bluuebunny/crossref_metadata_2025 huggingface dataset:
Paint‐assisted microdissection‐FISH: Rapid and simple mapping of translocation breakpoints in the embryonal rhabdomyosarcoma cell line RD
Authors: Roberts Ian , Foster Nicola , Nacheva Elisabeth , Coleman Nicholas
Published: March 2004

Background

Spectral karyotyping and multiple fluorophore fluorescence in situ hybridisation (M‐FISH) facilitate identification of inter‐chromosomal rearrangements, but are of low cytogenetic resolution in mapping translocation breakpoints. Reverse chromosome painting yields increased cytogenetic information but isolation of aberrant chromosomes is technically difficult. We have developed the technique of paint‐assisted microdissection FISH (PAM‐FISH), which enables microdissection of aberrant chromosomes to be carried out easily and rapidly using relatively simple apparatus.

Methods

A selected chromosome paint is hybridised to abnormal metaphases to label a chromosome of interest, which is then microdissected, amplified, labelled by polymerase chain reaction (PCR), and reverse painted onto extended normal metaphases.

Results

PAM‐FISH was used to reassess structural chromosomal abnormalities identified by molecular cytogenetics in the rhabdomyosarcoma cell line RD. PAM‐FISH improved the analysis of virtually all structural abnormalities, identifying six novel translocations and indicating that seven previously described rearrangements were in fact not present in RD. Accuracy of the breakpoint mapping obtained was confirmed by bacterial artificial chromosome‐FISH.

Conclusions

PAM‐FISH is ideally suited to analysis of tumour metaphases as it is not affected by poor chromosome morphology. Reagents generated by PAM‐FISH are also suitable for other investigations, such as mapping using sequence tagged‐site PCR or genomic microarrays. PAM‐FISH is technically straightforward and could readily be adopted in a routine cytogenetics laboratory for accurate high‐throughput analysis of chromosome breakpoints. © 2004 Wiley‐Liss, Inc.
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

Adult 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

A 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

Several 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

The 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

An 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

We 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

This 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

A 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

The 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

Voltammetric 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

The 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

A 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

A 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

Large 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

Holmans' 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

Phonological 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.
Multimodal integration of EEG and MEG data: A simulation study with variable signal‐to‐noise ratio and number of sensors
Authors: Babiloni Fabio , Babiloni Claudio , Carducci Filippo , Romani Gian Luca , Rossini Paolo M. , Angelone Leonardo M. , Cincotti Febo
Published: March 2004

Previous simulation studies have stressed the importance of the multimodal integration of electroencephalography (EEG) and magnetoencephalography (MEG) data in the estimation of cortical current density. In such studies, no systematic variations of the signal‐to‐noise ratio (SNR) and of the number of sensors were explicitly taken into account in the estimation process. We investigated effects of variable SNR and number of sensors on the accuracy of current density estimate by using multimodal EEG and MEG data. This was done by using as the dependent variable both the correlation coefficient (CC) and the relative error (RE) between imposed and estimated waveforms at the level of cortical region of interests (ROI). A realistic head and cortical surface model was used. Factors used in the simulations were: (1) the SNR of the simulated scalp data (with seven levels: infinite, 30, 20, 10, 5, 3, 1); (2) the particular inverse operator used to estimate the cortical source activity from the simulated scalp data (INVERSE, with two levels, including minimum norm and weighted minimum norm); and (3) the number of EEG or MEG sensors employed in the analysis (SENSORS, with three levels: 128, 61, 29 for EEG and 153, 61, or 38 in MEG). Analysis of variance demonstrated that all the considered factors significantly affect the CC and the RE indexes. Combined EEG–MEG data produced statistically significant lower RE and higher CC in source current density reconstructions compared to that estimated by the EEG and MEG data considered separately. These observations hold for the range of SNR values presented by the analyzed data. The superiority of current density estimation by multimodal integration of EEG and MEG was not due to differences in number of sensors between unimodal (EEG, MEG) and combined (EEG–MEG) inverse estimates. In fact, the current density estimate relative to the EEG–MEG multimodal integration involved 61 EEG plus 63 MEG sensors, whereas estimations carried out with the single modalities alone involved 128 sensors for EEG and 153 sensors for MEG. The results of the simulations also suggest that the use of simultaneous 29 EEG sensors during the MEG measurements carried out with full sensor arrangements (153 sensors) returned an accuracy of the cortical source estimate statistically similar to that obtained by combining 64 EEG and 153 MEG sensors. Hum. Brain Mapp. 22:54–64, 2004. © 2004 Wiley‐Liss, Inc.
Modulation of functional connectivity during the resting state and the motor task
Authors: Jiang Tianzi , He Yong , Zang Yufeng , Weng Xuchu
Published: March 2004

