bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minor elements in olivine from spinel lherzolite xenoliths: implications for thermobarometry
Authors: O'Reilly Suzanne Y. , Chen D. , Griffin W. L. , Ryan C. G. 
Published: December 2006

AbstractThe proton microprobe has been used to determine contents of Ca, Ti, Ni, Mn and Zn in the olivine of 54 spinel lherzolite xenoliths from Australian and Chinese basalts. These data are compared with proton-probe data for Ni, Mn and Zn in the olivine of 180 garnet peridotite xenoliths from African and Siberian kimberlites. Fe, Mn, Ni and Zn contents are well-correlated; because the spinel lherzolite olivines have higher mean Fe contents than garnet peridotite olivines (average Fo89.6vs. Fo90–92) they also have lower Ni and higher Mn contents. Zn and Fe are well-correlated in garnet peridotite olivine, but in spinel peridotites this relationship is perturbed by partitioning of Zn into spinel. None of these elements shows significant correlation with temperature. Consistent differences in trace-element contents of olivines in the two suites is interpreted as reflecting the greater degree of depletion of Archean garnet peridotites as compared to Phanerozoic spinel lherzolites. Ca and Ti contents of spinel-peridotite olivine are well correlated with one another, and with temperature as determined by several types of geothermometer. However, Ca contents are poorly correlated with pressure as determined by the Ca-in-olivine barometer of Köhler and Brey (1990). This reflects the strong T-dependence of this barometer: the uncertainty in pressure (calculated by this method) which is produced by the ±50°C uncertainty expected of any geothermometer is ca ± 8 kbar, corresponding to the entire width of the spinel-lherzolite field at 900–1200°C.
Techniques and methodology used in a mineralogical and osmium isotope study of platinum group minerals from alluvial deposits in Colombia, California, Oregon and Alaska
Authors: Lyon I. C. , Tamana H. , Vaughan D. J. , Criddle A. J. , Saxton J. M. , van Lierde P. 
Published: December 2006

AbstractPlatinum-group minerals (PGM) from placer deposits in Colombia, California, Oregon and Alaska were investigated with the electron microprobe, proton microprobe (μ-PIXE) and ion probe to analyse their major and trace element contents and 187Os/186Os isotopic ratios. Most of the grains in the samples investigated proved to be essentially homogeneous alloys of Pt-Fe and Os-Ir-Ru although a few of them contained inclusions of other PGM such as cooperite and laurite. Detailed analyses were undertaken on the Os-Ir-Ru alloy phases.The 187Os/186Os isotope ratios fell into a range from 1.005 to 1.156 and are consistent with data published on PGM from other placer deposits from these regions. The ratios, together with the trace element data (and in particular the low rhenium content) determined by ion probe and μ-PIXE, indicate that crustal osmium was not incorporated in the grains and that no significant evolution of the 187Os/186Os ratios occurred during their history. These data, along with mineralogical and textural evidence, are consistent with a mantle origin for the grains through ultramafic intrusions, although the data do not entirely rule out alternative interpretations.
Digital analysis of X-ray films
Authors: Palmer David C. 
Published: December 2006

AbstractHigh-resolution intensity profiles can be generated from X-ray diffraction films using a desk-top scanner and computer image analysis. The resulting intensity profiles have spatial resolutions equal to, or exceeding that of modern powder diffractometers — at a fraction of the cost. This technique provides an economical way of preserving the information stored in libraries of old (and deteriorating) powder diffraction films. The same technique can also be extended to permit quantitative analysis of single-crystal diffraction films.
An EXAFS study of the local structural environments of Fe, Co, Zn and Mg in natural and synthetic staurolites
Authors: Henderson C. M. B. , Charnock J. M. , Cressey G. , Griffen D. T. 
Published: December 2006

AbstractX-ray absorption spectroscopy (XAS) has been used to study the local structures of Fe, Co, Zn, and Mg in synthetic and natural staurolites. Results for the near-edge features (XANES) and refined EXAFS were used to deduce the crystallographic site(s) occupied for each element. The least squares refined, mean first shell metal-O bond lengths, coordination numbers, and Debye-Waller factors are in the ranges: Fe 1.97–1.99 Å, 3.5–4.1, 0.013–0.023 Å2; Co 1.97–1.98 Å, 3.5–3.9, 0.009–0.014 Å2; Zn 1.95–1.96 Å, 3.7–3.8, 0.008–0.009 Å2; and Mn 1.99 Å, 3.8, 0.012 Å2. No significant differences were found which depended on element concentration or whether the sampes are synthetic or natural. The refined bond length for Mg in end-member Mg-staurolite is 2.00 Å but EXAFS data did not allow refinement to give reliable coordination number and Debye-Waller factor estimates. The EXAFS data, together with staurolite and model compound XANES features, suggest that > about 90% of Fe, Co, Zn and Mn are concentrated in the tetrahedral T2 site, while in Mg-staurolite > about 75% of the total Mg is in T2 with the remainder in octahedral sites. In natural staurolite from Pizzo Forno (PF2), a greater proportion of Mg appears to be in octahedral coordination.
A numerical approach for the formation of chlorite and sulphide-bearing greisen: a study based on the Navalcubilla system (Spanish Central System)
Authors: Tornos Fernando 
Published: December 2006

