1,427 research outputs found
Cytokine mRNA expression responses to resistance, aerobic, and concurrent exercise in sedentary middle-aged men
Concurrent resistance and aerobic exercise (CE) is recommended to ageing populations, though is postulated to induce diminished acute molecular responses. Given that contraction-induced cytokine mRNA expression reportedly mediates remunerative postexercise molecular responses, it is necessary to determine whether cytokine mRNA expression may be diminished after CE. Eight middle-aged men (age, 53.3 ±1.8 years; body mass index, 29.4 ± 1.4 kg·m-2) randomly completed (balanced for completion order) 8 × 8 leg extensions at 70% maximal strength (RE), 40 min of cycling at 55% of peak aerobic workload (AE), or (workload-matched) 50% RE and 50% AE (CE). Muscle (vastus lateralis) was obtained pre-exercise, and at 1 h and 4 h postexercise, and analyzed for changes of glycogen concentration, tumor necrosis factor (TNF)α, TNF receptor-1 and -2 (TNF-R1 and TNF-R2, respectively), interleukin (IL)-6, IL-6R, IL-1β, and IL-1 receptor-antagonist (IL-1ra). All exercise modes upregulated cytokine mRNA expression at 1hpostexercise comparably (TNFα, TNF-R1, TNF-R2, IL-1β, IL-6) (p 0.05). Moreover, AE and RE upregulated IL-1β and IL-1ra expression, whereas CE upregulated IL-1β expression only (p 0.05). In conclusion, in middle-aged men, all modes induced commensurate cytokine mRNA expression at 1 h postexercise; however, only CE resulted in ameliorated expression at 4 h postexercise. Whether the RE or AE components of CE are independently or cumulatively sufficient to upregulate cytokine responses, or whether they collectively inhibit cytokine mRNA expression, remains to be determined
Fine-Scale Genetic Structure Arises during Range Expansion of an Invasive Gecko
Processes of range expansion are increasingly important in light of current concerns about invasive species and range shifts due to climate change. Theoretical studies suggest that genetic structuring may occur during range expansion. Ephemeral genetic structure can have important evolutionary implications, such as propagating genetic changes along the wave front of expansion, yet few studies have shown evidence of such structure. We tested the hypothesis that genetic structure arises during range expansion in Hemidactylus mabouia, a nocturnal African gecko recently introduced to Florida, USA. Twelve highly variable microsatellite loci were used to screen 418 individuals collected from 43 locations from four sampling sites across Florida, representing a gradient from earlier (∼1990s) to very recent colonization. We found earlier colonized locations had little detectable genetic structure and higher allelic richness than more recently colonized locations. Genetic structuring was pronounced among locations at spatial scales of tens to hundreds of meters near the leading edge of range expansion. Despite the rapid pace of range expansion in this introduced gecko, dispersal is limited among many suitable habitat patches. Fine-scale genetic structure is likely the result of founder effects during colonization of suitable habitat patches. It may be obscured over time and by scale-dependent modes of dispersal. Further studies are needed to determine if such genetic structure affects adaptation and trait evolution in range expansions and range shifts
The development and validation of measures to assess cooking skills and food skills
BACKGROUND: With the increase use of convenience food and eating outside the home environment being linked to the obesity epidemic, the need to assess and monitor individuals cooking and food skills is key to help intervene where necessary to promote the usage of these skills. Therefore, this research aimed to develop and validate a measure for cooking skills and one for food skills, that are clearly described, relatable, user-friendly, suitable for different types of studies, and applicable across all sociodemographic levels.
METHODS: Two measures were developed in light of the literature and expert opinion and piloted for clarity and ease of use. Following this, four studies were undertaken across different cohorts (including a sample of students, both 'Food preparation novices' and 'Experienced food preparers', and a nationally representative sample) to assess temporal stability, psychometrics, internal consistency reliability and construct validity of both measures. Analysis included T-tests, Pearson's correlations, factor analysis, and Cronbach's alphas, with a significance level of 0.05.
