Journal articles on the topic 'Electric field pulse motor response test'

Abstract Environmental exposure to tricresyl phosphate (TCP) may lead to severe neurotoxic effects, including organophosphate (OP)-induced delayed neuropathy. TCP has three symmetric isomers, distinguished by the methyl group position on the aromatic ring system. One of these isomers, tri-ortho-cresyl phosphate (ToCP), has been reported for years as a neuropathic OP, targeting neuropathic target esterase (NTE/PNPLA6), but its mode of toxic action had not been fully elucidated. Zebrafish eleuthero-embryo and larva were used to characterize the differential action of the TCP isomers. The symmetric isomers inhibited phenyl valerate (PV)-NTE enzymatic activity in vivo with different IC50, while no effect was observed on acetylcholinesterase activity. Moreover, the locomotor behavior was also affected by tri-para-cresyl phosphate and tri-meta-cresyl phosphate, only ToCP exposure led to locomotor hyperactivity lasting several hours, associated with defects in the postural control system and an impaired phototactic response, as revealed by the visual motor response test. The electric field pulse motor response test demonstrated that a seizure-like, multiple C-bend-spaghetti phenotype may be significantly induced by ToCP only, independently of any inhibition of PV-NTE activity. Eleuthero-embryos exposed to picrotoxin, a known gamma-aminobutyric acid type-A receptor inhibitor, exhibited similar adverse outcomes to ToCP exposure. Thus, our results demonstrated that the TCP mode of toxic action was isomer specific and not initially related to modulation of PV-NTE activity. Furthermore, it was suggested that the molecular events involved were linked to an impairment of the balance between excitation and inhibition in neuronal circuits.

This paper focuses on the steering motion control of an in-wheel motor-drive robot. The influence of the pulse-width modulation (PWM) duty cycle on steering motion and the steering control method have not yet been proved. Thus, this study aimed to design a steering controller for the off-center steer-by-wire system of a robot. The influence of the PWM duty cycle on the steering motion under different conditions is firstly tested on a test bench. Based on the optimal duty cycles of different cases found in the test, a two-stage fuzzy controller of the duty cycle is designed for the steering system. The first stage of the controller is used to dynamically adjust the PWM duty cycle of the electromagnetic friction lock (EFL). The second stage is designed to realize the self-tuning of the fuzzy controller’s quantization factor and the scale factor. Through two-stage control, the motion of the in-wheel motor and the EFL can be coordinated to realize stable and rapid steering. Considering the robots’ primary application in field roads at present, road tests were ultimately conducted to verify the proposed method. The test results show that the angle response rate of the steering arm is elevated with the increase in the steering angle signal. The proposed controller can sensitively track the target angles with smaller overshoot, yaw rate and lateral acceleration, and better steering accuracy than the PID (proportional–integral–differential) controller under different working conditions.

<span lang="EN-US">The paper describes field oriented control strategy with space vector pulse width modulation technique of permanent magnet synchronous motor drive system for an electric vehicle. At first, mathematical models of the motor and the drive system for electric vehicle are presented. In order to obtain high performance drive and maximum motor torque, field oriented control strategy and space vector pulse width modulation technique method are applied to drive system in next section. Speed controller design utilizing the popular zero-pole elimination approach causes large integral constant time in case of small rotational damping constant. The desired-transient-response-based approach is employed to overcome the problem. Performance indices include overshoot, undershoot, steady-state speed error, and total harmonic distortion of stator current, are employed to assess the drive systems with two speed controller design methods. Theoretical assumptions are confirmed via simulations and criteria in MATLAB/Simulink environment.</span>

Electric vehicles are regarded as a significant way to mitigate the global energy crisis and the environmental pollution problem. Motor control is a very important part for electric vehicles. As for hardware, a motor controller usually has components such as a power module, microprocessor unit, IGBT driver, sensors, and resolver-to-digital convertor. As for software, a field-oriented control (FOC) with space vector pulse width modulation (SVPWM) is a popular method, while model predictive control (MPC) has recently shown great potential in motor drives. In this paper, both FOC and MPC are discussed and the performances are compared based on experiments. As the implementation is on a digital processor, the discretization and normalization are addressed, and the flux observer and speed estimation are discussed. Some practical issues for implementation are also talked about, such as field weakening control, overmodulation, etc. This paper focuses on how to implement the improved motor control for electric vehicles as industrial applications. The steady-state torque performances of this motor controller are verified by motor test-bench experiments. MPC shows as good performance as FOC in these experiments.

<span lang="EN-US">Many researches have been dedicated to develop the induction motor drive control strategy used on the railway traction applications. In this paper we propose to investigate and to improve the electric locomotives by using a Field Oriented Control (FOC) strategy of induction motor drive. This induction motor can be powered by a five-stage neutral point inverter controlled by sinusoidal pulse width modulation (SPWM) due to good quality for output voltage and The use of fast switches. Both conventional and improved locomotives are simulated in Matlab/Simulink and compared in open loop conditions and closed loop conditions using IP controller, in term of torque response, current harmonic distortions and rotor speed response.</span>

In the modern oil industry, the vast majority of oil production units are represented by sucker rod pumping units, driven mainly by asynchronous electric motors without using any monitoring, control and regulation means. Studies carried out on such installations show their low energy efficiency and reliability. Therefore, the issue of developing complex electric drives of a new generation based on the use of synchronous valve electric motors is relevant allowing to significantly increase the energy efficiency and reliability of both individual installations and to ensure the creation of "smart" oil field control systems. The paper discusses new technical solutions of the experimental stand which makes it possible to study the energy characteristics of electric drives based on asynchronous and synchronous valve electric motors, as well as allowing to create conditions as close as possible to real field conditions with imitation of the operation of an oil pumping unit of a sucker rod pumping unit. In modern test equipment systems, devices are often used to create a mechanical load on the shaft of the electric motor under study. The system proposed and implemented as such a device is "a frequency converter - load asynchronous electric motor", which has been tested on a stand and has proven to be the best in comparison with traditional circuits using DC motors. But using of a load asynchronous electric motor as part of the test stand has revealed a number of disadvantages: overheating of the electric motor operating in the opposing mode, low accuracy of creating the load torque and the speed of the system's response. The problem of overheating of the load electric motor has been solved by transferring the frequency converter to the direct torque control mode, while a significant decrease in the motor current and stabilization of the temperature regime have been detected. The low accuracy and response speed of the system have been increased by introducing feedback and a PID controller into the stand control system.

High-power microwave (HPM) antenna, one of the key subsystems in the HPM system, is used for HPM radiation. Its performance is partly determined by the impulse responses of reflector materials under HPM. Therefore, it is essential to investigate the impulse response characteristics of reflector materials under HPM. Instead of the traditional waveguide cavity, this study was based on the double elliptical reflector system with an open boundary. By using this system, the impulse response of reflector materials was measured, and the response of reflector materials of multiple types under various environments with different electric field strengths and pulse widths was tested. In terms of breakdown, reflection efficiency, and pulse waveform, aluminum and carbon fiber test plates were affected by HPM and compared. Finally, the impulse response characteristics of carbon fiber test plates were summarized. The proposed method applied in this research is universal, matches the practical application environment, and can be extensively employed in the impulse response research and test of reflector materials.

This article focuses on modelling and validating a groundbreaking magnetorheological braking system. Addressing shortcomings in traditional automotive friction brake systems, including response delays, wear, and added mass from auxiliary components, the study employs a novel brake design combining mechanical and electrical elements for enhanced efficiency. Utilizing magnetorheological (MR) technology within a motor–brake system, the investigation explores the influence of external magnetic flux from the nearby motor on MR fluid movement, particularly under high-flux conditions. The evaluation of a high-magnetic-field mitigator is guided by simulated findings with the objective of resolving potential issues. An alternative method of resolving an interaction between an electric motor and a magnetorheological brake is presented. In addition, to test four configurations, multiple absorber materials are reviewed.

<p class="Abstract"><em><span lang="EN-US">T</span></em><span lang="EN-US">his paper proposes a new approach to ensure the torque decoupled to the rotor flux of an induction machine based on the Field Oriented Control (FOC). The suggested method consists of inserting into the conventional d-q synchronous current controller, coupling terms of motor and multi-level inverter models. Making, the dynamic response of stator current components decoupled as well as the rotor flux and torque. In this paper, the mathematic model of an induction motor and multi-level inverter are first derived. Then, the synchronous current controller and modulation strategy for high power inverters are investigated. Finally, the validation through implementation and simulation of a 4.16 kV electric drive with MATLAB/Simulink and SimPowerSystems is performed. The model simulated in this paper includes an induction motor, nine-level cascaded H-bridge inverter and a carrier based space vector pulse-width-modulation.</span><span lang="EN-US">The results of the simulations of each method has been recorded and the comparison results reveal that the proposed method effectively maintains the rotor flux decoupled to the torque.</span></p>

This paper introduces a new technique to test fatigue cracks in concrete that occur during its maintenance. The principle of the technique consists of exposing the object to pulsed mechanical excitation. As a result, acoustic waves start to propagate in the sample. Under the action of acoustic waves the dipole moments of double electric layers on the boundaries of components in concrete are changed and piezoquartz which is a part of sand and gravel is polarized. The external electric field occurs and is registered by a signal receiver placed near the object under study. The possibility of using this technique for crack nondestructive control is studied in the paper. The technique capabilities are shown by comparing the parameters of electric response on pulsed mechanical excitation when testing the defectless concrete and the same sample after developing the artificial crack in the concrete.

Permanent magnet synchronous motor (PMSM) speed control is generally done using flux-oriented control, which uses conventional proportional-integral (PI) current regulators, but still remain the problem of calculating the coefficients of these regulators, particularly in the case of control hybridization, the development of artificial intelligence has simplified many calculations while giving more accurate, and improved results, this paper presents and compares the performance of the flux oriented control (FOC) of a PMSM powered by pulse width modulation (PWM) using PI regulator, fuzzy logic control (FLC) and adaptive neuro-fuzzy inference system (ANFIS), in this work we present another approach of a neuro ANFIS using the hybrid combination of fuzzy logic and neural networks. This ANFIS is a very powerful tool and can be applied to various engineering problems. To make up for the deficiency of fuzzy logic controller. To understand the performance, characteristics, and influence of each controller on the system response, we use MATLAB/Simulink to model a PMSM (0.5 kW) powered by a three-phase inverter and controlled by the FOC, FOC-FLC, and FOC-ANFIS.

