bluuebunny/crossref_metadata_2025_split huggingface dataset:
Near Constant Loss Dielectric Response in 2Bi2O3–B2O3 Glasses
Authors: Paramesh Gadige , Varma Kalidindi B. R. 
Published: July 2011

Electrical conduction and relaxation phenomena in bismuth borate glasses in the composition 2Bi2O3–B2O3 (Bi4B2O9) were investigated. Dielectric studies carried out on these glasses revealed near constant loss response in the 1 kHz–1 MHz frequency range at moderately high temperatures (300–450 K) associated with relatively low loss (tan δ = 0.006) and high dielectric constant (εr′ = 37) at 1 kHz, 300 K. The variation in AC conductivity with temperature at different frequencies showed a cross over from near constant loss response characterized by local ion vibration within the potential well to universal Jonscher's power law dependence triggered by ion hopping between potential wells or cages. Thermal activation energy for single potential well was found to be 0.48 ± 0.05 eV from cross over points. Ionic conduction and relaxation processes were rationalized by modulus formalism. The promising dielectric properties (relatively high εr′ and low tan δ) of the present glasses were attributed to high density (93% of its crystalline counterpart), high polarizability, and low mobility associated with heavy metal cations, Bi3+.
Effects of flunixin meglumine on the recovery of ischaemic equine colonic mucosain vitro
Authors: MORTON A. J. , GROSCHE A. , MATYJASZEK S. A. , POLYAK M. M. R. , FREEMAN D. E. 
Published: July 2011

SummaryReasons for performing study:The effects of prostaglandins and nonsteroidal anti‐inflammatory drugs (NSAIDs) on repair of equine intestinal mucosa are important since most horses with gastrointestinal diseases are routinely treated with NSAIDs, such as flunixin meglumine (FM), and these drugs can be toxic to equine gastrointestinal mucosa.Hypothesis:Flunixin meglumine would not affect recovery of equine colonic mucosain vitro, 18 h after a reversible ischaemic injury.Methods:In 14 anaesthetised horses, a segment of pelvic flexure was subjected to 2 h of ischaemia and the horses were allowed to recover for 18 h. Seven horses received normal saline and 7 received FM, 1.1 mg/kg bwt i.v., at the end of ischaemia and 12 h later. Colonic mucosa was harvested during a second anaesthesia, 18 h after recovery from ischaemia and then horses were subjected to euthanasia. Transepithelial electrical resistance (TER) and transepithelial flux of tritiated mannitol were used to measure mucosal permeability during 4 h of incubation in Ussing chambers, with the followingin vitrotreatments: 1) no addition, 2) FM 14 µmol/l as powder, 3) FM 14 µmol/l in injectable form and 4) diluent for injectable FM. Histomorphological changes were assessed by light microscopy.Results:There were no significant differences in any of the measurements between saline and FM treated horses. The mucosal height of the ischaemic FM tissues incubated in diluent was significantly decreased compared to the nonischaemic tissues.Conclusions:Flunixin meglumine did not adversely affect barrier integrity in ischaemic equine colonic mucosa.
Investigation of the effect of pasture and stable management on large intestinal motility in the horse, measured using transcutaneous ultrasonography
Authors: WILLIAMS S. , TUCKER C. A. , GREEN M. J. , FREEMAN S. L. 
Published: July 2011

SummaryReason for performing study:Management regimes have been identified as risk factors for equine intestinal motility disorders. However, it is not known how management factors affect gastrointestinal motility.Hypothesis:Large intestinal motility was similar in horses on a stabled and a pastured management regime.Objective:To investigate the effect of 2 different management regimes on large intestinal motility assessed with ultrasonography.Methods:A within‐subjects crossover design was used to compare large intestinal motility between a stabled and a pastured regime in 16 working horses.Group Awas managed under a standardised stabled regime throughout the study.Group Bwas maintained at pasture for the first monitoring phase and then transferred to the stabled regime for the second monitoring phase. Motility of the caecum, sternal flexure and aboral left ventral colon (contractions/min) was measured twice daily for 2 consecutive days using transcutaneous ultrasonography. Mean values for each management regime were pooled for analysis using multilevel statistical modelling.Results:Significant variables identified by the model included: time of day, region of intestine, management regime, and combination of region of intestine and management regime. Motility assessed by ultrasound was significantly lower in stabled horses compared to pasture‐kept horses. Intestinal motility for caecum was 1.7 ± 0.3 contractions/min (pastured = 2.0, stabled = 1.4), sternal flexure was 1.6 ± 0.2 contractions/min (mean (pastured = 1.7, stabled = 1.5), and left ventral colon was 0.8 ± 0.3 contractions/min (pastured = 1.0, stabled = 0.7).Conclusions:The null hypothesis was disproven. Large intestinal motility assessed by ultrasound was significantly reduced in stabled horses compared to pastured horses. This effect was most marked in the aboral left ventral colon.Potential relevance:This study has demonstrated a possible mechanism for the increased risk of large intestinal impactions in stabled horses.
Surgical drainage and post operative lavage of large abdominal abscesses in six mature horses
Authors: MAIR T. S. , SHERLOCK C. E. 
Published: July 2011

