The effects of metabolic work rate and ambient environment on physiological tolerance times while wearing explosive and chemical personal protective equipment

This study evaluated the physiological tolerance times when wearing explosive and chemical (>35kg) personal protective equipment (PPE) in simulated environmental extremes across a range of differing work intensities. Twelve healthy males undertook nine trials which involved walking on a treadmill at 2.5, 4 and 5.5 km.h-1 in the following environmental conditions, 21, 30 and 37 °C wet bulb globe temperature (WBGT). Participants exercised for 60 min or until volitional fatigue, core temperature reached 39 °C, or heart rate exceeded 90% of maximum. Tolerance time, core temperature, skin temperature, mean body temperature, heart rate and body mass loss were measured. Exercise time was reduced in the higher WBGT environments (WBGT37tolerance times are influenced by the external environment and workload, and that cardiovascular strain is the limiting factor to work tolerance when wearing this heavy multi layered PPE.

Ramipril - improving exercise tolerance in intermittent claudication?

Peripheral artery disease (PAD) is one of the most common manifestations of systemic atherosclerosis. It is estimated that 10-15% of the general population is affected by PAD, whereby the narrowed arteries lead to reduced blood flow to the extremeties - particularly the legs. While many people have mild or no systems with PAD, approximately one-third of people experience intermittent claudication (IC).

Inside the ‘Hurt Locker’: The combined effects of explosive ordnance disposal and chemical protective clothing on physiological tolerance time in extreme environments

Background Explosive ordnance disposal (EOD) technicians are often required to wear specialised clothing combinations that not only protect against the risk of explosion but also potential chemical contamination. This heavy (>35kg) and encapsulating ensemble is likely to increase physiological strain by increasing metabolic heat production and impairing heat dissipation. This study investigated the physiological tolerance times of two different chemical protective undergarments, commonly worn with EOD personal protective clothing, in a range of simulated environmental extremes and work intensities Methods Seven males performed eighteen trials wearing two ensembles. The trials involved walking on a treadmill at 2.5, 4 and 5.5 km.h-1 at each of the following environmental conditions, 21, 30 and 37°C wet bulb globe temperature (WBGT). The trials were ceased if the participants’ core temperature reached 39°C, if heart rate exceeded 90% of maximum, if walking time reached 60 minutes or due to volitional fatigue. Results Physiological tolerance times ranged from 8 to 60 min and the duration (mean difference: 2.78 min, P>0.05) were similar in both ensembles. A significant effect for environment (21>30>37°C WBGT, P<0.05) and work intensity (2.5>4>5.5 km.h-1, P< 0.05) was observed in tolerance time. The majority of trials across both ensembles (101/126; 80.1%) were terminated due to participants achieving a heart rate equivalent to greater than 90% of their maximum. Conclusions Physiological tolerance times wearing these two chemical protective undergarments, worn underneath EOD personal protective clothing, were similar and predominantly limited by cardiovascular strain.

Structural and electronic properties of layered arsenic and antimony arsenide

Layered materials exhibit intriguing electronic characteristics and the search for new types of two-dimensional (2D) structures is of importance for future device fabrication. Using state-of-art first principle calculations, we identify and characterize the structural and electronic properties of two 2D layered arsenic materials, namely, arsenic and its alloy AsSb. The stable 2D structural configuration of arsenic is confirmed to be the low-buckled two-dimensional hexagonal structure by phonon and binding energy calculations. The monolayer exhibits indirect semiconducting properties with gap around 1.5 eV (corrected to 2.2 eV by hybrid function), which can be modulated into a direct semiconductor within a small amount of tensile strain. These semiconducting properties are preserved when cutting into 1D nanoribbons, but the band gap is edge dependent. It is interesting to find that an indirect to direct gap transition can be achieved under strain modulation of the armchair ribbon. Essentially the same phenomena can be found in layered AsSb, except a weak Rashba induced band splitting is present in AsSb due to the nonsymmetric structure and spin orbit coupling. When an additional layer is added on the top, a semiconductor–metal transition will occur. The findings here broaden the family of 2D materials beyond graphene and transition metal dichalcogenides and provide useful information for experimental fabrication of new layered materials with possible application in optoelectronics.

The influence of financial risk tolerance and risk perception on individual investment decision-making in a financial advice context

The aim of this thesis is to examine how risk tolerance and risk perception, two important but often misunderstood constructs, jointly influence client investment decisions in a financial advice context. By distinguishing the roles of these two risk constructs in client decision-making, in this thesis a new direction in studying financial/investment risks is provided while practice and regulation in the financial services industry is potentially informed. Based on the literature relating to risks and individual decision-making, a theoretical framework is developed and relevant hypotheses are tested in two studies with financial adviser clients in Australia. Results reveal that financial risk tolerance influences asset allocation both directly and indirectly through risk perception. The intervening role of risk perception suggests that risk tolerance affects how clients perceive the riskiness of an investment product which influences client decision-making.

