bluuebunny/crossref_metadata_2025 huggingface dataset:
Tyrosine Kinase Activity of Discoidin Domain Receptor 1 Is Necessary for Smooth Muscle Cell Migration and Matrix Metalloproteinase Expression
Authors: Hou Guangpei , Vogel Wolfgang F. , Bendeck Michelle P.
Published: July 2002

Smooth muscle cell (SMC) interactions with collagen mediate cell migration during the pathogenesis of atherosclerosis and restenosis. Discoidin domain receptors (DDRs) have been identified as novel collagen receptors. We used aortic SMCs from wild-type and DDR1
−/−
mice to evaluate the function of the DDR1 in regulating migration. DDR1
−/−
SMCs exhibited impaired attachment to and migration toward a type I collagen substrate. Matrix metalloproteinase-2 (MMP-2) and MMP-9 activities were concomitantly reduced in these cells. Transfection of a full-length cDNA for DDR1b rescued these deficits, whereas kinase-dead mutants of DDR1 restored attachment but not migration and MMP production. These results suggest that active DDR1 kinase is a central mediator of SMC migration.
“Postverbal” Subjects and the Mapping Hypothesis
Authors: Longobardi Giuseppe
Published: July 2002

Superficially postverbal subjects of free inversion languages such as, Italian are argued to be able to meet two distinct structural analyses: they may occupy either a VP-internal position, as more traditionally assumed, or a higher (preverbal and, actually, left-peripheral) position, with the remnant of the clause crossing leftward over them by dislocation or focus movement. These are all and only the possibilities expected under recent restrictive theories of phrase structure, like the one advocated by Kayne (1994), and are exactly those empirically realized. Evidence for this conclusion is based primarily on the, (existential/generic) interpretation of bare nouns and overt indefinites and is reinforced by extraction considerations. The whole analysis, based on the interpretation of Romance indefinites, is likely to support some version of Diesing's (1992) Mapping Hypothesis even more strongly than previous types of evidence did, including the original data from Germanic languages.
Complementary Category Learning Systems Identified Using Event-Related Functional MRI
Authors: Aizenstein Howard J. , MacDonald Angus W. , Stenger V. Andrew , Nebes Robert D. , Larson Jeris K. , Ursu Stefan , Carter Cameron S.
Published: July 2002

Event-related fMRI was used to dissociate the neural systems involved in category learning with and without awareness. Ten subjects performed a speeded response category learning task. Functional MR images were acquired during both explicit and implicit learning conditions. Behavioral data showed evidence of learning in both conditions. Functional imaging data showed different activation patterns in implicit and explicit trials. Decreased activation in extrastriate region V3 was found with implicit learning, and increased activation in V3, the medial temporal lobe, and frontal regions were found with explicit learning. These results support the theory that implicit and explicit learning utilize dissociable neural systems. Moreover, in both the implicit and explicit conditions a similar pattern of decreased activation was found in parietal regions. This commonality suggests that these dissociable systems also operate in parallel.
Simple Recurrent Networks Learn Context-Free and Context-Sensitive Languages by Counting
Authors: Rodriguez Paul
Published: July 2002

It has been shown that if a recurrent neural network (RNN) learns to process a regular language, one can extract a finite-state machine (FSM) by treating regions of phase-space as FSM states. However, it has also been shown that one can construct an RNN to implement Turing machines by using RNN dynamics as counters. But how does a network learn languages that require counting? Rodriguez, Wiles, and Elman (1999) showed that a simple recurrent network (SRN) can learn to process a simple context-free language (CFL) by counting up and down. This article extends that to show a range of language tasks in which an SRN develops solutions that not only count but also copy and store counting information. In one case, the network stores information like an explicit storage mechanism. In other cases, the network stores information more indirectly in trajectories that are sensitive to slight displacements that depend on context. In this sense, an SRN can learn analog computation as a set of interdependent counters. This demonstrates how SRNs may be an alternative psychological model of language or sequence processing.
Asymmetric Dynamics in Optimal Variance Adaptation
Authors: DeWeese Michael , Zador Anthony
Published: July 2002

It has long been recognized that sensory systems adapt to their inputs. Here we formulate the problem of optimal variance estimation for a broad class of nonstationary signals. We show that under weak assumptions, the Bayesian optimal causal variance estimate shows asymmetric dynamics: an abrupt increase in variance is more readily detectable than an abrupt decrease. By contrast, optimal adaptation to the mean displays symmetric dynamics when the variance is held fixed. After providing several empirical examples and a simple intuitive argument for our main result, we prove that optimal adaptation is asymmetrical in a broad class of model environments. This observation makes specific and falsifiable predictions about the time course of adaptation in neurons probed with certain stimulus ensembles.
Adaptive Neural Coding Dependent on the Time-Varying Statistics of the Somatic Input Current
Authors: Shin Jonghan , Koch Christof , Douglas Rodney
Published: July 2002

It is generally assumed that nerve cells optimize their performance to reflect the statistics of their input. Electronic circuit analogs of neurons require similar methods of self-optimization for stable and autonomous operation. We here describe and demonstrate a biologically plausible adaptive algorithm that enables a neuron to adapt the current threshold and the slope (or gain) of its current-frequency relationship to match the mean (or dc offset) and variance (or dynamic range or contrast) of the time-varying somatic input current. The adaptation algorithm estimates the somatic current signal from the spike train by way of the intracellular somatic calcium concentration, thereby continuously adjusting the neuronś firing dynamics. This principle is shown to work in an analog VLSI-designed silicon neuron.
Improving the Convergence of the Backpropagation Algorithm Using Learning Rate Adaptation Methods
Authors: Magoulas G. D. , Vrahatis M. N. , Androulakis G. S.
Published: July 2002