Quite a few studies in functional magnetic resonance imaging (fMRI) have tested that, even in a resting state, motor cortices constitute a network. It has never been investigated how the network modulates from the resting state to the motor task state. In this report, by a newly developed approach taking into account n‐to‐1 connectivity using 1‐to‐1 connectivity measures instead of conventional pairwise connectivity, we show the existence of a large organized functional connectivity network related to motor function in the resting brain with fMRI. More importantly, we found that such a network can be modulated from a conscious resting state to planning, initiation, coordination, guidance, and termination of voluntary movement state, exhibited by significant changes of functional connectivity of some brain regions in different brain activity. Moreover, a quantitative description of such a functional modulation has also been presented. Hum. Brain Mapp. 22:65–73, 2004. © 2004 Wiley‐Liss, Inc.
Noninvasive optical imaging in the visual cortex in young infants
Authors: Kusaka Takashi , Kawada Kou , Okubo Kensuke , Nagano Keiko , Namba Masanori , Okada Hitoshi , Imai Tadashi , Isobe Kenichi , Itoh Susumu
Published: March 2004

During the developmental stage, the brain undergoes anatomic, functional, and metabolic changes necessary to support the complex adaptive behavior of a mature individual. Estimation of developmental changes occurring in different regions of the brain would provide a means of relating various behavioral phenomena to maturation‐specific brain structures, thereby providing useful information on structure‐function relationships in both normal and disease states. We used multichannel near‐infrared spectroscopy (MNIRS), a new noninvasive imaging technique for revealing the course of neural activity in selected brain regions, to monitor the activities of the visual cortex as mirrored by hemodynamic responses in infants subjected to photostimulation during natural sleep. In the infants, oxyhemoglobin and total hemoglobin decreased and deoxyhemoglobin increased in the visual cortex with photostimulation. This pattern of responses was different from the response pattern in adults reported previously. The different patterns of responses to photostimulation in the visual cortices of infants and adults might reflect developmental and behavioral differences. It may reflect a different functional organization of the visual cortex in infants or ongoing retinal development. Our results demonstrated that regional hemodynamic change could be detected in a small area around the visual cortex. MNIRS offers considerable potential for research and noninvasive clinical applications. Hum. Brain Mapping 22:124–134, 2004. © 2004 Wiley‐Liss, Inc.
Novel 2‐phosphabicyclo[2.2.2]oct‐5‐ene derivatives and their use in phosphinylations
Authors: Keglevich György , Kovács János , Körtvélyesi Tamás , Parlagh Gyula , Imre Tímea , Ludányi Krisztina , Hegedűs László , Hanusz Miklós , Simon Kálmán , Márton Andrea , Marosi György , Tőke László
Published: March 2004

The [4 + 2] cycloaddition of the double‐bond isomers (A and B) of dihydrophosphinine oxide 1 afforded novel phosphabicyclo[2.2.2]oct‐5‐ene derivates (2–4), formation of which was justified by PM3 semiempirical calculations. The compounds of dimer type (2–4) were utilized in the UV light‐mediated fragmentation‐related phosphinylation of nucleophiles, especially in that of alcohols. To explore the role of structural modifications on the fragmentation ability, disulfide 5, phosphabicyclooctane 7 obtained by the hydrogenation of 2, and the adduct of dihydrophosphinine oxide 1 with benzoquinone (7) were also synthesized and tested in fragmentation. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:97–106, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10221
An iterative strategy for the synthesis of oligothiophenes by catalytic cross‐coupling reactions
Authors: Pinault Thomas , Chérioux Frédéric , Therrien Bruno , Süss‐Fink Georg
Published: March 2004

