Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control

Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications

Passive, broadband and low-frequency suppression of laser amplitude noise to the shot-noise limit using hollow-core fibre

We use hollow-core fibre to preserve the spectrum and temporal profile of picosecond laser pulses in CBD to suppress 2.6 dB of amplitude noise at MHz noise frequencies, to within 0.01 dB of the shot-noise limit. We provide an enhanced version of the CBD scheme that concatenates circuits to suppress over multiple frequencies and over broad frequency ranges --- we perform a first demonstration that reduces total excess amplitude noise, between 2 - 6 MHz, by 85%. These demonstrations enable passive, broad-band, all-guided fibre laser technology operating at the shot-noise limit.Comment: 8 pages, 8 figure

Analysis of interfacial shrinkage stresses in patch repairs

This paper presents simple analytical expressions that predict the interfacial shrinkage stresses in a repair patch over time. Four repair materials (L2, L3, L4 and G1) were applied by spraying (gunite) to unpropped compression members of two highway structures, and their performance was monitored to approximately six months' age. The elastic moduli of all the repair materials, E rm , were greater than the elastic moduli of the substrate concrete, E sub . The mechanics of patch repair interaction with the substrate were established, and analytical models, based on an analogy of the bimetallic strip undergoing a drop in temperature, were developed. Basic properties of the repair material (elastic modulus, shrinkage and tensile creep) and substrate concrete (elastic modulus), and geometrical details of the repair patch, are required to analyse the interfacial stresses in the repair patch. Verification of the analytical procedures is based on the field data, and the results show a satisfactory correlation between the actual and predicted stress redistribution.</p

The Evolution of Successful Service-Learning Courses in the Computing Curriculum: From Infancy to innovation

The purpose of this paper is to relate the evolution of successful service-learning courses in a school of computer science and information systems spanning over a 20-year period. The authors share their experiences in developing technology-based service-learning courses for both majors and non-majors. Most recently, these courses have enabled undergraduate first-year students to be exposed to exciting technologies, such as robotics and mobile app development. The challenges, benefits, and lessons learned are discussed

Transient peak-strain matching partially recovers the age-impaired mechanoadaptive cortical bone response

Mechanoadaptation maintains bone mass and architecture; its failure underlies age-related decline in bone strength. It is unclear whether this is due to failure of osteocytes to sense strain, osteoblasts to form bone or insufficient mechanical stimulus. Mechanoadaptation can be restored to aged bone by surgical neurectomy, suggesting that changes in loading history can rescue mechanoadaptation. We use non-biased, whole-bone tibial analyses, along with characterisation of surface strains and ensuing mechanoadaptive responses in mice at a range of ages, to explore whether sufficient load magnitude can activate mechanoadaptation in aged bone. We find that younger mice adapt when imposed strains are lower than in mature and aged bone. Intriguingly, imposition of short-term, high magnitude loading effectively primes cortical but not trabecular bone of aged mice to respond. This response was regionally-matched to highest strains measured by digital image correlation and to osteocytic mechanoactivation. These data indicate that aged bone’s loading response can be partially recovered, non-invasively by transient, focal high strain regions. Our results indicate that old murine bone does respond to load when the loading is of sufficient magnitude, and bones’ age-related adaptation failure may be due to insufficient mechanical stimulus to trigger mechanoadaptation