The 2:1 cycloadducts from [3+2] 1,3-dipolar cycloaddition of nitrile oxide and vinylacetic acid. Synthesis and liquid crystal behaviour

Four liquid crystals (LC) 3,7a-bis(4-alkyloxyphenyl)-7,7a-dihydro-6H-isoxazolo[2,3-d][1,2,4]oxadiazol-6-yl)acetic acid (7a-d) were synthesised and the mesomorphic behaviour reported. The LCs were characterised as 2: 1 bisadducts, which were obtained from a double [3+2] 1,3-dipolar cycloaddition. In the first step, the cycloaddition of 4-alkyloxyphenylnitrile oxide (4a-d) and vinylacetic acid (5) gave the initial unobserved 1:1 cycloadducts 2-[3-(4-alkyloxyphenyl)-4,5-dihydroisoxazol-5-yl]acetic acid (6a-d). In the second step, the addition of a second equivalent of 4 to 6 yielded the 2: 1 bisadducts 7a-d without any traces of 6. All compounds 7a-d were unstable during the transition from the mesophase to the isotropic state upon first heating as evidenced by the large peaks in the differential scanning calorimetry traces. Due to the chemical instability of the compounds upon heating, the transition temperature related to the smectic C to smectic A transitions was acquired by means of an image processing method. X-Ray diffraction experiments were also used to analyse the liquid-crystalline phases. A theoretical calculation was performed using density functional theory (DFT) methods at the PBE1PBE/6-311+G(2d,p) level (with solvent effect) in order to get information about the energetic profile of the 2: 1 cycloaddition. DFT studies revealed that the cycloaddition process is controlled by the HOMO(dipolarophile) - LUMO(1,3-dipole), and that the double [3+2] 1,3-dipolar cycloaddition reaction is quite possible.

Electron collisions with the HCOOH...(H2O)n (n=1, 2 and 3) complexes in liquid phase: the influence on the π* shape resonance of formic acid

In this conference we report cross sections for elastic collisions of low-energy electrons with the HCOOH…(H2O)n complexes, with n = 1, 2 and 3. The scattering cross sections were computed with the Schwinger multichannel method [K. Takatsuka and V. McKoy, Phys. Rev. A 24 , 2473 (1981); Phys. Rev. A 30 , 1734 (1984)] with pseudopotentials [M. H. F. Bettega, L. G. Ferreira, and M. A. P. Lima, Phys. Rev. A 47, 1111 (1993)] in the static-exchange and static-exchange plus polarization approximations, for energies from 0.5 eV to 6 eV. We considered some diÆerent hydrogen-bonded structures for the complexes that were generated with classical Monte Carlo simulations [K. Coutinho and S. Canuto, J. Chem. Phys. 113, 9132, (2000)]. The aim of this work is to investigate the effect of the surrounding water molecules on the π* shape resonance of the solute. Previous theoretical and experimental studies carried out in the gas phase reported a π* state for HCOOH at around 1.9 eV. For the n = 1 case and for all complexes, the stabilization of the resonance was observed (it appears at lower energy compared to the value obtained in the gas phase), as reported previously for the CH2O…H2O complexes [T. C. Freitas, M. A. P. Lima, S. Canuto, and M. H. F. Bettega, Phys. Rev. A 80, 062710 (2009)]. This result indicates that the presence of the solvent may affect the processes related to the π* state, such as the molecular dissociation by electron impact. For the n = 2 case we have observed both stabilization and destabilization of the π* resonance, that is associated with the hydrogen bond donor or acceptor role of the water molecules in the complexes. For the n = 3 case, preliminary static-exchange results show the stabilization of the π* state. We propose an explanation of the stabilization/destabilization of the π* state in terms of the polarization of the solute due to the surrounding water molecules and the net charge in the solute.

