Medical Expertise, Patient Expertise Surrogate Decision-Making: The Importance of Co-deliberation in Medical Decision Making

In biomedicine, there are many cases where a patient is incapacitated and unable to make their medical decisions. Often, these patients have no declared decision-maker. This thesis explores solutions which promote these patients’ ability to receive beneficent care and have a respect for their autonomy by proposing a requirement for co-deliberation between a medical professional (medical expert) and someone who knows the patient well (patient expert). This thesis studies a case and applies three solutions: one where each expert has full authority and a final solution where the two experts co-deliberate. Co-deliberation is a conversation between the two experts to promote the best care for the patient while protecting the patient, whom has no declared/authorized decision maker

Calibration of the TWIST high-precision drift chambers

A method for the precise measurement of drift times for the high-precision drift chambers used in the TWIST detector is described. It is based on the iterative correction of the space-time relationships by the time residuals of the track fit, resulting in a measurement of the effective drift times. The corrected drift time maps are parametrised individually for each chamber using spline functions. Biases introduced by the reconstruction itself are taken into account as well, making it necessary to apply the procedure to both data and simulation. The described calibration is shown to improve the reconstruction performance and to extend significantly the physics reach of the experiment.Comment: 8 pages, 5 figure

REMODELING IN THE ACTIN CORE OF THE AUDITORY HAIR CELL STEREOCILIA AS A NOVEL COMPONENT OF TEMPORARY NOISE-INDUCED HEARING LOSS

The rigid, paracrystalline actin core of auditory hair cell stereocilia is extremely stable and after initial formation must persist for the life of the cell to preserve hearing in mammals. In healthy hair cells, turnover of actin molecules occurs only in a small region near the tips of stereocilia, while the actin filaments of the shaft are stable. For decades damage to the actin core of stereocilia from acoustic trauma has only been attributed to cases of permanent noise-induced hearing loss. Here, we show that repairable actin core damage occurs in temporary noise-induced hearing loss from moderate acoustic trauma. We have found that moderate noise exposure causing a temporary hearing loss results in damage to the stereocilia actin core in the form of small, submicron breaks in the filamentous actin (F-actin) at the base of the stereocilia, and displacement of the stereocilia from its anchoring rootlet. The same damages were recapitulated in vitro after mechanical overstimulation of stereocilia bundles by fluid-jet. Despite the well-established stable nature of the F-actin within stereocilia, 24 hours after the damage we observed complete repair of this damage in vitro and only partial repair in vivo, indicating slower in vivo recovery. The mechanism of this repair appears to involve actin remodeling in the upper portion of the rootlet located within the stereocilia shaft. Our results suggest that repairable damage to the F-actin at the base of stereocilia is a novel component of temporary noise-induced hearing loss. We believe that restoration of hearing thresholds after moderate noise exposure includes the repair of this damage. Although the exact mechanism of this repair is unknown, this is the first evidence for actin cytoskeleton repair in the stereocilia of auditory hair cells which have to maintain their structure and mechanosensitivity throughout the life of an organism

Resin film infusion mold tooling and molding method

A mold apparatus and method for resin film infusion molding including an outer mold tool having a facing sheet adapted to support a resin film and preform assembly. The facing sheet includes attachment features extending therefrom. An inner mold tool is positioned on the facing sheet to enclose the resin film and preform assembly for resin film infusion molding. The inner mold tool includes a plurality of mandrels positioned for engagement with the resin film and preform assembly. Each mandrel includes a slot formed therein. A plurality of locating bars cooperate with the slots and with the attachment features for locating the mandrels longitudinally on the outer mold tool

Low-Background In-Trap Decay Spectroscopy with TITAN at TRIUMF

An in-trap decay spectroscopy setup has been developed and constructed for use with the TITAN facility at TRIUMF. The goal of this device is to observe weak electron-capture (EC) branching ratios for the odd-odd intermediate nuclei in the $\beta\beta$ decay process. This apparatus consists of an up-to 6 Tesla, open-access spectroscopy ion-trap, surrounded radially by up to 7 planar Si(Li) detectors which are separated from the trap by thin Be windows. This configuration provides a significant increase in sensitivity for the detection of low-energy photons by providing backing-free ion storage and eliminating charged-particle-induced backgrounds. An intense electron beam is also employed to increase the charge-states of the trapped ions, thus providing storage times on the order of minutes, allowing for decay-spectroscopy measurements. The technique of multiple ion-bunch stacking was also recently demonstrated, which further extends the measurement possibilities of this apparatus. The current status of the facility and initial results from a $^{116}$In measurement are presented.Comment: Proceedings for the 2nd International Conference on Advances in Radioactive Isotope Science (ARIS2014

Trapped-ion decay spectroscopy towards the determination of ground-state components of double-beta decay matrix elements

A new technique has been developed at TRIUMF's TITAN facility to perform in-trap decay spectroscopy. The aim of this technique is to eventually measure weak electron capture branching ratios (ECBRs) and by this to consequently determine GT matrix elements of $\beta\beta$ decaying nuclei. These branching ratios provide important input to the theoretical description of these decays. The feasibility and power of the technique is demonstrated by measuring the ECBR of $^{124}$Cs.Comment: 9 pages, 9 figure

Breakdown of the Isobaric Multiplet Mass Equation for the A = 20 and 21 Multiplets

Using the Penning trap mass spectrometer TITAN, we performed the first direct mass measurements of 20,21Mg, isotopes that are the most proton-rich members of the A = 20 and A = 21 isospin multiplets. These measurements were possible through the use of a unique ion-guide laser ion source, a development that suppressed isobaric contamination by six orders of magnitude. Compared to the latest atomic mass evaluation, we find that the mass of 21Mg is in good agreement but that the mass of 20Mg deviates by 3{\sigma}. These measurements reduce the uncertainties in the masses of 20,21Mg by 15 and 22 times, respectively, resulting in a significant departure from the expected behavior of the isobaric multiplet mass equation in both the A = 20 and A = 21 multiplets. This presents a challenge to shell model calculations using either the isospin non-conserving USDA/B Hamiltonians or isospin non-conserving interactions based on chiral two- and three-nucleon forces.Comment: 5 pages, 2 figure