Growth rate effects in soft CoFe films

We report on growth rate effects in sputter-deposited CoFe films prepared using high target utilization sputtering technology (HiTUS). We find that the grain structure of these polycrystalline films is closely related to the growth rate. By changing the growth rate, samples were prepared with different grain structure, which in turn had the effect of changing the magnetic properties of the films. We demonstrate control of the coercivity, which varied by a factor of more than ten. This was achieved via grain size control in CoFe films of thickness 20 nm. Furthermore, by employing a two-step sputtering process, in which two extreme growth rates are used sequentially, we were able to tune the saturation magnetization

Novel sputtering-technology for grain-size control

In this paper, we present a description of a novel high-rate plasma sputtering system that allows the control of grain size in sputtered films. Additionally, the system has the advantage of a better utilization of the target material (around 80% to 90%) by eliminating the race track at the target as in conventional plasma magnetron sputtering systems. The potential and capabilities of this novel plasma sputtering device are demonstrated in this paper by the deposition of a number of different Cr thin films suitable for underlayers in thin-film media and for which we have performed a systematic X-ray and TEM analysis to determine the grain-size histograms, mean grain diameters, and their relationship to the sputtering processes

Effect of blade geometry on the aerodynamic loads produced by vertical-axis wind turbines

Accurate aerodynamic modelling of vertical-axis wind turbines poses a significant challenge. The rotation of the turbine induces large variations in the angle of attack of its blades that can manifest as dynamic stall. In addition, interactions between the blades of the turbine and the wake that they produce can result in impulsive changes to the aerodynamic loading. The Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics of three different vertical-axis wind turbine configurations. It is known that vertical-axis turbines with either straight or curved blades deliver torque to their shaft that fluctuates at the blade passage frequency of the rotor. In contrast, a turbine with helically twisted blades delivers a relatively steady torque to the shaft. In this article, the interactions between helically twisted blades and the vortices within their wake are shown to result in localized perturbations to the aerodynamic loading on the rotor that can disrupt the otherwise relatively smooth power output that is predicted by simplistic aerodynamic tools that do not model the wake to sufficient fidelity. Furthermore, vertical-axis wind turbines with curved blades are shown to be somewhat more susceptible to local dynamic stall than turbines with straight blades

Transparent and Flexible Thin Film Electroluminescent Devices Using HiTUS Deposition and Laser Processing Fabrication

Highly transparent thin film electroluminescent structures offering excellent switch on characteristics, high luminance and large break-down voltages have been deposited onto glass and flexible polymeric materials with no substrate heating using high target utilization sputtering. Deposition of ZnS:Mn as the active light emitting layer and Y2O3,Al2O3,Ta2O5, and HfO2 as dielectric materials arranged in single and multiple layer configurations were investigated. Devices incorporating Al2O3,HfO2 quadruple layers demonstrate the highest attainable luminance at low threshold voltage. Single pulse excimer laser irradiation of the phosphor layer prior to deposition of the top dielectric layer enhanced the luminance of the devices. The devices fabricated on glass and polymeric substrates exhibited a maximum luminance of 500 and 450 cdm−2 when driven at 270 VRMS and 220 VRMS, respectively, with a 1.0 kHz sine wave

Screening fungi isolated from historic Discovery Hut on Ross Island, Antarctica for cellulose degradation

To survive in Antarctica, early explorers of Antarctica's Heroic Age erected wooden buildings and brought in large quantities of supplies. The introduction of wood and other organic materials may have provided new nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials. From 30 samples taken from Discovery Hut, 156 filamentous fungi were isolated on selective media. Of these, 108 were screened for hydrolytic activity on carboxymethyl cellulose, of which 29 demonstrated activities. Endo-1, 4-β-glucanase activity was confirmed in the extracellular supernatant from seven isolates when grown at 4°C, and also when they were grown at 15°C. Cladosporium oxysporum and Geomyces sp. were shown to grow on a variety of synthetic cellulose substrates and to use cellulose as a nutrient source at temperate and cold temperatures. The research findings from the present study demonstrate that Antarctic filamentous fungi isolated from a variety of substrates (wood, straw, and food stuffs) are capable of cellulose degradation and can grow well at low temperatures

Evaluation of the MODS Culture Technique for the Diagnosis of Tuberculous Meningitis