Electrical capacitance tomography (ECT) is a technique of imaging the distribution of permittivity inside an object under test. Capacitance is measured between the electrodes surrounding the object, and the image is reconstructed from these data by solving the inverse problem. Although both sinusoidal excitation and pulse excitation are used in the sensing circuit, only the AC method is used to measure both components of complex capacitance. In this article, a novel method of complex capacitance measurement using pulse excitation is proposed for ECT. The real and imaginary components are calculated from digital samples of the integrator response. A pulse shape in the front-end circuit was analyzed using the Laplace transform. The numerical simulations of the electric field inside the imaging volume as well as simulations of a pulse excitation in the front-end circuit were performed. The calculation of real and imaginary components using digital samples of the output signal was verified. The permittivity and conductivity images reconstructed for the test object were presented. The method enables imaging of permittivity and conductivity spatial distributions using capacitively coupled electrodes and may be an alternative measurement method for ECT as well as for electrical impedance tomography.

This paper presents a Markov chain random carrier frequency modulation (MRCFM) technique for suppressing sideband vibro-acoustic responses caused by discontinuous pulse-width modulation (DPWM) in permanent magnet synchronous motors (PMSMs) for new energy vehicles. Firstly, the spectral and order distributions of the sideband current harmonics and radial electromagnetic forces introduced by DPWM are characterized and identified. Then, the principle and implementation method of three-state Markov chain random number generation are proposed, and particle swarm optimization (PSO) algorithm is chosen to quickly find the key parameters of transition probability and random gain. A Simulink and JMAG multi-physics field co-simulation model is built to simulate and predict the suppression effect of the MRCFM method on the sideband vibro-acoustic response. Finally, a 12-slot-10-pole PMSM test platform is built for experimental testing. The results show that the sideband current harmonics and vibro-acoustic response are effectively suppressed after the optimization of Markov chain algorithm. The constructed multi-physics field co-simulation model can accurately predict the amplitude characteristics of the sideband current harmonics and vibro-acoustic response.

The 6-DOF vibration isolation platform (VIP) is used to isolate vibration in the processing and manufacturing of semiconductor chips, especially electric vehicle chips. The 6-DOF VIP has the characteristics of high position accuracy, fast dynamic response, and short motion travel. In this paper, a novel four-quadrant Lorentz force motor (FQLFM) applied on the 6-DOF VIP is proposed. The structure of this LFM has a high force density, low force fluctuation, and low coupling force. First, the basic structure and operating principle of the proposed FQLFM are presented. Secondly, the expressions of the magnetic field and electromagnetic force are obtained based on an equivalent current model and the permanent magnet mirror-image method (PMMIM). Thirdly, the magnetic field and electromagnetic force characteristics of the proposed FQLFM and an LFM with a traditional bilateral structure are analyzed and compared. The relationship between the force and displacement of the FQLFM is investigated. Moreover, the PMMIM is verified by a 3D finite element analysis (FEA). Finally, the experimental platform for a force test is built and the above results are validated by an experiment.

Highlights. Seed meter rpm error decreased with increasing planter speed during steady states.Point-row operations could result in up to 10-13 seeds being over- or under-planted.Seed meter rpm error varied from -7.2% to 7.9% during curve planting transient states. Abstract. Electric drive seed metering systems have become a common method for singulating row crop seed. These singulation systems have substantially fewer moving parts and can potentially respond more quickly than other drive mechanisms. However, the accuracy and response time of these systems has yet to be examined to quantify potential benefits of adoption. The objectives of this study were (1) to quantify accuracy and response time of electric meter drives to varying ground speeds and speed transitions during in-lab simulation planting operations on straight-line and curves, and (2) to compare actual seed meter motor speed to target meter speed during simulation field scenarios. To quantify metering system performance, test scenarios were developed to simulate planting on headlands, within field boundaries including traversing in-field obstacles, and planting on curves with different radii. Ground speeds during simulation scenarios were 7.2, 12.9, and 16.1 kph when operating on straight rows and 6.0, 8, 11, and 14.5 kph when planting along curvilinear paths. Test scenarios also included planter acceleration and deceleration at 0.4 and 0.6 m/s2 when traversing in-field obstacles and tighter radii curves. Tests were conducted with two different seeding rates, 44,460 and 88,920 seeds/ha. Eight high frequency encoders were mounted on the electric meters of selected row units to record real-time meter rpm and quantify seed meter accuracy and response time. A custom DAQ system was developed to read simulation test scenario data files in ASCII text file format and send prescribed ground speed commands to the Horsch Maestro 24.30 planter’s ECU at 10 Hz using a program written in LabVIEW. Results indicated that seed metering accuracy increased as ground speed increased resulting in a significantly lower seed meter rpm error at 16.1 kph under steady-state conditions. During transient states, seed meters needed 3 to 4 s to respond during deceleration and acceleration resulting to seed meter rpm error ranging from -3.7% to 3.6% at 44,460 seeds/ha seeding rate and from -3.8% to 3.2% at 88,920 seeds/ha seeding rate. During point-row operations, the response time of the meters was 0.4 s which could result in up to 10 seeds being under-planted and up to 13 seeds being over-planted per row unit. During curvilinear planting, seed meter rpm error for steady states ranged from -0.5% to 0.8% across varying turn radii resulting to seeding rate error ranging from -223 to 370 seeds/ha while during transient states seed meter rpm error varied from -7.2% to 7.9% resulting to seeding rate error ranging from -5,886 to 7,187 seeds/ha. Keywords: Seed meter rpm, Seeding rate error, Simulation, Variable rate planting, Planter meter.

In order to solve the problems of traditional seeders, such as low seeding efficiency, tangled straw, a large amount of clay, easy ridge breakage in sowing operations, low qualified rate of high-speed seeding, and poor uniformity, this paper takes the pneumatic corn planter as the research object, the Beidou automatic driving unit as the carrier, the CAN (Controller Area Network) bus as the communication medium, and the double closed-loop fuzzy PID (proportion-integral-derivative) algorithm as the control core and designs a high-speed precision corn seeding control system based on Beidou navigation. It solves the problems that exist in traditional planters. In the bench experiment, the stability of the system is judged by comparing the motor control accuracy with ordinary PID and measuring the motor response time of the system at different speeds. The bench test results show that when the theoretical seeding speed is 0~34 r·min−1, the response time of the motor is shortened by 0.51 s compared with the ordinary PID control, and the error between the actual speed and the target value is less than 0.35%. The field experiment results show that when the unit runs for 5~13 km·h−1, the qualified rate of average planting spacing is greater than 95.81%, the reseeding rate is less than 10.11%, and the coefficient of variation is less than 16.72%, which complies with the standard of a corn sowing operation.

Electric vehicles (EVs) have the main advantage of using sustainable forms of energy to operate and can be integrated into electrical power grids for better energy management. An essential part of the EV propulsion system is the type of motor used to propel the EV. Permanent magnet synchronous motors (PMSMs) have found extensive use due to various advantages such as high power density, excellent torque-to-weight ratio and smooth speed profile over the entire torque range. The objective of this paper was to improve the dynamic response in the speed profile for different driving conditions essential in EVs. This was done by using the finite control set model predictive control (FCS-MPC) algorithm for PMSM and by comparing and evaluating the control strategies of a PMSM used in an EV by taking two case studies. The classical control, namely field-oriented control (FOC), of PMSMs is slow to adopt the dynamic changes in the system. The proposed FCS-MPC algorithm for PMSMs provides an improved dynamic response and a good steady-state response for the different driving conditions shown in both cases. In addition, the Worldwide Harmonized Light Vehicles Test Procedure (WLTP) is used to evaluate the FCS-MPC-controlled PMSM to depict its superior performance by matching its speed profile. The results are verified in the hardware in the loop strategy using OPAL-RT. Both the results confirm that the FCS-MPC algorithm, when compared with the conventional FOC, is superior in aspects of steady-state and dynamic responses for various torque and speed profiles.

Introduction. In recent decades, there have been created powerful pulsed sources of electromagnetic radiation capable of generating and transmitting high peak signals with effective antennas. Wide-band and ultra-wide-band (NB, UWB) generator complexes in the frequency range from 0.5 Hz to 100 Hz, concentrating the energy in ultrashort pulses in duration, have become widespread. Most studies of the biological effects of these radiations are associated with their special purpose (directional action). Today, high-voltage pulsed radiation is widely used in such areas as radiolocation and navigation, radio communication, in semiconductor and composite technology, chemical compounds, medicine, and others. Biomedical aspects of ultra-wideband radiation pulses have not been studied enough. The issues of the safety and regulation for occupational exposure are considered. The studies of broadband electromagnetic pulses effect on outbred white mice during generator equipment testing were carried out in experimental conditions. Material and methods. Behavioral responses in the “open field” test, memory in a “T-shaped maze”, working capacity in “forced swimming” test were studied, as well the temperature response, electrostatic body potential and body mass were measured. The studies were implemented in an anechoic chamber. The antenna system of the high-voltage pulse generator enabled us to generate a uniform field having a volume sufficient for the group exposure. Pulse simulator was remote-controlled. The study covered three groups of animals exposed daily for 15, 30 and 60 minutes during five days and a control group. Animals were studied during and after expose periods. Results. Statistically significant changes were revealed in 30 and 60 minutes daily exposure to 100 kV / m voltage pulses, which evidences disturbances in behavioral responses, motor activity, memory, and work capacity. A decline in the electrostatic body potential was shown. Thermogenic effect was not seen. The pilot study findings prove the biological activity of broadband electromagnetic pulses in short-term experiment.

