Vector fields in a tight laser focus: comparison of models.

We assess several widely used vector models of a Gaussian laser beam in the context of more accurate vector diffraction integration. For the analysis, we present a streamlined derivation of the vector fields of a uniformly polarized beam reflected from an ideal parabolic mirror, both inside and outside of the resulting focus. This exact solution to Maxwell's equations, first developed in 1920 by V. S. Ignatovsky, is highly relevant to high-intensity laser experiments since the boundary conditions at a focusing optic dictate the form of the focus in a manner analogous to a physical experiment. In contrast, many models simply assume a field profile near the focus and develop the surrounding vector fields consistent with Maxwell's equations. In comparing the Ignatovsky result with popular closed-form analytic vector models of a Gaussian beam, we find that the relatively simple model developed by Erikson and Singh in 1994 provides good agreement in the paraxial limit. Models involving a Lax expansion introduce a divergences outside of the focus while providing little if any improvement in the focal region. Extremely tight focusing produces a somewhat complicated structure in the focus, and requires the Ignatovsky model for accurate representation.

Automated Aufbau of antibody structures from given sequences using Macromoltek's SmrtMolAntibody.

This study was a part of the second antibody modeling assessment. The assessment is a blind study of the performance of multiple software programs used for antibody homology modeling. In the study, research groups were given sequences for 11 antibodies and asked to predict their corresponding structures. The results were measured using root-mean-square deviation (rmsd) between the submitted models and X-ray crystal structures. In 10 of 11 cases, the results using SmrtMolAntibody show good agreement between the submitted models and X-ray crystal structures. In the first stage, the average rmsd was 1.4 Å. Average rmsd values for the framework was 1.2 Å and for the H3 loop was 3.0 Å. In stage two, there was a slight improvement with an rmsd for the H3 loop of 2.9 Å.