Base-caged Adenosine Triphosphate as a Model System for Photoactivatable Small Interfering RNA

Photocaged adenosine triphosphate (ATP) is one of the earliest examples of exerting spatial-temporal control over the activity of a substrate. The activity of ATP is blocked until near-ultraviolet light exposure photocleaves the cage moiety. Caged ATP has been used for a myriad of applications including kinetic studies of ATP-dependent enzymes. Traditional caging of ATP occurs at the gamma-phosphate, which has been found to competitively inhibit several enzymatic systems. It was hypothesized that blocking access to the adenosine N6 position via cage molecule would prevent the initial enzyme-substrate binding event from occurring prior to photolysis, effectively minimizing competitive inhibition. Utilizing a convertible nucleoside analog of ATP, this work synthesized, purified, and characterized a form of caged ATP which, by attaching the cage molecule to the nucleobase, did not inhibit the enzymatic activity of luciferase in vitro. Characterization was accomplished via UV/Vis spectroscopy, high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and mass spectrometry (MS). Base-caged ATP was evaluated in a firefly luciferase enzymatic assay to determine the degree of bioactivity in the caged and photoactivated states and compared to the results of native (uncaged) ATP and gamma-NPE-caged ATP. Photolysis was conducted via 308 nm light from a transilluminator. Base-caged ATP did not inhibit the enzymatic system and the convertible nucleoside synthesis approach offers significant advantages over other caging techniques

Imperial Zions: Mormons, Polygamy, and the Politics of Domesticity in the Nineteenth Century.

This dissertation addresses how discussions of Mormon domesticity intersected with the imperial and racial politics of the nineteenth century. Analyzing missionary correspondence, official LDS church records, church publications, and personal diaries, it tracks Mormon missionaries as they move through imperial spaces such as Great Britain, the United States, and the South Pacific. In identifying Great Britain and the United States as missionary spaces, it argues, Mormons challenged the expectation that the white, middle classes would be the bearers rather than the recipients of missionary work. This was not the only way in which Mormons challenged nineteenth-century conceptions of race. This dissertation argues that in willingly entering polygamy, Mormons advocated for a form of marriage many people believed was more suited to people of color. As a result, Mormon women and their husbands were frequently racialized and portrayed as existing somewhere between white and non-white. In turn, Mormons did not reject racialized or imperial thinking in their defenses of polygamy. Rather, this dissertation concludes that they drew upon civilizing discourses, arguing that polygamy provided a better system for domesticating sexuality than monogamy because it gave men multiple outlets for their sexuality. Finally, this dissertation connects abstract discussions about sexuality and imperialism to individual lives. It explores the tensions that Mormon missionary work created both for white women whose husbands temporarily abandoned them for evangelizing missions and for indigenous women who married white Mormon men as plural wives. In connecting Mormon missionary work and domesticity, this dissertation makes an argument for the imperial nature of nineteenth-century Mormonism. Although Mormonism has been imagined and synthesized as an American faith, it has a long history of missionary work and participation in American colonialism. By exploring this idea, the dissertation illustrates how historical conceptions of Mormonism should be fully integrated into the larger history of the United States and the world.PHDHistoryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113526/1/hendrixa_1.pd

The Ultraviolet Albedo of Ganymede

A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede's stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede's UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values

Energy Options for Future Humans on Titan

We review the possibilities for in situ energy resources on Titan for use by future humans, including chemical, nuclear, wind, solar, geothermal and hydropower. All of these options, with the possible exception of geothermal, represent effective sources of power. Combustion of methane (after electrolysis of the native water), in combination with another source of power such as nuclear, is a viable option; another chemical source of energy is the hydrogenation of acetylene. The large seas Kraken and Ligeia potentially represent effective sources of hydropower. Wind power, particularly at altitudes ~40 km, is expected to be productive. Despite the distance from the sun and the absorbing atmosphere, solar power is (as on Earth) an extremely efficient source of power on Titan

Rough Surfaces: Is the Dark Stuff Just Shadow?: "Who knows what evil lurks in the hearts of men? The shadow knows!"

Remote observations of the surfaces of airless planetary objects are fundamental to inferring the physical structure and compositional makeup of the surface material. A number of forward models have been developed to reproduce the photometric behavior of these surfaces, based on specific, assumed structural properties such as macroscopic roughness and associated shadowing. Most work of this type is applied to geometric albedos, which are affected by complicated effects near zero phase angle that represent only a tiny fraction of the net energy reflected by the object. Other applications include parameter fits to resolved portions of some planetary surface as viewed over a range of geometries. The spherical albedo of the entire object (when it can be determined) captures the net energy balance of the particle more robustly than the geometric albedo. In most treatments involving spherical albedos, spherical albedos and particle phase functions are often treated as if they are independent, neglecting the effects of roughness. In this paper we take a different approach. We note that whatever function captures the phase angle dependence of the brightness of a realistic rough, shadowed, flat surface element relative to that of a smooth granular surface of the same material, it is manifested directly in both the integral phase function and the spherical albedo of the object. We suggest that, where broad phase angle coverage is possible, spherical albedos may be easily corrected for the effects of shadowing using observed (or assumed) phase functions, and then modeled more robustly using smooth-surface regolith radiative transfer models without further imposed (forward-modeled) shadowing corrections. Our approach attributes observed "power law" phase functions of various slope (and "linear" ranges of magnitude-vs.-phase angle) to shadowing, as have others, and goes on to suggest that regolith-model-based inferences of composition based on shadow-uncorrected spherical albedos overestimate the amount of absorbing material contained in the regolith

