6,329 research outputs found
Immunohistochemical characterization of the 'intimal proliferation' phenomenon in Sneddon's syndrome and essential thrombocythaemia
Cellular changes were immunocytochemically characterized in skin vessels of five patients with idiopathic generalized racemose livedo (Sneddon's syndrome), and one patient with localized racemose livedo associated with essential thrombocythaemia. Antibodies against alpha-smooth muscle-actin, tropomyosin, desmin, vimentin, factor VIII-related antigen, human endothelial cells (CD31), human macrophages (CD68), and HLA-DR positive cells (CR3/43) were used. Conventional light microscopy showed, in all cases, intimal thickening of ascending arteries and arterioles as a result of an accumulation of cells and extracellular hyalinized material. None of the specimens showed infiltration with polymorphonuclear leucocytes or macrophages. The cells in the region of the intimal hyperplasia showed intense positive immunostaining for alpha-smooth muscle actin and tropomyosin. Staining for the intermediate filament desmin was localized to the resident smooth muscle cells of the media, whereas staining for vimentin was found in all types of cells in both the intima and media. Positive immunostaining for factor VIII-related antigen and CD31 was strictly confined to the endothelial cells lining the narrowed lumina of the vessels. No positive staining with either antibody was observed in totally occluded vessels. Cells in the subintimal space did not show reactivity for CD68 in any of the specimens, but two cases showed solitary cells with positive staining for HLA-DR in this region. There were no differences in staining pattern between Sneddon's syndrome and essential thrombocythaemia with any of the antibodies. Our results support the assumption that the 'intimal proliferation' in both diseases is caused by colonization of the subendothelial space with contractile cells of possible smooth muscle origin.(ABSTRACT TRUNCATED AT 250 WORDS
Mimicry and ultrastructural analogy between the semi-aquatic grasshopper Paulinia acuminata (Orthoptera: Pauliniidae) and its foodplant, the water-fern Salvinia auriculata (Filicatae: Salviniaceae)
The semi-aquatic grasshopper Paulinia acuminata is mimetically protected by a striking similarity to its foodplant, the floating fern Salvinia auriculata. A SEM study of the cuticula of young grasshopper nymphs and the Salvinia leaf surface reveals a similar ultrastructure of epicuticular waxes which makes both organisms extremely water repellent
Data Analysis Techniques for Fan Performance in Highly-Distorted Flows from Boundary Layer Ingesting Inlets
The design of a unique distortion-tolerant fan for a high-bypass ratio boundary-layer ingesting propulsion system has been completed and a rig constructed and tested in the NASA Glenn 8x6 wind tunnel. Processing the data from the experiment presented some interesting challenges because of the complexity of the experimental setup and the flow through the test rig. The experiment was run in three phases, each of which employed a unique complement of inlet throat and fan face instrumentation to avoid the blockage that would have resulted from simultaneously installing all of the rakes. The measurement from the individual test points were subsequently combined to compute the overall stage performance. A CFD model of the experiment was used to gain understanding of the flow field and to test some of the techniques proposed for interpolating and extrapolating the measurements into regions where measurements were not made. This capability became extremely useful when it was discovered that there was an unexpected total temperature distortion in the tunnel. The CFD model was modified by inserting a total temperature profile at the upstream boundary that mimicked the measured distortion where measurements were available and that CFD solution was used to investigate methods to infer the complete total temperature field at the fan face
High-sensitivity cardiac troponin T and copeptin assays to improve diagnostic accuracy of exercise stress test in patients with suspected coronary artery disease
Background: The average diagnostic sensitivity of exercise stress tests (ESTs) is lower than that of other non-invasive cardiac stress tests. The aim of the study was to examine whether high-sensitivity cardiac troponin T (hs-cTnT) or copeptin concentrations rise in response to inducible myocardial ischaemia and may improve the diagnostic accuracy of ESTs.
Methods and results: An EST was performed stepwise on a bicycle ergometer by 383 consecutive patients with suspected or progression of coronary artery disease (CAD). In addition venous blood samples for measurement of hs-cTnT and copeptin were collected prior to EST, at peak exercise, and 4 h after EST. Coronary angiography was assessed for all patients. Patients with significant CAD (n=224) were more likely to be male and older compared to patients with non-significant CAD (n=169). Positive EST was documented in 125 (55.8%) patients with significant CAD and in 69 (43.4%) patients with non-significant CAD. Copeptin and hs-cTnT concentrations at baseline were higher in patients with significant CAD (copeptin: 10.8 pmol/l (interquartile range (IQR) 8.115.6) vs 9.4 pmol/l (IQR 7.113.9); p=0.04; hs-cTnT: 3.0 ng/l (IQR <3.05.4) vs <3.0 ng/l (IQR <3.0); p=0.006). Hs-cTnT improved sensitivity (61.6% vs 55.8%), specificity (67.7% vs 56.6%) and the positive predictive value (PPV) (72.3% vs 64.4%) and negative (55.2% vs 47.6%) predictive value (NPV) of EST. Copeptin could not improve sensitivity (55.4% vs 55.8%) and reduced specificity, PPV and NPV.
Conclusions: The measurement of hs-cTnT during EST improves sensitivity, specificity, and positive and negative predictive values. In contrast, measurement of copeptin does not improve diagnostic sensitivity and reduces specificity
XMM-Newton observations of the BL Lac MS 0737+7441
We report on the XMM-Newton observations of the BL Lac object MS 0737.9+7441
during the performance verification phase. A simple power-law fit provides an
adequate description of the integrated spectrum in the 0.2-10 keV energy band.
