bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerisches Verfahren zur Optimierung von ebenen Stahlfachwerkträgern
Authors: Steiner Wolfgang , Eilbracht Gert 
Published: March 2006

AbstractDer vorliegende Aufsatz stellt ein numerisches Verfahren zur Gewichtsoptimierung von ebenen Stahlfachwerkträgern vor. Die Querschnittsabmessungen sowie die Fachwerkhöhe werden iterativ als freie Parameter bis zum Erreichen der gewichtsminimalen Fachwerkstruktur angepaßt. Die erzielten Informationen über Geometrie (Höhe) und Materialverbrauch, dargestellt in einem Höhen‐Gewichts‐Diagramm, sollen den Tragwerksplaner im Entwurfsprozeß bei der Auslegung von Fachwerkkonstruktionen unterstützen. Besonders im Hinblick auf ein ökologisches und ökonomisches Handeln gewinnt das gewichtsoptimierte Tragwerk im Entwurfsprozeß immer mehr an Bedeutung.
Auswirkungen von Temperatur, Schwinden und Kriechen auf Integralbrücken
Authors: Romeijn Arie 
Published: March 2006

AbstractEiner der wichtigsten Entwurfsparameter für Integralbrücken ist die waagerechte Verschiebung am Anschluß zwischen der Fahrbahnplatte und dem Widerlager. Integralbrücken gleichen Bewegungen des Oberbaus ohne konventionelle Dehnfugen oder Lager aus. Bei waagerechten Verschiebungen in Form von Dehnung oder Schrumpfung der Fahrbahnplatte handelt es sich also um einen der wesentlichen Unterschiede zwischen “klassischen” und integralen Brückenentwürfen.In diesem Aufsatz werden die Ergebnisse zu Untersuchungen bezüglich durch Temperatureinflüsse und Materialverhalten (zum Beispiel bei Vorspannung) verursachter waagerechter Verschiebungen einer Fahrbahnplatte aus Beton bei einer Gesamtbrückenlänge zwischen 20 m und 180 m vorgestellt. Dabei wurde auch der Einfluß unterschiedlicher Betonfestigkeitsklassen und Konstruktionsverfahren untersucht.
Transvaginal sonography in the morphological and functional assessment of segmental dilation of the distal ureter
Authors: Yang J.‐M. , Yang S.‐H. , Hsu H.‐C. , Huang W.‐C. 
Published: March 2006

AbstractPrimary megaureter presents a spectrum of findings ranging from mild, clinically unimportant, stable ureterectasis to severe, progressive obstructive hydroureteronephrosis. We report a patient with a double uterus and ipsilateral renal dystrophy. A previous imaging study had revealed a double uterus and obstructed left hemivagina, into which a single vaginal ectopic ureter inserted. On follow‐up intravenous urography 8 years later, the left kidney was non‐functioning, and there was segmental dilation of the distal right ureter. Transvaginal sonography with real‐time scanning and Doppler were useful in exploring the morphological and functional status of this dilated distal ureter. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Do early pregnancy ultrasound measurements correlate with fetal nuchal translucency at 11–14 weeks?
Authors: Prefumo F. , Condous G. , Papageorghiou A. , Thilaganathan B. , Bourne T. 
Published: March 2006

AbstractObjectiveTo assess whether extremes in nuchal translucency (NT) thickness measurements at 11–14 weeks of gestation are preceded by departures from normal in early ultrasound biometry or embryonic heart rate in euploid fetuses.MethodsThis was a retrospective analysis of data from women with singleton pregnancies examined in early pregnancy between June 2002 and January 2003, who subsequently had a nuchal translucency (NT) scan. The early pregnancy scan was performed transvaginally, and the crown–rump length (CRL), mean gestational sac diameter (GS), mean yolk sac diameter (YS) and embryonic heart rate (HR) were measured where possible. At the second scan CRL and NT were measured.ResultsA total of 534 singleton pregnancies were included in the analysis. The mean maternal age was 30 (range, 14–45) years, and 59.4% of the patients were nulliparous. The mean CRL was 11.5 (range, 1.4–30.0) mm at the first scan and 62.8 (range, 42.0–88.0) mm at the second scan. GS, YS and HR measurements were obtained in 87.6%, 72.5% and 72.5% of cases, respectively. No statistically significant correlation was observed between NT and Z‐scores of early pregnancy: GS (r = 0.013, P = 0.77), YS (r = 0.039, P = 0.44) or HR (r = 0.016, P = 0.76). GS, YS and HR were not significantly different in fetuses with NT measurements below the 10th percentile or above the 90th percentile (P = 0.24, 0.84 and 0.60, respectively).ConclusionUltrasound biometry and heart rate measured in early pregnancy are not related to nuchal translucency measurements at 11–14 weeks of gestation in chromosomally normal fetuses. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Blind adaptive modulation systems for wireless channels with binary feedback
Authors: Al‐Harthi Yahya , Tewfik Ahmed H. , Alouini Mohamed‐Slim 
Published: March 2006

