34 research outputs found

    Chd1 co-localizes with early transcription elongation factors independently of H3K36 methylation and releases stalled RNA polymerase II at introns

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    BACKGROUND: Chromatin consists of ordered nucleosomal arrays that are controlled by highly conserved adenosine triphosphate (ATP)-dependent chromatin remodeling complexes. One such remodeler, chromodomain helicase DNA binding protein 1 (Chd1), is believed to play an integral role in nucleosomal organization, as the loss of Chd1 is known to disrupt chromatin. However, the specificity and basis for the functional and physical localization of Chd1 on chromatin remains largely unknown. RESULTS: Using genome-wide approaches, we found that the loss of Chd1 significantly disrupted nucleosome arrays within the gene bodies of highly transcribed genes. We also found that Chd1 is physically recruited to gene bodies, and that its occupancy specifically corresponds to that of the early elongating form of RNA polymerase, RNAPII Ser 5-P. Conversely, RNAPII Ser 5-P occupancy was affected by the loss of Chd1, suggesting that Chd1 is associated with early transcription elongation. Surprisingly, the occupancy of RNAPII Ser 5-P was affected by the loss of Chd1 specifically at intron-containing genes. Nucleosome turnover was also affected at these sites in the absence of Chd1. We also found that deletion of the histone methyltransferase for H3K36 (SET2) did not affect either Chd1 occupancy or nucleosome organization genome-wide. CONCLUSIONS: Chd1 is specifically recruited onto the gene bodies of highly transcribed genes in an elongation-dependent but H3K36me3-independent manner. Chd1 co-localizes with the early elongating form of RNA polymerase, and affects the occupancy of RNAPII only at genes containing introns, suggesting a role in relieving splicing-related pausing of RNAPII. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1756-8935-7-32) contains supplementary material, which is available to authorized users

    Short course daily prednisolone therapy during an upper respiratory tract infection in children with relapsing steroid-sensitive nephrotic syndrome (PREDNOS 2):protocol for a randomised controlled trial

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    BACKGROUND: Relapses of childhood steroid-sensitive nephrotic syndrome (SSNS) are treated with a 4- to 8-week course of high-dose oral prednisolone, which may be associated with significant adverse effects. There is a clear association between upper respiratory tract infection (URTI) and relapse development. Previous studies in developing nations have suggested that introducing a 5- to 7-day course of daily prednisolone during an URTI may prevent a relapse developing and the need for a treatment course of high-dose prednisolone. The aim of PREDNOS 2 is to evaluate the effectiveness of a 6-day course of daily prednisolone therapy during an URTI in reducing the development of a subsequent relapse in a developed nation.METHODS/DESIGN: The subjects will be 300 children with relapsing SSNS (≥2 relapses in preceding year), who will be randomised to receive either a 6-day course of daily prednisolone or no change to their current therapy (with the use of placebo to double blind) each time they develop an URTI over 12 months. A strict definition for URTI will be used. Subjects will be reviewed at 3, 6, 9 and 12 months to capture data regarding relapse history, ongoing therapy and adverse effect profile, including behavioural problems and quality of life. A formal health economic analysis will also be performed. The primary end point of the study will be the incidence of URTI-related relapse (3 days of Albustix +++) following the first infection during the 12-month follow-up period. DNA and RNA samples will be collected to identify a potential genetic cause for the disease. Subjects will be recruited from over 100 UK centres with the assistance of the Medicines for Children Research Network. PREDNOS 2 is funded by the National Institute for Health Research Health Technology Assessment Programme (11/129/261).DISCUSSION: We propose that PREDNOS 2 will be a pivotal study that will inform the future standard of care for children with SSNS. If it is possible to reduce the disease relapse rate effectively and safely, this will reduce the morbidity and cost associated with drug treatment, notwithstanding hospital admission and parental absence from employment.TRIAL REGISTRATION: Current Controlled Trials (ISRCTN10900733).</p

    Impact of dual nano-enhanced phase change materials on mitigating thermal runaway in lithium-ion battery cell

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    Thermal management remains a pivotal challenge in enhancing the safety and efficiency of lithium-ion batteries, especially under conditions prone to thermal runaway. This study investigates the performance of dual nano-enhanced phase change materials (NEPCM) in moderating extreme thermal events in battery cells. By integrating nanoparticles, specifically alumina and single-walled carbon nanotubes (SWCNT), into phase change materials (PCM), the study explores modifications in thermal behavior and phase change dynamics within a cylindrical battery enclosure. The research focuses on comparing the thermal performance of pure PCM and NEPCM, using two types of nanoparticles dispersed within the PCM matrix at various volume fractions. The findings indicate that NEPCM significantly improves heat transfer rates and accelerates the melting process. Specifically, NEPCM with 6 % SWCNT increases the melting temperature distribution by up to 15.27 % compared to pure PCM setups and enhances the liquid fraction by up to 66.54 % under similar conditions. The inclusion of SWCNT demonstrates a superior enhancement in thermal conductivity compared to alumina, leading to more effective heat absorption and dissipation. Liquid fraction analysis confirms that NEPCM configurations facilitate quicker and more uniform thermal behaviors, especially near the heat source. PCM1, positioned adjacent to the battery, exhibits an immediate increase in temperature and melting rate, significantly outperforming PCM2 in thermal regulation. This study underscores the potential of dual nano-enhanced PCM in improving the thermal management of lithium-ion batteries, particularly in scenarios at risk of thermal runaway. By optimizing the PCM formulation with nanoparticles, a robust solution is presented to control temperature spikes and improve battery safety and durability in challenging operational environments
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