bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectrofluorimetric Determination of Itraconazole in Dosage Forms and Spiked Human Plasma
Authors: El‐Enany N. , El‐Sherbiny D. , Belala F. 
Published: May 2015

AbstractA highly sensitive fluorimetric method was developed for the determination of itraconazole in pharmaceutical preparations and biological fluids. The proposed method is based on measuring the native fluorescence intensity of itraconazole in methanol at 380 nm after excitation at 260 nm. The fluorescence intensity‐concentration plot was rectilinear over the range 0.2 to 2.0 μg/mL with a lower detection limit of 0.05 μg/mL (6.52 × 10−11 M). The method was further applied to the determination of itraconazole in capsules and spiked human plasma, the mean % recoveries (n = 4) was 100.37 ± 0.86 and 95.47 ± 2.93, respectively. The mean % recoveries were in agreement with those obtained from a reference method.
Multi‐Channel Surface Acoustic Wave (SAW) Sensor Based on Artificial Back Propagation Neural (BPN) Network and Multivariate Linear Regression Analysis (MLR) for Organic Vapors
Authors: Hsu Hui‐Ping , Shih Jeng‐Shong 
Published: May 2015

AbstractA six‐channel surface acoustic wave (SAW) detection system with a 315 MHz one‐port quartz resonator and a homemade computer interface for signal acquisition and data processing was developed to detect various organic vapors. The oscillating frequency of the SAW quartz crystal decreased due to the adsorption of organic molecules on the coating materials. Polyethylene glycol, 18 crown 6 (18C6), Cr3+/cryptand‐22, stearic acid, polyvinylpyrrolidene and triphenyl phosphine coated quartz crystals were used as sensors. An artificial back propagation neural (BPN) network was used to recognize various organic gases such as hexane, 1‐hexene, 1‐hexyne, 1‐propanol, propionaldehyde, propionic acid and 1‐propylamine. It showed not only the distinction of unity of organic vapors but also mixtures of gases. The learning rate and the hidden unit of a neural network system for BPN analysis were investigated. Furthermore, the concentrations of these organic vapors were computed with about 10% error by multivariate linear regression analysis (MLR). MLR analysis with a multichannel SAW sensor was applied to determine the concentration of each component in a mixture of 1‐hexene, 1‐hexyne and propionaldehyde.
The Efficiency of a Microcolumn of Rice Bran for On‐line Trace Enrichment in FI‐AAS, a Highly Selective System for On‐line Preconcentration and Determination of Copper
Authors: Dadfarnia S. , Haji Shabani A. M. , Gohari M. 
Published: May 2015

AbstractA flow injection flame atomic absorption spectrometry system incorporating a microcolumn of rice bran was designed, and its capability for on‐line trace enrichment of copper, cadmium and lead was studied. Analytes were deposited on the microcolumn by processing a standard or solution of analytes on the column. Injection of 250 μL of nitric acid (1 mol/L) then served to elute the retained species to FAAS. The procedure was successfully applied for determination of copper in tap water, well water and multivitamin tablets. The accuracy was assessed through recovery experiments and independent analysis by furnace‐AAS. A sample volume of 20 mL of copper resulted in a preconcentration factor of 96; precision value at the 20 μg/L was 4.1%.
Chemical Constituents from the Roots of Patrinia Rupestris
Authors: Yang Xiu‐Ping , Yuan Cheng‐Shan , Jia Zhong‐Jian 
Published: May 2015

AbstractPhytochemical investigation of the roots of Patrinia rupestris afforded a new triterpenoid patrirupin A (1) and a new iridoid patrirupin B (2), as well as three known triterpenoids: 3‐oxo‐olean‐12‐en‐28‐oic acid (3), ursolic acid (4), α‐amyrin (5), three known iridoids: isovaltratum (6), 11‐ethoxyviburtinal (7), homobaldrinal (8), five known steroids: ergosterol (9), ergost‐6,22‐diene‐3β,5α,8α‐triol (10), 6‐hydroxenone (11), β‐sitosterol (12), daucosterol (13), and two known flavones: 1‐hydroxy‐5‐methoxy xanthen‐9‐one (14), 3′,4′,5,7‐tetrahydroxyflavanone (15). The new compounds were characterized by means of spectroscopic methods including UV, IR, 1D, 2D NMR and HRESIMS, and the known ones were established on the basis of comparing their NMR data with those of the corresponding compounds in the literature.
Chemical Constituents from the Leaves of Litsea Acutivena
Authors: Tsai Ian‐Lih , Cheng Ming‐Jen , Hung Hsiu‐Wen , Cheng Hsin‐I , Chen Ih‐Sheng 
Published: May 2015

