bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perceived political self‐efficacy: Theory, assessment, and applications
Authors: Caprara Gian Vittorio , Vecchione Michele , Capanna Cristina , Mebane Minou 
Published: February 2009

AbstractPolitical efficacy is addressed within the framework of social cognitive theory and a new measure to assess perceived political self‐efficacy is presented. Three studies document the validity of the new scale of measurement. The first study (N = 1673) examined the psychometric properties of the scale in accordance with classical test theory. This led to the identification of a unidimensional factor structure, including perceived political self‐efficacy in promoting one's own political opinion, in sustaining the political programs of the party to which one belongs, and in monitoring one's own political representatives' commitment. The second study (N = 632) further confirmed the internal and construct validity of the scale; criterion validity was also investigated using several indicators of political interest and participation. The third study (N = 1176) showed that politicians holding offices have higher levels of perceived political self‐efficacy than partisans and voters, further corroborating the criterion validity of the scale. Copyright © 2009 John Wiley & Sons, Ltd.
Theoretical and Experimental Study of the Homogeneous Catalytic Oxidation of Nicotinamide Adenine Dinucleotide (NADH) at Spherical Gold Electrodes Using Linear Sweep Voltammetry and Chronopotentiometry
Authors: Molina Ángela , González Joaquín , López‐Tenés Manuela , Soto Carmen M. 
Published: February 2009

AbstractThe homogeneous catalytic oxidation of coenzyme nicotinamide adenine dinucleotide (NADH) with dopamine at a thiolactic acid modified gold spherical electrode of radius 0.0128 cm has been studied in aqueous phosphate media (pH 7.0) using linear sweep voltammetry and chronopotentiometry with power time and exponential time currents. We have proved that, under the conditions of this study, the steady state is reached, in such a way that the expressions for the I−E and dI/dE−E responses are simplified and become independent of time and the electrochemical technique employed. Therefore, the experimental I−E and dI/dE−E curves obtained in chronopotentiometry and linear sweep voltammetry are practically superimposable and, from easy expressions for the peak parameters of the dI/dE−E curves deduced in this paper, values of the chemical and electrochemical rate constants have been obtained.
Fabrication of a Highly Sensitive Glucose Biosensor Based on Immobilization of Osmium Complex and Glucose Oxidase onto Carbon Nanotubes Modified Electrode
Authors: Salimi Abdollah , Kavosi Begard , Hallaj Rahman , Babaei Ali 
Published: February 2009

AbstractIn this research a novel osmium complex was used as electrocatalyst for electroreduction of oxygen and H2O2 in physiological pH solutions. Electroless deposition at a short period of time (60 s), was used for strong and irreversible adsorption of 1,4,8,12‐tetraazacyclotetradecane osmium(III) chloride (Os(III)LCl2) ClO4 onto single‐walled carbon nanotubes (SWCNTs) modified GC electrode. The modified electrode shows a pair of well defined and reversible redox couple, Os(IV)/Os(III) at wide pH range (1–8). The glucose biosensor was fabricated by covering a thin film of glucose oxidase onto CNTs/Os‐complex modified electrode. The biosensor can be used successfully for selective detection of glucose based on the decreasing of cathodic peak current of oxygen. The fabricated biosensor shows high sensitivity, 826.3 nA μM−1cm−2, low detection limit, 56 nM, fast response time <3 s and wide calibration range 1.0 μM–1.0 mM. The biosensor has been successfully applied to determination of glucose in human plasma. Because of relative low applied potential, the interference from electroactive existing species was minimized, which improved the selectivity of the biosensor. The apparent Michaelis‐Menten constant of GOx on the nanocomposite, 0.91 mM, exhibits excellent bioelectrocatalytic activity of immobilized enzyme toward glucose oxidation. Excellent electrochemical reversibility, high stability, technically simple and possibility of preparation at short period of time are of great advantages of this glucose biosensor.
Electrochemical Detection of Asymmetric PCR Products by Labeling with Osmium Tetroxide
Authors: Mix Maren , Reske Thomas , Duwensee Heiko , Flechsig Gerd‐Uwe 
Published: February 2009

