Time-Frequency Equivalence in Removing Sinusoidal Interference from Electrocardiograms
Brandon S. Coventry,
Cecil W. Thomas
Issue:
Volume 2, Issue 4, August 2014
Pages:
27-32
Received:
20 August 2014
Accepted:
6 September 2014
Published:
20 September 2014
Abstract: In recorded bioelectric signals, such as the electrocardiogram, sinusoidal interference from power lines or other sources causes distortion in the signal and may lead to misdiagnosis. For long or continuous recordings, adaptive filtering can be effective in minimizing the interference. For short recording, the options are limited. Subtractive methods have been used, but they do not distinguish between the interference and signal components with similar frequency. A new method can distinguish between signal and interference, so that the interference can be removed with very small residual error. In clinical recordings, the frequency of powerline interference is known, but the adaptive nature of the algorithm allows extension to cases when the frequency of interference is not known exactly.
Abstract: In recorded bioelectric signals, such as the electrocardiogram, sinusoidal interference from power lines or other sources causes distortion in the signal and may lead to misdiagnosis. For long or continuous recordings, adaptive filtering can be effective in minimizing the interference. For short recording, the options are limited. Subtractive metho...
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Rapid Detection of HIV-1 Subtypes in Ghana by Heteroduplex Mobility Assay
Nicholas Israel Nii-Trebi,
James Ashun Mensah Brandful,
William Kwabena Ampofo,
Billal Obeng Musah,
Jacob Samson Barnor,
Kenzo Tokunaga
Issue:
Volume 2, Issue 4, August 2014
Pages:
33-37
Received:
16 September 2014
Accepted:
22 September 2014
Published:
30 September 2014
Abstract: Background: In Ghana, the HIV-1 profile has been quite dynamic. Previous reports identified HIV-1 subtypes A, D and G present and recently the CRF02_AG has been described as the predominant molecular form of HIV-1 in Kumasi, Ghana. This underscores the need for constant molecular characterization of HIV-1 species in the country. Objective: To provide current updates on the nature of HIV subtypes in Ghana, there is need for a user-friendly tool for routine monitoring of subtypes in the absence of cost-intensive and skill-demanding sequencing techniques. This work demonstrates the use of heteroduplex mobility assay (HMA) for rapid subtype detection of HIV-1 isolated from Ghanaian patients. Method: Viruses from 15 antibody-positive HIV-1 patients were isolated directly by co-culturing peripheral blood mononuclear cells (PBMC) with phytohemagglutinin (PHA)-stimulated donor PBMCs from an HIV seronegative individual and through HeLa cells positive for CD4/CXCR4/CCR5 (MAGIC-5A cells). That was followed by proviral DNA extraction. Heteroduplex Mobility Assay (HMA) technique was then performed on the HIV gag gene. Results: Using the HMA technique, newly isolated HIV-1 strains were subtyped as follows: There were seven subtype A (47%), two subtype G (13%) and six (40%) A/G recombinants. Conclusion: The HIV-1 CRF02_AG in Ghana has spread much more rapidly than the previously predominant subtype A over the years. Constant molecular characterization of HIV strains is necessary to enable clear elucidation of the prevailing HIV species in Ghana. This study presents the HMA as a useful tool for monitoring subtype emergence and distribution in the country.
Abstract: Background: In Ghana, the HIV-1 profile has been quite dynamic. Previous reports identified HIV-1 subtypes A, D and G present and recently the CRF02_AG has been described as the predominant molecular form of HIV-1 in Kumasi, Ghana. This underscores the need for constant molecular characterization of HIV-1 species in the country. Objective: To provi...
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