3,045 research outputs found
Knowledge transfer of microstrip detectors from particle to medical physics
This project is a demonstration of Knowledge Transfer. Knowledge in the fabrication, operation and application of radiation detectors originally developed for particle physics experiments has been exploited in diverse areas of research like medical applications. Microstrip detectors, commonplace in particle physics "trackers", have been evaluated as dosimeters for radiotherapy modalities. Hospital trails conducted under the supervision of clinical scientists demonstrated the viability of these detectors as dosimeters both in the quality assurance of linear accelerators and potentially in treatment planning verification. Important quantities of interest to the clinical scientist, like depth-dose distributions, output factors, off axis ratios etc. were measured with MV X-Rays from a clinical Linac and compared with the present day standard dosimeters. All results showed the performance of our novel dosimeter to be as good as or even better than that of the hospital dosimeters. Moreover the ability of our system for dose distribution measurements in real time was proven
CLEAR: a credible method to evaluate website archivability
Web archiving is crucial to ensure that cultural, scientific
and social heritage on the web remains accessible and usable
over time. A key aspect of the web archiving process is optimal data extraction from target websites. This procedure is
diïŹcult for such reasons as, website complexity, plethora of
underlying technologies and ultimately the open-ended nature of the web. The purpose of this work is to establish
the notion of Website Archivability (WA) and to introduce
the Credible Live Evaluation of Archive Readiness (CLEAR)
method to measure WA for any website. Website Archivability captures the core aspects of a website crucial in diagnosing whether it has the potentiality to be archived with completeness and accuracy. An appreciation of the archivability
of a web site should provide archivists with a valuable tool
when assessing the possibilities of archiving material and in-
uence web design professionals to consider the implications
of their design decisions on the likelihood could be archived.
A prototype application, archiveready.com, has been established to demonstrate the viabiity of the proposed method
for assessing Website Archivability
BlogForever D5.2: Implementation of Case Studies
This document presents the internal and external testing results for the BlogForever case studies. The evaluation of the BlogForever implementation process is tabulated under the most relevant themes and aspects obtained within the testing processes. The case studies provide relevant feedback for the sustainability of the platform in terms of potential usersâ needs and relevant information on the possible long term impact
BlogForever D5.3: User Questionnaires and Reports
This report presents the feedback gathered from third party users during the BlogForever Case Studies. Therefore, the research framework is defined and the case studies results are presented, followed by a summary of conclusions and remarks
Accelerating the convergence of path integral dynamics with a generalized Langevin equation
The quantum nature of nuclei plays an important role in the accurate
modelling of light atoms such as hydrogen, but it is often neglected in
simulations due to the high computational overhead involved. It has recently
been shown that zero-point energy effects can be included comparatively cheaply
in simulations of harmonic and quasi-harmonic systems by augmenting classical
molecular dynamics with a generalized Langevin equation (GLE). Here we describe
how a similar approach can be used to accelerate the convergence of path
integral (PI) molecular dynamics to the exact quantum mechanical result in more
strongly anharmonic systems exhibiting both zero point energy and tunnelling
effects. The resulting PI-GLE method is illustrated with applications to a
double-well tunnelling problem and to liquid water
Is Diffusion Tensor Imaging-Guided Radiotherapy the New State-of-the-Art? A Review of the Current Literature and Technical Insights
Despite the increasing precision of radiotherapy delivery, it is still frequently associated with neurological complications. This is in part due to damage to eloquent white matter (WM) tracts, which is made more likely by the fact they cannot be visualised on standard structural imaging. WM is additionally more vulnerable than grey matter to radiation damage. Primary brain malignancies also are known to spread along the WM. Diffusion tensor imaging (DTI) is the only in vivo method of delineating WM tracts. DTI is an imaging technique that models the direction of diffusion and therefore can infer the orientation of WM fibres. This review article evaluates the current evidence for using DTI to guide intracranial radiotherapy and whether it constitutes a new state-of-the-art technique. We provide a basic overview of DTI and its known applications in radiotherapy, which include using tractography to reduce the radiation dose to eloquent WM tracts and using DTI to detect or predict tumoural spread. We evaluate the evidence for DTI-guided radiotherapy in gliomas, metastatic disease, and benign conditions, finding that the strongest evidence is for its use in arteriovenous malformations. However, the evidence is weak in other conditions due to a lack of case-controlled trials
