Post-transcriptional regulation of the steady-state levels of mitochondrial tRNAs in HeLa cells

In human mitochondrial DNA (mtDNA), the tRNA genes are located in three different transcription units that are transcribed at three different rates. To analyze the regulation of tRNA formation by the three transcription units, we have examined the steady-state levels and metabolic properties of the tRNAs of HeLa cell mitochondria. DNA excess hybridization experiments utilizing separated strands of mtDNA and purified tRNA samples from exponential cells long term labeled with [32P]orthophosphate have revealed a steady-state level of 6 x 10(5) tRNA molecules/cell, with three-fourths being encoded in the H-strand and one-fourth in the L-strand. Hybridization of the tRNAs with a panel of M13 clones of human mtDNA containing, in most cases, single tRNA genes and a quantitation of two-dimensional electrophoretic fractionations of the tRNAs have shown that the steady-state levels of tRNA(Phe) and tRNA(Val) are two to three times higher than the average level of the other H-strand-encoded tRNAs and three to four times higher than the average level of the L-strand-encoded tRNAs. Similar experiments carried out with tRNAs isolated from cells labeled with very short pulses of [5-3H]uridine have indicated that the rates of formation of the individual tRNA species are proportional to their steady-state amounts. Therefore, the approximately 25-fold higher rate of transcription of the tRNA(Phe) and tRNA(Val) genes relative to the other H-strand tRNA genes and the 10-16-fold higher rate of transcription of the L-strand tRNA genes relative to the H-strand tRNA genes are not reflected in the steady-state levels or the rates of formation of the corresponding tRNAs. A comparison of the steady-state levels of the individual tRNAs with the corresponding codon usage for protein synthesis, as determined from the DNA sequence and the rates of synthesis of the various polypeptides, has not revealed any significant correlation between the two parameters

Analysis for Hybrid Rocket Fuel Regression Using Stereolithographic Geometry

Hybrid Rocket Engines (HRE) have characteristically low fuel regression that limits their performance. Additive manufacturing and rapid prototyping can possibly solve some of the problems with Hybrid propulsion regression by creating geometry not possible with conventional manufacturing. This work is attempting to make geometric regression simulation of HRE easier by using STereoLithography (STL files) as the geometry. This analysis sets flow conditions, boundary conditions, propellant selection, and allows for fuel geometry to be altered to simulate geometry’s effects on regression rate and propellant performance. This model can be used for more advanced geometric analysis to improve and predict performance

Revisiting the 20th century: tales of wonder and desperation

A collection of short fiction by Michael Pearson King

Military service and crime: new evidence

BACKGROUND: Evidence indicates that a substantial proportion of military personnel are involved in high-risk and antisocial behaviors that place them at jeopardy for criminal justice system involvement. However, prior research on military service and crime has disproportionately focused on veterans from the Vietnam War era (1955–1975), and has tended to focus on either current or former military members. METHODS: This study employed data from a population-based study (i.e., National Study on Drug Use and Health [NSDUH] between 2002 and 2014). It systematically examines the prevalence of self-reported antisocial behaviors, criminal justice system involvement, and substance abuse among the US civilian population and military service members, including reservists (n = 2206) and those who reported having been separated or retired from military service (n = 20,551). These factors are further examined across the developmental spectrum of adulthood (ages 18–34, 35–49, and 50–64). RESULTS: Results showed that military members were more prone to lifetime arrests and overall substance misuse. However, additional findings emerged suggesting that, while the military population overall seems to be positively associated with higher criminal activity than that found in the civilian population, these findings were based on a specific subgroup of the veteran population. This subgroup is comprised of individuals who likely did not fit in with the military culture and were discharged from the military early in their careers. CONCLUSION: Additional research on identifying this subgroup of military members is encouraged to better concentrate on prevention and treatment measures

A combined NMR and DFT study of Narrow Gap Semiconductors: The case of PbTe

In this study we present an alternative approach to separating contributions to the NMR shift originating from the Knight shift and chemical shielding by a combination of experimental solid-state NMR results and ab initio calculations. The chemical and Knight shifts are normally distinguished through detailed studies of the resonance frequency as function of temperature and carrier concentration, followed by extrapolation of the shift to zero carrier concentration. This approach is time-consuming and requires studies of multiple samples. Here, we analyzed $^{207}$Pb and $^{125}$Te NMR spin-lattice relaxation rates and NMR shifts for bulk and nanoscale PbTe. The shifts are compared with calculations of the $^{207}$Pb and $^{125}$Te chemical shift resonances to determine the chemical shift at zero charge carrier concentration. The results are in good agreement with literature values from carrier concentration-dependent studies. The measurements are also compared to literature reports of the $^{207}$Pb and $^{125}$Te Knight shifts of $n$- and $p$-type PbTe semiconductors. The literature data have been converted to the currently accepted shift scale. We also provide possible evidence for the "self-cleaning effect" property of PbTe nanocrystals whereby defects are removed from the core of the particles, while preserving the crystal structure.Comment: 34 pages, 9 figure

