bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency Versus Time Domain Fatigue Analysis of a Semisubmersible Wind Turbine Tower
Authors: Kvittem Marit I. , Moan Torgeir
Published: August 2014

The current paper deals with a study of a semisubmersible wind turbine (WT), where short-term tower base bending moments and tower fatigue damage were estimated by a frequency domain (FD) method. Both a rigid structure assumption and a generalized degree-of-freedom (DOF) model for including the first flexible mode of the turbine tower were investigated. First, response to wind and wave loads was considered separately, then superposition was used to find the response to combined wind and wave loading. The bending moments and fatigue damage obtained by these methods were compared to results from a fully coupled, nonlinear time domain (TD) analysis. In this study a three column, catenary moored semisubmersible with the NREL 5 MW turbine mounted on one of the columns was modeled. The model was inspired by the WindFloat concept. The TD simulation tool used was Simo-Riflex-AeroDyn from Marintek and CeSOS. The FD method gave a good representation of the tower base bending moment histories for wave-only analyses, for the moderate sea states considered in these analyses. With the assumption that the structure is completely rigid, bending moments were underestimated, but including excitation of the elastic tower and blades, improved the results. The wind-induced low-frequency bending moments were not captured very well, which presumably comes from a combination of nonlinear effects being lost in the linearization of the thrust force and that the aerodynamic damping model was derived for a fixed turbine. Nevertheless, standard deviations of the bending moments were still reasonable. The FD model captured the combined wind and wave analyses quite well when a generalized coordinates model for wind excitation of the first bending mode of the turbine was included. The FD fatigue damage predictions were underestimated by 0–60%, corresponding to discrepancies in standard deviations of stress in the order of 0–20%.
Experimental Investigation on Droplet Behavior in a Transonic Compressor Cascade
Authors: Neupert Niklas , Ober Birger , Joos Franz
Published: August 2014

In recent years, overspray fogging has become a powerful means for power augmentation of industrial gas turbines (GT). Most of the studies concerning this topic focus on the problem from a thermodynamic point of view. Only a few studies, however, were undertaken to investigate the droplet behavior in the flow channel of a compressor. In this paper, results of experimental investigation of a water laden flow through a transonic compressor cascade are presented. A finely dispersed spray was used in the measurements (D10 < 10 μm). Results of the droplet behavior are shown in terms of shadowgraphy images and images of the blade surface film pattern. The angle of attack, the incoming velocity, and the water load were varied. The qualitative observations are related to laser Doppler and phase Doppler anemometer (LDA/PDA) data taken in the flow channel and at the outlet of the cascade. The data represent a base for numerical and mean line models of two-phase compressor flow.
Effect of segmentation algorithms on the performance of computerized detection of lung nodules in CT
Authors: Guo Wei , Li Qiang
Published: August 2014

Purpose:

The purpose of this study is to reveal how the performance of lung nodule segmentation algorithm impacts the performance of lung nodule detection, and to provide guidelines for choosing an appropriate segmentation algorithm with appropriate parameters in a computer‐aided detection (CAD) scheme.

Methods:

The database consisted of 85 CT scans with 111 nodules of 3 mm or larger in diameter from the standard CT lung nodule database created by the Lung Image Database Consortium. The initial nodule candidates were identified as those with strong response to a selective nodule enhancement filter. A uniform viewpoint reformation technique was applied to a three‐dimensional nodule candidate to generate 24 two‐dimensional (2D) reformatted images, which would be used to effectively distinguish between true nodules and false positives. Six different algorithms were employed to segment the initial nodule candidates in the 2D reformatted images. Finally, 2D features from the segmented areas in the 24 reformatted images were determined, selected, and classified for removal of false positives. Therefore, there were six similar CAD schemes, in which only the segmentation algorithms were different. The six segmentation algorithms included the fixed thresholding (FT), Otsu thresholding (OTSU), fuzzy C‐means (FCM), Gaussian mixture model (GMM), Chan and Vese model (CV), and local binary fitting (LBF). The mean Jaccard index and the mean absolute distance (Dmean) were employed to evaluate the performance of segmentation algorithms, and the number of false positives at a fixed sensitivity was employed to evaluate the performance of the CAD schemes.

Results:

For the segmentation algorithms of FT, OTSU, FCM, GMM, CV, and LBF, the highest mean Jaccard index between the segmented nodule and the ground truth were 0.601, 0.586, 0.588, 0.563, 0.543, and 0.553, respectively, and the corresponding Dmean were 1.74, 1.80, 2.32, 2.80, 3.48, and 3.18 pixels, respectively. With these segmentation results of the six segmentation algorithms, the six CAD schemes reported 4.4, 8.8, 3.4, 9.2, 13.6, and 10.4 false positives per CT scan at a sensitivity of 80%.

Conclusions:

When multiple algorithms are available for segmenting nodule candidates in a CAD scheme, the “optimal” segmentation algorithm did not necessarily lead to the “optimal” CAD detection performance.
The ErbB4 CYT2 variant protects EGFR from ligand-induced degradation to enhance cancer cell motility
Authors: Kiuchi Tai , Ortiz-Zapater Elena , Monypenny James , Matthews Daniel R. , Nguyen Lan K. , Barbeau Jody , Coban Oana , Lawler Katherine , Burford Brian , Rolfe Daniel J. , de Rinaldis Emanuele , Dafou Dimitra , Simpson Michael A. , Woodman Natalie , Pinder Sarah , Gillett Cheryl E. , Devauges Viviane , Poland Simon P. , Fruhwirth Gilbert , Marra Pierfrancesco , Boersma Ykelien L. , Plückthun Andreas , Gullick William J. , Yarden Yosef , Santis George , Winn Martyn , Kholodenko Boris N. , Martin-Fernandez Marisa L. , Parker Peter , Tutt Andrew , Ameer-Beg Simon M. , Ng Tony
Published: August 2014

