58 research outputs found

    UVSat: a concept of an ultraviolet/optical photometric satellite

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    Time-series photometry from space in the ultraviolet can be presently done with only a few platforms, none of which is able to provide wide-field long-term high-cadence photometry. We present a concept of UVSat, a twin space telescope which will be capable to perform this kind of photometry, filling an observational niche. The satellite will host two telescopes, one for observations in the ultraviolet, the other for observations in the optical band. We also briefly show what science can be done with UVSat.Comment: 6 pages, 2 figures, accepted for publication in the Proceedings of the PAS (Proc. of the 2nd BRITE Science conference, Innsbruck

    Surface science of soft scorpionates

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    The chemisorption of the soft scorpionate Li[PhTmMe] onto silver and gold surfaces is reported. Surface enhanced Raman spectroscopy in combination with the Raman analysis of suitable structural models, namely, [Cu(κ3-S,S,S-PhTmMe)(PCy3)], [Ag(κ3-S,S,S-PhTmMe)(PCy3)], [Ag(κ2-S,S-PhTmMe)(PEt3)], and [Au(κ1-S-PhTmMe)(PCy3)], are employed to identify the manner in which this potentially tridentate ligand binds to these surfaces. On colloidal silver surface-enhanced Raman spectroscopy (SERS) spectra are consistent with PhTmMe binding in a didentate fashion to the surface, holding the aryl group in close proximity to the surface. In contrast, on gold colloid, we observe that the species prefers a monodentate coordination in which the aryl group is not in close proximity to the surface

    Epidemiologiczne badania nad giardioza u mieszkancow Szczecina

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    The aim of the studies was to establish the prevalence of Giardia intestinalis in Szczecin population. The studies were carried out in 1991-1996. In this period 46 584 persons - 22 371 adults and 24 213 children were examined. Faecal samples were examined with two methods - coprological and immunoenzymatic (ELISA) test. A total of 356 persons (0.78%) were found to be infected with G. intestinalis. No statistically significant differences between the infection rate of adults and children were observed. The adults were infected in 0.73% and the children in 0.80%. The analysis of the annual dynamics of G. intestinalis infection shows twice as large infection rate in September- October (1.18 %) as in the remaining months (0.66 %)

    Aktywność antyoksydacyjna herbat dostępnych na polskim rynku, otrzymywanych z liści Camellia sinensis (L.) Kuntze podczas róznych procesów produkcyjnych

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    The leaves of Camellia sinensis (L.) Kuntze are used to produce many types of tea; this variety results from the production process. The extracts, especially from teas rich in polyphenols, are also used in the prevention and treatment of certain diseases, in addition to their application for consumption. The aim of the study was to compare the antioxidant activity and total phenolic content in extracts from the following types of tea: white, green, oolong, black and Pu-erh. The aqueous and methanolic extracts from the teas were analysed by spectrophotometric methods. The method with the Folin-Ciocalteu reagent was used to determine total phenolic content; the antioxidant activity was investigated by means of the reaction with the DPPH radical. Total phenolic content and the antioxidant activity of examined extracts differed significantly. The alcoholic and aqueous extracts from white and green tea of the highest content of polyphenols (97.1–84.4 mg GAE/g) showed the greatest antioxidant activity (IC50 0.263–0.329 mg/ml), similar to that of BHA. The methanolic extracts from black and Pu-erh tea demonstrated much weaker activity. The antioxidant activity of extracts from investigated teas is closely correlated with content of polyphenolic compounds, which depends on the type of tea and the solvent used for extraction.Liście Camellia sinensis (L.) Kuntze są używane do produkcji wielu rodzajów herbat, których różnorodność wynika z procesu produkcyjnego. Wyciągi, zwłaszcza z herbat bogatych w polifenole, poza zastosowaniem spożywczym, są wykorzystywane również w profilaktyce i wspomaganiu leczenia niektórych chorób. Celem pracy było porównanie aktywności antyoksydacyjnej i zawartości sumy polifenoli w wyciągach z herbaty: białej, zielonej, oolong, czarnej i Pu-erh. Wyciągi wodne i metanolowe z herbat analizowano metodami spektrofotometrycznymi. Do oznaczenia sumy polifenoli użyto metody z odczynnikiem Folin-Ciocalteu, aktywność antyoksydacyjną badano w oparciu o reakcję z rodnikiem DPPH. Zawartość sumy polifenoli i aktywność antyoksydacyjna badanych ekstraktów znacznie się różniły. Wyciągi alkoholowe i wodne z herbaty białej i zielonej, o najwyższej zawartości polifenoli (97,1-84,4 mg GAE/ g), wykazywały też najwyższą, zbliżoną do BHA, aktywność przeciwutleniającą (IC50 0,263-0,329 mg/ml). Ekstrakty metanolowe z herbaty czarnej i Pu-erh posiadały wielokrotnie słabsze działanie. Aktywność antyoksydacyjna wyciągów z badanych herbat jest ściśle skorelowana z zawartością w nich związków polifenolowych, która zależy od rodzaju herbaty i użytego do ekstrakcji rozpuszczalnika
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