900 resultados para inter-granule bonds
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The influence of climatic variations on the herbaceous component of the "caatinga" vegetation was examined in the state of Pernambuco, Brazil. A total of 105 1 × 1 m-plots were established, of which 35 were in a level micro-habitat, 35 in a riparian micro-habitat, and 35 in a stony microhabitat. During two consecutive years all herbaceous plants in these plots were counted, measured (height and diameter), and collected for identification. The Shannon-Wiener diversity index and the equitability were calculated for each year, as well as the density, frequency, dominance, total basal area and importance index for each species. The total annual pluviometric was 819.5 and 448.8 mm in 2002 and 2003, respectively. The herbaceous flora in the study area was composed of 71 species, of which 58 were sampled in the plots. The families with the greatest species richness were Malvaceae (8 species), Euphorbiaceae (7), Poaceae (6), Convolvulaceae (4), Fabaceae (4), and Portulacaceae (4). The diversity indices were 2.66 and 3.01 nats ind-1 in 2002 and 2003, respectively. The density, frequency, dominance and importance value of herbaceous populations, as well as, the height and diameter of plants were low in the dryer year. The riparian group was the most isolated of the microhabitats examined, both in terms of its floristic and its population structure. Annual seasonal climatic variations greatly modified these populations structure during the course of this study, emphasizing the fact that long-term studies are needed in order to better understand the dynamics of the herbaceous component of the "caatinga" vegetation.
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A glutamate-sensitive inward current (Iglu) is described in rat cerebellar granule neurons and related to a glutamate transport mechanism. We examined the features of Iglu using the patch-clamp technique. In steady-state conditions the Iglu measured 8.14 ± 1.9 pA. Iglu was identified as a voltage-dependent inward current showing a strong rectification at positive potentials. L-Glutamate activated the inward current in a dose-dependent manner, with a half-maximal effect at about 18 µM and a maximum increase of 51.2 ± 4.4%. The inward current was blocked by the presence of dihydrokainate (0.5 mM), shown by others to readily block the GLT1 isoform. We thus speculate that Iglu could be attributed to the presence of a native glutamate transporter in cerebellar granule neurons.
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The use of recovered paper as raw material in the paper and board industry has increased heavily during recent decades. At the same time, growing environmental awareness has raised the interest in recycling and a more sustainable way of living, at least in high-income countries. This paper combines these topics and explores how economic, demographic and environmental factors have affected the recovery and utilization of recycled paper between 1992 and 2010 in a sample of 70 countries. This study updates and extends the previous research on the topic using panel data and panel data estimation methods. The results confirm the roles of economic determinants but also indicate that concern for the environment impacts the recovery of recycled paper particularly in high-income countries. Moreover, the motives for recycling appear to depend on the income level of a country, which is something that future policies should consider.
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[N. 1:1400000].
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Since cellulose is a linear macromolecule it can be used as a material for regenerated cellulose fiber products e.g. in textile fibers or film manufacturing. Cellulose is not thermoformable, thus the manufacturing of these regenerated fibers is mainly possible through dissolution processes preceding the regeneration process. However, the dissolution of cellulose in common solvents is hindered due to inter- and intra-molecular hydrogen bonds in the cellulose chains, and relatively high crystallinity. Interestingly at subzero temperatures relatively dilute sodium hydroxide solutions can be used to dissolve cellulose to a certain extent. The objective of this work was to investigate the possible factors that govern the solubility of cellulose in aqueous NaOH and the solution stability. Cellulose-NaOH solutions have the tendency to form a gel over time and at elevated temperature, which creates challenges for further processing. The main target of this work was to achieve high solubility of cellulose in aqueous NaOH without excessively compromising the solution stability. In the literature survey an overview of the cellulose dissolution is given and possible factors contributing to the solubility and solution properties of cellulose in aqueous NaOH are reviewed. Furthermore, the concept of solution rheology is discussed. In the experimental part the focus was on the characterization of the used materials and properties of the prepared solutions mainly concentrating on cellulose solubility and solution stability.
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Variantti A.
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Arkit: 1 arkintunnukseton lehti, A-B4 C2. - S. [2] tyhjä.
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Arkit: 1 arkintunnukseton lehti, C3-C4 D-E4. - S. [2] ja [40] tyhjä.
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Invokaatio: Σ.Θ.
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Dedikaatio: Carl Rehbinder.
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Dedikaatio: Carolus Fridericus Mennander, Nicolaus Hedeen, Johannes Gottleben, Henric Soenck, Pehr Sonck, Abraham Sonck, Johan Rahgo, Margareta Hoeckert född Turowia.
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Invokaatio: D.D.
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Variantti B.