bluuebunny/crossref_metadata_2025_split huggingface dataset:
GABAergic modulation of motor‐driven behaviors in juvenileDrosophilaand evidence for a nonbehavioral role for GABA transport
Authors: Leal Sandra M. , Kumar Nitin , Neckameyer Wendi S. 
Published: July 2004

AbstractWe have identified specific GABAergic‐modulated behaviors in the juvenile stage of the fruit fly,Drosophilamelanogastervia systemic treatment of second instar larvae with the potent GABA transport inhibitor DL‐2,4‐diaminobutyric acid (DABA). DABA significantly inhibited motor‐controlled body wall and mouth hook contractions and impaired rollover activity and contractile responses to touch stimulation. The perturbations in locomotion and rollover activity were reminiscent of corresponding DABA‐induced deficits in locomotion and the righting reflex observed in adult flies. The effects were specific to these motor‐controlled behaviors, because DABA‐treated larvae responded normally in olfaction and phototaxis assays. Recovery of these behaviors was achieved by cotreatment with the vertebrate GABAAreceptor antagonist picrotoxin. Pharmacological studies performedin vitrowith plasma membrane vesicles isolated from second instar larval tissues verified the presence of high‐affinity, saturable GABA uptake mechanisms. GABA uptake was also detected in plasma membrane vesicles isolated from behaviorally quiescent stages. Competitive inhibition studies of [3H]‐GABA uptake into plasma membrane vesicles from larval and pupal tissues with either unlabeled GABA or the transport inhibitors DABA, nipecotic acid, or valproic acid, revealed differences in affinities. GABAergic‐modulation of motor behaviors is thus conserved between the larval and adult stages ofDrosophila, as well as in mammals and other vertebrate species. The pharmacological studies reveal shared conservation of GABA transport mechanisms betweenDrosophilaand mammals, and implicate the involvement of GABA and GABA transporters in regulating physiological processes distinct from neurotransmission during behaviorally quiescent stages of development. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Katzenaugen und Sternsteine: Spielwiese
Authors: Ucke Christian , Schlichting Hans‐Joachim 
Published: July 2004

AbstractEdelsteine vom Typ Chrysoberyll sind auch unter der Kurzbezeichnung Katzenauge bekannt. Im Chrysoberyll eingelagert sind feine, parallel angeordnete, metallisch glänzende Nadeln aus Rutil (Titandioxid). Auch Hohlkanäle und Risse durchziehen das Material. Lichtreflexion an diesen Einlagerungen und Kanälen erklärt das Lichtband, das dem Stein zu seinem Namen verhalf.
Kosmische Kreisel: Inertialsysteme und Gravitomagnetismus
Authors: Giulini Domenico 
Published: July 2004

AbstractNewton formulierte sein Trägheitsgesetz unter der Annahme eines globalen, absolut gültigen Inertialsystems. Dieses starre System ersetzte die Allgemeine Relativitätstheorie (ART) durch ein dynamisches Konzept lokaler, Raumzeit abhängiger Inertialsysteme. Diese Dynamisierung vormals rein kinematisch gedachter Strukturen wird durch das gravitomagnetische Feld vermittelt. Die Existenz dieses Felds verändert somit Newtonsche Vorstellungen tiefgreifend. Im Rahmen der ART ist das gravitomagnetische Feld unabdingbar. Experimentell wird seine Existenz bereits durch starke Indizienbeweise gestützt, ein direkter Nachweis steht unmittelbar bevor. habilitiert dort 1996. Aufenthalte an der �cole Normale Sup�rieure in Paris, Pennsylvania‐State University (College Park) und der Universität Zürich. Forscht auf den Gebieten der mathematischen Allgemeinen Relativitätstheorie und der Quantengravitation.
Die Quantenwelt — unbestimmt und nichtlokal?: Interpretation verschränkter Zustände
Authors: Fink Helmut 
Published: July 2004

