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Sample records for birch wood xylan

  1. Properties of plasticized composite films prepared from nanofibrillated cellulose and birch wood xylan

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Blomfeldt, Thomas O. J.; Hedenqvist, Mikael S.

    2012-01-01

    Xylans, an important sub-class of hemicelluloses, represent a largely untapped resource for new renewable materials derived from biomass. As with other carbohydrates, nanocellulose reinforcement of xylans is interesting as a route to new bio-materials. With this in mind, birch wood xylan was comb......Xylans, an important sub-class of hemicelluloses, represent a largely untapped resource for new renewable materials derived from biomass. As with other carbohydrates, nanocellulose reinforcement of xylans is interesting as a route to new bio-materials. With this in mind, birch wood xylan...... was combined with nanofibrillated cellulose (NFC) and films were cast with and without glycerol, sorbitol or methoxypolyethylene glycol (MPEG) as plasticizers. Microscopy revealed some NFC agglomeration in the composite films as well as a layered nanocellulose structure. Equilibrium moisture content...

  2. Synthesis and characterization of birch wood xylan succinoylated in 1-n-butyl-3-methylimidazolium chloride

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Plackett, David

    2011-01-01

    The chemical modification of birch wood xylan was undertaken in the ionic liquid 1-n-butyl-3-methylimidazolium chloride (C4mimCl) using three different long-chain succinic anhydrides: n-octenyl succinic anhydride (n-OSA), n-dodecenyl succinic anhydride (n-DDSA) and n-octadecenyl succinic anhydrid...

  3. BIRCH XYLAN GRAFTED WITH PLA BRANCHES OF PREDICTABLE LENGTH

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    Johanna Persson,

    2012-06-01

    Full Text Available Birch xylan (4-O-methylglucuronoxylan isolated from a kraft cooking liquor was delignified and grafted with polylactide of predictable branch length. This graft copolymerization resulted in very high total yields, greater than 90%, and with less than 10% polylactide homopolymer byproducts. Mild reaction conditions (40°C, 5 to 120 minutes were used, which was believed to limit transesterification reactions and thus make it possible to reach good predictability of the polylactide branch length. The thermal properties of the polylactide-grafted xylan depended on the branch length. Short branches resulted in fully amorphous materials with a glass transition temperature of about 48 to 55°C, whereas long polylactide branches resulted in semi-crystalline materials with melting points of about 130°C. Using mixtures of L-lactide and D/L-lactide in the monomer feed further altered the thermal properties. The degradation temperatures of the polylactide-grafted xylans were higher than that of the unmodified xylan, with degradation temperatures of about 300°C and 250°C, respectively. Tensile testing showed increased elongation at break with increasing branch length. The proposed method thus enables tailor-making of copolymers with specific thermal and mechanical properties.

  4. THE INFLUENCE OF CATIONIZED BIRCH XYLAN ON WET AND DRY STRENGTH OF FINE PAPER

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    Janne Kataja-aho,

    2012-02-01

    Full Text Available Cationized birch xylan was prepared and its use as a papermaking chemical was evaluated. The focus was on studying the effects of cationized birch xylan on the wet and dry strength of fine paper. The results of the laboratory experiments show that the addition of 3 percent of cationized birch xylan to birch kraft pulp improved the initial wet strength of the web by 30 percent compared to base stock at a solids content of 55%. Furthermore, the tensile stiffness of the wet web increased by approximately a third and the dry tensile strength improved by 26%, while the dry elastic modulus was not changed. The improvements in the strength properties were clear when compared to the base stock, but not as high as achieved with conventionally used cationized starch. The difference between the xylan and starch is most likely due to the shorter polymer chain length of the cationized xylan.

  5. Molecular Dissection of Xylan Biosynthesis during Wood Formation in Poplar

    Institute of Scientific and Technical Information of China (English)

    Chanhui Lee; Quincy Teng; Ruiqin Zhong; Zheng-Hua Ye

    2011-01-01

    Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes involved in xylan biosynthesis during wood formation. In this report, we inves-tigated roles of poplar families GT43 and GT8 glycosyltransferases in xylan biosynthesis during wood formation. There exist seven GT43 genes in the genome of poplar (Populus trichocarpa), five of which, namely PtrGT43A, PtrGT43B,PtrGT43C, PtrGT43D, and PtrGT43E, were shown to be highly expressed in the developing wood and their encoded proteins were localized in the Golgi. Comprehensive genetic complementation coupled with chemical analyses demonstrated that overexpression of PtrGT43A/B/E but not PtrGT43C/D was able to rescue the xylan defects conferred by the Arabidopsis irx9mutant, whereas overexpression of PtrGT43C/D but not PtrGT43A/B/E led to a complementation of the xyian defects in the Arabidopsis irx14 mutant. The essential roles of poplar GT43 members in xylan biosynthesis was further substantiated by RNAi down-regulation of GT43B in the hybrid poplar (Populus alba x tremula)leading to reductions in wall thickness and xylan content in wood, and an elevation in the abundance of the xylan reducing end sequence. Wood digestibility analysis revealed that cellulase digestion released more glucose from the wood of poplar GT43B RNAi lines than the control wood, indicating a decrease in wood biomass recalcitrance. Furthermore, RNAi down-regulation of another poplar wood-associated glycosyltransferase, PoGT8D, was shown to cause decreases in wall thickness and xylan content as well as in the abundance of the xylan reducing end sequence. Together, these findings demonstrate that the poplar GT43 mem-bers form two functionally non-redundant groups, namely PtrGT43A/B/E as functional orthologs of Arabidopsis IRX9 and Ptr

  6. Molecular Dissection of Xylan Biosynthesis During Wood Formation in Poplar

    Science.gov (United States)

    Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes invo...

  7. Degradation kinetics of the main carbohydrates in birch wood during hot water extraction in a batch reactor at elevated temperatures.

    Science.gov (United States)

    Borrega, Marc; Nieminen, Kaarlo; Sixta, Herbert

    2011-11-01

    Hot water extraction of wood at elevated temperatures may be a suitable method to produce hemicellulose-lean pulps and to recover xylan-derived products from the water extract. In this study, water extractions of birch wood were conducted at temperatures between 180 and 240 °C in a batch reactor. Xylan was extensively removed, whereas cellulose was partly degraded only at temperatures above 180 °C. Under severe extraction conditions, acetic acid content in the water extract was higher than the corresponding amount of acetyl groups in wood. In addition to oligo- and monosaccharides, considerable amounts of furfural and 5-hydroxymethylfurfural (HMF) were recovered from the extracts. After reaching a maximum, the furfural yield remained constant with increasing extraction time. This maximum slightly decreased with increasing extraction temperature, suggesting the preferential formation of secondary degradation products from xylose. Kinetic models fitting experimental data are proposed to explain degradation and conversion reactions of xylan and glucan.

  8. METAL ION SORPTION TO BIRCH AND SPRUCE WOOD

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    Pingping Su,

    2012-02-01

    Full Text Available Sorption of metal ions from aqueous solutions to birch wood and spruce heartwood and sapwood has been studied. Functional groups in wood were determined by acid-base titrations. The sorption of metal ions to wood of the different tree species was investigated by a column chromatographic technique. The mechanism of sorption is mainly ion exchange by complexation of metal ions to the functional groups, e.g. carboxyl groups and phenolic hydroxyl groups, in the wood phase. By combination of the sorption experiments with four different metal ion mixtures, the following affinity order was established for spruce sapwood particles: Fe3+>>Pb2+>>Cu2+>>Fe2+>Cd2+>Zn2+>Ni2+>Mn2+≥Ca2+≥Sr2+≥Ba2+>>Mg2+>>K+>Na+≈Li+. For all three types of stemwood studied, the affinity orders were almost the same. The ion exchange properties of wood were comparable to those of a weakly acid cation exchanger. The affinity order obtained for the synthetic resin was quite similar to the order given above for wood. The metal sorption properties of wood materials imply that they could be a potential material for removal of metal ions from aqueous solutions.

  9. Chemical and physical characterization of emissions from birch wood combustion in a wood stove

    Science.gov (United States)

    Hedberg, Emma; Kristensson, Adam; Ohlsson, Michael; Johansson, Christer; Johansson, Per-Åke; Swietlicki, Erik; Vesely, Vaclav; Wideqvist, Ulla; Westerholm, Roger

    The purpose of this study was to characterize the emissions of a large number of chemical compounds emitted from birch wood combustion in a wood stove. Birch wood is widely used as fuel in Swedish household appliances. The fuel load was held constant during six experiments. Particles dust, range 30-330 for the former and 0.8±0.15 for the latter. The source profile of common elements emitted from wood burning differed from that found on particles at a street-level site or in long-distance transported particles. The ratio toluene/benzene in this study was found to be in the range 0.2-0.7, which is much lower than the ratio 3.6±0.5 in traffic exhaust emissions. Formaldehyde and acetone were the most abundant compounds among the volatile ketones and aldehydes. The emission factor varied between 180-710 mg/kg wood for formaldehyde and 5-1300 mg/kg wood for acetone. Of the organic acids analyzed (3,4,5)-trimethoxy benzoic acid was the most abundant compound. Of the PAHs reported, fluorene, phenanthrene, anthracene, fluoranthene and pyrene contribute to more than 70% of the mass of PAH. Of the elements analyzed, K and Si were the most abundant elements, having emission factors of 27 and 9 mg/kg wood, respectively. Although fluoranthene has a toxic equivalence factor of 5% of benzo(a)pyrene (B(a)P), it can be seen that the toxic potency of fluoranthene in wood burning emissions is of the same size as B(a)P. This indicates that the relative carcinogenic potency contribution of fluoranthene in wood smoke would be about 40% of B(a)P.

  10. Down-regulation of glycosyltransferase 8D genes in Populus trichocarpa caused reduced mechanical strength and xylan content in wood.

    Science.gov (United States)

    Li, Quanzi; Min, Douyong; Wang, Jack Peng-Yu; Peszlen, Ilona; Horvath, Laszlo; Horvath, Balazs; Nishimura, Yufuko; Jameel, Hasan; Chang, Hou-Min; Chiang, Vincent L

    2011-02-01

    Members of glycosyltransferase protein families GT8, GT43 and GT47 are implicated in the biosynthesis of xylan in the secondary cell walls of Arabidopsis. The Arabidopsis mutant irx8 has a 60% reduction in xylan. However, over-expression of an ortholog of Arabidopsis IRX8, poplar PoGT8D, in Arabidopsis irx8 mutant could not restore xylan synthesis. The functions of tree GT8D genes remain unclear. We identified two GT8 gene homologs, PtrGT8D1 and PtrGT8D2, in Populus trichocarpa. They are the only two GT8D members and are abundantly and specifically expressed in the differentiating xylem of P. trichocarpa. PtrGT8D1 transcript abundance was >7 times that of PtrGT8D2. To elucidate the genetic function of GT8D in P. trichocarpa, the expression of PtrGT8D1 and PtrGT8D2 was simultaneously knocked down through RNAi. Four transgenic lines had 85-94% reduction in transcripts of PtrGT8D1 and PtrGT8D2, resulting in 29-36% reduction in stem wood xylan content. Xylan reduction had essentially no effect on cellulose quantity but caused an 11-25% increase in lignin. These transgenics exhibit a brittle wood phenotype, accompanied by increased vessel diameter and thinner fiber cell walls in stem xylem. Stem modulus of elasticity and modulus of rupture were reduced by 17-29% and 16-23%, respectively, and were positively correlated with xylan content but negatively correlated with lignin quantity. These results suggest that PtrGT8Ds play key roles in xylan biosynthesis in wood. Xylan may be a more important factor than lignin affecting the stiffness and fracture strength of wood.

  11. Antioxidants from slow pyrolysis bio-oil of birch wood: Application for biodiesel and biobased lubricants

    Science.gov (United States)

    Birch wood was slowly pyrolyzed to produce bio-oil and biochar. Slow pyrolysis conditions including reaction temperature, residence time, and particle size of the feed were optimized to maximize bio-oil yield. Particle size had an insignificant effect, whereas yields of up to 56% were achieved using...

  12. Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood.

    Science.gov (United States)

    Derba-Maceluch, Marta; Awano, Tatsuya; Takahashi, Junko; Lucenius, Jessica; Ratke, Christine; Kontro, Inkeri; Busse-Wicher, Marta; Kosik, Ondrej; Tanaka, Ryo; Winzéll, Anders; Kallas, Åsa; Leśniewska, Joanna; Berthold, Fredrik; Immerzeel, Peter; Teeri, Tuula T; Ezcurra, Ines; Dupree, Paul; Serimaa, Ritva; Mellerowicz, Ewa J

    2015-01-01

    Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremula × tremuloides). PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen. PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68 kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.

  13. Influence of Biomass Pretreatment Process Time on Furfural Extraction from Birch Wood

    Science.gov (United States)

    Brazdausks, Prans; Puke, Maris; Vedernikovs, Nikolajs; Kruma, Irena

    2013-12-01

    Furfural is a biomass derived-chemical that can be used to replace petrochemicals. In this study, dilute sulphuric acid hydrolysis was used for hemicelluloses secession from birch wood. The reaction was investigated at different biomass treatment times (10-90 min, increasing it by 10 min). We found that the greatest amount of furfural 1.4-2.6%, which is 9.7-17.7% from theoretical possible yield, was formed in the first 30 min of the beginning of birch wood pentoses monosaccharide dehydration, but the greatest yield of furfural 10.3%, which is 70.0% from the theoretical yield, can be obtained after 90 min. Given that furfural yield generally does not exceed 50% from the theoretical amount, the result can be considered as very good.

  14. Energy resources of low-grade wood, small wood and waste materials. [Scots Pine; Norway Spruce; Birch

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, A.P.; Sviridyuk, E.P.

    1980-01-01

    An account is made of recent Finnish work on the potential of low-grade wood, small-dimension wood and waste material (of Scots pine, Norway spruce and birch) for power production, in the context of the current world energy crisis. The physical and economic aspects are considered, and the relevance of the Finnish research for the USSR is discussed. In 1978, wood accounted for only 1.4% of the energy balance of the USSR. Taking one t of 'standard fuel' as equal to 7000 kcal for the purposes of calculation, the energy potential of bark alone in the USSR is 13.6 million t/yr. (Refs. 6).

  15. Adhesive Through-Reinforcement Improves the Fracture Toughness of a Laminated Birch Wood Composite

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    Wenchang He

    2017-01-01

    Full Text Available In this paper we test the hypothesis that adhesive through-reinforcement in combination with glass-fibre reinforcement of adhesive bond lines will significantly improve the fracture toughness of a laminated birch wood composite. We test this hypothesis using a model composite consisting of perforated veneer that allowed a polyurethane adhesive to penetrate and reinforce veneers within the composite. Model composite specimens were tested for mode I fracture properties, and scanning electron microscopy was used to examine the microstructure of fracture surfaces. Our results clearly show that through-reinforcement, and also reinforcing adhesive bond lines with glass-fibre, significantly improved fracture toughness of the birch wood composite. Our results also indicate that improvements in fracture toughness depended on the level of reinforcement. Improvements in fracture toughness were related to the ability of the reinforcement to arrest crack development during fracture testing and the fibre bridging effect of glass-fibre in adhesive bond lines. We conclude that through-reinforcement is an effective way of improving the fracture toughness of laminated wood composites, but further research is needed to develop practical ways of creating such reinforcement in composites that more closely resemble commercial products.

  16. Characterization of lignin extracted from birch wood by a modified hydrotropic process.

    Science.gov (United States)

    Gabov, Konstantin; Gosselink, Richard J A; Smeds, Annika I; Fardim, Pedro

    2014-11-05

    In this work an environmentally friendly hydrotropic process was used to extract lignin from industrial birch wood chips. Two hydrotropic treatments were performed, a conventional and a modified process. The lignins were characterized using FTIR, pyrolysis-gas chromatography-mass spectrometry (pyrolysis-GC-MS), (31)P and (1)H-(13)C HSQC NMR, and size exclusion chromatography (SEC). The chemical (carbohydrates, extractives, etc.) and elemental compositions of the lignins were also determined. The yields of both lignins were 16.1% (dry wood basis), and the obtained lignins had very low contents of non-lignin compounds. The treatments resulted in significant changes of the structure of the lignins, a decrease in aliphatic hydroxyls and an increase in phenolic ones. The lignin isolated by the modified treatment underwent more substantial change than the reference one. It is believed that the data presented will facilitate utilization of hydrotropic lignin and promote the adoption of the hydrotropic process in the pulp and biorefinery industry.

  17. Research into the pyrolysis of pure cellulose, lignin, and birch wood flour in the China Lake entrained-flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, J.

    1980-06-01

    This experimental program used the China Lake entrained-flow pyrolysis reactor to briefly investigate the pyrolysis of pure cellulose, pure lignin, and birch wood flour. The study determined that the cellulose and wood flour do pyrolyze to produce primarily gaseous products containing significant amounts of ethylene and other useful hydrocarbons. During attempts to pyrolyze powdered lignin, the material melted and bubbled to block the reactor entrance. The pure cellulose and wood flour produced C/sub 2/ + yields of 12% to 14% by weight, which were less than yields from an organic feedstock derived from processed municipal trash. The char yields were 0.1% by weight from cellulose and 1.5% from birch wood flour - one to two orders of magnitude less than were produced from the trash-derived feedstock. In scanning electron microscope photographs, most of the wood flour char had a sintered and agglomerated appearance, although some particles retained the gross cell characteristics of the wood flour. The appearance of the char particles indicated that the material had once been molten and possibly vapor before it formed spheroidal particles about 1 ..mu..m diameter which agglomerated to form larger char particles. The ability to completely melt or vaporize lignocellulosic materials under conditions of high heating rates has now been demonstrated in a continuous flow reactor and promises new techniques for fast pyrolysis. This char was unexpectedly attracted by a magnet, presumably because of iron contamination from the pyrolysis reactor tube wall. The production of water-insoluble tars was negligible compared to the tars produced from trash-derived feedstock. The production of water-soluble organic materials was fairly low and qualitatively appeared to vary inversely with temperature. This study was of a preliminary nature and additional studies are necessary to optimize ethylene production from these feedstocks.

  18. The Effects of Surface Roughness on Adhesion Strength of Coated Ash (Fraxinus excelsior L. and Birch (Betula L. Wood

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    Justina VITOSYTĖ

    2012-12-01

    Full Text Available For the evaluation of surface roughness impact on adhesion properties, the samples of dried ash (Fraxinus excelsior L. and birch (Betula L. wood were used. Before wood finishing, the surfaces of the samples were sanded. In order to get different surface roughness the abrasive material of P80, P120, P150, P180, P220 and P240 grit was used. The parameters of surface roughness Ra, Rz and Rmax were measured in three directions: along the wood grain, across the grain and in the angle of 45º. Comparison of the results showed the non-linear dependency of roughness parameters. Afterwards the wood surface was coated with three different acrylic-polyurethane coating systems (1 layer of varnish without primer, 1 layer of primer and 1 layer of varnish, and 1 layer of primer and 2 layers of varnish. The adhesion strength was assessed using the pull-off method. Also the nature of the fracture was evaluated. It was determined that the peculiarities of surface roughness, coating system type and wood species signally results the values of the adhesion strength.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3094

  19. Seasonal dynamics of saproxylic beetles (Coleoptera occurring in decaying birch (Betula spp. wood in the Kampinos National Park

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    Sawoniewicz Michał

    2015-09-01

    Full Text Available The aim of the study was to identify the seasonal changes in the number of saproxylic beetles connected with birch in the Kampinos National Park. The research was conducted for 12 consecutive months in research areas representing 10 different site types. The beetles were collected from wood using photoeclectors. The largest number of species was collected in April and the lowest in January. An increase in number occurred during spring and summer months for species associated only with rotting wood, fructifications of tree fungi, the subcortical environment and hollows. In the same period the number of species not associated or potentially associated with decaying trees and wood decreased. During winter months, the differences in the number of trapped specimens were the smallest. The proportion of zoophagous species amongst the collected specimen increased in autumn and winter. The share of saprophagous species was the highest during the summer-autumn period and the share of mycetophages (jointly with myxomycophages was the highest during spring and summer. We distinguished two separate groups of Coleoptera with the first one (‘summer group’ including species trapped during late-spring and summer months, while the second one (‘winter group’ includes species found in autumn, winter and early-spring months. In the ‘summer group’, an average of 55.8 species was trapped each month with 331.2 specimen of Coleoptera, while in the ʻwinter group’ an average of 56.1 species with 228.4 Coleoptera specimen were caught.

  20. EFFECTS OF XYLAN IN EUCALYPTUS PULP PRODUCTION

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    Bianca Moreira Barbosa

    2016-06-01

    Full Text Available The search for a better use of wood in the pulp industry has fuelled interest in a more rational use of its components, particularly xylans. The impact of xylans removal and of xylans redeposition on pulp properties for tissue and P&W paper grades are discussed in this paper. Kraft pulp (15.6% xylans treatment with 10-70 g.L-1 NaOH resulted in pulps of 14.5-5.9% xylans. The treatments decreased pulp lignin and HexA contents and caused significant positive impact on subsequent oxygen delignification and ECF bleaching. Xylan removal decreased pulp beatability, water retention value and tensile index but increased drainability, water absorption capacity, capillarity Klemm and bulk. Overall, xylan depleted pulps showed almost ideal properties for tissue paper grade pulps. In a second step of the research, xylans extracted from unbleached (BXL and bleached eucalyptus pulps (WXL by cold caustic extraction (CCE were added to a commercial brown pulp in the oxygen delignification (O-stage and further bleached. Xylans deposition occurred at variable degree (up to 7% on pulp weight depending upon the O-stage reaction pH. Pulp bleachability was not impaired by WXL xylan deposition but slightly negatively affected by BXL xylans. Pulp beatability was improved by xylan deposition. The deposited xylans were quite stable across bleaching and beating, with the WXL xylans being more stable than the BXL ones. At low energy consumption, the deposited xylans improved pulp physical and mechanical properties. Xylans extraction by CCE with subsequent deposition onto pulp in the O-stage proved attractive for manufacturing high xylan P&W paper grades.

  1. Birch (Betula spp.) wood biochar is a potential soil amendment to reduce glyphosate leaching in agricultural soils.

    Science.gov (United States)

    Hagner, Marleena; Hallman, Sanna; Jauhiainen, Lauri; Kemppainen, Riitta; Rämö, Sari; Tiilikkala, Kari; Setälä, Heikki

    2015-12-01

    Glyphosate (N-(phosphonomethyl) glycine), a commonly used herbicide in agriculture can leach to deeper soil layers and settle in surface- and ground waters. To mitigate the leaching of pesticides and nutrients, biochar has been suggested as a potential soil amendment due to its ability to sorb both organic and inorganic substances. However, the efficiency of biochar in retaining agro-chemicals in the soil is likely to vary with feedstock material and pyrolysis conditions. A greenhouse pot experiment, mimicking a crop rotation cycle of three plant genera, was established to study the effects of pyrolysis temperature on the ability of birch (Betula sp.) wood originated biochar to reduce the leaching of (i) glyphosate, (ii) its primary degradation product AMPA and (iii) phosphorus from the soil. The biochar types used were produced at three different temperatures: 300 °C (BC300), 375 °C (BC375) and 475 °C (BC475). Compared to the control treatment without biochar, the leaching of glyphosate was reduced by 81%, 74% and 58% in BC300, BC375 and BC475 treated soils, respectively. The respective values for AMPA were 46%, 39% and 23%. Biochar had no significant effect on the retention of water-soluble phosphorus in the soil. Our results corroborate earlier findings on pesticides, suggesting that biochar amendment to the soil is a promising way to reduce also the leaching of glyphosate. Importantly, the ability of biochar to adsorb agro-chemicals depends on the temperature at which feedstock is pyrolysed.

  2. Numerical responses of saproxylic beetles to rapid increases in dead wood availability following geometrid moth outbreaks in sub-arctic mountain birch forest.

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    Ole Petter Laksforsmo Vindstad

    Full Text Available Saproxylic insects play an important part in decomposing dead wood in healthy forest ecosystems, but little is known about their role in the aftermath of large-scale forest mortality caused by pest insect outbreaks. We used window traps to study short-term changes in the abundance and community structure of saproxylic beetles following extensive mortality of mountain birch in sub-arctic northern Norway caused by an outbreak of geometrid moths. Three to five years after the outbreak, the proportion of obligate saproxylic individuals in the beetle community was roughly 10% higher in forest damaged by the outbreak than in undamaged forest. This was mainly due to two early-successional saproxylic beetle species. Facultative saproxylic beetles showed no consistent differences between damaged and undamaged forest. These findings would suggest a weak numerical response of the saproxylic beetle community to the dead wood left by the outbreak. We suggest that species-specific preferences for certain wood decay stages may limit the number of saproxylic species that respond numerically to an outbreak at a particular time, and that increases in responding species may be constrained by limitations to the amount of dead wood that can be exploited within a given timeframe (i.e. satiation effects. Low diversity of beetle species or slow development of larvae in our cold sub-arctic study region may also limit numerical responses. Our study suggests that saproxylic beetles, owing to weak numerical responses, may so far have played a minor role in decomposing the vast quantities of dead wood left by the moth outbreak.

  3. Effect of wood ash on leaf and shoot anatomy, photosynthesis and carbohydrate concentrations in birch on a cutaway peatland.

    Science.gov (United States)

    Aguraijuja, Karin; Klõšeiko, Jaan; Ots, Katri; Lukjanova, Aljona

    2015-07-01

    Trees in cutaway peatland are growing in difficult conditions. Fertilization with nutrient-rich wood ash helps improve growth conditions. Photosynthesis and carbohydrate concentration along leaf anatomy were studied on plots treated with 10 and 5 t ha(-1) wood ash (WA10 and WA5) and on untreated (Control) plot to explain the physiological background of the differences in tree growth. The leaves from WA10 had the largest leaf area, total thickness, the thickest mesophyll and also significantly larger average values of all anatomical parameters of the shoots. The photosynthetic assimilation was significantly higher on treated plots at 200 and 400 ppm CO2 levels. In leaves on the treated plots, the sucrose concentration was lower while that of starch was higher than in trees on untreated soil. The differences in the maximum photosynthesis were relatively small. At unit ground, the leaf area provided for a wood ash-treated tree an efficient surface for CO2 assimilation, light interception and some starch storage during the growing period.

  4. Draft genome sequence of Sugiyamaella xylanicola UFMG-CM-Y1884(T), a xylan-degrading yeast species isolated from rotting wood samples in Brazil.

    Science.gov (United States)

    Batista, Thiago M; Moreira, Rennan G; Hilário, Heron O; Morais, Camila G; Franco, Glória R; Rosa, Luiz H; Rosa, Carlos A

    2017-03-01

    We present the draft genome sequence of the type strain of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884(T) (= UFMG-CA-32.1(T) = CBS 12683(T)), a xylan-degrading species capable of fermenting d-xylose to ethanol. The assembled genome has a size of ~ 13.7 Mb and a GC content of 33.8% and contains 5971 protein-coding genes. We identified 15 genes with significant similarity to the d-xylose reductase gene from several other fungal species. The draft genome assembled from whole-genome shotgun sequencing of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884(T) (= UFMG-CA-32.1(T) = CBS 12683(T)) has been deposited at DDBJ/ENA/GenBank under the accession number MQSX00000000 under version MQSX01000000.

  5. Draft genome sequence of Sugiyamaella xylanicola UFMG-CM-Y1884T, a xylan-degrading yeast species isolated from rotting wood samples in Brazil

    Directory of Open Access Journals (Sweden)

    Thiago M. Batista

    2017-03-01

    Full Text Available We present the draft genome sequence of the type strain of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884T (=UFMG-CA-32.1T = CBS 12683T, a xylan-degrading species capable of fermenting d-xylose to ethanol. The assembled genome has a size of ~13.7 Mb and a GC content of 33.8% and contains 5971 protein-coding genes. We identified 15 genes with significant similarity to the d-xylose reductase gene from several other fungal species. The draft genome assembled from whole-genome shotgun sequencing of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884T (=UFMG-CA-32.1T = CBS 12683T has been deposited at DDBJ/ENA/GenBank under the accession number MQSX00000000 under version MQSX01000000.

  6. Characterisation of complex xylo-oligosaccharides from xylan rich by-products

    NARCIS (Netherlands)

    Kabel, M.A.

    2002-01-01

    Hydrolysates obtained by hydrothermal treatment of four xylan rich by-products (wheat bran, brewery's spent grain, corn cobs and Eucalyptus wood) were characterised. Depending on the feedstock material studied, the xylan originally present differed in substitution with arabinose, 4- O -methylglucuro

  7. Hydrothermally treated xylan rich by-products yield different classes of xylo-oligosaccharides

    NARCIS (Netherlands)

    Kabel, M.A.; Carvalheiro, F.; Garrote, G.; Avgerinos, E.; Koukios, E.; Parajo, J.C.; Girio, M.

    2002-01-01

    Four xylan rich by-products, namely wheat bran, brewery's spent grain, corn cobs and Eucalyptus wood, were characterised and subjected to a mild hydrothermal treatment in order to release and degrade the xylan from the starting materials. The chemical characterisation of the feedstock materials, wit

  8. Lignin profiling in extracted xylans by size-exclusion chromatography.

    Science.gov (United States)

    Hutterer, Christian; Schild, Gabriele; Kliba, Gerhard; Potthast, Antje

    2016-10-20

    Utilization of the polymeric parts of lignocellulose is expected to gain increasing importance in future biorefinery scenarios. In that respect, a particular focus is placed on hemicelluloses from different wood species gained from an industrially feasible upgrading step in the production of dissolving pulps from paper pulps. During alkaline post-extractions for hemicellulose removal, residual lignins are extracted as well. They are either covalently linked to the extracted hardwood xylans or simply co-dissolved in the alkaline lye. In order to better describe the lignin in xylan containing lyes, a method for lignin profiling was set up by hyphenating size-exclusion chromatography of xylans with UV detection which facilitates visualization of the residual lignin distribution. Simultaneous lignin quantification was achieved with lignin standards prepared from Kraft cooking liquors. The setup presented may serve as advanced characterization for novel xylan products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Inter- and intra-specific variation in stem phloem phenolics of paper birch (Betula papyrifera) and European white birch (Betula pendula).

    Science.gov (United States)

    Muilenburg, V L; Phelan, P L; Bonello, P; Herms, D A

    2011-11-01

    Outbreaks of bronze birch borer (BBB) (Agrilus anxius), a wood-boring beetle endemic to North America, have been associated with widespread mortality of birch (Betula spp.). There is substantial inter- and intra-specific variation in birch resistance to BBB. Species endemic to North America, such as paper birch (B. papyrifera), have coevolved with BBB and are more resistant than European and Asian birch species, such as European white birch (B. pendula), which lack an evolutionary history with BBB. Borer larvae feed on stem phloem tissue. Therefore, in search of potential resistance mechanisms against BBB, we compared the constitutive phenolic profile of stem phloem tissue of paper birch with that of European white birch. We also analyzed intraspecific variation in phenolic composition among clones and/or half-siblings of both species. Three phenolics (coumaroylquinic acid, betuloside pentoside A, and a diarylheptanoid hexoside) were detected only in paper birch, and concentrations of six other phenolics were significantly higher in paper birch. These differences may contribute to the high resistance of paper birch to BBB relative to European white birch. There was significant intraspecific variation in four of 17 phenolics found in paper birch and in five of 14 found in European white birch, but clones and half-siblings within each species could not be distinguished by phenolic composition using multivariate analysis.

  10. The mechanism of xylans removal during hydrothermal pretreatment of poplar fibers investigated by immunogold labeling.

    Science.gov (United States)

    Ma, Jing; Ji, Zhe; Chen, Jia C; Zhou, Xia; Kim, Yoon S; Xu, Feng

    2015-07-01

    Hydrothermal pretreatment initially removed the lignin-free xylan from the middle layer of secondary wall, followed by the lignin-bound xylan, but the cellulose-bound xylan was seldom removed by this pretreatment. An in-depth understanding of the mechanism of xylan removal during hydrothermal pretreatment (HTP) of wood is critical for cost-effective conversion of lignocellulosic biomass to biofuels. Several studies demonstrated the kinetics and mechanism of xylan removal during HTP on molecular scale, but the dissolution mechanism of xylan during HTP remains unclear at ultra-structural level. Our study investigated changes in the micro-distribution of xylan in poplar fiber cell walls during HTP by transmission electron microscopy (TEM) in combination with immunogold labeling. The study revealed that HTP caused greater decline in the density of xylan labeling in the S2 layer of fiber wall than in the S1 layer. There was a greater loss in the density of xylan labeling during HTP in the delignified and enzymatically treated fibers compared to untreated fibers. We propose that in the initial stages of HTP lignin-free xylan in the S2 layer was more readily hydrolyzed than in the S1 layer by hydronium ions. With increasing pretreatment time, the xylan covalently bound to lignin was also removed from the S2 layer due to the dissolution of lignin. The xylan tightly bound to cellulose was seldom removed during HTP, but was hydrolyzed in subsequent enzymatic treatment. This TEM-immunolabeling investigation reveals the manner in which different xylan fractions are removed from fiber cell wall during HTP, and we expect the information to be helpful in developing processes tailored for more effective conversion of cellulosic biomass into fermentable sugars.

  11. Digestion of wood-based hemicellulose extracts as screened by in vitro gas production method and verified in vivo using sheep

    Directory of Open Access Journals (Sweden)

    Marketta Rinne

    2016-03-01

    Full Text Available The objective of the present study was to evaluate the potential of pressurized hot water extracted hemicellulose fractions from various wood species as feeds for ruminants. In Experiment 1, the fermentability of several hemicellulose extracts was screened using an in vitro gas production method. The samples were extracted from spruce (Picea abies including mainly galactoglucomannan (GGM, from birch (Betula pendula consisting mainly of xylan and from larch (Larix sibirica consisting mainly of arabinogalactan. The GGM and xylan samples were readily fermented by rumen microbes while arabinogalactan was not. Based on the in vitro study, GGM was chosen for an in vivo digestibility trial using sheep, where it was fed at increasing proportions of diet dry matter (0, 47, 94 and 141 g kg-1 in a Latin Square design. The in vivo organic matter digestibility of GGM was relatively low, 0.58, but PHWE extracted hemicellulose has some potential as a feed for ruminants.

  12. Wood

    DEFF Research Database (Denmark)

    Unterrainer, Walter

    2014-01-01

    come from? How is it harvested? How is it manufactured and treated ? How are the buildings detailed and protected against weather during construction to keep them dry and make them long-life ? In a period of climate change, forests are the last lungs of the planet to sequestrate CO2. Their global size......Wood – a sustainable building material ? For thousands of years and all over the planet, wood has been used as a building material and exciting architecture has been created in wood. The fantastic structural, physical and aesthetic properties of the material as well as the fact that wood...

  13. Animal damage to birch

    Science.gov (United States)

    James S. Jordan; Francis M. Rushmore

    1969-01-01

    A relatively few animal species are responsible for most of the reported damage to the birches. White-tailed deer, yellow-bellied sapsuckers, porcupines, moose, and hares are the major animals involved. We will review reports of damage, discuss the underlying causes, and describe possible methods of control. For example, heavy deer browsing that eliminates birch...

  14. A review of bronze birch borer (Coleoptera: Buprestidae) life history, ecology, and management.

    Science.gov (United States)

    Muilenburg, Vanessa L; Herms, Daniel A

    2012-12-01

    Bronze birch borer (Agrilus anxius Gory) (Coleoptera: Buprestidae), a specialist wood-borer endemic to North America, is prone to periodic outbreaks that have caused widespread mortality of birch (Betula spp.) in boreal and north temperate forests. It is also the key pest of birch in ornamental landscapes. Amenity plantings have extended the distribution of birch in North America, for which we report an updated map. Life history and phenology also are summarized. Larvae feed primarily on phloem tissue of stems and branches, which can girdle and kill trees. Stressors such as drought, elevated temperature, and defoliation predispose trees to bronze birch borer colonization and trigger outbreaks, which implicates the availability of suitable host material in the bottom-up regulation of populations. Stress imposed by climate change may increase the frequency of outbreaks and alter the distribution of birch. Bronze birch borer has a diverse array of natural enemies, but their role in top-down population regulation has not been studied. There is substantial interspecific variation in resistance to this insect. North American species share a coevolutionary history with bronze birch borer and are much more resistant than Eurasian species, which are evolutionarily naïve. Potential resistance mechanisms are reviewed. The high susceptibility of Eurasian birch species and climatic similarities of North America and Eurasia create high risk of widespread birch mortality in Eurasia if the borer was inadvertently introduced. Bronze birch borer can be managed in amenity plantings through selection of resistant birch species, plant health care practices, and insecticides.

  15. Wood

    DEFF Research Database (Denmark)

    Unterrainer, Walter

    2014-01-01

    has shrinked by 30% since the preindustrial times and in countries like China (with a historic tradition for wooden architecture) we could observe enormous desertification. What does this mean for the use of wood in modern architecture ? A critical reflection is needed. In too many cases...

  16. Wood

    Science.gov (United States)

    David W. Green; Robert H. White; Antoni TenWolde; William Simpson; Joseph Murphy; Robert J. Ross; Roland Hernandez; Stan T. Lebow

    2006-01-01

    Wood is a naturally formed organic material consisting essentially of elongated tubular elements called cells arranged in a parallel manner for the most part. These cells vary in dimensions and wall thickness with position in the tree, age, conditions of growth, and kind of tree. The walls of the cells are formed principally of chain molecules of cellulose, polymerized...

  17. Xylan polysaccharides fabricated into nanofibrous substrate for myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, J., E-mail: nnijrv@nus.edu.sg; Rajeswari, R.; Shayanti, M.; Sridhar, R.; Sundarrajan, S.; Balamurugan, R.; Ramakrishna, S.

    2013-04-01

    Myocardial infarction, a main cause of heart failure, leads to loss of cardiac tissue impairment of left ventricular function. Repair of diseased myocardium with in vitro engineered cardiac muscle patch/injectable biopolymers with cells may become a viable option for myocardial infarction. We attempted to solve these problems by in vitro study by selecting a plant based polysaccharides beech wood Xylan for the normal functioning of infarcted myocardium. The present study fabricated Xylan based nanofibrous scaffolds cross-linked with glutaraldehyde (Glu) vapors for 24 h, 48 h and 1% Glu blended fibers for the culture of neonatal rat cardiac cells for myocardial infarction. These nanofibers were characterized by SEM, FT-IR, tensile testing and cell culture studies for the normal expression of cardiac proteins. The observed results showed that the Xylan/polyvinyl alcohol (PVA) 24 h Glu vapor cross-linked nanofibers (427 nm) having mechanical strength of 2.43 MPa and Young modulus of 3.74 MPa are suitable for the culture of cardiac cells. Cardiac cells proliferation increased only by 11% in Xylan/PVA 24 h Glu cross-linked nanofibers compared to control tissue culture plate (TCP). The normal cardiac cell morphology was observed in 24 h cross-linked Xylan/PVA nanofibers but 48 h cross-linked fibers cell morphology was changed to flattened and elongated on the fibrous surfaces. Confocal analysis for cardiac expression proteins actinin, connexin 43 was observed normally in 24 h Glu cross-linked nanofibers compared to all other nanofibrous scaffolds. The fabricated Xylan/PVA nanofibrous scaffold may have good potential for the normal functioning of infarcted myocardium. - Highlights: ► Fabrication of polysaccharides Xylan/PVA nanofibers for cardiac tissue engineering ► Nanofibers characterized by SEM, FT-IR, tensile testing and cell culture studies ► Isolation of cardiac cells and cultured on Xylan/PVA nanofibrous scaffolds ► Cultured cells on 24 h Glu cross

  18. Xylan derivatives and their application potential - mini-review of own results.

    Science.gov (United States)

    Petzold-Welcke, Katrin; Schwikal, Katrin; Daus, Stephan; Heinze, Thomas

    2014-01-16

    The chemical modification of xylan is a promising path to new biopolymer ethers and esters with specific properties depending on the functional groups, the degree of substitution, and the substitution pattern. The reaction of 4-O-methylglucuronoxylan (GX) from birch with sodium monochloroacetate and 2,3-epoxypropyltrimethylammonium chloride in aqueous sodium hydroxide/slurry medium is described. The influence of the conditions of activation on product structure and properties are discussed in some detail. Methylation of GX was investigated under completely heterogeneous conditions or starting with dissolved polymer using methyl halides as reagents in the presence of NaOH. An activation of the biopolymer has been carried out before the reaction to enhance the accessibility of the reagents. Furthermore, novel xylan esters were efficiently synthesized by conversion of the hemicellulose with furan- and pyroglutamic acid as well as ibuprofen and N,N'-carbonyldiimidazole as activating agent under homogeneous conditions in dimethyl sulfoxide. This conditions are also appropriate to synthesize novel xylan ester containing xylan-4-[N,N,N-trimethylammonium]butyrate chloride moieties. Homogeneous syntheses of xylan sulfates could be carried out in a N,N-dimethylformamide (DMF)/LiCl as solvent applying sulfur trioxide complexes with DMF or pyridine. Advanced analytical techniques including NMR spectroscopy, HPLC, scanning electron microscopy, rheology, measurements of turbidity and surface tension allow description of structure-property-relationships; selected results will be briefly discussed. Xylan esters may form spherical nanoparticles of a size down to 60 nm and a narrow particle size distribution applying a simple dialysis process and may be used for drug delivery applications. For cationic xylan derivatives a wide range of applications as paper strength additives, flocculation aids, and antimicrobial agents are proposed.

  19. Winter Birch Trees

    Science.gov (United States)

    Sweeney, Debra; Rounds, Judy

    2011-01-01

    Trees are great inspiration for artists. Many art teachers find themselves inspired and maybe somewhat obsessed with the natural beauty and elegance of the lofty tree, and how it changes through the seasons. One such tree that grows in several regions and always looks magnificent, regardless of the time of year, is the birch. In this article, the…

  20. Investigating Mass Transport Limitations on Xylan Hydrolysis During Dilute Acid Pretreatment of Poplar

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Ashutosh; Pilath, Heid M.; Parent, Yves; Chatterjee, Siddharth G.; Donohoe, Bryon S.; Yarbrough, John M.; Himmel, Michael E.; Nimlos, Mark R.; Johnson, David K.

    2014-04-28

    Mass transport limitations could be an impediment to achieving high sugar yields during biomass pretreatment and thus be a critical factor in the economics of biofuels production. The objective of this work was to study the mass transfer restrictions imposed by the structure of biomass on the hydrolysis of xylan during dilute acid pretreatment of biomass. Mass transfer effects were studied by pretreating poplar wood at particle sizes ranging from 10 micrometers to 10 mm. This work showed a significant reduction in the rate of xylan hydrolysis in poplar when compared to the intrinsic rate of hydrolysis for isolated xylan that is possible in the absence of mass transfer. In poplar samples we observed no significant difference in the rates of xylan hydrolysis over more than two orders of magnitude in particle size. It appears that no additional mass transport restrictions are introduced by increasing particle size from 10 micrometers to 10 mm. This work suggests that the rates of xylan hydrolysis in biomass particles are limited primarily by the diffusion of hydrolysis products out of plant cell walls. A mathematical description is presented to describe the kinetics of xylan hydrolysis that includes transport of the hydrolysis products through biomass into the bulk solution. The modeling results show that the effective diffusion coefficient of the hydrolysis products in the cell wall is several orders of magnitude smaller than typical values in other applications signifying the role of plant cell walls in offering resistance to diffusion of the hydrolysis products.

  1. Effect of different steam explosion conditions on methane potential and enzymatic saccharification of birch.

    Science.gov (United States)

    Vivekanand, Vivekanand; Olsen, Elisabeth F; Eijsink, Vincent G H; Horn, Svein J

    2013-01-01

    Birch (Betula pubescens) was steam exploded at 13 different conditions with temperatures ranging from 170 to 230 °C and residence times ranging from 5 to 15 min. Increasing severity in the pretreatment led to degradation of xylan and formation of pseudo-lignin. The effect of the pretreatments was evaluated by running enzymatic saccharification and anaerobic digestion followed by analysis of sugar and methane yields, respectively. Enzymatically released glucose increased with pretreatment severity up to 220 °C for 10 min and levels of solubilized glucose reached 97% of the theoretical maximum. The highest methane yield (369 mL gVS(-1)) was obtained at a severity factor of 4.5 and this yield was 1.8 times higher than the yield from untreated birch. Enzymatic glucose yields and methane yields were generally correlated. The results indicate that steam-exploded birch can be effectively converted to either glucose or methane.

  2. Probing Xylan-Specific Raman Bands for Label-Free Imaging Xylan in Plant Cell Wall

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yining; Yarbrough, John M.; Mittal, Ashutosh; Tucker, Melvin P.; Vinzant, Todd; Himmel, Michael E.

    2015-06-15

    Xylan constitutes a significant portion of biomass (e.g. 22% in corn stover used in this study). Xylan is also an important source of carbohydrates, besides cellulose, for renewable and sustainable energy applications. Currently used method for the localization of xylan in biomass is to use fluorescence confocal microscope to image the fluorescent dye labeled monoclonal antibody that specifically binds to xylan. With the rapid adoption of the Raman-based label-free chemical imaging techniques in biology, identifying Raman bands that are unique to xylan would be critical for the implementation of the above label-free techniques for in situ xylan imaging. Unlike lignin and cellulose that have long be assigned fingerprint Raman bands, specific Raman bands for xylan remain unclear. The major challenge is the cellulose in plant cell wall, which has chemical units highly similar to that of xylan. Here we report using xylanase to specifically remove xylan from feedstock. Under various degree of xylan removal, with minimum impact to other major cell wall components, i.e. lignin and cellulose, we have identified Raman bands that could be further tested for chemical imaging of xylan in biomass in situ.

  3. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose.

    Science.gov (United States)

    Busse-Wicher, Marta; Li, An; Silveira, Rodrigo L; Pereira, Caroline S; Tryfona, Theodora; Gomes, Thiago C F; Skaf, Munir S; Dupree, Paul

    2016-08-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls.

  4. ALKALINE PRETREATMENT OF SPRUCE AND BIRCH TO IMPROVE BIOETHANOL AND BIOGAS PRODUCTION

    Directory of Open Access Journals (Sweden)

    Azam Jeihanipour

    2010-05-01

    Full Text Available Alkaline pretreatment with NaOH under mild operating conditions was used to improve ethanol and biogas production from softwood spruce and hardwood birch. The pretreatments were carried out at different temperatures between minus 15 and 100ºC with 7.0% w/w NaOH solution for 2 h. The pretreated materials were then enzymatically hydrolyzed and subsequently fermented to ethanol or anaerobically digested to biogas. In general, the pretreatment was more successful for both ethanol and biogas production from the hardwood birch than the softwood spruce. The pretreatment resulted in significant reduction of hemicellulose and the crystallinity of cellulose, which might be responsible for improved enzymatic hydrolyses of birch from 6.9% to 82.3% and spruce from 14.1% to 35.7%. These results were obtained with pretreatment at 100°C for birch and 5°C for spruce. Subsequently, the best ethanol yield obtained was 0.08 g/g of the spruce while pretreated at 100°C, and 0.17 g/g of the birch treated at 100°C. On the other hand, digestion of untreated birch and spruce resulted in methane yields of 250 and 30 l/kg VS of the wood species, respectively. The pretreatment of the wood species at the best conditions for enzymatic hydrolysis resulted in 83% and 74% improvement in methane production from birch and spruce.

  5. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xianai [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Duygu, E-mail: dkocaefe@uqac.ca [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Yasar [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Boluk, Yaman [University of Alberta, 3-142 Markin/CNRL Natural Resources Engineering Facility, Edmonton, Alberta, T6G 2W2 (Canada); Krause, Cornelia [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Investigate detailed structural changes of heat-treated wood due to weathering. Black-Right-Pointing-Pointer Identify connection between physical structural changes and chemical degradation. Black-Right-Pointing-Pointer Study effect of heat treatment conditions on weathering degradation process. - Abstract: Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  6. Characterization of Spruce Xylan and Its Potential for Strength Improvement

    OpenAIRE

    Jansson, Zheng

    2013-01-01

    Xylan dissolved during kraft cooking and later redeposited on fibre surfaces has been shown to give higher pulp yield and better strength properties. This is economically interesting from an industrial point of view. Many studies have been done to investigate xylan behaviour during kraft cooking, to discover the xylan-cellulose attachment mechanism, to find the optimal xylan retention or adsorption process, and to discover relations between xylan structure and strength enhancement. Most of th...

  7. EFFECT OF THERMAL TREATMENT ON THE CHEMICAL COMPOSITION AND MECHANICAL PROPERTIES OF BIRCH AND ASPEN

    Directory of Open Access Journals (Sweden)

    Duygu Kocaefe

    2008-05-01

    Full Text Available The high temperature treatment of wood is one of the alternatives to chemical treatment. During this process, the wood is heated to higher temperatures than those of conventional drying. The wood structure changes due to decomposition of hemicelluloses, ramification of lignin, and crystallization of cellulose. The wood becomes less hygroscopic. These changes improve the dimensional stability of wood, increase its resistance to micro-organisms, darken its color, and modify its hardness. However, wood also might loose some of its elasticity. Consequently, the heat treatment conditions have to be optimized. Therefore, it is important to understand the transformation of the chemical structure of wood caused by the treatment. In this study, the modification of the surface composition of the wood was followed with Fourier transform infrared spectroscopy (FTIR and inverse gas chromatography (IGC under different experimental conditions. The effect of maximum treatment temperatures on the chemical composition of Canadian birch and aspen as well as the correlations between their chemical transformation and different mechanical properties are presented. FTIR analysis results showed that the heat treatment affected the chemical composition of birch more compared to that of aspen. The results of IGC tests illustrated that the surfaces of the aspen and birch became more basic with heat treatment. The mechanical properties were affected by degradation of hemicellulose, ramification of lignin and cellulose crystallization.

  8. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Science.gov (United States)

    Huang, Xianai; Kocaefe, Duygu; Kocaefe, Yasar; Boluk, Yaman; Krause, Cornélia

    2013-01-01

    Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  9. Two Arabidopsis proteins synthesize acetylated xylan in vitro

    National Research Council Canada - National Science Library

    Urbanowicz, Breeanna R; Peña, Maria J; Moniz, Heather A; Moremen, Kelley W; York, William S

    2014-01-01

    .... Phenotypic analysis of these mutants has implicated many proteins in xylan biosynthesis; however, the enzymes directly responsible for elongation and acetylation of the xylan backbone have not been unambiguously identified...

  10. Efficacy of recombinant birch pollen vaccine for the treatment of birch-allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Pauli, Gabrielle; Larsen, Tina H; Rak, Sabina

    2008-01-01

    BACKGROUND: Recombinant DNA technology has the potential to produce allergen-specific immunotherapy vaccines with defined composition. OBJECTIVE: To evaluate the effectiveness of a new recombinant birch pollen allergen vaccine in patients with birch pollen allergy. METHODS: A multicenter......, randomized, double-blind, placebo-controlled trial was undertaken to compare the following 3 vaccines in 134 adults with birch pollen allergy: recombinant birch pollen allergen vaccine (rBet v 1a), licensed birch pollen extract, natural purified birch pollen allergen (nBet v 1), and placebo. Patients...

  11. Analysis of aspen-and-birch separated small woods’ vegetation in North Steppe of Ukraine

    Directory of Open Access Journals (Sweden)

    N. M. Nazarenko

    2010-09-01

    Full Text Available Conducted analysis of forest vegetation has allowed selecting and specifying classification and typological units of the aspen-and-birch separated small woods, which have statistically significant difference of ecotopic and coenotic parameters. Those parameters of studied forest ecosystems are characterised. Existence of the lines of hygrogenic and edaphogenic substitution, and succession rows are described. Phytoindication description of ecological factors’ pivotal conditions is presented. Driving factors determining parameters, structure and composition of the aspen-and-birch forest ecosystems are diminishing soil moisture, increasing annual temperatures amplitude and soil acidity.

  12. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose1[OPEN

    Science.gov (United States)

    Li, An; Gomes, Thiago C.F.

    2016-01-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls. PMID:27325663

  13. Three novel rice genes closely related to the Arabidopsis IRX9, IRX9L, and IRX14 genes and their roles in xylan biosynthesis

    Directory of Open Access Journals (Sweden)

    Dawn eChiniquy

    2013-04-01

    Full Text Available Xylan is the second most abundant polysaccharide on Earth, and represents a major component of both dicot wood and the cell walls of grasses. Much knowledge has been gained from studies of xylan biosynthesis in the model plant, Arabidopsis. In particular, the irregular xylem (irx mutants, named for their collapsed xylem cells, have been essential in gaining a greater understanding of the genes involved in xylan biosynthesis. In contrast, xylan biosynthesis in grass cell walls is poorly understood. We identified three rice genes Os07g49370 (OsIRX9, Os01g48440 (OsIRX9L, and Os06g47340 (OsIRX14, from glycosyltransferase family 43 as putative orthologs to the putative β-1,4-xylan backbone elongating Arabidopsis IRX9, IRX9L, and IRX14 genes, respectively. We demonstrate that the overexpression of the closely related rice genes, in full or partly complement the two well-characterized Arabidopsis irregular xylem (irx mutants: irx9 and irx14. Complementation was assessed by measuring dwarfed phenotypes, irregular xylem cells in stem cross sections, xylose content of stems, xylosyltransferase activity of stems, and stem strength. The expression of OsIRX9 in the irx9 mutant resulted in xylosyltransferase activity of stems that was over double that of wild type plants, and the stem strength of this line increased to 124% above that of wild type. Taken together, our results suggest that OsIRX9/OsIRX9L, and OsIRX14, have similar functions to the Arabidopsis IRX9 and IRX14 genes, respectively. Furthermore, our expression data indicate that OsIRX9 and OsIRX9L may function in building the xylan backbone in the secondary and primary cell walls, respectively. Our results provide insight into xylan biosynthesis in rice and how expression of a xylan synthesis gene may be modified to increase stem strength.

  14. Ecological and phytopathological status of birch stands on the territory of Krasnoyarsk group of districts

    Directory of Open Access Journals (Sweden)

    A. I. Tatarintsev

    2015-04-01

    Full Text Available According to inspection data, the health and vital status of birch (Betula pendula Roth. stands in Krasnoyarsk group of lands (southern part of Central Siberia were estimated (established as satisfactory in general; about half of birch stands near urbanized areas were weakened. The condition of stands decreased significantly with increased recreation use, the effect of technogenic pollution was negligible. The most valuable (important representatives of pathogenic biota identified on birch trees were infestations of necrotic cancer and rot diseases. In birch stands the bacterial dropsy was found to be widespread (agent of infection – Erwinia multivora Scz.-Parf, occurrence of the disease ranged from a single ill tree up to 10–38 % of the stands. The birch stands in taiga areas were affected to a greater extent than in forest-steppe; there were high yield class stands on moist soils. Prevalence of bacteriosis rose with increasing stand age and density and not dependent on recreation use level. Trees with dropsy are dead in fact or potentially. In taiga birch forests the infection and rot of roots was caused by honey agaric (Armillaria mellea sensu lato, that lead to single or, rarely, group tree drying and the fungus usually eliminated already weakened trees. Wood biomass was destroyed by complex of aphyllophorous Hymenomycetes, their hemiparasitic species caused stem rots that decreased stand marketability and also resulted in rot-realated wind-break accumulation. Occurrence of rot was significantly higher in second growth birch stands, possibly above 20 %; the relationship between rot prevalence and forest assessment was not revealed.

  15. Wood for sound.

    Science.gov (United States)

    Wegst, Ulrike G K

    2006-10-01

    The unique mechanical and acoustical properties of wood and its aesthetic appeal still make it the material of choice for musical instruments and the interior of concert halls. Worldwide, several hundred wood species are available for making wind, string, or percussion instruments. Over generations, first by trial and error and more recently by scientific approach, the most appropriate species were found for each instrument and application. Using material property charts on which acoustic properties such as the speed of sound, the characteristic impedance, the sound radiation coefficient, and the loss coefficient are plotted against one another for woods. We analyze and explain why spruce is the preferred choice for soundboards, why tropical species are favored for xylophone bars and woodwind instruments, why violinists still prefer pernambuco over other species as a bow material, and why hornbeam and birch are used in piano actions.

  16. Producing wood-based nanomaterials by rapid fractionation of wood at 80 °C using a recyclable acid hydrotrope

    Science.gov (United States)

    Huiyang Bian; Liheng Chen; R. Gleisner; Hongqi Dai; J. Y. Zhu

    2017-01-01

    Here we report the unparalleled performance of a novel acid hydrotrope, p-toluenesulfonic acid (p-TsOH) for the rapid and nearly-complete dissolution of wood lignin below the boiling temperature of water. Up to 85% of birch wood lignin can be solubilized at 80° C for 20 minutes. Similar degrees of delignification can only be...

  17. Investigation of wood combustion in the high-enthalpy oxidizer flow

    Science.gov (United States)

    Reshetnikov, S. M.; Zyryanov, I. A.; Budin, A. G.; Pozolotin, A. P.

    2017-01-01

    The experimental data of wood combustion in the high-enthalpy oxidizer flowresearch is presented. Combustion laws of two wood species (pine and birch) in a hybrid rocket engine (HRE) are obtained. Heat flows from the flame to the condensed phase surface are defined. The prospects of the wood use in the HRE (based on thrust characteristics) are shown.

  18. The problem of improvement birch stand productivity in forest steppe of Cis-Urals

    Directory of Open Access Journals (Sweden)

    S. V. Zalesov

    2016-06-01

    Full Text Available The article deals with birch stands of the forest steppes in Cis-Urals. It is pointed out that the latter are represented both by native and derivative stands formed in the place of native coniferous forest, for the most part pine stands. Birch stands, as a rule, have vegetative origin, low density (0.3–0.5 and deposit that does not exceed 130 m3/ha. As a silvicultural measure aimed at derivative birch stands’ productivity increasing, it is offered to create under the canopy preliminary forest crops of Scotch pine. The advantage of such crops is tending of plantations cutting and terms of technic mature wood growing. It has been determined that in investigated regions with low density birch stands on grey forest soil and chernozem, Scotch pine in preliminary forest crops develops surface roots which are branching in different directions from planting sites including in the direction of the brand stems. These roots are terminated among the interplacement mass of this mass of stiffened roots. In other words, on the first step of forest growing, preliminary crops do not experience considerable root competition as concerns birch stand. Based on the research data, high safe keeping of preliminary forest crops during the initial years after planting is proved. However, delay in birch stands harvesting can result in preliminary forest crops increment reduction and, in the long run, their destruction. Thus the mean height of the preliminary pine crops at the age of 11–12 years constitutes only 42–62 % as compared with pine crops of the same age that were formed on the cutover area if agrotechnical tending is systematically carried on in the latter. The positive role of birch stands in the initial 3–4 years after preliminary forest crops of Scotch pine forming has been proven experimentally. Then the birch woody canopy must be removed. Replacement of derivative birch stands for native pine stands by forming preliminary forest crops will make

  19. Interspecific variation in resistance of Asian, European, and North American birches (Betula spp.) to bronze birch borer (Coleoptera: Buprestidae).

    Science.gov (United States)

    Nielsen, David G; Muilenburg, Vanessa L; Herms, Daniel A

    2011-06-01

    Bronze birch borer (Agrilus anxius Gory) is the key pest of birches (Betula spp.) in North America, several of which have been recommended for ornamental landscapes based on anecdotal reports of borer resistance that had not been confirmed experimentally. In a 20-yr common garden experiment initiated in 1979 in Ohio, North American birch species, including paper birch (Betula papyrifera Marshall), 'Whitespire' gray birch (Betula populifolia Marshall), and river birch (Betula nigra L.), were much more resistant to bronze birch borer than species indigenous to Europe and Asia, including European white birch (Betula pendula Roth), downy birch (Betula pubescens Ehrh.), monarch birch (Betula maximowicziana Regel), and Szechuan white birch (Betula szechuanica Jansson). Within 8 yr of planting, every European white, downy, and Szechuan birch had been colonized and killed, although 100% of monarch birch had been colonized and 88% of these plants were killed after nine years. Conversely, 97% of river birch, 76% of paper birch, and 73% Whitespire gray birch were alive 20 yr after planting, and river birch showed no evidence of colonization. This pattern is consistent with biogeographic theory of plant defense: North American birch species that share a coevolutionary history with bronze birch borer were much more resistant than naïve hosts endemic to Europe and Asia, possibly by virtue of evolution of targeted defenses. This information suggests that if bronze birch borer were introduced to Europe or Asia, it could threaten its hosts there on a continental scale. This study also exposed limitations of anecdotal observation as evidence of host plant resistance.

  20. Fast pyrolysis in a novel wire-mesh reactor: decomposition of pine wood and model compounds

    NARCIS (Netherlands)

    Hoekstra, E.; Swaaij, van W.P.M.; Kersten, S.R.A.; Hogendoorn, J.A.

    2012-01-01

    In fast pyrolysis, biomass decomposition processes are followed by vapor phase reactions. Experimental results were obtained in a unique wire-mesh reactor using pine wood, KCl impregnated pine wood and several model compounds (cellulose, xylan, lignin, levoglucosan, glucose). The wire-mesh reactor w

  1. Mechanism of Xylan Pyrolysis by Py-GC/MS

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-rong; LIANG Tao; RU Bin; GUO Xiu-juan

    2013-01-01

    In order to investigate the decomposition behavior of hemicellulose,xylan was chosen as the representative of hemicellulose to study the fast pyrolysis on the combination system of analytical pyrolyzer and gas chromatograph coupled with mass spectrometer(Py-GC/MS).The main condensable products of xylan pyrolysis consisted of acids,aldehydes,and ketones; while gas products contained CO2,CO,CH4 and H2.Acetic acid and furfural were the most abundant products with the highest contents of 20.11% and 20.24% respectively.While furfural and acetic acid were formed competitively with residence time and temperature increases,the distribution of xylan pyrolysis products did not vary with the residence time and temperature,while the total content of several kinds of products changed a lot.According to the analysis of experimental data,a reaction pathway of xylan decomposition was deduced so as to illustrate the formation mechanism of main products.

  2. Laccase catalysed grafting of phenolic onto xylan to improve its applicability in films

    Science.gov (United States)

    Pei, Jicheng; Wang, Bing; Zhang, Fangdong; Li, Zhongyang; Yin, Yunbei; Zhang, Dongxu

    2015-07-01

    Xylan can be tailored for various value-added applications. However, its use in aqueous systems is hampered by its complex structure, and small molecular weight. This research aimed at improving the xylan molecular weight and changing its structure. Laccase-catalysed oxidation of 4-coumaric acid (PCA), ferulic acid (FA), syringaldehyde (SD), and vanillin (VA) onto xylan was grafted to study the changes in its structure, tensile properties, and antibacterial activities. A Fourier transform infrared (FTIR) spectrum analyser was used to observe the changes in functional groups of xylan. The results showed a band at 1635 cm-1 corresponding to the stretching vibration of conjugated carbonyl carboxy hemoglobin and a benzene ring structure were strengthened; the appearance of a new band between 1200 cm-1 and 1270 cm-1 corresponding to alkyl ethers on the aryl C-O stretching vibration was due to the fact that during the grafting process, the number of benzene ring structures increased and covalent connections occurred between phenols and xylan. The reaction mechanism for the laccase-catalysed oxidation of phenol compounds onto xylan was preliminary explored by 13C-NMR. The results showed that PCA-xylan, FA-xylan graft poly onto xylan by Cγ ester bond, SD-xylan graft poly onto xylan by ether bond and an ester bond, and VD-xylan graft poly onto xylan by ether bond. The film strength of xylan derivatives has been significantly increased, especially for the PCA-xylan derivative. The increases in tensile stress at break, tensile strength, tensile yield stress, and Young's modulus were: 24.04%, 31.30%, 55.56%, and 28.21%, respectively. After laccase/phenolics were modified, xylan had a good antibacterial effect to E. coli, Corynebacterium glutamicum, and Bacillus subtilis. The SD-xylan, FA-xylan, and PCA-xylan showed a greater efficacy against E. coli, Corynebacterium glutamicum, and Bacillus subtilis, respectively.

  3. Modiifcation of pine pulp during oxygen deligniifcation by xylan self-assembly%氧脱木素过程中松木浆的木聚糖自组装改性

    Institute of Scientific and Technical Information of China (English)

    周丹丹

    2015-01-01

    自组装是包括大分子在内的不同种目标分子之间相互作用的一种制备功能材料的技术。本文使用的阔叶木木聚糖,分别采用加压热水抽提(HWX)和碱抽提(CAX)从桦木木片和桦木漂白硫酸盐浆中获得。抽提出来的木聚糖使用气相色谱法(GC)、体积排阻色谱法(SEC)和傅立叶变换红外光谱(FTIR)来定性,随后将其加入到松木硫酸盐浆进行氧脱木素的反应器中。木聚糖-纸浆纤维的组装,使用先进的飞行时间次级离子质谱法(ToF-SIMS)和成像技术来表征。  木聚糖-松木浆的组装产物在全无氯漂白和低浓打浆过程中并没有明显的脱除。相对比参照纸浆,改性纤维具有非常好的机械性能。本技术易于应用到制浆造纸工业中,并且为充分利用生物纤维新材料提供了新的可能。%Self-assembly is a technique of preparing functional materials based on targeted intermolecular inter-actions involving different macromolecules. In this work, hardwood xylan was disassembled from wood and birch bleached kraft pulp using pressurized hot water extraction (HWX) and cold alkali extraction (CAX), respectively. The extracted biopolymers were characterized using gas chromatography (GC), size exclusion chromatography (SEC) and fourier transform infrared spectroscopy (FTIR), and subsequently added into an oxygen deligniifcation reactor containing pine kraft pulp. The assembly of xylan-pulp ifber was characterized using advanced time-of-lfight secondary ion mass spectrometry (ToF-SIMS) and imaging. The xylan-pine pulp assembly was not signiifcantly removed during the whole elemental chlorine free bleaching sequence or during low consistency reifning. Modiifed ifbers had superior mechanical properties compared to the reference pulp. Our concept can be easily applied in the pulp and paper industry, and it opens new possibilities for the utilization of fully bio-based ifbers in new

  4. Accumulation of recalcitrant xylan in mushroom-compost is due to a lack of xylan substituent removing enzyme activities of Agaricus bisporus

    NARCIS (Netherlands)

    Jurak, Edita; Patyshakuliyeva, Aleksandrina; Kapsokalyvas, Dimitris; Xing, Lia; van Zandvoort, Marc A M J; de Vries, Ronald P; Gruppen, Harry; Kabel, Mirjam A

    2015-01-01

    The ability of Agaricus bisporus to degrade xylan in wheat straw based compost during mushroom formation is unclear. In this paper, xylan was extracted from the compost with water, 1M and 4M alkali. Over the phases analyzed, the remaining xylan was increasingly substituted with

  5. [Oral allergy syndrome among patients with birch pollinosis in Sapporo].

