bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emergence and Composition of Trichoptera from Karst Habitats, Plitvice Lakes Region, Croatia
Authors: Previšić Ana , Kerovec Mladen , Kučinić Mladen 
Published: February 2007

AbstractAdult Trichoptera were observed at the Plitvice Lakes, Croatia during two years (2000 and 2001) using pyramid‐type emergence traps. A total of 1350 individuals and 37 species were collected. Throughout the study, the emergence patterns showed only minor variations regarding differences in particular habitats. During 2000 most species emerged in June, and in 2001 in May. The complete emergence period is shown for all collected species and studied in detail for abundant species. Excluding Allogamus uncatus, all abundant species emerged in summer, with most exhibiting a long emergence period. Rhyacophila fasciata had the longest emergence period in both years of the study and also showed winter activity. Trichopteran diversity and equitability were calculated and trophic relationships of the collected species were identified for each sampling site in order to obtain better insight into trichopteran community structure. Results indicated that the trichopteran community could be grouped according to travertine barriers and stream habitat types. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Data Reduction Exercise to Detect Threshold Samples for Regression Models to Predict Key Water Variables
Authors: Håkanson Lars 
Published: February 2007

AbstractInherent uncertainties in empirical data limit our understanding of interrelationships among variables and constrain our possibilities to identify critical thresholds as well as our possibilities to develop practically useful predictive models for water management. This work concerns key water variables for water management and the first aim is to utilize a very comprehensive set of data set for Ringkobing Fjord, Denmark. The paper first presents the methods and data used, then a reference regression for chlorophyll, coefficients of variation (CV = SD/MV; MV = mean value; SD = standard deviation) for a variety of water variables and how these CV‐values influence n, the number of data used to determine coastal area characteristic mean or median values (note that the interest here is not on the conditions in sampling bottle but on the conditions in entire coastal areas, the ecosystem perspective). The main part of the work presents a data reduction exercise including a definition of an error function where the focus is on “large N”, i.e., the number of data in a regression. The results are summarized in a diagram relating the error in the regression to different water variables with different inherent CVs in rivers, lakes and coastal areas. Given the inherently high CV‐values of many of these water variables, more samples than generally taken in most regular monitoring programs are needed if scientific unassailable conclusions are to be made concerning interrelationships among the variables and to produce scientifically meaningful information to detect critical ecosystem changes and threshold values. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oxidized phosphatidylcholine is a marker for neuroinflammation in multiple sclerosis brain
Authors: Qin J. , Goswami R. , Balabanov R. , Dawson G. 
Published: February 2007

AbstractMultiple sclerosis (MS) is a common autoimmune neurodegenerative disease of unknown cause, which results in inflammation and plaques of demyelination in brain and eventual axonal degeneration. We report the novel presence of oxidized phosphatidylcholine [1‐palmitoyl‐2‐(5′‐oxo)valeryl‐sn‐glycero‐3‐phosphorylcholine (POVPC)], a lipid associated with inflammatory diseases such as atherosclerosis and lung disease, in the brain of MS patients. The OxPC epitope was detected by Western blotting with the E06 monoclonal antibody. E06‐positive lipid was present in the highest amounts in MS plaques, which also showed evidence of low‐molecular‐weight (15‐kDa) OxPC‐modified protein. E06 reactivity did not change with post‐mortem interval, and E06‐positive lipids were largely absent from control tissue. We then used a second monoclonal antibody (AB1‐2, which recognizes the E06/T15 idiotype and therefore detects the presence of antibody to OxPC) to show that MS brain samples were strongly positive for the 50‐kDa antibody heavy chain. We also showed that isoelectric focussing of the oligoclonal IgG characteristic of MS revealed some immunoglobulin bands that Western blotted with the AB1‐2 antibody. Spinal cords from mice induced to undergo experimental allergic encephalomyelitis (EAE) also showed strong AB1‐2 reactivity by both immunocytochemistry and Western blot analysis. We therefore conclude that we can detect both OxPC and 15‐kDa protein modified by OxPC and the antibody to the antibody to OxPC (antiidiotype) in pathological tissue and suggest that this could play a role in the progression of MS. © 2007 Wiley‐Liss, Inc.
Pyruvate recycling in cultured neurons from cerebellum
Authors: Olstad Elisabeth , Olsen Grethe M. , Qu Hong , Sonnewald Ursula 
Published: February 2007

