Wood Matrix Research Articles

Pre-cleaned bare wooden toothpicks for the determination of drugs in oral fluid by mass spectrometry

This article deepens the potential of pre-cleaned bare wooden toothpicks (pb-WTs) for extracting drugs (antidepressants and acetaminophen) from oral fluid samples. The leaching of the intrinsic compounds from the wood matrix is identified as the main challenge for the final determination of the targets, even when a very selective instrumental technique, such as mass spectrometry, is employed. The pre-cleaning of the WTs is proposed for improving the analytical performance. The number of cleaning cycles depends on the injection mode (direct infusion or chromatography) into the mass spectrometer. The different variables affecting the extraction of selected antidepressant drugs were studied in detail, and the optimum procedure was validated using the two mentioned injection modes. The limits of detection were in the ranges 0.1–0.5 ng/mL and 0.1–0.3 ng/mL for direct infusion and liquid chromatography, respectively. The intra-day precision (expressed as relative standard deviation) was better than 12.1% and 8.6%, for direct infusion and liquid chromatography, respectively. Single-blind samples were used to study the applicability of the method. Finally, as a proof-of-concept, the potential of pb-WTs for in vivo sampling was outlined.Graphical abstract

Heat treatment induces chemical changes and silica sol penetration in wood for properties improvement: hydrophobicity, thermal stability, and surface hardness

Thermal modification could act as pretreatment for promoting silica sol impregnation in wood. It could create extra available channels and spaces for silica transportation and deposition owing to the presence of micro-cracks and enlarged pore size. The significant improvements on anti-hygroscopicity, hydrophobicity, and dimensional stability of treated wood were attributed to the degradation of cell wall polymer (hemicellulose, cellulose, and lignin) and filling effect of silica in wood. The synergistic effect contained the reduction on –OH concentration owing to thermal degradation, and consumption of –OH groups via the interaction (Si–O–Si cross linked networks and Si–O–C covalent bonds) between silica and wood matrix. Furthermore, the degradation of cell wall polymers resulted in the increase of crystallinity in wood. However, the crystallinity turned to decrease due to the amorphous silica impregnation. The silica impregnation could compensate the mass loss caused by thermal degradation, leading to various weight percentage gains (WPGs) that depended on treatment temperature. Moreover, owing to the coverage and penetration of mineral silica in wood, acting as a thermal barrier, the thermal stability and surface hardness of treated wood improved prominently.

Using High-Resolution Digital Photography and Micro-CT Scanning to Investigate Deathwatch Beetle Damage to an Historic Timber from HMS Victory

ABSTRACT Wood-boring insects such as the deathwatch beetle can cause significant damage to historical artefacts and timbers, but the extent of internal damage (and tunnelling activity in general) can be difficult to understand and quantify without the use of destructive sampling techniques. This study explored the potential of high-resolution photography and micro-computed tomography (micro-CT) to investigate beetle activity and inform on the extent of internal damage to a timber from HMS Victory. Micro-CT imaging has allowed the visualisation of deathwatch beetle activity within the timber, revealing differences in tunnelling behaviour preferences for adult and larval forms. Digital techniques were developed to determine the surface area of flight holes on some wooden blocks but were less successful for those blocks where the external surfaces were darkened with age. It was not possible to accurately determine the internal volumes of beetle tunnels within blocks of timber due to the presence of frass, which was found to be virtually indistinguishable digitally from the wood matrix.

Wooden Tips as Sustainable Supports in Liquid Phase Microextraction: A Closer View of the Influence of Wood Matrix

Wooden Tips as Sustainable Supports in Liquid Phase Microextraction: A Closer View of the Influence of Wood Matrix

Hive‐Inspired Multifunctional Wood‐Nanotechnology‐Derived Membranes with a Double‐Layer Conductive Network Structure for Flexible Electronics

