bluuebunny/crossref_metadata_2025 huggingface dataset:
Why should I be generous when I have valued and accessible alternatives? Alternative exchange partners and OCB
Authors: Thau Stefan , Bennett Rebecca J. , Stahlberg Dagmar , Werner Jon M.
Published: July 2004

An Erratum has been published for this article in Journal of Organizational Behavior 26(7) 2005, 873.

Previous research on the relationship between alternative employment opportunities and cooperation has neglected the distinction between evaluations and restrictions. Thus, one cannot analyze the relationship between attractiveness of alternative employment opportunities and organizational citizenship behaviors (OCB) under different levels of perceived ease of finding alternative employment. In a pilot study with N = 149 German employees, we confirm the proposed distinction with confirmatory factor analyses. Based on power‐dependence theory and rational choice models, we predict that under high ease the relationship between attractiveness and OCB should be more strongly negative than under conditions of low ease. In addition, we hypothesize that the interaction between attractiveness and ease should be greater for OCB than for task performance because task performance is exchanged in a relationship with an enforceable, binding contract, while OCB is voluntarily. Results from moderated multiple regression analysis on N = 86 German professional–supervisor dyads support our prediction for a negative relationship between attractiveness and OCB under high ease. Under low ease, we find a positive relationship between attractiveness and OCB. Moreover, there was no relationship with the interaction and task performance. Implications of the findings both for extra‐role and job mobility theory formation and research are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Interactive effects of impression management and organizational politics on job performance
Authors: Zivnuska Suzanne , Kacmar K. Michele , Witt L. A. , Carlson Dawn S. , Bratton Virginia K.
Published: July 2004

The purpose of this research was to explore the interactive effect of organizational politics and impression management on supervisor ratings of employee performance. We hypothesized that the negative relationship between organizational politics and supervisor‐rated performance is weaker among employees who are high in impression management than among those low in impression management. Data were collected from a matched sample of 112 white‐collar employees and their supervisors. Results indicated that the interaction of organizational politics and impression management explained a significant incremental amount of variance in supervisor ratings of employee performance. These findings demonstrated that the extent to which an individual engaged in impression management in a non‐political atmosphere may have been a key component to receiving favorable performance ratings. Copyright © 2004 John Wiley & Sons, Ltd.
Cover Picture: Macromol. Biosci. 7/2004
Authors: Chan‐Park Mary B. , Zhu Ai P. , Shen Jin Y. , Fan Ai L.
Published: July 2004

Cover: The picture on the cover presents the high aspect ratio microstructures (100 m high‐ 10 m wide‐ wall) made by photolithography using biodegradable diacrylated PCL‐b‐PEO‐b‐PCL triblock copolymer. The triblock copolymers were prepared in molecular weights of a few kilodaltons via the anionic ring‐opening polymerization. And such micro‐patterned scaffold will find many applications in tissue engineering.

Further details can be found in the full paper by M. B. Chan‐Park*, A. P. Zhu, J. Y. Shen, A. L. Fan on page 665.
UV‐Induced Cross‐Linking of Poly(ethylene oxide) in Aqueous Solution
Authors: Doycheva Maria , Petrova Elissaveta , Stamenova Rayna , Tsvetanov Christo , Riess Gerard
Published: July 2004

Summary: Hydrogels of high‐molecular‐weight poly(ethylene oxide) (PEO) have been obtained in situ by applying a very simple procedure that involves UV cross‐linking of PEO in aqueous solution. The efficiency of the photoactivated cross‐linking of thin layers of PEO in aqueous solution in the presence of (4‐benzoylbenzyl) trimethylammonium chloride as a photoinitiator has been determined at room temperature and in a frozen state (−25 °C). It was found that the efficiency varies with the concentration of PEO solution, the molecular weight of PEO, and especially with the temperature. When the UV cross‐linking was performed in the frozen state, porous hydrogels with very high yield of gel fraction (above 90%) and high cross‐linking density were obtained. After drying the hydrogels, films of 50–150 μm thickness were prepared. The films swell extremely fast in water and act as asymmetric membranes.

