bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymer Coated Piezoelectric Quartz Crystal Protein Bio‐Sensors
Authors: Hsu Hui‐Ping , Shih Jeng‐Shong
Published: May 2015

A polymer coated piezoelectric crystal detection system with a home‐made computer interface for signal acquisition and data processing was prepared as a liquid chromatographic detector for various proteins. Various polymers, e.g., polyvinyl aldehhyde (polyacrolein) (PVA), polyacrylamide/glutaldehyde (PAA/GA) and bio‐gel A, were used as coating materials on quartz crystals for adsorption of various protein molecules, e.g., catalase (CA), hemoglobin (Hb), α‐chymotrypsin (Ch), albumin (Ab). The frequency responses of the polyacrlein coated piezoelectric detector for various proteins were in the order: catalase> hemoglobin> α‐chymotrypsin > albumin. In contrast, the order of the frequency responses of bio‐gel A and polyacrylamide/glutaldehyde coated piezoelectric crystals for these proteins were: hemoglobin> catalase > α‐chymotrypsin ≥ albumin and hemoglobin > albumin > catalase. The polyacrolein coated piezoelectric crystal protein detector exhibited a good linear frequency response with a high sensitivity of about 2.5×103 Hz/(mg/mL) for catalase. In addition, bio‐gel A and polyacrylamide/glutaraldehyde coated crystals were sensitive to hemoglobin with sensitivities of about 4.5×103 Hz/(mg/mL) and 3.0×103 Hz/(mg/mL), respectively. Study of the interference of various organic molecules, e.g., alcohols, amines, ketones and carboxylic acids, in the detection of proteins with theses polymer coated crystals was also made. The polyacrolein coated crystal for proteins under went less interference from various organic molecules than bio‐gel A or polyacrylamide/glutaraldehyde coated crystals. Effects of coating load, concentration of proteins and flow rate of liquid chromatographic eluent were also investigated and discussed.
Indirect Determination of Ascorbic Acid with Ammonium Sulfate and Ethanol by Extraction and Flotation of Copper
Authors: Shen Yi‐Yang , Li Quan‐Min , Wei Wei
Published: May 2015

A new method of indirect determination of ascorbic acid with ammonium sulfate and ethanol by extraction and flotation of copper in the presence of thiocyanate has been studied in this paper. The study shows that a small amount of Cu(II) is reduced to Cu(I) by ascorbic acid, then Cu(I) precipitates with SCN−. In the course of phase separation of ethanol from water, the precipitated CuSCN is extracted and stays in the interface of ethanol and water. A good linear relationship is observed between the extraction yield of Cu(II) and the amount of ascorbic acid. The detection limit for ascorbic acid is 1 10−5 M. Every parameter has been optimized and the reaction mechanism has been studied. The method is simple, rapid (5 min) and suffers from few interferences of common anions and cations. It has been successfully applied for the determination of ascorbic acid in pharmaceuticals and fruits.
Total Synthesis of Kaempferol and Methylated Kaempferol Derivatives
Authors: Lee Yean‐Jang , Wu Tsao‐Dong
Published: May 2015

Kaempferol (1), a natural product from various plants, was synthesized in which the longest linear sequence is only seven steps in over all yields of 47% from commercially avail able 1,3,5‐trimethoxybenzene (10). The methylated kaempferols 2–5 were also pre pared by use of this concise synthetic methodology. The key transformations in this synthesis involved the I2 oxidative‐promoting‐cyclization and DDO oxidative hydroxylation. Several strategies to achieve 1 are provided.
Solvent Effects on Aza‐anionic Cycloaromatization of 2‐(2‐Substituted‐ethynyl)benzonitriles
Authors: Lin Chi‐Fong , Yang Jia‐Huei , Hsieh Pei‐Chen , Lu Wen‐Der , Wu Ming‐Jung
Published: May 2015

The methanolysis of 2‐(2‐aryl ethynyl)benzonitriles is accelerated when the polar aprotic solvents are added, which could enhance the 6‐endo pathway and give isoquinolones, though the 5‐exo pathway is occupied mostly. The yields of products would also be in creased.
Recent Results from the Tokyo‐EBIT
Authors: Ohtani Shunsuke
Published: May 2015

A number of different experiments are progressing in parallel for the study of the physics of highly charged ions using the Tokyo‐EBIT. This paper gives the general feature of the apparatus and surveys some recent works per formed with it.
Laser Spectroscopic Studies of Transition Metal Containing Radicals
Authors: Cheung Allan S‐C.
Published: May 2015

Our recent work on the spectroscopic studies of diatomic transition metal radicals is briefly presented. Various experimental methods to produce transition metal radicals and obtain electronic spectra using laser spectroscopic techniques are reviewed. Our latest results on the A 2Π‐X2Σ+transition of TiN using polarization spectroscopy and the C 4Σ‐X 4Σ− transition of VS using laser induced fluorescence spectroscopy are described and preliminary results on these transitions are reported.
Laser Induced Atomic Coherence and Interference in Cold Atoms
Authors: Yan Min , Rickey Edward G. , Zhu Yifu
Published: May 2015

We report experimental studies of electro magnetically induced transparency and enhancement of third‐order optical nonlinearities in A‐type atomic systems realized in 87Rb atoms cooled and confined in a magneto‐optical trap. We observed complete transparency of a weak probe laser in the A type Rb system with a moderate coupling field. With a third pump laser tuned to a fourth atomic state, the atomic system exhibits the interference‐enhanced third‐order susceptibility and only absorbs two photons, but not one photon. Our experiment demonstrates large nonlinear absorption of the weak probe laser, from which greatly enhanced Kerr nonlinearity in the Rb system is inferred.
Deconvolution of Atomic Photoabsorption Spectra: A Match between Theory and Experiment
Authors: Chang Tu‐Nan , Luo Yuxiang , Fung Hok‐Sum , Yih Tai‐Sone
Published: May 2015

