bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing radiation dose to selected organs by selecting the tube start angle in MDCT helical scans: A Monte Carlo based study
Authors: Zhang Di , Zankl Maria , DeMarco John J. , Cagnon Chris H. , Angel Erin , Turner Adam C. , McNitt‐Gray Michael F.
Published: November 2009

Purpose:

Previous work has demonstrated that there are significant dose variations with a sinusoidal pattern on the peripheral of a CTDI 32 cm phantom or on the surface of an anthropomorphic phantom when helical CT scanning is performed, resulting in the creation of “hot” spots or “cold” spots. The purpose of this work was to perform preliminary investigations into the feasibility of exploiting these variations to reduce dose to selected radiosensitive organs solely by varying the tube start angle in CT scans.

Methods:

Radiation dose to several radiosensitive organs (including breasts, thyroid, uterus, gonads, and eye lenses) resulting from MDCT scans were estimated using Monte Carlo simulation methods on voxelized patient models, including GSF's Baby, Child, and Irene. Dose to fetus was also estimated using four pregnant female models based on CT images of the pregnant patients. Whole‐body scans were simulated using 120 kVp, 300 mAs, both 28.8 and 40 mm nominal collimations, and pitch values of 1.5, 1.0, and 0.75 under a wide range of start angles (0°–340° in 20° increments). The relationship between tube start angle and organ dose was examined for each organ, and the potential dose reduction was calculated.

Results:

Some organs exhibit a strong dose variation, depending on the tube start angle. For small peripheral organs (e.g., the eye lenses of the Baby phantom at pitch 1.5 with 40 mm collimation), the minimum dose can be 41% lower than the maximum dose, depending on the tube start angle. In general, larger dose reductions occur for smaller peripheral organs in smaller patients when wider collimation is used. Pitch 1.5 and pitch 0.75 have different mechanisms of dose reduction. For pitch 1.5 scans, the dose is usually lowest when the tube start angle is such that the x‐ray tube is posterior to the patient when it passes the longitudinal location of the organ. For pitch 0.75 scans, the dose is lowest when the tube start angle is such that the x‐ray tube is anterior to the patient when it passes the longitudinal location of the organ.

Conclusions:

Helical MDCT scanning at pitch 1.5 and pitch 0.75 results in “cold spots” and “hot spots” that are created both at surface and in‐depth locations within patients. For organs that have a relatively small longitudinal extent, dose can vary considerably with different start angles. While current MDCT systems do not provide the user with the ability to control the tube start angle, these results indicate that in these specific situations (pitch 1.5 or pitch 0.75, small organs and especially small patients), there could be significant dose savings to organs if that functionality would be provided.
Ca
2+
Puffs Originate from Preestablished Stable Clusters of Inositol Trisphosphate Receptors
Authors: Smith Ian F. , Wiltgen Steven M. , Shuai Jianwei , Parker Ian
Published: November 2009

Localized calcium signals called Ca
2+
puffs arise at preestablished clusters of IP
3
Rs.
Eukaryotic Protein Domains as Functional Units of Cellular Evolution
Authors: Jin Jing , Xie Xueying , Chen Chen , Park Jin Gyoon , Stark Chris , James D. Andrew , Olhovsky Marina , Linding Rune , Mao Yongyi , Pawson Tony
Published: November 2009

Clustering proteins into groups on the basis of their domain compositions provides insight into protein evolution.
Regulatory Neutrophils
Authors: Foley John F.
Published: November 2009

Syk- and MyD88-dependent signaling pathways converge to endow mouse neutrophils with regulatory properties.
Periplasmic Redox Regulation
Authors: Hurtley Stella M.
Published: November 2009

A thioredoxin-like enzyme controls the oxidation state of the bacterial periplasm.
Maintaining Diplomatic Relations Between Mammals and Beneficial Microbial Communities
Authors: Hill David A. , Artis David
Published: November 2009

The adaptive immune system compensates if innate mechanisms fail to contain microbes in the mammalian intestine.
SCY-635, a Novel Nonimmunosuppressive Analog of Cyclosporine That Exhibits Potent Inhibition of Hepatitis C Virus RNA ReplicationIn Vitro
Authors: Hopkins Sam , Scorneaux Bernard , Huang Zhuhui , Murray Michael G. , Wring Stephen , Smitley Craig , Harris Richard , Erdmann Frank , Fischer Gunter , Ribeill Yves
Published: November 2009

SCY-635 is a novel nonimmunosuppressive cyclosporine-based analog that exhibits potent suppression of hepatitis C virus (HCV) replicationin vitro. SCY-635 inhibited the peptidyl prolyl isomerase activity of cyclophilin A at nanomolar concentrations but showed no detectable inhibition of calcineurin phosphatase activity at concentrations up to 2 μM. Metabolic studies indicated that SCY-635 did not induce the major cytochrome P450 enzymes 1A2, 2B6, and 3A4. SCY-635 was a weak inhibitor and a poor substrate for P-glycoprotein. Functional assays with stimulated Jurkat cells and stimulated human peripheral blood mononuclear cells indicated that SCY-635 is a weaker inhibitor of interleukin-2 secretion than cyclosporine. A series of two-drug combination studies was performedin vitro. SCY-635 exhibited synergistic antiviral activity with alpha interferon 2b and additive antiviral activity with ribavirin. SCY-635 was shown to be orally bioavailable in multiple animal species and produced blood and liver concentrations of parent drug that exceeded the 50% effective dose determined in the bicistronic con1b-derived replicon assay. These results suggest that SCY-635 warrants further investigation as a novel therapeutic agent for the treatment of individuals who are chronically infected with HCV.
Activity of a New Antipseudomonal Cephalosporin, CXA-101 (FR264205), against Carbapenem-Resistant and Multidrug-Resistant
Pseudomonas aeruginosa
Clinical Strains
Authors: Juan Carlos , Zamorano Laura , Pérez José L. , Ge Yigong , Oliver Antonio
Published: November 2009

