bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Protein Binding on the Pharmacological Activity of Highly Bound Antibiotics
Authors: Schmidt Stephan , Röck Katharina , Sahre Martina , Burkhardt Olaf , Brunner Martin , Lobmeyer Maximilian T. , Derendorf Hartmut
Published: September 2008

During antibiotic drug development, media are frequently spiked with either serum/plasma or protein supplements to evaluate the effect of protein binding. Usually, previously reported serum or plasma protein binding values are applied in the analysis. The aim of this study was to evaluate this approach by experimentally measuring free, unbound concentrations for antibiotics with reportedly high protein binding and their corresponding antimicrobial activities in media containing commonly used protein supplements. Free, unbound ceftriaxone and ertapenem concentrations were determined in bacterial growth medium with and without bovine/human serum albumin, as well as adult bovine serum and human plasma using in vitro microdialysis. The corresponding antimicrobial activity was determined in MIC and time-kill curve experiments using
Escherichia coli
ATCC 25922 and
Streptococcus pneumoniae
ATCC 6303 as test strains. A semimechanistic maximum effect model was simultaneously fitted to the data and respective EC
50
(concentration at half-maximum effect) values compared. Protein binding differed significantly for ceftriaxone (
P
< 0.05) between human plasma (76.8 ± 11.0%) and commercially available bovine (20.2 ± 8.3%) or human serum albumin (56.9 ± 16.6%). Similar results were obtained for ertapenem (human plasma, 73.8 ± 11.6%; bovine serum albumin, 12.4 ± 4.8%; human serum albumin, 17.8 ± 11.5%). The MICs and EC
50
s of both strains were significantly increased (
P
< 0.05) for ceftriaxone when comparing human and bovine serum albumin, whereas the EC
50
s were not significantly different for ertapenem. Free, unbound antibiotic concentrations differed substantially between plasma and protein supplements and correlated well with antimicrobial efficacy. Therefore, free, active concentrations should be measured in the test system instead of correcting for literature protein binding values.
Development, Stability, and Molecular Mechanisms of Macrolide Resistance in
Campylobacter jejuni
Authors: Caldwell Dave Bryson , Wang Ying , Lin Jun
Published: September 2008

Previous studies of macrolide resistance in
Campylobacter
were primarily focused on strains from various origins or used in vitro systems. In this study, we conducted both in vitro and in vivo experiments to examine the development, stability, and genetic basis of macrolide resistance in
Campylobacter jejuni
using erythromycin-resistant (Ery
r
) mutants derived from the same parent strain. Chickens inoculated with low-level Ery
r
mutants (MIC = 32 or 64 μg/ml) at 15 days old did not shed highly Ery
r
mutants (MIC > 512 μg/ml) after prolonged exposure to a low dose of tylosin. The low-level Ery resistance was not stable in vitro or in vivo in the absence of macrolide selection pressure. However, high-level Ery resistance displayed remarkable stability in vitro and in vivo. Ribosomal sequence analysis of 69 selected Ery
r
mutants showed that specific point mutations (A2074G or A2074C) occurred in all highly Ery
r
mutants. No mutations in ribosomal protein L4 were observed in any of the in vitro-selected Ery
r
mutants. However, three specific mutations in L4, G74D, G57D, and G57V, were widely found among in vivo-selected Ery
r
mutants. Insertion of three amino acids, TSH, at position 98 in ribosomal protein L22 was observed only in mutants selected in vitro. Inactivation of the CmeABC efflux pump dramatically reduced Ery MICs in Ery
r
mutants. Together, these findings suggest that multiple factors contribute to the emergence of highly Ery
r
Campylobacter
in chicken, reveal resistance level-dependent stability of macrolide resistance in
C. jejuni
, and indicate that
C. jejuni
utilizes complex and different mechanisms to develop Ery resistance in vitro and in vivo.
Genetic Analysis of Fenhexamid-Resistant Field Isolates of the Phytopathogenic Fungus
Botrytis cinerea
Authors: Fillinger Sabine , Leroux Pierre , Auclair Christiane , Barreau Christian , Al Hajj Charbel , Debieu Danièle
Published: September 2008

The hydroxyanilide fenhexamid, one of the latest antibotrytis fungicides, active especially against leotiomycete plant-pathogenic fungi, inhibits 3-ketoreductase of the C-4-demethylation enzyme complex during ergosterol biosynthesis. We isolated
Botrytis cinerea
strains resistant to various levels of fenhexamid from French and German vineyards. The sequence of the gene encoding 3-ketoreductase,
erg27
, varied according to levels of resistance. Highly resistant isolates, termed HydR3
+
, all presented a modification of the phenylalanine at the C terminus of the putative transmembrane domain at position 412, either to serine (85% of the isolates), to isoleucine (11.5% of the isolates), or to valine (3.5% of the isolates). The introduction of the

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allele into a fenhexamid-sensitive strain by means of a replicative plasmid conferred fenhexamid resistance on the resulting transformants, showing that the mutations at position 412 are responsible for fenhexamid resistance. Weakly to moderately resistant isolates, termed HydR3
−
, showed different point mutations between the strains in the sequenced regions of the
erg27
gene, corresponding to amino acid changes between positions 195 and 400 of the protein. The

