bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of N‐hexane inhalation on the enantioselective pharmacokinetics and metabolism of verapamil in rats
Authors: Mateus Fabiano H. , Lepera José S. , Marques Maria Paula , Boralli Vanessa B. , Lanchote Vera L. 
Published: February 2009

AbstractVerapamil (VER) is commercialized as a racemic mixture of the (+)‐(R)‐VER and (−)‐(S)‐VER enantiomers. VER is biotransformed into norverapamil (NOR) and other metabolites through CYP‐dependent pathways. N‐hexane is a solvent that can alter the metabolism of CYP‐dependent drugs. The present study investigated the influence of n‐hexane (nose‐only inhalation exposure chamber at concentrations of 88, 176, and 352 mg/m3) on the kinetic disposition of the (+)‐(R)‐VER, (−)‐(S)‐VER, (R)‐NOR and (S)‐NOR in rats treated with a single dose of racemic VER (10 mg/kg). VER and NOR enantiomers in rat plasma was analyzed by LC‐MS/MS (m/z = 441.3 > 165.5 for the NOR and m/z 455.3 > 165.5 for the VER enantiomers) using a Chiralpak® AD column. Pharmacokinetic analysis was performed using a monocompartmental model. The pharmacokinetics of VER was enantioselective in control rats, with higher plasma proportions of the (−)‐(S)‐VER eutomer (AUC0−∞ = 250.8 vs. 120.4 ng/ml/h; P ≤ 0.05, Wilcoxon test). The (S)‐NOR metabolite was also found to accumulate in plasma of control animals, with an S/R AUC0−∞ ratio of 1.5. The pharmacokinetic parameters AUC0−∞, Cl/F, Vd/F, and t1/2 obtained for VER and NOR enantiomers were not altered by nose‐only exposure to n‐hexane at concentrations of 88, 176, or 352 mg/m3 (P > 0.05, Kruskal‐Wallis test). However, the verapamil kinetic disposition was not enantioselective for the animals exposed to n‐hexane at concentrations equal to or higher than the TLV‐TWA. This finding is relevant considering that the (−)‐(S)‐VER eutomer is 10–20 times more potent than R‐(+)‐VER in terms of its chronotropic effect on atrioventricular conduction in rats and humans. Chirality 2010. © 2009 Wiley‐Liss, Inc.
Why are Cold Molecules so Hot?
Authors: Friedrich Bretislav , Doyle John M. 
Published: February 2009

AbstractBrrrr! Cold molecule and cold atom research are juxtaposed and the challenges in cooling and trapping molecules are recounted. Both indirect and direct techniques of producing cold and slow molecules (such as buffer‐gas cooling and magnetic trapping, see picture) are described. Advanced techniques of manipulating cold or slow molecules are reviewed and ongoing work with cold molecules is outlined.magnified imageHerein, we aim to show why the work on translationally (and otherwise) cold molecules has sparked so much inspiration—and anticipation—in both the physics and chemistry communities. We begin by discussing the basic features of cold molecules as implied by their de Broglie wavelengths, large compared with molecular dimensions. We juxtapose cold molecule and cold atom research and recount the challenges that had to be met if molecules were to be cooled and trapped. Subsequently, both the indirect and direct techniques of producing cold and slow molecules are described in some detail, and their applicability to various classes of molecules is discussed. Advanced techniques of manipulating cold or slow molecules are illustrated by the examples of DC and AC trapping and storage. Finally, ongoing and future work with cold and/or trapped molecules is outlined. This includes precision spectroscopy, chemical reaction dynamics, simulations of few‐ and many‐body physics, quantum computing, and tests of fundamental physics.
Direct Synthesis of a Photoactive Inorganic–Organic Mesostructured Hybrid Material and its Application as a Photocatalyst
Authors: Corma Avelino , Navarro Maria T. , Rey Fernando , Ruiz Violeta R. , Sabater Maria J. 
Published: February 2009

