bluuebunny/crossref_metadata_2025 huggingface dataset:
Immune Response, Ciprofloxacin Activity, and Gender Differences after Human Experimental Challenge by Two Strains of Enterotoxigenic
Escherichia coli
Authors: Coster T. S. , Wolf M. K. , Hall E. R. , Cassels F. J. , Taylor D. N. , Liu C. T. , Trespalacios F. C. , DeLorimier A. , Angleberger D. R. , McQueen C. E.
Published: December 2006

In order to test vaccines against enterotoxigenic
Escherichia coli
(ETEC)-induced diarrhea, challenge models are needed. In this study we compared clinical and immunological responses after North American volunteers were orally challenged by two ETEC strains. Groups of approximately eight volunteers received 10
9
or 10
10
CFU of
E. coli
B7A (LT
+
ST
+
CS6
+
) or 10
8
or 10
9
CFU of
E. coli
H10407 (LT
+
ST
+
CFA/I
+
). About 75% of the volunteers developed diarrhea after challenge with 10
10
CFU B7A or either dose of H10407. B7A had a shorter incubation period than H10407 (
P
= 0.001) and caused milder illness; the mean diarrheal output after H10407 challenge was nearly twice that after B7A challenge (
P
= 0.01). Females had more abdominal complaints, and males had a higher incidence of fever. Ciprofloxacin generally diminished or stopped symptoms and shedding by the second day of antibiotic treatment, but four subjects shed for one to four additional days. The immune responses to colonization factors CS6 and colonization factor antigen I (CFA/I) and to heat-labile toxin (LT) were measured. The responses to CFA/I were the most robust responses; all volunteers who received H10407 had serum immunoglobulin A (IgA) and IgG responses, and all but one volunteer had antibody-secreting cell (ASC) responses. One-half the volunteers who received B7A had an ASC response to CS6, and about one-third had serum IgA or IgG responses. Despite the differences in clinical illness and immune responses to colonization factors, the immune responses to LT were similar in all groups and were intermediate between the CFA/I and CS6 responses. These results provide standards for immune responses after ETEC vaccination.
Protective and Immunochemical Activities of Monoclonal Antibodies Reactive with theBacillus anthracisPolypeptide Capsule
Authors: Kozel Thomas R. , Thorkildson Peter , Brandt Suzanne , Welch William H. , Lovchik Julie A. , AuCoin David P. , Vilai Julpohng , Lyons C. Rick
Published: December 2006

Bacillus anthracisis surrounded by a polypeptide capsule composed of poly-gamma-d-glutamic acid (γDPGA). In a previous study, we reported that a monoclonal antibody (MAb F26G3) reactive with the capsular polypeptide is protective in a murine model of pulmonary anthrax. The present study examined a library of six MAbs generated from mice immunized with γDPGA. Evaluation of MAb binding to the capsule by a capsular “quellung” type reaction showed a striking diversity in capsular effects. Most MAbs produced a rim type reaction that was characterized by a sharp increase followed directly by a decrease in refractive index at the capsular edge. Some MAbs produced a second capsular reaction well beneath the capsular edge, suggesting complexity in capsular architecture. Binding of MAbs to soluble γDPGA was assessed by a fluorescence perturbation assay in which a change in the MAb intrinsic fluorescence produced by ligand binding was used as a reporter for antigen-antibody interaction. The MAbs differed considerably in the complexity of the binding curves. MAbs producing rim type capsule reactions typically produced the more complex binding isotherms. Finally, the protective activity of the MAbs was compared in a murine model of pulmonary anthrax. One MAb was markedly less protective than the remaining five MAbs. Characteristics of the more protective MAbs included a relatively high affinity, an immunoglobulin G3 isotype, and a complex binding isotherm in the fluorescence perturbation assay. Given the relatively monotonous structure of γDPGA, the results demonstrate a striking diversity in the antigen binding behavior of γDPGA antibodies.
Vβ1
+
Jβ1.1
+
/Vα2
+
Jα49
+
CD4
+
T Cells Mediate Resistance against Infection with
Blastomyces dermatitidis
Authors: Wüthrich Marcel , Filutowicz Hanna I. , Allen Holly L. , Deepe George S. , Klein Bruce S.
Published: December 2006

Immunization with a cell wall/membrane (CW/M) and yeast cytosol extract (YCE) crude antigen from
Blastomyces dermatitidis
confers T-cell-mediated resistance against lethal experimental infection in mice. We isolated and characterized T cells that recognize components of these protective antigens and mediate protection. CD4
+
T-cell clones elicited with CW/M antigen adoptively transferred protective immunity when they expressed a Vα2
+
Jα49
+
/Vβ1
+
Jβ1.1
+
heterodimeric T-cell receptor (TCR) and produced high levels of gamma interferon (IFN-γ). In contrast, Vβ8.1/8.2
+
CD4
+
T-cell clones that were reactive against CW/M and YCE antigens and produced little or no IFN-γ either failed to mediate protection or exacerbated the infection depending on the level of interleukin-5 expression. Thus, the outgrowth of protective T-cell clones against immunodominant antigens of
B. dermatitidis
is biased by a combination of the TCR repertoire and Th1 cytokine production.
Temporal Quorum-Sensing Induction Regulates
Vibrio cholerae
Biofilm Architecture
Authors: Liu Zhi , Stirling Fiona R. , Zhu Jun
Published: December 2006

