We report the discovery of a new gravitationally lensed radio source. Radio maps of MG 0751+2716 show four lensed images, which, at higher resolution, are resolved into long arcs of emission. A group of galaxies is present in optical images, including the principal lensing galaxy, with a much brighter galaxy just a few arcseconds away. We have measured the redshift of this brighter galaxy. No optical counterpart to the background source has been detected. Lens models that can readily reproduce the lensed image positions all require a substantial shear component. However, neither the very elongated lens nor the bright nearby galaxy are correctly positioned to explain the shear. Lens models which associate the mass with the light of galaxies in the group can produce an acceptable fit, but only with an extreme mass-to-light ratio in one of the minor group members.

Electroporation is believed to involve a temporary structural rearrangement of lipid bilayer membranes, which results in ion and molecular transport across the membrane. The results of a quantitative study of molecular transport due to electroporation caused by a single exponential pulse are presented; transport of four molecules of different physical characteristics across erythrocyte ghost membranes is examined as a function of applied field strength. Flow cytometry is used to quantitatively measure the number of molecules transported for 10(4) to 10(5) individual ghosts for each condition. This study has four major findings: 1) Net transport first increases with field strength, but reaches a plateau at higher field strengths. Significant transport is found at or below 1 kV/cm, and transport plateaus begin at field strengths between 2 and 5 kV/cm depending on the molecule transported. 2) A single population of ghosts generally exists, but exhibits a wide distribution in the amount of molecular transport. 3) Under the conditions used, the direction of transport across the ghost membrane does not appear to affect molecular transport significantly. 4) Large numbers of ghosts may be destroyed by the electroporation procedure.

We are interested in using SU-8 dense gratings with very high aspect ratio microchannels as the master mold for fabrication of child molds needed for replication. For such applications, the sidewall taper angle and mask replication fidelity of SU-8 are very important. Increasing the exposure time was experimentally observed to decrease the width of the microchannel and the sidewall angle of SU-8 bars. A new diffraction-refraction-reflection model was also developed. The calculated microchannel width and sidewall angle at high exposure dose agreed well with the experimentally observed values indicating that reflection at the silicon substrate was significant. The larger than calculated actual microchannel width for low exposure dose was shown to be due to leaching of unreacted SU-8 in the developer. Dense gratings of high aspect ratio SU-8 bars separated by high aspect ratio (19.1) microchannels were also demonstrated.

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