bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of Polycyclic Aromatic Hydrocarbons Produced During Combustion of Fuel With Carbon Disulfide as Additive
Authors: Sye Wen‐Fa , Hwang Shi‐Shyan 
Published: June 2015

AbstractThat polystyrene and benzene as additives to gasoline increase the amount of polycyclic aromatic hydrocarbons (PAHs) has been studied previously in our laboratory. This paper describes the use of carbon disulfide as the solvent instead of benzene brings a marked reduction of the formation of polycyclic aromatic hydrocarbons.
Polarographic Determination of the Formation Constants of the Mixed Ligand Complexes of Cd(II) and Pb(II) with Thiosulphate and Halide Ions
Authors: Ghandour M.A. , Hassan R.M. , Ibrahim S.A. , Abo El‐Maaly N. 
Published: June 2015

AbstractThe mixed ligand complexes of Cd(II) and Pb(II) with thiosulphate as a primary ligand and chloride, bromide of iodide (individually) as a secondary ligand have been polarographically, investigated at 30°C and at a constant ionic strength of μ = 1.0 M (NaClO4). Two mixed ligand complexes were formed with the Cd(II) ion: log β12 = 4.77, 5.30 and 6.78 for the chloride, bromide and iodide ions, respectively; and log β21 = 5.36, 5.04 and 6.22 for the same ions. For the Pb(II)‐Ts‐Cl system, only one mixed ligand complex was formed with a log stability constant log β21 =4.35. For the Pb(II)‐Ts‐Br system, three mixed ligand complexes are obtained with log β11 = 3.63, log β12 = 4.51 and log β21 = 4.85.
Triazoles and Fused Triazoles II: Synthesis of Certain Substituted s‐Triazoles, s‐Triazolo[3,4‐b]‐1,3,4‐Thiadiazoles and s‐Triazolo [3,4‐b]‐1, 3,4‐Thiadiazines
Authors: El‐Emam A. A. , Moustafa M. A. , Bayomi S. M. , El‐Ashmawy M. B. 
Published: June 2015

AbstractThe synthesis of a certain series of s‐triazoles and fused s‐triazoles namely: 3‐(3,4‐dimethoxyphenyl)‐4‐arylideneamino‐5‐mercapto‐s‐triazoles 3.8, 3‐(3,4‐dimethoxyphenyl)‐6‐substituted‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles 11‐17, 3‐(3,4‐dimethoxyphenyl)‐6‐substituted thio‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles 19, 20 and 3‐(3,4‐dimethoxyphenyl)‐6‐substituted‐7H‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazines 21, 22, is described.
Chelating Resins in Analytical Chemistry
Authors: Liu Chuen‐Ying 
Published: June 2015

AbstractChelating resins, the polymeric complexing compounds, are specific and selective ion exchange resins. A chelating ion exchange resin consists essentially of two components, i.e. a chelating group and a polymeric matrix. The properties of both components affect the selectivity of the synthesized resin. Methods used to synthesize chelating resins are reviewed. The analytical and physical techniques used to characterize the dissociation constant, metal capacity and distribution coefficient of the newly synthesized resin as well as the coordination site, the composition and the formation constant of the metal‐resin complexes are discussed. Chelating resins could be used in various forms. Some important features of the analytical application of chelating resins, including selective concentration and separation both in inorganic analysis and organic analysis are also discussed. The techniques by which sorption or separation with the help of chelating resins achieved can be static, dynamic, or chromatographic. After sorptive concentration or separation, the elements can be determined either directly in the sorbent phase, its decomposition residue, the eluent solution after desorption, or the effluent after the solution has been passed through the sorbent. Various objects such as natural waters, geological objects, industrial materials, foodstuffs, coal, fuel oil. shale oil, transuranium elements and biological materials could be analyzed with the help of chelating resins.
Rapid Protein Hydrolysis by Microwave Irradiation Using Heat‐Resistant Teflon‐Pyrex Tubes
Authors: Chiou Shyh‐Horng 
Published: June 2015

