bluuebunny/crossref_metadata_2025 huggingface dataset:
New sites of Chengjiang fossils: crucial windows on the Cambrian explosion
Authors: ZHANG XINGLIANG , SHU DEGAN , LI YONG , HAN JIAN
Published: June 2010

Soft-bodied and lightly sclerotized Chengjiang fossils have been found at more than ten new localities in the Lower Cambrian Qiongzhusi and Canglangpu formations of east central Yunnan. At the same time, three different fossil assemblages have been recognized, i.e.
Kunmingella–Isoxys–Naraoia
assemblage at Chengjiang,
Kunmingella
–
Cricocosmia
assemblage at Haikou, and
Kunmingella
–
Wutingaspis
–
Obolus
assemblage at Anning and Wuding. These sites yield new and striking specimens, such as a new tentacular animal, brachiopods with pedicles preserved, and the enigmatic
Xidazoon
(having mixed phyla characters), which are significant in our understanding of animal phylogeny. Above all, the appearance of diverse chordates and agnathans (vertebrates) greatly expands our knowledge of the Cambrian explosion. The discovery of soft-bodied fossils at many new localities and the very wide distribution of the Qiongzhusi Formation suggest that many more localities remain to be discovered. Here, a new early form of tentaculate,
Cambrotentacus sanwuia
gen. et sp. nov. (perhaps related to lophophorates and entoprocts), is described.
Fluid-enhanced melting during prograde metamorphism
Authors: PRINCE C. , HARRIS N. , VANCE D.
Published: June 2010

Anatexis is a commonly recognized feature of high-grade metamorphism, but segregated melts are generally ascribed to anatexis during peak metamorphic conditions and little is known about melting along the prograde path. A suite of small-volume, deformed, two-mica leucogranites has been recognized within the High Himalayan Crystalline Series of the Garhwal Himalaya. These granites are consistently more siliceous than minimum-melt granite compositions and are characterized by low Rb/Sr ratios, high Ba, low abundances of HFS elements and positive Eu anomalies. Such trace-element characteristics contrast strongly with the geochemistry of the well-studied Early Miocene leucogranites of the High Himalaya, derived from fluid-absent melting. Sm–Nd garnet dating of one deformed granite indicates a crystallization age of 39±3 Ma,
c.
 15 Ma before the emplacement of the more voluminous High Himalayan leucogranites. Whilst some entrainment of restitic phases cannot be excluded, trace element signatures suggest a low temperature (<650°C) crustal melt formed under conditions of high H
2
O activity. Positive Eu anomalies and unusually low Rb/Sr ratios are indicative of rapid, disequilibrium melting.

Fluid-enhanced melting may be a common feature of prograde upper amphibolite-facies metamorphism of orogenic belts, predating peak metamorphism by at least 15 Ma. These melts will only crystallize within this period if they segregate from their protoliths. Subsequent dating of long-lived melts would indicate erroneously young ages for the prograde melting events. However, melts formed in this way may be recognized by their distinctive trace-element chemistry. The persistence of early formed melts within an orogen provides insights into the prograde heating path, and may be critical in controlling the rheology of the middle crust, and hence its deformational history.
U–Pb geochronological constraints on the timing of plutonism, volcanism, and sedimentation, Jersey, Channel Islands, UK
Authors: MILLER BRENT V. , SAMSON SCOTT D. , D’LEMOS RICHARD S.
Published: June 2010

Uranium–lead dates for single and small multiple grain zircon separates are presented for the main geological units from Jersey, British Channel Islands. A turbiditic sandstone from the Jersey Shale Formation (Brioverian Supergroup) contains detrital zircons of a variety of ages, ranging from
c.
 2.6 to 0.6 Ga. The youngest zircons yielded nearly concordant U–Pb dates of 586.7±3.0 Ma and 587.1±2.7 Ma providing a maximum depositional age for the unit. Zircons from overlying volcanic rocks (Anne Port Rhyolite) give an upper intercept date of 582.8
+3
−2.7
 Ma, considered to be the age of eruption. The undeformed SW Jersey granite, which intrudes and locally thermally metamorphoses the folded Jersey Shale Formation, is dated at 580
+2.3
−1.6
 Ma. These dates constrain tightly the timing of deposition of the Jersey Shale Formation and the age of deformation on Jersey, and indicate a dynamic arc environment during the late Neoproterozoic. Zircons from the NW Jersey granite define an upper intercept date of 482.7±1.6 Ma, similar to the previously reported
40
Ar/
39
Ar hornblende date of
c.
 473 Ma, confirming a renewed pulse of magmatism during the Ordovician in this sector of Cadomia.
New evidence for a large Palaeoproterozoic impact: spherules in a dolomite layer in the Ketilidian orogen, South Greenland
Authors: CHADWICK BRIAN , CLAEYS PHILIPPE , SIMONSON BRUCE
Published: June 2010

