The Hera orebody: a complex distal (Au–Zn–Pb–Ag–Cu) skarn in the Cobar Basin of central New South Wales, Australia

The Hera Au–Pb–Zn–Ag deposit in the southeastern Cobar Basin of central New South Wales preserves calc-silicate veins and remnant sandstone/carbonate-hosted skarn within a reduced anchizonal Siluro-Devonian turbidite sequence. The skarn orebody distribution is controlled by a long-lived, basin margin fault system, that has intersected a sedimentary horizon dominated by siliciclastic turbidite, with lesser gritstone and thick sandstone intervals, and rare carbonate-bearing stratigraphy. Foliation (S1) envelopes the orebody and is crosscut by a series of late-stage east–west and north–south trending faults. Skarn at Hera displays mineralogical zonation along strike, from southern spessartine–grossular–biotite–actinolite-rich associations, to central diopside-rich–zoisite–actinolite/tremolite–grossular-bearing associations, through to the northern most tremolite–anorthite-rich (garnet-absent) association in remnant carbonate-bearing lithologies and sandstone horizons; the northern lodes also display zonation down dip to garnet present associations. High-T, prograde skarn assemblages rich in pyroxene and garnet are pervasively replaced by actinolite/tremolite–biotite-rich retrograde skarn which coincides with the main pulse of sulfide mineralization. The dominant sulfides are high-Fe–Mn sphalerite–galena–non-magnetic high-Fe pyrrhotite–chalcopyrite; pyrite, arsenopyrite; scheelite (low Mo) is locally abundant. The distribution of metals in part mimics the changing gangue mineralogy, with Au concentrated in the southern and lower northern lode systems and broadly inverse concentrations for Ag–Pb–Zn. Stable isotope data (O–H–S) from skarn amphiboles and associated sulfides are consistent with magmatic (or metamorphic) water and sulfur input during the retrograde skarn phase, while hydrosilicates and sulfides from the wall rocks display comparatively elevated δD and mixed δ34S consistent with progressive mixing or dilution of original magmatic (or metamorphic) waters within the Hera deposit by unexchanged waters typical of low latitude (tropical) meteoritic waters. High precision titanite (U–Pb) and biotite (Ar–Ar) geochronology reveals a manifold orebody commencing with high-T skarn and retrograde Pb–Zn-rich skarn formation at ≥403 Ma, Au–low-Fe sphalerite mineralization at 403.4 ± 1.1 Ma, foliation development remobilization or new mineralization at 390 ± 0.2 Ma followed by thrusting, orebody dismemberment at 384.8 ± 1.1 Ma and remobilization or new mineralization at 381.0 ± 2.2 Ma. The polymetallic nature of the Hera orebody is a result of multiple mineralization events during extension and compression and involving both magmatic and likely formational metal sources

In vivo assessment of diet-induced rat hepatic steatosis development by percutaneous single-fiber spectroscopy detects scattering spectral changes due to fatty infiltration

This study explores percutaneous single-fiber spectroscopy (SfS) of rat livers undergoing fatty infiltration. Eight test rats were fed a methionine-choline-deficient (MCD) diet, and four control rats were fed a normal diet. Two test rats and one control rat were euthanized on days 12, 28, 49, and 77 following initiation of the diet, after percutaneous SfS of the liver under transabdominal ultrasound guidance. Histology of each set of the two euthanized test rats showed mild and mild hepatic lipid accumulations on day 12, moderate and severe on day 28, severe and mild on day 49, and moderate and mild on day 77. Livers with moderate or higher lipid accumulation generally presented higher spectral reflectance intensity when compared to lean livers. Livers of the eight test rats on day 12, two of which had mild lipid accumulation, revealed an average scattering power of 0.37±0.14 in comparison to 0.07±0.14 for the four control rats (p<0.01). When livers of the test rats with various levels of fatty infiltration were combined, the average scattering power was 0.36±0.15 in comparison to 0.14±0.24 of the control rats (0.05<p<0.1). Increasing lipid accumulation in concentration and size seemed to cause an increase of the scattering power prior to increasing total spectral reflectance.Electrical and Computer EngineeringVeterinary Clinical Science

In vivo percutaneous reflectance spectroscopy of fatty liver development in rats suggests that the elevation of the scattering power is an early indicator of hepatic steatosis

