Viscosities and intradiffusion coefficients in the ternary system NaCl−MgCl2−H2O at 25°C

The intradiffusion coefficients of Na⁺, Cl^– ions and water and the tracerdiffusion coefficients of Ca²⁺ ion have been measured in the ternary system NaCl–MgCl₂–H₂O at 25°C. The intradiffusion coefficients of Mg²⁺ in this system have been estimated from the corresponding Ca²⁺ diffusion measurements. Viscosities were measured at the same solution concentrations as were used for the diffusion experiments. Intradiffusion and tracerdiffusion coefficients in a range of temperatures from 5 to 45°C are reported for standard sea-water which is a member of the above ternary set.     

The micro-determination of gold with p-dimethyl-aminobenzylidenerhodanine

Gold can be determined in the range 4–14 μg within 2% by a simple extraction of chlorauric acid in 0.12 N hydrochloric acid with a solution of p-dimethylaminobenzylidenerhodanine in iso-amyl acetate A 1:1 complex is formed with maximum absorption at 515 mμ.     

Evaluation of dried blood spot (DBS) technology versus plasma analysis for the determination of MK-1775 by HILIC-MS/MS in support of clinical studies

The collection of human blood samples as dried blood spots (DBS) for the pharmacokinetic assessment of investigational drugs in clinical trials offers a number of advantages over conventional plasma sampling, namely, small sample volume, simplified sample handling, and cost-effective shipping and storage. The use of DBS coupled with liquid chromatography–tandem mass spectrometry analysis was evaluated for the quantification of MK-1775, a Wee-1 inhibitor under development as a chemo/radio-sensitizer for the treatment of cancer. The DBS method exhibited an assay performance comparable to that of the existing plasma assay, which is currently used in support of clinical studies. Both assays used the same linear dynamic range of 2–1,000?ng/mL, with a lower limit of quantification of 2?ng/mL. Based on the intra-day assay validation results, the accuracy of the DBS method ranged from 94.0 to 105.0?%, with a coefficient of variation of <4.8?%. The blood-to-plasma ratio calculated from the DBS data (blood concentrations) and the plasma data (plasma concentrations) was in good agreement with the one obtained from the in vitro assessment using conventional methodology. No significant hematocrit impact on the assay was observed as hematocrit ranged from 16 to 85?%. The correlation between the measured MK-1775 concentrations in plasma and that determined in dried blood spots from oncology patients during the ongoing clinical study was discussed.     

The Kirwan Map for Singular Symplectic Quotients

Let M be a Hamiltonian K-space with proper moment map µ.The symplectic quotient X = µ^–1(0)/K is a singularstratified space with a symplectic structure on the strata.In this paper we generalise the Kirwan map, which maps the Kequivariant cohomology of µ^–1(0) to the middle perversityintersection cohomology of X, to this symplectic setting. The key technical results which allow us to do this are Meinrenken'sand Sjamaar's partial desingularisation of singular symplecticquotients and a decomposition theorem, proved in Section 2 ofthis paper, exhibiting the intersection cohomology of a ‘symplecticblowup’ of the singular quotient X along a maximal depthstratum as a direct sum of terms including the intersectioncohomology of X.     

Cohomology pairings on singular quotients in geometric invariant theory

In this paper we shall give formulas for the pairings of intersection cohomology classes of complementary dimensions in the intersection cohomology of geometric invariant-theoretic quotients for which semistability is not necessarily the same as stability (although we make some weaker assumptions on the action). We also give formulas for intersection pairings on resolutions of singularities (or more precisely partial resolutions, since orbifold singularities are allowed) of the quotients.     

Unusual magnetoresistance of mesophase-pitch-derived graphite fibers

Detailed measurements of the magnetoresistance of two types of high tensile modulus mesophase-pitch-derived graphite fibers have been performed between 1.4 and 300 K in magnetic fields to 8 T. With increasing magnetic field at low temperatures, the transverse magnetoresistance of these fibers exhibits an unusual oscillatory behavior.     

Coexistence of superconductivity and long-range antiferromagnetic order in Gd1.2Mo6Se8

Neutron diffraction experiments confirm that the ternary rare earth compound Gd_1.2Mo₆Se₈ orders antiferromagnetically in the superconducting state at a Neél temperature T_N=0.75 K.     

Bacteriorhodopsin α-helices in lipid settings: Insights for structure prediction

The two-stage model of membrane protein folding predicts that isolated transmembrane α-helices form stably in the bilayer before coming together to form the fully functional protein. Insight into the molecular implications of this model are possible with detailed molecular dynamics calculations. Thirty molecular dynamics simulations of both individual and pairs of α-helices from bacteriorhodopsin were calculated with the CHARMm program. This data base will continue to grow and expand. Already, differences between identical helices in different media and different helices in the same media have been found. The current results are summarized in this contribution. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 105–116, 1998