http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6990 A potassium chloride-containing salt substitute lowers blood pressure levels, but its overall acceptability has been of concern due to its potential adverse effects on food taste. In a large-scale, blinded randomised trial evaluating the comparative effects of a salt substitute (65% sodium chlofide, 25% potassium chloride and 10% magnesium sulphate) and a normal salt (100% sodium chloride) on blood pressure, we collected data on the saltiness, flavour and overall acceptability of food. We performed this at baseline, 1, 6 and 12 months post-randomisation using 100 mm visual analogue scales for assessments of both home-cooked foods and a standard salty soup. The mean age of the 608 participants from rural northern China was 60 years and 56% of them were females. In the primary analyses, the changes in the saltiness, flavour and overall acceptability of both home-cooked foods and a standard salty soup were not different between the randomised groups (all P>0.08). In the secondary analyses, weighting each of the data points according to the lengths of the respective follow-up intervals, the flavour of both home-cooked foods (mean difference = -1.8 mm, P=0.045) and a standard salty soup (mean difference = -1.9mm, P=0.03) was slightly weaker in the salt substitute group. We conclude that salt substitution is both an effective and an acceptable means of blood pressure control. Possible small differences in flavour did not importantly deter the use of the salt substitute in this study group, although the acceptability of the salt substitute by a more general population group would need to be confirmed. 2012-01-30T05:04:13.420Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8125 Background & aims: Reducing dietary salt intake is a health promotion priority. This is particularly important in persons with kidney disease. Food surveys indicate that UK South Asian populations have high salt intakes, yet little is known of the cooking and eating habits of these groups. The aim of this study was to explore and describe salt-related dietary practices of Bangladeshi chronic renal failure patients. Methods: Case study methodology was employed with 10 Bangladeshi renal patients and their partners in East London. Understanding of the processes of preparation and consumption of the mid-day meal within the cultural context was the phenomenon of interest; mixed methods including non-participant observation, interviews and weighed food analysis were used. Results: The typical Bangladeshi meal comprised two meat, one lentil and one vegetable dish. Two such meals a day were eaten. These provided a mean 10 g salt/day from two main meals, plus more from breakfast and snacks. Salt was added during cooking and to meals in various other ways. Conclusions: These findings reveal opportunities and information to support development of collaborative, culturally sensitive health promotion education. 2011-07-06T04:30:11.153Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:4820 A production protocol for an aggregated casein mass has been developed and the effect of NaCl concentration on the yield, texture, and rheology has been evaluated. Concentrations of NaCl up to 20mM lead to greater yield however, higher concentrations were detrimental. A similar pattern was observed for adhesiveness, one of the texture profile parameters measured. Other parameters such as hardness, cohesiveness, work and gumminess could only differentiate the 30mM NaCl-containing aggregate, but for concentrations 0-20mM differences were not significant. Small deformation rheological testing confirmed that excess salt had a weakening effect on the aggregated casein mass. Comparison of the aggregated casein ingredient with gluten revealed a very different behaviour upon heating. Gluten remained relatively unaffected while the aggregated casein masses became more viscous with increasing temperature, since the effect of heating was much greater on the elastic modulus than on the viscous. 2010-12-02T02:00:22.872Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6612 Two types of saline water exist on Earth, namely marine waters, including brackish zones of mixing with fresh water, and epicontinental salt lakes. This chapter addresses the values, threats and likely future of salt lakes, which are here defined as permanent or temporary bodies of water with salinities >3 g per litre and lacking any recent connection to the marine environment (i.e. athalassohaline sensu Bayly 1967). 2010-09-10T01:00:08.250Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2345 Recent developments in long term landform evolution modelling have created a new demand for quantitative salt weathering data, and in particular data describing the size distribution of the weathered rock fragments. To enable future development of rock breakdown models for use in landscape evolution and soil production models, laboratory work was undertaken to extend existing schist/salt weathering fragmentation studies to include an examination of the breakdown of sub-millimetre quartz chlorite schist particles in a seasonally wet tropical climate. Laser particle sizing was used to assess the impact of different experimental procedures on the resulting particle size distribution. The results reveal that salt weathering under a range of realistic simulated tropical wet season conditions produces a significant degree of schist particle breakdown. The fragmentation of the schist is characterized by splitting of the larger fragments into mid-sized product with finer material produced, possibly from the breakdown of mid-sized fragments when weathering is more advanced. Salinity, the salt addition method and temperature were all found to affect weathering rates. Subtle differences in mineralogy also produce variations in weathering patterns and rates. It is also shown that an increase in drying temperature leads to accelerated weathering rates, however, the geometry of the fracture process is not significantly affected. 