2,717 research outputs found
Fracture Risk in Relation to Serum 25-Hydroxyvitamin D and Physical Activity: Results from the EPIC-Norfolk Cohort Study.
Vitamin D deficiency and physical inactivity have been associated with bone loss and fractures, but their combined effect has scarcely been studied either in younger or older adults. Therefore, we aimed to assess the associations between physical activity, age and 25-hydroxyvitamin D (25(OH)D) status separately and in combination with the incidence of fracture risk in the EPIC-Norfolk cohort study. Baseline (1993-1998) self-reported physical activity and serum 25(OH)D concentrations at follow-up (1998-2000) were collected in 14,624 men and women (aged 42-82 y between 1998 and 2000). Fracture incidence was ascertained up to March 2015. Cox proportional hazard model was used to determine HRs of fractures by plasma 25(OH)D (90 nmol/L), age (65 y) and physical activity (inactive and active) categories, by follow-up time per 20 nmol/L increase in serum 25(OH)D and to explore age-25(OH)D and physical activity-25(OH)D interactions. The age-, sex-, and month-adjusted HRs (95% CIs) for all fractures (1183 fractures) by increasing vitamin D category were not significantly different. With additional adjustment for body mass index, smoking status, alcohol intake, supplement use and history of fractures, the fracture risk was 29% lower in those participants with 50 to 70 nmol/L compared with those in the lowest quintile (<30 nmol/L). Physical inactivity based on a single baseline assessment was not associated with fracture risk. Vitamin D status appeared inversely related to fractures in middle aged adults. In older adults, the relationship between vitamin D status and fracture risk was observed to be J-shaped. Clinical and public health practice in vitamin D supplementation could partially explain these findings, although definitive conclusions are difficult due to potential changes in exposure status over the long follow up period.This work was supported by Medical Research Council (MRC) - MKS/S16 (RG19715) / Sponsor Funding Ref: G9502233; Cancer Research UK (CRUK) - MKS/R07 (RG14230) / Sponsor Funding Ref: SP2024/0201; and Cancer Research UK (CRUK) - MKS/T21 (RG23772) / Sponsor Funding Ref: SP2024/0204. CJA received a Grant FPU13/00421 from the Government of Spain “Ministerio de Educación, Cultura y Deporte”
Phosphate removal from water using an iron oxide impregnated strong base anion exchange resin
Removing phosphate from water is important as it causes eutrophication, which in turn has a harmful effect on aquatic life, resulting in a reduction in biodiversity. On the other hand, recovery of phosphate from phosphorus containing wastewater is essential for developing an alternative source of phosphorus to overcome the global challenge of phosphorus scarcity. Phosphate removal from aqueous solutions was studied using an iron oxide impregnated strong base anion exchange resin, Purolite FerrIX A33E in batch and fixed-bed column experiments. Phosphate adsorption in the batch study satisfactorily fitted to the Langmuir isotherm with a maximum adsorption capacity of 48mgP/g. In the column study, increase in inlet phosphate concentration (5-30 mgP/L), and filtration velocity (2.5-10 m/h) resulted in faster breakthrough times and increase in breakthrough adsorption capacities. Increase in bed height (3-19 cm) also increased adsorption capacity but the breakthrough time was slower. The breakthrough data were reasonably well described using the empirical models of Bohart-Adams, Thomas, and Yoon-Nelson, except for high bed heights. Phosphate adsorbed was effectively desorbed using 1M NaOH and the adsorbent was regenerated after each of three adsorption/desorption cycles by maintaining the adsorption capacity at >90% of the original value. Greater than 99.5% of the desorbed P was recovered by precipitation using CaCl2. © 2013 The Korean Society of Industrial and Engineering Chemistry
Single donor ionization energies in a nanoscale CMOS channel
One consequence of the continued downwards scaling of transistors is the
reliance on only a few discrete atoms to dope the channel, and random
fluctuations of the number of these dopants is already a major issue in the
microelectonics industry. While single-dopant signatures have been observed at
low temperature, studying the impact of only one dopant up to room temperature
requires extremely small lengths. Here, we show that a single arsenic dopant
dramatically affects the off-state behavior of an advanced microelectronics
field effect transistor (FET) at room temperature. Furthermore, the ionization
energy of this dopant should be profoundly modified by the close proximity of
materials with a different dielectric constant than the host semiconductor. We
measure a strong enhancement, from 54meV to 108meV, of the ionization energy of
an arsenic atom located near the buried oxide. This enhancement is responsible
for the large current below threshold at room temperature and therefore
explains the large variability in these ultra-scaled transistors. The results
also suggest a path to incorporating quantum functionalities into silicon CMOS
devices through manipulation of single donor orbitals
Design of a pulse power supply unit for micro-ECM
