We observed that flowing helium at moderate pressures accelerated DNA-coated microprojectiles to velocities suitable for penetration of cells in intact plant tissues. The flowing helium principle permitted the construction of a simple and inexpensive transformation device that was easier to use than those previously described. This device provided efficient transformation of cells in soybean seedlings and other plants.

The structure of hexagonal CaALSieOs has been determined by two-dimensional Fourier methods. Double sheets of composition A12Si~O s are made up of linked oxygen tetrahedra about (Si, A1) atoms. They are similar to the sheets found in hexagonal BaAleSi~.O s, but are considerably deformed from hexagonal to trigonal symmetry, in such a way as to contract the cationic niches between the sheets. A comparison of the two structures illustrates the non-rigidity of the anionic layers.Diffuse streaks on the Weissenberg photographs indicate mistakes in the stacking of the sheets. Such mistakes lead to the formation of trigonal prisms of oxygen atoms around calcium atoms, whereas in the ordered structure calcium is coordinated octahedrally. The Ca-O distance is found to be 2.39 /~ in either coordination. The (Si, A1)-O distances are 1.66 and 1.71, both -t-0.03 /~. The residual, R = 13.8%, refers to the 151 permitted non-equivalent reflections in the Cu Ka sphere, 49 of which are structurally absent.

Natural convection heat transfer from a vertical cylinder in liquid sodium was experimentally studied. Two test cylinders of different dimensions were used. They were 7.62 and 17.51 mm in diameter, and 186 and 257 mm in heated length, respectively. The surface heat flux was ranged from 2×10 4 to 2×10 6 W/m 2 at the bulk liquid temperatures of 673, 773 and 873 K. The local heat transfer coefficients on the cylinders were obtained systematically at various heights, x, from the leading edge of the heated section. On the other hand, theoretical equations for laminar natural convection heat transfer from a vertical cylinder were numerically solved by using PHOENICS code for the same conditions as the experimental ones considering the temperature dependence of thermo-physical properties concerned. with the deviations less than 20 % for the range of R f tested here. The Nu x on the rod diameter of a heat exchanger for a power plant, D=31.8 mm, were numerically analyzed by using this code. A correlation, which can describe the effects of the cylinder diameter and the cylinder height, was given based on the experimental and theoretical values. This correlation can describe the experimental and theoretical values of Nu x for R f ranging from 1.5×10 2 to 4.7×10 6 within 20 % difference.

We report that the reductive cyclization of o-nitroarylamine with aldehyde using sodium dithionite (Na2S2O4) could be accelerated by addition of H2O, which made it possible to control the heat release of the reaction by semibatch-type operation. Safety evaluation was performed using DSC, ARSST, in situ IR analysis, and Multimax.