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The efficient use of renewable lignocellulosic biomass has attracted wide interest, as it promises to reduce the environmental impact of fossil fuel consumption. A recently developed batch-scale process, which produces glycol lignin (GL) from softwood biomass, generates a considerable amount of cellulose-rich solid residues (SRs) as a byproduct. In this study, usable cellulose was isolated from SRs in the form of carboxylated cellulose nanocrystals (O-CNCs). The properties of O-CNCs were investigated to establish a possible integrated biomass utilization system based on the GL production technology. Three different forms of purified SRs—never-dried (N-Cel), freeze-dried (F-Cel), and vacuum-dried (V-Cel) cellulose—were subjected to oxalic acid (OA) hydrolysis at 95 °C for 4 h. The average length of O-CNCs ranged from 90 to 120 nm and the height ranged from 3 to 6 nm for separate particles and from 8 to 20 nm for aggregates. The carboxyl group content was 0.11–0.23 mmol/g O-CNCs. The overall results indicated that the yields, dimensions, surface charges, and thermal stability of the O-CNCs were largely influenced by the nature of the starting cellulose. In addition, O-CNCs prepared from recycled OA exhibited similar properties to those prepared from fresh OA.

This study investigated the greenhouse gas (GHG) emissions of polyethylene glycol-modified lignin (PEG-modified lignin) from the raw material procurement stage to the production stage based on the production process of PEG-modified lignin in a commercial-scale plant and analyzed the GHG emission reduction by replacing resins derived from fossil resources. The GHG emissions of the PEG-modified lignin were 0.85 kg-CO 2 e/kg. The establishment of a process to recover and recycle used PEG in the product manufacturing process and reduce the input of virgin PEG has a significant impact on reducing GHG emissions. Furthermore, in the production of a masterbatch of PEG-modified lignin mixed with nylon (PA6), GHG emissions were reduced with an increase in PEG-modified lignin content, with reductions of approximately 14 and 36% for the PEG-modified lignin content of 20 and 50%, respectively. This indicates that PEG-modified lignin has the potential to contribute to GHG reduction as an alternative to fossil fuel resources.

Recently, a large-scale production system of softwood-derived poly(ethylene glycol) (PEG)-modified glycol lignin (GL) was developed to produce high-quality lignin derivatives with substantially controlled chemical structures and attractive thermal properties. In this study, the further upgrading of GL properties with carboxy functionalization was demonstrated through the room-temperature hydrogen peroxide (H2O2) treatment with the mass ratio of H2O2 to GL, 1:1 and 1:3, for 7 d. The changes in the chemical structure, carboxy group content, molecular weight, and thermal properties of the insoluble portions of partially oxidized glycol lignins (OGLs) were then investigated. Nuclear magnetic resonance and thioacidolysis data revealed that the oxidative functionalization involved the cleavage of β–O–4 linkages and the oxidative cleavage of guaiacyl aromatic rings into muconic acid-type structures. This was validated by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and potentiometric titration. Overall, the results suggested that the varying outcomes of carboxy group content (0.81–2.04 mmol/g OGL) after 7-d treatment depended on the type of the GL origin having varying amounts of the retained native lignin structure (e.g., β–O–4 linkages), which were prepared from different source-wood-meal sizes and PEG molecular masses.

Glycol lignin (GL) produced via acidic solvolysis of cedar wood meal with polyethylene glycol (PEG) is a highly functional material. In this study, the effects of wood meal particle size and amount of PEG added on the properties of PEG400-modified GLs (GL400s) were examined. For this purpose, cedar wood meal with four different particle sizes ranging between 0.18 and 2.00 mm and PEG400 at liquid ratios of 5 and 3 with respect to the wood meal were used. Acidic solvolysis at 140 °C successfully decreased the amount of solid residue with increasing GL400 yield and reaction time at both liquid ratios of 5 and 3. Overall, wood meal size remarkably affected the physical properties of GL400s at low PEG400 content (liquid ratio 3). In addition, the glass transition temperature Tg and thermal flow temperature Tf increased with decreasing wood meal size. Consequently, GL400s with varying thermal properties (Tg = 63 to 97 °C, Tf = 109 to 149 °C) were successfully prepared by adjusting the PEG400 liquid ratios and wood meal size. The data will support the development of a stable manufacturing process for the mass production of GL.

