Clinical studies of the high-intensity narrow-spectrum light environmental decontamination system (HINS-light EDS), for continuous disinfection in the burn unit inpatient and outpatient settings

Infections are the leading cause of morbidity and mortality in burn patients and prevention of contamination from exogenous sources including the hospital environment is becoming increasingly emphasised. The High-Intensity Narrow-Spectrum light Environmental Decontamination System (HINS-light EDS) is bactericidal yet safe for humans, allowing continuous disinfection of the environment surrounding burn patients. Environmental samples were collected from inpatient isolation rooms and the outpatient clinic in the burn unit, and comparisons were then made between the bacterial contamination levels observed with and without use of the HINS-light EDS. Over 1000 samples were taken. Inpatient studies, with sampling carried out at 0800 h, demonstrated a significant reduction in the average number of bacterial colonies following HINS-light EDS use of between 27% and 75%, (p<0.05). There was more variation when samples were taken at times of increased activity in the room. Outpatient studies during clinics demonstrated a 61% efficacy in the reduction of bacterial contamination on surfaces throughout the room during the course of a clinic (p=0.02). The results demonstrate that use of the HINS-light EDS allows efficacious bacterial reductions over and above that achieved by standard cleaning and infection control measures in both inpatient and outpatient settings in the burn unit

RNA mutagenesis yields highly diverse mRNA libraries for in vitro protein evolution

BACKGROUND: In protein drug development, in vitro molecular optimization or protein maturation can be used to modify protein properties. One basic approach to protein maturation is the introduction of random DNA mutations into the target gene sequence to produce a library of variants that can be screened for the preferred protein properties. Unfortunately, the capability of this approach has been restricted by deficiencies in the methods currently available for random DNA mutagenesis and library generation. Current DNA based methodologies generally suffer from nucleotide substitution bias that preferentially mutate particular base pairs or show significant bias with respect to transitions or transversions. In this report, we describe a novel RNA-based random mutagenesis strategy that utilizes Qβ replicase to manufacture complex mRNA libraries with a mutational spectrum that is close to the ideal. RESULTS: We show that Qβ replicase generates all possible base substitutions with an equivalent preference for mutating A/T or G/C bases and with no significant bias for transitions over transversions. To demonstrate the high diversity that can be sampled from a Qβ replicase-generated mRNA library, the approach was used to evolve the binding affinity of a single domain V(NAR )shark antibody fragment (12Y-2) against malarial apical membrane antigen-1 (AMA-1) via ribosome display. The binding constant (K(D)) of 12Y-2 was increased by 22-fold following two consecutive but discrete rounds of mutagenesis and selection. The mutagenesis method was also used to alter the substrate specificity of β-lactamase which does not significantly hydrolyse the antibiotic cefotaxime. Two cycles of RNA mutagenesis and selection on increasing concentrations of cefotaxime resulted in mutants with a minimum 10,000-fold increase in resistance, an outcome achieved faster and with fewer overall mutations than in comparable studies using other mutagenesis strategies. CONCLUSION: The RNA based approach outlined here is rapid and simple to perform and generates large, highly diverse populations of proteins, each differing by only one or two amino acids from the parent protein. The practical implications of our results are that suitable improved protein candidates can be recovered from in vitro protein evolution approaches using significantly fewer rounds of mutagenesis and selection, and with little or no collateral damage to the protein or its mRNA

Dye Sensitization of Nanocrystalline Titanium Dioxide with Osmium and Ruthenium Polypyridyl Complexes

A series of osmium polypyridyl complexes having various ground-state reduction potentials has been synthesized and used to sensitize nanoporous titanium dioxide electrodes to solar illumination. The spectral response and current vs potential properties of electrodes modified with these dyes have been compared with the behavior of their ruthenium analogues. The trends can be explained by the differences in absorption spectra and ground-state redox potentials. The osmium complexes appear to be promising candidates for further optimization in operating photoelectrochemical cells for solar energy conversion applications. Of the materials studied, all complexes having ground-state redox potentials in methanol more positive than ∼0.4 V vs aqueous SCE were able to sustain oxidation of I-/I_3- with a high steady-state quantum yield. For electrodes with very low dye coverages, the open-circuit voltage was mainly determined by the rate of reduction of I_2, whereas for high dye coverages, the open-circuit voltage depended on the nature of the complex and on the dye loading level

Inverse plan optimization accounting for random geometric uncertainties with a multiple instance geometry approximation (MIGA)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135142/1/mp1016.pd

Current Density versus Potential Characteristics of Dye-Sensitized Nanostructured Semiconductor Photoelectrodes. 2. Simulations

The impact of changes in various parameters on the steady-state current density−potential (J−E) characteristics of dye-sensitized nanostructured semiconductor photoelectrodes has been evaluated through a series of simulations. The model parameters can be divided into three classes, designated as type I, type II, and type III, respectively. Type I parameters primarily affect the open-circuit potential without changing the overall shape of the J−E curves. Type II parameters primarily affect the limiting quantum yield for photocurrent production. Rate constants for injection and quenching of the excited state of the dye by the contacting phase are type II parameters, whereas the rate constant for the direct electrolyte reduction reaction, the reduced equilibrium constant for iodine formation, and the rate constant for recombination are type I parameters. The rate constant for regeneration affects both the shape of the J−E curves and the limiting quantum yield for photocurrent flow, and it is therefore designated as a type III parameter. Variation of the diffusion coefficient parameter for electrons in the semiconducting membrane produces a mixed response having both type I and II characteristics. Comparisons between simulations and experimental data have delineated the factors that should be manipulated to increase the energy conversion efficiency of photoelectrochemical cells that utilize nanostructured TiO_2 electrodes