bluuebunny/crossref_metadata_2025_split huggingface dataset:
ColonialDifferentiation in
Streptomyces
coelicolor
Depends on Translation of a SpecificCodon within the
adpA
Gene
Authors: Nguyen Kien T. , Tenor Jennifer , Stettler Hansruedi , Nguyen Lieu T. , Nguyen Liem D. , Thompson Charles J. 
Published: December 2003

ABSTRACT

We
identified
adpA
as an
araC
-like regulatory gene
needed for colonial morphogenesis in
Streptomyces
coelicolor
and showed that its activity depended on a unique
TTA triplet corresponding to the leucyl-tRNA gene (
bldA
).
These findings partially explained the dependence of aerial mycelium
formation on a rare tRNA that is postulated to have developmental
control
functions.
Initial accumulation of platelets during arterial thrombus formation in vivo is inhibited by elevation of basal cAMP levels
Authors: Sim Derek S. , Merrill-Skoloff Glenn , Furie Barbara C. , Furie Bruce , Flaumenhaft Robert 
Published: December 2003

AbstractPlatelet accumulation at sites of vascular injury is the primary event in arterial thrombosis. Initial platelet accrual into thrombi is mediated by interactions of platelet adhesion receptors with ligands on the injured endothelium or in the sub-endothelial matrix. The role of intracellular signals in initial platelet accumulation at sites of endothelial injury, however, is the subject of debate. We have used a newly discovered inhibitor of phosphodiesterase 3A (PDE3A) and the well-characterized PDE3A inhibitor, cilostazol, to modulate 3′,5′-cyclic adenosine monophosphate (cAMP) levels in an in vivo model that enables the kinetic analysis of platelet accumulation. These studies demonstrate that elevation of basal cAMP levels results in an overall decline in platelet accumulation at the site of vascular injury. In particular, the initial rate of accumulation of platelets is inhibited by elevation of cAMP. Analysis of the kinetics of individual platelets at injury sites using intravital microscopy demonstrates that cAMP directs the rate at which platelets attach to and detach from thrombi. These studies demonstrate that cAMP in circulating platelets controls attachment to and detachment from sites of arteriolar injury. Thus, the status of the intracellular signaling machinery prior to engagement of platelet receptors influences the rate of platelet accumulation during thrombus formation.
A novel mechanism for imatinib mesylate–induced cell death of BCR-ABL–positive human leukemic cells: caspase-independent, necrosis-like programmed cell death mediated by serine protease activity
Authors: Okada Masayuki , Adachi Souichi , Imai Tsuyoshi , Watanabe Ken-ichiro , Toyokuni Shin-ya , Ueno Masaki , Zervos Antonis S. , Kroemer Guido , Nakahata Tatsutoshi 
Published: December 2003

AbstractCaspase-independent programmed cell death can exhibit either an apoptosis-like or a necrosis-like morphology. The ABL kinase inhibitor, imatinib mesylate, has been reported to induce apoptosis of BCR-ABL–positive cells in a caspase-dependent fashion. We investigated whether caspases alone were the mediators of imatinib mesylate–induced cell death. In contrast to previous reports, we found that a broad caspase inhibitor, zVAD-fmk, failed to prevent the death of imatinib mesylate–treated BCR-ABL–positive human leukemic cells. Moreover, zVAD-fmk–preincubated, imatinib mesylate–treated cells exhibited a necrosis-like morphology characterized by cellular pyknosis, cytoplasmic vacuolization, and the absence of nuclear signs of apoptosis. These cells manifested a loss of the mitochondrial transmembrane potential, indicating the mitochondrial involvement in this caspase-independent necrosis. We excluded the participation of several mitochondrial factors possibly involved in caspase-independent cell death such as apoptosis-inducing factor, endonuclease G, and reactive oxygen species. However, we observed the mitochondrial release of the serine protease Omi/HtrA2 into the cytosol of the cells treated with imatinib mesylate or zVAD-fmk plus imatinib mesylate. Furthermore, serine protease inhibitors prevented the caspase-independent necrosis. Taken together, our results suggest that imatinib mesylate induces a caspase-independent, necrosis-like programmed cell death mediated by the serine protease activity of Omi/HtrA2.
Homer-3 regulates activation of serum response element in T cells via its EVH1 domain
Authors: Ishiguro Kazuhiro , Xavier Ramnik 
Published: December 2003

