bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversity of Chemical Constituents from Saxifraga Montana H.
Authors: Liu Jun‐Xi , Di Duo‐Long , Shi Yan‐Ping
Published: May 2015

A thorough phytochemical investigation of the whole plant of Saxifraga montana H. afforded a new glucoside, methyl 6″‐O‐(E)‐p‐hydroxycinnamoxyl‐glucosyringate (1), and seventeen known natural products, 3‐methyl‐6‐methoxy‐3,4‐dihydroisocoumarin‐8‐O‐β‐D‐glucospyranoside (2), gallic acid (3), glucosyringic acid (4), daphnoretin (5), chamaejasmoside (6), myricetin (7), quercetin (8), quercetin‐3‐O‐β‐D‐galactopyranoside (9), quercetin‐3‐O‐α‐L‐arabinoside (10), quercetin‐3‐O‐β‐D‐glucospyranoside (11), rutin (12), quercetin‐3‐O‐β‐D‐glucopyranosyl (6‐1) glucopyranoside (13), ursolic acid (14), 5,28‐stigmastadien‐3β‐ol (15), β‐sitosterol (16), β‐daucosterin (17), 6′‐palmitoxyl‐β‐daucosterin (18). On the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC and HMBC), FAB‐MS and HR‐ESI‐MS techniques, their structures were elucidated.
1H NMR, IR and UV/VIS Spectroscopic Studies of Some Schiff Bases Derived from 2‐Aminobenzothiazole and 2‐Amino‐3‐Hydroxypyridine
Authors: Issa Raafat M. , Khedr Abdalla M. , Rizk Helen
Published: May 2015

By condensing 2‐aminobenzothiazole with 2‐hydroxy‐1‐naphthaldehyde, 2‐hydroxybenzaldehyde, 4‐methoxybenzaldehyde, 4‐hydroxybenzal‐dehyde, benzaldehyde and 4‐dimethylaminobenzaldehyde, and five Schiff bases Ia‐Ie are prepared. Also, two Schiff bases IIa and IIb are prepared by condensation of 2‐amino‐3‐hydroxypyridine with 2‐hydroxy‐1‐naphthaldehyde and 2‐hydroxybenzaldehyde. The 1H NMR, IR and UV/Vis spectra of these seven Schiff bases are investigated. The signals of the 1H NMR spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular structure. The UV/Vis absorption bands in ethanol are assigned to the corresponding electronic transitions and the electronic absorption spectra of Schiff bases Ib and IIb are studied in organic solvents of different polarities. The UV/Vis absorption spectra of 2‐amino‐3‐hydroxypyridine Schiff bases IIa and IIb are investigated in buffer solutions of different pH values containing 5% (v/v) methanol, and the results are utilized for the determination of pKa and ΔG* of the ionization of the phenolic OH‐groups. The fluorescence spectra of IIa and IIb are studied in organic solvents of different polarities.

The obtained spectral results are confirmed by some molecular calculations using the atom super position and electron delocalization molecular orbital theory for the Schiff base IIb.
Temperature Effects on Structural and Functional Properties of Rat Lens Phe71 Mutant αA‐Crystallins
Authors: Yan Ker‐Ming , Huang Show‐Huey , Subhan D. , Huang Fu‐Yung
Published: May 2015

In order to explore whether hydrophobicity or charge at the 71th residue is important for chaperone‐like activity, wild type (wt) and two mutant αA‐crystallins, F71W and F71R, with an extra 11 residues including 6 histidines tagged at the N‐terminal were prepared. Chaperone‐like activity toward dithiotreitol (DTT) induced insulin aggregation showed the 11 extra residues had little effect. The activity for F71W was as active as the wild type, while F71R was much less active. For the wild type and F71W, the activity increased with the increase of molar quantity; surprisingly, for F71R it caused a drastic decline. ANS fluorescence measurements showed F71R had the highest surface hydrophobicity, suggesting positive charge at this site caused the conformational alteration leading to the increase of hydrophobicity and this hydrophobicity resulted in the formation of high molecular weight aggregates (> 2000 kDa) observed from the thermal stability study. The thermal stability study revealed F71W was the most thermally stable crystallin. Chaperone‐like activity studies at various temperatures suggested the monomer and oligomer, 650 kDa, were responsible for chaperone function and surface hydrophobicity was not the prerequisite for activity. Near‐UV CD studies showed β‐sheet was the major secondary structure for all three crystallins and F71R had a higher percentage of random coil.
Fast Analysis of Free Amino Acids in Tobacco by HPLC with Fluorescence Detection and Automated Derivatization
Authors: Zhu Xiao‐Lan , Zhu Qing‐Sheng , Gao Yun
Published: May 2015