We present in this paper an extension of a recently proposed deconvolution procedure to compare directly the theoretical and experimental spectrum of a doubly excited ultra‐narrow and nearly symmetric resonance in atomic photoabsorption. Our discussion is based on a set of analytical relations in terms of the variations of i) the ratio between the resonance width ¡ and the experimental energy resolution ‐ in the limit when ¡i =‐ ¿ 1 and ii) the column density nl of the media in a photoabsorption experiment.
Angular Momentum Effects in Excited Atoms
Authors: Williams Jim , Yu Dehong
Published: May 2015

Spin‐orbit and electron exchange effects may be identified separately through the observation of “integrated” Stokes parameters of the radiation from excited states after impact by spin‐polarized electrons. The principles underpinning the measurements and the techniques are described. Stokes parameters within 2.5 eV of thresh old are discussed for selected excited states of inert gas atoms. The combined effects of electron exchange and the internal spin‐orbit inter action play a significant role in the excitations of the J = 1 and 2 intermediately‐coupled states while electron exchange is the mechanism for the excitation of the J = 3 well LS‐coupled states.
Elastic Electron‐molecule Scattering Cross Sections: Sulphur Hexafluoride and Benzene
Authors: Cho Hyuck , Gulley Robert J. , Buckman Stephen J.
Published: May 2015

Absolute differential cross sections for elastic scattering of electrons from two non‐polar molecules with high polarizabilities, sulphur hexafluoride (SF6) and benzene (C6H6) have been measured: SF6 at 11 incident energies between 2.7 and 75 eV and scattering angles between 10° and 180° and C6H6 at 13 incident energies between 1.1 and 40 eV and scattering angles between 10° and 130°. The magnetic angle‐changing device, based on that of Read and co‐workers, has been used to extend the SF6 measurements to backward angles (130° to 180°) for incident energies below 15 eV. Some features of these measurements, including the agreement with contemporary scattering theory, are reviewed.
The Approach to Asymptotic Behavior in Photoionization
Authors: Pratt Richard H. , Surić Tihomir
Published: May 2015

The high energy behavior of many atomic processes can be understood in terms of the theory of asymptotic Fourier transforms (AFT). In high energy atomic processes initial or final state wave functions will include continuum states of asymptotic plane wave character, and these will often result in a matrix element which can be viewed as a (multi‐dimensional) Fourier transform. The result will be a behavior of matrix elements and cross sections as inverse powers of the asymptotic momenta, associated with singular behaviors of atomic wave functions, which in turn are associated with the singular (Coulomb) behavior of the interaction of the atomic constituents. The situation is complicated by the Coulomb functions which modify these plane wave behaviors; these result in slowly convergent factors (we call them Stobbe factors) which may be explicitly factored out, yielding a matrix element as a product of a Stobbe factor and a residual matrix element which converges rapidly to its asymptotic form. We will illustrate these ideas here in a discussion of single and double non‐relativistic photoionization, though the approach may also be applied to electron scattering (and with excitation or ionization) and in the relativistic case. The main ideas of the approach can already be illustrated in the discussion of ionization of a particle in a central potential. Within this approach we explain both (for single ionization) the persistent high energy deviations from independent particle approximation predictions and (for double ionization) the shake–off and quasi–free contributions. We also discuss the importance of final state interactions and retardation corrections.
Van‐Der‐Waals Vibrations of Aromatic‐Argon Cations Studied by ZEKE Electron Spectroscopy
Authors: Kimura Katsumi
Published: May 2015

This article is to review ‘van der Waals (vdW) vibrations’ which have been observed for many kinds of aromatic‐argon vdW complexes produced in supersonic jets. The main characteristics of zero‐kinetic‐energy (ZEKE) electron spectroscopy for studying vdW complexes are also described briefly. For the aromatic‐argon vdW complexes so far studied, it is pointed out that the stretching mode is in a range of 40–60 cm−1, and the bending mode is in a range of 10–40 cm−1.
Chemical Bonding in Hydrogen Molecular Ion and Competition between Laser‐induced Ionization and Dissociation
Authors: Yuan Jian‐Min , Duan Yiwu , Liu Wing‐Ki
Published: May 2015

Just as a helium atom is a prototype for atoms, a hydrogen molecular ion is a prototype for chemical bonding in molecules. In the presence of an external field, the latter also serves as a prototype for which field‐induced ionization and dissociation compete with each other. Pauli was the first to examine the nature of chemical bonding in terms of the old quantum theory. In view of the recent developments of nonlinear dynamics and quantum chaos, we re‐examine the negative conclusion that he reached in his thesis. In particular, we are interested in finding out whether the classical three‐body system is stable and whether any part of the chemical bonding can be attributed to its classical stability. Our result shows that indeed classical phase space structures exist which contribute to chemical bonding, when quantized semiclassically. Thus chemical bonding is not a purely quantum phenomenon, as generally believed.

We also examine the classical dynamical behavior of this three‐body system in the presence of an external field beyond the Born‐Oppenheimer approximation. Interesting competition exists between ionization, dissociation, and Coulomb explosion. Although ionization dominates over dissociation at high laser fields, there exists a range of laser intensity below 150 TW/cm2 for which we can concentrate on dissociation alone without significant interference from the ionization process.
Preferential Oxygen‐Trapping in Metallic Multilayers: ASIMS Perspective
Authors: Sarkar Subhendu , Chakraborty Purushottam
Published: May 2015

The matrix effect in a secondary ion mass spectrometry (SIMS) depth profile can distinctly represent any change in the chemistry of surface or interface regions of thin films or multi layered structures. Present work shows how a preferential in corporation of oxygen in metallic multi layered structures has been manifested by such an analysis.
Independence of the Second‐Order Perturbed Total Energy on the Screening Charge
Authors: Cheng Wen‐Yu , Huang Keh‐Ning
Published: May 2015

The non‐relativistic total energy of a many‐electron atomic system up to the second order in the perturbation theory is proved to be in dependent of the choice of the screening charge in the unperturbed Hamiltonian with a central Coulombic potential. The ground‐state energy of a helium‐like ion is calculated as a demonstration.
The Host/Guest Type of Excited‐State Proton Transfer; a General Review
Authors: Chou Pi‐Tai
Published: May 2015