AbstractThe formation of sulphide and cassiterite-bearing chlorite-rich greisens in the Navalcubilla granite has been modelled theoretically. Numerical simulation on the reaction of a hydrothermal fluid with a granitic rock predicts assemblages very similar to those found in nature, with progressive formation of muscovite, quartz, chlorite, microcline and plagioclase zones. The hydrothermal alteration of the rock produces a neutralization of the inflowing acid fluid, a drop in the fS2 and, to a lesser degree, an increment in fO2. During hydrothermal alteration, fS2 and fO2 change abruptly between metasomatic zones, but chlorite seems to control their major changes. Scheelite and cassiterite are concentrated in the internal zones, while sulphides are related to the more external zones. Fluid-rock reactions seem to be very effective for precipitating cassiterite and scheelite, even from very Sn and W-poor fluids. Appreciable amounts of sulphides are only expected in systems with high concentrations of base metals. Boiling and simple cooling of the fluids acidifies and oxidizes them but chemical changes are not strong enough to induce significant precipitation of ore minerals, at least when the temperature changes are small. Continued circulation of fluids along fractures with previously precipitated quartz + wolframite produces replacement of wolframite by scheelite and sulphides.
Jarosite formation in weathered siliceous chalk in Fontevrault abbey, Loire Valley, France
Authors: Bauer Andreas , Velde Bruce 
Published: December 2006

AbstractJarosite, a hydrous potassium iron sulphate mineral, has been found as the product of weathering in a silicic chalk building stone of a 13th century abbey at Fontevrault (Maine-et-Loire, France). Destabilization of pyrite and glauconite dispersed in the calcareous stone results in the formation of jarosite. The alteration process is probably of very local origin, within the zone in the building stone at its surface where oxidation occurs during wetting and drying on a cyclical basis. The problem of the incompatibility of highly acidic solutions needed to stabilise jarosite (2.5 < pH) within the highly porous, calcareous silicate rock is not explained at present.
Vav proteins control MyD88-dependent oxidative burst
Authors: Miletic Ana V. , Graham Daniel B. , Montgrain Vivianne , Fujikawa Keiko , Kloeppel Tracie , Brim Karry , Weaver Brian , Schreiber Robert , Xavier Ramnik , Swat Wojciech 
Published: December 2006

AbstractThe importance of reactive oxygen intermediate (ROI) production in antimicrobial responses is demonstrated in human patients who suffer from chronic granulomatous disease (CGD) due to defective NADPH oxidase function. Exactly how bacterial products activating Toll-like receptors (TLRs) induce oxidative burst is unknown. Here, we identify the Vav family of Rho guanine nucleotide exchange factors (GEFs) as critical mediators of LPS-induced MyD88-dependent activation of Rac2, NADPH oxidase, and ROI production using mice deficient in Vav1, Vav2, and Vav3. Vav proteins are also required for p38 MAPK activation and for normal regulation of proinflammatory cytokine production, but not for other MyD88-controlled effector pathways such as those involving JNK, COX2, or iNOS and the production of reactive nitrogen intermediates (RNIs). Thus, our data indicate that Vav specifically transduces a subset of signals emanating from MyD88.
Endothelial Lu/BCAM glycoproteins are novel ligands for red blood cell α4β1integrin: role in adhesion of sickle red blood cells to endothelial cells
Authors: El Nemer Wassim , Wautier Marie-Paule , Rahuel Cécile , Gane Pierre , Hermand Patricia , Galactéros Frédéric , Wautier Jean-Luc , Cartron Jean-Pierre , Colin Yves , Le Van Kim Caroline 
Published: December 2006