ETHNOBOTANICAL STUDY OF BERANGAN (Castanopsis spp.) IN NAGAN RAYA DISTRICT INDONESIA

Castanopsis spp., also known as berangan in Acehnese, is a chestnut species that is still used and well-known by the people of Indonesia. However, it is currently very rare and is becoming less well-known to today's younger generation. This research aims to study and understand how people in Nagan Raya process and use Castanopsis spp. species. Data were collected using two methods: ethnobotanical data and population data. The participatory rural appraisal (PRA) method was used in direct interviews to collect ethnobotanical data. Purposive sampling was used to obtain the Castanopsis spp. the population as much as local informants could show. There were 48 people from three groups of respondents who provided ethnobotanical data: traditional figures, farmers, and villagers who Castanopsis spp. species. The respondents in this study were divided into three groups based on their age, education, and occupation. There are 2 types of Castanopsis spp. that have been found in the Nagan Raya district, Castanopsis inermis and Castanopsis costata. They were discovered in forest areas, plantations, office/home yards, and roadside areas. Castanopsis spp fruits are commonly used as food, while the wood are usually used as carpentry/furniture wood and firewood. Kata Kunci: ethnobotany, berangan, chestnut, Castanopsis spp

Determining the Shape, Size, and Sources of the Zodiacal Dust Cloud using Polarized Ultraviolet Scattered Sunlight

The solar system's Zodiacal Cloud is visible to the unaided eye, yet the origin of its constituent dust particles is not well understood, with a wide range of proposed divisions between sources in the asteroid belt and Jupiter Family comets. The amount of dust contributed by Oort Cloud comets is uncertain. Knowledge of the Zodiacal Cloud's structure and origins would help with NASA's aim of characterizing potentially Earth-like planets around nearby stars, since the exo-Earths must be studied against the light scattered from extrasolar analogs of our cloud. As the only example where the parent bodies can be tracked, our own cloud is critical for learning how planetary system architecture governs the interplanetary dust's distribution. Our cloud has been relatively little-studied in the near-ultraviolet, a wavelength range that is important for identifying potentially-habitable planets since it contains the broad Hartley absorption band of ozone. We show through radiative transfer modeling that our cloud's shape and size at near-UV wavelengths can be measured from Earth orbit by mapping the zodiacal light's flux and linear polarization across the sky. We quantify how well the cloud's geometric and optical properties can be retrieved from a set of simulated disk observations, using a Markov chain Monte Carlo analysis. The results demonstrate that observations with sufficient precision, covering a set of fields distributed along the ecliptic and up to the poles, can be used to determine the division between asteroidal, Jupiter Family, and Oort Cloud dust components, primarily via their differing orbital inclination distributions. We find that the observations must be repeated over a time span of several months in order to disentangle the zodiacal light from the Galactic background using the Milky Way's rotation across the sky.Comment: submitted to PAS

Astro2020 Science White Paper: Triggered High-Priority Observations of Dynamic Solar System Phenomena

Unexpected dynamic phenomena have surprised solar system observers in the past and have led to important discoveries about solar system workings. Observations at the initial stages of these events provide crucial information on the physical processes at work. We advocate for long-term/permanent programs on ground-based and space-based telescopes of all sizes - including Extremely Large Telescopes (ELTs) - to conduct observations of high-priority dynamic phenomena, based on a predefined set of triggering conditions. These programs will ensure that the best initial dataset of the triggering event are taken; separate additional observing programs will be required to study the temporal evolution of these phenomena. While not a comprehensive list, the following are notional examples of phenomena that are rare, that cannot be anticipated, and that provide high-impact advances to our understandings of planetary processes. Examples include: new cryovolcanic eruptions or plumes on ocean worlds; impacts on Jupiter, Saturn, Uranus, or Neptune; extreme eruptions on Io; convective superstorms on Saturn, Uranus, or Neptune; collisions within the asteroid belt or other small-body populations; discovery of an interstellar object passing through our solar system (e.g. 'Oumuamua); and responses of planetary atmospheres to major solar flares or coronal mass ejections.Comment: Astro2020 white pape