SummarySix mature horses with large abdominal abscesses (defined as an abscess >15–20 cm in at least one dimension) were treated by surgical drainage and post operative lavage. The abscess was associated with previous intestinal surgery in one horse, and withStreptococcus equispp.equiinfection in the other 5. A Foley catheter was used to drain and lavage the abscess in all cases. The abscess was accessed by a ventral midline laparotomy in 5 cases and by standing flank laparoscopy in one. Two horses were subjected to euthanasia within 7 days due to persistent or recurrent colic. The other 4 horses survived. Lavage of the abscess was continued for a median time of 19 days. Antibacterial therapy was continued until the plasma fibrinogen concentration was normal (median 47 days). Follow‐up information was obtained at a median of 1.8 years. All 4 horses were alive at the time of follow‐up; 2 horses had suffered one or more bouts of colic that had responded to medical treatment.
Application of the lactose13C‐ureide breath test for measurement of equine orocaecal transit time
Authors: SUTTON D. G. M. , PRESTON T. , LOVE S. 
Published: July 2011

SummaryReasons for performing study:Application of the lactose13C‐ureide breath test (LUBT) for measurement of equine orocaecal transit time (OCTT) has not been reported previously. The ability to assess OCTT noninvasively, and to investigate its relationship to gastric emptying rate and small intestinal transit, would be of both clinical and research value.Objectives:1) Assessment of the LUBT in healthy horses, with comparison of induced versus noninduced test protocols. 2) Application of a new dual stable isotope breath test (lactose13C‐ureide and13C‐octanoic acid) for gastrointestinal transit measurement.Hypothesis:The LUBT will allow quantification of equine OCTT, and test efficacy will be enhanced by prior administration of lactose12C‐ureide as shownin vitro. The dual tracer breath test will permit simultaneous measurement of gastric emptying, OCTT and small bowel transit times.Methods:Induced and noninduced LUBTs were performed in 3 healthy mature horses in randomised order using a standard test meal and protocol. Combined LUBT and13C‐octanoic acid breath tests (13C‐OABT) were performed in 4 individuals on 4 occasions at weekly intervals. Expiratory isotopic recovery was modelled to allow generation of gastric emptying data, small bowel transit times and caecal transit parameters.Results:The induction protocol for the LUBT increased the rate and magnitude of expiratory13CO2significantly. Mean ± s.d. values for OCTT, caecal lag phase (tlag) and caecal t1/2using the induced LUBT were 3.24 ± 0.65 h, 5.62 ± 1.22 h and 6.31 ± 1.21 h, respectively. Dual stable isotope tests resulted in the production of 2 discrete peaks in expiratory13CO2in 15/16 tests from which gastric t1/2, OCTT and small bowel transit (SBT) parameters could be calculated.Conclusions:The induced LUBT provides a reliable noninvasive measure of equine OCTT and can be paired with the13C‐OABT to provide further information about small intestinal motility.
Far-Field Radiation of Tip Aerodynamic Sound Sources in Axial Fans
Fitted With Passive Noise Control Features
Authors: Bianchi Stefano , Corsini Alessandro , Rispoli Franco , Sheard Anthony G. 
Published: July 2011

