bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Total Iron in Environmental Samples by Solid Phase Extraction with Dimethyl(E)‐2‐(2‐Methoxyphenoxy)‐2‐Butenedioate
Authors: Khayatian Gholamreza , Kolaie Hamidreza Ahmadzadeh Vosta , Nasiri Farough , Atashkar Bahareh , Hassanpoor Shahed 
Published: May 2015

AbstractA novel solid phase extraction technique for determination of total iron in environmental water samples was developed. The method is based on sorption of Fe(III) ions on octadecyl silica membrane disk modified with a new synthetic ligand dimethyl(E)‐2‐(2‐methoxyphenoxy)‐2‐butenedioate (I). Iron(III) is quantitatively retained on the disk in the pH range of 3–7 at a flow rate of 1–7 mL min−1. The Fe(III) eluted with 10 mL of 0.01 M EDTA and than was measured by flame atomic absorption spectrometry (FAAS) at 248.3 nm. The maximum capacity disk modified by 7 mg of ligand was found to be 197 ± 2 μg of iron(III). The breakthrough volume was greater than 2000 mL. The iron(III) was completely recovered (> 99%) from water with a preconcentration factor of more than 200. The limit of detection of the proposed method was 1.00 ng mL−1. The various cationic and anionic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was successfully applied to determination of total iron from three different water samples.
Synthesis and Characterization of Achiral Bent‐Core Liquid Crystalline Molecules Containing Salicylaldimine‐Based with a Wide Temperature Range of SmCP Phase
Authors: Liao Chien‐Tung , Liu Jung‐Yo , Zou Sing‐Fang , Wu Nien‐Chieh , Wu Zheng‐Long , Lee Jiunn‐Yih 
Published: May 2015

AbstractThe design and synthesis of a series bent‐core materials base on a 3,4′‐biphenyldiol central core containing salicylaldimine‐based and two terminal tetradecyloxy tails are reported. In addition, the effects of lateral substituents (R = F and Cl) at the biphenyl core into 3′‐position are examined. These substituents have a strong influence in reducing the clearing temperatures and increasing temperature range of SmCP phase. Upon cooling process the isotropic liquid, compound SB‐Cl exhibits the lowest clearing transition temperature of 180°C and the widest SmCP phase range of 129°C. The mesophase behaviour were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and electro‐optical (EO) measurements in the mesophase temperature range.
Metallopeptides — from Drug Discovery to Catalysis
Authors: Ming Li‐June 
Published: May 2015

AbstractOligopeptides are involved in diverse biological activities, including neurotransmission and antibiotic. Many natural‐occurring peptides and peptide‐ketide hybrids exhibit specific biological activities and chemical reactivities upon binding with certain metal ions, such as divalent metal‐binding antibiotic bacitracin and anticancer Fe/Cu‐bleomycin. There are also numerous synthetic peptides designed to bind metal ions to exhibit wide range of physical properties and chemical and biological activities. In this review we summarize the background and discuss our research on metal binding properties, structures, and chemical reactivities of three metallopeptides, the bacterial antibiotic bacitracin, the Alzheimer's disease‐related β‐amyloid, and the salivary antimicrobial histatin. Despite their different structures and biological functions, the Cu2+ complexes of these peptides exhibit significant activities toward catechol oxidation and phenol hydroxylation. However, the mechanisms of the oxidative reactions among these three Cu‐peptides seem to be distinctively different. Our current understanding about the structure‐bioactivity relationship and chemical reactivities as well as implications in drug discovery of these peptides are summarized herein.
A Novel Approach for the Solid‐Phase Organic Synthesis of 1, 3‐Disubstituted Uracils
Authors: Wei Mei‐Hong , Lin Shu‐Ying , Sheng Sheng‐Ri , Wang Qing , Cai Ming‐Zhong 
Published: May 2015

