bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Liquid‐Solid Flotation Separation of Cadmium by Ammonium Sulfate‐Potassium Iodide‐Cetylpyridine Chloride‐Water System
Authors: Tu Chang‐Qing , Wen Xin‐Rong 
Published: May 2015

AbstractThe liquid‐solid flotation separation behaviors of Cd2+ in ammonium sulfate‐potassium iodide‐cetylpyridine chloride‐water system and the conditions for the separation of Cd2+ from other metal ions were studied. The results showed that in the presence of 1.0 g (NH4)2SO4 and when the dosage of 0.1 M potassium iodide was 2.0 mL and 0.01 M cetylpyridine chloride (CPC) solution was 1.0 mL respectively, the formed water‐insoluble ternary association complex of KI‐CPC‐Cd floated above water phase and liquid‐solid phases were formed with clear interface. In this condition, Zn2+, Mn2+, Fe2+, Co2+, Ni2+ and Al3+ could not be floated and Cd2+ was floated quantitatively at pH 5.0. Therefore, the quantitative separation of Cd2+ from the above metal ions could be achieved. The quantitative flotation separation determination of Cd2+ in the sample of synthetic water and industrial waster water was performed, and the results agreed well with those by AAS method. The recoveries were 97.2%∼102.4%, and the RSD was 1.8%.
Trace Determination of Benzalkonium Chlorides in River and Wastewater by Capillary Electrophoresis following Solid‐Phase Extraction Coupled with Salting‐Out Extraction
Authors: Liu Hsueh‐Ying , Ding Wang‐Hsien 
Published: May 2015

AbstractTrace levels analysisbenzalkonium chlorides (BAKs) in river water and wastewater treatment plants (WWTP) effluents were determined by capillary electrophoresis (CE) following solid‐phase extraction (SPE) and salting‐out extraction. Salting‐out extraction using an appropriate ratio of sodium chloride (NaCl) and acetonitrile (ACN) mixed with concentrated SPE elutant was capable of providing more than 500‐fold enhancement in detection sensitivity. The ratios of ACN and NaCl for salting‐out extraction were investigated and optimized. Matrix interference was eliminated by salting‐out extraction. Limits of quantitation of BAK homologues were achieved at 0.1 μg/L in 250 mL water samples. Recoveries of BAKs in various spiked water samples ranged from 70% to 84% with relative standard deviation (RSD) less than 9%. Trace amounts of total BAKs were detected in river water and WWTP effluent samples ranging from 27 to 145 μg/L at the first time by CE.
Preparation and Photocatalytic Activity of TiO2 Films on Silica Glass Substrates by Assembly Technique
Authors: Chen Ru‐Fen , Zhang Cui‐Xuan 
Published: May 2015

AbstractNanostructured TiO2 coating films on silica glass substrates were prepared by the assembly technique. TiO2 colloids were synthesized employing the sol‐gel method using TiCl4 as a precursor. The effect on the surface structures which was caused by the polyethylene glycol (PEG) added to the precursor solution and the photocatalytic activity were studied. The experimental results showed that the cobble‐like TiO2 coating films were synthesized at 500 °C. On the surface of the samples, TiO2 films exhibited uniform shape and a narrow size distribution. The result of proper PEG added to the precursor solution led to the decreasing of the size of TiO2 particles and the increasing of the surface area of the samples. The photocatalytic activity of TiO2 films with PEG was higher than that of samples without PEG.
Membrane Transport of Pb(II) with a Cooperative Carrier Composed of Dibenzyldiaza‐18‐Crown‐6 and Palmitic Acid
Authors: Kazemi Sayed Yahya 
Published: May 2015

AbstractA chloroform membrane system containing a given mixture of dibenzyldiaza‐18‐crown‐6 and palmetic acid was applied for transport of Pb2+ ions. The transport was capable of moving metal ions “uphill”. Thus, it was possible to follow the transfer of Pb(II) from the aqueous source phase to the organic layer and from the organic layer to the receiving phase. The effects of thiosulfate concentration in the receiving phase, palmetic acid and dibenzyldiaza‐18‐crown‐6 concentration in the organic phase on the efficiency of the transport system were examined. By using S2O32− ion as metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is 96 ± 1.5%. The selectivity and efficiency of lead transport from aqueous solution containing Cu2+, Tl+, Ag+, Co2+, Ni2+, Mg2+, Zn2+, Hg2+, Cd2+, Ca2+ were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of Ag+ and Cu2+ were diminished drastically.
Extractive Spectrophotometric Methods for Determination of Clarithromycin in Pharmaceutical Formulations Using Bromothymol Blue and Cresol Red
Authors: Shah Jasmin , Jan M. Rasul , Manzoor Suraya 
Published: May 2015

