bluuebunny/crossref_metadata_2025 huggingface dataset:
Silica-Supported Erbium-based Nanosystems: An XPS Characterization
Authors: Armelao Lidia , Barreca Davide , Bottaro Gregorio , Gasparotto Alberto , Leonarduzzi Daniele , Maragno Cinzia , Tondello Eugenio
Published: April 2006

Silica-supported Er(III)-based nanocomposites were prepared by RF-sputtering from an Ar plasma. Depositions were carried out using an erbium target as a metal source and amorphous silica slides as growth surface. The substrate temperature was kept at 60 °C throughout each experiment. Attention was mainly devoted to the use of mild plasma conditions and to a proper choice of RF power, total pressure and deposition time in order to obtain a careful control of the deposited metal amount. Specimen characterization was performed by glancing-incidence x-ray diffraction (GIXRD), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) to investigate the structural, compositional and morphological properties of the obtained samples and their interrelations with the synthesis conditions. This study is dedicated to an XPS characterization of the principal core levels (Er, Si, O) of an Er(III)/SiO2 specimen obtained under selected conditions, leading to an incomplete silica coverage. This feature enabled investigation of the chemical state of both the deposited erbium-based particles and the supporting substrate. To this aim, detailed scans for the Er 4d, Si 2p, O ls, and C 1s regions and related data are presented and discussed.
Bacterial Sinusitis and Otitis Media following Influenza Virus Infection in Ferrets
Authors: Peltola Ville T. , Boyd Kelli L. , McAuley Julie L. , Rehg Jerold E. , McCullers Jonathan A.
Published: April 2006

Streptococcus pneumoniae
is the leading cause of otitis media, sinusitis, and pneumonia. Many of these infections result from antecedent influenza virus infections. In this study we sought to determine whether the frequency and character of secondary pneumococcal infections differed depending on the strain of influenza virus that preceded bacterial challenge. In young ferrets infected with influenza virus and then challenged with pneumococcus, influenza viruses of any subtype increased bacterial colonization of the nasopharynx. Nine out of 10 ferrets infected with H3N2 subtype influenza A viruses developed either sinusitis or otitis media, while only 1 out of 11 ferrets infected with either an H1N1 influenza A virus or an influenza B virus did so. These data may partially explain why bacterial complication rates are higher during seasons when H3N2 viruses predominate. This animal model will be useful for further study of the mechanisms that underlie viral-bacterial synergism.
Expression of
Haemophilus ducreyi
Collagen Binding Outer Membrane Protein NcaA Is Required for Virulence in Swine and Human Challenge Models of Chancroid
Authors: Fulcher Robert A. , Cole Leah E. , Janowicz Diane M. , Toffer Kristen L. , Fortney Kate R. , Katz Barry P. , Orndorff Paul E. , Spinola Stanley M. , Kawula Thomas H.
Published: April 2006

Haemophilus ducreyi
, the etiologic agent of the sexually transmitted genital ulcer disease chancroid, has been shown to associate with dermal collagen fibers within infected skin lesions. Here we describe NcaA, a previously uncharacterized outer membrane protein that is important for
H. ducreyi
collagen binding and host colonization. An
H. ducreyi
strain lacking the
ncaA
gene was impaired in adherence to type I collagen but not fibronectin (plasma or cellular form) or heparin. The mutation had no effect on serum resistance or binding to HaCaT keratinocytes or human foreskin fibroblasts in vitro.
Escherichia coli
expressing
H. ducreyi
NcaA bound to type I collagen, demonstrating that NcaA is sufficient to confer collagen attachment. The importance of NcaA in
H. ducreyi
pathogenesis was assessed using both swine and human experimental models of chancroid. In the swine model, 20% of lesions from sites inoculated with the
ncaA
mutant were culture positive for
H. ducreyi
7 days after inoculation, compared to 73% of wild-type-inoculated sites. The average number of CFU recovered from mutant-inoculated lesions was also significantly reduced compared to that recovered from wild-type-inoculated sites at both 2 and 7 days after inoculation. In the human challenge model, 8 of 30 sites inoculated with wild-type
H. ducreyi
progressed to the pustular stage, compared to 0 of 30 sites inoculated with the
ncaA
mutant. Together these results demonstrate that the collagen binding protein NcaA is required for
H. ducreyi
infection.
Splenic γδ T Cells Regulated by CD4+T Cells Are Required To Control ChronicPlasmodium chabaudiMalaria in the B-Cell-Deficient Mouse
Authors: van der Heyde Henri C. , Batchelder Joan M. , Sandor Matyas , Weidanz William P.
Published: April 2006