AbstractPyruvate recycling is a pathway for complete oxidation of glutamate. The cellular location and the physiological significance of such recycling has been debated during the last decade. The present study was aimed at elucidating whether recycling takes place in neuron‐enriched cultures of dissociated cerebella, consisting mainly of glutamatergic granule cells, some GABAergic neurons, and few astrocytes. These cultures and cultures of astrocytes from cerebellum were incubated in medium containing [U‐13C]glutamate, and cell extracts were analyzed by gas chromatography and mass spectrometry. Additionally, in the case of the neuron‐enriched cultures, a magnetic resonance (MR) spectrum was obtained. It could be shown that the atom percentage excess of the isotopomer representing pyruvate recycling in glutamate (M + 4) was similar for astrocytes and neuron‐enriched cultures. However, the latter showed more recycling in glutamine (synthesized in the small fraction of astrocytes) than the pure astrocyte cultures, whereas the reverse was the case for aspartate. In fact, the atom percentage excess of the isotopomer representing pyruvate recycling in glutamine was slightly but significantly higher than that in glutamate in the neuron‐enriched cultures. It can be concluded that pyruvate recycling is clearly present in neurons, and this was verified by MR spectroscopy. © 2007 Wiley‐Liss, Inc.
Adenosine inhibits voltage‐dependent Ca2+influx in cone photoreceptor terminals of the tiger salamander retina
Authors: Stella Salvatore L. , Hu Wanda D. , Vila Alejandro , Brecha Nicholas C. 
Published: February 2007

AbstractEndogenous adenosine has already been shown to inhibit transmitter release from the rod synapse by suppressing Ca2+influx through voltage‐gated Ca2+channels. However, it is not clear how adenosine modulates the cone synapse. Cone photoreceptors, like rod photoreceptors, also possess L‐type Ca2+channels that regulate the release of L‐glutamate. To assess the impact of adenosine on Ca2+influx though voltage‐gated Ca2+channels in cone terminals, whole‐cell perforated‐patch clamp recording and Ca2+imaging with fluo‐4 were used on isolated cones and salamander retinal slices. Synaptic markers (VAMP and piccolo) and activity‐dependent dye labeling revealed that tiger salamander cone terminals contain a broad, vesicle‐filled cytoplasmic extension at the base of the somatic compartment, which is unlike rod terminals that contain one or more thin axons, each terminating in a large bulbous synaptic terminal. The spatiotemporal Ca2+responses of the cone terminals do not differ significantly from the Ca2+responses of the soma or inner segment like that observed in rods. Whole‐cell recording of cone ICaand Ca2+imaging of synaptic terminals in cones demonstrate that adenosine inhibited both ICaand the depolarization‐evoked Ca2+increase in cone terminals in a dose‐dependent manner from 1 to 50 μM. These results indicate that, as in rods, adenosine's ability to suppress voltage‐dependent Ca2+channels at the cone synapse will limit the amount of L‐glutamate released. Therefore, adenosine has an inhibitory effect on L‐glutamate release at the first synapse, which likely favors elevated adenosine levels in the dark or during dark‐adapted conditions. © 2007 Wiley‐Liss, Inc.
A recombinant human IgM promotes myelin repair after a single, very low dose
Authors: Warrington Arthur E. , Bieber Allan J. , Ciric Bogoljub , Pease Larry R. , Van Keulen Virginia , Rodriguez Moses 
Published: February 2007