Vibrio cholerae
, the pathogen that causes cholera, also survives in aqueous reservoirs, probably in the form of biofilms. Quorum sensing negatively regulates
V. cholerae
biofilm formation through HapR, whose expression is induced at a high cell density. In this study, we show that the concentration of the quorum-sensing signal molecule CAI-1 is higher in biofilms than in planktonic cultures. By measuring
hapR
expression and activity, we found that the induction of quorum sensing in biofilm-associated cells occurs earlier. We further demonstrate that the timing of
hapR
expression is crucial for biofilm thickness, biofilm detachment rates, and intestinal colonization efficiency. These results suggest that
V. cholerae
is able to regulate its biofilm architecture by temporal induction of quorum-sensing systems.
Fully Virulent
Bacillus anthracis
Does Not Require the Immunodominant Protein BclA for Pathogenesis
Authors: Bozue J. , Cote C. K. , Moody K. L. , Welkos S. L.
Published: December 2006

The BclA protein is the immunodominant epitope on the surface of
Bacillus anthracis
spores; however, its roles in pathogenesis are unclear. We constructed a BclA deletion mutant (
bclA
) of the fully virulent Ames strain. This derivative retained full virulence in several small-animal models of infection despite the
bclA
deletion.
Dendritic Cell-Derived Exosomes Express a
Streptococcus pneumoniae
Capsular Polysaccharide Type 14 Cross-Reactive Antigen That Induces Protective Immunoglobulin Responses against Pneumococcal Infection in Mice
Authors: Colino Jesus , Snapper Clifford M.
Published: December 2006

Exosomes activate T cells in vivo, but whether exosomes are able to induce humoral immune responses is still unknown. We found that dendritic cells, but not other immune cells, constitutively release an exosome-associated glycoconjugate that is cross-reactive with the capsular polysaccharide of
Streptococcus pneumoniae
type 14 (Cps14-CRA). Cps14-CRA was localized to the cholesterol-enriched microdomains or rafts of the exosomes and was mapped to the β1→6 branched
N
-acetyl-lactosamine derivatives of the Cps14-CRA. Injection of CFA-primed naive mice with purified dendritic cell exosomes induced immunoglobulin (Ig) anti-Cps14 responses composed predominantly of IgM, IgG3, and IgG1. These responses were associated with protection against a lethal challenge with live
S. pneumoniae
type 14, but not with type 3 bacteria, and was correlated with the titer of elicited IgM and IgG3 anti-Cps14. These data show, for the first time, that exosomes can induce a humoral immune response to an associated unprocessed, autologous antigen. Although anti-Cps14 Ig responses are specifically demonstrated, these could reflect a broader mechanism that modulates both natural immunity and autoimmunity to other glycotopes.
AcpA Is aFrancisellaAcid Phosphatase That Affects Intramacrophage Survival and Virulence
Authors: Mohapatra Nrusingh P. , Balagopal Ashwin , Soni Shilpa , Schlesinger Larry S. , Gunn John S.
Published: December 2006

AcpA ofFrancisellaspp. is a respiratory-burst-inhibiting acid phosphatase that also exhibits phospholipase C activity. To better understand the molecular basis of AcpA in virulence, a deletion ofacpAwas constructed inFrancisella novicida. The phosphatase and lipase activities were reduced 10-fold and 8-fold, respectively, in theacpAmutant compared to the wild type and were found mostly associated with the outer membrane. TheacpAmutant was more susceptible to intracellular killing than the wild-type strain in the THP-1 human macrophage-like cell line. In addition, mice infected with theacpAmutant survived longer than the wild-type strain and were less fit than the wild-type strain in competition infection assays. Transmission electron microscopy showed that theacpAmutant was delayed in escape from macrophage phagosomes, as more than 75% ofacpAmutant bacteria could still be found inside phagosomes after 12 h of infection in THP-1 cells and human monocyte-derived macrophages, whereas most of the wild-type bacteria had escaped from the phagosome by 6 h postinfection. Thus, AcpA affects intracellular trafficking and the fate ofFrancisellawithin host macrophages.
Limited Role for CD4
+
T-Cell Help in the Initial Priming of
Trypanosoma cruzi-
Specific CD8
+
T Cells
Authors: Padilla Angel , Xu Dan , Martin Diana , Tarleton Rick
Published: December 2006

Immune control of the protozoan parasite
Trypanosoma cruzi
requires the activation of both CD4
+
and CD8
+
T cells. We recently identified two
T. cruzi trans
-sialidase peptides that are targets of approximately 30% of all CD8
+
T cells during acute
T. cruzi
infection in mice. To determine whether CD4
+
T cells are required for generation of these dominant CD8
+
T-cell responses, major histocompatibility complex class II (MHC II)-deficient mice were infected with the Brazil strain of
T. cruzi
and examined for the generation of antigen-specific CD8
+
T cells. Strong
trans
-sialidase TSKB18- and TSKB20-specific CD8
+
T-cell responses were generated in both the presence and the absence of CD4
+
help. However, the magnitudes of the immunodominant TSKB20-specific CD8
+
T-cell responses detectable using class I MHC-peptide tetramers were consistently lower in the blood and spleens of MHC II-deficient mice. Spleen cells from infected MHC II-deficient mice produced gamma interferon after in vitro stimulation with
T. cruzi
peptides at levels similar to those in wild-type mice, and MHC II-deficient mice displayed strong
T. cruzi
peptide-specific cytotoxic T-lymphocyte activity in vivo. Thus, primary CD8
+
T-cell responses in experimental
T. cruzi
infection are generated in the absence of CD4
+
T cells, providing further evidence that
T. cruzi
directly activates and licenses antigen-presenting cells. Nevertheless, unhelped CD8
+
T cells in
T. cruzi-
infected mice fail to reach the frequencies achieved in the presence of CD4 T-cell help and are unable to prevent acute-phase death of these mice.
Intranasal Inoculation of Mice withYersinia pseudotuberculosisCauses a Lethal Lung Infection That Is Dependent onYersiniaOuter Proteins andPhoP
Authors: Fisher Michael L. , Castillo Cynthia , Mecsas Joan
Published: December 2006