Little is known about the function and regulation of splenic γδ T cells during chronicPlasmodium chabaudimalaria. The splenic γδ T-cell population continues to expand, reaching levels equal to 4 times the number of splenocytes in an uninfected mouse. Splenic γδ T cells from JH−/−mice with chronic malaria expressed Vγ1+or Vδ4+in the same ratio as uninfected controls with Vγ1 cells dominating, but the Vγ2 ratio declined about twofold. γδ T cells from G8 mice specific for the TL antigen increased only 2-fold in number, compared with 10-fold in BALB/c controls, but G8 γδ T cells failed to express the B220 activation marker. Elimination of the parasite by drug treatment caused a slow depletion in the number of splenic γδ, CD4+, and CD8+T cells. Following challenge, drug-cured JH−/−mice exhibited nearly identical parasitemia time courses as naïve controls. Depletion of either CD4+T cells or γδ T cells from chronically infected JH−/−mice by monoclonal antibody treatment resulted in an immediate and significant (P< 0.05) exacerbation of parasitemia coupled with a marked decrease in splenic γδ T-cell numbers. The number of CD4+T cells, in contrast, did not decrease in mice after anti-T-cell receptor γδ treatment. The results indicate that cell-mediated immunity against blood-stage malarial parasites during chronic malaria (i) requires the continued presence of blood-stage parasites to remain functional, (ii) is dependent upon both γδ T cells and CD4+T cells, and (iii) lacks immunological memory.
Toll-Like Receptor 2 Is Required for Inflammatory Responses toFrancisella tularensisLVS
Authors: Katz Jannet , Zhang Ping , Martin Michael , Vogel Stefanie N. , Michalek Suzanne M.
Published: April 2006

Francisella tularensis, a gram-negative bacterium, is the etiologic agent of tularemia and has recently been classified as a category A bioterrorism agent. Infections withF. tularensisresult in an inflammatory response that plays an important role in the pathogenesis of the disease; however, the cellular mechanisms mediating this response have not been completely elucidated. In the present study, we determined the role of Toll-like receptors (TLRs) in mediating inflammatory responses toF. tularensisLVS, and the role of NF-κB in regulating these responses. Stimulation of bone marrow-derived dendritic cells from C57BL/6 wild-type (wt) and TLR4−/−but not TLR2−/−mice, with liveF. tularensisLVS elicited a dose-dependent increase in the production of tumor necrosis factor alpha.F. tularensisLVS also induced in a dose-dependent manner an up-regulation in the expression of the costimulatory molecules CD80 and CD86 and of CD40 and the major histocompatibility complex class II molecules on dendritic cells from wt and TLR4−/−but not TLR2−/−mice. TLR6, not TLR1, was shown to be involved in mediating the inflammatory response toF. tularensisLVS, indicating that the functional heterodimer is TLR2/TLR6. Stimulation of dendritic cells withF. tularensisresulted in the activation of NF-κB, which resulted in a differential effect on the production of pro- and anti-inflammatory cytokines. Taken together, our results demonstrate the role of TLR2/TLR6 in the host's inflammatory response toF. tularensisLVS in vitro and the regulatory function of NF-κB in modulating the inflammatory response.
Intestinal Shiga Toxin-Producing
Escherichia coli
Bacteria Mitigate Bovine Leukemia Virus Infection in Experimentally Infected Sheep
Authors: Ferens Witold A. , Cobbold Rowland , Hovde Carolyn J.
Published: April 2006

Ruminants often carry gastrointestinal Shiga toxin (Stx)-producing
Escherichia coli
(STEC). Stxs belong to a large family of ribosome-inactivating proteins (RIPs), found in many plants and some bacteria. Plant RIPs, secreted into extracellular spaces, limit the spread of viruses through plant tissues by penetrating and killing virally infected cells. Previously, we showed Stx activity against bovine leukemia virus (BLV)-infected cells in vitro and hypothesized that STEC bacteria have antiviral activity in ruminant hosts. Here, we investigated the impact of STEC on the initial phases of BLV infection in sheep. Sheep were treated with biweekly oral doses of
E. coli
O157:H7 (an STEC) or an isogenic
stx
mutant strain. A different group of sheep were similarly treated with five naturally occurring ovine STEC isolates or
stx
-negative
E. coli
. Intestinal STEC bacteria were enumerated and identified by standard fecal culture and DNA hybridization. Oral STEC treatment did not always result in carriage of STEC, although many animals consistently presented with >10
4
CFU/g feces. BLV viremia was assessed by spontaneous lymphocyte proliferation (SLP) in cultures of blood mononuclear cells and by syncytium formation in cocultures of the same with F-81 indicator cells. SLP was lower (
P
< 0.05) and syncytia were fewer (
P
 < 0.05) in STEC-treated sheep than in untreated sheep. Both lower SLP and fewer syncytia positively correlated with fecal STEC numbers. Average weight gain post-BLV challenge was higher in STEC-treated sheep than in untreated sheep (
P
< 0.05). These results support the hypothesis that in ruminants, intestinal STEC bacteria have antiviral activity and mitigate BLV-induced disease.
Enterotoxigenicity of Mature 45-Kilodalton and Processed 35-Kilodalton Forms of Hemagglutinin Protease Purified from a Cholera Toxin Gene-Negative
Vibrio cholerae
Non-O1, Non-O139 Strain
Authors: Ghosh A. , Saha D. R. , Hoque K. M. , Asakuna M. , Yamasaki S. , Koley H. , Das S. S. , Chakrabarti M. K. , Pal A.
Published: April 2006

