bluuebunny/crossref_metadata_2025 huggingface dataset:
Zeolite Nanoparticle Modified Carbon Paste Electrode as a Biosensor for Simultaneous Determination of Dopamine and Tryptophan
Authors: Balal Khalilzadeh , Mohammad Hasanzadeh , Bahareh Bakhoday , Ali Babaei , Maryam Hajjizadeh , Mozhgan Zendehdel
Published: May 2015

A new chemically modified electrode is constructed based on an iron(III) doped zeolite modified carbon paste electrode (Fe3+Y/ZCME). The electrode was evaluated as a sensor for sub‐micromolar determination of tryptophan (Trp) and dopamine (DA). The measurements were carried out using the differential pulse voltammetry (DPV) method in a phosphate buffer solution with pH = 5. The prepared modified electrode shows voltametric responses with high sensitivity and stability for DA and Trp in optimal conditions. The analytical performance of this sensor has been evaluated for detection of DA and Trp in human serum.
Chloroferrate(III) Ionic Liquid as Recyclable Catalyst for the Acetylation of Alcohols and Phenols and for 1,1‐Diacylation of Aldehydes
Authors: Wang Dong‐Sheng , Li Gui‐Yun , Peng Yan‐Qing
Published: May 2015

A Lewis acidic ionic liquid, [bmim][FeCl4], was employed to catalyze acetylation of alcohols and phenols, and the conversion of aldehydes to corresponding 1,1‐diacetates without conventional organic solvents. The catalyst is easily available, water‐tolerant, recoverable and easy to handle.
Vapour Phase Hydrogenation of Cinnamaldehyde over Nano Ni and Ni/SiMCM‐41 Catalysts
Authors: Jao Kuang‐Yu , Liu Kang‐Wen , Yang You‐Hsiang , Ko An‐Nan
Published: May 2015

Ni nanoparticles (Ni(1) and Ni(2)) and Ni loaded SiMCM‐41 (15Ni/SiMCM‐41) were prepared and characterized with XRD, TEM, N2 adsorption, CO chemisorption, and H2‐TPR. The Ni specific surface area followed the order of 15Ni/SiMCM‐41 > Ni(1) >> Ni(2), whereas the Ni particle size exhibited the opposite trend. These catalysts were utilized for vapour phase hydrogenation of cinnamaldehyde at 1 atm and 200 °C in a fixed‐bed, down flow reactor. The main products include hydrocinnamaldehyde, styrene, ethylbenzene, and 2‐phenyl‐1‐propanol. The catalytic activity decreased in the same order as that of Ni specific surface areas. The SiMCM‐41 support possessed very large surface area, leading to enhanced dispersion and specific surface area of Ni nanoparticles. As a result, the 15Ni/SiMCM‐41 catalyst exhibited the highest activity. Based on the investigation of reaction pathways, it is important to emphasize that both hydrogenation and hydroelimination of formaldehyde (hydrodeformylation) occur in the vapour phase reaction.
Solution Structure and Model Membrane Interactions of P‐113, a Clinically Active Antimicrobial Peptide Derived from Human Saliva
Authors: Yip Bak‐Sau , Chen Heng‐Li , Cheng Hsi‐Tsung , Wu Jiun‐Ming , Cheng Jya‐Wei
Published: May 2015

P‐113, AKRHHGYKRKFH‐NH2, was derived from human saliva and found to possess clinical activity against fungus infections in HIV patients with oral candidiasis. We have determined the solution structure of P‐113 bound to membrane‐mimetic SDS micelles by two‐dimensional NMR methods. The SDS micelle‐bound structure of P‐113 adopts an α‐helical segment and the positively charged residues are clustered together to form a hydrophilic patch. A variety of biophysical and biochemical experiments, including circular dichroism, fluorescence spectroscopy and microcalorimetry, were used to show that P‐113 interacted with negatively charged phospholipid vesicles and induced dye release from these vesicles. However, its dye leakage efficiency is much less than the results of previously reported antimicrobial peptides. These results suggest that the antimicrobial activity of P‐113, unlike other antimicrobial peptides, may act not only through binding to and destabilization of the microbial membrane but also through a specific protein receptor on the microbial cell surface.
Cyanoacetanilides Intermediates in Heterocyclic Synthesis. Part 5: Preparation of Hitherto Unknown 5‐Aminopyrazole and Pyrazolo[1,5‐a]pyrimidine Derivatives Containing Sulfamoyl Moiety
Authors: Ammar Yousry A. , Aly Mohsen M. , Al‐Sehemi Abd Allah G. , Salem Mohamed A. , El‐Gaby Mohamed S. A.
Published: May 2015

