68 research outputs found
Covariation in Plant Functional Traits and Soil Fertility within Two Species-Rich Forests
The distribution of plant species along environmental gradients is expected to be predictable based on organismal function. Plant functional trait research has shown that trait values generally vary predictably along broad-scale climatic and soil gradients. This work has also demonstrated that at any one point along these gradients there is a large amount of interspecific trait variation. The present research proposes that this variation may be explained by the local-scale sorting of traits along soil fertility and acidity axes. Specifically, we predicted that trait values associated with high resource acquisition and growth rates would be found on soils that are more fertile and less acidic. We tested the expected relationships at the species-level and quadrat-level (20×20 m) using two large forest plots in Panama and China that contain over 450 species combined. Predicted relationships between leaf area and wood density and soil fertility were supported in some instances, but the majority of the predicted relationships were rejected. Alternative resource axes, such as light gradients, therefore likely play a larger role in determining the interspecific variability in plant functional traits in the two forests studied
Pathogens and host immunity in the ancient human oral cavity.
Calcified dental plaque (dental calculus) preserves for millennia and entraps biomolecules from all domains of life and viruses. We report the first, to our knowledge, high-resolution taxonomic and protein functional characterization of the ancient oral microbiome and demonstrate that the oral cavity has long served as a reservoir for bacteria implicated in both local and systemic disease. We characterize (i) the ancient oral microbiome in a diseased state, (ii) 40 opportunistic pathogens, (iii) ancient human-associated putative antibiotic resistance genes, (iv) a genome reconstruction of the periodontal pathogen Tannerella forsythia, (v) 239 bacterial and 43 human proteins, allowing confirmation of a long-term association between host immune factors, 'red complex' pathogens and periodontal disease, and (vi) DNA sequences matching dietary sources. Directly datable and nearly ubiquitous, dental calculus permits the simultaneous investigation of pathogen activity, host immunity and diet, thereby extending direct investigation of common diseases into the human evolutionary past
Cardiovascular disease and the role of oral bacteria
In terms of the pathogenesis of cardiovascular disease (CVD) the focus has traditionally been on dyslipidemia. Over the decades our understanding of the pathogenesis of CVD has increased, and infections, including those caused by oral bacteria, are more likely involved in CVD progression than previously thought. While many studies have now shown an association between periodontal disease and CVD, the mechanisms underpinning this relationship remain unclear. This review gives a brief overview of the host-bacterial interactions in periodontal disease and virulence factors of oral bacteria before discussing the proposed mechanisms by which oral bacterial may facilitate the progression of CVD
Survival and growth of tree seedlings as a function of seed size in a gallery forest under restoration
Intraspecific phenotypic variability of plant functional traits in contrasting mountain grasslands habitats
Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study
Purpose Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes
Structural modeling and validation of an active twist model rotor blade
DLR has been researching on active twist rotor blade control intensively for at least 15 years now. This research work included the design and manufacturing of model rotor blades with in the blade skin integrated actuators. As a main subject, numerical benefit studies with respect to rotor noise, vibration, and performance were carried out with DLR's rotor simulation code S4. Since this simulation code is based on a modal synthesis, it uses the natural blade frequencies and mode shapes to model the blade dynamics. Both, natural blade frequencies as well as mode shapes, are computed in advance employing a finite element beam model of the blade. Each beam element possesses certain structural properties that are derived from an ANSYS model for certain cross sections of the blade. Since model rotor blades are built for wind tunnel testing, they are highly instrumented with sensors and therefore vary in their structural properties along span. Modifications in the structural properties due to the instrumentation are not included in the ANSYS model. However, to account for these variations, two different experimental methods have been developed. This way, the most important structural properties can be determined for the real blade and the structural blade model can be improved. The paper describes the development of an advanced structural blade model for rotor simulation purposes and shows a validation of the structural blade model based on the measured non-rotating and rotating frequencies
Improvement in Periodontal Health and Antibody Response to Heat-Shock Proteins
There is evidence that periodontal disease may be associated with atherosclerosis due to cross-reactivity of bacterial GroEL immunity with human heat shock protein 60 (hHSP60). Objective: To examine changes in serum antibody responses to Porphyromonas gingivalis, hHSP60, and P. gingivalis GroEL following improvement in periodontal health in patients with cardiovascular disease (CVD) and in patients with high cardiovascular (CV) risk and low CV risk. Methods: Patients were selected from two large longitudinal studies and had undergone yearly periodontal examinations and peripheral blood collections. CVD patients (n=15) selected from one study had experienced a significant CV event while patients derived from the other study had not experienced a CV event. These latter patients were further classified according to CV risk (≥6 classical risk factors=high CV risk n=13; ≤1 classical risk factor=low CV risk n=14). Patients demonstrating a quantifiable improvement in periodontal health (≥62% reduction in number of sites with probing depth≥4mm) from the baseline visit were selected. Serum IgG antibody levels to P.gingivalis, hHSP60, and P.gingivalis GroEL were measured using ELISA. Results: Median reductions, after improvement in periodontal health, in antibody levels to P.gingivalis GroEL differed significantly across the three groups (Kruskal-Wallis
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