[Analysis on the current situation and influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative].

Objective: To understand the current situation and the main influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative. Methods: From the list of China's hygienic cities (excluding county-level cities), 61 cities were randomly selected in equal proportion and the eligible respondents were randomly selected by using the "Questionnaire Star" network platform to carry out the online questionnaire survey. A self-made satisfaction evaluation scale was used to investigate the satisfaction of the included respondents with the urban built environment and search for relevant data on the city level. The two-level multi-factor mixed effect model was constructed to analyze the influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative. Results: The age range of 2 465 respondents was mainly between 18 and 40 years old (79.9%), with males being the main group (45.8%). The total score of residents' satisfaction with the built environment of China's hygienic cities was (69.14±13.24) points. Based on four standardized dimensions of sense of gain, the result showed that the satisfaction of urban governance had the highest score (65.08 points), followed by urban environmental sanitation (63.68 points), urban lifestyle (59.97 points) and urban basic function (59.02 points). The analysis results of the two-level multi-factor mixed effect model showed that compared with residents with an annual average concentration of inhalable fine particles in the environment>48 micrograms/cubic meter, residents with an average concentration between 38 and 48 micrograms/cubic meter [ß (95%CI): 1.65 (0.08, 3.21)] and≤37 micrograms/cubic meter or less [ß (95%CI): 1.98 (0.53, 3.43)] had higher satisfaction. Compared with residents whose proportion of the secondary industry to GDP was≤40.9%, residents in cities with a larger proportion had a lower satisfaction level [residents with a proportion of 40.9%-48.03%, ß (95%CI):-2.21 (-3.93, -0.49); residents with a proportion greater than 48.03%, ß (95%CI):-2.58 (-4.58, -0.59)]. Compared with residents with a junior high school or lower education level, residents with a higher education level had a lower satisfaction level [ß (95%CI):-2.37 (-4.57, -0.17)]. Residents of universities and above [ß (95%CI):-3.82 (-6.05, -1.60)], regularly participate in physical exercise [ß (95%CI): 5.78 (4.71, 6.84)] and self-rated good health status [ß (95%CI): 6.39 (5.33, 7.45)] had a higher satisfaction level. Conclusion: The satisfaction of residents with the built environment of China's hygienic cities is still acceptable. Satisfaction is related to individual characteristics such as residents' cultural level, type of residence, frequent participation in physical exercise, and self-rated good health status, as well as urban-level factors such as green coverage rate in built-up areas, annual average concentration of inhalable fine particles, and the proportion of GDP in the secondary industry.

[Performance of screening of contacts of COVID-19 cases in same flight].

Objective: To understand the performance of 2019-nCoV nucleic acid detection in screening of contacts of COVID-19 cases in same flights and provide evidence for the effective screening of persons at high risk for the infection in domestic flights. Methods: The information of passengers who took same domestic flights with COVID-19 cases in China from April 1, 2020 to April 30, 2022 were retrospectively collected,and χ2 test was used to analyze positive nucleic acid detection rates in the passengers in different times before the onsets of the index cases, in different seat rows and in epidemic periods of different 2019-nCoV variants. Results: During the study period, a total of 433 index cases were identified among 23 548 passengers in 370 flights. Subsequently, 72 positive cases of 2019-nCoV nucleic acid were detected in the passengers, in whom 57 were accompanying persons of the index cases. Further analysis of the another 15 passengers who tested positive for the nucleic acid showed that 86.67% of them had onsets or positive detections within 3 days after the diagnosis of the index cases, and the boarding times were all within 4 days before the onsets of the index cases. The positive detection rate in the passengers who seated in first three rows before and after the index cases was 0.15% (95%CI: 0.08%-0.27%), significantly higher than in the passengers in other rows (0.04%, 95%CI: 0.02%-0.10%, P=0.007),and there was no significant difference in the positive detection rate among the passengers in each of the 3 rows before and after the index cases (P=0.577). No significant differences were found in the positive detection rate in the passengers, except the accompanying persons, among the epidemics caused by different 2019-nCoV variants (P=0.565). During the Omicron epidemic period, all the positive detections in the passengers, except the accompanying persons, were within 3 days before the onset of the index cases. Conclusions: The screening test of 2019-nCoV nucleic acid can be conducted in the passengers took the same flights within 4 days before the onsets of the index cases on board. Passengers who seated within 3 rows from the index cases can considered as the close contacts at high risk for 2019-nCoV, for whom screening should be conducted first and special managements are needed. The passengers in other rows can be classified as general risk persons for screening and management.

[Forecasting the burden of disease from diabetes under the scenarios of specific risk factors control in China in 2030].

