bluuebunny/crossref_metadata_2025 huggingface dataset:
Malignant degeneration of presacral teratoma in the Currarino anomaly
Authors: Urioste Miguel , del Carmen Garcia‐Andrade M. , Valle Laura , Robledo Mercedes , González‐Palacios Fernando , Méndez Ramiro , Ferreirós Joaquin , Nuño Javier , Benítez Javier
Published: May 2004

The autosomal dominant Currarino anomaly (CA) comprises a presacral mass, partial sacral agenesis, and anorectal defects. Chronic constipation in childhood related to anorectal defects is the most common presenting symptom and hemisacrum the most frequent malformation. The presacral mass may be an anterior meningomyelocele, teratoma, hamartoma, dermoid cyst, neuroenteric cyst, or a combination of these. Sepsis and meningitis are frequent serious problems related to the anterior meningomyelocele, whilst malignant transformation of presacral teratoma is a rare, severe complication in CA. Here, we report on a three‐generation family segregating the CA, presenting with anorectal defects, severe constipation, and sacral involvement in affected relatives. Teratoma was the most frequent component of the presacral mass. In this kindred a 22‐year‐old man died of a neuroendocrine tumor, probably related to malignant change in a presacral teratoma. A novel mutation in HLXB9 consisting of a 24‐bp deletion and insertion of 2‐bp into exon 1, was identified in all patients and in also three asymptomatic members of this family. Anterior meningomyelocele is the most frequently reported component of the presacral masses in CA; however, presacral teratomas carry an inherent risk for malignancy that must be considered in the counseling, surgical treatment options, and follow‐up of CA patients. © 2004 Wiley‐Liss, Inc.
Teil 1: Entwicklungsstand und Flankenpegeldifferenz
Authors: Sälzer Elmar , Freimuth Herbert
Published: May 2004

Nach mehr als 20 Jahren wird zusammenfassend über den gegenwärtigen Stand der Erkenntnisse zum Schallschutz von Hohlraumböden berichtet, aufbauend auf über 500 Messungen im akustischen Laboratorium und mehreren hundert Messungen am Bau, letztere immer im Zusammenklang von Wänden, Decken, Hohlraumböden und sonstigen Bauteilen.
Untersuchung der thermisch‐hygrischen Eigenschaften von Ziegeln mit Hohlraumfüllung aus Recyclingmaterial
Authors: Korjenic Azra , Zach Jiri , Dreyer Jürgen , Stastnik Stanislav
Published: May 2004

In dem Forschungsprojekt wurde untersucht, ob Ziegel mit einfacher Hohlraumstruktur durch Verwendung einer wärmedämmenden Hohlraumfüllung einen höheren Wärmedurchlaßwiderstand haben. Als Dämmstoff wurde ein Recyclingdämmaterial aus Reststoffen aus der Produktion von Polystyrolplatten sowie Holzbauteilen, die mittels Zementleim zu einem Gemisch verarbeitet wurden, verwendet. Es wurde der Einfluß von Anordnung und Stärke der Dämmschicht sowie von Lage und Geometrie der Hohlräume des Ziegelbausteines auf die thermisch‐hygrischen Zustände untersucht. Für die Untersuchung der thermischen Eigenschaften und der Ermittlung der Wärmedurchgangskoeffizienten wurde das Programm THERM verwendet, das den Wärmetransport durch Wärmeleitung im Ziegelscherben und die Transportmechanismen Wärmeleitung, Konvektion und Strahlung in den luftgefüllten Hohlräumen berücksichtigt. Zur Untersuchung des Feuchtigkeitstransports in den Ziegelsteinen wurde das Programmpaket WUFI 2D verwendet. Die Untersuchungen haben gezeigt, daß die so strukturierten Ziegel‐Verbundsteine einen etwa doppelt so hohen Dämmwert haben, wie der ursprüngliche Ziegelstein. Die hygrischen Zustände können im Ziegel teilweise über 80 % Luftfeuchtigkeit betragen. Diese Belastung wird als unkritisch eingeschätzt, weil die Holzpartikel mit Zementschlämme umhüllt sind.
Abschätzung des Windeinflusses auf die Funktion dezentraler Fassadenlüftungsgeräte
Authors: Hartwig Helge , Hellwig Runa Tabea , Hausladen Gerhard
Published: May 2004

Dezentrale Lüftungsgeräte können über einen Außenanschluß Luft fördern und dabei Teilklimafunktionen (Heizen, Kühlen) für die versorgten Räume erfüllen. Der geförderte Volumenstrom ist neben der Konstruktion des Gerätes auch von den Windverhältnissen im Bereich der Außenluftansaugung abhängig. Es wird ein Verfahren vorgeschlagen, mit dem über statistische Wetterdaten etwaige Einschränkungen für den Betrieb abgeschätzt werden können. So kann die Häufigkeit von thermisch induzierteren Luftströmungen (hohe Lufttemperatur im Ansaugbereich) und Abweichungen vom Nenn‐Volumenstrom quantitativ beurteilt werden. Ebenso können Anforderungen an ein Gerät abgeleitet werden. Das Verfahren eignet sich insbesondere auch für die ersten Schritte beim Entwurf von Gebäuden.
Baulicher Brandschutz für großflächige Dächer — Kommentar zur neuen Fassung von DIN 18234
Authors: Brein Dieter , Hegger Thomas
Published: May 2004

Dächer, die die in DIN 18234 Teile 1 bis 4 beschriebenen Anforderungen erfüllen, können das Brandschutzniveau von großflächigen Dächern bei Brandbeanspruchung von unten ohne klassifizierbare Feuerwiderstandsdauer erheblich verbessern. Ein Brand im Innenraum wird das Dach damit entweder nicht mehr oder nur noch so verzögert am Brandgeschehen beteiligen können, daß eine rechtzeitig alarmierte und eintreffende Feuerwehr realistische Chancen erhält, das Brandereignis noch auf eine kleinere Fläche beschränkt vorzufinden und bekämpfen zu können. Die Aufnahme von DIN 18234 als ein Regeldachaufbau in die MusterIndustriebau‐Richtlinie (MIndBauRL) war ein erster wichtiger Schritt der baurechtlichen Anerkennung dieser Norm. Es bleibt zu wünschen, daß die positiven Möglichkeiten nun auch bei den künftig überarbeiteten bauordnungsrechtlichen Vorschriften anderer Sonderbauten berücksichtigt werden können.
Hintergründe zur Nutzlastabminderung nach DIN 1055‐3
Authors: Schmidt Holger , Cornelius Volker
Published: May 2004

