bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyaniline, ethylene vinyl acetate semi‐conductive composites as pressure sensitive sensor
Authors: Rahaman M. , Chaki T. K. , Khastgir D. 
Published: June 2012

AbstractThis study focuses on the pressure sensitivity of ethylene vinyl acetate (EVA)/polyaniline (Pani) composites prepared through in situ polymerization of aniline in solutions of insulating EVA matrix. It is found that both DC and AC resistivity of the composites decreases with the increase in Pani concentration. The investigation shows that the composites senses to applied pressure through the decrease in resistivity with the increase in applied pressure. Moreover, the pressure sensitivity is also effective when the composites are kept under constant load for a period of time. Both DC and AC resistivity are found to decrease exponentially with respect to time. Relaxation time for the composites has been calculated and found that more time is required to be relaxed for the composite with lower Pani content. However, the composite with lower Pani content exhibits relatively higher change in electrical properties when subjected to both the applied pressure and time. The results show that these composites can be used as pressure sensitive sensor. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of gamma‐irradiation on the electret properties of poly(L‐lactide)
Authors: Yovcheva Temenuzhka , Marudova Mariya , Viraneva Asya , Gencheva Elena , Balabanov Nikola , Mekishev Georgi 
Published: June 2012

AbstractElectret stability of poly(L‐lactide) (PLA) films, gamma‐irradiated up to 100 kGy has been investigated by measuring the surface potential during the storage period. PLA samples—40‐μm thick films—were prepared by the casting method and then irradiated in a60Co radiation facility at a dose rate of 0.25 kGy/h. The structural changes during the irradiation were estimated by viscometric, differential scanning calorimetry and scanning electron microscope measurements. Random chain scission and appearance of end radicals are the most probable results of the irradiation process. After irradiation, the samples were charged in a corona discharge system and surface potential was measured by the method of the vibrating electrode with compensation. The values of the surface potential of the irradiated samples were higher in comparison with the non‐irradiated samples. This effect could be related to the degradation of the macromolecules and changes in the crystal state of PLA during the irradiation. Both of the mentioned factors lead to structural defects that increase the number of discrete trapping levels. The effect of low pressure on the surface potential drop was also investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Chiral separation with polyurea membrane consisting ofL‐lysinyl residue: Proposal of facile method for prediction of permselectivity
Authors: Hatanaka Makoto , Nishioka Yuki , Yoshikawa Masakazu 
Published: June 2012

AbstractNovel chiral polyureas were prepared fromL‐lysine‐4‐nitroanilide and 2,4‐toluene diisocyanate. The polyurea thus prepared gave a durable self‐standing membrane that can be directly converted into molecular recognition membranes by applying an alternative molecular imprinting. The Z‐D‐glutamic acid (D‐Glu) molecularly imprinted membrane adsorbedD‐Glu in preference toL‐glutamic acid (L‐Glu) from racemic mixture of Glu andvice versa. Those two types of molecularly imprinted membrane showed optical resolution ability, adopting a concentration gradient as a driving force for membrane transport. A facile method to predict permselectivity of racemic mixture of charged permeant was proposed. From the observed membrane resistance, the permselectivity was predicted. The predicted permselectivity coincided with the observed one. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structure and thermomechanical properties of stretched cellulose films
Authors: Kim Jae‐Woo , Park Sunkyu , Harper David P. , Rials Timothy G. 
Published: June 2012

AbstractRegenerated and stretched cellulose films were investigated for structure and thermomechanical properties as a potential packaging material. Cellulose films were cast from lithium chloride/N, N‐dimethylacetamide and were stretched up to 30% in a dynamic mechanical analyzer sample holder. Wide‐angle X‐ray diffraction analysis indicated that the orientation factor was significantly increased due to stretching. In addition, the stretched films have a higher resistance to the thermal decomposition from thermo gravimetric analysis. The increased orientation of cellulose crystalline structure by the stretching process also increased the storage modulus of cellulose films characterized by dynamic mechanical analysis, which suggest that mechanical properties of cellulose films could be tuned during the stretching process. The α2 and α1 relaxations were found at 240 and 300°C, respectively, which are attributed to the micro‐Brownian motion of segments in amorphous region, and activation energies for relaxations were determined with the stretching levels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polypyrrole/MnO2 composites and their enhanced electrochemical capacitance
Authors: Zhang Ai‐Qin , Xiao Yuan‐Hua , Lu Ling‐Zhen , Wang Li‐Zhen , Li Feng 
Published: June 2012