This article focuses on gradient-based backpropagation algorithms that use either a common adaptive learning rate for all weights or an individual adaptive learning rate for each weight and apply the Goldstein/Armijo line search. The learning-rate adaptation is based on descent techniques and estimates of the local Lipschitz constant that are obtained without additional error function and gradient evaluations. The proposed algorithms improve the backpropagation training in terms of both convergence rate and convergence characteristics, such as stable learning and robustness to oscillations. Simulations are conducted to compare and evaluate the convergence behavior of these gradient-based training algorithms with several popular training methods.
Out of the Fringe? Out of the Closet: Latina/Latino Theatre and Performance in the 1990s
Authors: Marrero María Teresa
Published: July 2002

A different take on Latina/o performance, from someone who lives not in LA or NY, but in Texas. Marrero traces the “possibilities of representation” for Latinas/os from the days of El Teatro Campesino to now.
Building a Bridge between Different Scientific Communities: On Sheridan's Eclectic Ontology of Presence
Authors: Mantovani Giuseppe , Riva Giuseppe
Published: July 2002

Sheridan's recent paper (1999) on presence is particularly relevant to research on virtual environments (VEs). Sheridan's “eclectic” ontology and his “model of evaluation” proposed as a bridge to close the gap between different positions are discussed. A modification of the evaluation model is suggested to make it apt to provide common ground for different perspectives. VEs are boundary objects that interest various research communities with different worldviews, and cooperation among these communities is necessary if VEs are to become tools for communication and coworking.
Building Blocks, Cohort Genetic Algorithms, and Hyperplane-Defined Functions
Authors: Holland John H.
Published: July 2002

Building blocks are a ubiquitous feature at all levels of human understanding, from perception through science and innovation. Genetic algorithms are designed to exploit this prevalence. A new, more robust class of genetic algorithms, cohort genetic algorithms (cGA's), provides substantial advantages in exploring search spaces for building blocks while exploiting building blocks already found. To test these capabilities, a new, general class of test functions, the hyperplane-defined functions (hdf's), has been designed. Hdf's offer the means of tracing the origin of each advance in performance; at the same time hdf's are resistant to reverse engineering, so that algorithms cannot be designed to take advantage of the characteristics of particular examples.
Competing Political Visions: WTO Governance and Green Politics
Authors: Weber Martin
Published: July 2002

It has long been recognized that environmental concerns transcend borders. As a result, they pose problems, the solution of which requires new forms of cooperation beyond the conception of international politics as structured by the interests of nation-states. Today, such cooperation has to be sought in the context of emerging global governance. This article traces differing conceptions of the political nature of global governance in the context of the debate over the trade-environment link. This link is being constructed for the global level at the WTO, and contested either with reformist intent or in more radical terms by environ-mentalists. Following an exposition of the genesis of the trade-environment link and of the different conceptions of it held by proponents of the free trade agenda and environmentalists, the article concludes by arguing for a more sustained appreciation of the issues raised by the radical critics.
What Could a World Environmental Organization Do?
Authors: Whalley John
Published: July 2002

This article evaluates the case for a new World Environmental Organization. It suggests that the main purpose of such an institution could be to accomplish the internalization of global environmental externalities which, for a variety of reasons, has not been achieved to any significant degree in recent decades. This stands in contrast to recent proposals that call for a mere strengthening of existing global arrangements. The benefits of this approach, as well as some of its problems, such as ambiguous property rights, are discussed.
PUBLIC POLICY AND ISLAMIC LAW: THE MODERN DHIMMĪ IN CONTEMPORARY EGYPTIAN FAMILY LAW
Authors: Berger Maurits
Published: July 2002

Egyptian law has maintained the Islamic system of interreligious law in which the Muslim, Christian and Jewish communities are governed by their own courts and their own laws. In the course of the twentieth century, however, these separate courts were abolished and the application of non-Muslim laws was restricted to matters of marriage and divorce, and then only if the non-Muslim spouses share the rite and sect of the same religion. In all other cases Islamic law applies. In addition, non-Muslim laws may not be applied if they violate Egyptian "public policy", a European concept which refers to the fundamentals of a national legal order. Egyptian public policy can be defined as those principles which are essential in Islamic law. In this article I analyse the status of the non-Muslim Egyptian in contemporary personal status law, based on Egyptian case law and legal literature. The concept of public policy plays a key role in understanding the mechanics of interreligious law in Egypt. I will argue that public policy serves as a legal barometer of the coexistence between Muslim and non-Muslim communities in Egypt.
Reproductive and feeding ecology of the amphisbaenian Anops kingii in east-central Argentina
Authors: Vega Laura
Published: July 2002

The reproductive and feeding ecology of Anops kingii was studied at the pampas mountain range of Argentina. Reproduction occurred from late winter (July) to early summer (December). Mean clutch size, based on the number of oviductal eggs, ranged from 2 to 4 eggs (x¯= 3), whereas mean clutch size based on the number of yolked follicles was 2.2 eggs. Adult females were significantly larger than males and all male individuals had conspicuous precloacal pores, whereas all females lacked them. Diet was not diverse and consisted mainly of coleopteran larvae. Foraging activity decreased during the coldest months of the year. Individuals were found under large rocks predominantly during winter and spring. This seasonal pattern of activity near the surface would seem to be related more to thermoregulatory than to trophic requirements.
A NEW SPECIES OF TORTANUS (COPEPODA, CALANOIDA) FROM TAIWAN
Authors: Chen Qing-Chao , Hwang Jiang-Shiou
Published: July 2002

