bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Peroxisome Proliferator‐Activated Receptors in Inflammation Control
Authors: Youssef Jihan , Badr Mostafa
Published: July 2004

Peroxisome proliferator‐activated receptors (PPARs) were discovered over a decade ago, and were classified as orphan members of the nuclear receptor superfamily. To date, three PPAR subtypes have been discovered and characterized (PPARα, β/δ, γ). Different PPAR subtypes have been shown to play crucial roles in important diseases and conditions such as obesity, diabetes, atherosclerosis, cancer, and fertility. Among the most studied roles of PPARs is their involvement in inflammatory processes. Numerous studies have revealed that agonists of PPARα and PPARγ exert anti‐inflammatory effects both in vitro and in vivo. Using the carrageenan‐induced paw edema model of inflammation, a recent study in our laboratories showed that these agonists hinder the initiation phase, but not the late phase of the inflammatory process. Furthermore, in the same experimental model, we recently also observed that activation of PPARδ exerted an anti‐inflammatory effect. Despite the fact that exclusive dependence of these effects on PPARs has been questioned, the bulk of evidence suggests that all three PPAR subtypes, PPARα, δ, γ, play a significant role in controlling inflammatory responses. Whether these subtypes act via a common mechanism or are independent of each other remains to be elucidated. However, due to the intensity of research efforts in this area, it is anticipated that these efforts will result in the development of PPAR ligands as therapeutic agents for the treatment of inflammatory diseases.
Host Cell Phenotypic Variability Induced by Trypanosomatid‐Parasite‐Released Immunomodulatory Factors: Physiopathological Implications
Authors: Ouaissi Ali , Ouaissi Mehdi , Tavares Joana , Cordeiro-Da-Silva Anabela
Published: July 2004

The parasitic protozoa Trypanosoma cruzi and Leishmania sp release a variety of molecules into their mammalian hosts (ESA: excretory‐secretory products). The effects of these ESA on the host cell function may participate in the establishment of a successful infection, in which the parasite persists for a sufficient period of time to complete its life cycle. A number of regulatory components or processes originating from the parasite that control or regulate the metabolism and the growth of host cell have been identified. The purpose of the present review is to analyze some of the current data related to the parasite ESA that interfere with the host cell physiology. Special attention is given to members of conserved protein families demonstrating remarkable diversity and plasticity of function (ie, glutathione S‐transferases and related molecules; members of the trans‐sialidase and mucin family; and members of the ribosomal protein family). The identification of parasite target molecules and the elucidation of their mode of action toward the host cell represents a step forward in efforts aimed at an immunotherapeutic or pharmacological control of parasitic infection.
Epigenetic silencing of the immunoglobulin heavy-chain gene in classical Hodgkin lymphoma-derived cell lines contributes to the loss of immunoglobulin expression
Authors: Ushmorov Alexey , Ritz Olga , Hummel Michael , Leithäuser Frank , Möller Peter , Stein Harald , Wirth Thomas
Published: July 2004

Immunoglobulin production is impaired in Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) in spite of functional clonal rearrangements. The presence of “crippling” mutations in coding and regulatory regions, as well as down-regulation of B-cell-specific transcription factors, has been suggested as a potential reason for the lack of immunoglobulin (Ig) chain gene transcription. We have investigated the impact of epigenetic silencing in suppressing Ig heavy (H)-chain expression. Chromatin immunoprecipitation (ChIP) was used to analyze transcription factor binding to octamer motifs present in the IgH regulatory regions. Transcription factors were bound to these motifs in control cell lines, however, they were absent in the cHL-derived cell lines KMH2, L1236, and L428. Ectopic expression of octamer-binding transcription factor (Oct2) and/or B-cell Oct binding protein/Oct-binding factor (BOB.1/OBF.1) did not result in any measurable binding to these sites. Increased histone 3 Lysine 9 (H3-K9) methylation was observed in the promoter region of the IgH locus in L428 and L1236 cells. This is a typical feature of heterochromatic, transcriptionally silent regions. Treatment of cHL-derived cell lines with the DNA demethylating agent 5-aza-2′-deoxycytidine (5-aza-dC) partially reactivated IgH transcription and affected chromatin modifications. Our results suggest an important role of epigenetic silencing in the inhibition of IgH transcription in HRS cells. (Blood. 2004;104:3326-3334)
Methoden und Sensoren zur Überwachung von Handhabungs- und Fügeprozessen in der Mikrosystemtechnik (Methods and Sensors for the Control of Handling and Assembly Processes in Microtechnology)
Authors: Driessen Sascha , Engelmann Bastian
Published: July 2004

Der vorliegende Artikel stellt aus dem Gebiet der prozessintermittierenden Qualitätskontrolle Aspekte aus dem Bereich der Form- und Lageerkennung von Mikrobauteilen mittels faseroptischer Streifenprojektion und eine Anwendung von bildverarbeitungsgestützter Prozessüberwachung vor. Zur Thematik der klassischen Postprozessmesstechnik wird im Kontext der konfokalen Laserscanningmikroskopie eine Möglichkeit zur Erhöhung der Flexibilität des Messverfahrens auf Basis angepasster Signalauswertung dargestellt.
Messtechnische Beiträge aus der PTB zur modernen Produktionstechnik (Metrological Contributions of PTB for Modern Production Technologies)
Authors: Hasche Klaus
Published: July 2004

