bluuebunny/crossref_metadata_2025 huggingface dataset:
Successful rotational atherectomy in the setting of extensive coronary dissection: A case of failed balloon angioplasty in a nondilatable calcified lesion complicated by balloon rupture and extensive dissection
Authors: Pedersen Wesley R. , Goldenberg Irvin F. , Johnson Randall K. , Mooney Michael R.
Published: June 2003

We describe a case of rotational atherectomy (RA) used in the setting of extensive coronary dissection. Unsuccessful predilitation of a heavily calcified proximal LAD stenosis resulted in balloon rupture, which produced occlusive dissection extending into the mid LAD. Limited options for this patient required that we perform RA to permit stent delivery and deployment and avoid anterior myocardial infarction. A brief discussion of reasons for balloon angioplasty failure and the potential role for subsequent RA is given. Predictors for coronary perforation when performing RA are reviewed. Our rationale and strategy to avoid the increased risk of perforation with RA in this contraindicated setting of extensive dissection is given. Cathet Cardiovasc Intervent 2003;59:329–332. © 2003 Wiley‐Liss, Inc.
Upendra Kaul, Ripen K. Gupta, Kottaram K. Haridas, Saligrama S. Ramesh, Kamal K. Sethi, Balbir Singh, Rajiv Agarwal, Ram D. Yadave, Tapan Ghose, Rakesh R. Sapra, Rajiv Bajaj, Madhukar Shahi, Ajit Bhagwat, Pramod Kumar, Omen P. Mathews, Pratik K. Soni. Platelet glycoprotein IIb/IIIa inhibition using eptifibatide with primary coronary stenting for acute myocardial infarction: A 30‐day follow‐up study. Cathet Cardiovasc Intervent 2002;57(4):497–503
Authors: Kaul Upendra
Published: June 2003

The original article to which this Erratum refers was published in Cathet Cardiovasc Intervent (2002)57:497–503
Organization of postsynaptic density proteins and glutamate receptors in axodendritic and dendrodendritic synapses of the rat olfactory bulb
Authors: Sassoé‐Pognetto Marco , Utvik Jo K. , Camoletto Paola , Watanabe Masahiko , Stephenson F. Anne , Bredt David S. , Ottersen Ole P.
Published: June 2003

Glutamate neurotransmission in the olfactory bulb involves both axodendritic synapses and dendrodendritic reciprocal synapses and possibly also extrasynaptic receptors. By using a sensitive immunogold procedure, we have investigated the organization of two synaptic scaffolding molecules, PSD‐95 and PSD‐93, as well as N‐methyl‐D‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐proprionic acid (AMPA) receptors, at these heterogeneous glutamate signaling sites. Immunolabeling for PSD‐95 and PSD‐93 was present in all major types of putative glutamatergic synapse, suggesting that these proteins are essential components of the synaptic signaling apparatus. The linear density and the subsynaptic distribution of PSD‐95/PSD‐93 gold particles did not differ significantly between axodendritic and dendrodendritic synapses. Antibodies recognizing NMDA and AMPA receptor subunits also labeled asymmetric synapses throughout the olfactory bulb. Immunolabeling for the AMPA receptor subunits GluR2/3 was similar in all types of synapse. In contrast, immunogold signals for the NR1 subunit of NMDA receptors varied significantly among different synapse populations, with olfactory nerve synapses in the glomerular layer showing the lowest labeling intensity. Although the lateral dendrites of mitral and tufted cells have been reported to respond to glutamate, they did not display significant plasma membrane labeling for the NR1 subunit or for PSD‐95, suggesting that the physiological effects of glutamate at these sites are mediated by NMDA autoreceptors that are not clustered and occur only at a low density on the dendritic surface. Our quantitative analysis of olfactory bulb synapses indicates that the density of NMDA receptors is not determined by the complement of PSD‐95/PSD‐93. The latter molecules appear to be expressed in an all‐or‐none fashion and may form a standard lattice common to different types of glutamatergic synapse. J. Comp. Neurol. 463:237–248, 2003. © 2003 Wiley‐Liss, Inc.
Connections of the retrosplenial granular b cortex in the rat
Authors: Van Groen Thomas , Wyss J. Michael
Published: June 2003

Although the retrosplenial granular b cortex (Rgb) is situated in a critical position between the hippocampal formation and the neocortex, surprisingly few studies have examined its connections carefully. The present experiments use both anterograde and retrograde tracing techniques to characterize the connections of Rgb. The main cortical projections from Rgb are to the caudal part of the anterior cingulate cortex, area 18b, retrosplenial granular a cortex (Rga), and postsubiculum, and less dense terminal fields are present in the prelimbic and caudal occipital cortices. The major subcortical projections are to the anterior thalamic nuclei and the rostral pontine nuclei, and very small terminal fields are present in the caudal dorsomedial part of the striatum, the reuniens and reticular nuclei of the thalamus, and the mammillary bodies. Contralaterally, Rgb primarily projects to itself, i.e., homotypically, and more sparsely projects to Rga and postsubiculum. In general, the axons from Rgb terminate ipsilaterally in cortical layers I and III–V and contralaterally in layer V, with a smaller number of terminals in layers I and VI. Thalamic projections from Rgb target the anteroventral and laterodorsal nuclei of the thalamus, with only a few axons terminating in the anterodorsal nucleus, the reticular nucleus, and the nucleus reuniens of the thalamus. Rgb is innervated by the anterior cingulate cortex, precentral agranular cortex, cortical area 18b, dorsal subiculum, and postsubiculum. Subcortical projections to Rgb originate mainly in the claustrum, the horizontal limb of the diagonal band of Broca, and the anterior thalamic nuclei. These data demonstrate that, in the rat, Rgb is a major nodal point for the integration and subsequent distribution of information to and from the hippocampal formation, the midline limbic and visual cortices, and the thalamus. Thus, similarly to the entorhinal cortex, Rgb in the rat is a prominent gateway for information exchange between the hippocampal formation and other limbic areas of the brain. J. Comp. Neurol. 463:249–263, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of high affinity choline transporter immunoreactivity in the primate central nervous system
Authors: Kus Laura , Borys Ewa , Ping Chu Ya , Ferguson Shawn M. , Blakely Randy D. , Emborg Marina E. , Kordower Jeffrey H. , Levey Allan I. , Mufson Elliott J.
Published: June 2003

