Objective: To investigate the toxicity of aqueous extract of Guibourtia tessmannii(Harms) J. Leonard(G. tessmannii) and evaluate its safety.Methods: NMRI mice were used to determine the acute toxicity of G. tessmannii...Objective: To investigate the toxicity of aqueous extract of Guibourtia tessmannii(Harms) J. Leonard(G. tessmannii) and evaluate its safety.Methods: NMRI mice were used to determine the acute toxicity of G. tessmannii.Increasing concentrations of the plant extracts were administered intraperitoneally or by force-feeding. General behavior and death were monitored and recorded daily for 7 days.In order to determine the sub-acute toxicity of the extract, several doses were administered by oral gavage daily for 28 days in adult Wistar rats. Different parameters were assessed including body weight, food and water intake, biochemical parameters and several vital organ weights.Results: LD50 of 328.78 mg/kg was obtained by i.p. route and more than 5 000 mg/kg was obtained in acute toxicity by oral route. In sub-acute toxicity, no significant alteration was observed in body weight or vital organs, food and water intake, and biochemical parameters.Conclusions: The results showed that the aqueous extract of G. tessmannii has low toxicity intraperitoneally and no sub-acute toxicity via oral intake.展开更多
Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sa...Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties.展开更多
The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species（P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis） grown in Indonesia were investigated...The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species（P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis） grown in Indonesia were investigated by GC and GC–MS.Generally,the amounts of extractive contents were higher in the inner bark than in the outer bark except for P.merksuii.Fatty acids,monoterpenes,sesquiterpenes,resin acids,triterpenoids,and steroids were detected and quantified.Inner and outer barks differed not only in content of these compounds but also in their composition.Fatty acids and alcohols were the major classes of lipophilic compounds in the outer bark of P.caribeae, P.insularis,and P.montezumae.Steroids and triterpenoids were the dominant compounds identified in the inner bark of P.elliotii,P.insularis,and P.merkusii.Resin acids were the most abundant group in the inner bark of P.oocarpa whereas monoterpenes and sesquiterpenes were recorded in minor quantities in both bark layers of all species.展开更多
Using 57 Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, Ch...Using 57 Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, China. All bark samples showed two overlapping doublets with large and small quadruple splitting. Only Platycladus orientalis's barks exhibited one sextet. Based on Mssbauer parameters, they were attributed to paramagnetic ferrous, paramagnetic ferric and magnetic iron, respectively. For the sampling site which is about 6 kilometers from Lanzhou Steel Factory, the ratio of ferrous to ferric was higher in the sample of Platanus acerifolia's barks, whereas the barks of Platycladus orientalis and Cedrus deodara gave similar values of this ratio. Platycladus orientalis was the most effective in accumulating iron complexes in barks among the three trees. Platanus acerifolia's barks sampled at Lanzhou Steel Factory's area exhibited higher absolute intensities of iron components and lower ration of ferrous to ferric, indicating that industrial air pollution is a contributing factor in accumulating iron compounds in the tree barks of this region.展开更多
Activity 1 Think about the following questions and write down your answers before reading the text.1.What are some common factors that usually cause damage to trees when they are struck by lightning?2.How might the un...Activity 1 Think about the following questions and write down your answers before reading the text.1.What are some common factors that usually cause damage to trees when they are struck by lightning?2.How might the unique characteristics of a tree contribute to its ability to survive a lightning strike?展开更多
Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberini...Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberinic acids(SA)from outer birch bark,many industries,such as plywood and pulp,often choose to incinerate substan-tial amounts of leftover birch bark to meet their energy needs.This highlights the importance of obtaining valu-able products from wood.The objective of this study was to examine various fractions of SA and assess their potential for wood impregnation.The fractions included SA potassium salts in ethanol(SAK-EtOH)and water(SAK-H2O),SA suspension in water(SAS-H2O)and dried SA,which was subsequently diluted in ethanol(DSA-EtOH).There is significant potential for utilizing SA in wood treatment formulations as a sustainable alternative to harmful petroleum-derived chemicals.This approach not only addresses environmental concerns but also enhances the functionality of wood in construction applications,such as improving impregnation for moisture and fungal protection.Among the solutions tested,the ethanol solution of SA,specifically DSA-EtOH,showed the highest weight percent gain(WPG)and the greatest leaching resistance.GPC analysis showed that SA salts in ethanol(SAK-EtOH)and water(SAK-H2O)predominantly consist of low molecular fractions and each process(acidification and drying)reduces the low molecular content in the sample.This suggests that SA polymerizes after drying,making it necessary to dissolve it in ethanol to meet the requirements for impregnation.Further opti-mization,including adjustments in the concentration of the SA ethanol solution and the curing temperature,is essential to identify the optimal conditions for more in-depth impregnation studies.展开更多
