Atmospheric Pressure Non-thermal Plasma for Air Purification: Ions and Ionic Reactions Induced by dc+ Corona Discharges in Air Contaminated with Acetone and Methanol

Atmospheric pressure mass spectrometry (APCI-MS) was used to investigate the positive ions in air containing acetone (A), methanol (M) and mixtures thereof (A + M), subjected to +dc corona discharges. The results of experiments with isotopically labelled analogues, perdeuterated acetone Adeu and methanol Mdeu, and relevant thermochemical data found in the literature allowed us to identify the main ionic reactions occurring in single component systems (A or M) and in binary mixtures (A + M). It is concluded that, thanks to its significantly higher proton affinity, A is very efficient in quenching M-derived ions at atmospheric pressure. These conclusions provide a rationale for interpreting the results of a parallel investigation on the reciprocal effects of M and A when treated together in air at atmospheric pressure with +dc corona in a non-thermal plasma reactor developed previously in our laboratory. Specifically, we observed a marked drop in the degradation efficiency of methanol when it was treated in the presence of an equivalent amount of acetone. This effect is attributed to acetone interfering with ion-initiated degradation processes of methanol, and supports the conclusion\ua0that ions and ionic reactions are important in dc+ corona induced oxidation of volatile organic pollutants in air

Use of Foundry Sands in the Production of Ceramic and Geopolymers for Sustainable Construction Materials

The aim of this research was to evaluate the possibility of reusing waste foundry sands derived from the production of cast iron as a secondary raw material for the production of building materials obtained both by high-temperature (ceramic tiles and bricks) and room-temperature (binders such as geopolymers) consolidation. This approach can reduce the current demand for quarry sand and/or aluminosilicate precursors from the construction materials industries. Samples for porcelain stoneware and bricks were produced, replacing the standard sand contained in the mixtures with waste foundry sand in percentages of 10%, 50%, and 100% by weight. For geopolymers, the sand was used as a substitution for metakaolin (30, 50, 70 wt%) as an aluminosilicate precursor rather than as an aggregate to obtain geopolymer pastes. Ceramic samples obtained using waste foundry sand were characterized by tests for linear shrinkage, water absorption, and colorimetry. Geopolymers formulations, produced with a Si/Al ratio of 1.8 and Na/Al = 1, were characterized to evaluate their chemical stability through measurements of pH and ionic conductivity, integrity in water, compressive strength, and microstructural analysis. The results show that the addition of foundry sand up to 50% did not significantly affect the chemical-physical properties of the ceramic materials. However, for geopolymers, acceptable levels of chemical stability and mechanical strength were only achieved when using samples made with 30% foundry sand as a replacement for metakaolin

Does exist a correlation between endometriosis and thrombophilic disorders? A pilot study

OBJECTIVE: At present, there is growing evidence of the existence of a genetic predisposition in both thrombophilic disorders and endometriosis. The aim of our study was to evaluate for the first time the prevalence of some thrombophilic disorders in patients with endometriosis. MATERIALS AND METHODS: We conducted a retrospective study on 138 patients with endometriosis and 278 healthy control women. All women were subjected to a blood examination testing for thrombophilic screening and the variables examinated were: hyperhomocysteinemia, factor V Leiden and factor II prothrombin G20210A mutations in heterozygosis and homozigosis. RESULTS: A significant reduced prevalence (p < 0.05) of factor V Leiden mutation in endometriosis patients was found, whereas no significant differences (p = NS) for factor II and hyperhomocysteinemia were observed. CONCLUSION: Our preliminary data do not show any association between thrombophilic condition and endometriosis. Before assuming hormonal therapies, a thrombophilic plasmatic screening seems to be unnecessary in patients affected by endometriosis

Cooperation between Prostaglandin E2 and Epidermal Growth Factor Receptor in Cancer Progression: A Dual Target for Cancer Therapy

It is recognized that prostaglandin E2 (PGE2) is one key lipid mediator involved in chronic inflammation, and it is directly implicated in tumor development by regulating cancer cell growth and migration, apoptosis, epithelial–mesenchymal transition, angiogenesis, and immune escape. In addition, the expression of the enzymes involved in PGE2 synthesis, cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase 1 (mPGES1), positively correlates with tumor progression and aggressiveness, clearly indicating the crucial role of the entire pathway in cancer. Moreover, several lines of evidence suggest that the COX2/mPGES1/PGE2 inflammatory axis is involved in the modulation of epidermal growth factor receptor (EGFR) signaling to reinforce the oncogenic drive of EGFR activation. Similarly, EGFR activation promotes the induction of COX2/mPGES1 expression and PGE2 production. In this review, we describe the interplay between COX2/mPGES1/PGE2 and EGFR in cancer, and new therapeutic strategies that target this signaling pathway, to outline the importance of the modulation of the inflammatory process in cancer fighting. © 2023 by the authors

Efficiency, products and mechanisms of ethyl acetate oxidative degradation in air non-thermal plasma

