Construction of SARS-CoV-2 receptor binding domain molecular probe and its application in the isolation of neutralizing antibodies / 中国热带医学

@#Abstract: Objective　To construct SARS-CoV-2 receptor binding domain molecular probe for monoclonal memory B cell sorting and obtain RBD specific neutralizing antibodies from peripheral blood mononuclear cells (PBMCs) of COVID-19 convalescents by single-cell sorting. Methods　The SARS-CoV-2 RBD sequence was downloaded from GenBank, and the Avi tag and 6-histidine tags were added at the C-terminal. After codon optimization, it was chemically synthesized, cloned into the pDRVI1.0 vector, expressed after transfection of 293F cells, and biotinylated consequently. RBD-specific B cells were sorted out with this probe1 from the PBMCs of convalescents recovered from COVID-19. After B cells were lysed, the variable regions of heavy chain and light chain were amplified, cloned into the antibody expression vector, and transfected into 293F cells to express the antibody. Then the antibody was purified from the supernatant using protein A column and SARS-CoV-2 pseudovirus was used to test their neutralizing activity. Results　RBD-Avi probe was produced and successfully biotinylated sequentially with an efficiency of 30%-50%. Western blot analysis revealed that the biotinylated probe was recognized by the antibodies purified from COVID-19 convalescent plasma. Using this probe, 7 and 16 RBD-specific memory B cells were successfully isolated from the PBMCs of two convalescent individuals, accounting for 0.24% and 0.17% of the total cell population, respectively. After amplifying the variable regions of antibody heavy and light chains from the lysed B cells, 7 and 12 pairs of antibody heavy-light chains were obtained. A total of 16 antibodies were expressed in the convalescent individuals, and most of the purified antibodies showed neutralizing activity against the pseudovirus, with IC50 values of 6 antibodies below 1 μg/mL. The IC50 values of XJ-A9 and SCF-F1 against the wild-type pseudovirus were 0.07 μg/mL and 0.35 μg/mL, respectively. Conclusion　The SARS-CoV-2 RBD molecular probe constructed in this study has good antigenicity, and the isolated antibodies present neutralizing activity against wild-type SARS-CoV-2 pseudovirus.

Enlightening from optimizing post-authorization safety monitoring system of SARS-CoV-2 vaccines in major economies worldwide / 中华预防医学杂志

Ongoing global pandemic of Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has promoted the unprecedented rapid development and large-scale rolling out of different platform-based COVID-19 vaccines worldwide. How to effectively respond to the expected scale increasing adverse events after vaccination campaign of COVID-19 vaccines is a common problem faced by the world. A lot of countries and regions around the world have arranged in advance at different levels, optimizing the original vaccine safety monitoring system from the perspectives of strengthening the foundation and capabilities, promoting internal and external cooperation, upgrading methods, as well as improving transparency and public communication, which has ensured the good and efficient operation of the system and can provide reference for the construction of relevant fields in China.

Clinical Characteristics and Risk Factors of Invasive Fungal Infections in Acute Leukemia Patients in Tropical Regions / 中国实验血液学杂志

OBJECTIVE@#To analyze the clinical characteristics and risk factors of invasive fungal infection (IFI) occurenced in patients with acute leukemia (AL) during treatment in tropical regions.@*METHODS@#The clinical data of 68 AL patients admitted to the Hainan Hospital of PLA General Hospital from April 2012 to April 2019 was retrospectively analyzed. Logistic regression analysis was used to analyze the factors affecting the occurrence of IFI in AL patients.@*RESULTS@#Among the 68 patients, 44 were acute myeloid leukemia, 24 were acute lymphoblastic leukemia, 39 were male, 29 were female and the median age was 41(13-75) years old. The 68 patients received 242 times of chemotherapy or hematopoietic stem cell transplantation(HSCT), including 73 times of initial chemotherapy or inducting chemotherapy after recurrence, 14 times of HSCT, 155 times of consolidating chemotherapy. Patients received 152 times of anti-fungal prophylaxis, including 77 times of primary anti-fungal prophylaxis and 75 times of secondary anti-fungal prophylaxis. Finally, the incidence of IFI was 31 times, including 24 times of probable diagnosis, 7 times of proven diagnosis, and the total incidence of IFI was 12.8%(31/242), the incidence of IFI in inducting chemotherapy was 24.66%(18/73), the incidence of IFI in HSCT patients was 28.57% (4/14), the incidence of IFI in consolidating chemotherapy was 5.80% (9/155). Multivariate analysis showed that inducting chemotherapy or HSCT, the time of agranulocytosis ≥7 days, risk stratification of high risk were the independent risk factors for IFI in AL patients during treatment in tropical regions.@*CONCLUSION@#The incidence of IFI in patients with AL in the tropics regions is significantly higher than that in other regions at homeland and abroad. Anti-fungal prophylaxis should be given to the patients with AL who have the high risk factors of inducting chemotherapy or HSCT, time of agranulocytosis ≥7 days and risk stratification of high risk.