Es werden die Möglichkeiten der Nutzlastabminderung nach DIN 1055‐3 vorgestellt und eigene Untersuchungsergebnisse bezüglich der Nutzlastvariabilität in Wohngebäuden präsentiert. Die hieraus resultierenden Erkenntnisse stehen stellvertretend für die Flächen‐ und Stockwerksabhängigkeit von Nutzlasten und können leicht auf andere Gebäudekategorien übertragen werden.
Kontinuumsmechanik in der Stahlbeton‐Praxis
Authors: Hartl Helmut
Published: May 2004

Es wird anhand von drei Beispielen der Ingenieurpraxis die Bedeutung der nichtlinearen Rechenmethoden gezeigt. Zu Beginn soll eine kurze Darstellung der Theorie zeigen, auf welchen Grundlagen das entwickelte Finite Element Programm basiert, welche Materialgesetzte verwendet werden und welche Eingabedaten erforderlich sind. Im ersten Beispiel wird das Verbundverhalten von zwei unterschiedlich alten Betonschichten erörtert. Es wird vor allem auf die Spannungen, welche durch das zeitversetzte Kriechen und Schwinden entstehen, eingegangen. Im zweiten Beispiel behandelt das Tragverhalten von Brückenkragplatten im Anprallastfall, wenn sie mit modernen hochwertigen Rückhaltesystemen nachgerüstet werden, für die sie ursprünglich nicht ausgelegt wurden. Das dritte Beispiel zeigt eine auf einfache Weise bewehrte Rahmenecke, bei welcher das Verbundverhalten der Bewehrung die Traglast bestimmt.
Querkraftwiderstand betonstabbewehrter Bauteile ohne Querkraftbewehrung
Authors: Basche Holger D. , Keller Christina , Novák Balthasar
Published: May 2004

Das Querkrafttragverhalten von Stahlbetonbauteilen ohne Querkraftbewehrung ist bis heute Gegenstand zahlreicher Untersuchungen. Während für die unterschiedlichen Modelle zum Querkraftabtrag z. T. weitführende Materialbeschreibungen bzw. konstitutive Gesetze für Beton verwendet werden, wird in aller Regel ein linear elastisch — ideal plastisches Verhalten der Zugbewehrung vorausgesetzt. Vorgespannte Betonstäbe, über die in vorangegangenen Artikeln [1] bis [3] bereits berichtet wurde, zeigen nach der Dekompression ein ausgeprägt nichtlineares Verhalten, und die Vermutung liegt nahe, daß die Gültigkeit der für Stabstahl geltenden Bemessungsvorschläge hinsichtlich der Querkrafttragfähigkeit überprüft werden muß. Im vorliegenden Artikel wird über Querkraftversuche an mit vorgespannten Betonstäben bewehrten Balken berichtet und Bezug auf das Bemessungsverfahren der aktuellen DIN 1045‐1 genommen.
Spritzbeton für komplexe, innerstädtische Tunnelbauarbeiten
Authors: Schließler Otto , Peter Carsten
Published: May 2004

Derzeit befindet sich in Dortmund im Rahmen der Ost‐West‐Unterquerung der Innenstadt das Stadtbahn‐Baulos S10.1 in Bau. Das Baulos ist gekennzeichnet durch komplexe Tunnelbauarbeiten mit Auffahrung von tangierenden und kreuzenden Tunneln im Innenstadtbereich.

Solche anspruchsvollen Baumaßnahmen bergen Risiken in sich, die in der Ausschreibung in technischer und vertraglicher Hinsicht geregelt sein müssen. Der Beitrag stellt das Baulos mit seinen Besonderheiten und den planerischen, geologischen und örtlichen Randbedingungen vor, auf deren Basis die Ausschreibung aufgestellt wurde. Die Arbeiten für das Baulos begannen im Juni 2002 und sollen Ende 2005 abgeschlossen sein.

Erste Erfahrungen aus der Bauausführung werden vorgestellt.
Zur Ermittlung der Beton‐ und Stahlspannungen
Authors: Duţulescu Eugen
Published: May 2004

Die Begrenzung der Beton‐ und Stahlspannungen wird in DIN 1045‐1 [1] wie auch im EC 2 [2] ausdrücklich verlangt. Es wird ein allgemeines Rechenverfahren zur Ermittlung dieser Spannungen für Stahlbetonquerschnitte, die auf Biegung mit Normalkraft beansprucht sind, vorgestellt. Für die üblichen praktischen Fälle werden Tabellen dargestellt.
Die Optimierte Projektentwicklung
Authors: Peer Walter
Published: May 2004

Anhand eines kürzlich vorgebrachten Vorschlages eines Bauprojekts für die Landeshauptstadt Tirols wird die Optimierte Projektentwicklung (OPE) erläutert. Es handelt sich bei dem Projekt um die Entwicklung eines Stadtteiles im Zentrum von Innsbruck. Die Vorgehensweise ist nicht nur beispielhaft für eine gesunde Stadt(teil)entwicklung, sondern auch richtungsweisend für viele Entwicklungen in ländlichen Regionen.
Vorspannung mit Monolitzen ohne Verbund
Authors: Grad Johann , Kaßner Uwe
Published: May 2004

Die Anwendung der Litzenvorspannung ohne Verbund hat sich ohne Einschränkung in der Praxis bewährt. Den nicht unerheblichen Mehraufwand in der Bearbeitung darf man nicht isoliert betrachten, da er durch die überzeugenden Vorteile wie Rissefreiheit, geringe Durchbiegung der Bauteile usw. auf Dauer mehr als ausgeglichen wird. Im folgenden wird über neue Erkenntnisse und Erfahrungen berichtet. Zudem werden die erweiterten Einsatzgebiete wie die teilweise Vorspannung, Flachdecken, Hohlkörperdecken mit großen Spannweiten und als Quantensprung die vorgespannte Flachdecke aus Stahlfaserbeton behandelt.
Nichtlineare Berechnung alter Bogenbrücken auf Grundlage der neuen Vorschriften
Authors: Bothe Eckard , Henning Jörn , Curbach Manfred , Proske Dirk , Bösche Thomas
Published: May 2004

