Objective:To evaluate the influence of examination as a transient stressful life event on the psychological status and occlusal function of college students.Methods:47 student volunteers(17 males,30 females;aged 19.30 ± 1.53 years) with normal occlusion were enrolled.SCL-90 questionnaire for evaluation of psychological status and surface electromyography for assessment of masseter and temporalis activities in maximum voluntary teeth clenching and in chewing different foods were performed at two stages (stage 1:one week before final academic examination;stage 2:one week after spring festival holiday).Results:Scores of questionnaire evaluation of psychological status showed obvious change in factors of somatization,interpersonal sensitivity,depression,anxiety and paranoid ideation(P ＜0.05).Paired t-test analysis of masticatory muscle function showed changes only in percentage overlapping coefficient(POC) of masseters in chewing carrot and activity index(AC) in chewing preserved haw jelly(P =0.014 and 0.018 respectively).However,other chewing status and indexes were not significantly changed.Conclusion:The psychological status of college students can be significantly impacted by examination stress without influence on masticatory activities.

Objective　To evaluate the diagnostic value of MR I、CT、DSA for cerebral arteriovenous malformation(AVM). Methods　A total of 40 case of AVM were examined with imaging methods in which 19 MRI, 30 CT and, 12 DSA. Combination of two or three kinds of eximinations were perfo rmed in 20 and 4, respectively. Results　Diagnostic accordance r ate rate of CT was 70%, sensitivity and specificity of MRI were 100% and 84% res pectiv ely, diagnostic accordance rate of DSA was 92%. Conclusion　MRI,CT,D SA can play important roles in the diagnosis of AVM. MR and DSA are superior to CT. DSA could reveal the circulation time and the stealing blood situation of AV M and thus suggests the applicability of interventional embolization therapy.

BACKGROUND:Under co-culture conditions, mesenchymal stem cel s could regulate osteogenic differentiation and osteogenesis of osteoblasts. OBJECTIVE:To observe the osteogenic efficiency of osteoblastic precursor cel s co-cultured with undifferentiated bone marrow-derived mesenchymal stem cel s, umbilical cord-derived mesenchymal stem cel s, or placenta-derived mesenchymal stem cel s in mineralization medium. METHODS:Adipose-derived stem cel s were induced in osteogenic differentiation medium for 7 days before being indirectly co-cultured with undifferentiated mesenchymal stem cel s isolated from different tissues (bone marrow group, umbilical cord group and placenta group) in Transwel plates. Induced adipose-derived stem cel s cultured alone served as control group. At different experimental intervals, quantitative analysis of alkaline phosphatase activity and calcified matrix was preformed to observe the effects of mesenchymal stem cel s from different sources on the osteogenic efficiency of induced adipose-derived stem cel s. RESULTS AND CONCLUSION:Expression of alkaline phosphatase was significantly higher in different experimental groups than the control group (P<0.05), and it was also higher in the bone marrow group than the umbilical cord and placenta groups (P<0.05). Quantitative analysis of calcified matrix revealed that the experimental groups were significantly higher than the control group (P<0.05);and in experimental groups, the umbilical cord group was higher than bone marrow group and placenta group (P<0.05). These findings indicate that the osteogenic efficiency of induced adipose-derived stem cel s is improved dramatical y under co-culture conditions.

Objective To assess the value and feasibility of 64-slice spiral CT in diagnosis of coronary artery aneurysm in the follow-up of young children with previous Kawasaki disease. Methods Twelve boys (mean age 5.1 years) for follow-up (ranged 1.1 to 5.1 years) with known Kawasaki disease and coronary artery aneurysms underwent coronary CT angiography using 64-slice spiral CT.The number,location,shape and size of each coronary artery aneurysm were recorded and compared with those of echocardiography performed simutaneously. Results A total of 30 coronary artery aneurysms were identified with mean diameter of(7.5±3.8) mm,and mean maximum length of (12.4±9.1) mm.10 aneurysms were small in size,7 aneurysms were medium in size and 13 were giant aneurysms.Fourteen aneurysms were saccular,and the remaining 16 were fusiform. Among the aneurysms in left coronary artery,7 of them were located in the main branch,9 were located in the proximal segment of the anterior descending branch,4 were located at the middle segment of the anterior descending branch,and 2 were located in the circumflex branch.Among the aneurysms in right coronary artery,6 of them were located in the proximal segment,9 were located in the middle segment,and 4 were located at the distal segment.Nine of the aneurysms involved 2 segments of the coronary arteries,and one involved 3 segments.Six stenotic segments were found. Calcification was found in 5 aneurysms and 3 of them had thrombosis. Echocardiography failed to detect 8 aneurysms of small size and located in the middle or distal segments of the coronary arterys.Conclusion The 64-slice CT angiography proved valuable for monitoring young children with Kawasakidisease.

