Helicopter transmission research at NASA Lewis Research Center

A joint helicopter transmission research program between NASA Lewis Research Center and the U.S. Army Aviation Systems Command has existed since 1970. Program goals are to reduce weight and noise and to increase life and reliability. Reviewed are significant advances in technology for gears and transmissions and the experimental facilities at NASA Lewis for helicopter transmission testing are described. A description of each of the rigs is presented along with some significant results from the experiments

The signal peptide of pro-opiomelancortin: Validation of a specific radioimmunoassay

The N-terminus portion of the POMC leader sequence (signal peptide) was synthesized, and an antiserum was raised against it. A radioimmunoassay was developed which is effective at a dilution of 1:500,000, and sensitive at less than 1 fmole/tube. Since leader sequences often exhibit structural homologies, and since synthetic peptides are not readily available, we resorted to an unusual procedure to establish specificity. This involved extraction of pituitary RNA, cell-free translation to produce the pre-prohormones, and purification by B-END and signal antibody affinity columns. The eluates were then tested by SDS gel electrophoresis and by multiple immunoprecipitations. All results showed that the signal antibody captured a single molecular species, approximately 30,000 in MW, which was also captured by the B-END column, and was immunoprecipitable by B-END and ACTH antisera. It therefore appears that this antibody selectively measures the POMC leader sequence and should be valuable in measuring the newly synthesized pre-prohormone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23804/1/0000042.pd

Dynorphin is located throughout the CNS and is often co-localized with alpha-neo-endorphin

The opioid peptide dynorphin has been described as widely distributed in CNS when measured by RIA. Our previous immunohistochemical studies have only demonstrated dynorphin cells as those containing AVP. We now report the specific localization of dynorphin throughout the neuraxis. Further, dynorphin and alpha-neo-endorphin have been co-localized to the same magnocellular neurosecretory cells in hypothalamus. We report agreement with the findings of others and extend them to include a cell group in dorsomedial hypothalmus, further strengthening the association between dynorphin and alpha-neo-endorphin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23834/1/0000073.pd

Des-tyrosine-dynorphin antagonizes morphine analgesia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23809/1/0000047.pd

Dynorphin immunocytochemistry in the rat central nervous system

The distribution of dynorphin in the central nervous system was investigated in rats pretreated with relatively high doses (300-400 [mu]g) of colchicine administered intracerebroventricularly. To circumvent the problems of antibody cross-reactivity, antisera were generated against different portions as well as the full dynorphin molecule (i.e., residues 1-13, 7-17, or 1-17). For comparison, antisera to [Leu]enkephalin (residues 1-5) were also utilized. Dynorphin was found to be widely distributed throughout the neuraxis. Immunoreactive neuronal perikarya exist in hypothalamic magnocellular nuclei, periaqueductal gray, scattered reticular formation sites, and other brain stem nuclei, as well as in spinal cord. Additionally, dynorphin-positive fibers or terminals occur in the cerebral cortex, olfactory bulb, nucleus accumbens, caudate-putamen, globus pallidus, hypothalamus, substantia nigra, periaqueductal gray, many brain stem sties, and the spinal cord. In many areas studied, dynorphin and enkephalin appeared to form parallel but probably separate anatomical systems. The results suggest that dynorphin occurs in neuronal systems that are immunocytochemically distinct from those containing other opioid peptides.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23823/1/0000062.pd

Analysis of Neptune's 2017 Bright Equatorial Storm

We report the discovery of a large ($\sim$8500 km diameter) infrared-bright storm at Neptune's equator in June 2017. We tracked the storm over a period of 7 months with high-cadence infrared snapshot imaging, carried out on 14 nights at the 10 meter Keck II telescope and 17 nights at the Shane 120 inch reflector at Lick Observatory. The cloud feature was larger and more persistent than any equatorial clouds seen before on Neptune, remaining intermittently active from at least 10 June to 31 December 2017. Our Keck and Lick observations were augmented by very high-cadence images from the amateur community, which permitted the determination of accurate drift rates for the cloud feature. Its zonal drift speed was variable from 10 June to at least 25 July, but remained a constant $237.4 \pm 0.2$ m s$^{-1}$ from 30 September until at least 15 November. The pressure of the cloud top was determined from radiative transfer calculations to be 0.3-0.6 bar; this value remained constant over the course of the observations. Multiple cloud break-up events, in which a bright cloud band wrapped around Neptune's equator, were observed over the course of our observations. No "dark spot" vortices were seen near the equator in HST imaging on 6 and 7 October. The size and pressure of the storm are consistent with moist convection or a planetary-scale wave as the energy source of convective upwelling, but more modeling is required to determine the driver of this equatorial disturbance as well as the triggers for and dynamics of the observed cloud break-up events.Comment: 42 pages, 14 figures, 6 tables; Accepted to Icaru

Dynorphin (1-17): Lack of analgesia but evidence for non-opiate electrophysiological and motor effects

Dynorphin and an opiate-inactive fragment des-Tyr-dynorphin produced similar effects on EEG, motor function and hippocampal unit firing. Naloxone had no effect on the actions of dynorphin in these systems and dynorphin failed to produce analgesia upon central administration. These results suggest that dynorphin has a pharmacological character that differs significantly from the classic narcotics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23835/1/0000074.pd

[D-Ala2,(F5)Phe4]-dynorphin1-13-NH2 (DAFPHEDYN): A potent analog of dynorphin 1-13

Intracerebroventricular administration of the dynorphin analog, [D-Ala2,(F5)Phe4]-dynorphin1-13-NH2 (DAFPHEDYN) in rats produced diuresis and profound analgesia. Both effects were antagonized by central administration of naltrexone or naloxone. Intravenous administration of 10, 25, and 50 mg/kg of DAFPHEDYN failed to induce diuresis. The increased potency of DAFPHEDYN was apparent from the failure of an equal dose of the parent compound (dynorphin 1-13) to produce diuresis and the failure of [D-Ala2]-dynorphin1-13-NH2 to produce analgesia. Radioligand binding studies indicated the DAFPHEDYN retains the same degree of [kappa] selectivity as the parent compound (dynorphin 1-13) though a drop in affinity occurred. DAFPHEDYN may be of significant interest because it retains the essential pharmacology of the parent compound and exhibits marked in vivo potency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26600/1/0000141.pd