[Emission Characteristics and Emission Factors of Volatile Organic Compounds from E-waste Dismantling and Recycling Processes]

A large number of volatile organic compounds (VOCs) are emitted from the high temperature treatment process in the dismantling and recycling procedure of e-wastes, which has a significant impact on the surrounding environment and human health. In this study, an e-waste dismantling and recycling yard was selected to measure the VOCs concentrations and compositions in the exhaust of treatment facilities of heating baking board, plastic granulation, wet extraction, and pyrometallurgical workshops, and the emission characteristics of VOCs and emission factors for total VOCs from different production processes were investigated. The results showed that there were significant differences in total VOCs emission concentrations among different production processes. The concentrations of total VOCs produced in different workshops followed the descending order of the heating baking board (heating rotary plate furnace) process[(2096.1±732.4) μg·m^-3] > plastic granulation process[(1639.1±538.5) μg·m^-3] > heating baking board (electric heater) process[(625.3±535.5) μg·m^-3] > pyrometallurgical process[(436.8±305.2) μg·m^-3] > wet extraction process[(271.3±73.1) μg·m^-3]. The compositions of VOCs emitted from different production processes were also clearly different; however, the major components of VOCs were generally oxygenated compounds and aromatic hydrocarbons. The specific component characteristics were as follows:the dominant groups of VOCs emitted from the heating baking board process (including heating rotary plate furnaces and electric heaters) were oxygenated compounds and aromatic hydrocarbons, accounting for 74.1%-79.7% of the total. The main components of VOCs emitted from the pelletizing process were aromatic hydrocarbons and oxygenated compounds, accounting for 71.8% of the total. Oxygenated compounds and aromatic hydrocarbons, which contributed equally, were also the main groups of VOCs discharged by the wet extraction process, and the sum proportion of the two groups was 84.2%. Halogenated hydrocarbon was the dominant group of VOCs from the pyrometallurgical process, accounting for 92.1% of the sum of VOCs. There was a substantial divergence in the total VOCs emission factors of different production processes. The ranking of the mean values of emission factors of total VOCs was as follows:the heating baking board (electric heater) process (297.0 g·t^-1) > plastic granulation process (29.5 g·t^-1) > wet extraction process (25.4 g·t^-1) > heating baking board (heating rotary plate furnace) process (25.2 g·t^-1) > pyrometallurgical process (1.9 g·t^-1). Therefore, the main VOCs emission processes of the e-waste centralized dismantling and recycling industry were the heating baking board process and plastic granulation process.

[Robotic versus laparoscopic total mesorectal excision with partial preservation of Denonvilliers fascia: a comparative study of short-term efficacy and urinary and erectile function]

Objective: Postoperative sexual and urinary dysfunctions are common in rectal cancer patients. This study was conducted to compare the short-term efficacy and the impact of surgery on urinary and erectile functions between laparoscopy and robotic-assisted total mesorectal excision (TME) with partial preservation of Denonvilliers fascia. Methods: A retrospective cohort study was carried out. Clinical data of 276 patients with low rectal cancer who underwent TME with partial preservation of Denonvilliers fascia in our department between January 2016 and March 2019, including 143 in robotic group and 133 in laparoscopic group, were analyzed. All the patients were positioned by rigid rectoscope, and the distance between the tumor and the anal verge was ≤7 cm. The urinary and erectile functions were followed up at postoperative 12-month and evaluated by IPSS score (0-7 points as mild symptoms, 8-19 points as moderate symptoms, 20-35 points as severe symptoms; the excellent rate was defined as the rate of mild symptoms) and IIEF-5 score (score ≥ 22 as no dysfunction, 12-21 as mild, 8-11 as moderate, and 5-7 as severe) respectively. Results: There were no significant differences in operation ways between the two groups (P>0.05). The operation time of the robotic group was longer than that of the laparoscopic group [(312.5±75.4) minutes vs. (273.9±65.6) minutes, t=4.514, P<0.001]. However, in patients with higher body mass index (BMI ≥25 kg/m(2)), there was no significant difference in operation time between the two groups [(309.3±78.5) minutes vs. (276.1±75.3) minutes, t=1.751, P=0.085]. The time to postoperative flatus [(1.3±0.4) days vs. (1.5±1.0) days, t=-2.037, P=0.046], defecation [1 (1-5) days vs. 1 (1-12) days, Z=-2.209, P=0.008] and liquid diet [(1.0±0.1) days vs. (1.2±0.1) days, t=3.195, P=0.002] in the robotic group were all shorter than those in the laparoscopic group. While postoperative length of hospital stay in the robotic group was longer than that in the laparoscopic group [(8.5±5.5) days vs. (7.2±3.3) days, t=2.419, P=0.016]. There were no significant differences between the two groups in intraoperative blood loss, conversion rate, morbidity of postoperative complications, positive rate of distal resection margin, positive rate of circumferential resection margin, and the number of resected lymph nodes (all P>0.05). At postoperative 12 months, none of the robotic group nor the laparoscopic group had severe urinary dysfunction, and the overall excellent rate of urinary function reached 97.6% (83/85) and 98.4% (61/62) respectively. The rate of normal and mild erectile dysfunction in the robotic group and the laparoscopic group were 92.2% (47/51) and 92.6% (38/41) respectively (P>0.05). There was no significant difference between the two groups was found regarding the urinary and erectile function (both P>0.05). Conclusions: Compared with laparoscopic, the robotic TME with partial preservation of Denonvilliers fascia has no significant differences in surgical safety and short-term efficacy. They have similar advantages in the protection of urinary and erectile function. Meanwhile the robotic surgery presents faster postoperative recovery of gastrointestinal function.