Breast cancer is the most common cancer in women and one of the deadliest cancers worldwide.According to the distribution of tumor tissue,breast cancer can be divided into invasive and non-invasive forms.The cancer cells in invasive breast cancer pass through the breast and through the immune system or systemic circulation to different parts of the body,forming metastatic breast cancer.Drug resistance and distant metastasis are the main causes of death from breast cancer.Research on breast cancer has attracted extensive attention from researchers.In vitro construction of tumor models by tissue engineering methods is a common tool for studying cancer mechanisms and anticancer drug screening.The tumor microenvironment consists of cancer cells and various types of stromal cells,including fibroblasts,endothelial cells,mesenchymal cells,and immune cells embedded in the extracellular matrix.The extracellular matrix contains fibrin proteins(such as types Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅵ,and Ⅹcollagen and elastin)and glycoproteins(such as proteoglycan,laminin,and fibronectin),which are involved in cell signaling and binding of growth factors.The current traditional two-dimensional(2D)tumor models are limited by the growth environment and often cannot accurately reproduce the heterogeneity and complexity of tumor tissues in vivo.Therefore,in recent years,research on three-dimensional(3D)tumor models has gradually increased,especially 3D bioprinting models with high precision and repeatability.Compared with a 2D model,the 3D environment can better simulate the complex extracellular matrix components and structures in the tumor microenvironment.Three-dimensional models are often used as a bridge between 2D cellular level experiments and animal experiments.Acellular matrix,gelatin,sodium alginate,and other natural materials are widely used in the construction of tumor models because of their excellent biocompatibility and non-immune rejection.Here,we review various natural scaffold materials and construction methods involved in 3D tissue-engineered tumor models,as a reference for research in the field of breast cancer.

{L-End}Objective To investigate the current status of long working hours of food-delivery workers from food-delivery platform, and analyze its impact on their health such as occupational stress, depressive symptoms, insomnia symptoms, fatigue accumulation, and life satisfaction. {L-End}Methods A total of 2 145 food-delivery workers from two food-delivery platforms in Guangzhou City were selected as the research subjects using convenience sampling method. The occupational stress, depressive symptoms, insomnia symptoms, fatigue accumulation, and life satisfaction were investigated using the Core Occupational Stress Scale, Patient Health Questionnaire-9 items, Self-sleep Management Questionnaire, Self-diagnosis Questionnaire of Fatigue Accumulation of Workers, and World Health Organization Five-item Well Being Index. {L-End}Results The median and the 25th and 75th percentiles of weekly working hours were 63 (49,77) hours. And 92.2% (1 978/2 145) of workers, who worked more than 40 hours per week, were long working hours workers. While 70.1% (1 504/2 145) workers, who worked 55 hours or more per week, were ultra-long working hours workers. The detection rate of occupational stress, depressive symptoms, insomnia symptoms, fatigue accumulation, and low life satisfaction was 30.1%, 27.5%, 34.7%, 40.8%, and 75.1%, respectively. The longer the weekly working hours of the research subjects, the higher the detection rate of occupational stress and fatigue accumulation (all P<0.01). The results of multivariate logistic regression analysis showed that ultra-long working hours (weekly working hours ≥55 hours) was the influencing factor of occupational stress and fatigue accumulation after excluding the influence of confounding factors among workers (all P<0.05). {L-End}Conclusion The food-delivery workers of food-delivery platforms generally work long hours. Ultra-long working hours is a risk factor for occupational stress and fatigue accumulation among these workers.

