bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet microparticle formation and thrombin generation under high shear are effectively suppressed by a monoclonal antibody against GPIbα
Authors: Pontiggia Luca , Steiner Beat , Ulrichts Hans , Deckmyn Hans , Forestier Marc , Beer Jürg 
Published: December 2006

SummaryWe studied the inhibition of platelet microparticle (MP) formation and thrombin generation under high shear forces. We hypothesized that an inhibitor of the GPIbα-von Willebrand factor (vWF) interaction would be more effective in suppressing MP formation and thrombin generation than GPIIb/IIIa inhibitors. Platelet-rich plasma (PRP) anticoagulated with PPACK (D-Phe-Pro-Arg chloromethyl ketone) was exposed in a coneand-plate viscometer (shear: 5,000 s−1 for5 min) in the presence of antagonists to GPIbα (the monoclonal antibody [Mab] Ib-23) or to GPIIb/IIIa (abciximab, tirofiban, eptifibatide) at their IC90 determined in platelet aggregometry with ristocetin or ADP, respectively. We used double labeling (CD41-PE and annexin-V-FITC) for flow cytometric detection of MP and their aminophospholipid exposure. Thrombin generation was measured using PRP prepared fromACD anticoagulated blood. About 40% of the thrombin generation was found to be mediated by the MP fraction of the PRP. Blockade of GPIbα with Mab Ib-23 reduced MP formation and thrombin generation by 50%, and was more effective than any GPIIb/IIIa antagonist. The combination of Mab Ib-23 with one of the GPIIb/IIIa inhibitors further reduced the MP formation to ∼30%. The antibody also partially inhibited thrombin induced platelet aggregation. Epitope mapping suggested that Mab Ib-23 binds between the amino acids 201 and 268 of GPIbα, explaining the interference with vWF and thrombin interaction. In contrast to the commonly used GPIIb/IIIa antagonists, the blockade of GPIbα with Mab Ib-23 effectively reduces the prothrombotic MP generation and thrombin formation at shear rates typically found in arterial stenoses.
Chronological expression of PAR isoforms in acute liver injury and its amelioration by PAR2 blockade in a rat model of sepsis
Authors: Jesmin Subrina , Zaedi Sohel , Sakuraya Fumika , Gando Satoshi 
Published: December 2006

SummaryThe liver can be injured and its functions altered by activation of the coagulation and inflammatory processes in sepsis. The objective of the present study was to investigate the pattern of protease-activated receptors (PARs) over time in a model of acute liver injury induced by lipopolysaccharide (LPS); and whether PARs playa role in this process and exert their effects through inflammation and coagulation. Levels of tumor necrosis factor-α (TNF-α) were significantly expressed 1 h after LPS administration followed by: i) an increase in levels of tissue factor, factor VIIa, thrombin and plasminogen activator inhibitor-1; ii) unchanged or steady levels of tissue factor pathway inhibitor; and iii) subsequent deposition of fibrin in the liver tissue, that led to the elevation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), which are associated with liver injury. The expression of all PAR isoforms (1–4) was elevated, and each isoform had a distinct cellular localization (hepatocytes, Kupffer cells, the portal triad area, and central veins) and a time-dependent pattern of expression. The immuno-reactivity of PAR2 and 4 in Kupffer cells was intense. Interestingly, PAR2 blocking peptide improved the healing of liver injuries, an effect that was associated with suppression of TNF-α elevation, and normalization of coagulation and fibrinolysis. This ultimately led to decreased fibrin formation in the injured liver. The present study reveals a distinct chronological expression and cellular localization of PARs in LPS-mediated liver injury and shows that blockade of PAR2 may playa crucial role in treating liver injury, via normalization of inflammation, coagulation and fibrinolytic pathways.
Tiplaxtinin impairs nutritionally induced obesity in mice
Authors: Alessi Marie-Christine , Frederix Liesbeth , Collen Désiré , Juhan-Vague Irène , Lijnen H. 
Published: December 2006

SummaryTo investigate the effect of tiplaxtinin, designed as a synthetic inhibitor of plasminogen activator inhibitor-1 (PAI-1), on obesity, male C57Bl/6 mice (13–14 weeks old) were kept on a high-fat diet (20.1 kJ/g) for four weeks without or with addition of tiplaxtinin (PAI-039) at a dose of 2 mg/g food. At the time of sacrifice, body weights were significantly lower in the inhibitor-treated mice (p < 0.0005). The weights of the isolated subcutaneous and gonadal fat deposits were also significantly lower (both p < 0.0005), associated with adipocyte hypotrophy. Inhibitor-treated adipose tissues displayed similar blood vessel size, but a higher blood vessel density. Fasting glucose and insulin levels, as well as glucose-tolerance tests were not significantly affected by the inhibitor treatment, whereas plasma triglyceride levels were significantly reduced (p = 0.02) and LDL-cholesterol levels significantly enhanced (p = 0.0002). Insulin-tolerance tests revealed significantly lower glucose levels at the end of the test in the inhibitor treated mice (p = 0.03). Thus, in this model of diet-in-duced obesity in mice administration of tiplaxtinin resulted in impaired adipose tissue development.
Differential effects of the loss of intrachain- versus interchain-disulfide bonds in the cystine-knot domain of von Willebrand factor on the clinical phenotype of von Willebrand disease
Authors: Tjernberg Pernilla , Vos Hans , Spaargaren-van Riel Caroline , Luken Brenda , Voorberg Jan , Bertina Rogier , Eikenboom Jeroen 
Published: December 2006

SummaryVon Willebrand factor (VWF) contains a large number of cysteine residues, which all form disulfide bonds. Mutations of cysteines located in the cystine-knot (CK) domain of VWF have been identified in both qualitative type 2A (IID) and quantitative type 3 vonWillebrand disease (VWD).Our objective was to test the hypothesis that the difference in phenotype is related to whether the mutated cysteine residue is involved in either interchain- or intrachain-disulfide-bond formation. The effects of three cysteine mutations which are all located in the CK-domain of VWF, C2773S (type 2A(IID)), C2739Y (type 3), and C2754W (type 3), were studied by transient expression in 293T cells. Cotransfection of wild-type (wt) and C2773S VWF constructs reproduced the plasma phenotype of heterozygous type 2A(IID) patients, with normal to high levels of VWF antigen (VWF:Ag), absence of high-molecular-weight multimers, and the presence of intervening bands between the normal multimers.In contrast, single transfections of C2739Y or C2754W resulted in a quantitativeVWF defect with lowVWF:Ag levels, and co-transfections of wt and mutant constructs resulted in a 50% reduction of VWF:Ag and only a minor effect on VWF multimerization. We demonstrated N-terminal dimerization of VWF-C2773S and both Nand C-terminal dimerization of VWF-C2754W. Our data suggest that loss of a single disulfide bond in the CK-domain ofVWF leads toa recessive, quantitativeVWF deficiency if an intrachain-disulfide bond is involved, and to a dominant-negative, qualitative defect of VWF if an interchain-disulfide bond is involved.
High-spacing irregularly interstratified layer-silicates in the alluvial soil clays of Meerut, India
Authors: Tomar K. P. 
Published: December 2006

AbstractThe mineralogy of the fine clay fraction (<0·2 μm) of two soil pedons (Aquic and Udic Haplustalfs) representing the wheat-sugarcane belt of the Indo-Gangetic alluvial plain was studied by X-ray diffraction, differential thermal analysis, transmission electron microscopy, and by chemical analysis. The XRD patterns are characterized by unusually high spacings which are interpreted in terms of an interstratification comprising smectite, illite and ‘chlorite’ components. The CEC data (Ca/Mg and K/NH4) also indicate the possible presence of vermiculite. A plateau bridging the 7–10 Å maxima in K-saturated specimens heated at 300°C suggests interstratification of kaolinite and smectite, although this may not be part of the above interstratification. The diffuse bands shown by Mg-glycerol-solvated Ap-horizon clays at ∼21 Å, and the increasing elimination of XRD peaks in the > 10 Å region with distance from the surface, suggests that the expanding layers have a slight tendency to segregate in Ap horizon samples and that randomization tends to increase with depth. Discrete illite and small amounts of kaolinite were also detected.
An 57Fe Mossbauer effect study on glauconites from different locations in Belgium and Northern France
Authors: De Grave E. , Vandenbruwaene J. , Elewaut E. 
Published: December 2006