BACKGROUND Recently,the identification of cell apoptosis induced by natural products has become research hotspot and frontier in the biopharmaceutical and food industries under the umbrella of global green development...BACKGROUND Recently,the identification of cell apoptosis induced by natural products has become research hotspot and frontier in the biopharmaceutical and food industries under the umbrella of global green development worldwide.Traditionally,cell apoptosis is identified using morphological,biochemical,and cell cycle experiments,which is time consuming,and experimental materials are not from the same group,and it is very hard to ensure the identity and veracity of results of former and latter experiments.AIM To establish a selective,instant,and practical protocol to identify cell apoptosis induced by natural products.METHODS A one transient cell processing procedure(OTCPP)was used to detect human colorectal cancer LoVo cell apoptosis after treatment with Pinus massoniana bark extract(PMBE)at the morphological,biochemical,and cell cycle levels.The methods used included treatment with DNA gel electrophoresis,fluorescence microscopy,and flow cytometry.RESULTS In PMBE-treated LoVo cells,we observed a DNA ladder on gel electrophoresis and fluorescence microscopy revealed"nuclear shrinkage,chromatin condensation or fragmentation".In addition,flow cytometry showed an"obvious apoptosis curve".Thus OTCPP achieved synchronous detection of the morphology,biochemistry,cell cycle,and the DNA content of the cells.CONCLUSION OTCPP can quickly identify apoptosis and measure the apoptosis rate,thereby unifying qualitative and quantitative analysis.展开更多
Turmoil caused by major refinancing plans of listed companies in the mainland stock market leads regulators to vow stricter approval processes On March 5,shareholders of Ping An Insurance(Group)Co.of China Ltd. (Ping ...Turmoil caused by major refinancing plans of listed companies in the mainland stock market leads regulators to vow stricter approval processes On March 5,shareholders of Ping An Insurance(Group)Co.of China Ltd. (Ping An)passed a refinancing plan of 120 billion yuan(＄17 billion)at its first interim meeting of the year with an overwhelming 92 percent in favor.展开更多
Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in ...Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands.The research was carried out in the Babiog orski National Park.The research plots were marked out in the gaps of the stands,which were formed as a result of bark beetle gradation.Control plots were located in undisturbed stands.The research covered wood of two species–spruce and beech in the form of cubes with dimensions of 50 mm×50 mm×22 mm.Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months.A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found.Wood characteristics strongly correlated with soil moisture.A significantly higher mass decline of wood samples was recorded on the reference study plots,which were characterized by more stable moisture conditions.Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture.The wood species covered by the study differed in the decomposition rate.Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples.Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.展开更多
Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this w...Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.展开更多
Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid cha...Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).展开更多
Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particle...Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.展开更多
Birch outer bark(BOB)from Betula pendula Roth.is a unique and valuable biomass feedstock that contains suberin.The biopolyester suberin is built from bifunctional fatty acids-suberinic acids(SA)-which can be obtained ...Birch outer bark(BOB)from Betula pendula Roth.is a unique and valuable biomass feedstock that contains suberin.The biopolyester suberin is built from bifunctional fatty acids-suberinic acids(SA)-which can be obtained through a depolymerization process in an alkaline medium and used as a binder due to their adhesive properties.The aim of this study was to develop the SA-containing binder and identify suitable pressing conditions to produce plywood that meets the shear strength requirements of the EN 314-2 standard 3rd moisture resistance class for bonding quality,ensuring durability in unprotected exterior conditions(shear strength≥1 N/mm^(2)).The raw BOB material was modified by extraction,milling,and fractionation,and the depolymerization methodology was enhanced by additional sieving to improve the adhesive properties of the obtained binders.Several analytical methods were used to characterize the feedstock and the binders.Higher heating value was used to assess the pure outer bark content of BOB.GC-MS and GPC were used to describe the monomeric and oligomeric composition of binders.TGA was used to describe the biopolymeric composition and DSC was used to determine the thermal behavior of the binders.As a result,successful modification of feedstock(extracted BOB,milled through 2 mm sieve,1-2 mm fraction used)and its depolymerization process(implementing the separation of coarse ligno-carbohydrate particles by 1 mm mesh sieve)was employed to obtain a binder for which suitable hot-pressing parameters were determined−200℃for 5 min at 1.8 MPa.Consequently,plywood with shear strength of 1.26±0.18 N/mm^(2),which adheres to the EN 314-2 standards 3rd moisture resistance class,was obtained.展开更多
