Syntheses of (+)-30-epi-, (-)-6-epi-, (±)-6,30-epi-13,14-didehydroxyisogarcinol and (±)-6,30-epi-garcimultiflorone A utilizing highly diastereoselective, Lewis acid-controlled cyclizations

The first syntheses of 13,14-didehydroxyisogarcinol (6) and garcimultiflorone A (5) stereoisomers are reported in six steps from a commercially available phloroglucinol. Lewis acid-controlled, diastereoselective cationic oxycyclizations enabled asymmetric syntheses of (-)-6-epi-6 and (+)-30-epi-6. A similar strategy enabled production of the meso-dervied isomers (±)-6,30-epi-6 and (±)-6,30-epi-5. Finally, a convenient strategy for gram scale synthesis was developed utilizing diastereomer separation at a later stage in the synthesis that minimized the number of necessary synthetic operations to access all possible stereoisomers.R01 GM073855 - NIGMS NIH HHS; R24 GM111625 - NIGMS NIH HHS; R35 GM118173 - NIGMS NIH HH

Indicators of hot fluid migration in sedimentary basins: evidence from the UK Atlantic Margin

Microthermometric, petrographic and isotopic methods have been used to detect evidence for hot fluid flow in Mesozoic and Tertiary sediments from the NW UK continental margin, West of Shetland. New data presented here show that temperatures are hotter by c. 40°C in Tertiary samples than in the underlying Jurassic and Cretaceous sediments in wells 204/28-1, 206/5-2, 208/27-1, especially in cements from samples as young as mid–upper Eocene in age. Paleocene samples can be discriminated from older (Jurassic and Cretaceous) and younger (Eocene) sandstones on the basis of silica cement morphology and cathodoluminescence zonation. Jurassic, Cretaceous and Eocene quartz cements show oscillatory zoning as a consequence of relatively slow burial cementation. In direct contrast, rapid precipitation of silica cements from the cooling of hot fluids has produced unzoned cements in all but one Paleocene sample. No evidence for unzoned quartz cements was noted in any pre-Paleocene or Eocene samples. The restriction of hot fluid inclusions and unzoned cements to the Paleocene and post-Paleocene is consistent with lateral focusing of hot fluids. Isotopic data from kaolinites indicate that these fluids are best represented by mixtures of Mesozoic or Tertiary meteoric waters and marine porewaters that have undergone isotopic alteration through interaction with volcanic material. Our results indicate that hot fluid flow occurred over a relatively long time-scale (i.e. several million years), which may have important consequences for the degradation of reservoired hydrocarbons in West of Shetland Paleocene plays

Application of Finite Element to Evaluate Material with Small Modulus of Elasticity

This thesis describes the development of a series of models utilizing the commercial finite element suite ABAQUS specifically to apply towards the study of biological tissue. The end goal is to be able to obtain the material properties of the Manducca Sexta, a biological inspiration for flapping wing micro-air vehicles. Two finite element models were used to analyze the results of two prior studies of other researchers. A flat punch elastic model examined boundary effects and confirmed that the point of indentation was far enough removed from the boundary. The hyperelastic spherical indentation experiment examined the effects of coefficient of friction on the indentation. Another algorithm was reproduced to analyze the elastic, power law-hardening properties of a wide range of material properties. A nanoindentation system was used to investigate the modulus of the M. Sexta. Due to instrument limitations, useful data was not able to be collected. An upper bound on the modulus was established on the order of 1 MPa. A uniaxial tension test of the M.Sexta was used to obtain a reported initial modulus of elasticity values of 343 kPa

Creepy (not KREEPy) Gold-Indium Intermetallic Compounds on Secondary Ion Mass Spectrometry Samples

A series of Secondary Ion Mass Spectrometry (SIMS) sessions to measure hydrogen (H) in Martian meteorite minerals was completed using the Cameca 6f SIMS and NanoSIMS 50L at Arizona State University (ASU). During these sessions, a creeping phenomenon has occurred, where the edges of samples pressed in indium are covered by a metal alloy. We summarize these observations herein, present a collection of preliminary data, and discuss explanations and concerns for future SIMS work. We conclude the report with a research plan for further study

Numerical investigation of turbulence effects on boundary layer separation in axisymmetric scramjet inlets via design optimisation

