bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon Nanotubes Coated Fiber for Solid‐Phase Microextraction of Bovine Fibrinogen and Bovine Serum Albumin
Authors: Tang Ping‐Ping , Cai Ji‐Bao , Su Qing‐De
Published: May 2015

Carbon nanotubes (CNTs) are a kind of novel and interesting carbon material which can be used for separation and purification. In this investigation, commercial solid‐phase microextraction (SPME) fibers (PDMS) were coated with single‐wall nanotubes (SWNTs) and multi‐wall nanotubes (MWNTs) to study their adsorption and extraction ability of proteins, and bovine fibrinogen (BFg) and bovine serum albumin (BSA) were selected as the target proteins. While MWNTs adsorbed more BFg than SWNTs, SWNTs adsorbed more BSA than MWNTs. CNTs can selectively adsorb BFg in certain conditions. The fibers coated with CNTs had advantages over traditional SPME fibers in selectivity and sensitivity. It could be used to separate BFg in bovine blood plasma and also purify BFg from it. The results show that the selectivity, sensitivity and reproducibility of this method are good for real sample analysis.
Separation of the Phenoxy Acid Herbicides and Their Enantiomers by Capillary Zone Electrophoresis in Presence of Highly Sulphated Cyclodextrins
Authors: Malik Ashok Kumar , Aulakh Jatinder Singh , Fekete Agnes , Schmitt‐Kopplin Philippe
Published: May 2015

The study of the chiral compounds and their fate in the environment is receiving an increasing attention — enantiomeric ratios are being measured and enantioselective degradation processes are being reported. It is particularly important with the toxic compounds like the pesticides, which are being freely used in the environment to control the harmful pests. Capillary zone electrophoresis was used for the chiral and mutual separation of four phenoxy acid herbicides using highly sulphated cyclodextrins (HSCD) in the buffer. The CE runs were performed with reverse polarity (anode in the outlet vial) using the acidic ammonium formate buffer (20 mmol, pH 3). Under these conditions of suppressed the electroendoosmotic flow (EOF), the analytes are mobilized to the anode by entering into host guest relation with the migrating negatively charged sulphated cyclodextrin. The phenoxy acid herbicides selected for the purpose were fenoprop, dicloprop, mecoprop and 2,4‐DB. The α‐HSCD and β‐HSCD have been tested as resolving agents in the CE for the separation of the enantiomers of the herbicides. Though the chiral separation of the dicloprop and mecoprop were achieved with α‐HSCD but it was not able to resolve fenoprop. With β‐HSCD the required base line separation was achieved. Potential difference selected was 10 kV. The limit of detection (S/N= 3) achieved in present case is 0.15 ppm for fenoprop, 0.14 ppm for dicloprop and mecoprop and 0.11 ppm for 2,4‐DB.
Investigation of the Reaction of Gold(III) with 2‐[2‐(4‐Dimethylamino‐Phenyl)‐Vinyl]‐1,3,3‐Trimethyl‐3H‐Indolium. Application for Determination of Gold
Authors: Serbin Rastislav , Bazel Yaroslav R. , Torok Marcel , Havel Josef , Balogh Ioseph S. , Kormosh Zholt O. , Holéczyová Gabriela , Andruch Vasil
Published: May 2015

A new, simple, rapid, sensitive, efficient and low‐cost spectrophotometric procedure for the determination of gold was developed. The method is based on the reaction of [AuCl4]− with 2‐[2‐(4‐dimethylaminophenyl)‐vinyl]‐1,3,3‐trimethyl‐3H‐indolium reagent to form a colored ion associate extractable by various organic solvents. The molar absorptivity of the ion associates is in the range (5.7–9.2) × 104 L mol−1 cm−1 depending on the extractant. Butyl acetate was chosen as the extractant. The optimum reaction conditions were established: pH 2–4, concentration of the dye reagent (0.8–1.5) × 10−4 mol L−1. The determination of gold is not hindered even by a 1000‐fold concentration of Ni and Co; a 500‐fold concentration of Pb and Zn; a 100‐fold concentration of Bi, Cu, Cd, Pt, Rh and Ru; or a 20‐fold concentration of Ag. The established method was applied to the determination of gold in model samples and enriched polymetallic ores.
Synthesis and Characterization of Novel Arylaldehyde (Arylketone)‐(4‐Substituted phenyl‐5‐Substituted phenoxy‐Methyl‐4H‐1,2,4‐Triazole‐3‐yl)‐Thiol Acetyl Hydrazones
Authors: Zhang Heng‐Wen , Li Yan‐Ping , Liu Chen‐Jiang , Li Hai‐Long , Sun Wen‐Li
Published: May 2015

Fourteen novel arylaldehyde (arylketone)‐(4‐substituted phenyl‐5‐substituted phenoxy‐methyl‐4H‐1,2,4‐triazole‐3‐yl)‐thiol acetyl hydrazone derivatives (5a‐5g, 6a‐6g) were synthesized by 4‐substituted phenyl‐5‐substituted phenoxy‐methyl‐1,2,4‐triazole‐3‐thione as starting material according to substructure link principle, followed by thioetherification, hydrazide hydrazone reaction. The structures of these compounds were confirmed by IR, 1H NMR and elemental analysis. Crystal structure of compounds 1b and 6d were determined by the X‐ray diffraction.
Geometric Effects on Conductance in Single Molecule Electron Transport Junctions
Authors: Hsieh Shang‐Chieh , Mai Fur‐Der , Jang Soonmin , Tang Hong‐Yi , Li Feng‐Yin
Published: May 2015