Objective: To forecast mortality, age-standardized mortality, and probability of premature mortality from diabetes, and to simulate the impact of controlling risk factors by 2030 in China. Methods: We simulated the burden of disease from diabetes in six scenarios according to the development goals of risk factors control by the WHO and Chinese government. Based on the theory of comparative risk assessment and the estimates of the burden of disease for China from the Global Burden of Disease Study 2015, we used the proportional change model to project the number of deaths, age-standardized mortality, and probability of premature mortality from diabetes under different scenarios of risk factors control in 2030. Results: If the trends in exposures to risk factors from 1990 to 2015 continued. Mortality, age-standardized mortality, and probability of premature mortality from diabetes would increase to 32.57/100 000, 17.32/100 000, and 0.84% by 2030, respectively. During that time, mortality, age-standardized mortality and probability of premature mortality for males would all be higher than for females. If the goals of controlling risk factors were all achieved, the number of deaths from diabetes in 2030 would decrease by 62.10% compared to the predicted numbers based on the historical trends in exposure to risk factors, and the probability of premature mortality would drop to 0.29%. If only the exposure to a single risk factor were achieved by 2030, high fasting plasma glucose control would have the greatest impact on diabetes, resulting in a 56.00% reduction in deaths compared to the predicted numbers based on the historical trends, followed by high BMI (4.92%), smoking (0.65%), and low physical activity (0.53%). Conclusions: Risk factors control plays an important role in reducing the number of deaths, age-standardized mortality rate, and probability of premature mortality from diabetes. We suggest taking comprehensive measures to control relevant risk factors for certain populations and regions, to achieve the goal of reducing the burden of disease from diabetes as expected.

Artificial intelligence for detection of intracranial haemorrhage on head computed tomography scans: diagnostic accuracy in Hong Kong.

INTRODUCTION: The use of artificial intelligence (AI) to identify acute intracranial haemorrhage (ICH) on computed tomography (CT) scans may facilitate initial imaging interpretation in the accident and emergency department. However, AI model construction requires a large amount of annotated data for training, and validation with real-world data has been limited. We developed an algorithm using an open-access dataset of CT slices, then assessed its utility in clinical practice by validating its performance on CT scans from our institution. METHODS: Using a publicly available international dataset of >750 000 expert-labelled CT slices, we developed an AI model which determines ICH probability for each CT scan and nominates five potential ICH-positive CT slices for review. We validated the model using retrospective data from 1372 non-contrast head CT scans (84 [6.1%] with ICH) collected at our institution. RESULTS: The model achieved an area under the curve of 0.842 (95% confidence interval=0.791-0.894; P<0.001) for scan-based detection of ICH. A pre-specified probability threshold of ≥50% for the presence of ICH yielded 78.6% accuracy, 73% sensitivity, 79% specificity, 18.6% positive predictive value, and 97.8% negative predictive value. There were 62 true-positive scans and 22 false-negative scans, which could be reduced to six false-negative scans by manual review of model-nominated CT slices. CONCLUSION: Our model exhibited good accuracy in the CT scan-based detection of ICH, considering the low prevalence of ICH in Hong Kong. Model refinement to allow direct localisation of ICH will facilitate the use of AI solutions in clinical practice.

[Residents' sense of acquisition and influencing factors in China's Sanitary City Initiative].

Objective: To analyze the residents' sense of acquisition (recognition, perceptibility and satisfaction) and influencing factors in China's Sanitary City Initiative. Methods: A cross-sectional survey was conducted from December 2020 to February 2021. The data about the residents' sense of acquisition were collected by using questionnaire from 2 465 residents who were aged ≥18 years and had lived in local communities for at least one year in 31, 14 and 16 cities with national sanitary city title in eastern, central and western China the influencing factors of residents' sense of acquisition in China's Sanitary City Initiative were analyzed by using multivariate multilevel model. Results: The total score of residents' sense of acquisition in China's Sanitary City Initiative was 231.15±32.45. After converting the scores according to the 100-score standardized method, the results showed that the recognition score, perception score and the satisfaction score were 85.02, 59.08 and 61.42, respectively. The results of influencing factors analysis showed that education level, gender, marital status, age, prevalence of physical exercise and self-assessment of health status were correlated with the scores of residents' recognition (ß:1.24-2.54,all P<0.05); the concentration of inhalable fine particles , the green coverage of built-up area, the level of GDP per capita and the type of residential community, prevalence of physical exercise and self-assessment of health status were correlated with the score of residents' perception (ß:1.76-8.86,all P<0.05); the concentration of inhalable fine particles , the green coverage of built-up area, the level of GDP per capita and the type of residential community, education level, prevalence of physical exercise and self-assessment of health status were correlated with the score of residents' satisfaction (ß:1.34-6.26,all P<0.05). Conclusions: The total score of residents' sense of acquisition in China's Sanitary City Initiative was relatively high, indicating that the policy has been widely recognized. The detailed management of policy implementation should be strengthened in the future, and more attention needs to be paid to actual needs of the residents to further improve the residents' sense of acquisition in China's Sanitary City Initiative.