A fast, simple, and sensitive HPLC method for the determination of free amino acids in tobacco was described. A fully automated sample processor performed precolumn derivatization of both primary and secondary amino acids with o‐phthalaldehyde/3‐mercaptopropionic acid and 9‐fluorenylmethyl chloroformate (FMOC‐Cl), respectively. All reactions were fully automated by means of an injector programme and accomplished in 10 min. Sample preparation consisted of a single step of extraction with 0.1 mol/L HCl at ambient temperature (assisted by sonication) in 30 min, followed by filtration of an aliquot and derivatization. By optimization of sample preparation and HPLC conditions, separation of 20 amino acids in 30 min was achieved. Detection limits ranged from 0.50 to 1.40 μg/g; coefficients of variation ranged from 1.8% to 3.9%; recoveries ranged from 84.6% to 108.5%. The method was applied to the analysis of amino acids contents of tobacco leaves in different varieties and flue‐curing period.
A Novel Ion‐Selective Electrode for Determination of the Mercury(II) Ion Based on Schiff Base as a Carrier
Authors: Zhang M. , Wu X. , Chai Y. Q. , Yuan R. , Ye G. R.
Published: May 2015

A new poly(vinyl chloride) (PVC) membrane ion‐selective electrode based on bis‐salicyladehyde‐diaminjodipropylamine (BSDDA) as an ion carrier was successfully applied to the detection of Hg2+ ions. This electrode displayed good selectivity toward Hg2+ in comparison with other metal ions and exhibited a Nernstian slope of 30.5 ± 0.4 mV per decade of Hg2+ over a concentration range of 9.5 × 10−7 to 6.4 × 10−2 M of Hg2+ in the pH range 1.5 to 3.5. The detection limit was 7.0 ± 0.2 × 10−7 M and response time was about 10 s to 25 s. The electrode can be used at least 2 months without apparent divergence in potential. In addition, the effects of experimental parameters such as membrane composition, nature and amounts of plasticizer and additive were investigated. The proposed electrode could be used as an indicator electrode in the detection of Hg2+ in samples.
Simultaneous Determination of Aluminum, Cadmium and Lead in Whole Blood by Simultaneous Atomic Absorption Spectrometry with Oxygen Charring
Authors: Tsay Tong‐Shung , Huang Yeou‐Lih , Tseng Wei‐Chang
Published: May 2015

A method for the simultaneous determination of aluminum (Al), cadmium (Cd) and lead (Pb) in whole blood has been developed by using simultaneous atomic absorption spectrometry (SIMAAS) with oxygen charring. The optimized conditions for the simultaneous determination of Al, Cd and Pb were obtained in the presence of palladium (Pd) as the chemical modifier, using 600 °C and 2400 °C as the pyrolysis and the atomization temperature, respectively. The whole blood samples were diluted 1+5 (v/v) directly with 0.1% (v/v) Triton X‐100. Oxygen was employed to eliminate the interference of carbonaceous residues in the charring step before pyrolysis. The calibration curves were carried out with aqueous standard solutions and the linear ranges were 0–40 ng mL−1, 0–4 ng mL−1 and 0–40 ng mL−1 for Al, Cd and Pb, respectively. The detection limits were 0.96 ng mL−1 (19.2 pg) for Al, 0.03 ng mL−1 (0.6 pg) for Cd and 0.60 ng mL−1 (12.0 pg) for Pb. The spiked recoveries of Al, Cd and Pb in whole blood were 98.0%, 100.0% and 101.7%, respectively. The accuracy of the proposed method was evaluated with the analysis of a whole blood certified reference material (Seronorm, level 2). The found concentrations were in agreement with the recommended values. The proposed method has been successfully applied to the simultaneous determination of Al, Cd and Pb in whole blood of healthy volunteers before and after eating barbecued foods.
QSAR Study of Anti‐HIV Activities against HIV‐1 and Some of Their Mutant Strains for a Group of HEPT Derivatives
Authors: Zarei Kobra , Atabati Morteza
Published: May 2015

