Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.305
Filtrar
1.
Nat Commun ; 11(1): 4692, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943624

RESUMO

Hemicelluloses, a family of heterogeneous polysaccharides with complex molecular structures, constitute a fundamental component of lignocellulosic biomass. However, the contribution of each hemicellulose type to the mechanical properties of secondary plant cell walls remains elusive. Here we homogeneously incorporate different combinations of extracted and purified hemicelluloses (xylans and glucomannans) from softwood and hardwood species into self-assembled networks during cellulose biosynthesis in a bacterial model, without altering the morphology and the crystallinity of the cellulose bundles. These composite hydrogels can be therefore envisioned as models of secondary plant cell walls prior to lignification. The incorporated hemicelluloses exhibit both a rigid phase having close interactions with cellulose, together with a flexible phase contributing to the multiscale architecture of the bacterial cellulose hydrogels. The wood hemicelluloses exhibit distinct biomechanical contributions, with glucomannans increasing the elastic modulus in compression, and xylans contributing to a dramatic increase of the elongation at break under tension. These diverging effects cannot be explained solely from the nature of their direct interactions with cellulose, but can be related to the distinct molecular structure of wood xylans and mannans, the multiphase architecture of the hydrogels and the aggregative effects amongst hemicellulose-coated fibrils. Our study contributes to understanding the specific roles of wood xylans and glucomannans in the biomechanical integrity of secondary cell walls in tension and compression and has significance for the development of lignocellulosic materials with controlled assembly and tailored mechanical properties.


Assuntos
Parede Celular/química , Celulose/química , Extratos Vegetais/química , Plantas/química , Polissacarídeos/química , Madeira/química , Configuração de Carboidratos , Sequência de Carboidratos , Catárticos/química , Citoesqueleto/química , Hidrogéis/química , Mananas , Xilanos/química
2.
PLoS One ; 15(8): e0236406, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745098

RESUMO

To address concerns over plastics in the global environment, this project produced three wood plastics composites (WPCs) which could divert plastics from the waste stream into new materials. The three materials made had a ratio of 85%:15%, 90%:10%, and 95%:5% low density polyethylene (LDPE) to wood powder and were produced using the dissolution method. Physical and mechanical properties of each WPC were evaluated according to Japanese Industrial Standard (JIS) A 5908:2003. Their degradation in nature was evaluated through a graveyard test and assay test conducted in Coptotermes curvignathus termites. Results showed that density, moisture content, thickness swelling and water absorption of the WPCs fulfilled the JIS standard. The mechanical properties of these composites also met the JIS standard, particularly their modulus of elasticity (MOE). Modulus of rupture (MOR) and internal bonding (IB) showed in lower values, depending on the proportion of wood filler they contained. Discoloration of the WPCs was observed after burial in the soil with spectra alteration of attenuated transmission reflectance (ATR) in the band of 500-1000 cm-1 which could be assigned to detach the interphase between wood and plastics. As termite bait, the WPCs decreased in weight, even though the mass loss was comparatively small. Micro Confocal Raman Imaging Spectrometer revealed that termite guts from insects feeding on WPCs contained small amounts of LDPE. This indicated termite can consume plastics in the form of WPCs. Thus WPCs made predominantly of plastics can be degraded in nature. While producing WPCs can assist in decreasing plastics litter in the environment, the eventual fate of the LDPE in termites is still unknown.


Assuntos
Plásticos Biodegradáveis/química , Elasticidade , Polietileno/química , Madeira/química , Plásticos Biodegradáveis/síntese química , Humanos , Polietileno/síntese química , Reciclagem , Água/química
3.
Ecotoxicol Environ Saf ; 204: 111117, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32798753

RESUMO

Wood distillate (pyroligneous acid) can be successfully applied in agriculture to increase crop quality and productivity with a lower risk for the environment respect to synthetic chemical herbicides, pesticides or fertilizers. However, the effects of wood distillate on the environment and biota are still under investigation, depending on biological attributes of potentially influenced organisms. The potential toxicological effects of wood distillate on sensitive non-target organisms, lichens and mosses, are studied for the first time. The physiological parameters (chlorophyll a fluorescence emission FV/FM and PI(ABS), chlorophyll content, spectral reflectance, antioxidant power, and dehydrogenase activity) and eventual bioaccumulation of selected elements (As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, Zn) were investigated in the lichen Xanthoria parietina and the moss Hypnum cupressiforme after short-term treatments over a range of wood distillate solutions (1:300, 1:500, 1:700) to detect potential early stress responses. Overall, the lichen did not show changes after the treatments, while in the moss wood distillate caused only modest alterations in FV/FM and PI(ABS) and progressive increasing of antioxidant activity according to the dose supplied. The bioaccumulation of toxic elements was low and did not show any pattern of uptake with increasing concentrations of wood distillate.


