No description available.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (MTech Biomedical Technology)--Cape Peninsula University of Cape Town, 2005 / In clinical radiotherapy, experiments are performed to determine optimal conditions of the radiation prior to radiotherapy. These experiments focus on the relative biological effectivness(RBE) determination and are predominantly applied in high linear energy transfer (LET) radiations i.e. fast neutrons, as the RBE values for such radiations vary greatly. In general, the RBE of a certain radiation relative to a given reference radiation flCo gamma) varies widely with the energy, dose, dose rate, fractionation, type of tissue and end-point used. Experience with neutron therapy at iThemba LABS has shown that treatment with more fractions and lower doses per fraction may be beneficial for some patients. To calculate the iso-effective treatment dose needed, an appropriate alp ratio for early effects is needed. In this study, the repair of mouse jejunum was measured for split-dose irradiations to determine if a suitable alP ratio for neutrons could be estimated using the known value for gamma rays and the applicable RBE.. Crypt stem cell survival was measured 3.5 days after split-dose exposures to p(66)/Be neutrons and 6OCo gamma rays. Dose response curves for both treatment modalities and for both acute and fractionated exposures were constructed by counting crypts of Leiberkhiin at the base of the villi in haematoxylin and Eosin-stained sections of mouse jejunum. Using a RBE value of 1.64 and an alP ratio of 7Gy noted for tbe fractionated photon exposures, an alP ratio of 11.5 IV could be estimated for neutrons.

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Firmware development for Low-Level Controllers is an extremely complex task. Single-threaded microcontrollers are most commonly used for these controllers and thus are only capable of executing a single task at a time. Microcontroller software tends to be designed for an extremely specific task with little room for scalability or code reuse. Additionally, the state of a microcontroller at run-time is very difficult to observe and thus makes it harder to debug and develop these control systems. To alleviate these development issues, a software framework was designed to simplify firmware development for Hardware Abstract Layered (HAL) control systems. The software framework was implemented on Texas Instruments TM4C123GXL Tivas on a multi-joint robot with the purpose of experimenting on a distributed microcontroller system. All of the software for the microcontroller was implemented into one program with initialization files from the high-level controller to configure each individual Tiva based on its functionality in the distributed system. The EtherCAT communication protocol is used primarily for its fast communication speed between high-level and low-level controllers. A basic GUI development environment accompanies the framework to aid in the initial development of a custom controller firmware and thus reduce development time. Additionally, this framework is designed to be easily scalable such that a real-time operating system (RTOS) can be implemented with minimal effort should the developer desire to do so. The proposed software framework thus overcomes major challenges when developing firmware for low-level controllers making development overall less time-consuming. Further, this framework can be used for many different robotic applications with a low-level multi-layered control architecture. / Master of Science / Microcontrollers and embedded systems are used everywhere in our daily lives in the technology we love. From microwaves, to cars, to phones, to toaster ovens, these systems are implemented in practically every piece of technology we use on a daily basis. Software development of these systems tends to be extremely complicated and complex. Hence, the software designed for these systems is usually overly specific to the device with little room for code reuse and/or scalability. This issue is extremely present in the field of robotics. To alleviate this issue, this work proposed, designed, and implemented a software framework for microcontrollers in a distributed network for robotics applications. Additionally, a graphical interface was developed to customize the software framework for a developer's specific needs regarding what the application needs to do.

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No description available.

