ABSTRACT
The ongoing global outbreak of coronavirus disease has necessitated the use of ultraviolet (UV) disinfection techniques to reduce viral transmission in public places. The previously used UV wavelength is harmful to the human body, the wavelength range from 200 to 235 nm, often referred to as far-UVC light, has attracted attention as a novel disinfection wavelength range that can be used in a safe manner. However, the currently used light sources have practical problems, such as an expensive cost, a low efficiency, and short lifetimes. Therefore, environmentally friendly solid-state light sources with a lower cost, higher efficiency, and longer lifetimes are demanded. Here, an efficient mercury-free far-UVC solid-state light source is presented. This light source demonstrates intense 230 nm emission with a narrow spectral width of 30 nm and a long lifetime of more than 1000 h. These characteristics can be achieved by graphene nanostructure field emitters and wide-bandgap magnesium aluminate phosphors. By using this light source, the efficient disinfection of Escherichia coli is demonstrated. The light sources presented here facilitate future technologies for preventing the spread of infectious diseases in a safe and convenient manner.
ABSTRACT
During the Coronavirus pandemic, the world counted on conventional sanitizing products that involved unsafe toxic chemicals. Ultraviolet Germicidal Irradiation or ultraviolet disinfection is introduced in many sanitizing applications, as it splits the DNA/RNA, forcing microorganisms unable to spread. For that, ultraviolet disinfection technology is presented in this project to replace the old nonenvironmental practices. Far-ultraviolet type C is a small part of the ultraviolet spectrum, with wavelengths from 207 nm to 222 nm proven effective against micrograms. This project aims to apply far-ultraviolet technology to design an easily used, reliable, and optimized system to control and monitor the sanitizing operation. Moreover, this project design combines two different sanitizing modes intended to serve the need of a dental clinic's daily sanitizing technique. The first mode is intended to sanitize the dentist's tools connected to a monitoring system that shows the ultraviolet type C intensity and the received dosage. The second mode is for the surfaces and handlers in the clinic;the sanitizing handheld will be attached to a distance identification system that guides the user to apply the sanitizing operation at the proper distance. Furthermore, this project will determine the disinfection parameters (dosage, intensity, exposure time, wavelength, and distance) according to the used far-ultraviolet source and the prototype design. © 2022 IEEE.
ABSTRACT
From the receptor-binding domain (RBD) of the SARS-CoV-2 virus, which causes coronavirus disease 2019 (COVID-19), a RBD-hFc fusion protein was obtained at the Center of Molecular Immunology (Havana, Cuba). This fusion protein was used in the construction of a diagnostic device for COVID-19 called Ultramicroenzyme-Linked Immunosorbent Assay (UMELISA)-SARS-CoV-2-IgG and it is currently been used in the studies of biological activity of the Cuban vaccine Abdala (CIGB-66). In this work, Circular Dichroism (CD) is used to characterize this protein. Using Far Ultraviolet Circular Dichroism (FAR-UV CD), it was determined that the protein has a secondary structure in the form of a sheet-beta fundamentally. Using this technique, a thermodynamic study was carried out and it was determined that the melting temperature (Tm) of the protein is 71.5 degrees C. Information about the tertiary structure of the protein was obtained using Near Ultraviolet Circular Dichroism (NEAR-UV CD) and Molecular Fluorescence;they indicates that the protein has a three-dimensional folding associated with the aromatic amino acids in its structure, where tryptophan (Trp) is located inside the folded structure of the protein while tyrosine (Tyr) is exposed to the solvent.