Osgoode Digital Commons: An Update

Presentation delivered by F. Tim Knight at the Osgoode Hall Law School faculty meeting May 12, 2014

Sequential prostate MRI reporting in men on active surveillance: initial experience of a dedicated PRECISE software program

BACKGROUND AND OBJECTIVES: There is interest in using sequential multiparametric magnetic resonance imaging (mpMRI) to assess men on active surveillance (AS) for prostate cancer. The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations propose standardised reporting mpMRI data for these men. This includes accurate size measurements of lesions over time, but such approach is time consuming for the radiologist and there is a strong need of dedicated tools to report serial scans in a systematic manner. We present the results from an initial validation cohort using dedicated PRECISE reporting software to allow automated comparison between sequential scans on AS. MATERIALS AND METHODS: We retrospectively analysed baseline and follow-up scans of 20 men randomised to 6 months of daily dutasteride (n = 10) or placebo (n = 10) from the MAPPED trial. Men underwent 3T mpMRI at baseline and after 6 months, and a dedicated radiologist reported the scans using both a widespread commercially-available platform (Osirix®) and a semi-automated dedicated PRECISE reporting tool (MIM®). Tumour volume by planimetry in all sequences and conspicuity on diffusion-weighted imaging were assessed. Reporting time was recorded, and we used the Wilcoxon test for statistical analysis. RESULTS: Median tumour volumes and conspicuity were similar using both approaches. The reporting time of the follow-up scan was quicker using the PRECISE reporting workflow both in the whole population (12'33″ vs 10'52″; p = 0.005) and in the dutasteride arm (15'50″ vs 12'59″; p = 0.01). A structured report including clinical and imaging data was generated according to the PRECISE recommendations and a comparison table between lesion characteristics at baseline and follow-up scans was also included. CONCLUSION: We conclude that a dedicated PRECISE reporting tool for sequential scans in men on AS results in a significant reduction in the reporting time and allows the radiologist to easily compare scans over time. This tool will help with our understanding of the natural history of mpMRI changes during AS

Real-time buffer gas pressure tuning in a micro-machined vapor cell

We demonstrate a controllable depletion of the nitrogen buffer gas pressure in a micro-machined cesium (Cs) vapor cell from the dynamic heating of an alkali dispenser pill. When the alkali source is laser activated, the gettering compounds within the alkali pill dispenser reduce the nitrogen (N$_2$) content from the vapor for fine-tuning of the alkali to buffer gas pressure ratio. Additionally, we decrease the buffer gas pressure below 100$\,$mTorr to evaluate the presence of other potential broadening mechanisms. Real-time control of the gas pressure ratio in the vapor cell will have notable benefits for refining atomic sensor performance and provide a routine to achieve various target pressures across a wafer bonded with a uniform back-filled buffer gas pressure.Comment: 5 pages, 4 figure

High-Q Si3N4 Ring Resonators for Locking 780nm GaAs-Based Distributed Feedback Laser

High-Q microring resonators have applications in gyroscopes, frequency comb generation, and feedback systems to control narrow linewidth integrated lasers [1–3]. This paper demonstrates the highest Q values measured for microring resonators at 780 nm wavelength. These sub mm integrated cavities can be used to provide an error signal for locking a distributed feedback laser (DFB), Fig. 1(a), using the Pound-Drever-Hall (PDH) method. High stability DFBs can also be achieved using a micro-electro-mechanical system (MEMS) cell containing 87 Rb vapour and taking advantage of the absorption line at 780.24 nm. This provides an absolute reference for locking the laser but only to the 87 Rb transition wavelengths. The microring resonator can be tailor made for any wavelength but is susceptible to thermal effects; this could in part be overcome using a top cladding with a thermo-optic coefficient that counteracts that of the waveguide core

Micro-machined deep silicon atomic vapor cells

Using a simple and cost-effective water jet process, silicon etch depth limitations are overcome to realize a 6 mm deep atomic vapor cell. While the minimum silicon feature size was limited to a 1.5 mm width in these first generation vapor cells, we successfully demonstrate a two-chamber geometry by including a [Formula: see text] mm meandering channel between the alkali pill chamber and the main interrogation chamber. We evaluate the impact of the channel conductance on the introduction of the alkali vapor density during the pill activation process and mitigate glass damage and pill contamination near the main chamber. Finally, we highlight the improved signal achievable in the 6 mm silicon cell compared to standard 2 mm path length silicon vapor cells

