A new class of pulsating subdwarf B stars has recently been announced by Green and coworkers. Here we present a follow-up paper describing our observations and the pulsation structure of the class ...prototype PG 1716+426. The oscillations are multiperiodic with periods between 0.8 and 1.4 hr (180-340 mu Hz) and semiamplitudes less than 0.2%. We also observe that the periods and amplitudes appear variable, making the pulsation structure of PG 1716 complicated. The periods are an order of magnitude longer than those seen in EC 14026 (sdBV) stars, implying that they are gravity modes rather than pressure modes. As such, they represent a new class of variable star.
The conformational of selected 1-(2-pyrimidinyl)piperazine derivatives with high sedative-hypnotic activity was analysed and the model bioactive conformations were suggested. Subsequently, the ...pharmacophores of analysed compounds were designed. It was suggested that the pharmacophore of bioactive derivatives should be composed of 11 features that characterise the binding model of pyrimidinylpiperazine ligands to the binding site at the hypothetic receptor. This 11 feature pharmacophore was compared to three other pharmacophores designed for the selected anxiolytics (benzodiazepines and buspirone analogues) and the sedative-hypnotic agents (benzodiazepines and barbiturates). Several substantial differences between the pharmacophores were found: the number of pharmacophoric features and their distribution in 3-D space were unique for selected groups of compounds that exhibit sedative-hypnotic or anxiolytic activity.
Application of enzymatic catalysis in chemical analysis enables increase of selectivity, reduction of detection limits, lowering of analysis costs and duration. Enzymes in flow through analytical ...systems can be applied in two main configurations 1. In the first of them, enzymes are immobilized on special carriers in flow-through reactor. The second possible configuration are biosensors (working as detectors), in which enzyme molecules are an integral part of sensor receptor layer. In both cases, enzyme immobilization is necessary to ensure multiple use of applied system.
In presented work the possibility of application of novel fluoride selective electrodes, as detector in FIA systems utilizing enzymatic reactions in various configurations has been evaluated. Different methods of enzyme (Acid Phosphatase, EC 3.1.3.2) immobilization have been tested, including covalent bonding via -NH2 and -COOH groups (both on ion exchanger resin and sensor membrane) and cross linking with glutaraldehyde (CLEAs, cross linked enzyme aggregates).
Modern concepts of buspirone activity as an anxiolytic drug are reviewed. Particular attention is focused on the molecular aspects of buspirone interactions in the phases that simulate cellular ...environment. Three-dimensional models of buspirone-serotonin receptor complexes are discussed as well.
It has been shown that G-protein coupled receptors have seven transmembrane alpha-helices, but the structural changes occurring in a G-protein coupled receptor as a response on agonist stimulus and ...the molecular events leading to blockade of the signal transduction by antagonists are not well understood. In the present study, the AMBER 5.0 force field was used for comparative molecular dynamics simulations of a 5-HT(1A) receptor model in the absence of ligand, in complex with a 5-HT(1A) receptor agonist (R)-8-hydroxy-2-(di-n-propylamino)tetralin (R)-8-OH-DPAT, in complex with a selective 5-HT(1A) receptor antagonist (S)-N-tert-butyl-3-4-(2-methoxyphenyl)piperazin-1-yl -2-phenylpropanamide (S)-WAY100135, and in complex with the partial agonist, buspirone. In the simulations, the agonist induced larger conformational changes into transmembrane helix 3 and 6 than into the other helices, while the main conformational differences between the agonist bound receptor and the antagonist bound receptor were in transmembrane helix 5 and 6. During the simulations, all the three ligands constrained the helical movements compared to those observed in the receptor without any ligand.
Three-dimensional (3-D) models of the human serotonin 5-HT1A and 5-HT2A receptors were constructed, energy refined, and used to study the interactions with a series of buspirone analogues. For both ...receptors, the calculations showed that the main interactions of the ligand imide moieties were with amino acids in transmembrane helix (TMH) 2 and 7, while the main interactions of the ligand aromatic moieties were with amino acids in TMH5, 6 and 7. Differences in binding site architecture in the region of highly conserved serine and tyrosine residues in TMH7 gave slightly different binding modes of the buspirone analogues at the 5-HT1A and 5-HT2A receptors. Molecular dynamics simulations of receptor-ligand interactions indicated that the buspirone analogues did not alter the interhelical hydrogen bonding patterns upon binding to the 5-HT2A receptor, while interhelical hydrogen bonds were broken and others were formed upon ligand binding to the 5-HT1A receptor. The ligand-induced changes in interhelical hydrogen bonding patterns of the 5-HT1A receptor were followed by rigid body movements of TMH2, 4 and 6 relative to each other and to the other TMHs, which may reflect the structural conversion into an active receptor structure.
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PG 0014+067 is one of the most promising pulsating subdwarf B stars for seismic analysis, as it has a rich pulsation spectrum. The richness of its pulsations, however, poses a fundamental challenge ...to understanding the pulsations of these stars, as the mode density is too complex to be explained only with radial and nonradial low-degree (l < 3) p-modes without rotational splittings. One proposed solution, suggested by Brassard et al. in 2001 for the case of PG 0014+067 in particular, assigns some modes with high degree (l= 3). On the other hand, theoretical models of sdB stars suggest that they may retain rapidly rotating cores, and so the high mode density may result from the presence of a few rotationally split triplet (l = 1) and quintuplet (l = 2) modes, along with radial (l = 0) p-modes. To examine alternative theoretical models for these stars, we need better frequency resolution and denser longitude coverage. Therefore, we observed this star with the Whole Earth Telescope for two weeks in 2004 October. In this paper we report the results of Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067. We find that the frequencies seen in PG 0014+067 do not appear to fit any theoretical model currently available; however, we find a simple empirical relation that is able to match all of the well-determined frequencies in this star.
The aim of the research was to investigate the impact iodine solution disinfection had on
(L.) egg survival rates during incubation, and to determine the effect of the disinfection procedure on egg ...shells using scanning microscopy. The study groups were bathed in a Desamar K30 solution at a concentration of 100 ml per 10 dm
for 10 m once after the eggs had hardened and four times after the eyed stage. Egg samples for scanning analyses were collected on day 30 of incubation at the eyed stage after the first bath in the iodophor solution, and then at the end of incubation. Egg surface images were analyzed for the number of bacteria, the presence of hyphae, and the egg surface area covered with sediments. No statistically significant differences were noted in embryo survival rates in the groups that were disinfected. The highest number of bacteria was observed on egg surfaces which had not been disinfected prior to hatching. A significant amount of sediment was observed on the eggs during incubation. On day 90 of incubation, all of the egg surfaces were covered with sediments. Disinfection was not noted to have had a significant impact on the presence of hyphae. Iodophor preparations can be used for routine disinfection of trout eggs; however, other means of disinfection should be applied before the eyed egg stage.
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