Absolute Configuration and Selective Trypanocidal Activity of Gaudichaudianic Acid Enantiomers

Gaudichaudianic acid, a prenylated chromene isolated from Piper gaudichaudianum, has been described as a potent trypanocidal compound against the Y-strain of Trypanosoma cruzi. We herein describe its isolation as a racemic mixture followed by enantiomeric resolution using chiral HPLC and determination of the absolute configuration of the enantiomers as (+)-S and (-)-R by means of a combination of electronic and vibrational circular dichroism using density functional theory calculations. Investigation of the EtOAc extract of the roots, stems, and leaves from both adult specimens and seedlings of P. gaudichaudianum revealed that gaudichaudianic acid is biosynthesized as a racemic mixture from the seedling stage onward. Moreover, gaudichaudianic acid was found exclusively in the roots of seedlings, while it is present in all organs of the adult plant. Trypanocidal assays indicated that the (+)-enantiomer was more active than its antipode. Interestingly, mixtures of enantiomers stowed a synergistic effect, with the racemic mixture being the most active.

Entre júbilo e ruína: a perspectiva trágica de Nietzsche

It is investigating why reason Nietzsche affirms, in 1888, when revises his work (Ecce Homo), that to be exactly with The Birth of Tragedy it will be necessary to forget some things , and, in spite of, insist, in the same writing, in naming himself the first tragic philosopher - that is, the opposite and antipode of a pessimistic philosopher . Nietzsche elaborates in The Birth of Tragedy a theory about tragic starting from the opposition and complementarity among Apollo and Dionysian, rationalism and instinct, and in the refusal of the pessimistic perspective. The objective of the dissertation is to discuss how the theory of tragedy modifies due to the rupture with the inspiring of the first moment of the nietzschian philosophy, Schopenhauer and Wagner - maybe the such things to be forgotten about The Birth of Tragedy - and the implications of this rupture, that transforms the philosophy of Nietzsche in dissident of the metaphysical tradition. Like this, it is noticed that there is more continuity than estrangement in what concerns to the definition of tragic, just announced in 1871. By the sentence of the eternal return to the concept of will of power Nietzsche elaborates a tragic perspective, marked by the Dionysian celebration of the life, also acted through the pessimism dionisiac , defined in Gaya Science's § 370 (1881-2), and of the sentence of the love fate, enunciated in the §276 of the same work; all those concepts, discussed in this research, concentrate, decisively, the acceptance idea and statement of life, or more precisely, the decline of the tragic hero, between joy and ruin

Absolute Configuration and Selective Trypanocidal Activity of Gaudichaudianic Acid Enantiomers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Albendazole sulfoxide enantiomers: Preparative chiral separation and absolute stereochemistry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Immobilization of marine fungi on silica gel, silica xerogel and chitosan for biocatalytic reduction of ketones

The scanning electron microscopy (SEM) analysis showed that whole living hyphal of marine fungi Aspergillus sclerotiorum CBMAI 849 and Penicillium citrinum CBMAI 1186 were immobilized on support matrices of silica gel, silica xerogel and/or chitosan. P. citrinum immobilized on chitosan catalyzed the quantitative reduction of 1-(4-methoxyphenyl)-ethanone (1) to the enantiomer (S)-1-(4-methoxyphenyl)-ethanol (3b), with excellent enantioselectivity (ee > 99%, yield = 95%). Interestingly, ketone 1 was reduced with moderate selectivity and conversion to alcohol 3b (ee = 69%, c 40%) by the free mycelium of P. citrinum. This free mycelium of P. citrinum catalyzed the production of the (R)-alcohol 3a, the antipode of the alcohol produced by the immobilized cells. P. citrinum immobilized on chitosan also catalyzed the bioreduction of 2-chloro-1-phenylethanone (2) to 2-chloro-1-phenylethanol (4a,b), but in this case without optical selectivity. These results showed that biocatalytic reduction of ketones by immobilization hyphal of marine fungi depends on the xenobiotic substrate and the support matrix used. (c) 2012 Elsevier B.V. All rights reserved.

The massless two-loop two-point function and zeta functions in counterterms of Feynman diagrams

The main part of this thesis describes a method of calculating the massless two-loop two-point function which allows expanding the integral up to an arbitrary order in the dimensional regularization parameter epsilon by rewriting it as a double Mellin-Barnes integral. Closing the contour and collecting the residues then transforms this integral into a form that enables us to utilize S. Weinzierl's computer library nestedsums. We could show that multiple zeta values and rational numbers are sufficient for expanding the massless two-loop two-point function to all orders in epsilon. We then use the Hopf algebra of Feynman diagrams and its antipode, to investigate the appearance of Riemann's zeta function in counterterms of Feynman diagrams in massless Yukawa theory and massless QED. The class of Feynman diagrams we consider consists of graphs built from primitive one-loop diagrams and the non-planar vertex correction, where the vertex corrections only depend on one external momentum. We showed the absence of powers of pi in the counterterms of the non-planar vertex correction and diagrams built by shuffling it with the one-loop vertex correction. We also found the invariance of some coefficients of zeta functions under a change of momentum flow through these vertex corrections.

The Protection and Promotion of Cultural Diversity at the International Level

The Convention on the Protection and Promotion of the Diversity of Cultural Expressions, adopted under the auspices of the United Nations Educational, Cultural and Scientific Organization (UNESCO) in 2005, entered into force on 18 March 2007 after an incredibly swift ratification process. The Convention is the culmination of multiple-track efforts that spread over many years with the objective of providing a binding instrument for the protection and promotion of cultural diversity at the international level. These efforts, admirable as they may be, are not however isolated undertakings of goodwill, but a reaction to economic globalisation, whose advancement has been significantly furthered by the emergence of enforceable multilateral trade rules. These very rules, whose bearer is the World Trade Organization (WTO), have been perceived as the antipode to "culture" and have commanded the formulation of counteracting norms that may sufficiently "protect" and "promote" it. Against this backdrop of institutional tension and fragmentation, the present chapter explicates the emergence of the concept of cultural diversity on the international policy- and law-making scene and its legal dimensions given by the new UNESCO Convention. It critically analyses the Convention's provisions, in particular the rights and obligations of the State Parties, and asks whether indeed the UNESCO Convention provides a sufficient and appropriate basis for the protection and promotion of a thriving and diverse cultural environment.

Nd and Pb isotopes in ferromanganese crusts

The intensity of North Atlantic Deep Water (NADW) production has been one of the most important parameters controlling the global thermohaline ocean circulation system and climate. Here we present a new approach to reconstruct the overall strength of NADW export from the North Atlantic to the Southern Ocean over the past 14 Myr applying the deep water Nd and Pb isotope composition as recorded by ferromanganese crusts and nodules. We present the first long-term Nd and Pb isotope time series for deep Southern Ocean water masses, which are compared with previously published time series for NADW from the NW Atlantic Ocean. These data suggest a continuous and strong export of NADW, or a precursor of it, into the Southern Ocean between 14 and 3 Ma. An increasing difference in Nd and Pb isotope compositions between the NW Atlantic and the Southern Ocean over the past 3 Myr gives evidence for a progressive overall reduction of NADW export since the onset of Northern Hemisphere glaciation (NHG). The Nd isotope data allow us to assess at least semiquantitatively that the amount of this reduction has been in the range between 14 and 37% depending on location.