Hydroxyl Content Research Articles

Revealing Mechanisms of an Eco-Friendly GaN Electrochemical Mechanical Removal Process Modified with Green Fenton Reaction.

Gallium Nitride (GaN), a leading third-generation semiconductor material, offers exceptional properties and broad application potential. However, its high hardness and chemical inertness make GaN wafers difficult to process, posing significant challenges in improving the polishing efficiency. During the electrochemical mechanical polishing (ECMP) process, the oxidation effect on the GaN surface critically affects the material removal rate (MRR). While various methods have been developed to enhance the concentration of hydroxyl radicals (OH*) to improve the process, their instability and rapid decomposition present further obstacles to maintaining concentration and stability. The present study proposed a novel approach using sodium tripolyphosphate (STPP) as an electrolyte additive for ECMP under a green Fenton reaction. Furthermore, the MRR and surface roughness (Ra) of GaN-ECMP were comprehensively evaluated. Atomic force microscopy (AFM) was used to observe the surface morphologies of GaN wafers after ECMP. Energy-dispersive spectrometry (EDS) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the generated oxide layers. The nanoscratch tests were conducted to reveal the material removal mechanisms of GaN under the synergistic effect of STPP and Fe2+. The results indicated that an efficient GaN-ECMP process (MRR > 800 nm/h) with good surface quality (Ra < 0.33 nm) can be realized by employing STPP as electrolyte additives. This study breaks the limitation of iron precipitate formation in the ECMP slurries during the Fenton reaction. It extends the lifetime of the hydroxyl radicals (OH*) produced by the Fenton reaction, which presents a beneficial exploration of seeking an eco-friendly polishing slurry for GaN-ECMP.

Different effects of polyphenols on hydration, pasting and rheological properties of rice starch under extrusion condition: From the alterations in starch structure.

Effects of polyphenols including caffeic acid (CA), ferulic acid (FA), epigallocatechin gallate (EG), tannic acid (TA) and resveratrol (R) on physicochemical and structural properties of rice starch (RS) under the extrusion condition were investigated. Extrusion altered the hydration, pasting and rheological properties of rice starch. Adding FA exhibited the best improvement effect on hydration properties of extruded rice starch (E-RS). All polyphenols possessed different inhibitory effects on short-term retrogradation of E-RS following the order of TA>EG>CA>FA>R. The FA and CA enhanced the viscoelasticity of E-RS, whereas the other polyphenols had opposite influences. Polyphenols mainly interacted with starch via hydrogen bonds, which transformed the crystalline structure to V-type and increased the molecular weight of E-RS. Above different effects were due to polyphenols exhibited varied microstructure and phenolic hydroxyl group content. These findings provided valuable information for preparing extruded starchy foods rich in polyphenols.

Effect of pretreatment temperature and atmosphere on the structure and adsorption properties of KOH-activated porous carbon for methylene blue removal

The synthesis and exploration of the properties of activated porous carbons – materials capable of capture of substances – increasingly attracts the attention of researchers nowadays. However, studies generally focus on absolute values of adsorption (or other) properties. Pretreatment of carbonaceous materials, whether at high or low temperatures, plays a key role in generating the precursor structure that is subsequently activated. Our research addresses a gap in the existing literature by exploring how pretreatment conditions influence the properties of activated carbon. For the first time, we show how both the pretreatment atmosphere (inert or air) and the temperature used affect the final structure and adsorption performance of polyacrylonitrile-based activated carbons. We found that as the pretreatment temperature increases, the specific surface area decreases, and the crystallite size grows. The sample without any pretreatment showed the largest surface area of 2298.3 m2/g and the best adsorption capacity for methylene blue, reaching 508.4 mg/g. However, it also possesses the lowest nitrogen content, affecting its suitability for certain applications. Additionally, pretreatment atmosphere influences surface characteristics, with inert pretreatment resulting in higher hydroxyl group concentration compared to air pretreatment. This difference in hydroxyl groups contributed to varied adsorption values, measuring 441.2 and 422.6 mg/g for the inert and air pretreated samples, respectively. This highlights the importance of both pretreatment temperature and atmosphere in tailoring the properties of activated carbons for diverse applications.

