3,498 research outputs found
Dry Reforming of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts
This research focuses on the synthesis of both shaped and amorphous powder materials, the combination of these materials with dried Powder River Basin (PRB) coal char, and their reactionary properties with methane and carbon dioxide gasses with conventional and microwave (MW) heating. The first goal of this project was to synthesize shaped micro and nano sized particles with ideal dielectric properties for converting electromagnetic energy into heat and proven capabilities of activating methane. These particles were synthesized via solvothermal, hydrothermal, and co-preceptory treatments alone and onto the surface of dried PRB coal char. PRB is a sub-bituminous, low-ranking coal (LRC) containing impurities processing ideal properties for heating using microwave radiation. MW irradiation of metal oxides and char improved conversion of reforming gasses (CH4 and CO2), reacting at lower temperatures than typically used with conventional heating methods. Lower DRM temperature parameters translate into diminished energy requirements, optimizing cost minimalization for a manufacturer. Outlet stream gases were monitored to examine effects of altering a particle’s morphology, size, and shape, and the products that evolve from these reactor experiments. Additionally, varying the wt% of the catalysts on the dried PRB coal char were tested. Characterizations were completed using scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature-controlled desorption (TPD), thermogravimetric analysis (TGA), gas chromatography (GC), and transmission line and free space method dielectric testing on all the materials synthesized. The purpose of this research was to improve understandings and the development of low-rank coal char to fuel synthesis, evaluate solid/gas interactions between Mo-based metal oxides, PRB coal char, and reforming gases, analyze the effects of MW irradiation use in these reactions compared to conventional heating methods, observe the effects of metal oxide particle sizes/morphologies and their effects on reforming reactions, and increase future viability and applicability of these processes
An analysis of human Alu element lineages
The Alu Ya and Yb-lineages are distinct groups of Short INterspersed Elements (SINEs) found exclusively in primates. These lineages are comprised of several distinct subfamilies, which contain elements that are evolutionarily-related because they share common diagnostic mutations. Some of these Alu subfamilies are still actively mobilizing in the human genome. We have recovered 4333 Ya and Yb-lineage elements that reside in the human genome draft sequence and focused our analyses on the 4051 autosomal Alu elements. A total of 2672 autosomal loci were subjected to polymerase chain reaction (PCR)-based assays that allow analysis of individual elements for insertion presence and absence. The polymorphism rate for the insertion presence/absence on the human autosomes was 22% and 20% for the Ya and Yb-lineages, respectively. Less than 0.5% (12/2672) of the loci analyzed by PCR displayed positive results for insertions in the orthologous loci of various non-human primate genomes. DNA sequence analysis of these inserts showed that the non-human primate orthologous loci contained older, pre-existing Y, Sc, Sg, Sq or Sx Alu subfamily elements. These PCR results were the result of various evolutionary processes within the human lineage. This is the largest analysis of human Alu mobile element lineages to date. The size, evolutionary age and variable allele insertion frequencies of the Alu Ya and Yb-lineage subfamilies, makes these elements useful tools for human population genetics, human identification and primate comparative genomics
President Bill Clinton, African Americans, And The Politics Of Race And Class
In 2001, President Bill Clinton left the White House as one of the most popular and controversial presidents in modern American history. A booming economy, strong dollar, and relative peace in the United States signaled a golden era; an era sandwiched between the end of the Cold War and the beginning of the War on Terror. In addition, much of the racial animus and vitriol of the 1970s and 1980s had seemingly subsided. Yet, underneath that veneer of a placid and complacent country enjoying the fruits of its labor in the post Cold War era was a nation experiencing the pangs of divisions between black and white, poor and affluent, Republican and Democrat. These divisions, as they concerned race, led to the belief that President Clinton was the first black president. A supposed woman-loving junk food eating, saxophone playing, honorary brother, Clinton became almost unrecognizable from the caricature of him. He loved black people. He hired black people. He hung out with black people. Clinton was the defendeer of African Americans against the reactionaries of the Republican Party. That image was at odds with the reality of his presidency. In fact, Clinton signaled as early as 1991 that he was not an old Democrat, but a New Democrat. Market-based solutions to complex problems, racial moderation, and conciliatory approaches to politics defined the Clinton era. This dissertation examines Clinton and the real impact he had on his most loyal supporters, African Americans. It considers several major events during the 1990s to examine the politics of race and class, including the Lani Guinier nomination, the rise of the Democratic Leadership Council, the battles over welfare reform and crime legislation, and the race initiative. These case studies provide a lens through which we can understand the racial impact of one of the most important administrations in recent memory
The Life and Public Career of Robert F. Kennedy.
