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Hydrothermal degradation deteriorates the fracture toughness and strength of tetragonal stabilised zirconia. The phase transformation to the monoclinic phase is particularly critical for materials with lower stabiliser content such as 2 mol% and 3 mol% yttria stabilised zirconia (2YSZ and 3YSZ). In this work, two routes in two-step sintering and co-doping with calcium oxide are analysed to mitigate the degradation. Both strategies show a reduction in average grain size of the 2YSZ while maintaining a comparable densification. The achieved smaller grains suppress the hydrothermal degradation rates. In addition, a mitigating effect beyond the reduction in grain size of YSZ is found for CaO doping. 1.6 mol% CaO co-doped 2YSZ shows less than 4% of monoclinic phase after 50 h in an autoclave with H 2 O at 134 °C. Pure 2YSZ contrarily reaches 100% monoclinic phase after 20 h at the same conditions. A suppression of degradation by CaO doping was also observed for the composite of nickel oxide and 3 mol% yttria stabilised zirconia. Hence, CaO co-doping can be an interesting strategy to increase resistivity against hydrothermal degradation for both biomedical and renewable energy applications. The findings further outline a route to achieve tetragonal YSZ with lower yttria contents than 2 mol%. • Two approaches were analysed to mitigate hydrothermal degradation in 2YSZ and 3YSZ. • Co-doping with CaO and two-step sintering reduced the grain growth and degradation. • CaO co-doping mitigated the degradation beyond the effect of the grain size. • A complete suppression of degradation was achieved by the addition of 1.6 mol% CaO. • The results show a route to ageing-resistant tetragonal YSZ with lower yttria contents. [ABSTRACT FROM AUTHOR]

Laser surface micropatterning of dental-grade zirconia (3Y-TZP) was explored with the objective of providing defined linear patterns capable of guiding bone-cell response. A nanosecond (ns-) laser was employed to fabricate microgrooves on the surface of 3Y-TZP discs, yielding three different groove periodicities (i.e., 30, 50 and 100 µm). The resulting topography and surface damage were characterized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). X-Ray diffraction (XRD) and Raman spectroscopy techniques were employed to assess the hydrothermal degradation resistance of the modified topographies. Preliminary biological studies were conducted to evaluate adhesion (6 h) of human mesenchymal stem cells (hMSC) to the patterns in terms of cell number and morphology. Finally, Staphylococcus aureus adhesion (4 h) to the microgrooves was investigated. The surface analysis showed grooves of approximately 1.8 µm height that exhibited surface damage in the form of pile-up at the edge of the microgrooves, microcracks and cavities. Accelerated aging tests revealed a slight decrease of the hydrothermal degradation resistance after laser patterning, and the Raman mapping showed the presence of monoclinic phase heterogeneously distributed along the patterned surfaces. An increase of the hMSC area was identified on all the microgrooved surfaces, although only the 50 µm periodicity, which is closer to the cell size, significantly favored cell elongation and alignment along the grooves. A decrease in Staphylococcus aureus adhesion was observed on the investigated micropatterns. The study suggests that linear microgrooves of 50 µm periodicity may help in promoting hMSC adhesion and alignment, while reducing bacterial cell attachment. • Nanosecond laser patterning is employed to produce periodical microgrooves on the surface of 3Y-TZP. • Interconnected microcracks, sub-micrometric pits and material pile-up are produced on the grooves after the laser treatment. • Hydrothermal degradation resistance of 3Y-TZP is decreased after the laser patterning. • Human mesenchymal stem cell spreading, elongation and alignment is enhanced on the 50 µm pattern. • Staphylococcus aureus adhesion is reduced on the patterns of low periodicity (30 and 50 µm). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the low-temperature degradation (LTD) kinetics of tetragonal zirconia with 3 mol% yttria (3Y-TZP) dental ceramic using two degradation methods: hydrothermal degradation and immersed degradation. To study transformation kinetics, we prepared 3Y-TZP powders. We pressed these powders uniaxially into a stainless mold at 100 MPa. We then sintered the compacted bodies at intervals of 50 °C between 1300 °C and 1550 °C and immersed the specimens at various temperatures from 60 °C to 80 °C in 4% acetic acid or from 110 °C to 140 °C for the hydrothermal method. We used a scanning electron microscope (SEM) to confirm crystalline grain size and used X-ray diffraction to analyze the zirconia phase. As the sintering temperature increased, the calculated crystalline grain size also increased. We confirmed this change with the SEM image. The higher sintering temperatures were associated with more phase transformation. According to the Mehl–Avrami–Johnson equation, the activation energies achieved using the hydrothermal method were 101 kJ/mol, 95 kJ/mol, and 86 kJ/mol at sintering temperatures of 1450 °C, 1500 °C, and 1550 °C, respectively. In addition, the activation energies of the specimens immersed in 4% acetic acid were 60 kJ/mol, 55 kJ/mol, 48 kJ/mol, and 35 kJ/mol, with sintered temperatures of 1400 °C, 1450 °C, 1500 °C, and 1550 °C, respectively. The results showed that a lower sintering temperature would restrain the phase transformation of zirconia because of the smaller crystalline grain size. As a result, the rate of LTD decreased. [ABSTRACT FROM AUTHOR]

Tetra pak packaging is one of the most frequently used types of packaging in the food industry. The recycling of the tetra pak packaging waste presents a difficult task because of its multi-layered, multi-component structure. In this study, the degradation of tetra pak packaging in subcritical (SubCW) and supercritical (SCW) water was investigated. The experiments were carried out in one (SCW) or two stages (SubCW and SCW), whereby the influence of the reaction temperature and time on the yield and composition of the products obtained was investigated. The maximum oil phase yield achieved in a one-stage and a two-stage degradation process was 60.7% and 65.5%, respectively. The oil and gas phases were composed of different types of hydrocarbons. Higher temperature and longer time led to higher amounts of saturated aliphatic hydrocarbons in both the oil and gas phases. The aqueous phase contained sugars (glucose, fructose) and sugar derivatives (levulinic acid, glyceraldehyde, furfurals). Based on these results, the degradation pathway of waste tetra pak packaging in SubCW and SCW was proposed. The results of the study show that the degradation of waste tetra pak packaging with SubCW and SCW is a promising recycling process.

