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BackgroundPer- and poly-fluoroalkyl substances (PFAS) are a class of emerging persistent organic pollutants, and their negative health impacts have been widely concerned. There is a lack of epidemiological studies on the associations of PFAS exposure with lipid homeostasis. ObjectiveTo investigate the associations of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) exposure with blood lipid levels and dyslipidemia in middle-aged and elderly women. MethodsThis study was based on 795 middle-aged and elderly women from a female sub-cohort of the Dongfeng-Tongji cohort study, excluding the participants without blood lipid measurements and/or reported use of lipid-lowering drugs at baseline. The concentrations of plasma PFOS and PFOA were measured by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The concentrations of serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured using an automatic analyzer. The normally distributed continuous variables were presented as mean ± standard deviation (\begin{document}$ \bar{x}\pm s) $\end{document}, while the skewedly distributed continuous variables were presented as median (M) and the 25th and 75th percentiles (P25, P75). Generalized linear models (GLM), generalized additive models (GAM), and logistic regression models were applied to evaluate the associations of PFOS and PFOA exposure with blood lipid levels and the risk of dyslipidemia. Stratified analyses were also implemented to explore potential modification effects of sociodemographic characteristics, lifestyles, and menopause on associations of PFOS and PFOA exposure and blood lipids. ResultsThe \begin{document}$ \bar{x}\pm s $\end{document} of baseline age for the study participants was (59.4±8.6) years old, and their baseline body mass index (BMI) was (24.3±3.4) kg·m−2. The M (P25, P75) of baseline plasma concentrations for PFOS and PFOA were 9.96 (6.24, 15.09) μg·L−1 and 1.20 (0.84, 1.80) μg·L−1 respectively. The GLM analysis showed that plasma concentration of PFOS was positively associated with serum HDL-C [b (95%CI): 0.04 (0.01, 0.07)]. The plasma concentration of PFOA was also positively associated with serum TC [b (95%CI): 0.05 (0.02, 0.08)] and serum LDL-C [b (95%CI): 0.05 (0.01, 0.09)]. No significant association was observed between plasma PFOS and serum TC, TG, or LDL-C, nor between plasma PFOA and serum TG or HDL-C. The stratified analyses showed that the association between PFOA and LDL-C was significant among the participants aged

In view of energy waste and environmental pollution in the process of ship navigation, a triple low temperature heat source for heating system is presented. It considers the advantages of solar energy heat pump and water source heat pump and waste heat utilization. This system can make high-quality heat by using the solar radiation, seawater and residual heat in marine cylinder liner cooling water. It can change the operation mode by valve switching according to the different weather conditions. The heating mode was different in different time. For Dalian area as an example, it gives out the collector outlet temperature curve by computer simulation. And it shows that the combined heat source can increase the heating coefficient by 1.03. It solves the problem of single application of solar energy or water source heat pump, making full use of the waste heat, so it is feasible for dynamic selection of ship heating mode. [ABSTRACT FROM AUTHOR]

This paper presents an improved adaptive simulated annealing genetic algorithms of optimal sensor placement (OSP) based on Modal Assurance Criterion (MAC). Taking the maximum off-diagonal element of the MAC matrix as a target function and the sensor number as a constraint condition, a dualistic coding genetic algorithm is developed which improve the traditional simulation annealing algorithms and use it as an independent operator of GA. Therefore, adaptive crossover and mutation probabilities are adopted to prevent premature convergence. Example results clearly indicate that the method is feasible in optimal sensor placement and number selection, and optimal placement for different accuracy requirement is obtained. [ABSTRACT FROM AUTHOR]

The time-control drilling technology had been used for saving the cost of drilling, shortening the construction period and reducing the risks of drilling in the process of coring and layer determination of a coalbed methane well in Jixi Basin of Heilongjiang Province. The method identified the target layer's which was characterized by combination of thin seams, controlling the speed of drilling and footage and the application of careful cut logging method, and finally coring successfully. The results showed that this technology which reduced the workload of coal drilling without coal core, saved the cost of drilling, shortened the period of drilling engineering construction and increased the efficiency of drilling, the technology was an effective method for sticking bed in coalbed methane well. [ABSTRACT FROM AUTHOR]

The small Qubit quantum algorithm attack to RSA was proposed,the need Qubit of the first quantum register from 2L to L1,it can be reduced to 2 Qubit,the overall space complexity denoted (L1,L),where 2L1≥r,r is the period of decomposed.Because of the reduce of the first quantum register,it reduces the algorithm’s complexity and success rates,and use the binary look-up table method to compute the modular exponentiation,it enhances the computing speed.The improved algorithm’s quantum circuit complexity is T=O(2L2).It have a significant improvement on the time complexity and space complexity.Although the success rate is reduced,the overall success solution time is still lower than the Shor algorithm and the current major improvements Shor algorithm.Completed a simulation experiment.Respectively use the 11、10、9 Qubit decomposing the quantum circuit 119.The new algorithm explore the reality of using a universal quantum computer device to decipher the public key cryptography.