An unconformable sedimentary succession deposited between
c.
 2130–1848 Ma on Archaean gneisses of the foreland of the Palaeoproterozoic Ketilidian orogen includes a layer with coarse sand-sized silicate spherules. The layer is
c.
 1 m thick and consists mainly of coarse diagenetic dolomite. In addition to
c.
 18% spherules, the layer also contains 3% well-sorted, very fine quartzose sand and 6% larger intraclasts of chert and carbonate. The spherules were previously interpreted as microfossils (
Vallenia
sp.) because of their spheroidal shapes and inclusions of carbonaceous matter. The spherules are reinterpreted as replaced impact ejecta because they have shapes typical of splash-form microtektites, some contain possible examples of replaced skeletal spinel crystals, perlitic cracks and devitrification spherulites, and non-spherical particles with shapes and textures of typical glassy and scoriaceous volcanic ash are absent. The carbonaceous matter is attributed to hydrocarbons that migrated into the spherule layer from elsewhere in the sedimentary succession. The spherules were reworked after deposition, probably as a result of turbidity currents or storm- or impact-induced waves. Analysis of one spherule-bearing sample revealed only 0.02 ppb iridium, a value comparable with low iridium abundances in distal layers of other terrestrial impact ejecta. The spherules in South Greenland are the first distal impact ejecta recognized in mid-Precambrian strata. They represent a major impact because their aggregate thickness exceeds the thickest spherule accumulations reported from the Cretaceous-Tertiary boundary layer. Given their loosely constrained age and the implied scale of the impact, the Ketilidian spherules could be distal ejecta from either the Vredefort, South Africa, (
c.
 2025 Ma) or Sudbury, Canada, (
c.
 1850 Ma) impacts.
Coseismic displacements along the Serghaya Fault: an active branch of the Dead Sea Fault System in Syria and Lebanon
Authors: GOMEZ F. , MEGHRAOUI M. , DARKAL A. N. , SBEINATI R. , DARAWCHEH R. , TABET C. , KHAWLIE M. , CHARABE M. , KHAIR K. , BARAZANGI M.
Published: June 2010

Examination of the Serghaya fault, a branch of the Dead Sea Fault System in western Syria and eastern Lebanon, documents Late Quaternary and Recent left-lateral fault movements including the probable remnant of a historic coseismic surface rupture. Carbon-14 dating and the presence of fault-scarp free faces in soft, late Pleistocene lake deposits suggest coseismic slip during the past two or three centuries, possibly corresponding with one of the well-documented earthquakes of 1705 or 1759. With an estimated Holocene slip rate of 1–2 mm a
−1
, the Serghaya Fault accommodates a significant part of the active deformation along the Arabian–African plate boundary. These results suggest that multiple active fault branches are involved in the transfer of strain through the ‘Lebanese’ restraining bend.
Deep-marine seabed erosion and gravel lags in the northwestern Rockall Trough, North Atlantic Ocean
Authors: HOWE JOHN A. , STOKER MARTYN S. , WOOLFE KEN J.
Published: June 2010

A zone of active seabed erosion has been identified in the northwestern Rockall Trough using seismic reflection profiles and cores. The region from George Bligh Bank to Rockall Bank has been subject to vigorous bottom-current activity, for at least the last 35 Ma. Bottom currents originate from southward flowing North Atlantic Deep Water, in water depths of 500–2000 m. Acoustic character mapping reveals a zone of erosion extending over 8500 km
2
along the northwestern margins of the trough. The erosion surface is characterized by an acoustically reflective seabed, with occasional parallel to transparent reflectors. These are the result of strong bottom-currents exposing the underlying volcanic basement, drift sequences and fan sediments. The erosion surface is covered by a <10 m veneer of Quaternary sediment. The majority of the basin consists of well-stratified, parallel Quaternary drift and hemipelagite sequences. Along the western margin of the trough, these sediments form broad-sheeted drifts. Eocene sediments adjacent to George Bligh Bank have been exposed by strong bottom-currents for the last 35 Ma, compared with the flanks of Rockall Bank, where sedimentation was intermittent. Core sampling from George Bligh Bank and Rockall Bank recovered Quaternary gravelly–sandy muds interpreted as gravel lags, and muddy sandy contourites, overlying early–mid-Eocene aged sediments. The gravels represent the influence of a strongest North Atlantic Deep Water flow, winnowing coarse sediment into ‘lags’, commonly preserved within sandy contourite sequences.
Kinematic linkage between internal zone extension and shortening in more external units in the NW Alps
Authors: WHEELER J. , REDDY S. M. , CLIFF R. A.
Published: June 2010

In the Alps a major extensional shear zone unroofed eclogites in its footwall from 30 kbar to
c.
 10 kbar, implying of the order of 60 km of relative vertical movement in the period 45–36 Ma. The horizontal component of divergence was of the order of 100 km. We use the foreland basin sedimentary record to prove that the extension was contemporaneous with thrusting in units structurally beneath the eclogites (the Briançonnais and/or External Zones). This thrust-related convergence during that time period was of the order of 44–56 km and therefore of the same order of magnitude as internal zone divergence. Extension may have been driven by internal density contrasts. Buoyant continental crust underneath the mafic eclogites, or dense subducted slab offset from the orogen, can induce extension. Any dynamic model must account for the comparable magnitudes of extension and shortening in adjacent parts of the orogen: relative plate motions in the period 45–36 Ma played a subsidiary role.
Structural and lithological characteristics of the Bayankhongor Ophiolite Zone, Central Mongolia
Authors: BUCHAN CRAIG , CUNNINGHAM DICKSON , WINDLEY BRIAN F. , TOMURHUU D.
Published: June 2010

