1,318 research outputs found
The Regulation of Aggrecanase ADAMTS-4 Expression in Human Achilles Tendon and tendon-Derived Cells
Several members of the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) family have been identified as aggrecanases, whose substrates include versican, the principal large proteoglycan in the tendon extracellular matrix. We have characterized the expression of ADAMTS-4 in human Achilles tendon and tendon-derived cells. ADAMTS-4 mRNA levels were higher in ruptured tendon compared with normal tendon or chronic painful tendinopathy. In tissue extracts probed by Western blotting, mature ADAMTS-4 (68 kDa) was detected only in ruptured tendons, while processed ADAMTS-4 (53 kDa) was detected also in chronic painful tendinopathy and in normal tendon. In cultured Achilles tendon cells, transforming growth factor-ß (TGF-ß) stimulated ADAMTS-4 mRNA expression (typically 20-fold after 24 h), while interleukin-1 induced a smaller, shorter-term stimulation which synergised markedly with that induced by TGF-ß. Increased levels of immunoreactive proteins consistent with mature and processed forms of ADAMTS-4 were detected in TGF-ß-stimulated cells. ADAMTS-4 mRNA was expressed at higher levels by tendon cells in collagen gels than in monolayer cultures. In contrast, the expression of ADAMTS-1 and -5 mRNA was lower in collagen gels compared with monolayers, and these mRNA showed smaller or opposite responses to growth factors and cytokines compared with that of ADAMTS-4 mRNA. We conclude that both ADAMTS-4 mRNA and ADAMTS-4 protein processing may be differentially regulated in normal and damaged tendons and that both the matrix environment and growth factors such as TGF-ß are potentially important factors controlling ADAMTS aggrecanase activities in tendon pathology
Optical tweezers: wideband microrheology
Microrheology is a branch of rheology having the same principles as
conventional bulk rheology, but working on micron length scales and micro-litre
volumes.
Optical tweezers have been successfully used with Newtonian fluids for
rheological purposes such as determining fluid viscosity. Conversely, when
optical tweezers are used to measure the viscoelastic properties of complex
fluids the results are either limited to the material's high-frequency
response, discarding important information related to the low-frequency
behavior, or they are supplemented by low-frequency measurements performed with
different techniques, often without presenting an overlapping region of clear
agreement between the sets of results. We present a simple experimental
procedure to perform microrheological measurements over the widest frequency
range possible with optical tweezers. A generalised Langevin equation is used
to relate the frequency-dependent moduli of the complex fluid to the
time-dependent trajectory of a probe particle as it flips between two optical
traps that alternately switch on and off.Comment: 13 pages, 6 figures, submitted to Special Issue of the Journal of
Optic
Measuring storage and loss moduli using optical tweezers: broadband microrheology
We present an experimental procedure to perform broadband microrheological
measurements with optical tweezers. A generalised Langevin equation is adopted
to relate the time-dependent trajectory of a particle in an imposed flow to the
frequency-dependent moduli of the complex fluid. This procedure allows us to
measure the material linear viscoelastic properties across the widest frequency
range achievable with optical tweezers.Comment: 5 pages, 3 figure
Episodic Disturbance from Boat Anchoring Is a Major Contributor to, but Does Not Alter the Trajectory of, Long-Term Coral Reef Decline
Isolating the relative effects of episodic disturbances and chronic stressors on long-term community change is challenging. We assessed the impact of an episodic disturbance associated with human visitation (boat anchoring) relative to other drivers of long-term change on coral reefs. A one-time anchoring event at Crab Cove, British Virgin Islands, in 2004 caused rapid losses of coral and reef structural complexity that were equal to the cumulative decline over 23 years observed at an adjacent site. The abundance of small site-attached reef fishes dropped by approximately one quarter after the anchoring event, but this drop was not immediate and only fully apparent two years after the anchoring event. There was no obvious recovery from the impact, and no evidence that this episodic impact accelerated or retarded subsequent declines from other causes. This apparent lack of synergism between the effect of this episodic human impact and other chronic stressors is consistent with the few other long-term studies of episodic impacts, and suggests that action to mitigate anchor damage should yield predictable benefits
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Biogeomorphology of a Mojave Desert landscape — Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution
Terrestrial ecosystems can be more holistically understood by investigating the morphology of landscape mosaics, the assemblage of their ecological communities, and the linkages and feedbacks between the mosaics and communities. The overarching objectives of this study were to: (1) study the abiotic and biotic configurations of landform units as mosaics within a Mojave Desert chronosequence; and (2) elucidate their potential feedbacks, interactions, and dynamics during landform evolution. Seven landform units distributed over three geomorphic ages were identified, including: young bars and swales; intermediate-aged flattened bars, flattened swales, and bioturbation units; and old desert pavements and shrub zones. These landform units were characterized according to abiotic and biotic land surface properties. Landform units were statistically distinct and predictable based on a specific suite of abiotic and biotic properties. Vascular plant functional group and biological soil crust community diversity varied with geomorphology, with greatest diversity associated with bars and shrub zones and lowest diversity associated with desert pavements. Biological soil crust communities were controlled by geomorphic age, surface rock size, and protruding rocks with young bar units having the highest abundance and diversity. Perennial forbs were observed in old shrub zones with small rocks and few protruding rocks. A high clast density and a finer-sized clast distribution were found particularly in desert pavements and flattened swales, and generally inhibited biological soil crust and plant cover. Evolutionary trajectories for landforms of a lower piedmont landscape can be dominated by either abiotic and biotic landform processes. These two trajectories are distinctly different and are associated with their own unique linkages, feedbacks, and dynamics of abiotic and biotic land surface properties, producing a highly diverse desert landscape