AbstractThe composites of polypyrrole (PPY) and MnO2 have been prepared through chemical oxidation of pyrrole monomer and MnO2 suspension with ammonium peroxysulfate at low temperature. The morphology and structure of materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Transmission electron microscopy (TEM), thermal gravity analysis ‐ differential thermal gravity (TG‐DTG), and X‐ray diffraction (XRD) measurements. The electrochemical properties of the composite were investigated by galvanostatic charge–discharge and electrochemical impedance spectroscopy. The specific capacitance of the composite electrode is 352.8 F/g at a current of 8 mA/cm2 in Na2SO4 electrolyte of 0.5 mol/L, which is much higher than that of 246.2 F/g and 103.5 F/g of PPY and MnO2, respectively. A convenient and effective technique has been developed to fabricate composite materials of PPY and MnO2 promising for designing new capacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Fabrication of a novel polyethylene/starch blend through mediation of a high‐energy ball milling process: Mechanical properties and formation mechanism
Authors: Sharif Alireza , Aalaie Jamal , Shariatpanahi Homeira , Hosseinkhanli Homayoon , Khoshniyat Alireza 
Published: June 2012

AbstractHigh‐energy ball milling (HEBM) was performed before melt mixing to fabricate a novel blend containing 85 wt % of a high density polyethylene (HDPE) and 15 wt % of a maize starch, using neither compatibilizer nor plasticizer materials in the blend formulation. Scanning electron microscopy and rheometry results revealed a strong interface between the two phases of the blend. Formation of the interface with high strength was ascribed to the grafting reactions, taking place between the phases during the HEBM process, and corroborated by Fourier transform infrared characterizations. A possible formation mechanism for the starch‐grafted polyethylene was proposed based on the measurements and comprehensive analysis. Interestingly enough, when compared to HDPE mixtures which contained the same amount of the starch, but were made only by conventional melt blending, the ball mill‐mediated sample showed superior mechanical and biodegradation properties. These properties enhancements were related to both the HDPE/starch strong interface and the damaged starch originated by the mechanical action of the milling process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Antimycobacterial Activity of Pyrimido[4,5‐b]diazepine Derivatives
Authors: Insuasty Braulio , García Angélica , Bueno Juan , Quiroga Jairo , Abonia Rodrigo , Ortiz Alejandro 
Published: June 2012

AbstractThree series of novel 8,9‐dihydro‐7H‐pyrimido[5,4‐b][1,4]diazepines, 4a–d, 5a–d, and 7a–d, were efficiently obtained in good yields using simple reaction methodologies. These pyrimidodiazepines were evaluated against 15 Mycobacterium spp. strains. Moderate activity in the inhibition of 13 microorganisms was obtained for the four compounds 4a, 5a, 5c, and 5d.
Synthesis and Evaluation of Benzophenone O‐Glycosides as α‐Glucosidase Inhibitors
Authors: Liu Qingchao , Guo Tiantian , Li Wenhong , Li Dong , Feng Zili 
Published: June 2012

AbstractThe first total synthesis of benzophenone O‐glycosides (iriflophenone 2‐O‐α‐L‐rhamnopyranoside: 1 and aquilarisinin: 2) isolated from the leaves of Aquilaria sinensis and related new derivatives (3–12) was accomplished through suitable protecting group manipulations and glycosylation starting from commercially available L‐rhamnose, D‐glucose, D‐galactose, D‐mannose, D‐xylose, and 1,3,5‐trihydroxybenzene. All synthesized benzophenone O‐glycosides were evaluated for their inhibitory activities against α‐glucosidase. Of these, benzophenone O‐glycosides 4 and 10 exhibited the most potent inhibitory activity in vitro against α‐glucosidase with IC50 values of 168.7 ± 13.9 and 210.1 ± 23.9 µM, respectively, when compared with that of the positive control acarbose with an IC50 value of 569.3 ± 49.7 µM.
Synthesis of Mesoporous Platinum–Palladium Alloy Films by Electrochemical Plating in Aqueous Surfactant Solutions
Authors: Wang Hongjing , Yamauchi Yusuke 
Published: June 2012

