A Cross-Sectional Survey of Knowledge, Attitude, and Practices of University Students in Pakistan Regarding COVID-19.

The COVID-19 pandemic is striking the world with serious public health and socioeconomic complications. The pandemic has influenced all forms of daily life, including educational institutions. Therefore, this cross-sectional survey was conducted to understand knowledge, attitudes, and practices related to COVID-19 among the students of the University of Veterinary and Animal Sciences, Lahore. The data was collected using an online self-directed questionnaire. The survey form includes six items about sociodemographic characteristics, 14 knowledge-based questions, seven questions on attitude, and eight questions on practices. The sample number was calculated using the Raosoft sample size calculator. A total number of 3,854 students, including 1,823 men and 2,031 women, were engaged in this survey, having student representation from all the provinces in the country. The data were analyzed using a chi-square test. A total of 97% of the students knew that the etiological agent of COVID-19 is a virus and that it is a disease of the respiratory system (94%). Many students kept visiting their relatives during the lockdown (45%), and their relatives kept visiting them at home (59%). The responses from the students varied a lot on specific questions about the transmission of the virus. Women tended to have less information regarding precautionary travel measures (p < 0.01), but supplemental knowledge of prevention of disease transmission from positive patients (p < 0.01). Conclusively, the majority of the university students surveyed had imperative knowledge, a good attitude, and active practice in response to the COVID-19 outbreak. Moreover, the KAP scores have varied by demography, gender, and the number of family members. Therefore, continuous awareness of preventative behaviors should be disseminated regularly in emergencies.

Fabrication of buried nanostructures by atomic layer deposition.

We present a method for fabricating buried nanostructures by growing a dielectric cover layer on a corrugated surface profile by atomic layer deposition of TiO2. Selecting appropriate process parameters, the conformal growth of TiO2 results in a smooth, nearly flat-top surface of the structure. Such a hard surface can be easily cleaned without damage, making the nanostructure reusable after contamination. The technique has wide applicability in resonance-domain diffractive optics and in realization of quasi-planar metamaterials. We discuss design issues of such optical elements and demonstrate the method by fabricating narrow-band spectral filters based on the guided-mode resonance effect. These elements have strong potential for, e.g., sensing applications in harsh conditions.

Effect of substrate overetching and heat treatment of titanium oxide waveguide gratings and thin films on their optical properties.

We investigate subwavelength titanium oxide (TiO2) resonance waveguide gratings (RWGs) and TiO2 thin films of thicknesses ~200 nm fabricated by atomic layer deposition (ALD), in both amorphous and crystalline phases on fused silica substrates. The TiO2 RWGs are fabricated by electron beam lithography, reactive ion etching, and ALD. The thin films and RWGs are characterized structurally by x-ray diffraction and scanning electron microscopy. The optical characterization of RWGs and optical constants of TiO2 films are studied by an ellipsometer. RWGs are designed for TE and TM modes in such a way that an overetch effect of the fused silica substrate can be investigated. Various RWG samples are prepared by gradually increasing the overetch depth and subsequently measuring the performance of the RWGs. A close agreement between the calculated and experimentally measured resonance wavelength spectral shifts is obtained; however, the magnitudes of the measured shifts are greater than calculated ones. A parallel study related to the measurement of the refractive indices and remeasuring the optical shifts of RWGs is carried out after a heat treatment of all the samples under study. The RWGs do not reveal significant spectral changes after the heat treatment; this is primarily due to a change in the surface chemistry by the redeposition of the reaction byproducts on the grating lines.