Dimerization of EGFR with an ErbB4 receptor variant increases growth factor–induced migration of breast cancer cells.
Factor in Oocyte Assists Reprogramming
Authors: Purnell Beverly A.
Published: August 2014

Human oocyte reprogramming of the somatic nucleus involves histone chaperone ASF1A.
No Blood Cells Without Cyclin D
Authors: Gough Nancy R.
Published: August 2014

Conditional knockout in adult mice of D-type cyclins results in complete loss of hematopoietic cells.
How Ebola Shuts Down Antiviral Signaling
Authors: VanHook Annalisa M.
Published: August 2014

An Ebola virus protein selectively inhibits nuclear import of STAT1 to block interferon-induced antiviral responses.
Synthesis of Metallo-β-Lactamase VIM-2 Is Associated with a Fitness Reduction in Salmonella enterica Serovar Typhimurium
Authors: Cordeiro Nicolás F. , Chabalgoity José A. , Yim Lucía , Vignoli Rafael
Published: August 2014

Antibiotic resistance, especially due to β-lactamases, has become one of the main obstacles in the correct treatment of
Salmonella
infections; furthermore, antibiotic resistance determines a gain of function that may encompass a biological cost, or fitness reduction, to the resistant bacteria. The aim of this work was to determine
in vitro
if the production of the class B β-lactamase VIM-2 determined a fitness cost for
Salmonella enterica
serovar Typhimurium. To that end the gene
bla
VIM-2
was cloned into the virulent strain
S
. Typhimurium SL1344, using both the tightly regulated pBAD22 vector and the natural plasmid pST12, for inducible and constitutive expression, respectively. Fitness studies were performed by means of motility, growth rate, invasiveness in epithelial cells, and plasmid stability. The expression of
bla
VIM-2
was accompanied by alterations in micro- and macroscopic morphology and reduced growth rate and motility, as well as diminished invasiveness in epithelial cells. These results suggest that VIM-2 production entails a substantial fitness cost for
S
. Typhimurium, which in turn may account for the extremely low number of reports of metallo-β-lactamase-producing
Salmonella
spp.
Triclosan Can Select for an AdeIJK-Overexpressing Mutant of Acinetobacter baumannii ATCC 17978 That Displays Reduced Susceptibility to Multiple Antibiotics
Authors: Fernando Dinesh M. , Xu Wayne , Loewen Peter C. , Zhanel George G. , Kumar Ayush
Published: August 2014

In order to determine if triclosan can select for mutants of
Acinetobacter baumannii
ATCC 17978 that display reduced susceptibilities to antibiotics, we isolated a triclosan-resistant mutant,
A. baumannii
AB042, by serial passaging of
A. baumannii
ATCC 17978 in growth medium supplemented with triclosan. The antimicrobial susceptibility of AB042 was analyzed by the 2-fold serial dilution method. Expression of five different resistance-nodulation-division (RND) pump-encoding genes (
adeB
,
adeG
,
adeJ
,
A1S
_
2818
, and
A1S
_
3217
), two outer membrane porin-encoding genes (
carO
and
oprD
), and the MATE family pump-encoding gene
abeM
was analyzed using quantitative reverse transcriptase (qRT) PCR.
A. baumannii
AB042 exhibited elevated resistance to multiple antibiotics, including piperacillin-tazobactam, doxycycline, moxifloxacin, ceftriaxone, cefepime, meropenem, doripenem, ertapenem, ciprofloxacin, aztreonam, tigecycline, and trimethoprim-sulfamethoxazole, in addition to triclosan. Genome sequencing of
A. baumannii
AB042 revealed a
116
G→V mutation in
fabI
, the gene encoding the target enzyme for triclosan. Expression analysis of efflux pumps showed overexpression of the AdeIJK pump, and sequencing of
adeN
, the gene that encodes the repressor of the
adeIJK
operon, revealed a 73-bp deletion which would cause a premature termination of translation, resulting in an inactive truncated AdeN protein. This work shows that triclosan can select for mutants of
A. baumannii
that display reduced susceptibilities to multiple antibiotics from chemically distinct classes in addition to triclosan resistance. This multidrug resistance can be explained by the overexpression of the AdeIJK efflux pump.
Genetic and Kinetic Characterization of the Novel AmpC β-Lactamases DHA-6 and DHA-7
Authors: Pérez-Llarena Francisco José , Zamorano Laura , Kerff Frédéric , Beceiro Alejandro , García Patricia , Miró Elisenda , Larrosa Nieves , Gómez-Bertomeu Frederic , Méndez José Antonio , González-López Juan José , Oliver Antonio , Galleni Moreno , Navarro Ferran , Bou Germán
Published: August 2014