Novel 5‐aminopyrazole and pyrazolo[1,5‐a]pyrimidine derivatives have been synthesized from the readily accessible cyanoacetanilide derivative (2).
Synthesis and Structure Analysis of Aurivillius Phases Pb1‐xBi4‐+Ti1‐xMnxO15
Authors: Zulhadjri  , Prijamboedi B. , Nugroho A. A. , Ismunandar
Published: May 2015

Synthesis 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

Stable 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

Steric 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

A 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

A 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

The 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

A 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

In 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

The 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

Nanoflakes 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

The 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

Remarkable 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

White 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

In 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

1‐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

A 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

A 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

The 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

Molecular 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

This 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

The 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.
Electrochemical Oxidation of Cytosine on Carbon Paste Electrode and Its Determination
Authors: Ruan Cheng‐Xiang , Lou Jin , Duan Yuan‐Yuan , Sun Wei
Published: May 2015

In this paper electrochemical oxidation of cytosine was investigated on a carbon paste electrode for the first time. In pH 5.0 Britton‐Robinson (B‐R) buffer solution a well‐define irreversible oxidation peak appeared at the potential of 1.480 V (vs. SCE), which indicated the electrooxidation of cytosine on the electrode. The electrochemical behaviors of cytosine were carefully investigated by cyclic voltammetry at the selected conditions. The electrochemical parameters such as electron transfer number (n), electron transfer coefficient (α) and electrode reaction standard rate constant (ks) was calculated with the results as 2.14, 0.15 and 1.049 × 10−3 s−1, respectively. Under the optimal conditions a good linear relationship was constructed between the cytosine concentration and the differential pulse voltammetric current in the range from 10.0 to 1000.0 μmol/L with the linear regression equation as Ip(μA) = 0.0519C (μmol/L) + 0.419 (γ = 0.999) and the detection limit as 1.9 μmol/L (3σ;).
Fabrication of Cetyltrimethylammonium Bromide/chitosan Modified Glassy Carbon Electrode for Simultaneous Determination of Uric Acid and Ascorbic Acid
Authors: Zhang Ying , Luo Li‐Qiang , Ding Ya‐Ping , Li Qiu‐Xia , Shen Xia
Published: May 2015

The electrochemical behavior of uric acid (UA) and ascorbic acid (AA) on the surface of the cetyltrimethylammonium bromide (CTAB) incorporating chitosan film‐modified glassy carbon electrode (GCE) was investigated by linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The modified electrode could completely separate the common merged voltammetric signals of UA and AA for 204 mV. Under the optimum conditions, the anodic peak currents of DPV were proportional to the concentration of AA in the range of 2.0 to 800.0 μM, and that of UA in the range of 0.5 to 200.0 μM. The proposed method was used to detect UA in urine with a satisfactory result.
A Validated RP HPLC Method for Estimation of Almotriptan Malate in Pharmaceutical Dosage Form
Authors: Suneetha A. , Syama B. Sundar
Published: May 2015