SEM of a dried PEO hydrogel obtained by UV cross‐linking of an aqueous solution at room temperature.

magnified image

SEM of a dried PEO hydrogel obtained by UV cross‐linking of an aqueous solution at room temperature.
Potential theoretic methods for the hyperbolic Maxwell system in rough cylinders
Authors: Mitrea Dorina
Published: July 2004

This paper is concerned with the solvability of the hyperbolic Maxwell system in Lipschitz cylinders via integral methods. By means of the Laplace transform, the original hyperbolic Maxwell system is reduced to a family of stationary Maxwell equations indexed by ω, the Laplace variable. The crux of the matter is establishing how all relevant constants in the main estimates for this family of Maxwell equations depend on ω. Among other things, appropriate norms and weighted Sobolev spaces are considered so that the integral equation method works. The solution is expressed in terms of retarded potentials. Copyright © 2004 John Wiley & Sons, Ltd.
1H and 13C spectral assignment of 2(1H)‐pyridone derivatives
Authors: Molero Dolores , Suárez Margarita , Martínez‐Álvarez Roberto , Verdecia Yamila , Martín Nazario , Seoane Carlos , Ochoa Estael
Published: July 2004

1H and 13C NMR spectroscopic data for 4‐aryl‐3,4‐dihydro‐6‐methyl‐2(1H)pyridone derivatives were fully assigned by a combination of one‐ and two‐ dimensional experiments (DEPT, HMBC, HMQC, COSY, NOE). Copyright © 2004 John Wiley & Sons, Ltd.
Complete 1H and 13C NMR assignments for two new monodesmoside saponins from Pentaclethra macroloba (Willd.) Kuntze
Authors: Viana Francisco Arnaldo , Pouliquen Yvone Brígido M. , Andrade‐Neto Manoel , Santiago Gilvandete Maria P. , Pessoa Otília Deusdênia L. , Rodrigues‐Filho Edson , Braz‐Filho Raimundo
Published: July 2004

A detailed NMR study and full assignments of the 1H and 13C spectral data for two novel triterpenoid saponins isolated from the stem bark of Pentaclethra macroloba (Willd.) Kuntze are described. Their structures were established using a combination of 1D and 2D NMR techniques including 1H,1H‐COSY, TOCSY, NOESY, gs‐HMQC and gs‐HMBC, and also electrospray ionization mass spectrometry and chemical methods. The structures were established as 3β‐O‐{[O‐β‐D‐glucopyranosyl‐(1→2)‐O‐β‐D‐glucopyranosyl‐(1→4)‐O‐β‐D‐glucopyranosyl‐(1→3)‐O‐α‐L‐rhamnopyranosyl‐(1→2)]‐[O‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐glucopyranosyl‐(1→4)]}‐α‐L‐arabinopyranosylhederagenin (1) and 3β‐O‐{[O‐β‐D‐glucopyranosyl‐(1→2)‐O‐β‐D‐glucopyranosyl‐(1→4)‐O‐β‐D‐glucopyranosyl‐(1→3)‐O‐α‐L‐rhamnopyranosyl‐(1→2)]‐[O‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐glucopyranosyl‐(1→4)]}‐α‐L‐arabinopyranosyloleanolic acid (2). Copyright © 2004 John Wiley & Sons, Ltd.
Target tissue influences the peripheral trajectory of mouse primary sensory olfactory axons
Authors: Storan Melonie J. , Key Brian
Published: July 2004

