bluuebunny/crossref_metadata_2025 huggingface dataset:
Flavonoid Glycosides from Terminalia catappa L.
Authors: Lin Yun‐Lian , Kuo Yueh‐Hsiung , Shiao Ming‐Shi , Chen Chien‐Chih , Ou Jun‐Chih
Published: May 2015

Under the inhibition of Cu+2‐induced LDL oxidation‐guided fractionation, two new flavone glycosides with galloyl substitution were isolated from the dried fallen leaves of Terminalia catappa L. Their structures were established as apigenin 6‐C‐(2″‐O‐galloyl)‐β‐D‐glucopyranoside (1) and apigenin 8‐C‐(2″‐O‐galloyl)‐β‐D‐glucopyranoside (2), together with four known flavone glycosides, isovitexin, vitexin, isoorientin, and rutin, on the basis of spectroscopic method. Compounds 1 and 2 showed significant antioxidative effects. Their IC50 were 2.1 and 4.5 μM, respectively.
Secoiridoids Glycosides from Some Selected Jasminum SPP
Authors: Shen Ya‐Ching , Chen Chih‐Fan , Gao Jianjun , Zhao Changqi , Chen Ching‐Yeu
Published: May 2015

Secoiridoid glycosides of three oleaceaous plants are described. Fractionation of the ethanolic extracts of Jasminum nitidum Skan, J. giraldii Diels and J. sambac (L.) Ait. var. trifoliatum Hort. (Oleaceace) resulted in the isolation of syringalactones A (1) and B (2), oleoside 7,11‐dimethyl ester (3), jasminoside (7), jaslanceosides B (8), sambacoside A (9) and molihuaside D (10). The structures of these secoiridoid glycosides were elucidated on the basis of spectral methods. Chemotaxonomy for plants of Jasminum is also discussed.
Structure‐Reactivity Relationships as Probes for the Inhibition Mechanism of Cholesterol Esterase by Aryl Carbamates. I. Steady‐State Kinetics
Authors: Lin Gialih , Lai Cheng‐Yue , Liao Wei‐Cheng , Kuo Bing‐Hong , Lu Chun‐Ping
Published: May 2015

For substituted phenyl‐N‐butyl carbamates (1) and 4‐nitrophenyl‐N‐substituted carbamates (2), linear relationships between values of NH proton chemical shift (δNH), pKa, and logk[OH] and Hammett substituent constant (σ) or Taft substituent constant (σ*) are observed. Carbamates 1 and 2 are pseudo‐substrate inhibitors of porcine pancreatic cholesterol esterase. Thus, the mechanism of the reaction necessitates that the inhibitor molecule and the enzyme form the enzyme‐inhibitor tetrahedral species at the Ki step of the reaction and then form the carbamyl enzyme at the kc step of the reaction. Linear relationships between the logarithms of Ki and kc for cholesterol esterase by carbamates 1 and σ are observed, and the reaction constants (ρs) are −3.4 and −0.13, respectively. Therefore, the above reaction forms the negative‐charge tetrahedral species and follows the formation of the relatively neutral carbamyl enzymes. For the inhibition of cholesterol esterase by carbamates 2 except 4‐nitrophenyl‐N‐phenyl carbamate and 4‐nitrophenyl‐N‐t‐butyl carbamate, linear relationships of ‐logKi and logkc with σ* are observed and the ρ* values are −0.50 and 1.03, respectively. Since the above reaction also forms the negative‐charge tetrahedral intermediate, it is possible that the Ki step of this reaction is further divided into two steps. The first Ki step is the development of the positive‐charge at the carbamate nitrogen from the protonation of the carbamate nitrogen. The second Ki step is the formation of the tetrahedral intermediate with the negative‐charge at the carbonyl oxygen. From Arrhenius plots of a series of inhibition reactions by carbamates 1 and 2, the isokinetic and isoequilibrium temperatures are different from the reaction temperature (25°C). Therefore, the observed ρ and ρ* values only depend upon the electronic effects of the substituents. Taken together, the cholesterol esterase inhibition mechanism by carbamates 1 and 2 is proposed.
The Chemical Constituents from the Heartwood of Eucalyptus Citriodora
Authors: Lee Ching‐Kuo , Chang Ming‐Huey
Published: May 2015

Nineteen compounds were isolated from the CHCl3 soluble portion of the heartwood of Eucalyptus citriodora. These compounds included trans‐calamenene (1), T‐muurolol (2), α‐cadinol (3), 2β‐hydroxy‐α‐cadinol (4), 4‐hydroxy‐3,5‐dimethoxybenzaldehyde (5), 4‐hydroxy‐3,5‐dimethoxybenzoic acid (6), linoleic acid (7), squalene (8), α‐tocopherol (9), erythrodiol (10), morolic acid (11), betulonic acid (12), cycloeucalenol (13), cycloeucalenol vernolitate (14), β‐sitosterol (15), β‐sitosteryl‐β‐D‐glucopyranoside (16), β‐sitostenone (17), yangambin (18), sesamin (19). Among them, 14 is a new compound. The structures of these compounds were elucidated on the basis of spectroscopic evidence.
Effects of Gamma Radiation on Various Polyimides
Authors: Liu Daniel Chun‐Hung , Liaw Der‐Jang , Liaw Been‐Yang , Tsai Chih‐Hung , Ho Jinn‐Hsuan , Ho Tong‐Ing
Published: May 2015

Four polyimides (PIa‐PId) containing 4,4′‐hexafluoroisopropylidene‐bisphthalic anhydride (6FDA) units in the backbone were prepared via one‐step synthesis. The effects of different doses of gamma radiation from a cobalt‐60 source are studied. The irradiated and the unirradiated polyimides are characterized by using tensile strength, infrared (IR), viscosity, differential scanning calorimeter (DSC), and gel permeation chromatography (GPC). All polyimides show the increase of tensile strength and elongation at low doses (>350 Mrad). The molecule weights decrease as the irradiation doses increase. All samples showed a drastic degradation of the mechanical and thermal properties at doses above 1400 Mrad. Samples irradiated at a dose of 2800 Mrad were completely brittle. The major difference of the radiation effect of the polyimides depends largely on their structural differences. PId with an extra hexafluoroisopropylidene moiety is most sensitive to irradiation at high doses.
Femtosecond Dynamics of Hydrogen Bonds in Liquid Water: A Real Time Study
Authors: Lascoux Noelle , Gallot Guilhem , Hache Francois , Gale Geoffrey Mitchell , Bratos Savo , Leicknam Jean‐Claude
Published: May 2015