    Science.gov (United States)

    Yamamoto, Tetsuo; Asakura, Kohji; Shirasaki, Hideaki; Himi, Tetsuo; Ogasawara, Hideki; Narita, Shin-Ichirou; Kataura, Akikatsu

    2004-04-01

    We evaluated the relationships between oral and pharyngeal hypersensitivity to fruits and vegetables (oral allergy syndrome) and birch pollinosis in 2003 in Sapporo. 1. Of 153 patients with birch pollinosis (seasonal nasal or ocular symptom and CAP positive [birch pollen CAP score 2 or more]), 65 patients (42%) have episode of oral allergy syndrome (OAS). And that rate in 2003 was higher than in 1992 and was equal to in 1998. 2. Among birch pollinosis patients, the higher the CAP score of birch pollen, the higher the prevalences of OAS were found to be. 3. Among birch pollinosis patients, female have OAS much more than male. 4. Among birch pollinosis patients in 1998, patients who visited to ENT clinic for medical consultation of birch pollinosis in March and April have OAS much more than patients who visited in May and June.

  6. Christian Birch - den korrupte konferensråd

    DEFF Research Database (Denmark)

    Jensen, Mette Frisk

    2005-01-01

      http://www.sidensaxo.dk/fileadmin/saxo-abstract-uploads/christian_birch_den_korrupte_konferensraad_2005_3.pdf......  http://www.sidensaxo.dk/fileadmin/saxo-abstract-uploads/christian_birch_den_korrupte_konferensraad_2005_3.pdf...

  7. Hydrolysis kinetics of tulip tree xylan in hot compressed water.

    Science.gov (United States)

    Yoon, Junho; Lee, Hun Wook; Sim, Seungjae; Myint, Aye Aye; Park, Hee Jeong; Lee, Youn-Woo

    2016-08-01

    Lignocellulosic biomass, a promising renewable resource, can be converted into numerous valuable chemicals post enzymatic saccharification. However, the efficacy of enzymatic saccharification of lignocellulosic biomass is low; therefore, pretreatment is necessary to improve the efficiency. Here, a kinetic analysis was carried out on xylan hydrolysis, after hot compressed water pretreatment of the lignocellulosic biomass conducted at 180-220°C for 5-30min, and on subsequent xylooligosaccharide hydrolysis. The weight ratio of fast-reacting xylan to slow-reacting xylan was 5.25 in tulip tree. Our kinetic results were applied to three different reaction systems to improve the pretreatment efficiency. We found that semi-continuous reactor is promising. Lower reaction temperatures and shorter space times in semi-continuous reactor are recommended for improving xylan conversion and xylooligosaccharide yield. In the theoretical calculation, 95% of xylooligosaccharide yield and xylan conversion were achieved simultaneously with high selectivity (desired product/undesired product) of 100 or more. Copyright © 2016. Published by Elsevier Ltd.

  8. Utilization of non-merchantable wood in Steppe regions

    Energy Technology Data Exchange (ETDEWEB)

    Dobrovol' skil, E.Ya.

    1979-01-01

    A description, with diagram, is given of the design of a small mobile retort developed in the USSR for pyrolysis of unmerchantable wood in the steppe regions. The type of wood considered is the tree and shrub material in shelterbelts, e.g. Cornus sanguinea, Elaeagnus angustifolia, Ribes aureum, Cotinus coggygria (Rhus continus) and Caragana arborescens. Yields of charcoal, settled tar, alcohols, and volatile acids from each of these species are given in % of oven-dry wood for pyrolysis at 320/sup 0/C for 2 h. Comparative data are given for dry distillation of wood of birch, spruce, and pine (400/sup 0/C, 8 h).

  9. Birch Stands Growth Increase in Western Siberia

    Science.gov (United States)

    Kharuk, Viacheslav I.; Kuzmichev, Valeriy V.; Im, Sergey T.; Ranson, Kenneth J.

    2014-01-01

    Birch (Betula pendula Roth) growth within the Western Siberia forest-steppe was analyzed based on long-term (1897-2006) inventory data (height, diameter at breast height [dbh], and stand volume). Analysis of biometry parameters showed increased growth at the beginning of twenty-first century compared to similar stands (stands age = 40-60 years) at the end of nineteenth century. Mean height, dbh, and stem volume increased from 14 to 20 m, from 16 to 22 cm, and from approx. 63 to approx. 220 cu m/ha, respectively. Significant correlations were found between the stands mean height, dbh, and volume on the one hand, and vegetation period length (r(sub s) = 0.71 to 0.74), atmospheric CO2 concentration (r(sub s) = 0.71 to 0.76), and drought index (Standardized Precipitation-Evapotranspiration Index, r(sub s) = -0.33 to -0.51) on the other hand. The results obtained have revealed apparent climate-induced impacts (e.g. increase of vegetation period length and birch habitat drying due to drought increase) on the stands growth. Along with this, a high correlation of birch biometric parameters and [CO2] in ambient air indicated an effect of CO2 fertilization. Meanwhile, further drought increase may switch birch stand growth into decline and greater mortality as has already been observed within the Trans-Baikal forest-steppe ecotone.

  10. The water regime of silver (Betula pendula Roth) and Karelian (Betula pendula var. carelica) birches under sufficient and limited soil moisture conditions.

    Science.gov (United States)

    Sazonova, T.; Pridacha, V.; Olchev, A.

    2012-04-01

    The sensitivity of the silver (Betula pendula Roth) and Karelian (Betula pendula var. carelica) birches to different soil moisture conditions was investigated using results of field measurements provided in 2008-11 at forest experimental sites of the Forest Research Institute of Karelian Research Center of RAS in Karelia, Russia. Karelian birch is a specific form of the silver birch and it is characterized by structural abnormalities of trunk tissues (thickenings on the trunk, the marble-like pattern and figured wood) that results in considerable reduction of number of xylem vessels and increase of parenchyma cell number (Novitskaya, 2008). For experimental study several three-, five- and seven-year old trees of the silver and Karelian birches were selected. The transpiration rate of the leaves (E) was determined using the portable photosynthesis system Li-6400XTR (Li-Cor, USA). Leaf water potential of photosynthesizing leaves (Ψ) was measured using the pressure chamber. Amount of available water in leaves (WCf), water deficit (WSD) and saturating leaf water content (WCs) were calculated using the following equations: WCf = (Wf -Wd)/ Wd (gwatergdryweight-1), WSD = (Ws - Wf)/(Ws - Wd) (%), WCs= (Ws- Wf) / Wd (gwatergdryweight-1), where Wf and Wd - fresh and dried leaf biomass, Ws - weight of the leaves at saturation. Comparisons of three and five years old birches showed that the differences between WSD and WCs of the Karelian and silver birch increased with tree age. It can be explained that the Karelian birch has increased parenchyma and significant amount of water can be additionally stored there. Comparisons of WSD and WCs of silver birches of both forms show that the differences between forms increase with growth of water deficit in plants. It was observed in both seasonal and daily patterns. The largest differences were indicated at the afternoon and at the end of growing season (from middle of August until September). These results also show that WSD and WCs

  11. Thermoactive cellulase-free xylanase production from alkaliphilic ...

    African Journals Online (AJOL)

    Thermoactive cellulase-free xylanase production from alkaliphilic Bacillus strains ... were obtained by cultivation in birch-wood xylan, but high enzyme production was ... conditions, no cellulolytic activity were detected on the crude extracts.

  12. Obtaining ethanol from hemicelluloses (xylane) of deciduous trees and one year old plants. Final report. Gewinnung von Ethanol aus den Hemicellulosen (Xylanen) von Laubhoelzern und Einjahrespflanzen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Puls, J.; Wiegel, J.

    1985-01-01

    In contrast to yeast, bacteria have a wide substrate spectrum. Certain bacteria can convert xylose into ethanol. Thermo-anaerobic bacterium ethanolicus and its mutants can also hydrolyse oligomeric xylane and produce alcohol. An elegant and simple process to obtain pentose and pentosane from ligno-cellulose is the steam pressure extraction process, in which the hemi-cellulose can be obtained by prewashing after brief steam pressure treatment between 170 and 210degC. By controlling the parameters of temperature and time, the hemicellulose yield can be optimized and the production of sugar decay products can be minimised. The batch fermentation of a polymer beech wood xylane after integrated hydrolysis and sterilisation gave an ethanol concentration of 5.3 g/litre after 94 hours.

  13. Characterization of substituents in xylans from corn cobs and stover

    NARCIS (Netherlands)

    Dongen, van F.E.M.; Eylen, van D.; Kabel, M.A.

    2011-01-01

    Structural knowledge on hemicellulose from corn cobs and stover is helpful to better understand their position within the plant cell wall architecture as well as their enzymatic saccharification. In this research different extracts were prepared with water, 1 M and 4 M alkali. Most of the xylans wer

  14. Quantitative DNA Analyses for Airborne Birch Pollen.

    Directory of Open Access Journals (Sweden)

    Isabell Müller-Germann

    Full Text Available Birch trees produce large amounts of highly allergenic pollen grains that are distributed by wind and impact human health by causing seasonal hay fever, pollen-related asthma, and other allergic diseases. Traditionally, pollen forecasts are based on conventional microscopic counting techniques that are labor-intensive and limited in the reliable identification of species. Molecular biological techniques provide an alternative approach that is less labor-intensive and enables identification of any species by its genetic fingerprint. A particularly promising method is quantitative Real-Time polymerase chain reaction (qPCR, which can be used to determine the number of DNA copies and thus pollen grains in air filter samples. During the birch pollination season in 2010 in Mainz, Germany, we collected air filter samples of fine (<3 μm and coarse air particulate matter. These were analyzed by qPCR using two different primer pairs: one for a single-copy gene (BP8 and the other for a multi-copy gene (ITS. The BP8 gene was better suitable for reliable qPCR results, and the qPCR results obtained for coarse particulate matter were well correlated with the birch pollen forecasting results of the regional air quality model COSMO-ART. As expected due to the size of birch pollen grains (~23 μm, the concentration of DNA in fine particulate matter was lower than in the coarse particle fraction. For the ITS region the factor was 64, while for the single-copy gene BP8 only 51. The possible presence of so-called sub-pollen particles in the fine particle fraction is, however, interesting even in low concentrations. These particles are known to be highly allergenic, reach deep into airways and cause often severe health problems. In conclusion, the results of this exploratory study open up the possibility of predicting and quantifying the pollen concentration in the atmosphere more precisely in the future.

  15. Quantitative DNA Analyses for Airborne Birch Pollen.

    Science.gov (United States)

    Müller-Germann, Isabell; Vogel, Bernhard; Vogel, Heike; Pauling, Andreas; Fröhlich-Nowoisky, Janine; Pöschl, Ulrich; Després, Viviane R

    2015-01-01

    Birch trees produce large amounts of highly allergenic pollen grains that are distributed by wind and impact human health by causing seasonal hay fever, pollen-related asthma, and other allergic diseases. Traditionally, pollen forecasts are based on conventional microscopic counting techniques that are labor-intensive and limited in the reliable identification of species. Molecular biological techniques provide an alternative approach that is less labor-intensive and enables identification of any species by its genetic fingerprint. A particularly promising method is quantitative Real-Time polymerase chain reaction (qPCR), which can be used to determine the number of DNA copies and thus pollen grains in air filter samples. During the birch pollination season in 2010 in Mainz, Germany, we collected air filter samples of fine (<3 μm) and coarse air particulate matter. These were analyzed by qPCR using two different primer pairs: one for a single-copy gene (BP8) and the other for a multi-copy gene (ITS). The BP8 gene was better suitable for reliable qPCR results, and the qPCR results obtained for coarse particulate matter were well correlated with the birch pollen forecasting results of the regional air quality model COSMO-ART. As expected due to the size of birch pollen grains (~23 μm), the concentration of DNA in fine particulate matter was lower than in the coarse particle fraction. For the ITS region the factor was 64, while for the single-copy gene BP8 only 51. The possible presence of so-called sub-pollen particles in the fine particle fraction is, however, interesting even in low concentrations. These particles are known to be highly allergenic, reach deep into airways and cause often severe health problems. In conclusion, the results of this exploratory study open up the possibility of predicting and quantifying the pollen concentration in the atmosphere more precisely in the future.

  16. The Banyan and the Birch Tree

    DEFF Research Database (Denmark)

    Lorenzen, Mark; Taeube, Florian A.

    Theoretical and empirical research on entrepreneurial networks is largely outcome-oriented and little integrated with family firm research. In this paper, we draw on social network and entrepreneurship literatures in order to investigate how family businesses build and make use of a variety of em...... compared to the plain structure of a birch tree describing Hollywood, where embedded ties can be different from familial ties....

  17. Antioxidant and antimicrobial activity of Maillard reaction products from xylan with chitosan/chitooligomer/glucosamine hydrochloride/taurine model systems.

    Science.gov (United States)

    Wu, Shuping; Hu, Jiao; Wei, Liuting; Du, Yumin; Shi, Xiaowen; Zhang, Lina

    2014-04-01

    The structure, UV absorbance, browning intensity, fluorescence changes, antioxidant activity and antimicrobial assessment of Maillard reaction products (MRPs) derived from xylan with chitosan, chitooligomer, glucosamine hydrochloride and taurine model systems were evaluated. The results revealed that all MRPs had similar infrared spectra and molecular structures. MRPs from different model systems on the UV absorbance at 294 nm after heated 90 min and browning intensity at 420 nm showed the similar law: xylan-taurine > xylan-glucosamine hydrochloride > xylan-chitooligomer > xylan-chitosan, and the order of DPPH scavenging activity of MRPs was as follows: xylan-chitosan > xylan-chitooligomer > xylan-glucosamine hydrochloride > xylan-taurine, which revealed that the properties of MRPs were closely related to molecular weight of model systems. Moreover, the highest radical scavenging activity of MRPs from xylan with chitosan/chitooligomer/glucosamine hydrochloride/taurine model systems was 65.9%, 63.7%, 46.4% and 42.5%, respectively.

  18. Birch pollen allergy: molecular characterization and hypoallergenic products

    NARCIS (Netherlands)

    Schenk, M.F.

    2008-01-01

    Allergic diseases, such as hay fever and food allergy, affect a substantial part of the population in westernized countries. Pollen of the European white birch (Betula pendula) is a considerable cause of hay fever (seasonal allergic rhinitis) in northern and central Europe. The major birch pollen al

  19. Birch pollen allergy: molecular characterization and hypoallergenic products

    NARCIS (Netherlands)

    Schenk, M.F.

    2008-01-01

    Allergic diseases, such as hay fever and food allergy, affect a substantial part of the population in westernized countries. Pollen of the European white birch (Betula pendula) is a considerable cause of hay fever (seasonal allergic rhinitis) in northern and central Europe. The major birch pollen al

  20. Wood Smoke

    Science.gov (United States)

    Smoke is made up of a complex mixture of gases and fine, microscopic particles produced when wood and other organic matter burn. The biggest health threat from wood smoke comes from fine particles (also called particulate matter).

  1. Mechanisms of particle-induced pulmonary inflammation in a mouse model: exposure to wood dust.

    Science.gov (United States)

    Määttä, Juha; Lehto, Maili; Leino, Marina; Tillander, Sari; Haapakoski, Rita; Majuri, Marja-Leena; Wolff, Henrik; Rautio, Sari; Welling, Irma; Husgafvel-Pursiainen, Kirsti; Savolainen, Kai; Alenius, Harri

    2006-09-01

    Repeated airway exposure to wood dust has long been known to cause adverse respiratory effects such as asthma and chronic bronchitis and impairment of lung function. However, the mechanisms underlying the inflammatory responses of the airways after wood dust exposure are poorly known. We used a mouse model to elucidate the mechanisms of particle-induced inflammatory responses to fine wood dust particles. BALB/c mice were exposed to intranasally administered fine (more than 99% of the particles had a particle size of dusts twice a week for 3 weeks. PBS, LPS, and titanium dioxide were used as controls. Intranasal instillation of birch or oak dusts elicited influx of inflammatory cells to the lungs in mice. Enhancement of lymphocytes and neutrophils was seen after oak dust exposure, whereas eosinophil infiltration was higher after birch dust exposure. Infiltration of inflammatory cells was associated with an increase in the mRNA levels of several cytokines, chemokines, and chemokine receptors in lung tissue. Oak dust appeared to be a more potent inducer of these inflammatory mediators than birch dust. The results from our in vivo mouse model show that repeated airway exposure to wood dust can elicit lung inflammation, which is accompanied by induction of several proinflammatory cytokines and chemokines. Oak and birch dusts exhibited quantitative and qualitative differences in the elicitation of pulmonary inflammation, suggesting that the inflammatory responses induced by the wood species may rise via different cellular mechanisms.

  2. Delignification outperforms alkaline extraction for xylan fingerprinting of oil palm empty fruit bunch.

    Science.gov (United States)

    Murciano Martínez, Patricia; Kabel, Mirjam A; Gruppen, Harry

    2016-11-20

    Enzyme hydrolysed (hemi-)celluloses from oil palm empty fruit bunches (EFBs) are a source for production of bio-fuels or chemicals. In this study, after either peracetic acid delignification or alkaline extraction, EFB hemicellulose structures were described, aided by xylanase hydrolysis. Delignification of EFB facilitated the hydrolysis of EFB-xylan by a pure endo-β-1,4-xylanase. Up to 91% (w/w) of the non-extracted xylan in the delignified EFB was hydrolysed compared to less than 4% (w/w) of that in untreated EFB. Alkaline extraction of EFB, without prior delignification, yielded only 50% of the xylan. The xylan obtained was hydrolysed only for 40% by the endo-xylanase used. Hence, delignification alone outperformed alkaline extraction as pretreatment for enzymatic fingerprinting of EFB xylans. From the analysis of the oligosaccharide-fingerprint of the delignified endo-xylanase hydrolysed EFB xylan, the structure was proposed as acetylated 4-O-methylglucuronoarabinoxylan.

  3. BIRCH: A user-oriented, locally-customizable, bioinformatics system

    Directory of Open Access Journals (Sweden)

    Fristensky Brian

    2007-02-01

    Full Text Available Abstract Background Molecular biologists need sophisticated analytical tools which often demand extensive computational resources. While finding, installing, and using these tools can be challenging, pipelining data from one program to the next is particularly awkward, especially when using web-based programs. At the same time, system administrators tasked with maintaining these tools do not always appreciate the needs of research biologists. Results BIRCH (Biological Research Computing Hierarchy is an organizational framework for delivering bioinformatics resources to a user group, scaling from a single lab to a large institution. The BIRCH core distribution includes many popular bioinformatics programs, unified within the GDE (Genetic Data Environment graphic interface. Of equal importance, BIRCH provides the system administrator with tools that simplify the job of managing a multiuser bioinformatics system across different platforms and operating systems. These include tools for integrating locally-installed programs and databases into BIRCH, and for customizing the local BIRCH system to meet the needs of the user base. BIRCH can also act as a front end to provide a unified view of already-existing collections of bioinformatics software. Documentation for the BIRCH and locally-added programs is merged in a hierarchical set of web pages. In addition to manual pages for individual programs, BIRCH tutorials employ step by step examples, with screen shots and sample files, to illustrate both the important theoretical and practical considerations behind complex analytical tasks. Conclusion BIRCH provides a versatile organizational framework for managing software and databases, and making these accessible to a user base. Because of its network-centric design, BIRCH makes it possible for any user to do any task from anywhere.

  4. Establishing an Alaskan birch syrup industry: Birch Syrup—It’s the Un-maple!TM

    Science.gov (United States)

    Marlene. Cameron

    2001-01-01

    Ten years ago a small group of Alaskans began commercial production of birch syrup from the sap of the paper birch, Betula papyrifera, and established an industry that is expanding in response to demand and has the potential to make a significant contribution to Alaska's economy. There are still many problems to be solved; research and...

  5. 75 FR 51987 - Birch Power Company and Sorenson Engineering; Birch Power Company and Sorenson Leasing L.L.C...

    Science.gov (United States)

    2010-08-24

    ... Sorenson Leasing L.L.C.; Notice of Application for Transfer of License, and Soliciting Comments and Motions... (transferors) and Birch Power Company and Sorenson Leasing, L.L.C. (transferees) filed an application for..., Birch Power Company, Sorenson Engineering, and Sorenson Leasing L.L.C., 5203 South 11th East,...

  6. Specific tracking of xylan using fluorescent-tagged carbohydrate-binding module 15 as molecular probe

    OpenAIRE

    Khatri, Vinay; Hébert-Ouellet, Yannick; Meddeb-Mouelhi, Fatma; Beauregard,Marc

    2016-01-01

    Background Xylan has been identified as a physical barrier which limits cellulose accessibility by covering the outer surface of fibers and interfibrillar space. Therefore, tracking xylan is a prerequisite for understanding and optimizing lignocellulosic biomass processes. Results In this study, we developed a novel xylan tracking approach using a two-domain probe called OC15 which consists of a fusion of Cellvibrio japonicus carbohydrate-binding domain 15 with the fluorescent protein mOrange...

  7. 木聚糖制备方法研究进展%Preparation and Application of Xylan

    Institute of Scientific and Technical Information of China (English)

    孙毅; 韩春超

    2014-01-01

    低聚木糖目前是一种重要的功能性食品。本文综述了从稻壳中提取木聚糖、超声波法提取玉米芯木聚糖以及棉籽壳提取木聚糖的制备方法和得率计算。%This paper has reviewed the progress of xylan and the preparation.Xylan preparation by extract from the rice husk xylan, ultrasonic extraction of corncob xylan and xylan extraction of Cotton Seed Hull material . The application of xylan was also reviewed.

  8. The influence of hybridization on epidermal properties of birch species and the consequences for palaeoclimatic interpretations

    NARCIS (Netherlands)

    Wagner, F.; Kürschner, W.M.; Neuvonen, S.; Visscher, H.

    2000-01-01

    The Fennoscandian birch population primarily consists of Betula nana, B. pendula and B. pubescens ssp. czerepanovii, the Mountain birch. Frequent hybridization between the Mountain birch and B. nana generates a wide range of genotypic and phenotypic plasticity in the subarctic birch zone of Fennosca

  9. Molecular Ice Nucleation Activity of Birch Pollen

    Science.gov (United States)

    Felgitsch, Laura; Bichler, Magdalena; Häusler, Thomas; Weiss, Victor U.; Marchetti-Deschmann, Martina; Allmaier, Günter; Grothe, Hinrich

    2015-04-01

    Heterogeneous ice nucleation plays a major part in ecosystem and climate. Due to the triggering of ice cloud formation it influences the radiation balance of the earth, but also on the ground it can be found to be important in many processes of nature. So far the process of heterogeneous ice nucleation is not fully understood and many questions remain to be answered. Biological ice nucleation is hereby from great interest, because it shows the highest freezing temperatures. Several bacteria and fungi act as ice nuclei. A famous example is Pseudomonas syringae, a bacterium in commercial use (Snomax®), which increases the freezing from homogeneous freezing temperatures of approx. -40° C (for small volumes as in cloud droplets) to temperatures up to -2° C. In 2001 it was found that birch pollen can trigger ice nucleation (Diehl et al. 2001; Diehl et al. 2002). For a long time it was believed that this is due to macroscopic features of the pollen surface. Recent findings of Bernhard Pummer (2012) show a different picture. The ice nuclei are not attached on the pollen surface directly, but on surface material which can be easily washed off. This shows that not only the surface morphology, but also specific molecules or molecular structures are responsible for the ice nucleation activity of birch pollen. With various analytic methods we work on elucidating the structure of these molecules as well as the mechanism with which they trigger ice nucleation. To solve this we use various instrumental analytic techniques like Nuclear Magnetic Resonance spectroscopy (NMR), Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS), and Gas-phase Electrophoretic Mobility Molecular Analysis (GEMMA). Also standard techniques like various chromatographic separation techniques and solvent extraction are in use. We state here that this feature might be due to the aggregation of small molecules, with agglomerates showing a specific surface structure. Our results

  10. Effects of heat treatment of wood on hydroxylapatite type mineral precipitation and biomechanical properties in vitro.

    Science.gov (United States)

    Rekola, J; Lassila, L V J; Hirvonen, J; Lahdenperä, M; Grenman, R; Aho, A J; Vallittu, P K

    2010-08-01

    Wood is a natural fiber reinforced composite. It structurally resembles bone tissue to some extent. Specially heat-treated birch wood has been used as a model material for further development of synthetic fiber reinforced composites (FRC) for medical and dental use. In previous studies it has been shown, that heat treatment has a positive effect on the osteoconductivity of an implanted wood. In this study the effects of two different heat treatment temperatures (140 and 200 degrees C) on wood were studied in vitro. Untreated wood was used as a control material. Heat treatment induced biomechanical changes were studied with flexural and compressive tests on dry birch wood as well as on wood after 63 days of simulated body fluid (SBF) immersion. Dimensional changes, SBF sorption and hydroxylapatite type mineral formation were also assessed. The results showed that SBF immersion decreases the biomechanical performance of wood and that the heat treatment diminishes the effect of SBF immersion on biomechanical properties. With scanning electron microscopy and energy dispersive X-ray analysis it was shown that hydroxylapatite type mineral precipitation formed on the 200 degrees C heat-treated wood. An increased weight gain of the same material during SBF immersion supported this finding. The results of this study give more detailed insight of the biologically relevant changes that heat treatment induces in wood material. Furthermore the findings in this study are in line with previous in vivo studies.

  11. Phylogeny, classification and metagenomic bioprospecting of microbial acetyl xylan esterases.

    Science.gov (United States)

    Adesioye, Fiyinfoluwa A; Makhalanyane, Thulani P; Biely, Peter; Cowan, Don A

    2016-11-01

    Acetyl xylan esterases (AcXEs), also termed xylan deacetylases, are broad specificity Carbohydrate-Active Enzymes (CAZymes) that hydrolyse ester bonds to liberate acetic acid from acetylated hemicellulose (typically polymeric xylan and xylooligosaccharides). They belong to eight families within the Carbohydrate Esterase (CE) class of the CAZy database. AcXE classification is largely based on sequence-dependent phylogenetic relationships, supported in some instances with substrate specificity data. However, some sequence-based predictions of AcXE-encoding gene identity have proved to be functionally incorrect. Such ambiguities can lead to mis-assignment of genes and enzymes during sequence data-mining, reinforcing the necessity for the experimental confirmation of the functional properties of putative AcXE-encoding gene products. Although one-third of all characterized CEs within CAZy families 1-7 and 16 are AcXEs, there is a need to expand the sequence database in order to strengthen the link between AcXE gene sequence and specificity. Currently, most AcXEs are derived from a limited range of (mostly microbial) sources and have been identified via culture-based bioprospecting methods, restricting current knowledge of AcXEs to data from relatively few microbial species. More recently, the successful identification of AcXEs via genome and metagenome mining has emphasised the huge potential of culture-independent bioprospecting strategies. We note, however, that the functional metagenomics approach is still hampered by screening bottlenecks. The most relevant recent reviews of AcXEs have focused primarily on the biochemical and functional properties of these enzymes. In this review, we focus on AcXE phylogeny, classification and the future of metagenomic bioprospecting for novel AcXEs.

  12. Diversity in Production of Xylan-Degrading Enzymes Among Species Belonging to the Trichoderma Section Longibrachiatum

    NARCIS (Netherlands)

    Toth, K.; Gool, van M.P.; Schols, H.A.; Samuels, G.J.; Gruppen, H.; Szakacs, G.

    2013-01-01

    Xylan is an important part of plant biomass and represents a renewable raw material for biorefineries. Contrary to cellulose, the structure of hemicellulose is quite complex. Therefore, the biodegradation of xylan needs the cooperation of many enzymes. For industrial production of xylanase

  13. Gorse (Ulex europaeus) as a possible source of xylans by hydrothermal treatment

    NARCIS (Netherlands)

    Ligero, P.; Vega, de A.; Kolk, van der J.C.; Dam, van J.E.G.

    2011-01-01

    Autocatalytic hydrothermal process conditions were used to study Ulex europæus (Gorse) as a source of xylan compounds. The aim was to study the possibilities for using this unutilised biomass material to produce xylans. Ulex is an evergreen shrub that grows in the northwest of Spain and has no econo

  14. Methods for estimating production and utilization of paper birch saplings

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Development of technique to estimate browse production and utilization. Developed a set of methods for estimating annual production and utilization of paper birch...

  15. Development of yellow birch nursery stock not affected by transplanting

    Science.gov (United States)

    William B. Leak

    1959-01-01

    In nursery seedbeds, severe root competition soon develops among seedlings of yellow birch (Betula alleghaniensis). This is due to the characteristic root system of the species - wide-spreading lateral growth with little downward penetration (fig. 1).

  16. Food allergy to apple and specific immunotherapy with birch pollen

    DEFF Research Database (Denmark)

    Hansen, Kirsten Skamstrup; Khinchi, Marianne Søndergaard; Skov, Per Stahl

    2004-01-01

    Conflicting results concerning the effect of specific pollen immunotherapy (SIT) on allergy to plant foods have been reported. The aim of this study was to investigate the effect of SIT using a birch pollen extract on food allergy with focus on allergy to apple. Seventy-four birch pollen......-allergic patients were included in a double-blind, double-dummy, and placebo-controlled comparison of sublingual-swallow (SLIT) and subcutaneous (SCIT) administration of a birch pollen extract. Sixty-nine percent of these patients reported allergy to apple. The clinical reactivity to apple was evaluated by open....... Therefore, oral allergy syndrome (OAS) to apple should not be considered as a main criterion for selecting patients for birch pollen immunotherapy at present....

  17. Impact of Wood Species, Dimensions and Drying Temperature on Sorption Behaviour of Wood

    Directory of Open Access Journals (Sweden)

    Darius Albrektas

    2015-04-01

    Full Text Available This research paper examines the interdependence between wood sorption properties and its dimensions, species and drying temperature. The research was carried out on specimens of six species of wood (oak, ash, aspen, birch, spruce and pine which had different dimensions and were dried at temperatures ranging between 30 and 90 °C. Subsequently specimens underwent the moistening and air drying process, and the following parameters were recorded: moistening and drying rate, moisture content distribution, steady moisture content and sorption hysteresis. It was established that sorption hysteresis was most affected by the cross section dimensions of the specimen. It was determined that, when the thickness of wood specimens increases from 7 to 30 mm, sorption hysteresis grows up to 8 times. The steady moisture content depends on the density, measurements and drying temperature of the specimen.

  18. Spatial and temporal variability of xylan distribution in differentiating secondary xylem of hybrid aspen.

    Science.gov (United States)

    Kim, Jong Sik; Sandquist, David; Sundberg, Björn; Daniel, Geoffrey

    2012-06-01

    Xylans occupy approximately one-third of the cell wall components in hardwoods and their chemical structures are well understood. However, the microdistribution of xylans (O-acetyl-4-O-methylglucuronoxylans, AcGXs) in the cell wall and their correlation with functional properties of cells in hardwood xylem is poorly understood. We demonstrate here the spatial and temporal distribution of xylans in secondary xylem cells of hybrid aspen using immunolocalization with LM10 and LM11 antibodies. Xylan labeling was detected earliest in fibers at the cell corner of the S₁ layer, and then later in vessels and ray cells respectively. Fibers showed a heterogeneous labeling pattern in the mature cell wall with stronger labeling of low substituted xylans (lsAcGXs) in the outer than inner cell wall. In contrast, vessels showed uniform labeling in the mature cell wall with stronger labeling of lsAcGXs than fibers. Xylan labeling in ray cells was detected much later than that in fibers and vessels, but was also detected at the beginning of secondary cell wall formation as in fibers and vessels with uniform labeling in the cell wall regardless of developmental stage. Interestingly, pit membranes including fiber-, vessel- and ray-vessel pits showed strong labeling of highly substituted xylans (hsAcGXs) during differentiation, although this labeling gradually disappeared during pit maturation. Together our observations indicate that there are temporal and spatial variations of xylan deposition and chemical structure of xylans between cells in aspen xylem. Differences in xylan localization between aspen (hardwood) and cedar (softwood) are also discussed.

  19. Asymptomatic skin sensitization to birch predicts later development of birch pollen allergy in adults

    DEFF Research Database (Denmark)

    Bødtger, Uffe; Poulsen, Lars K; Malling, Hans-Jørgen

    2003-01-01

    BACKGROUND: The skin prick test is the allergologic test of choice, but asymptomatic skin sensitization to aeroallergens is common. However, no data in the literature describe the clinical phenotype of asymptomatic sensitized adults. OBJECTIVE: The purposes of this investigation were to provide...... provocation test result was 100% negatively predictive. Nasal provocation testing possessed no additional prognostic information. No changes in clinical phenotype were seen in nonatopic or birch-allergic subjects. CONCLUSION: Asymptomatic skin sensitization is a risk factor for later allergy development....... At risk is any subject with target organ sensitivity, an elevated specific IgE level, and/or a skin prick test weal diameter of >4 mm....

  20. Elevated air humidity affects hydraulic traits and tree size but not biomass allocation in young silver birches (Betula pendula

    Directory of Open Access Journals (Sweden)

    Arne eSellin

    2015-10-01

    Full Text Available As changes in air temperature, precipitation, and air humidity are expected in the coming decades, studies on the impact of these environmental shifts on plant growth and functioning are of major importance. Greatly understudied aspects of climate change include consequences of increasing air humidity on forest ecosystems, predicted for high latitudes. The main objective of this study was to find a link between hydraulic acclimation and shifts in trees’ resource allocation in silver birch (Betula pendula Roth in response to elevated air relative humidity (RH. A second question was whether the changes in hydraulic architecture depend on tree size. Two years of application of increased RH decreased the biomass accumulation in birch saplings, but the biomass partitioning among aboveground parts (leaves, branches, and stems remained unaffected. Increased stem Huber values (xylem cross-sectional area to leaf area ratio observed in trees under elevated RH did not entail changes in the ratio of non-photosynthetic to photosynthetic tissues. The reduction of stem-wood density is attributable to diminished mechanical load imposed on the stem, since humidified trees had relatively shorter crowns. Growing under higher RH caused hydraulic conductance of the root system (KR to increase, while KR (expressed per unit leaf area decreased and leaf hydraulic conductance increased with tree size. Saplings of silver birch acclimate to increasing air humidity by adjusting plant morphology (live crown length, slenderness, specific leaf area, and fine-root traits and wood density rather than biomass distribution among aboveground organs. The treatment had a significant effect on several hydraulic properties of the trees, while the shifts were largely associated with changes in tree size but not in biomass allocation.

  1. Engineering of plants with improved properties as biofuels feedstocks by vessel-specific complementation of xylan biosynthesis mutants

    DEFF Research Database (Denmark)

    Petersen, Pia; Lau, Jane; Ebert, Berit

    2012-01-01

    complementation of the irx phenotype than the VND6 promoter. Conclusions: Spatial and temporal deposition of xylan in the secondary cell wall of Arabidopsis can be manipulated by using the promoter regions of vessel-specific genes to express xylan biosynthetic genes. The expression of xylan specifically....... Results: Xylan is the major non-cellulosic polysaccharide in secondary cell walls, and the xylan deficient irregular xylem (irx) mutants irx7, irx8 and irx9 exhibit severe dwarf growth phenotypes. The main reason for the growth phenotype appears to be xylem vessel collapse and the resulting impaired...

  2. Xylan catabolism is improved by blending bioprospecting and metabolic pathway engineering in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lee, Sun-Mi; Jellison, Taylor; Alper, Hal S

    2015-04-01

    Complete utilization of all available carbon sources in lignocellulosic biomass still remains a challenge in engineering Saccharomyces cerevisiae. Even with efficient heterologous xylose catabolic pathways, S. cerevisiae is unable to utilize xylose in lignocellulosic biomass unless xylan is depolymerized to xylose. Here we demonstrate that a blended bioprospecting approach along with pathway engineering and evolutionary engineering can be used to improve xylan catabolism in S. cerevisiae. Specifically, we perform whole genome sequencing-based bioprospecting of a strain with remarkable pentose catabolic potential that we isolated and named Ustilago bevomyces. The heterologous expression of xylan catabolic genes enabled S. cerevisiae to grow on xylan as a single carbon source in minimal medium. A combination of bioprospecting and metabolic pathway evolution demonstrated that the xylan catabolic pathway could be further improved. Ultimately, engineering efforts were able to achieve xylan conversion into ethanol of up to 0.22 g/L on minimal medium compositions with xylan. This pathway provides a novel starting point for improving lignocellulosic conversion by yeast.

  3. Wooded areas

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the management of wooded areas on Neal Smith National Wildlife Refuge (formerly Walnut Creek National Wildlife Refuge) between 1992 and 2009.

  4. Phenolic compounds in ectomycorrhizal interaction of lignin modified silver birch

    Directory of Open Access Journals (Sweden)

    Chiang Vincent L

    2009-09-01

    Full Text Available Abstract Background The monolignol biosynthetic pathway interconnects with the biosynthesis of other secondary phenolic metabolites, such as cinnamic acid derivatives, flavonoids and condensed tannins. The objective of this study is to evaluate whether genetic modification of the monolignol pathway in silver birch (Betula pendula Roth. would alter the metabolism of these phenolic compounds and how such alterations, if exist, would affect the ectomycorrhizal symbiosis. Results Silver birch lines expressing quaking aspen (Populus tremuloides L. caffeate/5-hydroxyferulate O-methyltransferase (PtCOMT under the 35S cauliflower mosaic virus (CaMV promoter showed a reduction in the relative expression of a putative silver birch COMT (BpCOMT gene and, consequently, a decrease in the lignin syringyl/guaiacyl composition ratio. Alterations were also detected in concentrations of certain phenolic compounds. All PtCOMT silver birch lines produced normal ectomycorrhizas with the ectomycorrhizal fungus Paxillus involutus (Batsch: Fr., and the formation of symbiosis enhanced the growth of the transgenic plants. Conclusion The down-regulation of BpCOMT in the 35S-PtCOMT lines caused a reduction in the syringyl/guaiacyl ratio of lignin, but no significant effect was seen in the composition or quantity of phenolic compounds that would have been caused by the expression of PtCOMT under the 35S or UbB1 promoter. Moreover, the detected alterations in the composition of lignin and secondary phenolic compounds had no effect on the interaction between silver birch and P. involutus.

  5. Harvesting wood fuels from mixed stands of hard- and softwood on forest and agricultural land. Final report; Uttag av traedbraensle ur blandbestaand av loev- och barrtraed vaexande paa skogs- och aakermark. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Tord [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Management and Products

    2001-12-01

    The aim was to study the growth of birches (Betula pendula Roth and Betula pubescens Ehrh.) and Norway spruce (Picea abies (L.) Karst.) in mixed stands of birch and spruce, and in pure stands of Norway spruce. Data from nine localities have been analysed. The trials were spread between lat. 56 and 60 deg N. The experiment was established on eight localities in Sweden. Plots in mixed stands of 20-32-year-old birches and Norway spruces were established in 1983-84. Number of stems per hectare, height and diameter of the stems was registered. Then two treatments were made. On a locality all birches in a plot were cut to make pure spruce stands. In another plot 500 birches per hectare were left in the spruce stand for establishing mixed stands. The established stands were then measured. The stands were examined five years later. Stem number, height and diameter was registered. Small corrections in the stands were made eg. birch sprouts were cut and some spruces were cut. In 1996-1998 the stands were examined again. The birch shelter was cut and measured. On one shelter plot per locality 100 birches per hectare was left. The birch shelter was left for making timber production of good quality. The shelter should be cut when the birches are about 60 years old. By the results given in the study there is obvious that MAI for Norway spruce growing for 13-15 years under shelter is lower, 7.2 m{sup 3}/ha/year than for pure spruce stand, 7.9. However the total MAI including birch in the shelter was 11.5 compared with 7.9 m{sup 3}/ha/year in pure spruce stands. Corresponding MAI for biomass in shelter and pure spruce stands was 3.8 and 4.2 ton d.w./ha/year. Total MAI was 6.4 and 4.2 ton/ha/year. A practical implication of the study is that removal of birches when creating mixed stands has too small dimensions for harvesting pulp wood or fuel wood. In the end of the rotation period for mixed stands the birch stems were 16 cm at breast height. These birches could be used as pulp

  6. Birch Creek, Alaska, a wild and scenic river analysis: Preliminary draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Upper Birch Creek, Alaska possessed values which qualify it for inclusion in the National Wild and Scenic Rivers System. The upper Birch Creek and its immediate...

  7. The growth process of natural poplar-birch forests

    Institute of Scientific and Technical Information of China (English)

    LAN Shibo; LUO Xu; LUO Yuliang

    2006-01-01

    With a combination of permanent and temporary sample plots,we investigated the growth conditions of natural poplar-birch forests.The forests were divided into four site classes,using statistical and analytical techniques in a quantitative model,in descending order where site class I was the best.On this basis,the growth of natural poplar-birch forests in the different site classes was studied.The growth processes of height and diameter at breast height were divided into three stages:a fast growing period,a stable growing period and a slow growing period.Results of this study provide a theoretical basis for the directive cultivation of natural poplar-birch forests.

  8. Accumulation of recalcitrant xylan in mushroom-compost is due to a lack of xylan substituent removing enzyme activities of Agaricus bisporus.

    Science.gov (United States)

    Jurak, Edita; Patyshakuliyeva, Aleksandrina; Kapsokalyvas, Dimitris; Xing, Lia; van Zandvoort, Marc A M J; de Vries, Ronald P; Gruppen, Harry; Kabel, Mirjam A

    2015-11-05

    The ability of Agaricus bisporus to degrade xylan in wheat straw based compost during mushroom formation is unclear. In this paper, xylan was extracted from the compost with water, 1M and 4M alkali. Over the phases analyzed, the remaining xylan was increasingly substituted with (4-O-methyl-)glucuronic acid and arabinosyl residues, both one and two arabinosyl residues per xylosyl residue remained. In the 1M and 4M KOH soluble solids of spent compost, 33 and 49 out of 100 xylosyl residues, respectively, were substituted. The accumulation of glucuronic acid substituents matched with the analysis that the two A. bisporus genes encoding for α-glucuronidase activity (both GH115) were not expressed in the A. bisporus mycelium in the compost during fruiting. Also, in a maximum likelihood tree it was shown that it is not likely that A. bisporus possesses genes encoding for the activity to remove arabinose from xylosyl residues having two arabinosyl residues.

  9. Folding of xylan onto cellulose fibrils in plant cell walls revealed by solid-state NMR

    Science.gov (United States)

    Simmons, Thomas J.; Mortimer, Jenny C.; Bernardinelli, Oigres D.; Pöppler, Ann-Christin; Brown, Steven P.; Deazevedo, Eduardo R.; Dupree, Ray; Dupree, Paul

    2016-12-01

    Exploitation of plant lignocellulosic biomass is hampered by our ignorance of the molecular basis for its properties such as strength and digestibility. Xylan, the most prevalent non-cellulosic polysaccharide, binds to cellulose microfibrils. The nature of this interaction remains unclear, despite its importance. Here we show that the majority of xylan, which forms a threefold helical screw in solution, flattens into a twofold helical screw ribbon to bind intimately to cellulose microfibrils in the cell wall. 13C solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, supported by in silico predictions of chemical shifts, shows both two- and threefold screw xylan conformations are present in fresh Arabidopsis stems. The twofold screw xylan is spatially close to cellulose, and has similar rigidity to the cellulose microfibrils, but reverts to the threefold screw conformation in the cellulose-deficient irx3 mutant. The discovery that induced polysaccharide conformation underlies cell wall assembly provides new principles to understand biomass properties.

  10. Structural Investigation of Cell Wall Xylan Polysaccharides from the Leaves of Algerian Argania spinosa.

    Science.gov (United States)

    Hachem, Kadda; Faugeron, Céline; Kaid-Harche, Meriem; Gloaguen, Vincent

    2016-11-21

    Xylan-type polysaccharides were isolated from the leaves of Argania spinosa (L.) Skeels collected in the Tindouf area (southwestern Algeria). Xylan fractions were obtained by sequential alkaline extractions and purified on Sepharose CL-4B. The xylan structure was investigated by enzymatic hydrolysis with an endo-β(1→4)-xylanase followed by chromatography of the resulting fragments on Biogel P2, characterization by sugar analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS ). The results show that the A. spinosa xylan is composed of a β-(1→4)-d-xylopyranose backbone substituted with 4-O-methyl-d-glucuronic acid and L-arabinose residues.

  11. Isolation and characterization of xylans from seed pericarp of Argania spinosa fruit.

    Science.gov (United States)

    Habibi, Youssef; Vignon, Michel R

    2005-05-23

    Hemicellulose-type polysaccharides were isolated from the pericarp of seeds of Argania spinosa (L.) Skeels fruit by sequential alkaline extractions and fractionated by precipitation. Water soluble and water insoluble fractions were obtained, purified and characterized by sugar analysis and 1H and 13C NMR spectroscopy. The water soluble fractions were assumed to be (4-O-methyl-D-glucurono)-D-xylans, with 4-O-methyl-D-glucopyranosyluronic acid groups linked to C-2 of a (1-->4)-beta-D-xylan. The 1H NMR spectrum showed that the water soluble xylans have, on average, one non-reducing terminal residue of 4-O-methyl-D-glucuronic acid for every seven xylose units. The water insoluble fractions consisted of a neutral xylan with linear (1-->4)-beta-D-xylopyranosyl units.

  12. Structural Investigation of Cell Wall Xylan Polysaccharides from the Leaves of Algerian Argania spinosa

    Directory of Open Access Journals (Sweden)

    Kadda Hachem

    2016-11-01

    Full Text Available Xylan-type polysaccharides were isolated from the leaves of Argania spinosa (L. Skeels collected in the Tindouf area (southwestern Algeria. Xylan fractions were obtained by sequential alkaline extractions and purified on Sepharose CL-4B. The xylan structure was investigated by enzymatic hydrolysis with an endo-β(1→4-xylanase followed by chromatography of the resulting fragments on Biogel P2, characterization by sugar analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS . The results show that the A. spinosa xylan is composed of a β-(1→4-d-xylopyranose backbone substituted with 4-O-methyl-d-glucuronic acid and L-arabinose residues.

  13. Impact of the fouling mechanism on enzymatic depolymerization of xylan in different configurations of membrane reactors

    DEFF Research Database (Denmark)

    Mohd Sueb, Mohd Shafiq Bin; Luo, Jianquan; Meyer, Anne S.

    2017-01-01

    ) and the simultaneous reaction-filtration with both enzymes, respectively. This study thus confirmed that the reactor configuration has a crucial impact on the performance of both the reaction and the separation process of xylose during enzymatic xylan degradation, and that the type of fouling mechanism varies......In order to maximize enzymatic xylan depolymerization while simultaneously purifying the resulting monosaccharide (xylose), different ultrafiltration (UF) membrane reactor configurations were evaluated. Initial results showed that the two hydrolytic enzymes required for complete depolymerization...... of xylan, endo-1,4-β-xylanase and β-xylosidase, promoted different types of fouling, which had a direct impact on the extent of xylan hydrolysis achieved during reaction. Endo-1,4-β-xylanase generated DP 1-6 xylo-oligomers. These products contributed to partial pore blocking of the 1 kDa polysulfone...

  14. Study on the Hydrolysis Kinetics of Xylan on Different Acid Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byeong-Il; Lee, Jae-Won [Chonnam National University, Gwangju (Korea, Republic of)

    2014-04-15

    In this study, we investigated kinetic model for the acid-catalyzed xylan hydrolysis at temperature 120-150 .deg. C. Also, we analyzed the kinetic parameters for xylose production and furfural decomposition. The hydrolysis of xylan and the degradation of xylose were promoted by high reaction temperature and acid concentration. The optimal hydrolysis condition for the highest reaction rate constants (k{sub 1}) was different depending on the acid catalysts. Among sulfuric, oxalic and maleic acid, the xylan reaction rate constants (k{sub 1}) to xylose had the highest value of 0.0241 min{sup -1} when 100 mM sulfuric acid was used at 120 .deg. C. However, sulfuric acid induced more xylose degradation compared to oxalic and maleic acid hydrolysis. The activation energy for xylan degradation was the highest when sulfuric acid was used.

  15. Evaluation of the retail market potential for locally produced paper birch lumber in Alaska.

    Science.gov (United States)

    David L. Nicholls

    2002-01-01

    An evaluation of the retail market potential for random-width paper birch ( Betula papyrifera Marsh.) lumber in Alaska was conducted. Information from lumber manufacturers and retail managers was used to identify current barriers to customer acceptance of locally produced paper birch lumber. Major retail markets and paper birch producing regions throughout Alaska were...

  16. The effect of heat treatment of wood on osteoconductivity.

    Science.gov (United States)

    Rekola, J; Aho, A J; Gunn, J; Matinlinna, J; Hirvonen, J; Viitaniemi, P; Vallittu, P K

    2009-06-01

    Wood is a natural porous fibre composite, which has some structural similarities to bone. Recently, it has been used as a modelling material in developing synthetic fibre-reinforced composite to be used as load-bearing non-metallic artificial bone material. In this study, the behaviour of wood implanted into bone was studied in vivo in the femur bone of the rabbit. Wood was pre-treated by heat, which altered its chemical composition and structure, as well as the biomechanical properties. In the heat treatment, wood's dimensional stability is enhanced, equilibrium moisture content reduces and the biological durability increases. Cone-shaped implants were manufactured from heat-treated (at 200 and 140 degrees C) birch wood (Betula pubescens) and from untreated birch. A total of 62 implants were placed in the distal femur of 50 white New Zealand rabbits. The behaviour of the implants was studied at 4, 8 and 20 weeks with histological and histometrical analysis. Osteoconductive contact line and the presence of fibrous tissue and foreign body reaction were determined. The amount of fibrous tissue diminished with time, and the absence of foreign body reaction was found to be in correlation to the amount of heat treatment. Histologically found contact between the implant and the host bone at the interface was significantly more abundant in the 200 degrees C group (avg. 12.8%) vs. the 140 degrees C (avg. 2.7%) and the untreated groups (avg. 0.6%). It was observed that the heat treatment significantly modified the biological behaviour of the implanted wood. The changes of the wood by heat treatment showed a positive outcome concerning osteoconductivity of the material.

  17. Changes in structural and chemical components of wood delignified by fungi

    Energy Technology Data Exchange (ETDEWEB)

    Blanchette, R.A.; Otjen, L.; Effland, M.J.; Eslyn, W.E.

    1985-01-01

    Cerrena unicolor, Ganoderma applanatum, Ischnoderma resinosum and Poria medulla-panis were associated with birch (Betula papyrifera) wood that had been selectively delignified in the forest. Preferential lignin degradation was not uniformly distributed throughout the decayed wood. A typical white rot causing a simultaneous removal of all cell wall components was also present. In the delignified wood, 95 to 98% of the lignin was removed as well as substantial amounts of hemicelluloses. Scanning and transmission electron microscopy were used to identify the micromorphological and ultrastructural changes that occurred in the cells during degradation. In delignified areas the compound middle lamella was extensively degraded causing a defibration of cells. The secondary wall, especially the S2 layer, remained relatively unaltered. In simultaneously white-rotted wood all cell wall layers were progressively removed from the lumen toward the middle lamella causing erosion troughs or holes to form. Large voids filled with fungal mycelia resulted from a coalition of degraded areas. Birch wood decayed in laboratory soil-block tests was also intermittently delignified, selective delignification, sparsely distributed throughout the wood, and a simultaneous rot resulting in the removal of all cell wall components were evident. SEM appears to be an appropriate technique for examining selectively delignified decayed wood. 30 references.

  18. Fluctuation of birch (Betula L. pollen seasons in Poland

    Directory of Open Access Journals (Sweden)

    Małgorzata Puc

    2015-12-01

    Full Text Available Birch pollen grains are one of the most important groups of atmospheric biological particles that induce allergic processes. The fluctuation pattern of birch pollen seasons in selected cities of Poland is presented. Measurements were performed by the volumetric method (Burkard and Lanzoni 2000 pollen samplers. The distributions of the data were not normal (Shapiro–Wilk test and statistical error risk was estimated at a significance level of α = 0.05. Pollen season was defined as the period in which 95% of the annual total catch occurred. The linear trend for the selected features of the pollen season, skewness, kurtosis and coefficient of variation (V% were also analyzed. During the 12–14 years of study, the beginnings of birch pollen seasons were observed 7–14 days earlier, the ends were noted 5–10 days earlier, and the days with maximum values occurred 7–14 days earlier compared to the long-term data. The left-skewed distribution of the pollen season starts in most sampling sites confirms the short-lasting occurrence of pollen in the air. The threat of birch pollen allergens was high during the pollen seasons. If vegetation is highly diverse, flowering and pollen release are extended in time, spread over different weeks and occur at different times of the day. Flowering time and pollen release are affected by insolation, convection currents, wind, and turbulence. Therefore, pollen seasons are characterized by great inter-annual variability.

  19. Expression of bgt gene in transgenic birch (Betula platyphylla Suk.)

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... dispar was verified in feeding bioassays with the insects. ... After the hybridization of the bgt probe, membranes were stripped twice for 15 min ... Southern blot analysis of transgenic birch plant DNA digested with PstI. Lane 1 ...

  20. Large-Scale Variations in Lumber Value Recovery of Yellow Birch and Sugar Maple in Quebec, Canada.

    Directory of Open Access Journals (Sweden)

    Mariana Hassegawa

    Full Text Available Silvicultural restoration measures have been implemented in the northern hardwoods forests of southern Quebec, Canada, but their financial applicability is often hampered by the depleted state of the resource. To help identify sites most suited for the production of high quality timber, where the potential return on silvicultural investments should be the highest, this study assessed the impact of stand and site characteristics on timber quality in sugar maple (Acer saccharum Marsh. and yellow birch (Betula alleghaniensis Britt.. For this purpose, lumber value recovery (LVR, an estimate of the summed value of boards contained in a unit volume of round wood, was used as an indicator of timber quality. Predictions of LVR were made for yellow birch and sugar maple trees contained in a network of more than 22000 temporary sample plots across the Province. Next, stand-level variables were selected and models to predict LVR were built using the boosted regression trees method. Finally, the occurrence of spatial clusters was verified by a hotspot analysis. Results showed that in both species LVR was positively correlated with the stand age and structural diversity index, and negatively correlated with the number of merchantable stems. Yellow birch had higher LVR in areas with shallower soils, whereas sugar maple had higher LVR in regions with deeper soils. The hotspot analysis indicated that clusters of high and low LVR exist across the province for both species. Although it remains uncertain to what extent the variability of LVR may result from variations in past management practices or in inherent site quality, we argue that efforts to produce high quality timber should be prioritized in sites where LVR is predicted to be the highest.

  1. Alkaline xylan extraction of bleached kraft pulp-effect of extraction time on pulp chemical composition and physical properties%漂白硫酸盐浆的碱性木聚糖抽提对纸浆化学组分和物理性质的影响

    Institute of Scientific and Technical Information of China (English)

    林庆旭; 夏新兴

    2013-01-01

    In this pilot scale study, we examined the effects of alkaline extraction time on xylan removal, pulp and paper properties, and the consequences that need to be addressed when scaling up and intensifying the process. Alkaline extraction of bleached birch kraft pulp yields two fractions:pure polymeric xylan and pulp with reduced xylan content. Our results indicate that a similar amount of xylan can be extracted in 5 min as the amount obtained in 60 min. We found, however, that the shorter extraction time is beneficial to maintain the fiber and paper properties at an acceptable level. This pilot trial demonstrated that the washing procedure of the alkali-treated fibers must be selected with care to avoid causing mechanical damage to fibers and to avoid the loss of fines.%  研究了扩大和强化过程时碱抽提时间对木聚糖去除、纸浆和纸张性能及结果的影响。漂白桦木硫酸盐浆的碱抽提产生了两部分产物:纯木聚糖和木聚糖含量降低的纸浆。研究结果表明:抽提5m in得到的木聚糖量与抽提60m in得到的木聚糖量是相近的;在合理的范围内,缩短提取时间有利于保持纤维和纸张的性能;碱处理纤维的洗涤必须小心进行,以避免造成对纤维的机械损伤,以及细小纤维的流失。

  2. Xylan synthetase activity in differentiated xylem cells of sycamore trees (Acer pseudoplatanus).

    Science.gov (United States)

    Dalessandro, G; Northcote, D H

    1981-01-01

    Particulate enzymic preparations obtained from homogenates of differentiated xylem cells isolated from sycamore trees, catalyzed the formation of a radioactive xylan in the presence of UDP-D-[U-(14)C]xylose as substrate. The synthesized xylan was not dialyzable through Visking cellophane tubing. Successive extraction with cold water, hot water and 5% NaOH dissolved respectively 15, 5 and 80% of the radioactive polymer. Complete acid hydrolysis of the water-insoluble polysaccharide synthesized from UDP-D-[U-(14)C]xylose released all the radioactivity as xylose. β-1,4-Xylodextrins, degree of polymerization 2, 3, 4, 5 and 6, were obtained by partial acid hydrolysis (fuming HCl or 0.1 M HCl) of radioactive xylan. The polymer was hydrolysed to xylose, xylobiose and xylotriose by Driselase which contains 1,4-β xylanase activities. Methylation and then hydrolysis of the xylan released two methylated sugars which were identified as di-O-methyl[(14)C]xylose and tri-O-methyl-[(14)C]xylose, suggesting a 1→4-linked polymer. The linkage was confirmed by periodate oxidation studies. The apparent Km value of the synthetase for UDP-D-xylose was 0.4 mM. Xylan synthetase activity was not potentiated in the presence of a detergent. The enzymic activity was stimulated by Mg(2+) and Mn(2+) ions, although EDTA in the range of concentrations between 0.01 and 1 mM did not affect the reaction rate. It appears that the xylan synthetase system associated with membranes obtained from differentiated xylem cells of sycamore trees may serve for catalyzing the in vivo synthesis of the xylan main chain during the biogenesis of the plant cell wall.

  3. Direct xylan conversion into glycolipid biosurfactants, mannosylerythritol lipids, by Pseudozyma antarctica PYCC 5048(T).

    Science.gov (United States)

    Faria, Nuno Torres; Marques, Susana; Fonseca, César; Ferreira, Frederico Castelo

    2015-04-01

    Mannosylerythritol lipids (MEL) are glycolipid biosurfactants, produced by Pseudozyma spp., with increasing commercial interest. While MEL can be produced from d-glucose and d-xylose, the direct conversion of the respective lignocellulosic polysaccharides, cellulose and xylan, was not reported yet. The ability of Pseudozyma antarctica PYCC 5048(T) and Pseudozyma aphidis PYCC 5535(T) to use cellulose (Avicel(®)) and xylan (beechwood) as carbon and energy source has been assessed along with their capacity of producing cellulolytic and hemicellulolytic enzymes, toward a consolidated bioprocess (CBP) for MEL production. The yeasts assessed were neither able to grow in medium containing Avicel(®) nor produce cellulolytic enzymes under the conditions tested. On contrary, both yeasts were able to efficiently grow in xylan, but MEL production was only detected in P. antarctica PYCC 5048(T) cultures. MEL titers reached 1.3g/l after 10 days in batch cultures with 40g/l xylan, and 2.0g/l in fed-batch cultures with xylan feeding (additional 40g/l) at day 4. High levels of xylanase activities were detected in xylan cultures, reaching 47-62U/ml (31-32U/mg) at 50°C, and still exhibiting more than 10U/ml under physiological temperature (28°C). Total β-xylosidase activities, displayed mainly as wall-bounded and extracellular activity, accounted for 0.154 and 0.176U/ml in P. antarctica PYCC 5048(T) and P. aphidis PYCC 5535(T) cultures, respectively. The present results demonstrate the potential of Pseudozyma spp. for using directly a fraction of lignocellulosic biomass, xylan, and combining in the same bioprocess the production of xylanolytic enzymes with MEL production.

  4. Particulate emissions from the combustion of birch, beech, and spruce logs cause different cytotoxic responses in A549 cells.

    Science.gov (United States)

    Kasurinen, Stefanie; Jalava, Pasi I; Happo, Mikko S; Sippula, Olli; Uski, Oskari; Koponen, Hanna; Orasche, Jürgen; Zimmermann, Ralf; Jokiniemi, Jorma; Hirvonen, Maija-Riitta

    2017-05-01

    According to the World Health Organization particulate emissions from the combustion of solid fuels caused more than 110,000 premature deaths worldwide in 2010. Log wood combustion is the most prevalent form of residential biomass heating in developed countries, but it is unknown how the type of wood logs used in furnaces influences the chemical composition of the particulate emissions and their toxicological potential. We burned logs of birch, beech and spruce, which are used commonly as firewood in Central and Northern Europe in a modern masonry heater, and compared them to the particulate emissions from an automated pellet boiler fired with softwood pellets. We determined the chemical composition (elements, ions, and carbonaceous compounds) of the particulate emissions with a diameter of less than 1 µm and tested their cytotoxicity, genotoxicity, inflammatory potential, and ability to induce oxidative stress in a human lung epithelial cell line. The chemical composition of the samples differed significantly, especially with regard to the carbonaceous and metal contents. Also the toxic effects in our tested endpoints varied considerably between each of the three log wood combustion samples, as well as between the log wood combustion samples and the pellet combustion sample. The difference in the toxicological potential of the samples in the various endpoints indicates the involvement of different pathways of toxicity depending on the chemical composition. All three emission samples from the log wood combustions were considerably more toxic in all endpoints than the emissions from the pellet combustion. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1487-1499, 2017. © 2016 Wiley Periodicals, Inc.

  5. Identification and characterisation of xylanolytic yeasts isolated from decaying wood and sugarcane bagasse in Brazil.

    Science.gov (United States)

    Lara, Carla A; Santos, Renata O; Cadete, Raquel M; Ferreira, Carla; Marques, Susana; Gírio, Francisco; Oliveira, Evelyn S; Rosa, Carlos A; Fonseca, César

    2014-06-01

    In this study, yeasts associated with lignocellulosic materials in Brazil, including decaying wood and sugarcane bagasse, were isolated, and their ability to produce xylanolytic enzymes was investigated. A total of 358 yeast isolates were obtained, with 198 strains isolated from decaying wood and 160 strains isolated from decaying sugarcane bagasse samples. Seventy-five isolates possessed xylanase activity in solid medium and were identified as belonging to nine species: Candida intermedia, C. tropicalis, Meyerozyma guilliermondii, Scheffersomyces shehatae, Sugiyamaella smithiae, Cryptococcus diffluens, Cr. heveanensis, Cr. laurentii and Trichosporon mycotoxinivorans. Twenty-one isolates were further screened for total xylanase activity in liquid medium with xylan, and five xylanolytic yeasts were selected for further characterization, which included quantitative analysis of growth in xylan and xylose and xylanase and β-D-xylosidase activities. The yeasts showing the highest growth rate and cell density in xylan, Cr. laurentii UFMG-HB-48, Su. smithiae UFMG-HM-80.1 and Sc. shehatae UFMG-HM-9.1a, were, simultaneously, those exhibiting higher xylanase activity. Xylan induced the highest level of (extracellular) xylanase activity in Cr. laurentii UFMG-HB-48 and the highest level of (intracellular, extracellular and membrane-associated) β-D-xylosidase activity in Su. smithiae UFMG-HM-80.1. Also, significant β-D-xylosidase levels were detected in xylan-induced cultures of Cr. laurentii UFMG-HB-48 and Sc. shehatae UFMG-HM-9.1a, mainly in extracellular and intracellular spaces, respectively. Under xylose induction, Cr. laurentii UFMG-HB-48 showed the highest intracellular β-D-xylosidase activity among all the yeast tested. C. tropicalis UFMG-HB 93a showed its higher (intracellular) β-D-xylosidase activity under xylose induction and higher at 30 °C than at 50 °C. This study revealed different xylanolytic abilities and strategies in yeasts to metabolise xylan and

  6. Synthesis and Characterization of Periodate-Oxidized Polysaccharides: Dialdehyde Xylan (DAX).

    Science.gov (United States)

    Amer, Hassan; Nypelö, Tiina; Sulaeva, Irina; Bacher, Markus; Henniges, Ute; Potthast, Antje; Rosenau, Thomas

    2016-09-12

    The cleavage of the C2-C3 bond in the building units of 1 → 4-linked polysaccharides by periodate formally results in two aldehyde units, which are present in several masked forms. The structural elucidation of such polysaccharide dialdehydes remains a big challenge. Since polysaccharide derivatives are increasingly applied in materials technology, unveiling the exact structure is of utmost importance. To address this issue for xylan, dialdehyde xylan (DAX, oxidation degree of 91.5%) has been synthesized as water-soluble polymer. The ATR-FTIR spectrum of DAX showed free aldehyde to be absent and exhibited a characteristic absorption at 858 cm(-1) related to hemiacetal groups. By a combination of 1D and 2D NMR techniques, it was confirmed that oxidized xylan is present as poly(2,6-dihydroxy-3-methoxy-5-methyl-3,5-diyl-1,4-dioxane). Based on GPC analysis, the DAX polymer shows a slightly lower molar mass (6.6 kDa) compared to the starting material (7.7 kDa) right after oxidation, and degraded further after one month of storage in 0.1 M NaCl solution (4.3 kDa). The oxidized xylan demonstrated lower thermal stability upon TGA analysis and a greater amount of residual char (20.6%) compared to the unmodified xylan (13.7%).

  7. Finishes for Wood Decks

    Science.gov (United States)

    Mark Knaebe

    2013-01-01

    Wood decks have become an important part of residential construction. Wood decks can add versatile living space to a home and, with minimal maintenance, provide decades of use. However, wood decks are exposed to high levels of stress from severe weather conditions that shrink and swell the wood. Without proper maintenance, wood decks can develop problems such as checks...