AbstractSixteen glauconite samples from different locations in Belgium and Northern France were investigated by 57Fe Mössbauer spectroscopy at room temperature. The spectra were fitted with three Fe3+ and two Fe2+ doublets, both Fe species occupying M1(trans) and M2(cis) sites in the T-O-T layers. The third Fe3+ doublet was assigned to interlayer ferric complexes. The observed Mössbauer parameters did not show significant variations from sample to sample. No direct relation between K and Fe content was observed, although within some distinct groups (e.g. Bande Noire, Cenomanian) the amount of Fe2+ increased with increasing K content.
Characterization of smectites synthesised from zeolites and mechanism of smectite synthesis
Authors: Komarneni S. , Breval E. 
Published: December 2006

AbstractSmectites were synthesised hydrothermally from zeolites in an Mg-rich brine at 300°C under a confining pressure of 30 MPa and characterized by XRD using the Greene-Kelley Li-saturation test and the K+-saturation/glycolation test. The synthetic smectites were found to be dioctahedral with only tetrahedral negative layer charge; the layer charge was also deduced to be low and they are classified as beidellites. The mechanism of formation includes H+saturation of zeolites by the hydrolysis of Mg2+under hydrothermal conditions, followed by decomposition of the zeolites and recrystallization to beidellites. These results show that solution chemistry is an important factor affecting stability of zeolites under hydrothermal conditions.
Mineralogical evidence for sediment derivation and ice movement within the Wash drainage basin, eastern England
Authors: Wilmot R. D. 
Published: December 2006

AbstractThe Wash drainage basin contains four principal river systems. Samples were collected from the freshwater and estuarine reaches of each of these, and silt- and clay-grade fractions were separated and examined by XRD. The clay mineralogy of each of the rivers is different; in the north the Witham sediments contain chlorite, the Welland and Nene samples contain vermiculite, with a higher proportion of kaolinite in the former, while in the south the Ouse sediments contain smectite. The clay fractions of the samples from the estuarine reaches all contain chlorite, confirming that non-fluvial sources must contribute to the sediments of the Wash. Comparison of this pattern of clay mineralogy with that for the underlying Jurassic and Cretaceous rocks shows that there was relatively little modification during the Pleistocene glacial periods. Such a pattern supports recent work which suggests that ice moved through the Wash gap and then fanned out from the Fenland area, rather than entering the region from the north.
Vermiculites hydratees a une couche
Authors: De La Calle C. , Suquet H. , Pezerat H. 
Published: December 2006

ResumeLes hydrates à une couche des vermiculites présentent cinq modes d'empilement. Aux cations de petit et de grand rayon ionique (Li et Ba) correspondent des modes d'empilement particuliers. Les cations (Na, Mg, Ca et Sr) conduisent chacun à deux modes d'empilement correspondant à deux stades différents d'hydratation.
Electron spin resonance studies of montmorillonites
Authors: Crăciun C. , Meghea Aurelia 
Published: December 2006

AbstractSixteen montmorillonites (8 normal and 8 abnormal using DTA dehydroxylation criteria) from the Gurasada bentonite deposits, Romania, were investigated by ESR. The spectra showed two features: ag= 4·3 signal attributed to isolated Fe3+ions and a broad resonance withg∼ 2·0 which was interpreted as arising from exchange interactions between clusters of Fe3+ions. Additional experiments suggested that the latter resonance could have a structural component. The line-shape of the two resonances varied between normal and abnormal montmorillonites, indicating that the distribution of the Fe3+ions between internal phase (montmorillonite lattice) and external phase (montmorillonite surface) was different for the two varieties.
Order-disorder in 1:1 type clay minerals by solid-state27Al and29Si magic-angle-spinning NMR spectroscopy
Authors: Komarneni S. , Fyfe C. A. , Kennedy G. J. 
Published: December 2006

AbstractThe applicability of27Al and29Si magic-angle-spinning nuclear magnetic resonance (MASNMR) spectroscopy to the investigation of order-disorder in 1 : 1 dioctahedral layer-silicates was tested.27Al and29Si MASNMR showed the existence of short-range order in all these systems while XRD showed different degrees of long-range order-disorder. Spectra obtained on kaolinite and metakaolin clearly showed the transformation of some octahedral Al in kaolinite to tetrahedral coordination in metakaolin and also showed short-range Al and Si disorder in the latter. This suggests that structural re-arrangement on thermal treatment can be monitored by this technique. These results further suggest that MASNMR can detect short-range order, which is complimentary to the information that XRD provides regarding long-range order.
Nickel-bearing clay minerals: I. Optical spectroscopic study of nickel crystal chemistry
Authors: Manceau A. , Calas G. , Decarreau A. 
Published: December 2006

