92 results match your criteria: "Metrology Research Centre[Affiliation]"

An introduction to machine learning tools for the analysis of microplastics in complex matrices.

Environ Sci Process Impacts

November 2024

Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada.

As microplastic (MP) particles continue to spread globally, their pervasive presence is increasingly problematic. Analyzing MPs in matrices as varied as soil, river water, and biosolid fertilizers is critical, as these matrices directly impact the food sources of plants, animals, and humans. Current analytical methods for quantifying and identifying MPs are limited due to labor-intensive extraction processes and the time and effort required for counting and analysis.

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Cytotoxic Potencies of Zinc Oxide Nanoforms in A549 and J774 Cells.

Nanomaterials (Basel)

October 2024

Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 7K4, Canada.

Article Synopsis
  • Zinc oxide nanoparticles (ZnO NPs) are widely used in consumer products and medicine, raising health concerns due to potential human exposure and toxicity.
  • A study assessed various sized and coated ZnO NPs for cytotoxicity in human lung and mouse immune cells, showing that toxicity varied based on particle characteristics and cell types.
  • The research linked cytotoxic effects to cellular oxidative stress and protein signaling alterations, highlighting the need for more studies to further understand the toxicity mechanisms of different ZnO nanoforms for better health risk assessment.
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In most industrialized countries, power transformers built several decades ago are approaching the end of their operational lifespan. The ongoing energy transition, focused on developing 100% renewable energy sources and accelerating global transportation electrification, further exacerbates these assets. Combined with rising electricity demand, there is an increasing risk of critical transformers' degradation acceleration.

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Relating the ultrasonic and aerosol filtration properties of filters.

Sci Rep

July 2024

Department of Ultrasonic and Sensors Technologies, Physical and Information Technologies Institute (ITEFI), Spanish National Research Council, Serrano 144, 28006, Madrid, Spain.

Non-contact methods are useful to improve the quality control of particle filtration media. The purpose of this paper is to investigate the correlation between the filtration efficiency of a porous sheet and its ultrasonic properties obtained using a non-contact technique. An air-coupled ultrasonic technique is used to obtain rapid measurements without affecting the integrity of the material.

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A tomographic spatial-unfolding method for Compton gamma imaging measurements.

J Environ Radioact

September 2024

Canadian Hazards Information Service, Natural Resources Canada, Ottawa, Ontario, Canada.

An advanced spatial-unfolding technique capable of reconstructing the activity distribution within an exclusion zone from Compton gamma imager measurements taken outside of it is introduced. Although the method is generally applicable to extended sources, we demonstrate it here on a calibrated Cs-137 point source through Monte Carlo simulation studies as well as with measurements made using a Silicon Compton Telescope for Safety and Security (SCoTSS) gamma imager. For synthetic data the method accurately reconstructs the total activity contained within the mapped zone of interest, even when the size of the basis elements used to reconstruct the activity distribution is larger than the source itself.

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AAPM WGTG51 Report 385: Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy electron beams.

Med Phys

September 2024

Département de radio-oncologie, CIUSSS de l'Est-de-l'Île-de-Montréal - Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada.

An Addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water is presented for electron beams with energies between 4 MeV and 22 MeV ( ). This updated formalism allows simplified calibration procedures, including the use of calibrated cylindrical ionization chambers in all electron beams without the use of a gradient correction. New data are provided for electron beams based on Monte Carlo simulations.

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Toward an international standardisation roadmap for nanomedicine.

Drug Deliv Transl Res

September 2024

Laboratoire National de métrologie et d'Essais (LNE), ZA Trappes-Elancourt, 29 Rue Roger Hennequin, 78190, Trappes, France.

The French National Metrology Institute (LNE) initiated a series of events to identify priorities for test methods and their harmonisation that directly address regulatory needs in Nanomedicine. One of these workshops entitled "The International Standardisation Roadmap for Nanomedicine" held in October 2023 (Paris, France) brought together key experts in the characterisation of nanomedicines and medical products containing nanomaterials, including the Joint Research Centre of the European Commission, SINTEF Industry and the metrology institutes of France, the UK, the USA and Canada, two flagship initiatives of the European Commission (PHOENIX and SAFE-n-MEDTECH Open Innovation Test Beds), representatives of a working party on mRNA vaccines at the European Directorate for the Quality of Medicines (EDQM) and members of international standardisation and pre-normative organisations (including CEN, ISO, ASTM, VAMAS). Two take-home message came out from the discussion.