AbstractA novel procedure for solid‐phase organic synthesis of 1, 3‐disubstituted uracils using a cyclization‐cleavage strategy from Wang‐acrylate resin, amines and isocyanates. An acrylate ester resin is reacted in turn with PhSeBr and primary amines in one‐pot to afford N‐substituted α‐phenylseleno‐β‐aminoesters followed by treatment with isocyanates to form α‐phenylseleno‐β‐ureidoester resin. Following oxidation‐elimination with excess of 30% hydrogen peroxide and intramolecular cyclization cleavage of the Wang resin using potassium ethoxide as a base to furnish 1, 3‐disubstituted uracils in good yields (80‐86%) and high purities (92‐96%).
Synthesis and Characterization of a Novel Benziloxime Ligand and Its Iron(III) and Nickel(II) Complexes
Authors: Soleimani Esmaiel 
Published: May 2015

AbstractThe synthesis of a novel benziloxime ligand, 4,4′‐dibromobenzilmonoxime (DBBOH) (1) and its complexes [Fe(DBBO)3] (2) and Na[Ni(DBBO)3] (3) are described. The ligand (DBBOH) was prepared in MeOH from the reaction of 4,4′‐dibromobenzil with hydroxylamine hydrochloride in the presence of sodium acetate.Reaction of sodium salt of 4, 4′‐dibromobenzilmonoxime (DBBONa) in MeOH with Fe(NO3)3.9H2O and Ni(NO3)2.6H2O yielded [Fe(DBBO)3](2) as yellow and Na[Ni(DBBO)3] (3) as brown precipitates respectively.The ligand, 4, 4′‐dibromobenzilmonoxime (DBBOH) (1) and its complexes [Fe(DBBO)3](2) and Na[Ni(DBBO)3] (3) were characterized by elemental analysis, 1H‐NMR and 13C‐NMR, IR, and electronic spectral studies.The analysis of IR, 1H‐ and 13C‐NMR spectral data of Fe(III) and Ni(II) complexes suggest that 4,4′‐dibromobenzilmonoximate is bonded to iron(III) and nickel(II) ions through the oxygen atom of the carbonyl, and the nitrogen atom of the imine groups. The electronic spectral data of the complexes in CHCl3 are in good agreement with the octahedral coordination of Fe(III) and Ni(II) ions. The ligand field parameters for these complexes, i.e. splitting energy and Racah parameter were calculated to be 21560 cm−1 and 707 cm−1 for [Fe(DBBO)3] (2), 13440 cm−1 and 610 cm−1 for Na[Ni(DBBO)3] (3) respectively.
Dissolution of 3,4,5‐Triamino‐1,2,4‐triazole Dinitramide in N‐Methyl Pyrrolidone
Authors: Xue Liang , Zhao Feng‐Qi , Xing Xiao‐Ling , Zhou Zhi‐Ming , Wang Kai , Gao Hong‐Xu , Yi Jian‐Hua , Hu Rong‐Zu 
Published: May 2015

AbstractThe dissolution properties of 3,4,5‐triamino‐1,2,4‐triazole dinitramide in N‐methyl pyrrolidone (NMP) was measured using a RD496‐2000 Calvet microcalorimeter at four different temperatures under atmospheric pressure. Differential enthalpies (ΔdifH) and molar enthalpies (ΔsolH) were determined for 3,4,5‐triamino‐1,2,4‐triazole dinitramide in NMP. The corresponding kinetic equations that describe the four dissolution processes are \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{{\rm d\alpha }}}{{{\rm d}t}} = 1.78 \times 10^{ - 4} \left({1 - {\rm \alpha }} \right)^{1.01} \left({T = 298.15{\rm K}} \right) $\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{{\rm d\alpha }}}{{{\rm d}t}} = 1.96 \times 10^{ - 4} \left({1 - {\rm \alpha }} \right)^{1.06} \left({T = 303.15{\rm K}} \right) $\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{{\rm d\alpha }}}{{{\rm d}t}} = 2.15 \times 10^{ - 4} \left({1 - {\rm \alpha }} \right)^{0.96} \left({T = 308.15{\rm K}} \right) $\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{{\rm d\alpha }}}{{{\rm d}t}} = 2.34 \times 10^{ - 4} \left({1 - {\rm \alpha }} \right)^{1.06} \left({T = 313.15{\rm K}} \right) $\end{document} solution of 3,4,5‐triamino‐1,2,4‐triazole dinitramide in NMP, respectively. The values of activation energy E and pre‐exponential factor A for the dissolution process are obtained as 14.13 kJṁmol−1 and 5.34 × 10−2 s−1.
Synthesis and Characterization of Uniform Fine Particles of Nickel Compounds
Authors: Haq Ikram Ul , Haider Farzana 
Published: May 2015

