6,443 research outputs found
Heat transfer with phase change in a shell and tube latent heat storage unit
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Concerning thermal energy storage, latent heat thermal energy storage is particularly attractive technique because it provides a high energy storage density. The development of a latent heat thermal energy storage system therefore involves first the understanding of heat transfer in the phase change materials (PCM) when they undergo solid-to-liquid phase transition in the required operating temperature range, and second, the design of the container for holding the PCM and the formulation of the phase change problem.
The paper presents a study on the heat transfer mode of a PCM stored in a horizontal cylindrical shell and tube heat exchanger, being the PCM placed inside the tubes. For this purpose, an experimental bench has been developed to test the heat transfer process, coupled with a Ground-Source Heat Pump (GSHP), controlled by a computer program developed to manage the coupled GSHP+PCM system. The aim is to compute the heat transfer of the installation during the loading, storage and downloading energy processes. More precisely, the interest is to check experimentally to what extent some common hypothesis used for heat transfer calculations are valid or not. In particular: (i) Comparison between the radial and the axial heat transfer through the wall of the PCM tube; (ii) The temperature distribution of the heat transfer fluid in the central and peripheral locations; (iii) The heat transfer rate between the container and the ambient temperature. Results indicate that density gradients could occur during energy exchange between the heat transfer fluid and the PCM when melting or solidification are taking place, leading to modification of central flow with respect to peripheral flow. Also, the temperature gradients recorded in the axial direction during the change of phase were very small compared with those of that of the radial direction, indicating essentially a two-dimensional heat transfer mode.dc201
PREDICTION OF MORTALITY OF APACHE-II AND APACHE-III SCORES IN PATIENTS ADMITTED TO THE INTENSIVE CARE UNIT (ICU) FOR INTOXICATION
Large Nc QCD and Harmonic Sums
In the Large-Nc limit of QCD, two--point functions of local operators become
Harmonic Sums. I review some properties which follow from this fact and which
are relevant for phenomenological applications. This has led us to consider a
class of Analytic Number Theory Functions as toy models of Large-Nc QCD which I
also discuss.Comment: Based on my talk at "Raymond Stora's 80th Birthday Party", LAPP, July
11th 201
RELATION BETWEEN MORTALITY FOR FOUR YEARS AND COMPUTERIZED TOMOGRAPHY BY MARSHALL SCORE IN TRAUMATIC BRAIN INJURY CRITICAL PATIENTS
Functional MMP-10 is required for efficient tissue repair after experimental hind limb ischemia
Polymorphisms associated with the number of live-born piglets in sows infected with the PRRS virus in southern Sonora Mexico
The porcine reproductive and respiratory syndrome (PRRS) is a viral disease that decreases the reproductive performance in breeding sows and leads to economic losses to the swine industry. The objective of the present study was to identify single nucleotide polymorphisms (SNP) associated to the number of live-born piglets in the first (LBP1) and second birth (LBP2) in breeding sows exposed to PRRS virus. The study included 100 pregnant females of the Landrace(¾)/ Yorkshire(¼) line, 75 of which were infected with the PRRS virus and 25 were free of PRRS. Individual blood samples (6-8 drops) were obtained and spotted onto FTA cards and subsequently processed for DNA extraction, which was genotyped using a 10,000 SNP chip for genomic profile. Resulting genotypes were analyzed using a multi-locus mixed model that detected three SNP associated to LBP1 and five SNP associated to LBP2 (P<0.001). These eight SNP were validated using an associative mixed effects model which included the terms genotype and age of dam as fixed effects, and sire as random effect. Allele substitution effects were estimated using the same model including the term genotype as covariate. The SNP rs81276080, rs81334603 and rs80947173 were associated to LBP1 (P<0.001), whereas the SNP rs81364943, rs80859829, rs80895640, rs80893794 and rs81245908 were associated to LBP2 (P<0.001). Only two SNP were in functional chromosomal regions and the remainder SNP were within an intergenic position. In conclusion, these results suggest the existence of gene variants associated with the reproductive performance of sows infected with the PRRS virus.The porcine reproductive and respiratory syndrome (PRRS) is a viral disease that decreases the reproductive performance in breeding sows and leads to economic losses to the swine industry. The objective of the present study was to identify single nucleotide polymorphisms (SNP) associated to the number of live-born piglets in the first (LBP1) and second birth (LBP2) in breeding sows exposed to PRRS virus. The study included 100 pregnant females of the Landrace(¾)/ Yorkshire(¼) line, 75 of which were infected with the PRRS virus and 25 were free of PRRS. Individual blood samples (6-8 drops) were obtained and spotted onto FTA cards and subsequently processed for DNA extraction, which was genotyped using a 10,000 SNP chip for genomic profile. Resulting genotypes were analyzed using a multi-locus mixed model that detected three SNP associated to LBP1 and five SNP associated to LBP2 (P<0.001). These eight SNP were validated using an associative mixed effects model which included the terms genotype and age of dam as fixed effects, and sire as random effect. Allele substitution effects were estimated using the same model including the term genotype as covariate. The SNP rs81276080, rs81334603 and rs80947173 were associated to LBP1 (P<0.001), whereas the SNP rs81364943, rs80859829, rs80895640, rs80893794 and rs81245908 were associated to LBP2 (P<0.001). Only two SNP were in functional chromosomal regions and the remainder SNP were within an intergenic position. In conclusion, these results suggest the existence of gene variants associated with the reproductive performance of sows infected with the PRRS virus
