•Estimating arrival times of extensional and flexural wave modes is of importance.•A method is needed to quickly and reliably make this estimation on large data sets.•Algorithms to perform this ...estimation are developed and presented.•MATLAB scripts including relevant examples are developed and made available online.
In health monitoring applications of composite materials, the health state of specimens is often evaluated using naturally occurring and simulated Acoustic Emission stress waves. For such applications, identifying the arrival times of the extensional and flexural wave modes from acquired signals is a crucial step, and must be performed reliably and potentially on large sets of signals. This article proposes using the wavelet decomposition of a signal to develop a fast, algorithmic and automated approach to estimate the arrival times of the extensional and flexural wave modes. Algorithms are developed that estimate the two arrival times using wavelet decomposition data, and which can be employed to consistently and reliably identify the arrival times from large sets of signals iteratively. MATLAB scripts to automatically execute the algorithms are also developed, and are made available online.
In 2012, Defence Research and Development Canada, in partnership with a number of other Canadian and International organizations, led a series of three field trials designed to simulate a ...Radiological Dispersal Device (RDD). These trials, known as the Full-Scale RDD (FSRDD) Field Trials, involved the explosive dispersal of a short-lived radioactive tracer ((140)La, t1/2 = 40.293 h). The FSRDD Field Trials required a significant effort in their planning, preparation, and execution to ensure that they were carried out in a safe, efficient manner and that the scientific goals of the trials were met. The discussion presented here details the planning and execution of the trials, outlines the relevant radiation safety aspects, provides a summary of the source term and atmospheric conditions for the three dispersal events, and provides an overview of the measurements that were made to track the plumes and deposition patterns.
•Quality synthesis of Sr3Gd(1−x)PO43:xEu3+ phosphors for LED application.•The phosphor's life time achieved at 3.33 ms.•CIE colour indicating good colour purity.
A series of Sr3Gd(1−x)PO43:xEu3+ ...phosphors were synthesized using the standard high temperature solid-state reaction method. The photoluminescence investigation is utilized to reveal the excitation and emission spectra of the as-synthesized phosphors. Photoluminescence properties show that the phosphor can be efficiently excited by ultraviolet visible light in the region from 300 to 420 nm, and it exhibits red emission (612 nm) corresponding to 5D0 → 7F2 transition and there is no concentration quenching is observed. Relying on the diffuse reflection spectra, the band gap was estimated to be about 3.8 eV. The phosphor's life time value was 3.33 ms. As-synthesized phosphor has a significant CIE value, indicating good colour purity. These findings suggest that the Sr3Gd(1−x)PO43: xEu3+ phosphor for near-ultraviolet white light-emitting LEDs.
Gallium-68 is an important radionuclide for positron emission tomography (PET) with steadily increasing applications of 68Ga-based radiopharmaceuticals for clinical use. Current 68Ga sources are ...primarily 68Ge/68Ga-generators, along with successful attempts of 68Ga production using a cyclotron. This study evaluated cyclotron 68Ga production and automated separation using expeditiously manufactured solid targets, demonstrates an order of magnitude improvement in yield compared to 68Ge/68Ga generators, and presents a convenient alternative to existing cyclotron production processes. A comparison of radiolabeling and preclinical PET imaging was performed with both cyclotron and generator produced 68Ga.
100 mg enriched 68Zn (99.3% 68Zn, 0.48% 67Zn, 0.1% 66Zn) pellets pressed on silver discs were bombarded for 20–75 min using 12.5 MeV proton beam energies and 10–30 μA currents. 68Ga was separated using an automated TRASIS AllinOne synthesizer employing AG 50W-X8 and UTEVA resins. Post-separation recovery of the 68Zn by electrolysis yielded 76.7 ± 4.3%. Radionuclidic purity of cyclotron-produced 68Ga was investigated with gamma spectroscopy using a HPGe-detector. Radiolabeling was investigated using the macrocyclic chelator DOTA and the bombesin-derived peptide NOTA-BBN2. PET imaging was performed using 68GaGa-NOTA-BBN2 in a PC3 xenograft model.
