{L-End}Objective To understand the prevalence of work-related musculoskeletal disorders (WMSDs) and sickness absence due to WMSDs among key industry workers in Shenzhen City. {L-End}Methods A total of 14 949 workers exposed to dust, noise, chemical and radiation (hereinafter referred to as "traditional occupational groups") in some key industries in Shenzhen City, as well as bus drivers, teachers, medical staff, policemen, courier, sanitation workers and video operators were selected as the research subjects using stratified cluster sampling. The Musculoskeletal Disorders Questionnaire was used to investigate the prevalence of WMSDs and sickness absence due to WMSDs in the past year. {L-End}Results The overall prevalence of WMSDs among the study subjects was 56.3% (8 423/14 949). The prevalence of WMSDs in different body parts from high to low was neck, waist, shoulder, back, knee, wrist, ankle, hip, and elbow, which was 37.6%, 35.7%, 31.7%, 25.2%, 18.3%, 15.4%, 14.9%, 12.4%, and 11.6%, respectively (P<0.01). The overall prevalence of WMSDs among different occupational groups from high to low was teachers, video operators, bus drivers, couriers, medical staff, policemen, traditional occupational groups, and sanitation workers, which was 82.2%, 75.7%, 74.9%, 73.9%, 67.9%, 64.3%, 43.3%, and 31.9%, respectively (P<0.01). The overall rate of sickness absence due to WMSDs was 18.3% (2 736/14 949). The overall rate of sickness absence among different occupational groups from high to low was bus drivers, couriers, teachers, traditional occupational groups, policemen, video operators, medical staff, and sanitation workers, which was 31.6%, 24.5%, 20.9%, 20.2%, 15.2%, 12.4%, 9.3%, and 6.7%, respectively (P<0.01). Among different parts of the body, the highest correlation coefficient of WMSDs was found between neck and shoulder ［correlatioon cofficient (r)=0.648, P<0.01］, while the lowest was between neck and ankle (r=0.303, P<0.01). {L-End}Conclusion The prevalence of WMSDs and sickness absence due to WMSDs among key industry workers in Shenzhen City is relatively high. Comprehensive prevention and control measures should be taken according to the characteristics of occupational population to reduce the impact of WMSDs on the health of occupational population.

{L-End}Objective To investigate the prevalence of neck and waist work-related musculoskeletal disorders (WMSDs) and its relationship with occupational stress among express delivery workers. {L-End}Methods A total of 437 express delivery workers in Shenzhen City were selected as the research subjects using convenient sampling method. The prevalence of neck and waist WMSDs and the level of occupational stress were investigated by the Musculoskeletal Disorder Questionnaire and Work Content Questionnaire. {L-End}Results The prevalences of neck and waist WMSDs among the workers in the past year were 47.6% (208/437) and 60.2% (263/437), respectively. The detection rate of occupatioonal stress was 51.5%(225/437). The prevalences of neck and waist WMSDs among the workers of the occupational stress group were higher than that in the non-occupational stress group (51.9% vs 42.6%, 66.4% vs 53.0%, both P<0.01). The results of multivariate logistic regression analysis showed that the risk of neck WMSDs was higher in workers with weekly working hours >40 hours, workers with poor working posture, and workers with occupational stress compared with workers with weekly working hours ≤40 hours, workers without poor working posture, and workers without occupational stress, respectively (all P<0.05). The risk of waist WMSDs was higher in workers without weekly exercise, workers with poor working posture, and workers with occupational stress compared with workers with weekly exercise, workers without poor working posture, and workers without occupational stress, respectively (all P<0.05). {L-End}Conclusion The prevalence of neck and waist WMSDs, which may be influenced by occupational stress and poor working postures, is relatively high among express delivery workers.

Proteins in the human body are usually made of 20 natural amino acids.Through different amino acid combinations and isomerization, proteins of diverse functions are built.An emerging genetic code expansion technology can introduce unnatural amino acids into specific sites of target protein, endowing the protein with new biological characteristics including covalently binding with proximal proteins, carrying fluorescence, and mimicking specific protein post-translational modifications.In this paper, based on the structure and function of unnatural amino acids, the applications of different types of unnatural amino acids in regulating protein''s stability, studying protein''s conformation, expression level, and localization, and uncovering heretofore unknown protein-protein interactions were reviewed.Besides, genetic code expansion of unnatural amino acids is anticipated to find broad utilities in biomedicine by bringing new ideas and methods to the design and optimization of biologics.

