Abstract: The present disclosure relates to the field of bioengineering and pharmaceutical and chemical production. In particular, provided is a polynucleotide comprising a coding sequence of toluene dioxygenase. Also provided are an expression cassette, a vector and a host cell comprising the polynucleotide, as well as use thereof in the preparation of cis-cyclohexadiene o-diol compounds.

Abstract: The present invention provides a method for biological and chemical synthesis of tetrodotoxin, specifically comprising the following steps: using cheap and easily available benzyl acetate as a raw material, and performing biological fermentation to obtain an optically pure intermediate ((5S, 6R)-5, 6-dihydroxycyclohexa-1, 3-dienyl) methyl acetate (formula I); and performing a series of chemical conversions on the intermediate to finally obtain tetrodotoxin at a purity of 95% or more without purifying the product. The present invention has the potential of large-scale production, and is an excellent alternative to the existing extraction method from a pufferfish.

Abstract: The present application provides a negative pressure boosting net cover and an electric fan mosquito swatter. The negative pressure boosting net cover comprises a bracket and a negative pressure boosting assembly, wherein the bracket is connected to the negative pressure boosting assembly, and the negative pressure boosting assembly is fixed at the air inlet of the fan cover shell. The negative pressure boosting assembly is composed of at least one negative pressure boosting body, which are fixed at the air inlet of the fan cover shell through brackets. Gaps between the negative pressure boosting body and the negative pressure boosting body/fan cover shell forms the ventilation openings and air passages. The technical solution of the present application expands the mosquito trapping range, enhances the suction force, and improves the mosquito trapping efficiency; on the premise that the limited power of the fan is not increased.

Abstract: An automatic lifting and feeding device includes a main controller, a material thickness detecting device, a material loading mechanism for placing materials and driving the materials to rise and fall, a material taking mechanism for transferring materials and a height detecting mechanism for detecting the height of the materials, wherein, the material thickness detecting device, the material loading mechanism, the material taking mechanism and the height detecting mechanism are respectively connected to the main controller. The height detecting mechanism includes a bracket and the height testing part connected to the bracket, and the detector for detecting the material distance is arranged on the height testing part. The invention also provides an automatic lifting feeding method. The advantage of the invention is that the height does not need to be adjusted manually. The device can automatically detect the height of the material, and achieves high efficiency.

Abstract: An image search method is provided. In the method, an image selection page of a messaging application is displayed. An input image for a search is determined based on an operation performed by a user on the image selection page. A search is performed for at least one output image similar to the input image based on a plurality of types of image characteristics that indicate levels of similarity between images. Each of the ay least one output image is determined to be similar to the input image based on at least one of the types of image characteristics. A search result list is generated according to the at least one output image. Further, the search result list is displayed.

Abstract: An automatic lifting and feeding device includes a main controller, a material thickness detecting device, a material loading mechanism for placing materials and driving the materials to rise and fall, a material taking mechanism for transferring materials and a height detecting mechanism for detecting the height of the materials, wherein, the material thickness detecting device, the material loading mechanism, the material taking mechanism and the height detecting mechanism are respectively connected to the main controller. The height detecting mechanism includes a bracket and the height testing part connected to the bracket, and the detector for detecting the material distance is arranged on the height testing part. The invention also provides an automatic lifting feeding method. The advantage of the invention is that the height does not need to be adjusted manually. The device can automatically detect the height of the material, and achieves high efficiency.