bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumer perception of salesperson influence strategies: an examination of the influence of consumer goals
Authors: Mallalieu Lynnea
Published: July 2006

Consumers regularly interact with retail salespeople in order to make purchases across a wide range of products and services. Retail sales encounters occur on a daily basis yet we know little about these complex interactions, especially from the consumer's perspective in terms of his or her perceptions with regard to these types of persuasive attempts. Understanding consumer perceptions is an important precursor to understanding consumer behavior during retail sales encounters. In three experiments subjects' perceptions of specific influence strategies were measured with regard to the degree of sales‐orientation of each strategy. Support was found for hypotheses that proposed that certain influence strategies would be perceived as significantly more sales‐oriented than others and that the interaction of consumer goals with salesperson influence would affect how influence strategies are perceived. Willingness to interact with and purchase from a salesperson using specific influence strategies was also examined in order to shed light on how the use of specific influence strategies is likely to affect consumers' intentions.

Copyright © 2006 John Wiley & Sons, Ltd.
Exploring consumers' health meaning categories: towards a health consumption meaning model
Authors: Luomala Harri T , Paasovaara Rami , Lehtola Katariina
Published: July 2006

Health marketplace offers a lucrative business for many companies. However, there is a gap in consumer research in understanding what health as a target of consumption really means to consumers. The subtleties and multiplicity of meanings rural and urban (both younger and older) consumers attach to health in their everyday lives are empirically explored in this article. Findings of a focus group interview‐based interpretive analysis are reported. It was found that meanings consumers associate with health are profound and multi‐faceted (identification of several health‐meaning categories) with some evidence for age‐ and area‐of‐ residency‐related health‐meaning differences. The article is concluded by advancing theory‐building in consumer research in the form of developing a tentative framework model that can be used to analyze health consumption meanings.

Copyright © 2006 John Wiley & Sons, Ltd.
Assaying Sialyltransferase Activity with Surface Plasmon Resonance
Authors: Plath Christian , Weimar Thomas , Peters Hannelore , Peters Thomas
Published: July 2006

Here, we describe an activity assay for sialyltransferases based on surface plasmon resonance (SPR). Different natural and synthetic oligosaccharides serving as acceptor substrates for the sialyltransferase ST3Gal‐III (EC 2.4.99.6) were immobilized or synthesized on SPR chips. The chip was then exposed to different concentrations of a reaction mixture of ST3Gal‐III and CMP‐Neu5Ac either by injection or by external application of the reaction mixture to the chip surface. The binding of two lectins, one that specifically recognizes the unmodified acceptor, the other the sialylated oligosaccharide, was utilized to determine the extent of enzymatic turnover. In order to obtain enzymatic activities, the SPR data were correlated to data obtained from a classical radio assay. After regeneration, that is, cleavage of the sialic acid residues by using a sialidase, the chip is available for new experiments. The technique allows the rapid determination of sialyltransferase activity with only nanomolar quantities of acceptor substrates and should be of particular value in cases in which a large variety of samples, including cell lysates, have to be screened for their enzymatic activities.
Effects of Surface Charge on Denaturation of Bovine Carbonic Anhydrase
Authors: Gitlin Irina , Gudiksen Katherine L. , Whitesides George M.
Published: July 2006

This work compares the denaturation of two proteins—bovine carbonic anhydrase II (BCA) and its derivative with all lysine groups acetylated (BCA‐Ac18)—by urea, guanidinium chloride (GuHCl), heat, and sodium dodecyl sulfate (SDS). It demonstrates that increasing the net negative charge of the protein by acetylation of lysines reduces its stability to urea, GuHCl, and heat, but increases its kinetic stability (its thermodynamic stability cannot be measured) towards denaturation by SDS. Increasing the ionic strength of the buffer improves the stability of BCA‐Ac18 to urea and heat, but still leaves it less stable than unacetylated BCA to those denaturants. In urea, the large change in electrostatic interactions not only modifies the free energy of denaturation, but also introduces a stable intermediate into the unfolding pathway. This work shows that modifications of charges on the surfaces of proteins can have a large effect—positive or negative, depending on the denaturant—on the stability of the proteins despite the exposure of these charges to high dielectric solvent and buffer ions.
Pyrene as Chromophore and Electrophore: Encapsulation in a Rigid Polyphenylene Shell
Authors: Bernhardt Stefan , Kastler Marcel , Enkelmann Volker , Baumgarten Martin , Müllen Klaus
Published: July 2006

Starting from the fourfold ethynyl‐substituted chromophore 1,3,6,8‐tetraethynylpyrene as core, a series of polyphenylene dendrimers was prepared in high yield by combining divergent and convergent growth methods. The fluorescence quantum yields (Qf>0.92) of the encapsulated pyrene chromophore were independent of the size of the polyphenylene shell. Fluorescence quenching studies and temperature‐dependent fluorescence spectroscopy were performed to investigate the site isolation of the core. They indicate that a second‐generation dendrimer layer is needed to efficiently shield the encapsulated pyrene and prevent aggregate formation. Alkali‐metal reduction of the encapsulated pyrene core was carried out to afford the corresponding pyrene radical anions, for which hampered electron transfer to the core was observed with increasing dendrimer generation, which is further proof of the site isolation due to the polyphenylene shell. To improve film formation and solubility of the material, solubilizing alkyl chains were introduced on the periphery of the spherical particles. Furthermore, highly transparent films obtained by a simple drop‐casting method showed blue emission mainly from the unaggregated species. The materials presented herein combine high quantum efficiency, good solubility, and improved film‐forming properties, which make them possible candidates for several applications in electronic devices.
Molecular characterization of Ciona sperm outer arm dynein reveals multiple components related to outer arm docking complex protein 2
Authors: Hozumi Akiko , Satouh Yuhkoh , Makino Yumiko , Toda Toshifusa , Ide Hiroyuki , Ogawa Kazuo , King Stephen M. , Inaba Kazuo
Published: July 2006

