Noninvasive localization of petroleum-derived spray oil in plants with chemical shift selective magnetic resonance imaging

Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) were used to detect petroleum-derived spray oils (PDSOs) in citrus seedlings and trees. The NMR spectrum of the phantom containing 10% (v/v) of a nC24 agricultural mineral oil (AMO) showed the resonance of the water protons at delta = 5 ppm, while the resonance of the oil protons at delta = 1.3 to 1.7 ppm. The peak resolution and the chemical shift difference of more than 3.3 ppm between water and oil protons effectively differentiated water and the oil. Chemical shift selective imaging (CSSI) was performed to localize the AMO within the stems of Citrus trifoliata L. seedlings after the application of a 4% (v/v) spray. The chemical shift selective images of the oil were acquired by excitation at delta = 1.5 ppm by averaging over 400 transients in each phase-encoding step. Oil was mainly detected in the outer cortex of stems within 10 d of spray application; some oil was also observed in the inner vascular bundle and pith of the stems at this point. CSSI was also applied to investigate the persistence of oil deposits in sprayed mature Washington navel orange (Citrus x aurantium L.) trees in an orchard. The trees were treated with either fourteen 0.25%, fourteen 0.5%, four 1.75%, or single 7% sprays of a nC23 horticultural mineral oil (HMO) 12 to 16 months before examination of plant tissues by CSSI, and were still showing symptoms of chronic phytotoxicity largely manifested as reduced yield. The oil deposits were detected in stems of sprayed flushes and unsprayed flushes produced 4 to 5 months after the last spray was applied, suggesting a potential movement of the oil via phloem and a correlation of the persistence of oil deposit in plants and the phytotoxicity. The results demonstrate that MRI is an effective method to probe the uptake and localization of PDSOs and other xenobiotics in vivo in plants noninvasively and nondestructively.

Expression analysis of a human hepatic cell line in response to palmitate

Saturated fat plays a role in common debilitating diseases such as obesity, type 2 diabetes, and coronary heart disease. It is also clear that certain fatty acids act as regulators of metabolism via both direct and indirect signalling of target tissues. As the molecular mechanisms of saturated fatty acid signalling in the liver are poorly defined, hepatic gene expression analysis was undertaken in a human hepatocyte cell line after incubation with palmitate. Profiling of mRNA expression using cDNA microarray analysis revealed that 162 of approximately 18,000 genes tested were differentially expressed after incubation with palmitate for 48 h. Altered transcription profiles were observed in a wide variety of genes, including genes involved in lipid and cholesterol transport, cholesterol catabolism, cell growth and proliferation, cell signalling, P-oxidation, and oxidative stress response. While palinitate signalling has been examined in pancreatic beta-cells, this is the first report showing that palmitate regulates expression of numerous genes via direct molecular signalling mechanisms in liver cells. (C) 2005 Elsevier Inc. All rights reserved.

Effect of seasonal variation and storage temperature on leaf chlorophyll fluorescence and vase life of cut roses

Low temperature injury (LTI) of roses (Rosa hybrida L.) is difficult to assess by visual observation. Relative chlorophyll fluorescence (CF; F-v/F-m) is a non-invasive technique that provides an index of stress effects on photosystem 11 (PS 11) activity. This instrumental technique allows determination of the photosynthetic efficiency of plant tissues containing chloroplasts, such as rose leaves. In the present study, pre- and Post-Storage measurements of F-v/F-m were carried out to assess LTI in 'First Red' and 'Akito' roses harvested year round. Relationships between the pre-harvest environment conditions of temperature, relative humidity and photon flux density (PFD), F-v/F-m, and, vase life duration after storage are reported. After harvest, roses were stored at 1, 5 and 10 degrees C for 10 days. Non-stored roses were the control treatment. F-v/F-m ratios were reduced following storage, suggesting LTI of roses. However, reductions in F-v/F-m were not closely correlated with reduced vase life duration and were seasonally dependent. Only during winter experiments was F-v/F-m of roses stored at 1 degrees C significantly (P <= 0.001) lower compared to F-v/F-m of non-stored control roses and roses stored at 5 and 10 degrees C. Thus, the fall of F-v/F-m was due to an interaction of growing season and storage at 1 degrees C. Vase lives of roses grown during winter were significantly (P <= 0.001) shorter compared to roses grown during summer. Length of vase life was intermediate for roses grown during autumn and spring. Because of the lack of correlation between F-v/F-m and post-storage vase life it is concluded that the CF parameter F-v/F-m is nota practical index for assessing LTI in cold-stored roses. Higher PFD and temperature in summer were positively and significantly correlated with maintenance of post-storage FvIF ratios and longer vase life. It is suggested that shorter vase lives and lower post-storage F-v/F-m values after storage at 1 degrees C are consequences of reduced photosynthesis and smaller carbohydrate pools in winter-harvested roses. (c) 2004 Elsevier B.V All rights reserved.

