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Decision tree-based identification of Staphylococcus aureus via infrared spectral analysis of ambient gas. Anal Bioanal Chem 2021; 414:1049-1059. [PMID: 34686896 PMCID: PMC8724094 DOI: 10.1007/s00216-021-03729-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 09/10/2021] [Accepted: 10/11/2021] [Indexed: 12/02/2022]
Abstract
In this study, eight types of bacteria were cultivated, including Staphylococcus aureus. The infrared absorption spectra of the gas surrounding cultured bacteria were recorded at a resolution of 0.5 cm−1 over the wavenumber range of 7500–500 cm−1. From these spectra, we searched for the infrared wavenumbers at which characteristic absorptions of the gas surrounding Staphylococcus aureus could be measured. This paper reports two wavenumber regions, 6516–6506 cm−1 and 2166–2158 cm−1. A decision tree–based machine learning algorithm was used to search for these wavenumber regions. The peak intensity or the absorbance difference was calculated for each region, and the ratio between them was obtained. When these ratios were used as training data, decision trees were created to classify the gas surrounding Staphylococcus aureus and the gas surrounding other bacteria into different groups. These decision trees show the potential effectiveness of using absorbance measurement at two wavenumber regions in finding Staphylococcus aureus.
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Laser-Plasma Spatiotemporal Cyanide Spectroscopy and Applications. Molecules 2020; 25:molecules25030615. [PMID: 32023810 PMCID: PMC7037963 DOI: 10.3390/molecules25030615] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 11/17/2022] Open
Abstract
This article reports new measurements of laser-induced plasma hypersonic expansion measurements of diatomic molecular cyanide (CN). Focused, high-peak-power 1064 nm Q-switched radiation of the order of 1 TW/cm 2 generated optical breakdown plasma in a cell containing a 1:1 molar gas mixture of N 2 and CO 2 at a fixed pressure of 1.1 × 10 5 Pascal and in a 100 mL/min flow of the mixture. Line-of-sight (LOS) analysis of recorded molecular spectra indicated the outgoing shockwave at expansion speeds well in excess of Mach 5. Spectra of atomic carbon confirmed increased electron density near the shockwave, and, equally, molecular CN spectra revealed higher excitation temperature near the shockwave. Results were consistent with corresponding high-speed shadowgraphs obtained by visualization with an effective shutter speed of 5 nanoseconds. In addition, LOS analysis and the application of integral inversion techniques allow inferences about the spatiotemporal plasma distribution.
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Selvaraj R, Vasa NJ, Shiva Nagendra SM. Off-resonant photoacoustic spectroscopy for analysis of multicomponent gas mixtures at high concentrations using broadband vibrational overtones of individual gas species. APPLIED OPTICS 2019; 58:4118-4126. [PMID: 31158168 DOI: 10.1364/ao.58.004118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
The broadband photoacoustic spectroscopy (PAS) technique is proposed and demonstrated for measurement of CH4, CO2, and H2O vapor in the 1.6 to 2.0 μm wavelength region. The wide spectrum of a supercontinuum light source is used to cover broadband absorption bands of multiple gas species. This sensor works in the off-resonant frequency of the designed photoacoustic cell and exhibits a wide concentration measurement range of parts per billion by volume (ppb-v) to 100%. The PAS sensor is further tested in real time by measuring the concentration of CO2, CH4, and H2O vapor in biogas plants.
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Henderson B, Khodabakhsh A, Metsälä M, Ventrillard I, Schmidt FM, Romanini D, Ritchie GAD, te Lintel Hekkert S, Briot R, Risby T, Marczin N, Harren FJM, Cristescu SM. Laser spectroscopy for breath analysis: towards clinical implementation. APPLIED PHYSICS. B, LASERS AND OPTICS 2018; 124:161. [PMID: 30956412 PMCID: PMC6428385 DOI: 10.1007/s00340-018-7030-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/19/2018] [Indexed: 05/08/2023]
Abstract
Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status of a patient and disease diagnosis, since it is non-invasive and fast. Numerous studies have already demonstrated the benefit of breath analysis in clinical settings/applications and encouraged multidisciplinary research to reveal new insights regarding the origins, pathways, and pathophysiological roles of breath components. Many breath analysis methods are currently available to help explore these directions, ranging from mass spectrometry to laser-based spectroscopy and sensor arrays. This review presents an update of the current status of optical methods, using near and mid-infrared sources, for clinical breath gas analysis over the last decade and describes recent technological developments and their applications. The review includes: tunable diode laser absorption spectroscopy, cavity ring-down spectroscopy, integrated cavity output spectroscopy, cavity-enhanced absorption spectroscopy, photoacoustic spectroscopy, quartz-enhanced photoacoustic spectroscopy, and optical frequency comb spectroscopy. A SWOT analysis (strengths, weaknesses, opportunities, and threats) is presented that describes the laser-based techniques within the clinical framework of breath research and their appealing features for clinical use.