A mouse monoclonal antibody (clone 62‐2E8) raised against a human recombinant high‐affinity choline transporter (CHT)‐glutathione‐S‐transferase fusion protein was used to determine the distribution of immunoreactive profiles containing this protein in the monkey central nervous system (CNS). Within the monkey telencephalon, CHT‐immunoreactive perikarya were found in the striatum, nucleus accumbens, medial septum, vertical and horizontal limb nuclei of the diagonal band, nucleus basalis complex, and the bed nucleus of the stria terminalis. Dense fiber staining was observed within the islands of Calleja, olfactory tubercle, hippocampal complex, amygdala; moderate to light fiber staining was seen in iso‐ and limbic cortices. CHT‐containing fibers were also present in sensory and limbic thalamic nuclei, preoptic and hypothalamic areas, and the floccular lobe of the cerebellum. In the brainstem, CHT‐immunoreactive profiles were observed in the pedunculopontine and dorsolateral tegmental nuclei, the Edinger‐Westphal, oculomotor, trochlear, trigeminal, abducens, facial, ambiguus, dorsal vagal motor, and hypoglossal nuclei. In the spinal cord, CHT‐immunoreactive ventral horn motoneurons were seen in close apposition to intensely immunoreactive C‐terminals at the level of the cervical spinal cord. CHT immunostaining revealed a similar distribution of labeled profiles in the aged human brain and spinal cord. Dual fluorescent confocal microscopy revealed that the majority of CHT immunoreactive neurons contained the specific cholinergic marker, choline acetyltransferase, at all levels of the monkey CNS. The present observations indicate that the present CHT antibody labels cholinergic structures within the primate CNS and provides an additional marker for the investigation of cholinergic neuronal function in aging and disease. J. Comp. Neurol. 463:341–357, 2003. © 2003 Wiley‐Liss, Inc.
Missplicing resulting from a short deletion in the reelin gene causes reeler‐like neuronal disorders in the mutant shaking rat Kawasaki
Authors: Kikkawa Satoshi , Yamamoto Tatsuro , Misaki Kazuyo , Ikeda Yayoi , Okado Haruo , Ogawa Masaharu , Woodhams Peter L. , Terashima Toshio
Published: June 2003

The shaking rat Kawasaki (SRK) is an autosomal recessive mutant that exhibits reeler‐like abnormal locomotor behaviors. The murine reeler mutants arise from several mutations in the specific gene called reelin, which result in defects of Reelin expression or secretion in the cerebral cortex and other regions of CNS. To address the issue of whether the SRK mutation also arises from a mutation in reelin, we analyzed the reelin gene in SRK. Northern analysis of reelin mRNA from normal rats showed that rat reelin was expressed as a ∼12‐kb transcript in both the cerebrum and the cerebellum, whereas reelin expression was markedly reduced in the SRK brains. In situ hybridization analysis showed that reelin mRNA in the SRK brains was expressed in Cajal‐Retzius cells in the marginal zone of the cerebral cortex and outer granular cells in the cerebellar cortex in similar manners to normal controls, but its expression was considerably reduced. On Western blotting and immunohistochemical analyses using antibodies specific for the Reelin protein, no immunoproduct was recognized in the cerebral and cerebellar cortices. From the cDNA sequences, we found a 64‐base heterologous sequence in SRK reelin, which contains a termination codon in the reading frame. Furthermore, genomic DNA analysis revealed that a 10‐base deletion, which contains a predicted splice donor site, occurred in the SRK genomic reelin gene, resulting in “read through” into the following intron in SRK. Thus, the SRK mutation is another type of mutation that lacks expression of the functional Reelin protein and, therefore, causes the reeler phenotype. J. Comp. Neurol. 463:303–315, 2003. © 2003 Wiley‐Liss, Inc.
Lazy eyes zebrafish mutation affects Müller glial cells, compromising photoreceptor function and causing partial blindness
Authors: Kainz Pamela M. , Adolph Alan R. , Wong Kwoon Y. , Dowling John E.
Published: June 2003

A behavioral assay based on the optokinetic reflex was used to screen chemically mutagenized zebrafish larvae for deficits in visual function. A homozygous recessive mutation, lazy eyes (lze), was isolated based on the observation that 5‐day postfertilization (dpf) mutants displayed weaker and less frequent eye movements than wild‐type fish in response to moving stripes. Electroretinographic (ERG) recordings revealed that mutants had severely reduced a‐ and b‐wave amplitudes relative to wild‐type fish, indicating outer retinal dysfunction. Retinal lamination and cellular differentiation were normal in the lze retina; however, mutant photoreceptor cells had small outer segments and pyknotic nuclei were occasionally observed in the outer retina and the marginal zone of lze. Cone, rod, amacrine, bipolar, and Müller cell marker analyses indicated that the typical lze retina contained fewer rod photoreceptors and fewer Müller cells than wild‐type fish at 5 dpf. At 3 dpf, however, mutant retinas had normal numbers of rod photoreceptors and Müller cells, suggesting that the initial differentiation of these cell types occurred normally. Rod photoreceptor histology was normal at this early stage, but Müller cells were often hypertrophied, suggesting that they were unhealthy. Constant light rearing of mutant animals accelerated the Müller cell degeneration, severely worsened the visual deficit, but had no obvious affect on the photoreceptors. When ERG responses and Müller cell degeneration from the same mutant animals were analyzed, the extent of the Müller cell loss matched closely the degree to which ERG responses were reduced. In summary, the lze gene appears to be required for Müller cell viability and normal visual function. The lze mutant may be a model for the study of the involvement of Müller cells in photoreceptor development and function. J. Comp. Neurol. 463:265–280, 2003. © 2003 Wiley‐Liss, Inc.
Phase‐Selective CVD of Chromium Oxides from Chromyl Chloride
Authors: Cho Y.‐N. , DeSisto W.J.
Published: June 2003