AbstractNext‐generation flexible electronics must achieve multifunctionality, environmental friendliness and antibacterial activity. Accordingly, organisms in nature are interconnected. Inspired by the honeycomb multilayer porous structure, a wood‐nanotechnology‐derived flexible membrane circuit is created to meet the abovementioned requirements. The flexible wood (FW) matrix is made of natural balsa wood that underwent a simple top‐down chemical treatment. The multiwalled carbon nanotube (MWCNT) acts as a “bridge” between the FW matrix with a porous array structure and the active material (silver nanoparticles (Ag NPs) and poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Due to the three‐dimensional porous microstructure and highly conductive surface inherited by the wood‐nanotechnology‐derived flexible membrane (FW/MWCNT/Ag/PEDOT:PSS), it shows a high area capacitance (266.7 mF cm−2 at 20 mV s−1) and a good long‐term cycling stability 84.3% capacitance retention after 5000 cycles at 5 mA cm−2 when used as a supercapacitor electrode. In addition, it shows an excellent specific electromagnetic shielding efficiency (up to 970 dB cm2 g−1), proving its application potential in the field of electromagnetic shielding. Because of the biocidal property of Ag NPs, the FW/MWCNT/Ag/PEDOT:PSS shows a remarkable antibacterial effect on Escherichia coli and Staphylococcus aureus. This strategy provides a new opportunity for researchers to design biomass‐based integrated electronic materials.

Genome-Wide Identification and Characterization of HSP70 Gene Family in Aquilaria sinensis (Lour.) Gilg.

The heat shock protein 70 (HSP70) gene family perform a fundamental role in protecting plants against biotic and abiotic stresses. Aquilaria sinensis is a classic stress-induced medicinal plant, producing a valuable dark resin in a wood matrix, known as agarwood, in response to environmental stresses. The HSP70 gene family has been systematic identified in many plants, but there is no comprehensive analysis at the genomic level in A. sinensis. In this study, 15 putative HSP70 genes were identified in A. sinensis through genome-wide bioinformatics analysis. Based on their phylogenetic relationships, the 15 AsHSP70 were grouped into six sub-families that with the conserved motifs and gene structures, and the genes were mapped onto six separate linkage groups. A qRT-PCR analysis showed that the relative expression levels of all the AsHSP70 genes were up-regulated by heat stress. Subcellular localization of all HSP70s was predicted, and three were verified by transiently expressed in Arabidopsis protoplasts. Based on the expression profiles in different tissues and different layers treated with Agar-Wit, we predict AsHSP70 genes are involved in different stages of agarwood formation. The systematic identification and expression analysis of HSP70s gene family imply some of them may play important roles in the formation of agarwood. Our findings not only provide a foundation for further study their biological function in the later research in A. sinensis, but also provides a reference for the analysis of HSPs in other species.

In Polymerization of Environment Friendly Melamine-Urea-Glyoxal Resin in Rubber Wood for Improved Physical and Mechanical Properties

In the study, we report that a safe and simple way for upgrading inferior rubber wood through the combined modification of environment-friendly MUG resin was synthesized from glyoxal, melamine, urea, and other additives. MUG-treated wood samples were prepared with six different MUG resin concentrations (5, 15, 25, 35, 45, and 55 wt %) into the wood matrix and then heated and polymerized to form a solid and hydrophobic MUG resin in the wood scaffold, and the physico-mechanical properties were evaluated. As the MUG resin concentration increased, the weight percent gain and density increased, water uptake and leachability decreased, and the antiswelling efficiency increased at first and then decreased. MUG-treated wood sample can be prepared when the MUG resin concentration was set as 25%, and the physical properties of treated wood was optimum. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis showed that the MUG resin is widely distributed in the cell lumens and cell walls. With enhanced physico-mechanical properties, MUG-treated wood sample can be well used as a promising alternative to existing engineered wood products for structural applications.

