Distributed Saturated Control for a Class of Semilinear PDE Systems: A SOS Approach

Producción CientíficaThis paper presents a systematic approach to deal with the saturated control of a class of distributed parameter systems which can be modeled by first-order hyperbolic partial differential equations (PDE). The approach extends (also improves over) the existing fuzzy Takagi-Sugeno (TS) state feedback designs for such systems by applying the concepts of the polynomial sum-of-squares (SOS) techniques. Firstly, a fuzzy-polynomial model via Taylor series is used to model the semilinear hyperbolic PDE system. Secondly, the closed-loop exponential stability of the fuzzy-PDE system is studied through the Lyapunov theory. This allows to derive a design methodology in which a more complex fuzzy state-feedback control is designed in terms of a set of SOS constraints, able to be numerically computed via semidefinite programming. Finally, the proposed approach is tested in simulation with the standard example of a nonisothermal plug-flow reactor (PFR).The research leading to these results has received funding from the European Union and from the Spanish Government (MINECO/FEDER DPI2015-70975-P)

Detection of mutations in exons 5-8 of the P53 gene in gastric cancer samples using PCR-SSCP in Chaharmahal va Bakhtiari province 2006-2007

زمینه و هدف: سرطان معده دومین سرطان شایع در جهان است. فاکتورهای ژنتیکی مانند انکوژن ها و ژن های سرکوبگر تومور، همواره از جمله مهمترین عوامل در بروز این سرطان هستند. ژن P53 یک ژن سرکوبگر تومور است و نقش بسیار مهمی در فرآیند مرگ برنامه ریزی شده سلول ایفا می کند. جهش در ژن P53 موجب از بین رفتن عملکرد محافظتی آن شده که یکی ازعوامل اصلی بروز سرطان معده در انسان است. این مطالعه با هدف بررسی جهش های ژن P53 در بیماران مبتلا به سرطان معده در استان چهارمحال و بختیاری انجام شده است. روش بررسی: در این مطالعه توصیفی آزمایشگاهی به بررسی جهش ها در اگزون های شماره 8-5 ژن P53 در 38 نمونه پارافینه سرطان معده پرداخته ایم. ابتدا DNA به روش استاندارد فنل کلروفرم استخراج شد، سپس با استفاده از تکنیک PCR-SSCP جهش های این ژن بررسی شدند. یافته ها: تفاوت های آشکاری در همه نمونه های کنترل مثبت مشاهده شد. با این وجود در سایر نمونه های مربوط به بیماران هیچ تفاوت و تغییری در حرکت باندها تشخیص داده نشد. نتیجه گیری: در استان چهارمحال و بختیاری ارتباط بین سرطان معده با جهش های ژن P53 بسیار ضعیف است. البته این مطالعه فقط بر روی 38 نمونه بیمار انجام شده و مطالعات بیشتری نیاز است تا ارتباط واقعی جهش بر روی ژن P53 با سرطان معده در این استان مشخص شود

Comparison between the cultures of human induced pluripotent stem cells (hiPSCs) on feeder- and serum-free system (Matrigel matrix), MEF and HDF feeder cell lines

Human induced pluripotent stem cells (hiPSCs) are a type of pluripotent stem cells artificially derived from an adult somatic cell (typically human fibroblast) by forced expression of specific genes. In recent years, different feeders like inactivated mouse embryonic fibroblasts (MEFs), human dermal fibroblasts (HDFs), and feeder free system have commonly been used for supporting the culture of stem cells in undifferentiated state. In the present work, the culture of hiPSCs and their characterizations on BD Matrigel (feeder- and serum-free system), MEF and HDF feeders using cell culture methods and molecular techniques were evaluated and compared. The isolated HDFs from foreskin samples were reprogrammed to hiPSCs using gene delivery system. Then, the pluripotency ability of hiPSCs cultured on each layer was determined by teratoma formation and immunohistochemical staining. After EBs generation the expression level of three germ layers genes were evaluated by Q-real-time PCR. Also, the cytogenetic stability of hiPSCs cultured on each condition was analyzed by karyotyping and comet assay. Then, the presence of pluripotency antigens were confirmed by Immunocytochemistry (ICC) test and alkaline phosphatase staining. This study were showed culturing of hiPSCs on BD Matrigel, MEF and HDF feeders had normal morphology and could maintain in undifferentiated state for prolonged expansion. The hiPSCs cultured in each system had normal karyotype without any chromosomal abnormalities and the DNA lesions were not observed by comet assay. Moreover, upregulation in three germ layers genes in cultured hiPSCs on each layer (same to ESCs) compare to normal HDFs were observed (p<0.05). The findings of the present work were showed in stem cells culturing especially hiPSCs both MEF and HDF feeders as well as feeder free system like Matrigel are proper despite benefits and disadvantages. Although, MEFs is suitable for supporting of stem cell culturing but it can animal pathogens transferring and inducing immune response. Furthermore, HDFs have homologous source with hiPSCs and can be used as feeder instead of MEF but in therapeutic approaches the cells contamination is a problem. So, this study were suggested feeder free culturing of hiPSCs on Matrigel in supplemented media (without using MEF conditioned medium) resolves these problems and could prepare easy applications of hiPSCs in therapeutic approaches of regenerative medicine such as stem-cell therapy and somatic cell nuclear in further researches

Study of two common P53 gene mutations in gastric cancer using PCR-RFLP in Chaharmahal va Bakhtiari province, Iran, 2003

