Evolution of traceable radon emanation sources from MBq to few Bq.

In the framework of the EMPIR project traceRadon, stable atmospheres with low-level radon activity concentrations have to be produced for calibrating radon detectors designed to measure outdoor air activity concentrations. The traceable calibration of these detectors at very low activity concentrations is of special interest to the radiation protection, climate observation, and atmospheric research communities. Radiation protection networks (such as the EUropean Radiological Data Exchange Platform (EURDEP)) and atmospheric monitoring networks (such as the Integrated Carbon Observation System (ICOS)) need reliable and accurate radon activity concentration measurements for a variety of reasons, including: the identification of Radon Priority Areas (RPA); improving the sensitivity and reliability of radiological emergency early warning systems (Melintescu et al.

Development of Rn Emanation Sources with Integrated Quasi 2π Active Monitoring.

In this work, a novel approach for the standardization of low-level Rn emanation is presented. The technique is based on the integration of a Rn source, directly, with an α-particle detector, which allows the residual Rn to be continuously monitored. Preparation of the device entails thermal physical vapor deposition of RaCl directly onto the surface of a commercially available ion implanted Si-diode detector, resulting in a thin-layer geometry.

Ion implantation of Ra for a primary Rn emanation standard.

Laser resonance ionization at the RISIKO 30 kV mass separator has been used to produce isotopically and isobarically pure and well quantified Rn emanation standards. Based upon laser-spectroscopic preparation studies, ion implantation into aluminum and tungsten targets has been carried out, providing overall implantation efficiencies of 40% up to 60%. The absolute implanted activity of Ra was determined by the technique of defined solid-angle α-particle spectrometry, where excellent energy resolution was observed.

A new primary emanation standard for Radon-222.

New emanation sources for Rn-222 have been developed by electrodeposition of Ra-226 onto stainless-steel discs. With a high resolution of up to 20 keV FWHM in the Ra-226 peak at 4.87 MeV, defined solid-angle alpha-particle spectrometry is the method of choice to determine the deposited Ra-226 activity.

Development and validation of a ready to use cryo-EROD assay for the standardized screening of dioxins and dioxin-like compounds in foodstuffs.

Recent European regulations have indicated the need for new bioanalytical screening methods capable of monitoring dioxin and dioxin-like compounds in foodstuffs and environmental samples, cost-effectively and with a quicker turnaround. Cryo-cells of the hepatic H4IIE line preserved in 96-well plates were exposed to sample extracts prepared from various foodstuffs and analysed for their content of dioxins and dioxin-like compounds by means of the 7-Ethoxyresorufin-O-Deethylase (EROD)-assay in two laboratories. Assay data were compared between both laboratories and results from instrumental analysis used as a confirmatory method.

Comparative study of dioxin contamination from forest soil samples (BZE II) by mass spectrometry and EROD bioassay.

Dioxins and dioxin-like compounds can be analyzed by bioanalytical screening methods to evaluate their biotoxicity. In vitro bioassays, based on 7-ethoxyresorufin-O-deethylase (EROD) and the activity of cytochrome P450 1A1 and the aryl hydrogen receptor (AhR) pathway, are employed for the evaluation of bioanalytical equivalents (BEQ) of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from a wide variety of sample matrices. Here, we present the evaluation of 11 humic soil samples derived from forest stands across Germany and a comparison of the BEQ values against toxic equivalents (TEQ, PCDD/Fs+PCBs) derived by chemical analysis.

The fingerprints of dioxin-like bromocarbazoles and chlorocarbazoles in selected forest soils in Germany.

The occurrence of bromocarbazoles and chlorocarbazoles was studied in 86 forest soil samples from different regions in Germany. Carbazole, 3-chlorocarbazole, 3-bromocarbazole and 3,6-dibromocarbazole were qualitatively detected in the humic layer of 59 soil samples with bromocarbazoles reported here for the first time in soil. Furthermore, the halogenated carbazoles, PCDD/Fs and PCBs were detected in the humic and mineral soil horizons (0-5 cm and 5-10 cm) of a subset of 11 soil samples subjected to quantitative analysis.

