Hydrogen Peroxide Treatment of Softwood-Derived Poly(Ethylene Glycol)-Modified Glycol Lignin at Room Temperature.

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 ß-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., ß-O-4 linkages), which were prepared from different source-wood-meal sizes and PEG molecular masses.

Usefulness of intraoperative monitoring for mesenteric lymph node metastasis in transplanted free jejunum.

We herein report a rare case of a patient with hypopharyngeal squamous cell carcinoma (SCC) who presented with recurrent metastasis in the mesenteric lymph node of a transplanted jejunum. Removal of the metastatic lymph node required resection of the nutrient vessels which risked the current state of the transplanted jejunum. Importantly, although the nutrient vessels were resected, the jejunum did not become necrotic. This case and another similar case indicate that it may be possible to predict the viability of a transplanted jejunum where jejunal nutrient vessels must subsequently be resected. Key indicators for jejunal survival include determining jejunal blood flow by intraoperative indocyanine green fluorescence imaging, confirming good jejunal color and observation of peristaltic movement by intraoperative blood flow blockage of nutrient vessels. In conclusion, if intraoperative indocyanine green fluorescence imaging in the entire jejunum can be confirmed, there is a high possibility that the jejunum can be well preserved. The clinical presentation and clinical course are described with a proposed new schema of the resectable site of the transplanted jejunal mesentery.

Effect of Heat Treatment on the Chemical Structure and Thermal Properties of Softwood-Derived Glycol Lignin.

A large-scale glycol lignin (GL) production process (50 kg wood meal per batch) based on acid-catalyzed polyethylene glycol (PEG) solvolysis of Japanese cedar (JC) was developed at the Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan. JC wood meal with various particle size distributions (JC-S < JC-M < JC-L) (average meal size, JC-S (0.4 mm) < JC-M (0.8 mm) < JC-L (1.6 mm)) and liquid PEG with various molecular masses are used as starting materials to produce PEG-modified lignin derivatives, namely, GLs, with various physicochemical and thermal properties. Because GLs are considered a potential feedstock for industrial applications, the effect of heat treatment on GL properties is an important issue for GL-based material production. In this study, GLs obtained from PEG400 solvolysis of JC-S, JC-M, and JC-L were subjected to heating in a constant-temperature drying oven at temperatures ranging from 100 to 220 °C for 1 h. All heat-treated GL series were thermally stable, as determined from the Klason lignin content, TMA, and TGA analyses. SEC analysis suggests the possibility of condensation among lignin fragments during heat treatment. ATR-FTIR spectroscopy, thioacidolysis, and 2D HSQC NMR demonstrated that a structural rearrangement occurs in the heat-treated GL400 samples, in which the content of α-PEG-ß-O-4 linkages decreases along with the proportional enrichments of ß-5 and ß-ß linkages, particularly at treatment temperatures above 160 °C.

Selective production of bio-based aromatics by aerobic oxidation of native soft wood lignin in tetrabutylammonium hydroxide.

Aerobic oxidation of native soft wood lignin in an aqueous solution of Bu4NOH facilitates efficient production of vanillin (4-hydroxy-3-methoxybenzaldehyde), which is one of the platform chemicals in industry. Oxidation of Japanese cedar (Cryptomeria japonica) wood flour at 120 °C for 4 h under O2 in Bu4NOH-based aqueous solutions produced vanillin in 23.2 wt% yield based on the Klason lignin content of the starting material. This yield was comparable to that in alkaline nitrobenzene oxidation of the same material (27.2%), which indicated that our aerobic oxidation exploited the full potential of the wood flour for vanillin production. Further mechanical investigation with lignin model compounds suggested that the vanillin formation occurred mainly through following successive reactions: alkaline-catalyzed degradation of ß-ether linkages in middle units of lignin polymer to form a glycerol end group, oxidation of the glycerol end group by O2 to a HCα[double bond, length as m-dash]O moiety, and release of vanillin from the HCα[double bond, length as m-dash]O end. One of the reasons for the high performance of Bu4NOH for the vanillin production was explained by the general understanding in organic chemistry that Bu4OH is a stronger base than simple alkali, e.g. NaOH. The other more fundamental mechanical aspect was that Bu4N+ suppressed disproportionation of the vanillin precursor (the CαHO end group) probably due to strong interaction between the cation and the HCα[double bond, length as m-dash]O end group.

Solvent-Free Fabrication of an Elastomeric Epoxy Resin Using Glycol Lignin from Japanese Cedar.