The impact of neurodynamic testing on the perception of experimentally induced muscle pain

Neurodynamic tests such as the straight leg raising (SLR) and slump test are frequently used for assessment of mechanosensitivity of neural tissues. However, there is ongoing debate in the literature regarding the contributions of neural and non-neural tissues to the elicited symptoms because many structures are affected by these tests. Sensitizing manoeuvres are limb or spinal movements added to neurodynamic tests, which aim to identify the origin of the symptoms by preferentially loading or unloading neural structures. A prerequisite for the use of sensitizing manoeuvres to identify neural involvement is that the addition of sensitizing manoeuvres has no impact on pain perception when the origin of the pain is non-neural. In this study, experimental muscle pain was induced by injection of hypertonic saline in tibialis anterior or soleus in 25 asymptomatic, naive volunteers. A first experiment investigated the impact of hip adduction, abduction, medial and lateral rotation in the SLR position. In a second experiment, the different stages of the slump test were examined. The intensity and area of experimentally induced muscle pain did not increase when sensitizing manoeuvres were added to the SLR or throughout the successive stages of the slump test. The findings of this study lend support to the validity of the use of sensitizing manoeuvres during neurodynamic testing. (C) 2004 Elsevier Ltd. All rights reserved.

Development of a non-intrusive heat transfer coefficient gauge and its application to high pressure die casting Effect of the process parameters

A heat transfer coefficient gauge has been built, obeying particular rules in order to ensure the relevance and accuracy of the collected information. The gauge body is made out of the same materials as the die casting die (H13). It is equipped with six thermocouples located at different depths in the body and with a sapphire light pipe. The light pipe is linked to an optic fibre, which is connected to a monochromatic pyrometer. Thermocouples and pyrometer measurements are recorded with a data logger. A high pressure die casting die was instrumented with one such gauge. A set of 150 castings was done and the data recorded. During the casting, some process parameters have been modified such as piston velocity, intensification pressure, delay before switch to the intensification stage, temperature of the alloy, etc.... The data was treated with an inverse method in order to transform temperature measurements into heat flux density and heat transfer coefficient plots. The piston velocity and the initial temperature of the die seem to be the process parameters that have the greatest influence on the heat transfer. (c) 2005 Elsevier B.V. All rights reserved.

Pore size distribution analysis of activated carbons: Application of density functional theory using nongraphitized carbon black as a reference system

The application of nonlocal density functional theory (NLDFT) to determine pore size distribution (PSD) of activated carbons using a nongraphitized carbon black, instead of graphitized thermal carbon black, as a reference system is explored. We show that in this case nitrogen and argon adsorption isotherms in activated carbons are precisely correlated by the theory, and such an excellent correlation would never be possible if the pore wall surface was assumed to be identical to that of graphitized carbon black. It suggests that pore wall surfaces of activated carbon are closer to that of amorphous solids because of defects of crystalline lattice, finite pore length, and the presence of active centers.. etc. Application of the NLDFT adapted to amorphous solids resulted in quantitative description of N-2 and Ar adsorption isotherms on nongraphitized carbon black BP280 at their respective boiling points. In the present paper we determined solid-fluid potentials from experimental adsorption isotherms on nongraphitized carbon black and subsequently used those potentials to model adsorption in slit pores and generate a corresponding set of local isotherms, which we used to determine the PSD functions of different activated carbons. (c) 2005 Elsevier Ltd. All rights reserved.

