bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metachromasy in clay dye systems: the adsorption of acridine orange by Na-beidellite
Authors: Garfinkel-Shweky D. , Yariv S. 
Published: July 2002

AbstractThe adsorption of the metachromic dye acridine orange (AO) by Na-beidellite was investigated by visible spectroscopy. Different types of clay-AO association were identified from the appearance and location of absorption bands α or β. The colloidal properties were determined from curves of the absorbance vs. the degree of saturation. Three regions were identified in the absorbance curve. In the first region beidellite is peptized with small amounts of AO and the dye penetrates into the interlayer space where it undergoes metachromasy due to π interactions between the aromatic entity and the oxygen plane of the clay. With larger amounts of AO (second region), the clay flocculates due to the aggregation of the dye cations in the interparticle space of the flocs. In excess AO (third region), beidellite is gradually peptized, forming small tactoids with monomeric AO in the interlayer space and at the same time adsorbing dimeric and polymeric AO cationic species at the solid-liquid interface. Compared with the other smectites, AO shows the greatest tendency to undergo metachromasy in the presence of beidellite.
I1̄ – I2/c ferroelastic phase transition in the Ca0.2Pb0.8Al2Si2O8 feldspar as a function of temperature
Authors: Benna P. , Tribaudino M. , Bruno E. 
Published: July 2002

AbstractFeldspar of composition Ca0.2Pb0.8Al2Si2O8 (PbF80An20) was synthesized from melt and subsequently isothermally annealed at T = 960°C for 4 days. In situ HT X-ray powder spectra of PbF80An20 feldspar, triclinic I1̄ at room temperature, were collected in the temperature range 20–800°C, and a displacive continuous ferroelastic transition to a I2/c monoclinic phase was observed. An analysis of the symmetry-required components of the spontaneous strain tensor reveals the second order character (β = 0.46 ± 0.02) of the transition with TC = 680 ± 15°C. A linear coupling was observed between the e4 and e6 components of the spontaneous strain. The transition is analogous to those observed, with increasing temperature, along the join An–SrF and in disordered Na-rich alkali feldspars. A comparison with Ca0.2Sr0.8Al2Si2O8 feldspar (TC = 680°C, McGuinn and Redfern, 1997) shows that PbF80An20 has a higher spontaneous strain (εs = 0.028 in PbF80An20vs 0.020 in Ca0.2Sr0.8Al2Si2O8) and a higher e4 component, possibly related to the higher distortion of the non-tetrahedral polyhedron in lead feldspar.
Iron-rich and iron-poor prehnites from the Way Linggo epithermal Au-Ag deposit, southwest Sumatra, and the Heber geothermal field, California
Authors: Wheeler R. S. , Browne P. R. L. , Rodgers K. A. 
Published: July 2002

AbstractElectron microprobe analyses of prehnites from the Way Linggo low-sulphidation epithermal Au-Ag deposit of southern Sumatra, show that the mole fraction of octahedral Fe3+, expressed as Fe3+/(Fe3++AlVI), ranges from 0.0 to ~0.6, the higher values being among the most iron-rich reported for prehnite in a hydrothermal environment. Prehnites from a diabase sill in the Heber geothermal field of California have mole fractions of octahedral Fe3+ ranging from 0.03 to 0.3. The Way Linggo prehnites formed below 220°C, some 20–30°C lower than those at the Heber field; the lower crystallization temperatures perhaps enhanced the opportunity for Fe3+ to substitute in octahedral sites. In both occurrences, prehnite predates late-stage calcite, consistent with the need for waters depositing prehnite to have aCO2 <0.01 moles. At higher CO2 activities the stability field of calcite would swamp the range of aCa2+/aH+ values appropriate for crystallizing prehnite. Consequently, the presence of prehnite in a hydrothermal environment primarily indicates that degassing of the hydrothermal fluid in CO2 occurred prior to deposition.
Use of organo-zeolitic fertilizer to sustain plant growth and stabilize metallurgical and mine-waste sites
Authors: Leggo P. J. , Ledésert B. 
Published: July 2002

