Parent Beliefs about Technology and Innovative Mathematics Instruction

Parent beliefs about roles of education, teachers, computers, and innovative mathematics instruction were examined through factor analysis. Strong relationships between parent beliefs regarding teacher and computer roles were found. The beliefs of parents about the similar roles of teachers and computers in education may impact the implementation of innovations in mathematics education and the uses of computers in education. Reciprocally, the ways computers are implemented in education may impact the beliefs parents have about the purposes of education.     

Spontaneous Metal‐Free Transfer Hydrogenation of Iminoboranes with Ammonia Borane and Amine Boranes

The first spontaneous, metal‐free, room‐temperature hydrogen transfer from ammonia borane to an iminoborane is reported. Mechanistic studies of the reaction indicate a concerted transfer of H⁺ and H^? from donor to acceptor with an activation energy far below those of comparable concerted transfer hydrogenations. This reaction was employed in the syntheses and isolation of new B,N‐disubstituted aminoboranes, a comparatively rare subset within the aminoborane family. This successful transfer hydrogenation to a highly dehydrogenated BN system may serve as a starting point for the design of new systems capable of reversible dehydrogenation/rehydrogenation.     

Performance visualization for parallel programs

Summary We describe here a set of graphical performance visualization tools that have been developed at Argonne National Laboratory for increasing one's understanding of the behavior of parallel programsThis work was supported by the Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy, under contract W-31-109-Eng-38     

Vibrational Spectroscopy As a Probe of Surface Heterogeneity: CO on NaCl(100)

The fundamental (Δv = 1 ← 0) and the first overtone (Δv = 2 ← 0) transitions of monolayer physisorbed CO on NaCl(100) single crystal surfaces at 5 K have been investigated using polarized Fourier transform infrared spectroscopy. Comparisons of the transition frequencies, bandwidths and absorbances for these two transitions together with those of dilute isotopes allow us to isolate the contribution of dynamic and static coupling effects of molecules within the monolayer. Homogeneous and heterogeneous effects can also be distinguished from band profiles of these various transitions. We conclude that the residual line broadening of 0.1 cm^?1 at 5 K for the isolated CO isotopes arises from heterogeneous surface effects. We set an upper limit of 0.07 cm^?1 for the linewidth of single CO molecules on NaCl(lOO) due to surface heterogeneity. A lower limit of × 10^?8 cm^?1 is provided by the vibrational lifetime of adsorbed CO molecules. Sharpness of the vibrational features shows that infrared spectroscopy of adsorbate is a sensitive method for probing surface and adlayer irregularities of adsorbed molecules on a single crystal.     

Analysis of Mammalian Cell Cytoplasm with Electrophoresis in Nanometer Inner Diameter Capillaries

Capillary electrophoresis in 770 nanometer inner diameter capillaries coupled to electrochemical detection with an etched electrode matching an etched capillary (etched electrochemical detection) has been used with ultrasmall sampling to inject subcellular samples from intact single mammalian cells. Separations of cytoplasmic samples taken from rat pheochromocytoma cells have been achieved. As little as 8% of the total volume of a single cell has been sampled and analyzed. Dopamine has been identified and quantified in these PC12 cells using this technique. The average cytoplasmic level of dopamine in rat pheochromocytoma cells has been determined to be 240 ± 60 μM. The use of electrophoresis in 770 nanometer inner diameter capillaries with electrochemical detection to monitor cytoplasmic neurotransmitters at the single cell level can provide information about complex cellular functions such as neurotransmitter storage and synthesis.     

The reaction of o-phenylenediamine with 3-methylglutaric anhydride

The combination of o-phenylenediamine and 3-methylglutaric anhydride in xylene as solvent produces a complex mixture of products. Isolation and characterization of four products from this reaction has shed some light on the mechanism by which 4-(2-benzimidazolyl)-3-methylbutyric acid ( 1 ) is formed under these reaction conditions.     

Phase stability of some actinides with brannerite structure at high pressures

Structure behavior of actinide brannerites ThTi₂O₆, Y_0.5U_0.5Ti_1.5Nb_0.5O₆ and their analog oxide CeTi₂O₆ was studied at high pressure by using in situ x-ray diffraction, Raman scattering and infra-red absorption techniques, respectively. Brannerite structure was found to be not stable and started to become amorphous at pressures above 20 GPa. Some minor crystalline phase(s) due to phase decomposition was observed in all the three samples during pressurization. In addition, the observed bulk modulus indicated that the actinide-bearing brannerites are more compressible than their analog compound CeTi₂O₆, which may be related to the asymmetric 5f electron orbits of actinide elements.     

Deoxygenation of Pyridones Via Their Tetrazolyl Ethers

A mild process for the conversion of pyridones to the corresponding pyridines by palladium catalyzed ammonium formate hydrogenolysis of their (1-phenyltetrazol-2-yl) ethers is described.     

High Osmolarity and L‐DOPA Augment Release via the Fusion Pore in PC12 Cells

We have amperometrically measured dopamine release from rat pheochromocytoma cells (PC12 cells) in high osmolarity conditions with and without L ‐3,4‐dihydroxyphenylalanine (L ‐DOPA) treatment. We observe an increase in the number of release events displaying a prespike feature or “foot” when the cells are stimulated in high osmolarity saline. We also see an increase in foot area and duration when cells are stimulated in high osmolarity saline, or high osmolarity saline subsequent to incubation with the dopamine precursor L ‐DOPA in isotonic saline, which serves to increase the vesicle size. The data suggest that membrane biophysics are an important component in defining the rate, duration and amount of neurotransmitter release via the fusion pore.