bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repeated exposures to gustatory stimuli produce habituation or positive contrast effects in perinatal rats
Authors: Mickley G. Andrew , Kenmuir Cynthia L. , Dengler‐Crish Christine M. , McMullen Colleen , McConnell Anna , Valentine Elizabeth 
Published: March 2004

AbstractAdult rats exhibit a decrease in consummatory responses following repeated presentations of a taste (habituation) and an increase in consummatory responses if they experience an upward shift in the magnitude or intensity of a gustatory stimulus (e.g., sucrose or saccharin). These responses do not represent a direct sensorimotor reaction to a gustatory cue, but rather reflect a change in responding based on the memory of a previous taste. Here, we sought to determine if fetal rats could (like adults) adjust their orofacial motor responses based on a memory of recent gustatory experience. Embryonic Day 18 (E18) or Day 19 (E19) rat fetuses received oral lavage with either 0.15 or 0.30% saccharin (SAC). Subsequently, observations of orofacial movements (mouthing and licking) following oral lavage with 0.30% SAC were made 50 min later, 24 hr later, or on postnatal Day 3 (P3). Thus, some animals were in a “shifted” condition in which they first experienced a relatively low concentration of SAC and then a higher one while control rats (“nonshifted”) received 0.30% SAC during both taste exposures. Fetuses exhibited evidence of both habituation (with repeated presentation of the 0.30% SAC) and positive contrast effects (PCEs) (following an upward shift in SAC concentration) when retested 50 min after their first exposure to SAC on E19. However, these animals did not exhibit PCEs 24 hr later or 5 days later (on P3). Contrast effects were not observed when the initial SAC exposure was on E18, and habituation responses were variable depending on the time interval between the taste presentations to these animals. Rats with a 5‐ to 6‐day latency between the two taste presentations showed neither PCEs nor habituation. Our data indicate that PCEs and habituation effects emerge at different ages, and their demonstration is dependent upon the latency between the taste presentations. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 176–188, 2004.
The First (Trisulfoxide)metal Complexes: Synthesis and Crystal Structures of the 1D Lanthanide Coordination Polymers [Ln(L)(MeOH)(NO3)3]n and {[La(L)(DMF)5](ClO4)3}n [L = 1,3,5‐Tris(ethylsulfinyl)‐2,4,6‐trimethylbenzene, Ln = LaIII and NdIII]
Authors: Li Jian‐Rong , Bu Xian‐He , Zhang Ruo‐Hua 
Published: March 2004

AbstractA new trisulfoxide ligand, 1,3,5‐tris(ethylsulfinyl)‐2,4,6‐trimethylbenzene (L), was designed and synthesized, and treated with Ln(NO3)3 or Ln(ClO4)3 to produce three coordination polymers: [Ln(L)(MeOH)(NO3)3]n [where Ln = LaIII (1); NdIII (2)] and {[La(L)(DMF)5](ClO4)3}n (3). Solid‐state structures of all three complexes were determined by single‐crystal X‐ray diffraction. The three complexes have 1D helical‐chain structures and complexes 1 and 2 are isostructural. To the best of our knowledge, these coordination polymers are the first examples of (trisulfoxide)metal complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Enantioselective Routes to Sulfoxides Based Upon the Use of Carbanionic Leaving Groups
Authors: Capozzi Maria Annunziata M. , Cardellicchio Cosimo , Naso Francesco 
Published: March 2004

AbstractSeveral carbanionic leaving groups can be easily displaced from the sulfinyl group by organometallic reagents. The reaction follows a highly stereoselective course of inversion of configuration. Provided that a ready route to the precursor sulfinyl compound is available (e.g. an enantioselective oxidation of the corresponding sulfide), the process can be transformed into an easy and versatile procedure for the stereoselective synthesis of sulfoxides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Superstructured Porphyrins as Effectors in Dynamic Supramolecular Assemblies: Receptors, Rotaxanes and Catenanes
Authors: Gunter Maxwell J. 
Published: March 2004

AbstractThe development of porphyrinic systems specifically functionalised to recognise photoactive and electroactive substrates has been a study in the evolution of supramolecular assemblies, from receptors, through pseudorotaxanes to catenanes, to thermodynamically‐controlled synthesis, and eventually to solid‐appended self‐assembling supermolecules. We describe how crown ether‐capped porphyrins act as efficient receptors for bipyridinium dications, where the complexes have an in‐built addressability through the porphyrin, and are monitored through physical and chemical stimuli. Conceptual extension allows production of porphyrin[2]‐ and ‐[3]‐catenanes, and a series of these offers opportunities for a structure‐activity profile through a variety of dynamic processes, including motional, translational, chemical (acid/base), photochemical and electrochemical methods. Related design concepts extend the study into neutrally‐charged diimide‐based catenanes. The recognition processes responsible for their synthesis have then been extended into equilibrating conditions, so that the thermodynamically most favourable rotaxanes can be assembled by simple mixing of components. Finally, these concepts have led to the direct real‐time study by gel‐phase HRMAS methodology of the self‐assembly of porphyrin rotaxanes on polymer supports, under equilibrating conditions between solid and solution phases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A New Procedure for Voltammetric Lead Determination Based on Coprecipitation and Centrifugation Preconcentration
Authors: Kirgöz Ülkü Anik , Tural Hüseyin , Ertas F. Nil 
Published: March 2004

