The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Francisco Leon - One of the best experts on this subject based on the ideXlab platform.
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phenolic compounds antioxidant activity and ultrastructural study from protea hybrid susara
Industrial Crops and Products, 2014Co-Authors: Francisco Leon, Carmen Alfayate, Candelaria Vera Batista, A Lopez, Milagros Rico, Ignacio BrouardAbstract:Abstract In the present study we investigated the chemical composition and the phenolic contents of the ethanolic extract from aerial parts of Protea hybrid ‘Susara’, its antioxidant activity and also the structure and ultrastructure of the leaves and stems by light microscopy (LM) and transmission electron microscopy (TEM). Phytochemical research led to the isolation of twelve compounds including: (6-ethoxy-3,5-dihydroxy-4-oxotetrahydro-2H-pyran-2-yl)methyl 4-hydroxybenzoate ( 1 ), 4-ethoxy-2,3-dihydroxy-4-oxobutyl 4-hydroxybenzoate ( 3 ), 2-ethoxy-4-(hydroxymethyl)phenol ( 4 ) and 1,5-anhydro- d -glucitol ( 5 ). Moreover, fourteen phenolic compounds were identified and quantified by RP-HPLC, and the predominant was catechin, followed by gallic and syringic acids. Compound 4 showed the highest radical scavenging activity (98%) with a half-time ( t 1/2 ) of 10 s. In TEM, the phenolic compounds were osmiophilic, appearing within the Cell Lumen of different tissues as isolated droplets of different sizes and fine granular material. Aerial parts presented thick cuticles and heavily lignified tissues with strong reinforcements of sclerenchyma, all indicating scleromorphic features. Our finding suggested that some agriculture waste biomass could be converted into high-added value products with a potential use within the food preservation, pharmaceutical, cosmetic and therapeutic industries.
Ignacio Brouard - One of the best experts on this subject based on the ideXlab platform.
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phenolic compounds antioxidant activity and ultrastructural study from protea hybrid susara
Industrial Crops and Products, 2014Co-Authors: Francisco Leon, Carmen Alfayate, Candelaria Vera Batista, A Lopez, Milagros Rico, Ignacio BrouardAbstract:Abstract In the present study we investigated the chemical composition and the phenolic contents of the ethanolic extract from aerial parts of Protea hybrid ‘Susara’, its antioxidant activity and also the structure and ultrastructure of the leaves and stems by light microscopy (LM) and transmission electron microscopy (TEM). Phytochemical research led to the isolation of twelve compounds including: (6-ethoxy-3,5-dihydroxy-4-oxotetrahydro-2H-pyran-2-yl)methyl 4-hydroxybenzoate ( 1 ), 4-ethoxy-2,3-dihydroxy-4-oxobutyl 4-hydroxybenzoate ( 3 ), 2-ethoxy-4-(hydroxymethyl)phenol ( 4 ) and 1,5-anhydro- d -glucitol ( 5 ). Moreover, fourteen phenolic compounds were identified and quantified by RP-HPLC, and the predominant was catechin, followed by gallic and syringic acids. Compound 4 showed the highest radical scavenging activity (98%) with a half-time ( t 1/2 ) of 10 s. In TEM, the phenolic compounds were osmiophilic, appearing within the Cell Lumen of different tissues as isolated droplets of different sizes and fine granular material. Aerial parts presented thick cuticles and heavily lignified tissues with strong reinforcements of sclerenchyma, all indicating scleromorphic features. Our finding suggested that some agriculture waste biomass could be converted into high-added value products with a potential use within the food preservation, pharmaceutical, cosmetic and therapeutic industries.
E A Vaganov - One of the best experts on this subject based on the ideXlab platform.