During a Spanish surveillance study, two natural variants of DHA β-lactamases, DHA-6 and DHA-7, were found, with the replacements Ala226Thr and Phe322Ser, respectively, with respect to DHA-1. The DHA-6 and DHA-7 enzymes were isolated from
Escherichia coli
and
Enterobacter cloacae
clinical isolates, respectively. The aim of this study was to genetically, microbiologically, and biochemically characterize the DHA-6 and DHA-7 β-lactamases. The
bla
DHA-6
and
bla
DHA-7
genes were located in the I1 and HI2 incompatibility group plasmids of 87.3 and 310.4 kb, respectively. The genetic contexts of
bla
DHA-6
and
bla
DHA-7
were similar to that already described for the
bla
DHA-1
gene and included the
qnrB4
and
aadA
genes. The MICs for cephalothin, aztreonam, cefotaxime, and ceftazidime were 8- to 32-fold lower for DHA-6 than for DHA-1 or DHA-7 expressed in the same isogenic
E. coli
TG1 strain. Interestingly, the MIC for cefoxitin was higher in the DHA-6-expressing transformant than in DHA-1 or DHA-7. Biochemical studies with pure β-lactamases revealed slightly lower catalytic efficiencies of DHA-6 against cephalothin, ceftazidime, and cefotaxime than those of DHA-1 and DHA-7. To understand this behavior, stability experiments were carried out and showed that the DHA-6 protein displayed significantly higher stability than the DHA-1 and DHA-7 enzymes. The proximity of Thr226 to the N terminus in the tertiary protein structure in DHA-6 may promote this stabilization and, consequently, may induce a slight reduction in the dynamic of this enzyme that primarily affects the hydrolysis of some of the bulkiest antibiotics.
Characterization of a P1-Like Bacteriophage Carrying an SHV-2 Extended-Spectrum β-Lactamase from an Escherichia coli Strain
Authors: Billard-Pomares Typhaine , Fouteau Stéphanie , Jacquet Marie Elise , Roche David , Barbe Valérie , Castellanos Miguel , Bouet Jean Yves , Cruveiller Stéphane , Médigue Claudine , Blanco Jorge , Clermont Olivier , Denamur Erick , Branger Catherine
Published: August 2014

P1 bacteriophages lysogenize bacteria as independent plasmid-like elements. We describe here a P1-like bacteriophage, RCS47, carrying a
bla
SHV-2
gene, isolated from a clinical strain of
Escherichia coli
from phylogroup B1, and we report the prevalence of P1-like prophages in natural
E. coli
isolates. We found that 70% of the sequence of RCS47, a 115-kb circular molecule, was common to the reference P1 bacteriophage under GenBank accession no.
AF234172.1
, with the shared sequences being 99% identical. RCS47 had acquired two main foreign DNA fragments: a 9,636-bp fragment mobilized by two IS
26
elements containing a
bla
SHV-2
gene, and an 8,544-bp fragment mobilized by two IS
5
elements containing an operon encoding a dimethyl sulfoxide reductase. The reference P1 prophage plasmid replication gene belonged to the IncY incompatibility group, whereas that of RCS47 was from an unknown group. The lytic capacity of RCS47 and
bla
SHV-2
gene transduction, through the lysogenization of RCS47 in the recipient
E. coli
strains, were not demonstrated. The prevalence of P1-like prophages in various animal and human
E. coli
strain collections, as determined by the PCR detection of
repL
, the lytic replication gene, was 12.6%. No differences in the prevalences of these prophages were found between extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing strains (
P
= 0.69), but this prevalence was lower in phylogroup B2 than in the other phylogroups (
P
= 0.008), suggesting epistatic interactions between P1 family phages and the genetic background of
E. coli
strains. P1-like phages are part of the mobile elements that carry antibiotic resistance. The high prevalence of P1-like prophages suggests their role may be underestimated.
Novel Insights into the Mechanism of Inhibition of MmpL3, a Target of Multiple Pharmacophores in Mycobacterium tuberculosis
Authors: Li Wei , Upadhyay Ashutosh , Fontes Fabio L. , North E. Jeffrey , Wang Yuehong , Crans Debbie C. , Grzegorzewicz Anna E. , Jones Victoria , Franzblau Scott G. , Lee Richard E. , Crick Dean C. , Jackson Mary
Published: August 2014

MmpL3, a resistance-nodulation-division (RND) superfamily transporter, has been implicated in the formation of the outer membrane of
Mycobacterium tuberculosis
; specifically, MmpL3 is required for the export of mycolic acids in the form of trehalose monomycolates (TMM) to the periplasmic space or outer membrane of
M. tuberculosis
. Recently, seven series of inhibitors identified by whole-cell screening against
M. tuberculosis
, including the antituberculosis drug candidate SQ109, were shown to abolish MmpL3-mediated TMM export. However, this mode of action was brought into question by the broad-spectrum activities of some of these inhibitors against a variety of bacterial and fungal pathogens that do not synthesize mycolic acids. This observation, coupled with the ability of three of these classes of inhibitors to kill nonreplicating
M. tuberculosis
bacilli, led us to investigate alternative mechanisms of action. Our results indicate that the inhibitory effects of adamantyl ureas, indolecarboxamides, tetrahydropyrazolopyrimidines, and the 1,5-diarylpyrrole BM212 on the transport activity of MmpL3 in actively replicating
M. tuberculosis
bacilli are, like that of SQ109, most likely due to their ability to dissipate the transmembrane electrochemical proton gradient. In addition to providing novel insights into the modes of action of compounds reported to inhibit MmpL3, our results provide the first explanation for the large number of pharmacophores that apparently target this essential inner membrane transporter.
Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis
Authors: Yin Jianhua , Mao Yinting , Ju Lili , Jin Miao , Sun Yiyang , Jin Shouguang , Gao Haichun
Published: August 2014

