bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Phenyl‐ and Methyl‐Substituents on p‐Phenylenediamine, an Electrochemical and Spectral Study
Authors: Chung Yi‐Chun , Su Yuhlong Oliver 
Published: May 2015

AbstractTwo series of substituted p‐phenylenediamines have been studied for their electronic effects on redox potential and spectral properties. p‐Phenylenediamines and N,N,N′,N”‐tetramethyl‐p‐phenylenediamine substituted with different numbers of phenyl groups have been synthesized and their cyclic voltammograms have been obtained. The correlation between the substituent number and the redox potential appears linear. The slope reflects the additive effect of electron‐donating methyl and electron‐withdrawing phenyl groups. The absorption spectra of the cation radicals indicate that phenyl‐substituted ones have broad intervalence‐charge transfer bands. The p‐phenylenediamines exhibit different properties from triphenylamines in that the oxidized forms are more stable in CH3CN then those in CH2Cl2. Some of the cation radicals or dications could undergo follow‐up chemical reactions and form products that are more easily oxidized.
Determination of Nitrofuran Residues in Tilapia Tissue by Enzyme‐Linked Immunosorbent Assay and Confirmation by Liquid Chromatography Tandem Mass Spectrometric Detection
Authors: Tsai Chung‐Wei , Hsu Chi‐Hsin , Wang Wei‐Hsien 
Published: May 2015

AbstractFurazolidone is a broad‐spectrum antibiotic that is frequently used in aquaculture on account of its excellent antibacterial properties. In this study, both the enzyme‐linked immunosorbent assay (ELISA) and high‐performance liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) methods were used to analyze the content of residual 3‐amino‐2‐oxazolidinone (AOZ), a metabolite of furazolidone in Tilapia tissue. Homogenized fish samples were spiked with various amounts of AOZ, and following combined acid‐hydrolysis and derivatization of the homogenized tissue with 2‐NBA (2‐nitrobenzaldehyde), sample clean‐up was performed and the derived 2‐nitrophenylmethylene‐3‐amino‐2‐oxazolidinone (NPAOZ) was analyzed. Using the LC‐MS/MS method, a linear correlation between measured concentration Y and spiked concentration × was observed: Y = 0.4518X − 0.0166, R2 = 0.9972. The linear equation for the ELISA method was Y = 0.9322X + 0.5168, R2 = 0.9066. These results demonstrated that the ELISA method might overestimate the residual AOZ content at low concentrations. The detection limit and recovery of the known addition were 0.05 μg kg−1a and 108% for the LC‐MS/MS method and 0.31 μg kg−1 and 305% for the ELISA method, respectively.
Palaeophytochemical Components from the Miocene‐Fossil Wood of Pinus Griffithii
Authors: Luo Jian‐Rong , Ma Qing‐Yun , Zhao You‐Xing , Yi Tie‐Mei , Li Cheng‐Sen , Zhou Jun 
Published: May 2015

AbstractSome Miocene‐fossil wood of Pinus griffithii preserved as lignified wood in brown coal was found in an open coalmine in Xundian of Yunnan Province, China. To explore its chemical components, here we show the palaeophytochemical investigation of this Pliocene‐fossil wood of P. armandii, resulting in the isolation of 11 compounds (1–11) including one new compound named 3,3‐dimethoxy‐24‐ethyl‐cholestan (1) by liquid column chromatography. Furthermore, sixteen volatiles were detected from this fossil wood by gas chromatography‐mass spectrometry (GC‐MS). These structures of 11 compounds were elucidated by analysis of their MS, 1D and 2D‐NMR spectra, and comparison with published data.
Unexpected Spiroproducts from the Reaction of N‐Benzoylglycine with Ortho‐Formylbenzoic Acids −3,5′‐Dioxo‐2′‐Phenyl‐1,3‐Dihydrospiro[Indene‐2,4′‐[1,3]Oxazol]‐1‐yl Acetates: Establishments of Their Structure
Authors: Younesi Aryan , Sorotskaya Ludmila N. , Krapivin Gennady D. 
Published: May 2015

