Observation of Ground-level Enhancement Across Canada's Fixed Point Surveillance Network During the 20 January 2005 Solar Event.

This paper presents the count rate enhancement observed across Canada's Fixed Point Surveillance network during the solar event on 20 January 2005 and explores the feasibility and value of applying the Fixed Point Surveillance network's long-term and continuous observations for space weather monitoring. The count rate, recorded in the high-energy channel of RS250 sodium iodide detectors, reflects the detector's response to muonic and electromagnetic components of the cosmic ray shower. During the event peak time, simultaneous count rate increases have been observed across many Fixed Point Surveillance network stations at enhancements varying from 10% to 18%, 12- to 15-fold less than relative increases in neutron detector observations.

Development of a national cosmic-ray dose monitoring system with Health Canada's Fixed Point Surveillance network.

This work explores the application of Health Canada's Fixed Point Surveillance (FPS) network for cosmic ray monitoring and dose estimation purposes. This network is comprised of RS250 3 inch by 3 inch Sodium Iodide (NaI) spectroscopic dosimeters distributed throughout Canada. The RS250's high channel count rate responds to the electromagnetic and muonic components of cosmic ray shower. These count rates are used to infer cosmic ray doses throughout FPS locations. The derived dose was found to have an accuracy within 6.5% deviation relative to theoretical calculation. The solar cycle effect and meteorologically induced fluctuation can be realistically reflected in the estimated dose. This work may serve as a basis to enable the FPS network to monitor and report both terrestrial and cosmic radiation in quasi-real time.

Biomolecular diagnosis of human glioblastoma multiforme using Synchrotron mid-infrared spectromicroscopy.

Glioblastoma multiforme (GBM) is one of the most malignant human tumors, with a uniformly poor outcome. One obstacle in curing malignant brain tumors is the limitation of conventional light microscopy in detecting microscopic residual tumor in biopsy samples from the perimeter of the surgically resected tumor. We further refined the identification of GBM tumor tissue at the sub-cellular level, utilising the technique of Synchrotron, sourced mid-infrared (mid-IR) spectromicroscopy. Paired, thin (5 microm) cryosections of snap-frozen human GBM tumor samples removed at elective surgery were mounted on glass slides (hematoxylin and eosin-stained tissue section) and calcium fluoride (CaF2) windows (unstained tissue section for transmission spectromicroscopy), respectively. Concordance of tumor bearing areas identified in the stained section with the unstained IR tissue section was confirmed by the pathologist of the study. Compared with molecular signatures obtained from normal control brain tissue, unique spectroscopic patterns were detected in GBM tumor samples from 6 patients. The identifying features of GBM were: i) high protein-to-lipid ratios (amide I+II/CH2 symmetric stretch; amide I+II/CH2+CH3 symmetric and asymmetric stretch), and ii) considerable enhancement of the intensities of characteristic peaks at 2,957 and 2,871 cm(-1) representing CH3 asymmetric and symmetric stretch, respectively. Spectral data sets were subjected to Ward's algorithm for assignment to similar groups, and then subjected to hierarchical cluster analysis (HCA) by means of false color digital maps. False color images of 5 clusters obtained by HCA identified dominant clusters corresponding to tumor tissue. Corroboration of these findings in a larger number of GBM may allow for more precise identification of these and other types of brain tumors.