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Chemistry

Analytical chemistry

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Displaying 226 - 250 of 2094

Creation and Release of an Updated NIST DART-MS Forensics Database

June 17, 2021
Author(s)
Edward Sisco, Arun Moorthy, Laura M. Watt
Facing increasing caseloads and an everchanging drug landscape, forensic laboratories have been implementing new analytical tools. Direct analysis in real time mass spectrometry (DART-MS) is often one of these tools because it provides a wealth of

Copper-binding anticancer peptides from the piscidin family: an expanded mechanism that encompasses physical and chemical bilayer disruption

June 16, 2021
Author(s)
Fatih Comert, Frank N. Heinrich, Ananda Chowdhury, Mason Schoeneck, Caitlin Darling, Kyle Anderson, M. Daben J. Libardo, Alfredo Angeles-Boza, Vitalii I. Silin, Myriam Cotten, Mihaela Mihailescu
In the search for novel broad‑spectrum therapeutics to fight chronic infections, inflammation, and cancer, host defense peptides (HDPs) have garnered increasing interest. Characterizing their biologically‑active conformations and minimum motifs for

Trace element proxies and stable isotopes used to identify water quality threats to elkhorn coral (Acropora palmata) at two national parks in St. Croix, USVI

June 11, 2021
Author(s)
Amanda Bayless, Steven Christopher, Jennifer Ness, Charles Barber, Russell D. Day, Cheryl M. Woodley, C. Anna Toline
Chronic biological impairments of reef organisms have been documented at two national parks in St. Croix, USVI. Although several water quality parameters have been out of compliance with USVI water quality criteria, whether these parameters or other

Witnessing the survival of time-energy entanglement through biological tissue and media

June 9, 2021
Author(s)
Daniel J. Lum, Michael Mazurek, Alexander Mikhaylov, Kristen M. Parzuchowski, Ryan M. Wilson, Marcus Cicerone, Ralph Jimenez, Thomas Gerrits, Martin Stevens, Charles Camp
In this work, we demonstrate the preservation of time-energy entanglement of near-IR photons through thick biological media ( 1.55 mm) and tissue ( 235 um) at room temperature. Using a Franson-type interferometer, we demonstrate interferometric contrast of

A new measurement of the 122Sb half-life

June 5, 2021
Author(s)
Giancarlo D'Agostino, Marco Di Luzio, Nicholas Sharp, Massimo Oddone
Following significant discrepancies observed in rescaling collected 122Sb -peak count rates to a reference time by decay corrections, we looked at the literature supporting the presently recommended 2.7238(2) d 122Sb half-life value. The reading

Combining secondary ion mass spectrometry image depth profiling and single particle inductively coupled plasma mass spectrometry to investigate the uptake and biodistribution of gold nanoparticles in Caenorhabditis elegans

May 20, 2021
Author(s)
Monique Johnson, Joe Bennett, Antonio Montoro Bustos, Shannon Hanna, Andrei Kolmakov, Nicholas Sharp, Elijah Petersen, Christopher Sims, Bryant Nelson, Patricia Lapasset
Analytical techniques capable of determining the spatial distribution and quantity (mass and/or particle number) of engineered nanomaterials in organisms are essential for characterizing nano-bio interactions and for nanomaterial risk assessments. Here, we

Environmental Protection Agency Blind Audit 2018

May 17, 2021
Author(s)
Christina Cecelski, Cassie Goodman, Jennifer Carney
The U.S. Environmental Protection Agency (EPA) conducted a blind audit of EPA protocol calibration gas mixtures produced by specialty gas manufactures. The objective was to determine the amount-of-substance fraction (concentration) of the analytes in the

Vitamin D Standardization Program (VDSP) intralaboratory study for the assessment of 25-hydroxyvitamin D assay variability and bias

May 17, 2021
Author(s)
Johanna Camara, Stephen Wise, Christopher T. Sempos, Pierre Lukas, Caroline LeGoff, Stephanie Peeters, Carolyn Burdette, Federica Nalin, Grace Hahm, Ramon Durazo-Arvizu, Adam J. Kuszak, Joyce M. Merkel, E. Cavalier
An intralaborabory comparison study to assess the performance of assays for the determination of serum total 25-hydroxyvitamin D [25(OH)D] was conducted in 2017 as part of the Vitamin D Standardization Program (VDSP). The intralaboratory study consisted of

Decision Tree for Key Comparisons

April 27, 2021
Author(s)
Antonio Possolo, Amanda Koepke, David Newton, Michael R. Winchester
This contribution describes a Decision Tree intended to guide the selection of statistical models and data reduction procedures in key comparisons (KCs). The Decision Tree addresses a specific need of the Inorganic Analysis Working Group (IAWG) of the

Development of an LC-MS/MS Reference Method for the Standardization of Analytical Methods to Measure Lipoprotein(a) in Plasma

April 1, 2021
Author(s)
Santica Marcovina, Noemie Clouet-Foraison, Marlys Koschinsky, Mark Lowenthal, Michael Boffa, Andrew Hoofnagle, Tomas Vaisar
Background: Use of Lipoprotein(a) levels for identification of individuals at high risk for cardiovascular disease is hampered by the high size polymorphism of apolipoprotein(a) which strongly impacts immunochemical methods resulting in discordant values

Determination of Total Arsenic and Hydrophilic Arsenic species in Seafood

March 1, 2021
Author(s)
Caleb Luvonga, Catherine A. Rimmer, Lee L. Yu, Sang Bok Lee
Marine organisms are vital sources of staple and functional food but are also the major dietary route of human exposure to total arsenic. We report the total arsenic content and the mass fractions of hydrophilic arsenic species from five different marine

A Comparison of Measurement Methods for Alcohol-Based Hand Sanitizers

February 26, 2021
Author(s)
Mary Bedner, Jacolin Murray, Aaron A. Urbas, William A. MacCrehan, Walter Brent Wilson
The production and demand for hand sanitizers have increased dramatically during the coronavirus disease 2019 (COVID-19) health emergency. To be deemed effective and safe, hand sanitizers should contain at least 60 % alcohol (typically ethanol) as well as

A new highly enriched 233U reference material for improved simultaneous determination of uranium amount and isotope amount ratios in trace level samples

January 26, 2021
Author(s)
Richard Essex, Ross W. Williams, Kayron T. Rogers, Cole R. Hexel, Tashi Parsons-Davis, Kerri C. Treinen
A highly-enriched 233U reference material (>0.99987 n(233U)/n(U)) has been prepared and characterized for use as an isotope dilution mass spectrometry spike. An ion exchange separation was performed on 1 gram of high purity 233U to further reduce trace
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