The activity of the new cephalosporin CXA-101 (CXA), previously designated FR264205, was evaluated against a collection of 236 carbapenem-resistant
P. aeruginosa
isolates, including 165 different clonal types, from a Spanish multicenter (127-hospital) study. The MICs of CXA were compared to the susceptibility results for antipseudomonal penicillins, cephalosporins, carbapenems, aminoglycosides, and fluoroquinolones. The MIC of CXA in combination with tazobactam (4 and 8 μg/ml) was determined for strains with high CXA MICs. The presence of acquired β-lactamases was investigated by isoelectric focusing and PCR amplification followed by sequencing. Additional β-lactamase genes were identified by cloning and sequencing. The CXA MIC
50
/MIC
90
for the complete collection of carbapenem-resistant
P. aeruginosa
isolates was 1/4 μg/ml, with 95.3% of the isolates showing an MIC of ≤8 μg/ml. Cross-resistance with any of the antibiotics tested was not observed; the MIC
50
/MIC
90
of CXA-101 was still 1/4 when multidrug-resistant (MDR) strains (42% of all tested isolates) or AmpC-hyperproducing clones (53%) were analyzed. Almost all (10/11) of the strains showing a CXA MIC of >8 μg/ml produced a horizontally acquired β-lactamase, including the metallo-β-lactamase (MBL) VIM-2 (one strain), the extended-spectrum β-lactamase (ESBL) PER-1 (one strain), several extended-spectrum OXA enzymes (OXA-101 [one strain], OXA-17 [two strains], and a newly described OXA-2 derivative [W159R] designated OXA-144 [four strains]), and a new BEL variant (BEL-3) ESBL (one strain), as identified by cloning and sequencing. Synergy with tazobactam in these 11 strains was limited, although 8 μg/ml reduced the mean CXA MIC by 2-fold. CXA is highly active against carbapenem-resistant
P. aeruginosa
isolates, including MDR strains. Resistance was restricted to still-uncommon strains producing an acquired MBL or ESBL.
Pharmacokinetics of Ertapenem following Intravenous and Subcutaneous Infusions in Patients
Authors: Frasca Denis , Marchand Sandrine , Petitpas Franck , Dahyot-Fizelier Claire , Couet William , Mimoz Olivier
Published: November 2009

Steady-state pharmacokinetics of ertapenem were compared in patients after 1-g intravenous and subcutaneous (s.c.) infusions. Bioavailability was 99% ± 18% after s.c. administration, but peaks were reduced by about (43 ± 29 versus 115 ± 28 μg/ml) and times to peak were delayed. Simulations based on unbound concentrations show that time over the MIC should always be longer than 30% to 40% of the dosing interval, suggesting that s.c. infusion could be an alternative in patients with reduced vascular access.
Activity and Toxicity of Farnesol towards
Candida albicans
Are Dependent on Growth Conditions
Authors: Langford Melanie L. , Hasim Sahar , Nickerson Kenneth W. , Atkin Audrey L.
Published: November 2009

Farnesol interacts with
Candida albicans
as both a quorum-sensing molecule and toxic agent, but confusion abounds regarding which conditions promote these distinct responses. Farnesol sensitivity was measured when inoculum cell history and size, temperature, and growth media were altered. Parameters for farnesol tolerance/sensitivity were defined, validating previous studies and identifying new variables, such as energy availability. This study clearly defines what farnesol concentrations are lethal to
C. albicans
, based on environmental conditions.
Campylobacter jejuni
and
Campylobacter coli
Genotyping by High-Resolution Melting Analysis of a
flaA
Fragment
Authors: Merchant-Patel Shreema , Blackall Patrick J. , Templeton Jillian , Price Erin P. , Tong Steven Y. C. , Huygens Flavia , Giffard Philip M.
Published: November 2009

The highly variable flagellin-encoding
flaA
gene has long been used for genotyping
Campylobacter jejuni
and
Campylobacter coli
. High-resolution melting (HRM) analysis is emerging as an efficient and robust method for discriminating DNA sequence variants. The objective of this study was to apply HRM analysis to
flaA
-based genotyping. The initial aim was to identify a suitable
flaA
fragment. It was found that the PCR primers commonly used to amplify the
flaA
short variable repeat (SVR) yielded a mixed PCR product unsuitable for HRM analysis. However, a PCR primer set composed of the upstream primer used to amplify the fragment used for
flaA
restriction fragment length polymorphism (RFLP) analysis and the downstream primer used for
flaA
SVR amplification generated a very pure PCR product, and this primer set was used for the remainder of the study. Eighty-seven
C. jejuni
and 15
C. coli
isolates were analyzed by
flaA
HRM and also partial
flaA
sequencing. There were 47
flaA
sequence variants, and all were resolved by HRM analysis. The isolates used had previously also been genotyped using single-nucleotide polymorphisms (SNPs), binary markers, CRISPR HRM, and
flaA
RFLP.
flaA
HRM analysis provided resolving power multiplicative to the SNPs, binary markers, and CRISPR HRM and largely concordant with the
flaA
RFLP. It was concluded that HRM analysis is a promising approach to genotyping based on highly variable genes.
Effectiveness of Liquid Soap and Hand Sanitizer against Norwalk Virus on Contaminated Hands
Authors: Liu Pengbo , Yuen Yvonne , Hsiao Hui-Mien , Jaykus Lee-Ann , Moe Christine
Published: November 2009

