Alexandra K. Diem

Alexandra K. Diem
Simula Research Laboratory · Department of Computational Physiology

PhD Complex Systems Simulation

About

14
Publications
14,081
Reads
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294
Citations
Introduction
I develop computational models of biological flows across various scales based on porous media. During my PhD I developed models of waste clearance from the brain intramural periarterial drainage in an attempt to discover its mechanism of failure as a precursor for Alzheimer's disease. I disproved the often cited hypothesis that waste clearance is driven by arterial pulsations, and developing and providing the first evidence for a new hypothesis linking waste clearance to the biochemical signalling cascade of functional hyperaemia. Currently I work on the development of a cardiac perfusion model covering three orders of magnitude: from the large coronary arteries to the intramural capillaries and diffusion-reaction exchange of particles between capillaries and the myocardium.
Additional affiliations
December 2017 - present
Simula Research Laboratory
Position
  • Fellow
January 2017 - November 2017
University of Southampton
Position
  • Fellow
July 2015 - August 2015
University of Cape Town
Position
  • Researcher
Education
October 2012 - December 2016
February 2010 - June 2010
The University of Queensland
Field of study
  • Bioinformatics
October 2007 - March 2012
Friedrich Schiller University Jena
Field of study
  • Bioinformatics

Publications

Publications (14)
Article
Full-text available
Finite-differences methods such as the Lax-Wendroff method (LW) are commonly used to solve 1D models of blood flow. These models solve for blood flow and lumen area and are useful in disease research, such as hypertension and atherosclerosis, where flow and pressure are good indicators for the presence of disease. Despite the popularity of the LW m...
Article
Full-text available
The accumulation of soluble and insoluble amyloid-beta (A-beta) in the brain indicates failure of elimination of A-beta from the brain with age and Alzheimer's disease. There is a variety of mechanisms for elimination of A-beta from the brain. They include the action of microglia and enzymes together with receptor-mediated absorption of A-beta into...
Article
Full-text available
Perfusion is one of the most important processes maintaining organ health. From a computational perspective, however, perfusion is amongst the least studied physiological processes of the heart. The recent development of novel nanoparticle-based targeted cardiac therapy calls for novel simulation methods that can provide insights into the distribut...
Article
Full-text available
The mechanisms behind the clearance of soluble waste from deep within the parenchyma of the brain remain unclear. Experimental evidence reveals that one pathway for clearance of waste, termed intra-mural peri-arterial drainage (IPAD), is the rapid drainage of interstitial fluid along basement membranes (BM) of the smooth muscle cells of cerebral ar...
Article
Full-text available
Chemical Signalling in the Neurovascular Unit This is a replication of the following article: Witthoft A, Karniadakis GE (2012) A bidirectional model for communication in the neurovascular unit. Journal of Theoretical Biology 311: 80-93. where the authors present "an interactional model of bidirectional signalling in the neurovascular unit". Thi...
Article
Full-text available
Alzheimer's Disease (AD) is the most common form of dementia and to date there is no cure or efficient prophylaxis. The cognitive decline correlates with the accumulation of amyloid-β (Aβ) in the walls of capillaries and arteries. Our group has demonstrated that interstitial fluid and Aβ are eliminated from the brain along the basement membranes of...
Article
Full-text available
Computer science offers a large set of tools for prototyping, writing, running, testing, validating, sharing and reproducing results, however computational science lags behind. In the best case, authors may provide their source code as a compressed archive and they may feel confident their research is reproducible. But this is not exactly true. Jam...
Article
Full-text available
Alzheimer's disease is characterized by accumulation of amyloid-β (Aβ) in the brain and in the walls of cerebral arteries. The focus of this work is on clearance of Aβ along artery walls, the failure of which may explain the accumulation of Aβ in Alzheimer's disease. Periarterial basement membranes form continuous channels from cerebral capillaries...
Article
Full-text available
Here we review and extend models on different scales for a computing architecture made from networks of excitable chemical droplets. A system of lipid covered droplets containing reagents of the Belousov-Zhabotinsky (BZ) reaction has been used in our experiments as model system to study the signal transmission dynamics of chemical computers and the...

Questions

Question (1)
Question
I am currently working with an assumption of 10um width for an astrocyte end-foot and 1um gap, simply because I couldn't find any resources to give me a better idea, but I would like to obtain a more accurate estimate or find sources that back up my estimate.

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