Primary olfactory neurons situated in the nasal septum project axons within fascicles along a highly stereotypical trajectory en route to the olfactory bulb. The ventral fascicles make a distinct dorsovental turn at the rear of the septum so as to reach the olfactory bulb. In the present study we have used a brain and nasal septum coculture system to examine the role of target tissue on the peripheral trajectory of olfactory sensory axons. In cultures of isolated embryonic nasal septa, olfactory axons form numerous parallel fascicles that project caudally in the submucosa, as they do in vivo. The ventral axon fascicles in the septum, however, often fail to turn, and do not project dorsally towards the roof of the nasal cavity. The presence of olfactory bulb, cortical, or tectal tissue apposed to the caudal end of the septum rescued this phenotype, causing the ventral fascicles to follow a normal in vivo‐like trajectory. Ectopic placements of the explants revealed that brain tissue is not tropic for olfactory axons but appears to maintain the peripheral trajectory of growing axons in the nasal septum. Although primary olfactory axons are able to penetrate into olfactory bulb in vitro, they only superficially enter cortical tissue, whereas they do not grow into tectal explants. The ability of axons to differentially grow into different brain regions was shown to be unrelated to the migratory behavior of olfactory ensheathing cells, indicating that olfactory axons are directly responsive to guidance cues in the brain. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
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

We 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

Edelsteine 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

Newton 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

Das 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

Schnelle 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

Einzelne 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

Mehr 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

Kleine 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

Kohlenstoff‐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

Elektronische 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

Vor 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

Häufig 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

Nach 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.
Eine Sekunde bitte
Authors: Heering Peter
Published: July 2004

Die Zeit gehört zu den physikalischen Größen, die bereits sehr früh gemessen wurden. Die Definition ihrer Basiseinheit Sekunde sowie die messtechnischen Realisierung ihrer präzisen Bestimmung zeigt zugleich auch, welche Entwicklung die Physik genommen hat.
Ein Forscher ohne Angst vorm Vakuum
Authors: Loos Andreas
Published: July 2004

Mit 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

Bei 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

An 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

We 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

In 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

In 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

Proteomic 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

The 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

Reaction 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

In 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

Here 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
Unconventional interactions between water and heterocyclic nitrogens in protein structures
Authors: Stollar Elliott J. , Gelpí Jose Luis , Velankar Sameer , Golovin Adel , Orozco Modesto , Luisi Ben F.
Published: July 2004

We report an unusual interaction in which a water molecule approaches the heterocyclic nitrogen of tryptophan and histidine along an axis that is roughly perpendicular to the aromatic plane of the side chain. The interaction is distinct from the well‐known conventional aromatic hydrogen‐bond, and it occurs at roughly the same frequency in protein structures. Calculations indicate that the water–indole interaction is favorable energetically, and we find several cases in which such contacts are conserved among structural orthologs. The indole–water interaction links side chains and peptide backbone in turn regions, connects the side chains in β‐sheets, and bridges secondary elements from different domains. We suggest that the water–indole interaction can be indirectly responsible for the quenching of tryptophan fluorescence that is observed in the folding of homeodomains and, possibly, many other proteins. We also observe a similar interaction between water and the imidazole nitrogens of the histidine side chain. Taken together, these observations suggest that the unconventional water–indole and water–imidazole interactions provide a small but favorable contribution to protein structures. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Measles virus receptors: SLAM and CD46
Authors: Dhiman Neelam , Jacobson Robert M. , Poland Gregory A.
Published: July 2004

