bluuebunny/crossref_metadata_2025 huggingface dataset:
Higas in rejuvenated radio galaxies: Giant Metrewave Radio Telescope observations of the DDRG J1247+6723
Authors: Saikia D. J. , Gupta Neeraj , Konar C.
Published: January 2007

We report the detection of H i absorption towards the inner double of the double-double radio galaxy (DDRG) J1247+6723 with the Giant Metrewave Radio Telescope (GMRT). The inner double is a gigahertz peaked spectrum (GPS) source with a linear size of 14 pc while the overall size defined by the outer double is 1195 kpc, making it a giant radio source. The absorption profile is well resolved and consists of a number of components on either side of the optical systemic velocity. The neutral hydrogen column density is estimated to be N(H i) = 6.73 × 1020 (Ts/100)(1.0/fc) cm−2, where Ts and fc are the spin temperature and partial coverage of the background source, respectively. We explore any correlation between the occurrence of H i absorption and rejuvenation of radio activity and suggest that there could be a strong relationship between them.
Ability of Monocyte-Derived Dendritic Cells To Secrete Oxygen Radicals in Response to Formyl Peptide Receptor Family Agonists Compared to That of Myeloid and Plasmacytoid Dendritic Cells
Authors: Karlsson Anna , Nygren Erik , Karlsson Jennie , Nordström Inger , Dahlgren Claes , Eriksson Kristina
Published: January 2007

We show that human monocyte-derived dendritic cells (DC) differ considerably from freshly isolated blood-derived myeloid and plasmacytoid DC in their abilities to produce reactive oxygen species in response to different agonists to the formyl peptide receptor family and are thus poor representatives of blood DC in this field of research.
DNA Vaccine Construct Incorporating Intercellular Trafficking and Intracellular Targeting Motifs Effectively Primes and Induces Memory B- and T-Cell Responses in Outbred Animals
Authors: Mwangi Waithaka , Brown Wendy C. , Splitter Gary A. , Davies Christopher J. , Howard Chris J. , Hope Jayne C. , Aida Yoko , Zhuang Yan , Hunter Beverly J. , Palmer Guy H.
Published: January 2007

We developed a vaccine construct in which a BVP22 domain and an invariant-chain major histocompatibility complex class II-targeting motif capable of enhancing dendritic cell antigen uptake and presentation were fused to a sequence encoding a B- and T-cell antigen from the
Anaplasma marginale
major surface protein 1a and tested whether this construct would prime and expand immune responses in outbred calves. A single inoculation with this construct effectively primed the immune responses, as demonstrated by a significant enhancement of CD4
+
T-cell proliferation compared to that in calves identically inoculated but inoculated with a DNA construct lacking the targeting domains and compared to that in calves inoculated with an empty vector. These proliferative responses were mirrored by priming and expansion of gamma interferon-positive CD4
+
T cells and immunoglobulin G responses against the linked B-cell epitope. Priming by the single immunization induced memory that underwent rapid recall following reexposure to the antigen. These results demonstrate that DNA vaccines targeting key intercellular and intracellular events significantly enhance priming and expansion and support the feasibility of single-dose DNA immunization in outbred populations.
Cost-Effective Real-Time Reverse Transcriptase PCR (RT-PCR) To Screen for Dengue Virus followed by Rapid Single-Tube Multiplex RT-PCR for Serotyping of the Virus
Authors: Lai Yee-Ling , Chung Youne-Kow , Tan Hwee-Cheng , Yap Hoon-Fang , Yap Grace , Ooi Eng-Eong , Ng Lee-Ching
Published: January 2007

Virus detection methodology provides detection of dengue virus in the early phase of the disease. PCR, targeting cDNA derived from viral RNA, has been used as a laboratory-based molecular tool for the detection of
Dengue virus
. We report the development and use of three real-time one-step reverse transcriptase PCR (RT-PCR) assays to detect dengue cases and serotype the virus involved. The first RT-PCR assay uses SYBR green I as the reporting dye for the purpose of cost-effective screening for dengue virus. The detection limit of the SYBR green I assay was 10 PFU/ml (0.01 equivalent PFU per assay) for all four dengue virus serotypes. The second RT-PCR assay is a duplex fluorogenic probe-based real-time RT-PCR for serotyping clinical samples for dengue viruses. The detection threshold of the probe-based RT-PCR format was 0.1 PFU for serotypes Dengue-1 and Dengue-2, 1 PFU for serotype Dengue-3, and 0.01 PFU for serotype Dengue-4. The third is a fourplex assay that detects any of the four serotypes in a single closed tube with comparable sensitivity. Validation of the assays with local clinical samples collected from 2004 to 2006 revealed that there was an 88% positive correlation between virus isolation and RT-PCR with regard to dengue virus detection and a 100% correlation with seroconversion in subsequent samples. The serotyping results derived from duplex and fourplex assays agree fully with each other and with that derived from immunofluorescence assays.
Multiplex Real-Time PCR Targeting the RNase P RNA Gene for Detection and Identification of
Candida
Species in Blood
Authors: Innings Åsa , Ullberg Måns , Johansson Anders , Rubin Carl Johan , Noreus Niklas , Isaksson Magnus , Herrmann Björn
Published: January 2007

We have developed a single-tube multiplex real-time PCR method for the detection of the eight most common
Candida
species causing septicemia:
Candida albicans
,
C. dubliniensis
,
C. famata
,
C. glabrata
,
C. guilliermondii
,
C. krusei
,
C. parapsilosis
, and
C. tropicalis
. The method developed targets the RNase P RNA gene
RPR1
. Sequences of this gene were determined for seven of the
Candida
species and showed surprisingly large sequence variation.
C. glabrata
was found to have a gene that was five times longer gene than those of the other species, and the nucleotide sequence similarity between
C. krusei
and
C. albicans
was as low as 55%. The multiplex PCR contained three probes that enabled the specific detection of
C. albicans
,
C. glabrata
, and
C. krusei
and a fourth probe that allowed the general detection of the remaining species. The method was able to detect 1 to 10 genome copies when the detection limit was tested repeatedly for the four species
C. albicans
,
C. glabrata
,
C. krusei
, and
C. guilliermondii
. No significant difference in the detection limit was seen when the multiplex format was compared with single-species PCR, i.e., two primers and one probe. The method detected eight clinically relevant
Candida
species and did not react with other tested non-
Candida
species or human DNA. The assay was applied to 20 blood samples from nine patients and showed a sensitivity similar to that of culture.
Multicenter Comparison of the VITEK 2 Yeast Susceptibility Test with the CLSI Broth Microdilution Reference Method for Testing Fluconazole against
Candida
spp
Authors: Pfaller M. A. , Diekema D. J. , Procop G. W. , Rinaldi M. G.
Published: January 2007

A fully automated commercial antifungal susceptibility test system (VITEK 2 yeast susceptibility test; bioMerieux, Inc., Hazelwood, Mo.) was compared in three different laboratories with Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) method by testing two quality control strains and a total of 426 isolates of
Candida
spp. (103 to 135 clinical isolates in each laboratory plus 80 challenge isolates in one laboratory) against fluconazole. Reference BMD MIC endpoints were established after 24 and 48 h of incubation. VITEK 2 endpoints were determined spectrophotometrically after 10 to 26 h of incubation (mean, 13 h). Excellent essential agreement (within two dilutions) between the VITEK 2 and the 24- and 48-h BMD MICs was observed. The overall agreement values were 97.9 and 93.7%, respectively. Both intra- and interlaboratory agreement was 100%. The overall categorical agreement between VITEK 2 and BMD was 97.2% at the 24-h BMD time point and 88.3% at the 48-h BMD time point. Decreased categorical agreement at 48 h was attributed to trailing growth observed with
Candida glabrata
. The VITEK 2 system reliably detected fluconazole resistance among
Candida
spp. and demonstrated excellent quantitative and qualitative agreement with the reference BMD method.
Binding Patterns of Human Norovirus-Like Particles to Buccal and Intestinal Tissues of Gnotobiotic Pigs in Relation to A/H Histo-Blood Group Antigen Expression
Authors: Cheetham S. , Souza M. , McGregor R. , Meulia T. , Wang Q. , Saif L. J.
Published: January 2007

Histo-blood group antigen (HBGA) phenotypes have been associated with susceptibility to human noroviruses (HuNoVs). Our aims were: (i) to determine the patterns of A/H HBGA expression in buccal and intestinal tissues of gnotobiotic (Gn) pigs; (ii) to determine if virus-like particles (VLPs) of HuNoV genogroup I (GI) and GII bind to A- or H-type tissues; (iii) to compare A/H expression and VLP binding patterns and confirm their binding specificities by blocking assays; (iv) to develop a hemagglutination inhibition test using buccal cells from live pigs to determine the Gn pig's A/H phenotype and to match viral strains with previously determined HuNoV VLP binding specificities; and (v) to determine the A/H phenotypes and compare these data to the infection outcomes of a previous study of 65 Gn pigs inoculated with HuNoV GII/4 strain HS66 and expressing A and/or H or neither antigen on their buccal and intestinal tissues (S. Cheetham, M. Souza, T. Meulia, S. Grimes, M. G. Han, and L. J. Saif, J. Virol. 80:10372-10381, 2006). We found that the HuNoV GI/GII VLPs of different clusters bound to tissues from four pigs tested (two A+and two H+). The GI/1 and GII/4 VLPs bound extensively to duodenal and buccal tissues from either A+or H+pigs, but surprisingly, GII/1 and GII/3 VLPs bound minimally to the duodenum of an A+pig. The VLP binding was partially inhibited by A-, H1-, or H2-specific monoclonal antibodies, but was completely blocked by porcine mucin. Comparing the A/H phenotypes of 65 HS66-inoculated Gn pigs from our previous study, we found that significantly more A+and H+pigs (51%) than non-A+and non-H+pigs (12.5%) shed virus. From the 22 convalescent pigs, significantly more A+or H+pigs (66%) than non-A+or H+pigs (25%) seroconverted.
Role of Interferon Regulatory Factor 3 in Type I Interferon Responses in Rotavirus-Infected Dendritic Cells and Fibroblasts
Authors: Douagi Iyadh , McInerney Gerald M. , Hidmark Åsa S. , Miriallis Vassoula , Johansen Kari , Svensson Lennart , Karlsson Hedestam Gunilla B.
Published: January 2007