We studied electron transport properties of a dithiol‐benzene molecule covalently bonded between two gold electrodes by combining ab initio calculations for the central molecule and a green function method to calculate electron transport. Due to the large computational demand, this type of calculations usually involves certain ways of simplification. The simplification commonly used is to fix the contact surface of the electrodes by ignoring the disturbance of the Au contact surface by contacting with the central molecule, i.e. without scattering region relaxation. In this study, we intended to resolve the difference between models with and without the above simplification. The large conductance found in our models without scattering region relaxation is due to the highly symmetric arrangement of the Au contact surface and those layers near the contact. The disturbance of the Au contact surface by the contact of the central molecule is important since the increase of the Au‐S bond and the distortion of the Au atom on the FCC site can lower the transmission coefficient between the two electrodes. In order to obtain better results, the model should include scattering region relaxation. However, when such relaxation is not applicable or demands too much calculation resource, the center molecule of the electronic transport junction should be at least optimized by the calculation level including electronic correlation, i.e. post‐HF methods.
The π‐Bonding Trend in VIB M(CO)6 Observed by NMR Spectroscopy — A Natural Bond Orbital View
Authors: Wang Shao‐Pin , Yan Ker‐Ming , Hsu Wen‐Yi , Huang Min‐Ying , Wu Hui‐Ying
Published: May 2015

Analysis of carbonyl's 2π orbital populations, [2π], obtained by NMR relaxation time experiments of VIB M(CO)(ẽ6‐C6H6) reveals the 3d < 4d < 5d trend for M r̊ CO back‐donation, as reported values of [2π] for VIB M(CO)5(quinuclidine). The same analysis performed on Mn(CO)3(ẽ5C5H5) and Re(CO)3(ẽ5‐C5H5) also gives 3d < 5d order of back‐donation. The distinctive 3d ∼ 5d > 4d trend reported for VIB M(CO)6 has been investigated by second‐order perturbation theory analysis within the natural bond orbital (NBO) scheme to search for orbital‐based explanations. Besides the conventional dπ r̊ 2π donor‐acceptor (DA) interaction in the trend 3d < 4d < 5d, the other DA interaction arising from three‐center‐hyperbond (3CHB) hyperconjugation has been found in the trend 3d >> 5d ∼ 4d. Within the VIB M(CO)6 family, this 3CHB hyperconjugation is so much higher in Cr(CO)6 than in W(CO)6 as to render the overall 2π populations exhibiting the 3d ∼ 5d > 4d trend.
Improved Catalytic Performance of Pt Supported on Multi‐Wall Carbon Nanotubes as Cathode for Direct Methanol Fuel Cell Applications Prepared by Dual‐Stepped Surface Thiolation Processes
Authors: Chen Tsan‐Yao , Lin Tsang‐Lang , Chen Chien‐Chung , Chen Chieng‐Ming , Chia‐Fu Chen
Published: May 2015

This study develops a simple surface modification process for modifying the MWCNT surface by thiolation reaction after the conventional nitric acid treatment for strong interface attachment of Pt NPs and improved dispersion onto MWCNTs. The thiolated MWCNTs (Pt/MWCNTs) showed significant improvement of methanol electro‐oxidation activity compared with that treated only by nitric acid solution. The prepared electrode with thiolated MWCNTs was used as the cathode for assembling MEA for DMFC single‐cell applications. Testing results indicate that the thiolated MWCNT cathode can improve the power density of MEA by more than 300% (from 4.6 to 20.6 mW cm−2) compared with that treated only by conventional nitric acid reactions. The dual‐step modification process for MWCNT surface treatment showed significant improvement over the convention nitric acid treatment and can be successfully used in DMFC applications.
Preparation of Silica Supported Tin Chloride: As a Recyclable Catalyst for the Silylation of Hydroxyl Groups with HMDS
Authors: Niknam Khodabakhsh , Zolfigol Mohammad Ali , Saberi Dariush , Molaee Hajar
Published: May 2015

Silica‐supported tin chloride [SiO2‐Sn(Cl)4‐n] has been prepared by mixing tin chloride with activated silica gel in toluene under refluxing conditions for one day. A range of primary, secondary, and tertiary alcohols as well as phenolic hydroxyl groups were converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of silica‐supported tin chloride at room temperature. An excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups was also observed. This catalyst could be recycled and reused fifteen times without loss of efficiency.
Efficient Synthesis of Optically Pure (+)‐Bezene Diol Epoxide and (+)‐Conduramine A‐1
Authors: Chang Yuan‐Kang , Lo Hong‐Jay , Yan Tu‐Hsin
Published: May 2015

In this paper, we develop a concise approach to (+)‐benzene diol epoxide and (+)‐conduramine A‐1 based upon the utilization of the C2‐symmetric L‐tartaric acid as a chiral building block.
Molecular Structure and a Density Functional Theoretical Study on 2‐Nitroimino‐5‐Nitro‐Hexahydro‐1,3,5‐Triazine (NNHT)
Authors: Zhan Jiao‐Qiang , Ma Hai‐Xia , Xu Kang‐Zhen , Chen Yong‐Shi , Hu Rong‐Zu
Published: May 2015

2‐Nitroimino‐5‐nitro‐hexahydro‐1,3,5‐triazine (NNHT), was synthesized and its structure was determined by single‐crystal X‐ray diffraction. The crystal is monoclinic, space group P21/c with crystal parameters of a = 9.4031(13) Å, b = 8.5891(12) Å, c = 9.0200(13) Å, β = 91.213(2)°, V = 728.33(18) Å3, Z = 4, F(000) = 392, Dc = 1.734 g/cm3. The experimental geometry of NNHT was input to Gaussian‐03W program and optimized using DFT‐B3LYP/6‐311++G** method. The IR frequencies and NMR chemical shift were carried out and compared well with those of the experimental. The atomic net charges and the population analysis are discussed. The heat of formation (HOF) for NNHT was evaluated by designing an isodesmic reaction. The detonation velocity (D) and detonation pressure (P) were estimated by using the well known Kamlet‐Jacobs equation, based on the theoretical HOF.
Ultrasound‐Assisted One‐Pot Synthesis of Octahydroquinazolinone Derivatives Catalyzed by Acidic Ionic Liquid [Tbmim]Cl2/AlCl3
Authors: Niralwad Kirti S. , Shingate Bapurao B. , Shingare Murlidhar S.
Published: May 2015

Acidic ionic liquid [tbmim]Cl2/AlCl3 catalysed an efficient synthesis of octahydroquinazolinone derivatives under ultrasound‐irradiation. This method provides several advantages such as environment benign, high yields and simple work‐up procedure.
A New Spectrophotometric Method for the Determination of Ascorbic Acid Using Leuco Malachite Green
Authors: Tiwari Kishore K.
Published: May 2015

