Evaluation of the antifungal efficiency of coatings on wood.

Wood is an important construction material, but a significant problem hindering its widespread use is susceptibility to biodeterioration and biodegradation. To protect wood against degradation, a surface coating can be used, and it is important to be able to predict the ability of the coating to prevent fungal growth. The currently available standard method to determine the antifungal efficiency of a coating has two weaknesses, viz. no evaluation of the moisture content in the wood material, and no possibility to study antifungal effect of the coating towards an individual fungus. A new quantitative method of determining the antifungal efficiency of coatings is therefore proposed, where a coating is applied to wood and exposed to an individual fungus in a Petri dish. Six commercial water-based coatings containing synthetic biocides were studied on filter paper (EN 15457) and with the new test method on wood blocks. The results show the importance of studying the antifungal efficiency of a coating using individual fungi instead of a mixture of fungi, since individual fungi interact differently with a given biocide in the coating. The moisture content of the wood substrate during the test was affected by how the fungus was established on the coating. This new test approach shows promise in screening the antifungal efficiency of wood coatings containing preservative substances applied to wood material surfaces.publishedVersio

Coupling of the AQUATOX and EFDC Models for Ecological Impact Assessment of Chemical Spill Scenarios in the Jeonju River, Korea

Simple Summary This study proposed a methodology to simulate ecological damage in a toluene spill situation by coupling AQUATOX, an established ecological assessment model, and EFDC, a Lagrangian fluid diffusion model. TheAQUATOX-EFDC simulation showed a significant ecological impact, especially the greatest damage on the fish species group, the top predators. In this study, an ecological impact was assessed for the short-term leak scenario through the AQUATOX-EFDC model, which combines the proven ecological model AQUATOX with the hydrodynamic model EFDC. A case study of the coupled AQUATOX-EFDC model was conducted for 30-30,000 kg toluene leak scenarios in the Jeonju River in South Korea. A 21-day scenario simulation was conducted, and the impact of the toluene spill accident was evaluated by comparing the biomass between the control simulation and the perturbed simulation. As a result of the simulation, it was found that in the scenario in which 3000 kg of toluene was leaked for a day, a substantial change was expected in the range of 0-640 m from the accident site. Additionally, for a 30,000 kg leak, a substantial change was expected in the range of 0-2300 m from the accident site, and the greatest damage was observed for the fish species group, the top predators. As a result, the AQUATOX-EFDC simulation showed a significant ecological impact, and the proposed model will be helpful to understand the ecological impact and establish the management strategy for the ecological risk of the chemical spill

Chemical bonds formed in solid wood by reaction with maleic anhydride and sodium hypophosphite.

The reaction of wood with maleic anhydride (MA) and sodium hypophosphite (SHP) has been identified as a viable modification method, with macroscopical properties indicating formation of cross-linking to explain the results. However, the chemical reaction between wood and the modification reagents has not been studied yet. To resolve this, the reaction was studied with solid-state 13C cross-polarization magic-angle-spinning (CP-MAS) and 31P MAS nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) to reveal the formation of bonds between wood components, MA and SHP during the treatments to explain the formation of cross-linking and the possible fixation of phosphorus in wood. XPS, solid state 13C and 31P MAS NMR revealed the maleation of wood in the absence of SHP, whilst its presence led to forming a succinic adduct observed through the C-P bond formation, as evidenced by the loss of the maleate C=C bonds at around 130 ppm and the upfield shift of the peak at 165–175 ppm, which was also significantly smoothed, as well as the increase in a peak at 26 ppm due to the reaction between the maleate group and SHP; however, the C-P-C bond could not be unambiguously rationalized from the obtained data. On the other hand, a resonance line at 16 ppm in 31P MAS NMR and the peaks in the XPS P 2p spectrum suggested the formation of a cross-linked structure at low concentrations of SHP, which was more likely to be phosphonate (C-P-O) than organophosphinic acid (C-P-C). The results herein provide a greater fundamental understanding of the mechanisms involved in the reaction of wood, MA and SHP, providing further scope for improved treatment systems in the future.publishedVersio

The Association Between Dietary Inflammatory Index (DII) and Cancer Risk in Korea: A Prospective Cohort Study within the KoGES-HEXA Study

