canadian light source

We report Mo K- and LIII -edge X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) data collected for 15 molybdenum minerals and compounds sourced from museum collections, mineral dealers, and chemical suppliers. The samples were finely ground and analyzed at the Canadian Light Source synchrotron (Saskatoon, Canada). The LIII -edge XAS data were collected in fluorescence and total electron yield mode, while the K-edge XAS data were collected in transmission and fluorescence modes. Molybdenum LIII -edge spectra cover the X-ray absorption near edge structure (XANES) region and Mo K-edge spectra cover the extended X-ray absorption fine structure (EXAFS) region...

PURPOSE: Multiple-image radiography (MIR) is an analyzer-based synchrotron X-ray imaging approach capable of dissociating absorption, refraction, and scattering components of X-ray interaction with the material. It generates additional image contrast mechanisms (besides absorption), especially in the case of soft tissues, while minimizing absorbed radiation dose. Our goal is to develop a contrast agent for MIR using ultrasound microbubbles by carrying out a systematic assessment of size, shell material, and concentration...

BACKGROUND: Medium cut-off (MCO) membranes enhance large middle-molecule clearance while selectively retaining molecules >45 000 Da. OBJECTIVES: We undertook a systematic review and meta-analysis comparing the effects of MCO versus high-flux membranes on biomarkers. METHODS: We searched MEDLINE, Embase, CINAHL, Cochrane Library, and Web of Science from January 2015 to July 2020, and gray literature sources from 2017. We included randomized (RS) and nonrandomized studies (NRS) comparing MCO and high-flux membranes in adults (>18 years) receiving maintenance hemodialysis...

Eukaryotic pathogens including fungi and enteroparasites infect humans, animals and plants. As integrators of landscape catchment, lakes can reflect and record biological and geochemical events or anthropogenic changes and provide useful knowledge to formulate public health, food security and water policies to manage and prevent diseases. In this context, potentially pathogenic fungi and parasites were sampled using 18S rRNA gene amplicon sequencing in 382 lakes displaying a broad range of sizes and human impact on the watershed in 10 ecozones across Canada...

We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a variable fluorescence demonstrated relatively low photochemical efficiency over most of the cruise-track, with the exception of localized regions within Barrow Strait, where there was increased vertical mixing and proximity to land-based nutrient sources...

Gaining an in-depth understanding of the characteristics and dynamics of ultrasound (US)--generated bubbles is crucial to effectively remediate membrane fouling. The goal of present study is to conduct in-situ visualization of US-generated microbubbles in water to examine the influence of US frequency on the dynamics of microbubbles. This study utilized synchrotron in-line phase contrast imaging (In-line PCI) available at the biomedical imaging and therapy (BMIT) beamlines at the Canadian Light Source (CLS) to enhance the contrast of liquid/air interfaces at different US frequencies of 20, 28 and 40 KHz at 60 Watts...

BACKGROUND: In the 1920s, eight of nine Canadian provinces legalized alcohol sales, ending prohibition in favor of government control. Much has been written about the rise and fall of Prohibition in North America, but there is little work examining these events in the light of current drug policy debates. This paper attempts to fill some of these gaps. METHODS: The aims of this paper are primarily exploratory and descriptive. Following a literature review, it draws from secondary and some primary sources to explore the debate around ending alcohol prohibition (i...

Dissolved organic matter (DOM) is a ubiquitous component of aquatic systems, impacting aquatic health and drinking water quality. These impacts depend on the mixture of organic molecules that comprise DOM. Changing climates are altering both the amount and character of DOM being transported from the terrestrial system into adjacent surface waters, yet DOM composition is not monitored as often as overall concentration. Many DOM characterization methods exist, confounding comparison of DOM composition across different studies...

A new diffraction beamline for materials science has been built at the Canadian Light Source synchrotron. The X-ray source is an in-vacuum wiggler with a 2.5 T peak magnetic field at 5.2 mm gap. The optical configuration includes a toroidal mirror, a single side-bounce Bragg monochromator, and a cylindrical mirror, producing a sub-150 µm vertical × 500 µm horizontal focused beam with a photon energy range of 7-22 keV and a flux of 1012 photons per second at the sample position. Three endstations are currently open to general users, and the techniques available include high-resolution powder diffraction, small molecule crystallography, X-ray reflectivity, in situ rapid thermal annealing, and SAXS/WAXS...

A discrepancy between theoretical and experimental values of the rotational barrier in benzaldehyde has been observed, which was attributed to inaccurate experimental results in part. Here, we report results on the -CHO torsion of benzaldehyde (C6 H5 CHO) based on a high resolution spectroscopic investigation in the far-infrared range in an effort to remove the experimental ambiguity. The rotationally-resolved vibrational spectra were measured with an unapodized resolution of 0.00064 cm-1 using synchrotron-based Fourier transform infrared (FTIR) spectroscopy at the Canadian Light Source...