AbstractContinuous investigation of the CHCl3‐soluble and n‐hexane fractions of the leaves of Litsea acutivena Hayata (Lauraceae) led to the isolation of one new butanolide, acutilactone (1), one new lactone, 4‐nonacosyl‐dihydrofuran‐2‐one (2), together with 15 known compounds. The known compounds included one butanolide, one norisoprenoid, one quinone, two steroids, one triterpenoid, one coumarin, two fatty acids, one amide, and five other compounds. The structures of these compounds were determined by means of spectral analyses.
A Facile Method for Synthesis of 5‐Hydroxypentene via Sonochemical Barbier Reaction
Authors: Lee Adam Shih‐Yuan , Tsao Kuo‐Wei , Chang Yu‐Ting , Chu Shu‐Fang 
Published: May 2015

AbstractA series of 5‐hydroxypentenes was synthesized from the reaction mixture of Mg powder, 1,2‐dibromoethane, 4‐bromobutene and aldehydes in THF under ultrasound. This sonochemical Barbier reaction provides a simple and alternative method for preparation of 5‐hydroxypentene instead of the allylating reagent with epoxide.
Investigation of the Interaction between N,N′‐Di(4‐Chlorophenyl)Thiourea and Human Serum Albumin by Fluorescence Spectroscopy: Synchronous Fluorescence Determination of Human Serum Albumin
Authors: Cui Feng‐Ling , Wang Jun‐Li , Cui Yan‐Rui , Li Jian‐Ping 
Published: May 2015

AbstractUnder physiological conditions, interaction between N,N′‐di(4‐chlorophenyl)thiourea synthesized and human serum albumin was investigated by using fluorescence spectroscopy and UV absorption spectrum. The intrinsic fluorescence of human serum albumin was quenched by N,N′‐di(4‐chlorophenyl)‐thiourea through a static quenching procedure. The binding constants (K) at 14 °C and 24 °C were obtained, and the values were 2.541 × 105 M−1 and 2.021 × 105 M−1, respectively. Thermodynamic parameter enthalpy change (ΔH) and entropy change (ΔS) were calculated to be ‐16.19 KJ/mol and 47.05 J·mol1·K−1, respectively, which indicated that hydrophobic force played a major role in interaction. The binding distance was evaluated on the basis of the theory of Föster energy transfer. The effects of various metal ions on the binding constants of N,N′‐di(4‐chlorophenyl)thiourea with human serum albumin were studied. A synchronous fluorescence technique for determination of human serum albumin was developed, and the method was successfully applied to the detection of HSA in human serum samples.
Liquid‐Phase Synthesis of 2‐Methyl‐2‐Aryloxypropanoic Acid Derivatives from Polyethylene Glycol) Supported 2‐Bromo‐2‐Methylpropanoate
Authors: Huang Bin , Huang Pei‐Gang , Sheng Shou‐Ri , Wang Qiu‐Ying , Guo Lei , Jiang Shao‐Hua 
Published: May 2015

AbstractAn efficient liquid‐phase synthesis of 2‐methyl‐2‐aryloxypropanoic acid derivatives with good yields and high purity on soluble polyethylene glycol (PEG) has been developed by treatment of PEG‐bound 2‐bromo‐2‐methylpropanoate with phenoxides in the presence of a catalytic amount of NBu4I and KI, and subsequent cleavage from the PEG.
Brilliant Blue R Adsorption from Aqueous Solution on Activated Carbon Produced from Corncob Waste
Authors: Bangash Fazlullah Khan , Alam Sultan 
Published: May 2015

AbstractBrilliant blue R adsorption from aqueous solution on activated carbon produced from corncob waste was investigated. The carbon samples were characterized by XRD, SEM, EDS and FTIR methods. The surface functional groups (carboxyl, lactone or phenol, ether, hydroxyl) disappeared at high activation temperature, resulting in a high amount of carbon with respect to oxygen. The kinetic studies of the adsorption of brilliant blue R on carbon at 10 and 45 °C showed that the first order and intraparticle diffusion models apply to the data. The reaction rate increased with the increase in temperature of adsorption/activation. Thermodynamic parameters like ΔE#, ΔH# and ΔS# for adsorption were calculated from the kinetic data. The positive value of ΔH# shows the endothermic nature of adsorption which decreased with the increase in adsorption/activation temperature. The negative values of ΔS# reflect a decrease in the disorder of the system at the solid‐solution interface during adsorption. Equilibrium studies showed that the data fits the Langmuir model.
Concise Synthesis and Antimicrobial Activities of New Substituted 5‐Isoxazolpenicillins
Authors: Wang Xi‐Zhao , Jia Jiong , Zhang Yan , Xu Wei‐Ren , Liu Wei , Shi Fang‐Niu , Wang Jian‐Wu 
Published: May 2015

