2,881 research outputs found

    A simple ZVI-Fenton pre-oxidation using steel-nails for NOM degradation in water treatment

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    The feasibility of a heterogeneous Fenton Process (ZVI/H2O2) using commercial low-carbon-steel nails as the Zero-Valent Iron (ZVI) source was evaluated for the first time for the removal of natural organic matter (NOM) from natural surface waters with distinct physico-chemical characteristics. The synergistic effect of ZVI nails and H2O2 on the process was confirmed. Results showed similar removal efficiencies of NOM in water samples from Thames river and Regent's Park lake (both in London, UK) (under initial pH 3.5 and 100% excess of H2O2 dosage), reaching dissolved organic carbon (DOC) removals of 61.6% ± 3.0 and 59.6% ± 4.7, and UV254 removals of 79.9% ± 0.6 and 77.3 ± 6.2, respectively with 60 min of batch reaction time. ZVI nail surface characterization by scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), and X-ray photoemission spectroscopy (XPS) revealed the formation of a passivating oxide-hydroxide layer on the nail during the reaction, which reduces its surface activity with 20% in continuous use. Results indicate that ZVI/H2O2 process using commercial iron nails is a promising pre-oxidation step for drinking water treatment. The low cost of commercial nails together with the facility of separating them from the water are the main advantages for the application of this process in remote regions with limitations in infrastructure and/or finance

    Echocardiographic evaluation including tissue Doppler imaging in New Zealand white rabbits sedated with ketamine and midazolam

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    Limited data are available on the use of more recent echocardiographic parameters in the rabbit. Echocardiographic examination, including conventional echocardiography and tissue Doppler imaging (TDI), was performed on 26 male New Zealand white rabbits under ketamine-midazolam sedation. Particular emphasis was placed on the more recent systolic and diastolic parameters, such as myocardial performance index (Tei index) and mitral annular motion (from septal and lateral sides of the left ventricle) obtained using pulsed TDI. Parameters that assessed systolic and diastolic function (fractional shortening, Tei index, and maximal mitral E- and A-wave velocities) were comparable to those reported in the literature for rabbits in the awake state. The less cardiodepressive anaesthetic protocol could offer a good alternative in performing echocardiographic evaluation whenever such caution is necessary. TDI is feasible in healthy rabbits and potentially suitable for the investigation of left ventricle systolic and diastolic function

    A randomised controlled trial of a code-word enuresis alarm

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    Objective: To compare a novel code-word alarm with a commercially available wireless alarm for treating enuresis Design: Randomised controlled trial with blinding of study personnel and outcome assessors Setting: A tertiary paediatric centre Patients: Children aged six to eighteen with at least three wet nights per week in the previous 6 months referred by doctors Outcomes: Primary outcome: the proportion who achieved a full response (14 consecutive dry nights) by 16 weeks. Secondary outcomes: change in frequency of wetting, duration of alarm training, percentage of wet nights that the child woke to the alarm, adherence to treatment, adverse events and satisfaction with treatment. Results: Of the 353 participants, 176 were assigned to the code-word alarm and 177 to control. At 16 weeks, 54% (95% CI, 47% to 61%) in the experimental group and 47% (95% CI, 40% to 55%) in the control group had achieved a full response (p=0.22), with 74% and 66% respectively attaining a 50% or more reduction in wetting frequency (p=0.14). The experimental group woke more often than the control group (median percentage of waking 88% versus 77%, p=0.003) and had greater reduction in wet nights (median reduction 10 versus 9 nights per fortnight). Fewer in the experimental group discontinued therapy before achieving a full response (27% versus 37% discontinued, p=0.04). There were no significant differences in relapse rates at 6 months, adverse events or satisfaction between the two alarms. In a post hoc subgroup analysis of children with monosymptomatic enuresis, more in the experimental group achieved a full response (66% versus 52%, p=0.047), with higher median percentage of waking (89% versus 79%, p=0.006) and greater reduction in wet nights (median reduction 12 versus 9 nights per fortnight). Conclusions: Although the code-word alarm increased waking, no difference in full response rates was demonstrated between the two alarms.The study was funded by an NHMRC Project Grant (570761). AT was supported by an NHMRC Program Grant (633003) to the Screening & Test Evaluation Program

    Coupling interactive fire with atmospheric composition and climate in the UK Earth System Model