AbstractDas aufblühende Gebiet der Quanteninformationsverarbeitung belebt die alte Frage, wie das Phänomen der quantenphysikalischen Verschränktheit zu interpretieren sei. Besonders das berühmte Gedankenexperiment von Einstein, Podolsky und Rosen rückt wieder in das Zentrum der Aufmerksamkeit, seit Laborexperimente an verschränkten Quantensystemen durchgeführt werden, deren Teile räumlich weit von einander entfernt sind. Kann ein Teil eines solchen verschränkten Systems mit Überlichtgeschwindigkeit „spüren”︁, dass an einem weit entfernten anderen Teil gemessen wird? Hinter dieser Frage steckt die Vorstellung, es gebe einen nichtlokalen Mechanismus in der Natur. Diese Vorstellung erweist sich jedoch als keineswegs zwingend und sogar als irreführend, wenn man akzeptiert, dass die Werte von Beobachtungsgrößen in Quantenzuständen objektiv unbestimmt sind. Sie entstehen erst dort, wo wirklich gemessen wird.
Mit Neutronen auf der Spur von Schrödingers Katze: Attosekunden‐Verschränkung
Authors: C.‐Dreismann C. Aris 
Published: July 2004

AbstractSchnelle Neutronen ermöglichen neue Einsichten in den inneren Aufbau kondensierter Materie: Sie können dynamische Prozesse sichtbar machen, die in wenigen hundert Attosekunden ablaufen. Auf dieser ultrakurzen Zeitskala gehen die Kerne der Wasserstoffatome in der Materie eine komplexe quantenmechanische Verschränkung mit ihren benachbarten Elektronen und Atomkernen ein. Deshalb scheinen diese Protonen beim Streuprozess teilweise zu verschwinden: Wasser zum Beispiel erscheint dann als H1, 5O anstatt H2O. Neutronen‐Compton‐Streuexperimente an der Neutronen‐Spallationsquelle ISIS und Elektronen‐Compton‐Streuexperimente in Canberra (Australien) weisen auf eine bisher unerkannte Bedeutung der Verschränkung in atomaren und molekularen Prozessen hin, etwa dem Aufbau oder Bruch chemischer Bindungen.
Auf Proteinjagd in der T‐Zelle: Einzelmolekül‐Mikroskopie
Authors: Brameshuber Mario , Mörtelmaier Manuel 
Published: July 2004

AbstractEinzelne Moleküle in lebenden Zellen mit Fluoreszenzmikroskopen zu beobachten, ist derzeit noch eine technische Herausforderung. Sie lohnt sich aber: So können erstmals die molekularen Bausteine des Lebens, etwa Proteine, bei ihren Aktivitäten direkt verfolgt werden. Das erlaubt völlig neue Einblicke in die Funktionsmechanismen biologischer Zellen. Ein interessantes Forschungsobjekt sind die T‐Zellen, die das Immunsystem steuern. Die Beobachtung einzelner Proteine kann das Rätsel lösen helfen, wie T‐Zellen gefährliche von ungefährlichen Erregern unterscheiden können. Damit Einzelmolekül‐Mikroskope routinemäßig in Biolabors eingesetzt werden können, müssen sie noch robuster, billiger und einfacher handhabbar werden.
Keine unkonventionellen Modelle für Hochtemperatur‐Supraleiter
Authors: Bernhard Christian , Boris Alexander , Keimer Bernhard 
Published: July 2004

AbstractMehr als 18 Jahre nach der Entdeckung der Hochtemperatur‐Supraleitung durch Bednorz und Müller bleibt der zugrunde liegende mikroskopische Mechanismus unklar. Es besteht durchaus kein Mangel an vorgeschlagenen theoretischen Modellen, doch ist es schwierig, sie experimentell zu überprüfen. Kürzlich ließ sich zumindest eine Klasse von unkonventionellen Modellen widerlegen [1].
Mikro‐Wassermühlen organisieren sich
Authors: Drach Volker 
Published: July 2004