Using proteomic and immunochemical techniques, we have identified the light and intermediate chains (IC) of outer arm dynein from sperm axonemes of the ascidian Ciona intestinalis. Ciona outer arm dynein contains six light chains (LC) including a leucine‐rich repeat protein, Tctex1‐ and Tctex2‐related proteins, a protein similar to Drosophila roadblock and two components related to Chlamydomonas LC8. No LC with thioredoxin domains is included in Ciona outer arm dynein. Among the five ICs in Ciona, three are orthologs of those in sea urchin dynein: two are WD‐repeat proteins and the third one, unique to metazoan sperm flagella, contains both thioredoxin and nucleoside diphosphate kinase modules. The remaining two Ciona ICs have extensive coiled coil structure and show sequence similarity to outer arm dynein docking complex protein 2 (DC2) that was first identified in Chlamydomonas flagella. We recently identified a third DC2‐like protein with coiled coil structure, Ci‐Axp66.0 that is also associated in substoichiometric amounts with Ciona outer arm dynein. In addition, Oda5p, a component of an additional complex required for assembly of outer arm dynein in Chlamydomonas flagella, also groups with this family of DC2‐like proteins. Thus, the assembly of outer arm dynein onto doublet microtubules involves multiple coiled‐coil proteins related to DC2. Cell Motil. Cytoskeleton 2006. © 2006 Wiley‐Liss, Inc.
Consensus report of the International Society of Gastrointestinal Oncology on therapeutic progress in advanced pancreatic cancer
Authors: Hochster Howard S. , Haller Daniel G. , de Gramont Aimery , Berlin Jordan D. , Philip Philip A. , Moore Malcolm J. , Ajani Jaffer A.
Published: July 2006

Since 1997, when gemcitabine showed superior clinical benefit to single‐agent5‐fluorouracil, it has remained the standard of care for the treatment of advanced pancreatic cancer. Numerous new agents, both cytotoxic and targeted, have been tested against this standard. Some trials showed improved response rates or progression free survival, but there was no clear improvement in survival. For the current report, those trial results were reviewed in depth for methodology, endpoints, and study characteristics. More recent studies have shown progress. Studies with combinations of gemcitabine and capecitabine and with the epidermal growth factor receptor antagoinist, erlotinib, have demonstrated survival benefits. Currently, studies of combinations with oxaliplatin, bevacizumab, and cetuximab are ongoing. Other targeted therapies also are considered for future clinical trials. Based on a comprehensive review of past trials, a consensus on endpoints in the treatment of pancreatic cancer and an approach to new trials is presented. Cancer 2006. © 2006 American Cancer Society.
A prognostic model for advanced stage nonsmall cell lung cancer
Authors: Mandrekar Sumithra J. , Schild Steven E. , Hillman Shauna L. , Allen Katie L. , Marks Randolph S. , Mailliard James A. , Krook James E. , Maksymiuk Andrew W. , Chansky Kari , Kelly Karen , Adjei Alex A. , Jett James R.
Published: July 2006

BACKGROUND.

A pooled analysis was performed to examine the impact of pretreatment factors on overall survival (OS) and time to progression (TTP) in patients with advanced‐stage nonsmall cell lung cancer (NSCLC) and to construct a prediction equation for OS using pretreatment factors.

METHODS.

A pooled data set of 1053 patients from 9 North Central Cancer Treatment Group trials was used. Age, gender, Eastern Cooperative Oncology Group performance status (PS), tumor stage (Stage IIIB vs. Stage IV), body mass index (BMI), creatinine level, hemoglobin (Hgb) level, white blood cell (WBC) count, and platelet count were evaluated for their prognostic significance in both univariate and multivariate analyses by using a Cox proportional‐hazards model.

RESULTS.

Patients who had high WBC counts, low Hgb levels, PS >0, BMI <18.5 kg/m2, and TNM Stage IV disease had significantly worse TTP and OS. Patients who had Stage IV disease with a high WBC count had a particularly poor prognosis. An equation to predict the OS of patients with Stage IV NSCLC based on pretreatment PS, BMI, Hgb level, and WBC count was constructed.

CONCLUSIONS.

In addition to the widely accepted prognostic factors of PS, BMI, and disease stage, both of the readily available laboratory parameters of Hgb level and WBC count were found to be significant prognostic factors for OS and TTP in patients with advanced‐stage NSCLC. The authors' prediction equation can be used to evaluate the benefit of a treatment in Phase II trials by comparing the observed survival of a cohort with its expected survival by using the patients' own prognostic factors in place of comparisons with historic data that may have substantially different baseline patient characteristics. Cancer 2006. © 2006 American Cancer Society.
Homocysteine and vitamin B12 concentrations and mortality rates in type 2 diabetes
Authors: Looker Helen C. , Fagot‐Campagna Anne , Gunter Elaine W. , Pfeiffer Christine M. , Sievers Maurice L. , Bennett Peter H. , Nelson Robert G. , Hanson Robert L. , Knowler William C.
Published: July 2006

Objective

To assess the role of homocysteine as a risk factor for mortality in diabetic subjects.

Methods

Homocysteine, vitamin B12, and folate concentrations were measured in stored sera of 396 diabetic Pima Indians aged ≥40 years when examined between 1982 and 1985. Vital status was assessed through 2001.

