852 research outputs found
Can exercise limits prevent post-exertional malaise in chronic fatigue syndrome? An uncontrolled clinical trial.
<b>Objective</b>: It was hypothesized that the use of exercise limits prevents symptom increases and worsening of their health status following a walking exercise in people with Chronic Fatigue Syndrome (CFS).
<b>Design</b>: An uncontrolled clinical trial (semi-experimental design).
<b>Setting</b>: Outpatient clinic of a university department.
<b>Subjects</b>: 24 patients with CFS.
<b>Interventions</b>: Subjects undertook a walking test with the two concurrent exercise limits. Each subject walked at an <i>intensity</i> where the maximum heart rate was determined by heart rate corresponding to the respiratory exchange ratio =1.0 derived from a previous sub-maximal exercise test and for a duration calculated from how long each patient felt they were able to walk.
<b>Main outcome measures</b>: The Short Form 36 Health Survey or SF-36, the CFS Symptom List, and the CFS-Activities and Participation Questionnaire were filled in prior to, immediately and 24 hours post-exercise.
<b>Results</b>: The fatigue increase observed immediately post-exercise (p=0.006) returned to pre-exercise levels 24 hours post-exercise. The increase in pain observed immediately post-exercise was retained at 24 hours post-exercise (p=0.03). Fourteen of 24 subjects experienced a clinically meaningful change in bodily pain (change of SF-36 bodily pain score ³10). Six of 24 participants indicated that the exercise bout had slightly worsened their health status, and 2 of 24 had a clinically meaningful decrease in vitality (change of SF-36 vitality score ³20). There was no change in activity limitations/participation restrictions.
<b>Conclusion</b>: It was shown that the use of exercise limits (limiting both the intensity and duration of exercise) prevents important health status changes following a walking exercise in people with CFS, but was unable to prevent short-term symptom increases
Strategies for estimating human exposure to mycotoxins via food
In this review, five strategies to estimate mycotoxin exposure of a (sub-) population via food, including data collection, are discussed with the aim to identify the added values and limitations of each strategy for risk assessment of these chemicals. The well-established point estimate, observed individual mean, probabilistic and duplicate diet strategies are addressed, as well as the emerging human biomonitoring strategy. All five exposure assessment strategies allow the estimation of chronic (long-term) exposure to mycotoxins, and, with the exception of the observed individual mean strategy, also acute (short-term) exposure. Methods for data collection, i.e. food consumption surveys, food monitoring studies and total diet studies are discussed. In food monitoring studies, the driving force is often enforcement of legal limits, and, consequently, data are often generated with relatively high limits of quantification and targeted at products suspected to contain mycotoxin levels above these legal limits. Total diet studies provide a solid base for chronic exposure assessments since they provide mycotoxin levels in food based on well-defined samples and including the effect of food preparation. Duplicate diet studies and human biomonitoring studies reveal the actual exposure but often involve a restricted group of human volunteers and a limited time period. Human biomonitoring studies may also include exposure to mycotoxins from other sources than food, and exposure to modified mycotoxins that may not be detected with current analytical methods. Low limits of quantification are required for analytical methods applied for data collection to avoid large uncertainties in the exposure due to high numbers of left censored data, i.e. with levels below the limit of quantification
Public health aspects of Fusarium mycotoxins in food in The Netherlands : a risk assessment
Plant pathogenic Fusarium moulds occur world-wide and cereals can become infected during the growing period. Fusarium was detected in 83 % of 69 cereal samples of batches intended for food or feed production and harvested in The Netherlands in 1993. A considerable genotypic and phenotypic variation was observed within two of the most frequently isolated Fusarium species. Mycotoxins can be excreted in the crop by the fungus after the plant becomes infected. A literature review revealed 137 secondary metabolites that could be, produced by Fusarium species which were isolated from food raw materials. Twelve of those secondary metabolites were identified as mycotoxins based on toxicity observed in test animals. Six of those twelve have possibly been involved in human disease outbreaks (T-2 toxin, nivalenol, deoxynivalenol, acetyldeoxynivalenol, fumonisin B1 and zearalenone). Most of the mycotoxins are stable under process conditions used for food production and can be detected in food. Cereals harvested in The Netherlands in 1993 were contaminated with deoxynivalenol (food poisoning and immunotoxic), 3 %, or zearalenone (oestrogen), 1 %. Fumonisin B 1 (carcinogenic, related to human oesophageal cancer) was detected in 98 % of samples of maize from batches imported in The Netherlands and intended for food production. A 28-day toxicity study on the effects of fumonisin B 1 in rats revealed dose-response related apoptosis in the kidney. The lowest observed effect level was at 0.19 mg fumonisin B 1 kg -1rat body weight. The data on fumonisin B 1 toxicity were used to estimate a tolerable daily intake (TDI) of 500 ng fumonisin B 1 kg -1human body weight. The probability of being daily exposed to fumonisin B 1 at a level corresponding to this TDI was 12 % for the people in The Netherlands consuming the average amount of maize, 55 % for people belonging to the group of 'eaters only' and 78 % for people with gluten intolerance. The health of the consumers in The Netherlands might, in the current situation, be challenged by Fusarium mycotoxins present in food. Deoxynivalenol, which has immunotoxic characteristics, can potentially be present in food and feed and might increase human exposure to infectious diseases, especially to those from zoonotic origin