The mechanism of continental growth of Central Asia is currently debated between models invoking continuous subduction–accretion, or punctuated accretion due to closure of multiple ocean basins. Ophiolites in Central Asia may represent offscraped fragments in an accretionary complex or true collisional sutures. The Bayankhongor ophiolite, a NW–SE-striking sublinear belt 300 km long and 20 km wide, is the largest ophiolite in Mongolia and possibly Central Asia. We present results of the first detailed structural and lithological study of the ophiolite. The study area is divided into four zones: Baidrag complex, Burd Gol, Bayankhongor, and Dzag zones. The Archaean Baidrag complex comprises tonalitic granulites and metasediments. The Burd Gol zone is a metamorphosed sedimentary and igneous mélange. The Bayankhongor zone contains the dismembered ophiolite forming a serpentinite mélange. The Dzag zone consists of asymmetrically folded chlorite–mica schists resembling meta-turbidites. The structure is dominated by steeply dipping, NE directed thrusts and NE-vergent folds. We suggest the Bayankhongor ophiolite marks the closure of an ocean separating two microcontinents: the Baidrag complex with the Burd Gol accretionary complex to the south, and a northern continent that forms the basement for the Hangai region. Subduction was towards the SW with NE-directed ophiolite obduction onto a passive margin represented by the Dzag zone.
Dating deformation and cooling in the Caledonian thrust nappes of north Sutherland, Scotland: insights from
40
Ar/
39
Ar and Rb–Sr chronology
Authors: DALLMEYER R. D. , STRACHAN R. A. , ROGERS G. , WATT G. R. , FRIEND C. R. L.
Published: June 2010

40
Ar/
39
Ar and Rb–Sr mineral ages have been determined from various lithologies exposed in the Caledonian foreland and structurally overlying thrust nappes of north Sutherland, Scotland. Rb–Sr muscovite ages of
c
. 428,
c
. 421 and
c
. 413 Ma obtained from Moine Thrust Zone mylonites are interpreted to date closely regional thrusting during the Late Silurian to Early Devonian.
40
Ar/
39
Ar muscovite ages within the lower parts of the Moine nappe are mostly anomalously old with respect to Rb–Sr analyses of muscovites from the same samples; it is likely that this discrepancy results from a component of extraneous or ‘excess’ argon.
40
Ar/
39
Ar hornblende ages and Rb–Sr and
40
Ar/
39
Ar muscovite ages obtained from structurally higher metamorphic units in the Caledonian thrust nappes generally range between
c
. 440 Ma and
c
. 410 Ma. These ages are interpreted to date cooling during and following ‘D
2
’ regional thrusting and folding within internal sectors of the nappe sequence. A possible tectonic model involves the Silurian collision of Baltica with Scottish segments of Laurentia resulting in the Scandian orogeny and broadly coeval Moine Thrust Zone. D
2
structures were superimposed on structures and metamorphic fabrics formed during a regional Mid-Ordovician tectonothermal event dated previously at
c
. 470–460 Ma. Syn-D
2
temperatures were generally >600°C and sufficient to achieve more or less complete thermal rejuvenation of Rb–Sr and
40
Ar/
39
Ar isotopic systems in muscovite and hornblende, even in areas of low D
2
strain.
Geochronological constraints on tectonic models for Australian Palaeoproterozoic high-K granites
Authors: PAGE R. W. , GRIFFIN T. J. , TYLER I. M. , SHEPPARD S.
Published: June 2010

High-K granites extensively intruded all the Palaeoproterozoic terrains of northern Australia, and have been interpreted as the culmination of widespread intracratonic orogeny. One of these terrains, the Lamboo Complex, developed between the Kimberley and North Australian Cratons. The complex is divided into three terranes, referred to as the Western, Central, and Eastern zones, and was intruded by a variety of I-type granites and gabbros. High-K granites of the 1865–1850 Ma Paperbark supersuite are restricted to the Western zone. Tonalite sheets of the Dougalls suite, and unassigned leucogranite sheets, intruded the Central zone at
c.
 1850 Ma. The 1835–1805 Ma Sally Downs supersuite is composed of tonalite and high-K granite that mainly intruded the Central zone. However, high-K granites of the Sally Downs supersuite intruded all three zones from
c.
 1820 Ma onwards, and mark the amalgamation of the terranes. The youngest granites in the complex are high-K granites of the 1805–1790 Ma San Sou suite, which intrude the Eastern and Central zones. The temporal and spatial distribution of the granites is not easily reconciled with previous intracratonic models, but is consistent with tectonic processes similar to those operating at present.
Time seismicity patterns affecting local and regional fault systems in the Etna region: preliminary results for the period 1874–1913
Authors: AZZARO R. , BARBANO M. S. , RIGANO R. , VINCIGUERRA S.
Published: June 2010

An analysis of time correlation function and fractal dimension has been performed on the seismic activity that affected Mt Etna Volcano (Italy) during 1874–1913 in order to investigate the behaviour of some suspected magma controlling regional fault systems. The time span considered has been characterized by intense seismic and volcanic activity, with eight flank eruptions mainly occurring along the same north–south fissure system. The analysis of historical sources has been used to revise and improve the seismic catalogue; all macroseismic information has been reinterpreted using the new European Macroseismic Scale 1998 (EMS). The results contribute to the definition of the seismic behaviour of some regional fault systems relevant to the geodynamics of the area and provide some insights into the dynamic processes of Mt Etna volcano.
Relocating and orientating cores by the integration of electrical and optical images: a case study from Ocean Drilling Program Hole 735B
Authors: HAGGAS S. L. , BREWER T. S. , HARVEY P. K. , ITURRINO G. I.
Published: June 2010

While the dip of structural features on recovered rotary-drilled core can be accurately measured, the azimuth of such features in a geographical reference frame is not known. Scribing techniques and analysis of magnetic signatures have been used in attempts to solve this problem, but scribing has so far failed in deep-sea drilling operations and magnetic signatures cannot always be easily resolved. Here, we demonstrate a method for core reorientation and accurate location within a borehole using a comparison between borehole electrical images and whole-core digital images.

