517 research outputs found
1005-81 Myocardial Protection by Na+/H+ Exchange Inhibition in Ischemic, Reperfused Porcine Hearts
The protective effect of the Na+/H+ exchange inhibitor HOE 694 was tested in porcine hearts subjected to 45min of regional ischemia and 24 h of reperfusion. The compound (3mg/kg) was intravenously injected in 6 pigs each either 10 min before ischemia (group A) or 10 min before reperfusion (group B). Six animals served as controls. Apart from the main end-points, infarct size and regional systolic shortening, the effect of HOE 694 on global hemodynamic parameters which included coronary blood flow and coronary venous oxygen saturation was evaluated. Although the Na+IH+ exchange inhibitor did not affect global hemodynamics, preischemic treatment with HOE 694 decreased infarct size from 65±18% (control group) to 12 ± 9% (p < 0.01) and improved systolic shortening from 8 ± 6% (control group) to 28 ± 9% P < 0.02). In addition, increase in heart rate and myocardial contracture during early reperfusion were significantly attenuated in group A. Treatment of group B did not exhibit protective effects.ConclusionNa+/H+ exchange inhibition is a very protective means in myocardial ischemia and reperfusion when administered before ischemia. In this model, it was ineffective when given before reperfusion
Степень и глубина наклепа поверхности отверстия при глубоком сверлении твердосплавными сверлами одностороннего резания
A comprehensive set of experimental and analytical methods has been used to characterise the sealing and fluid -transport properties of fine-grained (pelitic) sedimentary rocks under the pressure and temperature conditions of geological CO2 storage. The flow experiments were carried out on cylindrical sample plugs of 28.5 or 38 mm diameter and 10-20 mm length. The capillary sealing effici ncy of the lithotypes was determined by repetitive gas breakthrough experiments to test for reproducibility and to detect petrophysical changes of the rock samples resulting from CO2/water/rock interactions. These tests were performed with both, Helium and sc CO2 on the initially water-saturated sample plugs. Although molecular diffusion is not considered as an efficient leakage mechanism it represents a rate-determining step in mineral reactions and reactive transport. Therefore repetitive CO2 diffusion experiments were carried out on selected samples in the water-saturated state. These measurements provide information on the molecular mobility of CO2 and its hydrolysis products and on the physical and chemical storage capacity of the rock for these species. Before and after each experiment a steady -state fluid flow of water was established across the samples by applying high pressure gradients. This procedure ensured a defined state of saturation. Permeability coefficients derived from these tests were used to detect changes in the transport properties resulting from exposure to CO2. The fluid transport experiments were complemented by petrophysical (BET specific surface area, mercury porosimetry) and mineralogical analyses (X-ray diffraction; XRD ) of the original and post -experiment samples. The experiments revealed significant changes in the transport properties and the sealing efficiency of the samples. The gas breakthrough tests resulted in reduced capillary entry pressures and increased effective gas permeability as a result of repetitive exposure to CO2. Repeated diffusion tests revealed a faster diffusive transport in the second experiment. An increase in water permeability was consistently observed after both, capillary breakthrough tests and diffusi on experiments with CO2. The BET and mercury porosimetry results were not significantly affected by the CO2 treatment. XRD measurements before and after CO2 treatment revealed significant variations in the mineral compositions of the samples upon exposure to CO2. © 2009 Elsevier Ltd. All rights reserved
The axial charge of the nucleon on the lattice and in chiral perturbation theory
We present recent Monte Carlo data for the axial charge of the nucleon
obtained by the QCDSF-UKQCD collaboration for N_f=2 dynamical quarks. We
compare them with formulae from chiral perturbation theory in finite and
infinite volume and find a remarkably consistent picture.Comment: 6 pages, 3 figures, talk presented at Lattice2005 (weak matrix
elements), needs PoS.cl
Ecotoxicological evaluation of surface waters in Northern Namibia
The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them
PET/CT Respiratory Motion Correction With a Single Attenuation Map Using NAC Derived Deformation Fields