AbstractThis paper describes a method of preparation of new 3,5′‐dioxo‐2′‐phenyl‐1,3‐dihydrospiro[indene‐2,4′‐[1,3]oxazol]‐1‐yl acetate and its 5‐chloro‐ and bromoderivatives as products of interaction of N‐benzoylglycine (hippuric acid) with corresponding ortho‐formylbenzoic acids. The reaction carried out in acetic anhydride media in the presence of piperidine as catalyst. The novel spirocompounds were purified by column chromatography from multicomponent reaction mixtures. The composition of the spiro‐products was confirmed by C, H, N element analysis. The structure was established by IR, MS, 1H‐ and 13C‐NMR analysis including COSY 1H‐13C experiments.
Chemotaxonomically Important Volatiles of the Genus Anthemis L. – a Detailed GC and GC/MS Analyses of Anthemis Segetalis Ten. from Montenegro
Authors: Radulović Niko S. , Blagojević Polina D. , Zlatković Bojan K. , Palić Radosav M. 
Published: May 2015

AbstractAlthough there are more than two hundred taxa in the pharmacologically important genus Anthemis, essential oil composition is known only for a small number of them. This is the first report on the volatiles of A. segetalis Ten. GC and GC/MS analyses of the essential oil hydrodistilled from A. segetalis aerial parts enabled the identification of 155 constituents, representing 92.4% of the total oil. Major constituents of the oil were sabinene (19.5%), germacrene D (12.6%), terpinen‐4‐ol (6.2%) and 1,8‐cineole (6.1%). Monoterpenoids (49.9%, especially those of thujane and p‐menthane skeletons) and sesquiterpenoids (39.4%, predominantly those of germacrane‐, cadinane‐ and caryophyllane‐types) were found to be the most abundant compound classes. The comparison of the essential oil composition of other Anthemis species with the present one was used as an additional tool for the clarification of infrageneric relationships. The results support the treatment of Anthemis subg. Cota as a separate genus.
1‐Butyl‐3‐methylimidazolium Hydrogen Sulfate [Bmim]HSO4: An Efficient Reusable Acidic Ionic Liquid for the Synthesis of 1,8‐Dioxo‐Octahydroxanthenes
Authors: Niknam Khodabakhsh , Damya Maryam 
Published: May 2015

Abstract1‐Butyl‐3‐methylimidazolium hydrogen sulfate [bmim]HSO4 as an acidic ionic liquid was prepared and used as a catalyst for the synthesis of 1,8‐dioxo‐octahydroxanthenes in excellent yields and short reaction times at 80 °C. The ionic liquid was easily separated from the reaction mixture by water extraction and was recycled four times without any loss in activity.
Half‐Sandwich and Triangular‐Sandwich Supramolecular Solid State Structures of C60 with Ir(ttp)Me
Authors: Song Xu , Chan Kin‐Shing 
Published: May 2015

AbstractNovel C60‐Ir(ttp)Me complexes with 1:1, 2:1 and 3:1 Ir(ttp)Me:C60 stoichiometries were synthesized with the 1:1 and 3:1 structures crytallographically characterized.
Hypervalent Iodine(III) Sulfonate Mediated Synthesis of Quinoxalines in Liquid PEG‐400
Authors: Lin Pei‐Ying , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching 
Published: May 2015

AbstractPEG‐400[poly(ethylene glycol‐400)] is used as a “green” recyclable solvent in the one‐pot synthesis of quinoxalines by reaction with aryl ketones, hypervalent Iodine(III) Sulfonate, and o‐phenylenediamines. Significant rate enhancements and improved yields have been observed.
Detection of Hydrogen Peroxide and Glucose Based on Immobilized C60‐Catalase Enzyme
Authors: Chuang Chia‐Wen , Luo Li‐Yung , Chang Ming‐Sen , Shih Jeng‐Shong 
Published: May 2015

