Acute and repeated exposures of normal human bronchial epithelial (NHBE) cells culture to particles from a coloured pyrotechnic smoke.

Coloured pyrotechnic smokes are frequently used in the military field and occasionally by civilians, but their health hazards have been little studied. The main concern could rise from inhalation of smoke particles. Our previous study showed that acute exposure to particles from a red signalling smoke (RSS) induced an antioxidant and inflammatory responses in small airway epithelial cells. The aim of this study was to further explore the toxicity of RSS particles at a more proximal level of the respiratory tract, using normal human bronchial epithelial cells grown at the Air-Liquid Interface. Acute exposure (24 h) induced an oxidative stress that persisted 24 h post-exposure, associated with particle internalization and epithelium morphological changes (cuboidal appearance and loss of cilia). Repeated exposures (4×16h) to RSS particles did not trigger oxidative stress but cell morphological changes occurred. Overall, this study provides a better overview of the toxic effects of coloured smoke particles.

Large Interactive Touchscreens as an Opportunity for Synchronous Hybrid Teaching during the COVID-19 Pandemic and Beyond.

The year 2020 will be remembered as the year of COVID-19 and its subsequent lockdowns. The time to return to face-to-face teaching has arrived, but the shadow of the disease still hangs over teachers, students, and society. Disruption in teaching can still occur for students, or even teachers, if they are either diagnosed as COVID-19 positive or as a contact case and forced to self-isolate. In order to limit the impact of self-isolation on learning, synchronous hybrid teaching (i.e., teaching face to face to students in a classroom and to students online at the same time) was successfully implemented owing to the combination of video conference software and a large interactive touchscreen. The setup presented in this paper allows courses to be broadcast to students at home (i.e., voice, visual pedagogic support, and, more interestingly, indications handwritten by the teacher) as well as simultaneously teaching to students in the classroom face-to-face. It also allows self-isolated teachers to teach tutorials from their home to students in the classroom. This paper focuses on the use of large interactive touchscreens for synchronous hybrid teaching and its evaluation by students using a questionnaire. The key findings of this study are that students prefer synchronous hybrid teaching rather than missing a course and that synchronous hybrid teaching should only be used in case of absolute necessity.

Oxidative potential and in vitro toxicity of particles generated by pyrotechnic smokes in human small airway epithelial cells.

Pyrotechnic smokes are widely used in civilian and military applications. The major issue arise from the release of particles after smoke combustion but the health risks related to their exposure are poorly documented whereas toxicity of airborne particles on the respiratory target are very well known. Therefore, this study aimed to explore the in vitro toxicity of the particle fraction of different pyrotechnic smokes. Particles from a red signalling smoke (RSS), an hexachloroethane-based obscuring smoke (HC-OS) and an anti-intrusion smoke (AIS) were collected from the cloud. RSS particles displayed the highest organic fraction (quinones and polycyclic aromatic hydrocarbons) of the three samples characterized. AIS particles contained K and cholesterol derivatives. HC-OS particles were mainly metallic with very high concentrations of Al, Fe and Ca. Intrinsic oxidative potential of smoke particles was measured with two assays. Depletions of DTT by RSS particles was greater than depletion obtained with AIS and HC-OS particles but depletion of acid ascorbic (AA) was only observed with HC-OS particles. In vitro toxicity was assessed by exposing human small airway epithelial cells (SAEC) to various concentrations of particles. After 24 h of exposure, cell viability was not affected but significant modifications of mRNA expression of antioxidant (SOD-1 and -2, catalase, HO-1, NQO-1) and inflammatory markers (IL-6, IL-8, TNF-α) were observed and were dependent on smoke type. Particles rich in metal, such as HC-OS, induced a greatest depletion of AA and a greatest inflammatory response, whereas particles rich in organic compounds, such as RSS, induced a greatest DTT depletion and a greatest antioxidant response. In conclusion, the three smoke particles have an intrinsic oxidative potential and triggered a cell adaptive response. Our study improved the knowledge of particle toxicity of pyrotechnic smokes and scientific approach developed here could be used to study other type of particles.

Application of Doehlert experimental design for the removal of radium from aqueous solution by cross-linked phenoxycalix[4]pyrrole-polymer using Ba(II) as a model.

Ra-226 is a naturally occurring radionuclide that is derived from uranium-238 series, and it is present at low concentrations in rocks, soil, and groundwater. Many efforts have been exerted for the decontamination of radium from aqueous media in order to meet the increasing water demand of the population. To this aim, a new polymer based on cross-linked phenoxycalix[4]pyrrole was designed and employed in solid/liquid extractions in order to remove radium from aqueous solutions. Preliminary experiments have highlighted the capability of this polymer to extract 22% of Ra-226 from aqueous acidic solution. The optimization of the extraction experimental factors in the direction to attend the maximum removal of Ra-226 from water was carried out employing Ba2+ due to its similar chemical behavior as radium, in order to minimize the consumption of Ra-226 solutions and the risk of radioactive contamination. Doehlert experimental plan was then applied to determine the optimal conditions (pH, time, temperature) for the removal of Ba2+ from aqueous solutions.

