Dual-wavelength Nd:YAG laser operation at 1319 and 1338 nm by direct pumping at 885 nm.

This paper presents a continuous wave and a Q-switched Nd:YAG laser pumped by diode laser at 885 nm. The maximum output power of the CW laser is 8.28 W with an absorbed slope efficiency of 35.01%. The Q-switching is achieved using a V³âº:YAG crystal as the saturable absorber. The maximum output power of the passively Q-switched laser is 3.55 W with an absorbed pumping power of 28.65 W operated with a dual wavelength at 1319 and 1338 nm. The shortest pulse widths of the Q-switched laser are 20.20 and 20.86 ns, with a maximum repetition rate of 64.10 kHz.

[Application of wavelet transform to the infrared diffusion reflectance spectrum of rocks].

The infrared diffuse reflectance spectra of hydrocarbon source rocks with different particle sizes were measured. The result indicated that the absorbency of the raw spectrum decreased with the reduction of particle size, but the relationship turned to be reverse after we pretreated the original spectra by using wavelet transform to eliminate the background and calibrate the baseline drift, both of which were caused by scattering. The reversed relations showed that the spectral lines were influenced deeply by the scattering of the samples. So the particle size of the samples to be measured and the particle size of the model samples must be consistent to reduce the error. The low frequency part of the spectrum filtrated by wavelet transform corresponds to the scattering, and the authors used it to set up a model at the latent absorbance wave number (near 2 820 cm(-1)) to forecast the particle size. By comparing this model with the other model based on the original spectrum the authors found that the pertinence of the anterior model is higher than the latter one and the value reaches 0.999 7. So the authors can accurately forecast and control the distribution of the particle size by this model, which can be used to improve the accuracy in the quantitative analysis of the infrared reflectance spectrum. Also the study validated that both scattering and absorption coefficients are inversely correlated with the particle size.

Synthesis and biological evaluation of novel tanshinone IIA derivatives for treating pain.

Due to ineffectiveness and side effects of existing analgesics, chronic pain has become one of the most complex and difficult problems in the clinic. Monoacylglycerol lipase (MAGL) is an essential hydrolase in the endocannabinoid system and has been identified as a potential target for the treatment of pain. In the present study, we designed and synthesized twelve tanshinone IIA analogs and screened their activity against MAGL. Selected compounds were tested for analgesic activity in vivo, with the acetic acid writhing test model. Among the test compounds, compound III-3 (IC50 120 nmol·L-1) showed significant activity against MAGL and ameliorated the clinical progression in the mouse pain model. Additionally, compound III-3, substitution with N-methyl-2-morpholinoacetamide, demonstrated improved solubility relative to tanshinone IIA.

[Surface-enhanced Raman spectra of oxidation damnification of fetal bovine serum by ozone].

Fetal bovine serum was treated by ozone for 1 hour and 3 hours before getting its surface-enhanced Raman spectra from 200 to 1 800 cm(-1). Treated with ozone for 1 hour, it shows a significant decrease in band intensity. Treated with ozone for 3 hours, the band intensity has a further decrease but not so obviously, which means that oxidation of ozone is short lived. Treated with ozone, the orderly conformations of main chains in protein such as alpha-helix, beta-sheet and beta-corner are damaged seriously. Aromatic side chains and C-S of Cys and Met also are damnified greatly. All this means that strong oxidation of ozone results in denaturation, conformational changes and even degradation in protein.

[The orthogonal polynomial regression method of multi-wavelength radiation thermometry].

For the problem of multi-wavelength radiation thermometry, the traditional data processing methods are the least squares techniques, the multiple linear regression fitting, and the stepwise regression fitting. There are some shortages in these methods, resulting in a certain error between the fitting result and the true temperature of the object surface. A new data processing method of multi-wavelength radiation thermometry--the orthogonal polynomial regression method was brought forward in this article on the base of variable emissivity. The mathematic principle of orthogonal polynomial regression method was expounded and according to the surface emissivities of tungsten, the true temperature of tungsten surface was simulated by the stepwise regression method and the orthogonal polynomial regression method. By comparing the fitting results, the authors found that the orthogonal polynomial regression method has the merit of simple principle and small operation, and the relative error between the fitting result and the surface true temperature is smaller. So the authors can draw the conclusion that using the orthogonal polynomial regression method to process the data of the multi-wavelength radiation thermometry, the fitting result has smaller error, it can fit the true temperature of object faster, and the result is more accurate than the traditional data processing methods.