214 research outputs found
The Impact of Orthopaedic Surgery on The Quality of Life of Haemophilia Patients With or Without Inhibitors: A Systematic Review of The Literature
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Chromium(VI) reduction by ascorbate: role of reactive intermediates in DNA damage in vitro.
Reaction of chromium(VI) with one equivalent of ascorbate was studied by electron paramagnetic resonance spectroscopy in the presence of 0.10 M 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) at room temperature in 0.10 M (N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid]) (HEPES) and 0.05 M tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffers (pH 7.0 room temperature). Chromium(V), ascorbyl radical, and carbon-based DMPO-radical adducts were observed. A higher level of Cr(V) was observed in HEPES buffer and a higher level of the DMPO-radical adducts was observed in Tris-HCl buffer. Chromium-DNA binding studies were carried out in vitro for calf thymus DNA incubated with Cr(VI) and ascorbate in both buffers at 37 degrees C. Higher Cr-DNA binding was observed in HEPES buffer. DNA strand-break studies were carried out in vitro on pBR322 DNA incubated with Cr(VI) and ascorbate in both buffers at 37 degrees C. Higher percent nicking was observed in Tris-HCl buffer. Addition of DMPO decreased nicking levels in Tris-HCl buffer. These results suggest that free radicals are more reactive than Cr(V) in producing DNA strand breaks and that Cr(V) will react with DNA to produce Cr-DNA adducts. The fact that buffer affects the nature of the reactive intermediates produced upon reduction of Cr(VI) may be related to differences in intracellular metabolism of Cr(VI) and resulting DNA damage observed in various cell culture systems and animal tissues in vivo
Assessment of the Sabellaria alveolata reefs’ structural features along the Southern coast of Sicily (Strait of Sicily, Mediterranean Sea)
The honeycomb worm Sabellaria alveolata is a gregarious tube-dwelling polychaete that builds remarkable biogenic reefs in
marine coastal waters. Sabellaria alveolata reefs are considered valuable marine habitats requiring protection measures for their
conservation, as they play a key role in the functioning of coastal ecosystems. Sabellarid reefs are extensively developed along the
Atlantic coasts of Europe and reported for the Mediterranean Sea and the Italian coasts, where large reefs have been recorded in
several localities. Fragmentary information is available on their health status, Sabellaria reefs thus being listed as “Data Deficient”
in the Red List of Marine Habitats. To fill this knowledge gap, this study focused on the analysis of the structure of three reefs
found along the southern coast of Sicily. In particular, we aimed to assess their phases with respect to the natural cycle that characterizes
the sabellarid reefs. Reef features were analyzed both on the macroscale, based on the bioconstruction size (diameter and
thickness) and degree of fragmentation, and on the microscale, based on the measurement of worm density, opercular length and
sand porch presence. This study reveals relevant differences among reefs of the studied locations. These differences we attribute
to the temporal shift linked to the natural reef phases, albeit further analyses are needed to understand the possible effect of natural
and anthropogenic sources of variation on the Southern Sicilian reefs. In conclusion, Sabellaria reefs are a unique and persistent
habitat along the Sicilian coast requiring proper management and conservation measures
One Hundred Years of Observations of the Be Star HDE 245770 (the X-ray Binary A0535+26/V725 Tau): The End of an Active Phase
UBV observations of the X-ray binary system A0535+26/V725 Tau at the Crimean
Station of the Sternberg Astronomical Institute in 1980-1998 are presented.
