Predictive modelling and optimization of an airlift bioreactor for selenite removal from wastewater using artificial neural networks and particle swarm optimization.

Selenite (Se4+) is the most toxic of all the oxyanion forms of selenium. In this study, a feed forward back propagation (BP) based artificial neural network (ANN) model was developed for a fungal pelleted airlift bioreactor (ALR) system treating selenite-laden wastewater. The performance of the bioreactor, i.e., selenite removal efficiency (REselenite) (%) was predicted through two input parameters, namely, the influent selenite concentration (ICselenite) (10 mg/L - 60 mg/L) and hydraulic retention time (HRT) (24 h - 72 h). After training and testing with 96 sets of data points using the Levenberg-Marquardt algorithm, a multi-layer perceptron model (2-10-1) was established. High values of the correlation coefficient (0.96 ≤ R ≤ 0.98), along with low root mean square error (1.72 ≤ RMSE ≤ 2.81) and mean absolute percentage error (1.67 ≤ MAPE ≤ 2.67), clearly demonstrate the accuracy of the ANN model (> 96%) when compared to the experimental data. To ensure an efficient and economically feasible operation of the ALR, the process parameters were optimized using the particle swarm optimization (PSO) algorithm coupled with the neural model. The REselenite was maximized while minimizing the HRT for a preferably higher range of ICselenite. Thus, the most favourable optimum conditions were suggested as: ICselenite - 50.45 mg/L and HRT - 24 h, resulting in REselenite of 69.4%. Overall, it can be inferred that ANN models can successfully substitute knowledge-based models to predict the REselenite in an ALR, and the process parameters can be effectively optimized using PSO.

The association between food groups and childhood anemia in Zambia, based on the analysis of Zambia Demographic and Health Survey 2018.

High prevalence of anemia among children has been an important public health concern globally. In Zambia, the prevalence of anemia among children aged 6-59 months was 58%. Previous studies have suggested that feeding a variety of food prevents anemia. However, it is not yet determined if out of several food groups available locally, some foods have played crucial roles in anemia among young children. The objective of this study was to find out the food groups that were associated with childhood anemia among Zambian children aged 6-59 months. We have obtained the individual- level data related to health and nutrition of the Zambia Demographic Health Survey (ZDHS) 2018 with permission. Children's feeding, demographic, and household information were analyzed using logistic regression models. Children who consumed food made from grains (AOR:1.2; 95%CI: 1.01-1.46; p=0.044) and cheese or food made from milk (AOR:2.7; 95%CI: 1.19-6.00; p=0.018) showed relatively higher prevalence of anemia than those who did not. Additionally, malnutrition, mother's anemia and education, and area of living were also significantly associated with prevalence of anemia. Most common food in Zambia is food made from grain. Grain consists of phytic acids which can prevent iron absorption. This is a potential reason for the highlevel anemia among children. Dephytinization strategies should be considered through further studies.

Selenite removal from wastewater using fungal pelleted airlift bioreactor.

This study investigated the removal of selenite from wastewater using the fungus Asergillus niger KP isolated from a laboratory scale inverse fluidized bed bioreactor. The effect of different carbon sources and initial selenite concentration on fungal growth, pellet formation and selenite removal was first examined in a batch system. The fungal strain showed a maximum selenite removal efficiency of 86% in the batch system. Analysis of the fungal pellets by field-emission scanning electron microscopy, field-emission transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed the formation of spherical-shaped elemental selenium nanoparticles of size 65-100 nm. An increase in the initial selenite concentration in the media resulted in compact pellets with smooth hyphae structure, whereas the fungal pellets contained hair like hyphae structure when grown in the absence of selenite. Besides, a high initial selenite concentration reduced biomass growth and selenite removal from solution. Using an airlift reactor with fungal pellets, operated under continuous mode, a maximum selenite removal of 94.3% was achieved at 10 mg L-1 of influent selenite concentration and 72 h HRT (hydraulic retention time). Overall, this study demonstrated very good potential of the fungal-pelleted airlift bioreactor system for removal of selenite from wastewater. Graphical abstract.

Impact of a massive earthquake on adherence to antiretroviral therapy, mental health, and treatment failure among people living with HIV in Nepal.

INTRODUCTION: The April 2015 Nepal earthquake resulted in more than 8,700 deaths and 22,000 casualties including damage to health facilities. The impact of this situation on chronic conditions such as human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) may become a long-lasting public health threat. Therefore, the objectives of this study were i) to assess the association of antiretroviral therapy (ART) adherence with mental health problems, and social behaviors, ii) to examine factors affecting treatment failure, and iii) to investigate changes in ART adherence and post-traumatic stress disorder (PTSD) among people living with HIV 6 and 12 months after the disaster. METHODS: Study was conducted 6 months after the earthquake in 2015 with a sample size of 305 earthquake victims with HIV and followed after 12 months of the earthquake. A logistic regression analysis was used to examine relationships, while a paired t-test analysis was conducted to assess changes in adherence to ART and PTSD level at 6 months and 12 months after earthquake. RESULTS: In the earthquake, 5.2% of the participants lost their family member. Approximately 44% of participants had earthquake-PTSD symptoms and 50% experienced HIV stigma. PTSD and HIV status disclosure were significantly associated with adherence to ART, while HIV stigma and religion were associated with treatment failure. PTSD and adherence levels to ART were significantly improved over the 6-month period. CONCLUSION: Awareness programs for general public to eliminate HIV stigma; promote psychosocial counseling to earthquake victims living with HIV in order to reduce PTSD will contribute to maintaining optimal ART adherence and to prevent treatment failure.

Genotypic Characterization of Human Immunodeficiency Virus Type 1 Derived from Antiretroviral Drug-Treated Individuals Residing in Earthquake-Affected Areas in Nepal.

Molecular epidemiological data on human immunodeficiency virus type 1 (HIV-1) are limited in Nepal and have not been available in areas affected by the April 2015 earthquake. Therefore, we conducted a genotypic study on HIV-1 genes derived from individuals on antiretroviral therapy residing in 14 districts in Nepal highly affected by the earthquake. HIV-1 genomic fragments were amplified from 40 blood samples of HIV treatment-failure individuals, and a sequencing analysis was performed on these genes. In the 40 samples, 29 protease, 32 reverse transcriptase, 25 gag, and 21 env genes were sequenced. HIV-1 subtyping revealed that subtype C (84.2%, 32/38) was the major subtype prevalent in the region, while CRF01_AE (7.9%, 3/38) and other recombinant forms (7.9%, 3/38) were also detected. In addition, major drug resistance mutations were identified in 21.9% (7/32) of samples, indicating the possible emergence of HIV-1 drug resistance in earthquake-affected areas in Nepal.