bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical inverse method predicting acoustic spinning modes radiated by a ducted fan from free-field test data
Authors: Lewy Serge
Published: July 2008

Spinning modes generated by a ducted turbofan at a given frequency determine the acoustic free-field directivity. An inverse method starting from measured directivity patterns is interesting in providing information on the noise sources without requiring tedious spinning-mode experimental analyses. According to a previous article, equations are based on analytical modal splitting inside a cylindrical duct and on a Rayleigh or a Kirchhoff integral on the duct exit cross section to get far-field directivity. Equations are equal in number to free-field measurement locations and the unknowns are the propagating mode amplitudes (there are generally more unknowns than equations). A MATLAB procedure has been implemented by using either the pseudoinverse function or the backslash operator. A constraint comes from the fact that squared modal amplitudes must be positive which involves an iterative least squares fitting. Numerical simulations are discussed along with several examples based on tests performed by Rolls–Royce in the framework of a European project. It is assessed that computation is very fast and it well fits the measured directivities, but the solution depends on the method and is not unique. This means that the initial set of modes should be chosen according to any known physical property of the acoustic sources.
Using streamlines to visualize acoustic energy flow across boundaries
Authors: Chapman David M. F.
Published: July 2008

For spherical waves that radiate from a point source in a homogeneous fluid and propagate across a plane boundary into a dissimilar homogeneous fluid, the acoustic field may differ significantly from the geometric acoustic approximation if either the source or receiver is near the interface (in acoustic wavelengths) or if the stationary phase path is near the critical angle. In such cases, the entire acoustic field must be considered, including inhomogeneous waves associated with diffraction (i.e., those components that vanish with increasing frequency). The energy flow from a continuous-wave monopole point source across the boundary is visualized by tracing acoustic streamlines: those curves whose tangent at every point is parallel to the local acoustic intensity vector, averaged over a wave cycle. It is seen that the acoustic energy flow is not always in line with the “Snell’s law” or stationary phase path. Also, plots of acoustic energy streamlines do not display unusual behavior in the vicinity of the critical angle. Finally, it is shown that there exists a law of refraction of acoustic energy streamlines at boundaries with density discontinuities analogous to Snell’s law of refraction of ray paths across sound speed discontinuities. Examples include water-to-seabed transmission and water-to-air transmission.
Perceptually motivated wavelet packet transform for bioacoustic signal enhancement
Authors: Ren Yao , Johnson Michael T. , Tao Jidong
Published: July 2008

A significant and often unavoidable problem in bioacoustic signal processing is the presence of background noise due to an adverse recording environment. This paper proposes a new bioacoustic signal enhancement technique which can be used on a wide range of species. The technique is based on a perceptually scaled wavelet packet decomposition using a species-specific Greenwood scale function. Spectral estimation techniques, similar to those used for human speech enhancement, are used for estimation of clean signal wavelet coefficients under an additive noise model. The new approach is compared to several other techniques, including basic bandpass filtering as well as classical speech enhancement methods such as spectral subtraction, Wiener filtering, and Ephraim–Malah filtering. Vocalizations recorded from several species are used for evaluation, including the ortolan bunting (Emberiza hortulana), rhesus monkey (Macaca mulatta), and humpback whale (Megaptera novaeanglia), with both additive white Gaussian noise and environment recording noise added across a range of signal-to-noise ratios (SNRs). Results, measured by both SNR and segmental SNR of the enhanced wave forms, indicate that the proposed method outperforms other approaches for a wide range of noise conditions.
High-Resolution Scanning X-ray Diffraction Microscopy
Authors: Thibault Pierre , Dierolf Martin , Menzel Andreas , Bunk Oliver , David Christian , Pfeiffer Franz
Published: July 2008

Coherent diffractive imaging (CDI) and scanning transmission x-ray microscopy (STXM) are two popular microscopy techniques that have evolved quite independently. CDI promises to reach resolutions below 10 nanometers, but the reconstruction procedures put stringent requirements on data quality and sample preparation. In contrast, STXM features straightforward data analysis, but its resolution is limited by the spot size on the specimen. We demonstrate a ptychographic imaging method that bridges the gap between CDI and STXM by measuring complete diffraction patterns at each point of a STXM scan. The high penetration power of x-rays in combination with the high spatial resolution will allow investigation of a wide range of complex mesoscopic life and material science specimens, such as embedded semiconductor devices or cellular networks.
Response to Comment on "A 3-Hydroxypropionate/4-Hydroxybutyrate Autotrophic Carbon Dioxide Assimilation Pathway in Archaea"
Authors: Berg Ivan A. , Kockelkorn Daniel , Buckel Wolfgang , Fuchs Georg
Published: July 2008

We proposed that the 3-hydroxypropionate/4-hydroxybutyrate cycle might be important in global carbon cycling based on the abundance of related autotrophic Crenarchaea in the ocean and the high number of gene sequences for a key enzyme of the cycle. Here, we counter the specific criticisms raised by Ettema and Andersson.
Antibiotics and Antibiotic Resistance Genes in Natural Environments
Authors: Martínez José L.
Published: July 2008

