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Risk from radionuclides: a frog's perspective : Accumulation of 137Cs in a riparian wetland, radiation doses, and effects on frogs and toads after low-dose rate exposureStark, Karolina January 2006 (has links)
Threats from man-made radionuclides include waste issues, increasing number of power plants, underground bomb testing, nuclear weapons, and “dirty bombs”. Until recently the ionizing radiation protection system focused on protecting humans with an implied protection of biota. However, goals of sustainable development and precautionary principles for human activity are leading to an inclusion of plant and animal populations in the protection system. From this perspective, the present thesis examines wetlands that function as sinks for the radionuclide 137Cs, and describes calculated and measured radiation doses to residing biota. Also, multi-level effects from exposure to low-dose rate ionizing radiation were studied. Accumulation of 137Cs after the Chernobyl accident fallout was studied in a riparian wetland with a mean activity concentration of 1 200 kBq m-2 in Sweden (paper I). A mass balance budget of 137Cs showed that the sedimentation of new material was balanced by the decay process of 137Cs in parts of the wetland (paper I). Frogs were identified as organisms of concern in this wetland. Internal radiation doses, based on whole body measurements of frogs, were estimated to be lower than external doses based on soil samples (paper II). Current dose models for biota resulted in a wide range of doses depending on different levels of conservatism in the models. Therefore, in situ measurements with frog-phantoms were found to provide valuable dose information (paper III). Measured doses using frog-phantoms were lower than calculated doses using several dose models. Although a dose conversion factor by FASSET was found to be useful for comparison with measurements in the field. A higher dose was measured to the phantom surface in comparison to inner parts, i.e. the sensitive skin of frogs receives the highest dose. Estimated and measured radiation doses to frogs were below suggested dose rate limits. Low-dose rate 137Cs exposure of eggs and tadpoles from three amphibian species, Scaphiopus holbrookii, Bufo terrestris, and Rana catesbeiana, showed no increased levels of strand breaks in red blood cells, and no effects on development, survival or growth up to metamorphosis (paper IV). The ecological factor larval density had a stronger effect on metamorphic traits than low-dose rate radiation. Higher levels of strand breaks were detected after an acute dose in R. catesbeiana than after a chronic dose supporting a dose rate limit for protection of amphibians rather than a dose limit (paper IV). Based on current knowledge, frogs in the contaminated wetland are probably not exposed to radiation doses from 137Cs that are harmful for the population. However, variations in sensitivity between populations and species, and adaptive responses have been shown for amphibians exposed to other stressors. This supports further research on effects of chronic low-dose rates of ionizing radiation on amphibians.
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Monte Carlo modeling of an x-ray fluorescence detection system by the MCNP codeLiu, Fang 17 March 2009 (has links)
An x-ray fluorescence detection system has been designed by our research group for quantifying the amount of gold nanoparticles presented within the phantom and animals during gold nanoparticle-aided cancer detection and therapy procedures. The primary components of the system consist of a microfocus x-ray source, a Pb beam collimator, and a CdTe photodiode detector. In order to optimize and facilitate future experimental tasks, a Monte Carlo model of the detection system has been created by using the MCNP5 code. Specifically, the model included an x-ray source, a Pb collimator, a CdTe detector, and an acrylic plastic phantom with four cylindrical columns where various materials such as gold nanoparticles, aluminum, etc. can be inserted during the experiments. In this model, 110 kVp x-rays emitted into a 60o cone from the focal spot of the x-ray source were collimated to a circular beam with a diameter of 5 mm. The collimated beam was then delivered to the plastic phantom with and without a gold nanoparticle-containing column. The fluence of scattered and gold fluorescence x-rays from the phantom was scored within the detector's sensitive volume resulting in various photon spectra and compared with the spectra acquired experimentally under the same geometry. The results show that the current Monte Carlo model can produce the results comparable to those from actual experiments and therefore it would serve as a useful tool to optimize and troubleshoot experimental tasks necessary for the development of gold nanoparticle-aided cancer detection and therapy procedures.
