Biomimetic synthesis of xuxuarines E alpha and E beta: Structure revision of Rzedowskia bistriterpenoids

Reaction of pristimerin with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in a biomimetic-type coupling leading to xuxuarines E alpha and E beta and not the previously reported Rzedowskia bistriterpenoids I and II suggesting that the structures proposed for these natural products need revision. A product obtained in this reaction by an unusual Diels-Alder addition followed by retro-Diels-Alder-type elimination was characterized as pristimerin dicyanophenalenedione. Complete H-1, and C-13 NMR spectral assignments of xuxuarines Ea and Eb have been made by the application of 1D and 2D NMR techniques. (c) 2007 Elsevier Ltd. All rights reserved.

Absolute configuration reassignment of two chromanes from Peperomia obtusifolia (Piperaceae) using VCD and DFT calculations

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

Itaipu reservoir limnology: eutrophication degree and the horizontal distribution of its limnological variables

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

Análise do equilíbrio em pacientes hemiparéticos após o treino com o programa Wii Fit

OBJETIVO: A hemiparesia é um comprometimento parcial do hemicorpo que altera o equilíbrio, sendo este essencial para as atividades funcionais. OBJETIVO: Avaliar o equilíbrio em pacientes hemiparéticos submetidos ao treino de equilíbrio com o programa Wii Fit, que atuou como um recurso de biofeedback visual. MÉTODO: Foram selecionados 12 pacientes hemiparéticos pós AVE, 5 do sexo masculino e 7 do sexo feminino, com idade média de 58 ± 12,57 anos, divididos aleatoriamente em dois grupos. Um deles realizou a fisioterapia convencional (GC) pelo período de uma hora, o outro realizou por trinta minutos e mais trinta minutos de treino de equilíbrio com auxílio do Wii Fit (GW), duas vezes por semana durante cinco semanas, completando dez sessões. O equilíbrio foi avaliado antes e após as intervenções, por meio da aplicação da Escala de Equilíbrio de Berg (EEB) e pela estabilometria, que mensura a oscilação do centro de pressão (COP), nos eixos ântero-posterior (AP) e médio-lateral (ML), por uma plataforma de pressão em duas condições: de olhos abertos (OA) e olhos fechados (OF). RESULTADOS: de acordo com a EEB, os pacientes, tanto do GC quanto o do GW, obtiveram maior controle do equilíbrio estático e dinâmico. Na avaliação do COP no eixo ML, os indivíduos do GC e do GW tiveram diminuição na oscilação ML após a intervenção proposta para cada grupo, nas condições de OA e OF. No eixo AP do COP, o GC não teve diminuição na oscilação AP de OA e OF, e o GW apresentou diminuição na oscilação AP de OA e OF. CONLUSÃO: O presente estudo demonstra que a fisioterapia associada ao treino de equilíbrio com o Wii Fit apresenta resultados significantes na reabilitação dos indivíduos hemiparéticos, obtendo, assim, mais um recurso terapêutico na fisioterapia.

Adubação foliar com silício na cultura do milho

Inúmeros trabalhos têm demonstrado o efeito benéfico da adubação com silício sobre o acréscimo da produção de diversas culturas, como, por exemplo, arroz, cana-de-açúcar e batata. No entanto, são escassas as informações sobre os benefícios nutricionais do silício para a cultura do milho. Desta maneira, objetivou-se, neste estudo, avaliar o efeito de doses e épocas de aplicação de silício, via foliar, nas características agronômicas e na produtividade do milho, cultivado no ano agrícola 2007/2008. O delineamento experimental adotado foi o de blocos casualizados, em esquema fatorial (4 x 3) + 1, com quatro repetições, envolvendo doses de silício (130, 260, 390 e 520 g ha-1 de Si) aplicadas via foliar, épocas de aplicação (2, 5 e 8 folhas expandidas) e uma testemunha (sem aplicação de Si). As variáveis analisadas foram altura das plantas e a inserção da primeira espiga, diâmetro de colmo, índice de clorofila foliar, teor foliar de silício, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O silício aplicado via foliar influenciou somente o teor foliar de Si.

Reguladores vegetais e qualidade tecnológica da cana-de-açúcar em meio de safra

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

Liming in the transition to no-till under a wheat-soybean rotation

Soil and subsoil aluminium toxicity has been one of the main limiting factors for soybean and wheat yields in tropical soils. Usually liming is the most effective way to deal with soil acidity and Al toxicity, but in no-till systems the soil is not disturbed making it impossible to incorporate lime in the arable layer, and lime has been usually applied on the soil surface. In this paper soybean and wheat responses to lime applied on the soil surface and/or incorporated in the soil arable layer were evaluated during the transition from conventional tillage to a no-till system. The experiment was conducted for 3 years in Parana, Brazil, using a wheat-soybean rotation. Lime rates ranging from 0.0 to 9.0 t ha(-1) were incorporated down to 20 cm and 4.5 t ha(-1) were spread or not on the soil surface. Soil samples were taken down to 60 cm, 39 months after the first lime application. Soil chemical characteristics were affected by lime application down to 60 cm deep in the profile. Soybean responded to lime irrespective of application method, but the highest accumulated yield was obtained when lime was incorporated into the arable layer. For wheat, the more sensitive the cultivar, the greater was the response to lime. During the introduction of a no-till system, lime must be incorporated into the arable layer when the wheat cultivar is Al-sensitive. (C) 2007 Elsevier B.V. All rights reserved.

