bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Vitamin D3 Metabolites Using High‐Performance Liquid Chromatography or Immunoaffinity Chromatography
Authors: Shimada Kazutake , Mitamura Kuniko , Higashi Tatsuya 
Published: May 2015

AbstractOur investigation of the analysis of vitamin D3 metabolites has been reviewed. The development of high‐performance liquid chromatographic methods for the quantitative determination of 25‐hydroxyvitamin D3 3‐sulfate and 25‐hydroxyvitamin D3, which are the major circulating metabolites of vitamin D3 in human serum/plasma, has been described. The developed methods were applied to the determination of the correlation between the concentration of the sulfate and its genin in healthy subjects and patients with chronic renal failure. The development of immunoaffinity chromatography immobilizing the highly specific anti‐1,25‐dihydroxyvitamin D3 antibody for the pretreatment of radioreceptor assay of 1,25‐dihydroxyvitamin D3, which is the active metabolite of vitamin D3, is also described.
Photodissociation Spectroscopy and Dynamics of Weakly Bonded Metal Ion—Ethylene Complexes
Authors: Chen J. , Wong T.H. , Kleiber P.D. 
Published: May 2015

AbstractThe photodissociation spectroscopy of weakly bonded bimolecular complexes can give important insight into fundamental molecular interactions and dynamics. We have applied these techniques to a study of metal ion‐ethylene interactions in the Mg+(3s)‐C2H4 and Al+(3s2)‐C2H4 π‐bonded complexes. Experimental work is supported by ab‐initio electronic structure calculations. These experiments allow us to explore and compare the chemical binding, electronic structure, and nonadiabatic dissociation dynamics of these complexes.
Conformational Analysis of 1,2‐Di‐O‐Octanoyl‐Ethylene‐Glycerol During Aggregation
Authors: Lin Gialih , Lu Chun‐Ping 
Published: May 2015

AbstractConformational analysis of 1,2‐di‐O‐octanoyl‐ethylene‐glycerol during aggregation by 600 MHz 1H NMR is described. In monomeric states, 1,2‐di‐O‐octanoyl‐ethylene‐glycerol exists in 75% anti‐conformer and 25% gauche‐conformer. The first critical micelle concentration of 1,2‐di‐O‐octanoyl‐ethylene‐glycerol is calculated to be 4.5 mM. In micellar states, 1,2‐di‐O‐octanoyl‐ethylene‐glycerol exists in 25% anti‐conformer and 75%) gauche‐conformer. When the concentration is greater than 10 mM, 1,2‐di‐O‐octanoyl‐ethylene‐glycerol probably aggregates to become the larger micelle, micelle II. In the second micellar state, 1,2‐di‐O‐octanoylethylene‐glycerol only exists in gauche‐conformer.
Ironcarbonyl‐Mediated Alkene Hydroamidation of 7‐Oxabenzonorbornadiene
Authors: Sun Chia‐Hsing , Ho Tzay‐Shiou , Wang Ju‐Chun 
Published: May 2015

AbstractIron carbonyl‐mediated alkene hydroamidation of 7‐oxabenzonorbornadiene was accomplished under very mild conditions as the result of nucleophilic attack of amines on iron‐coordinating CO to produce exo‐5‐(alkylaminocarbonyl)‐7‐oxabenzobicyclo[2.2.1]hept‐2‐ene derivatives.
Diterpenoids from Isodon Eriocalyx
Authors: Chen Neng‐Yu , Tian Min‐Qing , Wu Rui , Sun Han‐Dong , Li Chao‐Ming , Lin Zhong‐Wen 
Published: May 2015

AbstractTwo new diterpenoids, Maoecrystal U and epi‐maoecrystal P, together with nine known diterpenoids and eight other known compounds were isolated from Isodon eriocalyx ( ). The structures of two new diterpenoids were elucidated as 6β‐acetoxy‐15β‐hydroxy‐3α,20‐epoxy‐ent‐kaur‐16‐ene‐1,7‐dione and 16(S)‐methoxymethy‐6β,7β‐dihydroxy‐7α,20‐epoxy‐ent‐kaur‐2,3‐ethenylene‐1,15‐dione on the basis of spectroscopic evidence, especially by 2D NMR techniques.
Phytochemical and Pharmacological Studies on Chinese Paeonia Species
Authors: Ding Hsiou‐Yu , Lin Hang‐Ching , Teng Che‐Ming , Wu Yang‐Chang 
Published: May 2015