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Background: The newly available ZAP-X stereotactic radiosurgical system is designed for the treatment of intracranial lesions, with several unique features that include a self-shielding, gyroscopic gantry, wheel collimation, non-orthogonal kV imaging, short source-axis distance, and low-energy megavoltage beam. Systematic characterization of its radiation as well as other properties is imperative to ensure its safe and effective clinical application.

Purpose: To accurately determine the radiation output of the ZAP-X with a special focus on the smaller diameter cones and an aim to provide useful recommendations on quantification of small field dosimetry.

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Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract with a complex and multifactorial etiology, making it challenging to treat. While recent advances in immunomodulatory biologics, such as antitumor necrosis factor-α (TNF-α) antibodies, have shown moderate success, systemic administration of antibody therapeutics may lead to several adverse effects, including the risk of autoimmune disorders due to systemic cytokine depletion. Transient RNA interference using exogenous short interfering RNA (siRNA) to regulate target gene expression at the transcript level offers an alternative to systemic immunomodulation.

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Microplastic particles in arable soil are expected to impact the environment and potentially human health. The application of municipal biosolids (MBs) to agricultural land presents a further dilemma in that biosolids act as a fertilizer for crop growth, and a disposal pathway for wastewater treatment plants. They are also a direct path for emerging contaminants, such as microplastics to enter the terrestrial environment.

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Harnessing graphene oxide nanocarriers for siRNA delivery in a 3D spheroid model of lung cancer.

Biomater Sci

September 2023

Metrology Research Centre, National Research Council of Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.

Gene therapy has been recently proposed as an effective strategy for cancer treatment. A significant body of literature proved the effectiveness of nanocarriers to deliver therapeutic agents to 2D tumour models, which are simple but not always representative of the reality. In this study, we analyze the efficiency of 3D spheroids combined with a minimally modified graphene oxide (GO)-based nanocarrier for siRNA delivery as a new system for cell transfection.

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Selenized yeast is commonly used as a highly bioavailable source of selenium in dietary supplements and feed additives and is used in research settings in various disciplines due to the large number of selenium-containing metabolites formed during growth. With the selenomethionine being the major form of selenium present in selenized yeasts, its accurate quantitation is essential, however, values are frequently underestimated due to the costly and time-consuming hydrolysis-based sample preparation required to release the selenoamino acid from proteins for analysis. The National Research Council Canada has developed an 82-Se-enriched selenized yeast Certified Reference Material, SEEY-1 (DOI: 10.

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Background: Electron synchrotrons produce x-ray beams with dose rates orders of magnitude greater than conventional x-ray tubes and with beam sizes on the order of a few millimeters. These characteristics put severe challenges on current dosimeters to accurately realize absorbed dose or air kerma.

Purpose: This work seeks to investigate the suitability of a novel aluminum-based calorimeter to determine absorbed dose to water with an uncertainty significantly smaller than currently possible with conventional detectors.

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Localized surface plasmon resonance biosensor chip surface modification and signal amplifications toward rapid and sensitive detection of COVID-19 infections.

Biosens Bioelectron

September 2023

Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, K1N 6N5, Canada. Electronic address:

We developed a multi-pronged approach to enhance the detection sensitivity of localized surface plasmon resonance (LSPR) sensor chips to detect SARS-CoV-2. To this end, poly(amidoamine) dendrimers were immobilized onto the surface of LSPR sensor chips to serve as templates to further conjugate aptamers specific for SARS-CoV-2. The immobilized dendrimers were shown to reduce surface nonspecific adsorptions and increase capturing ligand density on the sensor chips, thereby improving detection sensitivity.

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Article Synopsis
  • - The study investigates magic-size clusters (MSCs) of colloidal II-VI metal chalcogenides, specifically looking at how some MSCs are optically inactive, while others are active with distinct photoluminescence (PL) signals.
  • - Researchers found that the PL-inactive CdS MSC-322 can transform into PL-active MSC-328 and MSC-373 when acetic acid is present, demonstrating varying optical absorption characteristics.
  • - The transformation of these clusters involves complex chemical processes, where precursor compounds evolve through monomer substitution and addition, highlighting the role of sulfur and cadmium in determining the optical properties of the MSCs.
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The field of isomerization reactions for colloidal semiconductor magic-size clusters (MSCs) remains largely unexplored. Here, we show that MSCs isomerize via two fundamental pathways that are regulated by the acidity and amount of an incoming ligand, with CdTeSe as the model system. When MSC-399 isomerizes to MSC-422 at room temperature, the peak red-shift from 399 to 422 nm is continuous (pathway 1) and/or stepwise (pathway 2) as monitored in situ and in real time by optical absorption spectroscopy.

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Thickness measurements of graphene oxide flakes using atomic force microscopy: results of an international interlaboratory comparison.

