Preparation and properties of microfibrillated cellulose with different carboxyethyl content.

Carboxyethyl reaction was used as a pretreatment method before grinding and homogenization to prepare microfibrillated cellulose (MFC). The effect of carboxyethylation on the properties of cellulose materials and prepared MFC samples were investigated. Results showed that cellulose materials with different carboxyethyl content were obtained by controlling the chemical dosage. This reaction increased the water retention value, decreased the degree of polymerization and crystallinity, and changed the crystalline structure of cellulose. After pretreatment, the cellulose fibers were easier to be swelled and fibrillated, which greatly reduces the frequency of grinding. In addition, the diameter of the produced MFC decreased with the increase of carboxyl content. The charge density, suspension stability and transparency of MFC increased obviously due to the presence of carboxyethyl groups. This study provides a comprehensive understanding of carboxyethyl pretreatment for the preparation of MFC, which may help to enrich and promote the preparation and application of MFC.

Integrated hot-compressed water and laccase-mediator treatments of Eucalyptus grandis fibers: structural changes of fiber and lignin.

Eucalyptus grandis fibers were treated with hot-compressed water (HCW) and laccase mediator to enhance the fiber characteristics and to produce an active lignin substrate for binderless fiberboard production. The composition, morphology, and crystallinity index (CrI) analysis of fibers showed that the HCW treatment increased the CrI and lignin content of the treated fibers through partial removal of hemicelluloses. Simultaneously, the HCW treatment produced some granules and holes on the surface of the fibers, which possibly facilitated the accessibility of the laccase mediator. Milled wood lignins and enzymatic hydrolysis lignins isolated from the control and treated fibers were comparatively characterized. A reduction of molecular weight was observed, which indicated that a preferential degradation of lignin occurred after exposure to the laccase mediator. Quantitative (13)C, 2D-HSQC and (31)P NMR characterization revealed that the integrated treatment resulted in the cleavage of ß-O-4' linkages, removal of G' (oxidized α-ketone) substructures, and an increase in the S/G ratio and free phenolic hydroxyls.

Preparation and Characterization of Lignocellulosic Oil Sorbent by Hydrothermal Treatment of Populus Fiber.

This study is aimed at achieving the optimum conditions of hydrothermal treatment and acetylation of Populus fiber to improve its oil sorption capacity (OSC) in an oil-water mixture. The characteristics of the hydrolyzed and acetylated fibers were comparatively investigated by FT-IR, CP-MAS 13C-NMR, SEM and TGA. The optimum conditions of the hydrothermal treatment and acetylation were obtained at170 °C for 1 h and 120 °C for 2 h, respectively. The maximum OSC of the hydrolyzed fiber (16.78 g/g) was slightly lower than that of the acetylated fiber (21.57 g/g), but they were both higher than the maximum OSC of the unmodified fiber (3.94 g/g). In addition, acetylation after hydrothermal treatment for the Populus fiber was unnecessary as the increment of the maximum OSC was only 3.53 g/g. The hydrolyzed and the acetylated Populus fibers both displayed a lumen orifice enabling a high oil entrapment. The thermal stability of the modified fibers was shown to be increased in comparison with that of the raw fiber. The hydrothermal treatment offers a new approach to prepare lignocellulosic oil sorbent.

[Improvement effect of vitamins B1, B2 and PP supplementation on substance metabolism of mice exposed to acute hypoxia].

OBJECTIVE: To explore the improvement effect of vitamins B1, B2, PP supplementation to the metabolism changes of carbohydrates, lipids, protein and energy in mice exposed to acute hypoxia. METHODS: Fifty male Kunming mice were randomly divided into normal, acute hypoxia, acute hypoxia plus 2 times, 4 times and 8 times vitamins B1, B2, PP supplemented groups. All mice were fed corresponding diets for two weeks and then except the normal group were exposed to a simulated altitude of 6 000 meters for 8 hours. The changes of glucose, pyruvate, lactate, urea nitrogen, free fatty acids and beta-hydroxybutyric acid from serum, liver glycogen and blood adenosine triphosphate (ATP) concentration were measured. RESULTS: After being exposed to acute hypoxia, the mice glucose, liver glycogen, pyruvate, lactate, free fatty acids, beta-hydroxybutyric acid and urea nitrogen level were increased significantly (P < 0.05), while blood ATP concentration was decreased. In the vitamins B1, B2 and PP supplemented groups, these changes were improved. CONCLUSION: The significant changes in carbohydrate, lipid and protein metabolism were observed in mice exposed to acute hypoxia, and the supplementation of vitamins B1, B2 and PP was proved to be beneficial in improving some metabolic pathways. It is suggested that the supplemented dose of four times was good.

