Dendrite Spacing Selection during Directional Solidification of Pivalic Acid-Ethanol System

Unidirectional solidification of pivalic acid （PVA）-ethanol （Eth） mixture was performed to examine whether an allowable range of primary dendrite spacing definitely exists at a given growth velocity and how the range is history-dependent. PVA-0.59 wt pct Eth was unidirectionally solidified in the range of growth velocity 0.5-64 μm/s at the temperature gradient of 2.3 K/ram. Sequential change in growth velocity was imposed to determine the upper and lower limits for the allowable range of stable spacing. An allowable range of the steady state primary spacing was observed at a given growth velocity, and the extent of the range seems to be dependent on the degree to which step-increase or step-decrease in growth velocity is accomplished. As the degree of sequential change in growth velocity increases, the history-dependence of the selection for the primary dendrite spacing tends to disappear.

Synergistic protection of astragalus polysaccharides and matrine against ulcerative colitis and associated lung injury in rats

BACKGROUND Ulcerative colitis(UC)is a main form of inflammatory bowel disease.Due to complicated etiology and a high rate of recurrence,it is quite essential to elucidate the underlying mechanism of and search for effective therapeutic methods for UC.AIM To investigate the effects of astragalus polysaccharides(APS)combined with matrine on UC and associated lung injury.METHODS UC was induced in rats by colon mucosal tissue sensitization combined with trinitro-benzene-sulfonic acid-ethanol.Then,the effects of the treatments of salazopyrine,APS,matrine,and APS combined with matrine on histopathological changes of lung and colon tissues,disease activity index(DAI),colon mucosal damage index(CMDI),serum endotoxin(ET)level,serum diamine oxidase(DAO)activity,the contents of tumor necrosis factor-αand interleukin-1β,and the activities of myeloperoxidase,superoxide dismutase,and malondialdehyde in lung tissues,as well as the protein expression of zonula occludens(ZO)-1,Occludin,and trefoil factor 3(TFF3)were detected in UC rats.RESULTS The treatments of salazopyrine,APS,matrine,and APS combined with matrine reduced DAI scores and improved histopathological changes of colon and lung tissues,as well as decreased CMDI scores,ET levels,and DAO activities in UC rats.Moreover,in lung tissues,inflammatory response and oxidative stress injury were relieved after the treatments of salazopyrine,APS,matrine,and APS combined with matrine in UC rats.Furthermore,the expression of ZO-1,Occludin,and TFF3 in lung and colon tissues was increased after different treatments in UC rats.Notably,APS combined with matrine exerted a better protective effect against UC and lung injury compared with other treatments.CONCLUSION APS combined with matrine exert a synergistic protective effect against UC and lung injury,which might be associated with regulating TFF3 expression.

Characterization and Comparison of Cellulose Extraction from Ginger Stalk by Two Different Chemical Treatments

Agricultural residues are important renewable biomass resources that have not received much research attention. Ginger stalk is a major agricultural waste in China.The extraction of cellulose from ginger stalk would convert this waste into a high value-added product and, simultaneously, contribute to environmental protection. This research studied the characteristics of cellulose extracted from ginger stalk by two different treatments:(i) potassium hydroxide(KOH) treatment and(ii) nitric acid-ethanol(NAE) treatment. The optimal condition for the KOH treatment was obtained, it was at 1∶30 solidto-liquid ratio(SLR) for 5 h extraction time with 14 wt% KOH. The optimal condition for the NAE treatment was as follows: 1∶40 SLR, 4 h extraction time, and a reaction temperature of 90℃. However, the cellulose obtained by NAE treatment was severely degraded than that by KOH treatment. The Fourier-transform infrared(FT-IR) spectroscopy analyses revealed that both treatments successfully dissolved the lignin and hemicellulose. Two treatments showed a higher cellulose yield, and the extracted cellulose had more crystal structure.