• G-Quadruplex in the NRF2 mRNA 5′ Untranslated Region Regulates De Novo NRF2 Protein Translation under Oxidative Stress

      Lee, Sang C.; Zhang, Jack; Strom, Josh; Yang, Danzhou; Dinh, Thai Nho; Kappeler, Kyle; Chen, Qin M.; Univ Arizona, Coll Med, Dept Pharmacol (AMER SOC MICROBIOLOGY, 2017-01-01)
      Inhibition of protein synthesis serves as a general measure of cellular consequences of chemical stress. A few proteins are translated selectively and influence cell fate. How these proteins can bypass the general control of translation remains unknown. We found that low to mild doses of oxidants induce de novo translation of the NRF2 protein. Here we demonstrate the presence of a G-quadruplex structure in the 5' untranslated region (UTR) of NRF2 mRNA, as measured by circular dichroism, nuclear magnetic resonance, and dimethylsulfate footprinting analyses. Such a structure is important for 5'-UTR activity, since its removal by sequence mutation eliminated H2O2-induced activation of the NRF2 5' UTR. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics revealed elongation factor 1 alpha (EF1a) as a protein binding to the G-quadruplex sequence. Cells responded to H2O2 treatment by increasing the EF1a protein association with NRF2 mRNA, as measured by RNA-protein interaction assays. The EF1a interaction with small and large subunits of ribosomes did not appear to change due to H2O2 treatment, nor did post translational modifications, as measured by two-dimensional (2-D) Western blot analysis. Since NRF2 encodes a transcription factor essential for protection against tissue injury, our data have revealed a novel mechanism of cellular defense involving de novo NRF2 protein translation governed by the EF1a interaction with the G-quadruplex in the NRF2 5' UTR during oxidative stress.
    • GABA-A receptor modulating steroids in acute and chronic stress; relevance for cognition and dementia?

      Bengtsson, S K S; Bäckström, T; Brinton, R; Irwin, R W; Johansson, M; Sjöstedt, J; Wang, M D; Univ Arizona, Coll Med, Dept Pharmacol, Ctr Innovat Brain Sci (ELSEVIER SCIENCE INC, 2019-12-20)
      Cognitive dysfunction, dementia and Alzheimer's disease (AD) are increasing as the population worldwide ages. Therapeutics for these conditions is an unmet need. This review focuses on the role of the positive GABA-A receptor modulating steroid allopregnanolone (APa), it's role in underlying mechanisms for impaired cognition and of AD, and to determine options for therapy of AD. On one hand, APa given intermittently promotes neurogenesis, decreases AD-related pathology and improves cognition. On the other, continuous exposure of APa impairs cognition and deteriorates AD pathology. The disparity between these two outcomes led our groups to analyze the mechanisms underlying the difference. We conclude that the effects of APa depend on administration pattern and that chronic slightly increased APa exposure is harmful to cognitive function and worsens AD pathology whereas single administrations with longer intervals improve cognition and decrease AD pathology. These collaborative assessments provide insights for the therapeutic development of APa and APa antagonists for AD and provide a model for cross laboratory collaborations aimed at generating translatable data for human clinical trials.
    • Gain spectroscopy of a type-II VECSEL chip

      Lammers, C.; Stein, M.; Berger, C.; Möller, C.; Fuchs, C.; Ruiz Perez, A.; Rahimi-Iman, A.; Hader, J.; Moloney, J. V.; Stolz, W.; et al. (AMER INST PHYSICS, 2016-12-05)
      Using optical pump-white light probe spectroscopy, the gain dynamics is investigated for a vertical-external-cavity surface-emitting laser chip, which is based on a type-II heterostructure. The active region of the chip consists of a GaAs/(GaIn) As/Ga(AsSb)/(GaIn) As/GaAs multiple quantum well. For this structure, a fully microscopic theory predicts a modal room temperature gain at a wavelength of 1170 nm, which is confirmed by the experimental spectra. The results show a gain buildup on the type-II chip that is delayed relative to that of a type-I chip. This slower gain dynamics is attributed to a diminished cooling rate arising from the reduced electron-hole scattering. Published by AIP Publishing.
    • Gait changes in a line of mice artificially selected for longer limbs

