bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Structure Analysis of Aurivillius Phases Pb1‐xBi4‐+Ti1‐xMnxO15
Authors: Zulhadjri  , Prijamboedi B. , Nugroho A. A. , Ismunandar  
Published: May 2015

AbstractSynthesis Pb1‐xBi4+xTi4‐xMnxO15 compounds (0 ≤ × ≤ 1) were carried out by molten salts method using eutectic mixture of Na2SO4/K2SO4 salts (1:1 molar ratio) as the flux. The samples were characterized by X‐ray powder diffraction and refined by Le Bail method using Rietica program. The refinement results revealed that the compounds with the composition 0 ≤ x ≤ 0.6 formed Aurivillius phase with the space group A21am while the other composition (x ≥ 0.8) showed another phase beside A21am. The ratio b/a of the lattices constants for all the samples are larger than 1 indicating the direction of the orthorhombic along the b axis of their cells. The lattice parameters and volume of the unit cells decrease as the Mn content increasing from x = 0 to 0.6, for x ≥ 0.8 a second phase were observed. The morphologies of Pb1‐xBi4+xTi4‐xMnxO15 samples were observed by SEM and show plate‐like aggregate crystals, typical of layered compounds belonging to the Aurivillius phase.
Preparation of Antibacterial Waterborne Polyurethane/silver Nanocomposite
Authors: Wu Chein‐I , Huang Jiann‐Wen , Wen Ya‐Lan , Wen Shaw‐Bing , Shen Yun‐Hwei , Yeh Mou‐Yung 
Published: May 2015

AbstractStable aqueous dispersions of silver (Ag) nanoparticles were prepared by reducing silver nitrate solutions with sodium borohydride (NaBH4) in the presence of waterborne polyurethane as a stabilizing agent. WPU/Ag nanocomposites were obtained after evaporating water. Transmission electron microscope (TEM) shows nanoscale Ag particles are well dispersed in WPU matrix at a lower concentration, while particles exhibit a little aggregation at a higher concentration. UV‐visible spectra, X‐ray powder diffraction, and energy dispersive X‐ray spectrometer (EDS) confirm the existence of Ag particle in WPU matrix. The WPU/Ag composite films show good antibiotic ability.
Shape‐Selective Alkylation of Naphthalene over Zeolites: Steric Interaction of Reagents with Zeolites
Authors: Sugi Yoshihiro 
Published: May 2015

AbstractSteric interaction of reagents with zeolites was studied in isopropylation, sec‐butylation, and tert‐butylation of naphthalene (NP) over several large‐pore zeolites to elucidate the mechanism of selective catalysis. Selectivities for dialkylnaphthalene (DAN) isomers were influenced by the type of zeolite and bulkiness of alkylating agent. Selective formation of β,β‐ and 2,6‐diisopropylnaphthalene (DIPN) occurred only over H‐mordenite (MOR) in the isopropylation of NP using propene; bulky transition states of α,α‐ and α,β‐DIPN are excluded because of steric restriction by the channels, resulting in selective formation of β,β‐ and 2,6‐DIPN. However, low selectivities for β,β‐ and 2,6‐DIPN were observed over the zeolites, SSZ‐24 (AFI), SSZ‐55 (ATS), and SSZ‐42 (IFR) with 12‐membered‐ring (12‐MR) pore entrances of one‐dimensional channels, CIT‐5 (CFI), UTD‐1 (DON), and SSZ‐53 (SFH) with 14‐membered‐ring (14‐MR) pore entrances of one‐dimensional channels, and Y‐zeolite (FAU), zeolite β (BEA), and CIT‐1 (CON) with 12‐MR pore entrances of three‐dimensional channels, because their channels are too large for the exclusion of bulky isomers. Catalysis over these zeolites occurs under kinetic and/or thermodynamic control, resulting in predominant formation of α,α‐ and α,β‐DIPN at lower temperatures and an increase of the stable isomer β,β‐DIPN at higher temperatures.The selectivities for β,β‐ and 2,6‐DAN were enhanced with the increase in bulkiness of alkylating agents: 1‐butene for sec‐butylation and 2‐methylpropene for tert‐butylation. In particular, β,β‐di‐tert‐butylnaphthalene (DTBN) was selectively formed in the tert‐butylation. The selectivities for β,β‐ and 2,6‐DAN were enhanced even in large channels: the transition states of the least bulky isomers only fit the channels because other bulky isomers are excluded by steric restriction of the channels. However, tert‐butylation over FAU, BEA, and CON had selectivities for 2,6‐DTBN of around 50–60%, although selectivities for β,β‐DTBN were almost 100% selectivity; these zeolites can hardly recognize the differences between 2,6‐ and 2,7‐DTBN. The results indicate that the fitting of the least bulky isomers to zeolite channels, leading to the exclusion of other bulky isomers, is essential for highly shape‐selective catalysis.
A Simple and Cheap Device for Colorimetric Determination of Serum Iron
Authors: Sorouraddin M. H. , Saadati M. , Samadi A. 
Published: May 2015