AbstractTwo simple and sensitive extractive spectrophotometric methods have been described for the analysis of clarithromycin in pure form and in pharmaceutical formulations. The methods involved formation of yellow colored chloroform extractable ion‐association complexes of clarithromycin with bromothymol blue (BTB) and cresol red (CR) in buffered aqueous solution at pH 4. The extracted complexes showed maximum absorbance at 410 and 415 nm for BTB and CR, respectively. Beer's law is obeyed in the concentration ranges 0.1–20 μg mL−1 and 2.0–20 μg mL−1 of clarithromycin with molar absorptivity of 2.01 × 104 and 4.378 × 103 for BTB and CR, respectively. The composition ratio of the ion‐association complex was clarithromycin: BTB and CR = 1:1 as established by Job's method. The methods have been applied to the determination of drug in commercial formulations. The results of analysis were validated statistically and through recovery studies.
New Approaches for the Synthesis of Thiazoles and Their Fused Derivatives with Antimicrobial Activities
Authors: Wardkhan Wagnat W. , Youssef Mohamed A. , Hamed Faten I. , Ouf Salama A. 
Published: May 2015

AbstractThe 2‐ethoxy carbonyl methylene thiazol‐4‐one (3) reacts with acetophenone (4) to give the ethyl 2‐(4‐oxo‐4,5‐dihydro‐thiazol‐2‐yl)‐3‐phenyl‐2‐butenoate (5). The reactivity of the latter product towards aromatic aldehydes 6a‐d, cyanomethylene reagents 9a,b, aromatic aldehydes 13a‐d, phenylisothiocyanate (16), elemental sulfur and aromatic amines (20a‐c) was studied to give arylidene, pyridine, thiophene and anilide derivatives. Some of the newly synthesized derivatives were used to synthesize fused derivatives. The antimicrobial activities of the newly synthesized products were tested in vitro for antimicrobial activity against two bacterial isolates, one saprophytic (Escherichia coli) and the other parasitic (Xanthomonas citri) and for antifungal activity against one saprophytic (Aspergillus fumigatus) and two phytopathogenics (Rhizoctonia solani and Fusarium oxysporum).
A Novel Method for the Synthesis of 4(3H)‐Quinazolinones
Authors: Jing Xiao‐Bi , Li Zhen , Pan Xin , Shi Yao‐Cheng 
Published: May 2015

AbstractDifferent metal perchlorates were screened to catalyze the three‐component reaction of anthranilic acid, triethyl orthoformate and amines to afford quinazolin‐4(3H)‐ones in solvent‐free conditions. Ni(ClO4)2 or Zn(ClO4)2 was demonstrated to be efficient to catalyze the reaction.
Convenient, Easy and Highly Regioselective Preparation of Haloalcohols from the Reaction of Epoxides with Elemental Halogen Catalyzed by Hexamethylenetetramine (HMTA)
Authors: Naeimi Hossein 
Published: May 2015

AbstractThe highly regioselective cleavage of epoxides into corresponding vicinal haloalcohols with elemental halogen has been catalyzed by hexamethylenetetramine (HMTA). This method occurred under neutral and mild conditions with high yields and short reaction times in various aprotic solvents even when sensitive functional groups were present.
Effect of Indole‐3‐Acetic Acid Analogs on the Differentiation of HL‐60 Cells
Authors: Lien Jin‐Cherng , Jiang Yu‐Dong , Chen Chun‐Jen , Kuo Sheng‐Chu , Huang Li‐Jiau 
Published: May 2015

