Myopia is the most common refractive error worldwide. This cannot be explained by genetic factors alone, therefore, environmental factors may play an important role. Hence, the main objective of this study was to analyse whether outdoor exposure could exert a protective effect against the development of myopia in a cohort of young adults and to investigate ultraviolet autofluorescence (CUVAF), as a biomarker of time spent outdoors. A cross-sectional observational study was carried out using two cohorts. A total of 208 participants were recruited, 156 medical students and 52 environmental science students. The data showed that 66.66% of the medical students were myopic, while 50% of the environmental science students were myopic (p = 0.021). Environmental science students spent significantly more hours per week doing outdoor activities than medical students (p < 0.0001), but there was no significant difference with respect to near work activities between them. In both cohorts, the degree of myopia was inversely associated with CUVAF, and a statistically significant positive correlation was observed between spherical equivalent and CUVAF (Pearson’s r = 0.248). In conclusion, outdoor activities could reduce the onset and progression of myopia not only in children, but also in young adults. In addition, CUVAF represents an objective, non-invasive biomarker of outdoor exposure that is inversely associated with myopia.
Understanding the knowledge of swelling and stability properties of polymeric spheres are essential for improved oil recovery; these properties will allow guaranteeing an efficient block of high permeability channels and large pore throats. These properties of nano/micron-sized polymeric spheres commercially available for improved oil recovery applications were investigated. The polymeric spheres emulsion was characterized by scanning electron microscopy (SEM). Data analysis reveals uniform and spherical structures with an average diameter of 47 AE 4.8 nm. After hydration, polymeric spheres can swell due to water absorption reaching an average particle diameter of 3.3 AE 0.2 μm. The effect of aging time, thermal treatment, the removal of the oil phase, and the dispersing stabilizer on the swelling and stability was studied. It has been found that polymeric spheres structure suffers deterioration with the progressive aging time, temperature increase, and with the removal of the oil phase and dispersing stabilizer. As a result, crosslinked polymer aggregates are formed which subsequently acquiring fibrillar morphologies. Further, this study provides an understanding of the stability and swelling behavior of polymeric microspheres using polydimethylsiloxane microdevices. The results evidenced that the behavior of the polymeric spheres can be beneficial to improve oil recovery.
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