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    Fire constitutes a key process in the Earth system (ES), being driven by climate as well as affecting the climate by changing atmospheric composition and impacting the terrestrial carbon cycle. However, studies on the effects of fires on atmospheric composition, radiative forcing and climate have been limited to date, as the current generation of ES models (ESMs) does not include fully atmosphere–composition–vegetation coupled fires feedbacks. The aim of this work is to develop and evaluate a fully coupled fire–composition–climate ES model. For this, the INteractive Fires and Emissions algoRithm for Natural envirOnments (INFERNO) fire model is coupled to the atmosphere-only configuration of the UK's Earth System Model (UKESM1). This fire–atmosphere interaction through atmospheric chemistry and aerosols allows for fire emissions to influence radiation, clouds and generally weather, which can consequently influence the meteorological drivers of fire. Additionally, INFERNO is updated based on recent developments in the literature to improve the representation of human and/or economic factors in the anthropogenic ignition and suppression of fire. This work presents an assessment of the effects of interactive fire coupling on atmospheric composition and climate compared to the standard UKESM1 configuration that uses prescribed fire emissions. Results show a similar performance when using the fire–atmosphere coupling (the “online” version of the model) when compared to the offline UKESM1 that uses prescribed fire. The model can reproduce observed present-day global fire emissions of carbon monoxide (CO) and aerosols, despite underestimating the global average burnt area. However, at a regional scale, there is an overestimation of fire emissions over Africa due to the misrepresentation of the underlying vegetation types and an underestimation over equatorial Asia due to a lack of representation of peat fires. Despite this, comparing model results with observations of CO column mixing ratio and aerosol optical depth (AOD) show that the fire–atmosphere coupled configuration has a similar performance when compared to UKESM1. In fact, including the interactive biomass burning emissions improves the interannual CO atmospheric column variability and consequently its seasonality over the main biomass burning regions – Africa and South America. Similarly, for aerosols, the AOD results broadly agree with the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Aerosol Robotic Network (AERONET) observations

    Identifying critically important vascular access outcomes for trials in haemodialysis : an international survey with patients, caregivers and health professionals

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    BACKGROUND: Vascular access outcomes reported across haemodialysis (HD) trials are numerous, heterogeneous and not always relevant to patients and clinicians. This study aimed to identify critically important vascular access outcomes. METHOD: Outcomes derived from a systematic review, multi-disciplinary expert panel and patient input were included in a multilanguage online survey. Participants rated the absolute importance of outcomes using a 9-point Likert scale (7-9 being critically important). The relative importance was determined by a best-worst scale using multinomial logistic regression. Open text responses were analysed thematically. RESULTS: The survey was completed by 873 participants [224 (26%) patients/caregivers and 649 (74%) health professionals] from 58 countries. Vascular access function was considered the most important outcome (mean score 7.8 for patients and caregivers/8.5 for health professionals, with 85%/95% rating it critically important, and top ranked on best-worst scale), followed by infection (mean 7.4/8.2, 79%/92% rating it critically important, second rank on best-worst scale). Health professionals rated all outcomes of equal or higher importance than patients/caregivers, except for aneurysms. We identified six themes: necessity for HD, applicability across vascular access types, frequency and severity of debilitation, minimizing the risk of hospitalization and death, optimizing technical competence and adherence to best practice and direct impact on appearance and lifestyle. CONCLUSIONS: Vascular access function was the most critically important outcome among patients/caregivers and health professionals. Consistent reporting of this outcome across trials in HD will strengthen their value in supporting vascular access practice and shared decision making in patients requiring HD

    Longer duration of obesity is associated with a reduction in urinary angiotensinogen in prepubertal children

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    Background: We aimed to study the impact of obesity on urinary excretion of angiotensinogen (U-AGT) in prepubertal children, focusing on the duration of obesity and gender. Also, we aimed to evaluate whether plasma angiotensinogen (P-AGT) and hydrogen peroxide (H2O2) play a role in the putative association. Methods: Cross-sectional evaluation of 305 children aged 8–9 years (160 normal weight, 86 overweight, and 59 obese). Anthropometric measurements and 24-h ambulatory blood pressure monitoring were performed. Angiotensinogen (AGT) was determined by a commercial enzyme-linked immunosorbent assay (ELISA) kit and H2O2 by a microplate fluorometric assay. Results: U-AGT and P-AGT levels were similar across body mass index (BMI) groups and between sexes. However, boys who were overweight/obese since the age of 4 years presented lower levels of U-AGT compared with those of normal weight at the same age. In children who were overweight/obese since the age of 4, urinary H2O2 decreased with P-AGT. Conclusions: A higher duration of obesity was associated with decreased U-AGT in boys, thus reflecting decreased intrarenal activity of the renin–angiotensin system. Also, children with a longer duration of obesity showed an inverse association between urinary H2O2 and P-AGT. Future studies should address whether these results reflect an early compensatory mechanism to limit obesity-triggered renal dysfunction.This project was supported by funds from Fundo Europeu de Desenvolvimento Regional (FEDER) from Programa Operacional Factores de Competitividade – COMPETE (FCOMP-01-0124-FEDER-028751), by national funds from the Portuguese Foundation for Science and Technology (FCT) (PTDC/DTP-PIC/0239/2012) and by Calouste Gulbenkian Foundation, that granted the study design and data collection and analysis. Liane Correia-Costa was supported by FCT (grant SFRH/SINTD/95898/2013), Teresa Sousa was supported by FCT and POPH/FSE (EC) (Ciência 2008 and SFRH/BPD/112005) and Franz Schaefer was supported by the ERA-EDTA Research Programme and the KfH Foundation for Preventive Medicine. The Epidemiology Research Unit (EPIUnit) is funded by FCT (UID/DTP/04750/2013)