AbstractThe Lutheran (Lu) blood group and basal cell adhesion molecule (BCAM) antigens are both carried by 2 glycoprotein isoforms of the immunoglobulin superfamily representing receptors for the laminin α5 chain. In addition to red blood cells, Lu/BCAM proteins are highly expressed in endothelial cells. Abnormal adhesion of red blood cells to the endothelium could potentially contribute to the vaso-occlusive episodes in sickle cell disease. Considering the presence of integrin consensus-binding sites in Lu/BCAM proteins, we investigated their potential interaction with integrin α4β1, the unique integrin expressed on immature circulating sickle red cells. Using cell adhesion assays under static and flow conditions, we demonstrated that integrin α4β1 expressed on transfected cells bound to chimeric Lu-Fc protein. We showed that epinephrine-stimulated sickle cells, but not control red cells, adhered to Lu-Fc via integrin α4β1 under flow conditions. Antibody-mediated activation of integrin α4β1 induced adhesion of sickle red cells to primary human umbilical vein endothelial cells; this adhesion was inhibited by soluble Lu-Fc and vascular cell adhesion molecule-1 (VCAM-1)–Fc proteins. This novel interaction between integrin α4β1 in sickle red cells and endothelial Lu/BCAM proteins could participate in sickle cell adhesion to endothelium and potentially play a role in vaso-occlusive episodes.
Hemolysis in sickle cell mice causes pulmonary hypertension due to global impairment in nitric oxide bioavailability
Authors: Hsu Lewis L. , Champion Hunter C. , Campbell-Lee Sally A. , Bivalacqua Trinity J. , Manci Elizabeth A. , Diwan Bhalchandra A. , Schimel Daniel M. , Cochard Audrey E. , Wang Xunde , Schechter Alan N. , Noguchi Constance T. , Gladwin Mark T. 
Published: December 2006

AbstractPulmonary hypertension is a highly prevalent complication of sickle cell disease and is a strong risk factor for early mortality. However, the pathophysiologic mechanisms leading to pulmonary vasculopathy remain unclear. Transgenic mice provide opportunities for mechanistic studies of vascular pathophysiology in an animal model. By microcardiac catheterization, all mice expressing exclusively human sickle hemoglobin had pulmonary hypertension, profound pulmonary and systemic endothelial dysfunction, and vascular instability characterized by diminished responses to authentic nitric oxide (NO), NO donors, and endothelium-dependent vasodilators and enhanced responses to vasoconstrictors. However, endothelium-independent vasodilation in sickle mice was normal. Mechanisms of vasculopathy in sickle mice involve global dysregulation of the NO axis: impaired constitutive nitric oxide synthase activity (NOS) with loss of endothelial NOS (eNOS) dimerization, increased NO scavenging by plasma hemoglobin and superoxide, increased arginase activity, and depleted intravascular nitrite reserves. Light microscopy and computed tomography revealed no plexogenic arterial remodeling or thrombi/emboli. Transplanting sickle marrow into wild-type mice conferred the same phenotype, and similar pathobiology was observed in a nonsickle mouse model of acute alloimmune hemolysis. Although the time course is shorter than typical pulmonary hypertension in human sickle cell disease, these results demonstrate that hemolytic anemia is sufficient to produce endothelial dysfunction and global dysregulation of NO.
Thromboxane receptor blockade improves the antiatherogenic effect of thromboxane A2 suppression in LDLR KO mice
Authors: Cyrus Tillmann , Yao Yuemang , Ding Tao , Dogné Jean Michel , Praticò Domenico 
Published: December 2006

Abstract
Suppression of thromboxane (Tx) A2 biosynthesis retards atherogenesis. In this setting, the coincidental presence of nonconventional ligands for the TxA2 receptor (TP), such as isoprostanes, could still induce a proatherogenic vascular phenotype. However, no data are available on the effect of combining suppression of TxA2 formation with blockade of TP in atherogenesis. To this end, we tested the effect of a selective COX-1 inhibitor, SC560, a TP antagonist, BM-573, or a combination of both in low-density lipoprotein receptor-deficient mice on a high-fat diet. None of the treatments affected body weight or plasma cholesterol or triglycerides levels. Although SC-560 suppressed TxA2 biosynthesis, BM-573 reduced its levels by 35%; in contrast, the 2 drugs, alone or in combination, did not significantly affect prostacyclin levels. At the end of the study, SC560 and BM-573 reduced atherogenesis; however, a further significant decrease was observed in mice receiving both drugs. This effect was associated with a further significant reduction of vascular inflammation, a decrease in macrophages, and an increase in the content of collagen and smooth muscle cells of the atherosclerotic lesions. These results show for the first time that the addition of a TP antagonist increases the antiatherogenic effect of COX-1–dependent TxA2 suppression.
Penumbra encodes a novel tetraspanin that is highly expressed in erythroid progenitors and promotes effective erythropoiesis
Authors: Heikens Marc J. , Cao Thai M. , Morita Chikako , DeHart Sarah L. , Tsai Schickwann 
Published: December 2006