Combined sequencing of mRNA and DNA from human embryonic stem cells.

Combined transcriptome and whole genome sequencing of the same ultra-low input sample down to single cells is a rapidly evolving approach for the analysis of rare cells. Besides stem cells, rare cells originating from tissues like tumor or biopsies, circulating tumor cells and cells from early embryonic development are under investigation. Herein we describe a universal method applicable for the analysis of minute amounts of sample material (150 to 200 cells) derived from sub-colony structures from human embryonic stem cells.

Combined ultra-low input mRNA and whole-genome sequencing of human embryonic stem cells.

Background: Next Generation Sequencing has proven to be an exceptionally powerful tool in the field of genomics and transcriptomics. With recent development it is nowadays possible to analyze ultra-low input sample material down to single cells. Nevertheless, investigating such sample material often limits the analysis to either the genome or transcriptome.

New technologies for DNA analysis--a review of the READNA Project.

The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received funding from the European Commission for 41/2 years. The objectives of the project revolved around technological developments in nucleic acid analysis. The project partners have discovered, created and developed a huge body of insights into nucleic acid analysis, ranging from improvements and implementation of current technologies to the most promising sequencing technologies that constitute a 3(rd) and 4(th) generation of sequencing methods with nanopores and in situ sequencing, respectively.

Creation and application of immortalized bait libraries for targeted enrichment and next-generation sequencing.

Since the introduction of next-generation sequencing, several techniques have been developed to selectively enrich and sequence specific parts of the genome at high coverage. These techniques include enzymatic methods employing molecular inversion probes, PCR based approaches, hybrid capture, and in-solution capture. In-solution capture employs RNA probes transcribed from a pool of DNA template oligos designed to match regions of interest to specifically bind and enrich genomic DNA fragments.

Targeted enrichment of genomic DNA regions for next-generation sequencing.

In this review, we discuss the latest targeted enrichment methods and aspects of their utilization along with second-generation sequencing for complex genome analysis. In doing so, we provide an overview of issues involved in detecting genetic variation, for which targeted enrichment has become a powerful tool. We explain how targeted enrichment for next-generation sequencing has made great progress in terms of methodology, ease of use and applicability, but emphasize the remaining challenges such as the lack of even coverage across targeted regions.

The application of massively parallel sequencing technologies in diagnostics.

Massively parallel sequencing (MPS) is rapidly evolving and is starting to be utilized by the clinical field as well as diagnostics. We describe major recent advances that have come about as a result of the application of MPS in the biomedical field and the first approaches in medical genetics that have made use of MPS. Without any doubt, MPS has proven to be a very powerful technique.

High-throughput Universal Probe Salmonella Serotyping (UPSS) by nanoPCR.

Salmonella enterica subsp. enterica serovar identification is of great importance with respect to outbreak monitoring and case verification. Therefore rapid, sensitive and cost efficient detection of Salmonella spp.

Cloning of mouse ojoplano, a reticular cytoplasmic protein expressed during embryonic development.

Ojoplano (Opo) is a morphogenetic gene playing an important role during embryogenesis in medaka. This report focuses on the identification and characterization of the mouse Opo gene. We examined Opo expression by whole-mount in situ hybridization and in situ hybridization on sagittal sections during mouse embryogenesis.

Proteomic shifts in embryonic stem cells with gene dose modifications suggest the presence of balancer proteins in protein regulatory networks.

Large numbers of protein expression changes are usually observed in mouse models for neurodegenerative diseases, even when only a single gene was mutated in each case. To study the effect of gene dose alterations on the cellular proteome, we carried out a proteomic investigation on murine embryonic stem cells that either overexpressed individual genes or displayed aneuploidy over a genomic region encompassing 14 genes. The number of variant proteins detected per cell line ranged between 70 and 110, and did not correlate with the number of modified genes.