Bactericidal effect of corona discharges in atmospheric air

The present paper explores the possibilities of using impulsive and steady-state corona discharges for bio-decontamination operations. A high tension tubular corona electrode was stressed with positive or negative dc voltage with magnitude up to 26 kV, and a grounded mesh was used as an opposite electrode. Different operational regimes of this corona generator were investigated for the production of ozone in air flow and the inactivation of microorganisms. The test microorganisms used in this work were Escherichia coli and Staphylococcus aureus, populations of which were seeded onto agar plates. These bacterial plates were located behind the grounded mesh electrode to assess bactericidal efficacy. The results show that corona discharges have a strong bactericidal effect, for example positive flashing corona discharges were able to reduce populations of the test microorganism by 94% within a 30-60 sec time interval. Negative steady-state corona discharges also produce noticeable bactericidal effect, reducing population of E. coli and S. aureus by more than 97% within 120 sec energisation interval. The bactericidal efficiency of different corona discharge modes and its correlation with ozone levels produced by these discharges is discussed. The results obtained in this work will help in the design and development of compact plasma systems for environmental application

Successful elimination of factor VIII inhibitor using cyclosporin A

No abstract available

Space Launch System Base Heating Test: Experimental Operations & Results

NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Test methodology and conditions are presented, and base heating results from 76 runs are reported in non-dimensional form. Regions of high heating are identified and comparisons of various configuration and conditions are highlighted. Base pressure and radiometer results are also reported

III-V semiconductor waveguides for photonic functionality at 780 nm

Photonic integrated circuits based on III-V semiconductor polarization-maintaining waveguides were designed and fabricated for the first time for application in a compact cold-atom gravimeter1,2 at an operational wavelength of 780 nm. Compared with optical fiber-based components, semiconductor waveguides achieve very compact guiding of optical signals for both passive functions, such as splitting and recombining, and for active functions, such as switching or modulation. Quantum sensors, which have enhanced sensitivity to a physical parameter as a result of their quantum nature, can be made from quantum gases of ultra-cold atoms. A cloud of ultra-cold atoms may start to exhibit quantum-mechanical properties when it is trapped and cooled using laser cooling in a magneto-optical trap, to reach milli-Kelvin temperatures. The work presented here focuses on the design and fabrication of optical devices for a quantum sensor to measure the acceleration of gravity precisely and accurately. In this case the cloud of ultra-cold atoms consists of rubidium (87Rb) atoms and the sensor exploits the hyperfine structure of the D1 transition, from an outer electronic state of 5 2S ½ to 5 2P3/2 which has an energy of 1.589 eV or 780.241 nm. The short wavelength of operation of the devices dictated stringent requirements on the Molecular Beam Epitaxy (MBE) and device fabrication in terms of anisotropy and smoothness of plasma etch processes, cross-wafer uniformities and alignment tolerances. Initial measurements of the optical loss of the polarization-maintaining waveguide, assuming Fresnel reflection losses only at the facets, suggested a loss of 8 dB cm-1, a loss coefficient, α, of 1.9 (±0.3) cm-1

Pulsed ultraviolet light decontamination of artificially-generated microbiological aerosols

Airborne transmission of infectious organisms is a major public health concern, particularly within healthcare and communal public environments. Methods of environmental decontamination utilising pulsed ultraviolet (UV) light are currently available, however it is important that germicidal efficacy against airborne contamination is established. This study demonstrates evidence of the dose-response kinetics of airborne bacterial contamination when exposed to pulsed UV-rich (PUV) light. Bacterial aerosols (Staphylococcus epidermidis) were generated using a 6-Jet Collison nebuliser, and introduced into a custom-designed aerosol chamber which enabled prolonged airborne suspension and circulation. Bacterial aerosols were exposed to short duration pulses (~20 µs) of UV-rich light emitted from a xenon-filled flashlamp. The lamp was operated using a 1 kV solid–state pulsed power source, with a pulse frequency of 1 Hz, and output energy of 20 J/pulse. Post-treatment, air samples were extracted from the chamber using a BioSampler liquid impinger, and the surviving fraction was enumerated using standard microbiological culture methods. Results demonstrate successful aerosol inactivation, with a 66.4% reduction achieved with only 10 pulses of UV-rich light (P=<0.0002). Inactivation using continuous UV light was also investigated in order to quantify the comparative efficacy of these antimicrobial light regions. In addition to determining the inactivation kinetics, the spectral outputs of the pulsed and continuous UV sources were captured and compared in order to assess their comparative UV-C content, and subsequently assess how this UV content relates to their germicidal efficiency. Overall, results provide evidence of the dose-response kinetics of bacterial aerosols to PUV-rich light. As with continuous UV light, safety restrictions limit its application to unoccupied environments, or within sealed enclosures such as air handling units, however the reduced treatment times with PUV provides operational advantages over continuous light treatment

Development of an antimicrobial blended white LED system containing pulsed 405-nm LEDs for decontamination applications

