Immediate Energy Sources in Muscle Contraction

Author(s):  
G. Mar�chal
Author(s):  
H. Mohri

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.


IEE Review ◽  
1991 ◽  
Vol 37 (4) ◽  
pp. 152
Author(s):  
Kenneth Spring

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1447-1452
Author(s):  
Vincent Mazauric ◽  
Ariane Millot ◽  
Claude Le Pape-Gardeux ◽  
Nadia Maïzi

To overcome the negative environemental impact of the actual power system, an optimal description of quasi-static electromagnetics relying on a reversible interpretation of the Faraday’s law is given. Due to the overabundance of carbon-free energy sources, this description makes it possible to consider an evolution towards an energy system favoring low-carbon technologies. The management for changing is then explored through a simplified linear-programming problem and an analogy with phase transitions in physics is drawn.


2019 ◽  
Vol 5 (1) ◽  
pp. 35-45
Author(s):  
Markus Dwiyanto Tobi ◽  
Alimuddin Mappa

The role of the power supply device is to produce, process and distribute energy sources. Telecommunication equipment can only operate if it has continuous supply. Therefore, to maintain the continuity of the supply, a UPS (Uninterruptable Power Supply) device system is needed so that the supply to the Essential Load device will remain available so that continuity will be maintained. This research designs and proposes how a series of automatic redundant switch systems on UPS to ensure the availability of power supply for the main equipment of telecommunications systems. The Auto switch circuit is designed to have 3 (three) working stages which will trigger the relay driver as control circuit, namely the normal working condition of the contactor input K1 is present, the input condition is zero (lost), and the input condition is present. This system can automatically supply power to telecommunications equipment.


2020 ◽  
Vol 1 (2) ◽  
pp. 189-193
Author(s):  
Aisha Naiga ◽  
Loyola Rwabose Karobwa

Over 90% of Uganda's power is generated from renewable sources. Standardised Implementation Agreements and Power Purchase Agreements create a long-term relationship between Generating Companies and the state-owned off-taker guaranteed by Government. The COVID-19 pandemic and measures to curb the spread of the virus have triggered the scrutiny and application of force majeure (FM) clauses in these agreements. This article reviews the FM clauses and considers their relevance. The authors submit that FM clauses are a useful commercial tool for achieving energy justice by ensuring the continuity of the project, despite the dire effects of the pandemic. Proposals are made for practical considerations for a post-COVID-19 future which provides the continued pursuit of policy goals of promoting renewable energy sources and increasing access to clean energy, thus accelerating just energy transitions.


1985 ◽  
Vol 146 (6) ◽  
pp. 348
Author(s):  
E.R. Mustel' ◽  
V.E. Chertoprud ◽  
N.B. Mulyukova
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