Absence of genotoxicity following pulmonary exposure to metal oxides of copper, tin, aluminum, zinc, and titanium in mice.

Inhalation of nanosized metal oxides may occur at the workplace. Thus, information on potential hazardous effects is needed for risk assessment. We report an investigation of the genotoxic potential of different metal oxide nanomaterials.

Mass and Mobility of Ions Produced by Radioactive Sources and Corona Discharges.

Positive and negative ions produced by radioactive sources and corona discharges in gases find a number of applications, including charging aerosol particles prior to their measurement by electrical and/or electrical mobility techniques. The degree to which these ions can charge aerosol particles depends on their mobility and mass; properties that are strongly affected by the composition of the carrier gas and the impurities that it contains. We show that when the purity of the carrier gas is increased, the mobility of both positive and negative ions increases by more than 50%, whereas the respective masses reduce by more than 50%.

Bioinspired nanostructured hydroxyapatite-polyelectrolyte multilayers for stone conservation.

Stone-built cultural heritage faces threats from natural forces and anthropogenic pollutants, including local climate, acid rain, and outdoor conditions like temperature fluctuations and wind exposure, all of which impact their structural integrity and lead to their degradation. The development of a water-based, environmentally-friendly protective coatings that meet a combination of requirements posed by the diversity of the substrates, different environmental conditions, and structures with complex geometries remains a formidable challenge, given the numerous obstacles faced by current conservation strategies. Here we report the structural, electrical, and mechanical characterization, along with performance testing, of a nanostructured hydrophilic and self-healing hybrid coating based on hydroxyapatite (HAp) nanocrystals and polyelectrolyte multilayers (PEM), formed in-situ on Greek marble through a simple spray layer-by-layer surface functionalization technique.

Indoor and outdoor air quality in street corner kiosks in a large metropolitan area.

Poor air quality in workplaces constitutes a great concern on human health as a good fraction of our time is spent at work. In Greece, very unique workplaces are the street corner kiosks, which are freestanding boxes placed on sidewalks next to city streets and vehicular traffic, where one can find many consumer goods. As such, its employees are exposed to both outdoor and indoor air pollutants.

Electronic properties and collision cross sections of AgOH (, = 1-4) aerosol ionic clusters.

Experimental evidence shows that hydroxylated metal ions are often produced during cluster synthesis by atmospheric pressure spark ablation. In this work, we predict the ground state equilibrium structures of AgOH clusters ( and = 1-4), which are readily produced when spark ablating Ag, using the coupled cluster with singles and doubles (CCSD) method. The stabilization energy of these clusters is calculated with respect to the dissociation channel having the lowest energy, by accounting perturbative triples corrections to the CCSD method.

Submicron aerosol pollution in Greater Cairo (Egypt): A new type of urban haze?

Greater Cairo, the largest megacity of the Middle East North Africa (MENA) region, is currently suffering from major aerosol pollution, posing a significant threat to public health. However, the main sources of pollution remain insufficiently characterized due to limited atmospheric observations. To bridge this knowledge gap, we conducted a continuous 2-month field study during the winter of 2019-2020 at an urban background site, documenting for the first time the chemical and physical properties of submicron (PM) aerosols.

Tuning atomic-scale mixing of nanoparticles produced by atmospheric-pressure spark ablation.

Nanoparticles (NPs) mixed at the atomic scale have been synthesized by atmospheric-pressure spark ablation using pairs of Pd and Hf electrodes. Gravimetric analysis of the electrodes showed that the fraction of each material in the resulting mixed NPs can be varied from 15-85 at% to 85-15 at% by employing different combinations of electrode polarities and thicknesses. These results were also qualitatively corroborated by microscopy and elemental analysis of the produced NPs.

Adsorption of air pollutants onto silver and gold atomic clusters: DFT and PNO-LCCSD-F12 calculations.

We provide a comprehensive investigation of intermolecular interactions between atmospheric gaseous pollutants, including CH, CO, CO, NO, NO, SO, as well as HO and Ag ( = 1-22) or Au ( = 1-20) atomic clusters. The optimized geometries of all the systems investigated in our study were determined using density functional theory (DFT) with M06-2X functional and SDD basis set. The PNO-LCCSD-F12/SDD method was used for more accurate single-point energy calculations.

Gas-Phase Interaction of CO, CO, HS, NH, NO, NO, and SO with ZnO and Zn Atomic Clusters.

Atmospheric pollutants pose a high risk to human health, and therefore it is necessary to capture and preferably remove them from ambient air. In this work, we investigate the intermolecular interaction between the pollutants such as CO, CO, HS, NH, NO, NO, and SO gases with the Zn and ZnO atomic clusters, using the density functional theory (DFT) at the meta-hybrid functional TPSSh and LANl2Dz basis set. The adsorption energy of these gas molecules on the outer surfaces of both types of clusters has been calculated and found to have a negative value, indicating a strong molecular-cluster interaction.

Comparison of acute phase response in mice after inhalation and intratracheal instillation of molybdenum disulphide and tungsten particles.

Inhalation studies are the gold standard for assessing the toxicity of airborne materials. They require considerable time, special equipment, and large amounts of test material. Intratracheal instillation is considered a screening and hazard assessment tool as it is simple, quick, allows control of the applied dose, and requires less test material.

Genotoxicity in the absence of inflammation after tungsten inhalation in mice.

Tungsten is used in several applications and human exposure may occur. To assess its pulmonary toxicity, we exposed male mice to nose-only inhalation of tungsten particles at 9, 23 or 132 mg/m (Low, Mid and High exposure) (45 min/day, 5 days/week for 2 weeks). Increased genotoxicity (assessed by comet assay) was seen in bronchoalveolar (BAL) fluid cells at Low and High exposure.

Pulmonary toxicity of molybdenum disulphide after inhalation in mice.

Molybdenum disulphide (MoS) is a constituent of many products. To protect humans, it is important to know at what air concentrations it becomes toxic. For this, we tested MoS particles by nose-only inhalation in mice.

Electronic Structure, Stability, and Electrical Mobility of Cationic Silver Oxide Atomic Clusters.

Silver oxide cluster cations (AgO) can readily be produced by a number of methods including atmospheric-pressure spark ablation of pure silver electrodes when trace amounts of oxygen are present in the carrier gas. Here we determine the equilibrium geometries of AgO clusters ( = 1-4; = 1-5) using accurate coupled cluster with singles and doubles (CCSD) method, while the stabilization energies are calculated with additional perturbative triples correction (CCSD(T)). Although a number of stable states have been identified, our results show that the AgO clusters with = 1 are more stable than those with ≥ 2 due to the absence of the terminally attached O molecule, corroborating recent observations by mass spectrometry.

Performance evaluation of a 3D-printed sharp-cut cyclone.

A sharp-cut cyclone with an aerodynamic cut-off diameter of 1 μm, when operated at a flow rate of 1 L min, was built by 3D-printing and tested against a metallic (aluminum) counterpart having the same design and dimensions. The penetration efficiency of both cyclones was experimentally determined using quasi-monodisperse aerosol particles having aerodynamic diameters from 100 nm to 2 μm. The aerodynamic cut-off diameter for both cyclones was very similar and in accordance with the expected design value.

Metal oxide semiconducting nanomaterials for air quality gas sensors: operating principles, performance, and synthesis techniques.

To meet requirements in air quality monitoring, sensors are required that can measure the concentration of gaseous pollutants at concentrations down to the ppb and ppt levels, while at the same time they exhibiting high sensitivity, selectivity, and short response/recovery times. Among the different sensor types, those employing metal oxide semiconductors (MOSs) offer great promises as they can be manufactured in easy/inexpensive ways, and designed to measure the concentration of  a wide range of target gases. MOS sensors rely on the adsorption of target gas molecules on the surface of the sensing material and the consequent capturing of electrons from the conduction band that in turn affects their conductivity.

