Long-term dust generation from silicon carbide powders

Most dustiness studies do not measure dust release over long durations, nor do they characterize the effect of dust release on bulk powders. In this study, we tested the dustiness of two different samples of silicon carbide (SiC) powders (referred to as F220 and F320) over six hours using a vortex shaker. Additionally, we characterized the bulk sample for change in shape and size distribution due to the testing. Both powders release respirable fractions of dust particles but differ in their dust generation behavior. The numbers of released respirable particles for powder F220 are more than two times higher than those of powder F320. The dust generation mechanism might include the release of aerosols due to the attrition of particles owing to inter-particle and particle-wall impaction. This study emphasizes the need for long duration dustiness tests for hard materials like SiC and characterization for change in bulk material properties due to dust generation and release. Furthermore, the results can aid in selecting the bulk material for long-term applications based on dustiness

Molecular mechanisms redirecting the GLP-1 receptor signalling profile in pancreatic β-cells during type 2 diabetes

International audienc

Bilateral uveitis and macular edema induced by Nivolumab: a case report

Abstract Background Nivolumab is a fully human antibody which is routinely used at first therapy for metastatic melanoma. Usually, side effects are immune-related adverse events. We report a case of a man who developed bilateral anterior uveitis and macular serous retinal detachment during nivolumab treatment for metastatic melanoma. Case presentation A man on nivolumab treatment for a leg melanoma with duodenal and lymph nodes metastases developed a sudden bilateral visual acuity impairment and bilateral non-painfull redness eyes several days after the third infusion. The clinical examination showed a significant decreased of the visual acuity. Slit lamp examination revealed the presence of bilateral granulomatous keratic precipitates, anterior chamber cells +++, bilateral synechiae, bilateral papilledema and macular edema associated with serous retinal detachment in the left eye. The anti-Programmed cells Death-1 was stopped and a topical corticosteroid treatment was administrated. After 8 days of topical corticosteroid treatment visual acuity was worsening with similar optical coherence tomography examination. An oral corticosteroid treatment was started. Evolution was favorable with a decrease of ocular inflammation and a complete visual acuity recovery after 3 weeks. Nivolumab was re-initiated. Conclusions This is the second clinical report of bilateral anterior uveitis associated with macular serous retinal detachment related to anti-PD-1 treatment, and the first with nivolumab. Cases of uveitis were reported several times. Although rare, ophthalmologic manifestations that are rapidly recognized and adequately managed can be treated

Bilateral uveitis and macular edema induced by Nivolumab: a case report

Abstract Background Nivolumab is a fully human antibody which is routinely used at first therapy for metastatic melanoma. Usually, side effects are immune-related adverse events. We report a case of a man who developed bilateral anterior uveitis and macular serous retinal detachment during nivolumab treatment for metastatic melanoma. Case presentation A man on nivolumab treatment for a leg melanoma with duodenal and lymph nodes metastases developed a sudden bilateral visual acuity impairment and bilateral non-painfull redness eyes several days after the third infusion. The clinical examination showed a significant decreased of the visual acuity. Slit lamp examination revealed the presence of bilateral granulomatous keratic precipitates, anterior chamber cells +++, bilateral synechiae, bilateral papilledema and macular edema associated with serous retinal detachment in the left eye. The anti-Programmed cells Death-1 was stopped and a topical corticosteroid treatment was administrated. After 8 days of topical corticosteroid treatment visual acuity was worsening with similar optical coherence tomography examination. An oral corticosteroid treatment was started. Evolution was favorable with a decrease of ocular inflammation and a complete visual acuity recovery after 3 weeks. Nivolumab was re-initiated. Conclusions This is the second clinical report of bilateral anterior uveitis associated with macular serous retinal detachment related to anti-PD-1 treatment, and the first with nivolumab. Cases of uveitis were reported several times. Although rare, ophthalmologic manifestations that are rapidly recognized and adequately managed can be treated

