Search results for " Stan"
showing 10 items of 1695 documents
Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutic…
2007
[EN] The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil…
Vēsture: Latvijas Universitātes Žurnāls, Nr.11/12
2021
Ferromagnetic gyroscopes for tests of fundamental physics
2020
A ferromagnetic gyroscope (FG) is a ferromagnet whose angular momentum is dominated by electron spin polarization and that will precess under the action of an external torque, such as that due to a magnetic field. Here we model and analyze FG dynamics and sensitivity, focusing on practical schemes for experimental realization. In the case of a freely floating FG, we model the transition from dynamics dominated by libration in relatively high externally applied magnetic fields, to those dominated by precession at relatively low applied fields. Measurement of the libration frequency enables in situ measurement of the magnetic field and a technique to reduce the field below the threshold for w…
Determination of low-molecular-mass aliphatic carboxylic acids and inorganic anions from kraft black liquors by ion chromatography.
2007
An ion chromatographic (IC) method with suppressed conductivity detection (CD) was developed and validated for the quantitative determination of several low-molecular-mass aliphatic mono- and dicarboxylic acids as their carboxylate anions together with some inorganic anions (chloride, sulfate, and thiosulfate) from kraft black liquors. To confirm the identification of some carboxylate anions which lack commercial model substances, a qualitative IC method with suppressed electrospray ionization mass spectrometry (ESI-MS) was also developed. The separations were performed on an IonPac AS 11-HC anion-exchange column operated at 25 degrees C within 25 min by a gradient elution with aqueous pota…
Aceites esenciales: productos antimicrobianos y antioxidantes naturales en la industria agroalimentaria
2020
[ES] Los consumidores son conscientes del peligro derivado del uso de antioxidantes y antimicrobianos sintéticos en la industria agroalimentaria, demandando alternativas más seguras y ecológicas. En este estudio, se ha determinado la actividad antioxidante de aceites esenciales comerciales mediante el método DPPH y su efecto antimicrobiano frente a la bacteria Pseudomonas syringae y el hongo fitopatógeno Fusarium oxysporum a través del empleo del método estandarizado de disco. Los aceites esenciales de clavo, ajedrea, canela y orégano, así como carvacrol, mostraron la máxima actividad antioxidante, comparable a antioxidantes establecidos. El aceite esencial de gaulteria fue el más potente i…
MR-Angiographie peripherer Gefäße mit automatischer Verschiebetisch-Technik bei 1.0 T im Vergleich zur i. a. DSA
1999
PURPOSE Contrast-enhanced (CE) 3D-MR angiography of peripheral arteries was performed in 8 patients with peripheral arterial occlusive disease by applying a new tracking technique on a 1.0 T system (Magnetom Harmony, Siemens). The studies were compared with intra-arterial digital angiography as gold standard. MATERIALS AND METHODS Imaging of the distal aorta, pelvis, upper and lower limb arteries was accomplished with a Flash-3D-sequence (TR/TE = 6.2/3.2 ms) within 26 s acquisition time of each region after a single bolus of 30 ml contrast agent. Individual circulation time was determined by a test bolus before each examination. RESULTS 112 vessel segments were evaluated. MR angiography ach…
9., 15., 16. un 17. starptautiskā finanšu pārskatu standarta būtiskāko prasību un piemērošanas problēmu izpēte Latvijas Republikas apdrošināšanas sab…
2020
Maģistra darba mērķis ir izstrādāt priekšlikumus 9., 15., 16. un 17. SFPS piemērošanas problēmu risināšanai apdrošināšanas sabiedrībās Latvijā. 2018. un 2019. gadā tika ieviesti trīs jauni SFPS, kas ietekmēja apdrošināšanas sabiedrību finanšu pārskatus. 2023. gadā plānots ieviest 17. SFPS, kas būtiski mainīs līdzšinējo apdrošināšanas līgumu uzskaiti. Līdz ar jaunu SFPS ieviešanu var rasties problēmas, kuras var novērst veicot atbilstošas darbības. Maģistra darbā tiek apskatīta SFPS būtība, apdrošināšanas tirgus darbība un stāvoklis Latvijā, kā arī 9., 15., 16. un 17. SFPS ieviešanas problēmas. Maģistra darba nobeigumā izveidoti secinājumi un priekšlikumi 9., 15., 16. un 17. SFPS ieviešanas …
Comparison of two different devices to assess intraocular lenses
2016
[EN] In this paper, we have compared the performance of two commercial systems, Kaleo-I and IOLA Plus, in the characterization of monofocal intraocular lenses (IOLs) according to the International Standard requirements (ISO 11979-2). The dioptric power (DP) and the Modulation Transfer Function (MTF) at 100.1p/mm and 3.0 mm aperture have been measured with both instruments in twenty commercial monofocal HEMA IOLs and their agreement was assessed by Bland Altman analysis. Compared with the designed power, IOLA Plus gave lower values in 85% of measures: Kaleo I errors are dependent on the power of the lens: measurements were higher than the designed power in the low-medium power range and lowe…
Identifying the Unknown Content of an Ancient Egyptian Sealed Alabaster Vase from Kha and Merit’s Tomb Using Multiple Techniques and Multicomponent S…
2020
This article highlights the multianalytical study of exuded liquid from an ancient Egyptian sealed alabaster vase by Master's students in an applied chemistry for cultural heritage course. Master students are introduced to the field of Archaeometry that see the collaboration of experts in different areas of research such as conservators, curators of museums, physicists, chemists, etc. The sample is a residue exuded on the linen strip sealing an ancient Egyptian alabaster vase (inventory number S.8448) from the collection of the Museo Egizio in Turin (Italy). The students start to plan the noninvasive investigation by X-ray fluorescence (XRF), transmission electron microscopy (TEM), and ener…
Conflicting needs of the thermal indoor environment of museums: In search of a practical compromise
2008
Thermal indoor microclimate conditions in museum buildings refer to two important requirements: the preservation of works of art and the comfort of visitors to these buildings and/or those working inside them. Unfortunately, different works of art have different internal parameters which render the management and control of the indoor thermal microclimate difficult. In this work the values proposed by various standards for the thermal environment of museum buildings have been revised. Moreover, the indoor microclimatic conditions relating to people's comfort have been described, with the aim of singling out possible common ranges for these parameters. With this aim, a useful simultaneousnes…