  8. Integrated production of wood fuel and pulp wood from young stands; Integroitujen tuotantomenetelmien vertailu

    Energy Technology Data Exchange (ETDEWEB)

    Korpilahti, A. [Metsaeteho Oy, Helsinki (Finland)

    1997-12-01

    The aim of the study was to clarify the competitiveness of different harvesting chains and processing methods of first thinning wood. Great expectations have been laid on integrated production of wood fuel and pulp wood. Results produced in other bioenergy projects were taken into account, and in this project some field experiments on mechanised felling-bunching and compressing of the load of tree sections during forwarding were carried out. The new processing methods, the MASSAHAKE-method and chain-flail delimbing combined with small-scale drum debarking, still are under development giving a rather unstable data for comparisons. Both in pine and birch dominant stands modern multiple tree logging gave the most favourable results when ranking on the bases of the price of pulp chips. Integrated methods were not very far and they have more potential than methods based on harvesting delimbed short wood. When compared on the bases of the production cost of pulp, integrated methods were in general the most favourable because they give good subsidies on the form of bioenergy. (orig.)

  9. Integrated production of merchantable wood and wood fuels in industry; Teollisuuden ainespuun ja puupolttoaineen integroitu tuotanto

    Energy Technology Data Exchange (ETDEWEB)

    Kuvaja, K. [Enso Oy, Imatra (Finland). Forest Dept.

    1997-12-01

    The aim of this project is the economically profitable integrated harvesting of industrial wood and firewood especially in harvesting of small-diameter first thinning wood. The research in 1994 was concentrated on improvement of the quality of the chipping methods based on chain-flail debarking chipping method, and on determination of the possible utilisation targets for the fuel fraction. A reasonably large drum debarking test was also carried out at the industrial scale debarking station of the Enocell Oy. More than 80 000 m{sup 3} of first thinning wood was delivered by Enocell during this project. The quality of wood chips, produced using the chain-flail delimbing method, could be improved in the case of pine nearly to the required quality level, but additional measures are still needed in the case of birch. The fuel fraction deliveries to different points of utilisation was started. The particle size of the fuel fraction appeared to be good after crushing. In 1995 a chain-flail-drum debarking chipping unit was developed to improve and homogenise the quality of chips. (orig.)

  10. Xylan degradation by the human gut Bacteroides xylanisolvens XB1A(T) involves two distinct gene clusters that are linked at the transcriptional level

    National Research Council Canada - National Science Library

    Despres, Jordane; Forano, Evelyne; Lepercq, Pascale; Comtet-Marre, Sophie; Jubelin, Gregory; Chambon, Christophe; Yeoman, Carl J; Berg Miller, Margaret E; Fields, Christopher J; Martens, Eric; Terrapon, Nicolas; Henrissat, Bernard; White, Bryan A; Mosoni, Pascale

    2016-01-01

    .... In order to understand better how these bacteria metabolize xylans in the colon, this study was undertaken to investigate xylan breakdown by the prominent human gut symbiont Bacteroides xylanisolvens XB1A...

  11. Xylan degradation by the human gut Bacteroides xylanisolvens XB1AT involves two distinct gene clusters that are linked at the transcriptional level

    National Research Council Canada - National Science Library

    Despres, Jordane; Forano, Evelyne; Lepercq, Pascale; Comtet-Marre, Sophie; Jubelin, Gregory; Chambon, Christophe; Yeoman, Carl J; Berg Miller, Margaret E; Fields, Christopher J; Martens, Eric; Terrapon, Nicolas; Henrissat, Bernard; White, Bryan A; Mosoni, Pascale

    2016-01-01

    .... In order to understand better how these bacteria metabolize xylans in the colon, this study was undertaken to investigate xylan breakdown by the prominent human gut symbiont Transcriptomic analyses...

  12. Transcriptomic analysis of incised leaf-shape determination in birch.

    Science.gov (United States)

    Mu, Huaizhi; Lin, Lin; Liu, Guifeng; Jiang, Jing

    2013-12-01

    Plant researchers have focused much attention on leaf shape because of its importance in the identification. To evaluate the impact of intraspecies leaf-shape variation on the transcriptome, a series of Betula pendula 'Dalecarlica' and B. pendula saplings were generated through tissue culture. The leaf shapes and transcriptomes of B. pendula 'Dalecarlica' clones were compared with those of B. pendula clones. The leaf shape of B. pendula 'Dalecarlica' was incised and that of B. pendula was ovate. Transcriptome data revealed numerous changes in gene expression between B. pendula 'Dalecarlica' and B. pendula, including upregulation of 8767 unigenes and downregulation of 8379 unigenes in B. pendula 'Dalecarlica'. A pathway analysis revealed that the transport and signal transduction of auxin were altered in 'Dalecarlica', which may have contributed to its altered leaf shape. These results shed light on variation in birch leaf shape and help identify important genes for the genetic engineering of birch trees. © 2013.

  13. In Vitro Antioxidant, Anticoagulant and Antimicrobial Activity and in Inhibition of Cancer Cell Proliferation by Xylan Extracted from Corn Cobs

    Directory of Open Access Journals (Sweden)

    Hugo Alexandre Oliveira Rocha

    2011-12-01

    Full Text Available Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2. Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70% at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05 in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds.

  14. Evaluation of sewage sludge impact on pine and birch development

    OpenAIRE

    Vaitkutė, Dovilė

    2009-01-01

    Sewage sludge could be used in forestry as enrichment of soil properties. It is also expected that sewage sludge which is rich in phosphorus, nitrogen and organic material can enhance the growth of tree seedlings in poor soils. Our study was performed in Taruskos experimental forest site in Panevezys region. The experimental site amended with industrial sewage sludge ten years ago was afforestated with birch and pine seedlings. The aim of our thesis is to evaluate the influence of sewage ...

  15. Synthesis of Pro-Xylane: a new biologically active C-glycoside in aqueous media.

    Science.gov (United States)

    Cavezza, Alexandre; Boulle, Christophe; Guéguiniat, Amélie; Pichaud, Patrick; Trouille, Simon; Ricard, Louis; Dalko-Csiba, Maria

    2009-02-01

    The scope and limitation of Lubineau's reaction were evaluated for the synthesis of C-glycosides (compounds 1-13). Further transformation of side chain carbonyl was also achieved (compounds 16-23). Optimization of these two steps was investigated in xylose case. Some of the compounds were shown to stimulate sulfated glycosaminoglycans (GAGs) synthesis. Compound 20 (called Pro-Xylane) was identified as the best activator of GAGs biosynthesis. Pro-Xylane was developed using environmentally friendly conditions relevant to 'Green-Chemistry' principles and launched on the market in September 2006. This compound is the first example of 'Green' chemical used in cosmetic.

  16. Increase of xylan synthetase activity during xylem differentiation of the vascular cambium of sycamore and poplar trees.

    Science.gov (United States)

    Dalessandro, G; Northcote, D H

    1981-01-01

    The activity of a β-(1-4)-xylan synthetase, a membrane-bound enzymic system, was measured in particulate enzymic preparations (1,000 g and 1,000-100,000 g pellets) obtained from homogenates of cambial cells, differentiating xylem cells and differentiated xylem cells isolated from actively growing trees of sycamore (Acer pseudoplatamus) and poplar (Populus robusta). The specific activity (nmol of xylan formed min(-1) mg(-1) of protein) as well as the activity calculated on a per cell basis (nmol of xylan formed min(-1) cell(-1)) of this enzymic system, markedly increased as cells differentiate from the vascular cambium to xylem. This increase is closely correlated with the enhanced deposition of xylan occurring during the formation of secondary thickening. The possible control of xylan synthesis during the biogenesis of plant cell wall is discussed.

  17. Soil Properties Control Glyphosate Sorption in Soils Amended with Birch Wood Biochar

    DEFF Research Database (Denmark)

    Kahawaththa Gamage, Inoka Damayanthi Kumari; Moldrup, Per; Paradelo, Marcos

    2016-01-01

    , Kd (L kg−1), of the herbicide glyphosate. We measured Kd in equilibrium batch sorption experiments with triplicate soil samples from 20 field plots that received biochar at different application rates (0 to 100 Mg ha−1). The results showed that pure biochar had a lower glyphosate Kd value as compared...... to soils. Yet, at the Kalundborg soils, the application of biochar enhanced the sorption of glyphosate when tested after 7–19 months of soil–biochar interaction. The relative enhancement effect on glyphosate sorption diminished with increasing biochar application rate, presumably due to increased mineral......–biochar interactions. In the Risoe soils, potential biochar effects on glyphosate sorption were affected by a distinct gradient in soil pH (7.4 to 8.3) and electrical conductivity (0.40–0.90 mS cm −1) resulting from a natural CaCO3 gradient. Thus, glyphosate Kd showed strong linear correlation with pH and EC...

  18. Electron paramagnetic resonance and quantitative color investigations of various vacuum heat treated wood species

    Directory of Open Access Journals (Sweden)

    E.I. Kondratyeva, K.R. Safiullin, I.G. Motygullin, A.V. Klochkov, M.S. Tagirov, V.V. Kuzmin

    2015-12-01

    Full Text Available The effect of the heat treatment duration on the electron paramagnetic resonance signal amplitude of free radicals for various wood species was observed. It was found that the amplitude of the electron paramagnetic resonance signal grows linearly with the vacuum heat treatment duration. The quantitative measurements of color changes for various wood species (pine, spruce, larch, birch and small-leaved lime were performed. It is found that results of EPR experiments and color measurements of heat treated samples correlate with each other.

  19. Survival and growth for pubescent birch, pendula birch and common alder growing on farmland areas; Oeverlevnad och tillvaext hos glasbjoerk, vaartbjoerk och klibbal planterade paa aakermark

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Tord

    2000-07-01

    Pendula birches (Betula pendula Roth) and pubescent birches (Betula pubescens Ehrh.) were planted on former farmland. Before planting, the ground was harrowed or the ground was sprayed with terbuthylazine. Tree shelters were used as protection against weeds, voles and wild habitat. Birches treated with terbuthylazine showed the lowest survival. Birches growing in tree shelters were tallest and those growing on spots treated with terbuthylazine were smallest. The diameter at 0.1 m did not differ in a statistically significant way between the treatments. In another experiment with different herbicides, common alder (Alnus glutinosa (L.) Gaertn.) and pendula birch (Betula pendula Roth) were planted on former farmland that had been treated with glyphosate, terbuthylazine and propyzamide or after ground had been harrowed or not treated. In the study on herbicide-treated plants, birch had the highest plant survival. Mostly, species treated with glyphosate were thicker than species treated in other ways. Both species appeared sensitive to terbuthylazine, but not to glyphosate. Birch was not sensitive for propyzamide in opposite to alder. Some practical recommendations concerning afforestation of former farmland, especially weeding, are given.

  20. Organic matter characteristics in boreal forest soils under stands of silver birch, Norway spruce, and Norway spruce with a mixture of silver birch

    Science.gov (United States)

    Smolander, A.; Kitunen, V.

    2012-04-01

    The aim was to study how tree species and a tree species mixture affect microbial C and N transformations and two major plant secondary compound groups, terpenes and phenolic compounds in soil. The study site was a tree-species experiment in middle-eastern part of Finland containing plots of 43-year-old silver birch, Norway spruce and Norway spruce with a mixture of silver birch (22 and 37 % birch of the total stem number). Soil was podzol and humus type mor. Samples were taken from the organic layer. C and N in the microbial biomass, rates of C mineralization (CO2 evolution), net N mineralization and nitrification, and concentrations of total water-soluble phenolic compounds, condensed tannins and different kind of terpenes were measured. Amounts of C and N in the microbial biomass and the rates of C mineralization and net N mineralization were all lower under spruce than birch, and particularly net N mineralization was stimulated by birch mixture. Concentrations of total water-soluble phenolic compounds were on a similar level, irrespective of tree species. However, there were less low-molecular-weight phenolics and more high-molecular-weight phenolics under spruce than birch. Concentrations of condensed tannins and both sesqui- and diterpenes were all higher under spruce than birch but the concentrations of triterpenes were similar in all soils. The difference between tree species was greatest with monoterpenes which were measured from both organic layer and soil atmosphere: high concentrations under spruce and negligible under birch. Birch mixture tended to decrease the concentrations of condensed tannins and mono-, sesqui- and diterpenes.

  1. In situ enzyme aided adsorption of soluble xylan biopolymers onto cellulosic material.

    Science.gov (United States)

    Chimphango, Annie F A; Görgens, J F; van Zyl, W H

    2016-06-05

    The functional properties of cellulose fibers can be modified by adsorption of xylan biopolymers. The adsorption is improved when the degree of biopolymers substitution with arabinose and 4-O-methyl-glucuronic acid (MeGlcA) side groups, is reduced. α-l-Arabinofuranosidase (AbfB) and α-d-glucuronidase (AguA) enzymes were applied for side group removal, to increase adsorption of xylan from sugarcane (Saccharum officinarum L) bagasse (BH), bamboo (Bambusa balcooa) (BM), Pinus patula (PP) and Eucalyptus grandis (EH) onto cotton lint. The AguA treatment increased the adsorption of all xylans by up to 334%, whereas, the AbfB increased the adsorption of the BM and PP by 31% and 44%, respectively. A combination of AguA and AbfB treatment increased the adsorption, but to a lesser extent than achieved with AguA treatment. This indicated that the removal of the glucuronic acid side groups provided the most significant increase in xylan adsorption to cellulose, in particular through enzymatic treatment.

  2. Targeted discovery and functional characterisation of complex-xylan degrading enzymes

    NARCIS (Netherlands)

    Gool, van M.P.

    2012-01-01

    This thesis describes the development of a screening method to discover efficient hemicellulase producers in a wide range of fungi. The method is based on the potential of soil fungi to degrade soluble and insoluble xylan-rich substrates, by assigning various individual enzyme activities. Released m

  3. Facile fabrication and selective detection for cysteine of xylan/Au nanoparticles composite.

    Science.gov (United States)

    Luo, Yuqiong; Shen, Zuguang; Liu, Pai; Zhao, Lihong; Wang, Xiaoying

    2016-04-20

    This work reported a facile and green method to prepare highly stable and uniformly distributed Au nanoparticles (AuNPs), using biopolymer xylan as stabilizing and reducing agent. Full characterizations were performed and the results revealed that AuNPs were well dispersed with the diameters of 10-30nm. The optimal condition was as follows: the ratio of xylan to HAuCl4 was 150mg:15mg, reaction temperature was 80°C and reaction time was 40min. The xylan/AuNPs composite exhibited highly selective and sensitive sensing of cysteine in aqueous solution, it could distinguish cysteine among dozens kinds of amino acids, and the limit of detection (LOD) for cysteine was calculated as 0.57μM. Besides, the xylan/AuNPs composite was applied for Cys detection in human serum. This study provides a new way for high-value utilization of the rich biomass resource and a cheap, rapid and simple method for Cys detection in real biological samples.

  4. Complete genome sequence of the xylan-degrading subseafloor bacterium Microcella alkaliphila JAM-AC0309.

    Science.gov (United States)

    Kurata, Atsushi; Hirose, Yuu; Misawa, Naomi; Wakazuki, Sachiko; Kishimoto, Noriaki; Kobayashi, Tohru

    2016-03-10

    Here we report the complete genome sequence of Microcella alkaliphila JAM-AC0309, which was newly isolated from the deep subseafloor core sediment from offshore of the Shimokita Peninsula of Japan. An array of genes related to utilization of xylan in this bacterium was identified by whole genome analysis.

  5. Ice templated and cross-linked xylan/nanocrystalline cellulose hydrogels.

    Science.gov (United States)

    Köhnke, Tobias; Elder, Thomas; Theliander, Hans; Ragauskas, Arthur J

    2014-01-16

    Structured xylan-based hydrogels, reinforced with cellulose nanocrystals (CNCs), have successfully been prepared from water suspensions by cross-linking during freeze-casting. In order to induce cross-linking during the solidification/sublimation operation, xylan was first oxidized using sodium periodate to introduce dialdehydes. The oxidized xylan was then mixed with CNCs after which the suspension was frozen unidirectionally in order to control the ice crystal formation and by that the pore morphology of the material. Finally the ice crystal templates were removed by freeze-drying. During the freeze-casting process hemiacetal bonds are formed between the aldehyde groups and hydroxyl groups, either on other xylan molecules or on CNCs, which cross-links the system. The proposed cross-linking reaction was confirmed by using cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) spectroscopy. The pore morphology of the obtained materials was analyzed by scanning electron microscopy (SEM). The materials were also tested for compressive strength properties, both in dry and water swollen state. All together this study describes a novel combined freeze-casting/cross-linking process which enables fabrication of nanoreinforced biopolymer-based hydrogels with controlled porosity and 3-D architecture.

  6. Hydrolysis of Wheat Arabinoxylan by Two Acetyl Xylan Esterases from Chaetomium thermophilum

    DEFF Research Database (Denmark)

    Tong, Xiaoxue; Lange, Lene; Grell, Morten Nedergaard

    2015-01-01

    been sequenced, its carbohydrate esterases are not annotated yet. We applied peptide pattern recognition (PPR) tool for sequence analysis of the C. thermophilum genome, and 11 carbohydrate esterase genes were discovered. Furthermore, we cloned and heterologously expressed two putative acetyl xylan...

  7. Properties of polyvinyl alcohol/xylan composite films with citric acid.

    Science.gov (United States)

    Wang, Shuaiyang; Ren, Junli; Li, Weiying; Sun, Runcang; Liu, Shijie

    2014-03-15

    Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6 MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95 × 10(-7)g/(mm(2)h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming.

  8. Selective chemical oxidation and depolymerization of switchgrass [corrected] (Panicum virgatum L.) xylan with [corrected] oligosaccharide product analysis by mass spectrometry.

    Science.gov (United States)

    Bowman, Michael J; Dien, Bruce S; O'Bryan, Patricia J; Sarath, Gautam; Cotta, Michael A

    2011-04-15

    Xylan is a barrier to enzymatic hydrolysis of plant cell walls. It is well accepted that the xylan layer needs to be removed to efficiently hydrolyze cellulose; consequently, pretreatment conditions are (in part) optimized for maximal xylan depolymerization or displacement. Xylan consists of a long chain of β-1,4-linked xylose units substituted with arabinose (typically α-1,3-linked in grasses) and glucuronic acid (α-1,2-linked). Xylan has been proposed to have a structural function in plants and therefore may play a role in determining biomass reactivity to pretreatment. It has been proposed that substitutions along xylan chains are not random and, based upon studies of pericarp xylan, are organized in domains that have specific structural functions. Analysis of intact xylan is problematic because of its chain length (> degree of polymerization (d.p.) 100) and heterogeneous side groups. Traditionally, enzymatic end-point products have been characterized due to the limited products generated. Analysis of resultant arabino-xylo-oligosaccharides by mass spectrometry is complicated by the isobaric pentose sugars that primarily compose xylan. In this report, the variation in pentose ring structures was exploited for selective oxidation of the arabinofuranose primary alcohols followed by acid depolymerization to provide oligosaccharides with modified arabinose branches intact. Switchgrass samples were analyzed by hydrophilic interaction chromatography (HILIC)-liquid chromatography (LC)-mass spectrometry/mass spectrometry (MSMS) and off-line nanospray MS to demonstrate the utility of this chemistry for determination of primary hydroxyl groups on oligosaccharide structures, with potential applications for determining the sequence of arabino-xylo-oligosaccharides present in plant cell wall material.

  9. Wood dusts induce the production of reactive oxygen species and caspase-3 activity in human bronchial epithelial cells.

    Science.gov (United States)

    Pylkkänen, Lea; Stockmann-Juvala, Helene; Alenius, Harri; Husgafvel-Pursiainen, Kirsti; Savolainen, Kai

    2009-08-21

    Wood dusts are associated with several respiratory symptoms, e.g. impaired lung function and asthma, in exposed workers. However, despite the evidence from epidemiological studies, the underlying mechanisms are not well understood. In the present study, we investigated different wood dusts for their capacity to induce cytotoxicity and production of radical oxygen species (ROS) as well as activation of the apoptotic caspase-3 enzyme in human bronchial epithelial cells (BEAS-2B). Dusts from three different tree species widely used in wood industry were studied; birch and oak represented hardwood species, and pine a common softwood species. All the experiments were carried out in three different concentrations (10, 50, and 500 microg/ml) and the analysis was performed after 0.5, 2, 6, and 24h exposure. All wood dusts studied were cytotoxic to human bronchial epithelial cells in a dose-dependent manner after 2 and 6h treatment. Exposure to pine, birch, or oak dust had a significant stimulating effect on the production of ROS. Also an induction in caspase-3 protease activity, one of the central components of the apoptotic cascade, was seen in BEAS-2B cells after 2 and 6h exposure to each of the wood dusts studied. In summary, we demonstrate that dusts from pine, birch and oak are cytotoxic, able to increase the production of ROS and the apoptotic response in human broncho-epithelial cells in vitro. Thus, our current data suggest oxidative stress by ROS as an important mechanism likely to function in wood dust related pulmonary toxicity although details of the cellular targets and cell-particle interactions remain to be solved. It is though tempting to speculate that redox-regulated transcription factors such as NFkappaB or AP-1 may play a role in this wood dust-evoked process leading to apparently induced apoptosis of target cells.

  10. A spectrocolorimetric and chemical study on color modification of heat-treated wood during artificial weathering

    Science.gov (United States)

    Huang, Xianai; Kocaefe, Duygu; Kocaefe, Yasar; Boluk, Yaman; Pichette, Andre

    2012-05-01

    Effect of artificial weathering on the wood surface color modifications of three North American species (jack pine, aspen, and birch) heat-treated under different temperatures was studied by spectrocolorimetric colormeter (datacolor, CHECK TM). Data was analyzed using the reflectance spectra (400-700 nm) as well as the CIE-L*a*b* system and ΔE. Kubelka-Munk (K-M) spectra of samples were recorded as a function of artificial weathering time to obtain the absorption maxima of the chromophore woods formed during artificial weathering. The results were compared with those of the respective untreated (Kiln-dried) species. Analysis of chemical components shows that the lignin percent of jack pine, aspen, and birch increased after heat treatment (28.66-35.9%, 20.27-26.41%, and 19.04-22.71% respectively) which might be due to smaller influence of heat treatment on lignin content than hemicelluloses. This improves the resistance of heat-treated wood to photo-degradation. This is also supported by the smaller change observed in K-M spectra and total color parameters in CIE-L*a*b* system of heat-treated wood samples compared to those of untreated wood when weathered for72 h. However, the lignin percent of heat-treated woods reduce to maximum 2.5% after artificial weathering of 1512 h. This suggests that the weathering degrades most lignin matrix; consequently, both the colors of heat-treated woods and untreated woods are lighter and very similar after a long period of artificial weathering.

  11. Nondestructive wood discrimination: FTIR - Fourier Transform Infrared Spectroscopy in the characterization of different wood species used for artistic objects

    Science.gov (United States)

    Buoso, Maria Crista; de Poli, Mario; Matthaes, Peter; Silvestrin, Luca; Zafiropoulos, Demetre

    2016-09-01

    Wooden artifacts represent a significant component of past cultures. Successful conservation of wooden artifacts depends on the knowledge of wood structure and types. It is critical that conservators know the category of wood that they are treating in order to successfully conserve it. Recently, vibrational spectroscopy has been successfully applied to determine the chemical structure of wood and to characterize wood types. FTIR (Fourier Transform Infrared) is a useful nondestructive or micro-destructive analytical technique providing information about chemical bonding and molecular structure. Its application in the discrimination between softwoods (conifers) and hardwoods (broad-leafs) has already been reported. The aim of the present study was to investigate the potential of FTIR as a tool for the discrimination between different wood types belonging to the same genus. Three different hardwood species, namely poplar (Populus spp), lime (Tilia spp) and birch (Betula spp), were investigated by means of FTIR spectroscopy. The woods were first inspected using a light microscope to certify the wood essence types through micrographic and morphoanatomical features. The FTIR spectra in the 4000 cm-1 to 450 cm-1 region were recorded using a Perkin-Elmer Spectrum 100 spectrometer. To enhance the qualitative interpretation of the IR spectra, second derivatives of all spectra were calculated using the Spectrum software to separate superimposed bands and to extract fine spectral details. To obtain a comprehensive characterization, the essences under investigation were also analyzed by means of Raman Spectroscopy. Clear differences were found in the spectra of the three samples confirming FTIR to be a powerful tool for wood type discrimination.

  12. Specific probiotics alleviate allergic rhinitis during the birch pollen season

    Institute of Scientific and Technical Information of China (English)

    Arthur C Ouwehand; Merja Nermes; Maria Carmen Collado; Nina Rautonen; Seppo Salminen; Erika Isolauri

    2009-01-01

    AIM: To investigate whether birch pollen allergy symptoms are linked with gut microbiota changes and whether probiotics have an effect on these. METHODS: Forty seven children with confirmed birch pollen allergy were randomized to receive either a probiotic combination of Lactobacillus acidophilus ( L. acidophi lus) NCFMTM (ATCC 700396) and Bifidobacterium lactis ( B. lactis) Bl-04 (ATCC SD5219) or placebo in a double-blind manner for 4 mo, starting prior to onset of the birch pollen season. Symptoms were recorded in a diary. Blood samples were taken for analysis of cytokines and eosinophils. Fecal samples were analysed for microbiota components, calprotectin and IgA. Nasal swabs were taken for analysis of eosinophils.RESULTS: The pollen season induced a reduction in Bifidobacterium, Clostridium and Bacteroides which could not be prevented by the probiotic intervention. During the intervention, significantly higher numbers 106 bacteria/g feces ( P < 0.0001) were observed in the probiotic group compared to the placebo group. During May, there was a tendency for fewer subjects,(76.2% vs 95.2%, P = 0.078) to report runny nose,while during June, fewer subjects, 11.1% vs 33.3%,reported nasal blocking in the probiotics group ( P = 0.101). Concomitantly, fewer subjects in the probiotic group had infiltration of eosinophils in the nasal mucosa compared to the placebo group, 57.1%vs 95% ( P = 0.013). Eye symptoms tended to be slightly more frequent in the probiotic group, 12.5 d [interquartile range (IQR) 6-18] vs 7.5 d (IQR 0-11.5)( P = 0.066) during May. Fecal IgA was increased in the placebo group during the pollen season; this increase was prevented by the probiotics ( P = 0.028).CONCLUSION: Birch pollen allergy was shown to be associated with changes in fecal microbiota composition. The specific combination of probiotics used was shown to prevent the pollen-induced infiltration of eosinophils into the nasal mucosa, and indicated a trend for reduced nasal symptoms.

  13. Impact of urbanization of the proteome of birch pollen and its chemotactic activity on human granulocytes

    NARCIS (Netherlands)

    Bryce, M.; Drews, O.; Schenk, M.F.; Menzel, A.; Estrella, N.; Weichenmeier, I.; Smulders, M.J.M.; Buters, J.; Ring, J.; Gorg, A.; Behrendt, H.; Traidl-Hoffmann, C.

    2010-01-01

    Background: Epidemiologic studies reveal a dramatic increase in allergies in the last decades. Air pollution is considered to be one of the factors responsible for this augmentation. The aim of this study was to analyze the impact of urbanization on birch pollen. The birch pollen proteome was invest

  14. 78 FR 15681 - Beaverhead-Deerlodge National Forest, Dillon Ranger District; Montana; Birch, Willow, Lost Project

    Science.gov (United States)

    2013-03-12

    ... Forest Service Beaverhead-Deerlodge National Forest, Dillon Ranger District; Montana; Birch, Willow, Lost... statement. SUMMARY: The Birch, Willow, Lost Project proposes to treat vegetation communities in the four sub.... FR 7476 (Lower Willow Creek) would have 1.7 miles Spot Reconstructed. FR 8200 (Willow Creek)...

  15. Impact of urbanization of the proteome of birch pollen and its chemotactic activity on human granulocytes

    NARCIS (Netherlands)

    Bryce, M.; Drews, O.; Schenk, M.F.; Menzel, A.; Estrella, N.; Weichenmeier, I.; Smulders, M.J.M.; Buters, J.; Ring, J.; Gorg, A.; Behrendt, H.; Traidl-Hoffmann, C.

    2010-01-01

    Background: Epidemiologic studies reveal a dramatic increase in allergies in the last decades. Air pollution is considered to be one of the factors responsible for this augmentation. The aim of this study was to analyze the impact of urbanization on birch pollen. The birch pollen proteome was

  16. Differential response of Aspen and Birch trees to heat stress under elevated carbon dioxide

    Science.gov (United States)

    Joseph N.T. Darbah; Thomas D. Sharkey; Carlo Calfapietra; David F. Karnosky

    2010-01-01

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO2 and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO2 protected photosynthesis of both species against moderate heat stress. Elevated CO...

  17. Field performance of chitinase transgenic silver birches (Betula pendula): resistance to fungal diseases.

    Science.gov (United States)

    Pasonen, H-L; Seppänen, S-K; Degefu, Y; Rytkönen, A; von Weissenberg, K; Pappinen, A

    2004-08-01

    A field trial of 15 transgenic birch lines expressing a sugar beet chitinase IV gene and the corresponding controls was established in southern Finland to study the effects of the level of sugar beet chitinase IV expression on birch resistance to fungal diseases. The symptoms caused by natural infections of two fungal pathogens, Pyrenopeziza betulicola (leaf spot disease) and Melampsoridium betulinum (birch rust), were analysed in the field during a period of 3 years. The lines that had shown a high level of sugar beet chitinase IV mRNA accumulation in the greenhouse also showed high sugar beet chitinase IV expression after 3 years in the field. The level of sugar beet chitinase IV expression did not significantly improve the resistance of transgenic birches to leaf spot disease. Instead, some transgenic lines were significantly more susceptible to leaf spot than the controls. The level of sugar beet chitinase IV expression did have an improving effect on most parameters of birch rust; the groups of lines showing high or intermediate transgene expression were more resistant to birch rust than those showing low expression. This result indicates that the tested transformation may provide a tool for increasing the resistance of silver birch to birch rust.

  18. Evolutionary dynamics of birch (Betula aetnensis Rafin coppices on the Mount Etna (Sicily

    Directory of Open Access Journals (Sweden)

    Bagnato S

    2014-04-01

    Full Text Available Evolutionary dynamics of birch (Betula aetnensis Rafin coppices on the Mount Etna (Sicily. The aim of this paper is to evaluate the dynamics of Etna birch stands (Betula aetnensis Rafin following the cessation of silvicultural activities in the Etna Regional Park (Sicily. We investigated forest structure, natural regeneration, vegetation and deadwood in different forest types. Our findings highlighted three different dynamics for birch populations: stable birch stands in the high mountain area which might represent an edapho-climax forest; progressive dynamic birch stands in the intermediate mountain area, showing a gradual depletion of birch and a concomitant replacement with monospecific stands (calabrian pine, beech, oaks or mixed ones (with birch; pure birch stands (typical that tend to be regressive - especially under stressful conditions - and to be replaced by xerophilous grasslands. Following the cessation of coppicing and with stand ageing, the stumps transformation into more homogeneous stand structures have been increasing. Within the context of protected areas the restoration of coppice selection system (with appropriate adaptations could help to maintain the traditional forest landscape, acting as a silvicultural technique with low environmental and landscape impact.

  19. The features of silver birch Betula verrucosa Ehrh. and downy birch Betula pubescens Ehrh. seed regeneration in subtaiga and forest-steppe of Western Siberia

    Directory of Open Access Journals (Sweden)

    B. E. Chizhov

    2016-12-01

    Full Text Available Article considers results of long-term studies of birch undergrowth in subtaiga subzone and forest-steppe zone of Western Siberia, the features of silver and downy birch seed regeneration under the canopy of parent stands, on logging, burned and abandoned arable lands, and hayfields. The distance of seed dispersal by wind, dynamics of accumulation of self-sown birch after continuous tillage and plough furrows is specified. It was found that seed regeneration under the birch stand canopy is hindered by drying of litter and root competition of the parent stand. A necessary condition for the germination of small seeds and the survival of weak shoots of birches is sufficient rainfall during the period of seed production and careful soil treatment, which provides removal of litter, total removal of herbaceous vegetation and soil reserve of weed seeds: continuous repeated plowing, bulldozing strips or shallow plow furrow with 0.7−1.0 m in width, with their additional cultivation. The most effective way of preparing land for seed regeneration of birch trees in arid steppe conditions is to transfer it under temporary cultivation of grain-crops, providing suppression of permanent weeds. Autumn plowing after harvest will provide annual readiness of the site for seed colonization of the birches. When there is an optimum combination of good seed harvest, rainy weather conditions, and appearance of mass self-sown birch, the land is excluded from the agricultural use. Prerequisites: the presence of seed productive walls of birch with preliminary removal of aspen and undesirable forms of birch. In spring of the next year an inventory is done of wintered self-sown birches, at least on 100 evenly spaced accounting plots. If the self-seeding dies, the site continues to be used by agriculture. Less reliable but acceptable is tillage by bulldozer stripes and furrows with 0.7−1.0 m in width, in a year of abundant seed production, before the start of mass seed

  20. Establishing correspondence in wood: the challenge and some solutions?

    Science.gov (United States)

    Courtin, Gerard M; Fairgrieve, Scott I

    2013-09-01

    Establishing correspondence between the upper portion of a white birch sapling, a suspected weapon, and a potential source from a stand of trees was posed to one of us (GMC). A bending force shattered the sapling, precluding physical matching. Three white birch saplings were taken from the same stand of trees in a similar manner. Correspondence was achieved by measuring the width of the annual rings along four radii from a disk cut above and below the break. The regression coefficient of the data from the two disks from the same sapling was r(2) = 0.95. Regressing the upper disk against the lower disk of two other saplings resulted in r(2) values of 0.26 and 0.17, respectively. The various characteristics that are confined to a wood stem as part of its normal process of growth can be used to eliminate candidate saplings and establish correspondence between two pieces of wood. © 2013 American Academy of Forensic Sciences.

  1. [A relationship between birch pollen counts and meteorological factors in Sapporo].

    Science.gov (United States)

    Shirasaki, Hideaki; Yamamoto, Tetsuo; Saikawa, Etsuko; Seki, Nobuhiko; Asakura, Kohji; Kataura, Akikatsu; Himi, Tetsuo

    2014-05-01

    Occurrence of airborne pollen in Sapporo has been studied for 19 years during the period between 1995 and 2013. There are wide year-to-year variations in the quantities of birch pollens. A simple linear regression with the least squares method was used for studying correlations between the annual quantities of birch pollens and the meteorological factors. A significant positive correlation was found between the hours of sunlight in June of the preceding year and the annual birch pollen concentrations with the correlation coefficient, R = 0.667. Also, we found the significant positive correlation between the hours of sunlight in March and the annual birch pollen concentrations with the correlation coefficient, R = 0.684. These results suggest that the atmospheric birch pollen counts can be predicted from meteorological factors.

  2. A method to derive vegetation distribution maps for pollen dispersion models using birch as an example.

    Science.gov (United States)

    Pauling, A; Rotach, M W; Gehrig, R; Clot, B

    2012-09-01

    Detailed knowledge of the spatial distribution of sources is a crucial prerequisite for the application of pollen dispersion models such as, for example, COSMO-ART (COnsortium for Small-scale MOdeling-Aerosols and Reactive Trace gases). However, this input is not available for the allergy-relevant species such as hazel, alder, birch, grass or ragweed. Hence, plant distribution datasets need to be derived from suitable sources. We present an approach to produce such a dataset from existing sources using birch as an example. The basic idea is to construct a birch dataset using a region with good data coverage for calibration and then to extrapolate this relationship to a larger area by using land use classes. We use the Swiss forest inventory (1 km resolution) in combination with a 74-category land use dataset that covers the non-forested areas of Switzerland as well (resolution 100 m). Then we assign birch density categories of 0%, 0.1%, 0.5% and 2.5% to each of the 74 land use categories. The combination of this derived dataset with the birch distribution from the forest inventory yields a fairly accurate birch distribution encompassing entire Switzerland. The land use categories of the Global Land Cover 2000 (GLC2000; Global Land Cover 2000 database, 2003, European Commission, Joint Research Centre; resolution 1 km) are then calibrated with the Swiss dataset in order to derive a Europe-wide birch distribution dataset and aggregated onto the 7 km COSMO-ART grid. This procedure thus assumes that a certain GLC2000 land use category has the same birch density wherever it may occur in Europe. In order to reduce the strict application of this crucial assumption, the birch density distribution as obtained from the previous steps is weighted using the mean Seasonal Pollen Index (SPI; yearly sums of daily pollen concentrations). For future improvement, region-specific birch densities for the GLC2000 categories could be integrated into the mapping procedure.

  3. Geochemistry of the Birch Creek Drainage Basin, Idaho

    Science.gov (United States)

    Swanson, Shawn A.; Rosentreter, Jeffrey J.; Bartholomay, Roy C.; Knobel, LeRoy L.

    2003-01-01

    The U.S. Survey and Idaho State University, in cooperation with the U.S. Department of Energy, are conducting studies to describe the chemical character of ground water that moves as underflow from drainage basins into the eastern Snake River Plain aquifer (ESRPA) system at and near the Idaho National Engineering and Environmental Laboratory (INEEL) and the effects of these recharge waters on the geochemistry of the ESRPA system. Each of these recharge waters has a hydrochemical character related to geochemical processes, especially water-rock interactions, that occur during migration to the ESRPA. Results of these studies will benefit ongoing and planned geochemical modeling of the ESRPA at the INEEL by providing model input on the hydrochemical character of water from each drainage basin. During 2000, water samples were collected from five wells and one surface-water site in the Birch Creek drainage basin and analyzed for selected inorganic constituents, nutrients, dissolved organic carbon, tritium, measurements of gross alpha and beta radioactivity, and stable isotopes. Four duplicate samples also were collected for quality assurance. Results, which include analyses of samples previously collected from four other sites, in the basin, show that most water from the Birch Creek drainage basin has a calcium-magnesium bicarbonate character. The Birch Creek Valley can be divided roughly into three hydrologic areas. In the northern part, ground water is forced to the surface by a basalt barrier and the sampling sites were either surface water or shallow wells. Water chemistry in this area was characterized by simple evaporation models, simple calcite-carbon dioxide models, or complex models involving carbonate and silicate minerals. The central part of the valley is filled by sedimentary material and the sampling sites were wells that are deeper than those in the northern part. Water chemistry in this area was characterized by simple calcite-dolomite-carbon dioxide

  4. Wood decomposition and fungal community dynamics mediated by temperature and endophytes

    Science.gov (United States)

    Song, Z.; Schilling, J. S.

    2013-12-01

    Wood decomposition is primarily fulfilled by brown rot and white rot fungi in temperate and boreal forests. The competition balance between these fungi determines the patterns of wood decomposition and carbon cycle in forests. But this balance may shift in a warmer future, especially in high latitude forests. Additionally, endophytes may assert influence over the fungal competition through priority effect and interact with the effect of climate change. In this study, we use paper birch and two common fungi to answer two questions 1) How does increased temperature affect the competition between brown rot and white rot fungi? 2) How do endophytes interact with fungi from the soil and influence wood decomposition? A microcosm system was used to simulate competition between Piptoporus betulinus (brown rot fungi) and Fomes fomentarius (white rot fungi) on small birch stem on the effect of increased temperature and endophytes. Activity of P. betulinus was slower in higher temperature, but F. fomentarius was not affected. Character of residue showed that when both fungi were present, wood tend to have white rot in higher temperature. Presence of endophytes significantly reduced the decay rate when they were competing with external fungi, indicating that part of their energy was allocated to interspecies antagonism from metabolizing wood. In the absence of external fungus, endophytes alone caused significant amount of wood decay. Higher temperature also tends to shift the community of endophyte toward more white rot fungi. Our results highlighted the role of endophytes in wood decomposition. Major wood decomposers, not just plant pathogen, may remain dormant in live trees and regain their activity right after tree death. The endophytes could be an important part of assembly history in forming microbial community in dead wood and may have complex interactions with fungi and bacteria in soil. An increased temperature obviously favors white rot fungi, which is in accordance

  5. Promotion of microalgal growth by co-culturing with Cellvibrio pealriver using xylan as feedstock.

    Science.gov (United States)

    Xie, Zhangzhang; Lin, Weitie; Luo, Jianfei

    2016-01-01

    In this work, a Cellvibrio pealriver-microalga co-cultivation mode was used to promote the growths of four microalgae by using xylan as feedstock. After 12days of cultivation, the biomass concentrations of Chlorella sacchrarophila, Chlorella pyrenoidosa and Chlamydomonas reinhardtii in co-cultivation were equal to those in mixotrophic growth on glucose, and the Dunaliella was about 1.6-fold higher than that on glucose. The comparative transcriptomes analysis demonstrated that the xylose and xylan hydrolysates were catalyzed to some active substrates by C. pealriver via some functional enzymes; these active substrates are possibly responsible for the promotion of microalgal growth. This C. pealriver-microalga co-cultivation mode is a potential method to produce low-cost microalgal biodiesel by using hemicellulose as feedstock.

  6. Thermal modification of birch using saturated and superheated steam

    OpenAIRE

    Dagbro, Ola; Torniainen, Petteri; Morén, Tom

    2011-01-01

    During the thermal modification, wood is normally exposed to temperatures between 160 - 220°C. As a result physical and chemical changes are taking place and some of the wood properties are changed. Dimensional stability and weather resistance are improved. On the other hand the mechanical strength properties are usually negatively affected by the treatment. The visual appearance is also changed. There were two different types of thermal modification processes used in this study. One of them ...

  7. Metagenomic and functional analysis of hindgut microbiota of a wood-feeding higher termite

    Energy Technology Data Exchange (ETDEWEB)

    Warnecke, Falk; Warnecke, Falk; Luginbuhl, Peter; Ivanova, Natalia; Ghassemian, Majid; Richardson, Toby H.; Stege, Justin T.; Cayouette, Michelle; McHardy, Alice C.; Djordjevic, Gordana; Aboushadi, Nahla; Sorek, Rotem; Tringe, Susannah G.; Podar, Mircea; Martin, Hector Garcia; Kunin, Victor; Dalevi, Daniel; Madejska, Julita; Kirton, Edward; Platt, Darren; Szeto, Ernest; Salamov, Asaf; Barry, Kerrie; Mikhailova, Natalia; Kyrpides, Nikos C.; Matson, Eric G.; Ottesen, Elizabeth A.; Zhang, Xinning; Hernandez, Myriam; Murillo, Catalina; Acosta, Luis G.; Rigoutsos, Isidore; Tamayo, Giselle; Green, Brian D.; Chang, Cathy; Rubin, Edward M.; Mathur, Eric J.; Robertson, Dan E.; Hugenholtz, Philip; Leadbetter, Jared R.

    2007-10-01

    From the standpoints of both basic research and biotechnology, there is considerable interest in reaching a clearer understanding of the diversity of biological mechanisms employed during lignocellulose degradation. Globally, termites are an extremely successful group of wood-degrading organisms and are therefore important both for their roles in carbon turnover in the environment and as potential sources of biochemical catalysts for efforts aimed at converting wood into biofuels. Only recently have data supported any direct role for the symbiotic bacteria in the gut of the termite in cellulose and xylan hydrolysis. Here we use a metagenomic analysis of the bacterial community resident in the hindgut paunch of a wood-feeding Nasutitermes species to show the presence of a large, diverse set of bacterial genes for cellulose and xylan hydrolysis. Many of these genes were expressed in vivo or had cellulase activity in vitro, and further analyses implicate spirochete and fibrobacter species in gut lignocellulose degradation. New insights into other important symbiotic functions including H{sub 2} metabolism, CO{sub 2}-reductive acetogenesis and N{sub 2} fixation are also provided by this first system-wide gene analysis of a microbial community specialized towards plant lignocellulose degradation. Our results underscore how complex even a 1-{micro}l environment can be.

  8. 从笋壳中提取木聚糖研究%Study on extraction of xylan from bamboo shoot shell

    Institute of Scientific and Technical Information of China (English)

    余能富; 吴能良; 王玉; 涂业苟

    2012-01-01

    Bamboo shoot shell is the waste material of bamboo processing and has a potential usage. Xylan is the main component of hemicellulose in plant cell wall, and is linked through β - 1, 4 wood glycosidic to the main chain of the D - xylose residues polysaccharide complex molecules. We can get functional food Xylooligosaccharides through the degradation of xylan. Using bamboo shoot shell as the raw material, the experiment use alkali extraction after bamboo shoot shell was pretreated. Effects of alkali concentration, extraction temperature, ratio of solid to liquid and extraction time on yield of xylan were analyzed. The conditions of alkali extraction were: alkali concentration 5% , ratio of solid to liquid 1 : 10 (g : mL) , extraction time 3h, extraction temperature 120℃. The yield of xylan from bamboo shoot shell reached 24.77% , which shows that: bamboo shoot shell is a good raw material with the content of 35.08% hemicellulose in it. There is no difference in the hemicellulose content of the bamboo shoot shell and corn cob which is currently the main raw material for production of Xylooligosaccharides. This study provides a solid foundation for bamboo shell resources comprehensive utilization.%竹笋壳是竹笋加工当中的大宗废弃物,是一种极具开发潜力的资源.木聚糖是许多植物细胞壁中半纤维素的主要组分,是由β-1,4木糖苷键连接的以D-木糖残基为主链的复杂分子多聚糖.通过降解木聚糖可以得到功能性食品低聚木糖.本研究以竹笋壳为原料,采用了制备综纤维再碱抽提方法,分析了碱溶液质量分数、固液比、提取温度和提取时间对提取木聚糖得率的影响.碱提取竹笋壳中木聚糖的方法为:碱质量分数为5%,固液比为(g∶mL) 1∶10,提取时间为3h,提取温度为120℃.木聚糖提取率达到原料质量的24.77%.实验结果表明,笋壳中含半纤维素为35.08%,与目前生产低聚木糖的主要原料玉米芯中半纤维素的

  9. Mechanics of Wood Machining

    CERN Document Server

    Csanády, Etele

    2013-01-01

    Wood is one of the most valuable materials for mankind, and since our earliest days wood materials have been widely used. Today we have modern woodworking machine and tools; however, the raw wood materials available are continuously declining. Therefore we are forced to use this precious material more economically, reducing waste wherever possible. This new textbook on the “Mechanics of Wood Machining” combines the quantitative, mathematical analysis of the mechanisms of wood processing with practical recommendations and solutions. Bringing together materials from many sources, the book contains new theoretical and experimental approaches and offers a clear and systematic overview of the theory of wood cutting, thermal loading in wood-cutting tools, dynamic behaviour of tool and work piece, optimum choice of operational parameters and energy consumption, the wear process of the tools, and the general regularities of wood surface roughness. Diagrams are provided for the quick estimation of various process ...

  10. Ion Beam Analyses Of Bark And Wood In Environmental Studies

    Science.gov (United States)

    Lill, J.-O.; Saarela, K.-E.; Harju, L.; Rajander, J.; Lindroos, A.; Heselius, S.-J.

    2011-06-01

    A large number of wood and bark samples have been analysed utilizing particle-induced X-ray emission (PIXE) and particle-induced gamma-ray emission (PIGE) techniques. Samples of common tree species like Scots Pine, Norway Spruce and birch were collected from a large number of sites in Southern and Southwestern Finland. Some of the samples were from a heavily polluted area in the vicinity of a copper-nickel smelter. The samples were dry ashed at 550 °C for the removal of the organic matrix in order to increase the analytical sensitivity of the method. The sensitivity was enhanced by a factor of 50 for wood and slightly less for bark. The ashed samples were pressed into pellets and irradiated as thick targets with a millimetre-sized proton beam. By including the ashing procedure in the method, the statistical dispersion due to elemental heterogeneities in wood material could be reduced. As a by-product, information about the elemental composition of ashes was obtained. By comparing the concentration of an element in bark ash to the concentration in wood ash of the same tree useful information from environmental point of view was obtained. The obtained ratio of the ashes was used to distinguish between elemental contributions from anthropogenic atmospheric sources and natural geochemical sources, like soil and bedrock.

  11. Fire retardants for wood

    Directory of Open Access Journals (Sweden)

    Vlatka Jirouš-Rajković

    2009-06-01

    Full Text Available Along with many advantages, wood as traditional building material also has some disadvantages. One of them is the flammability. The most usual way to improve the fire performance of wood is by treating it with fire retardants that can be applied to wood composite products during manufacture, pressure impregnated into solid wood or wood products or added as a paint or surface coating. Fire retardants are formulated to control ignition, flame spread on the wood surface and to reduce the amount of heat released from wood. Fire retardants cannot make wood non combustible. According to the European reaction-to-fire “Euroclasses”classification system for construction products, wood treated with fire retardant can meet the requirements of Euroclass B, whereas ordinary wood products typically fall into class D. This article attempts to bring together information related to the burning of wood, fire performance of wood, types of fire retardants and mechanism of fire retardancy. Fire retardant coatings and chemical impregnation by pressure-treating are described separately.

  12. Request for wood samples

    NARCIS (Netherlands)

    NN,

    1977-01-01

    In recent years the wood collection at the Rijksherbarium was greatly expanded following a renewed interest in wood anatomy as an aid for solving classification problems. Staff members of the Rijksherbarium added to the collection by taking interesting wood samples with them from their expeditions (

  13. The human eosinophil proteome. Changes induced by birch pollen allergy.

    Science.gov (United States)

    Woschnagg, Charlotte; Forsberg, Jens; Engström, Ake; Odreman, Federico; Venge, Per; Garcia, Rodolfo C

    2009-06-01

    Proteins from human eosinophils were separated bidimensionally and identified by mass spectrometry (336 spots/bands, 98 different proteins). Of these, 24.7% belonged to the cytoskeleton/migration group. Highly basic proteins (11.3%) were concentrated in the granule-containing cell fraction. We detected novel hyperacidic forms of cofilin-1, profilin-1 and adenylyl cyclase-associated protein, and hyperbasic forms of eosinophil-derived neurotoxin/eosinophil protein X and major basic protein homologue. We also found evidence of the triglycosylation of the heavy chain of eosinophil peroxidase. In addition, through comparative 2D image analysis, spot quantification and MS, it was found that hsc70, actin-capping protein and hyperacidic forms of eosinophil peroxidase heavy chain are overexpressed in cells from birch pollen allergic subjects, at the peak of a season. The link between these findings and an increased cellular antigen-presenting capacity and motility are discussed.

  14. Integrated production of merchantable wood and wood fuels in industry; Teollisuuden ainespuun ja puupoltto-aineen integroitu tuotanto

    Energy Technology Data Exchange (ETDEWEB)

    Kuvaja, K. [Enso-Gutzeit Oy, Imatra (Finland). Forest Dept.

    1996-12-31

    The aim of this project is the economically profitable integrated harvesting of industrial wood and firewood especially in harvesting of small-diameter first thinning wood. The research in 1994 was concentrated on improvement of the quality of the chipping methods based on chain-flail debarking chipping method, and on determination of the possible utilization targets for the fuel fraction. A reasonably large drum debarking test was also carried out at the industrial scale debarking station of the Enocell Oy. More than 80 000 m{sup 3} of first thinning wood was delivered by Enocell during this project. The quality of wood chips, produced using the chain-flail delimbing method, could be improved in the case of pine nearly to the required quality level, but additional measures are still needed in the case of birch. The fuel fraction deliveries to different points of utilization was started. The particle size of the fuel fraction appeared to be good after crushing. In 1995 a chain-flail-dry drum debarking chipping unit was developed to improve and homogenize the quality of chips

  15. Direct Emission of Methyvinylketone from Birch (\\textit{betula pendula})

    Science.gov (United States)

    Folkers, A.; Koppmann, R.; Wildt, J.

    2002-12-01

    Volatile organic compounds (VOCs) are of central importance for the chemistry of the troposphere. They have a significant impact on photochemical processes that lead to the formation of ozone and other photooxidants in the planetary boundary layer. With estimated global emission rates of 520 Tg yr {-1} [Guenther \\textit{et al.} 1995], biogenic emissions of short chained oxygenated VOCs (SOVOCs) like methanol, ethanol, acetaldehyde, and acetone cannot be neglected for atmospheric chemistry. In addition to the direct emission by plants SOVOCs are produced by chemical reactions of VOCs in the atmosphere. For some SOVOCs such as methanol, acetone, or leaf alcohols it is known that they have a large biogenic source strength. Other SOVOCs are believed to be only produced by atmospheric processes. For example methacrolein, and methylvinylketone (MVK) are believed to be exclusively produced during atmospheric isoprene oxidation. Thus, up to now the only known source of MVK in the atmosphere is the oxidation of VOCs like isoprene. We analysed SOVOC emissions from different plant species under well defined conditions in our plant chambers and determined the temperature- and light intensity dependence of their emission rates. During these measurements we also observed a direct MVK emission from birch. The emission rates exhibit a temperature and light intensity dependence. Artificial MVK formation was excluded by a series of experiments. Due to the direct emission of MVK probably also from other plant species than birch, measurements of ambient concentrations of this compound have to be carefully investigated. The fact that there may be a primary source for MVK has to be considered in model calculations concerning the photochemistry and the concentrations of OH radicals in the lower troposphere. \\begin{thebibliography}{} \\bibitem[Guenther \\textit{et al.} 1995]{Guenther1995} Guenther, A., Hewitt, C. N., Erickson, D., Fall, R., Geron, C., Graedel, T., Harley, P., Klinger, L

  16. Effect of birch (Betula spp.) and associated rhizoidal bacteria on the degradation of soil polyaromatic hydrocarbons, PAH-induced changes in birch proteome and bacterial community

    Energy Technology Data Exchange (ETDEWEB)

    Tervahauta, Arja I. [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: arja.tervahauta@uku.fi; Fortelius, Carola [EVTEK University of Applied Sciences, Vantaa (Finland); Tuomainen, Marjo [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Akerman, Marja-Leena [EVTEK University of Applied Sciences, Vantaa (Finland); Rantalainen, Kimmo [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Sipilae, Timo [Department of Biological and Environmental Sciences, University of Helsinki (Finland); Lehesranta, Satu J.; Koistinen, Kaisa M.; Kaerenlampi, Sirpa [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Yrjaelae, Kim [Department of Biological and Environmental Sciences, University of Helsinki (Finland)

    2009-01-15

    Two birch clones originating from metal-contaminated sites were exposed for 3 months to soils (sand-peat ratio 1:1 or 4:1) spiked with a mixture of polyaromatic hydrocarbons (PAHs; anthracene, fluoranthene, phenanthrene, pyrene). PAH degradation differed between the two birch clones and also by the soil type. The statistically most significant elimination (p {<=} 0.01), i.e. 88% of total PAHs, was observed in the more sandy soil planted with birch, the clearest positive effect being found with Betula pubescens clone on phenanthrene. PAHs and soil composition had rather small effects on birch protein complement. Three proteins with clonal differences were identified: ferritin-like protein, auxin-induced protein and peroxidase. Differences in planted and non-planted soils were detected in bacterial communities by 16S rRNA T-RFLP, and the overall bacterial community structures were diverse. Even though both represent complex systems, trees and rhizoidal microbes in combination can provide interesting possibilities for bioremediation of PAH-polluted soils. - Birch can enhance degradation of PAH compounds in the rhizosphere.

  17. Construction of low-cost, Mod-OA wood composite wind turbine blades

    Science.gov (United States)

    Lark, R. F.

    1983-01-01

    Two sixty-foot, low-cost, wood composite blades for service on 200 kW Mod-OA wind turbines were constructed. The blades were constructed of epoxy resin-bonded Douglas fir veneers for the leading edge sections, and paper honeycombcored, birch plywood faced panels for the afterbody sections. The blades were joined to the wind turbine hub by epoxy resin-bonded steel load take-off studs embedded into the root end of the blades. The blades were installed on the 200 kW Mod-OA wind turbine facility at Kahuku, Hawaii, The blades completed nearly 8,000 hours of operation over an 18 month period at an average power of 150 kW prior to replacement with another set of wood composite blades. The blades were replaced because of a corrosion failure of the steel shank on one stud. Inspections showed that the wood composite structure remained in excellent condition.

  18. Daily home measurements of exhaled nitric oxide in asthmatic children during natural birch pollen exposure

    DEFF Research Database (Denmark)

    Vahlkvist, Signe; Sinding, Marianne; Skamstrup, Kirsten;

    2006-01-01

    the feasibility, repeatability, accuracy, sensitivity, and biologic plausibility of new handheld equipment for FENO measurements. We studied day-to-day home measurements of FENO during the birch pollen season in children with allergy to birch pollen and a history of mild asthma and rhinoconjunctivitis during......BACKGROUND: Fractional exhaled nitric oxide (FENO) is a sensitive marker of eosinophilic airway inflammation in asthma. Available methods have restricted measurements to the clinic, giving only a snapshot of the disease, which by nature is highly variable. OBJECTIVES: We sought to investigate...... this season, as well as in nonatopic children. METHODS: Eleven children with mild asthma and allergy to birch pollen, performed daily home measurements of FENO for 6 weeks before and during the birch pollen season by using a handheld FENO monitor (NIOX MINO). Additionally, FENO (chemiluminescence equipment...

  19. Quantification of C uptake in subarctic birch forest after setback by an extreme insect outbreak

    DEFF Research Database (Denmark)

    Heliasz, Michal; Johansson, Torbjörn; Lindroth, Anders

    2011-01-01

    The carbon dynamics of northern natural ecosystems contribute significantly to the global carbon balance. Periodic disturbances to these dynamics include insect herbivory. Larvae of autumn and winter moths (Epirrita autumnata and Operophtera brumata) defoliate mountain birch (Betula pubescens) fo...

  20. Bayesian analysis of climate change effects on observed and projected airborne levels of birch pollen

    Science.gov (United States)

    Zhang, Yong; Isukapalli, Sastry S.; Bielory, Leonard; Georgopoulos, Panos G.

    2013-04-01

    A Bayesian framework is presented for modeling effects of climate change on pollen indices such as annual birch pollen count, maximum daily birch pollen count, start date of birch pollen season and the date of maximum daily birch pollen count. Annual mean CO2 concentration, mean spring temperature and the corresponding pollen index of prior year were found to be statistically significant accounting for effects of climate change on four pollen indices. Results suggest that annual productions and peak values from 2020 to 2100 under different scenarios will be 1.3-8.0 and 1.1-7.3 times higher respectively than the mean values for 2000, and start and peak dates will occur around two to four weeks earlier. These results have been partly confirmed by the available historical data. As a demonstration, the emission profiles in future years were generated by incorporating the predicted pollen indices into an existing emission model.

  1. Local variation in mountain birch spring phenology along an altitudinal gradient in northern coastal Fennoscandia

    OpenAIRE

    Sjöskog, Maja Sofia

    2011-01-01

    Currently there is a lack of spring phenology studies covering small-scale altitudinal gradients of mountain birch in coastal northern Fennoscandia, a region characterized by exceptionally high precipitation of snow, which gives reason to investigate the influence of snow cover on birch budburst in this area. Furthermore, ground phenology studies are today increasingly replaced by satellite data studies, but only too rarely is the latter approach properly validated. In order to provide a bett...

  2. Comparison of the protection effectiveness of acrylic polyurethane coatings containing bark extracts on three heat-treated North American wood species: Surface degradation

    Science.gov (United States)

    Kocaefe, Duygu; Saha, Sudeshna

    2012-04-01

    High temperature heat-treatment of wood is a very valuable technique which improves many properties (biological durability, dimensional stability, thermal insulating characteristics) of natural wood. Also, it changes the natural color of wood to a very attractive dark brown color. Unfortunately, this color is not stable if left unprotected in external environment and turns to gray or white depending on the wood species. To overcome this problem, acrylic polyurethane coatings are applied on heat-treated wood to delay surface degradations (color change, loss of gloss, and chemical modifications) during aging. The acrylic polyurethane coatings which have high resistance against aging are further modified by adding bark extracts and/or lignin stabilizer to enhance their effectiveness in preventing the wood aging behavior. The aging characteristic of this coating is compared with acrylic polyurethane combined with commercially available organic UV stabilizers. In this study, their performance on three heat-treated North American wood species (jack pine, quaking aspen and white birch) are compared under accelerated aging conditions. Both the color change data and visual assessment indicate improvement in protective characteristic of acrylic polyurethane when bark extracts and lignin stabilizer are used in place of commercially available UV stabilizer. The results showed that although acrylic polyurethane with bark extracts and lignin stabilizer was more efficient compared to acrylic polyurethane with organic UV stabilizers in protecting heat-treated jack pine, it failed to protect heat-treated aspen and birch effectively after 672 h of accelerated aging. This degradation was not due to the coating adhesion loss or coating degradation during accelerated aging; rather, it was due to the significant degradation of heat-treated aspen and birch surface beneath this coating. The XPS results revealed formation of carbonyl photoproducts after aging on the coated surfaces and

  3. Super-Protective Child-Rearing by Japanese Bess Beetles, Cylindrocaulus patalis: Adults Provide Their Larvae with Chewed and Predigested Wood.

    Science.gov (United States)

    Mishima, Tatsuya; Wada, Noriko; Iwata, Ryûtarô; Anzai, Hirosi; Hosoya, Tadatsugu; Araya, Kunio

    2016-04-26

    Beetles of the family Passalidae (Coleoptera: Scarabaeoidea) are termed subsocial. The insects inhabit rotten wood as family groups consisting of the parents and their offspring. The Japanese species Cylindrocaulus patalis has the lowest fecundity among passalids because siblicide occurs among the first-instar larvae; accordingly, parental care toward the survived larva is the highest among Passalidae. To clarify the nutritional relationships between the parents and their offspring, we investigated their ability to digest three types of polysaccharides that are components of wood (cellulose and β-1,4-xylan) and fungal cell walls (β-1,3-glucan). Although carboxymethyl-cellulase activity was barely detectable, β-xylosidase, β-glucosidase, β-1,4-xylanase and β-1,3-glucanase activities were clearly detected in both adults and larvae. Because the activities of enzymes that digest β-1,3-glucan were much higher than those for degrading β-1,4-xylan, in both adults and larvae, it is concluded that they are mainly fungivorous. Furthermore, these digestive enzymatic activities in second- and third-instar larvae were much lower than they were in adults. Although all larval instars grew rapidly when fed chewed wood by their parents, larvae ceased growing and died when fed only artificially ground wood meals. We conclude that the larvae are assumed to be provided with chewed predigested wood in which β-1,3-glucan is degraded by parental enzymes.

  4. Super-Protective Child-Rearing by Japanese Bess Beetles, Cylindrocaulus patalis: Adults Provide Their Larvae with Chewed and Predigested Wood

    Directory of Open Access Journals (Sweden)

    Tatsuya Mishima

    2016-04-01

    Full Text Available Beetles of the family Passalidae (Coleoptera: Scarabaeoidea are termed subsocial. The insects inhabit rotten wood as family groups consisting of the parents and their offspring. The Japanese species Cylindrocaulus patalis has the lowest fecundity among passalids because siblicide occurs among the first-instar larvae; accordingly, parental care toward the survived larva is the highest among Passalidae. To clarify the nutritional relationships between the parents and their offspring, we investigated their ability to digest three types of polysaccharides that are components of wood (cellulose and β-1,4-xylan and fungal cell walls (β-1,3-glucan. Although carboxymethyl-cellulase activity was barely detectable, β-xylosidase, β-glucosidase, β-1,4-xylanase and β-1,3-glucanase activities were clearly detected in both adults and larvae. Because the activities of enzymes that digest β-1,3-glucan were much higher than those for degrading β-1,4-xylan, in both adults and larvae, it is concluded that they are mainly fungivorous. Furthermore, these digestive enzymatic activities in second- and third-instar larvae were much lower than they were in adults. Although all larval instars grew rapidly when fed chewed wood by their parents, larvae ceased growing and died when fed only artificially ground wood meals. We conclude that the larvae are assumed to be provided with chewed predigested wood in which β-1,3-glucan is degraded by parental enzymes.

  5. Vegetation of birch and aspen forests in the Pinega State Reserve

    Directory of Open Access Journals (Sweden)

    Sergey Yu. Popov

    2017-05-01

    Full Text Available The Pinega State Nature Reserve (Russia is located in the Arkhangelsk region in the northern taiga subzone. Together with spruce forests and mires, birch forests represent one of the most wide-spread plant communities of its territory. Birch forests cover 24.6% of the Reserve's area. Aspen forests are rare plant communities in the Pinega Reserve. These forests cover only 0.9% of the whole Reserve's area. The birch and aspen forests vegetation has been classified based on 82 relevès. Eleven associations could be distinguished, which represent six groups of associations. Detailed characteristics of these syntaxa are provided including their biodiversity analysis. The analysis allowed establishing that the revealed syntaxa differ in relation to habitat environmental conditions: e.g., soil moisture, trophicity, nitrogen saturation and soil acidity. Sphagnum and blueberry birch forests proved to be the poorest in nitrogen, in contrast to the richest humidoherbaceous and broad-grassed groups of birch forest associations. Broad-grassed birch forests in the Pinega Reserve inhabit the most drained locations, while humidoherbaceous and Sphagnum forests occur in lesser drained locations.

  6. Determination of some significant batch culture conditions affecting acetyl-xylan esterase production by Penicillium notatum NRRL-1249

    Directory of Open Access Journals (Sweden)

    Akhtar MN

    2011-05-01

    Full Text Available Abstract Background Acetyl-xylan esterase (AXE, EC 3.1.1.72 hydrolyses acetate group from the linear chain of xylopyranose residues bound by β-1,4-linkage. The enzyme finds commercial applications in bio-bleaching of wood pulp, treating animal feed to increase digestibility, processing food to increase clarification and converting lignocellulosics to feedstock and fuel. In the present study, we report on the production of an extracellular AXE from Penicillium notatum NRRL-1249 by solid state fermentation (SSF. Results Wheat bran at a level of 10 g (with 4 cm bed height was optimized as the basal substrate for AXE production. An increase in enzyme activity was observed when 7.5 ml of mineral salt solution (MSS containing 0.1% KH2PO4, 0.05% KCl, 0.05% MgSO4.7H2O, 0.3% NaNO3, 0.001% FeSO4.2H2O and 0.1% (v/w Tween-80 as an initial moisture content was used. Various nitrogen sources including ammonium sulphate, urea, peptone and yeast extract were compared for enzyme production. Maximal enzyme activity of 760 U/g was accomplished which was found to be highly significant (p ≤ 0.05. A noticeable enhancement in enzyme activity was observed when the process parameters including incubation period (48 h, initial pH (5, 0.2% (w/w urea as nitrogen source and 0.5% (v/w Tween-80 as a stimulator were further optimized using a 2-factorial Plackett-Burman design. Conclusion From the results it is clear that an overall improvement of more than 35% in terms of net enzyme activity was achieved compared to previously reported studies. This is perhaps the first report dealing with the use of P. notatum for AXE production under batch culture SSF. The Plackett-Burman model terms were found highly significant (HS, suggesting the potential commercial utility of the culture used (df = 3, LSD = 0.126.

