197 research outputs found
Peltier Effect Applied to the Design and Realization of a New Mass Flow Sensor
The present paper deals with design and realization of a new mass flow sensor using the
Peltier effect. The sensor, shaped as a bimetallic circuit includes two continuous parallel
strips coated with a great deal of metal plated spots. In such a device, one track performs
as a classical thermoelectrical circuitry whose both plated and uncoated parts provide
the thermopile junctions. The other strip is subjected to electrical current so as to generate
numerous small thermal gradients owing to the Peltier effect. Then, the resulting
differences in temperature induce a Seebeck e.m.f. detected by the other strip acting
as a receiver. The thermal coupling between transmitter and receiver tracks depends on
many variation of the surrounding environment heat transfer coefficient. Therefore,
such a device allows us to detect any shift in physical properties related to the apparent
thermal conductivity. In special case of a steady state fluid, the induced e.m.f. in the
receiving track hinges on the thermal conductivity. When the fluid is in relative motion
along the sensor, the velocity can be read out as a funotion of voltage as an application,
the sensor is placed into a tube conducting a fluid flow, in order to design a new mass
flowmeter
Indoor Particulate Matter Concentration, Water Boiling Time, and Fuel Use of Selected Alternative Cookstoves in a Home-Like Setting in Rural Nepal
Alternative cookstoves are designed to improve biomass fuel combustion efficiency to reduce the amount of fuel used and lower emission of air pollutants. The Nepal Cookstove Trial (NCT) studies effects of alternative cookstoves on family health. Our study measured indoor particulate matter concentration (PM2.5), boiling time, and fuel use of cookstoves during a water-boiling test in a house-like setting in rural Nepal. Study I was designed to select a stove to be used in the NCT; Study II evaluated stoves used in the NCT. In Study I, mean indoor PM2.5 using wood fuel was 4584 μg/m3 , 1657 μg/m3 , and 2414 μg/m3 for the traditional, alternative mud brick stove (AMBS-I) and Envirofit G-series, respectively. The AMBS-I reduced PM2.5 concentration but increased boiling time compared to the traditional stove (p-values \u3c 0.001). Unlike AMBS-I, Envirofit G-series did not significantly increase overall fuel consumption. In Phase II, the manufacturer altered Envirofit stove (MAES) and Nepal Nutrition Intervention Project Sarlahi (NNIPS) altered Envirofit stove (NAES), produced lower mean PM2.5, 1573 μg/m3 and 1341 μg/m3 , respectively, relative to AMBS-II 3488 μg/m3 for wood tests. The liquid propane gas stove had the lowest mean PM2.5 concentrations, with measurements indistinguishable from background levels. Results from Study I and II showed significant reduction in PM2.5 for all alternative stoves in a controlled setting. In study I, the AMBS-I stove required more fuel than the traditional stove. In contrast, in study II, the MAES and NAES stoves required statistically less fuel than the AMBS-II. Reductions and increases in fuel use should be interpreted with caution because the composition of fuels was not standardized—an issue which may have implications for generalizability of other findings as well. Boiling times for alternative stoves in Study I were significantly longer than the traditional stove—a trade-off that may have implications for acceptability of the stoves among end users. These extended cooking times may increase cumulative exposure during cooking events where emission rates are lower; these differences must be carefully considered in the evaluation of alternative stove designs
Dissecting Fc signatures of protection in neonates following maternal influenza vaccination in a placebo-controlled trial.