Assuntos
Briófitas/efeitos dos fármacos , Herbicidas/toxicidade , Líquens/efeitos dos fármacos , Terpenos/toxicidade , Poluentes Atmosféricos/análise , Ascomicetos/efeitos dos fármacos , Briófitas/química , Bryopsida , Clorofila/farmacologia , Clorofila A , Biomarcadores Ambientais , Monitoramento Ambiental/métodos , Madeira/química
4.
J Environ Radioact ; 222: 106383, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32861137

RESUMO

The determination procedure of low 137Cs concentrations in air using γ-spectrometry is essential wherever the net counts are smaller than the background of the spectrum. Such measurements have performed in April 2020 during the Chernobyl wildfires period. A significant event recorded in Thessaloniki's atmosphere during April 12, 2020, with 25.7 ± 0.7 µBq m-3 of 137Cs, was measured. Besides, a minor incident with a lower 137Cs concentration of 9.6 ± 0.8 µBq m-3 has occurred on April 21, 2020. The above results resemble to a previous one noticed during winter 2013, when signals up to 12.1 ± 0.8 µBq m-3 of 137Cs detected in the atmosphere, due to extensive use of 137Cs contaminated wood for residential heating. The results obtained demonstrate that no radiation hazard rose for the general public due to inhalation of the 137Cs in the air of Thessaloniki, Greece. Moreover, the residence time of the aerosol-bound 137Cs has estimated. The data presented are useful for basic simulation-inputs and comparison with global atmospheric models, which also discussed after comparison with the back trajectories predicted by the NOAA-HYSPLIT model.


Assuntos
Poluentes Radioativos do Ar , Radioisótopos de Césio , Acidente Nuclear de Chernobyl , Monitoramento de Radiação , Madeira , Poluentes Radioativos do Ar/análise , Atmosfera , Radioisótopos de Césio/análise , Florestas , Grécia , Madeira/química
5.
Proc Natl Acad Sci U S A ; 117(29): 16776-16781, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636260

RESUMO

A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morphological changes in poplar wood biomass during tetrahydrofuran (THF):water pretreatment and provide a mechanism by which the solvent components drive efficient biomass breakdown. Whereas lignin dissociates over a wide temperature range (>25 °C) cellulose disruption occurs only above 150 °C. Neutron scattering with contrast variation provides direct evidence for the formation of THF-rich nanoclusters (Rg ∼ 0.5 nm) on the nonpolar cellulose surfaces and on hydrophobic lignin, and equivalent water-rich nanoclusters on polar cellulose surfaces. The disassembly of the amphiphilic biomass is thus enabled through the local demixing of highly functional cosolvents, THF and water, which preferentially solvate specific biomass surfaces so as to match the local solute polarity. A multiscale description of the efficiency of THF:water pretreatment is provided: matching polarity at the atomic scale prevents lignin aggregation and disrupts cellulose, leading to improvements in deconstruction at the macroscopic scale.


Assuntos
Biotecnologia/métodos , Lignina/química , Madeira/química , Proteínas de Bactérias/metabolismo , Biomassa , Celulase/metabolismo , Furanos/química , Gluconacetobacter xylinus/enzimologia , Hidrólise , Lignina/metabolismo , Populus/química , Solventes/química , Tensoativos/química
6.
Chemosphere ; 257: 127315, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32535364

