bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-Tconditions during emplacement, and D2 regional metamorphism, of the Ben Vuirich Granite, Perthshire, Scotland
Authors: Ahmed-Said Y. , Tanner P. W. G. 
Published: July 2002

AbstractThe 590±2 Ma Ben Vuirich Granite was intruded into late Proterozoic Dalradian rocks prior to the Grampian orogeny, during which it was affected by upper amphibolite facies regional metamorphism. Spotted cordierite and andalusite (chiastolite) hornfelses at the granite margin were altered to kyanite-and garnet-bearing assemblages during regional metamorphism. From the inferred mineralogy of the hornfels, together with the normative Qz–Ab–Or values of the granite and the application of a simple cooling model, we conclude that the country rocks immediately adjacent to the granite were hornfelsed atT= ∼600°C andP≤ 2 kbar.The hornfelsed rocks were subsequently metamorphosed during the regional D2 event to form an equilibrium mineral assemblage of muscovite + biotite + garnet + plagioclase + quartz + kyanite (after chiastolite). Garnet which grew during this event shows unusual reversed chemical zoning, with Ca increasing systematically from core to rim as Fe, Mg and Mn decrease. A study of element partitioning between coexisting phases in equilibrium (including zoned garnets), and use of an internally consistent thermodynamic dataset, suggest that isothermal (T= 577±42°C) compression (fromP= 6.2±1.6 kbar to 9.0±1.9 kbar) occurred during crustal thickening. K-feldspar-plagioclase-quartz veinlets found in the hornfels close the granite contact are demonstrated to be of igneous origin.
A high-temperature hydrothermal origin for black dolomite matrix breccias in the Irish Zn-Pb orefield
Authors: Wilkinson J. J. , Earls G. 
Published: July 2002

AbstractWe make the first report of fluid inclusion data from a black dolomite matrix breccia from the Irish orefield which confirm a relatively high-temperature hydrothermal origin. Breccia matrix dolomite formed from NaCl-dominated fluids with temperatures primarily in the range 150–220°C and salinities of 13–20 wt.% NaCl equivalent, comparable with inferred ore-stage fluids at the Silvermines, Tynagh, Lisheen and Navan deposits. The spread in salinity is considered to be due to mixing of a moderate salinity (~12 wt.%), higher temperature fluid, probably derived from the Lower Palaeozoic metasedimentary basement, with a low temperature brine. Non-stoichiometric, black dolomites are therefore considered to be a product of relatively high-temperature hydrothermal processes involving the principal orefluid in Ireland, and thus their occurrence is believed to be a prime exploration indicator.Earlier, coarse white dolomite, texturally similar to regional dolomite cements commonly observed in the Irish Midlands, precipitated from fluids in the temperature range 140–200°C and salinities of 10.3–13.5 wt.% NaCl equivalent. This is comparable with the higher temperature, moderate salinity end-member inferred for the black dolomite. These data call into question a uniquely low-temperature burial origin for coarse white dolomite cements in Ireland. Paragenetically late low-Mg calcites were formed as a result of an influx of relatively low salinity fluids.
An ab initio study of the relative stabilities and equations of state of FeS polymorphs
Authors: Martin P. , Price G. D. , Vočadlo L. 
Published: July 2002

AbstractAn investigation into the relative stabilities and equations of state of stoichiometric FeS was conducted using first-principles pseudopotential calculations. These calculations were based on density functional theory and performed using ultrasoft Vanderbilt pseudopotentials within the generalized gradient approximation. We have identified four stable polymorphs of FeS along the 0 K isotherm as a function of pressure: troilite, an orthorhombic MnP-type structure, a monoclinic structure, and a CsCl-type structure. The calculated internal energy as a function of volume for each polymorph was fitted to 4th order logarithmic and 3rd order Birch-Murnaghan equations of state, yielding values for the bulk modulus, K, and its first and second derivatives with respect to pressure, K′ and K″. These equations of state may be used to characterize models of planetary cores.
REE fractionation by accessory minerals in epidote-bearing metaluminous granitoids from the Sierras Pampeanas, Argentina
Authors: Dahlquist J. A. 
Published: July 2002