This study details the design, build and testing of a prototype antimicrobial blended white light unit containing pulsed red, yellow, green and 405nm LEDs. With a push for alternative methods of disinfection, optical methods have become a topic of interest. Ultra-violet (UV) light is widely known for its antimicrobial properties however; 405nm light has demonstrated significant antimicrobial properties against many common hospital acquired pathogens. In this study, a pulsed, blended, white-light prototype with a high content of 405 nm antimicrobial light, was designed, built and tested. Antimicrobial efficacy testing of the prototype was conducted using Staphylococcus aureus and Pseudomonas. aeruginosa, two bacteria which are common causes of hospital acquired infections. These were exposure to 3 different light outputs from the prototype and the surviving bacteria enumerated. Results showed that the mixed light output provided a much better CRI and light output under which to work. Also, the light output containing 405 nm light provided an antimicrobial effect, with decontamination of 103 CFUml-1 populations of both bacterial species. The other light content (red, yellow, green) had no beneficial or adverse effects on the antimicrobial properties of the 405nm light. The results suggest that with further development, it could be possible to produce an antimicrobial blended white light containing pulsed 405nm light that could supplement or even replace standard white lighting in certain environments

Biodiversity 2020: climate change evaluation report

In 2011, the government published Biodiversity 2020: A strategy for England’s wildlife and ecosystem services [1]. This strategy for England builds on the 2011 Natural Environment White Paper - NEWP [2] and provides a comprehensive picture of how we are implementing our international and EU commitments. It sets out the strategic direction for biodiversity policy between 2011-2020 on land (including rivers and lakes) and at sea, and forms part of the UK’s commitments under the ‘the Aichi targets’ agreed in 2010 under the United Nations Convention of Biological Diversity’s Strategic Plan for Biodiversity 2011-2020 [3]. Defra is committed to evaluating the Biodiversity 2020 strategy and has a public commitment to assess climate change adaptation measures. This document sets out the information on assessing how action under Biodiversity 2020 has helped our wildlife and ecosystems to adapt to climate change. Biodiversity 2020 aims to halt the loss of biodiversity and restore functioning ecosystems for wildlife and for people. The outcomes and actions in Biodiversity 2020, although wider in scope, aimed to increase resilience of our wildlife and ecosystems in the face of a changing climate. In order to inform the assessment, we have defined which of the measurable outputs under Biodiversity 2020 contribute to resilience. Biodiversity 2020 included plans to develop and publish a dedicated set of indicators to assess progress towards the delivery of the strategy. The latest list (at the time of writing), published in 2017, contains 24 biodiversity indicators [4] that would help inform progress towards achieving specific outcomes, they are also highly relevant to the outputs (detailed below) that form the basis for this evaluation. The Adaptation Sub-Committee’s 2017 UK Climate Change Risk Assessment Evidence Report [5] sets out the priority climate change risks and opportunities for the UK. The ASC also produced a review of progress in the National Adaptation Programme - “Progress in preparing for climate change” [6], which highlights adaptation priorities and progress being made towards achieving them. The UK Government’s response to the ASC [7] review includes a set of recommendations, of which Recommendation 6 states that “Action should be taken to enhance the condition of priority habitats and the abundance and range of priority species”. The recommendation further iterated that “This action should maintain or extend the level of ambition that was included in Biodiversity 2020” and that “An evaluation should be undertaken of Biodiversity 2020 including the extent to which goals have been met and of the implications for resilience to climate change.” To this, end an evaluation process has been put in place to define: a. What worked and why? Which actions or activities have had the greatest benefit in terms of delivering the desired outcomes? And, conversely, what prevented progress? b. Where are the opportunities? What are the financial, political, scientific and social opportunities for furthering the desired outcomes in the future? These objectives underpin the evaluation process for actions to date, and will also inform future actions and the iteration of a new nature strategy for England

Protein engineering expands the effector recognition profile of a rice NLR immune receptor

Plant nucleotide binding, leucine-rich repeat (NLR) receptors detect pathogen effectors and initiate an immune response. Since their discovery, NLRs have been the focus of protein engineering to improve disease resistance. However, this approach has proven challenging, in part due to their narrow response specificity. Previously, we revealed the structural basis of pathogen recognition by the integrated heavy metal associated (HMA) domain of the rice NLR Pikp (Maqbool et al., 2015). Here, we used structure-guided engineering to expand the response profile of Pikp to variants of the rice blast pathogen effector AVR-Pik. A mutation located within an effector-binding interface of the integrated Pikp-HMA domain increased the binding affinity for AVR-Pik variants in vitro and in vivo. This translates to an expanded cell-death response to AVR-Pik variants previously unrecognized by Pikp in planta. The structures of the engineered Pikp-HMA in complex with AVR-Pik variants revealed the mechanism of expanded recognition. These results provide a proof-of-concept that protein engineering can improve the utility of plant NLR receptors where direct interaction between effectors and NLRs is established, particularly where this interaction occurs via integrated domains

Toward a Common Understanding of CBE Implementation

New Hampshire public high schools are required to implement competency-based education (CBE) models; however, no comprehensive research describes the CBE models implemented across the state. Knowledge of implementation is a necessary precursor to determining the impact of CBE on student outcomes. The purpose of this quantitative study was to describe the extent New Hampshire’s public educational leaders have integrated the five essential CBE characteristics in the CBE models implemented at their high schools. Data were collected via a quantitative instrument distributed to New Hampshire public high school and district administrators. Data were analyzed using descriptive and inferential algorithms. Results indicated that a majority of participants agreed that their CBE model included explicitly stated and measured outcomes, varied and authentic assessments, timely interventions, and a focus on learner mindsets. New Hampshire public high school CBE models have yet to fully implement flexible student advancement. Teacher values and beliefs was the most significant local force impacting the implementation of each of the five CBE characteristics