able for the more unusual geometries of some biological particles. Nevertheless, good approximations can often be made as demonstrated by the excellent results of Latimer and co-workers ~ in their scattering calculations for some highly complex turbid suspensions (yeast cells, chloroplasts, bacteria, etc.). The meaningful extension of circular diehroism and optical rotatory dispersion methods t...

The crucial test regarding the usefulness of the optical rotatory dtspersion method for the study of protein conformation was in confronting the results of this method w&the x-ray structural analysis of myoglobm. The high resolution x-ray structural analysis of Kendrew et al. on myoglobin crystals (1) and the optical rotation studies of Beychok and Blout (2) and Urnes, Imahori, and Doty (3) on ...

Optical tweezers are microscopic tools with extraordinary precision in the determination of the position (±2 nm) of a colloid (diameter: ∼2.0 μm) in 3D-space and in the measurement of small forces in the range between 0.1 and 100 pN (pN=10-12 N). Experiments are reported in which single double-stranded (ds)-DNA chains of different length [2,000 base pairs (bp), 3,000, 4,000, and 6,000 bp] are s...

Coupled cluster (CC) and density-functional theory (DFT) calculations of optical rotation, [alpha](lambda), have been carried out for the difficult case of (S)-methyloxirane for comparison to recently published gas-phase cavity ringdown polarimetry data. Both theoretical methods are exquisitely sensitive to the choice of one-electron basis set, and diffuse functions have a particularly large im...

Optical tweezers have broad applications in studies of structures and processes in molecular and cellular biophysics. Use of optical tweezers for quantitative molecular-scale measurement requires careful calibration in physical units. Here we show that DNA molecules may be used as metrology standards for force and length measurements. Analysis of DNA molecules of two specific lengths allows sim...

Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on...

With the development of optical coherence tomography, the application optical coherence elastography (OCE) has gained more and more attention in biomechanics for its unique features including micron-scale resolution, real-time processing, and non-invasive imaging. In this review, one group of OCE techniques, namely dynamic OCE, are introduced and discussed including external dynamic OCE mapping...