Real-time MR tumour tracking and beam delivery using a linac-MR system

Yun, Jihyun

Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2H7

ABSTRACT

Radiation therapy is a proven strategy in cancer treatment. The ultimate goal of

radiotherapy is to focus radiation beam only on tumours to destroy them without unduly harming the surrounding healthy tissues. Current radiotherapy technology has very little problem in the safe delivery of radiation to non-moving tumours such as brain tumours.

However, treating mobile tumours (e.g. lung) with radiation is still a difficult task, mainly

because we have no means of imaging the tumour while the beam is on. This problem could be solved by a linac-MR system invented at the Cross Cancer Institute in 2008, which could allow us to image tumors in real-time.

By using this feature, the objective of this project is to develop methods to 1) track the position and shape changes of the tumour in real-time, and 2) deliver the radiation beam accordingly, in order to minimize normal tissue irradiation while treating mobile tumours.

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Chances of N saturation in boreal forest ecosystems in Athabasca oil sands region, Alberta, Canada

Kangho JUNG* and Scott X. CHANG

Department of Agricultural, Life & Environmental science, University of Alberta, Edmonton, Alberta, Canada T6G 2H7

ABSTRACT

Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3

Boreal forest ecosystems in the Athabasca oil sands region (AOSR) have been exposed to significant N and S deposition longer than 40 years. The N deposition in AOSR has been increased, which made the long-term effect of N deposition concerned. The changes in N pool and nutrient loss by N and S deposition was simulated by this study with four treatments; control, N application, S application, and N+S application from 2006 and 2009. N application induced increments of tree growth without luxury uptake (p<0.05) while understory accumulated N without any increase of aboveground biomass. No significant difference of soil microbial biomass C and N was found between treatments. Ammonium and nitrate concentrations in forest floor and surface mineral soil increased after N application (p<0.05) while no difference of inorganic N in soils was found between treatments after the late summer. Our results show that the N deposition increased N availability and mobility and N saturation in boreal forests remains a concern in AOSR though it may not happen in the near future.

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The Effect of Surface Elasticity on an Elastic Solid with a Crack: Complete Solution

C. I. Kim ¹, P. Schiavone ², C-Q. Ru ³

Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 2G8, Canada

ABSTRACT

The analysis of stresses in the general region of a crack tip is of fundamental importance in the understanding of failure and in the general deformation analysis of engineering materials. In macroscopic models, the stresses at the crack tip are found to be infinite reflecting the fact that the crack front is usually taken to be perfectly sharp. In fact, an infinitely sharp crack in a continuum is a mathematical abstraction since, in reality, most crack tips are, in fact, blunt, with a radius of convergence of the order compatible with the nanoscale. This suggests that a more accurate analysis of the region in the vicinity of a crack tip can be achieved at the nanoscale. In the context of a continuum model this means the incorporation of surface effects into the model of deformation.

In the presentation, we consider general deformations of a linearly elastic solid where a single crack is present but, perhaps more significantly, when surface effects are incorporated in the mechanics of the crack faces. The surface effects lead to a more accurate description of finite stress at the crack

 

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Effects of ER stress, PERK and eIF2-α on regulation of polycystin-2

Jungwoo Yang, Zuocheng wang, Carlos Lara, and Xing-Zhen Chen

Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) is associated with numerous

cellular abnormalities such as cell over-proliferation and apoptosis. Mutations in

polycystin-2 (PC2) account for about 10% of ADPKD cases. We recently reported that

PC2 down-regulates cell proliferation and protein synthesis through promoting the

phosphorylation of eukaryotic initiation factor 2-α (eIF2- α) by pancreatic ER eIF2a kinase (PERK). ER stress is known to be induced by disruptions of ER homeostasis, and leads to the acumulation of unfolded protein in ER lumen. Intracellular signal trasduction pathway induced by accumulated unfolded protein in the ER lumen is the unfolded protein response (UPR). We found that PC2 is up-regulated under ER stress. And we showed that PC2 expression is re-regulated by PERK kinase activity. These data together indicate that ER stress up-regulates PC2 expression through increased PERK activity. We are currently examining whether eIF2α activity is sufficient to up-regulate PC2 expression, using eIF2α over-expression, knockdown and induction of eIF2α activity by other eIF2α kinases. These studies together will shed light on how PC2 is regulated and its functional roles in the ER.

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A population-based comparison of injuries among farm children

to non-farm children in Alberta, 1998-2009

Kyungsu Kim

Department of Agricultural, Life & Environmental science, University of Alberta, Edmonton, Alberta, Canada T6G 2H7

ABSTRACT

Agriculture continues to be one of the most dangerous occupations in Canada. Farm hazards are extended to not only farm workers but farm children. Prior studies have focused on agricultural injuries among children, and all causes of injuries for farm children and comparison to other groups of children have not been studied in North America.

The proposed study will examine whether farm children under 20 years of age are at greater risk for injuries than non-farm children of that age in Alberta from 1998-2009.Injury incidence will be derived from the linkage of various administrative health databases: death certificates and records of hospitals, emergency departments, and physician visits.

This study will provide an accurate and comprehensive understanding of injuries for farm children and will help inform injury prevention strategies and safety standards for farm children.

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Responses of saproxylic beetles to aggregated retention patches in boreal white spruce stands

Lee, Seung-Il

Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3

ABSTRACT

Saproxylic beetles (i.e. beetles that depend on dead or dying wood during some part of their life cycle) are a diverse group of organisms that are well known to be threatened by traditional forestry activities. Green tree retention has been proposed and developed as a way of conserving biodiversity for the ecological sustainability. To understand the role of aggregated patches in relation to effects of sizes and surrounded matrices on saproxylic beetle assemblages, we compared beetles among two sizes of aggregated retention patches (0.20 and 0.46 ha) within backgrounds of different harvest intensity at the EMEND (Ecosystem Management Emulating Natural Disturbance) site. Window traps were deployed on girdled trees, snags and live trees in patches and surrounding matrices. Emergence traps were also placed on logs of two decay classes (DC 2 and DC 4) in the same patches. The data will provide information tools needed to develop effective conservation strategies.

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Synthesis of the natural product travesianal

Yonghoon Kwon

Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7

ABSTRACT

I have been carrying out the chemical synthesis of the natural product travesianal.

Traversianal, a tricyclic diterpenoid fungal metabolite, has shown distinct toxicity to

various invertebrates. This activity suggests further biological value in that similar natural products have shown anticancer activities. It is highly challenging to synthesize

traversianal since it has a complex structure - a 5-8-5 ring skeleton and six stereogenic

centers. Methodology created by our group has been used to make the core ring skeleton.

Particularly, a photochemical [4+4]-photocycloaddition reaction has been used to direct

assemble the entire carbon skeleton. The core is synthesized by UV light, which is very

economical since no catalysts or reagents are consumed. To synthesize traversianal more efficiently are examined variations of the methodology. I believe the variations would lead faster and more economical synthesis, while ultimately providing scientific

knowledge of the photochemical reactions.