Search

This paper introduces a multifunction interactive PV system that has the ability to feed a nonlinear local load in either grid-tied topology (GTT) or off-grid topology (OGT) and transits between the two topologies are seamless. The interactive PV system utilizes a sliding Fourier transform-based phase-locked loop (SFT-PLL) as an adaptive and robust control technique for extracting the fundamental load current. Further, the SFT-PLL is also used to synchronize the inverter output voltage with the grid during the GTT. The proposed synchronization technique has a superior immunity to the weak grid problems. The SFT-PLL based control technique has a very good ability to mitigate the nonlinear load harmonics and to deliver active current to the grid with a unity power factor. Moreover, the proposed control technique is able to keep a balanced grid current when the connected load is unbalanced whether the PV source is available or not. The DC-link voltage is controlled by the controller of the voltage source inverter (VSI) during GTT. During the OGT, the AC load voltage is regulated by the VSI controller while the DC-link voltage is regulated by the boost converter controller to satisfy the power requirements of the connected load. The simulation and experimental results show the effectiveness of the proposed control technique in feeding a balanced current with THD adheres to the IEEE-519 standard at different operating conditions. The performance of the proposed method is compared with recently published adaptive filtering techniques to show its effectiveness especially when the load current has a DC-offset.

This article presents a robust simplified dynamic observer-based backstepping control (RSDO-BSC) and direct torque control (DTC) synthesized with duty cycle control strategy of a six-phase induction motor (6PIM) for marine vessels applications. RSDO-BSC and DTC are employed to estimate the rotor speed, while the DTC is utilized to accomplish enhanced steady-state torque performance via accurate inputs applied to the switching table of the six-phase inverter. Furthermore, by using the duty cycle control approach, the loss components in the subspace are disregarded via the appropriate choice of virtual voltage vectors. Consequently, the 6PIM torque ripples and the current harmonics are significantly reduced. First, both the flux and the torque are decoupled using Lyapunov theory on a 6PIM two-axis mathematical model represented in the stationary reference frame. The 6PIM actual stator voltages are acquired from the dc-link voltage via the space vector pulsewidth modulated inverter. Subsequently, when the 6PIM is loaded under the rated speed, a rapid search approach is used to maximize the 6PIM efficiency. A 750-W 6PIM drive test setup employs a dSPACE 1104 for real-time implementation. The proposed RSDO-BSC performance is experimentally investigated at different speed commands, load disturbance, and low speed command with low load torque conditions.

This paper presents a hardware implementation of flexible and low-cost attitude determination and control system (ADCS) for two-axis-stabilized CubeSat. As small satellite missions are increasing, the CubeSat requires precise ADCS with attitude drift adjustment. This attitude drift if not properly compensated, will cause a slow attitude information loss as the error in attitude rises between the actual and estimated signals. The proposed ADCS comprises two steps; the attitude determination which estimates the current CubeSat’s attitude and a novel simplified intelligent proportional-integral control algorithm that accurately adjusts the attitude. The control algorithm is based on the multi degree-of-freedom controller concept and has no controller gains parameters. The proposed ADCS employs sun sensor, magnetometer, and a micro-electro-mechanical gyroscope sensor to correct the attitude drift by offering a comparative attitude that is utilized for updating the estimated attitude delivered to the Kalman filter for determining the CubeSat’s attitude and angular velocity. The ADCS model verification and validation are accomplished via Matlab/Simulink and hardware implementation. A comparison with other ADCS techniques is presented. The ADCS simulated model demonstrates precision results with error of less than 0.1°.

This paper presents the design and implementation of a novel low-cost speed sensorless control technique for a permanent magnet assisted synchronous reluctance motor (PMa-SynRM). A robust adaptive speed (RAS) observer is designed for estimating the rotor speed and position, respectively. The RAS observer estimates the PMa-SynRM speed and position from the back electromotive force space-vector determination without voltage sensors by using the reference voltages issued from the current controllers instead of the actual ones. The novelty of the proposed RAS estimation technique is the adaptation of the feedback error of the actual values. Thus, the proposed observer structure promises a higher degree of robustness against PMa-SynRM parameter changes in the sensitivity analysis presented in this paper. The dynamic model and experimental realizations of the proposed control technique are introduced. A 6-kW PMa-SynRM drive test setup is constructed including a dSPACE 1104 board as the control heart of the proposed system. The hardware-in-the-loop Typhoon HIL 402 device is used to experimentally emulate the PMa-SynRM and the inverter connected to a dSPACE MicroLabBox. The proposed RAS observer robustness is evaluated using a HIL model and experimental results under different conditions. A comparative experimental analysis between the proposed RAS and Luenberger observers has been performed.

This paper presents an optimized design in the permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) rotor structure design with hybrid adopted materials for enhancing the motor characteristics and operation. Two types of permanent magnet (PM) materials are embraced in the PMa-SynRM rotor of rare-earth and ferrite PMs. The optimized design for the PMa-SynRM rotor structure considers the motor magnetic equivalent circuit for reducing the reluctance of the hybrid PMs to improve the motor performance. Moreover, the irreversible demagnetization of the ferrite PM which occurs due to the reversing of the magnetic field of the rare-earth PM is presented. The analytical rotating losses computation with the hybrid adopted materials at the design process is introduced. The rotating losses of the PMa-SynRM are investigated as core, magnet, proximity, ohmic, and friction losses. The core loss in the PMa-SynRM occurs due to the altering of the flux densities in numerous fragments of the iron structures. The loss measurements can be accomplished by measuring the electric parameters of the PMa-SynRM at a defined operating point. The magnetic modeling of the improved 6 KW PMa-SynRM manufactured prototype structure is derived and rotational losses are computed, validated, and compared with the finite element analysis (FEA).

The hardware-in-the-loop (HIL) realization platform significantly supports the advance of control techniques in secure, precise, and low-cost design. Innovative control techniques are anticipated to ensure aerospace vehicle drive controllability. This paper presents a novel robust discrete-time (RDT) predictive current control (PCC) strategy of a permanent-magnet-assisted synchronous reluctance motor (PMa-SynRM) implemented using the HIL tool and the experimental setup. The proposed RDT controller has a discrete-time integral term added to the conventional deadbeat (DB) current predictive control to improve the robustness and stability of the current control. The PMa-SynRM mathematical model with parameter uncertainties is theoretically derived. Conventional PCC techniques are constructed utilizing the DB framework. Although this controller has a good dynamic response, it still suffers from unmodeled transient changes as well as parametric motor uncertainties. A 6-kW PMa-SynRM machine drive system is built and tested using DS1104 R&D Controller Board. Typhoon HIL is used to emulate the PMa-SynRM and the inverter connected to a dSPACE MicroLabBox. The performance of the proposed RDT technique is assessed and compared with traditional DB using the HIL and experimental results under different speed commands, electrical and mechanical motor parameters variations, and rated speed reversal conditions.

This paper proposes an optimal adaptive super-twisting sliding-mode control (OASTSMC) via adaptive dynamic programming (ADP) to achieve high precision-positioning for linear stage considering the uncertain nonlinear dynamics of the permanent-magnet synchronous motor (PMSM) servo drive actuator. First, the position of the linear-stage is stabilized through super-twisting sliding-mode controller (STSMC). However, the control performance may be destroyed due to parameter uncertainties, friction and backlash nonlinearities of the ball-screw and external disturbances. Therefore, to improve the robustness and to achieve high precision-positioning, an OASTSMC is designed to achieve this purpose. The OASTSMC incorporates a STSMC, a FLNN identifier and an optimal feedback controller. The STSMC is adopted to reduce the chattering, the FLNN identifier is developed for the approximation of uncertain nonlinear dynamics online and the infinite horizon optimal control is developed using a critic NN and ADP to facilitate the online solution of the Hamilton-Jacobi-Bellman (HJB) equation. The dynamic behavior of linear-stage using the OASTSMC assures the stability of the closed-loop and guarantees the optimal performance for the overall system. The validation of the proposed control scheme is carried out to verify the efficacy of the OASTSMC approach through experimental analysis. The experimental results confirm good dynamic performance of linear-stage.

This paper proposes a robust adaptive supertwisting sliding-mode control (RASTSMC) scheme for PMSM-driven linear stage control system with uncertain nonlinear dynamics to achieve high precision-positioning. First, a supertwisting sliding-mode controller (STSMC) is designed to stabilize the linear stage. However, the control performance may be destroyed due to the unknown model uncertainties, friction and backlash nonlinearities of the ball-screw, the parameter variations of the PMSM servo drive and external disturbances. Therefore, to improve the robustness of the control system performance, a RASTSMC is proposed, which incorporates a STSMC, a function-link interval type-2 Petri fuzzy-neural-network (FLIT2PFNN) estimator and a robust controller. The STSMC is adopted to reduce the chattering phenomenon, the FLIT2PFNN estimator is developed for the approximation of the unknown nonlinear dynamics online and the robust controller is designed to recover the residual of the FLIT2PFNN approximation errors. Furthermore, the online adaptive laws are derived based on the Lyapunov approach, so that the stability and robustness of the overall control system are guaranteed. A real-time implementation is carried out via dSPACE1104 control to verify the efficacy of the proposed control approach. Furthermore, the experimental results of the proposed RASTSMC shows good dynamic performance regardless of unknown model uncertainties and external disturbances.

