Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

Insight of Natural Compounds Halimane Diterpenoids against Mycobacterium tuberculosis: Virtual Screening, DFT, Drug-Likeness, and Molecular Dynamics Approach

In the purpose to design novel antituberculosis (anti-TB) drugs agents against Mycobacterium tuberculosis (Mtb), we have built a molecular library around 42 Halimane Diterpenoids isolated from natural sources. Two Mtb enzymes drug targets (Mtb Mycothiol S-transferase and Mtb Homoserine transacetylase) have been adopted. The pharmacological potential was investigated through molecular docking, molecular dynamics simulation, density functional theory (gas phase and water) and ADMET analysis. Our results indicate that (2R,5R,6S)-1,2,3,4,5,6,7,8-octahydro-5-((E)-5-hydroxy-3-methylpent-3-enyl)-1,1,5,6-tetramethylnaphtha-lene-2-ol (compound 20) has displays higher docking score with each of the selected drug targets. In addition, this molecule exhibits a satisfactory drug potential activity and a good chemical reactivity. Its improved kinetic stability in the Mtb Mycothiol S-transferase enzyme reflects its suitability as a novel inhibitor of Mtb growth. This molecule has displayed a good absorption potential. Our results also show that its passive passage of the intestinal permeability barrier is more effective than that of first-line treatments (ethambutol, isoniazid). In the same way, this anti-TB druglikeness has shown to be able to cross the blood brain barrier.

Cameroon Climate Predictions Using the SARIMA-LSTM Machine Learning Model: Adjustment of a Climate Model for the Sudano-Sahelian Zone of Cameroon

It is acknowledged today within the scientific community that two types of actions must be considered to limit global warming: mitigation actions by reducing GHG emissions, to contain the rate of global warming, and adaptation actions to adapt societies to Climate Change, to limit losses and damages [1] [2]. As far as adaptation actions are concerned, numerical simulation, due to its results, its costs which require less investment than tests carried out on complex mechanical structures, and its implementation facilities, appears to be a major step in the design and prediction of complex mechanical systems. However, despite the quality of the results obtained, biases and inaccuracies related to the structure of the models do exist. Therefore, there is a need to validate the results of this SARIMA-LSTM-digital learning model adjusted by a matching approach, “calculating-test”, in order to assess the quality of the results and the performance of the model. The methodology consists of exploiting two climatic databases (temperature and precipitation), one of which is in-situ and the other spatial, all derived from grid points. Data from the dot grids are processed and stored in specific formats and, through machine learning approaches, complex mathematical equations are worked out and interconnections within the climate system established. Through this mathematical approach, it is possible to predict the future climate of the Sudano-Sahelian zone of Cameroon and to propose adaptation strategies.

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.

Isometric Immersions of Lightlike Warped Product Manifolds

In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.

DETERMINISTIC HOMOGENIZATION OF QUASILINEAR DAMPED HYPERBOLIC EQUATIONS

Deterministic homogenization is studied for quasilinear monotone hyperbolic problems with a linear damping term. It is shown by the sigma-convergence method that the sequence of solutions to a class of multi-scale highly oscillatory hyperbolic problems converges to the solution to a homogenized quasilinear hyperbolic problem.

Deterministic Homogenization of Nonlinear Degenerate Elliptic Operators with Nonstandard Growth

We study the deterministic homogenization of nonlinear degenerate elliptic equations with nonstandard growth. One fundamental in this topic is to extend the classical compactness results of the E-convergence method to the Orlicz spaces. We also show that one can homogenize nonlinear Dirichlet problems in a general way by leaning on a simple abstract hypothesis contrary to what has been done in the determinstic homogenization theory.