796 research outputs found
Biogenesis and Turnover of Small RNAs The primary target of let-7 microRNA
Abstract The let-7 miRNA (microRNA) is an essential regulator of development from nematode worms to humans. Altered expression of let-7 results in larval arrest or lethality in Caenorhabditis elegans. Likewise, underor over-expression of let-7 in human cells can result in cellular overproliferation or halted cell division respectively. Thus the biogenesis of this critical miRNA is controlled at multiple levels. An unexpected mechanism for regulating the initial processing of let-7 was recently found to involve the let-7 miRNA itself. The mature let-7 miRNA along with its effector protein, Argonaute, were shown to bind to a site in the primary transcripts produced by the let-7 gene. This interaction enhances processing through a novel auto-regulatory feedback loop. This discovery highlights a new role for the miRNA complex in regulating miRNA biogenesis and enriches the classes of RNAs targeted by Argonaute
Status and specifications of a Project X front-end accelerator test facility at Fermilab
This paper describes the construction and operational status of an
accelerator test facility for Project X. The purpose of this facility is for
Project X component development activities that benefit from beam tests and any
development activities that require 325 MHz or 650 MHz RF power. It presently
includes an H- beam line, a 325 MHz superconducting cavity test facility, a 325
MHz (pulsed) RF power source, and a 650 MHz (CW) RF power source. The paper
also discusses some specific Project X components that will be tested in the
facility.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1
Apr 2011. New York, US
High level software for 4.8 GHz LHC Schottky system
The performance of the LHC depends critically on the accurate measurements of
the betatron tunes. The betatron tune values of each LHC beam may be measured
without excitation using a newly installed transverse Schottky monitor. A
high-level software package written in Java has been developed for the Schottky
system. The software allows end users to monitor and control the Schottky
system, and provides them with non-destructive and continuous bunch-by-bunch
measurements for the tunes, momentum spreads, chromaticities and emittances of
the LHC beams. It has been tested with both proton and lead ion beams at the
LHC with very successful results.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1
Apr 2011. New York, US
Facing up to bias in healthcare: The influence of familiarity appearance on hiring decisions
Associations between facial appearance and hiring decisions are well-documented within job literature as a source of decision misjudgment with economic and human costs. Notwithstanding, this aspect is yet to be investigated in healthcare. We collected 90 pictures of new-graduates nurses faces to be judged on different facial appearance-based traits by an independent sample. Six months after graduation, the same new-graduates were interviewed about their job situation. Binomial logistic regression was conducted to examine whether facial appearance ratings would predict the probability to be hired as nurse. Results showed that applicants with a face conveying a feeling of familiarity were more likely to be hired. Considering that people might be inclined to these biases during societal crises and the exceptional need to quickly recruit health professionals during COVID-19 pandemic, our study recommends special attention to prevent the influence of facial appearance-based evaluations not reflecting real skills to limit potentially adverse consequences
Aspects of Cooling at the TRIP Facility
The TriP facility at KVI is dedicated to provide short lived radioactive
isotopes at low kinetic energies to users. It comprised different cooling
schemes for a variety of energy ranges, from GeV down to the neV scale. The
isotopes are produced using beam of the AGOR cyclotron at KVI. They are
separated from the primary beam by a magnetic separator. A crucial part of such
a facility is the ability to stop and extract isotopes into a low energy
beamline which guides them to the experiment. In particular we are
investigating stopping in matter and buffer gases. After the extraction the
isotopes can be stored in neutral atoms or ion traps for experiments. Our
research includes precision studies of nuclear -decay through
- momentum correlations as well as searches for permanent electric
dipole moments in heavy atomic systems like radium. Such experiments offer a
large potential for discovering new physics.Comment: COOL05 Workshop, Galena, Il, USA, 18-23. Sept. 2005, 5 pages, 3
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The Period protein homolog LIN-42 negatively regulates microRNA biogenesis in C. elegans
AbstractMicroRNAs (miRNAs) are small RNAs that post-transcriptionally regulate gene expression in many multicellular organisms. They are encoded in the genome and transcribed into primary (pri-) miRNAs before two processing steps that ultimately produce the mature miRNA. In order to generate the appropriate amount of a particular miRNA in the correct location at the correct time, proper regulation of miRNA biogenesis is essential. Here we identify the Period protein homolog LIN-42 as a new regulator of miRNA biogenesis in Caenorhabditis elegans. We mapped a spontaneous suppressor of the normally lethal let-7(n2853) allele to the lin-42 gene. Mutations in this allele (ap201) or a second lin-42 allele (n1089) caused increased mature let-7 miRNA levels at most time points when mature let-7 miRNA is normally expressed. Levels of pri-let-7 and a let-7 transcriptional reporter were also increased in lin-42(n1089) worms. These results indicate that LIN-42 normally represses pri-let-7 transcription and thus the accumulation of let-7 miRNA. This inhibition is not specific to let-7, as pri- and mature levels of lin-4 and miR-35 were also increased in lin-42 mutants. Furthermore, small RNA-seq analysis showed widespread increases in the levels of mature miRNAs in lin-42 mutants. Thus, we propose that the period protein homolog LIN-42 is a global regulator of miRNA biogenesis
Regulation of lin-4 miRNA expression, organismal growth and development by a conserved RNA binding protein in C. elegans
AbstractTranscription and multiple processing steps are required to produce specific 22 nucleotide microRNAs (miRNAs) that can regulate the expression of target genes. In C. elegans, mature lin-4 miRNA accumulates at the end of the first larval stage to repress its direct targets lin-14 and lin-28, allowing the progression of several somatic cell types to later larval fates. In this study, we characterized the expression of endogenous lin-4 and found that temporally regulated independent transcripts, but not constitutive lin-4 containing RNAs derived from an overlapping gene, are processed to mature lin-4 miRNA. Through an RNAi screen, we identified a conserved RNA binding protein gene rbm-28 (R05H10.2), homologous to the human RBM28 and yeast Nop4p proteins, that is important for lin-4 expression in C. elegans. We also demonstrate that rbm-28 genetically interacts with the lin-4 developmental timing pathway and uncover a previously unrecognized role for lin-14 and lin-28 in coordinating organismal growth
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