Atomic spectrometry update : a review of advances in environmental analysis

This is the 31st annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This update refers to papers published approximately between August 2014 and July 2015 and continues the series of Atomic Spectrometry Updates (ASUs) in Environmental Analysis that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages; advances in atomic spectrometry and related techniques; elemental speciation; X-ray spectrometry; and metals, chemicals and functional materials. In the field of air analysis, highlights within this review period included: the development of a new laser fluorescence instrument for the ultratrace determination of mercury vapour; single particle ICP-MS studies and the coupling of elemental analysers to mass spectrometers for the improved characterisation of carbonaceous aerosols. In the arena of water analysis, methods continue to be developed: for the extraction and preconcentration of elements, As, Cr, Hg and Sb species and determination of elemental constituents in colloidal and NP fractions. Emerging elements of interest include Gd derived from MRI agents discharged at low level from medical facilities in water courses. Instrumental developments reported included the use of MC-ICP-MS for isotopic tracer studies and a review of TXRF techniques and associated preconcentration procedures for trace element analysis. In the period covered by this update several articles have explored the analysis of soil extracts for geochemical prospecting. There has been widening interest in the use of CS-AAS and in the application of techniques capable of direct sample analysis such as slurry sampling ETAAS and ETV-ICP-AES. Portable XRF instrumentation is now being used in many disciplines to quantify trace elements in soils – bringing a need for better transfer of analytical knowledge to non-specialist users – and the growing use of portable XRF in proximal sensing is also noteworthy. Recent research indicates that geological applications still drive many of the instrumental and methodological advances in LA-ICP-MS. Fundamental studies continued to shed light on the processes involved and hence ways of improving the analysis of laser-produced aerosols and to minimise matrix and fractionation effects. A new technique LA-DOF-MS (distance of flight) was described. The utility of LIBS and portable XRF for in situ survey work continues to show promise but issues such as appropriate calibration regimes and data processing protocols will still need to be addressed

Correction: Spatiotemporal distribution and speciation of silver nanoparticles in the healing wound.

Correction for 'Spatiotemporal distribution and speciation of silver nanoparticles in the healing wound' by Marco Roman et al., Analyst, 2020, 145, 6456–6469, DOI: 10.1039/D0AN00607F

Calibration and assessment of electrochemical low-cost sensors in remote alpine harsh environments

This work presents results from an original open-source low-cost sensor (LCS) system developed to measure tropospheric O3 in a remote high altitude alpine site. Our study was conducted at the Col Margherita Observatory (2543 m above sea level), in the Italian Eastern Alps. The sensor system mounts three commercial low-cost O3/NO2 sensors that have been calibrated before field deployment against a laboratory standard (Thermo Scientific; 49i-PS), calibrated against the standard reference photometer no. 15 calibration scale of the World Meteorological Organization (WMO). Intra- and intercomparison between the sensors and a reference instrument (Thermo Scientific; 49c) have been conducted for 7 months from May to December 2018. The sensors required an individual calibration, both in laboratory and in the field. The sensor's dependence on the environmental meteorological variables has been considered and discussed. We showed that it is possible to reduce the bias of one LCS by using the average coefficient values of another LCS working in tandem, suggesting a way forward for the development of remote field calibration techniques. We showed that it is possible reconstruct the environmental ozone concentration during the loss of reference instrument data in situations caused by power outages. The evaluation of the analytical performances of this sensing system provides a limit of detection (LOD) 0.8, bias >3.5 ppb and ±8.5 at 95 % confidence. This first implementation of a LCS system in an alpine remote location demonstrated how to obtain valuable data from a low-cost instrument in a remote environment, opening new perspectives for the adoption of low-cost sensor networks in atmospheric sciences.publishedVersio

Assessment of a procedure to determine trace and major elements in Atmospheric Aerosol

The determination of trace elements in atmospheric particulate is affected by a number of problems that arise from some critical points such as the blank of the filters, sample heterogeneity and pre-analytical treatments. In the framework of a monitoring campaign conducted in the Venice Lagoon the analytical methodology for the determination of 20 trace elements (Al, As, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Sr, V, Zn) in atmospheric particulate samples by inductively coupled plasma quadrupole mass spectroscopy (ICP-QMS) has been optimized taking into account the individual critical points. Tests were carried out to estimate the blank contributions, and minimize the detection limit (LOD), measurements were also carried out to evaluate the accuracy and the repeatability. To obtain a complete dissolution of aerosol dust material and good recoveries of the elements, the acid mixture and the microwave assisted digestion program were optimized. The blank contributions from membrane filter manipulation and transportation prior to exposure were tested for the slotted and back filters by placing them on the sampling device for some minutes without air flowing to obtain field blanks (FBs). The contribution to the blank values of passive deposition and by contact with the samplers (quoted as campaign blanks, CBs) was measured by exposing the membranes throughout the sampling session (fifteen days) without any air flow. Instrumental ICP-QMS parameters were optimized and calibration curve intervals were selected on the basis of the necessity of simultaneous determination of the elements present at different levels of concentration. The limits of detection for each elements and the investigated method were suitable to determine the 20 elements reported above in the atmospheric aerosol fractionated in 6 classes ranging between 10 to 0.49 mm. It allows the determination of trace elements in aerosol in a large range of concentrations that can be observed in areas characterized by remarkable variability and regions with different levels of contamination

Cost-Effectiveness of Early Versus Standard Antiretroviral Therapy in HIV-Infected Adults in Haiti

This cost-effectiveness study comparing early versus standard antiretroviral treatment (ART) for HIV, based on randomized clinical trial data from Haiti, reveals that the new WHO guidelines for early ART initiation can be cost-effective in resource-poor settings

Spatiotemporal distribution and speciation of silver nanoparticles in the healing wound

Funding: This research was supported by funds from the MIUR-FIRB project number RBFR08M6W8. Acknowledgments: ELGA LabWater is acknowledged for providing the PURELAB Option-Q and Ultra Analytic systems, which produced the ultra-pure water used for Ag determinations. Adam Douglas and Dhinesh Asogan are acknowledged for their technical support during LA-ICP-MS analysis at the University of Venice, and the authors gratefully acknowledge Bill Spence and Teledyne Cetac Technologies for the loan of the laser ablation instrumentation. Laura Molin and ISTM-CNR are acknowledged for MALDI-TOF-MS analysis. The synchrotron experiments were performed on beamline ID21 at the European Synchrotron Radiation Facility (ESRF), Grenoble, France (proposal #CH4121).Peer reviewedPostprin

Semantic Dementia: a specific network-opathy

Semantic dementia (SD) is a unique syndrome in the frontotemporal lobar degeneration spectrum. Typically presenting as a progressive, fluent anomic aphasia, SD is the paradigmatic disorder of semantic memory with a characteristic anatomical profile of asymmetric, selective antero-inferior temporal lobe atrophy. Histopathologically, most cases show a specific pattern of abnormal deposition of protein TDP-43. This relatively close clinical, anatomical and pathological correspondence suggests SD as a promising target for future therapeutic trials. Here, we discuss outstanding nosological and neurobiological challenges posed by the syndrome and propose a pathophysiological model of SD based on sequential, regionally determined disintegration of a vulnerable neural network