The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and l...The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and lowtoxic base-catalyzed modification with propylene carbonate(PC).FTIR spectroscopy,HP-LC,GC,GPC,and wet chemistry methods were used to characterize the starting constituents,intermediate and final products of the reaction and to monitor the different pathways of PC conversion.The reaction of extractives as well as the model compounds,including catechol,xylose,PEG 400,and benzoic acid,with PC indicated the ability of OH groups of different origins present in the extractives to condense with equivalent amounts of PC.The polyols obtained consist of a copolymer fraction with one oxypropyl unit grafted per OH functionality of extractive components on average and oligo oxypropyl diols with a small number of carbonate linkages in the chain,obtained as a result of remaining PC homopolymerization.The domination of the oxypropylation mechanism vs.transcarbonation for PC ring opening was observed for both copolymerization and homopolymerization processes,making the process of oxypropylation with PC similar to that of conventional oxypropylation.At optimal reaction conditions,including a PC/OH ratio of 3.0 and a 24-h duration at 150°C,uniform polyols with low viscosity of~900 mPa·s^(-1),a biomass content of~27%,and an OHV of~500 mg KOH·g^(-1) were obtained.Increasing the temperature of modification allows shortening the process but drastically increases the polyol viscosity.At fixed temperature values,increasing the PC/OH ratio not only decreases the biomass content but also strongly prolongs the processing.The significantly increased duration of the process using PC as an alternative oxyalkylation agent compared to that of oxyalkylation with propylene oxide is a reasonable trade-off for using a safer and more environmentally friendly technology.展开更多
Natural disturbances have significantly intensified across European forests,with bark beetle outbreaks being the most rapidly escalating disturbance type.Since 2018,the Czech Republic(Central Europe)has become a Europ...Natural disturbances have significantly intensified across European forests,with bark beetle outbreaks being the most rapidly escalating disturbance type.Since 2018,the Czech Republic(Central Europe)has become a Europe's disturbance epicentre due to the unprecedented outbreak of spruce bark beetle Ips typographus in the forests dominated by Norway spruce Picea abies.Here we provide novel insights into the impacts and dynamics of this disturbance from 2016 to 2022.The investigation is based on annual forest change maps developed by the classification of optical and Synthetic Aperture Radar satellite imagery.We identified seven major outbreak foci across the country,where the outbreaks culminated between 2018 and 2021.Most of the outbreak waves exhibited a symmetric shape,characterized by a three-year build-up phase,a single culmination year,and the subsequent decline.The substantial proportion of spruce remaining in the outbreak areas after the culmination point implies that resource depletion is an improbable cause for the outbreak's retreat.In the year of retreat,the proportion of spruce in the forest ranged between 26%and 36%in most of the outbreak areas.The disturbance dynamics manifested a transition from the emergence of new tree mortality spots in the early outbreak phase to their short-range expansion,suggesting density-dependent changes in bark beetle dispersal during the studied period.The core disturbance zone,pinpointed in 2022,covered an area of 9,000 km^(2) and experienced a 38%loss in forest cover.Within this area,forest fragmentation increased significantly,leading to a greater forest patch complexity and reduced connectivity among the patches.The presented findings can serve as a glimpse into the future for other European regions,revealing the potential impacts of natural disturbances amplified by climate change.展开更多
基金Supported by the doctoral training funds no.84722652USTM/4802 AC-USTM,of the University of Sciences and Technique of Masuku
文摘Objective: To investigate the toxicity of aqueous extract of Guibourtia tessmannii(Harms) J. Leonard(G. tessmannii) and evaluate its safety.Methods: NMRI mice were used to determine the acute toxicity of G. tessmannii.Increasing concentrations of the plant extracts were administered intraperitoneally or by force-feeding. General behavior and death were monitored and recorded daily for 7 days.In order to determine the sub-acute toxicity of the extract, several doses were administered by oral gavage daily for 28 days in adult Wistar rats. Different parameters were assessed including body weight, food and water intake, biochemical parameters and several vital organ weights.Results: LD50 of 328.78 mg/kg was obtained by i.p. route and more than 5 000 mg/kg was obtained in acute toxicity by oral route. In sub-acute toxicity, no significant alteration was observed in body weight or vital organs, food and water intake, and biochemical parameters.Conclusions: The results showed that the aqueous extract of G. tessmannii has low toxicity intraperitoneally and no sub-acute toxicity via oral intake.
