Near-death experience is a unique consciousness, a self-related, mysterious and unexplainable experience, which occurs in life-threatening and non-life-threatening situations, and could be classified as"classical near-death experiences"and"near-death-like experiences (NDEs-like)", respectively. The classical near-death experience corresponds to the internal awareness experienced in unresponsive conditions, which can be used to explore the disconnected states of consciousness of human beings. Meanwhile, the near-death-like experience is a more heterogeneous state, which brings more possibilities for future research. This article reviews the research progress of near-death experiences in different situations, such as cardiac arrest, syncope and meditative state, etc. Researchers found that people with rapid eye movement invasion are more likely to have NDEs and ketamine-induced general anesthesia can be used as a reversible and safe experimental model. Although many physiological and psychological explanations of near-death experiences have been proposed, the definition of the phenomenon, the mechanisms by which it occurs and the identification of near-death experiences remain controversial. Research on near-death experiences in China is still in its infancy. As a field of consciousness research, near-death experiences can be used to explore the mechanism of human consciousness in an unresponsive state, and to provide a new direction for the scientific research of clinical consciousness.

Near-death experience is a unique consciousness, a self-related, mysterious and unexplainable experience, which occurs in life-threatening and non-life-threatening situations, and could be classified as"classical near-death experiences"and"near-death-like experiences (NDEs-like)", respectively. The classical near-death experience corresponds to the internal awareness experienced in unresponsive conditions, which can be used to explore the disconnected states of consciousness of human beings. Meanwhile, the near-death-like experience is a more heterogeneous state, which brings more possibilities for future research. This article reviews the research progress of near-death experiences in different situations, such as cardiac arrest, syncope and meditative state, etc. Researchers found that people with rapid eye movement invasion are more likely to have NDEs and ketamine-induced general anesthesia can be used as a reversible and safe experimental model. Although many physiological and psychological explanations of near-death experiences have been proposed, the definition of the phenomenon, the mechanisms by which it occurs and the identification of near-death experiences remain controversial. Research on near-death experiences in China is still in its infancy. As a field of consciousness research, near-death experiences can be used to explore the mechanism of human consciousness in an unresponsive state, and to provide a new direction for the scientific research of clinical consciousness.

Objective:To compare the differences in clinicopathological characteristics between papillary thyroid microcarcinoma (PTMC) and papillary thyroid carcinoma (PTC) with a diameter≥2 cm.Methods:Clinicopathological and follow-up information of 1 404 PTC cases with diameter≤9 cm who received surgery and were confirmed pathologically from January 2010 to May 2017 in the First Hospital of China Medical University were analyzed retrospectively. All cases were divided into PTMC group and diameter ≥2 cm PTC group according to tumor diameter. The diameter of ≥2 cm PTC group was further categorized into two subgroups with 4 cm as the boundary. Clinical and pathological characteristics were analyzed. Meanwhile, risk factors that affected lymph node metastasis and postoperative recurrence of tumor were analyzed as well.Results:(1) A total of 1 404 eligible patients were included, consisting of 1 001 cases (71.3%) of PTMC and 403 cases (28.7%) of PTC of diameter≥2 cm with a median follow-up time of 43.00 (8.00-94.00) months. There were statistical differences in gender, age, serum thyroid stimulating hormone (TSH) level, bilobe, multifocality, cervical lymph node metastasis, extrathyroidal extension, body mass index, postoperative death, postoperative recurrence, and 131I treatment rate between two groups. Age, serum TSH level, bilobe, multifocality, cervical lymph node metastasis, extrathyroidal extension, postoperative recurrence, and 131I treatment rate were found statistically different among the PTMC group, 2 cm≤diameter≤4 cm PTC group, and 4 cm