Animal Models of Diabetic Retinopathy (Part 2)

Diabetic retinopathy (DR) is one of the leading causes of preventable vision impairment and blindness in the working-age population worldwide. Numerous animal models have been developed for therapeutic drug screening and to further increase our understanding of the molecular and cellular pathological processes involved in DR. Following our discussion of mouse models in “Animal Models of Diabetic Retinopathy Part 1,” we describe the cellular, molecular, and morphological features of both rodent and nonrodent models of DR and their respective advantages and limitations in this chapter. To date, no animal model can holistically reproduce the pathological progression of human DR; most only display early or advanced lesions of DR. However, a thorough understanding of genotypic and phenotypic expressions of existing models will facilitate researchers’ selection of the appropriate model to simulate their desired clinical scenarios

Security Issues in a SOA-based Provenance System

Recent work has begun exploring the characterization and utilization of provenance in systems based on the Service Oriented Architecture (such as Web Services and Grid based environments). One of the salient issues related to provenance use within any given system is its security. Provenance presents some unique security requirements of its own, which are additionally dependent on the architectural and environmental context that a provenance system operates in. We discuss the security considerations pertaining to a Service Oriented Architecture based provenance system. Concurrently, we outline possible approaches to address them

Dynamical and Stationary Properties of On-line Learning from Finite Training Sets

The dynamical and stationary properties of on-line learning from finite training sets are analysed using the cavity method. For large input dimensions, we derive equations for the macroscopic parameters, namely, the student-teacher correlation, the student-student autocorrelation and the learning force uctuation. This enables us to provide analytical solutions to Adaline learning as a benchmark. Theoretical predictions of training errors in transient and stationary states are obtained by a Monte Carlo sampling procedure. Generalization and training errors are found to agree with simulations. The physical origin of the critical learning rate is presented. Comparison with batch learning is discussed throughout the paper.Comment: 30 pages, 4 figure

Comparative Laboratory Leaching Test Methods to Study Post-Treatment Storage Period Impacts on CCA Leachability and Fixation in Treated Kempas (Koompassia malaccensis) Heartwood

Three laboratory leaching test methods were compared to determine the effects of different post-treatment storage fixation periods on leachability/fixation of CCA components from treated kempas (Koompassia malaccensis) permeable heartwood. End-sealed test wood blocks of permeable were treated with CCA to target retention of 5.6 kg/m3, immediately stored to fix at ambient conditions for 0 and 48 hours, 1, 2 and 4 weeks, followed by a 2 weeks leaching test comparing 3 leaching tests: the methods of EN84 (consisting of initial vacuum impregnation of wood in water), EN84-1 (replacing initial vacuum impregnation with initial immersion of wood in water) and a new, and least severe, test EN84-2 (daily routine of soaking wood for 5 hours in water followed by drip drying for 19 hours). Leachates harvested from these leaching tests were analysed for cumulative leaching losses of copper (Cu), chromium (Cr) and arsenic (As) that occurred over the 2 weeks leaching period. Overall, leached CCA elements ranged from 0.48 – 4.02μg/ml Cu, 0.61 – 5.76 μg/ml Cr and 0.46 – 4.02 μg/ml As. There were significant variations in leaching losses (P<0.05) between unfixed and stored fixed blocks among the 3 laboratory leaching test methods. Significant variations of Cu, Cr and As levels existed between the least severe method and the other two methods that used prolonged immersion of wood in water. However, there were no significant differences in CCA leaching losses between EN84 method and the EN84-1 method, while the merits of the least severe leaching regime as indicators of realistic CCA leaching of “fixed” treated wood aboveground outdoors are discussed

Modulation of Ca2+-dependent anion secretion by protein kinase C in normal and cystic fibrosis pancreatic duct cells

AbstractThe study investigated the role of protein kinase C (PKC) in the modulation of agonist-induced Ca2+-dependent anion secretion by pancreatic duct cells. The short-circuit current (ISC) technique was used to examine the effect of PKC activation and inhibition on subsequent ATP, angiotensin II and ionomycin-activated anion secretion by normal (CAPAN-1) and cystic fibrosis (CFPAC-1) pancreatic duct cells. The ISC responses induced by the Ca2+-mobilizing agents, which had been previously shown to be attributed to anion secretion, were enhanced in both CAPAN-1 and CFPAC-1 cells by PKC inhibitors, staurosporine, calphostin C or chelerythrine. On the contrary, a PKC activator, phorbol 12-myristate 13-acetate (PMA), was found to suppress the agonist-induced ISC in CFPAC-1 cells and the ionomycin-induced ISC in CAPAN-1 cells. An inactive form of PMA, 4αd-phorbol 12,13-didecanote (4αD), was found to exert insignificant effect on the agonist-induced ISC, indicating a specific effect of PMA. Our data suggest a role of PKC in modulating agonist-induced Ca2+-dependent anion secretion by pancreatic duct cells. Therapeutic strategy to augment Ca2+-activated anion secretion by cystic fibrosis pancreatic duct cells may be achieved by inhibition or down-regulation of PKC