AbstractA direct route: Silylated triphenylmethanol is incorporated into mesoporous material MCM‐41 through a direct synthesis method. Under acidic conditions, this inorganic–organic hybrid generates trityl cations to give the photoactive material Tyl‐MCM41. Tyl‐MCM41 promotes the photosensitized dimerization of 1,3‐cyclohexadiene with an unprecedented selectivity towards the formation of the exo product (see scheme).magnified imageA photoactive, hexagonally structured mesoporous material (Tyl‐MCM41) is produced through co‐hydrolysis of SiO2 and a trialkoxysilane‐functionalized trityl cation as photoactive species. The formation of the corresponding triphenylmethanol precursor in the material is confirmed by spectroscopic techniques. The hybrid material has an ordered structure with a narrow pore size distribution typical of ordered mesoporous MCM‐41‐type materials. The triarylcarbinol molecules incorporated into this hybrid structure (Triphol‐MCM41) generate trityl cations under acidic conditions, which are photoactive and able to promote the photosensitized dimerization of 1,3‐cyclohexadiene in a heterogeneous solid–liquid system. The material is stable and can be recycled without loss of the photochemical activity.
Self‐Propelled Polymer Nanomotors
Authors: Tao Yu‐Guo , Kapral Raymond 
Published: February 2009

AbstractPolymer conformations: The picture shows instantaneous conformations of product molecules produced in a catalytic reaction at the head of a polymer chain. The extended (left) and collapsed (right) polymers correspond to chains in good and poor solvent conditions, respectively. The product molecule concentration gradient leads to a directed force on the polymer, so that it functions as a self‐propelled nanomotor.magnified image
Structure, Dynamics and Optical Properties of Fluorescent Proteins: Perspectives for Marker Development
Authors: Nienhaus G. Ulrich , Wiedenmann Jörg 
Published: February 2009

AbstractGlow in the dark: Fluorescent proteins of the GFP family (see picture) are key tools for life sciences research. Recent structure–dynamics–function studies have yielded new insights that aid in the rational development of advanced fluorescent marker proteins. These new markers should further extend the range of possible applications.magnified imageGFP‐like proteins, originally cloned from marine animals, are genetically encoded fluorescence markers that have become indispensable tools for the life sciences. The search for GFP‐like proteins with novel and improved properties is still ongoing, however, driven by the persistent need for advanced and specialized fluorescence labels for cellular imaging. Overall, the structures of these proteins are similar, but considerable variations have been found in the covalent structures and stereochemistry of the fluorophore, which govern essential optical properties such as the absorption/emission wavelengths. Moreover, as the fluorophore‐enclosing cavity forms its solvation shell, it can also have a significant effect on the absorption/emission wavelengths and the brightness of the fluorophore. Most exciting are recent developments of photoactivatable fluorescence markers which change their color and/or intensity upon irradiation with light of specific wavelengths. A detailed understanding of the structure and dynamics of GFP‐like proteins greatly aids in the rational engineering of advanced fluorescence marker proteins. Herein, we review our present knowledge of the structural diversity of GFP‐like proteins and discuss how structure and dynamics govern their optical properties, with an emphasis on red fluorescent proteins.
Mode‐Selective Promotion and Isotope Effects of Concerted Double‐Hydrogen Tunneling in Porphycene Embedded in Superfluid Helium Nanodroplets
Authors: Vdovin Alexander , Waluk Jacek , Dick Bernhard , Slenczka Alkwin 
Published: February 2009

AbstractIntramolecular double‐hydrogen tunneling in porphycene (see picture) is investigated. Low‐temperature conditions are ensured by doping of single molecules into superfluid helium nanodroplets. The investigation of fluorescence excitation and dispersed emission spectra and the highly dissipative environment allows the observation of mode‐selective tunneling splitting and reveals a purely concerted tunneling mechanism for all isotopic variants of porphycene.magnified image
An exploration of self‐complexity in individuals experiencing auditory hallucinations
Authors: Bell Virginia , Wittkowski Anja 
Published: February 2009