This paper used the 4UM-120D electric leafy vegetable harvester as the research object and designed a travel speed automatic control system to maintain the travel speed within a set value of ±2% in order to improve the efficiency and quality of leafy vegetable harvester operations and decrease the work intensity of the operator. The harvester’s travel speed was automatically controlled by using the PID, adaptive fuzzy PID, and sliding mode control techniques after the mechanical and electrical equations for the travel drive motor (a DC brushless motor) were established in MATLAB. By simulating various working situations, the stability, accuracy, and speed of the automatic control system were compared and analyzed using the adjustment time, overshoot, steady-state transition time, and maximum deviation from the set speed as evaluation indicators. The test results revealed that when the current value of the leafy vegetable harvester travel speed deviated from the set value by more than 2%, the dynamic response performance and stability of the DC brushless motor travel drive system based on the sliding mode control strategy was significantly better than that of the PID and adaptive fuzzy PID control strategies, and its anti-disturbance was stronger, achieving the function of automatic control of the harvester travel speed. When the travel motor started with a constant load and the sliding mode control strategy’s parameters were the gain factors A = 1/70, c = 100, ε = 100, and k = 100, the travel drive system regulation time was 1.5 s, and the overshoot was 10%. When the harvester was operating smoothly and had leafy vegetable collection baskets loaded and unloaded, the steady-state transition time was 0.3 s. According to the actual engineering application experience, the specific technical state of the control strategy of the agricultural machinery travel speed automatic control system was: regulation time 2.5~3 s; overshoot amount 20~25%; and steady-state transition time 1.0~1.5 s, so the travel speed automatic control system of the electric leafy vegetable harvester in sliding mode was in line with the technical state requirements. The results of the field trials demonstrated the accuracy of the simulation test results. This study offered a method to lessen the work intensity of operators and increase the operating efficiency and quality of a leafy vegetable harvester.

Fast-switching valves driven by puse width modulation have been widely used in the hydraulic braking systems (such as anti-lock braking systems or electric stability control systems) of vehicles, because of their lower cost and their functions which are similar to those of proportional valves. However, proportional valves have been widely investigated, whereas there is significantly less literature on the switching valves of the hydraulic control units in the braking systems of vehicles. In order to investigate the controllability of pressure, construction of an accurate theoretical model is the key to attaining this. Based on theoretical analysis and finite element analysis, this paper presents a non-linear dynamics model of a typical fast-switching valve. The non-linear model is composed of three submodels: a mechanical submodel, an electromagnetic submodel and a fluid dynamics submodel. The fluid momentum theorem combined with the simulation curve-fitting method is used to model accurately the fluid dynamics which are due to the varying flow field. The hydraulic force acting on the spool can be obtained directly from this model. Finally, the feasibility of the response time and the pressurization performance of the non-linear dynamics model is proved by comparing the simulation results from MATLAB/Simulink with the experimental results obtained on a test bench. The study shows that the model can be regarded as a predictive tool for future investigation.

Besides stimulus intensities and interstimulus intervals (ISI), the electric field (E-field) orientation is known to affect both short-interval intracortical inhibition (SICI) and facilitation (SICF) in paired-pulse transcranial magnetic stimulation (TMS). However, it has yet to be established how distinct orientations of the conditioning (CS) and test stimuli (TS) affect the SICI and SICF generation. With the use of a multi-channel TMS transducer that provides electronic control of the stimulus orientation and intensity, we aimed to investigate how changes in the CS and TS orientation affect the strength of SICI and SICF. We hypothesized that the CS orientation would play a major role for SICF than for SICI, whereas the CS intensity would be more critical for SICI than for SICF. In eight healthy subjects, we tested two ISIs (1.5 and 2.7 ms), two CS and TS orientations (anteromedial (AM) and posteromedial (PM)), and four CS intensities (50, 70, 90, and 110% of the resting motor threshold (RMT)). The TS intensity was fixed at 110% RMT. The intensities were adjusted to the corresponding RMT in the AM and PM orientations. SICI and SICF were observed in all tested CS and TS orientations. SICI depended on the CS intensity in a U-shaped manner in any combination of the CS and TS orientations. With 70% and 90% RMT CS intensities, stronger PM-oriented CS induced stronger inhibition than weaker AM-oriented CS. Similar SICF was observed for any CS orientation. Neither SICI nor SICF depended on the TS orientation. We demonstrated that SICI and SICF could be elicited by the CS perpendicular to the TS, which indicates that these stimuli affected either overlapping or strongly connected neuronal populations. We concluded that SICI is primarily sensitive to the CS intensity and that CS intensity adjustment resulted in similar SICF for different CS orientations.

Due to the harsh working environment of wheeled agricultural vehicles in the field, it is difficult to ensure that all wheels make contact with the ground at the same time, which is easy to unequally distribute the yaw moments of each independent wheel. The commonly used vehicle lateral control methods are mostly controlled by coordinating the individual torque between different wheels. Obviously, this control method is not suitable for agricultural four-wheeled vehicles. The goal of this study was to provide a wheel steering angle control method that uses electric push rods as actuators that can cope with this problem. The design of a four-wheel steering controller generally adopts the linear PID control method, but the research object of this paper is difficult to establish an accurate and linear mathematical model due to the complex working environment. Therefore, fuzzy adjustment is added on the basis of PID control, which can meet the requirements of model difficulty and control accuracy at the same time. In order to verify the feasibility and rationality of the designed wheel steering mechanism, the model dynamics simulation based on ADAMS software and the response analysis of the electric linear actuator thrust were completed. Based on the kinematics model of the controlled object, the rotation angle of the actuator motor is used as the control target, the lateral deviation e and deviation variation ec are taken as input variables and the parameters KP, KI and KD are taken as output variables, thereby establishing a fuzzy PID controller. Then, this controller is constructed in the Matlab/ Simulink simulation environment to analyze the lateral deviation and response stability during the process of vehicle path tracking. From the verification results of the linear path walking test under the fuzzy PID control method, the maximum lateral deviation of vehicle chassis is 2.7 cm when the driving speed is set as 1 m/s, and the deviation adjustment stable time of the system is 0.15 s. It can be seen that the proposed steering control strategy has good response performance and effectively increases the steering stability.

Background: Regional anaesthesia like brachial plexus blocks are increasingly practiced now a day’s for forearm surgery. A major limitation of brachial plexus block which may lead to unplanned general anesthesia is inconsistent block. Conventional nerve localization techniques which rely on surface anatomical landmarks may not provide satisfactory anesthesia. Aims and Objectives: In recent years, real time ultrasound guidance has been introduced as an aid to nerve localization. This study was planned to test the hypothesis that the quality of the axillary brachial plexus blockade guided by ultrasound was better than those using surface anatomical landmarks and produced fewer adverse effects and overall success in cases of forearm surgeries.Materials and Methods: After obtaining institutional ethics committee approval and written informed consent, 100 patients of American Society of Anesthesiologists grade I or II scheduled for forearm surgeries were included in the study and were randomly allocated into two groups. The brachial plexus blockade via axillary approach guided by ultrasound and traditional nerve localization techniques which rely on surface anatomical landmarks, patient report of paresthesia, and/or elicitation of a motor response by mechanical nerve stimulator or electric nerve stimulation with single-injection method was carried out in the two groups of patients respectively.Results: The patients (n=100) predominantly female (55%) with comparable demographic profile found to have statistically insignificant changes in the mean pulse rate, blood pressure, respiratory rate changes and oxygen saturation of hemoglobin during the surgical operations. Overall block success rate, blockade of each individual target nerve was better and procedural hazards were less in the ultrasound guided group.Conclusion: Real time ultra sound guided axillary nerve block is better than traditional palpable method with lesser adverse outcome.Asian Journal of Medical Sciences Vol.8(2) 2017 69-75

Vertical gallium nitride (GaN) power devices continue to garner interest in multiple power conversion applications requiring a medium-voltage (1.2 – 20 kV) capability. Currently, silicon carbide (SiC) is addressing this voltage range, however, with a comparable critical electric field and superior mobility, GaN is expected to offer advantages in applications where fast switching and avalanche breakdown response times are desired. While uses in electric vehicles, solid-state transformers, and renewable energy conversion are being actively explored, the potential of a vertical GaN device for electric grid protection in the form of an electromagnetic pulse arrestor is a unique proposition that requires very fast transient capabilities (<1 µs pulse widths with rise-times on the order of 10 ns). However, vertical GaN devices are significantly less mature than present SiC offerings. Specifically, low-doped, thick epitaxial growth of GaN via metal-organic chemical vapor deposition (MOCVD) still presents many challenges, and advancements in processing, manufacturability, and failure analysis are needed. In this work, we describe our efforts to address the above issues and advance the state-of-the-art in vertical GaN PN diode development. We have successfully demonstrated an MOCVD-grown, 50 µm thick, low-doped (<1015 cm-3) drift region on a GaN substrate that was processed into relatively large-area (1 mm2) PN diodes capable of achieving a 6.7 kV breakdown. Temperature-dependent breakdown was observed, consistent with the avalanche process. The devices consisted of a 4-zone step-etched junction termination extension (JTE), where the breakdown region was visualized via electroluminescence (EL) imaging. Ongoing work aims to scale the current capability of the medium-voltage diodes through a parallel interconnect design that negates defective or poor performing diodes. Further investigation of edge termination structures was explored using a bevel approach, where we studied the relationship between the bevel angle and p-doping. It was found that a very shallow angle of only 5° accompanied by a 500 nm p-region consisting of 3×1017 cm-3 Mg concentration resulted in a consistent 1.2 kV breakdown for an 8 µm thick, 1.6×1016 cm-3 doped drift region. EL imaging confirmed uniform breakdown, and temperature dependence was demonstrated. The bevel approach was then implemented on a diode structure with a 20 µm thick drift region capable of 3.3 kV breakdown, where an unclamped inductive switching (UIS) test was performed to evaluate the impact of a field plate design on avalanche uniformity and ruggedness. A parallel effort to establish a foundry process for vertical GaN devices has been underway. Initially, this focus was on comprehensive studies of GaN wafer metrology using capacitance-voltage (C-V) mapping, optical profilometry, and x-ray diffraction (XRD) mapping. A machine learning algorithm was implemented to identify defective regions and produce a yield prediction for each GaN wafer prior to processing. A hybrid edge termination structure consisting of implanted guard rings (GR) and JTEs was developed in coordination with a controlled experiment that varied the anode thickness, and therefore the remaining p-GaN after implantation. It was observed that thinner p-GaN regions under the JTE/GR region resulted in a significant (>100x) reduction in leakage current under reverse-bias conditions. This process has resulted in 1.2-kV-class devices with up to 18 A forward current for a 1 mm2 device with a specific on-resistance of 1.2 mOhm-cm2. The foundry effort has since been extended to 3.3-kV-class devices that utilize 25 µm thick drift layers with ~2-4×1015 cm-3 doping. These devices have demonstrated up to 3.8 kV breakdown with leakage currents <1 nA up to 3 kV. More than 40 wafers have been processed to date, resulting in >20,000 devices. Statistical variations in I-V and C-V characteristics will be discussed. Packaging process development and analysis are underway to develop electrical stress procedures and identify fundamental failure mechanisms. Finally, a pulse arrested spark discharge (PASD) setup, capable of up to 15 kV pulsed operation in 100 V steps, was implemented to quantify the time response of avalanche breakdown. Initial results on a packaged 800 V device showed a ~1 ns response time during breakdown, which reinforces the potential EMP grid protection applicability. This work was supported by the ARPA-E OPEN+ Kilovolt Devices Cohort directed by Dr.Isik Kizilyalli. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy of the United States Government.