AbstractThe synthesis of a series of new 5‐isoxazolpenicillins is described, which were obtained by coupling substituted isoxazoles with 6‐APA. Concise large‐scale synthesis of 3,5‐disubstituted isoxazoles by 1,3‐dipolar cycloaddition using copper(I) as catalyst was also investigated. Representative compounds were assayed for antimicrobial activities, showing satisfactory antimicrobial activities against Gram‐negative bacteria.
Cyclic Voltammograms of Ferrocene on Multi‐Walled Carbon Nanotubes (MWCNTs)‐Modified Edge Plane Pyrolytic Graphite (EPPG) Electrode in Room Temperature Ionic Liquids (RTILs) of 1‐Ethyl‐3‐Methylimidazolium Tetrafluoroborate (EMIBF4)
Authors: Ding Ke‐Qiang , Wang Qing‐Fei , Zhao Mian 
Published: May 2015

AbstractIn this work, the electrochemical behavior of ferrocene (Fc) was investigated by cyclic voltammetry (CV) in room temperature ionic liquids (RTILs) of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF4) on glass carbon (GC), edge plane pyrolytic graphite (EPPG) and multi‐walled carbon nanotube (MWCNTs)‐modified EPPG electrodes, respectively. The results demonstrated that on GC electrode, pairs of well‐defined reversible peaks were observed, while for the electrode of EPPG, the peak potential separation (ΔEp) is obviously larger than the theoretical value of 59 mV, hinting that the electrode of EPPG is distinguished from the commonly used electrode, consistent with the previous proposition that EPPG has many “defects”. To obtain an improved electrochemical response, multi‐walled carbon nanotubes (MWCNTs) were modified on the electrode of EPPG; the increased peak current and promoted peak potential separation not only proved the existence of “defects” in MWCNTs, but also supported that “creating active points” on an electrode is the main contribution of MWCNTs. Initiating the electrochemical research of Fc on the MWCNTs‐modified EPPG electrode in RTILs and verifying the presence of “defects” on both EPPG and MWCNTs using cyclic voltammograms (CVs) of Fc obtained in RTILs of EMIBF4, is the main contribution of this preliminary work.
Estimation of Residual Nickel and Some Heavy Metals in Vanaspati Ghee
Authors: Khan Hizbullah , Fida Mohammad , Mohammadzai Imdad Ullah , Khan Mumtaz 
Published: May 2015

AbstractTo convert vegetable edible oils into vanaspati ghee, nickel is used as a catalyst in the hydrogenation process. A simple and fast method for the trace level determination of nickel in ghee is reported. In this work different methods were applied for the extraction of residual nickel from ghee samples. Using toluene, benzene and carbon tetrachloride as organic solvents, an acid mixture was used for the extraction of nickel. Extracted nickel was quantified with atomic absorption and colorimetric methods. Among the organic solvents, toluene proved to be the best solvent mediating a 95% extraction of nickel from ghee samples. Nickel was extracted and determined in ten different brands of ghee and in all samples its amount was well above the permissible limit of WHO (0.2 μg/g). Other metals like lead, zinc, copper, and cadmium were also determined and their concentrations were found to be much below the WHO permissible limits.
ZrCl4 as an Efficient Catalyst for Crossed‐Aldol Condensation of Cyclic Ketones with Aromatic Aldehydes in Refluxing Ethanol
Authors: Khodaei Mohammad Mehdi , Bahrami Kiumars , Khedri Mohammad 
Published: May 2015

AbstractThe aldol condensation reaction of cyclic ketones with aromatic aldehydes in ethanol under reflux conditions using ZrCl4 as a catalyst to afford the corresponding α,α′‐bis(substituted benzylidene and cinnamylidene)cycloalkanones in excellent yields has been described. No self‐condensation product was produced.
Semiempirical Molecular Orbital Studies of the Acylation Step in the Lipase‐Catalyzed Ester Hydrolysis
Authors: Zhao Jian‐Hua , Liu Hsuan‐Liang , Lin Hsin‐Yi , Huang Chih‐Hung , Fang Hsu‐Wei , Tsai Shau‐Wei 
Published: May 2015