AbstractLand south of Lille, contaminated by heavy metals from local metal refining, has become the subject of intensive research. Topsoil from this area is used in the current work to investigate the growth behaviour of Spring wheat (Triticum aestivum L., cv. Paragon) when amended with organo-zeolitic fertilizer. Research has shown that soil substrates amended with ammoniated zeolitic tuff promote large populations of nitrifying bacteria which, as the result of ensuing enzyme reactions, produce available nitrogen together with H+ ions. It appears that the proton activity promotes cation mobilization allowing plant uptake to reach levels which, to a large extent, satisfy the nutritional requirements of the plant; only in the case of Zn is the level far exceeded. Very large differences in plant morphology occur when plants are grown in the amended substrates and the resulting development of large dense root systems, which have the ability to bind soil particles, are particularly important in their ability to reduce surface erosion and pollution from run-off.
The crystal structure of Na4(UO2)(CO3)3 and its relationship to schröckingerite
Authors: Li Yaping , Krivovichev S. V. , Burns P. C. 
Published: July 2002

AbstractCrystals of the compound Na4(UO2)(CO3)3 have been synthesized and the structure has been solved. It is trigonal with a= 9.3417(6), c = 12.824(1) Å, V = 969.2(1) Å3, space group Pc1 and Z = 4. The structure was refined on the basis of F2 (wR2 = 4.2%) for all unique data collected using Mo-Kα X-radiation and a CCD-based detector. The final R1 was 2.0%, calculated for 534 unique observed (Fo ≥ 4σF) reflections, and the goodness-of-fit (S) was 0.91. The structure contains a uranyl tricarbonate cluster composed of a uranyl hexagonal bipyramid that shares three equatorial edges with CO3 triangles. The uranyl tricarbonate clusters are connected through NaO6 and NaO5 polyhedra, forming a heteropolyhedral framework structure. This compound may be related to a uranyl carbonate phase with the same composition which has been reported as an alteration phase on the surface of Chernobyl ‘lava’, and as a mineral in the Jachymov ore district, Czech Republic.
Magma replenishment, and the significance of poikilitic texlures, in the Lower Main Zone of the western Bushveld Complex, South Africa
Authors: Mitchell Andrew A. , Eales Hugh V. , Johan Kruger F. 
Published: July 2002

AbstractPetrographic and compositional variations in the Lower Main Zone (LMZ) of the western Bushveld Complex indicate changing regimes of magma replenishment. The lowermost unit of the LMZ, designated N-I, is an enigmatic sequence of leuconoritic cumulates, characterized primarily by up-sequence increases in both orthopyroxene Mg# and whole-rock Sr isotope initial ratio. The Sr isotope profile of N-I is ascribed to injection and progressive integration of small influxes of fresh magma with high (Main Zone-type) Sr isotope initial ratios. The basal Fe-enrichment in N-I, on the other hand, is ascribed to a separate, later mechanism involving the downward migration of late-stage Fe-rich liquids. The overlying two units, N-II and G-I, delineated chiefly in terms of basal Mg-enrichment of orthopyroxene, are ascribed to injections of fresh magma into the chamber. Poikilitic orthopyroxene grains in the basal parts of both N-II and G-I suggest entrainment and partial resorption of plagioclase grains from the semi-crystalline resident material into which the fresh magma was intruded.
The kinetics of dehydration in Ca-montmorillonite: an in situ X-ray diffraction study
Authors: Bray Helen J. , Redfern Simon A. T. , Clark Simon M. 
Published: July 2002

AbstractThe thermal dehydration of naturally occurring Ca-montmorillonite has been studied by in situ X-ray diffraction at temperatures between 60–120°C. The time-temperature-dependence of the position of the basal (001) reflection reveals that interlayer water loss on isothermal dehydration occurs in two stages. After an initial rapid decrease in interlayer spacing (on shock heating to an isothermal soak temperature) the reaction proceeds towards equilibrium more slowly. Furthermore, the width of the (001) reflection changes with time, reflecting transformation-dependent changes in homogeneity perpendicular to (001) with a maximum in peak width at the point where the rate of the reaction appears to change. This suggests that, as the interlayer spacing collapses, a local change is induced in the structure, affecting the means of movement of the water from the interlayer.
Lueshite, pyrochlore and monazite-(Ce) from apatite-dolomite carbonatite, Lesnaya Varaka complex, Kola Peninsula, Russia
Authors: Chakhmouradian A. R. , Mitchell R. H. 
Published: July 2002