Phase selective chromium oxide films are deposited from chromyl chloride by CVD in the temperature range 320–380 °C. Phase selectivity is found to be driven, in part, by a templating effect of the substrate. Thin films of metastable CrO2 in (100), (001), and (110) orientations have been stabilized, respectively, by (100), (001), and (110) TiO2 single crystal substrates. In contrast, thin oriented films of the more stable Cr2O3 in (006) orientation are formed when depositing on (0001) Al2O3 single crystals over the same deposition temperature range. This phase selectivity appears to be unique to the chromyl chloride precursor.
Nanocomposite Si/Diamond Layers: Room Temperature Visible‐Light Emitting Systems
Authors: Terranova M.L. , Sessa V. , Botti S. , Rossi M. , Motsnyi F.V. , Konchits A.A. , Lytvyn P.M. , Yukhymchuk V.O.
Published: June 2003

Visible‐light emitting nanocomposite Si/diamond polycrystalline layers, produced by means of a hybrid CVD/powder‐flowing technique, have been investigated by atomic force microscopy (AFM), reflection high energy electron diffraction (RHEED), Raman spectroscopy, photoluminescence (PL), and electron spin resonance (ESR). The room temperature emission of the layers at 1.7 eV and 2.0–2.4 eV is dominated by the optical properties of the inserted Si nanoparticles (mean diameter 3.3 ± 0.5 nm). The density of the ESR active centers is N = (4 ± 2) × 1019 cm–3 with g = 2.0025 (T = 300 K). A study of the temperature‐dependent changes in the nature and localization of paramagnetic centers has been carried out by comparing the ESR signals taken at 300 K, 30 K, and 4.2 K. The ESR results suggest that the active centers originate from the dangling bonds induced in sp3‐coordinated C atoms by insertion of the Si nanoparticles. The g‐factor anisotropy, detected at 4.2 K, is consistent with the peculiarities of dipole–dipole interactions in structures with low dimensionality.
Formation of Nano SiC Particles by Laser‐Assisted CVD
Authors: Kamlag Y. , Goossens A. , Colbeck I. , Schoonman J.
Published: June 2003

Nanocrystals of cubic silicon carbide (SiC) are formed using laser‐assisted gas‐phase synthesis. A CO2 laser beam is mechanically chopped to obtain pulsed infrared (IR) excitation. Silane (SiH4) and acetylene (C2H2) have been used as precursors. The SiC particles formed adopt the zinc blende crystal structure (β‐phase) with an average primary particle size of about 12 nm. Higher chopping frequencies yield smaller crystals. Oxidation and subsequent etching with HF removes the oxide shell, leading to further reduction of the particle size to 4 nm.
Deposition of Conductive Ru and RuO2 Thin Films Employing a Pyrazolate Complex [Ru(CO)3(3,5‐(CF3)2‐pz)]2 as the CVD Source Reagent
Authors: Song Y.‐H. , Chen Y.‐L. , Chi Y. , Liu C.‐S. , Ching W.‐L. , Kai J.‐J. , Chen R.‐S. , Huang Y.‐S. , Carty A.J.
Published: June 2003

The reaction of Ru3(CO)12 with three equivalent of 3,5‐bis(trifluoromethyl) pyrazole [(3,5‐(CF3)2‐pz)H] at 180 °C produces the double pyrazolate‐bridged ruthenium complex [Ru(CO)3(3,5‐(CF3)2‐pz)]2, (1), in high yield. This ruthenium complex has been characterized by spectroscopic methods, revealing a molecular structure similar to that of the diosmium analogue [Os(CO)3(3,5‐(CF3)2‐pz)]2. Thermogravimetric analysis (TGA) of complex 1 showed an enhanced volatility compared to the parent carbonyl compound Ru3(CO)12 and the closely related, unsaturated 3,5‐di‐tert‐butyl pyrazole complex (2) [Ru2(CO)5(3,5‐t‐Bu2‐pz)2]. Using complex 1 as the CVD source reagent, ruthenium metal with a preferred (002) orientation can be deposited at 400 °C using H2 as the carrier gas. If, however, O2 is used as the carrier gas, RuO2 thin films with a (101) orientation are obtained. The as‐deposited metal thin films were characterized by various surface techniques, as well as by electrical resistivity measurements.
Gas Phase Study of Systems for the CVD of Silver
Authors: Haase T. , Kohse‐Höinghaus K. , Atakan B. , Schmidt H. , Lang H.
Published: June 2003

Suitable strategies for the deposition of silver require knowledge of the interplay of gas phase and surface chemistry, hence the gas phase of several potential silver(I) precursor systems have been analyzed by molecular beam mass spectrometry. Specifically, the decomposition of silver(I) trifluoroacetate, silver(I) pentafluoropropionate, (trifluoroacetato)bis(tri‐n‐butylphosphine) silver(I), and (pentafluoropropionato)bis(tri‐n‐butylphosphine) silver(I) have been investigated under hot‐wall CVD conditions. The experiments show that, under the conditions investigated, the silver carboxylates [AgO2CR] (R = CF3, C2F5) are not suitable, while the phosphane‐stabilized silver(I) carboxylates [(n‐Bu3P)2AgO2CR] (R = CF3, C2F5) are promising candidates. The thermal stability and potential formation mechanisms of the observed silver‐containing fragments are discussed.
Synthetic Strategies for Dehydrobenzo[n]annulenes
Authors: Marsden Jeremiah A. , Palmer Grant J. , Haley Michael M.
Published: June 2003

