142 research outputs found

    Chromatic numbers for facet colouring of some generalized associahedra

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    The chromatic number of a proper colouring of the facets of certain classes of generalized associahedra is studied. The exact values are obtained for the permutohedron and the associahedron, while lower and upper bounds are established for the nn-dimensional cyclohedron, astrohedron and simple permutoassociahedron

    Logistics processes in a tourism destination

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    The purpose of this paper is to underline the importance of understanding tourism destinations as organisational systems, examine logistics as a system or subsystem of the tourism destination system, and identify and define the logistics processes that are involved in creating the product of a tourism destination. The paper is based on the assumption that logistics processes play an important role in shaping the offering of a tourism destination. Understanding tourism destinations as organisational systems can help in optimising logistics flows, and this is becoming a vital precondition to creating a well-designed offering for a tourism destination

    Karakterizacija endopeptidaza srednjeg creva larvi Morimus funereus (Coleoptera: Cerambycidae)

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    Application of specific chromogenic substrates, use of class-specific inhibitors, and zymogram analysis enabled us to identify several peptidase classes in extracts of the midgut of Morimus funereus larvae. Zymogram analysis with gelatin as a peptidase substrate and phenylmethylsulfonyl fluoride as an inhibitor showed that serine peptidases were the most abundant endopeptidases in the midgut of M. funereus larvae. By zymogram analysis with gelatin as a peptidase substrate and 1,10-phenanthroline as an inhibitor, metallopeptidases were also detected. Analyses of serine peptidases with specific chromogenic substrates revealed dominance of elastase-like peptidases in extracts of the midgut of M. funereus larvae, with less pronounced chymotrypsin- and trypsin-like activities.Primenom specifičnih hromogenih supstrata, klasno-specifičnih inhibitora i zimogramske analize identifikovano je nekoliko klasa peptidaza u sirovom ekstraktu srednjeg creva larvi koleoptere Morimus funereus. Zimogramskom analizom sa želatinom kao supstratom i fenilmetilsulfonil-fluoridom kao inhibitorom utvrđeno je da su serin-peptidaze najzastupljenije peptidaze u ekstraktu srednjeg creva larvi M. funereus. Zimogramskom analizom sa želatinom kao supstratom i 1,10-fenantrolinom kaoinhibitorom takođe su detektovane metalopeptidaze. Analizom serin-peptidaza, upotrebom specifičnih hromogenih supstrata, dokazano je da su dominantni elastazi-slični enzimi u sirovom ekstraktu srednjeg creva larvi M. funereus, dok su himotripsinima- i tripsinima-slični enzimi manje zastupljeni

    Uporedna analiza izoformi α-amilaze iz srednjeg creva larvi Cerambyx cerdo L. (Coleoptera: Cerambycidae) iz prirode i gajenih na veštačkoj podlozi

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    alpha-Amylase isoforms of Cerambyx cerdo larvae from the wild (ML and SL) and reared in the laboratory (ADL) were compared. Three amylase isoforms were presented in the SL and ML extracts while two isoforms were presented in the ADL according to zymogram after isoelectric focusing (IEF). All C. cerdo amylase isoforms were acidic proteins (pI lt 3.5). Seven amylase isoforms (ACC 1-7) from the midgut of C. cerdo larvae were found in the ML midgut extract, six in the SL extract, and four in the ADL extract according to native PAGE zymogram. The ADL amylase had the highest activity. All crude midgut extracts of C. cerdo larvae were fractionated on a Superose 12 HR column. The molecular mass of the ACC was estimated to be 34 kDa.Upoređene su izoforme α-amilaze larvi Cerambyx cerdo sakupljenih iz prirode (ML i SL) i gajenih na veštačkoj podlozi u laboratoriji (ADL). Zimogramskom detekcijom posle IEF-a po tri izoforme su detektovane u ML i SL ekstraktima, a u ADL dve izoforme. Sve amilazne izoforme iz C. cerdo su bile kisele (pI lt 3.5). Zimogramskom detekcijom posle nativne elektroforeze sedam izoformi je detektovano u ML ekstraktu, šest u SL ekstraktu i četiri u ADL ekstraktu. Najveća amilazna aktivnost je detektovana u ADL ekstraktu. Svi ekstrakti srednjih creva larvi C. cerdo su frakcionisani na koloni Superose 12 HR. Molekulska masa ACC-a je bila 34 kDa