Dissolution of porcine incisor pulps in sodium hypochlorite solutions of varying compositions and concentrations

Background: The solubility of dental pulp tissue in sodium hypochlorite has been extensively investigated but results have been inconsistent; due most likely to variations in experimental design, the volume and/or rate of replenishment of the solutions used and the nature of the tissues assessed. Traditionally, the sodium hypochlorite solutions used for endodontic irrigation in Australia have been either Milton or commercial bleach, with Milton being the most common. Recently, a range of Therapeutic Goods Administration (TGA) approved proprietary sodium hypochlorite solutions, which contain surfactant, has become available. Some domestic chlorine bleaches now also contain surfactants. The purpose of this study was to perform new solubility assessments, comparing Milton with new TGA approved products, Hypochlor 1% and Hypochlor 4% forte, and with a domestic bleach containing surfactant (White King). Methods: Ten randomly assigned pulp samples of porcine dental pulp of approximately equal dimensions were immersed in the above solutions, as well as representative concentrations of sodium hydroxide. Time to complete dissolution was measured and assessed statistically. Results: White King 4% showed the shortest dissolution time, closely followed by Hypochlor 4% forte. White King 1% and Hypochlor 1% each took around three times as long to completely dissolve the samples of pulp as their respective 4% concentrations, while Milton took nearly 10 times as long. The sodium hydroxide solutions showed no noticeable dissolution of the pulp samples. Conclusions: The composition and content of sodium hypochlorite solutions had a profound effect on the ability of these solutions to dissolve pulp tissue in vitro. Greater concentrations provided more rapid dissolution of tissue. One per cent solutions with added surfactant and which contained higher concentrations of sodium hydroxide were significantly more effective in dissolution of pulp tissue than Milton.

A side order of stem cells: The SP phenotype

A defining property of murine hematopoietic stein cells (HSCs) is low fluorescence after staining with Hoechst 33342 and Rhodamine 123. These dyes have proven to be remarkably powerful tools in the purification and characterization of HSCs when used alone or in combination with antibodies directed against stem cell epitopes. Hoechst low cells are described as side population (SP) cells by virtue of their typical profiles in Hoechst red versus Hoechst blue bivariate fluorescent-activated cell sorting dot plots. Recently, excitement has been generated by the findings that putative stem cells from solid tissues may also possess this SP phenotype. SP cells have now been isolated from a wide variety of mammalian tissues based on this same dye efflux phenomenon, and in many cases this cell population has been shown to contain apparently multipotent stem cells. What is yet to be clearly addressed is whether cell fusion accounts for this perceived SP multipotency. Indeed, if low fluorescence after Hoechst staining is a phenotype shared by hematopoietic and organ-specific stem cells, do all resident tissue SP cells have bone marrow origins or might the SP phenotype be a property common to all stem cells? Subject to further analysis, the SP phenotype may prove invaluable for the initial isolation of resident tissue stem cells in the absence of definitive cell-surface markers and may have broad-ranging applications in stem cell biology, from the purification of novel stem cell populations to the development of autologous stem cell therapies.

Coupled thermal, structural and vibrational analysis of a hypersonic engine for flight test

This paper describes a relatively simple and quick method for implementing aerodynamic heating models into a finite element code for non-linear transient thermal-structural and thermal-structural-vibrational analyses of a Mach 10 generic HyShot scramjet engine. The thermal-structural-vibrational response of the engine was studied for the descent trajectory from 60 to 26 km. Aerodynamic heating fluxes, as a function of spatial position and time for varying trajectory points, were implemented in the transient heat analysis. Additionally, the combined effect of varying dynamic pressure and thermal loads with altitude was considered. This aero-thermal-structural analysis capability was used to assess the temperature distribution, engine geometry distortion and yielding of the structural material due to aerodynamic heating during the descent trajectory, and for optimising the wall thickness, nose radius of leading edge, etc. of the engine intake. A structural vibration analysis was also performed following the aero-thermal-structural analysis to determine the changes in natural frequencies of the structural vibration modes that occur at the various temperatures associated with the descent trajectory. This analysis provides a unique and relatively simple design strategy for predicting and mitigating the thermal-structural-vibrational response of hypersonic engines. (C) 2006 Elsevier SAS. All rights reserved.

