bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Detection of Dopamine and Uric Acid under Coexistence of Ascorbic Acid with DNA/Pt Nanocluster Modified Electrode
Authors: ZHENG Yu , LIN Xiang‐Qin 
Published: May 2008

AbstractA novel biosensor by electrochemically codeposited Pt nanoclusters and DNA film was constructed and applied to detection of dopamine (DA) and uric acid (UA) in the presence of high concentration ascorbic acid (AA). Scanning electron microscopy and X‐ray photoelectron spectroscopy were used for characterization. This electrode was successfully used to resolve the overlapping voltammetric response of DA, UA and AA into three well‐defined peaks with a large anodic peak difference (ΔEpa) of about 184 mV for DA and 324 mV for UA. The catalytic peak current obtained from differential pulse voltammetry was linearly dependent on the DA concentration from 1.1× 10−7to 3.8×10−5mol·L−1with a detection limit of 3.6×10−8mol·L−1(S/N=3) and on the UA concentration from 3.0×10−7to 5.7×10−5mol·L−1with a detection limit of 1.0×10−7mol·L−1with coexistence of 1.0×10−3mol·L−1AA. The modified electrode shows good sensitivity and selectivity.
Application of the Organic Photosensitizers Bearing Two Carboxylic Acid Groups to Dye‐Sensitized Solar Cells
Authors: ZHANG Xue‐Hua , YAO Yi‐Shan , LI Chao , WANG Wei‐Bo , CHENG Xue‐Xin , WANG Xue‐Song , ZHANG Bao‐Wen 
Published: May 2008

AbstractThree electron donor‐�� bridge‐electron acceptor (D‐π‐A) organic dyes bearing two carboxylic acid groups were applied to dye‐sensitized solar cells (DSSC) as sensitizers, in which one triphenylamine or modified triphenylamine and two rhodanine‐3‐acetic acid fragments act as D and A, respectively. It was found that the introduction of t‐butyl or methoxy group in the triphenylamine subunit could lead to more efficient photoinduced intramolecular charge transfer, thus improving the overall photoelectric conversion efficiency of the resultant DSSC. Under global AM 1.5 solar irradiation (73 mW·cm−2), the dye molecule based on methoxy‐substituted triphenylamine achieved the best photovoltaic performance: a short circuit photocurrent density (Jsc) of 12.63 mA·cm−2, an open circuit voltage (Voc) of 0.55 V, a fill factor (FF) of 0.62, corresponding to an overall efficiency (η) of 5.9%.
Mg(OH)Cl/KI as a Highly Active Heterogeneous Catalyst for the Synthesis of Cyclic Carbonates from CO2 and Epoxides under Solvent‐Free Conditions
Authors: YUAN Gao‐Qing , SHAN Yan‐Juan , JIANG Huan‐Feng , QI Chao‐Rong 
Published: May 2008

AbstractThe combination of magnesium hydroxyl chloride [Mg(OH)Cl] with KI could efficiently catalyze the coupling reaction of carbon dioxide with epoxides to give the corresponding cyclic carbonates in good to excellent yields (75.0% –98.3%) and high selectivity (99.6%) in the absence of organic solvents. The heterogeneous catalyst Mg(OH)Cl/KI could be reused at least six times almost without loss of the catalytic activity. The influence of some key factors (such as molar ratio of Mg(OH)Cl to KI, temperature, reaction time and CO2 pressure) on the reaction was also discussed.
Application of Multivariate Calibration Techniques to Simultaneous Spectrophotometric Determination of Copper and Iron Using 1‐(2‐Pyridylazo)‐2‐naphthol in AOT Micellar Solution
Authors: KARIM‐NEZHAD Ghasem , SAGHATFOROUSH Lotfali , ERSHAD Sohrab , BAHRAMI Kokab 
Published: May 2008

AbstractMultivariate calibration models (PCR and PLS) were developed for simultaneous determination of Fe(III) and Cu(II) with 1‐(2‐pyridylazo)‐2‐naphthol and AOT as chromogenic reagent and micellizing agent, respectively. In the presence of AOT the spectrum of Fe(III)‐PAN complex was shifted to higher wavelength and the overlapping with Cu‐PAN spectrum decreased. It seems that this anionic surfactant enters the structure of the Fe‐PAN complex to cause a shift in the absorption spectrum of it. The parameters controlling behavior of the systems were investigated and optimum conditions were selected. Sixteen ternary mixtures were selected as the calibration set. To select the number of factors in PCR and PLS algorithms, a cross validation method, leaving out one sample at a time, was employed. The calibration models were validated with 8 synthetic mixtures containing the metal ions in different proportions that were randomly designed. The best calibration model was obtained by using PLS regression. The method was successfully applied to simultaneous determination of copper and iron in biological samples.
Hydrogen in Porous Tetrahydrofuran Clathrate Hydrate
Authors: Mulder Fokko M. , Wagemaker Marnix , van Eijck Lambert , Kearley Gordon J. 
Published: May 2008