      Sparrow, Leah M.; Pellatt, Emily; Yu, Sabrina S.; Raichlen, David A.; Pontzer, Herman; Rolian, Campbell; Univ Arizona, Sch Anthropol; Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada; Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; et al. (PEERJ INC, 2017-02-22)
      In legged terrestrial locomotion, the duration of stance phase, i.e., when limbs are in contact with the substrate, is positively correlated with limb length, and negatively correlated with the metabolic cost of transport. These relationships are well documented at the interspecific level, across a broad range of body sizes and travel speeds. However, such relationships are harder to evaluate within species (i.e., where natural selection operates), largely for practical reasons, including low population variance in limb length, and the presence of confounding factors such as body mass, or training. Here, we compared spatiotemporal kinematics of gait in Longshanks, a long-legged mouse line created through artificial selection, and in random-bred, mass-matched Control mice raised under identical conditions. We used a gait treadmill to test the hypothesis that Longshanks have longer stance phases and stride lengths, and decreased stride frequencies in both fore- and hind limbs, compared with Controls. Our results indicate that gait differs significantly between the two groups. Specifically, and as hypothesized, stance duration and stride length are 8–10% greater in Longshanks, while stride frequency is 8% lower than in Controls. However, there was no difference in the touch-down timing and sequence of the paws between the two lines. Taken together, these data suggest that, for a given speed, Longshanks mice take significantly fewer, longer steps to cover the same distance or running time compared to Controls, with important implications for other measures of variation among individuals in whole-organism performance, such as the metabolic cost of transport.

      Barnes, Peter J.; Hernandez, Audra K.; O’Dougherty, Stefan N.; Schap III, William J.; Muller, Erik; Univ Arizona, Coll Opt Sci (IOP PUBLISHING LTD, 2016-10-27)
      We report the second complete molecular line data release from the Census of High-and Medium-mass Protostars (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of millimeter-wave line emission from 303 massive, dense molecular clumps in the Milky Way. This release is for all (CO)-C-12 J = 1 -> 0 emission associated with the dense gas, the first from Phase II of the survey, which includes (CO)-C-12, (CO)-C-13, and (CO)-O-18. The observed clump emission traced by both (CO)-C-12 and HCO+ (from Phase I) shows very similar morphology, indicating that, for dense molecular clouds and complexes of all sizes, parsec-scale clumps contain. similar to 75% of the mass, while only 25% of the mass lies in extended (>10 pc) or "low density" components in these same areas. The mass fraction of all gas above a density of 10(9) m(-3) is xi(9) greater than or similar to 50%. This suggests that parsec-scale clumps may be the basic building blocks of the molecular interstellar medium, rather than the standard GMC concept. Using (CO)-C-12 emission, we derive physical properties of these clumps in their entirety, and compare them to properties from HCO+, tracing their denser interiors. We compare the standard X-factor converting I (CO)-C-12 to N-H2 with alternative conversions, and show that only the latter give whole-clump properties that are physically consistent with those of their interiors. We infer that the clump population is systematically closer to virial equilibrium than when considering only their interiors, with perhaps half being long-lived (10s of Myr), pressure-confined entities that only terminally engage in vigorous massive star formation, supporting other evidence along these lines that was previously published.

      Li, Linlin; Shen, Shiyin; Hou, Jinliang; Yuan, Fangting; Zhong, Jing; Zou, Hu; Zhou, Xu; Jiang, Zhaoji; Peng, Xiyan; Fan, Dongwei; et al. (IOP PUBLISHING LTD, 2017-01-30)
      We study the integral Galactic extinction and reddening based on the galaxy catalog of the South Galactic Cap u-band Sky Survey (SCUSS), where u-band galaxy number counts and u - r color distribution are used to derive the Galactic extinction and reddening respectively. We compare these independent statistical measurements with the reddening map of Schlegel et al. (SFD) and find that both the extinction and reddening from the number counts and color distribution are in good agreement with the SFD results at low extinction regions (E(B - V)(SFD) < 0.12 mag). However, for high extinction regions (E(B - V)(SFD) > 0.12 mag), the SFD map overestimates the Galactic reddening systematically, which can be approximated by a linear relation Delta E(B - V)= 0.43[ E(B - V)(SFD) - 0.12]. By combining the results from galaxy number counts and color distribution, we find that the shape of the Galactic extinction curve is in good agreement with the standard R-V = 3.1 extinction law of O'Donnell.
    • Galaxy cluster luminosities and colours, and their dependence on cluster mass and merger state