Experimental validation of the regulated expression of large numbers of non-coding RNAs from the mouse genome

Recent large-scale analyses of mainly full-length cDNA libraries generated from a variety of mouse tissues indicated that almost half of all representative cloned sequences did flat contain ail apparent protein-coding sequence, and were putatively derived from non-protein-coding RNA (ncRNA) genes. However, many of these clones were singletons and the majority were unspliced, raising the possibility that they may be derived from genomic DNA or unprocessed pre-rnRNA contamination during library construction, or alternatively represent nonspecific transcriptional noise. Here we Show, using reverse transcriptase-dependent PCR, microarray, and Northern blot analyses, that many of these clones were derived from genuine transcripts Of unknown function whose expression appears to be regulated. The ncRNA transcripts have larger exons and fewer introns than protein-coding transcripts. Analysis of the genomic landscape around these sequences indicates that some cDNA clones were produced not from terminal poly(A) tracts but internal priming sites within longer transcripts, only a minority of which is encompassed by known genes. A significant proportion of these transcripts exhibit tissue-specific expression patterns, as well as dynamic changes in their expression in macrophages following lipopolysaccharide Stimulation. Taken together, the data provide strong support for the conclusion that ncRNAs are an important, regulated component of the mammalian transcriptome.

Fluorescence in situ hybridization and spectral imaging of coral-associated bacterial communities

Microbial communities play important roles in the functioning of coral reef communities. However, extensive autofluorescence of coral tissues and endosymbionts limits the application of standard fluorescence in situ hybridization (FISH) techniques for the identification of the coral-associated bacterial communities. This study overcomes these limitations by combining FISH and spectral imaging.

The DVD animal model of schizophrenia: Effects of low maternal vitamin D on brain dopamine

Background: We have previously shown that the offspring of vitamin D3 depleted rats have enlarged ventricles and altered neurotrophin profiles (reduced NGF and GDNF). These findings enhance the biological plausibility that low prenatal vitamin D may be a risk factor for schizophrenia. Our recent behavioural studies have found that adult rats with developmental vitamin D deficiency (DVD) have a subtle increase in baseline locomotor activity and a heightened response to dopamine (DA) antagonists. The aim of this study was to investigate brain DA neurochemistry in the DVD model. Methods: We examined cerebrums and striatal tissue from neonates and a variety of brain tissues from the remaining littermates at adulthood. DA, DOPAC, HVA, serotonin and 5HIAA were analysed by HPLC. Single point comparisons for DA1, DA2 and NMDA receptors were also assessed in these tissues. Results: Significant increases in DA and HVA were found in brains from DVD deplete neonates (P=0.01). However, DA and its metabolites were not increased in either the neonate or adult striatum, however there was a trend towards increased DA and its metabolites in the accumbens (P=0.1). Receptor densities were unaffected by prenatal vitamin D levels. Conclusions: Although the effect of maternal diet appears to increase DA production and turnover in neonatal brain, this does not persist into adulthood. Thus other factors must underlie the increased locomotor activity noted in these animals. Future experiments will concentrate on monitoring accumbens and striatal DA release and turnover using microdialysis in pharmacologically challenged behavioural paradigms. References: Eyles D, Brown J; Mackay-Sim A, McGrath J, Feron F. (2003) Vitamin D3 and brain development. Neuroscience 118 (3) 641–653. Burne T, McGrath J, Eyles D, Mackay-Sim A. Behavioural characterization of vitamin D receptor knockout mice. (2005) Behavioural Brain Res: 157 299–308.

