bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary Study on Cataractous Human Lenses Using Near‐Infrared Fourier Transform Raman Spectroscopy
Authors: Huang Fu‐Yung , Ho Yuh , Hsu Ming‐Ching , Wong Fong‐Zo 
Published: May 2015

AbstractRaman vibrations of the fingerprint of aromatic amino acid residues were analyzed to study the changes of cataractous lens protein in the cortex and nucleus at various ages. Tryptophan content, analyzed by the quantification of I758/I1448 ratio, shows the damage (modification) of tryptophan residue in the nucleus is caused primarily by the formation of cataracts, not by the aging process. Microenvironmental changes of tryptophan and tyrosine were analyzed by the intensity ratios of I879/I758 and I829/I853, respectively. The decrease of the ratio of I879/I758, from 0.9 to 0.6 in the nucleus and from 0.7 to 0.6 for the cortex, reveal that more buried tryptophan residues become exposed in the cortex than in the nucleus during cataractogenesis, especially for non‐senile cataractous lenses. The ratio of I829/I853 is around 1.0 for both cortical and nuclear proteins at various ages, indicating some tyrosine residues have undergone a change in their hydrogen bonding environment. When compared to previous studies, we found that a normal (clear) lens has a higher peak at 1617 cm−1 than at 1604 cm−1, while a dense opaque or brunescent lens shows stronger intensity at 1604 cm−1 than at 1617 cm−1, suggesting the ratio of I1617/I1604 can be used to evaluate the human lens morphology.
Alcalase‐catalyzed Synthesis of Novel 2,6‐Dimethoxyhydroquinone‐3‐mercaptoacetyl‐peptide Conjugates
Authors: Chen Wen‐Fu , Jong Ming‐Chu , Chen Shui‐Tein , Sheh Leung 
Published: May 2015

AbstractSeven dipeptide and one tripeptide conjugates of the cytotoxic drug 2,6‐dimethoxyhydroquinone‐3‐mercaptoacetic acid (DMQ‐MA) conjugates were prepared successfully by an alcalase‐catalyzed reaction in alcohols, using DMQ‐MA‐X‐OMe as the acyl donor and H2N‐Y‐CONH2 as the nucleophile (where X and Y are amino acids, and amino acid/dipeptides, respectively).
Some New Radical Reactions of Xanthates
Authors: Quiclet‐Sire Béatrice , Zard Samir Z. 
Published: May 2015

AbstractXanthates are convenient precursors of a variety of radicals that can be captured in an inter‐ or intramolecular fashion. Overall, the process involves rupture of the sulfide C‐S bond and addition of the elements of the xanthate to the olefinic trap. The xanthate in the product can be used in another radical sequence or ionically modified in a great variety of ways. S‐Propargyl xanthates exhibit a special but interesting behaviour which involves a sigmatropic rearrangement to the corresponding allene and ring closure to a novel betaine.
Bisabolane Sesquiterpenes from Ligularia thyrsoidea
Authors: Liao Jian‐Chun , Zhu Qi‐Xiu , Yang Hua , Jia Zhong‐Jian 
Published: May 2015

AbstractPhytochemistry investigation of the whole plants of Ligularia thyrsoidea, has led to the isolation of five new bisabolane sesquiterpenes along with three known compounds. The structures of these new compounds were elucidated by spectroscopic methods and 2D NMR techniques.
Total Synthesis of (±)‐Boschnialactone and (±)‐Tetrahydroanhydrodesoxyaucubigenin
Authors: Chang Meng‐Yang , Lin Ching‐Han , Lee An‐Yang , Tai Huo‐Mu , Chang Nein‐Chen 
Published: May 2015

AbstractA total synthesis of (±)‐boschnialactone (1) and (±)‐tertahydroanhydrodesoxyaucubigenin (2) is described and trisubstitued cyclopentenoid 3 is a key intermediate.
Axial Ligand Effects on the Redox Reactions of Manganese Porphyrins
Authors: Chang Chi‐Hong , Cheng Shu‐Hua , Oliver Su Y. 
Published: May 2015