Abstract
This study investigates the causal relationship between flow aerodynamics and radiated noise in low-speed axial fans. Using blades with three distinctive tip configurations, including two that were developed with a view to reducing noise emissions, the pressure fluctuations of the exhaust flow in the near field are correlated with the noise measured in the far field in an anechoic chamber. By varying the far-field microphone’s azimuthal position, the study investigates the source signatures and directivity of noise sources distributed along the blade span. Several distinctive features in the noise directivity pattern are identified and correlated with the noise sources of aerodynamic origin dissected along the blade span. Utilizing the directional far-field autospectra of the three blade configurations in combination with the near-field/far-field cross-spectra, the emission characteristics of the aerodynamic sources are analyzed and their roles with respect to the overall acoustic signature of the fan are discussed. It is apparent that the ability to decompose the output of the aerodynamic noise sources in the near field is a useful tool in designing fans to achieve desirable low-noise targets. The results confirm that the tip-flow appendages influence the noise radiation pattern for the investigated family of fans. These phenomena are linked with the control of aerodynamic noise sources related to the tip-leakage vortex and the hub corner separation.
Susceptibility of Pneumocystis to Echinocandins in Suspension and Biofilm Cultures
Authors: Cushion Melanie T. , Collins Margaret S. 
Published: July 2011

ABSTRACT

The targeted inhibition of cyst but not trophic development by anidulafungin, caspofungin, and micafungin on
Pneumocystis murina
and
Pneumocystis carinii
in rodent models of
Pneumocystis carinii
pneumonia (PCP) was recently reported by us (M. T. Cushion et al., PLoS One 5:e8524, 2010). To better understand the effects of echinocandins on
P. carinii
, the same three compounds were evaluated in standard suspension and biofilm cultures supplemented with various concentrations of sera using the measurement of ATP as the indicator. In suspension cultures with 1 and 5% serum, anidulafungin was the most active compound but 10 and 20% serum abrogated the efficacy of all three echinocandins. Established biofilm cultures that included both the nonadherent and adherent phases were more resistant to micafungin than caspofungin regardless of serum concentration, while anidulafungin had significant activity at 1 and 5% serum concentrations. Nascent biofilms were mostly affected by anidulafungin in 1 and 5% serum, but none of the compounds showed significant activity in 20% serum. We show for the first time that (i) echinocandins differ in their abilities to deplete the ATP of
Pneumocystis
in biofilms and in suspension cultures, (ii) this variability mostly reflected the reported efficacies in animal models of infection, and (iii) high serum levels decreased the anti-
Pneumocystis
activities of the echinocandins in both
in vitro
systems.
Characterizing Vancomycin-Resistant Enterococcus Strains with Various Mechanisms of Daptomycin Resistance Developed in an
In Vitro
Pharmacokinetic/Pharmacodynamic Model
Authors: Steed Molly E. , Vidaillac Celine , Rose Warren E. , Winterfield Patricia , Kaatz Glenn W. , Rybak Michael J. 
Published: July 2011

ABSTRACT

Two daptomycin (DAP) regimens were evaluated in a pharmacokinetic/pharmacodynamic (PK/PD) model, and the mutants recovered were examined for changes in phenotypic characteristics. Three
Enterococcus faecium
strains (vancomycin-resistant
Enterococcus
[VRE] ATCC 51559, VRE 12311, and VRE SF 12047) were utilized in a 7-day, 1-compartment
in vitro
PK/PD model. The simulated dosing regimens were DAP at 6 mg/kg/day (free
C
max
[
fC
max
] = 7.9 μg/ml, half-life [
t
1/2
] = 8 h) and DAP at 10 mg/kg/day (
fC
max
= 13.17 μg/ml,
t
1/2
= 8 h). Samples were plated daily on Mueller-Hinton agar containing DAP at 16 μg/ml and 50 mg/liter Ca
2+
to assess the emergence of DAP resistance. For each strain, the mutant with the highest DAP MIC was then evaluated for changes in relative surface charge, cell wall thickness, and cytoplasmic membrane depolarization induced by DAP. The initial DAP MICs were 4 μg/ml for all 3 strains. A dose-dependent response and regrowth were observed for DAP 6 mg/kg/day and DAP 10 mg/kg/day against all 3 strains. Mutants of VRE ATCC 51559 (MIC = 128 and 64 μg/ml) and VRE 12311 (MIC = 256 and 32 μg/ml) were recovered from the DAP 6 mg and DAP 10 mg regimen, respectively. For VRE SF 12047, a mutant (MIC = 64 μg/ml) was recovered from the DAP 6 mg model. All mutants displayed an increase in relative surface charge compared to those of their respective parent strains. The DAP-resistant mutants displayed a 43 to 58% increase in cell wall thickness (
P
< 0.0001), while DAP membrane depolarization decreased by 53 to 65% compared to that of the susceptible strains. VRE with DAP resistance displayed increased surface charge, increased cell wall thickness, and decreased depolarization induced by DAP, consistent with previous observations in
Staphylococcus aureus
with reduced DAP susceptibility. Further characterization of DAP-resistant VRE is warranted.
Genetic Diversity of Tn
916
-Related Transposons among Drug-Resistant Streptococcus pneumoniae Isolates Colonizing Healthy Children in Venezuela
Authors: Quintero Beatríz , Araque María , van der Gaast-de Jongh Christa , Hermans Peter W. M. 
Published: July 2011