AbstractApatite-dolomite carbonatite at Lesnaya Varaka, Kola Peninsula, Russia, hosts intricate mineral intergrowths composed of lueshite in the core and pyrochlore-group minerals in the rim. Lueshite is a primary Nb-bearing phase in the carbonatite and ranges in composition from cerian lueshite to almost pure NaNbO3. For comparison, the compositional variation of lueshite from the Kovdor and Sallanlatvi carbonatites is described. At Lesnaya Varaka, lueshite is replaced by nearly stoichiometric Na-Ca pyrochlore due to late-stage re-equilibration in the carbonatite system. X-ray powder diffraction data for both minerals are presented. Barian strontiopyrochlore, occurring as replacement mantles on Na-Ca pyrochlore, contains up to 43% Sr and 8–18% Ba at the A-site, and shows a high degree of hydration and strong ionic deficiency at the A- and Y-sites. This mineral is metamict and, upon heating, recrystallises to an aeschynite-type structure. Monazite-(Ce) found as minute crystals in fractures, represents the solid solution between monazite-(Ce) CePO4, brabantite CaTh(PO4)2 and SrTh(PO4)2. Our data indicate the high capacity of the monazite structure for Th and accompanying divalent cations at low temperatures and pressures that has a direct relevance to solving the problem of long-term conservation of radioactive wastes. Monazite-(Ce) and barian strontiopyrochlore are products of low-temperature hydrothermal or secondary (hypergene) alteration of the primary mineral assemblage of the carbonatite.
Occurrence of primary almandine-spessartine-rich garnet and zinnwaldite
phenocrysts in a Neogene rhyolite on the island of Chios, Aegean Sea,
Greece
Authors: Mitropoulos P. , Katerinopoulos A. , Kokkinakis A. 
Published: July 2002

Abstract
Primary almandine and spessartine-rich garnet and zinnwaldite phenocrysts
occur along with feldspar (plagioclase and sanidine) phenocrysts, in the rhyolite
of Profitis Ilias, which is located on the SE coast of the island of Chios,
Greece. The distinctive mineralogical composition of this rhyolite is described.
Although formed in the back-arc tectonic environment of the Aegean volcanic arc,
the Profitis llias rhyolite shows significant trace element compositional
differences when compared with typical arc or back-arc volcanic rocks of the area.
It shows extreme depletion in Sr and Ba and enrichment in Nb and Mn, and has much
more affinity with A-type granites and particularly Li-mica granites.
Apparently, both zinnwaldite and spessartine-rich garnet can be generated as
primary phases from a granite melt enriched in volatile constituents at low
P–T. This granite melt
could be the residual product of an un-exposed, earlier formed, typical back-arc
granite of the area, enriched in volatile constituents from a subcrustal source
above the active mantle of the eastern Aegean area.
The extensive and deep faulting in the broad eastern Aegean lithosphere
section would have facilitated the rapid ascent of that volatile-enriched granite
melt, the parent of the Profitis Ilias rhyolite.
The interaction of human peripheral blood eosinophils with bacterial lipopolysaccharide is CD14 dependent
Authors: Plötz Sabine G. , Lentschat Arnd , Behrendt Heidrun , Plötz Werner , Hamann Lutz , Ring Johannes , Rietschel Ernst Th. , Flad Hans-Dieter , Ulmer Artur J. 
Published: July 2002

AbstractBacterial lipopolysaccharide (LPS, endotoxin) is a ubiquitous component of dust and air pollution and is suspected to contribute after inhalation to an activation of eosinophils in bronchial tissues of asthmatic patients, provoking inflammatory and allergic processes. We were therefore interested in the interaction of eosinophil granulocytes with LPS and have examined the activation of and uptake to human peripheral blood eosinophils by LPS. Eosinophils were stimulated by LPS and the endotoxic component lipid A and the release of tumor necrosis factor alpha (TNF-α) and of the eosinophil-specific granule protein eosinophil cationic protein (ECP) was estimated. The results show induction of TNF-α and ECP-release by LPS and lipid A in a dose-dependent manner. Anti-CD14 monoclonal antibody (moAb) (clone MEM-18) and the synthetic lipid A partial structure 406 blocked the release of TNF-α and ECP by LPS-stimulated eosinophils. Studies with radioactively labeled LPS showed dose-dependent uptake of3H-LPS to eosinophils. The 3H-LPS uptake was found to be specific because preincubation with unlabeled LPS, compound 406 and also anti-CD14 antibodies inhibited uptake of3H-LPS to eosinophil granulocytes. By flow cytometry using anti-CD14 moAb and by reverse transcriptase-polymerase chain reaction (RT-PCR) technique, CD14 expression was detectable. Furthermore, messenger RNA (mRNA) expression of Toll-like receptors (TLR) 2 and TLR 4 was detected, indicating the presence of these CD14 coreceptors. The results indicate that eosinophils can take up LPS and can be stimulated by LPS in a CD14-dependent manner. Hence, in addition to allergens, eosinophils interact with endotoxin, a process that possibly exacerbates ongoing inflammatory and allergic processes.
Characterization of human sialoadhesin, a sialic acid binding receptor expressed by resident and inflammatory macrophage populations
Authors: Hartnell Adele , Steel Jane , Turley Helen , Jones Margaret , Jackson David G. , Crocker Paul R. 
Published: July 2002

