bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of pH and Concentration on Cs Ions Sorption and Diffusion in Crushed Granite by Using Batch and Modified Capillary Method
Authors: Wang Tsing‐Hai , Li Ming‐Hsu , Wei Yuan‐Yaw , Teng Shi‐Ping
Published: May 2015

A comprehensive evaluation of Cs ions sorption to and diffusion in crushed granite was conducted in this study. The sorption capacity of crushed granite suggested by the Langmuir model was 5.48 × 10−6 mol‐Cs/g‐granite. The distribution coefficient (Kd) was around 7.5 mL/g and pH independent. By using an in‐diffusion method with a modified capillary column, some diffusion relevant parameters of Cs ions in crushed granite were derived. The apparent diffusion coefficient (Da) seemed unaffected by Cs concentration (1.15 × 10−10 to 2.82 × 10−10 m2/s, at 10−7 and 10−3 M, respectively). The determined effective diffusion coefficients (De) were located in the window from 8.59 × 10−10 (10−7 M) to 1.69 × 10−9 (10−3 M) m2/s. Under various pH environments, pH independent Da (9.0 × 10−9 m2/s) and De (1.0 × 10−9 m2/s) values were observed. Under current systems, consistently higher De than Da implied the diffusion of Cs ions was governed by surface diffusion phenomenon. Whereas the pH insensitive feature indicated the Cs sorption to crushed granite was mainly through ion‐exchange reaction. Moreover, further SEM/EDS mapping clearly showed the adsorbed Cs ions were highly concentrated on the fracture surface of biotite.
Spectrofluorimetric Determination of the Hypertensive Drug Captopril Based on Its Oxidation with Cerium(IV)
Authors: El‐Didamony Akram Mohamed
Published: May 2015

A highly sensitive and specific spectrofluorimetric method for the analysis of captopril (CAP) in the pure form and in the tablet dosage forms has been described. The method was based on the oxidation of captopril by cerium(IV) in the presence of sulphuric acid and subsequent monitoring the fluorescence of the induced Ce(III) ion produced at λex= 256 nm and λem= 354 nm. All variables affecting the reaction conditions such as cerium(IV) concentration, type and concentration of acid medium, reaction time, diluting solvents, temperature and heating time were carefully studied and optimized. Under the experimental conditions used, an excellent linear relationship was obtained between fluorescence intensity and the concentration of CAP. A linear range of determination was verified for captopril concentrations between 0.1–1.3 μg mL−1and the correlation coefficient of determination was 0.9997. Quantitation and detection limits were calculated. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 1.14%. No interference could be observed from the excipients and additives are commonly presented in dosage forms. The proposed method was applied successfully for the assay of the studied drug in pure form and in pharmaceutical dosage forms. Recovery experiments revealed recovery of 99.82–100.21%. The results of the analysis show a good agreement with those obtained by official method stated in the United State Pharmacopoeia.
Flotation‐Spectrophotometric Determination of Trace Amounts of Thorium
Authors: Pourreza N. , Parham H. , Mirzavand P.
Published: May 2015

A simple, sensitive and reproducible flotation‐spectrophotometric method for the determination of thorium is reported. The method is based on the ion‐associate formation between thorium, xylenol orange (XO) and cethyltrimethyl ammonium bromide (CTAB) which is floated in the interface of the aqueous phase and n‐hexane by vigorous shaking. By discarding the aqueous solution and n‐hexane, the adsorbed ion‐associate (Th‐XO‐CTAB) on the wall of a separating funnel was dissolved in a small volume of ethanol solvent, and its absorbance was measured at 568 nm. The effects of different parameters such as pH, concentrations of HCl, XO, and CTAB, volume of n‐hexane, and standing and shaking time were studied. The calibration graph was linear in the concentration range of 2–200 ng mL−1 of thorium(r = 0.9994). The limit of detection (LOD) is 1.4 ng mL−1. The relative standard deviations (RSD) at 50 and 175 ng mL−1 of thorium were 2.5% and 1.0% (n = 7), respectively. The method was successfully applied to the determination of thorium in gas mantel samples.
Photoinduced Polymerization for Entrapping of Octadecylsilane Microsphere for Capillary Liquid Chromatography
Authors: Zhang Yu‐Ping , Deng Pu‐Hong , Xu Ming‐Lu , Wei Xin‐Jun , Tang Bo
Published: May 2015

A short length of a sol‐gel monolith was initially prepared as the temporary frit in a 100 μm inner diameter fused‐silica capillary by an in situ photopolymerization. The packed 4 μm octadecylsilane particles were then immobilized within the identical sol‐gel solution through the same photopolymerization process. The prepared fritless capillary column was examined for the chromatographic performance by the self‐developed capillary liquid chromatography system. Baseline separation of the model analytes was achieved including thiourea, benzene, toluene and ethylbenzene with the lowest theoretical plate height about 66 μm for the retained component. A scanning electron micrograph was used to characterize the temporary frit and entrapped microspheres. The inorganic polymer matrix in the microsphere‐packed column functioned to link microspheres at specific sphere‐sphere and sphere‐capillary contact points. Furthermore, the stability and porosity of the fritless column were systematically investigated by a simple flow method.
Construction of a New Uranyl‐Selective Electrode Based on a New Ionophore: Comparison of the Effect Additive on Electrode Responses
Authors: Shokrollahi A. , Ghaedi M. , Montazerozohori M. , Khanjari N. , Najibzadeh M.
Published: May 2015

A new plasticized PVC uranyl‐selective electrode based on a bis(2‐hydroxyacetophenone)ethylenediimine (BHAED) carrier by the direct coating of the membrane ingredients on the surface of a graphite disk electrode is reported. The electrode displayed high selectivity for uranyl ion toward a number of inorganic ions. The influence of the membrane compositions and pH, the effect of lipophilic cationic and anionic additives and plasticizer on the response properties of the electrode were investigated. The electrode exhibited a Nernstian slope of + 29.3 ± 1.2 for the uranyl ion concentration in the range of 5.0 × 10−6 −0.05 M with detection limits of approx. 2.0 μM. The potentiometric responses of the electrode are independent of pH over the range of 3.0–4.5 with satisfactory reproducibility. The sensor has response times of <5 s and can be used for at least 2 months without considerable divergence in potential.
An Efficient Protocol for the Synthesis of N‐Alkyl‐ and N‐Arylimides Using the Lewis Acidic Ionic Liquid Choline Chloride·2ZnCl2
Authors: Xie You‐Teng , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching
Published: May 2015

