14,121 research outputs found
Association between pruritus and serum concentrations of parathormone, calcium and phosphorus in hemodialysis patients.
Chronic renal disorders have a progressive course in most cases, and finally result in end-stage renal disease (ESRD). Hemodialysis (HD) is one of the mainstays in the treatment of these patients. Disturbance in calcium (Ca) and phosphorus (P) metabolism and alteration of serum levels of parathormone (PTH) are observed in these patients. One of the most common cutaneous manifestations in patients on HD is pruritus. The aim of this study is to evaluate the association between pruritus and serum concentrations of Ca, P and PTH in patients with chronic renal disease. This analytic, descriptive, cross-sectional study was performed on 120 patients on HD at the Fifth-Azar Hospital in Gorgan, Iran, in 2010. Information related to the patients, including age, gender, pruritus, time of pruritus and duration on dialysis, was extracted from questionnaires. Serum concentrations of intact PTH, Ca and P were measured. Data were analyzed by the chi-square test and SPSS-16 software. A P-value less than 0.05 was considered statistically significant. Among the 120 study patients, 50% were male and the mean age (±SD) was 49 ± 12.3 years. Sixty percent of the patients had pruritus, of whom 33.3% had PTH levels above the normal range. Among the 40% of the patients who did not have pruritus, 39.6% had PTH levels higher than the normal levels. The mean serum Ca and P levels were 8.44 ± 1.65 mg/dL and 5.48 ± 1.81 mg/dL, respectively. The mean (±SD) Ca-P product was 55.46 ± 47.16 and the mean PTH concentration was 274.34 ± 286.53 pg/mL. No significant association was found between pruritus and age, sex, serum PTH and P levels as well as Ca-P product. However, the association between serum Ca levels and pruritus was significant (P = 0.03). Our study showed that most patients with pruritus had serum Ca levels in the abnormal range (lower or higher), and there was no significant correlation between serum iPTH level and pruritis. Thus, good control of serum Ca levels is important to reduce pruritus in these patients
Multi-objective optimisation of bio-based thermal insulation materials in building envelopes considering condensation risk
The reduction in energy demand for heating and cooling with insulation materials increases the material related environmental impact. Thus, implementing low embodied energy materials may equilibrate this trade-off. Actual trends in passive house postulate bio-based materials as an alternative to conventional ones. Despite that, the implementation of those insulators should be carried out with a deeper analysis due to their hygroscopic properties. The moisture transfer, the associated condensation risk and the energy consumption for seven biobased materials and polyurethane for a building-like cubicle are analysed. The performance is evaluated combining a software application to model the cubicle (EnergyPlus) and a tool to optimize its performance (jEPlus). The novelty of this optimization approach is to include and evaluate the effects of moisture in these insulation materials, taking into account the mass transfer through the different layers and the evaporation of the different materials. This methodology helps optimise the insulation type and thickness verifying the condensation risk, preventing the deterioration of the materials. The total cost of the different solutions is quantified, and the environmental impact is determined using the life cycle assessment methodology. The effect of climate conditions and the envelope configuration, as well as the risk of condensation, are quantified. The results show that cost and environmental impact can be reduced if bio-based materials are used instead of conventional ones, especially in semiarid climates. Condensation risk occurs for large thicknesses and in humid climates. In our case studies, hemp offered the most balanced solution.The authors would like to acknowledge financial support from the Spanish Government (CTQ2016-77968-C3-1-P, ENE2015-64117-C5-1-R, ENE2015-64117-C5-3-R, MINECO/FEDER, UE). The research leading to these results has received funding from the European Commission Seventh Framework Programme under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE). This project has received funding the European Union's Horizon 2020 Research and Innovation Program under grant agreement No 657466 (INPATH-TES). This article has been possible with the support of the Ministerio de Economía y Competitividad (MINECO) and the Universitat Rovira i Virgili (URV) (FJCI-2016-28789). Authors would like to acknowledge the Brazilian Government for their support by the CNPq (National Council for Scientific and Technological Development). M.P. would like to thank the Brazilian Education Ministry for the financial support received under the PNPD/Capes fellowship. L.F.C. would like to thank the Catalan Government for the quality accreditation given to her research group GREA (2014 SGR 123)
Critical properties of an aperiodic model for interacting polymers
We investigate the effects of aperiodic interactions on the critical behavior
of an interacting two-polymer model on hierarchical lattices (equivalent to the
Migadal-Kadanoff approximation for the model on Bravais lattices), via
renormalization-group and tranfer-matrix calculations. The exact
renormalization-group recursion relations always present a symmetric fixed
point, associated with the critical behavior of the underlying uniform model.
