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51.
Nursiati Mohamad Taridi Nazirah Abd Rani Azian Abd Latiff Wan Zurinah Wan Ngah Musalmah Mazlan 《Lipids》2014,49(9):855-869
Little is known about the effect of vitamin E on brain function. Therefore, in this study we evaluated the effect of tocotrienol rich fraction (TRF) on behavioral impairment and oxidative stress in aged rats. Thirty-six male Wistar rats (young: 3-months-old; aged: 21-months-old) were treated with either the control (olive oil) or TRF (200 mg/kg) for 3 months. Behavioral studies were performed using the open field test and Morris water maze (MWM) task. Blood was taken for assessment of DNA damage, plasma malondialdehyde (MDA) and vitamin E, and erythrocyte antioxidant enzyme activity. Brains were also collected to measure vitamin E levels. Results showed that aged rats exhibited reduced exploratory activity, enhanced anxiety and decreased spatial learning and memory compared with young rats. DNA damage and plasma MDA were increased, and vitamin E levels in plasma and brain were reduced in aged rats. Aged rats supplemented with TRF showed a markedly reduced level of anxiety, improved spatial learning and memory, reduced amount and severity of DNA damage, a reduced level of MDA, and increased levels of antioxidant enzyme activity and plasma/brain vitamin E compared with age-matched controls. In conclusion, TRF supplementation reverses spatial learning and memory decline and decreases oxidative stress in aged rats. 相似文献
52.
This article presents a new nonlinear classifier by arranging linear classifiers in a tree structure. The proposed classifier, called the direct fractional-step linear discriminant (DF-LDA) tree, adopts a tree structure containing a DF-LDA at each node. The structure of the tree classifier evolves as the training proceeds, so there is no need to decide any parameters as a priori. Due to the many DF-LDAs arranged in the tree structure, classification performance of the proposed classifier is improved over single-shot DF-LDA. The proposed DF-LDA tree is tested on various synthetic and real datasets. Experimental results show that the proposed classifier leads to very satisfactory results in terms of classification accuracy. 相似文献
53.
Normal modes of vibration of syndiotactic polypropylene (sPP) and their dispersion are obtained in the reduced zone scheme for helical form I having the conformational sequence (t2g2) using Urey-Bradley force field and Wilson's GF matrix method as modified by Higgs. Optically active frequencies corresponding to the zone center and zone boundary are assigned and characteristic features of the dispersion curves are discussed. In general the dispersion in the helical form is less as compared to the planar form. Heat capacity has been calculated via density-of-states using Debye relation in the temperature range 10-460 K and compared with the experimental measurements. 相似文献
54.
The oxidation of alcohols to carbonyls was investigated by an efficient catalyst system comprising of Fe(III)–Schiff base–triphenylphosphine complex. The complex chloroN-(2-mercaptophenyl)salicylideneiminebis(triphenylphosphine)iron(III) showed higher activity for oxidation of various alcohols under relatively mild conditions. 相似文献
55.
R. Subramanian Christoph A. Roden Poonam Boparai Tami C. Bond 《Aerosol science and technology》2013,47(6):630-637
Particulate emissions from low-temperature biomass burning are dominated by organic matter. Here, we show that such emissions have a liquid, bead-like appearance when collected on fibrous filters, and the number of these beads are far less than expected for solid spherical particles. These shapes are in line with published drop-on-fiber theories for liquids entrained on filaments. A smoldering pine sample is yellowish, with organic carbon over 99% of the total carbon, and chars substantially in thermal-optical analysis (TOA), indicating that such liquid organic particles could affect both absorption measurements and TOA of such samples. Similar colored samples collected in the field from rice-straw burning and cook stove emissions also show a similar liquid appearance. 相似文献
56.
In natural rubber/high styrene resin microcellular sheets, part of natural rubber was replaced by latex reclaim prepared from waste latex products. The mechanical properties and cell structure of the products were evaluated. It was found that latex reclaim can replace about 30% of natural rubber without affecting the technical properties of the microcellular sheets. 相似文献
57.