Several epidemiological studies have shown that there are consistently positive associations between dietary inflammatory index (DII (R)) scores and cancer incidence in Western populations. However, few DII-cancer studies have been conducted in East Asian populations. In a large cohort representative of the general Korean population, we investigated whether the DII is associated with overall cancer risk. A total of 163,660 participants (56,781 males and 106,879 females) had evaluable data for analyses. This follow-up study was carried out over the course of 7.9 years. DII scores were calculated based on Semi-Quantitative Food-Frequency Questionnaire (SQ-FFQ) data for 106 food items. Cancers were self-reported based on notification by the participants\u27 medical doctors. Multivariable Cox proportional hazard regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). After the follow-up, 1643 incident cases of cancer (520 males and 1123 females) had developed. In a fully adjusted model, women in the highest DII quintile showed a 44% increased risk of getting cancer (HRQ5vsQ1 = 1.44; 95% CI = 1.14-1.82; p-trend = 0.0006), while men showed no apparent association (HRQ5vsQ1 = 0.80; 95% CI = 0.58-1.10). These results indicate that in Korean women, a more pro-inflammatory diet is associated with a higher risk of incident cancer

Wood Modification with Maleic Anhydride and Sodium Hypophosphite

Wood has been a crucial material for construction throughout history. However, due to poor natural durability of wood, it is difficult to use outdoors without any additional treatment. Conventionally, wood has been fully or partially impregnated with preservatives. However, some substances are harmful to mankind and environment, hence, regulated strictly. Therefore, methods for achieving sustainable protection of wood have been required and one method that has been investigated for achieving this has been through chemical modification.  This doctoral thesis aims to develop a new modification system for solid wood in use class 3. The objective was to develop a wood modification system based on maleic anhydride (MA) and sodium hypophosphite (SHP) that enables exterior use without leaching by weathering. To meet this requirement, the modification should involve formation of stable cross-linking, altering the interaction between moisture and wood, consequently enhancing dimensional stability and biological resistance.  To test the possibility of using MA and SHP, Scots pine sapwood (Pinus sylvestris L.) was treated with various ratio of chemical reagents, curing temperatures and durations. The treated wood was subjected to repetitive wet-dry cycle to assess its dimensional stability and leachability of chemical reagents. The result indicated formation of a stable cross-linking between wood constituents.  To further investigate the formation of cross-link, solid-state 13C cross-polarization magic-angle-spinning (CP-MAS) nuclear magnetic resonance (NMR), 31P MAS NMR and X-ray photoelectron spectroscopy (XPS) were employed. The findings indicated that the cross-linking was likely to involve phosphonate (C-P-O) bonds. These results provided a deeper fundamental understanding of the reaction mechanisms between wood, MA and SHP, providing further scope for improved treatment systems in the future. The impact of the modification on wood-water interactions was analyzed using low-field nuclear magnetic resonance (LFNMR) to study water in the wood at a saturated state. Additionally, the hydrophilicity of cell walls was studied via infrared spectroscopy after deuteration using liquid D2O. The results indicated that the modification reduced the affinity of the wood cell wall to water without altering the number of accessible hydroxyl groups.   Finally, the modified wood was evaluated for fungal decay resistance, mechanical strength test (bending), and thermal stability. The modification significantly reduced mass loss caused by wood-decaying fungi by limiting the moisture uptake in wood and altering the chemical structure of wood. On the other hand, the modification did not improve resistance to fungal growth on the wood surface, suggesting that nutrient accessibility on surface was not influenced by the modification. A bending test showed that while the modulus of elasticity (MOE) was not affected, modulus of rupture (MOR) decreased to half that of untreated wood. Thermal resistance was improved due to the presence of phosphonate, which can promote the formation of a protective char layer and radical moieties.  This study demonstrated the potential of modifying wood with MA and SHP to enhance durability, dimensional stability, and fire resistance. The modification formed stable cross-link within the wood components, reducing water interaction and improving resistance to biological degradation. However, the reduction in MOR limits its suitability for load-bearing applications. Despite this, the results suggest that the modified wood could be a viable alternative for non-load bearing exterior applications. Future research should focus on optimising the modification process by reducing temperature, duration, and solvent use while maintaining performance. Investigating catalysts for the reaction may help address these challenges. Additionally, long-term field testing under real environmental conditions is needed to evaluate the durability and stability of the modified wood. Environmental impact assessments and life cycle analysis will also be crucial for ensuring commercial feasibility and sustainability