AbstractA rapid peptide‐bond hydrolysis by means of microwave irradiation is introduced for the facile preparation of protein hydrolysates used for amino acid analysis. The optimal hydrolysis condition has been determined using several enzymes with known amino acid compositions. The effects of hydrolysis time on the recovery of various labile and hydrophobic amino acids are also exemplified in the microwave heating of standard amino acids. The method has been applied to the complete amino acid analysis with a single nonvolatile solvent of methanesulfonic acid with good recovery of tryptophan and half‐cystine. It provides a radical expedition of protein and peptide hydrolysis via commercial microwave ovens and specially‐designed Teflon‐Pyrex tubes, circumventing the tedious procedures using vacuum‐sealed pyrex lubes heating at 110°C for more than 24 h. This novel type of microwave chemistry associated with rapid peptide‐bond cleavage is of great potential in the automation of the complete process of amino acid analysis starting from the preparation of protein hydrolysates.
Two Hypusine‐Containing Proteins Identified by Metabolic Labeling in Chick Embryo Fibroblasts
Authors: Dou Qing‐Ping , Chen Kuang‐Yu 
Published: June 2015

AbstractIncubation of various cultured mammalian cells under growth‐stimulatory condition with [3H]putrescine or [3H]spermidine results in a labeling of an 18, 000‐dalton protein (Cell, 1982, 29, 791; BBA, 1983, 756, 395). The labeling is due to post‐translational conversion of a lysine residue to hypusine residue, using the butylamino moiety derived from spermidine. In order to search for an abundant source for the purification of this protein, we have examined possible existence of this hypusine‐containing 18, 000‐dalton protein (hyp‐18k) in chick embryos by the metabolic labeling method. Metabolic labeling of chick embryo fibroblasts, prepared from the Day 11 embryos, by [3H]putrescine resulted in two prominently labeled protein bands. Mr=18, 000 and 20, 000, as shown by sodiun dodecyl sulfate‐polyacrylamide gel electrophoresis and fluorography. Two‐dimensional gel analysis indicated that the labeled 20, 000‐dalton protein had a pI value of 5.5 and the labeled 18, 000‐dalton protein exhibited isoform structures with pI values ranging from 4.6 to 5.1. Peptide map analysis showed that these two proteins are similar but not identical. Both labeled proteins contained radioactive hypusine residue and exhibited strong binding to Cibacron Blue dye. The time course of the metabolic labeling of these two proteins, however, differed dramatically. The labeling of the 18, 000‐dalton protein appeared early and continued to increase 24 h after serum stimulation. In contrast, the labeling of the 20, 000‐dalton protein became prominent only after much longer period of incubation.
Studies on Angiotensin‐Converting Enzyme Inhibitors: Protease Catalyzed Resolution of Aryl 3‐Mercapto‐2‐Methylpropionic Ester
Authors: Chen Shui‐Tein , Wong Chi‐Huey 
Published: June 2015

AbstractOptically active 3‐benzylthio‐2‐methylpropionic acid and 3‐benzoylthio‐2‐methylpropionic acid have been prepared via protease‐catalyzed hydrolysis of their corresponding ester and thioester. Subtilisin catalyzed the hydrolysis of the thioester of methyl 3‐benzoylthio‐2‐methylpropionate twice as fast as that of the methyl ester derivative. The stability of the enzyme in organic cosolvents was studied. Immobilization of subtilisin on the solid support XAD‐8 improved the stability of the enzyme. A practical preparative resolution of the title compound is reported.
Enantioselective Syntheses of Plate Let‐Activating Factor and a Phospholipase A2 Inhibitor from Chiral Synthons Prepared Enzymatically
Authors: Wanc Yi‐Fong , Wong Chi‐Huey 
Published: June 2015

AbstractEfficient procedures have been developed for the stereospecific syntheses of platelet‐activating factor and its 2‐acetamido analog, an inhibitor of phospholipase A2. (S)‐3‐O‐Actyl‐2‐O‐benzylglycerol and (S)‐2‐N‐benzyloxycarbonyl‐3‐O‐valerylserinol are used as starting materials for the syntheses. Both chiral synthons are prepared from lipase‐catalyzed acetylation and hydrolysis of the corresponding meso precursors.
Synthesis of [1, 2‐13C2]‐S‐Lysine Hydrochloride
Authors: Yuan Sun‐Shine , Ajami Alfred M. 
Published: June 2015

