bluuebunny/crossref_metadata_2025_split huggingface dataset:
Das kreative Uhrwerksuniversum : Experiment zum Nachmachen und Nachdenken
Authors: Euler Manfred 
Published: May 2004

AbstractEs werden Experimente vorgestellt, die Phänomene der Selbstorganisation bei gekoppelten Metronomen untersuchen. Bei geeigneter Wechselwirkung sind diese mechanischen Uhren in der Lage, ihre Schwingungen zu synchronisieren und kohärentes Verhalten zu entwickeln. Der Vorgang der Synchronisation wird qualitativ im Waschbrettmodell diskutiert. Die Modellexperimente vermitteln Einsichten in die allgegenwärtige Rolle von Synchronisationsprozessen in der Biologie, insbesondere im Bereich der sensorischen Verarbeitung und bei kognitiven Prozessen.
Auxin schafft Ordnung im Blätterwald
Authors: Brennicke Axel 
Published: May 2004

AbstractSchönheit in der Natur ist oft eine unverhoffte Symmetrie im Chaos des Lebendigen. Bei Pflanzen bestechen die Widersprüche zwischen den individuell so unterschiedlichen Blättern und ihren regelmäßigen Anordnungen. Diese symmetrischen Folgen von Blattanlagen, Blüten oder Samen beruhen auf der kontrollierten Verteilung des Wachstumshormons Auxin. Junge Blätter in den wachsenden Pflanzenteilen leiten das Hormon um, so dass erst in einem bestimmten Abstand das nächste Blatt entsteht.
Peptid‐Aptamere: Molekulare Werkzeuge gegen Krebs?
Authors: Nagel‐Wolfrum Kerstin 
Published: May 2004

AbstractTrotz des Fortschritts in der Tumortherapie stellt Krebs nach Erkrankungen des Herz‐Kreislaufsystems in Deutschland die zweithäufigste Todesursache dar. Auf der Suche nach neuen therapeutischen Ansatzpunkten haben Forscher ein Peptid gefunden, das einen für Tumorzellen essenziellen Signalweg blockiert und in den Tumorzellen den programmierten Zelltod auslöst. Dieses Peptid unterscheidet sich in seinem Wirkmechanismus gänzlich von anderen Krebsmedikamenten: Es inhibiert nicht die katalytische Funktion von enzymatisch aktiven Molekülen, sondern blockiert einen entscheidendenTranskriptionsfaktor.
Anatomy and blood supply of the subgaleal fascia flap
Authors: Casoli Vincent , Dauphin Nicolas , Taki Christina , Pelissier Philippe , Boudard Philippe , Caix Philippe , Delmas Vincent 
Published: May 2004

AbstractThe subgaleal fascia (SGF) is a distinct layer in the temporal fossa situated between the superficial fascia and galea aponeurotica and the temporal fascia covering the superficial surface of the temporal muscle. The SGF is used most frequently for otologic reconstruction. Reviewing the literature, however, showed many contradictory findings about dissection of an independent SGF layer, its blood supply, and the possibility of harvesting it as part of a combined flap. Our study, carried out on ten fresh cadavers, presents a detailed view of the blood supply of the SGF to develop a safe method of harvesting an inferior‐based SGF. Our systematic plane‐by‐plane approach, associated with a transparent grid applied on each dissection, allowed us to quantify the branches from each plane and to localize precisely their entering sites from a reference “zygomatic point.” The SGF had no ascending axial vascular supply entering from its base; according to our results, therefore, the SGF could not be harvested alone as an inferior pedicled flap down to the zygomatic arch. It may be feasible, however, to harvest a SGF flap when a strip of the superficial fascia is associated with its middle third. Therefore, we suggest that an average height of 5.4 cm of superficial fascia should be included in an inferior‐based pedicle of a SGF. Clin. Anat. 17:392–399, 2004. © 2004 Wiley‐Liss, Inc.
Alternative approaches for regional ulnar nerve blockade: A cadaveric study
Authors: Lizamore N. , Venter E. , Boon J.M. 
Published: May 2004