文摘Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties.
基金supported by JASSO(Japan Student Services Organization)DPP Grant 2016(Faculty of Forestry,UGM)
文摘The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species（P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis） grown in Indonesia were investigated by GC and GC–MS.Generally,the amounts of extractive contents were higher in the inner bark than in the outer bark except for P.merksuii.Fatty acids,monoterpenes,sesquiterpenes,resin acids,triterpenoids,and steroids were detected and quantified.Inner and outer barks differed not only in content of these compounds but also in their composition.Fatty acids and alcohols were the major classes of lipophilic compounds in the outer bark of P.caribeae, P.insularis,and P.montezumae.Steroids and triterpenoids were the dominant compounds identified in the inner bark of P.elliotii,P.insularis,and P.merkusii.Resin acids were the most abundant group in the inner bark of P.oocarpa whereas monoterpenes and sesquiterpenes were recorded in minor quantities in both bark layers of all species.
文摘Using 57 Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, China. All bark samples showed two overlapping doublets with large and small quadruple splitting. Only Platycladus orientalis's barks exhibited one sextet. Based on Mssbauer parameters, they were attributed to paramagnetic ferrous, paramagnetic ferric and magnetic iron, respectively. For the sampling site which is about 6 kilometers from Lanzhou Steel Factory, the ratio of ferrous to ferric was higher in the sample of Platanus acerifolia's barks, whereas the barks of Platycladus orientalis and Cedrus deodara gave similar values of this ratio. Platycladus orientalis was the most effective in accumulating iron complexes in barks among the three trees. Platanus acerifolia's barks sampled at Lanzhou Steel Factory's area exhibited higher absolute intensities of iron components and lower ration of ferrous to ferric, indicating that industrial air pollution is a contributing factor in accumulating iron compounds in the tree barks of this region.
文摘Activity 1 Think about the following questions and write down your answers before reading the text.1.What are some common factors that usually cause damage to trees when they are struck by lightning?2.How might the unique characteristics of a tree contribute to its ability to survive a lightning strike?
基金supported according to contract No.5.1.1.2.i.0/1/22/A/CFLA/007 between“Forest Sector Competence Centre of Latvia”Ltd.the Central Finance and Contracting Agency which dated 20th January of 2023.
文摘Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberinic acids(SA)from outer birch bark,many industries,such as plywood and pulp,often choose to incinerate substan-tial amounts of leftover birch bark to meet their energy needs.This highlights the importance of obtaining valu-able products from wood.The objective of this study was to examine various fractions of SA and assess their potential for wood impregnation.The fractions included SA potassium salts in ethanol(SAK-EtOH)and water(SAK-H2O),SA suspension in water(SAS-H2O)and dried SA,which was subsequently diluted in ethanol(DSA-EtOH).There is significant potential for utilizing SA in wood treatment formulations as a sustainable alternative to harmful petroleum-derived chemicals.This approach not only addresses environmental concerns but also enhances the functionality of wood in construction applications,such as improving impregnation for moisture and fungal protection.Among the solutions tested,the ethanol solution of SA,specifically DSA-EtOH,showed the highest weight percent gain(WPG)and the greatest leaching resistance.GPC analysis showed that SA salts in ethanol(SAK-EtOH)and water(SAK-H2O)predominantly consist of low molecular fractions and each process(acidification and drying)reduces the low molecular content in the sample.This suggests that SA polymerizes after drying,making it necessary to dissolve it in ethanol to meet the requirements for impregnation.Further opti-mization,including adjustments in the concentration of the SA ethanol solution and the curing temperature,is essential to identify the optimal conditions for more in-depth impregnation studies.