Results and Conclusions

Over a median follow‐up of 15.7 years, there were 221 deaths—76 were due to cardiovascular disease (CVD), 36 to diabetes/nephropathy and 34 to infections. Homocysteine was positively associated with mortality from all causes (hazard rate ratio (HRR) for highest versus lowest tertile of homocysteine = 1.70, 95% confidence interval (CI) 1.18–2.46), from diabetes/nephropathy (HRR = 2.39, 95% CI 0.94–6.11) and from infectious diseases (HRR = 3.39, 95% CI 1.19–9.70), but not from CVD (HRR = 1.16, 95% CI 0.62–2.17) after adjustment for age, sex and diabetes duration. Homocysteine correlated with serum creatinine (r = 0.50), and the relationships with mortality rates were not significant after adjustment for creatinine. Vitamin B12 was positively associated with all‐cause mortality (HRR for 100 pg/mL difference adjusted for age, sex and diabetes duration = 1.15, 95% CI 1.08–1.22) and death from diabetes/nephropathy (HRR = 1.27, 95% CI 1.10–1.46). The association between homocysteine and mortality in type 2 diabetes is not causal, but is confounded by renal disease in Pima Indians. Copyright © 2006 John Wiley & Sons, Ltd.
Nestin‐Cre transgenic mouse line Nes‐Cre1 mediates highly efficient Cre/loxP mediated recombination in the nervous system, kidney, and somite‐derived tissues
Authors: Dubois Nicole C. , Hofmann Denise , Kaloulis Kostas , Bishop J.M. , Trumpp Andreas
Published: July 2006

Here we describe the generation of the Nes‐Cre1 transgenic mouse line in which Cre recombinase expression is controlled by the rat nestin promoter and intron 2 enhancer. This line has previously been used for conditional loss‐of‐function studies of various genes in the central nervous system and first branchial arch ectoderm. Here we report the detailed temporal and spatial recombination pattern of Nes‐Cre1 using three different reporters of Cre‐mediated recombination, ROSA26R (R26R), Z/AP, and Z/EG. Cre/loxP recombination was detected in embryos as early as the head‐fold stage. By embryonic day (E)15.5 recombination occurred in virtually all cells of the nervous system and unexpectedly also in somite‐derived tissues and kidneys. Tissues with little or no recombination included heart, liver, thymus, and lung. This study suggests that Nes‐Cre1‐mediated recombination occurs in progenitor cell types present in the neuroectoderm, the developing mesonephros, and the somites. genesis 44:355–360, 2006. © 2006 Wiley‐Liss, Inc.
Power, optimism, and risk‐taking
Authors: Anderson Cameron , Galinsky Adam D.
Published: July 2006

Five studies investigated the hypotheses that the sense of power increases optimism in perceiving risks and leads to more risky behavior. In Studies 1 and 2, individuals with a higher generalized sense of power and those primed with a high‐power mind‐set were more optimistic in their perceptions of risk. Study 3 primed the concept of power nonconsciously and found that both power and gain/loss frame had independent effects on risk preferences. In Study 4, those primed with a high‐power mind‐set were more likely to act in a risk‐seeking fashion (i.e., engage in unprotected sex). In Study 5, individuals with a higher sense of power in a face‐to‐face negotiation took more risks by divulging their interests. The effects of power on risk‐taking were mediated by optimistic risk perceptions and not by self‐efficacy beliefs. Further, these effects were attenuated when the high‐power individual felt a sense of responsibility. Copyright © 2006 John Wiley & Sons, Ltd.
On the varieties of asymmetrical dependency: feelings, motives, behavior, and accuracy in a dyadic interaction
Authors: Hall Judith A. , Murphy Nora A. , Carney Dana R.
Published: July 2006

Asymmetrical outcome dependency (AOD) has been theorized to produce feelings of powerlessness and anxiety, as well as a heightened motive to be interpersonally accurate. Thus far, the research on AOD has been conducted mainly among participants who were anticipating an outcome‐dependent interaction. Using both self‐report and behavioral measures, the present research investigated the feelings, motives, behavior, and interpersonal accuracy of participants engaged in dyadic task accomplishment under AOD, individual evaluation by the partner (EDP), individual evaluation by the experimenter (EDE), or no dependency. AOD participants showed relatively high levels of felt dominance, less attention to the partner, less happy affect, and less motivational investment than one or more of the other groups. EDP participants appeared to be most interested in being accurate and in making a good impression. No group differences were observed for interpersonal accuracy or anxiety. Copyright © 2006 John Wiley & Sons, Ltd.
The effects of prejudice level and social influence strategy on powerful people's responding to racial out‐group members
Authors: Vescio Theresa K. , Gervais Sarah J. , Heidenreich Swen , Snyder Mark
Published: July 2006

This research tested the hypothesis that the responding of high, but not low, prejudice White Americans would vary as a function of manipulations of powerful people's attention to subordinate strengths that facilitate goal strivings versus weaknesses that block goals. To examine this possibility, White participants were assigned to leader roles and an interaction with a low power Black ‘employee’ was staged. Consistent with predictions, findings revealed that high prejudice White participants who were attentive to subordinate strengths and goal strivings versus subordinate weaknesses and blocked goals, evaluated and treated a Black employee more positively. The responding of low prejudice participants did not, however, vary as a function of attention to strengths and goal facilitation versus weaknesses and blocked goals. Findings suggest that stereotypes of the groups to which low power people belong influence powerful people's judgment and behavior when stereotypes are endorsed by powerful people and match powerful people's goals. Copyright © 2006 John Wiley & Sons, Ltd.
Striving for personal power as a basis for social power dynamics
Authors: van Dijke Marius , Poppe Matthijs
Published: July 2006

