Dietary selenium- and vitamin E-induced alterations in some rabbit tissues

The present study was designed to investigate and compare the effects of dietary selenium (Se) and vitamin E on some physiological parameters and histological changes in liver, heart, and skin tissues, as well as the blood parameters and the related enzymes. Both sex young rabbits were fed with deficient (9.8 micrograms/kg diet), adequate (225 micrograms/kg diet), and rich (4.2 mg/kg diet) Se and vitamin E diets for 12-15 wk for this purpose. As the plasma Se levels and the erythrocyte glutathione (GSH) peroxidase activity decreased (79.8 +/- 9.4 ng/mL and 2.0 +/- 0.3 U/g Hb, respectively) in the deficient group, these values increased (100.4 +/- 2.7 ng/mL and 14.5 +/- 4.3 U/g Hb) in the rich group significantly with respect to the control group. The other antioxidant enzyme activities and the related element levels did not change significantly in either one of the experimental groups. Although the platelet counts of the two experimental groups were not different from the control values, the collagen and the adenosine diphosphate (ADP) stimulated platelet aggregation rate and intensity increased in the deficient group (p < 0.05) and decreased very significantly (p < 0.001) in the rich group. In both of the experimental groups, as the percentage values of the neutrophils decreased, the lymphocytes and the eosinophils increased significantly. According to the light microscopic investigations, the observed lesions of considerable intensity within the tissues that elicit cell degenerations were more pronounced in the animals fed with the rich diet than in those fed with the deficient diet. The deficiency as well as toxicity of Se and the deficiency of vitamin E caused several alterations in the physiological functions of the tissues, and these alterations were supported by the histological lesions within these tissues.     

Capacitor-Discharge Joining of Oxide Ceramics

A capacitor-discharge joining technique has been used to fabricate alumina–metal–alumina and zirconia–metal– zirconia joints using thin foils of aluminum, titanium, or amorphous Al_x Ni_y Y_z alloys as interlayers. The technique involves passing a high-energy pulse through a conductive interlayer, so converting the interlayer into a liquid-vapor "energized foil" which wets and bonds the pieces of ceramic being joined. The bond strengths of the joints were mea-sured by shear testing which showed that the highest bond strengths for both alumina and zirconia substrates were obtained when an amorphous Al_x Ni_y Y_z interlayer was used. An investigation of the interfacial structure of the joints revealed that there is a distinct reaction layer between the ceramic substrate grains and the amorphous Al_x Ni_y Y_z interlayer.     

Fabricating a new immobilization matrix based on a conjugated polymer and application as a glucose biosensor

A new monomer named 4-(dihexylamino)9,12-di(thiophen-2-yl)-7H-benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (ThBN) is synthesized and used as a potential glucose biosensor after electropolymerization of the ThBN on the graphite pencil electrode. The amount of glucose is determined according to the decrease in the amount of oxygen by using cyclic voltammetry technique. Herein, conjugated polymer of ThBN is used as a immobilization matrix. The synthesized PThBN is found to be effective enzymatic biosensor having wide linear glucose determination range between 2.975 × 10⁻³ and 2.087 mM with a limit of detection of 0.0304 mM and a sensitivity of 0.1326 μA/mM cm². This potential enzymatic biosensor has been also tested in commercial samples and found to be useful to detect the glucose concentration.     

A new feature encoding scheme for HIV-1 protease cleavage site prediction

HIV-1 protease has been the subject of intense research for deciphering HIV-1 virus replication process for decades. Knowledge of the substrate specificity of HIV-1 protease will enlighten the way of development of HIV-1 protease inhibitors. In the prediction of HIV-1 protease cleavage site techniques, various feature encoding techniques and machine learning algorithms have been used frequently. In this paper, a new feature amino acid encoding scheme is proposed to predict HIV-1 protease cleavage sites. In the proposed method, we combined orthonormal encoding and Taylor’s venn-diagram. We used linear support vector machines as the classifier in the tests. We also analyzed our technique by comparing some feature encoding techniques. The tests are carried out on PR-1625 and PR-3261 datasets. Experimental results show that our amino acid encoding technique leads to better classification performance than other encoding techniques on a standalone classifier.     

Study of the Free Surface Flow on an Ogee-Crested Fish Bypass

A study of the free surface flow on an ogee-crested fish bypass is presented. The commercial computational fluid dynamics (CFD) code Fluent 6.1 was used to perform the simulations. Structured/unstructured hybrid grids were used to accommodate the complex geometry that included gate slots, flow control gates, and an aeration slot. The volume of fluid (VOF) approach was used to model the water/air interface. The fish bypass exhibits complex free surface features including free nappes and air entrainment from the air slots. Free surface elevations on both sides of the nappe, pressure along the ogee surface, and discharge rating curves were compared against 1:24 experimental data from the laboratory model for different headwater elevations and gate settings. Limited comparison against measured velocities was also performed. Once deemed reliable through validation against experimental data, the computational model was used to analyze the flow field, supplementing the areas of limited experimental data. Though the paper presents the final fish bypass design, CFD was used to guide the design process and provide insight for several variations in the geometry.     

The effect of wollastonite incorporation on the linear firing shrinkage and flexural strength of dental aluminous core ceramics: A preliminary study

The aim of this study is to evaluate the effect of wollastonite (CaSiO3) material on the linear firing shrinkage and flexural strength of dental aluminous core porcelain. Twenty five specimens were prepared in a manner that each five of them contained 0%, 2%, 3%, 4%, and 5% wollastonite by weight. The linear firing shrinkage values were determined according to the formula given in the standard ANSI/ADA (American National Standards Institute/American Dental Association) 69 and the flexural strength of the specimens was evaluated using 3-point bending test. The results of this study showed that addition of wollastonite reduced the linear firing shrinkage and increased the flexural strength of dental aluminous core porcelain. The highest reduction (approx. 20%) in the linear firing shrinkage was obtained by the addition of 5% wollastonite. Kruskal–Wallis test found a statistically significant difference among the mean linear firing shrinkage values of the porcelain groups at the 95% confidence level (p < 0.05). Mann Whitney U statistical test was performed to demonstrate which porcelain groups show statistically significant difference. In spite of achieving 30% increase in the flexural strength by the addition of 2% wollastonite, no statistically significant difference was found among the mean flexural strength values of the porcelain groups (p > 0.05).     

Oriented assembly and nanofabrication of zeolite A monolayers

A facile and efficient method in order to assemble zeolites for the purpose of generating zeolite nano-micropatterns on the Si wafer was investigated by using e-beam lithography. A monolayer of organized, fully covered and strongly bound zeolite A nanocrystals were formed on the Si wafer substrates without using any chemical linkers. The limits of forming nano sized zeolite A patterns on the Si wafer was tested and it was observed that zeolite A nanocrystals could be assembled on the Si wafers with high precision. The limit of the pattern resolution was defined by the size of the zeolite nanocrystal, which was around 250 nm in the current study. Furthermore, mono and double layers of zeolite A nanocrystals were generated without using any chemical linkers on the substrates for the first time.     

Influence of sn‐1,3‐lipase‐catalysed interesterification on the oxidative stability of soybean oil‐based structured lipids

The oxidative stability of structured lipids (SLs) synthesised by specific sn‐1,3‐lipase catalysed interesterification of soybean oil (SBO) with caprylic acid (CA) in a stirred batch reactor was studied. SLs contained considerable amounts of tocopherol (TOH) isomers, although they lost almost 25% of endogenous TOHs during production. The effects of the addition of different TOH homologues (α, β, γ, δ), ascorbyl palmitate (AP, 200 ppm), lecithin (Le, 1000 ppm), butylated hydroxytoluene (BHT, 100 ppm) and butylated hydroxyanisole (BHA, 100 ppm) on the oxidative stability of SLs were investigated. Induction time (IT) of SBO, determined by the Rancimat method, decreased from 8.4 to 5.8 h at 110 °C after the modification. On the other hand, purified SLs and purified SBO had the same IT due to the tocopherol reduction during silica purification. No significant difference was observed between IT of SLs and SLs plus different α‐tocopherol concentrations (50, 100, 150, 200, 300, 500 and 1000 ppm) (P > 0.05). However, the addition of Le and/or AP significantly improved oxidative stability of purified SLs and SBO. The ternary blend containing δ‐TOH, AP and Le had higher IT than ternary blends of α‐TOH, β‐TOH or γ‐TOH. Furthermore, ternary blend containing BHA, AP and Le had higher IT than ternary blends of BHT, AP and Le. In addition, there was an increase in peroxide value (PV), conjugated diene (CD) content and p‐anisidine value (AV) during oxidation of oils at 60 °C. Antioxidant mixtures of α‐TOH (50 ppm) and δ‐TOH (500 ppm) with AP and Le decreased PV, CD and AV effectively. Copyright © 2006 Society of Chemical Industry