Relative CO(2)/NH(3) selectivities of mammalian aquaporins 0-9

Previous work showed that aquaporin 1 (AQP1), AQP4-M23, and AQP5 each has a characteristic CO(2)/NH(3) and CO(2)/H(2)O permeability ratio. The goal of the present study is to characterize AQPs 0-9, which traffic to the plasma membrane when heterologously expressed in Xenopus oocytes. We use video microscopy to compute osmotic water permeability (P(f)) and microelectrodes to record transient changes in surface pH (ΔpH(S)) caused by CO(2) or NH(3) influx. Subtracting respective values for day-matched, H(2)O-injected control oocytes yields the channel-specific values P(f)* and ΔpH(S)*. We find that P(f)* is significantly >0 for all AQPs tested except AQP6. (ΔpH(S)*)(CO(2)) is significantly >0 for AQP0, AQP1, AQP4-M23, AQP5, AQP6, and AQP9. (ΔpH(S)*)(NH(3)) is >0 for AQP1, AQP3, AQP6, AQP7, AQP8, and AQP9. The ratio (ΔpH(S)*)(CO(2))/P(f)* falls in the sequence AQP6 (∞) > AQP5 > AQP4-M23 > AQP0 ≅ AQP1 ≅ AQP9 > others (0). The ratio (ΔpH(S)*)(NH(3))/P(f)* falls in the sequence AQP6 (∞) > AQP3 ≅ AQP7 ≅ AQP8 ≅ AQP9 > AQP1 > others (0). Finally, the ratio (ΔpH(S)*)(CO(2))/(-ΔpH(S)*)(NH(3)) falls in the sequence AQP0 (∞) ≅ AQP4-M23 ≅ AQP5 > AQP6 > AQP1 > AQP9 > AQP3 (0) ≅ AQP7 ≅ AQP8. The ratio (ΔpH(S)*)(CO(2))/(-ΔpH(S)*)(NH(3)) is indeterminate for both AQP2 and AQP4-M1. In summary, we find that mammalian AQPs exhibit a diverse range of selectivities for CO(2) vs. NH(3) vs. H(2)O. As a consequence, by expressing specific combinations of AQPs, cells could exert considerable control over the movements of each of these three substances

Local structure around Fe ions on multiferroic Pb(Fe1/2Nb1/2)O-3 ceramics probed by x-ray absorption spectroscopy

Local structure around Fe ions on Pb(Fe1/2Nb1/2)O-3 ceramics was probed by x-ray absorption spectroscopy in order to settle the controversies about its structure. It is observed that the shell structure around Fe atoms exhibits a monoclinic local symmetry at 130 and 230 K, tetragonal local symmetry at room temperature, and cubic local symmetry at 410 K. Independently of the coordination, temperature, or symmetry, Fe-O mean bond-length does not vary significantly. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4709490]

On the search for potential anti-Trypanosoma cruzi drugs: Synthesis and biological evaluation of 2-hydroxy-3-methylamino and 1,2,3-triazolic naphthoquinoidal compounds obtained by click chemistry reactions

Five 2-hydroxy-3-substituted-aminomethyl naphthoquinones, nine 1,2,3-triazolic para-naphthoquinones, five nor-beta-lapachone-based 1,2,3-triazoles, and several other naphthoquinonoid compounds were synthesized and evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease, continuing our screening program for new trypanocidal compounds. Among all the substances, 16-18, 23, 25-29 and 30-33 were herein described for the first time and fifteen substances were identified as more potent than the standard drug benznidazole, with IC50/24 h values in the range of 10.9-101.5 mu M. Compounds 14 and 19 with Selectivity Index of 18.9 and 6.1 are important structures for further studies. (C) 2012 Elsevier Masson SAS. All rights reserved.

Magnetic and optical investigation of 40SiO(2)center dot 30Na(2)O center dot 1Al(2)O(3)center dot(29-x) B2O3 center dot xFe(2)O(3) glass matrix

