Objective To predict the constitutive parameters of a superelastic model of plantar soft tissues based on random forest(RF)and backpropagation(BP)neural network algorithms to improve the efficiency and accuracy of the method for obtaining constitutive parameters.Methods First,a finite element model for a spherical indentation experiment of plantar soft tissues was established,and the spherical indentation experiment process was simulated to obtain a dataset of nonlinear displacement and indentation force,divided into training and testing sets.The established RF and BP neural network(BPNN)models were trained separately.The constitutive parameters of plantar soft tissues were predicted using experimental data.Finally,the mean square error(MSE)and coefficient of determination(R2)were introduced to evaluate the accuracy of the model prediction,and the effectiveness of the model was verified by comparison with the experimental curves.Results Combining the RF and BPNN models with finite element simulation was an effective and accurate method for determining the superelastic constitutive parameters of plantar soft tissues.After training,the MSE of the RF model reached 1.370 2×10-3,and R2 was 0.982 9,whereas the MSE of the BPNN model reached 4.858 1×10-5,and R2 was 0.999 3.The inverse-determined constitutive parameters of the plantar soft tissues suitable for simulation were obtained.The calculated response curves for the two predicted sets of constitutive parameters were in good agreement with the experimental curves.Conclusions The prediction accuracy for the superelastic constitutive parameters of plantar soft tissues based on an artificial intelligence algorithm model is high,and the relevant research results can be applied to study other mechanical properties of plantar soft tissues.This study provides a new method for obtaining the constitutive parameters of plantar soft tissues and helps to quickly diagnose clinical problems,such as plantar soft tissue lesions.

Objective:To classify the etiology of secondary hemophagocytic syndrome (sHLH) and explore its clinical, laboratory and therapeutic characteristics in order to deepen the understanding of the disease.Method:A retrospective observational study was conducted on sHLH patients who were treated at Peking University People's Hospital from January 2016 to December 2021. Patients under the age of 18 and those with missing clinical data were excluded. The distribution of departments visited and etiologies of sHLH were analyzed. Baseline data, clinical characteristics, complications, laboratory data, treatment, and in-hospital outcomes of sHLH were collected. The sHLH patients were then divided into 3 groups including malignancy group, macrophage activation syndrome (MAS) group and other etiologies (mainly infection) group. Intergroup comparisons were performed using chi-square tests, analysis of variance, Mann-Whitney tests, and other statistical methods.Results:A total 169 patients were enrolled, among these patients, 27.8% were malignancy-related HLH, 47.9% were MAS, and 24.3% were other etiologies related HLH. Statistical analysis revealed that the clinical characteristics of other etiological group was highly consistent with the malignancy group, including more and severer peripheral blood cell reduction, higher sCD25 levels, more Epstein-Barr virus infection, and the prognosis was similar, both were with more than 50% in-hospital mortality. And the incidence of hemophagocytosis was highest in other etiological groups (65.9%). In contrast, MAS group was with an obviously lower mortality of 17.3% ( P<0.05). Meanwhile, treatments including methylprednisolone pulse, cyclosporine A and interleukin-2 were used frequently in MAS group. Conclusion:Malignancy related HLH and other etiologies related HLH exhibit more similar clinical characteristics and prognosis, while the MAS group, has a milder overall condition and better prognosis.

【Objective:】 To explore the network structure characteristics and core items of meaning in life and coping styles among college students, and provide a basis for understanding their relationships and related interventions. 【Methods:】 A survey was conducted among college students using the Simplified Coping Style Questionnaire and Meaning in Life Questionnaire . The network analysis method was used to construct a network of college students’ meaning in life and coping styles, and R software was used for statistical analysis and visualization. 【Results:】 In the network of college students’ meaning in life and coping styles, "believing that time will change the status quo, and the only thing to do is to wait" and "trying to forget the whole thing" had the closest connection. "Learning from others to handle similar difficult situations" had the highest expected impact. "Seeking the meaning in life" and "pursuing hobbies and actively participating in cultural and sports activities" had the highest bridge expected influence. The average predictability value of all nodes was 0.775. 【Conclusions:】 Interventions aimed at "learning from others to handle similar difficult situations", "changing one’s own ideas and rediscovering what is important in life" and "changing some of the original practices or problems" may maximize the coping effect of college students. "Seeking the meaning in life" can furthest influence the coping styles, and "pursuing hobbies and actively participating in cultural and sports activities" can maximize the improvement of meaning in life.

