Hepatic cholesterol metabolism in experimental nephrotic syndrome

Hypercholesterolemia is a consistent feature of the nephrotic syndrome. However, the mechanisms underlying this perturbation are unclear. In the present work, we have investigated different factors that influence hepatic cholesterol metabolism using the nephrotic rat as a model. The induction of nephrosis resulted in a severe and sustained hypercholesterolemia. However, no effect on the rate-limiting enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl CoA reductase, could be detected. Further, plasma lathosterol/cholesterol ratio, a measure of cholesterol synthesis, was not altered. Also, plasma levels of mevalonate, both a substrate for cholesterogenesis beyond the rate-limiting step and a marker for cholesterol synthesis, did not differ between control rats and those with established hypercholesterolemia. There was no detectable change in the expression of low density lipoprotein (LDL) receptor between the two experimental groups. We conclude that the early increase in cholesterol synthesis reported after the induction of nephrosis is not necessary for the maintenance of hypercholeserolemia. Established hypercholesterolemia of the nephrotic syndrome seems to represent a steady state in which neither enhanced hepatic cholesterol synthesis nor retarded LDL cholesterol clearance is of major importance.     

Feasibility of using digital speckle correlation in the study of seal contacts

This paper presents studies of the contact between a soft rubber specimen and glass counterface using the Digital Speckle Correlation method, which provides information of displacements and structural similarities between recorded images. The setup is designed with a real contact and changes in the contact can be varied. Microscopic images using laser light illumination for different displacements are recorded and correlated. The results show that the contact area can be identified both for dry and lubricated contacts. The method can be applied on different geometries, surface roughness and lubricants. Influences of scars and contaminations, e.g. wear particles, may also be analysed. Copyright © 2009 John Wiley & Sons, Ltd.     

Modeling nonspecific toxicity of organic compounds to the fathead minnow fish by means of chromatographic systems

The performance of chromatographic systems to mimic aquatic toxicity to the fathead minnow fish is evaluated taking into account the factors that contribute to the variance of biological-chromatographic correlations. These factors are the precision to measure the fathead minnow toxicity, the precision of the surrogate chromatographic system, and the error from the dissimilarity between the fathead minnow and chromatographic systems. The precisions are estimated through the characterization of the systems by the solvation parameter model. Several chromatographic systems as well as the common reference octanol-water partition system have been selected to test their ability to model the nonspecific toxicity to the fathead minnow by means of the proposed approach. Predictions and experimental tests show that the micellar electrokinetic chromatography system of sodium taurocholate and chromatographic measurements using an immobilized artificial membrane column provide the most precise estimations of this biopartitioning property. The octanol-water partition system, the conventional C18 high-performance liquid chromatography systems, and the micellar electrokinetic chromatography system of sodium dodecylsulfate show worse performances.     

Estimation of biological properties by means of chromatographic systems: evaluation of the factors that contribute to the variance of biological-chromatographic correlations

The performance of chromatographic systems to emulate biological systems is evaluated in terms of the precision that can be achieved. The variance obtained when biological parameters are correlated against physicochemical ones can be decomposed in three terms: the variance of the biological data, the variance of the physicochemical data, and the variance caused by the dissimilarity between the two correlated systems (biological and physicochemical). The three terms contribute to the overall variance observed when measurements in chromatographic systems are correlated with experimental biological properties. The Abraham linear free energy relationships (LFERs) provide a very good approach to characterize biological and physicochemical systems and thus the variance of the analyzed data and the similarity/dissimilarity between them. The contribution of the three variances to the precision of the biological parameter estimated in this way is evaluated from the characterization of the biological and chromatographic systems by means of the Abraham model. The proposed method is able to estimate the goodness of chromatographic systems to predict particular biological properties. In particular, this method is illustrated by comparison of toxicity data (-log LC(50)) for the fish fathead minnow with retention data (log k) in several micellar electrokinetic chromatography (MEKC) systems and also by correlations between retention data (log k) in the sodium taurocholate (STC) MEKC system and data of several biological systems.     