RESULTS: Both measures were found to have a significant level of temporal stability (PÂ <Â 0.001). Factor analysis revealed three factors with eigenvalues over 1, with two items in a third factor outside the two suggested measures. The internal consistency reliability for the cooking skills confidence measure ranged from 0.78 to 0.93 across all cohorts. The food skills confidence measure's Cronbach's alpha's ranged from 0.85 to 0.94. The two measures also showed a high discriminate validity as there were significant differences (PÂ <Â 0.05 for cooking skills confidence and PÂ <Â 0.01 for food skills confidence) between Food preparation novices' and 'Experienced food preparers.'
CONCLUSIONS: The cooking skills confidence measure and the food skills confidence measure have been shown to have a very satisfactory reliability, validity and are consistent over time. Their user-friendly applicability make both measures highly suitable for large scale cross-sectional, longitudinal and intervention studies to assess or monitor cooking and food skills levels and confidence
Evaluation of the performance of three tenodesis techniques for the treatment of scapholunate instability: flexion-extension and radial-ulnar deviation
Nitrogen uptake and internal recycling in Zostera marina exposed to oyster farming: eelgrass potential as a natural biofilter
Oyster farming in estuaries and coastal lagoons frequently overlaps with the distribution of seagrass meadows, yet there are few studies on how this aquaculture practice affects seagrass physiology. We compared in situ nitrogen uptake and the productivity of Zostera marina shoots growing near off-bottom longlines and at a site not affected by oyster farming in San Quintin Bay, a coastal lagoon in Baja California, Mexico. We used benthic chambers to measure leaf NH4 (+) uptake capacities by pulse labeling with (NH4)-N-15 (+) and plant photosynthesis and respiration. The internal N-15 resorption/recycling was measured in shoots 2 weeks after incubations. The natural isotopic composition of eelgrass tissues and vegetative descriptors were also examined. Plants growing at the oyster farming site showed a higher leaf NH4 (+) uptake rate (33.1 mmol NH4 (+) m(-2) day(-1)) relative to those not exposed to oyster cultures (25.6 mmol NH4 (+) m(-2) day(-1)). We calculated that an eelgrass meadow of 15-16 ha (which represents only about 3-4 % of the subtidal eelgrass meadow cover in the western arm of the lagoon) can potentially incorporate the total amount of NH4 (+) excreted by oysters (similar to 5.2 x 10(6) mmol NH4 (+) day(-1)). This highlights the potential of eelgrass to act as a natural biofilter for the NH4 (+) produced by oyster farming. Shoots exposed to oysters were more efficient in re-utilizing the internal N-15 into the growth of new leaf tissues or to translocate it to belowground tissues. Photosynthetic rates were greater in shoots exposed to oysters, which is consistent with higher NH4 (+) uptake and less negative delta C-13 values. Vegetative production (shoot size, leaf growth) was also higher in these shoots. Aboveground/belowground biomass ratio was lower in eelgrass beds not directly influenced by oyster farms, likely related to the higher investment in belowground biomass to incorporate sedimentary nutrients
Food-Web Structure of Seagrass Communities across Different Spatial Scales and Human Impacts
Seagrass beds provide important habitat for a wide range of marine species but are threatened by multiple human impacts in coastal waters. Although seagrass communities have been well-studied in the field, a quantification of their food-web structure and functioning, and how these change across space and human impacts has been lacking. Motivated by extensive field surveys and literature information, we analyzed the structural features of food webs associated with Zostera marina across 16 study sites in 3 provinces in Atlantic Canada. Our goals were to (i) quantify differences in food-web structure across local and regional scales and human impacts, (ii) assess the robustness of seagrass webs to simulated species loss, and (iii) compare food-web structure in temperate Atlantic seagrass beds with those of other aquatic ecosystems. We constructed individual food webs for each study site and cumulative webs for each province and the entire region based on presence/absence of species, and calculated 16 structural properties for each web. Our results indicate that food-web structure was similar among low impact sites across regions. With increasing human impacts associated with eutrophication, however, food-web structure show evidence of degradation as indicated by fewer trophic groups, lower maximum trophic level of the highest top predator, fewer trophic links connecting top to basal species, higher fractions of herbivores and intermediate consumers, and higher number of prey per species. These structural changes translate into functional changes with impacted sites being less robust to simulated species loss. Temperate Atlantic seagrass webs are similar to a tropical seagrass web, yet differed from other aquatic webs, suggesting consistent food-web characteristics across seagrass ecosystems in different regions. Our study illustrates that food-web structure and functioning of seagrass habitats change with human impacts and that the spatial scale of food-web analysis is critical for determining results
