Engineering topics

Clowers, Brian H

Publications and source records attributed to Clowers, Brian H.

3 records

DOE OSTI2013

Direct Real-Time Detection of RDX Vapors Under Ambient Conditions

The results in this manuscript represent a demonstration of RDX vapor detection in real time at ambient temperature without sample pre-concentration. The detection of vapors from the low volatility explosive compound RDX was achieved through selective atmospheric pressure chemical ionization using nitrate reactant ions (NO3-), and NO3-•HNO3 adducts generated in an electrical discharge source. The RDX vapors were ionized in a reaction region, which provided a variable (up to several seconds) reaction time. The reaction times were controlled by either flow in an atmospheric flow tube (AFT) or by electric field in an atmospheric drift tube (ADT). Both AFT and ADT were interfaced to a quadrupole mass spectrometer for ion detection and identification. Recorded signals were observed for RDX concentrations below 25 ppq using selected ion monitoring (SIM) of the RDX-nitrate adduct at m/z 284.

Ewing, Robert G↗

DOE OSTI2010

An efficient data format for mass spectrometry based proteomics

The diverse range of mass spectrometry (MS) instrumentation along with corresponding proprietary and non-proprietary data formats has generated a proteomics community driven call for a standardized format to facilitate management, processing, storing, visualization, and exchange of both experimental and processed data. To date, significant efforts have been extended towards standardizing XML-based formats for mass spectrometry data representation, despite the recognized inefficiencies associated with storing large numeric datasets in XML. The proteomics community has periodically entertained alternate strategies for data exchange, e.g., using a common application programming interface or a database-derived format. However these efforts have yet to garner significant attention, mostly because they haven’t illustrated significant performance benefits over existing standards, but also due to issues such as extensibility to multi-dimensional separation systems, robustness of operation, and incomplete or mismatched vocabulary. Here, we describe a format based on standard database principles that offers multiple benefits over existing formats in terms of storage size, ease of processing, data retrieval times and extensibility to accommodate multi-dimensional separation systems.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2010

Proteomics Development and Application for Bioforensics

Proteomics is a relatively new scientific discipline dedicated to the comprehensive study of the protein composition of biological systems. While genomic sequencing is an invaluable tool for bioforensic sample identification, proteomics complements genomics in that the genes present in an organism code for the proteins that can be present in a microorganism. Many proteins are conserved for general identification while other protein expression varies with environment/growth state/growth conditions (i.e. not all proteins are expressed at any given time or condition) providing additional information beyond genomic analysis. This expression specificity and the relative stability of proteins with respect to genetic material make them attractive targets for microorganism identification and forensic applications to complement genomic approaches. Proteomic analysis depends upon the availability of genome sequences of the relevant organisms or their near relatives. The known amino acid sequences for potential proteins within the database can be compared to amino acid sequences of actual proteins present in a sample as determined with high mass accuracy by mass spectrometry for identification of the proteins in the sample. With the development of technology for rapid genome sequencing of organisms, the known protein database is growing, supporting improved identification of the proteins present in a sample. Recent developments in mass spectrometry instrumentation and microbial sequencing are leading to an increased growth in application of proteomics to microbiology, pathogen detection, disease diagnosis and microbial forensics as well as other biological disciplines. Mass spectrometry analysis does not require a priori knowledge of the sample or expected targets to gain meaningful.

59 BASIC BIOLOGICAL SCIENCES↗