Objective:To explore the influencing and prognosis factors of emphysematous urinary tract infection (EUTI).Methods:The baseline clinical data of the patients admitted to Shandong University Qilu Hospital (Qingdao) from December 2013 to June 2020 and diagnosed with EUTI were analyzed retrospectively. The patients with non-EUTI (NEUTI) during the same period were selected as the control group. The baseline characteristics between the two groups were compared. Logistic regression analysis method was used to analyze the influencing factors of EUTI.Results:(1) 24 EUTI patients and 53 NEUTI patients were included in the present study. Compared with the NEUTI group, the hemoglobin level was lower ( t=-5.245, P<0.001) and the levels of blood urine nitrogen ( Z=-4.361, P<0.001), serum creatinine (Scr, Z=-4.543, P<0.001), blood glucose ( Z=-2.608, P=0.009), and triacylglycerol ( Z=-2.408, P=0.016) were higher in the EUTI group. The proportions of diabetes mellitus ( χ2=13.453, P<0.001) and chronic kidney disease ( χ2=17.936, P<0.001) in the EUTI group were higher than those in the NEUTI group. Increasing Scr was the risk factor of EUTI in patients with urinary tract infection ( OR=1.011, 95% CI 1.001-1.020, P=0.025). (2) Escherichia coli ( E.coli, 14 cases, 58.3%) was the most common causative organism. The other causative organisms included Klebsiella pneumoniae (2 cases, 8.3%), Enterococcus faecium (1 case, 4.2%), Pantoea (1 case, 4.2%), and mixed bacteria of E.coli and Enterococcus faecium (1 case, 4.2%). Ten cases of E.coli were extended-spectrum β-lactamases (ESBL)-positive. (3) Of the 24 patients with EUTI, 4 patients had adverse outcomes. The length of stay ( Z=-2.457, P=0.014), blood urea nitrogen ( t=2.432, P=0.024), shock ( P=0.002), autoimmune disease ( P=0.022), and white blood cell count ( Z=-2.091, P=0.036) were statistically different between good prognosis group ( n=20) and poor prognosis group ( n=4). However, logistic regression analysis results showed that neither was the influencing factor of poor prognosis of EUTI. Conclusions:The elevated Scr level is the independent influencing factor of EUTI among urinary infection patients. E.coli is the most common pathogenic bacteria, and ESBL-positive bacteria are common.

Group A Streptococcus (GAS) is a very important pathogen, especially for children.On a global scale, GAS is an important cause of morbidity and mortality.But the burden of disease caused by GAS is still unknown in China and also has not obtained enough attention.For this purpose, the expert consensus is comprehensively described in diagnosis, treatment and prevention of GAS diseases in children, covering related aspects of pneumology, infectiology, immunology, microbiology, cardiology, nephrology, critical care medicine and preventive medicine.Accordingly, the consensus document was intended to improve management strategies of GAS disease in Chinese children.

Objective:To evaluate the feasibility and effectiveness of parathyroid autotransplantation in subcutaneous tissue of upper abdomen after total parathyroidectomy in patients with severe secondary hyperparathyroidism (SHPT).Methods:From January 2018 to January 2020, retrospective reviews were conducted for clinical data of 29 patients with secondary hyperparathyroidism undergoing epigastric parathyroid autotransplantation after total parathyroidectomy.Clinical and biochemical characteristics were recorded.Serum levels of calcium, phosphorus, parathyroid hormone and alkaline phosphatase before and after operation were analyzed by paired sample t-test and the difference was statistically significant ( P<0.01). The follow-up period was 1, 3, 6 and 12 months post-operation and yearly after 12 months. Results:All operations were successful.The postoperative levels of calcium[(2.25±0.32) vs.(2.49±0.24) mmol/L], phosphorus[(1.72±0.65) vs. (2.09±0.75) mmol/L], alkaline phosphatase[(199.02±77.68) vs.(384.21±154.5) U/L]and parathyroid hormone (PTH)[(8.01±7.00) vs.(1 930.64±620.51) pg/ml]were significantly lower than the preoperative levels ( P<0.01). And the differences were statistically significant.And 17/18 hypertensive patients improved post-operation; postoperative improvement was not obvious for 21 anemic patients, 17 patients improved within 1 year.Among 26 cases with bone pain, 16 cases disappeared immediately postoperatively, 5 disappeared within 1 month and 5 within 3 months.Among 13 cases with skin itch, 10 cases disappeared immediately and 3 cases at 1 month post-operation.The level of PTH recovered at different follow-up timepoints with an average recovery time of (4.45±2.31) months. Conclusions:Autologous transplantation of parathyroid gland in epigastric subcutaneous tissue after parathyroidectomy is both safe and effective for secondary hyperparathyroidism.