      Mulroy, Sarah L.; McGee, Sean L.; Gillman, Steven; Smith, Graham P.; Haines, Chris P.; Démoclès, Jessica; Okabe, Nobuhiro; Egami, Eiichi; Univ Arizona, Steward Observ (OXFORD UNIV PRESS, 2017-12)
      We study a sample of 19 galaxy clusters in the redshift range 0.15 < z < 0.30 with highly complete spectroscopic membership catalogues (to K < K*(z) + 1.5) from the Arizona Cluster Redshift Survey, individual weak-lensing masses and near-infrared data from the Local Cluster Substructure Survey, and optical photometry from the Sloan Digital Sky Survey. We fit the scaling relations between total cluster luminosity in each of six bandpasses (grizJK) and cluster mass, finding cluster luminosity to be a promising mass proxy with low intrinsic scatter sigma ln (L|M) of only similar to 10-20 per cent for all relations. At fixed overdensity radius, the intercept increases with wavelength, consistent with an old stellar population. The scatter and slope are consistent across all wavelengths, suggesting that cluster colour is not a function of mass. Comparing colour with indicators of the level of disturbance in the cluster, we find a narrower variety in the cluster colours of 'disturbed' clusters than of 'undisturbed' clusters. This trend is more pronounced with indicators sensitive to the initial stages of a cluster merger, e.g. the Dressler Schectman statistic. We interpret this as possible evidence that the total cluster star formation rate is 'standardized' in mergers, perhaps through a process such as a system-wide shock in the intracluster medium.
    • Galaxy Cluster Mass Estimates in the Presence of Substructure

      Tucker, Evan; Walker, Matthew G.; Mateo, Mario; Olszewski, Edward W.; Geringer-Sameth, Alex; Miller, Christopher J.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2020-01-15)
      We develop and implement a model to analyze the internal kinematics of galaxy clusters that may contain subpopulations of galaxies that do not independently trace the cluster potential. The model allows for substructures within the cluster environment and disentangles cluster members from contaminating foreground and background galaxies. We estimate the cluster velocity dispersion and/or mass while marginalizing over uncertainties in all of the above complexities. Using mock observations from the MultiDark simulation, we compare the true substructures from the simulation with the substructures identified by our model, showing that 50% of the identified substructures have at least 79% of its members are also members of the same true substructure, which is on par with other substructure identification algorithms. Furthermore, we show a similar to 35% decrease in scatter in the inferred velocity dispersion versus true cluster mass relationship when comparing a model that allows three substructures to a model that assumes no substructure. In a first application to our published data for A267, we identify up to four distinct galaxy subpopulations. We use these results to explore the sensitivity of inferred cluster properties to the treatment of substructure. Compared to a model that assumes no substructure, our substructure model reduces the dynamical mass of A267 by similar to 22% and shifts the cluster mean velocity by similar to 100 km s(-1), approximately doubling the offset with respect to the velocity of A267's brightest cluster galaxy. Embedding the spherical Jeans equation within this framework, we infer for A267 a halo mass M-200 = (7.0 1.3) x 10(14) Mh(-1) and concentration <i , consistent with the mass-concentration relation found in cosmological simulations.
    • Galaxy cluster mass estimation from stacked spectroscopic analysis

