Objective To understand the status and related influencing factors of critical thinking of medical students, so as to provide recommendations for the training methods of critical thinking of medical students. Methods A total of 380 medical students in third and fourth grade of a medical university were investigated by using the California Critical Thinking Tendency Questionnaire and stratified random sam-pling method. 356 valid questionnaires were recovered. SPSS 22.0 software was used for statistical analysis, including t-test, analysis of variance and multiple linear regression analysis and other methods. Results The Cronbach'sαcoefficient of the scale was 0.728, and the cumulative variance contribution rate was 68.43%. The average score of positive critical thinking ability of medical students was 196.02, showing that they had positive thinking ability. Multiple linear regression analysis showed that the degree of extracurricular read-ing, whether there was a part-time job, and the students' self-study time per week had positive correlation with the critical thinking of medical students (P<0.05). Conclusion The critical thinking ability of medical students needs to be improved and the factors of critical thinking need to be further studied, and the research and practice of cultivating medical students' critical thinking ability must be deepened.

3 months group,6 neonates were admitted to intensive care unit,2 with birth defects and 1 died. Conclusion There was no clear evidence in this study demonstrating any association between adverse perinatal outcomes and pregnancy immediately after spontaneous abortion.

BACKGROUND:Numerical stimulation technology is a good method to analyze blood flow changes after intracranial aneurysm stenting that oftenresult in restenosis.
OBJECTIVE:To explore the hemodynamic effect of stent implantation on patient-specific intracranial aneurysm and the distribution of the wal shear stress on the stent surface.
METHODS:Brain CT data from a patient with intracranial aneurysm were extracted and optimized to establish a patient-specific intracranial aneurysm materialization model. Meanwhile, a three-dimensional model of rectangular section spiral stent was designed to develop an aneurysm model with the stent by the method of boolean operation. Then, the possibility of restenosis was analyzed based on the distribution of wal shear stress on the surface of stent model.
RESULTS AND CONCLUSION:The wal shear stress on the stent surface which was more than 40 Pa increasedalong with the increase of blood velocity and blood viscosity at the same moment. However, the wal shear stress on the stent surface which was less than 0.5 Pa decreased along with the increase of blood viscosity, and its distribution was the largest when the blood velocity was 0. This stent provides a new insight into the controling of the aneurysm growth and rupture, but the restenosis area is too large. In order to prevent restenosis, the stent need to be optimized or reselected to keep the desired shear stress values of 0.5 to 40 Pa, and meanwhile to minimize the pulsating change of wal shear stress during a cardiac cycle.

Medical implant communication service (MICS) is a standardized short-range wireless communication with ultra low power consumption applied for medical implant devices,which has been widely used all over the world.It is necessary to establish a unified international MICS standard.This paper details ITU-R SA.1346 standard from four aspects of technical parameters,compatibility,anti-interference methods and reliability of data transmission,and introduces the applications of MICS standard in Europe and America.Furthermore,comparison and analysis of the technical criteria in the above areas is conducted.

Objective To estabolish the ALDH2 Glu504Lys genotyping technique for oral swab sample type based on PCR-gold magnetic nanoparticle chromatographyl.Methods According to the ALDH2 Glu504Lys gene the specific primers were designed by ARMS-PCR technique.Optimized the optimal ALDH2 Glu504Lys oral swab reaction system and PCR reaction procedures based on the routine reaction conditions and reaction procedure of laboratory PCR.60 samples of oral swabs were collected and tested by gold magnetic nano-chromatography.The results were verified by sequencing.Results The detected 60 cases of oral swab samples contain 16 cases heterozygous mutation,wild type 42 cases,homozygous mutation 2 cases and then the results by Goldmag nanoparticle detection was perfectly matched with sequencing results.Conclusion The Goldmag nanoparticles chromatographic detection technique of ALDH2 Glu504Lys buccal swabs system was established.With accuracy,fastness,reliability,it is worthy of clinical promotion.

Objective To explore transinfection of rabbit chondrocytes via chitosan microsphere with human IL-1Ra and TGF-β1 gene. Methods Chitosan-DNA microspheres carrying plasmids with IL-1 Ra and TGF-β1 genes were prepared.The encapsulation efficiency,DNA-released kinetics and lysozyme degradation in vitro were performed.Articular rabbit chondrocytes were co-transinfected with the plasmids with IL-1Ra and TGF-β1 genes via chitosan-DNA mierosphere,evaluated by fluorescence microscope,TaqMan real-time PCR assay and MTF test. Results The chitosan microspheres with IL-1Ra and TGF-β1 genes were(2.8±0.2)μm and(2.6±0.1)μm in diameters respectively.The encapsulation efficiency were(88.3±4.1)%and(87.2±2.6)%.During the degradation,significant morphological changes were noticed.The plasmids could be released in a multiphasic fashion.Enhanced green fluorescent protein and Real-Time PCR analysis showed that genes were expressed in chondrocytes.lasting near 30 days.MTT indicated that the cotransinfection promoted the chondrocytes'proliferation. Conclusion IL-1Ra and TGF-β1 genes cotransfected into chondrocytes via chitosan-DNA microsphere could be expressed in a long term and cotransinfection promoted the chondroeytes'proliferation,which is the base of inhibiting the degeneration of cartilage and promote cartilage repair.