AbstractLinville's self‐complexity (SC) theory suggests that reduced SC exacerbates the effects of stress, thereby creating a vulnerability to psychopathology. This exploratory study investigated SC in individuals experiencing auditory hallucinations. Twenty‐two clinical participants experiencing auditory hallucinations were recruited from inpatient and outpatient services. Twenty‐two control participants, matched on age and gender, were recruited from non‐clinical settings. All participants completed a card sort task relating to the self, and questionnaires of affect, self‐esteem and recent stress. Although groups did not differ in unitary SC, clinical participants displayed significantly reduced positive SC (pos‐SC) compared with controls. Pos‐SC was positively correlated with increased psychological well‐being, while negative SC was inversely related, across both groups. No stress‐buffering effects for SC were found. Findings are discussed with respect to previous literature, and clinical and research implications of the study are addressed, particularly in relation to the therapeutic potential for increasing pos‐SC in patients distressed by auditory hallucinations. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of parameter mismatches on the output waveform of an LC‐VCO
Authors: Buonomo Antonio , Schiavo Alessandro Lo 
Published: February 2009

AbstractThe effect of parameter mismatches on the output waveforms of a popular voltage‐controlled oscillator is investigated, schematizing the circuit as a system of two mutually coupled oscillators, whose describing equations are derived in a perturbation form. The circuit is studied using the method of two time‐scales showing the existence of synchronization phenomena leading in presence of mismatches to a locking frequency, which significantly differs from the natural frequencies of the tanks, and to an oscillation amplitude different from that of the symmetric case. We also show that in‐phase and quadrature oscillations at the drain nodes can be generated with a proper parameter setting. Circuit simulations confirm the presence of a synchronized oscillation, which is consistent with the prediction of the presented analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Involvement of dimethylarginine dimethylaminohydrolase‐2 in visfatin‐enhanced angiogenic function of endothelial cells
Authors: Xiao Jian , Xiao Zheng‐Jun , Liu Zhen‐Guo , Gong Huan‐Yu , Yuan Qiong , Wang Shan , Li Yuan‐Jian , Jiang De‐Jian 
Published: February 2009

AbstractBackgroundVisfatin, a new adipocytokine, was reported to promote angiogenesis. Dimethylarginine dimethylaminohydrolase (DDAH), which could regulate vascular endothelial growth factor (VEGF) expression in endothelial cells, is thought as a novel modulator of angiogenesis. The aim of the study was to investigate the role of DDAH2 in visfatin‐induced angiogenesis in human umbilical vein endothelial cells (HUVECs).Methods and ResultsVisfatin could concentration‐ and time‐dependently enhance cell migration and tube formation reflecting angiogenic capability of HUVECs. Moreover, visfatin upregulated both mRNA and protein expressions of DDAH2 and VEGF. Angiogenic effects of visfatin were attenuated by DDAH2 small interfering RNA. Visfatin‐induced protein kinase B (Akt) phosphorylation and phosphoinositide 3 kinase (PI3K) inhibitors could suppress visfatin‐induced upregulation of DDAH2 and VEGF expressions.ConclusionsTaken together, our results demonstrate that PI3K/Akt‐mediated upregulation of DDAH2 expression plays a critical role in visfatin‐promoted angiogenesis via regulating VEGF‐dependent pathway. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Characterisation of (Alkoxybenzimidazolin‐2‐ylidene)palladium Complexes: The Effect of Ancillary Ligands on the Behaviour of Precatalysts
Authors: Baker Murray V. , Brown David H. , Simpson Peter V. , Skelton Brian W. , White Allan H. 
Published: February 2009

