Abstract: Provided is gRNA specifically targeting ?4GalNT2 gene. The gRNA specifically binds to the nucleotide sequence shown in any one of SEQ ID NOs. 1 and 2. Also provided are an animal model constructed using the gRNA, and an application thereof in the field of biomedicine.

Abstract: Provided is an SgRNA combination, comprising an SgRNA specifically targeting the GGTA1 gene, an SgRNA specifically targeting the CMAH gene and an SgRNA specifically targeting the ?4GalNT2 gene. Also provided is a CRISPR/Cas9 vector combination, comprising a GGTA1-CRISPR/Cas9 vector, a CMAH-CRISPR/Cas9 vector and a ?4GalNT2-CRISPR/Cas9 vector. Also provided is an applicaton of the CRISPR/Cas9 vector combination in knocking out the GGTA1 gene, the CMAH gene and the ?4GalNT2 gene. The knockout rates of the three genes with the specifically targeted SgRNA sequences are respectively 56%, 63%, and 41%. A three genes knockoutpig can be obtained, wherein the three genes related to immune rejectionare knocked out, and heart valves of said pig can be acquired.

Abstract: A blood product may be derived from a gene knockout pig and used in, e.g., medical applications. The binding of the blood product to immunoglobulin in human serum is reduced, and the blood product can have an effect on overcoming hyperacute immune rejection. The blood product may be derived from a gene knockout pig, wherein a GGTA1 gene, a CMAH gene, and/or a ?4GalNT2 gene of the gene knockout pig are knocked out, wherein one or more nucleotides in the ?4GalNT2 gene encoding one or more amino acids in exon 8 are deleted such that the ?4GalNT2 gene is knocked out.

Abstract: A method and system for determining contact angles of porous media, including: in a displacement simulation experiment, injecting a displacement fluid into a actual core sample, and performing computed tomography scanning on the core to determine three-dimensional images at different oil displacing time points; segmenting different phases of the three-dimensional images to obtain segmented three-dimensional images; marking a contact line between different phases according to the segmented three-dimensional images, where the phases are underground fluids or displacement fluids and a rock matrix in the displacement simulation experiment; and determining a contact angle of the porous media at different 3D positions at different time points according to the contact line. The method and system provided can obtain the dynamic changing process of the contact angle at different 3D positions in the core at different displacement time points, reflect the wettability of the real reservoir environment more accurately.

Abstract: Provided is an SgRNA combination, comprising an SgRNA specifically targeting the GGTA1 gene, an SgRNA specifically targeting the CMAH gene and an SgRNA specifically targeting the ?4GalNT2 gene. Also provided is a CRISPR/Cas9 vector combination, comprising a GGTA1-CRISPR/Cas9 vector, a CMAH-CRISPR/Cas9 vector and a ?4GalNT2-CRISPR/Cas9 vector. Also provided is an applicaton of the CRISPR/Cas9 vector combination in knocking out the GGTA1 gene, the CMAH gene and the ?4GalNT2 gene. The knockout rates of the three genes with the specifically targeted SgRNA sequences are respectively 56%, 63%, and 41%. A three genes knockoutpig can be obtained, wherein the three genes related to immune rejectionare knocked out, and heart valves of said pig can be acquired.

Abstract: The present invention discloses a method and system for determining contact angles of porous media. The method includes: in a displacement simulation experiment, injecting a displacement fluid into a real core, and performing computed tomography (CT) scanning on the core to determine three-dimensional images at different oil displacing moments; segmenting different phases of the three-dimensional images to obtain segmented three-dimensional images; marking a contact line between different phases according to the segmented three-dimensional images, where the phases are underground fluids or displacement fluids and a rock matrix in the displacement simulation experiment; and determining a contact angle of a porous medium at different positions at different moments according to the contact line.

Abstract: Disclosed is a compatible and magnetic absorption-type electronic building block, which comprises a circuit board, a plug connector and a socket connector, wherein the plug connector and the socket connector both comprise an insulation body and a conductive terminal, and the insulation body is arranged with a mounting body and two support feet. A bottom of the mounting body is arranged with an open region, and the mounting body is provided with a butting panel, a top panel and a rear cover. The electronic building block of the invention can not only implement electronic circuit module splicing, but also implement a complex three-dimensional modeling function due to the above specially designed structure. Moreover, the electronic building block can be seamlessly spliced to a common plastic building block in a market.

Abstract: Provided are genetic material and nucleic acid sequences useful in increasing yield, biomass, growth rate, vigor, nitrogen use efficiency and/or abiotic stress tolerance, preferably tolerance to nutrient deficiency of a plant. Specifically, the improvement of nitrogen fixation properties in cultivated plants is described.