AbstractA simple and cheap device for colorimetric determination of serum iron and TIBC (total iron‐binding capacity) was devised. The proposed device employs an LED as a light source and a common light dependent resistor (LDR) as a detector. This device functions on the basis of the light intensity received by LDR, connected to a digit multimeter, yielding resistance readings. The serum, standard, and blank solutions were prepared according to the kits instructions and introduced into the colorimeter with a disposable syringe. The iron content of the serum was calculated from the resistance difference of serum and standard solutions. The precision of the method was assessed with two commercially available serum‐based chemistry controls. The values obtained with the proposed device indicated that the serum iron concentrations correlated well with the values obtained with the commercial automated analyzer. The calibration graph was linear for iron concentrations up to 90 μmol/L (500 μg/dL). The proposed fabricated colorimeter is considerable cheaper, requires smaller sample volumes, and is suitable for serum iron assay.
A LC Separation and Quantification of o‐Toluene Sulphonamide and its Related Positional Isomers Using a Cellulose tris(3,5‐dimethyl phenylcarbamate)
Authors: Krishnaiah Charagondla , Reddy Anumula Raghupathi , Kumar Ramesh , Mukkanti Khagga 
Published: May 2015

AbstractA simple, rapid, selective and sensitive high performance liquid chromatographic method was developed for the separation and quantification of o‐Toluene Sulphonamide and its positional isomers which is an intermediate of Zafirlukast drug substance using a chiral column. Elution time was below 10 min in normal phase mode and ultra violet detection was carried out at 220 nm. Efficient separation was achieved on a Chiralcel OD‐H column using of n‐Hexane and 2‐Propanol mixture (50:50 v/v) as isocratic at 1.0 mL min−1 flow rate. Resolutions between m‐Toluene Sulphonamide and p‐Toluene Sulphonamide isomers of o‐Toluene Sulphonamide were found to be >; 2.5. The calibration graphs for m‐Toluene Sulphonamide and p‐Toluene Sulphonamide isomers of o‐Toluene Sulphonamide were linear (R2 > 0.999) when ranging from the limit of quantitation to 0.5%. The method is found to be selective, precise, linear, accurate and also robust. It was used for not only Quality assurance but also monitoring the synthetic reactions involved in the process development of Zafirlukast. The liquid chromatographic method is found to be specific and reliable for the determination of unreacted levels of positional isomers in reaction mass. This method was successfully validated according to the International Conference Harmonization (ICH) guidelines (Validation of Analytical Procedures: Test and Methodology Q2).
Synthesis, Characterization and Crystal Structure of Some Novel 1‐Aryl‐2‐Thioxo‐2,3‐Dihydro‐1H‐Quinazolin‐4‐Ones
Authors: Saeed Aamer , Shaheen Uzma , Bolte Michael 
Published: May 2015

AbstractThe base catalyzed intramolecular nucleophilic cyclization of 1‐(2‐haloaroyl)‐3‐aryl thioureas (1a‐i), in the presence of DMF afforded the 1‐aryl‐2‐thioxo‐2,3‐dihydro‐1H‐quinazolin‐4‐ones (2a‐i). The structures were confirmed by spectroscopic data, elemental analyses and in case of the 2c by single crystal X‐ray diffraction data. The mechanistic studies support an intramolecular nucleophilic substitution (SNAr mechanism) rather than intramolecular aromatic substitution (SRN1 mechanism).
Dispersive Liquid‐Liquid Microextraction of Cu(II) Using a Novel Dioxime for Its Highly Sensitive Determination by Graphite Furnace Atomic Absorption Spectrometry
Authors: Hashemi Payman , Hosseini Sayyed Mohammad , Kakanejadifard Ali , Azimi Gholamhassan , Zohrehvand Somayeh 
Published: May 2015

