Eric Da Silva's research while affiliated with Ryerson University and other places

Publications (15)

Article
Purpose: Dual-energy X-ray absorptiometry (DXA) is the gold standard technique to measure areal bone mineral density (aBMD) for the diagnosis of osteoporosis. Because DXA relies on the attenuation of photon to estimate aBMD, deposition of bone-seeking metallic elements such as strontium, lead and aluminum that differ in atomic numbers from calcium...
Article
Objective: Lanthanum (La) is commonly used in phosphate binders in the form of lanthanum carbonate in patients with end-stage kidney disease undergoing hemodialysis treatments. With this administration, there is the potential for La storage in the body with bone being the main site of concern. However, the long-term effects of residual La in the b...
Article
Objective: The calibration of in vivo x-ray fluorescence systems of bone strontium quantification, based on 125I excitation, is dependent on a coherent normalization procedure. Application of this procedure with the use of plaster of Paris (poP) as a phantom material requires the application of a coherent conversion factor (CCF) to make the calibr...
Article
Purpose:Bone quantity, as determined by the current gold standard, dual energy X-ray absorptiometry (DXA), through measured areal bone mineral density (aBMD), is subject to positive biases if bone strontium levels are high. This is of particular concern for populations administered strontium-based compounds for the treatment of osteoporosis. This s...
Poster
Gadolinium-based agents have been in clinical use as contrast agents for magnetic resonance imaging (MRI) scans and are recently being examined as radio-sensitizers to enhance therapeutic indices of radiation therapy treatment plans. Quantification of residual and potentially long-term storage of gadolinium is essential to our understanding of the...
Article
The current in vivo x-ray fluorescence spectrometry (IVXRF)-based method of bone strontium quantification is dependent on calibration against plaster of Paris (poP; ) calibrators/phantoms. Issues with the dissimilarity of the poP in comparison to bone mineral and the known issue with high levels of strontium contamination in commercial poP material...
Article
Plaster of Paris (poP, CaSO4•1/2H2O) is the standard phantom material used for the calibration of in vivo X-ray fluorescence (IVXRF)-based systems of bone metal quantification (i.e. bone strontium and lead). Calibration of IVXRF systems of bone metal quantification employs the use of a coherent normalization procedure which requires the application...
Chapter
The use of Raman spectroscopy for the study of the molecular order in triglycerides is explored, with emphasis placed on three key spectroscopic fingerprints: (i) the CH stretching region at 3000–2700 cm−1, (ii) the ester carbonyl (CO) stretching region at 1780–1700 cm−1, and the CC stretching region at ∼1200–1100 cm−1. Triglyceride polymorph and p...
Article
Trace elements, most notably aluminium and strontium, have been noted for their role in the development of secondary bone disorders in haemodialysis patients. Due to the large dosages of calcium required for the maintenance of dialysis patients, this study investigated whether the source of calcium chosen for supplementation, including the form of...
Article
This study applied wavelength-dispersive X-ray fluorescence spectrometry (WDXRF), with its high spectral resolution, to monitor the photographic process, tarnishing and restoration of pristine Daguerreotypes made in the traditional 19th century fashion. The elemental changes upon restoration via thiourea treatment, were evaluated and compared to a...
Article
High densities of white-tailed deer (Odocoileus virginianus) in the U.S.A. and Canada are reducing or preventing forest regeneration, and as a result, deer function as a keystone species in some sites. Management decisions about deer require reliable population density data, which are challenging to obtain at both regional and local scales. We test...
Article
Raman spectroscopy was used to distinguish the differences in the molecular organization of the alpha, beta' and beta polymorphs, as well as the liquid state, of tristearin with focus placed on the C=O, C-H and C-C Raman-active stretching regions. The ester carbonyl stretching region permitted polymorphic discrimination due to significant differenc...
Article
The conformational and thermodynamic behavior of five monoacid saturated triglycerides (TGs) before, during, and above the beta polymorph --> liquid phase transition was studied using Raman spectroscopy. The Raman ratio I[upsilon(s)(CH(2))]/I[upsilon(as)(CH(2))], used to identify intramolecular order about TG hydrocarbon chains, demonstrated that a...
Article
The use of an energy-dispersive X-ray fluorescence spectrometry (EDXRF) system equipped with an 125I source was validated for in vivo and ex vivo quantification of strontium in human teeth. The mean concentration of enamel strontium for an area with a high influx of immigration (Toronto, Ontario, Canada) is also reported. It was found that the mass...

