Wednesday, September 28, 2016

Paper Accepted

Congratulations to Owais Khan, whose paper "Non-Newtonian vs. numerical rheology: Practical impact of shear-thinning on the prediction of stable and unstable flows in intracranial aneurysms" was just accepted by Int J Numer Methods Biomed Eng.  Abstract below:

Computational fluid dynamics (CFD) shows promise for informing treatment planning and rupture risk assessment for intracranial aneurysms. Much attention has been paid to the impact on predicted hemodynamics of various modelling assumptions and uncertainties, including the need for modelling the non-Newtonian, shear-thinning rheology of blood, with equivocal results. Our study clarifies this issue by contextualizing the impact of rheology model against the recently-demonstrated impact of CFD solution strategy on the prediction of aneurysm flow instabilities. Three aneurysm cases were considered, spanning a range of stable to unstable flows. Simulations were performed using a high-resolution/accuracy (HR) solution strategy with Newtonian and modified-Cross rheology models, and compared against results from a so-called ‘normal resolution’ (NR) strategy. Time-averaged and instantaneous wall shear stress (WSS) distributions, as well as frequency content of flow instabilities and dome-averaged WSS metrics, were minimally affected by the rheology model, whereas numerical solution strategy had a demonstrably more marked impact when the rheology model was fixed. We show that point-wise normalization of non- Newtonian by Newtonian WSS values tended to artificially amplify small differences in WSS of questionable physiological relevance in already-low WSS regions, which might help to explain the disparity of opinions in the aneurysm CFD literature regarding the impact of non-Newtonian rheology. Towards the goal of more patient-specific aneurysm CFD, we conclude that attention seems better spent on solution strategy and other likely ‘first-order’ effects (e.g., lumen segmentation, choice of flow rates), as opposed to ‘second-order’ effects such as rheology.

Wednesday, September 16, 2015

Max Julian thesis defense

Congratulations to BSL Master's student Max Julian (aka Massimo Iuliano :-), on the (very) successful defense of his thesis, "Illustration-Inspired Visualization of Blood Flow Dynamics".  Thanks to Nick Woolridge and Mark Chignell, Max's thesis examiners, and a special shout out to my colleague and Max's co-supervisor, Peter Coppin from OCADU, whose creativity, drive, enthusiasm, and optimism in the face of adversity have made this art/science collaboration possible and successful.

KVS wins award at ECI conference

Congratulations to BSL alumnus Kristian Valen-Sendstad (affectionately known as KVS), who won an Outstanding Oral Presentation by a Young Scientist award at the 2nd ECI Conference on CFD in Medicine and Biology, for his invited talk "On the assumption of laminar flow in the cerebrovasculature: Implications for CFD insights into aneurysm initiation and rupture".

Yours truly was a co-chair of the conference, but was not involved in the judging, and didn't even know who the judges were!

Wednesday, July 29, 2015

An entertaining take on peer review

Please take a moment to read (if time and your library access allows) this letter to the editor from Bob Mulkern, on the subject of peer-review.  Wish I could post full text, but then there are those pesky copyright issues :-)

Monday, June 22, 2015

Student awards, SB3C 2015

Congratulations to BSL PhD student Muhammad Owais Khan, whose presentation "CFD simulation of transition to turbulence for Newtonian vs. non-Newtonian flow through a stenosis" won first prize at the Biotransport and Simulation PhD student competition of the 2015 Summer Biomechanics, Bioengineering, and Biotransport Conference in Snowbird, Utah. Here Owais is shown with proud co-authors Frank Loth, yours truly (with exit sign), Kristian Valen-Sendstad aka KVS, and some random guy in the background.

Congratulations also to BSL PhD student Resmi KrishnankuttyRema, whose presentation "Inlet flow rate variation and onset of flow instabilities in the carotid siphon" was  a finalist for the Biofluids PhD student competition.  Like Owais, Resmi knocked it out of the park with her talk, but faced some stiff competition.  Well done both!

Sunday, December 28, 2014

Making the case for basic science research

I can't say I was ever a huge fan of Neil deGrasse Tyson, but now I am. His clever (and accurate) tweets about winter solstice rituals aside, watch this interview, where he patiently, er, 'unpacks' Fareed Zakaria and the CNN viewership regarding the importance of basic science research.  And all without screed; just deft sardonicism.