AbstractMesoporous platinum–palladium alloy films with different compositional ratios have been successfully synthesized by electrochemical plating in aqueous surfactant solutions. Scanning electron micrographs and transmission electron micrographs reveal that all of the platinum–palladium alloy films possess uniform mesopores with a narrow size distribution (around 7 nm). The alloy compositions in the pore walls can be controlled by changing the compositional ratios in the precursor solutions, as confirmed by inductively coupled plasma mass spectroscopy analysis and X‐ray photoelectron spectroscopy measurements. Due to large surface areas, the prepared mesoporous platinum–palladium films show distinctly enhanced electrocatalytic activity for methanol oxidation reactions, compared with the commercially available platinum black catalyst. Furthermore, compared with mesoporous platinum film, the alloying of platinum with palladium has a critical effect on the enhanced electrocatalytic activity. In particular, a mesoporous Pt82–Pd18 film exhibits highly enhanced electrocatalytic activity.
A Urea Precursor to Synthesize Carbon Nitride with Mesoporosity for Enhanced Activity in the Photocatalytic Removal of Phenol
Authors: Lee Shu Chin , Lintang Hendrik O. , Yuliati Leny 
Published: June 2012

AbstractA urea precursor was used for the first time to prepare mesoporous carbon nitride (MCN) by a thermal polymerization process with silica nanospheres as a hard template. Although the prepared MCN samples have similar structures and optical properties, it was revealed that the specific surface area, pore‐size distribution, and morphology of the MCN samples depend on the initial mass ratio of urea to silica. Compared to the bulk carbon nitride (BCN) that only gave 20 % phenol removal (6 h of irradiation), the activities can be enhanced up to 74 % on MCN samples for photocatalytic removal of phenol under visible‐light irradiation. The highest conversion was obtained on MCN with an initial mass ratio of urea to silica of 5, which has high surface area of 191 m2 g−1 and a nanoporous structure with uniform pore‐size distribution of 7 nm. In addition to the high activity, the MCN sample also showed high photocatalytic stability.
Photoluminescence of Alq3‐ and Tb‐activated aluminium–tris(8‐hydroxyquinoline) complex for blue chip‐excited OLEDs
Authors: Yawalkar P. W. , Dhoble S. J. , Thejo Kalyani N. , Atram R. G. , Kokode N. S. 
Published: June 2012

ABSTRACTThe tris(8‐hydroxyquinoline)–aluminium complex is the most important and widely studied as electron transporting and green light emitting material. Alq3 and TbxAl(1‐x)q3 have been synthesized (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) and blended films of Alq3 and TbxAl(1‐x)q3 with PMMA and PS at different percentage weight (wt%) concentrations (e.g., 0.1, 1, 5, 10, 25 and 50 wt%) have been prepared. The synthesized materials and their blended thin films have been characterized by a photoluminescence (PL) technique; the synthesis and PL characterization are reported in this paper. The synthesized metal complex shows bright emission of green light with blue light excitation (440 nm) and the prepared TbxAl(1‐x)q3 phosphor may be applicable in blue chip‐excited OLEDs for the newly developed wallpaper lighting technology. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis, effect of capping agents and optical properties of manganese‐doped zinc sulphide nanoparticles
Authors: Murugadoss G. , Ramasamy V. 
Published: June 2012

ABSTRACTMn2+‐doped ZnS nanoparticles have been successfully synthesized by a chemical precipitation method, using non‐ionic surfactants such as PMMA and PEG. The particles were prepared in an air atmosphere at 80°C. X‐ray diffraction (XRD), transmission electron microscopy (TEM), UV‐visible and photoluminescence (PL) studies were used to investigate the effect of the capping agent on the size, morphology and optical properties of the ZnS–Mn2+ nanoparticles. Enhanced PL was observed from the surfactant‐capped ZnS–Mn2+ nanoparticles. The PL spectra showed a broad blue emission band in the range 460–445 nm and a Mn2+‐related yellow‐orange emission band in the range 581–583 nm. Copyright © 2012 John Wiley & Sons, Ltd.
Amino acids as chiral selectors in enantioresolution by liquid chromatography
Authors: Bhushan Ravi , Dixit Shuchi 
Published: June 2012

ABSTRACTAmino acids are unique in terms of their structural features and multidimensional uses. With their simple structures and the ready availability of both enantiomers, amino acids not only serve as a chiral pool for synthesis but also provide an inexpensive pool for resolution studies. There has been no attempt to review the application of amino acids as chiral selectors for chromatographic enantioresolution of pharmaceuticals and other compounds. The present paper deals with application of l‐amino acids and complexes of l‐amino acids with a metal ion, particularly Cu(II), as an impregnating reagent in thin‐layer chromatography or as a chiral ligand exchange reagent or a chiral mobile phase additive in both thin‐layer chromatography and high‐performance liquid chromatography. Enantiomeric resolution of β‐blockers, nonsteroidal anti‐inflammatories, amino acids (and their derivatives) and certain other compounds is discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of toosendanin in rat plasma by ultra‐performance liquid chromatography–electrospray ionization–mass spectrometry and its application in a pharmacokinetic study
Authors: Wang Xintang , Wang Changhong , Wang Zhengtao 
Published: June 2012

