European standard on small punch testing of metallic materials

In the 1980s, studying the effect of neutron irradiation and temper embrittlement on structural materials for the fusion and fission programmes was a major challenge. In this context the development of small specimen test techniques began, allowing the characterization of structural materials for nuclear applications with small amounts of material. The small punch technique is of one these small specimen test approaches. It is widely used for the development and monitoring of structural materials, however there is currently no comprehensive international standard for small punch testing. An EN standard on small punch testing is currently being developed under the auspices of ECISS/TC101/WG1. Besides describing the apparatus, procedures, and specimens, it will include recommendations for the estimation of tensile, fracture and creep properties from small punch testing as well as machine readable formats for representing and transferring test data. This paper describes the current status of the standard and highlights some of the changes with regard to the current CWA 15672 (2007)

Integrated miRNA and mRNA analysis of time series microarray data

The dynamic temporal regulatory effects of microRNA are not well known. We introduce a technique for integrating miRNA and mRNA time series microarray data with known disease pathology. The integrated analysis includes identifying both mRNA and miRNA that are signi cantly similar to the quantitative pathology. Potential regulatory miRNA/mRNA target pairs are identi ed through databases of both predicted and validated pairs. Finally, potential target pairs are ltered by examining the second derivatives of the fold changes over time. Our system was used on genome-wide microarray expression data of mouse lungs (n = 160) following aspiration of multi-walled carbon nanotubes. This system shows promise of readily identifying miRNA for further study as potential biomarker use

Integrated miRNA and mRNA Analysis of Time Series Microarray Data

The dynamic temporal regulatory effects of microRNA are not well known. We introduce a technique for integrating miRNA and mRNA time series microarray data with known disease pathology. The integrated analysis includes identifying both mRNA and miRNA that are signi cantly similar to the quantitative pathology. Potential regulatory miRNA/mRNA target pairs are identi ed through databases of both predicted and validated pairs. Finally, potential target pairs are ltered by examining the second derivatives of the fold changes over time. Our system was used on genome-wide microarray expression data of mouse lungs (n = 160) following aspiration of multi-walled carbon nanotubes. This system shows promise of readily identifying miRNA for further study as potential biomarker use

Multi-walled carbon nanotube-induced gene expression in vitro: concordance with in vivo studies

There is a current interest in reducing the in vivo toxicity testing of nanomaterials in animals by increasing toxicity testing using in vitro cellular assays; however, toxicological results are seldom concordant between in vivo and in vitro models. This study compared global multi-walled carbon nanotube (MWCNT)-induced gene expression from human lung epithelial and microvascular endothelial cells in monoculture and coculture with gene expression from mouse lungs exposed to MWCNT. Using a cutoff of 10% false discovery rate and 1.5 fold change, we determined that there were more concordant genes (gene expression both up- or downregulated in vivo and in vitro) expressed in both cell types in coculture than in monoculture. When reduced to only those genes involved in inflammation and fibrosis, known outcomes of in vivo MWCNT exposure, there were more disease-related concordant genes expressed in coculture than monoculture. Additionally, different cellular signaling pathways are activated in response to MWCNT dependent upon culturing conditions. As coculture gene expression better correlated with in vivo gene expression, we suggest that cellular cocultures may offer enhanced in vitro models for nanoparticle risk assessment and the reduction of in vivo toxicological testing

mRNA and miRNA regulatory networks reflective of multi-walled carbon nanotube-induced lung inflammatory and fibrotic pathologies in mice

Multi-walled carbon nanotubes (MWCNTs) are known for their transient inflammatory and progressive fibrotic pulmonary effects; however, the mechanisms underlying these pathologies are unknown. In this study, we used time-series microarray data of global lung mRNA and miRNA expression isolated from C57BL/6J mice exposed by pharyngeal aspiration to vehicle or 10, 20, 40, or 80 µg MWCNT at 1, 7, 28, or 56 days post-exposure to determine miRNA and mRNA regulatory networks that are potentially involved in MWCNT-induced inflammatory and fibrotic lung etiology. Using a non-negative matrix factorization method, we determined mRNAs and miRNAs with expression profiles associated with pathology patterns of MWCNT-induced inflammation (based on bronchoalveolar lavage score) and fibrosis (based on Sirius Red staining measured with quantitative morphometric analysis). Potential binding targets between pathology-related mRNAs and miRNAs were identified using Ingenuity Pathway Analysis and the miRTarBase, miRecords, and TargetScan databases. Using these experimentally validated and predicted binding targets, we were able to build molecular signaling networks that are potentially reflective of and play a role in MWCNT-induced lung inflammatory and fibrotic pathology. As understanding the regulatory networks between mRNAs and miRNAs in different disease states would be beneficial for understanding the complex mechanisms of pathogenesis, these identified genes and pathways may be useful for determining biomarkers of MWCNT-induced lung inflammation and fibrosis for early detection of disease

Lung Microtissue Array to Screen the Fibrogenic Potential of Carbon Nanotubes

Due to their excellent physical and chemical characteristics, multi-wall carbon nanotubes (MWCNT) have the potential to be used in structural composites, conductive materials, sensors, drug delivery and medical imaging. However, because of their small-size and light-weight, the applications of MWCNT also raise health concerns. In vivo animal studies have shown that MWCNT cause biomechanical and genetic alterations in the lung tissue which lead to lung fibrosis. To screen the fibrogenic risk factor of specific types of MWCNT, we developed a human lung microtissue array device that allows real-time and in-situ readout of the biomechanical properties of the engineered lung microtissue upon MWCNT insult. We showed that the higher the MWCNT concentration, the more severe cytotoxicity was observed. More importantly, short type MWCNT at low concentration of 50 ng/ml stimulated microtissue formation and contraction force generation, and caused substantial increase in the fibrogenic marker miR-21 expression, indicating the high fibrogenic potential of this specific carbon nanotube type and concentration. The presented microtissue array system provides a powerful tool for high-throughput examination of the therapeutic and toxicological effects of target compounds in realistic tissue environment