An in-depth multi-omics analysis in RLE-6TN rat alveolar epithelial cells allows for nanomaterial categorization.

BACKGROUND: Nanomaterials (NMs) can be fine-tuned in their properties resulting in a high number of variants, each requiring a thorough safety assessment. Grouping and categorization approaches that would reduce the amount of testing are in principle existing for NMs but are still mostly conceptual. One drawback is the limited mechanistic understanding of NM toxicity. Thus, we conducted a multi-omics in vitro study in RLE-6TN rat alveolar epithelial cells involving 12 NMs covering different materials and including a systematic variation of particle size, surface charge and hydrophobicity for SiO2 NMs. Cellular responses were analyzed by global proteomics, targeted metabolomics and SH2 profiling. Results were integrated using Weighted Gene Correlation Network Analysis (WGCNA). RESULTS: Cluster analyses involving all data sets separated Graphene Oxide, TiO2_NM105, SiO2_40 and Phthalocyanine Blue from the other NMs as their cellular responses showed a high degree of similarities, although apical in vivo results may differ. SiO2_7 behaved differently but still induced significant changes. In contrast, the remaining NMs were more similar to untreated controls. WGCNA revealed correlations of specific physico-chemical properties such as agglomerate size and redox potential to cellular responses. A key driver analysis could identify biomolecules being highly correlated to the observed effects, which might be representative biomarker candidates. Key drivers in our study were mainly related to oxidative stress responses and apoptosis. CONCLUSIONS: Our multi-omics approach involving proteomics, metabolomics and SH2 profiling proved useful to obtain insights into NMs Mode of Actions. Integrating results allowed for a more robust NM categorization. Moreover, key physico-chemical properties strongly correlating with NM toxicity were identified. Finally, we suggest several key drivers of toxicity that bear the potential to improve future testing and assessment approaches.

SWeRF--A method for estimating the relevant fine particle fraction in bulk materials for classification and labelling purposes.

In accordance with the European regulation for classification, labelling and packaging of substances and mixtures (CLP) as well as the criteria as set out in the Globally Harmonized System (GHS), fine fraction of crystalline silica (CS) has been classified as a specific target organ toxicity, the specific organ in this case being the lung. Generic cut-off values for products containing a fine fraction of CS trigger the need for a method for the quantification of the fine fraction of CS in bulk materials. This article describes the so-called SWeRF method, the size-weighted relevant fine fraction. The SWeRF method combines the particle size distribution of a powder with probability factors from the EN 481 standard and allows the relevant fine fraction of a material to be calculated. The SWeRF method has been validated with a number of industrial minerals. This will enable manufacturers and blenders to apply the CLP and GHS criteria for the classification of mineral products containing RCS a fine fraction of CS.

[Silica classification and labelling under REACH and CLP regulation]. / Il problema della classificazione ed etichettatura della silice cristallina alla luce del REACH e del regolamento CLP.

Following literature data the evaluation CLP classification and labelling criteria doesn't support the decision to classify respirable crystalline silica (RCS) as carcinogen and suggests to consider RCS as:--STOT (Specific Target Organ Toxicant) RE (Repeated Exposure) cat.l by inhalation in case of concentration > or = 10%--STOT RE cat. 2 by inhalation in case of concentration 1 divided by 10%--Not classifiable as dangerous for human in case of concentration < 1%.

The nanosilica hazard: another variable entity.

Silica nanoparticles (SNPs) are produced on an industrial scale and are an addition to a growing number of commercial products. SNPs also have great potential for a variety of diagnostic and therapeutic applications in medicine. Contrary to the well-studied crystalline micron-sized silica, relatively little information exists on the toxicity of its amorphous and nano-size forms. Because nanoparticles possess novel properties, kinetics and unusual bioactivity, their potential biological effects may differ greatly from those of micron-size bulk materials. In this review, we summarize the physico-chemical properties of the different nano-sized silica materials that can affect their interaction with biological systems, with a specific emphasis on inhalation exposure. We discuss recent in vitro and in vivo investigations into the toxicity of nanosilica, both crystalline and amorphous. Most of the in vitro studies of SNPs report results of cellular uptake, size- and dose-dependent cytotoxicity, increased reactive oxygen species levels and pro-inflammatory stimulation. Evidence from a limited number of in vivo studies demonstrates largely reversible lung inflammation, granuloma formation and focal emphysema, with no progressive lung fibrosis. Clearly, more research with standardized materials is needed to enable comparison of experimental data for the different forms of nanosilicas and to establish which physico-chemical properties are responsible for the observed toxicity of SNPs.

Identification of granite varieties from colour spectrum data.