AbstractNickel oxalate particles were prepared by mixing aqueous solutions of nickel sulfate and oxalic acid at 25 and 85 °C. Effect of composition of the reacting solutions and pH of the resulting dispersion was evaluated on morphology of the precipitated particles. Besides these parameters, isoelectric point of the nickel oxalate played a major role in the particles build up. On control heating at 340 °C, the nickel oxalate particles converted into nickel oxide particles while preserving their particles' integrity to a maximum extent. Selected batches of the as‐prepared and heat‐treated particles were characterized by various physical methods.
Fast Analysis of Phenolic Acids by Microchip Capillary Electrophoresis with Serpentine Channel and End Wrapped Electrode
Authors: Cheng Hsien‐Yu , Chen Show‐Chuen , Lee Hui‐Ling 
Published: May 2015

AbstractA microchip capillary electrophoresis with amperometric detection, μCE‐EC, for the analysis of phenolic acids is described. The problem of noise‐laden signal under high electric field was tackled by adopting the end‐channel design of electrode configuration: more specifically with the end‐wrapped electrode configuration. At full stretch of effort, a finely tuned electrode could bring the detection limit well below micro molars for dopamine. At the end of the 10‐cm serpentine micro‐channel, a Pt electrode biased at +0.9 V (vs. Ag/AgCl) served as the working electrode. Injection of gentisic acid, protocatechuic acid, vanillic acid, p‐coumaric acid, caffeic acid, ferulic acid, sinapic acid and chlorogenic acid gave repeatable results: the migration time deviating within 3.80% (n = 7) and peak current between 1.45 and 4.50%. Under the optimized conditions, the detection limits for phenolic acids could be brought down to the range between 1.82 μM and 19.85 μM at S/N = 3. The regression coefficient of the calibration curve over the range between 10 and 800 μM was better than 0.995. The merits of increased efficiency with serpentine channel and improved sensitivity with end‐wrapped electrode are promising. Beer samples were tested for feasibility as a routine tool.
Rapid Identification of the Antioxidant Constituent of Koelreuteria Henryi
Authors: Chen Chin‐Hui , Chen Pi‐Yu , Wang Kuang‐Chuan , Lee Ching‐Kuo 
Published: May 2015

AbstractIn recent years, on‐line coupling of separation and activity determination techniques has been achieved by mixing a free radical solution with the eluate of an HPLC column. Such techniques enable the rapid and selective detection of radical scavenging substances in the sample preparation. This study investigates the antioxidant properties of the leaves of Koelreuteria henryi L. using a microarray reader and HPLC. The antioxidant, 1,3,4,5‐tetra‐O‐galloylquinic acid (1), was first isolated from this plant and estimated using LC‐MS/MS and NMR methods. The scavenger activity of (1) was then determined using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical and xanthine oxidase (XOD) assays, producing an IC50 of 7.1 μM and 6.7 μM, respectively. Results show that this compound has an excellent antioxidant effect in comparison with quercetin.This study shows that it is possible to rapidly identify the antioxidant constituents of K. henryi L. using the hyphenated DPPH (or XOD) assays and LC‐MS/MS methods.
QSAR Study on ACE Inhibitors by Using OSC‐PLS Algorithm
Authors: Long Hai‐Xia , Wang Yuan‐Qiang , Lin Yong , Lin Zhi‐Hua 
Published: May 2015

