Generation of CO2 gas mixtures by dynamic dilution for the development of gaseous certified reference materials

The use of Certified Reference Materials (CRMs) is of utmost importance to achieve the comparability and traceability of data, which are essential features of measurement results in environmental and climate fields. The present paper focuses on the generation of gas mixtures at known composition of carbon dioxide at atmospheric amount-of-substance fraction in synthetic air by means of a dynamic dilution system, designed and implemented at the Istituto Nazionale di Ricerca Metrologica (INRiM). The validation of the dynamic system in terms of amount-of-substance fraction is presented. The system was also used to verify the carbon dioxide amount-ofsubstance fraction of a suite of gas mixtures gravimetrically prepared at INRiM in the framework of the EMPIR Joint Research Project 19ENV05 – STELLAR. Dynamic dilution proved to be an effective tool for the preparation and certification of CRMs for gaseous pollutants (i.e. carbon dioxide, nitrogen oxides) relevant for monitoring environmental pollution and climate changes

Au-Coated Ni80Fe20 Submicron Magnetic Nanodisks: Interactions With Tumor Cells

Effective interaction and accumulation of nanoparticles (NPs) within tumor cells is crucial for NP-assisted diagnostic and therapeutic biomedical applications. In this context, the shape and size features of NPs can severely influence the strength of adhesion between NPs and cell and the NP internalization mechanisms. This study proved the ability of the PT45 and A549 tumor cells to uptake and retain magnetic Au-coated Ni80Fe20 nanodisks (NDs) prepared by means of a bottom–up self-assembling nanolithography technique assisted by polystyrene nanospheres. The chosen geometrical parameters, i.e., diameter (≈650 nm) and thickness (≈30 nm), give rise to magnetic domain patterns arranged in vortex state at the magnetic remanence. PT45 and A549 cell lines were cultured in the presence of different concentrations of Au-coated Ni80Fe20 nanodisks, and their biocompatibility was evaluated by viability and proliferation tests. Electron microscopy techniques and a combined CARS (Coherent Anti-stokes Raman Scattering) and TPL (two-photon photoluminescence) microscopy allow localizing and distinguishing the NDs within or attached to the tumor cells, without any labeling. A quantitative measurement of ND amount retained within tumor cells as a function of ND concentrations was performed by the Instrumental Neutron Activation Analysis (INAA) characterization technique

Realisation of gas reference materials of CO2 in air at known isotopic composition

The accurate and reliable determination of carbon dioxide (CO2) levels in atmosphere, together with its isotopic composition, is fundamental to monitor the trends of this gas in atmosphere and to support the prediction of its future increase on a global scale. The determination of the isotopic composition of CO2 can support the assessment of the uptake of CO2 in the environmental compartments, and can help to distinguish natural from anthropogenic carbon in the atmosphere. In this regard, INRIM started an activity for the development of new reference gas mixtures of CO2 at ambient amount fraction in high pressure cylinders with different isotopic compositions, to cover the range -48 ‰ to -8 ‰ vs VPDB for δ13C and -27 ‰ to +2 ‰ vs VPDB for δ18O, with uncertainty targets of 0.1 ‰ for δ13C-CO2 and 0.5 ‰ for δ18O-CO2. The activity was carried out in the framework of the EMPIR project 16ENV06 “Metrology for stable isotope reference standards - SIRS”, and it is now continuing with the project 19ENV05 “Stable isotope metrology to enable climate action and regulation – STELLAR”. Selected commercial pure CO2 were used to prepare different CO2 reference materials in high pressure cylinders by using the gravimetric method, adapting the INRIM procedure applied to the preparation of CO2 in N2/synthetic air mixtures. Starting from these pure materials, CO2 mixtures in synthetic air at atmospheric amount fraction were prepared. The prepared mixtures were then sent to the Max Planck Institute for Biogeochemistry (MPI-BGC), for the validation of their isotopic values. A sampling system was set up for the preparation of the CO2 samples sent for validation, in order to minimise fractionation effects during the sampling. An appropriate uncertainty budget was developed for the reference mixtures, by taking into account all the relevant uncertainty contributions

Comparison of gravimetry and dynamic dilution for the generation of reference gas mixtures of CO2 at atmospheric amount fraction

