Many active measures,such as changing teaching attitude,improving hardware conditions of laboratory,reforming teaching methods,establishing strict manage systems and using advanced teaching materials were taken.We paid high attention to train students'practical abilities and to stimulate students'interest in studying this course.We were strict with students in order to develop a good style of study and scientific research.

Based on the structure characteristics of the stretcher base of WCY2000field ambulance,this paper sets up a finite element analysis model with twotypes of beam elements.The accuracies under twotypes of elements are discussed and model method of the same structure is presented.

Objective To investigate the prevalence rate and the related risk factors of posttraumatic stress disorder ( PTSD) in the rescue paratroopers 1.5 year after Wenchuan earthquake. Methods A total of 183 rescue paratroopers who participated in disaster rescue after Wenchuan earthquake were investigated with the questionnaires composed by General state of health questionnaire, PTSD Checklist-Civilian Version ( PCL-C), Symptom Checklist-90 ( SCL-90), Self-Rating Depression Scale ( SDS) and Eysenck Personality Questionnaire (EPQ). Results Six rescue paratroopers had total PCL-C score ≥ 38 points, with the prevalence rate of PTSD for 3.28%. Total PCL-C score was positively correlated with total SCL-90 score, N score of EPQ and total SDS score (P ＜ 0. 01), but negatively correlated with E score of EPQ. Total PCL-C score showed statistical difference between injury group and uninjury group, family loss group and family integrity group, contacting corpses group and none contacting corpses group (P＜0.05 or ＜0.01). Regression analysis showed the length of military service, nervousness, family loss by earthquake, suffering injuries or contacting corpses during relief operations were the risk factors for PTSD. Conclusion The prevalence rate of PTSD in the rescue paratroopers is higher than that in normal troops (0.49% ) 1.5 year after Wenchuan earthquake, indicating that further attention should be paid to the rescue paratroopers in later period after earthquake.

Objective To investigate the CD34~+ umbilical cord blood hematopoietic stem cells (CD34~+ UBSC) transfected with interleukin 21 (IL-21) against the ovarian cancer effect in tumor-bearing nude mice. Methods CD34~+ UBSC were obtained from the UBSC by a magnetically activated cell sorting technique and then transfected with recombinant plasmid plRES2-IL-21-EGFP after the CD34~+ UBSC were proliferated in vitro. The therapeutic effect was evaluated by the size of the tumor and the life span in nude mice treated with the CD34~+ UBSC-IL-21. The expression of IL-21 and its bioactivity in CD34~+ UBSC-IL-21 and in local neoplasitc tissues were respectively detected by reverse transcription-polymerase chain reaction (RT-PCR), immune fluorescence technique, ELISA, Western blot, immunohistochemistry and splenocyte proliferative activity. The NK cell cytotoxicity and the numbers of NK cells, serum level of IFN-γ and TNF-αwere simultaneouly detected by FCM and ELISA, respectively. Results CD34~+ UBSC were cultured and transfected with pIRES2-IL-21-EGFP successfully. CD34~+ UBSC-IL-21 could inhibit the tumor growth and extended nude mice life span compared with other groups (P < 0.01). The expression of IL-21 in the neo-plastic tissue, serum level of IFN-γ and TNF-α , NK cell activity and the numbers of NK cells of mice origin and of human origin in splenocytes were increased significantly in the nude mice treated with CD34~+ UBSC-IL-21 compared with other groups(P <0.01). Conclusion The CD34~+ UBSC transfected with IL-21 have competent against ovarian cancer in tumor-bearing nude mice. The findings may establish a foundation for gene therapy of the ovarian cancer by CD34~+ UBSC-IL-21 in clinic application.

Abstract: Membrane proteins, which play a critical role in various life processes, particularly in regulating cell-cell contact and signal transduction, are closely linked to cell differentiation and maturation. Therefore, it is of great theoretical and practical significance to develop a variety of methods to thoroughly explore the interactions between membrane proteins. In addition to traditional techniques such as immunoprecipitation, newly developed proximity labeling (PL) techniques have gradually become important means to study membrane protein interaction. PL methods are based on engineered enzymes fused with bait protein to catalyze small molecules, label neighboring target proteins, and detect the interactions by flow cytometry, mass spectrometry, confocal microscopic imaging, etc. This paper focuses on the recent developments in PL techniques for studying membrane protein interactions, with a prospect of the potential future directions for research in this area.

Objective To compare the diagnostic value of white light endoscopy and intelligent scan(i-Scan)endoscopy for nasopharyngeal masses.Methods We collected 127 patients with nasopharyngeal masses from January 2019 to December 2021 and obtained biopsy pathological results.From January 2019 to December 2020,59 cases were treated with white light endoscopy,and from January 2021 to December 2021,68 cases were treated with i-Scan endoscopy.Compare the accuracy of diagnosis between the two groups based on pathological results as the gold standard;Evaluate the microvascular morphology and lesion boundaries of nasopharyngeal masses under i-Scan endoscopy,and conduct correlation analysis with pathological results.Results The specificity and accuracy of i-Scan endoscopy in the diagnosis of nasopharyngeal masses were higher than those of white light endoscopy(91.80%and 86.00%,91.17%and 86.44%),and the sensitivity was lower than that of white light endoscopy(85.71%and 88.89%),but there was no significant difference(P>0.05).The diagnostic consistency of i-Scan group was slightly higher than that of white light group(Kappa=0.619 and 0.588);The lesion site boundary score,microvascular score,and their total score in i-Scan group were positively correlated with the pathological score(r=0.429,r=0.421,r=0.460),the differences were statistically significant(P<0.05);Typical disordered and twisted submucosal vessels(SV)and branching vessels(BV)were observed in nasopharyngeal carcinoma,most benign lesions could observe dilated and regularly distributed SV and BV,regardless of pathological malignancy,no obvious intraepithelial papillary capillary loop(IPCL)was observed in the nasopharynx.Conclusion The diagnostic efficacy of i-Scan endoscopy for nasopharyngeal masses is higher than that of white light endoscopy.