AbstractA recombinant human monoclonal IgM, rHIgM22, promotes the synthesis of new myelin when used to treat several animal models of demyelination. rHIgM22 binds to myelin and the surface of oligodendrocytes and accumulates at central nervous system lesions in vivo. The minimal dose of monoclonal IgM required to promote remyelination has a direct bearing on the proposed mechanism of action. A dose ranging study using rHIgM22 was performed in mice with chronic virus‐induced demyelination, a model of chronic progressive multiple sclerosis. The lowest tested dose of rHIgM22 effective at promoting spinal cord remyelination was a single 500‐ng intraperitoneal bolus injection. A time course study of spinal cord repair performed in chronically demyelinated mice revealed that remyelination plateaued by 5 weeks following treatment with rHIgM22. Two doses of rHIgM22 spaced 5 weeks apart did not increase the extent of remyelination over a single dose. The half‐life of rHIgM22 in the mouse systemic circulation was determined to be 15 hr; the human IgM serum concentration was close to zero by 48 hr following antibody administration. We propose that the specificity of rHIgM22 for myelin on living tissue targets the antibody to demyelinated lesions, initiating a long‐term reparative effect on the central nervous system. © 2007 Wiley‐Liss, Inc.
Ablation of central nervous system progenitor cells in transgenic rats using bacterial nitroreductase system
Authors: Kwak Seung P. , Malberg Jessica E. , Howland David S. , Cheng Ke‐Yi , Su Jianying , She Yin , Fennell Myles , Ghavami Afshin 
Published: February 2007

AbstractSpecific ablation of central nervous system (CNS) progenitor cells in the brain of live animals is a powerful method to determine the functions of these cells and to reveal novel avenues for the treatment of several CNS‐related disorders. To achieve this goal, we generated a line of transgenic rats expressing a bacterial enzyme, Escherichia coli nitroreductase gene (NTR), under control of the nestin promoter. In this system, NTR+ cells are selectively eliminated upon application of prodrug CB1954, through activation of programmed cell death machineries. At 5 days of age, which is a time when cerebellar development is occurring, transgenic rats bearing the nestin‐NTR/green fluorescent protein (GFP) gene are overtly normal and express NTR/GFP in neuronal stem cells, without any toxicity in these cells. The functional consequence of progenitor cell ablation was demonstrated by administering prodrug CB1954 into the cerebellum at this 5‐day time point. Stem cell ablation in these neonates resulted in sensorimotor abnormalities, cerebellar degeneration, overall reduction in cerebellar seize, and manifestation of ataxia. In adult rats, GFP expression was not seen in the hippocampal progenitor cells and seen only at very low levels in the lateral ventricles, indicating a different NTR/GFP expression pattern between neonates and adults. In addition, application of CB1954 by intraventricular delivery reduced the number of 5‐bromo‐2′‐deoxyuridine‐labeled proliferating cells in the lateral ventricle but not hippocampus of NTR/GFP rats. These findings shows that targeted expression of NTR under a specific promoter might be of significant value in addressing the function of distinct cell population in vivo. © 2007 Wiley‐Liss, Inc.
Glutamate and metabotropic glutamate receptors associated with innervation of the uterine cervix during pregnancy: Receptor antagonism inhibits c‐fos expression in rat lumbosacral spinal cord at parturition
Authors: Ghosh Chaitali , Storey‐Workley Megan , Usip Sharon , Hafemeister Jen , Miller Kenneth E. , Papka Raymond E. 
Published: February 2007

