On-Line Monitoring of Radiocarbon Emissions in a Nuclear Facility with Cavity Ring-Down Spectroscopy.
Ontology highlight
ABSTRACT:
SUBMITTER: Lehmuskoski J
PROVIDER: S-EPMC8655739 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A cavity ring-down spectroscopy (CRDS) instrument was developed using mature, robust hardware for the measurement of carbon-14 in biological studies. The system was characterized using carbon-14 elevated glucose samples and returned a linear response up to 387 times contemporary carbon-14 concentrations. Carbon-14 free and contemporary carbon-14 samples with varying carbon-13 concentrations were used to assess the method detection limit of approximately one-third contemporary carbon-14 levels. Sources of inaccuracies are presented and discussed, and the capability to measure carbon-14 in biological samples is demonstrated by comparing pharmacokinetics from carbon-14 dosed guinea pigs analyzed by both CRDS and accelerator mass spectrometry. The CRDS approach presented affords easy access to powerful carbon-14 tracer techniques that can characterize complex biochemical systems.
| S-EPMC5257295 | biostudies-literature
Project description:S-Nitroso compounds have received much attention in biological research. In addition to their role as nitric oxide donors, there is growing evidence that these compounds are involved in signaling processes in biological systems. Determination of S-nitrosylated proteins is of great importance for fundamental biological research and medical applications. The most common method to assay biological S-nitroso compounds is to chemically or photochemically reduce SNO functional groups to release nitric oxide, which is then entrained in an inert gas stream and detected, usually through chemiluminescence. We report a method of S-nitroso compound detection using cavity ring-down measurements of gaseous NO absorbance at 5.2 ?m. The proposed method, in contrast to the chemiluminescence-based approach, can be used to distinguish isotopic forms of NO. We demonstrated sensitivity down to ?2 pmol of S(14)NO groups and ?5 pmol of S(15)NO groups for S-nitroso compounds in aqueous solutions. The wide dynamic range of cavity ring-down detection allows the measurement of S-nitroso compound levels from pico- to nanomole amounts.
| S-EPMC4519009 | biostudies-literature
Project description:Hydrogen cyanide (HCN) has been recognized as a potential biomarker for non-invasive diagnosis of Pseudomonas aeruginosa infection in the lung. However, the oral cavity is a dominant production site for exhaled HCN and this contribution can mask the HCN generated in the lung. It is thus important to understand the sources of HCN production in the oral cavity. By screening of oral anaerobes for HCN production, we observed that the genus of Porphyromonas, Prevotella and Fusobacterium generated low levels of HCN in vitro. This is the first study to show that oral anaerobes are capable of producing HCN in vitro. Further investigations were conducted on the species of P. gingivalis and we successfully detected HCN production (0.9-10.9 ppb) in the headspace of three P. gingivalis reference strains (ATCC 33277, W50 and OMG 434) and one clinical isolate. From P. gingivalis ATCC 33277 and W50, a strong correlation between HCN and CO2 concentrations (rs = 0.89, p < 0.001) was observed, indicating that the HCN production of P. gingivalis might be connected with the bacterial metabolic activity. These results indicate that our setup could be widely applied to the screening of in vitro HCN production by both aerobic and anaerobic bacteria.
| S-EPMC4778072 | biostudies-other
Project description:New therapeutic biological entities such as bispecific antibodies targeting tissue or specific cell populations form an increasingly important part of the drug development portfolio. However, these biopharmaceutical agents bear the risk of extensive target-mediated drug disposition or atypical pharmacokinetic properties as compared to canonical antibodies. Pharmacokinetics and bio-distribution studies become therefore more and more important during lead optimization. Biologics present, however, greater analytical challenges than small molecule drugs due to the mass and selectivity limitation of mass spectrometry and ligand-binding assay, respectively. Radiocarbon (14C) and its detection methods, such as the emerging 14C cavity ring down spectroscopy (CRDS), thus can play an important role in the large molecule quantitation where a 14C-tag is covalently bound through a stable linker. CRDS has the advantage of a simplified sample preparation and introduction system as compared to accelerator mass spectrometry (AMS) and can be accommodated within an ordinary research laboratory. In this study, we report on the labeling of an anti-IL17 IgG1 model antibody with 14C propionate tag and its detection by CRDS using it as nanotracer (2.1 nCi or 77.7 Bq blended with the therapeutic dose) in a pharmacokinetics study in a preclinical species. We compare these data to data generated by AMS in parallel processed samples. The derived concentration time profiles for anti-IL17 by CRDS were in concordance with the ones derived by AMS and ?-counting of an 125I-labeled anti-IL17 radiotracer and were well described by a 2-compartment population pharmacokinetic model. In addition, antibody tissue distribution coefficients for anti-IL17 were determined by CRDS, which proved to be a direct and sensitive measurement of the extravascular tissue concentration of the antibody when tissue perfusion was applied. Thus, this proof-of-concept study demonstrates that trace 14C-radiolabels and CRDS are an ultrasensitive approach in (pre)clinical pharmacokinetics and bio-distribution studies of new therapeutic entities.