Based on our and published data, we analyze the photometric history of the star
from 1898.Comment: Translated from Pis'ma Astronomicheskii Zhurnal, Vol. 26, No. 1,
2000, pp. 13-2
The pre-outburst flare of the A 0535+26 August/September 2005 outburst
We study the spectral and temporal behavior of the High Mass X-ray Binary A
0535+26 during a `pre-outburst flare' which took place ~5 d before the peak of
a normal (type I) outburst in August/September 2005. We compare the studied
behavior with that observed during the outburst. We analyse RXTE observations
that monitored A 0535+26 during the outburst. We complete spectral and timing
analyses of the data. We study the evolution of the pulse period, present
energy-dependent pulse profiles both at the initial pre-outburst flare and
close to outburst maximum, and measure how the cyclotron resonance-scattering
feature (hereafter CRSF) evolves. We present three main results: a constant
period P=103.3960(5)s is measured until periastron passage, followed by a
spin-up with a decreasing period derivative of Pdot=(-1.69+/-0.04)x10^(-8)s/s
at MJD 53618, and P remains constant again at the end of the main outburst. The
spin-up provides evidence for the existence of an accretion disk during the
normal outburst. We measure a CRSF energy of Ecyc~50kev during the pre-outburst
flare, and Ecyc~46kev during the main outburst. The pulse shape, which varies
significantly during both pre-outburst flare and main outburst, evolves
strongly with photon energy.Comment: 4 pages, 4 figures, accepted for publication in A&A Letters. To be
published in parallel to Postnov et al. 200
High-dispersion spectroscopic monitoring of the Be/X-ray binary A0535+26/V725 Tau I: The long-term profile variability
We report on optical high-dispersion spectroscopic monitoring observations of
the Be/X-ray binary A0535+26/V725 Tau, carried out from November 2005 to March
2009. The main aim of these monitoring observations is to study spectral
variabilities in the Be disc, on both the short (a week or so) and long (more
than hundreds of days) timescales, by taking long-term frequent observations.
Our four-year spectroscopic observations indicate that the V/R ratio, i.e., the
relative intensity of the violet (V) peak to the red (R) one, of the
double-peaked H-alpha line profile varies with a period of 500 days. The H-beta
line profile also varies in phase with the H-alpha profile. With these
observations covering two full cycles of the V/R variability, we reconstruct
the 2-D structure of the Be disc by applying the Doppler tomography method to
the H-alpha and H-beta emission line profiles, using a rigidly rotating frame
with the V/R variability period. The resulting disc structure reveals
non-axisymmetric features, which can be explained by a one-armed perturbation
in the Be disc. It is the first time that an eccentric disc structure is
directly detected by using a method other than the interferometric one.Comment: (10 pages, 9 figures, accepted to MNRAS
Alien species in the Mediterranean Sea by 2012. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part 2. Introduction trends and pathways
First record of the alien polychaete Naineris setosa (Scolecida; Orbiniidae) in Tyrrhenian Sea (Western Mediterranean)
Alien species in the Mediterranean Sea by 2012. A contribution to the application of European Union's Marine Strategy Framework Directive (MSFD). Part 2. Introduction trends and pathways
More than 60 marine non-indigenous species (NIS) have been removed from previous lists and 84 species have been added, bringing the total to 986 alien species in the Mediterranean [775 in the eastern Mediterranean (EMED), 249 in the central Mediterranean (CMED), 190 in the Adriatic Sea (ADRIA) and 308 in the western Mediterranean (WMED)]. There were 48 new entries since 2011 which can be interpreted as approximately one new entry every two weeks. The number of alien species continues to increase, by 2-3 species per year for macrophytes, molluscs and polychaetes, 3-4 species per year for crustaceans, and 6 species per year for fish. The dominant group among alien species is molluscs (with 215 species), followed by crustaceans (159) and polychaetes (132). Macrophytes are the leading group of NIS in the ADRIA and the WMED, reaching 26-30% of all aliens, whereas in the EMED they barely constitute 10% of the introductions. In the EMED, molluscs are the most species-rich group, followed by crustaceans, fish and polychaetes. More than half (54%) of the marine alien species in the Mediterranean were probably introduced by corridors (mainly Suez). Shipping is blamed directly for the introduction of only 12 species, whereas it is assumed to be the most likely pathway of introduction (via ballasts or fouling) of another 300 species. For approximately 100 species shipping is a probable pathway along with the Suez Canal and/or aquaculture. Approximately 20 species have been introduced with certainty via aquaculture, while >50 species (mostly macroalgae), occurring in the vicinity of oyster farms, are assumed to be introduced accidentally as contaminants of imported species. A total of 18 species are assumed to have been introduced by the aquarium trade. Lessepsian species decline westwards, while the reverse pattern is evident for ship-mediated species and for those introduced with aquaculture. There is an increasing trend in new introductions via the Suez Canal and via shipping.The research leading to these results was partly supported by funding from the European Community’s Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n° 287600 - PERSEUS project (Policy-oriented marine Environmental Research for the Southern European Seas). MAMIAS has been developed for the Regional Activity Centre for Specially Protected Areas of the UNEP/ Mediterranean Action Plan under contracts No 67, 68, 69, 70 and 71 /2011/RAC/RPA
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