210 research outputs found
Functional nitric oxide conjugate systems state/restored heart thiols of rats in modeling isadrine-pituitrin’s myocardial infarction using metabolite-tropic cardioprotector “Angiolin”
Background: According to modern researches, endothelial dysfunction (ED) is one of the primary pathogenetic elements of cardiovascular diseases (myocardial infarction [MI], ischemic heart diseases, cerebral ischemic stroke, atherosclerosis, arterial hypertension, pulmonary hypertension, heart failure, and dilated cardiomyopathy) as well as obesity, hyperlipidemia, diabetes and hyperhomocysteinemia. The aim of this work was to study the influence of potential metabolitotropic cardioprotector “Angiolin” on the parameters of conjugate systems nitric oxide (NO)/restored thiols in heart under isadrine-pituitrin MI.Methods: This study was performed on Wistar white rats weighing 190-210 g. Biochemical, immune-enzyme analysis and histoimmunechemical study were performed.Results: In histological sections of hearts of the rats receiving Angiolin in parenteral dosing 50 mg/kg 30 mins before each pituitrin injection the density of endothelial NO-synthase (NOS)-positive cells increased by 29% and the density of inducible NOS-positive cells decreased by 23.3%. In cytosolic fraction of myocardium homogenate NOS activity increased by 27%, the concentration of NO stable metabolites increased by 70% and the content of nitrosative stress marker nitrotyrosine decreased by 42% when compared with control group. At the same time in similar samples of heart homogenate the increase of restored thiol groups’ level by 53.3%, methionine - by 35.1%, cysteine - by 170% and activity of glutathione reductase - by 186% was noted. The administration of reference drug mildronate to the animals with MI in dose 100 mg/kg did not result in significant changes of the studied parameters of thiol-disulfide system and NO system of the heart when compared with control group.Conclusions: Angiolin does not influence directly on NOS in MI, but at the same time protects NO from nitrosative stress increasing restored equivalents of thiol-disulfide system
The hydrological response of Northeastern Brazil during \ud last deglaciation
Paleociimate proxy and numerical modelling data suggest prominent change in precipitation over lowland tropical South America during last deglaciation. The hydrography of Northeastem Brazil under such change in precipitation, however, remains poorly investigated. Unresolved issues relate to the possible change in sources and amounls of terrigenous input delivered to the continental slope off Northeastern Brazil. Here we analyzed a set of marine sediment cores retrieved from off the Parnaíba River Delta during research cruise MSM20/3 that provide an excellent opportunity to \ud
address these issues. Detailed radiocarbon-based age models indicate that the sedimentation rates at our core sites increased significantly from ~ 20 cm/kyr during the Last Glacial Maximum to ~70 cm/kyr during Heinrich Stadial1, and then back to ~ 20 cm/kyr during the Bolling-Allerod. One possibility for this extreme rise in sedimentation rate is the simulated reversal of the North Brazil Current and lhe supposed input of Amazonian sediment to the continental slope off the Parnaiba River Delta. Here \ud
our Nd isotopic data will help to disentangle the different sedimentary sources since the terrigenous supply from the Parnaíba and the Amazon Rivers have considerably different signatures. The ENd(O) measurement of modern sediment samples (i.e., soil, river suspended sediment load), to be collecled over Northeastem Brazil and already available marine surface and downcore results will greatly contribute to clarify possible change in the terrigenous sources. Our data shed new light into our knowledge of the coupled hydrological process (i.e., fluvial erosion and weathering) over Northeastem \ud
Brazil and its relationship with the Atlantic Meridional Oceanic Circulatio
Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory
The Pierre Auger Collaboration has reported evidence for anisotropy in the
distribution of arrival directions of the cosmic rays with energies
eV. These show a correlation with the distribution
of nearby extragalactic objects, including an apparent excess around the
direction of Centaurus A. If the particles responsible for these excesses at
are heavy nuclei with charge , the proton component of the
sources should lead to excesses in the same regions at energies . We here
report the lack of anisotropies in these directions at energies above
(for illustrative values of ). If the anisotropies
above are due to nuclei with charge , and under reasonable
assumptions about the acceleration process, these observations imply stringent
constraints on the allowed proton fraction at the lower energies
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
Offspring Hormones Reflect the Maternal Prenatal Social Environment: Potential for Foetal Programming?
Females of many species adaptively program their offspring to predictable environmental conditions, a process that is often mediated by hormones. Laboratory studies have shown, for instance, that social density affects levels of maternal cortisol and testosterone, leading to fitness-relevant changes in offspring physiology and behaviour. However, the effects of social density remain poorly understood in natural populations due to the difficulty of disentangling confounding influences such as climatic variation and food availability. Colonially breeding marine mammals offer a unique opportunity to study maternal effects in response to variable colony densities under similar ecological conditions. We therefore quantified maternal and offspring hormone levels in 84 Antarctic fur seals (Arctocephalus gazella) from two closely neighbouring colonies of contrasting density. Hair samples were used as they integrate hormone levels over several weeks or months and therefore represent in utero conditions during foetal development. We found significantly higher levels of cortisol and testosterone (both P < 0.001) in mothers from the high density colony, reflecting a more stressful and competitive environment. In addition, offspring testosterone showed a significant positive correlation with maternal cortisol (P < 0.05). Although further work is needed to elucidate the potential consequences for offspring fitness, these findings raise the intriguing possibility that adaptive foetal programming might occur in fur seals in response to the maternal social environment. They also lend support to the idea that hormonally mediated maternal effects may depend more strongly on the maternal regulation of androgen rather than cortisol levels
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