Dehydrobenzoannulenes have accrued great interest due to their potential uses such as hosts for binding guest molecules and precursors to fullerenes and other carbon‐rich materials, as well as their unique properties such as conductivity or superconductivity and nonlinear optical effects. These systems have seen numerous synthetic strategies employed in their construction over the past 50 years. As alkyne chemistry has developed more recently, annulene networks with greater complexity have been possible and the field has seen a vast resurgence. This article gives an account of synthetic methods developed for the preparation of annulenic systems and describes some of the interesting observed properties. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
(Schiff‐base)vanadium(V) Complex‐Catalyzed Oxidations of Substituted Bis(homoallylic) Alcohols − Stereoselective Synthesis of Functionalized Tetrahydrofurans
Authors: Hartung Jens , Drees Simone , Greb Marco , Schmidt Philipp , Svoboda Ingrid , Fuess Hartmut , Murso Alexander , Stalke Dietmar
Published: June 2003

Vanadium(V) complexes 4 have been prepared from tridentate Schiff‐base ligands 3 and VO(OEt)3. All vanadium(V) compounds were characterized (IR, UV/Vis, and 51V NMR spectroscopy, and in selected examples by X‐ray diffraction analysis) and were applied as oxidation catalysts for the stereoselective synthesis of functionalized tetrahydrofurans 2 starting from substituted bis(homoallylic) alcohols 1 (mono‐ or trisubstituted C−C double bonds). Oxidation of secondary or tertiary 1‐alkyl‐, 1‐vinyl‐, or 1‐phenyl‐substituted 5,5‐dimethyl‐4‐penten‐1‐ols under optimized conditions [TBHP as primary oxidant and 1,2‐(amino)indanol‐derived vanadium(V) reagent 4g as catalyst] provided 2,5‐cis‐configured tetrahydrofurans in synthetically useful yields and diastereoselectivities (22−96% de). On the other hand, trans‐disubstituted oxolanes (62%−96 de) were obtained from oxidations of 2‐ or 3‐alkyl‐ and 2‐ or 3‐phenyl‐substituted 5,5‐dimethyl‐4‐penten‐1‐ols bis(homoallylic) alcohols. Treatment of 4‐penten‐1‐ols (i.e. substrates with monosubstituted olefinic π‐bonds) with TBHP and catalytic amounts of vanadium(V) complex 4g furnished trans‐disubstituted tetrahydrofurans as major products (20−96% de), no matter whether an alkyl or a phenyl substituent was located in position 1, 2, or 3 of the alkenol chain. The mechanism of this reaction has been investigated in detail. Based on results from 51V NMR spectroscopy and competition kinetics, it proceeds by a transition metal−peroxy pathway. In an initial step, TBHP coordinates to, for example, N‐(2‐oxidophenyl)salicylideniminato‐derived vanadium complex 4a. Subsequent alkenol binding gives rise to a “loaded” vanadium(V) peroxy complex (e.g. 60) which facilitates diastereoselective oxygen transfer, presumably onto a coordinated substrate. This step leads to the formation of functionalized tetrahydrofurans as major products. TBHP binding to the remaining vanadium(V) complex then allows a regeneration of the active oxidant, for example peroxy complex 57. The origin of the observed diastereoselectivity in this oxidation has been studied in an independent stereochemical analysis. Thus, diastereomerically enriched epoxy alcohol (1R,4R)‐10 was prepared. Its treatment with 1,2‐(amino)indanol‐derived vanadium complex 4g affords a 91:9 mixture of cis‐2‐(1‐hydroxy‐1‐methylethyl)‐5‐(phenyl)tetrahydrofuran (cis‐6) and cis‐2,2‐dimethyl‐6‐(phenyl)tetrahydropyran‐3‐ol (cis‐7). Similarly, a 39:61 mixture of heterocycles trans‐6 and trans‐7 was obtained from epoxy alcohol (1S,4R)‐10, if treated with Lewis acid 4g. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Application of Nim‐2,6‐Dimethoxybenzoyl Histidine in Solid‐Phase Peptide Synthesis
Authors: Zaramella Simone , Strömberg Roger , Yeheskiely Esther
Published: June 2003

Fmoc‐histidine derivatives protected with 2,6‐dimethoxybenzoyl (2,6‐Dmbz) units, either on the τ‐ (1) or on the π‐position (2) of the imidazole residue, have been prepared and applied to the synthesis of the dipeptide Fmoc‐His(2,6‐Dmbz)‐Val‐OMe, with high coupling efficiencies (99 and 95%, respectively) and low racemization (0.3 and 0.1%, respectively), as ascertained by HPLC analysis on the fully protected dipeptides. In addition, the hexapeptide H‐Ala‐Ser‐Val‐His‐Val‐Phe‐OH (I) has been synthesized on a solid support employing the novel building blocks 1 and 2 as well as commercially available Fmoc‐His(τ‐Trt)‐OH (3). The crude deprotected products were analyzed by reverse‐phase HPLC and mass spectrometry, which indicated that when the τ‐protected derivatives 1 and 3 were employed the products were of comparable quality (93−94% major peak). The hexapeptide synthesized with the π‐protected histidine 2 was contaminated with a product corresponding to 2,6‐Dmbz‐His‐Val‐Phe‐OH (12), which was probably formed through the intramolecular acyl transfer of a 2,6‐Dmbz unit from the π‐nitrogen atom to the α‐amino group of the N‐terminal histidine unit upon removal of the Fmoc group. This side reaction was insignificant (less than 0.5%) when using the τ‐protected derivative 1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Syntheses and UV/Vis Properties of Amino‐Functionalized Fulgimides
Authors: Otto Bernhard , Rück‐Braun Karola
Published: June 2003