RESUMO

The study was conducted to assess the performance of improved and traditional cookstoves using wood as a fuel and three combinations of other fuel mixes - (i) wood and cow dung, (ii) wood and mustard stalks, and (iii) cow dung and mustard stalks). Energy and emission parameters such as specific energy consumption (SEC), emission factors (EFs) of carbon monoxide (CO), particulate matter (PM) and black carbon (BC) were used to compare four different types of cookstoves. These included top-feed forced draft (TF-FD), top-feed natural draft (TF-ND), front-feed natural draft (FF-ND) and front-feed traditional (FF-TR) cookstoves. Controlled cooking test (CCT) was used as the test protocol. The results showed the performance of improved cookstove technologies can vary based on the fuel used for cooking. It was observed that emission factors for PM and CO increased by 67-96% and 45-90% respectively when all three improved cookstoves were tested with three fuel combinations against wood as cooking fuel. Among the tested cookstoves, a marked difference was observed between performance of forced draft and natural draft cookstoves. Forced draft cookstoves emitted higher amount of all pollutant emissions compared to natural draft cookstoves when used with mustard stalks in combination with either wood or cowdung. The results are of critical importance given that forced draft cookstoves have been promoted in geographical regions where fuel mix use is prevalent. Therefore, forced draft cookstove might not be the right choice when the goal is climate mitigation and reduction in impact on human health. It is imperative to study comprehensively the influence of various field variables on performance of cookstoves, which have severe implications on the performance of cookstoves.


Assuntos
Poluentes Atmosféricos/análise , Culinária/métodos , Poluição do Ar em Ambientes Fechados/análise , Monóxido de Carbono/análise , Utensílios Domésticos , Índia , Material Particulado/análise , Fuligem , Tecnologia , Madeira/química
7.
Sci Total Environ ; 739: 139488, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526531

RESUMO

Emissions from solid-fuel burning cookstoves are associated with 3 to 4 million premature deaths annually and contribute significantly to impacts on climate. Pellet-fueled gasifier stoves have some emission factors (EFs) approaching those of gas-fuel (liquid petroleum gas) stoves; however, their emissions have not been evaluated for biological effects. Here we used a new International Organization for Standardization (ISO) testing protocol to determine pollutant- and mutagenicity-EFs for a stove designed for pellet fuel, the Mimi Moto, and for two other forced-draft stoves, Xunda and Philips HD4012, burning pellets of hardwood or peanut hulls. The Salmonella assay-based mutagenicity-EFs (revertants/megajouledelivered) spanned three orders of magnitude and correlated highly (r = 0.99; n = 5) with EFs of the sum of 32 particle-phase polycyclic aromatic hydrocarbons (PAHs). The Mimi Moto/hardwood pellet combination had total-PAH- and mutagenicity-EFs 99.2 and 96.6% lower, respectively, compared to data published previously for the Philips stove burning non-pelletized hardwood, and 100 and 99.8% lower, respectively, compared to those of a wood-fueled three-stone fire. The Xunda burning peanut hull pellets had the highest fuel energy-based mutagenicity-EF (revertants/megajoulethermal) of the pellet stove/fuel combinations tested, which was between that of diesel exhaust, a known human carcinogen, and a natural-draft wood stove. Although the Mimi Moto burning hardwood pellets had the lowest fuel energy-based mutagenicity-EF, this value was between that of utility coal and utility wood boilers. This advanced stove/fuel combination has the potential to greatly reduce emissions in contrast to a traditional stove, but adequate ventilation is required to approach acceptable levels of indoor air quality.


Assuntos
Poluentes Atmosféricos/análise , Poluentes Ambientais , Culinária , Humanos , Mutagênicos , Material Particulado/análise , Madeira/química
8.
J Vis Exp ; (160)2020 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-32568225

RESUMO

Construction and demolition waste (CDW), including valuable materials such as plastics, have a remarkable influence on the waste sector. In order for plastic materials to be re-utilized, they must be identified and separated according to their polymer composition. In this study, the identification of these materials was performed using near-infrared spectroscopy (NIR), which identified material based on their physical-chemical properties. Advantages of the NIR method are a low environmental impact and rapid measurement (within a few seconds) in the spectral range of 1600-2400 nm without special sample preparation. Limitations include its inability to analyze dark materials. The identified polymers were utilized as a component for wood-polymer composite (WPC) that consists of a polymer matrix, low cost fillers, and additives. The components were first compounded with an agglomeration apparatus, followed by production by extrusion. In the agglomeration process, the aim was to compound all materials to produce uniformly distributed and granulated materials as pellets. During the agglomeration process, the polymer (matrix) was melted and fillers and other additives were then mixed into the melted polymer, being ready for the extrusion process. In the extrusion method, heat and shear forces were applied to a material within the barrel of a conical counter-rotating twin-screw type extruder, which reduces the risk of burning the materials and lower shear mixing. The heated and sheared mixture was then conveyed through a die to give the product the desired shape. The above-described protocol proved the potential for re-utilization of CDW materials. Functional properties must be verified according to the standardized tests, such as flexural, tensile, and impact strength tests for the material.