This study assessed whether there was a scattering spectral marker quantifiable by reflectance measurements that could indicate early development of hepatic steatosis in rats for potential applications to pre-procurement organ evaluation. Sixteen rats were fed a methionine-choline-deficient (MCD) diet and eight rats were fed a normal diet. Direct assessment of the liver parenchyma of rats in vivo was performed by percutaneous reflectance spectroscopy using a single fiber probe at the beginning of diet-intake and arbitrary post-diet-intake times up to 11 weeks to render longitudinal comparison. Histological sampling of the liver over the duration of diet administration was performed on two MCD-diet treated rats and one control rat euthanized after reflectance spectroscopy measurement. The images of hematoxylin/eosin-stained liver specimens were analyzed morphometrically to evaluate the lipid size changes associated with the level of steatosis. The MCD-diet-treated group (n=16) had mild steatosis in seven rats, moderate in three rats, severe in six rats, and no other significant pathology. No control rats (n=8) developed hepatic steatosis. Among the parameters retrieved from per-SfS, only the scattering power (can be either positive or negative) appeared to be statistically different between MCD-treated and control livers. The scattering power for the 16 MCD-diet-treated livers at the time of euthanasia and presenting various levels of steatosis was 0.33±0.21, in comparison to 0.036±0.25 of the eight control livers (p=0.0189). When evaluated at days 12 and 13 combined, the scattering power of the 16 MCD-diet-treated livers was 0.32±0.17, in comparison to 0.10±0.11 of the eight control livers (p=0.0017). All of four MCD-treated livers harvested at days 12 and 13 presented mild steatosis with sub-micron size lipid droplets, even though none of the MCD-treated livers were sonographically remarkable for fatty changes. The elevation of the scattering power may be a valuable marker indicating early hepatic steatosis before the steatosis is sonographically detectable.Electrical and Computer EngineeringVeterinary Clinical Science

Pharmacological Analysis of the Activation and Receptor Properties of the Tonic GABACR Current in Retinal Bipolar Cell Terminals

GABAergic inhibition in the central nervous system (CNS) can occur via rapid, transient postsynaptic currents and via a tonic increase in membrane conductance, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs) respectively. Retinal bipolar cells (BCs) exhibit a tonic current mediated by GABACRs in their axon terminal, in addition to synaptic GABAAR and GABACR currents, which strongly regulate BC output. The tonic GABACR current in BC terminals (BCTs) is not dependent on vesicular GABA release, but properties such as the alternative source of GABA and the identity of the GABACRs remain unknown. Following a recent report that tonic GABA release from cerebellar glial cells is mediated by Bestrophin 1 anion channels, we have investigated their role in non-vesicular GABA release in the retina. Using patch-clamp recordings from BCTs in goldfish retinal slices, we find that the tonic GABACR current is not reduced by the anion channel inhibitors NPPB or flufenamic acid but is reduced by DIDS, which decreases the tonic current without directly affecting GABACRs. All three drugs also exhibit non-specific effects including inhibition of GABA transporters. GABACR ρ subunits can form homomeric and heteromeric receptors that differ in their properties, but BC GABACRs are thought to be ρ1-ρ2 heteromers. To investigate whether GABACRs mediating tonic and synaptic currents may differ in their subunit composition, as is the case for GABAARs, we have examined the effects of two antagonists that show partial ρ subunit selectivity: picrotoxin and cyclothiazide. Tonic and synaptic GABACR currents were differentially affected by both drugs, suggesting that a population of homomeric ρ1 receptors contributes to the tonic current. These results extend our understanding of the multiple forms of GABAergic inhibition that exist in the CNS and contribute to visual signal processing in the retina

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Comparative imaging of canine shoulder osteochondrosis lesions

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on July 14, 2010).Thesis advisor: Cristi R. Cook."May 2010"M.S. University of Missouri-Columbia 2010.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Over the last several years, papers have been published describing imaging techniques for the canine shoulder joint using both ultrasound and magnetic resonance imaging, with osteochondrosis lesions being described to varying degrees. This prospective study directly compared radiographs, ultrasound, and magnetic resonance imaging, to arthroscopic findings of a larger, clinically affected, population of dogs with osteochondral lesions. The findings of this study determined the diagnostic accuracy of radiographic, ultrasonographic, and magnetic resonance imaging in canine shoulder osteochondrosis. These findings enable the clinician to objectively choose the most effective imaging modality or modalities in order to obtain a comprehensive and accurate diagnosis of shoulder osteochondrosis to help determine and plan surgical treatment. The amount of information needed will depend on the patient, the surgeon and the surgical technique utilized for the treatment of canine shoulder osteochondrosis. Overall magnetic resonance imaging had the strongest correlation to the surgically identified lesion. A sagittal T2 or PD FAT SAT magnetic resonance sequence was the most useful modality at ruling out an osteochondral lesion and can be used to avoid an exploratory arthroscopic surgery of the canine shoulder.Includes bibliographical references (pages 82-87)

Catastrophic complication following injection and extracorporeal shock wave therapy of a medial femoral condyle subchondral cystic lesion in a 14 year old Arabian mare