AbstractThe lack of practical methods for hydrogen storage is still a major bottleneck in the realization of an energy economy based on hydrogen as energy carrier.1 Storage within solid‐state clathrate hydrates,2–4 and in the clathrate hydrate of tetrahydrofuran (THF), has been recently reported.5, 6 In the latter case, stabilization by THF is claimed to reduce the operation pressure by several orders of magnitude close to room temperature. Here, we apply in situ neutron diffraction to show that—in contrast to previous reports[5, 6]—hydrogen (deuterium) occupies the small cages of the clathrate hydrate only to 30 % (at 274 K and 90.5 bar). Such a D2 load is equivalent to 0.27 wt. % of stored H2. In addition, we show that a surplus of D2O results in the formation of additional D2O ice Ih instead of in the production of sub‐stoichiometric clathrate that is stabilized by loaded hydrogen (as was reported in ref. 6). Structure‐refinement studies show that [D8]THF is dynamically disordered, while it fills each of the large cages of [D8]THF⋅17D2O stoichiometrically. Our results show that the clathrate hydrate takes up hydrogen rapidly at pressures between 60 and 90 bar (at about 270 K). At temperatures above ≈220 K, the H‐storage characteristics of the clathrate hydrate have similarities with those of surface‐adsorption materials, such as nanoporous zeolites and metal–organic frameworks,7, 8 but at lower temperatures, the adsorption rates slow down because of reduced D2 diffusion between the small cages.
Shear Viscosity of Dusty Plasma Obtained on the Basis of the Langevin Dynamics
Authors: Ramazanov T. S. , Dzhumagulova K. N. 
Published: May 2008

AbstractShear viscosity of dusty plasma was calculated on the basis of the Langevin dynamics. Shear viscosity is considered as a function of many parameters and buffer plasma pressure is among them. Complicated dependence of viscosity on plasma pressure is considered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reactions of Terphenylbismuth Dihalides with KSi(SiMe3)3, K2Si2(SiMe3)4 and Na2[Fe(CO)]4: Reduction vs. Metathesis (Eur. J. Inorg. Chem. 16/2008)
Authors: Wolf Robert , Fischer Jelena , Fischer Roland C. , Fettinger James C. , Power Philip P. 
Published: May 2008

AbstractThe cover picture shows a bismuth crystal that has a similar shape to the molecular structure of the (dibismuthene)iron complex [Fe(CO)4(Bi2Ar′2)] [Ar′ = C6H3‐2,6‐(C6H3‐2,6‐iPr2)], the first compound with a three‐membered Bi2Fe ring. The new complex was obtained from the 1:1 reaction of Na2[Fe(CO)4] and Ar′BiCl2. In a similar vein, the double‐bonded dibismuthene Ar′2Bi2 and the single‐bonded dibismuthane Ar′2Bi2Cl2 were isolated from attempted metathesis reactions of Ar′BiCl2 with K2Si2(SiMe3)4 and KSi(SiMe3)3, respectively. Details are presented in the article by P. P. Power et al. on p. 2515 ff. We thank the Alexander von Humboldt Foundation, the Austrian Fonds zur Förderung der wissenschaftlichen Forschung, and the Max Kade Foundation for financial support of this work; Dr. J. Chris Slootweg is acknowledged for providing the picture of the bismuth crystal.
Recent Advances in the Chemistry of Indazoles
Authors: Schmidt Andreas , Beutler Ariane , Snovydovych Bohdan 
Published: May 2008

AbstractIndazoles are of considerable interest due to the broad variety of their biological activities. This overview summarizes structures of pharmacologically interesting indazoles published during the last decade, as well as syntheses, reactions, and functionalizations. Recent advances in the chemistry of N‐heterocyclic carbenes of indazole (indazol‐3‐ylidenes) and indazolium salts are also reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Potentiometric Iodide Selectivity of Polymer‐Membrane Sensors Based on Co(II) Triazole Derivative
Authors: Zhou Wei , Chai Ya‐Qin , Yuan Ruo , Wu Xia , Guo Jun‐Xiang 
Published: May 2008