Abstract
Drosophila enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) homology 1 (EVH1) domain proteins regulate signal transduction at the neuronal and immunologic synapse. Despite shared cell biologic machinery at these synapses, the regulation of client proteins that transmit synaptic activity to the nucleus is likely to be different. Homer-3, a member of the EVH1 family, is expressed in the thymus, suggesting a role for this protein in T-cell signal transduction. Upon T-cell receptor (TCR) engagement, Homer-3 was recruited to the contact area of Jurkat cells to anti-CD3 and CD28 antibody–coated beads prior to actin accumulation and was subsequently translocated into the nucleus. Overexpression of Homer-3 reduced transcriptional activation via the serum response element (SRE) in response to anti-CD3 antibody, phorbol ester, or dominant active Ha-Ras. Consistent with these results, knockdown of Homer-3 increased SRE activation. Homer-3 coprecipitated with CCAAT/enhancer binding protein β (C/EBPβ), one of the transcription factors that binds to the SRE and has a consensus motif binding to EVH1 domain. Moreover, Homer-3 and its EVH1 domain fragment reduced transcriptional activation of C/EBPβ. These findings suggest that Homer-3 may be involved in the regulation of SRE activation in T cells via interaction between its EVH1 domain and C/EBPβ.
Purα, a Single-Stranded Deoxyribonucleic Acid Binding Protein, Augments Placental Lactogen Gene Transcription
Authors: Limesand Sean W. , Jeckel Kimberly M. , Anthony Russell V. 
Published: December 2003

AbstractPlacental lactogen (PL) is thought to alter maternal metabolism to increase the pool of nutrients available for the fetus and to stimulate fetal nutrient uptake. The ovine (o) PL gene is expressed in chorionic binucleate cells (oBNC) and cis-elements located within the proximal promoter (−124 to +16 bp) are capable of trophoblast-specific expression in human (BeWo) and rat (Rcho-1) choriocarcinoma cells. Protein-DNA interactions were identified with oBNC nuclear extracts, and mutational analysis of these regions revealed a previously undefined cis-element from −102/−123 bp that enhances promoter activity in BeWo cells but not Rcho-1 cells. Characterization of this region identified the nucleotide sequence CCAGCA (−105/−110; o110) as the responsible cis-acting element. Southwestern analysis with this element identified a binding protein with an apparent Mr of approximately 41,000. Expression screening of an ovine placental cDNA library identified six homologous cDNAs, which shared identity with human (97%) and mouse (95%) Purα, a single-stranded DNA binding protein. The Purα-o110 interaction was confirmed by electrophoretic mobility-supershift assays with oBNC and BeWo extracts but was absent with Rcho-1 extracts. Furthermore, overexpression of ovine Purα enhanced transactivation of the oPL gene proximal promoter in both choriocarcinoma cell lines through this novel cis-element. This study identified a previously undefined cis-element, which interacts with Purα to augment PL gene transcription.
Modellierung der mittleren Phase der HIV-Infektion unter Medikation (Modelling the Middle Phase of HIV Infection during Medication)
Authors: Lichtenberg Gerwald , Nolde Kristian , Riedel Uta , Schwank Alexander , Stellbrink Hans-Jürgen 
Published: December 2003