Degrading organic soils usually become a source of increased greenhouse gas emissions and fire frequency in disturbed peatlands. As a solution, the rewetting concept should consider not only the detailed hydrological characteristics of the peatland, but should also appraise the properties of the soils. Here, we provide the results of a detailed soil study carried out on an abandoned peatland in the Kaliningrad Region, Russia. The study aims to integrate data on soil properties, hydrology, and the degree of transformation of the current soil cover in terms of how this affects spontaneous revegetation and the potential for further mire community reestablishment. The paper contributes to a greater understanding of rehabilitation patterns of disturbed peatlands depending on the soil's physical and hydrological properties in the humid climate of the southeastern Baltic region. The present-day soils of the peatland refer to two World Reference Base (WRB) groups: Gleisols and Histosols; the latter change successively from the periphery to the centre of the peatland as follows: Eutric/Sapric → Hemic → Dystric → Fibric. Most Histosols are characterised by hydrothermal degradation in the upper layers with patches of pyrogenic degradation. Some local inundated areas show environmental conditions favourable for Sphagnum growth and the formation of mire communities. We have identified six groups of sites with different ecological and time-span potentials for mire community restoration during the implementation of rewetting activities. The rewetting feasibility of the peatland's sites does not coincide with the degree of transformation of their soil profile, but is rather determined by the hydrological regime. [ABSTRACT FROM AUTHOR]

Adhesive joints are degraded when exposed to moist conditions, making it essential to assess the permeation distance of absorbed moisture. However, monitoring the water penetration in the adhesive layer is challenging because the adhesive layer is sandwiched between the adherends. To overcome this difficulty, we proposed a new monitoring system using fiber‐type near‐infrared spectroscopy (NIRS), and the moisture distribution at the joint was successfully observed by introducing quartz glass as one side of the substrate. First, the change in the absorbance spectra owing to water absorption by an epoxy adhesive was investigated by immersing epoxy‐coated aluminum alloy plates in temperature‐controlled water. It was found that the water content can be evaluated by monitoring the change in the peak intensity appearing around 1900–1950 nm. Next, water penetration into the adhesive layer sandwiched between the quartz glass and aluminum alloy was investigated by scanning the surface. The water permeation distance was found to change with temperature. Under the 23°C immersion condition, approximately 2.5 mm of water penetration was observed after 8 weeks. Because the simulation results using Fick's law of diffusion showed similar trends, it was experimentally confirmed that Fickian diffusion dominates the water distribution in the adhesive layer. [ABSTRACT FROM AUTHOR]

In this study, bionanocomposite films based on poly(lactide) (PLA) plasticised with poly(ethylene glycol) (PEG) (7.5 wt%) and reinforced with various contents of nanofibrillated cellulose (NFC) (1, 3, 5 wt%) were prepared. The hydrothermal degradation was investigated through immersion in several aqueous environments at temperatures of 8, 23, 58, and 70 °C as a function of time (7, 15, 30, 60, 90 days). The effect of water immersion on the physicochemical properties of the materials was assessed by monitoring the changes in the morphology, thermo-oxidative stability, thermal properties, and molar mass through field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The hydrothermal degradation behaviour was not critically affected regardless of the nanofibrillated cellulose content. All the materials revealed certain integrity towards water immersion and hydrolysis effects at low temperatures (8 and 23 °C). The low hydrothermal degradation may be an advantage for using these PLA biocomposites in contact with water at ambient temperatures and limited exposure times. On the other hand, immersion in water at higher temperatures above the glass transition (58 and 70 °C), leads to a drastic deterioration of the properties of these PLA-based materials, in particular to the reduction of the molar mass and the disintegration into small pieces. This hydrothermal degradation behaviour can be considered a feasible option for the waste management of PLA/PEG/NFC bionanocomposites by deposition in hot aqueous environments. [ABSTRACT FROM AUTHOR]

This study evaluates the effect of aging in artificial saliva and thermal shocks on the microhardness of the bulk-fill composite compared to the nanohybrid composite. Two commercial composites, Filtek Z550 (3M ESPE) (Z550) and Filtek Bulk-Fill (3M ESPE) (B-F), were tested. The samples were exposed to artificial saliva (AS) for one month (control group). Then, 50% of the samples from each composite were subjected to thermal cycling (temperature range: 5–55 °C, cycle time: 30 s, number of cycles: 10,000) and another 50% were put back into the laboratory incubator for another 25 months of aging in artificial saliva. The samples' microhardness was measured using the Knoop method after each stage of conditioning (after 1 month, after 10,000 thermocycles, after another 25 months of aging). The two composites in the control group differed considerably in hardness (HK = 89 for Z550, HK = 61 for B-F). After thermocycling, the microhardness decrease was for Z550 approximately 22–24% and for B-F approximately 12–15%. Hardness after 26 months of aging decreased for Z550 (approximately 3–5%) and B-F (15–17%). B-F had a significantly lower initial hardness than Z550, but it showed an approximately 10% lower relative reduction in hardness. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the low-temperature degradation (LTD) kinetics of tetragonal zirconia with 3 mol% yttria (3Y-TZP) dental ceramic using two degradation methods: hydrothermal degradation and immersed degradation. To study transformation kinetics, we prepared 3Y-TZP powders. We pressed these powders uniaxially into a stainless mold at 100 MPa. We then sintered the compacted bodies at intervals of 50 °C between 1300 °C and 1550 °C and immersed the specimens at various temperatures from 60 °C to 80 °C in 4% acetic acid or from 110 °C to 140 °C for the hydrothermal method. We used a scanning electron microscope (SEM) to confirm crystalline grain size and used X-ray diffraction to analyze the zirconia phase. As the sintering temperature increased, the calculated crystalline grain size also increased. We confirmed this change with the SEM image. The higher sintering temperatures were associated with more phase transformation. According to the Mehl–Avrami–Johnson equation, the activation energies achieved using the hydrothermal method were 101 kJ/mol, 95 kJ/mol, and 86 kJ/mol at sintering temperatures of 1450 °C, 1500 °C, and 1550 °C, respectively. In addition, the activation energies of the specimens immersed in 4% acetic acid were 60 kJ/mol, 55 kJ/mol, 48 kJ/mol, and 35 kJ/mol, with sintered temperatures of 1400 °C, 1450 °C, 1500 °C, and 1550 °C, respectively. The results showed that a lower sintering temperature would restrain the phase transformation of zirconia because of the smaller crystalline grain size. As a result, the rate of LTD decreased.