Cholera toxin gene-negative
Vibrio cholerae
non-O1, non-O139 strain PL-21 is the etiologic agent of cholera-like syndrome. Hemagglutinin protease (HAP) is one of the major secretory proteins of PL-21. The mature 45-kDa and processed 35-kDa forms of HAP were purified in the presence and absence of EDTA from culture supernatants of PL-21. Enterotoxigenicities of both forms of HAP were tested in rabbit ileal loop (RIL), Ussing chamber, and tissue culture assays. The 35-kDa HAP showed hemorrhagic fluid response in a dose-dependent manner in the RIL assay. Histopathological examination of 20 μg of purified protease-treated rabbit ileum showed the presence of erythrocytes and neutrophils in the upper part of the villous lamina propria. Treatment with 40 μg of protease resulted in gross damage of the villous epithelium with inflammation, hemorrhage, and necrosis. The 35-kDa form of HAP, when added to the lumenal surface of rat ileum loaded in an Ussing chamber, showed a decrease in the intestinal short-circuit current and a cell rounding effect on HeLa cells. The mature 45-kDa form of HAP showed an increase in intestinal short-circuit current in an Ussing chamber and a cell distending effect on HeLa cells. These results show that HAP may play a role in the pathogenesis of PL-21.
Nonclassical Pathway ofPseudomonas aeruginosaDNA-Induced Interleukin-8 Secretion in Cystic Fibrosis Airway Epithelial Cells
Authors: Delgado Mónica A. , Poschet Jens F. , Deretic Vojo
Published: April 2006

Pseudomonas aeruginosais a critical colonizer of the respiratory tract in cystic fibrosis. The chronic infections with this microorganism contribute to excessive inflammation and progressive lung damage in cystic fibrosis patients. The full repertoire ofPseudomonasproducts that promote inflammation in the cystic fibrosis lung is not known. Here we show thatP. aeruginosaDNA released from the bacterium, but not human DNA from epithelial cells orEscherichia coliDNA, displays proinflammatory properties and induces human respiratory epithelial cells to secrete interleukin-8 (IL-8), a key chemokine causing excessive neutrophil infiltration in the cystic fibrosis lung. IL-8 secretion was not due to an increase in NF-κB- or activator protein-1-dependent IL-8 promoter transcription, but instead depended on p38 and Erk mitogen-activated protein kinases. No secretion of IL-8 was observed using conventional Toll-like receptor 9 ligands (CpG oligonucleotides), although it could be demonstrated that parts of the Toll-like receptor 9-signaling pathway were functional, since class B and C CpG oligonucleotide ligands stimulated production of RANTES chemokine. The IL-8 secretion in response toP. aeruginosaDNA was decreased by treatments that inhibit acidification of intracellular organelles, using chloroquine, a pH-neutralizing compound, or bafilomycin A1, an inhibitor of vacuolar H+-ATPase. These data indicate that DNA released fromP. aeruginosaduring chronic infections may significantly contribute to the proinflammatory processes in cystic fibrosis. Our findings also show that treatments with drugs diminishing organellar acidification may reduce the inflammatory response in cystic fibrosis.
Mutational Analysis of the
Escherichia coli melR
Gene Suggests a Two-State Concerted Model To Explain Transcriptional Activation and Repression in the Melibiose Operon
Authors: Kahramanoglou Christina , Webster Christine L. , el-Robh Mohamed Samir , Belyaeva Tamara A. , Busby Stephen J. W.
Published: April 2006

Transcription of the
Escherichia coli melAB
operon is regulated by the MelR protein, an AraC family member whose activity is modulated by the binding of melibiose. In the absence of melibiose, MelR is unable to activate the
melAB
promoter but autoregulates its own expression by repressing the
melR
promoter. Melibiose triggers MelR-dependent activation of the
melAB
promoter and relieves MelR-dependent repression of the
melR
promoter. Twenty-nine single amino acid substitutions in MelR that result in partial melibiose-independent activation of the
melAB
promoter have been identified. Combinations of different substitutions result in almost complete melibiose-independent activation of the
melAB
promoter. MelR carrying each of the single substitutions is less able to repress the
melR
promoter, while MelR carrying some combinations of substitutions is completely unable to repress the
melR
promoter. These results argue that different conformational states of MelR are responsible for activation of the
melAB
promoter and repression of the
melR
promoter. Supporting evidence for this is provided by the isolation of substitutions in MelR that block melibiose-dependent activation of the
melAB
promoter while not changing melibiose-independent repression of the
melR
promoter. Additional experiments with a bacterial two-hybrid system suggest that interactions between MelR subunits differ according to the two conformational states.
Characterization of the Transcriptional Activators SalA and SyrF, Which Are Required for Syringomycin and Syringopeptin Production byPseudomonas syringaepv. syringae
Authors: Wang Nian , Lu Shi-En , Records Angela R. , Gross Dennis C.
Published: April 2006

Production of the phytotoxins syringomycin and syringopeptin byPseudomonas syringaepv. syringae is controlled by the regulatory genessalAandsyrF. Analysis with 70-mer oligonucleotide microarrays established that thesyr-sypgenes responsible for synthesis and secretion of syringomycin and syringopeptin belong to the SyrF regulon. Vector pMEKm12 was successfully used to express both SalA and SyrF proteins fused to a maltose-binding protein (MBP) inEscherichia coliandP. syringaepv. syringae. Both the MBP-SalA and MBP-SyrF fusion proteins were purified by maltose affinity chromatography. Gel shift analysis revealed that the purified MBP-SyrF, but not the MBP-SalA fusion protein, bound to a 262-bp fragment of thesyrB1promoter region containing thesyr-sypbox. Purified MBP-SalA caused a shift of a 324-bp band containing the putativesyrFpromoter. Gel filtration analysis and cross-linking experiments indicated that both SalA and SyrF form homodimers in vitro. Overexpression of the N-terminal regions of SalA and SyrF resulted in decreased syringomycin production by strain B301D and reduced levels of β-glucuronidase activities of thesypA::uidAandsyrB1::uidAreporters by 59% to 74%. The effect of SalA on the expression of thesyr-sypgenes is mediated by SyrF, which activates thesyr-sypgenes by directly binding to the promoter regions. Both SalA and SyrF resemble other LuxR family proteins in dimerization and interaction with promoter regions of target genes.
Posttranscriptional Control of the
Salmonella enterica
Flagellar Hook Protein FlgE
Authors: Lee Hee Jung , Hughes Kelly T.
Published: April 2006

