Induction heating for eradicating Staphylococcus epidermidis from biofilm

AimsInduction heating is a noninvasive, nonantibiotic treatment modality that can potentially be used to cause thermal damage to the bacterial biofilm on the metal implant surface. The purpose of this study was to determine the effectiveness of induction heating on killing Staphylococcus epidermidis from biofilm and to determine the possible synergistic effect of induction heating and antibiotics.MethodsS. epidermidis biofilms were grown on titanium alloy (Ti6Al4V) coupons for 24 hours (young biofilm) and seven days (mature biofilm). These coupons with biofilm were heated to temperatures of 50 degrees C, 55 degrees C, 60 degrees C, 65 degrees C, 70 degrees C, 80 degrees C, and 90 degrees C for 3.5 minutes and subsequently exposed to vancomycin and rifampicin at clinically relevant concentrations.ResultsFor the young biofilm, total eradication was observed at 65 degrees C or higher for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. For the mature biofilm, total eradication was observed at 60 degrees C for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. Total eradication was also observed at 60 degrees C for 3.5 minutes followed by 24 hours of vancomycin 1 mg/l and rifampicin 1 mg/l followed by anotherthermal shock of 60 degrees C for 3.5 minutes (two thermal shocks).ConclusionInduction heating of Ti6Al4V coupons is effective in reducing bacterial load in vitro for S. epidermidis biofilms. Induction heating and antibiotics have a synergistic effect resulting in total eradication of the biofilm at 60 degrees C or higher for clinically relevant concentrations of vancomycin and rifampicin.Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Wide binaries as a critical test of Classical Gravity

Modified gravity scenarios where a change of regime appears at acceleration scales $a<a_{0}$ have been proposed. Since for $1 M_{\odot}$ systems the acceleration drops below $a_{0}$ at scales of around 7000 AU, a statistical survey of wide binaries with relative velocities and separations reaching $10^{4}$ AU and beyond should prove useful to the above debate. We apply the proposed test to the best currently available data. Results show a constant upper limit to the relative velocities in wide binaries which is independent of separation for over three orders of magnitude, in analogy with galactic flat rotation curves in the same $a<a_{0}$ acceleration regime. Our results are suggestive of a breakdown of Kepler's third law beyond $a \approx a_{0}$ scales, in accordance with generic predictions of modified gravity theories designed not to require any dark matter at galactic scales and beyond.Comment: accepted for publication in EPJ

The bacterial gut microbiota of adult patients infected, colonized or noncolonized by clostridioides difficile

Gut microbiota composition in patients with Clostridioides difficile colonization is not well investigated. We aimed to identify bacterial signatures associated with resistance and susceptibility to C. difficile colonization (CDC) and infection (CDI). Therefore, gut microbiota composition from patients with CDC (n = 41), with CDI (n = 41), and without CDC (controls, n = 43) was determined through 16S rRNA gene amplicon sequencing. Bacterial diversity was decreased in CDC and CDI patients (p < 0.01). Overall microbiota composition was significantly different between control, CDC, and CDI patients (p = 0.001). Relative abundance of Clostridioides (most likely C. difficile) increased stepwise from controls to CDC and CDI patients. In addition, differential abundance analysis revealed that CDI patients' gut microbiota was characterized by significantly higher relative abundance of Bacteroides and Veillonella than CDC patients and controls. Control patients had significantly higher Eubacterium hallii and Fusicatenibacter abundance than colonized patients. Network analysis indicated that Fusicatenibacter was negatively associated with Clostridioides in CDI patients, while Veillonella was positively associated with Clostridioides in CDC patients. Bacterial microbiota diversity decreased in both CDC and CDI patients, but harbored a distinct microbiota. Eubacterium hallii and Fusicatenibacter may indicate resistance against C. difficile colonization and subsequent infection, while Veillonella may indicate susceptibility to colonization and infection by C. difficile.Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Simulated Optimisation of Disordered Structures with negative Poisson’s ratios

Copyright © 2009 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Mechanics of Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanics of Materials, Vol. 41 Issue 8 (2009). DOI: 10.1016/j.mechmat.2009.04.008Two-dimensional regular theoretical units that give a negative Poisson’s ratio (NPR) are well documented and well understood. Predicted mechanical properties resulting from these models are reasonably accurate in two dimensions but fall down when used for heterogeneous real-world materials. Manufacturing processes are seldom perfect and some measure of heterogeneity is therefore required to account for the deviations from the regular unit cells in this real-life situation. Analysis of heterogeneous materials in three dimensions is a formidable problem; we must first understand heterogeneity in two dimensions. This paper approaches the problem of finding a link between heterogeneous networks and its material properties from a new angle. Existing optimisation tools are used to create random two-dimensional topologies that display NPR, and the disorder in the structure and its relationship with NPR is investigated

Centrality dependence of charged-particle pseudorapidity distributions from d+Au collisions at sqrt(s_{NN})=200 GeV

Charged-particle pseudorapidity densities are presented for the d+Au reaction at sqrt{s_{NN}}=200 GeV with -4.2 <= eta <= 4.2$. The results, from the BRAHMS experiment at RHIC, are shown for minimum-bias events and 0-30%, 30-60%, and 60-80% centrality classes. Models incorporating both soft physics and hard, perturbative QCD-based scattering physics agree well with the experimental results. The data do not support predictions based on strong-coupling, semi-classical QCD. In the deuteron-fragmentation region the central 200 GeV data show behavior similar to full-overlap d+Au results at sqrt{s_{NN}}=19.4 GeV.Comment: 4 pages, 3figures; expanded discussion of uncertainties; added 60-80% centrality range; added additional discussion on centrality selection bia

Scanning the phases of QCD with BRAHMS

BRAHMS has the ability to study relativistic heavy ion collisions from the final freeze-out of hadrons all the way back to the initial wave-function of the gold nuclei. This is accomplished by studying hadrons with a very wide range of momenta and angles. In doing so we can scan various phases of QCD, from a hadron gas, to a quark gluon plasma and perhaps to a color glass condensate.Comment: 8 pages, 6 figures, proceedings of plenary talk at Quark Matter 2004 conferenc