Carbon dioxide (CO2) is the most important greenhouse gas generated by human activities. Its concentration has been growing in the atmosphere reaching a current annual average of 410 μmol mol−1. Reliable determinations of the atmospheric CO2 concentration are of great importance for the development of models used in climate change predictions. The production of reference mixtures of known composition is a key step for the achievement of reliable data for the monitoring of greenhouse gases in atmosphere.The present work deals with a comparison of two methods for gas mixtures preparation, the first based on the gravimetric preparation of gas mixtures in high pressure cylinders and the second based on dynamic dilution, for generating gas mixtures at the desired amount fraction online.Reference mixtures of CO2 can be used for the calibration of monitoring sensors, with various applications ranging from environmental monitoring to industrial process control

Reference materials: gas mixtures to support measurements for climate change studies

This work aims at presenting some activities carried out at INRiM for the development of new reference materials (RMs) of greenhouse gases to support measurements for climate change studies. Since the preindustrial era, greenhouse gases emissions due to human activities have dramatically increased, mostly due to economic and demographic growth and their concentrations in the atmosphere have grown continuously since 2011, reaching highest levels in 2019. The increase of greenhouse gases concentration in atmosphere due to anthropogenic emissions is the main cause of global warming and carbon dioxide (CO2) is one of the main culprits for this phenomenon. In this context, the capability of discriminating between anthropogenic and natural emissions is of utmost importance. The determination of the isotopic composition of CO2 can support the assessment of the uptake of CO2 in the environmental compartments, i.e. atmosphere and hydrosphere, and can help to distinguish natural from anthropogenic carbon in the atmosphere. The possibility to establish metrological traceability of the measurements of CO2 isotopic composition is a key aspect, and greatly relies on the availability of gaseous reference materials having compositions and uncertainties that are fit for purpose. In the past years, INRiM participated in the EMPIR project 16ENV06 SIRS “Metrology for stable isotope reference standards”, and is now taking part in the EMPIR project 19ENV05 STELLAR “Stable isotope metrology to enable climate action and regulation”. INRiM has experience in the preparation of gas standards by primary methods, namely gravimetry and dynamic dilution, which can be applied to the realisation of reference materials of CO2 at known isotopic composition. The present work describes the preliminary results obtained by INRiM in the preparation of pure CO2 RMs and at atmospheric amount fraction. Examples of uncertainty budgets and identification of the uncertainty sources are also given

Reference materials: gas mixtures to support measurements for climate change studies

This work aims at presenting some activities carried out at INRiM for the development of new reference materials (RMs) of greenhouse gases to support measurements for climate change studies. Since the preindustrial era, greenhouse gases emissions due to human activities have dramatically increased, mostly due to economic and demographic growth and their concentrations in the atmosphere have grown continuously since 2011, reaching highest levels in 2019. The increase of greenhouse gases concentration in atmosphere due to anthropogenic emissions is the main cause of global warming and carbon dioxide (CO2) is one of the main culprits for this phenomenon. In this context, the capability of discriminating between anthropogenic and natural emissions is of utmost importance. The determination of the isotopic composition of CO2 can support the assessment of the uptake of CO2 in the environmental compartments, i.e. atmosphere and hydrosphere, and can help to distinguish natural from anthropogenic carbon in the atmosphere. The possibility to establish metrological traceability of the measurements of CO2 isotopic composition is a key aspect, and greatly relies on the availability of gaseous reference materials having compositions and uncertainties that are fit for purpose. In the past years, INRiM participated in the EMPIR project 16ENV06 SIRS “Metrology for stable isotope reference standards”, and is now taking part in the EMPIR project 19ENV05 STELLAR “Stable isotope metrology to enable climate action and regulation”. INRiM has experience in the preparation of gas standards by primary methods, namely gravimetry and dynamic dilution, which can be applied to the realisation of reference materials of CO2 at known isotopic composition. The present work describes the preliminary results obtained by INRiM in the preparation of pure CO2 RMs and at atmospheric amount fraction. Examples of uncertainty budgets and identification of the uncertainty sources are also give

tDCS and Robotics on Upper Limb Stroke Rehabilitation: Effect Modification by Stroke Duration and Type of Stroke