Lewis acidic ionic liquid choline chloride·2ZnCl2 is shown to be for the first time an excellent medium and efficient catalyst for the synthesis of N‐alkyl‐ and N‐arylimides in good yields under mild conditions.
Preparation, Antibacterial Activity and Absorption Spectra of Pyrazolo‐Oxadiazine Cyanine Dyes
Authors: Eissa Fayez M.
Published: May 2015

A new pyrazolo[4,3‐e]‐1,3,4‐oxadiazine heterocyclic ring system was prepared and employed to synthesize cyanine dyes of different methine types, including monomethine (simple cyanine) and trimethine (carbocyanine). The antibacterial activity of all the newly synthesized compounds was investigated against some bacterial strains. The electronic absorption spectra of the dyes were studied in absolute ethanol. The structure of all the synthesized compounds was identified via elemental and spectroscopic analysis.
Gd(OTf)3‐[Bmim][PF6]: A Novel and Recyclable Catalytic System for the Synthesis of Quinolines
Authors: Wu Jian‐Long , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching
Published: May 2015

A mild and efficient route for the synthesis of quinolines and polycyclic quinolines utilizing Gadolinium triflate (Gd(OTf)3) as a novel catalyst via Friedländer annulation in ionic liquid 1‐n‐butyl‐3‐methyl‐imidazolium hexafluorophosphate [Bmim][PF6] under mild conditions was described.
Theoretical and Experimental 27Al NMR Chemical Shift Studies on End‐Group Aluminates Linked to Different Silicate Species
Authors: Azizi S. Naser , Ehsani‐Tilami S.
Published: May 2015

Aluminium‐27 nuclear magnetic resonance spectroscopy (27Al NMR) does not yield fully resolved spectra for end‐group aluminates attached to different silicate species. For example, the chemical shifts of all q1 (end‐group aluminates) lying in the range δ ≈ 72.2–77 ppm are observed on average at δ ≈ 74.6 ppm in an NMR spectrum. With the aim of better characterisation of different q1 linked units, we first made some attempts to resolve the signals that might arise from different q1 linkages through the application of suitable experimental methods and then followed up this work by applying some calculation methods. Some of the observed differences and evidence have not been previously detected experimentally, but were clearly apparent from our calculations (Table 1) as well as in our experimental data. Therefore, in such a situation, theoretical calculations of NMR chemical shifts can be very helpful and can provide some missing information.
Self‐Assembly and Structure of Cobalt(II) Complexes Using Diaminodiamide Ligands
Authors: Chao Min‐Shiun , Lu Horng‐Hwa , Tsai Ming‐Liao , Hsieh Tsung‐Hsuan , Lin Chien‐Min
Published: May 2015

The self‐assembly of Co(II) with two diaminodiamide ligands, 4,7‐diazadecanediamide and 4,8‐diazaundecanediamide, gave two different crystals, [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]Cl2 (1) [Co(C9H20N4O2)(Cl)(H2O)]·Cl·2H2O (2). Structures of 1 and 2 were characterized by single‐crystal X‐ray diffraction analysis. Structural data for 1 shows a novel type of binuclear complex with distorted octahederal coordination geometry around the Co atoms through the hydroxo bridges. By using inter‐connector N‐H···N hydrogen bonding interactions as building forces, each cationic moiety [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]2+ is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chain‐like structure. The chains are further connected into a 2D layer in a (4,4)‐topology via N‐H···Clfree hydrogen‐bonding interactions. Structural data for 2 indicate that the cobalt atom adopts a six‐coordinated N2O4 environment, giving a distorted octahedral geometry, where two N‐ and two O‐donor sets of ligand located at equatorial positions and one water and one chloride occupied at axial positions. Through NH···Cl‐Co and OH···Cl‐Co contacts, each cationic moiety [Co(C9H20N4O2)(Cl)(H2O)]+ in 2 is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to steric strain effect of the diaminodiamide ligand.
Paclitaxel‐Loaded Stabilizer‐Free Poly(D,L‐lactide‐co‐glycolide) Nanoparticles Conjugated with Quantum Dots for Reversion of Anti‐Cancer Drug Resistance and Cancer Cellular Imaging
Authors: Kuo Wen‐Shuo , Ku Yu‐Cian , Sei Hei‐Tin , Cheng Fong‐Yu , Yeh Chen‐Sheng
Published: May 2015

We prepared the PLGA‐loaded anti‐cancer drug and coated it with quantum dots to make it a dual‐function nanoparticles, and analyzed its potential use in cellular imaging and curing cancers. Two cancer cell lines, paclitaxel‐sensitive KB and paclitaxel‐resistant KB paclitaxel‐50 cervical carcinoma cells, were the relativistic models for analysis of the cytotoxicity of free paclitaxel and paclitaxel‐loaded PLGA conjugated with quantum‐dot nanoparticles. The paclitaxel‐loaded PLGA conjugated with quantum dots nanoparticles were significantly more cytotoxic than the free paclitaxel drug in paclitaxel‐resistant KB paclitaxel‐50 cells. This might have been because the cancer cells developed multi‐drug resistance (MDR), which hampered the action of free paclitaxel by pumping its molecules to extracellular areas. Addition of verapamil, a P‐glycoprotein inhibitor, reversed the MDR mechanism and significantly reduced KB paclitaxel‐50 cell viability. As a result, KB paclitaxel‐50 was highly associated with MDR on the cell membrane. The cytotoxicity results indicated that PLGA nanoparticles served as drug carriers and protected the drugs from MDR‐accelerated efflux. Combined quantum dots with PLGA nanoparticles allowed additional functionality for cellular imaging.
Sonophysically‐Exfoliated Individual Multi‐Walled Carbon Nanotubes in Water Solution
Authors: Su Jun‐Wei , Hsu Chuen‐Yuan , Fu Shu‐Juan , Guo Chian‐Hua , Lin Kuan‐Jiuh
Published: May 2015

