Perceived risk of infection and death from COVID-19 among community members of low- and middle-income countries: A cross-sectional study [version 1; peer review: awaiting peer review]

Background: Risk perceptions of coronavirus disease 2019 (COVID-19) are considered important as they impact community health behaviors. The aim of this study was to determine the perceived risk of infection and death due to COVID-19 and to assess the factors associated with such risk perceptions among community members in low- and middle-income countries (LMICs) in Africa, Asia, and South America. Methods: An online cross-sectional study was conducted in 10 LMICs in Africa, Asia, and South America from February to May 2021. A questionnaire was utilized to assess the perceived risk of infection and death from COVID-19 and its plausible determinants. A logistic regression model was used to identify the factors associated with such risk perceptions. Results: A total of 1,646 responses were included in the analysis of the perceived risk of becoming infected and dying from COVID-19. Our data suggested that 36.4% of participants had a high perceived risk of COVID-19 infection, while only 22.4% had a perceived risk of dying from COVID-19. Being a woman, working in healthcare-related sectors, contracting pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, as well as seeing or reading about individuals infected with COVID-19 on social media or TV were all associated with a higher perceived risk of becoming infected with COVID-19. In addition, being a woman, elderly, having heart disease and pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, and seeing or reading about individuals infected with COVID-19 on social media or TV had a higher perceived risk of dying from COVID-19. Conclusions: The perceived risk of infection and death due to COVID-19 are relatively low among respondents; this suggests the need to conduct health campaigns to disseminate knowledge and information on the ongoing pandemic

Electric vehicle battery SOC estimation under different speed references

The present work aims to improve the traction chain system of a leisure electric vehicle equipped with a Li-S battery. For that, an equivalent circuit model of the battery was developed and implanted in the traction chain model in order to investigate the autonomy of the electric vehicle under different drive-cycles. The obtained results show a good quality of the studied vehicle in terms of autonomy and energy consumption

Effect of bacterial lipase on anaerobic co-digestion of slaughterhouse wastewater and grease in batch condition and continuous fixed-bed reactor

Abstract Background This study aimed to investigate the effects of bacterial lipase on biogas production of anaerobic co-digestion of slaughterhouse wastewater (SHWW) and hydrolyzed grease (HG). A neutrophilic Staphylococcus xylosus strain exhibiting lipolytic activity was used to perform microbial hydrolysis pretreatment of poultry slaughterhouse lipid rich waste. Results Optimum proportion of hydrolyzed grease was evaluated by determining biochemical methane potential. A high biogas production was observed in batch containing a mixture of slaughterhouse composed of 75% SHWW and 25% hydrolyzed grease leading to a biogas yield of 0.6 L/g COD introduced. Fixed bed reactor (FBR) results confirmed that the proportion of 25% of hydrolyzed grease gives the optimum condition for the digester performance. Biogas production was significantly high until an organic loading rate (OLR) of 2 g COD/L. d. Conclusion This study indicates that the use of biological pre-treatment and FBR for the co-digestion of SHWW and hydrolyzed grease is feasible and effective

Isolation and Characterization of Hydrocarbon-Degrading Yeast Strains from Petroleum Contaminated Industrial Wastewater

Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil but failed to grow on short-chain n-alkane and aromatic hydrocarbons. Growth measurement attributes of the isolates, using n-hexadecane, diesel oil, and crude oil as substrates, showed that strain HC1 had better degradation for hydrocarbon substrates than strain HC4. In conclusion, these yeast strains can be useful for the bioremediation process and decreasing petroleum pollution in wastewater contaminated with petroleum hydrocarbons

Marine Algal Extract as a Biostimulant to Improve Tolerance to Salinity in Lettuce Plants

The purpose of this study was to investigate the impact of marine algal extract as foliar spray on growth, physiological, mineral composition, different osmoprotectant levels, various parts of antioxidant system, and gene expression of greenhouse lettuce (Lactuca sativa L.) plants grown under saline conditions (50mM and 100mM). Through LC/MS analysis, the algal extract's phenolic composition was determined by its abundance in quinic acid, gallic acid, kaempferol and luteolin. The concentration of leaf proline increased while the biomass production, chlorophyll fluorescence, SPAD index and mineral composition all decreased as a result of salt stress. The salt-stress tolerance mechanism in lettuce involved the expression of genes that encode antioxidant enzymes, including LsSOD, LsCAT, and LsAPX, in both stressed and control plants, which demonstrates their important roles. The findings revealed that plants that were treated with marine algal extract had a greater ability to handle salt challenge, as evidenced by a significant (p < 0.05) increase in plant growth, SPAD index, Fv/Fm ratio, a better nutritional status in addinto a better osmoprotection against salt stress. Malondialdehyde level, Hydrogen peroxide and stability index levels were significantly decreased. Furthermore, the antioxidant system saw a significant improvement, as demonstrated by the increased activity of catalase (CAT), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) under moderate stress conditions (50mM) and more abundant LsCAT transcripts in the stressed plants.  Overall, our findings indicate that marine algal extract appears to be an effective biostimulant product for treating lettuce under saline conditions.Keywords: antioxidant enzymes, chlorophyll fluorescence, gene expression, growth performance, Lactuca sativa L., marine algal extract, mineral composition, osmoprotectants

Production, purification and biochemical characterization of a thermoactive, alkaline lipase from a newly isolated Serratia sp. W3 Tunisian strain

International audienc

Pilot-scale petroleum refinery wastewaters treatment systems: performance and microbial communities' analysis

This study evaluated firstly the performance of the Continuous Stirred Tank bioReactor system (CSTR) for the treatment of highly toxic petroleum refinery wastewaters at the pilot-scale. The reduction of the COD, BOD5, phenols, and the total petroleum hydrocarbon (TPH) reached 82.10%, 85.87%, 91.63%, and 81.11%, respectively at high hydraulic residence time (HRT = 10 days). Decreasing HRT to 5 and 2.5 days led to a decrease in the efficiency of the process and a decrease in biomass concentration was also observed (<1000 mg/l). We investigated to test Membrane Bioreactor (MBR) configuration inoculated with the same microbial consortium of CSTR. Therefore, the removal efficiency reached 89.14% of COD and biomass concentration increased to 2800 mg/l at HRT = 1 day. Microbial biomass showed high acclimatization to the toxic wastewater. Communities' abundance and composition in CSTR and MBR were then performed using culture-independents approaches (qPCR, Illumina Miseq sequencing, and DGGE) based on the 16S rRNA gene sequencing. Results showed that major genera affiliated with Betaproteobacteria and Gammaproteobacteria were commonly shared in both bioreactors. The MBR presented a higher bacterial abundance and diversity than the CSTR. Furthermore, dominant genera belonging to Alphaproteobacteria and Bacteroidetes were exclusively detected in CSTR and MBR, respectively. Six potential hydrocabonclastic bacteria were isolated from the CSTR. This study demonstrates the occurrence of specific acclimated bacterial communities in MBR different from those identified in CSTR, improving the petroleum hydrocarbon wastewater treatment. The results would be useful in developing an MBR system for treating toxic stripped wastewater at a larger scale