A new simple and sensitive and selective spectrophotometric method has been developed for the determination of ascorbic acid (AA) at trace level using a new reagent, leuco malachite green (LMG). AAreacts with potassium iodide‐iodate solution under acidic conditions to liberate iodine and the liberated iodine selectively oxidizes LMG to MG dye. The colour of the dye was measured at 620 nm. Beer's law is obeyed over the concentration range of 0.8–8 iμg μAA per 25 mL of final solution (0.032–0.32 ppm). The apparent molar absorptivity and Sandell's sensitivity of the method were found to be 2.98 × 105 l mol−1 cm−1, 0.0042 μg cm−2, and respectively. Statistical treatment of the experimental results indicates that the method is precise and accurate. The method is free from interference of common ions and many of the ingredients commonly found in pharmaceuticals. The reliability of the method was established by parallel determination against Leucocrystal violet (LCV) method. The method described was satisfactorily applied for the determination of AA in fruit juices, pharmaceuticals and biological samples.
Efficient Methyl Esterification Using Methoxyl Silica Gel as a Novel Dehydrating Reagent
Authors: Li Jian‐Guo , Peng Yan‐Qing
Published: May 2015

Methoxyl silica gel was prepared readily by the treatment of silica chloride with methanol. By using methoxyl silica gel as a dehydrating agent, carboxylic acids reacted with methanol in the presence of a protonic acid such as 12‐phosphotungstic acid afforded the corresponding methyl esters in excellent yields.
Photophysics of Single PPV Derivative Polymers
Authors: Liang J. J. , Hsu J. H. , Lim T. S. , White Jonathon David
Published: May 2015

Conjugated polymers are unique subjects composed of many excitons localized at individual segments. Migration of excitation is strongly correlated with the chain conformation. We studied the PPV derivative polymers, MEH‐PPV and DOO‐PPV, with different chain lengths to probe the relation between the conformation of, and exciton migration in, single polymers. Photo‐quenching of individual conjugated segments was used to provide information on the exciton migration process. A phenomenological model based on the polymer as a collection of conjugated segments has been developed to explain the observation. The purpose of this paper is not to provide an exhaustive account of research in the field but rather to emphasis the unique contributions of the group of Prof. W. S. Fann.
Thermodynamic and Kinetic Studies of a Stable Imperfect DNA Triplex by Spectroscopic and Calorimetric Methods
Authors: Wey Ming‐Tsai , Lyu Ping‐Chiang , Kan Lou‐Sing
Published: May 2015

An imperfect DNA triplex, containing a pyrimidine/purine duplex with two sites of purine/pyrimidine base pair inversions, is formed and recognized. The unusual triplex is examined for the possibility of triplex DNA formation in a living system by way of non‐ideal sequence matching. The duplex part of it consists of a DNA oligomer with 17 nucleotidyl units, 5′‐TTCTTCTGATTCTCTCC‐3′ (C), which has two purine bases flanked by fifteen pyrimidine bases. The sequence of oligomer C is picked from a segment of cell cycle protein cdc25 gene (696 to 712) in Pneumocystis jirovecii, a yeast‐like parasitic fungus, which can cause pneumonia (PCP) in patients with impaired immunity. The complementary oligomer, 5′‐GGAGAGAATCAGAAGAA‐3′ (W), forms a DNA duplex WC with C, accompanied by CG/GC and TA/AT base pair inversions, in contrast to homo pyrimidine/purine duplexes. A third strand, 5′‐CCTCTCTTAGTCTTCTT‐3′ (H), combines with WC, to give an imperfect, but stable, triplex WCH+.UV absorption, circular dichroism, and native gel electrophoresis mobility shift assay are used to monitor the reactions at each stage. The triplex is stable in mild acidic solution, with a 1:1:1 stoichiometric ratio and a UV melting temperature (Tm) of 47.3 °C at pH 4.5. Isothermal titration calorimetry (ITC) and surface Plasmon resonance (SPR) unravel the thermodynamic information (ΔH = −123.1 kcal mol−1, ΔS = −378 cal mol−1K−1 and ΔG = −10.5 kcal mol−1) and kinetic rate constants (ka = 3.71 × 104 M−1 s−1 and kd = 7.49 × 10−4 s−1), respectively, for the WCH+ triplex formation process. WCH+ is termed an imperfect triplex since it contains two non‐canonical, non‐purine/purine/pyrimidine or non‐pyrimidine/purine/pyrimidine, base triads in the middle. This is the first time an imperfect but stable triplex, containing two purine bases in the middle of a pyrimidine‐rich strand (H), is formed and studied. The fact that an imperfect but stable DNA triplex can be formed gives great promise for drug design through more flexible targeting capabilities with much less stringent requirements, e.g., designs against Pneumocystis jirovecii using triplex formation in our example.
Spectroscopic Study of Organic Light‐Emitting Polymers: A Review
Authors: Chang Railing , Hayashi Michitoshi , Lin S. H.
Published: May 2015

In this review paper, we theoretically investigate the optical properties of the organic light‐emitting polymer (OLEP). Despite of its enormous size, OLEP is described well by the oligomer model because of the imperfect backbone structure. By using the molecular exciton theory, we calculate the energy level of S1 states and Huang‐Rhys factor of oligomer which decrease with its chain length. The spectral profiles for oligomer thus can be readily calculated and used to explain the absorption and PL for OLEP in dilute solution with a chain length distribution described by a Gaussian function. Moreover we show that the luminescence of OLEP in high concentration solution as well as thin film is mainly contributed by the interchain states. In the ultrafast time‐resolved PL spectrum, we propose a model in which the dynamic processes such as energy transfer, charge transfer, and vibrational relaxation are treated in an equal‐footing manner, and find that in the high energy region the states in a thin film of OLEP is dominated by the intrachain species. In addition, we discuss the nonradiative transitions occurring in OLEP.
One‐Pot Three‐Component Synthesis of 6‐Bromoquinolines and 6‐Iodoquinolines
Authors: Wu Li‐Qiang , Wang Xiao , Ma Wei‐Wei , Yan Fu‐Lin
Published: May 2015

