BACKGROUND: Critical incidents are natural and man-made disasters arising suddenly, which are beyond the ability of the individuals to resist or control. In the situation of stress, individuals feel stuck, and are unable to control the situation.OBJECTIVE: To confirm the assessment model of stress response to critical events and the interventional effect of social support, general self-efficacy and coping efficacy.DESIGN: A randomized sampling, questionnaire-based investigation.PARTICIPANTS: We selected 1016 college students of 17 provinces or cities including Beijing, Guangzhou, Hefei, Jilin, Jiangsu, Jiangxi , Liaoning, Sichuan, Inner Mongolia, Shandong , Shanghai, Hebei, Tianjin,Wuhan, Zhejiang , Chongqing and so on as subjects. Totally 708 college students selected from the above regions received the same survey one year later.METHODS: Depression and anxiety state of the subjects were investigated with Center for Epidemiological Studies Depression Scale (CESD)and Anxiety Inventory (SAS) during SARS. Social support condition was investigated with Social Support Rating Scale, authorized by Xiao Shuiyuan. Related items were amended considering used among college students. The subscale was integrated into 3 subscales including group-support, friend-support and social support utilization. One year later, stress response to SARS was investigated again with self-made coping efficacy scale, self-esteem scale and self-efficacy scale and SARS Stress Response Questionnaire, which included 13 items measuring the students in three aspects: cognitive evaluation to SARS epidemic, such as "I believe human beings can conquer SARS in the end"; panic to SARS, like "worrying about SARS sweats me and makes me feel shiver sometimes"; and defense response to SARS, as "In order to prevent SARS, I have to wear respirator in the public". As far as cognitive, panic emotion and defense behaviors were concerned. The coping efficacy developed by the author covered 18items, such as "I'm afraid that I can not deal with things", "I have enough confidence to conquer any difficulty", and namely as friability, confidence and intelligence.RESULTS: ① The two investigated results were compared through assessment of covariation. There was a significant difference in cognitive condition, panic emotion and defense behavior; that was to say, the stress response to SARS had been obviously relieved . ② Social support and SARS stress response model x2=8.654,df=4,P=0.07;criterion fit index NFI= 1, RFI =0.997 and IFI =1, RMSEA=0.034. ③self-efficacy confirmative factor analysis showed the following: x2=0.536,df=2,P=0.765;x2/df=0.268, NFI=1, RFI=1, IFI=1 and CFI=1, RMSEA=0.000. ④The discriminating and convergent validity of coping efficacy questionnaire was as follows. The coefficient was 0.633 with general efficacy questionnaire, 0.530 with self-respect (SES), 0.481 with CESD, 0.387 with anxiety (SAS), and -0.003 with living events. ⑤ A structural equation model about general self-efficacy, coping efficacy and SARS stress response was established: x2 =2.722 df=3, P=0.437; NFI=1, RFI=0.999,IFI=1, CFI=1, RMSEA=0.068. The model fitted well. According to the data, coping efficacy affected SARS stress response negatively (the coefficient was -0.59)CONCLUSION: ① The three-dimensional assessment model assessed the stress response to critical incidents including cognitive adjustment, emotional response and behavioral tendency. The three-dimensional model stood the test while assessing SARS stress response. Compared with the assessment of emotional disorders, such as depression and anxiety, the model was more sensitive. ②Social support played a vital role in the stress response to critical incidents as a buffer or a regulator. It showed more influence on emotional disorders than on SARS stress response. ③Coping efficacy was a measurable intervening variable, which deserves more attention to in the stress response to critical incidents. Compared with general self-efficacy, coping efficacy had a greater intervening effect on SARS stress response.

To evaluate the clinical effects of rotary nickel-titanium instruments Mtwo in root canal therapy in the aged patients. Using step-back technique,80 teeth with pulpal and periapical involvement were instrumented by Mtwo in the M group, and by K file in the K group. Mtwo could keep the original curvature and flow of the root canals. No transportation, apical blockage, ledge or perforation was found in the M group. There was more complications in the K group than in the M group.The operative time was shorter and posttreatment pain seldom occurred in the M group. With rotary NiTi instruments Mtwo for seniles' root canals treatment, root canals can be prepared effectively and quickly,and is worth of clinical application.

Objective:To establish an in vitro root canal model infected by Enterococcus faecalis and to observe the morphology, distribution and relative position of Enterococcus faecalis in infected root canals.Methods: Ten human healthy premolars extracted for orthodontic reasons were collected. Following sterilization , a total of 5 specimens were aseptically transferred to separate Eppendorf tubes containing 1. 5 mL brain-heart infusion broth (BHI) inoculated with 0.1 mL Enterococcus faecalis suspension that had been adjusted to Mcfarland 5, and were incubated at 37℃ for 21 days. The other 5 specimens were as controls. The roots of all specimens were then split into two halves along the mesiodistal axis. One half was processed with light microscopic ( Brown & Brenn stain) to check the bacteria in dentinal tubules, and the other was observed with SEM to investigate the bacterial status in infected root canals. Results: Enterococcus faecalis could penetrate into the dentinal tubules about 330-1 000μm. A dense bacterial aggregation composed of Enterococcus faecalis and amorphous matrix was observed in the apical third of the root canals, whereas Enterococcus faecalis were seen free-floating or planktonic in the crown and middle third of the root canals . No microorganisms were found in the root canals of the controls. Conclusion:Enterococcus faecalis could form bacterial biofilm on the root canal walls and penetrate into the dentinal tubules. The in vitro model designed was simple, and had good practicability to make a further comparative evaluation of various antimicrobial methods in the reduction of intracanal bacteria.

Objective To construct an infectious full-length cDNA clone of enterovirus 71(EV71)and develop a technological platform for study on vaccine development as well as molecular virology of EV71.Methods According to the nucleotide sequence of EV71 strain 085 isolated in China,four pairs of primers were designed for amplification of four end to end overlapping subgenomic cDNA fragments,the cDNA fragments were directional cloned into pBluescript SK(+)vector,and the virus genome cDNA clone was obtained by ligation orderly.The rescued virus of parental strain 085 from RNA transfected host cells was identified by RT-PCR,IFA,titration as well as transmission electron microscope(TEM)after the transcription of the full-length cDNA clone in vitro.Results The full-length cDNA clone was constructed successfully,and the typical CPE was observed after its transcription into Vero cells.The rescued virus with 20-30 nm in diameter can not only be neutralized by EV71 special anti-serum but also react with anti-EV71 monoclonal antibody that virus infected cells stained with FITC can be detected by IFA.After amplification from the total RNA extraction of virus infected cells by RT-PCR with EV71 special primers,the 226 bp products can be detected.The growth curve showed that the rescued virus can propagate in Vero cells stably with a titer of 4.5 ～6.0 lgCCID50/ml during 8 passages.The plaque formed by rescued virus is identical as parental virus in morphology but smaller in size.Conclusion An infectious full-length clone of EV71 was developed successfully,which will be used for further study on pathogenesis and vaccine development of EV71.

ObjectiveTo explore the theoretical construct of network values and design the network values questionnaire.MethodsThis research was to design the network values questionnaire based on an open-ended inventory survey,overviews of former studies and counseling of experts.Through stratified sampling,832 college students were investigated by the network questionnaire.The data were examined by item analysis,factor analysis,reliability and validity analysis.ResultsThe network values was a multi-dimensional construct which had three factors.The three factors cumulative total explained variance was 50.719％,52.545％ and 50.510％.The questionnaire's internal consistency reliability was 0.931 and 0.809-0.874 for the three subscales.The questionnaire's split-half reliability was 0.902 and 0.772-0.864 for the three subscales.ConclusionThe theoretical construct of network values is rational.The questionnaire has good reliability and validity.

In recent years,the incidence of hepatocellular carcinoma (HCC) has increased with a higher mortality rate.Early detection and early treatment are essential to improving the patients' survival rate. Imaging is widely used HCC and is advantageous because it is non-invasive. The rapid development of imaging calls for higher standards in order to diagnosis hepatocarcinoma at an earlier stage so as to achieve complete treatment.This review describes the scientific progress on imaging differential diagnosis and application on pre-cancerous nodules (dysplastic nodule,DN) and small hepatocellular carcinoma (sHCC) related to hepatocarcinogenesis in cirrhotic livers.

