427 research outputs found
The effects of stress on the blood calcium level in the male white rat (Rattus norvegicus)
THE EFFECTS OF STRESS ON THE BLOOD CALCIUM LEVEL IN THE MALE WHITE RAT (Rattus norvegicus) by Howard Perry Cobb I I I was writ ten as part of the requirements for a Master of Science degree in Biology at the University of Richmond (May, 1985). The present experiment was designed to determine whether parathyroid hormone (PTH) can be considered a stress hormone. Parathyroidectomized (PX) male rats (160-200 g) were injected with 10, 20, or 30 USP units of PTH per 100 g body weight and subjected to confinement/UHF stress for a 1.5-h period. Serum calcium levels of these PX groups were compared to sham-operated rats stressed in the same manner. Serum calcium levels of the stressed uninjected PX rats and those injected with 10 USP PTH dropped by 7.7% and 14.7% respectively whereas serum calcium levels of the PX+20 USP PTH dropped only by 3.3%. Serum calcium levels of the PX+30 USP PTH showed an increase similar to the sham-operated rats (5.2% and 7.0% respectively). These findings clearly demonstrate a role for PTH in the stress response
A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets
We present a targeted search for narrow-band (< 5 Hz) drifting sinusoidal
radio emission from 86 stars in the Kepler field hosting confirmed or candidate
exoplanets. Radio emission less than 5 Hz in spectral extent is currently known
to only arise from artificial sources. The stars searched were chosen based on
the properties of their putative exoplanets, including stars hosting candidates
with 380 K > T_eq > 230 K, stars with 5 or more detected candidates or stars
with a super-Earth (R_p 50 day orbit. Baseband voltage data
across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C.
Byrd Green Bank Telescope between Feb--Apr 2011 and subsequently searched
offline. No signals of extraterrestrial origin were found. We estimate that
fewer than ~1% of transiting exoplanet systems host technological civilizations
that are radio loud in narrow-band emission between 1-2 GHz at an equivalent
isotropically radiated power (EIRP) of ~1.5 x 10^21 erg s^-1, approximately
eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the the
number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the
Milky Way to be < 10^-6 M_solar^-1. Here we describe our observations, data
reduction procedures and results.Comment: Accepted to the Astrophysical Journa
Synthesis and Characterization of a Long-Acting Tenofovir ProTide Nanoformulation
Antiretroviral therapy (ART) has significantly improved the quality of life of Human Immunodeficiency Virus (HIV) patients; but adverse side effects and poor patient compliance to lifelong daily pills remain major challenges. To this end, the need for long acting (LA) therapies that can improve treatment adherence, positively affect drug resistance patterns in addition to limiting drug toxicities cannot be overstated. Tenofovir alafenamide (TAF), a nucleotide reverse transcriptase inhibitor of HIV infection and prodrug of tenofovir (TFV), is characterized by potent antiretroviral activities and high genetic barrier to viral resistance making it a suitable candidate for long-acting antiretroviral therapy. However, the inherent physicochemical features of TAF that includes high water solubility and susceptibility to degradation in aqueous buffers has limited its transformation into long-acting sustained release formulations. With these limitations in mind, this work sought to produce a stable TFV prodrug that would facilitate development of a long-acting formulation without compromising on TAF’s antiretroviral activity and safety profile. A lipophilic and hydrophobic prodrug of TFV (M1TFV) was therefore developed through chemical synthesis making it possible to formulate the drug as a stable aqueous nanosuspension to improve upon drug dissolution. The aqueous poloxamer stabilized TFV prodrug nanosuspension (NM1TFV) was characterized for physicochemical properties, chemical stability, cellular drug uptake and retention. The average particle size of the nanoparticles was 220-270 nm with a polydispersity index ofhttps://digitalcommons.unmc.edu/surp2021/1002/thumbnail.jp
Current and Nascent SETI Instruments
Here we describe our ongoing efforts to develop high-performance and
sensitive instrumentation for use in the search for extra-terrestrial
intelligence (SETI). These efforts include our recently deployed Search for
Extraterrestrial Emissions from Nearby Developed Intelligent Populations
Spectrometer (SERENDIP V.v) and two instruments currently under development;
the Heterogeneous Radio SETI Spectrometer (HRSS) for SETI observations in the
radio spectrum and the Optical SETI Fast Photometer (OSFP) for SETI
observations in the optical band. We will discuss the basic SERENDIP V.v
instrument design and initial analysis methodology, along with instrument
architectures and observation strategies for OSFP and HRSS. In addition, we
will demonstrate how these instruments may be built using low-cost, modular
components and programmed and operated by students using common languages, e.g.