基金Supported by 2023 Key R&D Projects of Tongji University,No.150029607160-24323Industrial Key Program Foundation of Guangdong Province:R&D of Natural Novel Anticancer Drugs,No.2004B10401033。
文摘BACKGROUND Recently,the identification of cell apoptosis induced by natural products has become research hotspot and frontier in the biopharmaceutical and food industries under the umbrella of global green development worldwide.Traditionally,cell apoptosis is identified using morphological,biochemical,and cell cycle experiments,which is time consuming,and experimental materials are not from the same group,and it is very hard to ensure the identity and veracity of results of former and latter experiments.AIM To establish a selective,instant,and practical protocol to identify cell apoptosis induced by natural products.METHODS A one transient cell processing procedure(OTCPP)was used to detect human colorectal cancer LoVo cell apoptosis after treatment with Pinus massoniana bark extract(PMBE)at the morphological,biochemical,and cell cycle levels.The methods used included treatment with DNA gel electrophoresis,fluorescence microscopy,and flow cytometry.RESULTS In PMBE-treated LoVo cells,we observed a DNA ladder on gel electrophoresis and fluorescence microscopy revealed"nuclear shrinkage,chromatin condensation or fragmentation".In addition,flow cytometry showed an"obvious apoptosis curve".Thus OTCPP achieved synchronous detection of the morphology,biochemistry,cell cycle,and the DNA content of the cells.CONCLUSION OTCPP can quickly identify apoptosis and measure the apoptosis rate,thereby unifying qualitative and quantitative analysis.
文摘Turmoil caused by major refinancing plans of listed companies in the mainland stock market leads regulators to vow stricter approval processes On March 5,shareholders of Ping An Insurance(Group)Co.of China Ltd. (Ping An)passed a refinancing plan of 120 billion yuan(＄17 billion)at its first interim meeting of the year with an overwhelming 92 percent in favor.
基金financed by the National Science Centre,Poland:decision no.DEC 2020/39/B/NZ9/00372 and decision no.DEC-2021/43/O/NZ9/00066。
文摘Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands.The research was carried out in the Babiog orski National Park.The research plots were marked out in the gaps of the stands,which were formed as a result of bark beetle gradation.Control plots were located in undisturbed stands.The research covered wood of two species–spruce and beech in the form of cubes with dimensions of 50 mm×50 mm×22 mm.Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months.A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found.Wood characteristics strongly correlated with soil moisture.A significantly higher mass decline of wood samples was recorded on the reference study plots,which were characterized by more stable moisture conditions.Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture.The wood species covered by the study differed in the decomposition rate.Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples.Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.
基金supported by the Institut de la Francophonie pour le Developpement Durable(IFDD/Canada)/Projet de Deploiement des Technologies et Innovations Environnementales(PDTIE)funded by Organisation Internationale de la Francophonie(OIF)the Organisation of African,Caribbean and Pacific States and the European Union(EU)(FED/220/421-370)the Local Materials Promotion Authority(MIPROMALO)of the Ministry of Scientific Research and Innovation of Cameroon who made it possible for this scientific work to be carried out.
文摘Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.
文摘Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).
基金the financial support provided by UMS Great(GUG0217-1/2018),which played a crucial role in the completion of this study.
文摘Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.
基金supported according to contract No.5.1.1.2.i.0/1/22/A/CFLA/007 between“Forest Sector Competence Centre of Latvia”Ltd.,and the Central Finance and Contracting Agency which dated 20th January of 2023.