Der Artikel zeigt die Anwendung der nichtlinearen Berechnung von alten Betonbogenbrücken an einem Beispiel. Dabei erfolgt neben dem Vergleich der Ergebnisse aus linearelastischer Schnittgrößenberechnung und nichtlinearer Berechnung nach DIN‐Fachberichten auch eine Diskussion über die Anwendung der Sicherheitselemente bei diesen Berechnungen. Die Platzierung und Wahl der Sicherheitselemente ist von entscheidender Bedeutung für die Ergebnisse solcher Berechnungen.
On the convergence rate of vanishing viscosity approximations
Authors: Bressan Alberto , Yang Tong
Published: May 2004

Given a strictly hyperbolic, genuinely nonlinear system of conservation laws, we prove the a priori bound ‖u(t, ·) −uϵ(t, ·)‖=O(1)(1 +t) ·$\sqrt{\varepsilon}$|ln ϵ| on the distance between an exact BV solutionuand a viscous approximationuϵ, letting the viscosity coefficient ϵ → 0. In the proof, starting fromuwe construct an approximation of the viscous solutionuϵby taking a mollificationu*$\varphi_{\sqrt{\varepsilon}}$and inserting viscous shock profiles at the locations of finitely many large shocks for each fixed ϵ. Error estimates are then obtained by introducing new Lyapunov functionals that control interactions of shock waves in the same family and also interactions of waves in different families. © 2004 Wiley Periodicals, Inc.
Admissibility of unstable second‐order digital filters with two's complement arithmetic
Authors: Ling Bingo Wing‐Kuen , Ho Charlotte Yuk‐Fan , Tam Peter Kwong‐Shun
Published: May 2004

In this paper, we have extended the existing results on the admissible set of periodic symbolic sequences of a second‐order digital filter with marginally stable system matrix to the unstable case. Based on this result, the initial conditions can be computed using the symbolic sequences. The truncation error of the representation of an initial condition due to the use of a finite number of symbols is studied. Copyright © 2004 John Wiley & Sons, Ltd.
Uniform approximation of time‐invariant non‐linear systems
Authors: Sandberg Irwin W.
Published: May 2004

An Erratum has been published for this article in International Journal of Circuit Theory and Applications 2004; 32(6):633.

It is shown that the elements of a large class of time‐invariant non‐linear input–output maps can be uniformly approximated arbitrarily well, over infinite time intervals, using a certain structure that can be implemented in many ways using, for example, radial basis functions, polynomial functions, piecewise linear functions, sigmoids, or combinations of these functions. For the special case in which these functions are taken to be certain polynomial functions, the input–output map of our structure is a generalized finite Volterra series. Results are given for the case in which inputs and outputs are defined on ℝ. The case in which inputs and outputs are defined on the half‐line ℝ+ is also addressed, and in both cases inputs need not be functions that are continuous. Copyright © 2004 John Wiley & Sons, Ltd.
T cell avidity determines the level of CTL activation
Authors: Hofmann Matthias , Radsak Markus , Rechtsteiner Gerd , Wiemann Katrin , Günder Marc , Bien‐Gräter Ursula , Offringa Rienk , Toes René E.M. , Rammensee Hans‐Georg , Schild Hansjörg
Published: May 2004

To investigate the influence of avidity on T cell activation in vitro and in vivo, we analyzed T cells from St40 and St42 mice, which express the same transgenic TCR specificfor an E1a‐derived epitope of adenovirus type 5 with different expression levels and therefore different avidities. Splenocytes from both strains showed comparable cytolytic activities and requiredidentical peptide concentrations for efficient target cell lysis and up‐regulation of activation markers. However, the kinetics of CD25 up‐regulation were strikingly different: whereas the majorityof the high‐avidity St42 T cells up‐regulated the IL‐2Rα chain within a few hours, low‐avidity St40 T cells expressed only 50% of the CD25 of high‐avidity T cells after 2 days. In addition, low‐avidity T cells proliferated poorly and displayed impaired secretion of IL‐2 and IFN‐γ. Similar results were seen with high‐avidity St42 T cells stimulated with a partial agonistic peptide. Upon adoptive transfer and subsequent immunization with adenovirus, both high‐ and low‐avidity T cells expanded, but St40 T cells were undetectable 10 days after immunization. Our model system now allowsanalysis of whether T cells with identical specificities but different avidities influence each other during activation and homeostatic proliferation.
Efficient and accurate time adaptive multigrid simulations of droplet spreading
Authors: Gaskell P. H. , Jimack P. K. , Sellier M. , Thompson H. M.
Published: May 2004

An efficient full approximation storage (FAS) Multigrid algorithm is used to solve a range of droplet spreading flows modelled as a coupled set of non‐linear lubrication equations. The algorithm is fully implicit and has embedded within it an adaptive time‐stepping scheme that enables the same to be optimized in a controlled manner subject to a specific error tolerance. The method is first validated against a range of analytical and existing numerical predictions commensurate with droplet spreading and then used to simulate a series of new, three‐dimensional flows consisting of droplet motion on substrates containing topographic and wetting heterogeneities. The latter are of particular interest and reveal how droplets can be made to spread preferentially on substrates owing to an interplay between different topographic and surface wetting characteristics. Copyright © 2004 John Wiley & Sons, Ltd.
Identification of neuron‐specific promoters in Ciona intestinalis
Authors: Yoshida Reiko , Sakurai Daisuke , Horie Takeo , Kawakami Isao , Tsuda Motoyuki , Kusakabe Takehiro
Published: May 2004