We report the sonophysically‐exfoliated methods access to the preparation of homogeneous‐free multi‐walled carbon nanotubes (MWCNTs) in water solution. Highly stable, uniform, individual MWCNTs are entirely performed through sodium dodecylsulfate surfactants by means of a tip sinicator. HRTEM images show that the crystalline finger walls of individual CNTs are apparently observed. Raman spectrum of MWCNTs shows that the so‐called G'‐band, associated with metallic electronic structure, was significantly observed at 2644 cm−1 with full‐width at half‐maximum of 262 cm−1, indicating that the sonication physical methods do not alter their electric properties. Owing to its easy‐to‐use procedure and low cost of implementation, this approach could lead to the commercial viability of the large‐scale MWCNTs processing.
Stabilizer‐Free Poly(lactide‐co‐glycolide) Nanoparticles Conjugated with Quantum Dots as a Potential Carrier Applied in Human Mesenchymal Stem Cells
Authors: Kuo Wen‐Shuo , Hwang Shiaw‐Min , Sei Hei‐Tin , Ku Yu‐Cian , Hsu Lee‐Feng , Cheng Fong‐Yu , Hsieh Patrick Ching‐Ho , Yeh Chen‐Sheng
Published: May 2015

We report that human mesenchymal stem cells (hMSCs) were successfully labeled with poly(lactide‐co‐glycolide) nanoparticles (PLGA NPs) surface‐conjugated quantum dots (QDs) (PLGA‐QD NPs) via endocytosis pathway. These NPs were not toxicity even treated with PLGA‐QD NPs at high concentrations for at least four weeks. Besides, PLGA‐QD NPs‐labeled hMSCs did not change their proliferation and differentiation capability toward the cell fates of adipocytes, osteocytes, and chrondrocytes. It's known that PLGA has been widely employed to act as delivery carrier which encapsulates drugs and releases them under a controlled way. Currently, we have also demonstrated that FITC‐loaded PLGA‐QD NPs degraded in hMSCs to achieve intracellular release of FITC. The aim of this research is to investigate viability, proliferation and differentiation capability and the potential for gene delivery of MSCs labeled with PLGA‐QD NPs. In addition to PLGA‐QD NPs, QDs alone were used to serve as a control set for comparison.
Solid Phase Extraction of Lead(II) by Sorption on Grinded Eucalyptus Stem and Determination with Flame Atomic Absorption Spectrometry
Authors: Mousavi Hassan Zavvar , Aibaghi‐Esfahani Behzad , Arjmandi Azadeh
Published: May 2015

A sensitive and simple solid‐phase preconcentration procedure for the determination of trace amount of lead by flame atomic absorption spectrometry (FAAS) is developed. The method is based on the adsorption of Pb2+ on the column of fine grinded eucalyptus stem adsorbent, elution of the column by nitric acid and subsequent determination by FAAS. The effect of different variables such as pH, eluent type, flow rate and interfering ions on the recovery of the analyte was investigated and optimum conditions were established. The adsorption of lead onto fine grinded eucalyptus stem can formally be described by a Langmuir equation with a maximum adsorption capacity of 4.49 mg g−1. A preconcentration factor of 50 was achieved using the optimum conditions. The calibration graph was linear in the range 10–125 ng mL−1 of lead in the initial solution with r = 0.9982. The limit of detection based on 3Sb criterion was 4.5 ng mL−1 and the relative standard deviation for eight replicate measurements of 30 and 80 ng mL−1 of iron was 3.6 and 2.8%, respectively. The method was successfully applied to the determination of lead added to well, tap and wastewater samples.
Layered Zirconium(IV) Aminoethylphosphonate Intercalated with Horseradish Peroxidase for an Amperometric Biosensor
Authors: Liu Chang‐Hua , Guo Xiao‐Li , Yuan Ruo
Published: May 2015

Layered zirconium(IV) aminoethylphosphonate (ZrAEP) have been used as matrices for immobilization of horseradish peroxidase (HRP) to fabricate enzyme electrode for an amperometric biosensor. The biocompatible HRP–ZrAEP films were fabricated on gold electrode surface by electro‐co‐deposition method. The morphology of the HRP–ZrAEP composite was characterized by scanning electron microscopy (SEM). UV–vis spectroscopy indicated that the intercalated HRP retained its native structure after incorporation in the ZrAEP. The immobilized HRP at the HRP–ZrAEP films exhibited good electro catalytic responses to the reduction of hydrogen peroxide. The response time of the biosensor was less than 3 s, and the linear range is from 2.5 × 10−6 to 3.22 × 10−3 M, with a detection limit of 7.0 × 10−7 M (S/N = 3). The Michaelis–Menten constant (KappM) value is estimated to be 2.21 mM. In addition, the obtained biosensor possesses high sensitivity, good stability and reproducibility.
Study on Synthesis, Characteristics and Catalysis Properties of Novel Chiral Metal Complexes Catalysts for 1,3‐Dipolar Cycloaddition Reactions of Nitrone with Electron‐Rich Alkene
Authors: You Jun , Liu Bo , Wang Yi
Published: May 2015

As a new class of potential catalysts for 1,3‐dipolar cycloaddition reactions, fourteen L‐amino acid Schiff base Cu(II) and Ti(IV) complexes were synthesized, characterized, and evaluated for their catalytic activities in the reaction between C,N‐diphenylnitrone and electron‐rich ethyl vinyl ether under both homogeneous and in situ conditions. The methods for preparation and utilization of the catalysts were elucidated in detail, and the results of the catalytic reactions were described and discussed as well. Excellent reaction results were found in the presence of some catalysts (20 mol%) with > 90% endo‐isoazolidines produced, compared with predominantly exo‐isoazolidine produced without a catalyst. In addition, the reaction rate is found to be enhanced remarkably by a Cu(II) complex Schiff base catalyst at room temperature.
Can be Azo Dyes Obtained by Grinding under Solvent‐Free Conditions?
Authors: Noroozi‐Pesyan Nader , Khalafy Jabbar , Malekpoor Zahra
Published: May 2015