ABSTRACT

Among a collection of 48 multidrug-resistant pneumococcal strains colonizing healthy children in a small municipality of Mérida, Venezuela, we identified sequence types (STs) related to a variety of internationally spreading drug-resistant clones, as well as ST135, thus far isolated only in Europe. The clones invariably harbored one or more of the Tn
916
-related transposons Tn
3872
, Tn
5253
, Tn
6002
, Tn
2009
, and Tn
2010
. Finally, our data suggest both structural rearrangements in certain transposons and occurrence of novel transposable elements.
Intrinsic Epidemicity of Streptococcus pneumoniae Depends on Strain Serotype and Antibiotic Susceptibility Pattern
Authors: Domenech de Cellès Matthieu , Opatowski Lulla , Salomon Jérôme , Varon Emmanuelle , Carbon Claude , Boëlle Pierre-Yves , Guillemot Didier 
Published: July 2011

ABSTRACT

Streptococcus pneumoniae
is a major cause of invasive diseases worldwide. It spreads through an interindividual transmission, followed by usually harmless colonization of the host. Possible transmission differences reflecting intrinsic strain features (e.g., serotype and antibiotic susceptibility) have been little studied so far. In this study, we used epidemiological data from an interventional trial of
S. pneumoniae
carriage among kindergartners and developed a mathematical model to estimate the transmission parameters of the different strains isolated during that study. We found small but significant transmissibility differences between the observed serotypes: serotypes 3, 6A, and 19A were found to be the most epidemic, while serotypes 23F, 9V, and 14 were the least epidemic. Further analysis indicated that, within a serotype, susceptible and resistant strains had different abilities to be transmitted. Susceptible-to-resistant transmission rate ratios were computed for five serotypes; susceptible strains were significantly more epidemic than resistant strains for serotypes 6A (mean, 1.02) and 19F (1.05). Serotype 19A resistant strains were not outcompeted by susceptible strains (0.97). Nonsignificant trends were observed for serotypes 6B (1.01) and 15A (0.98). Our results support the existence of heterogeneous abilities of the different serotypes for host-to-host transmission. They also suggest that antibiotic susceptibility within a serotype affects this transmissibility. We conclude that pneumococcal strains should not be considered equally at-risk in terms of transmission. Further quantification of strain-specific epidemic potential is needed, especially in a context of extensive use of conjugate vaccines with the aim of preventing pneumococcal infections.
OXA-198, an Acquired Carbapenem-Hydrolyzing Class D β-Lactamase from Pseudomonas aeruginosa
Authors: El Garch Farid , Bogaerts Pierre , Bebrone Carine , Galleni Moreno , Glupczynski Youri 
Published: July 2011

ABSTRACTA carbapenem-resistantPseudomonas aeruginosastrain (PA41437) susceptible to expanded-spectrum cephalosporins was recovered from several consecutive lower-respiratory-tract specimens of a patient who developed a ventilator-associated pneumonia while hospitalized in an intensive care unit. Cloning experiments identified OXA-198, a new class D β-lactamase which was weakly related (less than 45% amino acid identity) to other class D β-lactamases. Expression inEscherichia coliTOP10 and inP. aeruginosaPAO1 led to transformants that were resistant to ticarcillin and showed reduced susceptibility to carbapenems and cefepime. TheblaOXA-198gene was harbored by a class 1 integron carried by a ca. 46-kb nontypeable plasmid. This study describes a novel class D β-lactamase involved in carbapenem resistance inP. aeruginosa.
CMX001 Potentiates the Efficacy of Acyclovir in Herpes Simplex Virus Infections
Authors: Prichard Mark N. , Kern Earl R. , Hartline Caroll B. , Lanier E. Randall , Quenelle Debra C. 
Published: July 2011