AbstractA new monoterpene glycoside, mudanpioside J (3), was isolated from the root cortex of Paeonia suffruticosa. Its structure has been established on the basis of spectral evidence. In addition, six known compounds, campesterol (4), 4‐hydroxyacetopenone (5), kaempferol (6), 3‐hydroxy‐4‐methoxybenzoic acid (7), hederagenin (8) and galloylpaeoniflorin (9) were also isolated. A screening test of monoterpene glycosides and aromatic acids derived from P. suffruticosa and P. lactiflora on arachidonic acid, thrombin, collagen and PAF induced rabbit platelet aggregation suggests aromatic acids may play an important role in inhibition of platelet aggregation, inflammation and hemorrhage due to bacterial infection.
Epoxy Type Inhibitors of Cholesterol Esterase, Acetylcholinesterase, and Butyrylcholinesterase
Authors: Lin Gialih , Kao Bing‐Hong 
Published: May 2015

AbstractEpoxy type inhibitors, 3‐t‐butylphenyl 3‐1,2‐epoxybutyl ether (1), 3‐t‐butylphenyl 3‐1,2‐epoxyhexyl ether (2), and 2‐naphthyl 3‐1,2‐epoxyhexyl ether (3) are synthesized as the active site‐directed inhibitors of cholesterol esterase, acetylcholinesterase, and butyrylcholinesterase. All epoxy compounds are characterized as the time‐independent inhibitors for all three enzymes from the stopped‐time assay. Further, all epoxy compounds are characterized as the competitive inhibitors for all three enzymes from the Lineweaver‐Burk plots. The inhibition constants (Ki) of cholesterol esterase for compounds 1‐3 are 320 ± 40, 190 ± 20, 130 ± 20 μM, respectively. The Ki values of acetylcholinesterase for compounds 1‐3 are 490 ± 20, 141 ± 5, 200 ± 30 μM, respectively. Values of Ki of butyrylcholinesterase for compounds 1‐3 are 250 ± 30, 26 ± 4, 120 ± 20 μM, respectively. Compound 2 is the most potent inhibitor for butyrylcholinesterase probably because the compound mimics most the natural substrate, butyrylcholine.
Selective Monolithiation of 1,1‐Dibromoferrocene Applied to the Synthesis of New Unsymmetrical 1,1‐Disubstituted Ferrocenyl Ligands
Authors: Dong Teng‐Yuan , Ho Pei‐Hau , Chang Chung‐Kay 
Published: May 2015

AbstractA novel convenient method for preparing unsymmetrical 1,1′‐disubstituted ferrocenyl ligands by using the readily accessible 1,1′‐dibromoferrocene as a precursor is described. The method is of interest for modifying the chelating ferrocenyl ligands in view of the growing influence of homogeneous catalysis in organic synthesis, manipulation of materials and production of high optical yield.
Conformational Analysis of Biphenyl Derivatives. I. A Novel Steric Constant from the Internal Rotation Rate of 2,2′‐Bis‐(N‐Substituted Carbamoylmethyl)Biphenyl by Means of Dynamic NMR
Authors: Lin Gialih , Hwang Ching‐Ing , Chouhwang Ju‐Yueh , Tsai Hou‐Jen 
Published: May 2015

AbstractA novel scale of steric substituent constant EsD is defined from the correlation of the logarithms of the internal rotation rate (kr) at 393 K with Hancock (Esc) steric constant by means of dynamic NMR. In the inhibition of Pseudomona species lipase by 2,2′‐bis‐(N‐substituted carbamoylmethyl)biphenyls (1‐8), the logarithms of bimolecular rate constants are multiply correlated with both the Taft substituent constant σ* and EsD.
Molecular Distance‐Edge Vector (μ) and Chromatographic Retention Index of Alkanes
Authors: Liu Shushen , Liu Hailing , Xia Zhining , Cao Chenzhong , Li Zhiliang S. 
Published: May 2015

