No abstract

Background: Almost 60 million people are infected with and 25 million people have already died from HIV/AIDS. Sub-Saharan Africa is the region most affected, with 67% of all people living with HIV and 91% of all new infections amongst children and 14 million children orphaned by HIV-related deaths. HIV can be transmitted from a pregnant mother to her child during pregnancy, birth or breastfeeding. In South Africa (SA) the mother-to-child HIV transmission (MTCT) rate is under 4% at 4 to 8 weeks after birth since implementation of the most recent national prevention of MTCT (PMTCT) programme.Aim: This study sought to investigate the level of knowledge of nurses and doctors working at Odi Hospital in Tshwane, and whether they were putting the current PMTCT programme into practice.Methods: A descriptive cross-sectional survey was undertaken using self-administered questionnaires developed from the current PMTCT guidelines.Results: Of the 102 participants, 12 (12%) were doctors and 90 (88%) nurses, of whom 9 (9%) were male and 93 (91%) female. Mean knowledge percentage was 60.8% and mean practice percentage was 77%. Regarding knowledge, the question on HIV counselling and testing scored an average 93.1%, while that on doses of drugs used in the PMTCT guidelines scored 17.7%. For practice questions scores ranged from 71% to 82%.Conclusion: Nurses and doctors working at Odi Hospital knew that HIV counselling and testing is important and must be done for all mothers; however, they were unsure of the dosages of drugs used for PMTCT. More than two-thirds of the doctors and nurses reported practising the PMTCT guidelines, but as their knowledge was inadequate their practice may not be appropriate.

The ability to accurately predict natural gas prices asides being beneficial to stakeholders of the natural gas market also have positive economic impacts on energy management and environmental sustainability. This paper explores the application of machine learning algorithms for the purpose of accurately predicting monthly natural gas spot prices. Henry Hub natural gas spot price data from January 2001 to November 2021 were utilized alongside four machine learning algorithms namely; Artificial Neural Networks (ANN), Support Vector Regression (SVR), Random Forest Regressor and Gradient Boosting Machine (GBM). The models were trained with 11 variables with 80% of the dataset utilized for training and 20% for testing purposes. A 10-fold cross validation technique was implemented for model validation purposes. The accuracy of each model was evaluated using the Root Mean Square error metric. After model evaluation, all four models generated distinct results, with the Artificial Neural Network model having the most accurate prediction of all four models.

Background: Nevirapine, a component of antiretroviral therapy (ART) in resource-limited settings is known for auto-induction of metabolism, and thus is prescribed at half therapeutic dose until day14 ('lead-in period'), and then escalated to full dose. However, young children have higher clearance rates, suggesting that dosing strategy based on adult studies may not be appropriate in children. We aimed to determine plasma nevirapine concentrations achieved during the first month among children initiated on nevirapine-containing ART Methods & Materials: ART-naïve HIV-infected children, initiating ART were included in this prospective study. Plasma nevirapine trough levels were analyzed in duplicate (with additional 10% repeats for quality control) by high performance liquid chromatography (HPLC) (lowest detection limit 0.062 g/ml) at days 7, 14 (lead-in period) and 28 (full dose) after ART initiation. Baseline transmitted drug resistance genotyping, serial CD4 count and viral load was done.Results: Among 28 children aged 2-12 years initiated on nevirapine-based ART between 2013-2014, six were excluded due to drug toxicity, and two were transferred out within first month. Among 20 children included in the study, 19 reported >95% adherence at all study visits. Transmitted drug resistance was seen in 5(10%) children (V90I, K103N, K101E, E138G, Y188L, M41L, L210W, T215Y). Median trough nevirapine concentration was 4.83g/ml (IQR 3.48-6.06) at day 7 of ART initiation, 3.35g/ml (IQR 2.06-7.91) at day 14 (lead-in period), and 7.97g/ml (IQR 5.55-10.66) on day 28 (p= 0.018). During the lead-in period 40% (8/20; 15% at day 7, 35% at day 14) of children failed to achieve therapeutic levels of >3 g/ml, while after dose escalation, only 5% (1/20) had low therapeutic levels. Low trough nevirapine levels was not significantly associated with age, viral load, CD4 count or transmitted drug resistance.Conclusion: Our results showed significantly lower therapeutic concentrations of nevirapine during the lead-in period in young children initiating nevirapine-based ART in India. Given nevirapine's low genetic barrier, sub-therapeutic levels during the early high viremic period can lead to later drug resistance development and treatment failure. Long-term drug resistance studies among viral quasispecies can determine the true effect of early subtherapeutic concentrations