Neoliberalismo, políticas públicas e desigualdade: Uma análise principalmente do Brasil

In this paper, we intend to identify the main aspects and interests of neoliberal politics and its effort to use the State as an instrument to benefit financial capital, equipping it and equating it with the private company. Our objective is to show that capitalism, with its cyclical economic and social crises, does not offer alternatives to overcome unemployment, as well as the inequality that spreads in all countries. In the financial sector and in large companies, there was an unprecedented policy of opening borders with the reduction of labor and social rights. However, this policy must be analyzed and considered.Pretendemos identificar os principais aspectos e interesses da política Neoliberal e seu esforço em utilizar o Estado como um instrumento para beneficiar o capital financeiro, o aparelhando e o equiparado à Empresa privada. Nosso objetivo é mostrar que o capitalismo, com suas crises econômicas e sociais cíclicas, não oferece alternativas para superar o desemprego, assim como, a desigualdade que se espalha em todos os países. No setor financeiro e nas grandes empresas houve uma política sem precedentes de abertura de fronteiras com a redução dos direitos trabalhistas e sociais. Entretanto, essa política deve ser analisada e ponderada

Investigation of a passive control system for limiting cavitation inside turbomachinery under different operating conditions

Abstract Herein, a new passive control system for limiting cavitation inside turbomachinery has been applied to a NACA0009 hydrofoil. The basic idea is to introduce slots nearby its leading edge, connecting pressure and suction sides of the hydrofoil, in order to increase locally the pressure on its suction side and to prevent cavitation from developing. The cavitating flow developed around a two-dimensional hydrofoil is here considered since it is an archetype of cavitation nearby the leading edges of the impeller vanes. Thus, the flow field developed at the leading edge of both the original and modified hydrofoil has been studied at different angles of attack in order to reproduce a wide range of operating conditions that occur inside turbomachinery. Eventually, a comparison of their performance in terms of polars (C L and C D ) and vapour volume fractions (α v ) is performed

A Substrate-induced Switch in the Reaction Mechanism of a Thermophilic Esterase KINETIC EVIDENCES AND STRUCTURAL BASIS

The reaction mechanism of the esterase 2 (EST2) from Alicyclobacillus acidocaldarius was studied at the kinetic and structural level to shed light on the mechanism of activity and substrate specificity increase previously observed in its double mutant M211S/R215L. In particular, the values of kinetic constants (k1, k(-1), k2, and k3) along with activation energies (E1, E(-1), E2, and E3) were measured for wild type and mutant enzyme. The previously suggested substrate-induced switch in the reaction mechanism from kcat=k3 with a short acyl chain substrate (p-nitrophenyl hexanoate) to kcat=k2 with a long acyl chain substrate (p-nitrophenyl dodecanoate) was validated. The inhibition afforded by an irreversible inhibitor (1-hexadecanesulfonyl chloride), structurally related to p-nitrophenyl dodecanoate, was studied by kinetic analysis. Moreover the three-dimensional structure of the double mutant bound to this inhibitor was determined, providing essential information on the enzyme mechanism. In fact, structural analysis explained the observed substrate-induced switch because of an inversion in the binding mode of the long acyl chain derivatives with respect to the acyl- and alcohol-binding sites

A Late-Stage Synthetic Approach to Lanthionine-Containing Peptides via S-Alkylation on Cyclic Sulfamidates Promoted by Molecular Sieves

A one-pot, high-yield procedure for synthesizing lanthionine-containing peptides was developed. It relies on the S-alkylation of cysteine-containing peptides with chiral cyclic sulfamidates. The key feature of this approach is the use of mild reaction conditions (only activated molecular sieves are employed as the catalyst), leading to good chemoselectivity and excellent stereochemical control. The potential of the new methodology has been investigated by synthesizing the thioether ring of a natural lantibiotic, Haloduracin \u3b2

Gadolinium-Decorated Silica Microspheres as Redox-Responsive MRI Probes for Applications in Cell Therapy Follow-Up

The redox microenvironment within a cell graft can be considered as an indicator to assess whether the graft is metabolically active or hypoxic. We present a redox-responsive MRI probe based on porous silica microparticles whose surface has been decorated with a Gd-chelate through a disulphide bridge. Such microparticles are designed to be interspersed with therapeutic cells within a biocompatible hydrogel. The onset of reducing conditions within the hydrogel is paralleled by an increased clearance of Gd, that can be detected by MRI

Crystallization and preliminary X-ray diffraction studies of a D

A 10-mer duplex formed between a PNA containing a `chiral box' of three adjacent d-Lys-based monomers and its complementary DNA strand has been crystallized for the first time. Crystals have been obtained using PEG 8000 as precipitant and cacodylate at pH 6.3 as buffer. The crystals belong to the space group P31 or to its enantiomorph P32, with unit-cell parameters a = b = 35.00, c = 35.91 Å. A complete data set has been collected at the synchrotron source Elettra in Trieste to 1.85 Å resolution, using a single frozen crystal

Controlled assembly of SNAP-PNA-fluorophore systems on DNA templates to produce fluorescence resonance energy transfer

