Review of Potential Environmental and Health Risks of the Nanomaterial Graphene

Several future applications have been suggested for the nanomaterial graphene, and its production is increasing dramatically. This study is a review of risk-related information on graphene with the purpose of outlining potential environmental and health risks and guide future risk-related research. Available information is presented regarding emissions, environmental fate, and toxicity of graphene. The results from this study indicate that graphene could exert a considerable toxicity and that considerable emission of graphene from electronic devices and composites are possible in the future. It is also suggested that graphene is both persistent and hydrophobic. Although these results indicate that graphene may cause adverse environmental and health effects, the results foremost show that there are many risk-related knowledge gaps to be filled and that the emissions of graphene, the fate of graphene in the environment, and the toxicity of graphene should be further studied.     

Flows of Chemical Risk Information in the Consumer Paint Product Chain

In this study the flows of chemical risk information for paint as a consumer product were investigated from a product chain perspective. The main method of research involved semi‐structured interviews with Swedish manufacturers of paint and chemicals. In addition, retailers and consumers were interviewed. The flows of chemical risk information between actors within (e.g., manufacturers, retailers, and consumers) and outside (e.g., industry associations and regulators) the paint product chain are described. Because the European chemical legislation REACH (Registration, Evaluation, Authorization and restriction of CHemicals) plays a large role in the management of chemical risk information at companies, some consequences of REACH on actors in the paint product chain are described. Examples of such consequences are that importing of chemicals from non–European Union (EU) countries may be discouraged and that some low‐volume chemicals may no longer be produced. However, manufacturers do not yet see these consequences as impediments to innovation. The results of this work show that chemical risk information is most comprehensive during the manufacturing steps of the product chain. This is due not only to tradition and industry initiatives, but also to REACH and other legislation. The results also illustrate the need for evaluation of how chemical risk information is used in different contexts and the importance of directing the right information at the right target group. Following legislative development, more specialized information is required in the safety data sheet (SDS), and because of this many manufacturers find it necessary to create simplified safety sheets that make the most pertinent safety and hazard information easily accessible to individuals that handle the chemicals in their factories. The study found that in creating the simplified safety sheets, the content and use of chemical risk information is evaluated and adjusted for presentation to this particular target group. It is evident that the Swedish Paint and Printing Ink Makers Association plays an important role in the interpretation of legal requirements and even in agreements for providing information that exceeds legal requirements.     

Profibrinolytic Effect of the Epigenetic Modifier Valproic Acid in Man

Aims

The aim of the study was to test if pharmacological intervention by valproic acid (VPA) treatment can modulate the fibrinolytic system in man, by means of increased acute release capacity of tissue plasminogen activator (t-PA) as well as an altered t-PA/Plasminogen activator inhibitor -1 (PAI-1) balance. Recent data from in vitro research demonstrate that the fibrinolytic system is epigenetically regulated mainly by histone deacetylase (HDAC) inhibitors. HDAC inhibitors, including VPA markedly upregulate t-PA gene expression in vitro.

Methods and Results

The trial had a cross-over design where healthy men (n = 10), were treated with VPA (Ergenyl Retard) 500 mg depot tablets twice daily for 2 weeks. Capacity for stimulated t-PA release was assessed in the perfused-forearm model using intra-brachial Substance P infusion and venous occlusion plethysmography. Each subject was investigated twice, untreated and after VPA treatment, with 5 weeks wash-out in-between. VPA treatment resulted in considerably decreased levels of circulating PAI-1 antigen from 22.2 (4.6) to 10.8 (2.1) ng/ml (p<0.05). It slightly decreased the levels of circulating venous t-PA antigen (p<0.05), and the t-PA:PAI-1 antigen ratio increased (p<0.01). Substance P infusion resulted in an increase in forearm blood flow (FBF) on both occasions (p<0.0001 for both). The acute t-PA release in response to Substance P was not affected by VPA (p = ns).

Conclusion

Valproic acid treatment lowers plasma PAI-1 antigen levels and changes the fibrinolytic balance measured as t-PA/PAI-1 ratio in a profibrinolytic direction. This may in part explain the reduction in incidence of myocardial infarctions by VPA treatment observed in recent pharmacoepidemiological studies.

Trial Registration

The EU Clinical Trials Register 2009-011723-31     

Hydrogels for an accommodating intraocular lens. An explorative study

In this study it was investigated whether hydrogels could be used for an accommodating lens. The requirements of such a hydrogels are a low modulus, high refractive index, transparency, and strength. Since conventional hydrogels do not possess this combination of properties, a novel preparation method and new polymers are introduced. As starting materials poly(1-hydroxy-1,3-propanediyl), poly(ethylene-co-vinyl alcohol), poly(vinyl alcohol), and poly(allyl alcohol) were used. The first three were cross-linked with a number of diisocyanate compounds. Network formation was performed at low concentrations in a good solvent. Mixing of the polymer solution and cross-linker appeared to be crucial for transparency. Poly(1-hydroxy-1,3-propanediyl), cross-linked with a slow reacting diisocyanate block, shows the most promising properties with respect to refractive index, transparency, tensile strength, and modulus. Poly(allyl alcohol) hydrogel was made by compression molding. The hydrogel was transparent and had a high refractive index and low modulus. It was concluded that hydrogels could be used as accommodating lens material.     