Endothelium-dependent vasodilator and antioxidant properties of a novel enzymatic extract of grape pomace from wine industrial waste

The aim of the present study was to evaluate the vascular effects of an enzymatic extract of grape pomace (GP-EE) on isolated arteries, focusing our attention on endothelium-derived relaxation and on its antioxidant properties. Grape pomace derived from wine making was extracted by an enzymatic process and its composition of polyphenols was evaluated by HPLC and ESI-MS/MS, detecting kaempferol, catechin, quercetin and procyanidins B1 and B2, trace levels of resveratrol and tracing out gallocatechin and anthocyanidins. GP-EE induced endothelium- and NO-dependent vasodilatation of both rat aorta and small mesenteric artery (SMA) segments and reduced Phe-induced response in aortic rings. Both ORAC and DPPH assays confirmed antioxidant scavenging properties of GP-EE, which also prevented O(2)(·-) production (assessed by DHE fluorescence) and contraction elicited by ET-1. These results provide evidence that GP-EE possesses interesting antioxidant and protective vascular properties and highlight the potential interest of this extract as a functional food.     

Effects of dietary rosemary extract on lamb spoilage under retail display conditions

A dietary rosemary extract (RE) was tested to extend the shelf life of raw lamb meat. Lambs were supplemented with 0.6 mg kg⁻¹ RE during fattening (from 13 to 25 kg live weight). Meat spoilage (total viable counts, psycrophilic bacteria, Enterobacteriaceae, molds and yeasts), TBARS, CIE L*a*b* color and the sensory traits of lamb cuts were analyzed on days 0, 7, 14 or 21 under retail display conditions (70/30 O₂/CO₂ atmosphere, 2 °C temperature and 1600 lx lighting). Supplementation of the lamb diet with RE was effective (P < 0.05) in prolonging the time chilled-packed lamb cuts could be kept under retail display conditions. Dietary rosemary clearly inhibited lipid oxidation and rancidity, and was moderately efficient in preventing sensory deterioration and microbial spoilage. Although the results concerning meat preservation were limited, the dietary use of rosemary extracts in lambs seems to be promising as a nutritional strategy for improving meat quality.     

Modulus of elasticity of I-214 young poplar wood from standing trees to sawn timber: influence of the age and stand density

The poplar wood industry chain from planted forests takes a strategic position for the creation of a competitive, profitable, and highly technological bioeconomy in the world. Niche sectors such as buildings can find in poplar wood an effective ally to reduce its carbon footprint and ecological backpack. For the poplar wood, it is important to understand the huge significance of the proper silvicultural management of a plantation and to characterize the raw material. In this context, this paper carries out such characterization for the particular case of young plantations of the clone I-214 (Populus × euroamericana (Dode) Guinier), commonly used for its high growth rate. The acoustic non-destructive characterization of poplar wood is carried out from standing trees, logs and sawn timber and then compared with the one obtained through destructive mechanical tests. The study shows that growth parameters are highly affected by the age and moderately affected by stand density, while mechanical properties are strongly affected by the age and less affected by the stand density. The study also shows high values of the linear regression coefficients between the mechanical properties obtained on standing trees, logs, and sawn timber using non-destructive and destructive methods (R²?=?0.7 for all three cases), greater than those obtained for other species. A good linear fitting was obtained between the tree and log velocities (R²?=?0.76) and between the tree and log elastic moduli (R²?=?0.85). Consequently, the evaluation of the mechanical properties employing the optimized acoustic protocol provides a reliable characterization for the poplar wood.

     

Integration of enterprise levels based on an ontological framework

Enterprises are highly complex systems in which one or more organizations share a definite mission, goals and objectives to offer a product or service. In this study, an ontological framework is built as a mechanism for exchanging information and knowledge models for multiple applications and effective integration between hierarchical levels. The potential of the general semantic framework that is developed is demonstrated using a case study concerning the enterprise supply chain network design-planning problem.     

Separate Bleaching of Pulp Fractions Enriched in Earlywood and Latewood Fibers

Abstract

Unbleached softwood kraft pulp was fractionated in hydrocyclones into a fine fraction, enriched in earlywood fibers, and a coarse fraction, enriched in latewood fibers. The response to individual bleaching chemicals and the bleachability in bleaching sequences of the pulp fractions was studied.

The light absorption coefficient, light scattering coeffient, and brightness were higher in the unbleached fine fraction than in the coarse fraction. Hydrogen peroxide managed to reduce the light absorption coefficient of the earlywood enriched fine fraction more efficiently than that of the latewood enriched fraction.

In the TCF‐sequence the light absorption coefficient of the fine fraction was reduced to the level of the coarse fraction at a given consumption of bleaching chemicals. In the ECF‐sequence the difference in light absorption coefficient remained between the fractions. At a given consumption of bleaching chemicals, the fine fraction had higher brightness than the coarse fraction, 2%‐ and 1%‐units on the ISO‐scale in the TCF and ECF bleaching sequence, respectively.