AbstractSialoadhesin is a macrophage-restricted cellular interaction molecule and a prototypic member of the Siglec family of sialic acid binding immunoglobulin (Ig)-like lectins. So far, it has only been characterized in rodents. Here, we report the molecular cloning, binding properties, and expression pattern of human sialoadhesin. The predicted protein sequences of human and mouse sialoadhesin are about 72% identical, with the greatest similarity in the extracellular region, which comprises 17 Ig domains in both species. A recombinant protein consisting of the first 4 N-terminal domains of human sialoadhesin fused to the Fc region of human IgG1 mediated sialic acid–dependent binding with a specificity similar to its mouse counterpart, preferring sialic acid in the α2,3 glycosidic linkage over the α2,6 linkage. By flow cytometry with peripheral blood leukocytes, recombinant sialoadhesin bound strongly to granulocytes with intermediate binding to monocytes, natural killer cells, B cells, and a subset of CD8 T cells. Using antibodies raised to the recombinant protein, sialoadhesin was immunoprecipitated from the THP-1 human monocytic cell line as an approximate 200-kd glycoprotein. The expression pattern of human sialoadhesin was found to be similar to that of the mouse receptor, being absent from monocytes and other peripheral blood leukocytes, but expressed strongly by tissue macrophages in the spleen, lymph node, bone marrow, liver, colon, and lungs. High expression was also found on inflammatory macrophages present in affected tissues from patients with rheumatoid arthritis.
A randomized comparison between rasburicase and allopurinol in children with lymphoma or leukemia at high risk for tumor lysis
Authors: Goldman Stanton C. , Holcenberg John S. , Finklestein Jerry Z. , Hutchinson Raymond , Kreissman Susan , Johnson F. Leonard , Tou Conrad , Harvey Elizabeth , Morris Erin , Cairo Mitchell S. 
Published: July 2002

AbstractStandard therapy in the United States for malignancy-associated hyperuricemia consists of hydration, alkalinization, and allopurinol. Urate oxidase catalyzes the enzymatic oxidation of uric acid to a 5 times increased urine soluble product, allantoin. Rasburicase is a new recombinant form of urate oxidase available for clinical evaluation. This multicenter randomized trial compared allopurinol to rasburicase in pediatric patients with leukemia or lymphoma at high risk for tumor lysis. Patients received the assigned uric acid-lowering agent for 5 to 7 days during induction chemotherapy. The primary efficacy end point was to compare the area under the serial plasma uric acid concentration curves during the first 96 hours of therapy (AUC0-96). Fifty-two patients were randomized at 6 sites. In an intent-to-treat analysis, the mean uric acid AUC0-96 was 128 ± 70 mg/dL.hour for the rasburicase group and 329 ± 129 mg/dL.hour for the allopurinol group (P &lt; .0001). The rasburicase versus allopurinol group experienced a 2.6-fold (95% CI: 2.0-3.4) less exposure to uric acid. Four hours after the first dose, patients randomized to rasburicase compared to allopurinol achieved an 86% versus 12% reduction (P &lt; .0001) of initial plasma uric acid levels. No antirasburicase antibodies were detected at day 14. This randomized study demonstrated more rapid control and lower levels of plasma uric acid in patients at high risk for tumor lysis who received rasburicase compared to allopurinol. For pediatric patients with advanced stage lymphoma or high tumor burden leukemia, rasburicase is a safe and effective alternative to allopurinol during initial chemotherapy.
The relative quiescence of hematopoietic stem cells in nonhuman primates
Authors: Mahmud Nadim , Devine Steven M. , Weller Kevin P. , Parmar Simrit , Sturgeon Cord , Nelson Mary C. , Hewett Terry , Hoffman Ronald 
Published: July 2002