There have been many notable politicians in the United States during the twentieth century. Some, like Teddy Roosevelt and Ronald Reagan, were known for their swagger and appeal to the common man. Others, like Bill Clinton and Franklin Roosevelt, were known for their charisma and intelligence. However, one in particular was known for caring, compassion, strength, and determination. Robert Francis Kennedy lived in interesting times, surrounded by large egos and near mythical figures. But Kennedy was arguably one of the most important figures of the last fifty years. The ideas and ideals that he espoused still resonate nearly forty years after his tragic demise. What made Robert Kennedy so unique was the circumstances of the last four and half years of his life (November 1963-June 1968). The RFK we remember today was not exactly what he really was during life. In addition, he went through a transformation unparalleled by many of his generation. This thesis tracks the life of this very important figure and shows how the assassination of his brother, John F. Kennedy, forever changed him into a titanic figure in American history
Identification and functional characterisation of a class on non-selective cation channels in Saccharomyces cerevisiae.
Na⁺ accumulation is a significant component in salt toxicity in plants. Although many proteins that facilitate Na⁺ flux have been identified in plants, investigations aimed at identifying the initial mechanism of Na⁺ entry into plants have failed. The catalysis of rapid, high capacity flux of Na⁺ across plant cell membranes, currently through unknown means, is of particular importance. Observations of Na⁺ flux across cellular membranes, using techniques such as electrophysiology and radiotracer flux, suggests this is a protein-based catalysis (Demidchik, 2002a; Demidchik and Tester, 2002c) (Essah et al., 2003). Based on these data, a class of protein described as voltage insensitive non-selective cation channel(s) (viNSCCs) are considered a good candidate for this Na⁺ flux. This is due in part to characteristics they possess. These characteristics include catalysis of high capacity / low affinity cation flux, being relatively non-selective to the point where Na⁺, K⁺, NH₄⁺ and MA⁺ flux with similar properties and this flux being sensitive to elevated Ca²⁺ and changes in pH.
A screen using the toxic ammonium analogue methylammonium (MA⁺) was developed using Saccharomyces cerevisiae strains that have minimal high affinity ammonium uptake capability. An in silico screen was developed and a number of candidate genes were identified as being possible viNSCCs. Preliminary selection of these was then conducted using the developed S. cerevisiae screen. Two genes, belonging to the same protein family, were selected based upon these results.