ODP Hole 735B penetrates a 1500 m section of lower oceanic crustal (gabbroic) rocks with an average core recovery of 86.6%. The absence of orientated core pieces severely restricts the interpretation of these data. In this study, the entire outer surface of individual core pieces was scanned using the DMT Digital Colour CoreScan™ system. Structural features on these unrolled digital images are correlated with images of the same features on Formation Microscanner logs obtained during the wireline-logging programme. Using this approach it is possible to reorientate and accurately locate core pieces within the drilled section.
Rotation of ductile fabrics across the Alpine Fault and Cenozoic bending of the New Zealand orocline
Authors: LITTLE TIMOTHY A. , MORTIMER NICK
Published: June 2010

This study examines the role and kinematic mechanism of vertical‐axis rotations and folding during early development phases of a transform plate boundary in continental crust. Near the Alpine Fault in New Zealand, this involved an initial period of widely distributed shear (including wrench folding), together with vertical‐axis rotations and orocline development, followed by a focusing of slip onto a single fault. In the South Island, the Haast Schist has been displaced horizontally in the Neogene by
c. 
480 km of dextral‐slip on the Alpine Fault. LS tectonites on either side of the fault lie on different limbs of a profound Z‐shaped orocline. Rotation of these limbs took place about a vertical axis, resulting in 25–30° of clockwise rotation of fabrics to the NW of the Alpine Fault relative to those to the south. Foliation anisotropy caused bending to take place locally by folding about an inclined hinge in the limbs of a pre‐existing synform, which tightened during the deformation. On both sides of the fault, involvement of post‐Oligocene age structures in wrench‐folding and bending suggests that the bending took place entirely in the Cenozoic, before or during Miocene development of the Alpine Fault as a through‐going structure. During this early phase of plate boundary deformation, shear was distributed across a zone >100 km wide. Vertical‐axis rotation affected, fault‐bounded basement slivers that shortened perpendicular to their strike, a style of deformation like that in the Transverse Ranges in California today.
How to resist subduction: evidence for large-scale out-of-sequence thrusting during Eocene collision in western Turkey
Authors: GESSNER KLAUS , RING UWE , PASSCHIER CEES W. , GÜNGÖR TALIP
Published: June 2010

Significant along-strike variations have locked large parts of the Alpine subduction complex in the Eastern Mediterranean in the Eocene, and defined the end of high-pressure accretion in western Turkey. Structural analysis reveals that the Anatolide belt in western Turkey formed under greenschist facies metamorphic conditions in the Eocene when a high-pressure metamorphic fragment of the Adriatic plate (the Cycladic blueschist unit) was thrust onto the imbricated mid-crustal units of the Anatolian microcontinent (the Menderes nappes). The contact between the Cycladic blueschist unit and the Menderes nappes, the Cyclades–Menderes thrust, represents an out-of-sequence ramp which cuts up-section towards the south. The lack of Alpine high-pressure fabrics below the Cyclades–Menderes thrust implies
c.
35 km of exhumation of the Cycladic blueschist prior to its Eocene emplacement on top of the Menderes nappes. Structure and geodynamic evolution of the Anatolide belt are in striking contrast to the neighbouring Aegean and contradict the model of a laterally continuous orogenic zone, in which the Anatolide microcontinent is interpreted as an eastern extension of the Adriatic plate.
Direct dating of authigenic K-feldspar overgrowths from the Kilombero Rift of Tanzania
Authors: HAGEN E. , KELLEY S. P. , DYPVIK H. , NILSEN O. , KJØLHAMAR B.
Published: June 2010

K-feldspars form important detrital and authigenic components in sediments but may be difficult to separate by conventional means for isotope analysis, particularly geochronology. UV lasers are being increasing applied to
in situ
analysis since they are strongly absorbed by clear minerals such as K-feldspar, and can achieve a spatial resolution of better than 20 μm for individual Ar/Ar analyses. Here we demonstrate separation of detrital K-feldspar with a mean age of 423±14 Ma and authigenic overgrowths with a mean age of 138±5 Ma in clastic sediments from the Msolwa Group of the Kilombero Rift of Tanzania. The young age obtained for authigenic K-feldspar overgrowth demonstrates that precipitation occurred more than 160 Ma after sedimentation, during the period of deepest burial and synchronous with the initial extensional phases of the intracontinental Anza and Sudan rifts, as well as the initial stages in the break-up and separation of South America and Africa.
Gravity evidence for diapiric ascent of the Northern Arran Granite
Authors: GOULTY N. R. , DOBSON A. J. , JONES G. D. , AL-KINDI S. A. , HOLLAND J. G.
Published: June 2010

Abstract:
The Northern Arran Granite has a sub-circular form in outcrop with a diameter of about 11 km. We have acquired six gravity profiles across the margin of the granite with an average station spacing of less than 250 m, two of which were extended to give an approximately diametric profile across the whole body. Simple modelling indicates that the granite ranges in thickness between 0.3 km and 1.2 km close to the margin, and that the base of the granite is approximately horizontal. Furthermore, the diametric profile shows no short-wavelength negative anomaly feature that could be associated with any abrupt increase in thickness of the granite. We concluded, therefore, that the granite probably has the form of a laccolith. More importantly, the shallow depth inferred for the base of the granite has a significant implication concerning its ascent mechanism. Intrusion of the granite led to the development of the Catacol synform in the Dalradian metasediments around its northwestern margin, and in 1992, England used structural analysis to demonstrate that the Dalradian rocks presently exposed at the margin were uplifted by 2–3 km during granite emplacement. Because gravity modelling shows that the granite is less than 1 km thick around its northwestern margin, the granite could not have uplifted beds from 2–3 km depth if it had been emplaced laterally following dyke ascent. Diapirism therefore appears to be the only ascent mechanism for the granite that is consistent both with its geometry and with the structures around its margin.
Nitric oxide and superoxide transport in a cross section of the rat outer medulla. I. Effects of low medullary oxygen tension
Authors: Edwards Aurélie , Layton Anita T.
Published: June 2010

