bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of the tonsil cytokine milieu favors HIV susceptibility
Authors: Moutsopoulos Niki M , Vázquez Nancy , Greenwell-Wild Teresa , Ecevit Ismail , Horn Judith , Orenstein Jan , Wahl Sharon M 
Published: August 2006

Abstract
Mucosal associated lymphoid tissues are major targets of HIV during early infection and disease progression but can also provide a viral safe haven during highly active antiretroviral therapy. Among these tissues, the tonsils remain enigmatic regarding their status as primary and/or secondary sites of retroviral infection. To dissect the mechanisms underlying susceptibility to HIV in this compartment, isolated tonsil cells were studied for phenotypic and functional characteristics, which may account for their permissiveness to infection. For this, tonsil cells and PBMC were infected in parallel with HIV, and viral replication was monitored by p24 ELISA. Our results demonstrate that unstimulated tonsil cells were more readily infected than PBMC with HIV. Phenotypic characterization of the tonsil cells revealed heterogeneous lymphoid populations but with increased expression of early activation markers and the viral co-receptor CXCR4, relative to PBMC, all of which may contribute to viral susceptibility. Furthermore, the cytokine microenvironment appeared to be key in facilitating HIV infection and tonsil-secreted products enhanced HIV infection in PBMC. Of the cytokines detected in the tonsil supernatants, TH2 cytokines, particularly IL-4, promoted HIV infection and replication. Interestingly, this TH2 profile appeared to dominate, even in the presence of the TH1 cytokine IFNγ and the anti-viral factor IFNα, likely due to the enhanced expression of suppressor of cytokine signaling (SOCS) proteins, which may disengage IFN signaling. These and other local environmental factors may render tonsil cells increasingly susceptible to HIV infection.
Mycobacterium avium-induced SOCS contributes to resistance to IFN-γ mediated mycobactericidal activity in human macrophages
Authors: Vázquez Nancy , Greenwell-Wild Teresa , Rekka Sofia , Orenstein Jan M , Wahl Sharon M 
Published: August 2006

AbstractMycobacterium avium is an opportunistic pathogen that commonly infects individuals colonized with HIV-1, although it is less frequent in the post-HAART era. These microorganisms invade macrophages after interacting with TLR2 and/or CD14 co-receptors, but signaling pathways promoting survival in macrophages are not well defined. Although IFN-γ plays an important role in protective immunity against bacterial infections, IFN-γ responses are compromised in AIDS patients and evidence suggests that exogenous IFN-γ is inadequate to clear the mycobacteria. To determine the mechanism by which M. avium survives intracellularly, even in the presence of IFN-γ, we studied the effect of mycobacteria infection in macrophages during early IFN-γ signaling events. M. avium infected cells exhibited a reduced response to IFN-γ, with suppressed phosphorylation of STAT-1 compared with uninfected cells. Interaction of M. avium with macrophage receptors increased gene expression of the suppressors of cytokine signaling (SOCS) to diminish IFN responsiveness. Specifically, we observed an increase in mRNA for both SOCS-3 and SOCS-1, which correlates with elevated levels of SOCS protein and positive immunostaining in M. avium/HIV-1 co-infected tissues. We also linked the p38 MAPK signaling pathway to mycobacterial-induced SOCS gene transcription. The induction of SOCS may be part of the strategy that allows the invader to render the macrophages unresponsive to IFN-γ, which otherwise promotes clearance of the infection. Our data provide new insights into the manipulation of the host response by this opportunistic pathogen and the potential for modulating SOCS to influence the outcome of M. avium infection in immunocompromised hosts.
Escitalopram and paroxetine in the treatment of generalised
anxiety disorder
Authors: Baldwin David S. , Huusom Anna Karina Trap , Mæhlum Eli 
Published: August 2006

