Objective:To discuss the effect of downregulating microRNA-208a(miR-208a)on the resistance of the colorectal cancer cells to 5-fluorouracil(5-FU),and to clarify its related molecular mechanism.Methods:Real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the expression levels of miR-208a and secreted frizzled-related protein 1(SFRP1)mRNA in the 5-FU-resistant colorectal cancer cell line HT-29/5-FU and its parent HT-29 cells.The HT-29/5-FU cells were transfected with miR-208a inhibitor plasmid and its negative control plasmid(inhibitor-NC),and SFRP1 small interfering RNA(si-SFRP1)and its negative control plasmid(si-NC),either separately or in combination,followed by treatment with 5-FU.The cells were divided into inhibitor-NC group,miR-208a inhibitor group,miR-208a inhibitor+si-NC group,and miR-208a inhibitor+si-SFRP1 group.MTT assay was used to detect the proliferation activities of the cells and the resistance indexes were calculated;Annexin V-FITC/PI double staining and flow cytometry were used to detect the apoptotic rates of the cells after treated with different concentrations of 5-FU;Western blotting method was used to detect the expression levels of SFRP1,β-catenin,P-glycoprotein(P-gp),and ATP-binding cassette subfamily B member 1(ABCB1)proteins in the cells in various groups;dual-luciferase reporter gene assay was used to validate the targeting relationship between miR-208a and SFRP1.Results:Compared with HT-29 cells,the expression level of miR-208a in the HT-29/5-FU cells was increased(P＜0.05),and the expression level of SFRP1 mRNA was decreased(P＜0.05).Compared with inhibitor-NC group,the proliferation activity of the cells in miR-208a inhibitor group was decreased(P＜0.05),the resistance index was decreased,the apoptotic rate was increased(P＜0.05),and the expression levels of β-catenin,P-gp,and ABCB1 proteins in the cells were decreased(P＜0.05).The dual-luciferase reporter gene assay results showed that SFRP1 was a target gene of miR-208a and miR-208a could negatively regulate the expression of SFRP1.Compared with miR-208a inhibitor+si-NC group,the proliferation activity of the cells in miR-208a inhibitor+si-SFRP1 group was increased(P＜0.05),the resistance index was increased,the apoptotic rate was decreased(P＜0.05),and the expression levels of β-catenin,P-gp,and ABCB1 proteins in the cells were increased(P＜0.05).Conclusion:Downregulation of miR-208a can improve the resistance of the HT-29/5-FU cells to 5-FU by targeting and upregulating the SFRP1 expression,thereby inhibiting the transmission of the Wnt signaling pathway.

Objective: Through statistical analysis of drug resistance and homology of Acinetobacter baumannii in geriatric department of our hospital, we can provide evidence for clinical experience in antibiotics use and nosocomial infection control. Methods: The drug resistance of Acinetobacter baumannii isolated from the elderly rehabilitation department in Ningbo Kangning Hospital from January 2017 to December 2018 was analyzed by retrospective analysis.The homology of Acinetobacter baumannii isolated from clinical isolates was detected by PCR ERIC-PCR method and agarose gel electrophoresis method. Results: The resistance rates of Acinetobacter baumannii to ciprofloxacin and levofloxacin were 41.6% and 35.4%, respectively.The resistance rates to cefepime, ceftriaxone and ceftazidime were 40.3%, 38.9% and 36.7%, respectively.The resistance rate to imipenem was 38.9%, and the sensitivity rates to cefoperazone/sulbactam, gentamicin and tobramycin were all over 70%.A total of 226 strains of Acinetobacter baumannii were genotyped by ERIC-PCR.They were mainly classified into A, B, C, D and E 5 types.Among them, 116 strains were type A, 68 strains were type B, 26 strains were type C, 8 strains were type D and E. Conclusion The resistance rate of Acinetobacter baumannii to some antibiotics in geriatric rehabilitation department is still at a high level, so we should continue to strengthen the rational use of antibiotics; at the same time, the strains are highly homologous, and there is likely to be clonal transmission in the department, so we should take more effective measures to prevent and control its transmission in hospital.