A mucosite oral constitui efeito colateral dose-limitante da quimioterapia, relativamente freqüente, desconfortável e potencialmente letal. O controle terapêutico é sintomático e ainda inexiste procedimento estabelecido para prevenir a sua manifestação. O objetivo deste estudo foi verificar a eficácia do laser de baixa potência na prevenção da mucosite oral e as influências de variáveis demográficas (idade e sexo), subjetivas (xerostomia e paladar) e objetivas (história médica), em pacientes portadores de adenocarcinoma de cólon, submetidos à quimioterapia com fluorouracil (5-FU) e ácido folínico (Leucovorin®). Quarenta e oito pacientes foram incluídos no estudo. 18 homens e 30 mulheres, na faixa etária dos 37 aos 78 anos com média de idade de 62,5 anos. Os pacientes foram endereçados, seqüencial e alternadamente, para dois grupos. Vinte e cinco pacientes compuseram o grupo submetido à aplicação preventiva de laser (grupo LP) e 23 pacientes receberam aplicação placebo (grupo C). A aplicação do laser, preventivo ou placebo, foi realizada na semana de infusão da quimioterapia, uma única vez, e os pacientes foram reavaliados após sete dias. O laser utilizado foi o AlGaInP, 660nm, fluência de 3J/cm2. Os graus de mucosite foram mensurados pela escala WHO, e a xerostomia e a dor por escala visual analógica (VAS). Os pacientes que desenvolveram mucosite receberam aplicação terapêutica de laser, independentemente a que grupo pertencesse. Vinte e um pacientes cumpriram os seis ciclos programados de quimioterapia (10 C e 11 LP), e 27 pacientes completaram apenas parte do protocolo (13 C e 14 LP). Houve ocorrência similar de mucosite oral entre os grupos, cuja freqüência variou em torno de 50% em cada ciclo, com a seguinte distribuição média: 22% de mucosite grau 1, 18% de grau 2, 10% de grau 3 e nenhum grau 4. Foram registrados 95 episódios de mucosite nos 188 ciclos de quimioterapia dos 48 pacientes incluídos no estudo. Nos 126 ciclos dos 21 pacientes que cumpriram todo o protocolo ocorreram 63 episódios de mucosite. A análise estatística não mostrou diferença significativa quanto à ocorrência de mucosite entre os grupos. Os pacientes do sexo feminino, pacientes acima de 60 anos de idade e a queixa de xerostomia prévia à quimioterapia, embora tenham mostrado tendência a diferença em alguns ciclos, não mantiveram essa característica na análise integral dos resultados. Pacientes com queixa de alteração de paladar prévio à quimioterapia e história de diabetes mellitus e gastrite manifestaram quadros mais graves de mucosite que a média geral da população estudada. O efeito benéfico do laser terapêutico foi altamente significante para os pacientes que desenvolveram mucosite oral. Concluiu-se que uma única aplicação de laser de baixa potência não foi efetiva para prevenir a mucosite oral na população estudada. Pacientes portadores de diabetes, gastrite, queixa de alteração de paladar e aqueles que manifestam graus mais severos de mucosite nos ciclos iniciais da quimioterapia merecem maior atenção no seguimento em função do pior prognóstico demonstrado neste estudo. / Oral mucositis is a debilitating, dose-limited complication of chemotherapy, fairly common, debilitating and potentially lethal. Its treatment is symptomatic and there are no preventive guidelines available yet. The purpose of this study was to evaluate the efficacy of low level laser therapy (LLLT) in oral mucositis prevention and the influence of demographic (age, gender), subjective (xerostomia, taste) and objective (medical history) factors as well. Forty-eight colorectal adenocarcinoma patients submitted to fluorouracil (5-FU) and folinic acid (Leucovorin®) chemotherapy protocol were enrolled in the trial, 18 men, 30 women, ranging from 37 to 78 y.o., mean 62,5 years. Two study groups were sequentially and alternately constituted. Twenty-five patients were submitted to a preventive laser treatment (LP group) and 23 received a placebo irradiation (C group). Laser treatment, effective or placebo, was delivered one time at the beginning of the chemotherapy infusion week. Every patient was reevaluated seven days after. An AlGaInP device, 660nm, was utilized with 3J/cm2 of fluency. Oral mucositis were graded according to WHO scale. Pain and xerostomia levels were evaluated through visual analogue scale (VAS). Patients who presented oral mucositis received therapeutic laser sessions, no matter to which group they were originally driven to. Twenty-one patients undergone all six cycles of the chemotherapy protocol planned (10C, 11LP) and 27 patients accomplished only partially the chemotherapy cycles (13C, 14LP). Oral mucositis were similarly distributed between the groups studied, around 50% in every cycle: 22% of grade 1 mucositis, 18% grade 2, 10% grade 3 and none grade 4. Ninety-five oral mucositis episodes were observed in the 188 cycles followed by the 48 patients in the study group; and 63 oral mucositis episodes were registered among the 21 patients followed through 126 chemotherapy cycles. Statistical analysis showed no difference between the groups on oral mucositis manifestation. The aspects of female gender, aged over 60 and xerostomia symptoms previous to chemotherapy, showed a slight difference in some cycles but no overall statistic significance was demonstrated. Patients with taste impairment previous to chemotherapy, history of diabetes and gastritis showed more severe pictures of mucositis than the overall population studied. Laser treatment was highly effective for patients who exhibited high grade oral mucositis. We concluded that a unique LLLT irradiation was ineffective as a preventive procedure for oral mucositis in the population evaluated. In addition, patients with diabetes, gastritis, taste impairment and patients who develop severe pictures of mucositis at the beginning of chemotherapy regimens should receive more attention since they exhibited poor prognosis in this research.

