4,788 research outputs found

    Rad62 protein functionally and physically associates with the Smc5/Smc6 protein complex and is required for chromosome integrity and recombination repair in fission yeast

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    Smc5 and Smc6 proteins form a heterodimeric SMC (structural maintenance of chromosome) protein complex like SMC1-SMC3 cohesin and SMC2-SMC4 condensin, and they associate with non-SMC proteins Nse1 and Nse2 stably and Rad60 transiently. This multiprotein complex plays an essential role in maintaining chromosome integrity and repairing DNA double strand breaks (DSBs). This study characterizes a Schizosaccharomyces pombe mutant rad62-1, which is hypersensitive to methyl methanesulfonate (MMS) and synthetically lethal with rad2 (a feature of recombination mutants). rad62-1 is hypersensitive to UV and gamma rays, epistatic with rhp51, and defective in repair of DSBs. rad62 is essential for viability and genetically interacts with rad60, smc6, and brc1. Rad62 protein physically associates with the Smc5-6 complex. rad62-1 is synthetically lethal with mutations in the genes promoting recovery from stalled replication, such as rqh1, srs2, and mus81, and those involved in nucleotide excision repair like rad13 and rad16. These results suggest that Rad62, like Rad60, in conjunction with the Smc5-6 complex, plays an essential role in maintaining chromosome integrity and recovery from stalled replication by recombination

    RAD6-RAD18-RAD5-pathway-dependent tolerance to chronic low-dose ultraviolet light

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    In nature, organisms are exposed to chronic low- dose ultraviolet light ( CLUV) as opposed to the acute high doses common to laboratory experiments. Analysis of the cellular response to acute high-dose exposure has delineated the importance of direct DNA repair by the nucleotide excision repair pathway(1) and for checkpoint-induced cell cycle arrest in promoting cell survival(2). Here we examine the response of yeast cells to CLUV and identify a key role for the RAD6-RAD18-RAD5 error- free postreplication repair (RAD6 error-free PRR) pathway(3,4) in promoting cell growth and survival. We show that loss of the RAD6 error- free PRR pathway results in DNA-damage-checkpoint- induced G2 arrest in CLUV-exposed cells, whereas wild-type and nucleotide-excision-repair-deficient cells are largely unaffected. Cell cycle arrest in the absence of the RAD6 error- free PRR pathway was not caused by a repair defect or by the accumulation of ultraviolet-induced photoproducts. Notably, we observed increased replication protein A (RPA) and Rad52 - yellow fluorescent protein foci(5) in the CLUV- exposed rad18 Delta cells and demonstrated that Rad52- mediated homologous recombination is required for the viability of the rad18 Delta cells after release from CLUV- induced G2 arrest. These and other data presented suggest that, in response to environmental levels of ultraviolet exposure, the RAD6 error- free PRR pathway promotes replication of damaged templates without the generation of extensive single- stranded DNA regions. Thus, the error- free PRR pathway is specifically important during chronic low- dose ultraviolet exposure to prevent counter- productive DNA checkpoint activation and allow cells to proliferate normally

    A note on Dolby and Gull on radar time and the twin "paradox"

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    Recently a suggestion has been made that standard textbook representations of hypersurfaces of simultaneity for the travelling twin in the twin "paradox" are incorrect. This suggestion is false: the standard textbooks are in agreement with a proper understanding of the relativity of simultaneity.Comment: LaTeX, 3 pages, 2 figures. Update: added new section V and updated reference

    Specific recognition of a multiply phosphorylated motif in the DNA repair scaffold XRCC1 by the FHA domain of human PNK.

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    Short-patch repair of DNA single-strand breaks and gaps (SSB) is coordinated by XRCC1, a scaffold protein that recruits the DNA polymerase and DNA ligase required for filling and sealing the damaged strand. XRCC1 can also recruit end-processing enzymes, such as PNK (polynucleotide kinase 3'-phosphatase), Aprataxin and APLF (aprataxin/PNK-like factor), which ensure the availability of a free 3'-hydroxyl on one side of the gap, and a 5'-phosphate group on the other, for the polymerase and ligase reactions respectively. PNK binds to a phosphorylated segment of XRCC1 (between its two C-terminal BRCT domains) via its Forkhead-associated (FHA) domain. We show here, contrary to previous studies, that the FHA domain of PNK binds specifically, and with high affinity to a multiply phosphorylated motif in XRCC1 containing a pSer-pThr dipeptide, and forms a 2:1 PNK:XRCC1 complex. The high-resolution crystal structure of a PNK-FHA-XRCC1 phosphopeptide complex reveals the basis for this unusual bis-phosphopeptide recognition, which is probably a common feature of the known XRCC1-associating end-processing enzymes

    Techno-Economic Analysis and Feasibility of Industrial-Scale Activated Carbon Production from Agricultural Pea Waste Using Microwave-Assisted Pyrolysis: A Circular Economy Approach