Tuberculous meningitis (TBM) is a devastating condition. The rapid instigation of appropraite chemotherapy is vital to reduce morbidity and mortality. However rapid diagnosis remains elusive; smear microscopy has extremely low sensitivity on cerebrospinal fluid (CSF) in most laboratories and PCR requires expertise with advanced infrastructure and has sensitivity of only around 60% under optimal conditions. Neither technique allows for the microbiological isolation of M. tuberculosis and subsequent drug susceptibility testing. We evaluated the recently developed microscopic observation drug susceptibility (MODS) assay format for speed and accuracy in diagnosing TBM.Two hundred and thirty consecutive CSF samples collected from 156 patients clinically suspected of TBM on presentation at a tertiary referal hospital in Vietnam were enrolled into the study over a five month period and tested by Ziehl-Neelsen (ZN) smear, MODS, Mycobacterial growth Indicator tube (MGIT) and Lowenstein-Jensen (LJ) culture. Sixty-one samples were from patients already on TB therapy for >1day and 19 samples were excluded due to untraceable patient records. One hundred and fifty samples from 137 newly presenting patients remained. Forty-two percent (n = 57/137) of patients were deemed to have TBM by clinical diagnostic and microbiological criteria (excluding MODS). Sensitivity by patient against clinical gold standard for ZN smear, MODS MGIT and LJ were 52.6%, 64.9%, 70.2% and 70.2%, respectively. Specificity of all microbiological techniques was 100%. Positive and negative predictive values for MODS were 100% and 78.7%, respectively for HIV infected patients and 100% and 82.1% for HIV negative patients. The median time to positive was 6 days (interquartile range 5-7), significantly faster than MGIT at 15.5 days (interquartile range 12-24), and LJ at 24 days (interquartile range 18-35 days) (P<0.01).We have shown MODS to be a sensitive, rapid technique for the diagnosis of TBM with high sensitivity, ease of performance and low cost (0.53 USD/sample)

Black and White: investigations on the ecology, biology and biological control of sapstain fungi in New Zealand

