Electrochemical Detection of a Cancer Biomarker mir‐21 in Cell Lysates Using Graphene Modified Sensors

In the present study, the voltammetric and impidimetric detection of microRNA‐21, mir‐21 from cell lysates was investigated for the first time by using graphene modified disposable pencil graphite electrodes (GME). The surface characterization of GME was performed via electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Upon passive adsorption of inosine substituted antimicroRNA‐21, antimir‐21 probe, InP, onto the surface of GME and then solid phase hybridization of InP with mir‐21, the target, the electrochemical detection was performed by using Differential Pulse Voltammetry (DPV) and EIS techniques. This developed biosensor, GME has presented a 2.77 times lower detection limit of 2.09 µg/mL (3.12 pmol) with respect to unmodified pencil graphite electrode (GE). Moreover it is capable of analyzing mir‐21 in the cell lysates of mir‐21 positive breast cancer cell line (MCF‐7) contrast to mir‐21 negative hepatoma cell line (HUH‐7). The proposed electrochemical yes‐no system does not require any purification and/or amplification step prior to fast detection of mir‐21 from real samples.     

Synthesis of N‐Alkylated Indolines and Indoles from Indoline and Aliphatic Ketones

A survey of redox aminations of indoline with aliphatic ketones using bismuth nitrate as catalyst is described. A reaction of an equivalent amount of indoline and aliphatic cyclic and acyclic ketones provides a mixture of excessive alkylated indole derivatives over typically redox isomerization and reductive alkylation pathways while using of the five equivalent of indoline provides N‐alkylated indolines as a reductive alkylation product. The desired N‐alkyl indoles from the oxidation of N‐alkyl indolines were obtained in excellent yields.     

Redox Amination Scope of Benzylic Ketones with Indoline: Synthetic and Mechanistic Insights

Bi(NO₃)₃·5H₂O‐Catalyzed redox amination scope and mechanistic insights of benzylic ketones with indoline are discussed. The experimental results demonstrate that the formation of N‐alkyl‐substituted indole/indoline derivatives over typically competitive redox and reductive amination processes is depending upon the reaction condition for the benzylic ketones.     

Photoluminescence and thermoluminescence properties of SnO2 nanoparticles embedded in Li20-K20-B203 with Cu-doping

Cu-doped borate glass co-doped with SnO2 nanoparticles is fabricated by melt quenching. The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy. Up-conversion enhancement is observed in the photoluminescence （PL） and thermolumines- cence （TL） intensities of the glass. PL emission spectra are identified in the blue and green regions, and a fourfold increase in emission intensity may be observed in the presence of embedded SnO2 nanoparticles. The glow curve is recorded at 215℃, and fourfold increases in TL intensity are obtained by addition of 0.1 mol% SnO2 nanoparticles to the glass. Higher TL responses of the samples are observed in the energy range of 15-100 KeV. At energy levels greater than -0.1 MeV, however, flat responses are obtained. The activation energy and frequency factor of the second-order kinetic reaction are calculated by the peak shape method.     

Surface modification and characterization of phenanthroline nanofilms on carbon substrate

Modification of glassy carbon (GC) surfaces with phenanthroline derivatives (PDs) such as 5‐amino‐1,10‐phenanthroline (5AP) and 5,6‐diamino‐1,10‐phenanthroline (56DAP) is described in this study. Surface modification experiments were performed by cyclic voltammetry (CV) scanning from + 1.2 to + 2.7 V at scan rate of 100 mV/s applying 30 potential scans in acetonitrile (CH₃CN) containing 1 mM PDs and 100 mM tetrabutylammoniumtetrafluoroborate (TBATFB). The presence of PDs on GC electrode was confirmed using CV, electrochemical impedance spectroscopy (EIS), contact angle measurements and ellipsometry and comparing with the results of bare GC electrode. A mechanism was proposed for the electrochemical modification of the GC electrode surface with PDs. The structure of the 5AP and 56DAP films was also discussed in the light of electrochemical and spectroscopic data. The complex‐forming ability of the modified surfaces against metal cations was investigated by square‐wave voltammetry (SWV). It was shown that surfaces having 1,10‐phenanthroline ligands with different functional groups were quite useful for the determination of transition metal ions. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of Polycondensation Reaction Conditions on the Properties of Thermotropic Liquid‐Crystalline Copolyester

In this study a range of wholly aromatic copolyesters based on kink m‐acetoxybenzoic acid (m‐ABA) monomer (33 mol%) and equimolar‐linear p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA) and terephthalic acid (TPA) monomers (67 mol%) have been synthesized by melt polycondensation reaction process at 280°C and 260°C for different time intervals. Characterization of copolyesters were performed by solution viscosity measurement, wide–angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), hot‐stage polarized light microscopy, proton‐nuclear magnetic resonance analysis (¹H‐NMR). According to the results obtained, copolyesters showed thermotropic liquid crystalline behavior in an appropriate temperature range. The copolyesters were prepared in high yields. It was observed that the intrinsic viscosities of the copolyesters are increased regularly with increasing polymerization time and temperature. All the copolyesters were soluble in a trifluoroacetic acid/dichloromethane (30:70 v/v) except the copolyesters which were synthesized at 280°C in 5 h. According to the WAXD results; the degree of crystallinity of copolyesters were found to be between 5–15%. DSC and hot stage polarized light microscopy results showed that all the copolyesters are melt processable and a significant molecular interaction exist in a very broad temperature range (160°C and 165°C) in the nematic mesophase. The T_g values are increased with an increasing polycondensation reaction time and temperature and they were observed between 93–126°C. Fibers prepared by a hand‐spinning technique from the polymer melt exhibit well‐developed fibrillar structure parallel to the fiber axis.     

An experimental investigation on interior thermal conditions and human body temperatures during cooling period in automobile

Determining the thermal conditions in an automobile and their effects on the driver is an important issue from both thermal comfort and driving safety points of view. Especially in hot summer season, the interior thermal conditions in automobile change rapidly when the air conditioning unit runs. In this study, standard air conditioning system is switched in an automobile parked in the sun and then the interior thermal conditions of the automobile are determined in detail during the 1-h cooling period. During the period, relative humidity, air velocity, air and surface temperature measurements are taken at numerous locations in the automobile. Moreover, in order to evaluate the effects of transient interior thermal conditions on the occupant, the skin temperatures of human body are measured at nine points. In addition to this, the thermal sensation of the human subject is also questioned during the cooling period. Subjective thermal comfort data is recorded using a questionnaire. The series of tests are conducted on two different automobiles, and the experimental results for both automobiles are presented and scrutinized.