Nanotechnology

March 2023

Technology Innovation Center of Graphene Metrology and Standardization for State Market Regulation, National Institute of Metrology (NIM), Beijing, 100029, People's Republic of China.

Flake thickness is one of the defining properties of graphene-related 2D materials (GR2Ms), and therefore requires reliable, accurate, and reproducible measurements with well-understood uncertainties. This is needed regardless of the production method or manufacturer because it is important for all GR2M products to be globally comparable. An international interlaboratory comparison on thickness measurements of graphene oxide flakes using atomic force microscopy has been completed in technical working area 41 of versailles project on advanced materials and standards.

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Under healthy conditions, pro- and anti-phagocytic signals are balanced. Cluster of Differentiation 47 (CD47) is believed to act as an anti-phagocytic marker that is highly expressed on multiple types of human cancer cells including acute myeloid leukemia (AML) and lung and liver carcinomas, allowing them to escape phagocytosis by macrophages. Downregulating CD47 on cancer cells discloses calreticulin (CRT) to macrophages and recovers their phagocytic activity.

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. While the accuracy of dose calculations in water with Acuros XB is well established, experimental validation of dose in bone is limited. Acuros XB reports both dose-to-medium and dose-to-water, and these values differ in bone, but there are no reports of measurements of validation in bone.

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Standards governing face masks differ in the test methods used to determine sub-micron particle filtration efficiency (PFE), such that the meaning of PFE is not universal. Unifying the meaning of PFE requires data using these different test methods to drive improvements in standards. This simple data set provides the equivalence between two major test methods used to assess PFE: (1) a test method using a neutralized, polydisperse sodium chloride (NaCl) and (2) a test method using an unneutralized, "monodisperse" polystyrene latex sphere (PSL) aerosols.

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Cannabis vaping involves the vaporization of a cannabis vaping liquid or solid via a vaping accessory such as a vape pen constructed of various metals or other parts. An increasing number of reports advocate for expansion of the testing and regulation of metal contaminants in cannabis vape liquids beyond the metals typically tested such as arsenic, cadmium, mercury, and lead to reflect the possibility of consumers' exposure to other metal contaminants. Metal contaminants may originate not only from the cannabis itself but also from the vape devices in which the cannabis vape liquid is packaged.

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Surface modification of poly(styrene) 96-well plates using aptamers via a dendrimer-templated strategy to enhance ELISA performances.

Colloids Surf B Biointerfaces

January 2023

Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa ON K1N 6N5, Canada. Electronic address:

Poly(styrene) (PS) 96-well plates were surface modified to improve the detection performances of an otherwise traditional enzyme-linked immunosorbent assay (ELISA). Poly(amidoamine) generation 7 (G7) dendrimers were covalently immobilized on the surface of PS plates and subsequently conjugated with aptamers specific for a model analyte, i.e.

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Evaluation of Adjuvant Activity and Bio-Distribution of Archaeosomes Prepared Using Microfluidic Technology.

Pharmaceutics

October 2022

Human Health Therapeutics, National Research Council Canada, Ottawa, ON K1A0R6, Canada.

Archaeosomes, composed of sulfated lactosyl archaeol (SLA) glycolipids, have been proven to be an effective vaccine adjuvant in multiple preclinical models of infectious disease or cancer. They have classically been prepared using a thin-film hydration method with an average particle size of 100-200 nm. In this study, we developed methods to generate SLA archaeosomes at different sizes, i.

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Lipid based nanocarriers are one of the most effective drug delivery systems that is evident from the recent COVID-19 mRNA vaccines. The main objective of this study was to evaluate toxicity of six lipid based formulations with three surface charges-anionic, neutral or cationic, to establish certified reference materials (CRMs) for liposomes and siRNA loaded lipid nanoparticles (LNP-siRNA). Cytotoxicity was assessed by a proliferation assay in adherent and non-adherent cell lines.

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Transformations of Magic-Size Clusters via Precursor Compound Cation Exchange at Room Temperature.

J Am Chem Soc

October 2022

Engineering Research Center in Biomaterials, Sichuan University, Chengdu, Sichuan 610065, P. R. China.

The transformation of colloidal semiconductor magic-size clusters (MSCs) from zinc to cadmium chalcogenide (ZnE to CdE) at low temperatures has received scant attention. Here, we report the first room-temperature evolution of CdE MSCs from ZnE samples and our interpretation of the transformation pathway. We show that when prenucleation stage samples of ZnE are mixed with cadmium oleate (Cd(OA)), CdE MSCs evolve; without this mixing, ZnE MSCs develop.

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