bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Enantiopure 1‐r‐Alkyl‐2‐c,5‐t‐Diphenylphospholanes and Phospholanium Salts through Direct Alkylation of Phospholane
Authors: Dobrota Cristian , Duraud Amelie , Toffano Martial , Fiaud Jean‐Claude 
Published: April 2008

AbstractChiral enantiopure 1‐alkyl‐2,5‐diphenylphospholanium salts were obtained in one step through alkylation of phospholane with alkyl triflates. The resulting air‐stable phosphonium salts are electron‐rich trialkylphosphane precursor ligands for transition metals, and they offer a convenient route toward chiral quaternary phosphonium salts as phase‐transfer agents.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Development of a Novel Automatic Potentiometric System for Determination of Selenium and Its Application in Pharmaceutical Formulations and Anodic Slime
Authors: Kamel Ayman H. , Elnaby Eman H. , Kelany Ali E. 
Published: April 2008

AbstractPoly(vinyl chloride) polymeric membrane sensors containing Sn(IV) phthalocyanine dichloride (SnPC) and Co(II) phthalocyanine (CoPC) as novel electroactive materials dispersed in o‐nitrophenyl octylether (o‐NPOE) as a plasticizer are examined potentiometrically with respect to their response toward selenite (SeO32−) ions. Fast Nernstian response for SeO32− ions over the concentration ranges 7.0×10−6–1.0×10−3 and 8.0×10−6–1.0×10−3 mol L−l at pH 3.5–8.5 with lower detection limit of 5.0×10−6 and 8.0×10−6 mol L−1 and calibration slopes of −25.4 and −29.7 mV decade−1 are obtained with SnPC and CoPC based membrane sensors, respectively. The proposed sensors reveals by the modified separate solution method (MSSM) a good selectivity over different anions which differ significantly from the classical Hofmeister series. A segmented sandwich membrane method is used to determine complex formation constants of the ionophores in situe in the solvent polymeric sensing membranes. Membrane incorporating CoPC in a tubular flow detector is used in a two channels flow injection set up for continuous monitoring of selenite at a frequency of ca. 50 samples h−1. Direct determination of selenium in pharmaceutical formulations and anodic slime gives results in good agreement with data obtained using standard ICP method.
Voltammetric Determination of Methimazole Using a Carbon Paste Electrode Modified with a Schiff Base Complex of Cobalt
Authors: Shahrokhian Saeed , Ghalkhani Masoumeh 
Published: April 2008

AbstractThe electrochemical behavior of methimazole, as an antithyroid agent, is investigated on the surface of a carbon‐paste electrode modified with a newly synthesized Schiff base complex of cobalt. The prepared modified electrode showed an efficient catalytic role in the electrochemical oxidation of methimazole, leading to remarkable decrease in oxidation overpotential and enhancement of the kinetics of the electrode reaction. The mechanism of the electrocatalytic process on the surface of the modified electrode is analyzed by obtaining the cyclic voltammograms in various potential sweep rates and pHs of the buffer solutions. The differential pulse voltammetry is applied as a very sensitive analytical method for the determination of sub‐micromolar amounts of methimazole. A linear dynamic range of 1×10−6 to 1×10−4 M with a detection limit of 5×10−7 M is resulted for methimazole. The modified electrode is successfully applied for the accurate determination of methimazole in pharmaceutical and clinical preparations. The linear range in calibration curves remains constant in addition to tablet preparations of methimazole and also in spiking to the synthetic human serum samples. In comparison to calibration curves in background buffer solution, the slope of the curves showed a variation less than 3% in determinations in background solutions of tablet and human synthetic serum samples. These results showed high efficiency of the Voltammetric procedure for accurate determination of methimazole in drug and clinical preparations. The modified electrode can be prepared very easy and renewed in its surface by simple polishing. The reproducibility of the electrode response, based on ten measurements during two month, was 3.2% for the slope of the calibration curve.
A Novel Electrochemical DNA Biosensor Fabricated with Layer‐by‐Layer Covalent Attachment of Multiwalled Carbon Nanotubes and Gold Nanoparticles
Authors: Ma Haiyan , Zhang Liping , Pan Yan , Zhang Keying , Zhang Yuzhong 
Published: April 2008