Preoperative treatment of colorectal cancer includes neoadjuvant therapy for initial resectable patients and conversion therapy for initial unresectable patients. In locally advanced rectal cancer, on the basis of neoadjuvant chemoradiotherapy or radiotherapy, increasing the intensity of concurrent chemotherapy, or raising postoperative adjuvant chemotherapy before surgery, or combining with immunotherapy can increase pathological downstaging, contribute to organ preservation, and improve survival of patients. In locally advanced colon cancer, neoadjuvant chemotherapy can improve surgical outcomes. In patients with resectable colorectal liver metastases, neoadjuvant chemotherapy is recommended in patients with unfavorable prognostic factors, but it remains controversial whether it should be combined with targeted therapy. However, in patients with initially unresectable colorectal liver metastases, under the guidance of molecular typing, chemotherapy, especially triple-drug chemotherapy, combined with targeted therapy, is expected to achieve higher objective response rate and convertible rate, thus accepting surgical resection, which improves long-term survival. In addition, for the patients with mismatch repair deficient/micro-satellite instability-high metastatic colorectal cancer, programmed death-1 monoclonal antibody (mAb) and/or cytotoxic T lymphocyte-associated antigen-4 mAb have become the standard first-line treatment option.

Objective:To understand the occurrence of occupational injuries among sanitation workers in Shenzhen, and provide a scientific basis for the prevention of occupational injuries among sanitation workers.Methods:From May to November 2020, a cluster sampling method was used to select some street sanitation workers in Shenzhen to conduct a questionnaire survey. A total of 2200 questionnaires were recovered, of which 2167 were valid (98.5% effective recovery rate) . The socio-demographic data, length of service, type of work and occurrence of occupational injuries of sanitation workers were collected, and the distribution characteristics of occupational injuries and their relationship with factors such as type of work were analyzed.Results:Among the 2167 sanitation workers, 240 (11.1%) had experienced occupational injuries. The most common occupational injuries among sanitation workers were sharp injury, heat stroke and motor vehicle traffic accident, with the incidence rates of 6.1% (133/2167) , 2.4% (53/2167) and 1.7% (36/2167) respectively. There were statistically significant differences in the distribution of occupational injuries among sanitation workers with different lengths of work and types of work ( P<0.05) . The incidence of occupational injury among sanitation workers with more than 5 years of service was significantly higher than that of workers with less than 5 years of service ( P<0.05) . The incidence of sharp injury among garbage sorting and transportation personnel was higher (7.9%, 21/265) , the incidence of heat stroke among manual cleaners was higher (3.1%, 42/1366) , and the incidence of motor vehicle traffic accident among mechanized cleaners was higher (5.4%, 10/184) . Conclusion:There are many cases of occupational injuries among sanitation workers in Shenzhen. Targeted measures should be taken to prevent the occurrence of different types of work and different types of occupational injuries, and to improve the occupational health level of sanitation workers.

Objective:To understand the occurrence of occupational injuries among sanitation workers in Shenzhen, and provide a scientific basis for the prevention of occupational injuries among sanitation workers.Methods:From May to November 2020, a cluster sampling method was used to select some street sanitation workers in Shenzhen to conduct a questionnaire survey. A total of 2200 questionnaires were recovered, of which 2167 were valid (98.5% effective recovery rate) . The socio-demographic data, length of service, type of work and occurrence of occupational injuries of sanitation workers were collected, and the distribution characteristics of occupational injuries and their relationship with factors such as type of work were analyzed.Results:Among the 2167 sanitation workers, 240 (11.1%) had experienced occupational injuries. The most common occupational injuries among sanitation workers were sharp injury, heat stroke and motor vehicle traffic accident, with the incidence rates of 6.1% (133/2167) , 2.4% (53/2167) and 1.7% (36/2167) respectively. There were statistically significant differences in the distribution of occupational injuries among sanitation workers with different lengths of work and types of work ( P<0.05) . The incidence of occupational injury among sanitation workers with more than 5 years of service was significantly higher than that of workers with less than 5 years of service ( P<0.05) . The incidence of sharp injury among garbage sorting and transportation personnel was higher (7.9%, 21/265) , the incidence of heat stroke among manual cleaners was higher (3.1%, 42/1366) , and the incidence of motor vehicle traffic accident among mechanized cleaners was higher (5.4%, 10/184) . Conclusion:There are many cases of occupational injuries among sanitation workers in Shenzhen. Targeted measures should be taken to prevent the occurrence of different types of work and different types of occupational injuries, and to improve the occupational health level of sanitation workers.

