813 research outputs found
An Extremely Bright Echo Associated With SN 2002hh
We present new, very late-time optical photometry and spectroscopy of the
interesting Type II-P supernova, SN 2002hh, in NGC 6946. Gemini/GMOS-N has been
used to acquire visible spectra at six epochs between 2004 August and 2006
July, following the evolution of the SN from age 661 to 1358 days. Few optical
spectra of Type II supernovae with ages greater than one year exist. In
addition, g'r'i' images were acquired at all six epochs. The spectral and
photometric evolution of SN 2002hh has been very unusual. Measures of the
brightness of this SN, both in the R and I bands as well as in the H-alpha
emission flux, show no significant fading over an interval of nearly two years.
The most straightforward explanation for this behavior is that the light being
measured comes not only from the SN itself but also from an echo off of nearby
dust. Echoes have been detected previously around several SNe but these echoes,
at their brightest, were ~8 mag below the maximum brightness of the SN. At V~21
mag, the putative echo dominates the light of SN 2002hh and is only ~4 mag
below the outburst's peak brightness. There is an estimated 6 magnitudes of
total extinction in V towards SN 2002hh. The proposed explanation of a
differential echo/SN absorption is inconsistent with the observed BVRI colors.Comment: 24 pages, 6 figures. Accepted for publication in the Ap
The influence of age and exercise training status on left ventricular systolic twist mechanics in healthy males—an exploratory study
Age-related differences in twist may be mitigated with exercise training, although this remains inconclusive. Moreover, temporal left ventricular (LV) systolic twist mechanics, including early-systolic (twistearly), and beyond peak twist (twistpeak) alone, have not been considered. Therefore, further insights are required to ascertain the influence of age and training status on twist mechanics across systole. Forty males were included and allocated into 1 of 4 groups based on age and training status: young recreationally active (YRA, n = 9; 28 ± 5 years), old recreationally active (ORA, n = 10; 68 ± 6 years), young trained (YT, n = 10; 27 ± 6 years), and old trained (OT, n = 11, 64 ± 4 years) groups. Two-dimensional speckle-tracking echocardiography was performed to determine LV twist mechanics, including twistearly, twistpeak, and total twist (twisttotal), by considering the nadir on the twist time-curve during early systole. Twisttotal was calculated by subtracting twistearly from their peak values. LV twistpeak was higher in older than younger men (p = 0.036), while twistpeak was lower in the trained than recreationally-active (p = 0.004). Twistpeak is underestimated compared with twisttotal (p < 0.001), and when early-systolic mechanics were considered, to calculate twisttotal, the age effect (p = 0.186) was dampened. LV twist was higher in older than younger age, with lower twist in exercise-trained than recreationally-active males. Twistpeak is underestimated when twistearly is not considered, with novel observations demonstrating that the age effect was dampened when considering twistearly. These findings elucidated a smaller age effect when early phases of systole are considered, while lower LV systolic mechanics were observed in older aged trained than recreationally-active males
Improved physical health in middle-older aged golf caddies following 24-weeks of high-volume physical activity
