749 research outputs found
Optical coherence tomography angiography findings in pigmented paravenous chorioretinal atrophy
Purpose:To analyze the retino-choroidal vascular characteristics of patients affected by pigmented paravenous chorio-retinal atrophy by means of optical coherence tomography (OCT) angiography.Methods:This study was designed as an observational, cross-sectional case series. Multimodal imaging included fundus autofluorescence, structural OCT, and OCT angiography. The quantitative OCT angiography analyses included the calculation of the vessel density and choriocapillaris porosity.Results:Overall, 12 patients (24 eyes) affected by pigmented paravenous chorio-retinal atrophy were recruited. Structural OCT of the areas involved by pigmented paravenous chorio-retinal atrophy as visualized on the fundus autofluorescence showed a complete ellipsoid zone and external limiting membrane absence, with thinning of ganglion cell complex, outer nuclear layer, and outer plexiform layer, but associated with the optical partial preservation of the retinal pigment epithelium. Optical coherence tomography angiography quantitative assessment of the retinal regions affected by PPRCA, as visualized by fundus autofluorescence, was characterized by normal vessel density at the level of superficial capillary plexus but significantly altered vessel density of deep capillary plexus and choriocapillaris, with higher choriocapillaris porosity. The presence of macular atrophy was significantly correlated with worse deep capillary plexus and choriocapillaris vessel density values. Furthermore, a statistically significant correlation between the fundus autofluorescence patterns and the retinal vascular status was found.Conclusion:Optical coherence tomography angiography quantitative analyses in pigmented paravenous chorio-retinal atrophy demonstrate a specific impairment at the level of the deep capillary plexus, which could in turn bring about a thinning of ganglion cell complex and outer nuclear layer. The alterations at the level of the choriocapillaris and the choroid, in general, could then represent a secondary effect
A multi-layer extension of the stochastic heat equation
Motivated by recent developments on solvable directed polymer models, we
define a 'multi-layer' extension of the stochastic heat equation involving
non-intersecting Brownian motions.Comment: v4: substantially extended and revised versio
Investigations of Carbon Nitride-Supported Mn3O4 Oxide Nanoparticles for ORR
Earth-abundant Mn-based oxide nanoparticles are supported on carbon nitride using two different immobilization methods and tested for the oxygen reduction reaction. Compared to the metal free CN, the immobilization of Mn oxide enhances not only the electrocatalytic activity but also the selectivity towards the 4e- reduction reaction of O-2 to H2O. The XPS analysis reveals the interaction of the pyridine N species with Mn3O4 nanoparticles being particularly beneficial. This interaction is realized-although to a limited extent-when preparing the catalysts via impregnation; via the oleic acid route it is not observed. Whilst this work shows the potential of these systems to catalyze the ORR, the main limiting factor is still the poor conductivity of the support which leads to overpotential
New conditional symmetries and exact solutions of nonlinear reaction-diffusion-convection equations. II
In the first part of this paper math-ph/0612078, a complete description of
Q-conditional symmetries for two classes of reaction-diffusion-convection
equations with power diffusivities is derived. It was shown that all the known
results for reaction-diffusion equations with power diffusivities follow as
particular cases from those obtained in math-ph/0612078 but not vise versa. In
the second part the symmetries obtained in are successfully applied for
constructing exact solutions of the relevant equations. In the particular case,
new exact solutions of nonlinear reaction-diffusion-convection (RDC) equations
arising in application and their natural generalizations are found
Are Au nanoparticles on oxygen free supports catalytically active?
Gold nanoparticles Au NPs on oxygen free supports were examined using near ambient pressure X ray photoelectron spectroscopy NAP XPS under CO oxidation conditions, and ex situ using scanning electron microscopy SEM and transmission electron microscopy TEM . Our observations demonstrate that Au NPs supported on carbon materials are inactive, regardless of the preparation method. Ozone O3 treatment of carbon supports leads oxygen functionalization of the supports. When subsequently exposed to a CO feed, CO is oxidized by the functionalized sites of the carbon support via a stoichiometric pathway. Microscopy reveals that the reaction with CO does not change the morphology of the Au NPs. In situ XPS reveals that the O3 treatment gives rise to additional Au 4f and O 1s peaks at binding energies of 85.25 85.6 eV and 529.4 530 eV, respectively, which are assigned to the presence of Au oxide. A surface oxide phase is formed during the activation of Au NPs supported on Au foil by O3 treatment. However, this phase decomposes in vacuum and the remaining low coordinative atoms do not have sufficient catalytic properties to oxidize CO, so the size reduction of Au NPs and or oxidation of Au NPs is not sufficient to activate A
Potential Activity of Albino Grifola frondosa Mushroom Extract against Biofilm of Meticillin-Resistant Staphylococcus aureus
Mushroom extracts are a rich source of natural compounds with antimicrobial properties, which are able to prevent, to some extent, the growth of foodborne pathogens. The aim of this study was to investigate the potential of extracts from albino Grifola frondosa (GF), commonly known as maitake, to inhibit the growth of some bacteria and the biofilm production by Staphylococcus aureus.