Objective: To explore the association between co-consumption of takeaway fast foods and sodas with depressive symptoms among Chinese adolescents, and to provide a reference for reducing the occurence of depression among adolescents. Methods: A multi-center population-based survey was conducted in 32 schools in 4 provinces across China. A total of 14 500 adolescents completed eligible questionnaires. Depressive symptoms were assessed by using Children’s Depression Inventory(CDI), while consumption of takeaway fast foods and sodas was collected using the semi-quantitative Food Frequency Questionnaire(FFQ). Results: 27.26%(3 952/14 500) of adolescents were reported of depressive symptoms. The low, middle, and high-frequency consumption of takeaway fast foods (a OR=1.12, 1.73, 1.56, P<0.05) and sodas (a OR=1.64, 2.17, 3.54, P<0.01) were associated with depressive symptoms, and dose-response relationships were observed in all association(P<0.01). Meanwhile, positive additive interactions were observed in the association(a OR=2.46, P<0.01). The relative excess risk, attribution ratio and the interaction index of synergy was 0.45(0.12-0.77), 0.18(0.06-0.30) and 1.44(1.10-1.89), respectively. Conclusion Co-consumption of takeaway fast foods and sodas significantly associates with depressive symptoms by synergistic effect among Chinese adolescents.

Objective: To simplify the psychological domain of Multidimensional Sub-health Questionnaire of Adolescents (MSQA),which includes 39 items and develop the Brief Instrument On Psychological Health of Youths(BIOPHY), as well as to evaluate the predictive validity of the BIOPHY. Methods: A total of 14 221 students were recruited from Shenyang,Xinxiang,Guangzhou,and Chongqing by using multistage stratified cluster random sampling to participate in the study. A combination of item analysis,factor analysis and reliability evaluation were used to screen items and evaluate the questionnaire. Meantime, data from 14 500 adolescents from Shenzhen,Nanchang,Zhengzhou and Guiyang in 2017 were used to develop a cut-off point and to evaluate its predictive validity. Results: On the basis of item analysis,BIOPHY consisted of 15 items. Variance cumulative contribution rate was 57.39%; internal consistency test showed that the total questionnaire Cronbach α coefficient was 0.928. The split-half coefficient of the total questionnaire was 0.909. The 90th percentile of total scores was used as the cutoff point of BIOPHY. The results of multivariate logistic regression analysis showed that students with psychological health symptoms were at significantly higher risk of depressive symptoms (OR=10.53,95%CI=9.28-11.94),suicide ideations (OR=5.77,95%CI=5.15-6.46),suicide plans (OR=6.09,95%CI=5.39-6.89) and suicide attempts (OR=4.80,95%CI=4.04-5.69) than normal counterparts. Conclusion The BIOPHY is consistent with the evaluation standard of psychometrics. The predictive validity of BIOPHY is good and could be used in the future researches focusing on adolescent mental health.

Objective:To develop a novel, flexible, dual-arm, master-slave digestive endoscopic minimally invasive surgical robot system named dual-arm robotic endoscopic assistant for minimally invasive surgery (DREAMS) and to evaluate its feasibility for endoscopic submucosal dissection (ESD) by using ex vivo porcine stomachs.Methods:A novel endoscopic robot (DREAMS) system was developed which was composed of a flexible two-channel endoscope, two flexible robotic manipulators, a master controller, a robotic arm, and a control system. A total of 10 artificial round-like lesions with diameters ranging from 15 to 25 mm were created (5 in gastric antrum and 5 in gastric body) by using fresh peeled stomach of healthy pigs as the model. Submucosal dissection was performed with the assistance of the DREAMS system by two operators. The main outcome was submucosal dissection speed, and the secondary outcomes included muscular injury rate, perforation rate, and grasping efficiency of the robot.Results:All 10 lesions were successfully dissected en bloc by using the DREAMS system. The diameter of the artificial lesions was 22.34±2.39 mm, dissection time was 15.00±8.90 min, submucosal dissection speed was 141.79±79.12 mm 2/min, and the number of tractions required by each ESD was 4.2 times. Muscular injury occurred in 4/10 cases of ESD. No perforation occurred. Conclusion:The initial animal experiment shows the DREAMS system is safe and effective.

