An electrocatalytic screen-printed amperometric sensor for the selective measurement of thiamine (Vitamin B1) in food supplements

An electrocatalytic screen-printed sensor has been investigated for the measurement of the biologically important biomolecule vitamin B1 (thiamine) for the first time in food supplements. Under basic conditions, the vitamin was converted to its electrochemically active thiolate anion species. It was shown that an electrocatalytic oxidation reaction occurred with the screen-printed carbon electrode containing the mediator cobalt phthalocyanine (CoPC-SPCE). This had the advantage of producing an analytical response current at an operating potential of 0 V vs. Ag/AgCl compared to +0.34 V obtained with plain SPCEs. This resulted in improved selectivity and limit of detection. Detailed studies on the underlying mechanism occurring with the sensor are reported in this paper. A linear response was obtained between 0.1 and 20 µg mL −1 , which was suitable for the quantification of the vitamin in two commercial products containing vitamin B1. The mean recovery for a multivitamin tablet with a declared content of 5 mg was 101% (coefficient of variation (CV) of 9.6%). A multivitamin drink, which had a much lower concentration of vitamin B1 (0.22 mg/100 mL), gave a mean recovery of 93.3% (CV 7.2%). These results indicate that our sensor holds promise for quality control of food supplements and other food types

Studies towards the development of a novel, screen-printed carbon-based, biosensor for the measurement of polyunsaturated fatty acids

This paper describes the design, development and characterisation of an electrochemical biosensor for the measurement of linoleic and α-linolenic acid, as representative free polyunsaturated fatty acids (PUFAs), that may be implicated in food safety and food quality. Initial cyclic voltammetric studies were performed with solutions that contained enzyme-generated hydroperoxides of the two PUFAs. These were examined with plain screen-printed carbon electrodes (SPCEs) and screen-printed carbon electrodes containing the electrocatalyst cobalt phthalocyanine (CoPC). The electrocatalytic oxidation peaks obtained with the latter occurred at potentials about 300 mV lower than the those obtained by direct oxidation with the plain SPCEs and were better defined; as these attributes would lead to better selectivity and sensitivity for fatty acid determinations, the CoPC-SPCEs were used in the fabrication of amperometric biosensors. The enzyme lipoxygenase (LOX) was immobilised on the surface of these devices using the crosslinking agent glutaraldehyde. These biosensors were optimised for the measurement of linoleic and α-linolenic acid using amperometry in stirred solution; the optimum conditions were deduced by studying the effect of enzyme loading, pH and temperature on the amperometric responses. These responses were examined over the concentration range 2.0 to 20 µM and the results indicated that the following conditions were optimal: LOX loading 15 units; pH 8.0; temperature 37 °C. Low concentration calibration studies were performed with the two PUFAs and it was shown that the steady state currents were linear between 0.2 and 10 µM for linoleic acid and 0.2 and 10 µM for α-linolenic acid; the detection limits were 24 and 100 nM, respectively. The precision (coefficient of variation, n = 6) was 5.3% for α-linoleic acid and 3.3% for linoleic acid, which were calculated from the steady state current following additions (n = 6) of 0.2 µM PUFA. These results demonstrate that the novel amperometric biosensor holds promise for determining whether foods contain acceptable levels of free fatty acids

Gas chromatography mass spectrometry (GC-MS) quantification of metabolites in stool using13 C labelled compounds

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. It has become increasingly important to qualitatively and quantitatively assess the volatile metabolites in a range of bodily fluids for use in monitoring health. There has been relatively little work on the quantitative analysis of compounds, particularly with respect to the effects of ethnicity or geographic location. A novel method for the quantification of compounds in stool using13 C labelled compounds as internal standards is presented. Using thermal desorption gas chromatography mass spectrometry, stool samples from 38 healthy volunteers were analysed. The13 C labelled compounds, acetone, ethyl butanoate, ethanoic acid, butanoic acid, 3-methylbutanoic acid, and indole, were added as internal standards. This process mimics the solubility characteristics of the compounds and thus the method was able to quantify the compounds within the solid stool. In total, 15 compounds were quantified: Dimethyl sulphide (26–25,626 ng/g), acetone (442–3006 ng/g), ethyl butanoate (39–2468 ng/g), ethyl 2-methylbutanoate (0.3–180 ng/g), dimethyl disulphide (35–1303 ng/g), 1-octen-3-one (12 ng/g), dimethyl trisulphide (10–410 ng/g), 1-octen-3-ol (0.4–58 ng/g), ethanoic acid (672–12,963 ng/g), butanoic acid (2493–11,553 ng/g), 3-methylbutanoic acid (64–8262 ng/g), pentanoic acid (88–21,886 ng/g), indole (290–5477 ng/g), and 3-methyl indole (37–3483 ng/g). Moreover, by altering the pH of the stool to pH 13 in conjunction with the addition of13 C trimethylamine, the method was successful in detecting and quantifying trimethylamine for the first time in stool samples (range 40–5312 ng/g). Statistical analysis revealed that samples from U.K. origin had five significantly different compounds (ethyl butanoate, 1-octen-3-ol, ethanoic acid, butanoic acid, pentanoic acid, and indole) from those of South American origin. However, there were no significant differences between vegetarian and omnivore samples. These findings are supported by pre-existing literature evidence. Moreover, we have tentatively identified 12 compounds previously not reported as having been found in stool