Objective. The aim of this exploratory pilot study is to test the effects of bilateral tDCS combined with upper extremity robot-assisted therapy (RAT) on stroke survivors. Methods. We enrolled 23 subjects who were allocated to 2 groups: RAT + real tDCS and RAT + sham-tDCS. Each patient underwent 10 sessions (5 sessions/week) over two weeks. Outcome measures were collected before and after treatment: (i) Fugl-Meyer Assessment-Upper Extremity (FMA-UE), (ii) Box and Block Test (BBT), and (iii) Motor Activity Log (MAL). Results. Both groups reported a significant improvement in FMA-UE score after treatment (p<0.01). No significant between-groups differences were found in motor function. However, when the analysis was adjusted for stroke type and duration, a significant interaction effect (p<0.05) was detected, showing that stroke duration (acute versus chronic) and type (cortical versus subcortical) modify the effect of tDCS and robotics on motor function. Patients with chronic and subcortical stroke benefited more from the treatments than patients with acute and cortical stroke, who presented very small changes. Conclusion. The additional use of bilateral tDCS to RAT seems to have a significant beneficial effect depending on the duration and type of stroke. These results should be verified by additional confirmatory studies

Realisation and validation of a dilution device for the generation of different isotopic compositions of CO2

Il presente rapporto tecnico descrive l’attività svolta all’INRIM nell’ambito del progetto EMPIR 16ENV06 “Metrology for Stable Isotope Reference Standards - SIRS”, per la realizzazione di un sistema di diluizione dinamica atto a generare materiali di riferimento di CO2 a frazioni molari a livello atmosferico, aventi differente composizione isotopica nell’intervallo (-48/ -8) ‰ VPDB per il δ13C e (-27/ +2) ‰ VPDB per il δ18O. Lo scopo di questa attività è stata la realizzazione di un sistema per generare miscele aventi composizione isotopica e incertezze obiettivo analoghe ai materiali di riferimento “statici” realizzati nel progetto SIRS. Questi materiali di riferimento dinamici verranno utilizzati per validare i materiali di riferimento statici e per studiare la stabilità e il frazionamento delle miscele. La validazione, descritta nel presente rapporto tecnico, è stata incentrata in particolare sullo studio delle prestazioni della camera di miscelamento, che rappresenta il cuore del sistema di diluizione. Il sistema è stato testato in termini di frazione molare, mediante un analizzatore infrarosso non dispersivo. Le miscele di CO2 a frazione molare ambiente, generate all’interno della camera, hanno mostrato una buona ripetibilità con valori di scarto tipo pari a (0.18-0.20 μmol·mol-1). La validazione in termini di composizione isotopica sarà oggetto di un successivo rapporto tecnico.This technical report describes the activity carried out at INRIM within the EMPIR project 16ENV06 “Metrology for Stable Isotope Reference Standards - SIRS”, for the realisation of a dilution device for generating dynamic reference materials of CO2 at ambient mole fractions, with different isotopic compositions to cover the range (-48 to -8) ‰ vs VPDB for δ13C and (-27 to +2) ‰ vs VPDB for δ18O. The aim of the activity was to realise a system to generate mixtures with isotopic composition and target uncertainties as the static reference materials realised in the SIRS project. These dynamic reference materials will be used to validate the static reference materials and to study stability and fractionation of the mixtures. The validation of the dilution system, described in the present technical report, was focused on the performances of the mixing chamber, which represents the core of the system. The system was tested in terms of amount fraction, by using a Non-Dispersive Infrared analyser. The CO2 mixtures at ambient amount fraction, produced inside the chamber, proved to be repeatable with standard deviations of (0.18-0.20 μmol·mol-1). The validation in terms of isotopic composition will be described in a subsequent technical report

Realisation and preliminary validation of a dilution device for the generation of CO2 gas mixtures

The present paper describes the activity carried out at Istituto Nazionale di Ricerca Metrologica (INRIM) within the EMPIR Joint Research Project 16ENV06 “Metrology for Stable Isotope Reference Standards - SIRS”, for the realisation of a dilution device for generating dynamic mixtures of CO2 at ambient mole fractions. The aim of the activity was to realise a system able to generate mixtures with isotopic composition and target uncertainties as the static gravimetric reference materials realised in the SIRS project. These dynamic reference materials can be used to validate the static reference materials and for stability and fractionation studies. The dilution system was realised and a preliminary validation was carried out, focusing on the performances of the mixing chamber, which represents the core of the system. The system was tested in terms of amount fraction, by using a Non-Dispersive Infrared analyser