The large majority of antibiotics currently used for treating infections and the antibiotic resistance genes acquired by human pathogens each have an environmental origin. Recent work indicates that the function of these elements in their environmental reservoirs may be very distinct from the “weapon-shield” role they play in clinical settings. Changes in natural ecosystems, including the release of large amounts of antimicrobials, might alter the population dynamics of microorganisms, including selection of resistance, with consequences for human health that are difficult to predict.
Riboswitches in Eubacteria Sense the Second Messenger Cyclic Di-GMP
Authors: Sudarsan N. , Lee E. R. , Weinberg Z. , Moy R. H. , Kim J. N. , Link K. H. , Breaker R. R.
Published: July 2008

Cyclic di-guanosine monophosphate (di-GMP) is a circular RNA dinucleotide that functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes, including cell differentiation, conversion between motile and biofilm lifestyles, and virulence gene expression. However, the mechanisms by which cyclic di-GMP regulates gene expression have remained a mystery. We found that cyclic di-GMP in many bacterial species is sensed by a riboswitch class in messenger RNA that controls the expression of genes involved in numerous fundamental cellular processes. A variety of cyclic di-GMP regulons are revealed, including some riboswitches associated with virulence gene expression, pilus formation, and flagellum biosynthesis. In addition, sequences matching the consensus for cyclic di-GMP riboswitches are present in the genome of a bacteriophage.
Genetic and Structural Insights into the Dissemination Potential of the Extremely Broad-Spectrum Class A β-Lactamase KPC-2 Identified in an
Escherichia coli
Strain and an
Enterobacter cloacae
Strain Isolated from the Same Patient in France
Authors: Petrella Stephanie , Ziental-Gelus Nathalie , Mayer Claudine , Renard Murielle , Jarlier Vincent , Sougakoff Wladimir
Published: July 2008

Two clinical strains of
Escherichia coli
(2138) and
Enterobacter cloacae
(7506) isolated from the same patient in France and showing resistance to extended-spectrum cephalosporins and low susceptibility to imipenem were investigated. Both strains harbored the plasmid-contained
bla
TEM-1
and
bla
KPC-2
genes.
bla
KLUC-2
, encoding a mutant of the chromosomal β-lactamase of
Kluyvera cryocrescens
, was also identified at a plasmid location in
E. cloacae
7506, suggesting the IS
Ecp1
-assisted escape of
bla
KLUC
from the chromosome. Determination of the KPC-2 structure at 1.6 Å revealed that the binding site was occupied by the C-terminal (C-ter) residues coming from a symmetric KPC-2 monomer, with the ultimate C-ter Glu interacting with Ser130, Lys234, Thr235, and Thr237 in the active site. This mode of binding can be paralleled to the inhibition of the TEM-1 β-lactamase by the inhibitory protein BLIP. Determination of the 1.23-Å structure of a KPC-2 mutant in which the five C-ter residues were deleted revealed that the catalytic site was filled by a citrate molecule. Structure analysis and docking simulations with cefotaxime and imipenem provided further insights into the molecular basis of the extremely broad spectrum of KPC-2, which behaves as a cefotaximase with significant activity against carbapenems. In particular, residues 104, 105, 132, and 167 draw a binding cavity capable of accommodating both the aminothiazole moiety of cefotaxime and the 6α-hydroxyethyl group of imipenem, with the binding of the former drug being also favored by a significant degree of freedom at the level of the loop at positions 96 to 105 and by an enlargement of the binding site at the end of strand β3.
Mechanism of Action of the Antibiotic NXL101, a Novel Nonfluoroquinolone Inhibitor of Bacterial Type II Topoisomerases
Authors: Black Michael T. , Stachyra Thérèse , Platel Denis , Girard Anne-Marie , Claudon Monique , Bruneau Jean-Michel , Miossec Christine
Published: July 2008

NXL101 is one of a new class of quinoline antibacterial DNA gyrase and topoisomerase IV inhibitors showing potent activity against gram-positive bacteria, including methicillin- and fluoroquinolone-resistant strains. NXL101 inhibited topoisomerase IV more effectively than gyrase from
Escherichia coli
, whereas the converse is true of enzymes from
Staphylococcus aureus
. This apparent target preference is opposite to that which is associated with most fluoroquinolone antibiotics. In vitro isolation of
S. aureus
mutants resistant to NXL101 followed by cloning and sequencing of the genes encoding gyrase and topoisomerase IV led to the identification of several different point mutations within, or close to, the quinolone resistance-determining region (QRDR) of GyrA. However, the mutations were not those that are most frequently associated with decreased sensitivity to quinolones. A fluoroquinolone-resistant mutant variant of gyrase generated in vitro was highly resistant to inhibition by the fluoroquinolones ciprofloxacin and moxifloxacin but remained fully susceptible to inhibition by NXL101. Two mutant gyrases constructed in vitro, with mutations in
gyrA
engineered according to those most frequently found in
S. aureus
strains resistant to NXL101, were insensitive to inhibition by NXL101 and had a diminished sensitivity to ciprofloxacin and moxifloxacin. Certain combinations of mutations giving rise to NXL101 resistance and those giving rise to fluoroquinolone resistance may be mutually exclusive.
Recombination and Selection Can RemoveblaTEMAlleles from Bacterial Populations
Authors: Mroczkowska Joanna E. , Barlow Miriam
Published: July 2008

