Spectral phase effects and control requirements of coherent beam combining for ultrashort ultrahigh intensity laser systems.

Based on the premise that further improvements to the size and damage threshold of large-aperture optical components are severely limited, coherent beam combining (CBC) is a promising way to scale up the available peak power of pulses for ultrashort ultrahigh intensity laser systems. Spectral phase effects are important issues and have a significant impact on the performance of CBC. In this work, we analyze systematically factors such as spectral dispersions and longitudinal chromatism, and get the general spectral phase control requirements of CBC for ultrashort ultrahigh intensity laser systems. It is demonstrated that different orders of dispersion influence intensity shape of the combined beam, and high-order dispersions affect the temporal contrast of the combined beam, while the number of the channels to be combined has little impact on the temporal Strehl ratio (SR) of the combined beam. In addition, longitudinal chromatism should be controlled effectively since it has a detrimental effect on the combined beam at the focal plane, both temporally and spatially.

[Effect of Telbivudine Tablet Combined Jianpi Bushen Recipe on HBV Specific Cytotoxic T Lymphocyte and HBeAg Seroconversion in Patients with HBeAg Positive Chronic Hepatitis B].

OBJECTIVE: To explore the effect of Telbivudine (LDT) Tablet combined with Jianpi Bushen Recipe (JBR) on serum hepatitis B virus (HBV) specific cytotoxic T lymphocyte (CTL) and HBeAg seroconversion in chronic hepatitis B (CHB) patients. METHODS: Totally 90 HBeAg-positive and human leukocyte antigen (HLA)-A2 positive CHB patients were randomly assigned to the treatment group and the control group, 45 cases in each group. Patients in the treatment group took LDT Tablet (600 mg, once per day) combined with JBR granule (twice per day), while those in the control group took LDT Tablet alone. The therapeutic course for all was one year. HBV DNA negative conversion rate, HBeAg seroconversion rate, and level of HBV specific CTL were compared after 1 year treatment; liver function, drug resistance mutations, and adverse reactions were also compared between the two groups. RESULTS: After 1 year treatment, HBV DNA negative conversion rate and HBeAg seroconversion rate were 88.89% (40/45) and 40.00% (18/45) in the treatment group, higher than those of the control group [68.89% (31/45) and 20.00% (9/45)], with statistical difference (P < 0.05). Level of HBV specific CTL in the treatment group was 0.78% +/- 0.09% after treatment, higher than that of the control group after 1 year treatment (0.54% +/- 0.11%) and that before treatment (0.36% +/- 0.07%), with statistical difference (P < 0.01). Level of HBV specific CTL in 27 patients with HBeAg seroconversion was 0.81% 0.10%, higher than that of 63 patients without HBeAg seroconversion (0.60% +/- 0.09%), with statistical difference (P < 0.01). ALT returned to normal in 44 cases of the treatment group (97.78%), while it was 42 cases (93.33%) of the control group, with no statistical difference between the two groups (P > 0.05). Total bilirubin (TBil) in the two groups all turned to normal. rtM204I variation occurred in 1 case (2.22%) of the treatment group and 2 cases (4.44%) in the control group. No obvious adverse reaction occurred in the two groups. CONCLUSION: LDT Tablet combined with JBR could elevate levels of HBV specific CTL and HBeAg seroconversion in CHB patients.

Hepatitis B surface antigen quantification at hepatitis B e antigen seroconversion predicts virological relapse after the cessation of entecavir treatment in hepatitis B e antigen-positive patients.

OBJECTIVES: To assess off-treatment virological relapse rates and to determine the role of hepatitis B surface antigen (HBsAg) quantification in predicting virological relapse after stopping entecavir (ETV) treatment in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB). METHODS: One hundred and twelve CHB patients for whom ETV was stopped in accordance with the Asian Pacific Association for the Study of the Liver guidelines stopping rules were enrolled. Patient HBsAg and HBV DNA levels were monitored every 4-12 weeks during ETV treatment and after ETV cessation. Post-treatment virological relapse was defined as a serum HBV DNA level of >10 000 copies/ml after stopping ETV treatment. RESULTS: The virological relapse rate at 52 weeks after stopping ETV was 48.2%. The post-treatment virological relapse rate was significantly higher in patients aged >50 years than in those aged <50 years (p < 0.001), and the virological relapse rate was significantly lower in patients with an HBsAg level <2.0 log10 IU /ml than in those with a level ≥ 2.0 log10 IU /ml at ETV cessation (p = 0.005). An HBsAg level of 2.5 log10 IU/ml at HBeAg seroconversion was the optimal cut-off value for predicting post-treatment virological relapse (p < 0.001). In those aged <50 years and with HBsAg ≤ 2.5 log10 IU/ml at HBeAg seroconversion, the relapse rate was only 5%. In patients with HBsAg ≤ 2.5 log10 IU/ml at HBeAg seroconversion, 52.4% achieved HBsAg levels ≤ 2.0 log10 IU/ml at ETV cessation, while in those with HBsAg >2.5 log10 IU/ml at HBeAg seroconversion, only 4.4% achieved this criterion. CONCLUSIONS: HBsAg levels can help guide the timing of cessation of ETV treatment. HBsAg levels of 2.5 log10 IU/ml at HBeAg seroconversion may be a useful marker to predict virological relapse after the cessation of ETV treatment in HBeAg-positive CHB patients.

Phase control requirements of high intensity laser beam combining.

Aiming at getting the general requirements of the beam combine for ignition scale laser facilities, the analytical expressions including the factors affecting the combine results are derived. The physical meanings of every part are illustrated. Based on these expressions, the effects of the factors, including the beam configuration, piston error, and tip/tilt error, are studied analytically and numerically. The results show that the beam configuration cannot affect the Strehl ratio (SR) of the combined beam, but it influences the FWHM of the main peak and the ratio of the main peak and the side peak. The beam separation should be no more than 1.24 times the individual beam width for the multibeam combine, and be close to the individual beam width for the two-beam combine as much as possible. The piston error can change the characteristics of the combine beam focus, including the peak intensity, the focal spot morphology, the fractional energy contained within a certain area, and the center of mass. For the two-beam combine, a piston error less than 2π/5 rad is suitable, and for the multibeam combine, the standard deviation of the piston error should be no more than 2π/10 rad. The tip/tilt error has a great influence on the combined results. It affects the superposition degree of the focal spots of the combined elements directly. A requirement of 0.5~1 µrad for the standard deviation of the tip/tilt error is adequate.