bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid chromatography–mass spectrometry for analysis of a novel β2‐adrenoceptor agonist trantinterol and its metabolites in beagle dog urine
Authors: Wang Yanjuan , Lu Xiumei , Jiang Kun , Xiong Zhili , Cheng Maosheng , Li Famei 
Published: July 2009

AbstractA liquid chromatography–tandem mass spectrometry method was developed for the identification of metabolites of trantinterol, a novel β2‐adrenoceptor agonist, in beagle dog urine. The separation of metabolites was performed on a reversed‐phase C8 column using 0.1% formic acid in water and methanol (70 : 30, v/v) as the mobile phase. The structural information and elemental information of metabolites were acquired by an electrospray ionization tandem mass spectrometer and a quadrupole time‐of‐flight mass spectrometer, respectively. A total of 13 metabolites were detected and characterized on the basis of their tandem MS/MS fragmentation patterns. The accurate masses of nine metabolites were determined and two metabolites were further confirmed by comparing with reference standards. The metabolic pathways of trantinterol in beagle dog are proposed. Copyright © 2009 John Wiley & Sons, Ltd.
A wheat embryo cell‐free protein synthesis system not requiring an exogenous supply of GTP
Authors: Koga Hirohisa , Misawa Satoru , Shibui Tatsuro 
Published: July 2009

AbstractMost in vitro protein synthesis systems require a supply of GTP for the formation of translation initiation complexes, with two GTP molecules per amino acid needed as an energy source for a peptide elongation reaction. In order to optimize protein synthesis reactions in a continuous‐flow wheat embryo cell‐free system, we have examined the influence of adding GTP and found that the system does not require any supply of GTP. We report here the preparation of a wheat embryo extract from which endogenous GTP was removed by gel filtration, and the influence of adding GTP to the system on protein synthesis reactions. Using Green Fluorescent Protein (GFP) as a reporter, higher levels of production were observed at lower concentrations of GTP, with the optimal level of production obtained with no supply of GTP. A HPLC‐based analysis of the extract and the translation mixture containing only ATP as an energy source revealed that GTP was not detectable in the extract, however, 35 μM of GTP was found in the translation mixture. This result suggests that GTP could be generated from other compounds, such as GDP and GMP, using ATP. A similar experiment with a C‐terminally truncated form of human protein tyrosine phosphatase 1B (hPTP1B1‐320) gave almost the same result. The wheat embryo cell‐free translation system worked most efficiently without exogenous GTP, producing 3.5 mg/mL of translation mixture over a 48‐h period at 26°C. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
HERC1 polymorphisms: population‐specific variations in haplotype composition
Authors: Yuasa Isao , Umetsu Kazuo , Nishimukai Hiroaki , Fukumori Yasuo , Harihara Shinji , Saitou Naruya , Jin Feng , Chattopadhyay Prasanta K. , Henke Lotte , Henke Jürgen 
Published: July 2009

AbstractHuman HERC1 is one of six HERC proteins and may play an important role in intracellular membrane trafficking. The human HERC1 gene is suggested to have been affected by local positive selection. To assess the global frequency distributions of coding and non‐coding single nucleotide polymorphisms (SNPs) in the HERC1 gene, we developed a new simultaneous genotyping method for four SNPs, and applied this method to investigate 1213 individuals from 12 global populations. The results confirmed remarked differences in the allele and haplotype frequencies between East Asian and non‐East Asian populations. One of the three common haplotypes observed was found to be characteristic of East Asians, who showed a relatively uniform distribution of haplotypes. Information on haplotypes would be useful for testing the function of polymorphisms in the HERC1 gene. This is the first study to investigate the distribution of HERC1 polymorphisms in various populations. Copyright © 2009 John Wiley & Sons, Ltd.
Development of Selective Bisubstrate‐Based Inhibitors Against Protein Kinase C (PKC) Isozymes By Using Dynamic Peptide Microarrays
Authors: Poot Alex J. , van Ameijde Jeroen , Slijper Monique , van den Berg Adriënne , Hilhorst Riet , Ruijtenbeek Rob , Rijkers Dirk T. S. , Liskamp Rob M. J. 
Published: July 2009

