The aim of the present work was to establish the limiting factors affecting the biosynthesis of volatile esters present in virgin olive oil (VOO). Oil volatile fractions of the main Spanish olive ...cultivars, Arbequina and Picual, were analyzed. It was observed that acetate esters were the most abundant class of volatile esters in the oils, in concordance with the high content of acetyl-CoA found in olive fruit, and that the content of C6 alcohols is limited for the synthesis of volatile esters during the production of VOO. Thus, the increase of C6 alcohol availability during VOO production produced a significant increase of the corresponding ester in the oils in both cultivars at two different maturity stages. However, the increase of acetyl-CoA availability had no effect on the VOO volatile fraction. The low synthesis of these C6 alcohols seems not to be due to a shortage of precursors or cofactors for alcohol dehydrogenase (ADH) activity because their increase during VOO production had no effect on the C6 alcohol levels. The experimental findings are compatible with a deactivation of ADH activity during olive oil production in the cultivars under study. In this sense, a strong inhibition of olive ADH activity by compounds present in the different tissues of olive fruit has been observed.
The roots of
Chiococca alba have been employed to treat rheumatic disorders and for other therapeutic purposes in Brazil and elsewhere. This study was undertaken to evaluate the toxicological ...properties of an ethanolic extract from
Chiococca alba roots (EE), including mutagenicity in the
Salmonella assay and acute and subacute toxicity to mice. Single oral doses of EE caused hypoactivity, but no deaths were noted up to the highest dose tested (2000
mg/kg). EE (500
mg/kg p.o.) reduced mouse locomotion in the open field test. EE was markedly more toxic when given by intraperitoneal (i.p.) and subcutaneous (s.c.) routes. Acute approximate lethal doses (ALD) were 125
mg/kg (males) and 250
mg/kg (females) and 250
mg/kg (both sexes) by i.p. and s.c. routes, respectively. Deaths after single doses were preceded by hypoactivity, ataxia and lethargy. Repeated administration of EE by gavage for 14 days caused no deaths. Activity of liver monooxygenases (pentoxy- and ethoxyresorufin-
O-dealkylases) was not altered by repeated treatment with EE (2000
mg/kg/day p.o.). Administration of EE by the i.p. route for 14 days decreased weight gain and caused anemia, neutrophilia and deaths. The no-observed-adverse-effect level (NOAEL) for subacute treatment by the i.p. route was as low as 15.6
mg of EE/kg body weight (wt)/day. EE was not mutagenic in the
Salmonella/microsome assay with TA100, TA98, TA97a and TA1535 strains. In summary, EE was not mutagenic and presented a low acute and subacute toxicity by the oral route. Toxicities by parenteral routes, however, were more pronounced.
EUSO-SPB1 mission and science Abdellaoui, G.; Adams, J.H.; Alonso, G. ...
Astroparticle physics,
January 2024, 2024-01-00, 2024, Letnik:
154
Journal Article
Recenzirano
Odprti dostop
The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure ...balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search.
Dissociation energies of protonated water clusters Wróblewski, T.; Ziemczonek, L.; Gazda, E. ...
Radiation physics and chemistry (Oxford, England : 1993),
09/2003, Letnik:
68, Številka:
1
Journal Article
Recenzirano
Relative abundances of positively ionized water clusters formed in a low-pressure electrical discharge as function of reduced electric field were obtained by using drift cell and quadrupole mass ...spectrometer. It was noticed that some clusters say with
n=4 were more abundant than others, at comparable drift conditions. Dissociation energies have been derived from equilibrium conditions for relative clusters abundances. The Hartree–Fock method in 6-311G** molecular-basis set has been applied to calculations of binding energies for different structural “families” of clusters.
The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure ...balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33~km). After 12~days and 4~hours aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of approximately 3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search.
This is a collection of papers presented by the JEM-EUSO Collaboration at the 38th International Cosmic Ray Conference (Nagoya, Japan, July 26-August 3, 2023)
Swarm experiment on ionized water clusters Wróblewski, Tomasz; Gazda, Emil; Mechlińska-Drewko, Jadwiga ...
International journal of mass spectrometry,
04/2001, Letnik:
207, Številka:
1
Journal Article
Recenzirano
Drift of positively ionized water clusters formed in a low-pressure electrical discharge was studied by mass spectroscopy. Ions H
+(H
2O)
n
with
n = 1–7 were observed at room temperature and at ...pressures in a few hundreds Pa range. Relative cluster abundances depend on the reduced electrical field in the drift chamber. The H
+(H
2O)
4 clusters are somewhat more abundant than those with
n = 3, 5. Fragmentation energies, in a rough agreement with other experimental and theoretical values, have been derived from equilibrium conditions for relative cluster abundances. Calculations of dissociation energies of cationic clusters with
n up to 7 have been performed in Hartree-Fock approximation with a 6-311∗∗G basis set.
PDF