OBJECTIVES: Prussak's space (PS) is an intricate middle ear region which may play an essential role in the development of middle ear disease. The three-dimensional (3D) anatomy of the human PS and its drainage routes remain relatively unknown. Earlier studies have histologically analyzed PS, by micro-dissection and endoscopy. Here, we used synchrotron-radiation phase-contrast imaging (SR-PCI), 3D reconstructions, and modeling to study the framework of the human PS, including aeration pathways...

Adolescence is a time of increased risk for developing symptoms of anxiety and depression, especially for girls. The stress and social isolation experienced during confinement add new threats to already vulnerable adolescents' daily lives. This study is aimed at determining which sociodemographic characteristics (age, family composition, achievement), confinement habits (schedule, new hobby, sleep duration, cellphone and computer use, sports, schoolwork), and sources of support (parents and teachers) are associated with more or less internalized symptoms in Canadian adolescents...

BACKGROUND: When there is insufficient mother's milk for preterm infants, fortified human donor milk (DM) is the preferred supplement. Recently, there is growing interest in providing DM to term infants. Aside from vitamin D, mother's milk is a complete source of nutrition for term infants. It is unknown whether supplementation of micronutrients is required for term infants exclusively fed DM, particularly nutrients affected by heat processing, such as vitamin C. The objective of this study was to determine the total vitamin C content in DM and whether it would be adequate for an infant exclusively fed DM...

X-ray phase contrast imaging generates contrast from refraction of X-rays unlike absorption in conventional radiology. That enhances visualization of soft tissues, often at a reduced absorption radiation. Our goal is to develop a contrast agent for X-ray in-line phase contrast imaging based on ultrasound microbubbles (MBs), by assessing size, shell material, and concentration. We constructed MBs with two different shell materials: phospholipid and polyvinyl-alcohol (PVA). Polydisperse perfluorobutane-core lipid-MBs were size separated using centrifugation into five groups between 1 and 10 μm...

Synchrotron radiation-based infrared microspectroscopy (SR-IMS) is a non-destructive bioanalytical technique with a high signal to noise ratio and high ultra-spatial resolution (3-10µm). It is capable to explore the microstructures of plant tissues in a chemical sense and provide information on the composition, structure, and distribution of chemical compounds/ functional groups. The objective of this study was to illustrate how the SR-IMS can be used to image the internal microstructures of chickpea seed tissue on a cellular level...

Suicidality is an important contributor to disease burden worldwide. We examine the developmental and environmental correlates of reported suicidal ideation at age 15 and develop a new evolutionary model of suicidality based on life history trade-offs and hypothesized accompanying modulations of cognition. Data were derived from the National Longitudinal Survey of Children and Youth (Statistics Canada) which collected information on children's social, emotional, and behavioral development in eight cycles between 1994 and 2009...

PURPOSE: Sexual minority adults experience fivefold greater risk of suicide attempt, as compared with heterosexuals. Establishing age-specific epidemiological patterns of suicide is a prerequisite to planning interventions to redress the sexual orientation suicide inequity, and such patterns must be carefully interpreted in light of correlated period and cohort effects. We, therefore, combined US and Canadian data (1985-2017) from primary (two pooled multi-year national surveys, N = 15,477 and N = 126,463) and secondary (published, meta-analytic, N = 122,966) sources to separately estimate age, period, and cohort trends in self-reported suicide attempts among sexual minorities...

The Canadian Macromolecular Crystallography Facility (CMCF) consists of two beamlines dedicated to macromolecular crystallography: CMCF-ID and CMCF-BM. After the first experiments were conducted in 2006, the facility has seen a sharp increase in usage and has produced a significant amount of data for the Canadian crystallographic community. Upgrades aimed at increasing throughput and flux to support the next generation of more demanding experiments are currently under way or have recently been completed. At CMCF-BM, this includes an enhanced monochromator, automounter software upgrades and a much faster detector...

Core samples from petroleum wells are costly to obtain, hence drill cuttings are commonly used as an alternative source of rock measurements for reservoir, basin modelling, and sedimentology studies. However, serious issues such as contamination from drilling mud, geological representativeness, and physical alteration can cast uncertainty on the results of studies based on cuttings samples. This paper provides a unique comparative study of core and cuttings samples obtained from both vertical and horizontal sections of a petroleum well drilled in the Canadian Montney tight gas siltstone reservoir to investigate the suitability of cuttings for a wide range of geochemical and petrophysical analyses...

Xylem anomalies that are caused by unusual climate events have long been used to aid cross-dating in tree ring research. Here, we analyzed a range of xylem anomalies in a 39-year-old common garden experiment of white spruce ( Picea glauca [Moench] Voss) in central Alberta, Canada, designed to investigate local adaptation. We extracted wood cores from trees representing 24 provenances covering much of the species range across the Canadian boreal forest. Using a double stain and light microscopy analysis, four xylem anomalies and their causes could be distinguished: (1) frost rings indicate issues with synchronizing the onset of growth with the start of the growing season, and were prevalent in young trees; (2) light rings represent thin cell walls caused by an insufficient growing season length, most prevalent in southern sources; (3) blue rings were caused by a failure to complete lignification of new wood due to an early end of the growing season; and (4) double rings represent density fluctuations due to drier than normal summers...