Assuntos
Materiais de Construção/análise , Plásticos/química , Resíduos/análise , Madeira/química
9.
Food Chem ; 329: 127181, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502743

RESUMO

The compounds that the wood releases to the wine and the oxygen transmission rate (OTR) of the barrel define the final wine. The new possibility of choosing the OTR of the barrel allows the winemaker to globally control the ageing process. The aim of this work was to study the volatile composition of woods classified according to their OTR, which are used to build barrels for wine ageing. The results showed that volatile composition differs depending on wood OTR and the temperature reached during toasting. On the toasted side of the stave in contact with the wine, low OTR wood had a statistically higher content in furan compounds (5-hydroxymethylfurfural, furfural and 5-methylfurfural), acetovanillone and phenolic aldehydes (vanillin and syringaldehyde), while 4-ethylguaiacol and trans-ß-methyl-γ-octalactone were significantly higher in staves with a high OTR. The same red wine aged first for three months in high and low oxygenation barrels presents different characteristics.


Assuntos
Manipulação de Alimentos/métodos , Oxigênio/química , Quercus/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Benzaldeídos/química , Cromatografia Gasosa , Análise Discriminante , Furanos/química , Guaiacol/química , Temperatura , Madeira/química
10.
J Vis Exp ; (159)2020 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-32478730

RESUMO

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the adhesive cure, and the effect of adhesive penetration on the wood interphase; thus, normal testing of a neat adhesive film is generally not useful. Most tests of wood adhesive bond strength are slow, laborious, can be strongly influenced by the wood and do not provide information on the kinetics of cure. Test method ASTM D 7998-19, however, can be used for fast evaluation of the strength of wood bonds. The use of a smooth, uniform, and strong wood surface, like maple face-veneer, and sufficient bonding pressure reduces the adhesion and wood strength effects on bond strength. This method has three main applications. The first is to provide consistent data on bond strength development. The second is to measure the dry and wet strengths of bonded lap shear samples. The third is to better understand the adhesive heat resistance by quickly evaluating thermal sensitivity and distinguishing between thermal softening and thermal degradation.


Assuntos
Adesivos/química , Teste de Materiais/métodos , Madeira/química , Resistência ao Cisalhamento
11.
PLoS One ; 15(5): e0233320, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428043

RESUMO

Image Quality Assessment (IQA) is essential for the accuracy of systems for automatic recognition of tree species for wood samples. In this study, a No-Reference IQA (NR-IQA), wood NR-IQA (WNR-IQA) metric was proposed to assess the quality of wood images. Support Vector Regression (SVR) was trained using Generalized Gaussian Distribution (GGD) and Asymmetric Generalized Gaussian Distribution (AGGD) features, which were measured for wood images. Meanwhile, the Mean Opinion Score (MOS) was obtained from the subjective evaluation. This was followed by a comparison between the proposed IQA metric, WNR-IQA, and three established NR-IQA metrics, namely Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE), deepIQA, Deep Bilinear Convolutional Neural Networks (DB-CNN), and five Full Reference-IQA (FR-IQA) metrics known as MSSIM, SSIM, FSIM, IWSSIM, and GMSD. The proposed WNR-IQA metric, BRISQUE, deepIQA, DB-CNN, and FR-IQAs were then compared with MOS values to evaluate the performance of the automatic IQA metrics. As a result, the WNR-IQA metric exhibited a higher performance compared to BRISQUE, deepIQA, DB-CNN, and FR-IQA metrics. Highest quality images may not be routinely available due to logistic factors, such as dust, poor illumination, and hot environment present in the timber industry. Moreover, motion blur could occur due to the relative motion between the camera and the wood slice. Therefore, the advantage of WNR-IQA could be seen from its independency from a "perfect" reference image for the image quality evaluation.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Madeira/análise , Algoritmos , Meio Ambiente , Interpretação de Imagem Assistida por Computador/métodos , Redes Neurais de Computação , Distribuição Normal , Árvores/fisiologia , Madeira/química
12.
Environ Sci Pollut Res Int ; 27(22): 27831-27848, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32399870

