bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of charge‐transfer reaction complexes in anionic polymerization of isoprene: Quantum chemical calculations
Authors: Kalninsh K. K. , Podolsky A. F. 
Published: February 2005

AbstractA new mechanism of isoprene anionic polymerization is proposed. Its central moment is thermal electronic excitation of a living polyisoprene–isoprene complex into the quasi‐degenerate electronically excited state (S · T)1, which is of the charge (electron) transfer character. It is asserted that the probability of chemical bond formation is determined by the free valence index on carbon atoms and by the geometry of reacting complex in the excited state (S · T)1. Semi‐empirical AM1 and ab initio 6‐31G* quantum chemical calculations revealed low energies of triplet excited levels (<10 kcal/mole). Comparison of isoprene polymerization on free anions and on solvated ion pairs shows that both types of active centers produce vinyl 1,2 (4,3)‐units. Free anions generate predominantly 1,2‐units, whereas solvated ion pairs tend to form units with the 4,3‐structure. Analysis of energies of excited isoprenyl lithium + isoprene complexes shows that the formation of 1,4 (4,1)‐cis‐polyisoprene in an inert media is most preferable. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Franck–Condon and Jahn–Teller effects in the E state of (CO) molecule. Resonance and preresonance Raman study in terms of time‐dependent density functional theory: New insight into an old story
Authors: Makowski Marcin , Pawlikowski Marek T. 
Published: February 2005

AbstractFranck–Condon and Jahn–Teller effects in the E state of the croconate dianion are studied in terms of time‐dependent density functional theory (TD‐DFT) at the B3LYP/aug‐cc‐pVDZ and BP86/aug‐cc‐pVDZ levels. The results of these treatments are then used to discuss the empirical absorption, preresonance, and resonance Raman spectra associated with A → E transition in the croconate dianion. In agreement with the experiment, the computations done at the B3LYP/aug‐cc‐pVDZ level of approximation predict substantial Jahn–Teller and Franck–Condon activities of ν2 (a) = 607 cm−1 (ring‐breathing) and ν11 (e) = 526 cm−1 (ring‐bending) modes in the lowest‐energy E state of the croconate ion. The activities of the other e‐ and a‐symmetry modes were found to be quite modest. It is shown that the sizable activities of ν2 (a) and ν11 (e) modes lead to Bactrian‐like structure in the absorption corresponding to the A → E transition. Taking into account the consistencies between the electronic absorption and Raman experiments, we can convincingly argue that the double‐band shape experimentally observed in the absorption of the croconate dianion cannot be attributed to solute–solvent interactions, as was recently proposed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Triplet potential energy surface for BH2N: A DFT study
Authors: Zhang Jian‐Guo , Li Qian Shu , Zhang Shao‐Wen 
Published: February 2005

AbstractThe triplet potential energy surfaces (PES) for the isomerization and dissociation reactions of BH2N isomers was investigated using the DFT/B3LYP method of theory. Thirteen BH2N isomer species and two dissociated products were identified, in which five isomerization reactions and four dissociation pathways were found. On the triplet PES, the nonplanar trans‐iminoborane (1) can isomerize to the lowest triplet state of planar aminoboranylidene (3) and the triplet state planar borylnitrene (4) directly by two three‐membered ring transition states (TS1–3 and TS1–4), respectively. The cis‐trans isomerization of iminoborane (1 and 2) by transition state (TS1–2), the internal conversion of 1 and that of 2 by two transition states (TS1a–1b and TS2a–2b) are also considered in the triplet PES. On the other hand, the dissociation product of B–N–H (5) and H atom can be predicted by the dissociation reaction of nonplanar cis‐iminoborane (2) and a planar structure aminoboranylidene (3) with the transition state of TS2–5 and TS3–5. At the same time, the dissociation product H–B–N (6) and H atom can be predicted by the dissociation reaction of nonplanar cis‐iminoborane (2) and a planar structure borylnitrene (4) with the transition state of TS2–6 and TS4–6. By analysis of the whole potential energy surface, we can find the isomerization from planar the triplet state aminoboranylidene (3) to the triplet state planar borylnitrene (4) is not carried out in one step directly, but achieved in multistep reactions of (3)(1)(4). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Coupled‐cluster study of the equilibrium geometry and harmonic vibrational frequencies of the methyl radical
Authors: Roberto‐Neto Orlando , Chakravorty Subhas , Machado Francisco B.C. 
Published: February 2005