AbstractThe 3‐amion‐5‐mercapto‐1,2,4‐triazole cobalt(II) [Co(II)AMETR] was used as a new carrier for preparing polymeric membrane selective sensor which exhibited high affinity for iodide ion. The effects of membrane composition, pH, the influence of lipophilic ion additives and plasticizer on the response characteristics of the sensor were investigated. The sensor showed a near Nernstian slope of −56.6 mV/decade for I− ion over a wide concentration range from 8.5×10−7 to 1.0×10−1 M with a low detection limit of 5.1×10−7 M. The sensor has a fast response time and could be used over a wide pH range of 2–8. The response mechanism is discussed in view of the AC impedance technique. The sensor was successfully applied to direct determination of iodide content in environmental water samples and mouth wash samples.
Employment of Electrochemical Techniques for Metallothionein Determination in Tumor Cell Lines and Patients with a Tumor Disease
Authors: Fabrik Ivo , Krizkova Sona , Huska Dalibor , Adam Vojtech , Hubalek Jaromir , Trnkova Libuse , Eckschlager Tomas , Kukacka Jiri , Prusa Richard , Kizek Rene 
Published: May 2008

AbstractIn the present paper we employed adsorptive transfer stripping technique coupled with chronopotentiometric stripping analysis for determination of metallothionein (MT) in tumor cell lines and differential pulse voltammetry Brdicka reaction for determination of MT in blood serum of patients with head and neck cancer or retinoblastoma, and of rats treated with cisplatin with respect to discuss the role of MT in formation of resistance on treatment with heavy metal based cytostatics. The cisplatin or carboplatin sensitive and resistant neuroblastoma cell lines were derived from the maternal cell line isolated from the bone metastasis of patients with neuroblastoma. Based on the results obtained it can be concluded that level of MT increases with higher dose of platinum based cytostatics at cells. Further we focused on determination of MT in blood serum of rats treated with cisplatin (two doses 1.05 mg and/or 2.1 mg of cisplatin per kg). The highest level of MT at rats treated with 1.05 mg cisplatin was determined after four hours as 4.9 μmol/L. In the case of the second experimental group the maximum was reached even after two hours of the treatment as 4.8 μmol/L. In addition we were interested in the effect of cisplatin or carboplatin treatment of patients with a tumor disease. At patients with tumor in head and neck area treated with cisplatin we observed that the level of MT was going higher due to administration of the drug. This phenomenon was observed at all patients. However at patients with retinoblastoma treated with carboplatin we observed various phenomena including decreasing, increasing or no changes in MT level. Progression of MT levels was therefore individual and probably depended on tumor resistance to carboplatin.
Determination of Electrochemical Electron‐Transfer Reaction Standard Rate Constants at Nanoelectrodes: Standard Rate Constants for Ferrocenylmethyltrimethylammonium(III)/(II) and Hexacyanoferrate(III)/(II)
Authors: Zhang Yan , Zhou Jianzhang , Lin Lingling , Lin Zhonghua 
Published: May 2008

AbstractThe most common approximation of electroneutrality is inappropriate for analyzing the voltammetric response of nanoelectrodes. Therefore, the microelectrode theory for extracting the standard rate constant k0 for electron transfer from steady‐state voltammograms is invalid for nanoelectrodes. Unlike previous approaches, we considered the influence of the interfacial potential distribution caused by the absence of electroneutrality. We estimated the magnitude of the error at low overpotential incurred as a result of ignoring the absence of electroneutrality and found that it was small. In this region, electrochemical reaction appears to be limited by the rate of electron transfer. Under these conditions, k0 can be obtained from steady‐state voltammogram data in a low overpotential region according to an approximate form of the Butler–Volmer equation. This procedure can greatly simplify analysis and calculation of the rate constant k0 at nanoelectrodes. Steady‐state voltammogram of equal‐concentration hexacyanoferrate(III)/(II) (Fe(CN)$\rm{ {_{6}^{3-}}}$/Fe(CN)$\rm{ {_{6}^{4-}})}$) and ferrocenylmethyltrimethylammonium(III)/(II) (FcTMA2+/FcTMA+) redox couples were investigated at PtIr nanoelectrodes in the presence of a support electrolyte. k0 for Fe(CN)$\rm{ {_{6}^{3-}}}$/Fe(CN)$\rm{ {_{6}^{4-}}}$ and FcTMA2+/FcTMA+ at PtIr nanoelectrodes were evaluated.
Behavior of PQQ Glucose Dehydrogenase on Prussian Blue‐Modified Carbon Electrode
Authors: Laurinavicius Valdas , Kurtinaitiene Bogumila , Stankeviciute Rasa 
Published: May 2008

