Search Results (6)

Desired retention and depth into wood are necessary for wood preservatives to provide long-term durability. In general, heartwood of wood is difficult to treat, and bioincising was investigated as a potential technique to improve the treatability of refractory wood and heartwood. In order to study the effects of bioincising treatment with white-rot fungus Trametes versicolor on the pore structure and treatability of radiata pine heartwood, this research conducted tests of mass loss, microscopic structures, pore structure parameters, uptake, and penetration of preservative of radiata pine heartwood specimens incubated by T. versicolor for 4, 8, and 12 weeks. The results showed that the optimal inoculation time of T. versicolor bioincising on radiata pine heartwood was 4 to 8 weeks. At this time, the retention of injected preservatives increased by 5.01%–17.73%, the penetration depth of preservatives increased significantly, and the corresponding mass loss was 3.04%–6.45%. The results of microstructure and pore structure showed that T. versicolor entered the adjacent tracheids via apertures, with less impact on the cell wall, mainly degrading pit membranes and ray parenchyma cells early in the inoculation of radiata pine heartwood. As the structures impeding fluid flow were connected, the porosity of the wood and the range of the main pore size distribution increased significantly, thus increasing the treatability of radiata pine heartwood. Full article

Introduction: Right heart catheterization (RHC) is a diagnostic procedure, the main purpose of which is to diagnose pulmonary hypertension and investigate its etiology and treatability. In addition to measuring blood pressure in heart chambers, it includes estimating cardiac output (CO) and calculation of pulmonary vascular resistance (PVR) derived from the CO. There are two common methods to evaluate the CO—the indirect Fick method and the thermodilution method. Depending on the clinical conditions, either of the two may be considered better. Several studies have showed that, in most cases, there is no difference between measurements rendered by the two methods. Other studies have raised suspicion of a discrepancy between the two methods in a substantial number of patients. A clear opinion on this matter is missing. Aim: To evaluate the agreement between the values of the CO and PVR found by the thermodilution and indirect Fick methods. Methods: We retrospectively included patients that underwent RHC in Kaplan Medical Center during the last two years with a measurement of the CO using both the thermodilution and the indirect Fick methods. The measurements obtained upon RHC and the clinical data of the patients were collected. The values of the CO and PVR measured or calculated using the two methods were compared for each patient. Results: We included 55 patients that met the inclusion criteria in this study. The mean CO measured by the thermodilution method was 4.94 ± 1.17 L/min and the mean CO measured by the indirect Fick method was 5.82 ± 1.97 L/min. The mean PVR calculated using the thermodilution method was 3.33 ± 3.04 Woods’ units (WU) and the mean PVR calculated using the indirect Fick method was 2.71 ± 2.76 WU. Among the patients with normal mPAP, there was a strong and statistically significant correlation between the PVR values calculated by the two methods (Peasron’s R² = 0.78, p-value = 0.004), while among the patients with elevated mPAP, the correlation between the PVR values calculated by the two methods was not statistically significant. Conclusion: The findings of this small study demonstrate that, in a proportion of patients, the indirect Fick method and thermodilution method classify the PVR value differently. In our experience, it seems that, in these patients, the indirect Fick method misclassified patients with a pathological finding as normal. We, therefore, recommend that upon performing RHC, at least in patients with mPAP > 25 mmHg, both the thermodilution and indirect Fick methods be performed and, whenever they disagree, the values obtained from the thermodilution method should be preferred. Full article

The success of any wood treatment process and the measure of protection conferred on treated wood are determined by the uptake and penetration of the treatment chemicals, in addition to the efficacy of the chemicals used for the treatment. Hence, the level of treatability of wood species should be pre-determined prior to the wood treatment to ensure the overall protection of the treated wood. Gmelina arborea wood, due to its low durability, requires impregnation with chemicals for preservation or chemical modification to enhance its durability. However, more details are required to establish the influence of its anatomy on impregnation to recommend appropriate treatment methods. Therefore, gmelina wood samples were treated under pressure to determine the solution uptake and penetration, while anatomical studies were carried out with light microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) measurements. Variations in stem heights, stem diameters, and samples from other tree stands were considered. The outcome of the study showed that the liquid uptake was generally low for gmelina wood among the selected stands (16%–23%) and there was no significant difference in stem diameters; meanwhile, penetration was less than 4 mm in the axial direction, and very low in the lateral (radial and tangential) direction. Vessels of gmelina wood have abundant tyloses, while crystalline structures with needlelike shapes are present in a large proportion of the ray parenchyma cells, and are confirmed with SEM-EDX to be made up of calcium oxalate. The low liquid uptake and penetration in gmelina wood suggest that the impregnation of chemicals into its microstructure is next to impossible. Hence, alternative treatment methods other than those involving impregnation with chemicals should be sought to enhance its durability. Full article

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H₂ availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes. Full article

The impregnation of low-molecular-weight monomers prior to polymerize them inside the wood may be an efficient way to improve some important wood properties. This work aimed to determine some technological properties of wood-based composites (WPC) produced by in situ polymerization, using a pine wood (Pinus elliottii Engelm.) impregnated with methyl methacrylate (MMA). For that, samples taken from both juvenile (JV) and mature (MT) pine woods were treated with MMA. Physical, mechanical, chemical, thermal and morphological features were evaluated. MMA-treated woods from both juvenile and mature woods presented superior physical, mechanical (expect brittleness) and thermal properties when compared to pristine ones. The infrared spectra and morphological analysis by scanning electron microscopy (SEM) confirmed the presence of the monomer inside the pine wood. The juvenile wood presented higher treatability than the mature wood, due to its higher content of intra- and inter-cellular spaces. Full article

In this study, feather was used as the source of protein and combined with copper and boron salts to prepare wood preservatives with nano-hydroxyapatite or nano-graphene oxide as nano-carriers. The treatability of preservative formulations, the changes of chemical structure, micromorphology, crystallinity, thermal properties and chemical composition of wood cell walls during the impregnation and decay experiment were investigated by retention rate of the preservative, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), thermoanalysis (TG), and confocal Raman microscopy (CRM) techniques. Results revealed that the preservatives (particularly with nano-carrier) successfully penetrated wood blocks, verifying the enhanced effectiveness of protein-based preservative with nano-carrier formulations. Decay experiment demonstrated that the protein-based wood preservative can remarkably improve the decay resistance of the treated wood samples, and it is an effective, environmentally friendly wood preservative. Further analysis of these three preservative groups confirmed the excellent function of nano-hydroxyapatite as a nano-carrier, which can promote the chelation of preservatives with higher content of effective preservatives. Full article