T. Prathap Kumar K. N. Prasanna Rani M. Mallikarjun V. V. Basava Rao 《Chemical Engineering Communications》2013,200(4):572-589
Levulinic acid, a carboxylic acid containing a ketone structure, can be used as an acidulant in foods and beverages. Reactive extraction is a promising alternative for the recovery of carboxylic acids from aqueous streams. The design of an amine extraction process requires kinetic data for the acid-amine + solvent system used. In this study, equilibrium and kinetic data on the extraction of levulinic acid from aqueous solutions using tri-n-octylamine (TOA) in 1-octanol have been determined. The mass transfer coefficients of levulinic acid, TOA, and 2:1 levulinic acid-amine complex in 1-octanol were calculated from the acetic acid mass transfer coefficient, which was determined by measuring its fluxes of simple diffusion from kerosene to water. Based on the Hatta number and the criterion given by Doraiswamy and Sharma, the reaction regime has been found to be instantaneous reaction regime occurring at the interface on the organic phase side. An extraction model comprising equilibrium complexation constant w.r.t 2:1 levulinic acid-TOA complex formation, KE2i (14.794 (m3 kmol?1)2), and complex mass transfer coefficient, kB2A (2.193 × 10?6 m s?1), has been developed. 相似文献
58.
Gagan Kumar Ritu Rani Sucheta Sharma Khalid M. Batoo M. Singh 《Ceramics International》2013,39(5):4813-4818
Cobalt substituted Mg–Mn nanoferrites with formulae Mg0.9Mn0.1CoxFe2?xO4, x=0.0, 0.1, 0.2 and 0.3, have been synthesized for the first time by the solution combustion technique. The effects of Co2+ ions on the dc resistivity, dielectric constant and dielectric loss tangent of Mg–Mn nanoferrites at room temperature are presented in this paper. X-ray diffraction confirmed the formation of a single phase spinel structure. Particle size was found to increase, 20.9–23.9 nm, with increasing Co2+ concentration. The dc resistivity was increased by two order of magnitude with substitution of Co2+ ions while the dielectric constant was found to be decreasing with the increasing concentration of cobalt ions. The value of dc resistivity obtained for Mg0.9Mn0.1Fe2O4 nanoferrite in our work is greater than the value obtained for the same composition prepared by the conventional ceramic technique. Further, the dielectric constant and dielectric loss tangent were observed to be decreasing with the increase in frequency. 相似文献
59.
Suman Rani Neetu Ahlawat R. Punia Kanta Maan Sangwan Sunita Rani 《Ceramics International》2018,44(6):5996-6001
In this work, Sr and Zn co-doped calcium copper titanate having nominal formula Ca0.90Sr0.10Cu3Ti3.95Zn0.05O12 has been synthesized and systematically studied for structure, dielectric and electrical properties. The phase purity of the prepared composition has been confirmed by X-ray diffraction (XRD) pattern and various structural parameters are presented here with Rietveld refinement data. The Scanning electron microscopy (SEM) image revealed the presence of homogeneous fine-grained microstructure investigated in the prepared ceramic. The impedance data well fitted with 2 R-CPE model confirmed the non-ideality of the system. Dielectric studies have shown the existence of two relaxation processes in low and high frequency domains. Low frequency dielectric response proposed as a combination of Maxwell-Wagner relaxation and intrinsic defect (Vo++) while high frequency behavior has been interpreted in terms of polaronic relaxation caused by hopping process of an electron between Ti3+ and Ti4+ states. The frequency dependent behavior of conductivity has been well fitted to Dong’s model and interpreted in term of Overlapping Large Polaron Tunneling (OLPT) mechanism. The various parameters; relaxation angular frequency (ω1) of Debye process, ionic hopping frequency (ω2), dc conductivity (σo), cole- cole parameter (α) and frequency exponent (s) have been determined by Dong’s Model fitting. 相似文献
60.
Rashmi Rani Seema Sharma Radheshyam Rai Andrei L. Kholkin 《Materials Research Bulletin》2012,47(2):381-386
Ceramic samples of [Na0.5K0.5]1 ? x(Li)x(Sb)x(Nb)1 ? xO3 (NKNLS) (x = 0.04–0.06) were prepared by high temperature solid-state reaction method. X-ray diffraction analysis of the powder samples suggests the formation of a single-phase material with transformation from orthorhombic to tetragonal crystal structure with increase in Sb content. Dielectric studies show a diffuse phase transition about 100 °C and another phase ferroelectric–paraelectric transition at 330 °C. Polarization vs. electric field (P–E) hysteresis studies show maximum remanent polarization (Pr ~ 0.66 C m?2) for composition x = 0.05. AC conductivity in the compound increases with increase in temperature which may be attributed due to oxygen vacancies and show negative temperature coefficient of resistance (NTCR) effect. 相似文献