Associated factors for HIV stigma among the patients on antiretroviral therapy in Wenshan Prefecture / 预防医学

Objective@#To learn HIV related stigma and its associated factors among the patients on antiretroviral therapy ( ART ) in Wenshan Prefecture, Yunnan Province, so as to provide evidence for eliminating HIV discrimination.@*Methods@#A total of 419 subjects were recruited by convenience sampling from three ART clinics in Wenshan City and Maguan County between October 2017 and January 2018. HIV/AIDS Related Stigma and Discrimination Scale developed by Li Xianhong et al was employed. The multivariate linear regression model were used to explore the influencing factors for HIV stigma. @*Results@#The median scores of disclosure concern, public rejection, family stigma, internalized stigma, health service providers＇ stigma were 24.00, 6.00, 10.00, 20.00, 2.00, respectively, and the overall was 68.00. The multivariate linear regression analysis showed that female patients ( standardized β=0.135 ) , patients with opportunistic infection ( standardized β=0.120 ), patients had no HIV infected family member ( standardized β=-0.128 ) , patients without family support ( standardized β=-0.175 ) , patients received gift from ART clinics ( standardized β=0.124 ) , patients scored lower in ART knowledge ( standardized β=-0.117 ) were likely to scored higher in HIV stigma. @*Conclusions@#The stigma on disclosure concern and internalized stigma dimensions are grievous among ART patients in Wenshan Prefecture. Gender, opportunistic infection, HIV infection in family, family support, receiving incentive gifts from clinics and awareness of ART are associated with HIV stigma.

Influencing factors of depressive symptoms in Zhejiang adolescents / 预防医学

Objective@#To investigate the prevalence and influencing factors of adolescent depression symptoms in Zhejiang, so as to provide reference for improving their mental health. @*Methods@#The middle school and university students in 11 cities of Zhejiang Province were selected by stratified cluster random sampling method. The depression symptoms of the adolescents were assessed by Center for Epidemiological Survey-Depression Scale ( CES-D ) and the influencing factors were analyzed by multivariate logistic regression model.@*Results@# A total of 25 855 students were investigated, and 25 614 ( 99.07% ) valid questionnaires were collected. The detection rate of depressive symptoms was 26.86%(6 879 cases). The detection rate of depressive symptoms in girls was 29.75%, which was higher than 24.12% in boys ( P<0.05). The detection rate of depressive symptoms in high school students was 31.74%, the highest compared with other grades. The multivariate regression analysis showed that female students ( OR=1.690, 95%CI: 1.592-1.794 ), resident students ( OR=1.071, 95%CI: 1.010-1.137 ) , internet addiction ( OR=2.948, 95%CI: 2.527-3.439 ) , attempt smoking ( OR=1.516, 95%CI: 1.359-1.690 ), drinking ( OR=1.624, 95%CI: 1.525-1.729 ), bullied in the past 30 days ( OR=3.143, 95%CI: 2.938-3.363 and having serious injuries within a year ( OR=1.369, 95%CI: 1.263-1.543 ) were associated with adolescents who had depressive symptoms.@*Conclusions@#The detection rate of depressive symptoms is relative 26.86% among adolescents of Zhejiang Province. The students who are female, live on campus, have internet addiction, have been bullied or seriously injured, smoke and drink are more likely to have depressive symptoms.

