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Search Publications by: David A LaVan (Fed)

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Displaying 1 - 18 of 18

Polyethyleneimine/polyethylene glycol-conjugated gold nanoparticles as nanoscale positive/negative controls in nanotoxicology: Testing in frog embryo teratogenesis assay-Xenopus and mammalian tissue culture system

March 15, 2023
Vytas Reipa, Alessandro Tona, Feng Yi, Bryant C. Nelson, David A. LaVan, Vincent A. Hackley, Tae Joon Cho
Despite the great potential of using positively charged gold nanoparticles (AuNPs) in nanomedicine, no systematic studies have been reported on their synthesis optimization or colloidal stability under physiological conditions until a group at the National

Crystallize it before it diffuses: Thin -film growth of the phosphorus-rich semiconductor CuP2

July 13, 2022
Feng Yi, David A. LaVan, Andrea Crovetto, Danny Kojda, Karen Heinselman, Klaus Habicht, Thomas Unold, Andriy Zakutayev
Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid state chemistry literature. Yet, very little is known about the thin- film synthesizability and properties of even the simplest binary compounds

Growth and Decomposition of Pt Surface Oxides

June 28, 2022
Feng Yi, Shane Arlington, Justin Gorham, William Alexander Osborn, Slavomir Nemsak, Ethan Crumlin, David A. LaVan
The formation and thermal stability of Pt surface oxides on Pt thin film were studied in situ using ambient pressure x-ray photoelectron spectroscopy (AP-XPS). AP-XPS allows us to monitor the chemical states of both adsorbed reactants and underlying

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

September 16, 2021
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

Versatile fluidic cell for in-situ electrochemical measurements in SEM

July 24, 2016
Jeyavel Velmurugan, Ana Stevanovic, Feng Yi, David A. LaVan, Andrei Kolmakov
Electrochemical techniques such as like electrodeposition are crucially important for fabrication of nanostructured materials. The details of cluster nucleation and growth at early stages of electrodeposition are extremely important for morphology and

Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

August 18, 2014
Michael D. Grapes, Thomas LaGrange, Lawrence Henry Friedman, Bryan W. Reed, Geoffrey H. Campbell, Timothy P. Weihs, David A. LaVan
Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here we couple a nanocalorimeter with an extremely fast in situ microstructural characterization

Nanofiber Supported Phospholipid Bilayers

December 27, 2009
Feng Yi, Jian Xu, David A. LaVan
This work reports on the creation and characterization of nanofiber supported bilayers to mimic the hydrodynamic, chemical and mechanical environment provided by the actin network which supports natural lipid bilayers within a cell. Lipid bilayers were

Measurement of heat capacity and enthalpy of formation of Nickel Silicide using Nano-calorimetry

November 2, 2009
Ravi Kummamuru, Lito De La Rama, Liang Hu, Mark D. Vaudin, Mikhail Efremov, Martin L. Green, David A. LaVan, Leslie Allen
We present characterization of energetics of the reaction between nickel and silicon thin films using differential scanning nano-calorimetry (nano-DSC). For the first time, nano-DSC measurements up to 850 °C and of enthalpy of thin film reactions have been

Droplet Formation at Microfluidic T-junctions

December 31, 2008
David A. LaVan, Xiang Xu
Analysis of droplet formation in microfluidic systems is important to understand the operation of these devices, and to permit optimal design and process control. Droplet formation in microfluidic T-junction devices was studied using experimental and

Designing artificial cells to harness the biological ion gradient

November 23, 2008
Jian Xu, David A. LaVan
Cell membranes contain numerous natural nanoscale conductors, i.e. ion channels and ion pumps1-4, that work in concert to form transmembrane or transcellular ion gradients that can be triggered to release an action potential (AP)1, 5. Can artificial cells