AbstractA dispersive liquid‐liquid microextraction (DLLME) technique was proposed for the enrichment and graphite furnace atomic absorption spectrometric (GFAAS) determination of Cu2+ in water samples.In this method a mixture of 480 μL acetone (disperser solvent) containing 26 μg S,S‐bis(2‐aminobenzyl)‐dithioglyoxime (BAT) ligand and 20 μL carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5 mL aqueous sample containing copper ions (analyte). Thereby, a cloudy solution formed. After centrifugation, the fine droplets containing the extracted copper complex were sedimented at the bottom of the conical test tube. This phase was collected by a microsyring and after dilution by methanol, 20 μL of it was injected into the graphite tube of the instrument for analysis.Effects of some parameters on the extraction, such as extraction and disperser solvent type and volume, extraction time, salt concentration, pH and concentration of the chelating agent were optimized. The response surface method was used for optimization of the effective parameters on the extraction recovery. Under these conditions, an enrichment factor of 312 was obtained. The calibration graph was linear in the rage of 2–50 μ L−1 Cu2+ with a detection limit of 0.03 μg L−1 and a relative standard deviation (RSD) for five replicate measurements of 3.4% at 20 μg L−1 Cu2+. The method was successfully applied to the determination of Cu2+ in some spring water samples.
Construction of Physical Models for Arbitrary Fullerenes with Beads: Realization of Tangent‐Sphere Model
Authors: Jin Bih‐Yaw , Chuang Chern , Tsoo Chia‐Chin 
Published: May 2015

AbstractIn this article, we show a simple way to realize the tangent‐sphere model for constructing physical models of arbitrary fullerenes based on beads commonly used in the ornaments and decorative arts. Using suitably chosen weaving strategy, the beaded model can be made to be a faithful π‐bond representation of the corresponding fullerene. Moreover, the shape of a particular beaded model is usually quite close to the true molecular structure of the corresponding fullerene because there is an interesting analogue between microscopic valence shell electron pair repulsion and macroscopic mechanical hard‐sphere interaction in the trivalent beaded models. Systematic rules for constructing fullerenes without any hole are discussed.
Syntheses of (±)‐Curcuphenol, (±)‐Curcudiol and (±)‐Curcuhydroquinone: A Johnson‐Claisen Rearrangement Approach
Authors: Du Zhen‐Ting , Yu Hong‐Rui , Xu Yan , Song Qi‐Liang , Li An‐Pai 
Published: May 2015

AbstractThe synthesis of (±)‐curcuphenol 1, (±)‐curcudiol 2, (±)‐curcuhydroquinone 3 and (±)‐curcuquinone 4 had been achieved, in which the Johnson‐Claisen rearrangement was used as key step.
Electrochemical Deposited Nanoflakes Co(OH)2 Porous Films for Electrochemical Capacitors
Authors: Yu Zhan‐Jun , Dai Ying , Chen Wen 
Published: May 2015

AbstractNanoflakes Co(OH)2 porous films have been successfully electrochemical deposited on nickel foam substrate from cobalt nitrate dissolved in water and water‐ethanol (1:1 volume ratio) solutions, respectively. Field emission scanning electron microscope (FESEM) studies indicate that the films electrodeposited from both solutions have nanoflakes porous structure. Cyclic voltammetry (CV) and galvanostaitc charge/discharge measurements show that the Co(OH)2 films electrode deposited in water‐ethanol solution has excellent electrochemical capacitance between a potential range of 0‐0.4 V, and the maximum specific capacitance as high as 2369 F g−1 could be achieved in 2 M KOH solution at a charge‐discharge current density of 2 A g−1, suggesting its potential application in the electrode material for electrochemical capacitors. Meanwhile, the properties of the nanoflakes Co(OH)2 porous films electrodeposited in water solution are also discussed for comparison.
Development of a Controlled Environment Near‐Field Optical Microscope for Organic Thin Film Studies
Authors: Li Tai‐De , Inigo Anto Regis , Fann Wunshain , White Jonathon D. , Huang Yi‐Fang , Wei Pei‐Kuen 
Published: May 2015

