199 research outputs found

    Determination of the Protonation Constants of Some 4-(Substituted benzylamino)-4,5-dihydro- 1H-1,2,4-triazol-5-ones by the Potentiometric Method in Ethanol–Water Mixtures

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    To gain more information about the effect of solvent on 4,5-dihydro-1H-1,2,4-triazol-5-ones, the stoichiometric protonation constants of thirteen triazoles in ethanol–water mixtures were determined at an ionic strength of 0.10MNaCl and at 25.0±0.1 °C under nitrogen atmosphere. A potentiometric method was used and the  calculation was carried out using the PKAS computer program. The correspondingpKa values of these triazoles were determined in ethanol–water mixtures. Thus, the effects of solvent and molecular structure upon acidity were investigated. The logarithm of the protonation constants of the title 4,5-dihydro- 1H-1,2,4-triazol-5-ones decreased linearly with increasing ethanol content, but the values determined with 80% ethanol did not follow this linear trend. The variation of these constants is discussed on the basis of specific solute–solvent  interactions.KEYWORDS: Potentiometry, protonation constants, solvent effect, triazoles

    Investigation of temporal bone asymmetry in cases with unilateral tinnitus: morphometric and multicentric clinical study

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    The aim of this multicentric study was to compare the anatomical structures of temporal bone in patients with unilateral tinnitus with their healthy ears. We also aimed at evaluating whether age and gender-related asymmetrical changes occur in temporal bones or not. Fifty two ears of 26 patients who had unilateral tinnitus were included into the retrospective study. The patients who had subjective nonpulsatile tinnitus and who previously had temporal computed tomography according to their file records were accepted to study. Temporal CT scans and audiometric results of patients were examined retrospectively. Middle ear volume, diameter of internal acoustic meats and diameter of jugular bulb were evaluated by both anatomist and radiologist, interobserverly. Internal acoustic meats and jugular bulb were found larger in the ears that had tinnitus than healthy ears; however, there was no statistically significance. The stereological morphometrical study of temporal bone asymmetry in humans correlate with sex is of importance for both otolarygologs and anatomists. These results will contribute to data on middle ear volume, internal acustic meats and jugular bulb sizes

    Pyramiding multiple genes for resistance to PVY, TSWV and PMMoV in pepper using molecular markers

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    Pepper (Capsicum annuum L.) is one of the most important vegetables cultivated worldwide. Many pests and pathogens cause economic yield losses in pepper. Potato virus Y (PVY), Tomato spotted wilt virus (TSWV) and Pepper mild mottle virus (PMMoV) are considered among the most destructive viruses affecting pepper in the world. Because chemical treatments have limited success for managing PVY, TSWV and PMMoV, resistant varieties are considered to be the most effective means of controlling these viruses. In this study, resistance genes to these viruses were successfully transferred to the superior sweet Charleston pepper line 'Y-CAR' using molecular markers and biological assays. As a result, a new line which is resistant to PVY, TSWV and PMMoV was developed. The results also showed the applicability of a pyramiding strategy for breeding multiple virus resistance in pepper. © Verlag Eugen Ulmer KG, Stuttgart.Scientific and Technological Research Council of Turkey, TEYDEP foundation (3080171

    Structural and Magnetic Properties of La₀.₇Sr₀.₃Mn₁₋ₓNiₓO₃ (x ≤ 0.4)

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    We have studied the structural and magnetic properties of La0.7Sr0.3Mn1-xNixO3 (x = 0.05, 0.1, 0.20, 0.30, and 0.40) perovskites using x-ray and neutron diffraction and magnetic measurements. Our data consist of neutron (γ = 1.479Å) and x-ray (γ = 1.5481Å; Cu Kα) powder diffraction and magnetization measurements. We previously suggested these systems transition from ferromagnetic to antiferromagnetic ordering with the intermediate concentrations containing coexisting domains of ferromagnetically and antiferromagnetically ordered states. Upon further detailed examination, we find that the samples are homogeneous and that neutron data can be fitted to a single long-range magnetically ordered state. The compositional dependent changes are driven by a shift in the dominant near neighbor interaction from ferromagnetic to antiferromagnetic. In the intermediate compositions, peaks previously identified as due to antiferromagnetic ordering, in fact arise from charge ordering; the system remains in a ferromagnetic state where the Ni moments are antiparallel to the Mn moments. This interpretation supersedes multiphase and spin glass models for these complex systems

