Phenomenological Modeling of Formic Acid Fractionation of Sugarcane Bagasse by Integration of Operation Parameters as an Extended Combined Severity Factor.

In order to more conveniently simulate and optimize the solubilization of sugarcane bagasse components during formic acid (FA) fractionation, an extended combined severity factor (CSFext) was defined to integrate various operation parameters as a single factor. Two phenomenological models based on Arrhenius and Logistic equations were further used to describe the phenomenological kinetics. Different data-processing methods were compared to fit the severity parameters and model constants. Both Arrhenius-based and Logistic-based models show satisfying fitting results, though the values of Arrhenius-based CSFext (A-CSFext) and Logistic-based CSFext (L-CSFext) were somewhat different under the same fractionation condition. The solubilization of biomass components increased with CSFext, but two distinct stages could be observed with inflection points at A-CSFext of 42 or L-CSFext of 43, corresponding to bulk and residual solubilization stages, respectively. For the enzymatic hydrolysis of cellulosic solids, the highest initial enzymatic glucan conversion (EGC@6h) was obtained at A-CSFext of 39-40 or A-CSFext of 40-41; however, for a long hydrolysis period (72 h), relatively high glucan conversion (EGC@72h) was observed at A-CSFext of 42-43 or A-CSFext of 43-44. Post-treatment for deformylation with a small amount of lime could help to recover the cellulose digestibility.

Preparation of formyl cellulose and its enhancement effect on the mechanical and barrier properties of polylactic acid films.

Cellulose was modified by formic acid to prepare formyl cellulose (FC). The amount of formyl groups in FC was adjusted by controlling the reaction time, reaction temperature, and formic acid concentration. Then, FC was used to reinforce polylactic acid (PLA) films prepared by solution casting. Scanning electron microscopy (SEM) shows that long rod-like cellulose particles were broken into short rods after formylation and the introduction of FC made PLA surface rougher. The mechanical properties of PLA/FC films were improved by the inclusion of FC. Compared to pure PLA film, the PLA/FC composite film with 1 wt% FC (containing 15.79% formyl groups) showed a 48.59% increase in tensile strength and a 346% increase in Young's modulus. The addition of FC also resulted in better water barrier properties. The moisture absorption capacity and water vapor permeability were 40.56% and 51.43% lower than those of the pure-PLA film. The enhancement in properties for PLA/FC composites could be ascribed to the improved compatibility between PLA and cellulose with the introduction of hydrophobic formate groups. The PLA/FC composite films developed in this work could be highly potential for food packaging.

[Effects of Oridonin on Proliferation Apoptosis of Human Multiple Myeloma Cells H929 in Vitro].

OBJECTIVE: To investigate the effects of oridonin (ORI) on the proliferation and apoptosis of human multiple myeloma cell line H929 and its possible mechanism. METHODS: H929 cells were exposed to ORI 0、4、8、12、16、20、24、28、32 µmol/L for 12, 24 and 36 hours respectively. The prolifcration inhibitory effect of ORI on H929 cells was determined by MTT assay and then the working concentrations of ORI were determined. The morphological changes and apoptosis of H929 cells were observed by TUNEL (TdT-mediated dUTP Nick-End Labeling) and fluorescence microscopy. The apoptosis rate of H929 cells was detected by flow cytometry with Annexin V-FITC/PI staining. The protein expressions of pro-caspase-3, BCL-2，p-PI3K, p-Akt, BAX, Cleaved PARP and p-JNK, p-ERK and p-p38 in H929 cells were detected by Western blot. RESULTS: Compared with the control group, the proliferation of H929 cells treated with the ORI of 8-16 µmol/L was significantly inhibited and the apoptosis of H929 cells was obviously increased in dose- and time-dependent manners. As for morphological changes, the characteristics of apoptotic cells were presented in H929 cells treated with ORI for 24 hours. The protein levels of pro-caspase-3, BCL-2，p-PI3K, p-Akt were down-regulated with increasing of ORI concentration（r=0.9861, r=0.9725, r=0.9413, r=0.9373）, while the BAX, Cleaved PARP and p-JNK, p-ERK and p-p38 were up-regulated（r=0.9178, r=0.8877, r=0.882, r=0.9645, r=0.8623）. CONCLUSION: The ORI possesses anti-myeloma effects, can inhibit the proliferation and induce the apoptosis of H929 cell line in vitro. Its potential mechanism may be related with up-regulating the MAPK and down-regulating the PI3K/Akt signal pathways.