Response surface method applied to optimization of estradiol permeation in chitosan membranes

The present work deals with the study of estradiol permeation in chitosan membranes. A fractional factorial design was built for the determination of the main factors affecting estradiol permeation. The independent factors analysed were: concentration of chitosan, concentration of cross-linking agent, cross-linking time and thermal treatment. It was found that concentration of chitosan and cross-linking time significantly affected the response. The effects of thermal treatment and concentration of cross-linking agent were not significant. An optimization process based on response surface methodology was carried out in order to develop a statistical model which describes the relationship between active independent variables and estradiol flux. This model can be used to find out a combination of factor levels during response optimization. Possible options for response optimization are to maximize, minimize or move towards a target value.     

Effect of mechanical treatments applied to milk fat on fat retention and lipolysis in minicurds

The aim of this work was to identify a treatment on milk fat, applicable to pretreat cheese milk, which could enhance lipolysis. Three factors were studied in milk fat mixtures: physical treatment (pumping and mechanical agitation), temperature (5, 15, and 45°C) and fat content (5%, 15%, and 30%). Damage to fat globule was estimated by assessing free fat and by phase contrast microscopy. Moderate damage was achieved in a mixture of 30% of fat, treated with mechanical agitation at 2800 rpm/2 min at 5°C. Applying this procedure to prepare minicurds did not modify values of fat content, moisture and lipolysis.     

New evidence for a role of Bisphenol A in cell integrity. Implications in the human population

Bisphenol A (BPA) is a xenoestrogen known for its implications for the endocrine systems and several other organs, including the kidneys. Recent renal studies have shown that BPA can induce alterations of the cytoskeleton and cell adhesion mechanisms such as a podocytopathy with proteinuria and hypertension, alterations involved in the progression of renal diseases. These data and the fact that BPA is known to be present in the urine of almost the entire population strongly suggest the critical need to reevaluate BPA exposures considered safe.     

Shear-flexural strength mechanical model for the design and assessment of reinforced concrete beams subjected to point or distributed loads

A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction at ultimate limit state. The predictions of the model have been compared to those obtained by using the EC2, MC2010 and ACI 318-08 provisions and they fit very well the available experimental results from the recently published ACI-DAfStb databases of shear tests on slender reinforced concrete beams with and without stirrups. Finally, a detailed application example has been presented, obtaining each contributing component to the shear strength and the assumed shape and position of the critical crack.     

WT-1 mRNA expression is modulated by nitric oxide availability and Hsp70 interaction after neonatal unilateral ureteral

Wilms tumor gene 1 (wt-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy, leading to apoptosis. There is a functional interaction between WT-1 and inducible nitric oxide synthase (iNOS). In this regard, we reported that after neonatal unilateral ureteral obstruction, rosuvastatin prevents apoptosis through an increase in nitric oxide bioavailability, which in turn is linked to higher Hsp70 expression. Hence, the goal of this study was to determine whether a nitric oxide/Hsp70 interaction is involved in changes in WT-1 mRNA expression after ureteral obstruction. Neonatal rats submitted to experimental ureteral obstruction were treated with either vehicle or rosuvastatin for 14 days. Decreased nitric oxide and iNOS/Hsp70 expression associated with WT-1 low expression was shown in obstructed kidneys. Apoptosis was induced and it was associated with an increased Bax/BcL2 ratio. Conversely, iNOS/Hsp70 upregulation and an increased WT-1 mRNA expression, without an apoptotic response, were observed in the cortex of obstructed kidneys of rosuvastatin-treated rats. Nitric oxide also modulated Hsp70 and WT-1 mRNA expression in MDCK cells. Finally, in vivo experiments with nitric oxide modulators support our hypothesis that WT-1 mRNA expression is associated with nitric oxide level. Results suggest that rosuvastatin may modulate WT-1 mRNA expression through renal nitric oxide bioavailability, preventing neonatal obstruction-induced apoptosis associated with Hsp70 interaction.     

USE OF IMMERSION AND VACUUM IMPREGNATION IN MARINATED SALMON (SALMO SALAR) PRODUCTION

The kinetics of mass transfer during the production of marinated salmon were compared for the traditional dry processing method (D) and alternative processes involving immersion in ternary solution (sucrose and NaCl), both at atmospheric pressure (I) and with vacuum pulse (VI). The evolution of water activity, moisture, salt and sugar content and weight loss was measured during marination trials. Immersion marination (I and VI) processes reduced both the process time (approximately 85%) and the weight loss (approximately 48%), increasing yield.

PRACTICAL APPLICATIONS

The results of this article can be used by processing industries for the elaboration of salmon. The technologies of marinating salmon by immersion in ternary solution, with (IV) and without (I) vacuum pulse, have advantages in comparison with dry marinating technology. These are related principally to a reduction of processing time by 50% and of weight loss by 48%. Considering the growth of the production and consumption of salmon at a world level, we think that marinating technologies by immersion in an osmotic solution represent a good alternative to the industrialized production of marinated salmon.     

THE COMBINATORIAL ANT SYSTEM

This paper presents a new distributed algorithm based on Ant System (AS) concepts called Combinatorial Ant System (CAS). It is oriented to solve static discrete-state combinatorial optimization problems. Our approach consists of mapping the solution space of the combinatorial optimization problem in the space where the ants will walk, and defining the transition probability and the pheromone update formula of the Ant System, according to the objective function of the Combinatorial Optimization Problem. We test our approach on the graph partitioning, graph coloring and traveling salesman problems.     

Fractions of a chloroform extract of ajenjo leaves (<i>Artemisia mendozana</i> DC. var. <i>mendozana</i>) inhibit the proliferation,viability and clonogenicity of B16-F0 melanoma cells

The ajenjo, Artemisia mendozana DC. var. mendozana (Asteraceae), grows in the Andean foothills of Mendozaand San Juan, Argentina, and is used as a medicinal plant for its antispasmodic and antifungal properties. The aim of thiswork was to obtain fractions of a chloroform extract of ajenjo leaves and to evaluate the in vitro effects on proliferation,viability and clonogenicity of B16-F0 melanoma cells. Using a silica gel chromatography column, 120 fractions werecollected and grouped according to the chromatographic profile in 9 main fractions (F1–F9). Their major compoundsidentified were: terpenes (F1), terpenes and sesquiterpene lactones (F2–F3), sesquiterpenes (F4–F6) and phenols andsesquiterpenes (F7-9). B16-F0 cells were incubated for 72 h with DMSO (vehicle) or 0.1 mg/ml F1–F9. At 72 h ofculture, F1 decreased both the growing index (GI) and cell viability. F2 and F3 both decreased GI and only F3decreased clonogenic activity. F4 and F5 both decreased GI. Only F5 decreased cell viability and F4 decreasedclonogenicity. Consequently, fractions F6–F8 did not affect any of the cell parameters assayed, while F9 decreased cellviability and inhibited clonogenicity.