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MIDDLETON, WI, United States

Prosa T.J.,Imago Scientific Instruments | Keeney S.K.,Prairie Technologies, Inc. | Kelly T.F.,Imago Scientific Instruments
Journal of Microscopy | Year: 2010

Pulsed-laser atom-probe tomography is used to compare the field-evaporation mass spectrum and spatial distribution of molecular fragments from various poly(3-alkylthiophene) films deposited on sharpened aluminium specimen carriers using two different deposition methods. Films deposited via a modified solution-cast methodology yield small fragments with a uniform structural morphology whereas films deposited via an electrospray ionization methodology yield a wide range of fragments with a very non-uniform structural morphology. The main field-evaporated chemical species identified for both deposition types were, in order of typical relative abundance, C2H5+, CH3+, C2H4+, followed by C3H7,8+/SC + and SCH+. Thick electrospray depositions allowed investigation of the influence of laser-pulse energy on the analysis. Evidence is presented supporting the presence of a critical laser-pulse energy whereby changes in film morphology are signalled by the appearance of a new mass fragment at 190 Da. © 2009 The Royal Microscopical Society.


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 146.07K | Year: 2001

DESCRIPTION (provided by applicant): Recent developments in near-field instrumentation have provided PRAIRIE TECHNOLOGIES with the necessary understanding to develop a multi-mode confocal microscope that will integrate confocal microscopy with simultaneous high-speed fluorescence measurements as well as sub-diffraction resolution imaging. This powerful new tool will revolutionize scientists' ability to study neuronal function and dysfunction in living systems. In phase I we will build and test an alpha prototype by integrating a high-speed fluorescence detection path into our existing confocal microscope. In phase II, we will use the knowledge gained in this phase I feasibility to design and build a commercial simultaneous near-field and confocal imaging system. The resultant product will permit the scientist to address significant questions concerning ion fluxes, synaptic transmission and the molecular nature of learning and memory. PROPOSED COMMERCIAL APPLICATION: Not Available


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 749.65K | Year: 1998

DESCRIPTION (Adapted from applicant's abstract): Our understanding of the molecular control of neuronal function and synaptic transmission is limited because studies are performed using high resolution molecular genetic approaches within the limits of diffraction limited optical microscopy. To increase the understanding of CNS function, it is essential that we can visualize the action of microdomains of molecules or even single molecules in living systems. Near-Field Scanning Optical Microscopy (NSOM) has revolutionized optical microscopy in the physical sciences by permitting investigations of single molecules with visible wavelengths of light. Recently, the applicant's collaborator, Dr. Haydon, has made modifications to such instrumentation and has demonstrated its utility in biological studies of living systems. The goal of this Phase I proposal is to determine the feasibility of developing turn-key instrumentation for sub- diffraction resolution of living cells. They will develop and evaluate an automated photon feedback (PDF) instrument that was recently invented at Iowa State University, to achieve sub-diffraction optical resolution for studies of living cells. The longer term objective (Phases I and II) is to develop an integrated near-field confocal microscope for biological applications. $ = TOTAL AWARD AMTS & NOT LIMITED TO PORTION OF PROJECT RELATED TO SUBJECT OF SEARCH SUBPROJECT $ = TOTAL AWARD AMOUNT DIVIDED BY NUMBER OF SUBPROJECTS SOURCE: CRISP FORMAT F FY 97 LAST UPDATE 04-07-98 1QUERY 1536 ID SEARCH 06/01/98 PAGE 480 --PROJECT NUMBER......1 R43 MH58042-01 INVESTIGATOR NAME/ADDRESS FY 97 PETERS, RICHARD IRG/INTRAMURAL UNIT..MHSB AAAS SCIENCE PUBLICATIONS INC AWARD AMOUNT......... $115,000 1200 NEW YORK AVE, NW WASHINGTON, DC 20005 PERFORMING ORGANIZATION: AAAS SCIENCE PUBLICATIONS, INC. TITLE DEVELOPMENT OF A NEURO-AIDS WEB SITE ABSTRACT: The proposed Phase I project is a demonstration of feasibility of an economically self-sustaining World Wide Web site to facilitate information exchange within and across critical areas of science and encourage new scientific collaborations. The proposed test of feasibility will focus on two crucial questions regarding communication on the World Wide Web: Can authoritative, reliable information be provided through this medium? Will such a medium prove to be a useful forum for the scientific community? Because it is a multidisciplinary field crucial to the AIDS epidemic and remains underserved, neuro-AIDS has been selected for the Phase I test of feasibility. A Web site will be developed focusing on key questions in neuro-AIDS, as selected by a Scientific Advisory Panel of outstanding investigators in the field. The site will be aimed at researchers currently in neuro-AIDS, in other AIDS-related areas, non-AIDS researchers with neuro-AIDS-relevant expertise, clinicians who treat individuals living with HIV, and young investigators in fields such as neuroscience or molecular biology who may consider neuro-AIDS research.