AbstractThe interaction between fullerene C60 and catalase enzyme was studied with a fullerene C60‐coated piezoelectric (PZ) quartz crystal sensor. The partially irreversible response of the C60‐coated PZ crystal sensor for catalase was observed by the desorption study, which implied that C60 could chemically react with catalase. Thus, immobilized fullerene C60‐catalase enzyme was synthesized and applied in determining hydrogen peroxide in aqueous solutions. An oxygen electrode detector with the immobilized C60‐catalase was also employed to detect oxygen, a product of the hydrolysis of hydrogen peroxide which was catalyzed by the C60‐catalase. The oxygen electrode/C60‐catalase detection system exhibited linear responses to the concentration of hydrogen peroxide and amount of immobilized C60‐catalase enzyme that was used. The effects of pH and temperature on the activity of the immobilized C60‐catalase enzyme were also investigated. Optimum pH at 7.0 and optimum temperature at 25 °C for activity of the insoluble immobilized C60‐catalase enzyme were found. The immobilized C60‐catalase enzyme could be reused with good repeatability of the activity. The lifetime of the immobilized C60‐catalase enzyme was long enough with an activity of 93% after 95 days. The immobilized C60‐catalase enzyme was also applied in determining glucose which was oxidized with glucose oxidase resulting in producing hydrogen peroxide, followed by detecting hydrogen peroxide with the oxygen electrode/C60‐catalase detection system.
Anodic Stripping Voltammetric Determination of Mercury(II) in Water Using a 4‐Tert‐Butyl‐1‐(Ethoxycarbonylmethoxy)Thiacalix[4]Arene Modified Glassy Carbon Electrode
Authors: Wang Fei , Liu Jian , Wu Yan‐Ju , Gao Yu‐Mei , Huang Xu‐Feng 
Published: May 2015

AbstractA glassy carbon electrode coated the film of 4‐tert‐butyl‐1‐(ethoxycarbonylmethoxy)thiacalix[4]arene is designed for the determination of trace amounts of Hg2+. Compared with bare glassy carbon electrode, the modified electrode can improve the measuring sensitivity of Hg2+. Under the optimum experimental condition, the modified electrode in 0.1 mol L−1 H2SO4 + 0.01 mol L−1 KCl solution shows a linear voltammetric response in the range of 8.0 × 10−9 ∼ 3.0 × 10−6 mol L−1 with detection limit 5.0 × 10−9 mol L−1 for Hg2+. The high sensitivity, selectivity, and stability of modified electrode also prove its practical application for a simple, rapid and economical determination of Hg2+ in water samples.
Determination of Fluorescent Whitening Agents in Infant Clothes and Paper Materials by Ion‐Pair Chromatography and Fluorescence Detection
Authors: Shu Wei‐Chuan , Ding Wang‐Hsien 
Published: May 2015

AbstractA simple and rapid method was developed to simultaneously determine four stilbene‐type disulfonate and one distyrylbiphenyl‐type fluorescent whitening agents (FWAs) in infant clothes and paper materials by ion‐pair chromatography. FWAs were extracted from cloth and papers samples using a hot‐water extraction. The aqueous extract was then mixed with ion‐pair reagent, extracted with C18‐SPE cartridges and eluted with methanol. The contents of FWAs were determined by an isocratic ion‐pair chromatography with RP‐C18 column and equipped with fluorescence detection. Limits of quantitation were 0.04 to 0.45 ng/g in 10 g of samples. Recovery of FWAs in spiked infant cloth and paper samples was between 76 to 92% and precision (RSD) ranging from 2.0 to 4.0%. Analysis of three infant clothes and six paper materials found concentrations of selected FWAs ranging between n.d. to 24 μg/g and n.d. to 3.8 μg/g, respectively.
Expression, Purification and Characterization of Human α‐l‐Fucosidase
Authors: Liu Sheng‐Wen , Li Yaw‐Kuen 
Published: May 2015

