Chemical modification and characterisation of horseradish peroxidase and its derivatives for use in environmental applications

The biochemistry and molecular properties o f the widely-used horseradish peroxidase (HRP) are reviewed. The applications of HRP in diagnostics, sensors and waste treatment are also surveyed. The research aims were to stabilise HRP by chemical modification to ascertain the characteristics of stabilised derivatives and to explore the capabilities of these derivatives in waste treatment applications. Assay methods for HRP activity were compared and thermoinactivation experiments were undertaken using a variety of conditions in order to devise workable, reproducible protocols for routine use. Systematic chemical modification of the available reactive HRP amino residues (Arg, Tyr and Lys) were performed. Arginine and tyrosine modified derivatives yielded little gain in stability Modification of lysine residues with cyclic anhydrides of aromatic carboxylic acids was undertaken. Of the compounds used, only phthalic anhydride yielded a thermally stabilised HRP (PA HRP). The overall stability characteristics of this derivative were investigated fully together with previously reported crosslinked HRP modifications. The tolerances of these two derivatives towards heat, organic solvents, hydrogen peroxide, pH and dénaturants was enhanced. Both were immobilised on adipic acid dihydrazide-agarose (AADH-A). The stabilities of the immobilised, modified HRPs were compared with the modified-only counterparts. Unfolding of native and both modified HRPs were investigated using urea, guanidine chloride (GnCl), EDTA and heat. Unfolding over time was monitored using fluorescence and binding of the hydrophobic probe Nile Red. Results of the two methods agreed closely. Attempts were made to fragment the HRP polypeptide so as to demonstrate the presence of crosslinks and, possibly, to identify the modified Lys residues. Unfortunately these experiments proved inconclusive. It was shown that recombinant HRP which, lacks the carbohydrate moiety, could withstand a chemical modification and be stabilised in a similar manner to the plant HRP. A kinetic investigation of the HRP forms took place. Binding of the inhibitor BHA was found to be slightly less in the case of PA HRP. The pre-steady state and steady state kinetics of the HRPs using a variety of substrates were found to be in close agreement with each other. The significance of these results is discussed. The use of both modified HRPs in waste treatment was explored. Modified HRP was as effective as native in the precipitation of phenols at 37 °C. Modified HRPs were more effective than the native at higher temperature where the native is inactivated. In the bleaching of dyes, modified HRPs were as effective as the native. Thus, a new stabilised chemically modified form of HRP (PA HRP) has been described and the capabilities of this and the EG HRP in two distinct types of wastewater treatment have been characterised

When Does Expanded Eligibility Translate into Increased Take-Up? An Examination of Parental Leave Policy in Luxembourg

This article aims to explore the role of eligibility for parental leave as a determinant of access and as an enabler of leave take-up. To analyse the link between eligibility and take-up, we study a unique policy change in Luxembourg’s parental leave scheme. The country’s 2016 parental leave reform relaxed the eligibility criteria to enable marginal part-time working parents to access the parental leave scheme for the first time. We focus on this change and examine to what extent relaxing the eligibility criteria translated into increased take-up by the marginal part-time working parents who became eligible. To quantify this transition, we analyse trends in and patterns of eligibility for the scheme in Luxembourg between 2009 and 2018 among first-time parents working full-time, part-time, or marginal part-time hours. We use a subsample of Luxembourg-resident, cohabiting, first-time parents (N = 6,254) drawn from the social security data. Our analysis shows that as eligibility is dependent on individual factors, it has similarities among mothers and fathers, whereas take-up is notably greater for mothers. After the reform, we observe that marginal part-time working mothers started taking parental leave, but up to 2018, the reform’s outreach to marginal part-time working fathers remained limited. We also find that foreign national parents are less likely to be eligible for parental leave and have lower take-up rates. Despite the gendered parental leave take-up behaviours in parallel with international evidence, marginal part-time working mothers’ positive response to the reform indicates progress towards strengthening women’s labour market attachment in Luxembourg

Power inside - applications and technologies for integrated power in microelectronics

The emergence of miniaturized and integrated Power Supply on Chip (PwrSoC) and Power Supply in Package (PwrSiP) platforms will be enabled by the application of thin-film, integrated magnetics on silicon. A process flow for, and the design of, a thin-film coupled-inductor, switching at 60MHz, is described. Based on the large signal characterization data, measured up to 100MHz, the efficiency of the inductor is calculated to be 91.7% for a power of 0.5W

Integrated microinductors on semiconductor substrates for power supply on chip (Invited)

Microinductors were fabricated using electrodeposition for integration on semiconductor substrates. The process was optimised through validated models developed to focus on efficiency and footprint. Lithographic processing was performed to microfabricate Cu coils over a magnetic core. A racetrack design was used to maximise the high frequency response, yielding high inductance density and low DC resistance. The magnetic core was subsequently closed using a magnetic thin film deposition over a dielectric deposited on the Cu coils. Homogeneous ferromagnetic alloy, Ni45Fe55 of uniform thickness over a high aspect-ratio 3D structure has been achieved. Ni45Fe55 was chosen for the fabrication of micromagnetic cores due to its relatively high saturation flux density (1.6 T), resistivity (48 mΩ cm) and anisotropy field (9.5 Oe). The rationale, design, microfabrication process and characterisation results are presented

Dietary Supplementation with Soluble Plantain Non-Starch Polysaccharides Inhibits Intestinal Invasion of Salmonella Typhimurium in the Chicken

Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1–99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5–10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64–81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75–90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis

Does childhood trauma predict poorer metacognitive abilities in people with first-episode psychosis?

Research suggests that people with first-episode psychosis (FEP) report more childhood traumas and have lower metacognitive abilities than non-clinical controls. Childhood trauma negatively affects metacognitive development in population studies, while the association remains largely unexplored in FEP populations. Metacognition refers to the identification of thoughts and feelings and the formation of complex ideas about oneself and others. This study hypothesized that childhood trauma would be associated with lower metacognitive abilities in people with FEP. In a representative sample of 92 persons with non-affective FEP, we assessed childhood trauma, metacognitive abilities and symptoms of psychosis. We used the Childhood Trauma Questionnaire (CTQ) and the Metacognitive Assessment Scale––Abbreviated which includes Self-reflectivity, Awareness of the Mind of the Other, Decentration and Mastery. Hierarchical regression analyses were performed with metacognitive domains as outcome variables and childhood traumas as independent variables, while controlling for age, gender, first-degree psychiatric illness and negative symptoms. We found few significant associations between the different types of childhood trauma and metacognitive domains, and they suggested childhood trauma are associated with better metacognitive abilities. Study limitations included the cross-sectional design and use of self-report measures. Future studies could preferably be prospective and include different measures of psychopathology and neuropsychology

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN