As a social problem,college students'Internet Addiction has drawn attention widely.A lot of domestic areas and departments have done research on college students' Internet Addiction and achieved some sucess.On the basis of retrieval of papers on students' Internet Addiction,this article analyzes former research and brought up some proposals for the future research aimed at its deficiences.

Objective To investigate lymph node metastasis on the middle and lower segment of lⅡ and Ⅲ stage of esophageal squamous cell carcinomas,understand the factors influencing the lymph node metastasis,and provide the basis for the key areas of lymph node cleaning.Methods A retrospective study was made on the specimens of 186 patients who were middle and lower segment of Ⅱ and Ⅲ stage of esophageal squamous cell carcinomas,who had underwent radical operation through left thoracic,thoraco abdominal two field lymph node cleaning.All the cases were patients from April 2010 to December 2013 at the Inner Mongolia Medical University Clinical Medical College of Chifeng.Results A percentage (67.9％) of patients (126/186) was found with lymph node metastasis.A total of 4259 lymph node was dissected,with an averaged cleaning of (22.9 ± 8.1) lymph nodes for each case.A total of 622 lymph nodes (14.6％ =622/4 259) existed metastasis.The rate of mediastinum metastasis for middle and lower segment of esophageal cancer was 56.1％ and 16.5％,respectively.The rate of metastasis to the lower mediastinal lymph nodes was 34.6％ and 54.4％,respectively.The rate of metastasis to the celiac lymph nodes was 23.4％ and 46.8％,respectively.A significant difference was found in the metastasis locations of middle and lower segment of esophageal carcinomas (P ＜ 0.05).The top three locations of lymph node metastasis in the middle segment of esophageal squamous cell carcinomas were the lymph nodes of left artery paraesophageal,carina,and gastric bypass.The top three locations of lymph node metastasis in the lower segment of esophageal squamous cell carcinomas were paraesophageal,cardia,and gastric lymph nodes.The depths of tumor invasion,differentiation,intravascular cancer embolus were statistically significant effect on lymph node metastasis rate (P ＜ 0.05).Tumor location,and lesion length had no significant effect on the lymph node metastasis rate (P ＞ 0.05).Conclusions The lower segment of Ⅱ,Ⅲ stage esophageal squamous cell carcinoma with lymph node metastasis occurs in the lower mediastinal and abdominal lymph nodes.The middle segment Ⅱ,Ⅲ stage esophageal squamous cell carcinoma with lymph node metastasis occurs in the thoracic and abdominal lymph nodes with Jump transfer characteristics.The lymph node cleaning of the mid-dle segment includes the left artery near the stomach,paraesophageal,and carina lymph node.The lymph node cleaning of the lower segment includes paraesophageal,cardia,and gastric lymph nodes.The metastasis rate of vascular tumor thrombus is related to the depth of tumor invasion and differentiation degree.

Objective To investigate the gene mutation in a pedigree with pachyonychia congenita typeⅡ(PC-Ⅱ)and to explore the relationship between the mutation and clinical manifestations.Methods The exon1of K17gene of genomic DNA from peripheral blood was amplified by PCR,and the PCR products were sequenced by automated sequencing system.Results In all the3patients of the pedigree with PC-Ⅱ(2patients presented as delayed-onset PC at4and15-16years of age respectively),the codon92(AAT)of K17gene was mutated as AGT,which caused missense mutation(N92S)in the1A domain of keratin17,but the2unaffected members of the pedigree and50unrelated controls had no such mutation.Conclusions Mutation of N92S in the1A domain of keratin17exists in this pedigree with PC-Ⅱ.Our results indicate that mutation in the1A domain of keratin17can present as delayed-onset pachyonychia congenita.Therefore,the site and type of keratin mutation are not the sole determinant of the age of onset for PC-Ⅱ,there may be other genetic and/or environmental factors that determine the age of onset of PC-Ⅱ.

Internal fixation is one of the most important treatments for fractures.The stability of screws in internal fixation can be influenced by bone mineral density,quality of pilot holes,improper structure and surface characteristics of screws chosen,insertion torque,insertion angle,and screws unfit for the bone holes.Internal fixation of fractures can fail due to the instability of screws.This paper,on the basis of a comprehensive review of the studies on all the above factors influencing the screw stability,proposes effective methods to enhance screw stability so as to improve surgical outcomes of fracture internal fixation.

Objective To identify the influencing factors for rural doctors′ training effect,and suggest on the improvement of such training.Methods On the basis of rural doctors′ survey,the theory of pre-intervention was used to probe into the influencing factors for such training in five dimensions of attention notice,mega-cognitive strategies,advance organizer,goal orientation,and preparatory information.Results 73.2% of the groups were found with satisfying effect.In the single factor analysis,comparison of training effect involving such factors as age,gender,length of work life and pre-intervention revealed statistical significance(P<0.05).As shown in the logistic regression analysis,High motivation in meta-cognitive strategies,Clear goals in goal orientation,Tiered and categorized training in advance organizers,and Practical learning in preparatory information,as well as variants like age would influence rural doctors′ training effect significantly.Conclusions The key to better training effect lies in better motivation of the trainee,setting correct training goals,emphasis on the practicability of training contents and,the pertinence of the training objects.

Objective To prospectively study the clinical diversity of the middle and lower segment of stage of esophageal cancer patients who accepted the thoracoscopic combined with laparoscopic esophagectomy ( TLE) between Mongolian and Han nationalities in Inner Mongolia , to further clarity the feasibility of TLE.Methods 92 consecutive cases of middle and lower segment of stage of esophageal cancer patients of Mongolian and Han were selected,and the patients accepted the TLE ,including 41 cases of Mongolian and 51 cases of Han.The postoperative pain was evaluated with the visual analog scale (VAS) at 1-14d after operation,and the postoperative complication , the hospitalization of postoperation and the postoperative pathological situation were compared .Results Compared with the Han patients,the postoperative pain of Mongolian significantly reduced ,duration of postoperative of pain significantly shorter in the 1-5 d after surgery(P <0.05).Mongolian patients turned to mild pain in the second day of the postoperative period,and Han turned to mild pain in the fourth day after surgery .The postoperative pain in the 6-14 d after surgery of the Mongolian was not significantly different from Han (P >0.05).The Mongolian had lower incidence rate of postoperative complication compared with Han (9.8% vs.27.5%,χ2 =4.522,P <0.05).For example,the incidence rates of respiratory complications in Mongolian patients ,such as pulmonary infection,atelectasis and the occurrence of pleural effusion that need to be treated were significantly lower than those in Han (7.3% vs. 23.5%,2.4% vs.15.7%,4.9% vs.19.6%,P <0.05).There was no statistically significant difference in the incidence of other complications(P >0.05).The postoperative hospitalization of Mongolian was significantly shorter than that of Han[(11.9 ±1.2) d vs.(15.5 ±1.0) d,t =-15.811,P <0.05].No significant difference in the total number of cases of lymph node dissection ,the abdominal lymph node dissection and the chest lymph node dissection . The number of the regional lymph nodes metastasis of Mongolian was higher than that of Han [(3.9 ±0.7) vs. (1.8 ±0.7),t =13.460,P <0.05],most of which were poorly differentiated (6 /25/10 vs 20 /20 /11,χ2 =7.139, P <0.05).Meanwhile,the incidence rates of cancer embolus in the vasculature and nerve invasion of Mongolian were higher than those of Han(75.6% vs.47.1%,70.7% vs.17.6%,χ2 =7.706,26.418,all P <0.05).Conclusion The Mongolian were more easily tolerant to the TLE,which has the advantages of reducing pain ,trauma,rapid recovery, satisfactory curative effect and the lesser postoperative complications .The degree of the malignancy of esophageal cancer of Mongolian was higher than Han .Mongolian who suffered from esophageal cancer needed earlier discovery , earlier treatment and further research of the causes of difference .

Objective:To probe the diagnostic performance of the combined evaluation of stenosis and plaque characteristics based on coronary computed tomography angiography (CCTA) in identification of myocardial ischemic lesions, using the invasive coronary angiography (ICA)-based fractional flow reserve (FFR) as the gold standard.Methods:From November 2018 to March 2020, the patients with suspected or known coronary artery disease and scheduled for ICA at 5 clinical trials centers were enrolled in this study. All the patients underwent CCTA, ICA and FFR in turn in one week. The luminal stenosis and plaque characteristics were measured and assessed including plaque burden, volume ratios of calcification and non-calcification, lesion length and CT vulnerable features. All culprit vessels were divided into FFR≤0.8 and FFR>0.8 groups, and the parameters of plaque characteristics were compared. The correlation of ischemic lesions with CCTA stenosis and plaque characteristics was analyzed by the logistic regression analysis. The ROC curve was used to evaluate the sensitivity and specificity of CCTA stenosis rate and plaque characteristics, meanwhile the area under curve (AUC) of each parameter was compared by Delong test.Results:Three hundred and sixty-six culprit vessels in 317 patients were analyzed in this study (169 vessels in ischemia group and 197 in nonischemia group). The plaque burden [34.3% (30.3%, 38.8%) vs. 32.4% (28.5%, 37.9%); Z=-2.622, P=0.009], proportion of CT vulnerable features [26.9% (45/169) vs.11.7% (23/197); χ 2=15.311, P<0.001] and lesion length [22.1 (14.4, 35.0) mm vs. 17.6 (11.0, 26.0) mm; Z=-4.388, P<0.001] in FFR≤0.8 group were higher than those in FFR>0.8 group. The results of logistic regression analysis revealed that CCTA stenosis, lesion length, and CT vulnerable features were significant predictors for myocardial ischemia (OR values: 3.794, 2.461, 1.027; P<0.001, P=0.002, P=0.002). The diagnostic performance of CCTA ≥50% stenosis alone in identification of ischemic lesions was low (AUC=0.625). When it combined high-risk plaque characteristics and lesion length, the AUC was improved to 0.714 with a statistical significance. Conclusions:CCTA stenosis, lesion length, and CT vulnerable features are major predictors in identification of myocardial ischemic lesions, and the combination will significantly improve the diagnostic performance of CCTA ≥50% stenosis.

Objective: To understand pneumonia mortality in children aged 0-14 years in China in recent 15 years, and to provide reference for child pneumonia prevention and treatment. Methods: Based on the death data from China Statistical Yearbook 2005-2019, pneumonia mortality in urban and rural children aged 0-14 was extracted and the standardized mortality was calculated, and the trend of mortality was fitted by Joinpoint regression model. Results: The crude mortality rate of child pneumonia in urban and rural areas showed an increasing trend, while the standardized mortality rate showed a fluctuating downward trend. Joinpoint regression showed that the mortality rate of pneumonia in urban and rural children showed a monotonous downward trend, and there was no turning point. The overall APC of pneumonia mortality of urban children was -3.4, that of boys and girls were both -3.5. Trend for annual changes in urban areas were found significant among total sample and boys (both P <0.05). The overall APC of pneumonia mortality in rural children was -7.8, that of boys and girls were -7.1 and -7.8, respectively. Trend for annual changes in rural areas were found significant among total sample and boys(both P <0.05). There was no significant differences in the trend of mortality between urban and rural groups. Conclusion During 2005 to 2019, child pneumonia mortality in urban and rural areas in China shows a downward trend, which is relatively balanced in urban and rural areas. Further strengthened pediatric pneumonia treatment and management are expected to reduce the pneumonia mortality.

Objective:To analyze the grid management strategy of medical alliances in Rizhao city, Shandong province, and to provide references for improvement of this policy.Methods:In August 2020, semi-structured interviews were conducted with 31 managers of three medical alliances in Rizhao city, regarding the objectives, specific measures, problems and influencing factors of the grid layout of the medical alliances. The grounded theory was used to sort out the interview data, along with the Mazmanian-Sabatier model for further analysis.Results:The analysis resulted in 8 main categories and 19 sub-categories, including theoretical and technical support, target group characteristics, policy causality theory, current status of policy directives, inter-agency relations, socioeconomic conditions and technology, public attitudes, and media campaigns. On this basis, a theoretical framework for the implementation of the grid layout of medical alliance was formed based on the Mazmanian-Sabatier model.Conclusions:The socio-economic conditions and technologies for implementing the grid-based management of medical alliances in Rizhao city were relatively mature, enjoying strong public support and good social response. But on the other hand, there were still such problems as unclear policies, imperfect mechanisms for synergy of interests among different subjects, and incomplete supporting policies. In the future, it is expected to form a policy implementation synergy, introduce supporting policies and strengthen primary teams building, in order to ensure the orderly promotion and long-term implementation of the policy.

Objective: To understand the incidence and mortality of drowning and secular trend among children aged 0-14 from 1990 to 2019 in China, so as to provide reference for drowning intervention among children in China. Methods: Based on data of drowning incidence and death in 0-14 years old children in China in 1990-2019 years Global Burden of Disease (GBD 2019) database, the standardized rate was calculated by the world standard population, and the trend of incidence rate and mortality rate was fitted by Joinpoint regression model respectively. Results: From 1990 to 2019, the overall incidence of drowning among children aged 0-14 years in China decreased from 37.17/100 000 to 12.54/100 000, a relative decrease of 66.26%; the standardized incidence rate decreased from 21.78/100 000 to 14.98/100 000, a relative decrease of 31.22%. The incidence rate and standardized incidence rate of drowning in children showed an increasing after decreasing trend, with decreasing mortality and standardized mortality rate. Joinpoint regression showed that the incidence rate of standardized AAPC for child drowning was -1.3, -2.5 for males and 0 for females. The overall standardized mortality rate of drowning was -3.9, male was -3.6, female was about -4.5 , the trend changes were statistically significant ( P <0.05). The incidence rate and mortality rate of male were higher than that of female, and there was significant difference between male and female groups ( P <0.05). Conclusion Significant progress has been made in child drowning prevention and control, with substantial decreasing in the incidence rate of child drowning. However, considering recent slight increase in drowning incidence, effective measures should be developmed including risk factors, vulnerable population to further control the incidence and mortality of child drowning.