ABSTRACT
Simple modifications to the Sayre squaring method determine a class of functional atomic form constraints representing the likelihood that a particular atomic form occupies a localized volume of the unit cell. The functional formulation, as opposed to the traditional structure-factor equation formulation, facilitates modeling multiple atom types and integrating atomic form information into established density-modification routines. Two complementary methods of phase refinement are considered. The first method constructs an atomic resolution probabilistic filter from the atomic form functions. The probabilistic filter is used to modify density throughout the unit cell, in both the solvent and macromolecular regions of the unit cell. The second method exploits the automated map interpretation aspects of the atomic form functions. A simple iterative phase-refinement procedure alternating the two methods successively is applied to three small metalloproteins, with significant phase improvements beyond that obtained with conventional density modification or refinement in accordance with reciprocal-space squaring equations.
ABSTRACT
Eighty-five patients referred to the Women's Cancer Center, University of Minnesota had transvaginal color flow Doppler performed to determine if pelvic malignancy could be predicted by blood flow assessment. Their mean age was 49 years (range 21-86 years). Thirty-five patients were subsequently found to have malignant tumors of the cervix, uterus or ovary. The presence of increased intratumoral blood flow as depicted by color flow Doppler had a sensitivity of 83%, specificity of 100%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 89% for malignancy. The mean intratumoral Pulsatility Index (PI) of the patients with malignant tumors was 0.81 (SD 0.24; range 0.3-1.2), which was significantly lower than for the benign group (P = 0.001). A PI of