A new species, Tortanus taiwanicus of the family Tortanidae (Copepoda, Calanoida), is described and illustrated from zooplankton collected in the coastal waters of Hualien, Taiwan. Tortanus (Atortus) taiwanicus may be distinguished from other species of the subgenus by the thoracic somites 4 and 5 being fused and protruding middorsally in the female, and by urosomal somite 2 of the male being furnished on the right side with postero-lateral and postero-ventral processes of unequal size, as well as by the shape of the male's fifth legs. This species may be endemic to Taiwan. Une nouvelle espece, Tortanus taiwanicus, de la famille des Tortanidae (Copepoda, Calanoida) est decrite et illustree du zooplancton des eaux cotieres de Hualien, Taiwan. Tortanus (Atortus) taiwanicus peut etre distinguee des autres especes du sous-genre par les somites thoraciques 4 et 5 qui sont fusionnes et font saillie medio-dorsalement chez la femelle et par le somite 2 de l'urosome du male qui est pourvu du cote droit de processus postero-lateral et postero-ventral de taille inegale, ainsi que par la forme des cinquiemes pattes de ce dernier. Cette espece peut etre endemique de Taiwan.
ON SOME INLAND CRUSTACEA AND THEIR HABITATS OF MONA ISLAND IN THE NORTHERN CARIBBEAN REGION
Authors: Wier Andrew , Smith Douglas
Published: July 2002

A recent extensive survey of Mona Island, an unihabited island between Puerto Rico and Hispaniola, has revealed the presence of four inland crustacean species previously unreported from the island, a new genus and species of terrestrial amphipod, Cariborchestia xerophila, a clam shrimp in the genus Eulimnadia, a terrestrial isopod, Venezillo culebrae, and a subterranean shrimp, Macrobrachium faustinum var. A few of these species are briefly discussed with respect to their systematics and their habitats. The three taxa other than the new amphipod are taxonomically poorly understood. The habitats all species occur in are small, isolated, and ephemeral to varying degrees and very susceptable to alteration. Such habitats are now rare or have been destroyed in larger developed islands of the region. Protection of these remaining habitats is neccessary to allow study of inhabitants and their role in the ecology of limestone islands. Une etude extensive recente de Mona Island, une ole inhabitee entre Puerto Rico et Hispaniola, a revele la presence de quatre especes auparavant non signalees des eaux interieures de cette ole, un genre et une espece nouveaux d'amphipode terrestre, Cariborchestia xerophila, un branchiopode Spinicaudata du genre Eulimnadia, un isopode terrestre, Venezillo culebrae, et une crevette souterraine, Macrobrachium faustinum var. Quelques-unes de ces especes sont discutees brievement quant a leur systematique et leurs habitats. Les trois taxa autres que l'amphipode nouveau sont peu connus sur le plan systematique. Les habitats qui abritent ces especes sont petits, isoles et ephemeres a des degres divers, et susceptibles d'etre exposes a des modifications. La protection de ces habitats survivants est necessaire pour permettre l'etude des organismes qui y vivent et leur role dans l'ecologie des oles calcaires.
ORIGIN AND DIVERSITY OF CAINOZOIC DEEP-SEA OSTRACODA
Authors: Harten Dick Van
Published: July 2002

Recent developments in deep-sea ostracodology are reviewed with special reference to diversity and evolution. Origin and composition of modern deep-sea ostracod faunas are discussed as are some relationships with palaeoceanographic events. Les developpements actuels dans l'ostracodologie de la mer profonde sont resumes en se referant specifiquement a la diversite et l'evolution. L'origine et la composition des faunes d'ostracodes des mers profondes sont discutes ainsi que quelques connections avec des evenements paleoceanographiques.
THE GROUNDWATER AMPHIPOD BOGIDIELLA TURCICA N. SP. AND OTHER BOGIDIELLIDS (MALACOSTRACA, AMPHIPODA) IN SOUTHWEST TURKEY
Authors: Vonk  , Notenboom  , Seveso
Published: July 2002

Bogidiella turcica n. sp. and the male of Bogidiella minotaurus Ruffo & Schiecke, 1976 are described from, respectively, a brackish littoral submarine spring and the interstitial of a river mouth in Turkey. Bogidiella longiflagellum S. Karaman, 1959 was found in 13 inland wells and riverbeds in the region between Izmir and Antalya (Anatolia). Morphological variation within and between three populations of B. longiflagellum from distant localities has been measured by comparing 8 specimens per station.
Bogidiella turcica sp. nov. et le male de Bogidiella minotaurus Ruffo & Schiecke, 1976 sont decrits de, respectivement, une source littorale sous-marine saumatre et de l'interstitiel de l'embouchure d'une riviere en Turquie. Bogidiella longiflagellum S. Karaman, 1959 a ete trouve en 13 puits et lits de riviere de l'interieur, entre Izmir et Antalya (Anatolie). La variation morphologique dans et entre 3 populations de B. longiflagellum a ete mesuree par comparaison de 8 specimens par station.
A new genus of Carnoyidae (Nematoda: Rhigonematida) with descriptions of Cattiena trachelomegali gen. n., sp. n. and C. trigoniuli gen. n., sp. n., parasites of Spirobolida (Diplopoda) from Vietnam
Authors: Spiridonov Sergei , Hunt David
Published: July 2002