AbstractIn continuing search for novel cell differentiation agents, a series of derivatives of indole‐3‐acetic acid and indole‐3‐carboxylic acid were prepared and tested against HL‐60 cells for their differentiation and antiproliferation activities. Among them, N‐ethyl‐1‐benzylindole‐3‐carboxamide (14) was the most potent, whereas N‐methyl 1‐benzylindole‐3‐acetamide (5) and N‐methyl 1‐benzylindole‐3‐carboxamide (13) synergistically potentiated with all‐trans‐retinoic acid to induce cell differentiation as well as antiproliferation. Our results indicate that these compounds are effective cell differentiation and antiproliferation agents in combination with retinoic acid.
A New Set of Amino Acid Descriptors for the Development of Quantitative Sequence‐Activity Modelings of HLA‐A*0201 Restrictive CTL Epitopes
Authors: Liang Gui‐Zhao , Shu Mao , Li Sheng‐Shi Zl. 
Published: May 2015

AbstractA new set of amino acid descriptors, SZOTT (Scores of Zero dimension, One dimension, Two dimension, Three dimension) was derived from principal component analysis on a matrix of 1369 descriptors including 0D, 1D, 2D and 3D information of 20 coded amino acids. SZOTT scales were then employed to represent structures of HLA‐A*0201 restrictive CTL epitopes, and further, quantitative sequence‐activity modelings (QSAMs) were constructed based on partial least squares and back‐propagation artificial neural networks. Satisfying results show that structural information related to biological activities of HLA‐A*0201 restrictive CTL epitopes can be preferably represented by SZOTT scales, which may be a useful structural representation technique for study of QSAMs of peptides.
The One‐Pot Synthesis of 2,4,5‐Triaryl‐Imidazoles Using Heteropolyacids as Heterogeneous and Recyclable Catalysts
Authors: Heravi Majid M. , Sadjadi Samaheh , Oskooie Hossein A. , Hekmatshoar Rahim , Bamoharram Fatemeh F. 
Published: May 2015

Abstract2,4,5‐triaryl imidazoles were obtained in high yields with excellent purity from the condensation of benzaldehydes, NH4OAc and 1,2‐diketone in the presence of a catalytic amount of various heteropolyacids (HPAs).
Hypervalent Iodine(III) Sulfonate Mediated Synthesis of α‐Thiocynanatoketones in a Task‐Specific Ionic Liquid [bmim]SCN
Authors: Huang Hsin‐Yu , Wang Huey‐Min , Hou Rei‐Sheu , Cheng Hui‐Ting , Chen Ling‐Ching 
Published: May 2015

AbstractThe task‐specific ionic liquid (TSIL) and 1‐n‐butyl‐3‐methylimidazolium thiocynanate, ([bmim]SCN) were used as the medium as well as the reactant for the synthesis of α‐thiocynanatoketones by the reaction with α‐sulfonyloxy aryl ketones. Significant rate enhancements and improved yields have been observed.
Trimethylsilylation of Hydroxyl Group with 1,1,1,3,3,3‐Hexamethyldisilazane (HMDS) Catalyzed by Tribromomelamine (TBM)
Authors: Ghorbani‐Choghamarani Arash , Zolfigol Mohammad Ali , Hajjami Maryam , Jafari Shila 
Published: May 2015

AbstractTribromomelamine (TBM) can be used as a novel catalyst for the trimethylsilylation of alcohols and phenols with 1,1,1,3,3,3‐hexamethyldisilazane (HMDS). A wide variety of hydroxyl groups were selectively protected in CH2Cl2/CH3CN under mild conditions.
Plasmonic Properties and Size Programming: A Quantitative Study for Photosynthesized Gold Nanoparticles
Authors: Ou Chun‐Chang , Yeh Hui‐Wen , Chang Fang‐Yi , Yang Chung‐Sung 
Published: May 2015