      Farahi, Arya; Evrard, August E.; Rozo, Eduardo; Rykoff, Eli S.; Wechsler, Risa H.; Univ Arizona, Dept Phys (OXFORD UNIV PRESS, 2016-08-21)
      We use simulated galaxy surveys to study: (i) how galaxy membership in redMaPPer clusters maps to the underlying halo population, and (ii) the accuracy of a mean dynamical cluster mass, M-sigma(lambda), derived from stacked pairwise spectroscopy of clusters with richness lambda. Using similar to 130 000 galaxy pairs patterned after the Sloan Digital Sky Survey (SDSS) redMaPPer cluster sample study of Rozo et al., we show that the pairwise velocity probability density function of central-satellite pairs with m(i) < 19 in the simulation matches the form seen in Rozo et al. Through joint membership matching, we deconstruct the main Gaussian velocity component into its halo contributions, finding that the top-ranked halo contributes similar to 60 per cent of the stacked signal. The halo mass scale inferred by applying the virial scaling of Evrard et al. to the velocity normalization matches, to within a few per cent, the log-mean halo mass derived through galaxy membership matching. We apply this approach, along with miscentring and galaxy velocity bias corrections, to estimate the log-mean matched halo mass at z = 0.2 of SDSS redMaPPer clusters. Employing the velocity bias constraints of Guo et al., we find aEuroln (M-200c)|lambda aEuro parts per thousand = ln (< M-30) + alpha(m) ln (lambda/30) with M-30 = 1.56 +/- 0.35 x 10(14) M-aS (TM) and alpha(m) = 1.31 +/- 0.06(stat) +/- 0.13(sys). Systematic uncertainty in the velocity bias of satellite galaxies overwhelmingly dominates the error budget.
    • Galaxy growth in a massive halo in the first billion years of cosmic history

      Marrone, Daniel P.; Spilker, J. S.; Hayward, C. C.; Vieira, J. D.; Aravena, Manuel; Ashby, M. L. N.; Bayliss, M. B.; Béthermin, M.; Brodwin, Mark; Bothwell, M. S.; et al. (NATURE PUBLISHING GROUP, 2018-01-04)
      According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field(1-3). Observing these structures during their period of active growth and assembly-the first few hundred million years of the Universe-is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far(4,5). Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey(6). High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe(7). These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.
    • Galaxy Merger Fractions in Two Clusters at z similar to 2 Using the Hubble Space Telescope

      Watson, Courtney; Tran, Kim-Vy; Tomczak, Adam; Alcorn, Leo; Salazar, Irene V.; Gupta, Anshu; Momcheva, Ivelina; Papovich, Casey; Dokkum, Pieter van; Brammer, Gabriel; et al. (IOP PUBLISHING LTD, 2019-03-25)
      We measure the fraction of galaxy-galaxy mergers in two clusters at z similar to 2 using imaging and grism observations from the Hubble Space Telescope. The two galaxy cluster candidates were originally identified as overdensities of objects using deep mid-infrared imaging and observations from the Spitzer Space Telescope, and were subsequently followed up with HST/WFC3 imaging and grism observations. We identify galaxy-galaxy merger candidates using high-resolution imaging with the WFC3 in the F105W, F125W, and F160W bands. Coarse redshifts for the same objects are obtained with grism observations in G102 for the z similar to 1.6 cluster (IRC0222A) and G141 for the z similar to 2 cluster (IRC0222B). Using visual classifications as well as a variety of selection techniques, we measure merger fractions of 11(-3.2)(+8.2) in IRC0222A and 18(-4.5)(+7.8) in IRC0222B. In comparison, we measure a merger fraction of 5.0(-0.8)(+1.1)% for field galaxies at z similar to 2. Our study indicates that the galaxy-galaxy merger fraction in clusters at z similar to 2 is enhanced compared to the field population, but note that more cluster measurements at this epoch are needed to confirm our findings.
    • Galaxy morphological classification in deep-wide surveys via unsupervised machine learning

