11 research outputs found

    Voltammetric Determination of Penicillin G in Sodium Dodecyl Sulfate/acetate Buffer Media on Glassy Carbon Electrode

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    The presence of residues of penicillin in food products like milk and meat of animal origin exerts negative impact on public health such as drug resistance diseases and severe allergic responses. This work reports development of a simple voltammetric method for detection of penicillin using sodium dodecyl sulfate (SDS) in acetate buffer solution (ABS) on glassy carbon electrode. Addition of SDS to the penicillin G containing acetate buffer solution (ABS) was found to enhance the voltammetric oxidation current signal by about 5 times with insignificant shift of the oxidation potentials. Using cyclic voltammetry, the oxidation potentials for penicillin G were found to be 1.65V vs. Ag/AgCl in SDS/ABS, pH 4.5 and 1.60V vs. Ag/AgCl in ABS, pH 4.5. The diffusion coefficients for penicillin G were found to be 6.01x10-7 cm2/sec and 1.39x10-6 cm2/sec in ABS, pH 4.5 and SDS/ABS, pH 4.5 respectively. Linear concentration range were also investigated using square wave voltammetry and found to lie in the range of 1.25 – 15µM penicillin G in SDS/ABS, pH 4.5 and 2.5 – 10µM penicillin G in ABS, pH 4.5.Limits of detection were also found to be 1.25µM and 2.5µM penicillin G in SDS/ABS, pH 4.5 and ABS, pH 4.5 respectively while limits of quantitation were 3.75µM penicillin G in SDS/ABS, pH 4.5 and 7.5µM penicillin G in ABS, pH 4.5. Possible interferants like Na+, K+, Zn2+, Ca2+, Fe3+, Cl-, NO3-, PO43- and SO42- did not have any significant effect on the anodic currents and oxidation potentials of the penicillin G. These results show that the developed method is sensitive enough for use in the analysis of penicillin G in diverse real samples

    Square Wave Voltammetric Determination of Penicillin V in Sodium Dodecyl Sulfate Containing Media on Glassy Carbon Electrode

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    The effect of adding sodium dodecyl sulfate (SDS), a surface-active agent to acetate buffer solution containing penicillin V was investigated. The voltammetric responses of penicillin V on glassy carbon electrode was a function of the concentration of penicillin V, surfactant and pH. Addition of SDS to the penicillin V containing acetate buffer solution (ABS) was found to enhance the voltammetric oxidation current signal by about 10 times with insignificant shift of the oxidation potentials. With this electrochemical method, the optimal pH and SDS concentration were found to be pH 4.5 and 0.347M respectively. Using cyclic voltammetry, the oxidation potential for penicillin V were found to be 1.61V vs. Ag/AgCl in SDS/ABS, pH 4.5 and 1.55V vs. Ag/AgCl in ABS, pH 4.5. Linear concentration range were also investigated using square wave voltammetry and found to lie in the range of 0.04 – 34.6µM penicillin V in SDS/ABS, pH 4.5 and 3.5 – 14.0µM penicillin V in ABS, pH 4.5. Limits of detection were also found to be 0.04µM penicillin V in SDS/ABS, pH 4.5 and 3.5µM penicillin V in ABS, pH 4.5 and limits of quantitation were 0.12µM penicillin V in SDS/ABS, pH 4.5 and 14µM penicillin V in ABS, pH 4.5.Foreign substances like Na+, K+, Mg2+, Zn2+, Ca2+, Fe3+, Cu2+, Cl-, NO3-, PO43- and SO42- did not have any significant effect on the voltammetric currents of penicillin V. These results confirm that this electrochemical method is sensitive enough to be used in the determination of penicillin V in diverse environmental and clinical samples

    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

    Get PDF
    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

    Upgrading biogas using Eburru zeolitic rocks and other adsorbent materials to remove carbon dioxide and hydrogen sulphide

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    The trace amounts of carbon dioxide and hydrogen sulfide in raw biogas lower its calorific value,cause corrosion and make it hard to compress biogas into the cylinder. Raw biogas was obtainedfrom anaerobic digestion of cow dung and market wastes. The gas was stored in tubes or urine bagbefore upgrading. Natural zeolite rocks, maize cobs, steel wire, desulphurizer, and worn-out tyreswere used as the upgrade materials. The composition of biogas was recorded before and afterupgrading using a GP180 portable biogas analyzer from Henan, China. The measured level of rawbiogas was 0.0227% H2S, >20% CO2 and 52-56% CH4. The most efficient upgrade materials werezeolite rocks with upgrade levels of 89–93% methane. The total removal using zeolite wasobserved to be 75% CO2 and 95.34% H2S. The morphological structures of zeolitic rocks accountfor its higher upgrading properties compared to other materials. In addition, the porosity in theserocks mean that CO2 and H2S were adsorbed resulting in high CH4 levels in the upgraded biogas.Other adsorbents showed upgrading properties with removal rates above 70% for both H2S andCO2. Keywords: Biogas, Upgrading, Natural zeolite, Bio-methan

