Browsing by Author "Gautam, Suman"

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    Estimation of Dynamic and Liquefaction Properties by Shear Wave Velocity
    (Department of Geology, 2009) Gautam, Suman
    The analysis of foundation vibrations and geotechnical earthquake engineering problems in civil engineering requires characterization of dynamic soil properties using geophysical methods. Dynamic structural analysis of the superstructures also requires knowledge of the dynamic response of the soil­structure, which in turn relies on dynamic soil properties. Geophysical methods are often used to characterize the dynamic soil properties of the subsurface. This method requires a borehole through which a sensing probe is lowered at known level. Source near the borehole is generated artificially with the help of wooden plank and hammer. The seismogram obtained from computer aided system is used to determine shear wave velocity and compressive wave velocity which is further used to calculate dynamic parameters such as Poisson’s ratio, dynamic shear modulus, dynamic elastic modulus and predominant period etc. Ground water table is very close to ground surface and the soil is mainly fine to coarse sand with some intermittent layers of cohesive soils meaning that the soil is very liable to liquefaction. Liquefaction resistance is assessed in terms of cyclic stress ratio and in terms of factor of safety both of which show that the liquefaction potential of the site is very high mainly near shallow depth less than 10m.
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    Validation of rapid antigen test as diagnostic tool for detection of SARS-CoV- 2AS compared with real time RT-PCR
    (Department of Biotechnology, 2022) Gautam, Suman
    Introduction: Testing of samples from suspected SARS-COV-2 individuals with rtRT-PCR result leads to delayed in detection of infection. Early recognition of SARS-CoV-2 infection is crucial for both the improvement of turnaround time and limiting the spread of the virus in the Community. Huge number of people affected in pandemic, it is important to use a test that give faster results and can be used on large number of sample. Rapid Antigen Test fulfills both the criteria. AIM: The aim of our study was to evaluate the diagnostic performance of two antigen rapid diagnostic kits (RAT) to diagnose SARS-CoV-2 infection in comparison to rtRT-PCR. So, we evaluated two commercially available antigen kit. Methods: A laboratory based descriptive Crosssectional study was performed in Trishuli Hospital Nuwakot from January 2021 to December 2021. Result: Out of 1295, 472 tested positive in RAT test while 715 tested positive for SARS-CoV-2 RNA genome via rtRT-PCR. Specificity was 98.2% for Panbio and 96.9% for SD Biosensor. Sensitivity for sample with CT ≤ 20 was 93.5% and 94.2% and for sample with CT ≤ 25 was 93.7% and 93.5% and for CT ≤ 30 was 82.9% and 81.4% with p < 0.001 in case of Panbio and SD Biosensor respectively. The overall diagnostic performance of RAT showed 64.2% sensitivity and 97.8% specificity. Agreement with PCR was excellent for high viral load sample CT<20: Panbio, kappa=0.921; SD Biosensor, Kappa= 0.912 and CT value <25: Panbio, Kappa=0.926; SD Biosensor, Kappa=0.906. Significant difference (p value <0.0001) was observed between RAT+ and RAT- results when compared to CT value obtained from the rtRT-PCR. The diagnostic accuracy for RAT was 79.2% with kappa=0.59 showing moderate agreement and empirical benchmark was set with Youden’s Index 0.597 to be administered as diagnostic purposed. Conclusion: The RAT performed well as a POCT test for early diagnosis of COVID-19 in primary healthcare centers. More crucially finding from our study is that RTPCR proven SARS-CoV-2 infection and negative by RAT are not likely to be infectious. Keywords: SARS-CoV-2, rtRT-PCR, RAT, Sensitivity, Specificity