ACTRIS ACSM intercomparison – Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers

Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs) performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM) from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM), and one high-resolution ToF aerosol mass spectrometer (AMS) were operated in parallel for about 3 weeks in November and December~2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF) utilising the multilinear engine 2 (ME-2). Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44), which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA), cooking-related organic aerosol (COA), biomass burning-related organic aerosol (BBOA) and secondary oxygenated organic aerosol (OOA). ME-2 boundary conditions (profile constraints) were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles). A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD) from the mean between 13.7 and 22.7 % of the source's average mass contribution depending on the factors (HOA: 14.3 ± 2.2 %, COA: 15.0 ± 3.4 %, OOA: 41.5 ± 5.7 %, BBOA: 29.3 ± 5.0 %). Factors which tend to be subject to minor factor mixing (in this case COA) have higher relative uncertainties than factors which are recognised more readily like the OOA. Averaged over all factors and instruments the relative first SD from the mean of a source extracted with ME-2 was 17.2 %.JRC.H.2-Air and Climat

The second ACTRIS inter-comparison (2016) for Aerosol Chemical Speciation Monitors (ACSM) : Calibration protocols and instrument performance evaluations

AbstractThis work describes results obtained from the 2016 Aerosol Chemical Speciation Monitor (ACSM) intercomparison exercise performed at the Aerosol Chemical Monitor Calibration Center (ACMCC, France). Fifteen quadrupole ACSMs (Q_ACSM) from the European Research Infrastructure for the observation of Aerosols, Clouds and Trace gases (ACTRIS) network were calibrated using a new procedure that acquires calibration data under the same operating conditions as those used during sampling and hence gets information representative of instrument performance. The new calibration procedure notably resulted in a decrease in the spread of the measured sulfate mass concentrations, improving the reproducibility of inorganic species measurements between ACSMs as well as the consistency with co-located independent instruments. Tested calibration procedures also allowed for the investigation of artifacts in individual instruments, such as the overestimation of m/z 44 from organic aerosol. This effect was quantified by the m/z (mass-to-charge) 44 to nitrate ratio measured during ammonium nitrate calibrations, with values ranging from 0.03 to 0.26, showing that it can be significant for some instruments. The fragmentation table correction previously proposed to account for this artifact was applied to the measurements acquired during this study. For some instruments (those with high artifacts), this fragmentation table adjustment led to an ?overcorrection? of the f44 (m/z 44/Org) signal. This correction based on measurements made with pure NH4NO3, assumes that the magnitude of the artifact is independent of chemical composition. Using data acquired at different NH4NO3 mixing ratios (from solutions of NH4NO3 and (NH4)2SO4) we observe that the magnitude of the artifact varies as a function of composition. Here we applied an updated correction, dependent on the ambient NO3 mass fraction, which resulted in an improved agreement in organic signal among instruments. This work illustrates the benefits of integrating new calibration procedures and artifact corrections, but also highlights the benefits of these intercomparison exercises to continue to improve our knowledge of how these instruments operate, and assist us in interpreting atmospheric chemistry.Peer reviewe

ACTRIS ACSM intercomparison – Part 1: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with co-located instruments

As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for 3 weeks during the late-fall – early-winter period (November–December 2013). The first week was dedicated to the tuning and calibration of each instrument, whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical, and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium, and chloride) in the non-refractory submicron aerosols (NR-PM1) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r2 > 0.9) were observed systematically for each individual Q-ACSM across all chemical families except for chloride for which three Q-ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025, 1999) and were found to be 9, 15, 19, 28, and 36 % for NR-PM1, nitrate, organic matter, sulfate, and ammonium, respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of Q-ACSMs, detailed intercomparison results are presented, along with a discussion of some recommendations about best calibration practices, standardized data processing, and data treatment.JRC.H.2-Air and Climat

Impact of the microenvironment and tumor vasculature in the response of osteosarcoma to chemotherapy