The solid‐solid reactions of some electron‐donors with sulfanilic acid in the presence of solid sodium nitrite afford azo dyes by self‐catalyzed diazotization of sulfanilic acid (2) under solvent‐free conditions with moderate yields. Also the reactions of some electron‐donors with diazotization of o‐nitroaniline (5), m‐nitroaniline (6) and p‐nitroaniline (7) in the presence of solid sodium nitrite catalyzed by p‐toluenesulfonic acid (PTSA) afford azo dyes under solvent‐free conditions in good yields. This new method totally avoids the use of acids, alkalies, and toxic and/or expensive solvents in diazotization and diazo coupling reactions.
Synthesis and Application of Some Alkali‐Clearable Azo Disperse Dyes Based on Naphthalimide Derivatives
Authors: Parvizi P. , Khosravi A. , Moradian S. , Gharanjig K.
Published: May 2015

A series of naphthalimide‐based alkali‐clearable azo disperse dyes containing a fluorosulfonyl group was synthesized. 4‐Fluorosulfonylaniline, 4‐fluorosulfonyl‐2‐nitroaniline and 6‐chloro‐4‐fluorosulfonyl‐2‐nitroaniline as the diazo components were prepared from N‐acetylsulfanilyl chloride and were subsequently coupled with 4‐hydroxy‐N‐3‐methoxypropyl‐1, 8‐naphthalimide. The synthesized dyes and their intermediates were characterized by the use of DSC, FTIR, 1H NMR, 13C NMR, Mass spectroscopy and UV‐visible spectroscopic techniques. Spectrophotometric investigations of prepared dyes in different solvents were carried out in order to obtain their absorption maxima, molar extinction coefficients and solvatochromic effects. The obtained dyes were applied to polyester fabric by the HT method and exhibited good leveling, wash and sublimation fastnesses and moderate light fastness. The synthesized dyes showed that incorporated fluorosulfonyl group to these dyes can be converted to the dyes containing a water soluble sulfonate group in the relatively mild alkaline conditions.
(1,3‐Diphenyl‐1H‐Pyrazol‐4‐yl)‐Methylamine Analogues as Inhibitors of Dipeptidyl Peptidases
Authors: Hsu Tsu , Chen Chiung‐Tong , Tsai Ting‐Yueh , Cheng Jai‐Hong , Wu Su‐Ying , Chang Chung‐Nien , Chien Chia‐Hui , Yeh Kai‐Chia , Huang Yu‐Wen , Huang Chen‐Lung , Huang Chung‐Yu , Wu Ssu‐Hui , Chiang Yi‐Kun , Wang Min‐Hsien , Chao Yu‐Sheng , Chen Xin , Jiaang Weir‐Torn
Published: May 2015

A number of pyrazole compounds reported in literatures elicit anti‐hyperglycemic effects. By modifying the side chain of the heterocyclic skeleton, a new chemical class of DPP‐IV inhibitors structurally derived from the (pyrazol‐4‐yl)‐methylamine scaffold have been discovered and evaluated the biological activities of these inhibitors against DPP‐IV, DPP8, DPP‐II and FAP. The SAR studies showed the (1,3‐diphenyl‐1H‐pyrazol‐4‐yl)‐methylamines with 2,4‐dichloro substituents at the 3‐phenyl ring selectively preferred as DPP‐IV inhibitors, whereas with difluoro substituents at the 3‐phenyl ring selectively preferred as DPP8 inhibitors. The binding mode of representative compound 15h at the active site of DPP‐IV was predicted by computer model. In additional, 15h exhibited the ability to significantly decrease the glucose excursion in mice.
Improved Preparation of 3,3′,4,4′‐Tetramethyldiphenylethane by Self Coupling Reaciton in Aqueous Media
Authors: Hu Yu‐Lin , Lu Ming , Liu Qi‐Fa , Ge Qiang
Published: May 2015

In this article, 3,3′,4,4′‐tetramethyldiphenylethane was obtained in 86.5% total yield by self coupling reaction of 3,4‐dimethylbenzyl chloride catalyzed by Cu/Cu2Cl2/PEG‐600 and promoted by iron in aqueous media and the starting material 3,4‐dimethylbenzyl chloride was prepared by chloromethylation of o‐xylene in CTAB micellar catalytic system. Compared to other synthetic methods, the improved method not only enhanced the yield, but also made the operating units easy workup. The mechanisms of the chloromethylation and the self coupling were proposed. The structures of the products were confirmed by Elemental analysis,1H NMR and13C NMR or compared with authentic samples.
Ultrasound Assisted Synthesis of Coumarin Thioglycopyranoside Derivatives
Authors: Yu Lei , Gao Jian‐Fang , Cao Ling‐Hua
Published: May 2015

The methyl coumarins reacted with N‐bromo‐succinimide gave compounds (a∼c) which on further reacted with various peracetyl sulfhydryl glycose (1∼3) afforded a series of novel coumarin thioglycopyranoside compounds (1a∼1c, 2a∼2c, 3a∼3c). And when used ultrasonic irradiation, this method offered several advantages such as good yields and short reaction time than the silent reaction. All the new compounds were characterized on the basis of the IR, 1H NMR, 13C NMR and elemental analysis.
Facile Access to Benzothiazole‐Containing Pyrrolo[1,2‐a]quinolines and Pyrrolo[2,1‐a]isoquinolines via Nitrogen Ylides
Authors: Dawood Kamal M. , Ragab Eman A. , Khedr Nabila A.
Published: May 2015

Quinoline and isoquinoline react with 2‐(bromoacetyl)benzothiazole (1) in dry benzene to give the corresponding quinolinium and isoquinolinium salts 2 and 10 which undergo base‐mediated [3+2] 1,3‐dipolar cycloaddition with some acetylene and ethylene derivatives to give the corresponding benzothiazole‐containing pyrrolo[1,2‐a]quinoline and pyrrolo[2,1‐a]isoquinoline derivatives.
Efficient and Convenient Oxidation of Organic Halides to Aldehydes and Ketones Catalyzed by H5IO6/V2O5 in Ionic Liquid [bmpy][PF6]
Authors: Hu Yu‐Lin , Liu Xiang , Lu Ming , Jiang Hui
Published: May 2015