600 μA·min fresh and recycled quadruplet 68Zn target irradiations (n = 8) at 12.5 MeV and 30 μA yielded 13.9 ± 1.0 GBq 68Ga; 2200 μA·min irradiations (n = 3) yielded 37.5 ± 1.9 GBq 68Ga. HPGe analysis showed EOB 0.0074% and 0.0084% of total activity of 66Ga and 67Ga, respectively. Metal impurities were 0.06 ± 0.03 μg/GBq Zn, 0.13 ± 0.007 μg/GBq Fe, and 0.02 ± 0.01 μg/GBq Al for cyclotron 68Ga. Cyclotron and 68Ge/68Ga generator 68Ga respective DOTA and NOTA-BBN2 labeling incorporations were 99.4 ± 0.0% and 99.3 ± 0.2%, and 90.4 ± 1.5% and 93.0 ± 3.6% determined by radio-thin layer chromatography (radio-TLC). Preclinical PET imaging comparison between generator and cyclotron produced 68Ga showed identical radiotracer tumor uptake and biodistribution profiles in PC3 tumor bearing mice.
Cyclotron 68Ga production provides highly scalable production with equivalent or superior quality 68Ga to a 68Ge/68Ga generator, while providing identical biodistribution and tumor uptake profiles. Our described targetry is simpler and more cost-effective than existing liquid and solid targetry, enabling a turnkey production system for multi-facility distribution of cyclotron produced 68Ga. The manufacturing simplicity described has potential applications for producing other radiometals such as 44Sc.
Our cost-effective method of solid target 68Ga production can enhance 68Ga production capabilities to meet the high demand for 68Ga-radiopharmaceuticals for research and clinical use.
We investigated elemental strontium and/or bisphosphonate drug incorporation upon the compositional and biomechanical properties of vertebral bone, in a rat model of Osteoporosis secondary to ...ovariectomy.
Six month old female rats were ovariectomized (OVX) and divided into untreated OVX-Vehicle, OVX-RIS (Risedronate bisphosphonate BP treated), OVX-SrR (Strontium Ranelate Protos® treated), combination OVX-RIS+SrR, and sham-operated controls. After 16 weeks of treatment, rats were euthanized and lumbar vertebra were dissected. Micro-Computed Tomography (micro-CT), Electron Probe Micro-Analysis (EPMA), mechanical testing in compression and nano-indentation testing were then undertaken to evaluate bone morphometry, elemental composition, material properties and strength.
Bone Volume was significantly reduced in the OVX-Vehicle (133±10 mm(3)) compared with OVX-RIS (169±22 mm(3)), OVX-SrR (145±2 mm(3)), and OVX-RIS+SrR (172±8 mm(3)). EPMA mapped elemental Sr deposition to the periosteal surface of cortical bone (50-100 µm thick), endosteal trabecular surfaces (20 µm thick), as well as to both vertebral growth plates. The atomic ratios of (Ca+Sr)/P were significantly reduced with SrR treatment (2.4%-6.6%), indicating Sr incorporation into bone mineral. No significant differences were measured in vertebral bone reduced modulus by nano-indentation. Conversely, all BP-dosed groups had significantly increased structural bone strength.
Thus, we conclude that BP drugs dominate the conservation of trabecular geometry and structural strength in OP rats, whereas Sr drugs likely influence bone volume and material composition locally.
Four pristine specimens of the Tagish Lake C2 chondrite meteorite were previously determined through mineralogy, petrology, and organic chemistry to have been affected by aqueous alteration in the ...order (from least to most altered) TL5b < TL11h < TL11i, and TL11v as a mixture of the other specimens (Herd et al. ; Blinova et al. ). Here, we report the whole‐rock data for a total of 65 elements for the same four Tagish Lake samples as determined by ICP‐MS and ICP‐AES (utilizing the Parr bomb digestion method on small samples, approximately 50 mg), and by INAA. Our data demonstrate that the determined aqueous alteration sequence has a positive correlation with trace elements, such as K and Br that are mobile during aqueous alteration, which appear to be controlled by an increase of phyllosilicates from least to most altered samples. Yet, the homogeneity of other elements suggests that elemental mass transfer occurred on a localized scale and aqueous alteration was isochemical for these elements, similar to other primitive carbonaceous chondrites. By plotting data from three samples (TL5b, TL11h, and TL11i) on a Zn/Mn versus Sc/Mn diagram, we also confirm that the Tagish Lake meteorite is not a simple mixture of CI and CM material.