Cattiena gen. n., a new genus from the Carnoyidae, is described from the posterior gut of two genera of spirobolid diplopods from Vietnam. The new genus is characterised by: presence of eight somatic spine rows in the cervical region of both male and female, the four sublateral spine rows being better developed; presence of six cuticularised plates around the female oral opening; extremely posterior vulva; two anteriorly directed ovaries; isomorphic and isometric spicules; boat-shaped gubernaculum of similar form to the spicules; gubernaculum with a dorsal hole; well developed, smooth cephalic cap in the male and 15 copulatory papillae with three pairs located lateral, sublateral or subdorsal. The new genus has morphological affinities with Raonema Kloss, 1965, a poorly known genus from India, but is easily differentiated by the extremely posterior vulva and the presence of spine rows in the male. Two new species are described in the genus: the type, C. trachelomegali gen. n., sp. n. from Trachelomegalus sp. and C. trigoniuli gen. n., sp. n. from Trigoniulus sp. The two species differ primarily in the position of the vulva (consistently more anterior in the latter species), degree of development of the vulval flap, body length, tail length and in the relative development of the somatic spine rows.
Clay mineral distribution in the Devonian-Carboniferous sandstones of the Clair Field, west of Shetland, and its significance for reservoir quality
Authors: Pay M. D. , Astin T. R. , Parker A.
Published: July 2002

The Devonian-Carboniferous reservoir of the Clair Field contains a complex and variably abundant clay mineral assemblage. An abrupt vertical change in clay mineralogy has been observed in both wells studied (UKCS 206/8-7 and 206/8-8) from being rich in Mg-chlorite, chlorite- smectite (including dioctahedral corrensite), illite, illite-smectite and Fe-chlorite, to being smectite- rich. This change broadly coincides with the unconformable boundary between the Lower Clair Group and Upper Clair Group of the reservoir which possibly defines the Devonian-Carboniferous boundary. The clay minerals present reflect interaction between: (1) tectonic stability and climate that controlled the detrital composition of the sediment; (2) the pore-waters that developed; and (3) the result of diagenetic modification.

Matrix porosity and permeability is severely restricted where the pore-lining clays are abundant (>15%) and where the clays bridge or fill pores. The type of clay mineral species appears to have a minor influence on reservoir quality, although they may be extremely important during production. The best reservoir quality occurs in mature aeolian sediments with a thin illite and illite-smectite clay coating.
Different rates of smectite illitization in mudstones and sandstones from the Niigata Basin, Japan
Authors: Niu B. , Ishida H.
Published: July 2002

The different rates of smectite illitization have been investigated in interbedded sandstone and mudstone samples from the Neogene to Lower Pleistocene stratigraphy of the Niigata sedimentary basin. For samples of approximately the same age and under the same temperature and pressure conditions, the analytical results of XRD and EDS show that differences in the transformation from R = 1 I-S to R≥3 I-S at a temperature of ~30–40°C and 1000 m in depth are determined by the initial smectite composition and the relative ion concentration of pore-fluid in the sedimentary rock system. The ordered I-S and illite in the mudstone have inherited compositional characteristics from the initial detrital smectite and illite. In the sandstone, the I-S composition was changed by interaction with pore-fluids and by precipitation and crystal growth during diagenesis.
Swelling pressure and microstructure of an activated swelling clay with temperature
Authors: Tessier D. , Dardaine M. , Beaumont A. , Jaunet A. M.
Published: July 2002

Clay from Fourges has been selected by the Commissariat à l'Energie Atomique as a support in radioactive waste disposal studies. This material was activated by adding Na2CO3, then compacted at 60 MPa. Subsequently, its swelling behaviour was monitored at 90°C and 145°C for 330 days and at the end of this period the samples were examined by transmission electron microscopy (TEM). For this, they were embedded in a resin then sectioned with an ultramicrotome for mineralogical and chemical analyses. The initial material is essentially composed of kaolinite and smectite. Addition of Na2CO3 at room temperature induces a replacement of Ca ions by Na ions and the precipitation of finely divided carbonates on the surface of the constituents. At the end of 330 days at 90°C under a hydraulic pressure of 1 MPa, the initial particles combine and the material exerts a swelling pressure of 20 MPa. A complete reorganisation of the clay crystallites is observed without significant dissolution of the solid phases. After the same time at 145°C under a hydraulic pressure of 10 MPa, in a basic medium, the combined conditions are such that a high proportion of the clay is dissolved with formation of amorphous aluminosilicates correlated with a marked drop in the swelling pressure to 5 MPa. This work establishes the advantages of following the macroscopic properties in parallel with the microstructure variations for understanding the changes in the properties of clays.
Kinetic study by controlled-transformation rate thermal analysis of the dehydroxylation of kaolinite
Authors: Dion P. , Alcover J.-F. , Bergaya F. , Ortega A. , Llewellyn P. L. , Rouquerol F.
Published: July 2002

Although the kinetics of the dehydroxylation of kaolinite have been widely studied, there is no definitive explanation of its mechanism due to its dependence on a variety of parameters. In this study, the dehydroxylation of kaolinite has been studied using controlled-transformation rate thermal analysis (CRTA), allowing precise control of the reaction rate, and thus of both the temperature and pressure above the sample. Modelling of the experimental results obtained by CRTA as well as those from TEM and MAS-NMR show that two elementary processes (diffusion and firstorder) can occur in competition. At the start of the decomposition the diffusion mechanism is predominant, but as the reaction progresses, the first-order mechanism prevails. It would seem that the importance of each process depends, in particular, on the presence of defects as well as on the local vapour pressure.
Clay mineralogy at Rothamsted: 1934—1988
Authors: Loveland P. J. , Wood I. G. , Weir A. H.
Published: July 2002