An iterative strategy for the synthesis of new sulfur‐functionalized oligothiophenes by Suzuki or Stille cross‐coupling reactions was applied to the reaction of 4‐bromo‐tert‐butylphenylthioether with thiophene derivatives. The planarity of the oligothiophenes obtained was confirmed by the single‐crystal X‐ray structure analysis of 2‐(4′‐tert‐butylthiophenyl)thiophene, which shows a potentially large electronic conjugation length. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:121–126, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10224
Chromophoric macrocycles from the oxidation of bis(aminofurazanylic) ethers of 1,2‐diols
Authors: Sheremetev Aleksei B. , Shatunova Elena V. , Averkiev Boris B. , Dmitriev Dmitrii E. , Petukhov Viktor A. , Antipin Mikhail Yu.
Published: March 2004

A series of chromophoric azofurazan‐containing macrocycles 6a–c and 7a–d were synthesized from bis(aminofurazanylic) ethers of 1,2‐diols 4a–d by dibromoisocyanurate oxidation. The macrocycle closure is a result of NN bond formation. An ion‐binding ability of these compounds was tested. The macrocycles were characterized by NMR, MS, IR, and UV spectroscopy. The X‐ray crystal structures of the macrocycles 6a, 7c, and linear counterpart 12 are reported. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:131–145, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10226
1‐(Arylalkyl)quinolizidine Derivatives and Thio‐Isosteric Analogues as Ligands for Sigma Receptors
Authors: Sparatore Anna , Novelli Federica , Sparatore Fabio
Published: March 2004

A set of 1‐(arylalkyl)quinolizidines, isosteric thioanalogues, and variously functionalized congeners were synthesized (see 1–25) and tested for affinity to sigma 1 and sigma 2 receptor subtypes, by displacing [3H]‐ (+)‐pentazocine and [3H]DTG from guinea pig brain and rat brain preparations, respectively. All compounds exhibited a good affinity for the σ1 subtype, with subnanomolar Ki values for the best of them, while only modest or poor affinity for the σ2 subtype was observed (Tables 1 and 2). Some structureactivity relationships were put forward.
Phenyl and Phenylethyl Glycosides from Picrorhiza scrophulariiflora
Authors: Huang Sheng‐Xiong , Liao Xun , Nie Quan‐Jiang , Ding Li‐Sheng , Peng Shu‐Lin
Published: March 2004

Three new phenyl glycosides, scrophenoside A (1), B (2), and C (3), and two new phenylethyl glycosides, scroside D (4) and scroside E (5), were isolated from the stem of Picrorhiza scrophulariiflora Pennell (Scrophularlaceae), besides five known compounds. On the basis of spectroscopic evidence, the structures of the new compounds were elucidated as 4‐acetyl‐2‐methoxyphenyl 6‐O‐[4‐(β‐D‐glucopyranosyloxy)vanilloyl]‐β‐D‐glucopyranoside (1), 4‐acetylphenyl 6‐O‐[(E)‐p‐coumaroyl]‐β‐D‐glucopyranoside (2), 4‐[(1R)‐ and (1S)‐1‐hydroxyethyl]‐2‐methoxyphenyl β‐D‐glucopyranoside (3a and 3b, resp.), 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D‐glucopyranosyl‐(1→3)‐4‐O‐[(E)‐feruloyl]‐β‐D‐glucopyranoside (4), and 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D‐glucopyranosyl‐(1→3)‐6‐O‐[(E)‐feruloyl]‐β‐D‐glucopyranoside (5).
New Types of Very Efficient Photolabile Protecting Groups Based upon the [2‐(2‐Nitrophenyl)propoxy]carbonyl (NPPOC) Moiety
Authors: Bühler Sigrid , Lagoja Irene , Giegrich Heiner , Stengele Klaus‐Peter , Pfleiderer Wolfgang
Published: March 2004