AbstractA systematic study for the effect of axially coordinated monovalent anions on the electrode reactions of several manganese porphyrins in acetonitrile is presented. Potential shifts of the metal‐centered reduction with changes in counterion were related to the degree of Mn(III)‐counterion interaction. In the electrochemically induced ligand exchange, perchlorate anion replaces the other anions as axial ligand coordinated to Mn(III) at oxidation potential less than the first oxidation of manganese porphyrins. Formation constants for axial ligation of OH− are calculated. One‐electron oxidation of dihydroxide coordinated manganese porphyrins generate oxomanganese(IV) porphyrin complexes electrochemically. O=MnIVOEP(OH) is more thermodynamically stable than O=MnIVTPP(OH), while O=MnIVTpFPP(OH) cannot be generated electrochemically. In the presence of styrene or cyclohexene, the absorption spectra of oxomanganese(IV) porphyrins are changed to form manganese(III) porphyrins gradually, which indicates the oxygen atom transfer from oxomanganese(IV) porphyrins to the substrates.
An Efficient Total Synthesis of (2E,4E,7R)‐Farnesa‐2,4,10‐triene from (R)‐(+)‐Citronellal
Authors: Li Jing , Liu Zuosheng , Lan Jiong , Li Yulin 
Published: May 2015

Abstract(2E,4E,7R)‐farnesa‐2,4,10‐triene(Caparratriene) (1), a novel sesquiterpene hydrocarbon with significant growth inhibitory activity against CEM leukemia cells, was first synthesized from (R)‐(+)‐citronellal (2) by employing titanium‐induced intermolecular carbonyl‐coupling as the key step. The absolute configuration of (+)‐Caparratriene was determined to be 7R.
Human and Limulus Blood: Opportunity for Development of A Medical Biotechnology Project in Taiwan
Authors: Liu Teh‐Yung , Chen Yih‐Wen , Chiou Shean‐Tai 
Published: May 2015

AbstractThe function of blood is to deliver nourishments to and remove wastes from all parts of the body. It is made up of different kinds of cells bathed in a fluid called plasma. The major cellular components of blood include (1) red blood cells for carrying oxygen to the various tissues, (2) white blood cells for providing defense against infectious agents and cancer, and (3) platelets for inducing a cascade of events leading to blood clot formation that stops bleeding. The plasma also contains numerous proteins for maintaining normal balance in our body, and include (1) clotting factors such as factor VIII, factor IX, fibrinogen, and thrombin, (2) protease inhibitors and anticoagulants that regulate the coagulation pathway, the complement system, or the fibrinolytic system, (3) immunoglobulin which are antibodies directed against different infectious agents, and (4) albumin which functions as a volume expander to maintain our blood volume and is essential when threatened with severe blood loss.The plasma of the invertebrate horseshoe crab, contains three major proteins: hemocyanin, C‐reactive protein (CRP), and α2‐macroglobulin. Hemocyanin functions as an oxygen‐carrying protein. CRP is a lectin that binds to phosphocholine of the pneumococcus C‐polysaccharide, to the chromatins of damaged cells, and to the galactose moiety of desialylated glycoprotein as a membrane‐associated protein on liver marcrophages. CRP exists, however, as a normal component of the invertebrate hemolymph. α2‐macroglobulin exhibits proteinase inhibitory activity with a broad specificity that can block the activities of protease secreted from invading microorganisms. The Limulus CRP, along with the C3 homologue α2‐macroglobulin, participates in a complement ‐ like hemolytic activity in horseshoe crab hemolymph.Whereas the vertebrate evolved to use both the innate and the adaptive immunity, the invertebrate only uses the innate immunity. The innate immunity uses germ‐line encoded receptors to recognize conserved molecular constituents of infectious microorganisms, is phylogenetically older, with some of its form presumably presents in all multicellular organisms. The adaptive immunity is mediated by highly specific antigen receptors that are distributed clonally on the two types of lymphocytes, the T‐cells and the B‐cells. Evidence has accumulated in recent years to suggest that the innate immune system provides signals that are essential for the adaptive immune response to generate information on the origin of the antigen and the type of response to be induced. This linkage invites renewed interest in the study of the innate immune system of the horseshoe crab.
On the Assignment of Anomeric Configuration
Authors: Lee Yuan C. , Lee Reiko T. 
Published: May 2015

