Tumor vaccine is one of the most promising therapeutic strategies in tumor immunotherapy. It promotes the antigen presentation process by delivering tumor antigen and then activates the anti-tumor immune response. As a new class of vaccines, messenger RNA (mRNA) vaccines can activate the immune system to achieve the purpose of immunotherapy by delivering the mRNA sequence of a specific antigen into the body and expressing the corresponding antigen protein. Compared with traditional vaccines, mRNA vaccines have the advantages of a short production cycle, high effectiveness, and strong immunogenicity. In recent years, the application of mRNA vaccines in tumor immunotherapy has attracted widespread attention, but the instability and low delivery efficiency of mRNA limit its application. Nano delivery system can effectively solve the problem of mRNA vaccine delivery, greatly promote the research process and clinical application of mRNA tumor vaccines, and has become a hot spot in the research of mRNA vaccines. In this review, we introduced the mRNA tumor vaccines, focusing on the application of nano delivery system in mRNA tumor vaccines, in order to provide new ideas and new methods for the efficient delivery of mRNA tumor vaccines and tumor immunotherapy.

Objective To study the relationship between static duration and bacteria reproduction of pure water from the RO purifier. Methods The original structure of RO purifier was modified by installing additional UV lights and ozone disinfector respectively. Bacteria reproduction in the effluent from RO purifier and modified RO purifier was detected after different static duration. Results The total count of bacteria in the fresh pure water was 20 cfu/ml which was up to the standard of pure drinking water CJ 94-1999. However the total count of bacteria in the pure water will be more than 50 cfu/ml after the pure water was stored inside the tank for six hours, which was not up to the standard of CJ 94-1999. Both ultraviolet rays and ozone could prolong the static duration of pure water, and the efficacy of ultraviolet rays was better than ozone. Conclusion UV light should be installed in RO purifier, the disinfected pure water by UV should be used in 16 hours after disinfection.

Objectives: To explore the influence of exercise training on the arterial baroreflex sensitivity （BRS）and correlation between blood pressure and BRS in spontaneously hypertensive rats (SHR). Methods: Male SHR（n=20）and normotensive Wistar rats（n=20）were randomly assigned to normality group and exercise group, n=10 in each group. Rats in two exercise groups received treadmill training at a speed of 20 m/min for 60 min/d, 6 d/w for eight weeks. Systolic blood pressure (SBP) and heart rate (HR) were measured using a tail-cuff method in a conscious state. Intravenous injections of phenylephrine (PE) and sodium nitroprusside (NP) were used to induce depressor and pressor reflex respectively. The ratio of HR over mean arterial pressure (MAP) (HR /MAP) after administration of PE or NP was regarded as an index of depressor reflex sensitivity (BRS-PE) and pressor reflex sensivity (BRS-NP). Results: After eight-week exercise training, compared with SHR normality group, there were significant reduction in resting SBP [(180±8.5) mmHg vs. (163.6±10.7) mmHg] and in HR [(368.4±13.3) beats/min vs. (345.0±9.8) beats/min] in SHR exercise group, P<0.01 both. However, there was no significant difference in resting SBP between Wistar exercise and normality groups (P>0.05), compared with Wistar normality group, there was significant reduction in HR [(362.2 ± 13.0) beats/min vs. (343.9 ± 10.2) beats/min, P <0.05] in Wistar exercise group. Compared with SHR normality group, there were significant rise in BRS [BRS-PE: (0.89 ± 0.13) bpm/mmHg vs. (1.32 ± 0.22) bpm/mmHg, BRS-NP： (0.60± 0.09) bpm/mmHg vs. (1.21± 0.26) bpm/mmHg, P<0.01] in SHR exercise group, but still lower than those of Wistar normality group [BRS-PE: (1.96±0.23) bpm/mmHg, BRS-NP: (1.32±0.17) bpm/mmHg]. Pearson linear correlation analysis indicated that MAP was significantly inversely correlated with BRS (r=-0.734, P<0.01) in SHR normality and exercise group. Conclusion: Exercise training may significantly decrease SHR blood pressure; it is related to improved baroreflex sensitivity induced by exercise, indicating that enhanced baroreflex may be an important mechanism of exercise therapy in hypertensive patients.

Objective : To investigate the injury characteristics among primary and middle school students in Panyu District, Guangzhou City, so as to provide the evidence for developing the strategies for prevention and control of injuries. Methods: The data of 6 to 18 years old primary and middle school students with initial diagnosis of injury at Panyu District Central Hospital from 2014 to 2019 were collected. The basic characteristics of injury cases, the causes, time and place of injury development were analyzed by a descriptive epidemiological method. Results: Totally 10 833 primary and middle school students with injury were reported in Panyu District from 2014 to 2019, including 7 401 boys and 3 432 girls, with a boy/girl ratio of 2.16∶1. The injury predominantly occurred in primary school students (6 903 cases, 63.72%). The causes of injury mainly included fall (4 457 cases, 41.14%), animal injury (2 593 cases, 23.94%), blunt injury (1 682 cases, 15.53%), knife/sharp instrument injury (923 cases, 8.52%) and traffic injury (731 cases, 6.75%). The place of injury development mainly included home (4 267 cases, 39.39%), school and public place (3 184 cases, 29.39%), and road/street (1 854 cases, 17.11%). The injury predominantly occurred from August to October (3 289 cases, 30.36%), and the activities at the time of injury mainly included leisure activities (3 860 cases, 35.63%), life activities (2 662 cases, 24.57%) and sports (1 929 cases, 17.81%). The characteristics of injury mainly included contusion/abrasion (4 528 cases, 41.80%), sharp instrument/bite/open injury (4 019 cases, 37.10%) and fracture (871 cases, 8.04%), and the upper limb was the main injury site (3 552 cases, 32.79%). There were 9 877 cases with mild injuries (91.18%), and 10 451 cases left hospitals after seeing a doctor (96.47%). Conclusions Fall is the main causes of injury among primary and middle school students in Panyu District, and boys and primary school students are high-risk groups for injury. Family prevention should be emphasized, and health education pertaining to injury should be intensified among students during the long holidays and leisure activities.

rvice employees had a low scores as comparing with their salaries, benefits and workloads.And 28.2% employees had once the idea of resigning.

Objective To objectively evaluate the intrusion effects on the maxillary incisors of implants versus conventional method(J-hook headgear ,utility arch) .Methods Such online databases as Cochrane library ,PubMed ,EMbase ,VIP ,Wanfang and CNKI were searched by randomized control test and prospective case controlled study about implants vs conventional anchorage for the maxillary incisor intrusion .After study selection ,assessment and data extraction conducted ,meta-analyses were performed by u-sing the RevMan 5 .1 software .Results Totally 11 studies were included ,6 studies involving 154 patients were included in the J-hook headgear group ,5 studies involving 127 patients were included in the utility arch group .The results of meta-analyses showed that :(1)Compared with the J-hook headgear ,implants had more decrement in the distance of upper center incisior cutting to palatal plane(P<0 .001) ,more decrement in overbite(P=0 .001) ,shorter treatment time (P<0 .001) ,less increase in SN-OP angle(P=0 .004) ,less decrement in distance of maxillary molar cusp to palatal plane (P=0 .020);There was no statistically significant differ-ence in overjet ,root resorption(P>0 .05) .(2)Compared with the utility arch ,implants had more decrement in the distance of the center of resistance of the upper incisor to palatal plane (P=0 .010) ,less increase in U6-PP angle (P<0 .001);There was no statis-tically significant difference in the distance of upper center incisior cutting to palatal plane ,U1-PP angle ,the distance of upper first Molar cutting to palatal plane ,sagittal position of the mesial tip of the upper first Molar ,overbite ,overjet ,course of treatment ,root resorption(P>0 .05) .Conclusion The implants anchorage intruded the maxillary incisor was better than conventional method (J-hook headgear ,utility arch) ,it has more incisor intrusion ,shorter treatment time and more comfortable for the patients ,there was no difference in root resorption between the two groups .

Objective: To study the immunotherapeutic effect on the esopgageal adenocarcinoma mediated by gp96-peptide complexes isolated from the same kind of tumor. Methods: gp96- peptide complexes were purified from nude mice tumors burdened by subcutaneous injection of human esophageal adenocarcinoma cell line SEG-1 . gp96-peptide complexes were carried by the dendritic cells(DC) induced from human peripheral blood mononuclear cells to prepare gp96-DC vaccine. The proliferation of lymphocytes was tested with trypan-blue stain. The quantity of interferon-?(IFN-?) released from cytotoxic T lymphocytes (CTL) was detected with ELISA method. The killing effect of CTL on target cell SEG-1 was measured with MTT. Results: We obtained 120 ?g gp96 from 55 g tumor tissue. DC, gp96, and gp96-DC all could elicit the proliferation of lymphocytes and make them becoming into CTL which released IFN-? and showed different degrees of killing effect on target cell SEG-1. gp96-DC has the strongest eliciting effect among them. At the ratio of E(effect) to T(target) as 40∶1,the killing rate was 68%.No significant difference between the effects of CTL induced by DC alone and of lymphocytes without specific antigen on SEG-1 and K562 cells. Conclusion: The gp96-peptide complexes from tumors can improve the effect of eliciting lymphocyte proliferation of DC and make the lymphocyte becoming into CTL more effectively.These CTLs show prominent killing effect on the target tumor cells.