Chest computed tomography analysis of lung sparing morphology: differentiation of COVID-19 pneumonia from influenza pneumonia and bacterial pneumonia using the arched bridge and vacuole signs.

INTRODUCTION: This study evaluated the arched bridge and vacuole signs, which constitute morphological patterns of lung sparing in coronavirus disease 2019 (COVID-19), then examined whether these signs could be used to differentiate COVID-19 pneumonia from influenza pneumonia or bacterial pneumonia. METHODS: In total, 187 patients were included: 66 patients with COVID-19 pneumonia, 50 patients with influenza pneumonia and positive computed tomography findings, and 71 patients with bacterial pneumonia and positive computed tomography findings. Images were independently reviewed by two radiologists. The incidences of the arched bridge sign and/or vacuole sign were compared among the COVID-19 pneumonia, influenza pneumonia, and bacterial pneumonia groups. RESULTS: The arched bridge sign was much more common among patients with COVID-19 pneumonia (42/66, 63.6%) than among patients with influenza pneumonia (4/50, 8.0%; P<0.001) or bacterial pneumonia (4/71, 5.6%; P<0.001). The vacuole sign was also much more common among patients with COVID-19 pneumonia (14/66, 21.2%) than among patients with influenza pneumonia (1/50, 2.0%; P=0.005) or bacterial pneumonia (1/71, 1.4%; P<0.001). The signs occurred together in 11 (16.7%) patients with COVID-19 pneumonia, but they did not occur together in patients with influenza pneumonia or bacterial pneumonia. The arched bridge and vacuole signs predicted COVID-19 pneumonia with respective specificities of 93.4% and 98.4%. CONCLUSION: The arched bridge and vacuole signs are much more common in patients with COVID-19 pneumonia and can help differentiate COVID-19 pneumonia from influenza and bacterial pneumonia.

[Prediction on the cardio-cerebrovascular death and probability of premature death caused by common risk factors in China in 2030].

Objective: Predictive models were used to evaluate the impact of common risk factors on the number of cardio-cerebrovascular deaths and the probability of premature death. Methods: Using the data for China estimated by the Global Burden of Disease study 2015 (GBD 2015), we calculated the population attribution fraction (PAF) of risk factors. The proportional change model was used to estimate the number of unattributable deaths by 2030, and to predict the number of deaths, mortality, standardized mortality and probability of premature death by 2030. Results: According to the natural change trend of risk factors from 1990 to 2015, the number of deaths and mortality would reach 6.12 million and 428.53/100 000 by 2030, with an increase of 59.92% and 52.87%. By 2030, the probability of premature death from cardio-cerebrovascular diseases among Chinese aged 30-70 years old would continue to decline, from 11.43% to 11.28% for men, and from 5.79% to 4.43% for women. If the goals of all included risk factors were reached by 2030, 2 289 200 cardio-cerebrovascular deaths would be avoided. If only the exposure to a single risk factor was achieved by 2030, blood pressure, total cholesterol, and fine particulate matter exposure were the three most important factors affecting cardio-cerebrovascular deaths, which would reduce 1 332 800, 609 100 and 306 800 deaths, respectively. Among the involved risk factors, the control of blood pressure would mostly decrease the number of deaths due to ischemic heart disease and hemorrhagic stroke, about 677 300 and 391 100 deaths, accordingly. Conclusion: The control of risk factors is of great significance in reducing deaths and probability of premature death due to cardio-cerebrovascular diseases. If the control targets of all risk factors could be achieved by 2030, the burden of cardio-cerebrovascular diseases would be reduced greatly.

[Spatiotemporal evolution of COVID-19 epidemic in the early phase in China].

