Benefit Effect of Dendrobium officinale Ultrafine Powder on DSS-Induced Ulcerative Colitis Rats by Improving Colon Mucosal Barrier

Aim and Objective. To study the effect of Dendrobium officinale ultrafine powder (DOFP) on the intestinal mucosal barrier in rats with ulcerative colitis (UC) induced by dextran sulfate sodium (DSS). Materials and Methods. After intragastric administration of DOFP for 3 weeks, the rat UC model was made by the administration of 4% oral DSS solution for one week, and the drug was given at the same time. During the experiment, the disease activity index (DAI) score of the rats was regularly computed. At the end of the experiment, the blood routine indexes of rats were obtained. The histopathological changes in the colon were monitored by hematoxylin-eosin (H&E) and PAS staining and observation of ultrastructural changes in the colon by transmission electron microscope. Occludin expression in the colon was monitored by Western blot, the expression of claudin-1 and ZO-1 in the colon was detected by immunofluorescence, and the expression of TNF-α, IL-6, and IL-1β in the colon was detected by immunohistochemistry. Results. The results firstly indicated that DOFP could significantly alleviate the signs and symptoms of the DSS-induced rats UC model, which manifested as improvement of body weight loss, increase of colon length, and improvement of the symptoms of diarrhea and hematochezia. Then, results from histopathology, blood routine examination, and transmission electron microscope analysis further implied that DOFP could dramatically reduce inflammatory cell infiltration and restore intestinal epithelial barrier integrity. In addition, the experiments of Western Blot analysis, immunofluorescence, and PAS staining also further confirmed that DOFP could markedly increase related protein expressions of the intestinal barrier and mucus barrier, as the expression of occludin, claudin-1, and ZO-1 in the colon significantly decreased. The experiments of immunohistochemistry confirmed that DOFP could markedly decrease protein expression levels of inflammatory cytokines TNF-α, IL-6, and IL-1β. Conclusion. DOFP notably alleviated inflammatory lesions, repaired the colon mucosa damage by promoting the expression of tight junction proteins occludin, claudin-1, and ZO-1 and inhibiting the release of inflammatory factors TNF-α, IL-6, and IL-1β, and finally achieved the purpose of treating UC.

Properties of biomass powders resulting from the fine comminution of lignocellulosic feedstocks by three types of ball-mill set-up

Background: Lignocellulosic biomass has many functionalities that hold huge potential for material, energy or chemistry applications. To support advanced applications, the biomass must be milled into ultrafine powder to increase reactivity. This milling unit operation needs to be fully mastered to deliver high-quality standard end-products. Here we studied the relationship between the characteristics of the starting lignocellulosic plant material and the properties of the resulting ultrafine powder in different ball-mill process routes. Methods: Two lignocellulosic biomasses (pine bark and wheat straw) with contrasted compositional and mechanical properties were milled using three ball-mill set-ups delivering different balances of impact force and attrition force. The resulting powders were analysed for particle characteristics (size, agglomeration extent, shape) and powder flow properties (compressibility, cohesion) using a dynamic powder rheometer. Results: Pine bark is more amenable to a fast particle size reduction than the fibrous wheat straw. The resulting pine bark powders appear less compressible but much more cohesive than the straw powders due to particle shape, density and composition factors. The mill set-up working by attrition as dominant mechanical force (vibratory ball mill) produced a mix of large, elongated particles and higher amounts of fines as it acts mainly by erosion, the resulting powder being more prone to agglomerate due to the abundance of fines. The mill set-up working by impact as dominant mechanical force (rotary ball mill) produced more evenly distributed particle sizes and shapes. The resulting powder is less prone to agglomerate due to a preferential fragmentation mechanism. Conclusions: The attrition-dominant mill yields powders with dispersed particle sizes and shapes and the poorest flow properties, while the impact-dominant mill yields more agglomeration-prone powders. The mill set-up working with impact and attrition as concomitant mechanical forces (stirred ball mill) produces powders with better reactivity and flow properties compared to rotary and vibratory mills.

Tribotechnical properties of sintered friction material based on copper with the additives of the ultrafine powder of aluminide of Ti–46Al–8Cr system

The article presents the results of study of the effect of additives of an ultrafine powder of the Ti–46Al–8Cr system obtained by MASHS on the tribotechnical properties of a friction material based on BrO6 bronze. It is shown that in the range of powder additive concentrations 0.5–1.5 wt. %, the dynamic coefficient of friction increases from 0.04 to 0.055, in the range of 1.5–2.5 % – to 0.055–0.058. The introduction of the 0.5–1.0 % Ti–46Al–8Cr powder permitted to reduce the wear rate of the friction material from 4.0 to 3.7 μm/km. An increase in the additive to 2.5 % led to an increase in the material wear rate up to 6 μm/km.