Inlet aerodynamics plays a key role in the successful operation of hypersonic airbreathing systems for flexible and economical access-to-space and atmospheric flight. Flow separation, however, can critically deteriorate the engine performance particularly for internal-compression scramjets with high contraction, where the boundary layer is susceptible to adverse pressure gradients. The flow physics of an axisymmetric scramjet inlet is investigated by means of the design optimisation of transition trip wires

Regiodivergent photocyclization of dearomatized acylphloroglucinols: asymmetric syntheses of (—)-nemorosone and (—)-6-epi-garcimultiflorone A

Regiodivergent photocyclization of dearomatized acylphloroglucinol substrates has been developed to produce type A polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives using an excited-state intramolecular proton transfer (ESIPT) process. Using this strategy, we achieved the enantioselective total syntheses of the type A PPAPs (—)-nemorosone and (—)-6-epi-garcimultiflorone A. Diverse photocyclization substrates have been investigated leading to divergent photocyclization processes as a function of tether length. Photophysical studies were performed, and photocyclization mechanisms were proposed based on investigation of various substrates as well as deuterium-labeling experiments.R35 GM118173 - NIGMS NIH HHSAccepted manuscriptSupporting documentatio

An Upper Limit on the Mass of a Central Black Hole in the Large Magellanic Cloud from the Stellar Rotation Field

We constrain the possible presence of a central black hole (BH) in the center of the Large Magellanic Cloud (LMC). This requires spectroscopic measurements over an area of order a square degree, due to the poorly known position of the kinematic center. Such measurements are now possible with the impressive field of view of the Multi Unit Spectroscopic Explorer (MUSE) on the ESO Very Large Telescope. We used the Calcium Triplet (~850nm) spectral lines in many short-exposure MUSE pointings to create a two-dimensional integrated-light line-of-sight velocity map from the ~$10^8$ individual spectra, taking care to identify and remove Galactic foreground populations. The data reveal a clear velocity gradient at an unprecedented spatial resolution of 1 arcmin$^{2}$. We fit kinematic models to arrive at a $3\sigma$ upper-mass-limit of $10^{7.1}$ M$_{Sun}$ for any central BH - consistent with the known scaling relations for supermassive black holes and their host systems. This adds to the growing body of knowledge on the presence of BHs in low-mass and dwarf galaxies, and their scaling relations with host-galaxy properties, which can shed light on theories of BH growth and host system interaction.Comment: 12 pages, 11 figures, 1 table, ApJ - in pres

The New Environmental Activists: Fighting Pollution, Poverty and Racism by Building Natural Assets

In the spring of 2001, a diverse group of Americans gathered in Baton Rouge, Louisiana for a three-day environmental conference. These men and women, mostly from low-income neighborhoods and communities of color, traveled from urban housing projects and suburban neighborhoods -- from the bayous of Louisiana, the coalfields of West Virginia, and the deserts of Southern California. They came from abandoned mining towns in Idaho, agrarian regions of the South, and traditional Native American villages in New Mexico. Sadly, many of these Americans were coming to Baton Rouge as witnesses to report stories of corrupt governmental officials trading their communities' rights to clean air, water, and land for corporate payoffs and political favors. The Baton Rouge conference was organized for two reasons. One was to unite these heroines and heroes of modern America -- those who are working to free future generations from the environmental degradation that has cast shadows on their lives. The other was to introduce a new tool into their strategic plans for restoration and prevention -- a concept that could help them reclaim their democratic right to a clean environment and enable them to build economically sustainable and environmentally friendly community infrastructures. This new tool is the natural assets movement, a radical notion that seeks to simultaneously reduce poverty and protect the environment. This new movement is predicated on the notion that poor communities and communities of color have wrongly been blamed for the environmental degradation plaguing their urban or rural settings. Rather than viewing the environment through a human vs. nature lens, natural-asset-buiding strategies regard the problem as human vs. human, and in many cases, as wealthy humans vs. poor humans. Since the rise of industrialization, government officials and corporations have often viewed economically poor communities and communities of color as politically and economically weak and therefore easy prey. For three decades, the environmental justice movement has argued that the disproportionate siting of hazards in communities of color and poor neighborhoods reflects a cold-hearted calculation based on the unlikelihood of effective resistance by residents. Through the lens of natural-assets-building, the potential strength of resistance a community can offer may be measured by the level of assets, or capital, it can use in its defense. Communities with less economic or political power are learning how to strengthen their "social capital" -- their bonds with each other and bridges to others -- by organizing effective strategies in large numbers