Disinfection is an essential measure for interrupting human norovirus (HuNoV) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. The purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against Norwalk virus (NV) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of NV on human finger pads. Samples were tested by real-time reverse transcription-quantitative PCR (RT-qPCR) both with and without a prior RNase treatment. In suspension assay, sodium hypochlorite concentrations of ≥160 ppm effectively eliminated RT-qPCR detection signal, while ethanol, regardless of concentration, was relatively ineffective, giving at most a 0.5 log
10
reduction in genomic copies of NV cDNA. Using the American Society for Testing and Materials (ASTM) standard finger pad method and a modification thereof (with rubbing), we observed the greatest reduction in genomic copies of NV cDNA with the antibacterial liquid soap treatment (0.67 to 1.20 log
10
reduction) and water rinse only (0.58 to 1.58 log
10
reduction). The alcohol-based hand sanitizer was relatively ineffective, reducing the genomic copies of NV cDNA by only 0.14 to 0.34 log
10
compared to baseline. Although the concentrations of genomic copies of NV cDNA were consistently lower on finger pad eluates pretreated with RNase compared to those without prior RNase treatment, these differences were not statistically significant. Despite the promise of alcohol-based sanitizers for the control of pathogen transmission, they may be relatively ineffective against the HuNoV, reinforcing the need to develop and evaluate new products against this important group of viruses.
Effects of Technological Processes on the Tenacity and Inactivation of Norovirus Genogroup II in Experimentally Contaminated Foods
Authors: Mormann Sascha , Dabisch Mareike , Becker Barbara
Published: November 2009

Contaminated food is a significant vehicle for human norovirus transmission. The present study determined the effect of physicochemical treatments on the tenacity of infective human norovirus genogroup II in selected foods. Artificially contaminated produce was subjected to a number of processes used by the food industry for preservation and by the consumer for storage and preparation. Virus recovery was carried out by using ultrafiltration and was monitored by using bacteriophage MS2 as an internal process control. Norovirus was quantified by using monoplex one-step TaqMan real-time reverse transcription (RT)-PCR and an external standard curve based on recombinant RNA standards. An RNase pretreatment step was used to avoid false-positive PCR results caused by accessible RNA, which allowed detection of intact virus particles. Significant reductions in titers were obtained with heat treatments usually applied by consumers for food preparation (baking, cooking, roasting). Generally, processes used for preservation and storage, such as cooling, freezing, acidification (≥pH 4.5), and moderate heat treatments (pasteurization), appear to be insufficient to inactivate norovirus within a food matrix or on the surface of food. Besides data for persistence in processed food, comparable data for individual matrix-specific protective effects, recovery rates, and inhibitory effects on the PCRs were obtained in this study. The established procedure might be used for other noncultivable enteric RNA viruses that are connected to food-borne diseases. The data obtained in this study may also help optimize the process for inactivation of norovirus in food by adjusting food processing technologies and may promote the development of risk assessment systems in order to improve consumer protection.
Construction of a Nontoxigenic
Clostridium botulinum
Strain for Food Challenge Studies
Authors: Bradshaw Marite , Marshall Kristin M. , Heap John T. , Tepp William H. , Minton Nigel P. , Johnson Eric A.
Published: November 2009

Clostridium botulinum
produces the most poisonous natural toxin known and is a perennial concern to the food industry and to regulatory agencies due to the potential threat of food-borne botulism. To ensure the botulinal safety of foods, rigorous food challenge testing to validate food-processing conditions and food formulations has been routinely performed. Detection of the botulinum neurotoxin is performed by using a mouse bioassay and/or
in vitro
assays. There has been considerable interest by the food industry and regulatory agencies in minimizing or even replacing the use of animals in these challenge studies. In addition, due to stringent select-agent regulations, the testing of various foods using toxigenic
C. botulinum
strains requires facilities and personnel that are certified for work with this organism. For this purpose we propose to generate sets of nontoxigenic
C. botulinum
strains from proteolytic and nonproteolytic groups that differ from the wild-type strains only by their inability to produce botulinum neurotoxin. In this initial study we describe the generation of a nontoxigenic mutant of
C. botulinum
strain 62A using the ClosTron mutagenesis system by inserting a group II intron into the botulinum neurotoxin type A gene (
bont/A
). The mutant clones were nontoxigenic as determined by Western blots and mouse bioassays but showed physiological characteristics, including growth properties and sporulation, that were similar to those of the parent strain in laboratory media. Additional studies will be required to evaluate comparable characteristics in various food matrices. The availability of suitable nontoxigenic
C. botulinum
strains for food challenge studies will be beneficial for enhancing the botulinal safety of foods as well as increasing the biosafety of workers and may eliminate the use of laboratory animals.
Manure- and Biosolids-Resident Murine Norovirus 1 Attachment to and Internalization by Romaine Lettuce
Authors: Wei Jie , Jin Yan , Sims Tom , Kniel Kalmia E.
Published: November 2009