Previous work suggested that the FlgE (flagellar hook subunit) protein in
Salmonella enterica
serovar Typhimurium was posttranscriptionally regulated in response to the stage of flagellar assembly. Specifically, the FlgE protein could be detected in flagellar mutants defective at the stages of assembly before or after rod assembly but not in rod assembly mutants, yet
flgE
mRNA levels were unaffected. To elucidate posttranscriptional mechanisms involved in the coupling of
flgE
gene expression to hook assembly, the RNA sequences at the 5′ and 3′ ends of the
flgE
-containing mRNA processed from the large
flgBCDEFGHIJKL
operon were determined by rapid amplification of cDNA ends, and secretion of the FlgE protein in different flagellar assembly mutant strains was analyzed. The sequences 5′ and 3′ of the
flgE
gene where RNA processing occurred was within 15 bases upstream of the
flgD
stop codon and at bases 145 to 147 downstream of the
flgF
start codon, respectively. The ribosome binding site of the
flgD
gene was found to be inhibitory to
flgE
translation in strains deleted for the upstream
flgD
gene, unless the region 15 bases upstream of the
flgD
stop codon was present. Secretion of FlgE into the periplasm was monitored using β-lactamase (Bla) fusions as a periplasm-specific reporter, which conferred resistance to ampicillin when FlgE-Bla was secreted into the periplasm. Using this assay, we found that the effect of rod assembly mutants on FlgE levels was due to FlgE turnover in the periplasm and that the FliE rod component protein was required for efficient FlgE-Bla secretion.
Sll0254 (CrtL
diox
) Is a Bifunctional Lycopene Cyclase/Dioxygenase in Cyanobacteria Producing Myxoxanthophyll
Authors: Mohamed Hatem E. , Vermaas Wim F. J.
Published: April 2006

Upon depletion of Sll0254 in
Synechocystis
sp. strain PCC 6803, cyclized carotenoids were replaced by linear, relatively hydrophilic carotenoids, and the amount of the two photosystems decreased greatly. Full segregants of the sll0254 deletion in
Synechocystis
were not obtained, implying that this gene is essential for survival, most likely to allow normal cell division. The N-terminal half of Sll0254 has limited similarity to the family of lycopene cyclases, has an additional dehydrogenase motif near the N terminus, and is followed by a Rieske 2Fe-2S center sequence signature. To test whether Sll0254 serves as a lycopene cyclase in
Synechocystis
, the corresponding gene was expressed in
Escherichia coli
strains that can produce lycopene or neurosporene. In the presence of Sll0254 these linear carotenoids were converted into cyclized, relatively hydrophilic pigments, with masses consistent with the introduction of two hydroxyl groups and with spectra indicative of only small changes in the number of conjugated double bonds. This suggests that Sll0254 catalyzes formation of oxygenated, cyclized carotenoids. We interpret the appearance of the hydroxyl groups in the carotenoids to be due to dioxygenase activity involving the Rieske 2Fe-2S center and the additional dehydrogenase domain. This dioxygenase activity is required in the myxoxanthophyll biosynthesis pathway, after or concomitant with cyclization on the other end of the molecule. We interpret Sll0254 to be a dual-function enzyme with both lycopene cyclase and dioxygenase activity and have named it CrtL
diox
.
Risk of affective and stress related disorders among employees in human service professions
Authors: Wieclaw J , Agerbo E , Mortensen P B , Bonde J P
Published: April 2006

Objectives:To examine the risk of affective and stress related disorders among men and women employed in human service professions.

Methods:Population based case-control study using data from national registers. Cases (n = 28 971) were identified in the Danish Psychiatric Central Research Register among all hospitalised patients and outpatients aged 18–65 who received a first time ever diagnosis of affective (ICD-10, F30–39) or stress related (ICD-10, F40–48) disorder from 1 January 1995 to 31 December 1998. Each case was assigned five never admitted referents (n = 144 855) of the same gender and age, randomly drawn from a 5% sample of the Danish population obtained from Statistics Denmark’s Integrated Database for Labour Market Research. Occupation held the year before matching was classified according to the Danish version of the International Classification of Occupation. Health care, education, social work, and customer services were defined as human service professions and constituted 21% of all employed in the study. Adjusted risks (hazard ratios) relative to all other occupations were calculated for 24 human service occupations.

Results:The relative risk of depression in human service professions was 1.35 (95% CI 1.24 to 1.47) for women and 1.49 (95% CI 1.29 to 1.73) for men. The risk of stress was 1.18 (95% CI 1.11 to 1.26) for women and 1.49 (95% CI 1.32 to 1.67) for men. Specific professions contributed differentially to the magnitude of risk, with education and social services displaying the highest risks. No increase in risks was found in customer service occupations. Gender was a significant modifying factor with the highest risk levels in men.