An experiment is described to study temporal variations of the hydrogen bond length in diluted HDO/D2O solutions. The principles of this laser spectroscopic experiment are explained first. The construction of a laser source generating 150 fs pulses in the 2.5‐4.5 μm spectral region at a 10 μJ power level is detailed next. The OH stretching band is reproduced for different excitation frequencies and different pump‐probe delay times. A theory, based on statistical mechanics of nonlinear optical processes, is proposed to calculate the lowest two spectral moments. A new effect is reported, the delay dependent vibrational solvatochromism. It is shown how this effect can be exploited to follow temporal variations of the OH…O bond length directly, in real time. Initially elongated hydrogen bonds were found to contract with time and to reach the equilibrium lengths. The corresponding times scales are of the order of 700 fs. No bond oscillations are observed.
Photodissociation Dynamics of Chloroiodomethane in Acetonitrile Studied by Ultrafast Pump‐Probe Spectroscopy
Authors: Tarnovsky Alexander N. , Wall Magnus , Rasmusson Marcus , Pascher Torbjörn , Åkesson Eva
Published: May 2015

We have studied the photodissociation dynamics of chloroiodomethane (CH2ICl) in acetonitrile by ultrafast pump‐probe spectroscopy. The reaction was initiated using a femtosecond pulse at 266 nm and the transient absorption was measured out to delays of 300 ps over a spectral region from 330 to 850 nm. The photodissociation leads to formation and subsequent vibrational cooling of a product species, which we suggest is the isomer of chloroiodomethane, CH2Cl‐I, likely produced via in‐cage recombination between the nascent fragments CH2Cl and I.
Femtosecond Two‐Dimensional Infrared Spectroscopy
Authors: Hochstrasser Robin M. , Asplund Matthew C. , Hamm Peter , Ge Nien‐Hui
Published: May 2015

The dynamics occurring amongst the structures of peptides and small proteins present significant questions that are not readily addressed by conventional methods. Multiple pulse infrared experiments provide a promising alternative. The time resolution is easily fast enough to intercept the structures on different parts of the free energy surfaces. This paper reviews how infrared spectroscopy can be optimized by stretching it into two dimensions thereby making it possible to separately examine and assign the cross peaks arising from the interaction of different amide oscillators in the molecule. A variety of approaches such as pump/probe, self‐heterodyned pump/probe, three pulse photon echo and spectrally resolved echoes are described which are analogous to magnetic resonance schemes.
Metal Imido Complexes (M=Ti, W) Containing 2‐(Dimethylaminomethyl)pyrrole: Synthesis and the Crystal Structures of ButN=TiCIPy2[2‐Me2NCH2(C4H3N)] and PhN=WCl3[2‐Me2NCH2(C4H3N)]
Authors: Huang Jui‐Hsien , Chi Liang‐Sheng , Huang Feng‐Mau , Kuo Pei‐Cheng , Zhou Chong‐Chin , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

A titanium imido complex, ButN=TiClPy2[2‐Me2NCH2‐(C4H3N)] 1, was synthesized through metathesis by reacting ButN=TiCl2Py3 with lithium 2‐(dimethylaminomethyl) pyrrolate (LLi) in diethyl ether at room temperature. The dark brown red crystals were obtained from a concentrated diethyl ether solution of compound 1at −20°C and the monoclinic crystal shows a distorted octahedral structure with two pyridines taking trans positions. Hydrolysis ButN=TiCl2Py3 with 2,2′‐methylene‐bis(6‐t‐butyl‐4‐methylphenol) (HO∼∼CH2∼∼OH)generates a bis phenoxide titanium complex, (O∼∼CH2∼∼O)TiCl2Py 2, by eliminating one equivalent of ButNH2. Similarly, the reaction of LH with PhN=WCl4(OEt2) in diethyl ether at room temperature generates PhN=WCl3(L) 3, in moderate yield. 3has been characterized by NMR spectroscopies and X‐ray crystallography.
Synthesis of β‐D‐Glucopyranosyl(1→3)‐1‐thiol‐β‐glucosamine Disaccharide Derivative as Building Block for the Synthesis of Hyaluronic Acid
Authors: Lin Chun‐Cheng , Hsu Tzu‐Sui , Lu Kuo‐Cheng , Huang I‐Ting
Published: May 2015

A practical synthetic method for the title disaccharide 2 is described. Glycosylation using thioglycoside as acceptor and glycosyl imidate as donor was performed with trimethylsilyltriflate as the promoter.
An Interesting Isomerization: Synthesis of Mesoionic 5‐Arylamino‐1,3,4‐Thiadiazolium‐2‐Thiolates by Using ω‐Bromo‐ω‐(1H‐1,2,4‐Triazol‐1‐yl)acetophenone as Catalyst
Authors: Chang‐HuChu  , Hui Xin‐Ping , Xu Peng‐Fei , Zhang Zi‐Yi , Li Zhi‐Chun , Liao Ren‐An
Published: May 2015

Mesoionic 5‐arylamino‐1,3,4‐thiadiazolium‐2‐thiolates 7a‐f were prepared by the isomerization of 5‐arylamino‐1,3,4‐thiadiazol‐2‐thiones 5a‐f by using ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone 6 as catalyst. All the structures of mesoionic synthesized were confirmed by elemental analyses, 1H NMR, IR and MS spectral data. We have also determined the x‐ray photoelectron spectroscopy (XPS) of the mesoionic and their precursors. A comparison of XPS spectra between the mesoionic and their precursors showed that the charge separation in mesoionic is distinctly larger than in their precursors.
Studies on Polyfunctionalised Heteroaromatics: Synthesis of Several New Cinnoline and Pyrido[3,4‐c]pyridazine Derivatives
Authors: Barsy Magda A.
Published: May 2015

One‐pot reaction of ethyl 2‐aryhydrazono‐3‐oxobutyrates with cyanoacetamide afforded pyridazine and pyridine derivatives, which were found to be excellent precursors for the synthesis of different cinnolines and pyrido[3,4‐c]pyridazines, respectively.
Heterocyclic Fused Rings with Bridgehead Nitrogen Atoms: Single‐Step Synthesis of Azolo[1″,2″:1′,2′]pyrido[5′,6′:5,4]pyrimido[1,6‐a]benzimidazole; Pyrido[1,2‐a]benzimidazole; Pyrido[4″,5″:2′,3′]pyrido[6′,5′:4,5]pyrimido‐[1,6‐a]benzimidazole and Polysubstituted Pyridine Derivatives
Authors: Raslan M. A.
Published: May 2015