AbstractA set of descriptors was derived from a matrix of three structural variables of the natural amino acid, including Van Der Waal's volume, net charge index and hydrophobic parameter of side residues. They were selected from many properties of amino acid residues, which were the primary properties to influence the interaction between peptides and its protein receptor. They were then applied to structure characterization and QSAR analysis on agiotensin‐converting enzyme inhibitor di‐peptides by using orthogonal signal correction (OSC) method combined with partial least squares (PLS) method. The results of QSAR analysis on di‐peptides obtained are as following: the cross‐validation correlative coefficient (Q2) was 0.817, and the correlative coefficient (R2) was 0.838, and the root mean‐square (RMS) was 0.410. Test sets of peptides were used to validate the quantitative model, and it was shown that all these QSAR models had good predictability for outside samples. The results showed that, in comparison with the conventional descriptors, this descriptors was a useful structure characterization parameter for peptide QSAR analysis, and also showed that the OSC‐PLS method is better than the traditional PLS method.
A Review on the Emitting Species in Conjugated Polymers for Photo‐ and Electro‐luminescence
Authors: Chen Show‐An , Jen Tzu‐Hao , Lu Hsin‐Hung 
Published: May 2015

AbstractIn conjugated polymers, fluorescence from a single polymer chain, which is contrasted with measurements on an ensemble or bulk collection of molecules, can provide important information about conformation of single polymer chain and energy transfer between different conjugation length segments within single polymer chain. On the other hand, the presence of intrachain or interchain interactions plays an important role on their photoluminescence (PL) and electroluminescence (EL) properties. In addition to non‐interacting isolated chain, there are five interacting emitting species, namely: photo‐excited dimers including excimer and exciplex, electrical‐excited dimers including electromer and electroplex, and aggregate. Excimer, exciplex, and aggregate can lead to a generation of new peak with featureless structure on the longer wavelength side in the fluorescence spectrum and usually cause a lowering in PL quantum efficiency. These three emitting species can be observed in both PL and EL spectra. In addition, electromer and electroplex only appear in EL spectrum but not in PL spectrum. The presence of electromer and electroplex also leads to a new peak at longer wavelength side. Another non‐interacting ground‐state emitting species, β phase, consists of a chain segment with a more coplanar conformation and therefore results in a longer conjugation and clear vibronic transitions.
Blocked Electron Transfer and Suppressed Blinking of Single CdSe/ZnS Quantum Dots in Agarose Gel
Authors: Ko H. C. , Yuan C. T. , Lin S. H. , Tang Jau 
Published: May 2015

AbstractFluorescence blinking is an interesting phenomenon commonly observed in single molecule/particle spectroscopy and has attracted wide interest recently. Such behavior in quantum dots is undesirable for applications as fluorescence markers. In this report, we observed suppressed blinking for single CdSe/ZnS quantum dots mixed in agarose gel. We attributed the suppression to an increase in activation energy so that the charge transfer is blocked from the neutral light state to the charged dark state as the gel concentration increases.
Effect of Broken Symmetry on the First Hyperpolarizability of a Centrosymmetric Molecule with an Application to Furan‐Containing [2.2]Cyclophandiene
Authors: Chang Yao‐Wen , Jin Bih‐Yaw 
Published: May 2015