This study examined ecology, colonisation, biological control and detection of sapstain fungi in New Zealand. A nationwide survey of New Zealand sapstain fungi was undertaken between 1996 and1998. In total, 1035 sites were sampled in the North and South Islands. From these collections, 1755 potential sapstain fungi were isolated and seventeen individual species were identified. The predominant sapstain fungi identified were Sphaeropsis sapinea, Ophiostoma ips, O. floccosum, O. piliferum, O. querci and Leptographium procerum. This data was subsequently evaluated according to ecological criteria, including geographical and temporal distribution of sapstain fungi. A greater diversity of sapstain fungi was found in areas of New Zealand that were primarily plantation forestry. S. sapinea was isolated during more generalised forest sampling, and from both native and plantation forests. Ophiostoma species were isolated more frequently from Pinus radiata plantations, processing plants including mills and ports and were mainly isolated from harvested forest material such as logs, wood chips, and other wood products. S. sapinea was isolated more frequently in spring and summer while Ophiostoma species predominated during autumn and winter periods, probably linked with insect vectoring. This was the first attempt to link the sapstain organisms identified in New Zealand with their overall distribution within sectors of the forest industry, in different wood species, and in different types of wood samples. New Zealand is one of the world's largest exporters of softwood logs. Exports of forest products provide 4% of New Zealand’s gross domestic product (GDP) with Japan, Korea, United States and the Philippines as major export markets for P. radiata logs. Conditions found within the holds of ships were thought likely to be ideal for the rapid colonisation of the sapstain fungi that results in dark penetrating stains. Log export research was designed to determine the extent of sapstain colonisation at specific points in the processing of logs from harvesting to the export destination. Two trials were established, in New Zealand summer and in winter, where mature P. radiata logs were harvested in New Zealand and shipped to export ports in Japan. Microclimatic conditions (temperature and relative humidity) on board the ships were recorded using data loggers both above deck and below deck. Nine species of sapstain fungi were isolated from logs during the summer trial. The most common species isolated were O. floccosum, O. querci and O. setosum. In contrast, a different combination of nine species was detected during the winter trial. S. sapinea, O. querci, O. floccosum, O. setosum and Ophiostoma piceae were most commonly isolated. The results of this study showed that the New Zealand sapstain fungi were being exported on logs. However, many of these fungi were previously recorded in Japan. In addition, no serious pathogens were detected. It was recognised during the sapstain fungal survey and export trials that a more thorough fundamental understanding of sapstain colonisation was required to properly determine the impacts of sapstain fungi to the New Zealand forest industry. In vitro and field studies were established to measure the relative colonisation of different species of sapstain fungi using synthetic media and P. radiata wood. These studies were undertaken to determine which sapstain species colonised, and how species interacted with each other following inoculation. In addition, the impacts of environmental conditions on the establishment and development of fungi and the resulting associated stains were determined. Temperature was found to affect the growth of various species of sapstain fungi on synthetic media and on P. radiata wood and logs. In the field studies O. floccosum was found to be the most successful coloniser of P. radiata logs in both winter and summer. Environmental factors such as temperature and moisture content were found to affect stain development. All fungal treatments developed sapstain discolouration from 15 days following inoculation in the summer field trial. In contrast, no stain was evident on any treatment in the winter field trial 60 days following inoculation. The colonisation of P. radiata by sapstain fungi was determined using microscopic techniques. Sapstain fungal hyphae were abundantly present in the ray parenchyma cells, tracheid lumen and resin canals of P. radiata wood. No differences in hyphal penetration were observed between the different sapstain fungal species at the cellular level. From these results a better understanding of the biology of sapstain species emerged. This new knowledge of the mechanisms and environmental triggers of fungal colonisation and stain development will aid in the more advanced technologies and management strategies to successfully control sapstain. The many negative environmental impacts associated with traditional anti-sapstain chemical treatments led to increased interest in the more benign treatments of logs and wood using biological control technologies. The potential biological treatment of sapstain fungi using albino strains of O. floccosum, O. piceae and O. pluriannulatum was evaluated. These albino fungi demonstrated varied growth characteristics at different temperatures on both synthetic media and on P. radiata wood specimens. Comparable growth was found when evaluating wild type and albino sapstain strains in synthetic media and P. radiata wood in laboratory and field studies. Four field trials showed considerable variation in the biological control potential of the albino strains against wild type sapstain fungi. The mode of action of the albino strains was found to be competitive, through the use of primary resource capture of wood nutrients. However, albino O. floccosum strains were shown to produce zonal barriers when challenged with S. sapinea. Proteomic analysis of cell wall proteins was undertaken to differentiate sapstain fungi from other wood inhabiting fungi and in an attempt to develop a method of determining the presence of sapstain fungi in wood prior to the development of stain. Proteins were extracted from the cell walls of various sapstain fungi (L. procerum, O. ips, O. Querci and S. sapinea) and wood inhabiting fungi (Alternaria alternata, Epicoccum nigrum, Trichoderma koningi) grown in liquid culture. Two dimensional (2D) protein profiles were made and compared. A total of 93 proteins were analysed using mass spectroscopy and the profiles compared to protein databases. This is the first investigation using proteomics of the cell wall proteins of Ophiostoma species and S. sapinea. This study addressed the importance of sapstain fungi in New Zealand on P. radiata and increased our understanding of ecological requirements of the different sapstain species. Differences between these species with respect to colonisation and the development of associated stains were identified and investigated, enabling a critical evaluation of those species that were found to be most significant to the New Zealand forest industry. The future of sapstain management depends on a thorough ecological understanding of key sapstain fungal species involved in the cosmetic degradation of wood and an ability to manage the impacts of these species on the New Zealand forest industry using a combination of forest management practises and biological and chemical control techniques

The management of tetanus in adults in an intensive care unit in Southern Vietnam

Background: Tetanus remains common in many low- and middle-income countries (LMICs) yet the evidence base guiding management of this disease is extremely limited, particularly with respect to contemporary management options. Sharing knowledge about practice may facilitate improvement in outcomes elsewhere. Methods: We describe clinical interventions and outcomes of 180 adult patients ≥16 years-old with tetanus enrolled in prospective observational studies at a specialist infectious diseases hospital in Southern Vietnam. Patients were treated according to a holistic management protocol encompassing wound-care, antitoxin, antibiotics, symptom control, airway management, nutrition and de-escalation criteria. Results: Mortality rate in our cohort was 2.8%, with 90 (50%) patients requiring mechanical ventilation for a median 16 [IQR 12-24] days. Median [IQR] duration of ICU stay was 15 [8-23] days. Autonomic nervous system dysfunction occurred in 45 (25%) patients. Hospital acquired infections occurred in 77 (43%) of patients. Conclusion: We report favourable outcomes for patients with tetanus in a single centre LMIC ICU, treated according to a holistic protocol. Nevertheless, many patients required prolonged intensive care support and hospital acquired infections were common