292 research outputs found
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Repeatable approaches to work with scientific uncertainty and advance climate change adaptation in US national parks
Integrated analysis of topographically high Mafic exposures at Apollo-17 landing site using data from imaging sensors of Chandrayaan-1
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Curie: Constraining Solar System Bombardment Using In Situ Radiometric Dating
The Curie mission would constrain the existence of the putative cataclysm by determining the age of samples directly sourced from the impact melt sheet of a major pre-Imbrium lunar basin. The measurements would also enable further understanding of lunar evolution by characterizing new lunar lithologies far from the Apollo and Luna landing sites, including the very low-Ti basalts in Mare Crisium and potential olivine rich lithologies in the margins of both Mare Nectaris and Mars Crisium. Equipped with a mass spectrometer and a LIBS, Curie would also be well-placed to survey volatile components of the lunar regolith, including surface-bound hydrogen
Two Regional Mental Health Treatment Facilities
One of the major social programs of the 1960s was the development of community mental health centers. As with most early attempts at evaluation, the results were pessimistic. This article reanalyzes one of the earliest, and best-known, evaluations of a community-based treatment facility. Following the conceptual framework of Campbell and his associates, it was found that the various threats to the validity of the findings indicate a consistent and systematic bias against detecting a positive effect for the new mental health center. In light of recent federal legislation mandating formal evaluations, appropriate procedures are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68090/2/10.1177_0193841X7900300403.pd
Enhanced Bioactivity of silybin B methylation Products
Abstract: Flavonolignans from milk thistle (Silybum marianum) have been investigated for their cellular modulatory properties, including cancer chemoprevention and hepatoprotection, as an extract (silymarin), as partially purified mixtures (silibinin and isosilibinin), and as pure compounds (a series of seven isomers). One challenge with the use of these compounds in vivo is their relatively short half-life due to conjugation, particularly glucuronidation. In an attempt to generate analogues with improved in vivo properties, particularly reduced metabolic liability, a semi-synthetic series was prepared in which the hydroxy groups of silybin B were alkylated. A total of five methylated analogues of silybin B were synthesized using standard alkylation conditions (dimethyl sulfate and potassium carbonate in acetone), purified using preparative HPLC, and elucidated via spectroscopy and spectrometry. Of the five, one was monomethylated (3), one was dimethylated (4), two were trimethylated (2 and 6), and one was tetramethylated (5). The relative potency of all compounds was determined in a 72 h growth-inhibition assay against a panel of three prostate cancer cell lines (DU-145, PC-3, and LNCaP) and a human hepatoma cell line (Huh7.5.1) and compared to natural silybin B. Compounds also were evaluated for inhibition of both cytochrome P450 2C9 (CYP2C9) activity in human liver microsomes and hepatitis C virus infection in Huh7.5.1 cells. The monomethyl and dimethyl analogues were shown to have enhanced activity in terms of cytotoxicity, CYP2C9 inhibitory potency, and antiviral activity (up to 6-fold increased potency) compared to the parent compound, silybin B. In total, these data suggested that methylation of flavonolignans can increase bioactivity. Graphical Abstract
Identification of a New Spinel-Rich Lunar Rock Type by the Moon Mineralogy Mapper (M (sup 3))
The canonical characterization of the lunar crust is based principally on available Apollo, Luna, and meteorite samples. The crust is described as an anorthosite-rich cumulate produced by the lunar magma ocean that has been infused with a mix of Mgsuite components. These have been mixed and redistributed during the late heavy bombardment and basin forming events. We report a new rock-type detected on the farside of the Moon by the Moon Mineralogy Mapper (M3) on Chandrayaan-1 that does not easily fit with current crustal evolution models. The rock-type is dominated by Mg-spinel with no detectible pyroxene or olivine present (<5%). It occurs along the western inner ring of Moscoviense Basin as one of several discrete areas that exhibit unusual compositions relative to their surroundings but without morphological evidence for separate processes leading to exposure
Character and spatial distribution of OH/H<SUB>2</SUB>O on the surface of the moon seen by M<SUP>3</SUP> on Chandrayaan-1
The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration
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