The success of vaccination against measles in developed countries has significantly reduced the incidence of measles‐related morbidity and mortality. However, measles is still the leading cause of mortality in children from underdeveloped countries due to low vaccination coverage, high transmissibility of the measles virus as well as primary and secondary vaccine failure. As with any viral disease, the identification of the host molecule to which the measles virus binds and gains entry into the host cell is a major step in understanding the molecular pathology of the disease. Two cell surface receptors, CD46 and signaling lymphocyte‐activation molecule (SLAM), have been identified as measles virus receptors. CD46 is ubiquitously expressed on all nucleated cells and acts as a receptor for the Edmonston strain and all vaccine strains derived from it. SLAM is selectively expressed on some T and B cells and is utilised by the Edmonston strain and wild‐type strains that cannot use CD46 for cell entry. Understanding the structural and functional variations in measles virus receptors with regard to host response can facilitate the development of new vaccines as well as provide new insights into measles virus tropism and pathogenesis and, importantly, into possible mechanisms for vaccine non‐response. Our review focuses on the structure of measles virus receptors, measles virus receptor function, isoforms and polymorphic forms. Copyright © 2004 John Wiley & Sons, Ltd.
Enterovirus uveitis
Authors: Lashkevich Vasilii A. , Koroleva Galina A. , Lukashev Alexander N. , Denisova Ekaterina V. , Katargina Ludmila A.
Published: July 2004

Enterovirus uveitis (EU) is a new infant eye disease that was first observed in 1980. Three distinct subtypes of human echoviruses, EV19/K, EV11/A and EV11/B, caused five hospital outbreaks of EU in different Siberian cities in 1980–1989, affecting approximately 750 children, predominantly below 1 year of age. Sporadic EU cases were also retrospectively diagnosed in other regions of Russia and in different countries of the Former Soviet Union. The illness was characterised by rapid iris destruction and severe complications, including cataract and glaucoma. The disease has been a subject of intensive studies and was reproduced in lower primates after intraocular inoculation of isolated enterovirus strains. Importantly, prototype EV11 and EV19 strains did not induce notable disease in experimental monkeys. Some of the EU‐causing strains were shown to be similar phylogenetically and in their pathogenetic properties to the enterovirus strains associated with multisystem hemorrhagic disease of newborns. In this review we present a summary of the vast epidemiological, virological, clinical and experimental data on this new form of ophthalmic infection. Copyright © 2004 John Wiley & Sons, Ltd.
Prospects of HIV‐1 entry inhibitors as novel therapeutics
Authors: Pierson Theodore C. , Doms Robert W. , Pöhlmann Stefan
Published: July 2004

A great deal of progress has been made in understanding the mechanism of human immunodeficiency virus entry into target cells. Landmark discoveries such as the identification of viral coreceptors and the structure of a portion of the viral envelope protein (Env) bound to its receptor provided important insight into how Env mediates fusion of the viral and cellular membranes. This knowledge has been successfully applied to the development of inhibitors that target discrete steps of the entry process. Some of these compounds efficiently block HIV‐1 replication in vitro and are currently being evaluated in clinical trials. In this review, we will introduce the challenges of antiviral therapy and highlight the need for novel therapeutics, such as entry inhibitors, to complement current antiviral regimens. The mechanism by which Env mediates HIV‐1 entry and the therapeutic potential of small molecule inhibitors of this dynamic process will be discussed in detail. Copyright © 2004 John Wiley & Sons, Ltd.
Misperceptions of basic dynamics: the case of renewable resource management
Authors: Moxnes Erling
Published: July 2004

Previous laboratory experiments, using quite complex resource simulators, suggest that renewable resources are over‐utilised because of a general tendency for people to systematically misperceive the dynamics of bioeconomic systems. Here, similar experiments with simpliﬁed simulators involving the management of reindeer rangelands are carried out. Sufﬁcient information is given for the subjects to construct perfect mental models. Misperceptions persist for a simulator containing only the basic building block of all dynamic systems: one stock and two ﬂows. Results deteriorate in a second treatment where a two‐stock model is used. Compared to earlier studies using questionnaires, where subjects do not beneﬁt from repeated outcome feedback, the experiments show that, even in these simple systems, information feedback is not sufﬁcient to make up for misperceptions. Simulations are used to test two hypothesised decision rules: the optimal policy is rejected; a simple feedback rule is not. Altogether, the experiment and the simulations provide both a motivation for and an introduction to studies of system dynamics. Copyright © 2004 John Wiley & Sons, Ltd.
The dynamics of water scarcity on irrigated landscapes: Mazarrón and Aguilas in south‐eastern Spain
Authors: Fernández Julia Martínez , Selma Miguel Angel Esteve
Published: July 2004

