Mid-infrared dual-comb spectroscopy for real-time gas analysis with an optical parametric oscillator

Item does not contain fulltext2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec

A breach in plant defences: Pseudomonas syringae pv. actinidiae targets ethylene signalling to overcome Actinidia chinensis pathogen responses

8openInternationalBothEthylene interacts with other plant hormones to modulate many aspects of plant metabolism, including defence and stomata regulation. Therefore, its manipulation may allow plant pathogens to overcome the host’s immune responses. This work investigates the role of ethylene as a virulence factor for Pseudomonas syringae pv. actinidiae (Psa), the aetiological agent of the bacterial canker of kiwifruit. The pandemic, highly virulent biovar of this pathogen produces ethylene, whereas the biovars isolated in Japan and Korea do not. Ethylene production is modulated in planta by light/dark cycle. Exogenous ethylene application stimulates bacterial virulence, and restricts or increases host colonisation if performed before or after inoculation, respectively. The deletion of a gene, unrelated to known bacterial biosynthetic pathways and putatively encoding for an oxidoreductase, abolishes ethylene production and reduces the pathogen growth rate in planta. Ethylene production by Psa may be a recently and independently evolved virulence trait in the arms race against the host. Plant- and pathogen-derived ethylene may concur in the activation/suppression of immune responses, in the chemotaxis toward a suitable entry point, or in the endophytic colonisationopenCellini, Antonio; Donati, Irene; Farneti, Brian; Khomenko, Iuliia; Buriani, Giampaolo; Biasioli, Franco; Cristescu, Simona M.; Spinelli, Francesco;Cellini, A.; Donati, I.; Farneti, B.; Khomenko, I.; Buriani, G.; Biasioli, F.; Cristescu, S.M.; Spinelli, F

Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing

A continuous wave optical parametric oscillator, generating up to 300 mW idler output in the 3–4 μm wavelength region, and pumped by a fiber-amplified DBR diode laser is used for trace gas detection by means of quartz-enhanced photoacoustic spectroscopy (QEPAS). Mode-hop-free tuning of the OPO output over 5.2 cm-1 and continuous spectral coverage exceeding 16.5 cm-1 were achieved via electronic pump source tuning alone. Online monitoring of the idler wavelength, with feedback to the DBR diode laser, provided an automated closed-loop control allowing arbitrary idler wavelength selection within the pump tuning range and locking of the idler wavelength with a stability of 1.7×10-3 cm-1 over at least 30 min.\ud \ud Using this approach, we locked the idler wavelength at an ethane absorption peak and obtained QEPAS data to verify the linear response of the QEPAS signal at different ethane concentrations (100 ppbv-20 ppmv) and different power levels. The detection limit for ethane was determined to be 13 ppbv (20 s averaging), corresponding to a normalized noise equivalent absorption coefficient of 4.4×10-7 cm-1  W/Hz1/2

Non-Invasive Monitoring of Inflammation in Inflammatory Bowel Disease Patients during Prolonged Exercise via Exhaled Breath Volatile Organic Compounds

The aim of this study was to investigate volatile organic compounds (VOCs) in exhaled breath as possible non-invasive markers to monitor the inflammatory response in inflammatory bowel disease (IBD) patients as a result of repeated and prolonged moderate-intensity exercise. We included 18 IBD patients and 19 non-IBD individuals who each completed a 30, 40, or 50 km walking exercise over three consecutive days. Breath and blood samples were taken before the start of the exercise event and every day post-exercise to assess changes in the VOC profiles and cytokine concentrations. Proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) was used to measure exhaled breath VOCs. Multivariate analysis, particularly ANOVA-simultaneous component analysis (ASCA), was employed to extract relevant ions related to exercise and IBD. Prolonged exercise induces a similar response in breath butanoic acid and plasma cytokines for participants with or without IBD. Butanoic acid showed a significant correlation with the cytokine IL-6, indicating that butanoic acid could be a potential non-invasive marker for exercise-induced inflammation. The findings are relevant in monitoring personalized IBD management

Exhaled breath reflects prolonged exercise and statin use during a field campaign

Volatile organic compounds (VOCs) in exhaled breath provide insights into various metabolic processes and can be used to monitor physiological response to exercise and medication. We integrated and validated in situ a sampling and analysis protocol using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) for exhaled breath research. The approach was demonstrated on a participant cohort comprising users of the cholesterol-lowering drug statins and non-statin users during a field campaign of three days of prolonged and repeated exercise, with no restrictions on food or drink consumption. The effect of prolonged exercise was reflected in the exhaled breath of participants, and relevant VOCs were identified. Most of the VOCs, such as acetone, showed an increase in concentration after the first day of walking and subsequent decrease towards baseline levels prior to walking on the second day. A cluster of short-chain fatty acids including acetic acid, butanoic acid, and propionic acid were identified in exhaled breath as potential indicators of gut microbiota activity relating to exercise and drug use. We have provided novel information regarding the use of breathomics for non-invasive monitoring of changes in human metabolism and especially for the gut microbiome activity in relation to exercise and the use of medication, such as statin

The suitability of Tedlar bags for breath sampling in medical diagnostic research

Contains fulltext : 36615pub.pdf (publisher's version ) (Open Access)Tedlar bags are tested for their suitability for breath sampling for medical diagnostic purposes. Proton-transfer reaction-mass spectrometry was used to monitor the changes in composition of various mixtures contained in custom-made black-layered Tedlar bags. Characteristic ions at m/z 88 and 95 amu reflect considerable pollution from the bag material. The pollutant found on m/z 88 amu is most probably N,N-dimethylacetamide, a latent solvent used in the production of Tedlar film. Gas composition losses during filling were found to range from 5 to 47%, depending on the compound. Once stored, the half-lives of methanol, acetaldehyde, acetone, isoprene, benzene, toluene and styrene were estimated between 5 and 13 days. Losses from breath samples (52 h after filling) were found to be less than 10%. No observable decrease was found for ethylene over 3 days, using laser-based photoacoustic detection. For the use of Tedlar bags, a standardized protocol is advised, where the time point of analysis is fixed for all samples and should be kept as close as possible to the time of sampling

Real-time, subsecond, multicomponent breath analysis by optical parametric oscillator based off-axis integrated cavity output spectroscopy

Contains fulltext : 92259.pdf (publisher's version ) (Open Access)12 p

Sensitivity enhancement in off-axis integrated cavity output spectroscopy

Contains fulltext : 135563.pdf (publisher's version ) (Open Access

Femtosecond optical parametric oscillators toward real-time dual-comb spectroscopy

Contains fulltext : 144943.pdf (publisher's version ) (Open Access