AbstractKinase inhibitors are increasingly important in drug development. Because the majority of current inhibitors target the conserved ATP‐binding site, selectivity might become an important issue. This could be particularly problematic for the potential drug target protein kinase C (PKC), of which twelve isoforms with high homology exist in humans. A strategy to increase selectivity is to prepare bisubstrate‐based inhibitors that target the more selective peptide‐binding site in addition to the ATP‐binding site. In this paper a generally applicable, rapid methodology is presented to discover such bisubstrate‐based leads. Dynamic peptide microarrays were used to find peptide‐binding site inhibitors. These were linked with chemoselective click chemistry to an ATP‐binding site inhibitor, and this led to novel bisubstrate structures. The peptide microarrays were used to evaluate the resulting inhibitors. Thus, novel bisubstrate‐based inhibitors were obtained that were both more potent and selective compared to their constituent parts. The most promising inhibitor has nanomolar affinity and selectivity towards PKCθ amongst three isozymes.
Characterization of the Rv3377c Gene Product, a Type‐B Diterpene Cyclase, from the Mycobacterium tuberculosis H37 Genome
Authors: Nakano Chiaki , Hoshino Tsutomu 
Published: July 2009

AbstractThe Rv3377c gene from the Mycobacterium tuberculosis H37 genome is specifically limited to those Mycobacterium species that cause tuberculosis. We have demonstrated that the gene product of Rv3377c is a diterpene cyclase that catalyzes the formation of tuberculosinol from geranylgeranyl diphosphate (GGPP). However, the characteristics of this enzyme had not previously been studied in detail with homogeneously purified enzyme. The purified enzyme catalyzed the synthesis of tuberculosinyl diphosphate from GGPP, but it did not bring about the synthesis of tuberculosinol. Optimal conditions for the highest activity were found to be as follows: pH 7.5, 30 °C, MgII (0.1 mM), and Triton X‐100 (0.1 %). Under these conditions, the kinetic values of KM and kcat were determined to be 11.7±1.9 μM for GGPP and 12.7±0.7 min−1, respectively, whereas the specific activity was 186 nmol min−1 mg−1. The enzyme activity was inhibited at substrate concentrations higher than 50 μM. The catalytic activity was strongly inhibited by 15‐aza‐dihydrogeranylgeraniol and 5‐isopropyl‐N,N,N,2‐tetramethyl‐4‐(piperidine‐1‐carbonyloxy)benzenaminium chloride (Amo‐1618). The DXDTT293–297 motif, corresponding to the DXDDTA motif conserved among terpene cyclases, was mutated in order to investigate its function. The middle D295 was found to be the most crucial entity for the catalysis. D293 and two threonine residues function synergistically to enhance the acidity of D295, possibly through hydrogen‐bonding networks. The Rv3377c enzyme could also react with (14R/S)‐14,15‐oxidoGGPP to generate 3α‐ and 3β‐hydroxytuberculosinyl diphosphate. Conformational analyses were carried out with deuterium‐labeled GGPP and oxidoGGPP. We found that GGPP and (14R)‐oxidoGGPP adopted a chair/chair conformation, but (14S)‐oxidoGGPP adopted a boat/chair conformation. Interestingly, the conformations of oxidoGGPP for the A‐ring formation are the opposite of those of oxidosqualene when it is used as a substrate by squalene cyclases for the biosynthesis of hopene and tetrahymanol. (3R)‐Oxidosqualene is folded in a boat conformation, whereas (3S)‐2,3‐oxidosqualene folds into a chair conformation, for the formation of the A‐rings of the hopene and tetrahymanol skeletons, respectively.
Clinical safety and efficacy of a novel thin‐strut cobalt–chromium coronary stent system: Results of the real world Coroflex Blue Registry
Authors: Bocksch Wolfgang , Pomar Francisco , Dziarmaga Mieczyslaw , Tresukosol Damras , Ismail Omar , Janek Bronislav , Carlsson Joerg , Simon Jean‐Philippe 
Published: July 2009

AbstractObjectives: The aim of this registry was to evaluate the clinical efficacy and safety of the Coroflex Blue cobalt–chromium stent in real‐world practice. Background: The development of cobalt–chromium bare‐metal stents (BMS) with thinner struts has lead to better deliverability and lower target‐lesion revascularization rates compared with stainless steel BMS. Methods: The Coroflex Blue Registry was an international, prospective, multicenter registry enrolling patients with symptomatic ischemic heart disease attributable to single de novo or restenotic nonstented lesions of a single vessel amenable for percutaneous stenting. The primary end point was clinically driven target‐lesion revascularisation (TLR) 6 months after enrolment, secondary endpoints were technical/procedural success, in‐hospital outcome, definite stent thrombosis and major adverse cardiac events (death, myocardial infarction, or TLR) after 6 months. Results: The registry included 2,315 patients (mean age 64.3 ± 11.1 years, 19.8% diabetes, 37.3% acute myocardial infarction). Although a complex lesion cohort with 60.3% Typ B2/C‐lesions, the technical success rate was 99.1% and the procedural success rate 98.5%. The incidence of TLR after 6 months was 5.5% and the cumulative 6‐month acute/subacute stent thrombosis rate was 1.6%. After 6 months cumulative event‐free survival was 90.8% in all patients and 87% in patients with acute PCI for acute myocardial infarction. Conclusions: This registry demonstrates the safety and efficacy of the Coroflex Blue cobalt–chromium stent platform in real‐world practice. In the era of drug‐eluting stents (DES), these results raise the serious question if the use of DES for primary prevention of restenosis and TLR is really justified.
Real case virtual reality training prior to carotid artery stenting
Authors: Roguin Ariel , Beyar Rafael 
Published: July 2009