AbstractCobalt catalyzed hydroformylation‐amidocarbonylation of 3‐cyanopropene by carbon‐13 monoxide and acetamide produced a [1,2‐13C2]‐labelled mixture of 5‐cyano‐2‐acetamidopentanoic acid and 4‐cyano‐3‐methyl‐2‐acetamidobutanoic acid (n to b ratio of 7 to 3. 55% yield). Acylase I resolution of this mixture gave the free S‐amino acids which could be separated by crystallization. Catalytic reduction of the cyano group of the straight chain acid furnished [1,2‐13C2] ‐S‐lysine. HCl.
A Study of the Constituents of the Wood of Armand Pine
Authors: Fang Jim‐Min , Su Wen‐Chiung , Liang Wen‐Chuan , Cheng Yu‐Shia 
Published: June 2015

AbstractLong‐chain esters, 4‐hydroxy‐3‐methoxycinnamate esters, cinnamaldehyde, two diterpenoid acids, seven flavonoids, seven stilbenes and a novel lignan were isolated from the heartwood of Pinus armandii Franchet var. mastersiana Hayata.
Synthesis and Mossbauer Spectra Studies of Mono‐Binuclear Iron(III) Complexes with a Quinquedentate Ligand Derived from Saucylaldehyeds and Diethylenetriamine
Authors: Sheu Jinn‐Fwu , Wei Ho‐Hsiang 
Published: June 2015

AbstractMono‐ and bi‐nuclear iron(III) complexes of general formula [FeXL] and [LFe‐Y‐FeL](Bph4)2 have been prepared, and their spin state of iron atom in the complexes has been studied by means of the temperature dependence of the Mössbauer spectra, electronic spectra and magnetic measurement, where X is a mono‐ dentate ligand such as Cl‐, NCS‐, NCO‐, N3‐, pyridine and L denotes a quinquedentate Schiff base derived from salicylaldehyde and diethylenetriamine, and Y denotes bridged ligand such as pyrazine(pyr), 4,4′‐bipyridine(bpy) and 4,4′‐vinylenebipyridine(vibpy). On the basis of the Mössbauer and magnetic data, it was concluded that these complexes were all the high‐spin (S = 5/2) slate. The effect of gamma ray irradiation for these complexes has been discussed.
Characterization and Activity of Iron‐Manganese Catalysts for Carbon Monoxide Hydrogenation
Authors: Kuei Chi‐Kung , Chian Wan‐Lan , Chen Wen‐Shing , Lee Min‐Dar 
Published: June 2015

AbstractStudies on the structural changes and catalytic behavior of iron‐manganese catalysts for CO hydrogenation were conducted using Mossbauer spectroscopy, X‐ray diffraction, temperature programmed reduction and kinetic measurements. It was observed that the reduction of the mixed oxide catalyst precursors proceeds via the formation of Fe3‐xMnxO4,Mn3‐xFexO4 mixed spinel and Fe1‐zMn2O mixed oxide to α‐iron and MnO. After use for CO hydrogenation, catalysts are oxidized as well as carburized. The Mn3‐yFeyO4 mixed spinel and Fe1‐2MnzO mixed oxide are the most powerful phases for olefin production. The highest attainable 2–4 low carbon olefin selectivity is 41% with an 86% conversion level. Higher manganese content or lower reduction temperatures may change the carbide formed from χ‐Fe5C2 to the more unstable ϵ′‐Fe22C. Carbide formation is greatly dependent on manganese content and activation procedure used.
The McConnell Relation of Newly Modified Indo‐Mo Method
Authors: Chen Cheng 
Published: June 2015

AbstractThe s‐p separation model INDO‐MO method has been introduced and developed for open and closed shell problems1–3 In order to demonstrate the importance of σ–π interaction between 2pπ of carbon and 1s of hydrogen in this newly modified MO1 we apply “McConnell Relation”4–7 to a linear correlation calculation 122 data points of 1H hyperfine coupling constant in the cases of free radicals and ions with π type SOMO (singly occupied molecular orbital). The calculated McConnell constant, Q, is equal to −24.6 gauss. The standard deviation and correlation coefficient of this statistical treatment are 1.011 gauss and 0.980, respectively. Most of the results in this calculation are reasonable.
Spirodialkylation of 3‐(Phenylthio)‐3‐Sulfolene and Subsequent Synthetic Transformations
Authors: Chou Shang‐Shing P. , Sung Chin‐Chuan 
Published: June 2015

