[Characteristics of Key Size Spectrum of PM2.5 Affecting Winter Haze Pollution in Taiyuan].

PM2.5 is generally considered as a main pollutant causing the formation of haze. Based on meteorological parameters, aerosol distribution, and PM monitoring data in Taiyuan during November and December 2016, the characteristics of the key size spectrum of PM2.5 affecting haze were discussed. During the observation period, haze was frequent and serious. Heavy haze time accounts for 25.35% of the total haze time. Haze events occurred frequently when the relative humidity was greater than 80% and wind speed was less than 1.5 m·s-1, especially for severe haze. Mild and moderate level haze occurred frequently when the relative humidity was less than 80% and greater than 40% and when wind speed was less than 1.5 m·s-1. Slight haze mainly occurred when the relative humidity was 20%-40% and the wind speed was 1.25-2.55 m·s-1. The average mass concentration of PM2.5 was 209.45 µg·m-3, which was three times the level during non-haze events. With an increase in the haze level, the mass concentration of PM2.5 and the ratio of PM2.5/PM10 increased. PM1 was the key particle size affecting haze in the low humidity environment. PM0.5 was the key particle size that affects slight haze, mild haze, and moderate haze in the high humidity environment, while PM1 was the key particle size that affects heavy haze. The contribution of surface concentration to visibility decreased with high humidity, but the particle size increased by moisture absorption leading to an increase in the extinction efficiency factor, which compensated for the lack of surface concentration. The increase in the particle size parameter was an important factor for PM2.5 affecting the haze pollution with high humidity.

Rugate filters used in slit-lamp delivery to improve color rendering of illumination for retinal photocoagulation.

Laser filters and color filters used in slit-lamp delivery have been developed by the rugate approach to improve color rendering of illumination for retinal photocoagulation. The double-notch laser filter is designed according to the required laser lines and incident angle. Based on the transmission spectrum of a double-notch laser filter and the spectral power distribution (SPD) of the light source of a slit lamp, a scanning search algorithm is applied to find the optimal transmission spectrum of a multi-notch color filter for the best color rendering index of illumination. Open-source software is used to design the refractive index profile of the rugate filters, which are deposited by the reactive pulse magnetron sputtering. Both the theoretical analysis of SPD of slitlamp delivery with consideration of the deposited rugate filters and the experimental results demonstrate that the color rendering property of illumination can be improved remarkably, thus making fundus observation and retinal laser photocoagulation more reliable and efficient.

Numerical investigation of one-dimensional nonpolarizing guided-mode resonance gratings with conformal dielectric films.

We present the nonpolarizing resonance properties of two types of one-dimensional (1D) guided-mode resonance (GMR) gratings consisting of the sinusoidal-profile grating substrate and the conformal dielectric thin films. The optimization with respect to the grating height and the phase of the conformal graded-index layer is important for the design of nonpolarizing type-I GMR gratings. The thin films design of the conformal step-index multilayer and the optimization with respect to the grating height are of two critical steps to obtain the nonpolarizing type-II GMR gratings. Both of the two types of nonpolarizing GMR gratings can be designed to support single-mode resonance and multimode resonance under normal incidence.

Graded wavelike two-dimensional photonic crystal made of thin films.

A filling-factor-graded wavelike two-dimensional photonic crystal (2DPC) possessing a light-path bending effect that is polarization dependent is theoretically studied by using a qualitative analysis of the isofrequency curves. The numerical simulation results obtained by using the finite-difference time-domain method demonstrate that such a graded 2DPC has potential applications in a polarization splitter and a parallel-plane resonant cavity. A new kind of waveguide structure that combines a filling-factor-graded wavelike 2DPC and one-dimensional multilayer thin films is also discussed.

[Analysis on the genetic characteristics of the wide-type measles virus circulating in Zhejiang province in 2005].

OBJECTIVE: To study the genetic characteristics of measles viruses circulating in Zhejiang province in 2005. METHODS: 4 groups of measles viruses isolated in outbreaks and the H and N gene were amplified by reverse transcription polymerase chain reaction (RT-PCR). PCR products were purified, sequenced and data was analyzed. RESULTS: All of the 4 measles isolates belonged to genotype H1 which had been a main genotype containing all of the isolates in China. The isolates shared 99.2% -99.7% identity of amino acid sequence on H and 99.8% identity of amino acid sequence on N gene. When comparing to the China vaccine strain (Shanghai 191), there were 95.2%-95.5% homogeneties and 95.5% homogeneties on H and N gene respectively. CONCLUSION: Data from phylogenic trees of H and N gene revealed that the wide-type measles viruses circulating in Zhejiang province in 2005 all belonged to genotype H1. There were obvious differences on genetic characteristics between the isolates and the genotype A (Shanghai 191).

Indomethacin, dexamethasone, and intestinal damage in infant rats.

BACKGROUND: Indomethacin is commonly used in the Neonatal Intensive Care Unit to induce closure of the patent ductus arteriosus and to prevent intraventricular hemorrhage. It is known that indomethacin causes intestinal ulceration in adults, but its effect in infants is less clear. In a preliminary experiment, it was found that the administration of 10 mg/kg/d of indomethacin, a dose that damages the adult rat intestine, had no detrimental effects on newborn suckling rats whereas dexamethasone at 0.25 mg/kg/d caused significant growth failure and villous blunting. It was then hypothesized that the lack of intestinal damage with indomethacin in infants was related to protection given by mother's milk. METHODS: Subsequent experiments were performed wherein 10 mg/kg/d of indomethacin was provided to infant mother-reared, infant artificially fed, and adult rats. The expression of intestinal cyclooxygenases in the prostaglandin synthetic pathway of control rats was examined to initiate an exploration into a mechanism for the developmental response to indomethacin. RESULTS: Mother-reared and artificially fed infant rats demonstrated resistance to the ulcerogenic effects of indomethacin, in contrast to the adults. A differential presence of cyclooxygenase-1 and cyclooxygenase-2 was not distinctly seen between infancy and adulthood. CONCLUSIONS: The results indicate that a varying response to the damaging effects of indomethacin on the intestine occurs during development with the infant being less susceptible than the adult. This differed from the effects of dexamethasone administration, which caused significant intestinal atrophy in the infant rats. The intestinal protection to the effects of indomethacin in infants is not dependent on mother's milk or a developmental difference in the prostaglandin biosynthetic pathway.