Das Tätigkeitsprofil der Abteilung Fertigungsmesstechnik in der PTB beinhaltet dominant metrologische Forschung und Entwicklung sowie Dienstleistungen auf dem Gebiet dimensioneller Messungen. Die Aufgaben leiten sich aus der Mission der PTB und Problemstellungen der Produktionstechnik ab. Der Beitrag geht auf die Verknüpfung von Qualität, Messtechnik und die Rückführung von Messergebnissen ein. Einige FuE-Ergebnisse werden kurz dargestellt.
Synthesis of New Chiral Aryl Diphosphite Ligands Derived from Pyranoside Backbone of Monosacharides and Their Application in Copper‐Catalyzed Asymmetric Conjugate Addition of Diethylzinc to Cyclic Enones
Authors: Wang Lailai , Li Yue‐Ming , Yip Chiu‐wing , Qiu Liqin , Zhou Zhongyuan , Chan Albert S. C.
Published: August 2004

New chiral aryl diphosphite ligands based on the pyranoside backbones of glucose and galactose were prepared. These ligands were tested in the Cu‐catalyzed asymmetric conjugate addition of diethylzinc to cyclic enones with up to 88% ee. The stereoselectivity was found to be dependent on the ring size of the substrate as well as the ligand and copper source. The enantioselectivity depends on the absolute configuration of the C‐4 stereogenic center of the ligand backbone, while the sense of enantioselectivity is mainly controlled by the configuration of the binaphthyl phosphite moieties.
Second Generation Protocol for Multicomponent Coupling Reactions of Aldehydes, Amides and Dienophiles
Authors: Klaus Stefan , Hübner Sandra , Neumann Helfried , Strübing Dirk , von Wangelin Axel Jacobi , Gördes Dirk , Beller Matthias
Published: August 2004

An improved one‐pot procedure for the three‐component coupling reaction of aldehydes, amides and dienophiles (AAD reaction) has been developed. Compared to known protocols for this type of reaction, the use of aromatic solvents in the presence of dehydrating reagents allows an efficient synthesis of previously not accessible products. Condensation of ubiquitous available aldehydes and amides and subsequent Diels–Alder reactions with dienophiles furnishes endo‐selective amino‐functionalized hexahydroisoindole‐1,3‐dione and tetrahydrophthalic acid derivatives in good yield.
Bony ponticles of the atlas (C1) over the groove for the vertebral artery in humans and primates: Polymorphism and evolutionary trends
Authors: Le Minor Jean‐Marie , Trost Olivier
Published: July 2004

The aim of this study was to ascertain the distribution in primates of the three possible bony ponticles over the groove for the vertebral artery (ventral, lateral, and dorsal ponticles), in order to attempt to understand the variants observed in humans and to ascertain possible evolutionary trends in primates. The material consisted of 393 atlases of extant nonhuman primates representative of 41 genera, and of 500 human atlases (dried bones of adults). For each atlas, we studied the existence and morphology of the ponticles, and the type of association of these three ponticles on a given side, which are theoretically of eight in number (types A–H). The occurrence of these ponticles varied from complete absence to constant presence, according to the genera and taxa of primates. The presence of each of these ponticles in primates can be interpreted as a primitive or plesiomorphic character, and their absence as a derived or apomorphic character. The strepsirhines‐platyrrhines‐cercopithecines group, presenting a predominant primitive pattern (type A), appeared to be separated from the colobines‐hominoids group, presenting predominant derived patterns (type C in colobines, Pongo pygmaeus, and Pan troglodytes, and the more derived type D in Hylobates, Gorilla gorilla, and Homo sapiens). The last derived stage, corresponding to the disappearance of the three atlantal ponticles (type H), was only observed in some individuals in hominoids. A marked intraspecific polymorphism characterized the hominoids. The presence of lateral and dorsal ponticles in humans appeared to correspond to their persistence within the progressive disappearance of the atlantal ponticles, constituting an evolutionary tendency characteristic of primates and particularly of hominoid evolution. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Grasping behavior in tufted capuchin monkeys (Cebus apella): Grip types and manual laterality for picking up a small food item
Authors: Spinozzi Giovanna , Truppa Valentina , Laganà Tiziana
Published: July 2004

This study investigates prehension in 20 tufted capuchins (Cebus apella) in a reaching task requiring individuals to grasp a small food item fixed to a tray. The aim was twofold: 1) to describe capuchins' grasping techniques in detail, focusing on digit movements and on different areas of contact between the grasping fingers; and 2) to assess the relationship between grip types and manual laterality in this species. Capuchins picked up small food items using a wide variety of grips. In particular, 16 precision grip variants and 4 power grip variants were identified. The most frequently used precision grip involved the distal lateral areas of the thumb and the index finger, while the most preferred kind of power grip involved the thumb and the palm, with the thumb being enclosed by the other fingers. Immature capuchins picked up small food items using power grips more often than precision grips, while adult individuals exhibited no significant preference for either grip type. The analysis performed on the time capuchins took to grasp the food and withdraw it from the tray hole revealed that 1) precision grips were as efficient as power grips; 2) for precision grips, the left hand was faster than the right hand; and 3) for power grips, both hands were equally quick. Hand preference analysis, based on the frequency for the use of either hand for grasping actions, revealed no significant hand bias at group level. Likewise, there was no significant relationship between grip type and hand preference. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
The longer you stay, the bigger you get: Length of time and language use in the U.S. are associated with obesity in Puerto Rican women
Authors: Himmelgreen David A. , Pérez‐Escamilla Rafael , Martinez Dinorah , Bretnall Ann , Eells Brian , Peng Yukuei , Bermúdez Angela
Published: July 2004

