[The Enhancement Research of Magnetic Stirring with Laser Irradiation Aqueous Solution on ICP Source Radiation].

At present, the way to introduce the sample into the inductively coupled plasma atomic emission spectrometry (ICP-AES) light source is still in the form of solution. In order to improve the treatment effect of the aqueous solution and change its physical properties, the surface tension and viscosity under different experimental conditions were measured with magnetic stirring combined with laser irradiation. . The treated samples were introduced into the inductively coupled plasma (ICP) to measure the spectral line intensity, signal-to-background ratio, excitation temperature and electron density emitted by the ICP source. The experimental results showed that: when the magnetic stirrer rotate speed was 1 197 r·min-1, the laser power density was 0.227 6 W·cm-2 and irradiation for 15 min, the surface tension and viscosity of the solution were decreased by 27.85% and 8.66% respectively than those of the untreated solution. As to the element spectral lines of As 188.980 nm, Cd 214.439 nm, Cr 267.716 nm, Cu 324.754 nm, Hg 253.652 nm and Pb 220.353nm: the intensity was enhanced 32.07%, 65.36%, 18.27%, 32.29%, 19.38% and 54.28%; the signal-to-background ratio increased by 25.13%, 60.97%, 18.18%, 27.69%, 21.11% and 48.93%, respectively. The enhancement of the plasma radiation was explained to a certain extent by measuring the excitation temperature and electron density of the plasma. The processing method of the aqueous solution can effectively improve the spectral intensity and signal-to-background ratio of the ICP. Compared with the laser irradiation aqueous solution separately, this method significantly shortened the processing time, improve the efficiency. This method is simple, with no secondary pollution in the treatment of the sample solution, convenient popularization and use.

[Enhancement effect of double-beam laser processed aqueous solution on ICP emission spectrum].

In order to change the physical properties of aqueous solution and improve the radiation intensity of the ICP emission spectrum, the effects of different laser power density and irradiation time on the surface tension and viscosity of aqueous solution were investigated by using near infrared laser at 976 nm and CO2 laser at 10. 6 µm to irradiate aqueous solution orthogonally, then the enhancement of ICP spectral intensity with processed solution was discussed. The results showed that the surface tension and viscosity of aqueous solution reduced by 42. 13% and 14. 03% compared with the untreated, and the atomization efficiency increased by 51.26% at the laser power density 0. 265 7 W . cm-2 of 976 nm and 0. 206 9 W . cm-2 of CO2 laser with 40 min irradiation time. With the optimized aqueous solution introduced into the ICP source, the spectral line intensity of sample elements As, Cd, Cr, Hg and Pb was enhanced by 46.29%, 94. 65%, 30. 76%, 33.07% and 94. 58% compared to the untreated aqueous solution, while the signal-to-background ratio increased by 43. 84%, 85. 35%, 28. 71%, 34. 37% and 90. 91%, respectively. Plasma temperature and electron density also increased by 5. 94% and 1. 18% respectively. It is obvious that the method of double-beam laser orthogonal irradiation on solution can reduce the surface tension and viscosity of aqueous solution significantly, and raise the radiationintensity of ICP source, and will provide a better condition for detecting the trace heavy metal elements in water samples.

[Study of self-absorption effect on laser-induced metal plasma].

In order to reduce the effect of the spectral line self-absorption on the analysis result in the laser induced plasma and enhance the qualities of spectrum, the spectral information was recorded by the spectral analysis system consisting of a modular multifunctional grating spectrometer and a CCD detector etc., and the electron temperature and electron density of the plasma were measured with the spectroscopic methods. A plane mirror device was used to constraint the laser plasma, and a reasonable explanation was got through comparing the linear evolution under different experimental conditions and measuring the temperature, electronic density and sample evaporation. The result shows that when an appropriate plane mirror device was used to constraint the laser plasma, the axial temperature of the plasma increased and the radial distribution of the plasma becomes uniform; the electron density increased dramatically; however, obviously sample evaporation decreased, which may be the reasons for being able to effectively reduce the level of self-absorption spectral lines. Therefore, the plane mirror device could reduce the self-absorption effect in the laser-induced plasma. This makes it possible to choose a sensitive line that acts as analysis line in the quantitative analysis of the major elements. In other words, this promotes the measurement precision in the laser-induced break-down spectroscopy.