Yersinia pseudotuberculosisinfects many mammals and birds including humans, livestock, and wild rodents and can be recovered from the lungs of infected animals. To determine theY. pseudotuberculosisfactors important for growth during lung infection, we developed an intranasal model of infection in mice. Following intranasal inoculation, we monitored both bacterial growth in lungs and dissemination to systemic tissues. Intranasal inoculation with as few as 18 CFU ofY. pseudotuberculosiscaused a lethal lung infection in some mice. Over the course of 7 days, wild-typeY. pseudotuberculosisreplicated to nearly 1 × 108CFU/g of lung in BALB/c mice, induced histopathology in lungs consistent with pneumonia, but disseminated sporadically to other tissues. In contrast, a ΔyopBdeletion strain was attenuated in this model, indicating that translocation ofYersiniaouter proteins (Yops) is essential for virulence. Additionally, a ΔyopHnull mutant failed to grow to wild-type levels by 4 days postintranasal inoculation, but deletions of any other single effector YOP did not attenuate lung colonization 4 days postinfection. Strains with deletions inyopHand any one of the other known effectoryopgenes were more attenuated that the ΔyopHstrain, indicating a unique role foryopHin lungs. In summary, we have characterized the progression of a lung infection with an entericYersiniapathogen and shown that YopB and YopH are important in lung colonization and dissemination. Furthermore, this lung infection model withY. pseudotuberculosiscan be used to test potential therapeutics againstYersiniaand other gram-negative infections in lungs.
Role of Monocyte-Acquired Hemozoin in Suppression of Macrophage Migration Inhibitory Factor in Children with Severe Malarial Anemia
Authors: Awandare Gordon A. , Ouma Yamo , Ouma Collins , Were Tom , Otieno Richard , Keller Christopher C. , Davenport Gregory C. , Hittner James B. , Vulule John , Ferrell Robert , Ong'echa John M. , Perkins Douglas J.
Published: December 2006

Severe malarial anemia (SMA), caused byPlasmodium falciparuminfections, is one of the leading causes of childhood mortality in sub-Saharan Africa. Although the molecular determinants of SMA are largely undefined, dysregulation in host-derived inflammatory mediators influences disease severity. Macrophage migration inhibitory factor (MIF) is an important regulator of innate inflammatory responses that has recently been shown to suppress erythropoiesis and promote pathogenesis of SMA in murine models. To examine the role of MIF in the development of childhood SMA, peripheral blood MIF production was examined in Kenyan children (aged <3 years,n= 357) withP. falciparummalarial anemia. All children in the study were free from bacteremia and human immunodeficiency virus type 1. Since deposition of malarial pigment (hemozoin [Hz]) contributes to suppression of erythropoiesis, the relationship between MIF concentrations and monocytic acquisition of Hz was also examined in vivo and in vitro. Circulating MIF concentrations declined with increasing severity of anemia and significantly correlated with peripheral blood leukocyte MIF transcripts. However, MIF concentrations in peripheral blood were not significantly associated with reticulocyte production. Multivariate regression analyses, controlling for age, gender, and parasitemia, further revealed that elevated levels of pigment-containing monocytes (PCM) was associated with SMA and decreased MIF production. In addition, PCM levels were a better predictor of hemoglobin and MIF concentrations than parasite density. Additional experiments in malaria-naive individuals demonstrated that hemozoin caused both increased and decreased MIF production in cultured peripheral blood mononuclear cells (PBMC) in a donor-specific manner, independent of apoptosis. However, PBMC MIF production in children with acute malaria progressively declined with increasing anemia severity. Results presented here demonstrate that acquisition of hemozoin by monocytes is associated with suppression of peripheral blood MIF production and enhanced severity of anemia in childhood malaria.
TheMoraxella catarrhalisAutotransporter McaP Is a Conserved Surface Protein That Mediates Adherence to Human Epithelial Cells through Its N-Terminal Passenger Domain
Authors: Lipski Serena L. , Akimana Christine , Timpe Jennifer M. , Wooten R. Mark , Lafontaine Eric R.
Published: December 2006

The protein McaP was previously shown to be an adhesin expressed by theMoraxella catarrhalisstrain O35E, which also displays esterase and phospholipase B activities (J. M. Timpe et al., Infect. Immun. 71:4341-4350, 2003). In the present study, sequence analysis suggests that McaP is a conventional autotransporter protein that contains a 12-stranded β-barrel transporter module (amino acids [aa] 383 to 650) linked to a surface-exposed passenger domain exhibiting lipolytic activity (aa 62 to 330). An in-frame deletion removing most of this predicted N-terminal passenger domain was engineered, andEscherichia coliexpressing the truncated McaP protein exhibited greatly reduced adherence to A549 human lung epithelial cells compared toE. coliexpressing wild-type McaP. Site-directed mutagenesis of a serine residue at position 62 of McaP, predicted to be important for the lipolytic activity of the protein, resulted in loss of hydrolysis ofp-nitrophenyl ester of caproate.E. coliexpressing this mutated McaP, however, adhered to A549 monolayers at levels greater than recombinant bacteria expressing the wild-type adhesin. These results indicate that the predicted passenger domain of McaP is involved in both the binding and the lipolytic activity of the molecule and demonstrate that the adhesive properties of McaP do not require its lipolytic activity. Sequence analysis ofmcaPfrom eightMoraxella catarrhalisstrains revealed that the gene product is highly conserved at the amino acid level (98 to 100% identity), and Western blot analysis demonstrated that a panel of 16 isolates all express McaP. Flow cytometry experiments using antibodies raised against various portions of McaP indicated that its predicted passenger domain as well as transporter module contain surface-exposed epitopes. In addition to binding to the surface of intact bacteria, these antibodies were found to decrease adherence ofM. catarrhalisto A549 human lung cells by up to 47% and to reduce binding of recombinantE. coliexpressing McaP by 98%. These results suggest that McaP should be considered as a potential vaccine antigen.
Protein P200 Is Dispensable for
Mycoplasma pneumoniae
Hemadsorption but Not Gliding Motility or Colonization of Differentiated Bronchial Epithelium
Authors: Jordan Jarrat L. , Chang How-Yi , Balish Mitchell F. , Holt Lynley S. , Bose Stephanie R. , Hasselbring Benjamin M. , Waldo Robert H. , Krunkosky Thomas M. , Krause Duncan C.
Published: December 2006