Transpiration efficiency in a segregating population of sunflower: Inheritance, correlation with other traits and association with hybrid grain yield

Plants incorporate isotopes of carbon into their tissue at different rates because of discrimination against 13C relative to 12C during photosynthesis. This difference in discrimination has been negatively correlated with transpiration efficiency (TE) in many C3 species and so, carbon isotope discrimination (Δ) of leaf tissues has been proposed as a potential tool for selecting genotypes with improved performance under water limited conditions. The relationship between Δ and TE in sunflower has been described previously using diverse genotypes, but this relationship has not been investigated with material selected from a segregating population. In this study, the TE of twenty recombinant inbred lines from a population (HAR4 x SA52) segregating for Δ was evaluated in a rainout shelter experiment. A strong negative genetic correlation between TE and Δ was observed (rg = -0.58), confirming previous studies of sunflower with unrelated lines. In addition, TE was strongly correlated to plant height at the final harvest (rg = 0.64) and TDW (rg = 0.58), and moderately correlated to SLW (rg = 0.46) and SPAD (rg = 0.21) but not leaf number (rg = 0.02). Estimates of narrow sense heritability of TE and Δ were very high (0.82 and 0.77, respectively) suggesting that selection for these traits could occur in early generations of segregating populations. Grain yield evaluations under field conditions of hybrids contrasting for Δ showed that low Δ (high TE) hybrids had a yield advantage between 22-35% in dry environments where the yield was less than 2t/ha. While this level of yield advantage may not be realized in commercial breeding programs, computer simulations suggest that 10-15% yield improvements may be possible. Low Δ material selected from the population HAR4 x SA52 has been distributed to private seed companies for further evaluation.

Dietary and nutritional aspects of tooth wear

There is a general perception that the problem of tooth wear is increasing due to elements of the modern diet and due to increased retention of dentition into older age. Tooth wear encompasses erosion, abrasion and attrition of dental tissues – these often co-exist – yet in general, erosion is of more significance to the young and attrition is of more significance to the older population. Diet plays a significant role in the aetiology of tooth wear and likewise advanced tooth wear in older age may impose dietary restrictions with consequences for dietary intake and nutritional status. There is a need to increase the awareness of the disease of tooth wear and the associated nutritional problems. At present, the aetiology of tooth wear is poorly understood – especially with respect to the role of diet. Clearer information on how best to measure and monitor the incidence and prevalence is needed in order to obtain longitudinal data on trends in tooth wear and to monitor the factors that contribute to this condition. These issues will be addressed in the following presentations: 1) What is tooth wear? Aetiology, measurement and monitoring, 2) The role of diet in the aetiology of dental erosion, 3) Groups at increased risk of tooth wear: Eating disorders, ‘dieters' sportsmen and those with impairments, 4) Tooth wear in older adults: nutritional implications. In summary this symposium seeks to: 1) increase awareness of the disease of tooth wear, and its associated nutritional problems 2) increase understanding of the aetiology of tooth wear, especially the dietary role, 3) provide information on how to measure and monitor tooth wear, 4) highlight future research requirements in the area of tooth wear and diet.

Clustering patterns of neurofibrillary tangles in Alzheimer’s disease

Clustering of cellular neurofibrillary tangles (NFT) was studied in the cerebral cortex and hippocampus in cases of Alzheimer’s disease (AD) using a regression method. The objective of the study was to test the hypothesis that clustering of NFTs reflects the degeneration of the cortico-cortical pathways. In 25/38 (66%) of analyses of individual brain areas, a significant peak to trough and peak to peak distance was obtained suggesting that the clusters of NFTs were regularly distributed in bands parallel to the tissue boundary. In analyses of cortical tissues with regularly distributed clusters, peak to peak distance was between 1000 and 1600 microns in 13/24 (54%) of analyses, >1600 microns in 10/24 (42%) and <1000 microns in 1/24 (4%) of analyses. A regular distribution of NFT clusters was less evident in the CA sectors of the hippocampus than in the cortex. Hence, in a significant proportion of brain areas, the spacing of NFT clusters along the cerebral cortex was consistent with the predicted distribution of the cells of origin of specific cortico-cortical projections. However, in many brain regions, the sizes of the NFT clusters were larger than predicted which may be attributable to the spread of NFTs to adjacent groups of cells as the disease progresses.