AbstractSingle stranded DNA‐targets from asymmetric polymerase chain reaction (PCR) of a sequence of the gram positive, spore forming bacterium Clostridium acetobutylicum were detected by square‐wave voltammetry after labeling with osmium tetroxide bipyridine and hybridization with DNA capture probes immobilized on gold electrodes. The asymmetric PCR, performed with a 10‐fold excess of the forward‐primer, was used without any further purification for hybridization with protective strands and covalent labeling with osmium tetroxide bipyridine. Square‐wave voltammetric signals of 20 nmol/L targets were significantly higher at 50 °C compared with 23 °C hybridization temperature. A fully noncomplementary protective strand yielded thoroughly modified targets unable for further hybridization. Coupling this with thermal discrimination opens new opportunities for sequence specific DNA detection.
The EOF of polymer solutions
Authors: Olivares María L. , Vera‐Candioti Luciana , Berli Claudio L. A. 
Published: February 2009

AbstractThe EOF of polymer solutions is analysed in the framework of continuum fluid mechanics and the standard electrokinetic model. Two key aspects are taken into consideration: the non‐Newtonian character of the fluid and the polymer concentration near the interface, which greatly modify the fluid viscosity in the region where electroosmosis takes place. A satisfactory mathematical model is derived for the electroosmotic mobility of solutions that present polymer depletion at the wall. The case of solutions containing polymers that adsorb onto the wall is briefly reviewed, and a preliminary approach is discussed for the limit of strong polymer adsorption. In order to illustrate the theoretical discussions, experimental data obtained from aqueous solutions of carboxymethyl cellulose in fused‐silica capillaries are presented. Relevant results are observed, which are appropriately captured by the modelling proposed. The fundamental phenomena discussed in this work are of interest in microfluidics and electrophoresis.
Bioanalytical separations using electric field gradient techniques
Authors: Meighan Michelle M. , Staton Sarah J. R. , Hayes Mark A. 
Published: February 2009

AbstractThe field of separations science will be strongly impacted by new electric‐field‐gradient‐based strategies. Many new capabilities are being developed with analytical targets ranging from particles to small molecules, and soot to living cells. Here we review the emerging area of electric field gradient techniques, dividing the large variety of techniques by the target of separation. In doing so, we have contributions using dielectrophoresis, electric field gradient focusing (including dynamic, true moving bed, and pulsed field), electrocapture and electrophoretic focusing, temperature gradient focusing, and focusing with centrifugal force. We cover the literature from the start of 2007 to June 2008, along with some introductory discussions. Even with the relatively short time frame, this young and dynamic field of inquiry produced some 100 contributions describing new and unique techniques and several new applications.
Analysis of charge heterogeneities in mAbs using imaged CE
Authors: He Xiaoping Z. , Que Amy H. , Mo Jim J. 
Published: February 2009

AbstractAn analytical method using the imaged CE (iCE) technology has been developed and validated for measuring contents of charge variants for mAb molecules. The method could generate similar information that require both conventional IEF electrophoresis and ion exchange liquid chromatography to generate as an iCE analysis would produce both the pI of the molecules and quantitative contents of charge variants. Thus, it offers unique advantages over the IEF and ion exchange methods in terms of identification, separation and quantitation of charge variants. The data presented in this study demonstrated that the iCE method is suitable not only for research purposes but also for quality control purpose of mAb clinical or commercial manufacture as the technique can be validated and possesses sufficient robustness. The developed generic iCE method has been tested for a wide range of therapeutic mAbs and proved its suitability for multiple mAb molecules. The tested mAbs are a group of molecules with a wide range of charge compositions (acidic species ranging from 10 to 70%) and a diverse range of pI of 6.9–9.6. Developing platform analytical technologies is an efficient way to meet the demand of rapid growth of therapeutic mAb candidates under clinical and preclinical development. The iCE technology is a good candidate to become a platform method as it could cover a broad range of pH gradient. The experiences learned during the developmental process would provide important and valuable information to the biotech industry for the evaluation of charge heterogeneity of mAbs in terms of release testing, characterization, stability study, process development support and comparability study.
Determination of the surface heat‐transfer coefficient in CE
Authors: Hruska Vlastimil , Evenhuis Christopher J. , Guijt Rosanne M. , Macka Miroslav , Gas Bohuslav , Marriott Philip J. , Haddad Paul R. 
Published: February 2009

