1,287 research outputs found
Mini-mast CSI testbed user's guide
The Mini-Mast testbed is a 20 m generic truss highly representative of future deployable trusses for space applications. It is fully instrumented for system identification and active vibrations control experiments and is used as a ground testbed at NASA-Langley. The facility has actuators and feedback sensors linked via fiber optic cables to the Advanced Real Time Simulation (ARTS) system, where user defined control laws are incorporated into generic controls software. The object of the facility is to conduct comprehensive active vibration control experiments on a dynamically realistic large space structure. A primary goal is to understand the practical effects of simplifying theoretical assumptions. This User's Guide describes the hardware and its primary components, the dynamic characteristics of the test article, the control law implementation process, and the necessary safeguards employed to protect the test article. Suggestions for a strawman controls experiment are also included
Inorganic Polyphosphates Are Important for Cell Survival and Motility of Human Skin Keratinocytes and Play a Role in Wound Healing
Inorganic polyphosphate (polyP) is a simple ancient polymer of linear chains of orthophosphate residues linked by high energy phospho-anhydride bonds ubiquitously found in all organisms. Despite its structural simplicity, it plays diverse functional roles. polyP is involved in myriad of processes including serving as microbial phosphagens, buffer against alkalis, Ca2+ storage, metal-chelating agents, pathogen virulence, cell viability and proliferation, structural component and chemical chaperones, and in the microbial stress response. In mammalian cells, polyP has been implicated in blood coagulation, inflammation, bone differentiation, cell bioenergetics, signal transduction, Ca2+-signaling, neuronal excitability, as a protein-stabilizing scaffold, and in wound healing, among others. This chapter will discuss (1) polyP metabolism and roles of polyP in prokaryotic and eukaryotic cells, (2) the contribution of polyP to survival, cell proliferation, and motility involved in wound healing in human skin keratinocytes, (3) the use of polyP-containing platelet-rich plasma (PRP) to promote wound healing in acute and chronic wounds, including burns, and (4) the use of polyP-containing PRP in excisional wound models to promote faster healing. While polyP shows promise as a therapeutic agent to accelerate healing for acute and chronic wounds, the molecular mechanisms as a potent modulator of the wound healing process remain to be elucidated
Understanding symptoms in RYR1-Related Myopathies: A mixed-methods analysis based on participants' experience
Background: In rare diseases such as ryanodine receptor 1-related myopathies (RYR1-RM), health-related quality of life (HRQoL) measures are critically important so clinicians and researchers can better understand what symptoms are most important to participants, with the ultimate goal of finding tangible solutions for them. Objectives: The main objective of this study was to characterize symptoms in individuals with RYR1-RM to inform future research. A secondary objective of this study was to analyze positive and negative sentiments regarding symptoms and treatment effects post N-acetylcysteine (NAC) administration in individuals with RYR1-RM. Methods: The study used a mixed-methods design applying methodological triangulation. Qualitative data were collected via semi-structured interviews at three visits to characterize symptoms in individuals with RYR1-RM and to analyze treatment effects. Qualitative data were then transformed into quantitative results to measure the frequency with which each symptom was mentioned by participants. Results: A total of 12 symptoms were identified as areas of interest to participants with RYR1-RM, highlighting fatigue and weakness as key symptoms. Data transformation categorized more than 1000 citations, reporting a greater number of positive comments for post-intervention interviews than for baseline and pre-intervention visits and that NAC group participants stated more positive comments regarding treatment effect than did the placebo group. Conclusions: We present a comprehensive characterization of symptoms in RYR1-RM and how those symptoms influence HRQoL. Furthermore, the introduction of mixed methods may be a valuable way to better understand patient-centered data in rare diseases to support affected individuals in coping with their symptoms
Mentoring relationships in sport from the protégé’s perspective
This study explored mentoring relationships in sport from the perspective of the protégé. The project was guided by contemporary mentoring theories as framed by Kram's Mentor Role Theory (Kram, 1985). A convenience sample of 230 volleyball coaches was recruited for this study. Data were collected using the Coaches Mentor Role Instrument (CMRI) (Schempp, McCullick, Berger, White, & Elliott, 2014). Quantitative methods indicated significant mentor role differences based on continuation of relationship, participation in a formal mentor programme, and gender. The participants perceived their mentors as most effective in the roles of acceptor, friend, role model and challenger
Main-Belt Comet P/2012 T1 (PANSTARRS)
We present initial results from observations and numerical analyses aimed at
characterizing main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring
observations were made between October 2012 and February 2013 using the
University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay
Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell
Observatory, and the Southern Astrophysical Research (SOAR) telescope. The
object's intrinsic brightness approximately doubles from the time of its
discovery in early October until mid-November and then decreases by ~60%
between late December and early February, similar to photometric behavior
exhibited by several other main-belt comets and unlike that exhibited by
disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic
searches for CN emission as well as absorption at 0.7 microns that could
indicate the presence of hydrated minerals, finding an upper limit CN
production rate of QCN<1.5x10^23 mol/s, from which we infer a water production
rate of QH2O<5x10^25 mol/s, and no evidence of the presence of hydrated
minerals. Numerical simulations indicate that P/2012 T1 is largely dynamically
stable for >100 Myr and is unlikely to be a recently implanted interloper from
the outer solar system, while a search for potential asteroid family
