Digestibilidade "in vivo" dos constituintes da parede celular do capim quicuio-da-amazônia (Brachiaria humidicola (Rendle) Schweickerdt).

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Theoretical study of molecular electronic excitations and optical transitions of C60

We report results on ab initio calculations of excited states of the fullerene molecule by using configuration interaction (CI) approach with singly excited determinants (SCI). We have used both the experimental geometry and the one optimized by the density functional method and worked with basis sets at the cc-pVTZ and aug-cc-pVTZ level. Contrary to the early SCI semiempirical calculations, we find that two lowest $^1 T_{1u} \leftarrow {}^1 A_g$ electron optical lines are situated at relatively high energies of ~5.8 eV (214 nm) and ~6.3 eV (197 nm). These two lines originate from two $^1 T_{1u} \leftarrow {}^1 A_g$ transitions: from HOMO to (LUMO+1) ($6h_u \to 3t_{1g}$) and from (HOMO--1) to LUMO ($10h_g \to 7t_{1u}$). The lowest molecular excitation, which is the $1 ^3 T_{2g}$ level, is found at ~2.5 eV. Inclusion of doubly excited determinants (SDCI) leads only to minor corrections to this picture. We discuss possible assignment of absorption bands at energies smaller than 5.8 eV (or $\lambda$ larger than 214 nm).Comment: 6 pages, 1 figure, 9 Table

Chronic intravenous aminobisphosphonate therapy increases high-density lipoprotein cholesterol and decreases low-density lipoprotein cholesterol

Nowadays, bisphosphonates are considered the drugs of choice for the treatment of several bone disorders. Their exact mechanism of action is not clear but recently it has been reported that the aminobisphosphonates inhibit cholesterol biosynthesis and that this might be relevant for their actions on bone osteoclasts. The study includes 87 postmenopausal women with moderate to severe osteoporosis. The patients were randomly assigned to intravenous (iv) infusion of 50 mg of the aminobisphosphonate Neridronate dissolved in 100 ml of saline solution every 2 months for a year (44 patients). The remaining 43 served as controls. At the time of each infusion blood samples were obtained for the evaluation of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), and total and bone alkaline phosphatase (AP). Free deoxypyridinoline (f-DPD) was measured in fasting urine specimens. In the control group no significant changes were observed throughout the study period for any of the biochemical variables. In the Neridronate-treated patients both bone AP and f-DPD excretion fell significantly by 15-20%. In these patients serum total cholesterol and serum triglycerides showed marginal decreases, which were occasionally significant. LDL-C and Apo B fell by 5-6% and these changes were statistically significant at most time points. Apo A-I and HDL-C rose progressively with time. At the 12th month, HDL-C rose 17-18% (p < 0.0001) above the baseline values. Similar findings were obtained in four postmenopausal women given high iv doses of Pamidronate or Alendronate. In conclusion aminobisphophonates, at least when given iv, induce remarkable and unexpected effects on lipid metabolism with a final profile that might be clinically relevant

Factors controlling spatio-temporal variation in carbon dioxide efflux from surface litter, roots, and soil organic matter at four rain forest sites in the eastern Amazon

[1] This study explored biotic and abiotic causes for spatio-temporal variation in soil respiration from surface litter, roots, and soil organic matter over one year at four rain forest sites with different vegetation structures and soil types in the eastern Amazon, Brazil. Estimated mean annual soil respiration varied between 13-17 t C ha(-1) yr(-1), which was partitioned into 0-2 t C ha(-1) yr(-1) from litter, 6-9 t C ha(-1) yr(-1) from roots, and 5-6 t C ha(-1) yr(-1) from soil organic matter. Litter contribution showed no clear seasonal change, though experimental precipitation exclusion over a one-hectare area was associated with a ten-fold reduction in litter respiration relative to unmodified sites. The estimated mean contribution of soil organic matter respiration fell from 49% during the wet season to 32% in the dry season, while root respiration contribution increased from 42% in the wet season to 61% during the dry season. Spatial variation in respiration from soil, litter, roots, and soil organic matter was not explained by volumetric soil moisture or temperature. Instead, spatial heterogeneity in litter and root mass accounted for 44% of observed spatial variation in soil respiration (p < 0.001). In particular, variation in litter respiration per unit mass and root mass accounted for much of the observed variation in respiration from litter and roots, respectively, and hence total soil respiration. This information about patterns of, and underlying controls on, respiration from different soil components should assist attempts to accurately model soil carbon dioxide fluxes over space and time

Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis

Crescimento da cana-de-açúcar (1ª soca) sob diferentes níveis de fertirrigação potássica.

O estudo teve como objetivo avaliar o crescimento de cana-de-açúcar, ciclo de 1ª soca, variedade RB867515, sob diferentes níveis de fertirrigação potássica. O ensaio foi conduzido em uma área experimental na Usina COMVAP ? Açúcar e Álcool Ltda., município de União, PI