AbstractAccurate equilibrium geometries, harmonic vibrational frequencies, and equilibrium rotational constants of the methyl radical were computed using coupled‐cluster theory in combination with the cc‐pVnZ and cc‐pCVnZ basis sets of Dunning. Valence and all electron calculations were carried out. Using all electron correlations and CBS extrapolation, the re value is equal to 1.0758 Å, which is 0.0032 Å shorter than the experimental value of r0 (1.079 Å). The harmonic (ω1, ω2, ω3, and ω4) frequencies calculated using the CBS extrapolation differ from the experimental fundamental frequencies, respectively, by +142, +125, +21, and –82 cm−1. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Analysis of N7‐(benzo[a]pyrene‐6‐yl)guanine in urine using two‐step solid‐phase extraction and isotope dilution with liquid chromatography/tandem mass spectrometry
Authors: Chen Yi‐Lung , Wang Chien‐Jen , Wu Kuen‐Yuh 
Published: February 2005

AbstractAnalysis of urinary N7‐(benzo[a]pyren‐6‐yl)guanine (BP‐6‐N7Gua), a DNA adduct induced by benzo[a]pyrene, may serve as a risk‐associated biomarker for exposure to polyaromatic hydrocarbons (PAHs). In this study a highly sensitive and specific analytical method, incorporating on‐line sample preparation coupled with isotope‐dilution liquid chromatography and tandem mass spectrometry (LC/MS/MS), was developed to quantitate this adduct in human urine. In order to achieve accurate quantitation, 15N5‐labeled BP‐6‐N7Gua was synthesized to serve as the internal standard, and a two‐step solid‐phase extraction (SPE) procedure using C8 and SCX cartridges was used for sample cleanup. BP‐6‐7‐N7Gua was analyzed using positive ion LC/MS/MS operated in multiple reaction monitoring (MRM) mode. The [M+H]+ ions at m/z 402 and 407 and the common fragment ion of [M+H]+ at m/z 252 were monitored for quantification. The recovery of this analyte after two‐step SPE was 90%, and the limit of detection was 2.5 fmol/mL in 10 mL of urine. This highly specific and sensitive method for BP‐6‐N7Gua in urine may be applied to assess exposure to PAHs in coke‐oven workers for future molecular epidemiology studies on health effects of PAHs. Copyright © 2005 John Wiley & Sons, Ltd.
Creation of highly functional thin films using electrochemical nanotechnology
Authors: Osaka Tetsuya 
Published: February 2005

AbstractThis overview describes the results of our recent study of the application of electrochemical nanotechnology to the fabrication of magnetic recording materials, interconnects in ultra‐large‐scale integrated (ULSI) devices, energy storage materials, and on‐chip biosensors. It is important to note that electrochemical processes play significant roles in developing and fabrication such sophisticated materials and devices. In the field of magnetic recording, electrodeposition methods for preparing CoNiFe and CoFe soft magnetic thin films with a high saturation magnetic flux density were newly developed, and the significant issues for obtaining those films are highlighted. In the area of ULSI interconnects, we developed a technique using a self‐assembled monolayer (SAM) for direct bonding of the interconnect layer to SiO2, and proposed a novel electroless deposition method for fabricating a diffusion barrier layer. In the field of batteries, electrodeposited SnNi alloy was proposed as a future anode material for Li batteries, and electrochemical MEMS processes were shown to be useful for fabricating micro‐sized direct methanol fuel cells (DMFCs) as portable batteries for electronics applications. In the area of chemical sensors, we developed a new process for fabricating field effect transistors (FETs) modified with SAMs for on‐chip biosensing applications. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 346–362; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20025
Ultrafast dynamics of a solution in spatially restricted environments studied by photothermal spectroscopies
Authors: Hirose Yasushi , Yui Hiroharu , Sawada Tsuguo 
Published: February 2005

