Half sphere exposure used in predicting discontinuous B-cell epitopes. Song et al. have developed an online webserver termed HSEpred to predict half-sphere exposure from protein primary sequences. HSEpred server can achieve the correlation coefficients of 0.72 and 0.68 between the predicted and observed HSE-up and HSE-down measures, respectively, when evaluated on a well-prepared non-homologous protein structure dataset. Moreover, residue contact number (CN) can also be accurately predicted by HSEpred webserver using the summation of the predicted HSE-up and HSE-down values, which has further enlarged the application of this new solvent exposure measure. Recently, Heffernan et al. has developed the most accurate predictor for
Sphere and is called the equation of an imaginary sphere. If formula_5 the only solution of formula_6 is the point formula_7 and the equation is said to be the equation of a point sphere. Finally, in the case formula_8, formula_6 is an equation of a sphere whose center is formula_10 and whose radius is formula_11. If in the above equation is zero then is the equation of a plane. Thus, a plane may be thought of as a sphere of infinite radius whose center is a point at infinity. The points on the sphere with radius formula_12 and center formula_13 can