This cross‐sectional study examined whether length of time in the U.S., language use, and birthplace (proxy measures of acculturation) were associated with body mass index (BMI) and obesity in a sample of 174 low‐income Puerto Rican women from Hartford, Connecticut. The mean BMI for the total sample (N = 174) was 27.39 (S.D. = 5.07), and nearly 34% of the sample was considered obese (BMI ≥ 30). There was a statistically significant increase in BMI with length of time in the U.S. (P = 0.012) and these differences were even greater among women born in Puerto Rico (P = 0.003). Moreover, obesity prevalence was highest among women who had been in the U.S. for 10 years or more (40%), as compared to those who had been in the U.S. less than 1 year (29%; P = 0.045). There were no statistically significant associations between language and BMI for the total sample. However, among bilingual speakers born in Puerto Rico, there were significant differences in BMI according to their level of English fluency. Those who spoke fluent or very good English had a significantly higher BMI (mean = 29.72; SD = 4.12) than women whose English was good to not‐so‐good (mean = 26.8; SD = 5.24; P = 0.016). The findings from this study point to the need for more research on the acculturation process and obesity, in order to design culturally tailored obesity prevention programs. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Chorein detection for the diagnosis of chorea‐acanthocytosis
Authors: Dobson‐Stone Carol , Velayos‐Baeza Antonio , Filippone Lea A. , Westbury Sarah , Storch Alexander , Erdmann Torsten , Wroe Stephen J. , Leenders Klaus L. , Lang Anthony E. , Dotti Maria Teresa , Federico Antonio , Mohiddin Saidi A. , Fananapazir Lameh , Daniels Geoff , Danek Adrian , Monaco Anthony P.
Published: July 2004

Chorea‐acanthocytosis (ChAc) is a severe, neurodegenerative disorder that shares clinical features with Huntington's disease and McLeod syndrome. It is caused by mutations in VPS13A, which encodes a large protein called chorein. Using antichorein antisera, we found expression of chorein in all human cells analyzed. However, chorein expression was absent or noticeably reduced in ChAc patient cells, but not McLeod syndrome and Huntington's disease cells. This suggests that loss of chorein expression is a diagnostic feature of ChAc. Ann Neurol 2004;56:299–302
Antimicrobial finishing of acrilan fabrics with cetylpyridinium chloride
Authors: Cai Zaisheng , Sun Gang
Published: July 2004

Durable antimicrobial properties could be achieved on acrilan fabrics by chemically incorporating biocidal quaternary ammonium salts such as cetylpyridinium chloride (CPC) into the fibers. The chemical interactions between CPC and acrilan fibers were investigated through adsorption isotherm and exhaustion rates of CPC on the fabrics under various conditions. The equilibrium adsorption of CPC on the acrilan fabrics was in good agreement with the Langmuir adsorption isotherm. The study found that CPC concentration, pH value, and finishing temperature and time affected the adsorption process and antimicrobial properties of the acrilan fabrics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 243–247, 2004
Biodegradability of cellulose fabrics
Authors: Park Chung Hee , Kang Yun Kyung , Im Seung Soon
Published: July 2004

Biodegradability of cellulose fabrics was evaluated by use of a soil burial test, an activated sewage sludge test, and an enzyme hydrolysis. Surface changes after biodegradation were observed by optical microscopy. From X‐ray diffraction analysis (XRD), changes in the crystallinities and the internal structures as a result of degradation were also investigated. It was shown that biodegradability decreased in the following order: rayon > cotton ≫ acetate. Rayon fibers, which have a low crystallinity and a low degree of orientation, showed the highest biodegradability in most cases. However, in spite of its low crystallinity, acetate fibers exhibited very low biodegradability, probably because of the presence of hydrophobic groups in its structure. On the other hand, linen showed an inconsistent behavior in that it had the highest biodegradability in the soil burial test, but a lower biodegradability than that of cotton in the activated sewage sludge test. XRD analysis revealed that there was a slight increase in the crystallinity of linen, cotton, and rayon fabrics at the initial stage, but a continuous decrease thereafter. From the correlation analysis, it was revealed that the biodegradability of cellulose fabrics was closely related to the moisture regain of the fibers, which reflects the hydrophilicity and internal structure of the fibers at the same time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 248–253, 2004
Längskraftbeanspruchung von durchgehend geschweißten Schienen auf Brücken für Lastkombinationen
Authors: Ruge Peter , Trinks Carolin , Muncke Martin , Schmälzlin Gerd
Published: July 2004

Die Längskraftbeanspruchung von durchgehend geschweißten Schienen auf Brücken für Lastkombinationen wird im DIN ‐Fachbericht 101, K.3.5, geregelt. Die Lastfälle werden jeweils einzeln für sich nichtlinear analysiert und anschließend durch Summation der Teil ergebnisse zur Gesamtlösung zusammengefaßt. Diese Näherung wird hier durch eine korrekte Kombination zunächst der Lastfälle Temperaturdehnung plus Bremsen ersetzt. Dabei erweist sich der Wechsel des Längsverschiebewiderstandes von unbelastetem zu belastetem Gleis infolge Zugüberfahrt als zusätzlicher Lastfall.
Nachweis des Aufbruchs der Baugrubensohle nach der neuen DIN 1054: 2003‐01
Authors: Hettler Achim , Stoll Christian
Published: July 2004

Nach der Einführung der neuen DIN 1054 im Januar 2003 ist eine Anpassung des Nachweises der Sicherheit gegen Aufbruch der Baugrubensohle an das Teil sicherheitskonzept notwendig geworden. Dabei wird auf das ursprüngliche Verfahren von Weißenbach zurückgegriffen, das sich in der Praxis bewährt hat, dem aber noch das Globalsicherheitskonzept zugrunde liegt. Die neue Vorgehensweise ist im Arbeitskreis Baugruben entwickelt worden und wird anhand von Beispielen erläutert.
Planarien: neue Tiere aus Stammzellen: Regeneration extrem
Authors: Peter Roland
Published: July 2004