An accurate, sensitive, precise and robust reverse phase high performance liquid chromatographic method for the estimation of almotriptan malate in pharmaceutical dosage form has been developed and validated. Chromatographic separation was conducted on Phenomenex Gemini C18 (250 mm × 4.6 mm, 5μ) column at room temperature using potassium dihydrogen phosphate buffer: acetonitrile (80:20) as a mobile phase, pH adjusted to 3.2 ± 0.1 with 10% sodium hydroxide and at a flow rate of 1.5 mL min−1, while UV detection was performed at 227 nm. The retention time for almotriptan malatewas found to be 9.47 ± 0.05 min. The method was found to be linear in the range of 1.0–10.0 μg mL−1. The limit of detection and quantitation for almotriptan malate were found to be 0.03 and 0.1 μg mL−1, respectively. Analytical recovery was > 99.87%. The method was validated stastically and applied for the quantitative analysis of almotriptan malate in bulk and formulations.
New Ruthenium(II) Polypyridyl‐Type Complexes with Oxadiazole Derivative Ligand
Authors: Lin Chien‐Ho , Kao Hsien‐Chang , Hsu Chia‐Jung , Wang Wen‐Jwu
Published: May 2015

A new ruthenium complex, [Ru(L)(bpy)2]ṁ2PF6, (L = 3,5‐di(2ṁ‐pyridyl)‐1,2,4‐oxadiazole), was synthesized and characterized. The assignment of chemical shift for [Ru(L)(bpy)2]ṁ2PF6 was accomplished by HHCOSY technique. The cyclic voltammogram of [Ru(L)(bpy)2]ṁ2PF6 shows a metal‐centered RuII/RuII oxidation with potential at 1.35 V, as well as four reversible reduction waves with the former two potentials at −1.24 and −1.60 V, attributed to two bpy/bpy− process, and the latter two potentials at −1.86 and −2.16 V, attributed to L/L− and L−/L2−, respectively. The absorption spectrum of the ruthenium complex was dominated by metal‐to‐ligand charge transfer (MLCT) band in the visible range, with absorption maxima appearing at 442 nm and molar extinction coefficient of 13 × 103 M−1cm−1. The phosphorescent emission band has been attributed to from MLCT triplet state.
Electronic Structure of Anthocyanidins Adsorbed on Buckminsterfullerene: First Principles Studies
Authors: Su Yen Hsun , Wu Yang‐Kai , Hsue Young‐Chung
Published: May 2015

The efficiency of photoelectric conversion for environmentally‐friendly green solar cell, such as anthocyanidins‐sensitized solar cell, is low. Recently, fullerene‐based solar cell is used to improve efficiency of photo‐electric conversion. The evaluation of formation for the buckminsterfullerene (C60)‐anthocyanins system is desired. We use an inexpensive and low‐cost method tool, density functional theory, to study the buckminsterfullerene (C60)‐ anthocyanidins system. We found formation energy of C60 adsorbing anthocyanidins is ranged from −0.61 eV to −2.42 eV. Thus, compound of C60 and anthocyanidins may be synthesized by arc or laser power under reduction atmosphere. These phenomenons will have a potential to apply in the evaluation and database of anthocyanidins‐sensitized fullerene‐based solar cell.
Platinum Nanoparticles on Flexible Carbon Fiber Paper without Transparent Conducting Oxide Glass as Counter Electrode for Dye‐Sensitized Solar Cells
Authors: Lan Jo‐Lin , Feng Hsien‐Ping , Wei Tzu‐Chien , Peng Chao , Cheng Hai‐Peng , Chen Wen‐Hsiang , Chang Ya‐Huei , Hsu Wen‐Chi , Wan Chi‐Chao
Published: May 2015

Flexible carbon fiber paper deposited with platinum nanoparticles was applied as counter electrode for dye‐sensitized solar cells (DSSCs). Compared to others, such as sputtered‐Pt or PVP‐capped Pt nanoparticles on TCO glass, not only does this counter electrode has good conductivity without using TCO glass but also flexible and shows good adhesion. Acceptable charge‐transfer resistance of 5.25 Ω‐cm2 is obtained. Current‐voltage characteristics of the DSSC are 0.71 V on VOC, 9.44 mA/cm2 on JSC, 0.61 on FF and 4.13% cell efficiency under AM 1.5, 100 mW/cm2 illumination. Additionally, spinning technology can be applied to produce this low cost counter electrode.
Tetrabutylammonium Fluoride (TBAF) Catalysed Synthesis of 2‐Arylbenzimidazole in Water under Ultrasound Irradiation
Authors: Joshi Ratnadeep S. , Mandhane Priyanka G. , Dabhade Sanjay K. , Gill Charansingh H.
Published: May 2015