Abstract3‐(Phenylthio)‐3‐sulfolene (1) underwent spirodialkylation to give products 2 which were desulfonylated to afford the dienes 3. The Diels‐Alder reaction of 3 was achieved for some reactive dienophiles to yield spiro compounds. Compounds 2 were also converted to sulfonyldienes 9 which reacted as Michael acceptors.
Laser‐Induced Addition Reactions of Iodine with Acetylene
Authors: Chen Kuo‐Mei , Wang Gaw‐Pying , Kuo Chen‐Nan , Chen Jui‐Chi 
Published: June 2015

AbstractLaser‐induced addition reactions of iodine with acetylene at 5145 and 4880 Å excitation wavelengths are studied, while trans‐1,2‐diiodoethylene is identified as the exclusive reaction product. A sequential addition reaction mechanism initiated by iodine atoms from the direct photodissociation process or collisional induced dissociation can be inferred.
Inhibitive Effect of Butyltin Trichloride on Dissolution and Localized Corrosion of Aluminium in Sodium Hydroxide and Hydrochloric Acid
Authors: Mourad M.Y. , Ibrahim E.H. , Seliman S.A. 
Published: June 2015

AbstractThe dissolution of aluminium in sodium hydroxide and hydrochloric acid in the presence of butyltin trichloride as corrosion inhibitor has been studied by hydrogen evolution and thermometric methods.Experimental findings indicate that the inhibition effect of butyltin trichloride takes place through an adsorption mechanism following the Frumkin's isotherm.Butyltin trichloride acts as a weakly adsorbed inhibitor in NaOH and as a strongly adsorbed inhibitor in hydrochloric acid medium.
Studies on the Preparation and Biological Activities of 3‐(O‐Methoxybenzyl)Sydnone Derivatives and 3‐(Fluorophenyl)Sydnones
Authors: Tien Hsien‐Ju , Tsai Yan‐Hong , Yeh Wen‐Yuan , Yeh Jong‐Chuan , Lee Yaw‐Kuen , Ho Young‐Shang 
Published: June 2015

AbstractTwo new sydnones; 3‐(o‐methoxybenzyl)sydnone(1) and 3‐(o‐melhoxybenzyl)‐4‐morpholinomethylsydnone(2) were synthesized from o‐methoxybenzylamine and ethyl bromoacetat in moderate yields.3‐(o‐,m‐,p‐Fluorophenyl)sydnones were prepared from the corresponding fluoroaniline and chloroacetic acid in higher yields with a conventional method.From the biological activity test, 1 shows significant response of coronary dilation test, collagen induced platelet aggregation inhibition, local anesthetic and moderate cardiotropic activity. In addition, 1 also leads to anticonvuls, muscle relaxation and behavior depression. But 2 only shows inhibition of collagen induced platelet aggregation and antiwrithing.3‐(p‐Fluorophenyl)sydnone (5) shows significant response of coronary dilation, collagen induced platelet aggregation inhibition, moderate cardiotropic activity, antiwrithing and local anesthetic But 3‐(o‐Fluorophenyl)sydnone(3) and 3‐(m‐fluorophenyl)sydnone(4) only show coronary dilation and moderate cardiotropic activity.
The Studies of Free Radical Cyclization Reactions Mediated by Sulfonyl Chloride (I)
Authors: Chuang Che‐Ping , Hou Sheng‐Shu , Ngoi Tak Ho, Johnny 
Published: June 2015

AbstractA study of the free racinoal reaction of vinylcycloprelpane mediated by p‐toluenesulfonyl chloride is described.
Ammonia Chemical Ionization Mass Spectra of Sydnones
Authors: Lin Shaw‐Tao , Tien Ling‐Ling 
Published: June 2015

