169 research outputs found

    TÔrva TantsumÀe muinaslinnus

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    http://tartu.ester.ee/record=b2653959~S1*es

    Methyl­ergometrine maleate from synchrotron powder diffraction data

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    The title compound {systematic name: 9,10-didehydro-N-[1-(hydroxy­meth­yl)prop­yl]-d-lysergamide maleate}, C20H26N3O2 +·C4H3O4 −, contains a large rigid ergolene group. This group consists of an indole plane connected to a six-membered carbon ring adopting an envelope conformation and N-methyl­tetra­hydro­pyridine where the methyl group is in an equatorial position. In the crystal, inter­molecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds form an extensive three-dimensional hydrogen-bonding network, which holds the cations and anions together

    1-(2â€Č,4â€Č-Difluoro­biphenyl-4-yl)ethanone

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    In the crystal structure of the title compound, C14H10F2O, the dihedral angles between the benzene rings in the two crystallographically independent mol­ecules are 46.9 (2) and 47.6 (2)°. The mol­ecules are linked into dimers by C—H⋯F inter­actions and these dimers are further stacked into columns along the b axis by π–π inter­actions between the benzene rings [centroid–centroid distance = 3.8221 Å; the dihedral angle between the planes of these rings is 4.87 (2)°]. In addition, C—Fâ‹ŻÏ€ interactions also contribute to the crystal packing (C⋯centroid distance = 3.5919 Å)

    Norleucine, a natural occurrence in a novel ergot alkaloid Îł-ergokryptinine

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    A novel natural peptide ergot alkaloid γ-ergokryptinine containing norleucine has been isolated from ergot sclerotia of the field-growing parasitic fungus Claviceps purpurea CCM 8059. Its structure was deduced from the NMR and mass spectral data. The final structural proof was provided by the crystal structure determination, which is the first X-ray structure of a natural Nle-containing secondary metabolite. The conformations of three ergopeptinines: γ-ergokryptinine, ergoladinine, and α-ergokryptinine were compared. © Springer-Verlag 2005

    Capecitabine from X-ray powder synchrotron data

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    In the title compound [systematic name 5-de­oxy-5-fluoro-N-(pent­yloxycarbon­yl)cytidine], C15H22FN3O6, the pentyl chain is disordered over two positions with refined occupancies of 0.53 (5) and 0.47 (5). The furan ring assumes an envelope conformation. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains propagating along the b axis. The crystal packing exhibits electrostatic inter­actions between the 5-fluoro­pyrimidin-2(1H)-one fragments of neighbouring mol­ecules as indicated by short O⋯C [2.875 (3) and 2.961 (3) Å] and F⋯C [2.886 (3) Å] contacts

    Mitochondria and Energetic Depression in Cell Pathophysiology

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    Mitochondrial dysfunction is a hallmark of almost all diseases. Acquired or inherited mutations of the mitochondrial genome DNA may give rise to mitochondrial diseases. Another class of disorders, in which mitochondrial impairments are initiated by extramitochondrial factors, includes neurodegenerative diseases and syndromes resulting from typical pathological processes, such as hypoxia/ischemia, inflammation, intoxications, and carcinogenesis. Both classes of diseases lead to cellular energetic depression (CED), which is characterized by decreased cytosolic phosphorylation potential that suppresses the cell’s ability to do work and control the intracellular Ca2+ homeostasis and its redox state. If progressing, CED leads to cell death, whose type is linked to the functional status of the mitochondria. In the case of limited deterioration, when some amounts of ATP can still be generated due to oxidative phosphorylation (OXPHOS), mitochondria launch the apoptotic cell death program by release of cytochrome c. Following pronounced CED, cytoplasmic ATP levels fall below the thresholds required for processing the ATP-dependent apoptotic cascade and the cell dies from necrosis. Both types of death can be grouped together as a mitochondrial cell death (MCD). However, there exist multiple adaptive reactions aimed at protecting cells against CED. In this context, a metabolic shift characterized by suppression of OXPHOS combined with activation of aerobic glycolysis as the main pathway for ATP synthesis (Warburg effect) is of central importance. Whereas this type of adaptation is sufficiently effective to avoid CED and to control the cellular redox state, thereby ensuring the cell survival, it also favors the avoidance of apoptotic cell death. This scenario may underlie uncontrolled cellular proliferation and growth, eventually resulting in carcinogenesis
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