AbstractDorsal root ganglia (DRG) neurons connect the spinal cord and uterine cervix, and are activated at parturition with subsequent stimulation of secondary neurons in the spinal dorsal horn and autonomic areas. Neuropeptide neurotransmitters and receptors have been studied in these areas, but amino acid transmitters, e.g., glutamate, an excitatory neurotransmitter involved in sensory and nociceptive processing, have not been characterized. To determine if glutamate is involved in innervation of the cervix, rats were examined for markers of glutamatergic neurons in the L6‐S1 spinal cord, DRG and cervix. Metabotropic glutamate receptors mGluR5 in the spinal dorsal horn and their expression over pregnancy were examined in pregnant rats and pregnant rats treated continuously with an antagonist of mGluR5, 2‐methyl‐6‐(phenylethynyl) pyridine (MPEP). Rats were allowed to deliver pups to determine if the antagonist altered the expression of an early response gene protein, Fos, in the L6‐S1 cord. Immunohistochemistry showed glutamate‐ and vesicular glutamate transporter1 (VGluT1)‐positive fibers in the cervix, glutamate‐ and VGluT1‐expressing neurons in the DRG, some of which also exhibited retrograde tracer from cervical injections, and VGluT1 and mGluR5 immunoreactivities in the L6‐S1 spinal dorsal horns. Expression of mGluR5 receptors increased over pregnancy. Fos‐positive neurons were present among mGluR5‐immunoreactivity in the spinal dorsal horn. Parturition‐induced Fos‐positive neurons in the spinal cords were abundant in control rats, but were reduced by 70% in MPEP‐treated animals. These results suggest that glutamate is likely involved in the transmission of sensory signals, possibly pain, from the cervix to the spinal cord at parturition. © 2007 Wiley‐Liss, Inc.
Role of zinc influx via AMPA/kainate receptor activation in metabotropic glutamate receptor‐mediated calcium release
Authors: Takeda Atsushi , Fuke Sayuri , Minami Akira , Oku Naoto 
Published: February 2007

AbstractThe uptake of free zinc into CA3 pyramidal cells and its significance was examined in rat hippocampal slices with ZnAF‐2DA, a membrane‐permeable zinc indicator. Intracellular ZnAF‐2 signal in the CA3 pyramidal cell layer was increased during delivery of tetanic stimuli to the dentate granule cell layer. This increase was completely blocked in the presence of CNQX, an AMPA/kainate receptor antagonist. These results suggest that free zinc is taken up into CA3 pyramidal cells via activation of AMPA/kainate receptors. The effect of free zinc levels in the CA3 pyramidal cells on the increase in intracellular calcium via Group I metabotropic glutamate receptors was examined by regional delivery of tADA, a Group I metabotropic glutamate receptor agonist, to the stratum lucidum after blockade of AMPA/kainate receptor‐mediated calcium and zinc influx. Intracellular calcium orange signal in the CA3 pyramidal cell layer was increased by tADA, whereas intracellular ZnAF‐2 signal was not increased even in the presence of 100 μM zinc, suggesting that tADA induces calcium release from internal stores in CA3 pyramidal cells and is not involved in zinc uptake. The increase in calcium orange signal by tADA was enhanced by perfusion with pyrithione, a zinc ionophore that decreased basal ZnAF‐2 signal in the CA3 pyramidal cell layer. It was blocked by perfusion with pyrithione and zinc that increased basal ZnAF‐2 signal. The present study indicates that the increase in free calcium levels via the metabotropic glutamate receptor pathway is inversely related to free zinc levels in CA3 pyramidal cells. © 2007 Wiley‐Liss, Inc.
Mid infrared optical parametric oscillator (OPO) as a viable alternative to tissue ablation with the free electron laser (FEL)
Authors: Mackanos Mark A. , Simanovskii Dmitrii , Joos Karen M. , Schwettman H. Alan , Jansen E. Duco 
Published: February 2007

