Volume 15 Issue 3

Tissue and organ failure or loss is a major problem for human health, and the construction of tissue engineering porous scaffold materials is a core step in the repair of damaged tissue and organs. Fibers from the lotus (Nelumbo nucifera) plant can be a source of superfine fibers. Such fibers have excellent biocompatibility, and they are easy to convert into nanofibers that could be applied for tissue engineering. Lotus fibers were carboxyl-modified with the TEMPO/NaClO/NaBr system, and lotus nanofibers were prepared. The effect of oxidation conditions on their morphologies and degrees of oxidation were investigated. The diameters of the lotus nanofibers were about 15 nm. Additionally, the degrees of oxidation of lotus nanofibers increased with an increase of oxidation time. Moreover, the oxidized sodium alginate membranes crosslinked with carboxymethyl chitosan degraded quickly, with the degradation rates increased by 82.1% or 100.0% during a 14-day period. By increasing the dosage of carboxymethyl chitosan, the pH values tend to rise. In comparison, the degradation rates of the lotus nanofibers/alginate porous membranes crosslinked with carboxymethyl chitosan exhibited better performance in terms of microstructure, porosity, water absorption, mechanical properties (0.36 MPa /7.7%), and in vitro degradation (59.2%).

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

A new perspective on the effect of unconditioned indoor (especially storage areas) and outdoor environments on wood acidity is provided in this work. A comparison between the quantity and types of the organic acids formed in the unconditioned indoor environment and different outdoor environments was made. Moreover, the acidity of some wood samples due to different environmental conditions was determined using a pH meter and high-performance liquid chromatography (HPLC). Fourier transform infrared (FTIR) was used to detect the changes in wood components at the molecular level due to environmental conditions. The results suggest that the unconditioned indoor environment was more aggressive than the outdoor environment with respect to wood deterioration. The polluted atmosphere increased the wood acidity and motivated polysaccharide breakdown.

Lignin depolymerization through an oxidation method could provide value-added products, but it is challenging in terms of recovering catalysts or separating products in time to avoid over-oxidation. In this study, a process of selectively oxidative degradation of lignin model compounds was operated in a two-phase reaction system. Lignin model compounds of 4-benzyloxyphenol (PBP) or guaiacylglycerol-β-guaiacyl ether (GGE) in a bottom phase of 1-butyl-3-methylimidazole chloride ([BMIM]Cl) ionic liquid were selectively oxidized by H2O2 in the presence of a solid acid (SO42-/Fe2O3-ZrO2), and the degradation products immediately diffused into the upper organic solvent phase (butyl acetate). In this kind of reaction system, the yield of the products was improved due to the prolonged life of ∙OH in ionic liquid, and the product selectivity was maintained due to the timely product separation, and the ionic liquid and the catalyst were easily recycled.

Log temperature appreciably influences veneer quality during the rotary peeling process. The assessment of the thermal properties of green wood is complex and typically requires the sawing of small calibrated samples. This study introduced a simple approach based on an inverse identification method to determine the global log thermal diffusivity online and without the time-consuming extraction of wooden samples that is commonly used to perform diffusivity experiments. This method was applied to green Douglas fir logs and resulted in an average thermal diffusivity of 0.175 ± 0.021 mm2.s-1. This method was found to be suitable for both heartwood and sapwood and thus can provide a globally applicable diffusivity assessment method. This global parameter is essential to optimizing the soaking time and improving the subsequent veneer production quality. As log-soaking preprocessing requires an immense input of energy, this time-optimization strategy will allow sizable cost reduction and ecological improvement.

Declining availability of the prime economic species in the Nigerian timber market has led to the introduction of Lesser-Used Species (LUS) as alternatives. Their acceptability demands information on the technical properties of their wood. The aim of this study was to investigate the mechanical properties of Ficus vallis-choudae to determine its potential for timber. Three mature Ficus vallis-choudae trees were selected and harvested from a free forest area in Ibadan, Oyo State, Nigeria. Samples were collected from the base (10%), middle (50%), and top (90%) along the sampling heights of each tree, which was further partitioned into innerwood, centrewood, and outerwood across the sampling radial position. Investigations were carried out to determine the age, density, moisture content, impact strength, modulus of elasticity, modulus of rupture, compressive strength parallel-to-grain, and shear strength parallel-to-grain. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel-to-grain, and maximum compression strength parallel-to-grain for Ficus vallis-choudae at 12% moisture content were 20.4 N/mm2, 85.8 N/mm2, 709 N/mm2, 10.7 N/mm2, and 33.6 N/mm2, respectively. The study found the species to be dense with high strength properties in comparison with well-known timbers used for constructional purposes.