Mycoplasma pneumoniae
protein P200 was localized to the terminal organelle, which functions in cytadherence and gliding motility. The loss of P200 had no impact on binding to erythrocytes and A549 cells but resulted in impaired gliding motility and colonization of differentiated bronchial epithelium. Thus, gliding may be necessary to overcome mucociliary clearance.
Long-Term Staphylococcal Enterotoxin C1 Exposure Induces Soluble Factor-Mediated Immunosuppression by Bovine CD4+and CD8+T Cells
Authors: Seo Keun Seok , Lee Sang Un , Park Yong Ho , Davis William C. , Fox Lawrence K. , Bohach Gregory A.
Published: December 2006

Regulatory T cells (Tregs) help control the development and maintenance of protective immunity and can lead to aberrant immune responses to some pathogens. Several lines of evidence suggest that Tregsare induced by exposure to superantigens (SAgs) in vitro or in vivo. In this study, bovine peripheral blood mononuclear cells (PBMC) were exposed in vitro to a relatively low dose (5 ng/ml) of staphylococcal enterotoxin C1 (SEC1) for up to 10 days. Upon stimulation, CD4+and CD8+T cells initially proliferated at similar rates. Subsequently, from days 6 through 10, most CD4+and CD8+T cells proliferated regardless of Vβ specificity, but the proliferation of CD8+T cells occurred more vigorously. The transcription of CD25 and CD152 genes increased, whereas that of interleukin-2 (IL-2) decreased. γδ T cells appeared to be unresponsive. An increase in the transcription of IL-10 and transforming growth factor β (TGF-β) genes in SEC1-stimulated cultures was attributed to the CD4+CD25+T-cell subpopulation. The expression of Foxp3 mRNA also increased and was accompanied by the upregulation of CD152 and the downregulation of IL-2 transcription, suggesting that cells in this subpopulation are Tregs. Functionally, SEC1-stimulated CD4+T cells suppressed the proliferation of naive PBMC in response to heat-killed-fixedStaphylococcus aureus. The suppression was partially mediated by IL-10 and TGF-β, another characteristic of certain types of Tregs.The CD8+T-cell population also suppressed naive PBMC through another mechanism not mediated by IL-10 or TGF-β. These results provide further insight into the potential mechanisms by which SAgs could contribute to evasion of the immune response, affecting the outcome of infection or colonization.
p38 Mitogen-Activated Protein Kinase Controls NF-κB Transcriptional Activation and Tumor Necrosis Factor Alpha Production through RelA Phosphorylation Mediated by Mitogen- and Stress-Activated Protein Kinase 1 in Response toBorrelia burgdorferiAntigens
Authors: Olson Chris M. , Hedrick Michael N. , Izadi Hooman , Bates Tonya C. , Olivera Elias R. , Anguita Juan
Published: December 2006

The interaction ofBorrelia burgdorferi, the causative agent of Lyme borreliosis, with phagocytic cells induces the activation of NF-κB and the expression of proinflammatory cytokines including tumor necrosis factor alpha (TNF-α).B. burgdorferi-induced TNF-α production is also dependent on the activation of p38 mitogen-activated protein (MAP) kinase. The specific contribution of these signaling pathways to the response of phagocytic cells to the spirochete and the molecular mechanisms underlying this response remain unresolved. We now show that p38 MAP kinase activity regulates the transcriptional activation of NF-κB in response to spirochetal lysate stimulation of phagocytic cells. The regulation occurs at the nuclear level and is independent of the translocation of the transcription factor to the nucleus or its capacity to bind to specific DNA target sequences. In RAW264.7 cells, p38α MAP kinase regulates the phosphorylation of NF-κB RelA. p38 MAP kinase phosphorylates the nuclear kinase mitogen- and stress-activated protein kinase 1 (MSK1). MSK1 in turn phosphorylates the transcriptionally active subunit of NF-κB, RelA. The repression of MSK1 expression with small interfering RNA results in reduced RelA phosphorylation and a significant decrease in the production of TNF-α in response toB. burgdorferilysates. Overall, these results clarify the contribution of the signaling pathways that are activated in response to the interaction of spirochetes with phagocytic cells to TNF-α production. Our results situate p38 MAP kinase activity as a central regulator of the phagocytic proinflammatory response through MSK1-mediated transcriptional activation of the transcription factor NF-κB.
Role of the
wbt
Locus of
Francisella tularensis
in Lipopolysaccharide O-Antigen Biogenesis and Pathogenicity
Authors: Raynaud Catherine , Meibom Karin L. , Lety Marie-Annick , Dubail Iharilalao , Candela Thomas , Frapy Eric , Charbit Alain
Published: December 2006