AbstractThe requirements of a microscope differ greatly from field to field and with the sample being studied. Organic thin films are highly sensitive to environmental conditions being rapidly photobleached in the presence of oxygen. In this paper we introduce the design of a low cost near field optical microscope suitable for environmentally controlled studies. We demonstrate that reducing ambient pressure to ∼10 mTorr (1.3 Pa) of nitrogen (a pressure accessible with a mechanical pump) significantly reduces photo‐bleaching on a typical experimental timescale. In addition, we introduce a novel non‐optical feedback control mechanism combining a piezoelectric diaphragm with a tuning fork. The morphology of thin films of MEH‐PPV spin cast from the polymer dissolved in chlorobenzene is investigated. These films are shown to be featureless on a 100 nm length scale in terms of topology, PL intensity and PL spectrum both before and during photo‐bleaching. As far as we are aware these are the first reported thin films of MEH‐PPV grown in which ∼100 nm sized domains are absent. We believe that the ability to control environment will not only allow better optical characterization of thin films but also opens up the possibility of the production of novel two dimensional organic photonic crystals through a combination of mechanical disruption, photo‐bleaching and photo‐conjugation of polymers.
Recombination Dynamics of the Enhanced Quantum Efficiency in CdSe/ZnTe/ZnS Type‐II Quantum Dots
Authors: Wang Chun‐Hsiung , Wei Chili‐Ming , Huang Sheng‐Chih , Chen Yang‐Fang , Lai Chih‐Wei , Ho Mei‐Lin , Chou Pi‐Tai 
Published: May 2015

AbstractRemarkable enhancement of the photoluminescence emission arising from CdSe/ZnTe/ZnS core‐shell type‐II quantum dots (QDs) has been observed when compared with their CdSe/ZnTe counterparts. Comprehensive studies on the recombination dynamics draw a conclusion that the underlying mechanisms such as reduction of the exciton‐phonon coupling strength and surface trapping play key roles for the improvement of optical properties. Our finding is important for the creation of highly efficient optoelectronic devices derived from type‐II semiconductor QDs.
Effects of β Phase on Light Emission from Polythiophenes‐Doped Polyfluorene
Authors: Chang Yung‐Cheng , Hsiao Chung‐Chin , Jen Tzu‐Hao , Liao Jin‐Long , Su An‐Chung , Chen Show‐An 
Published: May 2015

AbstractWhite light emission behavior of blue‐emitting poly(9,9‐di‐n‐octyl‐2,7‐fluorene) (PFO) blended with a minor amount (0.5 w%) of red‐emitting regio‐regular poly(3‐n‐hexyl‐2,5‐thiophene) (P3HT) was examined via photoluminescence (PL) and electroluminescence (EL). Use of different solvents (chloroform, tetrahydrofuran, and chlorobenzene, in decreasing order of vapor pressure) resulted in different levels of β phase development, as supported by optical absorption, PL/EL spectra, and atomic force microscopic observations. By means of time‐resolved EL, we show that both the β phase and the P3HT chains molecularly dispersed in the PFO matrix serve as carrier trapping/recombination sites, resulting in white light emission under various biases.
Application of Multi‐walled Carbon Nanotube Modified Carbon Ionic Liquid Electrode for the Voltammetric Detection of Dopamine
Authors: Qu Li‐Ning , Wu Jie , Sun Xiao‐Ying , Xi Meng‐Ying , Sun Wei 
Published: May 2015

