Modeling and Control of Piezoactive Micro and Nano Systems

Piezoelectrically-driven (piezoactive) systems such as nanopositioning platforms, scanning probe microscopes, and nanomechanical cantilever probes are advantageous devices enabling molecular-level imaging, manipulation, and characterization in disciplines ranging from materials science to physics and biology. Such emerging applications require precise modeling, control and manipulation of objects, components and subsystems ranging in sizes from few nanometers to micrometers. This dissertation presents a comprehensive modeling and control framework for piezoactive micro and nano systems utilized in various applications. The development of a precise memory-based hysteresis model for feedforward tracking as well as a Lyapunov-based robust-adaptive controller for feedback tracking control of nanopositioning stages are presented first. Although hysteresis is the most degrading factor in feedforward control, it can be effectively compensated through a robust feedback control design. Moreover, an adaptive controller can enhance the performance of closed-loop system that suffers from parametric uncertainties at high-frequency operations. Comparisons with the widely-used PID controller demonstrate the effectiveness of the proposed controller in tracking of high-frequency trajectories. The proposed controller is then implemented in a laser-free Atomic Force Microscopy (AFM) setup for high-speed and low-cost imaging of surfaces with micrometer and nanometer scale variations. It is demonstrated that the developed AFM is able to produce high-quality images at scanning frequencies up to 30 Hz, where a PID controller is unable to present acceptable results. To improve the control performance of piezoactive nanopositioning stages in tracking of time-varying trajectories with frequent stepped discontinuities, which is a common problem in SPM systems, a supervisory switching controller is designed and integrated with the proposed robust adaptive controller. The controller switches between two control modes, one mode tuned for stepped trajectory tracking and the other one tuned for continuous trajectory tracking. Switching conditions and compatibility conditions of the control inputs in switching instances are derived and analyzed. Experimental implementation of the proposed switching controller indicates significant improvements of control performance in tracking of time-varying discontinuous trajectories for which single-mode controllers yield undesirable results. Distributed-parameters modeling and control of rod-type solid-state actuators are then studied to enable accurate tracking control of piezoactive positioning systems in a wide frequency range including several resonant frequencies of system. Using the extended Hamilton\u27s principle, system partial differential equation of motion and its boundary conditions are derived. Standard vibration analysis techniques are utilized to formulate the truncated finite-mode state-space representation of the system. A new state-space controller is then proposed for asymptotic output tracking control of system. Integration of an optimal state-observer and a Lyapunov-based robust controller are presented and discussed to improve the practicability of the proposed framework. Simulation results demonstrate that distributed-parameters modeling and control is inevitable if ultra-high bandwidth tracking is desired. The last part of the dissertation, discusses new developments in modeling and system identification of piezoelectrically-driven Active Probes as advantageous nanomechanical cantilevers in various applications including tapping mode AFM and biomass sensors. Due to the discontinuous cross-section of Active Probes, a general framework is developed and presented for multiple-mode vibration analysis of system. Application in the precise pico-gram scale mass detection is then presented using frequency-shift method. This approach can benefit the characterization of DNA solutions or other biological species for medical applications

Fast transactive control for frequency regulation in smart grids with demand response and energy storage

This paper proposes a framework for controlling grid frequency by engaging the generation-side and demand-side resources simultaneously, via a fast transactive control approach. First, we use a proportional frequency-price relation to build and analyze a transactive frequency droop controller for a single-area power grid. Then, we develop a transactive demand response system by incorporating a large population of thermostatically controlled air conditioning loads. A proportional-integral controller is used to adjust the setpoint temperature of the air conditioners based on price variations. A battery storage system is then developed and augmented to the system to capture the energy arbitrage effects. A nonlinear price-responsive battery management system is developed to enable effective charging and discharging operations within the battery’s state-of-charge and power constraints. Simulation results indicate that the proposed transactive control system improves the steady-state and transient response of the grid to sudden perturbations in the supply and demand equilibrium. To decouple frequency from price during daily operation and maintain frequency near the nominal value, we propose adding a feedforward price broadcast signal to the control loop based on the net demand measurement. Through various simulations, we conclude that a combination of feedback transactive controller with feedforward price broadcast scheme provides an effective solution for the simultaneous generation-side and demand-side energy management and frequency control in smart power grids

Phenolic Content of Selected Sumac Fruits from Iran, Extracted With Different Solvents

<p>In this study, the phenolic content of three sumac (<em>R. coriaria</em> L.) samples were evaluated including, brown sumac fruit, brown sumac powder and red sumac. Methanol, ethanol, mixture of methanol-ethanol and distilled water were used for extraction. Phenolic content was determined by Folin–Ciocaltaeu procedure. The efficiency of the extraction varied considerably. The phenolic content of brown sumac powder, brown sumac fruit and red sumac powder were 2.906-2.997, 2.438- 2.529, 2.172- 2.263 gallic acid equivalents/100 g (GAE/100 g), respectively. According to the results, ethanol shows the best results and sumac had highest phenolic content as compared to other extracts.</p

The Prognostic Effect of Ethnicity for Gastric and Esophageal Cancer: The Population-Based Experience in British Columbia, Canada

