calcium and magnesium, which are major elements of soil fertility on the Batéké plateaux in Congo. The results indicate that ploughing significantly modifies the distribution at depth des elements nutritifs: there is more accumulation at the surface than at depth (ei: nitrogen 1.34 t/ha ± 0.035 at 10 cm compared with 1.034 t/ha ± 0.098 at 50 cm) with a higher concentration of carbon (13.89 t/ha ± 0.87) followed by nitrogen (1.34 t/ha ± 0.035).

Investigating Non-Compliance with COVID-19 Vaccination through Hesitancy, Refusal, and Access Limitation: A Community-Based Survey from the Democratic Republic of the Congo

Introduction: Vaccination plays a pivotal role in mitigating the repercussions of the COVID-19 pandemic. However, vaccination campaigns encounter obstacles, especially in developing countries like the Democratic Republic of the Congo (DRC). This study aimed at investigating the roles of vaccine hesitancy, refusal, and access barriers, while identifying individual-level factors associated with non-vaccination in Mbujimayi, DRC. Methods: A community-based cross-sectional survey was conducted in three health districts and included 1496 residents. Attitudes and behaviors related to seeking COVID-19 vaccination were assessed using a standardized questionnaire. Hierarchical logistic regression modeling was used to assess factors potentially affecting non-compliance with vaccination. Results: Among participants (median age = 33, IQR = 23.3, M/F sex ratio = 0.7), 60% displayed misconceptions about COVID-19 or its vaccine, while only 35.2% perceived COVID-19 as a significant health threat. Vaccination coverage was estimated at 49.1% (95% CI: 47.5;52.6), with 71.8% of vaccinated individuals having received one dose. Among the unvaccinated individuals, 50.9% expressed no intention to be vaccinated in the future, citing hesitation (30.4%) or refusal (39.6%) mainly due to side effects or distrust of vaccines. Conversely, 32.7% of the unvaccinated persons expressed access barriers despite willingness to be vaccinated. Misconceptions about COVID-19 and its vaccines were the main drivers of vaccination non-compliance. Conclusion: These findings demonstrate significant vaccine non-compliance driven by hesitancy, refusal, and access barriers. Strategies to enhance vaccination coverage and pandemic preparedness should address misconceptions, sociodemographic barriers, and geographic disparities.

Coordination of Regulation Devices for Damping Power Oscillations in a Dynamic Disturbance Context: A Fuzzy Logic-Based Approach Applied to the Electrical Grid of the Republic of Congo

This article presents a fuzzy logic-based approach to coordinate the control devices of the power system, such as Power System Stabilizers (PSS) and Static Synchronous Compensators (STATCOM), to damp power oscillations caused by dynamic disturbances. At first, we used the Lyapunov method to study the dynamic stability of the power grid in the Republic of Congo. This method allowed us to analyze the eigenvalues of the state variable matrix and highlight the eigenvalues in the complex plane. Secondly, we proposed a fuzzy logic-based controller to account for uncertainties existing near the thresholds. The inputs to this controller are the generator speed and generator rotor angle. We demonstrated the effectiveness and feasibility of this fuzzy control by applying it to the power grid of the Republic of Congo, with three power stabilizers and two STATCOMs. .

Abdominoplasty, Liposuction and Brazilian Butt Lift (BBL) in Kinshasa in the Democratic Republic of Congo. My Experience in This Aesthetic Plastic Surgery with Black African Women in a Low-Income Country