Functionalized fulgimides are regarded as a promising class of photochromic compounds for modulating the structure and function of biomolecules. A new synthetic route to fulgimides bearing amino‐functionalized substituents at the imide nitrogen atom has been developed. The synthesis of the fulgimides has been achieved by base‐catalyzed cyclization of phenacyl esters of the succinamic acids derived from fulgides and N‐Boc‐protected alkyl‐ and aryl‐substituted diamines with triethylamine or tert‐butyllithium. The UV/Vis spectroscopic data and the photochromic properties of these new compounds have been studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Diastereoselective Synthesis of 1‐Benzyltetrahydroisoquinoline Derivatives from Amino Acids by 1,4 Chirality Transfer
Authors: Zawadzka Anna , Leniewski Andrzej , Maurin Jan K. , Wojtasiewicz Krystyna , Siwicka Aleksandra , Blachut Dariusz , Czarnocki Zbigniew
Published: June 2003

L‐Amino acids (L‐Ala, L‐Phe, L‐Val, L‐Pro) were used as a source of chirality in the diastereoselective synthesis of tetrahydroisoquinoline derivatives. The key step was the Pictet−Spengler condensation of ketoamides 4 and 10, which proceeded under very mild conditions. L‐Ala, L‐Phe and L‐Val gave rise the R‐configuration at the newly formed stereogenic center. Surprisingly, L‐Pro gave the opposite result. The stereochemistry of 6d and 12a were established on the basis of X‐ray crystallographic data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Novel Tetrahydropyran‐Based Dipeptide Isosters by Overman Rearrangement of 2,3‐Didehydroglycosides
Authors: Kriek Nicole M. A. J. , Hout Elise van der , Kelly Paskal , Meijgaarden Krista E. van , Geluk Annemieke , Ottenhoff Tom H. M. , Marel Gijs A. van der , Overhand Mark , Boom Jacques H. van , Valentijn A. Rob P. M. , Overkleeft Herman S.
Published: June 2003

Differently functionalized tetrahydropyran‐based dipeptide isosters have been efficiently synthesized from 3,4,6‐tri‐O‐acetyl‐D‐glucal. Analogues of the hsp65 p2−13 epitope of Mycobacterium tuberculosis and Mycobacterium leprae were prepared by replacement of the Ala−Tyr or Glu−Glu moiety in the native dodecapeptide with the prepared dipeptide isosters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Mechanism of Selective and Unselective Enclathration by a Host Compound Possessing Open, Flexible Host Frameworks
Authors: Nakano Kazunori , Mochizuki Eiko , Yasui Nobuyoshi , Morioka Kyoichi , Yamauchi Yukinori , Kanehisa Nobuko , Kai Yasushi , Yoswathananont Nungruethai , Tohnai Norimitsu , Sada Kazuki , Miyata Mikiji
Published: June 2003

Molecular recognition of o‐, m‐, and p‐xylenes (oX, mX, and pX) through enclathration of cholic acid (CA) is described. All of the xylenes give lattice inclusion crystals with CA, and crystallographic studies reveal that they are included in different open host frameworks. In particular, oX has two polymorphs, depending on the recrystallization temperatures. Competitive recrystallization from mixtures of xylenes resulted in selective enclathrations and the formation of racemic mixed crystals. In the presence of an equimolar amount of oX, CA selectively includes mX or pX in the host frameworks, which are identical to those obtained from the pure mX or pX, respectively. The low affinity of oX is explained in terms of a lower stability of CA·oX than of the other two complexes, as judged from the low PCcavity, the volume ratio of the guest compound to the host cavity. Meanwhile, mixtures of mX and pX yield inclusion crystals that accommodate both of the guests. These have the same open host framework as obtained from pure mX, and the guest components are disordered statically in the host cavity. The ratios of the xylene mixtures in the single crystals are similar to those in the original recrystallization mixtures, and also in the bulk crystals, indicating that CA forms mixed crystals of mX and pX. This non‐selectivity is attributed to the similar stabilities of CA·mX and CA·pX, according to the moderate PCcavity. The inclusion behavior of CA from mixtures of xylenes is quite similar to chiral recognition by diastereomer‐salt methods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Effect of High Pressure on the Heck Reaction − A Contribution to a Deeper Understanding of the Mechanism
Authors: Buback Michael , Perković Thomas , Redlich Stefan , Meijere Armin de
Published: June 2003

The influence of high pressure on the Heck reactions of iodobenzene with methyl, ethyl and tert‐butyl acrylate, and of both 4‐nitrophenyl iodide and 4‐nitrophenyl triflate with methyl acrylate, has been studied for the first time by quantitative on‐line FT‐IR spectroscopy. Reaction rates and activation parameters (ΔH‡, ΔS‡, ΔV‡) were determined at temperatures between 50 and 120 °C and pressures up to 3000 bar. A clear influence on the kinetics of the reactions was observed by the nature of the leaving group and by the steric and electronic features of the acrylate. tert‐Butyl acrylate, which is more electron‐rich than methyl acrylate according to PES measurements, was found to react 1.4‐times faster on average than methyl acrylate and, at elevated pressures, triflate turned out to be a better leaving group than iodide. Thus, the observed activation volume for the reaction of iodobenzene with tert‐butyl acrylate (ΔV‡ = −12 cm3 mol−1) is more negative than that of the reaction of iodobenzene with ethyl acrylate (ΔV‡ = −7 cm3 mol−1) or methyl acrylate (ΔV‡ = −5 cm3 mol−1). For the variation of the leaving group in 4‐nitrophenyl iodide and 4‐nitrophenyl triflate, the activation volumes for the reaction of each with methyl acrylate are −9 and −37 cm3 mol−1, respectively. The results suggest that the rate‐determining step of the overall reaction is not the oxidative addition, but is either the alkene coordination or the subsequent carbopalladation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of a Cellobiosylated Dimer and Trimer and of Cellobiose‐Coated Polyamidoamine (PAMAM) Dendrimers to Study Accessibility of an Enzyme, Cellodextrin Phosphorylase
Authors: Choudhury Ambar K. , Kitaoka Mitomitsu , Hayashi Kiyoshi
Published: June 2003