A qualitative study of factors related to cardiometabolic risk in rural men
Abstract Background Rural men are known to have poor health behaviors, which contribute to their elevated burden of cardiometabolic disorders in the United States. Although regular physical activity, healthy eating, and avoiding tobacco can reduce cardiometabolic risk, little is known about how to engage rural men in health promotion programs. To bridge this gap in evidence, we investigate knowledge of modifiable cardiometabolic risk factors among rural men in the western United States, identify their concerns related to heart health and motivation to reduce risk, and explore individual, social, and community-level influences on heart-healthy behaviors, specifically diet, physical activity, and tobacco use. Methods We conducted seven focus groups with 54 sedentary, overweight/obese men (mean body mass index [BMI] = 31.3 ± 4.6) aged 43–88 residing in government-designated “medically underserved” rural Montana towns in September and October 2014. All sessions were audio-recorded and transcribed verbatim. Transcripts were coded and analyzed thematically using Nvivo software. Participants also completed a brief questionnaire about personal characteristics and health behaviors. These data were explored descriptively. Results Despite being classified as overweight/obese and sedentary, no participants reported to be in poor health. Many men described health relative to self-reliance and the ability to participate in outdoor recreation; concern with health appeared to be related to age. Participants were generally knowledgeable of heart-healthy behaviors, but many felt fatalistic about their own risk. Catalysts for behavior change included a serious medical event in the household and desire to reduce aging-associated functional decline. Barriers to adopting and maintaining healthy eating and physical activity habits and abstaining from tobacco included normative beliefs around masculinity and individual liberty, the limited social universe of small towns, winter weather, time constraints, and preferences for unhealthy foods. Facilitators included behavioral self-monitoring, exercising with a partner, and opportunities for preferred activities, such as hunting and team sports. Conclusions These findings provide important insight about influences on rural men’s health behaviors and provide guidance for possible intervention strategies to promote cardiometabolic health. Trial registration ClinicalTrials.gov NCT02499731 . Registered 1 July 2015
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Supplementary feeding of wild birds indirectly affects ground beetle populations in suburban gardens
Supplementary feeding of wild birds by domestic garden-holders is a globally widespread and popular form of human–wildlife interaction, particularly in urban areas. Vast amounts of energy are thus being added to garden ecosystems. However, the potential indirect effects of this activity on non-avian species have been little studied to date, with the only two previous studies taking place under experimentally manipulated conditions. Here we present the first evidence of a localised depletive effect of wild bird feeding on ground beetles (Coleoptera: Carabidae) in suburban gardens under the usual feeding patterns of the garden-holders. We trapped significantly fewer ground beetles directly under bird-feeding stations than in matched areas of habitat away from feeders. Video analysis also revealed significantly higher activity by ground-foraging birds under the feeding stations than in the control areas. Small mammal trapping revealed no evidence that these species differ in abundance between gardens with and without bird feeders. We therefore suggest that local increases in ground-foraging activity by bird species whose diets encompass arthropods as well as seed material are responsible for the reduction in ground beetle numbers. Our work therefore illustrates that providing food for wild birds can have indirect negative effects on palatable prey species under typical conditions
Boat anchoring contributes substantially to coral reef degradation in the British Virgin Islands
Community decline is often linked to anthropogenic activities. Coral reef declines, for example, have been linked to overfishing and climate change, but impacts of coastal development, pollution, and tourism have received increasing attention. Here, we isolated the impact of one little-studied aspect of recreational activity on coral reefs—damage from boat anchoring—by performing a survey of 24 sites in the British Virgin Islands (BVI) subject to varying levels of anchoring activity. The percent cover of hard corals and sea fans was reduced by a factor of ∼1.7 and ∼2.6 respectively at highly anchored sites. Hard coral colonies were 40% smaller in surface area and ∼60% less dense at sites experiencing high anchoring frequency. In addition, highly anchored sites supported only ∼60% of the species richness of little anchored sites. Frequently anchored sites were ∼60% as structurally complex and supported less than half as many fish as those rarely anchored, with 5 of 7 fish functional groups affected. Roughly 24% of BVI coral reef by area appears suitable for anchoring, suggesting that impacts associated with boat anchoring may be both locally severe and more pervasive than previously appreciated
Changes in brain white matter structure are associated with urine proteins in urologic chronic pelvic pain syndrome (UCPPS): A MAPP Network study
Routine sensitive enquiry of adult interpersonal trauma in community mental health teams: an audit of the initial assessment tool
This audit aimed to evaluate the utility of the Initial Assessment Tool (IAT) in documenting routine sensitive enquiry of adult interpersonal trauma within three Community Mental Health Teams (CMHTs) in North-East Glasgow. In addition, it sought to evaluate if disclosures informed patient risk assessments and if patients were signposted to additional support services. 57% of 90 IATs had evidence of routine sensitive enquiry. Of 51 casefiles with evidence of routine sensitive enquiry, 61% had evidence of the information informing their risk assessments and 14% had documented recommendations of support organisations. The IAT appeared able to assist clinicians with routine sensitive enquiry in adulthood. However, there may be advantage in supporting staff understanding of how to ask questions to specific populations and to use this information to inform treatment planning. Given the prevalence of adult interpersonal trauma experienced by patients presenting to CMHTs, trauma-informed approaches to care should be implemented
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