Background: In low-income African countries, the demand and use of plastic surgery operations including abdominoplasty, liposuction and Brazilian butt lift (BBL) are increasing. The goal of this work is to present my experience and the challenges of this aesthetic plastic surgery among black African women. Material and Methods: A retrospective study was conducted about the abdominoplasties, liposuctions and Brazilian butt lift (BBL) which I operated in public and private hospitals at Kinshasa (Democratic Republic of Congo) in black African women. It covers a period of 13 years, going from December 1, 2010 to December 1, 2023. For this study, I had at least 6 months period (to Juin 1, 2024) to assess the occurrence of early and late postoperative complications. Results: I performed 84 abdominoplasties, 144 liposuctions and 23 Brazilian butt lifts (BBL). The average age at the time of abdominoplasty was 44 years with extremes ranging from 26 to 55 years and a concentration of cases (60.7%) in the age group of 40 to 49 years. The age group of 20 to 29 years old represented the lowest rate of requests for abdominoplasty (4.7%). Patients with a BMI of 30 to 2 were the majority (61.9%), followed by those between 25 to 2 (29.7%). 67.8% of patients were obese (BMI ≥ 30 kg/m2). The average age at the time of liposuction was 41 years with extremes ranging from 21 years to 69 years;and more than half of cases (68%) in the age group between 30 and 49 years. As for Brazilian butt lift (BBL), the average age was 33 years with extremes ranging from 24 to 42 years and a concentration of patients (91.3%) between 20 and 39 years. The immediate postoperative complications of abdominoplasties observed were: seroma in 7% of cases, hematoma and partial infection of the surgical site in 5% of cases. Pathological scars (hypertrophic, keloid) after abdominoplasties were observed in 9% of cases. The most common complication of liposuction was contour deformity. I observed 16 patients (11.1%) with soft-tissue depressions or elevations, skin panniculus or folds. For Brazalian Butt Lift (BBL), complications like asymmetry for 2 patients (8.9%), contour irregularities for 2 patients (8.9%), and excessive fat removal for 6 patients (26%), had observed. I have not recorded any cases of death or pulmonary embolism. Conclusion: I perform aesthetic plastic surgery procedures in black African women with a high socioeconomic standard of living compared to the average of the general population. The renunciation of planned surgery is motivated by the impossibility of paying the cost of the operation as well as by popular and religious perceptions regarding cosmetic surgery. The results of these aesthetic plastic surgery procedures carried out are very satisfactory for them. The challenges to overcome are mainly threefold: the unforeseeable complications of these cosmetic plastic surgery procedures, popular and religious perceptions of cosmetic surgery as well as the poverty of the population.

Study of the Impact of Climate Change on Water Resources in the Sangha Watershed at Ouesso Hydrological Station, Republic of the Congo-Brazzaville (1961-2020)

The Sangha River basin is the largest sub-basin of the Congo River basin, which drains the northern part of the Republic of the Congo-Brazzaville. It is the most important economic zone in this part of the country, with a strong timber industry, agriculture and hydroelectricity. The catchment also boasts the country’s third-largest river port, located in the town of Ouesso. Unfortunately, increasingly frequent low-water levels in recent years have led to a decline in river navigation and economic activities. So, the aim of this study is to show the effects of climate change over the last six decades in the Sangha watershed at Ouesso hydrological station, located in the north of the Republic of the Congo-Brazzaville, and elucidate its impact on water resources. To achieve this, several statistical and hydrological methods were used. The application of change-point or shift detection tests to flow series from 1961 to 2020 revealed variability in the hydrological cycle, characterized by two major phases of homogeneous flows: a wet surplus phase and a dry deficit phase. The results show one shift in flood flows in 1971 (Buishand test), one shift in yearly average flows or modules in 1971 (Pettitt test and Buishand test), and one shift in low-water flows in 1976, with all two tests. These disruptions were accompanied by a drop in flow of around 15.63%, 21.70% and 35.67%, on average, for floods, modules, and low-water, respectively, a drop in rainfall of around 9.6% and a rise in temperature of around 0.76?C. These flows show an overall downward trend. The calculated recession coefficients show that, over the entire study period, a recession occurred in March 1985.