To examine the accessibility of the enzyme cellodextrin phosphorylase (CDP) towards multivalent cluster carbohydrates, the cellobiosylated dimer 10 and trimer 12, as well as the cellobiose‐coated PAMAM dendrimers 14, 16, 18, 20 and 22, with four, eight, sixteen, thirty‐two and sixty‐four cellobiose units at the outer surface of PAMAM dendrimers, respectively, have been synthesized for the first time and used as acceptor substrates for the enzyme CDP. It was found that CDP was able to transfer a glucosyl moiety from glucose‐1‐phosphate (Glc‐1‐P) into these synthesized cluster cellobiosylated glycoconjugates and cellobiose‐coated PAMAM dendrimers, which were thus acceptor substrates for CDP. It was found that the ability of CDP to interact with smaller cellobiosylated glyconjugates and with PAMAM dendrimers containing up to eight cellobiose units was similar to that seen with cellobiose. However, this capability of CDP was somewhat lessened with the PAMAM dendrimer containing sixteen cellobiose moieties and dramatically decreased towards PAMAM dendrimers with thirty‐two and sixty‐four cellobiose units. This might be due to their steric bulk, CDP enzyme no longer being able to hold them properly on its active site. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Successive Cycloadditions between 4‐Fluoro‐5‐trifluoromethyl‐1,2‐dithiole‐3‐thione and Dimethyl Acetylenedicarboxylate: New Fluorinated Thiaheterocycles through New Reaction Mechanisms
Authors: Timoshenko Vadim M. , Bouillon Jean‐Philippe , Chernega Alexander N. , Shermolovich Yuriy G. , Portella Charles
Published: June 2003

The cycloaddition reaction between dimethyl 2‐(1‐fluoro‐2‐trifluoromethyl‐2‐thioxoethylidene)‐1,3‐dithiole‐4,5‐dicarboxylate and dimethyl acetylenedicarboxylate proceeds efficiently under irradiation conditions in air. A study of the reaction conditions resulted in the proposal of a chain mechanism initiated by a photochemically induced single‐electron transfer to oxygen. On the other hand, the cycloadduct can be transformed into a rearranged hydroxylated product by filtration through silica gel. Either the cycloadduct or its rearranged product can be obtained selectively in a one‐pot process from the parent 1,2‐dithiole‐3‐thione. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Reactivity of (Z)‐5‐Acetyl‐3‐aryl‐2,3‐dihydro‐2‐[(thioacyl)methylene]1,3,4‐thiadiazoles: A Surprising Base‐Induced Conversion into 3‐(N‐arylamino)thiophenes
Authors: Benincori Tiziana , Pilati Tullio , Rizzo Simona , Sada Mara , Sannicolò Franco
Published: June 2003

We report the reactivity shown by two classes of rarely investigated heterocycles, the 5‐acetyl‐2,3‐dihydro‐3‐phenyl‐2‐(phenylmethylene)‐1,3,4‐thiadiazoles (6) and the 5alkanoyl‐3‐aryl‐2,3‐dihydro‐2‐[(thioacyl)methylene]‐1,3,4thiadiazoles 1a−e. In both cases, strong bases promote cleavage of the thiadiazole ring with loss of thiocyanate anion, generating N‐arylketeneimines and N‐aryl(thioacyl)keteneimines 5, respectively. These very reactive species undergo either nucleophilic addition or [4+2] cycloaddition reactions involving the thioacyl function. The most surprising result was found in the reactions of the 5‐acetyl‐3‐aryl‐2,3‐dihydro‐2‐[(thioacyl)methylene]‐1,3,4‐thiadiazoles 1a,d,e, which afford 3‐(arylamino)thiophenes 2, 10, and 14 as the main products. This serendipitous transformation, which seems to be rather general, probably involves an intermediate step in which the acetyl group of the substrates is converted into ketene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Flash Vacuum Thermolysis of 1‐Azabicyclo[1.1.0]butanes. Photoelectron Spectrum of 3‐Phenyl‐2‐azabuta‐1,3‐diene
Authors: Bartnik Romuald , Baylère Patrick , Chrostowska Anna , Galindo Alberto , Leśniak Stanislaw , Pfister‐Guillouzo Geneviève
Published: June 2003

The reaction behaviour of 1‐azabicyclo[1.1.0]butanes under flash vacuum thermolysis (FVT) conditions was studied. It has been found that the thermal rearrangement of title compounds produces unstable 2‐aza‐1,3‐dienes. The formation of these products was established by reduction, by Diels−Alder reactions and by UV photoelectron spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Enantioselective Synthesis of the Ester Side Chain of Homoharringtonine
Authors: Keller Laurent , Dumas Françoise , d’Angelo Jean
Published: June 2003

Details of the synthesis of the methyl ester of the side chain of homoharringtonine, a natural product with antileukemic properties, are reported below. The key tactical element involved a Michael addition between the known chiral imine 4 and 2‐acetoxyacrylonitrile (5), furnishing the adduct (2R,1′R)‐6 with a high degree of regio‐ and stereoselectivity. This adduct was then converted into the target compound (R)‐2 by a linear sequence of ten chemical operations, in 6.0% overall yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis and Reactivity of a New Heptacarbon Chain Carboxonium Salt − Access to a New Class of Streptocyanine Dyes
Authors: Izquierdo Albert , Payrastre Corinne , Gornitzka Heinz , Madaule Yves
Published: June 2003