    Impact of physical activity on redox status and nitric oxide bioavailability in nonoverweight and overweight/obese prepubertal children

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    Nutritional status might contribute to variations induced by physical activity (PA) in redox status biomarkers. We investigated the influence of PA on redox status and nitric oxide (NO) production/metabolism biomarkers in nonoverweight and overweight/obese prepubertal children. We performed a cross-sectional evaluation of 313 children aged 8-9 years (163 nonoverweight, 150 overweight/obese) followed since birth in a cohort study (Generation XXI, Porto, Portugal). Plasma total antioxidant status (P-TAS), plasma and urinary isoprostanes (P-Isop, U-Isop), urinary hydrogen peroxide (U-H2O2), myeloperoxidase (MPO) and plasma and urinary nitrates and nitrites (P-NOx, U-NOx) were assessed, as well as their association with variables of reported PA quantification (categories of PA frequency (>1x/week and ≤1x/week)and continuous PA index (obtained by the sum of points)) in a questionnaire with increasing ranks from sedentary to vigorous activity levels. U-NOx was significantly higher in children who presented higher PA index scores and higher PA frequency. Separately by BMI classes, U-NOx was significantly higher only in nonoverweight children who practiced PA more frequently (p = 0.037). In overweight/obese children, but not in nonoverweight, P-TAS was higher among children with higher PA frequency (p = 0.007). Homeostasis model assessment index (HOMA-IR) was significantly lower in more active overweight/obese children, but no differences were observed in nonoverweight children. In the fully adjusted multivariate linear regression models for P-TAS, in the overweight/obese group, children with higher PA frequency presented higher P-TAS. In the U-NOx models, U-NOx significantly increased with PA index, only in nonoverweight children. Our results provide additional evidence in support of a protective effect of physical activity, in nonoverweight by increasing NO bioavailability and in overweight/obese children by enhancing systemic antioxidant capacity and insulin sensitivity. These results highlight the importance of engaging in regular physical exercise, particularly among overweight/obese children, in which a positive association between oxidant status and cardiometabolic risk markers has been described.This project was supported by FEDER funds from Programa Operacional Factores de Competitividade – COMPETE [FCOMP-01-0124-FEDER-028751], by national funds from the Portuguese Foundation for Science and Technology (FCT), Lisbon, Portugal [PTDC/DTP-PIC/0239/2012] and by Calouste Gulbenkian Foundation. Liane Correia-Costa was supported by FCT [SFRH/SINTD/95898/2013] and Teresa Sousa was supported by FCT and POPH/FSE (EC) [Ciência 2008 and SFRH/BPD/112005]

    Being a Young Carer in Portugal: The Impact of Caring on Adolescents' Life Satisfaction

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    Caring for an ill or disabled relative can present significant challenges that may exceed the personal resources of the caregiver. Young carers (YCs) often take on this role, providing support to family members or friends, which can have far-reaching effects on various aspects of their lives. This study involved 235 adolescents, 106 YCs, and 129 non-carers (NCs), who completed questionnaires assessing life satisfaction, satisfaction with social support, family functioning, academic functioning, and caregiving activities. Tests of group differences (MANOVA and MANCOVA controlling for age) showed YCs had more caregiving activities than NCs (as expected) and, critically, significantly lower life satisfaction. Hierarchical regressions with the YCS subsample showed academic functioning, social support, and the negative impact of caregiving were associated with life satisfaction, and that the negative influence of caregiving was linked to family functioning and the quantity of caregiving activities. For NCs, academic functioning, satisfaction with social support, and family functioning were associated with life satisfaction. In conclusion, caregiving in adolescents appears to be linked to lower life satisfaction, but this effect is determined by their social support, academic functioning, and negative impact of caring, which in turn depends on their family functioning and amount of caring activities
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