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Search Publications by: Christopher Sims (Fed)

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Displaying 1 - 25 of 41

Rheology and Microstructural Behavior of Semidilute Suspensions of Semiflexible Rods across Five Decades of Shear Rate

February 18, 2025
Author(s)
Paul Salipante, Ryan Murphy, Steve Kuei, Jeffrey Fagan, Christopher Sims, Kathleen Weigandt, Steven Hudson
Rod-like particles are efficient rheology modifiers and are commonly found in a variety of biological and industrially relevant suspensions, from biofilaments to worm-like surfactant micelles. These suspensions display strong shear-thinning behavior, and

Interlaboratory Measurement of Adeno-Associated Virus: Comparative Quantification of Full and Empty Capsids

December 26, 2024
Author(s)
Sean Lehman, Wyatt N. Vreeland, Jerome Jacques, Sharee Adams-Hall, Shreya Ahuja, Adnan Arnaout, Hunter Balduf, Ivan Budyak, Thomas Cleveland, Dennis Delgado, James Deng, Brandon Doyle, David L. Duewer, Carsten Elger, Jeffrey Fagan, Tim Guo, Jorge Haller, Luisa Hilgenfeld, Van Hoang, Allison Huldin, Matthew Hyatt, Sambit Kar, Sandeep Kedia, Bashkim Kokona, Amy Liu, Li Ma, Diane McCarthy, He Meng, Easton Noble, Veronika Oettle, Andrew Pla, Thomas Powers, Dean Ripple, Herbert Runnels, Raphael Ruppert, Florian Semmelmann, Christopher Sims, Saurabh Singh, Ronald Toth, Austin Vogt, Sabine Wenzel, Neal Whitaker, Zhiwen Yang, Brandon Zhuang
Recombinant adeno-associated virus (AAV) is one of the main viral vector-based gene therapy platforms. AAV is a virus consisting of a ≈25 nm diameter capsid with a ≈4.7 kb cargo capacity. The safety and efficacy depend on the correct encapsidation of the

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