β-Lactam antibiotics were the earliest discovered and are the most widely used group of antibiotics that work by inactivating penicillin-binding proteins to inhibit peptidoglycan biosynthesis. As one of the most efficient defense strategies, many bacteria produce β-lactam-degrading enzymes, β-lactamases, whose biochemical functions and regulation have been extensively studied. A signal transduction pathway for β-lactamase induction by β-lactam antibiotics, consisting of the major peptidoglycan recycling enzymes and the LysR-type transcriptional regulator, AmpR, has been recently unveiled in some bacteria. Because inactivation of some of these proteins, especially the permease AmpG and the β-hexosaminidase NagZ, results in substantially elevated susceptibility to the antibiotics, these have been recognized as potential therapeutic targets. Here, we show a contrasting scenario in
Shewanella oneidensis
, in which the homologue of AmpR is absent. Loss of AmpG or NagZ enhances β-lactam resistance drastically, whereas other identified major peptidoglycan recycling enzymes are dispensable. Moreover, our data indicate that there exists a parallel signal transduction pathway for β-lactamase induction, which is independent of either AmpG or NagZ.
In Vivo
Efficacy of Apramycin in Murine Infection Models
Authors: Meyer Martin , Freihofer Pietro , Scherman Michael , Teague Joanne , Lenaerts Anne , Böttger Erik C.
Published: August 2014

Apramycin is a unique aminoglycoside with a dissociation of antibacterial activity and ototoxicity. We assessed the antibacterial efficacy of apramycin in two murine models of infection,
Mycobacterium tuberculosis
aerosol infection and
Staphylococcus aureus
septicemia. In both infection models, the efficacy of apramycin was comparable to that of amikacin. These results suggest that apramycin has the potential to become a clinically useful agent against drug-resistant pathogens and support further development of this promising unique aminoglycoside.
Identification and Characterization of Linezolid-Resistantcfr-Positive Staphylococcus aureus USA300 Isolates from a New York City Medical Center
Authors: Locke Jeffrey B. , Zuill Douglas E. , Scharn Caitlyn R. , Deane Jennifer , Sahm Daniel F. , Goering Richard V. , Jenkins Stephen G. , Shaw Karen J.
Published: August 2014

Thecfrgene was identified in three linezolid-resistant USA300 methicillin-resistantStaphylococcus aureus(MRSA) isolates collected over a 3-day period at a New York City medical center in 2011 as part of a routine surveillance program. Each isolate possessed a plasmid containing a pSCFS3-likecfrgene environment. Transformation of thecfr-bearing plasmids into theS. aureusATCC 29213 background recapitulated the expected Cfr antibiogram, including resistance to linezolid, tiamulin, clindamycin, and florfenicol and susceptibility to tedizolid.
Ceftaroline-Fosamil Efficacy against Methicillin-Resistant Staphylococcus aureus in a Rabbit Prosthetic Joint Infection Model
Authors: Gatin Laure , Saleh-Mghir Azzam , Tasse Jason , Ghout Idir , Laurent Frédéric , Crémieux Anne-Claude
Published: August 2014

Ceftaroline (CPT), the active metabolite of the prodrug ceftaroline-fosamil (CPT-F), demonstrates
in vitro
bactericidal activity against methicillin-resistant
Staphylococcus aureus
(MRSA) and is effective in rabbit models of difficult-to-treat MRSA endocarditis and acute osteomyelitis. However, its
in vivo
efficacy in a prosthetic joint infection (PJI) model is unknown. Using a MRSA-infected knee PJI model in rabbits, the efficacies of CPT-F or vancomycin (VAN) alone and combined with rifampin (RIF) were compared. After each partial knee replacement with a silicone implant that fit into the tibial intramedullary canal was performed, 5 × 10
7
MRSA CFU (MICs of 0.38, 0.006, and 1 mg/liter for CPT, RIF, and VAN, respectively) was injected into the knee. Infected animals were randomly assigned to receive no treatment (controls) or CPT-F (60 mg/kg of body weight intramuscularly [i.m.]), VAN (60 mg/kg i.m.), CPT-F plus RIF (10 mg/kg i.m.), or VAN plus RIF starting 7 days postinoculation and lasting for 7 days. Surviving bacteria in crushed tibias were counted 3 days after ending treatment. Although the
in vivo
mean log
10
CFU/g of CPT-treated (3.0 ± 0.9,
n
= 12) and VAN-treated (3.5 ± 1.1,
n
= 12) crushed bones was significantly lower than those of controls (5.6 ± 1.1,
n
= 14) (
P
< 0.001), neither treatment fully sterilized the bones (3/12 were sterile with each treatment). The mean log
10
CFU/g values for the antibiotics in combination with RIF were 1.9 ± 0.5 (12/14 were sterile) for CPT-F and 1.9 ± 0.5 (12/14 were sterile) for VAN. In this MRSA PJI model, the efficacies of CPT-F and VAN did not differ; thus, CPT appears to be a promising antimicrobial agent for the treatment of MRSA PJIs.
Molecular Characterization of Streptococcus agalactiae Isolates Harboring Small
erm
(T)-Carrying Plasmids
Authors: Compain Fabrice , Hays Constantin , Touak Gérald , Dmytruk Nicolas , Trieu-Cuot Patrick , Joubrel Caroline , Poyart Claire
Published: August 2014

Among 1,827 group B
Streptococcus
(GBS) strains collected between 2006 and 2013 by the French National Reference Center for Streptococci, 490 (26.8%) strains were erythromycin resistant. The
erm
(T) resistance gene was found in six strains belonging to capsular polysaccharides Ia, III, and V and was carried by the same mobilizable plasmid, which could be efficiently transferred by mobilization to GBS and
Enterococcus faecalis
recipients, thus promoting a broad dissemination of
erm
(T).
Association and Virulence Gene Expression Vary among Serotype III Group B Streptococcus Isolates following Exposure to Decidual and Lung Epithelial Cells
Authors: Korir Michelle L. , Knupp David , LeMerise Kathryn , Boldenow Erica , Loch-Caruso Rita , Aronoff David M. , Manning Shannon D.
Published: August 2014

