Multi-stage evolution of a sub-aerial volcanic ridge over the last 1.3 Myr: S. Jorge Island, Azores Triple Junction

New K/Ar dating and geochemical analyses have been carried out on the WNW-ESE elongated oceanic island of S. Jorge to reconstruct the volcanic evolution of a linear ridge developed close to the Azores triple junction. We show that S. Jorge sub-aerial construction encompasses the last 1.3 Myr, a time interval far much longer than previously reported. The early development of the ridge involved a sub-aerial building phase exposed in the southeast end of the island and now constrained between 1.32 +/- 0.02 and 1.21 +/- 0.02 Ma. Basic lavas from this older stage are alkaline and enriched in incompatible elements, reflecting partial melting of an enriched mantle source. At least three differentiation cycles from alkaline basalts to mugearites are documented within this stage. The successive episodes of magma rising, storage and evolution suggest an intermittent reopening of the magma feeding system, possibly due to recurrent tensional or trans-tensional tectonic events. Present data show a gap in sub-aerial volcanism before a second main ongoing building phase starting at about 750 ka. Sub-aerial construction of the S. Jorge ridge migrated progressively towards the west, but involved several overlapping volcanic episodes constrained along the main WNW-ESE structural axis of the island. Malic magmas erupted during the second phase have been also generated by partial melting of an enriched mantle source. Trace element data suggest, however, variable and lower degrees of partial melting of a shallower mantle domain, which is interpreted as an increasing control of lithospheric deformation on the genesis and extraction of primitive melts during the last 750 kyr. The multi-stage development of the S. Jorge volcanic ridge over the last 1.3 Myr has most likely been greatly influenced by regional tectonics, controlled by deformation along the diffuse boundary between the Nubian and the Eurasian plates, and the increasing effect of sea-floor spreading at the Mid-Atlantic Ridge.

Palaeomagnetic study of a subaerial volcanic ridge (Sao Jorge Island, Azores) for the past 1.3 Myr: evidence for the Cobb Mountain Subchron, volcano flank instability and tectonomagmatic implications

We present a palaeomagnetic study on 38 lava flows and 20 dykes encompassing the past 1.3 Myr on S. Jorge Island (Azores ArchipelagoNorth Atlantic Ocean). The sections sampled in the southeastern and central/western parts of the island record reversed and normal polarities, respectively. They indicate a mean palaeomagnetic pole (81.3 degrees N, 160.7 degrees E, K= 33 and A95= 3.4 degrees) with a latitude shallower than that expected from Geocentric Axial Dipole assumption, suggesting an effect of non-dipolar components of the Earth magnetic field. Virtual Geomagnetic Poles of eight flows and two dykes closely follow the contemporaneous records of the Cobb Mountain Subchron (ODP/DSDP programs) and constrain the age transition from reversed to normal polarity at ca. 1.207 +/- 0.017 Ma. Volcano flank instabilities, probably related to dyke emplacement along an NNWSSE direction, led to southwestward tilting of the lava pile towards the sea. Two spatially and temporally distinct dyke systems have been recognized on the island. The eastern is dominated by NNWSSE trending dykes emplaced before the end of the Matuyama Chron, whereas in the central/western parts the eruptive fissures oriented WNWESE controlled the westward growth of the S. Jorge Island during the Brunhes Chron. Both directions are consistent with the present-day regional stress conditions deduced from plate kinematics and tectonomorphology and suggest the emplacement of dykes along pre-existing fractures. The distinct timing and location of each dyke system likely results from a slight shift of the magmatic source.

Syntheses, Molecular Structures, Electrochemical Behavior, Theoretical Study, and Antitumor Activities of Organotin(IV) Complexes Containing 1-(4-Chlorophenyl)-1-cyclopentanecarboxylato Ligands