A cross-sectional study of overweight and obesity among 7-22 year-old students in Zhejiang Province / 预防医学

Objective @#To understand the prevalence of overweight and obesity, and the influencing factors among students aged 7-22 years in Zhejiang Province. @*Methods @#Stratified random cluster sampling was used to randomly select students aged 7-22 years in 11 prefectures of Zhejiang Province in 2019. Height and weight were measured. The general information, dietary habits and living habits of students were collected using the Student Health Status and Influencing Factors Questionnaire. The multivariate logistic regression model was used to analyze the influencing factors of overweight and obesity. @*Results @#A total of 33 800 respondents were included, 7 685 (22.74%) were overweight/obese, 4 729 ( 13.99% ) were overweight, and 2 956 ( 8.75% ) were obese. The multivariate logistic regression analysis suggested that boys ( OR=2.059, 95%CI：1.949-2.175), not living on campus( OR=1.306, 95%CI: 1.214-1.405), history of alcohol consumption ( OR=1.158, 95%CI：1.083-1.238 ), average daily consumption of sugar-sweetened beverages in the past week ( less than once, OR=1.214, 95%CI: 1.103-1.336; once and more, OR=1.431, 95%CI: 1.259-1.626 ), average daily consumption of fries in the past week ( less than once, OR=1.171, 95%CI: 1.065-1.288; once and more, OR=1.266, 95%CI: 1.102-1.454 ), and average daily consumption of sweets in the past week (less than once, OR=0.727, 95%CI: 0.658-0.802; once and more, OR=0.504, 95%CI: 0.444-0.572) were associated with overweight and obesity in students. @*Conclusion @#The prevalence rates of overweight and obesity among students aged 7-22 years in Zhejiang Province are 13.99% and 8.75%, respectively, which are associated with boys, not living on campus, and consumption of sugar-sweetened beverages, fries, sweets and alcohol.

Association of dietary niacin intake with metabolic syndromeamong adults in Zhejiang Province / 预防医学

Objective @#To explore the association of dietary niacin intake and metabolic syndrome ( MS ) and its components among adults in Zhejiang Province, so as to provide the reference for dietary intervention of MS.@*Methods@#Using the multi-stage cluster random sampling method, the permanent residents aged 18 years and above were selected and investigated by a questionnaire developed by China Center for Disease Control and Prevention. Their waist circumference, blood pressure, glucose and lipid were measured. The daily dietary niacin intake of each person were calculated by "24-hour dietary review for 3 consecutive days", and divided into Q1, Q2, Q3 and Q4 groups according to quartiles. The multivariate logistic regression model was used to analyze the association of niacin intake with the risks of MS and its components. @*Results@#Among 2 438 participants, 871 cases with MS were detected, with a detection rate of 35.73%. The multivariate logistic regression analysis showed that compared with niacin intake Q1 group, Q2 ( OR=0.741, 95%CI: 0.561-0.978 ) and Q4 group ( OR=0.679, 95%CI: 0.487-0.947 ) had a lower risk of MS, Q2 ( OR=0.688, 95%CI: 0.516-0.919 ) and Q4 group ( OR=0.678, 95%CI: 0.479-0.960 ) had a lower risk of abdominal obesity, Q4 group ( OR=0.721, 95%CI: 0.536-0.969 ) had a lower risk of hyperglycemia. Further stratificating by gender, compared with niacin intake Q1 group, Q2 ( OR=0.664, 95%CI: 0.453-0.972 ) and Q3 group ( OR=0.646, 95%CI: 0.432-0.965 ) in women had a lower risk of MS, Q2 (OR=0.667, 95%CI: 0.460-0.967) and Q3 group ( OR=0.607, 95%CI: 0.408-0.902 ) had a lower risk of abdominal obesity; Q2 group ( OR=1.836, 95%CI: 1.202-2.805 ) in men had a higher risk of low high-density lipoprotein cholesterol.@*Conclusion@#Niacin intake is associated with an increased risk of MS, abdominal obesity and hyperglycemia.

