788 research outputs found
Body mass index as a predictor of the presence but not the severity of coronary artery disease evaluated by cardiac computed tomography
Background The relation between body mass index (BMI) and coronary artery disease (CAD) extension remains controversial. The aim of this study was to evaluate the correlation between BMI and CAD extension documented by coronary computed tomography angiography (CCTA). Methods and results Prospective registry including 1706 consecutive stable patients that performed CCTA (dual source scanner) for the evaluation of CAD. The population was stratified by BMI: normal 530 (31.1\%), overweight 802 (47.0\%) and obesity 374 (21.9\%). BMI was significantly higher in patients with CAD (27.74.3vs 26.8 +/- 4.3kg/m(2), p5 segments with plaque (15.4\% patients). The prevalence of SIS >5 among the BMI classes was: 18.7\%, 13.7\% and 13.6\% for normal, overweight and obesity respectively (p values for the specific classes versus all other patients: 0.241, 0.450 and 0.663). Conclusions In this population of stable patients undergoing CCTA for suspected CAD, BMI was an independent predictor of its presence, but was not correlated with the coronary disease severity.publishersversionpublishe
Using a logical model to predict the growth of yeast
<p>Abstract</p> <p>Background</p> <p>A logical model of the known metabolic processes in <it>S. cerevisiae </it>was constructed from iFF708, an existing Flux Balance Analysis (FBA) model, and augmented with information from the KEGG online pathway database. The use of predicate logic as the knowledge representation for modelling enables an explicit representation of the structure of the metabolic network, and enables logical inference techniques to be used for model identification/improvement.</p> <p>Results</p> <p>Compared to the FBA model, the logical model has information on an additional 263 putative genes and 247 additional reactions. The correctness of this model was evaluated by comparison with iND750 (an updated FBA model closely related to iFF708) by evaluating the performance of both models on predicting empirical minimal medium growth data/essential gene listings.</p> <p>Conclusion</p> <p>ROC analysis and other statistical studies revealed that use of the simpler logical form and larger coverage results in no significant degradation of performance compared to iND750.</p
Mining metabolites: extracting the yeast metabolome from the literature
Text mining methods have added considerably to our capacity to extract biological knowledge from the literature. Recently the field of systems biology has begun to model and simulate metabolic networks, requiring knowledge of the set of molecules involved. While genomics and proteomics technologies are able to supply the macromolecular parts list, the metabolites are less easily assembled. Most metabolites are known and reported through the scientific literature, rather than through large-scale experimental surveys. Thus it is important to recover them from the literature. Here we present a novel tool to automatically identify metabolite names in the literature, and associate structures where possible, to define the reported yeast metabolome. With ten-fold cross validation on a manually annotated corpus, our recognition tool generates an f-score of 78.49 (precision of 83.02) and demonstrates greater suitability in identifying metabolite names than other existing recognition tools for general chemical molecules. The metabolite recognition tool has been applied to the literature covering an important model organism, the yeast Saccharomyces cerevisiae, to define its reported metabolome. By coupling to ChemSpider, a major chemical database, we have identified structures for much of the reported metabolome and, where structure identification fails, been able to suggest extensions to ChemSpider. Our manually annotated gold-standard data on 296 abstracts are available as supplementary materials. Metabolite names and, where appropriate, structures are also available as supplementary materials
Synthesis, structural and magnetic characterization of lead-metaniobate/cobalt-ferrite nanocomposite films deposited by pulsed laser ablation
Detailed structural, microstructural and magnetic measurements were performed on (PbNb2O6)(1-x) -(CoFe2O4) (x) nanocomposite thin films deposited by laser ablation on Si(001)\Pt substrates, with different cobalt ferrite concentrations. The tuning of the lead concentration, due to the lead volatility, was found to be particularly important in order to obtain the orthorhombic (ferroelectric) lead niobate phase. The lattice parameter of CoFe2O4 was below the bulk value, indicating the presence of compressive strains on this phase. A magnetic anisotropy was observed, which favored the orientation of the magnetization in the direction perpendicular to the plane of the films, for cobalt ferrite concentrations 40-50 %. The shape, stress and magnetocrystalline anisotropy fields on the composites were calculated and compared. It was found that the perpendicular magnetic anisotropy was induced by the presence of strain on the ferrite phase in the films.- This work has been supported by Fundacao para a Ciencia e Tecnologia (FCT) and FEDER, through the projects POCI/CTM/60181/2004 and PTDC/CTM/099415/2008. J. Barbosa and I. T. Gomes gratefully acknowledge Ph.D. grants from Fundacao para a Ciencia e Tecnologia (SFRH/BD/41913/2007 and SFRH/BD/36348/2007, respectively).info:eu-repo/semantics/publishedVersio
Community ecology of the Middle Miocene primates of La Venta, Colombia: the relationship between ecological diversity, divergence time, and phylogenetic richness