Based upon the photolabile [2‐(2‐nitrophenyl)propoxy]carbonyl group (NPPOC), a large number of modified 2‐(2‐nitrophenyl)propanol derivatives substituted at the phenyl ring (see 23–34 and 57–76) as well as at the side‐chain (see 85–92 and 95–98) were synthesized to improve the photoreactivity of this new type of photolabile entity. The phenyl moiety was also exchanged by the naphthalenyl group (see 102, 103, 105, 108, 110, 113, and 114), the thienyl substituent (see 115, 117, 118, and 120), and the benzothienyl substituent (see 121). The 2‐(2‐nitroaryl‐ and heteroaryl)propanols were converted with diphosgene into the corresponding carbonochloridates, which reacted subsequently with thymidine to the thymidine 5′‐(protected carbonates) 123–178 as the main reaction products. In several cases, the corresponding 3′‐carbonates and 3′,5′‐dicarbonates 179–212 were also isolated and characterized. Photolysis studies under standardized conditions (see Table) indicated that the rate of photocleavage varies in a broad range depending on the substituents. So far, the thymidine 5′‐[2‐(5‐halo‐2‐nitrophenyl)propyl carbonates] 127–129, 5′‐[2‐(nitro[1,1′‐biphenyl]3‐yl)propyl carbonates] 136–139, 5′‐{2‐[2‐nitro‐5‐(thianthren‐1‐yl)phenyl]propyl carbonate} (140), 5′‐[2‐(5‐naphthalenyl‐2‐nitrophenyl)propyl carbonates] 141 and 142, and 5′‐[2‐(2‐nitro‐5‐thienylphenyl)propyl carbonates] 143 and 144 showed the best properties regarding fast and uniform deprotection. Since the nucleobases of 213–215 do not influence the photocleavage features, in general, the new type of photolabile building blocks allows in form of their 3′‐phosphoramidites the photolithographic formation of high‐quality biochips.
Four New Diterpenoids from Ballota limbata
Authors: Ahmad Viqar Uddin , Farooq Umar , Abbaskhan Ahmed , Hussain Javid , Abbasi Muhammad Athar , Nawaz Sarfraz Ahmad , Choudhary M. Iqbal
Published: March 2004

Six diterpenoids (1–6) belonging to the clerodane and tetracyclic diterpene types were isolated from the CHCl3 extract of Ballota limbata. The structures of the new compounds 1 and 4–6 (named ballatenolide A and limbatenolides A–C, resp.) were established by their spectral data, and their relative configuration was determined by 2D NMR. Compounds 2 and 3 were identified as known clerodanes. Compound 1 had a unique feature, i.e., an α,β‐unsaturated γ‐lactone moiety at C(4)/C(6), whereas limbatenolides A–C (4–6) belonged to the rare class of tetracyclic diterpenoids, which are known to occur only in the genus Ballota. All of the isolated compounds showed inhibitory potential in a cholinesterase‐inhibition assay.
Oxidative Rearrangement of 1‐Alkylidene‐1,2,3,4‐tetrahydro‐2‐(trichloroacetyl)isoquinolines to 1,5,6,10b‐Tetrahydro‐10b‐(trichloromethyl)‐3H‐oxazolo[4,3‐a]isoquinolin‐3‐ones
Authors: Lenz George R. , Lessor Ralph A. , Rafalko Patrice W. , Ezell Edward F. , Kosarych Zenyk , Meyer Lars , Margaretha Paul
Published: March 2004

On treatment with lead tetraacetate (Pb(OAc)4), the 1‐(alkylidene)‐1,2,3,4‐tetrahydro‐N‐(trichloroacetyl)isoquinolines 2a–2c as well as the tribromoacetyl derivative 4 undergo an oxidative cyclization with concomitant migration of the trihalogenomethyl group to afford the 1,5,6,10b‐tetrahydro‐10b‐(trichloromethyl)‐3H‐oxazolo[4,3‐a]isoquinolin‐3‐ones 3a–3c or the tribromomethyl derivative 6, respectively. These tricycles are also accessible via esterification of 3,4‐dihydro‐1‐(1‐hydroxy‐1‐methylethyl)isoquinoline 8 with either trichloroacetyl chloride or tribromoacetyl bromide, respectively. A plausible mechanistic description for these reactions involves an – unprecedented – ‘intramolecular iminohaloform’ rearrangement.
Solid‐Phase Synthesis of Oligo(triacetylene)s and Oligo(phenylenetriacetylene)s Employing Sonogashira and CadiotChodkiewicz‐Type Cross‐Coupling Reactions
Authors: Utesch Nils F. , Diederich François , Boudon Corinne , Gisselbrecht Jean‐Paul , Gross Maurice
Published: March 2004