We passaged cells expressing TEM-1 and TEM-12 from a single plasmid through either ampicillin or ceftazidime. We found that the combined effects of recombination and selection removed theblaTEM-1allele from the bacterial population when it was passaged through ceftazidime or theblaTEM-12allele when cultures were passaged through ampicillin.
Evaluation of a Multiplex Flow Immunoassay for Detection of Epstein-Barr Virus-Specific Antibodies
Authors: Binnicker M. J. , Jespersen D. J. , Harring J. A. , Rollins L. O. , Beito E. M.
Published: July 2008

Conventional methods for the detection of Epstein-Barr virus (EBV)-specific antibodies include the immunofluorescence assay (IFA) and enzyme immunoassay (EIA). While sensitive and specific, these methods are labor-intensive and require separate assays for each analyte. This study evaluated the performance of a multiplex bead assay (BioPlex 2200; Bio-Rad Laboratories, Hercules, CA) for the simultaneous detection of immunoglobulin G (IgG) and IgM class antibodies to the EBV viral capsid antigen (VCA) and IgG class antibodies to Epstein-Barr virus nuclear antigen-1 (EBNA-1). Serum specimens (n= 1,315) submitted for routine EBV-specific antibody testing by EIA (Grifols-Quest, Inc., Miami, FL) were also tested by the multiplex bead assay using the BioPlex 2200 automated analyzer. Specimens showing discordant results were tested by IFA. Following IFA resolution, the BioPlex VCA IgM, VCA IgG, and EBNA-1 IgG assays demonstrated 97.9%, 91.4%, and 96.9% agreement, respectively, with the results obtained by EIA. Furthermore, the BioPlex assays showed an overall agreement of 94.1% with the EIA when the specimens were categorized by disease state (susceptible, acute, or past infection) based on the EBV-specific antibody profiles. These findings indicate that the BioPlex EBV assays demonstrate a performance comparable to that of the conventional EIA, while allowing for a more rapid (2.3 h for 100 samples versus 4.5 h by the EIA) and higher-throughput (∼400 samples per 9 h versus 200 samples by the EIA) analysis of the EBV-specific antibody response.
Vaccination with Heat Shock Protein 60 Induces a Protective Immune Response against ExperimentalParacoccidioides brasiliensisPulmonary Infection
Authors: de Bastos Ascenço Soares Renata , Gomez Francisco J. , de Almeida Soares Célia Maria , Deepe George S.
Published: July 2008

Paracoccidioides brasiliensiscauses a chronic granulomatous mycosis prevalent in Latin America. The successful resolution of infection with this fungus is dependent on the activation of cellular immunity. We previously identified heat shock protein 60 (HSP60) as a target of the humoral response in paracoccidioidomycosis. Herein we expressed the gene encoding HSP60 inEscherichia coliand analyzed the immunological activity of this recombinant antigen. The immunization of BALB/c mice with recombinant protein emulsified in adjuvant stimulated a cellular immune response. Splenocytes from immunized mice proliferated in response to antigen and released interleukin-12 and gamma interferon (IFN-γ). Vaccination with HSP60 reduced the fungal burden in mice given 106or 107yeasts and protected mice from a lethal challenge. The efficacy of the vaccination was blunted by the neutralization of IFN-γ. CD4+cells were necessary for the efficacy of the vaccination in both the afferent and efferent phases. Thus, we have demonstrated that this immunodominant antigen is a candidate for the development of a vaccine against this fungus.
Acinetobacter baylyi
as a Pathogen for Opportunistic Infection
Authors: Chen Te-Li , Siu Leung-Kei , Lee Yi-Tzu , Chen Chien-Pei , Huang Li-Yueh , Wu Roy Chen-Chih , Cho Wen-Long , Fung Chang-Phone
Published: July 2008

There are no previous reports of human infection due to
Acinetobacter baylyi
. In this study, we report on six patients with bacteremia due to
A. baylyi
, based on analysis of the 16S-23S rRNA intergenic spacer and the 16S rRNA gene. All six patients had multiple underlying diseases. The infection was nosocomially acquired in five patients. The six clinical isolates had similar ribopatterns, suggesting a clonal relationship. Compared to the reference strain, the clinical isolates were more resistant to antimicrobial agents, especially beta-lactam antibiotics. In three of the isolates, they may have undetermined plasmid mediated class C type beta-lactamases because of the positive results in a double-disk synergy test using 3-aminophenylboronic acid. Two of the clinical isolates retained a level of natural transformability similar to that of the reference strain. None of the patients died, although only three of them received appropriate antimicrobial therapy. This study demonstrates that
A. baylyi
is a potential human pathogen that can cause nosocomial infection in immunocompromised patients.
Efficacy of Dry Mist of Hydrogen Peroxide (DMHP) against
Mycobacterium tuberculosis
and use of DMHP for Routine Decontamination of Biosafety Level 3 Laboratories
Authors: Grare M. , Dailloux M. , Simon L. , Dimajo P. , Laurain C.
Published: July 2008