    Morphological and Genetic Diversity of Rhizobia Nodulating Cowpea (Vigna unguiculata L.) from Agricultural Soils of Lower Eastern Kenya

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    Limited nitrogen (N) content in the soil is a major challenge to sustainable and high crop production in many developing countries. The nitrogen fixing symbiosis of legumes with rhizobia plays an important role in supplying sufficient N for legumes and subsequent nonleguminous crops. To identify rhizobia strains which are suitable for bioinoculant production, characterization of rhizobia is a prerequisite. The objective of this study was to assess the morphological and genetic diversity of rhizobia that nodulates cowpea in agricultural soils of lower eastern Kenya. Twenty-eight rhizobia isolates were recovered from soil samples collected from farmers’ fields in Machakos, Makueni, and Kitui counties in lower eastern Kenya and characterized based on morphological characteristics. Thirteen representative isolates were selected and characterized using BOX repetitive element PCR fingerprinting. Based on the dendrogram generated from morphological characteristics, the test isolates were distributed into two major clusters at a similarity of 75%. Phylogenetic tree, based on BOX repetitive element PCR, grouped the isolates into two clusters at 90% similarity level. The clustering of the isolates did not show a relationship to the origin of soil samples, although the isolates were genetically diverse. This study is a prerequisite to the selection of suitable cowpea rhizobia to develop bioinoculants for sustainable crop production in Kenya

    Sensitivity of SARS-CoV-2 B.1.1.7 to mRNA vaccine-elicited antibodies

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    Transmission of SARS-CoV-2 is uncontrolled in many parts of the world; control is compounded in some areas by the higher transmission potential of the B.1.1.7 variant1, which has now been reported in 94 countries. It is unclear whether the response of the virus to vaccines against SARS-CoV-2 on the basis of the prototypic strain will be affected by the mutations found in B.1.1.7. Here we assess the immune responses of individuals after vaccination with the mRNA-based vaccine BNT162b22. We measured neutralizing antibody responses after the first and second immunizations using pseudoviruses that expressed the wild-type spike protein or a mutated spike protein that contained the eight amino acid changes found in the B.1.1.7 variant. The sera from individuals who received the vaccine exhibited a broad range of neutralizing titres against the wild-type pseudoviruses that were modestly reduced against the B.1.1.7 variant. This reduction was also evident in sera from some patients who had recovered from COVID-19. Decreased neutralization of the B.1.1.7 variant was also observed for monoclonal antibodies that target the N-terminal domain (9 out of 10) and the receptor-binding motif (5 out of 31), but not for monoclonal antibodies that recognize the receptor-binding domain that bind outside the receptor-binding motif. Introduction of the mutation that encodes the E484K substitution in the B.1.1.7 background to reflect a newly emerged variant of concern (VOC 202102/02) led to a more-substantial loss of neutralizing activity by vaccine-elicited antibodies and monoclonal antibodies (19 out of 31) compared with the loss of neutralizing activity conferred by the mutations in B.1.1.7 alone. The emergence of the E484K substitution in a B.1.1.7 background represents a threat to the efficacy of the BNT162b2 vaccine

    SARS-CoV-2 evolution during treatment of chronic infection

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    The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for virus infection through the engagement of the human ACE2 protein1 and is a major antibody target. Here we show that chronic infection with SARS-CoV-2 leads to viral evolution and reduced sensitivity to neutralizing antibodies in an immunosuppressed individual treated with convalescent plasma, by generating whole-genome ultra-deep sequences for 23 time points that span 101 days and using in vitro techniques to characterize the mutations revealed by sequencing. There was little change in the overall structure of the viral population after two courses of remdesivir during the first 57 days. However, after convalescent plasma therapy, we observed large, dynamic shifts in the viral population, with the emergence of a dominant viral strain that contained a substitution (D796H) in the S2 subunit and a deletion (ΔH69/ΔV70) in the S1 N-terminal domain of the spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype were reduced in frequency, before returning during a final, unsuccessful course of convalescent plasma treatment. In vitro, the spike double mutant bearing both ΔH69/ΔV70 and D796H conferred modestly decreased sensitivity to convalescent plasma, while maintaining infectivity levels that were similar to the wild-type virus.The spike substitution mutant D796H appeared to be the main contributor to the decreased susceptibility to neutralizing antibodies, but this mutation resulted in an infectivity defect. The spike deletion mutant ΔH69/ΔV70 had a twofold higher level of infectivity than wild-type SARS-CoV-2, possibly compensating for the reduced infectivity of the D796H mutation. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy, which is associated with the emergence of viral variants that show evidence of reduced susceptibility to neutralizing antibodies in immunosuppressed individuals
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