Electrochemical micro-machining (μECM) requires a particular pulse power supply unit (PSU) to be developed in order to achieve desired machining performance. This paper summarises the development of a pulse PSU meeting the requirements of μECM. The pulse power supply provides tens of nanosecond pulse duration, positive and negative bias voltages and a polarity switching functionality. It fulfils the needs for tool preparation with reversed pulsed ECM on the machine. Moreover, the PSU is equipped with an ultrafast overcurrent protection which prevents the tool electrode from being damaged in case of short circuits. The developed pulse PSU was used to fabricate micro-tools out of 170 μm WC-Co alloy shafts via micro-electrochemical turning and drill deep holes via μECM in a disk made of 18NiCr6. The electrolyte used for both processes was a mixture of sulphuric acid and NaNO3 aqueous solutions.The research reported in this paper is supported by the European Commission within the project “Minimizing Defects in Micro-Manufacturing Applications (MIDEMMA)” (FP7-2011-NMP-ICT-FoF-285614
Design of an electrochemical micromachining machine
Electrochemical micromachining (μECM) is a non-conventional machining process based on the phenomenon of electrolysis. μECM became an attractive area of research due to the fact that this process does not create any defective layer after machining and that there is a growing demand for better surface integrity on different micro applications including microfluidics systems, stress-free drilled holes in automotive and aerospace manufacturing with complex shapes, etc. This work presents the design of a next generation μECM machine for the automotive, aerospace, medical and metrology sectors. It has three axes of motion (X, Y, Z) and a spindle allowing the tool-electrode to rotate during machining. The linear slides for each axis use air bearings with linear DC brushless motors and 2-nm resolution encoders for ultra precise motion. The control system is based on the Power PMAC motion controller from Delta Tau. The electrolyte tank is located at the rear of the machine and allows the electrolyte to be changed quickly. This machine features two process control algorithms: fuzzy logic control and adaptive feed rate. A self-developed pulse generator has been mounted and interfaced with the machine and a wire ECM grinding device has been added. The pulse generator has the possibility to reverse the pulse polarity for on-line tool fabrication.The research reported in this paper is supported by the European Commission within the project “Minimizing Defects in Micro-Manufacturing Applications (MIDEMMA)” (FP7-2011-NMPICT- FoF-285614)
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Contribution of cod liver oil-related nutrients (vitamins A, D, E and eicosapentaenoic acid and docosahexaenoic acid) to daily nutrient intake and their associations with plasma concentrations in the EPIC-Norfolk cohort.
BACKGROUND: Total nutrient intake (TNI) is intake from food and supplements. This provides an assessment of nutrient adequacy and the prevalence of excessive intake, as well as the response with respect to biomarkers. Cod liver oil (CLO) is the most frequently consumed supplement in the UK, containing nutrients that might have varying influences on health. We calculated TNI for vitamins A, D and E, as well as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and assessed associations with the respective blood concentrations. METHODS: Seven-day diet diaries and blood samples were taken from two subsets of the European Prospective Investigation into Cancer (EPIC-Norfolk) cohort (age range 39-79 years; n = 1400 for vitamin D; n = 6656 for remaining nutrients). TNI was calculated for the subgroups: nonsupplement users, those consuming the nutrient in supplement form and those consuming a supplement without this nutrient. RESULTS: CLO-related nutrients were supplemented by 15%-33%, which approximately doubled median intakes. Almost everyone in the supplement + vitamin A group reached the estimated average requirement; however, guideline levels were likely to be exceeded. Partial correlations between intake of vitamins A and D and biomarkers were low and modestly strengthened by the inclusion of supplement sources (correlation = 0.01-0.13). Correlations between biomarker and TNI of vitamin E and EPA+DHA were in the range 0.40-0.46; however, vitamin E exceeding food intake resulted in attenuated coefficients. Linear associations between food or TNI EPA+DHA and plasma were weak but consistent across subgroups. CONCLUSIONS: CLO-related nutrients contribute substantially to nutrient intake, with a risk of over-consumption. Apart from EPA+DHA, biomarker data suggest that CLO-related nutrients in supplements are not linearly associated with vitamin status.All authors report grants from Cancer Research UK and grants from the Medical Research Council (MRC) during the study.This is the final published manuscript, first published by Wiley in the Journal of Human Nutrition and Dietetics here: http://dx.doi.org/10.1111/jhn.1227
Room-temperature ferromagnetism in graphite driven by 2D networks of point defects
Ferromagnetism in carbon-based materials is appealing for both applications
and fundamental science purposes because carbon is a light and bio-compatible
material that contains only s and p electrons in contrast to traditional
ferromagnets based on 3d or 4f electrons. Here we demonstrate direct evidence
for ferromagnetic order locally at defect structures in highly oriented
pyrolytic graphite (HOPG) with magnetic force microscopy and in bulk
magnetization measurements at room temperature. Magnetic impurities have been
excluded as the origin of the magnetic signal after careful analysis supporting
an intrinsic magnetic behavior of carbon. The observed ferromagnetism has been
attributed to originate from unpaired electron spins localized at grain
boundaries of HOPG. Grain boundaries form two-dimensional arrays of point
defects, where their spacing depends on the mutual orientation of two grains.