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Development and testing of a haptic interface to assist and improve the manipulation functions in virtual environments for persons with disabilities [electronic resource] / by Rohit Tammana.Tammana, Rohit. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 163 pages. / Thesis (M.S.M.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Robotics in rehabilitation provides considerable opportunities to improve the quality of life for persons with disabilities. Computerized and Virtual Environment (VE) training systems for persons with disabilities, many of which utilize the haptic feedback, have gained increasing acceptance in the recent years. Our methodology here is based on creating virtual environments connected to a haptic interface as an input device. This robotic setup introduces the advantages of the haptic rendering features in the environment and also provides tactile feedback to the patients. This thesis aims to demonstrate the efficacy of assistance function algorithms in rehabilitation robotics in virtual environments. Assist functions are used to map limited human input to motions required to perform complex tasks. The purpose is to train individuals in task-oriented applications to insure that they can be incorporated into the workplace. / ABSTRACT: Further, Hidden Markov Model (HMM) based motion recognition and skill learning are used for improving the skill levels of the users. For the Hidden Markov Model based motion recognition, the user's motion intention is combined with environment information to apply an appropriate assistance function. We used this algorithm to perform a commonly used vocational therapy test referred to as the box and the blocks test. The Hidden Markov Model based skill approach can be used for learning human skill and transferring the skill to persons with disabilities. A relatively complex task of moving along a labyrinth is chosen as the task to be modeled by HMM. This kind of training allows a person with disability to learn the skill and improve it through practice. Its application to motion therapy system using a haptic interface helps in improving their motion control capabilities, tremor reduction and upper limb coordination. / ABSTRACT: The results obtained from all the tests demonstrated that various forms of assistance provided reduced the execution times and increased the motion performance in chosen tasks. Two persons with disabilities volunteered to perform the above tasks and both of the disabled subjects expressed an interest and satisfaction with the philosophy behind these concepts. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
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Assistive force feedback for path following in 3D space for upper limb rehabilitation applicationsSwaminathan, Ramya 01 June 2007 (has links)
The primary objective of this research was the design of an easy to use C++ Graphical User Interface (GUI) which helps the user to choose the task that he/she wants to perform. This C++ application provides a platform intended for upper arm rehabilitation applications. The user can choose from different tasks such as: Assistive Function in 3D Space to Traverse a Linear Trajectory, User Controlled Velocity Based Scaling, Fitts' Task in X, Y, Z Directions. According to a study conducted by the scientific journal of the American Academy of Neurology, stroke patients aided by robotic rehabilitation devices gain significant improvement in movement. They also indicate that both initial and long term recovery are greater for patients assisted by robots during rehabilitation. This research aims to provide a haptic interface C++ platform for clinicians and therapists to study human arm motion and also to provide assistance to the user.
The user would get to choose andperform repetitive tasks aimed at improving his/her muscle memory. About eight healthy volunteers were chosen to perform a set of preliminary experiments on this haptic integrated C++ platform. These experiments were performed to get an indication of the effectiveness of the assistance functions provided in this C++ application. The eight volunteers performed the Fitts' Task in X, Y and Z directions. The subjects were divided into two groups, where one of the groups was given training without assistance and the other was given training with assistance. The execution time for both the groups was compared and analyzed. The experiments performed were preliminary, however some trends were observed: the people who received training with assistive force feedback took less execution time compared to those who were given training without any assistance. The path following error was also analyzed.
These preliminary tests were performed to demonstrate the haptic platform's use as a therapeutic assessment application, a rehabilitation tool and a data collection system for clinicians and researchers.