AbstractOne of the diversities of carbohydrate structure lies in their ability to form different anomers from the monosaccharide unit. Unfortunately, the question of assignment of anomers has not been dealt with properly or accurately in most organic and biochemical textbooks and reference books. In this article, the question of assignment of anomers is examined from several different standpoints and an easy solution for this tricky problem is suggested.
Multifunctional Antiviral Poly‐DNP‐Oligonucleotides
Authors: Wang Jui Hsin , Wang Aihong , Kang Insug , Li Chih‐Chien , Silbermann Benjamin Wang 
Published: May 2015

AbstractMonofunctional, bifunctional and trifunctional poly‐2′‐(2,4‐dinitrophenyl)‐oligoribonucleotides have been designed and synthesized as inhibitors of retroviruses. These compounds are membrane‐permeable, ribonuclease‐resistant, and apparently mutation‐insensitive inhibitors of reverse transcriptases. These inhibitors have been tested for the treatment of murine leukemia as an animal model related to AIDS. Although the monofunctional inhibitor is already 100% effective for the treatment of murine leukemia, its efficacy can be increased by two orders of magnitude by introducing antisense sequences in the nucleotide backbone so that the resulting multifunctional inhibitor can also disrupt the synthesis of specific viral proteins. The entropy advantage of multifunctionality in the design of antiviral agents is discussed.
Extended Hückel Orbital Forces and the Jahn‐Teller Distortions in Molecules
Authors: Letelier Jorge Ricardo , Toro‐Labbé Alejandro , Chiu Ying‐Nan 
Published: May 2015

AbstractLinear orbital vibronic constants are calculated within the Extended Hückel formalism and used to evaluate the forces acting on the atoms along the symmetry coordinates, in a planar arrangement of four identical atoms. It is shown, from the magnitude and direction of the forces, that the high‐symmetry square planar arrangement is unstable and distorts to lower symmetry.
Chemical Characterization of Single Cells and Single Molecules
Authors: Yeung Edward S. 
Published: May 2015

AbstractAdvances in sensitive optical measurement schemes have led to the detection and the physical and chemical characterization of single biological cells and individual molecules. These technological achievements are much more than the ultimate milestone in low‐level monitoring. Potential applications include DNA sequencing at high speeds, probing microscale environments, monitoring environmental pollution, studying the variability of molecular conformations, detecting disease infection at an early stage, and devising molecular‐scale imaging probes.
Laser Detection of Reaction Products: Slicing versus Projection Techniques
Authors: Chen Kuo‐Mei 
Published: May 2015

AbstractCombining laser spectroscopy and two‐dimensional imaging technologies, researchers can execute sophisticated experiments to measure time‐resolved spatial profiles of state‐selected reactants and products of elementary chemical reactions. Besides the scalar observables, there are issues of vector correlations of reaction products which are best studied by imaging techniques. Advantages and drawbacks of various projection and slicing detection techniques are elucidated. The problem of vector correlations in concerted three‐body dissociations can be tackled by the slicing techniques and a new analysis algorithm.
On Theoretical Study of a Molecular Dimer System
Authors: Hayashi M. , Shiu Y. J. , Chang C. H. , Liang K. K. , Chang R. , Yang T. S. , Islampour R. , Yu J. , Lin S. H. 
Published: May 2015

