Volume 19 Issue 3

The impregnability of Portuguese maritime pine (Pinus pinaster Ait.) subjected to microwave (MW) drying was tested, and the hydrophobicity, anti-swelling efficiency (ASE), and water repellence efficiency (WRE) were evaluated. Small wood heartwood samples of Portuguese maritime pine and two distinct MW treatment settings were employed. The levels of ASE and WRE of the wood elements were evaluated throughout four cycles of drying in an oven and soaking in water. Because of MW applied energy, the wood pine samples were satisfactorily impregnated with the preservative product. Regarding the absolutely dry densities of the samples, very subtle reductions were measured, and they were statistically equivalent to the average density of the non-MW-treated group. Slight improvements were identified in the WRE values of wood samples dried in the microwave. In terms of ASE, both MW-treated groups had a statistically significant increase. The MW treatment decreased the volumetric swelling of the maritime pine wood specimens. Hence, this study raises new insights and previously unexplored paths that can contribute to the expansion and greater application of MW technology in maritime pine and other species.

Activated carbon (AC) materials, renowned for their high specific surface area, excellent conductivity, and customizable functional groups, are widely employed as catalyst carriers. However, enhancing the activity of Ru-based catalysts supported on AC (Ru/AC) for ammonia decomposition remains a challenge. In this study, commercial AC was utilized as a substrate, with glucose and urea employed as modifiers. Specifically, the surface of the AC was modified via a hydrothermal pyrolysis method, resulting in the successful post-treatment in situ co-doping of nitrogen (AC-GN). Experimental results revealed that Ru/AC-GN exhibited a hydrogen production rate 46% higher than that of Ru/AC at 475 °C, indicating improved activity and stability. The characterization of AC-GN demonstrated that nitrogen doping primarily occurred on the external surface and macropores of the AC, increasing the nitrogen content in the carrier, particularly pyrrolic nitrogen content, while preserving the original structural and morphological integrity of the AC. The enhanced dispersion of Ru, combined with the improved electronic transmission capabilities and strengthened interactions between the metal and the modified carrier, were identified as pivotal factors contributing to the enhanced low-temperature efficacy of Ru/AC-GN. This paper presents a novel direction for the large-scale preparation of efficient catalysts for ammonia decomposition.

Reaction wood is a wood defect arising during the growth of the tree in the part of the trunk that is under tension (hardwood tree species) or compression (coniferous tree species). Beech (Fagus sylvatica L.) tension wood has different anatomical and chemical characteristics than normal (opposite) wood. The difference in density is conditioned by the percentage of the gelatinous layer (G-layer). Fibre cells in reaction beech wood have a different cell wall structure and a different chemical composition. Tension wood cannot be detected by the naked eye. It is only possible to assume its occurrence based on the macroscopic characteristics of the logs, such as a woolly surface, taper or eccentric pith, and so forth. However, these are imprecise and unreliable methods that have minimal effectiveness, especially when shortening the length of the log for cut-outs. This study aimed to create a unique chemical reagent for the detection of tension wood in logs and timber and wood products immediately. The present research can contribute to the mitigation of flaws resulting from the reaction of wood in timber production while addressing noticeable constraints in manufacturing, such as energy resources and the availability of wood raw materials. This can be achieved through the efficient identification of reaction wood in materials. The colour change is only temporary and will fade over time. After the chemical reagent has dried on the surface, the surface can be milled. The colour change extends to a depth of approx. of 3 to 5 mm.

Corn straw-based board has great potential for the protection of forest resources, waste recycling, and sustainable economic development. However, corn stalk-based board has poor mechanical properties due to its short fiber length and poor water resistance because of the presence of numerous hydrophilic hydroxyl functional groups in its structure. Natural mycelium originating from waste Pleurotus ostreatus substrate is a hydrophobic bio-adhesive. In the present study, formaldehyde-free corn stalk/P. ostreatus substrate bio-composites were prepared using the hot-pressing technique without the addition of any chemical adhesive. The mechanical properties and water resistance of the prepared bio-composites were excellent. The highest internal bonding strength (IBS) of 2.16 MPa and the minimum thickness swelling (TS) of 18.3% were observed, which are beyond the national standards for particleboard in China. These bio-composites were prepared using a simple, green, and convenient manufacturing method to promote their popularization and application. The method may, therefore, be used as a novel technical measure to resolve the problem of overuse of forestry resources and waste disposal.

Cross-laminated timber (CLT) fails in the outermost tensile lamina under bending loads, or rolling shear failure occurs in the Minoir direction lamina.  This study investigated the effect of lamina width (90 mm, 120 mm), modulus of elasticity (MOE), and placement of major direction lamina on the shear strength of Larix kaempferi Carr CLT. The shear test was conducted using the short span bending test. Results showed that the specimen with 90 mm width of lamina underwent rolling shear failure at the minor direction lamina. The specimen with 120 mm width of lamina had suppressed rolling shear failure and failed at the outermost tensile lamina, which resulted in 52% higher shear strength compared to the 90 mm width specimen. CLT with high MOE placed in the outermost tensile lamina had increased shear strength. The specimen with four laminas in the major direction had both the highest strength and the lowest reliability due to the high standard deviation. This suggested that the width of the larch lamina and the MOE affect the strength of CLT. The CLT strength obtained using the FEA and the theoretical analysis were compared with the measured strength values.