AbstractThe ultrafast dynamics of a solution in spatially restricted environments was studied by using the ultrafast transient lens (UTL) method. The UTL method is used to monitor the molecular dynamics of a solution by means of a change in the refractive index, which is advantageous for investigating the molecular dynamics of restricted systems. We investigated the photoisomerization of azobenzene derivatives in cyclodextrin nanocavities and revealed how the confinement affects the photoisomerization dynamics and yields. We also studied the relaxation dynamics of photo‐excited auramine O (AuO) in a water/aerosol‐OT/n‐heptane reversed micelle. Both the perturbed properties of the included water and the interactions between AuO and the interface of the reversed micelle strongly appeared to affect the relaxation dynamics. At the same time, we observed a change in the refractive index suggesting a structural change of the micelles in the picosecond region that could not be detected by transient absorption spectroscopy. In addition, we developed the total internal reflection UTL (TIR‐UTL) method to monitor the ultrafast molecular dynamics at the liquid interface. The relaxation dynamics of photoexcited AuO at the silica/water interface were observed with subpicosecond time resolution, and it was revealed that the interaction with the interface strongly inhibited the relaxation process. These results demonstrated the advantages of the UTL method for investigating the molecular dynamics of a solution in spatially restricted environments. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 331–345; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20026
1‐alkoxyvinyl esters: renaissance of half‐century‐old acyl donors with potential applicability
Authors: Kita Yasuyuki , Akai Shuji 
Published: February 2005

AbstractAmong the various kinds of acyl donors, the 1‐alkoxyvinyl esters have characteristic features, such as a high reactivity under nearly neutral conditions and the generation of neutral and volatile esters as single coproducts. Although their use in organic syntheses began in the middle of the 1950s, no significant progress has been seen. This is probably because the existing method of preparing alkoxyvinyl esters used toxic mercuric salts and was not totally applicable for those esters having functionalized acyl moieties.We have discovered that the use of a catalytic amount of the less toxic [RuCl2(p‐cymene)]2 effectively accelerates the addition of carboxylic acids to ethoxyacetylene to give ethoxyvinyl esters bearing a variety of functionalized acyl groups in high yields. This discovery has opened a new avenue for developing new reactions and new synthetic methodologies based on the design and use of these acyl donors with suitable functional groups. Such examples include (i) the installation of hydrophilic acyl moieties on biologically active compounds, (ii) asymmetric Pummerer‐type reactions, (iii) aromatic Pummerer‐type reactions, (iv) the lipase‐catalyzed desymmetrization of symmetrical 1,3‐diols, and (v) lipase‐catalyzed domino reactions. Future possibilities for these acyl donors are also discussed. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 363–372; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20027
Stimulus‐dependent glucocorticoid‐resistance of GM‐CSF production in human cultured airway smooth muscle
Authors: Tran Thai , Fernandes Darren J , Schuliga Michael , Harris Trudi , Landells Linda , Stewart Alastair G 
Published: February 2005

For a subpopulation of asthmatics, symptoms persist even with high doses of glucocorticoids. Glucocorticoids reduce the levels of the proinflammatory and fibrogenic cytokine, granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) produced by human cultured airway smooth muscle (ASM). We have contrasted the effects of a synthetic glucocorticoid, dexamethasone, on thrombin‐ and IL‐1α‐stimulated GM‐CSF production in human ASM cells.
Although IL‐1α stimulated three‐fold higher levels of GM‐CSF mRNA and protein compared to thrombin, dexamethasone concentration‐dependently reduced IL‐1α‐stimulated GM‐CSF more potently and to a greater extent than the response to thrombin. This pattern of glucocorticoid regulation was also observed at the GM‐CSF mRNA level and was reproduced with other glucocorticoids such as fluticasone propionate.
IL‐1α and thrombin stimulated NF‐κB‐dependent luciferase expression equally. Dexamethasone treatment reduced luciferase expression stimulated by both IL‐1α and thrombin.
The GM‐CSF mRNA half life was markedly prolonged by IL‐1α compared to thrombin. This IL‐1α‐induced GM‐CSF mRNA stability was prevented by either dexamethasone or the p38MAPK inhibitor, SB203580, neither of which influenced GM‐CSF mRNA stability in thrombin‐treated cells. Dexamethasone inhibited p38MAPK phosphorylation in IL‐1α‐stimulated ASM, whereas thrombin does not stimulate p38MAPK phosphorylation.
These data suggest that the mechanism underlying the greater potency and efficacy of glucocorticoids in reducing GM‐CSF synthesis stimulated by IL‐1α depends on inhibition of the involvement of p38MAPK‐induced increases in GM‐CSF message stability.