We obtained not only a significant reduction of OD score between biofilm and biofilm plus albino G. frondosa extract group, but also a reduction of category of biofilm. In addition, we observed a significant presence of isolates with strong category for the biofilm group and a significant presence of isolates with absent category for the biofilm plus albino G. frondosa extract group. These results
confirm that the use of albino G. frondosa extract reduces in significant way the presence of biofilm. Our results suggest and confirm that albino G. frondosa extracts could be employed as functional food and could be used as a natural additive for food process control and food safety
Influence of synthesis conditions on the structure of nickel nanoparticles and their reactivity in selective asymmetric hydrogenation
Unsupported and SiO2-supported Ni nanoparticles (NPs), were synthesised via hot-injection colloidal route using oleylamine (OAm) and trioctylphosphine (TOP) as reducing and protective agents, respectively. By adopting a multi-length scale structural characterization, it was found that by changing equivalents of OAM and TOP not only the size of the nanoparticles is affected but also the Ni electronic structure. The synthetized NPs were modified with (R,R)-tartaric acid (TA) and investigated in the asymmetric hydrogenation of methyl acetoacetate to chiral methyl-3-hydroxy butyrate. The comparative analysis of structure and catalytic performance for the synthetized catalysts has enabled us to identify a Ni metallic active surface, whereby the activity increases with the size of the metallic domains. Conversely, at the high conversion obtained for the unsupported NPs no impact of particle size on the selectivity was observed. (R)-selectivity was very high only on catalysts containing positively charged Ni species such as over the SiO2-supported Ni oxide NPs. This work shows that the chiral modification of metallic Ni NPs with TA is insufficient to maintain high selectivity towards the (R)-enantiomer at long reaction time and provide guidance for the engineering of long-term stable enantioselective catalysts
ANATOMICAL DISSECTION AND ANALYSIS OF THE STRUCTURES OF THE UPPER LIMB
In 2015, a whole body dissection course was proposed by the University of Palermo, Palermo, Italy, thanks to the cooperation with the University of Malta, Msida, Malta. The purpose of this study was to show the the difference between the studyof anatomy on books and on corpses. The article focuses its attention on the dissection method of the upper limb. The astudy was performed on two corpses, a male and a female, by using a basic surgeon kit. Blunt dissection method was used for fasciae, innards and to isolate vascular-nervous structures from the fat; we used scalped for cutis, sub cutis, muscles, fasciae, veins, arteries and nerves of the upper limb from the shoulder to the hand. The upper limb dissection shows the difference between how a real body appears and shows the difference between how a real body appears and how books represent it
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula
Organic ligands are a key factor determining the
availability of dissolved iron (DFe) in the high-nutrient low-chlorophyll
(HNLC) areas of the Southern Ocean. In this study, organic speciation of Fe
is investigated along a natural gradient of the western Antarctic Peninsula,
from an ice-covered shelf to the open ocean. An electrochemical approach,
competitive ligand exchange – adsorptive cathodic stripping voltammetry
(CLE-AdCSV), was applied. Our results indicated that organic ligands in the
surface water on the shelf are associated with ice-algal exudates, possibly
combined with melting of sea ice. Organic ligands in the deeper shelf water
are supplied via the resuspension of slope or shelf sediments. Further offshore,
organic ligands are most likely related to the development of phytoplankton
blooms in open ocean waters. On the shelf, total ligand concentrations
([Lt]) were between 1.2 and 6.4 nM eq. Fe. The organic
ligands offshore ranged between 1.0 and 3.0 nM eq. Fe. The southern boundary
of the Antarctic Circumpolar Current (SB ACC) separated the organic ligands
on the shelf from bloom-associated ligands offshore. Overall, organic ligand
concentrations always exceeded DFe concentrations (excess ligand
concentration, [L′] = 0.8–5.0 nM eq. Fe). The [L′] made up to 80 % of
[Lt], suggesting that any additional Fe input can be stabilized in the
dissolved form via organic complexation. The denser modified Circumpolar
Deep Water (mCDW) on the shelf showed the highest complexation capacity of
Fe (αFe'L; the product of [L′] and conditional binding
strength of ligands, KFe'Lcond). Since Fe is also supplied by shelf
sediments and glacial discharge, the high complexation capacity over
the shelf can keep Fe dissolved and available for local primary productivity
later in the season upon sea-ice melting.</p
Seed and peel essential oils obtained from Campomanesia adamantium fruit inhibit inflammatorty and pain parameters in rodents.
This study evaluated the anti-inflammatory and antinociceptive activities and toxicology of essential oils from peel (EOP) and seed (EOS) of C. adamantium fruits in animal models.e0157107. Creative Commons Attribution (CC BY) license
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