RESUMO

A Cu-resistant somaclonal tobacco variant (NBCu 10-8-F1, C1), its BaG mother clone (C3), and the FoP tobacco clone (C2) were cultivated at a wood preservation site on Cu-contaminated soils (239-1290 mg Cu kg-1 soil range) and an uncontaminated control site (CTRL, 21 mg Cu kg-1) to assess their shoot DW yields and potential use for bioavailable Cu stripping. The Cu concentration in the soil pore water varied between 0.15 and 0.84 mg L-1. Influences of Cu exposure and soil treatments, i.e., untreated soil (Unt), soils amended with compost and either dolomitic limestone (OMDL) or zerovalent iron grit (OMZ), on plant growth and shoot ionome were determined. All transplants survived and grew even at high total soil Cu. Shoots were harvested after 3 months (cut 1). Subsequently, bottom suckers developed and were harvested after 2 months (cut 2). Total shoot DW yield (cuts 1 + 2) varied between 0.8 and 9.9 t DW ha-1 year-1 depending on tobacco cultivars, soil treatments, and soil Cu exposure. It peaked for all cultivars in the OMDL plots at moderate Cu exposure (239-518 mg kg-1 soil), notably for the C2 plants. Cut 2 contributed for 11-43% to total shoot DW yield. Increase in shoot DW yield diluted shoot Cu concentration. At low Cu exposure, total shoot Cu removal peaked for the variant. At moderate Cu exposure, shoot Cu concentrations were similar in all cultivars, but total shoot Cu removal was highest for the C2 plants. At high Cu exposure (753-1140 mg kg-1), shoot Cu concentrations peaked for the C2 plants in the Unt plots, the C1 and C2 plants in the OMZ plot, and the C3 ones in the OMDL plots. Shoot Cu removal (in g Cu ha-1 year-1) ranged from 15.4 (C2 on the CTRL soil) to 261.3 (C2 on moderately contaminated OMDL soils). The C2 plants phytoextracted more Cu than the C1 and C3 ones in the Unt plots and in the OMDL plots at moderate Cu exposure. In the OMDL plots with high Cu exposure, shoot Cu removal was highest for the C1 plants. Soil amendments improved shoot Cu removal through increase in either shoot DW yield (OMDL-3-fold) or shoot Cu concentration (OMZ-1.3-fold). Increased shoot Cu concentration induced an ionome imbalance with increased shoot Al, Fe, B, and Mg concentrations and decreased P and K ones. Copper concentrations in plant parts varied in decreasing order: roots > leaves > inflorescence (cymes including seeds) > stem, whereas Cu removal ranked as roots > stem = leaves > inflorescence.


Assuntos
Cobre/análise , Poluentes do Solo/análise , Biodegradação Ambiental , Solo , Tabaco , Madeira/química
13.
Environ Sci Pollut Res Int ; 27(22): 27786-27795, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32399877

RESUMO

Heavy metals induce stress in plants, thereby affecting growth, crop quality, and food security. Most studies addressing the mitigation of these effects by soil amendment have focused on metals in soils and plant uptake, with there still being a great deal of uncertainty about how amendment application in polluted soils can modify plant stress response and, consequently, yield and food safety. Thus, the aim of this study was to evaluate the effect of biosolid compost amendment on stress response, growth, and lead accumulation in Glycine max, when applied to lead polluted agricultural soils. Soybean was grown in lead polluted soils with 0%, 5%, or 10% (w/w) biosolid compost amendment under controlled conditions in a greenhouse, and the stress response indicators chlorophylls, proteins, sugars, malondialdehyde, glutathione S-transferase activity, carotenes, and the ferric reducing antioxidant power were investigated. In addition, the biomass and lead accumulation in different organs were determined and evaluated with respect to the plant stress. Our results revealed that the addition of 10% biosolid compost improved the grain biomass and appeared to reduce the amount of defective grains, which was related to higher Pb concentrations. Furthermore, 10% compost treatment reduced the stress in plants, leading to a better performance of the photosynthetic system, and with the antioxidant response being positively correlated to Pb accumulation. Lead uptake in plants was decreased by between 35 and 57% after this treatment in comparison with unamended soils. These results indicate that biosolid compost amendment may be an effective way to alleviate Pb uptake and metal stress in soybeans.