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    This paper examines a novel approach to activated carbon (AC) production that uses pea waste (PW) and to what extent it is economically competitive with current production methods. Additionally, the outcome is to provide a detailed economic analysis to understand whether this process is viable. The focus of this production route and the economic analysis will be on a United Kingdom (UK) basis. The plant will be located within the north UK to minimise storage and transportation costs. It also has extensive links to other clusters of nearby industries that would produce from this process in air pollution control or wastewater treatments. The overall production process is detailed, and detailed equipment specifications, including the sizing of equipment and utility requirements, were also given. Material balance calculations are carried out to assess the performance and improve process design. An economic analysis is performed to study the potential of biomass-to-AC conversion costs and commercialisation viability. The project’s investment is about £100 million. The cost of the plant can be recovered from year 3 (mid) for the 20-year life of the plant. The Net Present Value (NPV) is based on cumulative cash flow. The NPV is calculated as GBP 4,476,137,297.79 for 2020, and the associated internal rate of return (IRR) and the return on investment (ROI) for the project are 55% and 52%, respectively

    Controlling Corporate Speech: Is Regulation Fair Disclosure Unconstitutional

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    We analyze whether Regulation Fair Disclosure, SEC Chairman Arthur Levitt\u27s crowning achievement, violates the First Amendment. Regulation FD requires that a company that discloses material non-public information to certain private audiences must also make that information public, subject to certain safe-harbors. The Regulation solely targets speech, acting either to compel it to a public audience or as a burden on private disclosure. Part I examines the reach of Regulation FD, the enforcement actions to date, and currently available empirical data. Part II provides an introduction to the interaction of the First Amendment and SEC regulations affecting speech. Part III broadens the analysis to include regulations compelling or burdening commercial and mixed commercial/non-commercial speech, and applies these lessons to Regulation FD in light of the clear trend towards greater protection of corporate speech. Finally, Part IV analyzes the SEC\u27s justifications for Regulation FD and evaluates how effectively they are achieved. We conclude that given the poor fit between the SEC\u27s means and ends, Regulation FD should not survive a constitutional challenge

    Industrial-Scale Activated Carbon Production from Agricultural Pea Waste: A Techno-Economic and Feasibility Study

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    This paper examines a novel approach to activated carbon (AC)production that uses pea waste (PW) and to what extent it iseconomically competitive with current production methods.Additionally, the outcome is to provide a detailed economicanalysis to understand whether this process is viable. The focusof this production route and the economic analysis will be on aUnited Kingdom (UK) basis. The plant will be located withinthe north UK to minimise storage and transportation costs. Italso has extensive links to other clusters of nearby industries thatwould produce from this process in air pollution control orwastewater treatments. The overall production process isdetailed, and detailed equipment specifications, including thesizing of equipment and utility requirements, were also given.Material balance calculations are carried out to assess theperformance and improve process design. An economicanalysis is performed to study the potential of biomass-to-ACconversion costs and commercialisation viability. The project’sinvestment is about £100 million. The cost of the plant can berecovered from year 3 (mid) for the 20-year life of the plant.The Net Present Value (NPV) is based on cumulative cash flow.The NPV is calculated as GBP 4,476,137,297.79 for 2020, andthe associated internal rate of return (IRR) and the return oninvestment (ROI) for the project are 55% and 52%, respectively

    POTENSI SUMBERDAYA LAHAN DI DAS BATANG BUNGO UNTUK PENGEMBANGAN SAYURAN (Land Resources Potency at Batang Bungo Watershed for Vegetables Development)

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    The aim of this research is to identify watershed land characteristic at Batang Bungo and to analyze land suitability for developing commodity vegetables that were dominantly utilized by the local farmer. It is found that there are 17 land units in Batang Bungo watershed, that used to be basic data to determine sample. The research showed that rubber was the main crop and green vegetables as intercropping plant. The green vegetables were planted dominantly pepper, string beans, and eggplant. These plants were cropped among young rubber plants. The land suitability analysis showed about 55790.2 ha (74,06%) of watershed wide were suitable, the rest was not suitable that by the caused by erosion hazard.   Keywords : Characteristic, erosion, watershed

    Social referencing and social appraisal: commentary on the Clément and Dukes (2016) and Walle et al. (2016) articles

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    We comment on two articles on social referencing and social appraisal. We agree with Walle, Reschke, and Knothe’s (2017) argument that at one level of analysis, social referencing and social appraisal are functionally equivalent: In both cases, another person’s emotional expression is observed and this expression informs the observer’s own emotional reactions and behavior. However, we also agree with Clément and Dukes’s (2017) view that (at another level of analysis), there is an important difference between social referencing and social appraisal. We also argue that they are likely to occur at different stages of emotion process
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