Depending on the distance between these point defects, scanning tunneling
spectroscopy of grain boundaries showed two intense split localized states for
small distances between defects (< 4 nm) and one localized state at the Fermi
level for large distances between defects (> 4 nm).Comment: 19 pages, 5 figure
The views of older women towards mammographic screening: a qualitative and quantitative study
Purpose: Mammographic screening has improved breast cancer survival in the screened age group. This improved survival has not been seen in older women (>70 years) where screening uptake is low. This study explores the views, knowledge and attitudes of older women towards screening.
Methods: Women (>70) were interviewed about breast screening. Interview findings informed the development of a questionnaire which was sent to 1000 women (>70) to quantify their views regarding screening.
Results: Twenty-six women were interviewed and a questionnaire designed. The questionnaire response rate was 48.3% (479/992). Over half (52.9%, 241/456) of respondents were unaware they could request mammography by voluntary self-referral and were unaware of how to arrange this. Most (81.5% 383/470) had not attended breast screening since turning 70. Most (75.6%, 343/454) felt screening was beneficial and would attend if invited. Most, (90.1%, 412/457) felt screening should be offered to all women regardless of age or health.
Conclusions: There is a lack of knowledge about screening in older women. The majority felt that invitation to screening should be extended to the older age group regardless of age or health. The current under-utilised system of voluntary self referral is not supported by older women
Can screening and brief intervention lead to population-level reductions in alcohol-related harm?
A distinction is made between the clinical and public health justifications for screening and brief intervention (SBI) against hazardous and harmful alcohol consumption. Early claims for a public health benefit of SBI derived from research on general medical practitioners' (GPs') advice on smoking cessation, but these claims have not been realized, mainly because GPs have not incorporated SBI into their routine practice. A recent modeling exercise estimated that, if all GPs in England screened every patient at their next consultation, 96% of the general population would be screened over 10 years, with 70-79% of excessive drinkers receiving brief interventions (BI); assuming a 10% success rate, this would probably amount to a population-level effect of SBI. Thus, a public health benefit for SBI presupposes widespread screening; but recent government policy in England favors targeted versus universal screening, and in Scotland screening is based on new registrations and clinical presentation. A recent proposal for a national screening program was rejected by the UK National Health Service's National Screening Committee because 1) there was no good evidence that SBI led to reductions in mortality or morbidity, and 2) a safe, simple, precise, and validated screening test was not available. Even in countries like Sweden and Finland, where expensive national programs to disseminate SBI have been implemented, only a minority of the population has been asked about drinking during health-care visits, and a minority of excessive drinkers has been advised to cut down. Although there has been research on the relationship between treatment for alcohol problems and population-level effects, there has been no such research for SBI, nor have there been experimental investigations of its relationship with population-level measures of alcohol-related harm. These are strongly recommended. In this article, conditions that would allow a population-level effect of SBI to occur are reviewed, including their political acceptability. It is tentatively concluded that widespread dissemination of SBI, without the implementation of alcohol control measures, might have indirect influences on levels of consumption and harm but would be unlikely on its own to result in public health benefits. However, if and when alcohol control measures were introduced, SBI would still have an important role in the battle against alcohol-related harm
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