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Search Publications by: Christopher Sims (Fed)

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Displaying 1 - 21 of 21

Orthogonal Determination of Competing Surfactant Adsorption onto Single-Wall Carbon Nanotubes During Aqueous Two-Polymer Phase Extraction via Fluorescence Spectroscopy and Analytical Ultracentrifugation

July 31, 2024
Author(s)
Christopher Sims, Jeffrey Fagan
A combination of analytical ultracentrifugation (AUC) and fluorescence spectroscopy are utilized to orthogonally probe compositions of adsorbed surfactant layers on the surface of (7,5) species single-wall carbon nanotubes (SWCNTs) under conditions known

Introduction of nanoscale positive controls for nanotoxicology: A new aspect of utilization of stability-enhanced Gold-Polyethyleneimine conjugates (Au-PEIs)

November 8, 2022
Author(s)
Tae Joon Cho, Vincent A. Hackley, Vytas Reipa, Alessandro Tona, Christopher Sims, Natalia Farkas
Polyethyleneimine (PEI) conjugated gold nanoparticles (Au-PEIs) have potential use as positively charged gold nanoparticles (AuNPs) for nanomedical applications, due to their cationic surface that promotes cellular uptake and gene transfection. We report

Preparation, Characterization, and Biological Activity of Stability-Enhanced Polyethyleneimine-Conjugated Gold Nanoparticles (Au-PEI@NIST) for Biological Application

September 16, 2021
Author(s)
Tae Joon Cho, Vincent A. Hackley, Feng Yi, David A. LaVan, Vytas Reipa, Alessandro Tona, Bryant C. Nelson, Christopher Sims, Natalia Farkas
In this special publication, we report on a modified synthetic process that results in a stable suspension of Au-PEI nanoparticles, Au-PEI@NIST. Synthesized materials were characterized using an orthogonal approach that included dynamic light scattering

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 C. 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

A Reference High-Pressure CH4 Adsorption Isotherm for Zeolite Y: Results of an Interlaboratory Study

September 11, 2020
Author(s)
Huong Giang T. Nguyen, Christopher M. Sims, Blaza Toman, Jarod C. Horn, Roger D. van Zee, Mathias Thommes, Riaz Ahmad, Joeri F. Denayer, Gino V. Baron, Emilio Napolitano, Marek Bielewski, Enzo Mangano, Stefano Brandani, Broom Darren, M.J. Benham, Anne Dailly, Frieder Dreisbach, Satyannarayana Edubilli, Sasidhar Gumma, Jens Mollmer, Marcus Lange, Mi Tian, Tim Mays, T. Shigeoka, S. Yamakita, M. Hakuman, Y. Nakada, K. Nakai, Junyoung Hwang, Ronny Pini, Huan Jiang, Armin Ebner, Marjorie Nicholson, James Ritter, Judit Farrando Perez, Carlos Cuadrado, Joaquin Silvestre Albero, Christos Tampaxis, Theodore Steriotis, Daniela Rimnacova, Martina Svabova, Maryna Vorokhta, Hai Wang, Eric Bovens, Nicolas Heymans, Guy de Weireld
This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess methane adsorption isotherms on NIST Reference Material RM 8850

Measurement of Oxidatively Induced DNA Damage in Caenorhabditis elegans with High-Salt DNA Extraction and Isotope-Dilution Mass Spectrometry

August 27, 2019
Author(s)
Leona D. Scanlan, Pawel Jaruga, Sanem Hosbas Coskun, Christopher Sims, Shannon Hanna, Jamie L. Almeida, David N. Catoe, Bryant C. Nelson, Miral M. Dizdar, Erdem Coskun
Caenorhabditis elegans (C. elegans) is used as a medical and systems toxicity model organism for environmental and developmental assays that include high-throughput methods and genetic studies. However, little is known about background levels of

Approaches for the Quantitative Analysis of Oxidation State in Cerium Oxide Nanomaterials

September 21, 2018
Author(s)
Christopher M. Sims, Russell A. Maier, Aaron C. Johnston-Peck, Justin M. Gorham, Vincent A. Hackley, Bryant C. Nelson
Cerium oxide nanomaterials (nanoceria, CNMs) are receiving increased attention from the research community due to their unique chemical properties, most prominent of which is their ability to alternate between the Ce3+ and Ce4+ oxidation states. While many