Influence of Climate and Tectonics on the Crystallization of Carnallite and Related Salts in the Congolese Atlantic Basin during the Lower Cretaceous, Republic of Congo

Lithological, petrographic, and morphoscopic studies were conducted on cuttings and cores from three boreholes drilled in the Loemé salt, Kanga site, Republic of the Congo, to determine 1) the preferential conditions for crystallization of carnallite and associated salts and 2) to reconstruct paleoenvironmental and paleoclimatic conditions at the time of sedimentation. Sequential analysis of logs, sedimentary structures, carnallitite facies and associated salts concluded to the existence of a potassic carnallitite lagoon basin with low water cover, on a very wide and extensive plateau, affected by coastal waves and swells resulting from successive collapses. This basin evolved in two phases: confined and then open. The regular stratifications of halite, the rhythmicity of the halite-carnallitite elementary sequences are characteristic of salts that precipitated in relatively stable brines. These salts are therefore tectonosedimentary. The brecciated facies of the carnallitites sometimes associated with tachyhydrite result from the evolution of these deposits into salt crusts reworked by the surges into subaquatic allochemical gravelly cords under water. These crusts mark stages of partial and complete drying of the basin in a very hot and arid climate. Prolonged exposure of halite brines as well as their homogenization by surges accelerated evaporation and their abrupt evolution into carnallite brines obstructing the fossilization of sylvite. The precipitation of tachyhydrite marks the final stage of the successive complete drying of the basin.

Wood Density Determination with the Perspective to Decarbonisation of Tropical Forest Species from the Luki Biosphere Reserve in the Democratic Republic of the Congo

Specimens of the forest species such as Pentaclethra macrophylla, Petersianthus macrocarpus, Pycnanthus angolensis and Terminalia superba have been sampled from LUKI Biosphere reserve in the Democratic Republic of the Congo in order to determine their wood density with the perspective to decarbonisation. These parameters have been found out experimentally utilizing a drying technique in an oven including techniques of immersion in an Erlenmeyer full of water. The corresponding results indicated that the four species wood density is respectively 0.85, 0.80, 0.77 and 0.51. These preliminary results will be useful in our ongoing project on carbon dioxide absorption capacity of Congo rainforest tree species.

Epidemiological and Prognostic Aspects of Anemia during Heart Failure in Brazzaville (The Republic of the Congo)

To improve the management of patients with heart failure and anemia at the University Hospital of Brazzaville, a cross-sectional study of patients diagnosed with heart failure condition (left or global heart failure) was conducted over a period of nine months from January 1 to September 30, 2017. A total of 171 patients were included during the study period. Study participants were divided into two groups: Group A included patients with an additional anemic condition (n = 57) and Group NA patients without anemia (n = 114). Anemia was defined as a hemoglobin rate of < 12 g/dL for men and <11 g/dL for women. All eligible patients admitted to the Department of Cardiology were included in the study. The frequency of anemia was 33.3%, with a mean hemoglobin level of 9.4 ± 1.5 g/dL. Men accounted for 46.9% of cases (n = 79) and women 53.8% (n = 92). The mean age of eligible patients was 57.5 ± 16.5 years. Of these, 46.2% (n = 75) had a secondary educational level and 53.8% (n = 92) had a low socioeconomic status. Heart failure was global in 153 cases (89.5%). Patients were on NYHA III-IV functional class in 112 cases (65.5%), with a statistically significant difference between anemic and non-anemic patients (p = 0.0001). The main underlying heart diseases were dilated cardiomyopathy (75.1%), hypertensive heart disease (10.5%), ischemic heart disease (6.5%), and valvular disease (4.7%). The comparison between the two groups (A and NA) showed a longer hospital length of stay (18.4 ± 8.9 versus 12.9 ± 7.6 days;p = 0.00001) and a higher mortality rate (4 versus 2 deaths). The re-hospitalization rate was more important in group A (n = 4) than in group NA (n = 1). Anemia is a common condition in patients with heart failure. It worsens the clinical features and prognosis.