AbstractBackground: The majority of procedural training especially in interventional cardiology, still occurs on patients with direct mentoring by experienced physicians during an actual clinical procedure. In recent years there is an increase use of simulators especially for carotid artery stenting. However, most simulators use “generic” predefined cases. Methods and Result: We report here a simulation done on data of a real patient prior to intervention. The patient's specific carotid anatomy was modeled using CTA on an endovascular simulator. Pre‐procedure patient‐specific case rehearsal accurately predicted procedure experience. Conclusions: A case rehearsal prior to an intervention may be useful in the planning and execution of carotid artery stenting. The use of patient specific simulation helps with planning of procedure and device selection, and may lead to use of less contrast and radiation, and shorter procedure duration. These may benefit the patient with increased success and lower complication rates. © 2009 Wiley‐Liss, Inc.
Drug‐eluting stent fracture: Incidence, contributing factors, and clinical implications
Authors: Canan Timothy , Lee Michael S. 
Published: July 2009

AbstractStent fracture has been observed in noncoronary vessels, especially in the superficial femoral and popliteal arteries and with bare metal stents in saphenous vein grafts of coronary arteries. Since the introduction of drug‐eluting stents, stent fractures have also been reported in small studies and case reports. We reviewed these publications to assess what is known regarding the incidence, contributing factors, and clinical implications of drug‐eluting stent fracture in coronary arteries. The reported rate of drug‐eluting stent fracture in coronary arteries ranges from 1 to 8%, although much of the available literature is derived from single‐center studies that are heterogeneous in their study methods. A higher risk of stent fracture may be associated with the right coronary artery location, excessive tortuosity or angulation of the vessel, overlapping stents, and longer stents. The closed‐cell design of the Cypher stent has been associated with increased rigidity that may increase the risk of stent fracture, although these studies did not assess the overall outcomes between the Cypher and Taxus stents in a head‐to‐head comparison. Stent fracture has been shown by most studies to be associated with a statistically increased incidence of focal in‐stent restenosis, and some have shown an increased risk of target lesion revascularization. Other complications observed with stent fracture include stent thrombosis, coronary aneurysms, myocardial infarction, and sudden death. © 2009 Wiley‐Liss, Inc.
X‐Ray Photoelectron Spectroscopy and Reactivity Studies of a Series of Ruthenium Catalysts
Authors: Jarzembska Katarzyna , Seal Sudipta , Woźniak Krzysztof , Szadkowska Anna , Bieniek Michał , Grela Karol 
Published: July 2009

AbstractX‐Ray photoelectron spectroscopy (XPS) was applied to six selected ruthenium precatalysts. The XPS data obtained were compared against reactivity and structural results. The XPS data confirmed some dependencies such as the electron‐donor properties of the substituents at the ruthenium center. Additionally, the data combined with structural and reactivity results explain the differences between the character of Grubbs and Hoveyda catalysts. It was found that changing the PCy3 ligand to OiPr (PCy3=tricyclohexylphosphane, OiPr=isopropoxy) has a major influence on relative electron‐donating properties of the N‐heterocyclic carbene ligand (NHC) and PCy3 groups, which was supported by the relative charges on the Ru center for the examined compounds. Moreover, the turnover frequency (TOF) of a selected example reaction decreased when introducing a NHC group in the case of Grubbs catalysts, but increased in the case of Hoveyda‐type catalysts. The XPS data also explained the relative activity values of some catalysts (higher reactivity of nitro‐Hoveyda than Hoveyda second‐generation catalysts). However, the binding energies do not predict TOFs. Sole examination of the XPS data does not provide a base for reaching unambiguous and binding conclusions as to the relative reactivity of all the investigated systems.
Alkene Polymerization Catalysts Bearing Tridentate Phenoxyamine Ligands with sp3 C Donors
Authors: Edson Joseph B. , Keresztes Ivan , Lobkovsky Emil B. , Coates Geoffrey W. 
Published: July 2009