Counting Caenorhabditis elegans: Protocol Optimization and Applications for Population Growth and Toxicity Studies in Liquid Medium

January 17, 2018
Author(s)
Steven Lund, Sanem Hosbas Coskun, Monique Johnson, Christopher Sims, Elijah Petersen, John T. Elliott, Bryant C. Nelson, Leona D. Scanlan, Shannon K. Hanna, Karina Brignoni, Patricia Lapasett
The nematode Caenorhabditis elegans is used extensively in molecular, toxicological and genetics research. However, standardized methods for counting nematodes in liquid culture do not exist despite the wide use of nematodes and need for accurate

Controlled Potential Electrooxidation of Genomic DNA

January 11, 2018
Author(s)
Vytautas Reipa, Donald H. Atha, Sanem Hosbas Coskun, Christopher M. Sims, Bryant C. Nelson
Exposure of mammalian cells to oxidative stress can result in DNA damage that adversely affects many cell processes. We used bulk electrolysis in an electrochemical system and gas chromatographic mass spectrometric analysis (GC/MS/MS) to control and

Redox-active Nanomaterials for Nanomedicine Applications

October 6, 2017
Author(s)
Christopher Sims, Shannon Hanna, Daniel A. Heller, Christopher Horoszko, Monique Johnson, Antonio Montoro Bustos, Vytas Reipa, Kathryn Riley, Bryant C. Nelson
Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of

Quantitative Analysis of Oxidation State in Cerium Oxide Nanomaterials

May 14, 2017
Author(s)
Christopher Sims, Russell Maier, Aaron Johnston-Peck, Justin Gorham, Vincent A. Hackley, Bryant C. Nelson
Cerium oxide nanoparticles (nanoceria) are receiving increased attention from the research community due to the large number and wide range of their current and potential applications. The attractiveness of nanoceria for these various applications is

Biophysical Characterization of Functionalized Titania Nanoparticles and Their Application in Dental Adhesives

February 2, 2017
Author(s)
Jirun Sun, Elijah Petersen, Stephanie S. Watson, Christopher Sims, Alexander Kassman, Stanislav Frukhtbeyn, Drago Skrtic, Meryem T. Ok, Deborah Jacobs, Qiang Ye, Bryant C. Nelson
It is demonstrated that carboxylic acid-functionalized titanium dioxide (TiO2) NPs produce significantly higher levels of reactive oxygen species (ROS) after visible light irradiation (400-800 nm, 1600 mW/cm2) in comparison to nonfunctionalized TiO2 NPs

Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis

December 16, 2016
Author(s)
Monique E. Johnson, Shannon Hanna, Antonio R. Montoro Bustos, Christopher M. Sims, Lindsay C. Elliott, Babak Nikoobakht, John T. Elliott, Richard D. Holbrook, Keana C. Scott, Karen E. Murphy, Elijah J. Petersen, Lee L. Yu, Bryant C. Nelson, Akshay Lingayat, Adrian C. Johnston
For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the

Emerging Metrology for High Throughput Nanomaterial Genotoxicology

August 26, 2016
Author(s)
Bryant C. Nelson, Christa W. Wright, Yuko Ibuki, Maria Moreno-Villanueva, Hanna L. Karlsson, Giel Hendriks, Christopher M. Sims, Neenu Singh, Shareen H. Doak
The rapid development of the engineered nanomaterial (ENM) manufacturing industry has accelerated the incorporation of ENMs into a wide variety of consumer products across the globe. Unintentionally or not, some of these ENMs may be introduced into the

Antioxidant Cerium Oxide Nanoparticles in Biology and Medicine

May 17, 2016
Author(s)
Bryant C. Nelson, Monique E. Johnson, Marlon L. Walker, Kathryn R. Riley, Christopher M. Sims
Previously, catalytic cerium oxide nanoparticles (CNPs, nanoceria, CeO2-x NPs) have been widely utilized for chemical mechanical planarization in the semiconductor industry and for reducing harmful emissions and improving fuel combustion efficiency in the