bluuebunny/crossref_metadata_2025_split huggingface dataset:
The 5‐HT2A receptor is widely distributed in the rat spinal cord and mainly localized at the plasma membrane of postsynaptic neurons
Authors: Doly Stéphane , Madeira Alexandra , Fischer Jacqueline , Brisorgueil Marie‐Jeanne , Daval Genevieve , Bernard Rozenn , Vergé Daniel , Conrath Marie 
Published: March 2004

AbstractSerotonin (5‐HT) plays a major role at the spinal level by modulating most spinal functions through several receptor subtypes including the 5‐HT2A receptor. To gain further insight into the cellular role of this receptor, we performed an immunocytochemical study of 5‐HT2A receptors in the rat spinal cord, at light and electron microscope levels. The results showed that 5‐HT2A receptors were widely distributed in the spinal cord at all segmental levels. Immunolabeling was particularly dense in lamina IX and in the dorsal horn lamina IIi. Immunoreactive cell bodies were numerous in lamina IX, where many but not all motoneurons were labeled, as shown by double labeling with choline acetyltransferase antibodies. Stained cell bodies were also observed in the gray matter. The study at the ultrastructural level focused on the lumbar dorsal horn (laminae I–II) and ventral horn (lamina IX). At both levels, 5‐HT2A immunoreactivity was mainly postsynaptic on dendrites and cell bodies. However, a little presynaptic labeling was also observed in axon and axon terminals, some of them containing large granular vesicles attesting to their peptidergic nature. The main result of our study was the “nonsynaptic” plasma membrane localization of 5‐HT2A receptors covering a large surface of cell bodies and dendrites, suggesting a paracrine form of action of serotonin. These observations are consistent with a double role (pre‐ and postsynaptic) for serotonin on these receptors on various cellular targets. J. Comp. Neurol. 472:496–511, 2004. © 2004 Wiley‐Liss, Inc.
Diversity of contralateral commissural projections in the embryonic rodent spinal cord
Authors: Kadison Stephanie Rebecca , Kaprielian Zaven 
Published: March 2004

AbstractIn vertebrate embryos, the axons of spinal commissural neurons grow toward and across the floor plate, a specialized structure located at the ventral midline. Although the initial segment of this trajectory has been intensively studied, relatively little is known about commissural axon pathfinding on the contralateral side of the floor plate in higher vertebrates. We recently demonstrated that many embryonic mouse and chick spinal commissural axons follow a complex trajectory once they cross the ventral midline. Here we use focal applications of 1,1′‐dioctadecyl‐3,3,3′,3′ tetramethylindocarbocyanine perchlorate (DiI) to identify four different contralateral commissural trajectories, two of which have not previously been described in the embryonic rodent spinal cord. Intermediate longitudinal commissural (ILC) axons travel away from the floor plate along an arcuate trajectory into intermediate regions of the spinal cord. In contrast, medial longitudinal commissural (MLC) axons grow alongside the floor plate, projecting primarily in the rostral direction. Bifurcating longitudinal commissural (BLC) axons branch into rostrally and caudally directed projections. Forked transverse commissural (FTC) axons either execute two orthogonal turns before crossing the floor plate or extend directly across the floor plate. We also show a variation in the relative frequencies of individual contralateral commissural projections along the dorsoventral and anteroposterior axes of the spinal cord. In addition, using a novel culture system, we demonstrate that commissural axons elaborate ILC‐, MLC‐, BLC‐, and FTC‐like trajectories in vitro. These results provide a basis for examining the mechanisms that regulate commissural axon pathfinding on the contralateral side of the floor plate in the embryonic rodent spinal cord. J. Comp. Neurol. 472:411–422, 2004. © 2004 Wiley‐Liss, Inc.
Schwarz alternating method based on natural boundary reduction for time‐dependent problems on unbounded domains
Authors: Du Qikui , Yu Dehao 
Published: March 2004

AbstractBy using the natural boundary reduction an overlapping domain decomposition method is designed to solve some exterior two‐dimensional time‐dependent parabolic problems. The governing equation is first discretized in time, leading to a sequence of boundary value problems with respect to time step in an unbounded domain. Then artificial boundaries are introduced. For each time level, an overlapping domain decomposition method, which is based on the natural boundary reduction, is constructed to solve the exterior elliptic boundary value problem on a two‐dimensional domain. It is shown that the algorithm is equivalent to Schwarz alternating method. The convergence of this algorithm is given. The contraction factor for the exterior circular domain is also discussed. In the end of this paper, some numerical examples are presented, which illustrate the feasibility and the effectiveness of the proposed methods in this paper. Copyright © 2004 John Wiley & Sons, Ltd.
A third‐order accurate time scheme for variably saturated groundwater flow modelling
Authors: Guarracino Luis , Quintana Fernando 
Published: March 2004