We isolated 5′ flanking regions of four genes, Ci‐Gαi1, Ci‐arr, Ci‐vAChTP,, and Ci‐vGAT, each of which is expressed in distinct sets of neurons in the central nervous system of the ascidian Ciona intestinalis, and we examined their function by introducing green fluorescent protein (GFP)‐fusion constructs into Ciona embryos. The reporter gene driven by the 5′ flanking region of Ci‐Gαi1, Ci‐arr, and Ci‐vAChTP recapitulated the endogenous gene expression patterns, while that of Ci‐vGAT can drive GFP expression in particular subsets of neurons expressing the endogenous gene. Deletion analysis revealed that the Ci‐Gαi1 promoter consists of multiple regulatory modules controlling the expression in different types of cells. The GFP fluorescence enabled visualization of cell bodies and axons of different sets of neurons in ascidian larvae. These promoters can be a powerful tool for studying molecular mechanisms of neuronal development as well as neuron networks and functions in ascidians. genesis 39:130–140, 2004. © 2004 Wiley‐Liss, Inc.
Minocycline inhibits neuronal death and glial activation induced by β‐amyloid peptide in rat hippocampus
Authors: Ryu Jae K. , Franciosi Sonia , Sattayaprasert Prasongchai , Kim Seung U. , McLarnon James G.
Published: May 2004

Minocycline, a second‐generation tetracycline compound, has been examined as a neuroprotectant in β‐amyloid (Aβ)‐injected rat hippocampus. At 7 days post‐injection, Aβ1‐42 caused a significant loss of granule cell layer neurons (28% reduction) compared to control uninjected hippocampus. Hippocampal injection of Aβ peptide also led to marked gliosis with numbers of microglia (increased by 26‐fold) and immunoreactivity of astrocytes (increased by 11‐fold) relative to control, as determined from immunohistochemical analysis. Intraperitoneal administration of minocycline significantly reduced neuronal loss induced by Aβ1‐42 (by 80%) and also diminished numbers of microglia (by 69%) and astrocytes (by 36%) relative to peptide alone. Peptide injection increased expression of cyclooxygenase‐2 (COX‐2) in most (about 70%) of granule cells, a subset (about 20%) of microglia, but not in astrocytes; in the presence of minocycline, COX‐2 immunostaining was abolished in microglia. The results from this study suggest that minocycline may have efficacy in the treatment of AD. © 2004 Wiley‐Liss, Inc.
Peripherally–derived olfactory ensheathing cells do not promote primary afferent regeneration following dorsal root injury
Authors: Ramer Leanne M. , Richter Miranda W. , Roskams A. Jane , Tetzlaff Wolfram , Ramer Matt S.
Published: May 2004

Olfactory ensheathing cells (OECs) may support axonal regrowth, and thus might be a viable treatment for spinal cord injury (SCI); however, peripherally– derived OECs remain untested in most animal models of SCI. We have transplanted OECs from the lamina propria (LP) of mice expressing green fluorescent protein (GFP) in all cell types into immunosuppressed rats with cervical or lumbar dorsal root injuries. LP‐OECs were deposited into either the dorsal root ganglion (DRG), intact or injured dorsal roots, or the dorsal columns via the dorsal root entry zone (DREZ). LP‐OECs injected into the DRG or dorsal root migrated centripetally, and migration was more extensive in the injured root than in the intact root. These peripherally deposited OECs migrated within the PNS but did not cross the DREZ; similarly, large‐ or small‐caliber primary afferents were not seen to regenerate across the DREZ. LP‐OEC deposition into the dorsal columns via the DREZ resulted in a laminin‐rich injection track: due to the pipette trajectory, this track pierced the glia limitans at the DREZ. OECs migrated centrifugally through this track, but did not traverse the DREZ; axons entered the spinal cord via this track, but were not seen to reenter CNS tissue. We found a preferential association between CGRP‐positive small‐ to medium‐diameter afferents and OEC deposits in injured dorsal roots as well as within the spinal cord. In the cord, OEC deposition resulted in increased angiogenesis and altered astrocyte alignment. These data are the first to demonstrate interactions between sensory axons and peripherally– derived OECs following dorsal root injury. © 2004 Wiley‐Liss, Inc.
Increased NG2+ glial cell proliferation and oligodendrocyte generation in the hypomyelinating mutant shiverer
Authors: Bu Jie , Banki Ali , Wu Qian , Nishiyama Akiko
Published: May 2004

Glial cells that express the NG2 proteoglycan (NG2+ cells) are considered to be oligodendrocyte progenitors (OPCs) in the central nervous system (CNS), based on their ability to give rise to mature oligodendrocytes in vitro. To understand how dysmyelinated conditions influence OPC proliferation and differentiation, we studied proliferation and differentiation of NG2+ OPCs in vivo in the shiverer mutant (shi), which do not form compact myelin due to a deletion in the myelin basic protein gene. Acute bromodeoxyuridine (BrdU) labeling studies revealed a 4‐ to 6‐fold increase in NG2+ cell proliferation in shi spinal cord between postnatal day18 (P18) and P60, and most BrdU+ cells were NG2+ after P18. The increased proliferation was accompanied by a 2‐fold increase in the number of OPCs and oligodendrocytes. Survival studies following a single injection of BrdU at P18 revealed a decline in the number of BrdU+/NG2+ cells with a concomitant increase in the number of BrdU+ oligodendrocytes over time, suggesting that the proliferated NG2+ cells had differentiated into oligodendrocytes. BrdU+ oligodendrocytes were generated over a longer period of time in shi spinal cord and persisted longer in shi than in wild type spinal cord. These findings suggest that new oligodendrocytes continue to be generated in the dysmyelinated shi spinal cord by enhanced proliferation and differentiation of NG2+ oligodendrocyte progenitor cells. © 2004 Wiley‐Liss, Inc.
Expression of T‐type calcium channel splice variants in human glioma
Authors: Latour Isabelle , Louw Deon F. , Beedle Aaron M. , Hamid Jawed , Sutherland Garnette R. , Zamponi Gerald W.
Published: May 2004

