Q&A for Biomedical Engineering scientists

• Charoenchai Lueang-on

  Transcranial Doppler Ultrasound signals

  I am using Transcranial Doppler Ultrasound signals (Embolic signals) for training and testing a detection system in my project. It is difficult to find these signals in my country. Can anyone offerI am using Transcranial Doppler Ultrasound signals (Embolic signals) for training and testing a detection system in my project. It is difficult to find these signals in my country. Can anyone offer advice?

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    Mohammad Bagher Khodabakhshi replied

    Dear Charoenchai I used Esaote Xvision machine which records Doppler RF signals. It was very important for me to introduce an embolic detection algorithm on radio frequency (RF) signals. You canDear Charoenchai I used Esaote Xvision machine which records Doppler RF signals. It was very important for me to introduce an embolic detection algorithm on radio frequency (RF) signals. You can make a circulatory phantom for recording. You can find other informations about RF signals and US Phantom here: [1] K.Ramanarine,D.K.Nassiri,P.R.Hoskins,A.J.Lubbers,Validation of a New Blood Momicking Fluid for Use in Doppler Flow Test Objects, Ultrasound in Med. & Biol Vol. 24, No. 3, pp. 451–459, 1998 [2]M.G.A. Lipperts, L.D.C. Sauren, J.G. Maessen, A.P.G. Hoeks, W.H. Mess, “Quantification of Embolic Showers Using Radio-Frequency Based TCD Analysis”, Ultrasound in Medicine and Biology, Volume 35, Issue 3, March 2009, Pages 395-402 [3] Mohammad Bagher Khodabakhshi,Hamid Behnam,Hoda Poorasad Mehrabany; “Ultrasound Radio Frequency Signal Simulation Considering Doppler Effect Using Linear Time Variant Model”, American Journal of Biomedical engineering: 2011; 1(1): 1-6

    9 days ago
• Adrian Toader-Williams

  Enzymes, Protein’s Stability Mutation. Biological Transmutation & Isotopic Activity?

  Are there known internal factors within the living organism are the direct cause for mutations? Why does a substitution in nucleotide base pairs take place? Or perhaps non living mater that isAre there known internal factors within the living organism are the direct cause for mutations? Why does a substitution in nucleotide base pairs take place? Or perhaps non living mater that is near by as part of the life support medium of the living organism? Enzymes suffer transformations, modifications, mutate. If any isotopic activity is involved, what are the isotopes we may talk about or have under observation? What are the atoms we may look closer at? There are mechanisms, the internal or some external clocks and / or some physical events with chemical reactions implications that take place I believe. Are isotopic activities possible factors to trigger protein enzyme’s instability? Perhaps we should look at it closer to be able to identify not only possible triggers but also to better understand the mechanisms that mutations take place in their complexity. Or perhaps we have a combination of isotopic activity and other activities that interact? What is known, proved or at least of hypothetical nature in this area of concern? I hope I made myself understood as is not really my line of specialty. Thanks to all members in advance and perhaps we can work something out, a research project may be borne out of this as team work? It is multidisciplinary complex subject that perhaps is worthwhile to try to unveil. Adrian Toader-Williams