AbstractIn this paper, we investigate the performance of a blind adaptive modulation scheme that does not require any channel knowledge and just uses binary feedback, thereby decreasing feedback load. Retransmission of erroneous packet is not considered. In particular, we present an analytical framework for the performance evaluation of a simple wireless system in terms of receiver and transmitter structure. The system requires no knowledge of the channel and relies on a binary feedback. Slow and fast Rayleigh fading channel conditions are considered. The paper includes the derivation of the closed‐form expressions of the spectral efficiency. In some cases, closed‐form expression for packet error rate (PER) are derived. Our results show relatively high PER but some applications can still operate in a satisfactory fashion in these conditions, such as voice communication. Using coded modulation with high coding gain and increasing the number of blocks per time slot decrease the PER even more. An advantage of this system is that it uses a low complexity receiver, which sends binary feedback. Copyright © 2006 John Wiley & Sons, Ltd.
Mobile location estimation for DS‐CDMA systems using self‐organizing maps
Authors: Xu Jun , Shen Xuemin (Sherman) , Mark Jon W. , Cai Jun 
Published: March 2006

AbstractIn this paper, a self‐organizing map (SOM) scheme for mobile location estimation in a direct‐sequence code division multiple access (DS‐CDMA) system is proposed. As a feedforward neural network with unsupervised or supervised and competitive learning algorithm, the proposed scheme generates a number of virtual neurons over the area covered by the corresponding base stations (BSs) and performs non‐linear mapping between the measured pilot signal strengths from nearby BSs and the user's location. After the training is finished, the location estimation procedure searches for the virtual sensor which has the minimum distance in the signal space with the estimated mobile user. Analytical results on accuracy and measurement reliability show that the proposed scheme has the advantages of robustness and scalability, and is easy for training and implementation. In addition, the scheme exhibits superior performance in the non‐line‐of‐sight (NLOS) situation. Numerical results under various terrestrial environments are presented to demonstrate the feasibility of the proposed SOM scheme. Copyright © 2006 John Wiley & Sons, Ltd.
A study on the PAPRs in multicarrier modulation systems with different orthogonal bases
Authors: Zhang Haixia , Yuan Dongfeng , Wang Cheng‐Xiang 
Published: March 2006

AbstractThis paper studies the peak‐to‐average power ratios (PAPRs) in multicarrier modulation (MCM) systems with seven different orthogonal bases, one Fourier base and six wavelet bases. It is shown by simulation results that the PAPRs of the Fourier‐based MCM system are lower than those of all wavelet‐based MCM (WMCM) systems. A novel threshold‐based PAPR reduction method is then proposed to reduce the PAPRs in WMCM systems. Both numerical and simulation results indicate that the proposed PAPR reduction method works very effectively in WMCM systems. Copyright © 2006 John Wiley & Sons, Ltd.
Investigation of multicast‐based mobility support in all‐IP cellular networks
Authors: Festag Andreas , Karl Holger , Wolisz Adam 
Published: March 2006

AbstractTo solve the IP mobility problem, the use of multicast has been proposed in a number of different approaches, applying multicast in different characteristic ways. We provide a systematic discussion of fundamental options for multicast‐based mobility support and the definition and experimental performance evaluation of selected schemes. The discussion is based on an analysis of the architectural, performance‐related, and functional requirements. By using these requirements and selecting options regarding network architecture and multicast protocols, we identify promising combinations and derive four case studies for multicast‐based mobility in IP‐based cellular networks. These case studies include both the standard any‐source IP multicast model as well as non‐standard multicast models, which optimally utilize the underlying multicast. We describe network architecture and protocols as well as a flexible software environment that allows to easily implement these and other classes of mobility‐supporting multicast protocols.Multicast schemes enable a high degree of flexibility for mobility mechanisms in order to meet the service quality required by the applications with minimal protocol overhead. We evaluate this overhead using our software environment by implementing prototypes and quantifying handoff‐specific metrics, namely, handoff and paging latency, packet loss and duplication rates, as well as TCP goodput. The measurement results show that these multicast‐based schemes improve handoff performance for high mobility in comparison to the reference cases: basic and hierarchical Mobile IP. Comparing the multicast‐schemes among each other the performance for the evaluated metrics is very similar.As a result of the conceptual framework classification and our performance evaluations, we justify specific protocol mechanisms that utilize specific features of the multicast. Based on this justification, we advocate the usage of a source‐specific multicast service model for multicast‐based mobility support that adverts the weaknesses of the classical Internet any‐source multicast service model. Copyright © 2006 John Wiley & Sons, Ltd.
Performance analysis of coded space‐time adaptive detection in DS/CDMA systems over Rayleigh fading channels
Authors: Hamouda Walaa , McLane Peter 
Published: March 2006