AbstractA novel two‐component peak quantitative spectra deconvolution model is employed to elucidate the relationship between the plasmonic properties and the concentration‐dependent Au nanocrystals nucleation. The reactions with the initial concentration of starting reagent NaAuCl4 from 0.75 mM to 0.1 mM are monitored. The peak area variation between component peak (b), large size nanoparticles (d ≥ 8.1 nm), and component peak (a), small size nanoparticles (d ≤ 8.0 nm), demonstrates that the initial concentration of NaAuCl4 plays a decisive factor to determine the (b/a) ratio, i.e. the growth progresses of Au nanoparticles. If the initial concentration of NaAuCl4 is higher than 0.2 mM, two independent growth progresses of Au nanoparticles are observed, and a continuous λmax blue‐shift of surface plasmon absorption peak accompanied with the second growth progress is measured. On the other hand, in the reactions with the initial concentration of NaAuCl4 lower than 0.2 mM, only one crystal growth progress of Au nanoparticles is shown, and the blue‐shift phenomenon of absorption peak induced by the second crystal growth progress no longer exists.
Synthesis of Nano‐Sized Zinc Oxide Photocatalyst by Combustion Method
Authors: Lin Cheng‐Shiung , Hwang Chyi‐Ching 
Published: May 2015

AbstractThe objective of this research was to use combustion synthesis to create a nano‐sized ZnO photocatalyst using citric acid as the fuel and zinc nitrate as the oxidant. The starting materials were mixed in a stoichiometric ratio, and a slurry precursor with high homogeneity was formed. The precursor was ignited at room temperature, resulting in dry, loose, and voluminous ZnO powders. The powders, characterized by SEM, TEM and XRD, showed a particle size range of 40 to 80 nm with a wurtzite structure. The ZnO powders were introduced as a photocatalyst for the degradation of methyl orange, which was adopted as a model compound. UV light (6W) was used as the irradiation source to induce synthesized ZnO powders to perform catalytic activity. The photocatalytic reaction was executed in 40 mL of a 10 ppm methyl orange aqueous solution under 254 nm UV illumination. In this work, it was observed that both UV light and ZnO powders are needed for the photocatalytic reaction. In addition, it was found that increasing the amount of ZnO powder present in the MO (methyl orange‐C14H14N3NaO3S) solution did not correlate directly with an increase in photocatalytic ability. It was found that the scattering problem of UV light also needs to be considered. The optimized photocatalytic degradation ratio in this work reached 92.7%.
Theoretical Study of Heterocyclic Nitro Compounds for Use as Novel Explosives and Propellants
Authors: Ju Xue‐Hai , Wang Zun‐Yao , Qiu Ling 
Published: May 2015

AbstractThe heats of formation (HOFs) of heterocyclic nitro compounds were obtained by using a density functional theory B3LYP method with 6‐31G* and 6‐311+G** basis sets. The isodesmic reactions designed for the evaluation of HOFs keep most of the basic ring structures of the title compounds and thus ensure the credibility of the results. The values of HOFs are 567.90, 874.29 and 975.83 kJ/mol at the B3LYP/6‐31G* level for hexanitrohexazaadamantane (A), nonanitrononaza‐tetracyclo[7.3.1.13,7.15,11] pentadecane (B) and tetranitrotetrazacubane (C) respectively. The predicted detonation velocities of the title compounds are larger than, and detonation pressures are much larger than that of the widely used 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX). The dissociation energy for the weakest C‐N bonds in the cage skeleton of the title compounds are 137‐144 kJ/mol at the B3LYP/6‐31G* level.
Synthesis and Fluorescent Properties of 2‐Arylamino‐5‐(3‐Aryl‐1‐Phenyl‐Pyrazol‐4‐Yl)‐1,3,4‐Thiadiazoles
Authors: Li Cun‐Kui , Cao Ling‐Hua 
Published: May 2015

AbstractA series of novel pyrazolyl‐substituted 1,3,4‐thiadiazole derivatives (6a‐6d, 7a‐7d, 8a‐8d) were prepared by cyclization of the intermediate 3‐aryl‐l‐phenyl‐pyrazol‐4‐ylformaldehyde 4′‐phenylthiosemicarbazones with 0.5 M ferric chloride solution. The structures of the new compounds were confirmed by IR, 1H NMR and elemental analysis. Simultaneously, the compounds were detected by fluorescence spectrophotometer and had preferable fluorescence activity.
Synthesis of 3‐Aryl‐2,5‐Dihydro‐1‐Benzoxepines from Phenol via Ring‐Closing Metathesis
Authors: Tsai Jui‐Chi , Li Sie‐Rong , Chen Liang‐Yeu , Chen Po‐Yuan , Joung Jia‐Ying , Shu Chung‐Jung , Lo Yu‐Fuan , Lin Chun‐Nan , Wang Eng‐Chi 
Published: May 2015