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(erg27^{HydR3^{{-}}}\) \end{document}

alleles on the replicative vector introduced into a sensitive strain did not confer resistance to fenhexamid. Genetic crosses between HydR3
−
and sensitive strains showed strict correlation between the sequenced mutation in the
erg27
gene and the resistance phenotypes, suggesting that these mutations are linked to fenhexamid resistance. The HydR3 mutations possibly modify the affinity of the 3-ketoreductase enzyme for its specific inhibitor, fenhexamid.
Identification of the Genetic Basis for Clinical Menadione-Auxotrophic Small-Colony Variant Isolates of
Staphylococcus aureus
Authors: Lannergård Jonas , von Eiff Christof , Sander Gunnar , Cordes Tina , Seggewiβ Jochen , Peters Georg , Proctor Richard A. , Becker Karsten , Hughes Diarmaid
Published: September 2008

Small-colony variants (SCVs) of
Staphylococcus aureus
are associated with persistent infections and may be selectively enriched during antibiotic therapy. Three pairs of clonally related
S. aureus
isolates were recovered from patients receiving systemic antibiotic therapy. Each pair consisted of an isolate with a normal phenotype and an isolate with an SCV phenotype. These SCVs were characterized by reduced susceptibility to gentamicin, reduced hemolytic activity, slow growth, and menadione auxotrophy. Sequencing of the genes involved in menadione biosynthesis revealed mutations in
menB
, the gene encoding naphthoate synthase, in all three strains with the SCV phenotype. The
menB
mutations were (i) a 9-bp deletion from nucleotides 55 to 63, (ii) a frameshift mutation that resulted in a premature stop codon at position 230, and (iii) a point mutation that caused the amino acid substitution Gly to Val at codon 233. Fluctuation tests showed that growth-compensated mutants arose in the SCV population of one strain, strain OM1b, at a rate of 1.8 × 10
−8
per cell per generation. Sequence analyses of 23 independently isolated growth-compensated mutants of this strain revealed alterations in the
menB
sequence in every case. These alterations included reversions to the wild-type sequence and intragenic second-site mutations. Each of the growth-compensated mutants showed a restoration of normal growth and a loss of menadione auxotrophy, increased susceptibility to gentamicin, and restored hemolytic activity. These data show that mutations in
menB
cause the SCV phenotype in these clinical isolates. This is the first report on the genetic basis of menadione-auxotrophic SCVs determined in clinical
S. aureus
isolates.
Recovery of a Functional Class 2 Integron from an
Escherichia coli
Strain Mediating a Urinary Tract Infection
Authors: Márquez Carolina , Labbate Maurizio , Ingold Ana J. , Chowdhury Piklu Roy , Ramírez Maria S. , Centrón Daniela , Borthagaray Graciela , Stokes H. W.
Published: September 2008

A class 2 integron was found in an
Escherichia coli
isolate mediating a urinary tract infection. Unlike other class 2 integrons from pathogens, the encoded IntI2 protein was functional. The integron possessed a
dfrA14
cassette, and a second novel cassette in which a lipoprotein signal peptidase gene is predicted.
Inhibition of Voriconazole Metabolism by Chloramphenicol in an Adolescent with Central Nervous System Aspergillosis
Authors: Hafner Verena , Albermann Nadine , Haefeli Walter E. , Ebinger Friedrich
Published: September 2008

For an adolescent with bacterial meningitis and subsequent cerebral aspergillosis, intravenous voriconazole dose requirements substantially decreased during coadministration with intravenous chloramphenicol and considerably rose after discontinuation of the antibiotic. In agreement with in vitro evidence, these data suggest that chloramphenicol is a rather significant inhibitor of hepatic CYP3A4 and/or CYP2C19.
Outer Surface Protein A Protects Lyme Disease Spirochetes from Acquired Host Immunity in the Tick Vector
Authors: Battisti James M. , Bono James L. , Rosa Patricia A. , Schrumpf Merry E. , Schwan Tom G. , Policastro Paul F.
Published: September 2008

The Lyme disease spirochete
Borrelia burgdorferi
alters the expression of outer surface protein (
osp
) genes as the bacterium cycles between ticks and mammals. OspA is produced as borreliae enter the tick vector and remains a major surface antigen during midgut colonization. To elucidate the role of OspA in the vector, we created an insertional deletion of
ospA
in strain B31-A3. The
ospA
mutant infects mice when it is injected intradermally and is acquired by larval ticks fed on these mice, where it persists through the molt to the nymph stage. Bacterial survival rates in artificially infected tick larvae fed on naïve mice were compared with those in the vector fed on immune mice. The
ospA
mutant proliferates in larvae if it is exposed to blood from naïve mice, but it declines in density after larval feeding if the blood is from immune mice. When uninfected larvae are fed on B-cell-deficient mice infected with the
ospA
mutant, larvae show borrelial densities and persistence that are significantly greater than those fed on infected, immunocompetent mice. We conclude that OspA serves a critical antibody-shielding role during vector blood meal uptake from immune hosts and is not required for persistence in the tick vector.
Role of Natural Killer Cells in Modulating Dendritic Cell Responses toLeishmania amazonensisInfection
Authors: Sanabria Mayra X. Hernandez , Vargas-Inchaustegui Diego A. , Xin Lijun , Soong Lynn
Published: September 2008

