2,220 research outputs found
Provenance does matter: links between winter trophic segregation and the migratory origins of European robins
Amongst migratory species, it is common to find individuals from different populations or geographical origins sharing staging or wintering areas. Given their differing life histories, ecological theory would predict that the different groups of individuals should exhibit some level of niche segregation. This has rarely been investigated because of the difficulty in assigning migrating individuals to breeding areas. Here, we start by documenting a broad geographical gradient of hydrogen isotopes (δ2H) in robin Erithacus rubecula feathers across Europe. We then use δ2H, as well as wing-tip shape, as surrogates for broad migratory origin of birds wintering in Iberia, to investigate the ecological segregation of populations. Wintering robins of different sexes, ages and body sizes are known to segregate between habitats in Iberia. This has been attributed to the despotic exclusion of inferior competitors from the best patches by dominant individuals. We find no segregation between habitats in relation to δ2H in feathers, or to wing-tip shape, which suggests that no major asymmetries in competitive ability exist between migrant robins of different origins. Trophic level (inferred from nitrogen isotopes in blood) correlated both with δ2H in feathers and with wing-tip shape, showing that individuals from different geographic origins display a degree of ecological segregation in shared winter quarters. Isotopic mixing models indicate that wintering birds originating from more northerly populations consume more invertebrates. Our multi-scale study suggests that trophic-niche segregation may result from specializations (arising in the population-specific breeding areas) that are transported by the migrants into the shared wintering grounds
3-Aminopyrroles and their application in the synthesis ofpyrrolo[3,2-d]pyrimidine (9-deazapurine) derivatives
3-Aminopyrrole derivatives have been synthesized from 3-anilino-2-cyanoacrylonitrile using
Thorpe-Ziegler cyclization. These substituted pyrroles are readily converted into 5H-pyrrolo[3,2-
d]pyrimidine (9-deazapurines).FEDERFundação para a Ciência e Tecnologia (FCT
Synthesis of some novel pyrazolo[3,4-d]pyrimidine derivatives
Reaction of ethyl imidates derived from N-aryl-5-amino-4-cyanopyrazoles with amines or
arylhydrazines gave only 4-substituted pyrazolo[3,4-d]pyrimidines, resulting from cyclization
followed by Dimroth rearrangement. From the reaction with arylhydrazines, a mixture of the
hydrazines and their oxidized forms, the azo products, was obtained. This was proven by an
independent synthesis starting from the corresponding 4-chloropyrazolo[3,4-d]pyrimidines as
starting material. The structures of the compounds obtained were confirmed by mass
spectrometry, 1H and 13C NMR.Fundação para a Ciência e Tecnologia (FCT) - POCTI-SFA-3-686, SFRH/BPD/31490/2006FEDE
Heterocyclic synthesis with nitriles: synthesis of pyridazine and pyridopyridazine derivatives
The reaction of MND with aryldiazonium chlorides followed by cyclization afforded
the pyridazinimine derivatives. Reaction of the latter with another mole of malononitrile
produce only pyrido[3,2-c]pyridazine derivatives. Reaction of 4-aminopyridazinone-3-
carboxylic acid esters with malononitrile gave only pyridazine-3-carboxylic acid.Fundação para a Ciência e a Tecnologia (FCT) - POCTI-SFA-3-686, SFRH/BPD/31490/2006Fundo Europeu de Desenvolvimento Regional (FEDER
Studies on the reaction of morita-baylis-hillman with indole and carbazole derivatives
Fundação para a Ciência e a Tecnologia (FCT)and FEDE
Synthesis and characterization of psoralen analogues based on carbazoles
Novel psoralen analogues based on carbazoles were synthesized and characterized.Fundação para a Ciência e Tecnologia (FCT) and FEDER, for National NMR Networ
Synthesis of 5H-pyrido[4,3-b]indole by a modification of Pomeranz-Fritsch isoquinoline synthesis.
5H-Pyrido[4,3-b]indole was obtained from 3-formylindole in 16% overall
yield by Jackson and Shannon modification of the Pomeranz-Fristch isoquinoline
synthesis. The final cyclisation occurred but the removal of the tosyl group and
oxidation of the dihydrocompound was not efficient. Changes in the concentration of
the acid catalyst gave 29% as the best yield for the last step. An NMR study of the
cyclisation is described.Fundação para a Ciência e Tecnologia (FCT)
and FEDE
Bozepinib: A Promising Selective Derivative Targeting Breast Cancer Stem Cells
Bozepinib is a potent antitumour compound that shows an IC50 of 0.166 μM against MDA-MB-231 human breast cancer cell line. It is also a very selective drug that presents a therapeutic index (TI) of 11.0 against MDA-MB-231 in relation to the normal MCF-10A. It is important to identify new cancer stem-like cells (CSCs) anticancer drugs to struggle against the resistance and the high risk of relapse in patients. In the present chapter, we show how bozepinib demonstrated selectivity on cancer cells and showed an inhibitory effect over kinases involved in carcinogenesis, proliferation and angiogenesis. Bozepinib inhibits HER-2 signaling pathway and JNK and ERK kinases. In addition, it has an inhibitory effect on AKT and VEGF together with anti-angiogenic and anti-migratory activities. Interestingly, bozepinib suppresses the formation of both mammo- and colonospheres and eliminated ALDH+ CSC subpopulations at a low micromolar range similar to salinomycin. It also induces the downregulation of SOX2, c-MYC and β-CATENIN and upregulation of the GLI-3 Hedgehog signaling repressor. Finally, bozepinib shows in vivo antitumor and anti-metastatic efficacy in xenotransplanted nude mice without presenting subacute toxicity. However, further studies in cancer patients are needed to confirm the therapeutic potential of bozepinib
Synthesis and characterization of psoralen analogues based on dibenzofuran
Fundação para a Ciência e Tecnologia (FCT) and FEDER, for National NMR Networ
Alternative products to carbazoles in the oxidation of diphenylamines with palladium (II) acetate
Although simple diphenylamines are conveniently oxidised with Palladium (II) acetate to give carbazoles, for more complex examples, carbazoles are minor products amongst many.CRUP (Portugal).
British Council - Treaty of Windsor Programme.
Junta Nacional de Investigação Científica e Tecnológica
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