A continually increasing demand for papermaking materials and simultaneously growing disproportion between the request for fiber and the limited resources of wood have forced scientists and the papermaking industry to search for the new sources of fibrous raw materials. A new promising set of raw materials for papermaking comes from energy crops. This paper presents Sida hermaphrodita Rusby L., as a non-woody raw material for papermaking. From the studies of chemical composition, it follows that cellulose content of more than 40% characterizes phloem of stems and branches, whereas in xylem exhibits more than 32%. The lowest is the concentration of cellulose in leaves and flowers of Sida. The content of lignin is lower than 24% and 16% in stem xylem and phloem, respectively. In Sida, hemicelluloses and mineral substances stand for being not more than 30% and 2%, respectively. The morphology of Sida cells is similar to hardwood, with fiber length of 0.383, 0.470 and 1.025 mm for parenchyma, xylem, and phloem, respectively. The chemical composition of Sida hermaphrodita together with its morphological characteristics make this raw material suitable for a production of papers intended for printing, writing and tissue.

Green synthesis of silver nanoparticles was carried out using leaf extract from Calluna vulgaris. The formation of nanoparticles was confirmed through the emergence of a surface plasmon resonance band in ultraviolet-visible spectroscopy. The characterization conducted using various microscopic techniques revealed that the nanoparticles mostly ranged in size from approximately 20 to 70 nm. Analysis, including Fourier transform infrared spectrometry, X-ray diffraction, and energy-dispersive X-ray spectroscopy, confirmed the chemical, crystalline structure, and presence of silver, respectively. The synthesized nanoparticles exhibited notable stability with an average zeta potential of -23.1 ± 0.6 mV. Evaluation of their antibacterial activity against Staphylococcus aureus and Escherichia coli demonstrated significant efficacy with diameters of inhibition zones measuring 10.23 ± 0.54 mm and 15.38 ± 0.32 mm, respectively. Additionally, the nanoparticles displayed a remarkable inhibition of approximately 88% against E. coli biofilm formation at a concentration of 100 μg/mL. They also exhibited unique photocatalytic performances. This research contributes to the literature in this field by producing new silver nanoparticles with cost-effectiveness, stability, antibacterial, antioxidant, antibiofilm, and photocatalytic properties, while using a previously untapped plant extract for this purpose.

Ultraviolet B (UVB) irradiation causes photoaging, such as wrinkles, roughness and dryness of the skin, and it activates the production of reactive oxygen species (ROS) and inflammatory cytokines. In this study, the anti-photoaging activity of SEP-E (steam-exploded pine extract) was evaluated in HaCaT keratinocytes damaged by UVB irradiation. SEP-E treatment showed cytoprotective effects in HaCaT keratinocytes irradiated with UVB (40 mJ/cm²). SEP-E treatment reduced ROS overproduction and promoted the expression of antioxidant enzymes, such as catalase, superoxide dismutase 1, and superoxide dismutase 2. Additionally, SEP-E treatment suppressed the expression of inflammatory cytokines, including interleukin 6, interleukin 8, and monocyte chemoattractant protein-1. Consequently, SEP-E shows potential as a natural material for photoaging treatment.

Chemical fertilizers used in plant development and differentiation have become a global problem affecting the entire ecosystem, especially soil pollution. Food production demand with the increasing population has encouraged scientists to use biogenic nanoparticles in the agricultural field. Evaluation of growth, development, and differentiation processes of sweet basil (Ocimum basilicum L.) seedlings at gradually increasing concentrations of biogenic iron oxide nanoparticles (BIO-NPs) were identified by morphological and physiological parameters in this study. The results showed that growth parameters reached the maximum value at 100 mg/L but were less at other concentrations. At similar concentration, the stomatal density of the leaf was the maximum, while the stomatal area showed the lowest value. The levels of H₂O₂ and malondialdehyde (MDA) decreased in the treated seedlings. BIO-NPs increased the antioxidant defense and supported its growth by changing the antioxidant enzyme activities, H₂O₂, and MDA contents. The BIO-NP treatment provided positive improvements in phytochemical content in parallel with the growth and development of sweet basil seedlings. Different growth parameters, physiological results, supporting enzyme activities, and biochemical data revealed the contribution of the BIO-NP treatments to the growth and development of sweet basil seedlings. BIO-NPs improved higher phytochemical production of sweet basil, which may be suitable for its propagation on a commercial scale.

This research investigated and compared the pitting type, pit number (PN), and pit diameter (PD) in the cross-field of compression wood (CWD), lateral wood (LWD), and opposite wood (OWD) in stem wood of Pinus merkusii and Agathis loranthifolia growing in Indonesia. Identification and quality evaluation were done using optical and scanning electron microscopy. A piceoid pit type was observed in the CWD of both species. The LWD and OWD of P. merkusii showed window-like and pinoid pits, whereas those of A. loranthifolia showed taxodioid and cupressoid pits. The PN and PD were the smallest in CWD of both species. In P. merkusii, LWD and OWD showed similar PN values, and PN in all parts increased from the pith to the bark. In A. loranthifolia, LWD had higher PN than in OWD, and PN in CWD and LWD decreased from near the pith to the bark, whereas in OWD, it increased. All parts of P. merkusii and CWD and OWD of A. loranthifolia showed a positive correlation between PN and radial tracheid diameter, whereas LWD showed a negative correlation. In P. merkusii, the PD of LWD approximated that of OWD, whereas, in A. loranthifolia, LWD had a larger PD than that exhibited by OWD.