Ethyl acetate (EA) is a popular solvent and diluent in many products and one of the most ubiquitous organic pollutants of indoor air. Although EA's ascertained toxicity is classified as low, exposure to its vapors at concentrations 400 ppm causes serious problems in humans. EA is thus a frequent target in testing novel technologies for air purification. We report here an investigation of EA oxidative degradation in air at room temperature and atmospheric pressure induced by corona discharges. Three corona regimes, dc-, dc+ and pulsed +, were tested in the same reactor under various experimental conditions with regard to EA initial concentration (C 0) and the presence of humidity in the system. The EA degradation process was monitored by gas chromatography (GC)-flame ionization detection, GC-mass spectrometry and Fourier transform infrared spectroscopy analysis of the treated gas. These analyses yielded the concentration of residual EA (C) and those of its major products of oxidation (CO2, CO) and revealed a few organic reaction intermediates formed along the oxidation chain. The process energy efficiency was determined as energy constant, k E (kJ-1 l) and as energy yield, EY (g kW-1 h-1). The efficiency depends on the type of corona (pulsed + >dc- >dc+), on the presence of humidity in the air (improvement in the case of dc-, little or no effect for dc+) and on C 0 (k E increases linearly with 1/C 0). CO2 and CO were the major carbon containing products, confirming the strong oxidizing power of air non-thermal plasma. Acetic acid and acetaldehyde were detected in very small amounts as reaction intermediates. The experimental results obtained in this work support the conclusion that different reactive species are involved in the initial step of EA oxidation in the case of dc- and dc+ corona air non-thermal plasma

Exploiting the potential of large eddy simulations (LES) for ducted fuel injection investigation in non-reacting conditions

The diesel combustion research is increasingly focused on ducted fuel injection (DFI), a promising concept to abate engine-out soot emissions in compression-ignition engines. A large set of experiments carried out in constant volume vessel and numerical simulations, at medium-low computational cost, showed that the duct adoption in front of the injector nozzle activates several soot mitigation mechanisms, leading to quasi-zero soot formation in several engine-like operating conditions. However, although the simplified CFD modelling so far played a crucial role for the preliminary understanding of DFI technology, a more accurate turbulence description approach, combined with a large set of numerical experiments for statistical purposes, is of paramount importance for a robust knowledge of the DFI physical behaviour. In this context, the present work exploits the potential of large eddy simulations (LES) to analyse the non-reacting spray of DFI configuration compared with the unconstrained spray. For this purpose, a previously developed spray model, calibrated and validated in the RANS framework against an extensive amount of experimental data related to both free spray and DFI, has been employed. The tests have been carried out considering a single-hole injector in an optical accessible constant volume vessel, properly replicated in the simulation environment. This high-fidelity simulation model has been adapted for LES, firstly selecting the best grid settings, and then carrying out several numerical experiments for both spray configurations until achieving a satisfying statistical convergence. With this aim, the number of independent samples for the averaging procedure has been increased exploiting the axial symmetry characteristics of the present case study. Thanks to this approach, a detailed description of the main DFI-enabled soot mitigation mechanisms has been achieved, shrinking the knowledge gap in the physical understanding of the impact of spray-duct interaction

Comment on "water-Soluble Fluorescent Probe with Dual Mitochondria/Lysosome Targetability for Selective Superoxide Detection in Live Cells and in Zebrafish Embryos"

Recently, a new water-soluble, fluorescein-based probe for the detection of superoxide radical anion in aqueous media was developed by Lu et al. (ACS Sens. 2018, 3, 59-64). The probe was proven to be selective for superoxide and was used successfully also in cells and zebrafish embryos. To characterize the response of the probe to superoxide, Lu et al. used KO2 dissolved in deionized water as a surrogate. In testing this probe in different applications, we repeated some of these experiments and came to realize that the fluorescence signal observed by the Authors in their experiments with KO2 was incorrectly attributed to the reaction of the probe with superoxide and is due instead to its reactions with HO- and HO2-. We show that indeed under the conditions used in these assays KO2 undergoes very fast reaction with water to form HO- and HO2-. On the other hand, by using a proper surrogate, namely, KO2 dissolved in DMSO, and spin trapping experiments, we confirmed the ability of the probe to detect superoxide

Microwave-assisted vacuum synthesis of tio2 nanocrystalline powders in one-pot, one-step procedure

A new method for fast and simple synthesis of crystalline TiO2 nanoparticles with photocat-alytic activity was developed by carrying out a classic sol–gel reaction directly under vacuum. The use of microwaves for fast heating of the reaction medium further reduces synthesis times. When the solvent is completely removed by vacuum, the product is obtained in the form of a powder that can be easily redispersed in water to yield a stable nanoparticle suspension, exhibiting a comparable photocatalytic activity with respect to a commercial product. The present methodology can, therefore, be considered a process intensification procedure for the production of nanotitania

Kinetics and Products of Air Plasma Induced Oxidation in Water of Imidacloprid and Thiamethoxam Treated Individually and in Mixture

Imidacloprid (I) and thiamethoxam (T) are widely used neonicotinoid insecticides with high persistence in the environment and thus included in the watch list of substances for European Union-wide monitoring reported in the Decision 2015/495/EU. In this work aqueous solutions of I, T and I + T were subjected to advanced oxidation by air plasma produced by negative DC corona discharges above the liquid surface. The oxidative degradation of each pollutant was investigated by monitoring the rate and the products of its decay when treated alone and in the presence of variable amounts of the other compound. The results show that both I and T are readily degraded and that mineralization can be achieved in this process, as proven by the measurement of the residual organic carbon and by the quantitative conversion of chlorine and sulfur into inorganic chloride and sulfate, respectively. The major organic intermediates formed during the complex stepwise oxidation of I and T were identified and monitored by HPLC\u2013MS/MS analysis. The results of kinetic studies show that both for I and T the reaction rate depends inversely on the insecticide initial concentration, that I and T have similar reactivities and that they do not interfere reciprocally in any specific way when treated in mixture at a total concentration of ca 1 7 10 124 M. Based on literature data and on previous results with the same reactor, it is reasonable to propose that the oxidation of I and T is initiated by the reaction with OH radicals