The nanostructured (8 wt%) yttria stabilized zirconia coatings (n-YSZ) were deposited by atmospheric plasma spraying (APS) to study the effect of moisture degradation on the properties of n-YSZ coatings. Variations in phase composition, microstructure and mechanical properties were comprehensively characterized. The single-edge notched beam method used for fracture toughness testing is sufficiently reliable for evaluating the integral properties of the coatings in this study. Results indicated that the microstructure of the n-YSZ coatings was significantly affected by hydrothermal degradation. Hydrothermal degradation resulted in substantial defects, such as pores and cracks, which severely decreased the mechanical properties of the n-YSZ coatings. In addition, the ceramic coat was in a state of compressive stress, and the stress initially increased and then decreased with increasing degradation time. The variations in the stress of the n-YSZ coatings are closely related to the transformation of tetragonal to monoclinic phase, which is induced by hydrothermal degradation. Additionally, several major mechanical properties of the n-YSZ coatings decreased significantly with the hydrothermal degradation, including fracture toughness from 1.28 ± 0.05 to 0.08 ± 0.01 MPa m1/2, flexural strength from 60.51 ± 2.98 to 4.54 ± 0.14 MPa, and Young's modulus from 21.98 ± 0.96 to 1.46 ± 0.33 GPa. [ABSTRACT FROM AUTHOR]

Degrading organic soils usually become a source of increased greenhouse gas emissions and fire frequency in disturbed peatlands. As a solution, the rewetting concept should consider not only the detailed hydrological characteristics of the peatland, but should also appraise the properties of the soils. Here, we provide the results of a detailed soil study carried out on an abandoned peatland in the Kaliningrad Region, Russia. The study aims to integrate data on soil properties, hydrology, and the degree of transformation of the current soil cover in terms of how this affects spontaneous revegetation and the potential for further mire community reestablishment. The paper contributes to a greater understanding of rehabilitation patterns of disturbed peatlands depending on the soil’s physical and hydrological properties in the humid climate of the southeastern Baltic region. The present-day soils of the peatland refer to two World Reference Base (WRB) groups: Gleisols and Histosols; the latter change successively from the periphery to the centre of the peatland as follows: Eutric/Sapric → Hemic → Dystric → Fibric. Most Histosols are characterised by hydrothermal degradation in the upper layers with patches of pyrogenic degradation. Some local inundated areas show environmental conditions favourable for Sphagnum growth and the formation of mire communities. We have identified six groups of sites with different ecological and time-span potentials for mire community restoration during the implementation of rewetting activities. The rewetting feasibility of the peatland’s sites does not coincide with the degree of transformation of their soil profile, but is rather determined by the hydrological regime.

Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 °C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7±0.2GPa, a fracture toughness of 7.1±0.3MPa•m1/2 and a 4-point bending strength of 940.1±67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t→m phase transformation and microcracking.

The hydrothermal degradation of different polyolefins (virgin and recycled HDPE, recycled LLDPE, metallocene LLDPE, LDPE waste, virgin and recycled PP, PP waste) and their blends in different forms (granulate, foil) was investigated with supercritical water at 450 °C. The degradation of HDPE was investigated in a time range from 15 min to 240 min. The maximum yield of the oil phase was obtained at a degradation time of 60 min and was over 90 %, therefore all further experiments were carried out at a reaction time of 60 min. It was found that the composition of the oil obtained, and its calorific value depend on the type of material degraded. The oils obtained from PE materials contained between 65.3 % and 69.5 % saturated hydrocarbons, 11.4 %–17 % olefins and 8.9 %–20 % aromatics, while the oils from PP materials contained 40.8 %–45.9 % aromatics, 28.4 %–33.4 % saturated hydrocarbons and 10.6 % to 19.2% olefins. The main compounds in the oils from PP materials were the C 9 compounds and from PE materials the C 16 compounds. An exception were the oils from rLLDPE-1-g and LDPE-b, in which C 8 compounds were most abundant and which contained the highest proportion of C 17 – C 31 hydrocarbons (approx. 17 %) compared to oils from other PE and PP materials (1.3 %–7.1 %). The HHV of the oils was between 29.4 and 45.7 MJ/kg and was highest for the oils where the gasoline/heavy oil ratio was less than 1, while the HHV of the gas phase was between 48.4 MJ/kg and 50.7 MJ/kg. [Display omitted] [ABSTRACT FROM AUTHOR]

This study evaluates the effect of aging in artificial saliva and thermal shocks on the microhardness of the bulk-fill composite compared to the nanohybrid composite. Two commercial composites, Filtek Z550 (3M ESPE) (Z550) and Filtek Bulk-Fill (3M ESPE) (B-F), were tested. The samples were exposed to artificial saliva (AS) for one month (control group). Then, 50% of the samples from each composite were subjected to thermal cycling (temperature range: 5–55 °C, cycle time: 30 s, number of cycles: 10,000) and another 50% were put back into the laboratory incubator for another 25 months of aging in artificial saliva. The samples’ microhardness was measured using the Knoop method after each stage of conditioning (after 1 month, after 10,000 thermocycles, after another 25 months of aging). The two composites in the control group differed considerably in hardness (HK = 89 for Z550, HK = 61 for B-F). After thermocycling, the microhardness decrease was for Z550 approximately 22–24% and for B-F approximately 12–15%. Hardness after 26 months of aging decreased for Z550 (approximately 3–5%) and B-F (15–17%). B-F had a significantly lower initial hardness than Z550, but it showed an approximately 10% lower relative reduction in hardness.

