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AimsIn addition to providing external quality assessment (EQA) schemes, United Kingdom National External Quality Assessment service (UK NEQAS) for Molecular Genetics also supports the education of laboratories. As an enhancement to the Molecular Pathology EQA scheme, a human cell-line reference sample, manufactured by Thermo Fisher Scientific (AcroMetrix), was provided for analysis. This contained many variants, present at frequencies between 1% and 17.9%.MethodsOne hundred and one laboratories submitted results, with a total of 2889 test results on 53 genes being reported. Known polymorphisms, 46/2889 (1.59%) results, were excluded. Variants detected in the seven most commonly reported (and clinically relevant) genes, KRAS, NRAS, BRAF, EGFR, PIK3CA, KIT and PDGFRA, are reported here, as these genes fall within the scope of UK NEQAS EQA schemes.ResultsNext generation sequencing (NGS) was the most commonly performed testing platform. There were between 5 and 27 validated variants in the seven genes reported here. Eight laboratories correctly reported all five NRAS variants, and two correctly reported all eight BRAF variants. The validated mean variant frequency was lower than that determined by participating laboratories, with single-gene testing methodologies showing less variation in estimated frequencies than NGS platforms. Laboratories were more likely to correctly identify clinically relevant variants.ConclusionsOver 100 laboratories took the opportunity to test the ‘educational reference sample’, showing a willingness to further validate their testing platforms. While it was encouraging to see that the most widely reported variants were those which should be included in routine testing panels, reporting of variants was potentially open to interpretation, thus clarity is still required on whether laboratories selectively reported variants, by either clinical relevance or variant frequency.

Phototoxicity potential was predicted for 88 substituted PAHs. The geometry of all PAHs was optimized and the molecular orbital energies were calculated using AM1 Hamiltonian. The highest occupied molecular orbital energy (E HOMO ) and the lowest unoccupied molecular orbital energy (E LUMO ) were used to calculate the energy gap (E HOMO −E LUMO ). The energy gap was used to predict phototoxicity for chloro-, bromo-, nitro-and methyl-substituted PAHs. Of the 88 compounds in the study, only nitro substituents on carbazole were predicted to induce phototoxicity of the nonphototoxic parent.

A new class of porous membrane, porous nanocrystalline silicon (pnc‐Si), offers a unique combination of nanoscale thickness (< 100 nm) and tunable pore sizes in the range of 5 to 100 nm. Pnc‐Si is ideally suited for small volume cell culture devices because the nanometer thinness and high permeability enable rapid diffusion of low abundance species with minimal loss. Two cell types can be cultured within tens of nanometers of one another, allowing cell‐cell communication and other microenvironment‐dependent co‐culture studies. We have developed an approach to create microwells on these suspended membranes using photopolymerized PEG. Cells grown within these microwells are spatially separated, but can readily communicate through the membrane with a feeder cell layer or with neighboring microwells due to PEG permeability. Additionally, pnc‐Si membranes are extraordinarily transparent to light, permitting their use in image‐based, high‐content screening assays. Sources of Funding: NIH and RIT.

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