Further Studies of the Self-Induced Translation Model of Myosin Head Motion Along the Actin Filament

1993 ◽  
pp. 377-387
Author(s):  
Toshio Mitsui ◽  
Hiroyuki Ohshima
Keyword(s):  
Actin Filament ◽  
Myosin Head ◽  
The Self ◽  
Head Motion ◽  
Translation Model

Proposed Modification of the Huxley—Simmons Model for Myosin Head Motion along an Actin Filament

1996 ◽  
Vol 182 (2) ◽  
pp. 147-159 ◽  
Author(s):  
Toshio Mitsui ◽  
Hisahiro Chiba
Keyword(s):  
Actin Filament ◽  
Myosin Head ◽  
Head Motion ◽  
Proposed Modification

scholarly journals A Single Myosin Head Moves along an Actin Filament with Regular Steps during One Biochemical Cycle of ATP Hydrolysis

2000 ◽  
Vol 40 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Kazuo KITAMURA ◽  
Atsuko H. IWANE ◽  
Makio TOKUNAGA
Keyword(s):  
Actin Filament ◽  
Atp Hydrolysis ◽  
Myosin Head

scholarly journals Mechanical model of muscle contraction 2. Kinematic and dynamic aspects of a myosin II head during the working stroke

2019 ◽  
Author(s):  
S. Louvet
Keyword(s):  
Actin Filament ◽  
Myosin Head ◽  
Myosin Ii ◽  
Tangential Force ◽  
Longitudinal Axis ◽  
Myosin Filament ◽  
Analytical Relationship ◽  
Shortening Velocity ◽  
Fixed Plane ◽  
Algorithmic Optimization

AbstractThe condition of a myosin II head during which force and movement are generated is commonly referred to as Working Stroke (WS). During the WS, the myosin head is mechanically modelled by 3 two by two articulated segments, the motor domain (S1a) strongly fixed to an actin molecule, the lever (S1b) on which a motor moment is exerted, and the rod (S2) pulling the myosin filament (Mfil). When the half-sarcomere (hs) is shortened or lengthened by a few nanometers, it is assumed that the lever of a myosin head in WS state moves in a fixed plane including the longitudinal axis of the actin filament (Afil). As a result, the 5 rigid segments, i.e. Afil, S1a, S1b, S2 and Mfil, follow deterministic and configurable trajectories. The orientation of S1b in the fixed plane is characterized by the angle θ. After deriving the geometric equations singularizing the WS state, we obtain an analytical relationship between the hs shortening velocity (u) and the angular velocity of the lever . The principles of classical mechanics applied to the 3 solids, S1a, S1b and S2, lead to a relationship between the motor moment exerted on the lever (MB) and the tangential force dragging the actin filament (TA). We distinguish θup and θdown, the two boundaries framing the angle θ during the WS, relating to up and down conformations. With the usual data assigned to the cross-bridge elements, a linearization procedure of the relationships between u and , on the one hand, and between MB and TA, on the other hand, is performed. This algorithmic optimization leads to theoretical values of θup and θdown equal to +28° (−28°) and −42° (+42°) respectively with a variability of ±5° in a hs on the right (left), data in accordance with the commonly accepted experimental values for vertebrate muscle fibers.

scholarly journals English Machine Translation Model Based on an Improved Self-Attention Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenxia Pan
Keyword(s):  
Machine Translation ◽  
Language Processing ◽  
Extraction Methods ◽  
Attention Mechanism ◽  
The Self ◽  
Position Information ◽  
Directional Information ◽  
Translation Model ◽  
Model Based ◽  
Phrase Extraction