Mycobacterium tuberculosis
is a major cause of morbidity and mortality worldwide and is becoming a greater concern due to the development of multidrug-resistant strains.
M. tuberculosis
can contaminate rooms, medical equipment, and research laboratories and has the propensity to be highly resistant to decontamination. The aim of this study was to determine the efficacy of room disinfection with a dry mist of hydrogen peroxide (DMHP) in a biosafety level 3 laboratory in the event of contamination with
M. tuberculosis
. The biological indicators (BIs) were comprised of presterilized cotton tissues on which amounts of about 10
7
CFU/ml of
M. tuberculosis
H37Ra were dried. The device (Sterinis; Gloster Sante Europe) provided a DMHP of 5% hydrogen peroxide during 25 min. Three experiments were performed. The viable bacteria were reduced by values of more than 5 log
10
, and no colony grew from any BI. In conclusion, DMHP shows promise as an effective and safe alternative to the currently used formaldehyde.
Two Unusual Occurrences of Trichomoniasis: Rapid Species Identification by PCR
Authors: Bellanger A. P. , Cabaret O. , Costa J. M. , Foulet F. , Bretagne S. , Botterel F.
Published: July 2008

PCR analysis in two unusual occurrences of trichomoniasis, trichomonal empyema due to
Trichomonas tenax
and
Trichomonas vaginalis
in an infant urine sample, allowed us to obtain rapid and accurate trichomonad species identification. The weak sensitivity of wet preparations and the low viability of the flagellates can be remedied by the PCR method.
Multiplex Tandem PCR: a Novel Platform for Rapid Detection and Identification of Fungal Pathogens from Blood Culture Specimens
Authors: Lau Anna , Sorrell Tania C. , Chen Sharon , Stanley Keith , Iredell Jonathan , Halliday Catriona
Published: July 2008

We describe the first development and evaluation of a rapid multiplex tandem PCR (MT-PCR) assay for the detection and identification of fungi directly from blood culture specimens that have been flagged as positive. The assay uses a short-cycle multiplex amplification, followed by 12 simultaneous PCRs which target the fungal internal transcribed spacer 1 (ITS1) and ITS2 region, elongation factor 1-α (EF1-α), and β-tubulin genes to identify 11 fungal pathogens:Candida albicans, Candida dubliniensis, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosiscomplex,Candida tropicalis, Cryptococcus neoformanscomplex,Fusarium solani, Fusariumspecies, andScedosporium prolificans. The presence or absence of a fungal target was confirmed by melting curve analysis. Identification by MT-PCR correlated with culture-based identification for 44 (100%) patients. No cross-reactivity was detected in 200 blood culture specimens that contained bacteria or in 30 blood cultures without microorganisms. Fungi were correctly identified in five specimens with bacterial coinfection and in blood culture samples that were seeded with a mixture of yeast cells. The MT-PCR assay was able to provide rapid (<2 h), sensitive, and specific simultaneous detection and identification of fungal pathogens directly from blood culture specimens.
Bartonellasp. Bacteremia in Patients with Neurological and Neurocognitive Dysfunction
Authors: Breitschwerdt E. B. , Maggi R. G. , Nicholson W. L. , Cherry N. A. , Woods C. W.
Published: July 2008

We detected infection with aBartonellaspecies (B. henselaeorB. vinsoniisubsp.berkhoffii) in blood samples from six immunocompetent patients who presented with a chronic neurological or neurocognitive syndrome including seizures, ataxia, memory loss, and/or tremors. Each of these patients had substantial animal contact or recent arthropod exposure as a potential risk factor forBartonellainfection. Additional studies should be performed to clarify the potential role ofBartonellaspp. as a cause of chronic neurological and neurocognitive dysfunction.
Comparison of the Luminex xTAG Respiratory Viral Panel with In-House Nucleic Acid Amplification Tests for Diagnosis of Respiratory Virus Infections
Authors: Pabbaraju Kanti , Tokaryk Kara L. , Wong Sallene , Fox Julie D.
Published: July 2008

Detection of respiratory viruses using sensitive real-time nucleic acid amplification tests (NATs) is invaluable for patient and outbreak management. However, the wide range of potential respiratory virus pathogens makes testing using individual real-time NATs expensive and laborious. The objective of this study was to compare the detection of respiratory virus targets using the Luminex xTAG respiratory viral panel (RVP) assay with individual real-time NATs used at the Provincial Laboratory of Public Health, Calgary, Alberta, Canada. The study included 1,530 specimens submitted for diagnosis of respiratory infections from December 2006 to May 2007. Direct-fluorescent-antigen-positive nasopharyngeal samples were excluded from this study. A total of 690 and 643 positives were detected by RVP and in-house NATs, respectively. Kappa correlation between in-house NATs and RVP for all targets ranged from 0.721 to 1.000. The majority of specimens missed by in-house NATs (96.7%) were positive for picornaviruses. Samples missed by RVP were mainly positive for adenovirus (51.7%) or respiratory syncytial virus (27.5%) by in-house NATs and in general had low viral loads. RVP allows for multiplex detection of 20 (and differentiation between 19) respiratory virus targets with considerable time and cost savings compared with alternative NATs. Although this first version of the RVP assay has lower sensitivity than in-house NATs for detection of adenovirus, it has good sensitivity for other targets. The identification of picornaviruses and coronaviruses and concurrent typing of influenza A virus by RVP, which are not currently included in our diagnostic testing algorithm, will improve our diagnosis of respiratory tract infections.
Cleavage of Poly(A)-Binding Protein by Poliovirus 3C Proteinase Inhibits Viral Internal Ribosome Entry Site-Mediated Translation
Authors: Bonderoff Jennifer M. , LaRey Jennifer L. , Lloyd Richard E.
Published: July 2008