ABSTRACT
Although acyclovir (ACV) has proven to be of value in the therapy of certain herpes simplex virus (HSV) infections, there is a need for more effective therapies, particularly for serious infections in neonates and immunocompromised individuals, where resistance to this drug can be problematic. CMX001 is an orally bioavailable lipid conjugate of cidofovir that is substantially less nephrotoxic than the parent drug and has excellent antiviral activity against all the human herpesviruses. This compound retains full antiviral activity against ACV-resistant laboratory and clinical isolates. The combined efficacy of CMX001 and ACV was evaluated in a new real-time PCR combination assay, which demonstrated that the combination synergistically inhibited the replication of HSV in cell culture. This was also confirmed in murine models of HSV infection, where the combined therapy with these two drugs synergistically reduced mortality. These results suggest that CMX001 may be effective in the treatment of ACV-resistant HSV infections and as an adjunct therapy in individuals with suboptimal responses to ACV.
Cyclopropavir Inhibits the Normal Function of the Human Cytomegalovirus UL97 Kinase
Authors: James Scott H. , Hartline Caroll B. , Harden Emma A. , Driebe Elizabeth M. , Schupp James M. , Engelthaler David M. , Keim Paul S. , Bowlin Terry L. , Kern Earl R. , Prichard Mark N. 
Published: July 2011

ABSTRACT
Cyclopropavir (CPV) is active against human cytomegalovirus (CMV), as well as both variants of human herpesvirus 6 and human herpesvirus 8. The mechanism of action of CPV against CMV is similar to that of ganciclovir (GCV) in that it is phosphorylated initially by the CMV UL97 kinase, resulting in inhibition of viral DNA synthesis. Resistance to CPV maps to the UL97 kinase but is associated primarily with H520Q mutations and thus retains good antiviral activity against most GCV-resistant isolates. An examination of CMV-infected cultures treated with CPV revealed unusual cell morphology typically associated with the absence of UL97 kinase activity. A surrogate assay for UL97 kinase activity confirmed that CPV inhibited the activity of this enzyme and that its action was similar to the inhibition seen with maribavir (MBV) in this assay. Combination studies using real-time PCR indicated that, like MBV, CPV also antagonized the efficacy of GCV and were consistent with the observed inhibition of the UL97 kinase. Deep sequencing of CPV-resistant laboratory isolates identified a frameshift mutation in UL27, presumably to compensate for a loss of UL97 enzymatic activity. We conclude that the mechanism of action of CPV against CMV is complex and involves both the inhibition of DNA synthesis and the inhibition of the normal activity of the UL97 kinase.
Heat-Labile- and Heat-Stable-Toxoid Fusions (LT
R192G
-STa
P13F
) of Human Enterotoxigenic Escherichia coli Elicit Neutralizing Antitoxin Antibodies
Authors: Liu Mei , Ruan Xiaosai , Zhang Chengxian , Lawson Steve R. , Knudsen David E. , Nataro James P. , Robertson Donald C. , Zhang Weiping 
Published: July 2011

ABSTRACT

Enterotoxigenic
Escherichia coli
(ETEC) strains are a major cause of diarrheal disease in humans and animals. Adhesins and enterotoxins, including heat-labile (LT) and heat-stable (STa) toxins, are the key virulence factors. Antigenic adhesin and LT antigens have been used in developing vaccines against ETEC diarrhea. However, STa has not been included because of its poor immunogenicity and potent toxicity. Our recent study showed that porcine-type STa toxoids became immunogenic and elicited neutralizing anti-STa antibodies after being genetically fused to a full-length porcine-type LT toxoid, LT
R192G
(W. Zhang et al., Infect. Immun. 78:316-325, 2010). In this study, we mutated human-type LT and STa genes, which are highly homologous to porcine-type toxin genes, for a full-length LT toxoid (LT
R192G
) and a full-length STa toxoid (STa
P13F
) and genetically fused them to produce LT
192
-STa
13
toxoid fusions. Mice immunized with LT
192
-STa
13
fusion antigens developed anti-LT and anti-STa IgG (in serum and feces) and IgA antibodies (in feces). Moreover, secretory IgA antibodies from immunized mice were shown to neutralize STa and cholera toxins in T-84 cells. In addition, we fused the STa
13
toxoid at the N terminus and C terminus, between the A1 and A2 peptides, and between the A and B subunits of LT
192
to obtain different fusions in order to explore strategies for enhancing STa immunogenicity. This study demonstrated that human-type LT
192
-STa
13
fusions induce neutralizing antitoxin antibodies and provided important information for developing toxoid vaccines against human ETEC diarrhea.