Abstract
Quiescence has been thought to be required for the retention of the full biological potential of pluripotent hematopoietic stem cells (PHSCs). This hypothesis has been challenged recently by the observation that all murine PHSCs cycle continuously and constantly contribute to steady-state blood cell production. It was asked whether these observations could be extrapolated to describe hematopoiesis in higher mammals. In this series of experiments, the replicative history of PHSCs was examined in baboons by continuously administering bromodeoxyuridine (BrdU) for more than 85 weeks. The results indicate that under steady-state conditions, PHSCs remain largely quiescent but do cycle, albeit at a far lower rate than previously reported for rodent PHSCs. BrdU-labeled cycling PHSCs and progenitor cells were shown to have an extensive proliferative capacity and to contribute to blood cell production for prolonged periods of time. The proportion of PHSCs entering cell cycle could, however, be rapidly increased by the in vivo administration of granulocyte-colony stimulating factor. These data indicate that during steady-state hematopoiesis, baboon PHSCs require prolonged periods of time to cycle and that the proportion of PHSCs in cycle is not fixed but can be altered by external stimuli. The relative quiescence of PHSCs observed in this nonhuman primate model, in contrast to murine PHSCs, might explain the current barriers to genetic modification and ex vivo expansion of human PHSCs.
B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease
Authors: Bräuninger Andreas , Yang Wentao , Wacker Hans-Heinrich , Rajewsky Klaus , Küppers Ralf , Hansmann Martin-Leo 
Published: July 2002

AbstractProgressively transformed germinal centers (PTGCs) are histologic structures mainly composed of small resting B cells and intermingled proliferating centroblast-like cells. The B-cell differentiation processes within PTGCs and their relation to classical germinal centers (GC) and to lymphocyte-predominant Hodgkin disease (LPHD), with which PTGCs are often associated, are largely unknown. To address these issues, single small resting (Ki67−) and proliferating (Ki67+) centroblast-like cells were isolated from 7 PTGCs of 5 lymph nodes, and rearranged immunoglobulin genes were amplified and sequenced. Most small resting B cells were clonally unrelated, and most carried unmutated immunoglobulin gene rearrangements resembling mantle zone B cells. Small resting B cells with mutated immunoglobulin gene rearrangements may represent centrocytes, memory B cells, or both. Among the centroblast-like Ki67+ cells, expanded B-cell clones were observed in 6 of 7 PTGCs analyzed. Clonally related V region genes showed extensive intraclonal diversity, and the mutation pattern indicated stringent selection of the cells for the expression of functional antigen receptors. Thus, somatic hypermutation, clonal expansion, and selection occur also in the disorganized PTGC microenvironment, as in classical GCs. In lymph nodes affected by PTGCs, no clonal expansion across the borders of individual PTGCs was observed, distinguishing PTGCs from LPHD.
V H 1-69 gene is preferentially used by hepatitis C virus–associated B cell lymphomas and by normal B cells responding to the E2 viral antigen
Authors: Chan Chunghuang Hubert , Hadlock Kenneth G. , Foung Steven K. H. , Levy Shoshana 
Published: July 2002

AbstractHepatitis C virus (HCV)–associated B cell lymphomas were previously shown to express a restricted repertoire of immunoglobulin VH and VL genes, VH1-69 and VκA27, respectively. Although this suggests a role for antigen selection in the pathogenesis of these lymphomas, the driving antigen involved in the clonal expansion has not been identified. B cell response to a viral antigen, the HCV envelope glycoprotein 2 (E2), was analyzed in an asymptomatic HCV-infected patient. Single B cells, immortalized as hybridomas and selected for binding E2, were analyzed for their V gene usage. Sequences of these V region genes demonstrated that each hybridoma expressed unique VH and VLgenes. Remarkably, these anti-E2 hybridomas preferentially used the VH1-69 gene. Analysis of replacement to silent mutation ratios indicated that the genes underwent somatic mutation and antigenic selection. In a separate report, human anti-E2 antibodies were also shown to express the same VH gene. These data strengthen the hypothesis that the HCV-associated lymphomas are derived from clonally expanded B cells stimulated by HCV.