The importance of the interaction between natural killer (NK) cells and dendritic cells (DCs) in the expansion of antiviral and antitumor immune responses is well-documented; however, limited information on DC-NK cell interaction during parasitic infections is available. Given that someLeishmaniaparasites are known to prevent or suppress DC activation, we developed a DC-NK cell coculture system to examine the role of NK cells in modulating the functions ofLeishmania-infected DCs. We found that the addition of freshly isolated, resting NK cells significantly promoted the activation of DCs that were preinfected withLeishmania amazonensispromastigotes and that these activated DCs, in turn, stimulated NK cell activation mostly via cell contact-dependent mechanisms. Notably,L. amazonensisamastigote infection failed to activate DCs, and this lack of DC activation could be partially reversed by the addition of preactivated NK (ANK) cells but not resting NK cells. Moreover, the adoptive transfer of ANK cells intoL. amazonensis-infected mice markedly increased DC and T-cell activation and reduced tissue parasite loads at 1 and 3 weeks postinfection. These results suggest differential roles of DC-NK cell cross talk at different stages ofLeishmaniainfection and provide new insight into the interplay of components of the innate immune system during parasitic infection.
Association ofMycoplasma arthritidisMitogen with Lethal Toxicity but Not with Arthritis in Mice
Authors: Luo Wenyi , Yu Huilan , Cao Zuhua , Schoeb Trenton R. , Marron Michele , Dybvig Kevin
Published: September 2008

Mycoplasma arthritidisinduces an acute to chronic arthritis in rodents. Arthritis induced in mice histologically resembles human rheumatoid arthritis and can be associated with lethal toxicity following systemic injection. TheM. arthritidismitogen (MAM) superantigen has long been implicated as having a role in pathogenesis, but its significance with respect to toxicity and arthritogenicity in mycoplasma-induced disease is unclear. To study the pathogenic significance of MAM,M. arthritidismutants that overproduced or failed to produce MAM were developed. MAM overproduction and knockout mutants were more and less mitogenic, respectively, than the wild-type strain. The degree of mitogenic activity correlated with lethal toxicity in DBA/2J mice. In contrast, histopathological studies detected no correlation between MAM production and the severity of arthritis induced in DBA/2J and CBA/J mice.
Trypanosoma cruziInfection Is Enhanced by Vector Saliva through Immunosuppressant Mechanisms Mediated by Lysophosphatidylcholine
Authors: Mesquita Rafael D. , Carneiro Alan Brito , Bafica André , Gazos-Lopes Felipe , Takiya Christina M. , Souto-Padron Thaís , Vieira Danielle P. , Ferreira-Pereira Antônio , Almeida Igor C. , Figueiredo Rodrigo T. , Porto Bárbara N. , Bozza Marcelo T. , Graça-Souza Aurélio V. , Lopes Angela H. C. S. , Atella Geórgia C. , Silva-Neto Mário A. C.
Published: September 2008

Trypanosoma cruzi, the etiological agent of Chagas disease, is transmitted by bug feces deposited on human skin during a blood meal. However, parasite infection occurs through the wound produced by insect mouthparts. Saliva of the Triatominae bugRhodnius prolixusis a source of lysophosphatidylcholine (LPC). Here, we tested the role of both triatomine saliva and LPC on parasite transmission. We show that vector saliva is a powerful inducer of cell chemotaxis. A massive number of inflammatory cells were found at the sites where LPC or saliva was inoculated into the skin of mice. LPC is a known chemoattractant for monocytes, but neutrophil recruitment induced by saliva is LPC independent. The preincubation of peritoneal macrophages with saliva or LPC increased fivefold the association ofT. cruziwith these cells. Moreover, saliva and LPC block nitric oxide production byT. cruzi-exposed macrophages. The injection of saliva or LPC into mouse skin in the presence of the parasite induces an up-to-sixfold increase in blood parasitemia. Together, our data suggest that saliva of the Triatominae enhancesT. cruzitransmission and that some of its biological effects are attributed to LPC. This is a demonstration that a vector-derived lysophospholipid may act as an enhancing factor of Chagas disease.
RecombinantBacillus subtilisExpressing theClostridium perfringensAlpha Toxoid Is a Candidate Orally Delivered Vaccine against Necrotic Enteritis
Authors: Hoang Tran H. , Hong Huynh A. , Clark Graeme C. , Titball Richard W. , Cutting Simon M.
Published: September 2008

RecombinantBacillus subtilisendospores have been used to vaccinate against tetanus and anthrax. In this work, we have developed spores that could be used to vaccinate againstClostridium perfringensalpha toxin and that could be used to protect against gas gangrene in humans and necrotic enteritis in poultry. The primary active agent in both cases is alpha toxin. A carboxy-terminal segment of the alpha toxin gene (cpa) fused to the glutathione-S-transferase (GST) gene was cloned inB. subtilissuch that the encoded GST-Cpa247-370polypeptide had been expressed in the following three different ways: expression in the vegetative cell, expression on the surface of the spore coat (fused to the CotB spore coat protein), and a combined approach of spore coat expression coupled with expression in the vegetative cell. Mice immunized orally or nasally with three doses of recombinant spores that carried GST-Cpa247-370on the spore surface showed the most striking responses. This included seroconversion with anti-Cpa247-370-specific immunoglobulin G (IgG) responses in their sera, a Th2 bias, and secretory IgA responses in saliva, feces, and lung samples. Neutralizing IgG antibodies to alpha toxin were detected using in vitro and in vivo assays, and a toxin challenge established protection. Mice immunized nasally or orally with recombinant spores were protected against a challenge with 12 median lethal doses of alpha toxin. Existing use of spores as competitive exclusion agents in animal feeds supports their use as a potentially economical and heat-stable vaccine for the poultry industry.
Characterization of a Unique ClpB Protein of
Mycoplasma pneumoniae
and Its Impact on Growth
Authors: Kannan T. R. , Musatovova Oxana , Gowda Pramod , Baseman Joel B.
Published: September 2008