A one‐step synthesis of the title compounds by the reaction of arylidene‐lH‐benzimidazol‐2‐ylacetonitriles 1a‐d with 2‐cyanomethylbenzimidazole derivatives 2a,b is reported.
Dissociation Kinetics of Cerium(lll) Complexes of Macrocyclic Polyaza Polycarboxylate Ligands TETA and DOTA
Authors: Chang C. Allen , Liu Yuh‐Liang
Published: May 2015

The acid‐catalyzed dissociation rate constants of the cerium(III) complexes of 1,4,8,11‐tetraazacyclo‐tetradecane‐1,4,8,11‐tetraacetic acid (TETA) and 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) have been determined at four different temperatures (i.e., 25.0°C,32.0°C,39.0°C,45.0°C) in aqueous media (μ = 0.10 M, HCl/KCl) to obtain additional kinetic data and to evaluate possible effects of ligand pre‐organization for metal ion complexation. The rates are much faster for Ce(TETA)− than for Ce(DOTA)−, indicating the lower thermodynamic stability of the former. In the presence of excess strong acid, 0.1‐1.0 MHCl, the dissociation reactions follow the rate law: ‐d[ML]T/dt = (kd + kH[H+])[ML]T and ‐d[ML]T/dt = (kH[H+] + kH2[H+]2)[ML]T, respectively, where kd is acid‐independent dissociation reaction rate constant and kH and kH2 are the respective dissociation rate constants for the pathways involving monoprotonated and diprotonated species. The rate activation parameters, ΔH≠, ΔS≠ and ΔG≠, for each dissociation pathway have been obtained and their values are consistent with the proposed mechanisms. In particular, the rate difference between Ce(TETA)−and Ce(DOTA)− for the monoprotonated complex dissociation pathway is mainly due to difference in ΔHH≠. It has been concluded that ligand pre‐organization results in more stable complexes and slower complex dissociation rates.
Protein Folding and β‐Sheet Proteins
Authors: Kumar Thallampuranam Krishnaswamy Suresh , Sivaraman Thirunavukkarasu , Samuel Dharmaraj , Srisailam Sampath , Ganesh Gopal , Hsieh Hui‐Chu , Hung Kuo‐Wei , Peng Ho‐Jen , Ho Meng‐Chiao , Arunkumar Alphonse Ignatius , Yu Chin
Published: May 2015

The aim of this comprehensive review is to critically evaluate the progress in research in the area of protein folding. In the first section, we discuss the various models proposed to explain the protein folding paradox. In the succeeding section of the review, a detailed account of the developments in our understanding of the folding path ways of β‐sheet proteins is provided.
Time‐Resolved Phase Transitions of the Nanocrystalline Cubic to Submicron Monoclinic Phase in Mn2O3‐ZrO2
Authors: Lajavardi Manouchehr , Kenney Donald J. , Lin Sheng Hsien
Published: May 2015

The nanocrystalline cubic phase of zirconia was found to be thermally stabilized by the addition of 3 to 40 mol % manganese. The nanocrystalline cubic, tetragonal and monoclinic phases of zirconia stabilized with manganese (III)oxide (Mn‐Stabilized Zirconia) were prepared by thermal decomposition of carbonate and hydroxide precursors. Both the crystallization and isothermal phase transitions associated with Mn‐SZ were studied using high temperature x‐ray diffraction and x‐ray diffraction of quenched samples. Cubic Mn‐SZ initially crystallized and progressively transformed to tetragonal, and monoclinic structures above 700°C. The nanocrystalline cubic Mn‐SZ containing 25 mol % Mn was found to have the greatest thermal stability, retaining its cubic form at temperatures as high as 800°C for periods up to 25 hours. Higher than 40 mol %, cubic Mn2O3 was found to coexist with cubic Mn‐SZ. The crystallite sizes observed for the cubic, tetragonal and monoclinic Mn‐SZ phases ranged from 50 to 137, 130 to 220, and 195 to 450 Å respectively, indicating, for ZrO2, that particle size was a primary factor in determining its polymorphs. The classical Avrami equation for nucleation and growth was applied to the observed phase transformations.
Time‐Resolved High and Low Temperature Phase Transitions of the Nanocrystalline Cubic Phase in the Y2O3‐ZrO2 and Fe2O3‐ZrO2 System
Authors: Lajavardi Manouchehr , Kenney Donald J. , Lin Sheng Hsien
Published: May 2015

The nanocrystalline cubic Phase of zirconia was found to be thermally stabilized by the addition of 2.56 to 17.65 mol % Y2O3 (5.0 to 30.0 mol % Y, 95.0 to 70.0 mol % Zr cation content). The cubic phase of yttria stabilized zirconia was prepared by thermal decomposition of the hydroxides at 400°C for 1 hr. 2.56 mol % Y2O3‐ZrO2 was stable up to 800°C in an argon atmosphere. The samples with 4.17 to 17.65 mol % Y2O3 were stable to 1200°C and higher. All samples at temperatures between 1450°C to 1700°C were cubic except the sample with 2.56 mol % Y2O3 which was tetragonal. The crystallite sizes observed for the cubic phase ranged from 50 to 150 Å at temperatures below 900°C and varied from 600 to 800 nm between 1450°C and 1700°C. Control of furnace atmosphere is the main factor for obtaining the cubic phase of Y‐SZ at higher temperature.

Nanocrystalline cubic Fe‐SZ (Iron Stabilized Zirconia) with crystallite sizes from 70 to 137 Å was also prepared at 400°C. It transformed isothermally at temperatures above 800°C to the tetragonal Fe‐SZ and ultimately to the monoclinic phase at 900°C. The addition of up to 30 mol % Fe(III) thermally stabilized the cubic phase above 800°C in argon. Higher mol % resulted in a separation of Fe2O3. The nanocrystalline cubic Fe‐SZ containing a minimum 20 mol % Fe (III) was found to have the greatest thermal stability. The particle size was a primary factor in determining cubic or tetragonal formation. The oxidation state of Fe in zirconia remained Fe3+. Fe‐SZ lattice parameters and rate of particle growth were observed to decrease with higher iron content. The thermal stability of Fe‐SZ is comparable with that of Ca‐SZ, Mg‐SZ and Mn‐SZ prepared by this method.
Preparation of Thaliporphine and Lirioferine from Glaucine by Treatment with Hydrogen Bromide
Authors: Rao N. S. Kameswara , Lee Shoei‐Sheng
Published: May 2015