AbstractIn this paper, the vibronic structure of a dimer system is studied both theoretically and numerically. To construct adiabatic potential surfaces and electronic and vibrational wave functions for a dimer system, the adiabatic approximation is applied to two identical molecules, each of which has two electronic states with one vibrational mode. In this scheme, the excitonic splitting results not only from the electronic coupling of two molecules, but also from the vibronic coupling in each molecule. By using the resulting wavefunctions and the corresponding energies, the absorption and fluorescence spectra are studied. The effect of temperature on these spectra is also studied.
Molecular Vibronic Structures of HDITC in Solutions Studied by Femtosecond Wavelength‐Resolved Pump‐Probe Spectroscopy
Authors: Yang T.‐S. , Vöhringer P. , Dietz W. , Scherer N. F. , Lin S. H. 
Published: May 2015

AbstractWavelength‐resolved pump‐probe measurements using 11 fs duration pulses were performed to study the vibronic structures of HDITC, a cyanine dye, in ethylene glycol. Ten vibrational modes were observed in the forms of quantum beats. The frequencies of these ten vibrational modes ranged from 135 cm−1 to 1300 cm−1. The relative potential displacements along these ten vibrational coordinates were estimated by comparison with theoretical calculations.
Dynamics of Atomic and Molecular Hydrogen Elimination from Hydrocarbons at VUV Excitation
Authors: Lin Jim J. , Harich Steve , Hwang Dennis W. , Wu Malcom S. , Lee Yuan T. , Yang Xueming 
Published: May 2015

AbstractElimination of atomic hydrogen (H) and molecular hydrogen (H2) are important elementary chemical processes in photochemistry and combustion chemistry. Recently, unique and sensitive detection techniques for atomic and molecular hydrogen detection were developed in our laboratory. Using the advanced molecular beam methods, we have studied the photodissociation of a few typical hydrocarbons at 157 nm excitation, especially their atomic and molecular hydrogen elimination processes. In this report, we will briefly describe the results from photodissociation of propane, ethylene, propyne and methanol at 157 nm excitation. These molecules represent different classes of hydrocarbons such as alkane, alkene, alkyne and alcohol. Through careful studies on differently deuterated compounds, clear pictures of selective atomic and molecular hydrogen elimination processes can be constructed for all of the above compounds. These results will help us to understand the dissociation dynamics of the small hydrocarbon molecules.
Structural and Electron Density Studies on a Chromium(IV)‐Oxo Complex [CrIV(O)(TMP)]
Authors: Lin Hsiu‐Mei , Sheu Hwo‐Shuenn , Wang Chih‐Chieh , Che Chi‐Ming , Wang Yu 
Published: May 2015

AbstractThe electron density distribution of a chromium(IV)‐oxo complex, [CrIV(O)(TMP)] (TMP = 5,10,15,20‐tetrakis‐p‐methoxyphenyl porphyrin), is investigated by molecular orbital calculation. The molecular and crystal structure of the compound is studied by x‐ray diffraction. It belongs to the space group 1 2, Z = 2, a = 14.979(4) Å, b = 9.752(3), c = 15.605(3) Å, β = 100.97(2)°, V = 2238(1) Å3, Mo Kα radiation λ = 0.7107 Å, R = 4.9%, Rw = 3.5% for 3575 observed reflections. Cr is five‐coordinated in a square pyramidal fashion with the Cr atom located 0.42 Å toward the oxo‐ligand. Deformation density maps are derived from the single point molecular orbital calculation on the basis of HF and DFT(density functional theory) calculations. The accumulation of deformation density along the C‐H, C‐C, C‐N and C‐O bonds in the porphyrin ligand is well represented. The asphericity in electron density around the Cr ion is clearly demonstrated. Natural bond orbital analysis (NBO) reveals that the Cr‐Ooxo is actually a triple‐bond character (σ2π4) and the four N of pyrrole serves as a σ‐donor to Cr. The Cr‐Npyrrole bond is essentially a dative bond d‐Orbital populations of Cr derived from both calculations are in good agreement with each other. Planar dπ‐orbital is the most populated, which is in accord with the prediction from crystal field theory. Detail bond characterization of the Cr‐L, multiple bond is discussed.
The Synthesis and Application of the Mesoporous Molecular Sieves MCM‐41 — A Review
Authors: Lin Hong‐Ping , Cheng Yah‐Ru , Lin Chung‐Rong , Li Feng‐Yin , Chen Chang‐Lin , Wong She‐Tin , Cheng Soofin , Liu Shang‐Bin , Wan Ben‐Zu , Mou Chung‐Yuan , Tang Chin‐Yuan , Lin Ching‐Yen 
Published: May 2015