Objective To discuss the application of internal fixation technique in eyebrow lift and infrabrow excision blepharoplasty.Methods With the incision within eyebrow or infrabrow excision incision,fixation of the eyebrow to the brow periosteum using 4-0 silk thread and then suturing the upper and lower border of the incision could lift the eyebrow and correct the ptosis of upper eyelid skin and fishtail lines.Results All the 138 cases got good results,showing that the eyebrow and upper eyelid skin ptosis and lateral fishtail lines were all corrected.Conclusions Internal fixation technique can get better results in eyebrow lift and infrabrow exicion blepheraplasty surgery.

The technique of chimeric antigen receptor-engineered T cells (CAR-T) is combined single chain antibody and T-cell activation modification and has specific and durable killing effect on tumors.It had achieved stunning results on clinical trials of B lymphocytic leukemias,B lymphomas and solid tumors.Meanwhile it also had potential risk on the off target effects,cytokine release syndrome,graft versus host disease and so on.This paper briefly reviews the principal of CAR-T cellular mechanism,advantages and clinical applications.

Objective:To investigate the patterns of microbial infection on the apical external root surfaces of treated and untreated teeth associated with chronic apical periodontitis and to study bacteria in the biofilm in order to find out the species,constitution and origination of bacteria in periapical biofilm.Methods: Ten teeth with chronic apical periodontitis from patients of the Department of Stomatology of People's Hospital,Peking University: 5 untreated teeth with a radiographically visible chronic periradi-cular lesions and 5 teeth with extensive carious lesions,radiolucent lesions of varying sizes and attached periradicular tissues were selected for study.Using aseptic techniques and sterile instruments,bacterial samples of the root canals were taken,inoculated and separated according to usual practice.After extraction,ten teeth were fixed and the apical 5 mm portion of one root was sectioned.Root tips were dehydrated,sputter coated with gold,and then examined for the occurrence of bacteria on the apical root surfaces using scanning electron microscope.Five healthy teeth with vital pulp were used as controls.Results: Microbial study showed that ten specimens yielded bacterial growth.The most prevalent bacteria were P.micros and F.nueleatum.In the 5 untreated teeth,bacterial cells were usually observed close to the apical foramen in only 1 specimen.Morphologically,these bacteria consisted of cocci.In the 5 treated teeth,a dense bacterial aggregation composed mainly of cocci and rods was observed surrounding the apical foramen of all specimens.Besides rods,other bacterial morphological types were recognized,including coaggregations of cocci and filaments,characterizing a fully developed "corn-cob".No microorga-nisms were found in the healthy controls.Conclusion:Bacterial biofilm was always present in teeth with post-treatment endodontic disease.The presence of apical bacterial biofilm is clinically important,and it may cause failure of endodontic treatment as a consequence of persistent infection.

Objective:To establish an in vitro root canal model infected by Enterococcus faecalis and to observe the morphology,distribution and relative position of Enterococcus faecalis in infected root canals.Methods: Ten human healthy premolars extracted for orthodontic reasons were collected.Following sterilization,a total of 5 specimens were aseptically transferred to separate Eppendorf tubes containing 1.5 mL brain-heart infusion broth(BHI) inoculated with 0.1 mL Enterococcus faecalis suspension that had been adjusted to Mcfarland 5,and were incubated at 37 ℃ for 21 days.The other 5 specimens were as controls.The roots of all specimens were then split into two halves along the mesiodistal axis.One half was processed with light microscopic(Brown & Brenn stain) to check the bacteria in dentinal tubules,and the other was observed with SEM to investigate the bacterial status in infected root canals.Results: Enterococcus faecalis could penetrate into the dentinal tubules about 330-1 000 ?m.A dense bacterial aggregation composed of Enterococcus faecalis and amorphous matrix was observed in the apical third of the root canals,whereas Enterococcus faecalis were seen free-floating or planktonic in the crown and middle third of the root canals.No microorganisms were found in the root canals of the controls.Conclusion: Enterococcus faecalis could form bacterial biofilm on the root canal walls and penetrate into the dentinal tubules.The in vitro model designed was simple,and had good practicability to make a further comparative evaluation of various antimicrobial methods in the reduction of intracanal bacteria.