Glaucine (2), an aporphine alkaloid, when treated with HBr gas in dichloromethane for five days at room temperature afforded thaliporphine (1), a potent cardiotonic agent, lirioferine (7), N‐methyllaurotetanine (8) and bracteoline (9), in 20%, 10%, 4% and 7% yields, respectively. The same products were obtained in the yields of 26% (1), 15% (7), 10% (8) and 12% (9) when glaucine was refluxed with acetic acid saturated with HBr gas for one hour. This study provides an alternative method to prepare thaliporphine and is the first semisynthesis for lirioferine.
Synthesis of N‐(1‐oxyl‐2,2,5,5‐tetramethylpyrrolin‐3‐yl)‐N′‐(3‐aryl‐5‐mercapto‐1,2,4‐triazol‐4‐yl)ureas and N‐(3‐aryl‐5‐mercapto‐1,2,4‐triazol‐4‐yl)‐(1‐oxyl‐2,2,5,5‐tetramethylpyrrolin‐3‐yl)acidamide
Authors: Zhang Yan , Sun Xiao‐Wen , Zhang Zi‐Yi , Wang Qin , Wang Shu‐Fang
Published: May 2015

Nine novel N‐(1‐oxyl‐2,2,5,5‐tetramethylpyrrolin‐3‐yl)‐N′‐(3‐aryl‐5‐mercapto‐1,2,4‐triazol‐4‐yl)ureas 3a∼3i were synthesized by the reaction of 1‐oxyl‐2,2,5,5‐tetramethylpyrrolin‐3‐yl isocyanate 1 with 4‐amino‐3‐aryl‐5‐mercapto‐1,2,4‐triazoles 2a∼2i and their anti‐tumor activity was evaluated. The mass spectra of the compounds synthesized were discussed.
Synthetic Studies of a Didemnin B Analog Based on a 2,3‐Diamino Sugar Scaffolding
Authors: Ramanjulu Joshi M. , Joullié Madeleine M. , Li Wen‐Ren
Published: May 2015

Reductive amination, amide formation using BOP [(1H‐1,2,3‐benzotriazol‐1‐yloxy)tris(dimethylamino)‐phosphonium hexafluorophosphate] and esterification via DCC (dicyclohexylcarbodiimide) were the key synthetic steps to generate an advanced intermediate in the preparation of a didemnin B analog based on a sugar scaffolding (2). This analog should provide insight into the bioactive conformation of didemnin B.
Synthesis and Biological Activity of Some New Diaryl Sulphones Containing Fused Thiazolo Pyrimidines
Authors: Kandeel Maymona M.
Published: May 2015

This paper describes the synthesis of some pyrimido[2,1‐b]benzothiazol‐8‐yl sulphones (7, 9, 11, 13, 14, 16) starting from bis[2‐aminobenzothiazol‐6‐yl)sulphone 1. Reaction of 1 with acetic anhydride and/or benzoyl chloride gave substituted amino derivatives 2a,b, whereas its reaction with phenacyl bromide and/or p‐chlorophenacyl bromide gave imidazo benzothiazol‐7‐yl sulphones 4a,b.
Generation of 9(10H)‐Acridone from Anthranilic Acid
Authors: Ho Tse‐Lok , Jou Der‐Guey
Published: May 2015

Diazotization of anthranilic acid with butyl nitrite in refluxing THF gave rise to acridone.
A Novel MHDV Descriptor for Dipeptide QSAR Studies
Authors: Liu Shushen , Yin Chunsheng , Cai Shaoxi , Li Zhiliang
Published: May 2015

A novel molecular holographic distance vector (MHDV) is proposed to characterize the structures of the peptide molecules and employed to relate to the biological activities of the peptides by means of principal component regression (PCR) method. For two pan els of dipeptides, the correlation coefficient (R) between the estimated and the observed activities are respectively 0.9370 and 0.9585 and the R obtained by cross‐validation method are respectively 0.8676 and 0.9295, which is the best result to date for the two sets of dipeptides. The novel MHDV descriptor only depends on distance matrix and various atomic types of non‐hydrogen atoms in a molecule and requires no 3D structural information, so, it is a very simple and easy to use descriptor.
Asymmetry and Spin Polarization Parameters of Photoelectrons from the Zn Atom
Authors: Wang Lin‐Ru , Huang Keh‐Ning
Published: May 2015

Asymmetric and spin polarization parameters of photoelectrons from the neutral zin atom are obtained by using the relativistic random‐phase approximation (RRPA). These parameters in the energy range near the first ionization thresh old are very sensitive to valence‐core correlations. The present results are in good agreement with recent measurements.
Cylindrical and Spherical Microcavity Lasers Based on Evanes Cent‐Wave‐Coupled Gain
Authors: An Kyungwon
Published: May 2015

We report operation of microcavity lasers based on the gain only in the evanes cent field region of whispering gallery modes. Two types of microcavities, microsphere and microcylinder, were used. First a cylindrical microcavity of 125 micron in diameter was surrounded by Rhodamine 6G dye molecules in ethanol solution of lower refractive index such that WGM's of the microcavity undergo laser oscillation when the dye molecules in the evanescent field region out side the cavity are excited by a second harmonic of a Nd: YAG laser. In the second experiment an ultrahigh Q microsphere was used for a cavity. The dye molecules out side the sphere, near the equator, of 102 μm diameter were excited, resulting in WGM lasing in the lowest radial mode order. The loaded quality factors of the cavity in this case were found to exceed 2 × 109, which would be high enough to support lasing with only a single quantum radiator coupled to the WGM.
Fine‐structure in 3d4 States of Highly Charged Ti‐like Ions
Authors: Kato Daiji , Tong Xiao‐Min , Watanabe Hirofumi , Fukami Tsunemitsu , Kinugawa Tohru , Yamada Chikashi , Ohtani Shunsuke , Watanabe Tsutomu
Published: May 2015

A remarkable improvement of ab initio calculations was obtained for wavelengths of (3d4) J = 3 → 2 forbid den transition. Present calculations reduced the long‐standing discrepancy from measurements down to less than 0.2% for most high‐Z titanium‐like ions. In the present calculations, a large extent of configuration space was included so that most important many‐body effects were taken into account. To this end, the linearized second‐order Brillouin‐Wigner perturbation theory was employed with optimized spin‐orbitals. Transition probability and atomic g‐factor were also calculated with the improved atomic wave functions.
Magnetic Guide and Trap for Cold Neutral Atoms with Current‐Carrying Wires and Conductors
Authors: Yin Jianping , Gao Weijian , Liu Nanchun , Hu Jianjun , Wang Yuzhu
Published: May 2015

