96 research outputs found
Assessment of Knowledge-Based Planning for Prostate Intensity Modulated Proton Therapy
Purpose: To assess the performance of a proton-specific knowledge based planning (KBPP) model in creation of robustly optimized intensity-modulated proton therapy (IMPT) plans for treatment of patients with prostate cancer.
Materials and Methods: Forty-five patients with localized prostate cancer, who had previously been treated with volumetric modulated arc therapy, were selected and replanned with robustly optimized IMPT. A KBPP model was generated from the results of 30 of the patients, and the remaining 15 patient results were used for validation. The KBPP model quality and accuracy were evaluated with the model-provided organ-at-risk regression plots and metrics. The KBPP quality was also assessed through comparison of expert and KBPP-generated IMPT plans for target coverage and organ-at-risk sparing.
Results: The resulting R (2) (mean ± SD, 0.87 ± 0.07) between dosimetric and geometric features, as well as the χ(2) test (1.17 ± 0.07) between the original and estimated data, showed the model had good quality. All the KBPP plans were clinically acceptable. Compared with the expert plans, the KBPP plans had marginally higher dose-volume indices for the rectum V65Gy (0.8% ± 2.94%), but delivered a lower dose to the bladder (-1.06% ± 2.9% for bladder V65Gy). In addition, KBPP plans achieved lower hotspot (-0.67Gy ± 2.17Gy) and lower integral dose (-0.09Gy ± 0.3Gy) than the expert plans did. Moreover, the KBPP generated better plans that demonstrated slightly greater clinical target volume V95 (0.1% ± 0.68%) and lower homogeneity index (-1.13 ± 2.34).
Conclusions: The results demonstrated that robustly optimized IMPT plans created by the KBPP model are of high quality and are comparable to expert plans. Furthermore, the KBPP model can generate more-robust and more-homogenous plans compared with those of expert plans. More studies need to be done for the validation of the proton KBPP model at more-complicated treatment sites
Developing a portable gas imaging camera using highly tunable active-illumination and computer vision
We have developed a portable gas imaging camera for identifying methane leaks in real-time. The camera uses active illumination from distributed feedback InGaAs laser diodes tuned to the 1653 nm methane absorption band. An InGaAs focal plane sensor array images the active illumination. The lasers are driven off resonance every alternate frame so that computer vision can extract the gas data. A colour image is captured simultaneously and the data is superimposed to guide the operator. Image stabilisation has been employed to allow detection with a moving camera, successfully imaging leaks from mains pressure gas supplies at a range of up to 3 m and flow rates as low as 0.05 L min−1
Building relationships and facilitating immigrant community integration: An evaluation of a Cultural Navigator Program
Despite the United States’ long history of immigration, large and small communities around the country struggle to integrate newcomers into the social, economic, cultural, and political spheres of society. Utilizing results from the program evaluation of one public library’s Cultural Navigator Program (CNP), the authors illustrate how communities and public institutions can promote integration and relationship building between newly arrived immigrants and long-time residents. Existing social networks, conceptualized in this article as social capital, within receiving communities were leveraged to build capacity among newly arrived immigrants and foster inclusivity and integration at the community level. As a place of intervention, public libraries are suggested as a safe and shared space where community integration can be fostered. The program model is provided as an approach to immigrant community integration. Insights derived from the evaluation inform a discussion on engaging approaches to immigrant integration. The CNP utilized community networks to deliberately and systematically facilitate integration and relationship building between newly arrived immigrants and community members. Lessons learned and recommendations for program evaluators and administrators are provided
Sport, War and Democracy in Classical Athens
This article concerns the paradox of athletics in classical Athens. Democracy may have opened up politics to every class of Athenian but it had little impact on sporting participation. The city’s athletes continued to drawn predominantly from the upper class. It comes as a surprise then that lower-class Athenians actually esteemed athletes above every other group in the public eye, honoured them very generously when they won, and directed a great deal of public and private money to sporting competitions and facilities. In addition athletics escaped the otherwise persistent criticism of upper-class activities in the popular culture of the democracy. The research of social scientists on sport and aggression suggests this paradox may have been due to the cultural overlap between athletics and war under the Athenian democracy. The article concludes that the practical and ideological democratization of war by classical Athens legitimized and supported upper-class sport
PROMISING THE DREAM: changing destination image of London through the effect of website place
Drawing on theories of place identity and social identity, this study aims to fill a gap in place identity studies regarding the effect of a place website on the destination image of customers/visitors/tourists. The research addresses three questions: (1) what are the main impacts of tourists’ attitude on place identity and the place website, (2) what are the factors that influence destination image, and (3) what are the main impacts of a favorable destination image? The favorability of a destination image is reflected by the extent to which visitors positively regard that place website. Results reveal the importance of the destination image in enhancing the intention to revisit and recommend. Also, visitors’ satisfaction impacts on their intention to revisit and recommend the place. Significant implications for place managers and researchers are highlighted
The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra. \ua9 2015. The American Astronomical Society
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Technical aspects of spinal cord injections for cell transplantation. Clinical and translational considerations
Spinal cord injections may be used to transplant cellular suspensions for the experimental treatment of spinal cord injury. These injections cause some additional injury due to needle penetration, spinal cord motion during injection, creation of intraparenchymal pressure gradients and hydrodynamic dissection, instillation of a deforming cell mass and possible cord ischemia. It is important to understand these variables to maximize the safety of injections and avoid injury to spared structures. Surprisingly little knowledge exists regarding these variables. Further complicating spinal cord injections is the fact that intraparenchymal events are not evident during injections. As cell injections for spinal cord injury enter extensive clinical testing it is important to both optimize the procedures, and reduce the probability of technical failures. In this review current knowledge and key areas for knowledge advance are identified. These include a need for a more thorough understanding of how the spinal cord is affected by needle entry and dwell, needle-cord relative motion, instillation of highly concentrated cellular volumes, compliance of intact and damaged spinal cord tissue, radial tensile stresses and hydrodynamic forces created by injection, and the rates of pressure gradient dissipation in damaged and intact tissue. We propose that if the variables associated with injury can be identified, injection injury may be reduced and we illustrate the use of ultrasound to monitor injection in a spinal cord model. We also suggest that injectate backout or extrusion be reinterpreted as a clear indicator of excessive intraparenchymal pressure. The strengths and weaknesses of alternatives to direct intraparenchymal injection are also discussed
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