AbstractAn arrangement of a voltammetric cell specially designed to be compatible to both centrifugation and voltammetry was designed, allowing direct measurement without any need for dissolution or filtration steps. The procedure for the preconcentration via coprecipitation is described. The system was succesfully tested using trace amounts of Pb(II) ions in aqueous solution preconcentrated with Al(OH)3 as the carrier precipitate and resulting peak currents were found much higher than those without applying centrifugation. The effects of the parameters on the resulting signal were examined and the detection limit was found as 2.2×10−9 M.
Investigation by QCM of the Specific and Nonspecific Avidin Interaction onto a Biotinylated Polypyrrole Film
Authors: Dupont‐Filliard A. , Billon M. , Bidan G. , Guillerez S. 
Published: March 2004

AbstractWe have studied by gravimetric measurements using a quartz crystal microbalance (QCM), the adsorption of avidin onto a polypyrrole film. From QCM results, it appears that both the thickness and the redox state of polypyrrole strongly influence the avidin adsorption. This nonspecific interaction is larger for a thick film than for a thin one and, also for when the polymer is in its reduced state. We have also investigated by QCM the specific and nonspecific interaction of avidin onto biotinylated polypyrrole films having either a hydrophilic or hydrophobic character. It is shown that the amount of avidin immobilized by specific recognition is almost the same whatever the nature of the polymer matrix.
Rapid Electrochemical Detection of Propranolol and Metoprolol in Pharmaceutical Preparations Using Stabilized Lipid Films
Authors: Nikolelis Dimitrios P. , Mitrokotsa Maria 
Published: March 2004

AbstractThis work reports a technique for the rapid electrochemical detection of propranolol and metoprolol in pharmaceutical preparations using stabilized lipid films. Microporous filters composed of glass fibers (nominal pore sizes 0.7 and 1.0 μm) were used as supports for the formation and stabilization of these devices. The lipid film is formed on the filter by polymerization prior to its use. This stabilized after storage in air. Lipid films composed of phosphatidylcholine were used for the detection of propranolol and metoprolol in pharmaceutical preparations. The stabilized lipid membranes provided artificial ion gating events in the form of transient signals within about 60 and 34 s after exposure of the membranes to propranolol and metoprolol, respectively. The magnitude of the transient current signal was related to the concentration of propranolol and metoprolol in bulk solution in the micromolar range. The mechanism of signal generation was investigated by differential scanning calorimetric studies. These studies revealed that the adsorption of the drug is through the hydrophobic aryl terminal of the compound, whereas the hydrophilic groups were directed towards the electrolyte solution. This adsorption caused a rapid alteration of the electrochemical double layer of the lipid film (i.e., capacitance changes) that resulted in the transient ion current signal. The present technique was used for the rapid detection of propranolol and metoprolol in pharmaceutical preparations and can function for repetitive uses after storage in air. Future research is targeted to the determination of these chemicals in human biofluids such as urine of athletes.
Maintenance of Soft Calibration Models in the Determination of Zinc, Cadmium, Lead and Copper by Differential Pulse Anodic Stripping Voltammetry
Authors: Sanz M. Belén , Sarabia Luis A. , Herrero Ana , Ortiz M. Cruz 
Published: March 2004

AbstractA strategy for constructing a global multivariate calibration model that includes calibration samples measured over time on different days is developed and applied in electroanalysis. Both synthetic and real samples (tap, extracted and river water) are analyzed by differential‐pulse anodic stripping voltammetry, showing the suitability of the global model constructed that provides successful results similar to those of the usual multivariate calibration. In addition the capability of discrimination of this model is evaluated in prediction for the mean of three replicates with estimation of probability of false noncompliance, α, and false compliance, β, being found 3.1, 11.2, 6.7 and 64.7 nM for nominal concentrations of zinc, cadmium, lead and copper of 96.0, 40.4, 37.3 and 328.0 nM respectively when α=β=0.05. It has been proven that the use of the global calibration does not imply a loss of multivariate analytical sensitivity, using this parameter as quality index of the analytical procedure. The viability of using calibration maintenance strategies with electroanalytical techniques is shown, providing a way to save time and experimental effort when these techniques are used in routine analysis.
Elucidation of the Electrochemical Oxidation Pathway of Ammonia in Dimethylformamide and the Room Temperature Ionic Liquid, 1‐Ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide
Authors: Buzzeo Marisa C. , Giovanelli Debora , Lawrence Nathan S. , Hardacre Christopher , Seddon Kenneth R. , Compton Richard G. 
Published: March 2004