British Journal of Pharmacology (2005) 145, 123–131. doi:10.1038/sj.bjp.0706174
In Silico Search for Single Nucleotide Polymorphisms in Genes Important in Vitamin E Homeostasis
Authors: Döring Frank , Rimbach Gerald , Lodge John K. 
Published: February 2005

AbstractLarge inter‐individual variation exists in the response to vitamin E supplementation, and this may influence the outcome of human studies. It is our hypothesis that genetic heterogeneity is an important determinant of vitamin E homeostasis. Therefore we have performed an in silico search for single nucleotide polymorphisms (SNPs) associated with genes involved in vitamin E homeostasis. Based on function, the following genes were considered as candidates for vitamin E heterogeneity: α‐tocopherol transfer protein (TTPA), tocopherol associated protein (TAP), lipoprotein lipase (LPL), multidrug resistance protein 2 (MDR‐2), pregnane X receptor (PXR) and members of the cytochrome P450 family (CYP). Searches for coding SNPs were initiated from web based programs of the National Center for Biotechnology Information (NCBI). SNP frequencies were calculated by dividing the number of annotated coding SNPs by the number of base pairs in the open reading frame. Genes for TTPA, TAP and CYP3A5 had calculated SNP frequencies between 503 and 837 base pairs per coding SNP (bp/cSNP) and so are not highly polymorphic. In contrast, cSNP frequencies in LPL, MRP2, PXR, CYP3A4 and CYP4F2 were in the range of 100 bp/cSNP and so are highly polymorphic. Thus proteins involved in specific vitamin E binding are not highly polymorphic, may not influence inter‐individual variation and so may not be good candidates for population studies. Proteins involved in drug/lipid metabolism which indirectly influence vitamin E status are highly polymorphic, are likely to influence inter‐individual variation and so are good candidates for population studies. We suggest that future studies are aimed at addressing the role of such SNPs in vitamin E homeostasis.
IUBMB Life, 56: 615‐620, 2004
Porphyromonas Gingivalis Lipopolysaccharide‐induced Up‐regulation in Endothelin‐1 Interferes with Salivary Mucin Synthesis via Epidermal Growth Factor Receptor Transactivation
Authors: Slomiany Bronislaw L. , Slomiany Amalia 
Published: February 2005

AbstractEndothelin‐1 (ET‐1) is a 21 amino acid peptide produced from a biologically inactive big ET‐1 by the action of endothelin‐converting enzyme‐1 (ECE‐1) that acts through G protein‐coupled ETA and ETB receptors. Using mucous cells of sublingual salivary gland, we show that P. gingivalis lipopolysaccharide (LPS) inhibitory effect on salivary mucin synthesis is accompanied by a marked increase in ET‐1 generation and the enhancement in ECE‐1 activity. Inhibition of ECE‐1 with phosphoramidon led to the impedance of the LPS‐induced ET‐1 generation as well as countered the detrimental effect of the LPS on mucin synthesis. Moreover, the LPS inhibitory effect of on mucin synthesis was blocked by ETA receptor antagonist, BQ610, but not by ETB receptor antagonist, BQ788. The LPS‐induced reduction in mucin synthesis, furthermore, was countered by PD153035 (76.8%), a specific inhibitor of EGFR kinase as well as PP2 (54.7%), a selective inhibitor of tyrosine kinase Src responsible for ligand‐independent EGFR transactivation. Our findings are the first to demonstrate that P. gingivalis LPS detrimental effect on salivary mucin synthesis is intimately linked to the events controlled by EGFR transactivation, triggered by upregulation in ECE‐1, enhancement in ET‐1 production, and G protein‐coupled ETA receptor activation.
IUBMB Life, 56: 601‐607, 2004
mRNA Decay in Prokaryotes and Eukaryotes: Different Approaches to a Similar Problem
Authors: Kushner Sidney R. 
Published: February 2005

AbstractOver the past 15 years considerable progress has been made in understanding the molecular mechanisms of mRNA decay in both prokaryotes and eukaryotes. Interestingly, unlike other important biological reactions such as DNA replication and repair, many features of mRNA decay differ between prokaryotes or eukaryotes. Even when a particular enzyme like poly(A) polymerase has been conserved, polyadenylation of mRNAs in prokaryotes appears to serve a very different function than it does in eukaryotes. Furthermore, while mRNA degrading multiprotein complexes have been identified in both prokaryotes and eukaryotes, their composition and biochemical mechanisms are significantly different. Accordingly, this review seeks to provide a concise comparison of our current knowledge regarding the pathways of mRNA decay in two model organisms, the prokaryote Escherichia coli and the eukaryote Saccharomyces cerevisiae.
IUBMB Life, 56: 585‐594, 2004
3D seismic technology: the geological ‘Hubble’
Authors: Cartwright Joe , Huuse Mads 
Published: February 2005