We describe the first polymer‐supported synthesis of poly(triacetylene)‐derived monodisperse oligomers, utilizing Pd0‐catalyzed Sonogashira and CadiotChodkiewicz‐type cross‐couplings as the key steps in the construction of the acetylenic scaffolds. For our investigations, Merrifield resin functionalized with a 1‐(4‐iodoaryl)triazene linker was chosen as the polymeric support (R2; Figure and Scheme 3). The linker selection was made based on the results of several model studies in the liquid phase (Schemes 1 and 2). For the solid‐support synthesis of the oligo(phenylene triacetylene)s 7b–7d, a set of only three reactions was required: i) Pd0‐catalyzed Sonogashira cross‐coupling, ii) Me3Sialkyne deprotection by protodesilylation, and iii) cleavage of the linker with liberation of the generated oligomers (Scheme 5). The longest‐wavelength absorption maxima of the oligo(phenylene triacetylene)s 7a–7d shift bathochromically with increasing oligomeric length, from λmax 337 nm (monomer 7a) to 384 nm (tetramer 7d; Table 2). Based on the electronic absorption data, the effective conjugation length (ECL) of the oligo(phenylene triacetylene)s is estimated to involve at least four monomer units and 40 C‐atoms. π‐Electron conjugation in these oligomers is less efficient than in the known oligo(triacetylene)s 14a–14d (Table 2) due to poor transmittance of π‐electron delocalization by the phenyl rings inserted into the oligomeric backbone. Similar conclusions were drawn from the electrochemical properties of the two oligomeric series as determined by cyclic (CV) and rotating‐disk voltammetry (RDV; Table 3). In sharp contrast to 14b–14d, the oligo(phenylene triacetylene)s 7b–7d are strongly fluorescent, with the highest quantum yield ΦF=0.69 measured for trimer 7c (Table 2). Whereas the Sonogashira cross‐coupling on solid support proceeded smoothly, optimal conditions for alkynealkyne cross‐coupling reactions employing Pd0‐catalyzed CadiotChodkiewicz conditions still remain to be developed, despite extensive experimentation (Scheme 7 and Table 1).
Analytical solution to a bias in the TOPMODEL framework balance
Authors: Saulnier G.‐M. , Datin R.
Published: March 2004

The increasing need for distributed hydrological modelling leads to an intense use of spatially distributed predictions of physically based models, such as TOPMODEL as addressed here. The ability of these models to reproduce the internal behaviour of catchments physically is increasingly tested through field experiments (geochemical investigation, distributed measurements network, etc.). This paper will show that, in the case of TOPMODEL, an implicit approximation remains in the classic derivation of the equations that consists in neglecting the surface of saturated areas with respect to the total surface of the catchment. This simplifying, though unnecessary, approximation leads to a systematic underestimation of the catchment water storage deficit and to divergence in the water budget accounting. This may also significantly change the predicted ratio between subsurface and surface water fluxes in the total discharge. An analytical solution is suggested that leads to water balance accounting which is better defined, and more consistent in comparison with field water storage recording. It is expected that this work will ensure more accurate TOPMODEL predictions, consistent with the assumptions of the model. This will then improve the interpretation of comparisons between results of simulation and field experiments. Copyright © 2004 John Wiley & Sons, Ltd.
Seasonal and interannual variations of nitrate and chloride in stream waters related to spatial and temporal patterns of groundwater concentrations in agricultural catchments
Authors: Martin C. , Aquilina L. , Gascuel‐Odoux C. , Molénat J. , Faucheux M. , Ruiz L.
Published: March 2004