In this study, a simple formulation of softwood-derived glycol lignin (GL)-based epoxy resin with a high GL content of greater than 50 wt % was demonstrated by direct mixing with poly(ethylene glycol) diglycidyl ether (PEGDGE), an aliphatic epoxide, without using any solvent. Because the GL powder produced from poly(ethylene glycol) (PEG400) solvolysis of Japanese cedar softwood meal was a PEG400-modified lignin (GL400), a strong affinity between PEG counterparts facilitates the uniform mixing of GL400 with PEGDGE, and one component uncured GL400/PEGDGE epoxy resin was prepared at a relatively lower temperature (100 °C) than the curing temperature (130 °C). The epoxy curing reaction was monitored by 1H NMR and Fourier transform infrared spectroscopies. The physical and mechanical properties of the epoxy resins with different GL400 contents were then evaluated. The developed resins exhibited good flexibility and elasticity depending on the GL400 content.

Flexible Electronic Substrate Film Fabricated Using Natural Clay and Wood Components with Cross-Linking Polymer.

Requirements for flexible electronic substrate are successfully accomplished by green nanocomposite film fabricated with two natural components: glycol-modified biomass lignin and Li+ montmorillonite clay. In addition to these major components, a cross-linking polymer between the lignin is incorporated into montmorillonite. Multilayer-assembled structure is formed due to stacking nature of high aspect montmorillonite, resulting in thermal durability up to 573 K, low thermal expansion, and oxygen barrier property below measurable limit. Preannealing for montmorillonite and the cross-linking formation enhance moisture barrier property superior to that of industrial engineering plastics, polyimide. As a result, the film has advantages for electronic film substrate. Furthermore, these properties can be achieved at the drying temperature up to 503 K, while the polyimide films are difficult to fabricate by this temperature. In order to examine its applicability for substrate film, flexible electrodes are finely printed on it and touch sensor device can be constructed with rigid elements on the electrode. In consequence, this nanocomposite film is expected to contribute to production of functional materials, progresses in expansion of biomass usage with low energy consumption, and construction of environmental friendly flexible electronic devices.

Multi-walled carbon nanotube induces nitrative DNA damage in human lung epithelial cells via HMGB1-RAGE interaction and Toll-like receptor 9 activation.

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.

Effect of dietary soy protein on tumor necrosis factor productivity in macrophages from nephritic and hepatoma-bearing rats.

The present study investigated the effect of dietary soy protein isolate (SPI) on tumor necrosis factor-alpha (TNF) productivity in peritoneal macrophages from nephritic and hepatoma-bearing rats. Dietary SPI significantly inhibited the elevated production of TNF by lipopolysaccharide-stimulated macrophages in nephritic and hepatoma-bearing rats compared with dietary casein, while it exerted no influence on the TNF productivity in normal rats. Removal of the minor components contained in SPI by ethanol extraction could significantly or partially restore the reduced TNF production caused by SPI in nephritic and hepatoma-bearing rats, respectively. These results suggest that dietary SPI could suppress the enhanced productivity of TNF associated with the progression of nephritis and hepatoma, and some factors existing in the ethanol extract of SPI are suggested to be involved in suppressing TNF productivity by macrophages.

Characterization of liquefied product from cellulose with phenol in the presence of sulfuric acid.

The average molecular weight, the amount of bound phenol of liquefied cellulose and the substitution pattern of bound phenol as well as newly formed residue in the late stage of liquefaction were examined in various liquefaction conditions. The linkage fashion of bound phenol was governed by the liquefaction condition. Phenol extended molecular weight by the reaction with decomposed fragments from cellulose and formed new residue when insufficient amount was charged. On the other hand, phenol played a role of an end-cap reagent when sufficient amount was charged. Bound phenol with o-substitution increased with increasing liquefaction temperature.

Rapid screening of wood chemical component variations using transmittance near-infrared spectroscopy.

A rapid transmittance near-infrared (NIR) spectroscopy method was developed to predict the variation in chemical composition of solid wood. The effect of sample preparation, sample quantity (single versus stacked multiple wood wafers), and NIR acquisition time on the quantification of alpha-cellulose and lignin content was investigated. Strong correlations were obtained between laboratory wet chemistry values and the NIR-predicted values. In addition to the experimental protocol and method development, improvements in calibration error associated with utilizing stacked multiple wood wafers as opposed to single wood wafers are also discussed.