69 research outputs found
Influence of natural polyphenolic fractions on cellular respiration
We have studied the influence of two polyphenolic
fractions â methanolic (PMF) and ethanolic (PEF) â extracted from the
leaves of the medicinal plant Asclepias syriaca upon cellular respiration.
Experiments were performed in vitro on the cells from liver, sartorius
striated muscle and stomach smooth muscle of frog (Rana ridibunda, Pall.),
determining the cellular oxygen consumption by the Warburg
micromanometric method. Polyphenol effects were different, depending on
the nature of used fraction and cellular type. Therefore, after 90 minutes of
experiencing on liver, the both polyphenolic fractions stimulated cellular
respiration, compared to the untreated control. The striated muscle PMF
has inhibited and PEF has stimulated respiratory processes. In stomach
muscle, reverse effects were noticed: PMF has stimulated and PEF has
slightly inhibited cellular respiration. The results pointed out the specific
action of these polyphenolic agents on cellular respiration and energetic
metabolism processes, also allowing the estimate of their useful
pharmacological properties
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
Multiple Scenario Generation of Subsurface Models:Consistent Integration of Information from Geophysical and Geological Data throuh Combination of Probabilistic Inverse Problem Theory and Geostatistics
Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming \u3c4 neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in 3c 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an E\u3bd-2 spectrum in the energy range 1.0
7 1017 eV -2.5
7 1019 eV is E2 dN\u3bd/dE\u3bd < 4.4
7 10-9 GeV cm-2 s-1 sr-1, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays
EFFECT OF SOME ACTIVE CYTOSTATIC VEGETABLE EXTRACTS OF POLYPHENOLIC NATURE UPON MEMBRANE BIOELECTRICAL POTENTIAL
Cellular effects of some bioactive principles from red wines and must
The in vitro action of some samples of red wine and concentrated must on the liver and striated muscle of frog
(Rana ridibunda, Pall) was studied, following the intensity of cellular respiration, and the redox potential (rH). Both wine
(1 mL/100mL physiological solution normal Ringer â NR) and must (2 mg dry matter/100mL NR) stimulate aerobe
cellular respiration (mm3 O2/g wet tissue) and diminish the redox potential values, comparatively with the non-treated
reference sample. Also, on treating liver and muscle cells with ethanol (1 mL/100mL NR) an evident depression of
cellular respiration and increase of redox potential values may be noticed, alongwith perturbation of cellular metabolic
processes. The obtained results evidence possible energizing, hepatoprotecting and redox modulating properties of the
bioactive principles from red wine and must
Zinc-Induced Genotoxic Effects in Root Meristems of Barley Seedlings
The pollution increase, as a result of the release into environment of genotoxic chemicals, including heavy metals, largely affects the ecosystems and the health of living organisms. Although zinc is not considered highly phytotoxic, its excess becomes noxious. In literature, the reports on zinc genotoxicity are equivocal. Therefore, the objective of this work was to evaluate the amplitude of cytogenetic damage induced in Hordeum vulgare L. cv. âMadalinâ after seed treatment with different concentrations (10, 100, 250, 500 ÎŒM) of Zn+2, provided as zinc sulphate and zinc acetate. The mitostimulatory effect was present at all concentrations of both zinc compounds. The rate of ana-telophase aberrations exceeded by 2 - 3 times the control, and the frequency of metaphase disturbances was 5.0-10.0 times higher than the control. The results indicate the clastogenic and aneugenic potential of zinc in barley and constitute a signal about the risks of its increasing presence into the environment, with repercussions on living systems, even on human health, due to the extensive use of zinc compounds including as pesticides.</p
- âŠ