Three‐component one‐pot synthesis of some novel 6‐bromoquinolines 5a‐5h involving the treatment of 2‐aminobenzophenone, α‐methylene carbonyl compounds, and tetrabutyl‐ammonium tribromide was achieved, and this reaction was extended to the preparation of 6‐iodoquinolines 6a‐6e by a three‐component reaction 2‐aminobenzophenone, α‐methylene carbonyl compounds, and benzyltrimethylammonium dichloroiodate in the presence of ZnCl2.
A Simple Method to Prepare Methacrylate‐Based Capillary Monolithic Column Using Microwave Irradiation
Authors: Zhang Yu‐Ping , Chen Na , Gong Wen‐Jun , Yang Sheng‐Kai
Published: May 2015

A methacrylate‐based monolith was initially prepared in fused‐silica capillary, using microwave irradiation. The electrophoretic and chromatographic behaviors of the prepared capillary monolithic columns were comparatively evaluated in the modes of pressure‐assisted capillary electrochromatography, capillary electrochromatography and low pressure‐assisted liquid chromatography. Baseline separation of the model analytes was, respectively, achieved with the lowest theoretical heights up to 17.0 μm, 28.4 μm and 16.3 μm for thiourea. A scanning electron micrograph of a cross‐section of the capillary column showed that the monolith was formed in the center of the capillary and adhered to the column inner wall.
Determination of Magnesium and Calcium in Biological Samples by Potentiometric Stripping Analysis
Authors: Wu Xian‐Li , Zhou Hong‐Bi , Wang Shu‐Jie , Ye Bao‐Xian
Published: May 2015

A new and simple method for determination of calcium and magnesium in human plasma and hair samples was investigated by using potentiometric stripping analysis. The replacement reactions between Ca2+ and Zn‐EGTA (Ethylene glycol‐bis‐(2‐aminoethyl)tetraacetic acid) complex and between Mg2+ and Zn‐EDTA (Ethylenediamine tetraacetic acid disodium salt) complex were utilized. The determinations were carried out in NH4Cl‐NH3 buffer solutions of pH 9.54 for calcium and of pH 10.18 for magnesium, respectively. Potential and time data were digitally converted into dtdE−1, and E was plotted vs. dtdE−1. Quantitative analysis was carried out by the method of standard additions. Linearity for determination of magnesium was found to be in the range of 6∼120 μg L−1 with a correlation coefficient of 0.997 (n = 6); and for determination of calcium in the range of 10∼250 μg L−1 with a correlation coefficient of 0.995 (n = 6). The detection limit of 4 μ gL−1 was found for both magnesium and calcium determination. This proposed method has been used for determining calcium and magnesium in biological samples with good recoveries and well accord with the results of Inductively Coupled Plasma‐Atomic Emission Spectrometry (ICP‐AES).
Turning Low Barrier Hydrogen Bonds on and Off
Authors: Lankau Timm , Yu Chin‐Hui
Published: May 2015

The hydrogen bond in the [HDihH‐Fda]+ ion (HDih: 4,5‐dihydro‐1H‐imidazole, Fda: 1‐fluoro‐N,N‐dimethylmethaneamine) can be an ordinary single well hydrogen bond (HB) or a low barrier hydrogen bond (LBHB) depending on the orientation of the CH2F group in the Fda molecule. Both domains on the cluster's potential energy surface are well separated from each other by a 10 kcal/mol high barrier, which turns the CH2F group into a switch for the LBHB. The conformers with a LBHB are generally higher in energy than their counterparts with a standard HB, which suggests that the LBHB is not necessarily the more stable bond.
Preparation of Heteropoly Acid/Porous Hybrid Materials and Investigation of their Catalytic Behavior in the Synthesis of Perimidine
Authors: Zendehdel M. , Mobinikhaledi A. , Alikhani H. , Jafari N.
Published: May 2015

A series of hybrid heteropoly acids (HPA) were prepared. The HPA/NaY and HPA/NaY/MCM‐41 hybrids of the synthesized catalysts were characterized using XRD, BET, TGA, SEM and FT‐IR techniques. The results show that reasonable amount of HPA in HPA/NaY and HPA/NaY/MCM‐41 hybrids remains even after washing with water, which indicates that heteropoly anions were strongly bonded to the porous materials. The catalytic properties of the hybrid catalysts were examined for the preparation of 2‐(4‐nitrophenyl)‐2,3‐dihydro‐1H‐perimidine. The yield for perimidine by different catalysts was in order of HPA/NaY > HPA/NaY/MCM‐41 > NaY > HPA > MCM‐41.
Molecular Complexation between Iodine(III) Chloride and Meso‐tetraarylporphrins: Synthesis, Spectroscopic Characterization and Photoluminescence Study
Authors: Dehghani Hossein , Sahba Reyhaneh , Afrooz Malihe , Mollaei Halimeh
Published: May 2015

Iodine(III) chloride and free base para‐substituted meso‐tetraarylporphyrins (H2t(4‐Xp)p, X = OCH3, CH3,CH(CH)3, H, Cl) react at mild conditions for formation of [(ICl3)H2t(4‐Xp)p] molecular complexes. The very close correspondence between the UV‐VIS and (1H, 13C) NMR spectra of these complexes and molecular complexes of porphyrins with various acceptors indicated that two lone pairs of the pyrrolenine nitrogens in the tilted porphyrin macrocycle bonded to an iodine(III) center of ICl3.
Capillary Electrophoresis Determination of Berberine in Pharmaceuticals with End‐Column Electrochemiluminescence Detection
Authors: Du Jian‐Xiu , Wang Min
Published: May 2015

Capillary electrophoresis with end‐column electrochemiluminescence (ECL) detection was applied to the determination of berberine, which causes an enhancement of the ECL of tris(2,2‐bipyridyl)ruthenium(II). The assay is accomplished within 4 min with an injection volume of 3.3 nL. The linear analytical range is from 2.0 × 10−8 to 1.0 × 10−6 g mL−1 with a detection limit of 5 × 10−9 g mL−1. The relative standard deviations of the ECL signal and the migration time are 4.4% and 2.7% for 5.0 × 10−7 g mL−1 berberine solution (n = 7). The method was applied to the determination of berberine in tablets and in rhizoma coptidis.
High‐Performance Liquid Chromatography Assay for Moxifloxacin in Bulk, Pharmaceutical Formulations and Serum: Application to In‐Vitro Metal Interactions
Authors: Sultana Najma , Arayne M. Saeed , Akhtar Mahwish , Shamim Sana , Gul Somia , Khan Moona Mehboob
Published: May 2015