AbstractA new method of quantitative structure‐retention relationship (QSRR) is proposed for estimating and predicting gas chromatographic retention indices of alkanes by using a novel molecular distance‐edge vector, called μ vector, containing 10 elements. The QSRR model (Ml), between the μ vector and chromatographic retention indices of 64 alkanes, was developed by using multiple linear regression (MLR) with the correlation coefficient being R = 0.9992 and the root mean square (RMS) error between the estimated and measured retention indices being RMS = 5.938. In order to explain the equation stability and prediction abilities of the M1 model, it is essential to perform a cross‐validation (CV) procedure. Satisfactory CV results have been obtained by using one external predicted sample every time with the average correlation coefficient being R = 0.9988 and average RMS = 7.128. If 21 compounds, about one third drawn from all 64 alkanes, construct an external prediction set and the 43 remaining construct an internal calibration set, the second QSRR model (M2) can be created by using calibration set data with statistics being R = 0.9993 and RMS = 5.796. The chromatographic retention indices of 21 compounds in the external testing set can be predicted by the M2 model and good prediction results are obtained with R = 0.9988 and RMS = 6.508.
Determination of Mercury and Thallium in Seawater by Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry
Authors: Liu Hung‐Wei , Jiang Shiuh‐Jen 
Published: May 2015

AbstractElectrothermal vaporization inductively coupled plasma mass spectrometry (ETV‐ICP‐MS) has been applied to the determination of Hg and Tl in seawater samples. Various modifiers were tested for the best signal of these elements. After preliminary studies, 0.3% EDTA, 0.1%m/vTAC and 1% v/v HCl were added to the sample solution to work as the modifier. Since the sensitivities of Hg and Tl in various seawater matrices and aqueous standard solutions were quite different, standard addition method and isotope dilution method were used for the determination of Hg and Tl in these seawater samples. This method was applied to the determination of Hg and Tl in NASS‐4 and CASS‐3 reference seawater samples and seawater samples collected from the Kaohsiung area. Results obtained by isotope dilution method and method of standard additions agreed satisfactorily. Detection limits were in the range of 5‐15 and 0.4‐0.5 ng l−1 for Hg and Tl in seawater, respectively, with the ETV‐ICP‐MS method. The precision between sample replicates was better than 18%) for all the determinations.
Thermal Degradation Studies of Complexes of a Derivative of Phenhomazine (Dibenzo[b,f][1:5]diazocine‐6:12‐Dione (PHZD)) by Thermoanalytical Techniques
Authors: Saeed‐ur‐Rehman  , Arshad Muhammad , Ahmad Masood , Masud Khalid , Ghani Abdul , Arshad Nasima , Qureshi Ammad Hussain , Ghauri Sohail Akhtar 
Published: May 2015

AbstractSome of the bis‐complexes of a derivative of phenhomazine (dibenzo[b,f][1:5]diazocine‐6:12‐dione; PHZD) with Ni(II), Cu(II), Co(II), Cd(II), Zn(II) and Hg(II) of the general formula M(PHZD)2X2 [where X = C1, Br and I], were prepared and identified. These complexes have been characterised on the basis of elemental analysis, and spectroscopic, magnetic and conductance data. The thermal mode of decomposition and thermal stability of these complexes was investigated on the basis of the respective thermal curves in a static air atmosphere. The thermoanalytical investigations indicate that these complexes undergo two‐step changes as temperature is raised, except for Cd(II) and Hg(II) complexes, with the formation of metal oxides as end product. The degradation mechanism of the complexes has also been proposed.
Synthesis and Spectral Behaviour of Some New Uninuclear Pyrimidine 2[2(4)]‐Mono(Tri)‐Methine Cyanine Dyes
Authors: Shindy H. A. , El‐Aal R. M. Abd , Koraiem A. I. M. 
Published: May 2015

