Abstract: A cordycepin-based derived compound with an anti-tumor effect, and a structure of the compound is as shown in formula I; a cordycepin derivative and a pharmaceutical composition thereof provided by the invention have a good anti-tumor proliferation effect; compared with a parent drug, the cordycepin derivative has better affinity to cell membranes, so that a half-life period of in-vivo metabolism of the drug is longer, and in-vivo remaining time of the drug is longer; compared with other nucleoside anti-tumor drugs, the cordycepin derivative and the pharmaceutical composition thereof provided by the invention have wider types and action ranges of tumors, have excellent inhibition effects on a gastric cancer, a pancreatic cancer, a liver cancer, a small cell lung cancer, a colorectal cancer, melanoma, an ovarian cancer and the like, and have lower side effects and better curative effects.

Abstract: A method for analyzing droplets based on images: obtaining a working dye channel image and a reference dye channel image corresponding to a droplet system (S1); separately performing a preset image processing operation on the working dye channel image and the reference dye channel image (S2); using the working dye channel image or the reference dye channel image as a target image (S3), and determining a region in which each droplet is located from within the target image (S4); and on the basis of the determined region in which each droplet is located, analyzing the droplet system (S5). The method can effective effectively improve the accuracy of droplet analysis. Further provided are a computer device and a storage medium.

Abstract: Provided is a PCR-free library construction and sequencing method. A PCR-free high-throughput sequencing method is provided, including the following steps: obtaining a DNA fragment of target size by performing or not performing, based on a size of a nucleic acid sample, fragmentation on the nucleic acid sample; performing end repair and an A-tailing reaction; ligating an adapter containing a barcode; obtaining DNA nanoballs by performing single-strand cyclization and rolling circle replication; and loading and sequencing.

Abstract: Provided are a hooked probe, a method for ligating a nucleic acid and a method for constructing a sequencing library. The hooked probe comprises a target specific area and a hooked area ligated thereto; the target specific area comprises a sequence complementarily paired with at least part of the single chain of the nucleic acid fragment to be ligated; the hooked area comprises a sequence unpaired with the nucleic acid fragment; the end of the hooked area is a ligatable end; and the ligatable end can ligate the end of the single chain of the nucleic acid fragment.

Abstract: Provided are a rolling circle amplification method, a method for preparing a sequencing library, and a DNA nanoball prepared therefrom. The rolling circle amplification method includes: sequentially denaturing and annealing a double-stranded DNA and a mediating sequence in a same system, to complementarily pair the mediating sequence with two ends of a denatured single-stranded DNA; simultaneously introducing a ligase and a polymerase into the system to connect the two ends of the single-stranded DNA under action of the ligase; and performing a rolling circle amplification reaction under action of the polymerase by using the mediating sequence as a primer and the single-stranded DNA as a template, to obtain DNA nanoball.

Abstract: A nanopore sequencing method, including: in a nanopore sequencing device, performing rolling circle amplification by using a single-strand ring or double-strand ring of nucleic acid as a template to produce an amplified single strand; under the action of an electric field, introducing the amplified single strand into nanopores of the nanopore sequencing device, so that the amplified single strand passes through the nanopores and generates an electrical signal for each base. By determining electrical signal differences caused by different bases, a base sequence on a template nucleic acid is measured.

Abstract: Provided are a hooked probe, a method for ligating a nucleic acid and a method for constructing a sequencing library. The hooked probe comprises a target specific area and a hooked area ligated thereto; the target specific area comprises a sequence complementarily paired with at least part of the single chain of the nucleic acid fragment to be ligated; the hooked area comprises a sequence unpaired with the nucleic acid fragment; the end of the hooked area is a ligatable end; and the ligatable end can ligate the end of the single chain of the nucleic acid fragment.