To examine the impact of the complex radial organization of the rat outer medulla (OM) on the distribution of nitric oxide (NO), superoxide (O2−) and total peroxynitrite (ONOO), we developed a mathematical model that simulates the transport of those species in a cross section of the rat OM. To simulate the preferential interactions among tubules and vessels that arise from their relative radial positions in the OM, we adopted the region-based approach developed by Layton and Layton ( Am J Physiol Renal Physiol 289: F1346–F1366, 2005). In that approach, the structural organization of the OM is represented by means of four concentric regions centered on a vascular bundle. The model predicts the concentrations of NO, O2−, and ONOO in the tubular and vascular lumen, epithelial and endothelial cells, red blood cells (RBCs), and interstitial fluid. Model results suggest that the large gradients in Po2 from the core of the vascular bundle toward its periphery, which stem from the segregation of O2-supplying descending vasa recta (DVR) within the vascular bundles, in turn generate steep radial NO and O2− concentration gradients, since the synthesis of both solutes is O2 dependent. Without the rate-limiting effects of O2, NO concentration would be lowest in the vascular bundle core, that is, the region with the highest density of RBCs, which act as a sink for NO. Our results also suggest that, under basal conditions, the difference in NO concentrations between DVR that reach into the inner medulla and those that turn within the OM should lead to differences in vasodilation and preferentially increase blood flow to the inner medulla.
Regional differences in length change and electromyographic heterogeneity in sternohyoid muscle during infant mammalian swallowing
Authors: Konow Nicolai , Thexton Allan , Crompton A. W. , German Rebecca Z.
Published: June 2010

A complex sling of muscles moves and stabilizes the hyoid bone during many mammalian behaviors. One muscle in this sling, the sternohyoid, is recruited during food acquisition, processing, and swallowing, and also during nonfeeding behaviors. We used synchronous sonomicrometry and electromyography to investigate regional (intramuscular) changes in length and electromyographic (EMG) activity of the sternohyoid during swallowing in the infant pig. The simple straplike architecture of the sternohyoid led us to hypothesize that limited regional variation in length and muscle activity would be present. We found statistically significant regional differences in EMG activity, and, with respect to length dynamics, the sternohyoid did not behave homogeneously during swallowing. The midbelly region typically shortened while the anterior and posterior regions lengthened, although in a minority of swallows (12.5%) the midbelly lengthened simultaneously with the end-regions. Despite its nonpennate architecture and evolutionarily conservative innervation, the mammalian sternohyoid appears to contain previously unrecognized populations of regionally specialized motor units. It also displays differential contraction patterns, very similar to the sternohyoid of nonmammalian vertebrates.
Retinal Ganglion Cell Adaptation to Small Luminance Fluctuations
Authors: Freeman Daniel K. , Graña Gilberto , Passaglia Christopher L.
Published: June 2010

To accommodate the wide input range over which the visual system operates within the narrow output range of spiking neurons, the retina adjusts its sensitivity to the mean light level so that retinal ganglion cells can faithfully signal contrast, or relative deviations from the mean luminance. Given the large operating range of the visual system, the majority of work on luminance adaptation has involved logarithmic changes in light level. We report that luminance gain controls are recruited for remarkably small fluctuations in luminance as well. Using spike recordings from the rat optic tract, we show that ganglion cell responses to a brief flash of light are modulated in amplitude by local background fluctuations as little as 15% contrast. The time scale of the gain control is rapid (<125 ms), at least for on cells. The retinal locus of adaptation precedes the ganglion cell spike generator because response gain changes of on cells were uncorrelated with firing rate. The mechanism seems to reside within the inner retinal network and not in the photoreceptors, because the adaptation profiles of on and off cells differed markedly. The response gain changes follow Weber's law, suggesting that network mechanisms of luminance adaptation described in previous work modulates retinal ganglion cell sensitivity, not just when we move between different lighting environments, but also as our eyes scan a visual scene. Finally, we show that response amplitude is uniformly reduced for flashes on a modulated background that has spatial contrast, indicating that another gain control that integrates luminance signals nonlinearly over space operates within the receptive field center of rat ganglion cells.
Short-Term Bisphosphonate Therapy Could Ameliorate Osteonecrosis: A Complication in Childhood Hematologic Malignancies
Authors: Greggio N. A. , Pillon M. , Varotto E. , Zanin A. , Talenti E. , Palozzo A. C. , Calore E. , Messina C.
Published: June 2010

Osteonecrosis (ON) is a critical complication in the treatment of childhood leukemia and lymphoma. It particularly affects survivors of acute lymphoblastic leukemia and non-Hodgkin lymphoma reflecting the cumulative exposure to glucocorticosteroid therapy. ON is often multiarticular and bilateral, specially affecting weight-bearing joints. A conventional approach suggests a surgical intervention even if pharmacological options have also recently been investigated. We reported two cases of long time steroid-treated patients who underwent Bone Marrow Transplantation (BMT) for hematological disease. Both patients developed femoral head osteonecrosis (ON) that was diagnosed by magnetic resonance imaging (MRI) and the ON was also accompanied with pain and a limp. Despite of the conventional strategies of therapy, we successfully started a short-term treatment with bisphosphonates in order to decrease the pain and the risk of fracture.
Traumatic Pseudoaneurysm of the Middle Meningeal Artery Causing an Intracerebral Hemorrhage
Authors: Paiva Wellingson Silva , de Andrade Almir Ferreira , Amorim Robson Luis , Figueiredo Eberval Gadelha , Teixeira Manoel Jacobsen
Published: June 2010