It has often been proposed that people are intrinsically motivated to gain or increase power over others. We argue that theoretical underpinnings of such a claim are lacking. Moreover, empirical support for this claim is more convincingly explained by strivings to increase one's sense of agency (personal power) by decreasing dependence on others, rather than by strivings to increase power over others (social power). In two experiments, we directly tested the explanatory value of the personal power concept. In Experiment 1, participants performed a decision‐making task, together with a (simulated) other person. The power of the two persons over each other was manipulated orthogonally by varying the control they had over each other's decisions. As expected, the participants mostly increased their personal power, by decreasing their dependence on the other person's power. They did not increase their social power but even decreased it when they were very superior themselves. Comparable findings were obtained in Experiment 2, in which participants interacted with another person whose decisions conflicted with those made by the participant. Copyright © 2006 John Wiley & Sons, Ltd.
Holding onto power: effects of powerholders' positional instability and expectancies on interactions with subordinates
Authors: Georgesen John , Harris Monica J.
Published: July 2006

This study explores the effects of power, positional threat, and expectancies on interactions between powerholders and subordinates. Two hundred and forty‐two participants were randomly assigned to power role (boss or employee). Bosses were further randomly assigned to levels of positional threat (power role secure or insecure) and expectancy regarding subordinates' problem‐solving ability (negative or positive). Evidence for a self‐fulfilling prophecy was obtained, such that dyads where bosses held negative expectancies of their subordinates rated the subordinate and experience most negatively and awarded less potential prize money to the subordinates. Expectancy interacted with positional threat in a consistent manner such that the most negative effects were obtained for dyads where bosses were both positionally threatened and held negative expectancies of subordinates. Implications for theories of power are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Electrochemical Sandwich Immunoassay for Vitellogenin by Sequential Injection Analysis Using Antibody Immobilized Magnetic Microbeads
Authors: Hirakawa Koji , Katayama Masaaki , Soh Nobuaki , Nakano Koji , Ohura Hiroki , Yamasaki Sumio , Imato Toshihiko
Published: July 2006

A rapid and sensitive sandwich immunoassay based on a sequential injection analysis (SIA) for the determination of carp vitellogenin (Vg) is described. The SIA system was constructed from a syringe pump, a multiposition valve, a flow‐through type immunoreaction cell equipped with a magnet and an amperometric detector. Magnetic microbeads immobilized with an anti‐Vg monoclonal antibody (primary antibody) were used as a solid support. The primary antibody was immobilized on magnetic microbeads by coupling the primary antibody with a polylactic acid‐layer, which was coated on the surface of the magnetic beads, after activated with N‐hydroxysuccinimide. The introduction, trapping and flushing out of the magnetic microbeads in the immunoreaction cell were controlled by the magnet and the flow of the carrier solution. After the primary antibody‐immobilized magnetic beads were introduced and trapped in the immunoreaction cell, a Vg sample solution, an alkaline phosphatase (AP)‐labeled anti‐Vg polyclonal antibody (secondary antibody) solution and a p‐aminophenyl phosphate (PAPP) solution were sequentially introduced into the immunoreaction cell based on an SIA programmed sequence. Vg was determined by the electrochemical detection of p‐aminophenol (PAP), an enzymatic product of PAPP via the action by AP labeled on the secondary antibody. A solution containing PAP, which was generated in the immunoreaction cell and transiently held in a holding coil, was transported to the amperometric detector and the oxidation current of PAP on a working electrode applied at +0.20 V was measured. A sigmoidal calibration curve was obtained in the concentration range from 1 ppb to 500 ppb in a plot of oxidation current against the logarithm of the Vg concentration. The lower detection limit of the immunoassay was about 2–3 ppb. The time required for an analysis was ca. 15 min/sample.
General Kinetic Model for Amperometric Sensors Based on Prussian Blue Mediator and Its Analogs: Application to Cysteine Detection
Authors: Chen Lin‐Chi , Tseng Kuei‐Sheng , Ho Kuo‐Chuan
Published: July 2006

Prussian blue (PB) and its analogs, such as indium hexacyanoferrate (InHCF), can serve as artificial oxidases and mediate electron transfer from electrodes to analytes rapidly. Hence they are playing a growing role in the biosensor field. To gain further insight into the PB‐based amperometric sensors, a general kinetic model for the prediction of sensing current has been developed in this work. The model takes both effects of analyte diffusion and electrocatalytic reaction into consideration and defines a dimensionless system constant, θ°, in order to compare the surface catalytic rate with the analyte diffusion rate. Consequently, the mathematical expression of sensing current, I, is derived as follows:
Amperometric Detection of Cysteine at an In3+ Stabilized Indium Hexacyanoferrate Modified Electrode
Authors: Tseng Kuei‐Sheng , Chen Lin‐Chi , Ho Kuo‐Chuan
Published: July 2006

This research focuses on the stabilization of indium hexacyanoferrate (InHCF) modified electrode in aqueous solution and the amperometric detection of cysteine (Cys). It was found that the stability of the InHCF modified electrode in the aqueous solution could be improved upon adding In3+ in the solution. EQCM experiments verified that such an In3+ addition greatly inhibited an oxidized InHCF thin film's dissociation and thus considerably stabilizes the InHCF modified electrode. The amperometric detection was performed by the application of a static potential at 1.2 V, with the sampling time at 30 s. The sampled current was linearly dependent on [Cys] when [Cys] was ranged from 100 μM to 1 mM. The sampled current approached a plateau gradually with the increase in the concentration of cysteine. The trend of calibration curve at the InHCF modified electrode generally follows the Michaelis–Menten type kinetics, and Km and vmax were calculated to be 3.86 mM and 30.2 μA, respectively, from the Lineweaver–Burke plot. In addition, the amperometric detection was reversible and reproducible with relative standard deviations of 2.79%.
Nitrate‐Selective Solid Contact Electrodes with Poly(3‐octylthiophene) and Poly(aniline) as Ion‐to‐Electron Transducers Buffered with Electron‐Ion‐Exchanging Resin
Authors: Khripoun Galina A. , Volkova Elina A. , Liseenkov Artiom V. , Mikhelson Konstantin N.
Published: July 2006