Analysis of these proteins using radiotracer flux in S. cerevisiae and electrophysiological examination using Xenopus laevis oocytes revealed these proteins catalyse the non-selective flux of mono-valent cations following unsaturable kinetics, indicative of a low affinity transport system. Further analysis revealed this cation flux is sensitive to external Ca²⁺. These properties strongly indicate these proteins form voltage insensitive non-selective cation channels in their native system.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 200
Factors influencing the outcome of ligating the uterine artery and vein in a guinea pig model of intrauterine growth retardation
ln a retrospeetive study the outcome of uterine artery or uterine arteiy and vein ligation in 235 pregnant guinea pigs was reported. The aim of the study was to reduce the number ofanimals used in studies of IUGR, by identifying factors influencing the outcome of uterine artery ligation that could easily be changed. Differences1n outcome by ligation technique, day of ligation and maternal weight on day of ligation were analyzed Ligating only the artery gave better resultsin bilateral pregnaneies and animals with bilateral pregnancies had IUGR fetuses more often than unilaterall
Comparative aspects of trophoblast development and placentation
Based on the number of tissues separating maternal from fetal blood, placentas are classified as epitheliochorial, endotheliochorial or hemochorial. We review the occurrence of these placental types in the various orders of eutherian mammals within the framework of the four superorders identified by the techniques of molecular phylogenetics. The superorder Afrotheria diversified in ancient Africa and its living representatives include elephants, sea cows, hyraxes, aardvark, elephant shrews and tenrecs. Xenarthra, comprising armadillos, anteaters and sloths, diversified in South America. All placentas examined from members of these two oldest superorders are either endotheliochorial or hemochorial. The superorder Euarchontoglires includes two sister groups, Glires and Euarchonta. The former comprises rodents and lagomorphs, which typically have hemochorial placentas. The most primitive members of Euarchonta, the tree shrews, have endotheliochorial placentation. Flying lemurs and all higher primates have hemochorial placentas. However, the lemurs and lorises are exceptional among primates in having epitheliochorial placentation. Laurasiatheria, the last superorder to arise, includes several orders with epitheliochorial placentation. These comprise whales, camels, pigs, ruminants, horses and pangolins. In contrast, nearly all carnivores have endotheliochorial placentation, whilst bats have endotheliochorial or hemochorial placentas. Also included in Laurasiatheria are a number of insectivores that have many conserved morphological characters; none of these has epitheliochorial placentation. Consideration of placental type in relation to the findings of molecular phylogenetics suggests that the likely path of evolution in Afrotheria was from endotheliochorial to hemochorial placentation. This is also a likely scenario for Xenarthra and the bats. We argue that a definitive epitheliochorial placenta is a secondary specialization and that it evolved twice, once in the Laurasiatheria and once in the lemurs and lorises
Acid-base status and cardiovascular function in pigs anaesthetized with α-chloralose
Respiratory and cardiovascular parameters were examined in 47 pigs anaesthetized with α-chloralose 0.25% (100 mg/kg i.v.). Animals maintained under spontaneous respiration had a stable but subnormal arterial blood pressure. Heart rate was within the normal range. Respiration was depressed, causing elevated pCO2 and respiratory acidosis.Artificial ventilation with a minute volume of 0.15 1 per kg body weight normalized both cardiovascular and respiratory parameters.In conclusion α-chloralose can be considered valuable for maintaining anaesthesia in pigs during acute, non-survival experiments demanding minimal cardiovascular and pulmonary disturbance, but only where artificial ventilation is used
EXONEST: The Bayesian Exoplanetary Explorer
The fields of astronomy and astrophysics are currently engaged in an
unprecedented era of discovery as recent missions have revealed thousands of
exoplanets orbiting other stars. While the Kepler Space Telescope mission has
enabled most of these exoplanets to be detected by identifying transiting
events, exoplanets often exhibit additional photometric effects that can be
used to improve the characterization of exoplanets. The EXONEST Exoplanetary
Explorer is a Bayesian exoplanet inference engine based on nested sampling and
originally designed to analyze archived Kepler Space Telescope and CoRoT
(Convection Rotation et Transits plan\'etaires) exoplanet mission data. We
discuss the EXONEST software package and describe how it accommodates
plug-and-play models of exoplanet-associated photometric effects for the
purpose of exoplanet detection, characterization and scientific hypothesis
testing. The current suite of models allows for both circular and eccentric
orbits in conjunction with photometric effects, such as the primary transit and
secondary eclipse, reflected light, thermal emissions, ellipsoidal variations,
Doppler beaming and superrotation. We discuss our new efforts to expand the
capabilities of the software to include more subtle photometric effects
involving reflected and refracted light. We discuss the EXONEST inference
engine design and introduce our plans to port the current MATLAB-based EXONEST
software package over to the next generation Exoplanetary Explorer, which will
be a Python-based open source project with the capability to employ third-party
plug-and-play models of exoplanet-related photometric effects.Comment: 30 pages, 8 figures, 5 tables. Presented at the 37th International
Workshop on Bayesian Inference and Maximum Entropy Methods in Science and
Engineering (MaxEnt 2017) in Jarinu/SP Brasi
Evaluating the optimal definition of abnormal first-trimester uterine artery Doppler parameters to predict adverse pregnancy outcomes
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