AbstractThe reaction of vinyl‐appended phenoxyamine 2 with tetrabenzyltitanium provided the phenoxyaminetitanium(II) alkene complex [rac‐Lig2TiBn], arising from intramolecular vinyl‐group insertion followed by toluene elimination. Whereas [rac‐Lig2TiBn] was inactive for olefin polymerization upon benzyl abstraction, treatment with ethylene led to the formation of stable titanacyclopentane complex [rac‐Lig2(CH2)2TiBn]. Alternatively, six‐membered metallacyclic complexes [rac‐Lig1ZrBn2‐a/b] and [rac‐Lig1HfBn2‐a/b] were obtained from reaction of vinyl‐appended phenoxyamine 1 with tetrabenzylzirconium or tetrabenzylhafnium in a further rare example of intramolecular vinyl‐group insertion into neutral tribenzyl group IV precursors. Living and isoselective polymerization of 1‐hexene was promoted by [rac‐Lig1HfBn2‐a/b]/B(C6F5)3 at 0 °C, whereas [rac‐Lig1ZrBn2‐a/b]/B(C6F5)3 catalyzed the living and isoselective polymerization of propylene ([m4]=0.76) at 0 °C. This catalyst system was employed for the synthesis of a diblock copolymer featuring an isotactic polypropylene semicrystalline block and poly(ethylene‐co‐propylene) amorphous block.
A nonlinear partial least squares algorithm using quadratic fuzzy inference system
Authors: Abdel‐Rahman Araby I. , Lim Gino J. 
Published: July 2009

AbstractWe introduce a new nonlinear partial least squares algorithm ‘Quadratic Fuzzy PLS (QFPLS)’ that combines the outer linear Partial Least Squares (PLS) framework and the Takagi–Sugeno–Kang (TSK) fuzzy inference system. The inner relation between the input and the output PLS score vectors is modeled by a quadratic TSK fuzzy inference system. The performance of the proposed QFPLS method is tested and compared against four other well‐known partial least squares methods (Linear PLS (LPLS), Quadratic PLS (QPLS), Linear Fuzzy PLS (LFPLS), and Neural Network PLS (NNPLS)) on various different types of randomly generated test data. QFPLS outperformed competitors based on two comparison measures: the output variables cumulative per cent variance captured by the PLS latent variables and the root mean‐square error of prediction (RMSEP). Copyright © 2009 John Wiley & Sons, Ltd.
Ligand Recognition Processes in the Formation of Homochiral C3‐Symmetric LnL3 Complexes of a Chiral Alkoxide
Authors: Arnold Polly L. , Buffet Jean‐Charles , Blaudeck Robert , Sujecki Slawomir , Wilson Claire 
Published: July 2009

AbstractThe reaction of a chiral racemic bidentate ligand HL1 (tBu2P(O)CH2CH(tBu)OH) with mid to late trivalent lanthanide cations affords predominantly homochiral lanthanide complexes (RRR)‐[Ln(L1)3] and (SSS)‐[Ln(L1)3]. A series of reactions are reported that demonstrate that the syntheses are under thermodynamic control, and driven by a ligand ‘self‐recognition’ process, in which the large asymmetric bidentate L1 ligands pack most favourably in a C3 geometry around the lanthanide cation. The synthesis of bis(L1) adducts [Ln(L1)2X] (X=N(SiMe3)2, OC6H3tBu‐2,6) is also reported. Analysis of the diastereomer mixtures shows that homochiral (L1)2 complexes are favoured but to a lesser extent. The complexes Ln(L1)3 and [Ln(L1)2(OC6H3tBu‐2,6)] have been studied as initiators for the polymerization of ε‐caprolactone and its copolymer with lactide, glycolide and its copolymer with lactide, and ε‐caprolactam.
The Formation of Large‐Area Conducting Graphene‐Like Platelets
Authors: Salvio Riccardo , Krabbenborg Sven , Naber Wouter J. M. , Velders Aldrik H. , Reinhoudt David N. , van der Wiel Wilfred G. 
Published: July 2009

