Creating permanent 3D arrangements of isolated cells using holographic optical tweezers

We report the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within a solution comprising monomer precursors. The matrix was then set and after the laser beam was removed, we were able to demonstrate that the structures remained intact for many days. We were also able to demonstrate that, in the presence of appropriate nutrients, the E. coli survived within the gelatin matrix for several days. The technique could have a number of potential future applications, including the arrangement of a variety of different cell types in complex architectures, as motifs for promoting tissue differentiation and growth within the field of cell engineering.     

An alternative preparation of the 2-dimethylaminomethylene-1,3-bis(dimethylimmonio)propane salt from phosphonoacetic acids and some applications in heterocyclic synthesis

An alternative preparation of a 2-iminovinamidinium salt from phosphonoacetic acids is described along with its application to the synthesis of 5-formylpyrimidines and masked 4-formylpyrazoles.     

Magnetic splitting of optical phonons in cubic dysprosium aluminum garnet

The magnetic splitting of triply degenerate (T _2g )-phonons in the cubic Rare Earth compound dysprosium-aluminum-garnet could be observed making use of the polarization properties of the Raman-effect.The theoretical predictions of a phenomenological symmetry analysis are compared to a more detailed microscopic treatment of the observations in terms of the magnetoelastic interaction.     

Biorthonormal electronic basis sets in the theory of electron transfer reactions

We have used the quantum-chemical concept of biorthonormal electronic basis functions to derive the two-centre electron exchange integrals in non-diabatic electron transfer reactions. It is shown that only non-diagonal parts induce the transfer corresponding to inclusion of the diagonal parts in the zero-order hamiltonians. This result coincides with the result derived previously by means of scattering theory.     

Stereochemistry of substitution at tricovalent phosphorus

Reactions of one diasteveomer of a XP-NMe₂ compound ($\text{1a}$) with alcohols, phenol and amines have been shown by NMR to proceed uith initial inversion at phosphorus, but the overall reactions are not stereoselective.     

A rapid procedure for obtaining hydrodynamic voltammetry plots for electrochemical detectors in high-pressure liquid chromatography systems

The construction of relatively simple and inexpensive apparatus for the determination of the operating conditions for electrochemical detectors in high-pressure liquid chromatography systems is described. A procedure has been developed for the characterization of electrochemically active compounds.