The main pathway for the induction of type I interferons (IFN) by viruses is through the recognition of viral RNA by cytosolic receptors and the subsequent activation of interferon regulatory factor 3 (IRF-3), which drives IFN-α/β transcription. In addition to their role in inducing an antiviral state, type I IFN also play a role in modulating adaptive immune responses, in part via their effects on dendritic cells (DCs). Many viruses have evolved mechanisms to interfere with type I IFN induction, and one recently reported strategy for achieving this is by targeting IRF-3 for degradation, as shown for rotavirus nonstructural protein 1 (NSP1). It was therefore of interest to investigate whether rotavirus-exposed DCs would produce type I IFN and/or mature in response to the virus. Our results demonstrate that IRF-3 was rapidly degraded in rotavirus-infected mouse embryonic fibroblasts (MEFs) and type I IFN was not detected in these cultures. In contrast, rotavirus induced type I IFN production in myeloid DCs (mDCs), resulting in their activation. Type I IFN induction in response to rotavirus was reduced in mDCs from IRF-3−/−mice, indicating that IRF-3 was important for mediating the response. Exposure of mDCs to UV-treated rotavirus induced significantly higher type I IFN levels, suggesting that rotavirus-encoded functions also antagonized the response in DCs. However, in contrast to MEFs, this action was not sufficient to completely abrogate type I IFN induction, consistent with a role for DCs as sentinels for virus infection.
Construction of an Infectious Rhesus Rhadinovirus Bacterial Artificial Chromosome for the Analysis of Kaposi's Sarcoma-Associated Herpesvirus-Related Disease Development
Authors: Estep Ryan D. , Powers Michael F. , Yen Bonnie K. , Li He , Wong Scott W.
Published: January 2007

Rhesus rhadinovirus (RRV) is closely related to Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 (HHV-8) and causes KSHV-like diseases in immunocompromised rhesus macaques (RM) that resemble KSHV-associated diseases including multicentric Castleman's disease and non-Hodgkin's lymphoma. RRV retains a majority of open reading frames (ORFs) postulated to be involved in the pathogenesis of KSHV and is the closest available animal model to KSHV infection in humans. Here we describe the generation of a recombinant clone of RRV strain 17577 (RRV
17577
) utilizing bacterial artificial chromosome (BAC) technology. Characterization of the RRV BAC demonstrated that it is a pathogenic molecular clone of RRV
17577
, producing virus that behaves like wild-type RRV both in vitro and in vivo. Specifically, BAC-derived RRV displays wild-type growth properties in vitro and readily infects simian immunodeficiency virus-infected RM, inducing B cell hyperplasia, persistent lymphadenopathy, and persistent infection in these animals. This RRV BAC will allow for rapid genetic manipulation of the RRV genome, facilitating the creation of recombinant versions of RRV that harbor specific alterations and/or deletions of viral ORFs. This system will provide insights into the roles of specific RRV genes in various aspects of the viral life cycle and the RRV-associated pathogenesis in vivo in an RM model of infection. Furthermore, the generation of chimeric versions of RRV containing KSHV genes will allow analysis of the function and contributions of KSHV genes to viral pathogenesis by using a relevant primate model system.
Classical Swine Fever Virus NproInteracts with Interferon Regulatory Factor 3 and Induces Its Proteasomal Degradation
Authors: Bauhofer Oliver , Summerfield Artur , Sakoda Yoshihiro , Tratschin Jon-Duri , Hofmann Martin A. , Ruggli Nicolas
Published: January 2007

Viruses have evolved a multitude of strategies to subvert the innate immune system by interfering with components of the alpha/beta interferon (IFN-α/β) induction and signaling pathway. It is well established that the pestiviruses prevent IFN-α/β induction in their primary target cells, such as epitheloidal and endothelial cells, macrophages, and conventional dendritic cells, a phenotype mediated by the viral protein Npro. Central players in the IFN-α/β induction cascade are interferon regulatory factor 3 (IRF3) and IRF7. Recently, it was proposed that classical swine fever virus (CSFV), the porcine pestivirus, induced the loss of IRF3 by inhibiting the transcription of IRF3 mRNA. In the present study, we show that endogenous IRF3 and IRF3 expressed from a cytomegalovirus (CMV) promoter are depleted in the presence of CSFV by means of Npro, while CSFV does not inhibit CMV promoter-driven protein expression. We also demonstrate that CSFV does not reduce the transcriptional activity of the IRF3 promoter and does not affect the stability of IRF3 mRNA. In fact, CSFV Nproinduces proteasomal degradation of IRF3, as demonstrated by proteasome inhibition studies. Furthermore, Nprocoprecipitates with IRF3, suggesting that the proteasomal degradation of IRF3 is induced by a direct or indirect interaction with Npro. Finally, we show that Nprodoes not downregulate IRF7 expression.
The Infected Cell Protein 0 Encoded by Bovine Herpesvirus 1 (bICP0) Induces Degradation of Interferon Response Factor 3 and, Consequently, Inhibits Beta Interferon Promoter Activity
Authors: Saira Kazima , Zhou You , Jones Clinton
Published: January 2007

The ICP0 protein (bICP0) encoded by bovine herpesvirus 1 is the major viral regulatory protein because it stimulates all viral promoters and, consequently, productive infection. Like other ICP0 analogues encoded by
Alphaherpesvirinae
subfamily members, bICP0 contains a zinc RING finger near its amino terminus that is necessary for activating transcription, regulating subcellular localization, and inhibiting interferon-dependent transcription. In this study, we discovered that sequences near the C terminus, and the zinc RING finger, are necessary for inhibiting the human beta interferon (IFN-β) promoter. In contrast to herpes simplex virus type 1-encoded ICP0, bICP0 reduces interferon response factor 3 (IRF3), but not IRF7, protein levels in transiently transfected cells. The zinc RING finger and sequences near the C terminus are necessary for bICP0-induced degradation of IRF3. A proteasome inhibitor, lactacystin, interfered with bICP0-induced degradation of IRF3, suggesting that bICP0, directly or indirectly, targets IRF3 for proteasome-dependent degradation. IRF3, but not IRF7, is not readily detectable in the nuclei of productively infected bovine cells during the late stages of infection. In the context of productive infection, IRF3 and IRF7 are detected in the nucleus at early times after infection. At late times after infection, IRF7, but not IRF3, is still detectable in the nuclei of infected cells. Collectively, these studies suggest that the ability of bICP0 to reduce IRF3 protein levels is important with respect to disarming the IFN response during productive infection.
AMPK-Mediated Inhibition of mTOR Kinase Is Circumvented during Immediate-Early Times of Human Cytomegalovirus Infection
Authors: Kudchodkar Sagar B. , Del Prete Gregory Q. , Maguire Tobi G. , Alwine James C.
Published: January 2007