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temperature induced responses of xylem structure of larix sibirica pinaceae from the russian altay
American Journal of Botany, 2013Co-Authors: Patrick Fonti, Marina V Bryukhanova, Vladimir S Myglan, Alexander V Kirdyanov, Oksana V Naumova, E A VaganovAbstract: Premise of the study: Xylem structure determines the hydraulic and mechanical properties of a stem, and its plasticity is fundamental for maintaining tree performance under changing conditions. Unveiling the mechanism and the range of xylem adjustment is thus necessary to anticipate climate change impacts on vegetation. Methods: To understand the mechanistic process and the functional impact of xylem responses to warming in a cold-limited environment, we investigated the relationship between temperature and tracheid anatomy along a 312-yr tree-ring chronology of Larix sibirica trees from the Altay Mountains in Russia. Key results: Climate-growth analyses indicated that warming favors wider earlywood Cell Lumen, thicker latewood walls, denser maximum latewood, and wider rings. The temperature signal of the latewood was stronger ( r > 0.7) and covered a longer and more stable period (from June to August) than that of earlywood and tree-ring width. Long-term analyses indicated a diverging trend between Lumen and Cell wall of early- and latewood. Conclusions: Xylem anatomy appears to respond to warming temperatures. A warmer early-growing season raises water conduction capacity by increasing the number and size of earlywood tracheids. The higher-performing earlywood tracheids promote more carbon fi xation of the latewood Cells by incrementing the rate of assimilation when summer conditions are favorable for growth. The diverging long-term variation of Lumen and Cell wall in earlywood vs. latewood suggests that xylem adjustments in latewood increase mechanical integrity and support increasing tree size under the ameliorated growing conditions.
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intra annual variability of anatomical structure and δ13c values within tree rings of spruce and pine in alpine temperate and boreal europe
Oecologia, 2009Co-Authors: E A Vaganov, Ernst Detlef Schulze, Marina V Skomarkova, Alexander Knohl, Willi A Brand, Christiane RoscherAbstract:Tree-ring width, wood density, anatomical structure and 13C/12C ratios expressed as δ13C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, δ13C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, Cell-wall thickness, Cell-wall area and Cell-Lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained <20% of the variation in tree-ring width and wood density over consecutive years, while 29–58% of the variation in tree-ring width were explained by autocorrelation between tree rings. An intensive study of tree rings between 1999 and 2003 revealed that tree ring width and δ13C-values of whole wood were significantly correlated with length of the growing season, net radiation and vapor pressure deficit. The δ13C-values were not correlated with precipitation or temperature. A highly significant correlation was also found between δ13C of the early wood of one year and the late wood of the previous year, indicating a carry-over effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the δ13C between late wood and early wood. The results are interpreted in the context of the biochemistry of wood formation and its linkage to storage products. It is clear that the relations between δ13C and tree-ring width and climate are multi-factorial in seasonal climates.
Xiaoying Dong - One of the best experts on this subject based on the ideXlab platform.
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improvement of decay resistance of wood via combination treatment on wood Cell wall swell bonding with maleic anhydride and graft copolymerization with glycidyl methacrylate and methyl methacrylate
International Biodeterioration & Biodegradation, 2011Co-Authors: Xiaoying Dong, Yixing Liu, Fenghu WangAbstract:Abstract Poplar wood ( Populus ussuriensis Kom) was modified by a novel combined two-step treatment to improve its decay resistance. Maleic Anhydride (MAN) was first employed to swell and bond to wood Cell wall, and then mixed monomers of glycidyl methacrylate/methyl methacrylate (GMA/MMA) were used to graft copolymerization within wood Cell Lumen. The swelling and bonding of Cell wall by MAN, interfacial compatibility between resultant polymer from GMA/MMA monomers and wood Cell wall, and decay resistance of all composites were tested and analyzed by Scanning electron microscopy–Energy dispersive X-ray (SEM–EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) apparatus. The results indicate that the volume of poplar wood treated by MAN swells about 9% with about 15% of weight percent gain, and MAN chemically bonds to the Cell wall through substitution reaction with hydroxyl group, and the grafting adduct mainly remains as an amorphous form. The resultant Poplar-MAN shows improved decay resistance of 69.79% against brown fungus ( Gloeophyllum trabeum (Pers. ex Fr.) Murr.) and 81.42% against white fungus ( Phanerochaete chrysosporium Burdsall.) over those of untreated Poplar, respectively. After the combined two-step treatment, GMA and MMA are copolymerized within wood Cell Lumen, and the resultant polymer is also grafted onto wood Cell wall, resulting in the improvement of interfacial compatibility between polymer and wood substance without obvious gaps. The decay resistance of the resultant composite from the combined two-step treatment against the brown decay fungus and the white decay fungus is improved by 97.64% and 99.17%, respectively, compared with those of untreated poplar wood; and also more exCellent than those of MMA treated wood, GMA/MMA monomers treated wood, organic 3-Iodo-2-Propynyl Butyl Carbamate (IPBC) treated wood and inorganic boron compounds treated wood, respectively.