      Martin, G; Kaviraj, S; Hocking, A; Read, S C; Geach, J E; Univ Arizona, Steward Observ (OXFORD UNIV PRESS, 2019-10-26)
      Galaxy morphology is a fundamental quantity, which is essential not only for the full spectrum of galaxy-evolution studies, but also for a plethora of science in observational cosmology (e.g. as a prior for photometric-redshift measurements and as contextual data for transient light-curve classifications). While a rich literature exists on morphological-classification techniques, the unprecedented data volumes, coupled, in some cases, with the short cadences of forthcoming 'Big-Data' surveys (e.g. from the LSST), present novel challenges for this field. Large data volumes make such data sets intractable for visual inspection (even via massively distributed platforms like Galaxy Zoo), while short cadences make it difficult to employ techniques like supervised machine learning, since it may be impractical to repeatedly produce training sets on short time-scales. Unsupervised machine learning, which does not require training sets, is ideally suited to the morphological analysis of new and forthcoming surveys. Here, we employ an algorithm that performs clustering of graph representations, in order to group image patches with similar visual properties and objects constructed from those patches, like galaxies. We implement the algorithm on the Hyper-Suprime-Cam Subaru-Strategic-Program Ultra-Deep survey, to autonomously reduce the galaxy population to a small number (160) of 'morphological clusters', populated by galaxies with similar morphologies, which are then benchmarked using visual inspection. The morphological classifications (which we release publicly) exhibit a high level of purity, and reproduce known trends in key galaxy properties as a function of morphological type at z < 1 (e.g. stellar-mass functions, rest-frame colours, and the position of galaxies on the star-formation main sequence). Our study demonstrates the power of unsupervised machine learning in performing accurate morphological analysis, which will become indispensable in this new era of deep-wide surveys.
    • Galaxy Populations in Massive Galaxy Clusters to z = 1.1: Color Distribution, Concentration, Halo Occupation Number and Red Sequence Fraction

      Hennig, C.; Mohr, J. J.; Zenteno, A.; Desai, S.; Dietrich, J. P.; Bocquet, S.; Strazzullo, V.; Saro, A.; Abbott, T. M. C.; Abdalla, F. B.; et al. (OXFORD UNIV PRESS, 2017-01-23)
      We study the galaxy populations in 74 Sunyaev-Zeldovich effect selected clusters from the South Pole Telescope survey, which have been imaged in the science verification phase of the Dark Energy Survey. The sample extends up to z similar to 1.1 with 4 x 10(14)M(circle dot) <= M-200 <= 3 x 10(15)M(circle dot). Using the band containing the 4000 angstrom break and its redward neighbour, we study the colour-magnitude distributions of cluster galaxies to similar to m(*) + 2, finding that: (1) The intrinsic rest frame g - r colour width of the red sequence (RS) population is similar to 0.03 out to z similar to 0.85 with a preference for an increase to similar to 0.07 at z = 1, and (2) the prominence of the RS declines beyond z similar to 0.6. The spatial distribution of cluster galaxies is well described by the NFW profile out to 4R(200) with a concentration of c(g) = 3.59(-0.18)(+0.20), 5.37(-0.24)(+0.27) and 1.38(-0.19)(+0.21) for the full, the RS and the blue non-RS populations, respectively, but with similar to 40 per cent to 55 per cent cluster to cluster variation and no statistically significant redshift or mass trends. The number of galaxies within the virial region N-200 exhibits a mass trend indicating that the number of galaxies per unit total mass is lower in the most massive clusters, and shows no significant redshift trend. The RS fraction within R-200 is (68 +/- 3) per cent at z = 0.46, varies from similar to 55 per cent at z = 1 to similar to 80 per cent at z = 0.1 and exhibits intrinsic variation among
    • The GALEX/S4G Surface Brightness and Color Profiles Catalog. I. Surface Photometry and Color Gradients of Galaxies