Abstractα‐l‐Fucosidases (EC 3.2.1.51) are exo‐glycosidases. On the basis of the multi‐alignment of amino acid sequence, α‐l‐fucosidases were classified into two families of glycoside hydrolases, GH‐29 and GH‐95. They are responsible for the removal of l‐fucosyl residues from the non‐reducing end of glycoconjugates. Deficiency of α‐l‐fucosidase results in Fucosidosis due to the accumulation of fucose‐containing glycolipids, glycoproteins and oligosaccharides in various tissues. Recent studies discovered that the fucosylation levels are increased on the membrane surfaces of many carcinomas, indicating the biological function of α‐l‐fucosidases may relate to this abnormal cell physiology. Although the gene of human α‐l‐fucosidase (h‐fuc) was cloned, the recombinant enzyme has rarely been overexpressed as a soluble and active from. We report herein that, with carefully control on the growing condition, an active human α‐l‐fucosidases (h‐Fuc) was successfully expressed in Escherichia coli for the first time. After a series steps of ion‐exchange and gel‐filtration chromatographic purification, the recombinant h‐Fuc with 95% homogeneity was obtained. The molecular weight of the enzyme was analyzed by SDS‐PAGE (∼50 kDa) and confirmed by ESI mass (50895 Da). The recombinant h‐Fuc was stable up to 55 °C with incubation at pH 6.8 for 2 h; the optimum temperature for h‐Fuc is approximately 55 °C. The enzyme was stable at pH 2.5–7.0 for 2 h; the enzyme activity decreased greatly for pH greater than 8.0 or less than 2.0. The Km and kcat values of the recombinant h‐Fuc (at pH 6.8) were determined to be 0.28 mM and 17.1 s−1, respectively. The study of pH‐dependent activity showed that the recombinant enzyme exhibited optimum activity at two regions near at pH 4.5 and pH 6.5. These features of the recombinant h‐Fuc are comparable to the native enzyme purified directly from human liver. Studies on the transfucosylation and common intermediate of the enzymatic reaction by NMR support that h‐Fuc functions as a retaining enzyme catalyzing the hydrolysis of substrate via a two‐step, double displacement mechanism.
New Dioxa‐Cage and Diacetal Trioxa‐Cage Compounds
Authors: Lin Hui‐Chang , Wu Hsien‐Jen 
Published: May 2015

AbstractThe synthesis of new dioxa‐cage compound 8 and diacetal trioxa‐cage compound 17 has been accomplished from dicyclopentadiene in a short sequence. A preliminary study on the π‐facial selectivity of 17, which possesses a new rigid skeleton, is also reported.
Spectrophotometric Determination of Piroxicam via Chelation with Fe(III) in Commercial Dosage Forms
Authors: Azmi Syed Najmul Hejaz , Iqbal Bashir , Jaboob Muna Ahmed Mohad , Al Shahari Warda Ali Said , Rahman Nafisur 
Published: May 2015

AbstractThe objective of this work is to develop and validate spectrophotometric method for the determination of piroxicam in commercial dosage forms. The method is based on the chelation of the drug with Fe(III) to form pink coloured metal chelate at room temperature which absorbs maximally at 504 nm. Beer's law is obeyed over the concentration range of 8–160 μg mL−1 (A = 1.07 × 10−3 + 7.75 × 10−3 C). Under the optimized experimental conditions, proposed method is validated as per the International Conference on Harmonisation guidelines. The limits of detection and quantitation for the proposed method are 0.775 and 2.348 μg mL−1, respectively. The proposed method has been successfully applied to the determination of piroxicam in commercial dosage forms. The results are compared with the reference El‐Ries et al. spectrophotometric method.
Effect of Li2O Addition on the Preparation of (Y2‐yLiy)Ti2O7‐y
Authors: Su Wen‐Ping , Lee Yu‐Hsuen , Hsieh Ching‐Tien , Sheu Hwo‐Shuenn , Lee Jyh‐Fu , Chiang Yong‐Ping , Kao H.‐C. I. 
Published: May 2015