Influenza is an important cause of illness and morbidity for infants. Seasonal influenza vaccination during pregnancy aims to provide protection to mothers, but it can also provide immunity to infants. The precise influence of maternal vaccination on immunity in infants and how vaccine-elicited antibodies provide protection in some but not all infants is incompletely understood. We comprehensively profiled the transfer of functional antibodies and defined humoral factors contributing to immunity against influenza in a clinical trial of maternal influenza vaccination. Influenza-specific antibody subclass levels, Fc ɣ receptor (FCGR) binding levels, and antibody-dependent innate immune functions were all profiled in the mothers during pregnancy and at birth, as well as in cord blood. Vaccination increased influenza-specific antibody levels, antibody binding to FCGR, and specific antibody-dependent innate immune functions in both maternal and cord blood, with FCGR binding most enhanced via vaccination. Influenza-specific FCGR binding levels were lower in cord blood of infants who subsequently developed influenza infection. Collectively these data suggest that in addition to increased antibody amounts, the selective transfer of FCGR-binding antibodies contributes to the protective immune response in infants against influenza
Randomized, double blind study of non-excitatory, cardiac contractility modulation electrical impulses fr symptomatic heart failure
AIMS: We performed a randomized, double blind, crossover study of cardiac contractility modulation (CCM) signals in heart failure patients.
METHODS AND RESULTS: One hundred and sixty-four subjects with ejection fraction (EF) < 35% and NYHA Class II (24%) or III (76%) symptoms received a CCM pulse generator. Patients were randomly assigned to Group 1 (n = 80, CCM treatment 3 months, sham treatment second 3 months) or Group 2 (n = 84, sham treatment 3 months, CCM treatment second 3 months). The co-primary endpoints were changes in peak oxygen consumption (VO2,peak) and Minnesota Living with Heart Failure Questionnaire (MLWHFQ). Baseline EF (29.3 +/- 6.7% vs. 29.8 +/- 7.8%), VO2,peak (14.1 +/- 3.0 vs. 13.6 +/- 2.7 mL/kg/min), and MLWHFQ (38.9 +/- 27.4 vs. 36.5 +/- 27.1) were similar between the groups. VO2,peak increased similarly in both groups during the first 3 months (0.40 +/- 3.0 vs. 0.37 +/- 3.3 mL/kg/min, placebo effect). During the next 3 months, VO2,peak decreased in the group switched to sham (-0.86 +/- 3.06 mL/kg/min) and increased in patients switched to active treatment (0.16 +/- 2.50 mL/kg/min). MLWHFQ trended better with treatment (-12.06 +/- 15.33 vs. -9.70 +/- 16.71) during the first 3 months, increased during the second 3 months in the group switched to sham (+4.70 +/- 16.57), and decreased further in patients switched to active treatment (-0.70 +/- 15.13). A comparison of values at the end of active treatment periods vs. end of sham treatment periods indicates statistically significantly improved VO2,peak and MLWHFQ (P = 0.03 for each parameter).
CONCLUSION: In patients with heart failure and left ventricular dysfunction, CCM signals appear safe; exercise tolerance and quality of life (MLWHFQ) were significantly better while patients were receiving active treatment with CCM for a 3-month period
Variability in the contents of pork meat nutrients and how it may affect food composition databases
Pork meat is generally recognised as a food with relevant nutritional properties because of its content in high biological value proteins, group B vitamins, minerals especially heme iron, trace elements and other bioactive compounds. But pork meat also contributes to the intake of fat, saturated fatty acids, cholesterol, and other substances that, in inappropriate amounts, may result in negative physiologically effects. However, there are relevant factors affecting the content of many of these substances and somehow such variability should be taken into consideration. So, genetics, age and even type of muscle have a relevant influence on the amount of fat and the contents in heme iron. Also the composition in fatty acids of triacylglycerols is very sensitive to the contents of cereals in the feed; for instance, polyunsaturated fatty acids may range from 10% to 22% in pork meat. The content of other nutrients, like vitamins E and A, are also depending on the type of feed. Some bioactive substances like coenzyme Q10, taurine, glutamine, creatine, creatinine, carnosine and anserine show a large dependence on the type of muscle. This manuscript describes the main factors affecting the composition of pork meat nutrients and how these changes may affect the general food composition databases. (C) 2012 Elsevier Ltd. All rights reserved.Grant AGL2010-16305 from the Spanish Ministry of Science and Innovation (Madrid, Spain) and FEDER Funds and collaboration of Vaquero Foundation for R+D on Pork Meat (Madrid, Spain) are acknowledged. Grant PROMETEO/2012/001 from Generalitat Valenciana (Spain) is also acknowldeged. Work prepared within the Unidad Asociada IAD (UPV)-IATA (CSIC) framework.Reig Riera, MM.; Aristoy, M.; Toldra, F. (2013). Variability in the contents of pork meat nutrients and how it may affect food composition databases. Food Chemistry. 140(3):478-482. https://doi.org/10.1016/j.foodchem.2012.11.085S478482140
Inflammation and insulin resistance according to body composition in European adolescents: the HELENA study
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Open access journalIntroduction: Inflammation is related to insulin resistance in adults, especially on those individuals with high levels of body composition.
