Tungsten (VI) oxide particles (WO3, <100 nm particle size) are used for many purposes including production of electro chromic windows, or smart windows, x-ray screen phosphors and gas sensors in everyday life. However, the carcinogenic and genotoxic potential of this nanomaterial have not been sufficiently evaluated. Therefore, the genotoxic potential of WO3was examined in Sprague-Dawley rat bone marrow cells by using mitotic index (MI), micronucleus (MN) and chromosome aberrations (CA) assays. Rats were orally gavaged with a single dose of WO3(0, 25, 50 and 100 mg/kg) for 30 days. All WO3treatments significantly decreased MI rates as compared to the control group. No increase in the incidence of CA was observed at any WO3nanoparticle dose in the CA test although MN formation was significantly (P<0.05) increased for 50 and 100 mg/kg doses. The observed alterations in MN and MI parameters reveal that WO3has cytotoxic and genotoxic potential and could pose environmental and human health risk.

Aging effects of porous silicon (PS) and the origin of blue shift are investigated. Photoluminescence (PL) measurements of the PS prepared with HF-EtOH solution showed a 210 meV blue shift after 1.5 months. It is found from deconvolution of the PL spectra that this shift is not fully related to the quantum confinement (QC) effect. For stable PS formation, a HFEtOH-H2O2 solution is used. A stable luminescence at 2.01 eV with a Gaussian distribution is obtained when the samples are kept in H2O2 for 45 min after the anodization.

This paper presents fabrication and characterization of ridge waveguide InGaAs/InGaAsP/InP lasers with an operating wavelength of 1.5m using reactive ion etching (RIE), chemically assisted ion beam etching (CAIBE) and wet etching techniques. Characterization results of the lasers with 2m-wide waveguides are given of the two etching methods comparatively using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), L-I-V (Light-current-voltage) and spectral measurement techniques. Additionally, a comparison of wet and RIE etched lasers with 20m-wide waveguide is also discussed. Highly smooth (2.1+0.4nm rms surface roughness) and vertical (~90o) structures are obtained using RIE, in which the 2m-wide fabricated devices exhibit better performance over the CAIBE etched ones.

Cryo-soft X-ray tomography (cryo-SXT) is a powerful method to investigate the ultrastructure of cells, offering resolution in the tens of nanometer range and strong contrast for membranous structures without requiring labeling or chemical fixation. The short acquisition time and the relatively large field of view leads to fast acquisition of large amounts of tomographic image data. Segmentation of these data into accessible features is a necessary step in gaining biologically relevant information from cryo-soft X-ray tomograms. However, manual image segmentation still requires several orders of magnitude more time than data acquisition. To address this challenge, we have here developed an end-to-end automated 3D segmentation pipeline based on semisupervised deep learning. Our approach is suitable for high-throughput analysis of large amounts of tomographic data, while being robust when faced with limited manual annotations and variations in the tomographic conditions. We validate our approach by extracting three-dimensional information on cellular ultrastructure and by quantifying nanoscopic morphological parameters of filopodia in mammalian cells.

Nanoparticles (NPs) are used in various forms in consumer products including, cosmetics, food packaging, textiles and also in air and water cleaning, production of electro chromic windows, or smart windows and gas sensors. Many NPs have also been evaluated for potential use in biomedical applications as efficient delivery carriers for cancer diagnosis and therapy. Nowadays, NPs are being developed to create fascinating nanotechnology products. To develop NPs for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration. Again, to translate these nanomaterials to the clinic and industrial domains, their biosafety needs to be verified, particularly in terms of genotoxic and carcinogenic effects. To evaluate evidenced-based practices for NPs safety, we performed a systematic review of the published English-language literature. We performed a systematic keyword search of PubMed for original research articles pertaining to reports on assessment of risks due to carcinogenic and mutagenic effects by different NPs. We identified 362 original articles available for analysis. The included studies were published between 1993 and 2012. The in vivo or in vitro genotoxicity studies were performed on only 18 out of 148 kinds of NPs in industry today. Likewise, the carcinogenicity investigations were performed on only 14 out of 148 NPs. The 10 types of the NPs including some titanium, aluminium, carbon black and silver molecules were found to have both mutagenic and carcinogenic potential. The important finding was also that there is a lack of systematic assessment of the DNA damaging and carcinogenic potential of NPs in spite of their extensive use in nanotechnological applications.