AbstractIn this study, we present the results from the semiempirical molecular orbital calculations for the acylation step in the lipase‐catalyzed ester hydrolysis. The results reveal that the lowest energy path for the formation of the tetrahedral intermediate is for the serine residue of the catalytic triad to attack the substrate, followed by coupling heavy atom movement and proton transfer. The calculations of four active site models show that the cooperation of the aspartate group and the oxyanion hole is capable of lowering the activation energy by about 16 kcalmol−1. Our results further suggest that the lipase‐catalyzed ester hydrolysis adopts the single proton transfer mechanism.
The Effect of Substituents on the Fluorescent Properties of Para‐Phenylenevinylene
Authors: Ding Liang , Ding Yu‐Qi , Teng Qi‐Wen , Wang Ke 
Published: May 2015

AbstractSemi‐empirical AM1 method and density function theory were used to study the electronic structures and spectroscopic characteristics of the luminescent material analogous to PPV (para‐phenylenevinylene) oligomers attached to different substituents. It was indicated that the LUMO‐HOMO energy gaps were changed distinctly by means of the electron‐donating effect, conjugated effect and steric effect. The fluorescent wavelength in the fluorescent spectrum, the main absorption peaks in the electronic spectra and the chief bands in the IR spectra for the complexes were red‐shifted, relative to those of the parent molecule, owing to the extension of the conjugated system, the shrink of the energy gap and the weakening of the C=C bonds, respectively. The 13C chemical shifts were also moved obviously when the substituents on the matrix were changed.
An Efficient Method for the Enamination of 1,3‐Dicarbonyl Compounds with Ceric Ammonium Nitrate (CAN)
Authors: Mo Li‐Ping , Liu Shu‐Fen , Li Wan‐Zhi 
Published: May 2015

AbstractAn efficient method for the enamination of 1,3‐dicarbonyl compounds by employing ceric ammonium nitrate (CAN) as the catalyst has been described. A variety of β‐amino‐α,β‐unsaturated ketones and esters have been synthesized in excellent yield within a short reaction time under solvent‐free conditions.
Highly Efficient and Selective Membrane Transport of Silver(I) Using Dibenzodiaza‐15‐Crown‐4 as a Selective Ion Carrier
Authors: Shamsipur Mojtaba , Kazemi Sayed Yhaya 
Published: May 2015

AbstractA chloroform membrane system containing dibenzodiaza‐15‐crown‐4 was found to be a highly efficient and selective transport of Ag+ ions through a chloroform liquid membrane. In the presence of thiosulfate ion as a suitable ion stripping agent in the receiving phase, the amount of silver transported across the liquid membrane after 105 minis 95 ± 1.3%. The selectivity of Ag+transport from aqueous solutions containing Tl+, Pb2+, Cd2+, Ni2+, Co2+, K+, Ca2+, Sr2+, Hg2+, Zn2+, Cu2+was investigated. The interfering effect of Cu2+ ions was drastically diminished in the presence of EDTA as a proper masking agent in the source phase.
Synthesis and Biological Activity of Mercaptobenzoxazole Based Thiazolidinones and Their Arylidenes
Authors: Kohli P. , Srivastava S. D. , Srivastava S. K. 
Published: May 2015

AbstractArylidenes of thiazolidines with mercaptobenzoxazole, namely[(aryl‐4‐oxo‐1,3‐thiazolidin)‐hydrazinoacetyl‐mercaptobenxazole]; (5‐arylidene)‐2‐aryl‐4‐oxo‐1,3‐thiazoliden hydrazinoacetyl‐mercaptobenxazole were synthesized. Their chemical structures have been confirmed by 1H NMR, IR, mass spectra and also by microanalytical data. Antimicrobial evaluation was done by agar dilution method against three pathogenic bacteria viz. Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae and three pathogenic fungi viz. Aspergillus niger, Candida albicans and Fusarium oxysporum. Among new derivatives evaluated, the chloro derivatives exhibited higher potency as compared to the standard drugs streptomycin (for bacteria) and griseofulvin (for fungi) against the tested organisms.
A Clean Synthesis of 1,4‐Diarylquinoline Derivatives Catalyzed by TEBAC in Aqueous Media
Authors: Wang Xiang‐Shan , Zhang Mei‐Mei , Jiang Hong , Shi Da‐Qing , Tu Shu‐Jiang 
Published: May 2015