Objectives: The aim of this study is to assess the relationship between a set of inflammatory biomarkers and insulin resistance by levels of body composition in a sample of European adolescents.
Material and methods: 962 adolescents (442 boys and 520 girls) from 9 European countries met the inclusion criteria of having measurements for the homeostasis model assessment (HOMA) and a set of inflammation-related biomarkers: C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin (IL-6), complement factors C3 and C4 and selected cell adhesion molecules. Body mass index (BMI), fat mass index (FMI) and waist circumference (WC) were categorized using tertiles. To assess the associations stratifying by body composition indexes, ANOVA and linear regression models were performed
Results: Mean biomarkers’ concentrations differed across BMI, FMI and WC tertiles (p<0.05), by sex. In both sexes, insulin, HOMA, CRP, C3 and C4 were significantly different between categories (p<0.001), always showing the highest mean concentration in the upper category of BMI, FMI and WC. The most consistent finding was an association between insulin resistance and C3 concentrations (p<0.05), in the adolescents in the highest tertile of BMI, FMI and WC, except in the case of FMI in girls.
Conclusion: Inflammatory and glucose metabolism markers differed by tertiles of body composition, being usually higher in the highest tertile. C3 complement factor was associated with insulin resistance in adolescents, especially those with high total and abdominal adiposity
Relationship between self-reported dietary intake and physical activity levels among adolescents: The HELENA study
Background
Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. Therefore it is important to investigate associations between dietary and physical activity behavior, the two most important lifestyle behaviors influencing our energy balance and body composition. The objective of the present study is to describe the relationship between energy, nutrient and food intake and the physical activity level among a large group of European adolescents.
Methods
The study comprised a total of 2176 adolescents (46.2% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Dietary intake and physical activity were assessed using validated 24-h dietary recalls and self-reported questionnaires respectively. Analyses of covariance (ANCOVA) were used to compare the energy and nutrient intake and the food consumption between groups of adolescents with different physical activity levels (1st to 3rd tertile).
Results
In both sexes no differences were found in energy intake between the levels of physical activity. The most active males showed a higher intake of polysaccharides, protein, water and vitamin C and a lower intake of saccharides compared to less active males. Females with the highest physical activity level consumed more polysaccharides compared to their least active peers. Male and female adolescents with the highest physical activity levels, consumed more fruit and milk products and less cheese compared to the least active adolescents. The most active males showed higher intakes of vegetables and meat, fish, eggs, meat substitutes and vegetarian products compared to the least active ones. The least active males reported the highest consumption of grain products and potatoes. Within the female group, significantly lower intakes of bread and cereal products and spreads were found for those reporting to spend most time in moderate to vigorous physical activity. The consumption of foods from the remaining food groups, did not differ between the physical activity levels in both sexes.
Conclusion
It can be concluded that dietary habits diverge between adolescents with different self-reported physical activity levels. For some food groups a difference in intake could be found, which were reflected in differences in some nutrient intakes. It can also be concluded that physically active adolescents are not always inclined to eat healthier diets than their less active peers.The HELENA study took place with the financial support of the European Community Sixth RTD Framework Programme (Contract FOOD-CT: 2005-007034). This work was also partially supported by the European Union, in the framework of the Public Health Programme (ALPHA project, Ref: 2006120), the Swedish Council for Working Life and Social Research (FAS), the Spanish Ministry of Education (EX-2007-1124, and EX-2008-0641), and the Spanish Ministry of Health, Maternal, Child Health and Development Network (number RD08/0072) (JPRL, LAM)
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