This report describes fibrous cyst lining injection and extracorporeal shock wave therapy (ESWT) of a medial femoral condyle (MFC) subchondral cystic lesion (SCL) resulting in  atastrophic MFC fracture in an Arabian mare. The mare was presented for evaluation of a severe hind limb lameness of approximately 4 months duration. On presentation, a non-weight bearing lameness of the left hind limb with severe effusion and soft tissue swelling of the stifle region was noted. Radiographic evaluation of the stifle revealed a large SCL of the MFC with associated osteoarthritis. Arthroscopic guided intra-lesional injection of the SCL with  corticosteroids and autologous bone marrow concentrate was performed followed by ESWT of the MFC. The mare was discharged walking comfortably 48-hours post-operatively. An acute increase in lameness was noted 14 days post-operatively. Imaging revealed catastrophic fracture of the left MFC. Possible mechanisms leading to failure of the MFC secondary to the described treatment are discussed.Keywords: Equine, Extracorporeal shock wave therapy, Intra-lesional injection, Stifle, Subchondral cystic lesion

In vivo percutaneous reflectance spectroscopy of fatty liver development in rats suggests that the elevation of the scattering power is an early indicator of hepatic steatosis

This study assessed whether there was a scattering spectral marker quantifiable by reflectance measurements that could indicate early development of hepatic steatosis in rats for potential applications to pre-procurement organ evaluation. Sixteen rats were fed a methionine-choline-deficient (MCD) diet and eight rats were fed a normal diet. Direct assessment of the liver parenchyma of rats in vivo was performed by percutaneous reflectance spectroscopy using a single fiber probe at the beginning of diet-intake and arbitrary post-diet-intake times up to 11 weeks to render longitudinal comparison. Histological sampling of the liver over the duration of diet administration was performed on two MCD-diet treated rats and one control rat euthanized after reflectance spectroscopy measurement. The images of hematoxylin/eosin-stained liver specimens were analyzed morphometrically to evaluate the lipid size changes associated with the level of steatosis. The MCD-diet-treated group (n=16) had mild steatosis in seven rats, moderate in three rats, severe in six rats, and no other significant pathology. No control rats (n=8) developed hepatic steatosis. Among the parameters retrieved from per-SfS, only the scattering power (can be either positive or negative) appeared to be statistically different between MCD-treated and control livers. The scattering power for the 16 MCD-diet-treated livers at the time of euthanasia and presenting various levels of steatosis was 0.33±0.21, in comparison to 0.036±0.25 of the eight control livers (p=0.0189). When evaluated at days 12 and 13 combined, the scattering power of the 16 MCD-diet-treated livers was 0.32±0.17, in comparison to 0.10±0.11 of the eight control livers (p=0.0017). All of four MCD-treated livers harvested at days 12 and 13 presented mild steatosis with sub-micron size lipid droplets, even though none of the MCD-treated livers were sonographically remarkable for fatty changes. The elevation of the scattering power may be a valuable marker indicating early hepatic steatosis before the steatosis is sonographically detectable

Integrating Zircon Trace-Element Geochemistry and High-Precision U-Pb Zircon Geochronology to Resolve the Timing and Petrogenesis of the Late Ediacaran–Cambrian Wichita Igneous Province, Southern Oklahoma Aulacogen, USA

The bimodal Wichita igneous province (WIP) represents the only exposed Ediacaran to Cambrian anorogenic magmatic assemblage present along the buried southern margin of Laurentia and was emplaced during rifting in the Southern Oklahoma Aulacogen prior to Cambrian opening of the southern Iapetus Ocean. Here, we establish the first high-precision U-Pb zircon geochronological framework for the province. Weighted mean 206Pb/238U dates from mafic and felsic rocks in the Wichita Mountains indicate emplacement in a narrow time frame from 532.49 ± 0.12 Ma to 530.23 ± 0.14 Ma. Rhyolite lavas in the Arbuckle Mountains farther east yield weighted mean 206Pb/238U dates of 539.20 ± 0.15 Ma and 539.46 ± 0.13 Ma. These dates for the WIP indicate that magmatism in the Southern Oklahoma Aulacogen postdated the ca. 540 Ma rift-drift transition along the Appalachian margin to the east. Whole-rock trace-element and isotopic geochemistry, supplemented by trace elements in zircon, tracks the evolution of magma sources during WIP petrogenesis. These data indicate that initial melting and assimilation of subcontinental mantle lithosphere by an uprising mantle plume were followed by increasing involvement of asthenospheric melts with time. We suggest that upwelling of this plume in the area of the Southern Oklahoma Aulacogen triggered an inboard jump of the spreading center active along the eastern margin of Laurentia, which led to separation of the Precordillera terrane (now located in Argentina) from the Ouachita embayment present in the southern Laurentian margin