Contemporary progress regarding guest/host types of excited‐state double proton transfer has been reviewed, among which are the biprotonic transfer within doubly H‐bonded host/guest complexes, the transfer through a solvent bridge relay, the intramolecular double proton transfer and solvation dynamics coupled proton transfer. Of particular emphases are the photophysical and photochemical properties of excited‐state double proton transfer (ESDPT) in 7‐azaindole and its corresponding analogues. From the chemical aspect, two types of ESDPT reaction, namely the catalytic and non‐catalytic types of ESDPT, have been classified and reviewed separately. For the case of static host/guest hydrogen‐bonded complexes both hydrogen‐bonding strength and configuration (i.e. geometry) play key roles in accounting for the reaction dynamics. In addition to the dynamical concern, excited‐state thermodynamics are of importance to fine‐tune the proton transfer reaction in the non‐catalytic host/guest type of ESDPT. The mechanisms of protic solvent assisted ESDPT, depending on host molecules and proton‐transfer models, have been reviewed where the plausible resolution is deduced. Particular attention has been given to the excited‐state proton transfer dynamics in pure water, aiming at its future perspective in biological applications. Finally, the differentiation in mechanism between solvent diffusive reorganization and solvent relaxation to affect the host/guest ESPT dynamics is made and discussed in de tail.
Complexation Kinetics of N‐Alkyl‐Substituted Diamino Diamides with Nickel (II) in Aqueous Solution
Authors: Chao Min‐Shiun , Huang Shih‐Liang
Published: May 2015

Equilibrium constants are deter mined for the protonation and metal complexation of the nickel(II) complexes with 4‐methyl‐4,7‐diazadecanediamide (4‐Me‐L‐2,2,2), 4,7‐dimethyl‐4,7‐diazadecanediamide (4,7‐N,N′‐Me2‐L‐2,2,2), 4‐ethyl‐4,7‐diazadecanediamide (4‐Et‐L‐2,2,2), and 4‐methyl‐4,8‐ diazaundecane diamide (4‐Me‐L‐2,3,2), in 0.10 M KCl at 25.0°C. The formation kinetics of these nickel (II) complexes have been studied under the same conditions with use of the stopped‐flow technique. The possible path ways for the complexation reaction of nickel (II) with these ligands are discussed. The first metal‐nitrogen bond formation is proposed as the rate‐determining step for the reactions of nickel (II) with the unprotonated ligands; proton loss is the rate‐limiting step in the reactions of nickel (II) with the monoprotonated ligands. Similarly, in dissociation reactions of these nickel (II) complexes, the rate‐determining step for the water dissociation pathway is the break age of the second nickel‐nitrogen bond; the rate‐determining step for the proton‐assisted path way is the protonation of the released amino group. The important factors determining the reactivity of these complexes are considered. The kinetic results of the formation and dissociation reactions of these complexes are consistent with dissociative mechanism.
The HPLC Resolution of Nucleic‐Acid Bases and An a Log Hypoxanthine on R,S‐2‐Hydroxypropyl Derivatized β‐Cyclodextrin Bonded Chiral Stationary Phase Using a Water‐Based Mobile Phase
Authors: Chen Shushi
Published: May 2015

A HPLC approach using R,S‐2‐hydroxypropyl derivatized β‐cyclodextrin packed column as the stationary phase was developed to resolve five nucleic‐acid bases and an a log hypoxanthine in the reversed‐phase mode. These bases are not only similar in structure but also very close in basicity. However, the resolution can be completed in less than ten minutes and is considered to be better carried out on the R,S‐2‐hydroxypropyl derivatized β‐cyclodextrin phase than that obtained on the native β‐cyclodextrin phase under the same chromatographic conditions. The mechanism involved in the resolution is believed to be inclusion complexation between the analyte and the cavity of cyclodextrin in the reversed‐phase mode. The retention time was found relevant to the size of the analyte. The number of groups on analyte that is available to form hydrogen bonding with hydroxyl groups on CDs also affects the retention scale. Factors of introducing organic acid and base or organic modifier such as methanol to the water‐based mobile phase or increasing their percent ages in the mobile phase decreases the retention time without de grading the resolution significantly.
The Syntheses of 4‐Arylamino‐1,2,3‐Triazoles and Stable 6‐Sydnonyl Verdazyls from Sydnone Derivatives and Their Fragments
Authors: Kuo Wen‐Fa , Lin I‐Tzu , Sun Shiaw‐Wen , Yeh Mou‐Yung
Published: May 2015

α‐Chloroformylarylhydrazones 1 and α‐chloroformylarylhydrazones of sydnonecarbaldehydes 3 have been prepared by a new synthetic route: α‐chloroformylarylhydrazines hydrochlorides 2 reacted with corresponding carbonyl compounds. Reactions of compounds 3 with various hydrazines to give 6‐sydnonyl‐1,2,4,5‐tetrazinan‐3‐ones 7 and/or carbazones 8 were also investigated. By oxidization with lead dioxide, compounds 7 were trans formed to stable 6‐sydnonyl‐3,4‐dihydro‐3‐oxo‐1,2,4,5‐tetrazin‐1(2H)‐yl radical derivatives 9 (sydnonyl verdazyls). Furthermore, sydnonecarbaldehydes arylhydrazones 5 through acidic conditions could be transferred to 4‐arylamino‐1,2,3‐triazoles 6 which were also obtained by means of acidic decompositions of 4‐formylsydnones 10.
The Synthesis of Some New 7‐Methyl‐3‐substituted‐1,2,4‐triazolo[3,4‐b]benzothiazoles
Authors: Dong Heng‐Shan , Zhang Ji‐Yong , Tang Yan‐Bo , Mao Xue‐Rong , Quan Bin
Published: May 2015

New 7‐Methyl‐3‐substituted‐1,2,4‐triazolo[3,4‐b]benzothiazoles were synthesized from p‐methylaniline to 5 with various aromatic carbonic acids. The yielded product 6a‐j was investigated with Elemental analyses, NMR, MS and IR techniques.
Syntheses of 5‐Hexadecanolide, 6‐Acetoxy‐5‐hexadecanolide and Tanikolide
Authors: Chang Meng‐Yang , Lin Chien‐Lun , Chen Shui‐Tein
Published: May 2015

Total syntheses of 5‐hexadecanolide (1), 6‐acetoxy‐5‐hexadecanolide (2) and tanikolide (3) are described. 1‐Bromoundecane (4) and 5‐benzyl‐1‐pentanal (5) were chosen as starting materials. Wittig olefination and Grignard addition 4 and 5 afforded the 16‐carbon skeleton, which under went a series of functional group transformations to give δ‐lactonederivatives 1, 2 and 3.
Preparations of Tris(Triphenylphospnine)copper and Tris(triphenylphosphine)silver Complexes of Phenalenone, Diphenylcyclopropenone and Tropone
Authors: Chen Yen‐Hsien , Lin Ching‐Cheng , Lin See
Published: May 2015

The tris(triphenylphosphine)copper and tris(triphenylphosphine)silver complexes of phenalenone 4, diphenylcyclopropenone 5 and tropone 6 were prepared by treating tris(triphenylphosphine)copper tetrafloroborate 2 and tris(triphenylphosphine)silver tetrafluoroborate 3 with basic ketones 4, 5 and 6 in high yields. All these complexes are stable in either air or moisture, and soluble in common organic solvents such as dichloromethane and chloroform.
Corrosion Behavior of Aluminum in Non‐Uniform Electric Fields
Authors: Dobrewsky Ivan , Sabeva Emilia , Petkova Nedialka
Published: May 2015

The present paper discusses the effect of the geometrical structure of the electric fieldon the corrosion of aluminum cathodes by electrolysis of aqueous solutions of sodium chloride. A correlation between the mass of the aluminum dissolved from the cathode and the factors electric current density, distance between the electrodes, electrolysis time and sodium chloride concentration by electrolysis with direct current in electric fields of various geometries was found.
Studies on the Mass Spectra of N‐Aryl α,β‐Unsaturated γ‐Lactams
Authors: Wang Eng‐Chi , Huang Keng‐Shiang , Lin Kuo‐Fan , Chen Jan‐Cheng
Published: May 2015

The mass spectra of a series of N‐aryl α,β‐unsaturated γ‐lactams were studied. Besides the molecular ion, the three characteristic fragments such as [M+‐29], [M+‐55], and [M+‐82] were commonly found in a series of N‐Aryl α,β‐unsaturated γ‐lactams in EI/MS. Further more the mechanism for the interpretation of these fragments is also de scribed.
Synthesis of Elvirol Methyl Ether
Authors: Ho Tse‐Lok , Ho Meng‐Fen
Published: May 2015

Elvirol methyl ether has been synthesized from p‐cresol via 2‐(2‐cyclopentenyl)‐4‐methylphenyl methyl ether by ozonolysis, dithioacetalization, reduction, and Wittig reaction. The over all yield was 18.8%.
Synthesis of Iridoid Monoterpenes and Prostaglandins, via Photochemical Rearrangement of Bicyclo[2.2.1]hept‐5‐en‐2‐One
Authors: Tai Huo‐Mu , Yang Chau‐Chen , Yeh Min‐Ling , Chang Nein‐Chen
Published: May 2015

The synthesis of cyclopentanoid natural products, iridoid monoterpenes and prostaglandins, was achieved from a common intermediate 2, which was obtained from 1 via photochemical rearrangement.
Synthesis of the Chiral Pair of a Novel Thromboxane Antagonist, 3‐[2‐(3‐Benzenesulfonylamino‐7‐oxabicyclo[2.2.1]hept‐2‐yl‐methyl)phenyl] Propionic Acid
Authors: Chern Ching‐Yuh , Yek Yung Lee , Jan Ja‐Ding , Kan Wai Ming
Published: May 2015

Preparation of the enantiomeric pair of 3‐[2‐(3‐benzenesulfonylamino‐7‐oxabicyclo[2.2.1]hept‐2‐yl‐methyl)phenyl] propionic acid, a novel thromboxane antagonist is reported. They are synthesized from either enantiomers of known (1R,2R,3R,4S)‐3‐[2‐(3‐carboxy‐7‐oxabicyclo[2,2,1]hept‐2‐yl‐methyl)phenyl]‐propionic acid methyl ester via epimerization, modified Curtius' rearrangement and sulfonylamino formation. Other derivatives may be prepared similarly.
Synthesis of Nitrated Analogs of Distamycin and their DNA Cleaving and Protecting Activities under UV Irradiation
Authors: Xiao Junhua , Yuarf Gu , Huang Weiqiang , Lum John H. K. , Lee K‐L Daniel , Chan Albert S. C.
Published: May 2015

Two nitrated analogs of distamycin were synthesized by a novel haloform reaction and the DCC/HOBT coupling reaction in a convenient and effective way with out amino group protection. Our results have demonstrated that these polyamides show DNA cleaving activity under long UV (LUV 365 nm) irradiation. Furthermore, it is an unexpected discovery that these analogs can prevent DNA dam age under short UV (SUV 302 nm).
A New Sesquiterpene, α‐Santalane‐11,12,13‐Triol from the Root Bark of Severinia Buxifolia in Hainan
Authors: Cherf Chien‐Mao , Lin Fu‐Wen , Kuo Ping‐Chung , Shi Li‐Shian , Wang Jhi‐Joung , Wu Tian‐Shung
Published: May 2015

Anew sesquiterpenoid, α‐santalane‐11,12,13‐triol, together with thirty known compounds were isolated and characterized from the root bark of Severinia buxifolia in Hainan. Their structures were determined by spectroscopic methods. The relationship between constituents and collecting area is also discussed.
On Structural Parameterization and Molecular Modeling of Peptide Analogues by Molecular Electronegativity Edge Vector (VMEE): Estimation and Prediction for Biological Activity of Dipeptides
Authors: Li Shengshi Zhiliang , Fu Bianhong , Wang Yuanqiang , Liu Shushen
Published: May 2015