  7. Xylan oligosaccharides and cellobiohydrolase I (TrCel7A interaction and effect on activity

    Directory of Open Access Journals (Sweden)

    Baumann Martin J

    2011-10-01

    Full Text Available Abstract Background The well-studied cellulase mixture secreted by Trichoderma reesei (anamorph to Hypocrea jecorina contains two cellobiohydolases (CBHs, cellobiohydrolase I (TrCel7A and cellobiohydrolase II (TrCeI6A, that are core enzymes for the solubilisation of cellulose. This has attracted significant research interest because of the role of the CBHs in the conversion of biomass to fermentable sugars. However, the CHBs are notoriously slow and susceptible to inhibition, which presents a challenge for the commercial utilisation of biomass. The xylans and xylan fragments that are also present in the biomass have been suggested repeatedly as one cause of the reduced activity of CHBs. Yet, the extent and mechanisms of this inhibition remain poorly elucidated. Therefore, we studied xylan oligosaccharides (XOSs of variable lengths with respect to their binding and inhibition of both TrCel7A and an enzyme variant without the cellulose-binding domain (CBM. Results We studied the binding of XOSs to TrCel7A by isothermal titration calorimetry. We found that XOSs bind to TrCel7A and that the affinity increases commensurate with XOS length. The CBM, on the other hand, did not affect the affinity significantly, which suggests that XOSs may bind to the active site. Activity assays of TrCel7A clearly demonstrated the negative effect of the presence of XOSs on the turnover number. Conclusions On the basis of these binding data and a comparison of XOS inhibition of the activity of the two enzyme variants towards, respectively, soluble and insoluble substrates, we propose a competitive mechanism for XOS inhibition of TrCel7A with phosphoric swollen cellulose as a substrate.

  8. Lignification and tension wood.

    Science.gov (United States)

    Pilate, Gilles; Chabbert, Brigitte; Cathala, Bernard; Yoshinaga, Arata; Leplé, Jean-Charles; Laurans, Françoise; Lapierre, Catherine; Ruel, Katia

    2004-01-01

    Hardwood trees are able to reorient their axes owing to tension wood differentiation. Tension wood is characterised by important ultrastructural modifications, such as the occurrence in a number of species, of an extra secondary wall layer, named gelatinous layer or G-layer, mainly constituted of cellulose microfibrils oriented nearly parallel to the fibre axis. This G-layer appears directly involved in the definition of tension wood mechanical properties. This review gathers the data available in the literature about lignification during tension wood formation. Potential roles for lignin in tension wood formation are inferred from biochemical, anatomical and mechanical studies, from the hypotheses proposed to describe tension wood function and from data coming from new research areas such as functional genomics.

  9. Deciduous birch canopy as unexpected contributor to stand level atmospheric reactivity in boreal forests

    Science.gov (United States)

    Bäck, Jaana; Taipale, Ditte; Aalto, Juho

    2017-04-01

    In boreal forests, deciduous trees such as birches may in future climate become more abundant due to their large biomass production capacity, relatively good resource use ability and large acclimation potential to elevated CO2 levels and warmer climate. Increase in birch abundance may lead to unpredicted consequences in atmospheric composition. Currently it is acknowledged that conifers such as Scots pine and Norway spruce are important sources for volatile organic compounds (VOCs), especially monoterpenes, throughout the year, although the strong temperature relationships implies that emissions are highest in summertime. However, the dynamics of the deciduous birch foliage VOC emissions and their relationship with environmental drivers during the development, maturation and senescence of foliage has not been well analyzed. Long-term measurements of birch, which are unfortunately very sparse, can provide very useful information for the development of biosphere-atmosphere models that simulate boreal and subarctic forested areas where birch is often a sub-canopy species, occurs as a mixture among conifers or forms even pure stands in the higher latitudes. We measured the branch level VOC emissions from a mature Silver birch with proton transfer reaction mass spectrometer during 2014 and 2015 at the SMEAR II station (Station for Measuring Ecosystem-Atmosphere Relations), southern Finland. Our results showed that the Silver birch foliage is a huge source for both short-chained volatiles such as methanol, acetaldehyde and acetone, as well as for monoterpenes. The mean emission rates from birch leaves were 5 to 10 times higher than the corresponding emissions from Scots pine shoots. We compared several semi-empirical model approaches for determining the birch foliage monoterpene standardized emission potentials, and utilized the continuous emission measurements from the two growing seasons for development of a novel algorithm which accounts for the leaf development and

  10. Production of xylan degrading endo-1, 4-β-xylanase from thermophilic Geobacillus stearothermophilus KIBGE-IB29

    Directory of Open Access Journals (Sweden)

    Zainab Bibi

    2014-10-01

    Full Text Available Xylan degrading bacterial strain was isolated from soil and identified as Geobacillus stearothermophilus KIBGE-IB29 on the basis of morphological, biochemical and 16S rDNA sequence analysis. Optimization of medium and culture conditions in submerged fermentation was investigated for maximum endo-1, 4-β-xylanase production. High yield of xylan degrading endo-1, 4-β-xylanase was achieved at 60 °C and pH-6.0 with 24 h of fermentation. Maximum enzyme was produced using 0.5% xylan as a carbon source, 0.5% peptone, 0.2% yeast extract and 0.1% meat extract as nitrogen sources. Di-potassium hydrogen phosphate (0.25%, calcium chloride (0.01%, potassium hydrogen phosphate (0.05% and ammonium sulfate (0.05% were also incorporated in the fermentation medium to enhance the enzyme production.

  11. Isolation and characterization of xylan-degrading strains of Butyrivibrio fibrisolvens from a napier grass-fed anaerobic digester

    Energy Technology Data Exchange (ETDEWEB)

    Sewell, G.W.; Aldrich, H.C.; Williams, D.; Mannarelli, B.; Wilkie, A.; Hespell, R.B.; Smith, P.H.; Ingram, L.O.

    1988-05-01

    Six new xylanolytic bacterial strains have been isolated from a Napier grass-fed anaerobic digester. These strains were identified as Butyrivibrio fibrisolvens and were similar in many respects to ruminal isolates described previously. The new isolates exhibited a high degree of DNA homology with several ruminal strains of B. fibrisolvens. Xylan or xylose was required to induce the production of enzymes for xylan degradation, xylanase and xylosidase. Production of these was repressed in the presence of glucose. Xylanase activity was predominantly extracellular, while that of xylosidases was cell associated. The new isolates of B. fibrisolvens grew well in defined medium containing xylan as the sole carbon source and did not produce obvious slime or capsular layers. These strains may be useful for future genetic investigations.

  12. Complex geometries in wood

    DEFF Research Database (Denmark)

    Tamke, Martin; Ramsgaard Thomsen, Mette; Riiber Nielsen, Jacob

    2009-01-01

    The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust parame...... parametric model and a generic design language a later explored the possibilities to construct complex shaped geometries with self registering joints on modern wood crafting machines. The research was carried out as collaboration with industrial partners....

  13. Wood Decay Fungi Restore Essential Calcium to Acidic Soils in Northern New England

    Directory of Open Access Journals (Sweden)

    Walter C. Shortle

    2015-07-01

    Full Text Available The depletion of root-available calcium in northern forests soils exposed to decades of increased acid deposition adversely affects forest health and productivity. Laboratory studies indicated the potential of wood-decay fungi to restore lost calcium to the rooting zone of trees. This study reports changes in concentrations of Ca, Mg, and K during decay of sapwood of spruce, maple, hemlock, and birch at two locations in northern New England, USA. Concentrations of exchangeable Ca, Mg, and Al in decayed wood residues after 10 and 12 years of ground contact were also compared. Significant loss of mass indicated by decreasing wood density occurred after two to eight years in conifers and after only two years in hardwoods. A significant gain in wood K was observed at two years, but the gain was not sustained. A significant gain in Ca concentration occurred by six years and that gain was sustained for 12 years. Concentrations of Mg varied. No significant difference in exchangeable Ca concentration was observed between decayed wood residue of spruce and maple and the forest floor. However, decayed wood residue had a much lower molar Al/Ca ratio, a conditional characteristic of sites with high root-available Ca.

  14. Moisture Transport in Wood

    DEFF Research Database (Denmark)

    Astrup, T.; Hansen, K. K.; Hoffmeyer, P.

    2005-01-01

    Modelling of moisture transport in wood is of great importance as most mechanical and physical properties of wood depend on moisture content. Moisture transport in porous materials is often described by Ficks second law, but several observations indicate that this does not apply very well to wood....... Recently at the Technical University of Denmark, Department of Civil Engineering, a new model for moisture transport in wood has been developed. The model divides the transport into two phases, namely water vapour in the cell lumens and bound water in the cell walls....

  15. Moisture Transport in Wood

    DEFF Research Database (Denmark)

    Astrup, T.; Hansen, K. K.; Hoffmeyer, P.;

    2005-01-01

    Modelling of moisture transport in wood is of great importance as most mechanical and physical properties of wood depend on moisture content. Moisture transport in porous materials is often described by Ficks second law, but several observations indicate that this does not apply very well to wood....... Recently at the Technical University of Denmark, Department of Civil Engineering, a new model for moisture transport in wood has been developed. The model divides the transport into two phases, namely water vapour in the cell lumens and bound water in the cell walls....

  16. Effects of birch tar oils on soil organisms and plants

    Directory of Open Access Journals (Sweden)

    M. HAGNER

    2008-12-01

    Full Text Available The use of birch tar oil (BTO is a new innovation in plant and animal protection working against various weeds, harmful insects and rodents. Due to its novelty as a biocide/repellent/plant protection product, no comprehensive information on the effects of BTO on non-target soil organisms is available. In this study we examined the impact of BTO on non-target soil organisms (enchytraeids, nematodes and soil microbes and plants using laboratory toxicity tests and field experiments. In addition, we determined the LC50 value of BTO to the earthworm Aporrectodea caliginosa and the EC50 value of BTO to the offspring production of the collembolan Folsomia candida. The effects of BTO on soil fauna were mostly insignificant. BTO seemed to be detrimental to the growth of plants directly after application, but this effect was short-term; after a period of 2.5 months, the growth of most of the plant species recovered completely from the application. The LC50 for A. caliginosa was 6560 mg BTO kg-1 dry soil and EC50 for juvenile production of F. candida was 5100 mg BTO kg-1 dry soil. The results indicate that the risk caused by BTOs (concentration 500-1360 L ha-1 to the soil environment is insignificant and short-term as compared to the many chemical products applied for similar purposes.;

  17. The Clinical Impact of Bet v 6 in Birch Pollen-Sensitized Patients.

    Science.gov (United States)

    Gellrich, Donata; Eder, Katharina; San Nicoló, Marion; Berghaus, Alexander; Gröger, Moritz

    2017-01-01

    Bet v 6, a minor birch pollen allergen, is commercially available for allergen-specific IgE antibody testing. However, there is hardly any literature on the clinical impact of Bet v 6. The aim of the present study was to analyze if testing specific IgE against Bet v 6 can add valuable benefit to the standard diagnostics of birch pollen-sensitized patients, especially in patients with unknown sensitization-eliciting allergens. Birch pollen-sensitized patients with missing IgE reactivity against Bet v 1, 2, and 4 were tested for specific IgE antibodies against Bet v 6. For comparison, an equal number of randomly selected patients with birch pollen sensitization, regardless of their individual sensitization patterns, were tested for specific anti-Bet v 6. Of 57 cases with missing reactivity against the standard birch pollen allergens, 2 patients were positive for Bet v 6. In the representative sample, 3 patients showed specific IgE against Bet v 6 - resulting in a total prevalence of 5%. None of the Bet v 6-positive patients showed allergic symptoms after exposure to birch pollen or an oral allergy syndrome. An increased prevalence of asthma and a higher degree of sensitization were the only distinctive clinical features in Bet v 6-positive patients. Among birch pollen-sensitized patients, the prevalence of specific IgE against Bet v 6 is low. Further, sensitization to Bet v 6, which shows characteristics of a panallergen, remains clinically silent. Therefore, determination of anti-Bet v 6 is not considered useful in the clinical routine. © 2017 S. Karger AG, Basel.

  18. Integrated production method for wood fuel and pulp wood in Northern Finland; Polttojakeen hankinta puun yhdistelmaekorjuussa ja integroitu energiapuun tuotantomenetelmae Pohjois-Suomessa

    Energy Technology Data Exchange (ETDEWEB)

    Hooli, A. [Hooli Oy, Kemi (Finland); Kuitto, P.J. [VTT Energy, Jyvaeskylae (Finland); Ranta, T. [Finntech Ltd. Oy, Jyvaeskylae (Finland)

    1996-12-31

    Chip production company Hooli Ltd. has built an innovative mobile chain-flail delimbing-debarking-unit which includes also a hammer crusher for wood fuel. This integrated production method for wood fuel and pulp wood based on that unit has been planned especially for the circumstances where the power or heating plants are near and the pulp mills more remote from the wood processing sites. The trees are felt into bunches and transported as whole trees or tree-sections to the roadside. The Hooli-unit delimbs and debarks the trees using multi-tree processing. The optimal bark content of Scot pine bolts after processing is under 1 %. All green branches, stops and bark are directly crushed into wood fuel in the same unit. Fuel chips are carried to the nearest power plant. The debarked bolts are transported to the pulpmills in the form of roundwood or pulpchips, thus giving better economy for the whole method. Based on first field experiments in 1995 this method has operated well. However, there are still development work ahead: e.g. good debarking quality of birch and spruce in the winter conditions. To attain the targets of the project looks promising. The project is carried out as joint project between Hooli Ltd, Finntech Ltd. Oy, the Finnish Forest Research Institute, Veitsiluoto Ltd and VTT Energy. The chain-flail delimbing-debarking-crushing unit was built at Tervolan Konepaja Ky

  19. Compost Grown Agaricus bisporus Lacks the Ability to Degrade and Consume Highly Substituted Xylan Fragments

    Science.gov (United States)

    de Vries, Ronald P.; Gruppen, Harry; Kabel, Mirjam A.

    2015-01-01

    The fungus Agaricus bisporus is commercially grown for the production of edible mushrooms. This cultivation occurs on compost, but not all of this substrate is consumed by the fungus. To determine why certain fractions remain unused, carbohydrate degrading enzymes, water-extracted from mushroom-grown compost at different stages of mycelium growth and fruiting body formation, were analyzed for their ability to degrade a range of polysaccharides. Mainly endo-xylanase, endo-glucanase, β-xylosidase and β-glucanase activities were determined in the compost extracts obtained during mushroom growth. Interestingly, arabinofuranosidase activity able to remove arabinosyl residues from doubly substituted xylose residues and α-glucuronidase activity were not detected in the compost enzyme extracts. This correlates with the observed accumulation of arabinosyl and glucuronic acid substituents on the xylan backbone in the compost towards the end of the cultivation. Hence, it was concluded that compost grown A. bisporus lacks the ability to degrade and consume highly substituted xylan fragments. PMID:26237450

  20. Compost Grown Agaricus bisporus Lacks the Ability to Degrade and Consume Highly Substituted Xylan Fragments.

    Science.gov (United States)

    Jurak, Edita; Patyshakuliyeva, Aleksandrina; de Vries, Ronald P; Gruppen, Harry; Kabel, Mirjam A

    2015-01-01

    The fungus Agaricus bisporus is commercially grown for the production of edible mushrooms. This cultivation occurs on compost, but not all of this substrate is consumed by the fungus. To determine why certain fractions remain unused, carbohydrate degrading enzymes, water-extracted from mushroom-grown compost at different stages of mycelium growth and fruiting body formation, were analyzed for their ability to degrade a range of polysaccharides. Mainly endo-xylanase, endo-glucanase, β-xylosidase and β-glucanase activities were determined in the compost extracts obtained during mushroom growth. Interestingly, arabinofuranosidase activity able to remove arabinosyl residues from doubly substituted xylose residues and α-glucuronidase activity were not detected in the compost enzyme extracts. This correlates with the observed accumulation of arabinosyl and glucuronic acid substituents on the xylan backbone in the compost towards the end of the cultivation. Hence, it was concluded that compost grown A. bisporus lacks the ability to degrade and consume highly substituted xylan fragments.

  1. Production of xylooligosaccharides from enzymatic hydrolysis of xylan by white-rot fungi Pleurotus - DOI: 10.4025/actascitechnol.v32i1.7648

    Directory of Open Access Journals (Sweden)

    Cristiano Ragagnin de Menezes

    2009-12-01

    Full Text Available Hemicellulose consists of non-cellulosic polysaccharides, with xylans and mannans as their main examples. In nature, xylan can be first degraded to xylooligosaccharides and finally to xylose by certain microorganisms. White-rot fungi basidiomycetes Pleurotus sp. BCCB068 and Pleurotus tailandia were used to degrade oat-spelts xylan under submerged fermentation for a period of 40 days. The study obtained activities of endo-1,4-ß-xylanase and ß-xylosidase and determination of xylan products by degradation. The fungi reached significant levels of xylan degradation by Pleurotus sp. BCCB068 (75.1% and P. tailandia (73.4%, following formations of xylooligosaccharides and sugar monomers. These Pleurotus strains proved to be a feasible alternative for biotechnological processes related to degradation of hemicellulose sources.

  2. The role of novel forest ecosystems in the conservation of wood-inhabiting fungi in boreal broadleaved forests.

    Science.gov (United States)

    Juutilainen, Katja; Mönkkönen, Mikko; Kotiranta, Heikki; Halme, Panu

    2016-10-01

    The increasing human impact on the earth's biosphere is inflicting changes at all spatial scales. As well as deterioration and fragmentation of natural biological systems, these changes also led to other, unprecedented effects and emergence of novel habitats. In boreal zone, intensive forest management has negatively impacted a multitude of deadwood-associated species. This is especially alarming given the important role wood-inhabiting fungi have in the natural decay processes. In the boreal zone, natural broad-leaved-dominated, herb-rich forests are threatened habitats which have high wood-inhabiting fungal species richness. Fungal diversity in other broadleaved forest habitat types is poorly known. Traditional wood pastures and man-made afforested fields are novel habitats that could potentially be important for wood-inhabiting fungi. This study compares species richness and fungal community composition across the aforementioned habitat types, based on data collected for wood-inhabiting fungi occupying all deadwood diameter fractions. Corticioid and polyporoid fungi were surveyed from 67 130 deadwood particles in four natural herb-rich forests, four birch-dominated wood pastures, and four birch-dominated afforested field sites in central Finland. As predicted, natural herb-rich forests were the most species-rich habitat. However, afforested fields also had considerably higher overall species richness than wood pastures. Many rare or rarely collected species were detected in each forest type. Finally, fungal community composition showed some divergence not only among the different habitat types, but also among deadwood diameter fractions. Synthesis and applications: In order to maintain biodiversity at both local and regional scales, conserving threatened natural habitat types and managing traditional landscapes is essential. Man-made secondary woody habitats could provide the necessary resources and serve as surrogate habitats for many broadleaved deadwood

  3. Mineralization of fossil wood

    NARCIS (Netherlands)

    Buurman, P.

    1972-01-01

    Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points t

  4. Wood supply and demand

    Science.gov (United States)

    Peter J. Ince; David B. McKeever

    2011-01-01

    At times in history, there have been concerns that demand for wood (timber) would be greater than the ability to supply it, but that concern has recently dissipated. The wood supply and demand situation has changed because of market transitions, economic downturns, and continued forest growth. This article provides a concise overview of this change as it relates to the...

  5. Heat sterilization of wood

    Science.gov (United States)

    Xiping Wang

    2010-01-01

    Two important questions should be considered in heat sterilizing solid wood materials: First, what temperature–time regime is required to kill a particular pest? Second, how much time is required to heat the center of any wood configuration to the kill temperature? The entomology research on the first question has facilitated the development of international standards...

  6. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, Joseph N.T., E-mail: darbah@ohio.ed [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States); Department of Environmental and Plant Biology, Ohio University, 315 Porter Hall, Athens, OH 45701 (United States); Sharkey, Thomas D. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Calfapietra, Carlo [Institute of Agro-Environmental and Forest Biology (IBAF), National Research Council (CNR), Via Salaria km 29300, 00016 Monterotondo Scalo, Roma (Italy); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-04-15

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO{sub 2} and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO{sub 2} protected photosynthesis of both species against moderate heat stress. Elevated CO{sub 2} increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 deg. C) decreased all of these parameters in birch regardless of CO{sub 2} treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO{sub 2} were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO{sub 2}. Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. - We report that elevated CO{sub 2} confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

  7. Proteomic profiling of birch (Betula verrucosa) pollen extracts from different origins.

    Science.gov (United States)

    Erler, Anja; Hawranek, Thomas; Krückemeier, Leif; Asam, Claudia; Egger, Matthias; Ferreira, Fátima; Briza, Peter

    2011-04-01

    Pollen of the European white birch is a major source of spring pollinosis in Europe. Pollen-allergy diagnosis and treatment by specific immunotherapy commonly rely on extracts of natural origin. To gain insight into the protein content and its variability, we evaluated the profile of allergenic and non-allergenic proteins in extracts of pollen from different origins by MS-based proteomics. Aqueous extracts prepared from commercially available Swedish birch pollen, pollen collected from Austrian trees and a commercial skin prick extract were analyzed by 1-DE, 2-DE, immunoblotting and mass spectrometry, resulting in a complete inventory of extractable, disease-relevant pollen proteins. A main focus of this study was on the isoform distribution of Bet v 1, the major allergen of birch pollen. Using a combination of intact mass determination and peptide sequencing, five isoforms (a, b, d, f and j) were unequivocally identified in Swedish and Austrian birch pollen extracts, while the skin prick extract contained only isoforms a, b and d. Using the same methods as for Bet v 1, divergencies in the sequence of birch profilin (Bet v 2), a plant panallergen, were solved. The molecular characterization of pollen extracts is relevant for standardization and development of new reagents for specific immunotherapy.

  8. The Puzzling Origin of the Acquaintance between Charlotte Lennox and Thomas Birch

    Directory of Open Access Journals (Sweden)

    Patricia L. Hamilton

    2015-03-01

    Full Text Available Scholars have puzzled over the origin of the relationship between Charlotte Lennox and Thomas Birch. That the two shared a cordial professional relationship in 1759 is not surprising, but it is unclear how and when Birch obtained the poem "The Dream, an ode by Miss Ramsey of 15" (ca. 1744-45 for his manuscript collection. Possibly Edward Cave, publisher of The Gentleman’s Magazine, or other professional associates such as Samuel Johnson or Samuel Richardson supplied it. But archival evidence indicates that Lady Isabella Finch, Lennox’s earliest patroness, was in contact with Birch in 1749, raising the question of whether she could have given Birch the poem. However, a different type of connection between Lennox and Birch is suggested by Lennox’s first novel, The Life of Harriot Stuart, written by Herself (1750, which mentions William Chillingworth, Isaac Barrow, and John Tillotson as theological influences. Lennox may have known of these three seventeenth-century divines through Birch’s biographical work on them.

  9. Expression of Aeromonas punctata ME-1 exo-xylanase X in E. coli for efficient hydrolysis of xylan to xylose.

    Science.gov (United States)

    Juturu, Veeresh; Teh, Tong Mei; Wu, Jin Chuan

    2014-12-01

    exo-Xylanase X from Aeromonas punctata ME-1 was functionally expressed in Escherichia coli with a carboxy terminal His tag (6×) and a molecular mass of 39.42 kDa, which is in agreement with the prediction from its amino acid composition. The recombinant exo-xylanase reached 186 mg l(-1) after induction by isopropyl β-D-1-thiogalactopyranoside. Its optimal temperature and pH were 50 °C and 6, respectively. The enzyme showed not only an exo-xylanase activity with K m of 3.90 mg ml(-1) and V max of 12.9 U μg(-1) for hydrolysis of Remazol Brilliant Blue-xylan but also a considerable exo-glucanase activity (27.9 U mg(-1)) on P-nitrophenyl β-D-cellobioside. It hydrolyzed xylan predominantly to xylobiose, xylotriose, xylotetraose, and xylose. An enzyme mixture of exo-xylanase and endo-xylanase (50 μg ml(-1) each) yielded a larger amount (330 mg l(-1)) of xylose from beechwood xylan than the controls (270 and 150 mg l(-1)) using them alone at 100 μg ml(-1), indicating a synergistic action between the two xylanases favoring the hydrolysis of beechwood xylan to release more xylose.

  10. Highly effective adsorption of heavy metal ions from aqueous solutions by macroporous xylan-rich hemicelluloses-based hydrogel.

    Science.gov (United States)

    Peng, Xin-Wen; Zhong, Lin-Xin; Ren, Jun-Li; Sun, Run-Cang

    2012-04-18

    Xylan-rich hemicelluloses-based hydrogel was developed as a novel porous bioadsorbent by graft co-polymerization of acrylic acid (AA) and xylan-rich hemicelluloses for adsorption of heavy metal ions (Pd(2+), Cd(2+), and Zn(2+)) from aqueous solutions. The chemical structure, the interaction between the hydrogel and metal ions, and the porous structure of xylan-rich hemicelluloses-g-AA hydrogel were revealed by Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of AA and cross-linker dosage, pH value, contacting time, and initial concentration of metal ion on the adsorption capacity were studied. The adsorption equilibrium time was about 60 min from the adsorption kinetics study. The maximum adsorption capacities of Pd(2+), Cd(2+), and Zn(2+) were 859, 495, and 274 mg/g, respectively. Furthermore, xylan-rich hemicelluloses-g-AA hydrogel also exhibited highly efficient regeneration and metal ion recovery efficiency and can be reused without noticeable loss of adsorption capacity for Pd(2+), Cd(2+), and Zn(2+) after quite a number of repeated adsorption/desorption cycles.

  11. Deconstruction of lignin linked p-coumarates, ferulates and xylan by NaOH enhances the enzymatic conversion of glucan

    NARCIS (Netherlands)

    Murciano Martínez, Patricia; Punt, Arjen M.; Kabel, Mirjam A.; Gruppen, Harry

    2016-01-01

    Thermo-assisted NaOH pretreatment to deconstruct xylan and lignin in sugar cane bagasse (SCB) is poorly understood. Hence, in this research it is was aimed to study the effect of NaOH pretreatment on the insoluble remaining lignin structures. Hereto, SCB milled fibres were pretreated using differ

  12. Deconstruction of lignin linked p-coumarates, ferulates and xylan by NaOH enhances the enzymatic conversion of glucan.

    Science.gov (United States)

    Murciano Martínez, Patricia; Punt, Arjen M; Kabel, Mirjam A; Gruppen, Harry

    2016-09-01

    Thermo-assisted NaOH pretreatment to deconstruct xylan and lignin in sugar cane bagasse (SCB) is poorly understood. Hence, in this research it is was aimed to study the effect of NaOH pretreatment on the insoluble remaining lignin structures. Hereto, SCB milled fibres were pretreated using different dosages of NaOH at different temperatures and residence times. Of untreated SCB about 63% of the lignin compounds were assigned as p-coumarates and ferulates, analysed by pyrolysis-GC/MS as 4-vinyl phenol and 4-vinyl guaiacol, and designated as non-core lignin (NCL) compounds. More severe NaOH pretreatments resulted in lower xylan and lower lignin recoveries in the insoluble residues. Especially, the relative abundance of NCL decreased and this decrease followed a linear trend with the decrease in xylan. Core lignin compounds, analysed as phenol, guaiacol and syringol, accumulated in the residues. The decrease in residual xylan and NCL correlated positively with the enzymatic hydrolysis of the residual glucan.

  13. Effect of pretreatment severity on xylan solubility and enzymatic breakdown of the remaining cellulose from wheat straw

    NARCIS (Netherlands)

    Kabel, M.A.; Bos, G.; Zeevalking, J.; Voragen, A.G.J.; Schols, H.A.

    2007-01-01

    The effect of process conditions used for wheat straw pretreatments on the liquor- and residue-composition was studied. Hereto, the pretreatment conditions were expressed in a `combined severity -factor¿. The higher the combined severity factor () the more xylan was released from the wheat straw, bu

  14. Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov., Psychrotolerant, Xylan-Degrading, Bacteria from Alaskan Tundra

    Science.gov (United States)

    Psychrotolerant, xylan-degrading, strains of bacteria were isolated from soil beneath moist non-acidic and acidic tundra in northern Alaska. Phylogenetic analysis based on 16S rRNA gene sequences revealed that each strain belonged to the genus Paenibacillus. The highest levels of 16S rRNA gene sim...

  15. Implications of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone for Water Use in Stands of Trembling Aspen and Paper Birch

    Science.gov (United States)

    Rhea, Lee Kirk

    Projected increases in the atmospheric concentration of CO2 and tropospheric O3 over the next 50 years are of concern due in part to their potential to affect forest water budgets. I conducted a series of studies at the Aspen Free Air CO2 and O3 Enrichment experiment near Rhinelander, WI to determine the effect of projected concentrations of these gases for the year 2050 on the water budget in stands of trembling aspen and paper birch. In order to determine the effects of elevated CO2 (eCO 2) and O3 (eO3) on rainfall partitioning between interception, through fall, and stem flow I performed a computerized analysis of photographed canopy branches and compared the results to hydrologic measurements. Elevated O3 significantly decreased total aspen and birch branch length, resulting in net decreases for 2002 whorls of -18 % and 2006 whorls of -16 %. Some of these changes had measurable effects on rainfall partitioning. The biomass of fine roots has been observed to change in response to eCO2 and eO3 at shallow depths, but little work has been done to assess deeper roots. I characterized fine root responses to eCO 2 and eO3 to a depth of one meter. Fumigation with O 3 increased small root biomass in shallow soil 30 % in all aspen plots and decreased root biomass in shallow soil 46 % in aspen-birch plots. Increases in root length up to 131 % and specific root length up to 77 % occurred under eO3 in middle and deep soil layers, indicating more extensive soil exploration at depth. Small root biomass in shallow soils increased 20 % to 24 % under eCO2, indicative of more intensive soil exploration near the surface. Previous studies of sapwood from Aspen-FACE indicated that anatomical structures related to hydraulic conductance (K) differed between aspen clones and that they responded to the treatments differently. I constructed embolism curves for stem wood samples collected below the base of the live crowns. There were no significant treatment effects on K at full water

  16. Simultaneous determination of betulin and betulinic acid in white birch bark using RP-HPLC.

    Science.gov (United States)

    Zhao, Guoling; Yan, Weidong; Cao, Dan

    2007-02-19

    A simple procedure is described for the simultaneous extraction and determination of betulin and betulinic acid in white birch bark. The extraction was checked using different solvents: dichloromethane, ethyl acetate, acetone, chloroform, methanol and 95% ethanol (aqueous solution, v/v). It was found 95% ethanol was a good extraction solvent that allowed extraction of triterpenoid with a highest content. Separation was achieved on a reversed phase C(18) column with acetonitrile-water 86:14 (v/v). Detection was accomplished with UV detection at lambda=210 nm. Using this method, the bioactive triterpenoid in white birch bark were simultaneously determined. Significant variations in the content of betulin and betulinic acid in white birch bark growing in different locations of China were also observed.

  17. DNA extraction of birch leaves by improved CTAB method and optimization of its ISSR system

    Institute of Scientific and Technical Information of China (English)

    PAN hua; YANG Chuan-ping; WEI Zhi-gang; JIANG Jing

    2006-01-01

    The basic method of DNA extraction (CTAB) was improved as the multi-times STE-CTAB extraction method and used to extract the DNA of birch leaved in this experiment. Results showed that the improved method is suitable not only for genomic DNA extraction of birch but also for that of other plants. The purity of genomic DNA extracted by the multi-times STE-CTAB extraction method is higher than that by one time STE-CTAB method, and it does not need the process of RNase. The factors of influencing ISSR system were explored based on the genomic DNA of birch extracted by the two methods. The optimal conditions for ISSR system were determined as follows: cycles of denaturation for 30 s at 94℃, annealing for 30 s at 51 ℃, extension for 30 s at 72℃, and a final 7 min extension at 72 ℃.

  18. Cord Wood Testing in a Non-Catalytic Wood Stove

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, G. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-06-30

    EPA Method 28 and the current wood stove regulations have been in-place since 1988. Recently, EPA proposed an update to the existing NSPS for wood stove regulations which includes a plan to transition from the current crib wood fuel to cord wood fuel for certification testing. Cord wood is seen as generally more representative of field conditions while the crib wood is seen as more repeatable. In any change of certification test fuel, there are questions about the impact on measured results and the correlation between tests with the two different fuels. The purpose of the work reported here is to provide data on the performance of a noncatalytic stove with cord wood. The stove selected has previously been certified with crib wood which provides a basis for comparison with cord wood. Overall, particulate emissions were found to be considerably higher with cord wood.

  19. Lipid transfer protein-linked hazelnut allergy in children from a non-Mediterranean birch-endemic area

    NARCIS (Netherlands)

    Flinterman, Annebeth E.; Akkerdaas, Jaap H.; Jager, Constance F. den Hartog; Rigby, Neil M.; Fernandez-Rivas, Montserrat; Hoekstra, Maarten O.; Bruijnzeel-Koomen, Carla A.; Knuist, Andr C.; van Ree, Ronald; Pasmans, Suzanne G.

    2008-01-01

    Background: Hazelnut allergy in birch pollen-exposed areas is usually due to cross-reactivity (Cor a 1 and 2) and is usually mild in nature (oral allergy). In areas without birches, severe reactions are more prevalent and linked to sensitization to the lipid transfer protein (LTP) Cor a 8. Objective

  20. Characterization of PR-10 genes from eight Betula species and detection of Bet v 1 isoforms in birch pollen

    NARCIS (Netherlands)

    Schenk, M.F.; Cordewener, J.H.G.; America, A.H.P.; Westende, van 't W.P.C.; Smulders, M.J.M.; Gilissen, L.J.W.J.

    2009-01-01

    Background - Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch (Betula pendula) have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the

  1. 低木聚糖含量的纸浆对湿部化学和纸张性能的影响(中试研究)%Effect of reduced pulp xylan content on wet end chemistry and paper properties - a pilot scale study

    Institute of Scientific and Technical Information of China (English)

    熊皇伟; 惠岚峰

    2015-01-01

    In this scale-up study, we examined the effects of using varying amounts of ifbers with reduced xylan content in paper. Bleached birch kraft pulp was partially or fully replaced by alkali-extracted pulp, and the effects of this replacement on the wet end chemistry of the paper machine and the resulting paper properties were determined. Our results show that paper properties can be maintained or improved when optimizing the partial replacement of bleached birch kraft pulp with alkali-extracted pulp. The incorporation of alkali-extracted pulp in paper machine stock had a positive effect on first pass retention and retention of chemicals. However, careful optimization of chemical dosages is required because of the altered charge balance in the wet end. The results of this study can be applied to predict the implications of varying pulp xylan content on the wet end chemistry of the paper machine and the resulting paper properties.%在此次中试研究中,确定了木聚糖含量低的纤维用量对纸张性能的影响。用碱抽提浆代替部分或全部漂白桦木硫酸盐浆,能够得到其对纸机湿部化学和最终纸张性能的影响。结果表明,用碱抽提浆代替部分漂白桦木硫酸盐浆可以保持甚至优化纸张性能。在纸机上网浆料中配入一定量的碱抽提浆,有利于一次留着和化学品的留着。然而,由于湿部电荷平衡的变化,因此对化学品用量的精心优化是必要的。本次研究的结果可用于预测不同木聚糖含量的纸浆,对纸机湿部化学和最终纸张性能的影响。

  2. Climate change effect on Betula (birch) and Quercus (oak) pollen seasons in the United States

    Science.gov (United States)

    Zhang, Yong; Bielory, Leonard; Georgopoulos, Panos G.

    2014-07-01

    Climatic change is expected to affect the spatiotemporal patterns of airborne allergenic pollen, which has been found to act synergistically with common air pollutants, such as ozone, to cause allergic airway disease (AAD). Observed airborne pollen data from six stations from 1994 to 2011 at Fargo (North Dakota), College Station (Texas), Omaha (Nebraska), Pleasanton (California), Cherry Hill and Newark (New Jersey) in the US were studied to examine climate change effects on trends of annual mean and peak value of daily concentrations, annual production, season start, and season length of Betula (birch) and Quercus (oak) pollen. The growing degree hour (GDH) model was used to establish a relationship between start/end dates and differential temperature sums using observed hourly temperatures from surrounding meteorology stations. Optimum GDH models were then combined with meteorological information from the Weather Research and Forecasting (WRF) model, and land use land coverage data from the Biogenic Emissions Land use Database, version 3.1 (BELD3.1), to simulate start dates and season lengths of birch and oak pollen for both past and future years across the contiguous US (CONUS). For most of the studied stations, comparison of mean pollen indices between the periods of 1994-2000 and 2001-2011 showed that birch and oak trees were observed to flower 1-2 weeks earlier; annual mean and peak value of daily pollen concentrations tended to increase by 13.6 %-248 %. The observed pollen season lengths varied for birch and for oak across the different monitoring stations. Optimum initial date, base temperature, and threshold GDH for start date was found to be 1 March, 8 °C, and 1,879 h, respectively, for birch; 1 March, 5 °C, and 4,760 h, respectively, for oak. Simulation results indicated that responses of birch and oak pollen seasons to climate change are expected to vary for different regions.

  3. Climate change effect on Betula (birch) and Quercus (oak) pollen seasons in the United States.

    Science.gov (United States)

    Zhang, Yong; Bielory, Leonard; Georgopoulos, Panos G

    2014-07-01

    Climatic change is expected to affect the spatiotemporal patterns of airborne allergenic pollen, which has been found to act synergistically with common air pollutants, such as ozone, to cause allergic airway disease (AAD). Observed airborne pollen data from six stations from 1994 to 2011 at Fargo (North Dakota), College Station (Texas), Omaha (Nebraska), Pleasanton (California), Cherry Hill and Newark (New Jersey) in the US were studied to examine climate change effects on trends of annual mean and peak value of daily concentrations, annual production, season start, and season length of Betula (birch) and Quercus (oak) pollen. The growing degree hour (GDH) model was used to establish a relationship between start/end dates and differential temperature sums using observed hourly temperatures from surrounding meteorology stations. Optimum GDH models were then combined with meteorological information from the Weather Research and Forecasting (WRF) model, and land use land coverage data from the Biogenic Emissions Land use Database, version 3.1 (BELD3.1), to simulate start dates and season lengths of birch and oak pollen for both past and future years across the contiguous US (CONUS). For most of the studied stations, comparison of mean pollen indices between the periods of 1994-2000 and 2001-2011 showed that birch and oak trees were observed to flower 1-2 weeks earlier; annual mean and peak value of daily pollen concentrations tended to increase by 13.6%-248%. The observed pollen season lengths varied for birch and for oak across the different monitoring stations. Optimum initial date, base temperature, and threshold GDH for start date was found to be 1 March, 8 °C, and 1,879 h, respectively, for birch; 1 March, 5 °C, and 4,760 h, respectively, for oak. Simulation results indicated that responses of birch and oak pollen seasons to climate change are expected to vary for different regions.

  4. Extrusion of xylans extracted from corn cobs into biodegradable polymeric materials.

    Science.gov (United States)

    Bahcegul, Erinc; Akinalan, Busra; Toraman, Hilal E; Erdemir, Duygu; Ozkan, Necati; Bakir, Ufuk

    2013-12-01

    Solvent casting technique, which comprises multiple energy demanding steps including the dissolution of a polymer in a solvent followed by the evaporation of the solvent from the polymer solution, is currently the main technique for the production of xylan based polymeric materials. The present study shows that sufficient water content renders arabinoglucuronoxylan (AGX) polymers extrudable, enabling the production of AGX based polymeric materials in a single step via extrusion, which is economically advantageous to solvent casting process for mass production. AGX polymers with water content of 27% were found to yield extrudates at an extrusion temperature of 90°C. The extruded strips showed very good mechanical properties with an ultimate tensile strength of 76 ± 6 MPa and elongation at break value of 35 ± 8%, which were superior to the mechanical properties of the strips obtained from polylactic acid.

  5. Thermal modelling of the high temperature treatment of wood based on Luikov's approach

    Energy Technology Data Exchange (ETDEWEB)

    Younsi, R.; Kocaefe, D.; Poncsak, S.; Kocaefe, Y. [University of Quebec, Chicoutimi (Canada). Dept. of Applied Sciences

    2005-07-01

    A 3D, unsteady-state mathematical model was used to simulate the behaviour of wood during high temperature treatment. The model is based on Luikov's approach and solves a set of coupled heat and mass transfer equations. Using the model, the temperature and moisture content profiles of wood were predicted as a function of time for different heating rates. Parallel to the modelling study, an experimental study was carried out using small birch samples. The samples were subjected to high temperature treatment in a thermogravimetric system under different operating conditions. The experimental results and the model predictions were found to be in good agreement. The results show that the distributions of temperature and moisture content are influenced appreciably by the heating rate and the initial moisture content. (author)

  6. Welding of solid wood

    OpenAIRE

    Ivica Župčić; Goran Mihulja; Andrija Bogner; Ivica Grbac; Ivica @up~i}, Goran Mihulja, Andrija Bogner, Ivica Grbac,; Božidar Hrovat

    2008-01-01

    This paper presents the up-to-date knowledge and results of the application of wood welding techniques at the Faculty of Forestry University of Zagreb. Wood welding technologies have been developed as a new way of bonding timber by using high temperature generatedby friction and pressure. Timber is assembled without any adhesives. During the process the surface layer of timber (lignin), which is in direct contact with its counterpart, melts due to high pressure and temperature, which is usual...

  7. Effect of Heat Treatment on Sorption Properties and Dimensional Stability of Wood

    Directory of Open Access Journals (Sweden)

    Povilas NAVICKAS

    2013-09-01

    Full Text Available This research was performed in order to determine how the heating process affects sorption properties and dimensional and shape stability of oak, lime and birch wood. By subjecting specimens to 3 hours heating at 130, 160, 190 and 220 ºC temperatures, a decrease in volume, density and mass was observed in proportion to the applied temperature. It was established that when oak wood specimens underwent heating at 220 ºC temperature, the decline of mass was 1.2 times higher than in the case of birch specimens. Both heated and unheated specimens underwent moistening in air at 25 ºC ±1 ºC temperature for 3 weeks with relative humidity being 85 % ±1 % and were soaked in water at room temperature for 4 hours. It was found that after applying high temperature heating, specimens absorbed smaller amounts of moisture. It was demonstrated that during the soaking process, the volume of unheated specimens was 3 times higher than in the case of specimens heated at 220 ºC temperature. The change in the volume of unheated oak was 1.27 times smaller than in the case of lime specimens and 1.16 times larger than in the case of birch specimens, which underwent heating at 220 ºC temperature. In addition, specimens that were exposed to heat had more stable measurements and shapes. It was noticed that the heating process caused significant changes in moisture and dimensional stability of specimens, when higher temperatures ranging from 190 ºC to 220 ºC were used. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5239

  8. Bio energy production in birch and hybrid aspen after addition of residue based fertilizers - establishment of fertilization trials; Bioenergiproduktion hos bjoerk och hybridasp vid tillfoersel av restproduktbaserade goedselmedel - etablering av goedslingsfoersoek

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar (EkoBalans Fenix AB, Malmoe (Sweden))

    2009-03-15

    Sewage sludge and wood ashes could be used as fertilizers in order to increase forest tree production. In southern Sweden forest growth normally increases with approximately 10 % after ash recycling due to increased N and/or P availability. P is added with the ashes and the pH-increasing effect of the wood ash can lead to increased N net mineralization. Other positive effects of wood ash recycling are improved nutrient sustainability and less acid run-off water. Possible negative effects are heavy metal accumulation, if the content of one or more heavy metals of the recycled ash exceeds the heavy metal content of the harvested biomass, and nitrate leaching if the vegetation cannot take up nitrified N. It is important to evaluate the sustainability of fertilization systems based on residues such as sludge and wood ash. Wood ash does not contain N and the P concentration often is too low for the ashes to function as an NP fertilizer. Thus N and sometimes P must be added. Sludge is an interesting alternative. The main purpose of the project is to study sustainable production of forest bio energy in intensively cultivated birch and hybrid aspen stands. Another purpose is to establish experiments that can be used for long term studies and as demonstration objects. In the first few years the goal is to study the short term effects of residue based fertilization compared to conventional NPK fertilization on tree nutrient uptake, nutrient leaching, sustainability and economy. In the long term the goal is to design appropriate fertilization strategies in a residue based fertilization system for the intensive cultivation of birch and hybrid aspen without negative side effects such as large scale nutrient leaching. Four field experiments were established in 2008 and one additional experiment in hybrid aspen will be established in the spring of 2009. Elevated bud N and P concentrations after fertilization with both Ashes+N and NPK means good possibilities for future growth

  9. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide.

    Science.gov (United States)

    Darbah, Joseph N T; Sharkey, Thomas D; Calfapietra, Carlo; Karnosky, David F

    2010-04-01

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO(2) and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO(2) protected photosynthesis of both species against moderate heat stress. Elevated CO(2) increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 degrees C) decreased all of these parameters in birch regardless of CO(2) treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO(2) were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO(2). Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms.

  10. Carbon and Nitrogen Transformations in Surface Soils Under Ermans Birch and Dark Coniferous Forests

    Institute of Scientific and Technical Information of China (English)

    DENG Xiao-Wen; HAN Shi-Jie; HU Yan-Ling; ZHOU Yu-Mei

    2009-01-01

    Soil samples were taken from an Ermans birch (Betula ermanii)-dark coniferous forest (Picea jezoensis and Abies nephrolepis) ecotone growing on volcanic ejecta in the northern slopc of Changbai Mountains of Northeast China,to compare soil carbon (C) and nitrogen (N) transformations in the two forests.The soil type is Umbri-Gelic Cambosols in Chinese Soil Taxonomy.Soil samples were incubated aerobically at 20 ℃ and field capacity of 700 g kg-1 over a period of 27 weeks.The amount of soil microbial biomass and net N mineralization were higher in the Ermans birch than the dark coniferous forest (P<0.05),whereas the cumulative C mineralization (as CO2 emission) in the dark coniferous forest exceeded that in the Ermans birch (P<0.05).Release of the cumulative dissolved organic C and dissolved organic N were greater in the Ermans birch than the dark coniferous forest (P<0.05).The results suggested that differences of forest types could result in considerable change in soil C and N transformations.

  11. Study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation

    Directory of Open Access Journals (Sweden)

    Dehelean Cristina A

    2012-11-01

    Full Text Available Abstract Background Pentacyclic triterpenes, mainly betulin and betulinic acid, are valuable anticancer agents found in the bark of birch tree. This study evaluates birch bark extracts for the active principles composition. Results New improved extraction methods were applied on the bark of Betula pendula in order to reach the maximum content in active principles. Extracts were analyzed by HPLC-MS, Raman, SERS and 13C NMR spectroscopy which revealed a very high yield of betulin (over 90%. Growth inhibiting effects were measured in vitro on four malignant human cell lines: A431 (skin epidermoid carcinoma, A2780 (ovarian carcinoma, HeLa (cervix adenocarcinoma and MCF7 (breast adenocarcinoma, by means of MTT assay. All of the prepared bark extracts exerted a pronounced antiproliferative effect against human cancer cell lines. In vivo studies involved the anti-inflammatory effect of birch extracts on TPA-induced model of inflammation in mice. Conclusions The research revealed the efficacy of the extraction procedures as well as the antiproliferative and anti-inflammatory effects of birch extracts.

  12. Mapping the birch and grass pollen seasons in the UK using satellite sensor time-series.

    Science.gov (United States)

    Khwarahm, Nabaz R; Dash, Jadunandan; Skjøth, C A; Newnham, R M; Adams-Groom, B; Head, K; Caulton, Eric; Atkinson, Peter M

    2017-02-01

    Grass and birch pollen are two major causes of seasonal allergic rhinitis (hay fever) in the UK and parts of Europe affecting around 15-20% of the population. Current prediction of these allergens in the UK is based on (i) measurements of pollen concentrations at a limited number of monitoring stations across the country and (ii) general information about the phenological status of the vegetation. Thus, the current prediction methodology provides information at a coarse spatial resolution only. Most station-based approaches take into account only local observations of flowering, while only a small number of approaches take into account remote observations of land surface phenology. The systematic gathering of detailed information about vegetation status nationwide would therefore be of great potential utility. In particular, there exists an opportunity to use remote sensing to estimate phenological variables that are related to the flowering phenophase and, thus, pollen release. In turn, these estimates can be used to predict pollen release at a fine spatial resolution. In this study, time-series of MERIS Terrestrial Chlorophyll Index (MTCI) data were used to predict two key phenological variables: the start of season and peak of season. A technique was then developed to estimate the flowering phenophase of birch and grass from the MTCI time-series. For birch, the timing of flowering was defined as the time after the start of the growing season when the MTCI value reached 25% of the maximum. Similarly, for grass this was defined as the time when the MTCI value reached 75% of the maximum. The predicted pollen release dates were validated with data from nine pollen monitoring stations in the UK. For both birch and grass, we obtained large positive correlations between the MTCI-derived start of pollen season and the start of the pollen season defined using station data, with a slightly larger correlation observed for birch than for grass. The technique was applied to

  13. Wood for the trees

    Directory of Open Access Journals (Sweden)

    Rob Garbutt

    2013-10-01

    Full Text Available Our paper focuses on the materiality, cultural history and cultural relations of selected artworks in the exhibition Wood for the trees (Lismore Regional Gallery, New South Wales, Australia, 10 June – 17 July 2011. The title of the exhibition, intentionally misreading the aphorism “Can’t see the wood for the trees”, by reading the wood for the resource rather than the collective wood[s], implies conservation, preservation, and the need for sustaining the originating resource. These ideas have particular resonance on the NSW far north coast, a region once rich in rainforest. While the Indigenous population had sustainable practices of forest and land management, the colonists deployed felling and harvesting in order to convert the value of the local, abundant rainforest trees into high-value timber. By the late twentieth century, however, a new wave of settlers launched a protest movements against the proposed logging of remnant rainforest at Terania Creek and elsewhere in the region. Wood for the trees, curated by Gallery Director Brett Adlington, plays on this dynamic relationship between wood, trees and people. We discuss the way selected artworks give expression to the themes or concepts of productive labour, nature and culture, conservation and sustainability, and memory. The artworks include Watjinbuy Marrawilil’s (1980 Carved ancestral figure ceremonial pole, Elizabeth Stops’ (2009/10 Explorations into colonisation, Hossein Valamanesh’s (2008 Memory stick, and AñA Wojak’s (2008 Unread book (in a forgotten language. Our art writing on the works, a practice informed by Bal (2002, Muecke (2008 and Papastergiadis (2004, becomes a conversation between the works and the themes or concepts. As a form of material excess of the most productive kind (Grosz, 2008, p. 7, art seeds a response to that which is in the air waiting to be said of the past, present and future.

  14. Allergens from birch pollen and pollen of the European chestnut share common epitopes.

    Science.gov (United States)

    Hirschwehr, R; Jäger, S; Horak, F; Ferreira, F; Valenta, R; Ebner, C; Kraft, D; Scheiner, O

    1993-09-01

    Type I allergy to pollen of the European chestnut (Castanea sativa) represents a major cause of pollinosis in (sub) Mediterranean areas. Using sera from 14 patients with established allergy to pollen of the European chestnut, 13/14 sera (92%) showed IgE-binding to a 22 kD protein, 2/14 (14%) displayed additional binding to a 14 kD protein and 1/14 (7%) bound only to the 14 kD protein of European chestnut pollen extract. Two monoclonal mouse antibodies, BIP 1 and BIP 4, directed against different epitopes of Bet v I (the major birch pollen allergen), and a rabbit antibody to recombinant birch profilin (rBet v II) were used to characterize the proteins of the European chestnut pollen. The recombinant birch pollen allergens, rBet v I and rBet v II (profilin) were employed to show common allergenic structures on proteins from both birch and European chestnut pollen by IgE-inhibition experiments. Despite the fact that the 22 kD protein displayed a higher molecular weight in comparison to the 17 kD major birch pollen allergen, Bet v I, we could demonstrate reactivity of both monoclonal antibodies, BIP 1 and BIP 4, with this protein. A complete inhibiton of IgE-binding to this 22 kD protein was shown by pre-incubating sera with purified recombinant Bet v I. In addition, the 14 kD protein could be identified by IgE-inhibition studies with recombinant Bet v II and by using a rabbit anti-profilin antibody as the profilin from pollen of the European chestnut.

  15. Impacts of Elevated Atmospheric CO2 and O3 on Paper Birch (Betula papyrifera: Reproductive Fitness

    Directory of Open Access Journals (Sweden)

    Joseph N. T. Darbah

    2007-01-01

    Full Text Available Atmospheric CO2 and tropospheric O3 are rising in many regions of the world. Little is known about how these two commonly co-occurring gases will affect reproductive fitness of important forest tree species. Here, we report on the long-term effects of CO3 and O3 for paper birch seedlings exposed for nearly their entire life history at the Aspen FACE (Free Air Carbon Dioxide Enrichment site in Rhinelander, WI. Elevated CO2 increased both male and female flower production, while elevated O3 increased female flower production compared to trees in control rings. Interestingly, very little flowering has yet occurred in combined treatment. Elevated CO2 had significant positive effect on birch catkin size, weight, and germination success rate (elevated CO2 increased germination rate of birch by 110% compared to ambient CO2 concentrations, decreased seedling mortality by 73%, increased seed weight by 17%, increased root length by 59%, and root-to-shoot ratio was significantly decreased, all at 3 weeks after germination, while the opposite was true of elevated O3 (elevated O3 decreased the germination rate of birch by 62%, decreased seed weight by 25%, and increased root length by 15%. Under elevated CO2, plant dry mass increased by 9 and 78% at the end of 3 and 14 weeks, respectively. Also, the root and shoot lengths, as well as the biomass of the seedlings, were increased for seeds produced under elevated CO2, while the reverse was true for seedlings from seeds produced under the elevated O3. Similar trends in treatment differences were observed in seed characteristics, germination, and seedling development for seeds collected in both 2004 and 2005. Our results suggest that elevated CO2 and O3 can dramatically affect flowering, seed production, and seed quality of paper birch, affecting reproductive fitness of this species.

  16. Accuracy and functionality of hand held wood moisture content meters

    Energy Technology Data Exchange (ETDEWEB)

    Forsen, H.; Tarvainen, V. [VTT Building Technology, Espoo (Finland). Building Materials and Products, Wood Technology

    2000-09-01

    The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10%, 12 - 14% and 16 - 18%). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15% units/deg C which has to be considered when the moisture content of wood is measured at temperatures other than 20 deg C. The other properties of wood, such as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC

  17. CHEMICAL VALORIZATION OF AGRICULTURAL BY-PRODUCTS: ISOLATION AND CHARACTERIZATION OF XYLAN-BASED ANTIOXIDANTS FROM ALMOND SHELL BIOMASS

    Directory of Open Access Journals (Sweden)

    Anna Ebringerová

    2008-02-01

    Full Text Available The isolation of non-cellulosic polysaccharides from both almond shells and their solid residue after autohydrolysis using a two-step alkaline extraction without and in combination with short ultrasonic treatment was investigated. The obtained polysaccharide preparations were characterized by yield, chemical composition and structural features, and the antioxidant activity of the water-soluble preparations was discussed in relation to the content of phenolics. The results suggested that, depending on the extraction conditions used, xylan associated to various extent with pectic polysaccharides and phenolics can be prepared, and the reaction time significantly shortened by application of ultrasound. The xylan polymers might serve as biopolymer sources in native form or after targeted modification for production of value-added substances and polysaccharide-based antioxidants, applicable in food, cosmetics and other areas.

  18. Photodegradation of thermally modified wood.

    Science.gov (United States)

    Srinivas, Kavyashree; Pandey, Krishna K

    2012-12-01

    Natural wood, being biological material, undergoes rapid degradation by ultraviolet (UV) radiations and other environmental factors under outdoor exposure. In order to protect wood from such degradation, the chemical structure of wood is altered by chemical modification or heat treatment. In the present study, heat treated specimens of rubberwood (Hevea brasiliensis) were exposed to xenon light source in a weather-o-meter for different periods up to 300 h. Photostability of modified and unmodified wood was evaluated in terms of colour and chemical changes. Light coloured untreated wood became dark upon UV irradiation whereas, dark colour of heat treated wood lightened on UV exposure. CIE lightness parameter (L(*)) decreased for untreated wood whereas its value increased for heat treated wood upon irradiation. Other colour coordinates a(*) and b(*) increased with exposure duration for both untreated and heat treated wood. The overall colour change (ΔE(*)) increased for both untreated and heat treated wood. The Fourier Transform Infrared (FTIR) spectroscopic studies revealed severe lignin degradation of heat treated wood due to UV light exposure. Colour changes and FTIR measurements indicate that thermal modification of wood was ineffective in restricting light induced colour changes and photodegradation of wood polymers.

  19. The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts.

    Science.gov (United States)

    Déjean, Guillaume; Blanvillain-Baufumé, Servane; Boulanger, Alice; Darrasse, Armelle; Dugé de Bernonville, Thomas; Girard, Anne-Laure; Carrére, Sébastien; Jamet, Stevie; Zischek, Claudine; Lautier, Martine; Solé, Magali; Büttner, Daniela; Jacques, Marie-Agnès; Lauber, Emmanuelle; Arlat, Matthieu

    2013-05-01

    Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature. Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts.

  20. Precision wood particle feedstocks

    Science.gov (United States)

    Dooley, James H; Lanning, David N

    2013-07-30

    Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

  1. Fatigue Damage in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1996-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Fatigue failure is found to depend both on the total time under load and on the number of cycles.Recent accelerated fatigue research on wood is reviewed, and a discrepancy between...... failure explanation under fatigue and static load conditions is observed. In the present study small clear specimens of spruce are taken to failure in square wave formed fatigue loading at a stress excitation level corresponding to 80% of the short term strength. Four frequencies ranging from 0.01 Hz...... to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation between stiffness reduction...

  2. Facilitating the enzymatic saccharification of pulped bamboo residues by degrading the remained xylan and lignin-carbohydrates complexes.

    Science.gov (United States)

    Huang, Caoxing; He, Juan; Li, Xin; Min, Douyong; Yong, Qiang

    2015-09-01

    Kraft pulping was performed on bamboo residues and its impact on the chemical compositions and the enzymatic digestibility of the samples were investigated. To improve the digestibility of sample by degrading the xylan and lignin-carbohydrates complexes (LCCs), xylanase and α-L-arabinofuranosidase (AF) were supplemented with cellulase. The results showed more carbohydrates were remained in the samples pulped with low effective alkali (EA) charge, compared to conventional kraft pulping. When 120 IU/g xylanase and 15 IU/g AF were supplemented with 20 FPU/g cellulase, the xylan degradation yield of the sample pulped with 12% EA charge increased from 68.20% to 88.35%, resulting in an increased enzymatic saccharification efficiency from 58.98% to 83.23%. The amount of LCCs in this sample decreased from 8.63/100C9 to 2.99/100C9 after saccharification with these enzymes. The results indicated that degrading the remained xylan and LCCs in the pulp could improve its enzymatic digestibility.

  3. Direct fermentation of xylan by Clostridium strain BOH3 for the production of butanol and hydrogen using optimized culture medium.

    Science.gov (United States)

    Rajagopalan, Gobinath; He, Jianzhong; Yang, Kun Lin

    2014-02-01

    Clostridium strain BOH3 is able to utilize 10 g/l of xylan in reinforced clostridial medium (RCM) and produce butanol and hydrogen. However, increasing xylan concentration to 30 g/l does not enhance the production of butanol and hydrogen due to insufficient expression of xylanase enzyme (27.5 U/mg). To enhance the xylanase activity, an optimized culture medium (OCM), which consists of sugarcane bagasse hydrolysate (11.75 g/l), ammonium sulfate (8.92 g/l) and iron (III) chloride (1.45 mM) is designed. In the optimized OCM, Clostridium strain BOH3 expresses more xylanase and shows higher xylanase activity (44.05 ± 0.25 U/mg) in the OCM. This activity is about 1.6-fold higher than that in the original RCM. Employing OCM as a medium, Clostridium strain BOH3 effectively ferments high concentration (30 and 50 g/l) of xylan and produces 12.05 ± 0.15 and 14.80 ± 0.15 g/l of butanol and 1.78 ± 0.08 and 2.65 ± 0.15 l/l of hydrogen, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Development of strains of the thermotolerant yeast Hansenula polymorpha capable of alcoholic fermentation of starch and xylan.

    Science.gov (United States)

    Voronovsky, Andriy Y; Rohulya, Olha V; Abbas, Charles A; Sibirny, Andriy A

    2009-01-01

    The thermotolerant yeast Hansenula polymorpha ferments glucose and xylose to ethanol at high temperatures. However, H. polymorpha cannot utilize starchy materials or xylans. Heterologous amylolytic and xylanolytic enzymes have to be expressed in this yeast to provide for utilization and growth on starch and xylan. Genes SWA2 and GAM1 from the yeast Schwanniomyces occidentalis, encoding alpha-amylase and glucoamylase, respectively, were expressed in H. polymorpha. The expression was achieved by integration of the SWA2 and GAM1 genes under the strong constitutive promoter of the H. polymorpha glyceraldehyde-3-phosphate dehydrogenase gene (HpGAP) into H. polymorpha genome. Resulting transformants acquired the ability to grow on a minimal medium containing soluble starch as a sole carbon source. Ethanol production at high-temperature fermentation from starch by the recombinant strains was up to 10 g/L. The XYN2 gene encoding endoxylanase of the fungus Trichoderma reseei was expressed in H. polymorpha. Co-expression of xlnD gene coding for beta-xylosidase of the fungus Aspergillus niger and the XYN2 gene in H. polymorpha was achieved by integration of these genes under control of the HpGAP promoter. Resulting transformants were capable of growth and alcoholic fermentation on a minimal medium supplemented with birchwood xylan as a sole carbon source at 48 degrees C.

  5. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    Science.gov (United States)

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization.

  6. Methane from wood

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, T. F.; Barreto, L.; Kypreos, S.; Stucki, S

    2005-07-15

    The role of wood-based energy technologies in the Swiss energy system in the long-term is examined using the energy-system Swiss MARKAL model. The Swiss MARKAL model is a 'bottom-up' energy-systems optimization model that allows a detailed representation of energy technologies. The model has been developed as a joint effort between the Energy Economics Group (EEG) at Paul Scherrer Institute PSI) and the University of Geneva and is currently used at PSI-EEG. Using the Swiss MARKAL model, this study examines the conditions under which wood-based energy technologies could play a role in the Swiss energy system, the most attractive pathways for their use and the policy measures that could support them. Given the involvement of PSI in the ECOGAS project, especial emphasis is put on the production of bio-SNG from wood via gasification and methanation of syngas and on hydrothermal gasification of woody biomass. Of specific interest as weIl is the fraction of fuel used in passenger cars that could be produced by locally harvested wood. The report is organized as follows: Section 2 presents a brief description of the MARKAL model. Section 3 describes the results of the base case scenario, which represents a plausible, 'middle-of-the-road' development of the Swiss energy system. Section 4 discusses results illustrating the conditions under which the wood-based methanation technology could become competitive in the Swiss energy market, the role of oil and gas prices, subsidies to methanation technologies and the introduction of a competing technology, namely the wood-based Fischer-Tropsch synthesis. FinaIly, section 5 outlines some conclusions from this analysis. (author)

  7. Variation in root wood anatomy

    NARCIS (Netherlands)

    Cutler, D.F.

    1976-01-01

    Variability in the anatomy of root wood of selected specimens particularly Fraxinus excelsior L. and Acer pseudoplatanus L. in the Kew reference microscope slide collection is discussed in relation to generalised statements in the literature on root wood anatomy.

  8. Variation in root wood anatomy

    NARCIS (Netherlands)

    Cutler, D.F.

    1976-01-01

    Variability in the anatomy of root wood of selected specimens particularly Fraxinus excelsior L. and Acer pseudoplatanus L. in the Kew reference microscope slide collection is discussed in relation to generalised statements in the literature on root wood anatomy.

  9. TCP HolyWood

    OpenAIRE

    Oscar Núñez Mori

    2005-01-01

    We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard. Apresentamos um novo Protocolo de Controle de...

  10. False "highlighting" with Wood's lamp.

    Science.gov (United States)

    Silverberg, Jonathan I; Silverberg, Nanette B

    2014-01-01

    Wood's lamp evaluation is used to diagnose pigmentary disorders. For example, vitiligo typically demonstrates lesional enhancement under Wood's lamp evaluation. Numerous false positive enhancing lesions can be noted in the skin. We describe a 5-year-old Hispanic boy who had painted his face with highlighter, producing enhancing lesions under Wood's lamp. Physicians who use Wood's lamp should be aware that the appearance of markers and highlighter can mimic that of true clinical illnesses.

  11. Nutritional ecology of the formosan subterranean termite (Isoptera: Rhinotermitidae): feeding response to commercial wood species.