Bioactive lignin from maleic acid hydrotropic fractionation: Revealing the structural-bioactivity relationship.

Lignin possesses diverse bioactivities due to its unique physicochemical structure. This study investigates the structural-bioactivity relationships of lignin derived from maleic acid hydrotropic fractionation (MAHF) of two types of herbaceous biomass. The results indicated that lignin with higher phenolic hydroxyl (-OH) content (up to 2.0 mmol/g) and carboxyl (-COOH) groups (up to 0.89 mmol/g) exhibited significantly enhanced antioxidant activity. The highest antioxidant of MAHF lignin (MAHL) reached 98 % for scavenging DPPH (2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl) at 0.56 mg/mL. Antibacterial tests revealed that MAHLs demonstrated inhibition rates of 66 % against E. coli and 54 % against S. aureus at 10 mg/mL. MAHLs at 1 mg/mL concentration blocked >98 % of UV radiation. Furthermore, the study demonstrated that lignin with higher phenolic hydroxyl (-OH), carboxyl (-COOH), and syringyl (S) units and conjugated double bonds exhibit enhanced bioactive properties. Lignin with lower Mw and PDI also tends to possess good bioactivities. The findings from the study can facilitate the application of lignin as an efficient, cost-effective, and renewable biopolymer additive in various industries.

Nanoconfinement‐Enabled Resistance to Water Matrix Components for Selective Degradation of Micropollutants

AbstractDespite recent substantial advances in water treatment, the ability to selectively degrade trace micropollutants in real waters with complex matrix components remains a grand challenge. Here we report rational crafting of graphene oxide (GO)‐wrapped defective TiO2 composite catalysts that creates nanoscopic confinement over the TiO2 surface within GO, thereby enabling the selective degradation of micropollutants through effectively excluding natural organic matter (NOM) and anions from the nanoconfined catalytic sites. In contrast to unconfined counterparts, the nanoconfined composite catalysts retain high degradation efficiency when exposed to various concentrations of NOM and anions, even in real water samples. Oxygen vacancies in TiO2 promote electron separation and oxygen adsorption, leading to a 4.9‐fold increase in hydroxyl radical concentration within the nanoconfined space compared to the bulk solution. In situ X‐ray photoemission spectroscopy and Raman spectroscopy unveil the nanoconfined catalytic sites on the TiO2 surface, where micropollutants smaller than the pores of GO are effectively degraded, while NOM with a larger size is excluded by GO. Furthermore, the formation of toxic disinfection byproducts is well controlled due to the exclusion of NOM. This work provides a simple yet viable strategy for designing 2D material‐wrapped catalysts to selectively degrade target micropollutants in complex real waters.

Green Manufacture of Hydrated Polymers Coatings with On-Demand Mechanics and Lubricity Based on Novel Biobased Polymerizable Deep Eutectic Solvents.

The aging population necessitates a critical need for medical devices, where polymers-based surface lubrication coating is essential for optimal functionality. In fact, lubrication and mechanical requirements vary depending on the service environment of different medical devices. Until now, key mean is still blank for general preparation of hydrophilic polymers-based lubrication coatings with on-demand mechanics and lubricity. This study introduces a novel hydrophilic lubrication coating with tunable mechanical properties and lubricity, derived from eco-friendly polymerizable deep eutectic solvents (PDESs) containing betaine, hydroxyethyl acrylate, glycerol, and tannic acid. Unlike traditional high molecular weight polymers, this approach leverages small-molecule, high-biobased PDESs, thereby simplifying the synthesis process. The resulting coating demonstrates exceptional adhesion to a range of medical device materials─including glass, stainless steel, polyvinyl chloride, and polyurethane─thanks to the high content of hydroxyl groups and pyrogallol motifs from tannic acid. It also enables the precise tuning of mechanical strength, modulus, adhesion, hydrophilicity, and lubrication properties by varying the amounts of glycerol and tannic acid. Furthermore, the coating undergoes a hydration-induced transition from high-strength, high-friction to low-strength, low-friction states, maintaining repeatable performance. Additionally, the synergistic effects of betaine and tannic acid in the PDES contribute to its notable antimicrobial properties. In summary, these PDESs demonstrate significant potential for enhancing lubrication in a range of biomedical devices.