Single crystals of an Li‐stuffed, Al‐ and Ga‐stabilized garnet‐type solid‐state electrolyte material, Li7La3Zr2O12 (LLZO), have been analysed using single‐crystal X‐ray diffraction to determine the pristine structural state immediately after synthesis via ceramic sintering techniques. Hydrothermal treatment at 150 °C for 28 d induces a phase transition in the Al‐stabilized compound from the commonly observed cubic Iad structure to the acentric I3d subtype. LiI ions at the interstitial octahedrally (4 + 2‐fold) coordinated 48e site are most easily extracted and AlIII ions order onto the tetrahedral 12a site. Deep hydration induces a distinct depletion of LiI at this site, while the second tetrahedral site, 12b, suffers only minor LiI loss. Charge balance is maintained by the incorporation of HI, which is bonded to an O atom. Hydration of Ga‐stabilized LLZO induces similar effects, with complete depletion of LiI at the 48e site. The LiI/HI exchange not only leads to a distinct increase in the unit‐cell size, but also alters some bonding topology, which is discussed here. [ABSTRACT FROM AUTHOR]

The purpose of this research is focused on the manufacture and characterization of a partially stabilized zirconia ceramic with 3 mol% of Yttria and doped with.5 and 1.5 mol% of Nb2O5 to analyze the influence of doping, with the purpose of improving the properties before hydrothermal degradation. In the first instance, the microwave sintering process was used for the consolidation of this material, then the physical and mechanical properties were characterized. Together, the results obtained by the conventional sintering process were compared. A low hydrothermal degradation study (LTD) is presented at low temperatures in which possible changes in the mechanical properties of the ceramic materials are analyzed and its influence on the phase transformation that zirconia may present is observed. The mechanical properties were evaluated through hardness, fracture toughness, and Young's modulus tests. Likewise, their density was analyzed, and microstructure was characterized by FESEM. It was found that the microwave‐sintered samples at 1200°C exhibited superior properties of toughness than even samples sintered by conventional methods at higher temperatures (1400°C). The sample of 3Y‐TZP with 1.5 mol% Nb2O5 sintered by microwave with <.2% of porosity achieved a maximum fracture toughness value around 40% higher than the dense monolithic 3Y‐TZP material. [ABSTRACT FROM AUTHOR]

In this work, the effects of the microstructure on the hydrothermal degradation of yttria-stabilized tetragonal zirconia (Y-TZP) bioceramics and theoretical correlations of the zirconia grain size impact in simulations of body fluids were investigated. Samples of ZrO2 (3 mol.% Y2O3) powders were compacted and furtherly sintered for 4 h at different temperatures (1450, 1500, 1530 or 1600 °C), reaching nearly full density in microstructures with different grains sizes ranging from 0,35 ± 0,10 μm to 1,53 ± 0,34 µm. Tests of hydrothermal degradation were performed in autoclave (134 °C - 2 bar), varying the dwell time between 1 and 36 h. The growth of the ZrO2 grain size consistently affected the rate of degradation (represented by the transformed monoclinic m-ZrO2 content) of this ceramic: After 12 h of autoclaving, the monoclinic percentage quadrupled with an increase in the average grain size of 0.35 ± 0.1 μm to 1.53 ± 0.34μm. Using a theoretical correlation between the time of degradation in the autoclave and the respective time in the human body, it was possible to predict the content of the monoclinic phase present in the 3Y-TZP for up to 36 years of exposure in body fluids, and with that, mathematical equations that correlate grain size of ZrO2 with %monoclinic were proposed.

Tetra pak packaging is one of the most frequently used types of packaging in the food industry. The recycling of the tetra pak packaging waste presents a difficult task because of its multi-layered, multi-component structure. In this study, the degradation of tetra pak packaging in subcritical (SubCW) and supercritical (SCW) water was investigated. The experiments were carried out in one (SCW) or two stages (SubCW and SCW), whereby the influence of the reaction temperature and time on the yield and composition of the products obtained was investigated. The maximum oil phase yield achieved in a one-stage and a two-stage degradation process was 60.7% and 65.5%, respectively. The oil and gas phases were composed of different types of hydrocarbons. Higher temperature and longer time led to higher amounts of saturated aliphatic hydrocarbons in both the oil and gas phases. The aqueous phase contained sugars (glucose, fructose) and sugar derivatives (levulinic acid, glyceraldehyde, furfurals). Based on these results, the degradation pathway of waste tetra pak packaging in SubCW and SCW was proposed. The results of the study show that the degradation of waste tetra pak packaging with SubCW and SCW is a promising recycling process.

Highly reactive polyols were prepared from modified acetic acid lignin (AAL) by a two‐step combination of mild hydrothermal degradation and hydroxylation. The AAL‐based polyols became relatively reactive and compatible with diisocyanate, with a reduction in the number average molecular weight (Mn) from 2923 to 684 g/mol and an increase in the hydroxyl content from 5.21 to 9.13 mmol/g. The mechanical performance and thermal properties of the AAL‐based polyurethane elastomers (LPUEs) strongly depended on the molecular weight and hydroxyl content of the AAL‐based polyols in the partial substitution of polytetramethylethylene ether glycol (PTMEG). This study proposed the prospective utilization of AAL as an alternative resource in the synthesis of polymers and biomaterials. © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Fucoidan from Laminaria japonica is an important natural bioactive substance, and low molecular weight fucoidan (L-F) obtained by hydrothermal degradation exhibits better bioavailability. However, the anti-obesity effect of Laminaria japonica fucoidan (FUC) and whether hydrothermal degradation could enhance its activity remained uncertain. The related indicators were therefore determined and compared. According to the results, the molecular weight and glucuronic acid content of FUC were significantly reduced after degradation. Animal experiment results showed that oral administration of 300 mg/kg FUC effectively reduced body weights and serum lipid levels, while these effects of L-F were diminished. Changes in the expression levels of hepatic gene expression showed that FUC inhibited fatty acid synthesis via down-regulation expression of SREBP-1c and FAS, and promoted cholesterol consumption via up-regulation of CYP7A1 and CYP27A1. However, L-F had no significant effect on SREBP-1c and FAS. FUC and L-F also had regulatory effects on gut microbiota, but there were some differences in their specific effects. FUC improved lipid metabolism by regulating gut microbiota such as Colidextribacter , Desulfovibrio and Colidextribacter , so as to play a role in reducing body weight. L-F had weaker regulatory effect on some fat formation related microbes, which resulted in its reduced anti-obesity effect. Summarily, FUC could ameliorate obesity and improve lipid metabolism disorders, but these activities were diminished after hydrothermal treatment, which may connect with the decarboxylation of glucuronic acid and the change in regulatory activity of gut microbiota. Fucoidan from Laminaria japonica ameliorated obesity by regulating lipid metabolism, but these effects were diminished after hydrothermal treatment, which may be caused by the decarboxylation of glucuronic acid and changes in regulatory activity of gut microbiota. [Display omitted] • Fucoidan from Laminaria japonica ameliorated obesity by improving lipid metabolism. • The glucuronic acid content of fucoidan decreased after hydrothermal treatment. • Degraded fucoidan had reduced activity due to changed effects on SREBP-1c/FAS. • Degraded fucoidan had weaker regulatory effect on fat formation related microbes. [ABSTRACT FROM AUTHOR]

