Development of Physics Applied to Medicine in the UK, 1945–90

Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.First published by the Wellcome Trust Centre for the History of Medicine at UCL, 2006.©The Trustee of the Wellcome Trust, London, 2006.All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Annotated and edited transcript of a Witness Seminar held on 5 July 2005. Introduction by Dr Jeff Hughes.Organized with the assistance of Professor John Clifton (UCL) and chaired by Professor Peter Williams (Manchester), this seminar examined the early developments of medical physics in the UK between 1945 and 1990. Participants discussed a range of themes including medical physics before and during the war, the role of the King's Fund and the formation of the Hospital Physicists' Association (HPA), expansion of medical physics outside radiotherapy and to non-radiation physics (ultrasound, medical instrumentation, bioengineering, use of digital computers), developing regional services and links with industry. The seminar finished with a discussion on the changing scene in the 1980s, covering topics such as funding, academic and undergraduate medical physics, imaging, CT, NMR and others. Participants included Mr Tom Ashton, Dr Barry Barber, Professors Roland Blackwell and Terence Burlin, Dr Joseph Blau, Mr Bob (John) Burns, Professors John Clifton, David Delpy, Philip Dendy and Jack Fowler, Dr Jean Guy, Mr John Haggith, Drs John Haybittle, Alan Jennings and John Law, Professors John Mallard and Joe McKie, Mr David Murnaghan, Professor Angela Newing, Dr Sydney Osborn, Professor Rodney Smallwood, Dr Adrian Thomas, Dr Peter Tothill, Mr Theodore Tulley, Professors Peter Wells and John West, and Mr John Wilkinson. Christie D A, Tansey E M. (eds) (2006) Development of physics applied to medicine in the UK, 1945–90, Wellcome Witnesses to Twentieth Century Medicine, vol. 28. London: The Wellcome Trust Centre for the History of Medicine at UCL.The Wellcome Trust Centre for the History of Medicine at UCL is funded by the Wellcome Trust, which is a registered charity, no. 210183

Focal Spot, Winter 1983/84

https://digitalcommons.wustl.edu/focal_spot_archives/1036/thumbnail.jp

Model of unidirectional block formation leading to reentrant ventricular tachycardia in the infarct border zone of postinfarction canine hearts

AbstractBackgroundWhen the infarct border zone is stimulated prematurely, a unidirectional block line (UBL) can form and lead to double-loop (figure-of-eight) reentrant ventricular tachycardia (VT) with a central isthmus. The isthmus is composed of an entrance, center, and exit. It was hypothesized that for certain stimulus site locations and coupling intervals, the UBL would coincide with the isthmus entrance boundary, where infarct border zone thickness changes from thin-to-thick in the travel direction of the premature stimulus wavefront.MethodA quantitative model was developed to describe how thin-to-thick changes in the border zone result in critically convex wavefront curvature leading to conduction block, which is dependent upon coupling interval. The model was tested in 12 retrospectively analyzed postinfarction canine experiments. Electrical activation was mapped for premature stimulation and for the first reentrant VT cycle. The relationship of functional conduction block forming during premature stimulation to functional block during reentrant VT was quantified.ResultsFor an appropriately placed stimulus, in accord with model predictions: 1. The UBL and reentrant VT isthmus lateral boundaries overlapped (error: 4.8±5.7mm). 2. The UBL leading edge coincided with the distal isthmus where the center-entrance boundary would be expected to occur. 3. The mean coupling interval was 164.6±11.0ms during premature stimulation and 190.7±20.4ms during the first reentrant VT cycle, in accord with model calculations, which resulted in critically convex wavefront curvature and functional conduction block, respectively, at the location of the isthmus entrance boundary and at the lateral isthmus edges.DiscussionReentrant VT onset following premature stimulation can be explained by the presence of critically convex wavefront curvature and unidirectional block at the isthmus entrance boundary when the premature stimulation interval is sufficiently short. The double-loop reentrant circuit pattern is a consequence of wavefront bifurcation around this UBL followed by coalescence, and then impulse propagation through the isthmus. The wavefront is blocked from propagating laterally away from the isthmus by sharp increases in border zone thickness, which results in critically convex wavefront curvature at VT cycle lengths

Focal Spot, Winter 1983/84

https://digitalcommons.wustl.edu/focal_spot_archives/1036/thumbnail.jp

NASA guidelines on report literature

NASA seeks for inclusion in its Scientific and Technical Information System research reports, conference proceedings, meeting papers, monographs, and doctoral and post graduate theses which relate to the NASA mission and objectives. Topics of interest to NASA are presented

A Review of Atrial Fibrillation Detection Methods as a Service

Atrial Fibrillation (AF) is a common heart arrhythmia that often goes undetected, and even if it is detected, managing the condition may be challenging. In this paper, we review how the RR interval and Electrocardiogram (ECG) signals, incorporated into a monitoring system, can be useful to track AF events. Were such an automated system to be implemented, it could be used to help manage AF and thereby reduce patient morbidity and mortality. The main impetus behind the idea of developing a service is that a greater data volume analyzed can lead to better patient outcomes. Based on the literature review, which we present herein, we introduce the methods that can be used to detect AF efficiently and automatically via the RR interval and ECG signals. A cardiovascular disease monitoring service that incorporates one or multiple of these detection methods could extend event observation to all times, and could therefore become useful to establish any AF occurrence. The development of an automated and efficient method that monitors AF in real time would likely become a key component for meeting public health goals regarding the reduction of fatalities caused by the disease. Yet, at present, significant technological and regulatory obstacles remain, which prevent the development of any proposed system. Establishment of the scientific foundation for monitoring is important to provide effective service to patients and healthcare professionals

From Simple to Complex and Ultra-complex Systems:\ud A Paradigm Shift Towards Non-Abelian Systems Dynamics

Atoms, molecules, organisms distinguish layers of reality because of the causal links that govern their behavior, both horizontally (atom-atom, molecule-molecule, organism-organism) and vertically (atom-molecule-organism). This is the first intuition of the theory of levels. Even if the further development of the theory will require imposing a number of qualifications to this initial intuition, the idea of a series of entities organized on different levels of complexity will prove correct. Living systems as well as social systems and the human mind present features remarkably different from those characterizing non-living, simple physical and chemical systems. We propose that super-complexity requires at least four different categorical frameworks, provided by the theories of levels of reality, chronotopoids, (generalized) interactions, and anticipation