AbstractThe treatment of a suspension of graphite oxide (GO) with sodium azide leads to a material that, after reduction, features amino groups at the top and bottom of the sheets. These groups react through microcontact printing with an isothiocyanate monolayer on a silicon oxide substrate to form covalent bonds that strongly attach to the particles on the surface. With ultrasonication it is possible to obtain exfoliation of the sheets that are not covalently bound to the surface leaving single‐layer platelets attached to the substrate. The azido derivative can be also used to functionalize the graphene oxide with long alkylic chains through a click chemistry approach. This functionalization results in the exfoliation of this material in dimethylformamide. The novel materials were fully characterized by different techniques including IR spectroscopy, thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM and TEM), X‐Ray photoelectron spectroscopy (XPS), and solid state NMR spectroscopy. The material with amino groups, after the reduction step, is conductive with a resistivity only approximately seven times larger than that of unprocessed graphite. This implies that after reduction of the GO, the conjugated sp2 network is largely restored. We consider this to be an important step towards a chemical approach for forming conducting large‐area platelet films of single‐layer graphene.
Seeking the Chemical Roots of Darwinism: Bridging between Chemistry and Biology
Authors: Pross Addy 
Published: July 2009

AbstractChemistry and biology are intimately connected sciences yet the chemistry–biology interface remains problematic and central issues regarding the very essence of living systems remain unresolved. In this essay we build on a kinetic theory of replicating systems that encompasses the idea that there are two distinct kinds of stability in nature—thermodynamic stability, associated with “regular” chemical systems, and dynamic kinetic stability, associated with replicating systems. That fundamental distinction is utilized to bridge between chemistry and biology by demonstrating that within the parallel world of replicating systems there is a second law analogue to the second law of thermodynamics, and that Darwinian theory may, through scientific reductionism, be related to that second law analogue. Possible implications of these ideas to the origin of life problem and the relationship between chemical emergence and biological evolution are discussed.
Regio‐ and Stereoselectivity in the Decatungstate Photocatalyzed Alkylation of Alkenes by Alkylcyclohexanes
Authors: Dondi Daniele , Ravelli Davide , Fagnoni Maurizio , Mella Mariella , Molinari Alessandra , Maldotti Andrea , Albini Angelo 
Published: July 2009

AbstractTetrabutylammonium decatungstate (WO) photocatalyzes radical alkylation reactions starting directly from alkanes. When using tert‐butylcyclohexane and methylcyclohexane as the radical precursors, the addition to electrophilic alkenes (β,β‐dialkylmethylenemalononitriles, acrylonitrile, methyl acrylate, methyl vinyl ketone) is regioselective and exclusively gives 3‐ and 4‐substituted cyclohexyl adducts, with no significant functionalization of the other positions. Furthermore, when a β,β‐disubstituted alkene is used, the reaction is stereoselective (cis stereochemistry for the 1,3‐cyclohexane derivatives and trans for the 1,4 isomers). Some of the reactions have also been carried out by using benzophenone as the photocatalyst, giving the same product distribution. However, the decatungstate anion is a superior catalyst from a preparative point of view, because it is efficient at low concentrations (0.002 m, 2 mol %) and allows for a simple work up. From a mechanistic point of view, the role of both the alkyl radicals and the radical adducts has been assessed by trapping experiments in the presence of suitable additives (α‐phenyl‐N‐tert‐butylnitrone, PBN, and 2‐methyl‐2‐nitrosopropane, MNP) and by EPR spectroscopic detection of the resulting nitroxides in solution. Furthermore, trapping by the nitroxide TEMPO (TEMPO=2,2,6,6‐tetramethylpiperidine N‐oxide) gives O‐(tert‐butylcyclohexyl)hydroxylamines, again as only the 3‐ and the 4‐substituted isomers. We conclude that the observed regioselective activation originates from the initial hydrogen abstraction step (the statistically corrected ratio for positions 3 and 4 ranges from 1.1 to 1.35 for all of the trapping products). The selectivity is mainly due to steric hinderence.
Electrochemical Properties and Computations of Stable Radicals of the Heavy Group 14 Elements (Si, Ge, and Sn)
Authors: Becker James Y. , Lee Vladimir Ya. , Nakamoto Masaaki , Sekiguchi Akira , Chrostowska Anna , Dargelos Alain 
Published: July 2009

AbstractA series of stable radicals centered on persilyl‐substituted heavy Group 14 elements, (tBu2MeSi)3E. (E=Si, Ge, Sn), was studied by cyclic voltammetry in different solvents to determine their first oxidation and reduction potentials and to compare their ease of oxidation and reduction with known experimental and computed ionization energies (Ei) and electron affinities (Eea), respectively. It has been observed that all of the first oxidation and reduction potentials for the three radicals studied are irreversible in o‐dichlorobenzene (o‐DCB), whereas the reduction waves are quasi‐reversible in THF. A good correlation has been found between measured oxidation potentials and ionization energy values, but no correlation between reduction potentials and electron affinity values was found, probably due to kinetic and surface effects.