An evaluation of potential candidate genes involved in salinity tolerance in striped catfish (Pangasianodon hypopthalmus) using an RNA-SEQ approach

The project investigated the molecular response of Tra catfish (Pangasianodon hypophthalmus) to elevated salinity conditions. We employed Next generation sequencing platform to evaluate differential gene expression profiles of key genes under two salinity conditions. Results of the current project can form the basis for further studies to confirm the functional roles of specific genes that influence salinity tolerance in the target species and more broadly in other freshwater teleost fishes. Ultimately, the approach can contribute to developing superior culture stocks of the target species.

Colonoscopy preparation in children: Safety, efficacy, and tolerance of high- versus low-volume cleansing methods

Background: The use of large-volume electrolyte balanced solutions as preparation for colonoscopy often results in poor patient compliance and acceptance. The tolerance, safety, and efficacy of high-versus low volume colon-cleansing methods as preparation for colonoscopy in children were compared by randomized operator-blinded trial. Methods: Twenty-nine children ages 3.6-14.6 years had either high-volume nasogastric balanced polyethylene glycol electrolyte lavage (20 ml/kg/h) until the effluent was clear (n = 15), or two oral doses of sodium phosphate solution (22.5-45 ml) separated by oral fluid intake (n = 14). Results: Both preparations were equally effective. The low-volume preparation was better tolerated and caused less discomfort that the high-volume preparation, judging by serial nurse observations. The incidence of abdominal symptoms, diarrhea, sleep disturbance, and vomiting was not significantly different between the two groups. Both groups had a small reduction in mean hematocrit and serum calcium levels. The sodium phosphate preparation caused increases in mean serum sodium concentrations from 140 to 145 mmol/L and serum phosphate concentrations from 1.41 to 2.53 mmol/L. Ten hours after the commencement of the preanesthetic fast, these concentrations had returned to normal. Conclusions: There are advantages in terms of tolerance, discomfort, and case of administration with acceptable colonic cleansing with the use of the less-invasive oral sodium phosphate low-volume colon-cleansing preparation in children. Safe use requires ensuring an adequate oral fluid intake during the preparation time and avoidance of use in patients with renal insufficiency.

Surface chemical studies of Thiobacillus ferrooxidans with reference to copper tolerance

A strain of Thiobacillus ferrooxidans was adapted to grow at higher concentrations of copper by single step culturing in the presence of 20 g/L (0.314 mol/L) cupric ions added to 9K medium. Exposure to copper results in change in the surface chemistry of the microorganism. The isoelectric point of the adapted strain (pI=4.7) was observed to be at a higher pH than that of the wild unadapted strain(pI=2.0). Compared to the wild strain, the copper adapted strain was found to be more hydrophobic and showed enhanced attachment efficiency to the pyrite mineral. The copper adsorption ability of the adapted strain was also found to be higher than that of the wild strain. Fourier transform infrared spectroscopy of adapted cells suggested that a proteinaceous new cell surface component is synthesized by the adapted strain. Treatment of adapted cells with proteinase-K, resulted in complete loss of tolerance to copper, reduction in copper adsorption and hydrophobicity of the adapted cells. These observations strongly suggest a role played by cell surface modifications of Thiobacillus ferrooxidans in imparting the copper tolerance to the cells and bioleaching of sulphide minerals.

Arsenic trioxide promotes mitochondrial DNA mutation and cell apoptosis in primary APL cells and NB4 cell line

This study aimed to investigate the effects of arsenic trioxide (As2O3) on the mitochondrial DNA (mtDNA) of acute promyelocytic leukemia (APL) cells. The NB4 cell line was treated with 2.0 μmol/L As2O3in vitro, and the primary APL cells were treated with 2.0 μmol/L As2O3in vitro and 0.16 mg kg-1 d-1 As2O3in vivo. The mitochondrial DNA of all the cells above was amplified by PCR, directly sequenced and analyzed by Sequence Navigatore and Factura software. The apoptosis rates were assayed by flow cytometry. Mitochondrial DNA mutation in the D-loop region was found in NB4 and APL cells before As2O3 use, but the mutation spots were remarkably increased after As2O3 treatment, which was positively correlated to the rates of cellular apoptosis, the correlation coefficient: rNB4-As2O3=0.973818, and rAPL-As2O3=0.934703. The mutation types include transition, transversion, codon insertion or deletion, and the mutation spots in all samples were not constant and regular. It is revealed that As2O3 aggravates mtDNA mutation in the D-loop region of acute promyelocytic leukemia cells both in vitro and in vivo. Mitochondrial DNA might be one of the targets of As2O3 in APL treatment.