If the aperiodic interactions, defined by s ubstitution rules, lead to relevant
geometric fluctuations, this fixed point becomes fully unstable, giving rise to
novel attractors of different nature. We present an explicit example in which
this new attractor is a two-cycle, with critical indices different from the
uniform model. In case of the four-letter Rudin-Shapiro substitution rule, we
find a surprising closed curve whose points are attractors of period two,
associated with a marginal operator. Nevertheless, a scaling analysis indicates
that this attractor may lead to a new critical universality class. In order to
provide an independent confirmation of the scaling results, we turn to a direct
thermodynamic calculation of the specific-heat exponent. The thermodynamic free
energy is obtained from a transfer matrix formalism, which had been previously
introduced for spin systems, and is now extended to the two-polymer model with
aperiodic interactions.Comment: 19 pages, 6 eps figures, to appear in J. Phys A: Math. Ge
CAUSTIQUES EN CHAMP PROCHE GENEREES PAR DES PARTICULES TRANSPARENTES RECONSTRUCTION PAR HOLOGRAPHIE NUMERIQUE EN LIGNE
International audienceL'holographie numerique en ligne est une technique d'imagerie volumetrique particulierement adaptee a la caracterisation spatiale (position, vitesse et tailles/morphologies) des ecoulements particulaires dilues. Dans de nombreux domaines la connaissance de la composition des particules est aussi d'un grand interet. Nous realisons cette mesure avec l'holographie numerique en ligne par l'analyse du champ proche des particules. Dans cette region les contributions des differents processus de diffusion de la lumiere peuvent etre plus facilement distinguees et notamment les caracteristiques du jet photonique (caustique vers l'avant generee par les rayons simplement refractes). La localisation dans l'espace du maximum d'intensite de cette caustique permet d'estimer l'indice de refraction relatif des particules. Dans cette communication, nous montrons que, dans le cadre de l'approximation de Fresnel de la diffraction scalaire, le jet photonique reconstruit par holographie numerique correspond a la tache d'Airy d'une lentille spherique. Par analogie avec les notions d'images virtuelles et reelles employees en optique pour les lentilles convergentes et divergentes, cette tache est restituee de facon reelle pour les particules ayant un indice relatif superieur a un et de facon virtuelle pour les particules dont l'indice relatif est plus petit que l'unite. Ceci fournit une solution simple et numeriquement tres efficace pour differencier ou caracteriser la composition des particules solides, liquides ou gazeuses. Une validation experimentale en laboratoire sur un ecoulement triphasique montre qu'il est desormais possible d'obtenir simultanement la position dans l'espace, la vitesse, la trajectoire, la taille et la composition de particules en ecoulement
Multi-domain large deformations by monolithic approach for massive parallel computing
International audienceA monolithic approach is presented to solve multi-domain large deformations problems. It is based on an eulerian formulation using a fixed yet anisotropic adaptative mesh. Within this context, a level set method is used to capture the interface evolution of different domains. In terms of parallel computing, it is expected that the technique of single mesh and single mechanical solver developed under CimLib allows to obtain easily a very good scalability up to several hundred processors
First measurements of the flux integral with the NIST-4 watt balance
In early 2014, construction of a new watt balance, named NIST-4, has started
at the National Institute of Standards and Technology (NIST). In a watt
balance, the gravitational force of an unknown mass is compensated by an
electromagnetic force produced by a coil in a magnet system. The
electromagnetic force depends on the current in the coil and the magnetic flux
integral. Most watt balances feature an additional calibration mode, referred
to as velocity mode, which allows one to measure the magnetic flux integral to
high precision. In this article we describe first measurements of the flux
integral in the new watt balance. We introduce measurement and data analysis
techniques to assess the quality of the measurements and the adverse effects of
vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum.
Meas. This Journal can be found online at
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1
Bouveret\u27s Syndrome: Literature Review.
It was in 1896 that Bouveret\u27s syndrome acquired its name after the French physician Leon Bouveret, who published two case reports in Revue de Medecin. Bouveret\u27s syndrome describes gastric outlet obstruction secondary to an impacted gallstone. The gallstone reaches the small bowel through a bilioenteric fistula as a consequence of chronic inflammation and adherence between the biliary system and the bowels which increase the intraluminal pressure and leads to secondary wall ischemia and wall perforation with gallstone passage into the bowel. Bouveret\u27s syndrome\u27s prevalence is highest among elderly women. Despite the rarity of Bouveret\u27s syndrome, it can cause notable morbidity and mortality rates. We underwent a review of literature about Bouveret syndrome to increase awareness of its occurrence and potentially life-threatening complications
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