Human cytomegalovirus (HCMV) infection increases synthetic rates in infected cells. The resulting increase in energy utilization could potentially increase the AMP:ATP ratio, causing activation of 5′-AMP-activated protein kinase (AMPK). Activated AMPK promotes inhibition of mammalian target of rapamycin (mTOR) kinase, which could be deleterious to the viral infection. Using the AMPK-activating drug 5-amino-4-imidazolecarboxamide ribose (AICAR), we showed that, by 12 h post-HCMV infection, inhibition of mTOR by AMPK is circumvented. However, growth curves showed that progeny virion production is inhibited when AICAR is added, suggesting other inhibitory effects of AICAR or activated AMPK.
Direct Visualization of the Putative Portal in the Kaposi's Sarcoma-Associated Herpesvirus Capsid by Cryoelectron Tomography
Authors: Deng Binbin , O'Connor Christine M. , Kedes Dean H. , Zhou Z. Hong
Published: January 2007

Genetic and biochemical studies have suggested the existence of a bacteriophage-like, DNA-packaging/ejecting portal complex in herpesviruses capsids, but its arrangement remained unknown. Here, we report the first visualization of a unique vertex in the Kaposi's sarcoma-associated herpesvirus (KSHV) capsid by cryoelectron tomography, thus providing direct structural evidence for the existence of a portal complex in a gammaherpesvirus. This putative KSHV portal is an internally localized, umbilicated structure and lacks all of the external machineries characteristic of portals in DNA bacteriophages.
Scavenger Receptor BI and BII Expression Levels Modulate Hepatitis C Virus Infectivity
Authors: Grove Joe , Huby Thierry , Stamataki Zania , Vanwolleghem Thomas , Meuleman Philip , Farquhar Michelle , Schwarz Anne , Moreau Martine , Owen James S. , Leroux-Roels Geert , Balfe Peter , McKeating Jane A.
Published: January 2007

Hepatitis C virus (HCV) enters cells via a pH- and clathrin-dependent endocytic pathway. Scavenger receptor BI (SR-BI) and CD81 are important entry factors for HCV internalization into target cells. The SR-BI gene gives rise to at least two mRNA splice variants, SR-BI and SR-BII, which differ in their C termini. SR-BI internalization remains poorly understood, but SR-BII is reported to endocytose via a clathrin-dependent pathway, making it an attractive target for HCV internalization. We demonstrate that HCV soluble E2 can interact with human SR-BI and SR-BII. Increased expression of SR-BI and SR-BII in the Huh-7.5 hepatoma cell line enhanced HCV strain J6/JFH and JFH infectivity, suggesting that endogenous levels of these receptors limit infection. Elevated expression of SR-BI, but not SR-BII, increased the rate of J6/JFH infection, which may reflect altered intracellular trafficking of the splice variants. In human plasma, HCV particles have been reported to be complexed with lipoproteins, suggesting an indirect interaction of the virus with SR-BI and other lipoprotein receptors. Plasma from J6/JFH-infected uPA-SCID mice transplanted with human hepatocytes demonstrates an increased infectivity for SR-BI/II-overexpressing Huh-7.5 cells. Plasma-derived J6/JFH infectivity was inhibited by an anti-E2 monoclonal antibody, suggesting that plasma virus interaction with SR-BI was glycoprotein dependent. Finally, anti-SR-BI antibodies inhibited the infectivity of cell culture- and plasma-derived J6/JFH, suggesting a critical role for SR-BI/II in HCV infection.
Bovine Viral Diarrhea Virus: Prevention of Persistent Fetal Infection by a Combination of Two Mutations Affecting ErnsRNase and NproProtease
Authors: Meyers Gregor , Ege Andreas , Fetzer Christiane , von Freyburg Martina , Elbers Knut , Carr Veronica , Prentice Helen , Charleston Bryan , Schürmann Eva-Maria
Published: January 2007

Different genetically engineered mutants of bovine viral diarrhea virus (BVDV) were analyzed for the ability to establish infection in the fetuses of pregnant heifers. The virus mutants exhibited either a deletion of the overwhelming part of the genomic region coding for the N-terminal protease Npro, a deletion of codon 349, which abrogates the RNase activity of the structural glycoprotein Erns, or a combination of both mutations. Two months after infection of pregnant cattle with wild-type virus or either of the single mutants, the majority of the fetuses contained virus or were aborted or found dead in the uterus. In contrast, the double mutant was not recovered from fetal tissues after a similar challenge, and no dead fetuses were found. This result was verified with a nonrelated BVDV containing similar mutations. After intrauterine challenge with wild-type virus, mutated viruses, and cytopathogenic BVDV, all viruses could be detected in fetal tissue after 5, 7, and 14 days. Type 1 interferon (IFN) could be detected in fetal serum after challenge, except with wild-type noncytopathogenic BVDV. On days 7 and 14 after challenge, the largest quantities of IFN in fetal serum were induced by the Nproand RNase-negative double mutant virus. The longer duration of fetal infection with the double mutant resulted in abortion. Therefore, for the first time, we have demonstrated the essential role of both Nproand ErnsRNase in blocking interferon induction and establishing persistent infection by a pestivirus in the natural host.
The influence of fine aggregate combinations on particle size distribution, grading parameters, and compressive strength of sandcrete blocks
Authors: Omoregie A , Alutu O E
Published: January 2007