Samples of 40SiO(2)center dot 30Na(2)O center dot 1Al(2)O(3)center dot(29 - x)B2O3 center dot xFe(2)O(3) (mol%), with 0.0 <= x <= 17.5, were prepared by the fusion method and investigated by electron paramagnetic resonance (EPR), optical absorption (OA) and Mossbauer spectroscopy (MS). The EPR spectra of the as-synthesized samples exhibit two well-defined EPR signals around g = 4.27 and g = 2.01 and a visible EPR shoulder around g = 6.4, assigned to isolated Fe3+ ion complexes (g = 4.27 and g = 6.4) and Fe3+-based clusters (g = 2.01). Analyses of both EPR line intensity and line width support the model picture of Fe3+-based clusters built in from two sources of isolated ions, namely Fe2+ and Fe3+; the ferrous ion being used to build in iron-based clusters at lower x-content (below about x = 2.5%) whereas the ferric ion is used to build in iron-based clusters at higher x-content (above about x = 2.5%). The presence of Fe2+ ions incorporated within the glass template is supported by OA data with a strong band around 1100 nm due to the spin-allowed E-5(g)-T-5(2g) transition in an octahedral coordination with oxygen. Additionally, Mossbauer data (isomer shift and quadrupole splitting) confirm incorporation of both Fe2+ and Fe3+ ions within the template, more likely in tetrahedral-like environments. We hypothesize that ferrous ions are incorporated within the glass template as FeO4 complex resulting from replacing silicon in non-bridging oxygen (SiO3O-) sites whereas ferric ions are incorporated as FeO4 complex resulting from replacing silicon in bridging-like oxygen silicate groups (SiO4). (C) 2012 Elsevier Masson SAS. All rights reserved.

Narrativa da memória Epopéia Paulista

O presente estudo aborda as relações existentes entre a memória e a arte, registradas atravésde monumentos arquitetônicos na cidade de São Paulo, especialmente, no âmbito da artecontemporânea. Elege como instrumental de pesquisa a história da arte e seus desdobramentosestéticos, tendo como foco de análise a "poética de memórias" de Maria Bonomi uma das mais importantes artistas do cenário nacional. O painel Epopéia Paulista, construído a partirde ateliê-residência, em abril de 2004, no espaço expositivo do Museu de Arte Contemporâneada Universidade de São Paulo (MAC USP) e que hoje se encontra no corredor de ligaçãoentre o Metrô e a Companhia Paulista de Trens Metropolitanos (na Estação da Luz) servecomo obra-referência na criação e no processo de narrativas de memórias de diversas etniasem São Paulo

Increased clopidogrel response is associated with ABCC3 expression: A pilot study

Background: The aim of this study was investigate the relationship between ABCB1 and ABCC3 gene expressions in peripheral blood cells (PBC) and the response to clopidogrel in patients with coronary arterial disease (CAD). Methods: Twenty-six male CAD patients (50-70 years) under treatment with clopidogrel (75 mg/day) for at least 5 days were selected. Blood samples were obtained to evaluate platelet reactivity and ABCB1 and ABCC3 mRNA expression. Platelet reactivity was measured in P2Y12 Reaction Units (PRU) using VerifyNow. RNA was extracted from PBC and mRNA levels were measured by qPCR, using GAPD as a reference gene. Results: Platelet response to clopidogrel was categorized in to PRU quartiles. Individuals with PRU values within the first quartile (Q1, <151 units) were considered good responders, while those who had PRU within the fourth quartile (Q4. PRU>260) were considered non-responders. ABCC3 was 1.7 times more expressed in Q4 than in Q1 PRU group (p=0.048). Moreover, CAD patients with low ABCC3 expression (Qe1, <2.5x10(-3)) had higher probability to have a good response to clopidogrel (OR: 18.00, 95%CI: 1.90-169.99, p=0.001). Univariate linear regression analysis demonstrated that low ABCC3 mRNA expression contributed with a reduction of 73 PRU in relation to the patients with expression value higher than 2.5x10(-3) (p=0.027). Neither ABCB1 mRNA levels nor clinical variables studied influenced PRU values. Conclusions: Low ABCC3 mRNA expression in peripheral blood cells is associated with increased clopidogrel response, but further studies are needed to describe the functional relationship of clopidogrel with the ABCC3. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Histopathological evaluation and risk factors related to the development of pouchitis in patients with ileal pouches for ulcerative colitis