The study of nitrate selective solid contact electrodes containing poly(3‐octyl)thiophene and poly(aniline) demonstrated the advantage of buffering the transducing layer with electron‐ion‐exchanging resin. The buffering, in particular in the case of poly(aniline) doped with nitrate anions ensured significant improvement of the long‐term stability and piece‐to‐piece reproducibility of the electrode potentials. It is shown that the redox species causes potential drift after a long time delay, probably because of slow diffusion in the membrane bulk.
Amperometric Sensor for Heparin: Sensing Mechanism and Application in Human Blood Plasma Analysis
Authors: Langmaier Jan , Olšák Jiří , Samcová Eva , Samec Zdeněk , Trojánek Antonín
Published: July 2006

Voltammetric measurements of heparin at a rotating glassy carbon (GC) electrode coated with a polyvinylchloride membrane are reported. A spin‐coating technique is used to prepare thin membranes (20–40 μm) with a composition of 25% (w/w) PVC, 1,1′‐dimethylferrocene as a reference electron donor for the GC|membrane interface, nitrophenyl octyl ether (o‐NPOE) or bis(2‐ethylhexyl) sebacate (DOS) as a plasticizer, and hexadecyltrimethylammonium tetrakis(4‐chlorophenyl) borate (HTMATPBCl) or tridodecylmethylammonium tetrakis(4‐chlorophenyl) borate (TDMATPBCl) as a background electrolyte. It is shown that the electrodes coated with either the HTMA+/o‐NPOE (DOS) or TDMA+/o‐NPOE (DOS) membrane provide a comparable amperometric response towards heparin (1–10 U mL−1) in the aqueous solution of 0.1 M LiCl. However, only the membranes formulated with TDMATPBCl can be used for an amperometric assay of heparin in human blood plasma with a detection limit of 0.2 U mL−1. Effects of membrane composition, heparin concentration, rotation speed and sweep rate on the voltammetric behavior of heparin provide some insight into the sensing mechanism. Theoretical analysis of the amperometric response is outlined, and the numeric simulation of the voltammetric behavior is presented.
Ionic Liquids Plasticize and Bring Ion‐Sensing Ability to Polymer Membranes of Selective Electrodes
Authors: Shvedene Natalia V. , Chernyshov Denis V. , Khrenova Maria G. , Formanovsky Andrey A. , Baulin Vladimir E. , Pletnev Igor V.
Published: July 2006

Due to the polymer plasticizing ability and ionic nature of ionic liquids (bistrifluoromethanesulfonimidate salts of 1‐butyl‐2,3‐dimethylimidazolium and dodecylethyldiphenylphosphonium, BDMIm Tf2N and DEDPP Tf2N, respectively), they were found to be excellent compounds for preparing ion‐selective membrane electrodes. Membrane polymers studied were poly(methyl methacrylate) and poly(vinyl chloride). The electrodes demonstrated good and extremely stable response to both cations and anions (including surfactants) and were successfully applied to the analysis of detergents.
Bismuth Film Electrode for the Cathodic Electrochemical Determination of Thiamethoxam
Authors: Guzsvány Valéria , Kádár Mihály , Gaál Ferenc , Bjelica Luka , Tóth Klára
Published: July 2006

A cathodic electrochemical application of bismuth film modified glassy carbon electrode was investigated with the objective of determining thiamethoxam insecticide. The conditions of bismuth film deposition (electrode pretreatment procedure, composition of the plating solution, plating potential and film stability) were optimized using electrochemical and microscopic techniques. It was found that the bismuth film generation on glassy carbon substrate in a plating solution of 0.02 M Bi(NO3)3, 1 M HCl and 0.5 M KBr, at −0.25 V (vs. Ag/AgCl/3 M KCl) for 60 s and subsequent electrochemical conditioning yielded a modified electrode suitable for analytical purposes. Thiamethoxam was determined by differential pulse voltammetry in Britton–Robinson buffer of pH 8.0 in the concentration range of 1.26–45.0 μg/cm3. The reproducibility of the analytical signal was characterized by a relative standard deviation smaller than 1.5%, and the calculated values of detection and quantitation limits were 0.38 μg/cm3 and 1.26 μg/cm3, respectively. The applicability of the modified electrode was tested on real, agriculturally‐incurred potato and maize samples.
Microcavity Based Solid‐Contact Ion‐Selective Microelectrodes
Authors: Sundfors Fredrik , Bereczki Róbert , Bobacka Johan , Tóth Klára , Ivaska Ari , Gyurcsányi Róbert E.
Published: July 2006

A novel design and fabrication procedure is proposed for the preparation of robust ionophore based ion‐selective microelectrodes. The essential component of the new design is a microcavity that is formed after recessing a voltammetric inlaid disk type gold microelectrode by chemical etching of the gold microwire. The microcavity of ca. 50 pL volume and 25 μm diameter accommodates the inherently conducting polymeric inner contact and the ion‐selective liquid membrane, which are thereby mechanically protected from the sample environment. As inner contacts poly(3,4‐ethylenedioxythiophene) (PEDOT) films doped with poly(4‐styrenesulfonate) (PSS) and tetrakis[3,5‐bis‐(trifluoromethyl)phenyl]borate (TFPB) electropolymerized from aqueous and organic solvents, respectively, were used. Potassium‐ and calcium‐selective microelectrodes fabricated according to the new procedure exhibited potentiometric characteristics similar to the conventional electrodes. The formation of an aqueous layer below the ion‐selective membrane could be avoided by using the proposed electrode construction.
Trace‐Level Determination of Cs+ Using Membrane‐Based Ion‐Selective Electrodes
Authors: Radu Aleksandar , Peper Shane , Gonczy Chad , Runde Wolfgang , Diamond Dermot
Published: July 2006

A membrane‐based ion‐selective electrode (ISE) has been developed for the trace‐level determination of Cs+ in aqueous samples. A systematic evaluation of several ionophores was performed, examining the effect of membrane plasticizer and ion exchanger on sensor selectivity. Poly(vinyl chloride) (PVC)‐based ion‐selective membranes of conventional composition containing calix[6]arene hexaacetic acid hexaethylester as ionophore (Cs I, 10 mmol/kg), bis(2‐ethylhexyl) sebacate (DOS, 66 wt%) as plasticizer, and undecaiodinated closo‐dodecacarborane (UIC, 4.1 mmol/kg) as ion exchanger exhibited superior performance with respect to selectivity over alkali and alkaline earth metal cations. The unbiased selectivity coefficients, log K$\rm{ {_{Cs,J}^{pot}}}$, for the principal interfering ions (J=K+, Na+, Ca2+, and Mg2+) were determined to be −2.9, −4.7, −8.5, and −8.7, respectively. DOS‐plasticized PVC electrodes containing Cs I and UIC were optimized for trace‐level measurements, exhibiting a lower detection limit of 7.9×10−9 M Cs+ (log aCs,LDL=−8.1) in the presence of a 1×10−5 M Na+ background. The utility of the optimized ISEs was demonstrated by determining the concentration of Cs+ in both drinking water and natural water samples.
Synthesis and Characterization of a Novel, Colored Lipophilic Additive for Spectral Imaging the Transport in Ionophore Based Ion‐Selective Membranes
Authors: Móczár Ildikó , Gyurcsányi Róbert E. , Huszthy Péter , Jágerszki Gyula , Tóth Klára , Lindner Ernő
Published: July 2006

The synthesis and application of a novel colored lipophilic additive (2,4,6‐trinitro‐3‐pentadecylphenol (TNPDP)) as optical tracer for imaging membrane transport is presented. It was found that TNPDP (estimated pKa=5.53) does not dissociate completely in the studied membranes, even in the presence of the highly basic ETH 5294 chromoionophore (pKa=12.0). In voltage polarization experiments the TNPDP compounded, ETH 5294 based membranes behaved similarly to fixed site membranes, i.e., the external field did not induce concentration polarization in TNPDP and the protonated chromoionophore. To interpret this peculiar behavior, original methods have been implemented to i) compare the diffusion properties and determine the diffusion coefficients of multiple species in ion‐selective membranes by hyperspectral imaging, and ii) determine the ion pair formation constant of the ETH 5294 with the novel colored lipophilic anion and a commonly used tetraphenylborate derivative by impedance spectroscopy. Using the “merged membrane” method individual diffusion coefficients of (2.39±0.07)×10−8 cm2/s (N=5), and (2.34±0.02)×10−8 cm2/s (N=2) were determined for the unprotonated form of ETH 5294 and for the undissociated form of TNPDP, respectively. Once in combination with a counter anion, the diffusion coefficient of the protonated ETH 5294 depended on the properties of the lipophilic anion in the membrane. The apparent diffusion coefficient of the protonated ETH 5294 were much smaller when paired with TNPDP ((1.8±0.8)×10−9 cm2/s, N=9) than with tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate (TFPB) ((1.19±0.42)×10−8 cm2/s, N=5). In agreement, the ion pair formation constants of the ETH 5294 with TNPDP (3.14×104 M−1) were almost three orders of magnitude higher than with TFPB (83 M−1).
Amperometric Glucose Biosensor Based on Entrapment of Glucose Oxidase in a Poly(3,4‐ethylenedioxythiophene) Film
Authors: Nien Po‐Chin , Tung Tsai‐Shih , Ho Kuo‐Chuan
Published: July 2006

In this study, conducting polymer, poly(3,4‐ethylenedioxythiophene) (PEDOT), is used as a matrix for the entrapment of glucose oxidase (GOD) and served as the working electrode for sensing glucose. The monomer, EDOT, is electropolymerized onto the platinum electrode by the cyclic voltammetric (CV) technique, scanned between 0.2 and 1.2 V (vs. Ag/AgCl/saturated KCl) in a phosphate buffer solution (PBS) containing GOD, which is entrapped into the PEDOT film simultaneously. The biosensor senses the reoxidative current of the mediator, ferricinium ions, with a constant applied potential of 0.35 V in the sensing system containing a phosphate buffer solution, ferricinium ions, and glucose. The indirect electrochemical method can efficiently reduce the sensing potential of the glucose. The sensing results show that the linear range of the calibration curve for the glucose concentration lies between 0.1 and 10.0 mM, which is a suitable level in the human body. Besides, the limit of detection and sensing sensitivity on glucose for the biosensor are 0.13 mM and 12.42 mA cm−2 M−1, respectively. The response time of the biosensor, which is defined as the reaction current reaching 95% of the steady‐state current, is about 4–10 s. In the aspects of interferences on ascorbic acid (AA) and uric acid (UA), the sensing currents increased about 9.7% and 39.1%, respectively, when compared to the sensing current of glucose. Moreover, the biosensor shows a good stability in which the sensing current of the electrode retains 80% of its original one over a period of 18 days.
Galvanostatic Polarization of All‐Solid‐State K+‐Selective Electrodes with Polypyrrole Ion‐to‐Electron Transducer
Authors: Pawłowski Paweł , Michalska Agata , Maksymiuk Krzysztof
Published: July 2006