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Hydrothermal degradation was used to pretreat terylene with an aim of noticeably improving the yield of fermentable monomers: terephthalic acid (TPA), mono (2- hydroxyethyl) terephthalic acid (MHET), bis-hydroxyethyl terephthalate (BHET), and ethylene glycol (EG). After 0.5 h of reaction time at 180 °C, hydrothermal degradation with ammonia led to almost complete conversion of the terylene to TPA, MHET, BHET and EG, which were then transformed by Taonella mepensis WT-6 to bacterial cellulose (BC). Furthermore, the optimum fermentation conditions with the maximum BC yield were 5.0 g/L yeast extract, 30.0 °C, pH 9.0, 8.0% inoculum, and hydrolysate TOC (5.02 g/L). Additionally, mechanical and thermal analysis revealed that the properties of BC produced from TAH medium were similar to those of BC produced with HS medium. Considering the substantial amount of global terylene waste being produced, this study provides an alternative solution for the biosynthesis of BC. • A BC-producing strain was isolated from rotten ramie leaf. • Terylene ammonia hydrolysate was used as a substrate for the strain to generate BC. • Hydrothermal degradation was used to pretreat terylene waste. [ABSTRACT FROM AUTHOR]

PURPOSE. The aims of this study were to investigate mechanical properties and hydrothermal degradation behaviour of the cubic-containing translucent yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS. Four groups of Y-TZP (T, ST, XT, and P), containing different amount of cubic crystal, were examined. Specimens were aged by autoclaving at 122°C under 2 bar pressure for 8 h. Phase transformation was analyzed using X-ray diffraction (XRD) to measure phase transformation (tm). Kruskal- Wallis test was used to determine the difference. Surface hardness, biaxial flexural strength, and fracture toughness in values among the experimental groups and verified with Wilcoxon matched pairs test for hardness values and Mann Whitney U for flexural strength and fracture toughness. RESULTS. XRD analysis showed no monoclinic phase in XT and P after aging. Only Group T showed statistically significant decreases in hardness after aging. Hydrothermal aging showed a significant decrease in flexural strength and fracture toughness in group T and ST, while group XT and P showed no effect of aging on fractural strength and fracture toughness with P<.05. CONCLUSION. Hydrothermal aging caused reduction in mechanical properties such as surface hardness, biaxial flexural strength, and fracture toughness of Y-TZP zirconia. However, cubic-containing zirconia (more than 30% by volume of cubic crystal) was assumed to have high resistance to hydrothermal degradation. Clinical significance: Cubic-containing zirconia could withstand the intraoral aging condition. It could be suggested to use as a material for fabrication of esthetic dental restoration. [ABSTRACT FROM AUTHOR]

The changes in mechanical properties, hydrothermal degradation and cell adhesion were studied in 3Y-TZP under two different superficial modification patterns (uni- and multidirectional) with a surface roughness ranging from 16 to 603 nm. In this sense, mechanical properties (i.e. hardness, indentation fracture toughness and scratch) and accelerated tests in water steam were measured to evaluate the influence of the surface treatments on the superficially modified layer. Moreover, a detailed characterization through micro-Raman spectroscopy and X-Ray diffraction was performed. Finally, SaOS-2 osteoblasts were used for the evaluation of the cell adhesion behaviour on the surfaces. Overall, ground/polished specimens increased the mechanical properties and ageing resistance of mirror-like polished specimens, although resistance to degradation was maximum at intermediate conditions (S a ≈ 40−180 nm). The studied surfaces allowed cell attachment, but promoted contact guidance (i.e. cell alignment) only on unidirectionally ground surfaces above Sa = 150 nm. [ABSTRACT FROM AUTHOR]

The degradation behavior in high pressure water of UN and UN + (5–10 w%) UO 2 monolithic pellets fabricated from UN synthesized via a hydride-dehydride-nitride thermal process was investigated. Sintered pellets (>90% theoretical density) were subjected to hydrothermal oxidation in a water-filled static autoclave at temperatures ranging from 250 to 350 °C and pressures to 16.5 MPa. Phase characterization and microstructural and chemical analysis was performed on the resulting corrosion products using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The results of this screening study show that grain boundary attack and spallation is the primary degradation mechanism in hydrothermal oxidation conditions. The results also suggest the corrosion rate is higher in UN and UN-UO 2 with higher starting oxygen content. • UN and UN-UO 2 composite pellets were subjected to hydrothermal autoclave testing at 250–350 °C. • Formation of reaction products along grain boundaries results in volume expansion leading to breakdown of monolithic pellets. • Increased oxygen impurities in the UN powder, and additional UO 2 in the composites, appears to enhance oxidation behavior. [ABSTRACT FROM AUTHOR]

Abstract Self-reinforced polymer composites (SRCs) are proposed as a suitable alternative for composite development, based in the combination of a polymeric matrix and a polymeric fibre made of the same polymer. SRCs based in polylactide (PLA) could be fully biodegradable and their valorisation routes could presumably be assimilated to those for neat PLA. In this sense, the aim of this study was to develop new self-reinforced PLA-based composites and ascertain their biodegradability. For this purpose, PLA-based SRCs were obtained through a thermo-compression procedure and their biodegradability corroborated under standard conditions (ISO 20200). Moreover, a deep study of the effect of the different factors involved in the biodegradation of the composites such as the temperature, the water and the compost medium was considered relevant to delimitate the long-term properties and valorisation routes for these materials. The macroscopic and microscopic appearance as well as the thermo-oxidative stability, the thermal properties and the molar mass were evaluated. Although degradation was perceived due to the effect of temperature, the synergistic combination of water and temperature ‒and compost‒ was found to play a key role in the biodegradation of these materials. Overall, these SRCs can be considered as promising candidates, since their end-of-life management options can be guaranteed under standardised composting conditions. Highlights • PLA-based self-reinforced polymer composites (SRCs) were successfully developed. • The biodegradability of the PLA-based SRCs was corroborated under standardised conditions (ISO 20200). • The combination of water and temperature ‒and compost‒ was found to play a key role in the biodegradation of these materials. • PLA-based SRCs wastes could be managed and valorised under the same standard composting conditions as PLA. [ABSTRACT FROM AUTHOR]

The effect of hydrothermal conditions on enzymatic hydrolysis lignin (EHL) degradation in water-isopropyl alcohol co-solvent and optimal conditions were investigated. The yields and reactivity toward formaldehyde of degraded enzymatic hydrolysis lignin (DEL) were determined. The optimal conditions of temperature, time, and ratio of solids to liquids were 250 °C, 60 min, and 1:10 (w/v), respectively. The EHL and DEL were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), thermal gravity (TG), and differential scanning calorimetry (DSC) analyses. The results revealed that the molecular weight and polydispersity of DEL were lower than that of EHL. Although the fundamental structure of lignin before and after hydrothermal degradation was retained, the ether (β-O-4, α-O-4, etc.) content decreased, while that of hydroxyl (phenolic and aliphatic) increased. The DTGmax and Tg values shifted from 334 and 117 °C to 304 and 105 °C, respectively.

