Calcium-sensing receptor gene polymorphisms and cardiac valvular calcification in patients with chronic renal failure: A pilot study

Cardiac valvular calcification (VC) is a frequent finding in chronic hemodialysis patients. In addition to demographic and metabolic factors, genetic susceptibility may also influence the occurrence and severity of these abnormalities and account for interindividual variability among patients. In this report, we studied the relation of calcium-sensing receptor (CaSR) gene polymorphisms to the development of VC in chronic hemodialysis patients. A total of 41 chronic hemodialysis patients (26 male, mean age 47.23 ± 11.36 years vs. 15 females, mean age 48.13 ± 14.66 years) undergoing treatment for more than 1 year were evaluated with transthoracic echocardiography. In patients with and without VC, CaSR gene polymorphisms (A990G, C1011G) were investigated by PCR, using allele-specific primers. In randomly chosen subjects, PCR analysis was verified by DNA sequencing. Cardiac valve calcification was detected in 21 patients (51.2%). Five of these patients (12.2%) had mitral valve calcification, 4 (9.75%) had aortic valve calcification, and 12 (29.27%) had both. In patients with VC, the frequency of the A/G genotype was slightly higher than those with no VC with a borderline P value (42.9% vs. 15%, χ²=3.840, P=0.050). The frequency of the C/C genotype was similar in patients with and without VC (90.5% vs. 85%, P>0.05). The results of this study are not enough to prove the role of CaSR gene polymorphisms in the development of VC. There is a need for large-scale studies on this topic.     

EXPERIMENTAL DETERMINATION OF MASS TRANSFER COEFFICIENT: MOISTURE CONTENT AND HUMIDITY RATIO DRIVING FORCE APPROACHES DURING BAKING

Moisture distribution in baked products at the end of baking is important because it directly affects the product's quality. In fact, nonhomogeneous moisture distribution may result in quality defects such as cracking, checking etc. Diffusion inside and convective mass transfer outside the product are important factors affecting the quality. Therefore, accurate values of mass transfer parameters should be known for optimization of the baking process to obtain a product of higher quality. For this objective, infinite mass transfer and constant diffusion coefficient simplifying approximations have been applied in the literature numerous times to develop mass transfer models. However, the infinite mass transfer coefficient approximation may not hold true, especially under natural convection conditions. To evaluate the mass transfer coefficient, baking experiments were carried out to obtain the moisture content changes of cookies during baking at 190, 200 and 210C under natural and forced convection conditions. Then, mass transfer coefficient was determined using the moisture content difference and the humidity ratio difference as the driving force for mass transfer. The results of these two approaches were compared, and the use of humidity ratio difference seemed to be a better approach in terms of reflecting actual process conditions because it is based on the surface changes.     

NONENZYMIC BROWNING REACTIONS IN MULTI SUGAR AND AMINO ACID SYSTEMS

Accelerated storage tests were carried out for accumulation of 5-hydroxy methyl furfural (HMF) and brown pigment formation (BPF) in the model systems containing more than one sugar and amino acid. In these tests, the effects of temperature and amino acid type were investigated at pH 3.5. In the model systems with glutamine or arginine, the accumulation of HMF and BPF were higher than the model systems containing proline at 55, 65 and 75C. The presence of more than one amino acid in the model caused an additive increase in HMF accumulation and BPF. The effect of temperature on both HMF accumulation and BPF were significant (P < 0.05). Both HMF accumulation and BPF were affected significantly (P < 0.05) by the addition of amino acid(s) into sugar solution.     