We propose two novel schemes for guiding cold, neutral atoms using static magnetic fields generated by several cylindrical arrays of current‐carrying wires or a few different‐shaped (V‐, or U‐shaped, etc.) current‐carrying conductors, and calculate the corresponding magnetic‐field contours and their trapping potentials. Our study shows that some guiding schemes can be used to form an atomic funnel, or an atomic beam‐splitter, or even construct an atomic interferometer, and some guiding schemes can be used to realize a single‐mode wave guide of ultracold atoms (or coherent matter waves, BEC) under certain conditions. We also propose a few new schemes to microscopically trap neutral atoms by using various planar arrays of current‐carrying wires and calculate the spatial distribution of the magnetic fields. Our research shows that these microtrap arrays can be used to form 1D, 2D or 3D atomic magnetic lattices, and then to prepare 1D, 2D or 3D photonic crystals, even to realize a 1D, 2D or 3D array of magnetically‐trapped BECs or Bose Clusters.
Quantum Effects in Potential‐Well Scattering
Authors: Cheng Wen‐Yu , Huang Keh‐Ning
Published: May 2015

Particle scattering through a spherical potential well is treated by three successive procedures to demonstrate the quantum effects. The differential cross section from a geometric treatment as in geometric optics consists of an incoherent sum of components associated with each geometric path, while the geometric‐phase treatment gives rise to the coherence among components. By considering Huygens' principle, the wave treatment as in wave optics brings an additional term to the differential cross section, which corresponds to the Fraunhofer diffraction in optics.
Kinetics and Mechanism of Dehydrochlorination of 3‐Chloro‐1,5‐diarylformazans and Their Mass Spectra
Authors: Shawali Ahmad S. , Abdelkhalek Ahmad A. , Sayed Abdelwahed R.
Published: May 2015

In aqueous dioxane containing triethylamine the title 3‐chloroformazans 1 are converted into the corresponding 1,4‐bis(arylazo)‐3,6‐diaryl‐1,2,4,5‐tetrazines 3 via head‐to‐tail dimerization of the intitially formed 1,3‐dipolar ions 2. The kinetics of triethylamine‐catalyzed dehydrochlorination of 1 in 70% dioxane at 27°C and ionic strength of 0.1 were studied. The rate data were linearly correlated with enhanced Hammett substituent constants σx− and an overall ρ value of 0.2 was determined for the variation of the N‐aryl substituent. These results were interpreted in terms of a two‐step mechanism. Also, the mechanisms of the unimolecular fragmentation of 1 and 3 in the mass spectrometer are discussed.
Structure and Magnetic Property of a Novel Nitronyl Nitroxide Biradical
Authors: Zhao Qi‐Hua , Jiang Zong‐Hui , Liao Dai‐Zheng , Yan Shi‐Ping , Fang Rui‐Bin
Published: May 2015

A new biradical of nitronyl nitroxide, 1,3‐[di‐2‐(4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) phenoxy]propane [BNITPhOPr (1)], was prepared and characterized. The temperature dependence of the magnetic susceptibility values were observed for 1 in the range of 2–300 K. The observed data was successfully simulated giving the exchange integral J = −0.47 cm−1, θ = −0.94 K. This result indicates a weak antiferromagnetic spin exchange interaction between the biradicals.
Synthesis and Biological Activity of New Selected Different Heterocyclic Nitrogen Compounds Incorporating 1,4‐naphthquinone
Authors: Khalafallah Ali Kamel
Published: May 2015

Condensation of 1‐phenylnaphthcyclopentan‐2,4,9‐trione (II) with aromatic aldehydes yielded the corresponding 3‐benzylidene deivatives (IIIa‐f). Interaction of IIIa‐f with hydrazines, hydroxylamine, urea and thiourea afforded some new (pyrazoline IVa‐f, Va‐f, Isoxazolino VIa‐f pyrimidinone and/or pyrimidinethione, VIIa‐f, VIIIa‐f) derivatives, respectively. Also, a series of some spirocompounds covering β‐lactams and thiazolidinones (Xg‐j, XIg‐j) incorporating 1‐phenylnaphthcyclopentan‐2,4,9‐trione were prepared.
Ceramides from the Taiwan Red Alga Ceratodictyon Spongiosum and Symbiotic Sponge Sigmadocia Symbiotica
Authors: Lo Jir‐Mehng , Wang Wei‐Lung , Chiang Young‐Meng , Chen Chiu‐Ming
Published: May 2015

The structure of a mixture of ceramides (1) de rived from 2‐amino‐4(E)‐alkene‐1,3‐diol sphingenines with C22, C23, and C24 saturated fatty acid residues from red alga Ceratodictyon spongiosum ZANARDINI (Rhodymeniaceae) containing the symbiotic sponge Sigmadocia symbiotica has been elucidated on the basis of spectroscopic and chemical evidence. In addition, one new sterol, n‐nonadecanoic acid 24‐ methylenecholesteryl ester (2), and six known sterols were also isolated from the marine organisms.
Reaction of (η5‐C5H5)Fe(CO)2I with Anionic Bidentate Phosphine Ligands PPh2(o‐C6H4NHLi) or PPh2(o‐C6H4OLi)
Authors: Peng James , Wen Yuh‐Sheng , Liu Ling‐Kang
Published: May 2015

The o‐substituted hybrid phenylphosphines, PPh2(o‐C6H4NH2) and PPh2(o‐C6H4OH), could be deprotonated with LDA or n‐BuLi to yield PPh2(o‐C6H4NHLi) and PPh2(o‐C6H4OLi), respectively. When added to a solution of (η5‐C5H5)Fe(CO)2I at room temperature, these two lithiated reagents produce a chelated neutral complex 1 (η5‐C5H5)Fe(CO)[C(O)NH(o‐C6H4)PPh2‐C,P‐η2] for the former and mainly a zwitterionic complex 2, (η5‐C5H5)Fe+(CO)2[PPh2(o‐C6H4O−)] for the latter. Complex 1 could easily be protonated and then decarbonylated to give 4 [(η5‐C5H5)Fe(CO){NH2(o‐C6H4)PPh2‐N,P‐η2}+]. Complexes 1 and 4‐I have been crystallographically characterized with X‐ray diffraction.
Reduction of Ethyl t‐Cinnamates by Samarium Diiodide
Authors: Lin Tzuen‐Yeuan , Fuh Ming‐Ren , Chan I‐San
Published: May 2015

Rate constants directly measured from the GC‐analyzed method for SmI2 reduction of ethyl t‐cinnamate and its substituted derivatives in the presence of HMPA and t‐butanol were obtained. HMPA exhibits a stronger catalytic effect than t‐butanol. Dependence of reaction rates on concentration of SmI2 and temperature were studied. Electron‐donating groups retard this reduction; the electron‐withdrawing groups, on the other hand, enhance the reaction rates dramatically.
Simple Protocol for Synthesis and Cleavage of Tetrahydropyranyl Ethers Using FeSO4 as an Inexpensive Catalyst
Authors: Bandgar Babasaheb P. , Kasture Suhas P.
Published: May 2015