AbstractA series of new N‐heterocyclic carbene (NHC)–palladium(II) complexes bearing electron‐rich benzimidazolin‐2‐ylidene ligands are described and structurally and spectroscopically characterised. These (benzimidazolin‐2‐ylidene)palladium complexes bear butoxy groups to increase the solubility and perhaps influence the catalytic activity by increasing the electron density around the metal centre. The effect of varying the ancillary ligands is investigated, although these ligands do not appear to significantly alter the activity of the complexes as precatalysts. Preliminary studies indicate the complexes act as precatalysts with moderate activity in the Mizoroki–Heck and Suzuki–Miyaura coupling reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis, Characterization and Catalytic Activity of New N‐Heterocyclic Bis(carbene)ruthenium Complexes
Authors: Özdemir İsmail , Demir Serpil , Gürbüz Nevin , Çetinkaya Bekir , Toupet Loïc , Bruneau Christian , Dixneuf Pierre H. 
Published: February 2009

AbstractThe reaction of RuCl2(PPh3)3 with tBuOK‐deprotonated ortho‐xylyl‐bis(N‐imidazolinium) salts 1a–d yields RuCl2(PPh3)[bis(imidazolidin‐2‐ylidene)] complexes (2a–d). Under similar conditions, [RuCl2(p‐cymene)]2 leads to the ruthenium complex 3 containing a tridentate η6‐arene‐dicarbene ligand. All synthesized compounds were characterized byelemental analysis and NMR spectroscopy, and the molecular structures of 2a, 2b and 3 were determined by X‐ray crystallography. The catalytic activity of RuCl2(PPh3)[bis(imidazolidin‐2‐ylidene)] complexes 2a–b was evaluated in the direct arylation of 2‐phenylpyridine with chlorobenzene derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis and Catalytic Application of Palladium Complexes with Picoline‐Functionalized Benzimidazolin‐2‐ylidene Ligands
Authors: Jahnke Mareike C. , Pape Tania , Hahn F. Ekkehardt 
Published: February 2009

AbstractThe picoline‐functionalized benzimidazolium salts N‐alkyl‐N′‐picolylbenzimidazolium bromide [alkyl = methyl (1), ethyl (2), n‐propyl (3), n‐butyl (4)] and the dipicoline‐functionalized benzimidazolium bromide 5 have been synthesized. Reaction of the salts 1–4 with palladium acetate leads to the formation of the palladium complexes of the type [Pd(L)2]Br2 (6–9; L = N‐alkyl‐N′‐picolylbenzimidazolin‐2‐ylidene). Subsequent reaction of these complexes with AgBF4 gave the palladium complexes 10–13. The pincer‐type palladium complex [PdBrL]Br (14, L = N,N′‐dipicolylbenzimidazolin‐2‐ylidene) was prepared by deprotonation of the benzimidazolium salt 5 with n‐butyllithium and subsequent coordination of the unstable carbene intermediate to [PdBr2cod]. The molecular structures of the benzimidazolium salts 3 and 5 and the palladium complexes 7–9 and 11 have been determined by X‐ray diffraction. The bis(carbene) palladium complexes 6–9 as well as the monocarbene pincer‐type complex 14 have been used as precatalysts in Heck‐type coupling reactions of several aryl halides with styrene and n‐butyl acrylate as olefinic substrates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Noble Reactions for the Actinides: Safe Gold‐Based Access to Organouranium and Azido Complexes
Authors: Thomson Robert K. , Graves Christopher R. , Scott Brian L. , Kiplinger Jaqueline L. 
Published: February 2009

AbstractA safe gold‐based oxidative functionalization protocol has been developed, which allows access to an assortment of uranium complexes bearing azido‐ and carbon‐functional groups. Alkyl, alkynyl, and azido complexes are accessed in a single step from commercially available or easily prepared gold complexes. This methodology works for UIII → UIV and UIV → UV oxidation. A new high yielding synthetic preparation of (Ph3P)Au‐N3 is also presented. These reactions proceed rapidly in high yields, and represent a new class of reaction for gold. This work shows that gold chemistry is not just unique for organic transformations and holds great promise for similarly advancing organometallic chemistry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
New Approach to the Synthesis of N7‐Arylguanines and N7‐Aryladenines
Authors: Keder Roman , Dvořáková Hana , Dvořák Dalimil 
Published: February 2009