AbstractIn this paper, we study the use of channel coding in a direct‐sequence code‐division multiple‐access (DS‐CDMA) system that employs space‐time adaptive minimum‐mean square‐error (MMSE) interference suppression over Rayleigh fading channels. It is shown that the employment of adaptive antenna arrays at the receiver can assist in attenuating multiuser interference and at the same time speeds‐up the convergence rate of the adaptive receiver. In this work, we assess the accuracy of the theoretical results developed for the uncoded and convolutionally coded space‐time multiuser detector when applied to the adaptive case. It is found that the use of antenna arrays brings the receiver performance very close to its multiuser counterpart. Using performance error bounds, we show that a user‐capacity gain of approximately 200% can easily be achieved for the space‐time adaptive detector when used with a rate 1/2 convolutional code (CC) and a practical channel interleaver. This capacity gain is only 10% less than the gain achieved for the more complicated multiuser‐based receiver. Finally, we perform a comparison between convolutional and turbo coding where we find that the latter outperforms the former at all practical bit‐error rates (BER). Copyright © 2006 John Wiley & Sons, Ltd.
Thermostability enhancement and change in starch hydrolysis profile of the maltohexaose-forming amylase of Bacillus stearothermophilus US100 strain
Authors: Ben Ali Mamdouh , Khemakhem Bassem , Robert Xavier , Haser Richard , Bejar Samir 
Published: March 2006

The implications of Asn315 and Val450 in the atypical starch hydrolysis profile of Bacillus stearothermophilus Amy (α-amylase) US100 have been suggested previously [Ben Ali, Mhiri, Mezghani and Bejar (2001) Enzyme Microb. Tech. 28, 537–542]. In order to confirm this hypothesis, three mutants were generated. Of these two have a single mutation, N315D or V450G, whereas the third contains both mutations. Analysis of the starch breakdown-profile of these three mutants, as well as of the wild-type, allowed us to conclude that each single mutation induces a small variation in the hydrolysis product. However, the major end product produced by the double mutant shifts from maltopentaose/maltohexaose to maltose/maltotriose, confirming the involvement of these two residues in starch hydrolysis. The superimposition of AmyUS100 model with that of Bacillus licheniformis shows in AmyUS100 an additional loop containing residues Ile214 and Gly215. Remarkably, the deletion of these two residues increases the half-life at 100 °C from 15 min to approx. 70 min. Moreover, this engineered amylase requires less calcium, 25 p.p.m. instead of 100 p.p.m., to reach maximal thermostability.
Proteomic analysis of mouse kidney peroxisomes: identification of RP2p as a peroxisomal nudix hydrolase with acyl-CoA diphosphatase activity
Authors: Ofman Rob , Speijer Dave , Leen René , Wanders Ronald J. A. 
Published: March 2006

Proteomic analysis of mouse kidney peroxisomes resulted in the identification of a novel nudix hydrolase designated RP2p, which is encoded by the D7RP2e gene. RP2p consists of 357 amino acids and contains two conserved domains: a nudix hydrolase domain and a CoA-binding domain. In addition, a PTS (peroxisomal targeting signal) type 1 (Ala-His-Leu) was found at the C-terminus. Analysis of the enzyme characteristics revealed that RP2p is a CoA diphosphatase with activity towards CoA, oxidized CoA and a wide range of CoA esters, including choloyl-CoA and branched-chain fatty-acyl-CoA esters. The enzymatic properties of RP2p indicate that at low substrate concentrations medium and long-chain fatty-acyl-CoA esters are the primary substrates. Enzyme activity was optimal at pH 9 or above, and required the presence of Mg2+ or Mn2+ ions. Subcellular fractionation studies revealed that all CoA diphosphatase activity in mouse kidney is restricted to peroxisomes.
Comparing calpain- and caspase-3-mediated degradation patterns in traumatic brain injury by differential proteome analysis
Authors: Liu Ming Cheng , Akle Veronica , Zheng Wenrong , Dave Jitendra R. , Tortella Frank C. , Hayes Ronald L. , Wang Kevin K. W. 
Published: March 2006

A major theme of TBI (traumatic brain injury) pathology is the over-activation of multiple proteases. We have previously shown that calpain-1 and -2, and caspase-3 simultaneously produced αII-spectrin BDPs (breakdown products) following TBI. In the present study, we attempted to identify a comprehensive set of protease substrates (degradome) for calpains and caspase-3. We further hypothesized that the TBI differential proteome is likely to overlap significantly with the calpain- and caspase-3-degradomes. Using a novel HTPI (high throughput immunoblotting) approach and 1000 monoclonal antibodies (PowerBlot™), we compared rat hippocampal lysates from 4 treatment groups: (i) naïve, (ii) TBI (48 h after controlled cortical impact), (iii) in vitro calpain-2 digestion and (iv) in vitro caspase-3 digestion. In total, we identified 54 and 38 proteins that were vulnerable to calpain-2 and caspase-3 proteolysis respectively. In addition, the expression of 48 proteins was down-regulated following TBI, whereas that of only 9 was up-regulated. Among the proteins down-regulated in TBI, 42 of them overlapped with the calpain-2 and/or caspase-3 degradomes, suggesting that they might be proteolytic targets after TBI. We further confirmed several novel TBI-linked proteolytic substrates, including βII-spectrin, striatin, synaptotagmin-1, synaptojanin-1 and NSF (N-ethylmaleimide-sensitive fusion protein) by traditional immunoblotting. In summary, we demonstrated that HTPI is a novel and powerful method for studying proteolytic pathways in vivo and in vitro.
Characterization of retinaldehyde dehydrogenase 3
Authors: Graham Caroline E. , Brocklehurst Keith , Pickersgill Richard W. , Warren Martin J. 
Published: March 2006

RALDH3 (retinal dehydrogenase 3) was characterized by kinetic and binding studies, protein engineering, homology modelling, ligand docking and electrostatic-potential calculations. The major recognition determinant of an RALDH3 substrate was shown to be an eight-carbon chain bonded to the aldehyde group whose kinetic influence (kcat/Km at pH 8.5) decreases when shortened or lengthened. Surprisingly, the β-ionone ring of all-trans-retinal is not a major recognition site. The dissociation constants (Kd) of the complexes of RALDH3 with octanal, NAD+ and NADH were determined by intrinsic tryptophan fluorescence. The similarity of the Kd values for the complexes with NAD+ and with octanal suggests a random kinetic mechanism for RALDH3, in contrast with the ordered sequential mechanism often associated with aldehyde dehydrogenase enzymes. Inhibition of RALDH3 by tri-iodothyronine binding in competition with NAD+, predicted by the modelling, was established kinetically and by immunoprecipitation. Mechanistic implications of the kinetically influential ionizations with macroscopic pKa values of 5.0 and 7.5 revealed by the pH-dependence of kcat are discussed. Analogies with data for non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Streptococcus mutans, together with the present modelled structure of the thioacyl RALDH3, suggest (a) that kcat characterizes deacylation of this intermediate for specific substrates and (b) the assignment of the pKa of the major ionization (approximating to 7.5) to the perturbed carboxy group of Glu280 whose conjugate base is envisaged as supplying general base catalysis to attack of a water molecule. The macroscopic pKa of the minor ionization (5.0) is considered to approximate to that of the carboxy group of Glu488.
YZGD from Paenibacillus thiaminolyticus, a pyridoxal phosphatase of the HAD (haloacid dehalogenase) superfamily and a versatile member of the Nudix (nucleoside diphosphate x) hydrolase superfamily
Authors: Tirrell Isaac M. , Wall Jennifer L. , Daley Christopher J. , Denial Sarah J. , Tennis Frances G. , Galens Kevin G. , O'Handley Suzanne F. 
Published: March 2006

YZGD from Paenibacillus thiaminolyticus is a novel bifunctional enzyme with both PLPase (pyridoxal phosphatase) and Nudix (nucleoside diphosphate x) hydrolase activities. The PLPase activity is catalysed by the HAD (haloacid dehalogenase) superfamily motif of the enzyme, and the Nudix hydrolase activity is catalysed by the conserved Nudix signature sequence within a separate portion of the enzyme, as confirmed by site-directed mutagenesis. YZGD's phosphatase activity is very specific, with pyridoxal phosphate being the only natural substrate, while YZGD's Nudix activity is just the opposite, with YZGD being the most versatile Nudix hydrolase characterized to date. YZGD's Nudix substrates include the CDP-alcohols (CDP-ethanol, CDP-choline and CDP-glycerol), the ADP-coenzymes (NADH, NAD and FAD), ADP-sugars, TDP-glucose and, to a lesser extent, UDP- and GDP-sugars. Regardless of the Nudix substrate, one of the products is always a nucleoside monophosphate, suggesting a role in nucleotide salvage. Both the PLPase and Nudix hydrolase activities require a bivalent metal cation, but while PLPase activity is supported by Co2+, Mg2+, Zn2+ and Mn2+, the Nudix hydrolase activity is Mn2+-specific. YZGD's phosphatase activity is optimal at an acidic pH (pH 5), while YZGD's Nudix activities are optimal at an alkaline pH (pH 8.5). YZGD is the first enzyme reported to be a member of both the HAD and Nudix hydrolase superfamilies, the first PLPase to be recognized as a member of the HAD superfamily and the first Nudix hydrolase capable of hydrolysing ADP-x, CDP-x and TDP-x substrates with comparable substrate specificity.
Identification of a mitochondrial transporter for pyrimidine nucleotides in Saccharomyces cerevisiae: bacterial expression, reconstitution and functional characterization
Authors: Marobbio Carlo Marya Thomas , Di Noia Maria Antonietta , Palmieri Ferdinando 
Published: March 2006

Pyrimidine (deoxy)nucleoside triphosphates are required in mitochondria for the synthesis of DNA and the various types of RNA present in these organelles. In Saccharomyces cerevisiae, these nucleotides are synthesized outside the mitochondrial matrix and must therefore be transported across the permeability barrier of the mitochondrial inner membrane. However, no protein has ever been found to be associated with this transport activity. In the present study, Rim2p has been identified as a yeast mitochondrial pyrimidine nucleotide transporter. Rim2p (replication in mitochondria 2p) is a member of the mitochondrial carrier protein family having some special features. The RIM2 gene was overexpressed in bacteria. The purified protein was reconstituted into liposomes and its transport properties and kinetic parameters were characterized. It transported the pyrimidine (deoxy)nucleoside tri- and di-phosphates and, to a lesser extent, pyrimidine (deoxy)nucleoside monophosphates, by a counter-exchange mechanism. Transport was saturable, with an apparent Km of 207 μM for TTP, 404 μM for UTP and 435 μM for CTP. Rim2p was strongly inhibited by mercurials, bathophenanthroline, tannic acid and Bromocresol Purple, and partially inhibited by bongkrekic acid. Furthermore, the Rim2p-mediated heteroexchanges, TTP/TMP and TTP/TDP, are electroneutral and probably H+-compensated. The main physiological role of Rim2p is proposed to be to transport (deoxy)pyrimidine nucleoside triphosphates into mitochondria in exchange for intramitochondrially generated (deoxy)pyrimidine nucleoside monophosphates.
Herpes simplex virus type 1-encoded glycoprotein C contributes to direct coagulation Factor X–virus binding
Authors: Livingston Joel R. , Sutherland Michael R. , Friedman Harvey M. , Pryzdial Edward L. G. 
Published: March 2006

The HSV1 (herpes simplex virus type 1) surface has been shown recently to initiate blood coagulation by FVIIa (activated Factor VII)-dependent proteolytic activation of FX (Factor X). At least two types of direct FX–HSV1 interactions were suggested by observing that host cell-encoded tissue factor and virus-encoded gC (glycoprotein C) independently enhance FVIIa function on the virus. Using differential sedimentation to separate bound from free 125I-ligand, we report in the present study that, in the presence of Ca2+, FX binds directly to purified wild-type HSV1 with an apparent dissociation constant (Kd) of 1.5±0.4 μM and 206±24 sites per virus at saturation. The number of FX-binding sites on gC-deficient virus was reduced to 43±5, and the remaining binding had a lower Kd (0.7±0.2 μM), demonstrating an involvement of gC. Engineering gC back into the deficient strain or addition of a truncated soluble recombinant form of gC (sgC), increased the Kd and the number of binding sites. Consistent with a gC/FX stoichiometry of approximately 1:1, 121±6 125I-sgC molecules were found to bind per wild-type HSV1. In the absence of Ca2+, the number of FX-binding sites on the wild-type virus was similar to the gC-deficient strain in the presence of Ca2+. Furthermore, in the absence of Ca2+, direct sgC binding to HSV1 was insignificant, although sgC was observed to inhibit the FX–virus association, suggesting a Ca2+-independent solution-phase FX–sgC interaction. Cumulatively, these data demonstrate that gC constitutes one type of direct FX–HSV1 interaction, possibly providing a molecular basis for clinical correlations between recurrent infection and vascular pathology.