A simple reversed phase HPLC method have been successfully developed and validated for the quantitative determination of moxifloxacin (MOX) in bulk material, pharmaceutical formulation and serum. Purospher STAR C18 (25 cm × 4.6 mm, 5 μm) and Discovery C18 (25 cm × 4.6 mm, 5 μm) columns were used. The mobile phase, methanol: acetonitrile: water (85:5:10, v/v/v), pH 2.75 adjusted by phosphoric acid was delivered at a flow rate of 1 mL min−1. The eluents was monitored using UV detector at 290 nm. The proposed method is specific, accurate (99.39‐102.67%), precise (intra‐day variation 0.04‐0.86% and inter‐day variation 0.12‐0.94%) and linearity (R2 > 0.999) within the desired range 0.39‐25 μg mL−1 concentration. The detection and quantification limit was 0.002‐0.51 μg mL−1 and 0.01‐0.555 μg mL−1, respectively. The analysis of variance (ANOVA) and student's t‐test were applied to verify the results. The anticipated method is applicable to routine analysis of MOX in pharmaceutical formulations and human serum samples. It is also applied on interaction of MOX with several essential and trace metals as well as interaction with antacids.
Direct Electron Transfer of Hemoglobin in a Hydrophilic Ionic Liquid/Gellan Gum Composite Film Modified Carbon Ionic Liquid Electrode
Authors: Qiao Li‐Fang , Zheng Jian‐Bin , Gao Rui‐Fang , Sheng Qing‐Lin
Published: May 2015

A gellan gum (GG)‐Hemoglobin (Hb)‐1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate ([BMIM] [BF4])/carbon ionic liquid electrode(CILE), GG‐Hb‐[BMIM][BF4]/CILE, was fabricated, and the direct electron transfer of hemoglobin and electrocatalytic reaction for electrocatalytic abilities were carefully investigated. Scanning electron microscopy images of the modified electrode showed that it had a dendritic structure. UV‐Vis spectra and FT‐IR spectra showed that Hb in the composite film retained its native structure. Cyclic voltammogram of the modified electrode showed that a pair of well‐defined redox peaks of Hb is observed with the formal potential (E0) of −0.278 V (vs. SCE). The electron transfer coefficient (a) and the apparent heterogeneous electron transfer rate constant (ks) was 0.44 and 2.0 s−1, respectively. The modified electrode also exhibited excellent electrocatalytic ability to the reduction of trichloroacetic acid and hydrogen peroxide with a detection limit of 6.8 μmol/L and 1.5 μmol/L (S/N = 3), respectively. The apparent Michaelis‐Menten constant (KMapp) was estimated to be 4.3 mmol/L and 0.13 mmol/L, respectively. The present study proved that the combination of GG‐[BMIM][BF4] film with CILE is able to open up new opportunities for the design of enzymatic biosensors with potential applications in practice.
Asymmetric Synthesis of a New Salen Type‐titanium Complex as the Catalyst for Asymmetric Trimethylsilylcyanation of Aldehydes
Authors: Lin Zheng‐Chang , Chen Chinpiao
Published: May 2015

This work describes the asymmetric synthesis of a new salen‐type ligand via a Diels‐Alder reaction and Curtius rearrangement. The ligand with a norbornane skeleton was used in the trimethylsilylcyanation of aldehydes, but the enantioselectivity was 55%ee. The norborane skeleton was cleaved to destroy this rigidity, and the eanatioselectivity was thereby increased to 85%ee.
Theoretical Study of the Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by β‐Aminothiols and Thioacetates
Authors: Oyaga Sandra Cotes , Valdés José Cotuá , Zambrano Kelly Velásquez
Published: May 2015

The semiempirical PM3 study of the catalytic activity of [(2S)‐1‐benzylpyrrolidinyl]methanethiol 1, S‐([(2S)‐1‐(2,2‐dimethylpropanoyl)pyrrolidinyl]methyl)ethanethioate 2 and [(2S)‐1‐neopentylpyrrolidinyl]methanethiol 3 is described here, also an alternative mechanism for thioacetates type ligands is proposed.
Structural Phase Transition without Accompanied Spin Transition of Complex t‐{Fe(abpt)2[N(CN)2]2}
Authors: Sheu Chou‐Fu , Chuang Yu‐Chun , Liu Yi‐Hung , Sheu Hwo‐Shuenn , Wang Yu
Published: May 2015

A reversible crystal‐to‐crystal structural phase transition is found in one of the polymorphs (A) of complex t‐{Fe(abpt)2[N(CN)2]2} (abpt = 4‐Amino‐3,5‐bis (pyridin‐2‐yl)‐1,2,4‐triazole). The crystal at 25 K remains unchanged as triclinic space group P−1 from that of the ambient temperature, but with different cell parameters: a = 8.7960(6), b = 8.8110(9), c = 10.1020(7) Å, α = 94.146(8)°, β = 93.296(6)°, γ = 114.460(7)°, V = 707.48(10) Å3. Thermal‐dependent powder X ‐ray diffraction reveals a first order phase transition with transition temperature, T1/2, at 270 K, which coincides with the change in cell parameters monitored by single crystal diffraction experiment. The molecular structure does vary on the orientation of the axial ligand, N(CN)2, during the phase transition, however the Fe‐N bond distance and the octahedron distortion parameters around Fe indicate that Fe remains at high spin state even after the phase transition which is in accord with the observed thermal‐dependent magnetic measurement.
2‐Amino‐3‐naphthylacrylonitrile Derivatives as Green Luminance Dyes
Authors: Lin Richard , Horng Haw‐Chiung , Lin Hsiu‐Mei , Lin Si‐Yu , Hon Yung‐Son , Chow Tashin J.
Published: May 2015

