真菌蛋白模拟肉研究现状及未来展望

随着全球人口的快速增长以及人们对优质蛋白需求的增加,传统动、植物蛋白资源“缺口”问题已逐渐显现,开发新型来源的替代蛋白具有重要的战略意义。应用替代蛋白原料生产的模拟肉可以解决传统肉类供应不足、资源消耗和废物排放量大、动物福利等问题。真菌蛋白作为一种新兴的替代蛋白,具有氨基酸组成均衡全面、膳食纤维丰富、饱和脂肪酸含量低等优点,并且真菌菌丝体的纤维状结构可以很好地还原肉类质地,用于开发模拟肉的潜力巨大。本文综述真菌蛋白的种类、生产过程、营养与安全特性及模拟肉加工技术研究进展,分析真菌蛋白模拟肉产品与市场现状,所面临的挑战以及未来发展方向。

植物基蛋白模拟肉研制技术与发展前景展望

基于营养健康需求差异化、个性化及简约化消费模式特点,分析植物基蛋白模拟肉发展趋势。从研究角度以植物蛋白功能特性为切入点,分析蛋白组织纤维化加工技术研发进展及其对模拟肉制品质构、口感的影响,并进一步分析外源风味与模拟肉制品的协同关系,以提升消费者对模拟肉的认知及对其风味口感的接受度。文章着重总结了模拟肉制品的口感形成原理以及风味改善的方法,为模拟肉生产工艺的优化提供依据和支持。

Training gastroenterology fellows to perform gastric polypectomy using a novel ex vivo model

AIM:To evaluate the effect of hands-on training of gastroenterology fellows in gastric polypectomy using an ex vivo simulator.METHODS:Eight gastroenterology fellows at Mackay Memorial Hospital,Taipei were evaluated in gastricpolypectomy techniques using a pig stomach with artificial polyps created by a rubber band ligation device.The performance of four second year(year-2)fellows who had undergone one year of clinical training was compared with that of four f irst year(year-1)fellows both before and after a 4-h workshop using the ex vivo simulator.The workshop allowed for hands-on train-ing in the removal of multiple artif icial polyps and the placement of hemoclips at the excision site.Evaluation included observation of technical skills,procedure time,and the fellows' conf idence scale.RESULTS:One week after the workshop,the year-1 fellows were re-evaluated and had significantly im-proved mean performance scores(from 17.9 ± 1.8 to 22.5 ± 0.7),conf idence scale(from 4.5 ± 1.0 to 7.8 ± 0.5)and procedure time(from 615.0 ± 57.4 s to 357.5 ± 85.0 s)compared with their baseline performance.After 4 h of training using the ex vivo simulator,the skills of the year-1 fellows were statistically similar to those of the year-2 fellows.CONCLUSION:Use of this ex vivo simulator significantly improved the endoscopic gastric polypectomy skills of gastroenterology fellows who had not had previous clinical training in gastric polypectomy.

Study on the description method of upper limb's muscle force levels during simulated in-orbit operations

The dexterous upper limb serves as the most important tool for astronauts to implement in-orbit experiments and operations. This study developed a simulated weightlessness experiment and invented new measuring equipment to quantitatively evaluate the muscle ability of the upper limb. Isometric maximum voluntary contractions （MVCs） and surface electromyography （sEMG） signals of right-handed pushing at the three positions were measured for eleven subjects. In order to enhance the com- prehensiveness and accuracy of muscle force assessment, the study focused on signal processing techniques. We applied a combination method, which consists of time-, frequency-, and bi-frequency- domain analyses. Time- and frequency-domain analyses estimated the root mean square （RMS） and median frequency （MDF） of sEMG signals, respectively. Higher order spectra （HOS） of bi-frequency domain evaluated the maximum bispectrum amplitude （Bmax）, Gaussianity level （Sg） and lineari- ty level （S0 of sEMG signals. Results showed that B S,, and RMS values all increased as force increased. MDF and Sg val- ues both declined as force increased. The research demonstrated that the combination method is superior to the conventional time- and frequency-domain analyses. The method not only described sEMG signal amplitude and power spectrum, but also deeper characterized phase coupling information and non-Gaussianity and non-linearity levels of sEMG, compared to two conventional analyses. The finding from the study can aid ergonomist to estimate astronaut muscle performance, so as to opti- mize in-orbit operation efficacy and minimize musculoskeletal injuries.

A simulation study on the relation between muscle motor unit numbers and the non-Gaussianity/non-linearity levels of surface electromyography

Recent research has demonstrated that surface electromyography （sEMG） signals have non-Gaussianity and non-linearity properties. It is known that more muscle motor units are recruited and firing rates （FRs） increase as exertion increases. A hy- pothesis was proposed that the Gaussianity test （Sg） and linearity test （St） levels of sEMG signals are associated with the num- ber of active motor units （nMUs） and the FR. The hypothesis has only been preliminarily discussed in experimental studies. We used a simulation sEMG model involving spatial （active MUs） and temporal （three FRs） information to test the hypothesis. Higher-order statistics （HOS） from the bi-frequency domain were used to perform Sg and St. Multivariate covariance analysis and a correlation test were employed to determine the nMUs-Sg relationship and the nMUs-St relationship. Results showed that nMUs, the FR, and the interaction of nMUs and the FR all influenced the Sg and St values. The nMUs negatively correlated to both the Sg and St values. That is, at the three FRs, sEMG signals tended to a more Gaussian and linear distribution as exertion and nMUs increased. The study limited experiment factors to the sEMG non-Gaussianity and non-linearity levels. The study quantitatively described nMUs and the FR of muscle that are not directly available from experiments. Our finding has guiding significance for muscle capability assessment and prosthetic control.

Traveling wave solutions for a diffusive three-species intraguild predation model

The aim of this work is to investigate the existence and non-existence of traveling wave solutions for a diffusive three-species intraguild predation model which means that one predator can eat its potential resource competitors. The method of upper-lower solution is implemented to show the existence of traveling wave solutions. In order to simplify the construction of an admissible pair of upper lower solution, the scheme of strictly con- tracting rectangle is applied. Finally, the minimal speed c＊ of traveling wave solutions of the model is characterized. If the wave speed is greater than c＊, we show the exis- tence of traveling wave solutions connecting trivial and positive equilibria by combining the upper and lower solutions with the contracting rectangle. On the other hand, if the wave speed is less than c＊, the non-existence of such solutions is also established. Furthermore, to illustrate our theoretical results, some numerical simulations are performed and biological meanings are interpreted.

Numerical simulations of reaction-diffusion equations modeling prey-predator interaction with delay

To model biological systems one often uses ordinary and partial differential equations. These equations can be quite good at approximating observed behavior, but they suffer from the downfall of containing many parameters, often signifying quantities which cannot be determined experimentally. For the better understanding of complicated phe- nomena, the delay differential equation approach to model such phenomena is becoming more and more essential to capture the rich variety of dynamics observed in natural systems. In this study, we investigated numerically the influence of delay on the dynam- ics of nonlinear reaction-diffusion equations modeling prey-predator interaction using finite difference scheme subject to appropriate initial and boundary conditions. We first consider the prey-predator with Holling type II functional response where the growth of prey is assumed to be logistic in the sense of predator in one-dimensional space. The effect of delay was investigated with the help of simulations and is compared with the model equation without delay. The proposed method is then extended to two-dimensional space.