691 research outputs found
Simulation of fluid flows during growth of organic crystals in microgravity
Several counter diffusion type crystal growth experiments were conducted in space. Improvements in crystal size and quality are attributed to reduced natural convection in the microgravity environment. One series of experiments called DMOS (Diffusive Mixing of Organic Solutions) was designed and conducted by researchers at the 3M Corporation and flown by NASA on the space shuttle. Since only limited information about the mixing process is available from the space experiments, a series of ground based experiments was conducted to further investigate the fluid dynamics within the DMOS crystal growth cell. Solutions with density differences in the range of 10 to the -7 to 10 to the -4 power g/cc were used to simulate microgravity conditions. The small density differences were obtained by mixing D2O and H2O. Methylene blue dye was used to enhance flow visualization. The extent of mixing was measured photometrically using the 662 nm absorbance peak of the dye. Results indicate that extensive mixing by natural convection can occur even under microgravity conditions. This is qualitatively consistent with results of a simple scaling analysis. Quantitave results are in close agreement with ongoing computational modeling analysis
Acromegaly and Cushing's syndrome caused by a neuroendocrine tumor arising within a sacrococcygeal teratoma.
A 60-year-old man with a pre-existing stable sacrococcygeal teratoma developed acromegaly, ectopic Cushing's syndrome, and 5HIAA secretion. To our knowledge, this represents the first reported case of ACTH and serotonin secretion, and likely GHRH or GH cosecretion, from a sacrococcygeal teratoma in an adult
MOVEABLE, DEPLOYABLE MICROGRID ANALYSIS
This report focuses on the assessment of the feasibility of Moveable, Deployable Microgrids (MODEMs) from an interoperability and sustainment perspective as an alternative solution to traditional backup power methods aimed at bringing critical loads back online after installation microgrid failures or operational energy needs. Prior research into microgrid solutions by MAJ Daniel Varley in his paper “Feasibility Analysis of a Mobile Microgrid Design to Support Department of Defense (DOD) Energy Resilience Goals” identified MODEM as a potential solution. This report utilized the work done by MAJ Varley and further assesses system feasibility.
Base and operational energy managers will benefit from MODEMs by having access to multi-energy source systems that are both easily moveable and relatively simplistic in design. As concerns surrounding energy resiliency of defense critical infrastructure by both the DOD and Department of Energy (DOE) mount, as expressed in a March 2022 report by the Electricity Advisory Committee (EAC) titled “Strengthening the Resilience of Defense Critical Infrastructure”, there is a push to identify cost-effective solutions that utilize alternative energy sources in order to improve the overall resiliency of this infrastructure. The MODEM system has the potential to be a viable solution to the resiliency problem.Outstanding ThesisCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited
Immunomodulation and T Helper TH1/TH2 Response Polarization by CeO2 and TiO2 Nanoparticles
Immunomodulation by nanoparticles, especially as related to the biochemical properties of these unique materials, has scarcely been explored. In an in vitro model of human immunity, we demonstrate two catalytic nanoparticles, TiO2 (oxidant) and CeO2 (antioxidant), have nearly opposite effects on human dendritic cells and T helper (T-H) cells. For example, whereas TiO2 nanoparticles potentiated DC maturation that led towards T(H)1-biased responses, treatment with antioxidant CeO2 nanoparticles induced APCs to secrete the anti-inflammatory cytokine, IL-10, and induce a T(H)2-dominated T cell profile. In subsequent studies, we demonstrate these results are likely explained by the disparate capacities of the nanoparticles to modulate ROS, since TiO2, but not CeO2 NPs, induced inflammatory responses through an ROS/inflammasome/IL-1 beta pathway. This novel capacity of metallic NPs to regulate innate and adaptive immunity in profoundly different directions via their ability to modulate dendritic cell function has strong implications for human health since unintentional exposure to these materials is common in modern societies
Immunomodulation and T Helper TH1/TH2 Response Polarization by CeO2 and TiO2 Nanoparticles
Immunomodulation by nanoparticles, especially as related to the biochemical properties of these unique materials, has scarcely been explored. In an in vitro model of human immunity, we demonstrate two catalytic nanoparticles, TiO2 (oxidant) and CeO2 (antioxidant), have nearly opposite effects on human dendritic cells and T helper (T-H) cells. For example, whereas TiO2 nanoparticles potentiated DC maturation that led towards T(H)1-biased responses, treatment with antioxidant CeO2 nanoparticles induced APCs to secrete the anti-inflammatory cytokine, IL-10, and induce a T(H)2-dominated T cell profile. In subsequent studies, we demonstrate these results are likely explained by the disparate capacities of the nanoparticles to modulate ROS, since TiO2, but not CeO2 NPs, induced inflammatory responses through an ROS/inflammasome/IL-1 beta pathway. This novel capacity of metallic NPs to regulate innate and adaptive immunity in profoundly different directions via their ability to modulate dendritic cell function has strong implications for human health since unintentional exposure to these materials is common in modern societies
Inflammation in benign prostate tissue and prostate cancer in the finasteride arm of the Prostate Cancer Prevention Trial
