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Content available remote Preparation and properties of organic/inorganic hybrid nanofibres
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EN
Considerable attention has been paid to hybrid organic–inorganic nanocomposites in recent years. Organic–inorganic hybrids have both the advantages of organic materials, such as a light weight, flexibility and good moldability, and inorganic materials, such as high strength, heat stability and chemical resistance. In this work, a polyvinyl acetate (PVAc)/titanium dioxide (TiO2) organic-inorganic hybrid was prepared by the sol–gel technique. Electrospinning was used to fabricate PVAc/TiO2 hybrid nanofibres. Scanning Electron Microscopy (SEM) was employed to study the morphology of the hybrid nanofibres. The mechanical and thermal properties were examined by an electronic tensile instrument and thermo gravimetric analyzer (TGA), respectively. The results indicated that the mechanical and thermal properties were improved with TiO2 included in the hybrids.
PL
W ostatnich latach znacznie wzrosło zainteresowanie hybrydowymi włóknami organicznonieorganicznymi. Włókna te maja korzystne właściwości włókien organicznych takie jak małą gęstość, giętkość i dobrą podatność na zmianę kształtu oraz nieorganicznych jak wysoką wytrzymałość, stabilność termiczną i odporność chemiczną. Praca przedstawia otrzymywanie hybrydowych włókien PVAc/TiO2 metodą zol-żel poprzez elektroprzędzenie. Morfologia włókien była badana metodą SEM. Właściwości mechaniczne sprawdzano stosując zrywarkę sterowaną elektronicznie, podczas gdy właściwości termiczne badano metoda TGA. Wyniki wykazały, że właściwości mechaniczne i termiczne zostały poprawione dzięki wprowadzeniu TiO2 do matrycy polimerowej.
EN
Mitochondrial uncoupling proteins play important roles in generation of metabolic thermogenesis, response to stress situations, and regulation of energy metabolism. We demonstrated here that the absence of LeUCP in tomato inhibited photosynthesis using virusinduced gene-silencing approach. A significant decrease in the rate of CO2 assimilation in LeUCP-silencing plants was observed over a range of different light intensities. Absence of LeUCP resulted in lower net photosynthetic rate, lightsaturated rate of the CO2 assimilation (Asat), maximum carboxylation rates (Vcmax) and maximum RuBP regeneration rate (Jmax). Activities of ribulose-1,5-bisphosphate carboxylase/oxygenase Rubisco and stromal fructose-1,6- bisphosphatase and genes expression levels encoded Calvin cycle enzymes of LeUCP gene-silencing plants were inhibited. However, silencing of LeUCP gene had no effect on Fv/Fm, but decreased photochemical quenching and electron transport rate. Meanwhile, non-photochemical quenching and Je (PSII), the distribution of Je (PCR) and Je (PCO), the content of AsA, NAD, and the ratios of NAD?/ NADH, AsA/DHA were significantly reduced with increased reactive oxygen species while GSH and GSSG were unaltered. Taken together, these results strongly suggest that LeUCP gene in tomato leaves is crucial in maintaining the redox poise of the mitochondrial electron transport chain to facilitate photosynthetic metabolism.
EN
Microzooplankton plays an important role in controlling the standing crop of phytoplankton and primary production. However, research on microzooplankton grazing has mainly focused on the ocean and only rarely on eutrophic lakes. In this study we investigated plankton community structures, microzooplankton grazing rates (m), and phytoplankton growth rates (μ) in order to explore microzooplankton grazing in 2 eutrophic sub-lakes of West Lake, Hangzhou, China (Waihu and Xilihu). Results showed that Pseudanabaena sp. was dominant in Waihu without submerged macrophytes, and the larger phytoplankton (>2 μm) biomass was higher than the picophytoplankton (<2 μm) biomass. However, Xilihu with macrophytes growing was mainly composed of diatoms and green algae, and there was no significant difference between larger phytoplankton and picophytoplankton biomass. Furthermore, in West Lake, the values of m (ranging from 1.58~3.33/d) and μ (ranged from 1.38~3.05/d) were higher than those in the ocean. The higher m, μ, and relative preference index (RPI) for picophytoplankton in Waihu indicated that microzooplankton had a significant size-selective grazing on picophytoplankton. However, no significant size-selection was found in Xilihu. These different responses of plankton in Waihu and Xilihu might explain why larger phytoplankton occupy a dominant position in eutrophic lakes.
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