The granite processing sector of the northwest of Spain handles many varieties of granite with specific technical and aesthetic properties that command different prices in the natural stone market. Hence, correct granite identification and classification from the outset of processing to the end-product stage optimizes the management and control of stocks of granite slabs and tiles and facilitates the operation of traceability systems. We describe a methodology for automatically identifying granite varieties by processing spectral information captured by a spectrophotometer at various stages of processing using functional machine learning techniques.

Phytoliths in woody plants from the Miombo woodlands of Mozambique.

BACKGROUND AND AIMS: There are no descriptions of phytoliths produced by plants from the 'Zambezian' zone, where Miombo woodlands are the dominant element of the largest single phytochorion in sub-Saharan Africa. The preservation of phytoliths in fossil records of Africa makes phytoliths a tool to study early plant communities. Paleo-ethnobotanical interpretation of phytoliths relies on the comparison of ancient types with morphotypes extracted from living reference collections. METHODS: Phytoliths were extracted from plant samples representing 41 families, 77 genera and 90 species through sonic cleaning, dry ashing and acid treatment; and phytoliths thus extracted were quantified. For each species, an average of 216 phytoliths were counted. The percentage of each morphotype identified per species was calculated, and types were described according to the descriptors from the International Code for Phytolith Nomenclature. Phytolith assemblages were subject to discriminant analysis, cluster analysis and principal component analysis. KEY RESULTS: Phytoliths were grouped into 57 morphotypes (two were articulated forms and 55 were discrete shapes), and provide a reference collection of phytolith assemblages produced by Miombo woody species. Common and unique morphotypes are described and taxonomic and grouping variables are looked into from a statistical perspective. CONCLUSIONS: The first quantitative taxonomy of phytoliths from Miombos is presented here, including new types and constituting the most extensive phytolith key for any African ecoregion. Evidence is presented that local woody species are hypervariable silica producers and their phytolith morphotypes are highly polymorphic. The taxonomic significance of these phytoliths is largely poor, but there are important exceptions that include the morphotypes produced by members from >10 families and orders. The typical phytolithic signal that would allow scientists to identify ancient woodlands of 'Zambezian' affiliation comprises only half of the original number of phytoliths originally produced and might favour the more resilient blocky, cylindroid, globular and tabular forms.

International code for phytolith nomenclature 1.0.

BACKGROUND: Phytoliths (microscopic opal silica particles produced in and between the cells of many plants) are a very resilient, often-preserved type of microfossil and today, phytolith analysis is widely used in palaeoenvironmental studies, botany, geology and archaeology. To date there has been little standardization in the way phytoliths are described and classified. SCOPE: This paper presents the first International Code for Phytolith Nomenclature (ICPN), proposing an easy to follow, internationally accepted protocol to describe and name phytoliths.

Soil reinforcement with recycled carpet wastes.

A root or fibre-reinforced soil behaves as a composite material in which fibres of relatively high tensile strength are embedded in a matrix of relatively plastic soil. Shear stresses in the soil mobilize tensile resistance in the fibres, which in turn impart greater strength to the soil. A research project has been undertaken to study the influence of synthetic fibrous materials for improving the strength characteristics of a fine sandy soil. One of the main objectives of the project is to explore the conversion of fibrous carpet waste into a value-added product for soil reinforcement. Drained triaxial tests were conducted on specimens, which were prepared in a cylindrical mould and compacted at their optimum water contents. The main test variables included the aspect ratio and the weight percentage of the fibrous strips. The results clearly show that fibrous inclusions derived from carpet wastes improve the shear strength of silty sands. A model developed to simulate the effect of the fibrous inclusions accurately predicts the influence of strip content, aspect ratio and confining pressure on the shear strength of reinforced sand.

Radioelement distributions in the Proterozoic granites and associated pegmatites of Gabal El Fereyid area, Southeastern Desert, Egypt.

Lithologically, the rock types in the Gabal El Fereyid area are dominantly granites with minor amounts of pegmatites. The granites range in composition from tonalite to granite-adamallite with minor acidic dikes, quartz and pegmatite veins. The granite-adamallite is peraluminous and formed as a result of partial melting of amphibole-bearing rocks at depths of approximately 24-30 km and at temperatures of 800-950 degrees C. Among the different rock types, the muscovite-rich pegmatites had the highest U and Th contents (66 and 38 ppm on average, respectively). The high level of radioactivity in pegmatites is attributed to the presence of the radioactive minerals thorianite, uranophane and allanite as confirmed by XRD analysis. Binary relations of Zr/U, Zr/Th, Ce/U and Ce/Th against either U or Th in the granite-adamellite exhibit significant negative correlations indicating that both elements are not preferentially hosted in the accessory minerals phases such as zircon and monazite, but could be associated with major forming minerals such as biotite, muscovite, plagioclase and quartz, or U is situated within labile sites within granite. The uranium and thorium enrichment in the pegmatites is a two-stage process. The primary stage is magmatic whereas the secondary enrichment is from hydrothermal concentration. The magmatic U and Th are indicated by the presence of thorianite and allanite, whereas evidence of hydrothermal mineralization is the alteration of rock-forming minerals such as feldspar and the formation of secondary minerals such as uranophane and pyrite.