Background: The physical demands of golf caddying, including walking while carrying a golf bag, may potentially affect body composition, and markers of metabolic, cardiovascular, and musculoskeletal health. Therefore, this study examined the impact of 24 weeks of caddying on physical health in middle-older aged males. Methods: Eleven full-time experienced male caddies (age: 59 [8] y; caddying experience: 14 [12] y) were recruited from a local golf course. The following were assessed at preseason and after 24 weeks of caddying (March–September 2022): body composition, heart rate, blood pressure, blood lipids, and performance tests (static and dynamic balance, strength, and submaximal fitness). Physical activity (PA) levels were assessed at preseason and at the mid-point of the caddying season. Across the caddying season, participants completed a monthly average of 24.0 (3.8) rounds. Results: Following the caddying season, improvements in static balance (Δ = 13.5 s), dynamic balance (Δ = −1.8 s), and lower back absolute strength (Δ = 112.8 N), and muscle quality (Δ = 2.0 N·kg−1) were observed (all P < .05). Additionally, blood lipids, including total cholesterol (Δ = −0.6 mmol·L−1), high-density lipoprotein cholesterol (Δ = 0.1 mmol·L−1), low-density lipoprotein cholesterol (Δ = −0.6 mmol·L−1) (all P < .05), and body composition, including body mass (Δ = −2.7 kg), fat mass (Δ = −1.9 kg), fat percentage (Δ = −1.4%), fat-to-muscle ratio (Δ = −0.03), and body mass index (Δ = −0.9 kg·m−2) (all P < .05) improved. Caddying did not offer beneficial changes to cardiovascular variables or cardiorespiratory fitness (P > .05), while coronary heart disease risk score decreased (Δ = −3.3%) (P < .05). In relation to PA, light- (Δ = 145 min) and moderate-intensity (Δ = 71 min) PA, moderate to vigorous PA (Δ = 73 min), and total PA (Δ = 218 min) between preseason and the mid-point of the caddying season increased, while sedentary time (Δ = −172 min) decreased (all P < .05). Conclusion: Golf caddying can provide several physical health benefits such as improvements in various markers of cardiometabolic health, lower back absolute strength, and static and dynamic balance. The physical health improvements that caddying offers is likely contributed to by increased PA volume and intensity through walking on the golf course. Therefore, caddying may represent a feasible model for increasing PA volume and intensity and achieve physical health–related benefits
No excess of mitochondrial DNA deletions within muscle in progressive multiple sclerosis
BACKGROUND: Mitochondrial dysfunction is an established feature of multiple sclerosis (MS). We recently described high levels of mitochondrial DNA (mtDNA) deletions within respiratory enzyme-deficient (lacking mitochondrial respiratory chain complex IV with intact complex II) neurons and choroid plexus epithelial cells in progressive MS. OBJECTIVES: The objective of this paper is to determine whether respiratory enzyme deficiency and mtDNA deletions in MS were in excess of age-related changes within muscle, which, like neurons, are post-mitotic cells that frequently harbour mtDNA deletions with ageing and in disease. METHODS: In progressive MS cases (n=17), known to harbour an excess of mtDNA deletions in the central nervous system (CNS), and controls (n=15), we studied muscle (paraspinal) and explored mitochondria in single fibres. Histochemistry, immunohistochemistry, laser microdissection, real-time polymerase chain reaction (PCR), long-range PCR and sequencing were used to resolve the single muscle fibres. RESULTS: The percentage of respiratory enzyme-deficient muscle fibres, mtDNA deletion level and percentage of muscle fibres harbouring high levels of mtDNA deletions were not significantly different in MS compared with controls. CONCLUSION: Our findings do not provide support to the existence of a diffuse mitochondrial abnormality involving multiple systems in MS. Understanding the cause(s) of the CNS mitochondrial dysfunction in progressive MS remains a research priority
Characterization of co-circulating swine influenza A viruses in North America and the identification of a novel H1 genetic clade with antigenic significance.
