The Effect of Selenium Supplementation on the NMR Proton Relaxation Time T1 in Plasma

Selenium has been identified as an essential dietary trace e1ementQ)which is a component of glutathione peroxidase (GSH-Px)(₂)and a cytochrome C-like protein(₃), The enzyme,the four subunits of which each contain one atom of selenium in the form of selenocysteine, the selenium containing active centre being amenable to chemical modification, catalyses the reduction of H,O,and organic hydroperoxides to water.In this way GSH-Px plays an important role in the protection of the cell from oxidative stresses such as the superoxide anion,organic hydroperoxides and H₂O₂     

Delayed resonator with acceleration feedback – Complete stability analysis by spectral methods and vibration absorber design

This paper deals with the problem of active vibration suppression using the concept of delayed resonator (DR) absorber with acceleration feedback. A complete dynamic analysis of DR and its coupling with a single degree of freedom mechanical system are performed. Due to the presence of a delay in the acceleration feedback, the dynamics of the resonator itself, as well as the dynamics of combined system are of ‘neutral’ character. On this system, spectral methods are applied to perform a complete stability analysis. Particularly, the method of cluster treatment of characteristic roots is used to determine stability boundaries in the space of the resonator parameters. Based on this analysis, a methodology to select the resonator parameters is proposed in order to guarantee desirable suppression characteristics and to provide safe stability margins. An example case study is included to demonstrate these analytical results.     

A modified Gaussian moment closure method for nonlinear stochastic differential equations

Parametric excitation of a nonlinear physical pendulum by modulation of its moment of inertia is analyzed in terms of physics as an example of the suggested approach. The modulation is provided by a redistribution of auxiliary masses. The system is investigated both analytically and with the help of computer simulations. The threshold and other characteristics of parametric resonance are found and discussed in detail. The role of nonlinear properties of the physical system in restricting the resonant swinging is emphasized. Phase locking between the drive and oscillations of the pendulum and the phenomenon of parametric autoresonance are investigated. The boundaries of parametric instability are determined as functions of the modulation depth and the quality factor. The feedback providing active optimal control of amplification and attenuation of oscillations is analyzed. An effective method of suppressing undesirable rotary oscillations of suspended constructions is suggested.     

Regional Differences in Rice Hulls Supply for Bioethanol Production

Agricultural by-products are becoming an attractive substrate for bioethanol production. The aim of this study was to evaluate the effects of regional differences in the rice hulls using Escherichia coli KO11 for bioethanol production. The rice hulls coded Edirne were obtained from Thrace Region, and the rice hulls coded Izmir were obtained from Aegean Region in Turkey. Rice hulls were treated by dilute acid before using them as substrates. The cells were incubated on an orbital shaker at 160 rpm under 30 °C during 96 h of the fermentation period. It was found that the maximum yield of ethanol from sugar (0.44 g ethanol/g reducing sugar) was obtained with the substrate C/N ratio of 29.16 in Izmir medium. The main difference was the dominant carbon source available as a substrate. It was detected that glucose concentration was about 2.5 times higher in Izmir medium, whereas xylose concentration was about two times higher in Edirne medium. The different results obtained with rice hulls from different origins could depend on the type of paddy as well as different cultivation conditions. These findings provide a valuable indicator for identifying suitable agricultural waste materials to be used as substrates for bioethanol production.     

Semi-continuous Cultivation of Haematococcus pluvialis for Commercial Production

The objectives of the present study on the growth of Haematococcus pluvialis were to indicate the effects of a long-term semi-continuous cultivation, sterilization, carbon dioxide, and different culture media by using artesian well water. This investigation was an enterprise in order to commercialize the production economically. When the effect of CO₂ was investigated in basal culture medium, the influence of sterilization was also researched in Rudic’s culture medium in vertical panel-type photobioreactors for 31 days of semi-continuous cultivation. The maximum cell concentration of 10.55?×?10⁵ cells ml^?1, which corresponds to the growth rate of 0.271 day^?1 with the areal productivity of 3.531 g m^?2 day^?1, was found in non-sterilized RM medium on the 24th day of the third run of semi-continuous cultivation at a renewal rate of 50% in a vertical panel-type photobioreactor.     

