Jason Amsden

Journal Article International Journal of Mass Spectrometry · January 1, 2025 Mass spectrometers are essential instruments for in situ analysis of planetary materials. Ideally, a space flight mass spectrometer would have a mass range from ∼10 u to at least 500 u to enable analysis of organic molecules to aid in searching for the req ... Full text Cite

Spectral Reconstruction Improvement in a Cycloidal Coded-Aperture Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · May 2024 Spatial aperture coding is a technique used to improve throughput without sacrificing resolution both in optical spectroscopy and sector mass spectrometry (MS). Previous work demonstrated that aperture coding combined with a position-sensitive array detect ... Full text Cite

Proof-of-Concept Vacuum Microelectronic NOR Gate Fabricated Using Microelectromechanical Systems and Carbon Nanotube Field Emitters.

Journal Article Micromachines · April 2023 This paper demonstrates a fully integrated vacuum microelectronic NOR logic gate fabricated using microfabricated polysilicon panels oriented perpendicular to the device substrate with integrated carbon nanotube (CNT) field emission cathodes. The vacuum mi ... Full text Cite

A super-resolution proof of concept in a cycloidal coded aperture miniature mass spectrometer.

Journal Article Rapid communications in mass spectrometry : RCM · January 2023 RationaleHigher resolution in fieldable mass spectrometers (MS) is desirable in space flight applications to enable resolving isobaric interferences at m/z < 60 u. Resolution in portable cycloidal MS coupled with array detectors could be improved ... Full text Cite

Design considerations for a cycloidal mass analyzer using a focal plane array detector.

Journal Article Journal of mass spectrometry : JMS · July 2022 With the advent of technologies such as ion array detectors and high energy permanent magnet materials, there is renewed interest in the unique focusing properties of the cycloidal mass analyzer and its ability to enable small, high-resolution, and high-se ... Full text Cite

Virtual-slit focusing in a cycloidal mass spectrometer – A proof of concept

Journal Article International Journal of Mass Spectrometry · December 1, 2021 This work demonstrates a novel approach to mass spectrometry using the “virtual-slit” created by the small, localized volume from which ions are generated by localized ionization techniques such as laser ionization of particles and surfaces, and spark ioni ... Full text Cite

The Long Neglected Cycloidal Mass Analyzer.

Journal Article Analytical chemistry · August 2021 In 1938, Walker Bleakney and John A. Hipple first described the cycloidal mass analyzer as the only mass analyzer configuration capable of "perfect" ion focusing. Why has their geometry been largely neglected for many years and how might it earn a respecta ... Full text Cite

Improving the Performance of a Cycloidal Coded-Aperture Miniature Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · February 2021 Cycloidal sector mass analyzers have, in principle, perfect focusing due to perpendicularly oriented uniform electric and magnetic fields, making them ideal candidates for incorporation of spatially coded apertures. We have previously demonstrated a proof- ... Full text Cite

Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers

Journal Article International Journal of Mass Spectrometry · November 1, 2020 This work compares the coded aperture imaging performance of thermionic filament and carbon nanotube (CNT) field emitter-based electron sources in cycloidal-coded aperture mass spectrometers. The use of spatially coded apertures in mass spectrometry enable ... Full text Cite

A novel sector mass spectrograph design for high-order coded aperture Mass Spectrometry with stigmatic aberration correction

Journal Article International Journal of Mass Spectrometry · September 1, 2020 Previous works experimentally demonstrated that the application of spatially-coded apertures to simple sector mass spectrographs can result in increased signal intensity while maintaining spectral resolution comparable to that of a conventional slit apertu ... Full text Cite

High current density electron emission from an electrodeposited metal nanowire array

Journal Article Journal of Vacuum Science and Technology B · July 1, 2020 High-current electron field emitters are of interest for many applications, but state-of-the-art devices suffer from limitations such as high turn-on macroscopic field, low macroscopic current density, poor emission stability, and short lifetime. Field emi ... Full text Cite

Prototype coded aperture miniature mass spectrometer for environmental sensing

Conference AQM 2019 - Air Quality Measurement Methods and Technology Conference 2019 · January 1, 2019 © 2019 Air and Waste Management Association. All rights reserved. In summary, this paper shows the design and initial performance characterization of a coded aperture miniature mass spectrometer for environmental sensing (CAMMS-ES). CAMMS-ES incorporates s ... Cite

Prototype coded aperture miniature mass spectrometer for environmental sensing

Conference AQM 2019 - Air Quality Measurement Methods and Technology Conference 2019 · January 1, 2019 In summary, this paper shows the design and initial performance characterization of a coded aperture miniature mass spectrometer for environmental sensing (CAMMS-ES). CAMMS-ES incorporates spatial aperture coding to break the throughput vs. resolution trad ... Cite

Proof of Concept Coded Aperture Miniature Mass Spectrometer Using a Cycloidal Sector Mass Analyzer, a Carbon Nanotube (CNT) Field Emission Electron Ionization Source, and an Array Detector.

