Estimated glomerular filtration rate is a poor predictor of the concentration of middle molecular weight uremic solutes in chronic kidney disease

Background: Uremic solute concentration increases as Glomerular Filtration Rate (GFR) declines. Weak associations were demonstrated between estimated GFR (eGFR) and the concentrations of several small water-soluble and protein-bound uremic solutes (MW500Da). Materials and Methods: In 95 CKD-patients (CKD-stage 2-5 not on dialysis), associations between different eGFR-formulae (creatinine, CystatinC-based or both) and the natural logarithm of the concentration of several LMWP's were analyzed: i.e. parathyroid hormone (PTH), Cystatin C (CystC), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), leptin, retinol binding protein (RbP), immunoglobin light chains kappa and lambda (Ig-kappa and Ig-lambda), beta-2-microglobulin (beta M-2), myoglobin and fibroblast growth factor-23 (FGF-23)). Results: The regression coefficients (R-2) between eGFR, based on the CKD-EPI-Crea-CystC-formula as reference, and the examined LMWP's could be divided into three groups. Most of the LMWP's associated weakly (R-2 0.7). Almost identical R-2-values were found per LMWP for all eGFR-formulae, with exception of CystC and beta M-2 which showed weaker associations with creatinine-based than with CystC-based eGFR. Conclusion: The association between eGFR and the concentration of several LMWP's is inconsistent, with in general low R-2-values. Thus, the use of eGFR to evaluate kidney function does not reflect the concentration of several LMWP's with proven toxic impact in CKD

Heat flow in the postquasistatic approximation

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model which corresponds to an incompressible fluid departing from the static equilibrium, it is not possible to go far from the initial state after the emission of a small amount of energy. Initially collapsing distributions of matter are not permitted. Emission of energy can be considered as a mechanism to avoid the collapse. If the distribution collapses initially and emits one hundredth of the initial mass only the outermost layers evolve. For a model which corresponds to a highly compressed Fermi gas, only the outermost shell can evolve with a shorter hydrodynamic time scale.Comment: 5 pages, 5 figure

Extraction of silymarin compounds from milk thistle (Silybum marianum) seed using hot, liquid water as the solvent

High-value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs occur. When compared to traditional solvents, water is an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A, and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50°C, 70°C, 85°C and 100°C water as a function of time. For taxifolin, silychristin, silybinin A, and silybinin B, extraction with 100°C water resulted in the highest yields. After 210 min of extraction at 100°C, the yield of taxifolin was 1.2 mg/g of seed while the yields of silychristin, silybinin A, and silybinin B were 5.0, 1.8 and 3.3 mg/g of seed, respectively. The ratios of the extracted compounds, and particularly the ratios at long extraction times, showed that the more polar compounds (taxifolin and silychristin) were preferentially extracted at 85°C, while the less polar silybinin was preferentially extracted at 100°C

CMF 056: genótipo de mamoeiro com potencial para cultivo no Ceará.

Disponivel no site da Embrapa Agroindustria Tropical

Avaliação de genótipos de feijão-de-corda sob infecção simultânea por "cowpea aphid-borne mosaic virus" e "cucumber mosaic virus".

Avaliacao genotipos feijao-de-corda sob infeccao simultanea;tem se intensificado, no Estado do Ceara, a infeccao simultanea em feijao-de-corda, Vigna unguiculata(L.)Walp., pelo Potyvirus CpAMV e pelo Cucumovirus CMV, que afetam drasticamente o rendimento da cultura nas principaisregioes produtoras.Visando solucionar o problema, executou-se um trabalho em campo no municipio de Brejo Santo, CE; adotou-se o delineamentoem blocos completos casualizados com quatro repeticoes;coletaram-se amostras de plantas infectadas de cada parcela para exame em laboratorioe os dados para as variaveis...bitstream/CNPAT-2010/4777/1/Bp-025.pd

X-ray tomography of sand-rubber mixtures

The behavior of sand-rubber mixtures is controlled by the mechanisms taking place at the grain scale. Here, we use a mixture of shredded tire and a silica sand with similar grain sizes to investigate granular behavior under one-dimensional compression. A mini-oedometer operating inside an X-ray scanner was used to assess the evolution of the microstructure under loading and unloading. New insights are presented on the development of the contact surfaces between sand and rubber and the evolution of the void space

A new approach to investigate the particle size effects in centrifuge modelling

Geotechnical centrifuge modelling provides an opportunity to examine novel and complex events in a well-controlled and repeatable environment. While grain interaction and contact dynamics are considered in centrifuge modelling, the soil is treated as a continuum, consistent with standard geotechnical analysis. In the last four decades, particle size effects have been normally approached by the ratio of median particle diameter to critical dimension of modelled structure. The current study considers the response of a granular medium in a centrifuge model by coupling physical tests and equivalent discrete element simulations. The response of a strip footing on uniformly graded glass ballotini is investigated. This is chosen as the sample characteristics can be accurately replicated in a discrete element simulation. Particle size distribution, gravity and footing width are scaled in the context of model-the-model technique and the sensitivity of the bulk response to rapid increase in stress level is explored. This will help establishing the link between the micro phenomena and the macro response and contribute towards improving geotechnical design. The paper describes the work conducted to overcome challenges related to physical modelling including particle mixing, sample preparation, image analysis, and loading apparatus

Successor features for transfer in reinforcement learning

Transfer in reinforcement learning refers to the notion that generalization should occur not only within a task but also across tasks. Our focus is on transfer where the reward functions vary across tasks while the environment's dynamics remain the same. The method we propose rests on two key ideas: "successor features," a value function representation that decouples the dynamics of the environment from the rewards, and "generalized policy improvement," a generalization of dynamic programming's policy improvement step that considers a set of policies rather than a single one. Put together, the two ideas lead to an approach that integrates seamlessly within the reinforcement learning framework and allows transfer to take place between tasks without any restriction. The proposed method also provides performance guarantees for the transferred policy even before any learning has taken place. We derive two theorems that set our approach in firm theoretical ground and present experiments that show that it successfully promotes transfer in practice

Avaliação das condições de salinidade, drenagem e fertilidade e alterações químicas ocorridas em areia quartzozas apos cinco anos sob irrigação localizada.

Este trabalho foi conduzido em uma área de areia quartzoza da Fazenda Boa Esperança, em Petrolina-Pe, cultivada c om videira e mangueira. Avaliou-se o efeito d a irrigação e da adubação, aplicadas durante cinco anos, sobre algumas características químicas do solo e aparecimento de lençol freático. O sistema de irrigação utilizado foi micro-aspersão. Amostragem do solo foi feita em 34 pontos da área cultivada, onde estão localizados os poços, para observação do nível do lençol freático. Os resultados analíticos mostraram que houve um aumento da CE das bases trocáveis e do fósforo "disponível" e o aparecimento do lençol freático, na área da videira

Equation of state and transport processes in self--similar spheres

We study the effect of transport processes (diffusion and free--streaming) on a collapsing spherically symmetric distribution of matter in a self--similar space--time. A very simple solution shows interesting features when it is matched with the Vaidya exterior solution. In the mixed case (diffusion and free--streaming), we find a barotropic equation of state in the stationary regime. In the diffusion approximation the gravitational potential at the surface is always constant; if we perturb the stationary state, the system is very stable, recovering the barotropic equation of state as time progresses. In the free--streaming case the self--similar evolution is stationary but with a non--barotropic equation of state.Comment: 9 pages, 2 figure