2010-04-27T06:46:40.178Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:895 Mid-latitude winter atmospheric variability in the South Indian Ocean and southwest Pacific Ocean regions of the circum-Antarctic are reconstructed using sea-salt aerosol concentrations measured in the high resolution Law Dome (DSS) ice core from East Antarctica. The sea-salt aerosol concentration data, as sodium (Na), were measured at approximately monthly resolution spanning the past 700 years. Analyses of covariations between Na concentrations in Law Dome ice, and mean sea-level pressure (MSLP) and wind field data were conducted to define the mid-latitude and sub-Antarctic atmospheric circulation patterns associated with variations in Na delivery. High Na concentrations in Law Dome snow are associated with increased meridional aerosol transport from mid-latitude sources. The seasonal average Na concentration for early winter (May, June, July (MJJ)) is strongly correlated to the mid-latitude MSLP field in the South Indian and southwest Pacific Oceans, and southern Australian regions. In addition, the average MJJ Na concentrations display a strong association with the stationary Rossby wave number 3 circulation, and are anti-correlated to the Southern Annular Mode (SAM) index of climate variability: high (low) Na concentrations occurring during negative (positive) SAM phases. This observed relationship is used to derive a proxy record for early-winter MSLP anomalies and the SAM in the South Indian and southwest Pacific Ocean regions over the period 1300–1995 AD. The proxy SAM index from 1300 to 1995 AD shows pronounced decadal-scale variability throughout. The period after 1500 AD is marked by a tendency toward slower variations and a weakly-positive mean SAM (enhanced westerlies in the 50° to 65°S zone) compared to the early part of the record. 2010-04-27T06:41:42.095Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1182 Medicago truncatula, a model for legume genomics, can be regenerated by somatic embryogensis by the use of a suitable genotype and an auxin plus cytokinin. The stress response induced by explant wounding and culture is increasingly recognized as an important component of somatic embryo induction. We have cloned and investigated the stress kinase gene MtSK1 in relation to somatic embryogenesis in M. truncatula, using the highly embryogenic mutant Jemalong 2HA (2HA) and its progenitor Jemalong. The main features of the MtSK1 protein of 351 amino acids are an N-terminal kinase domain and a C-terminal glutamic acid-rich region, which is predicted to be a coiled-coil. MtSK1 is a member of the SnRK2 subgroup of the SnRK group of plant kinases. Members of the SnRK2 kinases play a role in stress responses of plants. MtSKI expression is induced by wounding in the cultured tissue independent of auxin or cytokinin. However, in both 2HA and Jemalong, as the callus develops in response to auxin plus cytokinin, MtSK1 expression continues to increase. MtSK1 responds to salt stress in vivo, consistent with its role as a stress kinase. The likely role of MtSK1 in stress-induced signaling will facilitate the relating of stress–response pathways to auxin and cytokinin-induced signaling in the understanding of the molecular mechanisms involved in the induction of somatic embryogenesis in M. truncatula. 2010-04-27T06:38:09.151Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:865 Data describing sediment generation focusing on the temporal evolution of size gradation are required for the prediction of long-term landform evolution. This paper presents such data for the salt weathering of a quartz-chlorite schist obtained from the Ranger Uranium Mine in northern Australia. Rock fragment samples are subjected to three different climate regimes: (1) a dry season climate; (2) a wet season climate (both based on observations at the Ranger site); and (3) an oven-drying sequence designed to test the sensitivity of the weathering process by exposing the rocks to more extreme temperatures. Two MgSO4 salt solutions are applied, one being typical of wet season runoff and the other a more concentrated solution. Salt solution is applied daily in the wet season experiments and once only at the beginning of the dry season experiments. Results of the experiments reveal four stages of weathering. The kinetics of each stage are described and related to the formation of sediment of different sizes. Wet season climate conditions are shown to produce greater moisture variability and lead to faster weathering rates. However, salt concentrations in the wet season are typically lower and so when climate is combined with observed salt concentrations, the dry and wet season experiments weather at approximately equal rates. Finally, small variations in rock properties were shown to have a large impact on weathering rates, leading to the conclusion that rock weathering experiments need to be carefully designed if results are to be used to help predict weathering behaviour at the landscape scale 2010-04-27T06:23:08.851Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:603 Long-term weathering or a quartz chlorite schist via wetting and drying was studied under a simulated tropical climate. Cubic rock samples (15 mm x 15 mm x 15 mm) were cut from larger rocks and subjected to time-compressed