Hydrophobicity of templated silica xerogels for molecular sieving applications.

Silica xerogels were prepared by a sol-gel process catalyzed by acid with tetraethylorthosilicate, and using an organic covalent ligand template (methyltriethoxysilane) or a noncovalent template C6 surfactant (triethylhexylammonium bromide). The influence of hydrotreatment on the structure of templated xerogels is examined in terms of surface area, micropore volume, average pore size, and pore size distribution, and compared against a blank xerogel (nontemplated). The role of surface functional groups was evaluated using 29Si nuclear magnetic resonance. The structural integrity of the xerogel was maintained to a large extent in samples that had a high contribution of Q4 species (siloxane groups). Xerogel matrix densification occurred when there was a large concentration of Q3 and Q2 species (silanol groups), which also were responsible for increased hydrophilicity. The templated xerogels resulted in up to a 25% concentration of methyl functional groups (T3 and T2 species), leading to hydrophobic xerogels. The best results in terms of structural integrity and hydrophobicity were obtained with templated xerogels prepared with the C6 surfactant. The results in this study suggest that surfactant-enhanced condensation reactions lead to structures with a high contribution of Q4 groups, which are not susceptible to water attack, but are strong enough to oppose matrix densification during rehydration.

A laboratory simulation of toluene cleanup by air sparging of water-saturated sands.

Laboratory air sparging experiments were performed in narrow acrylic tanks to evaluate the cleanup of toluene in water-saturated sands. Air flow channels in the sediment were identified by way of a colorimetric visualization technique, which allowed pore water samples to be collected at a known horizontal distance from an air channel. Pore water was sampled at periodic intervals during sparging experiments and analyzed by gas chromatography to yield toluene concentration vs. time data. Results indicate that channelized air flow is effective in reducing toluene concentrations in the range of 36-3 ppm, within 2 to 5 days, at least up to 185 mm from an active air channel. While relatively rapid, these toluene reduction times are longer than previously published data, from similar type experiments. The discrepancy is likely a function of air delivery flow rate and proximity of sampling sites to active air channels. Data from the current investigation were used to attempt an estimate of effective diffusion coefficients (D*) for toluene in clean, well-characterized sands in which the concentration gradient was imposed by sparge air. Calculated D* values range from 2. 98x10(-8) m(2)/s to 5.74x10(-9) m(2)/s, and are significantly faster than previously published values of toluene diffusion in clay soils. However, the values are also slightly greater than diffusion coefficients for toluene in aqueous solutions, indicating that the calculations more likely estimate coefficients of hydrodynamic dispersion (D(L)).

Amorphous silica: a review of health effects from inhalation exposure with particular reference to cancer.

Silicas and silicates are some of the most abundant compounds found naturally in the earth's crust. Excessive exposure to crystalline silicas can cause serious lung disease such as silicosis and has been associated with lung cancer in some studies, but the potential health effects of amorphous silicas (silicon dioxide without crystalline structure) have not been well studied. Results from animal studies of amorphous silicas, unlike those seen with crystalline silicas, have suggested limited and largely reversible cytotoxic and possibly fibrogenic effects associated with some forms, but data on cancer outcomes are scanty and for the most part negative. Epidemiologic investigations to date for any potential cancer risk are not informative because the effects of crystalline and amorphous silicas have not been separated. Any future epidemiologic study should attempt to clarify the health effects of amorphous silicas from those of crystalline silicas, particularly with regard to any potential for carcinogenicity.

Differential pulmonary responses in rats inhaling crystalline, colloidal or amorphous silica dusts.

Pulmonary responses in rats were compared after short-term inhalation exposure to polymorphs of silica dust. Groups of CD rats were exposed 6 h a day for 3 d to crystalline silica or amorphous silica. Another group was exposed to Ludox colloidal silica for 6 h a day, 5 d a week for two or four weeks. Thereafter the groups were killed, and the lungs washed at several postexposure times. The crystalline silica produced persistent pulmonary inflammatory responses characterized by neutrophil recruitment and consistently elevated biomarkers of cytotoxicity in bronchoalveolar lavage fluids, and progressive histopathological lesions were observed within one month of the exposure. Amorphous silica produced a transient pulmonary inflammatory response, and Ludox elicited transient pulmonary inflammatory responses at 50 or 150 mg center dot m-3 but not at 10 mg center dot m-3. After three months most of the biochemical values of the Ludox-exposed animals had returned to the control level. These results demonstrate that crystalline silica dust is more potent in producing pulmonary toxicity when compared with amorphous or colloidal silica particles.