BackgroundIt is uncertain whether higher doses of selective serotonin reuptake
inhibitors have greater efficacy in generalised anxiety disorder.AimsTo assess the efficacy of different doses of escitalopram in generalised
anxiety disorder.MethodRandomised, double-blind, placebo-controlled, fixed-dose, parallel-group,
12-week study, with 681 patients: placebo (n=139);
escitalopram, 5 mg/day, (n=134); 10 mg/day
(n=136); 20 mg/day (n=133);
paroxetine, 20 mg/day (n=139).ResultsMean change in the primary efficacy measure was greater with escitalopram
10 and 20 mg than with placebo; 10 mg was more efficacious than
paroxetine. Paroxetine was superior to placebo on some secondary
measures, at sometime points. Compared with placebo, more patients
withdrew because of adverse events with escitalopram 20 mg and
paroxetine.ConclusionsEscitalopram was efficacious in generalised anxiety disorder, 20 was not
significantly superior to 10 mg/day Escitalopram 10 mg was more
efficacious than paroxetine.
Attention to the eyes and fear-recognition deficits in child
psychopathy
Authors: Dadds Mark R. , Perry Yael , Hawes David J. , Merz Sabine , Riddell Alison C. , Haines Damien J. , Solak Emel , Abeygunawardane Amali I. 
Published: August 2006

SummaryThe ability to recognise fear is impaired in people with damage to the
amygdala and, interestingly, in adult psychopathy. Here we confirm that
deficits in recognising fear exist in children with psychopathic traits. We
show for the first time that, as with patients with amygdala damage, this
deficit can be temporarily corrected by simply asking them to focus on the
eyes of other people. These data support models of psychopathy that
emphasise specific dysfunction of the amygdala and suggest an innovative
approach for intervening early in the development of psychopathy.
Psychiatry at night: experience of the senior house officer
Authors: Mason Jules , Irani Tina , Fountoulaki Garyfallia , Warwick Sylvia , da Roza Davis Jane , Sudbury Peter 
Published: August 2006

Aims and MethodWe gathered detailed prospective data for first on-call activity of senior house officers (SHOs) in order to help plan changes in service provision so that SHOs in psychiatry complied with the Working Time Directive and to determine whether service changes affected training experience while on call. The incumbent SHOs designed a simple form to monitor on-call activity in West Berkshire.ResultsAdmissions and assessments make up a quarter of calls but three-quarters of the work. An overnight crisis service reduced the number of assessments made by SHOs out of hours by 68%. Screening of calls by a senior nurse reduced the number of calls about in-patients by 60% on weekday nights. Between 73% and 100% of calls about in-patients after midnight were for assessment of patients in seclusion and rapid tranquillisation.Clinical ImplicationsThis survey helped to plan service delivery and to monitor the training of SHOs during on call. Screening of calls by a senior nurse, alternatives to seclusion and nurse-led prescribing for rapid tranquillisation would have the largest impact on the work generated by in-patients. The overnight crisis service reduced the number of assessments, but might have an adverse impact on training.
Electron-Optical Study of Smectites
Authors: Mering J. , Oberlin A. 
Published: August 2006

AbstractThe combined use of electron microscopy and of selected area diffraction (SAD) has been applied to the study of montmorillonites from Wyoming and from Camp-Berteaux, of nontronite, and of hectorite. The study shows that only the elementary layers of the Wyoming montmorillonite and of the nontronite are single two-dimensional crystals. The elementary layers of the montmorillonite from Camp-Berteaux are formed by edge-to-edge associations of very small elements with mutual orientations of about 60° or multiples of 60°. The layers of hectorite are formed by edge-to-edge association of laths with fluctuations of orientation of the order of 10° rotation around adjoining edges. The SAD patterns of Wyoming montmorillonite show that the single layer plane symmetry group of this mineral is c1m1; nontronite layers belong to the symmetry group c2mm. The study of thick particles shows that in turbostratic smectites the layers are stacked with mutual rotations around the perpendicular to their plane. This mode of stacking explains the absence of hkl reflections. High resolution diffraction (HRD) patterns obtained with sample inclined to the electron beam show that only the structure of hectorite approaches the ideal model; nontronite and montmorillonite exhibit appreciable distortions with respect to the ideal model. HRD diagrams provide precise information for the refinement of the crystal structures of smectites
Electron Diffraction and Micrographic Study of the High-Temperature Changes in Illite and Montmorillonite Under Continuous Heating Conditions
Authors: Furlong Robert B. 
Published: August 2006