Stimuli-Chromic Oxazolidine Latex Nanoparticles for Dual-Responsive pH-Sensors and Rewritable Halochromic Papers: A Physicochemical Study on Colorimetric and Fluorimetric Signals.

Oxazolidine is a new category of stimuli-chromic compounds that has unique intelligent behaviors such as halochromism, hydrochromism, solvatochromism, and ionochromism, all of which have potential applications for designing and constructing chemosensors by using functionalized-polymer nanocarriers. Here, the poly(MMA-co-HEMA) based nanoparticles were synthesized by emulsion copolymerizing methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) in different copolymer compositions. The poly(MMA-co-HEMA) based nanoparticles were modified physically with tertiary amine-functionalized oxazolidine (as an intelligent pH-responsive organic dye) to prepare halochromic latex nanoparticles. Investigation of optical properties including absorbance and emission by spectroscopic methods indicates that the halochromic behavior of the oxazolidine in nanoparticles is influenced significantly by the particle size, morphology, and concentration of hydroxyl groups. To develop optical chemosensors for the detection of pH, the pH-responsivity of halochromic latex nanoparticles in aqueous solutions with different pHs in the wide range of 1-14 were studied by UV-vis and fluorescence spectroscopies, and these results confirmed the successful photodetection of pH in a fast and facile manner. The investigation of the solid-state optical properties and pH-responsivity of halochromic nanoparticles by impregnation of latex-coated cellulosic papers with solutions having different pHs indicates the halochromic nanoparticles maintained their optical properties after incorporation to cellulose matrix and displayed notable colorimetric and fluorimetric pH-responsivity. Hence, the paper-based pH-sensors were prepared from halochromic papers and the investigation of their pH-responsivities showed the halochromic papers constructed from halochromic nanoparticles with HEMA concentration above 20 wt % have the best pH-responsivity with high resolution, high contrast, and high-intensity color change and fluorescence emission change. In addition, the halochromic papers were used as rewritable hydrochromic papers for hand-writing and stamp-printing by using acid and base solutions as inks, in which papers based on halochromic nanoparticles with a HEMA concentration above 20 wt % have maximum printability, resolution, and intensity. This study proposed the significant effects of polarity and concentration of functional groups on the halochromic properties of oxazolidine molecules and the unique role of functionalized polymer nanoparticles as a carrier of oxazolidine for its protection toward environmental degradations. These parameters should be considered in future studies on the development of halochromic papers for intelligent pH-sensor and rewritable papers.

A ternary deep eutectic solvent for efficient biomass fractionation and lignin stabilization.

The efficient isolation and lignin stabilization are critical to the fractionation process of lignocellulosic biomass, enabling the subsequent valorization of both carbohydrates and lignin. In this study, a ternary deep eutectic solvent pretreatment system with outstanding reusability has been developed. Under optimal conditions (ChCl: MT: p-TsOH=1:1:0.5, 120°C, 60min), the system efficiently removed 94.66% of hemicellulose and 95.74% of lignin while retaining 84.50% of cellulose. Glucose was obtained from the cellulose-rich solid residue via enzymatic hydrolysis, achieving an 87.12% yield. This DES system inhibits lignin condensation through a dual mechanism of α-etherification and intermolecular forces (π-π stacking and hydrophobic interaction). The recovered lignin exhibits a low molecular weight (922-1049g/mol), high phenolic hydroxyl content (2.57-3.37mmol/g), low polydispersity (1.54-1.61), and high purity (93.02%). Combined with its superior antioxidant activity and UV shielding properties, this lignin represents a promising new resource with potential applications.