A quantitative structure activity relationship analysis (QSAR) has been applied to a data set of 23 derivatives of 1–2‐[(hydroxyethoxy)methyl]‐6‐(phenylthio)thymine (HEPT) with their anti‐HIV activities. Semi‐empirical quantum chemical calculations at the AM1 level were used to find the 3D geometry of the studied molecules. Whole numbers of descriptors were calculated with Dragon software, and a subset of calculated descriptors was selected from 1481 Dragon descriptors with the forward stepwise multiple linear regression (MLR) method. Then anti‐HIV activities against HIV‐1 and four HIV‐1 mutant strains containing single mutations in their reverse transcriptases (RTs) were studied, and five equations with excellent statistical qualities were obtained using multiple linear regression. The activities of these compounds were also calculated in predictions, and good correlation coefficients were obtained.
Non‐Covalent Functionalization of Carbon Nanotubes with Surfactants and Polymers
Authors: Hu Chang‐Yuan , Xu Ya‐Juan , Duo Shu‐Wang , Zhang Rong‐Fa , Li Ming‐Sheng
Published: May 2015

Carbon nanotubes (CNTs) possessing unique structure and properties are attractive building blocks for novel materials and devices of important practical interest. However, the insolubility or poor dispersibility of pristine CNTs in common solvents poses a serious obstacle to their further development. To effectively utilize CNTs as building blocks for nanotechnology, CNTs have been covalently and noncovalently functionalized in a number of ways to render them soluble in aqueous or organic solutions. Here, we review recent progress and advances that have been made on dispersion of carbon nanotubes in aqueous and organic media by non‐covalent functionalization with surfactants and polymers.
Electrochemical Behavior of Apigenin at a Glassy Carbon Electrode and its Analytical Application
Authors: Xing Tian‐Lai , Wang Fei , Mao Yue‐Ying , Wang Li‐Ping , Ye Bao‐Xian
Published: May 2015

The electrochemical behavior of the antitumor herbal drug apigenin was studied in 0.1 mol L−1 B‐R buffer solutions (50% ethanol, pH 3.0) by cyclic voltammetry (CV) at a glassy carbon electrode. In CV, two oxidation peaks (P1 and P2) with Ep1 = 1.03V and Ep2 = 1.23 V appeared at a scan rate of 0.05 V s−1, and a new electroanalytical method for this herbal drug was established according to the oxidation peak P2. The peak currents have a linear relationship with apigenin concentration in a range from 9.0 × 10−7 to 2.0 × 10−5 mol L−1. Using the established method, apigenin in a herbal drug was determined without pre‐separation with satisfactory results. Moreover, the electrode dynamics parameters were also investigated by electrochemical techniques and the possible electrode reaction mechanism was deduced.
SnCl4/SiO2: An Efficient Heterogeneous Alternative for One‐Pot Synthesis of β‐Acetamidoketones
Authors: Mirjalili Bi Bi Fatemeh , Hashemi Mohammad M. , Sadeghi Bahareh , Emtiazi Hamideh
Published: May 2015

Enolizable ketones have been reacted in a one‐pot method with aromatic aldehydes, acetyl chloride and acetonitrile at room temperature in the presence of SnCl4/SiO2 to furnish the corresponding β‐acet‐amidoketones in improved yields. Acetylation of an aromatic hydroxyl group was observed while using 4‐hydroxybenzaldehyde or vanillin and the corresponding β‐acetamidoketones were isolated in an excellent yield.
Efficient Synthesis of 2‐Aminothiazoles and Fanetizole in Liquid PEG‐400 at Ambient Conditions
Authors: Lin Pei‐Ying , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching
Published: May 2015

A simple and practical procedure for the synthesis of 2‐aminothiazoles from α‐tosyloxyketones and thioureas is described using PEG‐400[poly(ethylene glycol‐400)] at ambient conditions. The developed protocol is successfully applied for the preparation of an anti‐inflammatory drug, Fanetizole.
Spectrofluorimetric and Spectrophotometric Determination of Oxamniquine in Pharmaceuticals and Biological Fluids via Derivatization with 4‐Chloro‐7‐Nitrobenzo‐2‐oxa‐1,3‐Diazole (NBD‐Cl)
Authors: El‐Enany N. , Ahmida N. , Belal F.
Published: May 2015