Group B
Streptococcus
(GBS) causes severe disease in neonates, the elderly, and immunocompromised individuals. GBS species are highly diverse and can be classified by serotype and multilocus sequence typing. Sequence type 17 (ST-17) strains cause invasive neonatal disease more frequently than strains of other STs. Attachment and invasion of host cells are key steps in GBS pathogenesis. We investigated whether four serotype III strains representing ST-17 (two strains), ST-19, and ST-23 differ in their abilities to attach to and invade both decidual cells and lung epithelial cells. Virulence gene expression following host cell association and exposure to amnion cells was also tested. The ST-17 strains differed in their abilities to attach to and invade decidual cells, whereas there were no differences with lung epithelial cells. The ST-19 and ST-23 strains, however, attached to and invaded decidual cells less than both ST-17 strains. Although the ST-23 strain attached to lung epithelial cells better than ST-17 and -19 strains, none of the strains effectively invaded the lung epithelial cells. Notably, the association with host cells resulted in the differential expression of several virulence genes relative to basal expression levels. Similar expression patterns of some genes were observed regardless of cell type used. Collectively, these results show that GBS strains differ in their abilities to attach to distinct host cell types and express key virulence genes that are relevant to the disease process. Enhancing our understanding of pathogenic mechanisms could aid in the identification of novel therapeutic targets or vaccine candidates that could potentially decrease morbidity and mortality associated with neonatal infections.
HilD Induces Expression of Salmonella Pathogenicity Island 2 Genes by Displacing the Global Negative Regulator H-NS from
ssrAB
Authors: Martínez Luary C. , Banda María M. , Fernández-Mora Marcos , Santana Francisco J. , Bustamante Víctor H.
Published: August 2014

Salmonella
pathogenicity islands 1 and 2 (SPI-1 and SPI-2) have essential roles in the pathogenesis of
Salmonella enterica
. Previously, we reported transcriptional cross talk between SPI-1 and SPI-2 when the SPI-1 regulator HilD induces expression of the SsrA/B two-component system, the central positive regulator of SPI-2, during the growth of
Salmonella
to late stationary phase in LB rich medium. Here, we further define the mechanism of the HilD-mediated expression of
ssrAB
. Expression analysis of
cat
transcriptional fusions containing different regions of
ssrAB
revealed the presence of negative regulatory sequences located downstream of the
ssrAB
promoter. In the absence of these negative
cis
elements,
ssrAB
was expressed in a HilD-independent manner and was no longer repressed by the global regulator H-NS. Consistently, when the activity of H-NS was inactivated, the expression of
ssrAB
also became independent of HilD. Furthermore, electrophoretic mobility shift assays showed that both HilD and H-NS bind to the
ssrAB
region containing the repressing sequences. Moreover, HilD was able to displace H-NS bound to this region, whereas H-NS did not displace HilD. Our results support a model indicating that HilD displaces H-NS from a region downstream of the promoter of
ssrAB
by binding to sites overlapping or close to those sites bound by H-NS, which leads to the expression of
ssrAB
. Although the role of HilD as an antagonist of H-NS has been reported before for other genes, this is the first study showing that HilD is able to effectively displace H-NS from the promoter of one of its target genes.
Discovery of Novel Peptides Regulating Competence Development in Streptococcus mutans
Authors: Ahn Sang-Joon , Kaspar Justin , Kim Jeong Nam , Seaton Kinda , Burne Robert A.
Published: August 2014

A MarR-like transcriptional repressor (RcrR) and two predicted ABC efflux pumps (RcrPQ) encoded by a single operon were recently shown to be dominant regulators of stress tolerance and development of genetic competence in the oral pathogen
Streptococcus mutans
. Here, we focused on polar (Δ
rcrR
-P) and nonpolar (Δ
rcrR
-NP)
rcrR
mutants, which are hyper- and nontransformable, respectively, to dissect the mechanisms by which these mutations impact competence. We discovered two open reading frames (ORFs) in the 3′ end of the
rcrQ
gene that encode peptides of 27 and 42 amino acids (aa) which are also dramatically upregulated in the Δ
rcrR
-NP strain. Deletion of, or start codon mutations in, the ORFs for the peptides in the Δ
rcrR
-NP background restored competence and sensitivity to competence-stimulating peptide (CSP) to levels seen in the Δ
rcrR
-P strain. Overexpression of the peptides adversely affected competence development. Importantly, overexpression of mutant derivatives of the ABC exporters that lacked the peptides also resulted in impaired competence. FLAG-tagged versions of the peptides could be detected in
S. mutans
, and FLAG tagging of the peptides impaired their function. The competence phenotypes associated with the various mutations, and with overexpression of the peptides and ABC transporters, were correlated with the levels of ComX protein in cells. Collectively, these studies revealed multiple novel mechanisms for regulation of competence development by the components of the
rcrRPQ
operon. Given their intimate role in competence and stress tolerance, the
rcrRPQ
-encoded peptides may prove to be useful targets for therapeutics to diminish the virulence of
S. mutans
.
External manifestations of Gardner’s syndrome as the presenting clinical entity
Authors: Agrawal Deepak , Newaskar Vilas , Shrivastava Sanket , Nayak Prathibha Anand
Published: August 2014