The attachment of murine norovirus 1 (MNV) in biosolids, swine manure, and dairy manure to Romaine lettuce and internalization of this virus were evaluated. The MNV in animal manures had behavior similar to that of pure MNV; however, MNV in biosolids had significantly higher levels of attachment and internalization than pure MNV or MNV in manures. The incubation time did not affect the attachment of MNV in biosolids or manure. Confocal microscopy was used to observe MNV on lettuce after SYBR gold-labeled MNV was added directly to lettuce or after lettuce was submersed in labeled virus. MNV was observed on the lettuce surface, inside open cuts, and occasionally within stomata. In general, lettuce pieces with a long cut on the edge and short cuts on the stem was more likely to contain internalized MNV than intact lettuce pieces, as observed by confocal microscopy; however, while the difference was visible, it was not statistically significant. This study showed that the presence of MNV in biosolids may increase the risk of fresh produce contamination and that the MNV in open cuts and stomata is likely to be protected from sanitization.
Conversion of Glycerol to Poly(3-Hydroxypropionate) in Recombinant
Escherichia coli
Authors: Andreeßen Björn , Lange Alvin Brian , Robenek Horst , Steinbüchel Alexander
Published: November 2009

We have developed the conversion of glycerol into thermoplastic poly(3-hydroxypropionate) [poly(3HP)]. For this, the genes for glycerol dehydratase (
dhaB1
) of
Clostridium butyricum
, propionaldehyde dehydrogenase (
pduP
) of
Salmonella enterica
serovar Typhimurium LT2, and polyhydroxyalkanoate (PHA) synthase (
phaC1
) of
Ralstonia eutropha
were expressed in recombinant
Escherichia coli
. Poly(3HP) was accumulated up to 11.98% (wt/wt [cell dry weight]) in a two-step, fed-batch fermentation. The present study shows an interesting application to engineer a poly(3HP) synthesis pathway in bacteria.
Toll-Like Receptor Stimulation Enhances Phagocytosis and Intracellular Killing of Nonencapsulated and EncapsulatedStreptococcus pneumoniaeby Murine Microglia
Authors: Ribes Sandra , Ebert Sandra , Regen Tommy , Agarwal Amit , Tauber Simone C. , Czesnik Dirk , Spreer Annette , Bunkowski Stephanie , Eiffert Helmut , Hanisch Uwe-Karsten , Hammerschmidt Sven , Nau Roland
Published: November 2009

Toll-like receptors (TLRs) are crucial pattern recognition receptors in innate immunity that are expressed in microglia, the resident macrophages of the brain. TLR2, -4, and -9 are important in the responses againstStreptococcus pneumoniae, the most common agent causing bacterial meningitis beyond the neonatal period. Murine microglial cultures were stimulated with agonists for TLR1/2 (Pam3CSK4), TLR4 (lipopolysaccharide), and TLR9 (CpG oligodeoxynucleotide) for 24 h and then exposed to either the encapsulated D39 (serotype 2) or the nonencapsulated R6 strain ofS. pneumoniae. After stimulation, the levels of interleukin-6 and CCL5 (RANTES [regulated upon activation normal T-cell expressed and secreted]) were increased, confirming microglial activation. The TLR1/2, -4, and -9 agonist-stimulated microglia ingested significantly more bacteria than unstimulated cells (P< 0.05). The presence of cytochalasin D, an inhibitor of actin polymerizaton, blocked >90% of phagocytosis. Along with an increased phagocytic activity, the intracellular bacterial killing was also increased in TLR-stimulated cells compared to unstimulated cells. Together, our data suggest that microglial stimulation by these TLRs may increase the resistance of the brain against pneumococcal infections.
Genetic Characterization of the Nucleotide Excision Repair System of
Neisseria gonorrhoeae
Authors: LeCuyer Brian E. , Criss Alison K. , Seifert H. Steven
Published: November 2009

Nucleotide excision repair (NER) is universally used to recognize and remove many types of DNA damage. In eubacteria, the NER system typically consists of UvrA, UvrB, UvrC, the UvrD helicase, DNA polymerase I, and ligase. In addition, when DNA damage blocks transcription, transcription-repair coupling factor (TRCF), the product of the
mfd
gene, recruits the Uvr complex to repair the damage. Previous work using selected mutants and assays have indicated that pathogenic
Neisseria
spp. carry a functional NER system. In order to comprehensively examine the role of NER in
Neisseria
gonorrhoeae
DNA recombination and repair processes, the predicted NER genes (
uvrA
,
uvrB
,
uvrC
,
uvrD
, and
mfd
) were each disrupted by a transposon insertion, and the
uvrB
and
uvrD
mutants were complemented with a copy of each gene in an ectopic locus. Each
uvr
mutant strain was highly sensitive to UV irradiation and also showed sensitivity to hydrogen peroxide killing, confirming that all of the NER genes in
N. gonorrhoeae
are functional. The effect of RecA expression on UV survival was minor in
uvr
mutants but much larger in the
mfd
mutant. All of the NER mutants demonstrated wild-type levels of pilin antigenic variation and DNA transformation. However, the
uvrD
mutant exhibited higher frequencies of PilC-mediated pilus phase variation and spontaneous mutation, a finding consistent with a role for UvrD in mismatch repair. We conclude that NER functions are conserved in
N. gonorrhoeae
and are important for the DNA repair capabilities of this strict human pathogen.
Genome-Wide Transposon Mutagenesis Identifies a Role for Host Neuroendocrine Stress Hormones in Regulating the Expression of Virulence Genes inSalmonella
Authors: Spencer H. , Karavolos M. H. , Bulmer D. M. , Aldridge P. , Chhabra S. R. , Winzer K. , Williams P. , Khan C. M. A.
Published: November 2009