Soil clay mineralogy at Rothamsted began in the early 1930s, and quickly focused on technique, swelling minerals, micas and sorption phenomena. By the mid-1940s interest had extended to the formation and spatial distribution of soil clays with the move of the Soil Survey of England and Wales to Rothamsted. These themes continued for the next 40 years. Considerable contributions were made to crystal chemistry and structure determinations, and the relationship of these to the sorption and desorption of water and organic molecules, and the behaviour of soil K. The pattern of soil clay mineralogy was determined for large parts of England and Wales, and absorbed into soil mapping. The work on X-ray diffraction appeared in the Mineralogical Society Monographs on this subject. These, and the Monograph on Clay Chemistry, which reached their final form in the 1980s, are the lasting monuments to soil clay mineralogical research at Rothamsted.
Distribution of manganese in synthetic goethite
Authors: Gasser U. G. , Nüesch R. , Singer M. J. , Jeanroy E.
Published: July 2002

A series of Mn-goethites was synthesized at highly alkaline conditions. The samples were aged for 15 days at a final [KOH] of 0.3 M. Products were washed free from non-goethite phases using 3 M H2SO4. The bulk mineralogy of the samples was determined by X-ray diffraction and verified on selected individual crystals by electron diffraction. The samples had a relatively low magnetic susceptibility (300≤MS≤400×10-9 m3/kg). As revealed by total acid dissolution, the Mn mole fraction XMn ranged from zero to 0.125. Five samples (XMn: 0.025, 0.050, 0.077, 0.099, 0.125) were selected to investigate the variability of the XMn value in single goethite needles (crystals) by analytical electron microscopy (AEM) using rastered and spot analyses. Linear regressions of both as a function of total Mn yielded unit slopes and zero intercepts, indicating that acid dissolution gave the same results as AEM. Spot AEM, however, revealed significant variation of Mn distribution within individual crystals which argues in favour of Mn zoning in goethite. Inhomogeneous transformation of ferrihydrite to goethite may partly explain the Mn zoning.
Gahnite in the ∼3.75 Ga Isua Greens tone Belt, West Greenland
Authors: Appel P. W. U.
Published: July 2002

The Zn-spinel gahnite has been discovered in the ∼3.75 Ga Isua Greenstone Belt, West Greenland. It is light blue-green to colourless in hand specimen and colourless in thin section as opposed to most other gahnites which are dark green to brown. The gahnites from Isua have very low Fe and Mg contents, and their compositions are thus close to the endmember gahnite. The gahnite was formed, during metamorphism, from sphalerite, in the absence of Fe-rich sulphides.
Mineral transformations
Authors: Redfern S. A. T.
Published: July 2002

One of the major goals of mineral science is attaining an understanding of the atomic-scale mechanisms and dynamics of minerals that control their structural transformations as a function of pressure, temperature or chemical composition in the natural environment. Examples of research programmes that sail under this heading include those devoted to observing and modelling the role of phase transformations on controlling mineral microstructures, ordering, elasticity, transport, premelting and exsolution. The geological relevance and intrinsic importance (as being representative of specific properties or thermodynamic/ kinetic behaviour) of mineral transformations has long been appreciated. It prompted the recent initiation of a network on Mineral Transformations (http://www.esc.cam.ac.uk/mintrans/) under the European Union TMR Programme. In response to this development, a special session on Mineral Transformations was held at the EUG congress in Strasbourg last year.
Microtexture and water content of alkali feldspar by Fourier-transform infrared microspectroscopy
Authors: Nakano Satoshi , Makino K. , Eriguchi T.
Published: July 2002

Alkali feldspar (Or64.5Ab34.8An0.6) in a granite pegmatite from Hanazono, Kosei Town, Shiga Prefecture, southwest Japan, consists of two types of regions observable with the naked eye: one is colourless and transparent, and the other is pale pink and opaque. The colourless regions are clear, cryptoperthitic and almost free of micropores, and the pale pink regions are turbid, vein microperthitic and with many micropores visible under a microscope. The latter regions may have been changed from the former by the catalytic action of water. Integrated absorbance values were calculated for both types of regions from Fourier-transform infrared microspectra in the range 2500–4000 cm−1. These values were used as semi-quantitative parameters of water contents. The turbid regions are much more enriched in water compared to the clear regions. The chemical states of water in both regions were also evaluated. Water in the turbid regions is estimated to be present mainly as H2O inclusions in micropores and to be present to a lesser extent as structural OH groups. A small amount of water in the clear regions may be present as structural OH groups. The water distribution in the feldspar records the cooling history of hydrothermal reactions causing the coarsening of cryptoperthites to microperthites.
The origin of igneous layering in the Nunarssuit syenite, South Greenland
Authors: Hodson M. E.
Published: July 2002

The rhythmic modal layering in the Nunarssuit syenite has a vertical extent of >150 m and a lateral extent of >15 km. Individual layers average 20 cm thick and grade from a relatively melanocratic base into more leucocratic syenite over a distance of up to 5 cm. The major cumulus phases are alkali feldspar, ferro-salite/hedenbergite and fayalite. Two basic stratigraphic cycles have been identified in which faint modal layering becomes more pronounced up section, each cycle terminating in a thick melanocratic zone. Slumps, slump breccias, troughs, micro-rhythmic layering and one occurrence of crossed layers were observed.

Qualitative grain size analysis indicates no size sorting in the layers. Preliminary application of crystal size distribution theory to ferro-salite/hedenbergite and fayalite from the bases of individual layers gives results which may be interpreted as indicating a relative lack of coarse grains. If the layers were deposited from density currents it would be expected that the coarsest grains would be deposited close to the source of the currents. There is no evidence in the majority of the syenite that the cumulus pile underwent compaction during crystallization.

There was little, or no, primary chemical variation across individual layers. Whole-rock compositions and the ferro-salite/hedenbergite, fayalite, biotite and amphibole present in the syenites show a slight, but statistically significant, increase in the ratio Mg/(Mg+Fetotal), from the base up to the top of the layered succession.