Panel. Other Faulkners

Nothing Has Been Resolved: Mimesis and the Modern Dance Interpretations of As I Lay Dying / Michael P. Bibler, Manchester UniversityThis presentation introduces and discusses two important dramatic interpretations of Faulkner’s As I Lay Dying: Jean-Louis Barrault’s avant-garde French production Autour d’une Mère (1935) and Valerie Bettis’s U.S. modern dance production As I Lay Dying (1949). Given the obvious emphasis on bodily expression, these interpretations raise interesting questions about the novel’s use of language and the difficulty (even impossibility) of mimetic representation. Yet my purpose here is not just to show how these dances help illustrate or illuminate Faulkner’s work. Rather, I’m more interested in exploring how these three works help decenter Faulkner’s place in the modernist canon by placing greater attention on questions of performance, intertextuality, and collaboration—questions already raised by the multi-vocal form of the novel itself. Toward a Camp Appreciation of Faulkner’s Sanctuary / Ben Robbins, Freie Universität BerlinI would like to argue that both Faulkner’s novel Sanctuary (1932) and the film treatments he made of the novel for MGM in the early 1930s can be read with a camp sensibility, since they possess many aesthetic hallmarks of camp, including heightened stylization, theatricality, amorality, exaggeration, failed seriousness, and a predilection towards artifice. I am particularly interested in exploring those moments where the novel particularly, to quote Susan Sontag in her landmark essay from 1964, ‘Notes on Camp’, “proposes itself seriously, but cannot be taken seriously because it is ‘too much.’” I will show how a camp reading of Sanctuary can help us understand how the novel disturbs the high/low axes by which we judge the Faulknerian canon. William Faulkner and a Family Who Influenced Him / Sally Wolff-King, Emory UniversityWilliam Faulkner’s celebrated heroine of The Sound and the Fury, Caddy Compson, may have had a real-life antecedent. That is a theory mentioned in Ledgers of History: William Faulkner, an Almost Forgotten Friendship, and an Antebellum Plantation Diary. More evidence to support that argument has come to light since the publication of Ledgers of History, however, and research indicates that a cousin of the McCarroll/Francisco/Leak family could be that person. The McCarroll/Francisco/Leak family of Holly Springs and Salem, Mississippi, came into focus recently when it became clear that they inherited and preserved a nineteenth-century plantation diary, in their possession for several generations. What Faulkner discovered in the diary of long ago informed his fiction in myriad ways, including plot, characterization, theme, and detail. Leak/McCarroll/Francisco family stories, however, also seem to have found their way into plotlines of The Sound and the Fury, Absalom, Absalom! and The Unvanquished. That Faulkner drew from the real life around him has been well known since his lifetime, but the case seems stronger than ever that members of this particular family, whom he knew well and visited often, may have been—in ways not previously recognized—sources for some of Faulkner’s most famous novels

The Fundamental Plane of Black Hole Accretion and its Use as a Black Hole-Mass Estimator

We present an analysis of the fundamental plane of black hole accretion, an empirical correlation of the mass of a black hole ($M$), its 5 GHz radio continuum luminosity ($\nu L_{\nu}$), and its 2-10 keV X-ray power-law continuum luminosity ($L_X$). We compile a sample of black holes with primary, direct black hole-mass measurements that also have sensitive, high-spatial-resolution radio and X-ray data. Taking into account a number of systematic sources of uncertainty and their correlations with the measurements, we use Markov chain Monte Carlo methods to fit a mass-predictor function of the form $\log(M/10^{8}\,M_{\scriptscriptstyle \odot}) = \mu_0 + \xi_{\mu R} \log(L_R / 10^{38}\,\mathrm{erg\,s^{-1}}) + \xi_{\mu X} \log(L_X / 10^{40}\,\mathrm{erg\,s^{-1}})$. Our best-fit results are $\mu_0 = 0.55 \pm 0.22$, $\xi_{\mu R} = 1.09 \pm 0.10$, and $\xi_{\mu X} = -0.59^{+0.16}_{-0.15}$ with the natural logarithm of the Gaussian intrinsic scatter in the log-mass direction $\ln\epsilon_\mu = -0.04^{+0.14}_{-0.13}$. This result is a significant improvement over our earlier mass scaling result because of the increase in active galactic nuclei sample size (from 18 to 30), improvement in our X-ray binary sample selection, better identification of Seyferts, and improvements in our analysis that takes into account systematic uncertainties and correlated uncertainties. Because of these significant improvements, we are able to consider potential influences on our sample by including all sources with compact radio and X-ray emission but ultimately conclude that the fundamental plane can empirically describe all such sources. We end with advice for how to use this as a tool for estimating black hole masses.Comment: ApJ Accepted. Online interactive version of Figure 7 available at http://kayhan.astro.lsa.umich.edu/supplementary_material/fp