Bacterial sensing of environmental signals plays a key role in regulating virulence and mediating bacterium-host interactions. The sensing of the neuroendocrine stress hormones epinephrine (adrenaline) and norepinephrine (noradrenaline) plays an important role in modulating bacterial virulence. We used MudJ transposon mutagenesis to globally screen for genes regulated by neuroendocrine stress hormones inSalmonella entericaserovar Typhimurium. We identified eight hormone-regulated genes, includingyhaK,iroC,nrdF,accC,yedP, STM3081, and the virulence-related genesvirKandmig14. The mammalian α-adrenergic receptor antagonist phentolamine reversed the hormone-mediated effects onyhaK,virK, andmig14but did not affect the other genes. The β-adrenergic receptor antagonist propranolol had no activity in these assays. ThevirKandmig14genes are involved in antimicrobial peptide resistance, and phenotypic screens revealed that exposure to neuroendocrine hormones increased the sensitivity ofS. Typhimurium to the antimicrobial peptide LL-37. AvirKmutant and avirKmig14double mutant also displayed increased sensitivity to LL-37. In contrast to enterohemorrhagicEscherichia coli(EHEC), we have found no role for the two-component systems QseBC and QseEF in the adrenergic regulation of any of the identified genes. Furthermore, hormone-regulated gene expression could not be blocked by the QseC inhibitor LED209, suggesting that sensing of hormones is mediated through alternative signaling pathways inS. Typhimurium. This study has identified a role for host-derived neuroendocrine stress hormones in downregulatingS. Typhimurium virulence gene expression to the benefit of the host, thus providing further insights into the field of host-pathogen communication.
The dihydropyridine analogue cerebrocrast blocks both T-type and L-type calcium currents
Authors: Drígeľová Mária , Tarabová Bohumila , Duburs Gunars , Lacinová Ľubica
Published: November 2009

Cerebrocrast is a novel lipophilic dihydropyridine derivative with potential neuroprotective and antidiabetic properties. We have analyzed its interaction with L-type (CaV1.2b) and T-type (CaV3.1) calcium channels using a whole-cell patch clamp in HEK 293 cells. Cerebrocrast inhibited current flux through both CaV1.2band CaV3.1 channels. In both cases, the drug was about 10-fold less effective than neutral dihydropyridines, but more efficient than the charged dihydropyridine amlodipine. IC50values for the CaV1.2bchannel were 586 ± 96 nmol/L and 178 ± 78 nmol/L at holding potentials of –80 mV and –50 mV, respectively. Approximately 50 µmol/L of cerebrocrast was needed to block 50% of the current amplitude in the CaV3.1 channel, but this inhibition was not facilitated by shifting the holding potential from –100 mV to –70 mV. Cerebrocrast did not alter current kinetics in either investigated channel, and the inhibition of calcium current was partly reversible or irreversible. In conclusion, the interaction of cerebrocrast with CaV3.1 lacked the typical characteristics of a state-dependent interaction, and voltage-dependent inhibition of CaV1.2bwas consistent with partial interaction with the inactivated state of the channel.
Multidrug resistance phosphoglycoprotein (ABCB1) expression in the guinea pig placenta: developmental changes and regulation by betamethasone
Authors: Kalabis Grazyna M. , Petropoulos Sophie , Gibb William , Matthews Stephen G.
Published: November 2009

Placental ABCB1 plays an important role in fetal protection against xenobiotics in the maternal circulation. Limited evidence indicates that glucocorticoids regulate ABCB1 expression in other tissues. Since approximately 10% of pregnant women are treated with synthetic glucocorticoids for threatened preterm labour, the effects of synthetic glucocorticoids on placental ABCB1 are important. We hypothesized that placental levels of ABCB1 are reduced in late gestation in the guinea pig and that synthetic glucocorticoids downregulate ABCB1 production. There was a significant decrease in placental Abcb1 mRNA expression in late gestation. Treatment of guinea pigs with betamethasone (1 mg/kg) on gestational days 40/41 and 50/51 resulted in a significant decrease in placental Abcb1 mRNA and protein expression. No sex differences were observed. Understanding the regulation of ABCB1 function will facilitate the development of treatment strategies for human fetal protection against maternally derived endobiotics and xenobiotics.
FIVEBRANE STRUCTURES
Authors: SATI HISHAM , SCHREIBER URS , STASHEFF JIM
Published: November 2009