Based on the distance between atoms and the electro‐negativity of each atom, a new set of descriptors called the molecular electronegativity edge vector (VMEE) being applied to de scribe the molecular structure of peptide analogues, is proposed only from the primary structure of peptides. Here several quantitative structure activity relationship models are proposed on the biological activity of 58 angiotensin converting enzyme (ACE) inhibitors and of 47 bitter tasting dipeptides by multiple linear regression method. The results show that the novel molecular electronegativity edge vector (VMEE) has both excellent structural selectivity and good activity estimation. Besides, this novel molecular electronegative edge vector, be cause it is easy to calculate, will be useful in structure characterization and activity prediction of biological molecules.
Synthesis of Thymidine Dimer Containing Novel (N‐Acetyl)imino Linkage
Authors: Yang Te‐Fang , Chien Fang‐Chi , Chung Fen‐Yu
Published: May 2015

By starting with 3′‐keto‐5′‐O‐protected thymidine, 3′‐O‐amino‐5′‐t‐butyl‐diphenylsilyl thymidine (9) was prepared and coupled with 3′‐O‐t‐butyl‐diphenylsilyl‐5′‐formyl thymidine to form a nucleoside dimer (11) containing oxime linkage. The back bone of this dimer, then, under went reduction followed by acetylation to give an (N‐acetyl)imino linkage, and a novel dinucleotide (13) was obtained.
Application of Laser‐Enhanced Ionization Spectroscopy: Effect of Dissociation Constant on the Atomization Efficiency Determination in an Acetylene‐Air Flame
Authors: Ke Ching‐Bin , Lu Shme‐Ing , Lin King‐Chuen
Published: May 2015

By using laser‐enhanced ionization (LEI) technique, we have studied atomization efficiencies of the alkalihalides in an acetylene/air flame. As an aqueous solution of the metal salt was nebulized into the burner head, a flame with a high temperature of about 2500 K may cause dissociation of the ionic bond to release the free metal atoms. The ratio of the number density of free metal atoms present in the flame to the total number density of the same metal element nebulized determines the atomization efficiency. In this work, binary salt solutions including LiX, NaX, and KX (X=Cl, Br, and I) were used; each was prepared at 5 ppm (μg/mL) metal concentration. The atomization efficiency of the metal element was measured, as the accompanied halogen species was varied. We found that the ratios of atomization efficiencies of the akalielement in different halide compounds were almost equal to one. Atomization efficiency determination is dominated by the metal atom, but weakly influenced by the binding halogen species. The observation may be interpreted satisfactorily by using the Sugden‐Bulewicz model. Based on this model, the metal atomization efficiency for different halide compounds depends on the number densities of the halogen atoms and the related dissociation constants. For the binary salt with a small concentration and a large dissociation constant, the atomization efficiency determination tends to be dominated by the metal atom alone.
Solvolysis of 1‐tert‐Butyl‐1‐(4‐phenoxyphenyl) Methyl Bromide and Chloride. Further Example for Possible Contribution of Non‐canonical Resonance Structure in the Transition State
Authors: Liu Kwang‐Ting , Chuang Chih‐Shiow
Published: May 2015

The solvolysis of 1‐tert‐butyl‐1‐(4‐phenoxy)methyl bromide (5b) and chloride (5c) in a variety of solvents were carried out. Limiting SN 1 mechanisms were suggested from the observation of linear relation ships using single‐parameter Winstein‐Grunwald type correlation between logarithm of rate constants with YxBnBr and YxBnCl scales, respectively. This result indicated positive charge delocalization over both arylrings and provided further evidence for possible contribution of non‐canonical resonance structure in the cationic transition state.
On Polarizability Effect of Alkyl Substituent
Authors: Li Shengshi Zhiliang , Yuan Xiaoyan , Wang Yuanqiang , Cao Chenzhong , Liu Shushen
Published: May 2015

The relative polarizability effect of alkyl substituent can be conveniently obtained by calculating the so‐called Polarizability Effect Index (PEI) value, pro posed firstly in our laboratories, PEI = Σ (α/Ni2), where ai is the polarizability of primary units CH3, CH2‐, CH< and >C‐, and the Ni is the carbon atom number from reaction site to the primary unit. By using the PEI and atomic charge in a molecule, the ionization potential of alkyl halide, the enthalpy of reaction for the gas‐phase addition of a proton to an alcohol or ether (proton affinity), the gas‐phase basicity of alcohols or ethers (proton affinity), and gas‐phase acidity of alcohols can be quantitatively modeled by the two‐parameter expression equation.
Microfabricated Electrophoresis Chips on Quartz Substrates and Their Applications on DNA Analysis
Authors: Lee Gwo‐Bin , Chen Shu‐Hui , Lin Chin‐She , Huang Guan‐Ruey , Lin Yen‐Heng
Published: May 2015

Design and fabrication of microcapillary electrophoresis (CE) chips on quartz substrates are described. The micro capillary channels are formed by the combination of a metal etch mask and wet chemical etching. In this paper, a simple but reliable one‐mask process is applied to fabricate micro structures on quartz substrates, which are commercially‐available blank photomasks. The selection of the quartz substrates greatly simplifies the fabrication process. The substrates with micro channels are then bonded with an other quartz cover plate at low temperature by using diluted hydrofluoric acid (HF) solution. Good channel sealing is observed. The low temperature bonding yields low residual stress and makes chemical surface modification prior to bonding feasible, if necessary. The quartz chips with higher UV transmittance allow us to use a laser induced fluorescence detection system for chemical analysis successfully. Solutions containing Nile blue are first per formed in the CE chips as a demonstration of electrophoretic injection. The capability of the microfabricated CE chips for electrophoretic injection and separation is then characterized via the analysis of DNA fragments φX174 digested by Hae III. An excellent signal/noise ratio is obtained. In addition to single‐channel sample injection and separation, multi‐channel de vices capable of parallel electro‐migration of multi‐samples have also been demonstrated in the study.
Cycloaddition of α‐Chloroformylarylhydrazines' with Pyridines Afford 2‐Aryl‐2H‐[1,2,4]triazolo[4,3‐a]pyridin‐3‐Ones
Authors: Chiu Chun‐Yen , Kuo Chao‐Nan , Kuo Wen‐Fa , Yeh Mou‐Yung
Published: May 2015

