The influence of aqueous content in small scale salt screening--improving hit rate for weakly basic, low solubility drugs.

Salt screening and selection is a well established approach for improving the properties of drug candidates, including dissolution rate and bioavailability. Typically during early development only small amounts of compound are available for solid state profiling, including salt screening. In order to probe large areas of experimental space, high-throughput screening is utilized and is often designed in a way to search for suitable crystallization parameters within hundreds or even thousands of conditions.

Interlaced optical force-fluorescence measurements for single molecule biophysics.

Combining optical tweezers with single molecule fluorescence offers a powerful technique to study the biophysical properties of single proteins and molecules. However, such integration into a combined, coincident arrangement has been severely limited by the dramatic reduction in fluorescence longevity of common dyes under simultaneous exposure to trapping and fluorescence excitation beams. We present a novel approach to overcome this problem by alternately modulating the optical trap and excitation beams to prevent simultaneous exposure of the fluorescent dye.

Cavity ringdown strain gauge.

Biconical tapered single-mode fiber, which is common in many telecommunications components, offers an alternative sensor to typical optical fiber strain gauges that are susceptible to temperature and pressure effects and require expensive and sophisticated signal acquisition systems. Cavity ringdown spectroscopy, a technique commonly applied to high-sensitivity chemical analysis, offers detection sensitivity advantages that can be used to improve strain measurement with biconical tapers. Combining these two technologies in a spatially extended resonator, we demonstrate a minimum detectable change in ringdown time of 0.

Trace moisture detection using continuous-wave cavity ring-down spectroscopy.

We have developed an instrument to measure trace concentrations of small hydride species in gases using continuous-wave cavity ring-down spectroscopy with near-infrared diode laser excitation. An rms baseline equivalent absorbance of 9.2 x 10(-11) cm(-1)/square root(n) is found, where n is the number of ring-down transients.