Grant
Agency: Department of Health and Human Services | Branch: | Program: STTR | Phase: Phase I | Award Amount: 427.89K | Year: 2002

Reading the conformational state of membrane proteins is central to understanding their role in cell signaling, to using them as sensor elements and for screening candidate drug compounds that are targeted toward this important class of biomolecules. While the patch clamp technique for doing this is ubiquitous, it does have significant limitations: two electrodes are required to measure current flow, the GW input impedance combines with unavoidable stray capacitance to limit the amplifier's bandwidth (typically to -10 kHz), and the GW seal required at the cell membrane precludes scanning to image both distribution and dynamics of membrane proteins. To address these limitations, we will develop near-field probes to confine high-frequency excitation to sub-wavelength proportions, enabling interaction with single membrane proteins. Since there are inherent dielectric contrast mechanisms available in protein-lipid systems, these can be used at high frequencies to provide a new method of protein readout. The overall goal of this work is to build scanning protein probes that can image distribution and dynamics of ion channel activity simultaneously.


Grant
Agency: Department of Health and Human Services | Branch: | Program: STTR | Phase: Phase II | Award Amount: 1.20M | Year: 2005

DESCRIPTION (provided by applicant): Reading the conformational state of membrane proteins is central to understanding their role ir cell signaling, to using them as sensor elements and for screening candidate drug compounds that are targeted toward this important class of biomolecules. While the patch clamp technique for doing this is ubiquitous, it does have significant limitations: two electrodes are required to measure current flow, the gigaohm input impedance combines with unavoidable stray capacitance to limit the amplifier's bandwidth (typically to -10 kHz), and the gigaohmseal required at the cell membrane precludes scanning to image both distribution and dynamics of membrane proteins. To address these limitations, we will develop near-field probes, readouts, positioners and software to make a prototype system that confines high-frequency excitation to sub-wavelength proportions, enabling interaction with single membrane proteins. Since there are inherent dielectric contrast mechanisms available in protem-lipid systems, these can be used at high frequencies to provide a new method of protein readout. We have succeeded in demonstrating simultaneous recordings from alpha-hemolysin blocked by beta-cyclodextrin using both a conventional patch-clamp amplifier and a microwave source and detector. The microwave probe has the advantage of approximately 1 MHz bandwidth, so it is able to resolve more temporal detail than the patch clamp. Furthermore, the microwave probe is sensitive to changes both in conductance and capacitance, i.e. the movement of charge groups in the channel. This opens the door to probing for the first time changes in conformation that do rot otherwise change channel conductance. Finally, the microwave probe by its nature does not require a gigaohm seal (in fact, its impedance is 50 ohms), enabling us to realize a scanning electrode that can map both distribution and dynamics of channel activity. We will develop this prototype in conjunction with a collaborator in neuroscience so that the feedback gained from a field test will be used in making the system commercially viable.

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