Burkholderia pseudomallei: an update on disease, virulence and host interaction

Burkholderia pseudomallei is the etiological agent of melioidosis, a life-threatening disease of humans and animals that occurs primarily in Southeast Asia and northern Australia. The distribution of B. pseudomallei and occurrence of melioidosis globally is very much evident. This soil and water-dwelling saprophyte is resilient to various environments. This organism has gained further notoriety following the Centre for Disease Control’s classification of B. pseudomalleias a Tier 1 biological agent. Despite several decades of clinical research, the mortality rate for melioidosis remains high. Genomics-based studies have demonstrated the plasticity of the B. pseudomallei genome and the coding sequences consists of a myriad of functions that enable the bacteria to adapt to these hostile environments as well as various hosts. Diagnosis is mainly based on bacterial culture or serological assays whilst treatment is limited to third generation cephalosporins. To date, no vaccine is currently available as an immunoprophylaxis for melioidosis. By utilising the available genome sequence, a number of virulence factors have recently been identified and have provided more insight into the pathogenesis of B. pseudomallei. These factors include surface associated proteins as well as secreted effector proteins and their corresponding secretion systems. In addition, a number of recent studies on host-pathogen interaction have also demonstrated how the pathogen is able to subvert the host immune system and survive within the cell. This review presents an overview of the current understanding on B. pseudomallei pathogenesis and the disease melioidosis

Differences in work environment for staff as an explanation for variation in central line bundle compliance in intensive care units.

BACKGROUND: Central line-associated bloodstream infections (CLABSIs) are a common and costly quality problem, and their prevention is a national priority. A decade ago, researchers identified an evidence-based bundle of practices that reduce CLABSIs. Compliance with this bundle remains low in many hospitals. PURPOSE: The aim of this study was to assess whether differences in core aspects of work environments-workload, quality of relationships, and prioritization of quality-are associated with variation in maximal CLABSI bundle compliance, that is, compliance 95%-100% of the time in intensive care units (ICUs). METHODOLOGY/APPROACH: A cross-sectional study of hospital medical-surgical ICUs in the United States was done. Data on work environment and bundle compliance were obtained from the Prevention of Nosocomial Infections and Cost-Effectiveness Refined Survey completed in 2011 by infection prevention directors, and data on ICU and hospital characteristics were obtained from the National Healthcare Safety Network. Factor and multilevel regression analyses were conducted. FINDINGS: Reasonable workload and prioritization of quality were positively associated with maximal CLABSI bundle compliance. High-quality relationships, although a significant predictor when evaluated apart from workload and prioritization of quality, had no significant effect after accounting for these two factors. PRACTICE IMPLICATIONS: Aspects of the staff work environment are associated with maximal CLABSI bundle compliance in ICUs. Our results suggest that hospitals can foster improvement in ensuring maximal CLABSI bundle compliance-a crucial precursor to reducing CLABSI infection rates-by establishing reasonable workloads and prioritizing quality

Effects of fabric counts and weave designs on the properties of laminated woven kenaf carbon fibre reinforced epoxy hybrid composites

The effects of different fabric materials namely weave designs (plain and satin) and fabric counts (5 × 5 and 6 × 6) on the properties of laminated woven kenaf/carbon fibre reinforced epoxy hybrid composites were evaluated. The hybrid composites were fabricated from two types of fabric, i.e., woven kenaf that was made from a yarn of 500tex and carbon fibre, by using vacuum infusion technique and epoxy resin as matrix. The panels were tested for tensile, flexural, and impact strengths. The results have revealed that plain fabric is more suitable than satin fabric for obtaining high tensile and impact strengths. Using a fabric count of 5 × 5 has generated composites that are significantly higher in flexural modulus as compared to 6 × 6 which may be attributed to their structure and design. The scanned electron micrographs of the fractured surfaces of the composites demonstrated that plain woven fabric composites had better adhesion properties than satin woven fabric composites, as indicated by the presence of notably lower amount of fibre pull out