In humans, three isoforms of the T‐type (Cav3.1) calcium‐channel α1 subunit have been reported as a result of alternate splicing of exons 25 and 26 in the III–IV linker region (Cav3.1a, Cav3.1b or Cav3.1bc). In the present study, we report that human glioma express Cav3.1 channels in situ, that splicing of these exons is uniquely regulated and that there is expression of a glioma‐specific novel T‐type variant (Cav3.1ac). Seven human glioma samples were collected at surgery, RNA was extracted, and cDNA was produced for RT‐PCR analysis. In addition, three glioma cell lines (U87, U563, and U251N), primary cultures of human fetal astrocytes, as well as adult and fetal human brain cDNA were used. Previously described Cav3.1 splice variants were present in glioma samples, cultured cells and whole brain. Consistent with the literature, our results reveal that in the normal adult brain, Cav3.1a transcripts predominate, while Cav3.1b is mostly fetal‐specific. RT‐PCR results on glioma and glioma cell lines showed that Cav3.1 expression in tumor cells resemble fetal brain expression pattern as Cav3.1bc is predominantly expressed. In addition, we identified a novel splice variant, Cav3.1ac, expressed in three glioma biopsies and one glioma cell line, but not in normal brain or fetal astrocytes. Transient expression of this variant demonstrates that Cav3.1ac displays similar current‐voltage and steady‐state inactivation properties compared with Cav3.1b, but a slower recovery from inactivation. Taken together, our data suggest glioma‐specific Cav3.1 gene regulation, which could possibly contribute to tumor pathogenesis. © 2004 Wiley‐Liss, Inc.
Cognitive impairment and associated risk factors among aged community members
Authors: Yen Yung‐Chieh , Yang Ming‐Jen , Shih Chun‐Hua , Lung For‐Wey
Published: May 2004

Objective

The objective of this paper is to investigate the prevalence of and risk factors associated with cognitive impairment in a community‐dwelling elderly population.

Methods

1000 community residents aged 65–74 years were recruited in the cross‐sectional survey of associated factors of cognitive impairment in southern Taiwan. We employed a multilevel stratified sampling strategy and conducted this interview survey from April to June 2001. The survey questionnaire included background information and the Short Portable Mental Status Questionnaire. The relationship between cognitive impairment and each individual variable in personal attributes and social participation were explored.

Results

Eight hundred and ninety‐four (89.4%) subjects completed the interview and questionnaires. The cognitive impairment rate among all subjects was 4.92%. Of those surveyed, 54.98% were male and 45.02% were female, and the average age was 69.37 (SD 2.73) years. Most survey respondents (72.05%) were married, and 68.90% of the subjects did not participate in any social activities in the last 6 months. Females, those who were illiterate or did not attend school, those who had an average family income below US$860 per month, and persons who did not participate in any social activities had a significantly higher rate of cognitive impairment.

Conclusion

The educational level and participation in social activities were associated with the cognitive impairment among the aged community dwellers. Copyright © 2004 John Wiley & Sons, Ltd.
Solvothermal Morphology Studies: Alkali and Alkaline Earth Molybdates
Authors: Michailovski Alexej , Krumeich Frank , Patzke Greta R.
Published: May 2004

A convenient and systematic solvothermal pathway towards alkali and alkaline‐earth molybdates has been established. The solvothermal treatment of a molybdenum‐based precursor material (yellow molybdic acid, MoO3⋅2 H2O) with ionic additives (alkali or alkaline‐earth halides) provides access to a spectrum of molybdates. Their particle morphology can further be addressed by optimizing the reaction conditions. The resulting products cover a wide scope of sizes and morphologies, ranging from molybdenum oxide fibres with high aspect ratios and nanoscale diameters to millimeter‐sized crystals of novel alkali molybdates. Both anionic and cationic additives exhibit certain synthetic profiles that offer the perspective of turning this approach into a ‘toolbox’ for the tailoring of molybdate‐based materials.
New Antibacterial Diterpenes from Pseudopterogorgia elisabethae
Authors: Ata Athar , Win Hla Y. , Holt David , Holloway Paul , Segstro Edward P. , Jayatilake Gamini S.
Published: May 2004

From the MeOH extract of Pseudopterogorgia elisabethae, collected from the Bahamas, four new diterpenes, elisabethin E (1), elisabethin F (2), pseudopterosin P (3), and pseudopterosin Q (4), were isolated and their structures established with the aid of extensive spectroscopic studies. Compounds 3 and 4 showed antibacterial activity selectively against the Gram‐positive bacteria Streptococcus pyogenes, Staphylococcus aureus, and Enterococcus faecalis.
Cholinesterase‐Inhibiting New Steroidal Alkaloids from Sarcococca hookeriana of Nepalese Origin
Authors: Choudhary M. Iqbal , Devkota Krishna Prasad , Nawaz Sarfraz Ahmad , Shaheen Farzana , Atta‐ur‐Rahman
Published: May 2004

Bioassay‐guided phytochemical investigation of Sarcococca hookeriana has resulted in the isolation and structure elucidation of five new pregnane‐type steroidal alkaloids: (−)‐hookerianamide A (=(2β,3β,4β,20S)‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐16‐ene‐2,4‐diol; 1), (+)‐hookerianamide B (=(2α,3β,4β,20S)‐4‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnan‐2‐ol; 2), (−)‐hookerianamide C (=(2β,3β,20S)‐2‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnane; 3), (−)‐hookerianamine A (=(3β,20S)‐20‐(dimethylamino)‐3‐(methylamino)‐5α‐pregn‐14‐ene; 4), and (+)‐phulchowkiamide A (=(3β,20S)‐20‐(methylamino)‐3‐[(2‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐2‐en‐4‐one; 5). These compounds, as well as the two chemically derived acetyl derivatives 6 and 7, displayed cholinesterase inhibition in a concentration‐dependent manner.
Foetidissimosides C–F, Novel Glycosides from the Roots of Cucurbita foetidissima
Authors: Gaidi Ghezala , Miyamoto Tomofumi , Lerche Holger , Lacaille‐Dubois Marie‐Aleth
Published: May 2004

