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  • 1201.
    Zhu, Mingzhao
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lin, Shuangzheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Organocatalytic diastereoselective dibromination of alkenes2010Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 20, s. 2708-2712Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A highly diastereoselective pyrrolidine-promoted dibromination of alkenes by combination of NBS and succinimide is presented. The pyrrolidine-mediated dibromination of alkenes is higly anti-selective and gives the corresponding products in moderate to high yields and up to >25:1 dr.

  • 1202.
    Zmudzka, Katarzyna
    et al.
    Polish Acad Sci, Ctr Mol & Macromol Studies.
    Johansson, Tommy
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wojcik, Marzena
    Polish Acad Sci, Ctr Mol & Macromol Studies.
    Janicka, Magdalena
    Polish Acad Sci, Ctr Mol & Macromol Studies.
    Nowak, Marian
    Polish Acad Sci, Ctr Mol & Macromol Studies.
    Stawinski, Jacek
    Nawrot, Barbara
    Polish Acad Sci, Ctr Mol & Macromol Studies.
    Novel DNA Analogues with 2-, 3- and 4-Pyridylphosphonate Internucleotide Bonds: Synthesis and Hybridisation Properties2003Ingår i: New Journal of Chemistry, ISSN 1144-0546, Vol. 27, nr 12, s. 1698-1705Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oligothymidylates modified with stereodefined 2-pyridyl-, 3-pyridyl- and 4-pyridylphosphonate moieties at one or two juxtaposed internucleotide positions were prepared, and their avidity towards complementary single stranded DNA and RNA, as well as toward double stranded DNA were evaluated by UV melting temperature and CD studies. It was found that the sense of chirality at the phosphorus centre and the position of the nitrogen atom in the pyridyl ring of a pyridylphosphonate moiety are important factors governing stability of double- and triple-stranded complexes formed by these oligonucleotides. DNA/DNA and DNA/RNA duplexes containing oligothymidylate strands with R-P-pyridylphosphonate units differed only slightly from unmodified reference complexes. In contrast to this, the S-P-pyridylphosphonate derivatives exhibited lower binding affinity than both their R-P-counterparts and the unmodified reference oligonucleotide T-20. Triplexes of oligo(thymidyl pyridylphosphonate)s with hairpin oligomer d(A(21)C(4)T(21)) were found mostly to be thermodynamically slightly more stable in pH 7.4 and less stable in pH 5.0 than non-modified complexes. As expected, oligonucleotides with pyridylphosphonate internucleotide bonds were recognised by 3'- and 5'-exonucleases but the chimeric oligonucleotide chains were not cleaved at the modi. cation sites.

  • 1203. Zou, Dapeng
    et al.
    Andersson, Samir
    Zhang, Rong
    Sun, Shiguo
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    A host-induced intramolecular charge-transfer complex and light-driven radical cation formation of a molecular triad with cucurbit[8]uril2008Ingår i: The Journal of Organic Chemistry, ISSN 0022-3263, Vol. 73, nr 10, s. 3775-3783Artikel i tidskrift (Refereegranskat)
  • 1204. Zou, Dapeng
    et al.
    Andersson, Samir
    Zhang, Rong
    Sun, Shiguo
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Selective binding of cucurbit[7]uril and beta-cyclodextrin with a redox-active molecular triad Ru(bpy)3-MV2+-naphthol2007Ingår i: Chemical Communications, ISSN 1359-7345, nr 45, s. 4734-4736Artikel i tidskrift (Refereegranskat)
  • 1205.
    Zou, Xiaodong
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yao, Qingxia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bermejo Gómez, Antonio
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Su, Jie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Pascanu, Vlad
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Yifeng, Yun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zheng, Haoquan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Chen, Hong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Liu, Leifeng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Abdelhamid, Hani N.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A series of highly stable isoreticular lanthanide metal-organic frameworks with tunable luminescence properties solved by rotation electron diffraction and X-ray diffraction2016Ingår i: Acta Crystallographica Section A: Foundations of Crystallography, ISSN 0108-7673, E-ISSN 1600-5724, Vol. A72, s. 136-136Artikel i tidskrift (Refereegranskat)
  • 1206. Zovko, Ana
    et al.
    Novak, Metka
    Hååg, Petra
    Kovalerchick, Dimitry
    Holmlund, Teresa
    Färnegårdh, Katarina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Ilan, Micha
    Carmeli, Shmuel
    Lewensohn, Rolf
    Viktorsson, Kristina
    Compounds from the marine sponge Cribrochalina vasculum offer a way to target IGF-1R mediated signaling in tumor cells2016Ingår i: OncoTarget, ISSN 1949-2553, E-ISSN 1949-2553, Vol. 7, nr 31, s. 50258-50276Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work two acetylene alcohols, compound 1 and compound 2, which were isolated and identified from the sponge Cribrochalina vasculum, and which showed antitumor effects were further studied with respect to targets and action mechanisms. Gene expression analyses suggested insulin like growth factor receptor (IGF-1R) signaling to be instrumental in controlling anti-tumor efficacy of these compounds in non-small cell lung cancer (NSCLC). Indeed compounds 1 and 2 inhibited phosphorylation of IGF-1R beta as well as reduced its target signaling molecules IRS-1 and PDK1 allowing inhibition of pro-survival signaling. In silico docking indicated that compound 1 binds to the kinase domain of IGF-1R at the same binding site as the well known tyrosine kinase inhibitor AG1024. Indeed, cellular thermal shift assay (CETSA) confirmed that C. vasculum compound 1 binds to IGF-1R but not to the membrane localized tyrosine kinase receptor EGFR. Importantly, we demonstrate that compound 1 causes IGF-1R beta but not Insulin Receptor degradation specifically in tumor cells with no effects seen in normal diploid fibroblasts. Thus, these compounds hold potential as novel therapeutic agents targeting IGF-1R signaling for anti-tumor treatment.

