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The undamaged and damaged areas of the ITO thin film deposited on a silicon substrate induced by laser with different energies were tested with the transmission terahertz time-domain spectroscopy system. Their time-domain spectra and frequency-domain spectra of 0.4–1.0 THz were obtained, and the differences were analyzed between the undamaged and damaged areas in these two spectra. The results show that the peak-to-peak value in the time domain and the amplitude in the frequency domain of the damaged area evidently increased compared with those of the undamaged area, and with the increase in laser-induced energy, resulting in the larger damaged area and heavier surface roughness, these two parameters gradually decrease. For the damaged area of the ITO thin film with the undamaged substrate, the refractive index and absorption coefficient are lower than those of the undamaged area. Therefore, the variation in the terahertz time-domain and frequency-domain spectra could be utilized to distinguish the damage of the optical thin film irradiated by laser, which provides a new approach for the laser-induced damage identification and the technical support in effect of the laser-induced damage on the properties of the optical thin film element in the terahertz band.

K9 glass is an important optical element of the high energy laser system. In an attempt to investigate the variation of optical properties of K9 glass before and after laser induced damage, based on the transmission terahertz time-domain spectral system, the undamaged and the damaged K9 glasses induced by laser were tested to obtain the terahertz time-domain and frequency-domain spectra and the refractive index and absorption coefficient of the samples were calculated in terahertz band for further analysis. Results show that with the increase of laser energy, from the undamaged to the damaged K9 glasses to different extent, the peak to peak value in time domain and the amplitude value in frequency domain present a decreasing trend in varying degrees, and in the 0.4 ∼ 0.5 THz band, the absorption coefficient increases continuously with a slight change of refractive index, which indicates that K9 glass not only appears the melting and fracture in the macroscopic morphology after laser-induced damage, but also forms non-bridged oxygen atoms in its microstructure with more ion bonds and free electrons and the change of ion polarization. In this regard, this paper provides a technical basis for exploring the micro characteristics of K9 glass after laser-induced damage, and lays a good foundation for the application of terahertz time-domain spectroscopy to laser-induced damage analysis.

Tumor development is associated with the methylation of cytosine-guanine (CpG) islands. The occurrence of methylation requires several factors, such as DNA methylation systems and polycomb group (PcG) proteins. At present, novel drugs are needed for the treatment of chronic myeloid leukaemia (CML), particularly considering the current prognosis of CML. The methylation status of the Src homology 2 domain-containing tyrosine phosphatase 1 (SHP1) gene, a negative regulator of signal transduction, has been identified as being altered in numerous haematological malignancies. DNA methyltransferase 1 (DNMT1) and the PcG protein complex member enhancer of zeste homolog 2 (EZH2) participate in a number of gene methylation processes. The present study investigated the methylation status of the SHP1 gene in CML, and examined the association between DNMT1 and EZH2 activity and the SHP1 gene methylation status to develop novel strategies for the treatment of CML. The results revealed that SHP1 gene methylation status was altered during the progression of CML. These data indicated that SHP1 gene methylation is associated with the progression of this disease. The associations of DNMT1 and EZH2 activities with the methylation status of the SHP1 gene were additionally investigated via chromatin immunoprecipitation. DNMT1 and EZH2 were revealed to be bound to the promoter region of the SHP1 gene, and were involved in the process of SHP1 methylation. Furthermore, DNMT1 and EZH2 were associated with disease progression. Thus, the findings of the present study suggest a new target for the treatment of CML, particularly for future drug development. [ABSTRACT FROM AUTHOR]