Planarien, eine Gruppe frei lebender Plattwürmer
(Strudelwürmer oder Turbellarien), zeichnen sich durch ein extremes
Regenerationsvermögen aus und können aus winzigen
Körperfragmenten vollständige Tiere bilden. Diese Fähigkeit
hängt eng zusammen mit ungeschlechtlicher Fortpflanzung durch Querteilung
und beruht auf einer Gruppe teilungsfähiger Zellen
(“Neoblasten”), die sämtliche Gewebe hervorbringen können. Sie dienen auch der physiologischen Zellerneuerung und der Produktion von Keimzellen. Im Unterschied zu Säugetieren besitzen Plattwürmer keine von den Körperzellen getrennte Keimbahn. Höchstwahrscheinlich gehen alle Neoblasten aus Stammzellen hervor und sind selbst zum Teil Stammzellen. Diese Strategie der Zellerneuerung gibt es auch bei anderen Turbellarienordnungen und mit hoher Wahrscheinlichkeit bei allen Plattwürmern (Plathelminthes). Neue Untersuchungen haben Wege eröffnet, um unter den lichtmikroskopisch einander sehr ähnlichen Neoblasten verschiedene Typen zu unterscheiden. So sollten sich schließlich die eigentlichen Stammzellen identifizieren lassen. Diese dürften bemerkenswerte Ähnlichkeiten zu den somatischen Stammzellen von Säugetieren und Menschen aufweisen.
Matthias Jacob Schleiden
Authors: Irsch Wilhelm
Published: July 2004

Matthias Jacob Schleiden (1804‐1881), der 23 Jahre an der Friedrich‐ Schiller‐Universität in Jena wirkte, gilt als Vater der Zellbiologie. Weniger bekannt ist, dass der rührige Botaniker die erste fruchtbare Zusammenarbeit zwischen der Universität und der örtlichen Industrie anregte. Dass er konsequent die darwinistische Neuinterpretation der Anthropologie verfocht und die wissenschaftliche Diskussion im 19. Jahrhundert entscheidend prägte, ist ebenfalls wenig bekannt und erforscht. Wissenschaftshistoriker der Universität Jena haben den 200. Geburtstag Schleidens zum Anlass genommen, um erstmalig in einer Gesamtausgabe seine anthropologischen Schriften zu publizieren.
Welche Gene machen den Menschen zum Menschen?
Authors: Kronberg Inge
Published: July 2004

Die im Mai 2004 veröffentliche Sequenz von Chromosom 22 des Schimpansen erreicht erstmals eine Genauigkeit, die der Sequenzierung des menschlichen Genoms entspricht. Das „International Chimpanzee Chromosome 22 Consortium” hat sich zur Aufgabe gestellt, die Gene herauszufinden, die für die typischen Unterschiede zwischen Schimpanse und Mensch verantwortlich sind.
Chronic pain after open mesh and sutured repair of indirect inguinal hernia in young males
Authors:   Swedish Hernia Data Base the Danish Hernia Data Base, Bay-Nielsen M , Nilsson E , Nordin P , Kehlet H
Published: August 2004

Background

Chronic pain is common after herniorrhaphy, but the effect of surgical technique (mesh versus non-mesh repair) and the social consequences of the pain have not been established. The aim of this study was to analyse chronic postherniorrhaphy pain and its social consequences in young males operated on for an indirect inguinal hernia with a Lichtenstein mesh repair, Shouldice or Marcy (annulorrhaphy) repair.

Methods

This was a postal questionnaire study carried out within the Danish and Swedish Hernia Database Collaboration. Some 2612 patients responded (response rate 80·9 per cent), of whom 1250 had undergone a Lichtenstein, 630 a Shouldice and 732 a Marcy repair.

Results

Chronic pain had been experienced within the previous month by 22·9 per cent of the patients who responded. There was an overall decrease in pain with time, from 29·7 per cent at 6–12 months to 18·1 per cent at 37–48 months after surgery, with no overall differences between the three types of repair. Pain was more common in patients younger than 40 years of age. Some 3·9 per cent of patients described the pain as moderate to severe and as frequent or constant. Of all patients with pain, 10·7 per cent experienced it as worse after than before surgery, and 56·6 per cent stated that it interfered with social activities.

Conclusion

Chronic pain is common after primary inguinal hernia repair in young males, but there is no difference in the pain associated with open mesh and non-mesh repair.
Monosaccharides as Silicon Chelators: Pentacoordinate Bis(diolato)(phenyl)silicates with the cis‐Furanose Isomers of Common Pentoses and Hexoses
Authors: Klüfers Peter , Kopp Florian , Vogt Martin
Published: July 2004

Five‐coordinate phenylsilicates are formed from the reaction of trimethoxy(phenyl)silane with monosaccharides in methanol in the presence of a stoichiometric amount of base. Five complexes have been isolated and characterized with two ketoses and three aldopentoses. The silicon central atom in [K([18]crown‐6)][PhSi(β‐D‐Fruf 2,3H−2)2]⋅MeOH (1, Fru=fructose) is part of two chelate rings, with the ligands being β‐D‐fructofuranose‐O 2,O 3 dianions. The β‐furanose isomer is best suited for silicon ligation because it exhibits a torsion angle close to 0° for the most acidic diol function, thus assuring a flat chelate ring. The same structural principles are also found in [K([18]crown‐6)][PhSi(β‐D‐Araf1,2H−2)2]⋅2 MeOH (2, Ara=arabinose), [K([18]crown‐6)][PhSi(α‐D‐Ribf1,2H−2)2] (3, Rib=ribose), [K([18]crown‐6)][PhSi(α‐D‐Xylf1,2H−2)2]⋅ acetone (4, Xyl=xylose), and [K([18]crown‐6)][PhSi(α‐D‐Rulf2,3H−2)2] (5, Rul=ribulose).
Supramolecular Motifs in s‐Block Metal‐Bound Sulfonated Monoazo Dyes, Part 1: Structural Class Controlled by Cation Type and Modulated by Sulfonate Aryl Ring Position
Authors: Kennedy Alan R. , Kirkhouse Jennifer B. A. , McCarney Karen M. , Puissegur Olivier , Smith W. Ewen , Staunton Edward , Teat Simon J. , Cherryman Julian C. , James Rachel
Published: July 2004

