3D-structured supports create complete data sets for electron crystallography.

3D electron crystallography has recently attracted much attention due to its complementarity to X-ray crystallography in determining the structure of compounds from submicrometre sized crystals. A big obstacle lies in obtaining complete data, required for accurate structure determination. Many crystals have a preferred orientation on conventional, flat sample supports. This systematically shades some part of the sample and prevents the collection of complete data, even when several data sets are combined. We introduce two types of three-dimensional sample supports that enable the collection of complete data sets. In the first approach the carbon layer forms coils on the sample support. The second approach is based on chaotic nylon fibres. Both types of grids disrupt the preferred orientation as we demonstrate with a well suited crystal type of MFI-type zeolites. The easy-to-obtain three-dimensional sample supports have different features, ensuring a broad spectrum of applications for these 3D support grids.

Airborne Nanoparticle Release and Toxicological Risk from Metal-Oxide-Coated Textiles: Toward a Multiscale Safe-by-Design Approach.

Nano metal oxides have been proposed as alternatives to silver (Ag) nanoparticles (NPs) for antibacterial coatings. Here, cotton and polyester-cotton fabrics were sonochemically coated with zinc oxide (ZnO) and copper oxide (CuO) NPs. By varying the reaction solvent (water or ethanol), NPs with different sizes and shapes were synthesized. The cytotoxic and pro-inflammatory effects of studied NPs were investigated in vitro in human alveolar epithelial A549 and macrophage-like THP1 cells. To understand the potential respiratory impact of the NPs, the coated textiles were subjected to the abrasion tests, and the released airborne particles were measured. A very small amount of the studied metal oxides NPs was released from abrasion of the textiles coated by the ethanol-based sonochemical process. The release from the water-based coating was comparably higher. Lung and immune cells viability decreased after 24 h of exposure only at the highest studied NPs concentration (100 µg/mL). Different from the ZnO NPs, both formulations of CuO NPs induced IL-8 release in the lung epithelial cells already at subtoxic concentrations (1-10 µg/mL) but not in immune cells. All of the studied NPs did not induce IL-6 release by the lung and immune cells. Calculations revealed that the exposures of the NPs to human lung due to the abrasion of the textiles were lower or comparable to the minimum doses in the cell viability tests (0.1 µg/mL), at which acute cytotoxicity was not observed. The results alleviate the concerns regarding the potential risk of these metal oxide NPs in their applications for the textile coating and provide insight for the safe-by-design approach.

Organic dye removal by MnO2 and Ag micromotors under various ambient conditions: The comparison between two abatement mechanisms.

MnO2- and Ag- based micromotors were developed recently as new types of micromotors with the advantage of low costs and have been utilized to treat environmental pollutants. However, knowledge about the effects of ambient conditions on the performance of them is still lacking. In this article, the influences of pH, electrolytes and surfactant on the treatment of organic dye (with methylene blue as the representative) by the commercial MnO2 and Ag micromotors with H2O2 as the fuel were studied. In the motion visualization experiments, besides the routine types of trajectories, the circular motion of micromotors around the already formed bubbles was observed for the first time. In the pollutant removal experiments, two abatement mechanisms (catalytic degradation and adsorptive bubble separation) were studied. The decolorization efficiency for MnO2 due to catalytic degradation increased with the increasing pH, which disagreed with previous studies in which no H2O2 was added. The inhibitory effects of the tested electrolytes were in the order: CaCl2>NaNO3>NaCl. Surfactant can increase the decolorization efficiency only under highly alkaline conditions. For Ag, decolorization only occurs with the existence of surfactant at high pH values (pH = 11.4) indicating that the dominant mechanism is adsorptive bubble separation.

Agglomeration potential of TiO2 in synthetic leachates made from the fly ash of different incinerated wastes.

Material flow studies have shown that a large fraction of the engineered nanoparticles used in products end up in municipal waste. In many countries, this municipal waste is incinerated before landfilling. However, the behavior of engineered nanoparticles (ENPs) in the leachates of incinerated wastes has not been investigated so far. In this study, TiO2 ENPs were spiked into synthetic landfill leachates made from different types of fly ash from three waste incineration plants. The synthetic leachates were prepared by standard protocols and two types of modified procedures with much higher dilution ratios that resulted in reduced ionic strength. The pH of the synthetic leachates was adjusted in a wide range (i.e. pH 3 to 11) to understand the effects of pH on agglomeration. The experimental results indicated that agglomeration of TiO2 in the synthetic landfill leachate simultaneously depend on ionic strength, ionic composition and pH. However, when the ionic strength was high, the effects of the other two factors were masked. The zeta potential of the particles was directly related to the size of the TiO2 agglomerates formed. The samples with an absolute zeta potential value < 10 mV were less stable, with the size of TiO2 agglomerates in excess of 1500 nm. It can be deduced from this study that TiO2 ENPs deposited in the landfill may be favored to form agglomerates and ultimately settle from the water percolating through the landfill and thus remain in the landfill.