Objective: Based on the geographic information systems, we exploreed the spatiotemporal clustering and the development and evolution of COVID-19 epidemic at prefectural level in China from the time when the epidemic was discovered to the time when the lockdown ended in Wuhan. Methods: The information and data of the confirmed COVID-19 cases from December 8, 2019 to April 8, 2020 were collected from 367 prefectures in China for a spatial autocorrelation analysis with software GeoDa, and software ArcGIS was used to visualize the results. Software SatScan was used for spatiotemporal scanning analysis to visualize the hot-spot areas of the epidemic. Results: The incidence of new cases of COVID-19 had obvious global autocorrelation and the partial autocorrelation results showed that incidence of COVID-19 had different spatial distribution at different times from December 8, 2019 to March 4, 2020. There was no significant difference in global autocorrelation coefficient from March 5, 2020 to April 8, 2020. The statistical analysis of spatiotemporal scanning identified two kinds of spatiotemporal clustering areas, the first class clustering areas included 10 prefectures, mainly distributed in Hubei, from January 13 to February 25, 2020. The secondary class clustering areas included 142 prefectures, mainly distributed in provinces in the north and east of Hubei, from January 23 to February 1, 2020. Conclusions: There was a clear spatiotemporal correlation in the distribution of the outbreaks in the early phase of COVID-19 epidemic (December 8, 2019-March 4, 2020) in China. With the decrease of the case and effective prevention and control measures, the epidemics had no longer significant correlations among areas from March 5 to April 8. The study results showed relationship with time points of start and adjustment of emergency response at different degree in provinces. Furthermore, improving the early detection of new outbreaks and taking timely and effective prevention and control measures played an important role in blocking the transmission.

[Prediction on the burden of disease of chronic obstructive pulmonary disease and simulation of the effectiveness of controlling risk factors in China by 2030].

Objective: To forecast the burden of chronic obstructive pulmonary disease (COPD) in China by 2030 and evaluate the effectiveness of controlling risk factors based on the predictive model. Methods: Based on the relationship between the death of COPD and exposure to risk factors and the theory of comparative risk assessment, we used the estimates of the Global Burden of Disease Study 2015 (GBD2015) for China, targets for controlling risk factors, and proportion change model to project the number of deaths, standardized mortality rate, and probability of premature mortality from chronic respiratory diseases by 2030 in different scenarios and to evaluate the impact of controlling the included risk factors to the disease burden of COPD in 2030. Results: If the trends in exposure to risk factors from 1990 to 2015 continued, the number of deaths and the mortality for COPD would be 1.06 million and 73.85 per 100 000 population in China by 2030, respectively, with an increase of 15.81% and 10.69% compared to those in 2015. Compared to 2015, the age-standardized mortality rate would decrease by 38.88%, and the premature mortality would reduce by 52.73% by 2030. If the smoking rate and fine particulate matter (PM2.5) concentration separately achieve their control targets by 2030, there would be 0.34 and 0.27 million deaths that could be avoided compared to the predicted numbers based on the natural trends in exposure to risk factors and the probability of premature death would reduce to 0.59% and 0.52%, respectively. If the control targets of all included risk factors were achieved by 2030, a total of 0.53 million deaths would be averted, and the probability of premature death would decrease to 0.44%. Conclusions: If the exposures to risk factors continued as showed from 1990 to 2015, the number of deaths and mortality for COPD would increase by 2030 compared to 2015, and the standardized mortality and the probability of premature death would decrease significantly, which would achieve the targets of preventing and controlling COPD. If the exposure to the included risk factors all achieved the targets by 2030, the burden of COPD would be reduced, suggesting that the control of tobacco use and air pollution should be enhanced to prevent and control COPD.

[Prediction of disease burden caused by malignant cancer in the context of risk factor control in China, 2030].

Objective: To predict the number of deaths, standardized mortality and probability of premature mortality caused by malignant cancer in the context of risk factor control at different levels in China in 2030, and assess the possibility of achieving the target of reducing the probability of premature mortality of malignant cancer. Methods: According to the risk factor control standard for malignant cancer used both at home and abroad, the results of China from Global Burden of Disease Study 2015 were used to calculate the population attributable fraction of the risk factors. Based on the comparative risk assessment theory, the deaths of malignant cancer were classified as attributable deaths and un-attributable deaths. Proportional change model was used to predict risk factor exposure and un-attributable deaths of malignant cancer in the future, then the number of deaths, standardized mortality rate and probability of premature mortality of malignant cancer in 2030 was estimated. Data analyses were performed by using software R 3.6.1. Results: If the risk factor exposure level during 1990-2015 remains, the number of deaths, standardized mortality rate, and probability of premature mortality of malignant cancer would increase to 3.62 million, 153.96/100 000 and 8.92% by 2030, respectively. If the risk factor exposure control level meets the requirement, the probability of premature mortality from cancer in people aged 30-70 years would drop to 7.57% by 2030. Conclusions: The control of risk factor exposure will play an important role in reducing deaths, standardized mortality rate and probability of premature mortality of malignant cancer. But more efforts are needed to achieve the goals of Health China Action.