AbstractWe report a “delayed neutralization” process for the preparation of highly‐ordered aluminosilicate MCM‐41 molecular sieves with high thermal and hydrothermal stability, and sharp pore size distribution. However, the structural order and pore size are dependent on the carbon chain length. In the mixture surfactant systems, the pore size of the MCM‐41 materials could be fine‐tuned. The pore size can be extended from 2.5 to 4.5 nm by adding a suitable amount of hydrocarbons. The tubular morphology of the MCM‐41 material of 0.3 to 10 micrometers diameter, where the wall consists of coaxial cylindrical pores of nanometers MCM‐41, can be obtained by careful control of the surfactant‐water content and the rate of condensation of silica. An optimum condition for automatic synthesis of the hierarchical TWT structure has been accomplished. The addition of 1‐alkanols as cosurfactant would not only improve the order of the MCM‐41 hexagonal structure but also promote the formation of micrometer‐sized hierarchical materials, for example: tubules‐within‐tubule and uniform‐sized hollow spheres of diameter 5.0 ± 1.0 μm. However, the inside of the micron spheres has intricate structures possessing various topological genus ranks. The MCM‐41 is a good supporter for Molybdenum oxide catalysts. The rate of deactivation in the catalytic reaction of ethyl‐benzene dehydrogenation to styrene increases in the order: MT< MP< SiO2. The physically mixed samples have higher catalytic activity than impregnated ones.
Palladium(II) Complexes of N‐(2‐Thienylmethylidene)aniline Derivatives
Authors: Hwang Wen‐Shu , Lai Jiun‐Hwa , Wang Dong‐Liang , Chiang Michael Y. 
Published: May 2015

AbstractCoordination reactions of N‐(2‐thienylmethylidene)aniline derivatives, L, with PdCl2 or [PdCl4]2− in ethanol yield stable complexes of the type trans‐(L)2PdCl2 with the azomethine nitrogen atoms as σ donors. These are not readily convertible to othor‐palladated complexes. An X‐ray crystallographic study of the complex (L2)2PdCl2 reveals a centrosymmetric geometry. The structure is in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 8.633(2) Å, b = 12.759(3) Å, c = 8.398(2) Å, α = 96.65(5)°, β = 111.47(5)*, γ= 101.28(6)°, and Z = 1. The final R factor is 0.043 (Rw = 0.044) for 2396 observed reflections. There is no real bonding between a thiophene sulfur atom and a central palladium ion. However, a long distance interaction between S and Pd does exist.
Synthesis, Characterizations, and Structure of Group 4 Metallocene Complexes of Some Difunctional Ligands Containing Oxygen and Sulfur Donors
Authors: Lin Show‐Jinn , Ho Yuh‐Cho , Gau Han‐Mou 
Published: May 2015