Two novel echinocystic acid (=(3β,16α)‐3,16‐dihydroxyolean‐12‐en‐28‐oic acid) glycosides, foetidissimosides C (1), and D (2), along with new cucurbitane glycosides, i.e., foetidissimosides E/F (3/4) as an 1 : 1 mixture of the (24R)/(24S) epimers, were obtained from the roots of Cucurbita foetidissima. Their structures were elucidated by means of a combination of homo‐ and heteronuclear 2D‐NMR techniques (COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC), and by FAB‐MS. The new compounds were characterized as (3β,16α)‐28‐{[O‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐xylopyranosyl‐(1→4)‐O‐6‐deoxy‐α‐L‐mannopyranosyl‐(1→2)‐α‐L‐arabinopyranosyl]oxy}‐16‐hydroxy‐28‐oxoolean ‐12‐en‐3‐yl β‐D‐glucopyranosiduronic acid (1), (3β,16α)‐16‐hydroxy‐28‐oxo‐28‐{{O‐β‐D‐xylopyranosyl‐(1→3)‐O‐[β‐D‐xylopyranosyl‐(1→4)]‐O‐6‐deoxy‐α‐L‐mannopyranosyl‐(1→2)‐α‐L‐arabinopyranosyl}oxy}olean‐12‐en‐3‐yl β‐D‐glucopyranosiduronic acid (2), and (3β,9β,10α,11α,24R)‐ and (3β,9β,10α,11α,24S)‐25‐(β‐D‐glucopyranosyloxy)‐9‐methyl‐19‐norlanost‐5‐en‐3‐yl 2‐O‐β‐D‐glucopyranosyl‐β‐D‐glucopyranoside (3 and 4, resp.).
Steroidal Saponins from Disporopsis pernyi
Authors: Yang Qing‐Xiong , Xu Min , Zhang Ying‐Jun , Li Hai‐Zhou , Yang Chong‐Ren
Published: May 2004

Four new steroidal saponins, named disporosides A–D (1–4), corresponding to (3β,25R)‐3‐[(β‐D‐glucopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→6)]‐β‐D‐glucopyranosyl)oxy]‐5β‐spirostan (1), (3β,25R)‐3‐[(β‐D‐glucopyranosyl‐(1→2)‐[6‐O‐hexadecanoyl‐β‐D‐glucopyranosyl‐(1→6)]‐β‐D‐glucopyranosyl)oxy]‐5β‐spirostan (2), (3β,22R,25R)‐26‐[(β‐D‐glucopyranosyl)oxy]‐3‐[(β‐D‐glucopyranosyl‐(1→2)‐β‐D‐glucopyranosyl)oxy]‐5β‐furostan (3), and (3β,22R,25R)‐26‐[(β‐D‐glucopyranosyl)oxy]‐3‐[(β‐D‐glucopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→6)]‐β‐D‐glucopyranosyl)oxy]‐5β‐furostan (4), have been isolated from the fresh rhizomes of Disporopsis pernyi, together with the three known compounds Ys‐I, agavoside B, and (3β,25R)‐3‐[(β‐D‐xylopyranosyl‐(1→3)‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐galactopyranosyl)oxy]‐5α‐spirostan‐12‐one. Their structures were elucidated by spectroscopic analyses, chemical transformations (acid hydrolysis), and comparison with literature data.
Measurement, scaling, and topographic analyses of spatial crop yield and soil water content
Authors: Green Timothy R. , Erskine Robert H.
Published: May 2004

The need to transfer information across a range of space–time scales (i.e. scaling) is coupled with the need to predict variables and processes of interest across landscapes (i.e. distributed simulation). Agricultural landscapes offer a unique set of problems and space–time data availability with the onset of satellite‐based positioning and crop yield monitoring. The present study addresses quantification of the spatial variability of rainfed crop yield and near‐surface soil water at farm field scales using two general methods: (1) geostatistical and fractal analyses; and (2) univariate linear regression using topographic attributes as explanatory variables. These methods are applied to 2 years of crop yield data from three fields in eastern Colorado, USA, and to soil‐water content (depth‐averaged over the top 30 cm) in one of these fields. Method 1 is useful for scaling each variable, and variogram shapes and their associated fractal dimensions of crop yield are related to those of topographic attributes. A new measure of fractal anisotropy is introduced and estimated from field data. Method 2 takes advantage of empirical and process knowledge of topographic controls on water movement and microenvironments. Topographic attributes, estimated from a digital elevation model at some scale (10 m by 10 m spacing here), help explain the spatial variability in crop yield. The topographic wetness index, for example, explained from 38 to 48% of the spatial variance in 1997 wheat yield. Soil water displays more random spatial variability, and its dynamic nature makes it difficult to predict in both space and time. Despite such variability, spatial structure is evident and can be approximated by simple fractals out to lag distances of about 450 m. In summary, these data and spatial analyses provide a basis and motivation for estimating the fractal behaviour, spatial statistics, and distributed patterns of crop yield from landscape topographic information. Copyright © 2004 John Wiley & Sons, Ltd.
A general test for time dependence in parameters
Authors: Becker Ralf , Enders Walter , Hurn Stan
Published: May 2004

A new test for time‐dependent parameters is proposed. The Trig‐test is based on a trigonometric expansion to approximate the unknown functional form of the variation in the parameters concerned. It is shown to have the correct empirical size and excellent power to detect structural breaks and stochastic parameter variation. The appropriate use of the Trig‐test is demonstrated by testing for structural breaks in the US inflation rate. The test detects a statistically significant increase in the US inflation rate beginning in the early 1970s and lasting through to the early 1980s. Copyright © 2004 John Wiley & Sons, Ltd.
The effects of subjective survival on retirement and Social Security claiming
Authors: Hurd Michael D. , Smith James P. , Zissimopoulos Julie M.
Published: May 2004

According to the life‐cycle model, mortality risk will influence both retirement and the desire to annuitize wealth. We estimate the effect of subjective survival probabilities on retirement and on the claiming of Social Security benefits because delayed claiming is equivalent to the purchase of additional Social Security annuities. We find that those with very low subjective probabilities of survival retire earlier and claim earlier than those with higher subjective probabilities, but the effects are not large. The great majority of workers claim as soon as they are eligible. Copyright © 2004 John Wiley & Sons, Ltd.
Technical note: A toy as tool: A low‐cost image analysis system for the evaluation of tumor size in experimental small animal models
Authors: Brockmann Marc Alexander , Ulmer Stephan , Lamszus Katrin , Giese Alf , Petersen Dirk
Published: May 2004