Abstract This study aimed to investigate slow crack growth (SCG) behavior of a zirconia ceramic after grinding and simulated aging with low-temperature degradation (LTD). Complementary analysis of hardness, surface topography, crystalline phase transformation, and roughness were also measured. Disc-shaped specimens (15 mm Ø × 1.2 mm thick, n = 42) of a full-contour Y-TZP ceramic (Zirlux FC, Amherst) were manufactured according to ISO:6872-2008, and then divided into: Ctrl – as-sintered condition; Ctrl LTD – as-sintered after aging in autoclave (134°C, 2 bar, 20 h); G – ground with coarse diamond bur (grit size 181 μm); G LTD – ground and aged. The SCG parameters were measured by a dynamic biaxial flexural test, which determines the tensile stress versus stress rate under four different rates: 100, 10, 1 and 0.1 MPa/s. LTD led to m-phase content increase, as well as grinding (m-phase content: Ctrl – 0%; G – 12.3%; G LTD – 59.9%; Ctrl LTD – 81%). Surface topography and roughness analyses showed that grinding created an irregular surface (increased roughness) and aging did not promote any relevant surface change. There was no statistical difference on surface hardness among different conditions. The control group presented the lowest strength values in all tested rates. Regarding SCG, ground conditions were less susceptible to SCG, delaying its occurrence. Aging (LTD) caused an increase in SCG susceptibility for the as-sintered condition (i.e. G < G LTD < Ctrl < Ctrl LTD).

Objectives The dental market moves towards high-translucency monolithic zirconia dental crowns, which are usually placed either with – or without – a thin glaze layer. The microstructural features and the mechanical performances of these materials are still controversial, as well as their susceptibility to aging. This paper aims at studying these aspects in the current generation of zirconia dental crowns showing different degrees of translucency. Methods Four different commercial zirconia materials were investigated, including one standard ‘full-strength’ 3Y-TZP and three grades with improved translucency. The microstructural features (phase composition and assemblage, grain size) were carefully studied, as well as mechanical properties (biaxial bending strength and indentation toughness), translucency and aging behavior (in autoclave at 134 °C). Aging was conducted on crowns with and without glaze to better represent clinical uses. Results Important differences are found in terms of microstructures among the materials in terms of cubic phase content and yttria in the tetragonal phase, leading to different optical, mechanical and aging resistance properties. We show that higher cubic phase content leads to better translucency and stability in water steam, but at the expense of strength and toughness. A compromise is always inevitable between translucency and aging resistance on one side and mechanical properties on the other side. Significance - Even so called ‘high translucent’ zirconia ceramics tested in this work should be considered as medium translucency materials. - Aging occurs in standard state-of-the-art dental zirconia and glazing does not fully avoid this issue. However, aging did not compromise strength even after prolonged duration. - Aging is null in the ‘highly translucent’ zirconia grades but at the expense of strength, which is then comparable to glass-ceramics. [ABSTRACT FROM AUTHOR]

This study aimed to investigate slow crack growth (SCG) behavior of a zirconia ceramic after grinding and simulated aging with low-temperature degradation (LTD). Complementary analysis of hardness, surface topography, crystalline phase transformation, and roughness were also measured. Disc-shaped specimens (15 mm Ø × 1.2 mm thick, n = 42) of a full-contour Y-TZP ceramic (Zirlux FC, Amherst) were manufactured according to ISO:6872-2008, and then divided into: Ctrl - as-sintered condition; Ctrl LTD - as-sintered after aging in autoclave (134°C, 2 bar, 20 h); G - ground with coarse diamond bur (grit size 181 µm); G LTD - ground and aged. The SCG parameters were measured by a dynamic biaxial flexural test, which determines the tensile stress versus stress rate under four different rates: 100, 10, 1 and 0.1 MPa/s. LTD led to m-phase content increase, as well as grinding (m-phase content: Ctrl - 0%; G - 12.3%; G LTD - 59.9%; Ctrl LTD - 81%). Surface topography and roughness analyses showed that grinding created an irregular surface (increased roughness) and aging did not promote any relevant surface change. There was no statistical difference on surface hardness among different conditions. The control group presented the lowest strength values in all tested rates. Regarding SCG, ground conditions were less susceptible to SCG, delaying its occurrence. Aging (LTD) caused an increase in SCG susceptibility for the as-sintered condition (i.e. G < G LTD < Ctrl < Ctrl LTD). [ABSTRACT FROM AUTHOR]

Bio-oils rich in monoaromatic phenolic compounds were produced by a hydrothermal treatment in a batch reactor from organosolv lignin derived from beech wood. Reaction temperatures and times were varied (270–350 °C and 10–120 min, respectively). Increase in the temperature at a particular reaction time had a positive impact on the bio-oil yields, which varied from 8.0 wt% to 14.6 wt%, based on the original amount of dry lignin. GC–MS analysis of bio-oils revealed that the yields of monoaromatic compounds ranged from 22 to 65 wt% of bio-oil depending on the reaction conditions. Syringol (8.9–22.8 wt% of bio-oil), guaiacol (2.6–9.3 wt% of bio-oil), pyrocatechol (0–12.4 wt% of bio-oil), 3-methoxycatechol (0–21 wt% of bio-oil), 4-methylsyringol (0.5–5.9 wt% of bio-oil), and syringaldehyde (0–9 wt% of bio-oil) were identified as the major aromatic compounds. In addition to bio-oil, gaseous components, water solubles, char, and undegraded lignin were formed in the experiments. The mass balances of the experiments were constructed. The results show that monoaromatics can be produced at a moderate yield through uncatalysed lignin hydrothermolysis; char formation remains as an obstacle, however, and its prevention calls for the usage of catalysts and/or organic solvents. [ABSTRACT FROM AUTHOR]

Abstract: 5‐Hydroxymethylfurfural (5‐HMF) is one of the most important platform chemicals in biorefinery, which could be further converted into bio‐fuels. In this work, an effective and green route for 5‐HMF production from chitosan biomass in a dimethylsulfoxide (DMSO)/water mixed solvent using acidic ionic liquids as the catalysts is reported. Several ionic liquids were successfully synthesized and used as catalysts for the degradation of chitosan. Benzimidazolium chloride ([Hbim]Cl) exhibited the best catalytic activity. We achieved a maximum 5‐HMF yield of 34.9 mol% in 10 wt% DMSO‐water mixed solvent. Moreover, the catalyst could be easily recycled and reused at least five times without a significant loss of activity. Our investigation involved the use of recycled catalysts and crustacean waste as the starting material, which makes the process “green” and sustainable. [ABSTRACT FROM AUTHOR]

Carbonaceous solid acid (CSA) catalysts with –SO3H, –COOH, and phenolic –OH functional groups were prepared by hydrothermal carbonization and sulfuric acid impregnation methods. A maximum furfural (FF) yield of 19.66% from corncob degradation remained stable at 10 runs at 180°C for 170 min while the concentration of sulfuric acid was employed from 2.0 to 0.5 mol/L. The sulfur in CSA catalyst exists in two forms, namely SO42−and –SO3H. The free sulfuric acid and carbon together with –SO3H created good physical contact between the lignocellulose substrate and the solid catalyst in the reaction, and drastically improved the depolymerization rate of hemicelluloses and cellulose to soluble polysaccharide. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effects of grinding and low temperature aging on the biaxial flexural strength, structural reliability (Weibull analysis), surface topography, roughness analysis, and phase transformation (t→m) of an yttrium-stabilized tetragonal zirconia polycrystalline ceramic. Ceramic discs (15.0×1.2±0.2 mm, VITA In-Ceram YZ) were prepared and randomly assigned into six groups according to 2 factors (n=30): ‘grinding’ (Ctrl – without treatment, as-sintered; Xfine – grinding with extra fine diamond bur – 30 µm; Coarse – grinding by coarse diamond bur – 151 µm), and ‘aging’ (without or with aging: Ctrl LTD ; Xfine LTD ; Coarse LTD ). Grinding was performed in an oscillatory motion with a contra-angle handpiece under constant water-cooling. Low temperature degradation (LTD) was simulated in an autoclave at 134 °C, under 2 bar pressure, for 20 h. The roughness (R a and R z parameters) significantly increased after grinding in accordance with bur grit-size (Coarse>Xfine>Ctrl), and aging promoted distinct effects (Ctrl=Ctrl LTD ; Xfine>Xfine LTD ; Coarse=Coarse LTD ). Grinding increased the m-phase, and aging led to an increase in the m-phase in all groups. However, different susceptibilities to LTD were observed. Weibull analysis showed a significant increase in the characteristic strength after grinding (Coarse=Xfine>Ctrl), while aging did not lead to any deleterious impact. Neither grinding nor aging resulted in any deleterious impact on material reliability (no statistical decrease in the Weibull moduli). Thus, neither grinding nor aging led to a deleterious effect on the mechanical properties of the evaluated Y-TZP ceramic although a high m-phase content and roughness were observed. [ABSTRACT FROM AUTHOR]

This paper presented a novel process for production of furfural by hydrothermal degradation of corncob over biochar catalyst, in which it was prepared with the recycling degradation solution and lignocellulosic solid residues. The biochar catalyst was papered by lignocellulose residues and concentrated saccharide solution, and then impregnated in 0.5 mol/L sulphuric acid at room temperature for 24 h assisted by the ultrasonic vibration. In the system of recycling, 8.8 % lignocellulose residues and 100 % concentrated saccharide solution from corncob hydrolysis have been recycled. Hydrolysis of corncob was carried out at 180 °C for duration of 170 min over the biochar catalyst. The experimental results have shown that the furfural yield of up to 37.75 % and overall corncob conversion rate of 62.00 % could be achieved under optimum operating conditions for the catalysts preparation and the corncob hydrolysis. It is believed that the acid density of 4.27 mmol/g of biochar catalyst makes the SOH groups cleave β-1,4 glycosidic linkages effectively and hydrolyze the cellulose and hemicellulose to water-soluble sugars, as well as to facilitate dehydration of xylose to give the product of furfural. [ABSTRACT FROM AUTHOR]

Recycled natural materials such as silk fabric have attracted more and more public attention over the past few years. In this research, unsaturated polyester resin was used as matrix, glass mat and silk fabric were employed as reinforcement to fabricate the laminated hybrid composites by hand lay-up method. Three-point flexural quasi-static and load-controlled low cycle bending fatigue (LCBF) tests at 55 %, 70 % and 85 % pre-set load levels were performed. The composite specimens were also subjected to hot water immersion treatment at 80 oC for different durations. The effects of the immersion treatment on the bending and impact fracture characteristics were investigated. The results showed that higher flexural modulus and strength were obtained when silk fabric layer was stacked at the middle layer. It seems that the antifatigue property was improved by the inclusion of silk fabric reinforced in glass mat hybrid composites. In the water immersion experiments, both the flexural properties and impact properties were improved initially until reaching the maximum and then decreased continuously with further increase in exposure time. These seemingly contradictory behaviors are due to relaxation of the internal stress, swelling of the silk fibers and the weakening of fiber/matrix interface. [ABSTRACT FROM AUTHOR]