文摘Birch outer bark(BOB)from Betula pendula Roth.is a unique and valuable biomass feedstock that contains suberin.The biopolyester suberin is built from bifunctional fatty acids-suberinic acids(SA)-which can be obtained through a depolymerization process in an alkaline medium and used as a binder due to their adhesive properties.The aim of this study was to develop the SA-containing binder and identify suitable pressing conditions to produce plywood that meets the shear strength requirements of the EN 314-2 standard 3rd moisture resistance class for bonding quality,ensuring durability in unprotected exterior conditions(shear strength≥1 N/mm^(2)).The raw BOB material was modified by extraction,milling,and fractionation,and the depolymerization methodology was enhanced by additional sieving to improve the adhesive properties of the obtained binders.Several analytical methods were used to characterize the feedstock and the binders.Higher heating value was used to assess the pure outer bark content of BOB.GC-MS and GPC were used to describe the monomeric and oligomeric composition of binders.TGA was used to describe the biopolymeric composition and DSC was used to determine the thermal behavior of the binders.As a result,successful modification of feedstock(extracted BOB,milled through 2 mm sieve,1-2 mm fraction used)and its depolymerization process(implementing the separation of coarse ligno-carbohydrate particles by 1 mm mesh sieve)was employed to obtain a binder for which suitable hot-pressing parameters were determined−200℃for 5 min at 1.8 MPa.Consequently,plywood with shear strength of 1.26±0.18 N/mm^(2),which adheres to the EN 314-2 standards 3rd moisture resistance class,was obtained.
基金financial support from the Latvian Council of Science,Project No.lzp-2021/1-0207.
文摘The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and lowtoxic base-catalyzed modification with propylene carbonate(PC).FTIR spectroscopy,HP-LC,GC,GPC,and wet chemistry methods were used to characterize the starting constituents,intermediate and final products of the reaction and to monitor the different pathways of PC conversion.The reaction of extractives as well as the model compounds,including catechol,xylose,PEG 400,and benzoic acid,with PC indicated the ability of OH groups of different origins present in the extractives to condense with equivalent amounts of PC.The polyols obtained consist of a copolymer fraction with one oxypropyl unit grafted per OH functionality of extractive components on average and oligo oxypropyl diols with a small number of carbonate linkages in the chain,obtained as a result of remaining PC homopolymerization.The domination of the oxypropylation mechanism vs.transcarbonation for PC ring opening was observed for both copolymerization and homopolymerization processes,making the process of oxypropylation with PC similar to that of conventional oxypropylation.At optimal reaction conditions,including a PC/OH ratio of 3.0 and a 24-h duration at 150°C,uniform polyols with low viscosity of~900 mPa·s^(-1),a biomass content of~27%,and an OHV of~500 mg KOH·g^(-1) were obtained.Increasing the temperature of modification allows shortening the process but drastically increases the polyol viscosity.At fixed temperature values,increasing the PC/OH ratio not only decreases the biomass content but also strongly prolongs the processing.The significantly increased duration of the process using PC as an alternative oxyalkylation agent compared to that of oxyalkylation with propylene oxide is a reasonable trade-off for using a safer and more environmentally friendly technology.
基金supported by the project“EVA4.0”,No.CZ.02.1.01/0.0/0.0/16_019/0000803 financed by OP RDE of the Czech Republicthe project of the National Agency for Agriculture Research of the Czech Republic No.QK23020039lthe Technology Agency of the Czech Republic under grant No.SS02030018.
文摘Natural disturbances have significantly intensified across European forests,with bark beetle outbreaks being the most rapidly escalating disturbance type.Since 2018,the Czech Republic(Central Europe)has become a Europe's disturbance epicentre due to the unprecedented outbreak of spruce bark beetle Ips typographus in the forests dominated by Norway spruce Picea abies.Here we provide novel insights into the impacts and dynamics of this disturbance from 2016 to 2022.The investigation is based on annual forest change maps developed by the classification of optical and Synthetic Aperture Radar satellite imagery.We identified seven major outbreak foci across the country,where the outbreaks culminated between 2018 and 2021.Most of the outbreak waves exhibited a symmetric shape,characterized by a three-year build-up phase,a single culmination year,and the subsequent decline.The substantial proportion of spruce remaining in the outbreak areas after the culmination point implies that resource depletion is an improbable cause for the outbreak's retreat.In the year of retreat,the proportion of spruce in the forest ranged between 26%and 36%in most of the outbreak areas.The disturbance dynamics manifested a transition from the emergence of new tree mortality spots in the early outbreak phase to their short-range expansion,suggesting density-dependent changes in bark beetle dispersal during the studied period.The core disturbance zone,pinpointed in 2022,covered an area of 9,000 km^(2) and experienced a 38%loss in forest cover.Within this area,forest fragmentation increased significantly,leading to a greater forest patch complexity and reduced connectivity among the patches.The presented findings can serve as a glimpse into the future for other European regions,revealing the potential impacts of natural disturbances amplified by climate change.