Conclusions:There was a consistent association between employment in human service occupations and the risk of affective and stress related disorders. Risks were highest for men working in these typically female professions. More work is needed to distinguish work hazards from effects attributable to selection mechanisms and personality characteristics.
CONNECTION BETWEEN THE LOOP VARIABLE FORMALISM AND THE OLD COVARIANT FORMALISM FOR THE OPEN BOSONIC STRING
Authors: SATHIAPALAN B.
Published: April 2006

The gauge-invariant loop variable formalism and old covariant formalism for bosonic open string theory are compared in this paper. It is expected that for the free theory, after gauge fixing, the loop variable fields can be mapped to those of the old covariant formalism in bosonic string theory, level by level. This is verified explicitly for the first two massive levels. It is shown that (in the critical dimension) the fields, constraints and gauge transformations can all be mapped from one to the other. Assuming this continues at all levels one can give general arguments that the tree S-matrix (integrated correlation functions for on-shell physical fields) is the same in both formalisms and therefore they describe the same physical theory (at tree level).
MATTER–ANTIMATTER ASYMMETRY GENERATED AT LOW TEMPERATURES
Authors: CARMONA JOSÉ MANUEL , CORTÉS JOSÉ LUIS , DAS ASHOK , GAMBOA JORGE , MÉNDEZ FERNANDO
Published: April 2006

We explore the possibility of having baryogenesis at temperatures below any dilution mechanism, such as inflation or sphaleron effects at the electroweak transition. We find that large infrared CPT violation (CPTV) effects are a necessary ingredient for such a baryogenesis. We give an explicit example of a theory supporting this scenario at the kinematical level in which such CPTV effects are suppressed at the level of CPT tests based on mass differences between particle and antiparticle.
Expression of Constitutively Active Angiotensin Receptors in the Rostral Ventrolateral Medulla Increases Blood Pressure
Authors: Allen Andrew M. , Dosanjh Jaspreet K. , Erac Marco , Dassanayake Sashikala , Hannan Ross D. , Thomas Walter G.
Published: April 2006

Angiotensin type 1A (AT
1A
) receptors are expressed within the rostral ventrolateral medulla, and microinjections of angiotensin II into this region increase sympathetic vasomotor tone. To determine the effect of sustained increases in AT
1A
receptor density or activity in rostral ventrolateral medulla, we used radiotelemetry to monitor blood pressure in conscious rats before and after bilateral microinjection into the rostral ventrolateral medulla of adenoviruses encoding the wild-type AT
1A
receptor or a constitutively active version of the receptor (Asn
111
Gly, [N111G]AT
1A
). The constitutively active receptor signals in the absence of angiotensin II. Adenovirus-directed receptor expression was extensively characterized both in vitro and in vivo. We established that adenoviral infection was limited to the rostral ventrolateral medulla and that receptor expression was sustained for ≥10 days; we also observed that adenoviral transgene expression occurs in glia, with no transgene expression observed in neurons of the rostral ventrolateral medulla. Rats receiving the wild-type AT
1A
receptor showed no change in blood pressure, whereas animals receiving the [N111G]AT
1A
receptor displayed an increase in blood pressure that persisted for 3 to 4 days before returning to basal levels. These data indicate that increased AT
1A
receptor activity (not just overexpression) is a primary determinant of efferent drive from rostral ventrolateral medulla and reveal counterregulatory processes that moderate AT
1A
receptor actions at this crucial relay point. More importantly, they imply that constitutive receptor signaling in glia of the rostral ventrolateral medulla can modulate the activity of adjacent neurons to change blood pressure.
Transposition of Great Arteries Is Associated With Increased Carotid Artery Stiffness
Authors: Mersich Beatrix , Studinger Peter , Lenard Zsuzsanna , Kadar Krisztina , Kollai Mark
Published: April 2006

Transposition of great arteries is the consequence of abnormal aorticopulmonary septation. Animal embryonic data indicate that septation and elastogenesis are related events, but human and clinical data are not available. We tested the hypothesis that large artery elastic function was impaired in patients with transposition of great arteries. We studied 34 patients aged 9 to 19 years, 12±3 years after atrial switch operation; 14 patients aged 7 to 9 years, 8±1 years after arterial switch operation; and 108 healthy control subjects matched for age. Carotid artery diastolic diameter and pulsatile distension were determined by echo wall-tracking; carotid blood pressure was measured by tonometry. Systolic pressure was higher and diastolic pressure was lower in patients than in controls. Patients with atrial and arterial switch repair were compared with their respective controls by 2-factor ANOVA. For patients with atrial switch repair versus control, stiffness index β was 4.9±1.5 versus 3.1±1.0 (
P
<0.001); for patients witch arterial switch versus control, stiffness index β was 3.8±1.1 versus 2.1±0.6 (
P
<0.001). Similar differences were observed for carotid compliance, distensibility, and incremental elastic modulus as well. The interaction term was not significant for any of the elastic variables, indicating that carotid stiffening was a characteristic of the condition and not the consequence of different hemodynamics. Carotid artery is markedly stiffer in patients, suggesting that impaired elastogenesis may constitute part of the congenital abnormality. Since carotid artery stiffness has been established as an independent cardiovascular risk factor, this condition may have consequences in the clinical management of these patients.
Angiotensin II Decreases the Renal MRI Blood Oxygenation Level–Dependent Signal
Authors: Schachinger Hartmut , Klarhöfer Markus , Linder Lilly , Drewe Jürgen , Scheffler Klaus
Published: April 2006