Three derivatives of 2‐amino‐3‐naphthylacrylonitrile 2∼4 were synthesized as potential green luminance dyes. The green emission is derived from a charge transfer transition, which exhibits an apparent solvatochromic effect. The crystal structures of derivatives 2 and 3 were resolved by X‐ray diffraction analyses. The diphenylamino derivative 2 was found in monoclinic P21/n space group with a = 10.032(2), b = 17.034(5), c = 12.143(6), and β = 112.02(3)°. The carbazyl derivative 3 was found in triclinic P‐1 space group with a = 8.890(3), b = 9.296(6), c = 12.209(5), and α = 98.89(4)°, β = 93.46(3)°, γ = 116.47(4)°. The amino group in 2 forms a better resonance with acrylonitrile group than that in 3. The electronic nature of the amino group is responsible for the spectral difference among three compounds. The effect is verified by ab initio molecular modeling.
Anion and Length‐Modulated Bidentate N‐Donor Ligand Controlled Zn(II) Metal‐Organic Frameworks
Authors: Luo Shih‐Ci , Lin Ivan J. B.
Published: May 2015

Two metal complexes [Zn2(BTE)2Cl4](1a) and [Zn(BTEE)Cl2](1b) and two coordination polymers [Zn(BTE)2(NO3)2]n (2) and {[Zn(BTE)2(H2O)2](ClO4)2·2H2O}n (3·2H2O, abbreviated in 3) constructed from two structurally related ligands, 2,2′‐bis(1H‐1,2,4‐triazolyl)ether (BTE) and 2,2′‐bis(1H‐1,2,4‐triazolyl)ethoxyethane (BTEE) have been synthesized. Complexes 1a and 1b display zero‐dimension macrocyclic ring structures, while coordination polymers 2 and 3 exhibit one‐dimension chain and two‐dimension corrugated sheet, respectively. Then, intermolecular hydrogen bonding interactions in 1–3 expand those lower dimension structures to extended frameworks.
A New Self‐Polymerization of Acrylic Acid with a Mono‐Aziridine Containing Compound
Authors: Chen Po‐Cheng , Wang Shih‐Chieh , Hwang Jing‐Zhong , Yeh Jen‐Taut , Huang Chi‐Yuan , Chen Kan‐Nan
Published: May 2015

A new self‐polymerization took place between acrylic acid (AA) and a mono‐aziridine containing compound, e.g. methyl 3‐(aziridin‐1‐yl) propanoate (MAP) upon mixing that resulted in formation of a linear polyethyleneimine (PEI) with amino‐ester bonds. This self‐polymerization has a key reaction of ring opening reaction occurred between carboxylic acid and aziridine that led to an amino‐ester bond formation. The model reactions of trimethylacetic acid (TMAA) with MAP and then with ethyl acrylate (EA) were designed to demonstrat the self‐polymerization mechanism. The model reaction product at each stage related to that of polymerization was characterized by FT‐IR and FT‐NMR. The self‐polymerization occurred via three consecutive reactions at ambient temperature, which were acid‐base neutralization, aziridine ring‐opening and finally Michael addition reaction. Their average molecular weight of resulting PEI could be over 60,000 in aqueous medium or a higher polymer formation in bulk, which is insoluble in water or any organic solvent. This self‐polymerization process could have potential for adhesives, composite materials or other polymer applications.
Synthesis of Nanocrystalline SrFe12O19 Particles Doped with SrTiO3 via Combustion Synthesis for Microwave Absorption Applications
Authors: Chang Ching‐Chih , Chen Yi‐Chuan , Wang Gaw‐Pying , Hwang Chyi‐Ching , Yeh Cyuan‐Cing
Published: May 2015

Nanocrystalline hard magnetic SrFe12O19 (Sr‐M) particles incorporated with high dielectric constant SrTiO3 (STO, up to 15 mol%), which are being investigated as potential materials for microwave absorption, were synthesized simultaneously in one step through a combustion reaction using nitrates and glycine as raw materials. The desired products simply composed of Sr‐M and STO can be obtained after calcination of the as‐burned nanoparticles products at 900 °C for 1 h. The effects of the STO content on the relative complex permittivity (ϵr = ϵ′ −jϵ″), permeability (μr = μ′ −jμ″) and the behavior of microwave absorption in the frequency range of 1 MHz − 1.8 GHz have been investigated. Adding more STO to Sr‐M was demonstrated not only to improve ϵr but also to modify μr. In addition, it was found that the sintered specimens showed a characteristic of broad‐band absorption, and their absorbing efficiencies were enhanced with increasing STO content.
A Prefractionation Method Can Separate Proteomic Proteins into Multigroups by One‐step Extraction
Authors: Bai Hai‐Xin , Liu Xiao‐Hua , Yang Fan , Yang Xiu‐Rong , Wang Er‐Kang
Published: May 2015

A variety of prefractionation methods for proteome analysis had been developed, but some of these had defects such as requirements sophisticated apparatus, expensive reagents, too long experimental time or complicated operation. In this work, a simple, rapid and low‐cost prefractionation method for proteome analysis was developed based on an aqueous two‐phase system (ATPS), which used simple and inexpensive components in place of the polymers, could pre‐separate proteomic proteins into multigroups by one‐step extraction according proteins' difference in solubility. The ATPS consisted of isopropanol, ammonium sulfate and water. The highlight attractiveness of this method included simplicity, rapidity, low cost and the ability of concentrating target proteins. Attractiveness of this method also included biocompability, amenability to linear scale‐up, potential for continuous operation, and being easy or no need for separating the target proteins from phase‐forming reagents before gel electrophoresis analysis. It was the first time that the ATPS composed of isopropanol, ammonium sulfate and water was used in studying the prefractionation method for proteome analysis. Thus, this method had great significance in proteome analysis and methodology.
Study on the Determination of Trace Zinc by Spectrophotometry after Flotation Separation with Ternary Association Complex System
Authors: Tu Chang‐Qing , Wen Xin‐Rong
Published: May 2015