Mycoplasma pneumoniae
accounts for 20 to 30% of all community-acquired pneumonia and has been associated with other airway pathologies, including asthma, and a range of extrapulmonary manifestations. Although the entire genomic sequence of
M. pneumoniae
has been completed, the functions of many of these genes in mycoplasma physiology are unknown. In this study, we focused on
clpB
, a well-known heat shock gene in other bacteria, to examine its role in mycoplasma growth. Transcriptional and translational analyses of heat shock in
M. pneumoniae
indicated that
clpB
is significantly upregulated, reinforcing its status as a critical responder to heat stress. Interestingly,
M. pneumoniae
ClpB does not use dual translational start points for ClpB synthesis, like other ClpB-characterized bacteria. Biochemical characterization of purified
M. pneumoniae
recombinant ClpB revealed casein- and lysine-independent ATPase activity and DnaK-DnaJ-GrpE-dependent chaperone activity. An
M. pneumoniae
mini-Tn
4001
-integrated,
clpB
-null mutant was impaired in its ability to replicate under permissive growth conditions, demonstrating the growth-promoting status of ClpB.
Serotype-Specific Immune Unresponsiveness to Pneumococcal Conjugate Vaccine following Invasive Pneumococcal Disease
Authors: Borrow Ray , Stanford Elaine , Waight Pauline , Helbert Matthew , Balmer Paul , Warrington Rosalind , Slack Mary , George Robert , Miller Elizabeth
Published: September 2008

Following the introduction of the pneumococcal 7-valent conjugate vaccine (PCV7) into the routine infant immunization schedule in England, Wales, and Northern Ireland, pneumococcal serotype-specific immunoglobulin G (IgG) antibody testing was offered as a clinical service to all children within the program with invasive pneumococcal disease (IPD) to confirm an adequate antibody response to PCV7. As of March 2008, serum samples taken within 14 to 90 days of vaccination had been submitted from 107 children who had received one or more doses in the second year of life. Sera were assayed by a multiplexed microsphere assay incorporating both cell wall polysaccharide and serotype 22F adsorption. A protective serotype-specific antibody level was defined as a concentration of ≥0.35 μg/ml. Eight children failed to develop a response to their infecting serotype (6B [
n
= 4], 18C [
n
= 2], 4 [
n
= 1], and 14 [
n
= 1]), despite receiving at least three doses of PCV7 in the second year of life or two doses in the second and two or three in the first year of life. A further two children were nonresponsive to a serotype (6B) different than that causing disease. None of the 10 children had a clinical risk factor for IPD. Two had marginally low levels of total serum IgG but mounted adequate responses to the other six PCV serotypes. This serotype-specific unresponsiveness may reflect immune paralysis due to large pneumococcal polysaccharide antigen loads and/or a potential genetic basis for nonresponse to individual pneumococcal serotypes.
The
Cryptococcus neoformans
Rho-GDP Dissociation Inhibitor Mediates Intracellular Survival and Virulence
Authors: Price Michael S. , Nichols Connie B. , Alspaugh J. Andrew
Published: September 2008

Rho-GDP dissociation inhibitors (Rho-GDI) are repressors of Rho-type monomeric GTPases that control fundamental cellular processes, such as cytoskeletal arrangement, vesicle trafficking, and polarized growth. We identified and altered the expression of the gene encoding a Rho-GDI homolog in the human fungal pathogen
Cryptococcus neoformans
and investigated its impact on pathogenicity in animal models of cryptococcosis. Consistent with its predicted function to inhibit and sequester Rho-type GTPases, overexpression of
RDI1
results in cytosolic localization of Cdc42. Likely as a result of this finding,
RDI1
-overexpressing strains exhibited altered morphology compared to that of the wild type, with apparent defects in maintaining proper cell polarity and cytokinesis.
RDI1
deletion resulted in increased vacuole size in tissue culture medium and aberrant cell morphology at neutral pH. Maintenance of normal cell morphology is vital for
C. neoformans
pathogenicity. Accordingly, the
rdi1
Δ mutant strain also showed reduced intracellular survival in macrophages and severe attenuation of virulence in two murine models of cryptococcosis. This reduction in virulence of the
rdi1
Δ mutant occurs in the absence of major growth defects in rich medium and with classical virulence-associated phenotypes.
Recruitment of Rab27a to Phagosomes Controls Microbial Antigen Cross-Presentation by Dendritic Cells
Authors: Kim Seong Hyun , Visser Annelies , Cruijsen Carin , van der Velden Adrianus W. M. , Boes Marianne
Published: September 2008

Polyreactive immunoglobulins (Ig) and complement components are present in tissues and blood of healthy individuals. They facilitate pathogen uptake and inactivation in lysosomes of phagocytes and thereby provide rapid protection against infection. Dendritic cells (DCs) are phagocytes that can acquire peptides from phagocytosed antigen to elicit cytotoxic immune responses by CD8+T lymphocytes. The mechanisms that select peptides for cross-presentation are not fully resolved. Here we investigated the role of polyreactive Ig and complement in directing phagosomal antigen processing for cross-presentation. Phagocytosis facilitated by serum opsonization required the presence of Ig for effective antigen cross-presentation of microbe-derived antigen. The presence of complement C3 in serum promoted phagocytosis, yet phagosomes were defective in antigen degradation. The small GTPase Rab27a was recently implicated in antigen cross-presentation and was rapidly recruited to phagosomes only when Ig was present. Our data suggest that prebinding of antigen by polyreactive Ig potentiates the efficiency of antigen cross-presentation to CD8+T cells through recruitment of Rab27a.
The effect of head protection on the hearing of rugby players: Table 1
Authors: Kieran S M , Dunne J , Hughes J P , Fenton J E
Published: September 2008

Objective:

Professional rugby players utilise various methods of head protection to prevent against the development of a pinna haematoma. This study tests the hypothesis that these measures, whilst preventing injury, decrease the wearers’ hearing threshold and therefore their performance.

