198 research outputs found
Floral ontogeny in Dialiinae (Caesalpinioideae: Cassieae), a study in organ loss and instability
AbstractThe Caesalpinioideae are widely variable in their floral ontogeny, and among caesalpinioids, members of the polyphyletic tribe Cassieae are particularly diverse. Within the Cassieae, the monophyletic Dialiinae clade is also marked by a high degree of organ loss, particularly in the largest genus, Dialium. The purpose of this work is to explore the ontogeny of several previously undocumented species of the diverse Dialiinae clade, with the goal of building a more complete picture of floral development and evolution in this group and especially within Dialium. We have documented the floral ontogeny of six species of the Dialiinae; four from Dialium, as well as Poeppigia procera and Mendoravia dumaziana. Mode and timing of organ initiation were mostly consistent across the Dialium species studied. With the exception of Dialium dinklagei, which undergoes helical calyx initiation, all flowers initiated sepals bidirectionally. In the instances of both gains and losses of floral organs in Dialium, one trend is apparent — an absence of abaxial organs. Gains in both sepals and stamens occur in the adaxial median position, while stamens and petals which are lost are always the ventral-most organs. Organ initiation in Poeppigia and Mendoravia is unlike that seen in Dialium. Poeppigia shows a ventral to dorsal unidirectional sepal initiation, while both Poeppigia and Mendoravia display near-synchronous initiation of the corolla and staminal whorls. The taxa examined here exemplify the apparent lack of developmental canalisation seen in caesalpinioid legumes. This ontogenetic plasticity is reflective of the morphological diversity shown by flowers across the subfamily, representing what has been described as an “experimental” phase in legume floral evolution
Outcome of elective endovascular abdominal aortic aneurysm repair in nonagenarians
ObjectiveCompared with open repair of abdominal aortic aneurysms (AAA), endovascular repair (EVAR) is associated with decreased perioperative morbidity and mortality in a standard patient population. This study sought to determine if the advantage of EVAR extends to patients aged ≥90 years.MethodsThis was a retrospective review from a prospectively maintained computerized database. Of the 322 patients aged ≥80 treated with EVAR from January 1997 to November 2007, 24 (1.9%) were aged ≥90. Mean age was 91.5 ± 1.5 years (range, 90-95 years), and 83.3% were men. Mean aneurysm size was 6.8 cm (range, 5.2-8.7 cm).ResultsMean procedural blood loss was 490 mL (range, 100-4150 mL), and 20.8% required an intraoperative transfusion. Mean postoperative length of stay was 6.0 days, (median, 4 days; mode, 1 day; range, 1-42 days), with 33.3% of patients discharged on the first postoperative day. Amongst the 24 patients, there were 6 (25.0%) perioperative major adverse events, and 2 patients died, for a perioperative mortality rate of 8.3%. Mean follow-up was 20.5 months (range, 1-49 months). Overall, three patients (12.5%) required a secondary intervention, comprising thrombectomy, angioplasty, and proximal cuff extension. No patients required conversion to open repair. Two patients (8.3%) died of AAA rupture at 507 and 1254 days. Freedom from all-cause mortality was 83.3% at 1 year and 19.3% at 5 years. Freedom from aneurysm-related mortality was 87.5% at 1 year and 73.2% at 5 years. Endoleak occurred in five patients (20.8%), with three type I and two of indeterminate type; of these, two patients with type I endoleak underwent secondary intervention at 153 and 489 days after EVAR, of which one case was successful.ConclusionOur study supports that EVAR in nonagenarians is associated with acceptable procedural success and perioperative morbidity and mortality. The medium-term results suggest that EVAR may be of limited benefit in very carefully selected patients who are aged ≥90 years
Evaluation of Biopolymer Materials and Synthesis Techniques to Develop a Rod-Shaped Biopolymer Surrogate for Legionella pneumophila
Biopolymer microparticles have been developed for applications that require biocompatibility and biodegradability, such as drug delivery. In this study, we assessed the production of microparticles using carnauba wax, κ-carrageenan, alginate, and poly (lactic-co-glycolic acid) (PLGA) with the aim of developing a novel, DNA-tracer-loaded, biopolymer surrogate with a size, shape, surface charge, and relative hydrophobicity similar to stationary-phase Legionella pneumophila to mimic the bacteria’s mobility and persistence in engineered water systems. We found that the type and concentration of biopolymer, reaction conditions, and synthesis methods affected the morphology, surface charge, relative hydrophobicity, and DNA tracer loading efficiency of the biopolymer microparticles produced. Carnauba wax, κ-carrageenan, and alginate (Protanal®, and low and medium viscosity) produced highly polydisperse microspheres. In contrast, PLGA and alginate-CaCO3 produced uniform microspheres and rod-shaped microparticles, respectively, with high DNA tracer loading efficiencies (PLGA 70% and alginate-CaCO3 95.2 ± 5.7%) and high reproducibilities. Their synthesis reproducibility was relatively high. The relative hydrophobicity of PLGA microspheres closely matched the cell surface hydrophobicity of L. pneumophila but not the bacterial morphology, whereas the polyelectrolyte layer-by-layer assembly was required to enhance the relative hydrophobicity of alginate-CaCO3 microparticles. Following this surface modification, alginate-CaCO3 microparticles represented the best match to L. pneumophila in size, morphology, surface charge, and relative hydrophobicity. This new biopolymer surrogate has the potential to be used as a mimic to study the mobility and persistence of L. pneumophila in water systems where the use of the pathogen is impractical and unsafe
Linking Self-Incompatibility, Dichogamy, and Flowering Synchrony in Two Euphorbia Species: Alternative Mechanisms for Avoiding Self-Fertilization?
Background: Plant species have several mechanisms to avoid selfing such as dichogamy or a self-incompatibility response.