Sandberg Dick - One of the best experts on this subject based on the ideXlab platform.
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Surface hardness and flammability of Na2SiO3 and nano-TiO2 reinforced wood composites
2019Co-Authors: Garškaitė Edita, Karlsson Olov, Stankevičiūtė Živilė, Kareiva Aivaras, Jones Dennis, Sandberg DickAbstract:The objective of this study was to explore an effect of the combined inorganic materials on the wood hardness and flame-retardancy properties in a concept of sustainable material management. Herein, the reinforcement of Scots pine (Pinus sylvestris L.) sapwood with sodium silicate and TiO2 nanoparticles via vacuum-pressure technique is reported. Pyrolysis of modified wood was studied by TG-FTIR analysis; the results showed that maximum weight loss for the modified wood was obtained at 40–50 °C lower temperatures compared to the reference untreated wood. The Gram–Schmidt profiles and spectra extracted at maxima absorption from Gram–Schmidt plots indicated chemical changes in wood–inorganic composites. SEM/EDS analysis revealed the presence of Na–O–Si solid gel within the wood-Cell Lumen and showed that TiO2 was homogeneously distributed within the amorphous Na–O–Si glass-forming phase to form a thin surface coating. EDS mapping further revealed the higher diffusivity of sodium into the Cell wall compared to the silicon compound. The presence of amorphous sodium silicate and nano-TiO2 was additionally confirmed by XRD analysis. FTIR spectra confirmed the chemical changes in Scots pine sapwood induced by alkalization. Brinell hardness test showed that the hardness of the modified wood increased with the highest value (44% increase in hardness) obtained for 10% Na2SiO3–nTiO2 modified wood. The results showed good correlation between TG and flammability test; limiting oxygen index (LOI) values for the wood–inorganic composites increased by 9–14% compared to the untreated wood
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Surface hardness and flammability of Na2SiO3 and nano-TiO2 reinforced wood composites
'Royal Society of Chemistry (RSC)', 2019Co-Authors: Garškaitė Edita, Karlsson Olov, Jones Dennis, Stankeviciute Zivile, Aivaras Kareiva, Sandberg DickAbstract:The objective of this study was to explore an effect of the combined inorganic materials on the wood hardness and flame-retardancy properties in a concept of sustainable material management. Herein, the reinforcement of Scots pine (Pinus sylvestris L.) sapwood with sodium silicate and TiO2 nanoparticles via vacuum-pressure technique is reported. Pyrolysis of modified wood was studied by TG-FTIR analysis; the results showed that maximum weight loss for the modified wood was obtained at 40–50 °C lower temperatures compared to the reference untreated wood. The Gram–Schmidt profiles and spectra extracted at maxima absorption from Gram–Schmidt plots indicated chemical changes in wood–inorganic composites. SEM/EDS analysis revealed the presence of Na–O–Si solid gel within the wood-Cell Lumen and showed that TiO2 was homogeneously distributed within the amorphous Na–O–Si glass-forming phase to form a thin surface coating. EDS mapping further revealed the higher diffusivity of sodium into the Cell wall compared to the silicon compound. The presence of amorphous sodium silicate and nano-TiO2 was additionally confirmed by XRD analysis. FTIR spectra confirmed the chemical changes in Scots pine sapwood induced by alkalization. Brinell hardness test showed that the hardness of the modified wood increased with the highest value (44% increase in hardness) obtained for 10% Na2SiO3–nTiO2 modified wood. The results showed good correlation between TG and flammability test; limiting oxygen index (LOI) values for the wood–inorganic composites increased by 9–14% compared to the untreated wood.Validerad;2019;Nivå 2;2019-09-18 (johcin)