Thin Film and Nanostructured Pd-Based Materials for Optical H Sensors: A Review.

In this review paper, we provide an overview of state-of-the-art Pd-based materials for optical H sensors. The first part of the manuscript introduces the operating principles, providing background information on the thermodynamics and the primary mechanisms of optical detection. Optical H sensors using thin films (i.

New method for the protection and restoration of calcareous cultural heritage stones by polyelectrolytes and hydroxyapatite nanocrystals.

We have investigated the feasibility of a new two-step protocol for the restoration of marbles. The process employs a polyelectrolyte multilayer film that enhances the chemical affinity between the treated stone and restorative material (hydroxyapatite nanocrystals), through functionalization, while at the same time it attributes an acid resistant property to the resulting system. Surface functionalization and material deposition is achieved through spraying; a simple and versatile application method suitable for objects of various sizes and geometries.

Estimation of the emissions by transport in two port cities of the northeastern Mediterranean, Greece.

Air pollution is one of the most important branches of environmental science as it affects human health, climate and ecosystems. Emissions of air pollutants from transport (vehicles and ships) in port cities strongly affect air quality at local scales, warranting for a combination of theoretical and experimental studies to identify pollution hotspots. The purpose of this paper is to provide a methodology for developing a hybrid emission inventory from transport sector for two port cities located respectively on the Northern Aegean islands of Chios and Lesvos.

Workplace Exposure to Nanoparticles during Thermal Spraying of Ceramic Coatings.

Thermal spraying is widely used for industrial-scale application of ceramic coatings onto metallic surfaces. The particular process has implications for occupational health, as the high energy process generates high emissions of metal-bearing nanoparticles. Emissions and their impact on exposure were characterized during thermal spraying in a work environment, by monitoring size-resolved number and mass concentrations, lung-deposited surface area, particle morphology, and chemical composition.

Airborne ultrafine particles in a naturally ventilated metro station: Dominant sources and mixing state determined by particle size distribution and volatility measurements.

Ultrafine particle number concentrations and size distributions were measured on the platform of a metro station in Athens, Greece, and compared with those recorded at an urban background station. The volatility of the sampled particles was measured in parallel, providing further insights on the mixing state and composition of the sampled particles. Particle concentration exhibited a mean value of 1.

Can disc diffusion susceptibility tests assess the antimicrobial activity of engineered nanoparticles?

The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test, namely the Kirby-Bauer disc diffusion test, to determine the antimicrobial activity of Au and Ag ENPs having diameters from 10 to 40 nm on cultures. As anticipated, the tests did not show any antibacterial effects of Au nanoparticles (NPs) as a result of their negligible diffusivity through the culture media.

Magnetic Phase Transition in Spark-Produced Ternary LaFeSi Nanoalloys.

Using the magnetocaloric effect in nanoparticles holds great potential for efficient refrigeration and energy conversion. The most promising candidate materials for tailoring the Curie temperature to room temperature are rare-earth-based magnetic nanoalloys. However, only few high-nuclearity lanthanide/transition-metal nanoalloys have been produced so far.

Hot Carrier Generation and Extraction of Plasmonic Alloy Nanoparticles.

The conversion of light to electrical and chemical energy has the potential to provide meaningful advances to many aspects of daily life, including the production of energy, water purification, and optical sensing. Recently, plasmonic nanoparticles (PNPs) have been increasingly used in artificial photosynthesis (e.g.

Long-term observations of the background aerosol at Cabauw, The Netherlands.

Long-term measurements of PM mass concentrations and aerosol particle size distributions from 2008 to 2015, as well as hygroscopicity measurements conducted over one year (2008-2009) at Cabauw, The Netherlands, are compiled here in order to provide a comprehensive dataset for understanding the trends and annual variabilities of the atmospheric aerosol in the region. PM concentrations have a mean value of 14.4μgm with standard deviation 2.