The several elements of intestinal innate immune system at the beginning of the life of broiler chicks

Functional capacity of digestive system and intestinal adaptive immunity are immature at hatching of broiler chicks. Therefore, intestinal innate immunity after hatching is vital to young chicks. The purpose of this study was to investigate expression and tissue distributions of several elements of the innate immune system (i.e., TLR2, TLR4, CD83, and MHC class II expressing cells) in the intestine of one‐day‐old chicks. For this purpose, ileum and cecum were examined the under different conditions, which included the control and 1, 3, 6, 12, or 24 h after injection of lipopolysaccharide (LPS) and phosphate buffered saline. The findings indicated that regardless of the antigenic stimulation, Toll‐like receptor (TLR) 2 and TLR4 expressing cells were present in the intestinal tissues of one‐day‐old chicks. We noticed that the intestinal segments have different TLR expression levels after LPS stimulation. Dendritic cells were identified, and they left the intestinal tissue after LPS treatment. MHC class II molecules were diffusely present in both the ileum and cecum. This study demonstrates that the intestinal tissue of one‐day‐old chicks has remarkable defensive material, including histological properties and several elements of the innate immune system. Microsc. Res. Tech. 79:604–614, 2016. © 2016 Wiley Periodicals, Inc.     

Influence of recycled polyethylene terephthalate fibres on plastic shrinkage and mechanical properties of concrete

Polyethylene terephthalate bottles production has drastically increased year after year due to high versatility of polyethylene terephthalate plastics and considerable consumption of beverages. In tandem with that increase, the major concern of society has been the improper disposal of this non-biodegradable material to the environment. To deal with this concern, recycled polyethylene terephthalate bottles were incorporated in concrete as fibre reinforcements in this study. The objective of this research is to evaluate the mechanical properties of recycled polyethylene terephthalate fibre reinforced concrete (RPFRC) in comparison with control concrete without fibres. polyethylene terephthalate fibres with three different diameters (0.45, 0.65, and 1.0 mm) and two lengths (20 and 30 mm) were added at various proportions (0.5%, 1.0%, 1.5% and 2.0%) by volume of concrete in order to determine the effect of fibres initially on compressive, flexural and splitting tensile strengths of concrete. The results revealed that none of the fibres have detrimental effects up to 1% volume fraction, however further addition caused slight reductions on mechanical properties in some conditions. Plastic shrinkage resistance and impact resistance tests were also performed according to related standards. Polyethylene terephthalate fibres were observed to have marked improvements on those properties. Such a good performance could be attributed primarily to the bridging effect of fibres.     

COMPUTER CONTROL OF THYRISTORIZED INDUCTION MOTORS AND ON-LINE PERFORMANCE PREDICTIONS

ABSTRACT

This paper describes a method of modelling the dynamic behaviour of thyristor controlled induction motors. Real time operational verification of the model is achieved by interfacing the drive system to a computer. The steady state torque produced by the motor is described as a function of firing angle, extinction angle and speed. The model concentrates on the open loop transfer functions of induction machines for small perturbations in motor speed and firing angles. The non-linear characteristics of the open loop transfer function has been discussed. The solutions presented here can lead to a comprehensive closed loop analysis for the dynamic behaviour of induction motors in industrial applications.     

A NUMERICAL APPROACH WITH VARIABLE TEMPERATURE BOUNDARY CONDITIONS TO DETERMINE THE EFFECTIVE HEAT TRANSFER COEFFICIENT VALUES DURING BAKING OF COOKIES

The increasing trade of ready‐to‐eat foods such as cookies highlights an interest in quality defects during baking. Heat (h and thermal diffusivity) and mass (mass transfer and diffusion coefficients) transfer parameters are significant parameters affecting the quality changes. Therefore, it is important to determine these parameters for modeling and process optimization studies. Among these, the h is important, revealing the relationship between the heating medium and product surface. As baking involves a simultaneous heat and mass transfer involving moisture diffusion and heat conduction inside and convective heat and mass transfer outside, a lumped system method may not be an accurate choice to determine the h value. Changes in the product volume and contact heating from bottom of the product also bring extra challenges to the determination of h. Therefore, the objective of this study was to use realistic approaches including simultaneous heat and mass transfer to determine the changes in h. The h_effvalues for the bottom and top surface of the cookies were then determined, applying a numerical procedure where the surface temperature changes were the boundary conditions with evaporation on the surface. The h_band h_t values increased with baking temperature and varied with baking time. The results of this study showed that evaporative mass flux for the top surface, heat flux for the bottom surface and the product's volume changes were significant in the variation of h values.