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Search Publications by: Kristen L Steffens (Fed)

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Displaying 1 - 25 of 31

Deep Learning Image Analysis of Nanoplasmonic Sensors: Toward Medical Breath Monitoring

November 23, 2022
Author(s)
Yangyang Zhao, Boqun Dong, Kurt D. Benkstein, Lei Chen, Kristen L. Steffens, Stephen Semancik
Sensing biomarkers in exhaled breath offers a potentially portable, cost-effective, and noninvasive strategy for disease diagnosis screening and monitoring, while high sensitivity, wide sensing range, and target specificity are critical challenges. We

Conformational Changes of Immobilized Polythymine due to External Stressors Studied with Temperature-Controlled Electrochemical Microdevices

February 17, 2021
Author(s)
Ramya Vishnubhotla, Sarah Robinson, Jon R. Askim, Christopher B. Montgomery, Kristen L. Steffens, Herman O. Sintim, Stephen Semancik
Conformational changes of single-stranded DNA (ssDNA) play an important role in a DNA strand's ability to bind to target ligands. A variety of factors can influence conformation, including temperature, ionic strength, pH, buffer cation valency, strand

Establishing Standards and Methods for Qualification and Validation of New Particle Measurement Technologies

November 12, 2019
Author(s)
Srivalli Telikepalli, Dean C. Ripple, Kurt D. Benkstein, Kristen L. Steffens, Michael J. Carrier, Christopher B. Montgomery
Numerous particle sizing and counting methods exist for measuring particles in the submicrometer, subvisible, and visible size range. This article will briefly describe some key aspects that need to be considered for the most commonly used methods in order

Miniaturized Nanohole Array Based Plasmonic Sensor for the Detection of Acetone and Ethanol with Insights into the Kinetics of Adsorptive Plasmonic Sensing

June 6, 2019
Author(s)
Yangyang Zhao, Kalisadhan Mukherjee, Kurt D. Benkstein, Libin Sun, Kristen L. Steffens, Christopher B. Montgomery, Stephen Semancik, Mona Zaghloul
The present work demonstrates development of a miniaturized plasmonic platform comprised of a Au nanohole array (NHA) on a Si/Si3N4 substrate. Plasmonic responses of the NHA platform, which is coated with Cu-benzenetricarboxylate metal organic framework

Reference Material 8634: Ethylene Tetrafluoroethylene for Particle Size Distribution and Morphology

May 1, 2019
Author(s)
Dean C. Ripple, Srivalli Telikepalli, Kristen L. Steffens, Michael J. Carrier, Christopher B. Montgomery, Nicholas W. Ritchie, John Lu
Reference Material (RM) 8634 is a NIST particle standard produced from abraded ethylene tetrafluoroethylene (ETFE), a chemically inert polymer, that will help standardize and allow more accurate monitoring of subvisible proteinaceous particles in

UV-assisted room-temperature chemiresistive NO2 sensor based on TiO2 thin film

December 24, 2015
Author(s)
Ting Xie, Nichole Sullivan, Kristen L. Steffens, Baomei Wen, Guannan Liu, Ratan K. Debnath, Albert Davydov, Romel D. Gomez, Abhishek Motayed
TiO2 thin film based, chemiresistive sensors for NO2 gas which operate at room temperature under ultraviolet (UV) illumination have been demonstrated in this work. The rf-sputter deposited and post-annealed TiO2 thin films have been characterized by atomic

MECHANISMS OF CRITICALITY IN ENVIRONMENTAL ADHESION LOSS

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Kristen L. Steffens, Deborah S. Jacobs, Bulent Akgun, Vogt D. Bryan
Moisture attack on adhesive joints is a long-standing scientific and engineering problem. A particularly interesting observation is that when the moisture level in certain systems exceeds a critical concentration, the bonded joint shows a dramatic loss of

Enriching 28Si beyond 99.9998 % for semiconductor quantum computing

August 5, 2014
Author(s)
Kevin J. Dwyer, Joshua M. Pomeroy, David S. Simons, June W. Lau, Kristen L. Steffens
Using a laboratory-scale apparatus, we enrich 28Si and produce material with 40 times less residual 29Si than previously reported. Starting from natural abundance silane gas, we offer an alternative to industrial gas centrifuges for providing materials

Time-resolved surface infrared spectroscopy during atomic layer deposition of TiO2 using tetrakis(dimethylamido)titanium and water

April 23, 2014
Author(s)
Brent A. Sperling, John Hoang, William A. Kimes, James E. Maslar, Kristen L. Steffens, Nhan V. Nguyen
Atomic layer deposition of titanium dioxide using tetrakis(dimethylamido)titanium (TDMAT) and water vapor is studied by reflection-absorption infrared spectroscopy (RAIRS) with a time resolution of 120 ms. Decomposition of the adsorbed TDMAT is observed

Solution-based functionalization of gallium nitride nanowires for protein sensor development

April 17, 2014
Author(s)
Albert Davydov, Elissa H. Williams, Vladimir P. Oleshko, Kristen L. Steffens, Igor Levin, Nancy J. Lin, Kristine A. Bertness, Amy Manocchi, M V. Rao, John A. Schreifels
A solution-based functionalization method for the specific and selective attachment of the streptavidin (SA) protein to gallium nitride (GaN) nanowires (NWs) is presented. By exploiting streptavidin's strong affinity for its ligand biotin, SA

A Generalized Strategy for Immobilizing Uniformly Oriented Membrane Proteins at Solid Interfaces

February 13, 2013
Author(s)
Amit NMN Vaish, Vitalii I. Silin, Marlon L. Walker, Kristen L. Steffens, Susan Krueger, Alexei A. Yeliseev, Klaus Gawrisch, David J. Vanderah
We present here a generalized strategy for immobilizing uniformly oriented membrane proteins onto a functionalized surface. Using water soluble nitrilotriacetic acid (NTA)-terminated oligo(ethylene glycol) thiols, a histidine-tagged G protein-coupled

Selective Streptavidin Bioconjugation on Si and SiC nanowires for Biosensor Applications.

