Frank-starling control of a left ventricular assist device

A physiological control system was developed for a rotary left ventricular assist device (LVAD) in which the target pump flow rate (LVADQ) was set as a function of left atrial pressure (LAP), mimicking the Frank-Starling mechanism. The control strategy was implemented using linear PID control and was evaluated in a pulsatile mock circulation loop using a prototyped centrifugal pump by varying pulmonary vascular resistance to alter venous return. The control strategy automatically varied pump speed (2460 to 1740 to 2700 RPM) in response to a decrease and subsequent increase in venous return. In contrast, a fixed-speed pump caused a simulated ventricular suction event during low venous return and higher ventricular volumes during high venous return. The preload sensitivity was increased from 0.011 L/min/mmHg in fixed speed mode to 0.47L/min/mmHg, a value similar to that of the native healthy heart. The sensitivity varied automatically to maintain the LAP and LVADQ within a predefined zone. This control strategy requires the implantation of a pressure sensor in the left atrium and a flow sensor around the outflow cannula of the LVAD. However, appropriate pressure sensor technology is not yet commercially available and so an alternative measure of preload such as pulsatility of pump signals should be investigated.

Challenges in implementing evidence-based practice into mental health services

This paper highlights challenges in implementing mental health policy at a service delivery level. It describes an attempt to foster greater application of recovery-orientated principles and practices within mental health services. Notwithstanding a highly supportive policy environment, strong support from service administrators, and an enthusiastic staff response to training, application of the training and support tools was weaker than anticipated. This paper evaluates the dissemination trial against key elements to promote sustained adoption of innovations. Organisational and procedural changes are required before mental health policies are systematically implemented in practice.

Building an effective trade practices commission : the role of Professor Robert Baxt AO

Bob Baxt, the third Chairman of the Trade Practices Commission, served for a single three year term from 1988 to 1991. He followed Bob McComas, who had deliberately adopted a non-litigious approach to preserving the competitive process, believing that he understood business as an insider and that much of what it did was not anti-competitive, when correctly viewed. Baxt was far more pro-active in his approach, and more closely aligned with that of the first Chairman, Ron Bannerman. Baxt sought to push the frontiers of investigation and precedent, and perhaps, more significantly, sought to influence his Ministers, the government, public servants and public opinion about the need to expand the coverage of the Trade Practices Act, increase penalties and properly resource the Commission so that it could perform its assigned roles. This article examines Baxt’s early and on-going role in teaching Australian students and professionals through his interdisciplinary Trade Practices Workshops, the political context of Baxt’s tenure, including his relations with the Attorney-General ,Michael Duffy, and his skilful handling of the Queensland Wire case.

Frank and Stein : from research scientist to creative writer (a screenplay and exegesis)

The screenplay, “Perfect Blood” (Frank and Stein), is the first two-hour episode of a two-part television miniseries Frank and Stein. This creative work is a science fiction story that speculates on the future of Western nations in a world where petroleum is scarce. A major theme that has been explored in the miniseries is the tension between the advantages and dangers of scientific progress without regard to human consequences. “Perfect Blood” (Frank and Stein) was written as part of my personal creative journey, which has been the transformation from research scientist to creative writer. In the exegetical component of this thesis, I propose that a key challenge for any scientist writing science fiction is the shift from conducting empirical research in a laboratory-based situation to engaging in creative practice research. During my personal creative journey, I found that a predominant difficulty in conducting research within a creative practice-led paradigm was unleashing my creativity and personal viewpoint, practices that are frowned upon in scientific research. The aim of the exegesis is to demonstrate that the transformative process from science to art is not neat and well-structured. My personal creative journey was fraught with many ‘wrong’ turns. However, after reflecting on the experience, I realise that every varied piece of research that I undertook allowed me to progress to the next stage, the next draft of Frank and Stein. And via the disorder of the creative process, a screenplay finally emerged that was both structured and creative, which are equally essential elements in screenwriting.

Replication of the Frank-Starling response in a Mock Circulation loop

Mock circulation loops (MCLs) are used to evaluate cardiovascular devices prior to in-vivo trials; however they lack the vital autoregulatory responses that occur in humans. This study aimed to develop and implement a left and right ventricular Frank-Starling response in a MCL. A proportional controller based on ventricular end diastolic volume was used to control the driving pressure of the MCL’s pneumatically operated ventricles. Ventricular pressure-volume loops and end systolic pressure-volume relationships were produced for a variety of healthy and pathological conditions and compared with human data to validate the simulated Frank-Starling response. The non-linear Frank-Starling response produced in this study successfully altered left and right ventricular contractility with changing preload and was validated with previously reported data. This improvement to an already detailed MCL has resulted in a test rig capable of further refining cardiovascular devices and reducing the number of in-vivo trials.

A Taxonomy for Homework Used by Mental Health Case Managers When Working with Individuals Diagnosed with Severe Mental Illness

A survey was completed by 122 case managers describing the types of homework assignments commonly used with individuals diagnosed with severe mental illness (SMI). Homework types were categorized using a 12-item homework description taxonomy and in relation to the 22 domains of the Camberwell Assessment of Need (CAN). Case managers predominately reported using behaviourally based homework tasks such as scheduling activities and the development of personal hygiene skills. Homework focused on CAN areas of need in relation to Company, Psychological Distress, Psychotic Symptoms and Daytime Activities. The applications of the taxonomy for both researchers and case managers are discussed.

Letter To Robert Lowell

Poem