OBJECTIVES: We propose a new melanoma segmentation model, SG-UNet, to enhance the precision of melanoma segmentation in dermascopy images to facilitate early melanoma detection. METHODS: We utilized a U-shaped convolutional neural network, UNet, and made improvements to its backbone, skip connections, and downsampling pooling sections. In the backbone, with reference to the structure of VGG, we increased the number of convolutions from 10 to 13 in the downsampling part of UNet to achieve a deepened network hierarchy that allowed capture of more refined feature representations. To further enhance feature extraction and detail recognition, we replaced the traditional convolution the backbone section with self-calibrated convolution to enhance the model's ability to capture both spatial and channel dimensional features. In the pooling part, the original pooling layer was replaced by Haar wavelet downsampling to achieve more effective multi-scale feature fusion and reduce the spatial resolution of the feature map. The global attention mechanism was then incorporated into the skip connections at each layer to enhance the understanding of contextual information of the image. RESULTS: The experimental results showed that the SG-UNet model achieved significantly improved segmentation accuracy on ISIC 2017 and ISIC 2018 datasets as compared with other current state-of-the-art segmentation models, with Dice reached 92.41% and 86.62% and IoU reaching 92.31% and 86.48% on the two datasets, respectively. CONCLUSIONS The proposed model is capable of effective and accurate segmentation of melanoma from dermoscopy images.
Melanoma/diagnosis* ; Humans ; Neural Networks, Computer ; Dermoscopy/methods* ; Skin Neoplasms ; Image Processing, Computer-Assisted/methods* ; Calibration ; Algorithms

Objective:To understand the etiological surveillance and drug resistance characteristics of Legionella pneumophila (LP) from the aqueous environment of public places in Shanghai, from 2011 to 2020, and provide evidence for surveillance of the disease. Methods:Environmental water samples were systematically collected from public venues in urban and suburban districts of Shanghai for LP surveillance. All the identified LP isolates underwent a series of testings including serotyping, pulsed field gel electrophoresis (PFGE), sequence-based typing, and antimicrobial susceptibility testing. χ2 test or Cochran-Armitage trend tests were used for statistical analysis and for temporal resistance patterns. Results:Among 6 263 water samples, the LP-positive rate was 20.93% (1 311/6 263). The positivity rate decreased from 24.98% (287/1 149) in 2011-2012 to 20.02% (1 024/5 114) in 2013-2020 ( χ2=13.92, P<0.001), with the highest monthly positivity observed from June to August (23.79%, 745/3 132). A total of 1 365 LP strains were isolated, of which 912 were further characterized, including 10 serotypes, 149 PFGE patterns, and 33 sequence types (ST). The predominant serotype was Lp1 (86.84%, 792/912), and the dominant ST was ST752 (29.50%, 269/912). ST clustering revealed two major clonal groups CG1 and CG2, accounting for 91.12% (831/912) of the isolates. The 190 LPs involved in the drug sensitivity test showed three resistance profiles: azithromycin resistance (31.05%, 59/190), ciprofloxacin resistance (0.53%, 1/190) and azithromycin+ciprofloxacin resistance (0.53%, 1/190). Azithromycin-resistant strains were predominantly ST1 (64.41%, 38/59). The antimicrobial resistance rate showed a significant decline, from 48.65% (18/37) in 2011-2012 to 28.10% (43/153) in 2013-2020 ( χ2=9.38, P=0.002). Conclusions:Compared to from 2011 to 2012, both the positivity rate and antimicrobial resistance prevalence of LP in public aqueous environments of Shanghai exhibited an overall decline from 2013 to 2020. The predominant types of LP were serotype Lp1 and sequence type ST752, with notable high-level resistance to azithromycin. Measures as enhancing the enforcement of water safety regulations and prioritizing surveillance of azithromycin resistance in LP were recommended to mitigate public health risks.

Objective:To understand the etiological surveillance and drug resistance characteristics of Legionella pneumophila (LP) from the aqueous environment of public places in Shanghai, from 2011 to 2020, and provide evidence for surveillance of the disease. Methods:Environmental water samples were systematically collected from public venues in urban and suburban districts of Shanghai for LP surveillance. All the identified LP isolates underwent a series of testings including serotyping, pulsed field gel electrophoresis (PFGE), sequence-based typing, and antimicrobial susceptibility testing. χ2 test or Cochran-Armitage trend tests were used for statistical analysis and for temporal resistance patterns. Results:Among 6 263 water samples, the LP-positive rate was 20.93% (1 311/6 263). The positivity rate decreased from 24.98% (287/1 149) in 2011-2012 to 20.02% (1 024/5 114) in 2013-2020 ( χ2=13.92, P<0.001), with the highest monthly positivity observed from June to August (23.79%, 745/3 132). A total of 1 365 LP strains were isolated, of which 912 were further characterized, including 10 serotypes, 149 PFGE patterns, and 33 sequence types (ST). The predominant serotype was Lp1 (86.84%, 792/912), and the dominant ST was ST752 (29.50%, 269/912). ST clustering revealed two major clonal groups CG1 and CG2, accounting for 91.12% (831/912) of the isolates. The 190 LPs involved in the drug sensitivity test showed three resistance profiles: azithromycin resistance (31.05%, 59/190), ciprofloxacin resistance (0.53%, 1/190) and azithromycin+ciprofloxacin resistance (0.53%, 1/190). Azithromycin-resistant strains were predominantly ST1 (64.41%, 38/59). The antimicrobial resistance rate showed a significant decline, from 48.65% (18/37) in 2011-2012 to 28.10% (43/153) in 2013-2020 ( χ2=9.38, P=0.002). Conclusions:Compared to from 2011 to 2012, both the positivity rate and antimicrobial resistance prevalence of LP in public aqueous environments of Shanghai exhibited an overall decline from 2013 to 2020. The predominant types of LP were serotype Lp1 and sequence type ST752, with notable high-level resistance to azithromycin. Measures as enhancing the enforcement of water safety regulations and prioritizing surveillance of azithromycin resistance in LP were recommended to mitigate public health risks.

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the efficacy of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects who were previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extended or switched TMF treatment for 48 weeks. Efficacy was evaluated based on virological, serological, biological parameters, and fibrosis staging. Statistical analysis was performed using the McNemar test, t-test, or Log-Rank test according to the data. Results:593 subjects from the initial TMF group and 287 subjects from the TDF group were included at week 144, with the proportions of HBV DNA<20 IU/ml at week 144 being 86.2% and 83.3%, respectively, and 78.1% and 73.8% in patients with baseline HBV DNA levels ≥8 log10 IU/ml. Resistance to tenofovir was not detected in both groups. For HBeAg loss and seroconversion rates, both groups showed a further increase from week 96 to 144 and the 3-year cumulative rates of HBeAg loss were about 35% in each group. However, HBsAg levels were less affected during 96 to 144 weeks. For patients switched from TDF to TMF, a substantial further increase in the alanine aminotransferase (ALT) normalization rate was observed (11.4%), along with improved FIB-4 scores.Conclusion:After 144 weeks of TMF treatment, CHB patients achieved high rates of virological, serological, and biochemical responses, as well as improved liver fibrosis outcomes. Also, switching to TMF resulted in significant benefits in ALT normalization rates (NCT03903796).