A new highly reactive heptacarbon chain carboxonium salt 1 was synthesized. It leads, by action of various amines and hydrazone, to a new class of symmetrical heptacarbon chain streptocyanine dyes 2−6. A hemicarboxonium salt 7, which leads to a dissymmetrical streptocyanine, was also obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A life‐cycle assessment (LCA) model for cables based on the fire‐LCA model
Authors: Simonson Margaret , Andersson Petra , Emanuelsson Viktor , Stripple Håkan
Published: June 2003

A novel life‐cycle assessment (LCA) model has been developed for the investigation of the environmental impact of the choice of material in cable production. In the first application polyolefin based material and PVC material is used. In both cases equivalent fire behaviour is assumed and a fire model is established based on existing fire statistics. This study represents the second full application of the fire‐LCA model.

In this paper the new ‘cables fire‐LCA’ model will be presented together with the results of this first application. Aspects such as end‐of‐life scenarios, fire statistics, and fire scenarios and large scale fire performance of cables are discussed together with details of the straw LCA model defined for cables and the results of four different end‐of‐life scenarios. Copyright © 2003 John Wiley & Sons, Ltd.
Charring rates and temperature profiles of wood sections
Authors: Frangi Andrea , Fontana Mario
Published: June 2003

A research project was carried out at the Swiss Federal Institute of Technology (ETH) to study the fire behaviour of hollow core timber slabs and timber‐concrete composite slabs. This paper describes the main results of the basic fire behaviour of timber measured in the study. The first part of the analysis looks at the charring rate of timber. In the second part a new calculation model for the temperature development in wood members exposed to the standard ISO‐fire is presented and compared with the fire test results. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical simulation of three‐dimensional free surface flows
Authors: Maronnier V. , Picasso M. , Rappaz J.
Published: June 2003

A numerical model is presented for the simulation of complex fluid flows with free surfaces in three space dimensions. The model described in Maronnier et al. (J. Comput. Phys. 1999; 155(2) : 439) is extended to three dimensional situations. The mathematical formulation of the model is similar to that of the volume of fluid (VOF) method, but the numerical procedures are different.

A splitting method is used for the time discretization. At each time step, two advection problems—one for the predicted velocity field and the other for the volume fraction of liquid—are to be solved. Then, a generalized Stokes problem is solved and the velocity field is corrected. Two different grids are used for the space discretization. The two advection problems are solved on a fixed, structured grid made out of small cubic cells, using a forward characteristic method. The generalized Stokes problem is solved using continuous, piecewise linear stabilized finite elements on a fixed, unstructured mesh of tetrahedrons.

The three‐dimensional implementation is discussed. Efficient postprocessing algorithms enhance the quality of the numerical solution. A hierarchical data structure reduces memory requirements. Numerical results are presented for complex geometries arising in mold filling. Copyright © 2003 John Wiley & Sons, Ltd.
A non‐linear k–ε model with realizability for prediction of flows around bluff bodies
Authors: Kimura Ichiro , Hosoda Takashi
Published: June 2003

The incompressible flow around bluff bodies (a square cylinder and a cube) is investigated numerically using turbulence models. A non‐linear k–ε model, which can take into account the anisotropy of turbulence with less CPU time and computer memory then RSM or LES, is adopted as a turbulence model. In tuning of the model coefficients of the non‐linear terms are adjusted through the examination of previous experimental studies in simple shear flows. For the tuning of the coefficient in the eddy viscosity (=Cμ), the realizability constraints are derived in three types of basic 2D flow patterns, namely, a simple shear flow, flow around a saddle and a focal point. Cμ is then determined as a function of the strain and rotation parameters to satisfy the realizability. The turbulence model is first applied to a 2D flow around a square cylinder and the model performance for unsteady flows is examined focussing on the period and the amplitude of the flow oscillation induced by Karman vortex shedding. The applicability of the model to 3D flows is examined through the computation of the flow around a surface‐mounted cubic obstacle. The numerical results show that the present model performs satisfactorily to reproduce complex turbulent flows around bluff bodies. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical simulation of turbulent flow through series stenoses
Authors: Lee T. S. , Liao Wei , Low H. T.
Published: June 2003

The flow fields in the neighbourhoods of series vascular stenoses are studied numerically for the Reynolds numbers from 100 to 4000, diameter constriction ratios of 0.2–0.6 and spacing ratios of 1, 2, 3, 4 and ∞. In this study, it has been further verified that in the laminar flow region, the numerical predictions by k–ω turbulence model matched those by the laminar‐flow modelling very well. This suggests that the k–ω turbulence model is capable of the prediction of the laminar flow as well as the prediction of the turbulent stenotic flow with good accuracy. The extent of the spreading of the recirculation region from the first stenosis and its effects on the flow field downstream of the second stenosis depend on the stenosis spacing ratio, constriction ratio and the Reynolds number. For c1 = 0.5 with c2 ≤ c1, the peak value of wall vorticity generated by the second stenosis is always less than that generated by the first stenosis. However, the maximum centreline velocity and turbulence intensity at the second stenosis are higher than those at the first stenosis. In contrast, for c1 = 0.5 with c2 = 0.6, the maximum values at the second stenosis are much higher than those at the first stenosis whether for centreline velocity and turbulence intensity or for wall vorticity. The peak values of the wall vorticity and the centreline disturbance intensity both grow up with the Reynolds number increasing. The present study shows that the more stenoses can result in a lower critical Reynolds number that means an earlier occurrence of turbulence for the stenotic flows. Copyright © 2003 John Wiley & Sons, Ltd.
Dispersion and stability analyses of the linearized two‐dimensional shallow water equations in boundary‐fitted co‐ordinates
Authors: Sankaranarayanan S. , Spaulding Malcolm L.
Published: June 2003