BACKGROUND: A previous analysis of the placebo arm of the Prostate Cancer Prevention Trial (PCPT) reported 82% overall prevalence of intraprostatic inflammation and identified a link between inflammation and higher-grade prostate cancer and serum PSA. Here we studied these associations in the PCPT finasteride arm. METHODS: Prostate cancer cases (N=197) detected either on a clinically indicated biopsy or on protocol-directed end-of-study biopsy, and frequency-matched controls (N=248) with no cancer on an end-of-study biopsy were sampled from the finasteride arm. Inflammation in benign prostate tissue was visually assessed using digital images of H&E stained sections. Logistic regression was used for statistical analysis. RESULTS: In the finasteride arm, 91.6% of prostate cancer cases and 92.4% of controls had at least one biopsy core with inflammation in benign areas; p < 0.001 for difference compared to placebo arm. Overall, the odds of prostate cancer did not differ by prevalence (OR=0.90, 95% CI 0.44-1.84) or extent (P-trend=0.68) of inflammation. Inflammation was not associated with higher-grade disease (prevalence: OR=1.07, 95% CI 0.43-2.69). Furthermore, mean PSA concentration did not differ by the prevalence or extent of inflammationin either cases or controls. CONCLUSION: The prevalence of intraprostatic inflammation was higher in the finasteride than placebo arm of the PCPT, with no association with higher-grade prostate cancer. IMPACT: Finasteride may attenuate the association between inflammation and higher-grade prostate cancer. Moreover, the missing link between intraprostatic inflammation and PSA suggests that finasteride may reduce inflammation-associated PSA elevation
Communications Biophysics
Contains reports on five research projects.National Institutes of Health (Grant 5 PO1 GM14940-03)Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)National Aeronautics and Space Administration (Grant NGL 22-009-304
Low False-Positive Rate of Kepler Candidates Estimated From A Combination Of Spitzer And Follow-Up Observations
(Abridged) NASA's Kepler mission has provided several thousand transiting
planet candidates, yet only a small subset have been confirmed as true planets.
Therefore, the most fundamental question about these candidates is the fraction
of bona fide planets. Estimating the rate of false positives of the overall
Kepler sample is necessary to derive the planet occurrence rate. We present the
results from two large observational campaigns that were conducted with the
Spitzer telescope during the the Kepler mission. These observations are
dedicated to estimating the false positive rate (FPR) amongst the Kepler
candidates. We select a sub-sample of 51 candidates, spanning wide ranges in
stellar, orbital and planetary parameter space, and we observe their transits
with Spitzer at 4.5 microns. We use these observations to measures the
candidate's transit depths and infrared magnitudes. A bandpass-dependent depth
alerts us to the potential presence of a blending star that could be the source
of the observed eclipse: a false-positive scenario. For most of the candidates
(85%), the transit depths measured with Kepler are consistent with the depths
measured with Spitzer as expected for planetary objects, while we find that the
most discrepant measurements are due to the presence of unresolved stars that
dilute the photometry. The Spitzer constraints on their own yield FPRs between
5-40%, depending on the KOIs. By considering the population of the Kepler field
stars, and by combining follow-up observations (imaging) when available, we
find that the overall FPR of our sample is low. The measured upper limit on the
FPR of our sample is 8.8% at a confidence level of 3 sigma. This observational
result, which uses the achromatic property of planetary transit signals that is
not investigated by the Kepler observations, provides an independent indication
that Kepler's false positive rate is low.Comment: 33 pages, 16 figures, 3 tables; accepted for publication in ApJ on
February 7, 201
Mars Aeronomy Observer: Report of the Science Working Team
The Mars Aeronomy Observer (MAO) is a candidate follow-on mission to Mars Observer (MO) in the Planetary Observer Program. The four Mariner and two Viking spacecraft sent to Mars between 1965 and 1976 have provided a wealth of information concerning Martian planetology. The Mars Observer, to be launched in 1990, will build on their results by further examining the elemental and mineralogical composition of the surface, the strength and multipolar composition of the planetary magnetic field, the gravitational field and topography, and the circulation of the lower atmosphere. The Mars Aeronomy Observer is intended to address the last major aspects of Martian environment which have yet to be investigated: the upper atmosphere, the ionsphere, and the solar wind interaction region
The atmospheres of the hot-Jupiters Kepler-5b and Kepler-6b observed during occultations with Warm-Spitzer and Kepler
This paper reports the detection and the measurements of occultations of the
two transiting hot giant exoplanets Kepler-5b and Kepler-6b by their parent
stars. The observations are obtained in the near infrared with Spitzer Space
Telescope and at optical wavelengths by combining more than a year of Kepler
photometry. The investigation consists of constraining the eccentricities of
these systems and of obtaining broad band emergent spectra for individual
planets. For both targets, the occultations are detected at 3 sigma level at
each wavelength with mid-occultation times consistent with circular orbits. The
brightness temperatures of these planets are deduced from the infrared
observations and reach T=1930+/-100K and T=1660+/-120K for Kepler-5b and
Kepler-6b respectively. We measure optical geometric albedos A_g in the Kepler
bandpass and find A_g=0.12+/-0.04 for Kepler-5b and A_g=0.11+/-0.04 for
Kepler-6b leading to an upper limit for the Bond albedo of A_B < 0.17 in both
cases. The observations for both planets are best described by models for which
most of the incident energy is redistributed on the dayside, with only less
than 10% of the absorbed stellar flux redistributed to the night side of these
planets. The data for Kepler-5b favor a model without a temperature inversion,
whereas for Kepler-6b they do not allow distinguishing between models with and
without inversion.Comment: 26 pages, 18 figures, 3 tables, submitted to Ap
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