      Bouquin, Alexandre Y. K.; Gil de Paz, Armando; Muñoz-Mateos, Juan Carlos; Boissier, Samuel; Sheth, Kartik; Zaritsky, Dennis; Peletier, Reynier F.; Knapen, Johan H.; Gallego, Jesús; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-01-25)
      We present new spatially resolved surface photometry in the far-ultraviolet (FUV) and near-ultraviolet (NUV) from images obtained by the Galaxy Evolution Explorer (GALEX) and IRAC1 (3.6 mu m) photometry from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G). We analyze the radial surface brightness profiles mu(FUV), mu(NUV), and mu[3.6], as well as the radial profiles of (FUV - NUV), (NUV -[3.6]), and (FUV -[3.6]) colors in 1931 nearby galaxies (z < 0.01). The analysis of the 3.6 mu m surface brightness profiles also allows us to separate the bulge and disk components in a quasi-automatic way and to compare their light and color distribution with those predicted by the chemo-spectrophotometric models for the evolution of galaxy disks of Boissier & Prantzos. The exponential disk component is best isolated by setting an inner radial cutoff and an upper surface brightness limit in stellar mass surface density. The best-fitting models to the measured scale length and central surface brightness values yield distributions of spin and circular velocity within a factor of two of those obtained via direct kinematic measurements. We find that at a surface brightness fainter than mu([3.6]) = 20.89 mag arcsec(-2), or below 3 x 10(8) M-circle dot kpc(-2) in stellar mass surface density, the average specific star formation rate (sSFR) for star-forming and quiescent galaxies remains relatively flat with radius. However, a large fraction of GALEX Green Valley galaxies show a radial decrease in sSFR. This behavior suggests that an outside-in damping mechanism, possibly related to environmental effects, could be testimony of an early evolution of galaxies from the blue sequence of star-forming galaxies toward the red sequence of quiescent galaxies.
    • Galician coda restrictions and plural clusters

      Colina, S.; Simonet, M.; Univ Arizona, Dept Linguist (WALTER DE GRUYTER, 2014-11)
      The present study investigates the phonology and phonetics of Galician post-vocalic velar nasals. Galician has very strict coda restrictions – it does not allow for complex codas. One exception to this restriction is found in the plurals of words ending in a nasal consonant, which add /s/ to the “right” of a noun or adjective: man ‘hand’, mans ‘hands’; pan ‘bread’, pans ‘breads’. The present study puts forward a proposal, initially based on synchronic, formal phonological grounds, according to which post-vocalic, pre-/s/ nasals in plural forms are not nasal stops, but nasal glides. Their nature as nasal glides allows for their syllabification in the nucleus rather than in the coda, thus preserving (i.e., not violating) the restriction on complex codas. This proposal is then tested with a production experiment based on quantitative acoustic data. The acoustic study reveals indeed a difference in the degree of weakening of post-vocalic nasals, with pre-/s/ nasals in the plural forms showing a significantly higher degree of weakening than pre-/s/ nasals in the singular forms. The article concludes with an Optimality-Theoretic analysis of the phonological facts.
    • Gallbladder Perforation Secondary to Enteric Fever: An Interesting Case of Acute Abdomen

      Malik, Mustafa N; Mahmood, Tayyab; Tameez Ud Din, Asim; Aslam, Shehroz; Imtiaz, Maria; Univ Arizona, Internal Med (CUREUS INC, 2019-04-22)
      Enteric fever is a common infectious disease, especially in countries with poor sanitation and in the tropics. It is caused mainly by Salmonella typhi and accounts for nearly 27 million cases worldwide and 200,000 deaths annually. Enteric fever involves the reticuloendothelial system such as bone marrow, spleen, and liver. As it mostly involves the Peyer's patches of the terminal ileum, enteric perforation occurs commonly. However, gallbladder perforation can also occur, though not very often. Ultrasound as well as computerized tomography (CT) abdomen and pelvis lack specificity for detecting gallbladder perforations in enteric fever. Diagnosis is usually confirmed intraoperatively when the gallbladder is visualized and perforation is seen. Gallbladder perforation is usually seen in acute cholecystitis when the gallbladder becomes necrotic and gangrenous. In acalculous cholecystitis, perforation is rare. Enteric fever is one of the rarest causes of acalculous cholecystitis, leading to perforation. Here, we present the case of a 20-year-old man who presented with fever for 10 days along with loose stools, vomiting, and acute abdomen. Labs showed leukopenia, positive Typhidot test but X-ray erect abdomen and ultrasound abdomen and pelvis were nonspecific. Only after resuscitation and exploration of the abdomen was it found that the gallbladder had multiple perforations. The patient was improved after eight days of postoperative intravenous antibiotics. This is a unique and rare presentation of such a common infectious disease.
    • Gangdese culmination model: Oligocene–Miocene duplexing along the India-Asia suture zone, Lazi region, southern Tibet