A model is suggested in which successive magma layers become more ferroan towards the top of the chamber. Cooling is concentrated at the top of the chamber and layers of magma crystallize sequentially, the uppermost, ferroan layers first. As layers of magma cool and crystallize they sink, as crystal-melt plumes, to the bottom of the chamber where they source density currents from which layers are deposited.
Hyalotekite, (Ba,Pb,K)4(Ca,Y)2Si8(B,Be)2(Si,B)2O28F, a tectosilicate related to scapolite: new structure refinement, phase transitions and a short-range ordered 3bsuperstructure
Authors: Christy A. G. , Grew E. S. , Mayo S. C. , Yates M. G. , Belakovskiy D. I.
Published: July 2002

Hyalotekite, a framework silicate of composition (Ba,Pb,K)4(Ca,Y)2Si8(B,Be)2(Si,B)28F, is found in relatively high-temperature (⩾ 500°C) Mn skarns at Långban, Sweden, and peralkaline pegmatites at Dara-i-Pioz, Tajikistan. A new paragenesis at Dara-i-Pioz is pegmatite consisting of the Ba borosilicates leucosphenite and tienshanite, as well as caesium kupletskite, aegirine, pyrochlore, microcline and quartz. Hyalotekite has been partially replaced by barylite and danburite. This hyalotekite contains 1.29–1.78 wt.% Y2O3, equivalent to 0.172–0.238 Y pfu or 8–11% Y on the Ca site; its Pb/(Pb+Ba) ratio ranges 0.36–0.44. Electron microprobe F contents of Långban and Dara-i-Pioz hyalotekite range 1.04–1.45 wt.%, consistent with full occupancy of the F site. A new refinement of the structure factor data used in the original structural determination of a Långban hyalotekite resulted in a structural formula, (Pbl.96Bal.86K0.18)Ca2(B1.76Be0.24)(Sil.56B0.44)Si8O28F, consistent with chemical data and all cations with positive-definite thermal parameters, although with a slight excess of positive charge (+57.14 as opposed to the ideal +57.00). An unusual feature of the hyalotekite framework is that 4 of 28 oxygens are non-bridging; by merging these 4 oxygens into two, the framework topology of scapolite is obtained. The triclinic symmetry of hyalotekite observed at room temperature is obtained from a hypothetical tetragonal parent structure via a sequence of displacive phase transitions. Some of these transitions are associated with cation ordering, either Pb–Ba ordering in the large cation sites, or B–Be and Si–B ordering on tetrahedral sites. Others are largely displacive but affect the coordination of the large cations (Pb, Ba, K, Ca). High-resolution electron microscopy suggests that the undulatory extinction characteristic of hyalotekite is due to a fine mosaic microstructure. This suggests that at least one of these transitions occurs in nature during cooling, and that it is first order with a large volume change. A diffuse superstructure observed by electron diffraction implies the existence of a further stage of short-range cation ordering which probably involves both (Pb,K)–Ba and (BeSi,BB)–BSi.
Two contrasting mineral assemblages in the Meliata blueschists, Western
Carpathians, Slovakia
Authors: Faryad S. W. , Hoinkes G.
Published: July 2002

Low-grade metamorphic rocks from the Meliata unit (Western Carpathians) are
characterized by the presence of typical blueschist-facies minerals. In
metabasalt, an early low-pressure assemblage (<0.5 GPa at 350°C characterized
by muscovite and zoisite, is followed by high-pressure glaucophane, phengite,
Na-pyroxene, chlorite, clinozoisite and Al-poor titanite, indicating pressures of
>1.2 GPa at 450°C Na-pyroxene shows strong compositional variations between the
end-members Jd4–70, Aeg10–49 and
Q17–49, respectively. Phengite has high Si content of 3.5
a.p.f.u. The zoisite with Al2Fe
(100[Fetot/(−2+Altot+Fetot)])
= 3–5%, is rimmed by clinozoisite, with a maximum of 75%
Al2Fe, as well as being enclosed by glaucophane. The
occurrence of clinozoisite, rimming zoisite, suggests that the transformation of
orthorhombic to monoclinic epidote depends not only on the temperature but also on
the pressure. In the studied metabasalt, retrograde phases reflecting
greenschist-facies conditions are albite and chlorite. Some neighbouring
metabasites may additionally contain actinolite and biotite.
Aluminium mass transfer and diffusion in water at 400–550°C, 2 kbar in the
K2O–Al2O3–SiO2–H2O
system driven by a thermal gradient or by a variation of temperature with
time
Authors: Vidal O. , Durin L.
Published: July 2002

Tube-in-tube experiments involving a time-dependent variation of temperature
or a strong thermal gradient were conducted in order to decipher the transport and
transfer of Al in a closed medium along with dilute water. Results show that the
solubility and the transport of Al are controlled by the alkali availability.
Starting from a mixture of kyanite + quartz + muscovite at the hot end of a
thermal gradient, Al is transported toward the cold end in the form of a complex
with an Al/K stoichiometry close to unity. Since more Al than alkali are released
by the dissolution of muscovite, an Al-rich phase (kyanite) forms in the vicinity
of the starting minerals undergoing dissolution, although Al is mobile in the
system. Then, the variation of the solubility of the Al-K complex with temperature
leads to the formation of muscovite (+quartz) at the cold end of the thermal
gradient. A quantitative interpretation of the experimental results was carried
out using data from the literature on Al speciation in dilute water. Extrapolation
of the laboratory data to natural rocks suggests that the diffusion of Al is an
efficient transport process under medium-grade, low- to medium-pressure
conditions. Therefore, mass-transfer estimates based on mass-balance analyses
postulating a fixed Al reference frame should be considered with caution. Also the
high fluid to rock ratio calculated from the amount of aluminosilicates occurring
in veins of medium-grade metapelites is questionable because such calculations
neglect the importance of the transport of Al by diffusion.
Itoigawaite, a new mineral, the Sr analogue of lawsonite, in jadeitite from
the Itoigawa-Ohmi district, central Japan
Authors: Miyajima H. , Matsubara S. , Miyawaki R. , Ito K.
Published: July 2002