[Diagnosis and treatment for emphysematous pyelonephritis: analysis of 14 cases from a single centre].

Objective: To examine the modalities of treatment and clinical outcomes of emphysematous pyelonephritis (EPN), in order to improve the survival rate of EPN patients. Methods: Totally 14 patients diagnosed as EPN between October 2011 and November 2020 at Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine were included in this article. Data collection including patient demographics, clinical manifestations, management and clinical outcomes were conducted by retrospective charts review, after receiving the institutional review board's approval. There were 11 females and 3 males with a median age of 59 years (range: 52 to 73 years). The lesions were located on the left side in 10 patients and right side in 4 patients. All the 14 patients suffered from fever, and present with severe sepsis or septic shock. The median time from symptom onset to admission to hospital was 3 days(range: 2 to 5 days). All cases had diabetes mellitus. Escherichia coli was the most common organism been cultured (11 cases), while Klebsiella pneumonia was the second (3 cases). CT scan showed bubbly or located gas in the renal parenchyma in 5 cases and presence of steaky or mottled gas in the renal parenchyma in 9 cases. All patients had been admitted to ICU for anti-septic shock therapy. Three patients had undergone percutaneous catheter drainage along with broad-spectrum antibiotics therapy while 3 patients had immediate nephrectomy, the other 8 cases had a combination of an initial percutaneous catheter drainage and second stage nephrectomy. Results: In this case series, 3 patients were died from EPN while the other 11 were survived. The median ICU stay time was 6 days (range: 3 to 11 days). Of the 3 patients died from EPN, 2 had undergone percutaneous catheter drainage along and 1 had received immediate nephrectomy. Among the 11 patients who were survived, only 1 had received percutaneous catheter drainage while the other 10 received nephrectomy (8 patients had staged nephrectomy). Follow-up was performed 6 months after discharge. Of the 11 surviving patients, 2 were lost to follow-up, and the remaining 9 patients had an creatine level of (118.4±29.4) µmol/L (range: 89 to 176 µmol/L). Conclusions: For patients coupled with diabetes who were initially diagnosed as acute pyelonephritis, the possibility of EPN should be considered when the disease progressed rapidly especially septic shock occurred. On the basis of empirical broad-spectrum antibiotics therapy and standardized anti-septic shock treatment, a combination of an initial percutaneous catheter drainage and second stage nephrectomy could be efficacious.

[Effects of porcine acellular dermal matrix combined with human epidermal stem cells on wound healing of full-thickness skin defect in nude mice].