Design and participants:

Eight patients had free field audiometry performed in a soundproof room, with warble tones. All patients were young men (mean 24.75 years (range 22–34)). No participant had ear symptomatology or a past history of ear surgery. Three separate audiological assessments were performed on each patient: normal free field audiometry in a sound field room, following application of adhesive tape and whilst wearing a scrum cap. All measurements were performed by a single audiological scientist. A significant clinical drop in hearing threshold was defined as an increase of 10 dB.

Results:

No patient demonstrated a significant drop in hearing threshold following the application of either tape or a scrum cap, nor was there a significant difference in the mean (SD) warble tone average: air 7.03 (5.47); tape 7.19 (6.40); scrum cap 6.56 (5.58).

Conclusion:

Theoretical concerns that “ear taping” and scrum caps affect hearing of rugby players are unfounded and should not discourage their use.
INFRARED SPECTRAL SIGNATURES: CREATION OF REFERENCE DATA FOR VAPORS AND LIQUIDS
Authors: SHARPE STEVEN , JOHNSON TIMOTHY , SAMS ROBERT , HYLDEN JEFFREY , KLEIMEYER JAMES , ROWLAND BRAD
Published: September 2008

Two primary goals of infrared spectroscopic detection are chemical identification and quantification. In order to accomplish these goals, a comprehensive and quantitative spectral library suitable for digital manipulation is required. To a large degree, the contents of such a library depend on the application. Since the primary application of the PNNL/DOE spectral library is for environmental monitoring, we have focused our efforts on hazardous pollutants, as well as a large variety of natural and anthropogenic chemicals. As a spin-off project and in collaboration with Dugway Proving Ground, we also had the opportunity to analyze a limited set of chemical warfare agents (CWAs). An example of such data appears below. [Formula: see text]

Infrared optical properties of VX [O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate] in the vapor and liquid phases. Refractive index data (top traces) are critical for modeling aerosol and reflection phenomena.
PASSIVE STANDOFF DETECTION OF SURFACE CONTAMINANTS: A NOVEL APPROACH BY DIFFERENTIAL POLARIZATION FTIR SPECTROMETRY
Authors: THÉRIAULT JEAN-MARC , LAVOIE HUGO , PUCKRIN ELDON , BOUFFARD FRANCOIS
Published: September 2008

An approach for the passive standoff detection of surface contaminants by differential polarization FTIR spectrometry is proposed. The surface radiance modeling associated with the method is given. Unpolarized and polarized sensing measurements obtained with the CATSI sensor for the standoff detection of liquid agent VX deposited on high-reflectivity surfaces are presented. The analysis of results indicates that the differential polarization approach is well suited to mitigate sky radiance drifts, which favours unambiguous surface contaminant detections. An experimental and modeling study initiated to address the spectral polarization phenomenology is outlined. The design of an optimized FTIR sensor for differential polarization spectrometry measurements is discussed.
BACKGROUND CONTRIBUTIONS IN DIRECT AND DIFFERENTIAL FOURIER TRANSFORM LWIR MEASUREMENTS: A COMPARATIVE ANALYSIS
Authors: BOUFFARD FRANÇOIS , THÉRIAULT JEAN-MARC
Published: September 2008

In order to assess the differences between background clutter using the CATSI instrument in direct (single-beam) and differential (double-beam) mode, a survey of background measurements was undertaken. Measurements include samples of sky, mountains, forest, buildings, roads and snow during springtime in the long wave infrared using both single-beam and double-beam interferometry. It is found that background distribution and statistics in these two modes are significantly different, with the differential mode presenting less variation than the direct mode. This may impact the ability to detect atmospheric contaminants. This analysis was performed in order to better understand the difference between operating a standard and a differential FTIR instrument.
NOVEL APPLICATION OF PASSIVE STANDOFF RADIOMETRY FOR THE MEASUREMENT OF EXPLOSIVES
Authors: PUCKRIN ELDON , THÉRIAULT JEAN-MARC , LAVOIE HUGO , DUBÉ DENIS , BROUSSEAU PATRICK
Published: September 2008

The objective of this paper is to show that explosives may potentially be detected by passive standoff FTIR radiometry. It is demonstrated that many explosives exhibit a signature (fingerprint) in the longwave infrared (LWIR) region (i.e., 8 – 14 μm). Simulations using the radiative transfer model, MODTRAN4, clearly suggest that such materials can be identified when a thermal contrast exists between the material and its environment. The explosives considered in this study include octogen (HMX), trinitrotoluene (TNT), cyclonite (RDX), and the plastic explosives, C-4 and Detasheet-C. In addition, passive FTIR measurements of HMX have been performed in the field at standoff distances up to 60 m. The development of a passive standoff detection capability based on FTIR radiometry may be a potentially useful addition to the arsenal of measurement techniques that currently exist for the detection and identification of explosive threats.
DETECTION AND CLASSIFICATION OF ORGANIC AND ORGANOPHOSPHORUS ANALYTES ON SOIL FROM REFLECTION-ABSORPTION SPECTROSCOPY
Authors: BLAKE THOMAS A. , GASSMAN PAUL L. , GALLAGHER NEAL B.
Published: September 2008