AbstractIn this paper a carbon ionic liquid electrode (CILE) was fabricated by using ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) as the binder. Then a Nafion and multi‐walled carbon nanotubes (MWCNTs) composite material was further cast on the CILE surface to get a modified electrode denoted as Nafion‐MWCNTs/CILE. The fabricated electrode showed strong electrocatalytic ability to the oxidation of dopamine (DA) with a pair of well‐defined redox peaks appeared. Compared with other electrodes the redox peak currents increased with the decrease of the peak‐to‐peak separation (Δ Ep), and the result was attributed to the specific properties of MWCNTs and its interaction with imidazolium ion present on the CILE surface. The electrochemical parameters of DA on the Nafion‐MWCNTs/CILE were calculated with the electron transfer coefficient (α) as 0.433, the electron transfer number (n) as 1.1, the apparent heterogeneous electron transfer rate constant (ks) as 0.774 s−1 and the diffusion coefficient (D) as 3.05 × 10−5 cm2/s. Under the selected conditions the oxidation peak current was in linear with DA concentration from 1.0 × 10−5 to 6.0 × 10−4 mol/L with the detection limit as 6.75 × 10−6 mol/L (3σ)by differential pulse voltammetry. The proposed method showed good selectivity and was further applied to the DA injection samples determination with satisfactory results.
The Synthesis and Trapping of 1‐Naphthylcyclopropenes
Authors: Lee Gon‐Ann , Tsai Ru‐Ting , Wang Wen‐Chieh , Liu Yu‐Ting 
Published: May 2015

Abstract1‐Bromo‐2‐naphthylcyclopropene (8), an intermediate for the preparation of 1‐substituted 2‐naphth‐ylcyclopropenes, was synthesized by debromination of 1,1,2‐tribromo‐2‐naphthylcyclopropane (7). Compound 8 underwent bromo‐lithium exchange followed by nuclephilic substitution reactions to generate 1‐trimethylsilyl‐2‐naphthylcyclopropene (11) and 1‐naphthylcyclopropene (12). The cyclopropenes 8, 11, and 12 reacted with cyclopentadiene to form adducts 9, 13, and 14, respectively. All of these Diels‐Alder adducts are endo isomers.
Purification and Characterization of a Chitosanase and a Protease by Conversion of Shrimp Shell Wastes Fermented by Serratia Marcescens Subsp. Sakuensis TKU019
Authors: Liang Tzu‐Wen , Kuo Yi‐Hsuan , Wu Pei‐Chen , Wang Chuan‐Lu , Dzung Nguyen Anh , Wang San‐Lang 
Published: May 2015

AbstractA chitosanase and a protease were purified from the culture supernatant of Serratia marcescens subsp. sakuensis TKU019 with shrimp shell as the sole carbon/nitrogen source. The culture condition suitable for production of chitosanase was found to be shaken at 37 °C for 3 days in 100 mL of medium containing 0.5 % shrimp shell powder, 0.1 % K2HPO4 and 0.05 % MgSO4•7 H2O at pH 7. The TKU019 chitosanase was suppressed by the simultaneously existing protease, which also showed the maximum activity at the third day of incubation. The molecular masses of the chitosanase and protease determined by SDS‐PAGE were approximately 36 kDa and 58 kDa, respectively. Cu2+, Mn2+ and Zn2+ inhibited the chitosanase activity, and all of tested divalent metals inhibited in the protease activity. The optimum pH, optimum temperature, pH stability, and thermal stability of the chitosanase was pH 7, 60 °C, pH 4–7, and < 60 °C, respectively. The optimum pH, optimum temperature, pH stability, and thermal stability of the protease was pH 10, 50 °C, pH 5–10, and <50 °C, respectively. Tween 40 (2 %, v/v) had stimulatory effect on TKU019 protease activity.
Syntheses, Crystal Structure, and Magnetic Properties of a Self‐Assembling Dinickel(II) Helicate with Novel Bipyridine Ligand
Authors: Wang Wen‐Jwu , Wang Yi‐Chun , Kao Hsien‐Chang 
Published: May 2015

AbstractA novel polydentate ligand, L = 2,2′‐bipyridyl‐6,6′‐bis(2‐acetylpyrazinohydrazone), was synthesized by condensation of 6,6′‐dihydrazine‐2,2′‐bipyridine and 2‐acetylpyrazine. Reaction of L ligand strands with nickel (II) perchlorate in CH3CN generates a double helical dinuclear complex. Its complexation behavior was studied by UV‐Vis spectrophotometric titration experiments that revealed the formation of dinuclear complexes [Ni2L2](ClO4)4. Moreover, the double‐helical structure of [Ni2L2](ClO4)4 was confirmed by X‐ray diffractometer. Each nickel(II) center occupies a distorted octahedral environment. Variable‐temperature magnetic measurements revealed weak antiferromagnetic interactions between Ni(II) ion centers with J = −0.34 cm−1.
Oxidation of Catechols and Flavonoids by DPPH·
Authors: Lin Lu‐Ming , Li Wei‐Shuen , Chen Wei‐Lin , Yeh Andrew 
Published: May 2015