AbstractTransmission and diffraction electron micrographs were made of illite and montmorillonite to study the changes that take place as the clays were heated continuously to 1200°C.In both of the clay minerals studied, expulsion of a highly fluid material occurred subsequent to dehydroxylation and prior to the development of the first-formed high temperature phases. It was hypothesized that this material represented the expulsion of constituents in the clay in excess of those needed for the formation of the first high-temperature phase. Electron diffraction indicates that the high-temperature phases that formed all developed with some preferential orientation, and were strongly influenced in their development by the structure of the original clay.
Sorption of Water at High Temperatures on Certain Clay Mineral Surfaces. Correlation with Lattice Fluoride
Authors: Granquist W. T. , Kennedy J. V. 
Published: August 2006

AbstractThe sorption of water, at 490°C and ca. 23–24 torr, on clay mineral surfaces has been studied using thermogravimetry and infrared absorption spectroscopy. Results from a series of synthetic hectorites, with and without lattice fluoride (see Granquist and Pollack, 1960), point to the presence of F− in the clay lattice as an important condition for the sorption. Similar studies on natural hectorite and montmorillonite, synthetic interstratified montmorillonite/mica with and without fluoride, and Al2F6 support this interpretation of the role of the F− ion and show that dioctahedral 2:1 clays sorb more water at 490°C than do trioctahedral 2:1 clays. The infrared spectra demonstrate that the sorbed water is for the most part hydrogen-bonded to the surface.
Infrared Absorption Spectrometry in Clay Studies
Authors: Farmer V. C. , Russell J. D. 
Published: August 2006

AbstractThe relationships between spectrum and structure in layer-silicates are reviewed, and applied in the study of structural changes occurring during the heating of montmorillonites up to dehydroxylation, and their subsequent rehydroxylation. Information given by infrared spectroscopy on the binding of water in expanding layer silicates is presented, and the physical and chemical processes associated with entry of basic, neutral and acidic molecules into the interlayer space of these minerals are illustrated for ammonia, ethylamine, pyridine, nitrobenzene, and benzoic acid. Problems associated with the study of soil clays, which are often complex mixtures including poorly ordered and amorphous constituents, frequently firmly combined with organic matter, are discussed.New evidence is presented concerning the environment of the two types of hydroxyl group in beidellite. The thermal stabilities of NH4+ and lattice OH in montmorillonite and beidellite, and the properties of their dehydroxylates, are contrasted. The nature of the collapsed phase formed in Li-, Mg-, and NH4-montmorillonite at 300–500°C is discussed. The presence of weak hydrogen bonds between lattice oxygens and interlayer water is established, although it is shown that the strength of hydrogen bonds formed between NH4+ and lattice oxygens is dependent on the sites of substitution in the layer lattice.
Influence of Exchange Ions on the b-Dimensions of Dioctahedral Vermiculite
Authors: Leonard R. A. , Weed S. B. 
Published: August 2006

AbstractThe 1–5 μ size fractions of different ground muscovites were treated for a 30-day period for K+ removal with a pH 7.5 solution containing sodium tetraphenylboron. The initial K+ contents ranged from 211 to 219 me/100 g. After the extraction period, the final K contents ranged from 21 to 37 me/100 g. The apparent structural charge on the expanded material decreased to values ranging from 156 to 184 me/100 g, which are within the charge range for natural vermiculites. The b-dimensions of these laboratory-produced vermiculites were found to vary with the exchange ion and with the hydration state of the ion. For hydrated samples, saturation with Cs+, Li+, and Mg2+ ions increased the observed b-dimension in comparison to that of the corresponding parent mica, whereas saturation with Sr2+ and La3+ ions had little effect on b. After dehydration at 350°C, only Cs+-saturated samples had a b-dimension greater than that of the parent mica. The observed b-dimension for the dehydrated samples was found to be a direct function of the crystal radius of the interlayer ion. Apparently, as the ion dehydrates, the surface oxygen triads rotate until some of the oxygens “lock” onto the ion, limiting the minimum b-dimension. Before dehydration, however, the water of hydration in the interlayer region is evidently held with sufficient energy to limit rotations of the oxygen triads that give rise to a decrease in b. When Li+ and Mg2+ ions occupy the interlayer region, their water network apparently even produces a slight increase in the observed b-dimension.
Clay Minerals and Oceanic Evolution
Authors: Harriss Robert C. 
Published: August 2006

