Modular Sensor Systems for Gas Sensing and Odor Monitoring:  The MOSES Concept

Mitrovics, Jan; Ulmer, Heiko; Weimar, Udo; Göpel, Wolfgang

doi:10.1021/ar970064n

Cited by 69 publications

(44 citation statements)

References 34 publications

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“…The e-nose is an array of eight QMBs and eight semiconducting MOXs (13). Molecular components in the gas phase are allowed to pass by the sensors and thus change some of their physical parameters (here, frequency in the case of the QMBs or conductivity for the MOXs).…”

Section: Resultsmentioning

confidence: 99%

“…The e-nose as a gas sensor array is composed of a chemical sensor system (hardware) and pattern recognition software. The set-up comprises the hybrid Modular Sensor System (MOSES) connected to a headspace sampler for sample preparation (13). The sensor system is equipped with two different modules, each of them based on a different transducer principle.…”

Section: Methodsmentioning

confidence: 99%

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“Electronic nose” detects major histocompatibility complex-dependent prerenal and postrenal odor components

Montag

Frank

Ulmer

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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Mice prefer to mate with individuals expressing different MHC genes from their own. Volatile components presenting MHCdependent odor types are present in urine and can be detected by mice, as shown by extensive behavioral studies. Similar odor types are suspected to influence human behavior as well. Although a recent report indicates that MHC expression influences the ratio of volatile compounds such as phenylacetic acid, so far no other means than studying the behavior of mice or rats has been available to assess odor types. Here, we report the ability of a gas sensor array (referred to as ''electronic nose'') to detect MHCdependent odor types. The electronic nose consists of an array of chemophysical detectors, in our case quartz crystal microbalances and semiconducting metal-oxide sensors that change frequency or conductivity upon binding of very small numbers of individual molecules present in the gas phase of odorous fluids. The pattern of changes is characteristic for a particular smell. Our electronic nose distinguishes the urine odor types of MHC congenic mouse strains, MHC class I mutant mice, and HLA-A2 transgenic mice. In addition, MHC-dependent odor types can be detected in serum. The device also clearly differentiates between individual odor types of human sera from HLA homozygous individuals; however, HLA expression seems to have only a secondary influence. Thus, odor-type research can now be carried out with an objective and fast through-put system independent of behavioral studies.T he principal function of MHC molecules is to present peptides to T cells (1). MHC class I molecules are expressed on the cell membrane of almost all somatic cells. Typically, MHC I molecules present virus-derived peptides of 8-11 aa to virus-specific cytotoxic T cells. MHC class II molecules are expressed on a subset of cells only, most notably on B cells, dendritic cells, and macrophages. Typically, T-helper cells recognize peptides of 12-25 aa derived from antigen presented on B cell MHC II molecules (2). This induces the T cells to produce signals that activate the B cell to produce antibody. MHC I and II molecules have well-defined peptide receptor specificities that enable binding of peptides with certain sequence patterns. MHC genes are extremely polymorphic; there are, for example, more than 180 alleles at the HLA-B locus (3). This polymorphism is reflected in different peptide receptor specificities for each of the allelic products (4). In consequence, T cells from different individuals recognize a different selection of antigen peptides from the very same pathogen. Thus, pathogens can mutate their MHC-presented peptide sequences to escape T cell recognition in an individual; the same mutations, however, are useless for the pathogen in other individuals with different MHC expression. The extreme polymorphism is, therefore, assumed to have evolved to avoid pathogen escape from immune recognition on the species level (5).A driving force for establishment and maintenance of MHC polymorphism is probably the ''surv...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“Electronic nose” detects major histocompatibility complex-dependent prerenal and postrenal odor components

Montag

Frank

Ulmer

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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“…The algorithm was tested against data we have collected using a MOSESII eNose [14] with two sensor modules: an eight-sensor quartz-microbalance (QMB) module, and an eight-sensor metal-oxide (MOX) module. Our eNose, therefore, consists of m ¼ 16 sensors.…”

Section: Methodsmentioning

confidence: 99%

An eNose algorithm for identifying chemicals and determining their concentration

Carmel

Sever

Lancet

et al. 2003

Sensors and Actuators B: Chemical

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We propose an algorithm for use with multisensor systems that is capable of the following: (a) identify an analyte independently of its concentration; (b) estimate the concentration of the analyte, even if the system was not previously exposed to this concentration; (c) tell when an analyte is of a chemical type not previously presented to the system. The algorithm, based upon recent work of Hopfield, uses the multiplicity of sensors explicitly, and is intuitive and easy to implement. We have tested it against real data, and it exhibits high quality performance. #

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“…For dc heating, generated feature vectors tend to be of low dimensionality. Several options are reported in the literature for this situation [2], for instance (1) where is the conductance or resistance of the sensors. However, sometimes additional information may be extracted from the signal transients.…”

Section: B Feature Extractionmentioning

confidence: 99%

“…Soon after their first appearance in the marketplace, these instruments underwent a first step toward size reduction and desktop systems appeared [1]. Nonetheless, the inclusion of automatic headspace samplers and a controlling PC made these instruments only suitable for laboratory purposes.…”

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confidence: 99%

A portable electronic nose based on embedded PC technology and GNU/Linux: hardware, software and applications

et al. 2002

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Abstract-This paper describes a portable electronic nose based on embedded PC technology. The instrument combines a small footprint with the versatility offered by embedded technology in terms of software development and digital communications services. A summary of the proposed hardware and software solutions is provided with an emphasis on data processing. Data evaluation procedures available in the instrument include automatic feature selection by means of SFFS, feature extraction with linear discriminant analysis (LDA) and principal component analysis (PCA), multi-component analysis with partial least squares (PLS) and classification through -NN and Gaussian mixture models. In terms of instrumentation, the instrument makes use of temperature modulation to improve the selectivity of commercial metal oxide gas sensors. Field applications of the instrument, including experimental results, are also presented.

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Modular Sensor Systems for Gas Sensing and Odor Monitoring: The MOSES Concept

Cited by 69 publications

References 34 publications

“Electronic nose” detects major histocompatibility complex-dependent prerenal and postrenal odor components

“Electronic nose” detects major histocompatibility complex-dependent prerenal and postrenal odor components

An eNose algorithm for identifying chemicals and determining their concentration

A portable electronic nose based on embedded PC technology and GNU/Linux: hardware, software and applications

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