English machine translation is a natural language processing research direction that has important scientific research value and practical value in the current artificial intelligence boom. The variability of language, the limited ability to express semantic information, and the lack of parallel corpus resources all limit the usefulness and popularity of English machine translation in practical applications. The self-attention mechanism has received a lot of attention in English machine translation tasks because of its highly parallelizable computing ability, which reduces the model’s training time and allows it to capture the semantic relevance of all words in the context. The efficiency of the self-attention mechanism, however, differs from that of recurrent neural networks because it ignores the position and structure information between context words. The English machine translation model based on the self-attention mechanism uses sine and cosine position coding to represent the absolute position information of words in order to enable the model to use position information between words. This method, on the other hand, can reflect relative distance but does not provide directionality. As a result, a new model of English machine translation is proposed, which is based on the logarithmic position representation method and the self-attention mechanism. This model retains the distance and directional information between words, as well as the efficiency of the self-attention mechanism. Experiments show that the nonstrict phrase extraction method can effectively extract phrase translation pairs from the n-best word alignment results and that the extraction constraint strategy can improve translation quality even further. Nonstrict phrase extraction methods and n-best alignment results can significantly improve the quality of translation translations when compared to traditional phrase extraction methods based on single alignment.

scholarly journals Dual contextual module for neural machine translation

2021 ◽  
Author(s):  
Isaac Kojo Essel Ampomah ◽  
Sally McClean ◽  
Glenn Hawe
Keyword(s):  
Machine Translation ◽  
Contextual Information ◽  
Attention Mechanism ◽  
The Self ◽  
Experimental Results ◽  
Neural Machine Translation ◽  
Translation Model ◽  
Global Context ◽  
Overall Performance ◽  
Transformer Model

AbstractSelf-attention-based encoder-decoder frameworks have drawn increasing attention in recent years. The self-attention mechanism generates contextual representations by attending to all tokens in the sentence. Despite improvements in performance, recent research argues that the self-attention mechanism tends to concentrate more on the global context with less emphasis on the contextual information available within the local neighbourhood of tokens. This work presents the Dual Contextual (DC) module, an extension of the conventional self-attention unit, to effectively leverage both the local and global contextual information. The goal is to further improve the sentence representation ability of the encoder and decoder subnetworks, thus enhancing the overall performance of the translation model. Experimental results on WMT’14 English-German (En$$\rightarrow $$ → De) and eight IWSLT translation tasks show that the DC module can further improve the translation performance of the Transformer model.

Actomyosin interaction in striated muscle

1997 ◽  
Vol 77 (3) ◽  
pp. 671-697 ◽  
Author(s):  
R. Cooke
Keyword(s):  
Actin Filament ◽  
Striated Muscle ◽  
Myosin Head ◽  
Three Dimensional ◽  
Step Length ◽  
Myosin Molecule ◽  
Actin Monomer ◽  
Active Fiber ◽  
Actomyosin Interaction ◽  
Dimensional Crystal

The mechanics of the actomyosin interaction have been extensively studied using the organized filament array of striated muscle. However, the extrapolation of these data to the events occurring at the level of a single actomyosin interaction has not been simple. Problems arise in part because an active fiber has an ensemble of myosin heads that are spread out through the various steps of the active cycle, and it is likely that only a small fraction of the heads are generating tension at any given time. More recently, two new approaches have greatly extended our knowledge of the actomyosin interaction. First, the three-dimensional crystal structures of both the actin monomer and the myosin head have been determined, and these structures have been fit to lower resolution images to give atomic models of the actin filament and of the actin filament decorated by myosin heads. Second, the technology to measure picoNewton forces and nanometer distances has provided direct determinations of the force and step length generated by a single myosin molecule interacting with a single actin filament. This review synthesizes the existing mechanical data obtained from the more-organized array of the muscle filament with the results obtained by these two technologies.

A single myosin head moves along an actin filament with regular steps of 5.3 nanometres

Nature ◽  
10.1038/16403 ◽  
1999 ◽  
Vol 397 (6715) ◽  
pp. 129-134 ◽  
Author(s):  
Kazuo Kitamura ◽  
Makio Tokunaga ◽  
Atsuko Hikikoshi Iwane ◽  
Toshio Yanagida
Keyword(s):  
Actin Filament ◽  
Myosin Head
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