    Science.gov (United States)

    Morales-Ramos, J A; Rojas, M G

    2001-04-01

    The feeding preferences of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were tested in three separate experiments on 28 different wood species. Experiment 1 was a multiple-choice test designed to test relative preferences among 24 wood species commercially available in New Orleans, LA. Experiment 2 was a similar study designed to test relative preferences among 21 wood species shown or reported to be unpalatable to the Formosan subterranean termite. Experiment 3 was a no-choice test to examine the feeding deterrence of the 10 least preferred wood species. Preference was determined by consumption rates. Birch (Betula alleghaniensis Britton), red gum (Liquidambar styraciflua L.), Parana pine [Araucaria angustifolia (Bert.) 1, sugar maple (Acer saccharum Marsh.), pecan (Carya illinoensis Wangenh.), and northern red oak (Quercus rubra L.) were the most preferred species by C. formosanus in order of consumption rate. All of these species were significantly more preferred than southern yellow pine (Pinus taeda L.), widely used for monitoring. Sinker cypress [ = old growth bald cypress, Taxodium distichum (L.)], western red cedar (Thuja plicata Donn), Alaskan yellow cedar (Chamaecyparis nootkatensis D. Don), eastern red cedar (Juniperus virginiana L.), sassafras [Sassafras albidum (Nutt.)], Spanish cedar (Cedrella odorata L.), Honduras mahogany (Swietenia macrophyla King), Indian rosewood (Dalbergia latifolia Roxb.), Honduras rosewood (D. stevensonii Standl.), and morado (Machaerium sp.) induced significant feeding deterrence and mortality to C. formosanus. The last eight species produced 100% mortality after 3 mo.

  12. Fabrication of low-cost Mod-OA wood composite wind turbine blades

    Science.gov (United States)

    Lark, R. F.; Gougeon, M.; Thomas, G.; Zuteck, M.

    1983-02-01

    The wood composite blades were fabricated by using epoxy resin-bonded laminates of Douglas fir veneers for the leading edge spar sections and honeycomb-cored birch plywood panels for the blade trailing edge or afterbody sections. The blade was joined to the wind turbine hub assembly by epoxy resin-bonded steel load take-off studs. The wood composite blades were installed in the Mod-OA wind turbine test facility at Kahuku, Hawaii. The wood composite blades have successfully completed high power (average of 150 kW) operations for an eighteen month period (nearly 8,000 hr) before replacement with another set of wood composite blades. The original set of blades was taken out of service because of the failure of the shank on one stud. An inspection of the blades at NASA-Lewis showed that the shank failure was caused by a high stress concentration at a corrosion pit on the shank fillet radius which resulted in fatigue stresses in excess of the endurance limit.

  13. An arabino(glucurono)xylan isolated from immunomodulatory active hemicellulose fraction of Salvia officinalis L.

    Science.gov (United States)

    Capek, P; Matulová, M

    2013-08-01

    From the aerial parts of sage (Salvia officinalis L.) an arabino-(4-O-methyl-glucurono)-xylan (AGX) was isolated by alkaline extraction followed by precipitation with barium hydroxide solution. Polymer was isolated from sage as a light brown polysaccharide material of molecular mass (Mp) 84,000. Compositional analyses of sage AGX revealed xylose (81%), arabinose (10%), glucuronic acid (8%) and small amounts of hexoses (1%). Linkage sugar analyses showed the (1→4)-linked xylopyranosyl backbone with low degree of substitution (9-10%) at O-2 and O-3. Arabinofuranose residues were found as the terminal, 1,3-, 1,5- and 1,3,5-linked. NMR structural analyses of acidic oligomers, generated by partial acidic hydrolysis of AGX, confirmed a substitution of xylose residues by glucuronic acid and its 4-O-methyl derivate at O-2 at an average on every fourteenth xylose residue. NMR and FT-IR measurements, as well as a high negative optical rotation confirmed the β configuration of glycosidic linkages in AGX backbone.

  14. Microbacterium xylanilyticum sp. nov., a xylan-degrading bacterium isolated from a biofilm.

    Science.gov (United States)

    Kim, Kwang Kyu; Park, Hye Yoon; Park, Wooshin; Kim, In S; Lee, Sung-Taik

    2005-09-01

    A novel xylan-degrading bacterium, S3-E(T), was isolated from the biofilm of a membrane bioreactor. The cells of this strain were Gram-positive, non-motile, non-spore-forming rods, produced primary branches and formed yellow colonies on nutrient agar. The strain had chemotaxonomic markers that were consistent with classification in the genus Microbacterium, i.e. MK-12, MK-11 and MK-13 as the major menaquinones, predominant iso- and anteiso-branched cellular fatty acids, glucose and galactose as the cell-wall sugars, peptidoglycan-type B2beta with glycolyl residues and a DNA G+C content of 69.7 mol%. Phylogenetic analysis, based on 16S rRNA gene sequencing, showed that strain S3-E(T) is most similar to Microbacterium hominis IFO 15708(T) and Microbacterium foliorum DSM 12966(T) (97.6 and 97.4% sequence similarity, respectively), and that it forms a separate lineage with M. hominis in the genus Microbacterium. DNA-DNA hybridization results and phenotypic properties showed that strain S3-E(T) could be distinguished from all known Microbacterium species and represented a novel species, for which the name Microbacterium xylanilyticum sp. nov. is proposed; the type strain is S3-E(T) (=DSM 16914(T)=KCTC 19079(T)).

  15. O-feruloylated, O-acetylated oligosaccharides as side-chains of grass xylans.

    Science.gov (United States)

    Wende, G; Fry, S C

    1997-03-01

    Partial acid hydrolysis of cell wall material from Festuca arundinacea cell cultures yielded a novel O-feruloylated trisaccharide (3). Treatment of 3 with Driselase, which contains beta- but not alpha-D-xylosidase, released xylose plus the known compound, beta-D-xylopyranosyl-(1-->2)-(5-O-feruloyl)-L-arabinose. Since 3 contained one NaIO4-resistant xylose residue, it was concluded to be beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1--> 2)-(5-O-feruloyl)-L-arabinose. Partial acid hydrolysis of Festuca cell walls also yielded several higher-M(r) feruloylated oligosaccharides, including a feruloylated pentasaccharide, 4 (sugar composition: Ara + Xyl2 + two non-pentose residues) and a feruloylated heptasaccharide, 5 (Ara + Xyl3 + three non-pentose residues). Compounds 4 and 5 were endogenously O-acetylated but 3 was not. Similar or identical compounds were found in hydrolysates of 20 additional species of the Gramineae. These products represent a series of complex side-chains which, in vivo, are attached via Araf residues to the parent xylan. Their possible biological roles are discussed.

  16. Continuous propionic acid production with Propionibacterium acidipropionici immobilized in a novel xylan hydrogel matrix.

    Science.gov (United States)

    Wallenius, Janne; Pahimanolis, Nikolaos; Zoppe, Justin; Kilpeläinen, Petri; Master, Emma; Ilvesniemi, Hannu; Seppälä, Jukka; Eerikäinen, Tero; Ojamo, Heikki

    2015-12-01

    The cell immobilization potential of a novel xylan based disulfide-crosslinked hydrogel matrix reinforced with cellulose nanocrystals was studied with continuous cultivation of Propionibacterium acidipropionici using various dilution rates. The cells were immobilized to hydrogel beads suspended freely in the fermentation broth or else packed into a column connected to a stirred tank reactor. The maximum propionic acid productivity for the combined stirred tank and column was 0.88gL(-1)h(-1) and the maximum productivity for the column was determined to be 1.39gL(-1)h(-1). The maximum propionic acid titer for the combined system was 13.9gL(-1) with a dilution rate of 0.06h(-1). Dry cell density of 99.7gL(-1) was obtained within the column packed with hydrogel beads and productivity of 1.02gL(-1)h(-1) was maintained in the column even with the high circulation rate of 3.37h(-1).

  17. Development of SSR Markers and Genetic Diversity in White Birch (Betula platyphylla.

    Directory of Open Access Journals (Sweden)

    Wei Hao

    Full Text Available In order to study genetic diversity of white birch (Betula platyphylla, 544 primer pairs were designed based on the genome-wide Solexa sequences. Among them, 215 primer pairs showed polymorphism between five genotypes and 111 primer pairs that presented clear visible bands in genotyping 41 white birch plants that were collected from 6 different geographical regions. A total of 717 alleles were obtained at 111 loci with a range of 2 to 12 alleles per locus. The results of statistic analysis showed that polymorphic frequency of the alleles ranged from 17% to 100% with a mean of 55.85%; polymorphism information content (PIC of the loci was from 0.09 to 0.58 with a mean of 0.30; and gene diversity between the tested genotypes was from 0.01 to 0.66 with a mean of 0.36. The results also indicated that major allele frequency ranged from 0.39 to 1.00 with an mean of 0.75; expected heterozygosity from 0.22 to 0.54 with a mean of 0.46; observed heterozygosity from 0.02 to 0.95 with a mean of 0.26; Nei's index from 0.21 to 0.54 with a mean of 0.46; and Shannon's Information from 0.26 to 0.87 with a mean of 0.66. The 41 white birch genotypes at the 111 selected SSR loci showed low to moderate similarity (0.025-0.610, indicating complicated genetic diversity among the white birch collections. The UPGMA-based clustering analysis of the allelic constitution of 41 white birch genotypes at 111 SSR loci suggested that the six different geographical regions can be further separated into four clusters at a similarity coefficient of 0.22. Genotypes from Huanren and Liangshui provenances were grouped into Cluster I, genotypes from Xiaobeihu and Qingyuan provenances into Cluster II, genotypes from Finland provenance into Cluster III, and genotypes from Maoershan into Cluster IV. The information provided in this study could help for genetic improvement and germplasm conservation, evaluation and utilization in white birch tree breeding program.

  18. Wood dust exposure in wood industry and forestry.

    Science.gov (United States)

    Puntarić, Dinko; Kos, Ankica; Smit, Zdenko; Zecić, Zeljko; Sega, Kresimir; Beljo-Lucić, Ruzica; Horvat, Dubravko; Bosnir, Jasna

    2005-06-01

    The aim of the study was to determine occupational exposure in Croatian wood processing industry and forest workers to harmful effects of wood dust on the risk of nose, nasal cavity and lung carcinoma. Mass concentrations of respirable particles and total wood dust were measured at two wood processing plants, three woodwork shops, and one lumbering site, where 225 total wood dust samples and 221 respirable particle samples were collected. Wood dust mass concentration was determined by the gravimetric method. Mass concentrations exceeding total wood dust maximal allowed concentration (MAC, 3 mg/m3) were measured for beechwood and oakwood dust in 38% (79/206) of study samples from wood processing facilities (plants and woodwork shops). Mass concentrations of respirable particles exceeding MAC (1 mg/m3) were recorded in 24% (48/202) of samples from wood processing facilities (mean 2.38 +/- 2.08 mg/m3 in plants and 3.6 +/- 2.22 mg/m3 in woodwork shops). Thus, 13% (27/206) of work sites in wood processing facilities failed to meet health criteria according to European guidelines. Launching of measures to reduce wood dust emission to the work area is recommended.

  19. Some Exploitation Properties of Wood Plastic Hybrid Composites Based on Polypropylene and Plywood Production Waste

    Science.gov (United States)

    Kajaks, Janis; Kalnins, Karlis; Uzulis, Sandris; Matvejs, Juris

    2015-12-01

    During the last 20-30 years many researchers have paid attention to the studies of properties of thewood polymer composites (WPC). A lot of works are closely related to investigations of exploitation properties of wood fibres or wood flour containing polyolefine composites [1, 2]. The most useful from wide selection of polyolefines are polypropylenes, but timber industry waste materials comprising lignocellulose fibres are often used as reinforcement of WPC [3-12]. Plywood industry is not an exception - part of waste materials (by-products) are used for heat energy, i.e. burned. In this work we have approbated reinforcing of polypropylene (PP) with one of the plywood industry by-products, such as birch plywood sawdust (PSWD),which containswood fibre fractions with different length [13]. The main fraction (50%) includes fibres with length l = 0.5 - 1 mm. Our previous study [13] has confirmed that PSWD is a promising filler for PP reinforcing. Addition of PSWD up to 40-50 wt.% has increased WPC tensile and flexural modulus, but decreased deformation ability of PP matrix, impact strength, water resistance and fluidity of composite melts. It was shown [13] that modification of the composites with interfacial modifier - coupling agent maleated polypropylene (MAPP content up to 5-7 wt.%) considerably improved all the abovementioned properties. SEM investigations also confirmed positive action of coupling agent on strengthening of adhesion interaction between components wood and PP matrix. Another way how to make better properties of the WPC is to form hybridcomposites [1, 14-24]. Very popular WPC modifiers are nanoparticle additions like organonanoclays, which increase WPC physical-mechanical properties - microhardness, water resistance and diminish barrier properties and combustibility [1, 2, 14-17, 19, 20]. The goal of this study was to investigate organonanoclays influence on plywood production industry by-product birch plywood sawdust (PSWD) containing

  20. Grant Wood: "American Gothic."

    Science.gov (United States)

    Fitzgerald, Diane M.

    1988-01-01

    Presents a lesson plan which exposes students in grades 10-12 to the visual symbols and historical references contained in Grant Wood's "American Gothic." Includes background information on the artist and the painting, instructional strategies, a studio activity, and evaluation criteria. (GEA)

  1. Wood waste in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Matos, O.; Ribeiro, R. [Biomass Centre for Energy - CBE, Miranda do Corvo (Portugal)

    1997-12-31

    The energy policy of the EC, as well as most of member states points to a sizeable increase of energy production based on renewable energy sources, wood, wood residues, agricultural residues, energy crops including SRF, organic sludges, solid residues, etc. Most recent goals indicate a desirable duplication of today`s percentage by 2010. The reasons for this interest, besides diversification of sources, less dependence on imported fuels, use of endogenous resources, expected decrease of fossil fuel reserves, use of available land, additional employment and income for rural communities, etc., are related to important environmental benefits namely in terms of emissions of hot house gases. Wood waste, resulting from forest operations, cleaning, cultural and final cuttings, and from wood based industries, constitute a special important resource by reason of quality and availability. In addition to this they do not require additional land use and the removal is beneficial. In the run-up to the becoming December`s 1997 `Climate Change Summit` in Kioto, there is mounting pressure on companies to plan on carbon cuts. (author) 6 refs., 1 tab.

  2. Tannins in tropical woods

    Energy Technology Data Exchange (ETDEWEB)

    Doat, J.

    1978-01-01

    A preliminary study was made of the chemistry of pyrogallol- and catecholtannins, their general properties and methods of extraction and determination. Three methods of estimation - Lowenthal, powdered hide and spectrophotometry - were compared using two control solutions, four samples of wood and one of bark. Using the empirical powdered hide method, tannins of both types were estimated in wood and bark of various tropical species (some separately and some as a mixture), Moroccan oaks (Quercus suber and Q. ilex), and European oak 9Q. petraea). Further tests were made on the wood and bark of the two mangrove species, Rhizophora mangle and R. racemosa, by subjecting them to successive extraction with a range of solvents. None of the woods tested had as much as the 10% of tannins considered necessary in economic sources. The bark of the two mangroves, of Eucalyptus urophylla and of Prosopis africana had tannin contents over 10% and the latter two species had very favorable tannin/non-tannin ratios. All the tropical species, with the probable exception of E. urophylla, had only catecholtannins. Only the oaks and E. urophylla bark gave positive results when tested for gallotannins.

  3. Identification of coniferous woods

    Science.gov (United States)

    B. Francis Kukachka

    1960-01-01

    The identification of coniferous woods is generally regarded as being more difficult than for the hardwood species. This is due to the fact that conifers are more elemental in their structure and, as a consequence, the number of diagnostic features that may he employed is proportionately smaller. Instructions are given here in the sequential use of primary diagnostic...

  4. Partial transparency of compressed wood

    Science.gov (United States)

    Sugimoto, Hiroyuki; Sugimori, Masatoshi

    2016-05-01

    We have developed novel wood composite with optical transparency at arbitrary region. Pores in wood cells have a great variation in size. These pores expand the light path in the sample, because the refractive indexes differ between constituents of cell and air in lumen. In this study, wood compressed to close to lumen had optical transparency. Because the condition of the compression of wood needs the plastic deformation, wood was impregnated phenolic resin. The optimal condition for high transmission is compression ratio above 0.7.

  5. Cadmium accumulation and its effect on the in vitro growth of woody fleabane and mycorrhized white birch

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, R.; Bertrand, A.; Casares, A. [Departamento de Biologia de Organismos y Sistemas, Oviedo University, Catedratico Rodrigo Uria s/n, 33071 Oviedo (Spain); Garcia, R. [Departamento de Quimica Fisica y Analitica, Oviedo University, Julian Claveria s/n, 33071 Oviedo (Spain); Gonzalez, A. [Departamento de Biologia de Organismos y Sistemas, Oviedo University, Catedratico Rodrigo Uria s/n, 33071 Oviedo (Spain)], E-mail: aidag@uniovi.es; Tames, R.S. [Departamento de Biologia de Organismos y Sistemas, Oviedo University, Catedratico Rodrigo Uria s/n, 33071 Oviedo (Spain)

    2008-04-15

    The effect of Cd on woody fleabane (Dittrichia viscosa (L.) Greuter) and white birch (Betula celtiberica Rothm. and Vasc.) was examined. Woody fleabane and white birch were grown in vitro in Murashige, T., Skoog, F., [1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473-479] (MS) plus Cd (10 mg Cd kg{sup -1}) and except for root length in white birch, plant development was inhibited when Cd was added. Cd accumulation in above-ground tissues showed differences among clones, reaching 1300 and 463 mg Cd kg{sup -1} dry wt. in selected clones of woody fleabane and white birch, respectively. Tolerance of Paxillus filamentosus (Scop) Fr. to Cd was also examined before mycorrhization. Plants of mycorrhized white birch grown in the presence of Cd had a better development and accumulated more Cd in their shoots than the non-mycorrhized ones. The use of selected clones of woody fleabane and the mycorrhization of white birch enhance extraction efficiency from contaminated soils in phytoremediation programs. - The high accumulation of Cd observed in selected clones of Dittrichia viscosa and mycorrhized Betula celtiberica grown in vitro implies a potential application for phytoextraction.

  6. Effect of steam treatment on the properties of wood cell walls.

    Science.gov (United States)

    Yin, Yafang; Berglund, Lars; Salmén, Lennart

    2011-01-10

    Steam treatment is a hygrothermal method of potential industrial significance for improving the dimensional stability and durability of wood materials. The steaming results in different chemical and micromechanical changes in the nanostructured biocomposite that comprise a wood cell wall. In this study, spruce wood ( Picea abies Karst.) that had been subjected to high-temperature steaming up to 180 °C was examined, using imaging Fourier Transform Infrared (FT-IR) microscopy and nanoindentation to track changes in the chemical structure and the micromechanical properties of the secondary cell wall. Similar changes in the chemical components, due to the steam treatment, were found in earlywood and latewood. A progressive degradation of the carbonyl groups in the glucuronic acid unit of xylan and a loss of mannose units in the glucomannan backbone, that is, a degradation of glucomannan, together with a loss of the C═O group linked to the aromatic skeleton in lignin, was found. The development of the hygroscopic and micromechanical properties that occurred with an elevation in the steam temperature correlated well with this pattern of degradation in the constituents in the biocomposite matrix in the cell wall (hemicellulose and lignin).

  7. Proteomic Analysis of Responsive Proteins Induced in Japanese Birch Plantlet Treated with Salicylic Acid

    Directory of Open Access Journals (Sweden)

    Hiromu Suzuki

    2014-07-01

    Full Text Available The present study was performed to unravel the mechanisms of systemic acquired resistance (SAR establishment and resistance signaling pathways against the canker-rot fungus (Inonotus obliquus strain IO-U1 infection in Japanese birch plantlet No.8. Modulation of protein-profile induced by salicylic acid (SA-administration was analyzed, and SA-responsive proteins were identified. In total, 5 specifically expressed, 3 significantly increased, and 3 significantly decreased protein spots were identified using liquid chromatography/tandem mass spectrometry (LC/MS/MS and the sequence tag method. These proteins were malate dehydrogenase, succinate dehydrogenase, phosphoglycerate kinase, diaminopimalate decarboxylase, arginase, chorismate mutase, cyclophilin, aminopeptidase, and unknown function proteins. These proteins are considered to be involved in SAR-establishment mechanisms in the Japanese birch plantlet No 8.

  8. Analysis and identification of SCAR molecular markers associated with birch fiber length trait

    Institute of Scientific and Technical Information of China (English)

    WANG Dan; WEI Zhi-gang; YANG Chuan-ping; LIU Guan-jun

    2008-01-01

    The fiber length trait (FLT) of 538 individuals from nature birch population in Maorshan region,Heilongjang,China were measured,of which 100 individuals were selected as representative variety of correlated fragments screening with random amplified polymorphism DNA (RAPD) technique.In total of 20 RAPD primers were tested through multiple regression analysis between amplified strip and the character behaviors,and a correlative segment BFLR-16 was obtained.The correlation coefficient between BFLI-16 and FLT was 0.6144,with the significant level of 1%.BFLI-16 was then cloned,sequenced and transformed into SCAR marker.The percentage of identifying long fiber birches by this SCAR was more than 92.The result indicates that the SCAR markers has high specificity for the long fiber individuals and is highly linked with the gene controlling the character of fiber length,and its existence is significantly correlative with the increase in the fiber length.

  9. Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes

    Directory of Open Access Journals (Sweden)

    Anthi Karnaouri

    2016-03-01

    Full Text Available A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, 13C-solid-state NMR and morphological alterations after pretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while during hydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.

  10. Proteomic Analysis of Responsive Proteins Induced in Japanese Birch Plantlet Treated with Salicylic Acid

    Science.gov (United States)

    Suzuki, Hiromu; Takashima, Yuya; Ishiguri, Futoshi; Yoshizawa, Nobuo; Yokota, Shinso

    2014-01-01

    The present study was performed to unravel the mechanisms of systemic acquired resistance (SAR) establishment and resistance signaling pathways against the canker-rot fungus (Inonotus obliquus strain IO-U1) infection in Japanese birch plantlet No.8. Modulation of protein-profile induced by salicylic acid (SA)-administration was analyzed, and SA-responsive proteins were identified. In total, 5 specifically expressed, 3 significantly increased, and 3 significantly decreased protein spots were identified using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and the sequence tag method. These proteins were malate dehydrogenase, succinate dehydrogenase, phosphoglycerate kinase, diaminopimalate decarboxylase, arginase, chorismate mutase, cyclophilin, aminopeptidase, and unknown function proteins. These proteins are considered to be involved in SAR-establishment mechanisms in the Japanese birch plantlet No 8.

  11. Thermal analysis of wood of the main tree species of Central Siberia

    Directory of Open Access Journals (Sweden)

    S. R. Loskutov

    2015-12-01

    Full Text Available Thermal decomposition of wood from coniferous and deciduous species of Siberia has been studied using thermogravimetry (TG and differential scanning calorimetry (DSC. The tree species were larch Larix sibirica Ledeb., Scots pine Pinus sylvestris L., spruce Picea obovata Ledeb., fir Abies sibirica Ledeb., Siberian pine Pinus sibirica Du Tour., birch Betula pendula Roth., and aspen Populus tremula L. Thermal analysis of wood samples was carried out under oxidative (air and inert (argon atmospheres from 25 to 700 °С at heating rates 10, 20, 40 °С • min–1 (TG/DTG and from 25 to 590 °С at heating rates 10, 40 °С • min–1 (DSC. The stages of thermal decomposition, the temperature intervals, the mass loss, the mass loss rate, the temperature of DTG/DSC peaks, and heating effects were determined for each tree species. The kinetic thermal degradation parameters of wood were obtained by the Broido and Ozawa–Flynn–Wall models. The wood of coniferous and deciduous species of Siberia was characterized on the base of analysis of activation energy values at various stages of thermal decomposition and the relations of activation energy on conversion level of wood substance of different tree species, and also the comparison of mass loss at the same stages of thermal destruction, heating effects, residual mass and other parameters of TG/DTG, DSC. In our opinion, the results of this work present interest for researchers and specialists in the field of forest pyrology, wood science, dendrochemistry.

  12. Effect of CuSO4 Content in the Plating Bath on the Properties of Composites from Electroless Plating of Ni-Cu-P on Birch Veneer

    Directory of Open Access Journals (Sweden)

    Bin Hui

    2014-04-01

    Full Text Available A wood-based composite was prepared via simple electroless Ni-Cu-P plating on birch veneer for EMI shielding. The effects of CuSO4•5H2O concentration on the metal deposition, elemental composition, phase structure, surface morphology, wettability, surface resistivity, and shielding effectiveness of coatings were investigated. The coatings were characterized using X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and scanning electron microscopy (SEM. When the CuSO4•5H2O concentration was increased from 0.6 g/L to 2.2 g/L, the metal deposition was decreased from 79.61 g/m2 to 66.44 g/m2. Elemental composition showed that the copper content in the coating increased significantly, whereas the nickel content was reduced significantly and the phosphorus content was slightly reduced. The crystallinity of coatings increased, and fine-grain structure was observed, with higher copper content. Ni-Cu-P deposition improved the hydrophobic properties when the maximum static contact angle increased from 77.5° to 116.5°. The lowest surface resistivity was 367.5 mΩ/cm2, and the EMI shielding effectiveness of Ni-Cu-P-coated veneers was higher than 60 dB in frequencies ranging from 9 kHz to 1.5 GHz.

  13. Growth and Yield of 15-Year Plantations of Pine, Spruce and Birch in Agricultural Land

    Directory of Open Access Journals (Sweden)

    Daugaviete Mudrite

    2017-07-01

    Full Text Available The growth data and the potential returns from 15-year-old plantations of pine Pinus sylvestris L. (6 trial sites, spruce Picea abies Karst L. (9 trial sites and silver birch Betula pendula Roth (13 trial sites, established in abandoned agricultural lands in a variety of soil types (sod calcareous, anthrosols, podzolic, podzols, gley, podzolic gley, alluvial, using the planting density 2,500 and 3,300 and also 5,000 trees/ha are analysed.

  14. Shelf life extension and sensory evaluation of birch tree sap using chemical preservatives

    Directory of Open Access Journals (Sweden)

    Maciej Bilek

    2016-10-01

    Full Text Available The aim of this study was to assess the stability of the birch tree sap, depending on the addition and concentration of two chemical factors, ie. potassium sorbate and acids: malic, citric or lactic. As in our previous studies we found that the optimal physical parameter to assess the stability of birch sap is turbidity measurement, we used turbidimeter for estimate the effectiveness of shelf life extending. Sensory evaluation was carried out by university sensory panel with 8 skilled people (students and teachers with pre-selection and basic training of sensory methodology. On the other hand artificial perception measurements were realized by electronic nose. Birch tree sap stability without addition of preservatives, both room temperature and refrigerated, is less than three days. The effectiveness of preservation of birch tree sap depends on the concentration of acids. Independently of storage temperature, samples that received stability during the whole one-month storage period, were those with potassium sorbate and three acids in the highest concentrations, ie. malic acid at 0.3%, citric acid at 0.5% and lactic acid at 0.5%. Unfortunately, concentrations of acids, which allow extension of shelf life at least for one month in a room temperature, are characterized by the worst sensory evaluation rating. Thus, they should be corrected by the use of additives for improving the flavor, such as fruit syrups or herbal extracts. On the other hand, additionally storage in a refrigerated conditions allows one-month-stability for the sample with the highest sensory evaluation rating, ie. with the addition of lactic acid at 0.1% and potassium sorbate, which taste not need to be corrected.

  15. Chemical composition and speciation of particulate organic matter from modern residential small-scale wood combustion appliances.

    Science.gov (United States)

    Czech, Hendryk; Miersch, Toni; Orasche, Jürgen; Abbaszade, Gülcin; Sippula, Olli; Tissari, Jarkko; Michalke, Bernhard; Schnelle-Kreis, Jürgen; Streibel, Thorsten; Jokiniemi, Jorma; Zimmermann, Ralf

    2017-08-31

    Combustion technologies of small-scale wood combustion appliances are continuously developed decrease emissions of various pollutants and increase energy conversion. One strategy to reduce emissions is the implementation of air staging technology in secondary air supply, which became an established technique for modern wood combustion appliances. On that account, emissions from a modern masonry heater fuelled with three types of common logwood (beech, birch and spruce) and a modern pellet boiler fuelled with commercial softwood pellets were investigated, which refer to representative combustion appliances in northern Europe In particular, emphasis was put on the organic constituents of PM2.5, including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and phenolic species, by targeted and non-targeted mass spectrometric analysis techniques. Compared to conventional wood stoves and pellet boilers, organic emissions from the modern appliances were reduced by at least one order of magnitude, but to a different extent for single species. Hence, characteristic ratios of emission constituents and emission profiles for wood combustion identification and speciation do not hold for this type of advanced combustion technology. Additionally, an overall substantial reduction of typical wood combustion markers, such as phenolic species and anhydrous sugars, were observed. Finally, it was found that slow ignition of log woods changes the distribution of characteristic resin acids and phytosterols as well as their thermal alteration products, which are used as markers for specific wood types. Our results should be considered for wood combustion identification in positive matrix factorisation or chemical mass balance in northern Europe. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Mountain birch – potentially large source of sesquiterpenes into high latitude atmosphere

    Directory of Open Access Journals (Sweden)

    S. Haapanala

    2009-06-01

    Full Text Available Emissions of volatile organic compounds (VOCs from mountain birches were measured in Abisko, northern Sweden. Mountain birches make up majority of the tree biomass in Scandinavian high latitudes, area subject to significant climate warming. The measurements were carried out in two growing seasons. The emissions of a branch from four individual trees were measured in June–August 2006 and one of them again in July 2007. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. The studied mountain birches were found to emit substantial amounts of linalool, monoterpenes and sesquiterpenes. The monoterpene emission was dominated by sabinene. The magnitude and composition of sesquiterpene emission changed dramatically between the years. For example, the average α-farnesene emission in 2006 was almost 2000 ng gdw−1 h−1 while in 2007 the emission of α-farnesene was negligible. Also the emissions of other sesquiterpenes decreased in 2007 to a fraction of that in 2006. One possible explanation for the change in emissions is the herbivory damage that occurred in the area in 2004. Herbivory is known to enhance the emissions of sesquiterpenes, especially those of α-farnesene, and the effect may last several years.

  17. Mountain birch – potentially large source of sesquiterpenes into high latitude atmosphere

    Directory of Open Access Journals (Sweden)

    A. Arneth

    2009-11-01

    Full Text Available Emissions of volatile organic compounds (VOCs from mountain birches were measured in Abisko, northern Sweden. Mountain birches make up the majority of the tree biomass in Scandinavian high latitudes, a region subject to significant climate warming. The measurements were carried out in two growing seasons. The emissions of four branches, each from a different individual tree, were measured in June–August 2006 and one of them again in July 2007. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. The studied mountain birches were found to emit substantial amounts of linalool, monoterpenes and sesquiterpenes. The monoterpene emission was dominated by sabinene. The magnitude and composition of the sesquiterpene emission changed dramatically between the years. For example, the average α-farnesene emission potential in 2006 was almost 2600 ng gdw−1 h−1 (3.5 pmol gdw−1 s−1 while in 2007 α-farnesene was not detected at all. Also the emissions of other sesquiterpenes decreased in 2007 to a fraction of that in 2006. One possible explanation for the change in emissions is the herbivory damage that occurred in the area in 2004. Herbivory is known to enhance the emissions of sesquiterpenes, especially those of α-farnesene, and the effect may last for several years.

  18. Growth of Scots Pine and Silver Birch Seedlings on Different Nursery Container Media

    Directory of Open Access Journals (Sweden)

    Fahrettin TILKI

    2014-12-01

    Full Text Available Peat has been the most common growing medium in tree nurseries, either alone or as a component of growing media mixes. However, as a result of increasing costs and decreasing amount of peat, seedling-growers are seeking more local growing medium components. In this study, container seedlings of Scots pine (Pinus sylvestris L. and silver birch (Betula pendula Roth were grown in pure peat and peat mixtures containing perlite and zeolite.  Physical parameters (height, shoot diameter, root dry weight, shoot dry weight, total dry weight were measured along with several morphological parameters (sturdiness quotient, height/diameter, shoot/root ratio. The zeolite additive in peat changed some media properties, and significant relation was established between some morphological attributes of seedlings and some medium properties in both species. On average, the seedlings grew best in pure peat, but zeolite additions to peat did not affect some morphological parameters negatively. The results suggest that zeolite has potential to be used as a component of peat based growing medium mixtures, and addition of zeolite to peat container medium in proportions of 10% by volume in Scots pine and up to 20% in silver birch was shown to be a feasible material for growing Scots pine and silver birch seedlings.

  19. Icelandic Birch Polyploids—The Case of a Perfect Fit in Genome Size

    Directory of Open Access Journals (Sweden)

    K. Anamthawat-Jónsson

    2010-01-01

    Full Text Available Two birch species coexist in Iceland, dwarf birch Betula nana and tree birch B. pubescens. Both species are variable morphologically, which has been shown to be due to introgressive hybridization via interspecific hybrids. The aim of this study was to examine if the introgression could be related to genome size. We characterized 42 plants from Bifröst woodland morphologically and cytogenetically. The population consisted of diploid B. nana (38%, tetraploid B. pubescens (55%, and triploid hybrids (7%. Genome size was measured from 12 plants, using Feulgen DNA image densitometry (FDM on spring leaf buds and flow cytometry (FCM with dormant winter twigs. The use of winter twigs for FCM is novel. The average 1C-values for diploid, triploid, and tetraploid plants were 448, 666, and 882 Mbp, respectively. Monoploid genome sizes were found to be statistically constant among ploidy levels. This stability is in contrast to the different taxonomic positions of the di- and tetraploids and also contrasts with the frequent occurrence of genome downsizing in polyploids.

  20. Identification of SSR loci in Betula luminifera using birch EST data

    Institute of Scientific and Technical Information of China (English)

    LU Yong-quan; LI Hai-ying; JIA Qing; HUANG Hua-hong; TONG Zai-kang

    2011-01-01

    Expressed sequence tags (ESTs) are generated from single-pass sequencing of randomly picked cDNA clones and can be used for development of simple sequence repeat (SSR) markers or microsatellites.However,EST databases have been developed for only a small number of species.This paper provides a case study of the utility of freely available birch EST reources for the development of markers necessary for the genetic analysis of Betula luminifera.Based on birch EST data,primers for 80 EST-SSR candidate loci were developed and tested in birch.Of these,59 EST-SSR loci yielded single,stable and clear PCR products.We then tested the utility of those 59 markers in B.luminifera.The results showed 28 (47.6%) yielded stable and clear PCR products for at least one B.luminifera genotype.In addition,this study describes a rapid and inexpensive alternative for the development of SSRs in species with scarce available sequence data.

  1. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    Eric C. Xu; Yajun Zhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes.The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  2. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    EricC.Xu; YajunZhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes. The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  3. Nanoscale in Wood, Nanowood and Wood-Inorganic Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Zhao Guangjie; Lu Wenhua

    2003-01-01

    In order to introduce nano science and technology (NST) into the research field of wood science and technology, andpromote the research of wood science and wood-inorganic composites to nanoscale, some new concepts, such as the nano space inwood, nano structure units of wood and nanowood are put forward in this paper based on the layer structure of wood cell wall and thepile-up model of its main components. Furthermore, the process of preparing nanowood is discussed, and wood-inorganic nanocom-posites may be operated in three ways with wood (matrix) and inorganic filler phase in 0-2, 0-3 or 2-3 dimensions respectively. Thefollowing results are obtained: (1) The nanoscale voids in wood indicate that wood has inherent space to accommodate nanosizedmaterials, such as nanoparticles, nanotubes and nanosticks; (2) According to the size from top down, the nano structure units in woodcan be classified as: nanolayers, nano CMF (cellulose microfibril) and matrix, nano crystallite units and cellulose chain clusters, andthese can theoretically form nanowood; (3) The preparation of wood-inorganic nanocomposites can be operated on 0-2, 0-3 or 2-3dimensions.

  4. Xylan degradation by the human gut Bacteroides xylanisolvens XB1A(T) involves two distinct gene clusters that are linked at the transcriptional level.

    Science.gov (United States)

    Despres, Jordane; Forano, Evelyne; Lepercq, Pascale; Comtet-Marre, Sophie; Jubelin, Gregory; Chambon, Christophe; Yeoman, Carl J; Berg Miller, Margaret E; Fields, Christopher J; Martens, Eric; Terrapon, Nicolas; Henrissat, Bernard; White, Bryan A; Mosoni, Pascale

    2016-05-04

    Plant cell wall (PCW) polysaccharides and especially xylans constitute an important part of human diet. Xylans are not degraded by human digestive enzymes in the upper digestive tract and therefore reach the colon where they are subjected to extensive degradation by some members of the symbiotic microbiota. Xylanolytic bacteria are the first degraders of these complex polysaccharides and they release breakdown products that can have beneficial effects on human health. In order to understand better how these bacteria metabolize xylans in the colon, this study was undertaken to investigate xylan breakdown by the prominent human gut symbiont Bacteroides xylanisolvens XB1A(T). Transcriptomic analyses of B. xylanisolvens XB1A(T) grown on insoluble oat-spelt xylan (OSX) at mid- and late-log phases highlighted genes in a polysaccharide utilization locus (PUL), hereafter called PUL 43, and genes in a fragmentary remnant of another PUL, hereafter referred to as rPUL 70, which were highly overexpressed on OSX relative to glucose. Proteomic analyses supported the up-regulation of several genes belonging to PUL 43 and showed the important over-production of a CBM4-containing GH10 endo-xylanase. We also show that PUL 43 is organized in two operons and that the knockout of the PUL 43 sensor/regulator HTCS gene blocked the growth of the mutant on insoluble OSX and soluble wheat arabinoxylan (WAX). The mutation not only repressed gene expression in the PUL 43 operons but also repressed gene expression in rPUL 70. This study shows that xylan degradation by B. xylanisolvens XB1A(T) is orchestrated by one PUL and one PUL remnant that are linked at the transcriptional level. Coupled to studies on other xylanolytic Bacteroides species, our data emphasize the importance of one peculiar CBM4-containing GH10 endo-xylanase in xylan breakdown and that this modular enzyme may be used as a functional marker of xylan degradation in the human gut. Our results also suggest that B. xylanisolvens

  5. 玉米芯中木聚糖提取方法的研究%Experimental Study on Production of Xylan from Corncob

    Institute of Scientific and Technical Information of China (English)

    赵灵希; 郭仁杰; 熊海容

    2012-01-01

    In this study xylan was obtained from corncob by base-hydrolysis,30% hydrogenperoxide and 10% trichloroacetic acid and the extraction rate was 24.4%.Comparing with the Michaelis constant of the same xylanase produced by Thermomyces lanuginosus DSM10635,which separately used three different kinds of xylan and xylan extracted by us as substrates,Km 7.5303 of xylan extracted by us is similar with Km 5.6044 of oak xylan.Then comparing with the optimatemparature of DSM10635 xylanase which used brich xylan and the extacted-xylan as substrates,the optimal temperature was about 65-70℃.This induced that it can substitute for brich xylan.The method of extraction was simple and the high yield have the significance to the mass-produce of xylan in industry.%采用碱解玉米芯粉末后,玉米芯碱解液用30%(w:v)过氧化氢溶液脱色并且用10%(w:v)三氯乙酸溶液脱蛋白来提取木聚糖,收得率分别为24.4%。并用真菌DSM10635菌株产的木聚糖酶对以三种不同来源的木聚糖以及自提玉米芯木聚糖为底物测得的米氏常数进行比较,还检测比较了DSM 10635木聚糖酶以桦树和自提木聚糖作为底物的最佳酶促反应温度。结果表明,从玉米芯自提木聚糖的Km值7.5303与燕麦木聚糖的Km值5.6044相近,桦树和自提的木聚糖的最佳酶促反应温度也都在65-70℃左右,具有一定的取代性。方法简单,收得率较高的木聚糖提取方法对工业上大量生产具有重要的意义。

  6. Preparation of Polyvinyl Alcohol/Xylan Blending Films with 1,2,3,4-Butane Tetracarboxylic Acid as a New Plasticizer

    Directory of Open Access Journals (Sweden)

    Cun-dian Gao

    2014-01-01

    Full Text Available Miscible, biodegradable polyvinyl alcohol (PVA/xylan blending films were firstly prepared in the range of the PVA/xylan weight ratio from 1 : 2 to 3 : 1 by casting method using 1,2,3,4-butane tetracarboxylic acid (BTCA as a new plasticizer. The properties of blending films as functions of PVA/xylan weight ratio and BTCA amount were discussed. XRD and FT-IR were applied to characterize the blending films. Experimental results indicated that tensile strength (TS and elongation at break (EAB of blending films decreased along with the decrease of the PVA/xylan weight ratio. Both of TS and EAB firstly increased and then decreased as the amount of BTCA was increased. More importantly, blending films were biodegraded almost by 41% with an addition of 10% BTCA in blending films within 30 days in soil. For all hydroxyl functionalized polymers (xylan and PVA, their molecular interactions and miscibility with BTCA endowed blending films with the biocompatibility and biodegradability. Therefore, these blending films are environmentally friendly materials which could be applied as biodegradable plastics for food packaging and agricultural applications.

  7. Improvement of the quality of wood derived biofuel-oils; Puuperaeisten biopolttooeljyjen laadun parantaminen. Raakasuovan terminen nestefaasikaesittely hiilivety-polttoaineiksi

    Energy Technology Data Exchange (ETDEWEB)

    Oasmaa, A.; McKeough, P.; Kuoppala, E.; Kylloenen, H.; Levander, J.; Tapola, E.; Haekkinen, R.

    1995-12-31

    Liquid-phase thermochemical processing of tall oil soap has been experimentally investigated. The organic matter of tall oil soap, which is a by-product of kraft pulping, originates mainly from wood extractives. Conventional processing of tall oil soap involves acidulation to yield crude tall oil and subsequent distillation of the oil at centralized refineries. Because tall oil originating from birch wood is far less valuable than that from pine, there is an economic incentive in the Nordic countries to develop alternative conversion processes for the tall oil soap produced at pulp mills where birch is widely used as feedstock. Both catalytic hydrotreatment and liquid-phase thermal treatment of a mixed pine/birch soap have been investigated in the laboratory. Liquid and gaseous hydrocarbons were the principal products formed in both types of treatment. Although the liquid product formed under hydrotreatment conditions contained a higher proportion of aliphatic compounds, it was clear that the thermal treatment process would be, economically, the more favorable option. In the thermal process, a predominantly hydrocarbon oil product was obtained at 450 deg C using a residence time of at least 60 min. About 50 % of the energy content of the tall oil soap was recovered as oil product, about 30 % as gases, and about 20 % as organic material contained in an aqueous slurry phase. When the oil product was carefully separated from the aqueous slurry phase, only trace amounts of impurities, such as water, sodium and organic acid salts were present in the product. A techno-economic evaluation of the process concept has been performed. The economics of the thermal treatment process appear to be favorable in comparison with those of the conventional acidulation process

  8. Lignin-Retaining Transparent Wood.

    Science.gov (United States)

    Li, Yuanyuan; Fu, Qiliang; Rojas, Ramiro; Yan, Min; Lawoko, Martin; Berglund, Lars

    2017-09-11

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK(-1) , and work-tofracture of 1.2 MJ m(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  9. Compressive Fatigue in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1999-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Small clear specimens of spruce are taken to failure in square wave formed fatigue loading at a stress excitation level corresponding to 80% of the short term strength. Four...... frequencies ranging from 0.01 Hz to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation...... is observed between stiffness reduction and accumulated creep. A failure model based on the total work during the fatigue life is rejected, and a modified work model based on elastic, viscous and non-recovered viscoelastic work is experimentally supported, and an explanation at a microstructural level...

  10. Enzymatic hydrolysis of xylan extracted with alkali%碱法提取木聚糖的酶法水解

    Institute of Scientific and Technical Information of China (English)

    杨瑞金; 许时婴; 王璋

    2001-01-01

    在进行碱法提取木聚糖的酶法水解时,采用3%~4%的底物浓度和20U/g底物的加酶量比较合适。在优化的条件下,产品的低聚木糖含量达到79.1%(对总糖),得率达到66.8%。以去除阿拉伯糖侧链为目的,稀酸预水解对随后的碱法提取木聚糖的酶水解作用不大。这表明在木聚糖的酶水解过程中,阿拉伯糖侧链与整个木聚糖的水解同步进行。%The rational substrate concentration was 3%~4% and the properamount of xylanase was 20U/g substrate for the enzymatic hydro ly sis of xylan extracted with alkali.In the optimal condition,the product had a pu rity of 79.1% on carbohydrate basis and the yield of xylooligosacchrides could be up to 66.8%.Acidic pre-hydrolysis of the xylan extracted with alkali for rem oving the arabinose sidechain had less effect on the following enzymatic hydroly sis.It suggested that the hydrolysis of the arabinose side-chain was simultaneo us with that of the xylan.

  11. Characterization of PR-10 genes from eight Betula species and detection of Bet v 1 isoforms in birch pollen.

    Science.gov (United States)

    Schenk, Martijn F; Cordewener, Jan H G; America, Antoine H P; Van't Westende, Wendy P C; Smulders, Marinus J M; Gilissen, Luud J W J

    2009-03-03

    Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch (Betula pendula) have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the genome was established by amplification and sequencing of alleles from eight birch species that represent the four subgenera within the genus Betula. Q-TOF LC-MSE was applied to identify which PR-10/Bet v 1 genes are actually expressed in pollen and to determine the relative abundances of individual isoforms in the pollen proteome. All examined birch species contained several PR-10 genes. In total, 134 unique sequences were recovered. Sequences were attributed to different genes or pseudogenes that were, in turn, ordered into seven subfamilies. Five subfamilies were common to all birch species. Genes of two subfamilies were expressed in pollen, while each birch species expressed a mixture of isoforms with at least four different isoforms. Isoforms that were similar to isoforms with a high IgE-reactivity (Bet v 1a = PR-10.01A01) were abundant in all species except B. lenta, while the hypoallergenic isoform Bet v 1d (= PR-10.01B01) was only found in B. pendula and its closest relatives. Q-TOF LC-MSE allows efficient screening of Bet v 1 isoforms by determining the presence and relative abundance of these isoforms in pollen. B. pendula contains a Bet v 1-mixture in which isoforms with a high and low IgE-reactivity are both abundant. With the possible exception of B. lenta, isoforms identical or very similar to those with a high IgE-reactivity were found in the pollen proteome of all examined birch species. Consequently, these species are also predicted to be allergenic with regard to Bet v 1 related allergies.

  12. Controlling mold on wood Pallets

    Science.gov (United States)

    Carol A. Clausen

    2012-01-01

    THE WOOD PALLET AND CONTAINER INDUSTRY CONSUMES 4.5 billion board feet (BBF) of hardwoods and 1.8 BBF of softwoods for the annual production of 400-500 million solid wood pallets. While alternative materials such as plastic, corrugated paperboard and metal have entered the market, solid wood remains the material of choice for a majority of pallets on the market (more...

  13. Ground Wood Fiber Length Distributions

    OpenAIRE

    Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.

    2014-01-01

    This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...

  14. Application of wood chips for soil mulching in the cultivation of ornamental grasses

    Directory of Open Access Journals (Sweden)

    Henschke Monika

    2016-12-01

    Full Text Available A mulch is a layer of material applied to the surface of the soil. Mulching plays an important role in the maintenance of green spaces. Organic materials are still sought for the preparation of mulches. Recently interest in wood chips has grown. The aim of the study was to determine the effect of mulching with pine and birch chips on the contents of phenolic compounds in the soil, as well as on the growth and flowering of ornamental grasses – Bouteloua gracilis (Kunth. Lag. ex Griffiths, Panicum virgatum L. and Pennisetum alopecuroides L. The content of phenolic compounds in the soil steadily increased from spring to autumn. Mulching led to a substantial increase in the level of phenolic compounds. In the first year of cultivation more phenolic compounds were released by chips of pine than birch, while in the second year this difference did not occur. Mulching had a negative impact on the growth and flowering of ornamental grasses, especially in the first year of cultivation. Ornamental grass sensitivity to the substances released from mulches decreased with the age of the plants and was dependent on the species – Bouteloua gracilis was found to be particularly sensitive.

  15. Extração e caracterização de xilanas de sabugos de milho Extraction and characterization of xylans from corncobs

    Directory of Open Access Journals (Sweden)

    Simone S. Silva

    1998-06-01

    Full Text Available Neste trabalho, duas frações de xilana, denominadas xilana A e xilana B, foram isoladas a partir de sabugos de milho através de três processos diferentes, combinando métodos de extração aquosa, remoção de lipídeos, deslignificação e extração alcalina. Os produtos obtidos durante os processos foram analisados por termogravimetria. A etapa de deslignificação foi responsável por uma acentuada degradação dos polímeros, evidenciada por queda de rendimento e resistência térmica. Os espectros obtidos no infravermelho evidenciaram a ausência de ácidos urônicos na cadeia polimérica. As viscosidades intrínsecas obtidas para a xilana A (56 mL/g e xilana B (75 mL/g associadas aos resultados do infravermelho sugerem um número maior de grupos substituintes, constituídos basicamente por resíduos de L-arabinose, para a xilana B.In this work, two fractions of xylan, named xylan A and xylan B, were isolated from corncobs through three different processes using aqueous extraction, lipid removal, delignification, and alkaline extraction. The products obtained during the processes were analysed by thermogravimetry. The delignification step was responsible for the occurrence of an accentuated polymer degradation, evidenced by yield and thermal resistance decrease. Infrared spectra indicated the absence of uronic acids in the polymeric chains. Intrinsic viscosities obtained for xylan A (56 mL/g and xylan B (75 mL/g, associated to the results from i.r. analysis, suggested a higher number of substituents, basically constituted of L-arabinose residues, in the case of xylan B.

  16. Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions

    Science.gov (United States)

    Avagyan, Rozanna; Nyström, Robin; Lindgren, Robert; Boman, Christoffer; Westerholm, Roger

    2016-09-01

    Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography - photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 μg/MJfuel and 32.5 μg/MJfuel for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are

  17. INFLUENCE OF HEAT TRANSFERRING MEDIA ON DURABILITY OF THERMALLY MODIFIED WOOD

    Directory of Open Access Journals (Sweden)

    Olov Karlsson

    2011-02-01

    Full Text Available Studies on the durability and dimensional stability of a series of hardwoods and softwoods after thermal modification in vegetable oils and in steam atmospheres have been performed. Mass loss after exposure to Coniophora puteana (BAM Ebw.15 for 16 weeks was very low for European birch, European aspen, Norway spruce, and Scots pine thermally modified in a linseed oil product with preservative (for 1 hour at 200 oC. Fairly low mass losses were obtained for wood thermally modified in linseed-, tung- and rapeseed oil, and losses were related to the wood species. Low mass loss during rot test was also found for Norway spruce and Scots pine modified in saturated steam at 180 oC. Water absorption of pine and aspen was reduced by the thermal treatments and the extent of reduction was dependent on wood species and thermal modification method. Thermally modified aspen was stable during cycling climate tests, whereas pine showed considerable cracking when modified under superheated steam conditions (Thermo D. At lower modification temperature (180 oC an increase in mass after modification in rapeseed oil of spruce, aspen and sapwood as well as heartwood of pine was observed, whereas at high temperature (240 oC a mass loss could be found. Oil absorption in room tempered oil after thermal modification in oil was high for the more permeable aspen and pine (sapwood.

  18. Biobutanol production by Clostridium acetobutylicum using xylose recovered from birch Kraft black liquor.

    Science.gov (United States)

    Kudahettige-Nilsson, Rasika L; Helmerius, Jonas; Nilsson, Robert T; Sjöblom, Magnus; Hodge, David B; Rova, Ulrika

    2015-01-01

    Acetone-butanol-ethanol (ABE) fermentation was studied using acid-hydrolyzed xylan recovered from hardwood Kraft black liquor by CO2 acidification as the only carbon source. Detoxification of hydrolyzate using activated carbon was conducted to evaluate the impact of inhibitor removal and fermentation. Xylose hydrolysis yields as high as 18.4% were demonstrated at the highest severity hydrolysis condition. Detoxification using active carbon was effective for removal of both phenolics (76-81%) and HMF (38-52%). Batch fermentation of the hydrolyzate and semi-defined P2 media resulted in a total solvent yield of 0.12-0.13g/g and 0.34g/g, corresponding to a butanol concentration of 1.8-2.1g/L and 7.3g/L respectively. This work is the first study of a process for the production of a biologically-derived biofuel from hemicelluloses solubilized during Kraft pulping and demonstrates the feasibility of utilizing xylan recovered directly from industrial Kraft pulping liquors as a feedstock for biological production of biofuels such as butanol. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Short-rotation plantations. Wood from the acre - that's the way; Kurzumtriebsplantagen. Holz vom Acker - So geht's

    Energy Technology Data Exchange (ETDEWEB)

    Setzer, Frank [Deutsche Landwirtschaftsgesellschaft, Frankfurt am Main (Germany). Fachgebiet Forstwirtschaft und Bioenergie; Landgraf, Dirk

    2012-07-01

    Poplar or willow instead of rapeseed and wheat? It is not quite obviously: There is no question that one may achieve still more profits by means of cultivation of quality wheat than the cultivation of fast growing wood. However, under certain circumstances birch trees, robinia et cetera may be a very lucrative alternative to grassland or low yield rye cultivation. Especially with currently rising timber prices. The book under consideration is a practical decision support for whom a short-rotation plantations is worthwhile as well as how to create and maintain a short-rotation plantation.

  20. Synthesis and Characterization of Bagasse Xylan Acetates%蔗渣木聚糖醋酸酯的合成与表征

    Institute of Scientific and Technical Information of China (English)

    李和平; 李东旭; 鲁勇

    2011-01-01

    以蔗渣木聚糖为原料,醋酸酐为酯化剂,对甲基苯磺酸为催化剂,在冰醋酸体系中合成了蔗渣木聚糖醋酸酯.考察了诸因素对产品取代度的影响.在m(木聚糖):m(醋酸酐)=4:5,m(木聚糖):m(催化剂)=4:0.2,m(木聚糖):m(冰醋酸)=4:10.49,酯化温度为70℃.酯化时间为4 h的条件下,合成r取代度为0.20的蔗渣木聚糖醋酸酯.采用FTIR、XRD和SEM对蔗渣木聚糖醋酸酯结构进行了表征.分别测定了蔗渣木聚糖醋酸酯的糊化性能和热黏度,表明蔗渣木聚糖醋酸酯比蔗渣木聚糖糊化温度低,热黏稳定性显著改善.%Bagasse xylan acetates was synthesized by using bagasse xylan as raw materials, acetic anhydride as esterifying agent,p-toluenesulfonic acid(PTSA) as activation catalyst and acetic acid as the solvent. The influence of the various reaction conditions on the degree of substitution of bagasse xylan acetates was investigated. The degree of substitution of the product was 0. 20 under the conditions of m(xylan)∶m( acetic anhydride) =4∶5 ,m(xylan)∶m(PTSA) =4∶0.2, m(xylan)∶m( acetic acid) =4∶10.49,reaction temperature 70 ℃, reaction time 4 h. The structure was characterizated by FTIR,XRD and SEM, during the process of which the gelatinization properties and the thermal viscosity of bagasse xylan acetates were separately determined, which indicates that the gelatinization temperature of bagasse xylan acetates was .lower and the stability of thermal viscosity was significantly improved.

  1. Corrosion of Fasteners in Wood Treated with Newer Wood Preservatives

    Science.gov (United States)

    Samuel L. Zelinka

    2013-01-01

    This document compiles recent research findings related to corrosion of metals in preservative treated wood into a single report on corrosion of metals in wood. The research was conducted as part of the Research, Technology and Education portion of the National Historic Covered Bridge Preservation (NHCBP) Program administered by the Federal Highway Administration. The...

  2. Bacteroides intestinalis DSM 17393, a member of the human colonic microbiome, upregulates multiple endoxylanases during growth on xylan

    Science.gov (United States)

    Wang, Kui; Pereira, Gabriel V.; Cavalcante, Janaina J. V.; Zhang, Meiling; Mackie, Roderick; Cann, Isaac

    2016-01-01

    Many human diets contain arabinoxylan, and the ease of genome sequencing coupled with reduced cost have led to unraveling the arsenal of genes utilized by the colonic Bacteroidetes to depolymerize this polysaccharide. The colonic Bacteroidetes with potential to ferment arabinoxylans include Bacteroides intestinalis. In this study, we analyzed the hydrolytic activities of members of a xylan degradation cluster encoded on the genome of Bacteroides intestinalis DSM 17393. Here, it is demonstrated that a cocktail of the xylanolytic enzymes completely hydrolyze arabinoxylans found in human diets. We show that this bacterium and relatives have evolved and secrete a unique bifunctional endoxylanase/arabinofuranosidase in the same polypeptide. The bifunctional enzyme and other secreted enzymes attack the polysaccharides extracellularly to remove the side-chains, exposing the xylan backbone for cleavage to xylo-oligosaccharides and xylose. These end products are transported into the cell where a β-xylosidase cleaves the oligosaccharides to fermentable sugars. While our experiments focused on B. intestinalis, it is likely that the extracellular enzymes also release nutrients to members of the colonic microbial community that practice cross-feeding. The presence of the genes characterized in this study in other colonic Bacteroidetes suggests a conserved strategy for energy acquisition from arabinoxylan, a component of human diets. PMID:27681607

  3. Wood pole overhead lines

    CERN Document Server

    Wareing, Brian

    2005-01-01

    This new book concentrates on the mechanical aspects of distribution wood pole lines, including live line working, environmental influences, climate change and international standards. Other topics include statutory requirements, safety, profiling, traditional and probabilistic design, weather loads, bare and covered conductors, different types of overhead systems, conductor choice, construction and maintenance. A section has also been devoted to the topic of lightning, which is one of the major sources of faults on overhead lines. The book focuses on the effects of this problem and the strate

  4. Wood-related occupations, wood dust exposure, and sinonasal cancer.

    Science.gov (United States)

    Hayes, R B; Gerin, M; Raatgever, J W; de Bruyn, A

    1986-10-01

    A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

  5. High environmental ozone levels lead to enhanced allergenicity of birch pollen.

    Directory of Open Access Journals (Sweden)

    Isabelle Beck

    Full Text Available BACKGROUND: Evidence is compelling for a positive correlation between climate change, urbanisation and prevalence of allergic sensitisation and diseases. The reason for this association is not clear to date. Some data point to a pro-allergenic effect of anthropogenic factors on susceptible individuals. OBJECTIVES: To evaluate the impact of urbanisation and climate change on pollen allergenicity. METHODS: Catkins were sampled from birch trees from different sites across the greater area of Munich, pollen were isolated and an urbanisation index, NO2 and ozone exposure were determined. To estimate pollen allergenicity, allergen content and pollen-associated lipid mediators were measured in aqueous pollen extracts. Immune stimulatory and modulatory capacity of pollen was assessed by neutrophil migration assays and the potential of pollen to inhibit dendritic cell interleukin-12 response. In vivo allergenicity was assessed by skin prick tests. RESULTS: The study revealed ozone as a prominent environmental factor influencing the allergenicity of birch pollen. Enhanced allergenicity, as assessed in skin prick tests, was mirrored by enhanced allergen content. Beyond that, ozone induced changes in lipid composition and chemotactic and immune modulatory potential of the pollen. Higher ozone-exposed pollen was characterised by less immune modulatory but higher immune stimulatory potential. CONCLUSION: It is likely that future climate change along with increasing urbanisation will lead to rising ozone concentrations in the next decades. Our study indicates that ozone is a crucial factor leading to clinically relevant enhanced allergenicity of birch pollen. Thus, with increasing temperatures and increasing ozone levels, also symptoms of pollen allergic patients may increase further.

  6. Adaptive Responses of Birch-Leaved Pear (Pyrus betulaefolia Seedlings to Salinity Stress

    Directory of Open Access Journals (Sweden)

    Qiang Sheng WU

    2009-06-01

    Full Text Available One-year-old birch-leaved pear (Pyrus betulaefolia Bunge seedlings were subjected to 0, 50, 100, 150, and 200 mmol/L NaCl solutions for 27 days in order to study the effects of salinity stress on photosynthesis, ion accumulation and enzymatic and non-enzymatic scavenging of reactive oxygen species in the seedlings. The research was performed in a greenhouse using potted trees. Salinity stress reduced photosynthetic rates, stomatal conductance and water use efficiency of leaves of the pear seedlings, but increased transpiration rates and leaf temperature. Hydrogen peroxide and superoxide anion radical contents increased with increasing NaCl concentrations, a phenomena also observed for malondialdehyde, suggesting that leaves of the pear seedlings suffered from oxidative injury. Superoxide dismutase (SOD and catalase (CAT activities quickly responded by increasing when the pear seedlings were subjected to salinity stress. Total protein content in leaves of the seedlings was restrained by salinity stress, whereas ascorbate content increased. Salinity stress reduced glutathione content once the birch-leaved pear seedlings were exposed to a low level (50 or 100 mmol/L of NaCl, whereas a high level (150 or 200 mmol/L NaCl of salinity stress stimulated the accumulation of glutathione. Salinity stress increased the accumulation of Na+, Cl-, K+ and Mg2+ in the seedlings, but reduced Ca2+ levels and the ratio of other ions to Na+ except K+/Na+ under 50 mmol/L NaCl conditions. This suggests that leaves of birch-leaved pear seedlings possess the capacity for salt exclusion only under 50 mmol/L NaCl conditions, and Ca2+ does not play a fundamental role as a secondary messenger under salinity stress conditions.

  7. CO2 response to rewetting of hydrophobic soils - Can soil water repellency inhibit the 'Birch effect'?

    Science.gov (United States)

    Sanchez-Garcia, Carmen; Urbanek, Emilia; Doerr, Stefan

    2017-04-01

    Rewetting of dry soils is known to cause a short-term CO2 pulse commonly known as the 'Birch effect'. The displacement of CO2 with water during the process of wetting has been recognised as one of the sources of this pulse. The 'Birch effect' has been extensively observed in many soils, but some studies report a lack of such phenomenon, suggesting soil water repellency (SWR) as a potential cause. Water infiltration in water repellent soils can be severely restricted, causing overland flow or increased preferential flow, resulting in only a small proportion of soil pores being filled with water and therefore small gas-water replacement during wetting. Despite the suggestions of a different response of CO2 fluxes to wetting under hydrophobic conditions, this theory has never been tested. The aim of this study is to test the hypothesis that CO2 pulse does not occur during rewetting of water repellent soils. Dry homogeneous soils at water-repellent and wettable status have been rewetted with different amounts of water. CO2 flux as a response to wetting has been continuously measured with the CO2 flux analyser. Delays in infiltration and non-uniform heterogeneous water flow were observed in water repellent soils, causing an altered response in the CO2 pulse in comparison to typically observed 'Birch effect' in wettable systems. The main conclusion from the study is that water repellency not only affects water relations in soil, but has also an impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  8. Isolation and identification of plant phenolic compounds in birch leaves: Air pollution stress and leaf phenolics

    Science.gov (United States)

    Loponen, Jyrki Mikael

    Chromatographic (analytical and preparative HPLC), chemical (hydrolysis) and spectroscopic (UV, 1H NMR, 13C NMR and MS) techniques proved to be suitable tools for the structure identification of plant phenolic compounds. More than 30 individual phenolic compounds were detected and quantified. Detailed information of the structures of individual compounds was determined after isolation from birch leaves. Ten flavonoid glycosides were identified. Two of them, myricetin-3-O-α-L-(acetyl)-rhamnopyranoside and quercetin-3-O-α-L-(4/prime'-O-acetyl)- rhamnopyranoside, have been rarely found in birch leaves. Further, some characterized major phenolics with non- flavonoid structures in our study were 1-O-galloyl- β-D-(2-O-acetyl)-glucopyranose, gallic, chlorogenic, neochlorogenic, cis- and trans-forms of 3- and 5-p-coumaroylquinic acids. The presence of gallotannin group was evidenced by strong positive correlations between concentrations of these gallotannins (preliminary identified by HPLC and UV spectra) and the protein precipitation capacity of extracts. Content of gallotannins decreased with leaf growth and maturation. It is known that concentrations of phenolic compounds regularly increase in slowly growing stressed plants and therefore, it is natural that they are also sensitive to different forms of air pollution. Total content and the contents of some individual phenolics correlated negatively with the distance from the pollution source in our study area. In addition to comparing absolute concentrations of compounds in question, the within-tree correlations or within-tree variations of the relevant compounds between polluted and control areas were an alternative approach. Differences in pairwise correlations between the investigated leaf phenolic compounds indicated the competition between some gallotannins and p-coumaroylquinic acids on the polluted but not on the control site. Air pollution seems to be a stress factor for birch trees associated with

  9. Oxidative lime pretreatment of high-lignin biomass: poplar wood and newspaper.

    Science.gov (United States)

    Chang, V S; Nagwani, M; Kim, C H; Holtzapple, M T

    2001-04-01

    Lime (Ca[OH]2) and oxygen (O2) were used to enhance the enzymatic digestibility of two kinds of high-lignin biomass: poplar wood and newspaper. The recommended pretreatment conditions for poplar wood are 150 degrees C, 6 h, 0.1 g of Ca(OH)2/g of dry biomass, 9 mL of water/g of dry biomass, 14.0 bar absolute oxygen, and a particle size of -10 mesh. Under these conditions, the 3-d reducing sugar yield of poplar wood using a cellulase loading of 5 filter paper units (FPU)/g of raw dry biomass increased from 62 to 565 mg of eq. glucose/g of raw dry biomass, and the 3-d total sugar (glucose + xylose) conversion increased from 6 to 77% of raw total sugars. At high cellulase loadings (e.g., 75 FPU/g of raw dry biomass), the 3-d total sugar conversion reached 97%. In a trial run with newspaper, using conditions of 140 degrees C, 3 h, 0.3 g of Ca(OH)2/g of dry biomass, 16 mL of water/g of dry biomass, and 7.1 bar absolute oxygen, the 3-d reducing sugar yield using a cellulase loading of 5 FPU/g of raw dry biomass increased from 240 to 565 mg of eq. glucose/g of raw dry biomass. A material balance study on poplar wood shows that oxidative lime pretreatment solubilized 38% of total biomass, including 78% of lignin and 49% of xylan; no glucan was removed. Ash increased because calcium was incorporated into biomass during the pretreatment. After oxidative lime pretreatment, about 21% of added lime could be recovered by CO2 carbonation.

  10. Direct ethanol production from cellulosic materials by consolidated biological processing using the wood rot fungus Schizophyllum commune.