AbstractThe proliferation of three‐dimensional (3D) seismic technology is one of the most exciting developments in the Earth Sciences over the past century. 3D reflection seismic data provide interpreters with the ability to map structures and stratigraphic features in 3D detail to a resolution of a few tens of metres over thousands of square kilometres. It is a geological ‘Hubble’, whose resolving power has already yielded some fascinating (and surprising) insights and will continue to provide a major stimulus for research into geological processes and products for many decades to come. Academic and other research institutions have a major role to play in the use of this data by exploiting the enormous volume of geological information contained in 3D seismic surveys. This paper reviews some of the recent advances in basin analysis made using the medium of 3D seismic data, focusing on the fields of structural and sedimentary geology, fluid–rock interactions and igneous geology. It is noted that the increased resolution of the 3D seismic method provided the essential catalyst necessary to stimulate novel observations and discover new geological structures such as mud diapir feeders, km‐long gas blow‐out pipes, giant pockmarks and sandstone intrusions, and to capture the spatial variability of diagenetic fronts. The UKs first impact crater was also discovered using 3D seismic data. The potential for future developments in this field of geophysical interpretation is considerable, and we anticipate that new discoveries will be made in many years to come.
Palaeogene igneous rocks reveal new insights into the geodynamic evolution and petroleum potential of the Rockall Trough, NE Atlantic Margin
Authors: Archer Stuart G. , Bergman Steven C. , Iliffe James , Murphy Craig M. , Thornton Mick 
Published: February 2005

AbstractData acquired from petroleum exploration well 164/7‐1 drilled in the UK sector of the Rockall Trough have yielded fresh insights into the igneous and thermal history of this frontier region. The well targeted a large four‐way dip closed structure of presumed Mesozoic age named ‘The Dome Prospect’. The structure is now known to have a magmatic, rather than a purely structural origin, which was the preferred pre‐well interpretation. The well encountered 1.2 km of Palaeocene age basaltic lavas, overlying Late Cretaceous mudstones which were intruded by over 70 dolerite sills ranging from <1.5‐ to 152‐m thick. 40Ar/39Ar dating of the dolerite intrusions indicates an Early Palaeocene age (63–64±0.5 Ma), which are among the oldest 40Ar/39Ar dates recognised in the North Atlantic Igneous Province. Radiometric dating of the overlying basaltic lavas proved unsuccessful, because of excessive alteration. Biostratigraphic dating of underlying and overlying sedimentary strata was utilised to constrain the age of the lavas to Late Paleocene to Early Eocene age (∼55 Ma). Despite being related to two distinct events separated by ∼8 Ma, the intrusives and extrusives are compositionally similar. The basaltic rocks from well 164/7‐1 possess Sr–Nd isotopic, major and trace‐element geochemical compositions similar to other volcanic and intrusive rocks of the British Tertiary Igneous Province and represent partial melts of both lithospheric and asthenospheric mantle associated with the proto‐Icelandic mantle plume head.Joint consideration of thermal maturity, potential fields and 3D seismic data indicate a deeper igneous body in addition to the sills encountered in well 164/7‐1. Jack‐up and arching mechanisms associated with both scales of intrusive body are believed to have developed the dome structure. The preferred interpretation is of a mafic laccolith, 17 km in diameter, ∼7 km thick, intruded at 64.5 Ma, situated ∼2.5 km below the bottom of the well. 3D thermal modelling suggests that all of Tranche 52 was thermally affected by the intrusion of the magmatic body. The thermal aureole, between 27 and 51 km in diameter, is not thought to play an important role in the hydrocarbon prospectivity of the surrounding Tranches in the NE Rockall Basin.Results show that hydrocarbon exploration prospects that are circular in map view should be interpreted with caution on volcanic continental margins. In sedimentary basins, where salt domes and shale diapirs are absent and igneous rocks prevalent, periclinal structures such as ‘The Dome Prospect’ should undergo a thorough multi‐disciplinary risk assessment.