Aerosol nanostructure study with porous grids - A review

The study of particle morphology is a key step in risk assessment related to the inhalation of nanoparticles. The analysis is generally ensured by TEM (Transmission Electronic Microscope). Up-tonow, using porous TEM grid is one of the easiest technique to provide samples. On the one hand, the present communication reviews applications using the technique, and on the other hand, provides feedback from the state of the art to support the set of sampling time, which is a key parameter for users. The sampling on porous grid technique has been introduced by VTT (Lyyränen 2009) and assessed by INERIS developing and using a Mini Particle Sampler (MPS, www.ecomesure.com), both in a theoretical and experimental point of view (R’mili 2013). AIST (Ogura 2014) confirmed these results. The main interest of this technique is that the sampling support is also the support of analysis. The MPS sampler is low cost, portable and easy to use. The grid is immediately available for analysis as soon as the sampling is stopped. A state of the art about the use of MPS shows there is a growing number of applications. Regarding nanosafety, the MPS is carried out for exposure assessment at the workplace as well as the study of emissions from powder handling, dustiness testing, mechanical solicitation of end-products, processes (e.g. deposit of nanoparticles on textiles), exposure of consumer, end of life (e.g. characterization of incineration fumes), characterization of exposure during in vivo and in vitro toxicological studies, etc. Some Guidance or future Standards are supporting the use of MPS. Applications appear also in other fields, such as car exhausts, road particle release, exposure in cars, air quality in clean rooms, worker exposure to diesel fumes or brakes emissions, etc. The sampling time is an important parameter to consider for providing good samples to the microscopist. It is recommended to each user of MPS to feed-back his own experience from his specific sampling conditions. Such an approach is illustrated on the Figure below where optimized sampling time has been plotted versus the related total number concentration provided by a CPC in the submicronic range. This feed-back is based mostly on studies conducted at a flow rate of 0.3 lpm in various contexts. As a result, the operator can assess the order of magnitude of the sampling time by using the total number concentration measured simultaneously in real time

Determination of the UFP_3031 Uncertainty on Number Concentration regarding Ambient Air Particle Monitoring

From 2011 onwards, some French regional air quality monitoring networks started to develop strategies for the monitoring of airborne ultraFine particles. To ensure the consistency of the results obtained from these various programs, a single measurement technique has been commonly selected, the Model 3031 Ultrafine Particle (UFP) Monitor. Objective of the study : Two interlaboratory exercises have been organized in 2014 and 2015, to assess the accuracy of the instrument through a comparison with other techniques (such as Scanning Mobility Particle Sizer, SMPS), and through uncertainty calculations. Instrumentation : The UFP 3031 is manufactured by TOPAS and commercialized by TSI. It measures the size distribution and number concentration within six particle size classes between 20 and 800 nm. The principle is based on diffusion charging of particles, followed by size segregation within a Differential Mobility Analyzer (DMA) and detection of the aerosol via an electrometer. It has been specifically designed for long-term, air quality monitoring networks. It operates with minimal maintenance, requires no working fluids and has no radioactive source. It is easily installed into existing air quality monitoring stations..

Evaluation des risques pour l'opérateur au cours d'essais d'explosivité de nanopoudres en laboratoire

A qualitative risk assessment was performed by control banding with CB Nanotool and StoffenManager Nano during explosiveness testing of carbon black and MWCNT. Exposure of the operator was also measured. The results enabled to highlight a few sources of nanomaterials emission during the tests. It led also to the finding that the dynamic barrier provided by the local exhaust ventilation system can be temporarily weakened during overpressure events. Comparison of the measurements with the risk assessment results enabled to assess the relevance of the two control banding tools.Une évaluation qualitative des risques a été réalisée par control banding avec CB Nanotool et StoffenManager Nano au cours d'essais d'explosivité de nanopoudres carbonées. L'exposition de l'opérateur a également été mesurée. Les résultats ont permis d'identifier quelques sources potentielles d'émission de NMx. Ils ont aussi montré que la barrière dynamique générée par l'aspiration de la sorbonne pouvait être temporairement affaiblie lors de la dépressurisation de la sphère. La comparaison des risques estimés avec les mesures a permis d'évaluer la pertinence des deux outils d'évaluation graduée des risques utilisés

La surveillance des particules ultrafines en France

Measurement of ultrafine particles (UFP) has been developing recently in the air quality monitoring networks in France. These particles are very small in size (<100 nm) and low in mass, but represent significant health effects. This article presents different results of short and long-term measurement campaigns which have been carried out in different environments (urban, traffic and industry) and the comparison of the number concentrations and size distribution at the national level. In addition, we show how UFPs measurements can be used to identify local sources and explain atmospheric phenomena.La mesure des particules ultrafines (PUF) se développe de plus en plus dans les réseaux de surveillance de la qualité de l’air en France. Ces particules sont très petites en taille (<100 nm) et faibles en masse, mais représentent des effets sanitaires importants. Cet article présente différents résultats issus de campagnes de mesure de courte et longue durée qui ont été réalisées dans différents environnements (urbain, trafic et industrie), et une comparaison des concentrations en nombre et de la distribution en taille au niveau national. De plus, nous montrons comment la mesure de PUF peut permettre d’identifier des sources locales et contribuer à expliquer certains phénomènes atmosphériques