AbstractA series of 1,4‐diarylquinoline derivatives were synthesized by the reaction of arylmethylidenemalononitriles or 2‐cyano‐3‐aryl‐1‐acrylate and 3‐arylamino‐5,5‐dimethylcyclohex‐2‐enone in aqueous media at 100 °C catalyzed by TEBAC. Meanwhile, the water medium was chosen as green solvent.
Synthesis of Thiophenes, Azoles and Azines with Potential Biological Activity by Employing the Versatile Heterocyclic Precursor N‐Benzoycyanoacetylhydrazine
Authors: Mohareb Rafat M. , Ho Jonathan Z. , Alfarouk Fatma O. 
Published: May 2015

AbstractThis research work is concerned with the use of N‐benzoyl cyanoacetylhydrazine (3) in synthesizing several new heterocyclic compounds with potential biological activity, via its reaction with various chemical reagents. The synthesized derivatives have actually exhibited, upon screening, antibacterial and antifungal activities.
Spectrophotometric Determination of Acidity Constants of 4‐(2‐Pyridylazo) Resorcinol in Various Micellar Media Solutions
Authors: Ghasemi Jahanbakhsh , Peyman Hossein , Niazi Ali 
Published: May 2015

AbstractDissociation equilibria of 4‐(2‐pyridylazo) resorcinol (PAR) in aqueous micellar solutions were determined spectrophotometrically at 25 °C and at the constant ionic strength I = 0.1 M KNO3. For this purpose, the effect of nonionic (Brij‐35, Triton X‐100, Triton X‐114, Triton X‐405), and anionic (SDS) surfactants on the absorption spectra of PAR at different pH values was studied. Results show that the pKa values and pure spectra of each species of PAR are influenced by percentages of a neutral and an anionic surfactant such as Brij‐35, Triton X‐100, Triton X‐114, Triton X‐405 and SDS, respectively, added to the solution of this reagent.
Synthesis, Properties, and Evolution Mechanism of Morphology Tunable InPO4 Crystals
Authors: Lin Xin‐Hong , Wang Ya‐Chen , Su Yu‐Han , Yang Chung‐Sung 
Published: May 2015

AbstractIn the synthesis of InPO4 crystals, using F127 [(EO)106(PO)70(EO)106] as a structure‐directing template, a morphology tunable progress was observed during the crystal evolution. By verifying the initial pH from 1.0 to 12.0, the morphology is evolved from single crystal, through sub‐micro crystallites, and finally to crystalline nanoparticles. The most influential factors in the morphology evolution are the initial pH level, the participation of surfactant‐template F127, and the change in pH during the reaction.
Refractive Index and Density Measurements for Selected Binary Protic‐Protic, Aprotic‐Aprotic, and Aprotic‐Protic Systems at Temperatures from 298.15 K to 308.15 K
Authors: El‐Dossoki Farid I. 
Published: May 2015

AbstractThe refractive indices (n) and the densities (ρ) of: (1) protic‐protic solvent mixtures (methanol‐ethanol, methanol‐porpanol, methanol‐butanol and ethanol‐water), (2) aprotic‐aprotic solvent mixtures (acetonitrile‐dimethylformamide, acetonitrile‐dimethylsulphoxide, and acetonitrile‐1,4‐dioxane) and (3) aprotic‐protic solvent mixtures (dimethylformamide, acetonitrile with water and some aliphatic alcohols) were measured experimentally at different temperatures (25, 30 and 35 °C). From the values of the measured refractive indices and densities, the excess refractive indices (nE), molar refractions (R), atomic polarization (PA), molar volumes (V), solvated radii (r) and polarizabilities (α) of the mixed solvents were calculated.The results show that the solvent‐solvent interaction reaches maximum value at a definite mole fraction (x) of each solvent depending on its nature. Also, the excess refractive indices, densities and atomic polarizations are found to decrease as the temperature increases. On the other hand, the molar volumes, solvated radii, molar refractions and polarizabilities are found to increase as the temperature increases.
Synthesis of New Reagent Benzyloxybenzaldehydethiosemicarbazone (BBTSC): Selective, Sensitive and Extractive Spectrophotometric Determination of Pd(II) in Water Samples and Synthetic Mixtures
Authors: Narayana Suvarapu Lakshmi , Reddy Koduru Janardhan , Reddy Somala Adi Narayana , Kumar Jyothi Rajesh , Reddy Ammireddy Varada 
Published: May 2015

AbstractA new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5–60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4 × 104 Lt. mol−1 cm−1 and 0.02661 μg cm−2, respectively. The correlation co‐efficient of the Pd(II)‐BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 μg.mL−1. The instability constant of the method was calculated by Asmus' method as 3.5714 × 10−4. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.