A comparison of the hypoglycemic effect of insulin with systemic venous and portal venous administration

The hyperglycemic effect of insulin by prolonged intraportal and systemic infusion was measured in unanesthetized dogs with a modified portacaval transposition. There was no significant difference in response with the two routes of administration. The relation of these results to research directed to surgical therapy of diabetes is discussed. © 1963 W. B. Saunders Company

Grating Magneto-Optical Traps for Strontium

This thesis describes the construction of a new laboratory and a new apparatusfor ultracold strontium experiments. It also describes the the creation of the first strontium grating magneto-optical trap (MOT). The new strontium apparatus has been improved to provide high, and controllable atomic flux, high magnetic field coils, low vacuum pressure, plenty of optical access, and a streamlined computer control system. This flexible apparatus is designed to operate several potential experiments. Our work with strontium grating MOTs will help to enable the creation of compact, stable, and portable quantum devices that harness the unique capabilities of alkaline earth atoms. We present the construction of the grating MOT apparatus, the demonstration of the broad line strontium grating MOT, and the transfer to the narrow line grating MOT. In addition, we show the effectiveness of sawtooth wave adiabatic passage (SWAP) in the grating MOT geometry. Lastly, we present work from the previous apparatus, measuring the isotope shifts on the clock and intercombination transitions in strontium

The role of the convoluted segment of the proximal tubule in the disposal of 131 I-insulin in the rat kidney

It is generally accepted that in the kidney insulin is metabolized in the proximal tubule, but whether in the convoluted segment, the straight segment, or both has not been established. By means of autoradiography counting of radioactivity, and interrupted flow techniques, the following observations have been made. 131 I-labelled porcine insulin is metabolized exclusively in the convoluted segment of the proximal tubule. Although the glomerular filtrate is the major source of insulin supply to the renal epithelia, the peritubular capillary plexuses provide as much as 30% or more of the total insulin delivered to the renal epithelia. The epithelium of the convoluted segment is capable of sequestering 131 I-insulin from the peritubular capillary plexuses, a phenomenon which has not been established previously.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49671/1/1001400205_ftp.pd

Isotope-shift spectroscopy of the 1S0→3P1{^1}S_0 \rightarrow {^3}P_1 and 1S0→3P0{^1}S_0 \rightarrow {^3}P_0 transitions in strontium

Isotope shift spectroscopy with narrow optical transitions provides a benchmark for atomic structure calculations and has also been proposed as a way to constrain theories predicting physics beyond the Standard Model. Here, we have measured frequency shifts of the ${^1}S_0 \rightarrow {^3}P_1$ and ${^1}S_0 \rightarrow {^3}P_0$ transitions between all stable isotopes of strontium relative to ${^{88}}$Sr. This includes the first reported measurements of the ${^1}S_0 \rightarrow {^3}P_0$ isotope shift of ${^{88}}$Sr-${^{86}}$Sr and ${^{88}}$Sr-${^{84}}$Sr. Using the isotope shift measurements of the two transitions, a King plot analysis is performed. These results, combined with other recent isotope shift measurements in other atomic systems, will help refine atomic structure calculations and theoretical predictions for new physics.Comment: 9 pages, 4 figures, 3 table

Complete three-dimensional vector polarimetry with a Rydberg atom rf electrometer

Radio frequency (rf) receivers using Rydberg atoms offer appealing features over classical sensors, such as their size, frequency tuning range, and lack of field absorption. In this work, we extend the application space by demonstrating a Rydberg atom rf polarimeter. Using rf heterodyne with three independent and orthogonal local oscillators, we are able to extract the polarization ellipse of the field in three dimensions, in addition to the total amplitude of the field. We use the relative phases and amplitudes of the three generated heterodyne signals to measure the field amplitudes and phases along three cardinal axes giving the full three-dimensional polarization. We demonstrate this polarization measurement for incoming fields at different angles around the sensor. Lastly, we investigate the reception of data symbols encoded in the horizontal and vertical signal field polarizations and the phase between them. Our measurements yield an amplitude noise of 57 $\mu$V/m/$\sqrt{\text{Hz}}$ for horizontal polarization, 66 $\mu$V/m/$\sqrt{\text{Hz}}$ for vertical polarization, and a standard deviation of 0.094 rad in the phase between the field components.Comment: 10 pages, 6 figure

Geographic variation in sperm traits reflects predation risk and natural rates of multiple paternity in the guppy

Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape-limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high-predation populations had faster swimming sperm with longer midpieces compared to males in low-predation populations. However, we found no differences among males in high- and low-predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length