The two enteroviral proteinases, 2A proteinase (2A
pro
) and 3C proteinase (3C
pro
), induce host cell translation shutoff in enterovirus-infected cells by cleaving canonical translation initiation factors. Cleavage of poly(A)-binding protein (PABP) by 3C
pro
has been shown to be a necessary component for host translation shutoff. Here we show that 3C
pro
inhibits cap-independent translation mediated by the poliovirus internal ribosome entry site (IRES) in a dose-dependent manner in HeLa translation extracts displaying cap-poly(A) synergy. This effect is independent of the stimulatory effect of 2A
pro
on IRES translation, and 3C
pro
-induced translation inhibition can be partially rescued by addition of recombinant PABP in vitro. 3C
pro
inhibits IRES translation on transcripts containing or lacking poly(A) tails, suggesting that cleavage of PABP and IRES
trans
-activating factors polypyrimidine tract-binding protein and poly r(C)-binding protein 2 may also be important for inhibition. Expression of 3C
pro
cleavage-resistant PABP in cells increased translation of nonreplicating viral minigenome reporter RNAs during infection and also delayed and reduced virus protein synthesis from replicating RNA. Further, expression of cleavage-resistant PABP in cells reduced the accumulation of viral RNA and the output of infectious virus. These results suggest that cleavage of PABP contributes to viral translation shutoff that is required for the switch from translation to RNA replication.
Leader of the Capsid Protein in Feline Calicivirus Promotes Replication of Norwalk Virus in Cell Culture
Authors: Chang Kyeong-Ok , George David W. , Patton John B. , Green Kim Y. , Sosnovtsev Stanislav V.
Published: July 2008

The inability to grow human noroviruses in cell culture has greatly impeded the studies of their pathogenesis and immunity. Vesiviruses, in the family
Caliciviridae
, grow efficiently in cell culture and encode a unique protein in the subgenomic region designated as leader of the capsid protein (LC). We hypothesized that LC might be associated with the efficient replication of vesiviruses in cell culture and promote the replication of human norovirus in cells. To test this hypothesis, a recombinant plasmid was engineered in which the LC region of feline calicivirus (FCV) was placed under the control of the cytomegalovirus promoter (pCI-LC) so that the LC protein could be provided in
trans
to replicating calicivirus genomes bearing a reporter gene. We constructed pNV-GFP, a recombinant plasmid containing a full-length NV genome with a green fluorescent protein (GFP) in the place of VP1. The transfection of pNV-GFP in MVA-T7-infected cells produced few GFP-positive cells detected by fluorescence microscopy and flow cytometry analysis. When pNV-GFP was cotransfected with pCI-LC in MVA-T7-infected cells, we observed an increase in the number of GFP-positive cells (ca. 3% of the whole-cell population). Using this cotransfection method with mutagenesis study, we identified potential
cis
-acting elements at the start of subgenomic RNA and the 3′ end of NV genome for the virus replication. We conclude that LC may be a viral factor which promotes the replication of NV in cells, which could provide a clue to growing the fastidious human noroviruses in cell culture.
Functional Homologies between Avian and Human Alphaherpesvirus VP22 Proteins in Cell-to-Cell Spreading as Revealed by a New
cis
-Complementation Assay
Authors: Blondeau C. , Marc D. , Courvoisier K. , Vautherot J.-F. , Denesvre C.
Published: July 2008

VP22, encoded by the
UL49
gene of Marek's disease virus (MDV), is indispensable for virus cell-to-cell spreading. We show herein that MDV
UL49
can be functionally replaced with avian and human viral orthologs. Replacement of MDV VP22 with that of avian gallid herpesvirus 3 or herpesvirus of turkey, whose residue identity with MDV is close to 60%, resulted in 73 and 131% changes in viral spreading, respectively. In contrast, VP22 replacement with human herpes simplex virus type 1 resulted in 14% plaque formation. Therefore, heterologous avian and human VP22 proteins share sufficient structural homology to support MDV cell-to-cell spreading, albeit with different efficiencies.
Pedometer counts superior to physical activity scale for identifying health markers in older adults
Authors: Ewald B , McEvoy M , Attia J
Published: July 2008

Objective

Measuring physical activity is a key part of studying its health effects. Questionnaires and pedometers each have weaknesses but are the cheapest and easiest to use measurement methods for large-scale studies. We examined their capacity to detect expected associations between physical activity and a range of surrogate health measures.

Design

Cross-sectional analysis of 669 community-dwelling participants (mean age 63.3 (7.7) years) who completed the Physical Activity Scale for the Elderly (PASE) questionnaire and who, within 2 weeks, wore a pedometer for 7 days.

Results

PASE score and step count were only poorly correlated (r = 0.37 in women, r = 0.30 in men). Of 12 expected associations examined between activity and surrogate markers of health, 10 were detected as statistically significant by step counts but only 3 by PASE scores. Significant associations in the expected direction were found between step counts and high-density lipoprotein, body mass index, waist circumference, waist-to-hip ratio, blood glucose level, white cell count and fibrinogen. There was no association with either systolic or diastolic blood pressure. The association between PASE score and these markers was detected as significant only for body mass index and waist circumference in women and waist-to-hip ratio in both sexes. Associations were stronger for steps multiplied by stride length than for raw step count.