Carbonized wood membrane decorated with AuPd alloy nanoparticles as an efficient self-supported electrode for electrocatalytic CO2 reduction

Efficient electrocatalytic reduction of CO2 to value-added chemicals and fuels is a promising technology for mitigating energy shortage and pollution issues yet highly relay on the development of high-performance electrocatalysts. Herein, we develop an effective strategy to fabricate carbonized wood membrane (CW) decorated with AuPd alloy nanoparticles with tunable composition (termed as AuPd@CW) as self-supported electrodes for efficient electrocatalytic CO2 reduction. The uniformly distributed AuPd nanoparticles on wood matrix are first achieved through the in-situ reduction of metal cations by the lignin content in wood. Subsequently, two-step carbonization was employed to promote the alloying of AuPd nanoparticles and the formation of CW. The AuPd@CW membrane electrode features an integrated macroscopic structure with numerous open and aligned channels for rapid electron transfer and mass diffusion and well-dispersed AuPd alloy nanoparticles as active sites for the CO2 reduction. The optimal Au95Pd5@CW electrode affords a high selectivity for CO2 electroreduction with a maximum CO faradaic efficiency (FECO) of 82% at an overpotential of 0.49 V, much higher than those obtained on Au@CW and Pd@CW electrodes. The CO current density and FECO remain relatively stable during a 12 h electrolysis reaction. In addition, density functional theory (DFT) calculations reveal that alloying Au with Pd enables a balance between the formation of intermediate COOH* and the desorption of CO on the surface of AuPd nanoparticles, thus enhancing the selectivity of CO production. This work offers an effective strategy for the fabrication of bimetallic alloys supported on wood-based carbon membrane as a practical electrode for electrochemical energy conversion.

Sustainable afterglow materials from lignin inspired by wood phosphorescence

Sustainable organic afterglow room-temperature phosphorescence (RTP) is a particularly attractive phenomenon but remains difficult to achieve. Herein, inspired by the afterglow RTP of natural basswood, we prepare a series of sustainable afterglow RTP materials by confining lignin within a 3D poly(acrylic acid) network that mimics the wood matrix. The RTP emission of these materials could be finely tuned either by varying the drying temperature or the crosslinking density. Afterglow RTP emission could also be produced by embedding different types of lignin in a variety of 3D polymeric networks, thus demonstrating the generality of our strategy for preparing sustainable lignin-based RTP materials. As an illustration of potential applications, the lignin-based RTP materials are used to coat cotton fibers, which are then incorporated into luminescent textiles. • Room-temperature phosphorescence (RTP) of lignin in natural wood is reported • Sustainable afterglow RTP materials are prepared from lignin • As-prepared lignin-based afterglow RTP materials have a tunable lifetime Inspired by the afterglow room-temperature phosphorescence (RTP) of natural wood, Yuan et al. prepare sustainable afterglow RTP materials by confining lignin within a 3D molecular matrix, which paves a route for sustainable RTP materials.

Molecular self-organization of wood lignin-carbohydrate matrix.

The analysis of the state of research on the chemical composition, functional nature and structure of the main components of the lignin-carbohydrate matrix allows considering the wood substance as a thermodynamically self-organizing nanobiocomposite system. Features of biosynthesis of the wood matrix main biopolymers, the formation of their functional nature and structure determine the complex hierarchical organization of cell walls. The supramolecular level of biosynthesis considers the interaction of cell wall components. On the one hand, these are questions of dynamics of cell walls synthesis and processes of self-organization that control the formation of chaotic objects of biological origin; on the other hand, it is the question of thermodynamic compatibility of plant tissue components. Various models of structural organization are currently being considered, focusing on various features (biological, chemical, structural) of wood substance. At the same time, the lignin-carbohydrate matrix is a three-component system of natural polymers: lignin-hemicelluloses-cellulose, the state of which is described by specific values of thermodynamic parameters that characterize the degree of its stability. The new approach proposed in this paper allows considering the plant lignin-carbohydrate matrix from the standpoint of physical chemistry of polymer as quasi-equilibrium, thermodynamically limited ordered system of biopolymers. Thus, the biochemical processes of synthesis and self-organization lead to the formation of a complex multicomponent system of wood substance, considered as a nanobiocomposite. This determines the need to study the applicability of the fundamental cycle "structure-functional nature-properties" from the standpoint of physical chemistry of biopolymers both for the investigation of plant objects and for the development of modern technologies for complex processing based on the principles of "green chemistry".