AbstractGlucose sensitive biosensor containing pyrroloquinoline quinone (PQQ)‐dependent glucose dehydrogenase immobilized on Prussian blue (PB)‐modified graphite electrode was designed. Properties of the biosensor were investigated in the cathodic and anodic response detection regions. It was shown, that anodic response of the biosensor is sum of two signals: direct electron transport from reduced PQQ to the electrode and by formation of the PQQ‐oxygen‐PB‐carbon ternary complex. Cathodic response of the biosensor is based on the oxidation of the reduced PQQ by PB‐oxygen‐PB complex. Electrochemical regeneration of the enzyme does not produce free hydrogen peroxide.
Designs of Enterobacteriaceae Lac Z Gene DNA Gold Screen Printed Biosensors
Authors: Loaiza Óscar A. , Campuzano Susana , Pedrero María , Pingaron José M. 
Published: May 2008

AbstractThis paper describes specific electrochemical enterobacteriaceae lac Z gene DNA sensors based on immobilization of a thiolated 25 base single stranded probe onto disposable screen printed gold electrodes (gold SPEs). Two configurations have been evaluated. In the first one, the capture probe was attached to the electrode surface through its SH moiety, while mercaptohexanol (MCH) was used as spacer for the displacement of nonspecifically adsorbed oligonucleotide molecules. The hybridization event between the probe and target DNA sequences was detected at −0.20 V by square‐wave voltammetry (SWV), using methylene blue (MB) as electrochemical indicator. The second genosensor configuration involved modification of gold high temperature SPEs with a 3,3′‐dithiodipropionic acid di(N‐succinimidyl ester) (DTSP) self‐assembled monolayer (SAM). Moreover, 2‐aminoethanol was used as blocking agent, and further modification with avidin allowed binding of the biotinylated enterobacteriaceae lac Z gene DNA probe. An enzyme amplified detection scheme was applied, based on the coupling of streptavidin‐peroxidase to the biotinylated complementary target, after the hybridization process, and immobilization of tetrathiafulvalene (TTF) as redox mediator atop the modified electrode. The amperometric response obtained at −0.15 V after the addition of hydrogen peroxide was used to detect the hybridization process. Experimental variables concerning sensors composition and electrochemical transduction were evaluated in both cases. A better precision and reproducibility in the fabrication process, as well as a higher sensitivity were achieved using the biotinylated probe‐based sensor configuration. A limit of detection of 0.002 ng/μL was obtained without any preconcentration step.
Stability analysis for real‐time pseudodynamic and hybrid pseudodynamic testing with multiple sources of delay
Authors: Mercan Oya , Ricles James M. 
Published: May 2008

AbstractReal‐time pseudodynamic (PSD) and hybrid PSD test methods are experimental techniques to obtain the response of structures, where restoring force feedback is used by an integration algorithm to generate command displacements. Time delays in the restoring force feedback from the physical test structure and/or the analytical substructure cause inaccuracies and can potentially destabilize the system. In this paper a method for investigating the stability of structural systems involved in real‐time PSD and hybrid PSD tests with multiple sources of delay is presented. The method involves the use of the pseudodelay technique to perform an exact mapping of fixed delay terms to determine the stability boundary. The approach described here is intended to be a practical one that enables the requirements for a real‐time testing system to be established in terms of system parameters when multiple sources of delay exist. Several real‐time testing scenarios with delay that include single degree of freedom (SDOF) and multi‐degree of freedom (MDOF) real‐time PSD/hybrid PSD tests are analyzed to illustrate the method. From the stability analysis of the real‐time hybrid testing of an SDOF test structure, delay‐independent stability with respect to either experimental or analytical substructure delay is shown to exist. The conditions that the structural properties must satisfy in order for delay‐independent stability to exist are derived. Real‐time hybrid PSD testing of an MDOF structure equipped with a passive damper is also investigated, where observations from six different cases related to the stability plane behavior are summarized. Throughout this study, root locus plots are used to provide insight and explanation of the behavior of the stability boundaries. Copyright © 2008 John Wiley & Sons, Ltd.
Pre‐operative inflammatory markers and the risk of postoperative delirium in elderly patients
Authors: Lemstra Afina W. , Kalisvaart Kees J. , Vreeswijk Ralph , van Gool Willem A. , Eikelenboom Piet 
Published: May 2008