The solid‐state structures of 43 Li, Na, K, Rb, Mg, Ca and Ba salts of para‐ and meta‐sulfonated azo dyes have been examined and can be categorised into three structural classes. All form alternating organic and inorganic layers, however, the nature of the coordination network that forms these layers differs from class to class. The class of structure formed was found to be primarily governed by metal type, but can also be influenced by the nature and position of the organic substituents. Thus, for the para‐sulfonated azo dyes, Mg compounds form solvent‐separated ion‐pair solids; Ca, Ba and Li compounds form simple coordination networks based on metal–sulfonate bonding; and Na, K and Rb compounds form more complex, higher dimensional coordination networks. Compounds of meta‐sulfonated azo dyes follow a similar pattern, but here, Ca species may also form solvent‐separated ion‐pair solids. Significantly, this first attempt to classify such dyestuffs using the principles of supramolecular chemistry succeeds not only for the simple dyes used here as model compounds, but also for more complex molecules, similar to modern colourants.
Ermittlung des Einflusses von Fettrohstoff und Prozesstechnologie auf die Oxidationsstabilität von Fettsäuremethylester
Authors: Dittmar T. , Ondruschka B. , Haupt J. , Lauterbach M.
Published: July 2004

No abstracts.
Aufreißende Filmströmung auf geneigten Oberflächen
Authors: Hoffmann A. , Ausner I. , Repke J.‐U. , Wozny G.
Published: July 2004

No abstracts.
Verbesserung der Oxidationsstabilität von Fettsäuremethylester mit Antioxidantien – Grenzen des Rancimat‐Tests
Authors: Dittmar T. , Ondruschka B. , Haupt J. , Lauterbach M.
Published: July 2004

No abstracts.
NOP – Ein neues organischchemisches Grundpraktikum: Nachhaltigkeit per Internet
Authors: Ranke Johannes , König Burkhard , Diehlmann Achim , Kreisel Günter , Nüchter Matthias , Störmann Reinhold , Hopf Henning
Published: July 2004

Das Neue und nachhaltigere Organisch‐chemische Praktikum
NOP nutzt die zusätzlichen Möglichkeiten, die eine Website im Vergleich zu einem konventionellen Laborpraktikum in Buchform hat, um angehenden Synthesechemikern ein breiteres Verständnis der durchgeführten Versuche zu vermitteln. Hierzu gehören Informationen zu analytischen Methoden, Hintergrundinformationen zu den eingesetzten und entstehenden Stoffen sowie Kennzahlen zur Bewertung von Stoff‐ und Energieeffizienz der Versuche. Nicht zuletzt wird dabei Hintergrundwissen zum Konzept der nachhaltigen Entwicklung für den Themenbereich Synthesechemie aufbereitet.
Ultraschnelle Elektronenkristallographie
Authors: Harrer Roswitha
Published: July 2004

Mit der ultraschnellen Elektronenkristallographie lassen sich neue Wege einer wahrlich “zeitaufgelösten” Chemie beschreiben. Atombewegungen von Hundertstel Ångström, Zeitfenster von Billionstel Sekunden ‐ die Grenzen, chemische Vorgänge zu beobachten, scheinen in eine andere Dimension gerückt.
Die Chemie der Lakritzschnecke — Teil 2
Authors: Roth Klaus
Published: July 2004

Im letzten Heft verfolgten wir den Weg vom Süßholz (Glycyrrhiza glabra) bis zur Lakritzschnecke. Obwohl seit Jahrhunderten in der Volksmedizin bei Magenbeschwerden und Erkrankungen der oberen Luftwege bewährt, konnte der Wirkstoff der Lakritze, die Glycyrrhetinsäure [1], erst 1936 in reiner Form isoliert und charakterisiert werden. Die sich anschließende Strukturaufklärung war fast ein Alleingang von Leopold Ruzžička und seiner Arbeitsgruppe. Begleiten wir ihn auf seinem mühsamen Weg von der Summenformel C30H46O4 bis zur Strukturformel. Vergleichen wir dann, wie Chemiker heute die Struktur eines so komplexen Naturstoffs mit Hilfe spektroskopischer Methoden bestimmen.
Keramik und Metalle durch Spritzguss in Form gebracht
Authors: Borchard‐Tuch Claudia
Published: July 2004

Geometrisch komplexe Bauteile aus Werkstoffen wie Keramik, Hartmetallen und Superlegierungen lassen sich durch Pulverspritzgießen herstellen – eine moderne Technologie, die aus dem klassischen Spritzguss für die Kunststoffverarbeitung entlehnt ist.
Radioaktive Spürhunde
Authors: Hübner Carl
Published: July 2004

Radioaktive Isotope könnten neue Impulse in der Krebstherapie setzen. Gekoppelt an zielsichere Eiweiße finden sie ihren Weg direkt zu den Tumorzellen – und zerstören diese mit ihrer Strahlung. In diesem Jahr bekam das erste derartige Radioimmuntherapeutikum eine EU‐Zulassung.
Adult de novo acute myeloid leukemia with t(6;11)(q27;q23)
Authors: Blum William , Mrózek Krzysztof , Ruppert Amy S. , Carroll Andrew J. , Rao Kathleen W. , Pettenati Mark J. , Anastasi John , Larson Richard A. , Bloomfield Clara D.
Published: July 2004

BACKGROUND

Acute myeloid leukemia (AML) with t(6;11)(q27;q23) is a well established but rare entity, and few studies have reported the full clinical, hematologic, and outcome data of patients with this disease.

