Quantification of methane oxidation in the rice rhizosphere using 13C-labelled methane

In this paper isotope ratio mass spectrometry is used to determine the methane (CH4) oxidation fraction in the rhizosphere of intact rice plant-soil systems. Earlier studies on quantification of the methane oxidation were based on inhibition or incubation procedures which strongly interfered with the plant-soil system and resulted in a large variability of the reported fractions, while other studies considered stable isotopes at natural abundance levels to investigate methanotrophy in the rhizosphere of rice. The current work is the first that used 13C-labelled CH4 as additive and calculated the oxidation fraction from the ratio between the added 13C-labelled CH4 and its oxidation product 13CO2. Both labelled gases could be distinguished from the natural abundance percentages. The oxidation fraction for methane was found to be smaller than 7%, suggesting that former approaches overestimate the methane oxidation fraction.

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

KAJIAN AWAL DEKTEKSI DINI PENYAKIT DALAM DENGAN METODE NON-INVASIVE SPEKTROSKOPI FOTOAKUSTIK LASER

Telah dilakukan kajian awal deteksi dini penyakit dalam menggunakan spektrometer fotoakustik (SFA) laser yang dibangun di Laboratorium Fisika Atom-Inti Jurusan Fisika FMIPA UGM. Eksperimen dilakukan dengan metode pengambilan sampel yang non-invasive yaitu melalui hembusan nafas relawan. Analisa data dari hasil eksperimen dilakukan menggunakan metode Analisis Multikoponen Gas dengan menggunakan software Origin dan Matlab. Hasil analisis dapat menunjukkan tiga macam gas karakteristik berbeda yang dapat dipakai untuk mencirikan suatu jenis penyakit tertentu, yaitu gas Etilen, Aseton dan Amonia. Kata kunci: Fotoakustik laser dan Analisis multikomponen ga

DIODE-LASER BASED PHOTO-ACOUSTIC SPECTROSCOPY IN ATMOSPHERIC NO­2 DETECTION

We have developed a simple, low cost, and compact NO2 detection system. It’s based on photoacoustic spectroscopy (PAS) method uses a diode laser as a source of radiation. The PAS system has a detection limit of 10 ppbv for NO2. With this set-up we were able to detect the NO2 concentration from urban air near our campus. We have also investigated the NO2 dissociation effect on the PAS system via NO measurements using a direct absorption spectroscopy method on quantum cascade laser (QCL) system. Keywords: photoacoustic spectroscop

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

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

Small-Size Resonant Photoacoustic Cell of Inclined Geometry for Gas Detection

A photoacoustic cell intended for laser detection of trace gases is represented. The cell is adapted so as to enhance the gas-detection performance and, simultaneously, to reduce the cell size. The cell design provides an efficient cancellation of the window background (a parasite response due to absorption of laser beam in the cell windows) and acoustic isolation from the environment for an acoustic resonance of the cell. The useful photoacoustic response from a detected gas, window background and noise are analyzed in demonstration experiments as functions of the modulation frequency for a prototype cell with the internal volume ~ 0.5 cm^3. The minimal detectable absorption for the prototype is estimated to be ~ 1.2 10^{-8} cm^{-1} W Hz^{-1/2}.Comment: 11 pages, 5 figure

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

Beyond hypoxia : rice seedlings between lipid peroxidation and fermentation

Contains fulltext : 93582.pdf (author's version ) (Open Access)28 p

Photonics-based gas sensing for agricultural and medical applications

Item does not contain fulltextOSA Energy and Environment conference 201