      Laskowski, Andrew K.; Kapp, Paul; Cai, Fulong; Univ Arizona, Dept Geosci (GEOLOGICAL SOC AMER, INC, 2018)
      The mechanisms for crustal thickening and exhumation along the Yarlung (IndiaAsia) suture in southern Tibet are under debate, because the magnitudes, relative timing, and interaction between the two dominant structures-the Great Counter thrust and Gangdese thrust-are largely unconstrained. In this study, we present new geologic mapping results from the Yarlung suture zone in the Lazi region, located similar to 350 km west of the city of Lhasa, along with new igneous (5 samples) and detrital (5 samples, 474 ages) U-Pb geochronology data to constrain the crystallization ages of Jurassic- Paleocene Gangdese arc rocks, the provenance of Tethyan Himalayan and Oligocene-Miocene Kailas Formation strata, and the minimum age (ca. 10 Ma) of the Great Counter thrust system. We supplement these data with a compilation of 124 previously published thermochronologic ages from Gangdese batholith, Kailas Formation, and Liuqu Formation rocks, revealing a dominance of 23-15 Ma cooling contemporaneous with slip across the Great Counter thrust system and other potentially linked structures. These data are systematically younger than 98 additional compiled thermochronologic ages from the northern Lhasa terrane, recording mainly Eocene cooling. Structural and thermochronologic data were combined with regional geological constraints, including International Deep Profiling of Tibet and the Himalaya (INDEPTH) seismic reflection data, to develop a new structural model for the Oligocene-Miocene evolution of the Tethyan Himalaya, Yarlung suture zone, and southern Lhasa terrane. We propose that a hinterland-dipping duplex beneath the Gangdese mountains, of which the Gangdese thrust is a component, is kinematically linked with a foreland-dipping passive roof duplex along the Yarlung suture zone, the Great Counter thrust system. The spatial and temporal convergence between the proposed duplex structures along the Yarlung suture zone and the South Tibetan detachment system indicate that they may be kinematically linked, though this relationship is not directly addressed in this study. Our interpretation, referred to as the Gangdese culmination model, explains why the Gangdese thrust system is only locally exposed (at relatively deeper structural levels) and provides a structural explanation for early Miocene crustal thickening along the Yarlung suture zone, relief generation along the modern Gangdese Mountains, early Miocene Yarlung River establishment, and creation of the modern internal drainage boundary along the southern Tibetan Plateau. The progression of deformation along the suture zone is consistent with tectonic models that implicate subduction dynamics as the dominant control on crustal deformation.
    • The Gao-Guenie impact melt breccia-Sampling a rapidly cooled impact melt dike on an H chondrite asteroid?

      Swindle, Timothy D.; Schmieder, Martin; Kring, David A.; Bond, Jade C.; Moore, Carleton B.; Univ Arizona, Lunar & Planetary Lab (WILEY-BLACKWELL, 2016-06)
      The Gao-Guenie H5 chondrite that fell on Burkina Faso (March 1960) has portions that were impact-melted on an H chondrite asteroid at similar to 300 Ma and, through later impact events in space, sent into an Earth-crossing orbit. This article presents a petrographic and electron microprobe analysis of a representative sample of the Gao-Guenie impact melt breccia consisting of a chondritic clast domain, quenched melt in contact with chondritic clasts, and an igneous-textured impact melt domain. Olivine is predominantly Fo(80-82). The clast domain contains low-Ca pyroxene. Impact melt-grown pyroxene is commonly zoned from low-Ca pyroxene in cores to pigeonite and augite in rims. Metal-troilite orbs in the impact melt domain measure up to similar to 2 mm across. The cores of metal orbs in the impact melt domain contain similar to 7.9 wt% of Ni and are typically surrounded by taenite and Ni-rich troilite. The metallography of metal-troilite droplets suggest a stage I cooling rate of order 10 degrees C s(-1) for the superheated impact melt. The subsolidus stage II cooling rate for the impact melt breccia could not be determined directly, but was presumably fast. An analogy between the Ni rim gradients in metal of the Gao-Guenie impact melt breccia and the impact-melted H6 chondrite Orvinio suggests similar cooling rates, probably on the order of similar to 5000-40,000 degrees C yr(-1). A simple model of conductive heat transfer shows that the Gao-Guenie impact melt breccia may have formed in a melt injection dike similar to 0.5-5 m in width, generated during a sizeable impact event on the H chondrite parent asteroid.
    • Gap controlled plasmon-dielectric coupling effects investigated with single nanoparticle-terminated atomic force microscope probes