2‐Aryl‐2H‐[1,2,4]triazolo[4,3‐a]pyridin‐3‐ones 4 were synthesized by cycloaddition of α‐chloroformylarylhydrazines 7 with pyridines 1. The inductive and mesomeric effects of substituents on pyridines were also investigated in this study. In reactions of 3‐substituted pyridines bearing a π‐electron‐donating substituent, the ortho site, C(2), of the pyridine ring is more favored for cycloaddition than the para site, C(6). As the substituent is a σ‐electron‐donating group, the cycloaddition only occurs on the ortho position. For reactions of 2‐substituted pyridines, however, cycloadditions were controlled solely by inductive effect, regard less of mesomeric effect. Only when the substituent is an electron‐donating group, would the cycloaddition proceed to afford expected cycloadducts. Further more, it is found that the inductive effect plays a more important role than the steric effect for reactions using 2‐substituted pyridines.
Fusicoccane Diterpenoids and Bisbibenzyls from the Liverwort Plagiochila Peculiaris
Authors: Wu Chia‐Li , Liou Chuang‐Shing , Ean Uni‐Juni
Published: May 2015

Two new oxygenated diterpenes, fusicoccanin and neofusicoccantriepoxide, were isolated and identified from the Taiwanese liver wort Plagiochila peculiaris. The latter compound possesses a methyl‐rearranged fusicoccane skeleton. In addition, known secoaromadendranes and macrocyclic chloro‐bisbibenzyls were also isolated from the polar fraction. P. peculiaris rep resents a very complex chemo‐type of this genus.
Annocherine C, A New C‐α Hydroxy Benzylisoquinoline and Other Constituents from the Leaves of Annona Cherimola
Authors: Chen Chung‐Yi , Wu Yang‐Chang
Published: May 2015

A new C‐α hydroxy benzylisoquinoline, annocherine C (1), along with nine teen compounds including six alkaloids, liriodenine (2), oxoxylopine (3), oxonantenine (4), (‐)‐asimilobine (5), (‐)‐xylopine (6) and (‐)‐anolobine (7); four steroids, β‐sitosterol, stigmasterol, β‐sitosteryl‐D‐glucoside and stigmasteryl‐D‐glucoside and nine benzenoids, methylparabene, vanillin, trans‐methyl p‐coumarate, cis ‐methyl p‐coumarate, p‐hydroxybenzadehyde, p‐hydroxybenzoic acid, 4‐methoxybenzoic acid methylester, methyl vanillate and p‐dihydrocoumaric acid, were isolated from the leaves of Annona cherimola. These compounds were identified by spectral analysis.
Simple Fourier Trans form(FT)‐IR and Reverse‐Phase HPLC Identification Methods of Commercial Ganoderma Products
Authors: Chen Deng‐Hai , Ju Huei‐Yen , Hseu Kuo‐Chong
Published: May 2015

Ganoderma products could be classified into 3 types according to their raw materials, i.e. fruit bodies, cultured mycelia and the mixtures of both. Seven commercial samples and three mycelia products prepared in laboratory were analyzed by Fourier Trans form(FT)‐IR spectrophotometer. The fruit‐body products gave a weak absorption band at 890∼894 cm−1 and the mycelia show a weak to medium band at 774∼778 cm−1 on the FT‐IR spectra, respectively. These two bands were observed in the IR spectra of mixed‐type products. A modified sample pretreatment procedure for the reverse‐phase HPLC analysis was also investigated. The spectral patterns revealed that fruit bodies of the commercial samples were the species of G. tsugae.
Reactions of Bis[Diphenyl‐3‐(4‐Methoxyphenylsydnonyl)]Phosphine Palladium Chloride and Phosphorus Ligands and Crystal Analysis of Its Phosphite Adduct
Authors: Lin S. T. , Peng K. J. , Hung T. F. , Tien H. J.
Published: May 2015

Reactions of bis[diphenyl‐3‐(4‐methoxyphenylsydnonyl)]phosphine palladium chloride and phosphines or phosphites were performed yielding cis‐dichloropalladium complexes. Complexes have been characterized by spectroscopic techniques (compounds 5–13) and by X‐ray diffraction for compound 5. Bond lengths of P‐C(10) and P‐C(16) de creased more than that of P‐C(s) after complex formation suggesting that the phenyl rings were able to contribute more electron density to phosphorus for binding with Pd(II) than the sydnone ring does. The equilibrium constants and rate constants for the reaction between complex 4 and phosphorus ligands depend not only on the basicity but also on steric size (i.e., cone angle) of phosphorus ligands used.
Synthesis and Spectral Properties of Phenyl‐Pyridin‐2‐Ylmethylene‐Amine Complex of Rhodium(III)
Authors: Lee Jen Rong , Lung Jin Wang , Huang Wen Liang
Published: May 2015

A new complex of [Rh(PA)2Cl2]Cl·H2O (where PA = phenyl‐pyridin‐2‐ylmethylene‐amine) has been synthesized and characterized. The complex shows high intensity bands in the UV region, and these are assigned to spin‐allowed π‐π* transitions. The medium‐intensity absorption band profile in the lower energy region can be explained by convolution of spin‐allowed CT and d‐d* transitions. Emission spectrum at low temperature (77 K) of the complex in EtOH/MeOH (4:1 v/v) has also been investigated. It shows a broad, symmetric, and structureless red emission with micro second life time and hence is assigned as d‐d* phosphorescence. Voltammetric data have also been obtained for the complex. There were three reduction peaks observed for the complex. The first peak, including two reduction steps with elimination of two chlorides, is consistent with ECEC reaction.
Langmuir Aggregation of Stain on Ionic Surfactant and its Application: Interaction of Bromo‐Pyrogallol Red with Cetyl Trimethylammonium Bromide (CTAB) and Determination of Molybdenum Traces
Authors: Gao Hong‐Wen
Published: May 2015

The microphase adsorption‐spectral correction (MPASC) technique was de scribed and applied to study the interaction of bromo‐pyrogallol red (BPR) with cetyl trimethylammonium bromide (CTAB). The synergism mechanism of micelles was analyzed and discussed. The large electrostatic micelle adsorbs the chromophore in only the monolayer, and the adsorption obeys the Langmuir adsorption. The formation of the (BPR2·CTAB)78 aggregate accelerates the Mo‐BPR complex reaction. Experimental results showed the adsorption constant of the adsorption aggregate 6.20 × 105 and its molar absorptivity ϵr610nm = 1.40 × 106 lmol−1cm−1. For analysis of samples, the recovery of Mo was between 97.4 and 107% and the RSD was less than 4.39%.
Fe(phen)32+‐Modified Zeolite Particles and Their Energetic Studies
Authors: Liou Yea Wenn , Wang Chong Mou
Published: May 2015

Chemically modified zeolite Y (NaY) particles and their resulting modified electrodes were prepared with acridinium (AcH+), iron(II) and 1,10‐phenanthroline (phen) for energetic studies. According to diffuse reflectance absorption spectroscopy and cyclic voltammetry, AcH+ and Fe(phen)32+ were successfully entrapped in the zeolite particles. Transient emission spectra measurements showed that the life time of AcH+* in the zeolite particles (to 35 ns; λex 365 nm; λem 500 nm) was greatly reduced upon incorporating Fe(phen)32+ and Fe2+. The fast de cay of AcH+*(NaY) suggested that a reductive quench was likely to take place in the zeolite particle. Probably due to a size‐exclusion effect, the bulky electron donor, N, N‐diethyl‐2‐methyl‐1,4‐phenylenediamine (DEPD), revealed a difficulty in reaching the photosensitizer, AcH+, in side the zeolite particle. As a consequence, the in significant photocurrent for the oxidation of DEPD was from the NaY|AcH+ electrode. However, if Fe2+ and Fe(phen)32+ were incorporated, the photocurrent would become more significant. Closer examinations, in addition, showed that the photooxidaton of DEPD occurred more rapidly on the NaY|AcH+|Fe(phen)32+ electrode, compared to the NaY|AcH+|Fe2+ electrode. This difference apparently results from a greater gap in energetics between DEPD and Fe(phen)33+(NaY) than that between DEPD and Fe3+(NaY). Due to this effect, a greater amount of indophenol blue, derived from the coupling reaction of the oxidized DEPD with 1‐naphthol, was formed and de posited on the NaY|AcH+|Fe(phen)32+modified electrode. Thanks to this photo‐induced charge‐transfer reaction, the NaY|AcH+|Fe(phen)32+ particle showed an application potential in image recording.
Reclamation of Used Engine Oil
Authors: Ishaq Mohammad , Iqbal Yousaf , Ahmad Imtiaz , Khan Waqar
Published: May 2015

Used lubricating oil from vehicles was treated with various types of chemicals to be regenerated. It was found that used lubricating oil could be reclaimed with sulphuric acid, sodium hydroxide, sodium phosphate, ammonium sulphate and rosin. Viscosity and pour point of the reclaimed lubricating oil were improved with the additive methyl methacrylate. The reclaimed lubricating oil was characterized by four‐ball ma chine and it was found that wear scar diameter (WSD) has greatly been de creased with the reclamation. The results of atomic absorption spectrophotometer also show that wear metals have also been de creased to an appreciable amount in there claimed lubricating oil.
Non‐Alkaloidal Constituents from the Stem of Ficus Septica
Authors: Kuo Ping‐Chung , Chm Chao‐Chen , Shi Li‐Shian , Li Chia‐Ying , Wu Shwu‐Jen , Damu A. G. , Wu Pei‐Lin , Kuoh Chang‐Sheng , Wu Tian‐Shung
Published: May 2015

Seven triterpenes, two lignans, and twelve other known compounds were isolated from the non‐alkaloidal fractions of the stem of Ficus septica Among these triterpenoids, a rare triterpene skeleton derivative, 13,27‐cycloursan‐3β‐ylacetate was isolated from natural sources for the first time. All the structures of these compounds were elucidated by spectroscopic methods.
Immobilized Lipase PS‐C Catalyzed Resolution of Racemic Aromas by Transesterification
Authors: Jagtap Dhananjay V. , Shukla Manojkumar R. , Salunkhe Manikrao M.
Published: May 2015

Pseudomonas cepacia lipase immobilized on ceramic particles (PS‐C) enantioselectively acylate racemic aroma alcohols with vinyl acetate inorganic solvent. It is observed that laevo isomer under goes enzymatic transesterification enantioselectively.
Bulk Polymerization of Styrene and 4‐Methylstyrene with Cp*Ti(OBu)3/MAO/TIBA Catalyst
Authors: Hong J.‐L. , Chen Y.‐P.
Published: May 2015

Copolymerization of different amounts of styrene (St) and 4‐methylstyrene (MSt) using Cp*Ti(OBu)3/MAO/TIBA catalyst was performed in bulk state under hydrogen atmosphere. With out the participation of a reaction solvent, polymerization proceeded well with better yield as compared to those with toluene or cyclohexane as reaction solvent. The sharp peaks in the 13C NMR spectra indicate that both the St and MSt units in the copolymers are co‐syndiotactic in nature. The reactivity ratio evaluated from a Fineman‐Ross plot suggests a better reactivity of MSt than St monomers. Experiments also indicate that the decrease of Mn and Mw, and the broadening of molecular weight distribution were accompanied by the higher hydrogen pressure employed in the polymerization stage, a result attributed to the chain transfer reaction promoted by the hydrogen gas.
Extractive Determination of Vanadium in Fungi Samples
Authors: Kamavisdar Anand , Khanwalkar Shitikanth R. , Patel Rajmani
Published: May 2015