Traumatic aneurysms comprise less than 1% of all intracranial aneurysms. Most of these aneurysms are actually false aneurysms, or pseudoaneurysms, which are caused by the rupture of entire vessel wall layers, with the wall of the aneurysm being formed by the surrounding cerebral structures. Traumatic pseudoaneurysms of the middle meningeal artery are also rare. Only four cases have been reported in the literature with intracerebral hematoma. In this paper, the authors report a case of a patient with a ruptured traumatic pseudoaneurysm of the MMA who presented with an intracerebral hematoma in the left temporal region immediately after trauma; the patient underwent endovascular treatment.
A Synthetic Approach of New Trans‐Substituted Hydroxylporphyrins
Authors: Daphnomili Dimitra , Grammatikopoulou Maria , Raptopoulou Catherine , Charalambidis George , Lazarides Theodore , Coutsolelos Athanasios G.
Published: June 2010

The synthesis of new trans A2B2‐substituted porphyrins bearing oxygenic substituent (methoxy, acetoxy, hydroxy) at the periphery of the ring are
described. All of the synthesized products were characterized by  1H‐N.M.R.,  13C‐N.M.R., and H.R.M.S. Electrochemical studies revealed two one‐electron oxidations and two reductions. In addition, the X‐ray structure of one methoxy‐derivative was determined.
A Case of Villoglandular Papillary Adenocarcinoma of the Uterine Cervix Diagnosed during Early Pregnancy Followed by Successful Term Delivery
Authors: Takai Noriyuki , Hayashita Chihiro , Nakamura Satoru , Narahara Hisashi , Matsumoto Hideo
Published: June 2010

Villoglandular papillary adenocarcinoma (VPA) is a very rare subtype of adenocarcinoma of the uterine cervix, but a well-recognized variant of cervical adenocarcinoma with a favorable prognosis and generally occurring in women of child-bearing age. Only five cases of VPA and pregnancy have been reported. Herein, we report a case of VPA diagnosed during early pregnancy and managed successfully with conservative measures; our patient delivered a healthy baby in full term. A successful pregnancy can be completed in patients with VPA without lymph-vascular invasion, when treated conservatively. This management is particularly desirable in young women to preserve reproductive capability.
Estrogen Receptor Signaling and Its Relationship to Cytokines in Systemic Lupus Erythematosus
Authors: Kassi E. , Moutsatsou P.
Published: June 2010

Dysregulation of cytokines is among the main abnormalities in Systemic Lupus Erythematosus (SLE). However, although, estrogens, which are known to be involved in lupus disease, influence cytokine production, the underlying molecular mechanisms remain poorly defined. Recent evidence demonstrates the presence of estrogen receptor in various cell types of the immune system, while divergent effects of estrogens on the cytokine regulation are thought to be implicated. In this paper, we provide an overview of the current knowledge as to how estrogen-induced modulation of cytokine production in SLE is mediated by the estrogen receptor while simultaneously clarifying various aspects of estrogen receptor signaling in this disease. The estrogen receptor subtypes, their structure, and the mode of action of estrogens by gene activation and via extranuclear effects are briefly presented. Results regarding the possible correlation between estrogen receptor gene polymorphisms and quantitative changes in the receptor protein to SLE pathology and cytokine production are reviewed.
The Outcomes of Gestational Diabetes Mellitus after a Telecare Approach Are Not Inferior to Traditional Outpatient Clinic Visits
Authors: Pérez-Ferre Natalia , Galindo Mercedes , Fernández M. Dolores , Velasco Victoria , Runkle Isabelle , de la Cruz M. José , Martín Rojas-Marcos Patricia , del Valle Laura , Calle-Pascual Alfonso L.
Published: June 2010

Objective. To evaluate the feasibility of a telemedicine system based on Internet and a short message service in pregnancy and its influence on delivery and neonatal outcomes of women with gestational diabetes mellitus (GDM).Methods. 100 women diagnosed of GDM were randomized into two parallel groups, a control group based on traditional face-to-face outpatient clinic visits and an intervention group, which was provided with a Telemedicine system for the transmission of capillary glucose data and short text messages with weekly professional feedback. 97 women completed the study (48/49, resp.).Main Outcomes Measured. The percentage of women achieving HbA1c values <5.8%, normal vaginal delivery and having a large for-gestational-age newborn were evaluated.Results. Despite a significant reduction in outpatient clinic visits in the experimental group, particularly in insulin-treated women (2.4 versus 4.6 hours per insulin-treated woman resp.;P<.001), no significant differences were found between the experimental and traditional groups regarding HbA1c levels (all women had HbA1c <5.8% during pregnancy), normal vaginal delivery (40.8% versus 54.2%, resp.;P>.05) and large-for-gestational-age newborns (6.1% versus 8.3%, resp.;P>.05).Conclusions. The system significantly reduces the need for outpatient clinic visits and achieves similar pregnancy, delivery, and newborn outcomes.
Identification of microRNAs Involved in the Host Response to Enterovirus 71 Infection by a Deep Sequencing Approach
Authors: Cui Lunbiao , Guo Xiling , Qi Yuhua , Qi Xian , Ge Yiyue , Shi Zhiyang , Wu Tao , Shan Jun , Shan Yunfeng , Zhu Zheng , Wang Hua
Published: June 2010