The Effect of Different Sulphur Sources Applied at Various Rates on Soil pH

Soil pH, governed by the relative concentrations of hydrogen () and hydroxyl () ions, is a key factor affecting the chemical, physical, and biological properties of soils. Most soils in Türkiye are alkaline due to calcareous parent material and climatic influences, which restricts the availability of essential nutrients to plants. Sulphur applications are widely employed to reduce soil pH and increase nutrient bioavailability. The use of Sulphur for the amelioration of alkaline soils will continue to be a crucial strategy for enhancing agricultural sustainability in the future. This study investigates the effects of different Sulphur sources on the pH of sandy and clay-loam texture soils. This study investigates the effects of different Sulphur sources on the pH of sandy and clay loam textured soils. The soil samples used in the research were taken from Pınarbaşı and Melikgazi districts of Kayseri province, and soil samples were taken from both regions from a depth of 30 cm and from 20 randomly determined different points. Sulphur applications were applied at rates of (0, 0.02, 0.04 g 100 g-1) (X: powdered Sulphur ) and (0, 0.044, 0.088 g 100 g-1) (Y: granular Sulphur ) based on weight for clay-loam and sandy textured soils, respectively. Samples taken on days 0, 15, 30, 60, 90, 180, and 360 post-applications showed that the impact of Sulphur applications on soil pH change was significant across all treatments (p&lt;0.01). The lowest pH measurement, 6.92, was observed in sandy textured soils with an application from granular Sulphur at 0.088 g 100 g-1. The pH change in clay-loam textured soils was found to range from 8.13 to 7.79, and in sandy textured soils from 7.69 to 6.92. These changes suggest that the acidifying effect of Sulphur oxidation on soil pH varies depending on the soil’s buffering capacity, particle size ratio, application rate, and incubation day. Consequently, the granular Sulphur was found to be more effective compared to the control and powdered Sulphur , and an application rate of 0.088 g 100 g-1 might be effective for both clay-loam and sandy soils. However, due to its lack of economic feasibility, 0.044 g dose or the doses from powdered Sulphur might be more appropriate.

Nanoconfinement-Enabled Resistance to Water Matrix Components for Selective Degradation of Micropollutants.

Despite recent substantial advances in water treatment, the ability to selectively degrade trace micropollutants in real waters with complex matrix components remains a grand challenge. Here we report rational crafting of graphene oxide (GO)-wrapped defective TiO2 composite catalysts that creates nanoscopic confinement over the TiO2 surface within GO, thereby enabling the selective degradation of micropollutants through effectively excluding natural organic matter (NOM) and anions from the nanoconfined catalytic sites. In contrast to unconfined counterparts, the nanoconfined composite catalysts retain high degradation efficiency when exposed to various concentrations of NOM and anions, even in real water samples. Oxygen vacancies in TiO2 promote electron separation and oxygen adsorption, leading to a 4.9-fold increase in hydroxyl radical concentration within the nanoconfined space compared to the bulk solution. In-situ X-ray photoemission spectroscopy and Raman spectroscopy unveil the nanoconfined catalytic sites on the TiO2 surface, where micropollutants smaller than the pores of GO are effectively degraded, while NOM with a larger size is excluded by GO. Furthermore, the formation of toxic disinfection byproducts is well controlled due to the exclusion of NOM. This work provides a simple yet viable strategy for designing 2D material-wrapped catalysts to selectively degrade target micropollutants in complex real waters.