Head and neck cancers (HNCs) are a heterogeneous group of malignancies, including head and neck squamous cell carcinoma (HNSCC), thyroid carcinoma, and salivary gland carcinoma. Despite multidisciplinary treatment approaches, outcomes for advanced HNCs remain poor. Among these, HNSCC has been the most extensively studied in the field of immunotherapy. Immune checkpoint inhibitors (ICIs), particularly anti‐PD‐1 antibodies, have demonstrated survival benefits in R/M HNSCC, but response rates remain modest at 15%–20%, highlighting the need for more effective strategies. Recent advances include the use of neoadjuvant and adjuvant immunotherapy in locally advanced HNSCC, which may improve pathological response rates and long‐term survival. Additionally, novel immunotherapeutic approaches such as tumor antigen‐targeted cancer vaccines and T‐cell receptor‐engineered T‐cell (TCR‐T) therapy are emerging. These strategies aim to enhance tumor‐specific immunity, especially in tumors lacking targetable driver mutations. The tumor microenvironment (TME) in HNSCC plays a pivotal role in modulating immune response and therapeutic efficacy. Immunomodulatory agents such as HDAC inhibitors, TLR agonists, and VEGF inhibitors have shown promise in enhancing ICI responsiveness by altering the immunosuppressive TME. Moreover, the identification of predictive biomarkers, including PD‐L1 expression, tumor mutational burden, and tertiary lymphoid structures, is crucial for patient selection and response prediction. This review provides a comprehensive overview of the current landscape and future directions of immunotherapy for HNCs, with a particular focus on HNSCC. We highlight ongoing clinical challenges and discuss emerging strategies aimed at overcoming resistance and improving clinical outcomes. ICI‐included therapies are standard for R/M HNSCC patients. In particular, neoadjuvant ICI therapy shows promising clinical results even in nontreated resectable HNSCC patients. In addition, cancer vaccine, immune cell‐based therapy, immunomodulation therapy, and TME targeting therapy may combine with ICI.

The valorization of lignin to value-added basic chemicals is one of the most important technologies for efficient carbon recycling. While many catalytic systems have been developed for cleavage of monolignol linkages, especially for β-O-4 structures, the low solubility of lignin, which originates from its complicated polymeric structure, often makes it difficult to apply these catalytic process to degradation of real lignin-derived materials. Here, we investigated the degradation of poly(ethylene glycol)-modified lignin with transition metal complexes. Monolignols (4-methyl, 4-ethyl- and 4-propyl-guaiacol) were obtained as the degradation products. Although low solubility after detachment of the PEG moiety hampered efficient degradation, the addition of PEG for in situ protection of the hydroxy group was effective in maintaining the lignin solubility and improving the monolignol yields.The hydrogenolysis of PEG-modified soluble lignin was investigated with series of transition metal complexes to afford alkyl guaiacols. Although the introduced PEG moiety was also susceptible against the hydrogenolysis, in situ modification in PEG solvent was found effective for maintaining the lignin soluble and improved degradation efficiency.

Glycol lignins (GLs) produced through acid-catalyzed solvolysis of softwood meal using glycols, such as polyethylene glycol (PEG), have been used for the development of functional materials. In this study, GLs with various physical and chemical properties were synthesized via solvolysis with monomethyl ethers of polyethylene glycol (MPEG), such as MPEG-n4 and MPEG-n8. The effects of the reaction time and temperature on the yield, molecular weight, and thermal properties of MPEG-lignin were studied. The yield of MPEG-lignin increased with the solvolysis time. Acid-catalyzed solvolysis using MPEG-n4 occurred faster than that using MPEG-n8. Higher reaction temperature resulted in a higher yield of MPEG-lignin with a higher glass transition temperature (Tg) and viscous thermal flow temperature (Tf). The Tg and Tf of MPEG-lignins increased with the solvolysis time. The MPEG-lignins synthesized at higher reaction temperatures showed a relatively strong carbonyl absorbance band in the infrared spectra, which was ascribed to decomposed sugar derivatives.

Glycol lignins (GLs) produced through acid-catalyzed solvolysis of softwood meal using glycols, such as polyethylene glycol (PEG), have been used for the development of functional materials. In this study, GLs with various physical and chemical properties were synthesized via solvolysis with monomethyl ethers of polyethylene glycol (MPEG), such as MPEG-n4 and MPEG-n8. The effects of the reaction time and temperature on the yield, molecular weight, and thermal properties of MPEG-lignin were studied. The yield of MPEG-lignin increased with the solvolysis time. Acid-catalyzed solvolysis using MPEG-n4 occurred faster than that using MPEG-n8. Higher reaction temperature resulted in a higher yield of MPEG-lignin with a higher glass transition temperature (Tg) and viscous thermal flow temperature (Tf). The Tg and Tf of MPEG-lignins increased with the solvolysis time. The MPEG-lignins synthesized at higher reaction temperatures showed a relatively strong carbonyl absorbance band in the infrared spectra, which was ascribed to decomposed sugar derivatives.

