Nanoparticle Notch Filters for Selective Filtering of Blue Light in Contact Lenses

The visible wavelengths are essential to a normal colour vision, however overexposure of high-energy visible (HEV) light may be damaging to both ocular and non-ocular health. Some health concerns associated with HEV light (commonly referred to as blue light) include retinal damage, age-related macular degeneration (AMD) and photophobia in benign essential blepharospasm (BEB) and migraine patients. Certain wavelengths of blue light are essential to regulating bodily functions such as pupillary light reflex, melatonin regulation, and circadian rhythm, therefore completely filtering out these wavelengths may have adverse health effects. Despite its health impact, there is a severe dearth of blue light filtering eyewear that provide adequate protection from harmful blue-light wavelengths while allowing beneficial wavelengths of blue light to be transmitted. Contact lenses are an attractive platform for incorporating blue-light filters. There are currently over 71 million contact lens wearers worldwide, however there are currently no commercially available contact lenses on the market offering both UV and blue light protection. This thesis presents a novel approach to selectively filtering out blue-light wavelengths in contact lenses through the use of plasmonic silver nanoparticles (AgNPs). First, a tunable synthesis process was developed to allow for the production of AgNPs with customizable localized surface plasmon resonance (LSPR) peaks between 400 – 450 nm and full width at half maximum (FWHM) values of less than 45 nm. Next, the blue-light filtering AgNPs were encapsulated with a thick, uniform layer of silica to preserve colloidal and optical stability as well as minimizing leaching of Ag+ ions. Lastly, the silica-coated AgNPs were integrated into commercial etafilcon contact lenses using industry transferrable processes. The NP-integrated lenses demonstrated blue-light filtering capabilities while being transparent in the visible wavelengths. In addition, the NP-integrated lenses demonstrate stability post-autoclaving, UV and natural sunlight exposure, and room temperature storage

Stomach contents of cetaceans incidentally caught along Mangalore and Chennai coasts of India

Abstract The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits

Floating Photocatalysts for Passive Solar Degradation of Naphthenic Acids in Oil Sands Process-Affected Water

Oil sands process-affected water (OSPW), generated from bitumen extraction in the Canadian oil sands, may require treatment to enable safe discharge to receiving watersheds, as dissolved naphthenic acids (NAs) and other acid extractable organics (AEO), identified as the primary toxic components of OSPW, are environmentally persistent and poorly biodegradable. However, conventional advanced oxidation processes (AOPs) are impractically expensive to treat the volumes of OSPW stockpiled in the Athabasca region. Here we prepared floating photocatalysts (FPCs) by immobilizing TiO2 on glass microbubbles, such that the composite particles float at the air-water interface for passive solar photocatalysis. The FPCs were demonstrated to outperform P25 TiO2 nanoparticles in degrading AEO in raw OSPW under natural sunlight and gentle mixing conditions. The FPCs were also found to be recyclable for multiple uses through simple flotation and skimming. This paper thus demonstrates the concept of a fully passive AOP that may be scalable to oil sands water treatment challenges, achieving efficient NA reduction solely through the energy provided by sunlight and natural mixing processes (wind and waves)

Photocatalytic Activity of Hydrogenated TiO₂

Photocatalysis is a promising advanced water treatment technology, and recently the possibility of using hydrogenation to improve the photocatalytic efficiency of titanium dioxide has generated much research interest. Herein we report that the use of high-temperature hydrogenation to prepare black TiO₂ primarily results in the formation of bulk defects in the material without affecting its electronic band structure. The hydrogenated TiO₂ exhibited significantly worse photocatalytic activity under simulated sunlight compared to the unhydrogenated control, and thus we propose that high-temperature hydrogenation can be counterproductive to improving the photocatalytic activity of TiO₂, because of its propensity to form bulk vacancy defects

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Not AvailableAbstract The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits.Not Availabl