Dioxins were a family of chlorinated aromatic hydrocarbons mainly coming from combustion process with the presence of a chlorine donor and the chlorine-treatment process in chemical industries. Dioxins had been proved to be one of the most toxic materials in environment in recent studies ,and to present carcinogenesis ,teratogenesis ,immunotoxicity,reproductive toxicity and endocrine toxicity ect. With the development of the industrialization ,the dioxins pollution tended to become more and more serious ,which had severely threatened human health. This paper presented a review on the molecular structure,physicochemical characteristics ,pollution sources and degradation ways in environment and impacts of dioxins on human health.

Objective To investigate the diagnostic value of Astograph methacholine provocation test in patients with chest tightness variant asthma ( CTVA)??Methods From January 2011 to February 2017,156 patients with CTVA in outpatient or inpatient department of respiratory medicine of Kailuan General Hospital affiliated to North China University of Science and Technology were selected as case group ( chest tightness variant asthma group )??The control group were 361 non?asthmatic patients including interstitial lung disease ( 23 cases), coronary disease ( 157 cases), hypertensive cardiopathy ( 22 cases), myocardiosis (16 cases),congenital heart disease ( 3 cases),rheumatic valvular heart disease (6 cases), central airway disease (3 cases),thyromegaly (10 cases),mediastinal tumor (5 cases),thoracic or spinal deformity (8 cases),phrenoparalysis (2 cases) and vegetative nerve functional disturbance (106 cases)??All participants received pulmonay ventilation test, average daily and nightly variation rate of PEF ( Peak expiratory flow) or PEF weekly variability, Astograph methacholine provocation test ( forced expirataory volume in one second≥70% expectation),and other relevant examinations??The diagnostic value of Astograph methacholine provocation test on CTVA was assessed by analyzing the sensitivity, specificity, positive predictive value,negative predictive value,and Yunden index of Astograph methacholine airway??Results Compared with the control group (( 1??18 ± 0??44)%), theforced expiratory flow from 75% of Forced vital capcacity ( FEF75 ) index of CTVA group (( 1??29 ± 0??50 )%) had significant difference (, t＝ 2??96, P＝0??006)??The sensitivity,specificity,positive predictive value,negative predictive value,Yunden index,and diagnostic accuracy of Astograph methacholine provocation test on CTVA were 0??814,0??695,0??536,0??305, 0??509 and 0??731, respectively??Conclusion The sensitivity, negative predictive value, Yunden index and diagnostic accuracy of Astograph methacholine provocation test on CTVA were higher,whereas the specificity and positive predictive value were relatively lower,suggesting that Astograph methacholine provocation test had a reliable diagnostic value on CTVA,with lower false negative and higher false positive??

Objective:To retrospectively analyze the clinical efficacy and safety of three-dimensional radiotherapy for the primary tumors in patients with stage Ⅳ non-small cell lung cancer complicated with malignant pleural effusion (MPE-NSCLC).Methods:A total of 198 patients who were initially pathologically diagnosed with MPE-NSCLC from January 2007 to April 2018 were enrolled and divided into the untreated group ( n=45), drug group ( n=57) and radiotherapy group ( n=96), respectively. The short-term efficacy, overall survival (OS) and adverse events in the drug and radiotherapy groups were analyzed. The OS rate was analyzed by Kaplan-Meier method and log-rank test. Clinical prognosis was evaluated by multivariate Cox′s regression model. Results:In the radiotherapy group, the objective response rate and non-response rate was 54% and 46%, significantly better than 25% and 75% in the drug group ( P=0.007). In the radiotherapy group, the 1-, 2-, 3-, 5-year OS and median survival was 47%, 18%, 6%, 1% and 12 months, remarkably higher than 15%, 3%, 2%, 0% and 5 months in the drug group, respectively (all P<0.001). Multivariate Cox′s regression analysis showed that radiotherapy for the primary tumors was an independent prognostic factor to prolong the OS ( P<0.001). Radiotherapy at a dose of ≥63 Gy and 4-6 cycles of chemotherapy tended to prolong the OS ( P=0.063 and 0.071). The OS of patients with EGFR mutation receiving radiotherapy combined with molecular target therapy was significantly better than that of those with unknown EGFR status treated with radiotherapy and chemotherapy ( P=0.007). Addition of radiotherapy for the primary tumors did not significantly increase the incidence of adverse events ( P>0.05). Conclusion:Addition of three-dimensional radiotherapy for the primary tumors in MPE-NSCLC patients may prolong the OS and yield tolerable adverse events.

Objective: To investigate the changes of internal fixation stress under different angles of interior fracture line and different screw placement modes in the case of A-type distal femoral fracture. Methods: A 24-year-old healthy male volunteer was recruited to collect the right femur data. CATIA V5R21 software produced a 10 mm fracture gap at the external side of the femur 6.5 cm proximal to the joint line and different angle fracture lines were generated on the internal of the femur at the same height. Based on the actual measured dimensions, the three-dimensional (3D) model of the locking plate and screw was reconstructed using CATIA V5R21 software, ignoring the screw surface threads and then the assembly of the internal fixation of the titanium plate, screws and femur was done. All models were meshed using Hypermesh 13.0 software. The assembled 3D model was input into ABAQUS 6.14 to generate a finite element model. Preliminary finite element biomechanical analysis was performed using the four medial fracture line angles and the stress distribution of the internal fixation under the three screw placement modes, and then the analysis was continued after the optimal screw placement method was re-determined. Results: Under an axial loading of 700 N, with the increase of the angle of the fracture line, the stress of the lateral internal fixation gradually increased, and the displacement of the proximal end of the fracture gradually increased. The sequential screw placement method was superior to the leaping screw placement method. The placement of the first screw at the proximal end of the fracture was critical to the distribution of the internal fixation stress. Conclusions The operation plan of the type A of distal femoral fracture needs to be confirmed according to the internal and external fracture′s condition. When the fracture line is at a excessive positive angle or a negative angle, a simple lateral fixation may not provide a stable fracture fixation so that other fixation methods are needed.