Objective: To explore the effects of porcine acellular dermal matrix (ADM) combined with human epidermal stem cells (ESCs) on wound healing of full-thickness skin defect in nude mice. Methods: The morphology of porcine ADM was analyzed by photograph of digital camera, the cell residues in porcine ADM were observed by hematoxylin-eosin (HE) staining, the surface structure of porcine ADM was observed by scanning electron microscope, the secondary structure of porcine ADM was analyzed by infrared spectrometer, the porcine ADM particle size was analyzed by dynamic light scattering particle size analyzer, and the porcine ADM potential was analyzed by nano-particle size potentiometer. The morphology of porcine ADM was observed by inverted fluorescence microscope when it was placed in culture medium for 30 min, 1 d, and 5 d (n=2). The porcine ADM was divided into 5 min group, 10 min group, 20 min group, 30 min group, 60 min group, and 120 min group according to the random number table (the same grouping method below) in static state at normal temperature for the corresponding time to calculate the water absorption by weighing method (n=3). Swiss white mouse embryonic fibroblasts (Fbs) were divided into blank control group (culture medium only), and 50.0 g/L ADM extract group, 37.5 g/L ADM extract group, 25.0 g/L ADM extract group, 12.5 g/L ADM extract group, and 6.5 g/L ADM extract group which were added with the corresponding final concentrations of ADM extract respectively. At post culture hour (PCH) 24, 48, and 72, the cell survival rate was detected by cell counting kit 8 and the cytotoxicity was graded (n=5). The erythrocytes of a 6-week-old male Sprague-Dawley male rat were divided into normal saline group, ultra-pure water group, and 5 mg/mL ADM extract group, 10 mg/mL ADM extract group, and 15 mg/mL ADM extract group which were treated with the corresponding final concentrations of porcine ADM extract respectively. After reaction for 3 h, the absorbance value of hemoglobin was detected by microplate reader to represent the blood compatibility of porcine ADM (n=3). ESCs were isolated and cultured from the discarded prepuce of a 6-year-old healthy boy who was treated in the Department of Urology of the First Affiliated Hospital of Army Medical University (the Third Military Medical University) in July 2020, and then identified by flow cytometry. The porcine ADM particles of composite ESC (hereinafter referred to as ESC/ADM) were constructed by mixed culture. After 3 days of culture, the composite effect of ESC/ADM was observed by HE staining and laser scanning confocal microscope. Thirty-six 7-8-week-old male non-thymic nude mice were divided into phosphate buffer solution (PBS) alone group, ADM alone group, ESC alone group, and ESC/ADM group, with 9 mice in each group, and the wound model of full-thickness skin defect was established. Immediately after injury, the wounds were treated with the corresponding reagents at one time. On post injury day (PID) 1, 7, 11, and 15, the wound healing was observed and the wound healing rate was counted (n=3). On PID 7, the epithelialization of wounds was observed by HE staining and the length of un-epithelialized wound was measured (with this and the following sample numbers of 4). On PID 11, the dermal area and collagen deposition of wounds were observed by Masson staining and the dermal area of wound section was calculated, the number of cells expressing CD49f, a specific marker of ESC, was calculated with immunofluorescence staining, the mRNA expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in ESC after wound transplantation was detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction. Data were statistically analyzed with independent sample t test, one-way analysis of variance, analysis of variance for repeated measurement, and least significant difference t test. Results: The porcine ADM was white particles and composed of reticular structure, with no cells inside, disordered structure, and rough surface. The absorption peak of porcine ADM appeared at the wave numbers of 1 659, 1 549, and 1 239 cm-1, respectively. The main particle size distribution of porcine ADM in solution was 500 to 700 nm, with negative charge on the surface. The morphology of porcine ADM in static state at 30 min and on 1 and 5 d was relatively stable. The water absorption of porcine ADM remained relatively high level in static state from 30 min to 120 min. The cytotoxicity of mouse embryonic Fbs in 6.5 g/L ADM extract group, 12.5 g/L ADM extract group, and 25.0 g/L ADM extract group was grade 1 at PCH 24, and the cytotoxicity of the other groups was 0 grade at each time point. After reaction for 3 h, the absorbance value of hemoglobin of erythrocytes in ultra-pure water group was significantly higher than the values in normal saline group and 15 mg/mL ADM extract group (with t values of 8.14 and 7.96, respectively, P<0.01). After 3 days of culture, the cells of the fourth passage showed pebble-like morphology, with low expression of CD71 and high expression of CD49f, which were identified as ESCs. There was ESC attachment and growth on porcine ADM particles. On PID 1, the wound sizes of nude mice were almost the same in PBS alone group, ADM alone group, ESC alone group, and ESC/ADM group. On PID 7, 11, and 15, the wound contraction of nude mice in each group was observed, especially in ADM alone group, ESC alone group, and ESC/ADM group. On PID 7, the wound healing rates of nude mice in ESC alone group and ESC/ADM group were significantly higher than the rate in PBS alone group (with t values of 2.83 and 4.72 respectively, P<0.05 or P<0.01). On PID 11, the wound healing rate of nude mice in ESC/ADM group was significantly higher than that in PBS alone group (t=4.86, P<0.01). On PID 15, the wound healing rates of nude mice in ADM alone group, ESC alone group, and ESC/ADM group were significantly higher than the rate in PBS alone group (with t values of 2.71, 2.90, and 3.23 respectively, P<0.05). On PID 7, the length of un-epithelialized wound of nude mice in ADM alone group, ESC alone group, and ESC/ADM group was (816±85), (635±66), and (163±32) µm, respectively, which were significantly shorter than (1 199±43) µm in PBS alone group (with t values of 5.69, 10.19, and 27.54 respectively, P<0.01). On PID 11, the dermal areas of wound section of nude mice in ADM alone group, ESC alone group, and ESC/ADM group were significantly larger than the area in PBS alone group (with t values of 27.14, 5.29, and 15.90 respectively, P<0.01); the collagen production of nude mice in ADM alone group and ESC/ADM group was more obvious than that in PBS alone group, and the collagen production of nude mice in ESC alone group and PBS alone group was similar. On PID 11, in the wounds of nude mice in ESC alone group and ESC/ADM group, the cells with positive expression of CD49f were respectively 135±7 and 185±15, and the mRNA expressions of GAPDH were positive; while there were no expressions of CD49f nor mRNA of GAPDH in the wounds of nude mice in PBS alone group and ADM alone group. Conclusions: ESC/ADM particles can promote the wound healing of full-thickness skin defects in nude mice, which may be related to the improved survival rate of ESCs after transplantation and the promotion of dermal structure rearrangement and angiogenesis by ADM.