Hydrous Asthenosphere Underneath the Northern Pannonian Basin

ABSTRACTThis study reveals the structural hydroxyl content in clinopyroxenes of three cumulate xenoliths from the Nógrád‐Gömör/Novohrad‐Gemer Volcanic Field (northern Pannonian Basin), with values ranging from 275 to 384 ppm. Based on these data, the water content of the equilibrium parental alkali basaltic melt was estimated to be between 1.5 and 2.1 wt.%, which aligns well with values for alkali basalts worldwide. The mantle source water content was also calculated, yielding values between 510 and 700 ppm for batch melting and 400–550 ppm for fractional melting models. These findings point to a hydrous asthenospheric source, likely linked to Mesozoic‐Paleogene subduction events of the Penninic Ocean, which introduced significant water into sub‐lithospheric depths. Our results suggest that intraplate basaltic melt generation can be influenced by long‐lived water‐rich zones preserved in the upper mantle.

A Systematic Study of the Structural Properties of Technical Lignins.

Technical lignins are globally available and a sustainable feedstock. The unique properties of technical lignins suggest that these materials should have several industrial applications. The main proposal of this study is to evaluate the relationship between the structure and properties of two technical lignins. Morphological, chemical, physical, and thermal properties of sodium lignosulfonate (LGNa) and magnesium lignosulfonate (LGMg) were investigated. The results showed that a higher formation of intramolecular hydrogen bonds may occur in lignins with a higher content of phenolic hydroxyl groups, such as LGMg. As a result, an increase in the energy of hydrogen bonds in the lignosulfonate structure was observed, without significant change in the hydrogen bond distances. In addition, higher content of phenolic hydroxyl groups might also reduce lignosulfonates thermal stability. The combustion index value was three times higher for LGMg than for LGNa. The characterization study also revealed that phenolic hydroxyl groups influence the main properties of technical lignins and can be a determining factor when these lignosulfonates are used in industrial applications.

Simultaneously reinforce and de-color nanocellulose/lignin composite films by tuning hydroxyl groups with sodium borohydride

Researchers utilized NaBH4 to gently modify alkali lignin, resulting in L-Sx-ty-Pz with high hydroxyl value and decolorization, significantly enhancing the strength of composite films with cellulose nanofibers (CNF). Without strict pH control, the hydroxyl content of the modified lignin reached as high as 9.14 mmol/g. The CF/L-S1-t120-Pu composite film achieved a maximum stress of 45.33 MPa, representing a 116% and 77% increase compared to pure CNF and crude alkali lignin composite films, respectively. The reduction effect of NaBH4 imparted transparency to the film, broadening its applications. Additionally, the film's excellent antibacterial and flame-retardant properties provide strong support for industrial utilization.

Phenolic Hydroxyl‐Activated Lignin for Preparation of Extreme Environments Adaptive Adhesives

ABSTRACTEpoxy resins is widely applied in various industrial production. Lignin exhibits enormous potential as an alternate for health‐risk compound, bisphenol A, in the preparation of epoxy resin adhesives. However, the complicated structures and low reactivity limit the further utilization of lignin. In this study, a green deep eutectic solvent (DES) was utilized to enhance the phenolic hydroxyl content of hard wood organic lignin, from 3.63 to 5.63 mmol/g, to promote the reactivity of lignin during the preparation process of epoxy resin adhesives. Enabling by the DES induced lignin activation, the prepared lignin‐based epoxy resin exhibited excellent epoxy‐value (0.41 mol/100 g) and the as‐prepared adhesives possessed remarkable mechanical properties (tensile stress up to 50.86 MPa). Even after exposure to extreme conditions (freezing or soaking for 48 h), the adhesives maintained over 70% mechanical strength. This work contributes to the broader effort towards sustainable lignin‐based adhesives in industrial applications.

Pretreatment of enzymatic hydrolysis lignin based on deep eutectic solvent containing a reversibly-soluble base.