Francisella tularensis
is a highly infectious bacterial pathogen, responsible for the zoonotic disease tularemia. We screened a bank of transposon insertion mutants of
F. tularensis
subsp.
holarctica
LVS for colony morphology alterations and selected a mutant with a transposon insertion in
wbtA
, the first gene of the predicted lipopolysaccharide O-antigen gene cluster. Inactivation of
wbtA
led to the complete loss of O antigen, conferred serum sensitivity, impaired intracellular replication, and severely attenuated virulence in the mouse model. Notably, this mutant afforded protection against a challenge against virulent LVS.
The
blp
Bacteriocins of
Streptococcus pneumoniae
Mediate Intraspecies Competition both In Vitro and In Vivo
Authors: Dawid Suzanne , Roche Aoife M. , Weiser Jeffrey N.
Published: December 2006

The introduction of the conjugate seven-valent pneumococcal vaccine has led to the replacement of vaccine serotypes with nonvaccine serotypes of
Streptococcus pneumoniae
. This observation implies that intraspecies competition between pneumococci occurs during nasopharyngeal colonization, allowing one strain or set of strains to predominate over others. We investigated the contribution of the
blp
locus, encoding putative bacteriocins and cognate immunity peptides, to intraspecies competition. We sequenced the relevant regions of the
blp
locus of a type 6A strain able to inhibit the growth of the type 4 strain, TIGR4, in vitro. Using deletional analysis, we confirmed that inhibitory activity is regulated by the function of the response regulator, BlpR, and requires the two putative bacteriocin genes
blpM
and
blpN
. Comparison of the TIGR4 BlpM and -N amino acid sequences demonstrated that only five amino acid differences were sufficient to target the heterologous strain. Analysis of a number of clinical isolates suggested that the BlpMN bacteriocins divide into two families. A mutant in the
blpMN
operon created in the clinically relevant type 19A background was deficient in both bacteriocin activity and immunity. This strain was unable to compete with both its parent strain and a serotype 4 isolate during cocolonization in the mouse nasopharynx, suggesting that the locus is functional in vivo and confirming its role in promoting intraspecies competition.
DEVELOPMENT OF AN IN-AIR ON/OFF AXIS STIM SYSTEM FOR QUANTITATIVE ELEMENTAL MAPPING
Authors: INOMATA K. , ISHII K. , YAMAZAKI H. , MATSUYAMA S. , KIKUCHI Y. , WATANABE Y. , ISHIZAKI A. , OYAMA R. , KAWAMURA Y. , YAMAGUCHI T. , MOMOSE G. , SAKURAI E. , YANAI K. , KAMIYA T. , SAKAI T. , SATOH T. , OIKAWA M. , ARAKAWA K.
Published: December 2006

We have developed an in-air on/off axis STIM for simultaneous density mapping with PIXE and RBS, which will be useful for damage-monitoring in cell analysis and for yield correction based on the thickness distribution of X-ray self-absorption in samples. The in-air on/off axis STIM system provides a mass concentration map in the cell analysis. In the system, a thin scattering foil is placed downstream of the sample and scattered protons are detected by a Si -PIN photodiode set at 30 degrees with respect to the beam axis. These components are set in a He -gas-filled chamber to reduce energy loss, scattering and sample damage. Using this system, areal density mapping is carried out for RBL-2H3 cells simultaneously with PIXE and RBS. Correction for self-absorption is performed and areal density map of elements is converted into a mass-concentration map using the measured matrix density. The areal density distribution of P corresponds to that of matrix and mass concentration of P is uniform in the cell region. On the other hand, Br is concentrated in the nucleus, even in the mass concentration map. The Br accumulation in the nucleus is first confirmed in mass concentration using the on/off axis STIM and PIXE system. The in-air on/off STIM system will be effective for monitoring changes in cell density during beam irradiation.
APPLICATION OF A POWDERED-INTERNAL-STANDARD METHOD TO POWDERED HAIR SAMPLES PREPARED BY A NEW METHOD
Authors: SAITOH Y. , ITOH J. , SAKURAI S. , FUTATSUGAWA S. , SERA K.
Published: December 2006

PIXE analysis has been performed at NMCC (Nishina Memorial Cyclotron Center) as a common utilization in Japan since 1993. In order to cope with a variety of samples, various sample-preparation methods have been developed at NMCC. In order to make uniform hair samples of large quantity, a method of powdering in liquid nitrogen was carried out. A powdered-internal-standard method was applied to the powdered hair sample thus prepared and the results were compared with those obtained by a standard- free method for untreated hairs and with those by an internal-standard method combined with the chemical ashing method. As a result, good agreement was obtained for the principal elements such as sulfur, calcium and zinc. Moreover, good reproducibility was achieved in the results obtained by repeated measurements, and it is found that uniformity of the powdered sample and the powdered- internal standard (palladium-carbon) was almost satisfactory.
CONSTRUCTING DIMENSION-ADAPTIVE SPARSE GRID INTERPOLANTS USING PARALLEL FUNCTION EVALUATIONS
Authors: KLIMKE ANDREAS , WOHLMUTH BARBARA
Published: December 2006

Dimension-adaptive sparse grid interpolation is a powerful tool to obtain surrogate functions of smooth, medium to high-dimensional objective models. In case of expensive models, the efficiency of the sparse grid algorithm is governed by the time required for the function evaluations. In this paper, we first briefly analyze the inherent parallelism of the standard dimension-adaptive algorithm. Then, we present an enhanced version of the standard algorithm that permits, in each step of the algorithm, a specified number (equal to the number of desired processes) of function evaluations to be executed in parallel, thereby increasing the parallel efficiency.
SHARING MEMORY WITH SEMI-BYZANTINE CLIENTS AND FAULTY STORAGE SERVERS
Authors: ATTIYA HAGIT , BAR-OR AMIR
Published: December 2006