In the present investigation, a Fourier analysis is used to study the phase and group speeds of a linearized, two‐dimensional shallow water equations, in a non‐orthogonal boundary‐fitted co‐ordinate system. The phase and group speeds for the spatially discretized equations, using the second‐order scheme in an Arakawa C grid, are calculated for grids with varying degrees of non‐orthogonality and compared with those obtained from the continuous case. The spatially discrete system is seen to be slightly dispersive, with the degree of dispersivity increasing with an decrease in the grid non‐orthogonality angle or decrease in grid resolution and this is in agreement with the conclusions reached by Sankaranarayanan and Spaulding (J. Comput. Phys., 2003; 184: 299–320). The stability condition for the non‐orthogonal case is satisfied even when the grid non‐orthogonality angle, is as low as 30° for the Crank Nicolson and three‐time level schemes. A two‐dimensional wave deformation analysis, based on complex propagation factor developed by Leendertse (Report RM‐5294‐PR, The Rand Corp., Santa Monica, CA, 1967), is used to estimate the amplitude and phase errors of the two‐time level Crank–Nicolson scheme. There is no dissipation in the amplitude of the solution. However, the phase error is found to increase, as the grid angle decreases for a constant Courant number, and increases as Courant number increases. Copyright © 2003 John Wiley & Sons, Ltd.
A new VOF‐based numerical scheme for the simulation of fluid flow with free surface. Part II: application to the cavity filling and sloshing problems
Authors: Soo Kim Min , Sun Park Jong , Lee Woo Il
Published: June 2003

Finite element analysis of fluid flow with moving free surface has been performed in 2‐D and 3‐D. The new VOF‐based numerical algorithm that has been proposed by the present authors (Int. J. Numer. Meth. Fluids, submitted) was applied to several 2‐D and 3‐D free surface flow problems. The proposed free surface tracking scheme is based on two numerical tools; the orientation vector to represent the free surface orientation in each cell and the baby‐cell to determine the fluid volume flux at each cell boundary. The proposed numerical algorithm has been applied to 2‐D and 3‐D cavity filling and sloshing problems in order to demonstrate the versatility and effectiveness of the scheme. The proposed numerical algorithm resolved successfully the free surfaces interacting with each other. The simulated results demonstrated applicability of the proposed numerical algorithm to the practical problems of large free surface motion. It has been also demonstrated that the proposed free surface tracking scheme can be easily implemented in any irregular non‐uniform grid systems and can be extended to 3‐D free surface flow problems without additional efforts. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical simulation of unsteady multidimensional free surface motions by level set method
Authors: Yue Wusi , Lin Ching‐Long , Patel Virendra C.
Published: June 2003

This paper presents a numerical method that couples the incompressible Navier–Stokes equations with the level set method in a curvilinear co‐ordinate system for study of free surface flows. The finite volume method is used to discretize the governing equations on a non‐staggered grid with a four‐step fractional step method. The free surface flow problem is converted into a two‐phase flow system on a fixed grid in which the free surface is implicitly captured by the zero level set. We compare different numerical schemes for advection of the level set function in a generalized curvilinear format, including the third order quadratic upwind interpolation for convective kinematics (QUICK) scheme, and the second and third order essentially non‐oscillatory (ENO) schemes. The level set equations of evolution and reinitialization are validated with benchmark cases, e.g. a stationary circle, a rotating slotted disk and stretching of a circular fluid element. The coupled system is then applied to a travelling solitary wave, and two‐ and three‐dimensional dam breaking problems. Some interesting free surface phenomena are revealed by the computational results, such as, the large free surface vortices, air entrapment and splashing of the water surge front. The computational results are in excellent agreement with theoretical predictions and experimental data, where they are available. Copyright © 2003 John Wiley & Sons, Ltd.
Fourth‐order finite difference scheme for the incompressible Navier–Stokes equations in a disk
Authors: Lai Ming‐Chih
Published: June 2003

We develop an efficient fourth‐order finite difference method for solving the incompressible Navier–Stokes equations in the vorticity‐stream function formulation on a disk. We use the fourth‐order Runge–Kutta method for the time integration and treat both the convection and diffusion terms explicitly. Using a uniform grid with shifting a half mesh away from the origin, we avoid placing the grid point directly at the origin; thus, no pole approximation is needed. Besides, on such grid, a fourth‐order fast direct method is used to solve the Poisson equation of the stream function. By Fourier filtering the vorticity in the azimuthal direction at each time stage, we are able to increase the time step to a reasonable size. The numerical results of the accuracy test and the simulation of a vortex dipole colliding with circular wall are presented. Copyright © 2003 John Wiley & Sons, Ltd.
In the Cockpit of the Fly
Authors: Egelhaaf Martin , Kern Roland , Kurtz Rafael , Warzecha Anne‐Kathrin
Published: June 2003

Small brains can completely outclass large ones in their performance. Thus the fly has proved to be an outstanding model system for image processing in the brain
A Treatise on Life with Camels
Authors: Köhler‐Rollefson Ilse‐Ulrike
Published: June 2003

Traditional herding cultures consider close social association with their animals to be a central pillar of their culture
Commentary: An Impetus for Engineers and Computer Scientists
Authors: Nehmer Jürgen
Published: June 2003

New options for junior scientists and schooars to qualify — early independence and international networking are being promoted
Communication with the Locked‐in
Authors: Birbaumer Niels , Kübler Andrea
Published: June 2003

An electronic system for thought translation is opening up the world again to the paralysed
How High can a Range of Mountains get?
Authors: Ring Uwe
Published: June 2003

Rocks from the depths of the Earth can be found on its surface. They provide information on the thickness of continents and permit conclusions to be drawn regarding orogenic processes