Itoigawaite,
SrAl2Si2O7(OH)2·H2O,
is a new member of the lawsonite group found in the Itoigawa-Ohmi district,
central Japan. It is orthorhombic, Cmcm,
a = 6.031(2), b =
8.945(2), c = 13.219(4) Å, Z = 4. The strongest lines
in the X-ray powder diffraction pattern are 4.68 (s) (111), 4.26 (vs) (021), 3.31
(vs) (113), 2.75 (vs) (114, 202), 2.68 (vvs) (130), 2.63 (s) (131), 2.50 (s) (220,
203, 132), 2.45 (s) (221). Electron microprobe analysis gave
SiO2 32.98, TiO2 0.87,
Al2O3 27.67,
Fe2O3 0.39, MgO 0.27, CaO 0.45, SrO
27.71, H2O (diff.) 9.66, total 100.00 wt.%, corresponding to
(Sr0.97Ca0.03Mg0.02)Σ1.02
(Al1.97Ti0.04Fe0.02)Σ2.03Si1.99H3.89O10
on the basis of O = 10. It is transparent, blue in colour with vitreous lustre.
The streak is white and the cleavage good in one direction. The hardness is 5–5.5.
The calculated density is 3.3 g cm−3. It is colourless in
thin section and optically biaxial positive with α = 1.664 (2), β = 1.674 (2), γ =
1.688 (2) and 2V(calc.) = 81°. It occurs in a thin veinlet cutting a
lavender-coloured Ti-bearing jadeitite. The veinlet includes irregularly-shaped
aggregates composed of minute tabular crystals of itoigawaite up to 50 µm across
and minute jadeite crystals with interstitial natrolite aggregates. Itoigawaite is
considered to be crystallized from fluid during later stage activity of
high-P/T metamorphism. The name is for the
locality.
Highly heterogeneous nature of δ-aminolevulinate dehydratase (ALAD) deficiencies in ALAD porphyria
Authors: Maruno Motoyoshi , Furuyama Kazumichi , Akagi Reiko , Horie Yutaka , Meguro Kuniaki , Garbaczewski Luba , Chiorazzi Nicholas , Doss Manfred O. , Hassoun Alexandre , Mercelis Rudolf , Verstraeten Luc , Harper Pauline , Floderus Ylva , Thunell Stig , Sassa Shigeru
Published: July 2002

The properties of 9 δ-aminolevulinate dehydratase (ALAD) mutants from patients with ALAD porphyria (ADP) were examined by bacterial expression of their complementary DNAs and by enzymologic and immunologic assays. ALADs were expressed as glutathione-S-transferase (GST) fusion proteins inEscherichia coli and purified by glutathione-affinity column chromatography. The GST-ALAD fusion proteins were recognized by anti-ALAD antibodies and were enzymatically active as ALAD. The enzymatic activities of 3 ALAD mutants, K59N, A274T, and V153M, were 69.9%, 19.3%, and 41.0% of that of the wild-type ALAD, respectively, whereas 6 mutants, G133R, K59N/G133R, F12L, R240W, V275M, and delTC, showed little activity (< 8%). These variations generally reflect the phenotype of ALAD in vivo in patients with ADP and indicate that GST-ALAD fusion protein is indeed useful for predicting of the phenotype of ALAD mutants. The location of F12L mutation in the enzyme's molecular structure indicates that its disturbance of the quaternary contact of the ALAD dimer appears to have a significant influence on the enzymatic activity. Mouse monoclonal antibodies to human ALAD were developed that specifically recognized a carboxy terminal portion of ALAD, or other regions in the enzyme. This study represents the first complete analysis of 9 mutants of ALAD identified in ADP and indicates the highly heterogeneous nature of mutations in this disorder.
Inhibition of Plasmodium yoelii blood-stage malaria by interferon α through the inhibition of the production of its target cell, the reticulocyte
Authors: Vigário Ana Margarida , Belnoue Elodie , Cumano Ana , Marussig Myriam , Miltgen François , Landau Irene , Mazier Dominique , Gresser Ion , Rénia Laurent
Published: July 2002

The effect of a recombinant hybrid human interferon α (IFN-α) (which cross-reacts with murine cells) on C57BL/6 mice infected with Plasmodium yoelii sporozoites or parasitized erythrocytes was determined. IFN-α did not inhibit the development of the parasite in the liver, but it did reduce the blood parasite load and the hepatosplenomegaly induced by the infection in mice injected with blood-stage parasites. The extent of anemia in IFN-α–treated and control mice was similar, despite the lower parasite load in the IFN-α–treated mice. The reduced blood parasite load in IFN-α–treated mice was associated with reduced erythropoiesis and reticulocytosis. As reticulocytes are the preferred target cells for the strain of P yoelii used (P yoelii yoelii 265 BY), it was postulated that the inhibition of reticulocytosis in IFN-α–treated mice was causally related to the observed decreased blood parasite load. This was supported by the finding that IFN-α inhibited a different strain ofP yoelii (17X clone A), which also displays a tropism for reticulocytes, but not a line of Plasmodium vinckei petteri, which infects only mature red blood cells. As human malaria species also display different tropism for reticulocytes, these findings could be relevant for people coinfected with multiple Plasmodium species or strains or coinfected with Plasmodium and virus.
SHIP's C-terminus is essential for its hydrolysis of PIP3 and inhibition of mast cell degranulation
Authors: Damen Jacqueline E. , Ware Mark D. , Kalesnikoff Janet , Hughes Michael R. , Krystal Gerald
Published: July 2002