AbstractWrist blockade is a safe and effective alternative to general anesthesia in surgery of hand injuries. With regard to the ulnar nerve, the volar approach is used, where the needle passes through or medial to the flexor carpi ulnaris tendon; however, the ulnar artery is at risk because the needle may accidentally penetrate it, causing profuse bleeding. Alternatively, the wrist may be approached medially, the ulnar approach, and the needle tip placed posterior to the flexor carpi ulnaris tendon. To determine which of these methods may be preferable for avoiding ulnar artery injury, needles were inserted into the wrist area of cadaver hands (n = 57) using the volar and ulnar approaches; detailed dissection of the region around the inserted needles was subsequently carried out. The position of the ulnar nerve relative to the ulnar artery and injury to the artery was documented. Damage to the ulnar artery using the volar approach was 36.8% (21/57 cases) compared to no (0%) injury observed using the ulnar approach. At the level of the wrist crease just proximal to the pisiform bone, the ulnar nerve was medial to the artery in 92.9% (53/57) of cases, medial and posterior in 5.3% (3/57), and anterior to the artery in 1.8% (1/57) of cases. This study suggests that in cases where ulnar artery pulsation is not reliable, the ulnar approach may be preferable for ulnar nerve blockade due to an increased incidence of ulnar artery penetration with the volar approach. Clin. Anat. 17:373–377, 2004. © 2004 Wiley‐Liss, Inc.
Great cardiac vein variations
Authors: Bales Gerald S. 
Published: May 2004

AbstractA novel variation in the relationship of the great cardiac vein to the circumflex artery was observed in an otherwise normal cadaver heart. Vessels originated and terminated normally, but in their midcourse they were twisted around each other such that each made one complete loop around the other. This variation did not seem to be involved in any pathologies. Variations in the course of the great cardiac vein have been little studied until recently, but their simplicity emphasizes the uniqueness of our intertwined case. Commonly, the great cardiac vein varies with respect to presence, location, and the superficial or deep relationship of single crossings of the anterior interventricular and circumflex arteries. Although rare, the intertwined variation described in the present case may have important basic science implications for understanding mechanisms of vasculo‐angiogenesis, and clinical implications for catheter‐based procedures and surgeries in the region of the coronary sulcus. Also, a review of great cardiac vein variations is presented herein. Clin. Anat. 17:436–443, 2004. © 2004 Wiley‐Liss, Inc.
Unusual variation of the inferior attachment of the pectoralis minor muscle
Authors: Turan‐Ozdemir S. , Cankur N.S. 
Published: May 2004

AbstractAn unusual inferior attachment of pectoralis minor muscle was found on the right side of a male cadaver. The tendinous attachment, originating only from the 5th rib, was detected during the routine practical dissections. There were no other associated features in the thoracic region of this cadaver. We believe that this variation that has not been reported previously in the literature, should be taken into consideration by the surgeons. Clin. Anat. 17:416–417, 2004. © 2004 Wiley‐Liss, Inc.
Yttrium and Lanthanide Diphosphanylamides: Syntheses and Structures of Complexes with one {(Ph2P)2N}− ligand in the Coordination Sphere
Authors: Roesky Peter W. , Gamer Michael T. , Marinos Nicolas 
Published: May 2004

AbstractTreatment of the recently reported potassium salt [K(thf)n][N(PPh2)2] (n=1.25, 1.5) with anhydrous yttrium or lanthanide trichlorides in THF leads after crystallization from THF/n‐pentane (1:2) to the monosubstituted diphosphanylamide complexes [LnCl2{(Ph2P)2N}(thf)3] (Ln=Y, Sm, Er, Yb). The single‐crystal X‐ray structures of these complexes show that the metal atoms are surrounded by seven ligands in a distorted pentagonal bipyramidal arrangement, in which the chlorine atoms are located in the apical positions. The diphosphanylamide ligand is always η2‐coordinated through the nitrogen atom and one phosphorus atom. Further reaction of [SmCl2{(Ph2P)2N}(thf)3] with K2C8H8 or reaction of [LnI(η8‐C8H8)(thf)3] with [K(thf)n][N(PPh2)2] in THF gives the corresponding cyclooctatetraene complexes [Ln{(Ph2P)2N}(η8‐C8H8)(thf)2] (Ln=La, Sm). The single crystals of these compounds contain enantiomerically pure complexes. Both compounds adopt a four‐legged piano‐stool conformation in the solid state. The structures of the A and the C enantiomers were established by single‐crystal X‐ray diffraction. The more soluble bistrimethylsilyl cyclooctatetraene complex [Y{(Ph2P)2N}(η8‐1,4‐(Me3Si)2C8H6)(thf)2] was obtained by transmetallation of Li2[1,4‐(Me3Si)2C8H6] with anhydrous yttrium trichloride in THF followed by the addition of one equivalent of [K(thf)n][N(PPh2)2]. The 89Y NMR signal of the complex is split up into a triplet, supporting other observations that the phosphorus atoms are chemically equivalent in solution and, thus, dynamic behavior of the ligand in solution can be anticipated.
Molecular Evolution Using Intramolecular Acyl Migration on myo‐Inositol Benzoates with Thermodynamic and Kinetic Selectors
Authors: Ahn Young‐Hoon , Chang Young‐Tae 
Published: May 2004