Role of microRNA (miRNA) has been highlighted in pathogen-host interactions recently. To identify cellular miRNAs involved in the host response to enterovirus 71 (EV71) infection, we performed a comprehensive miRNA profiling in EV71-infected Hep2 cells through deep sequencing. 64 miRNAs were found whose expression levels changed for more than 2-fold in response to EV71 infection. Gene ontology analysis revealed that many of these mRNAs play roles in neurological process, immune response, and cell death pathways, which are known to be associated with the extreme virulence of EV71. To our knowledge, this is the first study on host miRNAs expression alteration response to EV71 infection. Our findings supported the hypothesis that certain miRNAs might be essential in the host-pathogen interactions.
Production of Newcastle Disease Virus by Vero Cells Grown on Cytodex 1 Microcarriers in a 2-Litre Stirred Tank Bioreactor
Authors: Arifin Mohd Azmir , Mel Maizirwan , Abdul Karim Mohamed Ismail , Ideris Aini
Published: June 2010

The aim of this study is to prepare a model for the production of Newcastle disease virus (NDV) lentogenic F strain using cell culture in bioreactor for live attenuated vaccine preparation. In this study, firstly we investigated the growth of Vero cells in several culture media. The maximum cell number was yielded by culture of Vero cells in Dulbecco's Modified Eagle Medium (DMEM) which was1.93×106 cells/ml. Secondly Vero cells were grown in two-litre stirred tank bioreactor by using several commercial microcarriers. We achieved the maximum cell concentration about7.95×105 cells/ml when using Cytodex 1. Later we produced Newcastle Disease virus in stirred tank bioreactor based on the design developed using Taguchi L4 method. Results reveal that higher multiplicity of infection (MOI) and size of cell inoculums can yield higher virus titer. Finally, virus samples were purified using high-speed centrifugation based on3∗∗(3-1) Fractional Factorial Design. Statistical analysis showed that the maximum virus titer can be achieved at virus sample concentration of 58.45% (v/v), centrifugation speed of 13729 rpm, and centrifugation time of 4 hours. As a conclusion, high yield of virus titer could be achieved through optimization of cell culture in bioreactor and separation by high-speed centrifugation.
Crosstalk between Iron Metabolism and Erythropoiesis
Authors: Li Huihui , Ginzburg Yelena Z.
Published: June 2010

Iron metabolism and erythropoiesis are inextricably linked. The majority of iron extracted from circulation daily is used for hemoglobin synthesis. In the last 15 years, major advances have been made in understanding the pathways regulating iron metabolism. Hepcidin is a key regulator of iron absorption and recycling and is itself regulated by erythropoiesis. While several viable candidates have been proposed, elucidating the “erythroid regulator” of hepcidin continues to generate significant experimental activity in the field. Although the mechanism responsible for sensing iron demand for erythropoiesis is still incompletely understood, evaluating diseases in which disordered erythropoiesis and/or iron metabolism are showcased has resulted in a more robust appreciation of potential candidates coordinated erythroid iron demand with regulators of iron supply. We present data drawn from four different conditions—iron deficiency, congenital hypotransferrinemia, beta-thalassemia, and hereditary hemochromatosis—both in human and non-human models of disease, together suggesting that erythroid iron demand exerts a stronger influence on circulating iron supply than systemic iron stores. Greater understanding of the interplay between the key factors involved in the regulation of iron metabolism and erythropoiesis will help develop more effective therapies for disorders of iron overload, iron deficiency, and hemoglobin synthesis.
Role of Mental Disorders in Nosocomial Infections after Hip Fracture Treatment
Authors: Guerado Enrique , Cano Juan Ramon , Cruz Encarnacion , Benitez-Parejo Nicolás , Perea-Milla Emilio
Published: June 2010

The association between mental disorders (MDs) and iatrogenic complications after hip fracture surgery has been poorly studied. Among iatrogenic complications, nosocomial infections (NIs) are a major factor in hip fracture surgery. The aim of this paper was to determine whether patients with a MD and a hip fracture develop more NIs after hip surgery than patients with no MD. We studied 912 patients who underwent surgery for a hip fracture (223 patients with a MD who underwent surgery for a hip fracture and 689 control patients without a MD who also underwent surgery for a hip fracture) and followed them after surgery. Univariable and multivariable analyses were performed using simple and multiple logistic regression analysis (confidence interval, crude and adjusted odds ratios, andPvalue). We found that MDs, gender, and comorbidities were not associated with a higher risk of developing a NI after surgery for a hip fracture. Only age increases the risk of a NI.
Molecular and Clinical Aspects of Targeting the VEGF Pathway in Tumors
Authors: Korpanty Grzegorz , Sullivan Laura A. , Smyth Elizabeth , Carney Desmond N. , Brekken Rolf A.
Published: June 2010

Tumor angiogenesis is a complex process resulting from many signals from the tumor microenvironment. From preclinical animal models to clinical trials and practice, targeting tumors with antiangiogenic therapy remains an exciting area of study. Although many scientific advances have been achieved, leading to the development and clinical use of antiangiogenic drugs such as bevacizumab, sorafenib, and sunitinib, these therapies fall short of their anticipated benefits and leave many questions unanswered. Continued research into the complex signaling cascades that promote tumor angiogenesis may yield new targets or improve upon current therapies. In addition, the development of reliable tools to track tumor responses to antiangiogenic therapy will enable a better understanding of current therapeutic efficacy and may elucidate mechanisms to predict patient response to therapy.
Challenges in Treating Older Patients with Acute Myeloid Leukemia
Authors: Eleni Lagadinou D. , Nicholas Zoumbos C. , Alexandros Spyridonidis
Published: June 2010