Objective To develop a ribbed,oxygen-enriched and inflatable tent to fulfill the requirements for mobile enriched oxygen supply under plateau conditions.Methods The tent was developed with ribbed skeleton,PVC material,nested structure,buffer door,channel for fresh air dispersion,exhaust recovery pipeline and etc,and the self-developed plateau oxygen enrichers were involved in to establish a mobile oxygen-enriched room.The enrichers were divided into four grades of 20,50,70 and 100 m3/h,which were used to execute 8-h oxygen-enriched fresh air dispersion in the tent.The change curves of the fractions for oxygen and carbon dioxide were compared and analyzed at 5 disperse points in the tent.Results Optimal effect was acquired with 20 m3/h oxygen enricher,the oxygen concentration reached 27％ in the tent after 8-h dispersion,while the carbon dioxide fraction was 1 800 ppm (1 ppm=l×l0-6) and it took 3-h to raise oxygen concentration to 25％.Conclusion The tent combined with 20 m3/h oxygen enricher decreases the equivalent altitude from 5 000 m to less than 3 000 m,and is hopeful to be spreaded in the plateau troops after improvement.

Objective To develop a novel stress fracture animal model system based on dynamic cyclic mechanical loading.Methods Ulnae and tibiae of rats were respectively fixed using differently shaped fixtures (including a fixed holder and a movable holder).The axial mechanical loading was applied via a linear actuator based on LabVIEW control program.During the loading process,a load cell and a laser displacement transducer were used to detect the force and displacement changes in the limbs,respectively.The two signals were sampled at real time by PC-based LabVIEW data acquisition program.A compressive loading test (peak force of 50 N) was conducted to examine the consistency and reliability of cyclic loads after completing the loading system.The loading system and an ElectroForce 3220 mechanical testing machine were respectively used to measure and compare the Young's modulus of a standard ultra-high molecular weight polyethylene (UHMWPE)cylinder to calibrate the loading system.Results The compressive loading test (peak force of 50 N) demonstrated that the mechanical loading system was able to apply consistent loads with controllable intensity and time.The calibration experiment indicated the accuracy of the loading system.Conclusion The novel mechanical loading device has characteristics of precision,scientificity and reliability,and it is approaching the real development situation of stress fracture,which may provide a reliable experimental base for exploring the precautionary measures of stress fracture.

Objective To design a test phantom for clinical routine quality control of magnetic resonance imaging (MRI).Methods The commonly used phantom such as Magphan SMR170 and Victoreen 76-903 were used for experiments with the same parameters,and the test data of all the modules were compared.The advantages and disadvantages of all the modules were analyzed,and an optimization scheme was proposed accordingly.Results The phantom could be applied to the detection of high-image-quality MRI machine,and solved the problems in positioning,size matching and etc.Conclusion The new phantom meets the demand of magnetic resonance imaging clinical routine testing,and provides a certain reference for phantom optimization design.

English for science and technology (EST) is the language medium for academic communication among scientists and technologists. The expression of EST is characterized by concise-ness, correctness, objectiveness and understandability. The EST course is regarded as a key process for the undergraduate students to reinforce the English foundation and improve the capacity of English application after their College English study. In this paper, the authors introduced an interest-motivated, output-dominated, snowballing and interactive teaching strategy, according to the accumulated experi-ence of EST teaching in the past few years coupled with the unique medicine-engineering combined characteristics for the major of biomedical engineering.

The factors for the undergraduate thesis design in biomedical engineering specialty were analyzed from the as-pects of tutor, student and administration, and some suggestions were proposed accordingly to enhance the undergraduate thesis design in biomedical engineering specialty.

Objective To investigate the clinical value of medical image-three dimensional visible system (MI-3DVS) in percutaneous transhepatic cholangioscopy lithotripsy (PTCSL) for the treatment of hepatolithiasis.Methods The clinical data of 66 patients with hepatolithiasis (55 were from the First People's Hospital of Shunde City and 11 were from the Zhujiang Hospital) were retrospectively analyzed.The images of computed tomography were three-dimensionally reconstructed with MI-3DVS.The location,number,size,shape of the stones were figured out,and the operation strategies of PTCSL were designed according to the types of the disease.The clinical value of MI-3DVS was evaluated according to the operation results and postoperative recovery of patients.All the patients were followed up via telephone or out-patient re-examination.Results Liver,biliary system,stones and blood vessels were three-dimensionally reconstructed with the MI-3 DVS,and the size,number,shape,location of the stones and location,degree,length of the biliary stricture and its anatomical relationship with adjacent blood vessels were clearly displayed.The coincidence rate of planned and actual operations was 95.5％ (63/66).The mean operation time,intraoperative blood loss,rate of stone clearance,complication rate and duration of hospital stay of 63 patients were (117 ± 9) minutes,(18 ± 1) ml,92.4％ (61/66),6.1％ (4/66) and (15 ± 4) days,respectively.All the patients were followed up till September 2012,the median survival time was 16 months (range,1-69 months),and the recurrence rate of hepatolithiasis was 9.1％ (6/66).One patient died of tumor metastasis and multi-organ dysfunction syndrome postoperatively.Conclusion MI-3DVS could effectively improve the safety and efficiency of PTCSL for patients with hepatolithiasis.