This paper presents fault-tolerant simulations of a single-writer multi-reader regular register in storage systems. One simulation tolerates fail-stop failures of storage servers and requires a majority of nonfaulty servers, while the other simulation tolerates Byzantine failures and assumes that two-thirds of the servers are nonfaulty. A construction of Afek et al. [3] is used to mask semi-Byzantine failures of clients that result in erroneous write operations. The simulations are used to derive Paxos algorithms that tolerate semi-Byzantine failures of clients as well as fail-stop or Byzantine failures of storage servers.
PARALLELIZING AN APPLICATION WITH TIME-INCREASING WORKLOAD USING ADAPTIVE PROCESSOR ALLOCATION
Authors: HUANG KUO-CHAN , WANG FENG-JIAN
Published: December 2006

This paper presents our experience in parallelizing a Monte Carlo/fluid hybrid simulation of radio frequency glow discharge in plasma physics. The application is a dynamic loosely-synchronous system with time-increasing workload. We adopt adaptive processor allocation to effectively parallelize the time-increasing workload. The results show that adaptive processor allocation has potential to improve performance of parallel applications with time-varying workloads. The methods proposed in this paper can be applied to other dynamic loosely-synchronous applications as well.
A HIGHLY CONCURRENT GROUP MUTUAL l-EXCLUSION ALGORITHM
Authors: VIDYASANKAR K.
Published: December 2006

The asynchronous group mutual exclusion (GME) problem [5] is a generalization of the (ordinary) mutual exclusion problem. Each process requests a forum. When a process is in the critical section (CS), we say its forum is held. The GME problem (i) allows at most one forum to be held at any time and, (ii) when a forum is held, encourages any number of processes requesting that forum to participate in that forum, that is, to be in the CS simultaneously. An extension of this problem, called the group mutual l-exclusion with multiple forum requests (GMLE-M) problem [8], allows each process to request multiple forums and up to l forums to be held simultaneously. In this paper, we give a simple GMLE-M algorithm that facilitates a highly concurrent participation of processes in forums. The algorithm uses a new technique, called automatic joining, that enables processes to enter the CS directly when their forums are being held. This technique can be used in other extensions of the GME problem also, to increase concurrency.
THE OPERATIONS DASHBOARD: A COLLABORATIVE ENVIRONMENT FOR MONITORING VIRTUAL ORGANIZATION-SPECIFIC COMPUTE ELEMENT OPERATIONAL STATUS
Authors: RUBY CATHERINE L. , GREEN MARK L. , MILLER RUSS
Published: December 2006

Grid computing integrates heterogeneous, geographically distributed, Internet-ready resources that are administered under multiple domains. A key challenge in grid computing is to provide a high quality of service to users in a transparent fashion, hiding issues that include ownership, administration, and geographic location of a wide variety of resources that provide compute cycles, data storage, rendering cycles, imaging devices, and sensors, to name a few. Ensuring the functionality of a wide variety of resources under multiple administrative policies requires tools for discovering, repairing, and publishing information on the services offered by individual sites within a given grid. In this paper, we present the ACDC Operations Dashboard, an interactive, collaborative environment for collecting, addressing, and publishing operational service information for resources across a computational grid.
THE ASSOCIATED PRODUCTION OF THE NEUTRAL TOP-PION WITH A PAIR OF THIRD FAMILY QUARKS AT THE HADRON COLLIDERS
Authors: WANG XUELEI , YU LILI , SONG NAHONG , XU WENNA
Published: December 2006

We study the associated production of the neutral top-pion [Formula: see text] with the third family quarks within the context of the topcolor-assisted technicolor model at the hadron colliders. The studies show that, at the Tevatron, the cross-sections of all these processes are too small to produce enough identified signals. But the cross-sections can be largely enhanced at the LHC. Specially for the processes [Formula: see text] and [Formula: see text], the cross-sections can reach the level of a few hundred fb even a few pb for the light neutral top-pion. With the high yearly luminosity 100 fb-1 at the LHC, over 104 signals can be produced via the above two processes. There exists an ideal flavor-changing mode to detect neutral top-pion, i.e. [Formula: see text], because the SM background of such production mode are very clean. Therefore, we can conclude that neutral top-pion should be observable at the LHC via the processes [Formula: see text] and [Formula: see text]. On the other hand, the statistics available at the LHC via these two processes might be enough to measure the Yukawa couplings [Formula: see text] and [Formula: see text]. Finally, it must be noted that the study of the process [Formula: see text] can give us a good chance to distinguish the TC2 model from the SM and MSSM because there does not exist such similar tree-level favor-changing process in these models.
ON SOME PROPERTIES OF THE VACUUM ENERGY OF THE UNIVERSE
Authors: BHATTACHARYA A. , BANERJEE S. N. , CHAKRABARTI B. , BANERJEE S. , MANI S.
Published: December 2006

The contribution of the cosmological constant to the ground state energy of the quantum vacuum field has been investigated in the framework of the Casimir energy calculation. A regularization scheme is suggested. The equation of state and the nature of the corresponding medium has been studied with some interesting observations.
THE HATSOPOULOS–GYFTOPOULOS RESOLUTION OF THE SCHRÖDINGER–PARK PARADOX ABOUT THE CONCEPT OF "STATE" IN QUANTUM STATISTICAL MECHANICS
Authors: BERETTA GIAN PAOLO
Published: December 2006

A seldom recognized fundamental difficulty undermines the concept of individual "state" in the present formulations of quantum statistical mechanics (and in its quantum information theory interpretation as well). The difficulty is an unavoidable consequence of an almost forgotten corollary proved by Schrödinger in 1936 and perused by Park, Am. J. Phys.36, 211 (1968). To resolve it, we must either reject as unsound the concept of state, or else undertake a serious reformulation of quantum theory and the role of statistics. We restate the difficulty and discuss a possible resolution proposed in 1976 by Hatsopoulos and Gyftopoulos, Found. Phys.6, 15; 127; 439; 561 (1976).
QCD EFFECTIVE ACTION WITH A MOST GENERAL HOMOGENEOUS FIELD BACKGROUND
Authors: CHO Y. M. , KIM J. H. , PAK D. G.
Published: December 2006