The new irrigated lands of Mazarrón and Aguilas, south‐east Spain, have led to the overexploitation of local aquifers and to seawater intrusion, water salinization and to declining water tables. This paper discusses a dynamic model developed to analyse the key socio‐economic and environmental factors driving the whole system. The New Irrigated Lands dynamic model includes ﬁve sectors: Irrigated Lands, Proﬁtability, Available Space, Water Resources and Pollution. The dynamic model simulates the environmental effects regarding water consumption by reference to aquifer levels, natural outﬂows through springs, piezometric levels and aquifer water salinity. The exploration of scenarios shows that current policies based on the increase in water resources do not eliminate the water deﬁcit problem because the feedback loops of the system lead to a further increase in irrigated land and continuation of the water deﬁcit. This demonstrates highly counter‐intuitive behaviour. This article constitutes a contribution to the analysis of intensive irrigated lands and water management in Spain, which is mostly lacking a systemic and dynamic approach. Copyright © 2004 John Wiley & Sons, Ltd.
A scoping and consensus building model of a toxic blue‐green algae bloom
Authors: Arquitt Steven , Johnstone Ron
Published: July 2004

Nuisance blooms of Lyngbya majuscula have been occurring with increasing frequency in tropical coastal waters around the world. Outbreaks of this cyanobacterium (blue‐green algae) threaten water quality, coastal ecosystems, and can be harmful in instances of human contact. While scientiﬁc and popular theories abound regarding Lyngbya bloom initiation and growth, a clear research agenda has not emerged. This article offers a scoping and consensus building model for the development of research directions. The model is based on the hypothesis that Lyngbya is iron limited and that blooms are initiated and perpetuated in response to increased bioavailable iron concentrations. Interacting model sectors for Lyngbya, bioavailable iron, dissolved oxygen, and seagrass have been developed. Simulations show that the occurrence of Lyngbya bloom is sensitive to a number of uncertain parameters and model structures, including inﬂows and decay times of organically complexed iron, Lyngbya maximum growth rate and half‐saturation constant for bioavailable iron, and bioturbation. Development of the ﬁrst stage scoping model is reported here, as are simulation results that are instrumental in setting priorities for empirical investigations and future simulation‐based research. It is expected that this model, after additional empirical work is completed, will lead to research and management models that will help set policy for community response to Lyngbya blooms. Copyright © 2004 John Wiley & Sons, Ltd.
Environmental and resource systems: Editors' introduction
Authors: Cavana Robert Y. , Ford Andrew
Published: July 2004

This paper provides an introduction to the special issue on environmental and resource systems. The quantity and quality of previous system dynamics publications related to environmental and resource systems are brieﬂy outlined. The background to the special issue is provided, together with a summary and comparison of the ﬁve papers and models in the issue. The papers relate to forestry in Indonesia, irrigated lands in Spain, renewable resource management in Norway, wildlife management in USA and blue‐green algae bloom in the coastal waters of Australia. Copyright © 2004 John Wiley & Sons, Ltd.
Cannabinoid CB2 receptors are expressed by perivascular microglial cells in the human brain: An immunohistochemical study
Authors: Núñez Estefanía , Benito Cristina , Pazos M. Ruth , Barbachano Antonio , Fajardo Otto , González Sara , Tolón Rosa M. , Romero Julián
Published: July 2004