The aim of this study was to systematically review the literature to assess if low-temperature degradation (LTD) simulation in autoclave promotes deleterious impact on the mechanical properties and superficial characteristics of Y-TZP ceramics compared to the non-aged protocol. The MEDLINE via PubMed electronic database was searched with included peer-reviewed publications in English language and with no publication year limit. From 413 potentially eligible studies, 49 were selected for full-text analysis, 19 were included in the systematic review with 12 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Statistical analysis was performed using RevMan 5.1, with random effects model, at a significance level of p <0.05. Descriptive analysis of monoclinic phase content data showed that aging in autoclave promotes an increase in m-phase content (ranging from 0% up to 13.4% before and 2.13% up to 81.4% after aging) with intensity associated to the material susceptibility and to the aging parameters (time, pressure and temperature). Risk of bias analysis showed that only 1 study presented high risk, while the majority showed medium risk. Five meta-analyzes (factor: aging×control) were performed considering global and subgroups analyzes (pressure, time, temperature and m-phase % content) for flexural strength data. In the global analysis a significant difference ( p <0.05) was observed between conditions, favoring non-aging group. Subgroup analysis revealed statistical difference ( p <0.05) favoring non-aging, for aging time >20 h. However, for shorter aging times (≤20 h), there was no difference between groups. Pressure subgroup analysis presented a statistical difference ( p <0.05) only when a pressure ≥2 bar was employed, favoring non-aging group. Temperature subgroup analysis showed a statistical difference ( p <0.05) only when temperature=134 °C was used, favoring the non-aging group. M-phase % content analysis presented statistical difference ( p <0.05) when more than 50% of m-phase content was observed, favoring non-aging group. High heterogeneity was found in some comparisons. Aging in autoclave promoted low-temperature degradation, impacting deleteriously on mechanical properties of Y-TZP ceramics. However, the effect of LTD depends on some methodological parameters indicating that aging time higher than 20 h; pressure ≥2 bar and temperature of 134 °C are ideal parameters to promote LTD effects, and that those effect are only observed when more than 50% m-phase content is observed. [ABSTRACT FROM AUTHOR]

Ceramic composites based on (Ce, Y)-TZP/Al 2 O 3 system have great potential for applications as dental implants due to their unusually great balance between good mechanical properties and resistance to hydrothermal degradation. Surface roughness plays an important role in controlling these properties, but few studies have investigated the relationship between cytocompatibility and surface roughness, at levels considered moderate and low, comparable to titanium implants. In this work, bending strength, hydrothermal degradation and biological evaluation of a ceramic composite based on (Ce,Y)-TZP/Al 2 O 3 system were investigated as a function of surface roughness. Compacted samples were sintered at 1500 °C - 2h and then submitted to different surface treatments: Group 1 composed of samples with smooth surfaces, Group 2 and Group 3 composed of rough surfaces (grinded with 15 μm or 45 μm diamond sandpaper, respectively. Samples were characterized by X-ray diffraction, scanning electron microscopy, contact angle and optical profilometry and then subjected to hydrothermal degradation tests in autoclave (134 °C - 2 bar) using artificial saliva. The Piston-on-three-balls (P–3B) testing was used to determine flexural strength. To assess indirect cytotoxicity, samples were immersed in the culture medium for NIH-3T3 cells for 72 h. Furthermore, cell adhesion and proliferation were investigated using MG63 cells (human osteosarcoma) after 3, 7, 14, and 21 days of culture. Cytotoxicity, adhesion, and cell proliferation were examined by the Methyl Tetrazolium salt (MTS) and Alizarin Red, using a confocal laser microscope. The results indicated that the materials have high resistance to degradation. Furthermore, the (Ce,Y)-TZP/Al 2 O 3 composites are not cytotoxic. The flexural strength of the composites was 913 ± 103 MPa in samples presenting original (smooth) surface, however, a reduction in the order of 17% was observed in samples containing rough surfaces. The rougher samples show the best cellular adhesion and proliferation, leading to the formation of a mineralized matrix after 21 days. These results clearly suggest that the new (Ce,Y)-TZP/Al 2 O 3 brand is strong and highly biocompatible and warrants further study. [ABSTRACT FROM AUTHOR]

The main aim of this study was to evaluate pressurized hot water as a green and environmentally friendly extraction medium for the isolation of phenolic compounds from larch waste wood. Such isolates could find applications in the food, feed, pharmaceutical and cosmetics industries or as natural ingredients for adhesives or biocidal coatings in the wood industry. In the first step different larch wood fractions were extracted using batch system aiming to determine the most suitable fraction for isolation. The content of extractives, total phenolic and tannin content of obtained extracts and their antioxidant activity were evaluated. Secondly, semi-continuous operation was applied, where effects of temperature, addition of ethanol and flow rate were studied. Extraction yield was monitored and extracts were again analyzed for their total phenolic content and antioxidant activity. HPLC analysis was performed, in order to study the effect of temperature and addition of ethanol on the hydrothermal degradation of phenolics during semi-continuous operation. Finally, the economics of pilot-scale and industrial-scale processes with different extractor capacities, ranging from approximately 12 to 1200 kg of woody material per day and operating at optimal conditions for isolation of larch wood extractives was evaluated, in order to determine the cost of manufacturing of such a product. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this study, the hydrothermal degradation of fats, carbohydrates and proteins in sunflower seeds after treatment with subcritical water was observed. Sunflower seeds were subjected to subcritical water in a wide temperature range (130-240 °C) for periods from 5 to 120 minutes. The oil- and water-soluble phases were analysed for products of hydrothermal degradation. Oil stability was investigated by analysing the content of free fatty acids using gas chromatography. The water-soluble phase was analysed for the presence of any formed amino acids, and the amount of carbohydrates remaining after treatment was determined. Total amino acids and carbohydrates were determined using the ninhydrin and phenol/sulphuric acid spectrophotometric methods, respectively. The results show that oils are the most stable macronutrient present in sunflower seeds. Only small amounts of free fatty acids had formed during processing but the amount drastically started to increase at 240 °C. Proteins seem to be less stable than oils, whereas carbohydrates have proven to be very susceptible to hydrothermal degradation. [ABSTRACT FROM AUTHOR]

In the present study, 8YSZ:Eu 3+ powder was synthesized using co-precipitation route. The evolution of phase composition and fluorescence properties of 8YSZ:Eu 3+ powder have been assessed after being subjected to hydrothermal degradation for different times. Morphology and microstructure of the sintered powder were observed by transmission electron microscope (TEM) and scanning electron microscope (SEM). XRD, Raman spectra, photoluminescence (PL) spectra and the decay curve were used to evaluate the phase composition variation and fluorescence properties variation of the powder. The results showed that 8YSZ:Eu 3+ powder had a pure tetragonal phase structure. Under hydrothermal degradation conditions, due to the reaction of OH − and oxygen vacancy, the transformation of tetragonal to monoclinic occurred, furthermore the fluorescence properties of the powder were altered. [ABSTRACT FROM AUTHOR]