Multiple genetically and antigenically distinct hemagglutinin genes of the H1 and H3 influenza A virus (IAV) subtypes co-circulate in North American swine. This diversity has evolved by repeated transmission of IAVs from humans to swine and subsequent antigenic drift in swine. To understand the evolutionary dynamics of these diverse HA lineages in North American swine, we undertook a phylogenetic analysis of 1576 H1 and 607 H3 HA gene segments, as well as 834 N1 and 1293 N2 NA gene segments, and 2126 M gene segments. These data revealed yearly co-circulation of H1N1, H1N2, and H3N2 viruses, with three HA clades representing the majority of the HA sequences: of the H1 viruses, 42% were classified as H1δ1 and 40.6% were classified as H1γ; and of the H3 viruses 53% were classified as cluster IV-A H3N2. We detected a genetically distinct minor clade consisting of 37 H1 viruses isolated between 2003 and 2013, which we classified as H1γ-2. We estimated that this clade circulated in swine since approximately 1995, but it was not detected in swine until 2003. Though this clade only represents 1.07% of swine H1 sequences reported over the past 10 years, hemagglutination inhibition (HI) assays demonstrated that representatives of this clade of viruses are antigenically distinct, and, when measured using antigenic cartography, were as many as 7 antigenic units from other H1γ viruses. Therefore vaccines against the contemporary H1γ viruses are not likely to cross-protect against γ-2 viruses. The long-term circulation of these γ-2 viruses suggests that minor populations of viruses may be underreported in the national dataset given the long branch lengths and gaps in detections. The identification of these γ-2 viruses demonstrates the need for robust surveillance to capture the full diversity IAVs in swine in the USA and the importance of antigenic drift in the diversification and emergence of new antigenic variants in swine, which complicates vaccine design.Funding was provided by USDA-ARS and USDA355
APHIS-VS by the Supplemental Appropriations Act of 2009. NSL was funded by USDA-ARS SCA agreement number 58-3625-2-103F and the EC FP7 award number 259949. TKA was funded by USDA
ARS SCA agreement number 58-3625-4-070.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S0168170215000799
A personalised smartphone-delivered just-in-time adaptive intervention (JITABug) to increase physical activity in older adults: Feasibility pilot study (Preprint)
Background:
Just-in-time adaptive interventions (JITAIs) provide real time in-the-moment behavior change support to people when they need it most. JITAIs could be a viable way to provide personalized physical activity (PA) support to older adults in the community. However, it is unclear how feasible it is to remotely deliver a PA intervention through a smartphone to older adults or how acceptable they would find a JITAI targeting PA in everyday life.
Objective:
The aims of this study are to describe the development of JitaBug, a personalized smartphone-delivered JITAI designed to support older adults to increase or maintain their PA level, assess the feasibility of conducting an effectiveness trial of the JitaBug intervention, and explore the acceptability of JitaBug among older adults in a free-living setting.
Methods:
The intervention was developed using the Behavior Change Wheel and consisted of a wearable activity tracker (Fitbit) and a companion smartphone app (JitaBug) that delivered goal-setting, planning, reminders, and JITAI messages to encourage achievement of personalized PA goals. Message delivery was tailored based on time of day, real time PA tracker data, and weather conditions. We tested the feasibility of remotely delivering the intervention with older adults in a 6-week trial. Data collection involved assessment of PA through accelerometery and activity tracker, self-reported mood and mental well-being through ecological momentary assessment, and contextual information on PA through voice memos. Feasibility outcomes included recruitment capability and adherence to the intervention, intervention delivery in the wild, appropriateness of data collection methodology, adverse events, and participant satisfaction.
Results:
Of the 46 recruited older adults (aged 56-72 years), 31 (67%) completed the intervention. The intervention was successfully delivered as intended; 87% (27/31) of the participants completed the intervention independently; 94% (2247/2390) of the PA messages were successfully delivered; 99% (2239/2261) of the Fitbit and 100% (2261/2261) of the weather data calls were successful. Valid and usable wrist-worn accelerometer data were obtained from 90% (28/31) of the participants at baseline and follow-up. On average, the participants recorded 50% (7.9/16, SD 7.3) of the voice memos, 38% (3.3/8, SD 4.2) of the mood assessments, and 50% (2.1/4, SD 1.6) of the well-being assessments through the app. Overall acceptability of the intervention was very good (23/30, 77% expressed satisfaction). Participant feedback suggested that more diverse and tailored PA messages, app use reminders, technical refinements, and an improved user interface could improve the intervention and make it more appealing.
