Analysis of Fatty Acid, and Lipoprotein, Metabolism by GC and HPLC: Effect of Low-Density Lipoprotein Apheresis

 Blood samples from 5 hyperlipidemic patients on chronic treatment with low-density lipoprotein (LDL) – apheresis were analysed for lipids and fatty acids in serum, lipoprotein fractions and erythrocyte membrane by capillary gas chromatography (GC), reversed-phase high-performance liquid chromatography (LC), spectrofluorometry and spectrophotometry. LDL-apheresis has been associated with significant changes of fatty acids metabolism in relation to triglyceride-rich lipoproteins. Oleic acid may exert its hypotriglyceridemic effect via VLDL, IDL, LDL and HDL fractions. Polyunsaturated fatty acids, associated with triglyceride metabolism via IDL or VLDL, are linoleic, gamma-linolenic and docosahexaenoic fatty acids. Received November 25, 1999. Revision September 5, 2000.     

Analysis of functionally graded thick truncated cone with finite length under hydrostatic internal pressure

Finite Element Method based on Rayleigh–Ritz energy formulation is applied to obtain the elastic behavior of functionally graded thick truncated cone. The cone has finite length, and it is subjected to axisymmetric hydrostatic internal pressure. The inner surface of the cone is pure ceramic and the outer surface is pure metal, and the material composition varying continuously along its thickness. Using this method, the effects of semi-vertex angle of the cone and the power law exponent on distribution of different types of displacements and stresses are considered.     

On the Formation of TiO<Subscript>2</Subscript> Nanoparticles Via Submerged Arc Discharge Technique: Synthesis,Characterization and Photocatalytic Properties

We report a simple and inexpensive synthesis route of TiO₂ nanoparticles using electrical arc discharge between titanium electrodes in oxygen bubbled deionized (DI) water followed by heat treatment. The resulting nanoparticles were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD patterns demonstrate formation of TiO₂ phase in oxygen bubbled water after heat treatment and dominance of rutile to anatase phase. The size and morphology of TiO₂ nanoparticles were studied using different arc currents as a crucial parameter in properties of final product. Microscopic studies reveal nanosize spherical particles. DLS results indicate that at 20 A arc current, the size of the particles is about 37 nm and increases to 59 nm by increasing the arc current up to 40 A. Photodegradation of Rhodamine B (Rh. B) as a standard pollution shows that heat treated samples in oxygen bubbled water for 2 h at 500 °C, have more photocatalytic activity due to enhancement in crystallinity.     

Development of Abraham model correlations for predicting enthalpies of solvation of nonionic solutes dissolved in formamide

Experimental enthalpy of solution data for 81 solutes dissolved in formamide have been compiled from the published literature and converted to enthalpies of solvation data using standard thermodynamic relationships. Abraham model correlations were derived from the compiled enthalpy of solvation data. The derived mathematical equations describe the observed experimental to within overall standard deviations of 2.3 kJ mol^?1. A principal component analysis based on the calculated equation coefficients, and the coefficients for water and 23 organic solvents previously determined, shows that formamide is both a hydrogen-bond acid and a hydrogen-bond base. Of the solvents that we have studied thus far, formamide is the closest to water in terms of enthalpies of solvation of dissolved solutes.     

The phototoxicity of aged human retinal melanosomes

The purpose of this study was to determine whether an age-related increase in photoreactivity of human retinal melanosomes (MS) can cause phototoxicity to retinal pigment epithelium (RPE) cells. MS were isolated post mortem from young (20-30 years, young human melanosomes [YHMs]) and old (60-90 years, old human melanosomes [OHMs]) human eyes and from young bovine eyes (bovine melanosomes [BMs]). Confluent cultured ARPE-19 cells were fed equivalent numbers of OHMs or BMs and accumulated similar amounts of melanin as determined by electron paramagnetic resonance assay. Cells with and without MS were either maintained in the dark or exposed to blue light for up to 96 h and assessed for alterations in cell morphology, cell viability and lysosomal integrity. Incubation of cells in dark in the presence of internalized MS or irradiation of cells with blue light in the absence or presence of BMs did not significantly affect cell viability. However, exposures to blue light in the presence of OHMs resulted in abnormal cell morphology, up to approximately 75% decrease in mitochondrial activity, loss of lysosomal pH and cell death. OHMs contained significantly less melanin than YHMs, supporting the hypothesis that melanin undergoes degradation during RPE aging. Our results demonstrate that aged MS can be phototoxic to human RPE cells and support a contributing role of MS in RPE aging and in the pathogenesis of age-related macular degeneration.     