Journal Article Journal of the American Society for Mass Spectrometry · February 2018 Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tr ... Full text Cite

Effects of Magnetic and Electric Field Uniformity on Coded Aperture Imaging Quality in a Cycloidal Mass Analyzer.

Journal Article Journal of the American Society for Mass Spectrometry · February 2018 Cycloidal mass analyzers are unique sector mass analyzers as they exhibit perfect double focusing, making them ideal for incorporating spatial aperture coding, which can increase the throughput of a mass analyzer without affecting the resolving power. Howe ... Full text Cite

A miniature electron ionization source fabricated using microelectromechanical systems (MEMS) with integrated carbon nanotube (CNT) field emission cathodes and low-temperature co-fired ceramics (LTCC)

Journal Article International Journal of Mass Spectrometry · November 1, 2017 The use of microelectromechanical systems (MEMS) components in miniature mass spectrometers is particularly attractive due to their small size and scalable manufacturing capability. Our group has pioneered the development of miniature electron ionization s ... Full text Cite

Temperature Dependence and Impedance Characteristics of Hybrid Solar Cells Based on Poly(phenylene vinylene): ZnO Nanoparticles with Added Surfactants

Journal Article IEEE Journal of Photovoltaics · July 1, 2017 A recent study has shown that the use of a semiconducting surfactant in hybrid bulk heterojunction solar cells based on poly[2-methoxy-5-(3′,7′-dimethyloctyloxyl)-1,4-phenylene vinylene] and zinc oxide significantly increases their performance. To further ... Full text Cite

Coded Apertures in Mass Spectrometry.

Journal Article Annual review of analytical chemistry (Palo Alto, Calif.) · June 2017 The use of coded apertures in mass spectrometry can break the trade-off between throughput and resolution that has historically plagued conventional instruments. Despite their very early stage of development, coded apertures have been shown to increase thr ... Full text Cite

Improved Performance of Field Emission Vacuum Microelectronic Devices for Integrated Circuits

Journal Article IEEE Transactions on Electron Devices · September 1, 2016 The movement from discrete transistors to integrated silicon circuits led to the rapid evolution of microscale electronics, but there has been no equivalent transition for the vacuum tube transistor. Difficulty integrating devices at microscales has hinder ... Full text Cite

Compatibility of Spatially Coded Apertures with a Miniature Mattauch-Herzog Mass Spectrograph.

Journal Article Journal of the American Society for Mass Spectrometry · April 2016 In order to minimize losses in signal intensity often present in mass spectrometry miniaturization efforts, we recently applied the principles of spatially coded apertures to magnetic sector mass spectrometry, thereby achieving increases in signal intensit ... Full text Cite

Towards the fabrication of biohybrid silk fibroin materials: Entrapment and preservation of chloroplast organelles in silk fibroin films

Journal Article RSC Advances · January 1, 2016 Chloroplasts extracted from spinach leaves were entrapped in B. mori silk fibroin films to investigate the maintenance of their photosynthetic activity in a dry environment. Chloroplast stability was studied under various storage conditions (different temp ... Full text Cite

Chemical ionization mass spectrometry using carbon nanotube field emission electron sources.

Journal Article Journal of the American Society for Mass Spectrometry · November 2015 A novel chemical ionization (CI) source has been developed based on a carbon nanotube (CNT) field emission electron source. The CNT-based electron source was evaluated and compared with a standard filament thermionic electron source in a commercial explosi ... Full text Cite

Achieving Excellence in Graduate Research: A Guide for New Graduate Students.

Journal Article Advanced science (Weinheim, Baden-Wurttemberg, Germany) · October 2015 A mentoring guide for incoming graduate students has been developed to minimize the time spent reiterating general guidance and "norms" that need to be instilled in new graduate students. This allows principal investigators and senior researchers to ... Full text Cite

Order of Magnitude Signal Gain in Magnetic Sector Mass Spectrometry Via Aperture Coding.

Journal Article Journal of the American Society for Mass Spectrometry · September 2015 Miniaturizing instruments for spectroscopic applications requires the designer to confront a tradeoff between instrument resolution and instrument throughput [and associated signal-to-background-ratio (SBR)]. This work demonstrates a solution to this trade ... Full text Cite

Two-dimensional aperture coding for magnetic sector mass spectrometry.