AbstractThe mass spectra of twenty‐nine sydnones were measured by using NII3 as a reagent gas. The [M + H + NH3]+ ions are the base peaks for the entire series. Very few fragment ions were observed except for the derivatives of 4‐hydroxymethylenesydnones (XXI‐XXIX). Only the relatively stable sydnonyl‐methylene cations are formed. With consistent formation of [M + 18]+ ion as the base peaks with simple spectra, the NH3 CI‐MS can be an excellent method for the molecular weight determination.
Temperature Programmed Reduction and Spectroscopic Studies of Reduction Behavior of fe/tiO2 Catalyst
Authors: Chien Shu‐Hua , Chiang Wan‐Lan 
Published: June 2015

AbstractFe/TiO2 catalyst was prepared by incipient wetness impregnation of TiO2 with aqueous solution of ferric nitrate. The reduction behavior of the catalyst was studied by temperature programmed reduction profiles, Mössbauer spectroscopy, x‐ray diffraction and x‐ray photoelectron spectroscopy. The results show that the reduction of Fe/TiO2 was accompanied by a phase transition of anatase to rutile titania. α‐Fe2O3 was reduced to Fe3O4 in the initial reduction stage. Due to the strong support effect of TIO2, FeTiO3 was gradually formed as the reduction temperature reached 450°C. Complete reduction to the metallic Fe° particles occurred at temperatures higher than 670°C. The anatase‐rutile transition was initiated by the reduced Ti3+ ions and led to the formation of TiOx. At higher reduction temperature, TiOx migrated to the surface of metallic Fe° particles forming FeTiOx in the so‐called strong metal‐support interaction (SMSI) state.
Determination of the Molecular Weight and Particle Radius of Gelatin Micelles by Sedimentation and Optical Mixing Spectroscopy
Authors: Hwang Jeng‐Shung , Gi Hung‐Jang , Chen Shou‐Nan 
Published: June 2015

AbstractMicelles formed from gelatin solutions were studied by sedimentation and optical mixing spectroscopy (OMS). We sampled gelatin solutions at various centrifugal speeds. Single exponential autocorrelation functions of the gelatin solutions were measured at 27°C and at 90° scattering angle by OMS. Calculation of the diffusion coefficient D from the measured autocorrelation function of scattered light has been carried out in this studied. A calculation of the micellar radius from the Stokes‐Einstein equation was carried out. We also calculated the sedimentation coefficient and molecular weight of gelatin micelles and found that the polydisperse gelatin micelles were formed at 50mg/mL.
Collisional Deactivation of K(7s2S) and K(5d2D) by No
Authors: Chang Min‐Lung , Huang Jui‐Tsen , Lin King‐Chuen 
Published: June 2015

AbstractRadiative lifetimes and total deactivation cross sections of K(72S) and K(52D) by collision with NO are studied. The K atomic vapor in either the 72S or the 52D state was prepared by two‐ photon absorption using a dye laser. The decay signal of the time‐resolved fluorescence from the 72S – 42P1/2 or 52D – 42P3/2 transition was then monitored. Based on a Stern‐Volmer analysis, the radiative lifetimes are 155 ±8 ns and 561 ± 18 ns for the K(72S) and K(52D) states, respectively. The total deactivation cross sections are 88 ±1Å2 and 70 ±2Å2 for the K(72S)‐NO and K(52D)‐NO collisions, respectively. In the absence of NO collisions the radiative lifetimes obtained in this work show excellent agreement with those previously reported. The quenching cross sections for NO have been measured for the first time, and have values in a reasonable range, when compared with Na‐N2 collisions.
Two‐Photon Spectroscopy of Acetylene ‐ Photodissociation Processes at 9‐10 eV Energy Levels
Authors: Lee Ing‐Fang , Lee Yuan‐Hsiang , Hsu Yen‐Chu 
Published: June 2015