Principal Components Analysis (PCA) is a common anomaly detection tool that was used in this work to detect organic and organophosphate analytes on soils using mid-infrared reflection-absorption spectroscopy. Detection is hindered by large variability in sample-to-sample soil reflectivity that is due to the random nature of the soil particle packing. Extended multiplicative scatter correction (EMSC) and Savitzky-Golay derivative preprocessing were examined as methods to reduce this variability and enhance detection capability. Second derivative preprocessing provided results that were at least as good as EMSC for detection and the simplicity of the derivative methodology makes it an attractive preprocessing approach. Typically, PCA is applied to all spectral channels and results from detection events are interrogated to identify a potential cause. In this work, PCA models were developed for specific wavenumber ranges corresponding to functional group frequencies with the objective of providing some classification capability. It was found that detection of CH 2, CH 3 and P = O stretching bands was possible; however, results for a – CH 2 scissors band was less encouraging and detection of O – H stretch, – C – C – skeletal stretch, and PO – C stretch modes was poor. Some limited classification capability may be possible, but it would be difficult to make a unique assignment of the analytes present using the strategies studied.
SOME EFFECTS OF IMAGE SEGMENTATION ON SUBSPACE-BASED AND COVARIANCE-BASED DETECTION OF ANOMALOUS SUB-PIXEL MATERIALS
Authors: GITTINS CHRISTOPHER , KONNO DAISEI , HOKE MICHAEL , RATKOWSKI ANTHONY
Published: September 2008

In this paper we assess the effect that clustering pixels into spectrally-similar background types, for example, soil, vegetation, and water in hyperspectral visible/near-IR/SWIR imagery, prior to applying a detection methodology has on material detection statistics. Specifically, we examine the effects of data segmentation on two statistically-based detection metrics, the Subspace Generalized Likelihood Ratio Test (Subspace GLRT) and the Adaptive Cosine Estimator (ACE), applied to a publicly-available AVIRIS datacube augmented with a synthetic material spectrum in selected pixels. The use of synthetic spectrum-augmented data enables quantitative comparison of Subspace-GLRT and ACE using Receiver Operating Characteristic (ROC) curves. For all cases investigated, Receiver Operating Characteristic (ROC) curves generated using ACE were as good as or superior to those generated using Subspace-GLRT. The favorability of ACE over Subspace-GLRT was more pronounced as the synthetic spectrum mixing fraction decreased. For probabilities of detection in the range of 50-80%, segmentation reduced the probability of false alarm by a factor of 3–5 when using ACE. In contrast, segmentation had no apparent effect on detection statistics using Subspace-GLRT, in this example.
EYESAFE ACTIVE IMAGING OF HARD TARGETS: AN OVERVIEW OF TECHNIQUES UNDER INVESTIGATION BY NVESD
Authors: SCHILLING BRADLEY W. , CHINN STEPHEN R. , THOMAS BRIAN , SCHOLZ TIMOTHY J.
Published: September 2008

The U.S. Army is actively pursuing 3D active imaging techniques using laser sources emitting at 1.5 μm. This eyesafe short wave infrared (SWIR) waveband is advantageous due to both the improved eye safety and atmospheric propagation through obscurants. NVESD has several active programs in this area, which will be reviewed in this paper. These are: 1) single-pixel scanned imaging laser radar, 2) 2D gated SWIR imaging, and 3) 3D-flash laser radar. These systems are being evaluated for various targeting scenarios, including as potential payloads on unmanned air-vehicles, ground vehicles and other sensor suites. Applications include low-cost long-range target identification, identification of heavily obscured targets, obstacle avoidance, and high resolution imaging.
DETECTION AND DIFFERENTIATION OF SPORE AND VEGETATIVE FORMS OF BACILLUS SPP. USING INFRARED SPECTROSCOPIC METHODS
Authors: AMANT DIANE ST. , CAMPBELL MARK , BECK ANDREW , WILLIAMS LESLIE , MINTER JENNIFER , COLLETT PATRICIA , ZHU CHANGJIANG , SAMUELS ALAN
Published: September 2008

Infrared spectroscopy has been demonstrated as a powerful tool for taxonomic classification of bacteria when the microbes are grown and sampled under carefully controlled conditions. Infrared spectroscopy affords limited information about relative proportions of certain chemical functional groups in whole microbial cells. The objective of this work is to elucidate the ability of infrared spectroscopy to identify and speciate Bacillus spp. regardless of sample history. Spectrometers utilize different scanning methods to collect infrared absorption spectra. We employed three; transmission through a thin film, transmission infrared microscopy, and Attenuated Total Reflection (ATR). Target organisms include Bacillus anthracis, and several near neighbors. Each strain was cultured at 24°C and 35°C on three solid media. Microorganisms were incubated for up to ten days to include vegetative cells, spore formation and mature spores. Triplicate microbe samples were prepared and analyzed according to instrument requirements using the three measurement modes. Triplicate samples of BSL-3 organisms were analyzed only by the thin film transmission method. Spectral data was analyzed using the cluster analysis function of OPUS software. We report that infrared spectrometry is capable of discerning Bacillus spores from vegetative cells and the phylogenic clustering of Bacillus species according to pathogenicity levels via infrared spectral analysis.
SPECTRAL PROCESSING OF LASER-INDUCED FLUORESCENCE FROM THREATENING BIOLOGICAL AEROSOLS
Authors: LAHAIE PIERRE , SIMARD J. R. , MCFEE J. , BUTEAU S. , HO J. , MATHIEU P. , ROY G. , LAROCHELLE V.
Published: September 2008