A new Eu
-substituted CsK
YVO
glaserite-type orthovanadate phosphor was synthesized by the conventional high temperature solid-state reaction method. The phase purity was confirmed by powder X-ray ...diffraction study and it reveals that all the compositions crystallize in the hexagonal structure. The morphology and elemental composition were measured by FE-SEM with Energy Dispersive Analysis Of X Rays (EDAX). The band gap is determined by diffuse reflectance spectra. The self-activated luminescence of the host and Eu
-substituted luminescence behaviours were studied in detail by photoluminescence spectra. The host CsK
YVO
shows green emission, whereas the Eu
-substituted compositions show red emission. Effect of Eu
concentrations on the photoluminescence behaviour were also been studied. The Eu
-doped samples show not only several sharp emission lines but also a broad emission band due to presence of the VO
in the host, which clearly indicates that there is incomplete energy transfer from (VO
) charge transfer band to Eu
The life time of the phosphors also been studied. The Commission Internationale de l'Eclairage (CIE) chromaticity colour coordinates were calculated and it is very much closer to the National Television Standard Committee (NTSC) standards. These investigations evidently reveal that the self-activated and Eu
-activated phosphors show a great potential applications as a red phosphor for solid-state lighting includes white light-emitting diodes (wLEDs).
We investigated whether the recent implementation of the regulatory requirements for the entry to the Canadian market of natural products has resulted in improved quality of the available glucosamine ...products.
Eleven available products, of which 8 had been tested in 2002 (7 had contained substantially lower than the label claim of the active ingredient), and a European pharmaceutical grade tablet were assayed for their glucosamine content. The potassium and sodium contents of the products were also tested.
Nine of the 11 Canadian products and the European tablet had more than 91% of the label claim of the active ingredient, hence, met the criterion. Two products contained 71 and 78% label claim. The electrolyte contents were very variable but constituted only a small fraction of the daily requirements.
Most tested glucosamine products passed the Health Canada requirements. This improvement is likely due to the publicity regarding the low quality of the products in the past and also a result, at least in part, of the introduction of the new regulatory requirements. The sub-standard quality of a few tested products is still of concern.
Theranostic isotope pairs have gained recent clinical interest because they can be labeled to the same tracer and applied for diagnostic and therapeutic purposes. The goals of this study were to ...investigate cyclotron production of clinically relevant
La activities using natural and isotopically enriched barium target material, compare fundamental PET phantom imaging characteristics of
La with those of common PET radionuclides, and demonstrate in vivo preclinical PET tumor imaging using
La-PSMA-I&T.
La was produced on a 24-MeV cyclotron using an aluminum-indium sealed target with 150-200 mg of isotopically enriched
BaCO
,
BaCO
, and
Ba metal. A synthesis unit performed barium/lanthanum separation. DOTA, PSMA-I&T, and macropa were radiolabeled with
La. Derenzo and National Electrical Manufacturers Association phantom imaging was performed with
La,
La, and
Zr and compared with
F,
Ga,
Sc, and
Cu. In vivo preclinical imaging was performed with
La-PSMA-I&T on LNCaP tumor-bearing mice.
Proton irradiations for 100 µA·min at 23.3 MeV yielded 214 ± 7 MBq of
La and 28 ± 1 MBq of
La using
BaCO
, 59 ± 2 MBq of
La and 35 ± 1 MBq of
La using
BaCO
, and 81 ± 3 MBq of
La and 48 ± 1 MBq of
La using
Ba metal. At 11.9 MeV,
La yields were 81 ± 2 MBq, 6.8 ± 0.4 MBq, and 9.9 ± 0.5 MBq for
BaCO
,
BaCO
, and
Ba metal. BaCO
target material recovery was 95.4% ± 1.7%. National Electrical Manufacturers Association and Derenzo phantom imaging demonstrated that
La PET spatial resolution and scanner recovery coefficients were superior to those of
Ga and
La and comparable to those of
Zr. The apparent molar activity was 130 ± 15 GBq/µmol with DOTA, 73 ± 18 GBq/µmol with PSMA-I&T, and 206 ± 31 GBq/µmol with macropa. Preclinical PET imaging with
La-PSMA-I&T provided high-resolution tumor visualization with an SUV of 0.97 ± 0.17 at 60 min.
With high-yield
La cyclotron production, recovery of BaCO
target material, and fundamental imaging characteristics superior to those of
Ga and
La,
La represents a promising radiometal candidate to provide high-resolution PET imaging as a PET/α-therapy theranostic pair with
Ac or as a PET/Auger electron therapy theranostic pair with
La.
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