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Abstract: Span and Wagner equation of state (SW EOS) have been used to investigate changes in the thermodynamic properties of CO2 during a depressurization process from a pipeline into marine environment. The process is assumed to be isenthalpic, as only the thermodynamic change at the moment of depressurization is considered. The calculations show that the depth location of the pipeline influences greatly the density, temperature and volume changes, because of the difference in the surrounding pressures. In general the two-phase area is reached at depths shallower than 600 meters, which yields for the Norwegian Continental Shelf, as it is mainly shallower than 500 meters depth. There is a rapid decrease in density in the two-phase area causing a rapid expansion in the volume of CO2 from 4MPa to 1MPa. At the shallowest depth considered (100m) the volume fraction consist almost entirely of gas, and the density change give a significant increase in volume. [Copyright &y& Elsevier]

Data from two Voluntary Observing Ship (VOS) (2005-2007) augmented with data subsets from ten cruises (1987-2005) were used to investigate the spatiotemporal variations of the CO2 fugacity in seawater (ƒCO2sw) in the North Sea at seasonal and inter-annual time scales. The observed seasonal ƒCO2sw variations were related to variations in sea surface temperature (SST), biology plus mixing, and air-sea CO2 exchange. Over the study period, the seasonal amplitude in ƒCO2sw induced by SST changes was 0.4-0.75 times those resulting from variations in biology plus mixing. Along a meridional transect, ƒCO2sw normally decreased northwards (-12 μatm per degree latitude), but the gradient disappeared/reversed during spring as a consequence of an enhanced seasonal amplitude of ƒCO2sw in southern parts of the North Sea. Along a zonal transect, a weak gradient (-0.8 μatm per degree longitude) was observed in the annual mean ƒCO2sw . Annually and averaged over the study area, surface waters of the North Sea were CO2 undersaturated and, thus, a sink of atmospheric CO2. However, during summer, surface waters in the region 55.5-54.5° N were CO2 supersaturated and, hence, a source for atmospheric CO2. Comparison of ƒCO2sw data acquired within two 1°×1° regions in the northern and southern North Sea during different years (1987, 2001, 2002, and 2005-2007) revealed large interannual variations, especially during spring and summer when year-to-year ƒCO2sw differences (≈160-200 μatm) approached seasonal changes (≈200-250 μatm). The springtime variations resulted from changes in magnitude and timing of the phytoplankton bloom, whereas changes in SST, wind speed and total alkalinity may have contributed to the summertime interannual ƒCO2sw differences. The lowest interannual variation (10-50 μatm) was observed during fall and early winter. Comparison with data reported in October 1967 suggests that the ƒCO2sw growth rate in the central North Sea was similar to that in the atmosphere. [ABSTRACT FROM AUTHOR]

Aims: Cancer stem-like cells might have important functions in chemoresistance. We have developed a model where highly infiltrative brain tumours with a stem-like phenotype were established by orthotopic transplantation of human glioblastomas to immunodeficient rats. Serial passaging gradually transformed the tumours into a less invasive and more angiogenic phenotype (high-generation tumours). The invasive phenotype (low-generation tumours) was characterized by an increase in stem cell markers and increased phosphorylation of kinases in the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. These markers were reduced in the serially passaged vascular tumours. The present study was aimed at investigating how the two phenotypes responded in vitro to doxorubicin, a clinically potent cytotoxic drug for solid tumours. Methods: Biopsy spheroids were implanted and passaged intracranially in nude rats. Gene expression and protein analyses were performed, and drug sensitivity was assessed. Results: Microarray analysis revealed gene ontology categories connected to developmental aspects and negative regulators of differentiation, especially in the infiltrative stem cell-like tumours. The highly invasive stem-like phenotype was chemoresistant compared with the angiogenic phenotype. By interfering with the PI3K it was possible to sensitize tumour spheroids to chemotherapy. Real-time quantitative polymerase chain reaction showed downregulation of the stem cell markers Nestin and Musashi-1 in low-generation biopsy spheroids following PI3K inhibition. Conclusions: Highly invasive tumours with a stem-like phenotype are more chemoresistant than angiogenic tumours derived from the same patients. We suggest that treatment resistance in glioblastomas can be related to PI3K/AKT activity in stem-like tumour cells, and that targeted interference with the PI3K/AKT pathway might differentiate and sensitize this subpopulation to chemotherapy. [ABSTRACT FROM AUTHOR]

Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO2) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO2. A self organizing map (SOM) neural network has been trained using 389 000 triplets of the SeaWiFSMODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137 000 underway pCO2 measurements collected in situ during 2004, 2005 and 2006 in the North Atlantic, spanning the range of 208 to 437 μatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 μatm, which equals to just above 3 per cent of an average pCO2 value in the in situ dataset. The seasonal pCO2 cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO2 fluxes or improvement of seasonal and interannual marine CO2 cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences. [ABSTRACT FROM AUTHOR]

The article presents the steps for quality control chosen parameters within the Arctic Ocean data which are included in the Carbon In the Atlantic (CARINA) data set. It notes the evaluated parameters which can be found in the CARINA data product including inorganic carbon parameters, oxygen, nitrate, phosphate and silicate. It infers the regional multi-linear regression, the method to identify the offsets between cruises after a first rough basin-wide deep-water estimate of each parameter.