AbstractThe copper‐mediated arylation of 7‐methylpyrimido[1,2‐a]purin‐10(3H)‐one (1) in dichloromethane or of N2‐(dimethylamino)methyleneguanine (2) in methanol in the presence of TMEDA as a base/ligand led to the preferential formation of 1‐aryl‐7‐methylpyrimido[1,2‐a]purin‐10(3H)‐ones (4) and 7‐aryl‐N2‐(dimethylamino)methyleneguanines (7), respectively. These compounds can be easily hydrolysed to the corresponding 7‐arylguanines. Similar arylation of N6‐(dimethylamino)methyleneadenine (15) in the presence of o‐phenanthroline instead of TMEDA afforded mainly 7‐aryladenines after hydrolysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Determination of nitroaromatic explosives residue at military shooting ranges using a sweeping‐MEKC method
Authors: Yang Ying‐Ying , Liu Ju‐Tsung , Lin Cheng‐Huang 
Published: February 2009

AbstractWe report on the application of sweeping‐MEKC, for the first time, using the Environmental Protection Agency Method 8330 stock standard (a mixture of 14 explosives). The use of a traditional MEKC mode provided the LODs (at S/N=3) ranging from 1.5 to 2.9 μg/mL for the 14 explosives standards, which were improved by as low as 3.1–6.5 ng/mL when a sweeping‐MEKC technique was used. A set of 21 soil samples were collected from surface soil at military shooting ranges located at Kinmen County in Taiwan, and the findings showed that hexahydro‐1,3,5‐trini‐tro‐1,3,5‐triazine and 2,4,6‐trinitrotoluene made up the explosives residue present at the highest concentrations. This study is very useful for determining current levels of explosives residue and as a reference for making appropriate recommendations concerning future site characterization techniques.
Effect of tannic acid on Lactobacillus plantarum wine strain during starvation: A proteomic study
Authors: Cecconi Daniela , Cristofoletti Marta , Milli Alberto , Antonioli Paolo , Rinalducci Sara , Zolla Lello , Zapparoli Giacomo 
Published: February 2009

AbstractThe molecular mechanisms involved in tannic‐acid (TA)‐mediated cell growth retardation and viability prolongation of Lactobacillus plantarum VP08 strain were evaluated by a proteomic analysis of starved cells grown in the presence of TA or glucose as carbon source. The tannase activity and the cell growth retardation as well as viability prolongation were confirmed by enzymatic assay and growing tests, respectively. In order to gain information about the effect triggered at the molecular level by TA, total proteins (extracted from starved cells grown in 250 mg/L TA, or 2 g/L glucose) were analyzed by a 2D‐PAGE/MS approach to detect differentially expressed proteins. A total of 15 spots were found to be down‐regulated and 21 up‐regulated in TA‐grown cells. The results indicate an overall impact of TA on proteins involved in some cellular and metabolic pathways: glycolysis, amino acid metabolism, translation and protein folding. The modulation of specific proteins correlates with the positive effect of TA on the survival of tannase‐positive L. plantarum.
Cloning and characterization of DNA polymerase η from Trypanosoma cruzi: Roles for translesion bypass of oxidative damage
Authors: de Moura Michelle Barbi , Fonseca Schamber‐Reis Bruno Luiz , Passos Silva Danielle Gomes , Rajão Matheus Andrade , Macedo Andréa Mara , Franco Glória Regina , Junho Pena Sérgio Danilo , Ribeiro Teixeira Santuza Maria , Machado Carlos Renato 
Published: February 2009