The stand-off detection classification by laser induced fluorescence is the objective of the Biosense project. The sensor will perform the monitoring of a defined area around its location using an elastic lidar detector for particles cloud. The detection of cloud will trigger fluorescence probing of the cloud. To perform this task the area fluorescence background will be monitored in order to evaluate if a return signal changed. Using a simple signal model built with experimental data, we designed a detection and monitoring procedure for the fluorescence at a single location. Signal simulations have been performed to verify the operation of the system. The results of the simulation indicate the system is able to detect anomaly with small contrast between a signal and the background. The results will have to be extended to area surveillance and a more complete signal model for various environments in natural conditions is required
STANDOFF DETERMINATION OF BIOAEROSOL SIZE BASED ON DOUBLE SCATTERING MEASUREMENT WITH MFOV LIDAR: CONCEPT AND NUMERICAL SIMULATION
Authors: ROY GILLES , BISSONNETTE LUC R.
Published: September 2008

We investigate the use of multiple scattering via Multiple-Field-Of-View (MFOV) lidar signals to characterize bioaerosol particles size and concentration from ground based lidar over distances shorter than a few kilometers. The MFOV lidar signal is calculated for background aerosols at a wavelength 355 nm for a visibility of 30 km. The optical depths studied are small and the calculations are restricted to second order scattering. Also since background aerosols are constituted of relatively small particles which diffuse the light at large angles, the fields of view (FOV) range from 1 to 100 mrad full angle. We show that the MFOV lidar measurements contain exploitable information on particle size and extinction.
A PYRAMID-BASED BLOCK OF SKEWERS FOR PIXEL PURITY INDEX FOR ENDMEMBER EXTRACTION IN HYPERSPECTRAL IMAGERY
Authors: CHANG CHEIN-I , HSUEH MINGKAI , LIU WEIMIN , WU CHAO-CHENG , CHAUDHRY FARZEEN , SOLYAR GREGORY , PLAZA ANTONIO
Published: September 2008

Pixel Purity Index (PPI) has been widely used for endmember extraction. Recently, an approach using blocks of skewers was proposed by Theiler et al., called blocks of skewers (BOS) method, to improve computation of the PPI. It utilizes a block of skewers to reduce number of calculations of dot products operated by the PPI on each skewers with all data sample vectors. Unfortunately, the BOS method also suffers from the same drawbacks that the PPI does in terms of several parameters which are needed to be determined a priori. Besides, it also has an additional parameter, block size, B needed to be determined where no guideline is provided of how to select this parameter. In this paper, the BOS method is also investigated. Most importantly, a new pyramid-based block design for the BOS method is also introduced as opposed to the cube-based block designed used by Theiler et al.'s BOS. One major advantage of our proposed pyramid-based BOS over Theiler et al.'s cube-design BOS is the hardware design for Field Programmable Gate Arrays (FPGAs) implementation.
Undirected connectivity in log-space
Authors: Reingold Omer
Published: September 2008

We present a
deterministic
, log-space algorithm that solves st-connectivity in undirected graphs. The previous bound on the space complexity of undirected st-connectivity was log
4/3
(⋅) obtained by Armoni, Ta-Shma, Wigderson and Zhou (JACM 2000). As undirected st-connectivity is complete for the class of problems solvable by symmetric, nondeterministic, log-space computations (the class SL), this algorithm implies that SL = L (where L is the class of problems solvable by deterministic log-space computations). Independent of our work (and using different techniques), Trifonov (STOC 2005) has presented an
O
(log
n
log log
n
)-space, deterministic algorithm for undirected st-connectivity.

Our algorithm also implies a way to construct in log-space a
fixed
sequence of directions that guides a deterministic walk through all of the vertices of any connected graph. Specifically, we give log-space constructible universal-traversal sequences for graphs with restricted labeling and log-space constructible universal-exploration sequences for general graphs.
Semantic subtyping
Authors: Frisch Alain , Castagna Giuseppe , Benzaken Véronique
Published: September 2008

Subtyping relations are usually defined either syntactically by a formal system or semantically by an interpretation of types into an untyped denotational model. This work shows how to define a subtyping relation semantically in the presence of Boolean connectives, functional types and dynamic dispatch on types, without the complexity of denotational models, and how to derive a complete subtyping algorithm.
Time course of high-fat diet-induced reductions in adipose tissue mitochondrial proteins: potential mechanisms and the relationship to glucose intolerance
Authors: Sutherland Lindsey N. , Capozzi Lauren C. , Turchinsky N. Joan , Bell Rhonda C. , Wright David C.
Published: September 2008