The article offers information on the Carbon In the Atlantic (CARINA) data and its salinity measurements. It notes the need of CARINA data to undergo quality control (QC) to ensure highest possibly quality and consistency. It mentions that the evaluation of the consistency of the quality controlled salinity data suggests that they are consistent to at least 0.05.

We present the first year-long subpolar transatlantic set of surface seawater CO2 fugacity (fCO2sw data. The data were obtained aboard the MV Nuka Arctica in 2005 and provide a quasi-continuous picture of the fCO2sw variability between Denmark and Greenland. Complementary real-time high resolution data of surface chlorophyll a (chl a) concentrations and mixed layer depth (MLD) estimates have been collocated with the fCO2sw data. Off the shelves the fCO2sw goes through a pronounced seasonal cycle. Surface waters are saturated to slightly supersaturated over a wide range of temperatures in winter. Through spring and summer fCO2sw decreases by approximately 60 &micro due to biological carbon consumption which is not fully counteracted by the fCO2sw increase due to summer warming. The changes are synchronous with changes in chl a concentrations and MLD, and fCO2sw 2 is correlated to both of these through exponential decay and growth curves, respectively. In particular, MLD appears to be able to predict open ocean subpolar fCO2sw to within 12 µatm using a single equation for the whole year. The predictive capability of chl a is around 20% less, with root mean 15 square values of 14.5 µatm. As fCO2sw extrapolation parameters, both MLD and chl a outperform sea surface temperatures in the open subpolar North Atlantic. However, the situation on the shelves is much more heterogeneous and the fCO2sw -parameter relationships are not as strong as they are off the shelves. [ABSTRACT FROM AUTHOR]

Abstract: Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward the catalytic surface through the annulus between the tubes, and the gas is sampled close to the surface by the capillary. The influence of various design parameters on the lateral resolution and sensitivity of the measurements is investigated. It is found that the outer diameter of the annulus sets the upper limit for the lateral resolution of the measurement, and that a flow rate of the order of 240(ml/min) n is sufficient to achieve this resolution. The sensitivity is reasonable also with high flow rates, due to the presence of a pocket of stagnant gas under the tip of the capillary. Furthermore, the limits of the range in reaction rate, which can be studied are estimated. [Copyright &y& Elsevier]

The paper presents an improved approach for the measurement of Cu-dispersion in catalysts using the oxidation of the Cu surface atoms by N2O. During a single easy-to-perform experiment, the degree of surface and bulk oxidation of copper can be separated due to a continuous measurement of evolved N2, which leads to a more accurate measurement of the copper surface.The measurement is made at ambient pressure with a constant flow of gas through a fixed bed of catalyst particles by switching the feed gas composition from pure helium to 2% N2O in helium. The effluent gas passes through a freeze trap with liquid nitrogen, which selectively removes any unreacted N2O from the gas. Nitrogen evolved by the oxidation reaction is not removed in the N2O trap and a binary mixture of nitrogen diluted in helium carrier gas is then measured accurately directly in a calibrated thermal conductivity detector (TCD).Five methanol synthesis catalysts (Cu/ZnO/Al2O3), which differ in terms of the copper surface area are studied by this method. All recorded TCD-signals consist of two features: first, a significant peak appearing immediately after the switch from He to N2O in He, which is attributed to a fast surface reaction. Secondly, the peak is followed by a long tail, which is due to slow formation of N2 due to a diffusion-limited oxidation of bulk copper atoms. During the tailing part of the experiment, the N2O-reactions is under differential condition and the produced N2 is continuously removed by the He carrier gas.By the new experimental procedure we can separate the two parts of the N2-signal, i.e. a rapid surface oxidation and a slow solid state diffusion-limited bulk oxidation. As a result, we can - based on a mathematical correction for the influence of diffusion—make a more accurate measurement of the copper surface area. Measurements made at different temperatures show—as expected—an increase in bulk oxidation rate due to the temperature dependence of oxygen diffusion in the upper oxide layer. For precision it is recommended, though, to measure under conditions where the influence of bulk diffusion is small, that is below 90 °C.The method is fast, simple, sensitive and versatile and only requires a thermal conductivity cell for the analysis. [Copyright &y& Elsevier]