Lattice Boltzmann simulation of non-Newtonian flows past confined cylinders

A second-order lattice Boltzmann algorithm is used for Power-Law non-Newtonian flow simulation. The shear dependent behavior of the fluid is implemented through calculating the shear locally from the lattice distribution functions. A step by step verification procedure is taken to ensure the accuracy and the physical correctness of the numerical simulation. The flow past a series of tandem arrangement of two cylinders is computed in a confined domain. The effects of Reynolds number, the Power-Law index, and the distance between two cylinders on both the flow field and the drag coefficients of the cylinders are examined in detail.     

Electronic structure and correlations of vitamin B<Subscript>12</Subscript> studied within the Haldane-Anderson impurity model

We study the electronic structure and correlations of vitamin B₁₂ (cyanocobalamine) by using theframework of the multi-orbital single-impurity Haldane-Anderson model of atransition-metal impurity in a semiconductor host. The parameters of the effectiveHaldane-Anderson model are obtained within the Hartree-Fock (HF) approximation. Thequantum Monte Carlo (QMC) technique is then used to calculate the one-electron andmagnetic correlation functions of this effective model. We observe that new states forminside the semiconductor gap found by HF due to the intra-orbital Coulomb interaction atthe impurity 3d orbitals. In particular, the lowest unoccupiedstates correspond to an impurity bound state, which consists of states from mainly the CNaxial ligand and the corrin ring as well as the Co e_g-like orbitals. We alsoobserve that the Co?(3d) orbitals can develop antiferromagneticcorrelations with the surrounding atoms depending on the filling of the impurity boundstates. In addition, we make comparisons of the HF+QMC data with the density functionaltheory calculations. We also discuss the photoabsorption spectrum of cyanocobalamine.     

A high-order Monte Carlo algorithm for the direct simulation of Boltzmann equation

A high-order algorithm of the direct simulation Monte Carlo (DSMC) method, H-DSMC, has been developed to simulate rarefied flow regimes. The mth order Taylor series expansion has been employed to obtain a more generalized form of the time discretization for the collision part of Boltzmann equation. In the purposed algorithm, the higher order collision terms are introduced as well as higher order terms in the time step of the probabilistic coefficients. These newly implemented higher order terms improve the accuracy and efficiency of the solution and enhance the convergence rate quite significantly. Comparison between results of the classic DSMC method and the H-DSMC method shows the promising performance of the introduced technique.     

Symmetric space σ-model dynamics: Internal metric formalism

For the symmetric space sigma model in the internal metric formalism we explicitly construct the Lagrangian in terms of the axions and the dilatons of the solvable Lie algebra gauge and then we exactly derive the axion–dilaton field equations.     

Zeolite-catalyzed synthesis of pyrazolo[1,2-<Emphasis Type="Italic">a</Emphasis>][1,2,4]triazole-1,3-dione derivatives as anti-breast cancer agents

A series of pyrazolo[1,2-a][1,2,4]triazole-1,3-dione derivatives were synthesized under the catalytic effect of Natrolite zeolite, and their cytotoxic effects on three human breast cancer cell lines viz. breast cancer (BT-474), triple negative breast cancer (MDA-MB 231), and breast carcinoma (MCF-7) were explored using MTT assay. Apoptotic effects of the compounds were investigated by western blot analysis on the caspase-3 protein. Moreover, we examined the level of reactive oxygen species in all three cell lines. The most promising compound, 7-Amino-1,3-dioxo-5-(4-nitrophenyl)-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]triazole-6-carbonitrile (4c), showed high levels of cytotoxicity against all cell lines with IC₅₀ values of 2.3, 2.5 and 3 μg/ml, respectively.