AbstractKleine Rotoren an der Grenzfläche von Flüssigkeit und Luft lassen sich zu selbstorganisierten Maschinchen machen. Dies demonstrierte eine Forschergruppe um Bartosz Grzybowski von der Northwestern Universität in den USA, indem sie die etwa einen Millimeter große Rotoren magnetisch antrieben und deren hydrodynamische Wechselwirkung ausnutzten [1].
Buckypapers als Dehnungssensoren
Authors: Leute Angelika 
Published: July 2004

AbstractKohlenstoff‐Nanoröhrchen leiten elektrischen Strom wesentlich besser als Kupfer, sind zwanzigmal so zugfest wie Stahl und dabei äußerst elastisch und flexibel. Aufgrund dieser Eigenschaften gelten die nur wenige Nanometer dicken Röhrchen als aussichtsreicher Rohstoff für vielfältige technische Anwendungen — beispielsweise auch als elektromechanische Sensoren.
Transistoren aus dem Reagenzglas
Authors: Loos Andreas 
Published: July 2004

AbstractElektronische Bauteile aus einzelnen Molekülen herzustellen, ist ein Traum der Physiker (Physik in unserer Zeit 2003, 34 (6), 272). Vielleicht könnte der polyzyklische Kohlenwasserstoff Hexabenozocoronen (HBC) ein Stück weiter helfen. Ein Team um Frank Jäckel und Jürgen Rabe an der Berliner Humboldt‐Universität hat zusammen mit Kollegen des Max‐Planck‐Instituts für Polymerforschung in Mainz aus dem bräunlichen Stoff Transistoren gemixt, die gerade mal ein Molekül groß sind [1].
Optische Vorläufer nachgewiesen
Authors: Ziegler Thomas 
Published: July 2004

AbstractVor 90 Jahren entwickelten Sommerfeld und Brillouin die Theorie von Vorläuferwellen in dielektrischen Medien. Jetzt konnten zwei Physiker von der Thayer School of Engineering in New Hampshire, USA, diesen Effekt erstmals nachweisen [1].
Wenn alles auf einen Punkt zuläuft
Authors: Schlichting H. Joachim 
Published: July 2004

AbstractHäufig sieht man Kondensstreifen von Flugzeugen, die alle in dieselbe Himmelsrichtung verlaufen und am Horizont scheinbar zusammenkommen (Abbildung 1). Diese künstlichen Wolken geben einerseits Hinweise auf die meteorologischen Bedingungen in großen Höhen. Andererseits lässt sich einfach abschätzen, in welcher Höhe die Flugzeuge fliegen.
Sieben Jahre in Bern
Authors: Hentschel Ann M. 
Published: July 2004

AbstractNach gescheitertem Promotionsversuch an der Universität Zürich suchte der 22jährige Absolvent der heutigen Eidgenössischen Technischen Hochschule, Albert Einstein, sein Glück in der schweizerischen Hauptstadt Bern. Dort entstanden seine bahnbrechenden Arbeiten zur Speziellen Relativitätstheorie, Brownschen Bewegung und zur Quantentheorie.
Ein Forscher ohne Angst vorm Vakuum
Authors: Loos Andreas 
Published: July 2004

AbstractMit 30.000 Einwohnern gehörte seine Geburtsstadt zu einer der größeren Städte Deutschlands — und seine Familie zu einer der großen Familien dieser Stadt: Zwischen 1532 und 1630 trugen 19 Bürgermeister seinen Nachnamen; in den 30 Jahren davor stellte sein Geschlecht 22 Stadtkämmerer.
Sommerbraten
Authors: Vilgis Thomas 
Published: July 2004

