[Raman spectra of monkey cerebral cortex tissue].

Monkey cerebral cortex, an important part in the brain to control action and thought activities, is mainly composed of grey matter and nerve cell. In the present paper, the in situ Raman spectra of the cerebral cortex of the birth, teenage and aged monkeys were achieved for the first time. The results show that the Raman spectra for the different age monkey cerebral cortex exhibit most obvious changes in the regions of 1000-1400 and 2800-3000 cm(-1). With monkey growing up, the relative intensities of the Raman bands at 1313 and 2885 cm(-1) mainly assigned to CH2 chain vibrational mode of lipid become stronger and stronger whereas the relative intensities of the Raman bands at 1338 and 2932 cm(-1) mainly assigned to CH3 chain vibrational mode of protein become weaker and weaker. In addition, the two new Raman bands at 1296 and 2850 cm(-1) are only observed in the aged monkey cerebral cortex, therefore, the two bands can be considered as a character or "marker" to differentiate the caducity degree with monkey growth In order to further explore the changes, the relative intensity ratios of the Raman band at 1313 cm(-1) to that at 1338 cm(-1) and the Raman band at 2885 cm(-1) to that at 2 932 cm(-1), I1313/I1338 and I2885/I2932, which are the lipid-to-protein ratios, are introduced to denote the degree of the lipid content. The results show that the relative intensity ratios increase significantly with monkey growth, namely, the lipid content in the cerebral cortex increases greatly with monkey growth. So, the authors can deduce that the overmuch lipid is an important cause to induce the caducity. Therefore, the results will be a powerful assistance and valuable parameter to study the order of life growth and diagnose diseases.

[Optical limiting response in Er3+-doped TeO2-Nb2O5-ZnO glass].

Nonlinear optical properties of Er+ doped heavy metal telluride glass were studied by picosecond laser pulses. The optical limiting response was measured by a transmission technique, and the reverse saturable absorption (RSA) by a Z-scan technique. When the incident power reached the threshold, the tranmitted power did not grow rapidly with the incident power as before, but remained almost constant. It means that the Er3+ -doped glass possesses an optical limiting effect. The experimental results show that the excited absorption is responsible for the measured RSA, resulting in optical limiting response. The measured data can be well simulated by a rate equation model to obtain the absorption cross sections of the excited state.

[Micro-Raman spectra for gastritis and gastric ulcer tissues].

Micro-Raman spectroscopy was employed to identify gastritis tissues and gastric ulcer tissues. The primary spectral differences between the two types of samples include, for gastric ulcer tissues, (1) the intensity of the peak at 781 cm(-1) ascribed to cytosine decreases, while the peaks ascribed to adenine and thymine respectively at 793 and 823 cm(-1) become stronger; (2) the bands of amide I and amide III at 1654 and 1320-1270 cm(-1) respectively, characteristic of alpha-helix structural protein, lose their intensities, and the tryptophan band at 1332 cm(-1) and phenylalanine band at 1003 cm(-1) reduced significantly, while the tryptophan marker at 1554 cm(-1) up shiftes to 1556 cm(-1) with increasing intensity; (3) a blue shift of 1073 cm(-1) line, the characteristic Raman band of lipid, and a reduction in the ratio of 1303 cm(-1) assigned to in-phase CH2 twisting motion to 1268 cm(-1) from =CH in-plane deformation were observed; (4) statistic analysis shows that the ratio of Raman intensities at bands 1449 cm(-1) originating from CH2 group to 1660 cm(-1) from amide I provides a promising standard to distinguish the two tissues.

[Temporal coherent control in Er(3+)-doped telluride glass].

The authors achieved the temporal coherent control in an Er(3+)-doped telluride glass, one kind of disordered solids. The upconversion at 670 nm was modulated and the dephasing time was simulated as 300 fs. Moreover, the photon echo signal gave the dephasing time due to the phonon interaction. The agreement between the two data indicates that the interaction between the wavepacket and the phonon leads to the fast disappearance of wavepackets interference, which is helpful for the technique to be applied to the disordered solids.

[Photon avalanche upconversion in Er3+-doped telluride glass excited by 980 nm laser].

By laser excitation at the wavelength of 980 nm, efficient upconversion emission at 550 nm was observed in Er3+ doped telluride glass. The upconversion intensity varies nonlinearly with the excitation power with a threshold of 44 mW. The photon response time, of the order of tens of milliseconds, is much longer than the emission lifetimes. Moreover, the response time decreases with the increase in excitation power. The power dependence of the intensity and response time indicates that the green emission is generated through photon avalanche upconversion. Compared with 690 or 579 nm excitation wavelength, 980 nm is more efficient.

[Raman spectroscopic study of human serum albumin interacting with 3-picolylamine].

Raman spectra of human serum albumin (HSA) and HSA-3-picolylamine complex were obtained. The spectra indicate the configuration and structural transformations of HSA. The results show that the secondary structure is main alpha-helix, and the binding of 3-picolylamine doesn't change the secondary structure. However, the binding changes the configuration of disulfide bonds, transforms a single tryptophan residue from exposed tryptophan residues to hydrophobic environment, and alters the microenvironment of tyrosine.

[Anti-stokes blue fluorescence and stark splitting of 3H4 in Pr3+:Y2SiO5 (YSO)].

In the Pr3+ -doped Y2SiO5, the population in 1D2 of Pr3+ can be transferred to 3P0 state via non-radiative energy transfer by the laser excitation in resonance with 3H4-->1D2 , and we can experimentally study the Stark splitting of 3H4 energy level via 3P0 -->3H4 anti-Stokes emission spectra. Because the anti-Stokes emission spectra can avoid the energy transfer between different crystallographic site 1D2 energy levels, the above splitting lines attribution is more accurate than the assignment via 1D2-->3H4 Stokes spectra by the laser excitation in resonance with 3H4-->1D2. In addition, the character of the anti-Stokes fluorescence decay time was observed.