Association of COVID-19 with obesity Association of COVID-19 with obesity

COVID-19 is a disease that cause respiratory illness due to novel corona virus. It was reported to WHO on December 31,2019 for the first time. The outbreak of this disease started from Wuhan city, China. Now COVID-19 pandemic is spreading worldwide mostly in Europe and North America, these regions have high prevalence of obesity. In the pathogenesis of COVID-19 disease, obesity assumes a significant job. Theinsusceptible framework, which is official in the pathogenesis of COVID19, assumes asignificant job in weight instigated fat tissue aggravation. In the fat tissue the irritationbrings about metabolic brokenness conceivably prompting dyslipidemia, type 2diabetes mellitus, insulin obstruction, hypertension and cardiovascular sickness. Obesity has been expanded the vulnerability to contaminations. In this pandemic, a large number of obese individual with Covid-19 are reported. Infection rate in obese is greater due to poor immunity, comorbidity and inadequate nutritional needs. Statistical analysis showed that about 41.7% patients reported in New York city were obese. Whereas 40% obese have been reported in United State of America with Covid-19. A report from UK indicated that 38% obese were admitted in ICU with Covid-19. According to Chinese researchers, obese individuals are 3-timesmore prone toward the development of Covid-19. So recent analysis indicated that obesity is the major risk factor of Covid-19. In COVID-19, overweight and obese patients have high danger of metabolic difficultiesand eternal infections that stoutness works. More nutrition care is required for such patients. As nutrition is a key factor for keeping up human wellbeing, for example, denseimpervious framework and satisfactory admission of supplements and dietaryenhancements. Tolerant with COVID-19 create contamination from slight to seriousindications bound to the dietary status. Consequently, assessing wholesome status ofindividuals with contamination turns out to be increasingly significant. Through dietaryhelp, we can bring down the danger of oxidative pressure, infection contamination andexpands invulnerability framework among obese people especially.

Design and Analysis of Metasurfaces for Polarization Conversion of Electromagnetic Waves

Control and manipulation of polarization state of electromagnetic waves has always been of interest in the scientific community due to its fundamental role in wide range of applications including contrast imaging microscopy, optical sensing, molecular biotechnology and optical and microwave communication. Although, conventional techniques are applied for polarization control using natural materials such as optical activity of crystals, Faraday-effect and solutions of chiral molecules such as sugar. However, such methods generally result in bulky volumes, narrow bandwidth and incidence angle dependent response which greatly limit their use for many practical applications. Therefore, scientists have explored the use of artificial structures in the form of ultra-thin metasurfaces to achieve miniaturized polarization control devices with wide bandwidth and angularly stable response. However, most of these designs achieve polarization conversion for normal incidence only, which practically becomes prohibitive, as incoming waves can have arbitrary incidence angles. Thus, metasurfaces with stable response for arbitrary incidence angles are highly desirable. In this perspective, there are two main objectives of this research thesis: firstly, to realize wideband metasurfaces achieving polarization conversion both for normal as well oblique incidence and secondly, to design metasurfaces which can achieve multiple functionalities through a single structure. The first three metasurface designs presented in Section I achieve angularly stable (maximum up to 60o) wideband cross-polarization conversion in reflection mode. The cross-polarization conversion is achieved through anisotropy of the unit cell while the bandwidth is extended through multiple plasmonic resonances. Multifunctional metasurfaces are presented in Section II. These metasurfaces are extremely desirable in practical applications as they can replace multiple optical components, thus miniaturizing size and reducing the cost of the overall system. The first of the multifunctional metasurfaces presented in this thesis, not only transforms linear and circular polarization to their corresponding cross polarization, but also achieves linear-to-circular and circular-to-linear polarization conversion in different frequency regimes.Thus, it exhibits both half- and quarter-wave plate operations in different frequency bands using an ultra-thin bilayer anisotropic metasurface. The final design presented in this thesis is based on a flexible single layer anisotropic metasurface manifesting both quarter-wave plate and half-mirror (1:1 beam splitter) operation.