The Histone Deacetylase Inhibitor Romidepsin Spares Normal Tissues While Acting as an Effective Radiosensitizer in Bladder Tumors in Vivo

Funding Information: This work was funded by Cancer Research UK (CRUK; C5255/A23755). J.L.R. was funded by CRUK (project grant C15140/A19817). C.K.T. was funded by a CRUK DPhil Research Training and Support Grant, the Balliol College Alfred Douglas Stone Scholarship, and the University of Oxford Clarendon Fund. S.K. was funded by a CRUK/MRC Oxford Institute of Radiation Oncology CRUK studentship.Peer reviewedPublisher PD

Moving from ‘what we know works’ to ‘what we do in practice’::An evidence overview of implementation and diffusion of innovation in transition to adulthood for care experienced young people

Global research has shown that most young people who are care experienced are not prepared to transition to independent living at 18 years of age and require support into early adulthood. We used rigorous systematic methods to identify English‐based peer reviewed and grey literature describing innovations relevant to care experienced young people as they transition into adulthood, with a focus upon lessons for their implementation and diffusion. We synthesised the evidence narratively and organise data linked to seven key areas important to the transition to adulthood: (1) Health and well‐being; (2) relationships; (3) education and training; (4) employment; (5) participation in society; (6) accommodation; (7) other. Twenty‐five papers met our inclusion criteria. This review has found that, whilst there are a broad spectrum of innovations taking place within the social care environment for care experienced young people to support their transition into adulthood, there exists limited insight into how best to support implementation and diffusion of evidence‐based innovation. We drew upon the ‘Consolidated Framework for Implementation Research’, developed in the setting of clinical service delivery, to highlight challenges in implementing and diffusing evidence‐based innovation for care experienced young people transitioning into adulthood

Screen-printed carbon based biosensors and their applications in agri-food safety

This review focuses on the ways in which screen-printed carbon electrodes have been tailored with different biorecognition elements, including enzymes, antibodies, and aptamers, often with other modifiers, such as mediators and nanoparticles, to produce electrochemical biosensors for a variety of analytes of importance in agri-food safety. Emphasis is placed on the strategies of biosensor fabrication and the performance characteristics of the devices. As well as biosensors for a range of analytes in different agri-food matrices, we have also included reports on novel devices that have potential in agri-food safety but as yet have not been applied in this area

Schizophrenia polygenic risk and experiences of childhood adversity: a systematic review and meta-analysis

Background and Hypothesis Schizophrenia has been robustly associated with multiple genetic and environmental risk factors. Childhood adversity is one of the most widely replicated environmental risk factors for schizophrenia, but it is unclear if schizophrenia genetic risk alleles contribute to this association. Study Design In this systematic review and meta-analysis, we assessed the evidence for gene-environment correlation (genes influence likelihood of environmental exposure) between schizophrenia polygenic risk score (PRS) and reported childhood adversity. We also assessed the evidence for a gene-environment interaction (genes influence sensitivity to environmental exposure) in relation to the outcome of schizophrenia and/or psychosis. This study was registered on PROSPERO (CRD42020182812). Following PRISMA guidelines, a search for relevant literature was conducted using Cochrane, MEDLINE, PsycINFO, Web of Science, and Scopus databases until February 2022. All studies that examined the association between schizophrenia PRS and childhood adversity were included. Study Results Seventeen of 650 identified studies met the inclusion criteria and were assessed against the Newcastle-Ottawa Scale for quality. The meta-analysis found evidence for gene-environment correlation between schizophrenia PRS and childhood adversity (r = .02; 95% CI = 0.01, 0.03; P = .001), but the effect was small and therefore likely to explain only a small proportion of the association between childhood adversity and psychosis. The 4 studies that investigated a gene-environment interaction between schizophrenia PRS and childhood adversity in increasing risk of psychosis reported inconsistent results. Conclusions These findings suggest that a gene-environment correlation could explain a small proportion of the relationship between reported childhood adversity and psychosis