Journal Article Journal of the American Society for Mass Spectrometry · February 2015 In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would ... Full text Cite

Platform for integrated vacuum microelectronic circuits

Conference IEEE International Vacuum Electronics Conference, IVEC 2014 · January 1, 2014 Vacuum devices are preferred to solid-state for applications requiring radiation stability, a wide range in operating temperature, or high power at high frequency. However, difficulties associated with integrating these devices on the microscale have limit ... Full text Cite

Implantable resorbable micro-prism arrays for real-time drug release monitoring

Conference 2012 Conference on Lasers and Electro-Optics, CLEO 2012 · December 6, 2012 We present a free-standing micro-prism array device entirely constituted by silk protein showing enhanced optical reflectivity, which can be used to monitor drug delivery while slowly degrading to surrounding tissues with no adverse biological effects. © 2 ... Cite

Implantable, multifunctional, bioresorbable optics.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · November 2012 Advances in personalized medicine are symbiotic with the development of novel technologies for biomedical devices. We present an approach that combines enhanced imaging of malignancies, therapeutics, and feedback about therapeutics in a single implantable, ... Full text Cite

Polymer-nanoparticle hybrid solar cell

Conference Technical Digest - 2012 17th Opto-Electronics and Communications Conference, OECC 2012 · October 23, 2012 The fabrication of polymer solar cells on large-area, flexible substrates offers the possibility for developing lower-cost commercial solar cells, although their efficiency is still quite low compared to other thin film solar cells. Here, we have investiga ... Full text Cite

Parallel pool analysis of transient spectroscopy reveals origins of and perspectives for ZnO hybrid solar cell performance enhancement using semiconducting surfactants

Journal Article Journal of Physical Chemistry Letters · September 20, 2012 Recently, the performance of ZnO nanocrystals as an electron acceptor in a solar cell device was significantly increased by a semiconducting surfactant. Here we show, using transient absorption spectroscopy and a parallel pool analysis, that changes in the ... Full text Cite

Low-threshold blue lasing from silk fibroin thin films

Journal Article Applied Physics Letters · August 27, 2012 Silk is a natural biocompatible material that can be integrated in a variety of photonic systems and optoelectronic devices. The silk replication of patterned substrates with features down to tens of nanometers is exploited to realize highly transparent, m ... Full text Cite

Implantable resorbable micro-prism arrays for real-time drug release monitoring

Conference CLEO: Science and Innovations, CLEO_SI 2012 · January 1, 2012 We present a free-standing micro-prism array device entirely constituted by silk protein showing enhanced optical reflectivity, which can be used to monitor drug delivery while slowly degrading to surrounding tissues with no adverse biological effects. © O ... Full text Cite

Effect of nanoscale SubPc interfacial layer on the performance of inverted polymer solar cells based on P3HT/PC71BM

Journal Article ACS Applied Materials and Interfaces · November 23, 2011 The effect of a nanoscale boron subphthalocyanine chloride (SubPc) interfacial layer on the performance of inverted polymer solar cells based on poly (3-hexyl thiophene) (P3HT) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) was studied. When a 1 n ... Full text Cite

Rapid nano impact printing of silk biopolymer thin films

Journal Article Journal of Micromechanics and Microengineering · November 1, 2011 In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of g ... Full text Cite

Area and light intensity dependence of buffer layers on P3HT: PCBM solar cells

Journal Article Journal of the Korean Physical Society · August 12, 2011 Polymer solar cells have been fabricated with buffer layers to enhance the charge extraction toward the electrodes. We investigated the active area and the light intensity dependences in poly (3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl e ... Full text Cite

Integration of silk protein in organic and light-emitting transistors

Journal Article Organic Electronics · January 1, 2011 We present the integration of a natural protein into electronic and optoelectronic devices by using silk fibroin as a thin film dielectric in an organic thin film field-effect transistor (OFET) ad an organic light emitting transistor device (OLET) structur ... Full text Cite

Enhanced photovoltaic performance of ZnO nanoparticle/poly(phenylene vinylene) hybrid photovoltaic cells by semiconducting surfactant

Journal Article Organic Electronics · January 1, 2011 Hybrid films of ZnO nanoparticles and poly[2-methoxy-5-(3′,7′- dimethyloctyloxyl)-1,4-phenylene vinylene] (MDMO-PPV) were investigated as a model hybrid bulk heterojunction (HBHJ) photovoltaic cell which combines the simple processability and excellent ele ... Full text Cite

Ultra-sensitive infrared spectroscopy of proteins with collective excitations of nanoplasmonic arrays