AbstractBei Sommerhitze wird stundenlanges Kochen in heißen Küchen schnell zur Pein. Deshalb sind die Möglichkeiten, während des Garens die Küche zu verlassen oder gar im Freien den Grill anzuwerfen, höchst willkommen. Welche Variante Sie auch wählen, physikalischer Sachverstand ist bei beiden Methoden angebracht, denn wenn Fleisch nicht die Aufmerksamkeit bekommt, die es verdient, geraten Braten oder Steaks schnell trocken, faserig und ungenießbar.
A peptide preconcentration approach for nano‐high‐performance liquid chromatography to diminish memory effects
Authors: Schaefer Heike , Chervet Jean‐Pierre , Bunse Christian , Joppich Cornelia , Meyer Helmut E. , Marcus Katrin 
Published: July 2004

AbstractAn advanced method has been developed for the analysis of proteolytic digests of complex protein mixtures by reversed phase high‐performance liquid chromatography coupled to mass spectrometry. The occurrence of memory effects was prevented by a parallel set of two precolumns employed for simultaneous separation and washing procedures. The system was tested extensively, and tryptic digests of three single proteins were analyzed. In addition, different solvent systems were evaluated for effective washing of the employed precolumns. Using the analytical strategy presented, a reliable identification of proteins in complex mixtures was obtained and not hampered by the occurrence of memory effects.
In vitro and in silico processes to identify differentially expressed proteins
Authors: Allet Nadia , Barrillat Nicolas , Baussant Thierry , Boiteau Celia , Botti Paolo , Bougueleret Lydie , Budin Nicolas , Canet Denis , Carraud Stéphanie , Chiappe Diego , Christmann Nicolas , Colinge Jacques , Cusin Isabelle , Dafflon Nicolas , Depresle Benoît , Fasso Irène , Frauchiger Pascal , Gaertner Hubert , Gleizes Anne , Gonzalez‐Couto Eduardo , Jeandenans Catherine , Karmime Abderrahim , Kowall Thomas , Lagache Sophie , Mahé Eve , Masselot Alexandre , Mattou Hassan , Moniatte Marc , Niknejad Anne , Paolini Marianne , Perret Frédéric , Pinaud Nicolas , Ranno Frédéric , Raimondi Sylvain , Reffas Samia , Regamey Pierre‐Olivier , Rey Pierre‐Antoine , Rodriguez‐Tomé Patricia , Rose Keith , Rossellat Gérald , Saudrais Cédric , Schmidt Camille , Villain Matteo , Zwahlen Catherine 
Published: July 2004

AbstractWe present an integrated proteomics platform designed for performing differential analyses. Since reproducible results are essential for comparative studies, we explain how we improved reproducibility at every step of our laboratory processes, e.g. by taking advantage of the powerful laboratory information management system we developed. The differential capacity of our platform is validated by detecting known markers in a real sample and by a spiking experiment. We introduce an innovative two‐dimensional (2‐D) plot for displaying identification results combined with chromatographic data. This 2‐D plot is very convenient for detecting differential proteins. We also adapt standard multivariate statistical techniques to show that peptide identification scores can be used for reliable and sensitive differential studies. The interest of the protein separation approach we generally apply is justified by numerous statistics, complemented by a comparison with a simple shotgun analysis performed on a small volume sample. By introducing an automatic integration step after mass spectrometry data identification, we are able to search numerous databases systematically, including the human genome and expressed sequence tags. Finally, we explain how rigorous data processing can be combined with the work of human experts to set high quality standards, and hence obtain reliable (false positive < 0.35%) and nonredundant protein identifications.
Identification of tumor‐associated plasma biomarkers using proteomic techniques: From mouse to human
Authors: Juan Hsueh‐Fen , Chen Jenn‐Han , Hsu Wei‐Tse , Huang Su‐Ching , Chen Shui‐Tein , Yi‐Chung Lin John , Chang Yu‐Wang , Chiang Chih‐Yin , Wen Li‐Li , Chan De‐Chuan , Liu Yao‐Chi , Chen Yu‐Ju 
Published: July 2004