ABSTRACTToosendanin (TSN) is a major triterpenoid existing in Melia toosendan, which has been used as a digestive tract parasiticide and insecticide but with serious hepatotoxicity. An ultra‐performance liquid chromatography–electrospray ionization–mass spectrometry method was developed for determination of TSN in rat plasma. Plasma samples were separated on Acquity UPLCTM BEH C18 column with acetonitrile and water as flow phase by gradient elution and determined by quadrupole mass spectrometer in negative selective ion monitoring mode. Usolic acid was used as internal standard. The calibration curves were linear over 0.02–3.0 µg/mL for TSN with a lower limit of quantification (LLOQ) of 20 ng/mL in rat plasma. The extraction recoveries of TSN were within 74.3–80.7% with an accuracy of 94.5–108.9%. The intra‐ and inter‐day precision values of the assay at three quality control levels were 8.8–13.8% and <13.9% at LLOQ level, respectively. The method was successfully applied to a pharmacokinetic study of TSN in rats after a single intravenous and oral administration of 2 and 60 mg/kg. The shorter Tmax, higher Vd and Cl of TSN after oral administration indicated that TSN could be absorbed, distributed and eliminated quickly in rats in vivo. The absolute bioavailability of TSN after oral administration was 9.9%. Copyright © 2012 John Wiley & Sons, Ltd.
A Multicoincidence Study of Fragmentation Dynamics in Collision of γ‐Aminobutyric Acid with Low‐Energy Ions
Authors: Capron Michael , Díaz‐Tendero Sergio , Maclot Sylvain , Domaracka Alicja , Lattouf Elie , Ławicki Arkadiusz , Maisonny Rémi , Chesnel Jean‐Yves , Méry Alain , Poully Jean‐Christophe , Rangama Jimmy , Adoui Lamri , Martín Fernando , Alcamí Manuel , Rousseau Patrick , Huber Bernd A. 
Published: June 2012

AbstractFragmentation of the γ‐aminobutyric acid molecule (GABA, NH2(CH2)3COOH) following collisions with slow O6+ions (v≈0.3 a.u.) was studied in the gas phase by a combined experimental and theoretical approach. In the experiments, a multicoincidence detection method was used to deduce the charge state of the GABA molecule before fragmentation. This is essential to unambiguously unravel the different fragmentation pathways. It was found that the molecular cations resulting from the collisions hardly survive the interaction and that the main dissociation channels correspond to formation of NH2CH2+, HCNH+, CH2CH2+, and COOH+fragments. State‐of‐the‐art quantum chemistry calculations allow different fragmentation mechanisms to be proposed from analysis of the relevant minima and transition states on the computed potential‐energy surface. For example, the weak contribution at [M−18]+, whereMis the mass of the parent ion, can be interpreted as resulting from H2O loss that follows molecular folding of the long carbon chain of the amino acid.
Pd/Light‐Accelerated Atom‐Transfer Carbonylation of Alkyl Iodides: Applications in Multicomponent Coupling Processes Leading to Functionalized Carboxylic Acid Derivatives
Authors: Fusano Akira , Sumino Shuhei , Nishitani Satoshi , Inouye Takaya , Morimoto Keisuke , Fukuyama Takahide , Ryu Ilhyong 
Published: June 2012

AbstractThe atom‐transfer carbonylation reaction of various alkyl iodides thereby leading to carboxylic acid esters was effectively accelerated by the addition of transition‐metal catalysts under photoirradiation conditions. By using a combined Pd/hν reaction system, vicinal C‐functionalization of alkenes was attained in which α‐substituted iodoalkanes, alkenes, carbon monoxide, and alcohols were coupled to give functionalized esters. When alkenyl alcohols were used as acceptor alkenes, three‐component coupling reactions, which were accompanied by intramolecular esterification, proceeded to give lactones. Pd‐dimer complex [Pd2(CNMe)6][PF6]2, which is known to undergo homolysis under photoirradiation conditions, worked quite well as a catalyst in these three‐ or four‐component coupling reactions. In this metal/radical hybrid system, both Pd radicals and acyl radicals are key players and a stereochemical study confirmed the carbonylation step proceeded through a radical carbonylation mechanism.
Ionic‐Liquid‐Derived, Water‐Soluble Ionic Cellulose
Authors: Vo Huyen Thanh , Kim Young Jin , Jeon Eun Hee , Kim Chang Soo , Kim Hoon Sik , Lee Hyunjoo 
Published: June 2012

