Polysaccharides are ideal natural resources for supplements and pharmaceuticals that have received more and more attention over the years. Natural polysaccharides have been shown to have fewer side effects, but because of their inherently physicochemical properties, their bioactivities were difficult to compare with those of synthetic drugs. Thus, researchers have modified the structures and properties of natural polysaccharides based on structure-activity relationships and have obtained better functionally improved polysaccharides. This review focuses on the major modification methods of polysaccharides, and discusses the effect of molecular modification on their physicochemical properties and bioactivities. Molecular modification methods mainly include chemical, physical, and biological changes. Chemical modification is the most widely used method; it can significantly increase the water solubility and bioactivities of polysaccharides by grafting onto other groups. Physical and biological modifications only change the molecular weight of a polysaccharide, and thereby change its physicochemical properties and bioactivities. Most of the molecular modifications bring about an increase in the antioxidant activity of polysaccharides, and among these, sulfated and acetylated modifications are very common. Furthermore, phosphorylation modification is the most common application to increase antitumor activity, and modified polysaccharides have been shown to have anti-HIV activity as the result of sulfated modification.

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Four horizontal subsurface flow constructed wetlands (HSFCWs), named HSFCW1 (three-stage, without step-feeding), HSFCW2 (three-stage, with step-feeding), HSFCW3 (five-stage, without step-feeding) and HSFCW4 (five-stage, with step-feeding) were designed to investigate the effects of dissolved oxygen (DO) and step-feeding on nitrogen removal. High removal of 90.9% COD, 99.1% ammonium nitrogen and 88.1% total nitrogen (TN) were obtained simultaneously in HSFCW4 compared with HSFCW1-3. The excellent TN removal of HSFCW4 was due to artificial aeration provided sufficient DO for nitrification and the favorable anoxic environment created for denitrification. Step-feeding was a crucial factor because it provided sufficient carbon source (high COD: nitrate ratio of 14.3) for the denitrification process. Microbial activities and microbial abundance in HSFCW4 was found to be influenced by DO distribution and step-feeding, and thus improve TN removal. These results suggest that artificial aeration combined with step-feeding could achieve high nitrogen removal in HSFCWs.

The development of biochar has triggered a hot-spot in various research fields including agriculture, energy, environment, and materials. Biochar-based materials provide a novel approach against environmental challenging issues. Considering the rapid development of biochar materials, this review serves as a valuable platform to summarize the recent progress on the theoretical investigation and engineering applications of biochar materials in environmental remediation. For a better understanding of the structure-application relationships, the structural properties of biochar from macroscopic and microscopic aspects are summarized. The multilevel structures including elements, phases, surface chemistry, and molecular are highlighted to elucidate the multi-functional properties of biochars. Sorption, catalysis, redox reaction, and biological activity of biochar are briefly illustrated, which influence the transport, transformation, and removal of organic and inorganic pollutants in the environments. According to the multi-level structures and structure-application relationships of biochar, specific biocharbased materials and devices have been designed for practical environmental application. The important progress on the functionalization and device of biochar-based materials, including magnetic biochars, 2D and 3D biochar-based macrostructures, immobilized microorganism on biochar, and biochar-amended biofilters are highlighted. The environmental friendliness and sustainability of biochar-based materials, considering the whole cycle from synthesis to application, are evaluated.

Double hepatic cancer of HCC and ICC is very rare with distinctive clinicopathologic features. The prognosis of double hepatic cancer was as poor as pure ICC. The ICC component played a more important role than the HCC component in influencing the prognosis of double hepatic cancer.

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