Abstract: The present disclosure provides an N protein epitope mutation marker for preparing an epitope deletion-marked vaccine strain of type II porcine reproductive and respiratory syndrome virus (PRRSV) and use thereof, belonging to the technical field of biological products. In the mutation marker, one or more amino acids are mutated based on an epitope sequence at positions 92 to 103 of a C-terminal of an N protein of the type II PRRSV; and the epitope mutation marker has an amino acid sequence shown in SEQ ID NO: 1, where X1 is selected from the group consisting of T, P, and A; and X2 is selected from the group consisting of V and A.

Abstract: The present invention discloses a non-hysteretic oxygen supply respirator system, comprising a respiratory mask, an inhaling pipe, an exhaling pipe, an oxygen supply chamber, an auxiliary oxygen supply pipeline, and a start-stop cylinder for opening and closing the auxiliary oxygen supply pipeline. The non-hysteretic oxygen supply respirator system in the present invention supplies a small amount of oxygen during the second half of exhaling by providing the auxiliary oxygen supply pipeline, so as to compensate for the amount of oxygen required by a user during the hysteretic time after the respirator senses the inhaling airflow, avoid the situation that the user inhales laboriously due to the hysteresis of inhaling oxygen supply, and give the user a better respiratory experience. The start and stop of the auxiliary oxygen supply pipeline are controlled by the airflow of the exhaling pipe, making the control simple and convenient and the exhaling smoother.

Abstract: A flexible patch for respiratory sound monitoring, comprising an acceptance box, an acceptance motor, an operation screen, a storage box, the flexible patch, a framework, a hand lever, a top cover, a detection range telescopic rod. The present disclosure provides the acceptance box, the storage box, the acceptance motor and an acceptance shaft to realize the purpose of convenient storage and access of flexible patches to prevent damage. And the flexible patch improves the measurement accuracy, the detection range telescopic rod that is connected with the upper part of the respiratory sound receiving sensor control the sensor slides along the slide rail to facilitate the adjustment of a sensor's monitoring range, and the respiratory sound horn amplifier set the lower part of the respiratory sound receiving sensor improves the detection effect of the sensor.