The organotin(IV) compounds [Me2Sn(L)(2)] (1), [Et(2)sn(L)(2)] (2), [(Bu2Sn)-Bu-n(L)(2)] (3), [(n)Oct(2)Sn(L)(2)] (4), [Ph2Sn(L)(2)] (5), and [PhOSnL](6) (6) have been synthesized from the reactions of 1-(4-chlorophenyl)-1-cyclopentanecarboxylic acid (HL) with the corresponding diorganotin(IV) oxide or dichloride. They were characterized by IR and multinuclear NMR spectroscopies, elemental analysis, cyclic voltammetry, and, for 2, 3, 4 and 6, single crystal X-ray diffraction analysis. While 1-5 are mononuclear diorganotin (IV) compounds, the X-ray diffraction of 6 discloses a hexameric drumlike structure with a prismatic Sn6O6 core. All these complexes undergo irreversible reductions and were screened for their in vitro antitumor activities toward HL-60, BGC-823, Bel-7402, and KB human cancer cell lines. Within the mononuclear compounds, the most active ones (3, 5) are easiest to reduce (least cathodic reduction potentials), while the least active ones (1, 4) are the most difficult to reduce. Structural rearrangements (i.e., Sn-O bond cleavages and trans-to-cis isomerization) induced by reduction, which eventually can favor the bioactivity, are disclosed by theoretical/electrochemical studies.

Antifungal activity of Imidazolidin-4-ones of the antimalarial primaquine

The 5-Isopropyl-3-[4-(6-methoxy-quinolin-8-ylamino)-pentyl]-2,2-dimethyl-imidazolidin-4-one (ValPQacet) was sinthesized through acylation of the anti-malarial primaquine with α-valine and subsequent reaction of the resulting -aminoamide with propanone (Sheme 1).Imidazolidin-4-ones of the anti malarial primaquine are being sinthesized to develop new variants in order to improve more effective treatments against malaria . Recently it has been observed that primaquine derivates could have effect in a new kind of yeast . To study the fungicidal activity against Candida albicans, Candida tropicalis, Issatchenkia orientalis, Sacharomyces cerevisae, the ValPQacet was put in the form of the hydrochloride salt. The minimal inhibitory concentration (MIC) could be determined for all yeast in the concentration range assayed. Also was determined MIC’s of primaquine hydrochloride salt for all yeast, and this shows that the parent drug is less active than our compound. Further studies are being performed to determine viability and cellular injury with this drugs.

A Novel Short-Step Synthesis of New Xanthenedione Derivatives from the Cyclization of 3-Cinnamoyl-2-styrylchromones

Novel (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro-1 H-xanthene-1,9(2H)-diones are prepared by the cyclization of (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones efficiently catalyzed with boron tribromide. The (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones are obtained from the Baker–Venkataraman rearrangement of (E,E)-2-acetyl-1,3-phenylene bis(3-phenylacrylate), which is greatly improved under microwave irradiation.

A new strategy for the synthesis of 3-cinnamoyl-2-styrylchromones and their transformation into new xanthenodiones derivatives

23rd ISHC Congress will be held in Glasgow, Scotland from July 31 August 4, 2011.

CuxSnSx+1 (x = 2, 3) thin films grown by sulfurization of metallic precursors deposited by dc magnetron sputtering

We report the results of the growth of Cu-Sn-S ternary chalcogenide compounds by sulfurization of dc magnetron sputtered metallic precursors. Tetragonal Cu2SnS3 forms for a maximum sulfurization temperature of 350 ºC. Cubic Cu2SnS3 is obtained at sulfurization temperatures above 400 ºC. These results are supported by XRD analysis and Raman spectroscopy measurements. The latter analysis shows peaks at 336 cm-1, 351 cm-1 for tetragonal Cu2SnS3, and 303 cm-1, 355 cm-1 for cubic Cu2SnS3. Optical analysis shows that this phase change lowers the band gap from 1.35 eV to 0.98 eV. At higher sulfurization temperatures increased loss of Sn is expected in the sulphide form. As a consequence, higher Cu content ternary compounds like Cu3SnS4 grow. In these conditions, XRD and Raman analysis only detected orthorhombic (Pmn21) phase (petrukite). This compound has Raman peaks at 318 cm-1, 348 cm-1 and 295 cm-1. For a sulfurization temperature of 450 ºC the samples present a multi-phase structure mainly composed by cubic Cu2SnS3 and orthorhombic (Pmn21) Cu3SnS4. For higher temperatures, the samples are single phase and constituted by orthorhombic (Pmn21) Cu3SnS4. Transmittance and reflectance measurements were used to estimate a band gap of 1.60 eV. For comparison we also include the results for Cu2ZnSnS4 obtained using similar growth conditions.