AbstractThe direct electrochemical oxidation of ammonia has been examined in both the organic solvent dimethylformamide (DMF) and the room temperature ionic liquid 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][N(Tf)2]. The corresponding voltammetric responses have been shown to be similar in each solvent with a broad oxidative wave occurring upon the introduction of ammonia to the solution and the appearance of a new reductive wave following the oxidation. The oxidative reaction process has been examined and a suitable reaction pathway has been deduced, corresponding to the formation of ammonium cations after oxidation of the ammonia. A linear response of limiting current against vol% ammonia was observed in both DMF and [EMIM][N(Tf)2], suggesting potential application for analytical methods.
Analysis and Speciation of Traces of Arsenic in Environmental, Food and Industrial Samples by Voltammetry: a Review
Authors: Cavicchioli Andrea , La‐Scalea Mauro A. , Gutz Ivano G. R. 
Published: March 2004

AbstractVoltammetric approaches for the determination of arsenic and speciation at trace levels are critically appraised in a review covering the literature from 1970 to 2002. Special attention is devoted to stripping modes and to issues related to the choice of working material and supporting electrolyte. A section is dedicated to the management of real samples and aspects of sample preparation. An extensive compilation, organized by real sample type, gathers essential experimental conditions. Potentiometric stripping analysis is introduced for sake of comparison. The coupling of voltammetric detection or preaccumulation with FIA, chromatography, capillary electrophoresis and ICP techniques is also addressed.
Evaluation of a PVC‐Based Thionine‐Zeolite and Zeolite Free Membranes as Sensing Elements in Ion Selective Electrode
Authors: Sohrabnejad Shabnam , Zanjanchi Mohammad A. , Arvand Majid , Mousavi Mir F. 
Published: March 2004

AbstractThe construction and performance characteristics of thionine electrodes based on the ion‐pair complex thionine‐tungstophosphate and thionine‐mordenite zeolite embedded in a polyvinyl chloride (PVC) matrix is described. Thionine electrode based on the ion‐pair is used for the indirect determination of ascorbic acid by standard addition method.
Indirect Measurement of Yoctomole Alkaline Phosphatase by Capillary Electrophoresis with Electrochemical Detection
Authors: Sun Xuemei , Weng Qianfeng , Jin Wenrui 
Published: March 2004

AbstractA method for indirectly detecting yoctomole (ymol) alkaline phosphatase was developed by capillary electrophoresis with electrochemical detection. In this method, disodium phenyl phosphate was used as the enzyme substrate and the product (phenol) of its hydrolysis reaction catalyzed by alkaline phosphatase was detected at the carbon fiber electrode. The optimum conditions of detection are 1.0×10−2 mol/L Na2B4O7 (pH 9.8) for the running buffer; 1.00×10−3 mol/L disodium phenyl phosphate for the enzyme substrate; 20.0 kV for the separation voltage; 5 kV and 10 s for the injection voltage and injection time; 1.05 V (vs. saturated calomel electrode) for the detection potential and 10 min for the incubation time, respectively. In order to enhance the ratio of signal to noise, the shape and size of the working electrode, the shape of detection end of the capillary, and the capillary/electrode alignment method were studied in detail. When a single carbon fiber microcylinder electrode of 6 μm, a capillary of 10 μm ID with the etched detection end and the in‐capillary alignment were used, a ymol mass limit of detection for alkaline phosphatase was achieved.
Integrated Microanalytical System Coupling Permeation Liquid Membrane and Voltammetry for Trace Metal Speciation. Technical Description and Optimization
Authors: Salaun P. , Bujard F. , Berdondini L. , Koudelka‐Hep M. , Buffle J. 
Published: March 2004