Temperament and character in men with autism spectrum disorder: A reanalysis of scores on the Temperament and Character Inventory by individual case matching
Non-destructive characterization of nitrogen-implanted silicon-on-insulator structures by spectroscopic ellipsometry
Silicon-on-insulator (SOI) structures implanted with 200 or 400 keV N+ ions at a dose of 7.5 × 1017cm−2 were studied by spectroscopic ellipsometry (SE). The SE measurements were carried out in the 300–700 nm wavelength (4.13-1.78 eV photon energy) range. The SE data were analysed by the conventional method of using appropriate optical models and linear regression analysis. We applied a seven-layer model (a surface oxide layer, a thick silicon layer, upper two interface layers, a thick nitride layer and lower two interface layers) with good results. The fitted parameters were the layer thickness and compositions. The results were compared with data obtained from Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy. The sensitivity of our optical model and fitting technique was good enough to distinguish between the silicon-rich transition layers near the upper and lower interfaces of the nitride layer, which are unresolvable in RBS measurements
Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach
There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox – a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale
Fast particle-mesh code for Milgromian dynamics
Modified Newtonian dynamics (MOND) is a promising alternative to dark matter.
To further test the theory, there is a need for fluid- and particle-dynamics
simulations. The force in MOND is not a direct particle-particle interaction,
but derives from a potential for which a nonlinear partial differential
equation (PDE) needs to be solved. Normally, this makes the problem of
simulating dynamical evolution computationally expensive. We intend to develop
a fast particle-mesh (PM) code for MOND (the AQUAL formalism). We transformed
the nonlinear equation for MOND into a system of linear PDEs plus one algebraic
equation. An iterative scheme with the fast Fourier transform (FFT) produces
successively better numerical approximations. The algorithm was tested for
dynamical systems in MOND where analytical solutions are known: the two-body
problem, a body with a circular ring, and a spherical distribution of particles
in thermal equilibrium in the self-consistent potential. The PM code can
accurately calculate the forces at subpixel scale and reproduces the analytical
solutions. Four iterations are required for the potential, but when the spatial
steps are small compared to the kernel width, one iteration is suffices. The
use of a smoothing kernel for the accelerations is inevitable in order to
eliminate the self-gravity of the point particles. Our PDE solver is to
times as slow as a standard Poisson solver. However, the smoothing and
particle propagation takes up most of the time above one particle per
pixels. The FFTs, the smoothing, and the propagation part in the code can all
be parallelized.Comment: 13 pages, 13 figure
Vicinal Surfaces and the Calogero-Sutherland Model
A miscut (vicinal) crystal surface can be regarded as an array of meandering
but non-crossing steps. Interactions between the steps are shown to induce a
faceting transition of the surface between a homogeneous Luttinger liquid state
and a low-temperature regime consisting of local step clusters in coexistence
with ideal facets. This morphological transition is governed by a hitherto
neglected critical line of the well-known Calogero-Sutherland model. Its exact
solution yields expressions for measurable quantities that compare favorably
with recent experiments on Si surfaces.Comment: 4 pages, revtex, 2 figures (.eps
Eliminating irreproducibility in SERS substrates
Irreproducibility in surface-enhanced Raman spectroscopy (SERS) due to variability among substrates is a source of recurrent debate within the field. It is regarded as a major hurdle towards the widespread adoption of SERS as a sensing platform. Most of the literature focused on developing substrates for various applications considers reproducibility of lower importance. Here, we address and analyse the sources of this irreproducibility in order to show how these can be minimised. We apply our findings to a simple substrate demonstrating reproducible SERS measurements with relative standard deviations well below 1% between different batches and days. Identifying the sources of irreproducibility and understanding how to reduce these can aid in the transition of SERS from the lab to real world applications.Isaac Newton Trust
Leverhulme Trust
Winton Programme for the Physics of Sustainability
Trinity College, University of Cambridg
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