We study the cohomological physics of fivebranes in type II and heterotic string theory. We give an interpretation of the one-loop term in type IIA, which involves the first and second Pontrjagin classes of spacetime, in terms of obstructions to having bundles with certain structure groups. Using a generalization of the Green–Schwarz anomaly cancellation in heterotic string theory which demands the target space to have a String structure, we observe that the "magnetic dual" version of the anomaly cancellation condition can be read as a higher analog of String structure, which we call Fivebrane structure. This involves lifts of orthogonal and unitary structures through higher connected covers which are not just 3- but even 7-connected. We discuss the topological obstructions to the existence of Fivebrane structures. The dual version of the anomaly cancellation points to a relation of string and Fivebrane structures under electric-magnetic duality.
AB INITIO CALCULATION OF THE LATTICE DYNAMICS OF THE ZnSe1-xTex ALLOY
Authors: BOUAMAMA K. , DJEMIA P. , LEBGA N. , KASSALI K.
Published: November 2009

The lattice dynamics of the ternary ZnSe 1-x Te x alloy have been studied using first-principles calculations. These are done using the density-functional perturbation theory (DFPT) within the local density approximation (LDA) and employing the virtual-crystal approximation (VCA). We study the variation of the optical phonon frequencies (ω TO and ω LO ), the high-frequency dielectric coefficient (ε∞) and the dynamic effective charge (Z*) as a function of the composition (x). We found that the ω TO and ω LO follow a quadratic law in x and agree well with the experiment which proves that the VCA is a reliable method for mixed modes determination (2 bonds-1 mode). The obtained ε∞ and Z* have a quadratic form with x. We have also predicted the behavior of the optical and acoustical phonons with x at the high symmetry point X and L.
CRYSTALLIZATION OF ANODIC ALUMINUM OXIDE MEMBRANES
Authors: YUE SONG , DU JUAN , ZHANG YUAN , CHEN DAPENG
Published: November 2009

Nanoporous anodic aluminum oxide membranes (AAM) were fabricated in oxalic acid electrolytes using a two-step anodization process. Membranes' structure and morphology were examined using scanning electron microscopy and X-ray diffraction after the annealing treatment. It was found that the crystallization temperature of the AAM are greatly dependent on their thickness. Aluminum is maintained under the protection of AAM even at 1100°C when the AAM's melting manifests.
A MODEL FOR THE TOTAL PRODUCTIVE MANUFACTURING ASSESSMENT AND IMPLEMENTATION
Authors: SHETTY DEVDAS , ALI AHAD , CHAPDELAINE JOHN J.
Published: November 2009

This research presents a comprehensive investigation of the implementation of Total Productive Manufacturing (TPM) in major US industries and assesses the status of its implementation. The identification and categorization of the key characteristics of a TPM implementation are developed. An extensive survey was developed and conducted that allows companies to identify how they fit within the TPM philosophy and the way they highlight areas for improvement. Based on the survey, a new methodology to implement TPM was developed. This procedure builds upon traditional TPM procedures and equipment selection tools and further adds non-traditional tools. Value Stream Mapping was added to improve understanding of material flow in the manufacturing process. Failure Mode and Effects Criticality Analysis (FMECA) procedures introduced equipment reliability and probability of failure into the selection process. The comprehensive TPM methodology was demonstrated as a visual tool entitled, TPM Decision Matrix. The tool allows selection tradeoffs of various resources that are available in the industry. The methodology was tested in industry through a TPM implementation. The results showed that the equipment effectiveness in the company has improved by the new TPM results. The results also include several other major recommendations that have significant potential for enhancing factory effectiveness.
Security in dynamic web content management systems applications
Authors: Vaidyanathan Ganesh , Mautone Steven
Published: November 2009

Introduction

The processes behind corporate efforts to create, manage, publish, and archive Web information has also evolved using Web Content Management Systems (WCMS). WCMS allow teams to maintain Web content in a dynamic fashion through a user friendly interface and a modular application approach. This dynamic "on-the-fly" content creation provides Web site authors several advantages including access to information stored in databases, ability to personalize Web pages according to individual user preferences, and the opportunity to deliver a much more interactive user experience than static Web pages alone.
11
However, there are distinct disadvantages as well. Dynamically generating Web content can significantly impact Web server performance, reduce the scalability of the Web site and create security vulnerabilities or denial of service.
11
Organizations are adopting information technology without understanding such security concerns.
1
Moreover, as Mostefaoui
7
points out, even though many attempts have been made to understand the security architecture, a generic security framework is needed. Recent research amplifies the concerns and benefits of security in open source systems.
2
However, there is a need for organizations to understand how to evaluate these open source systems and this paper highlights how an evaluation technique in terms of security may be used in an organization to assess a short list of possible WMCS systems. This article focuses on security issues in WCMS and the objective is to understand the security issues as well as to provide a generic security framework.

