Objective To analyze the concentration of heavy metal elements, C, N and H in PM2.5 in the atmosphere in Hangzhou. Methods Midflow samplers were used to collect the samples in Hangzhou city, the element analyzer and microwave digestion ICP-MS were applied to test the samples. Results The average concentrations of N, C, H were 13.9-14.7, 30.3-30.8 and 7.9-8.9 ?g/m3 respectively in the central and northern east areas. The average mass percent values for the three elements(N、C、H) in the city were 12.8%, 27.8% and 8.1% respectively. The average ratios of total inorganic nitrogen to total organic nitrogen (IN/ON) and total organic hydrogen to total inorganic hydrogen (OH/IH) varied in the range of 2.2-3.5 and 3.5-3.6. Eleven elements showed a higher concentration in PM2.5, in which the values of Zn, Pb, Cu and Mn were all more than 200-11 500 mg/kg and the values of Cr, Ni, Se, Mo, Cd and Sb were 17-108 mg/kg, and that was only 6-8 mg/kg for Ag. The levels of average mass percent of all the metal elements were 1.7%-2.0%. Conclusion Carbon is one of important components in PM2.5 in Hangzhou. N and H exist mainly in the form of inorganic and organic compounds respectively. Zn, Pb, Cu, Mn are major heavy metal elements in PM2.5.

Objective:To investigate the application value of three-dimensional visualization technology in management of middle hepatic vein (MHV) processing in associating liver partition and portal vein ligation for staged hepatectomy(ALPPS).Methods:The retrospective and descriptive study was conducted. The clinical data of 40 patients with right massive liver cancer or multiple right liver lesions who underwent ALPPS in the First Affiliated Hospital of Guangxi Medical University from November 2017 to August 2019 were collected. There were 34 males and 6 females, aged (44±9)years, with a range from 26 to 64 years. All patients underwent multi-slice computed tomography (CT) plain and enhanced scan of superior abdominal region before operation, and the data were transmitted to the liver visualization analysis software IQQA system with 1.5 mm thin-layer images to complete the three-dimensional reconstruction of the liver and its blood vessels. Patients were performed ALPPS based on results of three-dimensional reconstruction and intraoperative findings. Observation indicators: (1) results of preoperative three-dimensional reconstruction; (2) surgical situations; (3) follow-up. Follow-up was conducted using outpatient examinations and telephone interview to detect postopeartive survival of patients up to March 2020. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distribution were described as M (range). Count data were represented as absolute numbers. Results:(1) Results of preoperative three-dimensional reconstruction: 40 patients underwent three-dimensional reconstruction successfully, of which 37 clearly showed MHV, tumor location and relationship between them, 3 patients showed unclearly MHV and were classified based on two-dimensional images. Of the 40 patients, 12 had MHV classified as type A, 13 as type B, 9 as type C, and 6 as type D. Three-dimensional reconstruction of vessels showed 22 with umbilical veins and 9 with anterior veins. Of the 40 patients, 35 were predicted to preserve MHV, and 5 were predicted to resect MHV. Total estimated liver volume, tumor volume, and reserved liver volume were (1 012±119)cm 3, 600 cm 3(8-2 055 cm 3), (346±80)cm 3. The ratio of future liver remnant to standard liver volume was 34%±8%. (2) Surgical situations : 40 patients underwent the first-stage ALPPS, including 35 with preservation of MHV and 5 with resection of MHV, which was accorded with preoperative prediction. Thirty-four patients underwent the second-stage ALPPS, and 6 patients had failure to receive the second-stage ALPPS due to undificiency future liver remnant. The operation time and volume of intraoperative blood loss for 40 patients undergoing first-stage ALPPS were (350±79)minutes and 300 mL(range, 100-2 600 mL). Three patients received blood transfusion and no perioperative death occurred. There were 24 patients with grade A heptic insufficiency according to criteria of International StudyGroup of Liver Surgery (ISGLS) and 16 patients with grade B heptic insufficiency after the first-stage ALPPS. Twenty-eight patients had grade Ⅰ complications of Clavien-Dindo classification, including 17 with a small pleural effusion, 10 with a small pleural and abdominal effusion, 1 with hypoproteinemia; 8 patients had grade Ⅱ complications of Clavien-Dindo classification, including 5 with pneumonia, 1 with pneumonia combined with pleural and abdominal effusion, 1 with coagulation disorders, 1 with biliary fistula; 3 patients had grade Ⅲ complications of Clavien-Dindo classification, including 2 with pneumothorax and pneumonia, 1 with pneumothorax, pneumonia and coagulation disorders; 1 patient had grade Ⅳ complications of Clavien-Dindo classification as systemic inflammatory response syndrome. All patients with complications were improved after symptomatic treatment, anti infection, transfusion of fresh frozen plasma or drainage. For the 34 patients undergoing the second-stage ALPPS, the operation time and volume of intraoperative blood loss were (320±83)minutes and 500 mL(range, 200-6 000 mL). Twelve patients received blood transfusion. There were 12 patients with grade A heptic insufficiency according to criteria of ISGLS and 22 with grade B heptic insufficiency after the second-stage ALPPS. Eighteen patients had grade Ⅰ complications of Clavien-Dindo classification, including 11 with a small pleural effusion, 7 with a small pleural and abdominal effusion; 12 patients had grade Ⅱ complications of Clavien-Dindo classification, including 4 with pneumonia, 4 with coagulation disorders, 3 with massive abdominal effusion, 1 with biliary fistula; 3 patients had grade Ⅲ complications of Clavien-Dindo classification, including 1 with pneumothorax and pneumonia, 1 with massive pleural effusion, 1 with obstructive jaundice; 1 patient had grade Ⅳ complications of Clavien-Dindo classification as pneumonia and anemia. All patients with complications were improved after symptomatic treatment, anti infection, transfusion of fresh frozen plasma or drainage. (3) Follow-up: 40 patients were followed up for 2-35 months, with a median follow-up time of 17 months. The 6-month, 1-, and 2-year survival cases were 35, 26, 21 cases. Conclusion:Three-dimensional visualization technology can clearly show the MHV classification and its relationship with tumor location, which has an important guiding significance in the decision-making of MHV management in ALPPS.