Acute experimental reduction of renal blood flow decreases the renal blood oxygenation level–dependent (BOLD) MRI signal in animals. Angiotensin II also reduces renal blood flow, but the ability of BOLD MRI to dynamically detect this response has not yet been investigated in humans. Six healthy male volunteers underwent an individual dose-finding study to identify the intravenous doses of angiotensin II, norepinephrine, and sodium nitroprusside necessary to induce a 15-mm Hg peak mean arterial blood pressure change. MRI studies followed within 3 weeks, when angiotensin II (8.8±1.4 ng/kg), norepinephrine (52±12 ng/kg), and sodium nitroprusside (2.0±0.3 μg/kg) were given twice in an unblocked, randomized sequence while imaging experiments were performed on a 1.5-T Siemens Sonata. A multiecho echo-planar imaging sequence was used to acquire T2* maps with a temporal resolution of 1 respiratory cycle. Averaged over a renal cortex dominated region of interest, angiotensin II caused a shortening of T2* between 6% and 10%. Sodium nitroprusside and norepinephrine, although of equal potency concerning blood pressure responses, did not alter the renal BOLD signal. The renal BOLD response to angiotensin II appeared with short onset latency (as early as 10 seconds after peripheral intravenous angiotensin II bolus administration) suggesting that this response is a consequence of altered perfusion rather than increased renal oxygen consumption. The methods described here are suitable to assess renal responsiveness to angiotensin II and may, thus, be of great value in human hypertension research.
Effect of Low-Density Lipoprotein Cholesterol on Angiotensin II Sensitivity
Authors: van der Linde Nicole A.J. , Sijbrands Eric J.G. , Boomsma Frans , van den Meiracker Anton H.
Published: April 2006

Increased angiotensin II (Ang II) sensitivity predisposes to hypertension and plaque instability. Raised low-density lipoprotein cholesterol (LDL-c) may increase Ang II sensitivity, but evidence in humans for this effect of LDL-c is limited. In 28, healthy, nonsmoking subjects, aged 30±8 years, with familial hypercholesterolemia, we determined the difference in infusion rate of Ang II and norepinephrine required to increase systolic blood pressure by 20 mm Hg (Pd-20) after 4 weeks of placebo and fluvastatin 80 mg daily in a randomized, double-blind, placebo-controlled, crossover study. Before infusions were started, fasting blood samples were taken to measure lipids. After 4 weeks of placebo, the mean LDL-c concentration was 6.3±1.4 mmol/L. The average decrease of LDL-c was 1.7±0.7 mmol/L after 4 weeks of fluvastatin (
P
<0.001). The mean Pd-20 for Ang II increased by 1.28 ng/kg per minute (95% CI, 2.05 to 0.50;
P=
0.002) on fluvastatin, corresponding with a 26% decrease in Ang II sensitivity. Ang II sensitivity, however, remained increased compared with normocholesterolemic controls. The Pd-20 values for norepinephrine were unaffected by fluvastatin. The present study in healthy, young subjects with isolated hypercholesterolemia shows an increased sensitivity to Ang II that partly can be restored by LDL-c–lowering therapy. These findings indicate that LDL-c levels directly influence Ang II sensitivity.
Use of First- and Second-Generation Cyclooxygenase-2–Selective Nonsteroidal Antiinflammatory Drugs and Risk of Acute Myocardial Infarction
Authors: Andersohn Frank , Suissa Samy , Garbe Edeltraut
Published: April 2006

Background—

The cardiovascular safety of cyclooxygenase (COX)-2–selective nonsteroidal antiinflammatory drugs (NSAIDs) has come under scrutiny after the withdrawal of rofecoxib and halting of the Adenoma Prevention with Celecoxib trial. Whether the newer second-generation COX-2 inhibitors (etoricoxib, valdecoxib) also increase the cardiovascular risk is unknown.

Methods and Results—

We performed a nested case-control study in a cohort of 486 378 persons registered within the United Kingdom General Practice Research Database with at least 1 prescription of an NSAID between June 1, 2000, and October 31, 2004. A total of 3643 cases with acute myocardial infarction (AMI) were matched to 13 918 controls on age, sex, year of cohort entry, and general practice. Rate ratios (RRs) of AMI associated with use of COX-2–selective and –nonselective NSAIDs were calculated. Current use of etoricoxib was associated with a 2.09-fold (95% confidence interval [CI], 1.10 to 3.97) risk of AMI compared with no use of NSAIDs during the prior year. Current use of rofecoxib (RR=1.29; 95% CI, 1.02 to 1.63), celecoxib (RR=1.56; 95% CI, 1.22 to 2.00), and diclofenac (RR=1.37; 95% CI, 1.17 to 1.59) also significantly increased the AMI risk. For current use of valdecoxib, the RR was 4.60 (95% CI, 0.61 to 34.51). RRs appeared to increase with higher daily doses of COX-2 inhibitors and were also increased in patients without major cardiovascular risk factors.