EVIDENT 3 Study: A randomized, controlled clinical trial to reduce inactivity and caloric intake in sedentary and overweight or obese people using a smartphone application: Study protocol
Introduction: Mobile technology, when included within multicomponent interventions, could contribute to more effective weight loss. The objective of this project is to assess the impact of adding the use of the EVIDENT 3 application, designed to promote healthy living habits, to traditional modification strategies employed for weight loss. Other targeted behaviors (walking, caloric-intake, sitting time) and outcomes (quality of life, inflammatory markers, measurements of arterial aging) will also be evaluated. Methods: Randomized, multicentre clinical trial with 2 parallel groups. The study will be conducted in the primary care setting and will include 700 subjects 20 to 65 years, with a body mass index (27.5-40kg/m2), who are clinically classified as sedentary. The primary outcome will be weight loss. Secondary outcomes will include change in walking (steps/d), sitting time (min/wk), caloric intake (kcal/d), quality of life, arterial aging (augmentation index), and pro-inflammatory marker levels. Outcomes will be measured at baseline, after 3 months, and after 1 year. Participants will be randomly assigned to either the intervention group (IG) or the control group (CG). Both groups will receive the traditional primary care lifestyle counseling prior to randomization. The subjects in the IG will be lent a smartphone and a smartband for a 3-month period, corresponding to the length of the intervention. The EVIDENT 3 application integrates the information collected by the smartband on physical activity and the self-reported information by participants on daily food intake. Using this information, the application generates recommendations and personalized goals for weight loss. Discussion: There is a great diversity in the applications used obtaining different results on lifestyle improvement and weight loss. The populations studied are not homogeneous and generate different results. The results of this study will help our understanding of the efficacy of new technologies, combined with traditional counseling, towards reducing obesity and enabling healthier lifestyles. Ethicsanddissemination: The study was approved by the Clinical Research Ethics Committee of the Health Area of Salamanca ("CREC of Health Area of Salamanca") on April 2016. A SPIRIT checklist is available for this protocol. The trial was registered in ClinicalTrials.gov provided by the US National Library of Medicine-number NCT03175614
Trimethylamine-N-Oxide (TMAO) Predicts Cardiovascular Mortality in Peripheral Artery Disease
Peripheral artery disease (PAD) is a major cause of acute and chronic illness, with extremely poor prognosis that remains underdiagnosed and undertreated. Trimethylamine-N-Oxide (TMAO), a gut derived metabolite, has been associated with atherosclerotic burden. We determined plasma levels of TMAO by mass spectrometry and evaluated their association with PAD severity and prognosis. 262 symptomatic PAD patients (mean age 70 years, 87% men) categorized in intermittent claudication (IC, n = 147) and critical limb ischemia (CLI, n = 115) were followed-up for a mean average of 4 years (min 1-max 102 months). TMAO levels were increased in CLI compared to IC (P 2.26 µmol/L exhibited higher risk of cardiovascular death (sub-hazard ratios ≥2, P < 0.05) that remained significant after adjustment for confounding factors. TMAO levels were associated to disease severity and CV-mortality in our cohort, suggesting an improvement of PAD prognosis with the measurement of TMAO. Overall, our results indicate that the intestinal bacterial function, together with the activity of key hepatic enzymes for TMA oxidation (FMO3) and renal function, should be considered when designing therapeutic strategies to control gut-derived metabolites in vascular patients
Host age and expression of genes involved in red blood cell invasion in Plasmodium falciparum field isolates
Plasmodium falciparum proteins involved in erythrocyte invasion
are main targets of acquired immunity and important vaccine
candidates. We hypothesized that anti-parasite immunity acquired
upon exposure would limit invasion-related gene (IRG) expression
and affect the clinical impact of the infection. 11 IRG
transcript levels were measured in P. falciparum isolates by
RT-PCR, and IgG/IgM against invasion ligands by Luminex(R), in
50 Mozambican adults, 25 children with severe malaria (SM) and
25 with uncomplicated malaria (UM). IRG expression differences
among groups and associations between IRG expression and
clinical/immunologic parameters were assessed. IRG expression
diversity was higher in parasites infecting children than adults
(p = 0.022). eba140 and ptramp expression decreased with age (p
= 0.003 and 0.007, respectively) whereas p41 expression
increased (p = 0.022). pfrh5 reduction in expression was abrupt
early in life. Parasite density decreased with increasing pfrh5
expression (p < 0.001) and, only in children, parasite
density increased with p41 expression (p = 0.007), and decreased
with eba175 (p = 0.013). Antibody responses and IRG expression
were not associated. In conclusion, IRG expression is associated
with age and parasite density, but not with specific antibody
responses in the acute phase of infection. Our results confirm
the importance of multi-antigen vaccines development to avoid
parasite immune escape when tested in malaria-exposed
individuals
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