The contributions of this paper are to:

1. Integrate the goals of security with eight dimensions of WCMS,

2. Specify how to secure the eight dimensions of WCMS,

3. Formulate a framework of security using this integrated view of security goals and security dimensions, and

4. Address the security of the Web architecture at WCMS software application level using the framework and evaluate security features in popular WCMS used in the industry.
CMAC
Authors: Liu Sha , Fan Kai-Wei , Sinha Prasun
Published: November 2009

Low duty cycle operation is critical to conserve energy in wireless sensor networks. Traditional wake-up scheduling approaches either require periodic synchronization messages or incur high packet delivery latency due to the lack of any synchronization. To simultaneously achieve the seemingly contradictory goals of energy efficiency and low latency, the design of a new low duty-cycle MAC layer protocol called Convergent MAC (CMAC) is presented. CMAC avoids synchronization overhead while supporting low latency. By using zero communication when there is no traffic, CMAC allows sensor nodes to operate at very low duty cycles. When carrying traffic, CMAC first uses anycast to wake up forwarding nodes, and then converges gradually from route-suboptimal anycast with unsynchronized duty cycling to route-optimal unicast with synchronized scheduling. To validate our design and provide a usable module for the research community, CMAC has been implemented in TinyOS and evaluated on the Kansei testbed consisting of 105 XSM nodes. The results show that CMAC at 1% duty cycle significantly outperforms BMAC at 1% in terms of latency, throughput and energy efficiency. The performance of CMAC is also compared with other protocols using simulations, in which the results show for 1% and lower duty cycles, CMAC exhibits similar throughput and latency as CSMA/CA using much less energy, and outperforms SMAC, DMAC and GeRaF in almost all aspects.
Optimal base station placement in wireless sensor networks
Authors: Shi Yi , Hou Y. Thomas
Published: November 2009

Base station location has a significant impact on network lifetime performance for a sensor network. For a multihop sensor network, this problem is particularly challenging due to its coupling with data routing. This article presents an approximation algorithm that can guarantee (1 − ε)-optimal network lifetime performance for base station placement problem with any desired error bound ε > 0. The proposed (1 − ε)-optimal approximation algorithm is based on several novel techniques that makes it possible to reduce an infinite search space to a finite-element search space for base station location. The first technique used in this reduction is to discretize cost parameter (associated with energy consumption) with performance guarantee. Subsequently, the continuous search space can be broken up into a finite number of subareas. The second technique is to exploit the cost property of each subarea and represent it by a novel notion called fictitious cost point, each with guaranteed cost bounds. We give a proof that the proposed base station placement algorithm is (1− ε)-optimal. This approximation algorithm is simpler and faster than a state-of-the-art algorithm and represents the best known result to the base station placement problem.
A specification paradigm for the design and implementation of tangible user interfaces
Authors: Shaer Orit , Jacob Robert J.K.
Published: November 2009

Tangible interaction shows promise to significantly enhance computer-mediated support for activities such as learning, problem solving, and design. However, tangible user interfaces are currently considered challenging to design and build. Designers and developers of these interfaces encounter several conceptual, methodological, and technical difficulties. Among others, these challenges include: the lack of appropriate interaction abstractions, the shortcomings of current user interface software tools to address continuous and parallel interactions, as well as the excessive effort required to integrate novel input and output technologies. To address these challenges, we propose a specification paradigm for designing and implementing Tangible User Interfaces (TUIs), that enables TUI developers to specify the structure and behavior of a tangible user interface using high-level constructs which abstract away implementation details. An important benefit of this approach, which is based on User Interface Description Language (UIDL) research, is that these specifications could be automatically or semi-automatically converted into concrete TUI implementations. In addition, such specifications could serve as a common ground for investigating both design and implementation concerns by TUI developers from different disciplines.

Thus, the primary contribution of this article is a high-level UIDL that provides developers from different disciplines means for effectively specifying, discussing, and programming a broad range of tangible user interfaces. There are three distinct elements to this contribution: a visual specification technique that is based on Statecharts and Petri nets, an XML-compliant language that extends this visual specification technique, as well as a proof-of-concept prototype of a Tangible User Interface Management System (TUIMS) that semi-automatically translates high-level specifications into a program controlling specific target technologies.
Automated anomaly detection and performance modeling of enterprise applications
Authors: Cherkasova Ludmila , Ozonat Kivanc , Mi Ningfang , Symons Julie , Smirni Evgenia
Published: November 2009

Automated tools for understanding application behavior and its changes during the application lifecycle are essential for many performance analysis and debugging tasks. Application performance issues have an immediate impact on customer experience and satisfaction. A sudden slowdown of enterprise-wide application can effect a large population of customers, lead to delayed projects, and ultimately can result in company financial loss. Significantly shortened time between new software releases further exacerbates the problem of thoroughly evaluating the performance of an updated application. Our thesis is that online performance modeling should be a part of routine application monitoring. Early, informative warnings on significant changes in application performance should help service providers to timely identify and prevent performance problems and their negative impact on the service. We propose a novel framework for automated anomaly detection and application change analysis. It is based on integration of two complementary techniques: (i) a regression-based transaction model that reflects a resource consumption model of the application, and (ii) an application performance signature that provides a compact model of runtime behavior of the application. The proposed integrated framework provides a simple and powerful solution for anomaly detection and analysis of essential performance changes in application behavior. An additional benefit of the proposed approach is its simplicity: It is not intrusive and is based on monitoring data that is typically available in enterprise production environments. The introduced solution further enables the automation of capacity planning and resource provisioning tasks of multitier applications in rapidly evolving IT environments.
Insights into the Role of GILT in HLA Class II Antigen Processing and Presentation by Melanoma
Authors: Norton Duncan L. , Haque Azizul
Published: November 2009