[Abstract] Objective: To develop a new type of CD7 chimeric antigen receptor modified T cell (CD7-CAR-T) for the treatment of CD7 positive acute myeloid leukemia (AML), and to observe its killing effect on CD7 positive AML cells. Methods: The CD7-CAR lentiviral vector was constructed based on the CD7 Nanobody sequence and costimulatory domain sequence of CD28 and 4-1BB. The lentiviral particles were packaged and used to co-transfect human T cells with protein expression blocker (PEBL), so as to prepare CD7- CAR-T cells. Real time cellular analysis (RTCA) was used to monitor the cytotoxicity of CD7-CAR-T cells on CD7 overexpressed 293T cells. Flow cytometry assay was used to detect the effect of CD7-CAR-T cells on proliferation and cytokine secretion of AML cells with high, medium and low CD7 expressions (KG-1, HEL and Kasumi-1 cells, respectively). Results: CD7-CAR-T cell was successfully constructed and its surface expression of CD7 was successfully blocked. Compared with T cells, CD7-CAR-T cells could significantly inhibit the proliferation of CD7-293T cells and promote the release of TNF, Granzyme B and INF-γ; in addition, CD7-CAR-T cells also significantly promoted the apoptosis (t=147.1, P<0.01; t=23.57, P<0.01) and cytokine release (P<0.05 or P<0.01) in CD7 positive KG-1 and HEL cells, but had little effect on Kasumi-1 cells that only expressed minimal CD7 antigen (t=0.7058, P>0.05). Conclusion: CD7-CAR-T cells can specifically kill CD7-positive AML cells in vitro.

Objective To investigate the status and the influencing factors of thyroid volume of children aged 8-10 years in Hefei City.Methods In 2016,according to the requirements of "National Iodine Deficiency Disorders Surveillance Plan (the 2016 Edition)",the method of multistage stratified sampling was used in 9 counties (cities,districts) of Hefei.Five primary schools were randomly selected from each county (city,district),with one in each direction (the east,west,south,north and center),then 40 children aged 8-10 years (male ∶ female =1 ∶ 1,with similar age distribution) were randomly chosen in each primary school.The thyroid volume,height and weight were measured.In addition,a questionnaire with the items including personality,learning pressure,dietary habits,related disease history and contact history was designed and used to collect the data of the subjects.Results Totally 1 800 children aged 8-10 years were selected from 45 primary schools in 9 counties (cities,districts).The mean thyroid volume was (3.009 ± 1.197) ml.Totally 71 people were found with thyroid enlargement and the goiter rate was 3.9％,which was in the range described in the elimination iodine deficiency disorders (IDD) standard (＜ 5％).Univariate analysis showed that for children in different age groups,seafood consumption frequency,radiological examination,height,and body mass,the thyroid volumes were significantly different (P＜ 0.05);Multivariate linear regression showed that body weight and height were main factors affecting the thyroid volume of children aged 8-10 years in Hefei City,the standard partial regression coefficient are 0.288 and 0.140,respectively.Conclusions The thyroid volume of the 8-10 years old children is generally in the normal range in Hefei.Goiter rate is lower than the standard for elimination of iodine deficiency The findings have showed that not only age,but also height,body mass and other factors should be considered while evaluating the influencing factors of the thyroid volume of school-aged children.

Objective To construct the male and female rat model of fluorosis and to explore the gender difference in fluorosis. Methods A total of 48 clean-grade SD rats with the body weight of about 150 g (male∶female=1∶1) were equally divided into the control group and fluorosis model group. Rats in the fluorosis model group were fed with fluorine-containing (100 mg/kg) feedstuff. The general condition, changes in body weight and dental fluorosis of the rats were observed every three days. A batch of female and male rats were sacrificed by femoral artery bleeding on the 70th and 110th day of experiment, respectively, when all rats showed dental fluorosis. The levels of urinary fluoride and bone fluoride of the rats were measured by a fluoride ion-selective electrode. Results All the male and female rats in the control group did not show dental fluorosis during the entire experiment. The female and male rats in the fluorosis group showed dental fluorosis visible to naked eye began approximately on the 60th and 80th day, respectively, indicating that the appearance of dental fluorosis of the male rats was about 20 days later than the female rats. After 30 days or so, the male and female rats went into a rapid growth period, and there were significant differences between the body weights of the male and female rats (P＜ 0. 01). The body weight of the male and female rats in the fluorosis group was higher than that of the control group on the 110th day. With the progression of fluorosis, the levels of urinary fluoride and bone fluoride of the rats were gradually increased, and finally significantly higher than those of the control group (P＜ 0. 01). There was a positive correlation between the levels of urinary and bone fluoride and the time of fluorosis. The levels of urinary and bone fluoride of the male rats were significantly higher than those of the female rats (P＜ 0. 01), indicating that they are affected by gender. Conclusions The body weight of the rat model of fluorosis, the starting time when dental fluorosis occurs and the levels of urinary and bone fluorine are all different between male and female rats.