AbstractA novel DNA biosensor has been fabricated for the detection of DNA hybridization based on layer‐by‐layer (LBL) covalent assembly of gold nanoparticles (GNPs) and multiwalled carbon nanotubes (MWCNTs). The stepwise LBL assembly process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The hybridization events were monitored by differential pulse voltammetry (DPV) measurement of the intercalated doxorubicin, and the factors influencing the performance of the DNA hybridization was investigated in detail. The signal was linearly changed with target DNA concentration increased from 0.5 to 0.01 nM, and had a detection limit of 7.5 pM (signal/noise ratio of 3). In addition, the DNA biosensor showed an excellent reproducibility and stability under the DNA‐hybridization conditions.
Simultaneous Determination of Nickel and Cadmium by Adsorptive Stripping Voltammetry
Authors: Gholivand M. B. , Bahrami S. , Abbasi S. , Sohrabi A. 
Published: April 2008

AbstractA sensitive and fast method for the simultaneous determination of trace amounts of nickel and cadmium in real samples has been described using differential pulse adsorptive stripping voltammetry (DPASV) by adsorptive accumulation of the N,N′‐bis(salicylaldehydo)4‐carboxyphenylenediamine (BSCPDA)–complex on the hanging mercury drop electrode (HMDE). As supporting electrolyte 0.02 mol L−1 ammonia buffers containing ligand has been used. Optimal analytical conditions were found to be: BSCPDA concentration of 42 μM, pH 9.6 and adsorption potential at −50 mV versus Ag/AgCl. With an accumulation time of 20 s, the peaks current are proportional to the concentration of nickel and cadmium over the 1–180, and 0.5–200 ng mL−1 with detection limits of 0.06 and 0.03 ng mL−1 respectively. The sensitivity of method for determination of nickel and cadmium were obtained 0.54 and 0.98 nA mL ng−1, respectively. The procedure was applied to simultaneous determination of nickel and cadmium in some real and synthetic artificial samples with satisfactory results.
Simultaneous Determination of Acetaminophen and Ascorbic Acid at an Unmodified Boron‐Doped Diamond Electrode by Differential Pulse Voltammetry in Buffered Media
Authors: Radovan Ciprian , Cofan Codruta , Cinghita Dan 
Published: April 2008

AbstractA boron‐doped diamond electrode (BDDE) was used for the simultaneous anodic determination of L‐ascorbic acid (AA) and acetaminophen (AC) in aqueous buffered media by differential pulse voltammetry (DPV). Linear calibration plots of anodic current peaks versus concentration were obtained for both analytes in the concentration range 0.01–0.1 mM with very high correlation coefficients. RSD of 2–3% and high sensitivities were obtained from DPV data in single and dicomponent systems. The potential applicability of the DPV technique associated with standard addition was illustrated by simultaneous determination of AA and AC in real sample solutions made up from pharmaceutical products.
Facilitated Transfer of Alkali Metal Ions by a Tetraester Derivative of Thiacalix[4]arene at the Liquid–Liquid Interface
Authors: Guler Akgemci Emine , Bingol Haluk , Ersoz Mustafa , Stibor Ivan 
Published: April 2008

AbstractThe facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28‐tetraethoxycarbonylmethoxy‐thiacalix[4]arene across the water/1,2‐dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half‐wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2‐dichloroethane interface, the facilitated transfers were observed by formation of 1 : 1 (metal:ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1 : 2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log β1°), and 8.36 (log β2°), respectively.
Pseudo‐dynamic test of a full‐scale CFT/BRB frame—Part II: Seismic performance of buckling‐restrained braces and connections
Authors: Tsai Keh‐Chyuan , Hsiao Po‐Chien 
Published: April 2008