AbstractA review of mineralogical and geochemical studies on Recent sediments indicates that the clay fraction of marine sediments is not in isotopic or chemical equilibrium with the oceanic reservoir and will not reflect the chemical environment of deposition. Consideration of the sedimentary geochemistry of the alkali metals suggests that fractionation of these elements, which may be one of the major features of the chemical evolution of ocean water, occurs in the terrestrial weathering environment during the formation of clay minerals and in the subsurface environment during clay mineral diagenesis. It is proposed that during the initial stages of oceanic development the Na/K ratio of ocean water was adjusted to a value of forty to fifty by the extensive diagenesis of the existing natural water. With an increase in oceanic volume and a major change in the hydrologic cycling of natural waters the chemical evolution of alkali metals in ocean water has now become primarily controlled by mixing with continental drainage water.
Pressure Effects on Conductance of Frozen Montmorillonite Suspensions
Authors: Hoekstra P. , Keune R. 
Published: August 2006

AbstractThe influence of pressure on the conductance of frozen montmorillonite suspensions was measured in the temperature range from 0°C to − 12°C on Na- and Ca-saturated samples. Pressures invariably increase the conductance of frozen suspensions. The change in conductance with pressure is postulated to be due to pressure melting of the ice in the frozen suspension. From swelling pressure data the increase in unfrozen water with pressure at constant temperature is calculated and shown to be consistent with the effect of pressure on conductance.
Interlamellar Reactions of Tetracalcium Aluminate Hydrates with Water and Organic Compounds
Authors: Dosch Werner 
Published: August 2006

AbstractTetracalcium aluminate hydrates are the first example of layer-structured crystals containing neutral sheets, which are highly capable of interlamellar adsorption of water and neutral organic compounds. In this respect tetracalcium aluminate hydrates present new aspects of the phenomenon of swelling, and bring about the challenge of comparison with the frequently examined clay-organic compounds.This report is concerned with the probable monolayer structure of tetracalcium aluminate hydrate which forms five hydration stages. A summary concerning configuration and properties of adsorption complexes with approximately 500 selected organic substances follows. As far as these substances are homologues of certain functional groups, the change of basal distances depends upon the number of C-atoms.Aside from pure organic compounds, one can also form interlamellar complexes with a mixture of such compounds. Here again a rule of proportion between the number of C-atoms and the basal distance becomes evident. Another variant is the mixed interlamellar complexing of water with organic compounds and the re- and de-hydration reactions of these products.The report discusses the bonding conditions of various functional organic groups to the inorganic lattice. Furthermore, a series of homopolar organic derivatives of the tetracalcium aluminate hydrates can be produced. As is known, the existence of such compounds of clay minerals is a subject of dispute.
The Influence of Alkaline Solutions on the Alteration of the Clay Minerals
Authors: Ferrell Ray E. , Grim Ralph E. 
Published: August 2006

AbstractThe influence of an alkaline environment on clay mineral alterations in the laboratory was studied by means of one-dimensional structural analyses. Samples of illite, illite-mixed-layered material, kaolinite, and two montmorillonites (smectites) were treated with NH4OH solutions of pH 8.5, 9.5, 10.5, 11.5, and 12.5 for 6, 12, 24, 48, 72, and 96 hr at 60°C.One-dimensional structural analyses of the treated samples are quite demonstrative in determining the effects of laboratory-controlled degradation. These analyses show an oscillatory change in the population of the tetrahedral and octahedral structural sites which is consistent with a core-rind structural concept of the clay minerals. Leaching of clay minerals takes place by the alternate growth of the rind and destruction of this frayed edge by agitation. The extent to which the rind develops is controlled by particle size, variability of chemical composition, and the amount of agitation. The order of increasing development of the frayed edge is; kaolinite, illite, illite-mixed-layered material, and then the montmorillonite.
Surface Properties and Texture of Chrysotiles
Authors: Fripiat J. J. , della Faille M. 
Published: August 2006