Conclusions

Pedometer-derived step counts are a more valid measurement of overall physical activity in this sample than PASE score. Researchers should use objective measures of physical activity whenever possible.
STRUCTURAL AND ELECTRONIC PROPERTIES OF METAL-DOPED ORGANIC SEMICONDUCTORS
Authors: ZAZZA COSTANTINO , MELONI SIMONE , PALMA AMEDEO
Published: July 2008

Interaction of metal atoms with organic thin films is a fundamental issue in the optimization performances of novel devices. The computational investigations, based on density functional theory, reveal that a realistic description of the reactive processes is obtained when the organic thin film is modeled by its crystallographic structure. In this case, the metal atoms can react with multiple organic molecules present in the solid forming complexes where they are bound both to O atoms and to aromatic C atoms of the molecules. Calculated band gap states, induced by chemical reaction upon deposition, reproduce quite well the measured density of states as a function of the metal concentration in the solid. Simulated core level shift spectra for N (1s), O (1s) and Al (2p) in doped systems are in good agreement with experimental spectra and the electronic structure analysis provides a microscopic description of reaction processes. Interestingly, K atoms in PTCDA solid are ionically bound to anhydride O atoms and are able to form quasi mono-dimensional chain along the stack direction of the organic material.
EFFICIENT SHAPE-BASED IMAGE RETRIEVAL BASED ON GRAY RELATIONAL ANALYSIS AND ASSOCIATION RULES
Authors: HUANG YO-PING , CHANG TSUN-WEI , SANDNES FRODE EIKA
Published: July 2008

An improved shape based image retrieval strategy based on gray relational analysis and association rules is proposed. The choice of a suitable object representation and retrieval scheme is essential for efficient retrieval. In addition, a two-stage relevance feedback mechanism based on the GM(1, N) method and association rules is incorporated to improve the retrieval accuracy. The GM(1, N) method is used to build the re-query example for subsequent retrievals. The retrieval log files stored on the server are used for offline mining of association rules. The association rules mined from users' retrieval history can further reveal users' image searching behavior. The effectiveness of the proposed model is demonstrated on the FISH dataset.
EMERGENT CHAOS SYNCHRONIZATION IN NONCHAOTIC CNNS
Authors: YANG XIAO-SONG , YUAN QUAN
Published: July 2008

It is shown that emergent chaos synchronization can take place in coupled nonchaotic unit dynamical systems. This is demonstrated by coupling two nonchaotic cellular neural networks, in which the couplings give rise to a synchronous chaotic dynamics and in the meanwhile the synchronous dynamics is globally asymptotically stable, thus chaos synchronization takes place under the suitable couplings.
A FAMILY OF COMPLETELY PERIODIC QUADRATIC DISCRETE DYNAMICAL SYSTEM
Authors: KUTNJAK MILAN , MENCINGER MATEJ
Published: July 2008

There is a one-to-one correspondence between homogeneous quadratic dynamical systems and commutative (possibly nonassociative) algebras. The corresponding theory for continuous systems is well known (c.f. [Markus, 1960; Walcher, 1991; Kinyon & Sagle, 1995]). In this paper the dynamics on the boundary of the basin of attraction of the origin, ∂ B Att (0), in homogeneous quadratic discrete dynamical systems is considered. In particular, we consider the dynamical behavior in a family of systems corresponding to a family of algebras [Formula: see text] which admits nilpotents of rank 2 and idempotents. The complete periodicity of a system (and the corresponding algebra) is defined and it is proven that for every n > 2 there are some systems/algebras from [Formula: see text] which are on ∂ BAtt(0) completely periodic with period n. The dynamics on ∂ B Att (0) is considered via a special class of polynomials Pn, n ∈ ℕ ∪ {0, -1}, recursively defined by Pn(α) = 2αPn-2(α) + Pn-1(α); P-1(α) = 0, P0(α) = 1, n ∈ ℕ.
DESIGN OF METALLIC METAMATERIAL STRUCTURES AT HIGH FREQUENCIES
Authors: CHAKRABARTI SANGEETA , RAMAKRISHNA S. ANANTHA
Published: July 2008

We discuss the design of metamaterials made up of metallic structures that can have negative material parameters such as the dielectic permittivity (∊), the magnetic permeability (μ) and the refractive index (n), with a view to optimize their performance at high frequencies. We also discuss the behavior of metamaterials in the optical frequency regime where homogenization procedures become questionable. A medium consisting of an array of split ring resonators (SRRs) can have negative phase velocity (suggesting a negative index of refraction) for specific directions of incidence at optical frequencies. However, owing to the fact that the size of the SRR is comparable to the wavelength of the incident radiation, the electric fields interact strongly with even symmetric SRRs at these frequencies. The negative phase velocity is found to arise from plasmonic excitations of the SRR and we cannot describe this effect by means of the usual paradigm of negative permittivity and negative permeability. The focusing of light by arrays of SRRs (both ordered and disordered) in the manner of the Veselago lens is presented. The results show that the focusing properties and the negative phase velocity arise primarily from excitations of localized resonances and not from Bragg scattering.
NEW CONCEPTS WITH SURFACE PLASMONS AND NANO-BIOINTERFACES
Authors: KNOLL WOLFGANG , KASRY AMAL , YU FANG , WANG YI , BRUNSEN ANNETTE , DOSTÁLEK JAKUB
Published: July 2008