Aetiologic Factors of Anemia During Heart Failure in Brazzaville (The Republic of the Congo)

To contribute to improving the management of patients with heart failure and anemia in Brazzaville, a prospective and descriptive study was conducted in the University Hospital of Brazzaville for nine months (January 1st to September 30, 2017). Included 57 patients hospitalized for left or global heart failure and presenting anemia. Anemia was defined by an haemoglobin level < 12 g/dL in men and <11 g/dL in women. Proportionings of the reticulocytes rate, serum iron, ferritin, erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP), electrophoresis of proteins, and evaluation of renal function by glomerular filtration rate (GFR), as well as the treatments of heart failure, and the auxiliary therapeutic ones, in particular the antithrombotic drugs, allowed aetiologic research. They were 20 men (35%) and 37 women (65%), old on average of 59 ± 17 years. The average rate of haemoglobin was 11.4 ± 1.4 g/dL. Heart failure was de novo in 24 cases (42.1%), old in 33 cases (57.9%);it was global in 54 cases (94.7%).The maintenance treatment associated diuretics in 32 cases (97%), angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) in 31 cases (94%), beta-blockers in two cases (6.1%), digoxin in four cases (12.1%), aspirin in five cases (15.1%) and anti-vitamin K in four cases (12.1%). Anemia was microcytic hypochromic in 30 cases (52.6%), normocytic normochromic in 20 cases (35.1%), and macrocytic normochromic in one case (1.7%). The main aetiologic factors were hemodilution in 46 cases (80.7%), renal insufficiency in 30 cases (52.3%), inflammation in 29 cases (50.8%), and iron deficiency in one case (1.7%). The HIV serology, carried out in 11 cases, was negative. Anemia is a frequent comorbidity among heart failure patients. Aetiologic research remains difficult in our context, and its often multifactorial origin.

Post Debarking Response of Prunus africana (Hook. F) Kalkman (Rosaceae) Trees at Two Exploitation Sites in North Kivu (Eastern Democratic Republic of Congo)

Prunus africana is a species of great economic, medicinal and ecological importance. Due to its multiple uses, unsustainable exploitation methods and low regeneration capacity in tropical rainforests, this species is threatened with extinction. Present and exploited in the eastern part of DR Congo, knowledge of the dynamics of post-bark regeneration of Prunus africana remains fragmentary and poorly known. In North Kivu province, this species thrives in both afromontane forest and lowland tropical rainforest habitats. In order to contribute to the rational and sustainable exploitation of Prunus africana in this province, this paper was carried out with the objective of contributing to the knowledge of the dynamics of the regeneration of post-harvest bark of Prunus africana in two exploitation sites (low and high altitude). To achieve this objective, the inventory was conducted on 16 plots of 25 hectares each, with 8 plots per site. Dendrometric parameters (diameter at breast height (DBH), total tree height) and tree growth and regeneration parameters, i.e., stem bark thickness of the unharvested and harvested portions of the trees (bark reconstitution) were measured. A total of 716 barked stems of Prunus africana in 2016 in 25 hectares constituted the study sample. Results show that sites do not influence diameter at breast height of P. africana trees (p > 0.05) or total tree height. The bark diameter of harvested trees and the bark diameter of unharvested trees varied significantly by site (p 0.05). In contrast, the annual growth rate of bark differed with altitude;the highest rate was observed in trees growing at high altitude (2.97 ± 0.9 mm/yr) compared to 2.23 ± 0.74 mm/yr at low altitude. In view of these results, this study indicates that a half-rotation of 7 years could allow an effective reconstitution of the bark of Prunus africana at the second passage on the remaining side of the same stem.

Using Remote Sensing to Analyse the Role of Urbanization in the Transformation of Land-Use and Land Cover in Likasi Town (Haut-Katanga, DR Congo)

Environmental change is characterized as an alteration in the environment caused primarily by human activities and ecological processes that are natural. Given the fact that the southern part of the province of Haut-Katanga in the Democratic Republic of the Congo (DRC) is part of the African Copperbelt and has been a region of intense mining for decades, humans have affected the physical environment in various ways: such as overpopulation, suburbanization, wastage, deforestation. It is therefore important to track and control the changes in the area’s mining activities. This study aimed to analyze these changes using remote sensing techniques. Landsat satellite images from 2002 and 2022 were processed and classified to quantify changes in built-up area, agricultural land, and vegetation cover over the 20-year period. The classification results revealed sizable differences between the two time points, indicating considerable expansion of built-up land and declines in agricultural land and vegetation cover from 2002 to 2022 in Likasi. These findings provide evidence that urban growth has transformed the landscape in Likasi, likely at the expense of farmland and ecosystems. Further analysis of the remote sensing data could quantify the changes and model future trends to support sustainable land use planning. The land cover and land use analysis were performed with the assistance of the ERDAS 16.6.13 software by mapping LANDSAT data from two different years 2002 and 2022.