[Objective] The objective of this study was to evaluate the diagnostic accuracy of the 2013 edition of Breast Imaging Reporting and Data System (BI-RADS) ultrasound lexicon in diagnosing breast categories 3-5 lesions.[Methods] Using our breast ultrasound database from June 2014 to June 2016,we identified 4428 BI-RADS category 3 to 5 lesions with a known pathological diagnosis in 4 428 adult women.The positive predictive value (PPV) of each BI-RADS category was calculated based on the pathological diagnoses and compared with the reference range provided by the American College of Radiology (ACR).[Results] 4 428 lesions from 4428 patients were included in this study.The PPV of each BI-RADS category waswithin the reference range provided by the ACR in 2013.1198 (27.1％) pathological malignant/borderline results were found in the 4 428 lesions,the other 3 230 (72.9％)lesions were diagnosed with benign results.Among the malignant/borderline lesions,the rate of lymph node metastasis gradually increased as the BI-RADS categories were upgraded.Malignant lesions with a diagnosis ofinvasive ductal carcinoma or invasive lobular carcinoma showed an increasing distribution trend from category 3 to 5.[Conclusion] The 2013 editionof BI-RADS ultrasound lexiconhas good diagnostic accuracy and efficiencyin clinical practice.

Objective:To prepare nanobody-based immunotoxin BI7D12-PE38KDEL targeting EGFR and to examine its cytotoxicity against EGFR positive tumor cells.Methods:By using molecular cloning strategy,prokaryotic expression construct of pET28a-BI7D12-PE38KDEL was generated which consisted of nanobody 7D12 targeting EGFR in the form of a divalent fused with PE38KDEL,a truncated form of pseudomonas exotoxin A via a flexible peptide(G4S)4,and then transformed into E.coli BL21(DE3).Protein expression was induced by adding IPTG,purified by Ni-affinity column chromatography,and verified by Western blot.The binding capacity of the resulted immunotoxin to EGFR-positive cells A549,HT29,MCF-7 and EGFR-negative cells CEM,Jurkat were determined by flow cytometry assay,and its cytotoxicity against the target cells was examined.Briefly,tumor cells were treated with different dosage of the immunotoxin,and the killing efficacy of BI7D12-PE38KDEL on these cells were assessed by WST-1 assay after 72 hours.Results:The SDS-PAGE and Western blot results showed the recombinant immunotoxin BI7D12-PE38KDEL was successfully prepared,and majority of them was expressed in soluble form.BI7D12-PE38KDEL could selectively bind to EGFR-positive cells of A549,HT29,and MCF-7.More importantly,the immunotoxin exhibited much more significant killing effect on these EGFR positive cells compared to the negative control group of CEM and Jurkat cells(P<0.01).Conclusion:In the current study,the nanobody-based immunotoxin BI7D12-PE38KDEL targeting EGFR was successfully prepared and exhibited a superior inhibition effect for the growth of EGFR-positive cells.

In order to investigate in greater detail the two methods based on Hertz model for analyzing force-distance curve obtained by atomic force microscopy, we acquired the force-distance curves of Hela and MCF-7 cells by atomic force microscopy (AFM) indentation in this study. After the determination of contact point, Young's modulus in different indentation depth were calculated with two analysis methods of "two point" and "slope fitting". The results showed that the Young's modulus of Hela cell was higher than that of MCF-7 cell,which is in accordance with the F-actin distribution of the two types of cell. We found that the Young's modulus of the cells was decreased with increasing indentation depth and the curve trends by "slope fitting". This indicated that the "slope fitting" method could reduce the error caused by the miscalculation of contact point. The purpose of this study was to provide a guidance for researcher to choose an appropriate method for analyzing AFM indentation force-distance curve.
Actins ; Elastic Modulus ; HeLa Cells ; cytology ; Humans ; MCF-7 Cells ; cytology ; Microscopy, Atomic Force

ObjectiveTo investigate the mechanism of the expression of MHC class Ⅰ chain-related A (MICA) in carcinoma of the urinary bladder,the relationship between MICA,nuclear factor-κB ( NF-κB) and p53 expression in bladder cancer was studied.MethodsThe expression of MICA,NF-κB and p53 in a total of 75 cases of urothelial carcinoma tissues and 15 normal mucous membrane tissues of the bladder was evaluated by immunohistochemistry.ResultsThe expression rates of MICA,NF-κB and p53 protein in urothelial carcinoma were 4.08％,85.3％ and 49.3％,respectively.Up-regulation of their expression was found in urothelial carcinoma compared with normal mucous membrane tissues ( P ＜ 0.05 ).MICA expression was positively correlated with NF-κB expression( r =0.256,P =0.027),but negatively correlated with p53 expression( r =- 0.23,P =0.047 ).ConclusionsUp-regulation of MICA expression was detected in bladder cancer.MICA protein may be a new tumor-associated antigen of bladder cancer.MICA expression may be regulated by NF-κB pathway,while p53 pathway may not play a part in MICA up-expression during the urothelial malignant transformation.