  • 1207. Zovko, Ana
    et al.
    Viktorsson, Kristina
    Haag, Petra
    Kovalerchick, Dimitry
    Farnegardh, Katarina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Alimonti, Andrea
    Ilan, Micha
    Carmeli, Shmuel
    Lewensohn, Rolf
    Marine Sponge Cribrochalina vasculum Compounds Activate Intrinsic Apoptotic Signaling and Inhibit Growth Factor Signaling Cascades in Non-Small Cell Lung Carcinoma2014Ingår i: Molecular Cancer Therapeutics, ISSN 1535-7163, E-ISSN 1538-8514, Vol. 13, nr 12, s. 2941-2954Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Marine-derived compounds have been explored and considered as possible antitumor agents. In this study, we analyzed extracts of the sponge Cribrochalina vasculum for their ability to inhibit tumor cell proliferation. Screening identified two acetylenic compounds of similar structure that showed strong tumor-specific toxicity in non-small cell lung carcinoma (NSCLC) cells and small-cell lung carcinoma cells, and less prominent toxicity in ovarian carcinoma, while having no effect on normal cells. These acetylenic compounds were found to cause a time-dependent increase in activation of apoptotic signaling involving cleavage of caspase-9, caspase-3, and PARP, as well as apoptotic cell morphology in NSCLC cells, but not in normal fibroblasts. Further analysis demonstrated that these compounds caused conformational change in Bak and Bax, and resulted in loss of mitochondrial potential and cytochrome c release in NSCLC cells. Moreover, a decreased phosphorylation of the growth factor signaling kinases Akt, mTOR, and ERK was evident and an increased phosphorylation of JNK was observed. Thus, these acetylenic compounds hold potential as novel therapeutic agents that should be further explored for NSCLC and other tumor malignancies.

  • 1208.
    Åberg, Jenny B.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Investigation of a possible solvent cage effect in the reduction of 4-aminocyclohexanone by a hydroxycyclopentadienyl ruthenium hydride2008Ingår i: Chemistry: a European Journal, ISSN 0947-6539, Vol. 14, nr 30, s. 9169-9174Artikel i tidskrift (Refereegranskat)
  • 1209.
    Åberg, Jenny B.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nyhlén, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Privalov, Timofei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    CO Assistance in ligand exchange of a ruthenium racemization catalyst: identification of an acyl intermediate2009Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, nr 27, s. 9500-9501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An acyl intermediate in the activation of eta(5)-(Ph(5)Cp)Ru(CO)(2)Cl by t-BuOK was identified by means of in situ FT-IR measurements and NMR spectroscopy. This strongly supports the conclusion that the ligand exchange takes place via CO assistance, i.e., that the activation occurs via nucleophilic attack by tert-butoxide on one of the CO ligands. The tert-butoxycarbonyl intermediate shows stretching vibrations at 1933 and 1596 cm(-1), corresponding to the CO and COOt-Bu groups, respectively. In the (13)C NMR spectrum, the CO group appears at 209.5 ppm and the COOt-Bu group at 208.7 ppm. The NMR assignments were confirmed by density functional theory calculations. The subsequent alcohol-alkoxide exchange is also thought to take place via CO assistance. However, no intermediate in that step could be detected.

  • 1210.
    Åberg, Jenny B.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Warner, Madeleine C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Unexpected formation of a cyclopentadienylruthenium alkoxycarbonyl complex with a coordinated C=C bond2009Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, nr 38, s. 13622-13624Artikel i tidskrift (Refereegranskat)
  • 1211.
    Åberg, Jenny
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mechanistic Investigation on the Hydrogenation of Imines by [p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3). Experimental support for an  Ionic Pathway2006Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, nr 26, s. 2771-2773Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The need for acidic activation in the stoichiometric hydrogenation of benzyl-[1-phenyl-ethylidene]-amine ( 6a) or [1-(4-methoxy-phenyl)-ethylidene]-methyl-amine ( 6b) by Noyori's catalyst [p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3)( 2) is inconsistent with the proposed concerted mechanism and supports an ionic mechanism.

