Freeform reflector light source used for space traceable spectral radiance calibration on the solar reflected band.

For purpose of improving the accuracy of in-orbit radiometric calibration of Chinese Space-based Radiometric Benchmark (CSRB) reference payload on the reflected solar band and reduce resource consumption, this paper proposed a freeform reflector radiometric calibration light source system based on the beam shaping characteristics of the freeform surface. The design method of initial structure discretization based on Chebyshev points was used to design and solve the freeform surface, and the feasibility of the design method was verified by optical simulation. The designed freeform surface is machined and tested, and the test results show that the surface roughness root mean square (RMS) of the freeform reflector is 0.61 µm, which indicates that the continuity of the machined surface is good. The optical characteristics of the calibration light source system are measured, the results show that the irradiance uniformity and radiance uniformity are better than 98% in the effective illumination area of 100 mm × 100 mm on the target plane. The constructed freeform reflector calibration light source system can meet the requirements of large area, high uniformity and light weight for onboard calibration of the payload of the radiometric benchmark, improving the measurement accuracy of spectral radiance on the reflected solar band.

Freeform reflector design for uniform illumination in a space-based remote sensor calibration system.

A freeform reflector for illumination in a space-based remote sensor calibration system is designed to produce the desired patterns and improve efficiency. Owing to the excellent cosine properties and light source stability of the integrating sphere, it is widely used as the calibration source in optical remote sensing instruments. However, the light source cannot obtain uniform illumination on a large scale. Therefore, we propose a freeform reflector design for an integral sphere source, which generates an independent irradiance distribution and achieves large-scale illumination by arraying. The irradiance uniformity and efficiency obtained were greater than 98% and 90%, respectively.

UBE3A alleviates isoproterenol-induced cardiac hypertrophy through the inhibition of the TLR4/MMP-9 signaling pathway.

Cardiac hypertrophy is considered to be a leading factor in heart function-related deaths. In this study, we explored the potential mechanism underlying cardiac hypertrophy induced by isoproterenol. Our results showed that isoproterenol induced cardiac hypertrophy in AC16 cells, as reflected by the increased cell surface area and increased hypertrophic markers, which was accompanied by increased ubiquitin-protein ligase E3a (UBE3A) expression. Moreover, UBE3A knockdown by siRNAs accelerated cardiac hypertrophy, suggesting that increased UBE3A expression induced by isoproterenol might be a protective response and UBE3A might be a protective factor against cardiac hypertrophy. Our study also revealed that UBE3A knockdown increased the protein expression of the TLR4/MMP-9 pathway that has been shown to be associated with cardiac hypertrophy, which suggested that UBE3A-mediated protection is likely to be associated with the blockade of the TLR4/MMP-9 signaling pathway. UBE3A might be thus a potential target gene for the treatment of cardiac hypertrophy.

Optical design of double-grating and double wave band spectrometers using a common CCD.

A new type of optical system comprising double-grating and double wave band spectrometers is designed for atmospheric detection. The optical system can bring oxygen A band (758-778 nm) and water vapor absorption band (758-880 nm) on a charge-coupled device (CCD) at the same time for ultrahigh resolution spectrum measurement. Each absorbed band with three observation directions of atmospheric radiation is imaged in different positions of a common CCD. The spectral resolution is less than 0.07 nm in oxygen A band (758-778 nm), and the spectral resolution is less than 0.28 nm in water vapor absorption band (758-880 nm). Three end faces of the optical fiber are on the slit plane for each wave band, and each end face corresponds to an observation angle. The optical fiber core diameter is 600 µm, the slit width is 25 µm, and the slit length is 18.4 mm. The principle of smile correction is analyzed. The smile of the Czerny-Turner double-grating spectrometer can be compensated by using the tilt field lens in front of the focal plane. The design results corroborate that the maximum smile of the double-grating spectrometer is 5 µm and that the approach of correcting smile is effective. The stray light is analyzed, and the approaches of suppressing the stray light are proposed.