Induction Motor in Electrical drive system at a accelleration speed for example in electric cars have a hard speed setting is set on a wide range, causing an inconvenience for motorists and a fast response is required any change of speed. It is necessary for good system performance in control motor speed and torque at low speed or fast speed response, which is operated by Indirect Field Oriented Control (IFOC). Speed control on IFOC methods should be better to improving the performance of rapid response in the induction motor. In this paper presented a method of incorporation of Fuzzy Logic Controller and Backstepping (Fuzzy-Backstepping) to improve the dynamically response speed and torque in Induction Motor on electric car, so we get smoothness at any speed change and braking as well as maximum torque of induction motor. Test results showed that Fuzzy-Backstepping can increase the response to changes speed in electric car. System testing is done with variations of the reference point setting speed control system, the simulation results of the research showed that the IFOC method is not perfect in terms of induction motor speed regulation if it’s not use speed control. Fuzzy-Backstepping control is needed which can improve the response of output, so that the induction motor has a good performance, small oscillations when start working up to speed reference.Keywords: Fuzzy-Backstepping, IFOC, induction motor

Flexible micro/nano motors responsive to light sources are highly desirable. Conventional photothermal (PT) techniques have provided significant light-actuation methods; however, the dynamic responses of these devices in high frequency domain are severely restricted by the frequency response limitation. To overcome this limitation, the thermal-, electric-, and acoustic-near field interactions in the PT process and its accompanied photoacoustic (PA) process are investigated, and a plasmon enhanced PA actuation method is proposed. The significant improvement in PA oscillation by strong localized surface plasmon resonance provides a powerful means to realize a broadband response laser motor without the frequency response limitation. This PA laser motor could generate PA oscillation of over 5 µm by pulse laser with repetition frequencies of 1 Hz to 20 kHz and has a maximum value of 18.8 µm at the mechanical resonant frequency. It demonstrates the effectiveness of this PA laser motor in offsetting the shortcomings of the PT actuation method. The device requires no electrical or chemical energy, and it has potential benefits, such as bionic research into insect flapping, vocal-cord vibration, and muscular movement in fields including micro/nano physics, biochemistry, and clinical medicine.

This paper proposes the brushless direct current (BLDC) motor with high power density and high efficiency characteristics may be used to propulsion framework for electric vehicle. The progressive model for BLDC motor under rotor flux linkage route reference frame might have been providing. Here we analyzed the chart of ann vector and principal of ann control strategies and proposing the ann based reactive power with BLDC motor. To make ann based framework on active power, torque ripple, dc voltage, power factors can be used BLDC motor was designed. After designed simulation results was test the validity of field weakening based on reactive power with BLDC for electric vehicle application. In this research work will introduced artificial neural network (ANN) for non electrical input used. To control the BLDC motor speed it can using pulse width modulated control of the voltage source inverter (VLSI) using DC link voltage (Vdc) controller. To perform electronic commutation by hall signal sensing they are using PWM signal, to generate PWM signal inbuilt encoder can be used in this circuit. Analyze the BLDC motor performance driving propulsion framework is carried out under the MATLAB/Simulink software’s and efficiency of whole frame work is calculated under various source conditions

The NVH performance of electric vehicles is crucial for human comfort, and the electric drive system is key to NVH performance. Permanent magnet synchronous motors experience high-temperature increases under high-speed operating conditions, resulting in motor structure deformation at high-temperatures. The radial deformation of the stator alters the airgap dimensions of the motor’s electromagnetic field. The airgap of the motor’s magnetic field has high-sensitivity to these changes aggravating the vibration and noise problems. Harmonic currents in high-speed vehicle motors add to these problems. Therefore, motor dynamics must be studied under the joint influences of airgap distortion and harmonic currents. We proposed a method of modeling permanent magnet synchronous motors under the joint effect of harmonic currents and temperature fields. And established an accurate multi-field coupled vibration response prediction model for permanent magnet synchronous motors. The accuracy of the vibration prediction model was subjected to a bench test. The vibration characteristics of the motor were studied using order and spectrum analyses. We found that the airgap magnetic-field distortion, due to the motor and stator thermal deformation, significantly affected the motor vibration characteristics. The main motor vibration noise was caused by the 24th and 48th order electromagnetic force waves. This provides a reference for establishing an accurate vibration prediction model for permanent magnet synchronous motors.

Abstract We derived computationally efficient average response models of different types of cortical neurons, which are subject to external electric fields from Transcranial Magnetic Stimulation. We used 24 reconstructions of pyramidal cells (PC) from layer 2/3, 245 small, nested, and large basket cells from layer 4, and 30 PC from layer 5 with different morphologies for deriving average models. With these models, it is possible to efficiently estimate the stimulation thresholds depending on the underlying electric field distribution in the brain, without having to implement and compute complex neuron compartment models. The stimulation thresholds were determined by exposing the neurons to TMS-induced electric fields with different angles, intensities, pulse waveforms, and field decays along the somato-dendritic axis. The derived average response models were verified by reference simulations using a high-resolution realistic head model containing several million neurons. The relative errors of the estimated thresholds between the average model and the reference model ranged between -3% and 3.7% in 98% of the cases, while the computation time was only a fraction of a second compared to several weeks. Finally, we compared the model behavior to TMS experiments and observed high correspondence to the orientation sensitivity of motor evoked potentials. The derived models were compared to the classical cortical column cosine model and to simplified ball-and-stick neurons. It was shown that both models oversimplify the complex interplay between the electric field and the neurons and do not adequately represent the directional sensitivity of the different cell types The derived models are simple to apply and only require the TMS induced electric field in the brain as input variable. The models and code are available to the general public in open-source repositories for integration into TMS studies to estimate the expected stimulation thresholds for an improved dosing and treatment planning in the future

Abstract Objective: Transcranial magnetic stimulation (TMS) coil design involves a tradeoff among multiple parameters, including magnetic flux density (B), inductance (L), induced electric (E) field, focality, penetration depth, coil heating, etc. Magnetic materials with high permeability have been suggested to enhance coil efficiency. However, the introduction of magnetic core invariably increases coil inductance compared to its air-core counterpart, which in turn weakens the E field. Our lab previously reported a rodent-specific TMS coil with silicon steel magnetic core, achieving 2 mm focality. This study aims to better understand the tradeoffs among B, L and, E in the presence of magnetic core.&#xD;Approach: The magnetic core initially operates within the linear range, transitioning to the non-linear range when it begins to saturate at high current levels and reverts to the linear range as coil current approaches zero; both linear and non-linear analyses were performed. Linear analysis assumes a weak current condition when magnetic core is not saturated; a monophasic TMS circuit was employed for this purpose. Non-linear analysis assumes a strong current condition with varying degrees of core saturation. &#xD;Main Results: Results reveal that, the secondary E field generated by the silicon steel core substantially changed the dynamics during TMS pulse. Linear and non-linear analyses revealed that higher inductance coils produced stronger peak E fields and longer E field waveforms. On a macroscopic scale, the effects of these two factors on neuronal activation could be conceptually explained through a one-time-constant linear membrane model. Four coils with different B, L and, E characteristics were designed and constructed. Both E field mapping and experiments on awake rats confirmed that inductance could be much higher than previously anticipated, provided that magnetic material possesses a high saturation threshold.&#xD;Significance: Our results highlight the novel potentials of magnetic core in TMS coil designs, especially for small animals. &#xD;

The open field test (OFT) is a basic and most widely used test for investigation in animal studies of the neurobiological basis of anxiety and screening for novel drug targets. Here, we present the results of an OFT for weakly electric fish Gnathonemus petersii. This study aimed to describe the behavioral response of G. petersii exposed to an OFT, simultaneously with an evaluation of electrical organ discharges (EOD), to determine whether any association between EOD and patterns of motor behavior in the OFT exists. Treatment of OFT activity and its temporal patterning was assessed for the whole 6-min trial as well as per-minute distributions of activity using a near-infrared camera and an EOD data acquisition system. Our results demonstrated that the time spent, distance moved, and time of activity were significantly higher in the periphery of the OFT arena. The zone preference pattern over the 6-min test session showed that G. petersii prefer the outer zone (83.61%) over the center of the arena (16.39%). The motor behavior of fish measured as distance moved, active time, and swim speed were correlated with the number of EODs; however, no relationship was found between EOD and acceleration.

