Processing vein quartz in Badulla area to suit manufacturing chemically reinforced glasses

Chemically reinforced glass, commercially known as tempered glass has a high global demand with the rapid increase in the usage of touch-screen type mobile phones and tablets. To maintain a high quality and to enable improvements of these devices the resolution, clarity and durability of tempered glass has to be improved and therefore, the selection of quality raw silica for tempered glass has become critical. Sri Lanka is one of the main exporters of silica to the world market and currently, Sri Lankan supplies mainly consist of crushed and powdered bulk unprocessed raw material. In this background, it would be prudent to export semiprocessed quartz as raw material for chemically reinforced glass. The requirements for chemically reinforced glass is a minimum value of 99.8 %, SiO2 and the maximum impurity levels of 9 ppm of Fe2O3 and 350 ppm of Al2O3 with the size requirement being 75-300 microns. In this study, sources for the production of raw material for the production of chemically reinforced glass was investigated using various types of vein quartz originating from quarries situated at Badulla in Sri Lanka. Milky, Smokey, Transparent, Rose, Mica associated and Feldspar associated quartz obtained from 7 quarries were investigated. Samples were analyzed using Atomic Absorption Spectrophotometer (AAS) and Inductively Coupled Plasma (ICP) techniques for trace elements. Results of the chemical analysis showed a markedly low iron content with less than 15 ppm in transparent quartz, less than 25 ppm in milky quartz, less than 30 ppm in smokey quartz, less than 35 ppm in rose quartz, less than 30 ppm in mica associated quartz and less than 300 ppm in feldspar associated quartz. More than 700ppm of Al2O3 content was observed in feldspar associated quartz. Cr content in rose quartz was more than 700 ppb and more than 800 ppb in mica associated quartz. Smokey quartz showed a high Ni and Al2O3 contents. Milky and transparent quartz in the observed quarries showed the lowest trace element contents and their natural quality close to the requirements of chemically reinforced glass and SiO2 levels are higher than 99.8%. Further results obtained using an industrial scale pilot plant show a significant reduction of Fe content, less than 5 ppm occurring in milky quartz with size reduction carried out followed by magnetic separation and removal of fraction less than 75 micron. Processed transparent quartz and milky quartz in Badulla area can directly be exported as raw material for chemically reinforced glass

Chronic Exposure to Combined Carcinogens Enhances Breast Cell Carcinogenesis with Mesenchymal and Stem-Like Cell Properties

Breast cancer is the most common type of cancer affecting women in North America and Europe. More than 85% of breast cancers are sporadic and attributable to long-term exposure to small quantities of multiple carcinogens. To understand how multiple carcinogens act together to induce cellular carcinogenesis, we studied the activity of environmental carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P), and dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) using our breast cell carcinogenesis model. Our study revealed, for the first time, that combined NNK and B[a]P enhanced breast cell carcinogenesis chronically induced by PhIP in both non-cancerous and cancerous breast cells. Co-exposure was more potent than sequential exposure to combined NNK and B[a]P followed by PhIP in inducing carcinogenesis. Initiation of carcinogenesis was measured by transient endpoints induced in a single exposure, while progression of carcinogenesis was measured by acquisition of constitutive endpoints in cumulative exposures. Transient endpoints included DNA damage, Ras-Erk-Nox pathway activation, reactive oxygen species elevation, and increased cellular proliferation. Constitutive endpoints included various cancer-associated properties and signaling modulators, as well as enrichment of cancer stem-like cell population and activation of the epithelial-to-mesenchymal transition program. Using transient and constitutive endpoints as targets, we detected that a combination of the green tea catechins ECG and EGCG, at non-cytotoxic levels, was more effective than individual agents in intervention of cellular carcinogenesis induced by combined NNK, B[a]P, and PhIP. Thus, use of combined ECG and EGCG should be seriously considered for early intervention of breast cell carcinogenesis associated with long-term exposure to environmental and dietary carcinogens

Psychology of Resilience

Research in the area of psychological resilience has gained much popularity since the birth of positive psychology movement in the late 1990s. This chapter attempts to summarize the progress of research conducted in the area. It begins by tracing the emergence of the concept with special focus on its development since the positive psychology movement. The concepts of vulnerability, risk and protective factors, as well as major theoretical frameworks proposed by resilience researchers in attempting to understand resilience, are discussed. Over the years, resilience researchers have faced several conceptual and methodological constraints in studying the phenomena. These issues have been highlighted in order to provide further clarification on the topic. An outline of recent researches in the area with an emphasis on the contributions made by Indian researchers is presented. Finally, applications of findings along with directions for future research have been discussed