AbstractThis paper is Part II of a two‐part paper describing a full‐scale 3‐story 3‐bay concrete‐filled tube (CFT)/buckling‐restrained braced frame (BRBF) specimen tested using psuedo‐dynamic testing procedures. The first paper described the specimen design, experiment, and simulation, whereas this paper focuses on the experimental responses of BRBs and BRB‐to‐gusset connections. This paper first evaluates the design of the gusset connections and the effects of the added edge stiffeners in improving the seismic performance of gusset connections. Test results suggest that an effective length factor of 2.0 should be considered for the design of the gusset plate without edge stiffeners. Tests also confirm that the cumulative plastic deformation (CPD) capacity of the BRBs adopted in the CFT/BRBF was lower than that found in typical component tests. The tests performed suggest that the reduction in the BRB CPD capacities observed in this full‐scale frame specimen could be due to the significant rotational demands imposed on the BRB‐to‐gusset joints. A simple method of computing such rotational demands from the frame inter‐story drift response demand is proposed. This paper also discusses other key experimental responses of the BRBs, such as effective stiffness, energy dissipation, and ductility demands. Copyright © 2008 John Wiley & Sons, Ltd.
PKC‐dependent endocytosis of the GLT1 glutamate transporter depends on ubiquitylation of lysines located in a C‐terminal cluster
Authors: González‐gonzález Inmaculada M. , García‐tardón Noemí , Giménez Cecilio , Zafra Francisco 
Published: April 2008

AbstractThe activity of the main glutamate transporter in the CNS, GLT1, can be regulated by protein kinase C (PKC). It is known that activation of PKC by phorbol esters promotes the clathrin‐dependent internalization of the transporter, followed by its lysosomal degradation. However, the molecular mechanisms that link PKC activation and the internalization of GLT1 are not fully understood. In this article, we show that this internalization process is dependent on the ubiquitylation of lysine residues located in the C‐terminal tail of GLT1. Exposure to PMA increases the ubiquitylation of GLT1 in transfected cells and in the rat brain, and this ubiquitylated GLT1 accumulates in the intracellular compartment. However, internalization of ubiquitylated GLT1 was blocked with a dominant negative dynamin 2 mutant, indicating that the addition of ubiquitin moieties to the transporter in the membrane precedes its endocytosis. The elimination of lysines from the C‐terminus of the transporter (lysines 497, 517, 526, 550, 558, 570, and 573) blocked GLT1 ubiquitylation and endocytosis. However, reintroduction of lysine 517 alone into this mutant was sufficient to restore PMA dependent ubiquitylation and internalization of GLT1. Similarly, reintroduction of lysine 526 restored the endocytosis, while this was only partially recovered after the individual reintroduction of lysines 550 or 570. These data suggest that the activation of PKC induces the ubiquitylation of these C‐terminal lysine residues in GLT1 and that this modification mediates the interaction of the transporter with the endocytic machinery. © 2008 Wiley‐Liss, Inc.
Opioid addiction and pregnancy: Perinatal exposure to buprenorphine affects myelination in the developing brain
Authors: Sanchez Emilse S. , Bigbee John W. , Fobbs Wambura , Robinson Susan E. , Sato‐Bigbee Carmen 
Published: April 2008

AbstractBuprenorphine is a μ‐opioid receptor partial agonist and κ‐opioid receptor antagonist currently on trials for the management of pregnant opioid‐dependent addicts. However, little is known about the effects of buprenorphine on brain development. Oligodendrocytes express opioid receptors in a developmentally regulated manner and thus, it is logical to hypothesize that perinatal exposure to buprenorphine could affect myelination. To investigate this possibility, pregnant rats were implanted with minipumps to deliver buprenorphine at 0.3 or 1 mg/kg/day. Analysis of their pups at different postnatal ages indicated that exposure to 0.3 mg/kg/day buprenorphine caused an accelerated and significant increase in the brain expression of all myelin basic protein (MBP) splicing isoforms. In contrast, treatment with the higher dose caused a developmental delay in MBP expression. Examination of corpus callosum at 26‐days of age indicated that both buprenorphine doses cause a significant increase in the caliber of the myelinated axons. Surprisingly, these axons have a disproportionately thinner myelin sheath, suggesting alterations at the level of axon‐glial interactions. Analysis of myelin associated glycoprotein (MAG) expression and glycosylation indicated that this molecule may play a crucial role in mediating these effects. Co‐immunoprecipitation studies also suggested a mechanism involving a MAG‐dependent activation of the Src‐family tyrosine kinase Fyn. These results support the idea that opioid signaling plays an important role in regulating myelinationin vivoand stress the need for further studies investigating potential effects of perinatal buprenorphine exposure on brain development. © 2008 Wiley‐Liss, Inc.
Adenosine induces hemeoxygenase‐1 expression in microglia through the activation of phosphatidylinositol 3‐kinase and nuclear factor E2‐related factor 2
Authors: Min Kyoung‐Jin , Kim Jong‐Hyeon , Jou Ilo , Joe Eun‐Hye 
Published: April 2008

