Design from Recycling

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Parallel genome-scale loss of function screens in 216 cancer cell lines for the identification of context-specific genetic dependencies

Using a genome-scale, lentivirally delivered shRNA library, we performed massively parallel pooled shRNA screens in 216 cancer cell lines to identify genes that are required for cell proliferation and/or viability. Cell line dependencies on 11,000 genes were interrogated by 5 shRNAs per gene. The proliferation effect of each shRNA in each cell line was assessed by transducing a population of 11M cells with one shRNA-virus per cell and determining the relative enrichment or depletion of each of the 54,000 shRNAs after 16 population doublings using Next Generation Sequencing. All the cell lines were screened using standardized conditions to best assess differential genetic dependencies across cell lines. When combined with genomic characterization of these cell lines, this dataset facilitates the linkage of genetic dependencies with specific cellular contexts (e.g., gene mutations or cell lineage). To enable such comparisons, we developed and provided a bioinformatics tool to identify linear and nonlinear correlations between these features

Evaluation of post-industrial and post-consumer polyolefin-based polymer waste streams for injection moulding

Do ponto de vista económico, os polímeros reciclados são uma matéria-prima interessante para o uso em moldação por injeção. Estes são mais baratos do que os materiais virgens e a sua utilização contribui para o desenvolvimento de produtos sustentáveis. O presente estudo foca-se em poliolefinas obtidas por essa via. Geralmente distinguem-se os fluxos de materiais secundários de acordo com a sua origem, como pós-industrial (PI, consistindo na moagem de resíduos de produção) ou pós-consumo (PC, consistindo em moagem de produtos usados de consumo). Dentro dos materiais pós-industriais pode ainda fazer-se a distinção adicional entre materiais relativamente puros, de elevada qualidade, de origens conhecidas, como os reciclados a partir de caixas de cerveja e equipamentos domésticos. Os pós-consumo são materiais contaminados (principalmente com outros polímeros) obtidos a partir de embalagens, que geralmente contêm quer polipropileno (PP), quer polietileno (PE) e são denominados misturas de poliolefinas (MPO). As complicações que surgem frequentemente com amostras de poliolefinas recicladas são a contaminação, a composição inconsistente ou desconhecida, alterações no fluxo e as reduzidas propriedades mecânicas. A última é muitas vezes atribuída à incompatibilidade entre o PP e o PE em fundido, o que leva à separação de fases e fragilização do produto. Neste estudo, são analisadas várias amostras de resíduos de poliolefinas disponíveis industrialmente, tanto PI como PC na sua origem e avaliadas quanto à sua composição, processamento e propriedades mecânicas.info:eu-repo/semantics/publishedVersio

Blending of recycled mixed polyolefins with recycled polypropylene : effect on physical and mechanical properties

Abstract. The similar densities of polyethylene (PE) and polypropylene (PP), complicate the separation for these materials in the mechanical recycling of post-consumer plastics. Therefore, recycled mixed polyolefins (rMPO) are widely available as recycled (r) polymer material. These blends are commonly cheaper, but also inferior in properties to relatively pure waste streams of rPP or rPE. In order to improve these materials, blends of rMPO were made with more expensive, relatively high quality rPP. This approach was purposefully ‘bottom up’, exploring how to upcycle the lower grade rMPO instead of downcycling higher grade rPP with a measure of added (cheaper) rMPO. Blends were made with two types of rMPO, the one a HDPE-PP blends from hard plastic waste and the other a LDPE-HDPE-PP blends, based mostly on foil materials. Each of these materials had one type of mechanical property in common with the high quality rPP, these being Young’s modulus and toughness respectively. Blends were made at different concentrations (0-50% in steps of 10%) and injection moulded into test samples. Density, MFI, mechanical strength, impact toughness and transition temperatures were experimentally determined for each blend. It was evaluated in how far the law-of-mixtures could apply to these blends and for those occurences where it did not, practical rules-of-thumb were composed