Protection and deprotection of alcohols and phenols as tetrahydropyranyl ethers (THP ethers) using an hydrous FeSO4 under microwave irradiation without solvent is carried out.
Facile Synthesis and Biological Evaluation of Some Heterocyclic Systems Containing Diazepam
Authors: Berghot M. A.
Published: May 2015

Oxadiazoles 4, 5, 6, 12, 14 and 22 were prepared binary attached with Diazepam (1). Thiadiazoles 15, 20 and Triazoles 7, 8, 9, 17, 18, 19 and 21 were also prepared. The structures of hitherto unknown compounds were confirmed by analytical and spectral methods. Some of the synthesized compounds were screened to test their antibacterial activity.
Preparation of Hydroquinone‐Containing Polymers by ROMP
Authors: Chow Tahsin J. , Yang Ya‐Chen , Chiu Nan‐Yun , Hsu Ming‐Ann
Published: May 2015

Polymers containingortho‐ andpara‐hydroquinone moieties5a,band6aare prepared in good yields by ROMP from hydroquinone‐fused norbornadiene derivatives1a,band2a. Oxidation of5byielded a quinone derivative7, which is evidenced by a strong absorption at 1656 cm−1in infrared spectrum.
Dynamics and Orientation Ordering of Water in Lyotropic Liquid Crystals Using 2H Double Quantum Filtered NMR Spectral Analysis
Authors: Cheng Chi‐Yuan , Hwang Lian‐Pin
Published: May 2015

The alignment of lyotropic liquid crystals in a magnetic field has been studied by line shape analysis of the T1 process and 2D 2H double quantum filtered (DQF) NMR to investigate water dynamics and orientational feature in Cetyltrimethylammonium bromide (CTAB)/Sodium Salicylate (NaSal)/D2O liquid crystals. The same system but in powder form was also examined. In the ordered liquid‐crystalline phase, the single quantum line shapes showed splitting of doublets due to the residual quadrupolar interaction, while the double quantum spectra observed splitting patterns with damped oscillation. The modified cone model is invoked to describe the restricted motions of bound D2O molecules. Ten to thirteen bound water molecules are found to associate with each CTAB molecule and the correlation time of wobbling motion of the bound water is in the time scale of 10−8 s. At 10°C, the motional correlation times of water in the powder sample have the same magnitude as those in the oriented sample. This study shows that the analysis of DQF relaxation spectra provides a more detailed source of motional information than the normally used measurements.
Room Temperature Phosphorescence of Aromatic Hydrocarbons in SDS Rodlike Micelles
Authors: Huang Jen‐How , Lin Wann‐Yin
Published: May 2015

Room temperature phosphorescence (RTP) of aromatic hydrocarbons has been investigated in deoxgenated SDS micelles and in the presence of a hydrophobic heavy‐atom containing species. No RTP was observed in spherical or sub‐rodlike micelles. In the presence of a heavy‐atom containing species, a tremendous increase in phosphorescence intensity was observed during the sphere‐to‐rod transition induced by the addition of a strong electrolyte. The increased microviscosity and the incorporation of more heavy atoms during the micellar elongation will lead to an increase in the rate of intersystem crossing and a decrease in the rates of nonradiative processes, favoring the observation of RTP. At high temperatures, the phosphorescence intensity is reduced dramatically probably because of the decrease in rigidity and aggregation number of the micelle with less heavy atoms incorporated. Various heavy‐atom containing species induce RTP to a different extent. Iodoethane exhibits the most prominent heavy atom effect. 1,2‐Dibromoethane, 1‐bromopropane, and bromobenzene are about 40% as efficient as iodoethane in inducing RTP, while long‐chain 1‐bromoalkanes and polar species are much less efficient. This study demonstrates the feasibility of detecting RTP in deoxygenated SDS rodlike micelles using a suitable hydrophobic heavy‐atom containing species.
Synthesis of Symmetric and Unsymmetric 1,1′‐Dialkenylferrocenes via Samarium Diiodide Promoted Reactions of 1,1′‐Diacetylferrocene with Halides
Authors: Jong Shean‐Jeng , Fang Jim‐Mm , Liu Yi‐Hung , Wang Y.
Published: May 2015

Monoalkenylferrocenes were prepared from 1,1′‐diacetylferrocene and appropriate benzyl bromides by the promotion of samarium diiodide. A practical method for preparation of both symmetric and unsymmetric dialkenylferrocenes was also explored. The reactions were stereoselective to give only (E) double bonds. The unsymmetric dialkenylferrocene bearing electron‐donating substituent (e.g. methoxy group) and electron‐withdrawing substituent (e.g. cyano group) on different phenyl rings likely exhibits a large nonlinear optical property.
Spectrophotometric and Polarographic Studies on the Kinetics of Hydrolysis of N‐(6‐Methyl‐5‐Nitropyridin‐2‐yl Methylidene)‐N′‐(Substituted Thiazol‐2‐yl)Hydrazines
Authors: El‐Nady Abobakr M.
Published: May 2015

The kinetics of the hydrolysis of hydrazone de rived from nitropyridine 2‐carboxaldehyde and 2‐hydrazino‐4‐substituted thiazoles Ia‐e in 10% (v/v) DMF‐buffer mixture has been investigated by applying two in dependent and different techniques viz UV‐spectrophotometry and differential pulse, polarography (DPP). The hydrolysis has been found to follow general acid‐base catalysis. Mechanism for the hydrolysis in acidic medium has been postulated. The observed rate constants, activation and thermodynamic parameters for the hydrolysis have been calculated. The effects of pH, molecular structure, temperature and change in percent age of water in the DMF‐buffer mixture on the rate of hydrolysis have been discussed.
Thermodynamic Study of the Ion‐Pairing of Some Transition Metal Perchlorates in Urea‐Water Mixtures from Conductivity Measurements
Authors: Bakr Moustafa Farag
Published: May 2015

The conductivity of some transition metal perchlorates, M(ClO4)2 (M2+ = Mn, Co, Ni, Cu and Zn) has been measured in urea‐water mixtures at 288–318 K. The limiting molar conductivities and the ion association constants of these electrolytes were calculated by the Shedlovsky extrapolation method. The ion association constants de creased in the order Co > Ni > Zn with increasing the atomic number, whereas Cu > Mn in the ionic association constants as are suit of the maximum temperature dependencies of Cu2+.