Abstract
Der Beitrag stellt einen Ansatz zur Modellierung der mittleren Phase der HIV-Infektion unter Medikation vor. Das erstellte Modell beschreibt dabei die Konzentrationen von Viren, gesunden und infizierten CD4+-T-Zellen und CD8+-T-Zellen im Blut. Berücksichtigt werden neben den Sterbe-, Geburts- und Infektionsprozessen auch die Infektionshemmung durch Medikamente sowie Regelungsprozesse für die Zellkonzentrationen des Immunsystems. Der grundlegende Unterschied zwischen einer HIV-Infektion und anderen Viruserkrankungen kann dadurch als Unterschied in der internen Kopplungstruktur interpretiert werden. Die Parameter des Modells wurden anhand klinischer Messdaten geschätzt. Eine Möglichkeit zur Vorhersage der Medikamentenwirkung aufgrund der Messung der initialen Zellkonzentrationen vor Therapiebeginn wird vorgestellt.
Beziehungen zwischen qualitativen dynamischen Modellen und dem Frobenius-Perron-Operator (Connections between Qualitative Dynamical Models and the Frobenius-Perron Operator)
Authors: Lunze Jan , Schröder Jochen 
Published: December 2003

AbstractThe paper concerns the discrete-event behaviour of quantised systems. As the state can only be measured through a quantiser, trajectory bundles have to be considered, which can be represented for autonomous systems by the Frobenius-Perron operator and for systems with inputs by the Foias operator. These operators can be written down in an explicit form only for a restricted class of systems. Hence, discrete approximations of these operators are used in systems analysis. The paper shows that these approximations are identical to the state transition functions of stochastic automata, which are used in process diagnosis and verification. This interesting connection between results from mathematical systems theory and the literature on hybrid control systems makes it possible to combine the results obtained in both fields.
Internetbasierte Laborexperimente für die regelungstechnische Ausbildung (Internet-based Laboratory Experiments for Automatic Control Engineering Education)
Authors: Roth Hubert , Rösch Otto J. , Prusak Alexander 
Published: December 2003

Abstract
Die Fernsteuerung von Laborexperimenten in Verbindung mit didaktisch konzipierten Lerneinheiten ist Gegenstand dieses Artikels. Dabei wird die Entwicklung von multimedialen Plattformen erläutert, welche aus Lerneinheiten in Verbindung mit der Fernsteuerung realer Hardware bestehen. Die angebotenen Laborexperimente sind über das Internet fernsteuerbar und dienen der Ingenieursausbildung in der Regelungs- und Steuerungstechnik sowie der Mechatronik.
Eine Anwendung von Knowledge Discovery in Databases im eLearning (An Application of Knowledge Discovery in Databases in eLearning)
Authors: Köster Frank , Grawunder Marco 
Published: December 2003

Zusammenfassung
Dieser Artikel behandelt die Entwicklung eines Assistenzsystems für Nutzer elektronischer Lehr-/Lernmaterialien (eLLM). Dabei wird das simulatorbasierte Pilotentraining als konkrete Beispielanwendung betrachtet. In diesem Kontext wird insbesondere die mögliche Isolation von Nutzern eLLM als Problem hervorgehoben. Arbeiten zu Tutoriellen Systemen, Virtuellen Lerngemeinschaften, Lernarrangements o.Ä. diskutieren ein facettenreiches Instrumentarium zur Behandlung dieses Problems und prägen eben-so unseren Ansatz. Dieser zielt darauf ab, eine tutorielle Unterstützung sowie Aufgaben zur Bildung/Festigung virtueller Lerngemeinschaften an spezielle Softwarekomponenten (Agenten) zu delegieren, die den Nutzern uneingeschränkt als Assistenten zur Verfügung stehen. Bei der Implementierung der Verhaltensgrundlage dieser Agenten verfolgen wir einen datengetriebenen Zugang, wobei Methoden des Knowledge Discovery in Databases (KDD) zur Anwendung kommen. Die in diesem Zusammenhang erzielten Ergebnisse stellen den Schwerpunkt dieses Artikels dar. Sie umfassen Werkzeuge zum KDD sowie Resultate ihrer Anwendung.
Substrate Infiltration and Histological Fixatives Affect the In Situ Localisation of β‐Glucuronidase Activity in Transgenic Tissues
Authors: Preťová A. , Obert B. , Wetzstein H. Y. 
Published: December 2003