Differences in the physicochemical properties of lignins in the heartwood and sapwood of Pinus sylvestris

Lignin polymers are among the main components of the cell wall and characterized by the highest reactivity due to their polyfunctional nature, the presence of reactive centers and a conjugated polymolecular aromatic structure. Investigation of differences in functional composition, macromolecular, reaction and electrophysical properties of slightly altered preparations of dioxane lignin extracted from the heartwood and sapwood of pine was carried out in this paper. The increased content of carboxyl groups in the heartwood lignins leads to a decrease in the reaction (acid-base and redox) properties and specific electrical conductivity. Changes in the physicochemical properties of lignins in the wood matrix indicate the continuous transformation of the natural polymer during the life cycle of plants.

Mathematical Model Coupled to Neural Networks Calculates the Extraction Recovery of Polycyclic Aromatic Hydrocarbons in Problematic Matrix.

Unknown extraction recovery from solid matrix samples leads to meaningless chemical analysis results. It cannot always be determined, and it depends on the complexity of the matrix and properties of the extracted substances. This paper combines a mathematical model with the machine learning method—neural networks that predict liquid extraction recovery from solid matrices. The prediction of the three-stage extraction recovery of polycyclic aromatic hydrocarbons from a wooden railway sleeper matrix is demonstrated. Calculation of the extraction recovery requires the extract’s volume to be measured and the polycyclic aromatic hydrocarbons’ concentration to be determined for each stage. These data are used to calculate the input values for a neural network model. Lowest mean-squared error (0.014) and smallest retraining relative standard deviation (20.7%) were achieved with the neural network setup 6:5:5:4:1 (six inputs, three hidden layers with five, five, and four neurons in a layer, and one output). To train such a neural network, it took less than 8000 steps—less than a second––using an average-performance laptop. The relative standard deviation of the extraction recovery predictions ranged between 1.13 and 5.15%. The three-stage recovery of the extracted dry sample showed 104% of three different polycyclic aromatic hydrocarbons. The extracted wet sample recovery was 71, 98, and 55% for phenanthrene, anthracene, and pyrene, respectively. This method is applicable in the environmental, food processing, pharmaceutical, biochemical, biotechnology, and space research areas where extraction should be performed autonomously without human interference.

Carbonized Wood Decorated with Cobalt‐Nickel Binary Nanoparticles as a Low‐Cost and Efficient Electrode for Water Splitting

AbstractUsing an inexpensive and eco‐friendly wood substrate, herein, a one‐step calcination method is developed to deposit Co‐Ni binary nanoparticles into aligned wood channels and an effective carbonized wood (CW) electrode (termed as Co/Ni‐CW) is fabricated. Well distributed Co‐Ni nanoparticles are achieved by the coordination bonds between the hydroxyl groups on wood matrix and soaked metal cations. Subsequently, high‐temperature calcination promotes the nucleation of Co‐Ni nanoparticles and the formation of CW. With the uniform distribution of Co‐Ni nanoparticles and porous wood structure, not only is a high active surface area, but also the electron and mass diffusion pathways are enhanced. Thus, the as‐prepared Co/Ni‐CW affords the current density of 10 mA cm–2 at low overpotentials of 330 and 157 mV for oxygen and hydrogen evolution, respectively. Remarkably, when the wood‐based bifunctional electrocatalyst is used as both the anode and cathode, a low cell voltage of 1.64 V is required to reach the current density of 10 mA cm–2. Compared with most substrates used in bifunctional electrocatalysts, the abundance, low cost, eco‐friendliness, and easy operation of wood‐based catalysts allow for an active and scalable electrode for water splitting and many other energy storage devices.

Differences and similarities between kraft and oxygen delignification of softwood fibers: effects on chemical and physical properties

The fiber properties after oxygen delignification and kraft pulping were studied by looking into the chemical characteristics and morphology. The effect of the two processes on the fibers was evaluated and compared over a wider kappa number range (from 62 down to15). Wide-angle X-ray scattering, nuclear magnetic resonance and fiber saturation point were used to characterize the fiber network structure. Fiber morphology and fiber dislocations were evaluated by an optical image analysis. The total and surface fiber charges were studied by conductometric and polyelectrolyte titrations. The fiber wall supramolecular structure, such as crystallinity, size of fibril aggregates, pore size and pore volume, were similar for the two processes. The selectivity, in terms of carbohydrate yield, was equal for kraft cooking and oxygen delignification, but the selectivity in terms of viscosity loss per amount of delignification is poorer for oxygen delignification. Clearly more fiber deformations (2–6% units in curl index) in the fibers after oxygen delignification were seen. Introduction of curl depended on the physical state of the fibers, i.e. liberated or in wood matrix. In the pulping stage, the fiber continue to be supported by neighboring fibers, as the delignified chips maintain their form. However, in the subsequent oxygen stage the fibers enter in the form of pulp (liberated fibers), which makes them more susceptible to changes in fiber form.Graphic abstract