The paper presents a novel method for the flotation separation of Zn2+ with ternary association complex system prior to the determination by spectrophotometry. The effects of different parameters, such as the dosages of NH4SCN and dodecyl trimethyl ammonium chloride (DTAC), various salts and acidity etc. on the flotation yield of Zn2+ have been investigated to select the experimental conditions. The possible flotation mechanism of Zn2+ was discussed. The results showed that by controlling pH 4.0, in the presence of 1.0 g NaBr, when the dosage of 0.1 molṁL−1 NH4SCN solution was 2.50 mL and 5.0 × 10−3 molṁL−1 DTAC solution was 2.00 mL respectively, the water‐insoluble ternary association complex of [Zn(SCN)4] (DTAC)2 which produced by Zn2+ and SCN−, DTAC cation (DTAC+) floated above water phase and liquid‐solid phases were formed with clear interface, while K+, Na+, Ca2+, Mg2+, Al3+, Fe2+, Mn2+, Cd2+, Co2+ and Ni2+ could not be floated, so Zn2+ was floated quantitatively at pH 4.0. Thereby, the quantitative separation of Zn2+ from the above metal ions could be achieved. A new method of determination of trace zinc by flotation separation was established. The proposed method has been successfully applied to the determination of Zn2+ in plating waster water, and the results agreed well with AAS method. The recoveries were 93.6%∼106.4%, and the RSD was 1.8%∼2.3%.
Isolation and Purification of Flavonoids from Ziziphus jujuba by High‐Speed Counter‐Current Chromatography
Authors: Bai He‐Long , Wang Jing , Liu Chun‐Ming , Li Li
Published: May 2015

High‐Speed Counter‐Current Chromatography (HSCCC) coupled with Diode array detector (DAD) was successfully applied to the isolation and purification of three flavonoids from Ziziphus jujuba. The solvent system was composed of ethyl acetate‐n‐butanol‐water (3:2:5, v/v/v). The purity of compounds 1, 2 and 3 was above 90.0% by HPLC‐DAD and the structures of these compounds were identified by electrospray ionization tandem mass spectrometry (ESI‐MSn) as spinosin, 6′″‐sinapoylspinosin, 6′″‐feruloylspinosin.
Metal Acetate Mediated Biginelli One‐Pot Synthesis
Authors: Karamat A. , Khan M. A. , Sharif A.
Published: May 2015

A one‐pot and efficient synthesis of Biginelli compounds mediated by metal acetates is described. It was found that metal acetates are effective promoters of Biginelli reaction.
Synthesis of Capped Tetrachelate Porphyrins: Towards “Insulation” of the Chromophore on Semiconductor Surfaces
Authors: Lee Chi‐Hang , Chitre Keyur , Galoppini Elena
Published: May 2015

A novel “capped” metal‐free tetraphenylporphyrin 1, was synthesized and characterized. The cap was designed to “insulate” the chromophoric unit and prevent aggregation as well as undesired contacts on the semiconductor surface. The cap was made of a benzene unit linked by four methylenic units (‐(CH2)4−) to the meso‐phenyl ring of the porphyrin core through an ether group. The COOMe groups are in meta position for an ideal bite angle to the semiconductor surface and the constrain imposed by the cap avoids conformational freedom of the anchoring groups. The 1H NMR spectrum of 1 suggests that the metal free macrocycle 1 is distorted from planarity. The solution UV‐Vis and fluorescence emission spectra of 1 were typical of a metal‐free tetraphenylporphyrin.
Preparation and Photovoltaic Characterization of Free‐Base and Metallo Carboxyphenylethynyl Porphyrins for Dye‐Sensitized Solar Cells
Authors: Lin Ching‐Yao , Lo Chen‐Fu , Hsieh Min‐Hsu , Hsu Shun‐Ju , Lu Hsueh‐Pei , Diau Eric Wei‐Guang
Published: May 2015

Free‐base, manganese, iron, cobalt, nickel, copper and zinc 5‐(4‐carboxy‐phenylethynyl)‐10,20‐biphenylporphines are synthesized to study the impact of central metal ions to the photovoltaic performance of the solar cells.
3D Electrodes for Dye‐Sensitized Solar Cells: Synthesis of ITO Nanowire Arrays Inside the TiO2 Nanotubes
Authors: Hung Pei‐Ling , Wen Ming‐Hsien , Hung Kai‐Hsiang , Bow Jong‐Shing , Wang Hong‐Wen , Han Jeff C. C. , Lu Yung‐Fang , Chung Jen‐Chieh , Liu Yu‐Chang , Zeng Yu‐Zhen , Ratinac Kyle R.
Published: May 2015

In the present study, ITO nanowires electrode within the anodized TiO2 nanotubes without using the polycarbonate membrane templates were attempted. The process begins with an anodized TiO2 nanotube arrays (TNA) and subsequent growth of indium‐tin‐oxide (ITO) nanowires into the TiO2 nanotube arrays via the electrophoretic process (EPD). The open‐end of TiO2 nanotubes were synthesized for the photoelectrode of DSSC. ITO nanowires were then grown into these TNA by EPD process. The composite of ITO/anodized TNA was employed as the working electrode for the assembly into DSSCs. The advantage of the present method is that the membrane templates in EPD process were not required. In addition, the ITO nanowires will surely not contact each other which might cause short circuit. The morphologies and the structures of ITO nanowires and TNA electrode were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
Modeling of the J‐V Characteristics for ITO/CuPc/C60/Al Hetero‐Structure Solar Cells
Authors: Wei Shi‐Zhan , Lin Chih‐Chung Chang, Ru‐Hau , Lin Ku‐Yen , Jong Ming‐Nan , Juey Liu‐Ting , Chiu Kuan‐Cheng
Published: May 2015

The characteristics of current density (J) versus bias voltage (V) for various organic photovoltaic cells (OPVCs) with a basic hetero‐structure of ITO/CuPc/C60/Al are measured and analyzed by an equivalent circuit model. Two modeling schemes are developed and analyzed. The first one involves the direct fit of the J‐V data to the equation governed by the equivalent circuit. But for some of the J‐V data, the direct‐fit scheme occasionally leads to unrealistic fitting values. To maximize the usefulness of the equivalent circuit, a second modified scheme is then proposed and justified. Finally, together with experimental J‐V data and numerical fitting results, effects from the adding of C60 hetero‐junction layer and from the changing of substrate temperature during the deposition of CuPc layer are discussed for various OPVCs.
Wave‐Like Energy Resonance Transfer of Plasmonic Absorption Gap in Plasmon‐Sensitized Solar Cell, Plasmonic Solar Cells, and Plasmonic Photovoltaics
Authors: Su Yen‐Hsun , Tu Sheng‐Lung , Su Yi‐Hui , Chang Shih‐Hui
Published: May 2015