AbstractA new series of (Y2‐yLiy)Ti2O7‐y having an ordered pyrochlore phase was prepared by a solid state reaction method with a solid solution range of 0.05 ≥ y ≥ 0.10. Unit cell parameters obtained by the Rietveld refinement method shows that the a‐axis decreases linearly with increasing the amount of Li ion addition, indicating the successful incorporation of the Li ion into unit cell. The average x‐fractional coordinate of the O(1) site depends on the ionic radius ratio of r(A3+)/r(Ti4+) in the A2Ti2O7 with a pyrochlore phase. The Ti K‐edge XANES spectra of the (Y2‐yLiy)Ti2O7‐y show that the valence of the Ti ions is slightly less than 4 so that Ti is in the mixed valence state. Average particle size increases with increasing the amount of extra Li ion addition, which acts as a flux to lower the melting point of the materials.
A Novel Method for Uric Acid Determination Using CdS Quantum Dots as Fluorescence Probes
Authors: Han Su‐Qin , Zhao Shou‐Miao 
Published: May 2015

AbstractA novel method has been developed for uric acid analysis based on the quenching of fluorescence emission from CdS quantum dots by uric acid. Also, the effect of the presence of different surfactant agents, in order to improve the fluorescent signals of the CdS QDs, has been investigated, and the cetyltrimethyl ammonium bromide (CTAB) was selected. Under optimum conditions, the calibration graph was linear over the range of 0.1 ng/mL to 12.0 ng/mL (r = 0.9950). The limit of detection (S/N = 3) was 0.1 ng/mL. The RSD for ten determinations of 5.0 ng/mL uric acid was 3.5%. The method was applied to determine uric acid in human serum and urine sample with satisfactory results.
Syntheses, Structures and Luminescent Properties of Metal Halide Complexes Containing 2,3‐Diphenylquinoxaline
Authors: Yeh Chun‐Wei , Ray Umasankar , Chen Jhy‐Der 
Published: May 2015

AbstractThe reaction of CuI with 2,3‐diphenylquinoxaline (L) in 1:1 mole proportion in CH3CN/THF afforded the dinuclear complex [CuI(L)]2, 1, whereas the reactions of MX2 (M = Cu; Hg) with L in 1:2 mole proportion in CH3OH gave the mononuclear complexes CuX2(L)2 (X = Cl, 2; Br, 3) and HgX2(L)2 (X = Cl, 4; Br, 5). Formulations of all the complexes were determined on the basis of X‐ray crystallography, elemental, IR‐ and emission spectroscopy. X‐ray examination revealed that complex 1 forms the μ,μ‐iodobridged dimer with distorted trigonal planar geometry through coordination of L ligand by one nitrogen atom to the Cu(I) center. The metal centers of complexes 2 and 3 form distorted square planar geometry while those of complexes 4 and 5 form linear geometry. The molecules of these complexes are interlinked through C‐H—π and/or π‐π stacking and anion—π interactions that form the packed structure. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π r̊ π* transitions.
Effect of Manganese Dioxide Dispersion on the Absorbing Properties of Manganese Dioxide (MnO2)‐Epoxy Composites
Authors: Ting Tzu‐Hao 
Published: May 2015

AbstractManganese dioxide (MnO2) particle was synthesized and introduced into epoxy resin to be microwave absorber. The spectroscopic characterization of the formation processes of MnO2 was studied by using X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Microwave absorbing properties with different volume fractions of MnO2 were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2–18 and 18–40 GHz microwave frequency range using the free space method. The absorbing performance of MnO2‐epoxy composites at same sample thickness and at various sample thickness were also studied. It was found that the best absorbing property and an absorption frequency range shifting could be obtained at the frequency range of 2–18 and 18–40 GHz.
Hybrid Silver Nanowire/Titanium Oxides Nanocomposites as Anode for Dye‐Sensitized Solar Cell Application
Authors: Chen Tsan‐Yao , Fan Chia‐Ming , Wu Jun‐Yi , Lin Tsang‐Lang 
Published: May 2015