AbstractIn this paper, the synthesis of 3‐aryl‐2,5‐dihydro‐1‐benzoxepines is described. While the reaction was started from phenol and based on the sequential reactions such as Claisen rearrangement, O‐alkylation, Wittig reaction, and ring‐closing metathesis (RCM), a series of new 3‐aryl‐1‐benzoxepines were prepared in good overall yields.
Speciation Analysis of Dissolved Copper in Wastewater with Azocarmine B by Light‐Absorption Ratio Variation Combined with Continuous Flow Analysis
Authors: Wang Hong‐Yan 
Published: May 2015

AbstractThe sensitive complication between Cu(II) and of azocarmine B (ACB) at pH 6.03 was characterized by the spectral correction method and the complex Cu(ACB)2 was formed. Because of a good selectivity, this reaction was used for the determination of Cu(II) by the light‐absorption ratio variation approach combined with the continuous flow analysis (CFA). The limit of detection of Cu(II) is 0.04 mg/L, the recovery is between 97 and 100% and about 30 samples could be analyzed per hour by CFA. By means of the recommended method, the organic species and inorganic ion species of Cu(II) in two wastewater samples were determined respectively and the former occupies less than 20% of total dissolved Cu(II).
Assay of Phenformin Hydrochloride in Pharmaceutics by Coupling with Sodium Nitroprusside
Authors: Wang Min , Zhang Yan , Li Quan‐Min 
Published: May 2015

AbstractA novel and simple spectrophotometric method for the determination of phenformin hydrochloride using sodium nitroprusside as chromogenic reagent is developed in this paper. The experiment indicates that the sodium nitroprusside can react with the phenformin hydrochloride in a basic solution to form a product with colored N‐nitrosamines. The stoichiometric ratio of phenformin hydrochloride and sodium nitroprusside is 1:3 in the product. The maximal absorption wavelength (λmax) of the product is 520 nm, ϵ520 = 2.2 × 103 Lmol−1cm−1. A Good linear relationship is obtained between the absorbance (A) and the concentration (C) of phenformin hydrochloride in a wide range of 0.20‐400 μg mL−1. The equation of the linear regression is A = 0.03461 + 0.00907C (μg mL−1) with a linear correlation coefficient of 0.9991. The detection limit is 0.13 μg mL−1, and the relative standard deviation (R.S.D.) is 0.19%. The method is successfully applied to the determination of phenformin hydrochloride in tablet forms, and satisfactory recoveries are obtained.
Quantitative Analysis of Nicorandil in Commercial Tablets by Spectrophotometry
Authors: Rahman Nafisur , Ahmad Yasmin , Azmi Syed Najmul Hejaz , Sulaiman Saba A. J. 
Published: May 2015

AbstractThe main aim of this work is to develop and validate a spectrophotometric method for the determination of nicorandil in commercial tablets. The method is based on the reduction of the nitroxy ethyl group of nicorandil into carbonyl compound and nitrite ion by NH4Cl and Zn dust. The nitrite ion thus formed reacts with potassium iodide and starch in dilute HCl medium to form a blue product, which absorbs maximally at 550 nm. Beer's law is obeyed in the concentration range 0.4‐4.0 μg mL−1 with molar absorptivity of 7.92 × 104L mol−1 cm−1. The detection limit is 0.017 μg mL−1. The reaction conditions are optimized and validated as per the International Conference on Harmonisation guidelines (USA). The proposed method has been applied successfully for the determination of nicorandil in commercial tablets. The results of analyses are compared statistically with those of the author's spectrophotometric method, which confirmed that there is no significant difference between the methods compared.
Separation and Retention Behavior of Aromatic Carboxylic Acid Isomers by High‐Performance‐Liquid‐Chromatography Using β‐Cyclodextrin Bonded Phase with Diamine‐s‐Triazine Moiety
Authors: Lin Chen‐Hsing , Chen Chih‐Yu , Chang Shu‐Wen , Wu Jong‐Chang , Liu Yu‐Chih , Lin Ching‐Erh 
Published: May 2015