AbstractTranscranial magnetic stimulation (TMS)–evoked electroencephalography (EEG) potentials (TEPs) provide unique insights into cortical excitability and connectivity. However, confounding EEG signals from auditory and somatosensory co-stimulation complicate TEP interpretation. Our optimized sham procedure established with TMS of primary motor cortex (Gordon in JAMA 245:118708, 2021) differentiates direct cortical EEG responses to TMS from those caused by peripheral sensory inputs. Using this approach, this study aimed to investigate TEPs and their test–retest reliability when targeting regions outside the primary motor cortex, specifically the left angular gyrus, supplementary motor area, and medial prefrontal cortex. We conducted three identical TMS–EEG sessions one week apart involving 24 healthy participants. In each session, we targeted the three areas separately using a figure-of-eight TMS coil for active TMS, while a second coil away from the head produced auditory input for sham TMS. Masking noise and electric scalp stimulation were applied in both conditions to achieve matched EEG responses to peripheral sensory inputs. High test–retest reliability was observed in both conditions. However, reliability declined for the ‘cleaned’ TEPs, resulting from the subtraction of evoked EEG response to the sham TMS from those to the active, particularly for latencies > 100 ms following the TMS pulse. Significant EEG differences were found between active and sham TMS at latencies < 90 ms for all targeted areas, exhibiting distinct spatiotemporal characteristics specific to each target. In conclusion, our optimized sham procedure effectively reveals EEG responses to direct cortical activation by TMS in brain areas outside primary motor cortex. Moreover, we demonstrate the impact of peripheral sensory inputs on test–retest reliability of TMS-EEG responses.

BACKGROUND: To determine if low-frequency repetitive transcranial magnetic stimulation targeting the primary motor cortex contralateral (M1 CL ) to the affected corticospinal tract in patients with hemiparetic stroke augments intensive training–related clinical improvement; an extension of the NICHE trial (Navigated Inhibitory rTMS to Contralesional Hemisphere Trial) using an alternative sham coil. METHODS: The present E-FIT trial (Electric Field Navigated 1Hz rTMS for Post-stroke Motor Recovery Trial) included 5 of 12 NICHE trial outpatient US rehabilitation centers. The stimulation protocol remained identical (1 Hz repetitive transcranial magnetic stimulation, M1 CL , preceding 60-minute therapy, 18 sessions/6 wks; parallel arm randomized clinical trial). The sham coil appearance mimicked the active coil but without the weak electric field in the NICHE trial sham coil. Outcomes measured 1 week, and 1, 3, and 6 months after the end of treatment included the following: upper extremity Fugl-Meyer (primary, 6 months after end of treatment), Action Research Arm Test, National Institutes of Health Stroke Scale, quality of life (EQ-5D), and safety. RESULTS: Of 60 participants randomized, 58 completed treatment and were included for analysis. Bayesian analysis of combined data from the E-FIT and the NICHE trials indicated that active treatment was not superior to sham at the primary end point (posterior mean odds ratio of 1.94 [96% credible interval of 0.61–4.80]). For the E-FIT intent-to-treat population, upper extremity Fugl-Meyer improvement ≥5 pts occurred in 60% (18/30) active group and 50% (14/28) sham group. Participants enrolled 3 to 6 months following stroke had a 67% (31%–91% CI) response rate in the active group at the 6-month end point versus 50% in the sham group (21.5%–78.5% CI). There were significant improvements from baseline to 6 months for both active and sham groups in upper extremity Fugl-Meyer, Action Research Arm Test, and EQ-5D ( P <0.05). Improvement in National Institutes of Health Stroke Scale was observed only in the active group ( P =0.004). Ten serious unrelated adverse events occurred (4 active group, 6 sham group, P =0.72). CONCLUSIONS: Intensive motor rehabilitation 3 to 12 months after stroke improved clinical impairment, function, and quality of life; however, 1 Hz-repetitive transcranial magnetic stimulation was not an effective treatment adjuvant in the present sample population with mixed lesion location and extent. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03010462.

Electric vehicle (EV) are being embraced in recent times as they run on clean fuel, zero tail emission and are environment-friendly. Recent advancements in the field of power electronics and control strategies have made it possible to the advent in the vehicle dynamics, efficiency and range. This paper presents a design for traction control system (TCS) for longitudinal stability and Direct Yaw Control (DYC) for lateral stability simultaneous. The TCS and DYC is based on multiple frequency controlled electronic differential with a simple and effective approach. Along with it, some overviews have been presented on some state of the art in traction control system (TCS) and torque vectoring. The developed technique reduces nonlinearity, multisensory interfacing complexity and response time of the system. This torque and yaw correction strategy can be implemented alongside fuzzy control, sliding mode or neural network based controller. The effectiveness of the control method has been validated using a lightweight neighbourhood electric vehicle as a test platform. The acquired results confirm the versatility of proposed design and can be implemented in any DC motor based TCS/DYC.

Abstract Purpose In recent years, irreversible electroporation (IRE) has been developed to specifically destroy undesirable tissues as an alternative to surgical resection. In this treatment, placing multiple electrodes in parallel is required to create a uniform electric field distribution. The process of maintaining parallel electrodes is challenging, and the effect of the electrodes’ orientation accuracy has not been investigated quantitatively. This study investigates the impact of the electrode orientation along with various electrode and pulse parameters on the outcomes of IRE. Methods The electrode configurations that were considered were parallel, forward, and sideward orientation. A numerical model was developed to study the effect of electrode orientation on the electric field distribution, which was validated experimentally on potato tubers as it has similar properties to biological tissue. In addition, a conductivity test was performed to evaluate the conductivity and electroporation threshold of the potatoes. Results The developed numerical model was validated by comparing the electroporated volumes between potatoes from the experiment and simulation, which achieved a mean dice score of $$0.727\pm 0.046$$ 0.727 ± 0.046 . The potato has an electrical conductivity of 0.044–0.454 S/m with an electroporation threshold of 375 V/cm. ANOVA test showed that the difference in the electroporated regions obtained between a parallel orientation and a 5$$^{\circ }$$ ∘ forward and sideward orientation was not significant. Conclusion This study showed that the developed numerical models were validated and able to predict the outcome of IRE on potatoes. In addition, a 5$$^{\circ }$$ ∘ tolerance on the electrode orientation can be defined to obtain a similar response to the parallel orientation.

AbstractIn parkinsonism, subthalamic nucleus (STN) electrical deep brain stimulation (DBS) improves symptoms, but may be associated with side effects. Adaptive DBS (aDBS), which enables modulation of stimulation, may limit side effects, but limited information is available about clinical effectiveness and efficaciousness. We developed a brain-machine interface for aDBS, which enables modulation of stimulation parameters of STN-DBS in response to γ2 band activity (80-200 Hz) of local field potentials (LFPs) recorded from the primary motor cortex (M1), and tested its effectiveness in parkinsonian monkeys. We trained two monkeys to perform an upper limb reaching task and rendered them parkinsonian with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Bipolar intracortical recording electrodes were implanted in the M1, and a recording chamber was attached to access the STN. In aDBS, the M1 LFPs were recorded, filtered into the γ2 band, and discretized into logic pulses by a window discriminator, and the pulses were used to modulate the interval and amplitude of DBS pulses. In constant DBS (cDBS), constant stimulus intervals and amplitudes were used. Reaction and movement times during the task were measured and compared between aDBS and cDBS. The M1-γ2 activities were increased before and during movements in parkinsonian monkeys and these activities modulated the aDBS pulse interval, amplitude, and dispersion. With aDBS and cDBS, reaction and movement times were significantly decreased in comparison to DBS-OFF. The electric charge delivered was lower with aDBS than cDBS. M1-γ2 aDBS in parkinsonian monkeys resulted in clinical benefits that did not exceed those from cDBS. However, M1-γ2 aDBS achieved this magnitude of benefit for only two thirds of the charge delivered by cDBS. In conclusion, M1-γ2 aDBS is an effective therapeutic approach which requires a lower electrical charge delivery than cDBS for comparable clinical benefits.

Abstract Objectives: Transcranial magnetic stimulation (TMS) has been widely used to modulate brain activity in healthy and diseased brains, but the underlying mechanisms are not fully understood. Previous research leveraged biophysical modeling of the induced electric field (E-field) to map causal structure-function relationships in the primary motor cortex. This study aims at transferring this localization approach to spatial attention, which helps to understand the TMS effects on cognitive functions, and may ultimately optimize stimulation schemes. Approach: Thirty right-handed healthy participants underwent a functional magnetic imaging (fMRI) experiment, and seventeen of them participated in a TMS experiment. The individual fMRI activation peak within the right inferior parietal lobule (rIPL) during a Posner-like attention task defined the center target for TMS. Thereafter, participants underwent 500 Posner task trials. During each trial, a 5-pulse burst of 10 Hz repetitive TMS (rTMS) was given over the rIPL to modulate attentional processing. The TMS-induced E-fields for every cortical target were correlated with the behavioral modulation to identify relevant cortical regions for attentional orientation and reorientation. Main results: We did not observe a robust correlation between E-field strength and behavioral outcomes, highlighting the challenges of transferring the localization method to cognitive functions with high neural response variability and complex network interactions. Nevertheless, TMS selectively inhibited attentional reorienting in five out of seventeen subjects, resulting in task-specific behavioral impairments. The BOLD-measured neuronal activity and TMS-evoked neuronal effects showed different patterns, which emphasizes the principal distinction between the neural activity being correlated with (or maybe even caused by) particular paradigms, and the activity of neural populations exerting a causal influence on the behavioral outcome. Significance: This study is the first to explore the mechanisms of TMS-induced attentional modulation through electrical field modeling. Our findings highlight the complexity of cognitive functions and provide a basis for optimizing attentional stimulation protocols.