AbstractThe gerade states of acetylene at 9‐10 eV have been studied by monitoring the C2 emission. Larger Δv2 excitations are seen than previously reported by Ashfold et al. The observed two‐photon resonant levels show extensive predissociation. Experimental evidence from the two‐color photofragment excitation measurement is given to support the conclusion that the excited‐state ethynyl radical and atomic hydrogen are the corresponding predissociation products. Most C2 emissions seen in this work are due to the subsequent photodissociation of the intermediate C2H to C2 (d3Πg).
Adsorptive Bubble Separation of Dinitrophenol
Authors: Shing Ank‐Kung , Huang Shang‐Da 
Published: June 2015

AbstractDinitrophenol was removed from aqueous solution by various adsorptive bubble separation techniques. Foam fractionation of dinitrophenol with hexadecyltrimethylammonium bromide(HTA) was most effective with over 99% removal in 15 min. The addition of a surfactant in greater than stoichiometric amounts was required for effective separation. Solvent sublation of the dinitrophenol‐HTA complex was also effective. The separation efficiency of solvent sublation of dinitrophenol‐HTA was similar to that of foam fractionation. The separation by solvent sublation of dinitrophenol without adding any surfactant was very poor. Adsorbing colloid flotation with Fe(OH)3 was not effective in removing dinitrophenol from aqueous solution.
Studies on 1,2‐Bis(O‐Aminophenoxy)Ethane‐N,N,N′,N′;‐Tetraacetic Acid Chelates of the Tripositive Lanthanide Ions
Authors: Hseu Tong‐Ming , Liu Kei‐Lee 
Published: June 2015

AbstractThe acid dissociation constants of 1,2‐bis(cis‐aminophenoxy)ethane‐N,N,N′,N′;‐tetraacetic acid (H4BAPAT or H4Z), and the stability constants of its chelates with tripositive rare‐earth metal ions have been determined by the potentiometric titration and mercury indicator electrode methods at 15°, 25′ and 35°C and an ionic strength of 0.1 (KNO3). The existence of a monohydrogen chelate species, LnHZ, and the normal chelate, LnZ−, is illustrated. Enthalpy and entropy changes characterizing the formation of the normal chelates and the dissociation of the last two protons of chelating acid have been calculated at 25°C. These functions have been compared with corresponding values for related chelating agents.
Preparation and Catalytic Properties of Transition Metal Doped ZSM‐5 Zeolites
Authors: Wan Ben‐Zu , Yang Tran Chin 
Published: June 2015

AbstractMetal silicates of ZSM‐5 type structure were prepared by doping silicate gels with chromium, manganese, cobalt, nickel, and copper ions, respectively, followed by reacting hydrothermally. The resultant materials were characterized by the metal content, x‐ray powder diffraction, ion exchange capacity, surface area, thermal stability, and temperature programmed desorption of ammonia for acidity measurement. In addition, the catalytic properties of these metal silicates were examined using ethanol conversion as a probe reaction. The effect of transition metal content on the catalysis for dehydration, dehydrogenation, oligomerization, cracking, and cyclization to the aromatics was established and compared with that of HZSM‐5 catalyst.
Characterization of the SiOT Angle and Cation Effects on 29Si Chemical Shifts Of Zeolites
Authors: Su Ming‐Der , Chao Kuei‐Jung , Chu San‐Yan , Chen Cheu‐Pyeng 
Published: June 2015

AbstractThe quantitative relationships between 29Si chemical shifts and (a) the SiOT (T = Al or Si) angles and (b) the nature of the cations of the alkali forms of zeolites can be account for by the changes of charge density and p electron population of the Si atoms as calculated by the extended Hückel method on cluster models.
Selective Alkaline Protease Catalyzed Hydrolysis of Peptide Esters
Authors: Chen Shui‐Tein , Chang Chung‐Ho , Lin Johnson , Wang Kung‐Tsung 
Published: June 2015

AbstractProcedures for preparing C‐terminal free peptides from hydrolysis of its corresponding methyl or benzyl esters catalyzed by alkaline protease has been developed. N‐protected peptides having side‐chain ester protecting groups or successive hydrophobic amino acid residues in its sequence are hydrolyzed selectively at C‐terminal only and leave other bonds (β and γ‐ ester or peptide bonds) intact. Compounds which cause a side reaction in base mediated saponification could be hydrolyzed safely by this procedure. Products of this hydrolysis are useful intermediates for fragments coupling in the solid phase peptide synthesis.