Can Rapid Antigen Tests Lessen the Burden on Testing Laboratories? An Evaluation of the Testing Methods during the COVID-19 Pandemic

Introduction: Timely diagnosis and isolation of cases is of paramount importance to contain the spread of a pandemic. The Coronavirus Disease-2019 (COVID-19) has emerged as a major health problem that needs concerted efforts for mitigation and control. Real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR), the gold-standard diagnostic modality, has high cost and can be performed in special laboratories. Rapid Antigen Tests (RAT) has been developed to serve as an alternative and is recommended to use at point-of-care testing. Aim: To compare the case detection rate of RAT and RT-PCR and the possible role they may play in the pandemic mitigation efforts. Materials and Methods: In this retrospective study, all the samples collected during a nine-months period were analysed. Depending upon the criteria, either a RAT or RT- PCR was done on the samples. Data was analysed using descriptive statistics (frequencies, mean, standard deviation, and percentages). Results: A total of 8,29,745 samples were tested during the study period among which number of positive samples was 19,414 giving an overall positivity rate of 2.34% (0.20% to 12.58%). RAT positivity was 1.58% while RT-PCR gave a positivity of 4.26. Total number of positive cases identified by RAT and RT-PCR were 9,382 and 10,032, respectively. Conclusions: RAT is a low-cost alternative to the expensive RT-PCR with the added advantage of giving accurate and timely results. This can be a game changer especially in low-resource settings, which have witnessed a increase in the spread of COVID-19 during the latter part of the pandemic

Effectiveness of thermal radiations and homogeneous–heterogeneous reactions in Maxwell flow field across a rotating cylinder

This paper investigates the impact of cubic autocatalysis on energy transport in Maxwell fluid flow induced into a rotating cylinder inspired by a solar radiative surface. The homogeneous-reaction is assumed to be furnished by the kinetics of isothermal cubic autocatalytic and the heterogeneous reaction by kinetics of first order. To prevent induced axial secondary flow, the cylinder's rotation is maintained at a constant rate. The characteristics of thermal radiation are also investigated to regulate the pace of heat transmission. A magnetic beam is projected in the upward radial direction to control the fluid momentum. A suitable flow ansatz is used to convert the entire physical problem of thermal energy transmission and fluid flow from partial differential equations (PDEs) to nonlinear ordinary differential equations (ODEs). Results obtained numerically with the bvp4c approach are presented graphically and explained physically. It is observed that by flourishing the Reynolds parameter, the penetration depth decreases. Further, when the thermal relaxation period increases, the temperature field degrades. Moreover, when the homogeneous–heterogeneous reaction's strength is increased, a reduction in fluid concentration is shown

Darcy flow of convective and radiative Maxwell nanofluid over a porous disk with the influence of activation energy

This study reveals an incompressible steady Darcy flow of Maxwell nanofluid by a porous disk with the impact of activation energy. The liquid flow is due to a stretchable rotating disk. The heat equation also includes the impact of heat source/sink and radiation for the purpose of heat transportation. The von Karman transformations are utilized to gain the dimensionless form of ordinary differential equations (ODEs). The solutions are visualised in the form of graphical results using bvp 4c method in Matlab software. The ranges of the associated physical parameters as, 0.0≤β≤0.9, 0.0≤M≤0.9, 0.0≤λ≤1.5, 0.1≤R≤0.9, −0.2≤s≤1.3, 0.3≤Bi≤0.6, 0.0≤γ≤0.15, 0.1≤Nt≤2.0, 0.2≤Nb≤0.8, 0.0≤Rd≤0.3, 0.0≤σ≤1.5, and 0.0≤E≤0.9 are provided for the graphical solutions developed for the problem. The data of Nussetl and Sherwood numbers are presented here with regard to various physical parameters. According to the numerical results, increasing the Deborah number has a trend to decrease the radial curves. Moreover, the temperature distribution is increased considerably for rising the radiation parameter and the higher rate of the rotation parameter shows a weaker concentration trend. To validate the numerical approach, an excellent comparison is established using a tabular description. To sum up, the current study effectively fills a gap in the antecedent literature

A theoretical analysis of the ternary hybrid nanofluid flows over a non-isothermal and non-isosolutal multiple geometries

The current problem is concerned with the study of magnetohydrodynamic ternary hybrid nanofluid flow over two distinct geometries i.e., cone and wedge. The ternary hybrid nanoliquid with MHD has a lot of engineering and industrial applications. In polymer data processing, cone and wedge geometries are frequently utilized. Therefore, the present problem is designed to the flow of ternary hybrid nanoliquid over multiple geometries. Hybrid nanoliquids performed well in the heat transport rate as compared to the nanoliquid and conventional liquid. Here in this study, the idea of ternary hybrid nanoliquid is introduced to improve the energy and mass transmissions which show more satisfactory results in the thermal and mass transmission performance. The impacts of chemical reaction and thermal radiation are also executed in this model. The formulation of the present study is performed in the form of PDEs which are then transformed into the ODEs by using suitable similarity transformations. The homotopic analysis scheme is implemented for the semi-analytical solution of the existing model. Some major results that materialize from the present simplification are that; the tri-hybrid nanoliquid velocity is greater for the rising nanoparticles volume fractions. The enlargement in radiation parameter enlarged the tri-hybrid nanoliquid thermal profile. The mass transfer rate of the ternary hybrid nanoliquid is lesser for the Schmidt number and chemical reaction. Intensification in nanoparticles volume fractions and radiation parameter has increased the ternary hybrid nanofluid heat rate transfer for both cone and wedge geometries

Mechanical characteristics of MHD of the non-Newtonian magnetohydrodynamic Maxwell fluid flow past a bi-directional convectively heated surface with mass flux conditions

In engineering and manufacturing industries, stretching flow phenomena have numerous real-world implementations. Real-world applications related to stretched flow models are metalworking, crystal growth processes, cooling of fibers, and plastics sheets. Therefore, in this work, the mechanical characteristics of the magnetohydrodynamics of the non-Newtonian Maxwell nanofluid flow through a bi-directional linearly stretching surface are explored. Brownian motion, thermophoresis, and chemical reaction impacts are considered in this analysis. Additionally, thermal convective and mass flux conditions are taken into consideration. The mathematical framework of the existing problem is constructed on highly non-linear partial differential equations (PDEs). Suitable similarity transformations are used for the conversion of partial differential equations into ordinary differential equations (ODEs). The flow problem is tackled with the homotopy analysis method, which is capable of solving higher-order non-linear differential equations. Different flow profiles against various flow parameters are discussed physically. Heat and mass transference mechanisms for distinct flow factors are analyzed in a tabular form. The outcomes showed that both primary and secondary velocities are the declining functions of magnetic and Maxwell fluid parameters. The heat transfer rate rises with the cumulative values of the Brownian motion and thermal Biot number. In addition, the mass transfer rate decreases with the rising Schmidt number, Brownian motion parameter, and chemical reaction parameter, while it increases with the augmenting thermophoresis parameter. It has been highlighted that streamlines in the current work for Maxwell and Newtonian models are in fact different from one another