AbstractIn this study, we investigated the effect of adding metallic nanowires in the anode of dye‐sensitized solar cell (DSSC) to improve the photovoltaic efficiency. Photo‐excited electrons can be efficiently transferred to the electrode through the network of the dispersed metallic nanowires added in the anode. We compared the photovoltaic performance with the anodes of standard P‐25, the silver nanowire/P‐25, and the TiO2 coated silver nanowire/P‐25 DSSC. The DSSC with TiO2 coated silver nanowires shows significantly improved (about 1.5 and 2.0 times) photovoltaic efficiency and structural durability compared with that of the standard P‐25 and the silver nanowires without coating DSSC. The TiO2 coated silver nanowire can resist the redox chemical corrosions by iodide ions since they are protected from contact with electrolytes during the photovoltaic reaction by the coated thin TiO2 layer. The presence of the metal network (silver nanowires) improves the production and transportation of light generated current so as to the photovoltaic efficiency.
Comparison of Volatile Organic Compounds of Thymus Vulgaris Using Hydrodistillation and Headspace Solid Phase Microextraction Gas Chromatography Mass Spectrometry
Authors: Nezhadali Azizollah , Akbarpour Mina , Shirvan Batool Zarrabi , Mousavi Mehdi 
Published: May 2015

AbstractEssential oil of aerial parts of Tymus vulgaris L. from Babaaman montains of Iran were isolated by hydrodistillation with an average oil yield 1.9 w/w%. The components of the oil were identified by gas chromatography mass spectrometry. On a separate experiments the compositions of volatile emission of the plant were studied by headspace solid phase microextraction and gas chromatography mass spectrometry. The tempratures used during the sample preparation were 25°C and 50°C. In order to determine the effect of solvent (water) on the separation, the experiments were done in the presence and absence of distilled water in the extraction vial at the tempratures mentioned above. Ten majour components were obtained in four different experimental headspace solid phase microextraction conditions and the hydrodistillation methods from the plant. Thymol was found to be the most abundant costituent (27.2–73.09%), follwoed by p‐cymene (6.86–31.76%), γ‐terpinene (1.02–9.26%), myrcene (0.05–8.84%), α‐pinene (0.25–6.63%), caryophyllene (3.09–5.56%), thymol methyl ether (0.99–2.97%), thymolacetate (0.11–2.05%), carvacrol (0.49–1.70%) and α‐cadinol (0.38–1.10%).
Adsorption Behavior of Metal Cations on Gold Nanoparticle Surfaces Studied by Isothermal Titration Microcalorimetry
Authors: Xu Bin 
Published: May 2015

AbstractThe adsorption behavior of metal cations on gold nanoparticles was investigated by isothermal titration microcalorimetry (ITC) for the first time, and verified by transmission electron microscopy (TEM), and UV absorption spectroscopy. When transition metal cations were injected into the gold colloids, a binding isotherm with a sigmoidal response was obtained; and when instead of alkaline earth cations, the binding isotherm changed from the overall exothermic to endothermic nature. The binding enthalpy depends on the nature and concentration of added cations. The interactions of metal cations with the surface gold atoms and the COO− group of citrate salt that weakly bound on gold nanoparticles are the driving force for the binding; and the binding process is enthalpically driven. TEM images indicate that the addition of metal cations results in the growth and aggregation of gold nanoparticles. After the metal cations were added to the gold colloids, the intensity of the surface plasmon resonance adsorption band at 523 nm of gold nanoparticles decreased, and a new absorption at around 610 nm appeared. This is attributed to gold nanoclusters induced by the surface binding of the metal cations on gold nanoparticles, which is further confirmed by ITC results.