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the safety profile of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects that previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extending or switching TMF treatment for 48 weeks. Safety profiles of kidney, bone, metabolism, body weight, and others were evaluated.Results:666 subjects from the initial TMF group and 336 subjects from TDF group with at least one dose of assigned treatment were included at week 144. The overall safety profile was favorable in each group and generally similar between extended or switched TMF treatments from week 96 to 144. In subjects switching from TDF to TMF, the non-indexed estimated glomerular filtration rate (by non-indexed CKD-EPI formula) and creatinine clearance (by Cockcroft-Gault formula) were both increased, which were (2.31±8.33) ml/min and (4.24±13.94) ml/min, respectively. These changes were also higher than those in subjects with extending TMF treatment [(0.91±8.06) ml/min and (1.30±13.94) ml/min]. Meanwhile, switching to TMF also led to an increase of the bone mineral density (BMD) by 0.75% in hip and 1.41% in spine. On the other side, a slight change in TC/HDL ratio by 0.16 (IQR: 0.00, 0.43) and an increase in body mass index (BMI) by (0.54±0.98) kg/m 2 were oberved with patients switched to TMF, which were significantly higher than that in TMF group. Conclusion:CHB patients receiving 144 weeks of TMF treatment showed favorable safety profile. After switching to TMF, the bone and renal safety was significantly improved in TDF group, though experienceing change in metabolic parameters and weight gain (NCT03903796).

Objective:To analyze the epidemiological characteristics of a cluster of 5 confirmed COVID-19 cases related with the transmission in incubation period of initial case, and find out the infection source and transmission chain.Methods:According to "The Prevention and Control Protocol for Coronavirus Disease 2019 (Third Edition)" issued by the National Health Commission, a field epidemiological survey was conducted for the 5 cases in January 2020. Nasopharyngeal swabs and sputum samples were collected from them for the detection of 2019-nCoV by real time RT-PCR. Multi prevention and control measures were taken, such as tracking and screening close contacts, medical isolation observation, investigating the epidemiological link, analyzing transmission chain.Results:Case 1, who had common environmental exposure with other COVID-19 cases, got sick on 20 January, 2020 and was confirmed on 1 February. Case 2 became symptomatic on 22 January and was confirmed on 27 January. Case 3 got sick on 25 January and was confirmed on 30 January. Case 4 had illness onset on 20 January and was confirmed on 1 February. Case 5 got sick on 23 January and was confirmed on 31 January. Among the 5 cases, case 2 died and the illness of other cases were effectively controlled. After exclusion of other common exposure factors, case 1 had a 6-hour meeting with case 2 and case 3 on 19 January. Case 2 and case 3 might be infected by case 1 during the incubation period. It is the key point for epidemiological investigation.Conclusion:The epidemiological investigation indicates that the transmission might occur in the incubation period of COVID-19 case, close attention should be paid to it in future COVID-19 prevention and control.

Objective To explore the relationship between nutrition status and activity of daily livingof elders in nursing homes and the mediating effect of physical activity. Methods From Apr to Sep in 2016,320 elders in nursing homes were selected and were surveyed using the standardized tools. The mediating effects were analyzed with PROCESS. Results The scores of elders′ nutrition status, physical function and activities of daily living were (11.88±2.27), (3.61±3.51), (79.13±26.00) points, respectively. And there were 66.9％ elders suffering from activities of living life impaired. The nutrition status were significantly positive correlated with physical function and activities of daily living of elders, and the physical function were significantly positive correlated with activities of daily living of elders. The physical function partly mediated the association between nutrition status and activities of daily living, and the effect was reached to 39.1％. Conclusions The elders′activities of daily life was poor in nursing home in China. The physical function partly mediated the association between nutrition status and activities of daily living. The related departments could combine the long time and short time plans targeting at improving of nutrition status and physical function respectively, to enhance the outcomes of elders in nursing homes.