The thermodynamic functions, ΔH° and A S°, for the formation of that ion pair have also been obtained.

Both ΔH° and ΔS° for all the salts under study are positive values. On the other hand, the Walden products, Δoη, of the salts in crease with an in crease in temperature at 288–318 K, which indicate that these electrolytes be have as structure‐makers or promotors. Also, the activation energies, E, have been calculated and discussed.
Extraction of Palladium(II) with Cyanex‐923 and Cyanex‐471X from Bromide Media and its Separation from Pt(IV), Rh(III) and Ir(III)
Authors: Duche Sharad N. , Dhadke Purashottam M.
Published: May 2015

The distribution equilibria of Pd(II) between aqueous bromide media and Cyanex‐923 as well as Cyanex‐ 471X in toluene was studied as a function of the concentration of extractants and the acid concentration. The extraction behaviour of Cyanex‐471X is compared with Cyanex‐923 as they contain different donor atoms. The quantitative extraction of Pd(II) was observed with Cyanex‐923 in toluene from 4.0–8.0 mol l−1 HBr media and was stripped out with 2.0 mol l−1 hydrochloric acid. Similarly Pd(II) was quantitatively extracted with Cyanex‐471X in toluene from 6.0–8.0 mol l−1 HBr media and was stripped out with 7.0 mol l−1 NH3 solution as well as 1.0 mol l−1 of stabilized sodium thiosulfate solution at pH 4.4. The stoichiometry of the Cyanex‐923 and Cyanex‐471X extracted species determined from slope analysis was 1:2 and 1:1, respectively. Palladium(II) was extracted and separated from its binary and ternary mixture.

These methods were successfully employed for analysis of palladium in real samples.
Synthesis of 2,6‐Dioxatetracyclo[6.3.0.01,10.07,8]undecane and 2,7,12‐Trioxatetracyclo[6.3.1.04,11.05,9]dodecane
Authors: Chang Meng‐Yang , Chen Shui‐Tein , Chang Nein‐Chen
Published: May 2015

The oxa‐cage compounds 1 and 2 are synthesized from the alcohol 3 by a series of functional trans formations. Syntheses of novel skeletons 6 and 8 are also de scribed.
Synthesis and Mesomorphic Properties of Mesogens Containing Tetrafluorobiphenyl Carboxylate Groups
Authors: Chen Xi‐Mm , Wang Kan , Li Heng‐Feng , Liu Ke‐Gang , Wen Jian‐Xun
Published: May 2015

Six series of 4–4′‐n‐alkoxy‐2′,3′,5′,6′‐tetrafluorobiphenyl carboxylate esters have been synthesized. Their mesomorphic properties were investigated and measured by optical polarizing microscopy and DSC. The results show that tar get compounds bearing a nitro group as terminal group exhibit wide mesophases. However, their terminal groups are trifluoromethyl, fluorine atoms, chlorine atoms, bromine atoms and hydrogen atoms, which aren't mesogens.
Synthesis of New Pyrazolo[3,4‐b]quinolines, Thieno[2,3‐b]quinolines and Related Condensed Heterocyclic Systems
Authors: Bakhite Etify Abdel‐Ghafar
Published: May 2015

3‐Amino‐1H‐pyrazolo[3,4‐b]quinoline (2) was reacted with benzaldehyde, acetylacetone, ethylacetoacetate and/or phenyl isothiocyanate to give compounds 3,4,5 and 6, respectively. The interaction of 6 with some α‐haloesters and/or α‐haloketones produced the corresponding thiazolidinones 7a‐c and thiazolines 9a‐d. 1H‐Pyrazolo[3,4‐b]quinoline‐3‐diazonium chloride (11) was coupled with some active methylene compounds to give the corresponding hydrazono compounds 12a,b and 13 which, in turn were cyclized into the corresponding triazinopyrazoloquinolines 14a,b and 15 by heating in acetic acid. 3‐Aminothieno[2,3‐b] quinoline‐2‐carbohydrazide (19) and 3‐amino‐2‐(1H‐benzimidazol‐2‐yl)thieno[2,3‐b]quinoline (21) were prepared and employed as key intermediates for synthesizing the second class of the title compounds.
Usefulness of Some Plant Flowers as Natural Acid‐Base Indicators
Authors: Soltan M. E. , Sirry S. M.
Published: May 2015

Environmental protection must require the use of natural products instead of chemicals to minimize pollution. Thus, this investigation studies the use of some plant flowers as naturally occurring acid‐base indicators. We utilized plant flowers of Celosiacristate Linn, Bombax ceiba L., Poincianaregia and Hibiscus subdariffa. These flowers contain anthocyanine pigments whose colour depends on pH; there fore they are used as pH indicators. The acid‐base equilibria of these pigments were investigated using spectro photometric and potentiometric methods. The pk values are 9.6 for Celosiacristate Linn, 5.7 for Bombax ceiba L., 8.6 for Poincianaregia and 2.8 & 7.3 for Hibiscus subdariffa. Experimentation of these indicators on different concentrations of acid‐base titrations in the presence of variable concentrations exhibited similar results as for synthetic indicators.
Synthesis and Antimicrobial Activity of Novel Furothienoquinoxalines, Pyranothienoquinoxalines and Pyrimidopyranothienoquinoxalines
Authors: Moustafa Osama S. , El‐Ossaily Yasser A.
Published: May 2015

The reaction of ethyl‐3‐mercaptoquinoxaline‐2‐carboxylate with phenacyl bromide, ethyl chloroacetate, chloroacetonitrile or chloroacetone furnished the corresponding 3‐hydroxy thieno[2,3‐b]quinoxaline. 2‐Cyano‐3‐hydroxythieno[2,3‐b]quinoxaline and 2‐acetyl‐3‐hydroxythieno[2,3‐b]quinoxa line were employed as precursors in the synthesis of some novel furo[2′,3′:4,5]thieno[2,3‐b]quinoxaline, pyrano[2′,3′:4,5]thieno[2,3‐b]quinoxaline and other heterocyclic systems fused with thieno[2,3‐b]quinoxalines. The antibacterial and antifungal activities of some the synthesised compounds were studied.
Synthesis and Antimicrobial Activity of New Pyridothienopyrimidines and Pyridothienotriazines
Authors: Abdel‐Rahman Abdu E. , Bakhite Etify A. , Al‐Taifi Elham A.
Published: May 2015