Stability evaluation of different internal fixation methods for zygomaticomaxillary complex fractures by finite element biomechanical analysis / 中华实验眼科杂志

Objective:To analyze the stability of different internal fixation methods for zygomaticomaxillary complex fracture using finite element biomechanical analysis and to provide a quantitative basis for the option of optimal internal fixation methods.Methods:One patient with zygomaticomaxillary complex ZMC fracture (Zingg B type) was enrolled from the Second Hospital of Dalian Medical University in October 2016.The zygomaticofrontal suture and the inferior orbital rim were fixed during the surgery, and the postoperative function was well recovered with no mouth opening restriction, diplopia or implant displacement, and had a symmetrical facial appearance.The preoperative orbital CT images were collected.The normal craniofacial bones finite element model (FEM/intact) was reconstructed through Mimics, Geomagic, Solidworks and Abaqus softwares based on the non-fractured side and verified.Based on the verified model, the segmentation and assembling was performed according to the fracture location, and the internal fixation models were established according to the methods of surgery, including fixed zygomaticofrontal suture model (FEM/ZFS), fixed inferior orbital rim model(FEM/IOR), fixed zygomaticofrontal suture and inferior orbital rim model (FEM/ZFS+ IOR), fixed ZFS and IOR and zygomaticomaxillary suture model (FEM/ZFS+ IOR+ ZMS). The masseter muscle strength was applied to the model.The stress and displacement were analyzed and the rotation angle of zygoma was calculated to compare the stability of different operative methods.The postoperative model (FEM/post) was established according to the actual operative method and was compared with FEM/ZFS+ IOR.This study protocol was approved by the Ethic Committee of The Second Hospital of Dalian Medical University (2020-33), and written informed consent was obtained from the subject before entering the study.Results:The established FEM/intact had a realistic appearance and good geometric similarity, and the validity and accuracy of model was verified.In the FEM/ZFS+ IOR and FEM/ZFS+ IOR+ ZMS, the maximal stress of the titanium plate was 396 MPa and 426 MPa, respectively, which was lower than the yield strength 483 MPa of pure titanium, and the maximal displacement of the fracture line was 0.10 mm and 0.06 mm, respectively, which was both≤0.1 mm, and the rotation angle of zygoma was both<2°.In the FEM/ZFS and FEM/IOR, the maximal stress of the titanium plate was 730 MPa and 501 MPa, respectively, which was higher than the yield strength of pure titanium; the maximal displacement of fracture line was 0.27 mm and 0.15 mm, respectively, which was >0.1 mm, and the rotation angle of zygoma was <2°.The results of FEM/post were consistent with those of FEM/ZFS+ IOR.Conclusions:The finite element analysis can perform digital analysis and evaluation of the stability of different internal fixation methods before surgery, which is available for the selecting of the optimal fixation methods.Finite element analysis can provide an objective quantitative basis for the precise treatment of zygomaticomaxillary complex fractures.

Advances in Clinical Application of Numerical Study of Ear and Upper Airway / 医用生物力学

Ear and upper airway are portal organs of human body. Because of their fine and narrow structure, the non-invasive research and the effect of clinical diagnosis and treatment in traditional medicine are always unsatisfactory. With the development of computer technology, numerical simulation has become an effective means of auxiliary research. Numerical simulation can reproduce or evaluate the diagnosis and treatment of ear and upper airway diseases, and it is a powerful means to promote the development of basic medicine and technology of clinical diagnosis and treatment. The application of numerical simulation in relationship between the structure and function of ear and upper airway, the influence of diseases on function, the evaluation of clinical diagnosis and treatment technology， as well as the design of related medical devices were reviewed. The clinical application of numerical research in ear and upper airway was prospected, so as to provide references for the future clinical diagnosis and treatment of ear and upper airway.