It has been suggested that the degree of ecological diversity that characterizes a primate community correlates positively with both its phylogenetic richness and the time since the members of that community diverged (Fleagle and Reed in Primate communities. Cambridge University Press, New York, pp 92–115, 1999). It is therefore questionable whether or not a community with a relatively recent divergence time but high phylogenetic richness would be as ecologically variable as a community with similar phylogenetic richness but a more distant divergence time. To address this question, the ecological diversity of a fossil primate community from La Venta, Colombia, a Middle Miocene platyrrhine community with phylogenetic diversity comparable with extant platyrrhine communities but a relatively short time since divergence, was compared with that of modern Neotropical primate communities. Shearing quotients and molar lengths, which together are reliable indicators of diet, for both fossil and extant species were plotted against each other to describe the dietary “ecospace” occupied by each community. Community diversity was calculated as the area of the minimum convex polygon encompassing all community members. The diversity of the fossil community was then compared with that of extant communities to test whether the fossil community was less diverse than extant communities while taking phylogenetic richness into account. Results indicate that the La Ventan community was not significantly less ecologically diverse than modern communities, supporting the idea that ecological diversification occurred along with phylogenetic diversification early in platyrrhine evolution
Rhodopsin Mutant P23H Destabilizes Rod Photoreceptor Disk Membranes
Mutations in rhodopsin cause retinitis pigmentosa in humans and retinal degeneration in a multitude of other animals. We utilized high-resolution live imaging of the large rod photoreceptors from transgenic frogs (Xenopus) to compare the properties of fluorescently tagged rhodopsin, Rho-EGFP, and RhoP23H-EGFP. The mutant was abnormally distributed both in the inner and outer segments (OS), accumulating in the OS to a concentration of ∼0.1% compared to endogenous opsin. RhoP23H-EGFP formed dense fluorescent foci, with concentrations of mutant protein up to ten times higher than other regions. Wild-type transgenic Rho-EGFP did not concentrate in OS foci when co-expressed in the same rod with RhoP23H-EGFP. Outer segment regions containing fluorescent foci were refractory to fluorescence recovery after photobleaching, while foci in the inner segment exhibited recovery kinetics similar to OS regions without foci and Rho-EGFP. The RhoP23H-EGFP foci were often in older, more distal OS disks. Electron micrographs of OS revealed abnormal disk membranes, with the regular disk bilayers broken into vesiculotubular structures. Furthermore, we observed similar OS disturbances in transgenic mice expressing RhoP23H, suggesting such structures are a general consequence of mutant expression. Together these results show that mutant opsin disrupts OS disks, destabilizing the outer segment possibly via the formation of aggregates. This may render rods susceptible to mechanical injury or compromise OS function, contributing to photoreceptor loss
Clonal diversity and detection of carbapenem resistance encoding genes among multidrug-resistant Acinetobacter baumannii isolates recovered from patients and environment in two intensive care units in a Moroccan hospital
Background
Carbapenem-resistant Acinetobacter baumannii has recently been defined by the World Health Organization as a critical pathogen. The aim of this study was to compare clonal diversity and carbapenemase-encoding genes of A. baumannii isolates collected from colonized or infected patients and hospital environment in two intensive care units (ICUs) in Morocco.
Methods
The patient and environmental sampling was carried out in the medical and surgical ICUs of Mohammed V Military teaching hospital from March to August 2015. All A. baumannii isolates recovered from clinical and environmental samples, were identified using routine microbiological techniques and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed using disc diffusion method. The carbapenemase-encoding genes were screened for by PCR. Clonal relatedness was analyzed by digestion of the DNA with low frequency restriction enzymes and pulsed field gel electrophoresis (PFGE) and the multi locus sequence typing (MLST) was performed on two selected isolates from two major pulsotypes.
Results
A total of 83 multidrug-resistant A. baumannii isolates were collected: 47 clinical isolates and 36 environmental isolates. All isolates were positive for the bla OXA51-like and bla OXA23-like genes. The coexistence of bla NDM-1 /bla OXA-23-like and bla OXA 24-like /bla OXA-23-like were detected in 27 (32.5%) and 2 (2.4%) of A. baumannii isolates, respectively. The environmental samples and the fecally-colonized patients were significantly identified (p < 0.05) as the most common sites of isolation of NDM-1-harboring isolates. PFGE grouped all isolates into 9 distinct clusters with two major groups (0007 and 0008) containing up to 59% of the isolates. The pulsotype 0008 corresponds to sequence type (ST) 195 while pulsotype 0007 corresponds to ST 1089.The genetic similarity between the clinical and environmental isolates was observed in 80/83 = 96.4% of all isolates, belonging to 7 pulsotypes.
Conclusion
This study shows that the clonal spread of environmental A. baumannii isolates is related to that of clinical isolates recovered from colonized or infected patients, being both associated with a high prevalence of the bla OXA23-like and bla NDM-1genes. These findings emphasize the need for prioritizing the bio-cleaning of the hospital environment to control and prevent the dissemination of A. baumannii clonal lineages
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