Signals Analysis and Clinical Validation of Blood and Oxygen Data in Human Brain

With a self-made near-infrared analytical instrument to blood and oxygen parameters in human brain, 80 cases in which 20 are healthy persons and 30 are anaesthetised cases and others are patients with heart function lack is taken to examine, and the data of blood and oxygen in brain tissue were collected and analyzed by the method of power spectrum and correlation function. The results indicate that: (1) The average brain oxygen saturation of healthy persons and anaesthetised cases is about 80%, in accord with normal parameter of physiology. Contrastively, the average brain oxygen saturation of patients with heart function lack is 72.8%, which is obviously less than that of healthy persons and anaesthetised cases. The probability of medical statistics is less than 0.01. (2) The shapes of wave of brain blood and oxygen for the healthy person and the anaesthetised case reveal small periodical fluctuations with stable shape and base line, and the trend of increase or decrease of blood and oxygen parameters in brain tissue is synchronous and a phase reversal, but for the patient with heart function lack in a brain oxygen lack state, the shapes of wave are irregular. This is a hint that near infrared light passing through tissue can reflect the intuitionistic change of brain blood and oxygen parameters.(3) The power spectra of brain blood and oxygen for the healthy person and the anaesthetised case has a clear main peak, narrow bandwidth and perfect superposition each other, but the power spectra for the patient with heart function lack in a brain oxygen lack state is on the contrary.(4) The average cross correlation coefficient of brain blood and oxygen for healthy persons and anaesthetised cases is -0.9825±0.1027 close to -1. But the average cross correlation coefficient for patients with heart function lack in a brain oxygen lack state is merely -0.8923±0.1035 which is obviously greater than -1 and the probability of medical statistics is less than 0.01. The clinic experiments have proved that the shapes of waves, the power spectrum and cross correlation coefficient of brain blood and oxygen are useful to analyze the physiological status and changes of blood and oxygen in human brain.

Effect of Fe concentration on the nonlinear refraction and reverse saturable absorption in ferroelectric X-cut LiNbO_3 crystal

In this Letter, the effects of the iron （Fe） dopant concentration on the nonlinear optical properties of iron-doped ferroelectric X-cut LiNbO3 crystals plates are studied by using the Z-scan technique with a cw laser at the wave- length of 532 nm. The amount of iron in the compound is varied from 0 to 0.15 mol%. Measurements of nonlinear refractive index n2 and the nonlinear absorption coefficient β are determined. The sign of the nonlinear refractive index is found to be negative and the magnitude is on the order of 10-s cm2/W. This nonlinear effect increases as the concentration increases from 0 to 0.15 mol%. A good linear relationship is obtained between nonlinear refractive index, nonlinear absorption coefficient, and concentration.

The gelation rule of the polyol acetal derivatives in binary solvent mixtures

The gelation properties of polyol acetal derivatives including 2,4-（3,4-dichlorobenzylidene）-D-sorbitol（DCBS）, 1,3：2,4-di（3,4-dichlorobenzylidene）-D-sorbitol（DDCBS） and 1,3：2,5：4,6-tris（3,4-dichlorobenzylidene）-D-mannitol（TDCBM） in 35 single solvents and 39 binary solvent mixtures have been studied. FTIR and XRD results suggest that the self-assembly patterns of the gelator will not change in either the single solvent component or the corresponding solvent mixtures, but the critical gelation concentration（CGC）will be influenced. The results of SEM and rheology showed that the formation of true gels at saturated concentrations. Improving the heating temperature may promote the dissolving of gelators which are even insoluble at the temperature of the solvent boiling point and change the gelation behaviors. FloryHuggins parameter（x） was used to predict the gelation behavior of DCBS in the mixed solvents, and it is shown that the x values for the mixed solvents that can be gelled by DCBS are either greater or smaller than those for the selected good solvents.