Abstract: A system and method non-invasive biomedical optical imaging and spectroscopy with low-level light is described. The technique consists of a modulated light source (120) coupled to tissue (100) of a patient to introduce excitation light. Fluorescent light emitted in response to the excitation light is detected with sensor (148). The AC intensity and phase of the excitation and detected fluorescent light is provided to a processor (160) operatively coupled to sensor (148). Processor (160) employs the measured re-emission kinetics of excitation and fluorescent light to "map" the spatial variation of one or more fluorescence characteristics of the tissue (100). The fluorescence characteristic may be provided by exogenous contract agents, endogenous fluorophores, or both. The variation is determined by solving frequency domain diffusion equations at a number of designated points in the tissue as part of a recursive estimation algorithm.

Abstract: Disclosed are processes for pretreating cellulosic materials in liquid water by heating the materials in liquid water at a temperature at or above their glass transition temperature but not substantially exceeding 220.degree. C., while maintaining the pH of the reaction medium in a range that avoids substantial autohydrolysis of the cellulosic materials. Such pretreatments minimize chemical changes to the cellulose while leading to physical changes which substantially increase susceptibility to hydrolysis in the presence of cellulase.

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.