AbstractA knowledge of the heat‐transfer coefficient, hs, for the external surface of the capillary or the overall heat coefficient, hOA, is of great value in predicting the mean increase in temperature of the electrolyte, ΔTMean, during electrokinetic separations. For CE, traditional indirect methods of determining hs were time‐consuming and tended to overestimate cooling efficiency; a novel method is introduced, which is based on curve‐fitting of plots of conductance versus voltage to calculate several important parameters including ΔTMean, hs, the conductance free of Joule heating effects (G0) and the voltage that causes autothermal runaway, Vlim. The new method is superior to previously published methods in that it can be performed more quickly and that it corrects for systematic errors in the measurement of electric current for voltages <5 kV. These errors tended to exaggerate the cooling efficiency of commercial instruments so that the calculated increases in electrolyte temperature were smaller than their actual values. Axially averaged values for hs were determined for three different commercial CE instruments ranging from 164 W m−2 K−1 for a passively cooled instrument in a drafty environment to 460 W m−2 K−1 for a liquid‐cooled instrument.
Two variable semi‐empirical and artificial neural‐network‐based modeling of peptide mobilities in CZE: The effect of temperature and organic modifier concentration
Authors: Mittermayr Stefan , Chovan Tibor , Guttman András 
Published: February 2009

AbstractThis work was focused on investigating the effects of two separation influencing parameters in CZE, namely temperature and organic additive concentration upon the electrophoretic migration properties of model tripeptides. Two variable semi‐empirical (TVSE) models and back‐propagation artificial neural networks (ANN) were applied to predict the electrophoretic mobilities of the tripeptides with non‐polar, polar, positively charged, negatively charged and aromatic R group characteristics. Previously published work on the subject did not account for the effect of temperature and buffer organic modifier concentration on peptide mobility, in spite of the fact that both were considered to be influential factors in peptide analysis. In this work, a substantial data set was generated consisting of actual electrophoretic mobilities of the model tripeptides in 30 mM phosphate buffer at pH 7.5, at 20, 25, 30, 35 and 40°C and at four different organic additive containing running buffers (0, 5, 10 and 15% MeOH) applying two electric field strengths (12 and 16 kV) to assess our mobility predicting models. Based on the Arrhenius plots of natural logarithm of mobility versus reciprocal absolute temperature of the various experimental setups, the corresponding activation energy values were derived and evaluated. Calculated mobilities by TVSE and back‐propagation ANN models were compared with each other and to the experimental data, respectively. Neural network approaches were able to model the complex impact of both temperature and organic additive concentrations and resulted in considerably higher predictive power over the TVSE models, justifying that the effect of these two factors should not be neglected.
Requirement of the Saccharomyces cerevisiae APN1 gene for the repair of mitochondrial DNA alkylation damage
Authors: Acevedo‐Torres Karina , Fonseca‐Williams Sharon , Ayala‐Torres Sylvette , Torres‐Ramos Carlos A. 
Published: February 2009