Spectrophotometric and spectrofluorimetric methods were developed for the determination of oxamniquine (OXM). Both methods are based on coupling with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl) in borate buffer of pH 7.6, and the reaction product was measured at 400 nm (Method I). The same product was measured by spectrofluorimetry at 480 nm upon excitation at 400 nm (Method II). The absorbance and the fluorescence intensity were enhanced by addition of sodium dodecyl sulphate (SDS). The absorbance‐concentration plot is rectilinear over the range of 5–25 μg/mL with an LOD of 0.31 μg/mL. The fluorescence‐concentration plot is linear over the range of 0.2–1.2 μg/mL with an LOD of 0.03 μg/mL. Both methods were applied to the analysis of capsules, and the results were in good agreement with those obtained using the official method. The method was applied to spiked human plasma; the mean % recovery (n = 5) is 101.05 ± 1.65. A proposal of the reaction pathway is presented.
Effects of Phenyl‐ and Methyl‐Substituents on p‐Phenylenediamine, an Electrochemical and Spectral Study
Authors: Chung Yi‐Chun , Su Yuhlong Oliver
Published: May 2015

Two 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

Furazolidone 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

Some 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

This 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

Although 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

1‐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

Novel 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

PEG‐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

The 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

A 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

A 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

α‐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

The 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

The 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

A 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

A 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

The 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

Manganese 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

In 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

Essential 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

The 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.
Finding a Facile Method to Synthesize Decahedral Silver Nanoparticles through a Systematic Study of Temperature Effect on Photomediated Silver Nanostructure Growth
Authors: Lee Yao‐Chang , Chen Sin‐Jia , Huang Cheng‐Liang
Published: May 2015

To the best of our knowledge, few reports have been concerned with the effect of temperature on photomediated silver nanostructure growth. In this work, the shape evolution from spherical silver nanoparticles to silver nanoprisms and nanostructures in other shapes under the irradiation of a sodium lamp (λmax = 589 nm, 0.66 W/cm2) at various temperatures (i.e., 15, 40, 60, and 80 °C) were studied by recording the TEM images and time‐course UV‐vis‐NIR spectra of the silver colloids. From TEM and spectra analysis, it was found that the photomediated silver nanoparticle shape conversion process would be faster at a higher temperature, i.e., ca. 2 hours at 80 °C, and slower at a lower temperature, i.e., ca. 17 hours at 15 °C. The silver nanoplates synthesized at a higher temperature had a narrower size distribution and were thicker than those synthesized at a lower temperature. Some decahedral silver nanoparticles, about 10% of the final irradiation products, were observed in the synthesis (with a sodium lamp) at 15 °C. In order to produce a higher yield of decahedral silver nanoparticles, the sodium lamp was replaced with blue LEDs (λmax = 450 nm), which have a wavelength closer to the SPR of decahedral silver NPs (ca. 490 nm). The decahedral silver nanoparticles with a fairly narrow size distribution were obtained by irradiating the spherical nanoparticle colloids with the blue LEDs at 2 °C in the absence of PVP or other large‐molecular‐mass surfactants.
Development and Validation of Ropinirole Hydrochloride and its Related Compounds by UPLC in API and Pharmaceutical Dosage Forms
Authors: Krishnaiah CH , Murthy M. Vishnu , Reddy A. Raghupathi , Kumar Ramesh , Mukkanti K.
Published: May 2015

A novel stability‐indicating gradient reverse phase ultra performance liquid chromatographic (RPUPLC) method was developed for the determination of purity of Ropinirole in presence of its impurities and forced degradation products. The method was developed using Waters Aquity BEH 100 mm, 2.1 mm, 1.7 μm C‐8 column with mobile phase containing a gradient mixture of solvent A and B. The eluted compounds were monitored at 250 nm. The run time was within 4.5 min which Ropinirole and its four impurities were well separated. Ropinirole was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Ropinirole was found to degrade significantly in oxidative and base stress conditions and stable in acid, water, hydrolytic and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities, thus proved the stability indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of Ropinirole in pharmaceutical dosage forms and dissolution studies.
A Comparative Investigation on Efficacy of Two Methodologies of Solid Phase Extraction for Separation and Pre‐Concentration of Trace Copper in Aqueous Samples Prior to Flame Atomic Absorption Spectrometric Determination
Authors: Noei‐Aghaei Mohammad Amin , Mohammadhosseini Majid , Zamani Hassan Ali , Nekoei Mehdi
Published: May 2015

This report describes the capability of two facile, sensitive and concentrative methods for quantification of sub‐ppm levels of copper in different solutions using octadecyl silica bonded phase membrane (OSPM) disks. The first standpoint is based on introduction a homogenized miscellaneous solution of copper‐1‐(2‐pyridylazo)‐2‐naphtol (PAN) to the surface of an OSPM disk. The second perspective is the usual manner and is performed by impregnation or modification of the sorbent surface. All the affecting experimental variables such as pH, amount of modifier, eluent type, concentration of each metal and ligand, surfactant type, sample and eluent flow‐rate, time and disk capacity are also tested. The results reveal that the first way is considerably more time consuming. However, the second method possesses high break‐through volume (2000 mL) and lower detection limit (0.01 ng mL−1). Both the methods have been successfully applied for isolation and determination of trace copper in different aqueous and real samples.
Bio‐Orthogonal Protein Labeling Methods for Single Molecule FRET
Authors: Chang Wei‐Hau , Liu Yuhua
Published: May 2015

Single‐molecule fluorescence resonance energy transfer (smFRET) has emerged as a powerful technique for visualizing the dynamics and architecture of proteins, multi‐subunit protein complexes, or protein‐nucleic acid complexes. To suffice a FRET study, selective labeling with a pair of a donor dye and an acceptor dye is required, with the two dyes on two sites on a protein, or with the donor on one protein sub‐unit while the acceptor on another subunit, or with the pair divided between protein and DNA (RNA). Due to the availability of orthogonal chemical moieties, most biophysicists armed with single FRET have been limited to the processes of nucleic acids metabolism by studying protein‐DNA (‐RNA) interactions. Nevertheless, diverse biological processes usually involve communications between proteins. Indeed, protein‐protein interactions constitute fundamental questions regarding intra‐ and intercellular signal transduction and are under intensive research, yet mainly by conventional methodologies. In this review, various bio‐orthogonal methods recently developed for labeling proteins via protein domains, small peptides, or single amino acids are examined. These approaches comprise a repertoire that overcomes the challenges of labeling two sites on a protein or a protein complex to facilitate the investigation of protein‐protein interactions by the modern single molecule FRET method.
Efficient Energy and Electron Transfer between Donor and Acceptor Chromophores in Aluminophosphate Hybrid Materials
Authors: Lo Chih‐Yuan , Chen Chih‐Hsien , Tsai Tim W. T. , Zhang Long , Lim Tsong‐Shin , Fann Wunshain , Chan Jerry C. C. , Luh Tien‐Yau
Published: May 2015

The first organic‐inorganic hybrid materials (OIHMs) having one or a combination of two chromophores in different ratios are obtained from the aryl phosphonic acid and aluminum lactate via sol gel process. The structures of these OIHMs are analyzed by the 27Al and 31P NMR. The fluorescence resonance energy transfer (FRET) as well as photoinduced electron transfer (PET) between donor and acceptor chromophores in these hybrid materials have been investigated and the efficiencies can be up to 97 and 93%, respectively.
Molecular Switching in Nanospaces
Authors: Dube Henry , Durola Fabien , Ajami Dariush , Rebek Julius
Published: May 2015

Switching devices that operate on the molecular level lie at the heart of nanomachinery. The energies involved range from scores of kcal/mol during cleavage or formation of covalent bonds to a few kcal/mol when the signals are changes in conformation. Here we examine three systems that use light, metal/ligand binding, and acid/base chemistry as switching devices to transfer molecules in and out of the confined environments of encapsulation complexes or cavitands. The events are reversible and the original states can be recovered by treatment with brief heating, conventional chelating agents, or changes in protonation states, respectively. The control over these spaces augurs well for applications in drug delivery and sensors for small molecules.
Supramolecular Structure of an Unsymmetrical Pyrazine‐Modulated Tetrapyridyltriamide and Its Complexes
Authors: Wang Wen‐Zhen , Ismayilov Rayyat Huseyn , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