Whereas in younger patients diagnosed with acute myeloid leukemia (AML) treatment is straightforward and the goal is cure, the optimal treatment decision for older adults remains highly controversial. Physicians need to determine whether palliation, “something” beyond palliation, intensive therapy, or an investigational therapy is the most appropriate treatment option. This requires understanding of the biology and risk profile of the AML, clinical judgment in evaluating the functional status of the patient, communication skills in understanding the patient's wishes and social background, and medical expertise in available therapies. The physician has to accurately inform the patient about (a) the unique biological considerations of his leukemia and his prognosis; (b) the risks and benefits of all available treatment options; (c) novel therapeutic approaches and how the patient can get access to these treatments. Last but not least, he has to recommend a treatment. This paper tries to discuss each of these issues.
Leigh's Disease: The Acute Clinical Course of a Two-Year-Old Child with Subacute Necrotizing Encephalomyelopathy
Authors: Zinka Bettina , Buettner Andreas , Graw Matthias
Published: June 2010

We report the untypical clinical course of a previously healthy two-year-old girl, who died suddenly and unexpectedly after an episode of vomiting. At forensic autopsy no other pathological findings could be diagnosed than multiple reddish, sunken areas in brain stem, mesencephalon, and pons. Histologically they presented as areas of spongiosis of the neuropil with prominent endothelial hyperplasia and vascular proliferation whereas nerve cells were well preserved. On the basis of the characteristic neuropathological findings in combination with the age of the child, we had to take into consideration that the child might have died from subacute necrotizing encephalomyelopathy (Leigh's Disease) despite the untypical, fulminant clinical course.
A Brief Outline of the History of the Pancreatic Anatomy
Authors: Tando Yusuke , Yanagimachi Miyuki , Matsuhashi Yuki , Nakamura Teruo , Kamisawa Terumi
Published: June 2010

In the middle of the 18th century, Kouan Kuriyama, a Japanese physician of the Choshu Domain, depicted the anatomy of the human pancreas in a report to his master, Toyo Yamawaki. This report is the first anatomical description of the pancreas in Japan. In the Mediterranean area, the pancreas was apparently first described about 2,000 years before his observation. Although there are quite a few reviews on the history of this complex organ, our brief essay offers a historical outline of the pancreas.
Embryology of the Biliary Tract
Authors: Ando Hisami
Published: June 2010

A hepatic diverticulum appears in the ventral wall of the primitive midgut early in the 4th week of intrauterine life in the development of the human embryo. This small diverticulum is the anlage for the development of the liver, extrahepatic biliary ducts, gallbladder, and ventral pancreas. By the 5th week, all elements of the biliary tree are recognizable. Marked elongation of the common duct occurs with plugging of the lumen by epithelial cells. Recanalization of the lumen of the common duct starts at the end of the 5th week and moves slowly distally. By the 6th week, the common duct and ventral pancreatic bud rotate 180° clockwise around the duodenum. Early in the 7th week, the bile and pancreatic ducts end in closed cavities of the duodenum. Between the early 8th and 12th week, hepatopancreatic ducts have both superior and inferior orifices. Of these two orifices, the inferior one is usually suppressed. The muscle of the sphincter of Oddi develops from a concentric ring of mesenchyme surrounding the preampullary portion of the bile and pancreatic ducts. At about the 10th week, the muscle of the sphincter of Oddi undergoes differentiation. In the 16th week, the muscularis propria extends from just outside the fenestra to the upper end of the ampulla. By the 28th week, the musculus proprius is differentiated almost to the distal end of the ampulla.
Function and Dysfunction of the Sphincter of Oddi
Authors: Tanaka Masao
Published: June 2010

In this review, the function of the sphincter of Oddi (SO) is detailed in terms of normal motility, neural and hormonal control of SO function, coordination between gallbladder and SO motility, and correlation of motility of the SO and the duodenum. In addition, SO function tests, such as the morphine Prostigmin test (Nardi test), perfusion manometry, microtransducer manometry, and cholescintigraphy, are explained. Subsequently, the pathophysiology, diagnosis, and treatment of SO dysfunction, including SO stenosis and dyskinesia, are described and discussed in detail. SO manometry and endoscopic sphincterotomy are effective to treat SO dysfunction, but symptoms of the patient must be severe enough to justify these invasive procedures for diagnosis and treatment.
Major Duodenal Papilla in Autoimmune Pancreatitis
Authors: Kim Myung-Hwan , Moon Sung-Hoon , Kamisawa Terumi
Published: June 2010

Autoimmune pancreatitis (AIP) is a distinctive form of chronic pancreatitis that can mimic pancreatobiliary malignancies. If AIP is properly diagnosed, it can be treated without laparotomy or pancreatic resection due to its dramatic response to steroid therapy. In addition to elevated serum IgG4 levels, IgG4 immunostaining of involved tissue is often used to support the diagnosis of AIP. The major duodenal papilla is a conduit between the duodenum and the pancreatobiliary system and occasionally reflects underlying pancreatobiliary disorders. Previous studies demonstrated that IgG4-positive lymphoplasmacytic infiltration was detected in the major duodenal papilla in connection to the pancreatic head in patients with AIP, and IgG4 immunostaining of biopsy specimens obtained from the major papilla could support a preoperative diagnosis of AIP. This review discusses macro- and microscopic findings of the major duodenal papilla of AIP patients, especially focusing on the diagnostic value of IgG4 immunostaining of duodenal papillary biopsy specimens.