Association between Chinese Medicine Therapy and Survival Outcomes in Postoperative Patients with NSCLC: A Multicenter, Prospective, Cohort Study / 中国结合医学杂志

OBJECTIVE@#To evaluate the association between Chinese medicine (CM) therapy and disease-free survival (DFS) outcomes in postoperative patients with non-small cell lung cancer (NSCLC).@*METHODS@#This multiple-center prospective cohort study was conducted in 13 medical centers in China. Patients with stage I, II, or IIIA NSCLC who had undergone radical resection and received conventional postoperative treatment according to the National Comprehensive Cancer Network (NCCN) guidelines were recruited. The recruited patients were divided into a CM treatment group and a control group according to their wishes. Patients in the CM treatment group received continuous CM therapy for more than 6 months or until disease progression. Patients in the control group received CM therapy for less than 1 month. Follow-up was conducted over 3 years. The primary outcome was DFS, with recurrence/metastasis rates as a secondary outcome.@*RESULTS@#Between May 2013 and August 2016, 503 patients were enrolled into the cohort; 266 were classified in the CM treatment group and 237 in the control group. Adjusting for covariates, high exposure to CM was associated with better DFS [hazard ratio (HR) = 0.417, 95% confidential interval (CI): 0.307-0.567)]. A longer duration of CM therapy (6-12 months, 12-18 months, >24 months) was associated with lower recurrence and metastasis rates (HR = 0.225, 0.119 and 0.083, respectively). In a subgroup exploratory analysis, CM therapy was also a protective factor of cancer recurrence and metastasis in both stage I-IIIA (HR=0.50, 95% CI: 0.37-0.67) and stage IIIA NSCLC postoperative patients (HR = 0.48, 95% CI: 0.33-0.71), DFS was even longer among CM treatment group patients.@*CONCLUSIONS@#Longer duration of CM therapy could be considered a protective factor of cancer recurrence and metastasis. CM treatment is associated with improving survival outcomes of postoperative NSCLC patients in China. (Registration No. ChiCTR-OOC-14005398).

Clinical diagnosis and treatment for iliotibial band syndrome / 中国骨伤

As an usually occurs in athletes, iliotibial band syndrome is payed more attention for people, the disease is diagnosed mainly by clinical symptoms, physical examination and MRI, but there is no uniform diagnostic criteria. The pathogenesis of iliotibial band syndrome is considered to be related to pressure and friction factors. As for the treatment, manipulation, muscle exercise, mainly drugs and physical therapy and so on both at home and abroad are recognized to use to achieve desired effect. For conservative failure, refractory iliotibial band syndrome patients, arthroscopy, or release of iliotibial band syndrome surgery are performed. While conservative local drug injection combined with muscle exercise could play a role in pain management besides, arthroscopic as operation method is more advanced, and applicable to all types of patients without absolute contraindication, so it is helpful for patients with early activity. At present, there is still a great deal of controversy about its pathogenesis, and there is no obvious limit for the specific indications of its various therapies in clinic, so it needs further specification.

The mechanism of sensing postural changes in human ears by numerical simulation / 医用生物力学

Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals.Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear.Results Compared with the complicated node displacement distribution,the volumetric strain distribution of cupula was regular.Specifically,each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity.The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula),the anterior semicircular canal cupula (AC cupula),and the posterior semicircular canal cupula (PC cupula),was approximately 1.00∶0.80 ∶ 1.72,which kept constant.In addition,the volumetric strain of HC cupula was in phase with that of AC cupula,but showing 14.4° out of phase with the angular velocity,and 180° out of phase with that of PC cupula.Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal,and the amplitude,frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity,respectively.These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex,and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.

The mechanism of sensing postural changes in human ears by numerical simulation / 医用生物力学

Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals.Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear.Results Compared with the complicated node displacement distribution,the volumetric strain distribution of cupula was regular.Specifically,each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity.The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula),the anterior semicircular canal cupula (AC cupula),and the posterior semicircular canal cupula (PC cupula),was approximately 1.00∶0.80 ∶ 1.72,which kept constant.In addition,the volumetric strain of HC cupula was in phase with that of AC cupula,but showing 14.4° out of phase with the angular velocity,and 180° out of phase with that of PC cupula.Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal,and the amplitude,frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity,respectively.These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex,and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.