METHODS

To characterize the features of t(6;11) AML, the authors searched the Cancer and Leukemia Group B (CALGB) cytogenetic database comprising 2667 adults with newly diagnosed, de novo AML and identified 16 patients (0.6%) with t(6;11). A review of the literature identified 33 adults with de novo t(6;11) AML for whom survival data were available.

RESULTS

CALGB patients had a median age of 45 years (range, 22–65 years) and commonly presented with French–American–British (FAB) subtype M4 or M5 (81%). Gingival involvement at presentation was common (31%). All patients with gingival involvement had FAB M4. Compared with other patients with M4 AML in the CALGB database (n = 429), patients with M4 and t(6;11) (n = 7) had a higher frequency of gingival hypertrophy at presentation (71% vs. 17%, P = 0.003). Patients with t(6;11) were more likely to be African American (P = 0.02) and to die during induction (P = 0.03) than those without t(6;11). The complete response (CR) rate was 69% (11 of 16 patients), and CR duration was short (median, 9 months). The estimated probability of 2‐year survival was 13%. Both long‐term survivors received allogeneic stem cell transplantation. The estimated probability of 2‐year survival of patients reported in the literature was 15%.

CONCLUSIONS

Although the patient sample was small, the authors suggested that investigational approaches, including allogeneic transplantation, be considered for adults with t(6;11) AML. Cancer 2004. © 2004 American Cancer Society.
Cytokeratin‐positive cells in sentinel lymph nodes in breast cancer are not random events
Authors: King Tari A. , Ganaraj Archana , Fey Jane V. , Tan Lee K. , Hudis Clifford , Norton Larry , Cody Hiram S. , Borgen Patrick I.
Published: July 2004

BACKGROUND

The incidence of immunohistochemistry (IHC)‐detected epithelial cell displacement in sentinel lymph node (SLN) biopsy is unknown. In the current study, we address this question by examining the pattern of SLN involvement in patients undergoing prophylactic mastectomy (PM) at Memorial Sloan‐Kettering Cancer Center (New York, NY).

METHODS

Between January 1999 and January 2003, 5275 patients underwent SLN biopsy. Unilateral or bilateral PM with SLN biopsy was performed in 143 (2.7%) patients, representing 163 PM cases.

RESULTS

Occult carcinoma was identified in 13 of 163 (8.0%) PM specimens. Two patients with occult invasive carcinoma had positive SLNs (hematoxylin and eosin). In the remaining 150 PM cases without occult carcinoma (130 patients), 89% underwent IHC analysis of the SLNs. Of these 130 patients, 43 (33%) had one or more prior biopsies in their “cancer‐free” breast, a median of 43 days (range, 3–314 days) before PM. A total of 310 SLNs were examined by IHC (mean, 2.3 lymph nodes per PM case). Only 1 of 130 (0.8%) patients without occult carcinoma had an IHC‐positive SLN. This patient had Stage IIIC carcinoma of the contralateral breast. IHC‐positive SLNs were not identified in any of the 43 patients with a history of prior biopsy. Therefore, only 1 IHC‐positive SLN was detected in 310 (0.3%) lymph nodes examined.

CONCLUSIONS

IHC‐positive cells in SLNs are rare in the absence of cancer and are not the result of previous breast instrumentation. Although the prognostic significance of IHC‐positive cells remains controversial, the current study suggests that they are not random events. Cancer 2004. © 2004 American Cancer Society.
Congestion control for multimedia applications in the wireless internet
Authors: Rakocevic Veselin
Published: July 2004

This paper provides a parallel review of two important issues for the next‐generation multimedia networking. Firstly, the emerging multimedia applications require a fresh approach to congestion control in the Internet. Currently, congestion control is performed by TCP; it is optimised for data traffic flows, which are inherently elastic. Audio and video traffic do not find the sudden rate fluctuations imposed by the TCP multiplicative‐decrease control algorithm optimal. The second important issue is the mobility support for multimedia applications. Wireless networks are characterized by a substantial packet loss due to the imperfection of the radio medium. This increased packet loss disturbs the foundation of TCP's loss‐based congestion control. This paper contributes to the ongoing discussion about the Internet congestion control by providing a parallel analysis of these two issues. The paper describes the main challenges, design guidelines, and existing proposals for the Internet congestion control, optimised for the multimedia traffic in the wireless network environment. Copyright © 2004 John Wiley & Sons, Ltd.
Epstein‐Barr virus nuclear antigen 1 evades direct immune recognition by CD4+ T helper cells
Authors: Mautner Josef , Pich Dagmar , Nimmerjahn Falk , Milosevic Slavoljub , Adhikary Dinesh , Christoph Heike , Witter Klaus , Bornkamm Georg W. , Hammerschmidt Wolfgang , Behrends Uta
Published: July 2004

The Epstein‐Barr virus (EBV) nuclear antigen 1 (EBNA1) is the only viral protein regularly expressed in EBV‐associated malignancies. Immune recognition of EBNA1 by CD8+ T cells is prevented by an internal glycine‐alanine repeat (GAr) which blocks proteasomal degradation. To test whether EBV‐infected cells could be recognized by T helper cells, human CD4+ T cell clones specific for EBNA1 were isolated from latently EBV‐infected individuals. These T cells, however, failed to recognize EBV‐positive target cells. To investigate whether endogenous presentation of EBNA1 epitopes on MHC class II was prevented by the GAr domain, a mutant EBV strain with an EBNA1 lacking the GAr (EBNA1ΔGA) was generated and used to establish an Epstein‐Barr virus‐immortalized lymphoblastoid B cell line (LCL). The EBNA1ΔGA LCL were not recognized by the EBNA1‐specific T cell clones either, indicating that the GAr domain does not mediate this effect. Immune recognition could be restored by overexpression of EBNA1, for which at least 60‐fold higher levels of both EBNA1 or EBNA1ΔGAr protein were required. These results demonstrate that EBNA1 evades direct recognition by CD4+ T helper cells, since its steady state level is below the threshold required for efficient presentation on MHC class II. These findings have important implications for the design of immunotherapeutic approaches to target EBV‐positive malignancies.
Complement inhibitor membrane cofactor protein (MCP; CD46) is constitutively shed from cancer cell membranes in vesicles and converted by a metalloproteinase to a functionally active soluble form
Authors: Hakulinen Juha , Junnikkala Sami , Sorsa Timo , Meri Seppo
Published: July 2004