A mild, efficient, and eco‐friendly procedure for the oxidation of organic halides to aldehydes and ketones in good to high yields catalyzed by H5IO6/V2O5 in ionic liquid [bmpy][PF6] with no trace of overoxidation to carboxylic acids has been developed. The product can be isolated by a simple extraction with organic solvent, and the catalytic system can be recycled or reused without any significant loss of catalytic activity.
Study of Spectrophotometric Method for Determination of Trace Copper after Separation/Enrichment using Microcrystalline Absorption System
Authors: Tu Chang‐Qing , Wen And Xin‐Rong
Published: May 2015

The paper presents a novel method for the separation/enrichment of copper using microcrystalline absorption system prior to the determination of trace copper by spectrophotometry. The effects of different parameters, such as the dosages of KI and cetyltrimethyl ammonium chloride (CTMAC), various salts and acidity etc on the enrichment yield of Cu2+ have been investigated to select the experimental conditions. The possible enrichment mechanism of Cu2+ was discussed. The results showed that under the optimum conditions, cetyltrimethyl ammonium chloride cation (CTMAC+) reacted with I− to produce the microcrystalline matter (Ms‐M) of (CTMAC+ṁI−), Cu2+ in the solution was absorbed on the surface of Ms‐M of (CTMAC+ṁI−) and reacted with I− to form the precipitation of CuI, Cu2+ was completed enriched on the Ms‐M of (CTMAC+ṁI−). Thereby Cu2+ was separated completely from K+, Na+, Ca2+, Mg2+, Zn2+, Ni2+, Co2+, Mn2+, Fe2+ and Al3+ at pH 4.0. A new method of determination of trace copper was established. The proposed method has been successfully applied to the determination of trace Cu2+ in the sample of human hair, and the results agreed well with AAS method. The recoveries were 94.5% ∼ 105.6%, and the RSD was 2.2% ∼ 2.5%.
Simultaneous Determination of Captopril and Statins in API, Pharmaceutical Formulations and in Human Serum by RP‐HPLC
Authors: Sultana Najma , Arayne M. Saeed , Naveed Safila
Published: May 2015

Co‐administration of statins with angiotensin converting enzyme inhibitors is most common, since there is strong synergy between hypertension and hypercholesterolemia in terms of risk factors for the development of cardiovascular diseases. Rapid liquid chromatographic procedure proposed for analysis of captopril and statins in pharmaceutical preparations and human serum using acetonitrile:water (60:40 v/v) as a mobile phase, adjusting pH to 2.9 with UV detection at 230 nm. The advantages of this method include good and rapid separation, well resolved peaks, and only a small amount of sample is required for assay and adequate precision. The method showed good linearity in the range of 2.5‐100 μgmL−1 for captopril and 0.625‐25 μgmL−1 for statins with a correlation coefficient of 0.9999. The recovery of captopril and statins (rosuvastatin, atorvastatin and simvastatin) was > 99.9% and > 99.3%, respectively. The proposed method may be used for the quantitative analysis of captopril and statins alone or in combination in bulk drugs, dosage formulations and in human serum.
Thermal Study in Solid State of Zn(II)‐Diclofenac Complex: Behavior Kinetic of the Dehydration, Transition Phase and Thermal Decomposition
Authors: Kobelnik Marcelo , Quarcioni Valdecir Ângelo , Ribeiro Clóvis Augusto , Capela Jorge Manuel Vieira , Dias Diogenes Dos Santos , Crespi Marisa Spirandeli
Published: May 2015

The dehydration, thermal decomposition and transition phase stage of Zn(II)‐diclofenac compound were studied by simultaneous TG‐DTA and DSC techniques. The TG and DSC curves of this compound were obtained with the mass of sample of 2 and 5 mg. Additionally, DSC curves were carried out in opened and closed α‐alumina pans under static and nitrogen atmosphere. The DTA and DSC curves show that this compound possesses exothermic transition phase between 170‐180 °C, which it is irreversible (monotropic reaction). The kinetics study of this transition phase stage was evaluated by DSC under non‐isothermal conditions. The obtained data were evaluated with the isoconversional method, where the values of activation energy (Ea / kJ mol−1) was plotted in function of the conversion degree (α). The results show that due to mass sample, different activation energies were obtained. From these curves a tendency can be seen where the plots maintain the same profile for closed lids and almost run parallel to each other.
Electrochemical Characteristics of a Copper Hexacyanoferrate (CuHCNF) Modified Composite Carbon Electrode and Its Application toward Sulfite Oxidation
Authors: Majidi Mir Reza , Asadpour‐Zeynali Karim , Shahmoradi Keyvan , Shivaeefar Yadollah
Published: May 2015

The sol‐gel technique was used to construct copper hexacyanoferrate (CuHCNF) modified composite ceramic carbon electrodes (CCEs). The modified CCE was prepared manually by carefully mixing the dispersed graphite powder with Cu powder. Copper hexacyanoferrate (CuHCNF) film has been deposited on the surface of CCE by a simple electroless dipping into a potassium hexacyanoferrate solution method. The cyclic voltammograms of the resulting surface modified CCE under optimum conditions show a well‐defined redox couple due to the K2CuII [FeIII/II(CN)6] system. The electrochemical properties and stability of the modified electrode were investigated by cyclic voltammetry. The effect of different alkali metal cations in the supporting electrolyte on the behavior of the modified electrode was studied and the transfer coefficient (α) and charge transfer rate constant (ks) for the electron transfer between the electrode and modifier layer were calculated. The experimental results show that the peak potential and peak current vary with different alkali metal cations. An extensive study showed that the response of the modified electrode is not affected within a pH range of 2‐8. The modified electrode was used for electrocatalytic determination of sulfite in hard sugar sample.
Study on the Thermochemical and Kinetic Characteristics of Alkali Treated Rice Husk
Authors: Markovska I. G. , Bogdanov B. , Nedelchev N. M. , Gurova K. M. , Zagorcheva M. H. , Lyubchev L. A.
Published: May 2015

