Skeletal muscles are composed of fibres of different types, each type being identified by the isoform of myosin heavy chain which is expressed as slow 1, fast 2A, fast 2X, and fast 2B. Slow fibres are resistant to fatigue due to their highly oxidative metabolism whereas 2X and 2B fibres are easily fatiguable and fast 2A fibres exhibit intermediate fatigue resistance. Slow fibres and fast fibres...

Sheets of muscle fibres dissected from surface portions of frog ileofibularis and semitendinosus muscles were soaked in solutions with elevated K and Cl concentrations. The KCl-loaded muscles were then bathed in low [Cl-] solutions, whereby the membrane potential became transiently inside positive. The repolarization of the twitch fibres from the tonus bundle ("intermediate fibres") was faster ...

OBJECTIVE The objective of the study was measurement of the concentrations of airborne asbestos fibres in the rural environment of the Lublin Region in south-east Poland. METHODS Measurements of concentrations of respirable asbestos fibres were carried out in the rural areas of the Lublin Region (Lublin and Włodawa counties) for a period of 24 months. The studies were conducted on 3 farms wit...

Characteristics of the anion conductance of muscle fibres from green sunfish have been determined. The membrane conductance of fibres from sunfish acclimated to 25 and 7 degrees C was linearly related to the extracellular chloride concentration. The chloride conductance exhibited a pH dependence which was adequately described by the titration of an acidic site with a pKa of 5.3 in 25 degrees C-...

Washing clothes made from synthetic materials has been identified as a potentially important source of microscopic fibres to the environment. This study examined the release of fibres from polyester, polyester-cotton blend and acrylic fabrics. These fabrics were laundered under various conditions of temperature, detergent and conditioner. Fibres from waste effluent were examined and the mass, a...

An immunocytochemical study was conducted on elastic components in the sclera of seven aged human eyes. By conventional electron microscopy, elastic tissue consists of three distinct fibre types--elastic fibres, elaunin fibres, and oxytalan fibres. The distribution of six components associated with the elastic system (elastin, amyloid P component, laminin, fibronectin, gp 115, and vitronectin) ...

Single white fibres and small bundles (two to three) of red fibres were isolated from the trunk muscle of Pacific Blue Marlin (50-121 kg body weight). Fibres were chemically skinned with 1% Brij. Maximum Ca2+-activated force production (Po) was 57 kN m-2 for red fibres and 176 kN m-2 for white fibres at 25 degrees C. The force-velocity (P-V) characteristics of these fibres were determined at 15...

This study investigated for the first time maximum force production, shortening velocity (Vmax) and power output in permeabilised single muscle fibres at 12°C from lion, Panthera leo (Linnaeus 1758), and caracal, Caracal caracal (Schreber 1776), and compared the values with those from human cyclists. Additionally, the use and validation of previously frozen tissue for contractile experiments is...

Polyacrylonitrile (PAN)and pitch-based carbon fibres are widely used as a reinforcement in composite materials such as carbon fibre reinforced plastics, carbon fibre reinforced ceramics, carbon-carbon composites and carbon fibre reinforced metals, because of their high specific strength and modulus. Such composites have become a dominant material in the aerospace, automotive and sporting goods ...

1. The thermal dependence of passive electrical properties was determined for twitch fibres from the white region of the iliofibularis (IF) muscle of Anolis cristatellus (15-35 degrees C) and Sceloporus occidentalis (15-40 degrees C), and for twitch fibres from the white (15-45 degrees C) and red (15-40 degrees C) regions of the IF of Dipsosaurus dorsalis. These species differ in thermal ecolog...