1,364 research outputs found
Prevalence, diversity and transferability of the Tn916-Tn1545 family ICE in oral streptococci
Background: The Tn916-Tn1545 family of Integrative Conjugative Elements (ICE) are mobile genetic elements (MGEs) that play a role in the spread of antibiotic resistance genes. The Tn916 harbors the tetracycline resistance gene tet(M) and it has been reported in various bacterial species. The increase in the levels of tetracycline resistance among oral streptococci is of great concern primarily due to the abundance of these species in the oral cavity and their ability to act as reservoirs for antibiotic resistance genes.
Methods: In the current study, we screened 100 Norwegian clinical oral streptococcal isolates for the presence and diversity of the Tn916-Tn1545 family. In addition, we investigated the transferability the elements, and the associated transfer frequencies.
Results: We observed that 21 isolates harboured the Tn916-Tn1545 family and that two of these elements were the novel Tn6815 and Tn6816. The most prevalent member of the Tn916 -Tn1545 family observed in the Norwegian clinical oral streptococcal isolates was the wild type Tn916.Conclusion: The detection of other members of this family of ICE and varying transfer frequencies suggests high versatility of the Tn916 element in oral streptococci in Norway
NRG/RTOG 0837: Randomized, phase II, double-blind, placebo-controlled trial of chemoradiation with or without cediranib in newly diagnosed glioblastoma
BACKGROUND: A randomized, phase II, placebo-controlled, and blinded clinical trial (NCT01062425) was conducted to determine the efficacy of cediranib, an oral pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor, versus placebo in combination with radiation and temozolomide in newly diagnosed glioblastoma.
METHODS: Patients with newly diagnosed glioblastoma were randomly assigned 2:1 to receive (1) cediranib (20 mg) in combination with radiation and temozolomide; (2) placebo in combination with radiation and temozolomide. The primary endpoint was 6-month progression-free survival (PFS) based on blinded, independent radiographic assessment of postcontrast T1-weighted and noncontrast T2-weighted MRI brain scans and was tested using a 1-sided
RESULTS: One hundred and fifty-eight patients were randomized, out of which 9 were ineligible and 12 were not evaluable for the primary endpoint, leaving 137 eligible and evaluable. 6-month PFS was 46.6% in the cediranib arm versus 24.5% in the placebo arm (
CONCLUSIONS: This study met its primary endpoint of prolongation of 6-month PFS with cediranib in combination with radiation and temozolomide versus placebo in combination with radiation and temozolomide. There was no difference in overall survival between the 2 arms
The validity and responsiveness of the ICECAP-A capability-wellbeing measure in women with irritative lower urinary tract symptoms
PURPOSE: A desire to incorporate broader aspects of well-being in health economic evaluations has led to the development of the ICEpop CAPability measure for Adults (ICECAP-A). The ICECAP-A draws upon Amartya Sen's capability approach and conceptualises well-being as the capability to achieve Stability, Attachment, Autonomy, Achievement, and Enjoyment. The aim of this study was to assess the psychometric performance of the ICECAP-A in a context where patient outcomes can extend beyond health-related quality of life. METHODS: Longitudinal data were collected for 478 women with symptoms of urinary frequency and urgency, with or without incontinence. Women were recruited across 22 hospitals in the UK and had a mean age of 55 (SD 14). The psychometric performance of the measure was evaluated in relation to the EuroQol Five-Dimension Questionnaire (EQ-5D-3L) and the International Consultation on Incontinence Questionnaire for Overactive Bladder (ICIQ-OAB) and involved an assessment of acceptability, construct validity, and responsiveness using parametric and nonparametric methods. RESULTS: ICECAP-A showed good convergence with the ICIQ-OAB with 20 out of 22 expected patterns of relationship confirmed. Findings suggested that the ICECAP-A has better discriminative properties than EQ-5D-3L and as good as those of the ICIQ-OAB, confirming expected associations with clinical and demographic factors. The ICECAP-A was more responsive than EQ-5D-3L and ICIQ-OAB to deteriorations of clinical symptoms. Improvements in symptoms were not valued as highly as deteriorations by either ICECAP-A or EQ-5D-3L. CONCLUSIONS: The ICECAP-A is a valid and responsive measure capturing broad emotional and practical impacts of urinary symptoms on women's well-being and could be considered for use in economic evaluations in this context
Brand Salience and Brand Differentiation of the Florida Forest Service
This study addressed the themes affecting the brand salience and brand differentiation of the Florida Forest Service (FFS). Six focus groups were conducted at different locations in Florida. FFS suffered from a lack of brand salience and differentiation. Brand salience is the extent to which a brand comes to mind for the public. Brand differentiation is the extent to which a brand separates itself from competitors in the public’s perceptions. Three themes emerged that affected brand salience: the importance of forests, brand identifiers, and external communications. Two themes emerged for affecting brand differentiation: forest and natural resources organizations and communications. The following recommendations were made for public organizations: ensure the organization’s brand is present in the public’s external environment, create salient messages and brand identifiers, test messages and brand identifiers prior to implementation, and consistently use messages and brand identifiers. The following recommendations were made for future research: replicate the research to other settings to address the transferability of the findings, conduct quantitative research to address brand salience and differentiation for public organizations in a generalizable manner, and research perceptions of public organizations’ communications