Dichogamy in a single flower may reduce autogamy but, to avoid geitonogamy, plants must show flowering
synchronization among all their flowers (i.e. synchronous dichogamy). It is hypothesized that one species would not
simultaneously show synchronous dichogamy and self-incompatibility because they are redundant mechanisms to reduce
selfing; however, this has not been accurately assessed.
Methodology/Principal Findings: This expectation was tested over two years in two natural populations of the closely
related Mediterranean spurges Euphorbia boetica and E. nicaeensis, which completely avoid autogamy by protogyny at the
cyathia level. Both spurges showed a high population synchrony (Z,79), and their inflorescences flower synchronously. In E.
nicaeensis, there was no overlap among the cyathia in anthesis of successive inflorescence levels and the overlap between
sexual phases of cyathia of the same inflorescence level was uncommon (4–16%). In contrast, E. boetica showed a high
overlap among consecutive inflorescence levels (74–93%) and between sexual phases of cyathia of the same inflorescence
level (48–80%). The flowering pattern of both spurges was consistent in the two populations and over the two successive
years. A hand-pollination experiment demonstrated that E. nicaeensis was strictly self-compatible whereas E. boetica was
partially self-incompatible.
Conclusions/Significance: We propose that the complex pattern of synchronized protogyny in E. nicaeensis prevents
geitonogamous crosses and, consequently, avoids selfing and inbreeding depression. In E. boetica, a high probability of
geitonogamous crosses may occur but, alternatively, this plant escapes selfing through a self-incompatibility response. We
posit that synchronous dichogamy and physiological self-incompatibility do not co-occur in the same species because each
process is sufficiently effective in avoiding self-fertilization.España Ministerio de Ciencia y Tecnología PLO CGL2005-03731; CGL2008-02533-EEspaña Ministerio de Ciencia y Tecnología MA CGL2009-0825
Postinjection Endophthalmitis in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT)
To describe the incidence and outcomes of endophthalmitis after intravitreal injections of anti-VEGF agents in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT) and to assess the effect of use of prophylactic topical antimicrobials on incidence
Cardiovascular Response to Beta-Adrenergic Blockade or Activation in 23 Inbred Mouse Strains
We report the characterisation of 27 cardiovascular-related traits in 23 inbred mouse strains. Mice were phenotyped either in response to chronic administration of a single dose of the β-adrenergic receptor blocker atenolol or under a low and a high dose of the β-agonist isoproterenol and compared to baseline condition. The robustness of our data is supported by high trait heritabilities (typically H2>0.7) and significant correlations of trait values measured in baseline condition with independent multistrain datasets of the Mouse Phenome Database. We then focused on the drug-, dose-, and strain-specific responses to β-stimulation and β-blockade of a selection of traits including heart rate, systolic blood pressure, cardiac weight indices, ECG parameters and body weight. Because of the wealth of data accumulated, we applied integrative analyses such as comprehensive bi-clustering to investigate the structure of the response across the different phenotypes, strains and experimental conditions. Information extracted from these analyses is discussed in terms of novelty and biological implications. For example, we observe that traits related to ventricular weight in most strains respond only to the high dose of isoproterenol, while heart rate and atrial weight are already affected by the low dose. Finally, we observe little concordance between strain similarity based on the phenotypes and genotypic relatedness computed from genomic SNP profiles. This indicates that cardiovascular phenotypes are unlikely to segregate according to global phylogeny, but rather be governed by smaller, local differences in the genetic architecture of the various strains
BluePort: A Platform to Study the Eosinophilic Response of Mice to the Bite of a Vector of Leishmania Parasites, Lutzomyia longipalpis Sand Flies
transmission in residents of endemic areas has been attributed to the acquisition of immunity to sand fly salivary proteins. One theoretical way to accelerate the acquisition of this immunity is to increase the density of antigen-presenting cells at the sand fly bite site. Here we describe a novel tissue platform that can be used for this purpose. sand flies. Results presented indicate that a shift in the inflammatory response, from neutrophilic to eosinophilic, is the main histopathological feature associated with the immunity acquired through repeated exposure to the bite of sand flies, and that the BluePort tissue compartment could be used to accelerate this process. In addition, changes observed inside the BluePort parenchyma indicate that it could be used to study complex immunobiological processes, and to develop ectopic secondary lymphoid structures.Understanding the characteristics of the dermal response to the bite of sand flies is a critical element of strategies to control leishmaniasis using vaccines that target salivary proteins. Finding that dermal eosinophilia is such a prominent component of the anti-salivary immunity induced by repeated exposure to sand fly bites raises one important consideration: how to avoid the immunological conflict derived from a protective Th2-driven immunity directed to sand fly saliva with a protective Th1-driven immunity directed to the parasite. The BluePort platform is an ideal tool to address experimentally this conundrum
Parameters affecting water-hammer wave attenuation, shape and timing. Part 2: Case studies
This two-part paper investigates parameters that may significantly affect water-hammer wave attenuation, shape and timing. Possible sources that may affect the waveform predicted by classical water-hammer theory include unsteady friction, cavitation (including column separation and trapped air pockets), a number of fluid–structure interaction effects, viscoelastic behaviour of the pipe-wall material, leakages and blockages. Part 1 of this two-part paper presents the mathematical tools needed to model these sources. Part 2 of the paper presents a number of case studies showing how these modelled sources affect pressure traces in a simple reservoir-pipeline-valve system. Each case study compares the obtained results with the standard (classical) water-hammer model, from which conclusions are drawn concerning the transient behaviour of real systems.Anton Bergant, Arris S. Tijsseling, John P. Vítkovský, Dídia I. C. Covas, Angus R. Simpson and Martin F. Lamber
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