Recent studies have suggested that blocky mechanical pulp fines (CTMP fines) and fibrillar fines (SMC fines) have a negative impact on biocomposite modulus of rupture (MoR) in compression molded biocomposites. In addition, it was suggested that CTMP fines also have a negative impact on biocomposite modulus of elasticity (MoE). This study investigated whether these findings transfer to other types of cellulose fines material and injection molding. The effect of ‘V-fines’ addition to sawdust- and TMP-based biocomposites was analyzed, with respect to fines concentration, dispersing agent, and compatibilizers. The results indicated that the addition of ‘V-fines’ increased the stiffness (MoE) of all the analyzed compositions, while reducing the elongation at break. The addition of ‘V-fines’ reduced the tensile and flexural strength of TMP biocomposites, while it was largely unaffected for sawdust biocomposites. Flexural strength for neat ‘V-fines’ composites showed an increase that was proportional to the remaining pulp fibers composition. The addition of a dispersant agent to the ‘V-fines’ increased tensile strength, suggesting that an increased dispersion of the ‘V-fines’ can be achieved and is beneficial to the composite. The effects of the analyzed compatibilizer (polyethyleneoxide) was negligible, except for a small indication of increased MoE for fines / sawdust biocomposites.

Borax-agar gel has been used recently in the deacidification and other conservation processes for paper manuscripts. However, the residues of borax-agar can be damaging to the cellulose fibers. Conservators are trying to solve this problem, especially with the great success achieved by the borax / agar based gel in the acidity neutralization and improve the mechanical properties of the paper manuscripts. The current study considers whether the use of paper barriers such as Japanese gampi, linen, and rayon can reduce harmful borax-agar residues. Historical paper specimens were treated with 3% and 6% of agar poultice with different barriers such as rayon, pure linen, and Japanese gampi paper. After drying, the treated paper samples were exposed to hot-moist ageing at 80 °C and 65% relative humidity for 72 h. The role of different barriers used in the reduction of residues from agar poultice and the effect of these residues on cellulose fibers were studied via some analytical techniques, such as digital optical microscopy, scanning electron microscopy, pH, color change, and Fourier-transform infrared spectroscopy (FTIR), were used. The results showed that 3% of the agar poultice-borax with a linen barrier gave the best results with no residue left after treatment.

The structural changes of biochar prepared from sweet sorghum bagasse during fast pyrolysis of 200 to 700 °C in a novel V-shaped down-tube reaction device was investigated by ultimate analysis, bomb calorimeter, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and N2/CO2 adsorption methods. The results showed that the pyrolysis temperature had an important effect on the composition and physicochemical properties of sweet sorghum bagasse biochar. With the increase of pyrolysis temperature, the yield of biochar and the polar functional groups decreased, but the higher heating values and mineral salts increased. However, the surface area, pore volume, and adsorption (N2, CO2) increased first and then decreased. The biochar obtained at 500 °C had the most developed pore structures. The experimental results shed light on the high-quality utilization of sweet sorghum bagasse obtained from advanced solid-state fermentation.

The anatomical characteristics of the stem of belangke bamboo (Gigantochloa pruriens), which is native in North Sumatra, Indonesia, were examined to attain valuable information for identification and effective utilization. The number and type of vessel bundles and the fiber and metaxylem dimensions in the longitudinal (bottom, middle, and top) and radial (outer, central, and inner) directions of the bamboo culm were investigated by optical microscopy. The vascular bundles were distributed unevenly and arranged alternately, as shown by cross-sectional images of the culms. The proportion of vascular bundles in the culm decreased from the outer layer to the inner layer and tended to increase from the bottom to the top. Most vascular bundles were classified as type IV at the bottom and as type III in the middle and top parts. Fiber length and cell wall thickness tended to increase from the bottom to the top and from the inner layer to the outer layer. Metaxylem length and diameter increased from the outer layer to the inner layer and from the bottom towards the top of the stem. It was revealed that the anatomical characteristics of the belangke bamboo varied significantly in the vertical and radial directions.