One‐pot multistep reactions involving a new environmentally friendly catalytic procedure have been developed for the synthesis of benzimidazole. The reaction of the substituted aldehyde with o‐phenylenediamine in water under ultrasonic irradiation at ambient temperature for appropriate time using 5 mol% of TBAF furnish the desired product in good to excellent yield. The process is green, mild, inexpensive, excellent chemo selectivity, and excellent yields are the main advantages of this procedure.
Ionic Liquid‐Hemoglobin‐Carbon Paste Composite Bioelectrode and Its Electrocatalytic Activity
Authors: Xuan Zong‐Wei , Sun Xiao‐Ying , Jiao Guo‐Song , Zhai Zi‐Qin , Sun Wei , Lu Lu‐De
Published: May 2015

A new carbon ionic liquid paste bioelectrode was fabricated by mixing hemoglobin (Hb) with graphite powder, ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF4) and liquid paraffin homogeneously. Nafion film was cast on the electrode surface to improve the stability of bioelectrode. Direct electrochemistry of Hb in the bioelectrode was carefully investigated. Cyclic voltammetric results indicated that a pair of well‐defined and quasi‐reversible electrochemical responses appeared in pH 7.0 phosphate buffer solution (PBS), indicating that direct electron transfer of Hb was realized in the modified electrode. The formal potential (E0′) was calculated as −0.316 V (vs. SCE), which was the typical characteristic of the electrochemical reaction of heme Fe(III)/Fe(II) redox couple. Based on the cyclic voltammetric results the electrochemical parameters of the electrode reaction were calculated. This bioelectrode showed high electrocatalytic activity towards the reduction of trichloroacetic acid (TCA) with good stability and reproducibility.
Thioglycolic Acid Capped CdS Quantum Dots as Fluorescence Probe for Ultrasensitive Determination of Tetracycline and Oxytetracycline
Authors: Zhao Shou‐Miao , Han Su‐Qin
Published: May 2015

Water soluble CdS quantum dots (QDs) have been synthesized using thioglycolic acid (TGA) as surface modifying agent through a one step process by using safe and low cost materials. These TGA capped CdS QDs are highly stable in aqueous solution and applied for ultrasensitive tetracycline (TC) and oxytetracycline (OTC) sensing. The approach was based on the fluorescence of the QDs selectively quenched in the presence of TC and OTC, respectively. Under optimal conditions, the relative fluorescence intensities of CdS QDs were decreased linearly with increasing TC and OTC in the range of 0.05 to 10.0 μM and 0.1 to 10.0 μM, respectively. The limit of detection (S/N = 3) was 5.0 nM for TC and 10.0 nM for OTC, respectively. The RSD for eleven determinations of 5.0 μM TC was 1.26% and 5.0 μM OTC was 0.8%, respectively. There was no significant wavelength shift on the fluorescence‐quenched signals in the presence of the drugs. The effect of common foreign substances on the fluorescence of the QDs was examined to evaluate the selectivity and the results showed a high selectivity of the TGA capped CdS QDs towards TC and OTC. The method presented here is simple, rapid, inexpensive, sensitive and suitable for practical application.
Sensitive and Simple Electrochemical Detection of Lead(II) with Carbon Ionic Liquid Electrode
Authors: Liu He‐Jian , Qu Li‐Ning , Hu Song , Zhan Tian‐Rong , Zhao Chao‐Zhi , Sun Wei
Published: May 2015

In this paper a carbon ionic liquid electrode (CILE) was fabricated by using ionic liquid 1‐ethyl‐3‐methylimidazolium ethylsulphate ([EMIM]EtOSO3) as the modifier and further used as the working electrode for the sensitive anodic stripping voltammetric detection of Pb2+. The characteristics of the CILE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In pH 4.5 NaAc‐HAc buffer Pb2+ was accumulated on the surface of CILE due to the extraction effect of IL and reduced at a negative potential (‐1.20 V). Then the reduced Pb was oxidized by differential pulse anodic stripping voltammetry with an obvious stripping peak appeared at −0.67 V. Under the optimal conditions Pb2+ could be detected in the concentration range from 1.0 × 10−8 mol/L to 1.0 × 10−6 mol/L with the linear regression equation as Ip(μA) = −0.103 C (μmol/L) + 0.0376 (γ = 0.999) and the detection limit as 3.0 × l0−9 mol/L (3σ). Interferences from other metal ions were investigated and Cd2+ could be simultaneously detected in the mixture solution. The proposed method was further applied to the trace levels of Pb2+ detection in water samples with satisfactory results.
Markov model for characterizing neuropsychologic impairment and Monte Carlo simulation for optimizing efavirenz therapy
Authors: Bisaso Kuteesa R. , Mukonzo Jackson K. , Ette Ene I.
Published: May 2015

The study was undertaken to develop a pharmacokinetic‐pharmacodynamic model to characterize efavirenz‐induced neuropsychologic impairment, given preexistent impairment, which can be used for the optimization of efavirenz therapy via Monte Carlo simulations. The modeling was performed with NONMEM 7.2. A 1‐compartment pharmacokinetic model was fitted to efavirenz concentration data from 196 Ugandan patients treated with a 600‐mg daily efavirenz dose. Pharmacokinetic parameters and area under the curve (AUC) were derived. Neuropsychologic evaluation of the patients was done at baseline and in week 2 of antiretroviral therapy. A discrete‐time 2‐state first‐order Markov model was developed to describe neuropsychologic impairment. Efavirenz AUC, day 3 efavirenz trough concentration, and female sex increased the probability (P01) of neuropsychologic impairment. Efavirenz oral clearance (CL/F) increased the probability (P10) of resolution of preexistent neuropsychologic impairment. The predictive performance of the reduced (final) model, given the data, incorporating AUC on P01and CL /F on P10, showed that the model adequately characterized the neuropsychologic impairment observed with efavirenz therapy. Simulations with the developed model predicted a 7% overall reduction in neuropsychologic impairment probability at 450 mg of efavirenz. We recommend a reduction in efavirenz dose from 600 to 450 mg, because the 450‐mg dose has been shown to produce sustained antiretroviral efficacy.
Hydrophobic charge‐induction resin with 5‐aminobenzimidazol as the functional ligand: preparation, protein adsorption and immunoglobulin G purification
Authors: Yan Jun , Zhang Qi‐Lei , Tong Hong‐Fei , Lin Dong‐Qiang , Yao Shan‐Jing
Published: May 2015

A new hydrophobic charge‐induction chromatography resin was prepared with 5‐aminobenzimidazol as functional ligand and polyacrylic ester beads as matrix. Adsorption isotherms and adsorption in columns were investigated using human immunoglobulin G and bovine serum albumin as model proteins, and the influence of pH and NaCl concentration was discussed. Results showed that the ligand density was 195 μmol/mL gel, and protein selectivity can be improved by controlling pH and salt addition. An optimized purification process (sample loading at pH 8.0 with 0.2 M NaCl and elution at pH 5.0) was performed to purify human immunoglobulin G from bovine serum albumin containing feedstock, which resulted in human immunoglobulin G purity of 99.7% and recovery of 94.6%. A similar process was applied for the purification of monoclonal antibody from cell culture supernatant, which showed antibody purity of 94.9% and recovery of 92.5%. The results indicated that the new resin developed had comparable performance as Protein A chromatography and would be suitable for antibody purification from complex feedstock.
Dual Enzyme‐Responsive Capsules of Hyaluronic Acid‐block‐Poly(Lactic Acid) for Sensing Bacterial Enzymes
Authors: Tücking Katrin‐Stephanie , Grützner Verena , Unger Ronald E. , Schönherr Holger
Published: May 2015

The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA‐block‐PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme‐responsive HYA‐b‐PLA is carried out by copper–catalyzed Huisgen 1,3‐dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering (DLS), and fluorescence lifetime imaging microscopy (FLIM). DLS measurements show that both enzymes cause a rapid decrease in the hydrodynamic diameter of the nanocapsules. Fluorescence spectroscopy data confirm the liberation of encapsulated dye, which indicates the disintegration of the capsules and validates the concept of enzymatically triggered payload release. Finally, cytotoxicity assays confirm that the HYA‐b‐PLA nanocapsules are biocompatible with primary human dermal microvascular endothelial cells.
A finite element method for modeling coupled flow and deformation in porous fractured media
Authors: Pouya Ahmad
Published: May 2015

Modeling the flow in highly fractured porous media by finite element method (FEM) has met two difficulties: mesh generation for fractured domains and a rigorous formulation of the flow problem accounting for fracture/matrix, fracture/fracture, and fracture/boundary fluid mass exchanges. Based on the recent theoretical progress for mass balance conditions in multifractured porous bodies, the governing equations for coupled flow and deformation in these bodies are first established in this paper. A weak formulation for this problem is then established allowing to build a FEM. Taking benefit from recent development of mesh‐generating tools for fractured media, this weak formulation has been implemented in a numerical code and applied to some typical problems of hydromechanical coupling in fractured porous media. It is shown that in this way, the FEM that has proved its efficiency to model hydromechanical phenomena in porous media is extended with all its performances (calculation time, couplings, and nonlinearities) to fractured porous media. Copyright © 2015 John Wiley & Sons, Ltd.
Abnormal functional connectivity in women with urgency urinary incontinence: Can we predict disease presence and severity in individual women using Rs‐fcMRI/
Authors: Nardos Rahel , Karstens Lisa , Carpenter Samuel , Aykes Kamari , Krisky Christine , Stevens Corrine , Gregory W.Thomas , Fair Damien A.
Published: May 2015

Aims

To identify atypical brain functional connectivity in women with UUI and detrusor overactivity (DO) and to predict the presence/severity of UUI in individual women using connectivity features.

Methods

This is a cross‐sectional study comparing brain functional connectivity in women with and without UUI. Validated symptom/quality of life questionnaires were used for phenotyping. Participants are females between ages 40 and 85 with daily UUI with DO (Cases, N = 16) and without UUI (Controls, N = 24). Functional MRI and Resting state connectivity MRI were obtained at empty/ full bladder. Multivariate pattern analysis (MVPA) was used to predict the presence and severity of UUI from connectivity data.

Results

There are significant differences in brain activation between cases and controls in eighteen brain regions irrespective of empty or full bladder. These include regions involved in attention (inferior partietal), decision making (inferior and superior frontal gyrus), primary motor and sensory (precentral and postcentral gyrus) functions. Women with UUI showed no change in connectivity with bladder filling in regions involved in interoception (insula), integration of afferent function (anterior cingulate), and decision making (middle frontal). MVPA of connectivity data showed robust classification of an individual woman as case or control (89% sensitivity, 83% specificity). Six connectivity features accurately predicted disease severity (R2 = 0.81).

Conclusion

We identified two mechanisms of abnormal bladder control, one involving atypical activation of brain regions, and another atypical functional integration across sensory, emotional, cognitive and motor regions. Connectivity information is robust enough to classify an individual as having UUI or not and to predict symptom severity. Neurourol. Urodynam. 35:564–573, 2016. © 2015 Wiley Periodicals, Inc.
Springende Hüpfgummis
Authors: Vollmer Michael , Möllmann Klaus‐Peter
Published: May 2015

Hüpfgummis sind einfache, preiswerte Spielzeuge, die in Spielwarenläden oder Science Centern erhältlich sind. Sie ermöglichen interessante Einblicke in physikalische Phänomene der Mechanik – insbesondere mit Hochgeschwindigkeits‐Videos.