Solid-liquid extraction of iodide and bromide from aqueous media by a new water-insoluble phenoxycalix[4]pyrrole-epichlorohydrin polymer.

The present study describes the synthesis of the first phenoxycalix[4]pyrrole-epichlorohydrin based polymer. The advantage of the latter resides in its fast-single step synthesis protocol, low cost, water insolubility and its unexpected anion extraction capacity. The study of this polymer by various solid/liquid extractions with halides in aqueous solutions and quantitative ion chromatography analysis showed that unlike other calix[4]pyrrole-based entities, this polymer extracts iodide rather than bromide and fluoride owing to the presence of large extraction pockets. Evidence of an anion exchange process involving preferably chloride and bromide was also highlighted.

A click mediated route to a novel fluorescent pyridino-extended calix[4]pyrrole sensor: synthesis and binding studies.

A novel fluorescent aryl-extended phenoxycalix[4]pyrrole ditopic sensor with enhanced cation recognition properties was efficiently synthesized via click chemistry and characterized through both molecular fluorescence and nuclear magnetic resonance spectroscopy. Results demonstrate the selectivity of this fluorescent sensor for fluoride when taking into account its interaction with anions, while its cation binding properties showed selectivity for iron, and its sensing properties for several cations in dimethylsulfoxide. This work introduces a new ditopic receptor able to complex major environmentally relevant species and depicts the importance of click chemistry in the introduction of new tetra-chromophoric calix[4]pyrrole binding platforms with specific photophysical properties.

Efficient synthesis of 4-substituted-ortho-phthalaldehyde analogues: toward the emergence of new building blocks.

4-Methoxy-ortho-phthalaldehyde and 4-hydroxy-ortho-phthalaldehyde are potentially useful molecules for fluorimetric analysis of a variety of amines and for the elaboration of complex molecular architectures. Nevertheless, literature generally describes their synthesis in very low yield (below 5%), mainly due to the inefficiency of the last oxidation step. In this paper, we report a reliable synthesis of 4-substituted-ortho-phthalaldehyde analogues in 51% overall yield owing to the addition of a protecting step of the unstable key intermediate 4,5-dihydroisobenzofuran-5-ol. Oxidation and deprotection steps were also studied in order to provide an effective availability of these two dialdehyde compounds that may increase their future applications.

Ultrasound-Assisted Heterogeneous Synthesis of Bio-Based Oligo-Isosorbide Glycidyl Ethers: Towards Greener Epoxy Precursors.

The substitution of toxic precursors such as bisphenol A by renewable and safer molecules has become a major challenge. To overcome this challenge, the 12 principles of green chemistry should be taken into account in the development of future sustainable chemicals and processes. In this context, this paper reports the highly efficient synthesis of oligo-isosorbide glycidyl ethers from bio-based starting materials by a rapid one-pot heterogeneous ultrasound-assisted synthesis. It was demonstrated that the use of high-power ultrasound in solvent-free conditions with sodium hydroxide microbeads led for the first time to a fully epoxidated prepolymer with excellent epoxy equivalent weight (EEW). The structure of the epoxy precursor was characterized by FT-IR, NMR spectroscopy and high-resolution mass spectrometry (HRMS). The efficiency of the ultrasound-assisted synthesis was attributed to the physical effects caused by micro-jets on the surface of the solid sodium hydroxide microspheres following the asymmetrical collapse of cavitation bubbles.

Recognition of iron ions by carbazole-desferrioxamine fluorescent sensor and its application in total iron detection in airbone particulate matter.

This work reports on an efficient microwave irradiation synthesis of a new fluorescent chemosensor based on desferrioxamine B (DFO-B) and carbazole moiety. Furthermore, this novel chemosensor was employed for a comparative study of real environmental samples of airbone particulate matter collected from Dunkirk (Northern of France). Among selected relevant metal cations present in its airbone particulate matter, such as Na(+), K(+), Mg(2+), Ca(2+), Al(3+), Cr(3+), Mn(2+) and Zn(2+), this molecular device proved to be outstandingly sensitive toward Fe(3+) with a limit of detection of 1.49 ppb (2.1×10(-8) M) in methanol allowing the estimation of total iron in atmospheric particles.

Ultrasound-promoted tosylation of oligo(ethylene glycols).

A series of oligo(ethylene glycols) was efficiently tosylated by ultrasound procedure within dichloromethane in the presence of triethylamine. Results show that sonochemical synthesis of oligo(ethylene glycol) ditosylates has a double advantage since it does not use catalysts and it drastically reduces the reaction time. This straightforward method represents an eco-friendly alternative to the traditional tosylation by pyridine synthesis.