AIM:To investigate the effects of seipin gene deficiency on renal injury and the possible mecha-nisms in seipin-/-mice.METHODS:Six-month-old male seipin knockout ( seipin-/-) and wild-type ( WT) mice ( n=8) were used to study 24 h urinary albumin excretion ( UAE) , renal functions, pathological changes, and plasma leptin and adiponectin levels.Seipin mRNA expression in different tissues and each part of the kidney was also measured in WT mice.RESULTS:Real-time PCR analysis showed seipin mRNA expression in WT mice was higher in adipose tissue and testicles, and was also found in the kidney, which was mainly in glomeruli.Compared with control group, seipin-/-group showed increased kidney weight/tibia length (P<0.01), 24 h UAE (P<0.01), creatinine clearance (P<0.01), and glomerular and mesangial surface area (P<0.05).Both plasma leptin (P<0.01) and adiponectin (P<0.05) levels were significantly decreased in seipin-/-mice.CONCLUSION:Seipin gene deficiency in mice leads to renal injury prob-ably by decreasing plasma leptin and adiponectin levels due to lack of adipose tissue.

Objective To explore the correlation between heart rate recovery after exercise test and disease severity in patients with chronic obstructive pulmonary disease(COPD)and assess its impact on the exercise capacity of COPD patients.Methods Arterial blood gas analysis, pulmonary lung function test and cardiopulmonary exercise testing were performed in 60 patients with stable COPD and 50 healthy volunteers.Based on the heart rate recovery after exercise test, COPD patients were divided into normal heart rate recovery group(n =41)and abnormal heart rate recovery group(n =19).Results The COPD patients had lower exercise capacity(peak oxygen uptake as percentage of predicted value, peak VO2％ pred)(66 ± 15vs.89±11, P＜0.01), peak heart rate [(134±21)vs.(149±13)beats/min, P＜0.01], heart rate recovery[(18 ± 9)vs.(27 ± 10)beats/min, P ＜ 0.01] and higher resting heart rate [(83 ± 13)vs.(77 ± 13)beats/min, P ＜0.01] than the controls.Compared with normal heart rate recovery group, forced expiratory volume in one second as percentage of predicted(FEV1 ％ pred)and exercise capacity decreased more significantly in abnormal heart rate recovery group(38 ± 15 vs.52 ± 16, P＜0.05 and 57 ± 12 vs.71 ±14, P ＜0.01).Heart rate recovery was significantly correlated with FEV1％ pred and peak V O2％ pred(r=0.42, P ＜ 0.01 and r =0.52, P ＜ 0.01).Multivariate regression analysis showed that heart rate recovery and FEV1 ％ pred could be used as independent predictors of exercise capacity in COPD patients.Conclusion In COPD patients, heart rate recovery is correlated with the degree of disease severity and it may be an independent predictor of exercise capacity.

Objective:To summarize the ultrasound characteristics of incarceration of gravid uterus (IGU) for improving the diagnostic accuracy of IGU.Methods:Three cases of IGU patients were diagnosed in Peking University Third Hospital from May 2018 to May 2020. CNKI, Wanfang Data, China Science and Technology Journal Database and PubMed were searched using the search terms "incarcerate uterus" or "uterine incarceration" and "gravid" through January 2000 to July 2020, 53 IGU cases were found. The ultrasound data and outcomes of the 56 IGU patients were retrospectively analyzed. The display rate of various ultrasonic features were counted. Relevant literatures were reviewed and the experience were summarized.Results:Of the 56 cases with IGU, 45 cases (80.4%) had positive results, of which 34 cases (60.7%) were found abnormal cervix(elongated anteriorly and superiorly displaced cervix or poorly visualized cervix), 27 cases (48.2%) were found retroversion of the gravid uterus, 12 cases (21.4%) were found that the fundus of the uterus lay deeply in the Douglas pouch, 4 cases (7.1%) were found anteriorly and superiorly displaced bladder. There was statistically significant difference between the displaying rates of abnormal cervix and retroversion of the gravid uterus(χ 2=5.452, P<0.05). Conclusions:Abnormal cervix was the most common feature of IGU by ultrasound. Correct identification of the cervix is helpful to improve the detection rate of IGU.