Wood Modification with Maleic Anhydride and Sodium Hypophosphite

Wood has been a crucial material for construction throughout history. However, due to poor natural durability of wood, it is difficult to use outdoors without any additional treatment. Conventionally, wood has been fully or partially impregnated with preservatives. However, some substances are harmful to mankind and environment, hence, regulated strictly. Therefore, methods for achieving sustainable protection of wood have been required and one method that has been investigated for achieving this has been through chemical modification.  This doctoral thesis aims to develop a new modification system for solid wood in use class 3. The objective was to develop a wood modification system based on maleic anhydride (MA) and sodium hypophosphite (SHP) that enables exterior use without leaching by weathering. To meet this requirement, the modification should involve formation of stable cross-linking, altering the interaction between moisture and wood, consequently enhancing dimensional stability and biological resistance.  To test the possibility of using MA and SHP, Scots pine sapwood (Pinus sylvestris L.) was treated with various ratio of chemical reagents, curing temperatures and durations. The treated wood was subjected to repetitive wet-dry cycle to assess its dimensional stability and leachability of chemical reagents. The result indicated formation of a stable cross-linking between wood constituents.  To further investigate the formation of cross-link, solid-state 13C cross-polarization magic-angle-spinning (CP-MAS) nuclear magnetic resonance (NMR), 31P MAS NMR and X-ray photoelectron spectroscopy (XPS) were employed. The findings indicated that the cross-linking was likely to involve phosphonate (C-P-O) bonds. These results provided a deeper fundamental understanding of the reaction mechanisms between wood, MA and SHP, providing further scope for improved treatment systems in the future. The impact of the modification on wood-water interactions was analyzed using low-field nuclear magnetic resonance (LFNMR) to study water in the wood at a saturated state. Additionally, the hydrophilicity of cell walls was studied via infrared spectroscopy after deuteration using liquid D2O. The results indicated that the modification reduced the affinity of the wood cell wall to water without altering the number of accessible hydroxyl groups.   Finally, the modified wood was evaluated for fungal decay resistance, mechanical strength test (bending), and thermal stability. The modification significantly reduced mass loss caused by wood-decaying fungi by limiting the moisture uptake in wood and altering the chemical structure of wood. On the other hand, the modification did not improve resistance to fungal growth on the wood surface, suggesting that nutrient accessibility on surface was not influenced by the modification. A bending test showed that while the modulus of elasticity (MOE) was not affected, modulus of rupture (MOR) decreased to half that of untreated wood. Thermal resistance was improved due to the presence of phosphonate, which can promote the formation of a protective char layer and radical moieties.  This study demonstrated the potential of modifying wood with MA and SHP to enhance durability, dimensional stability, and fire resistance. The modification formed stable cross-link within the wood components, reducing water interaction and improving resistance to biological degradation. However, the reduction in MOR limits its suitability for load-bearing applications. Despite this, the results suggest that the modified wood could be a viable alternative for non-load bearing exterior applications. Future research should focus on optimising the modification process by reducing temperature, duration, and solvent use while maintaining performance. Investigating catalysts for the reaction may help address these challenges. Additionally, long-term field testing under real environmental conditions is needed to evaluate the durability and stability of the modified wood. Environmental impact assessments and life cycle analysis will also be crucial for ensuring commercial feasibility and sustainability

Application of a Solid Ceramic Membrane for Monitoring Volatile Organic Compounds in Industrial Wastewater

A large quantity of volatile organic compounds (VOCs) can be released into water environments from oil spills and chemical exposure accidents. A recently developed solid ceramic dosimeter (SCD) could be used for long-term measuring of low VOCs concentrations in water. However, calibration and field testing of these SCDs have thus been far insufficient to apply for VOCs monitoring in a water environment in a chemical industrial area. We conducted laboratory calibration experiments and stability tests of the SCD. The mass accumulation of 14 target VOCs from 2 to 100 μg/L was increased linearly with time in the sampler. The absorption rate of the VOCs was related to Henry’s law constant. The average diffusion coefficient of the 14 VOCs in the SCD wall was 1.02 × 10−9 m2/s. The SCD was utilized in a petrochemical plant complex in South Korea with an industrial wastewater reservoir. After a total of 7 days of deployment, chloroform, ethylbenzene, and toluene were detected by both passive sampling and grab sampling at the same VOC concentrations

Application of a Solid Ceramic Membrane for Monitoring Volatile Organic Compounds in Industrial Wastewater

A large quantity of volatile organic compounds (VOCs) can be released into water environments from oil spills and chemical exposure accidents. A recently developed solid ceramic dosimeter (SCD) could be used for long-term measuring of low VOCs concentrations in water. However, calibration and field testing of these SCDs have thus been far insufficient to apply for VOCs monitoring in a water environment in a chemical industrial area. We conducted laboratory calibration experiments and stability tests of the SCD. The mass accumulation of 14 target VOCs from 2 to 100 μg/L was increased linearly with time in the sampler. The absorption rate of the VOCs was related to Henry’s law constant. The average diffusion coefficient of the 14 VOCs in the SCD wall was 1.02 × 10−9 m2/s. The SCD was utilized in a petrochemical plant complex in South Korea with an industrial wastewater reservoir. After a total of 7 days of deployment, chloroform, ethylbenzene, and toluene were detected by both passive sampling and grab sampling at the same VOC concentrations.</jats:p