Objective:To investigate the risk factors for lymph node metastasis in T1 colorectal cancer and application value of its nomogram prediction model.Methods:The retrospective case-control study was conducted. The clinicopathological data of 914 patients with T1 colorectal cancer who underwent radical resection in the Zhongshan Hospital of Fudan University from June 2008 to December 2019 were collected. There were 528 males and 386 females, aged from 25 to 87 years, with a median age of 63 years. Observation indicators: (1) clinicopathological data of patients with T1 colorectal cancer; (2) follow-up; (3) analysis of influencing factors for lymph node metastasis; (4) development and internal validation of a nomogram predition model. Patients were regularlly followed up once three months within postoperative 2 years and once six months thereafter to detect tumor recurrence and survival. The endpoint of follow-up was at postoperative 5 years. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were represented as M (range). Count data were described as absolute numbers or percentages, and comparison between groups was analyzed using the chi-square test. The Kaplan-Meier method was used to calculate survival rates and draw survival curves. The Log-rank test was used for survival analysis. Univariate and multivariate analyses were performed using the Logistic regression analysis. Based on results of multivariate analysis, a Logistic regressional nomogram for prediction of lymph node metastasis probability was constructed using R language software. The calibration curve was used to evaluate the consistency between probability predicted by the nomogram model and actual observation probability, which was reprensented by a consistency index. The Bootstrap method was used for evaluation of the model performance to receive the calibration curve. The Hosmer-Lemeshow test was used to calculate the goodness of fit in model. Results:(1) Clinicopathological data of patients with T1 colorectal cancer: 687 of 914 patients underwent direct surgery and 227 underwent remedial operation after endoscopic resection. All the 914 patients were confirmed as pT1NxM0 colorectal cancer by pathological examination. The tumor diameter was (2.3±1.2)cm. The pathological catogaries of 914 patients included 865 cases of adenocarcinoma and 49 cases of mucinous adenocarcinoma. The tumor differentiation degree of 914 patients included 727 cases of high or middle differentiation and 187 cases of low differentiation or undifferentiation. Of the 914 patients, 633 cases had submucosal infiltration depth ≥1 000 μm and 281 cases had submucosal infiltration depth <1 000 μm. There were 110 cases with nerve vessel invasion and 804 without nerve vessel invasion. The number of intraoperative lymph node dissection was 13 (range, 1-48). There were 804 cases in stage N0 of N staging, 98 cases in stage N1 and 12 cases in stage N2. There was no perioperative death. (2) Follow-up: 886 of 914 patients were followed up for 25 months (range, 1-129 months). During the follow-up, 24 patients had tumor recurrence or metastasis. The 5-year cumulative tumor recurrence rate of 914 patients was 4.8% and the median recurrence time was 17.0 months. Liver was the main site of tumor recurrence, accounting for 58.3%(14/24). The 5-year recurrence-free survival rate of 914 patients was 95.2%. The 5-year recurrence-free survival rate was 96.3% of 804 patients without lymph node metastasis, versus 86.6% of 110 patients with lymph node metastasis, showing a significant difference between the two groups ( χ2=6.83, P<0.05). (3) Analysis of influencing factors for lymph node metastasis: results of univariate analysis showed that preoperative carcinoembryonic antigen (CEA), preoperative CA19-9, tumor differentiation degree, submucosal infiltration depth, nerve vessel invasion were related factors for lymph node metastasis in T1 colorectal cancer ( odds ratio=2.56, 3.25, 2.21, 2.68, 3.39, 95% confidence interval as 1.41-4.67, 1.22-8.66, 1.43-3.41, 1.56-4.88, 2.10-5.48, P<0.05). Results of multivariate analysis showed that preoperative CEA ≥5 μg/L, preoperative CA19-9 ≥37 U/mL, poor differentiation or undifferentiation, submucosal infiltration depth ≥1 000 μm and nerve vessel invasion were independent risk factors for lymph node metastasis in T1 colorectal cancer ( odds ratio=2.23, 3.47, 2.01, 2.31, 2.91, 95% confidence interval as 1.02-4.15, 1.08-10.87, 1.03-3.27, 1.40-4.47, 1.64-5.13, P<0.05). (4) Development and internal validation of a nomogram predition model: based on results of multivariate Logistic analysis, a nomogram prediction model for lymph node metastasis in T1 colorectal cancer was developed. The nomogram score was 59 for preoperative CEA >5 μg/L, 100 for preoperative CA19-9 ≥37 U/mL, 48 for poor differentiation or undifferentiation, 67 for submucosal infiltration depth ≥1 000 μm and 92 for nerve vessel invasion, respectively. The total of different scores for different clinicopathological factors corresponded to the probability of lymph node metastasis. The receiver operating characteristic curve was drawed to evaluate the predictive performance of nomogram for lymph node metastasis in T1 colorectal cancer, with the area under curve of 0.70(95% confidence interval as 0.64-0.75, P<0.05). The Bootstrap internal validation of predictive performance in the nomogram predition model showed a consistency index of 0.70 (95% confidence interval as 0.65-0.75). The calibration chart showed a good consistency between the probability predicted by the nomogram model and actual probability of lymph node metastasis. The Hosmer-Lemeshow test showed a good fitting effect in model ( χ2=1.61, P>0.05). Conclusions:Preoperative CEA ≥5 μg/L, preoperative CA19-9 ≥37 U/mL, poor differentiation or undifferentiation, submucosal infiltration depth ≥ 1 000 μm and nerve vessel invasion are independent risk factors for lymph node metastasis in T1 colorectal cancer. The constructed nomogram model can help predict the probability of lymph node metastasis in T1 colorectal cancer.