Gardner's syndrome is an autosomal dominant disease characterised by the presence of colonic polyposis, osteomas and a multitude of soft tissue tumours. Pathological features such as osteomas of the mandible, skull and facial skeleton are unaesthetic as well as incapacitating. We present the case of a 22-year-old man with pain and discharge from the left eye and a firm swelling in the left infraorbital region leading to proptosis of the left eye. A detailed examination of the patient led to the presence of a large osteoma in the left orbital region, multiple cystic lesion, corneal opacity and parapapillary atrophy in the left eye. Radiography revealed the presence of multiple unerupted supernumerary teeth and osteomas. Colonoscopic findings showed the presence of multiple polyps. Thus, external manifestations of the patient's facial region led to the establishment of the diagnosis of Gardner's syndrome. The importance of our case highlights the necessity of maintaining a high vigilance with regard to the occurrence of such an entity.
Eyelid reanimation, neurotisation, and transplantation of the cornea in a patient with facial palsy
Authors: Allevi Fabiana , Fogagnolo Paolo , Rossetti Luca , Biglioli Federico
Published: August 2014

Patients affected by facial palsy suffer from failure to fully close the eyelids; the resulting eye exposure can lead to dry eye syndrome, loss of epithelial integrity, corneal ulceration and infections. Corneal anaesthesia exacerbates risk of corneal damage in these patients. Eyelid paralysis-associated corneal lesions may induce severe visual impairment, for which the ideal treatment is corneal transplantation, a procedure contraindicated in patients with corneal sensitivity and inadequate eyelid closure. We present the case of a patient affected by unilateral facial palsy associated with corneal anaesthesia, due to seventh and fifth cranial nerve damage following homolateral eighth cranial nerve surgery. The patient underwent surgery to re-establish eyelid and corneal competence, and then received a corneal graft with consequent amelioration of visual acuity. This is the first case of associated corneal anaesthesia and facial palsy that was comprehensively treated with a set of surgical procedures, including a corneal transplant.
Bubble formation occurs in insulin pumps in response to changes in ambient temperature and atmospheric pressure but not as a result of vibration
Authors: Lopez Prudence E , King Bruce R , Goss Peter W , Chockalingam Ganesh
Published: August 2014

Introduction

Bubble formation in insulin pump giving sets is a common problem. We studied change in temperature, change in atmospheric pressure, and vibration as potential mechanisms of bubble formation.

Methods

5 Animas 2020 pumps with 2 mL cartridges and Inset II infusion systems, 5 Medtronic Paradigm pumps with 1.8 mL cartridge and Quickset and 3 Roche Accu-chek pumps with 3.15 mL cartridges were used. Temperature study: insulin pumps were exposed to a temperature change from 4°C to 37°C. Pressure study: insulin pumps were taken to an altitude of 300 m. Vibration study: insulin pumps were vigorously shaken. All were observed for bubble formation.

Results

Bubble formation was observed with changes in temperature and atmospheric pressure. Bubble formation did not occur with vibration.

Discussion

Changes in insulin temperature and atmospheric pressure are common and may result in bubble formation. Vibration may distribute bubbles but does not cause bubble formation.
Patients as teachers: a randomised controlled trial on the use of personal stories of harm to raise awareness of patient safety for doctors in training
Authors: Jha Vikram , Buckley Hannah , Gabe Rhian , Kanaan Mona , Lawton Rebecca , Melville Colin , Quinton Naomi , Symons Jools , Thompson Zoe , Watt Ian , Wright John
Published: August 2014

Background

Patient safety training often provides learners with a health professional's perspective rather than the patient's. Personal narratives of health-related harm allow patients to share their stories with health professionals to influence clinical behaviour by rousing emotions and improving attitudes to safety.

Aim

This study measured the impact of patient narratives used to train junior doctors in patient safety.

Methods

An open, multi-centre, two-arm, parallel design randomised controlled trial was conducted in the North Yorkshire East Coast Foundation School (NYECFS). The intervention consisted of 1-h-long patient narratives followed by discussion. The control arm received conventional faculty-delivered teaching. The Attitude to Patient Safety Questionnaire (APSQ) and the Positive and Negative Affect Schedule (PANAS) were used to measure the impact of the intervention.

Results

142 trainees received the intervention; 141 the control teaching. There was no evidence of a difference in post-intervention APSQ scores between the groups. There was a statistically significant difference in the underlying distribution of both post PA (positive affect) and post NA (negative affect) scores between the groups on the PANAS (p<0.001) with indications of both higher PA and NA scores in the intervention group.

Conclusions

Involving patients with experiences of safety incidents in training has an ideological appeal and seems an obvious choice in designing safety interventions. On the basis of our primary outcome measure, we were unable to demonstrate effectiveness of the intervention in changing general attitudes to safety compared to control. While the intervention may impact on emotional engagement and learning about communication, we remain uncertain whether this will translate into improved behaviours in the clinical context or indeed if there are any negative effects.

Trial registration number

Grant reference no. RP-PG-0108-10049.
Importance of carcinoma-associated fibroblast-derived proteins in clinical oncology
Authors: Valcz Gabor , Sipos Ferenc , Tulassay Zsolt , Molnar Bela , Yagi Yukako
Published: August 2014

Carcinoma-associated fibroblast (CAF) as prominent cell type of the tumour microenvironment has complex interaction with both the cancer cells and other non-neoplastic surrounding cells. The CAF-derived regulators and extracellular matrix proteins can support cancer progression by providing a protective microenvironment for the cancer cells via reduction of chemotherapy sensitivity. On the other hand, these proteins may act as powerful prognostic markers as well as potential targets of anticancer therapy. In this review, we summarise the clinical importance of the major CAF-derived signals influencing tumour behaviour and determining the outcome of chemotherapy.
Perceived neighbourhood social cohesion and myocardial infarction
Authors: Kim Eric S , Hawes Armani M , Smith Jacqui
Published: August 2014

Background

The main strategy for alleviating heart disease has been to target individuals and encourage them to change their health behaviours. Although important, emphasis on individuals has diverted focus and responsibility away from neighbourhood characteristics, which also strongly influence people's behaviours. Although a growing body of research has repeatedly demonstrated strong associations between neighbourhood characteristics and cardiovascular health, it has typically focused on negative neighbourhood characteristics. Only a few studies have examined the potential health enhancing effects of positive neighbourhood characteristics, such as perceived neighbourhood social cohesion.