AbstractNitrogen surface areas and pore-size distribution curves of various chrysotiles have been measured using a continuous flow method. A model founded on a hexagonal close packing of fibers has been adjusted to fit the frequency distribution curve of the fiber outside diameters obtained from electron micrographs. From this model, theoretical distribution functions of the surface area versus the pore diameter were computed and compared to the experimental data. For one fiber only (i.e. Coalinga chrysotile), the good agreement between the computed and experimental data allows one to conclude that the external pores (between the fibers) and the internal pores (within the fibers) are free from any amorphous material. For the other studied chrysotiles, the degree of filling of the pore system by amorphous materials was always higher than 50%. Under these conditions, hydration water cannot be removed unless the samples are pretreated in the 300°–400°C temperature range. On the contrary, water is driven off from the “clean” Coalinga fibers at temperatures lower than 100°C. Surface area measurements derived from water-adsorption isotherms correspond to those obtained with nitrogen after the hydration water has been removed.
Visible Changes in Macro Mica Particles That Occur with Potassium Depletion
Authors: Scott A. D. , Smith S. J. 
Published: August 2006

AbstractMica particles approximately 10 or 25 mm square and 0.5 mm thick were placed in NaCl-NaTPB solutions to make visual observations of the changes that occur in micas when the interlayer K is replaced by Na. Samples of muscovite, biotite, phlogopite, lepidolite, and lepidomelane were used, and the effects of different degradation periods were photographed.An increase in the thickness of the particles due to basal planes splitting apart was observed with all micas. This exfoliation released interlayer K and in some cases caused the particles to cleave into separate flakes. Lepidomelane particles remained intact despite a 20-fold increase in thickness in 7 days. Even muscovite and lepidolite exfoliated and cleaved, but much longer degradation periods were needed.There was a distinct change in the color of the dark biotite, phlogopite and lepidomelane particles when K was removed. Therefore, the initial stages of K depletion at holes, scratches, and edges of the particles were easily followed. As the degradation of the mica particles progressed, however, the color of the mica became a less reliable index of the stage of K depletion. Visual evidence of K depletion at the edges of particles was also obtained with muscovite, but not with lepidolite.Transverse sections of 25-mm particles of K-depleted biotite were photographed to show the edge expansion that occurred when interlayer K was replaced by Na.
Biotites Intermediate Between Dioctahedral and Trioctahedral Micas
Authors: Rimsaite J. 
Published: August 2006

AbstractOrange-yellow detrital flakes of biotite are common carriers of potassium and trace elements in soils and clays. Because the flakes differ in degree of alteration and may be derived from different sources, it is difficult to obtain homogeneous material for studies of their physical and chemical properties that may be compared with the original mica. A similar orange-yellow altered biotite occurs with fresh biotites in alkalie rocks of a nepheline deposit. The fresh and altered biotites were separated for chemical and minoralogical studies of the effects of weathering on biotite in its parent rock.The common iron-rich biotites with octahedral occupancy between 5.5 and 5.8 alter to bright orange-yellow biotites with octahedral occupancy approaching five. These biotites, intermediate between the trioctahedral and dioctahedral micas, form as a result of oxidation during the process of their alteration to chlorite—vermiculite.Biotites with octahedral occupancy approaching five were prepared experimentally by heating a natural biotite that contained high ferrous iron. The main differences between the natural and laboratory oxidized biotites are: the naturally oxidized micas lose 30% of the original potassium, adsorb about 2 wt.% water, and apparently gain about 25% hydroxyl, whereas laboratory oxidized micas retain potassium and lose hydroxyl and argon. The oxidized micas retain the crystal structure of the original mica.
Clay Mineralogy of Andesite Saprolite
Authors: Hendricks D. M. , Whittig L. D. , Jackson M. L. 
Published: August 2006

AbstractClay mineral associations in saprolite of two andesites from the Cascade Range of northeastern California were determined. Sesquioxidic allophane with a high CEC delta value dominates the clay fraction of the least weathered saprolite in each series (47% and 37% in hypersthene andesite and olivine andesite saprolites, respectively). With further weathering, the content of amorphous clay remains high (over 30% in all cases) but the CEC delta value of the clay drops markedly. The amorphous material in the more weathered saprolite has the properties of halloysitic allophane. Halloysite, present in all saprolites, is highest in concentration (over 30%) in the more strongly weathered members of each of the saprolite series. Formation of sesquioxidic allophane during early stages of weathering and its transformation to halloysitic allophane and halloysite during later stages of weathering are supported by X-ray diffraction, electron microscopic, DTA, elemental analysis, and CEC delta value data.