The flame combustion synthesis of Cu/ZnO/Al2O3 catalysts for the synthesis of methanol from CO, CO2, and H2 is investigated. The oxides are generated in a premixed flame from the acetylacetonate vapours of Cu, Zn, and Al mixed with the fuel and air prior to combustion. The flame-generated powder is examined by X-ray powder diffraction, determination of the specific surface area by the BET method, determination of the copper dispersion in the reduced catalyst by a novel N2O method, transmission electron microscopy, and testing of the catalytic properties in a catalytic microreactor. A low peak temperature and quench cooling of the flame tend to increase the dispersion of the phases and the specific surface area of the particles. Properties of both the ternary composition, the three binary compositions, and the pure oxides are discussed. The calculation of simultaneous phase and chemical equilibrium is used in the assessment of the phase composition of the particles. The specific surface area varies from 100 m2/g or a little below for samples without Al to several hundred m2/g for the respective compositions of pure Al2O3 and ZnAl2O4. Copper dispersion after reduction varies from 1.8 to 14.1%. A ternary catalyst with the composition of Cu:Zn:Al = 45:45:10 has the highest catalytic activity of all samples tested. This catalyst is also very selective and stable toward thermal deactivation. The role of the individual catalyst components in the optimal catalyst is discussed. [Copyright &y& Elsevier]

For 20 years the Convention on Long-range Transboundary Air Pollution has worked to control air pollutant emissions in Europe and North America. Its Working Group on Effects (WGE) has been responsible for much of the underpinning science. The WGE's six International Cooperative Programmes (ICPs) on Waters, Natural Vegetation and Crops, Forests, Materials and Cultural Heritage, Integrated Monitoring, and Modelling and Mapping, together with a Joint Task Force on Human Health with WHO, quantify air pollution effects on the environment through monitoring, modelling and scientific review. Early work found evidence to support the need for decreases in emissions of sulphur and nitrogen pollutants. More recently, monitoring results and models have provided the scientific basis, e.g. critical loads and levels, for effects-based Protocols and for evaluating their effectiveness. ICP studies on trends show recovery from acidification effects in keeping with the fall in sulphur emissions. Steady-state models provide an indication of long-term improvements. Recent increased emphasis on developing dynamic models will enable better links between recovery rates and abatement strategies. The scientific network of the ICPs and the monitoring and modelling results have been key to the development of the Convention and are an essential component for its success in the future. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) and alumina (Al2O3) particles are synthesized by the combustion of their volatilized acetylacetonate precursors in a premixed air–methane flame reactor. The particles are characterized by XRD, transmission electron microscopy, scanning mobility particle sizing and by measurement of the BET specific surface area. Pure (γ-)alumina particles appear as dendritic aggregates with average mobile diameter 43–93 nm consisting of partly sintered, crystalline primary particles with diameter 7.1–8.8 nm and specific surface area 184–229 m2/g. Pure zinc oxide yields compact, crystalline particles with diameter 25–40 nm and specific surface area 27–43 m2/g. The crystallite size for both oxides, estimated from the XRD line broadening, is comparable to or slightly smaller than the primary particle diameter. The specific surface area increases and the primary particle size decreases with a decreasing flame temperature and a decreasing precursor vapour pressure. The combustion of precursor mixtures leads to composite particles consisting of zinc aluminate ZnAl2O4 intermixed with either ZnO or Al2O3 phases. The zinc aluminate particles are dendritic aggregates, resembling the alumina particles, and are evidently synthesized to the full extent allowed by the overall precursor composition. The addition of even small amounts of alumina to ZnO increases the specific surface area of the composites significantly, for example, zinc aluminate particles increases to approximately 150 m2/g. The gas-to-particle conversion is initiated by the fast nucleation of Al2O3 or ZnAl2O3, succeeded by a more gradual condensation of the excess ZnO with a rate probably controlled by the cooling rate for the flame. [ABSTRACT FROM AUTHOR]

This multicentre, double-blind, randomized parallel-group study compared 3 weeks' treatment with either loratadine (Clarityn®) 10 mg once daily, or clemastine (Tavegyl®) 1 mg twice daily, and placebo in outpatients with active perennial allergic rhinitis. 155 patients were evaluated for efficacy and safety. Grading of four nasal and three non-nasal symptoms, rhinoscopy signs, and therapeutic response was performed on treatment days 6, 13, and 20. Patients recorded daily symptoms and possible adverse experiences in a diary, also indicating when symptoms of active rhinitis were relieved. Loratadine and clemastine were statistically significantly superior to placebo throughout the study (P< 0.05), based on assessment of patients' nasal and eye symptoms, patients' diary scores, rhinoscopy signs of symptoms, and onset of relief. The loratadine group showed a statistically significantly (P< 0.05) faster onset of relief of symptoms compared with the group treated with clemastine. Concerning nasal stuffiness, loratadine was significantly (P< 0.05) superior to clemastine after 1 week's treatment. Reports of adverse reactions showed that significantly (P< 0.05) more patients complained of sedation in the clemastine than in the loratadine group. Regarding other adverse experiences and laboratory tests, the three treatment groups were statistically comparable (P< 0.05). The study showed that compared with placebo both loratadine and clemastine were effective in relieving nasal and eye symptoms in patients with perennial allergic rhinitis. Loratadine was safe and well tolerated and was significantly less sedative than clemastine; loratadine may therefore possess an advantage in clinical use in the treatment of perennial allergic rhinitis. [ABSTRACT FROM AUTHOR]