AbstractWe report the cloning and characterization of the DNA polymerase η gene from Trypanosoma cruzi (TcPolη), the causative agent of Chagas disease. This protein, which can bypass cyclobutane pyrimidine dimers, contains motifs that are conserved between Y family polymerases. In vitro assays showed that the recombinant protein is capable of synthesizing DNA in undamaged primer‐templates. Intriguingly, T. cruzi overexpressing TcPolη does not increase its resistance to UV‐light (with or without caffeine) or cisplatin, despite the ability of the protein to enhance UV resistance in a RAD30 mutant of Saccharomyces cerevisiae. Parasites overexpressing TcPolη are also unable to restore growth after treatment with zeocin or gamma irradiation. T. cruzi overexpressing TcPolη are more resistant to treatment with hydrogen peroxide (H2O2) compared to nontransfected cells. The observed H2O2 resistance could be associated with its ability to bypass 8‐oxoguanine lesions in vitro. The results presented here suggest that TcPolη is able to bypass UV and oxidative lesions. However the overexpression of the gene only interferes in response to oxidative lesions, possibly due to the presence of these lesions during the S phase. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Evaluation of the genotoxicity of Fusarium mycotoxin moniliformin in human peripheral blood lymphocytes
Authors: Çelik Mustafa , Yılmaz Serkan , Aksoy Hüseyin , Ünal Fatma , Yüzbaşıoğlu Deniz , Dönbak Lale 
Published: February 2009

AbstractMycotoxins are fungal secondary metabolites that can be found in contaminated food and feed. There is some evidence to suggest that certain mycotoxins may be mutagenic. Here, we investigate the genotoxicity of the mycotoxin moniliformin (MON) (3‐hydroxycyclobut‐3‐ene‐1,2‐dione) in human peripheral blood lymphocytes using chromosomal aberration (CA), sister‐chromatid exchange (SCE), and micronucleus (MN) analysis. Lymphocyte cultures were treated for 48 h with six different concentrations of MON between 2.5 and 25 μM. CA, SCE, and MN frequencies were significantly increased in a dose‐dependent manner compared with the negative control. The mitotic, replication, and cytokinesis‐block proliferation indices were not affected by treatment with MON. The results provide evidence to demonstrate that MON can exert cytogenetic effects in human cells in culture. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Particulate hexavalent chromium is cytotoxic and genotoxic to the North Atlantic right whale (Eubalaena glacialis) lung and skin fibroblasts
Authors: Li Chen Tânia , Wise Sandra S. , Kraus Scott , Shaffiey Fariba , Levine Kaitlynn M. , Thompson W. Douglas , Romano Tracy , O'Hara Todd , Pierce Wise John 
Published: February 2009

AbstractHexavalent chromium compounds are present in the atmosphere and oceans and are established mutagens and carcinogens in human and terrestrial mammals. However, the adverse effects of these toxicants in marine mammals are uncertain. Previously, we reported that North Atlantic right whales, one of the most endangered great whales, have tissue chromium levels that are high, levels that may pose a risk to the whale's health. Furthermore, the study suggested that inhalation may be an important exposure route. Exposure to chromium through inhalation is mainly because of particulate compounds. However, the toxicity of particulate chromium compounds in marine mammal cells is unknown. Accordingly, in this study, we tested the cytotoxic and genotoxic effects of particulate hexavalent chromium in primary cultured lung and skin fibroblasts from the endangered North Atlantic right whale. Cytotoxicity was measured by clonogenic survival assay, and genotoxicity was measured as production of chromosome aberrations. Particulate hexavalent chromium induced cytotoxicity and genotoxicity in a concentration‐dependent manner in both right whale lung and skin fibroblasts. Lung fibroblasts were more resistant to chromium cytotoxicity, but presented with more chromosome damage than skin fibroblasts. These data further support the hypothesis that chromium may be a health concern for the endangered North Atlantic right whale. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.