Outcome of Patients with Lower Limbs Deep Vein Thrombosis at the University Hospital of Brazzaville (The Republic of the Congo)

The aim of this study was to describe the characteristics of patients with deep vein thrombosis (DVT) of the pelvic limbs at the time of diagnosis, and their course after hospitalization, in order to improve the management of DVT in our context. This was a descriptive longitudinal study, based on cases of deep vein thrombosis recorded between 1 January 2015 and 30 September 2018, in the cardiology and internal medicine department of the Brazzaville University Hospital Centre. During the study period, 4678 patients were hospitalized, including 52 with DVT. Thirty-three were reassessed. The frequency of DVT was 1.1% and the average hospitalization rate was 13.9 cases/year. The 33 patients were divided into 20 women and 13 men (sex ratio: 0.65). The mean age of the patients was 51.4 ± 17.8 years (extremes: 16 and 85 years). The main aetiological factors were cancer (19.1%), sickle cell disease (3%) and HIV immunosuppression (3%). The predominant risk factors were: prolonged immobilization (42.9%), pregnancy, long travel and obesity in the same number of cases (n = 3, i.e. 14.2%). The DVT involved the left pelvic limb in 75.8% of cases. Anticoagulants were administered in all patients, and compression stockings were worn in 97% of cases. The mean time to re-evaluation was 10.9 ± 9.4 months (extremes: three and 35 months). The mean measurements of the limb where the thrombosis had occurred at diagnosis and reassessment showed a significant difference. Venous Doppler showed compressible veins (60.6%), varicosities (36.3%), incompressible veins (30.3%) and thrombus (21.2%). Complications were: post-phlebitic disease (42.4%), death (21.2%), pulmonary embolism (18.2%), recurrence (18.2%). The DVT remains relatively rare, and its conventional therapeutic management is satisfactory. Systematic venous Doppler ultrasound reassessment should enable patients at risk of recurrence to be identified.

Soil Seed Bank Characteristics of the Mbe and Nguela Shrub Savannas, and Implications for the Reforestation, Republic of Congo

The soil seed bank is an important source of restoration and resilience of disturbed ecosystems. This study evaluates the regeneration potential through the soil seed bank of the shrub savannas of Nguela and Mbe in order to predict the eventual dynamics. Three plots of 0.25 ha subdivided into four sub-plots of 0.015 ha have been installed in each savannah. In total, 48 samples of each savannah, i.e. 96 samples of both savannas, have been taken from the soil layers, 0 - 5 cm, 5 - 10 cm, 10 - 15 cm and 15 - 20 cm. Species diversity and abundance of the soil seed bank have been assessed after germination. The results reveal 167 seedlings belonging to 23 species in the Mbe savannah and 144 seedlings belonging to 14 species in the Nguela savannah. The total densities of the germinated seeds were respectively 463.63 seeds/m2 and 400 seeds/m2. Nevertheless, the 20 cm deep layers have illustrated themselves compared to the superficial layers with densities of 16.29 seeds/m2 and 21.66 seeds/m2, respectively, in the savannas of Mbe and Nguela. Herbaceous species largely dominated, with percentages of 91% and 100%, respectively, in the savannas of Mbe and Nguela. Alone, the Trema orientalis (L.) Blume species has been identified as woody species in the Mbe savannah. The greatest specific richness has been obtained in the first five centimeters of soil, with 21.73% and 28.57% of exclusive species, respectively, in the savannas of Mbe and Nguela. The results reveal that restoration through the soil seed bank would be limited to a single woody species found (T. orientalis). Consequently, the study suggests silvicultural interventions based on planting or enrichment techniques for sustainably managed savannas exposed to anthropogenic disturbances.