Citations

... The same cylindrical hydroxyapatite (HAp) phantom with a concentration of 20 µg La g −1 HAp used in a previous publication was used for all experimental coherent normalization measurements (Nguyen et al 2017). This phantom was encased in a 0.13 cm thick polypropylene tube with a height and diameter of 10 cm and 2.7 cm, respectively. ...
... To prepare bare bone trabecular-mimicking phantoms with varying BMD values, HA samples were made in-house using the method developed by Da Silva et al. 42,43 The HA phantoms were prepared with a constant (Ca+Sr)/P mole ratio of 1.67. Strontium-substituted phantoms were prepared by mixing dry reagents CaHPO 4 · 2H 2 O (USP grade, Amresco, Solon, OH, USA) with Ca(OH) 2 (USP grade, Amresco, Solon, OH, USA) and Sr(OH) 2 ·8H 2 O (99% metals basis, Alfa Aesar, Ward Hill, MA, USA). ...
... Therefore, for more accurate Pb concentration measurements, future investigations might consider other bone substitute materials to produce the bare bone Pb calibration line data. A good bone phantom material could be the hyroxyapatite phantom solution of Da Silva et al (2013) which would increase the bone phantom density and allow Pb doping through the addition of the standard Pb solution. ...
... MDLs for the five phantom trials with each system were combined using Avg ± SDOM, where SDOM=StdDev/n 1/2 . Other work on in vivo XRF system calibration has used MDL=2σ y,exp /m where σ y,exp represents the uncertainty in the 0 ppm (blank) calibration phantom peak area y exp (background) and m is the slope of the calibration line (Arnold et al., 2002;Da Silva et al., 2008;Graham and O'Meara, 2004;Grinyer et al., 2007Grinyer et al., , 2005Studinski et al., 2006Studinski et al., , 2004. This equation can be obtained from the first term in Eq. (1) above. ...
... Our results provide a scientific understanding of the unique optical effects of these artworks and therefore, in addition to providing valuable insight for developing preservation protocols, can inspire additional approaches for color printing, where nanostructures are directly manufactured by light. and compared with the number of daguerreotypes reported to have been produced in the 19th century, only a relatively small number of plates have been examined beyond conventional optical microscopy with spectroscopic techniques, scanning electron microscopy (SEM), and other nanoscale imaging methods capable of examining and characterizing the nanostructures on their surface (6,(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47). Unfortunately, time and exposure to the elements have irreversibly altered 19th-century daguerreotype images, making it difficult to use them to characterize their properties. ...
... In Raman spectra, the ester carbonyl stretching region can provide an insight into the lipid phase organization (47,48). Triglycerides have three polymorphic forms in the solid-like ordered phase: a, b 0 , and b (49). ...
... We identified the number of preferred herbaceous species at each site, as well as the abundance of preferred herbs, determined by the total number of preferred species-quadrat combinations at each site. To examine browse impacts on herb height (Koh et al. 2010;Wilbur et al. 2017), we selected large-flowered trillium for additional information and analyses. For the sites where it was present, we calculated the trillium frequency, based on the frequency of presence in the 30 quadrats; we then determined trillium maximum height, by calculating the site mean of the tallest individual (if present) in each quadrat. ...
... The most important enteral sources are intestinal phosphate binders and other drugs with Al in their composition. The effectiveness of Al-based binders to prevent phosphate absorption led to their widespread utilization during the 1970s and 1980s [2,5,6]. However, evidence of the adverse effects of Al accumulation, such as arterial stiffness, osteomalacia, and encephalopathy, led to the contraindication of these drugs in patients undergoing hemodialysis [7,8], with the proposal of calcium (Ca)-based phosphate binders (carbonate or acetate) to combat hyperphosphatemia [2]. ...
... This melting temperature is closer to the published α form melting temperature of 55 • C, as measured using DSC (E. Da Silva, Bresson, & Rousseau, 2009), than to that of the β ′ form, which is around 65 • C (Oh et al. (2002)). This difference can be attributed to the different temperature control conditions of each measuring technique, which shifted the actual transition temperatures to higher values, as is evident in the differences between the melting temperatures of each polymorph measured using DSC and PLM. ...
... The intensity ratio between antisymmetric (aCH) and symmetric (sCH) stretching CH 2 (see Fig. 1) is known to be sensitive to the LPT [14,16]. To reveal the changes in the conformational state of lipids we investigated temperature dependencies for I aCH /I sCH ratio in the CH band of the lipid component. ...