[The metabolic changes of mice serum after loaded swimming].

OBJECTIVE: To investigate the metabolic changes of mice serum after loaded swimming and to provide a basis for the study of anti-fatigue functional food. METHODS: The male Kunming mice were randomly divided into four group, fed an AIN-93 diet for 14 days, and forced to swim for 30, 60 or 120 min, respectively, with a load on their tails. The mice were executed after swimming immediately and the changes of serum metabolic profiles were analyzed using metabolomic approach. The spectrum was acquired by using Carr Purcell Meiboom Gill (CPMG) or Longitudinal Eddy Current Delay (LED) sequence, and transformed into 1H NMR spectrogram via Fourier transformation. All the data were analyzed by principal component analysis by using the SIMCA-P+ software. RESULTS: The serum metabolic profiles changed significantly after loaded swimming. Serum beta-hydroxybutyric acid, acetate, lactate, lipid were increased and glucose, choline, phosphorylcholine, alanine and phosphatidylcholine decreased. These changes were time dependent. CONCLUSION: The changes of serum metabolic profiles after loaded swimming were time dependent, especially for lipid metabolite.Further study based on the interaction of choline and lipid metabolism may contribute to understand the mechanism of fatigue.

Metabolomic study on vitamins B1, B2, and PP supplementation to improve serum metabolic profiles in mice under acute hypoxia based on ¹H NMR analysis.

OBJECTIVE: To explore metabolic changes after acute hypoxia and modulating effect of vitamins B1, B2, and PP supplementation in mice exposed to acute hypoxia. METHODS: Fifty male Kunming mice were randomly divided into 5 groups: normal, acute hypoxia, acute hypoxia with 2, 4 and 8 time-vitamins B1, B2, and PP supplementation. All mice were fed with corresponding diets for two weeks and then were exposed to a simulated altitude of 6,000 meters for 8 h, except for the normal group. Nuclear magnetic resonance analysis was used to identify the changes of serum metabolic profiles. RESULTS: There were significant changes in some serum metabolites under induced acute hypoxia, essentially relative increase in the concentrations of lactate, sugar and lipids and decrease in ethanol. The serum levels of choline, succinate, taurine, alanine, and glutamine also increased and phosphocholine decreased in the acute hypoxia group. After vitamins B1, B2, and PP supplementation, all these metabolic changes gradually recovered. CONCLUSIONS: Significant changes in serum metabolic profile were observed by metabolomics in mice exposed to acute hypoxia, and vitamins B1, B2, and PP supplementation proved to be beneficial to improving some metabolic pathways. It is suggested that the dietary intakes of vitamins B1, B2, and PP should be increased under hypoxia condition.

[Effects of soybean isoflavones on the cell cycles, the cell apoptosis and the proliferation of spleen in radiated mice].

AIM: To study effect of soybean isoflavones (SI) on spleen in radiated mice. METHODS: 90 male mice were randomly divided into control group, radiated group, radiated plus 0.5% dose SI group. After 2-week feeding, the mice received 4.0 Gy 137Cs gamma-radiation, the cell cycles, cell apoptosis and proliferation on the spleen and the spleen index were observed in radiated after 12 h, 24 h, 1 week and 2 weeks. RESULTS: After the mice were radiated, the spleen were significantly atrophy, the rate of the cell apoptosis and the cell cycles of G0-G1 phase in splenocytes were significantly increased (P < 0.01), the cell cycles rate of S phase and the proliferation index were significantly decreased in spleen (P < 0.05). Compared with radiated group, the spleen atrophy and the rate of the cell cycles of G0-G1 phase were significantly decreased (P < 0.05), and the cell cycles of G2-M phase and the proliferation index were significantly increased (P < 0.05) in the mice supplied 0.5% soybean isoflavones. CONCLUSION: The soybean isoflavones could significantly increase spleen radioprotective effect in mice.