Two types of cannabinoid receptors have been characterized so far, CB1 and CB2. While CB1 receptors are present both in the CNS and in the periphery, CB2 receptors showed an almost exclusive distribution within the immune system. We now report that CB2 receptors are present in a specific microglial cell type of the human cerebellum. Thus, we have performed immunohistochemical analysis of tissue sections of white matter areas of the human cerebellum and detected the presence of CB2 receptors in perivascular microglial cells. These findings match with the well‐known immunomodulatory role of CB2 receptors and open new perspectives on the possible role that these receptors may play in pathophysiological events. Synapse 53:208–213, 2004. © 2004 Wiley‐Liss, Inc.
Characterization of iron‐gall inks in historical manuscripts and music compositions using x‐ray fluorescence spectrometry
Authors: Hahn O. , Malzer W. , Kanngiesser B. , Beckhoff B.
Published: July 2004

The qualitative and quantitative investigation of historical iron‐gall inks using micro‐XRF spectrometry is a suitable method for analyzing composition fingerprints of different ink types. The quantitative analysis is based on a model that takes into account the inhomogeneity and the layer structure of archaeometric samples. Starting from these composition fingerprints, it is possible to characterize distinguishable inks of one artist to classify different chronological ink types and, further, to date unknown fragments that have not so far been integrated into the lifework of an artist. The first qualitative and quantitative investigations of the manuscript ‘Faust I and II’ and of the music composition ‘The Magic Flute’ demonstrate impressively the identification of J. W. v. Goethe's and W. A. Mozart's artistic work with modern scientific methods. Further investigations on A. v. Arnim's manuscript ‘Studien zu Naturwissenschaften’ provide evidence that the diversity of various degradation mechanisms of iron‐gall inks could be mainly caused by different inorganic compositions. Copyright © 2004 John Wiley & Sons, Ltd.
1‐Hydroxy monocyclic carotenoid 3,4‐dehydrogenase from a marine bacterium that produces myxol
Authors: Teramoto Maki , Rählert Nina , Misawa Norihiko , Sandmann Gerhard
Published: July 2004

A crtD (1‐HO carotenoid 3,4‐dehydrogenase gene) homolog from marine bacterium strain P99‐3 included in the gene cluster for the biosynthesis of myxol (3′,4′‐didehydro‐1′,2′‐dihydro‐β,ψ‐carotene‐3,1′,2′‐triol) was functionally identified. The P99‐3 CrtD was phylogenetically distant from the other CrtDs. A catalytic feature was its high activity for the monocyclic carotenoid conversion: 1′‐HO‐torulene (3′,4′‐didehydro‐1′,2′‐dihydro‐β,ψ‐caroten‐1′‐ol) was prominently formed from 1′‐HO‐γ‐carotene (1′,2′‐dihydro‐β,ψ‐caroten‐1′‐ol) in Escherichia coli with P99‐3 CrtD, indicating that this enzyme has been highly adapted to myxol biosynthesis. This unique type of crtD is a valuable tool for obtaining 1′‐HO‐3′,4′‐didehydro monocyclic carotenoids in a heterologous carotenoid production system.
Temperature and cryoprotectant influence secondary quinone binding position in bacterial reaction centers
Authors: Pokkuluri P.Raj , Laible Philip D , Crawford Adam E , Mayfield Joy F , Yousef Mohammed A , Ginell Stephan L , Hanson Deborah K , Schiffer Marianne
Published: July 2004

We have determined the first de novo position of the secondary quinone QB in the Rhodobacter sphaeroides reaction center (RC) using phases derived by the single wavelength anomalous dispersion method from crystals with selenomethionine substitution. We found that in frozen RC crystals, QB occupies primarily the proximal binding site. In contrast, our room temperature structure showed that QB is largely in the distal position. Both data sets were collected in dark‐adapted conditions. We estimate that the occupancy of the QB site is 80% with a proximal: distal ratio of 4:1 in frozen RC crystals. We could not separate the effect of freezing from the effect of the cryoprotectants ethylene glycol or glycerol. These results could have far‐reaching implications in structure/function studies of electron transfer in the acceptor quinone complex because the above are the most commonly used cryoprotectants in spectroscopic experiments.