Microbial populations and activities in sewage sludge and phosphate fertilizer-amended soil

A greenhouse study was conducted to determine the number of microbial populations and activities in sewage sludge and phosphate fertilizer-amended dark red latosoil for cultivation of tomato plants. Sewage sludge was applied at doses of 0, 10, 20, 40, 80 and 160 t ha(-1), and phosphate (P2O5) at doses of 0, 100, 200, 400 and 800 kg ha(-1). The bacterial populations increased as a function of sewage sludge and phosphate application. Fungal populations were not affected by the application of phosphate alone but were increased by the application of sewage sludge. Phosphate doses higher than 100-200 kg ha(-1) in combination with sewage sludge inhibited both bacterial and fungal growth. The responses determined by microbial counts were reflected in the microbial biomass values, with a more significant effect of sewage sludge than of phosphate or of a combination of both. These results confirm the need for a carbon and energy source (represented here by sewage sludge) for microbial growth in a soil poor in organic matter. Dehydrogenase and urease activities reflected the results of the microbial populations due to the effect of sewage sludge and phosphate, but no satisfactory result was obtained for phosphatase. Urease activity was expressed by a linear regression equation as the result of the effect of sewage sludge, and by a quadratic regression equation as the result of the effect of phosphate. All parameters investigated showed a significant correlation with bacterial counts but not with fungal counts, indicating a greater effect of sewage sludge and phosphate on bacteria than on fungi.

Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS) of a resin modified glass ionomer cement (RM-GIC) to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12). In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE) prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37 degrees C for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5%) and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

Repair bond strength of a resin composite to alumina-reinforced feldspathic ceramic

This study compared the microtensile bond strength of a repair resin to an alumina-reinforced feldspathic ceramic (Vitadur-alpha, Vita) after 3 surface conditioning methods: Group 1, etching with 9.6% hydrofluoric acid for 1 minute plus rinsing and drying, followed by application of silane for 5 minutes; group 2, airborne particle abrasion with 110-mm aluminum oxide using a chairside air-abrasion device followed by silane application for 5 minutes; group 3, chairside tribochemical silica coating with 30-mu m SiOx followed by silane application for 5 minutes (N = 30). Group 1 presented the highest mean bond strength (19.7 +/- 3.8 MPa), which was significantly higher than those of groups 2 (10 +/- 2.6 MPa) and 3 (10.4 +/- 4 MPa) (P <.01). Scanning electron microscope analysis of the failure modes demonstrated predominantly mixed types of failures, with adhesive and/or cohesive failures in all experimental groups.

Structure determination of an organometallic 1-(diazenylaryl)ethanol: A novel toxin subclass from the web of the spider Nephila clavipes

A novel chemical subclass of toxin, [1-(3-diazenylphenyl) ethanol]iron, was identified among the compounds present in the web of the spider Nephila clavipes. This type of compound is not common among natural products, mainly in spider-venom toxins; it was shown to be a potent paralytic and/or lethal toxin applied by the spider over its web to ensure prey capture only by topical application. The structure was elucidated by means of ESI mass spectrometry, H-1-NMR spectroscopy, high-resolution (HR) mass spectrometry, and ICP spectrometry. The structure of [1-( 3-diazenylphenyl)ethanol] iron and the study of its insecticidal action may be used as a starting point for the development of new drugs for pest control in agriculture.

Analytical attitude propagation with non-singular variables and gravity gradient torque for spin stabilized satellite

An analytical approach for the spin stabilized satellite attitude propagation is presented using the non-singular canonical variables to describe the rotational motion. Two sets of variables were introduced for Fukushima in 1994 by a canonical transformation and they are useful when the angle between z-satellite axis of a coordinate system fixed in artificial satellite and the rotational angular momentum vector is zero or when the angle between Z-equatorial axis and rotation angular momentum vector is zero. Analytical solutions for rotational motion equations and torque-free motion are discussed in terms of the elliptic functions and by the application of some simplification to get an approximated solution. These solutions are compared with a numerical solution and the results show a good agreement for many rotation periods. When the mean Hamiltonian associated with the gravity gradient torque is included, an analytical solution is obtained by the application of the successive approximations' method for the satellite in an elliptical orbit. These solutions show that the magnitude of the rotation angular moment is not affected by the gravity gradient torque but this torque causes linear and periodic variations in the angular variables, long and short periodic variations in Z-equatorial component of the rotation angular moment and short periodic variations in x-satellite component of the rotation angular moment. The goal of this analysis is to emphasize the geometrical and physical meaning of the non-singular variables and to validate the approximated analytical solution for the rotational motion without elliptic functions for a non-symmetrical satellite. The analysis can be applied for spin stabilized satellite and in this case the general solution and the approximated solution are coincidence. Then the results can be used in analysis of the space mission of the Brazilian Satellites. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