In classical surface plasmon-based optical biosensors, a surface plasmon mode is resonantly excited on the metallic sensor surface to probe any analyte-binding-induced refractive index changes. The field of the surface plasmon mode evanescently decays from the metal into an adjacent analyte solution with a typical penetration depth of 200 nm. In order to maximize the sensitivity of SPR biosensors, interfacial polymer architectures with binding site densities that considerably exceed planar arrangements through the use of three-dimensional microstructures were introduced. For biosensors based on surface plasmon fluorescence spectroscopy, this type of matrix offers the additional advantage of preventing fluorescence quenching, which is caused by the proximity of the chromophore label to the acceptor states of the noble metal. By means of probing the binding events with long range surface plasmon modes of which field extend much farther into the analyte solution (up to the micrometer range), substantially thicker sensor matrix layers can be used. Into such matrices larger amounts of ligands can be loaded, which enables one to increase the surface density of binding sites and thus to enhance the sensitivity of the biosensor. We present results which show that functionalized hydrogels are very well suited for meeting the demands of these novel biosensor platforms.
MULTIWAVELENGTH SOURCE USING A BRILLOUIN FIBER LASER
Authors: HARUN S. W. , SHIRAZI M. R. , ABDUL-RASHID H. A. , AHMAD H.
Published: July 2008

A multiwavelength laser operating on the basis of stimulated Brillouin scattering (SBS) is demonstrated in a single mode fiber (SMF) coupled with a feedback loop and an optical circulator. Ten simultaneous Stokes and anti-Stokes lines are obtained with a line spacing of either 0.08 or 0.16 nm at a Brillouin pump (BP) power of 14 dBm. The use of a 50/50 fused coupler gives the highest number of lines at a Stokes power of approximately 8 dBm. The anti-Stokes lines are generated by four-wave mixing and bidirectional operation of the system. This Brillouin fiber laser (BFL) is capable of operating at any wavelength, depending completely on the BP wavelength. Due to the built-in feedback mechanism, its operation is free from the need for any additional active linear gain medium, such as erbium-doped fibers used in a Brillouin erbium fiber laser. Further, the SMF can in principle be replaced with a highly nonlinear waveguide, such as a photonic crystal waveguide, to make a compact multiwavelength BFL.
Adiponectin deficiency promotes endothelial activation and profoundly exacerbates sepsis-related mortality
Authors: Teoh Hwee , Quan Adrian , Bang K. W. Annie , Wang Guilin , Lovren Fina , Vu Vivian , Haitsma Jack J. , Szmitko Paul E. , Al-Omran Mohammed , Wang Chao-Hung , Gupta Milan , Peterson Mark D. , Zhang Haibo , Chan Lawrence , Freedman John , Sweeney Gary , Verma Subodh
Published: July 2008

Sepsis is a multifactorial, and often fatal, disorder typically characterized by widespread inflammation and immune activation with resultant endothelial activation. In the present study, we postulated that the adipokine adiponectin serves as a critical modulator of survival and endothelial activation in sepsis. To this aim, we evaluated both loss-of-function (adiponectin gene-deficient mice) and subsequent gain-of-function (recombinant adiponectin reconstitution) strategies in two well-established inflammatory models, cecal ligation perforation (CLP) and thioglyocollate-induced peritonitis. Adipoq−/− mice, subjected to CLP, exhibited a profound (∼8-fold) reduction in survival compared with their wild-type Adipoq+/+ littermates after 48 h. Furthermore, compared with wild-type controls, thioglycollate challenge resulted in a markedly greater influx of peritoneal neutrophils in Adipoq−/− mice accompanied by an excess production of key chemoattractant cytokines (IL-12p70, TNFα, MCP-1, and IL-6) and upregulation of aortic endothelial adhesion molecule VCAM-1 and ICAM-1 expressions. Importantly, all of these effects were blunted by recombinant total adiponectin administration given 3 days prior to thioglycollate challenge. The protective effects of adiponectin were ascribed largely to higher-order adiponectin oligomers, since administration of recombinant C39A trimeric adiponectin did not attenuate endothelial adhesion molecule expression in thioglycollate-challenged Adipoq−/− mice. These data suggest a critical role of adiponectin as a modulator of survival and endothelial inflammation in experimental sepsis and a potential mechanistic link between adiposity and increased sepsis.
A megalin-like receptor is involved in protein endocytosis in the midgut of an insect (Bombyx mori, Lepidoptera)
Authors: Casartelli M. , Cermenati G. , Rodighiero S. , Pennacchio F. , Giordana B.
Published: July 2008