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The American Film Musical Genre Today: A New Breed or Just More of the Same? : The Development of the American Film Musical 2000-2013 / Den amerikanska filmmusikal-genren idag: Något nytt eller bara mer av samma sak? : Utvecklingen av den amerikanska filmmusikalen 2000-2013Askerfjord, Christer January 2014 (has links)
Since the introduction of synchronized sound at the end of the 1920s the film musical has had a special place in American film. But even with that special place the interest in the film musical has varied a lot during the 20th century. From the high interest during the “Golden Age” in the 1930s, 1940s, and 1950s, through low interest in the following decades and then renewed interest in musicals with the animated film musicals from Disney in the 1990s. But what has happened after the millennium? Has there been any development in the American film musical genre or is it just more of the same? This thesis tries to answer the question by analyzing three successful film musicals from the period 2001-2013, Moulin Rouge! (Baz Luhrmann, 2001), The Phantom of the Opera (Joel Schumacher, 2004), and Les Misérables (Tom Hooper, 2012) and comparing them to classical traditional musicals. According to this thesis there is a split answer, some areas of the classical American film musical have developed while other areas still remains the same.
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Att smärtlindra en obefintlig extremitet : Upplevelser av fantomsmärtans komplexitet / How to alleviate pain in a non existing extremity – experiences and complexity of the phantom limb painPalm Annerstedt, Caroline, Sjösten, Nina, Cardell, Amanda January 2014 (has links)
Fantomsmärta är ett komplext fenomen som drabbar många patienter efter amputation av extremitet. Syftet var att utforska hur fantomsmärtor efter amputation av extremitet kan upplevas och lindras. Litteraturstudiens resultat utgörs av 15 vetenskapliga artiklar som presenteras i tre huvudteman vilka är fantomsmärtans komplexitet, lindring genom transkutan elektrisk nervstimulering och lindring genom rörelseterapi. Det har visat sig att upplevelsen av fantomsmärta medför en negativ påverkan för patienter efter amputation av extremitet. Olika behandlingsmetoder till exempel transkutan elektrisk nervstimulering och rörelseterapi har beprövats med varierande resultat. Vidare forskning är nödvändig för att klarlägga den bakomliggande patofysiologin gällande fantomfenomenet för att generera bättre anpassade lindringsmetoder. Vidare forskning är även angelägen för att få en ökad förståelse för patienters upplevelser kring smärtproblematiken. Utformande av PM gällande vård av patienter som lider av fantomsmärtor efter amputation av extremitet vore betydelsefulla. / Phantom limb pain is a complex phenomenon that affects numerous patients following amputation of the extremities. The aim of this study was to explore how phantom limb pain following amputation of extremities can be experienced and alleviated. The study was conducted as a literature review where 15 scientific articles were the basis for the results. Three major themes are presented in the result: the complexity of phantom limb pain, alleviation through transcutaneous electrical nerve stimulation and alleviation through movement therapy. It has been shown that the experiences of phantom limb have a negative impact on patients following amputation of extremities. Different options regarding treatment, for example transcutaneous electrical nerve stimulation and movement theory, has been proven with variation in the results. Further research is required to elucidate the underlyingpathophysiology regarding the phantom phenomenon for better understanding and suitable alleviation options. Specific guidelines regarding nursing for patients who suffer from phantom limb pain would be of importance.
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Evaluation of a novel phantom‑based neurosurgical training systemMüns, Andrea, Meixensberger, Jürgen, Lindner, Dirk 15 December 2014 (has links) (PDF)
Background: The complexity of neurosurgical interventions demands innovative training solutions and standardized evaluation methods that in recent times have been the object of increased research interest. The objective is to establish an education curriculum on a phantom‑based training system incorporating theoretical and practical components for important aspects of brain tumor surgery. Methods: Training covers surgical planning of the optimal access path based on real patient data, setup of the navigation system including phantom registration and navigated craniotomy with real instruments. Nine residents from different education levels carried out three simulations on different data sets with varying tumor locations. Trainings were evaluated by a specialist using a uniform score system assessing tumor identification, registration accuracy, injured structures, planning and execution accuracy, tumor accessibility and required time. Results: Average scores improved from 16.9 to 20.4 between first and third training. Average time to craniotomy improved from 28.97 to 21.07 min, average time to suture improved from 37.83 to 27.47 min. Significant correlations were found between time to craniotomy and number of training (P < 0.05), between time to suture and number of training (P < 0.05) as well as between score and number of training (P < 0.01). Conclusion: The training system is evaluated to be a suitable training tool for residents to become familiar with the complex procedures of autonomous neurosurgical planning and conducting of craniotomies in tumor surgeries. Becoming more confident is supposed to result in less error‑prone and faster operation procedures and thus is a benefit for both physicians and patients.