Stand-alone vacuum cell for compact ultracold quantum technologies

Compact vacuum systems are key enabling components for cold atom technologies, facilitating extremely accurate sensing applications. There has been important progress toward a truly portable compact vacuum system; however, size, weight, and power consumption can be prohibitively large, optical access may be limited, and active pumping is often required. Here, we present a centiliter-scale ceramic vacuum chamber with He-impermeable viewports and an integrated diffractive optic, enabling robust laser cooling with light from a single polarization-maintaining fiber. A cold atom demonstrator based on the vacuum cell delivers 10 7 laser-cooled 87Rb atoms per second, using minimal electrical power. With continuous Rb gas emission, active pumping yields a 17 day time constant. A vacuum cell, with no Rb dispensing and only passive pumping, has currently kept a similar pressure for more than 500 days. The passive-pumping vacuum lifetime is several years, which is estimated from short-term He throughput with many foreseeable improvements. This technology enables wide-ranging mobilization of ultracold quantum metrology

Nitrogen buffer gas pressure tuning in a micro-machined vapor cell

We demonstrate a controllable depletion of the nitrogen buffer gas pressure in a micro-machined cesium (Cs) vapor cell from the dynamic heating of an alkali dispenser pill. When the alkali source is laser activated, the gettering compounds within the alkali pill dispenser reduce the nitrogen (N2) content from the vapor for fine-tuning of the alkali to buffer gas pressure ratio, with a demonstrated pressure step size as low as 1 Torr. Additionally, we decrease the buffer gas pressure below 100 mTorr to evaluate the presence of other potential broadening mechanisms. Real-time control of the gas pressure ratio in the vapor cell will have notable benefits for refining atomic sensor performance and provide a routine to achieve various target pressures across a wafer bonded with a uniform back-filled buffer gas pressure

Osgoode Digital Commons: An Update

Presentation delivered by F. Tim Knight at the Osgoode Hall Law School faculty meeting May 12, 2014

Rehabilitation after wrist fracture: A narrative review of outcome measures and protocols

INTRODUCTION: Wrist fractures represent the commonest fractures of upper limb. After the orthopedic surgical or conservative management, patients usually experience decrease of mobility, strength and function of wrist and hand, with consequent reduction of independence in daily life activities. For the management of the rehabilitative phase, a multitude of therapeutic approaches have been proposed, but a consensus on the program for rehabilitation of wrist fracture still lacks. Aim of this review was to describe the current literature evidence for rehabilitation after wrist fracture. EVIDENCE ACQUISITION: A search was performed using PubMed, Pedro and Scopus electronic databases for peer-reviewed literature related to rehabilitation of wrist fractures in adults published between January 2005 and April 2020. Only studies in English with participants older than 18 years were included and all types of study design were selected, except for systematic reviews, single case reports and congress proceedings. For each publication included, we reviewed the outcome measures and the rehabilitation program. EVIDENCE SYNTHESIS: We included 49 studies, reporting different rehabilitative protocols which integrate various approaches: advice, passive and active exercises, manual therapy and instrumental physiotherapy, sensorimotor and pharmacological interventions. We observed variability in terms of application (therapist-supervised versus self-administered home protocols), rehabilitation timing and outcome measures (objective measurement, evaluator-based scales, patient-reported outcome measures). CONCLUSIONS: After a wrist fracture, numerous rehabilitative approaches may be applied to reduce pain, enhance motility, increase strength and improve function of upper limb. On the basis of the current literature, we show a possible rehabilitative protocol after wrist fracture

Integrated DFB Lasers on Si3N4 Photonic Platform for Chip-Scale Atomic Systems

780 nm wavelength distributed feedback lasers have been integrated onto a Si3N4 photonic platform on a Si substrate and coupled into waveguides for laser locking to either a ring resonator or rubidium vacuum cell