AbstractA new minicell coupling the liquid‐liquid extraction technique called permeation liquid membrane (PLM) with an integrated Ir‐based Hg‐plated microelectrode array for voltammetric detection has been developed for the speciation of heavy metals in natural waters. Lead and cadmium have been used as model compounds. The PLM consists of a carrier (0.1 M 22DD+0.1 M lauric acid) dissolved in 1 : 1 mixture of toluene/phenylhexane held in the small pores (30 nm) of a hydrophobic polypropylene membrane (Celgard 2500). One side of this membrane is in contact with a flowing source solution, containing the metal ions of interest. An acceptor or strip solution (pyrophosphate) is placed on the other side of the PLM with the microelectrode array placed at 480 μm of the PLM. The analyte is transported by the carrier from the source solution to the strip solution. The originality of the new minicell is that accumulation in the strip solution is voltammetrically followed by the integrated microelectrode array in real time, and at low concentration level, using square‐wave anodic stripping voltammetry (SWASV). In order to protect the Hg microelectrodes from the adsorption of the hydrophobic carrier, the microelectrodes are embedded in a thin gel layer (280 μm) of 1.5% LGL agarose gel containing 10% of hydrophobic silica particles C18. The choice of optimum conditions is discussed in details in this article. Due to the very small effective strip volume of the new cell (less than 1 μL), high enrichment factor can be obtained (e.g., 330 for Pb) after 2 hours of accumulation. No deaeration of the solutions is required for SWASV measurements. Detection limits under these conditions are 2 pM and 75 pM for Pb and Cd, respectively, using a voltammetric deposition time of 5 min. In addition, no fouling effects were observed with natural water samples.
LES of turbulent heat transfer: proper convection numerical schemes for temperature transport
Authors: Châtelain A. , Ducros F. , Métais O. 
Published: March 2004

AbstractLarge eddy simulations of two basic configurations (decay of isotropic turbulence, and the academic plane channel flow) with heat transfer have been performed comparing several convection numerical schemes, in order to discuss their ability to evaluate temperature fluctuations properly. Results are compared with the available incompressible heat transfer direct numerical simulation data. It is shown that the use of regularizing schemes (such as high order upwind type schemes) for the temperature transport equation in combination with centered schemes for momentum transport equation gives better results than the use of centred schemes for both equations. Copyright © 2004 John Wiley & Sons, Ltd.
Affected‐sib‐pair test for linkage based on constraints for identical‐by‐descent distributions corresponding to disease models with imprinting
Authors: Knapp Michael , Strauch Konstantin 
Published: March 2004

AbstractHolmans' possible triangle test for affected sib pairs has proven to be a powerful tool for linkage analysis. This test is a likelihood‐ratio test for which maximization is restricted to the set of possible sharing probabilities. Here, we extend the possible triangle test to take into account genomic imprinting, which is also known as parent‐of‐origin effect. While the classical test without imprinting looks at whether affected sib pairs share 0, 1, or 2 alleles identical‐by‐descent, the likelihood‐ratio test allowing for imprinting further distinguishes whether the sharing of exactly one allele is through the father or mother. Thus, if the disease gene is indeed subject to imprinting, the extended test presented here can take into account that affecteds will have inherited the mutant allele preferentially from one particular parent. We calculate the sharing probabilities at a marker locus linked to a disease susceptibility locus. Using our formulation, the constraints on these probabilities given by Dudoit and Speed ([1999] Statistics in Genetics; New York: Springer) can easily be verified. Next, we derive the asymptotic distribution of the restricted likelihood‐ratio test statistic under the null hypothesis of no linkage, and give LOD‐score criteria for various test sizes. We show, for various disease models, that the test allowing for imprinting has significantly higher power to detect linkage if imprinting is indeed present, at the cost of only a small reduction in power in case of no imprinting. Altogether, unlike many methods currently available, our novel model‐free sib‐pair test adequately models the epigenetic parent‐of‐origin effect, and will hopefully prove to be a useful tool for the genetic mapping of complex traits. © 2004 Wiley‐Liss, Inc.
Separating phonological and semantic processing in auditory sentence processing: A high‐resolution event‐related brain potential study
Authors: D'Arcy Ryan C.N. , Connolly John F. , Service Elisabet , Hawco Colin S. , Houlihan Michael E. 
Published: March 2004

AbstractPhonological and semantic processing was studied using high‐resolution event‐related brain potentials (ERPs) during a sentence‐matching task to investigate the spatial distribution of the phonological mismatch negativity (PMN) and the N400 response. It was hypothesized that the two components were spatially separable and that the activity matched prior localization knowledge. Participants examined visual–auditory sentence pairs that related within a semantic hierarchy (e.g., visual: “The man is teaching in the classroom”; Auditory: “The man is in the…school/barn”). Semantic congruency was varied for the final words of the spoken sentences. Incongruent words mismatched expectation in terms of both the initial phonological features (unexpected sound) and semantic features (unexpected meaning). In addition, the category–exemplar probability of the final words was either high or low, with low probability words being more difficult to anticipate. Low probability words were predicted to selectively affect PMN activity. We found that incongruent words elicited a PMN (287 msec) and a N400 (424 msec), for both the high and low probability words. As expected, low probability congruent words elicited a small PMN but no N400. In contrast, high probability congruent words elicited neither a detectible PMN nor a N400. The primary PMN sources were in left inferior frontal and inferior parietal lobes. The primary N400 source activation occurred along the left perisylvian cortex, consistent with prior N400 source localization work. From these results, it was concluded that the PMN and N400 were localized to separate cortical language (and memory) regions and had different source activation patterns. Hum. Brain Mapping 22:42–53, 2004. © 2004 Wiley‐Liss, Inc.