The mechanism of sensing postural changes in human ears by numerical simulation / 医用生物力学

Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals. Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear. Results Compared with the complicated node displacement distribution, the volumetric strain distribution of cupula was regular. Specifically, each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity. The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula), the anterior semicircular canal cupula (AC cupula), and the posterior semicircular canal cupula (PC cupula), was approximately 1.00︰0.80︰1.72, which kept constant. In addition, the volumetric strain of HC cupula was in phase with that of AC cupula, but showing 14.4° out of phase with the angular velocity, and 180° out of phase with that of PC cupula. Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal, and the amplitude, frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity, respectively. These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex, and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.

Comprehensive treatment with Chinese medicine in patients with advanced non-small cell lung cancer: A multicenter, prospective, cohort study / 中国结合医学杂志

<p><b>OBJECTIVE</b>To determine whether additional Chinese medicine (CM) could prolong survival and improve the quality of life (QOL) in patients with advanced non-small cell lung cancer (NSCLC) compared with Western medicine (WM) alone.</p><p><b>METHODS</b>This was a multicenter, prospective cohort study. A total of 474 hospitalized patients with stage III-IV NSCLC were recruited and divided into 2 groups. Patients in the WM group received radiotherapy, chemotherapy, and optimal supportive therapy according to the National Comprehensive Cancer Network (NCCN) guidelines. In the integrative medicine (IM) group, individualized CM (Chinese patent medicines and injections) and WM were administered. The primary end point was overall survival, and the secondary end points were time to disease progression, adverse events, and QOL. Follow-up clinical examinations and chest radiography were performed every 2 months.</p><p><b>RESULTS</b>The median survival was 16.60 months in the IM group and 13.13 months in the WM group (P<0.01). The incidences of loss of appetite, nausea, and vomiting in the IM group were significantly lower than those in the WM group (P<0.05). The QOL based on Functional Assessment of Cancer Therapy-Lung in the IM group was markedly higher than that in the WM group at the fourth course (P<0.05).</p><p><b>CONCLUSIONS</b>Additional CM may prolong survival and improve the QOL patients with NSCLC. The adverse effects of radio- and chemotherapy may be attenuated as CM is used in combination with conventional treatments.</p>

The mechanism of sensing postural changes in human ears by numerical simulation / 医用生物力学

Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals.Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear.Results Compared with the complicated node displacement distribution,the volumetric strain distribution of cupula was regular.Specifically,each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity.The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula),the anterior semicircular canal cupula (AC cupula),and the posterior semicircular canal cupula (PC cupula),was approximately 1.00∶0.80 ∶ 1.72,which kept constant.In addition,the volumetric strain of HC cupula was in phase with that of AC cupula,but showing 14.4° out of phase with the angular velocity,and 180° out of phase with that of PC cupula.Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal,and the amplitude,frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity,respectively.These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex,and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.

Discrimination between Metastatic and Non-metastatic Regional Lymph Nodes in Rectal Cancer Using Quantitative Dynamic Contrast-enhanced Parameters / 中山大学学报(医学科学版)