[Enhancement effect of laser-processed aqueous solution on ICP source radiation].

To enhance the intensity of inductively coupled plasma-atomic emission spectrum and improve the detection level of trace heavy metal elements, the surface tension and viscosity of the aqueous solution processed by near-infrared laser at wave-length of 976 nm were studied in the present paper. The influences of the treated solution on the spectral line intensity and signal-to-background ratio of the ICP source were observed. The results showed that when the laser irradiation time was 60 min and the power density was 0.329 6 W x cm(-2), the surface tension and viscosity of the solution decreased by 36.73% and 9.73% respectively compared to the untreated solution. Under the optimum conditions, the aqueous solution treated by the laser irradiation was introduced into the ICP source. By measuring the intensity of emission spectrum of the sample elements, the spectral line intensity of Cd, Cr, Cu, Hg, and Pb was enhanced by about 73.52%, 22.97%, 33.86%, 24.44% and 65.59% compared to the untreated solution, while the signal-to-background ratio increased by 76.03%, 21.74%, 32.17%, 22.68% and 65.32%, respectively. Spectral line intensity and signal-to-background ratio of the ICP source were significantly improved so that the foundation was established for reducing the analysis detection limits. Further more, the surface tension and viscosity of the processed aqueous solution remain the same within 30 minutes standing time with the stable physical properties. This simple and easy method of laser-processed aqueous solution helps improve the detection capabilities of ICP spectrometry.

[Effect of flat-mirror device on laser-induced plasma radiation characteristics].

To improve the quality of laser-induced breakdown spectroscopy, flat-mirror device was proposed. The effects of flat-mirror device on the radiation characteristics of laser-induced plasma were studied. The experimental results showed that when the device consisted of three flat-mirrors placed around the plasma, the spectral line intensity of Mg, Fe, Ba, Ti and Al increases by about 116.2%, 96.43%, 90.93%, 102.1% and 98.57% than that without flat-mirror device, and the signal-to-noise raises by around 39.17%, 32.48%, 38.07%, 39.95% and 21.30%,respectively. By measuring the plasma parameters, the mechanism of the radiation enhancement obtained with the device consisting of three flat-mirrors was explained. This method was an effective way to improve the detection capacity of LIBS.

Enhancement effects of flat-mirror reflection on plasma radiation.

Laser-induced breakdown spectroscopy quality can be improved by using a nanosecond Nd:YAG laser pulse to excite soil samples. To investigate how flat-mirror reflection affects the radiation characteristics of laser-induced plasma, emission spectra of sample elements were recorded using a grating spectrometer and photoelectric detection system. Placing a planar mirror vertically on the sample surface (10 mm mirror to plasma-center axis distance) for flat-mirror reflection increased spectral line intensities of Mg, Al, Fe, and Ba by 93.06%, 159.63%, 93.43%, and 94.61%, respectively. Signal-to-noise ratio increased by 17.56%, 40.21%, 31.29%, and 30%. The radiation enhancement mechanism was clarified using measured plasma parameters.

Four microRNAs promote prostate cell proliferation with regulation of PTEN and its downstream signals in vitro.