AbstractIn a search for new genes involved in the regulation of erythropoiesis, we identified murine Penumbra cDNA from a multipotent hematopoietic cell line based on its predominant expression in erythroblasts. Subsequently, we identified the human PENUMBRA from a bone marrow cDNA library. Penumbra is a new member of the tetraspanin superfamily of membrane proteins, many of which are thought to function as organizers of supramolecular signaling complexes. Human and murine Penumbras contain 283 amino acids and are 97% identical. The human PENUMBRA gene is mapped to chromosome 7q32, a hot spot for deletions in myelodysplastic syndromes and acute myelogenous leukemias. Penumbra is targeted to the cell surface and forms disulfide-bonded homodimers. To study the effects of Penumbra deletions, we created a knockout mouse model by gene targeting. Penumbra−/− mice develop massive splenomegaly, basophilic macrocytic red blood cells, and anemia as they age. A multipotent hematopoietic cell line, EMX, was established from the bone marrow of a Penumbra−/− mouse. EMX exhibits ineffective erythropoiesis in the presence of erythropoietin, a defect that is reversed by reexpression of Penumbra. These findings indicate that Penumbra has a positive function in erythropoiesis and its deletion or mutation may result in anemia.
MafB negatively regulates RANKL-mediated osteoclast differentiation
Authors: Kim Kabsun , Kim Jung Ha , Lee Junwon , Jin Hye Mi , Kook Hyun , Kim Kyung Keun , Lee Soo Young , Kim Nacksung 
Published: December 2006

AbstractReceptor activator of nuclear factor κB ligand (RANKL) induces osteoclast formation from hematopoietic cells via regulation of various transcription factors. Here, we show that MafB negatively regulates RANKL-induced osteoclast differentiation. Expression levels of MafB are significantly reduced by RANKL during osteoclastogenesis. Overexpression of MafB in bone marrow-derived monocyte/macrophage lineage cells (BMMs) inhibits the formation of TRAP+ multinuclear osteoclasts, but phagocytic activity of BMMs is retained. Furthermore, overexpression of MafB in BMMs attenuates the gene induction of NFATc1 and osteoclast-associated receptor (OSCAR) during RANKL-mediated osteoclastogenesis. In addition, MafB proteins interfere with the DNA-binding ability of c-Fos, Mitf, and NFATc1, inhibiting their transactivation of NFATc1 and OSCAR. Furthermore, reduced expression of MafB by RNAi enhances osteoclastogenesis and increases expression of NFATc1 and OSCAR. Taken together, our results suggest that MafB can act as an important modulator of RANKL-mediated osteoclastogenesis.
Serotonin provides an accessory signal to enhance T-cell activation by signaling through the 5-HT7 receptor
Authors: León-Ponte, Matilde , Ahern Gerard P. , O'Connell Peta J. 
Published: December 2006

AbstractAlthough typically considered a neurotransmitter, there is substantial evidence that serotonin (5-HT) plays an important role in the pathogenesis of inflammatory disorders. Despite these findings, the precise role of 5-HT in modulating immune function, particularly T-cell function, remains elusive. We report that naive T cells predominantly express the type 7 5-HT receptor (5-HTR), and expression of this protein is substantially enhanced on T-cell activation. In addition, T-cell activation leads to expression of the 5-HT1B and 5-HT2A receptors. Significantly, exogenous 5-HT induces rapid phosphorylation of extracellular signal-regulated kinase-1 and -2 (ERK1/2) and IκBα in naive T cells. 5-HT–induced activation of ERK1/2 and NFκB is inhibited by preincubation with a specific 5-HT7 receptor antagonist. Thus, 5-HT signaling via the 5-HT7 receptor may contribute to early T-cell activation. In turn, 5-HT synthesized by T cells may act as an autocrine factor. Consistent with this hypothesis, we found that inhibition of 5-HT synthesis with parachlorophenylalanine (PCPA) impairs T-cell activation and proliferation. Combined, these data demonstrate a fundamental role for 5-HT as an intrinsic cofactor in T-cell activation and function and suggest an alternative mechanism through which immune function may be regulated by indoleamine 2,3-dioxygenase–mediated catabolism of tryptophan.
A review of interventions triggered by hepatitis A infected food-handlers in Canada
Authors: Tricco Andrea C , Pham Ba' , Duval Bernard , De Serres Gaston , Gilca Vladimir , Vrbova Linda , Anonychuk Andrea , Krahn Murray , Moher David 
Published: December 2006

Abstract
Background
In countries with low hepatitis A (HA) endemicity, infected food handlers are the source of most reported foodborne outbreaks. In Canada, accessible data repositories of infected food handler incidents are not available. We undertook a systematic review of such incidents to evaluate the extent of viral transmission through food contamination and the scope of post-exposure prophylaxis (PEP) interventions.