    Science.gov (United States)

    Horisawa, Sakae; Ando, Hiromasa; Ariga, Osamu; Sakuma, Yoh

    2015-12-01

    In the present study, ethanol production from polysaccharides or wood chips was conducted in a single reactor under anaerobic conditions using the white rot fungus Schizophyllum commune NBRC 4928, which produces enzymes that degrade lignin, cellulose and hemicellulose. The ethanol yields produced from glucose and xylose were 80.5%, and 52.5%, respectively. The absolute yields of ethanol per microcrystalline cellulose (MCC), xylan and arabinogalactan were 0.26g/g-MCC, 0.0419g/g-xylan and 0.0508g/g-arabinogalactan, respectively. By comparing the actual ethanol yields from polysaccharides with monosaccharide fermentation, it was shown that the rate of saccharification was slower than that in fermentation. S. commune NBRC 4928 is concluded to be suitable for CBP because it can produce ethanol from various types of sugar. From the autoclaved cedar chip, only little ethanol was produced by S. commune NBRC 4928 alone but ethanol production was enhanced by combined use of ethanol fermenting and lignin degrading fungi. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Design Wood Nanocomposites from Polymer Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LVWenhua; ZHAOGuangjie

    2004-01-01

    Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect for the development and study of new wood composites with high appending values and multi-properties. This paper reviewed the conventional wood composites, and then discussed the approaches to prepare wood nanocomposites. Based on the achievements of researches on polymer/montmorillonite (MMT) nanocomposites, the design ideas of preparing nanocomposites of wood and inorganic MMT were systematically put forward. Nano compounding of wood and other materials is an effective approach to greatly improve or modify wood.

  12. Ventilation scheme, room location and meteorological factors influence indoor birch pollen concentrations

    Science.gov (United States)

    Jochner, Susanne; Matiu, Michael; Michaelis, Rico; Menzel, Annette

    2017-04-01

    Allergenic pollen, often in co-occurrence with air pollutants from traffic and industries aggravating its pollen allergenicity, constitutes a major health risk for the urban population during the pollen season. Airborne pollen concentrations are traditionally monitored with fixed pollen traps mounted >10 m above ground on flat roof tops. However, the personal exposure of allergic people mostly depends on their main residences and the local emission patterns. Consequently, the assessment of indoor pollen is essential for human health since people stay most of the day inside buildings. In our study, hourly indoor birch pollen concentrations were measured on eight days in April 2015 with portable pollen traps in five rooms of a university building at Freising, Germany. A traditional pollen trap on the roof of the building provided the background birch pollen concentration which was compared to the respective outdoor values right in front of the rooms. The office and lab rooms were characterised by different aspects and window ventilation schemes. Meteorological data were equally measured at a nearby climate station and directly in front of the windows. The observed flowering phenology of 56 birch trees in the nearer surrounding partly explained daily peaks in airborne pollen concentrations. As expected, outdoor pollen concentrations were larger than indoor concentrations: Mean indoor/outdoor (I/O) ratio was highest (0.75) in a south oriented room with fully opened window and additional mechanical ventilation, followed by two rooms with fully opened windows orientated to the west and north (0.35, 0.12) and lowest in east oriented neighbouring rooms with tilted window (0.19) and with windows only opened for short ventilation (0.07). The latter two rooms even had a birch tree directly flowering in front of the façade. Hourly I/O ratios depended on meteorology and increased with outside temperature and wind speed oriented perpendicular to the window opening. As also

  13. Wood gas; Holz gibt Gas

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, Claudia

    2011-06-17

    Sixty years ago, wood gas was even used as a car fuel. Today, this ancient technology is experiencing a renaissance. Small cogeneration plants with wood gasifiers are ideal for renewable and decentral power supply concepts for tomorrow. Until then, there is much pioneering work to do until plants will be ready for serial production.

  14. IMPROVEMENT OF INTERNATIONAL WOOD TRANSPORTATION

    Directory of Open Access Journals (Sweden)

    Sokolov A. P.

    2014-10-01

    Full Text Available The article gives an example of usage of the tool for round-wood transport planning from the Decision Support System “Forest Logistic Toolset” for com-pare of two approaches to the organization of international wood transportation

  15. Assessing potential sustainable wood yield

    Science.gov (United States)

    Robert F. Powers

    2001-01-01

    Society is making unprecedented demands on world forests to produce and sustain many values. Chief among them is wood supply, and concerns are rising globally about the ability of forests to meet increasing needs. Assessing this is not easy. It requires a basic understanding of the principles governing forest productivity: how wood yield varies with tree and stand...

  16. Composites from wood and plastics

    Science.gov (United States)

    Craig Clemons

    2010-01-01

    Composites made from thermoplastics and fillers or reinforcements derived from wood or other natural fibers are a dynamic research area encompassing a wide variety of composite materials. For example, as the use of biopolymers grows, wood and other natural fiber sources are being investigated as renewable sources of fillers and reinforcements to modify performance....

  17. Preservation of forest wood chips

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, P.D.; Thomsen, I.M.; Ohlsson, C.; Leer, E.; Ravn Schmidt, E.; Soerensen, M.; Knudsen, P.

    1999-01-01

    As part of the Danish Energy Research Programme on biomass utilisation for energy production (EFP), this project concerns problems connected to the handling and storing of wood chips. In this project, the possibility of preserving wood chips of the Norway Spruce (Picea Abies) is addressed, and the potential improvements by anaerobic storage are tested. Preservation of wood chips aims at reducing dry matter losses from extensive heating during storage and to reduce production of fungal spores. Fungal spores pose a health hazards to workers handling the chips. Further the producers of wood chips are interested in such a method since it would enable them to give a guarantee for the delivery of homogeneous wood chips also during the winter period. Three different types of wood chips were stored airtight and further one of these was stored in accordance with normal practise and use as reference. The results showed that airtight storage had a beneficial impact on the quality of the chips: no redistribution of moisture, low dry matter losses, unfavourable conditions for microbial activity of most fungi, and the promotion of yeasts instead of fungi with airborne spores. Likewise the firing tests showed that no combustion problems, and no increased risk to the environment or to the health of staff is caused by anaerobic storage of wood chips. In all, the tests of the anaerobic storage method of forest wood chips were a success and a large-scale test of the method will be carried out in 1999. (au)

  18. Moisture transport in coated wood

    NARCIS (Netherlands)

    Meel, P.A. van; Erich, S.J.F.; Huinink, H.P.; Kopinga, K.; Jong, J. DE; Adan, O.C.G.

    2011-01-01

    Moisture accumulation inside wood causes favorable conditions for decay. Application of a coating alters the moisture sorption of wood and prevents accumulation of moisture. This paper presents the results of a nuclear magnetic resonance (NMR) study on the influence of a coating on the moisture abso

  19. Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

    NARCIS (Netherlands)

    Mittag, D.; Akkerdaas, J.; Ballmer-Weber, B.K.; Vogel, L.; Wensing, M.; Becker, W.M.; Koppelman, S.J.; Knulst, A.C.; Helbling, A.; Hefle, S.L.; Ree, R. van; Vieths, S.

    2004-01-01

    We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy. We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1

  20. The safety and efficacy of subcutaneous birch pollen immunotherapy - a one-year, randomised, double-blind, placebo-controlled study

    DEFF Research Database (Denmark)

    Bødtger, Uffe; Poulsen, L K; Jacobi, H H

    2002-01-01

    BACKGROUND: There is only very limited documentation of the efficacy and safety of high-dose subcutaneous birch pollen immunotherapy (IT) in double-blind, placebo-controlled (DBPC) studies. Birch pollen is a major cause of allergic morbidity in northern Europe and in eastern parts of North Americ...

  1. Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

    NARCIS (Netherlands)

    Mittag, D.; Akkerdaas, J.; Ballmer-Weber, B.K.; Vogel, L.; Wensing, M.; Becker, W.M.; Koppelman, S.J.; Knulst, A.C.; Helbling, A.; Hefle, S.L.; Ree, R. van; Vieths, S.

    2004-01-01

    We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy. We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1

  2. The safety and efficacy of subcutaneous birch pollen immunotherapy - a one-year, randomised, double-blind, placebo-controlled study

    DEFF Research Database (Denmark)

    Bødtger, U; Poulsen, Lars K.; Jacobi, H H

    2002-01-01

    There is only very limited documentation of the efficacy and safety of high-dose subcutaneous birch pollen immunotherapy (IT) in double-blind, placebo-controlled (DBPC) studies. Birch pollen is a major cause of allergic morbidity in northern Europe and in eastern parts of North America....

  3. Chain-brush method in delimbing and debarking of wood; Ketjuharja-menetelmae puun karsinnassa ja kuorinnassa

    Energy Technology Data Exchange (ETDEWEB)

    Aho, V.J.; Nikala, L.; Laitinen, H. [VTT Energy, Jyvaeskylae (Finland)

    1997-12-01

    The objective of this project is to study, develop and make an integrated method for production of wood fuels and industrial raw material, promoting the competitiveness of the refining and energy usage of felling residues based on chain-brush delimbing-debarking technology, operational. VTT Energy has tested different brush constructions and the thickness of chains using varying feeding speeds and rotation speeds of the brush-delimber. First thinning pine, spruce and birch have been tested as single trees. Different temperatures have been used in the summer, and frozen timber in the winter. A method has been developed for estimation of the bark content and the wood losses for pine. The method is based on the measurement of the areas covered by bark and the debarked areas of the timber, on the bark thickness values and dry substance content of the wood obtained from the literature, as well as on the calculation formulas obtained from these. Unscrambler software will be used to assist the planning of the tests, and for analysing of the results. The utilisation of the chain-brush method for different wood-species, and the effect of different chain adjustments will be simulated by the software. The chain-brush delimbing will be studied using the high-speed camera acquired to VTT Energy. (orig.)

  4. Elemental analysis of wood materials by external millibeam thick target PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Saarela, K.-E.

    2009-07-01

    PIXE (Particle Induce X-ray Emission spectrometry) was used for analysing stem bark and stem wood of Scots pine, Norway spruce and Silver birch. Thick samples were irradiated, in laboratory atmosphere, with 3 MeV protons and the beam current was measured indirectly using a photo multiplicator (PM) tube. Both point scans and bulk analyses were performed with the 1 mm diameter proton beam. In bulk analyses, whole bark and sectors of discs of the stem wood were dry ashed at 550 deg C. The ashes were homogenised by shaking and prepared to target pellets for PIXE analyses. This procedure generated representative samples to be analysed, but the enrichment also enabled quantification of some additional trace elements. The ash contents obtained as a product of the sample preparation procedure also showed to be of great importance in the evaluation of results in environmental studies. Spot scans from the pith of pine wood outwards, showed clearly highest concentrations of manganese, calcium and zinc in the first spot irradiated, or 2-3 times higher than in the surrounding wood. For stem wood from the crown part of a pine this higher concentration level was found in the first four spots/mms, including the pith and the two following growth rings. Zinc showed increasing concentrations outwards in sapwood of the pine stem, with the over-all lowest concentrations in the inner half of the sapwood. This could indicate emigration of this element from sapwood being under transformation to heartwood. Point scans across sapwood of pine and spruce showed more distinct variations in concentrations relative to hearth wood. Higher concentrations of e.g. zinc, calcium and manganese were found in earlywood than in denser latewood. Very high concentrations of iron and copper were also seen for some earlywood increments. The ash content of stem bark is up to and order higher than for the stem wood. However, when the elemental concentration in ashes of bark and wood of the same disc were

  5. [Biological effect of wood dust].

    Science.gov (United States)

    Maciejewska, A; Wojtczak, J; Bielichowska-Cybula, G; Domańska, A; Dutkiewicz, J; Mołocznik, A

    1993-01-01

    The biological effect of exposure to wood dust depends on its composition and the content of microorganisms which are an inherent element of the dust. The irritant and allergic effects of wood dust have been recognised for a long time. The allergic effect is caused by the wood dust of subtropical trees, e.g. western red cedar (Thuja plicata), redwood (Sequoia sempervirens), obeche (Triplochiton scleroxylon), cocabolla (Dalbergia retusa) and others. Trees growing in the European climate such as: larch (Larix), walnut (Juglans regia), oak (Quercus), beech (Fagus), pine (Pinus) cause a little less pronounced allergic effect. Occupational exposure to irritative or allergic wood dust may lead to bronchial asthma, rhinitis, alveolitis allergica, DDTS (Organic dust toxic syndrome), bronchitis, allergic dermatitis, conjunctivitis. An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed. The highest risk of cancer applies to workers of the furniture industry, particularly those dealing with machine wood processing, cabinet making and carpentry. The cancer of the upper respiratory tract develops after exposure to many kinds of wood dust. However, the wood dust of oak and beech seems to be most carcinogenic. It is assumed that exposure to wood dust can cause an increased incidence of other cancers, especially lung cancer and Hodgkin's disease. The adverse effects of microorganisms, mainly mould fungi and their metabolic products are manifested by alveolitis allergica and ODTS. These microorganisms can induce aspergillomycosis, bronchial asthma, rhinitis and allergic dermatitis.

  6. Utilizing wood wastes as reinforcement in wood cement composite bricks

    Directory of Open Access Journals (Sweden)

    Nusirat Aderinsola Sadiku

    2015-07-01

    Full Text Available This paper presents the research work undertaken to study the properties of Wood Cement Composite Bricks (WCCB from different wood wastes and cement / wood content. The WCBBs with nominal density of 1200 kg m-3 were produced from three tropical wood species and at varying cement and wood content of 2:1, 2.5:1 and 3:1 on a weight to weight basis. The properties evaluated were compressive strength, Ultra Pulse Velocity (UPV, water absorption (WA and thickness swelling (TS. The Compressive strength values ranged from 0.25 to 1.13 N mm-2 and UPV values ranged from 18753 to 49992 m s-1. The mean values of WA after 672 hours (28 days of water soaking of the WCCBs ranged from 9.50% to 47.13% where there were no noticeable change in the TS of the bricks. The observed density (OD ranged from 627 to 1159 kg m-3. A. zygia from the three wood/cement content were more dimensionally stable and better in compressive strength than the other two species where T. scleroxylon had the best performance in terms of UPV. All the properties improved with increasing cement content. WCCBs at 3.0:1 cement/wood content are suitable for structural application such as panelling, ceiling and partitioning

  7. Supplementation with xylanase and β-xylosidase to reduce xylo-oligomer and xylan inhibition of enzymatic hydrolysis of cellulose and pretreated corn stover

    Directory of Open Access Journals (Sweden)

    Qing Qing

    2011-06-01

    Full Text Available Abstract Background Hemicellulose is often credited with being one of the important physical barriers to enzymatic hydrolysis of cellulose, and acts by blocking enzyme access to the cellulose surface. In addition, our recent research has suggested that hemicelluloses, particularly in the form of xylan and its oligomers, can more strongly inhibit cellulase activity than do glucose and cellobiose. Removal of hemicelluloses or elimination of their negative effects can therefore become especially pivotal to achieving higher cellulose conversion with lower enzyme doses. Results In this study, cellulase was supplemented with xylanase and β-xylosidase to boost conversion of both cellulose and hemicellulose in pretreated biomass through conversion of xylan and xylo-oligomers to the less inhibitory xylose. Although addition of xylanase and β-xylosidase did not necessarily enhance Avicel hydrolysis, glucan conversions increased by 27% and 8% for corn stover pretreated with ammonia fiber expansion (AFEX and dilute acid, respectively. In addition, adding hemicellulase several hours before adding cellulase was more beneficial than later addition, possibly as a result of a higher adsorption affinity of cellulase and xylanase to xylan than glucan. Conclusions This key finding elucidates a possible mechanism for cellulase inhibition by xylan and xylo-oligomers and emphasizes the need to optimize the enzyme formulation for each pretreated substrate. More research is needed to identify advanced enzyme systems designed to hydrolyze different substrates with maximum overall enzyme efficacy.

  8. Engineering of the gut commensal bacterium Bacteroides ovatus to produce and secrete biologically active murine interleukin-2 in response to xylan.

    Science.gov (United States)

    Farrar, M D; Whitehead, T R; Lan, J; Dilger, P; Thorpe, R; Holland, K T; Carding, S R

    2005-01-01

    The aim of this work was to engineer a gut commensal bacterium, Bacteroidesovatus, to produce and secrete a biologically active cytokine in a regulated manner as a basis for novel immunotherapies for chronic gut disorders. Bacteroides ovatus was engineered to produce murine interleukin-2 (MuIL2) intracellularly in response to xylan in culture media by inserting the MuIL2 gene into the xylanase operon of the organism. A second strain was engineered to secrete MuIL2 by adding Bacteroides fragilis enterotoxin secretion signal sequence to the protein. The recombinant strains produced MuIL2 only in the presence of xylan as determined by ELISA of cell lysates and culture supernatants. The IL2-dependent cell line CTLL-2 was used to demonstrate that MuIL2 produced by both B. ovatus strains was biologically active. This activity could be blocked by an anti-IL2 neutralizing antibody. The xylan-inducible nature of this system was demonstrated by RT-PCR. Bacteroides ovatus was successfully engineered to produce and secrete biologically active MuIL2 in a xylan-inducible manner. The production and secretion of a biologically active mammalian protein by a member of the gut microflora could lead to the development of new long-term immunotherapies for inflammatory gut diseases.

  9. Bioconversion of xylan for drugs, energy and chemical intermediates%木聚糖生物转化药物、能源和化工中间体

    Institute of Scientific and Technical Information of China (English)

    王海洪; 孙晓锋; 吴耀国

    2011-01-01

    Xylan, the second most abundant polysaccharide compared to cellulose,is a kind of polysaccharide widely existing in the nature. It has tremendous potential applications in many fields, especially in the pharmaceutical,energy and chemicals. Bioconversion with advantages of non-polluting and low-energy consumption expands the applications of xylan. The structure of xylan and itS mechanism of enzymatic lycosylation are introduced. The research on bioconversion of xylan into drugs ( xylo-oligosaccharides and xylitol) , energy ( fuel ethanol and 2, 3-butanediol) , and chemical intermediates ( lactic acid and furfural) are described in detail. Enzymatic species , hacteria , zymotic factors and detective methods are comparably studied as well.%介绍了木聚糖的结构与酶糖化机理,综述了国内外对木聚糖生物转化方面的研究.详细介绍了木聚糖转化为低聚木糖和木糖醇等医药食品、燃料乙醇和2,3-丁二醇等能源物质、乳酸和糠醛等化工中间体的研究进展.

  10. A two-stage pretreatment approach to maximise sugar yield and enhance reactive lignin recovery from poplar wood chips.

    Science.gov (United States)

    Panagiotopoulos, I A; Chandra, R P; Saddler, J N

    2013-02-01

    A two-stage pretreatment approach, employing steam followed by organosolv treatment, was assessed for its ability to fractionate and recover most of the hemicellulose, lignin and cellulose components of poplar wood chips. A mild steaming stage was initially used to maximise hemicellulose sugar recovery, with 63% of the original xylan solubilised and recovered after this stage and close to 90% recovered in total. Rather than hindering subsequent organosolv delignification, the prior steam treatment enhanced lignin solubilisation with more than 66% of the original lignin removed after the two-stage pretreatment. The extracted lignin contained at least equal or greater amounts of functional groups as compared to the lignin solubilised after a single-stage organosolv pretreatment. More than 98% of the original cellulose was recovered after the two-stage pretreatment and 88% of the cellulose could be hydrolysed to glucose at enzyme loading of 5FPU/g cellulose after 72h.

  11. Selectivity and delignification kinetics for oxidative and nonoxidative lime pretreatment of poplar wood, part III: long-term.

    Science.gov (United States)

    Sierra, Rocio; Garcia, Laura A; Holtzapple, Mark Thomas

    2010-01-01

    Lime pretreatment is an effective method for improving lignocellulose digestibility by removing lignin. For several weeks, mixtures of poplar wood, water, and calcium hydroxide (lime) were submitted to temperatures from 25 to 65°C, with and without aeration. Kinetic models for lignin and carbohydrate degradation were obtained as functions of temperature, time, and aeration using first-order kinetics in lignin and carbohydrates. Model 1 considered two reacting moieties (slow and fast), and Model 2 considered three (slow, medium, and fast). Model 1 was statistically better and was employed to determine differential and integral selectivities, which measure the ability of pretreatment to retain carbohydrates while removing lignin. During the first 2 weeks, when lignin content ≥ 0.80 g/g lignin in raw biomass, both glucan and xylan differential and integral selectivities decreased rapidly. Afterwards, selectivities were nearly constant ranging between 0 and 3 g lignin removed/g carbohydrate degraded.

  12. Moth outbreaks alter root-associated fungal communities in subarctic mountain birch forests.

    Science.gov (United States)

    Saravesi, Karita; Aikio, Sami; Wäli, Piippa R; Ruotsalainen, Anna Liisa; Kaukonen, Maarit; Huusko, Karoliina; Suokas, Marko; Brown, Shawn P; Jumpponen, Ari; Tuomi, Juha; Markkola, Annamari

    2015-05-01

    Climate change has important implications on the abundance and range of insect pests in forest ecosystems. We studied responses of root-associated fungal communities to defoliation of mountain birch hosts by a massive geometrid moth outbreak through 454 pyrosequencing of tagged amplicons of the ITS2 rDNA region. We compared fungal diversity and community composition at three levels of moth defoliation (intact control, full defoliation in one season, full defoliation in two or more seasons), replicated in three localities. Defoliation caused dramatic shifts in functional and taxonomic community composition of root-associated fungi. Differentially defoliated mountain birch roots harbored distinct fungal communities, which correlated with increasing soil nutrients and decreasing amount of host trees with green foliar mass. Ectomycorrhizal fungi (EMF) abundance and richness declined by 70-80 % with increasing defoliation intensity, while saprotrophic and endophytic fungi seemed to benefit from defoliation. Moth herbivory also reduced dominance of Basidiomycota in the roots due to loss of basidiomycete EMF and increases in functionally unknown Ascomycota. Our results demonstrate the top-down control of belowground fungal communities by aboveground herbivory and suggest a marked reduction in the carbon flow from plants to soil fungi following defoliation. These results are among the first to provide evidence on cascading effects of natural herbivory on tree root-associated fungi at an ecosystem scale.

  13. NMR resonance assignments of a hypoallergenic isoform of the major birch pollen allergen Bet v 1.

    Science.gov (United States)

    Ahammer, Linda; Grutsch, Sarina; Wallner, Michael; Ferreira, Fatima; Tollinger, Martin

    2017-08-14

    In Northern America and Europe a great number of people are suffering from birch pollen allergy and pollen related food allergies. The trigger for these immunological reactions is the 17.5 kDa major birch pollen allergen Bet v 1, which belongs to the family of PR-10 (pathogenesis-related) proteins. In nature, Bet v 1 occurs as a mixture of various isoforms that possess different immunological properties despite their high sequence identities. Bet v 1.0102 (Bet v 1d), which is investigated here, is a hypoallergenic isoform of Bet v 1 and a potential candidate for allergen-specific immunotherapy. We assigned the backbone and side chain (1)H, (13)C and (15)N resonances of this protein and predicted its secondary structure. The NMR-chemical shift data indicate that Bet v 1.0102 is composed of three α-helices and a seven stranded β-sheet, in agreement with the known structure of the hyperallergenic isoform Bet v 1.0101 (Bet v 1a). Our resonance assignments create the foundation for detailed characterization of the dynamic properties of Bet v 1 isoforms by NMR relaxation measurements.

  14. Synthesis and characterization of bagasse xylan phosphate%蔗渣木聚糖磷酸酯的合成与表征

    Institute of Scientific and Technical Information of China (English)

    李和平; 李东旭; 鲁勇

    2011-01-01

    Bagasse xylan phosphate was synthesized by using bagasse xylan as raw materials,NaH2PO4 and Na2HPO4 as esterifying agent,urea as catalyst under the wet process,The influence of reaction conditions on the degree of substitution was investigated, such as reactic temperature, reaction time, xylan and esterifying agent ratio, xylan and catalyst ratio, reaction pH and so on. Synthesis conditions was systematically investigated adopted to orthogonal experimental design,and statistical analysis was used to research the orders and significance of various factors. The optimal conditions are reaction temperature 55℃,reaction time Sh, mxylan:m催化剂=4:l. 20、mxylan:m催化剂=4:0.50,pH=5. 5. The DS of bagasse xylan phosphate was obtained as 0.067. The structure and particle shape of the bagasse xylan phosphate were characterizated by FTIR and SEM .Thermal analysis showed that the thermal stability of bagasse xylan phosphate reduced.%以蔗渣木聚糖为主要原料,正磷酸盐(NaH2PO4与Na2 HPO4)为酯化剂,尿素为催化剂,在湿法工艺下合成了蔗渣木聚糖磷酸酯.考察了酯化温度、酯化时间、蔗渣木聚糖与酯化剂和催化剂配比、pH等因素对取代度的影响,采用正交试验设计对合成条件进行优化,运用统计分析方法探讨了各因素影响的主次顺序和显著性,得到较佳的合成条件为:酯化温度55℃、酯化时间=5h、mxylan:m酯化剂=4:1.20、mxlan:m催化剂=4:0.50、pH=5.5,所得产物的取代度为0.067.用FTIR和SEM对蔗渣木聚糖磷酸酯的结构和形貌进行了表征,热分析表明蔗渣木聚糖磷酸酯热稳定性降低.

  15. Non_standard Wood

    DEFF Research Database (Denmark)

    Tamke, Martin

    Non-Standard elements in architecture bear the promise of a better more specific performance (Oosterhuis 2003). A new understanding of design evolves, which is focusing on open ended approaches, able to negotiate between shifting requirements and to integrate knowledge on process and material......- and machine industry we fabricated a 1:1 demonstrator show casing the potential for performance due to digital fabrication in this sustainable material. The production of a custom made design tool helped not only to explore design variations while keeping up the link to digital production machinery....... Using parametric design tools and computer controlled production facilities Copenhagens Centre for IT and Architecture undertook a practice based research into performance based non-standard element design and mass customization techniques. In close cooperation with wood construction software...

  16. Cooling of wood briquettes

    Directory of Open Access Journals (Sweden)

    Adžić Miroljub M.

    2013-01-01

    Full Text Available This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C.

  17. Fire Safety Design of Wood Structures

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2006-01-01

    Lecture Notes on Fire Safety Design of Wood Structures including charring of wood and load bearing capacity of beams, columns, and connections.......Lecture Notes on Fire Safety Design of Wood Structures including charring of wood and load bearing capacity of beams, columns, and connections....

  18. Bioprocessing preservative-treated waste wood

    Science.gov (United States)

    Barbara L. Illman; Vina W. Yang; Les. Ferge

    2000-01-01

    Disposal of preservative-treated waste wood is a growing problem worldwide. Bioprocessing the treated wood offers one approach to waste management under certain conditions. One goal is to use wood decay fungi to reduce the volume of waste with an easily managed system in a cost-effective manner. Wood decay fungi were obtained from culture collections in the Mycology...

  19. Wood Technology: Techniques, Processes, and Products

    Science.gov (United States)

    Oatman, Olan

    1975-01-01

    Seven areas of wood technology illustrates applicable techniques, processes, and products for an industrial arts woodworking curriculum. They are: wood lamination; PEG (polyethylene glycol) diffusion processes; wood flour and/or particle molding; production product of industry; WPC (wood-plastic-composition) process; residential construction; and…

  20. FIRE INSURANCE AND WOOD SCHOOL BUILDINGS.

    Science.gov (United States)

    PURCELL, FRANK X.

    A COMPARISON OF FIRE INSURANCE COSTS OF WOOD, MASONRY, STEEL AND CONCRETE STRUCTURES SHOWS FIRE INSURANCE PREMIMUMS ON WOOD STRUCTURES TEND TO BE HIGHER THAN PREMIUMS ON MASONRY, STEEL AND CONCRETE BUILDINGS, HOWEVER, THE INITIAL COST OF THE WOOD BUILDINGS IS LOWER. DATA SHOW THAT THE SAVINGS ACHIEVED IN THE INITIAL COST OF WOOD STRUCTURES OFFSET…

  1. Study on extraction of xylan from corn cob with alkaline solution%玉米芯中木聚糖的碱法提取研究

    Institute of Scientific and Technical Information of China (English)

    汤卫华; 龙尾; 吕春晖

    2014-01-01

    木聚糖是存在于植物细胞壁中的重要聚合糖,玉米芯是木聚糖含量较高的农业纤维废弃物。采用不同的碱性物质对玉米芯中木聚糖进行提取,结果发现NaOH更适合木聚糖的提取。NaOH碱液提取木糖醇的最适提取条件为:NaOH浓度2.5 mol/L,料液比1 g∶10 mL,115℃提取60 min。在此条件下,木聚糖的提取率达到23.5%,该方法具有较高的应用价值。%Xylan is an important polymeric sugar in plant cell wall;corn cob is an agricultural fiber waste containing higher xylan content. Three alkaline solutions were used to extract xylan from corn cob, it was found that NaOH solution was more suitable for the extraction of xylan. The optimal extraction factors were showed that NaOH solution was 2.5 mol/L, solid-liquid ratio was 1 g∶10 mL,extraction temperature was 115℃and extraction time was 60 min. Under the above conditions, the yield of xylan was up to 23.5%.

  2. Potential wood protection strategies using physiological requirements of wood degrading fungi

    NARCIS (Netherlands)

    Sailer, M.F.; Etten, B.D. van

    2004-01-01

    Due to the increasing restrictions in the use of wood preserving biocides a number of potential biocide free wood preserving alternatives are currently assessed. Wood degrading fungi require certain conditions in the wood in order to be able to use wood as a food source. This paper discusses the phy

  3. RHEOLOGICAL BEHAVIOR OF WOOD AND WOOD BASED MATERIALS

    Directory of Open Access Journals (Sweden)

    Rafael Rodolfo de Melo

    2010-05-01

    Full Text Available The wood, as well as other construction materials, presents changes in this stiffness and strength when submitted to a long time loading. This phenomenon is important in the analyses resistance capacity of structural materials. Mechanically, the wood behaves as aviscous-elastic solid. However, over time, the structural elements submitted to permanent or cyclic loading presents some deformation, which denotes a viscous-elastic behavior. This characteristic is influenced mainly on the intensity and duration of loading. In this study a review of rheological phenomenon is presented, showing up the causes and effects for a better understanding, which is essential for the appropriate and efficient use of the wood and wood composites as structural materials.

  4. COMBUSTION PROPERTIES OF EUCALYPTUS WOOD

    Directory of Open Access Journals (Sweden)

    Yalçın ÖRS

    1999-03-01

    Full Text Available In this study, the combustion properties of some impregnation materials (abiotic and biotic factors used for eucalyptus wood in interior or exterior environments were investigated. The experimental samples were prepared from Eucalyptus wood based on ASTM-D-1413-76 Tanalith-CBC, boric acid, borax, vacsol-WR, immersol-WR, polyethylen glycole-400 and ammonium sulphate were used as an impregnation material. The results indicated that, vacuum treatment on Eucalyptus gave the lowest retention value of salts. Compounds containing boron+salt increased fire resistance however water repellents decreased the wood flammability.

  5. Ground Wood Fiber Length Distributions

    Directory of Open Access Journals (Sweden)

    Lauri Ilmari Salminen

    2014-01-01

    Full Text Available This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results.

  6. A CONTINUING REVERENCE FOR WOOD

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2010-02-01

    Full Text Available Our ancestors knew a great deal about wood. They had to in order to do well in life. Wood has played a dominant role in human infrastructure for many generations, and for most of that time woodcraft has depended on the decentralized knowledge passed down among families and guilds. This editorial, while celebrating the knowledge, skills, and insights of the woodworkers of past generations, also calls for a renewed attention to wood’s unique character, including characteristics that today are too often classified as “defects.” We may need to take lessons from generations past to truly derive the best value from wood resources.

  7. How the user can influence particulate emissions from residential wood and pellet stoves: Emission factors for different fuels and burning conditions

    Science.gov (United States)

    Fachinger, Friederike; Drewnick, Frank; Gieré, Reto; Borrmann, Stephan

    2017-06-01

    For a common household wood stove and a pellet stove we investigated the dependence of emission factors for various gaseous and particulate pollutants on burning phase, burning condition, and fuel. Ideal and non-ideal burning conditions (dried wood, under- and overload, small logs, logs with bark, excess air) were used. We tested 11 hardwood species (apple, ash, bangkirai, birch, beech, cherry, hickory, oak, olive, plum, sugar maple), 4 softwood species (Douglas fir, pine, spruce, spruce/fir), treated softwood, beech and oak wood briquettes, paper briquettes, brown coal, wood chips, and herbaceous species (miscanthus, Chinese silver grass) as fuel. Particle composition (black carbon, non-refractory, and some semi-refractory species) was measured continuously. Repeatability was shown to be better for the pellet stove than for the wood stove. It was shown that the user has a strong influence on wood stove emission behavior both by selection of the fuel and of the burning conditions: Combustion efficiency was found to be low at both very low and very high burn rates, and influenced particle properties such as particle number, mass, and organic content in a complex way. No marked differences were found for the emissions from different wood species. For non-woody fuels, much higher emission factors could be observed (up to five-fold increase). Strongest enhancement of emission factors was found for burning of small or dried logs (up to six-fold), and usage of excess air (two- to three-fold). Real world pellet stove emissions can be expected to be much closer to laboratory-derived emission factors than wood stove emissions, due to lower dependence on user operation.

  8. Xylan-binding xylanase Xyl30 from Streptomyces avermitilis: cloning, characterization, and overproduction in solid-state fermentation.

    Science.gov (United States)

    Hernández, Alberto; López, José C; Santamaría, Ramón; Díaz, Margarita; Fernández-Abalos, José M; Copa-Patiño, José L; Soliveri, Juan

    2008-06-01

    A DNA fragment from the lignocellulolytic actinomycete Streptomyces avermitilis CECT 3339 was cloned using a DNA probe from the xylanase gene xysA of Streptomyces halstedii. The nucleotide sequence analysis revealed two potential ORFs, xyl30 and hd30, encoding a deduced multimodular F/10 xylanase with a binding domain and a secreted glycoxyl hydrolase, respectively. In Streptomyces lividans carrying the subcloned DNA fragment, two xylanase activity bands with estimated molecular masses of 42.8 and 35 kDa (named Xyl30 forms "h" and "l", respectively), were detected by zymograms and SDS-PAGE. The two xylanases had identical N-terminal sequences, suggesting that Xyl30 "l" derived from Xyl30 "h" by C-terminal processing in the culture supernatant. No transcripts of hd30 were detected by RT-PCR. Characterization of the partially purified Xyl30 "h" confirmed the presence of a modular endoxylanase containing a xylan-binding domain, which after processing in the culture supernatant loses the aforementioned domain and thus its capacity to bind xylan (Xyl30 "l"). Xyl30 "h" achieved maximal activity at pH 7.5 and 60 degrees C, retaining more than 50% of its activity from pH 3 to 9 and more than 40% after a 1-h incubation at 70 masculineC. Moreover, in the recombinant host strain up to 400 U xylanase/g medium (dry weight) was produced in solid-state fermentation (SSF) using cereal bran as substrate. The high production yields of this enzyme and its biochemical features make it a good candidate for use in industrial applications.

  9. An eleven amino acid residue deletion expands the substrate specificity of acetyl xylan esterase II (AXE II) from Penicillium purpurogenum

    Science.gov (United States)

    Colombres, Marcela; Garate, José A.; Lagos, Carlos F.; Araya-Secchi, Raúl; Norambuena, Patricia; Quiroz, Soledad; Larrondo, Luis; Pérez-Acle, Tomas; Eyzaguirre, Jaime

    2008-01-01

    The soft-rot fungus Penicillium purpurogenum secretes to the culture medium a variety of enzymes related to xylan biodegradation, among them three acetyl xylan esterases (AXE I, II and III). AXE II has 207 amino acids; it belongs to family 5 of the carbohydrate esterases and its structure has been determined by X-ray crystallography at 0.9 Å resolution (PDB 1G66). The enzyme possesses the α/β hydrolase fold and the catalytic triad typical of serine esterases (Ser90, His187 and Asp175). AXE II can hydrolyze esters of a large variety of alcohols, but it is restricted to short chain fatty acids. An analysis of its three-dimensional structure shows that a loop that covers the active site may be responsible for this strict specificity. Cutinase, an enzyme that hydrolyzes esters of long chain fatty acids and shows a structure similar to AXE II, lacks this loop. In order to generate an AXE II with this broader specificity, the preparation of a mutant lacking residues involving this loop (Gly104 to Ala114) was proposed. A set of molecular simulation experiments based on a comparative model of the mutant enzyme predicted a stable structure. Using site-directed mutagenesis, the loop's residues have been eliminated from the AXE II cDNA. The mutant protein has been expressed in Aspergillus nidulans A722 and Pichia pastoris, and it is active towards a range of fatty acid esters of up to at least 14 carbons. The availability of an esterase with broader specificity may have biotechnological applications for the synthesis of sugar esters.

  10. Xylan utilization in human gut commensal bacteria is orchestrated by unique modular organization of polysaccharide-degrading enzymes

    KAUST Repository

    Zhang, Meiling

    2014-08-18

    Enzymes that degrade dietary and host-derived glycans represent the most abundant functional activities encoded by genes unique to the human gut microbiome. However, the biochemical activities of a vast majority of the glycan-degrading enzymes are poorly understood. Here, we use transcriptome sequencing to understand the diversity of genes expressed by the human gut bacteria Bacteroides intestinalis and Bacteroides ovatus grown in monoculture with the abundant dietary polysaccharide xylan. The most highly induced carbohydrate active genes encode a unique glycoside hydrolase (GH) family 10 endoxylanase (BiXyn10A or BACINT-04215 and BACOVA-04390) that is highly conserved in the Bacteroidetes xylan utilization system. The BiXyn10A modular architecture consists of a GH10 catalytic module disrupted by a 250 amino acid sequence of unknown function. Biochemical analysis of BiXyn10A demonstrated that such insertion sequences encode a new family of carbohydrate-binding modules (CBMs) that binds to xy-lose- configured oligosaccharide/polysaccharide ligands, the substrate of the BiXyn10A enzymatic activity. The crystal structures of CBM1 from BiXyn10A (1.8 Å), a cocomplex of BiXyn10A CBM1 with xylohexaose (1.14 Å), and the CBM fromits homolog in the Prevotella bryantii B 14 Xyn10C (1.68 Å) reveal an unanticipated mode for ligand binding. Aminimal enzyme mix, composed of the gene products of four of the most highly up-regulated genes during growth on wheat arabinoxylan, depolymerizes the polysaccharide into its component sugars. The combined biochemical and biophysical studies presented here provide a framework for understanding fiber metabolism by an important group within the commensal bacterial population known to influence human health.

  11. UDP-Xylose-stimulated glucuronyltransferase activity in wheat microsomal membranes: characterization and role in glucurono(arabino)xylan biosynthesis.

    Science.gov (United States)

    Zeng, Wei; Chatterjee, Mohor; Faik, Ahmed

    2008-05-01

    Microsomal membranes from etiolated wheat (Triticum aestivum) seedlings cooperatively incorporated xylose (Xyl), arabinose, and glucuronic acid residues from their corresponding uridine 5'-diphosphosugars into an ethanol-insoluble glucurono(arabino)xylan (GAX)-like product. A glucuronyltransferase activity that is enhanced by the presence of UDP-Xyl was also identified in these microsomes. Wheat glucuronyltransferase activity was optimal at pH 7 and required manganese ions, and several lines of evidence suggest its involvement in GAX-like biosynthesis. The GAX characteristics of the 14C-product were confirmed by digestion with a purified endo-xylanase from Aspergillus awamori (endo-xylanase III) and by total acid hydrolysis, resulting in a Xyl:arabinose:glucuronic acid molar ratio of approximately 105:34:1. Endo-xylanase III released only three types of oligosaccharides in addition to free Xyl. No radiolabel was released as xylobiose, xylotriose, or xylotetraose, indicating the absence of long stretches of unbranched Xyl residues in the nascent GAX-like product. High-pH anion exchange chromatography analysis of the resulting oligosaccharides along with known arabinoxylan oligosaccharide standards suggests that a portion of the nascent GAX-like product has a relatively regular structure. The other portion of the [14C]GAX-like polymer was resistant to proteinase K, endo-polygalacturonase, and endo-xylanase III (GH11 family) but was degraded by Driselase, supporting the hypothesis that the xylan backbone in this portion of the product is most likely highly substituted. Size exclusion chromatography indicated that the nascent GAX-like polymer had an apparent molecular mass of approximately 10 to 15 kD; however, mature GAXs from wheat cell walls had larger apparent molecular masses (>66 kD).

  12. Prospect for Developing a Consolidated Bioprocessing (CBP) Strain Using Xylan as the Substrate: the Case Study of Yarrowia lipolytica

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Wei, Hui; Alahuhta, Markus; Zhang, Min; Himmel, Michael E.

    2016-07-08

    To achieve the goal of developing a direct microbial sugar conversion platform for the production of lipids and drop-in fuels from cellulosic biomass substrate, Yarrowia lipolytica was used to investigate its potential for being developed as CBP strain by expressing cellulase and xylanase enzymes. Y. lipolytica is known to accumulate lipids intracellularly and is capable of metabolizing glucose and xylose to produce lipids; however, due to the lack of the biomass degrading enzymes, it cannot directly utilize lignocellulosic substrates as carbon sources. While research is continuing on the development of a Y. lipolytica strain able to degrade cellulose, in this study, we present successful expression of several xylanases in Y. lipolytica. To the best of our knowledge, this is the first study introducing heterologous hemicellulose genes into the genome of Y. lipolytica. SDS-PAGE and western blotting analysis showed that the endo-xylanase gene XynII and exo-xylosidase gene XlnD were successfully expressed and secreted, and the expressed xylanases were likely either not or sparsely glycosylated, which is advantageous for expression of heterologous proteins from any species. Enzymatic activity tests further demonstrated active expression of XynII and XlnD in Y. lipolytica. Furthermore, synergistic action on converting xylan to xylose was observed when XlnD worked in concert with XynII. XlnD was able to work on the xylo-oligomers generated by XynII, enhancing the xylan conversion to monomeric xylose. The successful expression of these xylanases in Yarrowia further advances us towards our goal to develop a direct microbial conversion process using this organism. and xylose to produce lipids; however, due to the lack of the biomass degrading enzymes, it cannot directly utilize lignocellulosic substrates as carbon sources. While research is continuing on the development of a Y. lipolytica strain able to degrade cellulose, in this study, we present successful expression of

  13. Seven different genes encode a diverse mixture of isoforms of Bet v 1, the major birch pollen allergen

    NARCIS (Netherlands)

    Schenk, M.F.; Gilissen, L.J.W.J.; Esselink, G.D.; Smulders, M.J.M.

    2006-01-01

    Background: Pollen of the European white birch (Betula pendula, syn. B. verrucosa) is an important cause of hay fever. The main allergen is Bet v 1, member of the pathogenesis-related class 10 (PR-10) multigene family. To establish the number of PR-10/Bet v 1 genes and the isoform diversity within a

  14. Birch Bark Dry Extract by Supercritical Fluid Technology: Extract Characterisation and Use for Stabilisation of Semisolid Systems

    Directory of Open Access Journals (Sweden)

    Markus Armbruster

    2017-03-01

    Full Text Available Triterpene compounds like betulin, betulinic acid, erythrodiol, oleanolic acid and lupeol are known for many pharmacological effects. All these substances are found in the outer bark of birch. Apart from its pharmacological effects, birch bark extract can be used to stabilise semisolid systems. Normally, birch bark extract is produced for this purpose by extraction with organic solvents. Employing supercritical fluid technology, our aim was to develop a birch bark dry extract suitable for stabilisation of lipophilic gels with improved properties while avoiding the use of toxic solvents. With supercritical carbon dioxide, three different particle formation methods from supercritical solutions have been tested. First, particle deposition was performed from a supercritical solution in an expansion chamber. Second, the Rapid Expansion of Supercritical Solutions (RESS method was used for particle generation. Third, a modified RESS-procedure, forming the particles directly into the thereby gelated liquid, was developed. All three methods gave yields from 1% to 5.8%, depending on the techniques employed. The triterpene composition of the three extracts was comparable: all three gave more stable oleogels compared to the use of an extract obtained by organic solvent extraction. Characterizing the rheological behaviour of these gels, a faster gelling effect was seen together with a lower concentration of the extract required for the gel formation with the supercritical fluid (SCF-extracts. This confirms the superiority of the supercritical fluid produced extracts with regard to the oleogel forming properties.

  15. Did the iceman know better? Screening of the medicinal properties of the birch polypore medicinal mushroom, piptoporus betulinus (higher basidiomycetes)

    NARCIS (Netherlands)

    Vunduk, Jovana; Klaus, Anita; Kozarski, Maja; Petrović, Predrag; Žižak, Željko; Nikšić, Miomir; Griensven, Van L.J.L.D.

    2015-01-01

    The birch polypore Piptoporus betulinus was among two mushrooms that were found in the Iceman’s bag. Recent studies indicated that P. betulinus was probably used as a religious and medicinal item. In order to examine the medicinal potential of P. betulinus, hot water (HW), partially purified

  16. Assessing the Potential Stem Growth and Quality of Yellow Birch Prior to Restoration: A Case Study in Eastern Canada

    Directory of Open Access Journals (Sweden)

    Alexis Achim

    2013-09-01

    Full Text Available Past silvicultural treatments have resulted in the high-grading mixed temperate forests of Québec, Canada. Despite recognition of this issue, the low occurrence of yellow birch (Betula alleghaniensis Britton within current stands raises questions about the potential of the species to grow and eventually constitute a high-quality forest resource. The objective of this study was to assess this potential using tree characteristics, forest structure and additional site and climatic conditions as predictors. A total of 145 trees were sampled in two areas located in the same bioclimatic zone. Lower-Saguenay-Charlevoix was chosen as an area where a restoration plan could be implemented, whereas Portneuf was selected as a reference. We used nonlinear mixed models to investigate which environmental factors are likely to influence the radial growth and stem quality of yellow birch sample trees. Our results suggest that topographic and climatic conditions, as well as the competitive environment of the trees, are important factors to consider in the evaluation of yellow birch production. Despite the limited occurrence of yellow birch, the potential for growth and quality was high in the Lower-Saguenay-Charlevoix area. For equivalent topographic, climatic, and competitive environment conditions, there was no significant difference in either radial growth or stem quality with Portneuf. We suggest that the economic interest of producing high quality timber should be used to justify the implementation of a restoration strategy in the Lower-Saguenay-Charlevoix area.

  17. The influence of lathe check depth and orientation on the bond quality of phenol-formaldehyde-bonded birch plywood

    Science.gov (United States)

    Anti Rohumaa; Christopher G. Hunt; Mark Hughes; Charles R. Frihart; Janne Logren

    2013-01-01

    During the rotary peeling of veneer for plywood or the laminated veneer lumber manufacture, checks are formed in the veneer that are as deep as 70 – 80 % of the veneer thickness. The results of this study show that, during adhesive bond testing, deep lathe checks in birch (Betula pendula Roth.) veneer significantly reduce the shear strength and the...

  18. Influence of Nitrogen Availability on Growth of Two Transgenic Birch Species Carrying the Pine GS1a Gene

    Directory of Open Access Journals (Sweden)

    Vadim G. Lebedev

    2017-01-01

    Full Text Available An alternative way to increase plant productivity through the use of nitrogen fertilizers is to improve the efficiency of nitrogen utilization via genetic engineering. The effects of overexpression of pine glutamine synthetase (GS gene and nitrogen availability on growth and leaf pigment levels of two Betula species were studied. Untransformed and transgenic plants of downy birch (B. pubescens and silver birch (B. pendula were grown under open-air conditions at three nitrogen regimes (0, 1, or 10 mM for one growing season. The transfer of the GS1a gene led to a significant increase in the height of only two transgenic lines of nine B. pubescens, but three of five B. pendula transgenic lines were higher than the controls. In general, nitrogen supply reduced the positive effect of the GS gene on the growth of transgenic birch plants. No differences in leaf pigment levels between control and transgenic plants were found. Nitrogen fertilization increased leaf chlorophyll content in untransformed plants but its effect on most of the transgenic lines was insignificant. The results suggest that birch plants carrying the GS gene use nitrogen more efficiently, especially when growing in nitrogen deficient soil. Transgenic lines were less responsive to nitrogen supply in comparison to wild-type plants.

  19. An investigation of the possible immunological relationship between allergen extracts from birch pollen, hazelnut, potato and apple

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Løwenstein, H

    1978-01-01

    In a retrospective study on selected group of patients, the coincidence of birch pollen allergy and a clinically relevant positive prick test reaction to apples and potatoes was confirmed. Immunochemical comparison using the crossed line immunoelectrophoresis technique (CLIE) confirmed partial id...

  20. Influence of Nitrogen Availability on Growth of Two Transgenic Birch Species Carrying the Pine GS1a Gene

    Science.gov (United States)

    Lebedev, Vadim G.; Kovalenko, Nina P.; Shestibratov, Konstantin A.

    2017-01-01

    An alternative way to increase plant productivity through the use of nitrogen fertilizers is to improve the efficiency of nitrogen utilization via genetic engineering. The effects of overexpression of pine glutamine synthetase (GS) gene and nitrogen availability on growth and leaf pigment levels of two Betula species were studied. Untransformed and transgenic plants of downy birch (B. pubescens) and silver birch (B. pendula) were grown under open-air conditions at three nitrogen regimes (0, 1, or 10 mM) for one growing season. The transfer of the GS1a gene led to a significant increase in the height of only two transgenic lines of nine B. pubescens, but three of five B. pendula transgenic lines were higher than the controls. In general, nitrogen supply reduced the positive effect of the GS gene on the growth of transgenic birch plants. No differences in leaf pigment levels between control and transgenic plants were found. Nitrogen fertilization increased leaf chlorophyll content in untransformed plants but its effect on most of the transgenic lines was insignificant. The results suggest that birch plants carrying the GS gene use nitrogen more efficiently, especially when growing in nitrogen deficient soil. Transgenic lines were less responsive to nitrogen supply in comparison to wild-type plants. PMID:28067821

  1. Academic Success for Students of Color . . . At What Cost? The Importance of School Context at Birch High School

    Science.gov (United States)

    Chambers, Terah T. Venzant; Tabron, Lolita A.

    2013-01-01

    Kiara, an African American rising freshman, has aspirations to become a medical doctor. She enrolls at Birch High School because of the reputation of the principal, Mr. Brown, whose vision for academic excellence permeates every corner of the school. Kiara graduates from high school with top honors, but realizes her success may have come at a…

  2. Academic Success for Students of Color . . . At What Cost? The Importance of School Context at Birch High School

    Science.gov (United States)

    Chambers, Terah T. Venzant; Tabron, Lolita A.

    2013-01-01

    Kiara, an African American rising freshman, has aspirations to become a medical doctor. She enrolls at Birch High School because of the reputation of the principal, Mr. Brown, whose vision for academic excellence permeates every corner of the school. Kiara graduates from high school with top honors, but realizes her success may have come at a…

  3. Purification and characterization of natural Bet v 1 from birch pollen and related allergens from carrot and celery

    NARCIS (Netherlands)

    Bollen, M.A.; Garcia, A.; Cordewener, J.H.G.; Wichers, H.J.; Helsper, J.P.F.G.; Savelkoul, H.F.J.; Boekel, van M.A.J.S.

    2007-01-01

    Birch pollen allergy is predominantly caused by the major allergen Bet v 1 and can lead to crossreactions with homologous proteins in food. Two major cross-reactive food allergens are Dau c 1 from carrot and Api g 1 from celery, which have never been purified from their natural source. Here, we desc

  4. Seven different genes encode a diverse mixture of isoforms of Bet v 1, the major birch pollen allergen

    NARCIS (Netherlands)

    Schenk, M.F.; Gilissen, L.J.W.J.; Esselink, G.D.; Smulders, M.J.M.

    2006-01-01

    Background: Pollen of the European white birch (Betula pendula, syn. B. verrucosa) is an important cause of hay fever. The main allergen is Bet v 1, member of the pathogenesis-related class 10 (PR-10) multigene family. To establish the number of PR-10/Bet v 1 genes and the isoform diversity within a

  5. An investigation of the possible immunological relationship between allergen extracts from birch pollen, hazelnut, potato and apple

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Løwenstein, H

    1978-01-01

    In a retrospective study on selected group of patients, the coincidence of birch pollen allergy and a clinically relevant positive prick test reaction to apples and potatoes was confirmed. Immunochemical comparison using the crossed line immunoelectrophoresis technique (CLIE) confirmed partial id...

  6. Purification and characterization of natural Bet v 1 from birch pollen and related allergens from carrot and celery

    NARCIS (Netherlands)

    Bollen, M.A.; Garcia, A.; Cordewener, J.H.G.; Wichers, H.J.; Helsper, J.P.F.G.; Savelkoul, H.F.J.; Boekel, van M.A.J.S.

    2007-01-01

    Birch pollen allergy is predominantly caused by the major allergen Bet v 1 and can lead to crossreactions with homologous proteins in food. Two major cross-reactive food allergens are Dau c 1 from carrot and Api g 1 from celery, which have never been purified from their natural source. Here, we desc

  7. Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines.

    Science.gov (United States)

    Sutela, Suvi; Hahl, Terhi; Tiimonen, Heidi; Aronen, Tuija; Ylioja, Tiina; Laakso, Tapio; Saranpää, Pekka; Chiang, Vincent; Julkunen-Tiitto, Riitta; Häggman, Hely

    2014-01-01

    A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

  8. Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines.

    Directory of Open Access Journals (Sweden)

    Suvi Sutela

    Full Text Available A small multigene family encodes 4-coumarate:CoA ligases (4CLs catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1 to the lignin and soluble phenolic compound composition of silver birch (Betula pendula Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S and guaiacyl (G lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1 were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

  9. Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study

    Science.gov (United States)

    The HIALINE working Group; Buters, Jeroen T. M.; Thibaudon, Michel; Smith, Matt; Kennedy, Roy; Rantio-Lehtimäki, Auli; Albertini, Roberto; Reese, Gerald; Weber, Bernhard; Galan, Carmen; Brandao, Rui; Antunes, Celia M.; Jäger, Siegfried; Berger, Uwe; Celenk, Sevcan; Grewling, Łukasz; Jackowiak, Bogdan; Sauliene, Ingrida; Weichenmeier, Ingrid; Pusch, Gudrun; Sarioglu, Hakan; Ueffing, Marius; Behrendt, Heidrun; Prank, Marje; Sofiev, Mikhail; Cecchi, Lorenzo

    2012-08-01

    Exposure to allergens is pivotal in determining sensitization and allergic symptoms in individuals. Pollen grain counts in ambient air have traditionally been assessed to estimate airborne allergen exposure. However, the exact allergen content of ambient air is unknown. We therefore monitored atmospheric concentrations of birch pollen grains and the matched major birch pollen allergen Bet v 1 simultaneously across Europe within the EU-funded project HIALINE (Health Impacts of Airborne Allergen Information Network).Pollen count was assessed with Hirst type pollen traps at 10 l min-1 at sites in France, United Kingdom, Germany, Italy and Finland. Allergen concentrations in ambient air were sampled at 800 l min-1 with a Chemvol® high-volume cascade impactor equipped with stages PM > 10 μm, 10 μm > PM > 2.5 μm, and in Germany also 2.5 μm > PM > 0.12 μm. The major birch pollen allergen Bet v 1 was determined with an allergen specific ELISA. Bet v 1 isoform patterns were analyzed by 2D-SDS-PAGE blots and mass spectrometric identification. Basophil activation was tested in an FcɛR1-humanized rat basophil cell line passively sensitized with serum of a birch pollen symptomatic patient.Compared to 10 previous years, 2009 was a representative birch pollen season for all stations. About 90% of the allergen was found in the PM > 10 μm fraction at all stations. Bet v 1 isoforms pattern did not vary substantially neither during ripening of pollen nor between different geographical locations. The average European allergen release from birch pollen was 3.2 pg Bet v 1/pollen and did not vary much between the European countries. However, in all countries a >10-fold difference in daily allergen release per pollen was measured which could be explained by long-range transport of pollen with a deviating allergen release. Basophil activation by ambient air extracts correlated better with airborne allergen than with pollen concentration.Although Bet v 1 is a mixture of different

  10. Glutathione-S-transferase: a minor allergen in birch pollen due to limited release from hydrated pollen.

    Directory of Open Access Journals (Sweden)

    Stephan Deifl

    Full Text Available Recently, a protein homologous to glutathione-S-transferases (GST was detected in prominent amounts in birch pollen by proteomic profiling. As members of the GST family are relevant allergens in mites, cockroach and fungi we investigated the allergenic relevance of GST from birch (bGST.bGST was expressed in Escherichia coli, purified and characterized by mass spectrometry. Sera from 217 birch pollen-allergic patients were tested for IgE-reactivity to bGST by ELISA. The mediator-releasing activity of bGST was analysed with IgE-loaded rat basophil leukaemia cells (RBL expressing human FcεRI. BALB/c mice were immunized with bGST or Bet v 1. Antibody and T cell responses to either protein were assessed. IgE-cross-reactivity between bGST with GST from house dust mite, Der p 8, was studied with murine and human sera in ELISA. The release kinetics of bGST and Bet v 1 from birch pollen were assessed in water, simulated lung fluid, 0.9% NaCl and PBS. Eluted proteins were quantified by ELISA and analysed by immunoblotting.Only 13% of 217 birch pollen-allergic patients showed IgE-reactivity to bGST. In RBL assays bGST induced mediator release. Immunization of mice with bGST induced specific IgE and a Th2-dominated cellular immune response comparably to immunization with Bet v 1. bGST did not cross-react with Der p 8. In contrast to Bet v 1, only low amounts of bGST were released from pollen grains upon incubation in water and the different physiological solutions.Although bGST is abundant in birch pollen, immunogenic in mice and able to induce mediator release from effector cells passively loaded with specific IgE, it is a minor allergen for birch pollen-allergic patients. We refer this discrepancy to its limited release from hydrated pollen. Hence, bGST is an example demonstrating that allergenicity depends mainly on rapid elution from airborne particles.

  11. Biochemical modification of wood components

    OpenAIRE

    Josefsson, Peter

    2006-01-01

    The degradation of cellulose found in wood is one of the most important degradation processes for the carbon flux on earth. The degradation is performed by microorganisms that typically use enzymes. Since the cellulose in wood is crystalline and embedded in other polymers, making it inaccessible and durable, the enzymatic methods of cellulose degradation is also complex. In this thesis, the action of some of these enzymes, called cellulases, have been studied both fundamentally and for indust...

  12. Extending temperature sum models to simulate onset of birch flowering on the regional scale

    Science.gov (United States)

    Klein, Christian; Biernath, Christian; Priesack, Eckart

    2015-04-01

    For human health issues a reliable forecast of the onset of flowering of different plants which produce allergenic pollen is important. Yet, there are numerous phenological models available with different degrees of model complexity. All models consider the effect of the air temperatures on plant development; but only few models also include other environmental factors and/or plant internal water and nutrient status. However, the more complex models often use empirical relations without physiological meaning and are often tested against small datasets derived from a limited amount of sites. Most models which are used to simulate plant phenology are based on the temporal integration of temperatures above a defined base temperature. A critical temperature sum then defines the onset of a new phenological stage. The use of models that base on temperatures only, is efficient as temperatures are the most frequently documented and available weather component on global, regional and local scales. These models score by their robustness over a wide range of environmental conditions. However, the simulations sometimes fail by more than 20 days compared to measurements, and thus are not adequate for their use in pollen forecast. We tested the ability of temperature sum models to simulate onset of flowering of wild (e.g. birch) and domestic plants in Bavaria. In a first step we therefore determined both, a regional averaged optimum base temperature and temperature sum for the examined plant species in Bavaria. In the second step, the base temperatures were optimized to each site for the simulation period 2001-2010. Our hypothesis is that domestic plants depend much less on the regional weather conditions than wild plants do, due to low and high genetic variability, respectively. If so, the observed base temperatures of wild plants are smaller for low annual average temperatures and higher for high annual average temperatures. In the cases of domestic plants the optimized base

  13. Tribology in secondary wood machining

    Energy Technology Data Exchange (ETDEWEB)

    Ko, P.L.; Hawthorne, H.M.; Andiappan, J.

    1998-07-01

    Secondary wood manufacturing covers a wide range of products from furniture, cabinets, doors and windows, to musical instruments. Many of these are now mass produced in sophisticated, high speed numerical controlled machines. The performance and the reliability of the tools are key to an efficient and economical manufacturing process as well as to the quality of the finished products. A program concerned with three aspects of tribology of wood machining, namely, tool wear, tool-wood friction characteristics and wood surface quality characterization, was set up in the Integrated Manufacturing Technologies Institute (IMTI) of the National Research Council of Canada. The studies include friction and wear mechanism identification and modeling, wear performance of surface-engineered tool materials, friction-induced vibration and cutting efficiency, and the influence of wear and friction on finished products. This research program underlines the importance of tribology in secondary wood manufacturing and at the same time adds new challenges to tribology research since wood is a complex, heterogeneous, material and its behavior during machining is highly sensitive to the surrounding environments and to the moisture content in the work piece.

  14. From a Traditional Medicinal Plant to a Rational Drug: Understanding the Clinically Proven Wound Healing Efficacy of Birch Bark Extract

    Science.gov (United States)

    Ebeling, Sandra; Naumann, Katrin; Pollok, Simone; Wardecki, Tina; Vidal-y-Sy, Sabine; Nascimento, Juliana M.; Boerries, Melanie; Schmidt, Gudula; Brandner, Johanna M.; Merfort, Irmgard

    2014-01-01

    Background Birch bark has a long lasting history as a traditional medicinal remedy to accelerate wound healing. Recently, the efficacy of birch bark preparations has also been proven clinically. As active principle pentacyclic triterpenes are generally accepted. Here, we report a comprehensive study on the underlying molecular mechanisms of the wound healing properties of a well-defined birch bark preparation named as TE (triterpene extract) as well as the isolated single triterpenes in human primary keratinocytes and porcine ex-vivo wound healing models. Methodology/Principal Findings We show positive wound healing effects of TE and betulin in scratch assay experiments with primary human keratinocytes and in a porcine ex-vivo wound healing model (WHM). Mechanistical studies elucidate that TE and betulin transiently upregulate pro-inflammatory cytokines, chemokines and cyclooxygenase-2 on gene and protein level. For COX-2 and IL-6 this increase of mRNA is due to an mRNA stabilizing effect of TE and betulin, a process in which p38 MAPK and HuR are involved. TE promotes keratinocyte migration, putatively by increasing the formation of actin filopodia, lamellipodia and stress fibers. Detailed analyses show that the TE components betulin, lupeol and erythrodiol exert this effect even in nanomolar concentrations. Targeting the actin cytoskeleton is dependent on the activation of Rho GTPases. Conclusion/Significance Our results provide insights to understand the molecular mechanism of the clinically proven wound healing effect of birch bark. TE and betulin address the inflammatory phase of wound healing by transient up-regulation of several pro-inflammatory mediators. Further, they enhance migration of keratinocytes, which is essential in the second phase of wound healing. Our results, together with the clinically proven efficacy, identify birch bark as the first medical plant with a high potential to improve wound healing, a field which urgently needs effective remedies

  15. Analysis of three types of triterpenoids in tetraploid white birches (Betula platyphylla Suk.) and selection of plus trees

    Institute of Scientific and Technical Information of China (English)

    Sui Wang; Hui Zhao; Jing Jiang; Guifeng Liu; Chuanping Yang

    2015-01-01

    Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction (UAE) to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro-matography (HPLC), three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra-ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel-lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ?C and an extraction time of 15 min. A reversed-phase C18 col-umn (4.6 mm 9 250 mm 9 5 lm) with a column tem-perature of 30 ?C and the mobile phase composed of A (acetonitrile) and B (0.1% aqueous phosphoric acid, v/v) at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference was observed between diploid and tetraploid white birch in terms of the content of three types of triterpenoids (at a confidence level of 0.05). As triterpenoid content, height, and DBH (diameter at breast height) are strongly interre-lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com-prehensive characters.

  16. Soil Chemical and Microbial Properties in a Mixed Stand of Spruce and Birch in the Ore Mountains (Germany—A Case Study

    Directory of Open Access Journals (Sweden)

    Karoline Schua

    2015-06-01

    Full Text Available A major argument for incorporating deciduous tree species in coniferous forest stands is their role in the amelioration and stabilisation of biogeochemical cycles. Current forest management strategies in central Europe aim to increase the area of mixed stands. In order to formulate statements about the ecological effects of mixtures, studies at the stand level are necessary. In a mixed stand of Norway spruce (Picea abies (L. Karst. and silver birch (Betula pendula Roth in the Ore Mountains (Saxony, Germany, the effects of these two tree species on chemical and microbial parameters in the topsoil were studied at one site in the form of a case study. Samples were taken from the O layer and A horizon in areas of the stand influenced by either birch, spruce or a mixture of birch and spruce. The microbial biomass, basal respiration, metabolic quotient, pH-value and the C and N contents and stocks were analysed in the horizons Of, Oh and A. Significantly higher contents of microbial N were observed in the Of and Oh horizons in the birch and in the spruce-birch strata than in the stratum containing only spruce. The same was found with respect to pH-values in the Of horizon and basal respiration in the Oh horizon. Compared to the spruce stratum, in the birch and spruce-birch strata, significantly lower values were found for the contents of organic C and total N in the A horizon. The findings of the case study indicated that single birch trees have significant effects on the chemical and microbial topsoil properties in spruce-dominated stands. Therefore, the admixture of birch in spruce stands may distinctly affect nutrient cycling and may also be relevant for soil carbon sequestration. Further studies of these functional aspects are recommended.