  • 1212.
    Åkermark, Björn
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sjögren, Magnus P.T.
    Iron-catalyzed nucleophilic substitution of allylic acetate2007Ingår i: Advanced Synthesis & Catalysis, ISSN 1615-4150, Vol. 349, nr 17-18, s. 2641-2646Artikel i tidskrift (Refereegranskat)
  • 1213.
    Éll, Alida H
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Csjernyik, Gábor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Slagt, Vincent F
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Berner, Simon
    Puglia, Carla
    Greger, Ledung
    Oscarsson, Sven
    Synthesis os S-Thioacetate Functionalized Cobalt(II) Porphyrins and Heterogenization on gold Surface2006Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 5, s. 1193-1199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cobalt tetraarylporphyrins 1-Co and 2-Co with thioacetate-functionalized carbon chains on the aryl groups were synthesized. The cobalt porphyrin 2-Co was immobilized on a gold surface after deprotection of the S-acetyl group. The immobilized porphyrin was studied by X-ray Photoelectron Spectroscopy (XPS) and the results suggest that a complete monolayer of porphyrins is formed.

  • 1214. Éll, Alida H
    et al.
    Samec, Joseph S M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Brasse, Claudia
    Bäckvall, Jan-E
    Dehydrogenation of aromatic amines to imines via ruthenium-catalyzed hydrogen transfer2002Ingår i: Chemical Communications, ISSN 1359-7345, nr 10, s. 1144 - 1145Artikel i tidskrift (Refereegranskat)
  • 1215. Öksnes Dalheim, Marianne
    et al.
    Björk Arnfinnsdottir, Nina
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Christensen, Björn E.
    The size and shape of three water-soluble, non-ionic polysaccharides produced by lactic acid bacteria: A comparative study2016Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 142, s. 91-97Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three water-soluble, non-ionic extracellular polysaccharides (EPS) obtained from lactic acid bacteria (S. thermophilus THS, L. helveticus K16 and S. thermophilus ST1) were subjected to a comparative study by means of multidetector size-exclusion chromatography, providing distributions and averages of molar masses, radii of gyration and intrinsic viscosities. All polysaccharides displayed random coil character. Further analysis of the data reveals differences in chain stiffness and extension that could be well correlated to structural features. The calculated persistence lengths ranged from 5 to 10 nm and fall within the range typical for many single-stranded bacterial or plant polysaccharides. The ST1 polysaccharide had the highest molar mass but the lowest persistence length, which is attributed to the presence of the flexible (1→6)-linkage in the main chain.

  • 1216. Číhalová, Sylva
    et al.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Veselý, Jan
    Asymmetric Aza-Morita–Baylis–Hillman-type reactions: The highly enantioselective reaction between unmodified α,β-unsaturated aldehydes and N-acylimines by organo-co-catal2011Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 353, nr 7, s. 1096-1108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The highly enantioselective organo-co-catalytic aza-Morita–Baylis–Hillman (MBH)-type reaction between N-carbamate-protected imines and α,β-unsaturated aldehydes has been developed. The organic co-catalytic system of proline and 1,4-diazabicyclo[2.2.2]octane (DABCO) enables the asymmetric synthesis of the corresponding N-Boc- and N-Cbz-protected β-amino-α-alkylidene-aldehydes in good to high yields and up to 99% ee. In the case of aza-MBH-type addition of enals to phenylprop-2-ene-1-imines, the co-catalytic reaction exhibits excellent 1,2-selectivity. The organo-co-catalytic aza-MBH-type reaction can also be performed by the direct highly enantioselective addition of α,β-unsaturated aldehydes to bench-stableN-carbamate-protected α-amidosulfones to give the corresponding β-amino-α-alkylidene-aldehydes with up to 99% ee.The organo-co-catalytic aza-MBH-type reaction is also an expeditious entry to nearly enantiomerically pure β-amino-α-alkylidene-amino acids and β-amino-α-alkylidene-lactams (99% ee). The mechanism and stereochemistry of the chiral amine and DABCO co-catalyzed aza-MBH-type reaction arealso discussed.

  • 1217.
    Šoltésová, Mária
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Charles University in Prague.
    Kowalewski, Jozef
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dynamics of exocyclic groups in the Escherichia coli O91 O-antigen polysaccharide in solution studied by carbon-13 NMR relaxation2013Ingår i: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 57, nr 1, s. 37-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon-13 relaxation data are reported for exocyclic groups of hexopyranosyl sugar residues in the repeating unit within the Escherichia coli O91 O-antigen polysaccharide in a dilute D2O solution. The measurements of T 1, T 2 and heteronuclear nuclear Overhauser enhancements were carried out at 310 K at two magnetic fields (16.4 T, 21.1 T). The data were analyzed using the standard and extended Lipari–Szabo models, as well as a conformational jump model. The extended version of the Lipari–Szabo and the two-site jump models were most successful for the hydroxymethyl groups of Gal and GlcNAc sugar residues. Different dynamics was found for the hydroxymethyl groups associated with different configurations (d-gluco, d-galacto) of the sugar residues, the latter being faster than the former.

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