5‐Acetyl‐3‐amino‐4‐aryl‐6‐methylthieno[2,3‐b]pyridine‐2‐carboxamides (5a,b) were reacted with triethyl orthoformate or nitrous acid to give the corresponding pyrimidinones6a,b and triazinones 7a,b. The reaction of 5a,b with acetic anhydride was carried out and its products were identified as a mixture of 8‐acetyl‐9‐aryl‐2,7‐dimethylpyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐4(3H)‐one (9a,b) and related 5‐acetyl‐4‐aryl‐3‐biacetylamino‐6‐methylthieno[2,3‐b]pyridine‐2‐carbonitrile (10a,b). Reaction of 7a with some halocompounds afforded the N‐alkylated triazinones8a‐c. Chlorination of6a,b and 9a,b with phosphorus oxychloride produced 4‐chloropyrimidines 11a‐d which were used as precursors for the rest of the target heterocycles. Some of the prepared compounds were tested in vitro for their antimicrobial activities.
Studies on the Constituents from the Bark of Bauhinia Purpurea
Authors: Kuo Yueh‐Hsiung , Chu Pei‐Hung
Published: May 2015

In a previous paper, were ported a new stigmasteroyl glucoside derivative together with four known compounds. In addition to the above compounds, the isolation and identification of twenty‐four compounds from the same source are described here. Their structures were deter mined on the basis of spectral evidence as well as comparison with authentic samples. Those compounds included four waxes, four triterpenes, eight steroids, two glyceride, three flavonoids, and three phenylpropanoids. Some new compounds were found in mixtures of three alkyl ω‐hydroxyalkanoate, glyceride, and phenylpropanoids.
Temperature Dependent Dielectric Relaxation in Solvent Mixtures at Microwave Frequencies
Authors: Chaudhari Ajay , Chaudhari Harish , Mehrotra Suresh
Published: May 2015

By the use of time domain reflectometry method, dielectric measurements were carried out on dimethylformamide‐2‐nitrotoluene solvent mixtures in the frequency range 10 MHz‐20 GHz, at various temperatures from 15 °C to 45 °C. These solvent mixtures as well as pure solvents display a Debye type dispersion. Their frequency dependent dielectric properties can be summarized by the three parameters in the Debye equation: a static permittivity, permittivity at high frequency and a dielectric relaxation time constant. The free energy of activation for dipolar relaxation process and the Kirkwood correlation factor were determined using these fitting parameters for these solvent mixtures at various concentrations and temperatures. By using these dielectric parameters, the excess permittivity and excess inverse relaxation time is obtained. The excess permittivity is found to be positive for all concentrations and temperatures whereas the excess inverse relaxation time is negative.
Low‐Valent Ruthenium Induced Simultaneous Reduction of Nitro Group and C‐C Double Bond in Nitroolefin 1‐Phenyl‐2‐Nitropropene‐1
Authors: Li Yanjun , Izumi Taeko
Published: May 2015

The reduction of 1‐phenyl‐2‐nitropropene‐1 (1) on using ruthenium complexes was studied in detail in order to correlate this method with those previously recorded in the literature for the hydrogenation of nitroolefins. A variety of products was isolated by varying the reaction temperature and solvent. Among them was 1‐phenyl‐2‐propylamine (4), completely reduced from the selective both double bond and nitro group. 1‐Phenyl‐2‐propanol (5) was observed due to reduction of phenylacetone at 125 °C in the presence of ruthenium catalyst. When reaction temperature was lower than 125 °C, by employing RuCl2(PPh3)3 complex, 1‐phenyl‐2‐nitropropane (2) and phenylacetone (3) were obtained, respectively. Ru‐BINAP complexes were attempted to produce chiral amine from starting material 1‐phenyl‐2‐nitropropene‐1 (1).
Citric Acid Determination by Dual Wavelength Spectrophotometry
Authors: Farajzadeh Mir Ali , Nagizadeh Sepideh
Published: May 2015

In this study, a dual wavelength spectrophotometric method was presented on the basis of Cu2+‐NH3complex decomposition by the citrate ion and the formation of Cu2+‐citrate complex. Sum of the absorbance decreasing at 600 nm (λmaxfor Cu2+‐NH3complex) and the absorbance increasing at 750 nm (λmaxfor Cu2+‐citrate complex) was used in quantification. This method is very selective, fast and inexpensive but relatively less sensitive. The calibration curve is linear in the range of 0.4–8 mmol/L with a detection limit of 0.13 mmol/L. The relative standard deviation (RSD%) for the six repeated determinations (2 mmol/L) is 1.75%. Interference studies of more than twenty common compounds, which are present in the studied samples, were carried out. Only oxalic and ascorbic acids are serious interferes and which interferences were eliminated by simple procedures. Finally, the proposed method was successfully applied in the determination of citric acid content in ORS powder and some fruit juices.
Density and Partial Molar Volumes of Binary Mixtures for the Dimethyl Ether of a Glycol + Ethanol from T = 288.15 K to T = 318.15 K
Authors: Ku Su‐Chen , Tu Chein‐Hsiun
Published: May 2015

Densities of {xCH3(OCH2CH2)vOCH3 + (1 ‐x)C2H5OH} for v = 1 − 4 at T = (288.15, 298.15, 308.15, and 318.15) K have been measured over the entire mole‐fraction range. The measurements were made by means of a vibrating‐tube densimeter. From these densities, some derived quantities, such as partial molar volumes and partial excess molar volumes have been obtained. Values of the limiting partial molar volumes and thence of the limiting partial excess molar volumes of the components have been derived. The densities can be expressed in terms of fourth‐degree polynomials with respect to the mole fraction of the glycol. The temperature has no significant effect on the partial molar volumes of the glycols with v = 3 and 4 in ethanol. These volumetric properties are discussed in terms of molecular interactions between the glycol and ethanol.
Vibrational and Rotational Excitations of Diatomic Molecules by Chirped Laser Pulses
Authors: Martin Rebekah , Kim Jung‐Hoon , Liu Wing‐Ki , Yuan Jian‐Min
Published: May 2015

After a review of the “bucket dynamics” which classically accounts for the efficiency of chirped laser pulse excitation of the vibrations of a diatomic molecule, quantum mechanical results for the dissociation of diatomic molecules by a chirped pulse followed by a second laser pulse are presented. It is demonstrated that by using a second fixed‐frequency laser, dissociation without ionization is possible which each laser by itself would not suffice to dissociate the molecules. By using a second chirped laser pulse, additional excitation and dissociation of the molecule is observed. Similar to vibrational excitation, rotational excitation of a diatomic molecule can be accomplished by using a circularly polarized chirped laser pulse. Results of our quantum mechanical calculations show that coherent control of the rotational motion of a diatomic molecule is achievable.