Objective To introduce a new method for preparation of bioactive β-tricalcium phosphate (β-TCP) by rapid stem cell screen-and-enrich-and-combine circulating system (SECCS) and evaluate its efficacy in the treatment of fresh fractures and bone defects.Methods Twenty-two patients with fresh fracture and bone defects were treated with SECCS from July 2013 to April 2016.They were 16 males and 6 females with an average age of 52.2 years (from 27 to 81 years).There were 15 tibial plateau fractures and 7 calcaneal fractures.The average size of bone defects was 12.5 mL.Bioactive β-TCP was prepared by SECCS intraoperatively and implanted back immediately into the bone defects.Radiographic examination,Lysholm knee scoring and Maryland foot scoring were used for assessment of curative efficacy.Results The 22 patients were followed up for an average of 25.7 months (from 12 to 46 months).By SECCS,the enrichment efficiency of bone marrow stromal cells (BMSCs) reached up to 82.4％ and the cell viability was not affected.The tibial plateau fractures were re-transplanted with 13,381.3 BMSCs on average and healed after an average of 8.9 weeks (from 6 to 15 weeks).The Lysholm knee scores at one year postoperatively averaged 93.6 points (from 84 to 100 points),yielding 10 excellent cases,4 good cases and one fair case.The calcaneal fractures were implanted back with 16,677.7 BMSCs on average and healed after an average of 9.4 weeks (from 8 to 13 weeks).The average Maryland foot score at one year after operation was 93.6 points (from 85 to 98 points),yielding 6 excellent cases and one good case.Conclusion Bioactive materials prepared by SECCS are good bone grafts for fresh fractures and bone defects.

Objective:To explore the effect of the 3D printed model assisted network teaching of neurosurgery.Methods:Seventy-six probation students were divided into: 3D printed model assisted online course teaching group (test group) and traditional teaching group (control group). After 1-month online teaching, quantitative assessment and satisfaction survey were carried out. SPSS 17.0 was used for statistical analysis of variance.Results:The department graduation test (theory and operation) scores of students in the test group were (86.7±7.4) points, which was significantly higher than those in the control group (78.2±8.2) points ( t=5.56, P<0.01). The teaching satisfaction survey showed that the test group had significantly higher scores in self-evaluation of spatial imagination ( t=3.81, P<0.01), deepening understanding of neuroanatomy ( t=5.29, P<0.01), and increasing interest in clinical learning ( t=5.12, P<0.01) than those of the control group. Conclusion:Compared with the conventional online teaching methods, 3D printed model assisted online teaching helps to improve teaching quality and students' satisfaction.

Objective To investigate the relationship of miRNA gene polymorphisms with blood pressure(BP)responses to the sodium and potassium diet intervention.Methods In 2004,we recruited 514 participants from 124 families in seven villages of Baoji,Shaanxi Province,China.All subjects were given a three-day normal diet,followed by a seven-day low-salt diet,a seven-day high-salt diet,and finally a seven-day high-salt and potassium supplementation.A total of 19 miRNA single nucleotide polymorphisms(SNPs)were selected for analysis.Results Throughout the sodium-potassium dietary intervention,the BP of the subjects fluctuated across all phases,showing a decrease during the low-salt period and an increase during the high-salt period,followed by a reduction in BP subsequent to potassium supplementation during the high-salt diet.MiR-210-3p SNP rs 12364149 was significantly associated with systolic BP(SBP),diastolic BP(DBP)and mean arterial pressure(MAP)responses to low-salt diet.MiR-4638-3p SNP rs6601178 was significantly associated with SBP while miR-26b-3p SNP rs115254818 was significantly associated with MAP responses to low-salt intervention.In addition,miR-26b-3p SNP rs115254818 was significantly correlated with SBP,DBP and MAP responses to high-salt intervention.MiR-1307-5p SNPs rs1 1191676 and rs2292807 were associated with SBP and MAP responses to high-salt diet.MiR-4638-3p SNP rs6601178,miR-210-3p SNP rs12364149,miR-382-5p SNP rs4906032 and rs4143957 were significantly associated with SBP response to high-salt diet.In addition,miR-26b-3p SNP rs115254818 was significantly associated with SBP,DBP and MAP responses to potassium supplementation.MiR-1307-5p SNPs rs11191676,rs2292807,and miR-19a-3p SNP rs4284505 were significantly associated with SBP responses to high-salt and potassium supplementation.Conclusion miRNA gene polymorphisms are associated with BP response to sodium and potassium,suggesting that miRNA genes may be involved in the pathophysiological process of salt sensitivity and potassium sensitivity.