The photon index is slightly steeper in the EPIC pn data with 2.38+-0.01
compared to the EPIC MOS data (2.28+-0.01). The difference is most probably due
to the present uncertainties in the calibration of the EPIC MOS and EPIC pn
data sets. We report evidence for intrinsic absorption in the distant BL Lac
above the Galactic column N_H,Gal=3.2*10^20 cm^-2 which is N_H,fit(z=0.315)=
(2.70+-0.20)*10^20cm^-2 in the EPIC pn data and N_H,fit(z=0.315)=
(3.25+-0.25)*10^20cm^-2 in the EPIC MOS data assuming neutral gas and solar
abundances. The flux variations are found to be of the order of 10 %.Comment: 4 pages, 4 Figures, accepted for publication in the special A&A
Letters issue for XMM-Newto
A Tale of Three Watersheds: Nonpoint Source Pollution and Conservation Practices across Iowa
Resource /Energy Economics and Policy, Q25,
ЗНАХІДКИ УКРАЇНСЬКИХ НАТІЛЬНИХ ХРЕСТІВ В СЕРЕДНЬОМУ І НИЖНЬОМУ ПРИСАМАР’Ї
Територія Пониззя Присамар’я здавна привертала увагу дослідників, проте їх зацікавленість належала, переважно археологічним пам’яткам від доби каменю – бронзи та ранньозалізного часу. Пам’ятки пізніших часів, тим більш козацької епохи, переважно залишалися поза вивченням [28, с.28, 29- 33 с.214]. Винятковим явищем у цьому плані є роботи керованої Д.І.Яворницьким новобудівної Дніпрогесівської експедиції НКПросу 1927-1932 років [14, с.11-12], коли вперше на зазначених територіях були відкриті і досліджувалися не лише неолітичні і матеріали ранньобронзової доби, а й алано-болгарські пам’ятки, поселення доби Київської Русі, козацькі поховання XVII-XVIII ст. Д.І.Яворницький першим проводив археологічні розвідки на теренах Богородицької фортеці і її посаду під час робіт Дніпрогесівської експедиції 1927-1932 років [13; 19, с. 256-257] (у фондах ДІМ ім. Д.І.Яворницького знаходиться близько 80 натільних хрестів «із запорозьких поховань», зібраних вченим, але у матеріалах його розвідок місця знахідок часто не фіксувалися, через це знахідки не паспортизовувалися, що ускладнює ідентифікацію матеріалів). У повоєнні роки і до кінця 1980-х матеріали доби середньовіччя і козаччини з гирла Самари цікавили, переважно, краєзнавців і аматорів. У 1960-1970 рр. брати В.В. та Е.В.Бінкевичі знаходили монети й інші старожитності на Ігренському півострові: про ці знахідки з пониззя Самари лише стисло згадано в праці „Городок старинный запорожский Самарь с перевозом [1]. В цей же час і на цій же території краєзнавець з Придніпровська Є.Богуш збирав натільні хрести, колекція яких по смерті аматора була розпродана спадкоємцями частинами. У 2001 році науково-дослідною Лабораторією археології Подніпров’я ДНУ під керівництвом професора І.Ф.Ковальової на території Богородицьком фортеці і її посаду були розпочаті планомірні розвідки і розкопки
Dirac-Brueckner Hartree-Fock Approach: from Infinite Matter to Effective Lagrangians for Finite Systems
One of the open problems in nuclear structure is how to predict properties of
finite nuclei from the knowledge of a bare nucleon-nucleon interaction of the
meson-exchange type. We point out that a promising starting point consists in
Dirac-Brueckner-Hartree-Fock (DBHF) calculations us- ing realistic
nucleon-nucleon interactions like the Bonn potentials, which are able to
reproduce satisfactorily the properties of symmetric nuclear matter without the
need for 3-body forces, as is necessary in non-relativistic BHF calculations.
However, the DBHF formalism is still too com- plicated to be used directly for
finite nuclei. We argue that a possible route is to define effective
Lagrangians with density-dependent nucleon-meson coupling vertices, which can
be used in the Relativistic Hartree (or Relativistic Mean Field (RMF)) or
preferrably in the Relativistic Hartree- Fock (RHF) approach. The
density-dependence is matched to the nuclear matter DBHF results. We review the
present status of nuclear matter DBHF calculations and discuss the various
schemes to construct the self-energy, which lead to differences in the
predictions. We also discuss how effective Lagrangians have been constructed
and are used in actual calculations. We point out that completely consistent
calculations in this scheme still have to be performed.Comment: 16 pages, to be published in Journal of Physics G: Nuclear and
Particle Physics, special issue
Spatial structure of Mn-Mn acceptor pairs in GaAs
The local density of states of Mn-Mn pairs in GaAs is mapped with
cross-sectional scanning tunneling microscopy and compared with theoretical
calculations based on envelope-function and tight-binding models. These
measurements and calculations show that the crosslike shape of the Mn-acceptor
wavefunction in GaAs persists even at very short Mn-Mn spatial separations. The
resilience of the Mn-acceptor wave-function to high doping levels suggests that
ferromagnetism in GaMnAs is strongly influenced by impurity-band formation. The
envelope-function and tight-binding models predict similarly anisotropic
overlaps of the Mn wave-functions for Mn-Mn pairs. This anisotropy implies
differing Curie temperatures for Mn -doped layers grown on differently
oriented substrates.Comment: 4 pages, 4 figure
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