    Effect of DMSO on the mechanical and structural properties of model and biological membranes

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    This is the final version. Available from Elsevier via the DOI in this recordDimethyl sulfoxide (DMSO) is widely used in a number of biological and biotechnological applications, mainly because of its effects on the cell plasma membrane, but the molecular origins of this action are yet to be fully clarified. In this work, we used two- and three-component synthetic membranes (liposomes) and the plasma membrane of human erythrocytes to investigate the effect of DMSO when added to the membrane-solvating environment. Fourier transform infrared spectroscopy and thermal fluctuation spectroscopy revealed significant differences in the response of the two types of liposome systems to DMSO in terms of the bilayer thermotropic behavior, available free volume of the bilayer, its excess surface area, and bending elasticity. DMSO also alters the mechanical properties of the erythrocyte membrane in a concentration-dependent manner and is capable of increasing membrane permeability to ATP at even relatively low concentrations (3% v/v and above). Taken in its entirety, these results show that DMSO is likely to have a differential effect on heterogeneous biological membranes, depending on their local composition and structure, and could affect membrane-hosted biological functions.Engineering and Physical Sciences Research Council (EPSRC

    Analysis of wavelet controller for robustness in electronic differential of electric vehicles: an investigation and numerical developments

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    In road transportation systems, differential plays an important role in preventing the vehicle from slipping on curved tracks. In practice, mechanical differentials are used, but they are bulky because of their increased weight. Moreover, they are not suitable for electric vehicles, especially those employing separate drives for both rear wheels. The electronic differential constitutes recent technological advances in electric vehicle design, enabling better stability and control of a vehicle on curved roads. This article articulates the modeling and simulation of an electronic differential employing a novel wavelet transform controller for two brushless DC motors ensuring drive in two right and left back driving wheels. Further, the proposed work uses a discrete wavelet transform controller to decompose the error between actual and command speed provided by the electronic differential based on throttle and steering angle as the input into frequency components. By scaling these frequency components by their respective gains, the obtained control signal is actually given as input to the motor. To verify the proposal, a set of designed strategies were carried out: a vehicle on a straight road, turning right and turning left. Numerical simulation test results of the controllers are presented and compared for robust performance and stability

    Development of Molecular Markers Tightly Linked to Pvr4 Gene in Pepper Using Next-Generation Sequencing

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    It is imperative to identify highly polymorphic and tightly linked markers of a known trait for molecular marker-assisted selection. Potyvirus resistance 4 (Pvr4) locus in pepper confers resistance to three pathotypes of potato virus Y and to pepper mottle virus. We describe the use of next-generation sequencing technology to generate molecular markers tightly linked to Pvr4. Initially, comparative genomics was carried out, and a syntenic region of tomato on chromosome ten was used to generate PCR-based markers and map Pvr4. Subsequently, the genomic sequence of pepper was used, and more than 5000 single-nucleotide variants (SNVs) were identified within the interval. In addition, we identified nucleotide binding site–leucine-rich repeat-type disease resistance genes within the interval. Several of these SNVs were converted to molecular markers desirable for large-scale molecular breeding programmes

    An integrated map of structural variation in 2,504 human genomes

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    Structural variants are implicated in numerous diseases and make up the majority of varying nucleotides among human genomes. Here we describe an integrated set of eight structural variant classes comprising both balanced and unbalanced variants, which we constructed using short-read DNA sequencing data and statistically phased onto haplotype blocks in 26 human populations. Analysing this set, we identify numerous gene-intersecting structural variants exhibiting population stratification and describe naturally occurring homozygous gene knockouts that suggest the dispensability of a variety of human genes. We demonstrate that structural variants are enriched on haplotypes identified by genome-wide association studies and exhibit enrichment for expression quantitative trait loci. Additionally, we uncover appreciable levels of structural variant complexity at different scales, including genic loci subject to clusters of repeated rearrangement and complex structural variants with multiple breakpoints likely to have formed through individual mutational events. Our catalogue will enhance future studies into structural variant demography, functional impact and disease association. © 2015 Macmillan Publishers Limited. All rights reserved
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