AbstractThe β‐glucuronidase (GUS) gene is a widely used reporter gene in transgenic research. This study shows that although histochemical localisation of GUS activity may be very specific, differences in incubation conditions and tissue status can lead to artificial localisations that are independent of gene activity. The objective of the current studies was to evaluate the factors that affect the in‐situ localisation of β‐glucuronidase using transgenic tobacco plants as model tissues. The aspects considered include tissue size as well as and the addition of surfactants, vacuum infiltration and chemical fixatives. Transgenic tobacco plants exhibited variable staining patterns dependent on the size of tissue assayed and the treatments that affected the infiltration of substrate. A gradient of blue staining was observed in larger tissue pieces (10 mm2), where staining in central areas was light blue in contrast to edges, which stained deep indigo. More intense staining was associated with peripheral cell layers and regions adjacent to leaf veins. Thinner tissue strips incubated under similar conditions exhibited intense and even X‐Gluc staining. Addition of Triton X‐100 (1%) surfactant and vacuum infiltration (2 min) produced considerably quicker and more uniform staining (intense and consistent indigo blue colour) of the examined tissue after a 4 to 6‐h incubation. Chemical fixation of tissues before GUS assay resulted in quantitative and histochemical differences in enzyme activity that were dependent on the fixative type and duration. Quantitative measurements using the MUG fluorometric assay showed that Histochoice™ provided the highest retention of GUS activity, maintaining more than 80 and 50% of the activity after fixation for 15 and 30 min, respectively. Activity in decreasing order was obtained with paraformaldehyde, glutaraldehyde, ethanol and FAA. GUS activity was affected not only by the type of fixative, but also by the duration of fixation with longer fixation producing lower GUS activity. From the experiments performed it can be concluded that those treatments that enhance substrate penetration, i.e., the addition of surfactant and vacuum infiltration, improve the consistency and speed of X‐Gluc staining.
Czochralskis schöpferischer Fehlgriff: ein Meilenstein auf dem Weg in die Gigabit‐Ära
Authors: Evers Jürgen , Klüfers Peter , Staudigl Rudolf , Stallhofer Peter 
Published: December 2003

AbstractDer schnelle Wandel in Industrie, Wissenschaft und Gesellschaft beruht auf der rasanten Entwicklung der Mikroelektronik. Auch das tägliche Leben ist von dieser Entwicklung geprägt: Man denke nur an das Mobiltelefon oder die Chip‐Karte. Basismaterial für die Mikroelektronik sind Einkristalle aus Silicium mit hoher Reinheit und nahezu perfektem Kristallbau. Heute werden 95 % der Weltproduktion an einkristallinem Silicium nach dem Verfahren hergestellt, das der Pole Jan Czochralski 1916 entdeckte.Die Siliciumeinkristalle, die heute produziert werden, sind etwa 2 m lang, haben einen Durchmesser von 300 mm und wiegen 265 kg. Durch Anlegen von Magnetfeldern während des Kristallziehens sind große Fortschritte erzielt worden. Forschung und Entwicklung haben gezeigt, dass neben der weiteren Vergrößerung des Einkristalldurchmessers auch dem Defekt‐Engineering, der Beherrschung der vielfältigen temperaturabhängigen Reaktionen von Kristallbaufehlern, entscheidende Bedeutung zukommt.
Synthesis and characterization of isotopically enriched methylmercury (CH3201Hg+)
Authors: Mizanur Rahman G. M. , Skip Kingston H. M. , Bhandari Sandeep 
Published: December 2003

AbstractA simple procedure for the synthesis of an important standard, isotopically enriched methylmercury, which is not commercially available, has been established successfully. The isotopically enriched standard synthesized is utilized in conventional isotope dilution mass spectrometry (IDMS), as well as in speciated IDMS (SIDMS), for determination of the true concentration of methylmercury in environmental samples. The CH3201Hg+ standard has been synthesized from commercially available 201HgO and tetramethyltin. The synthesis time required is 1 h at 60°C. The product is highly pure, yielding more than 90% as 201Hg in CH3201Hg+. Hazardous dimethylmercury does not occur during this synthesis procedure. The product synthesized was analyzed using high‐performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP‐MS) and ICP‐MS alone in order to determine its concentration, isotopic composition and purity. The stability of the product was also evaluated for over 6 months and found to be stable at 4°C in the dark. The isotopically enriched methylmercury synthesized can be used in SIDMS and IDMS analyses as a standard. Copyright © 2003 John Wiley & Sons, Ltd.
Diorganotin(IV) complexes of D‐galacturonic acid: solid‐state and solution‐phase structural study
Authors: Bertazzi N. , Bruschetta G. , Casella G. , Pellerito L. , Rotondo E. , Scopelliti M. 
Published: December 2003

AbstractThree diorganotin(IV) complexes of D‐galacturonic acid (H2GalA; R = Me, n‐Bu, Ph), two of which are new derivatives (R = Me, Ph), have been synthesized and their solid‐state and solution‐phase investigated by IR, Mössbauer, 1H, 13C and 119Sn NMR spectroscopy. The FTIR data suggest that H2GalA, in the dialkyltin derivatives, behaves as a dianionic ligand, coordinating the tin(IV) atom through an ester‐type carboxylate and deprotonated alcoholic hydroxo groups, whereas a bridging carboxylate occurs in the diphenyltin(IV) complex. Octahedral and trigonal bipyramidal local geometries on tin(IV) atoms are proposed for dialkyltin(IV)GalA and diphenyltin(IV)GalA complexes respectively on the basis of Mössbauer spectroscopy. In D2O solution, R2Sn(IV) moieties seem to be mainly coordinated by the GalA2− in the β‐furanosidic (β‐GalfA2−) form, involving the β‐furanosidic ring in rotational equilibrium. However, the α‐furanosidic (α‐GalfA2−), α‐pyranosidic (α‐GalpA2−) and the β‐pyranosidic (β‐GalpA2−) isomers are also involved in the coordination upon the tin atom to a minor extent. In DMSO‐d6 solution, R2Sn(IV) moieties are coordinated almost entirely by the GalA2− in the β‐furanosidic form. Copyright © 2003 John Wiley & Sons, Ltd.
Extremes of deterministic sub‐sampled moving averages with heavy‐tailed innovations
Authors: Scotto M. , Ferreira H. 
Published: December 2003

AbstractLet {Xk}k⩾1 be a strictly stationary time series. For a strictly increasing sampling function g:ℕ→ℕ define Yk=Xg(k) as the deterministic sub‐sampled time series. In this paper, the extreme value theory of {Yk} is studied when Xk has representation as a moving average driven by heavy‐tailed innovations. Under mild conditions, convergence results for a sequence of point processes based on {Yk} are proved and extremal properties of the deterministic sub‐sampled time series are derived. In particular, we obtain the limiting distribution of the maximum and the corresponding extremal index. Copyright © 2003 John Wiley & Sons, Ltd.
Dual‐ and triple‐mode matrix approximation and regression modelling
Authors: Lipovetsky Stan , Michael Conklin W. 
Published: December 2003

AbstractWe propose a dual‐ and triple‐mode least squares for matrix approximation. This technique applied to the singular value decomposition produces the classical solution with a new interpretation. Applied to regression modelling, this approach corresponds to a regularized objective and yields a new solution with properties of a ridge regression. The results for regression are robust and suggest a convenient tool for the analysis and interpretation of the model coefficients. Numerical results are given for a marketing research data set. Copyright © 2003 John Wiley & Sons, Ltd.
The discounting of ambiguous information in economic decision making
Authors: van Dijk Eric , Zeelenberg Marcel 
Published: December 2003

AbstractIn three experimental studies we investigated how decision makers respond to ambiguous information about costs and benefits. In Experiment 1, we studied the effect of ambiguity about prior costs. Experiments 2 and 3 focused on the effect of ambiguity about future outcomes. The collective results of the three studies suggest that decision makers discount ambiguous information. The findings are related to insights on the disjunction effect, the sunk cost effect, transaction decoupling, and ambiguity aversion. Copyright © 2003 John Wiley & Sons, Ltd.
A simple and simultaneous determination of acyclovir and ganciclovir in human plasma by high‐performance liquid chromatography
Authors: Teshima Daisuke , Otsubo Kaori , Yoshida Tsuneko , Itoh Yoshinori , Oishi Ryozo 
Published: December 2003

AbstractA simple high‐performance liquid chromatographic method was developed for the simultaneous determination of the therapeutic levels of acyclovir and ganciclovir in human plasma. After precipitation of plasma proteins with 6% perchloric acid, acyclovir and ganciclovir were simultaneously determined by reversed‐phase chromatography with spectophotometric detection at 254 nm. The peak heights for acyclovir and ganciclovir were linearly related to their concentrations ranging from 0.063 to 2.080 µg/mL. The recovery was 100.48–102.84% for acyclovir and 99.26–103.07% for ganciclovir. The intra‐ and inter‐day relative standard deviation values were in the range 0.186–8.703% for acyclovir and 0.137–6.424% for ganciclovir. The detection limits for both compounds were 0.01 µg/mL determined as the signal‐to‐noise ratio of 3. The present method is applicable to therapeutic monitoring during antiviral medication. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of paeonol in rat plasma by high‐performance liquid chromatography and its application to pharmacokinetic studies following oral administration of Moutan cortex decoction
Authors: Wu Xinan , Chen Hongli , Chen Xingguo , Hu Zhide 
Published: December 2003

AbstractQuantiﬁcation of paeonol, the principal bioactive component of Moutan cortex, in rat plasma following oral administration of Moutan cortex decoction was achieved by using a simple and sensitive high‐performance liquid chromatographic method. The calibration curves for paeonol were linear in both the low (25–200 ng/mL) and the high concentration range (200–4000 ng/mL) with r2 values of 0.9928 and 0.9993, respectively. The coefﬁcients of variation of intra‐ and inter‐day assays were 14.36, 6.52, 1.76, 1.25, 5.36, 3.30 and 1.42% and 12.70, 1.19, 2.98, 1.91, 1.75, 1.78 and 0.96% at concentrations of 25, 50, 100, 200, 500, 1000 and 2000 ng/mL, respectively. The recoveries of paeonol from rat plasma were found to be 101.9, 104.5, 105.4 and 101.2% for concentrations of 50, 500, 1000 and 2000 ng/mL, respectively. The paeonol plasma concentrations were ﬁtted to two‐compartment model with ﬁrst order absorption. The mean terminal half‐lives (t1/2) of paeonol was 80.9 min. Copyright © 2003 John Wiley & Sons, Ltd.
HPLC determination of ferulic acid in rat plasma after oral administration of Rhizoma Chuanxiong and its compound preparation
Authors: Li Yujuan , Bi Kaishun 
Published: December 2003

AbstractAn HPLC method is described for determination of ferulic acid in rat plasma. The concentration of ferulic acid in rat plasma was determined after deproteinization with acetonitrile using sulfamethoxazole as internal standard. Chromatographic separations were performed on a C18 stationary phase with a mobile phase composed of acetonitrile–water (16:84, v/v) with 1% glacial acetic acid. The UV detection wavelength was set at 320 nm. The method was successfully applied to the determination of pharmacokinetic parameters in rat plasma after oral administration of Rhizoma Chuanxiong and and its compound preparation Suanzaoren decoctions. The calibration curve was linear over the range 0.0510–4.08 µg/mL in rat plasma. Within‐day and between‐day precisions were less than 4.5% RSD. Mean recovery was determined as 96.9%. The limit of quantitation was 0.0510 µg/mL. The pharmacokinetic parameters of the two preparations were different signiﬁcantly (p < 0.05), which may attribute to the effects of other ingredients present in Suanzaoren decoction. Copyright © 2003 John Wiley & Sons, Ltd.