Image analysis systems are an essential tool in measurements of size of intraparenchymal tumors or lesions in experimental small animal models. Conventional image analysis systems are relatively expensive. We therefore compared the performance of a professional image analysis system with an inexpensive setup by evaluating tumor size in an orthotopic glioma mouse model. The maximum cross‐sectional tumor area of H&E stained brain‐slides of two groups of mice (treatment and control group) was measured by two independent investigators using a professional image analysis system (Leica DM IRB microscope) with the Leica Quantimet 500c software, and a low‐cost‐system (Intel QX3 microscope) with a non‐commercial image analysis software. Mean tumor volumes were calculated and the results from each of the image analysis systems, investigators, and treatment effects were compared. The tumor volumes as measured with the low‐cost and the professional system differed between −3.7 and +7.5% (P = 0.69–0.99). Measurements made by investigator A and B differed between −7.0 and +3.9% (P = 0.69–0.88). Treatment in all cases significantly reduced the tumor volume between 58.4 and 62.7% (P = 0.0002 or 0.0003), regardless of the investigator or the used image analysis system. We therefore conclude that the QX3 low‐cost microscope in combination with a non‐commercial image‐analysis software represents an inexpensive solution to reliably analyze the size of regions of interest, if they provide a sufficient contrast. However, the low‐cost setup due to its low resolution definitely limits a detailed analysis of histologic features. Microsc. Res. Tech. 63:306–309, 2004. © 2004 Wiley‐Liss, Inc.
Electron energy loss spectroscopy for analysis of inhaled ultrafine particles in rat lungs
Authors: Kapp Nadine , Kreyling Wolfgang , Schulz Holger , Hof Vinzenz Im , Gehr Peter , Semmler Manuela , Geiser Marianne
Published: May 2004

Epidemiologic studies have associated cardiovascular morbidity and mortality with ambient particulate air pollution. Particles smaller than 100 nm in diameter (ultrafine particles) are present in the urban atmosphere in very high numbers yet at very low mass concentration. Organs beyond the lungs are considered as targets for inhaled ultrafine particles, whereby the route of particle translocation deeper into the lungs is unclear. Five rats were exposed to aerosols of ultrafine titanium dioxide particles of a count median diameter of 22 nm (geometric standard deviation, GSD 1.7) for 1 hour. The lungs were fixed by intravascular perfusion of fixatives immediately thereafter. TiO2 particles in probes of the aerosol as well as in systematic tissue samples were analyzed with a LEO 912 transmission electron microscope equipped with an energy filter for elemental microanalysis. The characteristic energy loss spectra were obtained by fast spectrum acquisition. Aerosol particles as well as those in the lung tissue were unambiguously identified by electron energy loss spectroscopy. Particles were mainly found as small clusters with a rounded shape. Seven percent of the particles in the lung tissue had a needle‐like shape. The size distribution of the cluster profiles in the tissue had a count median diameter of 29 nm (GSD 1.7), which indicates no severe clustering or reshaping of the originally inhaled particles. Electron energy loss spectroscopy and related analytical methods were found to be suitable to identify and localize ultrafine titanium dioxide particles within chemically fixed and resin‐embedded lung tissue. Microsc. Res. Tech. 63:298–305, 2004. © 2004 Wiley‐Liss, Inc.
Bipartite anti‐Ramsey numbers of cycles
Authors: Axenovich Maria , Jiang Tao , Kündgen André
Published: May 2004

We determine the maximum number of colors in a coloring of the edges of Km,n such that every cycle of length 2k contains at least two edges of the same color. One of our main tools is a result on generalized path covers in balanced bipartite graphs. For positive integers q≤ a, let g(a,q) be the maximum number of edges in a spanning subgraph G of Ka,a such that the minimum number of vertex‐disjoint even paths and pairs of vertices from distinct partite sets needed to cover V(G) is q. We prove that g(a,q) = a2 − aq + max {a, 2q − 2}. © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 9–28, 2004
Pelvic exenteration and sphincter preservation: An analysis of 96 cases
Authors: Oliveira Poletto Antonio Henrique , Lopes Ademar , Carvalho André Lopes , Ribeiro Edson Augusto , da Costa Vieira René Aloísio , Rossi Benedito Mauro , Aguiar Samuel , Guimarães Gustavo Cardoso , Ferreira Fabio de Oliveira , Nakagawa Wilson Toshihiko
Published: May 2004

Background

Pelvic exenteration (PE) is characterized by its technical complexity and morbidity rate. Appropriate patient selection prior to the operation allows for more conservative surgeries, preserving sphincters, and continent reconstruction of the intestinal and urinary tract, contributing to better results.

Methods

Between 1980 and 2000, 96 PE were performed. Factors related to sphincter preservation as well as factors associated to prognosis were respectively analyzed.

Results

Of the 96 PE, at least one sphincter in 36 patients was preserved (37.5%). In the 1990s, the sphincter preservation rate was significantly higher than in the 1980s (47.6 vs. 18.2%) (P = 0.005). More serious complications happened in 19.8% of the patients and the post‐operative mortality rate was 15.6%. The post‐operative complication rate was not influenced by sphincter preservation (P = 0.276). In nine patients, the resection margins were compromised microscopically (R1) and in five patients, there were macroscopically compromised (R2). The resection margins were not influenced by the type of surgery (P = 0.104), nor by the preservation of sphincters (P = 0.881). Twenty‐three patients experienced relapses, 13 being local, eight distant, and two local and distant. Disease free survival at 5 years was 40.5%, and the primary site of the tumor was a factor associated to differences in disease free survival (P = 0.027). Overall 5‐year survival was 41.9% and was significantly associated to the number of organs compromised (P = 0.040) and sphincter preservation (P = 0.026). Patients who were submitted to R0 type resection had a median survival of 40.9 months, while R1 and R2 type resections had a median 21.2 month survival.