[Robot-assisted nephroureterectomy requiring no robot redocking or patient repositioning: experience from a single center with 62 cases].

Objective: To examine a new technique of robot-assisted nephroureterectomy without robot reldocking or patient repositioning. Methods: Patients diagnosed as upper tract urothelial carcinoma treated with this modality between November 2015 and January 2019 at Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine were included in this analysis. Data collection including patient demographics, operative procedure and postoperative morbidities were conducted by retrospective charts review, after receiving the institutional review board's approval. There were 35 males and 27 females with a median age of 70 years (range: 30 to 91 years) underwent single docking robot-assisted nephroureterectomy without repositioning. Among the 62 cases, 37 patients had pelvic carcinoma while 25 patients had ureteral carcinoma (with proximal portion 12 cases, middle portion 5 cases and distal portion 8 cases). The patient was placed in a 60 to 80-degree, modified flank position with a 15-degree Trendelenburg tilt. The contralateral arm was positioned perpendicular to the torso on an arm board while the ipsilateral arm was taped to the patient's side with ample padding. The robot cart was then docked at a 90-degree angle, perpendicular to the patient. A "W"-shape, three robotic-arm configurations was used for port placement. Results: The surgical procedures were performed successfully in all the 62 patients. The operation time was (171.6±54.7) minutes (range: 60 to 370 minutes). The estimated blood loss during the operation was 50(50) ml (range: 20 to 400 ml) with 4 patients had transfusion. No perioperative death was encountered. Eleven patients had post-operative complications (Clavien-Dindo grade 2) including 3 cases of hemorrhage and 8 cases of chylous leakage. All cases were regularly followed up with a median time of 37 months (range: 17 to 55 months). There were 8, 30, 19, 4 and 1 case followed up for 48, 36, 24, 18 and less than 18 months, respectively. Three patients had reginal recurrences and 11 cases of distant metastasis occurred, with 5 patients died for cancer. The survival rate within 24 months was estimated as 75.4%(43/57). Conclusion: Robot-assisted nephroureterectomy without robot redocking or patient repositioning could be safely reproduced, with surgical outcomes comparable to other established techniques.

[An evidence-based analysis comparing two approaches of robot-assisted laparoscopic radical prostatectomy: the standard technique and Retzius-sparing technique].

Objective: To compare the postoperative outcomes and urinary continence recovery time between standard robotic-assisted laparoscopic radical prostatectomy (RARP) and Retzius-sparing robotic-assisted laparoscopic radical prostatectomy (RsRARP). Methods: A total of 92 patients with low to intermediate-risk prostate cancer who underwent RARP (n=52) and RsRARP (n=40) in Sir Run Run Shaw Hospital from October, 2016 to January, 2018 were retrospectively reviewed. Perioperative data (operative time, estimated blood loss, complications, postoperative staging, postoperative Gleason score) and surgical outcomes (rate of margin positive, urinary continence recovery time) of RARP and RsRARP group were comparatively analyzed. Results: All 92 cases were successfully performed with robot. RARP group had a significantly shorter mean operative time when compared with that in RsRARP group ((103±23) min vs (130±26) min, P<0.05). The two groups had comparable estimated blood loss ((100±54) ml vs (103±64) ml, P>0.05), rate of postoperative infection (5.8% (3/52) vs 5.0% (2/40), P>0.05) and rate of postoperative urine leakage (3.8%(2/52) vs 2.5%(1/40), P>0.05). The two groups had a comparable rate of margin positive (7.7%(4/52) vs 12.5%(5/40), P>0.05). Compared with RsRARP group, the RARP group had a lower rate of urinary continence recovery immediately after the catheter removing at 1 week, 1 month and 3 months after the operation (all P>0.05). The two group had a comparable rate of urinary continence recovery at 6 months after the operation (P>0.05). Conclusion: The RsRARP technique has a good tumor control and obvious advantage of early urinary continence recovery compared with the standard RARP technique. RsRARP technique is safe and effective for the treatment of localized prostate cancer.

[Threshold effects of body mass index on the bone mineral density of Chinese rural women in fluorosis area].

To explore the threshold effect of body mass index (BMI) on bone mineral density (BMD) in Chinese women living in the fluorosis area, we conducted a cross-sectional study and recruited 722 women in rural areas in Henan Province, China. After detection and analyses, we found that compared with the normal BMI group, the risk of osteoporosis in the overweight and obese groups were reduced by 32% and 69%, respectively. Threshold effect analysis showed that BMD was positively correlated with BMI when BMI was 16.8-31.2 kg/m2; while when BMI was greater than 31.2 kg/m2, the correlation reached saturation. The correlation observed between low-to-moderate fluoride exposure and BMD in rural women was not significant.