Branch Mode Selection during Early Lung Development
Many organs of higher organisms, such as the vascular system, lung, kidney,
pancreas, liver and glands, are heavily branched structures. The branching
process during lung development has been studied in great detail and is
remarkably stereotyped. The branched tree is generated by the sequential,
non-random use of three geometrically simple modes of branching (domain
branching, planar and orthogonal bifurcation). While many regulatory components
and local interactions have been defined an integrated understanding of the
regulatory network that controls the branching process is lacking. We have
developed a deterministic, spatio-temporal differential-equation based model of
the core signaling network that governs lung branching morphogenesis. The model
focuses on the two key signaling factors that have been identified in
experiments, fibroblast growth factor (FGF10) and sonic hedgehog (SHH) as well
as the SHH receptor patched (Ptc). We show that the reported biochemical
interactions give rise to a Schnakenberg-type Turing patterning mechanisms that
allows us to reproduce experimental observations in wildtype and mutant mice.
The kinetic parameters as well as the domain shape are based on experimental
data where available. The developed model is robust to small absolute and large
relative changes in the parameter values. At the same time there is a strong
regulatory potential in that the switching between branching modes can be
achieved by targeted changes in the parameter values. We note that the sequence
of different branching events may also be the result of different growth
speeds: fast growth triggers lateral branching while slow growth favours
bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is
sufficient to generate pattern that correspond to the observed branching modesComment: Initially published at PLoS Comput Bio
Regional Genetic Structure in the Aquatic Macrophyte Ruppia cirrhosa Suggests Dispersal by Waterbirds
The evolutionary history of the genus Ruppia has been shaped by hybridization, polyploidisation and vicariance that have resulted in a problematic taxonomy. Recent studies provided insight into species circumscription, organelle takeover by hybridization, and revealed the importance of verifying species identification to avoid distorting effects of mixing different species, when estimating population connectivity. In the present study, we use microsatellite markers to determine population diversity and connectivity patterns in Ruppia cirrhosa including two spatial scales: (1) from the Atlantic Iberian coastline in Portugal to the Siculo-Tunisian Strait in Sicily and (2) within the Iberian Peninsula comprising the Atlantic-Mediterranean transition. The higher diversity in the Mediterranean Sea suggests that populations have had longer persistence there, suggesting a possible origin and/or refugial area for the species. The high genotypic diversities highlight the importance of sexual reproduction for survival and maintenance of populations. Results revealed a regional population structure matching a continent-island model, with strong genetic isolation and low gene flow between populations. This population structure could be maintained by waterbirds, acting as occasional dispersal vectors. This information elucidates ecological strategies of brackish plant species in coastal lagoons, suggesting mechanisms used by this species to colonize new isolated habitats and dominate brackish aquatic macrophyte systems, yet maintaining strong genetic structure suggestive of very low dispersal.Fundacao para a Cincia e Tecnologia (FCT, Portugal) [PTDC/MAR/119363/2010, BIODIVERSA/0004/2015, UID/Multi/04326/2013]Pew FoundationSENECA FoundationMurcia Government, Spain [11881/PI/09]FCT Investigator Programme-Career Development [IF/00998/2014]Spanish Ministry of Education [AP2008-01209]European Community [00399/2012]info:eu-repo/semantics/publishedVersio
The Re-Emergence of Percutaneous Fasciotomy in the Management of Dupuytren’s Disease
Dupuytren’s disease is a common condition. Its management has gradually evolved but still remains a source of much controversy. Recently there has been a resurgence in the popularity of percutaneous needle fasciotomy. It is a simple method that uses a hypodermic needle as a scalpel blade. It is usually performed in the out-patient setting under local anaesthesia without a tourniquet. It has few complications and allows almost immediate return to work with few restrictions
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