The current extensive use of low priced fine aggregate (sand) deposits in sandcrete block making in Nigeria is of concern because there appears to be a level of ignorance surrounding their existing properties and implications. To this end, silt contents and some grading parameters of the most commonly used fine aggregate deposits in parts of midwestern Nigeria (Benin City), the coefficient of uniformity (Cu), curvature coefficient (Cc), and the fineness modulus (Fm) were derived by laboratory experiments to ascertain these basic properties. In addition, the strength and durability properties of sandcrete blocks made from these sands were also established. It revealed that the low priced sands exhibited worse properties in comparison to the more expensive sand. As a way of improving the properties of these frequently used low priced sands, a combination approach was adopted that used the weaker and commonly used sands with those that are more expensive and less frequently used. Findings revealed that combining the two created significant improvement in compressive strength, durability, and grading parameters of low priced sands with only marginal impact on cost.Key words: fine aggregates, uniformity coefficient, curvature coefficient, fineness modulus, compressive strength, durability, silt contents, Nigeria.
Damage assessment of steel angle members subjected to very-low-cycle loading
Authors: Park Yeon-Soo , Park Sun-Joon , Kang Sung-Hoo , Suh Byung-Chul
Published: January 2007

This study deals with damage processes to steel structural members up to an ultimate cracking state caused by local buckling that occurs under large deformations due to very-low-cycle loading. In this study, a very-low-cycle loading means a repetitive loading, with 5 to 20 loading cycles, within the large plastic range. Experiments were conducted on steel angle members that were subjected to very-low-cycle loading that caused global and (or) local buckling and plastic elongation. The objective of the experiments was to quantify important physical factor relationships between cracks and ruptures to large repetitive deformations. A nonlinear finite element method analysis was performed to trace the experimental behavior of steel structural members. A new approach to seismic damage assessment for steel members is proposed based on local stress-strain histories and cumulative states of deformation at critical parts.Key words: damage index, very-low-cycle loading, local strain, buckling, crack, steel member.
Analytical procedures for evaluating factors that affect joint faulting for jointed plain concrete pavements using the Long-Term Pavement Performance database
Authors: Jung Jong-Suk , Owusu-Antwi Emmanuel B , An Ji-Hwan
Published: January 2007

The objective of this study was to identify and quantify design and construction features most important to joint faulting of joint plain concrete pavements. With data obtained from the Long-Term Pavement Performance (LTPP) database, an analysis approach that combined pavement engineering expertise and modern data analysis techniques was to develop guidelines for improved design and construction of Portland cement concrete (PCC) pavement. The approach included typical preliminary analyses, but emphasis was placed on using a series of multivariate data analysis techniques. Discriminant analysis was used to develop models that classify individual pavement into performance groups developed by cluster analysis, which was used to partition the pavements into three distinct groups representing good, normal, and poor performance. These models can be used to classify and evaluate additional or new pavements performance throughout the pavement's design life. To quantify the levels of the key design and construction features that contribute to performance, the classification and regression tree procedure was used to develop tree-based models for performance measure. The analysis approach described was used to develop the guideline on the key design and construction features that can be used by designers to decrease joint faulting of jointed plain concrete pavements (JPCPs).Key words: faulting, Long-Term Pavement Performance (LTPP), jointed plain concrete pavement (JPCP), cluster analysis, discriminant analysis, classification and regression tree (CART) analysis.
Evaluation of the effects of spectrum-compatible seismic excitations on the response of medium-height reinforced concrete frame buildings
Authors: Naumoski Nove , Saatcioglu Murat , Lin Lan , Amiri-Hormozaki Kambiz
Published: January 2007

Spectrum-compatible seismic excitations are required when dynamic time-history analysis is used for determining the response of a structure. This paper presents results from a study on the effects of different types of spectrum-compatible excitations on the response of medium-height reinforced concrete frame buildings. Two six-storey buildings designed for Vancouver and a five-storey building designed for Montréal were used in the study. Nonlinear time-history analyses were conducted by subjecting the buildings to selected ensembles of spectrum-compatible excitations (i.e., accelerograms). The ensembles used in the study included spectrum-compatible artificial accelerograms, simulated stochastic accelerograms, and recorded earthquake accelerograms (i.e., real accelerograms) scaled to the design spectrum ordinate at the fundamental building period and to the area under the design spectrum within the predominant period range of the building. The responses of the buildings resulting from spectrum-compatible artificial accelerograms and those from scaled real accelerograms were found to be quite similar. Based on the results of this study, the scaling of real accelerograms to spectral area is preferred for obtaining spectrum-compatible accelerograms.Key words: seismic, excitation, response, spectrum, accelerogram, building, drift, curvature, ductility.
Angiotensin-(1–7) potentiates responses to bradykinin but does not change responses to angiotensin I
Authors: Greco A. Joel , Master Ryan G. , Fokin Alex , Baber Syed R. , Kadowitz Philip J.
Published: January 2007