Fault tolerance in multiprocessor systems

Multiprocessor systems which afford a high degree of parallelism are used in a variety of applications. The extremely stringent reliability requirement has made the provision of fault-tolerance an important aspect in the design of such systems. This paper presents a review of the various approaches towards tolerating hardware faults in multiprocessor systems. It. emphasizes the basic concepts of fault tolerant design and the various problems to be taken care of by the designer. An indepth survey of the various models, techniques and methods for fault diagnosis is given. Further, we consider the strategies for fault-tolerance in specialized multiprocessor architectures which have the ability of dynamic reconfiguration and are suited to VLSI implementation. An analysis of the state-óf-the-art is given which points out the major aspects of fault-tolerance in such architectures.

Phosphorus nutrition and tolerance of cotton to water stress: II. Water relations, free and bound water and leaf expansion rate

In previous experiments, increased leaf-Phosphorus (P) content with increasing P supply enhanced the individual leaf expansion and water content of fresh cotton leaves in a severely drying soil. In this paper, we report on the bulk water content of leaves and its components, free and bound water, along with other measures of plant water status, in expanding cotton leaves of various ages in a drying soil with different P concentrations. The bound water in living tissue is more likely to play a major role in tolerance to abiotic stresses by maintaining the structural integrity and/or cell wall extensibility of the leaves, whilst an increased amount of free water might be able to enhance solute accumulation, leading to better osmotic adjustment and tolerance to water stress, and maintenance of the volumes of sub-cellular compartments for expansive leaf growth. There were strong correlations between leaf-P%, leaf water (total, free and bound water) and leaf expansion rate (LER) under water stress conditions in a severely drying soil. Increased soil-P enhanced the uptake of P from a drying soil, leading to increased supply of osmotically active inorganic solutes to the cells in growing leaves. This appears to have led to the accumulation of free water and more bound water, ultimately leading to increased leaf expansion rates as compared to plants in low P soil under similar water stress conditions. The greater amount of bound and free water in the high-P plants was not necessarily associated with changes in cell turgor, and appears to have maintained the cell-wall properties and extensibility under water stressed conditions in soils that are nutritionally P-deficient.

Phosphorus nutrition and tolerance of cotton to water stress I. Seed cotton yield and leaf morphology

Seed cotton yield and morphological changes in leaf growth were examined under drying soil with different phosphorus (P) concentrations in a tropical climate. Frequent soil drying is likely to induce a decrease in nutrients particularly P due to reduced diffusion and poor uptake, in addition to restrictions in available water, with strong interactive effects on plant growth and functioning. Increased soil P in field and in-ground soil core studies increased the seed cotton yield and related morphological growth parameters in a drying soil, with hot (daily maximum temperature >33°C) and dry conditions (relative humidity, 25% to 35%), particularly during peak boll formation and filling stage. The soil water content in the effective rooting zone (top 0.4 m) decreased to -1.5 MPa by day 5 of the soil drying cycle. However, the increased seed cotton yield for the high-P plants was closely related to increasing leaf area with increased P supply. Plant height, leaf fresh mass and leaf area per plant were positively related to the leaf P%, which increased with increasing P supply. Low P plants were lower in plant height, leaf area, and leaf tissue water in the drying soil. Individual leaf area and the water content of the fresh leaf (ratio of dry mass to fresh mass) were significantly dependent on leaf P%.

Measurement and Interpretation of Salinity Tolerance in Four Perennial Grasses

Whilst the topic of soil salinity has received a substantive research effort over the years, the accurate measurement and interpretation of salinity tolerance data remain problematic. The tolerance of four perennial grass species (non-halophytes) to sodium chloride (NaCl) dominated salinity was determined in a free-flowing sand culture system. Although the salinity tolerance of non-halophytes is often represented by the threshold salinity model (bent-stick model), none of the species in the current study displayed any observable salinity threshold. Further, the observed yield decrease was not linear as suggested by the model. On re-examination of earlier datasets, we conclude that the threshold salinity model does not adequately describe the physiological processes limiting growth of non-halophytes in saline soils. Therefore, the use of the threshold salinity model is not recommended for non-halophytes, but rather, a model which more accurately reflects the physiological response observed in these saline soils, such as an exponential regression curve.

EXAFS studies of arsenic chalcogenide glasses

An EXAFS study at the AsK edge of the ternary glasses As2(S, Se)3 and As2(Se, Te)3 and the binary As2S3, As2Se3 and As2Te3 glasses has been carried out. Radial structure functions show that the environment of As in glasses of intermediate compositions is quite different from that in the binary glasses. In the As2(S, Se)3 system, this might arise from chemical disorder in the network while in the As2(Se, Te)3 system increased ionicity could be the cause of this behaviour. Glasses where the constituent atoms are of similar size seem to exhibit fewer peaks in the radial structure function.