January 14, 2013
Author(s)
Elissa H. Williams, John A. Schreifels, Mulpuri V. Rao, Albert Davydov, Vladimir P. Oleshko, Nancy J. Lin, Kristen L. Steffens, Sergiy Krylyuk, Kristine A. Bertness, Amy Manocchi, Yaroslav Koshka
A functionalization method for the specific and selective immobilization of the streptavidin (SA) protein on semiconductor nanowires (NWs) was developed. Silicon (Si) and silicon carbide (SiC) NWs were functionalized with 3-aminopropyltriethoxysilane

Selective Streptavidin Bioconjugation on Si, SiC, and GaN Nanowires for Biosensor Applications.

October 19, 2012
Author(s)
Elissa H. Williams, John A. Schreifels, Mulpuri V. Rao, Albert Davydov, Vladimir Oleshko, Nancy Lin, Kristen L. Steffens, Sergiy Krylyuk, Kristine A. Bertness, Amy Manocchi, Yaroslav Koshka
A functionalization method for the specific and selective immobilization of the streptavidin (SA) protein on semiconductor nanowires (NWs) was developed. Silicon (Si), silicon carbide (SiC), and gallium nitride (GaN) NWs were functionalized with 3

3-Aminopropyltriethoxysilane Functionalization and Biotinylation of 4H-SiC for Immobilization of Streptavidin

June 1, 2012
Author(s)
Elissa H. Williams, Albert Davydov, John A. Schreifels, Mulpuri V. Rao, Abhishek Motayed, Siddarth Sundaresan, Peter Bocchini, Lee J. Richter, Gheorghe Stan, Kristen L. Steffens, Rebecca A. Zangmeister
(0001) 4H-SiC was functionalized with 3-aminopropyltriethoxysilane (APTES) and subsequently biotinylated for the immobilization of streptavidin. Atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), ellipsometry, fluorescence microscopy

Superconformal Ni Electrodeposition using 2-Mercaptobenzimidazole

April 4, 2011
Author(s)
Chang H. Lee, John E. Bonevich, Ugo Bertocci, Kristen L. Steffens, Thomas P. Moffat
Ni superconformal filling of sub-micrometer trenches is demonstrated using a Watts bath containing an inhibitor 2-mercaptobenzimidazole (MBI). Hysteretic voltammetry marks the breakdown of the MBI-induced passive-state coincident with the onset of Ni

Roles of Adhesive and Interfacial Properties on Humidity-induced Failure

February 21, 2010
Author(s)
Kar T. Tan, Christopher C. White, Donald L. Hunston, Kristen L. Steffens, Hatlee Timothy, Kristen Hamilton, Vogt D. Bryan
Adhesion loss due to moisture is a fundamental problem in a large diversity of industries ranging from microelectronics and automotive to aerospace. This study investigates the durability of model adhesive joints consisting of a homologous series of poly(n

A Novel Method to Covalently Functionalize Carbon Nanotubes with Isocyanates

September 30, 2009
Author(s)
Tinh Nguyen, Aline Granier, Kristen L. Steffens, Hajin Lee, Naomi Eidelman, Jonathan W. Martin
We have developed a novel method to covalently functionalize carbon nanotubes (CNTs) that carry free isocyanate (N=C=O) groups. NCO-functionalized CNTs (NCO-fCNTs) are very desirable, because the NCO group is highly reactive with hydrogen-active groups

Impact of Polymer Chemistry on the Durability of Model Adhesives Supported on SiOx Substrates in Humid Environments Using Homologous Series of Poly(n-alkyl methacrylate)s

January 7, 2009
Author(s)
Kar T. Tan, Bryan D. Vogt, Christopher C. White, Kristen Hamilton, Nicholas Wagman, Joshua E. Goldman, Jessica M. Torres, Kristen L. Steffens, Cyril Clerici, Sushil K. Satija, Donald L. Hunston
There are many advantages that structural adhesives can offer compared to the more traditional joining methods, such as welding, bolting, mechanical fastening, etc. However, there are some issues that currently limit the wider application of adhesives. One

Mechanisms of Moisture Attack in Adhesive bonds Exposed to High Humidity

July 23, 2008
Author(s)
Kar T. Tan, Christopher C. White, Cyril Clerici, Donald L. Hunston, Bryan D. Vogt, Sushil K. Satija, Joshua E. Goldman, Kristen L. Steffens
Studies have show that certain adhesive joints exhibit a dramatic loss of strength when exposed to humidities above a certain critical value. Although much is know about this effect, questions still exist. This study combines neutron reflectivity

2-D Imaging of Temperature in CF 4 Plasmas

April 1, 2005
Author(s)
Kristen L. Steffens, Mark A. Sobolewski
Two-dimensional maps of rotational temperature were determined in CF4 plasmas using planar laser-induced fluorescence of CF. Experiments were performed in a capacitively-coupled, parallel plate plasma reactor at pressures from 200mTorr (26.7Pa) to 800mTorr