AbstractA molecular evolution model was successfully demonstrated by combining the intramolecular acyl migration on inositol tribenzoates and boron selectors. The addition of boric acid to 12 members of DCL (dynamic combinatorial library) induced the dramatic amplification of myo‐I(2,4,6)Bz3 (1) with up to 94 % under thermodynamic (see Figure 1 c) control while a portion of phenyl boronic acid caused two significant different distributions: under kinetic control, the pre‐equilibrium of DCL shifted to induce the exclusive amplification of 1,4,6‐tribenzoyl myo‐inositol (7) with decrease of other members up to 82 % from the mixture (see Figure 2 b), and changed gradually to form 2,4,6‐tribenzoyl myo‐inositol (1) with up to 96 % under thermodynamic control (Figure 2 c).
Vergleich chromatographischer Reaktorkonzepte
Authors: Borren T. , Schmidt‐Traub H. 
Published: May 2004

AbstractDurch die Integration einer chemischen oder biochemischen Reaktion und einer chromatographischen Trennung in einem gemeinsamen Apparat ist es möglich, die Gleichgewichtslimitierung der Reaktion zu überwinden und die Trenneffektivität zu erhöhen. Verschiedene prozesstechnische Varianten des chromatographischen Reaktors werden vorgestellt. Aufgrund der komplexen Zusammenhänge sind Modellierung und Simulation wichtige Werkzeuge bei der Entwicklung und Gestaltung der Prozesse. Eine Übersicht über die zur Verfügung stehenden Modellansätze wird gegeben. Ein Vergleich der verschiedenen chromatographischen Simulated Moving Bed (SMB)‐Reaktoren erfolgt am Beispiel der Glucose‐Isomerisierung. In Abhängigkeit von der jeweiligen Reinheitsanforderung an den gewonnenen Fructose‐Sirup bieten unterschiedliche Integrationsgrade von Reaktion und Trennung Vorteile.
Innovative Katalysatoren zur oxidativen Dehydrierung in der Gasphase – Metallische Kurzfasern
Authors: Brüning R. , Scholz P. , Morgenthal I. , Andersen O. , Ondruschka B. 
Published: May 2004

AbstractMetallische Kurzfasern in ausgesuchter Legierungszusammensetzung und Gefügestruktur wurden auf ihre katalytische Aktivität bei der oxidativen Dehydrierung (ODH) von Propan zu Propen und von Isopropanol zu Aceton untersucht. Die über das Schmelzextraktions‐Verfahren hergestellten Kurzfasern wurden einer intensiven Charakterisierung ihrer werkstoffseitigen Eigenschaften unterworfen. Dabei kamen lichtmikroskopische, DSC‐, XRD‐, REM‐ und EDX‐Untersuchungen zum Einsatz, um Zusammenhänge zwischen der Werkstoffzusammensetzung, dem Gefüge und den katalytischen Eigenschaften zu ermitteln. Es werden ausgewählte Ergebnisse zur Temperaturabhängigkeit des Propan‐Umsatzes bzw. der Propen‐Selektivität präsentiert. So wurde Propen bei einem Propan‐Umsatz von mehr als 50 % mit einer Ausbeute von 35 % gebildet. Auch die Selektivoxidation von Isopropanol zu Aceton erfolgte mit attraktiven Ausbeuten von über 80 %. Die Ergebnisse insgesamt belegen das hohe Innovationspotenzial der Metallfaserwerkstoffe.
Enhanced axonal growth into a spinal cord contusion injury site in a strain of mouse (129X1/SvJ) with a diminished inflammatory response
Authors: Ma Manhong , Wei Ping , Wei Tao , Ransohoff Richard M. , Jakeman Lyn B. 
Published: May 2004

AbstractAfter injury in the adult central nervous system, invading and intrinsic cells contribute to the formation of a lesion site that is refractory to axonal growth. To test the hypothesis that the inflammatory response to trauma dictates the extent of axonal growth after spinal cord injury, the time course of lesion evolution was compared in two mouse strains with contrasting cellular responses to peripheral inflammatory challenge. Adult C57Bl/6 and 129X1/SvJ mice received identical contusion injuries to the mid‐thoracic spinal cord and were allowed to recover for 6 hours to 9 weeks. Both strains responded with a rapid, transient increase in chemokine expression, but the magnitude of this early response was slightly reduced in the 129X1/SvJ mice. Morphological indicators of inflammation were similar during the first week postinjury. After 7 days postinjury, however, the cellular responses differed between strains. The C57Bl/6 lesion core was chronically occupied by macrophages, devoid of astrocytes, and contained few axonal profiles. In contrast, as the macrophage density decreased a network of astrocytic processes and axons of central and peripheral origin invaded the center of the lesion site in 129X1Sv/J mice. Growth of axons in the 129X1Sv/J mice was accompanied by increased extravascular laminin in the lesion core and a reduced expression of chondroitin sulfate proteoglycan glycosaminoglycan sidechains in the periphery of the lesion. These results demonstrate that the diminished chronic inflammatory response in 129X1/SvJ mice is associated with enhanced cellular repair and increased axonal growth after spinal cord injury. J. Comp. Neurol. 474:469–486, 2004. © 2004 Wiley‐Liss, Inc.
Expression of the genes Emx1, Tbr1, and Eomes (Tbr2) in the telencephalon of Xenopus laevis confirms the existence of a ventral pallial division in all tetrapods
Authors: Brox Aurora , Puelles Luis , Ferreiro Beatriz , Medina Loreta 
Published: May 2004

AbstractTo investigate the pallial organization and the exact location and extension of the ventral pallium in amphibians, we cloned a fragment of the homeobox XenopusTbr1 (xTbr1) gene and analyzed its expression compared with that of the genes xEomes (Tbr2) and xEmx1 in the telencephalon of the frog Xenopus laevis during embryonic and larval development. The expression of xEmx1 was also analyzed in the adult frog. We compared the expression patterns of these pallial marker genes with that of the subpallial gene xDistal‐less‐4 (xDll4). Our results indicate that the whole pallium of Xenopus expresses the T‐box genes xTbr1 and xEomes (in proliferating cells and/or mantle) during embryonic and larval development, and the expression of these genes is topographically complementary to that of xDll4 in the subpallium. In addition to their massive expression in the pallium, both xTbr1 and xEomes are expressed in a few dispersed cells in the subpallium, which may represent immigrant cells of pallial origin, because these genes are not found in the subpallial proliferating cells. On the other hand, during development xEmx1 is expressed in a large part of the pallium (proliferating and postmitotic cells) except for an area adjacent to the pallio‐subpallial boundary, where xEmx1 is observed only in some mantle cells. This pallial area poor in xEmx1 expression and poor in expression of the subpallial gene xDll4, but expressing the pallial marker genes xTbr1 and xEomes, appears to represent the amphibian ventral pallium, comparable to that described in other vertebrates (Puelles et al. [2000] J. Comp. Neurol. 424:409–438). In the adult frog, the ventral pallium appears to include the rostral part of the lateral amygdalar nucleus as well as a large part of the medial amygdalar nucleus (as defined by Marín et al. [1998] J. Comp. Neurol. 392:285–312). In contrast, the caudal part of the previously termed lateral amygdalar nucleus shows strong xEmx1 expression and may be a lateral pallial derivative. The possible homology of these amphibian amygdalar nuclei is discussed. Finally, expression of xTbr1, xEomes, and xEmx1 is observed in the mitral cell layer of the olfactory bulb from early developmental stages, further supporting that this structure is a pallial derivative. J. Comp. Neurol. 474:562–577, 2004. © 2004 Wiley‐Liss, Inc.
The temporospatial expression of peripheral myelin protein 22 at the developing blood‐nerve and blood‐brain barriers
Authors: Roux Kyle J. , Amici Stephanie A. , Notterpek Lucia 
Published: May 2004

AbstractPeripheral myelin protein 22 (PMP22), also known as growth arrest‐specific gene 3 (gas3), is a tetraspan membrane protein whose misexpression is associated with demyelinating peripheral neuropathies. Although the function of PMP22 in Schwann cells is unknown, the protein is found at intercellular junctions of various epithelia and endothelia. To begin to elucidate the role of PMP22 at cell junctions, we examined the temporal expression and protein localization during development and maturation of the rat blood‐nerve barrier (BNB) and blood‐brain barrier (BBB). Developing and adult rat sciatic nerves and brains were coimmunostained for PMP22 and known junctional proteins including zonula occludens‐1 (ZO‐1), occludin, and claudin‐5. Prior to the maturation of the BNB and BBB and detection of the tight junction protein occludin, PMP22 is present at ZO‐1 positive endothelial junctions of the sciatic nerve and brain cortex. The subcellular localization of PMP22 in cultured brain endothelia was confirmed by internalization with ZO‐1 after EGTA‐induced disruption of cell junctions. In choroid epithelia, PMP22 is detected along with occludin and ZO‐1 as early as embryonic day 15 (E15). In agreement, PMP22 message is elevated in P1 rat brain microvasculature and choroid epithelia, compared with total cortex. Additionally, neuroepithelial cell junctions in the embryonic rat brain are immunoreactive for PMP22, ZO‐1, and β‐catenin but not occludin. Together, these studies identify PMP22 as an early constituent of intercellular junctions in the developing and mature rat BNB and BBB. J. Comp. Neurol. 474:578–588, 2004. © 2004 Wiley‐Liss, Inc.
Localization of the GABAB receptor 1a/b subunit relative to glutamatergic synapses in the dorsal cochlear nucleus of the rat
Authors: Luján Rafael , Shigemoto Ryuichi , Kulik Akos , Juiz José M. 
Published: May 2004