AbstractThe effects of broken symmetry on the first hyperpolarizability for centrosymmetric molecules are studied with the so‐called VB‐4CT model. We show that the first hyperpolarizability can be enhanced dramatically when certain centrosymmetric molecules with intrinsic bistable adiabatic potential surface has its symmetry broken due to the external asymmetric perturbation, albeit this value should vanish when no any asymmetric external field is present. Particularly, we discover that the stiffness of molecular geometry and the susceptibility to weak asymmetric perturbation are related to the extent of charge‐transfer exciton in its electronic ground state. This mechanism is then successfully applied to the exceptionally high first hyperpolarizability of furan‐containing [2.2]cyclophandiene with inversion symmetry by combining the simple VB‐4CT model and quantum chemical calculation.
Applications of Surface‐Functionalized Diamond Nanoparticles for Mass‐Spectrometry‐Based Proteomics
Authors: Wu Chih‐Che , Han Chan‐Chung , Chang Huan‐Cheng 
Published: May 2015

AbstractBuilding upon recent success, diamond nanoparticles or nanodiamonds (NDs) for short have emerged as a promising new nanomaterial for biological applications. The material holds several unique properties, such as low chemical reactivity, small particle size, large specific surface area, wide optical transparency range, and facile surface functionalizability, making it a useful substrate for affinity purification mass spectrometry. Experiments have shown that the surface of NDs can be readily modified with diverse functional groups for either covalent or noncovalent conjugation with biomolecules. Additionally, NDs conjugated with bioactive ligands or polymers can be used as high affinity probes for selective extraction and enrichment of molecules of interest for characterization by mass spectrometry. This article summarizes the results of our work in employing surface‐functionalized NDs as a unique solid‐phase extraction and elution platform for pre‐concentration, selective extraction, and purification of targeted biomolecules prior to gel electrophoresis or matrix‐assisted laser desorption/ionization mass spectrometric analysis. Recent progress and future perspectives are discussed.
Synthesis of Novel Polyamine Fluorescence Sensors
Authors: Xi Hai‐Tao , Xiong Min‐Qiu , Wang Lei‐Lei , Hu Quan‐Zi , Sun Xiao‐Qiang 
Published: May 2015

AbstractA highly selective and efficient method for the synthesis of novel polyamine fluorescence sensors is being offered. Remarkable increase of yields was observed, due to using potassium carbonate as proton trapper. The reaction is fast and easy‐to‐run in favorable conditions which accompanying by fewer side effects.
A Study of Artificial Neural Networks for Electrochemical Data Analysis
Authors: Hsueh Kan‐Lin 
Published: May 2015

AbstractArtificial neural network has been demonstrated the capability of identifying the chemical composition from various analytical methods. This study tested the feasibility of using a single network to calculate data obtained from polarography, linear scanning voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). Computer generated data were used for network learning and testing. The network property of a single layer network was calculated at various learning cycles, learning rates, and β values of the neuron activation function. This study also evaluated two‐layer, three‐layer, and four‐layer networks. Test results conclude that a single artificial neural network could analyze various analytical data by using corresponding weight matrices. To produce accurate results, the network requires high training cycle, small β value of sigmoid function, and small learning rate. Network accuracy increase as the number of neuron increased to certain extents. Network structure plays minimum effects on the accuracy of network for a given number of neurons.
Novel Complexes of Mn(II), Co(II), and Cu(II) with Ligand Derived from Dibromobenziloxime
Authors: Soleimani Esmaiel 
Published: May 2015