Monopiles are the predominant type of foundation used for offshore wind turbines. The increase in size of monopiles and the stricter environmental regulations in terms of underwater noise levels has motivated the development of alternatives to the conventional impact-driving method of monopile installation. One of the alternatives is the (axial) vibratory installation, which has been previously studied in field [1, 2, 4] and laboratory [3, 5] conditions. However, there is limited knowledge on the effects of vibratory installation (and how these effects differ from those caused by impact-driving) on the lateral response of monopiles. This extended abstract presents the results of an ongoing Join Industry Project (SIMOX – Sustainable Installation of XXL Monopiles) which aims at comparing different installation methods from the point of view of driveability, noise emissions and lateral response. The present abstract particularly focuses on the lateral response of monopiles. As a first step towards the large-scale onshore field tests to be executed in 2023, a laboratory study was conducted at the Water-Soil Flume at Deltares, in Delft (NL), which consists of a tank with 9.0 m of length, 5.5 m of width and 2.5 m of depth, with a multipurpose wagon on rails above it (Figure 1). The tank was filled with saturated Sibelco S90 sand up to a height of 2.4 m in compacted layers of 50 cm. The experimental programme consisted of 4 batches (batches 1, 2 and 3 with dense sand and batch 4 with medium-dense sand) in which piles of diameter D = 32 cm, embedded length L = 1.5 m and wall thickness t = 4 mm or 10 mm were installed and loaded laterally. While batch 1 focused on driveability aspects, in the other three batches 8 piles were installed (per batch) and subsequently subjected to lateral loading. The centre-to-centre distance between piles was 8D in the loading direction and 6.5D perpendicular to the loading direction. The distance between the piles and walls of the tank was 4.3D. All distances were larger than the minimum distances recommended in the literature [6]. The piles were installed with two different methods: vibratory-driven, using a hydraulic vibro-hammer APE-23 with an eccentric moment of 1.3 kg.m, and impact-driven, using a dropping weight impact-hammer HL750. For each method, selected installation parameters were varied, namely the vibratory frequency and lowering speed of the crane for vibrated piles, and dropping mass and fall height for the impact-driven piles. Lateral loading was applied at the pile head by means of an in-house built lateral loading device consisting of an electric motor connected to a spindle. The lateral displacements were measured by a magnetostrictive linear position sensor, independent of the lateral loading system. The loading regime consisted of an initial monotonic loading up to 25% of Hult (where Hult is defined as the load at which the pile exhibits a displacement of 0.1D at ground level – obtained from 3D FE analyses), followed by cyclic loading (1000 cycles for most piles) and a final monotonic stage up to the maximum load. The different combinations of lowering speeds of the crane (low, high) with the different frequencies of the vibro-hammer (low, high) led to different types of vibratory installation: crane controlled or free hanging. Under crane-controlled installation, the full weight of the pile-hammer system is sustained by the overhead crane, hence the crane load measured by a load cell oscillates around the static weight of the pile-hammer system. Under free-hanging conditions, on the other hand, the load taken by the crane is zero, meaning that the weight of the pile-hammer system is fully taken by the soil – both by shaft friction and tip resistance. The results in dense sand showed that the initial monotonic response of the piles is affected by the vibration mode, and not by the installation frequency or penetration speed alone. While the crane-controlled vibrated piles exhibited lateral stiffness similar (i.e. slightly lower) to the impact-driven piles, the free-hanging vibrated piles showed markedly lower lateral stiffness compared to the other piles. The softer behaviour observed for these piles could be attributed to various reasons, such as the difficulty in controlling the pile verticality during installation. For all free hanging piles, inclination was observed approximately half-way through installation, which was corrected in the final part of installation. The exact inclination during installation was not measured, which will be done in the onshore field tests. The test results showed, however, that during cyclic loading the differences in lateral stiffness decrease, i.e. the softest piles in the initial monotonic stage were the ones that exhibited the largest gain in lateral cyclic stiffness, whereas the stiffest piles in the initial loading stage were the ones with the smallest increase in stiffness during cyclic loading.