[Quantitative analysis of national hygienic city policies in China from the perspective of policy tools].

Objective: To give some suggestions on the policy optimization of the establishment of National Hygienic City from the perspective of policy system. Methods: Policy documents were searched in WanFang Database and websites of ministries and commissions directly affiliated to the State Council with the key words of hygienic city, and analyzed by using the content analysis and quantitative analysis, based on the theory and perspective of policy tools and the two-dimensional analysis framework. Results: Among the 161 policy documents, supply-based, environment-based, and demand-based policy tools accounted for 6.83% (11/161), 83.85% (135/161), and 9.32% (15/161) respectively. Policy planning, policy implementation, policy supervision, and policy evaluation tools accounted for 10.56% (17/161), 63.35% (102/161), 21.74% (35/161), and 4.35% (7/161) respectively. Conclusion: The government should reduce its dependence on environmental policy tools, especially strategic measures, and attach importance to the use of supply-based policy tools and demand-based policy tools. At the same time, it should pay attention to the formulation of more practical policy tools in the process of policy evaluation.

[Multiple linear regression models with natural logarithmic transformations of variables].

In general, the application conditions of linear regression models could be met after the natural logarithmic transformation of data. From the practical perspective, this paper introduced the linear regression models with natural logarithmic transformation of independent variable, dependent variable, and both independent and dependent variables in detail. The paper illustrated why the equation and coefficients could not be directly explained after the natural logarithmic transformation of data. The percentage changes of X and/or Y were applied to elaborate the principle and method for the explanation of the equation and coefficients. Three examples were used to fit simple linear models with natural logarithmic transformation of independent, dependent, and both independent and dependent variables and the results of theses models were explained in detail.

[A pathological report of three COVID-19 cases by minimal invasive autopsies].

Objective: To investigate the pathological characteristics and the clinical significance of novel coronavirus (2019-nCoV)-infected pneumonia (termed by WHO as coronavirus disease 2019, COVID-19). Methods: Minimally invasive autopsies from lung, heart, kidney, spleen, bone marrow, liver, pancreas, stomach, intestine, thyroid and skin were performed on three patients died of novel coronavirus pneumonia in Chongqing, China. Hematoxylin and eosin staining (HE), transmission electron microcopy, and histochemical staining were performed to investigate the pathological changes of indicated organs or tissues. Immunohistochemical staining was conducted to evaluate the infiltration of immune cells as well as the expression of 2019-nCoV proteins. Real time PCR was carried out to detect the RNA of 2019-nCoV. Results: Various damages were observed in the alveolar structure, with minor serous exudation and fibrin exudation. Hyaline membrane formation was observed in some alveoli. The infiltrated immune cells in alveoli were majorly macrophages and monocytes. Moderate multinucleated giant cells, minimal lymphocytes, eosinophils and neutrophils were also observed. Most of infiltrated lymphocytes were CD4-positive T cells. Significant proliferation of type Ⅱ alveolar epithelia and focal desquamation of alveolar epithelia were also indicated. The blood vessels of alveolar septum were congested, edematous and widened, with modest infiltration of monocytes and lymphocytes. Hyaline thrombi were found in a minority of microvessels. Focal hemorrhage in lung tissue, organization of exudates in some alveolar cavities, and pulmonary interstitial fibrosis were observed. Part of the bronchial epithelia were exfoliated. Coronavirus particles in bronchial mucosal epithelia and type Ⅱ alveolar epithelia were observed under electron microscope. Immunohistochemical staining showed that part of the alveolar epithelia and macrophages were positive for 2019-nCoV antigen. Real time PCR analyses identified positive signals for 2019-nCoV nucleic acid. Decreased numbers of lymphocyte, cell degeneration and necrosis were observed in spleen. Furthermore, degeneration and necrosis of parenchymal cells, formation of hyaline thrombus in small vessels, and pathological changes of chronic diseases were observed in other organs and tissues, while no evidence of coronavirus infection was observed in these organs. Conclusions: The lungs from novel coronavirus pneumonia patients manifest significant pathological lesions, including the alveolar exudative inflammation and interstitial inflammation, alveolar epithelium proliferation and hyaline membrane formation. While the 2019-nCoV is mainly distributed in lung, the infection also involves in the damages of heart, vessels, liver, kidney and other organs. Further studies are warranted to investigate the mechanism underlying pathological changes of this disease.