The Corona Virus Disease 2019 (COVID-19) since December, 2019 has a wide range of infection due to the strong infectious characteristics. Both medical staff and patients are at increased risk of infection. It is an urgent clinical problem for specialist doctors to work with diagnosis and treatment of cancer patients during the epidemic situation. Based on the colorectal cancer diagnosis and treatment guidelines (2019 CSCO guideline), combined with their own experience, the authors propose the overall management strategies for colorectal cancer patients. This strategies cover the key diagnosis and treatment of colorectal cancer, and provide targeted clinical practice. These work will be helpful for colorectal cancer specialists to carry out the diagnosis and treatment of colorectal cancer effectively under the epidemic of COVID-19.

Objective:To investigate the risk factors associated with anastomotic leakage after robotic surgery in mid-low rectal cancer.Methods:A retrospective case-control study method was conducted. Inclusion criteria: (1) 18 to 80 years old; (2) pathologically confirmed rectal cancer; (3) distance <10 cm from tumor to anal margin; (4) robotic anterior rectal resection. Patients with previous history of colorectal cancer surgery, distant metastases or other malignant tumors, undergoing emergency surgery, with severe abdominal adhesions or those receiving combined organ resection were excluded. Based on the above criteria, 636 patients undergoing robotic radical sphincter-preserving surgery for mid-low rectal cancer in Zhongshan Hospital from January 2015 to December 2018 were included in this study, including 398 males (62.6%) and 238 females (37.4%) with a mean age of (61.9±11.3) years. Sixty-eight cases (10.7%) received neoadjuvant chemoradiotherapy. Amony the 636 included patients, 123(19.3%) underwent natural orifice specimen extraction surgery (NOSES) and 15 (2.3%) underwent preventive stoma. According to the cirteria developed by the International Rectal Cancer Research Group in 2010, the anastomotic leakage was classified as grade A (no requirement of intervention), B (requirement of intervention), and C (requirement of operation). Logistic regression was used to analyze the relationship between anastomotic leakage and clinicopathological factors. Factors in univariate analysis with P<0.05 were included in the multivariate analysis. Results:Anastomotic leakage occurred in 38 cases (6.0%). The grading of anastomotic leakage was grade A in 13 cases (2.0%), grade B in 19 cases (3.0%), and grade C in 6 cases (0.9%). The 3-year disease-free survival rate of patients with anastomotic leakage and without anastomotic leakage was 83.5% and 83.6% respectively ( P=0.862); the 3-year overall survival rate of the two group was 85.1% and 87.5% respectively ( P=0.296). The results of univariate logistic regression analysis showed that male ( P=0.011), longer operation time ( P=0.042), distance ≤5 cm from tumor to anal margin ( P=0.012), more intraoperative blood loss ( P=0.048) were associated with anastomotic leakage (all P<0.05). NOSES was not associated with anastomotic leakage ( P=0.704). Multivariate analysis confirmed that