AbstractA study of the distribution of REE in epidote-bearing metaluminous granitoids from Sierra de Chepes, Sierras Pampeanas, Argentina, reveals that a large proportion of the REE reside in the accessory minerals (allanite, epidote, titanite, apatite and zircon), and therefore these minerals control the behaviour of REE in granitic magmas. Well-developed chemical zonation in titanite indicates that the REE content decreases in the melt during crystallization of this mineral. The textural and chemical characteristics of euhedral epidote suggest a magmatic origin, and in that case it may have played an important role in the fractionation of the REE. The amount of silica and any other geochemical parameter indicative of fractionation progress in the dominant granodioritic-tonalitic facies (gtf) do not correlate with observed variations in the REE patterns. When many accessory minerals are involved, as in the gtf, the differentiated melts (e.g. aplites) are REE poor. Thus, the presence/absence of accessory minerals in granitoids can be indicative of the generation of differentiated melt enriched or poor in REE and other trace elements. This may have an economic significance, as it may allow us to predict the probable geochemistry of the differentiated melts (i.e. those that tend to develop mineralization) from the textural analysis of the ‘regional’ granitic rock.Finally, the type and abundance of accessory minerals in the granitic suite can also help us to define the geotectonic environment where magmas were generated.
Encouraging the extrusion of deep-crustal rocks in collisional zones
Authors: Hynes A. 
Published: July 2002

AbstractMost unroofing mechanisms invoked for the exhumation of blueschist-plus-eclogite terranes, including corner-flow and extensional collapse of the orogenic wedge, predict steep unroofing paths for the deeply-buried rocks and are applicable only to unroofing from depths within the crust. Many high-P and ultrahigh-P rocks of continental affinity are derived from greater depths than this. Their lack of warming during unroofing, together with indications that they may rest directly on less deeply buried equivalents, are suggestive of shallow unroofing paths similar to those for the subduction-channel model. They are interpreted to have been emplaced by the upward extrusion of coherent slices of continental crust, bounded below by thrust faults and above by normal faults, with unroofing paths essentially reversing the original burial paths.Where continental crust has been subducted into the mantle, upward extrusion is probably driven largely by buoyancy forces, although examples of upward extrusion without subduction into the mantle indicate that buoyancy forces may not be essential. Two features in addition to buoyancy may promote upward extrusion. Slab breakoff may reduce the pull from the descending slab, and subduction-zone geometry may change as a continental margin is dragged into the subduction zone. Both features may promote the extrusion of continental crust at precisely the time at which it has been partially subducted.A close spatial relationship between a lateral ramp and a lobate zone of extruded high-P rocks in the Mesoproterozoic Grenvillian orogen indicates that lateral ramps may be important in localizing extrusion. Lateral ramps disturb the two-dimensional flow, with channelling of material into the region of the lateral ramp as it is extruded. Many exhumed ultrahigh-P terrains are associated with jogs in the trends of orogenic fronts that may reflect the presence of lateral ramps at depth. Ultrahigh-P rocks may be expected to be concentrated at such jogs, and may record the channelling in their deformation history.
Rates of erosion and their implications for exhumation
Authors: Burbank D. W. 
Published: July 2002

AbstractAt time-scales of 102to 105years, erosion by rivers, landslides and glaciers can exceed 5 mm/y. Sustained denudation at these rates is sufficient to account for many of the rapid rates of unloading or cooling that are revealed by geobarometric or thermochronologic studies. Because feedbacks exist among many surface processes, determinations of erosion rates on a few geomorphic processes can be adequate to estimate mean rates across an entire landscape. Rates of fluvial and glacial incision exert a dominant control on landscape lowering, because these rates set the local base level and modulate the flux from adjacent hillslopes. When rates of deformation are sufficiently rapid and sustained, a collisional orogen approaches a dynamic equilibrium or topographic steady state. Due to variations in erosion rates as a function of Late Cenozoic climate changes, such a steady state should be defined at time-scales longer than one climate cycle. During dynamic equilibrium, the geomorphic system displays a predictable configuration of interacting rivers, hillslopes and glaciated process zones. A dynamic equilibrium appears to prevail near Nanga Parbat, Pakistan, and the Southern Alps of New Zealand, where spatial variations in geomorphic erosion rates mimic variations in bedrock cooling rates at time-scales of 106y.
The correlation between lithium and magnesium in trioctahedral micas: Improved
equations for Li2O estimation from MgO data
Authors: Tischendorf G. , Förster H.-J. , Gottesmann B. 
Published: July 2002