Influence of galvanostatic polarizations on potential vs. logarithm of ion activity dependences of all‐solid‐state ion‐selective electrodes with conducting polymer ion‐to‐electron transducer was studied. As a model system K+‐sensor with polypyrrole solid contact and poly(vinyl chloride) based membrane containing valinomycin was chosen. The influence of the lipophilic salt included to the membrane composition was of special interest.
Choosing the parameters of multiple‐repetition strategies
Authors: Veugen Thijs
Published: July 2006

The class of multiple‐repetition strategies is known to achieve capacity for specific discrete memoryless channels with noiseless feedback. We show, given an arbitrary discrete memoryless channel with noiseless feedback, that the repetition parameters should be chosen close to the self information of a transmission error to maximise the transmission rate. Furthermore, it is indicated how close the channel capacity can be approached in the general case. Finally, we compare some results on a related problem: the capacity of a discrete noiseless channel with constraints on the input symbols. Copyright © 2006 AEIT
Energy barriers of proton transfer reactions between amino acid side chain analogs and water from ab initio calculations
Authors: Herzog Elena , Frigato Tomaso , Helms Volkhard , Lancaster C. Roy D.
Published: July 2006

Proton transfer reactions were studied in all titratable pairs of amino acid side chains where, under physiologically reasonable conditions, one amino acid may function as a donor and the other one as an acceptor. Energy barriers for shifting the proton from donor to acceptor atom were calculated by electronic structure methods at the MP2/6‐31++G(d,p) level, and the well‐known double‐well potentials were characterized. The energy difference between both minima can be expressed by a parabola using as argument the donor–acceptor distance R(DA). In this work, the fit parameters of the quadratic expression are determined for each donor–acceptor pair. Moreover, it was found previously that the energy barriers of the reactions can be expressed by an analytical expression depending on the distance between donor and acceptor and the energy difference between donor and acceptor bound states. The validity of this approach is supported by the extensive new data set. This new parameterization of proton transfer barriers between titratable amino acid side chains allows us to very efficiently estimate proton transfer probabilities in molecular modelling studies or during classical molecular dynamics simulation of biomolecular systems. © 2006 Wiley Periodicals, Inc.J Comput Chem 27: 1534–1547, 2006
PROFASI: A Monte Carlo simulation package for protein folding and aggregation
Authors: Irbäck Anders , Mohanty Sandipan
Published: July 2006

We present a flexible and efficient program package written in C++, PROFASI, for simulating protein folding and aggregation. The systems are modeled using an all‐atom description of the protein chains with only torsional degrees of freedom, and implicit water. The program package has a modular structure that makes the interaction potential easy to modify. The currently implemented potential is able to fold several peptides with about 20 residues, and has also been used to study aggregation and force‐induced unfolding. The simulation methods implemented in PROFASI are Monte Carlo‐based and include a semilocal move and simulated tempering. Adding new updates is easy. The code runs fast in both single‐ and multi‐chain applications, as is illustrated by several examples. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1548–1555, 2006
Novel thermostable serine collagenase from Thermoactinomyces sp. 21E: purification and some properties
Authors: Petrova Detelina Hristova , Shishkov Stoyan Angelov , Vlahov Stoyan Stefanov
Published: July 2006

A thermophilic actinomycete strain Thermoactinomyces sp. 21E producing a highly thermostable serine collagenase was isolated from Bulgarian soil. The collagenase, produced extracellular by Thermoactinomyces sp. 21E, was purified to homogeneity by heat treatment, ultrafiltration, saturation with ammonium sulfate and gel filtration chromatography with a 101‐fold increase in specific activity and 58% recovery. The collagenase has a relative molecular mass of 50000 by SDS‐PAGE. The optimum temperature for the enzyme activity was 60–65 °C in the absence of Ca2+ and 70–75 °C in the presence of Ca2+. About 40% of the original activity remaining after incubation at 85 °C for 30 min in the presence of Ca2+. The optimum pH for the enzyme activity was 9.0–9.5 and the enzyme was stable for 1h at 70 °C in the pH range from 7.5 to 12.5. The collagenase was strongly inhibited by active‐site inhibitors of serine protease PMSF and DFP, which indicated that the enzyme is serine protease. The enzyme activity was completely inhibited by Hg2+, Cu2+ and Fe2+. However, Ca2+ strongly activated the collagenase activity. The collagenase from Thermoactinomyces sp. 21E showed high activity toward type I collagen, acid‐soluble collagen, gelatin and Pz‐PLGPR. However, elastin for collagenase was inert as substrate. The properties of the collagenase from strain 21E suggest that this enzyme is a new collagenolytic protease that differs from the collagenases and serine proteases reported so far. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antibacterial activity of the soy isoflavone genistein
Authors: Hong Hyunki , Landauer Michael R. , Foriska Mark A. , Ledney G. David
Published: July 2006