Assuntos
Compostagem , Poluentes do Solo/análise , Biossólidos , Chumbo , Solo , Soja , Madeira/química
14.
J Oleo Sci ; 69(6): 649-657, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32378554

RESUMO

Microwave is an alternative method which can rapidly pyrolyze biomass by thermal treating, and produce clean syngas and bio-oil products. In this research, the wood particles microwave pyrolysis process was proposed for preparing bio-oil and syngas production. The wood particles were first pyrolyzed by microwave reactor in the process, and then the bio-oil products were separated by cyclone separator and multi-phase separator, syngas products were prepared by steam reforming reactor and absorption tower. Kinetics for larch microwave thermogravimetry reactions were proposed and correlated with lab-scale experiments; the microwave pyrolysis process was simulated in Aspen HYSYS, and the results showed that when pyrolysis reaction temperature and microwave power were 900℃ and 2.0 kW respectively, the maximum bio-oil and syngas production can be achieved. The H2/CO and CO2 content in syngas which can be used in chemical processes such as Fischer-Tropsch synthesis, can be controlled by the molar ratio function of steam and pyrolysis gas.


Assuntos
Extração Líquido-Líquido/métodos , Micro-Ondas , Óleos Vegetais/isolamento & purificação , Polifenóis/isolamento & purificação , Pirólise , Madeira/química , Biomassa , Temperatura Alta , Extração Líquido-Líquido/instrumentação , Vapor , Termogravimetria
15.
J Nat Med ; 74(3): 571-578, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32328863

RESUMO

Three new quassinoids, javanicinols A and B (1 and 2) and 4-keto-(16S)-methoxyjavanicin B (3), together with three known quassinoids (4-6) were isolated from the chloroform-soluble fraction of the methanol extract of the Picrasma javanica wood. The structures of 1-3 were determined by spectroscopic analyses, including 1D and 2D NMR, HRESIMS, and CD. The anti-HIV-1 viral protein R (Vpr) assay revealed that 1 and 2 exhibited potent anti-Vpr activities at 1.25 µM. Furthermore, the assay also revealed the potent anti-Vpr activities of (16R)-methoxyjavanicin B (7) and (16S)-methoxyjavanicin B (8), which were previously isolated from the Picrasma javanica wood.


Assuntos
Fármacos Anti-HIV/farmacologia , Produtos do Gene vpr/antagonistas & inibidores , HIV-1/efeitos dos fármacos , Picrasma/química , Quassinas/farmacologia , Fármacos Anti-HIV/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Quassinas/química , Quassinas/isolamento & purificação , Madeira/química
16.
Environ Pollut ; 263(Pt A): 114446, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283452

RESUMO

As a result of metal mining activities in Pakistan, toxic heavy metals (HMs) such as chromium (Cr) and lead (Pb) often enter the soil ecosystem, accumulate in food crops and cause serious human health and environmental issues. Therefore, this study examined the efficacy of biochar for contaminated soil remediation. Poplar wood biochar (PWB) and sugarcane bagasse biochar (SCBB) were amended to mine-contaminated agricultural soil at 3% and 7% (wt/wt) application rates. Lactuca sativa (Lettuce) was cultivated in these soils in a greenhouse, and uptake of HMs (Cr and Pb) as well as biomass produced were measured. Subsequently, health risks were estimated from uptake data. When amended at 7%, both biochars significantly (P<0.01) reduced plant uptake of Cr and Pb in amended soil with significant (P<0.01) increase in biomass of lettuce as compared to the control. Risk assessment results showed that both biochars decreased the daily intake of metals (DIM) and associated health risk due to consumption of lettuce as compared to the control. The Pb human health risk index (HRI) for adults and children significantly (P<0.01) decreased with sugarcane bagasse biochar applied at 7% rate relative to other treatments (including the control). Relative to controls, the SCBB and PWB reduced Cr and Pb uptake in lettuce by 69%, 73.7%, respectively, and Pb by 57% and 47.4%, respectively. For both amendments, HRI values for Cr were within safe limits for adults and children. HRI values for Pb were not within safe limits except for the sugarcane bagasse biochar applied at 7%. Results of the study indicated that application of SCBB at 7% rate to mine impacted agricultural soil effectively increased plant biomass and reduced bioaccumulation, DIM and associated HRI of Cr and Pb as compared to other treatments and the control.