| S-EPMC6192596 | biostudies-literature
Project description:We present the development, integration, and testing of an open-path cavity ring-down spectroscopy (CRDS) methane sensor for deployment on small unmanned aerial systems (sUAS). The open-path configuration used here (without pump or flow-cell) enables a low mass (4 kg) and low power (12 W) instrument that can be readily integrated to sUAS, defined here as having all-up mass of <25 kg. The instrument uses a compact telecom style laser at 1651 nm (near-infrared) and a linear 2-mirror high-finesse cavity. We show test results of flying the sensor on a DJI Matrice 600 hexacopter sUAS. The high sensitivity of the CRDS method allows sensitive methane detection with a precision of ~10-30 ppb demonstrated for actual flight conditions. A controlled release setup, where known mass flows are delivered, was used to simulate point-source methane emissions. Examples of methane plume detection from flight tests suggest that isolated plumes from sources with a mass flow as low as ~0.005 g/s can be detected. The sUAS sensor should have utility for emissions monitoring and quantification from natural gas infrastructure. To the best of our knowledge, it is also the first CRDS sensor directly deployed onboard an sUAS.
| S-EPMC7014388 | biostudies-literature
Project description:Spectroscopy of whispering-gallery mode microresonators has become a powerful scientific tool, enabling the detection of single viruses, nanoparticles and even single molecules. Yet the demonstrated timescale of these schemes has been limited so far to milliseconds or more. Here we introduce a scheme that is orders of magnitude faster, capable of capturing complete spectral snapshots at nanosecond timescales-cavity ring-up spectroscopy. Based on sharply rising detuned probe pulses, cavity ring-up spectroscopy combines the sensitivity of heterodyne measurements with the highest-possible, transform-limited acquisition rate. As a demonstration, we capture spectra of microtoroid resonators at time intervals as short as 16 ns, directly monitoring submicrosecond dynamics of their optomechanical vibrations, thermorefractive response and Kerr nonlinearity. Cavity ring-up spectroscopy holds promise for the study of fast biological processes such as enzyme kinetics, protein folding and light harvesting, with applications in other fields such as cavity quantum electrodynamics and pulsed optomechanics.
| S-EPMC4410630 | biostudies-other
Project description:Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.
| S-EPMC4534253 | biostudies-other
Project description:The recent development of cavity ring-down laser spectroscopy (CRDS) instruments capable of measuring (17) O-excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen ((17) O/(16) O, (18) O/(16) O) and hydrogen ((2) H/(1) H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post-depositional interaction with other fluids.We developed a semi-automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (?(17) O, ?(18) O and ?(2) H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long-term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of (17) O-excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2 .The long-term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for ?(17) O values, ±0.13‰ for ?(18) O values and ±0.49‰ for ?(2) H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium-excess and (17) O-excess, respectively. Accurate measurement of the (17) O-excess values of GHW, of both synthetic and natural samples, requires the use of a micro-combustion module (MCM). This accessory removes contaminants (VOCs, H2 S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods.We demonstrate that precise and simultaneous isotopic measurements of ?(17) O, ?(18) O and ?(2) H values, and the derived deuterium-excess and (17) O-excess, can be obtained from GHW and brines using a new extraction apparatus and subsequent measurement by CRDS. This method provides new opportunities for the application of water isotope tracers in hydrologic and paleoclimatologic research.
| S-EPMC5132057 | biostudies-other
Project description:Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5-38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg-1 C in 2010 to 226.0 Bq kg-1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012-2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4 Bq kg-1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30 km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources.
| S-EPMC5107918 | biostudies-literature
Project description:The strong coupling of atoms and molecules to radiation field modes in optical cavities creates dressed matter/field states known as polaritons with controllable dynamical and energy transfer properties. We propose a multidimensional optical spectroscopy technique for monitoring polariton dynamics. The response of a two-level atom to the time-dependent coupling to a single-cavity mode is monitored through time-and-frequency-resolved single-photon coincidence measurements of spontaneous emission. Polariton population and coherence dynamics and its variation with cavity photon number and controlled by gating parameters are predicted by solving the Jaynes-Cummings model.
| S-EPMC5816200 | biostudies-literature