Novozym435-Gold Nanoparticles Biohybrids as an Efficient Catalyst for Synthesis of Ferulic Acid Starch Ester.

Novozym435-gold nanoparticles biohybrids (NAuB) were synthesized and characterized in this work, with subsequent investigations on their catalytic activities and stability in compared with the initial form of Novozym435. This is a new way to modify immobilized enzyme by physical means. The elemental analysis of NAuB showed that Au was also the major element except C and O. The results of TEM and EDX demonstrated that gold nanoparticles (AuNPs) could be formed in the protein molecular network structure or on the surface of protein in the pores of Novozym435. The optimal process parameters for synthesis NAuB: synthesis temperature of 35 °C, HAuCl4 concentration of 0.02 mg/mL, synthesis time of 24 h. Using the transesterification of starch with ferulic acid ethyl ester as the reaction model, preliminary results pointed to excellent stabilities, solvent tolerance and activities as compared with Novozym435. As for a isooctane:dimethyl sulfoxide system, transesterification of starch with ferulic acid ethyl ester was carried out at 6% (w/w) NAuB and 60 °C for 24 h, a maximum DS of 0.2650 was obtained.

Study of clinical practical model of urinary system injury / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical.</p><p><b>METHODS</b>We have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments. The firearm fragment injuries were made to the bulbous urethra of 10 New Zealand male rabbits. One week preoperatively and 2, 4 and 8 weeks postoperatively, all the animals underwent urethroscopy and urethrography. At 2, 4 and 8 weeks postoperatively, two animals were randomly selected and killed, and the urethra was cut off for pathological examination.</p><p><b>RESULTS</b>The shooting distance of the third generation of firearm fragment wound generator is 2 cm. The best explosive charge of the blank cartridge is 1 g of nitrocotton. All rabbits survived the procedures and stayed alive until they were killed. Injuries were limited to bulbous urethra and distal urethra. Round damaged areas, 1-1.5 cm in length, on the ventral wall were observed. Ureteroscopy results showed that canal diameter gradually shrank by over 50% in 9 rabbits. The rate of success was 90%. Urethrography result noted that a 1-1.3 cm stricture was formed at the bulbous urethra. Histology results of injured stricture urethra showed that fibrous connective tissue hyperplasia and hyaline degeneration caused further stricture in the canal.</p><p><b>CONCLUSIONS</b>The third generation of firearm fragment wound generator imitates the bullet firing process and is more accurate and repeatable. The corresponding rabbit model of traumatic complex urethral stricture simulates the real complex clinical conditions. This animal model provides a standardized platform for clinical researches on treating traumatic injuries to the urinary system.</p>