Respiratory motion correction is beneficial in positron emission tomography. Different strategies for handling attenuation correction in conjunction with motion correction exist. In clinical practice, usually a single attenuation map is available, derived from computed tomography in one respiratory state. This can introduce an unwanted bias (through misaligned anatomy) into the motion correction algorithm. This paper builds upon previous work which suggested that non-attenuation corrected data was suitable for motion estimation, through the use of motion models, if time-of-flight data are available. Here, the previous work is expanded upon by incorporating attenuation correction in an iterative process. Non-attenuation corrected volumes are reconstructed using ordered subset expectation maximisation and used as input for motion model estimation. A single attenuation map is then warped to the volumes, using the motion model, the volumes are attenuation corrected, after which another motion estimation and correction cycle is performed. For validation, 4-Dimensional Extended Cardiac Torso simulations are used, for one bed position, with a field of view including the base of the lungs and the diaphragm. The output from the proposed method is evaluated against a non-motion corrected reconstruction of the same data visually, using a profile as well as standardised uptake value analysis. Results indicate that motion correction of inter-respiratory cycle motion is possible with this method, while accounting for attenuation deformatio
A revision of Cyanonectria and Geejayessia gen. nov., and related species with Fusarium-like anamorphs
A revision of Fusarium-like species associated with the plant
genus Buxus led to a reconsideration of generic concepts in the
Fusarium clade of the Nectriaceae. Phylogenetic analyses of
the partial second largest subunit of the RNA polymerase II (rpb2)
and the larger subunit of the ATP citrate lyase (acl1) gene exons
confirm the existence of a clade, here called the terminal Fusarium
clade, that includes genera such as Fusarium sensu stricto
(including its Gibberella teleomorphs), Albonectria,
Cyanonectria, “Haematonectria”, the newly
described genus Geejayessia, and “Nectria”
albida. Geejayessia accommodates five species. Four were
previously classified in Nectria sensu lato, namely the black
perithecial, KOH–species G. atrofusca and the orange or
reddish, KOH+ G. cicatricum, G. desmazieri and G.
zealandica. Geejayessia celtidicola is newly described.
Following our phylogenetic analyses showing its close relationship with
Cyanonectria cyanostoma, the former Gibbera buxi is
recombined as the second species of Cyanonectria. A three gene
phylogenetic analysis of multiple strains of each morphological species using
translation elongation factor 1 α (tef-1), rpb2 and
acl1 gene exons and introns confirms their status as distinct
phylogenetic species. Internal transcribed spacer of the ribosomal RNA gene
cluster and nuclear large ribosomal subunit sequences were generated as
additional DNA barcodes for selected strains. The connection of Fusarium
buxicola, often erroneously reported as the anamorph of G.
desmazieri, with the bluish black and KOH+ perithecial species C.
buxi is reinstated. Most Cyanonectria and Geejayessia
species exhibit restricted host ranges on branches or twigs of Buxus
species, Celtis occidentalis, or Staphylea
trifolia. Their perithecia form caespitose clusters on
well-developed, mostly erumpent stromata on the bark or outer cortex of the
host and are relatively thin-walled, mostly smooth, and therefore reminiscent
of the more or less astromatous, singly occurring perithecia of
Cosmospora, Dialonectria, and Microcera. The cell walls in
outer- and inner layers of the perithecial walls of Cyanonectria and
Geejayessia have inconspicuous pore-like structures, as do
representative species of Albonectria, Fusarium sensu stricto,
“Haematonectria”, and “Nectria”
albida. The taxonomic significance of these structures, which we call
Samuels' pores, is discussed
An overview of the taxonomy, phylogeny, and typification of nectriaceous fungi in Cosmospora, Acremonium, Fusarium, Stilbella, and Volutella
A comprehensive phylogenetic reassessment of the ascomycete genus
Cosmospora (Hypocreales, Nectriaceae) is undertaken using
fresh isolates and historical strains, sequences of two protein encoding
genes, the second largest subunit of RNA polymerase II (rpb2), and a
new phylogenetic marker, the larger subunit of ATP citrate lyase
(acl1). The result is an extensive revision of taxonomic concepts,
typification, and nomenclatural details of many anamorph- and
teleomorph-typified genera of the Nectriaceae, most notably
Cosmospora and Fusarium. The combined phylogenetic analysis
shows that the present concept of Fusarium is not monophyletic and
that the genus divides into two large groups, one basal in the family, the
other terminal, separated by a large group of species classified in genera
such as Calonectria, Neonectria, and Volutella. All accepted
genera received high statistical support in the phylogenetic analyses.
