120 research outputs found

    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

    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

    Microarray and Proteomic Analyses of Myeloproliferative Neoplasms with a Highlight on the mTOR Signaling Pathway

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    The gene and protein expression profiles in myeloproliferative neoplasms (MPNs) may reveal gene and protein markers of a potential clinical relevance in diagnosis, treatment and prediction of response to therapy. Using cDNA microarray analysis of 25,100 unique genes, we studied the gene expression profile of CD34(+) cells and granulocytes obtained from peripheral blood of subjects with essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF). The microarray analyses of the CD34(+) cells and granulocytes were performed from 20 de novo MPN subjects: JAK2 positive ET, PV, PMF subjects, and JAK2 negative ET/PMF subjects. The granulocytes for proteomic studies were pooled in 4 groups: PV with JAK2 mutant allele burden above 80%, ET with JAK2 mutation, PMF with JAK2 mutation and ET/PMF with no JAK2 mutation. The number of differentially regulated genes was about two fold larger in CD34(+) cells compared to granulocytes. Thirty-six genes (including RUNX1, TNFRSF19) were persistently highly expressed, while 42 genes (including FOXD4, PDE4A) were underexpressed both in CD34(+) cells and granulocytes. Using proteomic studies, significant up-regulation was observed for MAPK and PI3K/AKT signaling regulators that control myeloid cell apoptosis and proliferation: RAC2, MNDA, S100A8/9, CORO1A, and GNAI2. When the status of the mTOR signaling pathway related genes was analyzed, PI3K/AKT regulators were preferentially up-regulated in CD34(+) cells of MPNs, with down-regulated major components of the protein complex EIF4F. Molecular profiling of CD34(+) cells and granulocytes of MPN determined gene expression patterns beyond their recognized function in disease pathogenesis that included dominant up-regulation of PI3K/AKT signaling

    The Cytosolic Protein G0S2 Maintains Quiescence in Hematopoietic Stem Cells

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    Bone marrow hematopoietic stem cells (HSCs) balance proliferation and differentiation by integrating complex transcriptional and post-translational mechanisms regulated by cell intrinsic and extrinsic factors. We found that transcripts of G0/G1 switch gene 2 (G0S2) are enriched in lineage− Sca-1+ c-kit+ (LSK) CD150+ CD48− CD41− cells, a population highly enriched for quiescent HSCs, whereas G0S2 expression is suppressed in dividing LSK CD150+ CD48− cells. Gain-of-function analyses using retroviral expression vectors in bone marrow cells showed that G0S2 localizes to the mitochondria, endoplasmic reticulum, and early endosomes in hematopoietic cells. Co-transplantation of bone marrow cells transduced with the control or G0S2 retrovirus led to increased chimerism of G0S2-overexpressing cells in femurs, although their contribution to the blood was reduced. This finding was correlated with increased quiescence in G0S2-overexpressing HSCs (LSK CD150+ CD48−) and progenitor cells (LS−K). Conversely, silencing of endogenous G0S2 expression in bone marrow cells increased blood chimerism upon transplantation and promoted HSC cell division, supporting an inhibitory role for G0S2 in HSC proliferation. A proteomic study revealed that the hydrophobic domain of G0S2 interacts with a domain of nucleolin that is rich in arginine-glycine-glycine repeats, which results in the retention of nucleolin in the cytosol. We showed that this cytosolic retention of nucleolin occurs in resting, but not proliferating, wild-type LSK CD150+ CD48− cells. Collectively, we propose a novel model of HSC quiescence in which elevated G0S2 expression can sequester nucleolin in the cytosol, precluding its pro-proliferation functions in the nucleolus
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