AbstractMetabotropic γ‐aminobutyric acid receptors (GABAB) are involved in pre‐ and postsynaptic inhibitory effects upon auditory neurons and have been implicated in different aspects of acoustic information processing. To understand better the mechanisms by which GABAB receptors mediate their inhibitory effects, we used pre‐embedding immunocytochemical techniques combined with quantification of immunogold particles to reveal the precise subcellular distribution of the GABAB1 subunit in the rat dorsal cochlear nucleus. At the light microscopic level, GABAB1 was detected in all divisions of the cochlear complex. The most intense immunoreactivity for GABAB1 was found in the dorsal cochlear nucleus, whereas immunoreactivity in the anteroventral and posteroventral cochlear nuclei was very low. In the dorsal cochlear nucleus, a punctate labeling was observed in the superficial (molecular and fusiform cell) layers. At the electron microscopic level, GABAB1 was found at both post‐ and presynaptic locations. Postsynaptically, GABAB1 was localized mainly in the dendritic spines of presumed fusiform cells. Quantitative immunogold immunocytochemistry revealed that the highest concentration of GABAB1 in the plasma membrane was in dendritic spines, followed by dendritic shafts and somata. Thus, the most intense immunoreactivity for GABAB1 was observed in dendritic spines with a high density of immunogold particles at extrasynaptic sites, peaking around 300 nm from glutamatergic synapses. This is in contrast to GABAergic synapses, in which GABAB1 was only occasionally found. Presynaptically, receptor immunoreactivity was detected primarily in axospinous endings, probably from granule cells, in both the active zone and extrasynaptic sites. The localization of GABAB1 relative to synaptic sites in the DCN suggests a role for the receptor in the regulation of dendritic excitability and excitatory inputs. J. Comp. Neurol. 475:36–46, 2004. © 2004 Wiley‐Liss, Inc.
Voltammetric Oxidation of Drugs of Abuse III. Heroin and Metabolites
Authors: Garrido J. M. P. J. , Delerue‐Matos C. , Borges F. , Macedo T. R. A. , Oliveira‐Brett A. M. 
Published: May 2004

AbstractThe oxidative behavior of heroin in aqueous solution is reported. In order to identify its oxidation peaks, several metabolites, 6‐monoacetylmorphine, 3‐monoacetylmorphine and norheroin, were synthesized and their electrochemical behavior studied using differential pulse voltammetry. The anodic waves observed for heroin correspond to the oxidation of the tertiary amine group and its follow‐up product (secondary amine), and to the oxidation of the phenolic group obtained from hydrolysis, at alkaline pHs, of the 3‐acetyl group. The results enabled a new oxidative mechanism for heroin to be proposed in which a secondary amine, norheroin, and an aldehyde are obtained. The voltammetric behavior of 6‐monoacetylmorphine and morphine was found to be similar demonstrating that the presence of an acetyl substituent on the 6‐hydroxy group does not have a relevant influence on the peak potential of the wave resulting from oxidation of the 3‐phenolic group.
Synthesis and properties of novel pyrazolopyrimidine derivatives containing sulfur atom
Authors: Wang Hong‐Qing , Ding Ming‐Wu , Liu Zhao‐Jie 
Published: May 2004

AbstractA series of new pyrazolopyrimidine derivatives containing sulfur atom 5 has been designed and synthesized by treatment of carbodiimide 3, which came from iminophosphorane 2 undergoing a aza‐Wittig reaction with phenyl ioscyanate, with alkylamine. The structures of compounds 5 were confirmed by 1H NMR, IR, EI‐mass spectroscopy, and elemental analysis. The results of preliminary bioassay indicate that most compounds 5 exhibit an inhibition effect against Cercospora beticola, Botryosphaeria berengeriana, and Pellicularia sasakii, and compound 5g shows 91.2% inhibitory rate to root of rape and the other less than 50% at 100 mg/l. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:333–337, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20024