associations reveal that it is dynamically linked to the ~155 Myr-old Lixiaohua
asteroid family.Comment: 15 pages, 4 figures, accepted for publication in ApJ Letter
Mixed methods analysis of Health-Related Quality of Life in ambulant individuals affected with RYR1-related myopathies pre-post-N-acetylcysteine therapy
Purpose: To characterize Health-Related Quality of Life (HRQoL) in ambulant individuals with RYR1-RM and to determine if a qualitative PRO tool (subjective self-assessment) complements PROMIS and Neuro-QoL scales to detect changes in HRQoL in ambulant individuals with RYR1-RM post N-acetylcysteine (NAC) treatment. Methods: The study used a mixed methods research (MMR) design applying methodological triangulation. Qualitative data were collected via semi-structured interviews using open-ended questions. Quantitative data were gathered through PROMIS and Neuro-QoL instruments. Additionally, qualitative data were transformed into quantitative data for subjective self-assessment and frequency analyses. Results: Qualitative results identified five domains and 33 subdomains as areas of interest. The most valuable were the importance of social impacts, the development of several coping strategies, both physical and psychological, and the identification of fatigue and weakness as key symptoms. Data transformation then categorized more than 3100 citations on frequency analyses, globally and by domain, visit, and participant. Regarding quantitative results, there was no clear evidence that any of the three PRO tools captured positive changes as a result of NAC treatment. Conclusion: Qualitative results showed a comprehensive characterization of HRQoL in this population based on a symptom/patient-centered approach. These findings will inform future studies. Furthermore, given the similar findings across our multiple methods and endpoints, the introduction of MMR may be a valuable, complementary approach to clinical trials. MMR may be especially useful to incorporate in order to address and follow the FDA's guidance and prioritization on the inclusion of affected individuals' perspectives in clinical trials
Restricted Expression of G86R Cu/Zn Superoxide Dismutase in Astrocytes Results in Astrocytosis But Does Not Cause Motoneuron Degeneration
Evidence garnered from both human autopsy studies and genetic animal models has suggested a potential role for astrocytes in the pathogenesis of amyotrophic lateral sclerosis (ALS). Currently, mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1) represent the only known cause of motoneuron loss in the disease, producing 21q linked familial ALS (FALS). To determine whether astrocytic dysfunction has a primary role in familial ALS, we have generated multiple lines of transgenic mice expressing G86R mutant SOD1 restricted to astrocytes. In GFAP-m SOD1 mice, astrocytes exhibit significant hypertrophy and increased GFAP reactivity as the animals mature. However, GFAP-mutant SOD1 transgenic mice develop normally and do not experience spontaneous motor deficits with increasing age. Histological examination of spinal cord in aged GFAP-mSOD1 mice reveals normal motoneuron and microglial morphology. These results indicate that 21q linked FALS is not a primary disorder of astrocytes, and that expression of mutant SOD1 restricted to astrocytes is not sufficient to cause motoneuron degeneratio
Opposing brain differences in 16p11.2 deletion and duplication carriers
Deletions and duplications of the recurrent ∼600 kb chromosomal BP4–BP5 region of 16p11.2 are associated with a broad variety of neurodevelopmental outcomes including autism spectrum disorder. A clue to the pathogenesis of the copy number variant (CNV)'s effect on the brain is that the deletion is associated with a head size increase, whereas the duplication is associated with a decrease. Here we analyzed brain structure in a clinically ascertained group of human deletion (N = 25) and duplication (N = 17) carriers from the Simons Variation in Individuals Project compared with age-matched controls (N = 29 and 33, respectively). Multiple brain measures showed increased size in deletion carriers and reduced size in duplication carriers. The effects spanned global measures of intracranial volume, brain size, compartmental measures of gray matter and white matter, subcortical structures, and the cerebellum. Quantitatively, the largest effect was on the thalamus, but the collective results suggest a pervasive rather than a selective effect on the brain. Detailed analysis of cortical gray matter revealed that cortical surface area displays a strong dose-dependent effect of CNV (deletion > control > duplication), whereas average cortical thickness is less affected. These results suggest that the CNV may exert its opposing influences through mechanisms that influence early stages of embryonic brain development
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Pathways for the Oxidation of Sarin in Urban Atmospheres
Terrorists have threatened and carried out chemicalhiological agent attacks on targets in major cities. The nerve agent sarin figured prominently in one well-publicized incident. Vapors disseminating from open containers in a Tokyo subway caused thousands of casualties. High-resolution tracer transport modeling of agent dispersion is at hand and will be enhanced by data on reactions with components of the urban atmosphere. As a sample of the level of complexity currently attainable, we elaborate the mechanisms by which sarin can decompose in polluted air. A release scenario is outlined involving the passage of a gas-phase agent through a city locale in the daytime. The atmospheric chemistry database on related organophosphorus pesticides is mined for rate and product information. The hydroxyl,radical and fine-mode particles are identified as major reactants. A review of urban air chernistry/rnicrophysics generates concentration tables for major oxidant and aerosol types in both clean and dirty environments. Organic structure-reactivity relationships yield an upper limit of 10-1' cm3 molecule-' S-* for hydrogen abstraction by hydroxyl. The associated midday loss time scale could be as little as one hour. Product distributions are difficult to define but may include nontoxic organic oxygenates, inorganic phosphorus acids, sarin-like aldehydes, and nitrates preserving cholinergic capabilities. Agent molecules will contact aerosol surfaces in on the order of minutes, with hydrolysis and side-chain oxidation as likely reaction channels
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