The impact of SPARC on age-related cardiac dysfunction and fibrosis in Drosophila

Tissue fibrosis, an accumulation of extracellular matrix proteins such as collagen, accompanies cardiac ageing in humans and this is linked to an increased risk of cardiac failure. The mechanisms driving age-related tissue fibrosis and cardiac dysfunction are unclear, yet clinically important. Drosophila is amenable to the study of cardiac ageing as well as collagen deposition; however it is unclear whether collagen accumulates in the ageing Drosophila heart. This work examined collagen deposition and cardiac function in ageing Drosophila, in the context of reduced expression of collagen-interacting protein SPARC (Secreted Protein Acidic and Rich in Cysteine) an evolutionarily conserved protein linked with fibrosis. Heart function was measured using high frame rate videomicroscopy. Collagen deposition was monitored using a fluorescently-tagged collagen IV reporter (encoded by the Viking gene) and staining of the cardiac collagen, Pericardin. The Drosophila heart accumulated collagen IV and Pericardin as flies aged. Associated with this was a decline in cardiac function. SPARC heterozygous flies lived longer than controls and showed little to no age-related cardiac dysfunction. As flies of both genotypes aged, cardiac levels of collagen IV (Viking) and Pericardin increased similarly. Over-expression of SPARC caused cardiomyopathy and increased Pericardin deposition. The findings demonstrate that, like humans, the Drosophila heart develops a fibrosis-like phenotype as it ages. Although having no gross impact on collagen accumulation, reduced SPARC expression extended Drosophila lifespan and cardiac health span. It is proposed that cardiac fibrosis in humans may develop due to the activation of conserved mechanisms and that SPARC may mediate cardiac ageing by mechanisms more subtle than gross accumulation of collagen

Comparison of Commercial Gecko Food on Growth of Rhacodactylus Geckos

Available food sources can provide a different effect on the growth rates of Rhacodactylus auriculatus. In this study three food sources were compared, Repashy MRP, Pangea super foods, and GeckoPro New Caledonian blend. These are composed of similar nutrients but tend to have some points where they vary. Thirty-six gargoyle geckos were put through a trial over a 14 week period to determine which commercially available food source provides the best nutrients for growth, as measured by weight gain. Three groups of twelve were chosen based on a variety of ages and sizes to be given three different foods for an extended period of time to test food stimulus on growth. While all three foods provided nutrients for growth, Geckos fed Pangea and Repashy had the most significant weight increase, while those fed GeckoPro grew the slowest. A cost analysis compared both individual user usage (small quantities) and bulk usage (for larger facilities). For the individual gecko keeper, GeckoPro provides the most cost effective food source, while for bulk usage Pangea provided the best growth rate for the lowest food cost

Theoretical and computer assisted studies in tectonics, structural geology and isotope dating

Several problems in the fields of tectonics, structural geology and isotopic dating were examined and simplified using computer programs. These problems include the theory of refolding, refold applications to three mining areas, hotspots and their relationship to mantle convection systems and ionium dating of volcanic rocks. In the first study, it was shown that current refold classification schemes are inadequate and so modifications were suggested. Various other aspects of multiple generations of interfering folds were also examined. The ideas of refold theory were then applied to three mining areas, the Chisel Lake Ore Body of Manitoba, the Galena-Roubaix District of South Dakota and Montauban-les-Mines of Quebec. These three studies represent three different techniques of identifying fold generations. The third study of this dissertation involved the examination of hotspots/highspots at various localities of the earth. The distribution was then used to define a polygonal convection system, which is similar to laboratory mantle models. It was also attempted to integrate this model with recent whole mantle convection models to see if the combination was compatible with observed hotspot tracks. The final study involves a review of the deficiencies of the various ionium dating techniques used on volcanic rocks. A new method was presented which is free of these deficiencie

Harmonic analysis of lossy piezoelectric composite transducers using the plane wave expansion method

Periodic composite ultrasonic transducers oer many advantages but the periodic pillar architecture can give rise to unwanted modes of vibration which interfere with the piston like motion of the fundamental thickness mode. In this paper, viscoelastic loss is incorporated into a three dimensional plane wave expansion model (PWE) of these transducers. A comparison with experimental and nite element data is conducted and a design to damp out these lateral modes is investigated. Scaling and regularisation techniques are introduced to the PWE method to reduceill-conditioning in the large matrices which can arise. The identication of the modes of vibration is aided by examining proles of the displacements, electrical potentialand Poynting vector. The dispersive behaviour of a 2-2 composite transducer with high shear attenuation in the passive phase is examined. The model shows thatthe use of a high shear attenuation ller material improves the frequency band gap surrounding the fundamental thickness mode

Mean proton and alpha-particle reduced widths of the Porter-Thomas distribution and astrophysical applications

The Porter-Thomas distribution is a key prediction of the Gaussian orthogonal ensemble in random matrix theory. It is routinely used to provide a measure for the number of levels that are missing in a given resonance analysis. The Porter-Thomas distribution is also of crucial importance for estimates of thermonuclear reaction rates where the contributions of certain unobserved resonances to the total reaction rate need to be taken into account. In order to estimate such contributions by randomly sampling over the Porter-Thomas distribution, the mean value of the reduced width must be known. We present mean reduced width values for protons and α particles of compound nuclei in the A = 28–67 mass range. The values are extracted from charged-particle elastic scattering and reaction data that weremeasured at the riangle Universities Nuclear Laboratory over several decades. Our new values differ significantly from those previously reported that were based on a preliminary analysis of a smaller data set. As an example for the application of our results, we present new thermonuclear rates for the 40Ca(α,γ)44Ti reaction, which is important for 44Ti production in core-collapse supernovae, and compare with previously reported results.Peer ReviewedPostprint (published version

British Policy in the South China Sea Area With Special Reference to Sarawak, Brunei and North Borneo 1860-1888.

