Improved PI controller based on predictive functional control for liquid level regulation in a coke fractionation tower

Due to limitations of hardware, cost and so on, the application of proportional-integral-derivative (PID) control is more convenient than predictive control. However, predictive control usually has better performance than traditional PID control, thus it is important to combine the advantages of these two control algorithms. A novel PI controller optimized by predictive functional control (PFC) is proposed and tested on liquid level in the industrial coke fractionation tower in this paper. Since this kind of process always shows the integrating behavior, a P controller is first used for it to generate a self-balancing generalized process, then the PFC based PI control is designed for the generalized process. The resulting controller displays the performance of both PFC and PI control with easy implementation in practice. The performance of the proposed PI controller is compared with traditional PI controller in terms of regulatory/servo setpoint tracking, disturbance rejection and measurement noise issues, from which results show that the proposed PI controller provides better performance than traditional PI controller. (C) 2014 Elsevier Ltd. All rights reserved

Improved state space model predictive fault-tolerant control for injection molding batch processes with partial actuator faults using GA optimization

A novel model predictive fault-tolerant control (MPFTC) strategy adopting genetic algorithm (GA) is proposed for batch processes under the case of disturbances and partial actuator faults. Based on the extended state space model in which the tracking error is contained, there are more degrees of freedom provided for the controller design and better control performance is obtained. In order to enhance the control performance further, the GA is introduced to optimize the relevant weighting matrices in the cost function. The effectiveness of the proposed MPFTC approach is tested on the injection velocity regulation of the injection molding process.</p

Predictive control optimization based PID control for temperature in an industrial surfactant reactor

Due to the character of nonlinearity, uncertainties, time delays and so on in the industrial reactors, the performance of proportional-integral-derivative (PID) control cannot always achieve the desired effect. Model predictive control (MPC) is a useful control strategy in the fact that the process models do not need to be accurately known. However, limited by the cost, hardware and so on, the application of MPC is less convenient than PID. In this paper, the temperature control in an industrial surfactant reactor is studied, where an improved PID controller optimized by extended non-minimal state space model predictive control (ENMSSMPC) framework is employed. The temperature in the surfactant reactor is first modeled as a typical step-response model and then a corresponding improved state space transformation with subsequent MPC design is done. The overall strategy combines the advantages of both PID's simple structure and MPC's good control performance. The proposed method is compared with traditional PID and MPC controllers and results show that it provides improved performance. © 2014 Elsevier B.V

Waist circumference increases risk of coronary heart disease: Evidence from a Mendelian randomization study

Abstract Background This study investigated whether expanding waist circumference (WC) is causally associated with an elevated risk of coronary heart disease (CHD), using a two‐sample Mendelian randomization (MR) study through integrating summarized data from genome‐wide association study. Methods The data included in this analysis were mainly from the Genetic Investigation of ANthropometric Traits (GIANT), Consortium and Coronary Artery Disease Genome wide Replication, and Meta‐analysis plus the Coronary Artery Disease (C4D) Genetics (CARDIoGRAMplusC4D) Consortium. Three statistical approaches, inverse‐variance weighted (IVW), weighted median, and MR‐Egger regression method were conducted to assess the casual relationship. The exposure was WC, measured by 46 single‐nucleotide polymorphisms from GIANT and the outcome was the risk of CHD. Then, we used the genetic data from Neale Lab and TAG to infer whether WC causally affected the established risk factors of CHD. Results The IVW method presented that genetically predicted WC was positively casually associated with CHD (odds ratio [OR]: 1.57, 95% CI = 1.33–1.84; p = 4.81e‐08), which was consistent with the result of weighted median and MR‐Egger regression. MR‐Egger regression indicated that there was no directional horizontal pleiotropy to violate the MR assumption. Additionally, expanded WC was also associated with higher risk of hypertension and diabetes, higher cholesterol, more smoking intensity, and decreased frequency of physical activity. Conclusion Our analysis provided strong evidence to indicate a causal relationship between WC and increased risk of CHD

MicroRNA-497 Induces Apoptosis and Suppresses Proliferation via the Bcl-2/Bax-Caspase9-Caspase3 Pathway and Cyclin D2 Protein in HUVECs

<div><p>Introduction</p><p>MicroRNAs play crucial roles in various types of diseases. However, to date, no information about the role of miR-497 in the development of atherosclerosis has been reported. This study investigated the possible role of miR-497 in vascular endothelial cell injury during the early stage of atherosclerosis.</p><p>Materials and Methods</p><p>The expression level of miR-497 in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL was detected using qRT-PCR. To perform gain of function and loss of function analyses, miR-497 mimics were transfected into HUVECs, and miR-497 inhibitors were transfected into HUVECs stimulated with ox-LDL. Flow cytometry was used to analyze cell cycle progression and apoptosis. EdU and CCK-8 assays were employed to detect DNA synthesis and cell proliferation, respectively. After bioinformatics prediction, a dual Luciferase Reporter assay was used to analyze the direct target genes of miR-497. The mRNA and protein levels of the target genes were detected using qRT-PCR and western blot analyses, respectively. Caspase-9/3 activity was analyzed to determine the mechanism of endothelial dysfunction.</p><p>Results</p><p>We showed that miR-497 was significantly upregulated in HUVECs stimulated with ox-LDL. Ectopic expression of miR-497 suppressed cell proliferation, induced apoptosis and increased the activity of caspase-9/3. After verification, Bcl2 and CCND2 were shown to be direct target genes of miR-497 in HUVECs. MiR-497 significantly suppressed cell proliferation by arresting the cell cycle through the CCND2 protein and induced apoptosis through the Bcl2/Bax-caspase9-caspase3 pathway.</p><p>Conclusion</p><p>Overall, our study shows that miR-497 might play a role in the development of atherosclerosis by inducing apoptosis and suppressing the proliferation of vascular endothelial cells. Therefore, miR-497 could be a potential therapeutic target for the treatment of atherosclerosis.</p></div

QRT-PCR analysis was used to analyze the levels of miR-497 in HUVECs stimulated with ox-LDL.

<p>HUVECs were exposed to 100 μg/ml ox-LDL for 3, 6, 12, 24, 36, or 48 h. The miR-497 levels were significantly upregulated after 36 h of stimulation with 100 μg/ml ox-LDL; **P<0.01.</p

The effects of the overexpression of miR-497 on the proliferation and apoptosis of HUVECs.

<p>(A) One representative cell cycle profile of HUVECs detected using a flow cytometer. The cells were stained with PI prior to detection. The overexpression of miR-497 reduced the percentage of cells in the S phase. (B) Representative profiles from the EdU cell proliferation assay after transfection with miR-497 for 48 h (magnification 200×). (E) Amount of EdU-positive cells in the different treatment groups. Increased miR-497 expression inhibited cellular DNA replication in HUVECs. (C) Apoptotic status after transfection, as detected by FCM after Annexin V-FITC/PI labeling. (F) Comparison of apoptotic cells in various groups. The percentage of early apoptotic cells was significantly higher in the experimental group. (D) CCK-8 cell proliferation assay for HUVECs. Cell proliferation was significantly inhibited after miR-497 transfection. The data are presented as the mean ± SD. All results are representative of three independent experiments. **P<0.01 versus the control groups.</p