Nutritive Value of Powered Milk Together with Observations for a New Vitamin for Reproduction

Feeding experiments with rats revealed that the whole milk powder employed was adequate as a source of protein and vitamins for growth, reproduction, and rearing of young to the fourth generation. On similarly composed diets wherein skimmed milk powder (and butter fat) was employed in place of whole milk powder, there was marked interference with reproduction. Addition of either wheat embryo or yeast enhanced the nutritive value of the diet but did not make it optimum. Particularly, when added cod liver oil served as a source of some of the vitamins, decomposition products were observed when the diet was stored for a time. This suggests a possible deterioration of the diet as a result of the interaction of different components upon each other under these conditions. Certain added substances apparently retard this decomposition

Λ\Lambda-Enhanced Imaging of Molecules in an Optical Trap

We report non-destructive imaging of optically trapped calcium monofluoride (CaF) molecules using in-situ $\Lambda$-enhanced gray molasses cooling. $200$ times more fluorescence is obtained compared to destructive on-resonance imaging, and the trapped molecules remain at a temperature of $20\,\mu\text{K}$. The achieved number of scattered photons makes possible non-destructive single-shot detection of single molecules with high fidelity.Comment: 6 pages, 4 figure

Cod Liver Oil as a Source of Vitamin A

In the course of experiments having for their object the study of the properties of vitamin A with a view to its isolation, certain observations were made concerning the behavior of animals on various rations containing cod liver oil. It was noted that different samples of cod liver oil apparently vary markedly in vitamin A potency. Xerophthalmia has been produced in rats on diets containing as much as 3 per cent of cod liver oil. Synthetic rations containing cod liver oil evolve a penetrating odor resembling acrolein. When the cod liver oil is replaced with butter fat, this odor is not observed. It is possible that the failure of rats on diets containing certain samples of cod liver oil may be due to one or more of the following factors. 1. A decreased consumption of the diet clue to this decomposition product. 2. A destruction of vitamin A which runs parallel with the destruction of the cod liver oil. 3. Certain samples of cod liver oil are not as rich in vitamin A as supposed heretofore

Diet in Relation to Reproduction and Rearing of Young

Any information which aids in securing an answer to the question as to what constitutes an optimum diet is of the utmost importance. The employment of the biological method of investigation has been exceedingly fruitful of results in this field. By this method the diet is submitted to actual feeding tests with experimental animals and their behavior thereon is observed. For this purpose the rat is most frequently employed on account of its relatively small food consumption, its omniverous habit, and its comparatively short reproductive cycle and span of life. It is thus possible to get the life histories of these animals for several generations on a given diet in a comparatively short time. This is, moreover, a field of investigation in which the English speaking people are the acknowledged leaders. Instantly the names of Hopkins, Drummond, Osborne, Mendel, McCollum, Sherman, and others, are called to mind in connection with this line of work. Recognition and study of the substances designated vitamins have revealed relationships in nutrition hitherto unsuspected. It would have been quite impossible to disclose these newer fields of investigation by means of the usual methods of chemical experimentation

Observations on the Nutritive Value of Skimmed Milk Powder

Diets containing skim milk powder as the source of protein and vitamins other than A, produce results different from comparable diets made up from whole milk powder. Growth is about normal or may be better than normal. Reproduction and rearing of young is not normal. There are few or no litters, and the young almost invariably die. The period of producing the first litters may be much delayed. Addition of yeast or wheat embryo has resulted in normal growth and in the normal rearing of the first litters of young. The second generation rats are growing normally and appear to be in fine condition due to these supplements

Probing the helical content of growth hormone-releasing factor analogs using electrospray ionization mass spectrometry

AbstractA series of growth hormone-releasing factor analogs have been studied by both circular dichroism and electrospray ionization mass spectrometry (ESI/MS). The peptides are 32 residues long and are known to adopt a random-coil structure in aqueous solution but become increasing helical as the proportion of organic solvent is increased. Deuterium exchange was observed as an increase in mass of the peptide, as measured by ESI/MS. Rates of exchange were measured and half-lives calculated for analogs containing amino acid substitutions designed to promote or discourage helix formation. Exchange was slower in peptides that are helical (as shown by circular dichroism) than in randomly coiled peptides. Solution conditions that favor helix formation also produced slower exchange rates. These studies suggest that ESI/MS can provide date about the extent and stability of helix formation

One dimensional magneto-optical compression of a cold CaF molecular beam

We demonstrate with a RF-MOT the one dimensional, transverse magneto-optical compression of a cold beam of calcium monofluoride (CaF). By continually alternating the magnetic field direction and laser polarizations of the magneto-optical trap, a photon scattering rate of $2\pi \times$0.4 MHz is achieved. A 3D model for this RF-MOT, validated by agreement with data, predicts a 3D RF-MOT capture velocity for CaF of 5 m/s