Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

Theorising international youth volunteering: training for global (corporate) work?

Ongoing globalisation poses a distinct challenge to how we understand what work ‘is’ in the contemporary world. Theoretical distinctions between the spatialities and temporalities of work as a practice have become blurred, along with understandings of work purely as an economic rather than a socio-cultural phenomenon. Building on theoretical approaches within geography and the ‘new sociology of work’, this paper argues that the transformation of work produced by contemporary globalisation requires a more sophisticated and geographically informed understanding of the spatiality of work as a practice. It develops this contention by presenting research into a specific kind of (unconventional) work – international youth volunteering. It argues that this form of work has a complex spatiality, whose constitution and impacts exceed the specific material location of workers in both space and time. Furthermore, it examines how this ‘multiplex mode’ of work practice destabilises the relationship between work and non-work, and facilitates the development of cultural capital, self-identity and skills in young people. It also contends that this form of voluntary work is embedded in the emerging needs of global labour markets. These arguments are elaborated through the presentation of research from a longitudinal project on the impacts of international youth volunteering. This research consists of data from interviews and focus groups with young people who undertook a range of different types of overseas voluntary work placement, and interviews with corporate recruiters in leading transnational firms concerning their understanding of the value (or otherwise) of international volunteering

A Limited Role for Suppression in the Central Field of Individuals with Strabismic Amblyopia.

yesBackground: Although their eyes are pointing in different directions, people with long-standing strabismic amblyopia typically do not experience double-vision or indeed any visual symptoms arising from their condition. It is generally believed that the phenomenon of suppression plays a major role in dealing with the consequences of amblyopia and strabismus, by preventing images from the weaker/deviating eye from reaching conscious awareness. Suppression is thus a highly sophisticated coping mechanism. Although suppression has been studied for over 100 years the literature is equivocal in relation to the extent of the retina that is suppressed, though the method used to investigate suppression is crucial to the outcome. There is growing evidence that some measurement methods lead to artefactual claims that suppression exists when it does not. Methodology/Results: Here we present the results of an experiment conducted with a new method to examine the prevalence, depth and extent of suppression in ten individuals with strabismic amblyopia. Seven subjects (70%) showed no evidence whatsoever for suppression and in the three individuals who did (30%), the depth and extent of suppression was small. Conclusions: Suppression may play a much smaller role in dealing with the negative consequences of strabismic amblyopia than previously thought. Whereas recent claims of this nature have been made only in those with micro-strabismus our results show extremely limited evidence for suppression across the central visual field in strabismic amblyopes more generally. Instead of suppressing the image from the weaker/deviating eye, we suggest the visual system of individuals with strabismic amblyopia may act to maximise the possibilities for binocular co-operation. This is consistent with recent evidence from strabismic and amblyopic individuals that their binocular mechanisms are intact, and that, just as in visual normals, performance with two eyes is better than with the better eye alone in these individuals

Thermal conductivity of high- T c superconductors

This paper reviews existing data on the thermal conductivity of high- T c superconductors. Included are discussions of pristine polycrystalline high- T c ceramics, single crystal specimens, and high- T c materials structurally modified by substitution or by radiation damage. The thermal conductivity of high- T c superconductors is compared with that of conventional superconductors, and dramatic differences are found between the two families. Mechanisms of thermal conductivity applicable to high- T c perovskites are discussed and implications for theories of high- T c superconductivity are noted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45121/1/10948_2004_Article_BF00617463.pd

The MEDD myth: the impact of pseudoscience on pain research and prescribing-guideline development

Jeffrey Fudin,1 Jacqueline Pratt Cleary,2 Michael E Schatman31Western New England University College of Pharmacy, Springfield, MA, 2Stratton VA Medical Center, Albany, NY, 3US Pain Foundation, Bellevue, WA, USAWith the opioid-misuse and -abuse problem on the rise, pain practitioners and lawmakers are scrambling for strategies to help mitigate opioid risks. Approaches include opioid-treatment agreements, urine drug testing, prescription-monitoring programs, assorted validated risk-assessment tools for abuse/misuse and opioid-induced respiratory depression (OIRD), biopsychosocial support, and other strategies.1–3 Nonopioid pain therapies should be considered and maximized prior to initiating opioid treatment; however, in some cases opioids are the optimal choice for both noncancer and cancer-related pain syndromes.

An integrated MR imaging coil and body-mounted robot for MR-guided pediatric arthrography: SNR and phantom study

© 2019 SPIE. In this paper we report development of an integrated RF coil for our body-mounted arthrography robot called Arthrobot. Arthrography is the evaluation of joint conditions using imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Current arthrography practice requires two separate stages; an intra-articular contrast injection guided by fluoroscopy or ultrasound followed by MR imaging. Our body-mounted robot is intended to enable needle placement in the MRI environment, streamlining the procedure. To improve imaging with our robot, a single loop coil was created and embedded into the mounting adaptor of the robot. This coil provides enough spatial coverage and sensitivity to localize anatomical points of interest and registration fiducials on the robot frame. In this paper we report the results of a SNR and heating study using our custom-made RF coil in four different scenarios using T1 and T2 weighted MR images: 1) no robot present, 2) robot off, 3) robot powered on, and 4) robot running. We also report an end-to-end robotic-assisted targeting study in a Philips MRI scanner suite using Arthrobot and our custommade RF coil for image acquisition. The SNR results and targeting results were promising. SNR dropped 32% for T1 weighted images compared to baseline (no robot present) images. For T2 weighted images the SNR drop was 42%. The average targeting error was 2.91 mm with a standard deviation (SD) of 1.82 mm. In future work we plan to replace the passive fiducials embedded in the base of Arthrobot with active fiducials that are tracked by the MRI system. These active fiducials will enable real-time tracking of the robot base and could allow breathing motion compensation during robotic procedures

Development of a convex polyhedral discrete element simulation framework for NVIDIA Kepler based GPUs

Understanding the dynamical behavior of Granular Media (GM) is extremely important to many industrial processes. Thus simulating the dynamics of GMis critical in the design and optimization of such processes. However, the dynamics of GM is complex in nature and cannot be described by a closed form solution for more than a few particles. A popular and successful approach in simulating the underlying dynamics of GM is by using the Discrete Element Method (DEM). Computational viable simulations are typically restricted to a few particles with realistic complex interactions or a larger number of particles with simplified interactions. This paper introduces a novel DEM based particle simulation code (BLAZEDEM) that is capable of simulating millions of particles on a desktop computer utilizing a NVIDIA Kepler Graphical Processor Unit (GPU) via the CUDA programming model. The GPU framework of BLAZE-DEM is limited to applications that require large numbers of particles with simplified interactions such as hopper flow which exhibits task level parallelism that can be exploited on the GPU. BLAZE-DEM also performs real-time visualization with interactive capabilities. In this paper we discuss our GPU framework and validate our code by comparison between experimental and numerical hopper flow.http://www.elsevier.com/locate/camhb201