Objective: In order to understand temporal and spatial distributions of alternating electromagnetic field (AEMF) of a coil thoroughly, the 3-D finite-element models of this kind of Biomagnetic Fields are established and analyzed for the research on bioeffect of magnetic field on microcirculation. Methods: Designing CAD models, setting boundary conditions, meshing models and obtaining numerical solutions were completed all within Comsol Multiphysics in terms of the theory of electromagnetic field. Results: Axial and radial plot of spatial attenuation rate of the AEMF, which were accordance with measured data, were simulated while the temporal and spatial distributions of AEMF were acquired. Conclusion: Models of 3-D finite-element of this kind of biomagnetic fields which appeared to exactly simulate the real magnetic field were first established systematically, and solved the placing problem of magnetic fields for the research on bioeffect of magnetic field on microcirculation and provided platforms for the simulation of hemodynamic of blood flow in the magnetic field.

OBJECTIVETo understand mental health status of the students and adults in the earthquake disaster areas, as to providing guidance on intervention for post-disaster psychological crisis.

METHODSThe Self-Reporting Questionnaire (SRQ-20), an appendix of The Ministry of Health of "emergency psychological crisis intervention guiding principles", was used among 1222 victims in Wenchuan earthquake, Sichuan province. This questionnaire survey was conducted in 729 students and 493 adult victims in a randomized method. Of the 734 questionnaires distributed and received in students, 729 were validly responded with efficiency rate of 99.32%; while for adults, 496 questionnaires distributed, 496 received, 493 were valid with efficiency rate of 99.39%.

RESULTS(1) In students victims, 65% responded that they did feel "uneasy, nervous or worried", followed by "easy to be scared", "feel unhappy", "easy fatigue" and "hard to make a decision". For adult victims, 80.5% replied that they felt "uneasy, nervous or worried", followed by "feel unhappy", "easy fatigue", "difficult sleeping", "easy to be scared". (2) The average of the SRQ score of student victims was 6.58 +/- 3.99, and 6.07 +/- 4.02 for males, 7.03 +/- 3.91 for females. The average of the SRQ score of student victims was 7.36 +/- 3.98, male 6.68 +/- 3.82, female 7.99 +/- 4.03. The significant differences (t(women) = 2.985, P < 0.01; t(total) = 3.332, P < 0.01) was observed in women and the total group of students and adults. (3) The SRQ positive screening rate of students group was 46.50%, the adult group was 52.33%, SRQ >or= 7 points and SRQ < 7 sub-group of students and adults of the total score there were significant differences (t(1) = 39.771, P < 0.01; t(2) = 31.961, P < 0.01). SRQ >or= 7 sub-group of students and adult women in between there was a significant difference (t = 23.641, P < 0.01), SRQ < 7 sub-group of students and adults in general and women there were significant differences (t(1) = 3.092, P < 0.01; t(2) = 2.911, P < 0.01). (4) SRQ scores with gender and age had had a positive relation (r(SRQ total-sex) = 0.118, P = 0.000; r(SRQ total-age) = 0.103, P = 0.000).

CONCLUSIONThe emotional suffering symptoms of students victims and adult victims should be "nervous, unhappy, vulnerable on issues such as fatigue", the adult group had a higher symptom rate than the group of students, the mental health was more serious than that of students, as influenced by some factors including age and gender. Students, being a special population group should be paid more attention to focusing a designated behavior intervention, as a planned manner of intervention.

Adult ; Child ; China ; Disasters ; Earthquakes ; Female ; Humans ; Male ; Mental Health ; Middle Aged ; Stress, Psychological ; epidemiology ; Students ; psychology ; Surveys and Questionnaires