2,697 research outputs found
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A nucleotide resolution map of Top2-linked DNA breaks in the yeast and human genome
DNA topoisomerases are required to resolve DNA topological stress. Despite this essential role, abortive topoisomerase activity generates aberrant protein-linked DNA breaks, jeopardising genome stability. Here, to understand the genomic distribution and mechanisms underpinning topoisomerase-induced DNA breaks, we map Top2 DNA cleavage with strand-specific nucleotide resolution across the S. cerevisiae and human genomes—and use the meiotic Spo11 protein to validate the broad applicability of this method to explore the role of diverse topoisomerase family members. Our data characterises Mre11-dependent repair in yeast and defines two strikingly different fractions of Top2 activity in humans: tightly localised CTCF-proximal, and broadly distributed transcription-proximal, the latter correlated with gene length and expression. Moreover, single nucleotide accuracy reveals the influence primary DNA sequence has upon Top2 cleavage—distinguishing sites likely to form canonical DNA double-strand breaks (DSBs) from those predisposed to form strand-biased DNA single-strand breaks (SSBs) induced by etoposide (VP16) in vivo
A Taxonomy of Fabric Integrated Thermal Energy Storage: A review of storage types and building locations
Thermal energy storage incorporated into the fabric of buildings could provide the opportunity to significantly improve the use of energy from renewable sources and take maximum advantage of off-peak electricity tariffs. If this kind of thermal storage is integrated into the structure of the building itself, the internal space of the building is not compromised and may be more cost-effective.
In this paper, the authors present a taxonomy of currently available fabric-integrated thermal energy storage solutions based on a review of existing literature. The aim of this study is to map the range of extant design solutions for fabric-integrated thermal storage in buildings and detect any omissions.
The taxonomy presented in this paper takes into consideration the interaction between the storage of thermal energy and the thermal zones of buildings, the methods and medium used to store thermal energy, and the storage temperature. Also considered here are the different architectural integration options, which the authors present through a catalogue of possible thermal energy storage locations.
This paper also argues that an active storage system provides a means for energy systems in buildings to actively participate in future energy networks, which may require active load management to accommodate a high proportion of renewable technologies. Active storage allows the charge and discharge of the thermal energy stored within buildings when the energy is available and/or economically valuable. This kind of active participation is not possible with passive storage techniques
A Taxonomy of Fabric Integrated Thermal Energy Storage: A review of storage types and building locations
Thermal energy storage incorporated into the fabric of buildings provides the opportunity to significantly reduce the energy load of those buildings, improve the use of energy from renewable sources and take maximum advantage of off-peak electricity tariffs. If this kind of thermal storage is integrated into the structure of the building itself, the internal space of the building is not compromised.
In this paper, the authors present a taxonomy of currently available fabric-integrated thermal energy storage solutions based on a review of existing literature. The aim of this study is to map the range of extant design solutions for fabric-integrated thermal storage in buildings and detect any omissions in this range of designs.
The taxonomy presented in this paper takes into consideration the interaction between the storage of thermal energy and the thermal zones of buildings, the methods and medium used to store thermal energy, and the storage temperature. Also considered here are the different architectural integration options, which the authors present through a catalogue of possible thermal energy storage locations.
This paper argues that an active storage system provides a link for active participation in the energy network. Active storage allows the charge and discharge of the thermal energy stored within such buildings when the energy is available and/or economically valuable. This kind of active participation is not possible with passive storage techniques
Public Awareness of Medical Imaging as a Source of Ionizing Radiation Exposure
Background. Biological effects of exposure to ionizing radiation (IR) are well known. Literature suggests most patients and physicians lack proficient understanding of risks associated with ionizing radiation. Our study goals were to: assess the extent to which productive, informed conversations regarding ionizing radiation are occurring between patients and providers; characterize public awareness of medical imaging procedures as sources of IR exposure; and investigate best practices in patientprovider communications.
Methods. We developed and administered a 17-question survey to 303 adults at five locations across Chittenden County, Vermont, over a 6-week period in fall 2016. Descriptive and statistical analyses were conducted using SPSS.
Results. The three age groups of respondents had different knowledge levels about ionizing radiation (p
Conclusions/Recommendations. 1. A standard oral presentation for pre-imaging patient-provider communication, along with a written handout, be developed; 2. A section of the electronic medical record (also accessible through the patient portal) containing IR exposure be created for patients and physicians to track individuals\u27 information.https://scholarworks.uvm.edu/comphp_gallery/1249/thumbnail.jp
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Neural emotion regulation circuitry underlying anxiolytic effects of perceived control over pain.
