Background: Having a healthy behavior and physiology is impossible without normal sleep pattern. Between the ages 18 and 25, people are prone to sleep disturbances. College life, which mostly occurs during this ages also affects the sleep pattern.Methods: This is a descriptive cross sectional study conducted among MBBS students of Stanley Medical College during august to September 2009. About 300 students were randomly selected using table of random numbers. Data was collected using a questionnaire and entered in SPSS version 16 software. Analysis was done using chi-square test. P value of less than 0.05 was taken as statistically significant.Results: Prevalence of insomnia is found to be 37% and is significantly higher among males. Disturbed sleep is higher among males.Conclusions: Prevalence of insomnia is 37% and is significantly higher among males. About 26.3% of the participants had disturbed sleep.

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Semiconductors with wide bandgap are crucial for optoelectronic devices and energy applications owing to their electron confinement, high optical transparency and tunable electrical conductivity. Therefore, in this study, the quantum confinement effect of the energy bandgap of chalcogenide semiconductor nanocrystals such as ZnS, ZnSe, ZnTe, SnS, SnSe and SnTe are studied based on the Brus model using the effective mass approximation, the hyperbolic band model and the cohesive energy model. The obtained results indicate that the value of energy bandgap differs from the bulk crystals related to the quantum confinement effect. These verdicts confirm the quantum confinement effects of materials and their potential applications in optoelectronic devices. Theoretical findings are compared with its valid experimental data.