Kinetics of Formation of Flavano‐C‐Glycosidic Ellagitannins (Acutissimin A and B) in Model Solutions Containing Medium Toasted Oak Chips and Catechin for Wine Aging

AbstractThe aging process of wine goes beyond conservation and involves the use of wood, which is capable of containing and protecting, and allows a limited passage of oxygen, sufficient to promote slow maturation of the wine, thanks to which it reaches the maximum of its organoleptic qualities. The most used wood is oak and during aging, the wine extracts from the wood of the barrels an abundant quantity of aromatic substances, due to the contact between the wine and the matrix of the wood. Among the newly formed compounds, the flavano‐ellagitannins, namely the acutissimin A and B, are the minor compounds found in wood aged wine. They are formed during the aging process through the condensation of tannins, such as vescalagin, extracted from the wood matrix and flavonoids, such as catechins contained in wine. The aim of the study is to verify the formation of acutissimins after 28 days in model solutions that simulated aged wine in the presence of 1%, 5%, and 10% w/v percentages of wood chips obtained from Quercus alba and with variable concentrations of catechin (100 and 500 mg L−1). The formation of compounds, including acutissimin A and B, and the disappearance of catechin are identified by high‐performance liquid chromatography/electrospray ionization/mass spectrometry. Acutissimins A and B are validated by comparison with the characteristic m/z reported in the literature. Based on the results obtained, the model system prepared with 500 mg L−1 of catechin and 10% w/v oak chips showed the highest content of acutissimin A and B.

Borate and Quaternary Ammonia Dip Diffusion to Treat Fungal Pathogens of Metrosideros polymorpha Wood

Abstract Rapid Ohia Death is a major concern for the viability of ohia (Metrosideros polymorpha) in Hawaii and has led to restrictions on log movement. The potential for using disodium octaborate tetrahydrate (DOT) and didecyl dimethyl ammonium chloride (DDAC) dip diffusion treatments to control the two causal fungi (Ceratocystis lukuohia and Ceratocystis huliohia) was investigated. A 10 percent boric acid equivalent dip diffusion treatment killed the pathogens in 0.5-cm-thick disks obtained from 4.0- to 5.0-cm-diameter limbs of naturally colonized trees. DOT tended to diffuse more consistently in 50- to 60-cm-long bolts of small (4.0 to 9.0 cm) and large (9.1 to 17.0 cm) diameter healthy ohia compared with those bolts naturally infected by C. lukuohia. Diffusion periods longer than 6 weeks resulted in deeper penetration. Immersion (24 h) of logs (1.3 m long; 9 to 17 cm diameter) from C. lukuohia artificially inoculated trees in two forest locations in a 15 percent DOT/1 percent DDAC solution and storage for 10 weeks before evaluation resulted in incomplete elimination of the pathogen and lower boron concentrations in the inner sapwood than outer. Further investigations are needed to explore using either higher boron concentrations or longer diffusion periods to deliver fungicidal concentrations of boron deeper within the wood matrix.

Mineralization of wooden elements by bypass cement kiln dust

The application of renewable and waste materials for the production of building materials is currently one of the main trends, especially with regard to environmental aspects. This is a reduction in the volume of materials that could be a waste and at the same time a reduction in the cost (including carbon footprint) for special wood treatment products that would have to be produced. One example given in this article is the possible application of a mineralization of wood matrix by kiln dust produced in a cement plant. This treatment can be primarily used in the production of wood-based panels bonded with cement, whose main purpose is to limit the leaching of soluble components, which affect the setting of the cement. If the cement kiln dust is applied for the mineralization of wooden elements, the flammability of wood can be positively influenced. Bypass cement kiln dusts contain significant amount of chloride, which in this case function as a reducing agent. In this article, the effect of the wood mineralization by the cement kiln dust from CEMMAC a.s. Horné Srnie was investigated on thermal degradation of wood by a simultaneous thermal analysis TG / DSC.