Conference Optics InfoBase Conference Papers · December 1, 2010 Short interaction lengths limit the application of infrared absorption spectroscopy to the study monolayer thickness films. We employ periodic infrared antenna arrays to obtain 104- 105 enhancement of protein absorption signals corresponding to zepto-mole ... Cite

Biosensing with colorimetric signatures of deterministic aperiodic metal nanoparticle arrays

Conference Optics InfoBase Conference Papers · December 1, 2010 A novel optical sensing technique based on distinctive colorimetric signatures and spectral shifts of deterministic aperiodic arrays is demonstrated by protein monolayer sensing in the visible spectral range using inexpensive dark-field spectroscopy and au ... Cite

Radiative engineering of nanoantenna arrays for ultra-sensitive vibrational spectroscopy of proteins

Conference Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2010 Infrared absorption spectroscopy offers direct access to the vibrational signatures of molecular structure. Although absorption cross sections are nearly 10 orders of magnitude larger than the Raman cross sections, they are small in comparison with those o ... Full text Cite

Rapid nanoimprinting of doped silk films for enhanced fluorescent emission.

Journal Article Advanced materials (Deerfield Beach, Fla.) · November 2010 Full text Cite

Metamaterial silk composites at terahertz frequencies.

Journal Article Advanced materials (Deerfield Beach, Fla.) · August 2010 Full text Cite

Formation of colorimetric fingerprints on nano-patterned deterministic aperiodic surfaces

Journal Article Optics Express · July 5, 2010 Periodic gratings and photonic bandgap structures have been studied for decades in optical technologies. The translational invariance of periodic gratings gives rise to well-known angular and frequency filtering of the incident radiation resulting in well- ... Full text Cite

Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · July 2010 Light scattering phenomena in periodic systems have been investigated for decades in optics and photonics. Their classical description relies on Bragg scattering, which gives rise to constructive interference at specific wavelengths along well defined prop ... Full text Cite

Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics.

Journal Article Nature materials · June 2010 Electronics that are capable of intimate, non-invasive integration with the soft, curvilinear surfaces of biological tissues offer important opportunities for diagnosing and treating disease and for improving brain/machine interfaces. This article describe ... Full text Cite

Rapid nanoimprinting of silk fibroin films for biophotonic applications.

Journal Article Advanced materials (Deerfield Beach, Fla.) · April 2010 Full text Cite

Ultra-sensitive infrared spectroscopy of proteins with collective excitations of nanoplasmonic arrays

Conference Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 · January 1, 2010 Short interaction lengths limit the application of infrared absorption spectroscopy to the study monolayer thickness films. We employ periodic infrared antenna arrays to obtain 104-105 enhancement of protein absorption signals corresponding to zepto-mole s ... Full text Cite

Large area spraying of terahertz materials on free-standing biocompatible silk films

Conference Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop · January 1, 2010 We report the first large area metamaterials patterned on free-standing biocompatible silk substrates using shadow mask evaporation techniques. The as-fabricated silk metamaterial composites show strong electromagnetic resonant responses at terahertz frequ ... Full text Cite

Silk fibroin biosensor based on imprinted periodic nanostructures

Conference Optics InfoBase Conference Papers · December 1, 2009 This paper presents a label free colorometric sensor fabricated by rapidly imprinting k fibroin thin films with periodic nanoholes. The fabricated sensor is sensitive to index riations of Δn = 0.007. silva. © 2009 Optical Society of America. ... Cite

Erratum: Silicon electronics on silk as a path to bioresorbable, implantable devices (Applied Physics Letters (2009) 95 (133701))

Journal Article Applied Physics Letters · December 1, 2009 Full text Cite

Bioactive "self-sensing" optical systems

Journal Article Applied Physics Letters · December 1, 2009 Free-standing silk films are useful materials to manufacture nanopatterned optical elements and to immobilize bio-dopants such as enzymes while maintaining their biological activity. These traits were combined by incorporating hemoglobin into free-standing ... Full text Cite

Silk fibroin biosensor based on imprinted periodic nanostructures

Conference 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 This paper presents a label free colorometric sensor fabricated by rapidly imprinting silk fibroin thin films with periodic nanoholes. The fabricated sensor is sensitive to index variations of Δn = 0.007. ©2009 Optical Society of America. ... Cite

Ultra-sensitive vibrational spectroscopy of protein monolayers with plasmonic nanoantenna arrays.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · November 2009 Infrared absorption spectroscopy enabling direct access to vibrational fingerprints of the molecular structure is a powerful method for functional studies of bio-molecules. Although the intrinsic absorption cross-sections of IR active modes of proteins are ... Full text Cite

Spectral analysis of induced color change on periodically nanopatterned silk films.