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Fabrication and Characterization of New Passive and Active Polymer Gels with Tailored PropertiesIn, Eunji 01 January 2011 (has links)
In this thesis, three different types of polymer-based gels are fabricated and characterized for passive and active applications. Silica aerogel is a 3D mesoporous solid material that can be used for thermal insulation or in the biomedical industry. In this thesis, silica aerogel is cross- linked with diisocyanate to improve its strength and flexibility, which greatly opens up the range of applications. Then, soft polymer gel with tissue equivalent characteristics is fabricated to mimic the spin-lattice (T1) and spin-spin (T2) relaxation times for the magnetic resonance imaging (MRI) phantom of a liver with lesions. This study demonstrates a relationship between the composition of a gelling agent, and T1 and T2 modifiers on its dielectric, mechanical and imaging properties. Finally, an ionic electroactive polymer (EAP) that can be actuated on an electric field is fabricated, and its swelling and bending behaviours on design parameters are closely examined.
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Fabrication and Characterization of New Passive and Active Polymer Gels with Tailored PropertiesIn, Eunji 01 January 2011 (has links)
In this thesis, three different types of polymer-based gels are fabricated and characterized for passive and active applications. Silica aerogel is a 3D mesoporous solid material that can be used for thermal insulation or in the biomedical industry. In this thesis, silica aerogel is cross- linked with diisocyanate to improve its strength and flexibility, which greatly opens up the range of applications. Then, soft polymer gel with tissue equivalent characteristics is fabricated to mimic the spin-lattice (T1) and spin-spin (T2) relaxation times for the magnetic resonance imaging (MRI) phantom of a liver with lesions. This study demonstrates a relationship between the composition of a gelling agent, and T1 and T2 modifiers on its dielectric, mechanical and imaging properties. Finally, an ionic electroactive polymer (EAP) that can be actuated on an electric field is fabricated, and its swelling and bending behaviours on design parameters are closely examined.
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Monte Carlo simulations for Homeland Security using anthropomorphic phantomsBurns, Kimberly A. 17 March 2008 (has links)
After a radiation dispersion device (RDD) event, there may be internally and/or externally contaminated victims. After the RDD event, victims may require immediate medical assistance prior to decontamination. The dose rates to which a healthcare provider is exposed due to the internal and external contamination of the victim were computed using Monte Carlo simulations and five anthropomorphic phantoms. The dose rates to which the victim is exposed due to his/her own external contamination were also computed. For the external contamination modeling, the contamination is assumed to be distributed over the entire exterior of the victimâ s body. The geometrical models of the human body were based on the MIRD stylized phantom. The specific isotopes considered were 60Co, 137Cs, 131I, 192Ir, and 241Am. The surface contamination was generated by creating a 2-mm thick layer adjacent to the outside of the skin of the victim and uniformly sampling the emissions of the radioactive sources throughout this volume. The attending healthcare provider was assumed to be standing 20 cm from mid-torso of the victim. The organ absorbed doses in both the contaminated individual and a healthcare professional were computed. The effective dose to the victim and the attending healthcare professional were computed using the tissue weighting factors in ICRP Publication 60. For example, the dose rate to a reference male healthcare provider from the victim six hours after the inhalation of one ALI by an adipose male victim will be 0.277 mSv/hr. In addition, the air kerma was computed at different distances from the surfaces of the victim phantom and ratios were generated for the air kerma and the effective dose due to the victim from the surface contamination on the victim.
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