Methods

Using multiple logistic regression models, we tested whether higher perceived neighbourhood social cohesion was associated with lower incidence of myocardial infarction. Prospective data from the Health and Retirement Study—a nationally representative panel study of American adults over the age of 50—were used to analyse 5276 participants with no history of heart disease. Respondents were tracked for 4 years and analyses adjusted for relevant sociodemographic, behavioural, biological and psychosocial factors.

Results

In a model that adjusted for age, gender, race, marital status, education and total wealth, each SD increase in perceived neighbourhood social cohesion was associated with a 22% reduced odds of myocardial infarction (OR=0.78, 95% CI 0.63 to 0.94. The association between perceived neighbourhood social cohesion and myocardial infarction remained even after adjusting for behavioural, biological and psychosocial covariates.

Conclusions

Higher perceived neighbourhood social cohesion may have a protective effect against myocardial infarction.
The pulse duration of electrical stimulation influences H-reflexes but not corticospinal excitability for tibialis anterior
Authors: Hindle Alyssa R. , Lou Jenny W.H. , Collins David F.
Published: August 2014

The afferent volley generated by neuromuscular electrical stimulation (NMES) influences corticospinal (CS) excitability and frequent NMES sessions can strengthen CS pathways, resulting in long-term improvements in function. This afferent volley can be altered by manipulating NMES parameters. Presently, we manipulated one such parameter, pulse duration, during NMES over the common peroneal nerve and assessed the influence on H-reflexes and CS excitability. We hypothesized that compared with shorter pulse durations, longer pulses would (i) shift the H-reflex recruitment curve to the left, relative to the M-wave curve; and (ii) increase CS excitability more. Using 3 pulse durations (50, 200, 1000 μs), M-wave and H-reflex recruitment curves were collected and, in separate experiments, CS excitability was assessed by comparing motor evoked potentials elicited before and after 30 min of NMES. Despite finding a leftward shift in the H-reflex recruitment curve when using the 1000 μs pulse duration, consistent with a larger afferent volley for a given efferent volley, the increases in CS excitability were not influenced by pulse duration. Hence, although manipulating pulse duration can alter the relative recruitment of afferents and efferents in the common peroneal nerve, under the present experimental conditions it is ineffective for maximizing CS excitability for rehabilitation.
Factors influencing Brown Pelican (Pelecanus occidentalis) foraging movement patterns during the breeding season
Authors: Walter S.T. , Leberg P.L. , Dindo J.J. , Karubian J.K.
Published: August 2014

During the breeding season, seabird foraging behaviors are driven by a combination of individual- and external-based factors. This study evaluated how two individual-based factors (body condition and sex) and two external factors (nest stage and colony size), and their interactions, were related to movement. To do so, we used movement data obtained from 22 GPS-tag-equipped Brown Pelicans (Pelecanus occidentalis L., 1766) breeding in the northern Gulf of Mexico. In Brown Pelicans, the post-egg-hatching phase imposes increased foraging demands on breeding adults relative to the prehatching phase. This study demonstrates that the progression of the breeding period affects the nature and intensity of the relationship between individual-based factors and movement patterns. In particular, birds in relatively lower condition traveled greater distances during foraging trips during the energetically demanding posthatching phase, but not during the incubation stage. Contrary to many seabird species studied to date, neither colony size nor sex appeared to affect Brown Pelican movement patterns. Our results suggest that nest stage is the most important factor influencing foraging movements, and that it may modulate relationships between condition and movement. More refined measures of body condition and foraging behavior will allow further insights into the movement ecology of this seabird.
Analysis of transient flow and starting pressure gradient of power-law fluid in fractal porous media
Authors: Tan Xiao-Hua , Li Xiao-Ping , Zhang Lie-Hui , Liu Jian-Yi , Cai Jianchao
Published: August 2014

A transient flow model for power-law fluid in fractal porous media is derived by combining transient flow theory with the fractal properties of tortuous capillaries. Pressure changes of transient flow for power-law fluid in fractal porous media are related to pore fractal dimension, tortuosity fractal dimension and the power-law index. Additionally, the starting pressure gradient model of power-law fluid in fractal porous media is established. Good agreement between the predictions of the present model and that of the traditional empirical model is obtained, the sensitive parameters that influence the starting pressure gradient are specified and their effects on the starting pressure gradient are discussed.
Surface defect gap solitons in optical lattices with nonlocal nonlinearity
Authors: Fang Limin , Gao Jie , Zhu Xing , Shi Zhiwei , Li Huagang
Published: August 2014

We show that stable surface fundamental defect solitons can exist in different gaps of an optical lattice with focusing nonlocal Kerr nonlinearity. For positive defect, solitons stably exist in the semi-infinite gap. For negative defect, solitons are stable in the semi-infinite gap and the first gap. Increasing the negative defect depth, the existent regions of defect solitons in the semi-infinite gap and in the first gap will be changed. The degree of the nonlocality will affect the profiles of these solitons.
INFLUENCE OF ELECTROPOLYMERIZATION METHOD ON MORPHOLOGIES AND CAPACITIVE PROPERTIES OF POLYPYRROLE FILMS GROWING ON SILICON
Authors: CHIKOUCHE IMENE , SAHARI ALI , ZOUAOUI AHMED
Published: August 2014