Human cell‐surface protein CD46 protects cells from complement damage, regulates immune functions through signaling and acts as a receptor for certain pathogenic microbes. Multiple molecular weight isoforms of membrane bound CD46 are produced by alternative splicing of the CD46 mRNA in an area coding for the serine/threonine/proline‐rich region or for the cytoplasmic tail. We demonstrate that CD46 becomes proteolytically modified on cell membranes. We observed that tumor cells liberated intact 60–65 kDa forms of CD46 into the cell culture medium on the surface of vesicles with a diameter of 200 nm. Furthermore, soluble CD46 (55–60 kDa) containing the glycosylated STP‐region but lacking the hydrophobic transmembrane sequence and cytoplasmic domains was released from tumor cell membranes. The use of selective inhibitors indicated that CD46 release is due to specific cleavage by a metalloproteinase. Exposure of the cells to hydrogen peroxide (H2O2) or their detachment from the pericellular matrix increased the shedding of soluble CD46. Both vesicular and soluble forms of CD46 remained functional and promoted C3b cleavage by factor I. The results show that the functional activity of CD46 is not restricted to the tumor cell membranes but can be liberated in vesicles and by a metalloproteinase.
Fratricide of CD8+ cytotoxic T lymphocytes is dependent on cellular activation and perforin‐mediated killing
Authors: Su Michael Wei‐Chih , Pyarajan Saiju , Chang Jin‐Hong , Yu Chao‐Lan , Jin Yong‐Jiu , Stierhof York‐Dieter , Walden Peter , Burakoff Steven J.
Published: July 2004

CD8+ CTL mediate the destruction of cells displaying foreign peptides in association with class I MHC molecules. Since CD8+ CTL themselves express class I MHC molecules, a phenomenon known as “fratricide” can be elicited by T cells presenting antigens to other CTL. To gain insight into this mechanism, fratricide was induced in a clone of class I‐restricted CD8+ CTL by incubating the T cells with their agonist ligand, an octamer peptide derived from chicken ovalbumin. Our results indicate that agonist peptide not only stimulates proliferation and cytolysis of CTL but also initiates signaling pathways that are pertinent to T cell activation, including the mobilization of transcription factors. Also consistent with T cell activation, fratricide induced the transcription and translation of the pro‐inflammatory cytokines TNF‐α and IFN‐γ. Finally, the essential role of perforin, as opposed to Fas/FasL, in fratricide was demonstrated by the selective inhibition of cytolysis with an inhibitor of the perforin pathway, the absence of FasL expression on T cells and the presence of lytic granules visible by electron microscopy. Collectively, these findings reveal that fratricide is mediated by T cell activation and perforin‐mediated cytolysis. These results may have implications for the regulation of CD8+ CTL in immune responses.
Inhibition of cell surface MHC class II expression by Salmonella
Authors: Mitchell Erin K. , Mastroeni Pietro , Kelly Adrian P. , Trowsdale John
Published: July 2004

Peptide presentation by MHC molecules is an essential component of the adaptive immune response. To persist in a host, many pathogens have evolved strategies that interfere with MHC antigen‐presentation. We show that in human cells harboring intracellular Salmonella, MHC class II cell surface expression was substantially reduced. The effect was specific for MHC class II as expression of additional surface receptors remained unchanged. We investigated the underlying mechanism and showed that class II biosynthesis and peptide loading were unaffected by the presence of Salmonella; however, infection led to an intracellular accumulation of mature molecules. The intracellular class II colocalized with lysosome‐associated membrane protein‐1 and HLA‐DM but not with the Salmonella‐containing vacuole. Using Salmonella mutants defective in different components and effectors of the Salmonella pathogenicity island‐2 type‐III secretion system, we traced the effect on class II to the sifA locus. SifA has been shown to be involved in recruiting membrane for the Salmonella‐containing vacuoles. Our data suggest an additional role for SifA in interfering with MHC class II antigen‐presentation.
Characterisation of Fuel Cell Membranes as a Function of Drying by Means of Contact Angle Measurements
Authors: Brack H.‐P. , Slaski M. , Gubler L. , Scherer G.G. , Alkan S. , Wokaun A.
Published: July 2004

In another paper in this volume, it is demonstrated that the electrochemical interface in MEAs, and thus the polarization performance of the resulting fuel cells, can be improved by optimising the hot‐pressing procedure in the MEA preparation. In particular, the extent of drying of the membrane during MEA preparation was shown to be critical. In the present investigation, the effect of the drying process, and thus water content, on the hydrophilicity, wetting, and surface energies of some fuel cell membranes is examined. Wetting and surface energies are well known to influence the bonding behaviour of materials. Conclusions about how membrane drying and changes in water content influence membrane bonding and the relative importance of these surface effects are drawn.
Performance and Durability of Membrane Electrode Assemblies Based on Radiation‐Grafted FEP‐g‐Polystyrene Membranes
Authors: Gubler L. , Kuhn H. , Schmidt T.J. , Scherer G.G. , Brack H.‐P. , Simbeck K.
Published: July 2004