AbstractIn an effort to identify tumor‐associated proteins from plasma of tumor‐bearing mice that may be used as diagnostic biomarkers, we developed a strategy that combines a tumor xenotransplantation model in nude mice with comparative proteomic technology. Five human cancer cell lines (SC‐M1, HONE‐1, CC‐M1, OECM1, GBM 8401) derived from stomach, nasopharyngeal, colon, oral and brain cancers were subcutaneously inoculated into nude mice and compared to control nude mice injected with phosphate‐buffered saline. One month later, plasma from mice inoculated with cancer cells was collected for proteomic analysis using two‐dimensional gel electrophoresis (2‐DE) and mass spectrometry (MS). Comparison of plasma 2‐DE maps from tumor‐bearing mice with those produced from control mice revealed the overexpression of several mouse acute phase proteins (APPs) such as haptoglobin. Another APP, serum amyloid A (SAA), was found only in mice bearing tumors induced by the stomach cancer cell line SC‐M1, which has not previously been demonstrated in xenotransplatation experiment. Furthermore, by using immunohistochemistry, SAA and haptoglobin were found to originate from the mouse hosts and not from the human cancer cell line donors. The protein alterations were further confirmed on patients with stomach cancers where up‐regulated levels of SAA were also observed. These results indicate that APPs may be used as nonspecific tumor‐associated serum markers. SAA in particular may serve as a potential marker for detecting stomach cancer. Taken together, the combination of the xenotransplatation model in nude mice and proteomics analysis provided a valuable impact for clinical applications in cancer diagnostics. In addition, our findings demonstrate that a panel of APPs might serve as screening biomarkers for early cancer detection.
Mining mass spectra for diagnosis and biomarker discovery of cerebral accidents
Authors: Prados Julien , Kalousis Alexandros , Sanchez Jean‐Charles , Allard Laure , Carrette Odile , Hilario Melanie 
Published: July 2004

AbstractIn this paper we try to identify potential biomarkers for early stroke diagnosis using surface‐enhanced laser desorption/ionization mass spectrometry coupled with analysis tools from machine learning and data mining. Data consist of 42 specimen samples, i.e., mass spectra divided in two big categories, stroke and control specimens. Among the stroke specimens two further categories exist that correspond to ischemic and hemorrhagic stroke; in this paper we limit our data analysis to discriminating between control and stroke specimens. We performed two suites of experiments. In the first one we simply applied a number of different machine learning algorithms; in the second one we have chosen the best performing algorithm as it was determined from the first phase and coupled it with a number of different feature selection methods. The reason for this was 2‐fold, first to establish whether feature selection can indeed improve performance, which in our case it did not seem to confirm, but more importantly to acquire a small list of potentially interesting biomarkers. Of the different methods explored the most promising one was support vector machines which gave us high levels of sensitivity and specificity. Finally, by analyzing the models constructed by support vector machines we produced a small set of 13 features that could be used as potential biomarkers, and which exhibited good performance both in terms of sensitivity, specificity and model stability.
Lessons from Kitty Hawk: From feasibility to routine clinical use for the field of proteomic pattern diagnostics
Authors: Petricoin Emanuel F. , Fishman David A. , Conrads Thomas P. , Veenstra Timothy D. , Liotta Lance A. 
Published: July 2004

AbstractProteomic pattern diagnostics is a rapidly evolving field of science. Despite the increasingly large number of laboratories reporting exciting success with this concept, recent speculation concerning reproducibility and the nature and identities of the information content of the pattern constituents have served to defocus and polarize the community. These controversies will be rendered obsolete as the field accelerates into a new realm of clinical diagnostics. This new era will see the currently dry biomarker pipeline flooded with new candidate molecules, and the mass spectrometer will continue its maturation into a dominant clinical platform. We reflect on the important lessons gleaned from the Wright brothers' attempts at controlled heavier‐than‐air flight as a model for perseverance and a view to the very near future for proteomic pattern diagnostics.
Advances in the development of common interchange standards for proteomic data
Authors: Orchard Sandra , Taylor Chris F. , Hermjakob Henning , Weimin‐Zhu  , Julian Randall K. , Apweiler Rolf 
Published: July 2004

