Controlled manipulation of molecular samples with thenanoManipulator

The nanoManipulator system adds a virtual-reality interface to an atomic-force microscope (AFM), thus providing a tool that can be used by scientists to image and manipulate nanometer-sized molecular structures in a controlled manner. As the AFM tip scans the sample, the tip-sample interaction forces are monitored, which, in turn, can yield information about the frictional, mechanical, material, and topological properties of the sample. Computer graphics are used to reconstruct the surface for the user, with color or contours overlaid to indicate additional data sets. Moreover, a force feedback stylus, which is connected to the tip via software, allows the user to directly interact with the macromolecules. This system is being used to investigate carbon nanotubes, DNA, fibrin, adeno- and tobacco mosaic virus. It is now also possible to insert this system into a scanning electron microscope which provides the user with continuous images of the sample, even while the AFM tip is being used for manipulations     

Ferroelastic domains and phases in ferromagnetic nanostructured FePd alloy

Polarization optical, electron microscopic, and thermomagnetic investigations of FePd single crystals undergoing an A1 → L1₀ phase transformation have been carried out. The results obtained have been analyzed proceeding from the concept of ferroelasticity and the experimental criteria of its existence. The features of phase transformations in equiatomic FePt and FePd alloys have been compared. A conclusion has been drawn that the atomic ordering in the FePd alloy is preceded by the formation of a ferroelastic lowsymmetry disordered (BCT) phase, and the A1 → L1₀ phase transformation presents a combination of different types of phase transitions such as cooperative displacement and ordering of atoms.     

Sensitivity to ethanol-induced motor incoordination in 5-HT1B receptor null mutant mice is task-dependent: Implications for behavioral assessment of genetically altered mice.

Neuromuscular impairment by ethanol likely involves complex effects on balance, gait, muscle strength, and other features of motor coordination. The present experiments showed that relative sensitivity to ethanol-induced motor impairment in serotonin 1B (5-HT1B) null mutant and control mice was task dependent. We found that ethanol-treated null mutant mice made fewer missteps on a balance beam than did ethanol-treated wild-type mice, and confirmed a previous finding of their lesser ethanol sensitivity in the grid test. The genotypes did not differ in ethanol sensitivity as measured by the screen test, static dowel, fixed-speed rotarod, accelerating rotarod, grip strength, or loss of righting reflex tests. These experiments suggest that within a behavioral domain, alternative tests of function are not equivalent, so multiple assessment tools should be used to avoid misinterpretation of gene function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fractal basis functions and the CVBEM

The Complex Variable Boundary Element Method or CVBEM has recently been applied to the use of new fractal basis functions for defining a global trial function on the problem domain. In that recent advance, a topic for future research was the need for development of an algorithm to construct a global trial function that converges to the true problem boundary conditions, assumed to be continuous on the boundary. In this paper, such an algorithm for constructing a sequence of fractal basis functions is presented.     

Preparation of aqueous polyaniline dispersions by micellar‐aided polymerization

Polyaniline (PAn) dispersed in water was prepared with sodium dodecylsulfonate (SDS) as a surfactant with varying concentrations of aniline and HCl and molar ratios of SDS/aniline. The PAn dispersion was homogeneous and stable, and its pH value could be adjusted. The conductivity of PAn powder, precipitated from this dispersion, was as high as 20 S/cm. The transmission electron microscopy morphology of PAn assembled in the dispersion was particle‐like, fiber‐like, or coil‐like, depending on the initial concentration of SDS and aniline. The polymerization of aniline was accelerated by SDS, which was confirmed by open‐circuit potential measurement during the polymerization process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1550–1555, 2003     

Adsorption of Dispersants on Zirconia Powder in Tape-Casting Slip Compositions

This paper reports the extension of the more fundamental work of Tormey et al. on the effectiveness of a common dispersant (menhaden fish oil) and a model system (glycerol trioleate) to tape-casting slip formulation. The adsorption isotherms of the two adsorbates on doped zirconia from methyl ethyl ketone—ethanol solutions were measured by thermogravimetric analysis of solutions equilibrated with the powder surface. Viscosity decreased while sintered density increased in tape-cast samples prepared to dispersant concentrations corresponding to points along the adsorption isotherm in a way which follows the isotherm if binder competition for surface sites is considered.