The effective utilization of waste rice husk requires detailed studies on the kinetics and mechanism of their thermal and chemical treatment. The present work is a comparative study on the thermo‐chemical and kinetic characteristics of thermal degradation of raw and treated with NaOH rice husk. The optimal conditions for extraction of SiO2 from rice husk in the form of Na2SiO3 were determined using thermal analysis (TA), scanning electron microscope (SEM) and elemental analysis. The experiments were carried out under conditions of non‐isothermal heating in air and nitrogen atmosphere. Using different kinetic models, the values of the effective kinetic parameters, characterizing the destruction process were determined.
Simultaneous Determination of Hesperidin, Ferulic Acid, Cinnamic Acid and Cinnamaldehyde in Chinese Tonic Wine by High Performance Liquid Chromatography
Authors: Lin Iung‐Jr , Cham Thau‐Ming , Wu Shou‐Mei
Published: May 2015

This study aims to establish a HPLC method for the simultaneous determination of hesperidin (HE), ferulic acid (FA), cinnamic acid (CA) and cinnamaldehyde (CAD) in a Chinese tonic wine, Ma‐Zu‐Wan‐Show‐Yao‐Jyo. After filtering the tonic wine, the filtrate was separated on a C18 column (250 × 4.6 mm, 5 μm) by gradient elution of acetonitrile‐aqueous solution. The regression equations were linear (r ≥ 0.9999) in the range of 1.5‐150.0 μg/mL for HE, 0.3‐60.0 μg/mL for FA, 0.06‐6.0 μg/mL for CA, and 0.1‐80.0 μg/mL for CAD. The relative standard deviation and relative error were less than 5.0% and 4.0%, respectively, for intra‐ and inter‐day analyses. The limits of detection (LOD) were 0.6, 0.075, 0.012 and 0.02 μg/mL for HE, FA, CA and CAD (S/N = 3, 20 μ1 injection) respectively. This method can be used to standardize the quality control of Chinese tonic wine to ensure accuracy and efficiency in the future.
A New Farnesene Derivative and Other Constituents from Senecio Cannabifolius
Authors: Xie Wei‐Dong , Weng Cheng‐Wu , Gao Xue , Zhao Hong , Row Kyung‐Ho
Published: May 2015

Anew farnesene derivative, 7R*,10S*‐epoxy‐3E,5E‐farnesadien‐1,2,11‐triol, along with eight known compounds was isolated from the aerial parts of Senecio cannabifolius. Their structures were established on the basis of spectroscopic methods.
Review of Morphology Dependent Charge Carrier Mobility in MEH‐PPV
Authors: Inigo A. R. , Huang Y. F. , White J. D. , Huang Y. S. , Fann W. S. , Peng K. Y. , Chen S. A.
Published: May 2015

Charge carrier mobility in poly(2‐methoxy,5(2′‐ethyl‐hexyloxy)‐p‐phenylene vinylene) (MEH‐PPV) films were measured as a function of temperature and electric field parallel and perpendicular to the substrate for devices prepared from different solvents and under different processing conditions. Bulk structural morphology was characterized by various X‐ray diffraction measurements such as wide angle, small angle and X‐ray reflection. Surface morphology was characterized using various scanning probe microscopic techniques. Mobilities were found to follow Gaussian disorder model (GDM) and to be highly anisotropic not only depending on the solvents used but also on the film preparation method such as spin‐coating or drop‐casting. While no direct correlation was found between charge carrier mobility and photoluminescence, charge transport parameters were correlated with structural morphology.
1H NMR Spectroscopic Study of the Solution Structure of a Conjugated Polymer
Authors: Rahman M. Habibur , Chen Hsin‐Lung , Chen Show‐An , Chu Peter P. J.
Published: May 2015

The structure of poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) solutions with a number of common deuterated organic solvents was studied by means of 1H NMR spectroscopy. The resonance bands of the polymer backbone protons appear at much lower frequencies in CDCl3 compared to their positions in aromatic solvents. This has been attributed to the π‐π self‐stacking interaction of the polymer segments in the aliphatic solvent, which is replaced by a polymer‐solvent π‐π interaction in the aromatic solvents. In mixed solvent systems with an aliphatic solvent component and an aromatic one, the intensities of the polymer resonances pass through a maximum at intermediate solvent compositions. This has been attributed to the minimum aggregation tendency of the polymer at these solvent compositions. The results suggest that a mixed solvent system constituting an aliphatic component and an aromatic component might be a choice for casting films of hairy‐rod type conjugated polymers if minimization of aggregate domains in the films is desired.
A Single Molecule FRET Study of Formation of RNA Polymerase II Elongation Complex on Passivated Surface
Authors: Lin Yen‐Chen , Lin Bo‐Lin , Setiawan Tommy , Chang Chia‐Chi , Yen Chi‐Fu , Chang Wei‐Hau
Published: May 2015

RNA polymerase II (pol II) is an essential enzyme that transcribes protein‐coding genes. It is of rudimentary and medical importance to understand the mechanisms of pol II transcription. By passivating fused‐silica surface with biologically‐friendly polyethylene glycol (PEG), we immobilized a RNA‐primed double‐stranded DNA, termed DNA/RNA scaffold, to build a single molecule transcription assay using FRET (fluorescence resonance energy transfer) signals from a donor on DNA and an acceptor on RNA as readouts, which allowed us to monitor how pol II assembles with the DNA/RNA scaffold with a total internal reflection fluorescence microscope. Here, our single molecular FRET assay shows that the DNA/RNA scaffold assumes heterogeneous conformations in the absence of pol II but retains a unique conformation in the presence of pol II, indicated by a single‐valued FRET value consistent with the RNA engaging in the pol II's RNA exit channel. Our study of pol II interacting with DNA/RNA offers an example for demonstrating that the single FRET assay is powerful in the following aspects: (1) it improves the spatial resolution of a few hundreds of nanometers, limited by optical diffraction on an ordinary fluorescence microscope, to nanometers; (2) it provides dynamical information with temporal resolution set by fluorescence microscopy instrumentation; and (3) it allows sorting of single molecules to reveal the heterogeneity, averaged out by bulk measurements. Such a single molecule FRET transcription assay can be readily extended to visualize nascent RNA extension in real‐time with the supply of NTPs, or be applied to dissect the architecture of various kinds of RNA polymerases, including pol I and pol III, the relatives of pol II.
Synthesis of Silver Nanoprisms and Nanodiscs an Applications in Fluorescence Blinking Suppression
Authors: Yu Pyng , Huang Jane , Yuan Chi‐Tsu , Tang Jau
Published: May 2015