      Huang, Qian; Teran Arce, Fernando; Lee, Joon; Yoon, Ilsun; Villanueva, Joshua; Lal, Ratnesh; Sirbuly, Donald J.; Univ Arizona, Dept Biomed Engn, Dept Med, Div Translat & Regenerat Med (ROYAL SOC CHEMISTRY, 2016-09-13)
      Precise positioning of a plasmonic nanoparticle (NP) near a small dielectric surface is not only necessary for understanding gap-dependent interactions between a metal and dielectric but it is also a critical component in building ultrasensitive molecular rulers and force sensing devices. In this study we investigate the gap-dependent scattering of gold and silver NPs by controllably depositing them on an atomic force microscope (AFM) tip and monitoring their scattering within the evanescent field of a tin dioxide nanofiber waveguide. The enhanced distance-dependent scattering profiles due to plasmon-dielectric coupling effects show similar decays for both gold and silver NPs given the strong dependence of the coupling on the decaying power in the near-field. Experiments and simulations also demonstrate that the NPs attached to the AFM tips act as free NPs, eliminating optical interference typically observed from secondary dielectric substrates. With the ability to reproducibly place individual plasmonic NPs on an AFM tip, and optically monitor near-field plasmon-dielectric coupling effects, this approach allows a wide-variety of light-matter interactions studies to be carried out on other low-dimensional nanomaterials.
    • Gas Dynamics of a Luminous z = 6.13 Quasar ULAS J1319+0950 Revealed by ALMA High-resolution Observations

      Shao, Yali; Wang, Ran; Jones, Gareth C.; Carilli, Chris L.; Walter, Fabian; Fan, Xiaohui; Riechers, Dominik A.; Bertoldi, Frank; Wagg, Jeff; Strauss, Michael A.; et al. (IOP PUBLISHING LTD, 2017-08-18)
      We present new Atacama Large Millimeter/submillimeter Array (ALMA) observations of the dust continuum and [C II] 158 mu m fine structure line emission toward a far-infrared-luminous quasar, ULAS J131911.29+095051.4 at z = 6.13, and combine the new Cycle 1 data with ALMA Cycle 0 data. The combined data have an angular resolution of similar to 0.'' 3, and resolve both the dust continuum and the [C II] line emission on a few kiloparsec scales. The [C II] line emission is more irregular than that of the dust continuum emission, which suggests different distributions between the dust and the [C II] emitting gas. The combined data confirm the [C II] velocity gradient that we had previously detected in a lower-resolution ALMA image from the Cycle 0 data alone. We apply a tilted ring model to the [C II] velocity map to obtain a rotation curve, and constrain the circular velocity to be 427 +/- 55 kms(-1) at a radius of 3.2 kpc with an inclination angle of 34 degrees. We measure the dynamical mass within the 3.2 kpc region to be 13.4(-5.3)(+7.8) x 10(10) M-circle dot. This yields a black-hole and host galaxy mass ratio of 0.020(-0.007)(+0.013), which is about 4(-2)(+3) times higher than that of the present-day M-BH/M-bulge ratio. This suggests that the supermassive black hole grows the bulk of its mass before the formation of most of the stellar mass in this quasar host galaxy in the early universe.