Abstract: The present invention provides a palladium precatalyst for cross-coupling reaction, the palladium precatalyst comprising a structure represented by following formula 1: wherein, R1 and R2 are the same, and R1 and R2 are substituted or unsubstituted phenyl; R3 and R4 are the same, and R3 and R4 are substituted or unsubstituted phenyl or cyclohexyl.

Abstract: A method, an apparatus and a system for cell detection are provided. In the apparatus, a hyperspectrum module is used to capture information across electromagnetic spectrums from an image, a stereo camera module is used to capture three-dimensional image information, and the hyperspectrum module and the stereo camera module form a trinocular micro spectrometer. A microscopic optical module is provided for the two modules to form hyperspectrum and three-dimensional image information from a cell and its split cells via a lens. In the method, a series of continuous images are obtained within a time period. An observation image array with a plurality of observation image zones are provided to retrieve coordinates of a plurality of feature points at different times. Finally, a holistic cellular activity can be obtained by analyzing continuous hyperspectrum and 3D image information from the images over time.

Abstract: An E. coli expression system for producing mature human tyrosinase is provided and includes an E. coli host, which has a trait for expressing endogenous methionyl aminopeptidase in cytoplasm, and an expression vector transformed into the E. coli host. The expression vector has a replication origin sequence of an E. coli, and the expression vector includes an inducible promoter and a DNA fragment of human tyrosinase having a sequence referenced as SEQ ID NO:3, wherein a 5? end of the DNA fragment is constructed at a restriction enzyme NdeI recognition site located at the downstream of the inducible promoter.