    Sinteza i farmakološko ispitivanje (±)-2,3-seco-analoga fentanila

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    An efficient, five-step synthetic approach to various acyclic 1,3-diamines has been developed and applied to the preparation of a novel class of open-chained fentanyl analogues. The acyclic derivatives 5.1-5.5 (all new compounds) were synthesized with the aim of estimating the significance of the piperidine ring for the opioid analgesic activity of anilido-piperidines. The starting beta-keto-amide 1.1, prepared by the aminolysis of methyl acetoacetate with methyl phenethylamine, (93% yield), was successively reacted with NaH and BuLi, to form the highly reactive alpha,gamma-dienolate anion 1.1a. Regio and chemoselective gamma-alkylation of the dienolate with various primary and secondary alkyl halides furnished the beta-keto-amides 1.2-1.5 (76-91%). Reductive amination of the keto-amides 1.1-1.5 with aniline and Zn powder in acetic acid, via the enamine intermediates 2.1-2.5. afforded the beta-anilino amides 3.1-3.5 (74-85%). After reductive deoxygenation of the tertiary amide group, using in situ generated diborane, the corresponding 1,3-diamines 4.1-4.5 were obtained (87-97%). The synthesis of (+/-)-2,3-seco-fentanyls 5.1-5.5 was completed by N-acylation of the diamines 4.1-4.5 with propionyl chloride, followed by precipitation of the monooxalate salts (86-95%). The parent compound, 2,3-seco-fentanyl 5.1, was found to be a 40 times less potent narcotic analgesic than fentanyl but still 5-6 times more active than morphine in rats. while i-Pr derivative 5.3 was inactive. Apart from the pharmacological significance. the general procedure described herein may afford various functionalized, 1,3-diamines as potential complexing agents and building blocks for the synthesis of aza-crown ethers.Razvijen je efikasan postupak za dobijanje različitih acikličnih 1,3-diamina u pet faza, i primenjen u sintezi nove klase analoga fentanila otvorenog niza. Derivati 5.1–5.5 (svi su nova jedinjenja) sintetisani su sa ciljem da se proceni uticaj piperidinskog prstena na opioidnoanalgetičku aktivnost anilido-piperidina. Polazni β-keto-amid 1.1, dobijen aminolizom metilacetoacetata metilfenetilaminom (prinos 93 %), bio je sukcesivno tretiran sa NaH i BuLi, pri čemu je postao veoma reaktivni α,γ-dienolatni anjon 1.1a. Regio- i hemoselektivnim γ-alkilovanjem ovog dienolata različitim primarnim i sekundarnim alkil-halogenidima, dobijeni su β-keto-amidi 1.2–1.5 (prinos 76–91 %). Reduktivnim aminovanjem keto-amida 1.1–1.5 pomoću Zn praha i sirćetne kiseline, preko enaminskih intermedijera 2.1–2.5, postali su -anilino-amidi 3.1–3.5 (prinos 74–85 %). Posle reduktivne deoksigenacije tercijene amidne funkcije, koristeći in situ generisani diboran, odgovarajući 1,3-diamini 4.1–4.5 izolovani su u prinosima 87–97 %. Sinteza (±)-2,3-seco-fentanila 5.1–5.5 završena je N-acilovanjem diamina 4.1–4.5 propionil-hloridom, a zatim taloženjem u obliku monooksalatnih soli (prinos 86–95 %). Nađeno je da je osnovno jedinjenje, 2,3-seco fentanil 5.1, 40 puta slabiji narkotički analgetik od fentanila, ali još uvek 5–6 puta aktivniji od morfina u pacova, dok je i-Pr derivat 5.3 bio neaktivan. Osim farmakološkog značaja, opštim postupkom prikazanim u ovom radu, mogu se sintetisati različiti 1,3-diamini, uključujući i one sa funkcionalnim grupama. Ova jedinjenja mogu biti potencijalno značajna kao kompleksirajući agensi i kao intermedijeri u sintezi aza-kraun-etara

    Effect of AGM and Fetal Liver-Derived Stromal Cell Lines on Globin Expression in Adult Baboon (P. anubis) Bone Marrow-Derived Erythroid Progenitors

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    This study was performed to investigate the hypothesis that the erythroid micro-environment plays a role in regulation of globin gene expression during adult erythroid differentiation. Adult baboon bone marrow and human cord blood CD34+ progenitors were grown in methylcellulose, liquid media, and in co-culture with stromal cell lines derived from different developmental stages in identical media supporting erythroid differentiation to examine the effect of the micro-environment on globin gene expression. Adult progenitors express high levels of γ-globin in liquid and methylcellulose media but low, physiological levels in stromal cell co-cultures. In contrast, γ-globin expression remained high in cord blood progenitors in stromal cell line co-cultures. Differences in γ-globin gene expression between adult progenitors in stromal cell line co-cultures and liquid media required cell-cell contact and were associated with differences in rate of differentiation and γ-globin promoter DNA methylation. We conclude that γ-globin expression in adult-derived erythroid cells can be influenced by the micro-environment, suggesting new potential targets for HbF induction
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