AbstractNew unsymmetrical 2[2(4)]‐mono‐and tri (substituted tri)‐methine cyanine dyes incorporating 1,2,5,6‐tetrahydro‐4,6‐diaryl pyrimidine (pyrimidinium‐1‐yl salt)‐2‐one were prepared. Structural determination was carried out by elemental analysis, IR and 1H NMR spectral data. The spectral behaviour of all the synthesized cyanines was examined in 95% ethanol.
Synthesis of Propylene Diblock Copolymers via Metallocene and Borane Chemistry
Authors: Jiang George J , Hwu Jyh Ming , Lee Sheau Fang , Hsu Ming Tsunh 
Published: May 2015

AbstractAn isotactic chain end unsaturated polypropylene was prepared by the homogeneous metallocene catalyst Et(Ind)2ZrCl2 with MAO. Herein, the chain end unsaturated polypropylene proceeded the hydroboration reaction to prepare borane‐containing polypropylene. The borane‐containing polypropylene could be transformed to hydroxyl‐terminated polypropylene, PPOH. And then the polypropylene‐nylon 6 diblock copolymer, PP‐b‐NY6, was synthesized from telechelic PPOH by converting this prepolymer with toluene diisocyanate and using the resulting materials as macroactivators for anionic caprolactam polymerization. Meanwhile, this investigation used borane‐containing polypropylene and oxygen to produce free radicals at the chain end on the polypropylene. Experimental results indicate that the free radical is an effective initiator for the polymerization of methyl methacrylate to produce diblock PP‐b‐PMMA. The block copolymers are characterized by IR, NMR, and DSC analyses. The diblock copolymer is a good compatibilizer for polymer blends.
Phytochemical and Pharmacological Studies on Chinese Changzhu
Authors: Ding Hsiou‐Yu , Wu Yang‐Chang , Linc Hang‐Ching 
Published: May 2015

AbstractIn addition to twelve known compounds including triterpenoids, steroids, sesquiterpenoids and polyacetylenes, a new natural product, hinesolone was isolated from the rhizhome of Atractylodes chinensis (Compositae). The structure of hinesolone was elucidated on the basis of spectral evidence. Of the isolated compounds, only β‐Eudesmol showed a diuretic effect on S.D. rats.
New Meroditerpenoids from a Taiwanese Marine Sponge Strongylophora Durissima
Authors: Shen Ya‐Ching , Hung Meng‐Chieh , Prakash Chaturvedula V. S. , Wang Jeh‐Jeng 
Published: May 2015

AbstractIn addition to strongylophorines 1 (3), 2 (4), 3 (5) and 8 (6), two new meroditerpenoids named strongylophorines 9(1) and 11 (2) were isolated from a Taiwanese marine sponge Strongylophora durissima. The structures of the new compounds were established by spectral methods and chemical derivatizations.
Remarkably Fast Deprotection of Semicarbazones and Tosylhydrazones Under Mild, Neutral and Solvent‐Free Conditions
Authors: Bandgar Babasaheb P. , Makone Sangita S. 
Published: May 2015

AbstractRapid and selective regeneration of carbonyl compounds from their semicarbazones and tosylhydrazones was carried out using hexamethylenetetramine‐bromine (HMTAB) and N‐bromosuccinimide (NBS). Good to excellent yields, mild, neutral and solvent‐free conditions are important features of this method.
Ultrafast Reaction Dynamics in Different Environments
Authors: Flachenecker Günter , Materny Arnulf 
Published: May 2015

AbstractWe review recent work done on the femtosecond time‐resolved investigation of the influence of solvation on elementary molecular and reaction dynamics of solvated molecules. Using the photo dissociation reaction of I2 and NaI molecules as models, the solvation effect is studied for varying environments. By adding inert gases (He, Ar, N2) at pressures ranging from 0 to 3000 bar, the dynamics is studied starting from isolated molecules, going steadily to solvent‐like conditions. Clearly different reaction behaviour can be found when comparing I2 and NaI. While I2 molecules predissociate due to the collisions with the surrounding gas particles and afterwards recombine due to the caging effect, NaI is stabilized in its adiabatic potential well formed by the first excited electronic state and the ionic ground state. I2 is also embedded in a solid matrix, formed by a crystalline porosil. For I2 in both cases the recombination dynamics is studied by varying the probe wavelength. The experimental data are discussed using a theoretical model. For I2 in a high pressure gas environment, geminate primary and secondary recombination can be detected; in the porosils also nongeminate processes contribute on a very short time scale.
Interplay of Exciton Transfer and Relaxation
Authors: Barvík Ivan , Macek Jan 
Published: May 2015

AbstractWe have contrasted several methods which can be obtained from the Tokuyama‐Mori approach only by serious approximations treating exciton transfer as well as relaxation in the simplest model, namely symmetric molecular dimer. We have solved dynamical equations of motion for the density matrix p of the exciton interacting with a bath. The bath has been simulated by phonons in an infinite linear chain. An exciton‐phonon interaction has been taken as the local, linear and weak one. The exciton transfer runs in microscopic “SLE like” models without (mSLE) and with (mSLEr) relaxation slower and, on the other hand, in the Redfield (RE) model with the secular approximation quicker than in the Tokuyama‐Mori (TM) model. Relaxation between extended states + and ‐ is for models mSLEr and RE quicker than in the TM model.
Vibrational Motion of Electron Donor‐Acceptor Complexes Time‐Resolved by Femtosecond Fluorescence Spectroscopy
Authors: Rubtsov Igor V. , Yoshihara Keitaro 
Published: May 2015

AbstractThe excited‐state dynamics of several electron donor‐acceptor complexes were studied by a femtosecond fluorescence up‐conversion technique. The spontaneous fluorescence decay of the complexes contains an oscillatory component superimposed with an ultrafast decay component. The oscillatory component was assigned to the out‐of‐plane vibration of the acceptors (tetracyanoethylene (TCNE), chloranil, fluoranil) having b3u symmetry. The time‐dependent fluorescence spectrum for the TCNE ‐ hexamethylbenzene (HMB) complex was reconstructed from the fluorescence dynamics at different wavelengths and the fluorescence peak‐shift correlation function was obtained. The ultrafast relaxation of the fluorescence peak position is superimposed with the oscillatory component. The main component of the spectral relaxation of 115 fs is attributed mainly to the intramolecular vibrational energy redistribution process in both donor and acceptor parts of the complex. The oscillatory behavior of the fluorescence peak position demonstrates the modulation of the transition frequency during the vibrations. The time dependence of the mean transition moment was constructed. It oscillates with the same frequency (155 cm−1), which is an indication of the non‐Condon transition. Thus, two mechanisms are observed to be responsible for the oscillations: the modulation of the transition frequency and the modulation of the mean transition moment by the vibrational motion.
Ultrafast Anisotropy Measurements on Charge Transfer Dynamics in Plastocyanin
Authors: Nakashima Satoru , Seike Kazushige , Nagasawa Yutaka , Okada Tadashi , Sato Maki , Kohzuma Takamitsu 
Published: May 2015

AbstractUsing a blue copper protein, plastocyanin, we have studied protein dynamics associated with optical excitation of the charge‐transfer band of plastocyanin by ultrafast pump‐probe measurements. In this study we show the first clear evidence of a coherency of the protein motion that is induced by the charge‐transfer reaction. The formerly observed low‐frequency vibrational mode (33 cm−1) is attributed to the coherent motion of the protein by the anisotropy measurement. In this charge‐transfer reaction, not only stochastic process, but coherent motion of protein is revealed to play a key role in the reaction.
Solvent Dependent Ultrafast Ground State Recovery Dynamics of Triphenylmethane Dyes
Authors: Nagasawa Yutaka , Ando Yoshito , Okada Tadashi 
Published: May 2015

