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101.
G. YildirimM. Akdogan S.P. AltintasM. Erdem C. Terzioglu A. Varilci 《Physica B: Condensed Matter》2011,406(10):1853-1857
We measured resistivity and transport critical current density, Jc, as a function of DC magnetic field and the angle (?) between the surface of the film and the magnetic field on ex-situ annealed, c-axis oriented Bi-2223 thin films fabricated by DC sputtering method. Irreversibility field (μ0Hirr) and upper critical field (μ0Hc2) were determined from the resistivity versus the applied magnetic field graph. It is observed that critical temperature (Tc), μ0Hirr,μ0Hc2 and Jc of the films strongly depend on the direction and strength of the field. While Tc of the film without magnetic field is observed to be about 102 K, it is found to decrease to 90 K (85 K) for the applied field perpendicular (parallel) to c-axis of the film. Not only were μ0Hirr(0) and μ0Hc2(0) values determined from the μ0Hirr and μ0Hc2 versus temperature graphs, respectively, but also penetration depths and coherence lengths were interpreted. Anisotropy of the film was also discussed by means of the change of irreversibility as a function of angle. Moreover at 4.2 K, Jc was observed to be 3000 A/cm2 at zero field; however, it was found to abruptly decrease to 1982 (1 1 2 0) A/cm2 under low magnetic field at ?=0° (?=90°), which indicates that anisotropic Jc behavior of the film is intrinsic. Furthermore, we provided a theoretical analysis of the obtained results in the framework of intrinsic pinning theory of superconductors. Microstructural properties of the produced films were also reinvestigated by X-ray diffractometer (XRD) and scanning electron microscopy (SEM) measurements. XRD patterns indicate that the films are c-axis oriented based on the prominent (0 0 l) peaks. SEM images show needle-like grain structures dominate the surface morphology of the films. 相似文献
102.
Muti M Erdem A Caliskan A Sınag A Yumak T 《Colloids and surfaces. B, Biointerfaces》2011,86(1):154-157
The effect of the SnO(2) nanoparticles (SNPs) on the behaviour of voltammetric carbon paste electrodes were studied for possible use of this material in biosensor development. The electrochemical behaviour of SNP modified carbon paste electrodes (CPE) was first investigated by using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. The performance of the SNP modified electrodes were compared to those of unmodified ones and the parameters affecting the response of the modified electrode were optimized. The SNP modified electrodes were then tested for the electrochemical sensing of DNA purine base adenine to explore their further development in biosensor applications. 相似文献
103.
Ozlem Erdas Cenk A. Andac A. Selen Gurkan‐Alp Ferda Nur Alpaslan Erdem Buyukbingol 《Journal of Chemometrics》2013,27(6):155-164
Analyses of known protein–ligand interactions play an important role in designing novel and efficient drugs, contributing to drug discovery and development. Recently, machine learning methods have proven useful in the design of novel drugs, which utilize intelligent techniques to predict the outcome of unknown protein–ligand interactions by learning from the physical and geometrical properties of known protein–ligand interactions. The aim of this study is to work through a specific example of a novel computational method, namely compressed images for affinity prediction (CIFAP), in which binding affinities for structurally related ligands in complexes with human checkpoint kinase 1 (CHK1) are predicted. The CIFAP algorithm presented here relates published pIC 50 values of 57 compounds, derived from a thienopyridine pharmacophore, in complexes with CHK1 to their two‐dimensional (2D) electrostatic potential images compressed in orthogonal dimensions. Patterns obtained from the 2D images are then used as inputs in regression and learning algorithms such as support vector regression (SVR) and adaptive neuro‐fuzzy inference system (ANFIS) methods to validate the experimental pIC 50 values. This study revealed that the 2D image pixels in the vicinity of bound ligand surfaces provide more relevant information to make correlations with the empirical pIC 50 values. As compared with ANFIS, SVR gave rise to the lowest root mean square errors and the greatest correlations, suggesting that SVR could be a plausible choice of machine learning methods in predicting binding affinities by CIFAP. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
104.