In this work we investigated the influence of reagents in the synthesis of triangular silver nanoprisms through direct chemical reduction. We identified the chemical role of each reagent, i.e. H2O2, poly(vinylpyrrolidone) (PVP) and NaBH4, by systematically varying one reagent concentration while keeping the concentration of other reagents constant. We also discuss the applications of nanoprisms in blinking suppression of single semiconductor quantum dots. In addition, we also investigated the synthesis of silver nanodiscs through the reconstruction of triangular nanoprisms using halide ions. The results from different halide ions presented the different face‐selective etching rates on the well‐identified facet in the silver nanoprism.
Facile and Efficient Amination of Organic Halides Catalyzed by Copper Sulfate in PEG1000‐DIL/Methylcyclohexane Temperature‐Dependent Biphasic System
Authors: Hu Yu‐Lin , Wang Peng‐Cheng , Chen Tian , Lu Ming
Published: May 2015

A simple, efficient, and environmentally friendly procedure for the amination of organic halides catalyzed by CuSO4·5H2O in PEG1000‐DIL/methylcyclohexane temperature‐dependent biphasic system is described. The product can be easily isolated by a simple decantation, and the catalytic system can be recycled and reused without loss of catalytic activity.
UV Spectrophotometric Determination of Cu(II) in Synthetic Mixture and Water Samples
Authors: Lutfullah  , Sharma Saurabh , Rahman Nafisur , Azmi Syed Najmul Hejaz , Iqbal Bashir , Amburk Maisa Ismail Bilal Bait , Al Barwani Zuweina Masoud Hilal
Published: May 2015

A new and novel UV spectrophotometric method has been developed for the determination Cu(II) in synthetic mixture and water samples. The method is based on complex formation of Cu(II) with cefixime immediately in 1,4‐dioxan‐distilled water medium at room temperature. The complex showed maximum absorption wavelength at 336 nm. Beer's law is obeyed in the concentration range of 1.015‐8.122 μg mL−1 (Linear regression: A = 1.59 × 10−3 + 1.305 × 10−1 C) with apparent molar absorptivity (8.29 × 103 L mol−1cm−1) and Sandell's sensitivity (0.008 μg/cm2/0.001 absorbance unit). The limits of detection and quantitation for the developed method are 3.19 × 10−2 and 9.65 × 10−2 μg mL−1, respectively. Interferences due to Mn(II), Ca(II), Mg(II), Cd(II), Al(III), Pb(II), Zn(II), Fe(II), Fe(III), Ni(II), Cr(III), Hg(II) and As(III) was investigated. Nine cations do not interfere in the determination of Cu(II). Proposed method was successfully applied to the determination of Cu(II) in synthetic mixture, sea and well water samples.
Interaction of Di‐ and Triorganotin(IV) Compounds with Carboxylate Ligand: Synthesis, Spectral Characterization, Semi‐Empirical Study and In Vitro Antimicrobial Activities
Authors: Shahzadi Saira , Ali Saqib , Shahid Khadija , Yousaf Muhammad , Sharma Saroj K. , Qanungo Kushal
Published: May 2015

Di‐ and triorganotin(IV) complexes with the general formulae RnSnL4‐n, where R = Me, n‐Bu, Ph and L = 2‐[(2′‐methylphenylamido)]benzoic acid have been synthesized by the reaction of triethylammonium salt of 2‐[(2′‐methylphenylamido)]benzoic acid with di‐ and triorganotin chloride in dry toluene. All the synthesized complexes were characterized by elemental analysis, FT‐IR, multinuclear (1H, 13C, 119Sn) NMR, mass spectrometry and semi‐empirical study to assess the binding mode of 2‐[(2′‐methylphenylamido)]benzoic acid. The diorganotin(IV) derivatives are assessed to adopt distorted octahedral and triorganotin(IV) have linear polymeric trigonal bipyramidal structures in which 2‐[(2′‐methylphenylamido)]benzoic acid is a monoanionic bidentate, coordinating through C(O)O group. This coordination behaviour is also confirmed by semi‐empirical study. The isotopic effect of tin was studied by comparison of experimental data with the simulated isotopic pattern using the Chemtool software package. The insecticidal, antileshmanial, antibacterial, antifungal and cytotoxicity of the synthesized compounds are also reported. Some complexes exhibit good activities comparable to that of standard drugs. Furthermore, triorganotin(IV) derivatives exhibit significantly better activities than the diorganotin(IV) derivatives and have a potential to be used as drug.
Complexes of Cu(II) and Ni(II) with Bis(Phenylthiosemicarbazone): Synthesis, Spectral, EPR and in Vitro ‐ Antibacterial and Antioxidant Activity
Authors: Rao Y. Subba , Prathima B. , Reddy S. Adinarayana , Madhavi K. , Reddy A. Varada
Published: May 2015