AbstractA numerical algorithm to simulate water flow in variably saturated non‐deformable porous media is presented. The algorithm is based on the numerical approximation of Richards' non‐linear equation. This equation is discretized in time by using a third‐order Crank–Nicholson scheme based on Richardson extrapolation. The proposed time scheme is third‐order accurate and presents advantages over standard time discretizations of Richards' equation. A Galerkin finite element procedure is employed for spatial approximation. Numerical tests showing the performance and numerical properties of the proposed algorithm are presented. Copyright © 2004 John Wiley & Sons, Ltd.
A non‐linear co‐ordinate transformation for accurate numerical evaluation of weakly singular integrals
Authors: Yun Beong In 
Published: March 2004

AbstractIn order to obtain accurate numerical evaluation of weakly singular integrals, we propose a new non‐linear co‐ordinate transformation of the sigmoidal type. The asymptotic behaviour of the present transformation near a singular point is governed by an additional parameter b≠0. Moreover, an analytical form of its inverse is derived, which is available for the case of interior‐point singularity. In the result the presented transformation can improve asymptotic truncation errors of the Gauss–Legendre quadrature rule for weakly singular integrals.By comparing the present transformation with existing sigmoidal transformations in numerical examples, we show that the former with a proper value of b can result in more accurate evaluation than the others. Copyright © 2004 John Wiley & Sons, Ltd.
Reviewing the application of SEA to sectoral plans in Italy. The case of the mobility plan of an alpine region
Authors: Diamantini Corrado , Geneletti Davide 
Published: March 2004

AbstractWithin the Italian context, the application of SEA is particularly advanced in the Autonomous Province of Trento (APT). The APT recently approved a plan on sustainable development in which the selected sustainability indicators were explicitly considered as the reference for future SEAs. Subsequently, guidelines to carry out the environmental report, i.e. the core document of SEA, were issued and experimentally applied to several sectoral plans. This paper critically reviews the experience of the APT, by focusing on the positive elements and shortcomings that affect the guidelines and their application. The environmental report of the APT's Mobility Plan was selected as a case study. This plan has a high strategic relevance because it deals with several critical issues, such as trans‐alpine traffic. The paper concludes that the approach was set out in an interesting and innovative way, but its application is affected by some limitations, such as the lack of indicator‐based analyses. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Requirements of the SEA Directive and the German Federal Transport Infrastructure Plan
Authors: Wende Wolfgang , Hanusch Marie , Gassner Erich , Guennewig Dieter , Koeppel Johann , Lambrecht Heiner , Langenheld Alexandra , Peters Wolfgang , Roethke‐Habeck Petra 
Published: March 2004

AbstractThis paper presents some preliminary results of a research project started in May 2002 on the German transportation planning system, commissioned by the Federal Environmental Agency. The main aim of this project is to find ways to integrate formal strategic environmental assessment (SEA) and to identify technical and methodological opportunities for implementing the SEA Directive. It reveals that whilst environmental aspects are already taken into account to a reasonable extent, certain amendments are needed in order to fully meet the requirements of the SEA Directive. Furthermore, the paper calls for a new type of ‘Federal Transport Development Plan’. This should focus on an assessment of strategic alternatives as the basis for the integration of individual projects. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Integrating Strategic Environmental Assessment into community development plans — a case study from Austria
Authors: Stoeglehner Gernot 
Published: March 2004

Abstract‘Community development plans’ contain the objectives and measures for the spatial development of a municipality. Most likely these plans will be within the scope of the SEA Directive. To determine how they perform in terms of the SEA Directive, an ex post survey of an already completed planning process is used. For this purpose two tools are developed by the author: an ‘idealized planning scheme including SEA’ and a ‘natural goods–planning content matrix’. These tools are used to compare the procedures and contents of the planning process of the case study with the SEA demands and to determine the requested amendments for the planning processes. The result of this examination is that the practice of community development planning already largely complies with the SEA Directive. In some phases of the planning process more precise regulations will be needed that have a high potential to contribute to an elevated quality of spatial planning concerning environmental aspects. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Bis‐ and Tris‐DNA Intercalating Porphyrins Designed to Target the Major Groove: Synthesis of Acridylbis‐arginyl‐porphyrins, Molecular Modelling of Their DNA Complexes, and Experimental Tests
Authors: Far Samia , Kossanyi Alain , Verchère‐Béaur Catherine , Gresh Nohad , Taillandier Eliane , Perrée‐Fauvet Martine 
Published: March 2004