Angiotensin-(1–7) (Ang-(1–7)), a bioactive peptide in the renin–angiotensin system, has counterregulatory actions to angiotensin II (Ang II). However, the mechanism by which Ang-(1–7) enhances vasodepressor responses to bradykinin (BK) is not well understood. In the present study, the effects of Ang-(1–7) on responses to BK, BK analogs, angiotensin I (Ang I), and Ang II were investigated in the anesthetized rat. The infusion of Ang-(1–7) (55 pmol/min i.v.) enhanced decreases in systemic arterial pressure in response to i.v. injections of BK and the BK analogs [Hyp3, Tyr(Me)8]-bradykinin (HT-BK) and [Phe8ψ (CH2-NH) Arg9]-bradykinin (PA-BK) without altering pressor responses to Ang I or II, or depressor responses to acetylcholine and sodium nitroprusside. The angiotensin-converting enzyme (ACE) inhibitor enalaprilat enhanced responses to BK and the BK analog HT-BK without altering responses to PA-BK and inhibited responses to Ang I. The potentiating effects of Ang-(1–7) and enalaprilat on responses to BK were not attenuated by the Ang-(1–7) receptor antagonist A-779. Ang-(1–7)- and ACE inhibitor-potentiated responses to BK were attenuated by the BK B2 receptor antagonist Hoe 140. The cyclooxygenase inhibitor sodium meclofenamate had no significant effect on responses to BK or Ang-(1–7)-potentiated BK responses. These results suggest that Ang-(1–7) potentiates responses to BK by a selective B2 receptor mechanism that is independent of an effect on Ang-(1–7) receptors, ACE, or cyclooxygenase product formation. These data suggest that ACE inhibitor-potentiated responses to BK are not mediated by an A-779-sensitive mechanism and are consistent with the hypothesis that enalaprilat-induced BK potentiation is due to decreased BK inactivation.
Calcium-independent tacrine-induced relaxation of rat gastric corpus smooth muscles
Authors: Krustev Atanas D. , Argirova Mariana D. , Getova Damianka P. , Turiiski Valentin I. , Prissadova Natalia A.
Published: January 2007

Tacrine, a non-competitive reversible acetylcholinesterase and butyrylcholineserase inhibitor, caused a concentration-dependent tonic contraction of gastric smooth muscle preparations in the concentration range 1 × 10−7mol/L – 1 × 10−5mol/L, whereas concentrations higher than 2 × 10−5mol/L induced a biphasic effect; a short-time contraction was followed by a prolonged relaxation. To shed some light on the mechanism underlying this untypical relaxation, the amplitude of mechanical reactions caused by tacrine were compared with those of tacrine in the presence of atropine, ipratropium, metrifonate, TTX, nifedipine, D-600, caffeine, apamin, and charybdotoxin. The results obtained revealed that the relaxation was neither cholinergic in nature, nor mediated by the influence of the drug on intramural neuronal structures. It was not influenced by processes inducing changes in cytosolic Ca2+levels. This assumption was confirmed by experiments with permeabilized muscle preparations that were pre-contracted in a solution with pCa 5.5. Tacrine relaxed the smooth muscles in spite of the constant intracellular Ca2+concentration resulting from the permeabilization. These findings argue that tacrine at concentrations higher than 2 × 10−5mol/L has a desensitizing effect on the contractile apparatus of gastric corpus smooth muscle preparations towards Ca2+.
Chronic estrogen treatment reduces vaso-constrictor responses in insulin resistant rats
Authors: Song Dongzhe , Yuen Violet G. , Yao Linfu , McNeill John H.
Published: January 2007

Previous experiments have shown that chronic estrogen treatment via subcutaneous implants prevented insulin-induced blood pressure elevation and increased insulin sensitivity in ovariectomized female rats. In vitro vascular studies were performed using isolated mesenteric arteries to determine the effect of chronic estrogen and insulin treatments on vascular responses to vasoconstrictor agents. Female Wistar rats were assigned to the following groups: sham-operated, sham-operated plus insulin, sham-operated plus insulin plus estrogen, ovariectomized, ovariectomized plus insulin, and ovariectomized plus insulin plus estrogen. Chronic insulin and estrogen treatments were initiated with subcutaneous placement of insulin implants (2 U/d) and 17β-estradiol implants (0.5 mg/pellet, 60 day release) at the back of the neck. After 8 weeks of treatment, mesenteric arteries were isolated for assessment of constrictor responses to norepinephrine and the thromboxane A2 analogue U46619 in the presence or absence of the endothelium. The results show that chronic estrogen treatment attenuated the vascular constrictor responses to norepinephrine and U46619 only in endothelium intact vessels. Incubation with insulin did not significantly affect norepinephrine-induced vascular smooth muscle contraction. The study provides evidence that the mechanism by which estrogen prevents insulin-induced blood pressure elevation in insulin-treated ovariectomized rats is by influencing endothelium-derived vasoactive factors such as thromboxane A2.
Malonyl CoA control of fatty acid oxidation in the newborn heart in response to increased fatty acid supply
Authors: Onay-Besikci Arzu , Sambandam Nandakumar
Published: January 2007

The concentration of fatty acids in the blood or perfusate is a major determinant of the extent of myocardial fatty acid oxidation. Increasing fatty acid supply in adult rat increases myocardial fatty acid oxidation. Plasma levels of fatty acids increase post-surgery in infants undergoing cardiac bypass operation to correct congenital heart defects. How a newborn heart responds to increased fatty acid supply remains to be determined. In this study, we examined whether the tissue levels of malonyl CoA decrease to relieve the inhibition on carnitine palmitoyltransferase (CPT) I when the myocardium is exposed to higher concentrations of long-chain fatty acids in newborn rabbit heart. We then tested the contribution of the enzymes that regulate tissue levels of malonyl CoA, acetyl CoA carboxylase (ACC), and malonyl CoA decarboxylase (MCD). Our results showed that increasing fatty acid supply from 0.4 mmol/L (physiological) to 1.2 mmol/L (pathological) resulted in an increase in cardiac fatty acid oxidation rates and this was accompanied by a decrease in tissue malonyl CoA levels. The decrease in malonyl CoA was not related to any alterations in total and phosphorylated acetyl CoA carboxylase protein or the activities of acetyl CoA carboxylase and malonyl CoA decarboxylase. Our results suggest that the regulatory role of malonyl CoA remained when the hearts were exposed to high levels of fatty acids.
Inhibition of nonexocytotic norepinephrine release by desipramine reduces myocardial infarction size
Authors: Richardt Doreen , Dendorfer Andreas , Tölg Ralph , Dominiak Peter , Richardt Gert
Published: January 2007