"Radionuclides in particulate matter associated with outdoor and indoor dusts were analyzed to determine the form and concentration of radioactive isotopes present. These radioactive isotopes, such as Strontium 90, Cesium 137, and Uranium 235, consist of, or are sorbed onto fine particulate matter, (PM). The airborne dispersion of this fine particulate matter results in the facilitated transport of these sorbed or neat radionuclides. Sources of particulate-bound radioactive contaminants include fallout from weapons testing, accumulation of radon daughters, transport of soils containing naturally-occurring radioactive material, remediation of radiologically-contaminated sites, and nuclear material processing. Radiological contaminants in PM, may exist as trace contamination in homogenous collections of particles, but may also exist heterogeneously, as a small number of high-concentration radionuclides among a larger set of uncontaminated particles. A total of 114 samples of indoor and outdoor airborne dusts were collected from a former nuclear weapons production facility near Richland, WA, the Los Alamos National Laboratory, and the Yakama Indian Nation in Wapato, WA. Los Alamos, NM was also the site of the May 2000 Cerro Grande wildfire. The wildfire created very large amounts of airborne particulate matter, including smoke and soot. The area affected by open burning included 43,000 acres. At the national laboratory, greater than 7600 acres were affected, including some areas that were radiologically- contaminated, such as a U-238 ammunition firing area. (LANL, 2007) This introduces a potential source of hot particles in dusts and other archived particulate matter, which may remain in the environment. LANL Airborne radionuclide surveillance has historically found higher uranium levels during windy periods, and saw elevated air uranium levels associated with the Cerro Grande fire. (Ibid, p. 108) Dust samples were sieved to pass a 150 micron screen and analyzed by gamma spectroscopy. Samples with higher activity were analyzed by Scanning Electron Microscopy/Energy Dispersive X-ray analysis, SEM/EDS. The results of gamma spectroscopy and individual particle counts were compared to determine the degree of radioactive heterogeneity in each sample. Radioactive heterogeneity, isotopic distribution, and particle size can be related to the source of the radioactive PM. Radiological contaminants in particulate matter, (PM), may exist as trace contamination in homogenous collections of particles, but may also exist heterogeneously, as a small number of high-concentration radionuclides among a larger set of uncontaminated particles. Residential and source area dusts were collected from locations surrounding, and potentially impacted, by operational and remedial activities at the HNR. The dust samples were analyzed, by multiple means, in order to identify those with radiologically- contaminated particles. Samples with higher activity were further analyzed by Scanning Electron Microscopy/Energy Dispersive X-ray analysis, (SEM/EDS), to determine if the radiological contamination was homogenous or heterogeneous. Two case studies were followed. The method isolated and analyzed lead and bismuth from naturally occurring radioactive material in coal fly ash. The method isolated and fingerprinted thorium, and the rare earths cerium, lanthanum, samarium, neodymium, and gadolinium in sedimentary cerium monazite minerals, nuclear waste processing dusts, and fission waste products in a WWTP effluent channel."

Identifying finger and wrist flexion based actions using single channel surface electromyogram have a number of rehabilitation, defence and human computer interface applications. These applications are currently infeasible because of unreliability in classification of sEMG when the level of muscle contraction is low and when there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during maintained wrist and finger flexion. It has been established in literature that surface electromyogram (sEMG) and other such biosignals are fractal signals. Some researchers have determined that fractal dimension (FD) is related to strength of muscle contraction. On careful analysis of fractal properties of sEMG, this research work has established that FD is related to the muscle size and complexity and not to the strength of muscle contraction. The work has also identified a novel feature, maximum fractal length (MFL) of the signal, as a good measure of strength of contraction of the muscle. From the analysis, it is observed that while at high level of contraction, root mean square (RMS) is an indicator of strength of contraction of the muscle, this relationship is not very strong when the muscle contraction is less than 50% maximum voluntary contraction. This work has established that MFL is a more reliable measure of strength of contraction compared to RMS, especially at low levels of contraction. This research work reports the use of fractal properties of sEMG to identify the small changes in strength of muscle contraction and the location of the active muscles. It is observed that fractal dimension (FD) of the signal is related with the properties of the muscle while maximum fractal length (MFL) is related to the strength of contraction of the associated muscle. The results show that classifying MFL and FD of a single channel sEMG from the forearm it is possible to accurately identify a set of finger and wrist flexion based actions even when the muscle activity is very weak. It is proposed that such a system could be used to control a prosthetic hand or for human computer interface.