AbstractThe Saccharomyces cerevisiae APN1 gene that participates in base excision repair has been localized both in the nucleus and the mitochondria. APN1 deficient cells (apn1Δ) show increased mutation frequencies in mitochondrial DNA (mtDNA) suggesting that APN1 is also important for mtDNA stability. To understand APN1‐dependent mtDNA repair processes we studied the formation and repair of mtDNA lesions in cells exposed to methyl methanesulfonate (MMS). We show that MMS induces mtDNA damage in a dose‐dependent fashion and that deletion of the APN1 gene enhances the susceptibility of mtDNA to MMS. Repair kinetic experiments demonstrate that in wild‐type cells (WT) it takes 4 hr to repair the damage induced by 0.1% MMS, whereas in the apn1Δ strain there is a lag in mtDNA repair that results in significant differences in the repair capacity between the two yeast strains. Analysis of lesions in nuclear DNA (nDNA) after treatment with 0.1% MMS shows a significant difference in the amount of nDNA lesions between WT and apn1Δ cells. Interestingly, comparisons between nDNA and mtDNA damage show that nDNA is more sensitive to the effects of MMS treatment. However, both strains are able to repair the nDNA lesions, contrary to mtDNA repair, which is compromised in the apn1Δ mutant strain. Therefore, although nDNA is more sensitive than mtDNA to the effects of MMS, deletion of APN1 has a stronger phenotype in mtDNA repair than in nDNA. These results highlight the prominent role of APN1 in the repair of environmentally induced mtDNA damage. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.
Areca nut‐induced micronuclei and cytokinesis failure in Chinese hamster ovary cells is related to reactive oxygen species production and actin filament deregulation
Authors: Lin Chiu‐Chun , Chang Mei‐Chi , Chang Hsiao‐Hua , Wang Tong‐Mei , Tseng Wan‐Yu , Tai Tseng‐Fang , Yeh Hung‐Wei , Yang Ting‐Ting , Hahn Liang‐Jiunn , Jeng Jiiang‐Huei 
Published: February 2009

AbstractEpidemiological studies have shown a strong association between environmental exposure to betel quid (BQ) and oral cancer. Areca nut (AN), an ingredient of BQ, contains genotoxic and mutagenic compounds. In this study, we found that AN extract (ANE) inhibited the growth of Chinese hamster ovary cells (CHO‐K1) in a dose‐ and time‐dependent manner. Intracellular reactive oxygen species (ROS) levels and micronuclei (MN) frequency were significantly increased following ANE treatment in CHO‐K1 cells. Addition of catalase markedly inhibited ANE‐induced MN formation, indicating that ANE‐induced genotoxicity was correlated with intracellular H2O2. Incubation of CHO‐K1 cells with ANE (400–800 μg/ml) for 24 hr caused G2/M arrest, and prolonged exposure to ANE (800 μg/ml) significantly induced cell death. Surprisingly, ANE itself caused cytokinesis failure and subsequent increase in binucleated cell formation. Coexposure to catalase (2,000 U/ml) and ANE (800 μg/ml) reduced the generation of binucleated cells, indicating that ANE‐induced cytokinesis failure was associated with oxidative stress. Following prolonged exposure to ANE, an accumulation of hyperploid/aneuploid cells concomitant with bi‐, micro‐ or multinucleated cells was found. In summary, our results demonstrate that ANE exposure to CHO‐K1 cells caused increased MN frequency, G2/M arrest, cytokinesis failure, and an accumulation of hyperploid/aneuploid cells. These events are associated with an increase in intracellular H2O2 level and actin filament disorganization. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.
Apoptosis induction in human lung adenocarcinoma cells by oil‐soluble allyl sulfides: Triggers, pathways, and modulators
Authors: Wu Xin‐Jiang , Hu Ying , Lamy Evelyn , Mersch‐Sundermann Volker 
Published: February 2009

AbstractDAS (diallyl sulfide), DADS (diallyl disulfide), and DATS (diallyl trisulfide) are major oil‐soluble allyl sulfides (OAS) that represent major garlic constituents. The anticarcinogenic and antimutagenic effects of these substances have been extensively studied during the last decades. Previous reports suggest that induction of apoptosis by OASs might contribute to their chemopreventive effects. In this study, we report that OASs DADS and DATS induce significant apoptosis in human lung adenocarcinoma A549 cells, whereas DAS does not. Differential modulation of reactive oxygen intermediates (ROI) and mitochondria membrane potential (MMP) may account for the apoptotic effects of DADS and DATS. The underlying molecular mechanisms of apoptosis induction by both compounds include activation of C‐Jun N‐terminal kinase (JNK), up‐regulation of p53, and down‐regulation of bcl‐2 expression. In our test series, up‐regulation of extracellular signal‐regulated protein kinase (ERK) was dispensable for apoptosis induction; DAS, DADS, or DATS did not modify expression of MAPK p38, bax, and bcl‐xL. Further investigation revealed that the specific JNK inhibitor SP600125 and the antioxidant NAC blocked DADS and DATS‐induced apoptosis, whereas ERK inhibitors did not. Additionally, our data provide the first evidence that Fas‐mediated cell death pathway is partly involved in DADS but not DATS‐mediated cell death. Taken together, our work has elucidated the triggers, important modulators, and signal transduction pathways in DADS and DATS‐mediated apoptosis. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.
Antioxidant and pro‐oxidant capacities of ITCs
Authors: Valgimigli Luca , Iori Renato 
Published: February 2009

