359 research outputs found
Institutional experience with a rotational total skin electron irradiation (RTSEI) technique—A three decade review (1981–2012)
AbstractTotal skin electron irradiation (TSEI) for patients with cutaneous lymphomas is technically challenging, and numerous approaches have been developed to overcome the many field matching problems associated with such a large and complex treatment volume. Since 1981 we have delivered TSEI using a rotational total skin electron irradiation (RTSEI) technique in conjunction with patch, treat and boost fields in order to provide complete skin and dose coverage. Initially we used a 6MeV electron beam at an extended source-skin distance (SSD) on a modified linear accelerator. More recently we began using a high dose rate electron mode on a commercially available linear accelerator. The RTSEI technique allows the delivery of a seamless surface dose to the majority of the patient's skin surface in a single treatment. In this review paper we present our three-decade experience with the technical development, dosimetry, treatment delivery and clinical outcomes of our RTSEI technique
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Heat Pump Water Heater Technology Assessment Based on Laboratory Research and Energy Simulation Models: Preprint
This paper explores the laboratory performance of five integrated Heat Pump Water Heaters (HPWHs) across a wide range of operating conditions representative of US climate regions. Laboratory results demonstrate the efficiency of this technology under most of the conditions tested and show that differences in control schemes and design features impact the performance of the individual units. These results were used to understand current model limitations, and then to bracket the energy savings potential for HPWH technology in various US climate regions. Simulation results show that HPWHs are expected to provide significant energy savings in many climate zones when compared to other types of water heaters (up to 64%, including impact on HVAC systems)
Institutional experience with a rotational total skin electron irradiation (RTSEI) technique—A three decade review (1981–2012)
Total skin electron irradiation (TSEI) for patients with cutaneous lymphomas is technically challenging, and numerous approaches have been developed to overcome the many field matching problems associated with such a large and complex treatment volume. Since 1981 we have delivered TSEI using a rotational total skin electron irradiation (RTSEI) technique in conjunction with patch, treat and boost fields in order to provide complete skin and dose coverage. Initially we used a 6[[ce:hsp sp="0.25"/]]MeV electron beam at an extended source-skin distance (SSD) on a modified linear accelerator. More recently we began using a high dose rate electron mode on a commercially available linear accelerator. The RTSEI technique allows the delivery of a seamless surface dose to the majority of the patient's skin surface in a single treatment. In this review paper we present our three-decade experience with the technical development, dosimetry, treatment delivery and clinical outcomes of our RTSEI technique
Fostering clinical reasoning in physiotherapy: Comparing the effects of concept map study and concept map completion after example study in novice and advanced learners
Background: Health profession learners can foster clinical reasoning by studying worked examples presenting fully worked out solutions to a clinical problem. It is possible to improve the learning effect of these worked examples by combining them with other learning activities based on con
Implementing a case management intervention for frequent users of the emergency department (I-CaM): An effectiveness-implementation hybrid trial study protocol
Background: ED overcrowding represents a significant public health problem in developed countries. Frequent users of the emergency departments (FUEDs; reporting 5 or more ED visits in the past year) are often affected by medical, psychological, social, and substance use problems and account for a disproportionately high number of ED visits. Past research indicates that case management (CM) interventions are a promising way to reduce ED overcrowding and improve FUEDs' quality of life. There is, however, very limited knowledge about how to disseminate and implement this intervention on a large scale to diverse clinical settings, including community hospitals and non-academic centers. This paper describes the protocol of a research project aiming to implement a CM intervention tailored to FUEDs in the public hospitals with ED in the French-speaking region of Switzerland and evaluate both the implementation process and effectiveness of the CM intervention. Methods: This research project uses a hybrid study design assessing both implementation and clinical outcomes. The implementation part of the study uses mixed methods a) to describe quantitatively and qualitatively factors that influence the implementation process, and b) to examine implementation effectiveness. The clinical part of the study uses a within-subject design (pre-post intervention) to evaluate participants' trajectories on clinical variables (e.g., quality of life, ED use) after receiving the CM intervention. We designed the study based on two implementation science frameworks. The Generic Implementation Framework guided the overall research protocol design, whereas the RE-AIM (reach, efficacy, adoption, implementation and maintenance) framework guided the implementation and effectiveness evaluations. Discussion: This research project will contribute to implementation science by providing key insights into the processes of implementing CM into broader practice. This research project is also likely to have both clinical and public health implications. Trial registration: NCT03641274, Registered 20 August 2018
