Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Sikora, B." wg kryterium: Autor

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-3 z 3
    Tytuł:
    Alditole i anhydroalditole
    Alditols and anhydroalditols
    Autorzy:
    Sikora, K.
    Samaszko-Fiertek, J.
    Ślusarz, R.
    Liberek, B.
    Madaj, J.
    Dmochowska, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/171690.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    alditol
    anhydroalditol
    dianhydroalditol
    Opis:
    Alditols belong to the group of acyclic polyols. Formally, they are obtained from the aldose or ketose by reduction of the carbonyl group. Single or double dehydratation of alditols provides the cyclic compounds named anhydroalditols and dianhydroalditols, respectively. Alditols and anhydroalditols are widespread in both animal and plant kingdoms. They are in human blood and urine, and in the amniotic and cerebrospinal fluids. Herein the applications of alditols and anhydroalditols in medicine and human nutrition are presented. (For example d-mannitol is used as a diuretic agent or in osmotherapy to reduce acutely raised intracranial pressure; isosorbide mononitrate is used against angina pectoris. Xylitol (pentitol) can counteract several diseases, among others, the acute otitis media, osteoporosis, tooth decay and helps the remineralization of teeth, thanks to that it found use as an additive to chewing gum [4]. Most alditols including d-mannitol, d-glucitol and 1,4-anhydro-d,l-galactitol, are used as sweeteners and as well as additives for low caloric food or as diets for diabeties. Although they show lower sweetness than glucose or saccharose, their great advantage is that it does not cause a rapid increase of glucose level in blood [5,6]. While nitrates 1,4:3,6-dianhydro-d-mannitol and 1,4:3,6-dianhydro-d-glucitol thanks to the ability of blood vessels relaxant are commonly used for years in the treatment of heart diseases and blood system [10]). It is demonstrated that introduction of alditol or anhydroalditol to biologically active compound may improve its activity. Anhydroalditols are also useful substrates for the stereospecific synthesis of bicyclic compounds. Additionally, alditols and anhydroalditols are promising monomers for synthesis of polymers with interesting properties. Finally, methods of alditols and anhydroalditols syntheses are presented. Among them we consider: cyclization in an acid medium involving intramolecular dehydration, SN2 reaction with suitable leaving groups, deamination reaction combined with reduction, reduction of glycosyl halide, tioglycoside and glycoside, and addition of water or hydrogen to the double bond in glycals.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 1-2; 65-86
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cukrowe czwartorzędowe sole amoniowe
    Sugar quaternary ammonium salts
    Autorzy:
    Dmochowska, B.
    Sikora, K.
    Samaszko-Fiertek, J.
    Ślusarz, R.
    Madaj, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/172328.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    czwartorzędowe sole amoniowe
    d-glikopiranozydy
    celuloza
    chitozan
    quaternary ammonium salts
    d-glicopyranosides
    cellulose
    chitosan
    Opis:
    Quaternary ammonium compounds (QACs) exhibit the properties of both inorganic and organic compounds, and their ionic nature gives them hydrophilic character. The popularity of these compounds is allied to their many applications and ease of synthesis. Most of QACs are stable up to 150°C, readily soluble in water, usually non-toxic in utilitarian concentrations, are surface active, and do not irritate the skin or have a noxious odour [1]. Many of them have fungicidal, bactericidal and algicidal properties [2–5]. The antiviral action of QACs, including against HIV [6, 7], has been reported. They are used as timber preservatives, disinfectants, fabric softeners, anti-electrostatic agents and antifriction substances [5, 8, 9]. In addition, certain drugs administered in cases of diabetes, cardiac arrhythmia, neuroses, allergies and even carcinomas are QACs. Finally, QACs are used in chemical synthesis as catalysts, in phase-boundary catalysis [11], in the reduction of aldehydes and alkenes, and in the Friedl-Crafts reaction. In literature there is only limited amount of information considering quaternary ammonium salts containing sugar substituents. Among them four group of compounds arises: salts linked to C6 atom in sugar, directly connected to anomeric carbon atom, linked trough hydrocarbon spacer and derivatives of polisacharides. Kirk at al. described the synthesis of biologically active QACs [15]. In the Menshutkin reaction between an iodo-derivative and trimethylamine (Scheme 4), these authors obtained compounds with bactericidal and fungicidal properties. The authors obtained a series of analogous compounds using carboxylic acids (with carbon chains of various lengths) ester linked to the C-6-OH group of a sugar derivative. Blizzard synthesized QAC derivatives of vancomycin [28]. It was noticed that the increased hydrophilicity of vancomycin following the addition to it of a suitable fragment enhanced its antibacterial properties [30, 31], one of the more active being a derivative containing an aminium group at position G-6 (Scheme 10). Examples of reactions, in which the terminal carbon atoms in methyl glucopyranosides and polysaccharides are functionalized, are the syntheses carried out by Engel et al. [33, 34], one of which is shown in Figure 5. These authors aimed to find compounds with antibacterial properties. In the first instance, the hydroxyl groups at atoms C-6 of the sugar units in cellulose were O-tosylated. Then, the terminal carbons were functionalized with tertiary amines, yielding QACs. The most effective bactericide among these compounds was the one with a 16-carbon chain, the structure of which is shown Figure 6.
    Źródło:
    Wiadomości Chemiczne; 2016, 70, 7-8; 497-518
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ warunków parzenia na zawartość antyoksydantow w naparach różnych rodzajów herbat
    Influence of brewing conditions on antioxidant content in different kinds of tea infusions
    Autorzy:
    Kurleto, K.
    Kurowski, G.
    Laskowska, B.
    Malinowska, M.
    Sikora, E.
    Vogt, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/172172.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    herbata
    antyoksydanty
    całkowita aktywność antyoksydacyjna
    tea
    antioxidants
    total antioxidant capacity
    Opis:
    Tea has been consumed all over the World for over two thousand years and now it is the most popular caffeine-containing beverage. Its worldwide consumption is second only to water [1–3]. The tea is not only important because of its popularity but also due to its beneficial influence on human health [4]. The biological benefits of tea are due to their flavanol content [5–13]. Tea flavanols are a group of natural polyphenols (Fig. 2). Therapeutic effects of tea have been extensively examined in many in vitro and in vivo tests. It was confirmed that tea leaves ingredients have antibacterial, antifungial, antiviral properties, they also prevent cell mutations and they inhibit progress of heart diseases. Moreover, tea can stimulate neural system and regulate its functions [14–20]. All this activities are mostly due to antioxidant ability of tea polyphenols (Fig. 4). Tea production process can be run in different ways and this affects of the tea taste, aroma, colour and antioxidants content. According to fermentation degree, different tea kinds can be obtained (Fig. 1). During the manufacturing process of black and oolong teas, tea leaves are crushed to allow polyphenol oxidase to catalyze the oxidation and polymerization of catechins to polymers called theaflavins and thearubigins (Fig. 3) [21–23]. Green or white teas are obtained through shorter fermentation, so the catechin concentration remains higher. Tea is prepared by infusing tea leaves in hot water. Brewing process conditions like temperature, brewing time, pH, besides other factors has a significant influence on polyphenols content [24-32]. Many studies have determined total flavonoids content and antioxidant activity according to different tea type and brewing conditions, tea plantation type or fermentation process. The amount of total polyphenol was determined using the F-C method, catechins, caffeine and polyphenolic acids were analysed using High Performance Liquid Chromatography with reversed phase. Obtained results let compare how different production and brewing processes affect the tea quality [33–56].
    Źródło:
    Wiadomości Chemiczne; 2013, 67, 11-12; 1129-1147
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-3 z 3

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies