A new secondary isotopic reference material has been prepared from Puerto Rico precipitation, which was filtered, homogenised, loaded into glass ampoules, sealed with a torch, autoclaved to eliminate biological activity, and calibrated by dual-inlet isotope-ratio mass spectrometry. This isotopic reference material, designated as USGS48, is intended to be one of two isotopic reference waters for daily normalisation of stable hydrogen (δ(2)H) and stable oxygen (δ(18)O) isotopic analysis of water with a mass spectrometer or a laser absorption spectrometer. The δ(2)H and δ(18)O values of this reference water are-2.0±0.4 and-2.224±0.012 ‰, respectively, relative to Vienna Standard Mean Ocean Water on scales normalised such that the δ(2)H and δ(18)O values of Standard Light Antarctic Precipitation reference water are-428 and-55.5 ‰, respectively. Each uncertainty is an estimated expanded uncertainty (U=2u(c)) about the reference value that provides an interval that has about a 95 % probability of encompassing the true value. This isotopic reference water is available by the case of 144 glass ampoules containing 5 mL of water in each ampoule.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1080/10256016.2014.905555 | DOI Listing |
Open Heart
January 2025
Department of Cardiology, University Hospital Basel, Basel, Switzerland.
Background: The majority of functional ischemia tests in patients with suspected chronic coronary syndromes (CCS) yield normal results. Implementing gatekeepers for patient preselection, such as pretest probability (PTP) and/or coronary artery calcium score (CACS), could reduce the number of normal scan results, radiation exposure and costs. However, the efficacy and safety of these approaches remain unclear.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Neuroscience Research Institute, Gachon University, Incheon 21565, Republic of Korea.
To elucidate the potential roles of presynaptic and postsynaptic serotonergic activity in impulsivity traits, we investigated the relationship between self-reported impulsiveness and serotonin transporter (5-HTT) and 5-HT2A receptors in healthy individuals. In this study, 26 participants completed 3-Tesla magnetic resonance imaging and positron emission tomography with [C]DASB and [C]MDL100907. To quantify 5-HTT and 5-HT2A receptor availability, the binding potential (BP) of [C]DASB and [C]MDL100907 was derived using the simplified reference tissue model with cerebellar gray matter as the reference region.
View Article and Find Full Text PDFPol J Radiol
November 2024
Radiology Department, Mansoura University, Mansoura, Egypt.
Purpose: Diagnosis of perianal fistula represents a challenge for surgeons. It is well known that magnetic resonance imaging (MRI) plays an important role in that. The new 3D MRI sequence VISTA (Volume ISotopic Turbo spin echo Acquisition) can improve detection and characterization of perianal fistula compared with two-dimensional (2D) sequences.
View Article and Find Full Text PDFBraz Oral Res
January 2025
Universidade Federal do Ceará - UFC, School of Pharmacy, Dentistry and Nursing, Post-graduate Program in Dentistry, Fortaleza, CE, Brazil.
This study evaluated some physicochemical properties of an experimental tricalcium silicate-based cement (ETSC) indicated for use as pulp capping or endodontic repair material; Biodentine (BD) and White MTA-Angelus (MTA) cements served as comparators. Setting time, radiopacity, sorption, and solubility were determined according to ISO 6876/2012 and compressive strength according to ISO 9917-1/2019. pH and calcium ion release capacity were also assessed.
View Article and Find Full Text PDFProc Biol Sci
January 2025
Institute for Geosciences, Johannes Gutenberg University, Mainz, Germany.
Dietary preferences of extant reptiles can be directly observed, whereas diet reconstruction of extinct species typically relies on morphological or dental features. More specific information about the ingested diet is contained in the chemistry of hard tissues. Stable isotopes of calcium and strontium show systematic fractionations between diet and skeletal bioapatite, which is applied for diet and trophic-level reconstructions of extant and extinct vertebrate species.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!