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Affiliation(s)
- Ben Henderson
- Trace Gas Research Group, Molecular and Laser Physics, IMM, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Amir Khodabakhsh
- Trace Gas Research Group, Molecular and Laser Physics, IMM, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Markus Metsälä
- Department of Chemistry, University of Helsinki, PO Box 55, 00014 Helsinki, Finland
| | | | - Florian M. Schmidt
- Department of Applied Physics and Electronics, Umeå University, 90187 Umeå, Sweden
| | - Daniele Romanini
- University of Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - Grant A. D. Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ UK
| | | | - Raphaël Briot
- University of Grenoble Alpes, CNRS, TIMC-IMAG, 38000 Grenoble, France
- Emergency Department and Mobile Intensive Care Unit, Grenoble University Hospital, Grenoble, France
| | - Terence Risby
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, USA
| | - Nandor Marczin
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK
- Centre of Anaesthesia and Intensive Care, Semmelweis University, Budapest, Hungary
| | - Frans J. M. Harren
- Trace Gas Research Group, Molecular and Laser Physics, IMM, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Simona M. Cristescu
- Trace Gas Research Group, Molecular and Laser Physics, IMM, Radboud University, 6525 AJ Nijmegen, The Netherlands
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Functionalizing a Tapered Microcavity as a Gas Cell for On-Chip Mid-Infrared Absorption Spectroscopy. SENSORS 2017; 17:s17092041. [PMID: 28878167 PMCID: PMC5620725 DOI: 10.3390/s17092041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/31/2017] [Accepted: 09/04/2017] [Indexed: 12/27/2022]
Abstract
Increasing demand for field instruments designed to measure gas composition has strongly promoted the development of robust, miniaturized and low-cost handheld absorption spectrometers in the mid-infrared. Efforts thus far have focused on miniaturizing individual components. However, the optical absorption path that the light beam travels through the sample defines the length of the gas cell and has so far limited miniaturization. Here, we present a functionally integrated linear variable optical filter and gas cell, where the sample to be measured is fed through the resonator cavity of the filter. By using multiple reflections from the mirrors on each side of the cavity, the optical absorption path is elongated from the physical μm-level to the effective mm-level. The device is batch-fabricated at the wafer level in a CMOS-compatible approach. The optical performance is analyzed using the Fizeau interferometer model and demonstrated with actual gas measurements.
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Ayerden NP, de Graaf G, Wolffenbuttel RF. Compact gas cell integrated with a linear variable optical filter. OPTICS EXPRESS 2016; 24:2981-3002. [PMID: 26906865 DOI: 10.1364/oe.24.002981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A miniaturized methane (CH(4)) sensor based on nondispersive infrared absorption is realized in MEMS technology. A high level of functional integration is achieved by using the resonance cavity of a linear variable optical filter (LVOF) also as a gas absorption cell. For effective detection of methane at λ = 3.39 µm, an absorption path length of at least 5 mm is required. Miniaturization therefore necessitates the use of highly reflective mirrors and operation at the 15th-order mode with a resonator cavity length of 25.4 µm. The conventional description of the LVOF in terms of the Fabry-Perot resonator is inadequate for analyzing the optical performance at such demanding boundary conditions. We demonstrate that an approach employing the Fizeau resonator is more appropriate. Furthermore, the design and fabrication in a CMOS-compatible microfabrication technology are described and operation as a methane sensor is demonstrated.
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Vainio M, Halonen L. Mid-infrared optical parametric oscillators and frequency combs for molecular spectroscopy. Phys Chem Chem Phys 2016; 18:4266-94. [DOI: 10.1039/c5cp07052j] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Review of mid-infrared optical parametric oscillators and frequency combs for high-resolution spectroscopy, including applications in trace gas detection and fundamental research.
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Affiliation(s)
- M. Vainio
- Laboratory of Physical Chemistry
- Department of Chemistry
- University of Helsinki
- Finland
- VTT Technical Research Centre of Finland Ltd
| | - L. Halonen
- Laboratory of Physical Chemistry
- Department of Chemistry
- University of Helsinki
- Finland
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Centeno R, Mandon J, Cristescu SM, Axner O, Harren FJM. External cavity diode laser-based detection of trace gases with NICE-OHMS using current modulation. OPTICS EXPRESS 2015; 23:6277-6282. [PMID: 25836848 DOI: 10.1364/oe.23.006277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We combine an external cavity diode laser with noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) using current modulation. With a finesse of 1600, we demonstrate noise equivalent absorption sensitivities of 4.1 x 10(-10) cm(-1) Hz(-1/2), resulting in sub-ppbv detection limits for Doppler-broadened transitions of CH(4) at 6132.3 cm(-1), C(2)H(2) at 6578.5 cm(-1) and HCN at 6541.7 cm(-1). The system is used for hydrogen cyanide detection from sweet almonds.
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Neerincx AH, Mandon J, van Ingen J, Arslanov DD, Mouton JW, Harren FJM, Merkus PJFM, Cristescu SM. Real-time monitoring of hydrogen cyanide (HCN) and ammonia (NH
3
) emitted by
Pseudomonas aeruginosa. J Breath Res 2015; 9:027102. [DOI: 10.1088/1752-7155/9/2/027102] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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