Zoster neuritis of lumbar nerves: A clinical, magnetic resonance imaging, and electrodiagnostic evaluation.

Human herpesviruses, particularly the varicella-zoster virus, are notorious for affecting the central nervous system, especially when secondarily reactivated from a latent state. We present one such case of zoster radiculitis with an ensemble of typical dermatological and neurological features diagnosed on imaging and cerebrospinal fluid (CSF) studies and encourage the consideration of viral (zoster) neuritis as a differential in patients presenting with radicular pain.

On the rupture of DNA molecule.

Using Langevin dynamics simulations, we study effects of the shear force on the rupture of a double stranded DNA molecule. The model studied here contains two single diblock copolymers interacting with each other. The elastic constants of individual segments of diblock copolymer are considered to be different. We showed that the magnitude of the rupture force depends on whether the force is applied at 3' - 3' - ends or 5' - 5' - ends. Distributions of extension in hydrogen bonds and covalent bonds along the chain show the striking differences. Motivated by recent experiments, we have also calculated the variation of rupture force for different chain lengths. Results obtained from simulations have been validated with the analytical calculation based on the ladder model of DNA.

Dissecting Allosteric Mutations for Antibiotic Resistance by Time-Dependent Linear Response Theory.

We report a new approach that combines molecular dynamics trajectories with time-dependent linear response theory to compute the time evolution of residue fluctuation responses to force perturbations exerted at functional sites. Applying this new approach to TEM-1 beta-lactamase, we observe that the time-resolved response profiles of allosteric sites to perturbations of TEM-1 active sites are distinct from those of non-allosteric residues. Using Fourier transformations, we convert the time domain response profiles to the frequency domain and demonstrate that the frequency space representation of the perturbation response can capture the mutational behavior of each site when applied to deep sequencing mutational data. Furthermore, we show that classification models built on perturbation responses can accurately identify distal positions that regulate antibiotic resistance. These findings provide insights into the contributions of specific residues to resistance-encoded in time-resolved perturbation response behavior and highlight the importance of this new approach in identifying allosteric mutations, opening avenues for the potential characterization of additional allosteric positions without extensive computational simulations.

Statistical mechanics of DNA rupture: theory and simulations.

We study the effects of the shear force on the rupture mechanism on a double stranded DNA. Motivated by recent experiments, we perform the atomistic simulations with explicit solvent to obtain the distributions of extension in hydrogen and covalent bonds below the rupture force. We obtain a significant difference between the atomistic simulations and the existing results in the literature based on the coarse-grained models (theory and simulations). We discuss the possible reasons and improve the coarse-grained model by incorporating the consequences of semi-microscopic details of the nucleotides in its description. The distributions obtained by the modified model (simulations and theoretical) are qualitatively similar to the one obtained using atomistic simulations.

Application of rapid read-out cleaning indicators for improved process control in hospital sterile services departments.

BACKGROUND: Heightened awareness of the importance of cleaning has led to an emphasis on automated systems for the decontamination of re-usable medical devices. The authors have previously described an enzymatic indicator system, based on thermostable adenylate kinases (tAK), for quantitative monitoring of automated cleaning processes within hospital sterile services departments (SSDs). AIM: To evaluate tAK indicators for routine process monitoring across a range of SSDs with different cleaning chemistries and different automated washer disinfectors (AWDs). METHODS: tAK indicator devices and alternative industry test indicators were included in five independent cleaning cycles in each of eight different AWDs. Residual tAK post wash was determined by a coupled luciferase assay using a modified hygiene monitoring system. FINDINGS: In all cases, with the exception of a single test, the alternative indicators showed that cleaning had been adequate. They were not able to discriminate between the performance of different processes. In contrast, the tAK indicators were able to resolve differences in the performance of processes across the different SSDs. Where the tAK indicators identified cleaning to the limits of detection of the assay, this demonstrated a log10 enzyme removal factor of >5.69. CONCLUSION: The results suggest that tAK indicators are suitable for providing improved process control for automated cleaning processes, being able to distinguish between wash performance in different hospital settings and between individual process runs. This technology is believed to be a useful addition to routine AWD performance qualification when used as a daily or weekly test.