  17. Determination of nitration degrees for the birch pollen allergen Bet v 1.

    Science.gov (United States)

    Selzle, Kathrin; Ackaert, Chloé; Kampf, Christopher J; Kunert, Anna T; Duschl, Albert; Oostingh, Gertie J; Pöschl, Ulrich

    2013-11-01

    Nitration of tyrosine residues in the major birch pollen allergen Bet v 1 may alter the allergenic potential of the protein. The kinetics and mechanism of the nitration reaction, however, have not yet been well characterized. To facilitate further investigations, an efficient method to quantify the nitration degree (ND) of small samples of Bet v 1 is required. Here, we present a suitable method of high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) that can be photometrically calibrated using the amino acids tyrosine (Tyr) and nitrotyrosine (NTyr) without the need for nitrated protein standards. The new method is efficient and in agreement with alternative methods based on hydrolysis and amino acid analysis of tetranitromethane (TNM)-nitrated Bet v 1 standards as well as samples from nitration experiments with peroxynitrite. The results confirm the applicability of the new method for the investigation of the reaction kinetics and mechanism of protein nitration.

  18. Numerical simulation of birch pollen dispersion with an operational weather forecast system.

    Science.gov (United States)

    Vogel, Heike; Pauling, Andreas; Vogel, Bernhard

    2008-11-01

    We included a parameterisation of the emissions of pollen grains into the comprehensive model system COSMO-ART. In addition, a detailed density distribution of birch trees within Switzerland was derived. Based on these new developments, we carried out numerical simulations of the dispersion of pollen grains for an episode that occurred in April 2006 over Switzerland and the adjacent regions. Since COSMO-ART is based on the operational forecast model of the German Weather Service, we are presenting a feasibility study of daily pollen forecast based on methods which have been developed during the last two decades for the treatment of anthropogenic aerosol. A comparison of the model results and very detailed pollen counts documents the current possibilities and the shortcomings of the method and gives hints for necessary improvements.

  19. Intrinsically microporous polyesters from betulin - toward renewable materials for gas separation made from birch bark.

    Science.gov (United States)

    Jeromenok, Jekaterina; Böhlmann, Winfried; Antonietti, Markus; Weber, Jens

    2011-11-15

    Betulin, an abundant triterpene, can be extracted from birch bark and can be used as a renewable monomer in the synthesis of microporous polyesters. Cross-linked networks and hyperbranched polymers are accessible by an A(2) + B(3) reaction, with betulin being the A(2) monomer and B(3) being a trifunctional acid chloride. Reaction of betulin with a diacid dichloride results in linear, soluble polyesters. The present communication proves that the polyreaction follows the classic schemes of polycondensation reactions. The resulting polymers are analyzed with regard to their micro-porosity by gas sorption, NMR spectroscopy, and X-ray scattering methods. The polymers feature intrinsic microporosity, having ultrasmall pores, which makes them candidates for gas separation membranes, e.g., for the separation of CO(2) from N(2) .

  20. Nickel and Copper Toxicity and Plant Response Mechanisms in White Birch (Betula papyrifera).

    Science.gov (United States)

    Theriault, Gabriel; Nkongolo, Kabwe

    2016-08-01

    Nickel (Ni) and copper (Cu) are the most prevalent metals found in the soils in the Greater Sudbury Region (Canada) because of smelting emissions. The main objectives of the present study were to (1) determine the toxicity of nickel (Ni) and copper (Cu) at different doses in Betula papyrifera (white birch), (2) Characterize nickel resistance mechanism, and (3) assess segregating patterns for Ni and Cu resistance in B. papyrifera populations. This study revealed that B. papyrifera is resistant to Ni and Cu concentrations equivalent to the levels reported in metal-contaminated stands in the GSR. Resistant genotypes (RG) accumulate Ni in roots but not in leaves. Moderately susceptible (MSG) and susceptible genotypes (SG) show a high level of Ni translocation to leaves. Gene expression analysis showed differential regulation of genes in RG compared to MSG and SG. Analysis of segregation patterns suggests that resistance to Ni and Cu is controlled by single recessive genes.

  1. 桦木板材的快速干燥%Rapid Drying of Birch Lumber

    Institute of Scientific and Technical Information of China (English)

    李增超; 邱增处; 杨庆; 雷亚芳

    2001-01-01

    采用阶段连续升温干燥基准,增加热湿处理工艺,用炉气间接加热木材干燥窑对不同厚度桦木锯材进行快速窑干工艺试验,实践证明不但干燥周期缩短30%,且提高了干燥质量,易于操作。%Rapid kiln-drying experiment on birch lumber of kiln in whichphased continuous heating drying schedule and the conditioning technology are adopted.It has been proved in practice that such kiln-drying technology can not only shorten the drying period by 30% but also improve drying quality as well as be operated easily.

  2. Breeding increases the efficacy of Chondrostereum purpureum in the sprout control of birch.

    Directory of Open Access Journals (Sweden)

    Leena Hamberg

    Full Text Available We tested whether the pairing of selected isolates could be used to increase the efficiency of a decay fungus Chondrostereum purpureum (Pers. Ex Fr. Pouzar to control hardwood sprouting in Finland. We paired C. purpureum strains efficient in sprout control or highly active in laccase production, and tested the efficacy of their progeny in spout control experiments. This procedure resulted in a strain with an efficacy superior to that of the parental strains. The mortality of birch (Betula pendula Roth. and B. pubescens Ehrh. 1 cm in stump diameter was 78%, 56% and 9% for the best progeny, the best parental strain and the control, respectively. Mortality was only slightly higher for B. pendula than for B. pubescens but no significant differences were found between the number or maximum height of stump sprouts. Our results showed that cross breeding of this decay fungus is a good alternative in attempts to produce efficient biocontrol agents against hardwood sprouting.

  3. Regularizations of the Euler product representation for zeta functions and the Birch--Swinnerton-Dyer conjecture

    CERN Document Server

    Fujimoto, Minoru

    2007-01-01

    We consider a variant expression to regularize the Euler product representation of the zeta functions, where we mainly apply to that of the Riemann zeta function in this paper. The regularization itself is identical to that of the zeta function of the summation expression, but the non-use of the M\\"oebius function enable us to confirm a finite behavior of residual terms which means an absence of zeros except for the critical line. Same technique can be applied to the $L$-function associated to the elliptic curve, and we can deal with the Taylor expansion at the pole in critical strip which is deeply related to the Birch--Swinnerton-Dyer conjecture.

  4. Ligand binding modulates the structural dynamics and compactness of the major birch pollen allergen.

    Science.gov (United States)

    Grutsch, Sarina; Fuchs, Julian E; Freier, Regina; Kofler, Stefan; Bibi, Marium; Asam, Claudia; Wallner, Michael; Ferreira, Fátima; Brandstetter, Hans; Liedl, Klaus R; Tollinger, Martin

    2014-12-16

    Pathogenesis-related plant proteins of class-10 (PR-10) are essential for storage and transport of small molecules. A prominent member of the PR-10 family, the major birch pollen allergen Bet v 1, is the main cause of spring pollinosis in the temperate climate zone of the northern hemisphere. Bet v 1 binds various ligand molecules to its internal cavity, and immunologic effects of the presence of ligand have been discussed. However, the mechanism of binding has remained elusive. In this study, we show that in solution Bet v 1.0101 is conformationally heterogeneous and cannot be represented by a single structure. NMR relaxation data suggest that structural dynamics are fundamental for ligand access to the protein interior. Complex formation then leads to significant rigidification of the protein along with a compaction of its 3D structure. The data presented herein provide a structural basis for understanding the immunogenic and allergenic potential of ligand binding to Bet v 1 allergens.

  5. Effect of Wood Variables on the Properties of Wood Fiber-Polypropylene Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effect of wood species (Chinese fir and Poplar), wood fiber content (10%, 25%, 40%) and wood fiber sizes (16 to 32 mesh, 32-65 mesh, above 65 mesh) on the properties of the wood fiber-Polypropylene composites were studied in this paper. The results indicate that the effect of wood fiber content and size in composite were more important than that of chosen wood species. Compared with polypropylene without wood fiber, the flexural strength of the composites increased when adding wood fiber into polypr...

  6. 超声波辅助提取玉米芯中木聚糖条件优化研究%Ultrasound- Assisted Extraction of Xylan from Corncob

    Institute of Scientific and Technical Information of China (English)

    汪怀建; 谭文津; 丁雪杉; 周跃龙

    2009-01-01

    Ultrasonic technique was employed to extract xylan from corncob. The optimal conditions for the ultrasonic extraction of xylan were determined by response surface methodology. Box Behnken design was applied to evaluate the ef-fects of four independent variables (ultrasonic power, time, temperature and solvent to solid ratio) on the yield of xylan.Results: The obtained optimal conditions for high yield xylan are ultrasonic power 266 w, extraction time 52 min, extrac-tion temperature 71.1 ℃, and solvent to solid ratio 20.39. Under the optimal conditions, the yield of xylan from comcob is 29.772 2%. Compared to traditional extraction technique, the ultrasound - assisted extraction technique increases the yield of xylan from corncob by 17. 382%. In addition, using the ultrasound technique, extraction time is significantly shortened and extraction temperature is decreased.%利用超声波辅助法提取玉米芯木聚糖,通过响应面分析得出超声波辅助法提取玉米芯木聚糖的最佳条件为:以10%NaOH溶液为提取溶剂,超声波功率为266 w,提取时间为52 min,提取温度为71.1℃,液料比为20.39(mL/g).在此条件下,通过试验验证得出,玉米芯木聚糖提取率平均值为29.772 2%,与预测值非常相近.与传统提取方法相比,超声波辅助法显著提高了玉米芯木聚糖提取率,提高了17.382%,而且超声波辅助提取法大大缩短了提取时间,降低了提取温度.

  7. 甜玉米穗轴提取水溶性木聚糖的研究%Extraction of water-soluble xylan from sweet corn cobs

    Institute of Scientific and Technical Information of China (English)

    刘晓飞; 张娜; 荆丽荣; 王伟婷; 马永强

    2012-01-01

    旨在寻找一种甜玉米穗轴中水溶性木聚糖的提取和纯化方法。以甜玉米穗轴为原料,采用酸预处理高温蒸煮法提取木聚糖,正交实验后获得提取方法的最佳条件,并验证其提取率。木聚糖液经脱色、脱蛋白处理后,使用Capto Q阴离子交换树脂对木聚糖液进行纯化。结果如下:3g/L的H2SO4浸泡12h后,料液比为1:10,蒸煮温度为150℃,蒸煮时间为60min,提取率为27.32%。柱层析纯化后,木聚糖提取液的收率为51.8%,冻干粉木聚糖含量为82.7%。本文对甜玉米穗轴的木聚糖提取和纯化工艺进行了可行性研究和数据支持。%The aim was to establish a method of extracting and purifying Water-Soluble xylan from sweet corn cobs.Xylan was extracted from sweet corn cobs through stewing method and the optimized conditions of the extraction method were confirmed by the orthogonal experiment. The extraction efficiency was determined subsequently.Simultaneously xylan from sweet corn cobs was purified by Capto Q after disposing of decoloration and removing protein.The results were shown as follows:sweet corn cobs were soaked by 3g/L H2SO4after 12h, the ratio of solid to liquid 1:10( g: mL),the temperature and time of stewing were 150℃ and 60rain, respectively. Using column chromatography,the dry powder content and yield of xylan were 82.7% and 51.8%, respectively.The optimum extraction ratio of this method was 27.32%.In this study,the water-soluble xylan of sweet corn cobs was extracted and purified,the supporting of experiment data were provided for the future xylan industrialization.

  8. Swelling of acetylated wood in organic liquids

    CERN Document Server

    Obataya, E; Obataya, Eiichi; Gril, Joseph

    2005-01-01

    To investigate the affinity of acetylated wood for organic liquids, Yezo spruce wood specimens were acetylated with acetic anhydride, and their swelling in various liquids were compared to those of untreated specimens. The acetylated wood was rapidly and remarkably swollen in aprotic organic liquids such as benzene and toluene in which the untreated wood was swollen only slightly and/or very slowly. On the other hand, the swelling of wood in water, ethylene glycol and alcohols remained unchanged or decreased by the acetylation. Consequently the maximum volume of wood swollen in organic liquids was always larger than that in water. The effect of acetylation on the maximum swollen volume of wood was greater in liquids having smaller solubility parameters. The easier penetration of aprotic organic liquids into the acetylated wood was considered to be due to the scission of hydrogen bonds among the amorphous wood constituents by the substitution of hydroxyl groups with hydrophobic acetyl groups.

  9. Genome sequence of dwarf birch (Betula nana) and cross-species RAD markers.

    Science.gov (United States)

    Wang, Nian; Thomson, Marian; Bodles, William J A; Crawford, Robert M M; Hunt, Harriet V; Featherstone, Alan Watson; Pellicer, Jaume; Buggs, Richard J A

    2013-06-01

    New sequencing technologies allow development of genome-wide markers for any genus of ecological interest, including plant genera such as Betula (birch) that have previously proved difficult to study due to widespread polyploidy and hybridization. We present a de novo reference genome sequence assembly, from 66× short read coverage, of Betula nana (dwarf birch) - a diploid that is the keystone woody species of subarctic scrub communities but of conservation concern in Britain. We also present 100 bp PstI RAD markers for B. nana and closely related Betula tree species. Assembly of RAD markers in 15 individuals by alignment to the reference B. nana genome yielded 44-86k RAD loci per individual, whereas de novo RAD assembly yielded 64-121k loci per individual. Of the loci assembled by the de novo method, 3k homologous loci were found in all 15 individuals studied, and 35k in 10 or more individuals. Matching of RAD loci to RAD locus catalogues from the B. nana individual used for the reference genome showed similar numbers of matches from both methods of RAD locus assembly but indicated that the de novo RAD assembly method may overassemble some paralogous loci. In 12 individuals hetero-specific to B. nana 37-47k RAD loci matched a catalogue of RAD loci from the B. nana individual used for the reference genome, whereas 44-60k RAD loci aligned to the B. nana reference genome itself. We present a preliminary study of allele sharing among species, demonstrating the utility of the data for introgression studies and for the identification of species-specific alleles.

  10. Effects of carbon dioxide concentration and nutrition on photosynthetic functions of white birch seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. [Lakehead Univ., Thunder Bay, ON (Canada). Faculty of Forestry and the Forest Environment; Dang, Q.L. [Lakehead Univ., Thunder Bay, ON (Canada). Faculty of Forest and the Forest Environment; Chinese Academy of Sciences, Beijing (China). Inst. of Botany, Laboratory of Quantitative Vegetation Ecology

    2006-11-15

    Increases in atmospheric carbon dioxide (CO{sub 2}) can impact photosynthesis and dry mass production of plants. This study investigated the physiological responses of white birch seedlings to elevated carbon dioxide (CO{sub 2}) at low and high supplies of nitrogen (N), phosphorus (P) and potassium (K). A 2-way factorial experiment was carried out with birch seedlings grown for 4 months in environment-controlled greenhouses. Elevated CO{sub 2} enhanced maximal carboxylation rate and photosynthetically active radiation-saturated electron transport rates were measured after 2.5 and 3.5 months of treatment, as well as actual photochemical efficiency and photosynthetic linear electron transport to carboxylation. Net photosynthetic rate increases were observed as well as increases in photosynthetic water use efficiency (WUE); photosynthetic N efficiency and P efficiency. Stomatal conductance, transpiration rate and the fraction of total photosynthetic linear electron transport partitioned to oxygenation were reduced. Low nutrient availability decreased net photosynthetic rates, WUE, and triose phosphate utilization. However, photosynthetic linear electron transport and N use efficiency increased. There were significant interactive effects of CO{sub 2} and nutrition over time, with evidence of photosynthetic up-regulation in response to elevated CO{sub 2} in seedlings receiving high nutrition. Photosynthetic depression in response to low nutrient availability was attributed to biochemical limitation rather than stomatal limitation. Elevated CO{sub 2} reduced leaf N concentration in seedlings receiving low nutrition, but had no significant effect on leaf P or K concentrations. High nutrient availability generally increased area-based leaf N, P and K concentrations but had negligible effects on K after 2.5 months of treatment. Results suggested that increases in electron partitioning to photorespiration in response to low nutrient availability may be related to

  11. Pentacyclic triterpenes in birch bark extract inhibit early step of herpes simplex virus type 1 replication.

    Science.gov (United States)

    Heidary Navid, M; Laszczyk-Lauer, M N; Reichling, J; Schnitzler, P

    2014-09-25

    Antiviral agents frequently applied for treatment of herpesvirus infections include acyclovir and its derivatives. The antiviral effect of a triterpene extract of birch bark and its major pentacyclic triterpenes, i.e. betulin, lupeol and betulinic acid against acyclovir-sensitive and acyclovir-resistant HSV type 1 strains was examined. The cytotoxic effect of a phytochemically defined birch bark triterpene extract (TE) as well as different pentacyclic triterpenes was analyzed in cell culture, and revealed a moderate cytotoxicity on RC-37 cells. TE, betulin, lupeol and betulinic acid exhibited high levels of antiviral activity against HSV-1 in viral suspension tests with IC50 values ranging between 0.2 and 0.5 μg/ml. Infectivity of acyclovir-sensitive and clinical isolates of acyclovir-resistant HSV-1 strains was significantly reduced by all tested compounds and a direct concentration- and time-dependent antiherpetic activity could be demonstrated. In order to determine the mode of antiviral action, TE and the compounds were added at different times during the viral infection cycle. Addition of these drugs to uninfected cells prior to infection or to herpesvirus-infected cells during intracellular replication had low effect on virus multiplication. Minor virucidal activity of triterpenes was observed, however both TE and tested compounds exhibited high anti-herpetic activity when viruses were pretreated with these drugs prior to infection. Pentacyclic triterpenes inhibit acyclovir-sensitive and acyclovir-resistant clinical isolates of HSV-1 in the early phase of infection. Copyright © 2014 Elsevier GmbH. All rights reserved.

  12. PRESENCE OF WATER-SOLUBLE COMPOUNDS IN THERMALLY MODIFIED WOOD: CARBOHYDRATES AND FURFURALS

    Directory of Open Access Journals (Sweden)

    Olov Karlsson,

    2012-06-01

    Full Text Available With thermal modification, changes in properties of wood, such as the presence of VOC and water-soluble carbohydrates, may occur. Thermal modifications under saturated steam conditions (160 °C or 170 °C and superheated steam conditions (170, 185, and 212 °C were investigated by analysing the presence of water-soluble 5-(hydroxymethylfurfural (HMF, furfural, and carbohydrates in heat-treated wood. The influence of thermal modifications on Scots pine, Norway spruce, and silver birch was also studied. Furfurals were analysed using HPLC at 280 nm, while monosaccharides and water-soluble carbohydrates were determined by GC-FID as their acetylated alditiols and, after methanolysis, as their trimethylsilylated methyl-glycosides, respectively. The amount of furfurals was larger in boards thermally modified under saturated steam conditions than those treated under superheated steam conditions. Generally, more of HMF than furfural was found in the thermally modified boards. In process water, in which saturated steam conditions had been used, furfural and only traces of HMF were found. Higher content of water-soluble carbohydrates was found in boards treated in saturated steam rather than in superheated steam. After modification in saturated steam, substantial parts of the water-soluble carbohydrates were due to monosaccharides, but only traces of monosaccharides were found in boards treated under superheated steam conditions.

  13. Interface Characteristics of Wood-hybrid Composites

    Institute of Scientific and Technical Information of China (English)

    XUEFenglian; ZHAOGuangjie

    2005-01-01

    In order to understand the current interface characteristics of wood-hybrid composites, this paper starts off from the concept of composite interface and general theory of interface form, then the inner-surface and microstructure of wood and the interface characteristics of composites, such as wood- inorganic, wood-plastic and wood- metal made by electroless plating technique, are concluded and discussed in detail. Meanwhile,on the basis of that, some points of view about how to develop the wood-hybrid composites interface research in the future are also proposed.

  14. WOOD MODIFICATION BY HEAT TREATMENT: A REVIEW

    Directory of Open Access Journals (Sweden)

    Bruno M. Esteves

    2009-02-01

    Full Text Available Wood heat treatment has increased significantly in the last few years and is still growing as an industrial process to improve some wood properties. The first studies on heat treatment investigated mainly equilibrium mois-ture, dimensional stability, durability and mechanical properties. Mass loss, wettability, wood color, and chemical transformations have been subsequently extensively studied, while recent works focus on quality control, modeling, and study the reasons for the improvements. This review explains the recent interest on the heat treatment of wood and synthesizes the major publications on this subject on wood properties, chemical changes, wood uses, and quality control.

  15. wood burns down

    Directory of Open Access Journals (Sweden)

    Vladimir Bukh

    2004-11-01

    Full Text Available To relax the local authorities and to receive the guests of high rank «with no tie» the so-called «Fisherman's House» was built at the source of Angara-river, near Lake Baikal. Vladimir Ivanov, a young architect, was noticed by his skillful performa nee of exclusive orders and became the author of this house. At the time of ferroconcrete boom the proposal to build a wooden guest house turned out to be unexpectedly to the point and was graciously approved. The economic department was entrusted to select the men good for carpenter's work, and the forestry department was entrusted to provide thick round timber. And the work started. But, as it usually happens, the workers did not take the trouble and made the first eight rims of the current timber with an inappropriate diameter.And when Pavlov insisted on demolishing the construction and replacing the logs by the logs with the necessary diameter, the building work obeyed to his will and was finished suecessfully.The architecture of the house is not the derived action of the saw and the fret-saw. It is a technology of the axe. It is natural, convincing and original. It is no use to look for the local sources in it. It grew up in the area of timber and cold winter. And this clear and efficient action kept the construction from the annoying vulgarity and provided Siberian exotics easily penetrating into one's soul, refined as it may be.One of the eminent guests said with admiration: «Even if Pavlov had created nothing more, he would have justified his professional choice with this single house.» Why not to say it as a good toast. However, this is a suitable case to add: style is an absence of style. It is a taste.After the Fisherman's House Irkutsk architects were attracted by wood. They followed the strictness in wood and, as much as they could, created a couple of successful remakes, until the cylinder logs and ... new

  16. Prevention of birch pollen-related food allergy by mucosal treatment with multi-allergen-chimers in mice.

    Directory of Open Access Journals (Sweden)

    Elisabeth Hoflehner

    Full Text Available BACKGROUND: Among birch pollen allergic patients up to 70% develop allergic reactions to Bet v 1-homologue food allergens such as Api g 1 (celery or Dau c 1 (carrot, termed as birch pollen-related food allergy. In most cases, specific immunotherapy with birch pollen extracts does not reduce allergic symptoms to the homologue food allergens. We therefore genetically engineered a multi-allergen chimer and tested if mucosal treatment with this construct could represent a novel approach for prevention of birch pollen-related food allergy. METHODOLOGY: BALB/c mice were poly-sensitized with a mixture of Bet v 1, Api g 1 and Dau c 1 followed by a sublingual challenge with carrot, celery and birch pollen extracts. For prevention of allergy sensitization an allergen chimer composed of immunodominant T cell epitopes of Api g 1 and Dau c 1 linked to the whole Bet v 1 allergen, was intranasally applied prior to sensitization. RESULTS: Intranasal pretreatment with the allergen chimer led to significantly decreased antigen-specific IgE-dependent β-hexosaminidase release, but enhanced allergen-specific IgG2a and IgA antibodies. Accordingly, IL-4 levels in spleen cell cultures and IL-5 levels in restimulated spleen and cervical lymph node cell cultures were markedly reduced, while IFN-γ levels were increased. Immunomodulation was associated with increased IL-10, TGF-β and Foxp3 mRNA levels in NALT and Foxp3 in oral mucosal tissues. Treatment with anti-TGF-β, anti-IL10R or anti-CD25 antibodies abrogated the suppression of allergic responses induced by the chimer. CONCLUSION: Our results indicate that mucosal application of the allergen chimer led to decreased Th2 immune responses against Bet v 1 and its homologue food allergens Api g 1 and Dau c 1 by regulatory and Th1-biased immune responses. These data suggest that mucosal treatment with a multi-allergen vaccine could be a promising treatment strategy to prevent birch pollen-related food allergy.

  17. Production of furfural from xylose, xylan and corncob in gamma-valerolactone using FeCl3·6H2O as catalyst.

    Science.gov (United States)

    Zhang, Luxin; Yu, Hongbing; Wang, Pan; Li, Yong

    2014-01-01

    An efficient and simple one-pot monophasic reaction system with small carbon footprint for converting xylose, xylan and corncob into furfural was developed in gamma-valerolactone (GVL, an ideal sustainable solvent derived from lignocelluloses) by using FeCl3·6H2O as catalyst. Good yields of furfural from xylose were obtained, and the system was shown to work for xylan and corncob as well. A surprisingly high furfural yield of 79.6% from untreated corncob was achieved at 458 K for 100 min. Contrary to what was generally believed, the addition of water, reduced the rate of the reactions, but showed positive effect on preventing the furfural from degradation in GVL. Besides, the C6 sugars (glucose and cellulose) afforded 11.4-24.5% furfural yields when employing this catalytic approach. The reaction system proposed in this manuscript showed great potential for optimizing the catalytic process in furfural production.

  18. Furfural Production from d-Xylose and Xylan by Using Stable Nafion NR50 and NaCl in a Microwave-Assisted Biphasic Reaction

    Directory of Open Access Journals (Sweden)

    Sarah Le Guenic

    2016-08-01

    Full Text Available Pentose dehydration and direct transformation of xylan into furfural were performed in a water-cyclopentyl methyl ether (CPME biphasic system under microwave irradiation. Heated up between 170 and 190 °C in the presence of Nafion NR50 and NaCl, d-xylose, l-arabinose and xylan gave furfural with maximum yields of 80%, 42% and 55%, respectively. The influence of temperature and reaction time on the reaction kinetics was discussed. This study was also completed by the survey of different reactant ratios, such as organic layer-water or catalyst-inorganic salt ratios. The exchange between proton and cation induced by an excess of NaCl was monitored, and a synergetic effect between the remaining protons and the released HCl was also discovered.

  19. Comparison of throughfall and soil solution chemistry between a high-density Corsican pine stand and a naturally regenerated silver birch stand.

    Science.gov (United States)

    De Schrijver, A; Nachtergale, L; Staelens, J; Luyssaert, S; De Keersmaeker, L

    2004-09-01

    In Flanders, critical loads for acidification and eutrophication are exceeded in the majority of the forest stands, and many previously nitrogen limited forest ecosystems have become nitrogen saturated. The present study investigates whether a naturally regenerated stand of silver birch (Betula pendula Roth) contributes less to the acidification and eutrophication of the forest soil than a high-density plantation of Corsican pine (Pinus nigra ssp. laricio Maire). Throughfall deposition of inorganic nitrogen was about 3.5 times higher in the Corsican pine stand than in the birch stand. Potassium throughfall deposition was significantly higher under birch due to higher canopy leaching. Magnesium throughfall deposition was significantly higher under the pine canopy due to higher dry deposition. The lower nitrogen throughfall deposition in the birch stand was reflected in a 60% lower nitrate percolation at 1m depth compared with pine. Nitrate soil percolation is linked to losses of aluminium and base cations.

  20. Enzymatic Production of Xylan from Rice Hull%酶法制备稻壳木聚糖的研究

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 杨箐; 李达

    2015-01-01

    Starch and protein in rice hull were degraded byα-amylase and alkaline protease respectively , then xylan were produced from rice hull. The optimal experimental conditions for hydrolyzing starch are: the temperature was 100℃,the ratio of stuff and liquid was 1:12 g:mL, digestion time was 20 min,and enzyme concentration was 1.5%wheat bran starch. The remained content of starch is reduced to 0.72% from original 21.52%. The optimal experimental conditions for hydrolyzing protein are:the temperature was 50℃, the ratio of stuff and liquid was 1:12 g:mL, digest time was 120 min, and enzyme concentration was 3%wheat bran protein.The remained content of protein in destarched rice hull is 2.97%. The destarched and deproteined rice hull contents 46.68% xylan.%采用α-淀粉酶和碱性蛋白酶分别降解稻壳中的淀粉和蛋白质,来制备稻壳木聚糖.在淀粉的酶解中,通过实验分析得出最佳酶解条件为:料液比1:12 g/mL,水解温度100℃,加酶量1.5%稻壳淀粉,反应时间20 min.稻壳中淀粉的含量从21.52%降至0.72%.在蛋白质的酶解中,通过实验分析得出最佳酶解条件为:料液比1:12 g/mL,反应温度50℃,加酶量3%稻壳蛋白,酶解时间120 min.酶解后稻壳中蛋白质残留量为2.97%.经过去淀粉和蛋白质的稻壳中木聚糖含量为46.68%.

  1. Asparagus IRX9, IRX10, and IRX14A Are Components of an Active Xylan Backbone Synthase Complex that Forms in the Golgi Apparatus.

    Science.gov (United States)

    Zeng, Wei; Lampugnani, Edwin R; Picard, Kelsey L; Song, Lili; Wu, Ai-Min; Farion, Isabela M; Zhao, Jia; Ford, Kris; Doblin, Monika S; Bacic, Antony

    2016-05-01

    Heteroxylans are abundant components of plant cell walls and provide important raw materials for the food, pharmaceutical, and biofuel industries. A number of studies in Arabidopsis (Arabidopsis thaliana) have suggested that the IRREGULAR XYLEM9 (IRX9), IRX10, and IRX14 proteins, as well as their homologs, are involved in xylan synthesis via a Golgi-localized complex termed the xylan synthase complex (XSC). However, both the biochemical and cell biological research lags the genetic and molecular evidence. In this study, we characterized garden asparagus (Asparagus officinalis) stem xylan biosynthesis genes (AoIRX9, AoIRX9L, AoIRX10, AoIRX14A, and AoIRX14B) by heterologous expression in Nicotiana benthamiana We reconstituted and partially purified an active XSC and showed that three proteins, AoIRX9, AoIRX10, and AoIRX14A, are necessary for xylan xylosyltranferase activity in planta. To better understand the XSC structure and its composition, we carried out coimmunoprecipitation and bimolecular fluorescence complementation analysis to show the molecular interactions between these three IRX proteins. Using a site-directed mutagenesis approach, we showed that the DxD motifs of AoIRX10 and AoIRX14A are crucial for the catalytic activity. These data provide, to our knowledge, the first lines of biochemical and cell biological evidence that AoIRX9, AoIRX10, and AoIRX14A are core components of a Golgi-localized XSC, each with distinct roles for effective heteroxylan biosynthesis.

  2. Xylan-regulated delivery of human keratinocyte growth factor-2 to the inflamed colon by the human anaerobic commensal bacterium Bacteroides ovatus.

    Science.gov (United States)

    Hamady, Zaed Z R; Scott, Nigel; Farrar, Mark D; Lodge, J Peter A; Holland, Keith T; Whitehead, Terence; Carding, Simon R

    2010-04-01

    Human growth factors are potential therapeutic agents for various inflammatory disorders affecting the gastrointestinal tract. However, they are unstable when administered orally and systemic administration requires high doses increasing the risk of unwanted side effects. Live microorganism-based delivery systems can overcome these problems although they suffer from the inability to control heterologous protein production and there are concerns regarding biosafety and environmental contamination. To overcome these limitations we have developed a new live bacteria drug-delivery system using the human commensal gut bacterium Bacteroides ovatus engineered to secrete human growth factors in response to dietary xylan. The anaerobic nature of B ovatus provides an inherent biosafety feature. B ovatus strains expressing human keratinocyte growth factor-2, which plays a central role in intestinal epithelial homeostasis and repair (BO-KGF), were generated by homologous recombination and evaluated using the dextran sodium sulfate (DSS)-induced model of intestinal epithelial injury and colitis. In response to xylan BO-KGF produced biologically active KGF both in vitro and in vivo. In DSS treated mice administration of xylan and BO-KGF had a significant therapeutic effect in reducing weight loss, improving stool consistency, reducing rectal bleeding, accelerating healing of damaged epithelium, reducing inflammation and neutrophil infiltration, reducing expression of pro-inflammatory cytokines, and accelerating production of goblet cells. BO-KGF and xylan treatment also had a marked prophylactic effect limiting the development of inflammation and disruption of the epithelial barrier. This novel, diet-regulated, live bacterial drug delivery system may be applicable to treating various bowel disorders.

  3. Study on Ultrasonic Extraction of Xylan from Corncob%基于超声波的玉米芯木聚糖提取方法研究

    Institute of Scientific and Technical Information of China (English)

    贾光锋; 陆文总; 赵晨; 樊锐; 苏加强

    2014-01-01

    木聚糖是一种低热量的生物活性物质,广泛应用于食品和医药工业。为了充分地利用农业废弃物(玉米芯),采用超声波法提取玉米芯中的木聚糖,讨论了液固比、碱液浓度、超声功率、超声时间和温度对木聚糖提取率的影响。结果表明:在液固比20∶1 mL/g,NaOH溶液浓度10%,超声功率240 W,超声时间40 min和提取温度65℃条件下,可以获得高质量和高提取率的木聚糖。利用超声波法从玉米芯中提取木聚糖成本低、能耗小和效率高,具有重要的应用价值。%As a low calorie bioactive compound, xylan was widely used in food and pharmaceutical industry. In order to take full advantage of agricultural waste, ultrasound was utilized to extract xylan from corncob. Five factors were discussed including to liquid-solid ratio, base solution concentration, ultrasound power, ultrasound time and temperature. It was shown that xylan with high quality and extraction rate was prepared under following conditions:liquid-solid ratio 20∶1 mL/g, NaOH concentration 10%, ultrasound power 240 W, ultrasound time 40min and temperature 65 ℃. Ultrasound technology used to extract xylan from corncob could lower cost, decrease energy consumption and improve extraction efficiency, which has important practical application value.

  4. Optimization for Ultrasonic-assisted Extraction of Xylan from Bagasse%超声波辅助提取甘蔗渣木聚糖工艺优化

    Institute of Scientific and Technical Information of China (English)

    孙健; 李丽; 盛金凤; 何雪梅; 李昌宝; 赵谋明; 游向荣; 刘国明

    2013-01-01

      This research was to extract and produce xylan from bagasse , which provided a theoretical and methodological instruction for development and utilization of sugarcane by-products. On the basis of single factor test, the response surface method was designed to study the effects of NaOH concentration, liquid material rate and ultrasonic processing time on xylan extraction rate. The results showed that the optimum condition for ultrasonic-assisted extraction of xylan was as follows:NaOH concentration 6%, liquid material rate 38∶1(mL/g), and ultrasonic processing time 28.4 min. Under this condition, the actual average extraction rate of xylan was 28.39%.%  以甘蔗渣为原料制备木聚糖,为甘蔗加工副产物的深度开发及工业化利用提供理论和方法参考。采用超声波辅助提取甘蔗渣中木聚糖,在单因素试验的基础上,采用响应曲面法研究了NaOH浓度、液料比、超声波处理时间对木聚糖提取效果的影响。结果表明,超声波辅助提取甘蔗渣中木聚糖的最佳条件为 NaOH浓度6%、液料比38∶1(mL/g),超声波处理时间28.4 min。在此条件下实际测得的平均提取率为28.39%。

  5. Pyrolysis Kinetics of Physical Components of Wood and Wood-Polymers Using Isoconversion Method

    Directory of Open Access Journals (Sweden)

    John Zondlo

    2013-01-01

    Full Text Available Two hardwood species, namely red oak and yellow-poplar, were separated into their bark, sapwood and heartwood components. The samples were tested for calorific value, specific gravity, proximate analysis, mineral composition, chemical composition, ultimate analysis, and thermo-chemical decomposition behavior. In addition, the thermo-chemical decomposition behaviors of cellulose, xylan, and lignin polymers were also tested. Thermo-chemical decomposition behavior was assessed using a thermo-gravimetric (TGA system by heating the sample from 50 °C to 700 °C at the heating rates of 10, 30 and 50 °C/min under nitrogen. The activation energy was calculated for various fractional conversion values using the isoconversion method. The results showed that char yields of lignin, cellulose and xylan were 41.43%, 4.45% and 1.89%, respectively, at the end of pyrolysis. Furthermore, cellulose, xylan and lignin decomposed dramatically in the temperature range of 320 °C to 360 °C, 150 °C to 230 °C and 100 °C to 410 °C, respectively, with decomposition peaks occurring at 340 °C, 200 °C and 340 °C, respectively. In addition, the maximum activation energy for cellulose was 381 kJ/mol at 360 °C and for xylan it was 348 kJ/mol at 210 °C.

  6. 木醋液体外抗氧化活性评价%Evaluation of Antioxidant Activities of Wood Vinegar in vitro

    Institute of Scientific and Technical Information of China (English)

    段晓玲; 王海英; 刘志明; 冯晨; 余森海

    2015-01-01

    对比了白桦、杂木、木屑以及蒸馏木屑4种木醋液的还原能力,二苯基苦基肼自由基( DPPH·)的清除能力和羟基自由基(·OH)的清除能力。结果表明,4种木醋液有较强的还原能力,其中还原能力最强的是木屑木醋液,半数有效浓度(EC50)为(1.73±0.06)g/L;4种木醋液可有效清除 DPPH·,木屑木醋液清除效果最佳,半数抑制浓度(IC50)为(0.20±0.01)g/L;4种木醋液的·OH清除能力相对较弱,除木屑木醋液IC50为(9.69±0.20)g/L外,其他3种木醋液清除率均未达到50%。%The reducing power and the scavenging activities against phenyl picryl hydrazine radical ( DPPH·) and hydroxyl radical (·OH ) of birch wood vinegar ( BWV ) , miscellaneous wood vinegar ( MWV ) , sawdust wood vinegar ( SWV ) , and distillated sawdust wood vinegar( DWV) were determined. The results showed that four kinds of wood vinegar had strong reducing power and the reducing power of sawdust wood vinegar was the strongest with the half effective concentration (EC50) of (1. 73 ± 0. 06) g/L. Wood vinegar could effectively scavenge DPPH·, and DPPH· scavenging activity of sawdust wood vinegar was the highest with the median inhibitory concentration (IC50) of (0. 20 ± 0. 01) g/L. Wood vinegar showed relatively weak·OH scavenging ability, except the IC50 of sawdust wood vinegar was (9. 69 ± 0. 20) g/L, the·OH scavenging rates of the other three kinds of wood vinegar couldn′t reach 50%.

  7. Characterization of the xylanases from the new isolated thermophilic xylan-degrading Bacillus thermoleovorans strain K-3d and Bacillus flavothermus strain LB3A.

    Science.gov (United States)

    Sunna, A; Prowe, S G; Stoffregen, T; Antranikian, G

    1997-03-15

    Three strictly aerobic strains (K-1, K-3d and K-4) were isolated from a hot-spring in Kobe, Japan, and a facultative anaerobic strain LB3A was isolated from sediments collected from the alkaline Lake Bogoria, Kenya. All strains were thermophilic and capable of growth on xylan. On the basis of morphological, physiological and phylogenetic studies the new aerobic isolates resemble the thermophilic species Bacillus thermoleovorans while the facultative anaerobic isolate LB3A resembles the facultative anaerobic thermophilic species Bacillus flavothermus. When grown on xylan as sole carbon source, all isolates produce thermoactive xylanases, Xylanases from strains K-3d and LB3A are active at temperatures between 40 and 90 degrees C and pH values between 5.0 and 9.0. Applying SDS-PAGE the crude xylanase complex of isolate K-3d was shown to be composed of two active bands, with molecular masses of 40 and 69 kDa. The crude xylanase complex of isolate LB3A, on the other hand, is composed of at least four activity bands with molecular masses ranging from 80 to 130 kDa. Due to the product pattern of xylan hydrolysis both enzymes are classified as endoxylanases. The xylanolytic enzyme system of isolate K-3d produces xylotriose, xylotetraose and larger xylooligosacharides, whereas the xylanases from isolate LB3A release xylotetraose as the major product of hydrolysis.

  8. Producing xylan/Eudragit® S100-based microparticles by chemical and physico-mechanical approaches as carriers for 5-aminosalicylic acid.

    Science.gov (United States)

    Silva, Acarilia Eduardo; Oliveira, Elquio Eleamen; Gomes, Monique C Salgado; Marcelino, Henrique Rodrigues; Silva, Karen C Holanda; Souza, Bartolomeu Santos; Nagashima, Toshiyuki; Ayala, Alejandro Pedro; Oliveira, Anselmo Gomes; do Egito, Eryvaldo Sócrates Tabosa

    2013-01-01

    Xylan is a biopolymer found in a variety of cell wall plants. Eudragit® S-100 (ES100), a pH-dependent polymer, is used as a coating material in gastroresistant delivery systems. In this study, microparticles based on both polymers were produced by interfacial cross-linking polymerisation and/or spray-drying technique in order to investigate feasibility and stability of the systems. Size and morphology of the microparticles were characterised by optical and SEM while FT-IR, thermal analysis (TG/DTA), and X-ray diffraction (XRD) evaluated the drug-polymer interactions and the thermal behaviour of the systems. FT-IR confirmed the absence of chemical interaction between the polymers. TG/DTA analysis showed a higher stability for spray-dried microparticles and XRD data proved the amorphous feature of both carriers. The results reveal that xylan/ES100 microparticles can be produced by chemical or physico-mechanical ways, the latter being the best option due to the lack of toxic cross-linking agents and easy scale-up.

  9. Synthesis of Acylated Xylan-Based Magnetic Fe3O4 Hydrogels and Their Application for H2O2 Detection

    Directory of Open Access Journals (Sweden)

    Qing-Qing Dai

    2016-08-01

    Full Text Available Acylated xylan-based magnetic Fe3O4 nanocomposite hydrogels (ACX-MNP-gels were prepared by fabricating Fe3O4 nanoctahedra in situ within a hydrogel matrix which was synthesized by the copolymerization of acylated xylan (ACX with acrylamide and N-isopropylacrylamide under ultraviolet irradiation. The size of the Fe3O4 fabricated within the hydrogel matrix could be adjusted through controlling the crosslinking concentrations (C. The magnetic hydrogels showed desirable magnetic and mechanical properties, which were confirmed by XRD, Raman spectroscopy, physical property measurement system, SEM, TGA, and compression test. Moreover, the catalytic performance of the magnetic hydrogels was explored. The magnetic hydrogels (C = 7.5 wt % presented excellent catalytic activity and provided a sensitive response to H2O2 detection even at a concentration level of 5 × 10−6 mol·L−1. This approach to preparing magnetic hydrogels loaded with Fe3O4 nanoparticles endows xylan-based hydrogels with new promising applications in biotechnology and environmental chemistry.

  10. Construction of Escherichia Coli by Xylan for Growth%利用木聚糖生长的大肠杆菌的构建

    Institute of Scientific and Technical Information of China (English)

    王翠薇; 李哲; 屈虹男; 李春

    2014-01-01

    Xylan,a renewable resource,has a lower cost and is prepared with simpler method as glucose,lactose,fructose,glycerin and other usual carbon resources in the microbial fermentation.The research reported on the pathway using xylan directly and was transformed into Escherichia coli and the engineered strain BL21-xyn-xyl was succeeded in constructing.The strain could degrade xylan into xylose which was used to metabolic growth and its late growth was superior to the control strain BL21 (DE3).%木聚糖是一种可再生资源,与葡萄糖、乳糖、果糖、甘油等微生物发酵中常用碳源相比,具有价格低廉和制取方法简便的优势。本研究利用合成生物学的方法,将直接利用木聚糖的途径以质粒的形式导入到大肠杆菌体内,成功构建了工程菌株BL21-xyn-xyl。此菌株可以将木聚糖降解为木糖,用于自身代谢生长,其后期生长状况明显优于原始菌株BL21(DE3)。

  11. Review on Wood Discoloration and its Control

    Institute of Scientific and Technical Information of China (English)

    JIANG Zehui; LV Wenhua; FEI Benhua; REN Haiqing; WU Yuzhang

    2006-01-01

    This paper reviews the mechanisms,types, compositions, affecting factors,prevention and remediable treatments of wood discoloration, and especially puts forward the biological control against wood stain and wood induced coloration.The authors think the followings are important:1)Developing the low poisonous or non-toxic, high-efficient and multi-functional anti-stain chemicals is still an important research direction to control wood discoloration.2)It is still very necessary to remove wood stain and restore wood original color and commercial value.3)The biological control has little environmental pollution and its cost is low.Researches on its theories and application should be strengthened.4)Wood color can be induced and turned to be the needed through heat treatment or ultraviolet irradiation without coloring materials,i.e.induced coloration,is a good idea to modulate wood,bamboo or rattan cane color.Itis becoming a new study field.

  12. Wood duck studies : Des Lacs NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This memorandum summarizes wood duck studies on Des Lacs National Wildlife Refuge and provides a brief history on the status of wood ducks on the edge of their...

  13. SYNERGISTIC WOOD PRESERVATIVES FOR REPLACEMENT OF CCA

    Science.gov (United States)

    The objective of this project was to evaluate the potential synergistic combinations of environmentally-safe biocides as wood preservatives. These wood preservatives could be potential replacements for the heavy-metal based CCA.Didecyldimethylammonium chloride [DDAC] was...

  14. Molecular characterisation of birch bark tar by headspace solid-phase microextraction gas chromatography-mass spectrometry: a new way for identifying archaeological glues.

    Science.gov (United States)

    Regert, M; Alexandre, V; Thomas, N; Lattuati-Derieux, A

    2006-01-06

    To develop an analytical methodology, as non-destructive as possible, suitable for the identification of natural substances from archaeological origin, we studied the potentiality of solid-phase microextraction (SPME) for analysing birch bark tar, an adhesive commonly used during ancient times. First of all, birch bark tars were produced by a controlled heating of birch bark. The two kinds of samples obtained using different processes of fabrication, one at liquid state, the second one at solid state, were then analysed by headspace HS-SPME-GC-MS. Different conditions of sample treatment were tested (two different fibre coatings, various times and temperatures of extraction) in order to suggest optimal conditions for the analysis of birch bark tar. Both samples were shown to be rich in volatile organic components. Two main groups of constituents, namely phenolic compounds issued from lignin or tannin known to be present in bark and sesquiterpenoid hydrocarbons, secondary metabolites largely distributed in the plant kingdom, were detected for the first time in birch bark tar. HS-SPME-GC-MS appears thus to be a very efficient method for investigating the volatiles emitted by plant tars and could be further used for the study of birch bark tar samples issued from archaeological context.

  15. Fuel wood symposium; Symposium Energieholz

    Energy Technology Data Exchange (ETDEWEB)

    Wild, C.; Wauer, A. (comps.)

    2001-07-01

    The Bavarian State Institute of Forestry (LWF) organised a 'Fuel Wood Symposium' in Freising-Weihenstephan on 17.11.2000. The purpose of this specialist conference was to give an overview of the use of biomass, especially wood, as an source of energy. (orig.) [German] Die Bayerische Landesanstalt fuer Wald und Forstwirtschaft richtete am 17.11.2000 in Freising-Weihenstephan das 'Symposium Energieholz' aus. Ziel der Fachtagung war es, einen Ueberblick ueber die energetische Nutzung von Biomasse, insbesondere Holz, zu geben. (orig.)

  16. Comparative wood anatomy of Rhodothamnus species

    OpenAIRE

    SERDAR, Bedri

    2014-01-01

    In this study, the comparative wood anatomy of the European [Rhodothamnus chamaecistus (L.) Reichb.] and Anatolian (Rhodothamnus sessilifolius P.H.Davis) species of Rhodothamnus were studied. The wood anatomy of the taxa shows evidence of adaptation to growing in alpine habitats. The woods of the species exhibit primitive wood anatomical characteristics and share similar qualitative anatomical features. However, some of the quantitative anatomical characteristics of the taxa show significant ...

  17. Changes in expression of BetV1 allergen of silver birch pollen in urbanized area of Ukraine.

    Science.gov (United States)

    Žiarovská, Jana; Labajová, Mária; Ražná, Katarína; Bežo, Milan; Štefúnová, Veronika; Shevtsova, Tatiana; Garkava, Kateryna; Brindza, Ján

    2013-01-01

    The aim of the study was to determinate the level of expression of silver birch allergen Betv1 in pollen samples from different Ukraine areas by RT-qPCR SYBR Green assay. Protocol for quantifying the expression of Betv1 allergen was developed when testing of three housekeeping genes-cyclophylin, alpha-tubulin and transcription factor CBF1. Samples from urbanized area was analysed by real-time PCR when a sample from forest growth conditions was used as a calibrator. Real-time PCR based quantifying of Betv1 provides a useful method for rapid and sensitive analyses of this silver birch allergen. Our results show higher expression levels in samples from central parts of urbanized area as housing estates when compared to the samples from borders of the urbanized area.

  18. Composite structure of wood cells in petrified wood

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Jakub [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Florek, Marek [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Kwiatek, Wojciech [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Lekki, Janusz [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Chevallier, Pierre [LPS, CEN Saclay et LURE, Universite Paris-Sud, Bat 209D, F-91405 Orsay (France); Zieba, Emil [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Mestres, Narcis [Institut de Ciencia de Materials de Barcelona (ICMAB), Campus de la UAB, E-08193-Bellaterra (Spain); Dutkiewicz, E.M. [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Kuczumow, Andrzej [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland)

    2005-04-28

    Special kinds of petrified wood of complex structure were investigated. All the samples were composed of at least two different inorganic substances. The original cell structure was preserved in each case. The remnants of the original biological material were detected in some locations, especially in the cell walls. The complex inorganic structure was superimposed on the remnant organic network. The first inorganic component was located in the lumena (l.) of the cells while another one in the walls (w.) of the cells. The investigated arrangements were as follows: calcite (l.)-goethite-hematite (w.)-wood from Dunarobba, Italy; pyrite (l.)-calcite (w.)-wood from Lukow, Poland; goethite (l.)-silica (w.)-wood from Kwaczala, Poland. The inorganic composition was analysed and spatially located by the use of three spectral methods: electron microprobe, X-ray synchrotron-based microprobe, {mu}-PIXE microprobe. The accurate mappings presenting 2D distribution of the chemical species were presented for each case. Trace elements were detected and correlated with the distribution of the main elements. In addition, the identification of phases was done by the use of {mu}-Raman and {mu}-XRD techniques for selected and representative points. The possible mechanisms of the described arrangements are considered. The potential synthesis of similar structures and their possible applications are suggested.

  19. Mechanical Behaviour of the Wood Masonry

    Directory of Open Access Journals (Sweden)

    Fazia FOUCHAL

    2011-09-01

    Full Text Available In this paper we study the walls wood masonry behaviour. First, we propose a regulatory validation of the walls wood masonry behaviour subjected to vertical and horizontal loads according to Eurocode 5. Then we present the numerical application on the wall wood supported two floors level.

  20. Sustainable wood waste management in Nigeria

    Directory of Open Access Journals (Sweden)

    Owoyemi Jacob Mayowa

    2016-09-01

    Full Text Available Wood industries produce large volumes of residues which must be utilized, marketed or properly disposed of. Heaps of wood residues are common features in wood industries throughout the year. In Nigeria, this residue is generally regarded as waste and this has led to open burning practices, dumping in water bodies or dumping in an open area which constitutes environmental pollution. Sawmills in Nigeria generated over 1,000,000 m3 of wood waste in 2010 while about 5000 m3 of waste was generated in plywood mills. Nigeria generates about 1.8 million tons of sawdust annually and 5.2 million tons of wood wastes. The impact of improper disposal of waste wood on the environment affects both the aquatic and terrestrial ecosystems. Also burning of waste wood releases greenhouse gases into the atmosphere causing various health issues. Reuse/recycling of these wood residues in Nigeria will reduce the pressure on our ever decreasing forests, reduce environmental pollution, create wealth and employment. The literature available on this subject was reviewed and this article, therefore, focuses on the various methods of wood waste disposal and its utilization in Nigerian wood industries, the effects of wood waste on the environment as well as on human health and the benefits of proper wood waste management practices.

  1. WOOD COLOR CHANGES BY AMMONIA FUMING

    Directory of Open Access Journals (Sweden)

    Josip Miklečić,

    2012-06-01

    Full Text Available This paper studies the influence of ammonia gas on wood color changes in response to an increasing demand for dark colored wood specimens. The darker wood color in ammonia fuming is accomplished through chemical reactions between ammonia gas and wood compounds. We exposed oak, maple, spruce, and larch wood samples to ammonia gas for 16 days. During fuming, the color changes were studied using CIE L*a*b* parameters. After fuming, the changes in extractives content, tannin, and nitrogen content were analyzed. The chemical changes of wood and residues of wood extractives after fuming were analyzed by FTIR spectroscopy. Oak wood reacted intensively with ammonia gas in a very short time, and the darkening was prominent for all the investigated wood species. It was established that tannin had no major influence on color changes of maple and larch wood in the ammonia-fuming process. The FTIR spectra of fumed wood indicated involvement of carbonyl groups, and the FTIR spectra of wood extractives indicated involvement of carbonyl, aromatic, and alcohol groups in reaction with ammonia gas.

  2. Bioremediation of treated wood with fungi

    Science.gov (United States)

    Barbara L. Illman; Vina W. Yang

    2006-01-01

    The authors have developed technologies for fungal bioremediation of waste wood treated with oilborne or metal-based preservatives. The technologies are based on specially formulated inoculum of wood-decay fungi, obtained through strain selection to obtain preservative-tolerant fungi. This waste management approach provides a product with reduced wood volume and the...

  3. European wood-pastures in transition

    DEFF Research Database (Denmark)

    2014-01-01

    Wood-pastures are important elements of European cultural identity and have an exceptional ecological value, yet they are in decline all over Europe. The structure of wood-pastures is strongly influenced by grazing and multiple other land uses and by local and regional environmental conditions. T...... conservation policies and management approaches for wood-pastures....

  4. Biomass of Scots pine-silver birch tree stand 25 years after afforestation of former agricultural land

    OpenAIRE

    Deptuła, Miłosz; Nienartowicz, Andrzej; Iwicka, Marta; Filbrandt-Czaja, Anna

    2017-01-01

    : In 2O15, the structure of a forest stand growing on former agricultural land in subunit 277n of the Przymuszewo Forest Division (Regional Directorate of State Forests RDSF in Toruń) was described. The study area was afforested in 199O - mostly with Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth) and several seedlings of the European beech – after many years of agricultural cultivation of grain and potato crops. Characteristics of the forest stand comprised the following...

  5. Dissolved organic carbon and nitrogen leaching from Scots pine, Norway spruce and silver birch stands in southern Sweden

    OpenAIRE

    Fröberg, Mats; Hansson, Karna; Kleja, Dan Berggren; Alavi, Ghasem

    2011-01-01

    The effects of three common tree species – Scots pine, Norway spruce and silver birch – on leaching of dissolved organic carbon and dissolved nitrogen were studied in an experimental forest with podzolised soils in southern Sweden. We analyzed soil water collected with lysimeters and modeled water fluxes to estimate dissolved C and N fluxes. Specific UV absorbance (SUVA) was analyzed to get information about the quality of dissolved organic matter leached from the different stands. Under the ...

  6. Characterization of wild-type recombinant Bet v 1a as a candidate vaccine against birch pollen allergy.

    Science.gov (United States)

    Batard, Thierry; Didierlaurent, Alain; Chabre, Henri; Mothes, Nadine; Bussières, Laetitia; Bohle, Barbara; Couret, Marie-Noëlle; Ball, Tanja; Lemoine, Pierrick; Focks Tejkl, Margarete; Chenal, Alexandre; Clément, Gilles; Dupont, Francis; Valent, Peter; Krauth, Marie-Theres; André, Claude; Valenta, Rudolf; Moingeon, Philippe

    2005-03-01

    We describe the production in Escherichia coli as a recombinant protein of clinical grade wild-type Bet v 1a (rBet v 1a), to be used as a candidate vaccine against birch pollen allergy. This recombinant protein was purified by hydrophobic interaction and ion exchange chromatography and characterized by SDS-PAGE, immunoprint and circular dichroism in parallel with natural Bet v 1 (nBet v 1) purified from a birch pollen extract. We also compared rBet v 1 and nBet v 1 for their capacity to induce histamine release from basophils and to stimulate T lymphocyte proliferation. rBet v 1a appears in SDS-PAGE as an 18-kDa monomeric protein, whereas purified nBet v 1 comprises a mixture of isoforms (resolving as three distinct bands and six spots after 1-dimensional and 2-dimensional electrophoresis, respectively). Both recombinant and natural purified Bet v 1 molecules are recognized by IgE from birch pollen-allergic patients as well as anti-Bet v 1 murine monoclonal antibodies, suggesting that the recombinant protein is correctly folded in a native configuration. Circular dichroism analysis confirmed that the two Bet v 1 molecules exhibit similar 3-dimensional structures, even if rBet v 1a appears more compact and stable in thermodenaturation/renaturation experiments. Both rBet v 1 and nBet v 1 induce the degranulation of sensitized basophils and proliferation of Bet v 1-specific T lymphocytes in a similar manner. On the basis of these structural and biological properties, rBet v 1a is a valid candidate vaccine against birch pollen allergy, currently evaluated in humans. Copyright (c) 2005 S. Karger AG, Basel.

  7. Biomass and nutrient cycle in fertilized and unfertilized pine, mixed birch and pine and spruce stands on a drained mire.

    OpenAIRE

    Finér, Leena

    1989-01-01

    Biomass, biomass increment and nutrient cycling were studied in (1) a Scots pine (Pinus sylvestris) stand, (2) a Norway spruce (Picea abies) stand and (3) a mixed birch (Betula pubescens)/pine stand on a drained mire at Ilomantsi, eastern Finland in 1979-85. In addition, the effect of NPK and micronutrient fertilizer treatment was studied. Above-ground and root measurements were taken. These data formed the basis of stand biomass and nutrient cycle simulations of fertilized and unfertilized s...

  8. Bacillus coreaensis sp. nov.: a xylan-hydrolyzing bacterium isolated from the soil of Jeju Island, Republic of Korea.

    Science.gov (United States)

    Chi, Won-Jae; Youn, Young Sang; Park, Jae-Seon; Hong, Soon-Kwang

    2015-07-01

    A xylan-degrading bacterium, designated as MS5(T) strain, was isolated from soil collected from the Jeju Island, Republic of Korea. Strain MS5(T) was Gram-stain-positive, aerobic, and motile by polar flagellum. The major fatty acids identified in this bacterium were iso-C15:0 (32.3%), C16:0 (27.3%), and anteiso-C15:0 (10.2%). A similarity search based on the 16S rRNA gene sequence revealed that the strain belongs to the class Bacilli and shared the highest similarity with the type strains Bacillus beringensis BR035(T) (98.7%) and Bacillus korlensis ZLC-26(T) (98.6%) which form a coherent cluster in a neighbor-joining phylogenetic tree. The DNA G+C content of strain MS5(T) was 43.0 mol%. The major menaquinone was MK-7 and the diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The DNADNA relatedness values between strain MS5(T) and two closely related species, B. beringensis BR035(T) and B. korlensis ZLC-26(T), were less than 70%. DNA-DNA relatedness analysis and 16S rRNA sequence similarity, as well as phenotypic and chemotaxonomic characteristics suggest that the strain MS5(T) constitutes a novel Bacillus species, for which the name Bacillus coreaensis sp. nov. is proposed. The type strain is MS5(T) (=DSM25506(T) =KCTC13895(T)).

  9. Agar-agar entrapment increases the stability of endo-β-1,4-xylanase for repeated biodegradation of xylan.

    Science.gov (United States)

    Bibi, Zainab; Shahid, Faiza; Ul Qader, Shah Ali; Aman, Afsheen

    2015-04-01

    Microbial xylanases, specially endo-β-1,4-xylanase catalyzes the hydrolysis of xylan, is considered one of the most significant hydrolases. It has numerous applications but most extensively is utilized in paper and pulp industry as a bio-bleaching agent. Immobilization technique is comprehensively studied with the expectation of modifying and improving enzyme stability and characteristics for commercial purposes. Currently, matrix entrapment technique is applied to immobilize endo-β-1,4-xylanase within agar-agar gel beads produced by Geobacillus stearothermophilus KIBGE-IB29. Maximal enzyme immobilization yield was achieved at 2.5% of agar-agar concentration. Optimized conditions demonstrated an increase in the optimal reaction time from 05 min to 30 min and incubation temperature from 50 °C to 60 °C with reference to free enzyme whereas; no effect was observed for optimum pH. Entrapment technique uniquely changed the kinetic parameters of immobilized endo-β-1,4-xylanase (Km: 0.5074 mg min(-1) to 0.5230 mg min(-1) and Vmax: 4773 U min(-1) to 968 U min(-1)) as compared to free enzyme. However, immobilized enzyme displayed broad thermal stability and retained 79.0% of its initial activity at 80 °C up to 30 min whereas; free enzyme completely lost its activity at this temperature. With respect to economic feasibility, the immobilized enzyme showed impressive recycling efficiency up to six reaction cycles.

  10. The major birch pollen allergen Bet v 1 induces different responses in dendritic cells of birch pollen allergic and healthy individuals.

    Directory of Open Access Journals (Sweden)

    Ursula Smole

    Full Text Available Dendritic cells play a fundamental role in shaping the immune response to allergens. The events that lead to allergic sensitization or tolerance induction during the interaction of the major birch pollen allergen Bet v 1 and dendritic cells are not very well studied. Here, we analyzed the uptake of Bet v 1 and the cross-reactive celery allergen Api g 1 by immature monocyte-derived dendritic cells (iMoDCs of allergic and normal donors. In addition, we characterized the allergen-triggered intracellular signaling and transcriptional events. Uptake kinetics, competitive binding, and internalization pathways of labeled allergens by iMoDCs were visualized by live-cell imaging. Surface-bound IgE was detected by immunofluorescence microscopy and flow cytometry. Allergen- and IgE-induced gene expression of early growth response genes and Th1 and Th2 related cytokines and chemokines were analyzed by real-time PCR. Phosporylation of signaling kinases was analyzed by Western blot. Internalization of Bet v 1 by iMoDCs of both donor groups, likely by receptor-mediated caveolar endocytosis, followed similar kinetics. Bet v 1 outcompeted Api g 1 in cell surface binding and uptake. MoDCs of allergic and healthy donors displayed surface-bound IgE and showed a pronounced upregulation of Th2 cytokine- and NFκB-dependent genes upon non-specific Fcε receptor cross-linking. In contrast to these IgE-mediated responses, Bet v 1-stimulation increased transcript levels of the Th2 cytokines IL-4 and IL-13 but not of NFκB-related genes in MoDCs of BP allergic donors. Cells of healthy donors were either unresponsive or showed elevated mRNA levels of Th1-promoting chemokines. Moreover, Bet v 1 was able to induce Erk1/2 and p38 MAPK activation in BP allergics but only a slight p38 activation in normal donors. In conclusion, our data indicate that Bet v 1 favors the activation of a Th2 program only in DCs of BP allergic individuals.

  11. Wood Microstructure Effects on Chinese White Poplar Dyeing

    Institute of Scientific and Technical Information of China (English)

    DUANXinfang; BAOFucheng

    2004-01-01

    In order to study the influence of wood microstructure on wood dyeing, eleven parameters of wood microstructure and 5 parameters of wood dyeing effects for 34 pieces of wood boards from 5 trees of Chinese white poplar (Populus tornentosa) were determined and the multiple regression analysis between the factors of wood microstructures and the parameters of wood dyeing effects were made. The regression results show that each variable of wood dyeing effects has higher relationship with wood microstructures,and multiple correlation coefficients between each variable of wood dyeing effects and wood microstructures are 0.483 6-0.799 8. The main factors of wood microstructures influencing wood dyeing of Chinese whitep oplar are proportion of wood ray, proportion of vessel and proportion of wood fiber according to comparing the standardized regression coefficients of multiple regression equation.

  12. IMPACT OF THE EU TIMBER REGULATION ON RUSSIAN COMPANIES EXPORTING WOOD AND WOOD-BASED PRODUCTS

    OpenAIRE

    NESHATAEVA ELENA V.; KARJALAINEN TIMO

    2015-01-01

    The problem of illegal logging forced EU, which is one of the major consumers of wood in the world, to develop legislation aimed at termination of supplies of illegally harvested wood and wood-based products into EU. EU Timber Regulation №995 is applicable for any company placing wood or wood-based products on the EU market. Russia ranks first in illegally harvested timber export into EU markets, therefore EU Timber Regulation should influence substantially on Russian companies. Possible infl...

  13. Mathematical Simulation of Temperature Profiles within Microwave Heated Wood Made for Wood-Based Nanocomposites

    OpenAIRE

    Xianjun Li; Yongfeng Luo; Hongbin Chen; Xia He; Jianxiong Lv; Yiqiang Wu

    2013-01-01

    High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nanocomposites. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles within wood heated by high intensive microwave was established and simulated in this research. The results showed that the temperature profiles within wood were related to microwave heating methods; The temperature inside wood firstly increased and then gradually decreased al...

  14. Investigation into Physicochemical Properties of Xylan Derivatives with High Degree of Substitution%高取代度木聚糖衍生物的理化性质

    Institute of Scientific and Technical Information of China (English)

    彭新文; 任俊莉; 孙润仓

    2011-01-01

    Bifunctional xylan derivatives ( XDs) with high degree of substitution were prepared from native xylan in wheat straw, with acrylamide as the etherifying agent, alkali as the catalyst, and butanol/water mixture as the reaction system. Then, the structure of the products was characterized by means of 13 C NMR. Moreover, the dynamic rheological behaviors and thermal stability of XDs and the native xylan were tested by using a parallel-plate rheometer and a simultaneous thermal analyzer,respectively. The results show that,as compared with the native xylan, the shear-thinning phenomenon of XDs solution is significant, with relatively lower viscosity, storage modulus and loss modulus, that the storage modulus is higher than the loss modulus, and that the thermal stability of the xylan declines after the modification.%以从麦草中分离得到的木聚糖为原料、丙烯酰胺为醚化剂、碱为催化剂、丁醇/水为反应介质制备了带有高取代度双官能团的木聚糖衍生物.采用13C核磁共振表征了木聚糖衍生物的结构.利用平行板流变仪和同步热分析仪对木聚糖衍生物与原木聚糖的动态流变性能和热稳定性进行测试,结果表明:与原木聚糖溶液相比,木聚糖衍生物溶液呈现较低的粘度,剪切变稀的现象较明显,具有较低的储能模量、损耗模量,且其储能模量稍高于损耗模量;改性后的木聚糖的热稳定性下降.

