PubMed Health⌕ Search

Biomedical subjects

F D Carlson

Publications and source records attributed to F D Carlson.

22 records · Page 2Linked to original sources
PubMed1969

Translational and rotational diffusion constants of tobacco mosaic virus from Rayleigh linewidths.

The translational and rotational diffusion constants of tobacco mosaic virus (TMV) have been determined from homodyne and heterodyne measurements of the spectrum of laser light scattered from dilute aqueous solutions of TMV. Our results for the translational and rotational constants respectively, reduced to 20 degrees C, are: D(T) = 0.280 +/- 0.006 x 10(-7) cm(2)/sec, and D(R) = 320 +/- 18 sec(-1). We include a theoretical derivation of the spectrum of light scattered from rod-shaped molecules which reproduces results obtained previously by Pecora, but which is specialized at the outset to the problem of dilute solutions so that simple single-particle correlation functions may be utilized. An analysis of the photocurrent spectrum for both the homodyne and heterodyne detection schemes is given. Various data reduction schemes utilized in the analysis of our spectra are described in some detail, and our results are compared with values of the diffusion constants obtained from other experiments.

Biophysical Phenomena↗
PubMed1967

The relation between heat produced and phosphorylcreatine split during isometric contraction of frog's muscle.

1. Heat production, tension development and phosphorylcreatine (PC) splitting have been measured simultaneously during isometric contractions of iodoacetate-poisoned frogs' sartorii at 0 degrees C. The muscles were stimulated to produce a series of 30 twitches or a 10 sec tetanus or a 30 sec tetanus.2. Of the several possible methods of calculating PC breakdown the best appears to be the one based on the assumption that PC/(total creatine) was originally the same in the two muscles of a pair.3. The difficulty of expressing PC break-down, heat production etc. in terms of the muscle's size is demonstrated.4. Several artifacts are discussed, including the heat produced by the stimulus and the possible role of reactions other than PC splitting.5. Even when these have been substantially eliminated there remains the rather intractable statistical problem of establishing a functional relationship between heat produced and PC split when both of these variables contain errors, so that ordinary regression analysis is misleading. It is shown that this problem can be dealt with satisfactorily by introducing other instrumental variables that can be determined experimentally.6. The final conclusion is that the in vivo enthalpy of hydrolysis of PC is about 10.6 kcal/mole, and is the same in twitches and in tetani.

Animals↗