Abstract: A multi-target nucleic acid detection kit for human papillomavirus (HPV) typing includes a recombinase polymerase amplification (RPA) primer set, an enzyme and a buffer system for Cas12a-crRNA, and a reporter molecule that displays a signal. In the detection method, a multi-channel microfluidic chip is used as a carrier, and RPA primers are designed for corresponding regions of different HPV subtypes to allow isothermal amplification. A crRNA set is designed for amplicons of different subtypes. The crRNA recognizes an HPV target in a sample, and then activates the CRISPR-Cas12a and cuts a reporter group to release a signal, thereby achieving accurate detection on HPV subtypes. The detection method shows a high sensitivity, a low cost, and easy operations, and is expected to be widely used in the screening of HPV infection.

Abstract: A method for separating oil-water two-phase NMR signals by using dynamic nuclear polarization comprising: using a combination of a non-selective free radical and a selective relaxation reagent to selectively enhance an NMR signal of an oil phase or a water phase, the relaxation reagent being capable of selectively suppressing dynamic polarization enhancement of the water phase or oil phase, thus achieving the polarization enhancement of a single fluid phase in the mixed fluid phases and realizing separation of the two-phase signals; or using a selective free radical to selectively enhance the NMR signal of the oil phase or the water phase, thus achieving the polarization enhancement of a single fluid phase in the mixed fluid phases and realizing separation of the oil-water two-phase NMR signals. The method is simple and easy to operate, has a short test time, and can efficiently separate NMR signals of oil and water phases.

Abstract: A method for measuring oil-water distribution using DNP-MRI, comprising adding a free radical for DNP enhanced NMR signal of a water phase or an oil phase in a sample containing oil and water; performing an MRI experiment on the sample, and collecting an MRI image of the sample without DNP enhancement; applying microwave excitation for DNP-MRI experiment under the same MRI experiment condition as step 2, and collecting an MRI image of the sample after DNP enhancement; and comparing the MRI image after DNP enhancement with the MRI image without DNP enhancement. In the MRI image with DNP enhancement, an area with enhanced MRI signal intensity is a selectively enhanced fluid phase distribution area, and an area without obviously changed MRI signal intensity is a non-selectively enhanced fluid phase distribution area. The method is simple, convenient to operate, short in measurement time, and high in measurement efficiency.