Multiple Quantum Coherences (MQ) NMR and Entanglement Dynamics in the Mixed-Three-Spin XXX Heisenberg Model with Single-Ion Anisotropy

We analytically investigate Multiple Quantum (MQ) NMR dynamics in a mixed-three-spin (1/2,1,1/2) system with XXX Heisenberg model at the front of an external homogeneous magnetic field B. A single-ion anisotropy property ζ is considered for the spin-1. The intensities dependence of MQ NMR coherences on their orders (zeroth and second orders) for two pairs of spins (1,1/2) and (1/2,1/2) of the favorite tripartite system are obtained. It is also investigated dynamics of the pairwise quantum entanglement for the bipartite (sub)systems (1,1/2) and (1/2,1/2) permanently coupled by, respectively, coupling constants J₁ and J₂, by means of concurrence and fidelity. Then, some straightforward comparisons are done between these quantities and the intensities of MQ NMR coherences and ultimately some interesting results are reported. We also show that the time evolution of MQ coherences based on the reduced density matrix of the pair spins (1,1/2) is closely connected with the dynamics of the pairwise entanglement. Finally, we prove that one can introduce MQ coherence of the zeroth order corresponds to the pair spins (1,1/2) as an entanglement witness at some special time intervals.     

Microwave Assisted Amine Formylation by a Heterogeneous HCO2H/SiO2 System

A simple, fast and efficient procedure has been developed for the synthesis of formamides by treating a silica gel/formic acid mixture with amines under microwave irradiation.     

Magnetic Properties of an Antiferromagnetic Spin-1/2 XYZ Model in the Presence of Different Magnetic Fields: Finite-Size Effects of Inhomogeneity Property*

Magnetic and thermodynamic properties of the anisotropic XYZ spin-1/2 finite chain under both homogeneous and inhomogeneous magnetic fields are theoretically studied at low temperature. Using exact diagonalization method (ED), we study the magnetization, magnetic susceptibility, and specific heat of the model characterized in terms of the finite correlation length in the presence of three different magnetic fields including longitudinal, transverse, and transverse staggered magnetic fields. The magnetization, susceptibility, and the specific heat of the model are investigated under two conditions separately: (i) When the model is putted in the presence of homogeneous magnetic fields. (ii) When finite inhomogeneities are considered for all applied magnetic fields in the Hamiltonian. We show that for the finite-size XYZ chains at low temperature, the evident magnetization plateaus gradually convert to their counterpart quasi-plateaus when the transverse magnetic field increases. Moreover, the influence of the transverse and staggered transverse magnetic fields, and their corresponding inhomogeneities on the magnetization process, magnetic susceptibility, and specific heat are reported in detail. Our exact results illustrate that by altering the inhomogeneity parameters, magnetization plateaus gradually convert to their counterpart quasi-plateaus. The specific heat manifests Schottky-type maximum, double-peak, and triple-peak, as well as, transformation between them by varying considered inhomogeneity parameters in the Hamiltonian.     

Transferring information through a mixed-five-spin chain channel

We initially introduce one-dimensional mixed-five-spin chain with Ising-XY model which includes mixture of spins-1/2 and spins-1. Here, it is considered that nearest spins(1, 1/2) have Ising-type interaction and nearest spins(1/2, 1/2)have both XY-type and Dzyaloshinskii–Moriya(DM) interactions together. Nearest spins(1, 1) have X X Heisenberg interaction. This system is in the vicinity of an external homogeneous magnetic field B in thermal equilibrium state. We promote the quantum information transmitting protocol verified for a normal spin chain with simple model(refer to Rossini D, Giovannetti V and Fazio R 2007 Int. J. Quantum Infor. 5 439)(widely in reference: Giovannetti V and Fazio R 2005 Phys. Rev. A 71 032314) by means of considering the suggested mixed-five-spin chain as a quantum communication channel for transmitting both qubits and qutrits ideally. Hence, we investigate some useful quantities such as quantum capacity and quantum information transmission rate for the system. Finally, we conclude that, when the DM interaction between spins(1/2, 1/2) increases the system is a more ideal channel for transmitting information.     

Entanglement detection in the mixed-spin Ising–XY model

In the present work, we initially verify anisotropy effect on the heat capacity of a mixed-three-spin(1/2,1,1/2) system(where spins(1/2,1/2) have XY interaction and spins(1,1/2) have Ising interaction together) at finite temperatures, then,the pairwise entanglement for spins(1/2,1/2), by means of negativity(as a measure of entanglement) as a function of the temperature T, homogeneous magnetic field B, and anisotropy parameter γ is investigated. In addition, we show that one can find magnetic phase transition points for the spins(1/2,1/2) at finite temperatures and understand properly their behavior with respect to the magnetic field and the anisotropy parameter, via the negativity function. An interval of the magnetic field from the negativity diagram of the spins(1/2,1/2) is presented in which quantum phase transition occurs for the tripartite mixed-three-spin system. Finally, some new interesting entanglement witnesses are introduced by using non-degenerate perturbation theory for the mixed-three-spin system.