Genistein, a radioprotective soy isoflavone and protein kinase inhibitor, blocks the invasion of pathogenic bacteria in mammalian epithelial cells. The purpose of this study was to evaluate the direct effect of genistein on the survival and growth of the probiotic Lactobacillus reuteri and selected opportunistic bacteria in vitro as a prelude to in vivo use for managing postirradiation sepsis. We evaluated the opportunistic bacterial enteropathogens Escherichia coli, Shigella sonnei, and Staphylococcus aureus as well as Klebsiella pneumoniae and the non‐pathogenic organism, Bacillus anthracis (Sterne). The latter two bacteria are found in the environment and may be of concern in irradiated individuals. A standard in vitro test was employed to evaluate the direct effect of genistein on the bacteria. This test involved determining bacterial colony forming unit (CFU) counts at a single concentration of genistein. In the CFU assays, significant reductions in CFUs were found for S. aureus and B. anthracis when cultured in the presence of 100 μM genistein. However, L. reuteri, E. coli, S. sonnei, and K. pneumoniae were not altered by in vitro culturing in the presence of 100 μM genistein. These results demonstrate the in vitro antimicrobial activity of genistein. Furthermore, the use of genistein in combination with probiotics may augment the effectiveness of antimicrobial therapies currently used in the management of infections, including those induced by ionizing irradiation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auxotrophic mutant of the cyanobacterium Nostoc muscorum showing absolute requirement of Cs+ or Rb+ for diazotrophy and autotrophy
Authors: Bhargava Santosh , Chauhan Rajendra , Patil Pramod K. , Singh Sarva Daman
Published: July 2006

Caesium‐resistant (Cs+‐R) mutant clones of the cyanobacterium Nostoc muscorum were characterized for diazotrophic growth in a medium devoid of Cs+ or Rb+ or both. Cs+‐R phenotype suffered severe genetic damage of a pleiotropic nature affecting diazotrophic growth, chlorophyll a content, nitrogenase activity and photosynthetic O2 evolution. Mutation leading to development of Cs+‐R phenotype could be overcome by availability of Cs+/Rb+. Parent and mutant strains were similar with respect to their Cs+/Rb+ uptake. Available data suggests operation of an efficient coupling of the two incompatible reactions viz. oxygenic photosynthesis and oxygen sensitive N2 fixation in this cyanobacterium. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Purification and characterization of a halotolerant intracellular protease from Bacillus subtilis strain FP‐133
Authors: Setyorini Endang , Kim Young‐Ju , Takenaka Shinji , Murakami Shuichiro , Aoki Kenji
Published: July 2006

A halotolerant strain FP‐133, able to grow at concentrations of 0–12.5% (w/v) NaCl, was isolated from a fish paste and identified as Bacillus subtilis . B. subtilis strain FP‐133 produced an intracellular protease which showed catalytic activity under saline conditions. The enzyme was purified to homogeneity 143‐fold with a yield of 0.9%. The purified enzyme showed an optimum activity at a concentration of 5% (w/v) NaCl. After storage in 7.5% (w/v) NaCl at 4 °C for 24 h, the enzyme kept 100% of its activity. The molecular mass of the protease was determined to be 59 kDa by gel filtration; the protein consisted of four subunits each with a molecular mass of 14 kDa. The enzyme showed aminopeptidase activity. It acted on l‐leucyl‐p ‐nitroanilide, l‐leucyl‐β‐naphthylamide, and oligopeptides containing glycine, l‐histidine, or l‐leucine. The Km and V max values for l‐leucyl‐p ‐nitroanilide were 18 µm and 2.2 mm/h mg, respectively. The enzyme was activated by Fe2+, Fe3+, and Ni2+ in synergism with Mg2+. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infectivity of soilborneFrankiaand mycorrhizae inDiscaria trinervisalong a vegetation gradient in Patagonian soil
Authors: Chaia Eugenia Esther , Fontenla Sonia Beatriz , Vobis Gernot , Wall Luis Gabriel
Published: July 2006

The infective capacities of the nitrogen fixing ActinomyceteFrankiaand arbuscular mycorrhizal fungi from soils near watercourses, along a vegetation gradient, were studied using plant bioassays.Frankiaand arbuscular mycorrhizas capable of infectingDiscaria trinerviswere found at seventeen sites sampled. More specific enumeration of the infective capacities of both microorganisms in relation to environmental factors was performed in seven representative soils of the analysed vegetation zones (rainforest, xeric forest and steppe) using the most probable number method. The highest nodulation capacities ranged from 340 infective units g–1soil, in a steppe marsh devoid of actinorhizas, to 61 in a coastal actinorhizal scrub (in xeric forest). The highest number of infective mycorrhizal units – also found in marsh – was 145. In general, rainforest soils had the lowest values for both microorganisms. Infective units ofFrankiaand arbuscular mycorrhizal fungi in soil were positively correlated (r= 0.89,P< 0.05). Both soilborne symbionts showed the highest infective capacity in semi‐arid conditions nearby watercourse and at the valley bottom location. Tripartite symbiosis was effective in plants inoculated with steppe and xeric forest soils and plants inoculated withFrankiaBCU110501 andGlomus mosseae.Interaction between both symbionts and influence of environmental conditions, in general, would contribute to define comparable trends of their infective capacities. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Incidence of Leptosphaerulina crassiasca in symptomless leaves of peanut in southern India
Authors: Suryanarayanan Trichur S. , Murali Thokur S.
Published: July 2006

A Loculoascomycete fungus belonging to the genus Leptosphaerulina was found to survive as symptomless endophyte in the leaflets and rachis of peanut plant (TMV 7). Based on morphological and colony characteristics, it is identified as Leptosphaerulina crassiasca, a fungus that causes the pepper spot and leaf scorch diseases in peanut. Although several common endophytic fungi were recovered from the leaves of peanut, L . crassiasca showed a high relative density of infection. Owing to its endophytic nature, its pathogenicity could not be proved by infection studies. However, its identification as L. crassiasca suggests that this pathogen survives as symptomless endophyte in its host. There are limited studies on fungal endophytes of cultivated crops and hence, the present observation underlines the need to know more about the biology of endophytic fungi of crop plants. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)