BACKGROUND: Phosphatase and tensin homologue (PTEN), as a tumor suppressor, plays vital roles in tumorigenesis and progression of prostate cancer. However, the mechanisms of PTEN regulation still need further investigation. We here report that a combination of four microRNAs (miR-19b, miR-23b, miR-26a and miR-92a) promotes prostate cell proliferation by regulating PTEN and its downstream signals in vitro. METHODOLOGY/PRINCIPAL FINDINGS: We found that the four microRNAs (miRNAs) could effectively suppress PTEN expression by directly interacting with its 3' UTR in prostate epithelial and cancer cells. Under-expression of the four miRNAs by antisense neutralization up-regulates PTEN expression, while overexpression of the four miRNAs accelerates epithelial and prostate cancer cell proliferation. Furthermore, the expression of the four miRNAs could, singly or jointly, alter the expression of the key components in the phosphoinositide 3-kinase (PI3K)/Akt pathway, including PIK3CA, PIK3CD, PIK3R1 and Akt, along with their downstream signal, cyclin D1. CONCLUSIONS: These results suggested that the four miRNAs could promote prostate cancer cell proliferation by co-regulating the expression of PTEN, PI3K/Akt pathway and cyclin D1 in vitro. These findings increase understanding of the molecular mechanisms of prostate carcinogenesis and progression, even provide valuable insights into the diagnosis, prognosis, and rational design of novel therapeutics for prostate cancer.

[Effect of ultrasonic cavitation on ICP source radiation intensity].

In order to increase the intensity of inductively coupled plasma radiation and reduce the detection limit of analysis, the experiment studied on the change of surface tension and viscosity of the water samples which were processed by the ultrasonic cavitation, meanwhile the influence of cavitation effect to samples' spectral intensity and signal-to-background ratio was researched. The experimental results showed that the surface tension and viscosity of sample solution initially decreased and then increased as the ultrasonic power and cavitation time monotonously increased, and the minimum value could be achieved at the ultrasonic power of 50W and the cavitation time of 15 minutes. Under the best experiment condition (the ultrasonic power of 50W and the cavitation time of 15 min), the results revealed that the spectral lines intensity of element Al, Cd) Mn, Ni, Pb and Zn were increased around 56.73%, 57.23%, 44.57%, 43.20%, 39.04% and 40.19% than that without cavitation treatment, spectral signal-background ratio increased about 61.54%, 64.86%, 40.95%, 52.27%, 37.84% and 40.84%, respectively. Thus it can be seen that cavitation-processed water solution can improve the quality of Inductively Coupled Plasma-atomic emission spectrum.

[Spectrum diagnostics for the time of pre-sputtering in thin films deposited by magnetron puttering].

Abstract A plasma analysis system comprised of Omni-X300 series grating spectrometer, CCD data acquisition system and optical fiber transmission system was utilized in the present paper to realize the real-time acquisition of plasma emission spectra during the process of radio frequency (RF) magnetron sputtering. The plasma emission spectra produced by NiTa, TiAl ceramic targets and NiA1, TiA1 alloy targets were monitored respectively, in addition, the behavior of analysis lines of Ta I 333.991 nm, Ni I 362.473 nm, Al I 396.153 nm and Ti I 398.176 nm with time was obtained, according to which the time of pre-sputtering of the four kinds of target materials was fixed. At the same time, for the TiAl alloy target as the research object, the influence of different powers and pressures on the time of pre-sputtering was studied.

Role and fate of SP100 protein in response to Rep-dependent nonviral integration system.

Previously, we studied an AAVS1 site-specific non-viral integration system with a Rep-donor plasmid and a plasmid containing adeno-associated virus integration element. Our earlier study focused on the plasmid vector itself, but the cellular response to the system was still unknown. SP100 is a member of the promyelocytic leukemia nuclear bodies. It is involved in many cellular processes such as transcriptional regulation and the cellular intrinsic immune response against viral infection. In this study, we revealed that SP100 inhibited the Rep-dependent nonviral integration. Conversely, transient expression of Rep78 increased the degradation of SP100. This degradation was inhibited by treatment with MG132, an inhibitor of the ubiquitin proteasome. SP100 and Rep78 are both located in the nucleolus, which provides the spatial possibility for their interaction. Rep78 was coimmunoprecipitated with the enhanced green fluorescent protein (EGFP)-SP100 fusion protein but not EGFP, which verified the interaction between Rep78 and SP100. These results have enriched our knowledge about the cellular protein SP100 and Rep-dependent nonviral integration. It may lead to an improvement in the application of Rep-related transgene integration method and in the selection of target cells.