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Presently, the whole world is suffering from the Covid-19 pandemic. In this harmful situation, using information and Internet technology is mandatory for the government and medical practitioners. After the lockdown, the government needs to take important decisions to allow passengers to travel through air, rail, and land. In the present situation, people need to get a medical report from the hospitals to travel through various modes of transport. In this regard, the Covid-19 history of the passengers plays an important role in issuing tickets to the passengers. Hence, in this paper, a novel authentication method using InterPlanetary File System (IPFS) is suggested to retrieve the Covid-19 history of all passengers to determine whether to issue tickets and allow people to travel through various modes of transport. The government can share the Covid-19 status of passengers with the ticket issuing authority. The medical practitioners can share medical reports and medical images of such people for telediagnosis. To provide security, a novel privacy-preserving storage and sharing of Covid-19 records using secure authentication and image cryptosystem are proposed using chaos, cryptographic hash (SHA-256), Paillier cryptosystem, and IPFS. Security analysis shows that the system can withstand various kinds of attacks.
RESUMO
AIM: The aim of this study is to evaluate, the influence of four types of sterilization/disinfection procedures (autoclave, hot air oven, glutaraldehyde, and ultraviolet [UV] light) on the tensile strength and surface topography of three orthodontic wires (stainless steel (SS), titanium - molybdenum alloy [TMA], and cobalt chromium (CoCr)). MATERIALS AND METHODS: Sample comprised of three types of 8 inches straight length segments of orthodontic wires. They were divided into three groups according to wire composition comprising of 50 samples each. Totally 50 samples of each group were then equally divided into five subgroups according to sterilization method. After sterilization and disinfection of the experimental group, surface topography was examined with scanning electron microscope (SEM) and tensile strength was tested using universal testing machine. RESULT: The results of this study show that the mean ultimate tensile strength (UTS) of SS wire after four sterilization procedures were similar to the control group (1845.815 ± 142.29 MPa). The mean UTS of TMA wire increases after four sterilization procedures when compared with the control group (874.107 ± 275.939 MPa). The mean UTS of CoCr wire remains same after UV light disinfection, but increases after other three sterilization procedures when compared with the control group (1449.759 ± 156.586 MPa). SEM photographs of the present study shows gross increase in pitting roughness of the surface topography of all the three types of wires after four types of sterilization. CONCLUSION: Orthodontists who want to offer maximum safety for their patients can sterilize orthodontic wires before placement, as it does not deteriorate the tensile strength and surface roughness of the alloys.
RESUMO
We prepared stable colloidal suspension graphene in aqueous medium by surface modification of graphene with 4-benzenediazonium sulfonate. The sulfonate group on graphene surface interacts with water, exhibits well dispersibility and which prevents the aggregation even at neutral pH. This dispersion shows stability for three months and facile to produce films. Using such a modified graphene dispersion, transparent conductive film (TCF) has been fabricated on glass substrate by spin coating method. At appropriate concentration, the film exhibits an excellent optoelectrical property with resistivity of 1.1 kΩ with the transparency of 89% at the wavelength of 550 nm. Further, we also demonstrated the mechanical, thermal, and optoelectrical properties of prepared films.