The SNAP protein is a widely used self-labeling tag that can be used for tracking protein localization and trafficking in living systems. A model system providing controlled alignment of SNAP-tag units can provide a new way to study clustering of fusion proteins. In this work, fluorescent SNAP-PNA conjugates were controllably assembled on DNA frameworks forming dimers, trimers, and tetramers. Modification of peptide nucleic acid (PNA) with the O6-benzyl guanine (BG) group allowed the generation of site-selective covalent links between PNA and the SNAP protein. The modified BG-PNAs were labeled with fluorescent Atto dyes and subsequently chemo-selectively conjugated to SNAP protein. Efficient assembly into dimer and oligomer forms was verified via size exclusion chromatography (SEC), electrophoresis (SDS-PAGE), and fluorescence spectroscopy. DNA directed assembly of homo- and hetero-dimers of SNAP-PNA constructs induced homo- and hetero-FRET, respectively. Longer DNA scaffolds controllably aligned similar fluorescent SNAP-PNA constructs into higher oligomers exhibiting homo-FRET. The combined SEC and homo-FRET studies indicated the 1:1 and saturated assemblies of SNAP-PNA-fluorophore:DNA formed preferentially in this system. This suggested a kinetic/stoichiometric model of assembly rather than binomially distributed products. These BG-PNA-fluorophore building blocks allow facile introduction of fluorophores and/or assembly directing moieties onto any protein containing SNAP. Template directed assembly of PNA modified SNAP proteins may be used to investigate clustering behavior both with and without fluorescent labels which may find use in the study of assembly processes in cells

Chiral introduction of positive charges to PNA for double-duplex invasion to versatile sequences

Invasion of two PNA strands to double-stranded DNA is one of the most promising methods to recognize a predetermined site in double-stranded DNA (PNA = peptide nucleic acid). In order to facilitate this ‘double-duplex invasion’, a new type of PNA was prepared by using chiral PNA monomers in which a nucleobase was bound to the α-nitrogen of N-(2-aminoethyl)-d-lysine. These positively charged monomer units, introduced to defined positions in Nielsen's PNAs (poly[N-(2-aminoethyl)glycine] derivatives), promoted the invasion without impairing mismatch-recognizing activity. When pseudo-complementary nucleobases 2,6-diaminopurine and 2-thiouracil were bound to N-(2-aminoethyl)-d-lysine, the invasion successfully occurred even at highly G–C-rich regions [e.g. (G/C)7(A/T)3 and (G/C)8(A/T)2] which were otherwise hardly targeted. Thus, the scope of sequences available as the target site has been greatly expanded. In contrast with the promotion by the chiral PNA monomers derived from N-(2-aminoethyl)-d-lysine, their l-isomers hardly invaded, showing crucial importance of the d-chirality. The promotion of double-duplex invasion by the chiral (d) PNA monomer units was ascribed to both destabilization of PNA/PNA duplex and stabilization of PNA/DNA duplexes

Backbone-base inclination as a fundamental determinant of nucleic acid self- and cross-pairing

The crystal structure of the duplex formed by oligo(2′,3′-dideoxy-β-d-glucopyranosyl)nucleotides (homo-DNA) revealed strongly inclined backbone and base-pair axes [Egli,M., Pallan,P.S., Pattanayek,R., Wilds,C.J., Lubini,P., Minasov,G., Dobler,M., Leumann,C.J. and Eschenmoser,A. (2006) Crystal structure of homo-DNA and nature's choice of pentose over hexose in the genetic system. J. Am. Chem. Soc., 128, 10847–10856]. This inclination is easily perceived because homo-DNA exhibits only a modest helical twist. Conversely, the tight coiling of strands conceals that the backbone-base inclinations for A- (DNA and RNA) and B-form (DNA) duplexes differ considerably. We have defined a parameter ηB that corresponds to the local inclination between sugar-phosphate backbone and base plane in nucleic acid strands. Here, we show its biological significance as a predictive measure for the relative strand polarities (antiparallel, aps, or parallel, ps) in duplexes of DNA, RNA and artificial nucleic acid pairing systems. The potential of formation of ps duplexes between complementary 16-mers with eight A and U(T) residues each was investigated with DNA, RNA, 2′-O-methylated RNA, homo-DNA and p-RNA, the ribopyranosyl isomer of RNA. The thermodynamic stabilities of the corresponding aps duplexes were also measured. As shown previously, DNA is capable of forming both ps and aps duplexes. However, all other tested systems are unable to form stable ps duplexes with reverse Watson–Crick (rWC) base pairs. This observation illustrates the handicap encountered by nucleic acid systems with inclinations ηB that differ significantly from 0° to form a ps rWC paired duplex. Accordingly, RNA with a backbone-base inclination of −30°, pairs strictly in an aps fashion. On the other hand, the more or less perpendicular orientation of backbone and bases in DNA allows it to adopt a ps rWC paired duplex. In addition to providing a rationalization of relative strand polarity with nucleic acids, the backbone-base inclination parameter is also a determinant of cross-pairing. Thus, systems with strongly deviating ηB angles will not pair with each other. Nucleic acid pairing systems with significant backbone-base inclinations can also be expected to display different stabilities depending on which terminus carries unpaired nucleotides. The negative inclination of RNA is consistent with the higher stability of duplexes with 3′- compared to those with 5′-dangling ends