Dissolution reaction kinetics and mass transfer during aqueous choline chloride pre-treatment of oak wood

Lignocellulosic biomass processing employing ionic liquids is of recent research interest for the biorefinery industry. The data on biomass dissolution kinetics in ionic liquids is important for designing scale-up pre-treatment reactor design. In this study, the reaction mechanism and kinetics of oak wood dissolution in aqueous choline chloride was investigated. In an extended effort, a correlation of dimensionless numbers was developed for the estimation the mass transfer coefficient. The analyses suggested that oak wood dissolution in choline chloride occurred in two stages. The diffusion of ionic liquid through the product layer was the dominating rate-controlling step in the first stage of dissolution followed by the surface chemical reaction in the second stage. The diffusivity of choline chloride into the oak wood matrix was ranging between 2.96E−14 and 2.84E−13 m2/s. The activation energy of the diffusion controlled stage and surface chemical reaction controlled stage was approximately 24.2 and 40.3 kJ mol−1, respectively. The proposed mathematical correlation for mass transfer coefficient fitted well with the experimental mass transfer coefficient values.

Compounding and technological methods for increasing the efficiency of wood matrix mineralization

This paper presents the results of a study of the efficiency of mineralization of the plant matrix of pine wood samples by immersion of experimental samples in an organo-mineral water suspension (dispersion medium) and holding for 24 hours under natural conditions, as well as under autoclave impregnation at an excess pressure of up to 1.5 MPa. To create the necessary working pressure in the autoclave, an inert gas (argon) was used. As working fluids, we used an aqueous solution of arabinogalactan, aqueous suspension containing polymineral sand, pre-dispersed to a fine state and a soluble complex obtained by mechanical mixing of the above components. Prototypes were made from ordinary pine wood. The effectiveness of impregnation was evaluated by increasing the density of samples. In addition, data on changes in Brinell hardness, compressive strength of samples along the fibers, and water absorption of impregnated wood were obtained. It was found that autoclaving in the studied mode leads to an increase in the density of samples by more than two times, reduces their water absorption, and increases strength by 84%.

Wood delignification with aqueous solutions of deep eutectic solvents

The development of a sustainable wood fractionation has been a goal for the pulp and paper industries to develop a bioeconomy. The use of green solvents, in particular deep eutectic solvents (DES) has been explored to accomplish such goal. This work unveils the potential of DES aqueous solutions (at 50 wt% water content) as green solvents for the Eucalyptus globulus Labill. wood delignification. Aqueous solutions of propionic acid:urea - PA:U (2:1), urea:choline chloride - U:Ch[Cl] (2:1), lactic acid:choline chloride - LA:Ch[Cl] (10:1) and p-toluenesulfonic acid:choline chloride - PTSA:Ch[Cl] (1:1) were investigated. The delignification process was assisted by the addition of mineral (H2SO4 and HCl) or organic (PTSA) acids to efficiently promote wood matrix disruption and further lignin extraction. This process enabled solid pulp and lignin as separated fractions, which were characterized by analytical, optical and spectrometric methods. The influence of each DES on the morphology of cellulose fibers in solid pulp and the chemical structure of isolated lignin fractions was evaluated. The best system allowing delignification while preserving the cellulose fibers (comparable to Kraft cellulose pulp) and lignin structure was PA:U (2:1) aqueous solution with 25 wt% PTSA. A mild wood delignification process (363.15 K for 8 h) using this DES allowed to obtain a cellulose pulp yielding 59.50 ± 0.51 wt% of the initial wood mass and containing only 3.86 ± 0.10 wt% residual Klason lignin content. This innovative approach led to 80.64 wt% lignin extraction from E. globulus wood at mild conditions showing its potential for industrial application. Furthermore, 40.73 wt% of the initial lignin was recovered from DES liquor by a simple precipitation with water.