AbstractA β‐cyclodextrin (β‐CD) bonded phase with diamine‐s‐triazine moiety was prepared. The separation and retention behavior of the isomers of five aromatic carboxylic acids, including toluic acid, aminobenzoic acid, nitrobenzoic acid, hydroxybenzoic acid, and naphthoic acid were investigated by a high‐performance liquid chromatography (HPLC) using the β‐CD bonded phase prepared. The influence of mobile phase pH in the range of 2.7‐3.6 on the retention of these analytes was examined. The isomers of the aromatic carboxylic acids, with the exception of nitrobenzoic acid, were optimally and effectively separated at pH 2.7, while the three isomers of nitrobenzoic acid could be well separated at pH 3.3. Compared with the chromatographic results obtained previously on the amine‐s‐triazine‐β‐CD bonded phase, the retention factors of the isomers of aromatic carboxylic acid on the diamine‐s‐triazine‐β‐CD bonded phase increase to a relatively much greater extent. Thus, the functionality of the spacer arm of the bonded phase playing an important role in the retention of aromatic carboxylic acid isomers is demonstrated. The results also imply that the hydrogen‐bonding interaction and the mechanism of anion exchange sorption as well may contribute significantly to the retention mechanisms.
Coordination Behavior of a D‐Penicillaminato Aurate(I) Metalloligand Toward Coblat(III) Centers
Authors: Konno Takumi , Toyota Atsushi , Igashira‐Kamiyama Asako 
Published: May 2015

AbstractTreatment of (NH4)[Au(D‐Hpen‐S)2](D‐H2pen = D‐penicillamine) with CoCl2·6H2O in an acetate buffer solution, followed by air oxidation, gave neutral AuICoIII and anionic AuI3CoIII2 polynuclear complexes, [Au3Co3(D‐pen‐N,O,S)6]([1]) and [Au3Co2(D‐pen‐N,S)6]3− ([2]3−), which were separated by anion‐exchange column chromatography. Complexes [1] and [2]3− each formed a single isomer, and their structures were determined by single‐crystal X‐ray crystallography. In [1], each of three [Au(D‐pen‐S)2]3−metalloligands coordinates to two CoIII ions in a bis‐tridentate‐N,O,S mode to form a cyclic AuI3CoIII3 hexanuclear structure, in which three [Co(D‐pen‐N,O,S)2]− octahedral units and six bridging S atoms adopt trans(O) geometrical and R chiral configurations, respectively. In [2]3−, each of three [Au(D‐pen‐S)2]3− metalloligands coordinates to two CoIII ions in a bis‐bidentate‐N,S mode to form a AuI3CoIII2 pentanuclear structure, in which two [Co(D‐pen‐N,S)3]3− units and six bridging S atoms adopt ∧ and R chiral configurations, respectively.
Aromatization of Hantzsch 1,4‐Dihydropyridines in Solventless System Using Glycinium Chlorochromate
Authors: Hekmatshoar Rahim , Rezaei Akram , Haghighi Masoumeh , Ojghaz Azadeh Jafari , Sajadi Sodeh 
Published: May 2015

AbstractGlycinium chlorochromate (GCC) supported onto silica gel was used as an effective oxidizing agent for the aromatization of 1,4‐dihydropyridines to corresponding pyridine.
Determination of Cu, Fe, Pb and Zn by Flame‐AAS after Preconcentration Using Sodium Dodecyl Sulfate Coated Alumina Modified with Complexing Agent
Authors: Ghaedi Mehrorang , Niknam Khodabakhsh , Shokrollahi Ardeshir , Niknam Ebrahim 
Published: May 2015

AbstractA sensitive and simple method for the simultaneous preconcentration of trace transition and heavy metal ions is reported. The method is based on the adsorption of Cu, Fe, Pb and Zn on N,N′‐Diacetyl‐4‐bromo‐2,6‐di(aminomethyl)anisole (DABDAMA) loaded on sodium dodecyl sulfate (SDS) coated alumina. The metal content on the complexes are eluted using 6 mL of 2 mol l−1 nitric acid. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a low RSD. The method has been successfully applied for these metals content evaluation in samples including soil, blood and vegetable samples.