The mechanism responsible for fluorescein isothiocyanate (FITC)-albumin internalization by columnar cells in culture obtained from the midgut of Bombyx mori larvae was examined by confocal laser scanning microscopy. Protein uptake changed over time, and it appeared to be energy dependent, since it was strongly reduced by both low temperatures and metabolic inhibitors. Labeled albumin uptake as a function of increasing protein concentration showed a saturation kinetics with a Michaelis constant value of 2.0 ± 0.6 μM. These data are compatible with the occurrence of receptor-mediated endocytosis. RT-PCR analysis and colocalization experiments with an anti-megalin primary antibody indicated that the receptor involved was a putative homolog of megalin, the multiligand endocytic receptor belonging to the low-density lipoprotein receptor family, responsible for the uptake of various molecules, albumin included, in many epithelial cells of mammals. This insect receptor, like the mammalian counterpart, required Ca2+for albumin internalization and was inhibited by gentamicin. FITC-albumin internalization was clathrin mediated, since two inhibitors of this process caused a significant reduction of the uptake, and clathrin and albumin colocalized in the intermicrovillar areas of the apical plasma membrane. The integrity of actin and microtubule organization was essential for the correct functioning of the endocytic machinery.
Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats
Authors: Chen Sung-Lang , Huang Yu-Hui , Kao Yu-Lin , Chen Gin-Den , Cheng Chen-Li , Peng Hsien-Yu , Liao Jiuan-Miaw , Huang Pei-Chen , Tsai Shih-Jei , Lin Tzer-Bin
Published: July 2008

The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 μM, 10 μl) and d-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-d-aspartate (NMDA) antagonist, 100 μM, 10 μl]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 μM, 10 μl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [γ-aminobutyric acid (GABA) A receptor antagonist, 100 μM, 10 μl] but not hydroxysaclofen (GABABreceptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.
Human H+ATPase a4 subunit mutations causing renal tubular acidosis reveal a role for interaction with phosphofructokinase-1
Authors: Su Ya , Blake-Palmer Katherine G. , Sorrell Sara , Javid Babak , Bowers Katherine , Zhou Aiwu , Chang Simon H. , Qamar Seema , Karet Fiona E.
Published: July 2008

The vacuolar-type ATPase (H+ATPase) is a ubiquitously expressed multisubunit pump whose regulation is poorly understood. Its membrane-integral a-subunit is involved in proton translocation and in humans has four forms, a1–a4. This study investigated two naturally occurring point mutations in a4's COOH terminus that cause recessive distal renal tubular acidosis (dRTA), R807Q and G820R. Both lie within a domain that binds the glycolytic enzyme phosphofructokinase-1 (PFK-1). We recreated these disease mutations in yeast to investigate effects on protein expression, H+ATPase assembly, targeting and activity, and performed in vitro PFK-1 binding and activity studies of mammalian proteins. Mammalian studies revealed complete loss of binding between the COOH terminus of a4 containing the G-to-R mutant and PFK-1, without affecting PFK-1's catalytic activity. In yeast expression studies, protein levels, H+ATPase assembly, and targeting of this mutant were all preserved. However, severe (78%) loss of proton transport but less decrease in ATPase activity (36%) were observed in mutant vacuoles, suggesting a requirement for the a-subunit/PFK-1 binding to couple these two functions. This role for PFK in H+ATPase function was supported by similar functional losses and uncoupling ratio between the two proton pump domains observed in vacuoles from a PFK-null strain, which was also unable to grow at alkaline pH. In contrast, the R-to-Q mutation dramatically reduced a-subunit production, abolishing H+ATPase function completely. Thus in the context of dRTA, stability and function of the metabolon composed of H+ATPase and glycolytic components can be compromised by either loss of required PFK-1 binding (G820R) or loss of pump protein (R807Q).
Neurons in the Pontomedullary Reticular Formation Signal Posture and Movement Both as an Integrated Behavior and Independently
Authors: Schepens Bénédicte , Stapley Paul , Drew Trevor
Published: July 2008

We have previously suggested that the discharge characteristics of some neurons in the pontomedullary reticular formation (PMRF) are contingent on the simultaneous requirement for activity in both ipsilateral flexor muscles and contralateral extensors. To test this hypothesis we trained cats to stand on four force platforms and to perform a task in which they were required to reach forward with one forelimb or the other and depress a lever. As such the task required the cat to make a flexion movement followed by an extension in the reaching limb while maintaining postural support by increasing extensor muscle tonus in the supporting limbs. We recorded the activity of 131 neurons from the PMRF of three cats during left, ipsilateral reach. Of these, 86/131 (66%) showed a change in discharge frequency prior to the onset of activity in one of the prime flexor muscles and 43/86 (50%) showed a bimodal pattern of discharge in which activity decreased during the lever press. Among the remaining cells, 28/86 (33%) showed maintained activity throughout the reach and the lever press. Most cells showed a broadly similar pattern of discharge during reaches with the right, contralateral limb. We suggest these results support the view that a population of neurons within the PMRF contributes to the control of movement in one forelimb and the control of posture in the other forelimb as a coordinated unit. Another population of neurons contributes to the control of postural support independently of the nature of the activity in the reaching limb.
The Galileo Ground Segment Integrity Algorithms: Design and Performance
Authors: Medel Carlos Hernández , Catalán Carlos Catalán , Fernández Vidou Miguel Angel , Sardón Pérez Esther
Published: July 2008

Galileo, the European Global Navigation Satellite System, will provide to its users highly accurate global positioning services and their associated integrity information. The element in charge of the computation of integrity messages within the Galileo Ground Mission Segment is the integrity processing facility (IPF), which is developed by GMV Aerospace and Defence. The main objective of this paper is twofold: to present the integrity algorithms implemented in the IPF and to show the achieved performance with the IPF software prototype, including aspects such as: implementation of the Galileo overbounding concept, impact of safety requirements on the algorithm design including the threat models for the so‐called feared events, and finally the achieved performance with real GPS and simulated Galileo scenarios.