AbstractIn order to increase the DNA binding affinity of a bis‐arginyl‐porphyrin which has been previously shown to bind preferentially in the major groove of the d(GGCGCC)2 sequence (Mohammadi et al., Biochemistry 1998, 37, 9165), we have synthesized bis‐ and tris‐intercalating derivatives in which one or both arginyl arms are connected through a flexible chain to an acridine ring. We report here the synthesis of these two molecules along with the molecular modelling of their complexes with a GC‐rich oligonucleotide encompassing the central d(GGCGCC)2 hexamer. The modelling computations showed that when the porphyrin was intercalated into the central d(CpG)2 site with both arginyl side‐chains bonded to the guanines flanking the intercalation site, the acridine ring(s) could intercalate immediately upstream from the central hexamer, but at the cost of substantial DNA conformational energy. A significant preference for major‐groove binding over minor‐groove binding was found. The results of circular dichroism studies and topoisomerase I‐unwinding experiments supported the bis‐ and tris‐intercalation of these derivatives. The bis‐acridyl derivative provided, as expected, greater stabilization against thermal denaturation than the mono‐acridyl and the parent bis‐arginyl‐porphyrin compounds. Based on the modelling results, the structures of derivatives can be tailored to facilitate tris‐intercalation in rigid GC‐rich sequences, and thereby enhance the selective targeting of GC base pairs by the arginyl side‐chains, by lengthening the porphyrin‐acridine connectors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Chromophoric Azo Reagents for Amino Acid and Peptide Labelling
Authors: Fraga Susana M. B. , Gonçalves Maria S. T. , Moura João C. V. P. , Rani Kavitha 
Published: March 2004

AbstractFour carboxylic azo dyes, with spectroscopic absorption peaks ranging from 400 to 500 nm, are presented as new markers for amino acid and peptide labelling at their N‐terminus. Labelling can also be performed at side‐chain residues as is exemplified with lysine and serine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of Tetrastilbenylmethanes by Wittig−Horner Reactions
Authors: Kim Soungkyoo , Seus Peter , Meier Herbert 
Published: March 2004

AbstractThe all‐(E)‐configured tetrastilbenylmethanes 3a−e and 5a,b can be obtained by fourfold Wittig−Horner reactions. The tetrahedral arrangement of these compounds guarantees independent stilbenoid chromophores with a high chromophore density. Apart from (E)/(Z) isomerization reactions, irradiation leads to a three‐dimensional network with isolated unchanged stilbene units. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Formal Desymmetrization of the Diastereotopic Chains in Gemini Calcitriol Derivatives with Two Different Side Chains at C‐20
Authors: Maehr Hubert , Uskokovic Milan R. 
Published: March 2004

AbstractDerivatives of calcitriol with two equal side chains emanating at C‐20, also known as gemini, have emerged as interesting compounds, either as instruments for assessing the steric requirements of the vitamin D receptor or as drug candidates. We now describe the syntheses of gemini analogs where the two side chains differ from each other. While retaining the 2‐hydroxy‐2‐methylpentyl moiety, common to both calcitriol and gemini, as one chain, we replaced the other with a 1,1,1‐trifluoro‐2‐hydroxy‐2‐(trifluoromethyl)‐3‐pentynyl group. The features comprising this chain modification are commonly regarded to improve toxicity profiles and drug performance. The resulting epimeric pairs with a new stereogenic center at C‐20 were resolved and the absolute configurations assigned. The side‐chain desymmetrization protocols described herein serve as a basis for additional synthesis activity in this area. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of Calystegine B2, B3, and B4 Analogues: Mapping the Structure‐Glycosidase Inhibitory Activity Relationships in the 1‐Deoxy‐6‐oxacalystegine Series
Authors: García‐Moreno M. Isabel , Ortiz Mellet Carmen , García Fernández José M. 
Published: March 2004