Assuntos
Metais Pesados/análise , Saccharum , Poluentes do Solo/análise , Adulto , Celulose , Carvão Vegetal , Criança , Cromo , Ecossistema , Humanos , Chumbo , Alface , Paquistão , Solo , Madeira/química
17.
Tree Physiol ; 40(8): 1014-1028, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32268376

RESUMO

Compression wood (CW) is a common tissue present in the trunk, branches and roots of mechanically stressed coniferous trees. Its main role is to increase the mechanical strength and regain the vertical orientation of a leaning stem. Compression wood is thought to influence the climate signal in different tree-ring measures. Hence trees containing CW are mostly excluded from tree-ring studies reconstructing past climate variability. There is a large gap of systematic work testing the potential effect of CW on the strength of the climate signal in different tree-ring parameters, especially stable isotope records. Here we test for the first time the effect of CW contained in montane Norway spruce (Picea abies L. Karst) on both δ13C and δ18O tree-ring cellulose records by analyzing compression and opposite wood radii from several disturbed trees together with samples from undisturbed reference trees. We selected four trees tilted by geomorphic processes that were felled by wind and four undisturbed reference trees in the Tatra Mountains, Poland. We qualitatively classified the strength of CW using wood cell anatomical characteristics (tracheid shape, cell wall thickness and presence of intercellular spaces). Then we developed tree-ring width and δ13C and δ18O chronologies from the CW radii, from the opposite radii of the tilted trees and from the reference radii. We tested the effect of CW on tree-ring cellulose δ13C and δ18O variability and on the climate signal strength. We found only minor differences in the means of δ13C and δ18O of compression (δ13C: -22.81‰, δ18O: 28.29‰), opposite (δ13C: -23.02‰; δ18O: 28.05‰) and reference (δ13C: -22.78‰; δ18O: 27.61‰) radii. The statistical relationships between climate variables, δ13C and δ18O, remained consistent among all chronologies. Our findings suggest that moderately tilted trees containing CW can be used to reconstruct past geomorphic activity and for stable isotope-based dendroclimatology.


Assuntos
Picea , Isótopos de Carbono/análise , Noruega , Isótopos de Oxigênio/análise , Polônia , Árvores , Madeira/química
18.
Proc Natl Acad Sci U S A ; 117(15): 8649-8656, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32234787

RESUMO

For more than 225 million y, all seed plants were woody trees, shrubs, or vines. Shortly after the origin of angiosperms ∼140 million y ago (MYA), the Nymphaeales (water lilies) became one of the first lineages to deviate from their ancestral, woody habit by losing the vascular cambium, the meristematic population of cells that produces secondary xylem (wood) and phloem. Many of the genes and gene families that regulate differentiation of secondary tissues also regulate the differentiation of primary xylem and phloem, which are produced by apical meristems and retained in nearly all seed plants. Here, we sequenced and assembled a draft genome of the water lily Nymphaea thermarum, an emerging system for the study of early flowering plant evolution, and compared it to genomes from other cambium-bearing and cambium-less lineages (e.g., monocots and Nelumbo). This revealed lineage-specific patterns of gene loss and divergence. Nymphaea is characterized by a significant contraction of the HD-ZIP III transcription factors, specifically loss of REVOLUTA, which influences cambial activity in other angiosperms. We also found the Nymphaea and monocot copies of cambium-associated CLE signaling peptides display unique substitutions at otherwise highly conserved amino acids. Nelumbo displays no obvious divergence in cambium-associated genes. The divergent genomic signatures of convergent loss of vascular cambium reveals that even pleiotropic genes can exhibit unique divergence patterns in association with independent events of trait loss. Our results shed light on the evolution of herbaceousness-one of the key biological innovations associated with the earliest phases of angiosperm evolution.


