You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Successful production of piglets derived from expanded blastocysts vitrified using a micro volume air cooling method without direct exposure to liquid nitrogen . This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling ( MVAC ) method without direct contact with liquid nitrogen ( LN₂ ) . Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol , 0.6 M trehalose and 2 % ( wt/vol ) polyethylene glycol in 10 % HEPES-buffered PZM-5 . The blastocysts were collected from gilts and vitrified using the new device ( MVAC ) or a Cryotop ( CT ) . Blastocysts were stored in LN₂ for at least 1 month . After warming , cryoprotective agents were removed using a single step . Survival of the embryos was assessed by in vitro culture ( Experiment 1 ) and by embryo transfer to recipients ( Experiment 2 ) . In Experiment 1 , the embryos vitrified by the MVAC or CT and fresh embryos without vitrification ( Control ) were used . The survival rates of embryos in the MVAC , CT and Control groups were 88.9 % ( 32/36 ) , 91.7 % ( 33/36 ) and 100 % ( 34/34 ) , respectively , after 48 h culture , and the hatching rates of embryos after 48 h incubation were 69.4 % ( 25/36 ) , 63.9 % ( 23/36 ) and 94.1 % ( 32/34 ) , respectively . In Experiment 2 , 64 vitrified embryos were transferred to 5 recipient gilts , and 8 healthy piglets were produced from 3 recipients in the MVAC group . Similarly , 66 vitrified embryos were transferred to 5 recipient gilts , and 9 healthy piglets were produced from 2 recipients in the CT group . These results indicated that porcine expanded blastocysts can be cryopreserved using the MVAC method without potential pathogen contamination from LN₂ .
{"Intervention": ["micro volume air cooling method", "micro volume air cooling ( MVAC )"], "Outcome": ["hatching rates of embryos after 48 h incubation", "production"], "Participant": ["piglets"]}