Anxiolytic effects of perceived control have been observed across species. In humans, neuroimaging studies have suggested that perceived control and cognitive reappraisal reduce negative affect through similar mechanisms. An important limitation of extant neuroimaging studies of perceived control in terms of directly testing this hypothesis, however, is the use of within-subject designs, which confound participants' affective response to controllable and uncontrollable stress. To compare neural and affective responses when participants were exposed to either uncontrollable or controllable stress, two groups of participants received an identical series of stressors (thermal pain stimuli). One group ("controllable") was led to believe they had behavioral control over the pain stimuli, whereas another ("uncontrollable") believed they had no control. Controllable pain was associated with decreased state anxiety, decreased activation in amygdala, and increased activation in nucleus accumbens. In participants who perceived control over the pain, reduced state anxiety was associated with increased functional connectivity between each of these regions and ventral lateral/ventral medial pFC. The location of pFC findings is consistent with regions found to be critical for the anxiolytic effects of perceived control in rodents. Furthermore, interactions observed between pFC and both amygdala and nucleus accumbens are remarkably similar to neural mechanisms of emotion regulation through reappraisal in humans. These results suggest that perceived control reduces negative affect through a general mechanism involved in the cognitive regulation of emotion
A new population of recently quenched elliptical galaxies in the SDSS
We use the Sloan Digital Sky Survey to investigate the properties of massive
elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue
optical colors. Through careful inspection, we distinguish elliptical from
non-elliptical morphologies among a large sample of similarly blue galaxies
with high central light concentrations (c_r\geq2.6). These blue ellipticals
comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between
10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra
diagnostics, we identify a unique subset of 172 non-star-forming ellipticals
with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar
ages. These recently quenched ellipticals (RQEs) have a number density of
2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above
2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the
expected quiescent growth at late cosmic time assuming this phase lasts 0.5
Gyr. RQEs have properties that are consistent with a recent merger origin
(i.e., they are strong `first-generation' elliptical candidates), yet few
involved a starburst strong enough to produce an E+A signature. The preferred
environment of RQEs (90 per cent reside at the centers of < 3\times
10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale'
predicted for maximally efficient spiral merging onto their halo center and
rules out satellite-specific quenching processes. The high incidence of Seyfert
and LINER activity in RQEs and their plausible descendents may heat the
atmospheres of small host halos sufficiently to maintain quenching.Comment: 26 pages, 9 figures. Revised version; accepted for publication in
MNRA
Single leg stance control in individuals with symptomatic gluteal tendinopathy
Background Lateral hip pain during single leg loading, and hip abductor muscle weakness, are associated with gluteal tendinopathy, but it has not been shown how or whether kinematics in single leg stance differ in those with gluteal tendinopathy. Purpose To compare kinematics in preparation for, and during, single leg stance between individuals with and without gluteal tendinopathy, and the effect of hip abductor muscle strength on kinematics. Methods Twenty individuals with gluteal tendinopathy and 20 age-matched pain-free controls underwent three-dimensional kinematic analysis of single leg stance and maximum isometric hip abductor strength testing. Maximum values of hip adduction, pelvic obliquity (contralateral pelvis rise/drop), lateral pelvic translation (ipsilateral/contralateral shift) and ipsilateral trunk lean during preparation for leg lift and average values in steady single leg stance, were compared between groups using an analysis of covariance, with and without anthropometric characteristics and strength as covariates. Results Individuals with gluteal tendinopathy demonstrated greater hip adduction (standardized mean difference (SMD)\ua0=\ua00.70, P\ua0=\ua00.04) and ipsilateral pelvic shift (SMD\ua0=\ua01.1, P\ua0=\ua00.002) in preparation for leg lift, and greater hip adduction (SMD\ua0=\ua01.2, P\ua0=\ua00.002) and less contralateral pelvic rise (SMD\ua0=\ua00.86, P\ua0=\ua00.02) in steady single leg stance than controls. When including strength as a covariate, only between-group differences in lateral pelvic shift persisted (SMD\ua0=\ua01.7, P\ua0=\ua00.01). Conclusion Individuals with gluteal tendinopathy use different frontal plane kinematics of the hip and pelvis during single leg stance than pain-free controls. This finding is not influenced by pelvic dimension or the potentially modifiable factor of body mass index, but is by hip abductor muscle weakness
Building a Plastics Fabrication Laboratory on the ISS: FabLab, MANTIS, Refabricator, CRISSP, ERASMUS, and MAMBA
The objective of NASA's In Space Manufacturing program is to develop manufacturing technologies and processes necessary to provide "on-demand, sustainable operations for exploration missions." Using the ISS as a test bed, in 2014, NASA installed and successfully tested a 3D printer for in-space operations, demonstrating the 3D printing process as well as sending digital files for printing from earth to the printer. The success of this technology demonstration has shown that on-orbit manufacturing technologies can be used to limit the earth reliance for cis-lunar missions. Because of this success, numerous opportunities have been provided by NASA to further in-space manufacturing by focusing on the development of highly autonomous manufacturing systems, recycling technologies, and robotics with the ultimate goal of building a fabrication laboratory now within reach. From technologies developed for ISS activities and demonstration missions, Tethers Unlimited, Inc. (TUI) is building a Plastics Manufacturing Laboratory capable of fabricating parts on-demand and as-needed while recycling waste plastics with minimal human interaction required. Parts will be manufactured through additive manufacturing. Precision machining will ensure manufactured parts are in tolerance with the end-use requirements. Recycling waste plastics will enable both waste from the crew and waste from processing to be re-processed into something new. In addition, these manufacturing and recycling technologies are supported by part verification/validation technique and robotic servicing, minimizing human interaction with the system and eventually enabling unmanned off-world manufacturing
Assessing Domestic Heat Storage Requirements for Energy Flexibility Over Varying Timescales
This paper explores the feasibility of storing heat in an encapsulated store to support thermal load shifting over three timescales: diurnal, weekly and seasonal. A building simulation tool was used to calculate the space heating and hot water demands for four common UK housing types and a range of operating conditions. A custom sizing methodology calculated the capacities of storage required to fully meet the heat demands over the three timescales. Corresponding storage volumes were calculated for a range of heat storage materials deemed suitable for storing heat within a dwelling, either in a tank or as an integral part of the building fabric: hot water, concrete, high-temperature magnetite blocks, and a phase change material. The results indicate that with low temperature heat storage, domestic load shifting is feasible over a few days. Beyond this timescale, the very large storage volumes required make integration in dwellings problematic. Supporting load shifting over 1–2 weeks is feasible with high temperature storage. Retention of heat over periods longer than this is challenging, even with significant levels of insulation. Seasonal storage of heat in an encapsulated store appeared impractical in all cases modelled due to the volume of material required
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