  15. Impact of ectohumus application in birch and pine nurseries on the presence of soil mites (Acari, Oribatida in particular

    Directory of Open Access Journals (Sweden)

    Klimek Andrzej

    2016-03-01

    Full Text Available Intensively used forest nurseries are characterised by degradation processes that lead to a drop in the quality of seedlings. The main reason of this problem is a decrease in biological soil diversity. Therefore, an attempt of nursery soil enrichment by introducing ectohumus – as compost and fresh litter – from the pine forest was carried out. The research was carried out in 2009–2011 in the Bielawy forest nursery near the city of Toruń, Poland. The objective of the study was to determine the impact of organic fertilisation (compost made up of forest humus and mulching using fresh ectohumus on the density and community composition of Acari mites and on species composition of oribatid mites (Oribatida in the nurseries of silver birch and Scots pine. Mites, especially oribatid mites, were treated as bioindicators of soil biological activity. Research has shown that mulching using fresh ectohumus caused a multiple increase in the density of mites, especially in saprophagous mites Oribatida. Oribatid mites were clearly more numerous in birch cultivation than in that of pine. Overall, 27 species of oribatid mites were found. Mulching resulted in a significant growth in species diversity in both cultivations. The most numerous oribatid mite in the area under the study was Oribatula tibialis. This species was present in all plots and showed clear preference for birch cultivation. Tectocepheus velatus and Oppiella nova, common and known to be present in a variety of environments, were slightly less numerous.

  16. Optimization of ultrasonic-assisted extraction (UAE) of betulin from white birch bark using response surface methodology.

    Science.gov (United States)

    Chen, Qi-he; Fu, Ming-liang; Liu, Jin; Zhang, Hai-feng; He, Guo-qing; Ruan, Hui

    2009-06-01

    Betulin is an abundant naturally occurring triterpene, which makes it a potentially important raw material for a precursor of biologically active compounds. The objective of the current study was to determine the optimum UAE conditions for betulin from B. papyfera bark. The optimum conditions were evaluated with fractional factorial design and optimized using response surface methodology. High yields of betulin were observed from white birch bark by UAE technology. The solvent concentration and the ratio of material to solvent were the most significant parameters on betulin extraction as evaluated through FFD. The extraction conditions were further investigated with central composite design. The fitted second-order model revealed that the optimal conditions consisted of 98% ethonal concentration, 1:42 the ratio of white birch bark to solvent, extraction temperature 50 degrees C, ultrasonic frequency 5kHz and extraction time 3h. Under the optimized condition, the maximum productivity of betulin predicted is 23.17%. The extraction productivity and purity of betulin under the optimized extraction conditions were great higher than that of the non-optimized condition. The present study demonstrates that ultrasound is a great efficiency tool for the fast extraction of betulin from white birch bark.

  17. Effects of long-term elevated ultraviolet-B radiation on phytochemicals in the bark of silver birch (Betula pendula)

    Energy Technology Data Exchange (ETDEWEB)

    Tegelberg, R.; Julkunen-Tiitto, R. [Joensuu Univ., Dept. of Biology, Joensuu (Finland); Aphalo, P. J. [Joensuu Univ., Faculty of Forestry, Joensuu (Finland)

    2002-12-01

    The effects of long-term ultraviolet-B radiation on the concentrations of secondary metabolites such as phenolics and terpenoids in the bark of silver birch saplings were studied. The effects of ultraviolet-B on the concentrations of the main soluble sugars such as sucrose, raffinose, and glucose in silver birch stem were also investigated, given that they are involved in the transpiration and allocation of assimilated carbon, and UV-B-induced changes may affect tree growth. Concentrations of sucrose, raffinose and glucose in bark were found to be higher in UV-treated saplings than in saplings grown in ambient radiation, indicating that stem carbohydrate metabolism was changed by long-term exposure to elevated UV radiation. Saplings in elevated UV-A + UV-B radiation treatment and UV-A radiation control treatment had shown significantly increased concentrations of certain UV-absorbing phenolics compared with saplings in ambient radiation. No effect of radiation treatment was observed on non-UV-B-absorbing terpenoids. These observations led to the conclusion that plant parts accumulate specific phenolic UV-filters in response to UV radiation exposure. The accumulation of sugars in the stems of silver birch saplings in response to UV radiation is believed to affect tree growth, possibly because of a reduction of alpha-cellulose content and consequent reduction in cell wall production. 36 refs., 1 tab., 2 figs.

  18. Features of secondary birch young stands in low mountain Pokuttya (Ukrainian Carpathian mts.

    Directory of Open Access Journals (Sweden)

    S. Y. Milevskaya

    2015-06-01

    Full Text Available Forest landscapes of the region during the last 3–5 centuries undergone the profound anthropogenic transformation. Secondary young stands occupy 25% of the total forest area. The problem of derivatives is particularly relevant for the modern forest typology in the Carpathian region. It requires the reflection in its dynamic trends shaping the stands, especially mixed young stands. The aim of our study consisted in getting the knowledge of the structural features of the secondary phytocoenosis of birch young stands in this area.The object of the study was age class I saplings growing in the mountainous part of Pokuttya, particularly in the basin of the Lutshka River. The conceptual basis of our study is the modern dynamic vision that every forest type is a consecutive series of forest plant communities within each type of homogeneous growing conditions. We apply methods of ecological-floristic research of the Brown-Blanke school in the interpretation of the Polish school phytosociology. However we also take into account both syntaxonomy generalizations of the Ukrainian scientists. The actual material comprises the original geobotanical studies with fixation of the vast majority of species in plant communities. Mainly the species having diagnostic value to separate syntaxons were taken into account in the analytical processing. Young forest stands (with the height of 8–12 m and crown cover of 70% together form the trees Betula pendula and B. pubescens. Fairly numerous admixture is formed by trees Alnus incana; besides, there are Fagus sylvatica, Populus tremula, Quercus robur, Padus avium. For dominants, they can be called “grey-alder birch blackberry sedge bracken fern” – Betula pendula+Alnus incana–Rubus caesius–Carex brizoides+Pteridium aquilinum. It is rich in floristic composition of the plant communities. They contain at least 12 species of trees, 3 species of shrubs, 4 species of bushes and 89 species of herbs. Diagnostic

  19. Body of Wood

    Directory of Open Access Journals (Sweden)

    Pierre Michon

    2014-12-01

    not only a defrocked friar with the guys or on the street; he donned the silk babouches when he went home too. He dispossessed himself of the Seine that rolled on before his eyes; the small girl who lived on her feet, whom he puts to death in all his books, he hardly saw her; the loveliest girls of his day, the finest too for sure, who wanted him, so that he happened to come – he dispossessed himself of them, whether he came or opted to come no more, which amounted to the same thing; no apples from Norman orchards, no trees deep in the woods, no unlaced Louise Colet, no lilies, no young laughter, no Louise Colet weeping at his door, he kissed it all off, laughed over it and kissed it off, cried about it and kissed it off, he was not there. In fact he had nothing, he was deprived of everything, since it was in his head.

  20. Non-malignant respiratory diseases and occupational exposure to wood dust. Part I. Fresh wood and mixed wood industry.

    Science.gov (United States)

    Jacobsen, Gitte; Schaumburg, Inger; Sigsgaard, Torben; Schlunssen, Vivi

    2010-01-01

    This paper reviews associations in literature between exposure to wood dust from fresh wood and non-malignant respiratory diseases. Criteria for inclusion are epidemiological studies in English language journals with an internal or external control group describing relationships between wood dust exposure and respiratory diseases or symptoms. The papers took into account smoking, and when dealing with lung function took age into consideration. A total of 25 papers concerning exposure to fresh wood and mixed wood formed the basis of this review. The results support an association between fresh wood dust exposure and asthma, asthma symptoms, coughing, bronchitis, and acute and chronic impairment of lung function. In addition, an association between fresh wood dust exposure and rhino-conjunctivitis was seen across studies. Apart from plicatic acid in western red cedar wood, no causal agent was consistently disclosed. Type 1 allergy is not suspected of being a major cause of wood dust induced asthma. Concurrent exposure to microorganisms and terpenes probably add to the inherent risk of wood dust exposure in the fresh wood industry.

  1. Wood stoves: the trendy pollutant

    Energy Technology Data Exchange (ETDEWEB)

    Allaby, M.; Lovelock, J.

    1980-11-13

    The wood-burning stove is being increasingly accepted as an alternative to costly and scarce heating fuels. These stoves, however, contribute significantly to air pollution. The more efficient the stove, the more pollutants it releases. Carbon monoxide and hydrocarbons are the primary offenders. Increasing use of these stoves may also exhaust timber and forest resources. (3 drawings, 2 photos)

  2. Wood anatomy of the Combretaceae

    NARCIS (Netherlands)

    Vliet, van G.J.C.M.

    1979-01-01

    The wood anatomy of all genera of the Combretaceae (Meiostemon excepted) is described in detail on the basis of 120 samples representing 90 species from 19 genera. Additional data from the literature are added. The structural variation of the vestured pits is described and classified. There are two

  3. Biosynthesis and biodegradation of wood components

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, T. (ed.)

    1985-01-01

    A textbook containing 22 chapters by various authors covers the structure of wood, the localization of polysaccharides and lignins in wood cell walls, metabolism and synthetic function of cambial tissue, cell organelles and their function in the biosynthesis of cell wall components, biosynthesis of plant cell wall polysaccharides, lignin, cutin, suberin and associated waxes, phenolic acids and monolignols, quinones, flavonoids, tannins, stilbenes and terpenoid wood extractives, the occurrence of extractives, the metabolism of phenolic acids, wood degradation by micro-organisms and fungi, and biodegradation of cellulose, hemicelluloses, lignin, and aromatic extractives of wood. An index is included.

  4. Health risks of residential wood heat

    Science.gov (United States)

    Travis, Curtis C.; Etnier, Elizabeth L.; Meyer, H. Robert

    1985-05-01

    The resurgence in the use of wood in the United States for residential heating has been accompanied by a dramatic increase in deaths and injuries from residential fires. Toxic materials present in woodsmoke also appear to present a significant public health hazard. As a result of these factors, production of residential wood heat can be up to two orders of magnitude more hazardous than generation of an equivalent amount of electric energy at a coal-fired power plant. Proper care in installation and operation of wood stoves, as well as technological innovations that control wood-stove emissions, can greatly reduce the health and safety hazards of residential heating with wood.

  5. INTERACTION OF COPPER BASED PRESERVATIVES WITH WOOD

    Directory of Open Access Journals (Sweden)

    Ali Temiz

    2004-11-01

    Full Text Available Copper is highly toxic to fungi and the element is widely used in many preservative formulations over 50 years. The interactions of wood and copper-based preservatives impact both the performance and the environment aspects of treated wood. Copper might be present in treated wood as coppercellulose complex, copper-lignin complex, and crystalline or amorphous inorganic/organic copper compounds. In this review; it was aimed to investigate the interactions of wood and copper-based preservatives, Copper Adsorpsion factors and copper forms in treated wood

  6. Kinetic investigation of wood pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Thurner, F.; Mann, U.; Beck, S. R.

    1980-06-01

    The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

  7. Methane consumption and soil respiration by a birch forest soil in West Siberia

    Science.gov (United States)

    Nakano, Tomoko; Inoue, Gen; Fukuda, Masami

    2004-07-01

    Methane and carbon dioxide fluxes were measured in a birch forest soil in West Siberia, in August 1999, June 2000 and September 2000. The study site had a very thick organic horizon that was subject to drought during the observation periods. The soils always took up CH4, while CO2 was released from the surface to the atmosphere. CH4 consumption and CO2 emission rates ranged from 0.092 to 0.28 mg C m2 h1 and from 110 to 400 mg C m2 h1 respectively. The CH4 consumption rate and soil temperatures showed significant relationships for individual measurements. The soil respiration rate was weakly correlated with individual soil temperatures. This study examined the effect of current and lagged soil temperatures at a depth of 5 cm on CH4 consumption and soil respiration. The variation in the correlation coefficient between CH4 consumption and lagged soil temperature was greatest at a 4-h lag, whereas that for soil respiration showed a gentle peak at lags from several hours to half a day. This difference in the temperature-related lag effect between CH4 consumption and soil respiration results from differences in the exchange processes. Neither flux showed any correlation with soil moisture. The limited variation in soil moisture during our observation period may account for the lack of correlation. However, the droughty soil conditions resulted in high gas diffusion and, consequently, high CH4 consumption.

  8. The influence of recombinant production on the immunologic behavior of birch pollen isoallergens.

    Directory of Open Access Journals (Sweden)

    Michael Wallner

    Full Text Available BACKGROUND: Allergic reactions towards the birch major pollen allergen Bet v 1 are among the most common causes of spring pollinosis in the temperate climate zone of the Northern hemisphere. Natural Bet v 1 is composed of a complex mixture of different isoforms. Detailed analysis of recombinant Bet v 1 isoforms revealed striking differences in immunologic as well as allergenic properties of the molecules, leading to a classification of Bet v 1 isoforms into high, medium, and low IgE binding proteins. Especially low IgE binding Bet v 1 isoforms have been described as ideal candidates for desensitizing allergic patients with allergen specific immunotherapy (SIT. Since diagnosis and therapy of allergic diseases are highly dependent on recombinant proteins, continuous improvement of protein production is an absolute necessity. METHODOLOGY: Therefore, two different methods for recombinant production of a low IgE binding Bet v 1 isoform were applied; one based on published protocols, the other by implementing latest innovations in protein production. Both batches of Bet v 1.0401 were extensively characterized by an array of physicochemical as well as immunological methods to compare protein primary structure, purity, quantity, folding, aggregation state, thermal stability, and antibody binding capacity. CONCLUSION: The experiments demonstrated that IgE antibody binding properties of recombinant isoallergens can be significantly influenced by the production method directly affecting possible clinical applications of the molecules.

  9. Detection of Malware and Malicious Executables Using E-Birch Algorithm

    Directory of Open Access Journals (Sweden)

    Dr. Ashit Kumar Dutta

    2016-01-01

    Full Text Available Malware detection is one of the challenges to the modern computing world. Web mining is the subset of data mining used to provide solutions for complex problems. Web intelligence is the new hope for the field of computer science to bring solution for the malware detection. Web mining is the method of web intelligence to make web as an intelligent tool to combat malware and phishing websites. Generally, malware injected through websites into the user system and modifies the executable file and paralyze the whole activity of the system. Antivirus application utilizes the data mining technique to find the malware in the web. There is a need of heuristic approach to solve the malware problem. Dynamic analysis methods yield better result than the static methods. Data mining is the best option for the dynamic analysis of malware or malicious program. The purpose of the research is to apply the enhanced Birch algorithm to find the malware and modified executables of Windows and Android operating system.

  10. Analysis of Individual Tree Competition Effect on Diameter Growth of Silver Birch in Estonia

    Directory of Open Access Journals (Sweden)

    Kobra Maleki

    2015-08-01

    Full Text Available Aim of study: The present study evaluates a set of competition indices including spatially explicit indices combined with different competitor selection approaches and non-spatially explicit competition indices. The aim was to quantify and describe the neighbouring effects on the tree diameter growth of silver birch trees. Area of study: Region throughout Estonia. Material and methods: Data from the Estonian Network of Forest Research Plots was used. After quantifying the selected indices, the best non-spatial indices and spatial indices (combined with neighbour selection methods were separately devised into a growth model as a predictor variable to assess the ability of the diameter growth model before and after adding competition measures. To test the species-specific effect on the competition level, the superior indices were recalculated using Ellenberg’s light indicators and incorporated into the diameter growth model. Main results: Statistical analyses showed that the diameter growth is a function of neighbourhood interactions and spatial indices were better growth predictors than non-spatial indices. In addition, the best selections of competitive neighbours were acquired based on the influence zone and the competition elimination angle concepts, and using Ellenberg’s light values had no significant improvement in quantifying the competition effects. Research highlights: Although the best ranking spatial competition measures were superior to the best non-spatial indices, the differences were negligible.

  11. Artificially decreased vapour pressure deficit in field conditions modifies foliar metabolite profiles in birch and aspen.

    Science.gov (United States)

    Lihavainen, Jenna; Keinänen, Markku; Keski-Saari, Sarita; Kontunen-Soppela, Sari; Sõber, Anu; Oksanen, Elina

    2016-07-01

    Relative air humidity (RH) is expected to increase in northern Europe due to climate change. Increasing RH reduces the difference of water vapour pressure deficit (VPD) between the leaf and the atmosphere, and affects the gas exchange of plants. Little is known about the effects of decreased VPD on plant metabolism, especially under field conditions. This study was conducted to determine the effects of artificially decreased VPD on silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L.×P. tremuloides Michx.) foliar metabolite and nutrient profiles in a unique free air humidity manipulation (FAHM) field experiment during the fourth season of humidity manipulation, in 2011. Long-term exposure to decreased VPD modified nutrient homeostasis in tree leaves, as demonstrated by a lower N concentration and N:P ratio in aspen leaves, and higher Na concentration and lower K:Na ratio in the leaves of both species in decreased VPD than in ambient VPD. Decreased VPD caused a shift in foliar metabolite profiles of both species, affecting primary and secondary metabolites. Metabolic adjustment to decreased VPD included elevated levels of starch and heptulose sugars, sorbitol, hemiterpenoid and phenolic glycosides, and α-tocopherol. High levels of carbon reserves, phenolic compounds, and antioxidants under decreased VPD may modify plant resistance to environmental stresses emerging under changing climate.

  12. Ligand Binding Modulates the Structural Dynamics and Compactness of the Major Birch Pollen Allergen

    Science.gov (United States)

    Grutsch, Sarina; Fuchs, Julian E.; Freier, Regina; Kofler, Stefan; Bibi, Marium; Asam, Claudia; Wallner, Michael; Ferreira, Fátima; Brandstetter, Hans; Liedl, Klaus R.; Tollinger, Martin

    2014-01-01

    Pathogenesis-related plant proteins of class-10 (PR-10) are essential for storage and transport of small molecules. A prominent member of the PR-10 family, the major birch pollen allergen Bet v 1, is the main cause of spring pollinosis in the temperate climate zone of the northern hemisphere. Bet v 1 binds various ligand molecules to its internal cavity, and immunologic effects of the presence of ligand have been discussed. However, the mechanism of binding has remained elusive. In this study, we show that in solution Bet v 1.0101 is conformationally heterogeneous and cannot be represented by a single structure. NMR relaxation data suggest that structural dynamics are fundamental for ligand access to the protein interior. Complex formation then leads to significant rigidification of the protein along with a compaction of its 3D structure. The data presented herein provide a structural basis for understanding the immunogenic and allergenic potential of ligand binding to Bet v 1 allergens. PMID:25517162

  13. Prediction of the birch pollen season characteristics in Cracow, Poland using an 18-year data series.

    Science.gov (United States)

    Dorota, Myszkowska

    2013-03-01

    The aim of the study was to construct the model forecasting the birch pollen season characteristics in Cracow on the basis of an 18-year data series. The study was performed using the volumetric method (Lanzoni/Burkard trap). The 98/95 % method was used to calculate the pollen season. The Spearman's correlation test was applied to find the relationship between the meteorological parameters and pollen season characteristics. To construct the predictive model, the backward stepwise multiple regression analysis was used including the multi-collinearity of variables. The predictive models best fitted the pollen season start and end, especially models containing two independent variables. The peak concentration value was predicted with the higher prediction error. Also the accuracy of the models predicting the pollen season characteristics in 2009 was higher in comparison with 2010. Both, the multi-variable model and one-variable model for the beginning of the pollen season included air temperature during the last 10 days of February, while the multi-variable model also included humidity at the beginning of April. The models forecasting the end of the pollen season were based on temperature in March-April, while the peak day was predicted using the temperature during the last 10 days of March.

  14. Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen

    Directory of Open Access Journals (Sweden)

    B. G. Pummer

    2012-03-01

    Full Text Available The ice nucleation of bioaerosols (bacteria, pollen, spores, etc. is a topic of growing interest, since their impact on ice cloud formation and thus on radiative forcing, an important parameter in global climate, is not yet fully understood. Here we show that pollen of different species strongly differ in their ice nucleation behaviour. The average freezing temperatures in laboratory experiments range from 240 to 255 K. As the most efficient nuclei (silver birch, Scots pine and common juniper pollen have a distribution area up to the Northern timberline, their ice nucleation activity might be a cryoprotective mechanism. Far more intriguingly, it has turned out that water, which has been in contact with pollen and then been separated from the bodies, nucleates as good as the pollen grains themselves. The ice nuclei have to be easily-suspendable macromolecules located on the pollen. Once extracted, they can be distributed further through the atmosphere than the heavy pollen grains and so presumably augment the impact of pollen on ice cloud formation even in the upper troposphere. Our experiments lead to the conclusion that pollen ice nuclei, in contrast to bacterial and fungal ice nucleating proteins, are non-proteinaceous compounds.

  15. Formic acid aided hot water extraction of hemicellulose from European silver birch (Betula pendula) sawdust.

    Science.gov (United States)

    Goldmann, Werner Marcelo; Ahola, Juha; Mikola, Marja; Tanskanen, Juha

    2017-05-01

    Hemicellulose has been extracted from birch (Betula pendula) sawdust by formic acid aided hot water extraction. The maximum amount of hemicellulose extracted was about 70mol% of the total hemicellulose content at 170°C, measured as the combined yield of xylose and furfural. Lower temperatures (130 and 140°C) favored hemicellulose hydrolysis rather than cellulose hydrolysis, even though the total hemicellulose yield was less than at 170°C. It was found that formic acid greatly increased the hydrolysis of hemicellulose to xylose and furfural at the experimental temperatures. The amount of lignin in the extract remained below the detection limit of the analysis (3g/L) in all cases. Formic acid aided hot water extraction is a promising technique for extracting hemicellulose from woody biomass, while leaving a solid residue with low hemicellulose content, which can be delignified to culminate in the three main isolated lignocellulosic fractions: cellulose, hemicellulose, and lignin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Influence of Birch Bark Triterpenes on Keratinocytes and Fibroblasts from Diabetic and Nondiabetic Donors.

    Science.gov (United States)

    Wardecki, Tina; Werner, Philipp; Thomas, Maria; Templin, Markus F; Schmidt, Gudula; Brandner, Johanna M; Merfort, Irmgard

    2016-04-22

    Impaired wound healing is one of the main risk factors associated with diabetes mellitus. Few options are available to treat diabetic wounds, and therefore efficient remedies are urgently needed. An interesting option might be an extract of birch bark (TE) that has been clinically proven to accelerate acute wound healing. We investigated the effects of TE and its main components betulin and lupeol in cultured normal keratinocytes and dermal fibroblasts from diabetic and nondiabetic donors. These in vitro models can provide insights into possible beneficial effects in wound healing. TE and betulin treatment led to increased mRNA levels of chemokines, pro-inflammatory cytokines, and mediators important in wound healing, e.g., IL-6, TNFα, IL-8, and RANTES. We observed a pronounced upregulation of MIF, IL-8, and RANTES on the protein level. Furthermore, a shape change of the actin cytoskeleton was seen in keratinocytes and fibroblasts, and the Rho-GTPases and p38-MAPK were found to be activated in keratinocytes. On the basis of our results, TE is worthy of further study as a potential option to influence wound-healing processes under diabetic conditions. These first insights need to be confirmed by clinical studies with diabetic patients.

  17. Quantification of C uptake in subarctic birch forest after setback by an extreme insect outbreak

    Science.gov (United States)

    Heliasz, Michal; Johansson, Torbjörn; Lindroth, Anders; Mölder, Meelis; Mastepanov, Mikhail; Friborg, Thomas; Callaghan, Terry V.; Christensen, Torben R.

    2011-01-01

    The carbon dynamics of northern natural ecosystems contribute significantly to the global carbon balance. Periodic disturbances to these dynamics include insect herbivory. Larvae of autumn and winter moths (Epirrita autumnata and Operophtera brumata) defoliate mountain birch (Betula pubescens) forests in northern Scandinavia cyclically every 9-10 years and occasionally (50-150 years) extreme population densities can threaten ecosystem stability. Here we report impacts on C balance following a 2004 outbreak where a widespread area of Lake Torneträsk catchment was severely defoliated. We show that in the growing season of 2004 the forest was a much smaller net sink of C than in a reference year, most likely due to lower gross photosynthesis. Ecosystem respiration in 2004 was smaller and less sensitive to air temperature at nighttime relative to 2006. The difference in growing season uptake between an insect affected and non-affected year over the 316 km2 area is in the order of 29 × 103 tonnes C equal to a reduction of the sink strength by 89%.

  18. [Wood dust as inhalative noxious agent].

    Science.gov (United States)

    Kirsten, D; Liebetrau, G; Meister, W

    1985-01-01

    Wood dust is known as a cause of asthma and chronic bronchitis. From 1979 to 1983 we observed 115 patients with chronic lung diseases, who were exposed to wood dust during many years. We found an irritative pathogenesis in 101 patients with asthma or bronchitis. Twenty nine patients had got a positive skin test, especially with makoré, beech, koto, ash, pine. The inhalation test was positive in 7 of them. The occupational etiology was verified in 5 patients. Besides wood dust itself chemicals for wood protection or wood adhesives can have importance in the pathogenesis of these diseases. Fourteen patients had got alveolitis or lung fibrosis after wood-dust exposition. In each case we found precipitating antibodies against moulds, which could be cultivated from wood dust to which the patients were exposed.

  19. Lung function in Pakistani wood workers.

    Science.gov (United States)

    Meo, Sultan A

    2006-06-01

    The lung function impairment is the most common respiratory problem in industrial plants and their vicinity. Therefore, the purpose was to study the affects of wood dust and its duration of exposure on lung function. This was a matched cross-sectional study of Spirometry in 46 non-smoking wood workers with age range 20 - 60 years, who worked without the benefit of wood dust control ventilation or respiratory protective devices. Pulmonary function test was performed by using an electronic Spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), and Maximum Voluntary Ventilation (MVV) in wood workers relative to their matched controls. This impairment was increased with the duration of exposure to wood industries. It is concluded that lung function in wood workers is impaired and stratification of results shows a dose-response effect of years of wood dust exposure on lung function.

  20. Wood ingestion by passalid beetles in the presence of xylose-fermenting gut yeasts.

    Science.gov (United States)

    Suh, Sung-Oui; Marshall, Christopher J; McHugh, Joseph V; Blackwell, Meredith

    2003-11-01

    During a survey of insect gut micro-organisms, we consistently isolated Pichia stipitis-like yeasts (Fungi: Ascomycota, Saccharomycetes) from the wood-ingesting beetles, Odontotaenius disjunctus and Verres sternbergianus (Coleoptera: Passalidae). The yeasts were isolated from passalid beetles over a wide area, including the eastern and midwestern USA and Panama. Phylogenetic analyses of the nuclear encoded small and large subunit rRNA gene (rDNA) sequences distinguished a well-supported clade consisting of the passalid yeasts and Pichia stipitis, P. segobiensis, Candida shehatae and C. ergatensis. Members of this clade have the ability to ferment and assimilate xylose or to hydrolyse xylan, major components of the polysaccharide, hemicellulose. Sexual reproduction was present in the passalid isolates but was rare among the gut yeasts of other beetles to which they were compared. Minor genetic and phenotypic variation among some of the passalid yeasts was detected using markers from the internal transcribed spacer region of the rDNA repeat unit, morphology, and in vitro metabolic tests. The consistent association of xylose-fermenting yeasts of almost identical genotypes with passalid beetles across a broad geographical distribution, suggests a significant symbiotic association.

  1. Functional characterization of CCR in birch (Betula platyphylla × Betula pendula) through overexpression and suppression analysis.

    Science.gov (United States)

    Zhang, Wenbo; Wei, Rui; Chen, Su; Jiang, Jing; Li, Huiyu; Huang, Haijiao; Yang, Guang; Wang, Shuo; Wei, Hairong; Liu, Guifeng

    2015-06-01

    We cloned a Cinnamoyl-CoA Reductase gene (BpCCR1) from an apical meristem and first internode of Betula platyphylla and characterized its functions in lignin biosynthesis, wood formation and tree growth through transgenic approaches. We generated overexpression and suppression transgenic lines and analyzed them in comparison with the wild-type in terms of lignin content, anatomical characteristics, height and biomass. We found that BpCCR1 overexpression could increase lignin content up to 14.6%, and its underexpression decreased lignin content by 6.3%. Surprisingly, modification of BpCCR1 expression led to conspicuous changes in wood characteristics, including xylem vessel number and arrangement, and secondary wall thickness. The growth of transgenic trees in terms of height was also significantly influenced by the modification of BpCCR1 genes. We discuss the functions of BpCCR1 in the context of a phylogenetic tree built with CCR genes from multiple species.

  2. Combustion of furniture wood waste and solid wood: Kinetic study and evolution of pollutants

    OpenAIRE

    Moreno Caballero, Ana Isabel; Font Montesinos, Rafael; Conesa, Juan A.

    2017-01-01

    This work is focused on the combustion processes of wood waste. Two kinds of waste have been studied: furniture wood waste (treated and used wood) and solid wood from factories (untreated wood). A kinetic study has been carried out for each material in air and an N2:O2 9:1 atmosphere with dynamic and dynamic + isothermal runs at different heating rates, considering the decomposition of the three main components of the wood and also the combustion of the char obtained. Satisfactory kinetic mod...

  3. Disinfection of foot-and-mouth disease and African swine fever viruses with citric acid and sodium hypochlorite on birch wood carriers

    Science.gov (United States)

    Transboundary animal disease viruses such as foot-and-mouth disease virus (FMDV) and African swine fever virus (ASFV) are highly contagious and cause severe morbidity and mortality in livestock. Proper disinfection during an outbreak can help prevent virus spread and will shorten the time for contam...

  4. 酸性染料在桦木中的渗透与吸附%Permeability and Adsorption of Acid Dyes in Birch Wood

    Institute of Scientific and Technical Information of China (English)

    韦双颖; 王砥; 顾继友

    2008-01-01

    采用扫描电镜和傅立叶变换红外光谱分析手段研究了木材染色过程中染料在桦木中的渗透与附着过程:当染料质量分数较高时,在放大1 500倍的SEM照片中观察到大量染料分子发生聚集,较多地吸附在单板表层;而当染料质量分数较低时,则观察不到染料分子.这种情况同时发生在单板芯层.在试验中,用肉眼观察到的颜色变化证明了单板已经吸附了染料分子.通过对染色过程中酸性橙Ⅱ的脱附和FTIR谱图分析可以推断,酸性橙Ⅱ与桦木的结合是以物理吸附为主,但这种吸附力较弱,染料较易流失.

  5. WOOD BIOMASS FOR ENERGY IN MONTENEGRO

    Directory of Open Access Journals (Sweden)

    Gradimir Danon

    2010-01-01

    Full Text Available Wood biomass has got its place in the energy balance of Montenegro. A little more than 6% of the total energy consumption is obtained by burning wood. Along with the appropriate state measures, it is economically and environmentally justified to expect Montenegro to more than double the utilization of the existing renewable energy sources including wood biomass, in the near future. For the purpose of achieving this goal, ‘Commercial Utilisation of the Wood Residue as a Resource for Economic Development in the North of Montenegro' project was carried out in 2007. The results of this project were included in the plan of the necessary interventions of the Government and its Agencies, associations or clusters, non-government organisations and interested enterprises. The plan was made on the basis of the wood residue at disposal and the attitude of individual subjects to produce and/or use solid bio-fuels and consists of a proposal of collection and utilisation of the wood residue for each individual district in the north of Montenegro. The basic factors of sustainability of future commercialisation of the wood residue were: availability of the wood raw material, and thereby the wood residue; the development of wood-based fuel markets, and the size of the profit.

  6. Wood-burning stoves worldwide

    DEFF Research Database (Denmark)

    Luis Teles de Carvalho, Ricardo

    , the advanced gasifiers and automatic stoves (Digital and Forced air) were identified to be among the best performing technologies. In spite of the fact that the thermal efficiency of the most advanced type of heating stoves (Gasifier) is around twice larger than that achieved for the most advanced type......More than any time in our history, the wood-burning stove continues to be the most popular technology used for cooking and heating worldwide. According to the World Health Organization and recent scientific studies, the inefficient use of solid-fuels in traditional stoves constitutes the major...... global environmental health risk, since these sources are important contributors to fine particulate matter (PM2.5) in the ambient air that increase climate and health risks. This thesis explores the social-technical dimensions of both the use of wood-burning stoves (WBSs) and transition to the use...

  7. Discover the benefits of residential wood heating

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This publication described how residential wood-heating systems are being used to reduce energy costs and increase home comfort. Biomass energy refers to all forms are renewable energy that is derived from plant materials. The source of fuel may include sawmills, woodworking shops, forest operations and farms. The combustion of biomass is also considered to be carbon dioxide neutral, and is not considered to be a major producer of greenhouse gases (GHG) linked to global climate change. Wood burning does, however, release air pollutants, particularly if they are incompletely burned. Incomplete combustion of wood results in dense smoke consisting of toxic gases. Natural Resources Canada helped create new safety standards and the development of the Wood Energy Technical Training Program to ensure that all types of wood-burning appliances are installed correctly and safely to reduce the risk of fire and for effective wood heating. In Canada, more than 3 million families heat with wood as a primary or secondary heating source in homes and cottages. Wood heating offers security from energy price fluctuations and electrical power failures. This paper described the benefits of fireplace inserts that can transform old fireplaces into modern heating systems. It also demonstrated how an add-on wood furnace can be installed next to oil furnaces to convert an oil-only heating system to a wood-oil combination system, thereby saving thousands of dollars in heating costs. Wood pellet stoves are another wood burning option. The fuel for the stoves is produced from dried, finely ground wood waste that is compressed into hard pellets that are loaded into a hopper. The stove can run automatically for up to 24 hours. New high-efficiency advanced fireplaces also offer an alternative heating system that can reduce heating costs while preserving Canada's limited supply of fossil fuels such as oil and gas. 13 figs.

  8. International Transmission Under Bretton Woods

    OpenAIRE

    Alan C. Stockman

    1992-01-01

    This paper explores the main channels of international transmission of economic disturbances under the Bretton Woods System and presents evidence on the short-run international transmission of inflation under that system. There appears to have been little short-run international transmission of inflation. Countries with one-percent higher money-growth rates subsequently had one-fourth to one-half percent higher inflation and a (predictably) lower real interest rate. This probably reflects eff...

  9. Nonisothermal moisture movement in wood

    Institute of Scientific and Technical Information of China (English)

    LI Xianjun; ZHANG Biguang; LI Wenjun; LI Yanjun

    2006-01-01

    In order to analyze the effect of temperature gradient on moisture movement during highly intensive drying,such as microwave-vacuum drying,the profile of the temperature and moisture content in sealed wood whose opposite faces were subjected to temperature gradient for a short time was measured.The ratio of the moisture content (MC) gradient to the temperature gradient (dM/dT) was calculated and the factors influencing moisture movement under nonisothermal conditions were discussed.The results indicate that moisture moved in wood from the warm surface to the cold one even if opposite faces of the sealed wood assembly were exposed continuously to different but constant temperatures for a short period.The moisture content on the cold surface was higher than that on the warm surface.The moisture content gradient opposite to the temperature gradient was established,and the dM/dT was below 0.9%/℃.The temperature in the sample and the distance from the hot surface of the sample was strongly linearly correlated.With an increase in temperature,initial moisture content and experimental time,the dM/dT was significantly increased.

  10. 超声波辅助碱法制备玉米芯木聚糖%Production of xylan from corncobs by ultrasound -assisted alkali method

    Institute of Scientific and Technical Information of China (English)

    孙军涛

    2015-01-01

    Xylan from corncobs was obtained by the method of high temperature pretreatment and ultra-sound -assisted alkaline hydrolysis.The extraction process of xylan was optimized by orthogonal experi-ment on the basis of single factor.The result indicated that the optimal parameters were as follows:the concentration of sodium hydroxide 7%,ratio of solid to liquid 1∶25,ultrasonic power 250 W,ultrasonic time 40 min,ultrasonic temperature 60 ℃.Under the optimized conditions,the yield of reducing sugar and total sugar in hydrolysate was 64.10 mg/g and 100.14 mg/g of raw corncobs,respectively.The yield of xylan was 9.01%.%以玉米芯为原料,经高温预处理后,采用超声波辅助碱法提取玉米芯木聚糖,在单因素实验的基础上,通过正交试验对玉米芯木聚糖提取工艺进行优化。结果表明:木聚糖的最佳制备工艺为氢氧化钠浓度7%,料液比1∶25,超声功率250 W,超声时间40 min,超声温度60℃。在此条件下,提取液中以玉米芯计还原糖的含量为64.10 mg/g,可溶性总糖含量为100.14 mg/g,木聚糖得率为9.01%。

  11. Climate warming feedback from mountain birch forest expansion: reduced albedo dominates carbon uptake.

    Science.gov (United States)

    de Wit, Heleen A; Bryn, Anders; Hofgaard, Annika; Karstensen, Jonas; Kvalevåg, Maria M; Peters, Glen P

    2014-07-01

    Expanding high-elevation and high-latitude forest has contrasting climate feedbacks through carbon sequestration (cooling) and reduced surface reflectance (warming), which are yet poorly quantified. Here, we present an empirically based projection of mountain birch forest expansion in south-central Norway under climate change and absence of land use. Climate effects of carbon sequestration and albedo change are compared using four emission metrics. Forest expansion was modeled for a projected 2.6 °C increase in summer temperature in 2100, with associated reduced snow cover. We find that the current (year 2000) forest line of the region is circa 100 m lower than its climatic potential due to land-use history. In the future scenarios, forest cover increased from 12% to 27% between 2000 and 2100, resulting in a 59% increase in biomass carbon storage and an albedo change from 0.46 to 0.30. Forest expansion in 2100 was behind its climatic potential, forest migration rates being the primary limiting factor. In 2100, the warming caused by lower albedo from expanding forest was 10 to 17 times stronger than the cooling effect from carbon sequestration for all emission metrics considered. Reduced snow cover further exacerbated the net warming feedback. The warming effect is considerably stronger than previously reported for boreal forest cover, because of the typically low biomass density in mountain forests and the large changes in albedo of snow-covered tundra areas. The positive climate feedback of high-latitude and high-elevation expanding forests with seasonal snow cover exceeds those of afforestation at lower elevation, and calls for further attention of both modelers and empiricists. The inclusion and upscaling of these climate feedbacks from mountain forests into global models is warranted to assess the potential global impacts.

  12. BVOC responses to realistic nitrogen fertilization and ozone exposure in silver birch.

    Science.gov (United States)

    Carriero, G; Brunetti, C; Fares, S; Hayes, F; Hoshika, Y; Mills, G; Tattini, M; Paoletti, E

    2016-06-01

    Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha(-1) yr(-1), applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area.

  13. Chapter 02: Basic wood biology—Anatomy for identification

    Science.gov (United States)

    Alex Wiedenhoeft

    2011-01-01

    Before the topics of using a hand lens, preparing wood for observation, and understanding the characters used in wood identification can be tackled, a general introduction to the biology of wood must be undertaken. The woods in commercial trade in Central America come almost exclusively from trees, so the discussion of wood biology is restricted to trees here, though...

  14. Surfactants of biological origin: The role of Mo(VI) and microwaves in the synthesis of xylan-based non-ionic surfactants.

    Science.gov (United States)

    Hricovíniová, Zuzana

    2016-06-25

    Microwave-assisted, phosphomolybdic acid (PMoA) catalyzed, glycosylation of unprotected d-xylose and d-lyxose, obtained after tandem Mo(VI)-catalyzed xylan hydrolysis-epimerization reaction, provides alkyl xylosides and lyxosides in short reaction times. A homologous series of amphiphilic alkyl pentosides varying in chain structure (C8-C14) was prepared in very good yields (38-73%). A new catalytic approach using the reusable heterogeneous PMoA/SiO2 catalyst provides benefits in terms of yields, environmental safety, operational simplicity, and thus opens new perspectives for the rational hemicellulose biomass utilization.

  15. 玉米芯木聚糖的提取及特性研究%Study on Extraction and Characterization of Xylan from Corn Cobs

    Institute of Scientific and Technical Information of China (English)

    金显春

    2011-01-01

    为了解玉米芯中水不溶性木聚糖在医药中的应用,采用搅拌下水浸24 h、1.5%次氯酸钠除杂、氢氧化钠碱提、乙酸中和、甲醇醇沉、甲醇及异丙醇醇洗多步法提取了玉米芯中水不溶性木聚糖.研究了所提水不溶性木聚糖的红外光谱及其粒径分布、堆积密度、振实密度、压缩指数、致密性、安息角、流变学等特性.结果表明,红外光谱可用来表征其形态结构.玉米芯中的水不溶性木聚糖密度低、凝聚流动性高,可以作为一种潜在的施药剂.%In order to evaluate xylan as a promise raw material for the pharmaceutical industry,the water-insoluble xylan samples were extracted from corn cobs following several steps:corn cobs was dipersed in water under stirring for 24 h, treated with 1.5% sodium hypochloride, extracted with sodium hydroxide, neutralized with acetic acid and settled down by methanol, washed with methanol and isopropanol. The obtained powder sample was analyzed by infrared spectroscopy. In addition, characterization regarding their particle size distribution, bulk and tap densities, compressibility index, compactability, repose angle and rheological data were also studied. The results demonstrated that infrared spectroscopy were shown to be able to evaluate the xylan structural conformation. Furthermore, xylan powder obtained from corn cobs was characterized as a material with low density and very cohesive flow properties and could be used as a promising polymer for drug delivery.

  16. Two-dimensional NMR evidence for cleavage of lignin and xylan substituents in wheat straw through hydrothermal pretreatment and enzymatic hydrolysis

    DEFF Research Database (Denmark)

    Yelle, Daniel J.; Kaparaju, Laxmi-Narasimha Prasad; Hunt, Christopher G.

    2013-01-01

    Solution-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy of plant cell walls is a powerful tool for characterizing changes in cell wall chemistry during the hydrothermal pretreatment process of wheat straw for second-generation bioethanol production. One-bond C-H NMR......-methyl-α-d-glucuronic acid of xylan. In the polysaccharide anomeric region, decreases in the minor β-d-mannopyranosyl, and α-l-arabinofuranosyl units were observed in the NMR spectra from hydrothermally pretreated wheat straw. The aromatic region indicated only minor changes to the aromatic structures during the process (e...

  17. Carbon sequestration via wood burial.

    Science.gov (United States)

    Zeng, Ning

    2008-01-03

    To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink.It is estimated that a sustainable long-term carbon sequestration potential for wood burial is 10 +/- 5 GtC y-1, and currently about 65 GtC is on the world's forest floors in the form of coarse woody debris suitable for burial. The potential is largest in tropical forests (4.2 GtC y-1), followed by temperate (3.7 GtC y-1) and boreal forests (2.1 GtC y-1). Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other concerns and factors will likely set a limit so that only part of the full potential can be realized.Based on data from North American logging industry, the cost for wood burial is estimated to be $14/tCO2($50/tC), lower than the typical cost for power plant CO2 capture with geological storage. The cost for carbon sequestration with wood burial is low because CO2 is removed from the atmosphere by the natural process of photosynthesis at little cost. The technique is low tech, distributed, easy to monitor, safe, and reversible, thus an attractive option for large-scale implementation in a world-wide carbon market.

  18. EVOLUTION OF LIGHTWEIGHT WOOD COMPOSITES

    Directory of Open Access Journals (Sweden)

    Marius C. BARBU

    2016-01-01

    Full Text Available Lightweight boards and beams in the wood-based construction and furniture industry are not a new topic. The density reduction of panels using sandwich structure with light cores was confirmed by users like doors or mobile homes more than three decades ago. Today many ways to attain a lighter wooden structure are on offer, partially in industrial application. The first one is the use of light-weight wood species like balsa, lime, pine from southern hemisphere plantations etc. limited by the availability, strength properties, gluability and so on. A second one is the sandwich structure made from hard faces like thick veneer, thin plywood, particleboard or high density thin fiberboard and cores made from honeycomb paper, very light wood species or foams like the polystyrene one. A third way to produce a light structure is to reduce the core drastically, using predesigned skeletons with special shapes and connections to the faces. The engines for these developments are on the one hand the fast growing market of knockdown furniture and on the other hand the increasing costs for energy and raw materials. Additional factors that make weight saving a primary economical objective for most producers are transportation costs, easier handling and higher acceptance among the end users. Moreover, customers demand more for ergonomical solutions regarding packaging. Many patents were generated by researchers and developers for new one-stage production processes for sandwich panels with wood- and impregnated paper-based facings made from veneers, particles or fibres and a core consisting of expandable foams, particles or embedded hard skeletons. These ideas or prototypes could be integrated in existing continuous pressing lines for wood based panels keeping some of the advantages of the continuous production technique in matters of efficiency. Some of the challenges of the light weight wooden structure are the connection in half or final parts, resistance to

  19. Carbon sequestration via wood burial

    Directory of Open Access Journals (Sweden)

    Zeng Ning

    2008-01-01

    Full Text Available Abstract To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a sustainable long-term carbon sequestration potential for wood burial is 10 ± 5 GtC y-1, and currently about 65 GtC is on the world's forest floors in the form of coarse woody debris suitable for burial. The potential is largest in tropical forests (4.2 GtC y-1, followed by temperate (3.7 GtC y-1 and boreal forests (2.1 GtC y-1. Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from North American logging industry, the cost for wood burial is estimated to be $14/tCO2($50/tC, lower than the typical cost for power plant CO2 capture with geological storage. The cost for carbon sequestration with wood burial is low because CO2 is removed from the atmosphere by the natural process of photosynthesis at little cost. The technique is low tech, distributed, easy to monitor, safe, and reversible, thus an attractive option for large-scale implementation in a world-wide carbon market.

  20. Effect of alkali concentration and temperature on extraction yield and quality of xylan from corn stover%碱浓度和温度对玉米秸秆木聚糖提取率和品质的影响

    Institute of Scientific and Technical Information of China (English)

    刘凯旋; 张傑; 李宏强; 徐建

    2016-01-01

    由于提取率和产品品质等方面的原因,作为玉米秸秆主要成分之一的木聚糖还未能得到充分有效的利用。为改善玉米秸秆木聚糖的提取率和品质,对影响木聚糖提取的碱浓度和温度2个关键因素进行了研究。使用组分分析和凝胶渗透色谱等手段对木聚糖得率、纯度和结构进行了研究,同时分离得到纤维素和醇溶木质素。结果表明,NaOH 浓度对木聚糖得率和结构的影响比温度显著,较优提取条件为:NaOH浓度为10%(w/v),提取温度90℃,此条件下木聚糖的溶出率和回收率分别为86.37%和76.92%,木聚糖纯度为63.90%。凝胶渗透色谱结果显示,碱浓度的增加使木聚糖的分子量降低,而随温度的升高则呈先升后降的趋势。此外,提取剩余物中纤维素的含量随碱浓度和温度强度的增加而增加。研究证明组合适当的碱浓度和提取温度可以在保证品质的前提下得到较高的木聚糖提取率。%Xylo-oligosaccharides derived from xylan have a high application potential in food and pharmaceutical industries. As an agricultural by-product, corn stover with high hemicellulose content is an important raw material for biorefinery. In order to broaden the raw material source of xylo-oligosaccharides, the work was carried out to investigate the effect of alkali extraction conditions on the quality of xylan. NaOH mass concentration and extraction temperature were selected to study their influence on yield, purity and structural characteristics of xylan. The de-waxed corn stover was treated with NaOH solution of 4, 6, 8, 10, 12, 16, 20 and 24wt% at 121℃ for 2 h with a constant solid-liquid ratio of 1:10 (g/mL). The extracts were neutralized to the pH value of 5.0 with the concentrated HCl, and then concentrated under vacuum. Xylan was precipitated from the filtrate by adding the ethanol with the volume of 3 times and then freeze-dried. The remained extracts were

  1. Use of nanofillers in wood coatings

    DEFF Research Database (Denmark)

    Nikolic, Miroslav; Lawther, John Mark; Sanadi, Anand Ramesh

    2015-01-01

    Wood has been used for thousands of years and remains an important material in the construction industry, most often protected with coatings. Development of nanotechnology allows further improvements or new performance properties to be achieved in wood coatings. Increased UV protection with nanom...... like a low level of loading, have already established nanoparticles in some areas of wood coatings. This article is a comprehensive scientific review of the published work in the use of nanofillers in wood coatings.......Wood has been used for thousands of years and remains an important material in the construction industry, most often protected with coatings. Development of nanotechnology allows further improvements or new performance properties to be achieved in wood coatings. Increased UV protection...

  2. Cold-atmospheric pressure plasma polymerization of acetylene on wood flour for improved wood plastics composites

    Science.gov (United States)

    Lekobou, William; Pedrow, Patrick; Englund, Karl; Laborie, Marie-Pierre

    2009-10-01

    Plastic composites have become a large class of construction material for exterior applications. One of the main disadvantages of wood plastic composites resides in the weak adhesion between the polar and hydrophilic surface of wood and the non-polar and hydrophobic polyolefin matrix, hindering the dispersion of the flour in the polymer matrix. To improve interfacial compatibility wood flour can be pretreated with environmentally friendly methods such as cold-atmospheric pressure plasma. The objective of this work is therefore to evaluate the potential of plasma polymerization of acetylene on wood flour to improve the compatibility with polyolefins. This presentation will describe the reactor design used to modify wood flour using acetylene plasma polymerization. The optimum conditions for plasma polymerization on wood particles will also be presented. Finally preliminary results on the wood flour surface properties and use in wood plastic composites will be discussed.

  3. Physicochemical patterns of ozone absorption by wood

    Science.gov (United States)

    Mamleeva, N. A.; Lunin, V. V.

    2016-11-01

    Results from studying aspen and pine wood ozonation are presented. The effect the concentration of ozone, the reagent residence time, and the content of water in a sample of wood has on ozone consumption rate and ozone demand are analyzed. The residence time is shown to determine the degree of ozone conversion degree and the depth of substrate destruction. The main patterns of ozone absorption by wood with different moisture content are found. Ways of optimizing the ozonation of plant biomass are outlined.

  4. Violates stem wood burning sustainable development?

    DEFF Research Database (Denmark)

    Czeskleba-Dupont, Rolf

    2008-01-01

    friendly effects of substituting wood burning for fossil fuels. With reference to Bent Sørensen's classical work on 'Renewable Energy' the assumption of CO2-neutrality regarding incineration is problematised when applied to plants with long rotation periods as trees. Registered CO2-emissions from wood...... burning are characterised together with particle and PAH emissions. The positive treatment of wood stove-technology in the Danish strategy for sustainable development (draft 2007) is critically evaluated and approaches to better regulation are identified....

  5. Wood colour related to kiln drying

    OpenAIRE

    Sundqvist, Bror

    2000-01-01

    Raised temperature in artificial drying has led to some changes of wood products such as colour and strength etc. For special treatment of wood-products with clearly modified properties, among them colour, is often high temperature and steam used industrially. Knowledge about the colour rendering from wood that is subjected to heat under humid conditions and/or artificial drying, especially kiln drying, is thus of interest. It is also of interest to understand the chemical background, for the...

  6. Three Perspectives on the Bretton Woods System

    OpenAIRE

    Eichengreen, Barry

    1992-01-01

    The twenty years that have passed since the collapse of the Bretton Woods System provide sufficient distance to safely assess the operation of the post-World War II international monetary system. This paper considers the history and historiography of Bretton Woods from three perspectives. First, I ask how the questions posed today about the operation of Bretton Woods differ from those asked twenty years ago. Second, I explore how today's answers to familiar questions differ from the answers o...

  7. Phylogeny of chitinases and its implications for estimating horizontal gene transfer from chitinase-transgenic silver birch (Betula pendula).

    Science.gov (United States)

    Lohtander, Katileena; Pasonen, Hanna-Leena; Aalto, Markku K; Palva, Tapio; Pappinen, Ari; Rikkinen, Jouko

    2008-01-01

    Chitinases are hydrolytic enzymes that have been employed in biotechnology in attempts to increase plants' resistance against fungal pathogens. Genetically modified plants have given rise to concerns of the spreading of transgenes into the environment through vertical or horizontal gene transfer (HGT). In this study, chitinase-like sequences from silver birch (Betula pendula) EST-libraries were identified and their phylogenetic relationships to other chitinases were studied. Phylogenetic analyses were used to estimate the frequency of historical gene transfer events of chitinase genes between plants and other organisms, and the usefulness of phylogenetic analyses as a source of information for the risk assessment of transgenic silver birch carrying a sugar beet chitinase IV gene was evaluated. Thirteen partial chitinase-like sequences, with an approximate length of 600 bp, were obtained from the EST-libraries. The sequences belonged to five chitinase classes. Some bacterial chitinases from Streptomyces and Burkholderia, as well as a chitinase from an oomycete, Phytophthora infestans, grouped together with the class IV chitinases of plants, supporting the hypothesis that some class IV chitinases in bacteria have evolved from eukaryotic chitinases via horizontal gene transfer. According to our analyses, HGT of a chitinase IV gene from eukaryotes to bacteria has presumably occurred only once. Based on this, the likelihood for the HGT of chitinase IV gene from transgenic birch to other organisms is extremely low. However, as risk is a function of both the likelihood and consequences of an event, the effects of rare HGT event(s) will finally determine the level of the risk.

  8. Perinatal maternal administration of Lactobacillus paracasei NCC 2461 prevents allergic inflammation in a mouse model of birch pollen allergy.

    Science.gov (United States)

    Schabussova, Irma; Hufnagl, Karin; Tang, Mimi L K; Hoflehner, Elisabeth; Wagner, Angelika; Loupal, Gerhard; Nutten, Sophie; Zuercher, Adrian; Mercenier, Annick; Wiedermann, Ursula

    2012-01-01

    The hygiene hypothesis implies that microbial agents including probiotic bacteria may modulate foetal/neonatal immune programming and hence offer effective strategies for primary allergy prevention; however their mechanisms of action are poorly understood. We investigated whether oral administration of Lactobacillus paracasei NCC 2461 to mothers during gestation/lactation can protect against airway inflammation in offspring in a mouse model of birch pollen allergy, and examined the immune mechanisms involved. BALB/c mice were treated daily with L. paracasei in drinking water or drinking water alone in the last week of gestation and during lactation. Their offspring were sensitized with recombinant Bet v 1, followed by aerosol challenge with birch pollen extract. Maternal exposure to L. paracasei prevented the development of airway inflammation in offspring, as demonstrated by attenuation of eosinophil influx in the lungs; reduction of IL-5 levels in bronchoalveolar lavage, and in lung and mediastinal lymph node cell cultures; and reduced peribronchial inflammatory infiltrate and mucus hypersecretion. While allergen-specific IgE and IgG antibody levels remained unchanged by the treatment, IL-4 and IL-5 production in spleen cell cultures were significantly reduced upon allergen stimulation in offspring of L. paracasei treated mice. Offspring of L. paracasei supplemented mothers had significantly reduced Bet v 1-specific as well as Concanavalin A-induced responses in spleen and mesenteric lymph node cell cultures, suggesting the modulation of both antigen-specific and mitogen-induced immune responses in offspring. These effects were associated with increased Foxp3 mRNA expression in the lungs and increased TGF-beta in serum. Our data show that in a mouse model of birch pollen allergy, perinatal administration of L. paracasei NCC 2461 to pregnant/lactating mothers protects against the development of airway inflammation in offspring by activating regulatory pathways

  9. Perinatal maternal administration of Lactobacillus paracasei NCC 2461 prevents allergic inflammation in a mouse model of birch pollen allergy.

    Directory of Open Access Journals (Sweden)

    Irma Schabussova

    Full Text Available BACKGROUND: The hygiene hypothesis implies that microbial agents including probiotic bacteria may modulate foetal/neonatal immune programming and hence offer effective strategies for primary allergy prevention; however their mechanisms of action are poorly understood. We investigated whether oral administration of Lactobacillus paracasei NCC 2461 to mothers during gestation/lactation can protect against airway inflammation in offspring in a mouse model of birch pollen allergy, and examined the immune mechanisms involved. METHODS: BALB/c mice were treated daily with L. paracasei in drinking water or drinking water alone in the last week of gestation and during lactation. Their offspring were sensitized with recombinant Bet v 1, followed by aerosol challenge with birch pollen extract. RESULTS: Maternal exposure to L. paracasei prevented the development of airway inflammation in offspring, as demonstrated by attenuation of eosinophil influx in the lungs; reduction of IL-5 levels in bronchoalveolar lavage, and in lung and mediastinal lymph node cell cultures; and reduced peribronchial inflammatory infiltrate and mucus hypersecretion. While allergen-specific IgE and IgG antibody levels remained unchanged by the treatment, IL-4 and IL-5 production in spleen cell cultures were significantly reduced upon allergen stimulation in offspring of L. paracasei treated mice. Offspring of L. paracasei supplemented mothers had significantly reduced Bet v 1-specific as well as Concanavalin A-induced responses in spleen and mesenteric lymph node cell cultures, suggesting the modulation of both antigen-specific and mitogen-induced immune responses in offspring. These effects were associated with increased Foxp3 mRNA expression in the lungs and increased TGF-beta in serum. CONCLUSION: Our data show that in a mouse model of birch pollen allergy, perinatal administration of L. paracasei NCC 2461 to pregnant/lactating mothers protects against the development of airway

  10. Impregnation of Natural Rubber into Rubber Wood: A Green Wood Composite

    OpenAIRE

    Wassa Ruayruay; Sureurg Khongtong

    2014-01-01

    A green wood composite material was developed from the two environmentally friendly substrates natural rubber (cis-1,4-polyisoprene) and rubber wood (Hevea brasiliensis). Natural rubber (NR) was introduced into rubber wood by pressurization of NR latex, followed by the removal of the aqueous phase to allow only dry NR to remain inside the wood structure. Scanning electron microscopy images and the weight increase of the dry impregnated samples revealed the retention of dry NR within the rubbe...

  11. Laboratory investigations of moisture conditions in wood frame walls with wood fiber insulation

    OpenAIRE

    Geving, Stig; Lunde, Erik; Holme, Jonas

    2015-01-01

    The purpose of this study was to investigate the moisture conditions in wood frame walls with wood fiber thermal insulation in a Nordic climate. Laboratory measurements were conducted on 15 different wall configurations. The test results showed that the wall configurations with wood fiber insulation performed rather similar as those with mineral wool, in regard to measured relative humidity at the external side of the insulation layer. The laboratory tests showed that wood fiber insu...

  12. The importance of mercury in leaves, bark and wood of eight tree species across four northeastern forests

    Science.gov (United States)

    Yanai, R. D.; Yang, Y.; Driscoll, C. T.; Montesdeoca, M.

    2016-12-01

    Mercury (Hg) deposition affects forests even in remote areas, but the amount of Hg in trees is not well known, in part because concentrations of Hg in wood are often below the analytical detection limit by ICP-OES. We analyzed Hg in wood, bark, and foliage of 8 tree species across four sites (Huntington Forest, NY; Sleepers River, VT; Hubbard Brook, NH; Bear Brook, ME) in the northeastern USA, using thermal decomposition, catalytic conversion, amalgamation, and atomic absorption spectrophotometry (USEPA Method 7473). The hardwood species, namely American beech (Fagus grandifolia Ehrh.), white ash (Fraxinus americana L.), yellow birch (Betula alleghaniensis Britt.), sugar maple (Acer saccharum Marshall.), and red maple (Acer rubrum L.), had lower Hg concentrations (averaging 7.7 ng g-1 in bark and 16.3 ng g-1 in foliage) than the conifers, namely red spruce (Picea rubens Sarg.), balsam fir (Abies balsamea (L.) Mill.) and white pine (Pinus strobus L.) (averaging 22.5 ng g-1 in bark and 28.6 ng g-1 in foliage) (p forest vegetation.

  13. Seven different genes encode a diverse mixture of isoforms of Bet v 1, the major birch pollen allergen

    Directory of Open Access Journals (Sweden)

    Gilissen Ludovicus JWJ

    2006-07-01

    Full Text Available Abstract Background Pollen of the European white birch (Betula pendula, syn. B. verrucosa is an important cause of hay fever. The main allergen is Bet v 1, member of the pathogenesis-related class 10 (PR-10 multigene family. To establish the number of PR-10/Bet v 1 genes and the isoform diversity within a single tree, PCR amplification, cloning and sequencing of PR-10 genes was performed on two diploid B. pendula cultivars and one interspecific tetraploid Betula hybrid. Sequences were attributed to putative genes based on sequence identity and intron length. Information on transcription was derived by comparison with homologous cDNA sequences available in GenBank/EMBL/DDJB. PCR-cloning of multigene families is accompanied by a high risk for the occurrence of PCR recombination artifacts. We screened for and excluded these artifacts, and also detected putative artifact sequences among database sequences. Results Forty-four different PR-10 sequences were recovered from B. pendula and assigned to thirteen putative genes. Sequence homology suggests that three genes were transcribed in somatic tissue and seven genes in pollen. The transcription of three other genes remains unknown. In total, fourteen different Bet v 1-type isoforms were identified in the three cultivars, of which nine isoforms were entirely new. Isoforms with high and low IgE-reactivity are encoded by different genes and one birch pollen grain has the genetic background to produce a mixture of isoforms with varying IgE-reactivity. Allergen diversity is even higher in the interspecific tetraploid hybrid, consistent with the presence of two genomes. Conclusion Isoforms of the major birch allergen Bet v 1 are encoded by multiple genes, and we propose to name them accordingly. The present characterization of the Bet v 1 genes provides a framework for the screening of specific Bet v 1 genes among other B. pendula cultivars or Betula species, and for future breeding for trees with a reduced

  14. Wood quality changes caused by mineral fertilization

    OpenAIRE

    Carlos Roberto Sette Jr; José Carlos de Deus Jr; Mario Tomazello Filho; Franciane Andrade de Pádua; Francine Neves Calil; Jean Paul Laclau

    2014-01-01

    The diverse and important use of wood from fast growth eucalyptus plantations requires the analysis of the effect of mineral fertilizers on wood quality. The objective of this study was to evaluate the anatomical characteristics and wood density from Eucalyptus grandis trees (3 m x 2 m spacing) fertilized with potassium and sodium (at planting, 6 th and 12th month). Fifteen (15) 6 years old eucalyptus trees were selected (5 trees/treatment), cut and wood samples at DBH (1,3 m) were taken for ...

  15. European wood-pastures in transition

    DEFF Research Database (Denmark)

    Wood-pastures are important elements of European cultural identity and have an exceptional ecological value, yet they are in decline all over Europe. The structure of wood-pastures is strongly influenced by grazing and multiple other land uses and by local and regional environmental conditions....... European Wood-Pastures in Transition examines the diverse expressions of wood-pastures across Europe. It provides a new perspective, using a social-ecological framework to explore social and ecological values, governing institutions, threats and conservation approaches. It explores the major drivers...

  16. Possibility of Extrusion of Wood Powders

    National Research Council Canada - National Science Library

    MIKI, Tsunehisa; TAKAKURA, Norio; IIZUKA, Takashi; YAMAGUCHI, Katsuhiko; KANAYAMA, Kouzou

    2003-01-01

    .... Effects of extrusion temperature, extrusion ratio, moisture content and particle size of the mixed wood powders on the flow characteristics, bending strength, hardness and bulk density of extruded...

  17. Wood energy 2000; Bois energie 2000

    Energy Technology Data Exchange (ETDEWEB)

    Druette, L. [Centre Scientifique et Technique du Batiment, (CSTB), 44 - Nantes (France); Lacome, T. [AFNOR, 75 - Paris (France); Roy, C. [Agence de l' Environnement et de la Maitrise de l' Energie, ADEME, 75 - Paris (France)] [and others

    2000-07-01

    The deregulation of the Electric Market and the opening of the Green Certificate exchange market force the set up of renewable energies. The wood, which is for most of european countries an important part of renewable fuel, should see the increase of its utilization. This conference on the wood energy deals the main aspects of this energy development. The papers present the wood burning furnaces technology assessment, the wood fuel market and the standardization of the appliances in this domain. Some papers also include the consequences of the big storms of december 1999. (A.L.B.)

  18. Moisture Performance of wood-plastic composites reinforced with extracted and delignified wood flour

    Science.gov (United States)

    Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

    2014-01-01

    This study investigated the effect of using extracted and delignified wood flour on water sorption properties of wood–plastic composites. Wood flour (WF) extraction was performed with three solvent systems: toluene/ethanol (TE), acetone/water (AW), and hot water (HW); delignification was conducted using sodium chlorite/acetic acid solution. A 24 full-factorial...

  19. Detection of wood failure by image processing method: influence of algorithm, adhesive and wood species

    Science.gov (United States)

    Lanying Lin; Sheng He; Feng Fu; Xiping Wang

    2015-01-01

    Wood failure percentage (WFP) is an important index for evaluating the bond strength of plywood. Currently, the method used for detecting WFP is visual inspection, which lacks efficiency. In order to improve it, image processing methods are applied to wood failure detection. The present study used thresholding and K-means clustering algorithms in wood failure detection...

  20. Effect of different wood pretreatments on the sorption-desorption of linuron and metalaxyl by woods.

    Science.gov (United States)

    Rodríguez-Cruz, M Sonia; Andrades, M Soledad; Parada, A María; Sánchez-Martín, M Jesús

    2008-08-27

    The sorption-desorption of two different pesticides, linuron and metalaxyl, by woods was studied. Sorbent/solution ratio and sorption kinetics were also determined. Untreated wood and water, NaOH, HCl, and octadecyltrimethylammonium bromide (ODTMA) treated pine (softwood) and oak (hardwood) were used as sorbents. Linuron and metalaxyl were sorbed by untreated woods up to 80 and 40%, respectively, in a short time when the sorbent/solution ratio of 1:10 was used. Sorption of pesticides was significantly higher by pine, having higher lignin content, than by oak. Freundlich sorption constants (K(f)) were 96.2 and 74.4 (linuron) and 8.28 and 4.95 (metalaxyl) for untreated pine and oak woods and increased 1.04-2.35-fold (linuron) and 1.33-2.17-fold (metalaxyl) when woods were treated. The sorption was higher by HCl- and ODTMA-treated woods. Additionally, Freundlich desorption constants also indicated greater sorption irreversibility of both pesticides for treated woods than for untreated woods. The results revealed wood residues as a promising, low-cost, and environmentally friendly material to immobilize pesticides in soils, preventing water contamination. Wood treatments aimed at removing soluble wood extracts or at modifying wood chemical structure could increase their sorption capacity.