AbstractNickel crystal chemistry was systematically studied in various phyllosilicates, mainly the natural phases selected from the ‘garnierites’ of the supergene ore deposits of New Caledonia. Minerals which do not usually occur in New Caledonian parageneses were synthesised, as they could represent intermediate phases of genetic importance. In the kerolite-pimelite series, a linear relationship occurred between the ratioI(13,20)/I(02,11)of thehkbands and Ni-content. Diffuse reflectance spectra were used to derive the crystal chemical parameters of Ni. These confirmed its divalent character and its occupation of octahedral sites; the resulting structural distortion was slight and could not be detected in some minerals. There was no optical evidence for Ni atoms in 4-fold coordination. The two main parameters which showed significant variations among the studied phases were site distortion and crystal field stabilization energy (CFSE). Site distortion was at a maximum in trioctahedral smectites and sepiolite. CFSE depended on the mineralogy, crystallinity and chemical composition (Al-content) of the phase. Finally, clay minerals are classified according to the increasing stability of Ni in the octahedral sheet, which has been tentatively related to the geochemical distribution of this element. Secondary minerals are usually enriched vs. primary ones and among them are nepouite and kerolite which exhibit a high CFSE in contrast to sepiolite.
Phyllosilicates and other layer-structured materials in stony meteorites
Authors: Barber D. J. 
Published: December 2006

AbstractCurrent thinking regarding the possible origins and probable evolutionary histories of meteorites is summarized. Selected data concerning the composition, petrology and other characteristics of the CI and CM groups of stony meteorites in which layered minerals principally occur are then presented. Layered compounds, mainly phyllosilicates, are shown to form a major part of the fine-grained matrix of the CI and CM meteorites, which are classified as carbonaceous chondrites. The results of recent investigations of matrix mineralogy are reviewed, with particular emphasis on the findings of electron microscopy. Several forms of Fe-Mg-serpentine have been identified as the principal phyllosilicates. ‘Poorly-characterized phases’ in CM meteorites have proved to be tochilinite and intergrowths of tochilinite with serpentines. The results generally indicate that the phyllosilicates and most other matrix minerals formed by aqueous alteration in the regoliths of the CI and CM parent bodies; but there is isotopic evidence for the incorporation of components and possibly mineral grains which predate the solar nebula. It is concluded that more detailed chemical and mineralogical information about the phyllosilicates and associated minerals will enable useful constraints to be placed on the possible identities of their precursors and the environments in which both they and the matrix minerals formed.
Weathering in a marine clay during postglacial time
Authors: Pederstad K. , Jørgensen P. 
Published: December 2006

AbstractMarine clays of SE Norway lifted above sea-level have been subjected to weathering for 8500 years. As a result of this weathering a major part of the quartz, K-feldspar and plagioclase disappeared in the 0·2–0·6 µm fraction. Trioctahedral illite passed through the sequence: illite → mixed-layer illite-vermiculite → vermiculite → dissolution. This transformation started at a depth of 3 m, and the 2:1 layers dissolved in the upper part of the profile. Chlorite was broken down by weathering into finer particles. As a result, chlorite was first removed from the coarser fractions. Dioctahedral illite in the clay fractions passed through the following transformations in the upper part of the profile: illite → mixed-layer illite-vermiculite → vermiculite → chloritized vermiculite. Weathering models for the size fractions 0·2–0·6 and 0·2–2 µm showed that total amounts of dissolved material from these fractions in the upper part of the profile could be calculated as 55 and 38%, respectively. Dioctahedral 2:1 layers were most resistant to weathering, resulting in 75% dioctahedral phyllosilicates in the 0·2–0·6 µm fraction in the uppermost part of the profile, in contrast to 30% dioctahedral illite in the unweathered sample. This study illustrates the importance of investigating different fractions and not only material finer than 2 µm.
The physical dimensions of fundamental clay particles
Authors: Nadeau P. H. 
Published: December 2006

