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Selected AbstractsRecovery of bird populations after clearfelling of tall open eucalypt forest in Western AustraliaJOURNAL OF APPLIED ECOLOGY, Issue 5 2001M.R. Williams Summary 1Increasing concern over the sustainable management of forested landscapes and the extent of forest clearance world-wide has led to a growing interest in the impacts of logging and associated habitat disturbance on biodiversity. 2We conducted an experimental study of the impact of clearfelling on birds of the karri Eucalyptus diversicolor forest in south-west Western Australia over a 17-year period, and a retrospective study of both clearfelled and naturally regenerated karri stands aged from 0 to 146 years. 3One-third of species still had significantly reduced abundance 14 years after disturbance ceased, although all affected species made limited use of regenerating forest. 4Multivariate analysis of changes in bird community structure showed that the effects of disturbance were still evident 14 years after clearfelling. Clearfelling may also have produced some temporary changes in community structure in adjacent unlogged forest. 5Species richness and total abundance of birds declined by 58% and 96%, respectively, in the first year after clearfelling, and 14 years after logging were still 17% and 55% below levels in adjacent undisturbed forest. During this early successional phase both measures increased as a simple function of stand age. Species richness of regrowth reached that of old-growth at 30,50 years and total abundance of all bird species in regrowth was similar to that of old-growth after approximately 70 years. 6Several bird species offer potential as indicators of the ecological sustainability of karri forest management. These species nest in large hollows in standing live trees (two cockatoo species) or have been slow to recolonize immature regrowth karri forests (six species). 7Post-hoc power analysis showed that even the long-term and intensive sampling employed in this study failed to detect declines in abundance of less than 80,90% for most bird species. For many uncommon species, trying to estimate changes in abundance is problematic and likely to require replication which is difficult to achieve in field situations where logged and unlogged forests are compared. Despite this, the present study identified some key impacts of forest clearfelling on bird communities, with implications both for the consequences of clearfelling of forests and the criteria for sustainable forest management. [source] Surface roughness measurements as a method for tribological characterisation of ball bearingsLUBRICATION SCIENCE, Issue 4 2001D. Delfosse Abstract A series of experiments using steel or hybrid balls in an SNFA VEX25 type bearing was conducted, at a rotational speed of 50,000 rpm. The race material was 100Cr6 steel, whereas for the balls various steels, coatings, and ceramics were used. The different materials used for the balls as well as the method of lubrication (air/oil or grease) strongly influenced the surface degradation of the ball bearings. Hybrid bearings with ceramic balls showed very little wear of either the balls or the steel races, and so offer potential for high-speed applications. The degradation of the bearings was examined using scanning electron microscopy, atomic force microscopy, and laser scanning profilometry. The disadvantages and advantages of these methods are given, along with the results of surface roughness measurements. [source] Growth factors improve gene expression after lentiviral transduction in human adult and fetal hepatocytesTHE JOURNAL OF GENE MEDICINE, Issue 2 2007Clare Selden Abstract Background Lentiviral vectors may be vectors of choice for transducing liver cells; they mediate integration in quiescent cells and offer potential for long-term expression. In adult liver, hepatocytes are generally mitotically quiescent. There has been controversy as to the necessity for lentiviral vector target cells to be in the cell cycle; currently, there is consensus that effective transduction can be achieved in quiescent hepatocytes, by using virus at high titre. However, transduction approaches which reduce the multiplicities of infection (MOIs) required provide potential benefit of cost and safety for therapeutic use. Methods We used two late-generation HIV-based lentiviral vector systems (pHR-SIN-cppT SGW and pRRLSIN.cPPT.PGK.WPRE) encoding LacZ/GFP reporter genes to transduce adult and fetal human hepatocytes in vitro + /, growth factors, hepatocyte growth factor (HGF) and epidermal growth factor (EGF). Green fluorescent protein (GFP) expression was observed microscopically, and quantified by fluorescence spectrometry for protein expression, fluorescence-activated cell sorting (FACS) analysis to identify the proportion of cells expressing GFP, and real-time quantitative polymerase chain reaction (PCR) for number of integrations. Results Gene expression following lentiviral transduction of human liver cells in vitro was markedly enhanced by the growth factors HGF and EGF. In adult cells growth factors led to a greater proportion of cells expressing more GFP per cell, from more integration events. In human fetal cells, the proportion of transduced hepatocytes remained identical, but cells expressed more GFP protein. Conclusions This has implications for the design of regimes for liver cell gene therapy, allowing marked reduction of MOIs, and reducing both cost and risk of viral-mediated toxicity. Copyright © 2007 John Wiley & Sons, Ltd. [source] An evaluation of biological and abiotic controls for grapevine powdery mildew.AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2006Abstract Grapevine powdery mildew, caused by the fungus Erysiphe necator, is a major disease affecting grape yield and quality world-wide. In conventionally-managed vineyards, this disease is controlled mainly by regular application of sulfur and synthetic fungicides; and in organic agriculture, by sulfur and canola-based oils. Health and environmental impacts associated with the use of sulfur, development of resistance to certain synthetic fungicides, and demand for residue-free grapes, all point to a need for effective alternatives to sulfur and synthetic chemicals. Accordingly, seven greenhouse experiments were conducted to evaluate the potential of novel (abiotic) materials, as well as certain biological agents, for controlling powdery mildew. Application of Bacillus subtilis, milk (200 mL/L), whey (30 g/L), canola-based oils (2,4 mL/L) and Ecocarb (potassium bicarbonate, 3 g/L) all reduced the severity of powdery mildew, and in some cases by 96% compared with untreated controls. Such treatments thus offer potential as alternatives to sulfur in organic viticulture if their efficacy can be duplicated under field conditions , the subject of paper 2 in this series (Crisp et al. 2006, Australian Journal of Grape and Wine Research12, pp. 203,211). [source] Mechanisms and management of gingival overgrowth in paediatric transplant recipients: a reviewINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2003D. Chabria Summary. Increasing numbers of children are receiving solid organ transplants namely kidney, liver, heart and lung. Patient survival rates following such transplants are essentially good with much of the success attributable to the development of Cyclosporine A (CyA), an immunosuppressive drug, that minimizes organ rejection. However the gingival overgrowth (GO) associated with the use of CyA is not only disfiguring but in paediatric recipients, may interfere with normal oral development and function. Objective. The aim of this review is to summarize current knowledge concerning the aetiology, pathogenesis and management of gingival overgrowth. Methods. Literature pertaining to gingival overgrowth is reviewed with particular reference to the paediatric population. Emphasis is placed on summarizing the evidence pertaining to the effectiveness of intervention. Conclusion. CyA undoubtedly causes gingival overgrowth, the effects and levels of which appears to be more severe in younger patients. There is conflicting evidence as to the effectiveness of oral hygiene regimes, antibiotics and surgery in reducing overgrowth. The introduction of an alternative immunosuppressive agent (Tacrolimus) offers potential as it does not appear to cause overgrowth, although research to date is limited by the small sample size of many of the studies. This is an area in which multicentre studies would be of great value. [source] Toll-like receptors and their role in gastrointestinal diseaseJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2009Adam G Testro Abstract The innate immune response to invading pathogens is centred upon a family of non-clonal, germline-encoded pattern recognition receptors (PRRs), the Toll-like receptors (TLRs). These provide specificity for a vast range of microbial pathogens, and offer an immediate anti-microbial response system. Thirteen mammalian TLRs have been described; 10 are expressed in humans, each responsible for the recognition of distinct, invariant microbial structures originating from bacteria, viruses, fungi and protozoa. The two most thoroughly studied are TLR4 and TLR2, the PRRs for Gram-negative and Gram-positive bacterial products, respectively. TLR4 is also the major receptor recognising endogenous ligands released from damaged or dying cells. Activation of a TLR by its relevant ligand rapidly ignites a complex intracellular signaling cascade that ultimately results in upregulation of inflammatory genes and production of proinflammatory cytokines, interferons and recruitment of myeloid cells. It also stimulates expression, upon antigen presenting cells, of co-stimulatory molecules required to induce an adaptive immune response. Whilst a robust TLR response is critical for survival and defence against invading pathogens, inappropriate signaling in response to alterations in the local microflora environment can be detrimental. Such ,unhelpful TLR responses' could form the basis for a large number of gastrointestinal and liver disorders, including inflammatory bowel disease, viral hepatitis, autoimmune liver diseases and hepatic fibrosis. As our understanding of TLRs expands, the pathogenesis of a number of gastrointestinal disorders will be further elucidated, and this offers potential for specific therapies aimed directly at TLR signaling. [source] RAPID AMMONIUM- AND NITRATE-INDUCED PERTURBATIONS TO CHL a FLUORESCENCE IN NITROGEN-STRESSED DUNALIELLA TERTIOLECTA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 2 2003Erica B. Young When NH4+ or NO3, was supplied to NO3, -stressed cells of the microalga Dunaliella tertiolecta Butcher, immediate transient changes in chl a fluorescence were observed over several minutes that were not seen in N-replete cells. These changes were predominantly due to nonphotochemical fluorescence quenching. Fluorescence changes were accompanied by changes in photosynthetic oxygen evolution, indicating interactions between