The system carbon dioxide-water is of great scientific and technological importance. Thus, it has been studied often. The literature for the solubility of carbon dioxide in water is vast and interdisciplinary. An exhaustive survey was conducted and approximately 100 experimental investigations were found that reported equilibrium data at pressures below 1 MPa. A model based on Henry’s law was used to correlate the low pressure data (those up to 1 MPa). The following correlation of the Henry’s constants (expressed on a mole fraction basis) was developed ln(H21/MPa)=−6.8346+1.2817×104/T−3.7668×106/T2 +2.997×108/T3 The correlation is valid for 273<T<433 K(0<t<160 °C) where T is in K. Any experimental data that deviated significantly from this model were duly noted.

For reactions of gas phase, ground state, neutral transition metal atoms from the 4d series with alkanes and alkenes, we combine 300 K kinetics measurements with ab initio electronic structure calculations to infer mechanisms in some detail. The theoretical method PCI-80 with zero-point energy corrections to the bare potential surface apparently produces bond energies, reaction exothermicities, and even saddle point energies accurate to within 2-3 kcal/mol, provided that the correct ground state has been located, which is sometimes difficult. The reactions fall into two general categories: termolecular stabilization of long-lived M(hydrocarbon) complexes and bimolecular elimination of Hz. By using the ab initio energies and vibrational frequencies in a statistical unimolecular rate theory (RRKM theory), we can model the lifetimes of M(hydrocarbon) complexes to assess the plausibility of a saturated termolecular mechanism at 1 Torr He. Termolecular examples include the reactions of Pd with alkanes to form long-range v2 complexes; the reactions of Rh and Pd with alkenes to form n complexes; and probably the reactions of Y, Zr, Nb, Rh, and Pd with cyclopropane to form CH or CC insertion complexes. In other reactions, all of the evidence indicates a bimolecular H2 elimination mechanism. Rhodium is unique among the 4d metal atoms in effecting HZ elimination from ethane and larger alkanes. Yttrium, zirconium, and niobium almost surely insert in CH bonds of ethylene and larger alkenes, ultimately eliminating H2. We discuss the general requirements on the pattern of atomic electronic states that pennit efficient CH bond activation and H2 elimination. The good agreement between the observed reaction rates and the PCI-80 calculations lends confidence to future efforts to apply ab initio techniques to more complicated catalytic systems, including condensed phase reactions involving ligated metal centers.

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Recently revealed problems with the fluid phase equilibria data for the system H, S-H,O as presented by Selleck et al. (1952) prompted this review of the hydrate-forming conditions. The smoothed tables of Selleck et al. (1952) along the three-phase loci are replaced with equations which are based on a critical review of all of the experimental data.Les problbmes soulevis ricemmenl h propos des donnees d'equilibre en phase liquide pour le systbme H,S-H,O telles qu'elles sont prisenties par Selleck et al. (1952) nous ont incites B examiner les conditions de formation des hydrates. Les tableaux lisses de Selleck et al. (1952) ainsi que les loci des trois phases sont remplaces par des Cquations basks sur un examen critique de toutes les donntes experimentales. ~

The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms from four HCC cell lines. Functional analysis following transfection and expression in HCC cells revealed distinct effects on the phenotype. The TCF-4J isoform expression produced striking features of malignant transformation characterized by high cell proliferation rate, migration and colony formation even though its transcriptional activity was low. In contrast, the TCF-4K isoform displayed low TCF transcriptional activity; cell proliferation rate and colony formation were reduced as well. Interestingly, TCF-4J and TCF-4K differed by only five amino acids (the SxxSS motif). Thus, these studies suggest that conserved splicing motifs may have a major influence on the transcriptional activity and functional properties of TCF-4 isoforms and alter the characteristics of the malignant phenotype.

The solubility of hydrogen sulfide and carbon dioxide in an aqueous solution containing 35 wt% methyldiethanolamine (MDEA) (3.04 kmol/m3, 4.52 mol/kg) has been measured at 40° and 100°C at partial pressures of the acid gas up to 530 kPa. Some data for hydrogen sulfide in a 50 wt% solution of MDEA (4.38 kmol/m3, 8.39 mol/kg) were also obtained. Also, densities of CO2‐aqueous MDEA solutions were measured at 40°C.

Upward and downward fluxes of shortwave radiation (0.285 < h < 2.8/•m) measured at Amundsen-Scott Station (South Pole) during the summers of 1975, 1976, and 1977 are analyzed to determine effective surface albedos as functions of cloudiness (N) and solar elevation angle (•l). For nonovercast conditions (N_< 0.25) the albedo decreases linearly from 0.97 at A •< 2 ø to a minimum of 0.83 + .005 for 20 ø. With near overcast conditions (N •> 0.7), linear decrease is also found from 0.93 at •l < 2 ø to 0.84 + 0.005 for •l > 18 ø. The nonovercast results are compared with albedos reported for other Antarctic plateau stations. The higher values at the South Pole are attributed to slower rates of surface snow metamorphosis there due to lower maximum sun elevations and absence of diurnal radiative flux and temperature cycles. Arguments are presented to resolve conflicting reports that cloudiness both increases and decreases the snow albedo, and our results show that the effect of clouds depends on the solar elevation angle.