piggyBac-based insertional mutagenesis and enhancer detection as a tool for functional insect genomics

Transposon mutagenesis provides a fundamental tool for functional genomics. Here we present a non-species-specific, combined enhancer detection and binary expression system based on the transposable element piggyBac: For the different components of this insertional mutagenesis system, we used widely applicable transposons and distinguishable broad-range transformation markers, which should enable this system to be operational in nonmodel arthropods. In a pilot screen in Drosophila melanogaster, piggyBac mutator elements on the X chromosome were mobilized in males by a Hermes-based jumpstarter element providing piggyBac transposase activity under control of the alpha1-tubulin promoter. As primary reporters in the piggyBac mutator elements, we employed the heterologous transactivators GAL4delta or tTA. To identify larval and adult enhancer detectors, strains carrying UASp-EYFP or TRE-EYFP as secondary reporter elements were used. Tissue-specific enhancer activities were readily observed in the GAL4delta/UASp-based systems, but only rarely in the tTA/TRE system. Novel autosomal insertions were recovered with an average jumping rate of 80%. Of these novel insertions, 3.8% showed homozygous lethality, which was reversible by piggyBac excision. Insertions were found in both coding and noncoding regions of characterized genes and also in noncharacterized and non-P-targeted CG-number genes. This indicates that piggyBac will greatly facilitate the intended saturation mutagenesis in Drosophila.     

Epon Resin Infiltration and Immunogold Labelling of Pituitary Secretory Granules after Cryofixation versus Chemical Fixation

The degree of infiltration of epoxy resin into pituitary secretory granules was evaluated using X-ray microanalysis of the concentrations of chlorine in the epoxy resins. The effectiveness of infiltration was tested after three different tissue preparation techniques: cryofixation + freeze-drying (CF-FD), glutaraldehyde fixation (GF) + chemical dehydration, and no fixation— no dehydration. Signs of marked incomplete infiltration were found in embedded unfixed tissue while the other two techniques showed 80% infiltration. Uneven penetration was seen after CF-FD and GF. The plastic surface demonstrated a mountain-like appearance over the secretory granules after immunocytochemistry of the glutaraldehyde fixed tissue, whereas the CF-FD tissue showed a less furrowed surface. This probably is due to contact with water, which swells those parts of the granules that are unprotected by the plastic embedding medium. Our findings may explain why it is possible to perform immunocytochemistry on Epon embedded tissue.     

A modified drop-net method for sampling mobile epifauna on marine shallow sandy bottoms

The seasonal variations in numbers and biomass of the mobile epifauna of a shallow, sandy bay in Gullmar Fjord (Sweden) was investigated during 1976–1977 using the drop-net technique. Juvenile plaice, Pleuronectes platessa L., sand goby, Pomatoschistus minutus (Pallas), and brown shrimp Crangon crangon L. are the dominant epifaunal species. A net enclosing an area of 100 m² was used, and the organisms captured were collected with a small trawl. Three stations with a water depth≤ 1 m were regularly sampled with a total number of 73 drops. Maximum abundance was for plaice in June (6 ind m^-2), for the shrimp in July-August (61 ind m^-2), and for sand goby in September (2 ind m^-2). Standing stocks (dry wt) were 0.2, 1.5 and 0.2 g m^-2 respectively. Production estimates were based on seasonal changes in size frequency and information on specific growth rates. The production rate was for plaice (0-group) 0.3 g m^-2 yr^-1, for the shrimp 1.5, and for sand goby 0.2 g m^-2 yr^-1. Reliable estimates of the absolute abundance can be derived from the mean catch per unit area only when the efficiency of the fishing gear is known. After 6 hauls with the trawl in the drop-net enclosure more than 85% of the shrimps were caught and after the fifteenth haul less than 1% were still left. The fishing efficiency of a push-net in relation to the drop-net was for the shrimp 50%, for plaice 35% and for sand goby 17%.     

Increasing the efficiency of variance component quantitative trait loci analysis by using reduced-rank identity-by-descent matrices

Recent technological development in genetics has made large-scale marker genotyping fast and practicable, facilitating studies for detection of QTL in large general pedigrees. We developed a method that speeds up restricted maximum-likelihood (REML) algorithms for QTL analysis by simplifying the inversion of the variance-covariance matrix of the trait vector. The method was tested in an experimental chicken pedigree including 767 phenotyped individuals and 14 genotyped markers on chicken chromosome 1. The computation time in a chromosome scan covering 475 cM was reduced by 43% when the analysis was based on linkage only and by 72% when linkage disequilibrium information was included. The relative advantage of using our method increases with pedigree size, marker density, and linkage disequilibrium, indicating even greater improvements in the future.