AbstractA practical synthesis of ring‐modified calystegine analogues with a 6‐oxa‐nor‐tropane structure has been developed. The methodology relies on the ability of the masked carbonyl group of hexose precursors to act as the electrophilic target for the nitrogen atom of pseudoamide (urea or thiourea) groups located at the C‐5 position through the open‐chain aldehyde form. The resulting piperidine species undergoes spontaneous intramolecular glycosylation reaction involving 6‐OH provided that the resulting bicyclic aminoacetal fulfils the anomeric effect. The hydroxylation profile of the imino sugar glycomimetics thus obtained can be modified by judicious choice of the monosaccharide template. The validity of the strategy has been demonstrated by the preparation of N‐thiocarbamoyl and N‐carbamoyl derivatives of 1‐deoxy‐6‐oxa‐(+)‐calystegine B2, (−)‐B4, (+)‐B3, and (−)‐B2 from L‐ido, L‐gulo, L‐altro, and D‐ido precursors. The requested thioureas and ureas were obtained from 5‐amino‐ or 5‐azido‐5‐deoxyhexofuranose derivatives by a coupling reaction with isothiocyanates or a tandem Staudinger−aza‐Wittig‐type reaction with triphenylphosphane and an isothiocyanate followed by addition of water to the resulting carbodiimide, respectively. Attempts to prepare analogues with the unnatural 3‐epi‐(+)‐calystegine B2 hydroxylation profile from L‐talofuranose (thio)ureas by this methodology led, however, to equilibrium mixtures of the furanose anomers, with only traces of the nor‐tropane form. Evaluation of the inhibitory activity of the whole series of calystegine analogues against several glycosidases indicated that the main structural requirements for strong and specific inhibition of bovine liver β‐glucosidase/β‐galactosidase are the all‐equatorial orientation of the triol system at the piperidine ring, the presence of a lipophilic substituent at the nitrogen atom and the location of the intramolecular aminoacetal oxygen atom at the 6‐position of the nor‐tropane core. On the basis of these data, a structural analogy of 6‐oxa‐(+)‐calystegine B2 derivatives with the natural calystegine C1 has been established and a 1‐azasugar inhibition mode is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Reactions of 1,3‐Diaryl‐2‐chloropropane‐1,3‐diones with Nucleophiles − Cyanide‐Induced Retro‐Claisen−Claisen Condensation
Authors: Roshchupkina Galina I. , Gatilov Yury V. , Rybalova Tatyana V. , Reznikov Vladimir A. 
Published: March 2004

AbstractTreatment of some 1,3‐diaryl‐2‐chloropropane‐1,3‐diones, acyclic chloro‐substituted enaminones and β‐oxo esters with nucleophiles was shown to proceed easily with the formation, at least in the first stage, of formal nucleophilic substitution products. Treatment of enaminones and β‐oxo esters with azide and cyanide ions proceeds with the preservation of the skeleton, whereas chloro‐substituted diaroylmethanes undergo retro‐Claisen−Claisen condensation reactions in the course of the reaction with cyanide. Dibenzoylchloromethane reacts with azide and cyanide ions with fragmentation of the molecule and subsequent reassembly, resulting in benzoylated benzaldehyde cyanohydrin and a 1,3‐oxathiol derivative, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Novel Cyclic 1,2‐Diacetals Derived from (2R,3R)‐(+)‐Tartaric Acid: Synthesis and Application as N,O Ligands for the Enantioselective Alkylation of Benzaldehyde by Diethylzinc
Authors: Barros M. Teresa , Maycock Christopher D. , Phillips Ana Maria Faísca 
Published: March 2004

AbstractA chiral cyclic 1,2‐diacetal derived from tartaric acid was used as the basic structural unit for novel ligands. Monooxazoline carbinols in which the degree of substitution of the alcohol and the nature of the stereocentre in the oxazoline ring were varied were synthesized in moderate to good yields. The influence of these structural factors on asymmetric induction was examined in the enantioselective addition of diethylzinc to benzaldehyde. Up to 60% ee was observed with a secondary or a tertiary alcohol as the metal‐chelating group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electrochromic Application of an Enediyne Scaffolding as a Redox‐Active Chromophore − Synthesis and Redox Behavior of 9,10‐Bis[3‐(6‐azulenyl)‐1‐(6‐azulenylethynyl)‐2‐propynylidene]‐9,10‐dihydroanthracenes
Authors: Ito Shunji , Inabe Haruki , Morita Noboru , Tajiri Akio 
Published: March 2004