Objective:To investigate the neural mechanism of long-term exposure to high altitudes environment on the processing stage of perceptual closure.Methods:A cross-sectional study was conducted. Thirty college students who first entered the plateau area (at an altitude of 3 658 m) and had lived in high-altitude areas for two years were selected as high altitude group (HA group), and 29 college students matched in age, gender and education level who had never been to the plateau area were selected as sea level group (SL group). The differences of basic physiological parameters were compared between the two groups.The face pairwise comparison paradigm was applied in the subjects of the two groups and the differences between the two groups were compared by event-related potentials (ERPs) technology. SPSS 22.0 software was used for statistical analysis, and the mean ± standard deviation was used for statistical description. Independent sample t test was used for comparison of physiological data between the two groups, and repeated measurement variance analysis was used for ERP data. Results:The physiological results revealed that the HA group had a higher pulse rate((86.71±10.82)/min, (75.97±11.28)/min ; t=-3.19, P=0.002) and diastolic blood pressure than the SL group ((75.93±9.19)mmHg, ( 68.59±11.42) mmHg ; t=-3.20, P=0.002). The oxygen saturation level was significantly lower than that of SL group ((90.77±2.25)%, (98.31±1.56) %) ; t=14.00, P<0.001). In the face pairwise comparison paradigm test, the main effect of P1 latency of ERP was significant.Compared with SL group, HA group showed significantly shortened latency of P1 ((105.10±15.59) ms, (128.35±14.40)ms, P<0.001). The main effect of group of N170 amplitude was significant, HA group was larger than that of SL group((-7.57±3.83) μV, ( -5.11±3.26) μV, P=0.005). The interaction effect between group and hemisphere of NCL amplitude was significant ( F(1, 57)=9.72, P=0.003). Simple effect test showed that the amplitude on the right hemisphere of SL group was significantly larger than that on the left hemisphere((0.46±1.31) μV), (1.16±1.33) μV ). The latency of P1 was significantly correlated with heart rate( r=-0.46, P<0.01), oxygen saturation level( r=0.64, P<0.01) and diastolic blood pressure( r=-0.26, P=0.049). Conclusion:After long-term exposure to high altitude, the neural response related to early visual perception is faster. More psychological resources are recruited during the face structural encoding stage. Contra-lateral compensating effect appeares in the stage of perceptual closure.

Objective:To analyze the association of pre-transplant risk factors with diabetes mellitus after renal transplantation and examine the significance of preventing the occurrence in kidney transplantation recipients.Methods:A total of 290 kidney transplantation recipients were retrospectively reviewed at our transplantation center from August 2018 to May 2020.Diabetes mellitus after renal transplantation was employed as a primary outcome index.Multivariate Logistic regression model was utilized for constructing A (without adjusting for covariates)、B(covariates include: gender, dialysis mode, type of donation)and C(covariates include: gender, dialysis mode, type of donation, calcineurin inhibitor, antiproliferative drugs, primary disease, fasting blood glucose, 1 h postprandial blood glucose, fasting C peptide, 1 h and 2 h postprandial C peptide, fasting C-peptide index, 1 h postprandial C-peptide index, albumin, triglycerides, total cholesterol)to evaluate the relationship between diabetes mellitus after transplantation and age, body mass index, 2 h postprandial blood glucose(2 h-PG), HbA1c, and 2 h postprandial C-peptide index(2 h-CPI).Results:In model A, age [odds ratio(OR)1.1, 95% confidence interval( CI)1.0~1.1], BMI(OR 1.2, 95% CI 1.0~1.3), 2 h PG(OR 1.2, 95% CI 1.1~1.4), HbA1c(OR 2.7, 95% CI 1.5~4.9), 2 h-CPI(OR 0.7, 95% CI 0.5~1.0), model B/C had similar results with A. Age, BMI, 2 h PG and HbA1c were all risk factors for diabetes mellitus after transplantation while 2 h-CPI was a protective factor.Quartile stratification was analyzed by regression model.And trend test was significant( P<0.05). Conclusions:Age, BMI, 2 h PG, HbA1c and 2 h-CPI are correlated with diabetes mellitus after kidney transplantation.

Objective To analyze the risk factors for the occurrence of post transplantation diabetes mellitus (PTDM) in renal transplant recipients, establish a prediction model for PTDM and evaluate its prediction value. Methods Clinical data of 915 renal transplant recipients were retrospectively analyzed. According to the occurrence of PTDM, all recipients were divided into the PTDM group (n=78) and non-PTDM group (n=837). The main indexes of recipients were collected. The risk factors for the occurrence of PTDM in renal transplant recipients were analyzed by univariate and multivariate analysis. The prediction model for PTDM was established and its prediction value was evaluated. Results Family history of diabetes mellitus, body mass index (BMI), preoperative 2 h postprandial blood glucose and preoperative glycosylated hemoglobin were the independent risk factors for the occurrence of PTDM in renal transplant recipients. The prediction model for PTDM was logit (P)=2.199×family history of diabetes (yes=1, no=0)+0.109×BMI+0.151×2 h postprandial blood glucose (mmol/L)+0.508×glycosylated hemoglobin (%)-9.123. The results of receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) of these 4 predictors combined for predicting PTDM in renal transplant recipients was 0.830 [95% confidence interval (CI) 0.786-0.873], the cut-off value was 0.0608, the sensitivity was 0.821, the specificity was 0.700, and the Youden index was 0.521 (P < 0.05). Conclusions Family history of diabetes mellitus, BMI, preoperative 2 h postprandial blood glucose and preoperative glycosylated hemoglobin are the independent risk factors for the occurrence of PTDM in renal transplant recipients. The prediction model for PTDM combined with4 predictors yield relatively high prediction value for PTDM.