Step structure and ordering in Te-doped GaInP

Journal ArticleThe step structure and CuPt ordering in GaInP layers grown by organometallic vapor phase epitaxy on singular GaAs substrates have been investigated as a function of Te (DETe) doping using atomic force microscopy, and electrical and optical properties measurements. The degree of order decreases for Te concentrations of 1018 cm3. It is estimated from the photoluminescence peak energy to be approximately 0.5 for undoped layers and the layers are completely disordered at sufficiently high Te doping levels. The bandgap energy is changed by 110 meV as the Te doping level increases from 1017 to 1018 cm3. The step structure also changes markedly over the range of doping that produces disordering, from a mixture of monolayer and bilayer steps for undoped layers to solely monolayer steps for electron concentrations exceeding 1018 cm_3. For growth at 670 °C, the spacing between 1 10 steps increased by over an order of magnitude as the doping level was changed over the range investigated, while the step spacing between 110 steps increased only slightly. In general, Te doping significantly improves the surface morphology viewed using atomic force microscopy. The degree of order and surface structure are changed at exactly the same doping concentration. This suggests that the disordering may be controlled by the fast propagation of 1 10 steps due to kinetic effects at the step edges. A qualitative model is presented to explain these effects

Step structure and ordering in GaInP

Journal ArticlePresents information from an experiment on the step structure and ordering in GalnP. Information on the step spacing and degree of order in the epitaxial layers; Details on the experiment; Results from the experiment

Step structure and ordering in Zn-doped GaInP

Journal ArticlePresents the results of a study of Zinc dopant effects on both step structure and ordering in GaInP in an effort to further clarify the disordering mechanism. Comparison of the results obtained for Zinc with those reported for tellurium; Experiment; Results; Discussion; Conclusion

Te doping of GaInP: ordering and step structure

Journal ArticleThe donor Te has been added to GaInP during organometallic vapor phase epitaxial growth using the precursor diethyltelluride. In agreement with previous studies, the addition of high Te concentrations leads to the elimination of the CuPt ordering observed in undoped layers. The degree of order is estimated from the low temperature photoluminescence peak energy to decrease from 0.5 at Te concentrations of 2 1017 cm 3 to 0 for Te concentrations of 6 1017 cm 3. This is verified by transmission electron diffraction studies, which show the elimination of the ½ 111 superlattice spots at high Te doping levels. A remarkable change in the surface structure is found to accompany this decrease in ordering: The surfaces become much smoother. Step bunching is observed to disappear for the vicinal GaAs substrates, misoriented from 001 by 3° in the B direction, and three-dimensional island or mound formation is eliminated for the singular 001 substrates. A qualitative model is presented explaining this behavior based on the effect of Te on the step structure and the bonding at step edges, both of which affect the adatom sticking at steps

Influence of tellurium doping on step bunching of GaAs (001) vicinal surfaces grown by organometallic vapor phase epitaxy

Journal ArticleAtomic force microscopy has been used to investigate the influence of controlled tellurium Te incorporation on the step structure of GaAs grown by organometallic vapor phase epitaxy on vicinal 001 surfaces. Te doping, using the precursor diethyltelluride, is found to markedly decrease the surface roughness. Step bunching, observed for undoped layers, is totally eliminated. Only monolayer steps are formed for Te concentrations of 4 1017 cm 3. A model is proposed to account for these effects and the results reported previously for GaInP

Quantum Monte Carlo Calculations of Pion Scattering from Li

We show that the neutron and proton transition densities predicted by recent quantum Monte Carlo calculations for A=6,7 nuclei are consistent with pion scattering from 6Li and 7Li at energies near the Delta resonance. This has provided a microscopic understanding of the enhancement factors for quadrople excitations, which were needed to describe pion inelastic scattering within the nuclear shell model of Cohen and Kurath.Comment: 10 pages, REVTeX, 3 postscript figures; added calculation of elastic and inelastic pion scattering from 6Li at multiple energie