AbstractThe generation of proteomics data is increasingly high‐throughput and high volume. Both experimental design and the technologies used to produce and subsequently analyze the data are becoming ever more complex. An increasing need for methods by which such data can be accurately described, stored and exchanged between experimenters and data repositories has been recognised. Work by the Proteomics Standards Initiative of the Human Proteome Organisation has laid the foundation for the development of standards by which experimental design can be described and data exchange facilitated. At a recent workshop in Nice, participants gathered to review the progress made to date and assist in pushing the process still further forward.
DFT study of the mechanism of nitration of toluene with nitronium
Authors: Chen Litao , Xiao Heming , Xiao Jijun 
Published: July 2004

AbstractReaction profiles of the isomeric nitration of toluene with nitronium ion were studied. Stationary points including three isomeric transition states were successfully located and characterized for the first time by employing hybrid DFT procedures at the B3LYP/6–311G** level without any restriction on the internal coordinates. Further correlation energy corrections by MP2/6–311G**//B3LYP/6–311G** were performed to evaluate the activation barrier heights. Mechanistic studies on the geometry, charge, energy and IR spectrum of the stationary points were carried out to illustrate the microscopic nitration process. A comparison of the nitrations of toluene and benzene shows that the methyl group plays dual roles in the nitration of toluene for its inductive and superconjugative effects. That is, the introduction of a methyl group creates favorable sites for the attacker and stabilizes the isomeric toluene–NO complexes. Both roles are critical to the positional selectivity. The order of the activation barrier height is para < ortho < benzene < meta. This relative reactivity order is not changed with either B3LYP/6–311G** or MP2/6–311G**//B3LYP/6–311G** calculations, although the absolute magnitude of the latter is larger. The order of the stability of complexes is p‐toluene–NO > o‐toluene–NO > m‐toluene–NO > benzene–NO. The relationship between the energy and the electron migration of NO2 group was established to elucidate the stabilization caused by the interaction between the two moieties of the complex. The vibrational shifts of tetrahedral C—N and C—H bonds suggest that the nitration of toluene may undergo the classical electrophilic substitution pathway, namely an SE2 mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
Structural transformations in organic crystals during photochemical reactions
Authors: Turowska‐Tyrk Ilona 
Published: July 2004

AbstractIn the 1980s and 1990s, x‐ray studies of the photochemical reaction course in crystals dealt with the analysis of changes in cell constants or movements of atom groups inside molecules. This review presents the results of crystallographic studies on the monitoring of the behaviour of whole molecules in organic crystals during photochemical reactions. Papers on this subject started to appear only a few years ago. The studies showed quantitatively that reactant and product molecules do not take a fixed position in a crystal during the reaction. The product molecules move smoothly to a position assumed in the pure product crystal and the reactant molecules move from a position occupied in the pure reactant crystal. Moreover, with the reaction progress the adjacent reactant molecules gradually come closer and change their mutual orientation to resemble the product. The analysis of the photoreaction kinetics in crystals is also presented. Copyright © 2004 John Wiley & Sons, Ltd.
Two‐dimensional polymer synthesis through the topochemical polymerization of alkylenediammonium muconate as a multifunctional monomer
Authors: Nagahama Sadamu , Matsumoto Akikazu 
Published: July 2004

AbstractHere we demonstrate a unique two‐dimensional polymer synthesis through topochemical polymerization via polymer crystal engineering, which is useful for controlling and designing the polymerization reactivity as well as the polymer chain and crystal structures. We have succeeded in the synthesis of a sheet polymer through the polymerization of alkylenediammonium (Z,Z)‐muconate as a multifunctional 1,3‐diene monomer in the crystalline state under the irradiation of UV and γ‐rays or upon heating in the dark. The photopolymerization reactivity of several muconates and the structural control of the obtained polymer are described. The stereochemical structure of the polymer and the polymerization mechanism are discussed on the basis of the results of IR and NMR spectroscopy, thermogravimetric measurements, and solid‐state hydrolysis for the transformation into poly(muconic acid). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3922–3929, 2004