Towards screening Barrett’s Oesophagus: current guidelines, imaging modalities and future developments

Barrett’s oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett’s oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett’s oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett’s oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett’s oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett’s oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials

The performance and the characterization of laser ablation aerosol particle time-of-flight mass spectrometry (LAAP-ToF-MS)

SSCI-VIDE+CARE+NHYInternational audienceHyphenated laser ablation-mass spectrometry instruments have been recognized as useful analytical tools for the detection and chemical characterization of aerosol particles. Here we describe the performances of a laser ablation aerosol particle time-of-flight mass spectrometer (LAAP-ToF-MS) which was designed for aerodynamic particle sizing using two 405 nm scattering lasers and characterization of the chemical composition of single aerosol particle via ablation/ionization by a 193 nm excimer laser and detection in a bipolar time-of-flight mass spectrometer with a mass resolving power of m/Delta m > 600. We describe a laboratory based optimization strategy for the development of an analytical methodology for characterization of atmospheric particles using the LAAP-ToF-MS instrument in combination with a particle generator, a differential mobility analyzer and an optical particle counter. We investigated the influence of particle number concentration, particle size and particle composition on the detection efficiency. The detection efficiency is a product of the scattering efficiency of the laser diodes and the ionization efficiency or hit rate of the excimer laser. The scattering efficiency was found to vary between 0.6 and 1.9% with an average of 1.1 %; the relative standard deviation (RSD) was 17.0 %. The hit rate exhibited good repeatability with an average value of 63% and an RSD of 18 %. In addition to laboratory tests, the LAAP-ToF-MS was used to sample ambient air during a period of 6 days at the campus of Aix-Marseille University, situated in the city center of Marseille, France. The optimized LAAP-ToF-MS methodology enables high temporal resolution measurements of the chemical composition of ambient particles, provides new insights into environmental science, and a new investigative tool for atmospheric chemistry and physics, aerosol science and health impact studies

Abiotic Interfacial Photochemistry of Biogenic Surfactants as a Major Source of Volatile Organic Compounds

SSCI-VIDE+CARE+NHY:ABO:SPR:CGOInternational audienceSurfaces coated with biogenic surfactants exposed to the atmosphere are ubiquitous and are commonly present on aerosol particles, cloud droplets, buildings, plants, and oceans. As shown in the past, photochemical reactions taking places at these air/water interfaces lead to unique chemical pathways, producing volatile organic compounds (VOCs) and leading to secondary organic aerosol formation.Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions [1]. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants, and VOC production. In agreement with our previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy-radical chemistry. Up to now, such VOC emissions were directly attributed to high biological activity in surface water. However, our results suggest that abiotic photochemistry can lead to similar atmospheric emissions, especially in low biologically-active regions. Furthermore, chamber experiments suggested that oxidation (O3/OH-radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth's radiation budget.[1] M. Brüggemann and N. Hayeck et al., Faraday Discussions, 2017, DOI: 10.1039/c7fd00022

Abiotic interfacial photochemistry of biogenic surfactants as a major source of volatile organic compounds

SSCI-VIDE+CARE+NHY:MBM:SPR:CGOInternational audienceSurfaces coated with biogenic surfactants exposed to the atmosphere are ubiquitous and are commonly present on aerosol particles, cloud droplets, buildings, plants, and oceans. As shown in the past, photochemical reactions taking places at these air/water interfaces lead to unique chemical pathways, producing volatile organic compounds (VOCs) and leading to secondary organic aerosol formation. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions [1]. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants, and VOC production. In agreement with our previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy-radical chemistry. Up to now, such VOC emissions were directly attributed to high biological activity in surface water. However, our results suggest that abiotic photochemistry can lead to similar atmospheric emissions, especially in low biologically-active regions. Furthermore, chamber experiments suggested that oxidation (O3 /OH-radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth’s radiation budget.[1] M. Brüggemann et al., Faraday Discussions, 2017, in press

Abiotic interfacial photochemistry of biogenic surfactants as a major source of volatile organic compounds

SSCI-VIDE+CARE+NHY:MBM:SPR:CGOInternational audienceSurfaces coated with biogenic surfactants exposed to the atmosphere are ubiquitous and are commonly present on aerosol particles, cloud droplets, buildings, plants, and oceans. As shown in the past, photochemical reactions taking places at these air/water interfaces lead to unique chemical pathways, producing volatile organic compounds (VOCs) and leading to secondary organic aerosol formation. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions [1]. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants, and VOC production. In agreement with our previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy-radical chemistry. Up to now, such VOC emissions were directly attributed to high biological activity in surface water. However, our results suggest that abiotic photochemistry can lead to similar atmospheric emissions, especially in low biologically-active regions. Furthermore, chamber experiments suggested that oxidation (O3 /OH-radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth’s radiation budget.[1] M. Brüggemann et al., Faraday Discussions, 2017, in press