The pretreatment with green deep eutectic solvents (DESs) is conducive to realizing the high-efficiency utilization of lignin at a low cost. In this study, an innovative choline chloride/urea/calcium hydroxide (ChCl/UR/Ca(OH)2) DES containing a reversibly-soluble base Ca(OH)2 was developed for the pretreatment of enzymatic hydrolysis lignin (EHL). The lignin pretreatment effects of the proposed ChCl/UR/Ca(OH)2 DES were compare with a series of DESs. The results indicated that ChCl/UR/20 % Ca(OH)2 with a reversibly-soluble base addition of 20 % was permitted to achieve the optimal recovery yield of 81.067 % under mild conditions (80 °C, 7 h). The physical and chemical structure, molecular weight, thermal stability, content of phenolic hydroxyl and carboxyl groups, and recycling performance of DES were compared between ChCl/UR-L and ChCl/UR/20 % Ca(OH)2-L. The results showed that ChCl/UR/20 % Ca(OH)2-L retained the lignin skeleton structure and possessed preferable thermal stability and antioxidant activity, which was mainly attributed to the homogeneous molecular structure and abundant phenolic hydroxyl group contents. ChCl/UR/20 % Ca(OH)2 was more advantageous for recycling, maintaining a lignin recovery yield of 57.400 % after 5 cycles, which was higher than that of most acidic and neutral DESs for regenerating lignin. This work provides a valuable reference on the valorization of lignin by using renewable DES.

Enhancing the water resistance properties of bamboo particleboard by reconstructing lignocellulose through carbonization treatment

Bamboo particleboards are recognized as a highly promising alternative to traditional wood particleboards owing to their short growth cycle, abundant availability, and exceptional mechanical properties. However, bamboo particleboards frequently exhibit undesirable hygroscopicity, which limits their broader applications. This study introduces a straightforward and inhibitor-free carbonization treatment method to enhance the water resistance properties of bamboo particleboards. During the carbonization process, the degradation of hemicelluloses and amorphous cellulose, combined with the condensation reactions among lignin molecules, leads to a significant reduction in the hydrophilic hydroxyl and carbonyl group content, resulting in a more compact micro-fibril structure. Concurrently, the degradation of specific macromolecules within the cell wall facilitates the crushing of bamboo during particleboard pressing, thereby reducing the macroscopic pore size between the particles in the board. When compared to the original bamboo particleboard, the moisture absorption, 24-h water absorption (at a relative humidity of 50 %), 24-h thickness swelling, and bound water content of the deep carbon bamboo particleboard decreased by 32.28 %, 81.57 %, 67.16 %, and 66.7 %, respectively, while the water contact angle increased by 88.89 %.

Oxidant concentrations and photochemistry in a vehicle cabin.

Indoor air quality (IAQ) in vehicles can be important to people's health, especially for those whose occupations require them to spend extensive time in vehicles. To date, research on vehicle IAQ has primarily focused on direct emissions as opposed to chemistry happening in vehicle cabins. In this work, we conducted time-resolved measurements of the oxidants and oxidant precursors ozone (O3), nitric oxide (NO), nitrogen dioxide (NO2), and nitrous acid (HONO) inside the cabin of a 2012 Toyota Rav4 under varying ventilation conditions (i.e., car off, car on with passive ventilation, car on with mechanical ventilation via the recirculating fan, and car on with mechanical ventilation via the direct fan). Ozone levels inside the vehicle were significantly lower than outdoors under most conditions, and were approximately half the outdoor levels when the direct fan was in operation. Nitric oxide and NO2 concentrations were very low both inside the vehicle and outdoors. Nitrous acid levels in the vehicle were lower than reported values in other indoor environments, though much higher than expected outdoor levels. We also investigated the potential for photochemical production of radicals in the vehicle. Time- and wavelength-resolved solar irradiance spectra were collected, and steady state hydroxyl radical (OH) and nitrate radical (NO3) concentrations were calculated. Steady state OH concentrations were predicted to be similar to those in air masses in residences illuminated by sunlight, suggesting the importance of HONO photolysis in vehicles. Conversely, nitrate radicals (NO3) were not considered significant indoor oxidants in our study due to rapid titration by NO. Overall, our findings emphasize the importance of both air exchange and photochemistry in shaping the composition of air inside vehicles.