Quantification and correction of distortion in diffusion-weighted MRI at 1.5 and 3 T in a muscle-invasive bladder cancer phantom for radiotherapy planning
OBJECTIVE: Limited visibility of post-resection muscle-invasive bladder cancer (MIBC) on CT hinders radiotherapy dose escalation of the residual tumour. Diffusion-weighted MRI (DW-MRI) visualises areas of high tumour burden and is increasingly used within diagnosis and as a biomarker for cancer. DW-MRI could, therefore, facilitate dose escalation, potentially via dose-painting and/or accommodating response. However, the distortion inherent in DW-MRI could limit geometric accuracy. Therefore, this study aims to quantify DW-MRI distortion via imaging of a bladder phantom. METHODS: A phantom was designed to mimic MIBC and imaged using CT, DW-MRI and T2W-MRI. Fiducial marker locations were compared across modalities and publicly available software was assessed for correction of magnetic susceptibility-related distortion. RESULTS: Fiducial marker locations on CT and T2W-MRI agreed within 1.2âmm at 3 T and 1.8âmm at 1.5 T. The greatest discrepancy between CT and apparent diffusion coefficient (ADC) maps was 6.3âmm at 3 T, reducing to 1.8âmm when corrected for distortion. At 1.5 T, these values were 3.9âmm and 1.7âmm, respectively. CONCLUSIONS: Geometric distortion in DW-MRI of a model bladder was initially >6âmm at 3 T and >3âmm at 1.5 T; however, established correction methods reduced this to <2âmm in both cases. ADVANCES IN KNOWLEDGE: A phantom designed to mimic MIBC has been produced and used to show distortion in DW-MRI can be sufficiently mitigated for incorporation into the radiotherapy pathway. Further investigation is therefore warranted to enable individually adaptive image-guided radiotherapy of MIBC based upon DW-MRI
EFFECTS OF A 10 WEEK TRAINING PROGRAM ON PHYSICAL CONDITIONING AND INSTEP KICK KINEMATICS IN SOCCER
The instep kick is the kick of choice in soccer scoring and passing over medium to long distances. Its success depends on many factors including the strength of the muscles responsible for the actions of the (kicking lower) extremity, the rate of muscle force production, the synchronization and energy transfer between lower extremity segments (Plagenhoef, 1971), the linear approach velocity (Opavsky, 1988) and approach angle (Isokawa and Less, 1988), and the ability of muscle to utilize effectively the stretch/shorten cycle (BOhrle, 1985). Ultimately, on a given kick, the velocity of the kicking foot and the point of (foot) force application on the ball determine the trajectory characteristics of the ball. Other factors such as flexibility and aerobic/anaerobic capacities also determine the ability of players to successfully perform in a game. The purpose of this study was to study the effects of a 10 week training program on selected physical conditioning and instep kick kinematic parameters in soccer
Efficient stochastic thermostatting of path integral molecular dynamics
The path integral molecular dynamics (PIMD) method provides a convenient way
to compute the quantum mechanical structural and thermodynamic properties of
condensed phase systems at the expense of introducing an additional set of
high-frequency normal modes on top of the physical vibrations of the system.
Efficiently sampling such a wide range of frequencies provides a considerable
thermostatting challenge. Here we introduce a simple stochastic path integral
Langevin equation (PILE) thermostat which exploits an analytic knowledge of the
free path integral normal mode frequencies. We also apply a recently-developed
colored-noise thermostat based on a generalized Langevin equation (GLE), which
automatically achieves a similar, frequency-optimized sampling. The sampling
efficiencies of these thermostats are compared with that of the more
conventional Nos\'e-Hoover chain (NHC) thermostat for a number of physically
relevant properties of the liquid water and hydrogen-in-palladium systems. In
nearly every case, the new PILE thermostat is found to perform just as well as
the NHC thermostat while allowing for a computationally more efficient
implementation. The GLE thermostat also proves to be very robust delivering a
near-optimum sampling efficiency in all of the cases considered. We suspect
that these simple stochastic thermostats will therefore find useful application
in many future PIMD simulations.Comment: Accepted for publication on JC
CHANGES OF FORCE AND SPEED CHARACTERISTICS IN MALES AND FEMALES EIGHT TO FIFTY YEARS OLD
The purpose of this study was to determine changes of force and speed characteristics in male and female subjects from eight to 50 years old. Four hundred and eighteen sedentary subjects grouped by age from eight to 50 years old were tested for several force and speed indicators. One-way ANOVA revealed that the majority (four out of six) of force and speed characteristics showed significant increases in subjects up to 30 years of age and subsequent significant decreases. The remaining two indicators showed continuous decline throughout the tested lifespan. It is suggested that these results may be used as a criterion which may assist in promoting physical activity and sport beyond the age of 30 years
- âŠ