Background and aim: Gastric cancer is the most common cause of cancer death world wide after lung cancer. Genetic factors including oncogenes and tumor suppressor genes are always involved in progression of this cancer. The P53 tumor suppressor gene is believed to have a broad role in the cell such as programmed cell death and stop cell replicating damaged DNA which has been summarized as the guardian of the genome. This study aims to determine the frequency of two common P53 gene mutations using PCR-RFLP in gastric cancer in Chaharmahal va Bakhtiari province. Methods: This descriptive – lab based study describes the mutation analysis of paraffin embedded gastric samples from 38 patients in Chaharmahal va Bakhtiari province. We have investigated the frequency of P53 gene mutation in exons 7 and 8 by PCR-RFLP to detect alteration in two common hot spots in codon 248 and 282. Results: We determined no mutation in P53 gene hot spots in codon 248 and 282. Conclusion: We conclude that association of P53 gene mutations with gastric cancer is very low in Chaharmahal va Bakhtiari province. However we have examined only 38 gastric samples and more samples need to be investigated to reveal the contribution of P53 gene mutation in causing gastric cancer in this province. Also it is necessary to study the entire coding region and promoter of the gene in patients from different population and ethnic groups

Artificial Intelligence Aided Adaptive Control Strategies for Converter Based Power Systems

European Union (EU) has set targets to reduce greenhouse gas emissions by at least 55% (compared to 1990 levels) by 2030. EU aims to become climate-neutral by 2050, with the exception of Denmark, which has set an even more ambitious goal of achieving climate neutrality by 2045. In the coming years, one of the inevitable efforts to achieve these targets is the expansion of Renewable Energy Source (RES) such as wind turbines and PhotoVoltaic (PV) in the electrical power grid. Smart AFE converters play a crucial role as the key interface components connecting RESs to the grid. Increasing the number of RESs results in small-signal stability issues, especially in cases where the RES is connected to a weak grid.In certain cases, stability challenges arise from variations in grid conditions, such as changes in grid impedance. To enhance system reliability and performance, it is essential to adapt the control parameters to the new grid conditions. This thesis presents a novel method for the active identification and adaptive tuning of multiple control parameters using ANNs. The proposed method utilizes the EKF algorithm to identify the grid parameters. These identified parameters are subsequently utilized in an ANN-based parameter searching algorithm. This algorithm ensures pole-tracking-based stabilization by determining the optimal solution for the PI control parameters. The main innovation of this method lies in its capability to perform online tuning of multiple control parameters in AFEs. To validate the effectiveness and performance of the proposed approach, a comprehensive evaluation is conducted, consisting both simulation results and experimental tests conducted at PowerLabDK. The results demonstrate the effective and adaptive stabilization capability of the proposed method in the presence of varying grid impedance.The active (intrusive) identification method, due to the injected disturbance, may temporarily degrade the performance of the converter. Moreover, when the amplitude of the injected disturbance is large, it can potentially activate nonlinearity in the system’s behavior. This thesis proposes an online method to address these issues by tuning the parameters of the model predictive controller for AFE using a passive identification algorithm. In the proposed method, the grid is represented by a state space structure. The incorporation of augmented state variables, besides the system parameters, yields a dynamic state-space model characterized by nonlinearity. The EKF is utilized in this research to observe the state variables and identify the system parameters. While the concepts of the EKF and MPC are employed to control the AFE system, the algorithm’s performance relies on the selection of appropriate weighting factors. To determine the optimal weighting factors, an innovative algorithm based on ANN is developed. This ANN-based algorithm is specifically designed to identify the optimal weighting factor from a predefined set of options, taking into account the unique characteristics of the grid at each iteration. An offline Particle Swarm Optimization (PSO) algorithm is executed to generate the required data for the predefined set of weighting factors options. The proposed method offers several advantages, which can be enumerated as follows: identification of grid impedance and inductance, guaranteeing hard constraints on the amplitude of input and output variables, enhancing the performance of CCS MPC through parameter updates in each iteration, and increasing the prediction horizon. The proposed method was implemented experimentally in PowerLabDK, and the results of the experiment demonstrate that the algorithm effectively stabilizes the grid-tied converter in weak grid conditions, even when facing significant changes in grid impedance.In addition to addressing stabilization concerns, the converters have the capability to improve grid performance. Another challenge in grid-tied converters involves unbalanced conditions, which can result in power losses and power quality issues. This thesis also presents an IoT-based reference generator for voltage unbalanced compensation. The proposed method takes into account the challenges coming from packet losses and time delays. The measured current and voltage data taken at the remote transformer are transmitted to the edge devices through the cloud interface. The edge device controller compares the measured data from the transformer with the reference data to generate an appropriate reference signal for the converter. However, there are two primary challenges associated with cloud-based control: packet losses and delays in response time. This thesis introduces a novel sampled-data secondary controller, designed to be robust against packet losses and time delays, implemented in edge devices. The Intelligent Redesign (IRD) method aims to convert a pre-designed analog controller into its equivalent digital counterpart. The method establishes sufficient conditions, expressed in terms of Linear Matrix Inequality (LMI), to ensure both the stability of the closed-loop digital system and the minimization of errors. The secondary controller is designed by solving the LMI conditions. To assess the applicability and efficiency of the proposed approach, the method is experimentally implemented in PowerLabDK