AbstractThe reaction of a series of catechols and dpph· has been studied in the methanol solution. The reaction underwent a two electron oxidation with the formation of quinone products. Detailed kinetic study shows that the rate law of the reaction involves the rate determining step of one‐electron oxidation of the catechols to form the corresponding semiquinone radicals, followed by the rapid scavenge of the radicals to form the final products. The specific rate constants, measured at μ = 0.10 M [(n‐Bu)4N]ClO4, fall in the range 101‐102 M−1s−1, depending on the substituted group of the catechols. The reaction for the oxidation of rutin and taxifolin also has been carried out and the oxidation went to the catechol ring of the flavonoids. The kinetic results show that the conjugation between pyrone and catechol rings plays an important role in the reactivity of the flavonoids.
Computer Simulation of n‐Butylamine‐Intercalated α‐Zirconium Phosphate
Authors: Chen Ruo‐Yu , Zhong Jing , Gu Chi‐Ruei , Chen Cheng‐Lung 
Published: May 2015

AbstractMolecular dynamics simulation was carried out to study the structure properties of α‐Zirconium Phosphate (α‐ZrP) loaded with n‐butylamine molecules. Two minimum‐energy configurations of α‐ZrP with interlayer distances 12.7 and 17.0 Å were found from the simulation. The structure properties of n‐butylmine, α‐ZrP and also interaction between n‐butylamine and α‐ZrP were analyzed. The different phase behavior was found due to the different strength of interaction between NH2 in n‐butylamine and O in PO4 of α‐ZrP.
Formation and Structural Characterization of Cobalt Titanate Thin Films
Authors: Chuang Shiow‐Huey , Gao Reui‐Hong , Gao Kuo‐Hsing , Chiang Michael Y. , Chao Tien‐Sheng 
Published: May 2015

AbstractThis research successfully produces high quality cobalt titanate (CoTiO3) thin films, a high‐k material for gate dielectrics, on SiO2/Si(100) substrates via a spin‐coating method with a sol‐like precursor solution. This study prepares the precursor solution by reactions of cobalt acetate and titanium isopropoxide in 2‐methoxyethanol. The current work obtains CoTiO3 thin films after spin coating followed by post‐treatment with air under 550∼650 °C. A scanning electron microscope, determines film thickness and morphology and X‐ray diffraction identifies material structures. This study uses X‐ray photoelectron spectroscopy to analyze both elemental compositions and chemical bonding characters of the thin films. This work also investigates reaction pathways.
Electrocatalytic Oxidation of Hydrogen Peroxide Using Iodide as Mediator; Application for its Simple and Selective Determination
Authors: Ojania Reza , Raoof Jahan‐Bakhsh , Babazadeh Roghaieh 
Published: May 2015

AbstractThe electrocatalytic oxidation of hydrogen peroxide has been studied by iodide at the surface of carbon paste electrode. Cyclic voltammetry and chronoamperometry techniques were used to investigate the suitability of iodide as a mediator for the electrocatalytic oxidation of hydrogen peroxide in aqueous solution with various pH. Results showed that pH 8.00 is the most suitable for this purpose. The kinetic process of the catalytic reaction can be explained using cyclic voltammetry and chronoamperometry. The calculated mean value of catalytic rate constant (kh) is determined to be 6.46 × 102 M−1s−1 using chronoamperometry data. In order to obtain the diffusion coefficient of iodide, chronoamperometry method has been used, that the value of D has been calculated 7.16 × 10−1 cm2 s−1. The catalytic oxidation peak current was linearly dependent on the hydrogen peroxide concentration and the linearity range obtained was 1.00 × 10−5 to 1.00 × 10−3 M. Detection limit has been found to be 5.61 × 10−6 M (3σ;). This method can provide a simple and low cost electrochemical sensor for catalytic oxidation detection of hydrogen peroxide in real sample.