Abstract
A major disadvantage of the electron microprobe is its inability to determine
Li, which may make up an essential component in micaceous minerals. Correct
classification of micas and proper calculation of their formulae require
alternative methods. One of these is the indirect estimation of the lithium
concentration by empirical approaches based on element correlations. Relationships
between Li2O and SiO2 have long been
used for this purpose; however, they are valid only for a limited range of mica
compositions (i.e. Li-rich, Mg-poor varieties).
In this paper we report the results from a renewed study of the correlation
between Li2O and MgO contents in trioctahedral micas. It is
demonstrated that the relations between both oxides are strongly dependent upon
the geological environment in which the mica was formed. It is necessary to
distinguish a ‘normal group’, which comprises micas from ‘common’ S- and I-type
magmatic rocks and most metamorphic rocks , a ‘low Li-Mg group’, to which belong
Fe-rich micas from non-alkaline rocks of A-type affinity, and a ‘high Li-Mg group’
which includes micas from either peraluminous or peralkaline igneous rocks and
Mg-enriched wall-rocks. These wall rocks supplied additional magnesium to the
mica-forming environment. We offer empirical expressions relating
Li2O and MgO contents for these three types which, in many
cases, allow a sufficiently good estimation of the lithium content in
trioctahedral micas of widely varying compositions.
Mimicry between neurokinin-1 and fibronectin may explain the transport and stability of increased substance P immunoreactivity in patients with bone marrow fibrosis
Authors: Rameshwar Pranela , Joshi Deval D. , Yadav Prem , Qian Jing , Gascon Pedro , Chang Victor T. , Anjaria Devashish , Harrison Jonathan S. , Song Xiaosong 
Published: July 2002

AbstractBone marrow (BM) fibrosis may occur in myeloproliferative diseases, lymphoma, myelodysplastic syndrome, myeloma, and infectious diseases. In this study, the role of substance P (SP), a peptide with pleiotropic functions, was examined. Some of its functions—angiogenesis, fibroblast proliferation, and stimulation of BM progenitors—are amenable to inducing BM fibrosis. Indeed, a significant increase was found in SP-immunoreactivity (SP-IR) in the sera of patients with BM fibrosis (n = 44) compared with the sera of patients with hematologic disorders and no histologic evidence of fibrosis (n = 46) (140 ±12 vs 18 ±3; P &lt; .01). Immunoprecipitation of sera SP indicated that this peptide exists in the form of a complex with other molecule(s). It was, therefore, hypothesized that SP might be complexed with NK-1, its natural receptor, or with a molecule homologous to NK-1. To address this, 3 cDNA libraries were screened that were constructed from pooled BM stroma or mononuclear cells with an NK-1 cDNA probe. A partial clone (clone 1) was retrieved that was 97% homologous to the ED-A region of fibronectin (FN). Furthermore, sequence analyses indicated that clone 1 shared significant homology with exon 5 of NK-1. Immunoprecipitation and Western blot analysis indicated co-migration of SP and FN in 27 of 31 patients with BM fibrosis. Computer-assisted molecular modeling suggested that similar secondary structural features between FN and NK-1 and the relative electrostatic charge might explain a complex formed between FN (negative) and SP (positive). This study suggests that SP may be implicated in the pathophysiology of myelofibrosis, though its role would have to be substantiated in future research.
Allogeneic chimerism with low-dose irradiation, antigen presensitization, and costimulator blockade in H-2 mismatched mice
Authors: Quesenberry Peter J. , Zhong Suju , Wang Han , Stewart Marc 
Published: July 2002