By 1888 Britain had secured control over the territories on the northwest coast of Borneo and commanded the eastern part of the South China Sea. This may be viewed as the culmination of a fifty year policy of involvement in the area. During the 1840's and 1850's that policy was hesitant and faltering. But after 1860 it became a definite movement toward domination of the route between Singapore and Hong Kong. Two basic factors of British Far Eastern policy were involved. One was the need to maintain and protect the trade route to China. The other factor was the evolution of an imperial policy - the change-over from primarily a commercially based to a politically based policy. The change took place during the quarter of a century following 1860. British activity was motivated more and more by the idea that another power might acquire a territorial footing in northwest Borneo and threaten the trade routes. During the 1860's Britain granted naval protection to Sarawak. It was then but a step to proclaiming a sphere of influence over the whole coast. These moves were as much a reaction to the French presence in Cochin China as they were a reflection of the new imperialist feeling arising in Britain. The suspicion of German intentions in the area moved Britain to strengthen her position. She sponsored the state of North Borneo under rule by a chartered company. By a protocol with Germany and Spain she defined her sphere in Borneo. Finally Britain granted protectorates over Sarawak, Brunei and North Borneo. The purpose of this thesis is to study Britain's position in Borneo from 1860 to 1888 and to show how it reflected the development of policy in London

Repeated supra-maximal sprint cycling with and without sodium bicarbonate supplementation induces endothelial microparticle release

Under normal homeostatic conditions, the endothelium releases microparticles (MP), which are known to increase under stressful conditions and in disease states. CD105 (endoglin) and CD106 (vascular cell adhesion molecule-1) are expressed on the surface of endothelial cells and increased expression in response to stress may be observed. A randomised-controlled double-blinded study aimed to examine the use of endothelial microparticles as a marker for the state of one’s endothelium, as well as whether maintaining acid-base homeostasis affects the release of these MP. This study tested seven healthy male volunteers, who completed a strenuous cycling protocol, with venous blood analysed for CD105+ and CD106+ MP by flow cytometry at regular intervals. Prior to each trial participants consumed either 0.3 g·kg-1 body mass of sodium bicarbonate (NaHCO3), or 0.045 g·kg-1 body mass of sodium chloride (NaCl). A significant rise in endothelial CD105+MP and CD106+MP (p < 0.05) was observed at 90 minutes post exercise. A significant trend was shown for these MP to return to resting levels 180 minutes post exercise in both groups. No significance was found between experimental groups, suggesting that maintaining acid-base variables closer to basal levels has little effect upon the endothelial stress response for this particular exercise mode. In conclusion, strenuous exercise is accompanied by MP release and the endothelium is able to rapidly recover in healthy individuals, whilst maintaining acid-base homeostasis does not attenuate the MP release from the endothelium after exercise

Implications of a pre-exercise alkalosis-mediated attenuation of HSP72 on its response to a subsequent bout of exercise

The aim of this study was to investigate if a pre-exercise alkalosis-mediated attenuation of HSP72 had any effect on the response of the same stress protein after a subsequent exercise. Seven physically active males [25.0 ± 6.5 years, 182.1 ± 6.0 cm, 74.0 ± 8.3 kg, peak aerobic power (PPO) 316 ± 46 W] performed a repeated sprint exercise (EXB1) following a dose of 0.3 g kg⁻¹ body mass of sodium bicarbonate (BICARB), or a placebo of 0.045 g kg⁻¹ body mass of sodium chloride (PLAC). Participants then completed a 90-min intermittent cycling protocol (EXB2). Monocyte expressed HSP72 was significantly attenuated after EXB1 in BICARB compared to PLAC, however, there was no difference in the HSP72 response to the subsequent EXB2 between conditions. Furthermore there was no difference between conditions for measures of oxidative stress (protein carbonyl and HSP32). These findings confirm the sensitivity of the HSP72 response to exercise-induced changes in acid–base status in vivo, but suggest that the attenuated response has little effect upon subsequent stress in the same day

Consumer Response to Outsourced 1-800 calls: It’s the Solution Not the Country

The growth of call center outsourcing and its emergence as a political and economic issue may have obscured some very important business and consumer issues. It is believed by many that consumers cannot be satisfied when calls are outsourced (offshored to India for example). The purpose of this study is to understand the relationship between where a call is answered and what happened on that call. In this study call outsourcing is placed within the well understood area of country-oforigin effects. Two experiments were completed in which outsourced country was manipulated with call outcome (resolution or no resolution). The findings showed that with no other information presented consumers do have a negative bias (lower expectations of satisfaction) against calls answered offshore. Yet when offshore outsourcing is presented in the context of what we know is important to callers to call centers (speed of answer and resolution) there is no effect of offshore calls