The SH2-containing inositol-5′-phosphatase, SHIP, restrains bone marrow–derived mast cell (BMMC) degranulation, at least in part, by hydrolyzing phosphatidylinositol (PI)-3-kinase generated PI-3,4,5-P3 (PIP3) to PI-3,4-P2. To determine which domains within SHIP influence its ability to hydrolyze PIP3, bone marrow from SHIP−/− mice was retrovirally infected with various SHIP constructs. Introduction of wild-type SHIP into SHIP−/− BMMCs reverted the Steel factor (SF)-induced increases in PIP3, calcium entry, and degranulation to those observed in SHIP+/+ BMMCs. A 5′-phosphatase dead SHIP, however, could not revert the SHIP−/− response, whereas a SHIP mutant in which the 2 NPXY motifs were converted to NPXFs (2NPXF) could partially revert the SHIP−/− response. SF stimulation of BMMCs expressing the 2NPXF, which could not bind Shc, led to the same level of mitogen-activated protein kinase (MAPK) phosphorylation as that seen in BMMCs expressing the other constructs. Surprisingly, C-terminally truncated forms of SHIP, lacking different amounts of the proline rich C-terminus, could not revert the SHIP−/− response at all. These results suggest that the C-terminus plays a critical role in enabling SHIP to hydrolyze PIP3 and inhibit BMMC degranulation.
In vitro cytotoxic effects of a tyrosine kinase inhibitor STI571 in combination with commonly used antileukemic agents
Authors: Kano Yasuhiko , Akutsu Miyuki , Tsunoda Saburo , Mano Hiroyuki , Sato Yuko , Honma Yoshio , Furukawa Yusuke
Published: July 2002

The BCR/ABL tyrosine kinase has been implicated in the pathogenesis of chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). STI571 is a novel anticancer agent that selectively inhibits the BCR/ABL tyrosine kinase. The cytotoxic effects of STI571 were studied in combination with antileukemic agents against Ph+leukemia cell lines, KU812, K-562, TCC-S, and TCC-Y. The cells were exposed to STI571 and to other agents simultaneously for 5 or 7 days. Cell growth inhibition was determined by MTT assay. The cytotoxic effects in combinations at the inhibitory concentration of 80% level were evaluated by the isobologram. STI571 produced synergistic effects with recombinant and natural α-interferons in 2 of 3 and 3 of 3 cell lines, respectively. STI571 produced additive effects with hydroxyurea, cytarabine, homoharringtonine, doxorubicin, and etoposide in all 4 cell lines. STI571 with 4-hydroperoxy-cyclophosphamide, methotrexate, or vincristine produced additive, antagonistic, and synergistic effects in 3 of 4 cell lines, respectively. These findings suggest that the simultaneous administration of STI571 with other agents except methotrexate would be advantageous for cytotoxic effects against Ph+ leukemias. Among them, the simultaneous administration of STI571 and α-interferons or vincristine would be highly effective against Ph+ leukemias and these combinations would be worthy of clinical trials. In contrast, the simultaneous administration of STI571 with methotrexate would have little therapeutic efficacy. Although there are gaps between in vitro studies and clinical trials, the present findings provide useful information for the establishment of clinical protocols involving STI571.
Competition between normal [674C] and mutant [674R]GPIIb subunits: role of the molecular chaperone BiP in the processing of GPIIb-IIIa complexes
Authors: Arias-Salgado Elena G. , Butta Nora , González-Manchón Consuelo , Larrucea Susana , Ayuso Matilde S. , Parrilla Roberto
Published: July 2002

This work aimed at investigating the function of the [C674R] mutation in GPIIb that disrupts the intramolecular 674 to 687 disulfide bridge. Individuals heterozygous for this mutation show a platelet GPIIb-IIIa content approximately 30% of normal controls, which is less than expected from one normal functioning allele. Coexpression of normal [674C]GPIIb and mutant [674R]GPIIb with normal GPIIIa produced a [674R]GPIIb concentration-dependent inhibition of surface exposure of GPIIb-IIIa complexes in Chinese hamster ovary (CHO) cells, suggesting that [674R]GPIIb interferes with the association and/or intracellular trafficking of normal subunits. Mutation of either 674C or 687C had similar effects in reducing the surface exposure of GPIIb-IIIa. However, substitution of 674C for A produced a much lesser inhibition than R, suggesting that a positive-charged residue at that position renders a less efficient subunit conformation. The mutant [674R]GPIIb but not normal GPIIb was found associated with the endoplasmic reticulum chaperone BiP in transiently transfected CHO cells. BiP was also found associated with [674R]GPIIb-IIIa heterodimers, but not with normal GPIIIa or normal heterodimers. Overexpression of BiP did not increase the surface exposure of [674R]GPIIb-IIIa complexes, indicating that its availability was not a limiting step. Platelets from the thrombasthenic patient expressing [674R]GPIIb-IIIa were found to bind soluble fibrinogen in response to physiologic agonists or dithiothreitol treatment. Thus, the [674R]GPIIb mutation leads to a retardation of the secretory pathway, most likely related to its binding to the molecular chaperone BiP, with the result of a defective number of functional GPIIb-IIIa receptors in the cell surface.