117 research outputs found
Quantitative determination of diterpene acids in garden sage leaves
© 2017, Pleiades Publishing, Ltd. A procedure is developed for the quantitative determination of diterpene acids in garden sage leaves by UV spectrophotometry at the wavelength 285 nm. The target group of compounds was selectively extracted by petroleum ether 40/70. It was shown that the completeness of extraction is determined mainly by the number of portions of the pure solvent: at the optimum ratio of the mass of the weighed portion to the volume of solvent 1 g/200 mL, double extraction is sufficient. The duration of each extraction is 20 min. The procedure was used in the analysis of samples of garden sage leaves from various producers. It was found that the concentration of diterpene acids in samples varied from 2.1 to 3.6 wt % (in terms of carnosic acid). The error of a single determination of the sum of diterpene acids in garden sage leaves is ±2.38% (P = 0.95)
Kinetics of bioactive compounds extraction from plant material using boiling solvent
© 2015, Pleiades Publishing, Ltd. A model of extracting the natural products through boiling ground plant material in a solvent using a bain-marie is proposed. The model trait is that it has only one adaptation parameter, i.e., the diffusion coefficient of the solute in the plant material, which depends on the solvent and plant material properties. The model is applied to study the kinetics of extraction, and the minimal solvent volume, which is used for extraction, is theoretically determined. A comparison of the model with the experimental data of the extraction of hydrophobic diterpene acids from sage leaves and hydrophilic flavonoids from common knotgrass herb is in good agreement with the experiment. Experiments performed with finely ground plant material (particle diameter is less than 1 mm) show that, for most extraction conditions, more than 90% of the target compounds are extracted by the time the solvent starts to boil
Forward and inverse problems of supercritical extraction of oil from polydisperse packed bed of ground plant material
The problem of determining the overall extraction curve for the supercritical fluid oil extraction from polydisperse layer of ground oilseed granules was solved analytically using the shrinking core model. The functional dependence obtained for bi-disperse approximation of the packed bed describes the results of known experiments with high accuracy. Ways to solve the inverse problem of determining the size distribution function for particles of granular layer based on experimental overall extraction curves are discussed. © 2014 Pleiades Publishing, Ltd
DANSSino: a pilot version of the DANSS neutrino detector
DANSSino is a reduced pilot version of a solid-state detector of reactor
antineutrinos (to be created within the DANSS project and installed under the
industrial 3 GW(th) reactor of the Kalinin Nuclear Power Plant -- KNPP).
Numerous tests performed at a distance of 11 m from the reactor core
demonstrate operability of the chosen design and reveal the main sources of the
background. In spite of its small size (20x20x100 ccm), the pilot detector
turned out to be quite sensitive to reactor antineutrinos, detecting about 70
IBD events per day with the signal-to-background ratio about unity.Comment: 16 pages, 11 figures, 3 tables. arXiv admin note: substantial text
overlap with arXiv:1304.369
Measurement of the double- β decay of <sup>150</sup> Nd to the 0 1+ excited state of <sup>150</sup> Sm in NEMO-3
The NEMO-3 results for the double- β decay of 150 Nd to the 0 1+ and 2 1+ excited states of 150 Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope 150 Nd are used in the analysis. The signal of the 2 νββ transition to the 0 1+ excited state is detected with a statistical significance exceeding 5 σ . The half-life is measured to be T1/22νββ(01+)=[1.11-0.14+0.19(stat)-0.15+0.17(syst)]×1020 year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the 2 νββ decay to the 2 1+ level the limit is T1/22νββ(21+)>2.42×1020year . The limits on the 0 νββ decay to the 0 1+ and 2 1+ levels of 150 Sm are significantly improved to T1/20νββ(01+)>1.36×1022year and T1/20νββ(21+)>1.26×1022year
Measurement of the intrinsic hadronic contamination in the NA64−e high-e+/e- purity beam at CERN
We present the measurement of the intrinsic hadronic contamination at the CERN SPS H4 beamline configured to transport electrons and positrons at 100 GeV/c. The analysis, performed using data collected by the NA64-e experiment in 2022, is based on calorimetric measurements, exploiting the different interaction mechanisms of electrons and hadrons in the NA64 detector. We determined the contamination by comparing the results obtained using the nominal electron/positron beamline configuration with those from a dedicated setup, in which only hadrons impinged on the detector. We also obtained an estimate of the relative protons, anti-protons and pions yield by exploiting the different absorption probabilities of these particles in matter. We cross-checked our results with a dedicated Monte Carlo simulation for the hadron production at the primary T2 target, finding a good agreement with the experimental measurements
Usage of the Hoyer's medium for diagnostics and morphological studies of some parasites
Various modification of the mixture of gum arabic with chloral hydrate can be used for mounting of small arthropods as well as some helminths. However, in diagnostic laboratories in Poland they seem to remain unknown. The authors of current work present examples of the Hoyer’s medium application. The medium has been composed according to the initial, given by Hoyer, hundred-years-old recipe, which was the root of all other, later used recipes. Hoyer’s medium is universal in action and very comfortable to use in slides for microscope investigation. It gives the immediate light-through effect, so it can be helpful in fast diagnostics. At the same time it allows to store the slides for a relatively long time e.g. with education purpose
Forward and inverse problems of supercritical extraction of oil from polydisperse packed bed of ground plant material
The problem of determining the overall extraction curve for the supercritical fluid oil extraction from polydisperse layer of ground oilseed granules was solved analytically using the shrinking core model. The functional dependence obtained for bi-disperse approximation of the packed bed describes the results of known experiments with high accuracy. Ways to solve the inverse problem of determining the size distribution function for particles of granular layer based on experimental overall extraction curves are discussed. © 2014 Pleiades Publishing, Ltd
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