AbstractWe have studied ground state recovery dynamics of triphenylmethane dyes, brilliant green and malachite green, by a single wavelength pump‐probe spectroscopy at 635 nm with a time‐resolution of 33 fs. The recovery of the ground state dependeded on solvent viscosity and also on solute molecular size. We observed a plateau or a rise component in the signal which indicates an intermediate state. The rise time also showed solvent viscosity dependence even in the ultrafast time domain, although no solute dependence was observed. It is suggested that the lack of solute dependece indicates that only small conformational change is involved in the initial process.
Ultrafast Fragmentation and Vibrational Dynamics of Triatomic Hetero‐ and Homonuclear Alkali Metal Clusters
Authors: Rosendo‐Francisco Porfirio , Lupulescu Cosmin , Baptist Bernd , Vajda ŠTefan 
Published: May 2015

AbstractThe one‐color femtosecond pump and probe spectroscopical technique was employed to study the fragmentation kinetics and vibration dynamics of the dissociative excited states of alkali trimer clusters K2Na, K3 and Na2K located in the spectral region between 730 and 840 nm. The electronically excited states were populated by a pump pulse via one‐photon absorption. The temporal evolution of the excited state was then monitored by ionizing the particle at a variable delay with a two photon transition. The lifetimes of the predissociated excited states strongly depend on the excitation wavelengths: 2.8‐5.1 ps for K2Na, 7.5‐9.8 ps for K3, and 2.5‐5.8 ps for Na2K. Furthermore, the dominant fragmentation channels were identified as well. In the case of the Na2K trimer a clear wavepacket dynamics with an oscillation period of about 490 fs was observed at an excitation wavelength of 770 nm. In the case of the K3 and K2Na trimers, no pronounced oscillatory ion signal indicative of a vibrational dynamics was observed at the applied wavelength region.
Formation of Bacteriochlorophyll Anion Band at 1020 nm Produced by Nuclear Wavepacket Motion in Bacterial Reaction Centers
Authors: Yakovlev A. G. , Shuvalov V. A. 
Published: May 2015

AbstractFormation of a nuclear wavepacket on the potential energy surface of the primary electron donor P* induced by 30‐fs excitation of pheophytin‐modified Rhodobacter sphaeroides R‐26 reaction centers leads to a reversible and irreversible appearance of the state P+BA− monitored by the measurements of the 1020‐nm band which is characteristic of the radical anion band of bacteriochlorophyll monomer BA−. The reversible appearance of the state P+BA− is characterized by two (130 and 320 cm−1) vibration modes and related to the creation of maximal value of the Franck‐Condon factor when the wavepacket is near an intersection of the P* and P+BA− potential energy surfaces. The irreversible formation of the state P+BA− with a time constant of 3 ps is accompanied by oscillations with frequencies of 9 and 33 cm−1. These results show that the nuclear vibration modes (9 and 3 3 cm−1) on the P* potential energy surface have near their bottom the intersection with the P+BA− surface as well. The electron transfer time between P* and BA was estimated to be in the range of 700 fs. This is larger than the wavepacket intersection time for the 130 cm−1 mode (∼100 fs) and comparable with that for the 33 cm−1 mode (∼600 fs). Therefore the reversible electron transfer with small amplitude can be observed for the 130 cm−1 mode, while the irreversible one is allowed for the 33 cm−1 mode that is probably important for the primary charge separation.
Models of Ultrafast Energy and Electron Transfers in Bacterial Reaction Centers
Authors: Hayashi Michitoshi , Yang Tzyy‐Schiuan , Liang Kuo‐Kan , Chang Chung‐Hung , Lin Sheng Hsien 
Published: May 2015

AbstractIn this paper, we present a microscopic model to describe the spectroscopy and dynamics for photosynthetic bacterial reaction centers (RCs). In this model, we propose eight vibrational modes and their Huang‐Rhys factors for different electronic energy states, and the couplings between the electronic states. As applications, we have constructed steady state and ultrafast time‐resolved spectra for the mutant RC of Rhodobacter (Rb.)sphaeroides R26. Our model can also treat the temperature effect on the spectroscopy and dynamics of RCs.