Electronic redistribution around oxygen atoms in silicate melts by ab initio molecular dynamics simulation
The structure around oxygen atoms of four silicate liquids (silica, rhyolite,
a model basalt and enstatite) is evaluated by ab initio molecular dynamics
simulation. Thanks to the use of maximally localized Wannier orbitals to
represent the electronic ground state of the simulated system, one is able to
quantify the redistribution of electronic density around oxygen atoms as a
function of the cationic environment and melt composition. It is shown that the
structure of the melt in the immediate vicinity of the oxygen atoms modulates
the distribution of the Wannier orbitals associated with oxygen atoms. In
particular the evaluation of the distances between the oxygen-core and the
orbital Wannier centers and their evolution with the nature of the cation
indicates that the Al-O bond in silicate melts is certainly less covalent than
the Si-O bond while for the series Mg-O, Ca-O, Na-O and K-O the covalent
character of the M-O bond diminishes rapidly to the benefit of the ionic
character. Furthermore it is found that the distribution of the oxygen dipole
moment coming from the electronic polarization is only weakly dependent on the
melt composition, a finding which could explain why some empirical force fields
can exhibit a high degree of transferability with melt composition.Comment: 27 pages, 7 figures. To be published in Journal of Non-Crystalline
Solid
Patterns of multimorbidity in working Australians
Background: Multimorbidity is becoming more prevalent. Previously-used methods of assessing multimorbidity relied on counting the number of health conditions, often in relation to an index condition (comorbidity), or grouping conditions based on body or organ systems. Recent refinements in statistical approaches have resulted in improved methods to capture patterns of multimorbidity, allowing for the identification of nonrandomly occurring clusters of multimorbid health conditions. This paper aims to identify nonrandom clusters of multimorbidity.Methods: The Australian Work Outcomes Research Cost-benefit (WORC) study cross-sectional screening dataset (approximately 78,000 working Australians) was used to explore patterns of multimorbidity. Exploratory factor analysis was used to identify nonrandomly occurring clusters of multimorbid health conditions.Results: Six clinically-meaningful groups of multimorbid health conditions were identified. These were: factor 1: arthritis, osteoporosis, other chronic pain, bladder problems, and irritable bowel; factor 2: asthma, chronic obstructive pulmonary disease, and allergies; factor 3: back/neck pain, migraine, other chronic pain, and arthritis; factor 4: high blood pressure, high cholesterol, obesity, diabetes, and fatigue; factor 5: cardiovascular disease, diabetes, fatigue, high blood pressure, high cholesterol, and arthritis; and factor 6: irritable bowel, ulcer, heartburn, and other chronic pain. These clusters do not fall neatly into organ or body systems, and some conditions appear in more than one cluster.Conclusions: Considerably more research is needed with large population-based datasets and a comprehensive set of reliable health diagnoses to better understand the complex nature and composition of multimorbid health conditions
Clustering of galaxies around radio quasars at 0.5 < z < 0.8
We have observed the galaxy environments around a sample of 21 radio-loud,
steep-spectrum quasars at 0.5<z<0.82, spanning several orders of magnitude in
radio luminosity. The observations also include background control fields used
to obtain the excess number of galaxies in each quasar field. The galaxy excess
was quantified using the spatial galaxy-quasar correlation amplitude, B_gq, and
an Abell-type measurement, N_0.5 (Hill & Lilly 1991). A few quasars are found
in relatively rich clusters, but on average, they seem to prefer galaxy groups
or clusters of approximately Abell class 0. We have combined our sample with
literature samples extending down to z=0.2 and covering the same range in radio
luminosity. By using Spearman statistic to disentangle redshift and luminosity
dependences, we detect a weak, but significant, positive correlation between
the richness of the quasar environment and the quasar's radio luminosity.
However, we do not find any epoch dependence in B_gq, as has previously been
reported for radio quasars and galaxies. We discuss the radio
luminosity-cluster richness link and possible explanations for the weak
correlation that is seen.Comment: 18 pages, 9 figures, submitted to MNRA
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