798 research outputs found
Triamcinolone acetonide for rare ocular manifestations of pemphigus vulgaris: a case report
We present an interesting case of pemphigus vulgaris with severe and rare eye manifestations. An old lady with systemic and ocular manifestations of pemphigus vulgaris was treated with systemic corticosteroids and immunosuppressants, with no effect. Subconjunctival injection of triamcinolone acetate reduced the ocular signs and led to gradual reduction of the systemic medications
Effective optical identification of type "0-IIb" early gastric cancer with narrow band imaging magnification endoscopy, successfully treated by endoscopic submucosal dissection
Background Endoscopic submucosal dissection (ESD) is currently considered the minimal invasive endoscopic treatment for early gastric cancer. Most superficial gastric neoplastic lesions are depressed type â0-IIcâ (70-80%), while totally flat, classified as type â0-IIbâ early gastric cancer, is rarely reported (0.4%). The aim of the present study was to assess the efficacy of narrow band imaging (NBI) magnification endoscopy in identifying type â0-IIbâ early gastric cancer and ESD treatment with curative intention.Methods Twelve of 615 (2%) patients (10 males, median 72 years), treated by ESD at our center, were diagnosed as type â0-IIbâ gastric cancer. Ten had exclusively type â0-IIbâ, while two had combined types â0-IIb+IIcâ and â0-IIa+IIbâ gastric cancer. Initial diagnosis was made during screening gastroscopy, while NBI magnification endoscopy combined with indigo-carmine chromoendoscopy were also used.Results White light endoscopy showed only superficial redness. One patient with signet-ring carcinoma showed whitish appearance. Indigo-carmine chromoendoscopy showed better visualization, while NBI magnification endoscopy revealed abnormal mucosal microsurface and microvascular findings which enabled border marking. ESD with curative intention was completed without complications. Histological examination showed complete (R0) resection, in 10 patients (83%). One patient with positive margins received additional surgery (8%). Mean procedure time was 149 (range 60-190) min. One to six years post-ESD all patients remain alive.Conclusions ESD is considered a safe and effective curative treatment for type â0-IIbâ gastric cancer, resulting in long-term disease-free survival. NBI magnification endoscopy is effective for accurate optical identification and border marking of type â0-IIbâ early gastric cancer
Size resolved mass concentration and elemental composition of atmospheric aerosols over the Eastern Mediterranean area
International audienceA Berner low pressure impactor was used to collect size-segregated aerosol samples at Finokalia, located on the north-eastern coast of Crete, Greece during July 2000 and January 2001. Several samples were also collected during the summer campaign aboard the research vessel "AEGAIEO" in the Aegean Sea. Gravimetric analysis and inversion techniques yielded daily PM1 and PM10 mass concentrations. The samples were also analysed by PIXE giving the elemental size distributions of Al, Si, K, Ca, Ti, Mn, Fe, Sr, S, Cl, Ni, V, Cu, Cr, Zn, and Pb. The crustal elements and sea-salt had a unimodal supermicron size distribution. Sulphur was found predominantly in submicron fractions. K, V, and Ni exhibited a bimodal distribution with a submicron mode produced by forest fires and oil combustion. The anthropogenic elements had broad and not well-defined distributions. The time series for PM1 and PM10 mass and elemental concentrations showed both daily and seasonal variation. Higher mass concentrations were observed during two incursions of Saharan dust, whilst higher concentrations of S, Cu, Zn, and Pb were encountered in samples collected in air masses arriving from northern Greece or the western coast of Turkey. Elevated concentrations of chlorine were found in samples with air masses either originating above the Atlantic Ocean and arriving at Finokalia via western Europe or recirculating over the western coast of the Black Sea
Multi-performance optimisation framework for the selection of structural alternatives based on sustainable qualities
In recent years, the increasing demand for innovative sustainable policies in building engineering has shifted the decision rationale from traditional performance-based systems towards systems augmented by life-cycle sustainability notions. This paper investigates a novel optimisation framework, which supports the selection of buildingsâ structural alternatives at concept stage by applying multiple performance, sustainable requirements. The established model explores ways to effectively compute and process expert knowledge across different stakeholders groups into a consolidated decision-making platform supported by Lean Theory. A systematic procedure based on the Quality Function Deployment is utilised to successfully translate 16 sustainability requirements into 27 corresponding engineering design requirements. The theoretical and mathematical principles of Analytic Network Process are applied on a pilot study to build general decision clusters, identify feedback links amongst the various engineering criteria and determine their inner dependences
Assessment of wood burning versus fossil fuel contribution to wintertime black carbon and carbon monoxide concentrations in Athens, Greece
The scope of this study was to estimate the contribution of fossil fuel and
wood burning combustion to black carbon (BC) and carbon monoxide (CO)
during wintertime, in Athens. For that purpose, in situ measurements of
equivalent black carbon (eBC) and CO were simultaneously conducted in
a suburban and an urban background monitoring site in Athens during the
3Â months of winter 2014â2015. For the deconvolution of eBC into eBC emitted
from fossil fuel (BCff) and wood burning (BCwb), a
method based on the spectral dependency of the absorption of pure black
carbon and brown carbon was used. Thereafter, BCwb and
BCff estimated fractions were used along with measured CO
concentrations in a multiple regression analysis, in order to quantify the
contribution of each one of the combustion sources to the ambient CO
levels. For a comparative analysis of the results, we additionally estimated
the wood burning and fossil fuel contribution to CO, calculated on the
basis of their CO â NOx emission ratios. The
results indicate that during wintertime BC and CO are mainly emitted
by local sources within the Athens Metropolitan Area (AMA). Fossil fuel
combustion, mainly from road traffic, is found to be the major contributor to
both eBC in PM2.5 and CO ambient concentrations in AMA. However,
wintertime wood burning makes a significant contribution to the observed eBC
(of about 30 %) and CO concentrations (on average, 11 and 16 %
of total CO in the suburban and urban background sites respectively).