AbstractA bis(enediyne) system utilizing anthraquinodimethane as a platform for a redox‐active substructure that bears azulenes as π‐electron‐accepting groups at the periphery has been prepared by a simple one‐pot reaction involving repeated Pd‐catalyzed alkynylation of 6‐bromoazulenes with the bis(enediyne). The novel bis(enediyne)s exhibited two, one‐step two‐electron redox properties under electrochemical reduction conditions together with a significant color change owing to the generation of a closed‐shell cyanine‐type substructure by the two‐electron reduction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Asymmetric Synthesis of 2‐Amino‐1,3‐diols and D‐erythro‐Sphinganine
Authors: Enders Dieter , Müller‐Hüwen Anke 
Published: March 2004

AbstractThe asymmetric synthesis of protected 2‐amino‐1,3‐diols (S,R)‐5 starting from 2,2‐dimethyl‐1,3‐dioxan‐5‐one is described. The stereogenic centres are generated by α‐alkylation using the SAMP/RAMP hydrazone methodology and diastereoselective reduction of the ketones (S)‐2 with L‐selectride. The resulting alcohols (S,S)‐3 are converted into the amines (S,R)‐4 by nucleophilic substitution with sodium azide and subsequent reduction with lithium aluminium hydride. The products are obtained in high diastereomeric and enantiomeric excesses (de ⩾ 96%, ee = 90−94%). By employing this methodology, the ammonium salt of D‐erythro‐sphinganine (R,S)‐11 was synthesised starting from RAMP‐hydrazone (R)‐1 in 47% overall yield and with excellent diastereomeric and enantiomeric excess (de, ee ⩾ 96%). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Enantioselective Lutidine‐Tetrahydrobenzoxanthene Receptors for Carboxylic Acids
Authors: Oliva Ana I. , Simón Luis , Muñiz Francisco M. , Sanz Francisca , Morán Joaquín R. 
Published: March 2004

AbstractReceptors based on cis‐ and trans‐tetrahydrobenzoxanthene skeletons combined with benzoxazoles and pyridines have shown enantioselective binding to sulfonylamino acids. The keto‐enol tautomeric equilibrium of the receptors shifts towards the keto form upon complexation. X‐ray analysis of the trans receptor complex with L‐leucine triflamide (H) reveals an unexpected structure, in which the basic pyridine nitrogen accepts the strong H‐bond of the guest, while the benzoxazole acts as a counterpart for the sulfonamide group. l‐Carbamoyllactic acid (C) is a suitable guest for the resolution of the racemic mixture of the trans receptor, which can be performed by impregnating TLC plates with the guest. Extraction of racemic carbamoyllactic acid (C) and its ammonium salt from a chloroform/water system with the trans receptor 4 provided a procedure for the resolution of the guest. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Radical Reactions Using Decacarbonyldimanganese under Biphasic Conditions
Authors: Huther Nathalie , McGrail P. Terry , Parsons Andrew F. 
Published: March 2004

AbstractRadical reactions of alkyl halides, initiated by photolysis in the presence of decacarbonyldimanganese, can be performed in biphasic media. Reactions in the presence of aqueous sodium hydroxide together with a phase‐transfer catalyst result in the efficient removal of manganese halide by‐products and also lead to the regeneration of decacarbonyldimanganese. A range of efficient radical couplings, cyclisations and intermolecular addition reactions were performed under these conditions. This included the development of a new tandem radical addition−ionic cyclisation sequence that was employed in a short approach to (±)‐coronamic acid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Spectroelectrochemical Study on the Electrooxidation in Aqueous Medium of some 1,4‐Dihydropyridines: Effects of Substitution in 1‐Position and 4‐Position
Authors: López‐Alarcón C. , Squella J. A. , Miranda‐Wilson D. , Núñez‐Vergara Luis J. 
Published: March 2004

AbstractSpectroelectrochemical and HPLC characterization of the electrochemical oxidation in aqueous medium of a series of six N‐1 and C‐4 substituted 1,4‐dihydropyridines is presented. Based on the analysis of spectra obtained by in situ spectroscopic measurements it was possible to detect the generation of final oxidation products, which resulted in differences depending of the nature of the substitution on the nitrogen in the dihydropyridine ring. Controlled potential electrolysis (CPE) in aqueous medium was followed by the HPLC technique using EC and PDA detectors. This latter resulted adequately to follow the parent 1,4‐DHP derivatives and their respective oxidation products. Electrochemical oxidation of parent N‐H substituted 1,4‐dihydropyridines generated the corresponding neutral pyridine derivative as final oxidation product. However, the N‐ethyl substituted 1,4‐dihydropyridine derivatives gave rise to the pyridinium salt derivatives.