Determination of Linear, Nonlinear, and the Optical Limiting Properties of Sudan Brown RR in a Solid Film and Solution

The casting technique is employed to prepare the film from a mixture of sudan brown RR (SBRR) dye and poly methyl methacrylate (PMMA). The surface profile of this film is identified using a scanning probe microscope and image J software. The linear optical (LO) properties of the solid film were studied. The nonlinear optical (NLO) properties of SBRR/PMMA film and sudan brown (RR) solution in dimethylformamide (DMF) as a solvent are evaluated using two methods including diffraction ring patterns and Z-scan. The optical limiting (OLg) property for the SBRR/PMMA film and SBRR solution was extensively investigated. The values of nonlinear refractive index (NRI) and threshold limiting (TH) of the solid film and dye solution were compared.

Does protracted radon exposure play a role in the development of dementia?

Radon is a ubiquitous radioactive gas that decays into a series of solid radioactive decay products. Radon, and its decay products, enter the human body primarily through inhalation and can be delivered to various tissues including the brain through systemic circulation. It can also reach the brain by neuronal pathways via the olfactory system. While ionizing radiation has been suggested as a risk factor of dementia for decades, studies exploring the possible role of radon exposure in the development of Alzheimer's Diseases (AD) and other dementias are sparse. We systematically reviewed the literature and found several lines of evidence suggesting that radon decay products (RDPs) disproportionally deposit in the brain of AD patients with selective accumulation within the protein fractions. Ecologic study findings also indicate a significant positive correlation between geographic-level radon distribution and AD mortality in the US. Additionally, pathologic studies of radon shed light on the potential pathways of radon decay product induced proinflammation and oxidative stress that may result in the development of dementia. In summary, there are plausible underlying biological mechanisms linking radon exposure to the risk of dementia. Since randomized clinical trials on radon exposure are not feasible, well-designed individual-level epidemiologic studies are urgently needed to elucidate the possible association between radon (i.e., RDPs) exposure and the onset of dementia.