male (OR=3.03, 95%CI: 1.37 to 7.14, P=0.010), operation time ≥180 minutes (OR=2.04, 95%CI: 1.03 to 3.99, P=0.040), distance ≤5 cm from tumor to anal margin (OR=2.56, 95%CI:1.28 to 5.26, P=0.008) were independent risk factors for anastomotic leakage. Conclusion:Male, short distance from tumor to anal margin, and long operation time are independent risk factors for anastomotic leakage in patients undergoing robotic mid-low rectal cancer radical surgeries. These patients need to be cautiously treated during surgery.

Objective:To investigate the short-term outcomes of laparoscopic simultaneous resection of primary colorectal cancer and liver metastases in patients with resectable synchronous colorectal liver metastases (SCRLM).Methods:A descriptive case series study was performed. Clinicopathological data of patients with SCRLM who underwent laparoscopic simultaneous resection of colorectal cancer and liver metastases in Zhongshan Hospital between December 2015 and September 2018 were retrieved from a prospective colorectal cancer database. Perioperative presentations and short-term outcomes were analyzed.Results:A total of 53 patients were enrolled with average age of(61.7±11.3) years. Among them, 32 were male (60.4%) and 21 were female (39.6%). Twenty-five patients (47.2%) were American Society of Anesthesiologists (ASA) grade I and 28 (52.8%) were grade II. All the patients completed laparoscopic simultaneous resection without conversion. The average operation time was (320.2±114.5) min. The estimated blood loss was 150.0 (45.0-2000.0) ml, and only 2 cases (3.8%) received intraoperative transfusion. Postoperative pathologic results revealed that the average primary tumor size was (5.4±1.9) cm; 4 cases (7.5%) were T1-2 stage and 48 cases (90.6%) were T3-4 stage; 40 patients (75.5%) had lymph node metastasis; 19 (35.8%) had vascular involvement; 24 (45.3%) had neural invasion. The median number of liver metastases was 1.0 (1-8), and the average size of largest liver metastases was (3.0±1.9) cm. The median margin of liver metastases was 1.0 (0.1-3.5) cm, and only 1 case was R1 resection. The average time to the first postoperative flatus was (67.9±28.9) h, and the average time to the liquid diet was (107.0±33.8) h. The average postoperative indwelling catheterization time was (85.6±56.4) h. The average postoperative hospital stay was (9.2±4.4) d, and the average cost was (82±26) thousand RMB. No death within postoperative 30-day was found. The morbidity of postoperative complication was 32.1% (17/53) and 3 patients developed grade III to IV complications which were improved by conservative treatment. The median follow-up period was 23.2 months. During follow-up, 19 patients (35.8%) developed recurrence or metastasis, and 4 (7.5%) died. The 1- and 2-year disease-free survival (DFS) rates were 68% and 47% respectively, and the 1- and 2-year overall survival rates were 95% and 86% respectively.Conclusions:Laparoscopic simultaneous resection of primary colorectal cancer and liver metastases is safe and feasible in selected patients with SCRLM. Postoperative intestinal function recovery is enhanced, and morbidity and oncological outcomes are acceptable.