AbstractReactions of CH3OCH2CH2OH, PhOCH2CH2OH, o‐CH3OC6H4CH2OH, or PhSCH2CH2OH with Cp2ZrCl2 in the presence of NEt3 gave series monomeric complexes Cp2ZrClX (X = OCH2CH2OCH3 (1), OCH2CH2OPh (2), o‐OCH2C6H4OCH3 (3) or OCH2CH2SPh (4)). In a reaction of Cp2TiCl2 with PhSCH2CH2OH in the presence of NEt3, the complex Cp2TiCl(OCH2CH2SPh) (5) was obtained. These complexes were characterized by the 1H and 13C NMR, and the chemical shifts of the Cp rings for complexes 1–4 are nearly identical, despite differences in ligands for an indication of similar structures of these complexes around the metal center. Complex 4 crystallizes into the monoclinic P21/c space group with a = 13.806(3) Å, b = 16.394(3) Å, c = 7.838(2) Å, β = 100.85(3)° Z = 4, R = 0.029, Rw = 0.044, and Gof = 1.19. The molecular structure of complex 4 shows that the 2‐(phenylthio)ethoxide bonds to the Zr metal center through the alkoxide donor leaving the thioether donor free from coordination.
Rate Study of Samarium Diiodide Reduction of Alkyl Halides and 2‐Heptanone
Authors: Lin Tzuen‐Yeuan , Fun Ming‐Ren , Chang Shih‐Chun 
Published: May 2015

AbstractRate constants directly measured from GC‐analyzed method for SmI2 reduction of alkyl halides were obtained. The rates increase in the orders of primary, secondary, tertiary RX and RCl < RBr < RI as expected. 2‐Heptanone was chosen as the partner of alkyl halide in the samarium Barbier reaction. In the absence of HMPA, the reaction orders of alkyl halide and ketone were determined as first and zero order, respectively.
A Convenient Synthetic Approach to Newly Condensed Pyrazoloazines Based on Pyrazolo[3,4‐b]pyridine
Authors: El‐Emary Talaat I. 
Published: May 2015

AbstractThe reaction of 6‐amino‐5‐cyano‐3‐methyl‐1H‐1‐phenylpyrazolo[3,4‐b]pyridine (2) and 6,7‐dihydro‐3‐methyl‐6‐oxo‐1H‐1‐phenylpyrazolo[3,4‐b)]pyridine‐5‐carbonitrile (3) and 5‐amino‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]‐1H‐pyrazolo[4′,3′‐e]pyridine (12) with different reagents have been conducted to give newly condensed pyrazoloazines.
Skeletal Reorganization of Mercaptoacetaldehyde Dialkyl Acetal in Acid: Formation of Disulphide, 1,2‐Bis(mercapto)ethylene and 1,1,2‐Tris(mercapto)ethane Derivatives
Authors: Ong Chi Wi , Yen Sin Fei , Chou Yi Meen 
Published: May 2015

AbstractThe reaction of mercaptoacetaldehyde dialkyl acetals 1a‐c in the presence of sulfuric acid, polyphosphoric acid and zinc chloride is described. Other than the disulfide reported previously, new compounds 1,2‐bis‐(mercapto)ethylene, 1,2,3‐tris‐(mercapto)ethane and 1,2‐bis‐(mercapto)methane have been isolated for the first time.
Desilylative Oxidation of Alkyl Trimethylsilyl Ethers with Pyridinium Fluorochromate
Authors: Ho Tse‐Lok , Jana Gour Hari 
Published: May 2015

AbstractDirect conversion of alkyl trimethylsilyl ethers to carbonyl compounds is accomplished using PFC in dichloromethane at room temperature. For a similar oxidation of t‐butyldimethylsilyl ethers the PCC‐n‐Bu4NF combination may be employed.
Synthesis of Biologically Active Glycopeptides
Authors: Koeller Kathryn M. , Wong Chi‐Huey 
Published: May 2015

AbstractProtein glycosylation is an important post‐translational event; however, the role carbohydrates play in glycoprotein structure and function is poorly understood, mainly due to the difficulty associated with the synthesis of this class of molecules. This review describes the types and functions of glycopeptides found in nature and the synthesis of biologically active glycopeptides, including vaccines, antibiotics, ligands of receptors involved in signaling, and various structural motifs found in glycoproteins. The synthetic strategies described in this review cover both chemical and enzymatic methods. In addition, structural studies of synthetic glycopeptides and their mimetics, and chemoenzymatic synthesis of complex glycoproteins with well‐defined carbohydrate structure for the study of the effect of glycosylation on protein structure and function are also discussed.