Nitrate concentrations in streamwater of agricultural catchments often exhibit interannual variations, which are supposed to result from land‐use changes, as well as seasonal variations mainly explained by the effect of hydrological and biogeochemical cycles. In catchments on impervious bedrock, seasonal variations of nitrate concentrations in streamwater are usually characterized by higher nitrate concentrations in winter than in summer. However, intermediate or inverse cycles with higher concentrations in summer are sometimes observed. An experimental study was carried out to assess the mechanisms that determine the seasonal cycles of streamwater nitrate concentrations in intensive agricultural catchments. Temporal and spatial patterns of groundwater concentrations were investigated in two adjacent catchments located in south‐western Brittany (France), characterized by different seasonal variations of streamwater nitrate concentrations. Wells were drilled across the hillslope at depths ranging from 1·5 to 20 m. Dynamics of the water table were monitored and the groundwater nitrate and chloride concentrations were measured weekly over 2 years. Results highlighted that groundwater was partitioned into downslope domains, where denitrification induced lower nitrate concentrations than into mid‐slope and upslope domains. For one catchment, high subsurface flow with high nitrate concentrations during high water periods and active denitrification during low water periods explained the higher streamwater nitrate concentrations in winter than in summer. For the other catchment, the high contribution of groundwater with high nitrate concentrations smoothed or inverted this trend. Increasing bromide/chloride ratio and nitrate concentrations with depth argued for an effect of past agricultural pressure on this catchment. The relative contribution of flows in time and correlatively the spatial origin of waters, function of the depth and the location on the hillslope, and their chemical characteristics control seasonal cycles of streamwater nitrate concentrations and can influence their interannual trends. Copyright © 2004 John Wiley & Sons, Ltd.
Factors governing the formation and persistence of layers in a subalpine snowpack
Authors: Gustafsson David , Waldner Peter A. , Stähli Manfred
Published: March 2004

The layered structure of a snowpack has a great effect on several important physical processes, such as water movement, reflection of solar radiation or avalanche release. Our aim was to investigate what factors are most important with respect to the formation and persistence of distinct layers in a subalpine environment. We used a physically based numerical one‐dimensional model to simulate the development of a snowpack on a subalpine meadow in central Switzerland during one winter season (1998–99). A thorough model validation was based on extensive measurement data including meteorological and snow physical parameters. The model simulated the snow water equivalent and the depth of the snowpack as well as the energy balance accurately. The observed strong layering of the snowpack, however, was not reproduced satisfactorily. In a sensitivity analysis, we tested different model options and parameter settings significant for the formation of snow layers. The neglection of effects of snow microstructure on the compaction rate, and the current description of the water redistribution inside the snowpack, which disregard capillary barrier effects, preferential flow and lateral water flow, were the major limitations for a more realistic simulation of the snowpack layering. Copyright © 2004 John Wiley & Sons, Ltd.
Tritium hydrology of the Mississippi River basin
Authors: Michel Robert L.
Published: March 2004

In the early 1960s, the US Geological Survey began routinely analysing river water samples for tritium concentrations at locations within the Mississippi River basin. The sites included the main stem of the Mississippi River (at Luling Ferry, Louisiana), and three of its major tributaries, the Ohio River (at Markland Dam, Kentucky), the upper Missouri River (at Nebraska City, Nebraska) and the Arkansas River (near Van Buren, Arkansas). The measurements cover the period during the peak of the bomb‐produced tritium transient when tritium concentrations in precipitation rose above natural levels by two to three orders of magnitude. Using measurements of tritium concentrations in precipitation, a tritium input function was established for the river basins above the Ohio River, Missouri River and Arkansas River sampling locations. Owing to the extent of the basin above the Luling Ferry site, no input function was developed for that location. The input functions for the Ohio and Missouri Rivers were then used in a two‐component mixing model to estimate residence times of water within these two basins. (The Arkansas River was not modelled because of extremely large yearly variations in flow during the peak of the tritium transient.) The two components used were: (i) recent precipitation (prompt outflow) and (ii) waters derived from the long‐term groundwater reservoir of the basin. The tritium concentration of the second component is a function of the atmospheric input and the residence times of the groundwaters within the basin. Using yearly time periods, the parameters of the model were varied until a best fit was obtained between modelled and measured tritium data. The results from the model indicate that about 40% of the flow in the Ohio River was from prompt outflow, as compared with 10% for the Missouri River. Mean residence times of 10 years were calculated for the groundwater component of the Ohio River versus 4 years for the Missouri River. The mass flux of tritium through the Mississippi Basin and its tributaries was calculated during the years that tritium measurements were made. The cumulative fluxes, calculated in grams of 3H were: (i) 160 g for the Ohio (1961–1986), (ii) 98 g for the upper Missouri (1963–1997), (iii) 30 g for the Arkansas (1961–1997) and (iv) 780 g for the Mississippi (1961–1997). Copyright © 2004 John Wiley & Sons, Ltd.