a b s t r a c tThe presence of Escherichia coli in environmental waters is considered as evidence of faecal contamination and is therefore commonly used as an indicator in both water quality and food safety analysis. The long period of time between sample collection and obtaining results from existing culture based methods means that contamination events may already impact public health by the time they are detected. The adoption of molecular based methods for E. coli could significantly reduce the time to detection. A new quantitative real-time PCR (qPCR) assay was developed to detect the ybbW gene sequence, which was found to be 100% exclusive and inclusive (specific and sensitive) for E. coli and directly compared for its ability to quantify E. coli in environmental waters against colony counts, quantitative real-time NASBA (qNASBA) targeting clpB and qPCR targeting uidA. Of the 87 E. coli strains tested, 100% were found to be ybbW positive, 94.2% were culture positive, 100% were clpB positive and 98.9% were uidA positive. The qPCR assays had a linear range of quantification over several orders of magnitude, and had high amplification efficiencies when using single isolates as a template. This compared favourably with qNASBA which showed poor linearity and amplification efficiency. When the assays were applied to environmental water samples, qNASBA was unable to reliably quantify E. coli while both qPCR assays were capable of predicting E. coli concentrations in environmental waters. This study highlights the inability of qNASBA targeting mRNA to quantify E. coli in environmental waters, and presents the first E. coli qPCR assay with 100% target exclusivity. The application of a highly exclusive and inclusive qPCR assay has the potential to allow water quality managers to reliably and rapidly detect and quantify E. coli and therefore take appropriate measures to reduce the risk to public health posed by faecal contamination.Crown

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Recently, the International Energy Agency (IEA) released a comprehensive roadmap for the global energy sector to achieve net-zero emission by 2050. Considering the sizeable share of (Sub-Sahara) Africa in the global population, the attainment of global energy sector net-zero emission is practically impossible without a commitment from African countries. Therefore, it is important to study and analyze feasible/sustainable ways to solve the energy/electricity poverty in Africa. In this paper, the energy poverty in Africa and the high renewable energy (RE) potential are reviewed. Beyond this, the generation of electricity from the abundant RE potential in this region is analyzed in hourly timestep. This study is novel as it proposes a Sub-Sahara Africa (SSA) central grid as one of the fastest/feasible solutions to the energy poverty problem in this region. The integration of a sizeable share of electric vehicles with the proposed central grid is also analyzed. This study aims to determine the RE electricity generation capacities, economic costs, and supply strategies required to balance the projected future electricity demand in SSA. The analysis presented in this study is done considering 2030 and 2040 as the targeted years of implementation. EnergyPLAN simulation program is used to simulate/analyze the generation of electricity for the central grid. The review of the energy poverty in SSA showed that the electricity access of all the countries in this region is less than 100%. The analysis of the proposed central RE grid system is a viable and sustainable option, however, it requires strategic financial planning for its implementation. The cheapest investment cost from all the case scenarios in this study is $298 billion. Considering the use of a single RE technology, wind power systems implementation by 2030 and 2040 are the most feasible options as they have the least economic costs. Overall, the integration of the existing/fossil-fueled power systems with RE technologies for the proposed central grid will be the cheapest/easiest pathway as it requires the least economic costs. While this does not require the integration of storage systems, it will help the SSA countries reduce their electricity sector carbon emission by 56.6% and 61.8% by 2030 and 2040 respectively.

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It has been brought to our attention that there is an error in the Methods, section 2.6 "Real-time PCR". The article as published states "Each reaction contained 12.5 ml of IQ SYBR Supermix con-taining reaction buffer, dNTPs, Taq polymerase and SYBR Green II DNA binding dye (Biorad), 9.5 ml of RT-PCR grade water (Agilent), 1 ml of each primer (final concentration 5 mM) and 1 ml of template DNA at 100 ng/ml; the final volume was 25 ml.".However this should be "Each reaction contained 12.5 ml of IQ SYBR Supermix con-taining reaction buffer, dNTPs, Taq polymerase and SYBR Green II DNA binding dye (Biorad), 9.5 ml of RT-PCR grade water (Agilent), 1 ml of each primer (final concentration 0.4 mM) and 1 ml of template DNA at 100 ng/ml; the final volume was 25 ml."