During myocardial ischemia, a substantial accumulation of norepinephrine occurs in the ischemic zone due to a local nonexocytotic release of norepinephrine. Norepinephrine release is driven by the neuronal monoamine transporter (NET), which reverses its usual transmembrane transport direction. We investigated whether this local accumulation of norepinephrine contributes to irreversible myocardial injury in an in vivo model of myocardial infarction. Male, anaesthetized Wistar rats were subjected to 30 min coronary occlusion and subsequent 120 min reperfusion. Five minutes prior to coronary occlusion, the NET inhibitor desipramine was administered intravenously. Infarct size (IS) was determined by TTC-staining and was related to the area at risk (AAR). The influence of desipramine on cardiac norepinephrine release was investigated in isolated perfused hearts with 30 min of regional ischemia. Norepinephrine was measured in the effluent from the hearts by HPLC and electrochemical detection. Desipramine (0.1–0.8 mg/kg) dose-dependently reduced infarct size (IS/AAR) from 0.54 to 0.21 and suppressed postischemic norepinephrine release from 245 to 108 pg/mL. In summary, the data indicate that nonexocytotic release of norepinephrine in myocardial ischemia exaggerates acute ischemic damage, because suppression of ischemia-induced release of norepinephrine by the tricyclic antidepressant desipramine effectively reduces infarct size in an in vivo model of myocardial ischemia.
Thermodynamic stoichiometry of Na+-coupled glutathione transport
Authors: Gukasyan Hovhannes J. , Lee Vincent H.L. , Simityan Hagop , Kim Kwang-Jin , Kannan Ram
Published: January 2007

Ambiguity exists with respect to mechanisms of glutathione (GSH) transport and the molecular identity of GSH transporters. Empirical and theoretical limitations have hindered functional and molecular characterizations. Published literature referring to the isolation and molecular identification of Na+-coupled GSH transporters that mediate the cellular uptake of GSH is highly debated. Whereas a number of functional and kinetic reports of this putative symport mechanism exist, the hypothetical transmembrane Na+-coupled GSH transporter protein or the genetic message encoding it has not been isolated. Theoretical thermodynamic calculations to support the concept of secondary active GSH transport and to rationalize accounts of physical-kinetic measurements describing Na+-coupled cellular GSH uptake were performed. The adequacy of requisite energy and stoichiometric conservation of the separate electrical and chemical components of a Na+gradient in maintaining a high cellular accumulation gradient for GSH was examined through a purely phenomenological perspective. Dependent on the biological context, the energetic coupling between Na+and GSH cotransport may occur at ratios from 1:1 to 3:1. Molecular identification of specific transporters responsible for cellular Na+-coupled GSH uptake will facilitate determination of their relative contribution to the overall plasma membrane resting potential. In tissues with a high GSH concentration relative to their extracellular millieu, particularly in pathologies of cystic fibrosis and dry eye syndromes, large energy coupling ratios in cotransport of Na+and GSH may be expected. Na+-coupled GSH transport may play an important role in disease onset and (or) progression, or treatment modalities thereof.
Morphological and biochemical alterations in the jejunum following iodoacetamide-induced colitis in rats
Authors: Jurjus Abdo , Barada Kassem , Khoury Naim , Assef Mona Diab , Foltzer Charlotte Jourdainne , Reimund Jean Marie , Kedinger Michele
Published: January 2007

This study aims to describe the morphological alterations in the small and large intestines as well as the expression of some enterocyte enzymes and carriers in a rat model of iodoacetamide-induced colitis. Biopsies from the large and small intestines were taken at 1, 2, 4, 8, and 16 days postinduction and studied by light microscopy. The expressions of lactase, sucrase, aminopeptidase, and Glut-5 in the jejunum were studied by immunohistochemistry. Gene expressions of enterocyte lactase and sucrase were determined by RT-PCR using specific oligonucleotides. Microscopic examination of the large intestines revealed manifestations concordant with inflammation. Such alterations peaked at 2 days, were maintained to a lesser extent for 4 days, regressed by 8 days, and healed by 16 days. In the jejunum, the expression of lactase, sucrase, and aminopeptidase decreased 2 days after colitis induction, and recovered 2 days later. Similarly, Glut-5 expression decreased transiently with partial recovery by day 8. Compared with sham, gene expression of jejunal brush border enzymes sucrase and lactase showed a 4-fold increase in lactase and a 9-fold increase in sucrase after 4 days. We conclude that colitis can induce significant functional abnormalities in distant noninflamed small bowel regions.
The rapid onset of hyperglycaemia in ZDF rats was associated with a widespread alteration of metabolic proteins implicated in glucose metabolism in the heart
Authors: Lajoie Claude , Béliveau Louise , Trudeau François , Lavoie Nathalie , Massicotte Guy , Gagnon Sylvain , Calderone Angelino
Published: January 2007