Objective To explore the immune-microenvironment of the retinas at different stages of retinal degeneration in Royal College of Surgeon (RCS) rats. Methods RCS-rdy--P+(RCS) rats at early stage (P20), middle stage (P40) and late stage (P60) were involved,12 rats at each post-natal day,RCS-rdy+-P+rats severed as control. Relative concentrations of rat cytokines in rat retina homogenate were detected by using Bio-Plex Suspension Array System. Relative expressions of interleukin-2 (IL-2),C-C motif ligand 2 (CCL2),chemokine (C-X-C motif) ligand 9 (CXCL9),CXCL10,CXCL11 and interferon-γ(IFN-γ) mRNA in rat retina were analyzed by real-time PCR. Expressions of IFN-γ and immune cells surface marker CD4,CD8 and CD161 in the retinas were detected by immunohistochemical staining. Percentage of IFN-γ positive T lymphocytes and natural killer(NK) cells in rat retina were analyzed by flow cytometry. The concentrations of IFN-γ in rat retina homogenate were evaluated by enzyme-linked immunosorbent assay ( ELISA ). The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results Lymphocytes related cytokines and chemokines mRNA expression levels in the RCS rat retinas showed increase trends with the extension of time. The expression levels of IL-2,CCL2,CXCL9,CXCL10,CXCL11 and IFN-γ mRNA in P60 RCS rat retinas were significantly increased than those in the P20 RCS rat retinas and the control rat retinas (all at P<0.05).The positive rates of CD4,CD8 and CD161 cells in the retinas of P60 RCS rats was (9.09±0.89)%, (18.77±0.38)% and (9.41±0.38)% ,respectively. The proportion of IFN-γ positive cells in the retinas of P60 RCS rats was (8.29±0.27)%,which was significantly higher than that of the control rats ([0.28±0.02]%),with a significant difference between them (t=29.03,P=0.00). CD4+,CD8+and CD161+lymphocytes were mainly distributed in the retinas of P60 RCS rats, and the expressions of IFN-γ were co-located with lymphocyte surface markers. There were significant differences in the concentrations of IFN-γ in the retinas of RCS rats and control rats at different day ages (Fgroup=16.49,P<0.01; Ftime=21.05,P<0.01),the concentration of IFN-γ in retinas of P60 RCS rats was significantly higher than that of P20 RCS rats, P40 RCS rats and control rats, and the differences were statistically significant ( all at P<0.05). Conclusions Along with the process of retinal degeneration,immune privilege balance in the retinas is disrupted, the expressions of lymphocytes related chemokines and cytokines are elevated. Lymphocytes infiltration and activation are appeared in the retina highly activated at the late stage of RP, leading to the significant up-regulation of inflammatory cytokine IFN-γ in microenvironment, which indicates that lymphocytes mediated immune response may take part in retinal degeneration.

Objective: To investigate the distribution patterns of arboviruses in Yunnan province near the China-Laos-Myanmar border, China, and to provide evidence for prevention and control of arboviruses diseases. Methods: Mosquito samples were collected in Daluo county of Xishuangbanna Dai Autonomous Prefecture and Zhengdong county of Pu’er city in Yunnan province, 2012. Viruses were isolated from the samples by tissue culture, positive isolates were identified by RT-PCR with arbovirus species-specific primers, for further sequencing and phylogenetic analysis. Results: A total of 17 species of mosquitoes from 6 genera were collected. A total of 24 strains of viruses were isolated from the mosquito pools and identified as Tembusu virus (TMUV) (2 strains), Japanese encephalitis virus (JEV) (3 strains), Getah virus (GETV) (2 strains), Banna virus (BAV) (4 strains), Densovirus (DNV) (9 strains) and Nam Dinh virus (NDiV) (3 strains). Conclusions The China-Laos-Myanmar border of Yunnan province is rich in species of mosquitoes and arboviruses.

Objective To investigate students' experiences of learning achieved through the flipped classroom based on Massive Open Online Course(MOOC). Methods Qualitative study in which data were gathered from semi-structured and in-depth interviews conducted with 8 key students from the flipped classroom. The interviews were analyzed using Nancy′s phenomenology 7-step analysis method. Results Four themes emerged from the interviews: personalized learning, active learning, cooperative learning, and the critical role of teacher. Conclusions Overall, our research highlights the efficacy of MOOC-based flipped classroom. The implementation of the flipped classroom in this study improved personalized, active, and cooperative learning, and promoted the positive teacher-student relationship. Further research is needed to continue the investigation into maintaining students′ learning initiatives, controlling teach-learning progression,and strengthening formative evaluation.