Hydrogen Peroxide Wound Irrigation in Orthopaedic Surgery.

As the burden of deep hardware infections continues to rise in orthopaedics, there is increasing interest in strategies for more effective debridement of colonized tissues and biofilm. Hydrogen peroxide has been used medically for almost a century, but its applications in orthopaedic surgery have yet to be fully determined. The basic science and clinical research on the antiseptic efficacy of hydrogen peroxide have demonstrated its efficacy against bacteria, and it has demonstrated potential synergy with other irrigation solutions such as chlorhexidine and povidone-iodine. While hydrogen peroxide is effective in infection reduction, there are concerns with wound healing, cytotoxicity, and embolic phenomena, and we recommend against hydrogen peroxide usage in the treatment of partial knee replacements, hemiarthroplasties, or native joints. Additionally, due to the potential for oxygen gas formation, hydrogen peroxide should not be used in cases of dural compromise, when pressurizing medullary canals, or when irrigating smaller closed spaces to avoid the possibility of air embolism. Finally, we present our protocol for irrigation and debridement and exchange of modular components in total joint arthroplasty, incorporating hydrogen peroxide in combination with povidone-iodine and chlorhexidine

Accessing directly the strange quark content of the proton at HERA

We investigate a double-spin asymmetry for the semi-inclusive $\Lambda$ hyperon production in the longitudinally deep inelastic lepton-proton scattering, the sign of which can provide us with important information about the strange quark helicity distribution in the proton.On the basis of the interpretation of the longitudinal deep inelastic lepton-nucleon scattering data as a negative strange quark polarization in the proton and the preliminary results on the measurement of the longitudinal $\Lambda$ polarization at the $Z$ resonance in electron-positron annihilation,we predict a minus sign for the suggested observable. The experimental condition required for our suggestion is met by the HERA facilities, so the asymmetry considered can be measured by the HERMES experiments at HERA in the near future.Comment: 10 pages, Revtex, completely rephrased, references adde

The spatial and velocity distributions of hypervelocity stars

Hypervelocity stars (HVSs) found in the Galactic halo are probably the dynamical products of interactions between (binary) stars and the massive black hole(s) (MBH) in the Galactic center (GC). It has been shown that the detected HVSs are spatially consistent with being located on two thin disks (Lu et al.), one of which has the same orientation as the clockwise-rotating stellar disk in the GC. Here we perform a large number of three-body experiments of the interactions between the MBH and binary stars bound to it, and find that the probability of ejecting HVSs is substantially enhanced by multiple encounters between the MBH and binary stars at distances substantially larger than the initial tidal breakup radii. Assuming that the HVS progenitors are originated from the two disks, the inclination distribution of the HVSs relative to the disk planes can be reproduced by either the mechanism of tidal breakup of binary stars or the mechanism of ejecting HVSs by a hypothetical binary black hole (BBH) in the GC. However, an isotropical origination of HVS progenitors is inconsistent with the observed inclination distribution. Assuming that the HVSs were ejected out by the tidal breakup mechanism, its velocity distribution can be reproduced if their progenitors diffuse onto low angular momentum orbits slowly and most of the progenitors were broken up at relatively large distances due to multiple encounters. Assuming that the HVSs were ejected out by a BBH within the allowed parameter space in the GC, our simulations produce relatively flatter velocity spectra compared to the observed ones; however, the BBH mechanism cannot be statistically ruled out, yet. Future surveys of HVSs and better statistics of their spatial and velocity distributions should enable to distinguish the ejection mechanisms of HVSs and shed new light on the dynamical environment of the MBH.(abridged)Comment: 19 pages, 16 figure

MAP4K family kinases act in parallel to MST1/2 to activate LATS1/2 in the Hippo pathway.

The Hippo pathway plays a central role in tissue homoeostasis, and its dysregulation contributes to tumorigenesis. Core components of the Hippo pathway include a kinase cascade of MST1/2 and LATS1/2 and the transcription co-activators YAP/TAZ. In response to stimulation, LATS1/2 phosphorylate and inhibit YAP/TAZ, the main effectors of the Hippo pathway. Accumulating evidence suggests that MST1/2 are not required for the regulation of YAP/TAZ. Here we show that deletion of LATS1/2 but not MST1/2 abolishes YAP/TAZ phosphorylation. We have identified MAP4K family members--Drosophila Happyhour homologues MAP4K1/2/3 and Misshapen homologues MAP4K4/6/7-as direct LATS1/2-activating kinases. Combined deletion of MAP4Ks and MST1/2, but neither alone, suppresses phosphorylation of LATS1/2 and YAP/TAZ in response to a wide range of signals. Our results demonstrate that MAP4Ks act in parallel to and are partially redundant with MST1/2 in the regulation of LATS1/2 and YAP/TAZ, and establish MAP4Ks as components of the expanded Hippo pathway

Self-Diffusion in 2D Dusty Plasma Liquids: Numerical Simulation Results

We perform Brownian dynamics simulations for studying the self-diffusion in two-dimensional (2D) dusty plasma liquids, in terms of both mean-square displacement and velocity autocorrelation function (VAF). Super-diffusion of charged dust particles has been observed to be most significant at infinitely small damping rate $\gamma$ for intermediate coupling strength, where the long-time asymptotic behavior of VAF is found to be the product of $t^{-1}$ and $\exp{(-\gamma t)}$. The former represents the prediction of early theories in 2D simple liquids and the latter the VAF of a free Brownian particle. This leads to a smooth transition from super-diffusion to normal diffusion, and then to sub-diffusion with an increase of the damping rate. These results well explain the seemingly contradictory scattered in recent classical molecular dynamics simulations and experiments of dusty plasmas.Comment: 10 pages 5 figures, accepted by PR

The continuous p-centre problem: An investigation into variable neighbourhood search with memory

A VNS-based heuristic using both a facility as well as a customer type neighbourhood structure is proposed to solve the p-centre problem in the continuous space. Simple but effective enhancements to the original Elzinga-Hearn algorithm as well as a powerful ‘locate-allocate’ local search used within VNS are proposed. In addition, efficient implementations in both neighbourhood structures are presented. A learning scheme is also embedded into the search to produce a new variant of VNS that uses memory. The effect of incorporating strong intensification within the local search via a VND type structure is also explored with interesting results. Empirical results, based on several existing data set (TSP-Lib) with various values of p, show that the proposed VNS implementations outperform both a multi-start heuristic and the discrete-based optimal approach that use the same local search

Local Entropy Characterization of Correlated Random Microstructures

A rigorous connection is established between the local porosity entropy introduced by Boger et al. (Physica A 187, 55 (1992)) and the configurational entropy of Andraud et al. (Physica A 207, 208 (1994)). These entropies were introduced as morphological descriptors derived from local volume fluctuations in arbitrary correlated microstructures occuring in porous media, composites or other heterogeneous systems. It is found that the entropy lengths at which the entropies assume an extremum become identical for high enough resolution of the underlying configurations. Several examples of porous and heterogeneous media are given which demonstrate the usefulness and importance of this morphological local entropy concept.Comment: 15 pages. please contact [email protected] and have a look at http://www.ica1.uni-stuttgart.de/ . To appear in Physica