AbstractWe have previously shown that the keys to high-level nontoxic chimerism in syngeneic models are stem cell toxic, nonmyelotoxic host treatment as provided by 100-cGy whole-body irradiation and relatively high levels of marrow stem cells. This approach was unsuccessful in H-2 mismatched B6.SJL to BALB/c marrow transplants, but with tolerization, stable multilineage chimerism was obtained. Ten million B6.SJL spleen cells were infused intravenously into BALB/c hosts on day −10 and (MR-1) anti-CD40 ligand monoclonal antibody (mAb) injected intraperitoneally at varying levels on days −10, −7, −3, 0, and +3 and the BALB/c mice irradiated (100 cGy) and infused with 40 million B6.SJL/H-2 mismatched marrow cells on day 0. Stable multilineage chimerism at levels between 30% to 40% was achieved in the great majority of mice at 1.6 mg anti-CD40 ligand mAb per injection out to 64 weeks after transplantation, without graft-versus-host disease. The transplanted mice were also tolerant of donor B6.SJL, but not third-party CBA/J skin grafts at 8 to 9 and 39 to 43 weeks after marrow transplantation. These data provide a unique model for obtaining stable partial chimerism in H-2 mismatched mice, which can be applied to various clinical diseases of man such as sickle cell anemia, thalassemia, and autoimmune disorders.
Oncostatin M promotes biphasic tissue factor expression in smooth muscle cells: evidence for Erk-1/2 activation
Authors: Nishibe Toshiya , Parry Graham , Ishida Atsushi , Aziz Salim , Murray Jacqueline , Patel Yatin , Rahman Salman , Strand Kurt , Saito Keiko , Saito Yuji , Hammond William P. , Savidge Geoffrey F. , Mackman Nigel , Wijelath Errol S. 
Published: July 2002

AbstractTissue factor (TF), a transmembrane glycoprotein, initiates the extrinsic coagulation cascade. TF is known to play a major role in mediating thrombosis and thrombotic episodes associated with the progression of atherosclerosis. Macrophages at inflammatory sites, such as atherosclerotic lesions, release numerous cytokines that are capable of modulating TF expression. This study examined the role of oncostatin M (OSM), a macrophage/ T-lymphocyte–restricted cytokine, in the expression of TF in vascular smooth muscle cells (SMCs). It is reported here that OSM stimulated a biphasic and sustained pattern of TF messenger RNA (mRNA). The effect of OSM on TF mRNA expression was regulated at the transcriptional level as determined by nuclear run-offs and transient transfection of a TF promoter-reporter gene construct. OSM-induced TF expression was regulated primarily by the transcription factor NF-κB. Activation of NF-κB by OSM did not require IκB-α degradation. Inhibition of MEK activity by U0126 prevented OSM-induced TF expression by suppressing NF-κB DNA binding activity as determined by gel-shift analysis. Further, inhibition of Erk-1/2 protein by antisense treatment resulted in suppression of TF mRNA expression, indicating a role for Erk-1/2 in modulating NF-κB DNA binding activity. These studies suggest that the induced expression of TF by OSM is primarily through the activation of NF-κB and that activation of NF-κB is regulated in part by the MEK/Erk-1/2 signal transduction pathway. This study indicates that OSM may play a key role in promoting TF expression in SMCs within atherosclerotic lesions.
Lipoprotein (a) up-regulates the expression of the plasminogen activator inhibitor 2 in human blood monocytes
Authors: Buechler Christa , Ullrich Heidrun , Ritter Mirko , Porsch-Oezcueruemez Mustafa , Lackner Karl J. , Barlage Stefan , Friedrich Sven Olaf , Kostner Gert M. , Schmitz Gerd 
Published: July 2002