climatic conditions simulating the tropical wet season climate at the Ranger Uranium Mine in the Northern Territory, Australia. Fragmentation, moisture content and moisture uptake rate were monitored over 5000 cycles of wetting and drying. To determine the impact of climatic variables, five climatic regimes were simulated, varying water application, temperature and drying. One of the climatic regimes reproduced observed temperature and moisture variability at the Ranger Uranium Mine, but over a compressed time scale. It is shown that wetting and drying is capable of weathering quartz chlorite schist with changes expected over a real time period of decades. While wetting and (Irving alone does produce changes to rock morphology, the incorporation of temperature variation further enhances weathering rates. Although little fragmentation occurred in experiments, significant changes to internal pore structure were observed, which could potentially enhance other weathering mechanisms. Moisture variability is shown to lead to higher weathering rates than are observed when samples are subjected only to leaching. Finally, experiments were conducted on two rock samples from the same source having only subtle differences in mineralogy. The samples exhibited quite different weathering rates leading to the conclusion that our knowledge of the role of rock type and composition in weathering is insufficient for the accurate determination of weathering rates. 2010-04-27T05:42:45.575Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:41 Lucigenin-dependent chemiluminescence together with 2-[4-iodophenyl]-3-[4-nitrophenyl]-5-[2,4-disulfophenyl]-2H tetrazolium monosodium salt (WST-1) reduction can be detected following addition of NADH to many cell types, including human sperm suspensions. Although many reports suggest that such a phenomenon is due to reactive oxygen species production, other oxygen detecting metabolite probes, such as MCLA and luminol, do not produce a chemiluminescent signal in this model system. The enzyme responsible for NADH-dependent lucigenin chemiluminescence was purified and identified as cytochrome-b5 reductase. In support of this concept, COS-7 cells overexpressing cytochrome-b5 reductase displayed at least a 3-fold increase in the previously mentioned activity compared with mock-transfected cells. Fractions containing cytochrome-b5 reductase were capable of inducing both lucigenin-dependent chemiluminescence and WST-1 reduction. Oxygen radicals clearly did not mediate the cytochrome b5-mediated activation of these probes in vitro since neither luminol nor MCLA gave a chemiluminescence response in the presence of the enzyme and the cofactor NADH. These results emphasize the importance of the direct NADH-dependent reduction of these putative superoxide-sensitive probes by cytochrome-b5 reductase even though this enzyme does not, on its own accord, produce reactive oxygen species. 2010-04-27T05:35:12.625Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:3472 Three different types of aggregates of submicron alumina particles were produced utilising either polymer, high salt (1.0 M), or low salt (0.075 M) aggregation conditions. All three types of aggregates had similar structural properties (mass fractal dimension = 2.0). The typical size (d[4,3]) of the polymer aggregates was 125 microns, the high salt aggregates 12 microns and the low salt aggregates 4 microns. It was found that smaller aggregates produced higher gel points and higher apparent maximum packing fractions. Larger aggregates produced higher shear and compressive yield stresses at all volume fractions. The relative effect that aggregate size and inter-particle attraction has on the sediment yield stresses was investigated in the salt system. The salt concentration was adjusted so as to produce different size aggregates with the same final salt concentration and thus same level of inter-particle attraction. The size of the aggregates and the magnitude of the inter-particle attraction were found to have similar contributions to the compressive yield stress over the range of size and attraction investigated. 2010-04-27T05:29:46.841Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:3414 Recent developments in long term landform evolution modelling have created a new demand for quantitative salt weathering data, and in particular data describing the size distribution of the weathered rock fragments. To enable future development of rock breakdown models for use in landscape evolution and soil production models, laboratory work was undertaken to extend existing schist/salt weathering fragmentation studies to include an examination of the breakdown of sub-millimetre quartz chlorite schist particles in a seasonally wet tropical climate. Laser particle sizing was used to assess the impact of different experimental procedures on the resulting particle size distribution. The results reveal that salt weathering under a range of realistic simulated tropical wet season conditions produces a significant degree of schist particle breakdown. The fragmentation of the schist is characterized by splitting of the larger fragments into mid-sized product with finer material produced, possibly from the breakdown of mid-sized fragments when weathering is more advanced. Salinity, the salt addition method and temperature were all found to affect weathering rates. Subtle differences in mineralogy also produce variations in weathering patterns and rates. It is also shown that an increase in drying temperature leads to accelerated weathering rates, however, the geometry of the fracture process is not significantly affected. 2010-04-27T05:01:31.470Z ]]>