AbstractBackground and ObjectivesInvestigations with a Mark‐III free electron laser, tuned to 6.45 µm in wavelength have demonstrated minimal collateral damage and high ablation yield in ocular and neural tissues. While the use of mid‐IR light produced by the free electron laser (FEL) has shown much promise for surgical applications, further advances are limited due the high costs of its use. Further investigation and widespread clinical use of six‐micron radiation requires the development of an alternative laser source. In this research, we compared a Mark‐III FEL and an Er:YAG pumped ZGP‐OPO with respect to the effect of pulse duration on ablation efficiency and thermal damage on porcine cornea.Study Design/Materials and MethodsA five by seven grid of craters was made about the center of each cornea. Craters were made with a 60‐µm spotsize with a 500‐µm spacing. Ablation craters were made using 50 pulses per crater at approximately three times the ablation threshold (for water). Histological analysis was used to determine crater depth and thermal damage.ResultsThe average zone of thermal damage at 6.1 µm was found to be 4.1 µm for the optical parametric oscillator (OPO) and 5.4 µm for the FEL. At 6.45 µm, the damaged zone was 7.2 µm for the OPO and 7.2 µm for the FEL. At 6.73 µm, the damaged zone was 6.3 µm for the OPO and 7.6 µm±0.3 µm for the FEL.ConclusionsThe OPO caused similar or significantly less thermal damage in porcine cornea when compared with the FEL while generating significantly deeper craters. We determined that the ZGP‐OPO has much promise as a bench‐top replacement for the FEL for soft tissue ablation. Lasers Surg. Med. 39:230–236, 2007. © 2007 Wiley‐Liss, Inc.
Betrachtungen zum Löten in Gegenwart und Zukunft
Authors: Türpe M. 
Published: February 2007

AbstractIn allen Zweigen der Metall verarbeitenden Industrie und des Handwerks nimmt der Einsatz von Lötverfahren von Jahr zu Jahr zu. Der Ursprung wird vor ca. 6.000 Jahren vermutet, lange Zeit war es auf wenige Einsatzgebiete beschränkt. In der jüngsten Neuzeit zur Triebkraft von Innovationen geworden, ist es heute unverzichtbar in unterschiedlichen Anwendungsbereichen wie Mikroelektronik, Elektrotechnik, Automobilbau, Luftfahrt, Turbinenbau oder Werkzeugbau.Im vorliegenden Beitrag erfolgt zunächst eine Abgrenzung des Lötens gegenüber anderen stoffschlüssigen Verfahren. Danach werden dem Anlass entsprechende ausgewählte Entwicklungen der letzten Jahrzehnte wie Aluminiumlöten, Hochtemperaturlöten und Löten von keramischen Werkstoffen vorgestellt. Den Abschluss bildet ein Ausblick auf laufende und zukünftige Entwicklungen der Löttechnik.
Verschleißschutz für Titanbauteile
Authors: Bobzin K. , Ernst F. , Rösing J. , Rojas Y. 
Published: February 2007

AbstractDie Verwendung von Titan und seiner Legierungen hat aufgrund seiner werkstoffspezifischen Eigenschaften wie hoher Festigkeit, guter Korrosionseigenschaften und sehr hoher thermischer Belastbarkeit, in den letzten Jahrzehnten stetig zugenommen. Derzeit wird jedoch der Einsatz in tribologischen Systemen durch eine relativ niedrige Verschleißbeständigkeit eingeschränkt. Der Verschleiß an Bauteiloberflächen ist prinzipiell eine Eigenschaft, die bedingt ist durch die chemischen und physikalischen Wechselwirkungen der beteiligten Elemente sowie des auf das Bauteil wirkenden Beanspruchungskollektivs. Ausgehend von der Gesamtkomplexität eines tribologischen Problems zeigt sich die Notwendigkeit der Bereitstellung von beanspruchungsgerechten Verschleißschutzsystemen. Titanlegierungen sind im Allgemeinen nur eingeschränkt schweißbar, da eine Versprödung durch Aufnahme von Wasserstoff und Sauerstoff oberhalb von 950 °C sowie die α‐β‐Gefügeumwandlung auftreten können. Die Übertragung von etablierten Löttechniken, die zurzeit Anwendung bei Stahlwerkstoffen finden, bilden hier einen Entwicklungsansatz. Durch Auftraglöten von Hartstoffen auf Titanbauteile wird eine individuelle Optimierung ermöglicht, wobei verschiedene Hartstoffe mit kommerziellen Lotwerkstoffen kombiniert und als Pasten appliziert werden.
Zyklische Beanspruchung drahtverstärkter Verbundstrangpressprofile mit Aluminiummatrix
Authors: Weidenmann K.A. , Schwind Th. , Kerscher E. , Löhe D. 
Published: February 2007

