利用激光共聚焦显微镜观察骨骼肌肌纤维中的钙火花现象

钙火花(Ca^2 sparks)现象是近年来在骨骼肌、心肌兴奋收缩偶联研究中发现的重要生理现象，但目前确切的机制还不清楚。我们利用激光扫描共聚焦显微镜对经Flou-3AM染色的人工剥离的蟾蜍骨骼肌肌纤维进行连续扫描分析，在骨骼肌肌纤维中捕获到钙火花现象，并对钙火花现象的发生进行了初步探讨。     

Large-scale Models Reveal the Two-component Mechanics of Striated Muscle

This paper provides a comprehensive explanation of striated muscle mechanics and contraction on the basis of filament rotations. Helical proteins, particularly the coiled-coils of tropomyosin, myosin and α-actinin, shorten their H-bonds cooperatively and produce torque and filament rotations when the Coulombic net-charge repulsion of their highly charged side-chains is diminished by interaction with ions. The classical “two-component model” of active muscle differentiated a “contractile component” which stretches the “series elastic component” during force production. The contractile components are the helically shaped thin filaments of muscle that shorten the sarcomeres by clockwise drilling into the myosin cross-bridges with torque decrease (= force-deficit). Muscle stretch means drawing out the thin filament helices off the cross-bridges under passive counterclockwise rotation with torque increase (= stretch activation). Since each thin filament is anchored by four elastic α-actinin Z-filaments (provided with force-regulating sites for Ca²⁺ binding), the thin filament rotations change the torsional twist of the four Z-filaments as the “series elastic components”. Large scale models simulate the changes of structure and force in the Z-band by the different Z-filament twisting stages A, B, C, D, E, F and G. Stage D corresponds to the isometric state. The basic phenomena of muscle physiology, i. e. latency relaxation, Fenn-effect, the force-velocity relation, the length-tension relation, unexplained energy, shortening heat, the Huxley-Simmons phases, etc. are explained and interpreted with the help of the model experiments.     

Determination of in vivo rat muscle Gd-DTPA relaxivity at 6.3 T

For the in vivo relaxivity of Gd-DTPA at 6.3 T in rat muscle a value of 2.7±0.5 (mM s)⁻¹ was found, and for the in vitro value in water 3.00±0.56 (mM s)⁻¹ at 37°C. The temperature dependence of the in vitro relaxivity was −0.087 (mM s °C)⁻¹. The relation between1/T ₁ and the tissue Gd-DTPA concentration is linear for the normally used in vivo Gd-DTPA concentration range     

基于外侧腓肠肌sEMG的帕金森神经调控步态量化测评方法

帕金森(Parkinson's disease,PD)患者脑深部电刺激(deep brain stimulation,DBS)神经调控治疗迫切需要客观、量化的测评手段和分析方法.针对这一临床需求,本文提出一种基于外侧腓肠肌(lateral gastrocnemius,LG)表面肌电(surface electromyo...     

Antihypertensive Activities of Peptides Derived from Porcine Skeletal Muscle Myosin in Spontaneously Hypertensive Rats

ABSTRACT: Antihypertensive activities derived from porcine skeletal muscle proteins were investigated. Thermolysin hydrolysates of porcine muscle water-insoluble proteins demonstrated antihypertensive activities in spontaneously hypertensive rats when administrated in single oral doses. Hydrolysates of porcine myosin and peptides (Met-Asn-Pro-Pro-Lys, Ile-Thr-Thr-Asn-Pro, Met-Asn-Pro, Pro-Pro-Lys) with parts of the sequence of myosin showed antihypertensive activities. This is the first report of antihypertensive activities of peptides derived from muscle proteins of domestic animals. The hydrolysates of porcine muscle protein and their corresponding bioactive peptides might be utilized for physiologically functional foods.     

Stability of the physical properties of plasticized edible films from squid (Todarodes pacificus) mantle muscle during storage

Edible films from squid mantle muscle plasticized with different plasticizers were stored at 25 °C, 50% RH before the determination of physical properties. The results showed that tensile strength significantly increased (P < 0.05) upon the storage time, especially for the film plasticized with glucose, while there was no significant change (P ≥ 0.05) in elongation at break of all plasticized films. Water vapor permeability of glucose-plasticized film significantly decreased (P < 0.05) during storage, while there was only a slight change in those with glycerol, sorbitol, and fructose. Redness and yellowness of the films became significantly higher (P < 0.05) during storage, especially for the films plasticized with fructose and glucose. SDS-PAGE and protein solubility in SDS solution showed a possibility of protein aggregation throughout the storage. From these results, it is suggested that the changes in physical properties of the films were caused by the progress of Maillard reaction. PRACTICAL APPLICATION: In this study, squid mantle muscle was used as an edible film-forming material. By mixing with Na-citrate, squid mantle muscle possessed the ability to form transparent films with an excellent UV barrier property. Glycerol was found to be the most effective and stable plasticizer for the films. Edible films represent an option for the utilization of discarded squid during the fishing process.     

仿青蛙游动机器人机构设计

为研制仿青蛙游动机器人,设计了游动机器人机构.首先通过分析生物青蛙结构,设计仿青蛙机器人的原理样机.选择气动肌肉作为驱动器,分别驱动髋、膝、踝关节的转动,并采用钢丝传动结构,将膝关节气动肌肉安装在躯干上,从而有效减小了腿部的质量.建立了机器人系统的运动学模型并进行机器人运动学分析.分析了青蛙游动过程中的水下受力,并将水的作用力引入ADAMS仿真环境中,模拟了青蛙游动中的水环境,从而进行动力学仿真分析.最后对所研制出的仿青蛙游动机器人进行水下游动实验,其推进阶段平均速度达到339 mm/s.通过对比分析发现在动力学仿真和样机实验两种不同方法下机器人后肢运动形式基本一致,从而验证了仿青蛙游动机器人原理样机设计的可行性.     

微小气动机器人系统的模糊自适应PID控制

基于尺蠖的移动机理,研制了一种具有柔性移动机构的微小气动机器人内窥镜诊疗系统。描述了微机器人系统的本体结构和运动机理,并通过分析机器人系统的驱动力学特性和机器人的移动控制特性,给出了基于模糊自适应PID的气压-位置伺服控制方法,计算机仿真实验结果表明基于模糊自适应PID算法可实现机器人系统的有效控制。     

Factors affecting real-time evaluation of muscle function in smart rehab systems

Advancements in remote medical technologies and smart devices have led to expectations of contactless rehabilitation. Conventionally, rehabilitation requires clinicians to perform routine muscle function assessments with patients. However, assessment results are difficult to cross-reference owing to the lack of a gold standard. Thus, the application of remote smart rehabilitation systems is significantly hindered. This study analyzes the factors affecting the real-time evaluation of muscle function based on biometric sensor data so that we can provide a basis for a remote system. We acquired real clinical stroke patient data to identify the meaningful features associated with normal and abnormal musculature. We provide a system based on these emerging features that assesses muscle functionality in real time via streamed biometric signal data. A system view based on the amount of data, data processing speed, and feature proportions is provided to support the production of a rudimentary remote smart rehabilitation system.     

Surface characterization and catalytic properties of supported tungsten and platinum-tungsten carbide and oxycarbide

Bulk tungsten carbide has been prepared from ammonium paratungstate. Oxidic oxygen in relatively small amount is always present on the WC surface regardless of the method of carburization. Tungsten(VI) oxide in Al₂(WO₄)₃ can be reduced directly and in apparently one single step to the elemental W(0) state by Ar⁺ bombardment. Under H₂ the reduction starts at 720 K. In 12 and 28% W03 supported on -Al₂O₃ and in Al₂(WO₄)₃, almost 90% of the tungsten could be converted to the carbide form. Extensive hydrogenolysis products for n-hexane reactions on freshly prepared WC were observed while selectivity to isomerization associated with decrease in activity occurs upon exposure of the WC to oxygen at 620 K. Supported tungsten carbide(s) and oxycarbide(s) on -Al₂O₃ have comparable catalytic behaviour to those obtained on the bulk systems. The presence of Pt in these supported systems did not improve the catalytic performances and even did not show the catalytic properties of Pt. This was attributed to the severe conditions of catalyst preparations. Although the catalytic activity of tungsten carbide(s) obtained from the carburization of Al₂(WO₄)₃ is very low, the selectivity suggests the presence of tungsten carbide plus some WO, species.