L'ostéosarcome, la tumeur osseuse primitive maligne la plus fréquente, est actuellement traité par chimiothérapie et chirurgie. Des travaux récents suggèrent que le microenvironnement tumoral pourrait être un élément clé dans la compréhension de la tumorigénèse et du traitement de l’ostéosarcome. Nous avons émis l'hypothèse que l'hétérogénéité du microenvironnement pourrait moduler la réponse à la chimiothérapie. Nous avons également évalué des marquages spécifiques de vascularisation en immunohistochimie liés à la zone et à la qualité de réponse au traitement. L’initiation tumorale de modèle MOS-J syngenique d’ostéosarcome murin a été réalisé dans les sites intra-osseux et paratibial. Nous observions une différence significative dans la réponse au traitement par doxorubicine entre ces deux conditions en termes de volume tumoral et de nécrose induite. Nous avons ensuite analysé le réseau vasculaire sur différentes régions par immunohistochimie en immunofluorescence par multiplexing. La doxorubicine semble réduire l'expression des éléments CD31+ dans le front d'invasion. Nous observions une distribution spécifique des deux types de vaisseaux évalués en microscopie confocale : les vaisseaux serpigineux, immatures CD31+/endomucine+ et les vaisseaux matures CD31+/α-SMA+. Ces derniers pourraient être liés à une bonne réponse au traitement dans notre modèle murin car ils étaient quatre fois plus présents dans notre modèle intra-osseux de bonne réponse à la doxorubicine. Ces travaux suggèrent un rôle décisif du microenvironnement dans la réponse de l'ostéosarcome à la chimiothérapie avec une cinétique de volume tumoral et une nécrose variable entre les deux sites de développement de notre modèle. L'analyse vasculaire innovante en immunofluorescence par multiplexing doit être évaluée de manière dynamique, avec une analyse précoce du développement tumoral, pour comprendre si les vaisseaux matures CD31+/α-SMA+ sont les marqueurs d’un facteur de bon pronostic ou ceux d’une normalisation vasculaire. Des tumeurs osseuses humaines devraient être évaluées sur ces marqueurs vasculaires spécifiques en tant que potentiels marqueurs de bonne réponse à la chimiothérapie.Osteosarcoma, the most common malignant primary bone tumor, is currently treated with chemotherapy and surgery. Recent works suggest that the tumor microenvironment may be a key element in tumor development and therapeutic understandings. We hypothesized that microenvironment heterogeneity may play a role in its response to chemotherapy. We also search for specific vascularization labelings in immunohistochemistry linked to the area and the quality of response to treatment. Tumor initiation site with osteosarcoma MOS-J syngeneic mouse model was performed in intra-osseous and paratibial sites. We observe a significant difference in the Doxorubicin treatment response between these two conditions in tumor volume and induced necrosis. We then focused our vascular network analysis on different areas with immunohistochemistry and immunofluorescent multiplexing in control and Doxorubicin conditions. Doxorubicin seems to lower CD31+ element expression in the invasion front. We observe a specific distribution of the two kinds of vessels assessed in confocal microscopy CD31+/endomucin+ sprouting vessels and CD31+/α-SMA+ mature vessels. These last ones may be linked to a good response to chemotherapy in our mouse model as they were four times more present in our intra-osseous good response model to chemotherapy. This work suggests a decisive microenvironment role in osteosarcoma response to chemotherapy with differential tumor kinetic and necrosis between two development sites in our model. The innovative vascular analysis by immunohistochemistry multiplexing must be assessed dynamically, with an earlier tumor development analysis, to understand if the CD31+/α-SMA+mature vessels are a good prognosis marker or a vascular normalization. Human tumor bone material should be evaluated on these specific vascular markers as potential useful response markers to chemotherapy

Mesures en temps réel de la fraction fine des aérosols et spéciation de composés organiques présents dans les PM2,5 d'une zone urbaine sous influence industrielle

National audienc

Caractérisation de particules fines prélevées sur un site de fond urbain

National audienc

Sensory Neurotization of the Ulnar Nerve, Surgical Techniques and Functional Outcomes: A Review

When ulnar nerve lesions happen above the wrist level, sensation recovery after acute repair or nerve grafting is often challenging. Distal sensory nerve transfers may be an option for overcoming these sequelae. However, little data has been published on this topic. This study aims to review the surgical procedures currently proposed, along with their functional results. Six donor nerves have been described at the wrist level: the palmar branch of the median nerve, the cutaneous branch of the median nerve to the palm with or without fascicles of the ulnar digital nerve of the index finger, the posterior interosseous nerve, the third palmar digital nerve, the radial branch of the superficial radial nerve, the median nerve, and the fascicule for the third web space. Three donor nerves have been reported at the hand level: the ulnar digital nerves of the index, and the radial or ulnar digital nerves of the long finger. Three target sites were used: the superficial branch of the ulnar nerve, the dorsal branch of the ulnar nerve, and the ulnar digital branch of the fifth digit. All the technical points have been illustrated with anatomical dissection pictures. After assessing sensory recovery using the British Medical Research Council scale, a majority of excellent recoveries scaled S3+ or S4 have been reported in the targeted territory for each technique

Sensory Neurotization of the Ulnar Nerve, Surgical Techniques and Functional Outcomes: A Review

When ulnar nerve lesions happen above the wrist level, sensation recovery after acute repair or nerve grafting is often challenging. Distal sensory nerve transfers may be an option for overcoming these sequelae. However, little data has been published on this topic. This study aims to review the surgical procedures currently proposed, along with their functional results. Six donor nerves have been described at the wrist level: the palmar branch of the median nerve, the cutaneous branch of the median nerve to the palm with or without fascicles of the ulnar digital nerve of the index finger, the posterior interosseous nerve, the third palmar digital nerve, the radial branch of the superficial radial nerve, the median nerve, and the fascicule for the third web space. Three donor nerves have been reported at the hand level: the ulnar digital nerves of the index, and the radial or ulnar digital nerves of the long finger. Three target sites were used: the superficial branch of the ulnar nerve, the dorsal branch of the ulnar nerve, and the ulnar digital branch of the fifth digit. All the technical points have been illustrated with anatomical dissection pictures. After assessing sensory recovery using the British Medical Research Council scale, a majority of excellent recoveries scaled S3+ or S4 have been reported in the targeted territory for each technique

Seasonal variations and characterization of PM2.5 sampled at an industrialized coastal site in Northern France

International audienc

Comparison of fine aerosols chemical composition sampled at an urban background site and an industrialized coastal site

International audienc