AbstractA new type of water‐soluble ionic cellulose was obtained by means of the dissolution of cellulose in dimethylimidazolium methylphosphite at elevated temperatures over 120 °C. FTIR spectroscopy, 1H and 13C NMR spectroscopy, and elemental analysis results revealed that the repeating unit of the water‐soluble cellulose consists of a dialkylimidazolium cation and a phosphite anion bonded to cellulose. The degree of phosphorylation on the cellulose chain was between 0.4 and 1.3 depending on the reaction temperature and time. With an increasing degree of phosphorylation, water solubility was increased. Scanning electron microscopy and X‐ray diffraction analyses revealed that the cellulose crystalline phase in the parent crystalline cellulose changed to an amorphous phase upon transformation into ionic cellulose. Thermogravimetric analysis showed the prepared phosphorylated cellulose was stable over 250 °C and a substantial amount of residue remained at 500 °C.
Large‐Scale Synthesis of High‐Quality Metal Sulfide Semiconductor Quantum Dots with Tunable Surface‐Plasmon Resonance Frequencies
Authors: Kanehara Masayuki , Arakawa Hisamitsu , Honda Tetsuya , Saruyama Masaki , Teranishi Toshiharu 
Published: June 2012

AbstractHigh‐quality CdS and Cu7S4 quantum dots (QDs) were synthesized with N,N‐dibutylthiourea (DBTU) as an organic sulfur source. In this method, nucleation and growth reactions were controlled simply by the heating rate of the reaction. The mild oxidation conditions gave monodisperse CdS QDs exhibiting pure band‐edge emission with relatively high photoluminescence quantum yield. During the synthesis of Cu7S4 QDs, the addition of dodecanethiol to the reaction system controlled the reaction rate to give monodisperse spherical or disk‐shaped QDs. A hundred‐gram scale of copper precursor could be used to generate the high‐quality Cu7S4 QDs, indicating that an industrial‐scale reaction is achievable with our method. As observed in anisotropic noble‐metal nanocrystals, larger disk‐shaped Cu7S4 QDs showed lower localized‐surface‐plasmon resonance energy in the near‐infrared region. The disk‐shaped Cu7S4 QDs could be used effectively as templates to form cation‐exchanged monodisperse disk‐shaped CdS QDs.
Enantioselective Toxic Effects of Hexaconazole Enantiomers Against Scenedesmus Obliquus
Authors: Huang Ledan , Lu Dahai , Zhang Ping , Diao Jinling , Zhou Zhiqiang 
Published: June 2012

ABSTRACTEnantioselectivity in ecotoxicity of chiral pesticides in the aquatic environment has been a subject of growing interest. In this study, the toxicological impacts of hexaconazole enantiomers were investigated with freshwater algae Scenedesmus obliquus. After 96 h of exposure, the EC50 values for rac‐hexaconazole, (+)‐hexaconazole, and (−)‐hexaconazole were 0.178, 0.355, and 0.065 mg l−1, respectively. Therefore, the acute toxicities of hexaconazole enantiomers were enantioselective. In addition, the different toxic effects were evaluated when S. obliquus were exposed to 0.2, 0.5, and 1.0 mg l−1 of rac‐hexaconazole, (+)‐hexaconazole, and (−)‐hexaconazole during 96 h, respectively. The chlorophyll a and chlorophyll b contents of S. obliquus treated by (−)‐hexaconazole were lower than those exposed to (+)‐hexaconazole, whereas the malondialdehyde contents of S. obliquus treated by (−)‐form were higher than those exposed to (+)‐form at higher concentrations. In general, catalase activities were significantly upregulated by exposure to (−)‐enantiomer than (+)‐enantiomer at all three concentrations. However, superoxide dismutase activities exposed to (−)‐hexaconazole were lower than that exposed to (+)‐hexaconazole at 0.2 mg l−1 and 0.5 mg l−1. On the basis of these data, the acute toxicity and toxic effects of hexaconazole against S. obliquus were enantioselective, and such enantiomeric differences must be taken into consideration in pesticide risk assessment. Chirality 24:610–614, 2012. © 2012 Wiley Periodicals, Inc.