MICROFIBRILS - NEGLECTED COMPONENTS OF PRESSURE-BEARING TENDONS

Some tendons wrap around joints and receive compressive forces besides transferring the tension forces from muscle to bone. These tendons develop a fibrocartilaginous structure which enables them to withstand pressure. This article describes the existence and distribution of microfibrils (or preelastic fibers) in the pressure-bearing tendons of rabbits and dogs by the application of histochemical assays and transmission electron microscopy. Rabbit and dog tendons possess no mature elastic fibers. The rabbit tendon exhibits some response to Weigert's method prior to oxidation which indicates the existence of the so-called elaunin fibers, especially in the pressure zone. Oxidation with peracetic acid or oxone discloses intricate aspects of the oxytalan fiber distribution in both tension and pressure zones of the dog and rabbit tendons. Bundles of 12 nm microfibrils were demonstrated in the rabbit tendon by electron microscopy after fixation in the presence of tannic acid. The existence of preelastic fibers in the pressure-bearing tendons has been neglected and they are assumed to have importance in the microarchitecture of the tissue and in the ability of the tendon to support tension and compression forces.

RELATIVE GROWTH OF THE SPECKLED SWIMMING CRAB ARENAEUS-CRIBRARIUS (LAMARCK, 1818) (BRACHYURA, PORTUNIDAE), NEAR UBATUBA, STATE OF SAO-PAULO, BRAZIL

Arenaeus cribrarius is a mainly tropical crab that occurs in the Western Atlantic Ocean, Brazil being its type-locality. The species ranges from Vinevard Sound, Massachusetts, USA to La Paloma, Uruguay. Information about this species is scarce. The relative growth of A. cribrarius was analyzed, based on some morphometric relations, where the carapace width, excluding lateral spines (CW), was used as an independent variable. A total of 403 specimens (189 males and 214 females), was collected in Ubatuba, State of São Paulo, Brazil, with otter-trawls. The animals were sexed and sorted to maturation phase (juvenile or adult). Some measurements were made: carapace (length and width excluding lateral spines), abdomen (greatest width of the fifth somite in females and the sixth in males) and major chela (greatest length, width and height, dactylus length). This study was made by the application of the power function (y=a.x(b)) which was fitted to the data and the pattern of growth established for each parameter by the ''b''-value (constant of allometry), as positive allometry (b>1), negative allometry (b<1) or isometry (b=1). The morphometric relations of the carapace showed a tendency to isometry. In females, the abdominal width grew in positive allometry, higher in juveniles (b=1.33) than in adults (b=1.18). In this case, an overlap and discontinuity was noticed between the phases over a carapace width range of 55 to 70 mm, where the puberty molt occurs. The majority of relationships showed that the major chela of the males grew in positive allometry, however, the greatest allometric difference between the phases was observed towards the propodus length with 1.09 as juvenile and 1.26 as adult ''b''values. In the males, this variable showed an inflection between the CW range of 45' to 55 mm, where the transition to the maturation phase occurs. The relative growth of this species is similar to those of previously studied species. This indicates, that the propodus length and the abdominal width are the morphometric variables most appropriate to estimate the size of the beginning of the sexual maturity for males and females of this species, respectively.

Crescimento radicular e aéreo de cultivares de arroz de terras altas em função da calagem

This work aimed to evaluate root growth, shoot development and nutrient absorption efficiency by rice cultivars Caiapo and Maravilha as affected by lime application. The experiment was carried out in a greenhouse, with treatments set up by Caiapo and Maravilha cultivars in combination with the base saturation (V%) of 10%, 40% and 70%. The experiment was in a randomized complete block design, with four replications. The number of tillers, root length, root dry matter, leaves and stems, leaf content and macronutrients absorption efficiency were evaluated. Comparing cultivars, Maravilha cultivar presented higher root dry weight, root length, number of stems, dry matter of stems and shoot than Caiapo cultivar, as well as accumulated more nutrients in the shoots. on the other hand, nutrient contents were higher in the cultivar Caiapo compared to Maravilha. Maravilha cultivar shows greater root and shoot growth while Caiapo shows higher nutrient absorption efficiency from the soil. The base saturation of 40% is the most effective for both cultivars.