We consider one-loop effective action of SU(3) QCD with a most general constant chromomagnetic (chromoelectric) background which has two independent Abelian field components. The effective potential with a pure magnetic background has a local minimum only when two Abelian components [Formula: see text] and [Formula: see text] of color magnetic field are orthogonal to each other. The nontrivial structure of the effective action has important implication in estimating quark–gluon production rate and pT-distribution in quark–gluon plasma. In general the production rate depends on three independent Casimir invariants, in particular, it depends on the relative orientation between chromoelectric fields.
CHIRALITY OF ALTERNATING KNOTS IN S × I
Authors: FLEMING THOMAS
Published: December 2006

In this paper, we will explore the properties of knots that lie in a surface cross an interval. We show that any alternating knot nontrivially embedded in S × I is chiral. This demonstrates that knots in S × I behave differently from knots in the three sphere, where alternating knots (like the figure eight) can be amphichiral. We use a generalized Kauffman bracket polynomial, as well as geometric and covering space techniques.
GRAPHS WITH A KNOT OR 3-COMPONENT LINK IN EVERY SPATIAL EMBEDDING
Authors: FOISY JOEL
Published: December 2006

We describe a family of graphs that contain a knot or a non-split 3-component link in every spatial embedding. We exhibit a graph in this family that has a knotless embedding, and a 3-component linkless embedding.
ANY TANGLE EXTENDS TO NON-MUTANT KNOTS WITH THE SAME JONES POLYNOMIAL
Authors: WATSON LIAM
Published: December 2006

We show that an arbitrary tangle T can be extended to produce diagrams of two distinct knots that cannot be distinguished by the Jones polynomial. When T is a prime tangle, the resulting knots are prime. It is also shown that, in either case, the resulting pair are not mutants.
THE ALEXANDER POLYNOMIAL OF (1,1)-KNOTS
Authors: CATTABRIGA A.
Published: December 2006

In this paper we investigate the Alexander polynomial of (1,1)-knots, which are knots lying in a 3-manifold with genus one at most, admitting a particular decomposition. More precisely, we study the connections between the Alexander polynomial and a polynomial associated to a cyclic presentation of the fundamental group of an n-fold strongly-cyclic covering branched over the knot K, which we call the n-cyclic polynomial of K. In this way, we generalize to all (1,1)-knots, with the only exception of those lying in S2×S1, a result obtained by Minkus for 2-bridge knots and extended by the author and M. Mulazzani to the case of (1,1)-knots in S3. As corollaries some properties of the Alexander polynomial of knots in S3are extended to the case of (1,1)-knots in lens spaces.
CONVEX BRUNNIAN LINKS
Authors: HOWARDS HUGH NELSON
Published: December 2006

We prove that the Borromean Rings are the only Brunnian link of 3 or 4 components that can be built out of convex curves.
VASSILIEV INVARIANTS AND SIMILARITY INDICES OF KNOTS, LINKS AND TANGLES
Authors: JEONG MYEONG-JU , PARK CHAN-YOUNG
Published: December 2006

Whether Vassiliev invariants can distinguish all knots or not is a well-known open problem which is equivalent to the question whether the similarity index of any two different knots is finite or not. We give relations between the degrees of Vassiliev invariants and the similarity indices of knots, links and tangles. From these, we get necessary conditions for a knot invariant to be a Vassiliev invariant and get methods to detect the similarity index of two knots or tangles.
AUTOMORPHISMS OF BRAID GROUPS ON CLOSED SURFACES WHICH ARE NOT S2, T2, P2 OR THE KLEIN BOTTLE
Authors: ZHANG PING
Published: December 2006

Consider a surface braid group of n strings as a subgroup of the isotopy group of homeomorphisms of the surface permuting n fixed distinguished points. Each automorphism of the surface braid group (respectively, of the special surface braid group) is shown to be a conjugate action on the braid group (respectively, on the special braid group) induced by a homeomorphism of the underlying surface if the closed surface, either orientable or non-orientable, is of negative Euler characteristic. In other words, the group of automorphisms of such a surface braid group is isomorphic to the extended mapping class group of the surface with n punctures, while the outer automorphism group of the surface braid group is isomorphic to the extended mapping class group of the closed surface itself.
LOCAL MOVES AND GORDIAN COMPLEXES
Authors: NAKANISHI YASUTAKA , OHYAMA YOSHIYUKI
Published: December 2006

By the works of Gusarov [2] and Habiro [3], it is known that a local move called the Cnmove is strongly related to Vassiliev invariants of order less than n. The coefficient of the znterm in the Conway polynomial is known to be a Vassiliev invariant of order n. In this note, we will consider to what degree the relationship is strong with respect to Conway polynomial. Let K be a knot, and KCnthe set of knots obtained from a knot K by a single Cnmove. Let [Formula: see text] be the set of the Conway polynomials [Formula: see text] for a set of knots [Formula: see text]. Our main result is the following: There exists a pair of knots K1, K2such that ∇K1= ∇K2and [Formula: see text]. In other words, the CnGordian complex is not homogeneous with respect to Conway polynomial.
BOUNDING DISKS TO A SPATIAL GRAPH
Authors: SHINJO REIKO
Published: December 2006