OBJECTIVE: Many changes in mucosal morphology are observed following ileal pouch construction, including colonic metaplasia and dysplasia. Additionally, one rare but potential complication is the development of adenocarcinoma of the reservoir. The aim of this study was to evaluate the most frequently observed histopathological changes in ileal pouches and to correlate these changes with potential risk factors for complications. METHODS: A total of 41 patients were enrolled in the study and divided into the following three groups: a non-pouchitis group (group 1) (n = 20; 8 males; mean age: 47.5 years) demonstrating optimal outcome; a pouchitis without antibiotics group (group 2) (n = 14; 4 males; mean age: 47 years), containing individuals with pouchitis who did not receive treatment with antibiotics; and a pouchitis plus antibiotics group (group 3) (n = 7; 3 males; mean age: 41 years), containing those patients with pouchitis who were administered antibiotics. Ileal pouch endoscopy was performed, and tissue biopsy samples were collected for histopathological analysis. RESULTS: Colonic metaplasia was found in 15 (36.6%) of the 41 patients evaluated; of these, five (25%) were from group 1, eight (57.1%) were from group 2, and two (28.6%) were from group 3. However, no correlation was established between the presence of metaplasia and pouchitis (p = 0.17). and no differences in mucosal atrophy or the degree of chronic or acute inflammation were observed between groups 1, 2, and 3 (p > 0.45). Moreover, no dysplasia or neoplastic changes were detected. However, the degree of mucosal atrophy correlated well with the time of postoperative follow-up (p = 0.05). CONCLUSIONS: The degree of mucosal atrophy, the presence of colonic metaplasia, and the degree of acute or chronic inflammation do not appear to constitute risk factors for the development of pouchitis. Moreover, we observed that longer postoperative follow-up times were associated with greater degrees of mucosal atrophy.

Mycobacterium Bovis como agente causal da tuberculose humana

O Mycobacterium bovis incluído no complexo Mycobacterium tuberculosis pode infectar várias espécies de animais domésticos e silvestres. Embora acometa principalmente animais da espécie bovina também pode infectar outros mamíferos e inclusive os seres humanos, nos quais determina um quadro clínico indistinguível do causado pelo M. tuberculosis. Em diversos países desenvolvidos, devido à aplicação de rigorosas medidas de controle e consequente redução da prevalência da tuberculose bovina, bem como de infecções em outras espécies de animais pelo M. bovis houve em decréscimo dos níveis de ocorrência desta patologia e o tema passou a ser considerado de menor importância. No entanto, nos países em desenvolvimento, a infecção por M. bovis ainda representa um importante risco para a saúde pública, pois tem sido observada nos animais domésticos, silvestres e em seres humanos. O presente trabalho analisa a importância da infecção pelo Mycobacterium bovis em termos de saúde pública.

Layer-by-Layer assembled cobalt ferrite nanoparticles for chemical sensing

Ultra-thin (thicknesses of 50-90 nm) nanocomposite films of cobalt ferrite nanoparticles (np-CoFe2O4, 18 nm in diameter) and polyelectrolytes (doped polyaniline-PANI, poly-3,4-ethylenedioxy thiophene: polystyrene sulfonic acid-PEDOT:PSS, and sulfonated lignin-SL) are assembled layer-by-layer onto interdigitated microelectrodes aiming at to create novel nanostructured sensoactive materials for liquid media chemical sensors. The nanocomposites display a distinctive globular morphology with nanoparticles densely-packed while surrounded by polyelectrolytes. Due to the presence of np-CoFe2O4 the nanocomposites display low electrical conductivity according to impedance data. On the other hand, this apparent shortcoming turns such nanocomposites much more sensitive to the presence of ions in solution than films made exclusively of conducting polyelectrolytes. For example, the electrical resistance of np-CoFe2O4/PEDOT:PSS and PANI/SL/np-CoFe2O4/SL architectures has a 10-fold decrease when they are immersed in 20 mmol. L-1 NaCl solution. Impedance spectra fitted with the response of an equivalent circuit model suggest that the interface created between nanoparticles and polyelectrolytes plays a major role on the nanocomposites electrical/dielectrical behavior. Since charge transport is sensitive to nanoparticle-polyelectrolyte interfaces as well as to the physicochemical conditions of the environment, the np-CoFe2O4-based nanocomposites can be used as sensing elements in chemical sensors operated under ac regime and room temperature.