Vanillin is one of the industrially important compounds that can be produced from lignin. This study presents production of vanillin and vanillic acid (oxidized form of vanillin) through aerobic oxidation of Japanese cedar ( Cryptomeria japonica ) at 120 °C for 72 h in aqueous alkali solutions with several Bu 4 N + and OH − concentrations (1.25, 2.50, and 3.75 mol/L), where Bu 4 N + is an enhancer of the vanillin formation reported in our previous study. The concentrations of Bu 4 N + and OH − were adjusted by the additions of Bu 4 NCl and solid NaOH into the base medium Bu 4 NOH·30H 2 O, which forms 1.25 mol/L aqueous solution of Bu 4 NOH at the elevated temperature. Vanillin and vanillic acid were produced with the maximum yields of 21.0 and 1.7 wt% (lignin-base), respectively, at the 1.25 mol/L Bu 4 N + and 3.75 mol/L OH − concentrations. This vanillin yield is close to that obtained by the alkaline nitrobenzene oxidation (26.5 wt%), indicating significantly high selectivity of our lignin degradation with Bu 4 N + toward vanillin formation. We also proposed a novel Bu 4 NOH·30H 2 O-free reaction medium, where Bu 4 NOH·30H 2 O as the base medium were substituted with an aqueous solution of Bu 4 NCl and NaOH to avoid using expensive Bu 4 NOH·30H 2 O. The treatment of the Japanese cedar with this alternative medium exhibited the moderately decreased vanillin yield of 14.6 wt%, which is, however, much higher than the vanillin yield obtained with a simple 1.25 mol/L NaOH solution.

Background Carbon nanotube (CNT) is used for various industrial purposes, but exhibits carcinogenic effects in experimental animals. Chronic inflammation in the respiratory system may participate in CNT-induced carcinogenesis. 8-Nitroguanine (8-nitroG) is a mutagenic DNA lesion formed during inflammation. We have previously reported that multi-walled CNT (MWCNT) induced 8-nitroG formation in lung epithelial cells and this process involved endocytosis. To clarify the mechanism of CNT-induced carcinogenesis, we examined the role of Toll-like receptor (TLR) 9, which resides in endosomes and lysosomes, in 8-nitroG formation in human lung epithelial cell lines. Methods We performed immunocytochemistry to examine 8-nitroG formation in A549 and HBEpC cells treated with MWCNT with a length of 1-2 μm (CNT-S) or 5-15 μm (CNT-L) and a diameter of 20-40 nm. We examined inhibitory effects of endocytosis inhibitors, small interfering RNA (siRNA) for TLR9, and antibodies against high-mobility group box-1 (HMGB1) and receptor for advanced glycation end-products (RAGE) on 8-nitroG formation. The release of HMGB1 and double-stranded DNA (dsDNA) into the culture supernatant from MWCNT-treated cells was examined by ELISA and fluorometric analysis, respectively. The association of these molecules was examined by double immunofluorescent staining and co-immunoprecipitation. Results CNT-L significantly increased 8-nitroG formation at 0.05 μg/ml in A549 cells and its intensity reached a maximum at 1 μg/ml. CNT-L tended to induce stronger cytotoxicity and 8-nitroG formation than CNT-S. Endocytosis inhibitors, TLR9 siRNA and antibodies against HMGB1 and RAGE largely reduced MWCNT-induced 8-nitroG formation. MWCNT increased the release of HMGB1 and dsDNA from A549 cells into culture supernatant. The culture supernatant of MWCNT-exposed cells induced 8-nitroG formation in fresh A549 cells. Double immunofluorescent staining and co-immunoprecipitation showed that TLR9 was associated with HMGB1 and RAGE in lysosomes of MWCNT-treated cells. Conclusions MWCNT induces injury or necrosis of lung epithelial cells, which release HMGB1 and DNA into the extracellular space. The HMGB1-DNA complex binds to RAGE on neighboring cells and then CpG DNA is recognized by TLR9 in lysosomes, leading to generation of nitric oxide and 8-nitroG formation. This is the first study demonstrating that TLR9 and related molecules participate in MWCNT-induced genotoxicity and may contribute to carcinogenesis.