AbstractElevated plasma lipoprotein (a) (Lp[a]) and cardiac events show a modest but significant association in various clinical studies. However, the influence of high Lp(a) on the gene expression in blood monocytes as a major cell involved in atherogenesis is poorly described. To identify genes influenced by elevated serum Lp(a), the gene expression was analyzed on a complementary DNA microarray comparing monocytes from a patient with isolated Lp(a) hyperlipidemia and coronary heart disease with monocytes from a healthy blood donor with low Lp(a). By using this approach, numerous genes were found differentially expressed in patient-versus-control monocytes. Verification of these candidates by Northern blot analysis or semiquantitative polymerase chain reaction in monocytes from additional patients with Lp(a) hyperlipidemia and healthy blood donors with elevated Lp(a) confirmed a significant induction of plasminogen activator inhibitor type 2 (PAI-2) messenger RNA (mRNA) in monocytes from male, but not from female, individuals with high Lp(a), indicating that this observation is gender specific. This led also to increased intracellular and secreted PAI-2 protein in monocytes from male probands with Lp(a) hyperlipidemia. Plasminogen activator inhibitor type 1 (PAI-1) mRNA was found suppressed only in the patients′ monocytes and not in healthy probands with high Lp(a) levels. Purified Lp(a) induced PAI-2 mRNA and protein and reduced PAI-1 expression in monocytes isolated from various controls. The finding that PAI-2 is elevated in monocytes from male patients with isolated Lp(a) hyperlipidemia and male healthy probands with high Lp(a) and that purified Lp(a) up-regulates PAI-2 in control monocytes in vitro indicate a direct, but gender-specific, effect of Lp(a) for the induction of PAI-2 expression.
Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia
Authors: Migliazza Anna , Bosch Francesc , Komatsu Hirokazu , Cayanis Eftihia , Martinotti Stefano , Toniato Elena , Guccione Ernesto , Qu Xiaoyan , Chien Minchen , Murty V. V. V. , Gaidano Gianluca , Inghirami Giorgio , Zhang Peisen , Fischer Stuart , Kalachikov Sergey M. , Russo James , Edelman Isidore , Efstratiadis Argiris , Dalla-Favera Riccardo 
Published: July 2002

Abstract
Deletions of the 13q14 chromosome region are associated with B-cell chronic lymphocytic leukemia (B-CLL) and several other types of cancer, suggesting the presence of a tumor suppressor gene. In previous studies the minimal region of deletion (MDR) was mapped to a less than 300-kilobase (kb) interval bordered by the markers 173a12-82 and 138G4/1.3R. For the identification of the putative tumor suppressor gene, the entire MDR (approximately 347 kb) has been sequenced, and transcribed regions have been identified by exon trapping, EST-based full-length complementary DNA cloning, database homology searches, and computer-assisted gene prediction analyses. The MDR contains 2 pseudogenes and 3 transcribed genes: CAR, encoding a putative RING-finger containing protein; 1B4/Leu2, generating noncoding transcripts; and EST70/Leu1, probably representing another noncoding gene (longest open reading frame of 78 codons). These genes have been sequenced in 20 B-CLL cases with 13q14 hemizygous deletion, and no mutations were found. Moreover, no somatic variants were found in the entire MDR analyzed for nucleotide substitutions by a combination of direct sequencing and fluorescence-assisted mismatch analysis in 5 B-CLL cases displaying 13q14-monoallelic deletion. The nondeleted allele of theCAR and EST70/Leu1 genes was expressed in B-CLL specimens, including those with monoallelic loss, whereas no expression of 1B4/Leu2 was detectable in B-CLL, regardless of the 13q14 status. These results indicate that allelic loss and mutation of a gene within the MDR is an unlikely pathogenetic mechanism for B-CLL. However, haplo-insufficiency of one of the identified genes may contribute to tumorigenesis.
The C-class chemokine lymphotactin costimulates the apoptosis of human CD4+ T cells
Authors: Cerdan Chantal , Devilard Elisabeth , Xerri Luc , Olive Daniel 
Published: July 2002

AbstractClonal expansion of activated T cells is controlled by homeostatic mechanisms leading to cell death of a large proportion of the cells. The CD3/TcR pathway induces cell death, mostly when triggered in the absence of costimulatory signal. The unique T cell–specific chemokine of the C class, lymphotactin (Lptn), has recently been shown to inhibit the production of Th1-type lymphokines in human CD4+ T cells. The present study shows the ability of Lptn to costimulate the death of CD4+ T lymphocytes triggered through CD3/TCR. The Lptn-mediated increased cell death exhibited characteristic features of apoptosis, as mainly determined by DNA fragmentation and exposure of an apoptotic-specific mitochondrial antigen. This apoptosis was dependent on Fas/FasL signaling, was not rescued by addition of interleukin 2, and proceeded with a predominant processing of both initiator procaspase-9 and effector procaspase-7. These caspase activities were further evidenced by specific cleavage of poly(ADP-ribose) polymerase (PARP) and CD3/TCR ζ-chain, but not DNA fragmentation factor (DFF45). This study demonstrates that the functional repertoire of Lptn in the regulation of human CD4+ T-lymphocyte activation includes the ability to costimulate apoptosis.