237 research outputs found
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 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 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 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 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
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