[Objective]To investigate the diagnostic value of quantitative perfusion parameters of dynamic contrast-enhanced im?aging for discriminating metastatic from non-metastatic regional lymph nodes in rectal cancer.[Methods]122 patients of our depart?ment were collected from 2015.01 to 2016.08, and 203 lymph nodes, including metastatic lymph nodes (MLNs, n=95) and non-meta?static lymph nodes (NMLNs, n=108), were analyzed. The short-axis diameter (S), long-axis diameter (L), short-to long-axis diameter ratio (S/L), volume transfer constant (Ktrans), rate constant (Kep) and extravascular extracellular space (EES) fractional volume (Ve) were compared between two groups respectively. Then using S=5 mm as a cutoff value, these parameters were compared between subgroups. Receive operating characteristic curve (ROC) was used to analyze the diagnostic efficiency and find the optimal cutoff values.[Re?sults]The metastatic group exhibited higher S and L, but lower S/L, Ktrans and Kep than the non-metastatic group (P<0.01). However, the Ve did not differ significantly between two groups (P=0.308). Optimal cutoff values [area under the curve (AUC), sensitivity, speci?ficity] of Ktrans for discriminate metastatic lymph nodes from non-metastatic were 0.088 min-1 (0.69, 58.3%, 78.9%). When S>/=5 mm, subgroup analysis revealed that Ktrans and Kep of MLNs were significant higher than those of NMLNs (P<0.001), but Ve was lower (P=0.039). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.088 min-1 (0.675, 57.1%, 77.9%). However, when S<5 mm, MLNs showed lower Ktrans than NMLNs (P=0.001), but there were no significantly statistic differences of Kep and Ve between these two groups (P>0.1). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.087 min-1 (0.732, 60.5%, 81.5%).[Conclusion]Ktrans can be used to discriminate regional MLNs from NMLNs in rectal cancer, especially when the short-axis diameter is less than 5 millimeters.

Numerical analysis on deposition of particulate matters in respiratory tract / 医用生物力学

Objective To study the regular pattern of inhalational particulate matter deposition in respiratory tract and its influencing factors during breathing by numerical simulation method. Methods Three-dimensional finite element model of normal human respiratory tract was established to simulate the airflow distributions in respiratory tract during inspiration. The particles were released at the entrance of nose or mouth to simulate the deposition process of suspended particles by inhaled airflow in respiratory tract. Different parameters such as particle diameter, particle density and flow rate of air volume were used for comparative analysis to investigate their functions as influencing factors when particle deposition happened in respiratory tract. Results The particles were mainly deposited in nasal threshold, nasal middle airway, nasopharynx, and bronchial inner wall of respiratory tract. The particle deposition rate increased with the parameters of particle diameter, particle density and air volume flow rate increasing. The influence of different parameters on the deposition rate was not the same. Conclusions The particle is mainly deposited at the site with complex geometry or at the position where path direction changes violently. Particle diameter, density and breathing airflow rate will affect the deposition rate in respiratory tract. These research findings will provide numerical references for the clinical assessment on risk of respiratory diseases caused by air pollution.

Numerical simulation of intranasal airlfow ifeld / 中国耳鼻咽喉头颈外科

[ABSTRACT]OBJECTIVETo explore the basic characters of the airflow-field in Chinese people's nasal cavity by computational fluid dynamics.METHODSThe three-dimensional, finite-element mesh were developed from Spiral CT imaging scans of nose of the 40 healthy Chinese people. Given the following spatial boundaries of the flow field: no-slip condition was imposed at the surface of the nasal airway walls; a standard atmosphere pressure condition was established at the inlet; a velocity vector was specified at the outlet (nasopharynx), which was obtained under the condition of aspiratory flow rate (12 L/min), the full Navier-Stokes and continuity equations were solved to obtain the airflow pattern.RESULTS1. The airflow passed mainly through left or right side of the nasal airway in the whole 40 cases (left 33, right 7),and the volume of air through the main-side is (320±28) ml while non-main-side (180±45) ml. 2. Airflow velocity: airflow of anterior nostrils, internal nostrils, the middle and inferior parts of the total meatus in the main-side were (5.01±2.12) m/s, (7.00±1.75) m/s, (5.08±1.55) m/s, (4.12±1.40) m/s respectively, and those in non-main-side were (2.01±0.94) m/s, (2.40±0.34) m/s, (1.99±1.0) m/s, (2.01±0.65) m/s respectively, which differences between the both sides were of statistical significance (allP0.05); 3. The airflow form appeared to be linear in the middle and inferior parts of the nasal cavity. 4. Velocity in maxillary sinus cavity was almost 0 m/s.CONCLUSIONThe airflow passes mainly through the middle and inferior parts of the meatus with higher velocity in laminar form and airflow of middle meatus, inferior meatus and olfactory cleft are low and the velocity were slow. Besides, airflow in maxillary sinus cavity diffuses free mainly.