Assuntos
Câmbio/química , Genoma de Planta , Magnoliopsida/genética , Nymphaea/genética , Proteínas de Plantas/genética , Madeira/química , Câmbio/genética , Câmbio/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Magnoliopsida/crescimento & desenvolvimento , Nymphaea/crescimento & desenvolvimento , Filogenia , Transcriptoma , Madeira/genética , Madeira/crescimento & desenvolvimento
19.
Ecotoxicol Environ Saf ; 194: 110442, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32171121

RESUMO

In recent decades, indoor air quality (IAQ) has become one of the most important human health issues. The potential properties and potential health hazards of polycyclic aromatic hydrocarbons (PAHs) are associated with their long-term residues, bioaccumulation and semivolatility, and they can also be transferred through a variety of media, such as the atmosphere, water and soil. Dust particles from indoor and outdoor emission sources adhere to A-C filters and can represent air quality to a certain extent. However, few studies have focused on PAHs in A-C filter dust in Hefei, China. In this study, 16 PAHs were selected, dust samples were collected from A-C filters from three different functional districts, and GC-MS analysis of the samples was performed. The concentration of the ∑16PAHs ranged from 7.34 to 326.84 µg g-1, 5.07-15.34 µg g-1, 4.09-47.26 µg g-1 and 0.97-13.38 µg g-1 in dust samples from the Administrative District (AD), Industrial District (ID), Commercial District (CD) and Outdoors (OD), respectively. The total PAH concentration in A-C dust was much higher than that in dust deposited outdoors in the urban area. The percentage of 5-6 ring PAHs accounted for more than 70% of the ∑16PAHs, which shows that the PAHs in A-C dust mainly come from pyrolysis rather than a diagenetic source. Principal component analysis (PCA) and diagnostic ratios were used in a source analysis, and the results indicated that the main PAHs emission sources in the different functional districts were coal, wood and biomass combustion. The incremental lifetime cancer risk (ILCR) values indicated a medium to high potential carcinogenic risk for adults and children exposed to dust with PAHs. Particularly, skin contact and ingestion of carcinogenic PAHs from dust are the major exposure pathways and present an exposure risk that is four to five orders of magnitude higher than the risk of inhalation.


Assuntos
Ar Condicionado , Poluição do Ar em Ambientes Fechados/análise , Exposição Ambiental/estatística & dados numéricos , Hidrocarbonetos Policíclicos Aromáticos/análise , Adulto , Poluição do Ar/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Atmosfera , Carcinógenos/análise , Criança , Carvão Mineral/análise , Poeira/análise , Monitoramento Ambiental/métodos , Humanos , Indústrias , Neoplasias , Análise de Componente Principal , Medição de Risco , Solo , Madeira/química
20.
PLoS One ; 15(3): e0229907, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182254

RESUMO

To investigate the effects of urea-formaldehyde (UF) resin impregnation combined heat treatment (IMPG-HT) on the pyrolysis behavior of poplar wood, the chemical composition, pyrolysis characteristics, pyrolysis kinetics, and gaseous products released during pyrolysis of untreated (control), IMPG-HT, IMPG and HT woods were analyzed. The results demonstrate that IMPG-HT changes pyrolysis behavior of poplar wood significantly. Unlike the control and HT samples, the thermogravimetric / derivative thermogravimetric (TG/DTG) curves of IMPG wood shift toward lower temperature, and the shoulder on DTG curves weaken or even disappear. The maximum mass loss rate of IMPG-HT samples decreases, and carbon residual yield increases to 23% or more and activation energy (E) increases sharply after conversion rate (α) reaching 0.80. HT improves the thermal stability of IMPG wood, which is represented by the increase of decomposition temperature (Td) and DTG peak temperature (Tpeak) and the higher E value of IMPG-HT wood. For the pyrolysis gaseous products, IMPG-HT wood produces nitrogen-containing gases (HNCO and NH3) due to the presence of UF resin, but the amounts of these gases are less than that produced by IMPG wood because the heat treatment had removed part of N elements.


Assuntos
Biomassa , Formaldeído/química , Pirólise/efeitos dos fármacos , Ureia/química , Madeira/química , Temperatura Alta , Cinética , Populus/química , Temperatura , Madeira/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA