Objective:To investigate the relationship between simple Chiari malformation type I (CMI) and atlantoaxial instability from the imaging point of view.Methods:A retrospective analysis were performed on 46 patients diagnosed with simple CMI from January 2014 to December 2020. Forty-six normal people matched for age and sex were selected as the normal control group, while 30 patients with atlantoaxial dislocation were selected as the dislocation group. The degree of atlantoaxial joint degeneration in each group was assessed according to Weishaupt degeneration grading; the atlantoaxial joint angulation angle was measured in the control group of patients with simple CMI; and the sagittal imaging parameters of cervical spine X-ray were measured, including C 0-C 1 Cobb angle, C 0-C 2 Cobb angle, C 1-C 2 Cobb angle, C 1-C 7 Cobb angle, C 2-C 7 Cobb angle, C 7 Slope, C 2 Tilt, spino cranial angle (SCA), and C 2-C 7 sagittal vertebral axis (SVA). All radiographic parameters were measured twice independently by two spine surgeons, and intraclass correlation coefficient (ICC) were determined to demonstrate intra- and inter-observer reliability. Results:ICC ranged between 0.842 and 0.974 in the current study, demonstrating "excellent" reliability of radiographic measurements. No significant difference was noted regarding age and the distribution of genders among the three groups. There were significant differences in the distribution of Weishaupt degeneration grading of atlantoaxial joints between simple CMI, normal and dislocation group ( H=53.68, P<0.001 on the left side; H=43.39, P<0.001 on the right side). There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and dislocation group (left, Z=6.60, P<0.001; right, Z=6.29, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and simple CMI patients (left, Z=5.31, P<0.001; right, Z=4.13, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between simple CMI and dislocation group (left, Z=3.20, P=0.001; right, Z=3.15, P=0.002). There were significant difference in the angulation angle of the atlantoaxial articular surface between the normal group and simple CMI patients (left, Z=3.32, P<0.001; right, Z=5.74, P<0.001). There were significant differences in C 0-C 1 Cobb angle ( t=2.41, P=0.018), C 1-C 7 Cobb angle ( t=2.88, P=0.005), C 2-C 7 Cobb angle ( t=3.29, P=0.001), and C 2-C 7 SVA ( t=2.87, P=0.005) between the normal group and simple CMI patients, but there was no significant difference in other parameters. Conclusion:The degree of atlantoaxial joint degeneration in patients with simple CMI is higher than that in normal people, the angulation angle is larger, and the cervical lordosis is larger, suggesting that there may be atlantoaxial joint instability. This study provides further evidence that Chiari malformation type I is associated with atlantoaxial instability.

Objective:To establish an Epstein-Barr virus-transformed peripheral blood B cell line (BCL), and explore its phenotypic characteristics, the ability to secrete antibodies and cytokines, and the ability to present hepatitis B virus (HBV) antigen peptide.Methods:Peripheral blood mononuclear cells (PBMCs) were isolated from patients with HBV infection. Epstein-Barr virus supernatant was incubated to construct BCL. The expression of CD19, CD138, CD38, CD27 and the production levels of IFN - γ, IL-10, IL-6 were detected by flow cytometry. BCL loaded with HBV antigen peptide was incubated with in vitro-expanded autologous T cells. Intracellular staining was used to detect the level of interferon-gamma produced by T cells.Results:Compared with untransformed peripheral blood B cells, BCL had high expression levels of CD138, CD38 and CD27, and the difference was statistically significant ( P < 0.05), while the level of IL-6 production was decreased, and the difference was statistically significant ( P < 0.01). BCL loaded with HBV antigen peptide had significantly enhanced the production of interferon-gamma by in vitro-expanded autologous T cells, and the difference was statistically significant ( P < 0.01). Conclusion:BCL highly expresses CD138, CD38 and CD27, but its ability to produce IL-6 decreases. BCL can improve the immune response efficiency of HBV-specific T cells to HBV antigen peptide, and serve as a new tool for hepatitis B immune research.

Aiming at the medical practice problems of the surgical steel medical instruments, such as the crevice corrosion, the poor mechanical compatibility and the Ni, Cr plasma exudation, the laser deposition of Ti-6Al-4V alloy cladding layer at the local functional area as alternative coating was proposed and realized as a new process method. The accurate element content and good formability Ti-6Al-4V cladding powder was chosen, the low power and high duty cycle optimized laser process was adopt, the alternative coating of good fusion and low dilution was prepared. Through the elemental line scanning, the interface microstructure analysis and the experiments of basic mechanical properties, the basic properties of the cladding were characterized and verified. The experiments results showed that, the Ti, Al and V contents of the top coating were respectively about 88%, 4.9% and 3.9%, no sensitizing ions such as Cr and Ni were detected. Initial equiaxed α phase, flake β phase dist were distributed in the coating and interface, the α' martensite was precipitated at the boundary of the flake β phase, some refined granular β phase dispersion pinned to the grain boundary of basket structure. The microhardness of cladding layer was 352.08~312.76 HV_0.1. The friction coefficient of the cladding layer was about 0.22~0.65. A new technology and method reference for improving and upgrading the performance of surgical medical devices is provided by this research.
Alloys ; Corrosion ; Materials Testing ; Steel ; Titanium

Objective: To analyze the characteristics of the "Interner Plus-based AIDS Comprehensive Prevention Service System" among MSM who frequently using the Internet in Guangzhou. Methods: An online survey was conducted among MSM who were recruited through gay-website portals between August and September, 2018 in Guangzhou, to collect information regarding the use of and attitudes on the "Interner Plus-based AIDS Comprehensive Prevention Service System" . Logistic regression was used to explore the association between the use of Internet intervention tools and related behavioral characteristics. Information on the awareness of AIDS, HIV testing, and condomless anal sex behavior were compared between the core or non-core services users. Results: A total of 777 Internet-based MSM were recruited as participants including 638 men (82.1%) as core service users. MSM were satisfied in using the the "Interner Plus-based AIDS Comprehensive Prevention Service System" while more than 80.0% of the users felt that the tools were helpful in: increasing the HIV awareness, promoting test uptake, and reducing those related risk behavior. Comparing with those who did not use the tools, the users showed higher rates in practising condomless anal intercourse (1.50-1.86 times), commercial sex with men (11.60-21.21 times), and unprotected vaginal intercourse (13.62-20.67 times), in the last 6 months. Proportions of core service users appeared as: [96.6% vs. 74.8%, aOR (95%CI): 8.80 (4.85-15.97)] on HIV testing, [56.4% vs. 22.3%, aOR (95%CI): 4.54 (2.94-7.02)] on regular HIV testing and [86.2% vs. 80.6%, aOR (95%CI): 1.75 (1.06-2.89)] on awareness of HIV knowledge respectively, which were all significantly higher than the non-core service users. Conclusions The frequent Internet using MSM in Guangzhou claimed to have had high acceptance and satisfaction on the local Internet HIV intervention service tools. The "Internet Plus-based AIDS Comprehensive Prevention Service System" had effectively reached the high-risk subgroups of MSM, increasing the awareness on related risk and promoting testing on HIV.

Objective: This article was to evaluate the applicability and feasibility of "Lingnanzhun" -an "Internet Plus-based HIV Self-testing Tool" targeting MSM in Guangzhou. Hopefully, the results could be used to improve the existing HIV testing services and to support the implementation and scale-up of HIV self-testing programs. Methods: Data were collected from a survey on HIV testing preferences among the Internet-using MSM in April to June, 2015. Univariate and multivariate logistic regression analysis were applied to identify factors associated with the use of HIV self-testing service provided by Lingnanzhun. Information related to the users of Lingnanzhun during September 2014 and December 2018 was also collected. Results: 769 MSM were recruited as participants. Of them, age distribution was 16-77(28.6±6.8) years old, 88.3%(679/769) were unmarried, 42.2%(325/769) were registered residents of Guangzhou, 82.1%(631/769) had university or college education. Among them, 195 (25.4%) used the HIV self- testing program of Lingnanzhun while 574 (74.6%) using the clinic service. Compared with the clinic service users, the Lingnanzhun users showed the following characteristics: longer experience in the MSM community ≥10 years (32.8% vs. 20.9%, 64/195 vs. 120/574); having male casual sexual partners ≥2 (42.1% vs. 29.6%, 82/195 vs. 170/574); having group sex (6.2% vs. 2.6%, 12/195 vs. 15/574) and having commercial sex with men (13.8% vs. 3.0%, 27/195 vs. 17/574). Data from the Lingnanzhun users showed that a total of 3 000 users had practised 5 038 times of self HIV-testings. 11.4% (343/3 000) of the Lingnanzhun users had never been tested. Conclusions It was applicable and feasible to provide Internet-based HIV self-testing service to MSM as a significant complement to the traditional facility-based HIV testing services. It was also useful in accessing those who were having higher risk or had never received HIV testing so as to increase the testing uptake and the frequency.

Objective: To analyze the characteristics of levels related to the risk through self-evaluation system, among MSM users in Guangzhou, between 2015 and 2017. Methods: Between 2015 and 2017, data was collected from the users of a self-evaluation system network related to HIV infection, based on the previous 'HIV health risk appraisal model’. Information on risk factors was collected to calculate the scores and levels of risks and to estimate the incidence of HIV. Taking the reference of R value on risks as (R=0.9-1.1) in general population. The ones with very low risk, with low risk, moderate risk, high risk and very high risk were set as R≤0.5, 0.5<R≤0.9, 0.9<R≤1.1, 1.1< R≤2.0 and R>2.0, respectively. The scores of modifiable risk factors were compared with different subgroups of MSM. Results: A total of 4 601 MSM were involved in this study, with the following features presented as: aged 16-64 (28.38±7.11) years, proportions of residence from Guangzhou, Guangdong province or other provinces as 38.6%(1 776/4 601)、35.4%(1 629/4 601) and 26.0%(1 197/4 601), 59.6%(2 742/4 601) received bachelor or above degrees. 81.3%(3 741/4 601) of them claimed as having homosexual orientation. R values of risk level on very low risk, low risk level, moderate risk, high risk and very high risk appeared as 12.9%(594/4 601), 50.9%(2 342/4 601), 17.0%(783/4 601), 14.8%(682/4 601) and 4.3%(200/4 601), respectively. Scores of modifiable risk factors decreased year by year (P<0.05), among MSM in this study. In either of the groups that experiencing insertive or receptive sex, the ones with heterosexual orientation presented the highest scores of modifiable risk factors (P<0.05). Conclusions The risk levels on HIV infections called for special attention among the users of the self-evaluation network system. Among the MSM that carrying either insertive or receptive sex role, the ones with heterosexual orientation had the highest risk levels and scores of modifiable risk factors in Guangzhou. Further study should be explored to better understand the causes of related risks.

Objective: To evaluate the effectiveness of the "Internet Plus-based AIDS Comprehensive Prevention Service System" among men who have sex with men in Guangzhou. Methods: Data through case-reporting and follow-up programs on MSM HIV/AIDS in Guangzhou was collected from the China Information System for Disease Control and Prevention, which including those from the referral and follow-up treatment compliance programs in 2008-2014 (pre-treatment) and 2017-2018 (post-treatment). According to the types of care services, three groups were set as: with "Internet Plus" service, with 'HIV counseling/testing service’ or with 'routine medical service’. General Estimating Equation (GEE) was used to analyze the follow up situation of HIV/AIDS cases, annually. Cox proportional hazard regression model was used to analyze the proportions of treatment referral, within the 30 days of diagnosis. Results: Before the implementation of immediate treatment after HIV diagnosis, 90.6% (707/780) of the HIV/AIDS cases received the first follow up program including the CD₄⁺ T cells counts (CD₄) test service within 90 days of diagnosis, in the "Internet Plus-based HIV/AIDS care service" group presented 1.19 times (95%CI: 1.14-1.25) of the routine medical service group. The implementation of immediate treatment after HIV diagnosis, compared with the routine medical service group, the "Internet Plus" service group presented 1.71 times (95%CI: 1.03- 2.83) more treatment referrals within the 30 days of diagnosis, when the first testing CD₄ was ≤200 cells/μl. Compared with the routine medical service group, the HIV counseling and testing service group showed 1.37 times (95%CI: 1.20-1.56) more of the treatment referrals within the 30 days of HIV diagnosis, after the first testing CD₄ counts as >200 cells/μl. Conclusion Standardized care and follow-up service should be promoted as soon as the referral and treatment programs were set after the diagnosis was made, under the "Internet Plus-based AIDS Comprehensive Prevention Service System" for the MSM population, in Guangzhou.