Emerging boron nitride nanosheets: A review on synthesis, corrosion resistance coatings, and their impacts on the environment and health

Abstract The aim of this study is to assess the effectiveness of hexagonal boron nitride (hBN) coatings to enhance the corrosion resistance of metals as well as evaluate their crucial toxicological impacts on both the environment and human health. Organic coatings are extensively applied in the field of protecting metals against corrosion. They are preferred as corrosion inhibitors due to their carbonyl and hydroxyl group content, but they have drawbacks regarding brittleness, porosity, and oxidation susceptibility. In this review, we mainly focused on the synthesis, properties, and applications of hBN coatings and emphasized the way to improve corrosion resistance in metals and alloys. Furthermore, our discussion demonstrated that the boron nitride nanosheet (BNNS) coatings significantly improve corrosion resistance, hydrophobicity, and crack mitigation properties. The researchers achieved reduced coating porosity and enhanced protection against corrosive media by effectively dispersing BNNS in organic resin. This study also determines the protective mechanism of BNNS composite coatings against corrosion. Moreover, we addressed the impact of BBNS synthesis and its physicochemical properties on the environment and organisms. Finally, suggestions are made for future research and the sustainability of industrial use to broaden the scope of applications for BNNS composite coating.

Narrative Review of Free Radicals and Reactive Oxygen Species in Otitis Media.

Many studies have evaluated the roles of free radicals and reactive oxygen species (ROS) in various diseases. To date, however, no systematic review has specifically investigated the involvement of free radicals and ROS in acute otitis media (OM), OM with effusion, and chronic OM. The present study therefore assessed the roles of free radicals and ROS in OM. SCOPUS, PubMed, Cochrane Library, EMBASE, and Google Scholar were comprehensively searched to identify studies assessing the roles of free radicals and ROS in OM. Relevant studies were identified and their findings summarized. The literature search identified 21 studies. A review of their findings showed that the concentrations of hydrogen peroxide (H2O2), lipid hydroperoxide (LPO), and myeloperoxidase (MPO) were elevated in patients with acute OM; that the concentrations of H2O2, LPO, MPO, xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GPX), malondialdehyde (MDA), hydroxyl radical (·OH), and nitrotyrosine were elevated in patients with OM with effusion; and that the levels of nitric oxide (NO), MPO, 4-hydroxynonenal (4-HNE), and malondialdehyde (MDA) were elevated in patients with chronic OM. Although some studies reported that SOD levels were increased in patients with OM with effusion, decreases in antioxidants such as SOD and catalase, as well as total antioxidant capacity, were observed across all types of OM. Although the levels of free radicals and ROS varied by type of OM, study design, control group selection, sample type, ROS and free radical markers, and antioxidant types, most studies showed increased ROS and decreased antioxidants in OM patients. These findings suggest that levels of free radicals and ROS are strongly associated with the pathophysiology of OM.

Efficient Separation of Poplar Lignin Using a New Carboxylic Acid-Based Deep Eutectic Solvents - Choline Chloride/Malonic Acid.

Separation of lignin by pretreatment is an important step in biomass refining. This study investigated how a novel dicarboxylic acid-based deep eutectic solvent (DES) - choline chloride (ChCl)/malonic acid (MA) - affected the process of separating lignin from poplar. At 140 °C for 3.0 h, with a ChCl: MA molar ratio of 1: 3.5, the ideal pretreatment conditions were met, and 91.8 % lignin was obtained. Even after five DES reuses, the consistent and effective separation efficiency of 77.9 % remains unchanged. The hydrolysate contained 92.4 % of the recovered lignin, with a purity of 94.6 %. Moreover, the regenerated lignin obtained through the new DES pretreatment exhibited a high phenolic hydroxyl content of 1.9 mmol g-1 and a low polydispersity index of 1.4. The results showed efficient and selective separation of lignin using the new binary carboxylic acid-based DES pretreatment was achieved. This research offers a novel approach to effectively separate wood fiber biomass and extract valuable lignin.