Abstract: An online system for determining advertisements for retrieval is disclosed. The online system may assign a unique category path associated with a hierarchy of advertisement categories to a plurality of advertisements accessible by the online system to determine advertisement information features. The online system may determine a plurality of types of user engagements associated with prior user interactions by a user with one or more of the advertisements or types of advertisements associated with the advertisements to determine a set of user engagement features. The online system may select user engagement features, from the set, based on determined user engagement results to obtain user related features. The online system may associate the user related features with an assigned unique category path, associated with the ad information features, to generate inverted index features. The online system may apply the inverted index features as inputs to a neural network.

Abstract: Provided herein is a nucleic acid extraction and the structure of a reaction chamber is improved such that a piston, a reaction chamber and a magnetic rod are independent of one another, magnetic beads are more concentrated, more sufficient adsorption, washing and elution are achieved, dead corners are eliminated, when the nucleic acid extraction and amplification device is used to perform nucleic acid extraction and amplification. The sensitivity and accuracy of nucleic acid detection can be further improved, and missing and wrong detection can be avoided.

Abstract: Provided herein is a nucleic acid extraction and the structure of a reaction chamber is improved such that a piston, a reaction chamber and a magnetic rod are independent of one another, magnetic beads are more concentrated, more sufficient adsorption, washing and elution are achieved, dead corners are eliminated, when the nucleic acid extraction and amplification device is used to perform nucleic acid extraction and amplification. The sensitivity and accuracy of nucleic acid detection can be further improved, and missing and wrong detection can be avoided.

Abstract: An online system for determining advertisements for retrieval is disclosed. The online system may assign a unique category path associated with a hierarchy of advertisement categories to a plurality of advertisements accessible by the online system to determine advertisement information features. The online system may determine a plurality of types of user engagements associated with prior user interactions by a user with one or more of the advertisements or types of advertisements associated with the advertisements to determine a set of user engagement features. The online system may select user engagement features, from the set, based on determined user engagement results to obtain user related features. The online system may associate the user related features with an assigned unique category path, associated with the ad information features, to generate inverted index features. The online system may apply the inverted index features as inputs to a neural network.