An unsymmetrical pyrazine‐modulated oligo‐α‐pyridylamine ligand as N2‐(pyrazin‐2‐yl)‐N6‐(6‐(pyridin‐2‐ylamino)pyridin‐2‐yl)pyridine‐2,6‐diamine (H3tpz) and its copper(II) and cobalt(II) complexes have been synthesized and structurally characterized. The free ligand H3tpz (1) exhibits a syn‐anti‐syn‐anti‐syn‐anti conformation, and shows a double chain supramolecular structure through hydrogen bonds and π‐π interactions. H3tpz is a quadridentate ligand in both copper and cobalt mononuclear complexes and coordinates to metal atoms in an all‐anti mode. The copper(II) ion in [Cu(H3tpz)(ClO4)]‐ClO4 (2) is five‐coordinated in tetragonal pyramid geometry with one of the perchlorate anions being weakly coordinated at the apex position. The cobalt(II) ion in [Co(H3tpz)(CH3OH)2](ClO4)2 (3) is six‐co‐ordinated in octahedron geometry. Extensive hydrogen bonds are formed, and construct the complexes 2 and 3 into 1D supramolecular structure.
Advances in Use of p‐H2 as a Novel Host for Matrix IR Spectroscopy
Authors: Bahou Mohammed , Huang Chiung‐Wei , Huang Ya‐Ling , Glatthaar Joerg , Lee Yuan‐Pern
Published: May 2015

A review of recent advances in IR spectroscopy using p‐H2 as a matrix host in our laboratory is presented. The softness of this novel p‐H2 matrix host not only makes high‐resolution spectroscopy feasible but also provides new applications. Molecular motion, such as the rotation of C2H4, internal rotation (torsion) of CH3OH, and rotation of CH3F about a single axis are characterized in this p‐H2 matrix. In contrast, no evidence for rotation of CH3I and CH3 was found. The diminution of the cage effect leads to the possibility of production of free radicals via either photolysis in situ or bimolecular reactions of molecules with atoms that are produced in situ from their molecular precursors. Taking advantage of these unique features, we identified the IR spectrum of CH3 produced from photolysis of CH3I and CH3S produced from photolysis of CH3SCH3 and CH3SSCH3. The reaction of Cl with CS2 in solid p‐H2 yields ClSCS instead of ClCS2. The reaction of Cl with HCOOH in solid p‐H2 yields only a complex, Cl·HCOOH, not HCl and HOCO. The presence of o‐H2 in trace proportions turned out to be an important factor in the interpretation of IR spectra of species embedded in solid p‐H2. Experimental techniques to minimize the amount of o‐H2 and to characterize its relative concentration with spectra of H2O·o‐H2 are discussed.
Preparation and Characterization of Ni or Co/Cu Multilayer Nanowires
Authors: Liu Ru‐Shi , Chang Sung‐Chun , Chen Po Yuan , Hu Shu‐Fen , Huang Chao Yuan
Published: May 2015

Highly ordered nanowires with multilayer structure of Ni/Cu, have been successfully prepared by pulsed chemical electrodeposition into nanoporous templates and the diameter (35 and 200 nm) of wires can be easily controlled by pore size of template. The nanowires have been characterized by transmission electron microscopy (TEM), magnetic force microscopy (MFM), and vibrating sample magnetometer (VSM) and high magnetic perpendicular anisotropy can be achieved by modulating the shape of nanowires. It was found that the coercivity (Hc) and squarness (S: Mr/Ms) of the nanowires are strongly dependent on the diameter and aspect ratio as well as on dipolar coupling between the ferromagnetic segments and the nanowires (aspect ratio: 11.4) can be obtained high perpendicular magnetic anisotropy with Hc: 895 Oe and S: 0.77 of Ni/Cu nanowires. The magnetoresistance ratios along the parallel and perpendicular axes of nanowires are 23.4% and 7.2% respectively. Owing to its high bit density, the structure may be suitable for ultrahigh‐density magnetic recording media.
Carbonylchromium Chalcogenide Complexes: Synthesis, Reactivity and Properties
Authors: Shieh Ming‐Huey , Miu Chia‐Yeh
Published: May 2015

Recently, we have developed several synthetic routes to a series of chalcogen‐containing group 6 (emphasizing on chromium) carbonyl clusters, in which the interesting structural transformations, reactivity, and properties of the resultant clusters have also been investigated. This review will focus on the aspects of the research carried out in our laboratory. In this account, the practical synthetic methodologies and metal‐metal exchange and cluster expansion reactions together with structural features of these Cr‐containing complexes are systematically described and compared.