AbstractAdenosine, a purine nucleoside, has been reported to suppress the inflammatory responses of microglia in the brain. However, the underlying mechanisms of its anti‐inflammatory action are unclear at present. Here we show that adenosine reduces the increase in intracellular reactive oxygen species (ROS) through expression of an antioxidant enzyme, hemeoxygenase‐1 (HO‐1). The H2O2‐induced intracellular ROS level was significantly low in microglia pretreated with adenosine for 3–6 h, compared with that in untreated cells. Adenosine induced HO‐1 mRNA and protein expression within 3 h, which was maintained for up to 12 h. Nuclear factor E2‐related factor 2 (Nrf2), a transcription factor, and phosphatidylinositol 3‐kinase (PI3K) and Akt pathways appear to mediate HO‐1 expression. In response to adenosine, Nrf2 translocated from the cytosol to nuclei, and bound to the antioxidant response element (ARE). Adenosine enhanced HO‐1 promoter activity in an ARE‐dependent manner. Moreover, the nucleoside stimulated Akt phosphorylation, and suppressors of PI3K (LY294002 and wortmannin) reduced adenosine‐induced HO‐1 expression. However, we propose that the effects of adenosine are independent of adenosine receptors, since agonists and antagonists of A1, A2a, and A3 had little effect on the regulation of intracellular ROS and HO‐1 expression. Our results collectively suggest that adenosine acts as an endogenous regulator of brain inflammation via modulation of microglial ROS production. © 2008 Wiley‐Liss, Inc.
Quantitative multifocal fMRI shows active suppression in human V1
Authors: Pihlaja Miika , Henriksson Linda , James Andrew C. , Vanni Simo 
Published: April 2008

AbstractMultifocal functional magnetic resonance imaging has recently been introduced as an alternative method for retinotopic mapping, and it enables effective functional localization of multiple regions‐of‐interest in the visual cortex. In this study we characterized interactions in V1 with spatially and temporally identical stimuli presented alone, or as a part of a nine‐region multifocal stimulus. We compared stimuli at different contrasts, collinear and orthogonal orientations and spatial frequencies one octave apart. Results show clear attenuation of BOLD signal from the central region in the multifocal condition. The observed modulation in BOLD signal could be produced either by neural suppression resulting from stimulation of adjacent regions of visual field, or alternatively by hemodynamic saturation or stealing effects in V1. However, we find that attenuation of the central response persists through a range of contrasts, and that its strength varies with relative orientation and spatial frequency of the central and surrounding stimulus regions, indicating active suppression mechanisms of neural origin. Our results also demonstrate that the extent of the signal spreading is commensurate with the extent of the horizontal connections in primate V1. Hum Brain Mapp, 2008. © 2008 Wiley‐Liss, Inc.
Social cognition and the brain: A meta‐analysis
Authors: Van Overwalle Frank 
Published: April 2008

AbstractThis meta‐analysis explores the location and function of brain areas involved in social cognition, or the capacity to understand people's behavioral intentions, social beliefs, and personality traits. On the basis of over 200 fMRI studies, it tests alternative theoretical proposals that attempt to explain how several brain areas process information relevant for social cognition. The results suggest that inferring temporary states such as goals, intentions, and desires of other people—even when they are false and unjust from our own perspective—strongly engages the temporo‐parietal junction (TPJ). Inferring more enduring dispositions of others and the self, or interpersonal norms and scripts, engages the medial prefrontal cortex (mPFC), although temporal states can also activate the mPFC. Other candidate tasks reflecting general‐purpose brain processes that may potentially subserve social cognition are briefly reviewed, such as sequence learning, causality detection, emotion processing, and executive functioning (action monitoring, attention, dual task monitoring, episodic memory retrieval), but none of them overlaps uniquely with the regions activated during social cognition. Hence, it appears that social cognition particularly engages the TPJ and mPFC regions. The available evidence is consistent with the role of a TPJ‐related mirror system for inferring temporary goals and intentions at a relatively perceptual level of representation, and the mPFC as a module that integrates social information across time and allows reflection and representation of traits and norms, and presumably also of intentionality, at a more abstract cognitive level. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
The cut‐off levels of CD23 expression in the differential diagnosis of MCL and CLL
Authors: Barna Gábor , Reiniger Lilla , Tátrai Péter , Kopper László , Matolcsy András 
Published: April 2008

