The International Stripa Project: an overview

The International Stripa Project was a cooperative research and development project among several member countries of the Nuclear Energy Agency of the Organization for Economic Cooperation and Development. The scientific and technical objectives of the project were to investigate several aspects of technology concerned with the feasibility and safety of disposal of long-lived, heat-generating radioactive waste at depth in granitic rocks. In particular, the Stripa Project addressed: 1) the development of instruments and procedures to characterize candidate repository sites; 2) the understanding and modelling of groundwater flow and solute transport in fractured crystalline rock; and 3) the design of engineered barriers capable of contributing to waste isolation by restricting groundwater flow in proximity to the waste containers and in the surrounding host rock. This overview summarizes the work focussed on natural barriers and engineered barriers.     

Predicting episodic memory performance in dementia: Is severity all there is?

Whether individual differences in demographic, psychometric, and biological domains can predict episodic memory in dementia was investigated. Mildly to moderately demented very old persons performed episodic memory tasks (free recall and recognition of slowly and rapidly presented random words, free and cued recall of organizable words, and recognition of dated and contemporary famous faces). A factor analysis of the memory measures yielded 2 factors, 1 indexing recall and 1 recognition. Controlling for severity of dementia, only 2 predictors contributed to performance: (a) Block Design (a marker of fluid intelligence) was positively related to recall, and (b) age was negatively related to recognition. Although these results are similar to data reported on predictors of episodic memory in normal aging, (a) the number of predictive variables appears to be reduced in dementia, and (b) age seems to affect recall and recognition differentially in normal aging and dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mass fragmentographic determination of docosenoic acid in rapeseed oils

A highly sensitive and accurate reference method for determination of docosenoic acid (mainly erucic acid, 22∶1n−9) in different rapeseed oils is described. A fixed amount of [1-¹⁴C]erucic acid methyl ester (about 1 μg) is added to a fixed amount of oil. After treatment with sodium methoxide/methanol reagent and extraction with hexane, the amount of unlabeled erucic acid is determined from the ratio between the recordings at m/e 320 and m/e 322 obtained after analysis with a combined gas chromatograph-mass spectrometer equipped with an MID (multiple ion detector). The two ions used correspond to the M-32 peak in the mass spectrum of unlabeled and [1-¹⁴C]labeled erucic acid methyl ester. The relative standard deviation of the method is about 1.8%. The method was compared with a gas chromatographic method for determination of erucic acid.     

Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments

The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.     

The parallel implementation of the one-dimensional Fourier transformed Vlasov-Poisson system

A parallel implementation of an algorithm for solving the one-dimensional, Fourier transformed Vlasov-Poisson system of equations is documented, together with the code structure, file formats and settings to run the code. The properties of the Fourier transformed Vlasov-Poisson system is discussed in connection with the numerical solution of the system. The Fourier method in velocity space is used to treat numerical problems arising due the filamentation of the solution in velocity space. Outflow boundary conditions in the Fourier transformed velocity space removes the highest oscillations in velocity space. A fourth-order compact Padé scheme is used to calculate derivatives in the Fourier transformed velocity space, and spatial derivatives are calculated with a pseudo-spectral method. The parallel algorithms used are described in more detail, in particular the parallel solver of the tri-diagonal systems occurring in the Padé scheme.

Program summary

Title of program:vlasovCatalogue identifier:ADVQProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVQProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandOperating system under which the program has been tested: Sun Solaris; HP-UX; Read Hat LinuxProgramming language used: FORTRAN 90 with Message Passing Interface (MPI)Computers: Sun Ultra Sparc; HP 9000/785; HP IPF (Itanium Processor Family) ia64 Cluster; PCs clusterNumber of lines in distributed program, including test data, etc.:3737Number of bytes in distributed program, including test data, etc.:18 772Distribution format: tar.gzNature of physical problem: Kinetic simulations of collisionless electron-ion plasmas.Method of solution: A Fourier method in velocity space, a pseudo-spectral method in space and a fourth-order Runge-Kutta scheme in time.Memory required to execute with typical data: Uses typically of the order 10⁵-10⁶ double precision numbers.Restriction on the complexity of the problem: The program uses periodic boundary conditions in space.Typical running time: Depends strongly on the problem size, typically few hours if only electron dynamics is considered and longer if both ion and electron dynamics is important.Unusual features of the program: No     

Regio- and enantioselectivities in epoxide conjugations are modulated by residue 210 in Mu class glutathione transferases

The homologous human glutathione transferases (GSTs) M1-1 and M2-2 have similar catalytic activities with many electrophilic substrates, but differ strikingly in their conjugation of epoxides with glutathione. Residue 210, Thr in GST M2-2 and Ser in GST M1-1, is a key active-site component in determining the activity profile with epoxide substrates. This residue is hypervariable in Mu class GSTs, suggesting that it has special significance in the evolution of new functions. The present study shows that minor modifications of this residue can have major consequences for the enzyme-catalyzed epoxide conjugations. In general, a Ser at position 210 gives the highest catalytic efficiency, but the relatively high activity with an Ala placed on this position demonstrates that a hydroxyl group is not required. In contrast, a Thr residue suppresses the activity with epoxides by several orders of magnitude without major effects on the activity with alternative GST substrates. Residue 210 influences both the regio- and enantioselectivity with chiral and prochiral epoxides of stilbene and styrene and influences the distribution of isomeric glutathione conjugates. Thus, residue 210 contributes to both stereoselective recognition of the substrates and to partitioning of the isomeric reactants to the alternative transition states leading to separate chiral products.     

A solar cell with enhanced photocurrent

Calculations have been performed on an n⁺p-solar cell structure with an added smaller bandgap extra layer. Continuity in the valence band is assumed between the two different semiconductor materials. In this way the usual requirement in a tandem cell of equal photo carrier generation in the different materials is relaxed.     

Activities in dilute solutions of chromium and iron in nickel at 1600° by mass spectrometry

Binary and ternary alloys of chromium and iron with nickel were studied. The total solute content ranged from 1 to 10 at. pct. The first-order interaction coefficients for chromium are ε_Cr ^(Cr)= 1.8 ±2.0, and ε_Cr ^(Fe) = 0.6 ± 5.0 (twice standard deviation). The relative partial molar enthalpy of liquid chromium in nickel at 1550° and at 5 pct chromium is −2200 cal per g-atom. An unusual result was obtained for iron in the form of a minimum in the experimental ln(I_Fe ^N _Ni/I_Ni ^N _Fe)-curve. Formerly Postdoctoral Fellow, Department of Metallurgical Engineering, Ohio State University, Columbus, Ohio. Formerly N. S. F. Trainee at Ohio State University.