Background: Gastric and esophageal cancers are among the most lethal human malignancies. Their epidemiologyis geographically diverse. This study compares the survival of gastric and esophageal cancer patients amongseveral ethnic groups including Chinese, South Asians, Iranians and Others in British Columbia (BC), Canada.Methods: Data were obtained from the population-based BC Cancer Registry for patients diagnosed with invasiveesophageal and gastric cancer between 1984 and 2006. The ethnicity of patients was estimated according to theirnames and categorized as Chinese, South Asian, Iranian or Other. Cox proportional hazards regression analysis wasused to estimate the effect of ethnicity adjusted for patient sex and age, disease histology, tumor location, diseasestage and treatment.Results: The survival of gastric cancer patients was significantly different among ethnic groups. Chinese patientsshowed better survival compared to others in univariate and multivariate analysis. The survival of esophagealcancer patients was significantly different among ethnic groups when the data was analyzed by a univariate test(p = 0.029), but not in the Cox multivariate model adjusted for other patient and prognostic factors.Conclusions: Ethnicity may represent underlying genetic factors. Such factors could influence host-tumorinteractions by altering the tumor’s etiology and therefore its chance of spreading. Alternatively, genetic factorsmay determine response to treatments. Finally, ethnicity may represent non-genetic factors that affect survival.Differences in survival by ethnicity support the importance of ethnicity as a prognostic factor, and may provideclues for the future identification of genetic or lifestyle factors that underlie these observations

The Detection of HDL receptor on platelet surface in patients with Coronary artery disease (CAD)

The human scavenger receptor B1 (hSR-B1/CLA) is a HDL receptor with various anti-atherogenic functions which is expressed on the platelet surface. The anti thrombotic function of HDL includes the modulation of platelet reactivity, coagulation, and endothelial function. The goal of this study is to detect the level of HDL receptor on platelets of CAD patients with atherosclerotic disease. Expressions of the hSRB1 receptor on platelets of 31 CAD patients with atherosclerotic plaque and 20 healthy controls was detected using flow cytometry. Moreover, the lipid panel tests were assayed by Chemistry auto analyzer and compared with healthy controls. Our findings show that abundance of hSR-B1/CLA-1 was significantly reduced on the surface of platelets from CAD patients with atherosclerotic disease compared with healthy control (6/8 % vs. 13/6 %), (P &lt;0,001). The HDL receptor (hSR-B1/CLA-1) expression on platelets inversely correlates with the risk of coronary heart disease.  Our findings suggest that determining the level of hSR-B1/CLA-1 on the platelets may be a useful laboratory marker for CAD investigation

Design of Lentiviral Vector of Apoptin and Investigating its Cytotoxic Effect on Reh Acute Lymphoblastic Leukemia Cells

BACKGROUND AND OBJECTIVE: Resistance to chemotherapy drugs is one of the most important treatment problems in patients with acute lymphoblastic leukemia. Apoptin due to its ability to induce apoptosis in tumor cells, has an undeniable potential in cancer treatment, especially those that respond lessly to chemotherapy. Therefore, in this study, the effect of induction of apoptin expression on induction of cell death in reh malignant lymphoblasts was investigated. METHODS: In this experimental study, after culturing of Reh cells (prepared by the Pasteur Institute), the entry of lentiviral vector, metabolic activity and cell proliferation were measured using flow cytometry, MTT and trypan blue at 24, 48, 72 and 96 hours. Real time PCR was also used to determine the apoptin gene expression. FINDINGS: The results of this study indicate the design and construction of a suitable lentiviral vector that can infect more than 65% of the cells. Also, after infecting the cells with the vector, the apoptin gene expression rate was increased about 10 times to control, and subsequently, the cell viability decreased by 53% time-dependently (p <0.01) . The results also showed that the inhibitory effect of apoptin gene expression on the metabolic activity of Reh cells was about 35% (p<0.01). CONCLUSION: The results of the study showed that apoptin gene expression has anti-tumor activity in Reh cells and can be used as a promising therapy in ALL

Involvement Value of FLT-3, c-Myc, STAT3, p27, and HOTAIR Gene Expression in Acute Myeloid Leukemia Patients: A Molecular Perspective to a Novel Leukemogenesis Mechanism

Background: The identification of long non-coding RNAs (lncRNAs) in the pathogenesis of acute myeloid leukemia (AML) has marked a new era in the molecular understating of the disease. This study investigated the correlation between the changes in the expression of lncRNAs, including HOTAIR, PVT-1, and CRNDE, and the alteration in the expression profile of FLT-3, c-Myc, STAT3, STAT5, and p27 in AML patients. Materials and Methods: Blood samples were collected from forty-one newly diagnosed AML patients and ten healthy individuals to evaluate the expression levels of the study genes using qRT-PCR analysis. The probable correlation between the gene expressions was determined using Pearson’s correlation test. Results: The results showed that while there was a significant elevation in the expression of FLT3, c-Myc, STAT3, and HOTAIR, p27 expression remarkably diminished in AML patients compared to the control group. Also, a correlation was found between the expression of FLT-3 and p27 and the expression of HOTAIR and STAT3. It was assumed that FLT-3 had a role in increasing the proliferative and survival capacity of AML cells, at least partly, through c-Myc-mediated suppression of p27. Moreover, lncRNA HOTAIR showed to be involved in leukemia proliferation assumably by enhancing the expression of STAT3. Conclusion: Overall, the results of gene profile analysis suggested that studying the expression of HOTAIR, FLT-3, c-Myc, STAT3, and p27 could be helpful to AML patients, and each of these genes could be a valuable target for pharmaceutic intervention