Membrane electrode assemblies (MEAs) based on radiation‐grafted proton exchange membranes developed at PSI have shown encouraging performance in the past in hydrogen and methanol fuelled polymer electrolyte fuel cells. In this study, the effect of the pre‐treatment of crosslinked radiation‐grafted FEP membranes prior to lamination with the electrodes on the performance of the MEAs was investigated. Two approaches were assessed separately and in combination: (1) the impregnation of the radiation‐grafted membranes with solubilised Nafion®, and (2) the use of a swollen vs. dry membrane. It is found that the combination of coating the membrane with Nafion® ionomer and hot‐pressing the MEA with the membrane in the wet state produce the best single cell performance. In the second part of the study, the durability of an MEA, based on a radiation‐grafted FEP membrane, was investigated. The performance was stable for 4,000 h at a cell temperature of 80 °C. Then, a notable degradation of the membrane, as well as the electrode material, started to occur as a consequence of either controlled or uncontrolled start‐stop cycles of the cell. It is assumed that particular conditions, to which the cell is subjected during such an event, strongly accelerate materials degradation, which leads to the premature failure of the MEA.
Bilayer Anodes for Improved Reformate Tolerance of PEM Fuel Cells
Authors: Janssen G.J.M. , de Heer M.P. , Papageorgopoulos D.C.
Published: July 2004

The concept of bilayer anodes for improved reformate tolerance was analysed using model calculations. It was found that for a bilayer anode to give good results the catalyst in the layer adjacent to the backing should enable CO oxidation at low potentials and have a relatively low rate of H2 oxidation. The catalyst in the second layer should enable fast H2 oxidation, and have limited CO adsorption. Experimental results are presented showing that the bilayer anode works especially well with reformate gas. It was found that the water gas shift equilibrium plays an important role in the mechanism for reformate tolerance. The implementation of the bilayer concept seems to be very useful in optimising both CO and CO2 tolerance of PEMFCs, including at high fuel utilisation.
Fuel Cells for People
Authors: Cropper M.
Published: July 2004

Portable power promises to be the first truly commercial market for fuel cell technology. In this keynote presentation, which is accompanied by an up‐to‐date survey published on 1 July 2003 at www.fuelcelltoday.com/surveys, we review the activity that has so far taken place worldwide in this exciting sector of the fuel cell industry. Features include a review of the number of systems so far built, the different fuel cell types under development, fuel choice and region of development. In addition, this article will also discuss the various potential markets for portable fuel cells, and the some of the issues that are associated with them.
Characterising PEM Fuel Cell Performance Using a Current Distribution Measurement in Comparison with a CFD Model
Authors: Hakenjos A. , Tüber K. , Schumacher J.O. , Hebling C.
Published: July 2004

The characterisation of a proton exchange membrane (PEM) fuel cell with a straight channel flow field design is performed. Spatially resolved current distribution measurements, at different air flow rates, are compared to numerical simulation results. The numerical model is validated by agreement of the measured and simulated current distribution.

The test cell is segmented. It is operated at steady state conditions and the gas flow rates and cell temperature are controlled. The numerical simulation is realised with a PEM fuel cell model based on FLUENT™ computational fluid dynamics (CFD) software. It accounts for mass transport in the gaseous phase, heat transfer, electrical potential field and the electrochemical reaction. It provides three‐dimensional distributions of, e.g., current densities, reactant concentrations and temperature.
The impact of time duration between trades on the price of treasury note futures contracts
Authors: Holder Mark E. , Qi Min , Sinha Amit K.
Published: July 2004

Recent research in finance has indicated that the institutional structure in which financial asset prices are determined can have a nontrivial impact on pricing. This report examines transaction level data for Treasury Note futures contracts traded at the Chicago Board of Trade (CBOT) to identify institutional, or market microstructure, impacts on the pricing of these contracts. Relatively few articles have conducted empirical research on the microstructure of U.S. futures trading due to the limited availability of comprehensive transaction level data from the futures exchanges. This report uses the CBOT's Computerized Trade Reconstruction database, a comprehensive transaction level dataset, to identify the price impact of the time duration between trades in a manner analogous to that of A. Dufour and R. F. Engle (2000). Unique differences from prior research include the application to futures contracts with their relative higher frequency of trading, as well as the investigation of the price impact of the number of active traders present on the trading floor and the trading volume. Subsequent price and sign of trade significantly relate to the time duration between trades, the number of floor brokers, and the trading volume. © 2004 Wiley Periodicals, Inc. Jrl. Fut Mark 24:965–980, 2004
Sonographically guided injection of anesthetic for iliopsoas tendinopathy after total hip arthroplasty
Authors: Wank Ross , Miller Theodore T. , Shapiro Jeffrey F.
Published: July 2004

We report 2 patients who developed pain in the region of the iliopsoas tendon after undergoing total hip arthroplasty. The pain was temporarily relieved by sonographically guided injection of steroid and anesthetic and was subsequently treated by surgical release of the tendon. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:354–357, 2004
Value of sonography in the diagnosis of abnormal vaginal bleeding
Authors: Dubinsky Theodore J.
Published: July 2004

Abnormal vaginal bleeding is one of the most common presenting complaints in women of any age seeking gynecologic health care. Two of the most frequently used diagnostic tests to investigate the cause of the bleeding are endometrial biopsy and transvaginal sonography. The most worrisome cause of abnormal bleeding is endometrial carcinoma, yet benign etiologies are far more prevalent, including fibroids, polyps, and endometrial atrophy. Endometrial biopsy and transvaginal sonography have equal sensitivities for carcinoma, but sonography is far more effective in diagnosing benign disease. This article reviews the state‐of‐the‐art in the diagnostic evaluation of abnormal vaginal bleeding and analyzes the data, with emphasis on the prevalence of benign and malignant disease as the basis for determining whether sonography or biopsy is more cost‐effective in evaluating women with abnormal vaginal bleeding. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:348–353, 2004