Objective: This study explores the application of gastric tube interposition by touching laryngeal prominence in postoperative oral cancer patients., Methods: This trial includes 66 patients treated in the West China Hospital of Stomatology from August 2014 to December 2014. These patients were randomly divided into two groups: the test group included 33 patients who underwent gastric tube interposition by touching laryngeal prominence; the 33 other patients, who served as control group, underwent regular gastric tube interposition. The two groups were compared in terms of the occurrence rate of bucking, success rate of one-time gastric tube placement, and interposition time., Results: Compared with those in the control group, the occurrence rate of bucking and the interposition time in the test group decreased while the success rate of one-time gastric tube placement increased (P<0.05)., Conclusions: Gastric tube interposition by touching laryngeal prominence can improve the success rate of one-time gastric tube interposition; moreover, it can reduce the average interposition time and the pain experienced by patients.

Purpose: To evaluate the change of stress distribution after bonding and replantation of vertical fractured first maxillary premolar., Methods: The stress distribution in two types of loading and different treatments on the vertical fractured first maxillary premolar were analyzed by three dimensional finite element. The gap was respectively filled with Clearfil SE Bond and Super Bond C & B; and vertical and lateral stress force was calculated., Results: The result of the FEM study of adhesive fracture tooth indicated that the stress distribution was similar to the normal tooth, Clearfil SE Bond was better than Super Bond C & B., Conclusion: The treatment of bonding and replantation for vertical fractured tooth is effective.

Objective: To analyse the stress variations of root canal wall that resulted from vertical and lateral condensation., Methods: On the basis of the finite-element model of the mandibular first molar that modified by step-back technique, mesial-buccal root canal was chosen as tested root canal and simulated the procedure of vertical and lateral condensation. The maximal stress of root canal wall and its position were calculated by special software upon different loading condition., Results: Stress of root canal wall caused by vertical condensation was higher than that by lateral condensation on the same loading condition. Maximal stress of vertical condensation was located on loading section and one of lateral condensation was located on coronal and middle 1/3 of root. The lower the position that was loaded, the higher the stress of wall of root canal., Conclusion: Lateral condensation will not bring on vertical root fracture directly,but over-force and improper operation are both dangerous that gives rise to vertical root fracture with whichever method.

Objective: To analyze the stress variations of wall of root canal of pulpless teeth that resulted from different diameters of root canal., Methods: On the basis of the finite-element model of the mandibular first molar that modified by routine, diameter of root canal was modified and enlarged so as to the diameter of root canal was 1/3 and 1/2 of root diameter, then modified models were loaded and the maximal stress of each part of teeth and wall of root canal was calculated., Results: The results revealed that enlargement of root canal diameter will bring on increase of stress of root canal wall at the orifice and coronal 1/3. The stress difference of lateral loading was greater than that of vertical loading., Conclusion: The principle of root canal preparation should be infected material removed and good shape of root canal gained. Over-preparation is unnecessary and harmful.

Objective: To evaluate the stress influence in different contour of class II cavity with different filling materials on first maxillary premolar., Methods: The stress distribution in two types and all three contours of class II cavity in maxillary premolar were analyzed by three dimensional finite element. The cavity was respectively filled with amalgam and composite resin; and the vertical and lateral stress force was calculated., Results: In the different contours, the stress of composite restoration by slot design was close to that by dovetail design, and the stress of amalgam restoration by slot design, especially in vertical force, descended respectively at 41%,29% and 27%., Conclusion: When class II lesions is only limited in proximal region of the premolar, the filling of composite resin with slot design is recommended.

Objective: Use FEM to observe the relationship between the change of alveolar ridge's height and the stress change of wall of root canal., Methods: Modify the model on the basis of the set up model of the mandibular first molar, simulating the height of alveolar ridge and reducing 1/4, 1/3, 1/2 of the height to set up modified model, and load on the modified model by vertical and lateral forces. Then calculate the maximum mises stress of each part of teeth and wall of root canal., Results: The stress-changing tendency of each part of wall was similar to the changing tendency of each part of teeth, but the stress of wall was fewer than the stress of teeth. The stress value of original model was close to the modified model at the orifice. Then the stress of original model obviously reduced, and the stress of the modified model reached maximum in the coronal thirds, and when the fixed height was lower, the stress was larger, the stress reduced more slowly. The lateral stress was larger than the vertical stress, and when the fixed height was lower, the difference was more obvious., Conclusion: The change of alveolar ridge's height will affect the stress change of wall of root canal, and which is in an inverse proportion.

Objective: To analyze the stress variations of the root canal wall of pulpless tooth by different root canal preparations., Methods: On the basis of the set up model of the mandibular first molar, modified model was established by simulation of the routine or step-back root canal preparation and filling in. Then the maximum mises stress of each part of teeth and wall of root canal were calculated by special finite-element software., Results: The stress-changing tendency is similar between two modified models but the maximum mises stress of the model by step-back technique is a little greater than one by routine. The stress of wall of mesial-buccal root canal was the greatest and one of mesial-lingual root canal was the least at three root canals. The stress-changing tendency of modified models was similar to original model. The maximum mises stress of modified models was near or less than one of original model except that of amalgam layer because of material property alteration., Conclusion: Not only routine but step-back technique is an effective and safe method. Dentist can choose them in practice.