ANSI C.Comment: 12 pages, 5 figures, Original version appears as Chapter 2 in "The
Proceedings of SETI Sessions at the 2010 Astrobiology Science Conference:
Communication with Extraterrestrial Intelligence (CETI)," Douglas A. Vakoch,
Edito
A report of dangerously high carbon monoxide levels within the passenger compartment of a snow-obstructed vehicle
BACKGROUND: We sought to determine how quickly carbon monoxide would accumulate in the passenger compartment of a snow-obstructed vehicle. METHODS: A 1992 sedan was buried in snow to the level of the undercarriage, the ignition was then engaged and carbon monoxide levels recorded at 2.5-minute intervals. The primary outcome was the time at which a lethal carbon monoxide level was detected. Six trials were conducted: windows closed; windows open one inch; windows open 6 inches; windows closed and tailpipe swept clear of snow; windows closed and one cubic foot of snow removed around tailpipe; windows closed and tailpipe completely cleared of snow to ground level in a path 12 inches wide. RESULTS: Lethal levels of carbon monoxide occurred within 2.5 minutes in the vehicle when the windows were closed, within 5 minutes when the widows were opened one inch, and within 7.5 minutes when the widows were opened six inches. Dangerously high levels of carbon monoxide were detected within the vehicle when the tailpipe had been swept clear of snow and when a one cubic foot area had been cleared around the tailpipe. When the tailpipe was completely unobstructed the carbon monoxide level was zero. CONCLUSIONS: Lethal levels of carbon monoxide occurred within minutes in this snow-obstructed vehicle
Status of the UC-Berkeley SETI Efforts
We summarize radio and optical SETI programs based at the University of
California, Berkeley. The SEVENDIP optical pulse search looks for ns time scale
pulses at visible wavelengths using an automated 30 inch telescope. The ongoing
SERENDIP V.v sky survey searches for radio signals at the 300 meter Arecibo
Observatory. The currently installed configuration supports 128 million
channels over a 200 MHz bandwidth with ~1.6 Hz spectral resolution. SETI@home
uses the desktop computers of volunteers to analyze over 160 TB of data at
taken at Arecibo looking for two types of continuous wave signals and two types
of pulsed signals. A version to be released this summer adds autocorrelation
analysis to look for complex wave forms that have been repeated (and overlayed)
after a short delay. SETI@home will soon be processing data of Kepler exoplanet
systems collected at the GBT. The Astropulse project is the first SETI search
for s time scale dispersed pulses in the radio spectrum. We recently
reobserved 114 sky locations where microsecond pulses were detected. This data
is in process of being transferred to Berkeley for analysis.Comment: 8 pages, including 1 figure. Presented at SPIE Conf. 8152, San Diego,
CA, Aug 25, 201
Current and Nascent SETI Instruments in the Radio and Optical
Here we describe our ongoing efforts to develop high-performance and sensitive instrumentation for use in the search for extra-terrestrial intelligence (SETI). These efforts include our recently deployed Search for Extraterrestrial Emissions from Nearby Developed Intelligent Populations Spectrometer (SERENDIP V.v) and two instruments currently under development; the Heterogeneous Radio SETI Spectrometer (HRSS) for SETI observations in the radio spectrum and the Optical SETI Fast Photometer (OSFP) for SETI observations in the optical band. We will discuss the basic SERENDIP V.v instrument design and initial analysis methodology, along with instrument architectures and observation strategies for OSFP and HRSS. In addition, we will demonstrate how these instruments may be built using low-cost, modular components and programmed and operated by students using common languages, e.g. ANSI C
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