Both BC and CO from biomass burning (BCwb and
COwb, respectively) present a clear diurnal pattern, with
the highest concentrations during night-time, supporting the theory of local
domestic heating being their main source.</p
A Trap-Door Mechanism for Zinc Acquisition by Streptococcus pneumoniae AdcA.
Zinc is an essential element in all domains of life. Nonetheless, how prokaryotes achieve selective acquisition of zinc from the extracellular environment remains poorly understood. Here, we elucidate a novel mechanism for zinc-binding in AdcA, a solute-binding protein of Streptococcus pneumoniae. Crystal structure analyses reveal the two-domain organization of the protein and show that only the N-terminal domain (AdcAN) is necessary for zinc import. Zinc binding induces only minor changes in the global protein conformation of AdcA and stabilizes a highly mobile loop within the AdcAN domain. This loop region, which is conserved in zinc-specific solute-binding proteins, facilitates closure of the AdcAN binding site and is crucial for zinc acquisition. Collectively, these findings elucidate the structural and functional basis of selective zinc uptake in prokaryotes.
IMPORTANCE Zinc is an essential nutrient for the virulence of bacterial pathogens such as Streptococcus pneumoniae. Many Gram-positive bacteria use a two-domain lipoprotein for zinc acquisition, but how this class of metal-recruiting proteins acquire zinc and interact with the uptake machinery has remained poorly defined. We report the first structure of a two-domain lipoprotein, AdcA from S. pneumoniae, and use computational, spectroscopic, and microbiological approaches to provide new insights into the functional basis of zinc recruitment. Our findings reveal that AdcA employs a novel mechanism for zinc binding that we have termed the âtrap-doorâ mechanism, and we show how the static metal-binding site of the protein, which confers its selectivity for zinc ions, is combined with a dynamic surface element to facilitate zinc recruitment and import into the bacterium. Together, these findings expand our understanding of how bacteria acquire zinc from the environment and provide a foundation for inhibiting this process, through antimicrobial targeting of the dynamic structural elements to block bacterial zinc scavenging
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Importance of size representation and morphology in modelling optical properties of black carbon: comparison between laboratory measurements and model simulations
Black carbon (BC) from incomplete combustion of biomass or fossil fuels is the strongest absorbing aerosol component in the atmosphere. Optical properties of BC are essential in climate models for quantification of their impact on radiative forcing. The global climate models, however, consider BC to be spherical particles, which causes uncertainties in their optical properties. Based on this, an increasing number of model-based studies provide databases and parameterization schemes for the optical properties of BC, using more realistic fractal aggregate morphologies. In this study, the reliability of the different modelling techniques of BC was investigated by comparing them to laboratory measurements. The modelling techniques were examined for bare BC particles in the first step and for BC particles with organic material in the second step. A total of six morphological representations of BC particles were compared, three each for spherical and fractal aggregate morphologies. In general, the aggregate representation performed well for modelling the particle light absorption coefficient Ïabs, single-scattering albedo SSA, and mass absorption cross-section MACBC for laboratory-generated BC particles with volume mean mobility diameters dp,V larger than 100nm. However, for modelling Ă
ngström absorption exponent AAE, it was difficult to suggest a method due to size dependence, although the spherical assumption was in better agreement in some cases. The BC fractal aggregates are usually modelled using monodispersed particles, since their optical simulations are computationally expensive. In such studies, the modelled optical properties showed a 25% uncertainty in using the monodisperse size method. It is shown that using the polydisperse size distribution in combination with fractal aggregate morphology reduces the uncertainty in measured Ïabs to 10% for particles with dp,V between 60-160nm. Furthermore, the sensitivities of the BC optical properties to the various model input parameters such as the real and imaginary parts of the refractive index (mre and mim), the fractal dimension (Df), and the primary particle radius (app) of an aggregate were investigated. When the BC particle is small and rather fresh, the change in the Df had relatively little effect on the optical properties. There was, however, a significant relationship between app and the particle light scattering, which increased by a factor of up to 6 with increasing total particle size. The modelled optical properties of BC are well aligned with laboratory-measured values when the following assumptions are used in the fractal aggregate representation: mre between 1.6 and 2, mim between 0.50 and 1, Df from 1.7 to 1.9, and app between 10 and 14nm. Overall, this study provides experimental support for emphasizing the importance of an appropriate size representation (polydisperse size method) and an appropriate morphological representation for optical modelling and parameterization scheme development of BC
The X-ray Telescope of CAST
The Cern Axion Solar Telescope (CAST) is in operation and taking data since
2003. The main objective of the CAST experiment is to search for a hypothetical
pseudoscalar boson, the axion, which might be produced in the core of the sun.
The basic physics process CAST is based on is the time inverted Primakoff
effect, by which an axion can be converted into a detectable photon in an
external electromagnetic field. The resulting X-ray photons are expected to be
thermally distributed between 1 and 7 keV. The most sensitive detector system
of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system.
With the X-ray telescope of CAST a background reduction of more than 2 orders
off magnitude is achieved, such that for the first time the axion photon
coupling constant g_agg can be probed beyond the best astrophysical constraints
g_agg < 1 x 10^-10 GeV^-1.Comment: 19 pages, 25 figures and images, replaced by the revised version
accepted for publication in New Journal of Physic
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