photosynthesis and N assimilation. The magnitude of the fluorescence change showed a Michaelis-Menten relationship with half-saturation concentration of 0.5 ,M for NO3, and 10 ,M for NH4+. Changes in fluorescence responses were characterized in D. tertiolecta both over 5 days of N starvation and in cells cultured at a range of NO3, -limited growth rates. Variation in responses was more marked in starved than in limited cells. During N starvation, the timing and onset of the fluorescence responses were different for NO3, versus NH4+ and were correlated with changes in maximum N uptake rate during N starvation. In severely N-starved cells, the major fluorescence response to NO3, disappeared, whereas the response to NH4+ persisted. N-starved cells previously grown with NH4+ alone showed fluorescence responses with NH4+ but not NO3, additions. The distinct responses to NO3, and NH4+ may be due to the differences between regulation of the uptake mechanisms for the two N sources during N starvation. This method offers potential for assessing the importance of NO3, or NH4+ as an N source to phytoplankton populations and as a diagnostic tool for N limitation. [source] Synovial ablation in a rabbit rheumatoid arthritis model using photodynamic therapyANZ JOURNAL OF SURGERY, Issue 7 2002Andrew D. Beischer Background: At present there is no ideal minimally invasive method for ablating inflamed synovium in joints that has been unresponsive to optimal medical management in patients with rheumatoid arthritis. The aim of this study was to determine whether photodynamic therapy could be used for this purpose. Methods: In a rabbit knee model of rheumatoid arthritis the pharmacokinetics of the photosensitizer Haematoporphyrin Derivative (HpD) into periarticular tissues and blood was measured following intravenous injection of HpD. The second phase of the study was to determine the histological effect of HpD activation by 63 nm light delivered via an intra-articular optic fibre using a dye pumped KTP-YAG laser. The light dose was varied from 0,200 joule/cm2. Results: Pharmacokinetic studies determined that inflamed synovium rapidly accumulated HpD, with peak levels being reached 12 h following intravenous injection. The ratio of HpD uptake into inflamed synovium versus peri-articular quadriceps muscle was found to be 22.8. Histological examination of the treated knees indicated that selective destruction of inflamed synovium was achieved at light doses 100 joules/cm2 and above. No significant effect was observed on normal intra-articular tissues. Conclusion: We have demonstrated that the first generation photosensitizer HpD selectively accumulates within inflamed synovium. Activation of HpD by intra-articular light administration resulted in selective ablation of the inflamed synovium. These findings indicate that PDT offers potential as a new selective, minimally invasive synovectomy technique. [source] Plant management research: status and what it can offer to address challenges and limitationsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010P.R. CLINGELEFFER Abstract Seasonal fluctuations in yield, grape composition and wine attributes, largely driven by variable climatic conditions, are major challenges for the wine industry aiming to meet consumer expectations for consistent supply, wine style and product quality. This paper will address known causes for this variability and identify management techniques, together with their limitations, that offer potential to modulate these responses. Results will be presented from research studies, conducted over a number of seasons, which link vineyard management practices with fruit composition and wine assessments. They show that there is potential to develop integrated systems to stabilise yield, fruit composition and wine quality attributes across seasons. These techniques include lighter pruning, deficit irrigation techniques and adoption of low-moderate vigour rootstocks which lead to reduced shoot vigour and the development of open canopies and small bunches with small berries, with enhanced colour, phenolics and sensory appeal; application of mechanical and chemical crop thinning techniques for yield stabilisation and promotion of early ripeness, colour and flavour development. However, the results also show that variability between seasons in many cases is much larger than can be achieved by modifying management practices. Hence, opportunities to use management practices to completely reduce the seasonal variability, particularly with respect to grape composition and wine attributes, factors largely affected by climatic conditions during berry development, may be limited. There exists significant potential in the longer term to use new varieties and rootstocks better adapted to variable and changing climatic conditions. It can be concluded that vineyard practices can be modified to stabilise yield, grape composition and wine attributes to varying degrees and hence, minimise the impact of variability in climatic conditions from season to season. In the longer term, the adoption of new varieties together with new rootstocks adapted to higher temperatures and limited water supply will assist the wine industry to cope with impacts of climate variability and change and address ever changing consumer expectations. A total systems approach to vineyard management offers potential to modulate seasonal fluctuations in yield, grape composition and wine quality attributes with significant benefit for an industry. [source] | |||||||||||||