Increasing evidence suggests that reduced adipose tissue mitochondrial content is associated with the pathogenesis of type 2 diabetes. These investigations have utilized severely insulin-resistant rodent models. Thus, it is difficult to ascertain the potential mechanisms that initiate these changes and whether reductions in adipose mitochondria are an initiating event in the development of impaired glucose homeostasis. Thus, we sought to determine the time course of high-fat diet-induced reductions of mitochondrial content in epididymal adipose tissue in relation to changes in purported mediators of mitochondrial biogenesis and the development of impaired glucose homeostasis. Male Wistar rats were fed a high-fat diet (∼59% of kcals from fat) for 2, 4, or 6 wk. Six weeks of high-fat feeding resulted in reductions in CORE I, COX IV, cytochrome c, HSP60, relative mtDNA copy number, and PGC-1α expression. These changes were not associated with decreases in eNOS and AMPK or increases in markers of oxidative stress. Interestingly, ex vivo treatment of adipose tissue cultures with palmitate led to decreases in PGC-1α expression and COX IV and CORE I protein content as observed in vivo. Thus, the high-fat diet-induced reductions in adipose tissue mitochondrial proteins may be mediated by increases in plasma fatty acids. Importantly, reductions in adipose tissue mitochondrial content occurred after the development of impaired glucose homeostasis. Thus, reductions in adipose tissue mitochondrial proteins are most likely not a causal event in the development of impaired glucose homeostasis.
TZDs and Bone: A Review of the Recent Clinical Evidence
Authors: Schwartz Ann V.
Published: September 2008

Over the past two years, evidence has emerged that the currently available thiazolidinediones (TZDs), rosiglitazone, and pioglitazone have negative skeletal consequences, at least in women, which are clinically important. Increased fracture risk in women, but not men, was reported for both TZDs, based on analyses of adverse event reports from clinical trials. In short‐term clinical trials in women, both TZDs caused more rapid bone loss. In these trials, changes in bone turnover markers suggest a pattern of reduced bone formation without a change in resorption. Although limited, these results support the hypothesis based on rodent and in vitro models that reduced bone formation resulting from activation of peroxisome proliferator‐activated receptor‐γ (PPARγ) is a central mechanism for TZDs_ effect on bone. Research is needed to better understand the mechanisms of bone loss with TZDs, to identify factors that influence susceptibility to TZD‐induced osteoporosis, and to test treatments for its prevention.
Coesite Formation at Ambient Pressure and Low Temperatures
Authors: Martínez J. R. , Vázquez-Durán A. , Martínez-Castañón G. , Ortega-Zarzosa G. , Palomares-Sánchez S. A. , Ruiz Facundo
Published: September 2008

Partial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that partial crystallization of the glass matrix in the form of coestite was obtained at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The presence of coesite is corroborated by the Rietveld refinement method.
An Anisotropic Constitutive Equation for the Stress Tensor of Blood Based on Mixture Theory
Authors: Massoudi Mehrdad , Antaki James F.
Published: September 2008

Based on ideas proposed by Massoudi and Rajagopal (M‐R), we develop a model for blood using the theory of interacting continua, that is, the mixture theory. We first provide a brief review of mixture theory, and then discuss certain issues in constitutive modeling of a two‐component mixture. In the present formulation, we ignore the biochemistry of blood and assume that blood is composed of red blood cells (RBCs) suspended in plasma, where the plasma behaves as a linearly viscous fluid and the RBCs are modeled as an anisotropic nonlinear density‐gradient‐type fluid. We obtain a constitutive relation for blood, based on the simplified constitutive relations derived for plasma and RBCs. A simple shear flow is discussed, and an exact solution is obtained for a very special case; for more general cases, it is necessary to solve the nonlinear coupled equations numerically.
Some Extensions of Banach's Contraction Principle in Complete Cone Metric Spaces
Authors: Raja P. , Vaezpour S. M.
Published: September 2008

In this paper we consider complete cone metric spaces. We generalize some definitions such as "Equation missing"-nonexpansive and "Equation missing"-uniformly locally contractive functions "Equation missing"-closure, "Equation missing"-isometric in cone metric spaces, and certain fixed point theorems will be proved in those spaces. Among other results, we prove some interesting applications for the fixed point theorems in cone metric spaces.
Context-Aware UPnP-AV Services for Adaptive Home Multimedia Systems
Authors: Tusch Roland , Jakab Michael , Köpke Julius , Krätschmer Armin , Kropfberger Michael , Kuchler Sigrid , Ofner Michael , Hellwagner Hermann , Böszörmenyi Laszlo
Published: September 2008

One possibility to provide mobile multimedia in domestic multimedia systems is the use of Universal Plug and Play Audio Visual (UPnP-AV) devices. In a standard UPnP-AV scenario, multimedia content provided by a Media Server device is streamed to Media Renderer devices by the initiation of a Control Point. However, there is no provisioning of context-aware multimedia content customization. This paper presents an enhancement of standard UPnP-AV services for home multimedia environments regarding context awareness. It comes up with context profile definitions, shows how this context information can be queried from the Media Renderers, and illustrates how a Control Point can use this information to tailor a media stream from the Media Server to one or more Media Renderers. Moreover, since a standard Control Point implementation only queries one Media Server at a time, there is no global view on the content of all Media Servers in the UPnP-AV network. This paper also presents an approach of multimedia content integration on the Media Server side that provides fast search for content on the network. Finally, a number of performance measurements show the overhead costs of our enhancements to UPnP-AV in order to achieve the benefits.
Quasicontraction Mappings in Modular Spaces without Δ2-Condition
Authors: Khamsi M.A.
Published: September 2008

As a generalization to Banach contraction principle, Ćirić introduced the concept of quasi-contraction mappings. In this paper, we investigate these kinds of mappings in modular function spaces without the "Equation missing"2-condition. In particular, we prove the existence of fixed points and discuss their uniqueness.