Methods
A systematic search of MEDLINE and EMBASE was conducted to identify published reports of incidents in Canada. An expanded search of a news repository (i.e., transcripts from newspapers and newscasts) was also conducted to identify the location and timing of an incident, which was used to retrieve the related report by contacting local public health departments. Data pertaining to case identification, public health risk, PEP interventions, and associated costs was independently abstracted by two reviewers and summarized according to incidents with and without large PEP interventions.

Results
A total of 16 incidents were identified from 1998–2004. There were approximately 3 incidents requiring public notification per year. Only 12.5% of incidents were described in published reports, indicating that published data significantly underestimated the number of incidents and PEP interventions. Data pertaining to the remaining incidents was unpublished, sparse and highly dispersed at the local public health level.
Six of the 16 incidents required large PEP interventions to immunize on average 5000 potentially exposed individuals. Secondary transmission was low. Characteristics of incidents requiring large PEP interventions included potentially infectious food handlers working with uncooked food for a prolonged duration in high-volume grocery stores in high-density urban areas.

Conclusion
Infected food handlers with hepatitis A virus (HAV) requiring public notification are not infrequent in Canada. Published data severely underestimated the burden of PEP intervention. Better and consistent reporting at the local and national level as well as a national data repository should be considered for the management of future incidents.
Tumor cell invasion of collagen matrices requires coordinate lipid agonist-induced G-protein and membrane-type matrix metalloproteinase-1-dependent signaling
Authors: Fisher Kevin E , Pop Andreia , Koh Wonshill , Anthis Nicholas J , Saunders W Brian , Davis George E 
Published: December 2006

Abstract

Background
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are bioactive lipid signaling molecules implicated in tumor dissemination. Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a membrane-tethered collagenase thought to be involved in tumor invasion via extracellular matrix degradation. In this study, we investigated the molecular requirements for LPA- and S1P-regulated tumor cell migration in two dimensions (2D) and invasion of three-dimensional (3D) collagen matrices and, in particular, evaluated the role of MT1-MMP in this process.

Results
LPA stimulated while S1P inhibited migration of most tumor lines in Boyden chamber assays. Conversely, HT1080 fibrosarcoma cells migrated in response to both lipids. HT1080 cells also markedly invaded 3D collagen matrices (~700 μm over 48 hours) in response to either lipid. siRNA targeting of LPA1 and Rac1, or S1P1, Rac1, and Cdc42 specifically inhibited LPA- or S1P-induced HT1080 invasion, respectively. Analysis of LPA-induced HT1080 motility on 2D substrates vs. 3D matrices revealed that synthetic MMP inhibitors markedly reduced the distance (~125 μm vs. ~45 μm) and velocity of invasion (~0.09 μm/min vs. ~0.03 μm/min) only when cells navigated 3D matrices signifying a role for MMPs exclusively in invasion. Additionally, tissue inhibitors of metalloproteinases (TIMPs)-2, -3, and -4, but not TIMP-1, blocked lipid agonist-induced invasion indicating a role for membrane-type (MT)-MMPs. Furthermore, MT1-MMP expression in several tumor lines directly correlated with LPA-induced invasion. HEK293s, which neither express MT1-MMP nor invade in the presence of LPA, were transfected with MT1-MMP cDNA, and subsequently invaded in response to LPA. When HT1080 cells were seeded on top of or within collagen matrices, siRNA targeting of MT1-MMP, but not other MMPs, inhibited lipid agonist-induced invasion establishing a requisite role for MT1-MMP in this process.

Conclusion
LPA is a fundamental regulator of MT1-MMP-dependent tumor cell invasion of 3D collagen matrices. In contrast, S1P appears to act as an inhibitory stimulus in most cases, while stimulating only select tumor lines. MT1-MMP is required only when tumor cells navigate 3D barriers and not when cells migrate on 2D substrata. We demonstrate that tumor cells require coordinate regulation of LPA/S1P receptors and Rho GTPases to migrate, and additionally, require MT1-MMP in order to invade collagen matrices during neoplastic progression.