Conclusions—

Our study supports the hypothesis that the elevated risk of AMI is a class effect of COX-2 inhibitors. The increase in risk appears to be dose dependent, but further data are needed to verify this observation.
Numbers 15
Authors: Gorringe Tim
Published: April 2006

Numbers 15 seems to be a collection of disparate material dealing with sacrifice and ritual offences, but looked at more closely it has many connections with the contemporary world, not least in our understanding of the treatment of economic migrants and offenders.
Fatigue Life Prediction of Pultruded E-glass/Polyurethane Composites
Authors: Qiao Pizhong , Yang Mijia
Published: April 2006

In this article, the tension–tension fatigue behavior of newly developed pultruded E-glass/polyurethane composites is characterized, and an improved model for fatigue life prediction including the effects of stress ratio, frequency, and mean stress as the testing parameters is proposed. The proposed non-dimensional analysis is in good agreement with the predictions of existing available fatigue data and present testing data. The model is consistent with the Goodman line relationship and has a clear physical meaning. The fatigue test data of E-glass/polyurethane composites are analyzed using the proposed model, and they are compared with other common E-glass fiber-reinforced plastic composites. It indicates that the E-glass/polyurethane composites are more fatigue sensitive but comparable to other fiber-reinforced plastic composites in their fatigue behaviors. The effects of stress ratio, frequency, and mean stress on fatigue life of E-glass/polyurethane composites are studied and discussed. The corresponding S–N curve and its bounds based on 95% confidence are provided for the pultruded E-glass/polyurethane composites. The present fatigue model can be used as a useful tool to characterize the effects of various parameters on the fatigue behavior of fiber-reinforced plastic composites, and it provides the fatigue life prediction for newly developed pultruded E-glass/polyurethane composites.
Improvements to Single-Fault Isolation Using Estimated Parameters
Authors: Samantaray A. K. , Ghoshal S. K. , Chakraborty S. , Mukherjee A.
Published: April 2006

A method for finer fault isolation or localization in the model-based fault detection and isolation (FDI) paradigm is developed using parallely computed bond graph models. Many of the existing modelbased FDI methods are based on the evaluation of model consistency expressed in terms of analytical redundancy relations (ARR). These evaluations lead to residuals, and a number of sensors are to be installed in the plant to generate independent signatures needed for fault isolation. However, all the possible faults may not be isolable with the available instrumentation, and it is sometimes expensive or technically impossible to install necessary sensors in the plant to physically measure each and every state. In such situations, all component faults may not be uniquely isolated. However, a unique fault parameter subspace can be identified. One of the possible solutions, as proposed in this article, is to estimate parameters of that subspace from the ARR by assuming a single-fault hypothesis and then to incorporate the estimated values in separate models to run parallel with the plant during the fault. Thereafter, comparison of model behaviors leads to localization of the faulty parameters. This method is applied to an example system.
Integrating Dynamic and Geometry Model Components through Ontology-Based Inference
Authors: Park Minho , Fishwick Paul A.
Published: April 2006

Modeling techniques tend to be found in isolated communities: geometry models in computer-aided design (CAD) and computer graphics, dynamic models in computer simulation, and information models in information technology. When models are included within the same digital environment, the ways of connecting them together seamlessly and visually are not well known even though elements from each model have many commonalities. A model is required to be able to connect models together in the interface; however, creating such models is time-consuming. This article addresses this deficiency by studying specific ways in which models can be interconnected within the same 3D space through effective ontology construction and human interaction techniques. The authors have developed a method for automatically constructing a human-computer interface model (i.e., which is termed an interaction model) from an ontology for an example physical environment. The work to date has resulted in an environment based on a 3D modeling and animation package, permitting users to explore dynamic model structure through interactions with geometric scene structure.
Missteps in Team Leadership
Authors: Sanders Mavis G.
Published: April 2006

This study explores novice teachers’ experiences as team leaders for school-community partnerships. Six focal teachers who were enrolled in an MA program in teacher development and leadership were recruited for the study. The focal teachers volunteered to serve as leaders of a reading-focused community involvement activity as members of their schools’ improvement teams. Based on the focal teachers’ experiences, this article describes obstacles to collaboration and three responses to these obstacles (neglecting the process to get the job done, doing too much with too little, and failing to follow through) that influenced the outcomes of the activities. These findings are discussed in light of current school reform efforts that rely on team structures and approaches.
Labour Law Reform in Turkey in the 2000s: The Devil is Not Just in the Detail But Also in the Legal Texts
Authors: Özdemir Ali Murat , Yücesan-Özdemir Gamze
Published: April 2006

This study examines how the balance of power has changed between the parties in industrial relations in the area of individual labour law in Turkey in the 2000s. It analyses the new Labour Act of Turkey with regard to changes in the notion of subordination and changing working conditions. It presents a definition of ‘the new employer’ – as the representative of the flexible company.
Social Pacts on the Road to EMU: A Comparison of the Italian and Polish Experiences
Authors: Meardi Guglielmo
Published: April 2006

In the new EU member states, tripartite national-level social pacts have been promoted as a preferred and effective instrument for a rapid and relatively painless fulfilment of the Maastricht criteria, following the example of many of the old member states in the 1990s, and notably Italy. But such policy advice is not based on careful comparisons. By comparing Poland and Italy, this article undermines the dominant view that the failure of concertation attempts in Poland is mostly due to trade union politicization. The comparative test with Italy, a country with equally politicized trade unions, and where, by contrast, important social pacts have been signed, suggests that divergent employer strategies and organization are at least an equally important factor. Additionally, the study provides a more mixed assessment of the Italian social pacts.
Corruption, Democracy, and Economic Growth
Authors: Drury A. Cooper , Krieckhaus Jonathan , Lusztig Michael
Published: April 2006