A new reagent system has been reported for the extractive separation and simultaneous spectrophotometric de termination of vanadium (V). The method is based on the formation of a water in soluble blue‐violet V(V) complex with N‐hydroxy‐N‐m‐tolyl‐N′‐phenylbenzamidine (HTPBA), and neutral surfactant Triton X‐100 into chloroform over an acidity range of 1.0–10.0 M acetic acid. The complex shows a broad absorption maximum at 570 nm, when measured against a chloroform blank. The λmax (570 nm) of the complex and that of re agent (313 nm) are well separated, hence the excess of the reagent does not interfere in the spectrophotometric de termination of the metal. The molar absorptivity (ϵ) of the complex is (4.74) × 103 1 mol−1 cm−1. The linearity of the calibration curve is followed between 0.5–12.0 μg mL−1 with slope, intercept and correlation coefficient of 9.16× 10−2, 4.5 × 10−3 and 0.999, respectively. The detection limit of the method is 45 μgl−1. The proposed re agent system provides significantly higher tolerance limit for iron (500 μg mL−1) and also various metalions commonly associated with vanadium did not interfere. The method was applied for the deter mi nation of vanadium content of three samples i.e. Spirogyra, Puccinia and Riccia.
On‐Line Determination of Arsenic Species in Sea Water by Selective Hydride Generation Coupled with Inductively Coupled Plasma — Mass Spectrometry
Authors: Den Su‐Jane , Wei Wen‐Chmg , Mierzwa Jerzy , Yang Mo‐Hsiung
Published: May 2015

A method for direct de termination of total in organic arsenic (III+V), arsenic (III) and dimethylarsinate (DMA) in sea water was developed by combining continuous‐flow selective hydride generation and inductively coupled plasma mass spectrometry (ICP‐MS) is presented. The principle underlying selective hydride generation is based on proper control of the reaction conditions for achieving separation of the respective arsenic species. The effects of pH and composition of reaction media on mutual interference between the arsenic species were investigated in detail. The results indicate that the appropriate media for the selective determination of total in organic arsenic, DMA and As(III) are 6 M HNO3, acetate buffer at pH = 4.63 and citrate buffer at pH = 6.54, respectively. The concentrations of total inorganic arsenic species, As(III+V), and As(III) were respectively deter mined and that of As(V) was obtained by the difference between them. As to the concentration of DMA, it was obtained after correction from the interference caused by As(III) and As(V). By following the established procedure, the detection lim its (as based on 3‐sigma criterion) for As(III+V), As(III) and DMA were 0.050, 0.009, and 0.002 ng/mL, respectively. There liability of the pro posed method was evaluated in terms of precision and spike addition. The results indicated that the precision of better than 3% and spike recovery of 95 to 105% for all the arsenic species tested in the natural sea water samples can be obtained.
A Simple and Efficient Method for the Synthesis of α,β‐Unsaturated Acyl Azo Compounds with NaNO2‐Acetic Anhydride Under Mild Conditions
Authors: Li Xiao‐Chuan , Wang Yu‐Lu , Wang Jin‐Ye
Published: May 2015

In this paper, eight aryl substituted α, β‐unsaturated acyl hydrazides undergo efficient oxidation to α,β‐unsaturated acyl azo compounds using NaNO2‐acetic anhydride under mild conditions with excellent yields.
Kinetics of the Reaction between Aromatic Aldehydes and 1,5‐Diamino‐4,8‐Dihydroxypyridazino[4,5‐d]Pyridazine
Authors: Medien H. A. A.
Published: May 2015

Kinetic studies were performed to investigate the mechanism of Schiff base formation in the reaction between aromatic aldehydes and 1,5‐diamino‐4,8‐dihydroxypyridazino[4,5‐d]pyridazine (DDPP). The studies were conducted at different temperatures with ethanol as solvent and acetic acid as catalyst. It is proposed that the first step involves the reaction of the aldehyde with a solvated proton (i.e. specific acid catalysis). Depending on the acidity of the medium, free or mono‐protonated (DDPP) at tacks the carbonyl group to form a carbinol‐amine inter mediate which then de hydrates to form the product. Plot of ΔH# versus ΔS# for the reaction gave a good straight line with isokinetic temperature of 343.15 K. Good linear relationship was obtained from the plot of log k against σ° values. The rate law derived from the proposed mechanism is in agreement with the experimental data and observations. The effects of meta and para substituents of benzaldehyde toward reactivity have been studied.
Recent Advances in Malaria Chemotherapy
Authors: Robert Anne , Dechy‐Cabaret Odile , Cazelles JÉRǑMe , Benoit‐Vical Françoise , Meunier Bernard
Published: May 2015

A short review of the currently used antimalarial drugs is reported. The molecular aspects of the different possible mechanisms of action of artemisinin is documented, including recent data on heme alkylation. The preparation and the in vitro antimalarial activity of new modular molecules named “trioxaquines” is also presented.
Preparation and Reactivity of Mo(NCMe)(η2‐C2Ph2)2(η4‐C4Ph4)
Authors: Chang Su‐Chin , Yeh Wen‐Yann , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

Reaction of Mo(CO)(η2‐C2Ph2)2(η4‐C4Ph4) and Me3NO in acetonitrile solvent affords Mo(NCMe)(η2‐C2Ph2)2(η4‐C4Ph4) 1. Compound 1 reacts with trimethylphosphine to produce Mo(PMe3)(η2‐C2Ph2)2(η4‐C4Ph4) 2, or reacts with diphenylacetylene to produce (η5‐C5Ph5)2Mo 3 and Mo(η2‐O2CPh)(η4‐C4Ph4H)(η4‐C4Ph4) 4. The molecular structures of 1, 2 and 4 have been determined by an X‐ray diffraction study.
Reaction Mechanisms of Strontium Ferrites Synthesis
Authors: Saleh Hesham Ibrahim
Published: May 2015

The reactions between strontium and iron nitrates have been studied in an open atmosphere system using three different molar ratios, 1:1 (I), 1:2 (II) and 2:1 (III) at different temperatures as pointed out from the DTA data. The reaction mechanism was discussed based on the chemical composition characterized by means of thermal analysis, X‐ray diffraction patterns, infrared spectra and magnetic susceptibility. It was found that the reaction products depend on both temperature of reaction and the ratio between reactants. The reaction products were found to be composed of a variety of iron compounds that possess different valences: SrFeO2.86, SrFeO2.97, SrFe2O4, SrFe12O19, Sr2Fe2O5 and Sr7Fe10O22 in addition to some accessory reaction products namely α‐Fe2O3 and FeO(OH).