The synthesis of Cu(II) and Ni(II) complexes with 2,6‐diacetylpyridine bis(4‐phenyl‐3‐thiosemicarbazone) (L) ligand have been reported. The ligand was characterized by elemental analysis and spectral (IR and 1H NMR) studies and its complexes were characterized by electronic, UV/VIS, EPR and IR studies. The room‐temperature EPR spectrum of Cu(II) complex was recorded and the analysis of its spectrum gave {g} tensor with g1 = 2.25, g2 = 2.15, and g3 = 2.07 which were of distorted octahedral structure. The electronic spectrum of Ni(II) complex indicated the octahedral geometry around the Ni(II) ion. Their antibacterial activities were evaluated by the diameter of zone of inhibition (mm) against four bacteria such as B. subtilis, S. aureus, E. coli and K. pneumonia. The ligand and the 6‐coordinate Ni(II) complex did not inhibit the growth of the test organisms, while the Cu(II) complex showed good antibacterial activity than parent ligand against the same bacteria. The free ligand and its metal complexes have been tested for in vitro ‐ antioxidant activity by reduction of 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) and iron induced lipid peroxidation using rat brain homogenate. The ligand exhibited potent in vitro ‐ antioxidant activity than its Ni(II) and Cu(II)complexes.
Silica Chloride Catalysed One‐pot Synthesis of 13‐Aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐12(13H)‐ones under Solvent‐free Conditions
Authors: Wu Li‐Qiang , Yang Li‐Min , Wang Xiao , Yan Fu‐Lin
Published: May 2015

A simple and facile synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐12(13H)‐ones has been accomplished by the one‐pot condensation of β‐naphthol, aldehydes, and 2H‐indene‐1,3‐dione under solvent‐free conditions in the presence of the heterogeneous catalyst silica chloride.
Chemical Composition and Bioactivity of Essential Oil of Seed and Leaf from Alpinia speciosa Grown in Taiwan
Authors: Ho Jiau‐Ching
Published: May 2015

The essential oil, methanolic and aqueous extracts of the seeds and leaves of Alpinia speciosa (Wendl.) K. Schum. (Zingiberaceae) were assayed for their mushroom tyrosinase inhibition, larvicidal effect, antioxidant property and antimicrobial activity. The main components of the seeds were camphor, sabinene, (Z)‐β‐ocimene, 1,8‐cineole, terpinen‐4‐ol and α‐pinene, while the leaves contains camphor, sabinene, γ‐terpinene, terpinen‐4‐ol and α‐terpineol. The seed and leaf oil exhibited concentration‐dependent inhibition of mushroom tyrosinase, giving 74 and 81% inhibition at 1000 ppm, respectively. The seed oil exhibits the mosquito larvicidal activity with 2 h and 24 h LC50 value of 125 and 87 ppm, respectively, whereas the leaf oil shows larvicidal activity with 2 h and 24 h LC50 value of 64 and 32 ppm, respectively. The methanolic and aqueous extracts of A. speciosa show remarkable antioxidant effect. This activity can be attributed to the presence of the phenolic compounds. The essential oil of A. speciosa exhibits a strong broad‐spectrum antimicrobial activity against all test organisms. The seeds and leaves of A. speciosa could be considered as a natural tyrosinase inhibition, mosquito larvicidal, antioxidant and antimicrobial source.
Highly Regioselective Oxybromination in an Aqueous System Using SBA‐15 Supported Sulfated Zirconia Catalyst
Authors: Chen Ai‐Jan , Chen Xiao‐Rong , Mou Chung‐Yuan
Published: May 2015

SBA‐15 supported sulfated zirconia (SZ) catalysts were employed in many acid‐catalysis of reactions under mild condition because it is a strong solid acid with various Lewis and Brønsted acid sites. An oxybromination of aromatic substrates using hydrogen peroxide and ammonium bromide in the aqueous phase under mild temperature and near‐neutral pH condition over SZ was achieved. A good to excellent para‐selectivity was observed. The mesoporous silica SBA‐15 supported SZ possessed higher catalytic activity than self‐supported SZ because of larger surface area and pore size. The effect of the calcinations temperature was also investigated. The good catalytic performance of the SZ/SBA‐15 materials was attributed to high degree of dispersion of sulfate groups to give sulfated silica‐zirconia of (1) very good redox property and (2) high strength and high density of acid sites. The SZ/SBA‐15 catalyst may be re‐used several times without substantial loss of activity.
Analysis of Copper in an Aqueous Solution by Ion‐Exchange Concentrator and Laser‐Induced Breakdown Spectroscopy
Authors: Kim Taesam , Ricchia Michael L. , Lin Chhiu‐Tsu
Published: May 2015

Laser‐induced breakdown spectroscopy in composition analysis of materials has many advantages over other analytical methods. Its simple‐or‐no sampling procedure is a key advantage. The LIBS has been applied to liquid samples, although direct analysis of liquids is difficult because of weak plasma generation. An ion exchange membrane is used in this work to develop a real time monitoring method of metal ions in water. The chelating‐resin based filter membrane was used to capture and concentrate copper ions from water. The samples were filtered under reduced pressure for faster filtration. The captured copper ions on the membrane were analyzed by LIBS. A series of copper solutions and mixtures were examined to establish the proper analytical conditions. The plasma emission intensity of copper generated from the thin layer of the membrane was investigated to determine the spectroscopic parameters for a practical real‐time water monitoring. The copper ion collected on the membrane can be free of matrix effect from other ions in the original samples, and has provided the consistent analytical results in the mg/L concentration range. The laser power of each ablating pulse is very critical to obtain a proper analytical dynamic range, especially when the copper captured layer is thicker than the depth of one pulse laser can ablate. Tap water was used to analyze and evaluate the feasibility of this method. The amount of copper in the tap water was shown to depend on the retention time of water in copper pipes of the building pluming system.
The Use Ionic Liquid as the Eluent Additive for HPLC Separation of Ionic Dyes
Authors: Chen Hsiu‐Liang , Wei Guor‐Tzo
Published: May 2015

Reversed‐phase HPLC separation of ionic dyes (methylene blue, neutral red, methyl orange, and acid orange) with 1‐alkyl‐3‐methylimidazolium ionic liquids as the eluent additives was studied. The addition of ionic liquid to the eluent affects the resolution, peak shape and reproducibility of the retention of ionic solutes. The use of ionic liquids as the additives facilitates the separation of ionic dyes with a reversed‐phase HPLC. Baseline‐resolved separation of these dyes was achieved in 12 minutes when the mobile phase of acetonitrile‐water (28:72,v/v) contained 0.3‐2.0% (v/v) [emim][BF4]. The detection limits for the four dyes ranged from 4.45 to 10.0 μg/L for an injection volume of 20 μL. Apparently, ionic liquid is an effective mobile phase additive for the separation of ionic dyes in reversed‐phase HPLC separation.