Flocculation properties of cellulose-acrylamide graft copolymers

The flocculation of aqueous suspension of microcrystalline cellulose powder grafted with polyacrylamide was studied. The correlation between the initial flocculation rate measured by means of turbidimetry and the length and number of the grafted polymer chain was discussed from the viewpoint of polymer bridging mechanism. The effect of the graft copolymer powder on the flocculation of kaolin suspension was also investigated.     

High temperature resistivity of pyrolytic graphite bromine residual compounds

The electrical resistivity of pyrolytic graphite (PG) deposited at 2300°C decreases in both the a- and c-axis directions as the temperature is increased up to 1000°C, but the high temperature resistivity of PG-bromine residual compounds differ somewhat from that of the original PG. When the temperature is increased, the a-axis resistivity remains nearly constant at the lower temperature range but increases rapidly between 300 and 500°C. Above 500°C the value of the resistivity approaches that of the original PG. On cooling, the change of the electrical resistivity of PG-bromine residual compounds is the same as that on heating, but its value is larger between 500 and 100°C. At room temperature, the a-axis resistivity of the compound before and after the cyclic heat-treatment is the same. This behaviour is closely related to the c-axis thermal expansion and is well explained by the same bromine vaporisation model. As to the c-axis direction, the electrical resistivity of PG-bromine residual compounds show a different behaviour. However, the factors affecting the electrical conduction in this case are complicated and cannot be resolved.     

Inhibitory Effects of Saururus chinensis Extract on Receptor for Advanced Glycation End-Products-Dependent Inflammation and Diabetes-Induced Dysregulation of Vasodilation

Advanced glycation end-products (AGEs) and the receptor for AGEs (RAGE) are implicated in inflammatory reactions and vascular complications in diabetes. Signaling pathways downstream of RAGE are involved in NF-κB activation. In this study, we examined whether ethanol extracts of Saururus chinensis (Lour.) Baill. (SE) could affect RAGE signaling and vascular relaxation in streptozotocin (STZ)-induced diabetic rats. Treatment with SE inhibited AGEs-modified bovine serum albumin (AGEs-BSA)-elicited activation of NF-κB and could compete with AGEs-BSA binding to RAGE in a dose-dependent manner. Tumor necrosis factor-α (TNF-α) secretion induced by lipopolysaccharide (LPS)—a RAGE ligand—was also reduced by SE treatment in wild-type Ager^+/+ mice as well as in cultured peritoneal macrophages from Ager^+/+ mice but not in Ager^−/− mice. SE administration significantly ameliorated diabetes-related dysregulation of acetylcholine-mediated vascular relaxation in STZ-induced diabetic rats. These results suggest that SE would inhibit RAGE signaling and would be useful for the improvement of vascular endothelial dysfunction in diabetes.     

Solubility of silica-alumina gels in different pH solutions Discussion on the hydration of slags and fly ashes in cement

The solubility of silica-alumina gels with different compositions were measured in different pH solutions. The solubilities of a silica-alumina gel is remarkably affected by its composition and the pH of the solution. There is a gel with a composition of Si/Al atomic ratio of about 7/3. When the Al/(Si+Al) ratio of silica-alumina gel is less than 0.7, the composition of the liquid phase is more rich in Al₂O₃ than that of the gel, that is, the surface of gel becomes rich in SiO₂. Conversely, when the Al/(Si+Al) ratio of gel is more than 0.7, the composition of the liquid phase is more rich in SiO₂ than that of the gel, and the surface of gel becomes rich in Al₂O₃. In the hydration of silica-alumina glasses such as slag and fly ash, the reason why the hydration proceeds or not, is whether the surface of reacting glass becomes rich in Al₂O₃ or not.