Conclusions

The appropriate pre‐operative selection of the patient and rigorous oncological criteria permit PE to be performed while preserving the sphincters in selected cases, without harming survival rates. J. Surg. Oncol. 2004;86:122–127. © 2004 Wiley‐Liss, Inc.
Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH2‐Mediated Polycondensation Reaction
Authors: Ding Jianfu , Day Michael , Robertson Gilles P. , Roovers Jacques
Published: May 2004

Summary: A new reaction procedure has been developed for the polycondensation of hexafluorobisphenol A (6F‐BPA) with bis(pentafluorophenyl) ketone (BPK) in dimethylacetamide (DMAc). In this reaction, CaH2 has been used as a base to facilitate the formation of the phenolate; an alkali metal fluoride was used as a catalyst. Unlike the conventional polycondensation reactions, this procedure avoided producing water during the reaction, and hence, azeotropic distillation with the assistant of a low‐polar co‐solvent is not required. This improvement maintains the high polarity of the reaction medium; consequently, the selectivity of the reaction at the para‐position of BPK is significantly enhanced and polymers with high molecular weights ($\overline M _{\rm n}$ ca. 30 000 Da) can be obtained with very low branching contents (less than 3 mol‐%) and free of any cross‐linked gel particles. In addition to avoiding the formation of water in the reaction, the use of CaH2 also reduced the concentration of the fluoride ion in the solution. These effects minimize chain degradation reactions such as hydrolysis. The use of CaO instead of CaH2 for this reaction produces similar effects. In the case of CaO, traces of water can be introduced into the reaction. The presence of trace amounts of water increases the polycondensation rate, probably due to the enhanced ionization of the phenolate. However, it also causes a hydrolysis of polymer chains, resulting in the elimination of the ketone group in the polymer backbone. Fortunately, this side reaction is highly water and temperature dependent, and can be efficiently prevented by using CaH2 or conducting the reaction at a lower temperature (<65 °C).

CaH2‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone).

image

CaH2‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone).
Exact solutions of space–time dependent non‐linear Schrödinger equations
Authors: Ruan Hang‐yu , Li Hui‐jun , Chen Yi‐xin
Published: May 2004

Using a general symmetry approach we establish transformations between different non‐linear space–time dependent evolution equations of Schrödinger type and their respective solutions. As a special case we study the transformation of the standard non‐linear Schrödinger equation (NLS)‐equation to a NLS‐equation with a dispersion coefficient which decreases exponentially with increasing distance along the fiber. By this transformation we construct from well known solutions of the standard NLS‐equation some new exact solutions of the NLS‐equation with dispersion. Copyright 2004 John Wiley & Sons, Ltd.
Exact controllability for quasilinear hyperbolic systems and its application to unsteady flows in a network of open canals
Authors: Tatsien Li
Published: May 2004

In this paper we establish the exact boundary controllability for quasilinear hyperbolic systems with interface conditions. As an application, we get the exact boundary controllability of unsteady flows in a string‐like network of open canals. Copyright © 2004 John Wiley & Sons, Ltd.
On the existence of steady flows of a Navier–Stokes liquid around a moving rigid body
Authors: Silvestre Ana Leonor
Published: May 2004

We prove the existence of a strong solution to the three‐dimensional steady Navier–Stokes equations in the exterior of an obstacle undergoing a rigid motion. Unlike the classical exterior problem for the Navier–Stokes equations, that only takes into account the translational motion of the obstacle, is this case, the obstacle can also rotate. Assuming the total flux of the velocity field through the boundary to be sufficiently small, we first construct approximating solutions in bounded regions ΩR = Ω∩ {x ∈ ℝ3:∣x∣< R} invading the liquid domain Ω. A set of estimates independent of R are shown to hold for the approximating solutions which allows to obtain a strong solution by taking the limit R→∞. Copyright © 2004 John Wiley & Sons, Ltd.
On a resolvent problem for the linearized system from the dynamical system describing the compressible viscous fluid motion
Authors: Shibata Yoshihiro , Tanaka Koumei
Published: May 2004

The linearized initial boundary value problem describing the motion of the viscous compressible fluid is studied under Dirichlet zero condition in bounded and unbounded domains. The resolvent estimate for the corresponding operator is proved in the Lp framework and the sharp inner estimate of the resolvent set is obtained. Copyright © 2004 John Wiley Sons, Ltd.
1‐(2‐pyrimidinyl)‐piperazine, a buspirone metabolite, modulates bladder function in the anesthetized rat
Authors: Myers Robert A. , Plym Mary Jane , Signor Laura J. , Lodge Nicholas J.
Published: May 2004

Aims

To examine the effects of 1‐(2‐pyrimidinyl)‐piperazine (1‐PP), a buspirone metabolite, on bladder function in vivo.

Methods

Micturition reflexes in the rat were evaluated in two models of bladder function; a constant infusion model employing 0.5% acetic acid and an isovolumic model.

Results

In the constant infusion model, 1‐PP (0.14–1.32 mg/kg) dose‐dependently and significantly decreased the number of bladder contractions measured during a 30 min recording period, with little effect on the pressure developed during each contraction. 1‐PP is an α2‐adrenergic receptor antagonist. The α2 antagonists BRL44408 (α2A vs. α2B selective; 0.3 and 1 mg/kg), imiloxan (α2B vs. α2A selective; 1 mg/kg), and yohimbine (non‐subtype selective; 1 mg/kg; but not 0.3 mg/kg) also significantly reduced the number of contractions. Vehicle was without effect. In the isovolumic model, 1‐PP (0.03–1.0 mg/kg) produced a dose‐dependent and significant reduction in the number of bladder contractions recorded during a 15 min assessment period, with the maximum effect observed at 0.3 mg/kg. 1‐PP had little effect on blood pressure; the only effect was observed at the highest dose (1 mg/kg) where it produced a transient 17% decrease in pressure. Cromakalim and tolterodine served as comparitors in all studies.

Conclusions

1‐PP decreased the number of bladder contractions evoked by the micturition reflex at doses that had little effect on either the pressure developed during each bladd er contraction or on blood pressure. The effects of 1‐PP are likely mediated primarily by α2 receptor antagonism. © 2004 Wiley‐Liss, Inc.
Some recent contributions to network optimization
Authors: Ben‐Ameur Walid , Gouveia Luis
Published: May 2004

This report highlights some recent contributions to network optimization based on papers presented at the first International Network Optimization Conference (INOC'2003) held in Evry‐Paris, France. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(1), 27–30 2004