5 research outputs found

    Different forms of TFIIH for transcription and DNA repair: Holo-TFIIH and a nucleotide excision repairosome

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    AbstractYeast TFIIH that is active in transcription can be dissociated into three components: a 5-subunit core, the SSL2 gene product, and a complex of 47 kDa, 45 kDa, and 33 kDa polypeptides that possesses protein kinase activity directed towards the C-terminal repeat domain of RNA polymerase II. These three components can reconstitute fully functional TFIIH, and all three are required for transcription in vitro. By contrast, TFIIH that is highly active in nucleotide excision repair (NER) lacks the kinase complex and instead contains the products of all other genes known to be required for NER in yeast: RAD1, RAD2, RAD4, RAD10, and RAD14. This repairosome is not active in reconstituted transcription in vitro and is significantly more active than any of the constituent polypeptides in correcting defective repair in extracts from strains mutated in NER genes

    Three-dimensional graphene biointerface with extremely high sensitivity to single cancer cell monitoring

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    We developed a three-dimensional biointerface of graphene-based electrical impedance sensor for metastatic cancer diagnosis at single-cell resolution. Compared with traditional impedance sensor with two-dimensional interface, the graphene biointerface mimiced the topography and somatotype features of cancer cells, achieving more comprehensive and thorough single cell signals in the three-dimensional space. At the nodes of physiological behavior change of single cell, namely cell capture, adhesion, migration and proliferation, the collected electrical signals from graphene biointerface were about two times stronger than those from the two-dimensional gold interface due to the substantial increase in contact area and significant improvement of topographical interaction between cells and graphene electrode. Simultaneous CCD recording and electrical signal extraction from the entrapped single cell on the graphene biointerface enabled to investigate multidimensional cell-electrode interactions and predict cancerous stage and pathology

    The impacts of lithium and silicon coating on the W source in EAST

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    Application of lithium (Li) or silicon (Si) wall coating in the Experimental Advanced Superconducting Tokamak (EAST) has proven to be an effective method to reduce fuel recycling and control impurity level, and also to improve the plasma performance. In 2014, the upper graphite divertor in EAST was upgraded into a full tungsten (W) one with ITER-like actively water-cooled monoblock structure. Note that there is still large surface area of first wall covered by graphite tiles, including the lower divertor, NBI shine through armor, the outboard guard limiters, etc. In 2016 spring campaign, both Li and Si were used to coat the first wall in experimental sequences that lasted more than one month each. The spectroscopic observation reveals that compared to Si coating, Li coating more effectively suppresses in-vessel impurities, thus mitigating the W source in upper divertor. This is further quantified by a reduction of the effective W sputtering yield calculation. Carbon (C) impurity is suggested as the main impurity governing W sputtering, and correlates inverselywith the wall coating evolution during both one-day experiments and the whole campaign. The impurity concentration increases measurably after every vacuum vessel exposure to air during the campaign; substantial time is required for impurities to return to baseline levels. Real-time Li aerosol injection into the upper divertor effectively reduces the W sputtering by cooling the edge plasma and dissipating the power flux to divertor target, consequently providing an active tool for radiation divertor control. Keywords: Lithium and silicon coating, Tungsten erosion, Impurity concentration, Spectroscopic diagnosi
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