Preliminary polythetic morphological descriptions are presented for each
genus, providing details of perithecia, micro- and/or macro-conidial
synanamorphs, cultural characters, and ecological traits. Eight species are
included in our restricted concept of Cosmospora, two of which have
previously documented teleomorphs and all of which have
Acremonium-like microconidial anamorphs. A key is provided to the
three anamorphic species recognised in Atractium, which is removed
from synonymy with Fusarium and epitypified for two macroconidial
synnematous species and one sporodochial species associated with waterlogged
wood. Dialonectria is recognised as distinct from Cosmospora
and two species with teleomorph, macroconidia and microconidia are accepted,
including the new species D. ullevolea. Seven species, one with a
known teleomorph, are classified in Fusicolla, formerly considered a
synonym of Fusarium including members of the F. aquaeductuum
and F. merismoides species complex, with several former varieties
raised to species rank. Originally a section of Nectria,
Macroconia is raised to generic rank for five species, all producing
a teleomorph and macroconidial anamorph. A new species of the
Verticillium-like anamorphic genus Mariannaea is described
as M. samuelsii. Microcera is recognised as distinct from
Fusarium and a key is included for four macroconidial species, that
are usually parasites of scale insects, two of them with teleomorphs. The four
accepted species of Stylonectria each produce a teleomorph and micro-
and macroconidial synanamorphs. The Volutella species sampled fall
into three clades. Pseudonectria is accepted for a perithecial and
sporodochial species that occurs on Buxus. Volutella s. str.
also includes perithecial and/or sporodochial species and is revised to
include a synnematous species formerly included in Stilbella. The
third Volutella-like clade remains unnamed. All fungi in this paper
are named using a single name system that gives priority to the oldest generic
names and species epithets, irrespective of whether they are originally based
on anamorph or teleomorph structures. The rationale behind this is
discussed
Chemical analysis of Greek pollen - Antioxidant, antimicrobial and proteasome activation properties
<p>Abstract</p> <p>Background</p> <p>Pollen is a bee-product known for its medical properties from ancient times. In our days is increasingly used as health food supplement and especially as a tonic primarily with appeal to the elderly to ameliorate the effects of ageing. In order to evaluate the chemical composition and the biological activity of Greek pollen which has never been studied before, one sample with identified botanical origin from sixteen different common plant taxa of Greece has been evaluated.</p> <p>Results</p> <p>Three different extracts of the studied sample of Greek pollen, have been tested, in whether could induce proteasome activities in human fibroblasts. The water extract was found to induce a highly proteasome activity, showing interesting antioxidant properties. Due to this activity the aqueous extract was further subjected to chemical analysis and seven flavonoids have been isolated and identified by modern spectral means. From the methanolic extract, sugars, lipid acids, phenolic acids and their esters have been also identified, which mainly participate to the biosynthetic pathway of pollen phenolics. The total phenolics were estimated with the Folin-Ciocalteau reagent and the total antioxidant activity was determined by the DPPH method while the extracts and the isolated compounds were also tested for their antimicrobial activity by the dilution technique.</p> <p>Conclusions</p> <p>The Greek pollen is rich in flavonoids and phenolic acids which indicate the observed free radical scavenging activity, the effects of pollen on human fibroblasts and the interesting antimicrobial profile.</p
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