Conclusions:
This study suggests that a smartphone-delivered JITAI is an acceptable way to support PA in older adults in the community. Overall, the intervention is feasible; however, based on user feedback, the JitaBug app requires further technical refinements that may enhance use, engagement, and user satisfaction before moving to effectiveness trials
A 22-year Southern Sky Survey for Transient and Variable Radio Sources using the Molonglo Observatory Synthesis Telescope
We describe a 22-year survey for variable and transient radio sources,
performed with archival images taken with the Molonglo Observatory Synthesis
Telescope (MOST). This survey covers 2775 \unit{deg^2} of the sky south of
at an observing frequency of 843 MHz, an angular
resolution of 45 \times 45 \csc | \delta| \unit{arcsec^2} and a sensitivity
of 5 \sigma \geq 14 \unit{mJy beam^{-1}}. We describe a technique to
compensate for image gain error, along with statistical techniques to check and
classify variability in a population of light curves, with applicability to any
image-based radio variability survey. Among radio light curves for almost 30000
sources, we present 53 highly variable sources and 15 transient sources. Only 3
of the transient sources, and none of the variable sources have been previously
identified as transient or variable. Many of our variable sources are suspected
scintillating Active Galactic Nuclei. We have identified three variable sources
and one transient source that are likely to be associated with star forming
galaxies at , but whose implied luminosity is higher than the
most luminous known radio supernova (SN1979C) by an order of magnitude. We also
find a class of variable and transient source with no optical counterparts.Comment: Accepted for publication in MNRAS. 34 pages, 30 figures, 7 table
Habitual exercise influences carotid artery strain and strain rate, but not cognitive function in healthy middle‑aged females
Purpose Aging females are at risk of declining vascular and cognitive function. Exercise can augment both factors independently; however, the influence of exercise on their interdependence is less clearly understood. Ultrasound speckle tracking is a sensitive novel measure of arterial aging but has not previously been used in middle-aged females. We aimed to elucidate the potential interactions between vascular and cognitive variables in active aging females.
Methods Twelve active (56 ± 5 years; V̇ O2peak : 34.5 ± 6.1 ml.kg.min−1) and 13 inactive (57 ± 4 years; 22.8 ± 2.6 ml.kg.min−1)
healthy middle-aged females were included. Ultrasound speckle tracking assessed short-axis common carotid artery (CCA)
compliance via peak circumferential strain (PCS) and strain rate (PSR) at rest, during, and after 3-min isometric handgrip exercise. Flow-mediated dilation (FMD) of the brachial artery was assessed using ultrasound. Cognitive function was measured
using Verbal Fluency, Trail Making, Stroop, and Digit Span tests.
Results PCS (P = 0.003) and PSR (P = 0.004), were higher in the active cohort. FMD was similar between groups (P > 0.05).
Minimal differences in cognitive function existed between groups, although the inactive group performed better in one test of animal Verbal Fluency (P 0.05).
Conclusion This is the first study to assess PCS and PSR in middle-aged females and demonstrates that active middle-aged
females exhibit a superior carotid artery profile compared to their inactive counterparts. However, PCS and PSR of the carotid artery may not be linked with cognitive function in middle-aged females
Endorepellin causes endothelial cell disassembly of actin cytoskeleton and focal adhesions through α2β1 integrin
Endorepellin, the COOH-terminal domain of the heparan sulfate proteoglycan perlecan, inhibits several aspects of angiogenesis. We provide evidence for a novel biological axis that links a soluble fragment of perlecan protein core to the major cell surface receptor for collagen I, α2β1 integrin, and provide an initial investigation of the intracellular signaling events that lead to endorepellin antiangiogenic activity. The interaction between endorepellin and α2β1 integrin triggers a unique signaling pathway that causes an increase in the second messenger cAMP; activation of two proximal kinases, protein kinase A and focal adhesion kinase; transient activation of p38 mitogen-activated protein kinase and heat shock protein 27, followed by a rapid down-regulation of the latter two proteins; and ultimately disassembly of actin stress fibers and focal adhesions. The end result is a profound block of endothelial cell migration and angiogenesis. Because perlecan is present in both endothelial and smooth muscle cell basement membranes, proteolytic activity during the initial stages of angiogenesis could liberate antiangiogenic fragments from blood vessels' walls, including endorepellin
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