Metastatic melanoma is one of the deadliest of skin cancers and is increasing in incidence. Since current treatment regimens are ineffective at controlling and/or curing the disease, novel approaches, such as immunotherapy, for treating this malignant disease are being explored. In this review, we discuss potential melanoma antigens (Ags) and their role in utilizing the HLA class II pathway to elicit tumor Ag-specificCD4+T cell responses in order to effectively induce long-lastingCD8+antitumor memory. We also discuss the role of endolysosomal cathepsins and Gamma-Interferon-inducible Lysosomal Thiol reductase (GILT) in Ag processing and presentation, and at enhancingCD4+T cell recognition of melanoma cells. This review also summarizes our current knowledge on GILT and highlights a novel mechanism of GILT-mediated immune responses against melanoma cells. At the end, we propose a strategy employing GILT in the development of a potential whole cell vaccine for combating metastatic melanoma.
Analytical Techniques for a Numerical Solution of the Linear Volterra Integral Equation of the Second Kind
Authors: Berenguer M. I. , Gámez D. , Garralda-Guillem A. I. , Ruiz Galán M. , Serrano Pérez M. C.
Published: November 2009

In this work we use analytical tools—Schauder bases and Geometric Series theorem—in order to develop a new method for the numerical resolution of the linear Volterra integral equation of the second kind.
Improved Performances of a Fluidized Bed Photoreactor by a Microscale Illumination System
Authors: Ciambelli Paolo , Sannino Diana , Palma Vincenzo , Vaiano Vincenzo , Mazzei Roberto S.
Published: November 2009

The performances of a gas‐solid two‐dimensional fluidized bed reactor in photocatalytic selective oxidation reactions, irradiated with traditional UV lamps or with a microscale illumination system based on UV emitting diodes (UVA‐LEDs), have been compared. In the photocatalytic oxidative dehydrogenation of cyclohexane to benzene on MoOx/TiO2‐A12O3
catalyst the use of UVA‐LEDs modules allowed to achieve a cyclohexane conversion and benzene yield higher than those obtained with traditional UV lamps. The better performances with UVA‐LEDs are due to the UVA‐LEDs small dimensions and small‐angle emittance, which allow photons beam be directed towards the photoreactor windows, reducing the dispersion outside of photoreactor or the optical path length. As a consequence, the effectively illuminated mass of catalyst is greater. We have found that this illumination system is efficient for photo‐oxidative dehydrogenation of cyclohexane to cyclohexene on sulphated MoOx/γ‐A12O3
and ethanol to acetaldehyde on VOx/TiO2.
A Temporal Model of Speech Production
Authors: Bell-Berti Fredericka , Harris Katherine S.
Published: November 2009

Existing models of speech production and coarticulation have failed to account for observations of real speech because they have considered timing to be a by-product of articulatory events instead of an integral organizing parameter of the speech motor plan. The model offered here considers time and timing relationships to be intrinsic to speech motor organization and the units of speech to be inherently dynamic gestures rather than static vocal tract configurations or invariant commands to the articulators.
Interarticulator Programming in Obstruent Production
Authors: Löfqvist Anders , Yoshioka Hirohide
Published: November 2009

Most work on speech motor control has been devoted to the spatial and temporal coordination of articulatory movements for successive units, segments or syllables, in the speech chain. An intrasegmental temporal domain has generally been lacking in speech production models, but such a domain is necessary at least for certain classes of speech sounds, e.g., voiceless obstruents, clicks, ejectives. The present paper examines the nature of laryngeal-oral coordination in voiceless obstruent production in different languages using the combined techniques of electromyography, transillumination and fiberoptic filming of the larynx together with aerodynamic and palatographic records for information on supralaryngeal articulations. The results suggest that laryngeal articulatory movements are organized in one or more continuous opening and closing gestures that are precisely coordinated with supralaryngeal events according to the aerodynamic requirements of speech production.
Some Effects of Speaking Rate on Phonetic Perception
Authors: Miller Joanne L.
Published: November 2009

This paper reviews a series of studies on the effects of variation in speaking rate on phonetic perception, in particular, on the identification of /b/ and /w/ in syllable-initial position. The major finding of these studies was that in a variety of tasks listeners adjusted for speaking rate when using the duration of the initial formant transitions to distinguish between /b/ and /w/: At slower rates of speech, a longer transition was needed to hear /w/ rather than /b/, and conversely at faster rates of speech. This effect occurred when rate was specified by the duration and acoustic-phonetic structure of the syllable containing the target consonant and, to a more limited extent, when it was specified by the duration of a subsequent syllable. Moreover, the influence of syllable duration on the processing of transition duration was also evident in young, prearticulate infants, suggesting that at least the rudiments of a system that provides perceptual constancy across rate is part of the linguistic endowment of the infant.
Temporal Information Processing in Speech Perception
Authors: Ventsov Anatoli V.
Published: November 2009

For a set of formal rules for the phonetic interpretation of speech during its perception one should have data concerning a possible structure and parameters of a subjective mechanism for processing temporal information, from segmenting the speech signal to making phonetic decisions. At present such data cannot be found in the literature. An attempt has been made to find out more about some parts of the subjective mechanism of duration measurement and comparison by studying the perception of tempo changes in short sound sequences. Running or ‘momentary’ tempo is shown to be the feature of tempo change perception, and possible procedures for its detection have been tested. A computational technique for getting the quantitative parameters of the mechanism is briefly described.