Objective: To evaluate the effect of the "Interner Plus-based AIDS Comprehensive Prevention Service System" among MSM in Guangzhou, during 2010-2017, using a dynamic compartmental model. Methods: A dynamic compartmental model was developed to describe the HIV situation among MSM in Guangzhou. This model was parameterized on data from published literature or surveillance programs from the Guangzhou CDC. The Matlab 7.0 software was used for coding and analysis on collected data. HIV prevalence was analyzed among MSM under the status quo data and estimated the impact by the "Internet Plus" AIDS prevention services project. Results: HIV prevalence would have increased to 22.75% in 2017, and the total number of new HIV infections would have been 11 038, from 2010 to 2017, using the data status quo. Under the Guangzhou "Internet Plus" AIDS prevention services project, the prevalence of HIV among MSM from 2010 to 2017 was estimated to be 8.44%, 9.68%, 10.65%, 11.34%, 11.73%, 11.83%, 11.71% and 11.43% in Guangzhou, which were similar to the surveillance data. The total number of new infections in the past 8 years under the "Internet Plus" scenario was estimated to be 4 009. The "Internet Plus" program would have prevented 7 029 (63.68%) new infections during 2010-2017 as compared to the number, status quo. Conclusions The fitting result of dynamic compartmental model seemed more reasonable, which was applicable to predict HIV epidemic among MSM in Guangzhou, suggesting that the increase of HIV prevalence had been curbed since the "Internet Plus" project which was launched in 2010, and the "Interner Plus-based AIDS Comprehensive Prevention Service System" had achieved the purpose as planned, epidemiologically.

Objective To evaluate the correlation between cerebral blood flow perfusion and memory impairment in patients with severe stenosis of vertebral basilar artery (VBA).Methods 62 cases of patients with VBA stenosis diagnosed by digital subtraction angiography(DSA) in Beijing Tiantan Hospital from September 2016 to March 2017 were enrolled.Mental State Examination (MMSE),Clinical Memory Scale (CMS) test and CT perfusion(CTP) was performed.All patients were divided into memory normal group(n=24,including 1 excellent case,6 above normal cases,and 14 normal cases) and memory impairment group(n =38,including 18 below normal cases,12 periphery cases,8 impaired cases) according to CMS.The ratios of side-to-side period were compared between bilateral mesial temporal lobe and anterior circulation area.The relative time to peak (rTTP),relative mean transit time(rMTY),relative cerebral blood flow(rCBF) and relative cerebral blood volume (rCBV) were calculate.Results The incidence of CTP decompensation in the medial temporal lobe was higher than that in the patients with memory impairment(P＜0.05).The difference of rTTP and rMTT value between the two groups in the bilateral medial temporal lobes was statistically significant (rTFP:(1.131 ±0.037),(1.437±0.139),t=10.520,P＜ 0.05);rMTT:(1.081 ±0.059),(1.281 ±0.174),t=5.423,P＜0.05).Conclusion The patients with VBA severe stenosis are more likely to get memory impairment due to cerebral hypoperfusion.

Objective To analyse the CT,MRI features of pleomorphic xanthoastrocytoma and improve the diagnosis.Methods Imaging feature of pleomorphic xanthoastrocytoma of 26 cases confirmed by surgery and pathology were analyzed retrospectively.Distribution,size,shape,signal,dense,peritumor edema and invasion of adjacent structures of lesion were summarized.Results The locations of lesions included:temporosphenoid lobe (19 cases),frontal lobe (2 cases),the lateral and three ventricles in 1 case,occipital lobe (1 case),medulla oblongata (1 case),and cervical cord (1 case).The tumor size:maximum:82 mm × 40 mm × 70 mm,minimum:16 mm × 13 mm × 14 mm.Solid lesions (3 cases),solid lesions with necrosis (7 cases),solid and cystic lesions (16 cases),lesion with calcification (4 cases).The solid lesions of the tumors showed equal signal intensity or slightly low signal intensity on T1WI,and equal signal intensity or slightly high signal intensity on T2WI.The equidensite and high density on CT,peritumor edema degree:mild (2 cases),moderate (5 cases),severe (1 case).Conclusion The characteristic imaging features can help in the understanding and diagnosis of pleomorphic xanthoastrocytoma.