Scholars have long suspected that political processes such as democracy and corruption are important factors in determining economic growth. Studies show, however, that democracy has only indirect effects on growth, while corruption is generally accepted by scholars as having a direct and negative impact on economic performance. We argue that one of democracy's indirect benefits is its ability to mitigate the detrimental effect of corruption on economic growth. Although corruption certainly occurs in democracies, the electoral mechanism inhibits politicians from engaging in corrupt acts that damage overall economic performance and thereby jeopardize their political survival. Using time-series cross-section data for more than 100 countries from 1982–97, we show that corruption has no significant effect on economic growth in democracies, while non-democracies suffer significant economic harm from corruption.
An evaluation of tactile directional symbols
Authors: McCallum Don , Ungar Simon , Jehoel Sandra
Published: April 2006

Symbols that could effectively designate direction have the potential to show routes, geographic phenomena, aid scientific explanation and generally enhance understanding of tactile maps and diagrams. In this study, 41 tactile symbols, including subsets of arrow symbols and stair symbols, were investigated for effectiveness at indicating direction. The symbols were presented to blind or blindfolded participants, and qualitative and quantitative responses regarding the symbol orientation and meaning were recorded. The arrow symbols with the greatest agreement across participants as to which direction the symbol intended to convey were basic arrows and the arrowhead. In the case of a line with a saw-tooth surface profile that felt rough when traced by the finger in one direction and smooth in the opposite, participants were split between those intuitively thinking the rough or the smooth was the direction being indicated. Stair symbols with a greater degree of threedimensionality gave marginally increased agreement as to which way was up.
Quantification of Macrophage Viability and Inflammatory Response to Dental Bonding Resins
Authors: Bailey Leeann O. , Weir Michael D. , Washburn Newell R.
Published: April 2006

This study presented a well-characterized biocompatibility profile of dental bonding agents in a mouse macrophage in vitro model. The cellular response to four different formulations of dental bonding resins and the cell viability was determined. Materials were prepared by photopolymerization and the unreacted monomers were extracted in a buffered medium. Murine macrophages were incubated in the extract medium for 24 h. Cellular viability was assessed by fluorescence microscopy and Wst-1 assay, while flow cytometry was used to quantify the apoptotic response. As an indicator of inflammatory responses, real-time polymerase chain reaction was utilized to quantify elevated cytokine production. These responses were monitored by quantifying the levels of tumor necrosis factor alpha (TNFα) and interleukin-1 β (IL-1β) produced by the cells. Murine macrophage cells exposed to the unfilled resin systems containing glycidyl ether of bisphenol A (Bis-GMA) and 2-hydroxyethyl methacrylate (HEMA) had the most adverse response and cells exposed to the filled Bis-GMA and HEMA resin system were the most viable at photopolymerization times. Other resin systems displayed intermediate levels of viability when compared with the untreated control. The levels of IL-1β were significantly elevated in all samples.
A Novel Approach to Study Enzymatic Degradation of Ter-polymeric Beads for Gastrointestinal Drug Delivery: Synthesis and Characterization
Authors: Bajpai S. K. , Saxena Sutanjay , Dubey Seema
Published: April 2006

The α-amylase induced enzymatic degradation of terpolymeric beads, composed of calcium alginate, starch and poly(ethylene) glycol, were studied for gastrointestinal drug delivery. The beads demonstrated faster degradation with increased enzyme activity in the range 0.64 to 2.24IU/mL. A linear relationship of the degradation rates and corresponding enzyme concentration indicate that degradation is governed by Michaelis-Menten kinetics. The degradation rate was enhanced with increases in starch content in the beads. The smaller value of KM (3.15 × 10−5 mol−1 dm−3) indicated higher enzyme-substrate affinity. The beads crosslinked with barium ions demonstrated slower degradation due to a higher degree of crosslinking in the beads. With increases in initial water content, the degradation was found to increase. In order to incorporate in vivo GI conditions, the degradation was also studied using a flow through diffusion cell (FTDC). The hydrogel beads exhibited slower degradation by FTDC compared to traditional in vitro methods and the degradation was dependent on the nature of the filler particles used in the diffusion cell.
Preparation and Evaluation of Porous Chitosan/Collagen Scaffolds for Periodontal Tissue Engineering
Authors: Peng Lin , Cheng Xiang Rong , Wang Jia Wei , Xu Dong Xuan , Wang Ge
Published: April 2006

The wide array of periodontal tissue engineering applications has demonstrated the need for appropriate biodegradable materials. Porous chitosan/collagen – a natural derivative composite – scaffolds could be a candidate. In this study, differently proportioned porous chitosan/collagen scaffolds were prepared by controlled freezing and lyophylization of corresponding composite solutions. The scaffolds were investigated via aperture, porosity, swelling behavior and cell-mediated contraction testing. The morphology and distribution of human periodontal ligament cells (PDLCs) on these threedimensional scaffolds were investigated by SEM and CLSM. Compared to a single component scaffold, the addition of collagen to chitosan decreased the mean aperture, increased the swelling ability and the addition of chitosan to collagen decreased the contraction. The adherence and growth of PDLCs cultured within the chitosan/collagen scaffolds were better than on single chitosan or collagen scaffolds. It appears that chitosan/collagen composites are promising scaffold materials for periodontal tissue engineering.