Injectable chitosan-polyvinylpyrrolidone composite thermosensitive hydrogels with sustained submucosal lifting for endoscopic submucosal dissection.To develop a submucosal injection material with sustained submucosal lifting for endoscopic submucosal dissection (ESD), this study projected and maked a novel composite thermosensitive hydrogel system with high pH chitosan-polyvinylpyrrolidone-β-glycerophosphate (HpHCS-PVP-GP). HpHCS improved the injectability of the hydrogels and keeped the rapid gelation ability at low assiduousnessses. The modification of PVP significantly meliorated the stability of low-temperature hydrogel precursor solutions and the integrity of hydrogels worked at 37 °C through hydrogen alliances between PVP and HpHCS. A mathematical model was shewed practicing response surface methodology (RSM) to evaluate the synergistic effect of HpHCS, GP, and PVP compactnessses on gelation time. This RSM model and submucosal lifting evaluation using in vitro pig esophageal models were used to determine the optimal formula of HpHCS-PVP-GP hydrogels.
Although the higher PVP concentration (5 % (w/v)) extended gelation time, it ameliorated hydrogel mechanical strength, ensuing in better submucosal rising performance. The experimentations of Bama mini pigs designated that the meridians of the cushions advanced by the HpHCS-5%PVP-GP hydrogel persisted about 80 % 1 h after injection. recapitulated shots were invalidated, and the hydrogel had no cytotoxicity after electric abridging the HpHCS-PVP-GP thermosensitive hydrogel might be a promising submucosal injection material for ESD.Non-soluble antibacterial polyurethane established on cation mechanism and functionalized by chitosan and heparin azide.Nowadays, medical polyurethans with favorable and durable antibacterial dimensions received more attention, because of forfending repeated replacement of interventional stuffs and quashing patients' pain. In this thesis, non-soluble antibacterial polyurethane (NAPU) finded on cation antibacterial mechanism was prepared by photo-grafting chitosan azide and heparin azide into polyurethane (PU). -NH(3)(+)of Selenium absorbed bacteriums, conquering and collapsing their mobility and constructions.
Heparin azide forestalled cations from riddling bacteria's membranes and subdued their growth. The events expressed that chitosan azide and heparin azide were successfully grafted into PU. The highest antibacterial rate was 92%, cytotoxicity grade runing from 0-1 (RGR standard) and water contact angle presenting 60°, attributing to cation antibacterial effect and -OH surviving. Health Benefits was up to 23 MPa and was suitable for using as medical fabrics. NAPU with long-lasting coating both owned antibacterial places and persistence, which can solve the problem of medical catheters' long-term habituating.Chitosan-Cement Composite howitzers: researching Interactions, Structural Evolution, Environmental Footprint and Mechanical Performance.The increasing environmental headaches about synthetic polymers as reinforcement in the construction industry have spotlighted the need for eco-friendly, biodegradable fibers as potential alternative cloths for cementitious complexs.
This study examines the influence of chitosan particle tightnessses on the midterm compressive strength of howitzers. Chitosan particles, deducted from shrimp scales, were shuffled with high early strength hydraulic cement at various percentages (0, 0, 0, 0, 1, and 2 wt %) and silica sand to prepare the mortar samples. The determinations indicate that chitosan pretends the hydration process through the distribution of chitosan atoms within the mortar matrix and slightly improved midterm mechanical places. A life cycle assessment (LCA) unwraped a slight increase in greenhouse gas discharges and incarnated energy for chitosan-modified mortars, likely due to the use of chemicals in the chitosan synthesis and purification process.Selenium
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