We consider Seifert surfaces of knots in a spatial graph whose interiors are mutually disjoint. We give the upper bound of the number of such surfaces. Then we show that for a given abstract graph there is a spatial embedding of the graph which realizes the upper bound.
LINEAR FIRST-ORDER FUZZY DIFFERENTIAL EQUATIONS
Authors: NIETO JUAN J. , RODRÍGUEZ-LÓPEZ ROSANA , FRANCO DANIEL
Published: December 2006

We give the expression for the solution to some particular initial value problems in the space E1 of fuzzy subsets of ℝ. We deduce some interesting properties of the diameter and the midpoint of the solution and compare the solutions with the corresponding ones in the crisp case.
AUTOMORPHISMS OF THE ALGEBRA OF FUZZY TRUTH VALUES
Authors: WALKER CAROL L. , WALKER ELBERT A.
Published: December 2006

This paper is an investigation of the automorphisms of the algebra of truth values of type-2 fuzzy sets. This algebra contains isomorphic copies of the truth value algebras of type-1 and of interval-valued fuzzy sets. It is shown that these subalgebras are characteristic; that is, are carried onto themselves by automorphisms of the containing algebra of truth values of fuzzy sets. Some other relevant subalgebras are proved characteristic, including the subalgebra of convex normal functions. The principal tool in this study is the determination of various irreducible elements.
A NOTE ON FAIR DIVISION UNDER INTERVAL UNCERTAINTY
Authors: WOEGINGER GERHARD J.
Published: December 2006

In a recent paper [International Journal of Uncertainty, Fuzziness, and Knowledge-Based Systems 8:611–618], Yager & Kreinovich characterize a certain proportional division rule in terms of the three axioms (1) symmetry, (2) participant mergability, and (3) continuity. This technical note tightens their characterization: The proportional division rule is already fully characterized by the first two axioms (1) symmetry and (2) participant mergability.
INTERVAL METHODS IN KNOWLEDGE REPRESENTATION
Authors: Kreinovich Vladik
Published: December 2006

This section is maintained by Vladik Kreinovich. Please send your abstracts (or copies of papers that you want to see reviewed here) to vladik@utep.edu, or by regular mail to: V. Kreinovich, Department of Computer Science, University of Texas, El Paso, TX 79968, USA.
PROSPECTS FOR A MOLECULAR SUPERCOMPUTER 15 YEARS AHEAD
Authors: WADA YASUO
Published: December 2006

Current information technologies totally rely on semiconductor devices and magnetic/optical discs, however, they are all foreseen to face fundamental limitations within a decade. Therefore, superseding devices are required for the next paradigm of high performance information technologies. This paper describes prospects for a molecular supercomputer which would be the only possible candidate beyond the silicon limitations. Possible four milestones for realizing the Peta/Exa-floating operations per second (FLOPS) personal molecular supercomputer are proposed. Current status and necessary technologies of the first milestone are described, and necessary technologies for the next three milestones are also discussed.
SUB-100 nm LITHOGRAPHY WITH PATTERN AND PARTIAL COHERENCE CONTROL
Authors: TEO SELIN H. G. , LIU A. Q. , SINGH J. , YU M. B. , SUN H. Q. , SINGH N.
Published: December 2006

This paper describes optical patterning of sub-lithographic wavelength features using only conventional chrome-on-glass binary photomasks without phase-shift features. The sub-100 nm patterns were obtained through manipulation of masks bias designs and partial coherence control of the lithographic radiation. The key factors in the design of experiments are the density and design of masks patterns and the partial coherence of exposure radiation system used. Based on the study, smallest resolution of 36% that of designed value can be obtained for features of 75 nm using a 200 nm designed line width. Besides indication of proposed process' resolution limits for further applications, advantages of the method allows its application to applications requiring sub-100 nm critical dimensions through use of biased pattern designs, especially feasible in devices such as deep sub-micrometer comb drives actuators in nano-microelectromechanical structures; metal–semiconductor–metal photodetectors, and nanophotonic crystal structures, etc.
IMPEDANCE ANALYSIS FOR CHARACTERIZATION OF MATERIALS USED IN ORGANIC TRANSISTORS
Authors: LI CHANG MING , PAN LIKUN , GAN YE , SUN CHAN QING , ZHANG JIE , GAMOTA DAN
Published: December 2006

A method of impedance frequency response analysis (FRA) with template multilayer organic capacitor was studied to evaluate printable materials for all-printed organic field-effect transistors (OFETs). The new method allows us not only to characterize simultaneously dielectric and conductive behaviors of the materials but also to distinguish contributions to electrical conduction or to polarization from different sources such as dielectric layer, semiconductor layer, and different interfaces for OFETs. As a dielectric layer for OFETs, Urathan is preferred because of lower conductivity, nonmetallic conduction behavior at high temperature, and lower interfacial resistance. Conductivity and dielectric enhancement of Urathan can be realized by heating. The critical temperature for conductivity and dielectricity transition was calculated from FRA from temperature dependent experiments. The method could be a standard for fast screening and assessing printable materials for OFETs.
ANNEALING EFFECTS ON ELECTRIC CONTACTS BETWEEN CARBON NANOTUBES AND ELECTRODES
Authors: LI JINGQI , ZHANG QING , CHAN-PARK MARY B. , YAN YEHAI
Published: December 2006

Single wall carbon nanotubes suspended in isopropyl alcohol are placed between two Au electrodes by ac dielectrophoresis method. Total resistance including the contact resistance and intrinsic tube resistance is found to decrease from 105–106 Ω for as-prepared samples to 104 Ω after annealing at 300°C in ambient environment. Measured I–V curves and Schottky barrier heights suggest that the electric contacts are changed from Schottky to Ohmic characteristics after annealing. These results demonstrate that annealing in ambient environment is a simple and efficient way to decrease the contact resistance.