The 2001 Superoutburst of WZ Sagittae
We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23-year slumber at V=15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ~1 mag amplitude and 2 day recurrence time; these “echo outbursts” are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: a strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) d, 0.92(8)% longer than Porb. The latter endured for at least 90 days, although probably mutating into a “late” superhump with a slightly longer mean period [0.05736(5) d]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: the orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk’s apsidal precession. Long time series reveal an intricate fine structure, with ~20 incommensurate frequencies. Essentially all components occurred at a frequency nωo–mΩ, with m=1, ..., n. But during its first week, the common superhump showed primary components at nωo–Ω, for n=1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m=1 consistently); a month later, the dominant power shifted to components with m=n–1. This may arise from a shift in the disk’s spiral-arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are red-shifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 c/day suggests the possibility of a retrograde precession at a different rate, probably N=0.13±0.02 c/day. The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly aslarge as the white dwarf’s Roche lobe. The hotspot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption. (Refer to PDF file for exact formulas)
Guest charges in an electrolyte: renormalized charge, long- and short-distance behavior of the electric potential and density profile
We complement a recent exact study by L. Samaj on the properties of a guest
charge immersed in a two-dimensional electrolyte with charges . In
particular, we are interested in the behavior of the density profiles and
electric potential created by the charge and the electrolyte, and in the
determination of the renormalized charge which is obtained from the
long-distance asymptotics of the electric potential. In Samaj's previous work,
exact results for arbitrary coulombic coupling were obtained for a
system where all the charges are points, provided and .
Here, we first focus on the mean field situation which we believe describes
correctly the limit but large. In this limit we can
study the case when the guest charge is a hard disk and its charge is above the
collapse value . We compare our results for the renormalized charge
with the exact predictions and we test on a solid ground some conjectures of
the previous study. Our study shows that the exact formulas obtained by Samaj
for the renormalized charge are not valid for , contrary to a
hypothesis put forward by Samaj. We also determine the short-distance
asymptotics of the density profiles of the coions and counterions near the
guest charge, for arbitrary coulombic coupling. We show that the coion density
profile exhibit a change of behavior if the guest charge becomes large enough
(). This is interpreted as a first step of the counterion
condensation (for large coulombic coupling), the second step taking place at
the usual Manning--Oosawa threshold
A New Solution to the Plasma Starved Event Horizon Magnetosphere: Application to the Forked Jet in M87
Very Long Baseline Interferometry observations at 86 GHz reveal an almost
hollow jet in M87 with a forked morphology. The detailed analysis presented
here indicates that the spectral luminosity of the central spine of the jet in
M87 is a few percent of that of the surrounding hollow jet from the central black hole. Furthermore, recent jet models in
indicate that a hollow "tubular" jet can explain a wide range of plausible
broadband spectra originating from jetted plasma located within of the central black hole, including the 230 GHz correlated flux
detected by the Event Horizon Telescope. Most importantly, these hollow jets
from the inner accretion flow have an intrinsic power capable of energizing the
global jet out to kiloparsec scales. Thus motivated, this paper considers new
models of the event horizon magnetosphere (EHM) in low luminosity accretion
systems. Contrary to some models, the spine is not an invisible powerful jet.
It is an intrinsically weak jet. In the new EHM solution, the accreted poloidal
magnetic flux is weak and the background photon field is weak. It is shown how
this accretion scenario naturally results in the dissipation of the accreted
poloidal magnetic flux in the EHM not the accumulation of poloidal flux
required for a powerful jet. The new solution indicates less large scale
poloidal magnetic flux (and jet power) in the EHM than in the surrounding
accretion flow and cannot support significant EHM driven jets.Comment: To appear in Astronomy and Astrophysics. Revision fixes typos found
during proof
Determination of copy number and circularization ratio of Tn916-Tn1545 family of conjugative transposons in oral streptococci by droplet digital PCR
Background: Tn916 and Tn1545 are paradigms of a large family of related, broad host range, conjugative transposons that are widely distributed in bacteria and contribute to the spread of antibiotic resistance genes (ARGs). Variation in the copy number (CN) of Tn916-Tn1545 elements and the circularization ratio (CR) may play an important role in propagation of ARGs carried by these elements.
Objectives and Design: In this study, the CN and CR of Tn916-Tn1545 elements in oral streptococci were determined using droplet digital PCR (ddPCR). In addition, we investigated the influence of tetracycline on the CR of Tn916-Tn1545 elements.
Results: The ddPCR assay designed in this study is a reliable way to rapidly determine CN and CR of Tn916-Tn1545 elements.
Conclusions: Our data also suggest that Tn916-Tn1545 elements are generally stable without selective pressure in the clinical oral Streptococcus strains investigated in this study
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