The present study tested the hypothesis that the phosphorylation and regulation of metabolic proteins implicated in glucose homeostasis were impaired in the heart of the type 2 diabetic Zucker-diabetic-fatty (ZDF) rat model. The onset of hyperglycaemia in ZDF rats was not uniform, instead it either progressed rapidly (3–4 weeks) or was delayed (6–8 weeks). In both the early and late onset hyperglycaemic ZDF rats, AMPKα Thr172phosphorylation in the heart was significantly decreased. In the early onset hyperglycaemic ZDF rats, PKB Ser473phosphorylation was reduced, whereas Thr308phosphorylation was significantly increased. In the late onset hyperglycaemic ZDF rats, PKB Ser473phosphorylation was unchanged, but Thr308phosphorylation remained elevated. Cardiac GLUT4 protein and mRNA expression were significantly reduced in the early onset hyperglycaemic ZDF rats, whereas increased protein expression was observed in the late onset hyperglycaemic ZDF rats. In conclusion, the present study has demonstrated that following a more rapid onset of hyperglycaemia, the type 2 diabetic heart is more prone to alterations in the signaling proteins implicated in glucose metabolism.
ENERGY NORM A POSTERIORI ERROR ESTIMATION OF hp-ADAPTIVE DISCONTINUOUS GALERKIN METHODS FOR ELLIPTIC PROBLEMS
Authors: HOUSTON PAUL , SCHÖTZAU DOMINIK , WIHLER THOMAS P.
Published: January 2007

In this paper, we develop the a posteriori error estimation of hp-version interior penalty discontinuous Galerkin discretizations of elliptic boundary-value problems. Computable upper and lower bounds on the error measured in terms of a natural (mesh-dependent) energy norm are derived. The bounds are explicit in the local mesh sizes and approximation orders. A series of numerical experiments illustrate the performance of the proposed estimators within an automatic hp-adaptive refinement procedure.
EXISTENCE AND UNIQUENESS RESULTS FOR A CLASS OF RATE-INDEPENDENT HYSTERESIS PROBLEMS
Authors: MIELKE ALEXANDER , ROSSI RICCARDA
Published: January 2007

In this paper, we address the problem of existence, approximation, and uniqueness of solutions to an abstract doubly nonlinear equation, modeling a rate-independent process with hysteretic behavior. Models of this kind arise in, e.g., plasticity, solid phase transformations, and several other problems in non smooth mechanics. Existence of solutions is proved via passage to the limit in a time-discretization scheme, whereas uniqueness results are obtained by means of convex analysis techniques.
CONVERGENCE TO EQUILIBRIUM FOR A PARABOLIC–HYPERBOLIC PHASE-FIELD SYSTEM WITH NEUMANN BOUNDARY CONDITIONS
Authors: WU HAO , GRASSELLI MAURIZIO , ZHENG SONGMU
Published: January 2007

This paper is concerned with the asymptotic behavior of global solutions to a parabolic–hyperbolic coupled system which describes the evolution of the relative temperature θ and the order parameter χ in a material subject to phase transitions. For the system with homogeneous Neumann boundary conditions for both ¸ and χ, under the assumption that the nonlinearities λ and ϕ are real analytic functions, we prove the convergence of a global solution to an equilibrium as time goes to infinity by means of a suitable Łojasiewicz–Simon type inequality.
SPHERICAL AND NON-SPHERICAL GRAVITATIONAL COLLAPSE IN MONOPOLE-ANTI-DE SITTER–VAIDYA SPACE–TIME
Authors: PATIL K. D. , THOOL U. S.
Published: January 2007

In the present work, we investigate the influence of the monopole field on the occurrence of the space–time singularities in the gravitational collapse of anti-de Sitter–Vaidya space–time. It has been found that the spherically symmetric monopole-anti-de Sitter–Vaidya space–time contradicts the CCH, whereas the non-spherical collapse respects it.
GRAVITATIONAL WAVE SCINTILLATION BY A STELLAR CLUSTER
Authors: CONGEDO G. , DE PAOLIS F. , LONGO P. , NUCITA A. A. , VETRUGNO D. , QADIR ASGHAR
Published: January 2007

The diffraction effects on gravitational waves propagating through a stellar cluster are analyzed in the relevant approximation of Fresnel diffraction limit. We find that a gravitational wave scintillation effect — similar to the radio source scintillation effect — comes out naturally, implying that the gravitational wave intensity changes in a characteristic way as the observer moves.
DYNAMICS OF DARK ENERGY
Authors: COPELAND EDMUND J. , SAMI M. , TSUJIKAWA SHINJI
Published: January 2007

We review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating universe. In particular we discuss the arguments for and recent progress made towards understanding the nature of dark energy. We review the observational evidence for the current accelerated expansion of the universe and present a number of dark energy models in addition to the conventional cosmological constant, paying particular attention to scalar field models such as quintessence, K-essence, tachyon, phantom and dilatonic models. The importance of cosmological scaling solutions is emphasized when studying the dynamical system of scalar fields including coupled dark energy. We study the evolution of cosmological perturbations allowing us to confront them with the observation of the Cosmic Microwave Background and Large Scale Structure and demonstrate how it is possible in principle to reconstruct the equation of state of dark energy by also using Supernovae Ia observational data. We also discuss in detail the nature of tracking solutions in cosmology, particle physics and braneworld models of dark energy, the nature of possible future singularities, the effect of higher order curvature terms to avoid a Big Rip singularity, and approaches to modifying gravity which leads to a late-time accelerated expansion without recourse to a new form of dark energy.
PSEUDOSPIN SYMMETRY IN NUCLEI AS A RELATIVISTIC SYMMETRY
Authors: GINOCCHIO JOSEPH N.
Published: January 2007

We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We show that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment.