Redox regulation of signal transduction in vascular smooth muscle cells: thiol oxidizing agents induced phospholipase D

Decrease in intracellular thiols leads to oxidative stress and thus may cause alterations in the activity of redox-sensitive enzymes required for signal transduction. Here, we report that, N-ethylmaleimide and phenylarsine oxide, which are known to oxidize free thiols as well as protein thiols, induced phosphatidyl ethanol generation in the micromolar range suggesting activation of phospholipase D in vascular smooth muscle cells. These agents also induced significant phosphatidic acid and diacylglycerol generation without causing protein kinase C activation. Phenylarsine oxide and N-ethyl maleimide induced phospholipase D activation is protein kinase C independent as it was not inhibited by compound-3 and bisindolylmaleimide, potent protein kinase C inhibitors. Tyrosine kinase inhibitor herbimycin A by itself activated PLD, but inhibited the phospholipase D activation by phenylarsine oxide and N-ethylmaleimide. These results suggest that oxidation of the cellular thiols activates phospholipase D independent of protein kinase C.     

Characteristics of a nitrogen-jet system in KUR-ISOL

The basic characteristics of a N₂-jet system coupled with a surface-ionization type ion source have been investigated at KUR-ISOL. The yields of transported activities and ionized ions have been measured under various conditions for both the He- and N₂-jets. The effects of N₂ gas upon the ionization and skimmer efficiency have been investigated. It was found that N₂ gas has almost no effect upon the ionization efficiency, but causes poorer skimmer efficiency than He gas owing to the large opening angle of aerosol particles at the outlet of a capillary. A mixture of He and N₂ gases was also tested.     

On a Population of Labile Synthesized Relaxation Oscillators

A labile synthesized relaxation oscillator (SRO), exhibiting rhythmic activity when excited by an appropriate stimulus, is proposed. Such an oscillator can be used to represent a stimulus-dependent (or labile) biological rhythm. A population of coupled labile SRO's is investigated and its generic equation is presented. The relationship between an input stimulus and an output rhythmic activity of an SRO is described in a computer-simulated example. Also, a tubular structure of nine coupled labile SRO's exhibiting apparently propagating bursts of rhythmic activity is simulated.     

Current mode biquadratic filter realizations employing operational amplifiers

New circuit configurations for realizing current mode biquadratic filter sections using operational amplifiers are presented. Each circuit uses a single operational amplifier and seven passive elements at most. The merits and demerits of the proposed realizations are discussed.     

Effect of methane concentration on physical properties of diamond-coated cemented carbide tool inserts obtained by hot-filament chemical vapour deposition

Diamond-coated tools can greatly improve the productivity of machining highly abrasive materials such as high silicon–aluminium alloys used in the automotive industry. Cemented-carbide diamond-coated tool inserts have not become an off-the-shelf product owing to several difficulties including insufficient adhesion of diamond to the substrate and questionable reproducibilty in their machining performance in the manufacturing. In order to overcome these difficulties, a better understanding of the effects of the chemical vapour deposition (CVD) conditions such as methane concentration, reactor pressure and substrate temperature is important. In this work, cemented tungsten carbide tool inserts with 6 wt% Co (WC–Co) were coated with diamond films deposited at five different methane concentrations (1–9 vol%). Here we present preliminary results of the effect of methane concentration variation on the following physical properties of the diamond coating: surface morphology; crystal structure; chemical quality; surface roughness; residual stress. The results indicate that the best physical properties of diamond-coated tool inserts using hot-filament CVD are achieved with diamond coatings deposited at methane concentrations ranging from 1 to 3%.     

Information processing in recovered depressed children and adolescents

Previous research into subjective probability estimates for negative events revealed that depressed children estimated events as equally likely to happen to themselves as to other children. In contrast, both controls and anxious children estimated that negative events were more likely to happen to others than to themselves. The present study followed up this finding by investigating the subjective probability judgements concerning future negative events generated by children and adolescents who have recovered from depression. Subjects generated probability estimates either for themselves or for other children for a range of negative events on a visual analogue scale. The results revealed that both recovered depressed and matched control groups estimated negative events as significantly more likely to happen to others than to themselves. It was also found that the recovered depressed subjects estimated that negative events were less likely overall, compared to the controls. These results are discussed in the context of the adult literature.     

Determining the optimum replacement policy for Holstein dairy herds in Iran

The objective of this study was to determine the optimum replacement policy for Holstein dairy herds in Iran using a dynamic programming model. Cows were described in terms of state variables that included milk production class, parity, pregnancy status, and month in milk with a 1-mo stage length. The objective function maximized the net present value of cows over a 15-yr planning horizon. Markov simulation was used to estimate expected herd dynamics under the optimal decision plan determined by dynamic programming. Stochastic elements included probabilities of pregnancy and abortion, production level, and involuntary culling. The optimum annual culling rate was estimated to be 31.4%, and cows had an expected herd life (time from first calving until culling) of 3.18 yr. High replacement cost and low carcass value resulted in only 2.87% voluntary culling (i.e., optimal model-based replacement). Assuming a heat detection rate of 0.4, cows averaged 2.8 services per lactation under the optimal policy. Sensitivity analyses were carried out to evaluate the effect of milk price, herd-average production, feed cost, heifer price, and carcass value on optimum replacement decisions. Herd-average production, replacement cost, and risk of involuntary culling were important factors affecting the optimal culling policy. Changes in the price of feed, calves, and milk and the probability of pregnancy had no considerable effect on the optimal policy considering the market situation in Iran during 2008.     

Effect of ultrasound- and pulsed electric field-assisted enzymatic treatment on the recovery and quality of sunflower oil

The aim of this study was to evaluate the effect of cavitation and electroporation on enzymolysis extraction of sunflower oil. The optimum extraction conditions during 2 h under enzyme-assisted extraction (EAE) with a maximum oil yield of ≈23.70 ± 0.11% were as follows: cellulase/pectinase ratio 2:1, enzyme concentration 2%, pH 4.5, liquid/solid ratio 6:1 ml/g, and extraction temperature 40°C. Under the optimized enzymatic conditions, the application of ultrasound- (250 W) and pulsed electric field- (1.2 kV/cm; 52.4 kJ/kg) assisted enzymatic extraction for 30 min significantly increased the oil extraction yield by 91.1% and 18.6%, respectively, as compared with EAE.     

Coupled particle swarm optimization method with genetic algorithm for the static–dynamic performance of the magneto-electro-elastic nanosystem

As a first attempt, Fourier series expansion (FSE), particle swarm optimization (PSO), and genetic algorithm (GA) methods are coupled for analysis of the static–dynamic performance and propagated waves in the magneto-electro-elastic (MEE) nanoplate. The FSE method is presented for solving the motion equations of the MEE nanoplate. For increasing the performance of genetic algorithms for solving the problem, the particle swarm optimization technique is added as an operator of the GA. Accuracy, convergence, and applicability of the proposed mixed approach are shown in the results section. Also, we prove that for obtaining the convergence results of the PSO and GA, we should consider more than 16 iterations. Finally, it is shown that if designers consider the presented algorithm in their model, the results of phase velocity of the nanosystem will be increased by 27%. A useful suggestion is that there is a region the same as a trapezium in which there are no effects from magnetic and electric potential of the MEE face sheet on the phase velocity of the smart nanoplate, and the region will be bigger by increasing the wavenumber.