Oscillators in classical electromagnetic refer to electrons transition between energy band gaps in visible light in quantum mechanism. In experimental section, Fermi‐level of bulk‐like gold NPs contacts that of semiconductor due to the balance of the electronic density on the surface. Energy level, E, referred by the expectation value of the SPR dipole is below the work function of gold NP. The different energy between E and work function is Eg. In theory, SPR of gold NP acts as an energy level to transfer energy via wave‐like oscillator. Photoelectrons inject into the surrounding semiconductor and are difficult to come back due to the Schottky barrier. Furthermore, photoelectric current of dye/Au NPs/P‐25 TiO2 on the ITO glass substrate indicates that optical current is about −0.5 μA, which results from the higher level of the surface plasmon of Au NPs than that of N3 dye and TiO2.
Simultaneous Determination of Prazosin, Atorvastatin, Rosuvastatin and Simvastatin in API, Dosage Formulations and Human Serum by RP‐HPLC
Authors: Sultana Najma , Arayne M. Saeed , Shah Shabana Naz , Shafi Nighat , Naveed Safila
Published: May 2015

Prazosin hydrochloride is the first developed selective antagonist for α1 — adrenoceptors, which is used as antihypertensive agent. Statins are used in the treatment of various types of hypercholesterolemia. In the present paper a simple, specific an accurate RP‐HPLC method was developed and validated for the simultaneous determination of prazosin, atorvastatin, rosuvastatin and simvastatin in active and in dosage formulations. A nucleosil 100‐10, C‐18, 10μ column having 250 × 4.6 mm i.d. in isocratic mode, with mobile phase containing methanol:water:acetonitrile (70:20:10) adjusted to pH 2.5 ± 0.02 using orthophosphoric acid. The flow rate was 1 mLmin−1 and effluents were monitored at 240 nm. The % recovery for all the drugs in formulations was found to be 94‐105%. The parameters such as accuracy (%RSD less than 2), precision (%RSD less than 2), linearity (>0.999) were found to be satisfactory. The presented method was applied without any interference of excepients for the determination of tablets. The proposed method due to its low LOQ, excellent accuracy, precision and selectivity could be used for routine quality control.
DNA Binding Studies and Cytotoxicity of Ethylenediamine 8‐Hydroxyquinolinato Palladium(II) Chloride
Authors: Mansouri‐Torshizi H. , Saeidifar M. , Rezaei‐Behbehani G. R. , Divsalar A. , Saboury A. A.
Published: May 2015

Interaction between ethylenediamine 8‐hydroxyquinolinato palladium(II) chloride and calf thymus DNA (CT‐DNA) in aqueous solution were studied by UV‐Visible absorption, fluorescence spectroscopic techniques and gel chromatography at temperatures of 300 K and 310 K. The complex bound strongly and intercalatively to the CT‐DNA. The results of the cytotoxicity assay of the Pd(II) complex on the leukemia cell line, K562 indicated lower cytotoxicity than cisplatin. The Pd(II) complex is considered an agent with potential antitumor activity. The calculation of several binding and thermodynamic parameters of the inclusion Pd(II) complex with CT‐DNA may provide deeper insights into the mechanism of action of these types of complexes with nucleic acids.
Method of stimulus combination impacts resistance to extinction
Authors: Podlesnik Christopher A. , Bai John Y. H.
Published: May 2015

Reinforcing an alternative response in the presence of the stimuli governing a target response increases resistance to extinction of target responding, relative to training target responding on its own. Conversely, training alternative and target responses in the presence of different stimuli and combining those stimuli only decreases resistance to extinction of target responding, relative to target responding on its own. The present study assessed how different methods of combining discriminative stimuli influence resistance to extinction of responding in pigeons. As in previous studies, combining stimuli across different keys only decreased resistance to extinction of target responding relative to target responding on its own. In comparison, combining stimuli on the same key initially increased resistance to extinction of target responding, but repeated tests resulted in similar levels of responding as target responding with stimuli combined on separate keys. Moreover, greater overall reinforcement rates produced greater resistance to extinction with both methods of combining stimuli, consistent with behavioral momentum theory. These findings reveal several behavioral processes influence the outcome of combining stimuli—including perceptual processes, discriminative control by contingencies, response competition, and behavioral momentum.
The role of chairman and research director in influencing scholarly productivity and research funding in academic orthopaedic surgery
Authors: Stavrakis Alexandra I. , Patel Ankur D. , Burke Zachary D. C. , Loftin Amanda H. , Dworsky Erik M. , Silva Mauricio , Bernthal Nicholas M.
Published: May 2015

The purpose of this study was to determine what orthopaedic surgery department leadership characteristics are most closely correlated with securing NIH funding and increasing scholarly productivity. Scopus database was used to identify number of publications/h‐index for 4,328 faculty, department chairs (DC), and research directors (RD), listed on departmental websites from 138 academic orthopaedic departments in the United States. NIH funding data was obtained for the 2013 fiscal year. While all programs had a DC, only 46% had a RD. Of $54,925,833 in NIH funding allocated to orthopaedic surgery faculty in 2013, 3% of faculty and 31% of departments were funded. 16% of funded institutions had a funded DC whereas 65% had a funded RD. Department productivity and funding were highly correlated to leadership productivity and funding(p< 0.05). Mean funding was $1,700,000 for departments with a NIH‐funded RD, $104,000 for departments with an unfunded RD, and $72,000 for departments with no RD. These findings suggest that orthopaedic department academic success is directly associated with scholarly productivity and funding of both DC and RD. The findings further highlight the correlation between a funded RD and a well‐funded department. This does not hold for an unfunded RD. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1407–1411, 2015.