Thin-film optoacoustic transducers for the subcellular Brillouin oscillation imaging of individual biological cells

Mechanical characterisation and imaging of biological tissue has piqued interest in the applicability to cell and tissue biology. One method, based on detection of Brillouin oscillations, has already lead to demonstrations on biological cells using ultrasound in the GHz range. In this paper we present a technique to extend this picosecond laser ultrasound technique from point measurements and line scans into high resolution acoustic imaging. Our technique uses a three layered metal-dielectric-metal film under the cell as a transducer for the generation of ultrasound. The design of this transducer and measuring system is optimised to address a limiting SNR factor related to the cell fragility; its sensitivity to laser light. Our approach shields the cell from laser radiation while having acoustic generation, optical detection and aiding heat dissipation. For that, Brillouin detection is performed in transmission rather than reflection. The conditions necessary to perform successfully this kind of detection are discussed and experimental results on phantom, fixed and living cells are presented

Quantitative elasticity measurement of urinary bladder wall using laser-induced surface acoustic waves

The maintenance of urinary bladder elasticity is essential to its functions, including the storage and voiding phases of the micturition cycle. The bladder stiffness can be changed by various pathophysiological conditions. Quantitative measurement of bladder elasticity is an essential step toward understanding various urinary bladder disease processes and improving patient care. As a nondestructive, and noncontact method, laser-induced surface acoustic waves (SAWs) can accurately characterize the elastic properties of different layers of organs such as the urinary bladder. This initial investigation evaluates the feasibility of a noncontact, all-optical method of generating and measuring the elasticity of the urinary bladder. Quantitative elasticity measurements of ex vivo porcine urinary bladder were made using the laser-induced SAW technique. A pulsed laser was used to excite SAWs that propagated on the bladder wall surface. A dedicated phase-sensitive optical coherence tomography (PhS-OCT) system remotely recorded the SAWs, from which the elasticity properties of different layers of the bladder were estimated. During the experiments, series of measurements were performed under five precisely controlled bladder volumes using water to estimate changes in the elasticity in relation to various urinary bladder contents. The results, validated by optical coherence elastography, show that the laser-induced SAW technique combined with PhS-OCT can be a feasible method of quantitative estimation of biomechanical properties

Construction of 3-Dimensional Printed Ultrasound Phantoms With Wall-less Vessels

Ultrasound phantoms are invaluable as training tools for vascular access procedures. We developed ultrasound phantoms with wall-less vessels using 3D printed chambers. Agar was used as a soft-tissue mimicking material, and the wall-less vessels were created with rods that were retracted after the agar was set. The chambers had integrated luer connectors to allow for fluid injections with clinical syringes. Several variations on this design are presented, which include branched and stenotic vessels. The results show that 3D printing can be well suited to the construction of wall-less ultrasound phantoms, with designs that can be readily customised and shared electronically

Chromophores in operative surgery: Current practice and rationalized development

BackgroundChromophore-containing molecules feature extensively in surgical practice, with synthetic dyes gaining popularity over endogenous optical adjuncts. New applications for chromophores in diagnostics and operative treatment exploit unique chemical structures suited for illuminating target tissues beyond the visual spectrum, ranging from ultraviolet (UV) to near-infrared (NIR). This review outlines the rationale for surgical chromophore application, the weaknesses and risks in each class of these compounds, and areas of foreseeable potential for employment of specialized contrast agents.MethodAn English-language literature search applied the following Boolean Search String: “dye OR Lake OR Stain OR chromophore” AND “tox$OR terato* OR carcino$ OR Allerg$OR surg$ OR clinic” using EMBASE, PUBMED, PUBMED central and OVIDSp, with back-referencing through Web of Knowledge™.ResultsBased on the primary literature, this study proposes a surgically relevant classification system of chromophores in current use, which facilitates risk/benefit consideration for the surgeon who employs them, and which facilitates clinically oriented development.ConclusionsThe next stage of development for optically active surgical adjuncts must address practical constraints whilst minimizing risks of adverse effects. Exploiting the technology's full potential also requires improvements in the usefulness of imagery equipment

Use of Outdoor Spaces and Microclimate in a Mediterranean Urban Area

This paper presents some of the findings of the European project, RUROS, concentrating on the effect of microclimatic conditions on the use of open spaces in an urban Mediterranean environment. The findings confirm that there is a strong relationship between microclimatic conditions and use of open spaces. Regarding the users of open spaces, a sensitivity to the summer heat was apparent for the age category >65. The spatial distribution of the interviewees demonstrates that in summer, visitors prefer to sit in shaded areas, whereas in autumn and winter sunlit areas are more popular. Observations of the use of space revealed that air temperature and solar radiation were found to be the most dominant parameters in relation to the use of space, with wind speed and relative humidity having a weak effect. In general, people prefer shaded areas at higher air temperatures. However, as high air temperature is a factor contributing to discomfort, overall presence is reduced when air temperature rises significantly. The preference of sun, differs from season to season, depending on the activities taking place in the areas (either designated or not). The diurnal pattern of the use of space also reveals a strong dependency on meteorological parameters. Regarding the time of maximum attendance, this is found in the evening during summer, while there is a transition of the time of maximum attendance towards noon as the season progresses from summer to winter. Daytime attendance figures of autumn and winter are 300-400% higher than in the summer. The need open spaces cover and the social ties provided may also be traced by analyzing the social composition of the interviewees and the reasons bringing them in the space

Robert Bruce : Works from the war (1943-1945)

"[D]rawings and paintings created by army artist Robert Bruce from 1943-1945." -- p. 2

Visible Evidence : Doric, Rodger, Thompson

Culjat gathers these three artists from British Columbia under their common concerns for horror, violence and destructive forces. Biographical notes. 4 bibl. ref

Unnamed Coffee Machine (UCM)

My project, the Unnamed Coffee Machine (UCM), is a drip style coffee machine inspired by American Brutalist architecture. It employs materials such as concrete, steel, and glass, and exhibits a raw, imposing stature directly reminiscent of its source materials. This document discusses the initial design brief, the research, ideation, planning, and design stages, and it showcases the construction process of the first functioning model of the UCM, including changes made and challenges encountered