Valentin Dybbert Samuel Matthias Fehr Florian Klein Achim Schaadt Anke Hoffmann Elias Frei Emre Erdem Thilo Ludwig Harald Hillebrecht Ingo Krossing 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(37):13069-13073
The influence of a mild difluorine treatment on Cu/ZnO precatalysts for methanol synthesis was investigated. It led to the incorporation of 1.2…1.3±0.1 wt % fluoride into the material. Fluorination considerably increased the amount of ZnOx related defect sites on the catalysts and significantly increased the space‐time yields. Although the apparent activation energy EA,app for methanol formation from CO2 and H2 was almost unchanged, the EA,app for the reverse water‐gas shift (rWGS) reaction increased considerably. Overall, fluorination led to a significant gain in methanol selectivity and productivity. Apparently, also the quantity of active sites increased. 相似文献
105.
Guleli Muge Erdem Safiye S. Ocal Nuket Erden Ihsan Sari Ozlem 《Research on Chemical Intermediates》2019,45(4):2119-2134
Research on Chemical Intermediates - An efficient and general method for the synthesis of substituted 3,4-dimethylisoxazolo[5,4-b]pyridine-5-carboxamide and benzo[b][1,8]naphthyridine-3-carboxamide... 相似文献
106.
Hároníková Lucia Špaček Jan Plucnara Medard Horáková Petra Pivoňková Hana Havran Luděk Erdem Arzum Fojta Miroslav 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):849-855
Monatshefte für Chemie - Chemical Monthly - In this report, we present a simple electrochemical detection protocol for the detection of specific PCR-amplified DNA fragments, based on... 相似文献
107.
108.
Eva Vargas Hazhir Teymourian Farshad Tehrani Ece Eksin Esther Snchez‐Tirado Paul Warren Arzum Erdem Eyal Dassau Joseph Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6442-6445
Performing bioassay formats based on enzyme and antibody recognition reactions with a single detection chip remains an unmet challenge owing to the different requirements of such bioassays. Herein, we describe a dual‐marker biosensor chip, integrating enzyme and antibody‐based assays for simultaneous electrochemical measurements of insulin (I) and glucose (G). Simultaneous G/I sensing has been realized by addressing key fabrication and operational challenges associated with the different assay requirements and surface chemistry. The I immunosensor relies on a peroxidase‐labeled sandwich immunoassay, while G is monitored through reaction with glucose oxidase. The dual diabetes biomarker chip offers selective and reproducible detection of picomolar I and millimolar G concentrations in a single microliter sample droplet within less than 30 min, including direct measurements in whole blood and saliva samples. The resulting integrated enzymatic‐immunoassay biosensor chip opens a new realm in point‐of‐care multiplexed biomarker detection. 相似文献
109.
Impedimetric Aptasensor Based on Disposable Graphite Electrodes Developed for Thrombin Detection 下载免费PDF全文
Ece Eksin Arzum Erdem Ayben Pınar Kuruc Hilal Kayi Aylin Öğünç 《Electroanalysis》2015,27(12):2864-2871
The impedimetric aptasensor for Thrombin (THR) was developed for the first time herein by measuring changes at the charge‐transfer resistance, Rct upon to protein? aptamer complex formation. After covalent activation of pencil graphite electrode (PGE) surface using covalent agents, amino linked aptamer (APT) was immobilized onto activated PGE surface. Then APT‐THR interaction was explored by electrochemical impedance spectroscopy (EIS). After the optimization of experimental conditions (e.g., APT and THR concentration, immobilization and interaction times), the selectivity of impedimetric aptasensor was tested in the presence of other biomolecules: factor Va and bovine serum albumine (BSA) both in buffer media, or in diluted fetal bovine serum (FBS). 相似文献
110.
DNA sensing strategies have recently been varieted with the number of attempts at the development of different biosensor devices based on nanomaterials, which will further become DNA microchip systems. The investigations at the side of material science in connection with electrochemical biosensors open new directions for detection of specific gene sequences, and nucleic acid-ligand interactions.An overview is reported here about nanomaterial-based electrochemical DNA sensing strategies principally performed for the analysis of specific DNA sequences and the quantification of nucleic acids. Important features of electrochemical DNA sensing strategies, along with new developments based on nanomaterials are described and discussed. 相似文献