Cross-modality reconstruction of medical images refers to predicting the image from one modality to another so as to achieve more accurate personalized medicine. Generative adversarial networks is the most commonly used deep learning technique in cross-modality reconstruction. It can generate realistic images by learning features from implicit distributions that follow the distributions of real data and then reconstruct the image of another modality rapidly. With the sharp increase in clinical demand for multi-modality medical image, this technology has been widely used in the task of cross modal reconstruction between different medical image modalities, such as magnetic resonance imaging, computed tomography and positron emission computed tomography. It can achieve accurate and efficient cross-modality image reconstruction in different parts of the body, such as the brain, heart, etc. In addition, although GAN has achieved some success in cross-modality reconstruction, its stability, generalization ability, and accuracy still need further research and improvement.
Brain/diagnostic imaging* ; Image Processing, Computer-Assisted/methods* ; Magnetic Resonance Imaging/methods* ; Positron-Emission Tomography ; Tomography, X-Ray Computed

Objective:To examine whether sleep status and social jet lag are related to the mental health behaviors in children and adolescents, providing a reference for preventing and improving children and adolescents' mental health behaviors.Methods:A large cross-section was conducted in Baoan District, Shenzhen, from April to May 2019. A total of 30 188 adolescents and children in grades 1-12 in 14 schools were included. The growth trajectory and health index questionnaire of primary and secondary school students were designed to evaluate the sleep status. Mental health behavior problems among students were accessed using the parents' and students' versions of the Strengths and Difficulties Questionnaire. After controlling for confounding factors of demographic variables, including gender, age, parental education level, academic performance, learning burden, and noise impact, a multivariate logistic regression model was used for statistical analyses.Results:The sleep duration of four grades students were 90.4％,90.1％, 98.2％, and 98.4％, respectively. 19.9％ did not have a post-lunch nap. 19.6％ had a wake-up delay of more than or equal to 2 h weekend morning. 35.1％ had an inconsistent bedtime and 15.5％ had an inconsistent awakening time. The multivariate logistic regression model showed that compared with 8-9 h, the sleep duration of elementary school juniors at night less than or equal to 7 h, 7-8 h increased the risk of psychological behavior problems. The sleep time more than 9 h was negatively correlated with psychological behavior problems. The sleep duration of elementary school seniors less than or equal to 7 h increased the risk of psychological behavior problems. The sleep duration of middle school and high school students less than or equal to 6 h increased psychological behavior problems. The ORs (95％ CI) appeared as 2.53(1.85-3.47), 2.41(1.11-5.25), respectively. The ones with a sleep time more than 9 h also increased the risk, and ORs (95％ CI) appeared as 2.37(1.40-4.01), 5.38 (1.79-16.1), respectively. Both the absence of post-lunch nap and the nap time less than 0.5 h were risk factors for psychological behavior problems in primary and middle school students. The nap time over 1-2 h was also a risk factor for high school students' psychological behavior problems. Waking up at irregular times in the morning, going to bed at varying times in the evening, and delaying getting up for more than or equal to 2 h on weekends were all risk factors for psychological and behavioral problems among primary and middle school students. The ORs (95％ CI) of psychological behavior problems of elementary school juniors and seniors, middle school and high school students were 2.07 (1.45-2.97), 1.57 (1.09-2.26), 2.66 (2.06-3.44), 2.48 (1.96-3.15), respectively. Conclusions:Sleep duration, no post-lunch sleep, and daily intraindividual variability of sleep is positively associated with poor mental health. Additionally, social jet lag is associated with mental health problems in students. It is noted that delaying sleep within half an hour on the weekends of elementary school juniors is significantly associated with an increase in bad mental behavior.

Objective:To analyze the relationship between migration time and the prevalence of myopia of children and adolescents aged between 6 and 18 years old in Shenzhen.Methods:From April to May 2019, 26 618 children and adolescents from 14 schools in six streets of Baoan District, including Fuyong, Shajing, Xin′an, Xixiang, Songgang and Shiyan, were included in the study by using random cluster sampling method. The demographic characteristics, migration status, self-reported myopia, screen time in the last seven days, outdoor activities in the last one month and other information were collected through the questionnaire. The differences of myopia among children and adolescents with different characteristics were compared by χ 2 test, and the relationship between migration time and the prevalence of myopia was analyzed by multivariate unconditional logistic regression model. Results:The age of 26 618 study participants was (12.37±3.49) years old, and the overall prevalence of myopia was 49.4%. Multivariate logistic regression analysis showed that after controlling for relevant confounding factors, compared with migrant children and adolescents of migrant workers who migrated for 1-2 years, those of migrant workers who had migrated for more than 6 years had a higher risk of myopia [ OR (95% CI): 1.48 (1.14-1.92)]. After being grouped by phase of school, in the lower grade group of primary school, the children and adolescents of migrant workers who had migrated for more than 6 years had a higher risk of myopia compared with those of migrant workers who migrated for 1-2 years [ OR (95% CI): 1.96 (1.20-2.74)]. In the high school group, compared with the children and adolescents of migrant workers who migrated for 1-2 years, those of migrant workers who had migrated for 3-5 years and ≥6 years had a higher risk of myopia [ OR (95% CI): 6.03 (1.29-28.15) and 6.52 (1.51-28.11), respectively]. Conclusion:The migration time is related to the prevalence of myopia of the children and adolescents of migrant workers.