AbstractThe thickness, length, width, area and perimeter of 575 particles from 16 aqueously dispersed samples of a variety of interstratified clays, smectites and illite have been recorded using TEM techniques. Complete dispersion of the clay material was achieved by saturating the clay with either Na+or Li+, removal of excess ions by dialysis, and isolation of the <0·1 or <0·2µm fraction by centrifugation. The samples have mean maximum dimensions of 1900 to 90 nm and the dispersed system can be considered as colloidal in nature. The mean thickness of the clays is about 1 nm for smectites, corresponding to that of elementary 2:1 silicate layers, from 1·9 to 4·9 nm for the interstratified clays, and 9 nm for illite. From these data the volume, total surface area and other parameters have been calculated and compared with independent determinations of surface area and CEC. The total surface area by TEM, assuming a density of 2·6 g/cm3, varies from ∼675 m2/g for smectites to 86 m2/g for illite, and is inversely proportional to the mean particle thickness. The charge density of monovalent cation exchange sites on the surface of the particles as determined for nine of the samples varies from 0·54 to 1·16 nm2/site. The particle-thickness distribution data can be used to calculate interstratified XRD layer-sequence probabilities and composition parameters, and agree with XRD data for interstratified clay with <60% illite layers. The thickness data also provide a rationale for the interpretation of TEM lattice-fringe images. Relationships between the particle area, length, thickness and volume are shown to be potentially useful in assessing the mechanism(s) of crystal growth of these extremely small phyllosilicate particles.
On the occurrence of Phenacite in Cornwall
Authors: Russell Arthur 
Published: December 2006

The mineral phenacite (beryllium ortho-silicate) has not previously been recorded from the British Isles. The following notes contain an account of its characters and mode of occurrence at five distinct localities in Cornwall. The occurrences are described in the order of their discovery.During the early part of 1905, while examining the Cheesewring Quarry, in company with Mr. F. H. Butler, who on a previous visit had discovered bertrandite at this locality, I paid special attention to the diseovcry, if possible, of any other beryllium minerals. I was fortunate enough, after much searching, to find a specimen showing three small crystals that at once suggested the mineral phenacite ; a surmise which On examination proved correct.
Notes on Cassiterite in the Malay Peninsula
Authors: Scrivenor J. B. 
Published: December 2006

The following notes on some peculiar forms of cassiterite found in the Malay Peninsula will, it is hoped, prove of interest and an addition to our knowledge of the mineral.It is now well known that the most effective method of separating wolframite from eassiterite on a commercial scale is the electromagnetic process, which, in theory, lifts all the wolframite from the ore and lèaves a concentrate of cassiterite. In practice, however, the separation is rarely, if ever, perfect; and it has been possible for the writer to obtain some interesting information bearing on the point, the most valuable being the discovery of a few specimens of cassiterite that may be termed magnetic in that it can be lifted by an electromagnet.
Prehnite from the Lizard district, Cornwall
Authors: Russell Arthur 
Published: December 2006

Hitherto the mineral prehnite has been recorded from one locality only in Cornwall, namely, in the cliffs between Wheal Cock and the Crowns Rock, Botallack, St. Just. It occurs there as pale-green, globular aggregates composed of indistinct, curved crystals, and forms veins traversing a narrow strip of greeustone which has intruded itself through the granite mass; associated minerals are stilbite and axinite.In the summer of 1910 the writer collected several crystallized specimens of this mineral at Pare Bean Cove, Mullion, the locality from which Dr. J.S. Flett and Mr. W. F. P. McLintock obtained the fine crystallized specimens of datolite, recently described by the latter. The prehnite occurs here in two distinct and somewhat unusual types of crystals—tabular and prismatic.
A simple graphic method for determining extinction-angles in sections of biaxial crystals
Authors: Smith H. G. 
Published: December 2006

The relationship between the optic axes and the vibration-directions in a section of a biaxial crystal was enunciated by Biot in 1819, and may be stated as follows : The vibration-directions in any section of a biaxial crystal are given by the bisectors of the angles between the optic axes as projected on the plane of section.Dr. Fletcher and Mr. Harker have elaborated the idea, but there appears to be room for a simpler presentment, more adapted to the needs of students, which does not involve the use of the optical indicatrix or the spherical projection.