AbstractThe preparation of 4,4′‐dibromobenzilmonoxime (BBOH) (1) and its complexes Na[M(BBO)3] (where M = Mn(II) (2), Co(II) (3), Cu(II) (4)) are described. The ligand (BBOH) was prepared in MeOH from the reaction of 4,4′‐dibromobenzil with hydroxylamine hydrochloride in the presence of sodium acetate.Reaction of sodium salt of 4,4′‐dibromobenzilmonoxime (BBONa) in MeOH with Mn(CH3COO)2.4H2O, Co(CH3COO)2.4H2O and Cu(CH3COO)2.H2O yielded Na[Mn(BBO)3] (2), Na[Co(BBO)3] (3), and Na[Cu(BBO)3] (4) precipitates respectively.The analysis of IR, 1H‐ and 13C‐NMR spectral data of Mn(II), Co(II) and Cu(II) complexes suggest that 4,4′‐dibromobenzilmonoximate is bonded to metal(II) ions through the oxygen atom of the carbonyl, and the nitrogen atom of the oxime groups. The electronic spectral data of the complexes in DMSO are in good agreement with the octahedral coordination of M(II) ions.The splitting energy and Racah parameter were calculated to be 17136 cm−1 and 816 cm−1 for Na[Mn(BBO)3] (2), 15200 cm−1 and 733 cm−1 for Na[Co(DBBO)3] (3) respectively.
QSAR Studies of 3,3′‐(Substituted‐Benzylidene)‐Bis‐4‐Hydroxycoumarin, Potential HIV‐1 Integrase Inhibitor
Authors: Li Bo‐Jian , Chiang Chih‐Chia , Hsu Ling‐Yih 
Published: May 2015

AbstractA series of biscoumarins against HIV‐1 integrase was subjected to quantitative structure‐activity relationship (QSAR) analysis. The result of the study showed that the inhibitory activity, as determined in the cell culture model, was highly correlated with the electronic (LUMO) and lipophilic effects exhibited by the substitution (R). The relationship can be expressed by the following regression equation: pIC50 = −1.903 (± 1.962) + 0.442 (± 0.066) logP − 4.504 (± 1.788) εLUMO.
Surface Plasmon‐Induced Photoluminescence in Au‐CdSe Hybrid Architectonic Solids
Authors: Chen Wei‐Hung , Ko Wen‐Yin , Fu Shu‐Juan , Zeng Ching‐Hua , Lin Kuan‐Jiuh 
Published: May 2015

AbstractWe have dramatically induced the photoluminescence intensity of CdSe quantum dots emitted from plasma antennas, an intuitive picture consisted of a dense shell of CdSe nanocrystals spontenously deposited onto Au metallic grating nanowires which result from the connection of Au nanocrystals through hydrogen bonding. The Au‐CdSe nanowires exhibit a remarkable red‐shift surface plasmons energy band (77 nm) from 529 to 606 nm with respect to the complex‐like colloids in a methanol solution and induced a narrower solid‐state band‐edge photoluminescence at 625 nm with a peakwidth of 23 nm.
Me3SiOTf Promoted Aza‐Michael Addition Reaction of 1°‐Amides with α,β‐Unsaturated Ketones
Authors: Lee Adam Shih‐Yuan , Lin Mei‐Chun , Lin Chih‐Chen , Chang Yu‐Ting 
Published: May 2015

AbstractLewis acid, Me3SiOTf, has been shown to be a promising promoter for aza‐Michael reaction of relatively acidic primary amide with α,β‐unsaturated ketone. A sries of α,β‐unsaturated ketones was transformed to their corresponding β‐amido ketones with moderate yields under this reaction condition.
A Rapid, Solvent‐Free Phase‐Transfer Catalysis Procedure for N‐Alkylation of Dihydropyridones and Construction of the Indolizidine, Quinolizidine and Pyridoazepine Structures
Authors: Chou Shang‐Shing P. , Liu Chih‐Fen 
Published: May 2015

AbstractWe have developed a solvent‐free phase‐transfer catalysis (PTC) method for the N‐alkylation of sulfur‐substituted dihydropyridone 4a to give products 5 with varying side‐chains and functional groups. Treatment of the chlorides 5a and 5c with NaI in acetone at reflux gave high yields of the iodides 6a and 6b. The reaction of iodides 7a and 7b with t‐BuLi at low temperature, followed by sequential treatment with HOAc and NaBH4, resulted in the formation of quinolizidine 8a and pyridoazepine 8b, respectively. Similar reaction of bromide 5j with t‐BuLi gave indolizidine 11.