AbstractIsothiocyanates (ITCs) are breakdown products of glucosinolates contained in cruciciferous vegetables. This heterogeneous family of molecules has the NCS group as its common structural feature and possesses important cytoprotective properties. Their biological interactions are strongly related to modulation of cellular redox status, and a number of studies have documented their indirect antioxidant properties, particularly related to induction of phase‐2 enzymes. On the other hand, some direct antioxidant behavior has also been observed for a limited number of ITCs. Paradoxically relevant pro‐oxidant properties have also been documented, possibly related to the simultaneous induction of phase‐1 enzymes. In this review, we will summarize and discuss the prevailing mechanisms for the antioxidant and pro‐oxidant activity of ITCs, both in vivo and in vitro. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.
Analysis of cellular response to isocyanate using N‐succinimidyl N‐methylcarbamate exposure in cultured mammalian cells
Authors: Mishra Pradyumna Kumar , Gorantla Venkata Raghuram , Akhtar Nabila , Tamrakar Priyanka , Jain Subodh Kumar , Maudar Kewal Krishan 
Published: February 2009

AbstractIsocyanates (RNCO), one of the highly reactive industrial intermediates, possess the capability to modulate the bio‐molecules by forming toxic metabolites and adducts which may cause adverse health effects. Some of their toxic degradations have previously been unknown and overlooked; of which, molecular repercussions underlying their genetic hazards upon occupational/accidental exposures still remain as an intricate issue and are hitherto unknown. To assess the genotoxic potential of methyl isocyanate in cultured mammalian cells after in vitro exposure, we performed a study in three different normal cell lines MM55.K (mouse kidney epithelial), B/CMBA.Ov (mouse ovarian epithelial), and NIH/3T3 (primary mouse embryonic fibroblast). Cellular DNA damage response was studied for qualitative phosphorylation states of ATM, γH2AX proteins and quantitative state of p53 phosphorylation; DNA cell cycle analysis and measure of cellular apoptotic index before and after treatment were also investigated. Our results demonstrate that methyl isocyanate by negatively regulating the DNA damage response pathway, might promote cell cycle arrest, and apoptosis in cultured mammalian cells suggestive of causing genetic alterations. We anticipate that these data along with other studies reported in the literature would help to design better approaches in risk assessment of occupational and accidental exposure to isocyanates. We also predict that increasing knowledge on DNA damage‐triggered signaling leading to cell death could provide new strategies for investigating the effects of DNA repair disorders and decreased repair capacity on the toxicity and carcinogenic properties of environmental toxins. Environ. Mol. Mutagen., 2009. © 2009 Wiley‐Liss, Inc.
Human impact on fixed sand dunes revealed by morphometric analysis
Authors: Kiss Tímea , Sipos György , Kovács Ferenc 
Published: February 2009

AbstractThe Nyírség is the second largest alluvial fan in Hungary covered by fixed sand dunes. The primary aim of the paper is to describe the morphology of dunes in the region and classify them based on their morphometric characteristics. The other major aim is to select those dunes which were exposed to significant anthropogenic impact, and to determine the spatial and temporal differences in the intensity of human activity. The following dune types were separated: valley‐marginal, transitional valley‐marginal, transitional parabolic, filled, partially and unfilled parabolic dunes. After defining different dune types and their parameters, certain dunes were selected based on exposure to significant anthropogenic impact. Definite connection was demonstrated between the intensity of human environmental impact and the rate of erosion on fixed sand dunes. The erosion of sand dunes was most intensive in Medieval times, most likely due to concentration of agricultural land use. Copyright © 2009 John Wiley & Sons, Ltd.