Two methods of Pyrrole electropolymerization were investigated to prepare polypyrrole films growing onto n-doped silicon n- Si (111): Polypyrrole films prepared by galvanostatic method exhibits toroidal morphology for thin films, and mixture of toroidal and globular morphologies for thick films. Polypyrrole films obtained from this method were characterized by lower surface roughness. Electropolymerization of pyrrole by potentiodynamic method provided Polypyrrole films with beans-like structures for both thin and thick films with high surface roughness. Due to their lower surface roughness, polypyrrole films produced by galvanostatic method exhibit high intensities in Raman spectroscopy. These polypyrrole films show better capacitive properties according to discharge test.
Buchsteiner loops: Associators and constructions
Authors: Drápal Aleš , Kinyon Michael
Published: August 2014

Let Q be a Buchsteiner loop. We describe the associator calculus in three variables, and show that |Q| ≥ 32 if Q is not conjugacy closed. We also show that |Q| ≥ 64 if there exists x ∈ Q such that x2 is not in the nucleus of Q. Furthermore, we describe a general construction that yields all proper Buchsteiner loops of order 32. Finally, we produce a Buchsteiner loop of order 128 that has both nilpotency class 3 and an abelian inner mapping group.
Few remarks on evolution algebras
Authors: Khudoyberdiyev A. Kh. , Omirov B. A. , Qaralleh Izzat
Published: August 2014

In this paper, we study some algebraic properties of evolution algebras. Moreover, we reduce the study of evolution algebras of permutations to two special types of evolution algebras, idempotents and absolute nilpotent elements of the algebra. We study three-dimensional evolution algebras whose each element of evolution basis has infinite period. In addition, for an evolution algebra with some properties we describe its associative enveloping algebra.
The Inclusion-Based LINMAP Method for Multiple Criteria Decision Analysis Within an Interval-Valued Atanassov's Intuitionistic Fuzzy Environment
Authors: Chen Ting-Yu
Published: August 2014

The purpose of this paper is to develop an inclusion-based LINMAP (i.e., Linear Programming Technique for Multidimensional Analysis of Preference) method for multiple criteria decision analysis that is based on interval-valued Atanassov's intuitionistic fuzzy sets. Using the inclusion comparison possibility in the interval-valued Atanassov's intuitionistic fuzzy context, an inclusion-based index of interval-valued Atanassov's intuitionistic fuzzy numbers is proposed that considers positive and negative ideals. An inclusion-based consistency index and an inclusion-based inconsistency index to measure the concordance and discordance, respectively, between paired comparison judgments are suggested. An inclusion-based LINMAP model is constructed using a linear programming technique to determine the optimal criterion weights and obtain the corresponding comprehensive inclusion-based index for each alternative. Then, the priority order of the alternatives can be acquired according to the comprehensive inclusion-based indices. The feasibility of the proposed method is illustrated using a practical problem that relates to the selection of bridge construction methods. A comparative analysis of other relevant decision-making methods is conducted to validate the effectiveness of the developed methodology.
PREDICTING FINANCIAL FAILURE OF THE TURKISH BANKS
Authors: DOĞANAY M. METE , CEYLAN NILDAĞ BAŞAK , AKTAŞ RAMAZAN
Published: August 2014

Banks are the most important financial institutions in Turkey because other financial institutions are not developed efficiently yet. Turkish banks experienced financial difficulties and a substantial amount of banks failed in the past. This event urged the government to initiate measures to prevent banks from getting into financial difficulties. As a result of these measures, Turkish banking system currently seems to be very attractive for the foreign investors willing to invest in this sector. One of the main concerns of the foreign investors is a possibility of a new banking crisis although it is very remote at this time. The purpose of this study is to develop early warning systems predicting the financial failure at least three years ahead of financial failure date.

A number of multivariate statistical models such as multiple regression, discriminant analysis, logit, probit are used. We found that the most appropriate model is logit. The significant variables obtained from the models explain very well the causes of the bank failures. Our models can be used to assist interested parties to predict the probability of financial failure of Turkish banks.
PREFERENCES, LÉVY JUMPS AND OPTION PRICING
Authors: MA CHENGHU
Published: August 2014

This paper derives an equilibrium formula for pricing European options and other contingent claims which allows incorporating impacts of several important economic variable on security prices including, among others, representative agent preferences, future volatility and rare jump events. The derived formulae is general and flexible enough to include some important option pricing formulae in the literature, such as Black–Scholes, Naik–Lee, Cox–Ross and Merton option pricing formulae. The existence of jump risk as a potential explanation of the moneyness biases associated with the Black–Scholes model is explored.
"HOW IS THE STOCK MARKET DOING?" USING ABSENCE OF ARBITRAGE TO MEASURE STOCK MARKET PERFORMANCE
Authors: POITRAS GEOFFREY , HEANEY JOHN
Published: August 2014

This paper provides a methodology for measuring stock market performance based on the restrictions provided by absence of arbitrage in security prices. Under the null hypothesis that the aggregate cumulative dividend-price process follows a geometric Brownian motion, a closed form related to the inter-temporal marginal rate of substitution is derived and empirically evaluated. The stock market performance measure is based on the level of risk adjustment required to compare the value of the stock index at the starting point with the cumulative interest rate deflated value at any given point in the time series. The paper concludes with empirical tests for the martingale property of the performance measure.