Fast component-by-component construction of lattice algorithms for multivariate approximation with POD and SPOD weights

The purpose of this study was to examine oxygen consumption (V˙o 2) and heart rate kinetics during moderate and repeated bouts of heavy square-wave cycling from an exercising baseline. Eight healthy, male volunteers performed square-wave bouts of leg ergometry above and below the gas exchange threshold separated by recovery cycling at 35%V˙o 2 peak.V˙o 2 and heart rate kinetics were modeled, after removal of phase I data by use of a biphasic on-kinetics and monoexponential off-kinetics model. Fingertip capillary blood was sampled 45 s before each transition for base excess, HCO[Formula: see text] and lactate concentration, and pH. Base excess and HCO[Formula: see text] concentration were significantly lower, whereas lactate concentration and pH were not different before the second bout. The results confirm earlier reports of a smaller mean response time in the second heavy bout. This was the result of a significantly greater fast-component amplitude and smaller slow-component amplitude with invariant fast-component time constant. A role for local oxygen delivery limitation in heavy exercise transitions with unloaded but not moderate baselines is presented.

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FAST AND SLOW COMPONENTS IN AXONAL TRANSPORT OF PROTEIN

The Journal of Cell Biology ◽

10.1083/jcb.38.3.494 ◽

1968 ◽

Vol 38 (3) ◽

pp. 494-508 ◽

Cited By ~ 270

Author(s):

Bruce S. McEwen ◽

Bernice Grafstein

Keyword(s):

Protein Synthesis ◽

Particulate Matter ◽

Optic Tectum ◽

Transport Mechanism ◽

Particulate Material ◽

Fast Component ◽

Retinal Protein ◽

Inhibition Of Protein Synthesis ◽

Optic Fibers ◽

Transported Material

(a) After injection of labeled leucine into the eye of goldfish, radioactive protein rapidly accumulates in the contralateral optic tectum in the layer containing the synaptic endings of the optic fibers. This material reaches the tectum 6–12 hr after the isotope injection, a fact which indicates that the rate of transport is at least 40 mm per day. (b) This rapidly transported material has been shown to consist exclusively of protein, in which the label remains attached to leucine. (c) Inhibition of protein synthesis in the retina prevents the appearance of the transported protein in the tectum, but inhibition of protein synthesis in the tectum does not. Substances having some of the same properties as leucine, such as cycloleucine and norepinephrine, are not transported to the tectum. These experiments all indicate that the transported protein is synthesized in the retina. However, inhibition of retinal protein synthesis after this protein has been formed does not interfere with the transport mechanism itself. (d) The fast component consists of about 85% particulate material. It may be distinguished from a slowly moving component, transported at 0.4 mm per day, which contains about 5 times as much radioactivity as the fast component, and which consists of 60% particulate matter and 40% soluble protein.

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