Objective:To investigate the subjective experience and processing characteristics of positive and negative emotions in undergraduates who have immigrated to the plateau for a long time.Methods:SPSS 22.0 was used for data analysis.Using independent sample t-test to compare various data from the plateau group(58 undergraduates who had moved to an altitude of 3 658 m for over 2 years after reaching adulthood) with the plain group (58 undergraduates who had never been to the plateau), including the state anxiety inventory(SAI), self-rating depression scale(SDS), positive and negative affect schedule (PANAS), and the affective valency and arousal on the positive, neutral, and negative emotional pictures.And χ 2 test was conducted for the positive detection rates of state anxiety and depression of the two groups.Then, Pearson correlation analysis was performed on SAI, SDS and PANAS scores. Results:The positive detection rates(state-anxiety: 67.24%, depression: 56.90%) and scores of state anxiety(44.45±8.57) and depression(50.12±10.11) in the plateau group were all higher than those in the plain group(46.55%, 32.76%, (40.19±9.58), (44.64±9.17) respectively, χ 2=5.06, 8.12, t=2.52, 3.06, all P<0.05). In addition, positive affect scores of the plateau group (28.16±5.39) tended to be lower than those of the plain group (30.28±6.51), but the difference was not statistically significant( t=-1.91, P=0.059). SAI, SDS and PANAS scores were moderately correlated each other( r= 0.69, -0.52, 0.67, -0.62, 0.53, all P<0.01). Positive affect was mildly negatively correlated with negative affect( r=-0.27, P<0.01). The correlation between positive emotion and depression( r=-0.62) was greater than that between positive emotion and state anxiety( r=-0.52, t=2.57, P<0.05). The correlation between negative emotion and state anxiety( r=0.67) was greater than that between negative emotion and depression( r=0.53, t=1.71, P<0.05). The valency score of neutral images in the plateau group (3.06±0.20) was higher than that in the plain group ((2.99±0.20), t=2.01, P=0.047). Conclusion:The long-term plateau immigrant undergraduates are prone to state anxiety and depression, with depression being the primary and anxiety secondary, and exhibit a positivity bias to neutral stimulus processing.

Objective:To explore the neutral mechanism of influence of long-term exposure to high altitude hypoxia environment on the processing stage of conflict inhibition.Methods:Differences in the electroencephalogram during a 2-1 mapping Stroop task were compared between a high-altitude (HA) group ( n=20) who lived in a high-altitude area (3 650 m) for two years, and a low-altitude (LA) group ( n=20) who had never visited high-altitude areas. Results:The HA group had a higher pulse rate ((82.0±9.7)/min vs (74.0±11.3)/min) and lower oxygen saturation level ((90.7±2.8)% vs (97.4±1.1)%) compared with LA group.Behavior data showed that the reaction time (RT) in congruent (CO) condition was shorter than that in stimulus incogruent (SI) condition, and the RT in SI condition was shorter than that in RI condition ((707.91±70.33)ms vs (753.76±72.96)ms vs (803.88±73.21)ms); accuracy(ACC) rate in SI condition was higher than CO condition, and the ACC in CO condition was higher than RI condition((96.35±2.91)% vs (95.90±2.83)% vs (91.55±5.22)%). And the response conflict effect was larger than the stimulus conflict effect((49.76±33.90) vs (23.60±30.20)). The differences were all statistically significant (all P<0.01). In SI condition, the RT of HA group was longer than LA group((730.43±60.50)ms vs (777.09±78.23)ms) ( P<0.05). As for the EEG, the amplitude of P2((6.18±0.62)μV vs (3.21±0.62)μV) and N450((1.39±1.48)μV vs (5.91±1.48)μV) component of the HA group were higher those that of the LA group.The amplitude of N450 at P4 electrode site was larger than that at P3 electrode site in HA group((2.26±1.34)μV vs (0.62±1.43)μV). The differences were all statistically significant (all P<0.05). Conclusion:Long-term exposure to high altitude hypoxia environment affects the early stage of stimulus perception and task retrieval, as well as the conflict monitoring in later stage of stimulus and response conflict.The HA group need compensation of right parietal to complete the conflict monitoring of stimulus and response conflict.