Background: Reperfusion following ischemia can lead to more injuries than ischemia itself especially in diabetic patients. The aim of this study was to evaluate the effect of dexmedetomidine on ischemia-reperfusion injury (IRI) in rats with have hepatic IRI and diabetes mellitus. Methodology: Twenty-eight Wistar Albino rats were randomised into four groups as control (C), diabetic (DC), diabetic with hepatic ischemia-reperfusion injury (DIR), and diabetic but administered dexmedetomidine followed by hepatic IRI (DIRD) groups. Hepatic tissue samples were evaluated histopathologically by semiquantitative methods. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathion s-transpherase (GST), and catalase (CAT) enzyme levels were investigated in liver and kidney tissues as oxidative state parameters. Results: In Group DIR; hepatocyte degeneration, sinusoidal dilatation, pycnotic nucleus, and necrotic cells were found to be more in rat hepatic tissue; while mononuclear cell infiltration was higher in the parenchyme. MDA levels were significantly lower; but SOD levels were significantly higher in Group DIRD with regard to Group DIR. In the IRI induced diabetic rats’ hepatic and nephrotic tissues MDA levels, showing oxidative injury, were found to be lower. SOD levels, showing early antioxidant activity, were higher. Conclusion: The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease IRI. Key words: Hepatic ischemia reperfusion injury; Diabetes mellitus; Dexmedetomidine; Rat; MDA; SOD Citation: Sezen SC, Işık B, Bilge M, Arslan M, Çomu FM, Öztürk L, Kesimci E, Kavutçu M. Effect of dexmedetomidine on ischemia-reperfusion injury of liver and kidney tissues in experimental diabetes and hepatic ischemia-reperfusion injury induced rats. Anaesth Pain & Intensive Care 2016;20(2):143-149 Received: 21 November 2015; Reviewed: 10, 24 December 2015, 9, 10 June 2016; Corrected: 12 December 2015; Accepted: 10 June 2016 INTRODUCTİON Perioperative acute tissue injury induced by ischemia-reperfusion is a comman clinical event caused by reduced blood supply to the tissue being compromised during major surgery. Ischemia leads to cellular injury by depleting cellular energy deposits and resulting in accumulation of toxic metabolites. The reperfusion of tissues that have remained in ischemic conditions causes even more damage.1 Furthermore hepatic ischemia-reperfusion injury (IRI) demonstrates a strong relationship with peri-operative acute kidney injury.2 The etiology of diabetic complications is strongly associated with increased oxidative stress (OS). Diabetic patients are known to have a high risk of developing OS or IRI which results with tissue failure.3 The most important role in ischemia and reperfusion is played by free oxygen radicals.1 In diabetes, characterized by hyperglycemia, even more free oxygen radicals are produced due to oxidation of glucose and glycosylation of proteins.3 The structures which are most sensitive to free oxygen radicals in the cells are membrane lipids, proteins, nucleic acids and deoxyribonucleic acids.1 It has been reported that endogenous antioxidant enzymes [superoxide dismutase (SOD), glutathion s-transpherase (GST), catalase (CAT)] play an important role to alleviate IRI.4-8 Also some pharmacological agents have certain effects on IRI.1 The anesthetic agents influence endogenous antioxidant systems and free oxygen radical formation.9-12 Dexmedetomidine is a selective α-2 adrenoceptor agonist agent. It has been described as a useful and safe adjunct in many clinical applications. It has been found that it may increase urine output by considerably redistributing cardiac output, inhibiting vasopressin secretion and maintaining renal blood flow and glomerular filtration. Previous studies demonstrated that dexmedetomidine provides protection against renal, focal cerebral, cardiac, testicular, and tourniquet-induced IRI.13-18 Arslan et al observed that dexmedetomidine protected against lipid peroxidation and cellular membrane alterations in hepatic IRI, when given before induction of ischemia.17 Si et al18 demonstrated that dexmedetomidine treatment results in a partial but significant attenuation of renal demage induced by IRI through the inactivation of JAK/STAT signaling pathway in an in vivo model. The efficacy of the dexmedetomidine for IRI in diabetic patient is not resarched yet. The purpose of this experimental study was to evaluate the biochemical and histological effects of dexmedetomidine on hepatic IRI in diabetic rat’s hepatic and renal tissue. METHODOLOGY Animals and Experimental Protocol: This study was conducted in the Physiology Laboratory of Kirikkale University upon the consent of the Experimental Animals Ethics Committee of Kirikkale University. All of the procedures were performed according to the accepted standards of the Guide for the Care and Use of Laboratory Animals. In the study, 28 male Wistar Albino rats, weighing between 250 and 300 g, raised under the same environmental conditions, were used. The rats were kept under 20-21 oC at cycles of 12-hour daylight and 12-hour darkness and had free access to food until 2 hours before the anesthesia procedure. The animals were randomly separated into four groups, each containing 7 rats. Diabetes was induced by a single intraperitoneal injection of streptozotocin (Sigma Chemical, St. Louis, MO, USA) at a dose of 65 mg/kg body weight. The blood glucose levels were measured at 72 hrs following this injection. Rats were classified as diabetic if their fasting blood glucose (FBG) levels exceeded 250 mg/dl, and only animals with FBGs of > 250 mg/dl were included in the diabetic groups (dia­betes only, diabetes plus ischemia-reperfusion and diabetes plus dexmedetomidine-ischemia-reperfusion). The rats were kept alive 4 weeks after streptozotocin injection to allow development of chronic dia­betes before they were exposed to ischemia-reperfusion.(19) The rats were weighed before the study. Rats were anesthetized with intraperitoneal ketamine 100 mg/kg. The chest and abdomen were shaved and each animal was fixed in a supine position on the operating table. The abdomen was cleaned with 1% polyvinyl iodine and when dry, the operating field was covered with a sterile drape and median laparotomy was performed. There were four experimental groups (Group C (sham-control; n = 7), (Group DC (diabetes-sham-control; n = 7), Group DIR (diabetes-ischemia-reperfusion; n = 7), and Group DIRD (diabetes-ischemia-reperfusion-dexmedetomidine; n = 7). Sham operation was performed on the rats in Group C and Group DC. The sham operation consisted of mobilization of the hepatic pedicle only. The rats in this group were sacrificed 90 min after the procedure. Hepatic I/R injury was induced in Groups DIR and DIRD respectively with hepatic pedicle clamping using a vascular clamp as in the previous study of Arslan et al.(17) After an ischemic period of 45 min, the vascular clamp was removed. A reperfusion period was maintained for 45 min. In Group DIRD, dexmedetomidine hydrochloride 100 μg/kg, (Precedex 100 μg/2 ml, Abbott®, Abbott Laboratory, North Chicago, Illinois, USA) was administrated via intraperitoneal route 30 minutes before surgery. All the rats were given ketamine 100 mg/kg intraperitoneally and intracardiac blood samples were obtained. Preserving the tissue integrity by avoiding trauma, liver and renal biopsy samples were obtained. Biochemical Analysis: The liver and renal tissues were first washed with cold deionized water to discard blood contamination and then homogenized in a homogenizer. Measurements on cell contest require an initial preparation of the tissues. The preparation procedure may involve grinding of the tissue in a ground glass tissue blender using a rotor driven by a simple electric motor. The homogenizer as a tissue blender similar to the typical kitchen blender is used to emulsify and pulverize the tissue (Heidolph Instruments GMBH & CO KGDiax 900 Germany®) at 1000 U for about 3 min. After centrifugation at 10,000 g for about 60 min, the upper clear layer was taken. MDA levels were determined using the method of Van Ye et al,(20) based on the reaction of MDA with thiobarbituric acid (TBA). In the TBA test reaction, MDA and TBA react in acid pH to form a pink pigment with an absorption maximum at 532 nm. Arbitrary values obtained were compared with a series of standard solutions (1,1,3,3-tetraethoxypropane). Results were expressed as nmol/mg.protein. Part of the homogenate was extracted in ethanol/chloroform mixture (5/3 v/v) to discard the lipid fraction, which caused interferences in the activity measurements of T-SOD, CAT and GST activities. After centrifugation at 10.000 x g for 60 min, the upper clear layer was removed and used for the T-SOD, CAT, GST enzyme activity measurement by methods as described by Durak et al21, Aebi22 and Habig et al23 respectively. One unit of SOD activity was defined as the enzyme protein amount causing 50% inhibition in NBTH2 reduction rate and result were expressed in U/mg protein. The CAT activity method is based on the measurement of absorbance decrease due to H2O2 consumption at 240 nm. The GST activity method is based on the measurement of absorbance changes at 340 nm due to formation of GSH-CDNB complex. Histological determinations: Semiquantitative evaluation technique used by Abdel-Wahhab et al(24) was applied for interpreting the structural changes investigated in hepatic tissues of control and research groups. According to this, (-) (negative point) represents no structural change, while (+) (one positive point) represents mild, (++) (two positive points) medium and (+++) (three positive points) represents severe structural changes. Statistical analysis: The Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA) 20.0 softwre was used for the statistical analysis. Variations in oxidative state parameters, and histopathological examination between study groups were assessed using the Kruskal-Wallis test. The Bonferroni-adjusted Mann-Whitney U-test was used after significant Kruskal-Wallis to determine which groups differed from the others. Results were expressed as mean ± standard deviation (Mean ± SD). Statistical significance was set at a p value < 0.05 for all analyses. RESULTS There was statistically significant difference observed between the groups with respect to findings from the histological changes in the rat liver tissue (hepatocyte degeneration, sinüsoidal dilatation, pycnotic nucleus, prenecrotic cell) determined by light microscopy according to semiquantitative evaluation techniques (p < 0.0001). In Group DIR, hepatocyte degeneration was significantly high compared to Group C, Group DC and Group DIRD (p < 0.0001, p < 0.0001, p = 0.002, respectively), (Table 1, Figure 1-4). Similarly, sinüsoidal dilatation was significantly higher in Group DIR (p < 0.0001, p = 0.004, p = 0.015, respectively). Although, pcynotic nucleus was decreased in Group DIRD, it did not make a significant difference in comparison to Group DIR (p = 0.053), (Table 1, Figure 1-4). The prenecrotic cells were significantly increased in Group DIR, with respect to Group C, Group DC and Group DIRD (p < 0.0001, p = 0.004, p < 0.0001, respectively), (Table 1, Figure 1-4). Table 1. The comparison of histological changes in rat hepatic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR Figure 1: Light microscopic view of hepatic tissue of Group C (control). VC: vena centralis, *: sinusoids. ®: hepatocytes, k: Kupffer cells, G: glycogen granules, mc: minimal cellular changes, Hematoxilen & Eosin x 40 Figure 2: Light-microscopic view of hepatic tissue of Group DC (diabetes mellitus control) (G: Glycogen granules increased in number, (VC: vena centralis, *:sinusoids. ®:hepatocytes, k:Kupffer cells, G: glycogen granules, mc: minimal cellular changes; Hematoxylin & Eosin x 40) Figure 3: Light-microscopic view of hepatic tissue of Group DIR (Diabetes Mellitus and ischemia-reperfusion) (VC: vena centralis, (H) degenerative and hydrophic hepatocytes, (dej) vena centralis degeneration (centrolobar injury) (*): sinusoid dilatation. (←) pycnotic and hyperchromatic nuclei, MNL: mononuclear cell infiltration, (¯) congestion, K: Kupffer cell hyperplasia, (­) vacuolar degeneration (Hematoxylin & Eosin x 40) Figure 4: Light-microscopic view of hepatic tissue of Group DIRD (Diabetes Mellitus and ischemia-reperfusion together with dexmedetomidine applied group) (VC: vena centralis, (MNL) mononuclear cell infiltration, (dej) hydrophilic degeneration in hepatocytes around vena centralis, (conj) congestion, G: glycogen granules, (←) pycnotic and hyperchromatic nuclei, sinusoid dilatation (*) (Hematoxylin & Eosin x 40) Besides, in liver tissue parenchyma, MN cellular infiltration was a light microscopic finding; and showed significant changes among the groups (p < 0.0001). This was significantly higher in Group DIR, compared to Group C, DC, and DIRD (p < 0.0001, p=0.007, p = 0.007, respectively), (Table 1, Figure 1-4). The enzymatic activity of MDA, SOD and GST in hepatic tissues showed significant differences among the groups [(p = 0.019), (p = 0.034). (p = 0.008) respectively]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p = 0.011, p = 0.016, respectively), (Table 2). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.010, p = 0.038, respectively), (Table 2). The GST enzyme activity was significantly higher in Group DIR, when compared to Group C, DC and DIRD (p = 0.007, p = 0.038, p = 0.039, respectively), (Table 2). Table 2. Oxidative state parameters in rat hepatic tissue [Mean ± SD] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR The enzymatic activity of MDA, SOD in renal tissues, showed significant differences among the groups [(p < 0.0001), (p = 0.008) respectively ]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p < 0.0001, p < 0.0001, respectively). Also MDA enzyme activity level was significantly increased in Group DC, in comparison to Group C and Group DIRD (p = 0.003, p = 0.001, respectively), (Table 3). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.032, p = 0.013, respectively), (Table 3). The GST enzyme activity was significantly higher in Group DIR than the other three groups, however; CAT levels were similar among the groups (Table 3). Table 3: Oxidative state parameters in rat nephrotic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR DISCUSSION In this study, we have reported the protective effect of dexmedetomidine in experimental hepatic and renal IRI model in the rat by investigating the MDA and SOD levels biochemically. Besides, hepatic histopathological findings also supported our report. Ischemic damage may occur with trauma, hemorrhagic shock, and some surgical interventions, mainly hepatic and renal resections. Reperfusion following ischemia results in even more injury than ischemia itself. IRI is an inflammatory response accompanied by free radical formation, leucocyte migration and activation, sinusoidal endothelial cellular damage, deteoriated microcirculation and coagulation and complement system activation.1 We also detected injury in hepatic and renal tissue caused by reperfusion following ischemia in liver. Experimental and clinical evidence indicates that OS is involved in both the pathogenesis and the complications of diabetes mellitus.25,26 Diabetes mellitus is a serious risk factor for the development of renal and cardiovascular disease. It is also related to fatty changes in the liver.27 Diabetes-related organ damage seems to be the result of multiple mechanisms. Diabetes has been associated with increased free radical reactions and oxidant tissue damage in STZ-induced diabetic rats and also in patients.26Oxidative stress has been implicated in the destruction of pancreatic β-cells28 and could largely contribute to the oxidant tissue damage associated with chronic hyperglycemia.29 A number of reports have shown that antioxidants can attenuate the complications of diabetes in patients30 and in experimental models.28,31 This study demonstrated that diabetes causes a tendency to increase the IRI. There is a lot of investigations related to the pharmacological agents or food supplements applied for decreasing OS and IRI. Antioxidant agents paly an important role in IRI by effecting antioxidant system or lessening the formation of ROS. It has been reported that anesthetic agents too, are effective in oxidative stress.1 During surgical interventions, it seems rational to get benefit from anesthetic agents in prevention of OS caused by IRI instead of using other agents. It has been declared that; dexmedetomidine; as an α-2 agonist with sedative, hypnotic properties; is important in prevention of renal, focal, cerebral, cardiac, testicular and tourniquet-induced IRI.13-18 On the other hand Bostankolu et al. concluded that dexmedetomidine did not have an additional protective role for tournique induced IRI during routine general anesthesia.32 In this study; we have shown that dexmedetomidine has a reducing effect in IRI in diabetic rats. Some biochemical tests and histopathological evaluations are applied for bringing up oxidative stress and IRI in the tissues. Reactive oxygen species (ROS) that appear with reperfusion injury damage cellular structures through the process of the lipid peroxidation of cellular membranes and yield toxic metabolites such as MDA.33 As an important intermidiate product in lipid peroxidation, MDA is used as a sensitive marker of IRI.34 ROS-induced tissue injury is triggered by various defense mechanisms.35 The first defence mechanisms include the antioxidant enzymes of SOD, CAT, and GPx. These endogenous antioxidants are the first lines of defence against oxidative stres and act by scavenging potentially damaging free radical moieties.36 There is a balance between ROS and the scavenging capacity of antioxidant enzymes.1-8 In this study, for evaluation of oxidative damage and antioxidant activity, MDS, SOD, GST and CAT levels were determined in liver and kidney tissues. MDA levels in hepatic and renal tissues were higher in Group DIR compared to Group C and Group DIRD. GST levels were higher in Group DIR compared to all the other three groups. When the groups were arranged from highest to lowest order, with respect to CAT levels, the order was; Group DIR, Group DIRD, Group DC and Group C. However, the difference was not significant. The acute phase reactant MDA, as a marker of OS, was found to be high in Group DIR and low in Group DIRD. This could be interpreted as the presence of protective effect of dexmedetomidine in IRI. IRI developing in splanchnic area causes injury also in the other organs.35 Leithead et al showed that clinically significant hepatic IRI demonstrates a strong relationship with peri-operative acute kidney injury.2 In our experimental research that showed correlation to that of research by Leithead et al. After hepatic IRI in diabetic rats renal OS marker MDA levels were significantly more in Group DIR than Group DIRD. In our study, we observed histopathological changes in the ischemic liver tissue and alterations in the level of MDA, SOD, GST and CAT levels which are OS markers. Histopathological changes of the liver tissues are hepatocyt degeneration, sinusoidal dilatation, nuclear picnosis, celluler necrosis, mononuclear cell infiltrationat paranchimal tissue. These histopathological injury scores were significantly lower in the Group DIRD than those in group DIR. LIMITATION Study limitation is there was no negative control group, as this type of surgical intervention is not possible in rats without anesthesia. CONCLUSION The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease ischemia-reperfusion injury. Conflict of interest and funding: The authors have not received any funding or benefits from industry or elsewhere to conduct this study. Author contribution: ŞCS: Concept, conduction of the study work and manuscript editing; BI: the main author to write the article; MB & MK: biochemical analysis; MA: manuscript writing; FMÇ: helped us with experimental study; LÖ & EK: collection of data REFERENCES Collard CD, Gelman S. Pathophysiology, clinical manifestations, and prevention of ischemia-reperfusion injury. Anesthesiology. 2001;94(6):1133. [PubMed] [Free full text] Leithead JA, Armstrong MJ, Corbett C, Andrew M, Kothari C, Gunson BK, et al. Hepatic ischemia reperfusion injury is associated with acute kidney injury following donation after brain death liver transplantation. Transpl Int. 2013;26(11):1116. doi: 10.1111/tri.12175. [PubMed] [Free full text] Panés J, Kurose I, Rodriguez-Vaca D, Anderson DC, Miyasaka M, Tso P, et al. Diabetes exacerbates inflammatory responses to ischemia-reperfusion. Circulation. 1996;93(1):161. [PubMed] [Free full text] Touyz RM. Reactive oxygen species and angiotensin II signaling in vascular cells-implications in cardiovascular disease. Braz J Med Biol Res. 2004;37:1263. [PubMed] [Free full text] Olivares-Corichi IM, Ceballos G, Ortega-Camarillo C, Guzman-Grenfell AM, Hicks JJ. Reactive oxygen species (ROS) induce chemical and structural changes on human insulin in vitro, including alterations in its immunoreactivity. Front Biosci. 2005;10:834. [PubMed] Witko-Sarsat V, Friedlander M, Capeillere-Blandin C, Nguyen-Khoa T, Nguyen AT, Zingraff J, et al. Advanced oxidation protein products as a novel marker of oxidative stress in uremia. Kidney Int. 1996;49:1304. [PubMed] Harman D. Free radical theory of aging: An update: Increasing the functional life span. Ann N Y Acad Sci. 2006;1067:10. [PubMed] Nita DA, Nita V, Spulber S, Moldovan M, Popa DP, Zagrean AM, Zagrean L. Oxidative damage following cerebral ischemia depends on reperfusion – a biochemical study in rat. J Cell Mol Med. 2001;5:163–170. [PubMed] [Free full text] Annecke T, Kubitz JC, Kahr S, Hilberath JM, Langer K, Kemming GI, et al. Effects of sevoflurane and propofol on ischaemia-reperfusion injury after thoracic-aortic occlusion in pigs. Br J Anaesth. 2007;98(5):581. [PubMed] [Free full text] De Hert SG, Van der Linden PJ, Cromheecke S, Meeus R, Nelis A, Van Reeth V, ten Broecke PW, et al. Cardioprotective properties of sevoflurane in patients undergoing coronary surgery with cardiopulmonary bypass are related to the modalities of its administration. Anesthesiology. 2004;101(2):299. [PubMed] [Free full text] Yuzer H, Yuzbasioglu MF, Ciralik H, Kurutas EB, Ozkan OV, Bulbuloglu E, et al. Effects of intravenous anesthetics on renal ischemia/reperfusion injury. Ren Fail. 2009;31(4):290. [PubMed] [Free full text] Lee HT, Ota-Setlik A, Fu Y, Nasr SH, Emala CW. Differential protective effects of volatile anesthetics against renal ischemia-reperfusion injury in vivo. Anesthesiology. 2004;101(6):1313. [PubMed] [Free full text] Lai YC, Tsai PS, Huang CJ. Effects of dexmedetomidine on regulating endotoxin-induced up-regulation of inflammatory molecules in murine macrophages. J Surg Res. 2009;154(2):212. doi: 10.1016/j.jss.2008.07.010. [PubMed] Yoshitomi O, Cho S, Hara T, Shibata I, Maekawa T, Ureshino H, Sumikawa K. Direct protective effects of dexmedetomidine against myocardial ischemia-reperfusion injury in anesthetized pigs. Shock. 2012;38(1):92. doi: 10.1097/SHK.0b013e318254d3fb. [PubMed] Jolkkonen J, Puurunen K, Koistinaho J, Kauppinen R, Haapalinna A, Nieminen L, et al. Neuroprotection by the alpha2-adrenoceptor agonist, dexmedetomidine, in rat focal cerebral ischemia. Eur J Pharmacol. 1999;372(1):31. [PubMed] Kocoglu H, Ozturk H, Ozturk H, Yilmaz F, Gulcu N. Effect of dexmedetomidine on ischemia-reperfusion injury in rat kidney: a histopathologic study. Ren Fail. 2009;31(1):70. doi: 10.1080/08860220802546487. [PubMed] Arslan M, Çomu FM, Küçük A, Öztürk L, Yaylak F. Dexmedetomidine protects against lipid peroxidation and erythrocyte deformability alterations in experimental hepatic ischemia reperfusion injury. Libyan J Med. 2012;7. doi: 10.3402/ljm.v7i0.18185 [PubMed] [Free full text] Si Y, Bao H, Han L, Shi H, Zhang Y, Xu L, et al. Dexmedetomidine protects against renal ischemia and reperfusion injury by inhibiting the JAK/STAT signaling activation. J Transl Med. 2013;11(1):141. doi: 10.1186/1479-5876-11-141. [PubMed][Free full text] Türeci E, İş M, Üzüm G, Akyüz F, Ulu MO, Döşoğlu M, et al. Alterations in blood-brain barrier after traumatic brain injury in streptozotocin-induced diabetic rats. J Nervous Sys Surgery 2009;2(2):79. [Free full text] Van Ye TM, Roza AM, Pieper GM, Henderson J Jr, Johnson JP, Adams MB. Inhibition of intestinal lipid peroxidation does not minimize morphological damage. J Surg Res 1993;55:553. [PubMed] Durak I, Canbolat O, Kavutcu M, Öztürk HS, Yurtarslanı Z. Activities of total, cytoplasmic and mihochondrial superoxide dismutase enzymes in sera and pleural fluids from patient with lung cancer. J Clin Lab Anal 1996;10:17. [PubMed] Aebi H. Catalase. In: H.U.Bergmeyer (Ed): Methods of Enzymatic Analysis, Academic Press , New York and London, 1974;pp.673-677. Habig WH, Pabst MJ, Jakoby WB. Glutathione S-transferases. The first enzymatic step in mercapturic acid formation. J Biol Chem 1974;249:7130. [PubMed] [Free full text] Abdel-Wahhab MA, Nada SA, Arbid MS. Ochratoxicosis: Prevention of developmental toxicity by L-methionine in rats. J Appl Toxicol 1999;19:7. [PubMed] Wolff SP. Diabetes mellitus and free radicals: free radicals, transition metals and oxidative stress in the aetiology of diabetes mellitus and complications. Br Med Bull. 1993;49:642. [PubMed] [Free full text] West IC. Radicals and oxidative stress in diabetes. Diabet Med. 2000;17:171–180. [PubMed] Wanless IR, Lentz JS. Fatty liver hepatitis (steatohepatitis) and obesity: an autopsy study with analysis risk factors. Hepatology. 1990;12:1106. [PubMed] Hotta M, Tashiro F, Ikegami H, Niwa H, Ogihara T, Yodoi J, Miyazaki J. Pancreatic cell-specific expression of thioredoxin, an antioxidative and antiapoptotic protein, prevents autoimmune and streptozotocin-induced diabetes. J Exp Med. 1998;188:1445. [PubMed] [Free full text] Baynes JW. Role of oxidative stress in the development of complications in diabetes. Diabetes. 1991;40:405. [PubMed] Borcea V, Nourooz-Zadeh J, Wolff SP, Klevesath M, Hofmann M, Urich H, et al. α-Lipoic acid decreases oxidative stress even in diabetic patients with poor glycemic control and albuminuria. Free Radic Biol Med. 1999;26:1495. [PubMed] Fitzl G, Martin R, Dettmer D, Hermsdorf V, Drews H, Welt K. Protective effect of ginkgo biloba extract EGb 761 on myocardium of experimentally diabetic rats, I: ultrastructural and biochemical investigation on cardiomyocytes. Exp Toxicol Pathol. 1999;51:189. [PubMed] Bostankolu E, Ayoglu H, Yurtlu S, Okyay RD, Erdogan G, Deniz Y, et al. Dexmedetomidine did not reduce the effects of tourniquet-induced ischemia-reperfusion injury during general anesthesia. Kaohsiung J Med Sci. 2013;29(2):75. doi: 10.1016/j.kjms.2012.08.013. [PubMed] [Free full text] Wakai A, Wang JH, Winter DC, Street JT, O’Sullivan RG, Redmond HP. Tourniquet-induced systemic inflammatory response in extremity surgery. J Trauma 2001;51:922. [PubMed] Concannon MJ, Kester CG, Welsh CF, Puckett CL. Patterns of free-radical production after tourniquet ischemia implications for the hand surgeon. Plast Reconstr Surg 1992;89:846. [PubMed] Grisham MB, Granger DN. Free radicals: reactive metabolites of oxygen as mediators of postischemic reperfusion injury. In: Martson A, Bulkley GB, Fiddian-Green RG, Haglund U, editors. Splanchnic İschemia and Multiple Organ Failure. St Louis, MO: Mosby;1989. pp. 135–144. Mccard JM. The evolution of free radicals and oxidative stress. Am J Med 2000;108:652. [PubMed]