AbstractEin innovatives Werkstoffkonzept für Leichtbaustrukturen sind durch Verbundstrangpressen hergestellte Profile auf Aluminiumbasis, in die steife und hochfeste Verstärkungselemente im Umformprozess eingebracht werden. Hierdurch sollen die mechanischen Eigenschaften verbessert und damit die Leistungsfähigkeit der Tragwerke gesteigert werden. Verbundstrangpressprofile aus der Aluminiumlegierung EN AW‐6060 mit Verstärkungselementen aus dem Federstahl 1.4310 und der Kobaltbasislegierung Haynes 25 wurden hinsichtlich der für den Einsatz entscheidenden mechanischen Eigenschaften unter bauteilnaher, d. h. zyklischer Beanspruchung untersucht. Zur Ermittlung der zyklischen Spannungs‐Dehnungs‐Kurve wurden zunächst lastkontrollierte Laststeigerungsversuche (Multiple‐Step‐Tests) bei einem Lastverhältnis von R = ‐1 durchgeführt. Aus den erarbeiteten Ergebnissen wurden mit Hilfe klassischer Werkstoffmodelle nach Morrow und Basquin Lebensdauerprognosen abgeleitet, die in anschließenden mittelspannungsfreien Dauerschwingversuchen verifiziert werden konnten. Darüber hinaus wurden licht‐ und elektronenmikroskopische Untersuchungsmethoden zur Aufklärung des Schädigungs‐ und Versagensverhaltens eingesetzt. Die Untersuchungen wurden an mehreren Probenvarianten durchgeführt, wobei Material, Konfiguration und Oberflächenbehandlung der Verstärkungselemente variiert wurden. Ziel war es, Einflüsse dieser Parameter auf das Lebensdauerverhalten zu identifizieren, um so die Werkstoffsysteme hinsichtlich des Ermüdungsverhaltens zu optimieren.
Microstructure formation in electrochemically deposited Copper thin films
Authors: Kremmer K. , Yezerska O. , Schreiber G. , Masimov M. , Klemm V. , Schneider M. , Rafaja D. 
Published: February 2007

AbstractThe influence of the electrochemical potential and deposition mode on the preferred orientation, morphology and microstructure of crystallites in electrochemically deposited (ECD) copper thin films was investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and the diffraction of back‐scattered electrons (EBSD). As a working electrode for the ECD process, thin gold layers were employed that were deposited on floating‐glass substrates in a vacuum evaporation process.With increasing negative electrochemical potential in the ECD process, the deposition mode changed from the charge transfer controlled one to the diffusion controlled one. At the highest electrochemical potentials, the copper deposition and the hydrogen release were running concurrently. The change of the deposition mode was accompanied by a change of the surface roughness of the thin films and by a change of the direction and degree of the preferred orientation of crystallites. The surface roughness of the deposited copper thin films increased with increasing electrochemical potential. Compact plate‐like crystallites with the preferred orientation {111} grew in the transport controlled deposition mode. Development of the {111} texture was supported by the {111} preferred orientation of the gold layers and by surface energy of copper, which is the lowest in the (111) plane. The diffusion controlled deposition mode was characterized by the growth of globular {110}‐oriented crystallites. The {110} texture resulted from the minimization of the anisotropic strain energy of copper via reduction of the structure defects in this deposition modus. For highest electrochemical potentials, the copper deposition run simultaneously with the development of hydrogen that resulted in growth of needle‐like crystallites with the {100} texture.