羊肉蛋白酶解工艺优化及酶解液中氨基酸含量分析

采用新疆阿勒泰羊后腿肉为原料,以蛋白酶添加比例、酶解时间、pH 值及酶解温度为自变量,以蛋白水解度为评价指标,采用单因素和响应面试验探究木瓜蛋白酶与风味蛋白酶组成的复合酶最佳酶解条件,并测定酶解液中氨基酸含量。结果表明：最佳酶解条件为木瓜蛋白酶与风味蛋白酶体积比1∶2、酶解时间5 h、pH5.5、酶解温度45.7 ℃,此条件下蛋白水解度达到44.22%,与理论值误差较小。最优条件下制备的酶解液中测定出16 种氨基酸,谷氨酸（63.84 g/kg）、甘氨酸（48.37 g/kg）、组氨酸（41.02 g/kg）含量较高,甲硫氨酸（0.07 g/kg）含量最低。     

Dynamic bond exchangeable thermoset vitrimers in 3D-printing

Dynamic bond exchanging vitrimers have emerged recently due to their malleability, self-heal ability, recyclability, and mechanical stability. Likewise, 3D printing is consciously introduced at different platforms for ease of fabrication, high throughput, cost-effectiveness, and waste reduction. These two distinctive techniques have recently made their consensus performance, resulting from a phenomenal change in the printing field. Conventionally, thermoplastic inks have been primarily used in 3D printing, owing to their effortless processability. At the same time, thermosets were utilized for their superior mechanical strength. However, these two essential properties have been required to be presented in the printed material. In that scenario, thermoset vitrimer materials have been introduced in 3D printing, where malleability and mechanical stability have been observed in the same material. Thus, this article details the recent vitrimer material included with the different 3D printing system systems with their reported results to understand and make them widespread. Eventually, the outlook and perspectives could be helpful to understand and enhance this specific field.     

Wireless charging for cardiac pacemakers based on class-D power amplifier and a series–parallel spider-web coil

Biomedical implants (BMIs) and biomedical sensors (BMSs) help to improve quality of life, detect diseases, provide monitoring of vital signs, and take over the role of malfunctioning organs. These implants and sensors require continuous battery power to work effectively, but the batteries used are restricted by their limited capacity and lifetime. This research reported here involved the design and implementation of a wireless charging system based on a series–parallel spider-web coil (WPT-SP-SWC), specifically for cardiac pacemakers. The experimental design investigated several important parameters, including air gap, applied source voltage, coil size, and operating frequency. Performance metrics were evaluated in terms of output DC voltage, delivered output power, and power transfer efficiency. The target voltage was 5 V, which is adequate to charge a BMI such as a pacemaker, and three source voltages (5, 15, and 25 V) were tested. The design was examined at six operating frequencies, ranging from 1.78 MHz to 6.78 MHz. The most favorable results were achieved at 1.78 MHz. Power transfer efficiencies at a 10 mm air gap were 95.75% and 92.08% for applied voltages of 5 V and 15 V, respectively. The effectiveness of the proposed system was also validated by comparing the findings with previous articles.