Journal Article Optics express · November 2009 We demonstrate controllable structural color based on periodic nanopatterned 2D lattices in pure protein films of silk fibroin. We show here periodic lattices in silk fibroin films with feature sizes of hundreds of nanometers that exhibit different colors ... Full text Cite

Silicon electronics on silk as a path to bioresorbable, implantable devices

Journal Article Applied Physics Letters · October 12, 2009 Many existing and envisioned classes of implantable biomedical devices require high performance electronics/sensors. An approach that avoids some of the longer term challenges in biocompatibility involves a construction in which some parts or all of the sy ... Full text Cite

Biocompatible silk printed optical waveguides

Journal Article Advanced Materials · June 19, 2009 A method for fabrication of microscale biopolymer waveguides with controlled structure and composition, through direct assembly of a highly concentrated aqueous solution of pure silk-fibroin protein was reported. The study have also demonstrated the 2D and ... Full text Cite

Silk fibroin biosensor based on imprinted periodic nanostructures

Conference Optics InfoBase Conference Papers · January 1, 2009 This paper presents a label free colorometric sensor fabricated by rapidly imprinting k fibroin thin films with periodic nanoholes. The fabricated sensor is sensitive to index riations of Δn = 0.007. silva. © 2009 Optical Society of America. ... Full text Cite

Different structural changes occur in blue- and green-proteorhodopsins during the primary photoreaction.

Journal Article Biochemistry · November 2008 We examine the structural changes during the primary photoreaction in blue-absorbing proteorhodopsin (BPR), a light-driven retinylidene proton pump, using low-temperature FTIR difference spectroscopy. Comparison of the light-induced BPR difference spectrum ... Full text Cite

Nitrous oxide vibrational energy relaxation is a probe of interfacial water in lipid bilayers

Journal Article Journal of Physical Chemistry B · October 9, 2008 Ultrafast infrared spectroscopy of N2O is shown to be a sensitive probe of hydrophobic and aqueous sites in lipid bilayers. Distinct rates of VER of the ν3 antisymmetric stretching mode of N 2O can be distinguished for N2O solvated in the acyl tail, interf ... Full text Cite

Protonation state of Glu142 differs in the green- and blue-absorbing variants of proteorhodopsin.

Journal Article Biochemistry · March 2008 Proteorhodopsins are a recently discovered class of microbial rhodopsins, ubiquitous in marine bacteria. Over 4000 variants have thus far been discovered, distributed throughout the oceans of the world. Most variants fall into one of two major groups, gree ... Full text Cite

Ultrafast vibrational relaxation of liquid H2O following librational combination band excitation

Journal Article Chemical Physics · November 15, 2007 Dispersed pump-probe responses excited by ∼165 fs pulses resonant with the bend-libration combination band in neat H2O centered at 2130 cm-1 are reported. This is the first IR pump-probe study of the energy relaxation dynamics in this region of the liquid ... Full text Cite

Subpicosecond protein backbone changes detected during the green-absorbing proteorhodopsin primary photoreaction

Journal Article Journal of Physical Chemistry B · October 11, 2007 Recent studies demonstrate that photoactive proteins can react within several picoseconds to photon absorption by their chromophores. Faster subpicosecond protein responses have been suggested to occur in rhodopsin-like proteins where retinal photoisomeriz ... Full text Cite

Conformational changes in the photocycle of Anabaena sensory rhodopsin: absence of the Schiff base counterion protonation signal.

Journal Article The Journal of biological chemistry · June 2006 Anabaena sensory rhodopsin (ASR) is a novel microbial rhodopsin recently discovered in the freshwater cyanobacterium Anabaena sp. PCC7120. This protein most likely functions as a photosensory receptor as do the related haloarchaeal sensory rhodopsins. Howe ... Full text Cite

Conformational dynamics of amyloid beta-protein assembly probed using intrinsic fluorescence.

Journal Article Biochemistry · October 2005 Formation of toxic oligomeric and fibrillar structures by the amyloid beta-protein (Abeta) is linked to Alzheimer's disease (AD). To facilitate the targeting and design of assembly inhibitors, intrinsic fluorescence was used to probe assembly-dependent cha ... Full text Cite

Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction.

Journal Article Biochemistry · July 2004 Proteorhodopsin (PR), found in marine gamma-proteobacteria, is a newly discovered light-driven proton pump similar to bacteriorhodopsin (BR). Because of the widespread distribution of proteobacteria in the worldwide oceanic waters, this pigment may contrib ... Full text Cite