AbstractFlow cytometric analysis of CD23 expression in CD5‐positive B‐cells is a widely applied method in the differential diagnosis of chronic lymphocytic leukaemia (CLL) and mantle cell lymphoma (MCL). According to the most accepted criteria, the leukaemic cell population is CD19/CD5/CD23 triple positive in CLL but CD23‐negative in MCL. Recently, several groups have reported CD23‐positive MCL cases; however, these studies mostly analysed only CD23 positivity but not intensity. To determine the role and the cut‐off levels of CD23 positivity and intensity in the differential diagnosis of CLL and MCL, 26 cases of MCL and 84 cases of CLL were compared using flow cytometric analysis. Our results suggest that high values of CD23 positivity (>92.5%) and/or high fluorescence intensity (>44.5 mean fluorescence intensity (MFI)) of CD23 are related to CLL, whereas low CD23 positivity (<30%) is related to MCL. However, cases with intermediate CD23 positivity (between 30 and 92.5%) and lower intensity (<44.5 MFI) can either belong to CLL or MCL. In these cases, additional tests such as FISH analysis of the translocation t(11;14) or immunohistochemical detection of cyclin D1 overexpression are required to differentiate CLL from MCL. Copyright © 2008 John Wiley & Sons, Ltd.
Lung inflammation and thrombogenic responses in a time course study of Csb mice exposed to ozone
Authors: Kooter Ingeborg M. , Frederix Kim , Spronk Henri M. H. , Boere A. John F. , Leseman Daan L. A. C. , Steeg Harry van , Cate Hugo ten , Cassee Flemming R. 
Published: April 2008

AbstractOzone is a well‐known oxidant air pollutant, inhalation of which can result in oxidative stress, and lead to pulmonary inflammation.The aim of this study was to evaluate the time‐course events after a single ozone exposure in transcription‐coupled repair defective Csb and wild type mice.Mice were exposed for 3 h to 2 ppm ozone and biological parameters related to oxidative stress and inflammation were examined in the lungs at 0, 4, 9, 24 and 48 h after exposure. In addition the procoagulant and thrombomodulin activities were explored by a combination of assays for tissue factor and thrombin generation.This study revealed a significant biological response to ozone, for both Csb and wild type mice. The onset of inflammation in Csb mice, as indicated by an increase in interleukin‐6, tumor necrosis factor‐α and total cell influx, occurred earlier compared with those seen in wild type mice. On the other hand, Csb mice showed a delayed antioxidant reaction compared with wild type mice. Both genotypes developed a procoagulant reaction characterized by a stably increased tissue factor activity and a progressive increase in thrombin generation after 2 days.These experiments have shown that ozone, a well‐known toxic substance from the environment, induces not only inflammation, but also procoagulant reactions in the lungs of mice. These results have implications for understanding the systemic effects induced by oxidant air pollutants. Copyright © 2008 John Wiley & Sons, Ltd.
Are occupational exposure limits becoming more alike within the European Union?
Authors: Schenk Linda , Hansson Sven Ove , Rudén Christina , Gilek Michael 
Published: April 2008

AbstractThe occupational exposure limits (OELs) established by seven different national regulatory agencies of EU member states are compared with those of the European Commission (EC). The comparison concerned: (1) what chemicals have been selected, (2) the average level of exposure limits for all chemicals, and (3) the similarity between the OELs of different EU member states and the OELs recommended by the European Commission. The average level of the exposure limits has declined during the past 10 years in four of the five countries in our study for which historical data were available to us. Poland has not changed its level noticeably and Germany has increased it. Since the first list of indicative OELs was established by the EC, a few of the EU exposure limits have been lowered. The similarity index indicates that the exposure limits of EU member states are converging towards the European Commission's recommended OELs. Still, the average level of OELs differs between organizations – the Estonian OELs are on average 35% higher than the Polish OELs. Copyright © 2008 John Wiley & Sons, Ltd.