AbstractObjectivePathophysiological mechanisms leading to delirium are not clear. Age is a known risk factor and hypothesised to be accompanied by a low‐grade inflammatory state. Previous studies have shown an association between delirium and circulating proinflammatory markers in acutely ill and postoperative patients. In light of the ageing/inflammation theory, we investigated the association of these markers with delirium in not acutely ill, elderly patients.MethodsIn a prospective nested case‐control study levels of C‐reactive protein (CRP), interleukin 6 (Il‐6), insulin growth factor 1 (IGF‐1) were measured pre‐operatively in elderly patients admitted for hip‐surgery. These levels were compared between patients who later developed a post‐operative delirium and patients who did not. Patients were matched for age and disease severity.ResultsEighteen patients who developed delirium post‐operatively were matched with 50 controls. Median APACHE‐scores were below 16 in both groups. Pre‐operative serum concentrations of CRP, Il‐6 and IGF‐1 did not differ between groups. IL‐6 levels were associated with a measure of cognitive impairment.ConclusionIn the present study no relationship was found between levels of pre‐operative circulating pro‐inflammatory markers and post‐operative delirium in elderly patients, who were free from acute or severe disease. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of explanations on prospective applicants reactions to firm diversity practices
Authors: Williamson Ian O. , Slay Holly S. , Shapiro Debra L. , Shivers‐Blackwell Sheryl L. 
Published: May 2008

AbstractDrawing on the recruitment, marketing, and explanation literatures, we examine how the language used to describe diversity practices in employee recruitment advertisements influences the organizational attractiveness perceptions of white, black, and Asian prospective applicants. Results show that prospective applicants' reactions to advertised support for identity‐conscious diversity practices were moderated by applicants' race, applicants' previous discrimination experiences, and the type of explanation a firm used to support its use of diversity practices. The results of this article provide new insights into how firms can effectively attract a diverse applicant pool. © 2008 Wiley Periodicals, Inc.
Beyond diversity training: A social infusion for cultural inclusion
Authors: Chavez Carolyn I. , Weisinger Judith Y. 
Published: May 2008

AbstractContemporary organizations, in an effort to reap the benefits of a diverse workforce, continue to spend millions of dollars on diversity training despite the tendency of such training to either fail or result in less than desired outcomes. We introduce an alternative, strategic approach to organizational diversity designed to create a more inclusive “culture of diversity.”This long‐term, relational approach emphasizes an attitudinal and cultural transformation, requiring managers to “break barriers” by moving away from “managing diversity” toward “managing for diversity” to capitalize on the unique perspectives of a diverse workforce. © 2008 Wiley Periodicals, Inc.
Diversity—Making space for everyone at NASA/Goddard Space Flight Center using dialogue to break through barriers
Authors: Wong Sharon 
Published: May 2008

AbstractDiversity is perhaps one of the most important concepts in today's business environment. Organizations have expended significant resources in this area in an effort to improve the bottom line, to become an employer of choice, to avoid lawsuits, and to “do the right thing.” Diversity is also one of the most difficult initiatives to implement in organizations because there are such diverse views on what diversity is and how deeply it should be woven into an organization's culture. Diversity can be difficult also because the dimensions of diversity are closely tied to an individual's personal beliefs, perceptions, and life experiences. These personal beliefs often present barriers to full inclusion and participation in the workforce. At NASA/Goddard, we are using dialogue and other initiatives to break through these barriers to create and sustain an equitable and inclusive workplace. Our Diversity Dialogue Project has been key in helping us to identify and address the diversity issues and concerns at the Center and in helping us to move confidently toward the future. This article describes the diversity journey at NASA/Goddard thus far and provides insight into the challenges and opportunities of such a journey.
Vitamin K and rheumatoid arthritis
Authors: Okamoto Hiroshi 
Published: May 2008

AbstractVitamin K2 [menaquinone‐4 (MK‐4)] has been reported to induce apoptosis in hepatocellular carcinoma, leukemia, and MDS cell lines. The effects of MK‐4 on the development of arthritis have never been addressed so far. In this study, we investigated the effect of MK‐4 upon the proliferation of rheumatoid synovial cells and the development of arthritis in collagen‐induced arthritis (CIA). We analyzed the effect of MK‐4 on the proliferation of fibroblast‐like synoviocytes (FLSs) using the3‐(4,5‐demethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The proapoptotic effect of MK‐4 upon FLS was investigated with annexin V staining and DNA fragmentation and caspase 3/7 assays. Moreover, we analyzed the effect of MK‐4 on the development of CIA in female dark agouti rats. Our results indicated that MK‐4 inhibited the proliferation of FLS and the development of CIA in a dose‐dependent manner. We concluded that MK‐4 may represent a new agent for the treatment of RA in the setting of combination therapy with other disease‐modifying antirheumatic drugs. © 2008 IUBMB IUBMB Life, 60(6): 355–361, 2008