A new two-dimensional ion mobility spectrometry approach combined with mass spectrometry has been used to examine ubiquitin ions in the gas phase. In this approach ions are separated in an initial drift tube into conformation types (defined by their collision cross sections) and then a gate is used to introduce a narrow distribution of mobility-separated ions into a second drift tube for subsequent separation. The results show that upon selection a narrow peak shape is retained through the second drift tube. This requires that at 300 K the selected distribution does not interconvert substantially within the broader range of structures associated with the conformation type within the approximately 10-20 ms time scale of these experiments. For the [M + 7H]7+ ion, it appears that many ( approximately 5-10) narrow selections can be made across each of the compact, partially-folded, and elongated conformer types, defined previously (Int. J. Mass Spectrom. 1999, 187, 37-47).
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp056165h | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Design and performance of a magnetic bottle electron spectrometer for high-energy photoelectron spectroscopy.
Rev Sci Instrum
December 2024
SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
We describe the design and performance of a magnetic bottle electron spectrometer (MBES) for high-energy electron spectroscopy. Our design features a 2 m long electron drift tube and electrostatic retardation lens, achieving sub-electronvolt (eV) electron kinetic energy resolution for high energy (several hundred eV) electrons with a close to 4π collection solid angle. A segmented anode electron detector enables the simultaneous collection of photoelectron spectra in high resolution and high collection efficiency modes.
View Article and Find Full Text PDFFlat-Knitted Double-Tube Structure Capacitive Pressure Sensors Integrated into Fingertips of Fully Fashioned Glove Intended for Therapeutic Use.
Sensors (Basel)
November 2024
Institute for Textile Machinery and High Performance Material Technology (ITM), Faculty for Mechanical Science and Engineering, Technische Universität Dresden, 01062 Dresden, Germany.
A therapeutic glove, which enables medical non-professionals to perform physiotherapeutic gripping and holding movements on patients, would significantly improve the healthcare situation in physiotherapy. The glove aims to detect the orthogonal pressure load and provide feedback to the user. The use of textile materials for the glove assures comfort and a good fit for the user.
View Article and Find Full Text PDFThe Development of an Electron Pulse Dilation Photomultiplier Tube Diagnostic Instrument.
Sensors (Basel)
November 2024
College Department of Electronic and Information Engineering, Hengshui University, Hengshui 053000, China.
A new pulse-dilated photomultiplier tube (PD-PMT) with sub-20 ps temporal resolution and associated drivers have been developed for use detection and signal amplification in the inertial confinement fusion (ICF) community. The PD-PMT is coupled to a transmission line output in order to provide a continuous time history of the input signal. Electron pulse dilation provides high-speed detection capabilities by converting incoming signals into a free-electron cloud and manipulating the electron signal with electric and magnetic fields.
View Article and Find Full Text PDFA Method for the Determination of Rate Coefficients for the Formation of Protonated Monomers and Proton Bound Dimers of Volatile Organic Compounds in Air at Ambient Pressure by Ion Mobility Spectrometry.
Anal Chem
December 2024
VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Florida FI-00014, Finland.
Article Synopsis
- - The study measures rate coefficients for reactions involving hydrated protons and various sample vapors to produce protonated monomers and dimers using ion mobility spectrometry with a tandem drift tube.
- - The method involves analyzing ions through two drift regions, adjusting for drift times, and fitting curves to derive accurate rate coefficients for specific compounds like triethyl phosphate and phenylacetate.
- - The proposed technique shows a relative error of 10% and is applicable to a range of substances, indicating it can reliably determine rate coefficients for reactions that form these types of protonated species.
First linac-mounted photon counting detector for image guided radiotherapy: Planar image quality characterization.
Med Phys
November 2024
Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
Article Synopsis
- The study explores the development of a linac-mounted photon-counting detector (PCD) for image-guided radiotherapy (IGRT) that could significantly enhance imaging by improving soft-tissue contrast and spatial resolution compared to traditional flat panel detectors (FPDs).
- Researchers characterized the image quality of the PCD, focusing on parameters like 2D spatial resolution, noise, and contrast, by comparing it with an FPD using various imaging techniques and calibration methods.
- Results showed that the PCD provides a linear energy calibration and better raw contrast in images, suggesting its potential for improved tumor delineation in radiation therapy applications.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!