Copper-organic frameworks assembled from in situ generated 5-(4-pyridyl) tetrazole building blocks: synthesis, structural features, topological analysis and catalytic oxidation of alcohols

Two new metal- organic compounds {[Cu-3(mu(3)-4-(p)tz)(4)(mu(2)-N-3)(2)(DMF)(2)](DMF)(2)}(n) (1) and {[Cu(4ptz) (2)(H2O)(2)]}(n) (2) {4-ptz = 5-(4-pyridyl)tetrazolate} with 3D and 2D coordination networks, respectively, have been synthesized while studying the effect of reaction conditions on the coordination modes of 4-pytz by employing the [2 + 3] cycloaddition as a tool for generating in situ the 5-substituted tetrazole ligands from 4-pyridinecarbonitrile and NaN3 in the presence of a copper(II) salt. The obtained compounds have been structurally characterized and the topological analysis of 1 discloses a topologically unique trinodal 3,5,6-connected 3D network which, upon further simplification, results in a uninodal 8-connected underlying net with the bcu (body centred cubic) topology driven by the [Cu-3(mu(2)-N-3)(2)] cluster nodes and mu(3)-4-ptz linkers. In contrast, the 2D metal-organic network in 2 has been classified as a uninodal 4-connected underlying net with the sql [Shubnikov tetragonal plane net] topology assembled from the Cu nodes and mu(2)-4-ptz linkers. The catalytic investigations disclosed that 1 and 2 act as active catalyst precursors towards the microwave-assisted homogeneous oxidation of secondary alcohols (1-phenylethanol, cyclohexanol, 2-hexanol, 3-hexanol, 2-octanol and 3-octanol) with tert-butylhydroperoxide, leading to the yields of the corresponding ketones up to 86% (TOF = 430 h(-1)) and 58% (TOF = 290 h(-1)) in the oxidation of 1-phenylethanol and cyclohexanol, respectively, after 1 h under low power ( 10 W) microwave irradiation, and in the absence of any added solvent or additive.

Greener Selective Cycloalkane Oxidations with Hydrogen Peroxide Catalyzed by Copper-5-(4-pyridyl)tetrazolate Metal-Organic Frameworks

Microwave assisted synthesis of the Cu(I) compound [Cu(µ4-4-ptz)]n [1, 4-ptz = 5-(4-pyridyl)tetrazolate] has been performed by employing a relatively easy method and within a shorter period of time compared to its sister compounds. The syntheses of the Cu(II) compounds [Cu3(µ3-4-ptz)4(µ2-N3)2(DMF)2]n∙(DMF)2n (2) and [Cu(µ2-4-ptz)2(H2O)2]n (3) using a similar method were reported previously by us. MOFs 1-3 revealed high catalytic activity toward oxidation of cyclic alkanes (cyclopentane, -hexane and -octane) with aqueous hydrogen peroxide, under very mild conditions (at room temperature), without any added solvent or additive. The most efficient system (2/H2O2) showed, for the oxidation of cyclohexane, a turnover number (TON) of 396 (TOF of 40 h−1), with an overall product yield (cyclohexanol and cyclohexanone) of 40% relative to the substrate. Moreover, the heterogeneous catalytic systems 1–3 allowed an easy catalyst recovery and reuse, at least for four consecutive cycles, maintaining ca. 90% of the initial high activity and concomitant high selectivity.

1,3-Diarilpropanos de Iryanthera paraensis e Iryanthera tricornis

Iryanthera paraensis e I. tricornis (Myristicaceae) contêm na madeira de seus troncos 1-(2', 4' - dihidroxifenil) -3- (4", 5"-metilenodoxi-2" -metoxifenil) -propano (1a 1-(2', 4' dihidroxifenil) -3-(3", 4" -metilenodioxifenil)-propano (1b) e 1-(4' -hidroxi -2'-metoxifenil) -3-(4"-hidroxi-3"-metoxifenil) -propano (1c). Apenas da primeira espécie se isolou adicionalmente 1-(2', 4'-dihidroxi-3' -metilfenil)-3-(4", 5"-metilenodioxi-2"- metoxifenil) -propano (1d) e 1-(2'-hidroxi-4'metoxifenil) -3-(3", 4"-metilenodioxifenil) -propano (1e). Dados espectroscópicos para a substância 1b, são descritos pela primeira vez.

Bacia 3 - Inventário Florestal Comercial

Inventário Florestal da Bacia 3 do projeto "Manejo Ecológico e Exploração da Floresta Tropical Úmida" para a avaliação dos potenciais quantitativo e qualitativo da cobertura florestal existente na área, com base em medições e observações em árvores com diâmetro a altura do peito (DAP) maior ou igual a 25 cm, de uma população florestal de 96 hectares. A área coberta pelo inventário é composta de 4 blocos de 24 hectares cada, os quais serão destinados às pesquisas de manejo da regeneração natural enriquecimento da floresta natural e regeneração artificial. Localiza-se entre o km 21 e o km 24 na margem esquerda da vicinal ZF-2, no Distrito Agropecuário da SUFRAMA (Superintendência da Zona Franca de Manaus).

Synthesis, antiangiogenesis evaluation and molecular docking studies of 1-Aryl-3-[(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas: Discovery of a new substitution pattern for type II VEGFR-2 Tyr kinase inhibitors

The synthesis and biological evaluation of novel 1-aryl-3-[2-, 3- or 4-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 3, 4 and 5 as VEGFR-2 tyrosine kinase inhibitors, are reported. The 1-aryl-3-[3-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 4a-4h, with the arylurea in the meta position to the thioether, showed the lowest IC50 values in enzymatic assays (10-206 nM), the most potent compounds 4d-4h (IC50 10-28 nM) bearing hydrophobic groups (Me, F, CF3 and Cl) in the terminal phenyl ring. A convincing rationalization was achieved for the highest potent compounds 4 as type II VEGFR-2 inhibitors, based on the simultaneous presence of: (1) the thioether linker and (2) the arylurea moiety in the meta position. For compounds 4, significant inhibition of Human Umbilical Vein Endothelial Cells (HUVECs) proliferation (BrdU assay), migration (wound-healing assay) and tube formation were observed at low concentrations. These compounds have also shown to increase apoptosis using the TUNEL assay. Immunostaining for total and phosphorylated (active) VEGFR-2 was performed by Western blotting. The phosphorylation of the receptor was significantly inhibited at 1.0 and 2.5 microM for the most promising compounds. Altogether, these findings point to an antiangiogenic effect in HUVECs.

Estado atual da determinação do carbono no solo I: em solos contendo de 0,2 a 4,0% de carbono

O presente trabalho relata os dados obtidos na determinação do carbono por dois métodos diferentes em dez amostras de solo, cujo teor em C variava de 0,2-0,3% a 3,4-4,2%. Um dos métodos foi o baseado na combustão por via seca, a 550-600°C, associado à volumetria de gases. O outro método fundamentou-se na oxidação do carbono, com solução de dicromato a quente (banho-maria), titulando-se o excesso de oxidante por iodometria. Foram executadas cinco determinações em cada amostra de terra, pelos dois métodos estudados. Os dados obtidos evidenciaram que a precisão dos dois métodos foi similar. Entretanto, o método por via úmida forneceu sempre uma porcentagem de carbono inferior à obtida pelo método baseado na combustão por via seca. Assim, nas dez amostras estudadas, o método por via úmida forneceu de 68,8 a 93,4% do carbono determinado por combustão, por via seca. Finalmente, deve ser salientado que o método de combustão por via seca, associado com volumetria de gases, é muito mais rápido do que o por via úmida e determina todas as formas de carbono orgânico do solo.

The SPONASTRIME dysplasia: familial short-limb dwarfism with saddle nose, spinal alterations and metaphyseal striation. Report of 4 siblings.

We report clinical, anthropometric and radiological findings in 4 siblings with a new type of skeletal dysplasia. 4 normally intelligent girls exhibit dwarfism between -3.4 and -4.6 standard deviations with accentuated shortening of the lower limbs, moderate deformity of the vertebral bodies, mildly striated metaphyses, saddle nose, frontal bossing, and relatively large head. The family pedigree suggests autosomal recessive inheritance. We propose the designation of SPONASTRIME dysplasia, derived from spondylar and nasal alterations with striation of the metaphyses.