Switched reluctance motors (SRMs) are used in the industry due to their simple motor design construction, the susceptibility of running at wide speed range, high torque to inertia ratio, low cost, and high reliability. In this paper, the SRM drive system is fed from asymmetric four-phase power converter (APC) using soft switching technique. This paper presents a proposed precise speed controller (PSC) for a four-phase 75 KW 8/6 SRM. The performance of the PSC is evaluated and compared with PI and fuzzy logic (FLC) speed controllers. This comparison is based on the values of the rise time, settling time, overshoot, undershoot, speed error in the steady state, and torque ripples percentage of the three speed controllers. The robustness of the proposed PSC is validated in such cases e.g. mechanical parameter disparities, and external load disturbances. The four-phase SRM responses of motor speed versus speed command, speed error, four-phase currents, SRM reference current, and electromagnetic torque are investigated using MATLAB/SIMULINK. Keywords: Switched reluctance motor (SRM), Precise speed controller (PSC), Asymmetric power converter (APC), Fuzzy logic controller (FLC)

In wind energy conversion systems (WECS), the turbine captures part of the wind energy and converses it to mechanical energy through a dynamic interaction with the electrical generator which in turn converts this mechanical energy to electrical energy. Therefore, the dynamics of the wind turbine is very important in research and development of the overall WECS. Having a real wind turbine or a site with convenient wind conditions is not always a guaranteed option for conducting research. Hence, it is very desirable to create wind turbine dynamics through wind turbine emulation. In this paper, a wind turbine emulation system using a permanent magnet synchronous motor (PMSM) is designed, simulated, implemented, and tested experimentally. The PMSM is torque-controlled using field orientation technique. A three-phase IGBT inverter with closed loop current PI-controllers is used to drive the PMSM. A dSPACE DS1104 DSP prototyping platform is used to handle the real-time execution of the control programs. The system is tested and the torque-speed characteristics of the emulated wind turbine are verified experimentally at different feeds of wind speeds and generator loads. Keywords: Wind energy conversion system, Wind turbine emulator, PMSM control

PurposeThis paper aims to explore to what extent can the Saudi–US alliance endure, given the several challenges it has faced over the past decade. Using a conceptual framework from the alliance theory, the paper will trace the historical evolution of the alliance between the two countries, then will identify some of the challenges that have faced the alliance on both the regional and bilateral levels, and finally will assess the impact of these challenges on the resilience of the Saudi–US alliance.Design/methodology/approachThis paper will use the alliance theory literature to analyze the challenges and the resilience of the Saudi–US relations.FindingsThe Saudi–US alliance has encountered several challenges in the past decade such as the Arab spring, the Iranian nuclear deal and the Civil War in Syria and Yemen. However, this alliance proved to be resilient, and the strategic partnership between the two countries managed to overcome these challenges.Originality/valueThe importance of this paper stems from the fact that the USA and the Saudi Arabia are two pivotal countries, and their relationship affects regional and international dynamics. The paper contributes to the literature on the Saudi–US bilateral relations as well as their views on recent regional issues such as the Arab Spring, the civil war in Yemen and Syria. Assessing the limits and potentials of the alliance between the two countries could also help us understand the future of regional developments in the Middle East.

This paper introduces a simple and accurate seamless transfer control strategy for PV Distributed Generator (DG). This seamless transfer guarantees the stable operation of the critical loads fed by the DG during transition from grid connection to the standalone mode or vice versa. This strategy is based on classical PI controller which operates in two modes of operation. The first mode is the standalone mode where the PI controller acts as a voltage regulator. The second mode is the grid connected mode where the PI operates as a current controller. The PV operates in two modes of operation as well. The first mode is the MPPT mode during which a Perturb and Observe (P&O) technique is responsible for maximum power extraction from the PV arrays. This mode is active during grid connection. The second mode is active during standalone operation where a PI controller is responsible for stabilizing the DC-link voltage by manipulating the boost converters duty ratio. The simulation results show the effectiveness of the proposed control strategy.

This paper presents an improved dynamics proportional-integral (IDPI) speed control for four-phase 8/6 switched reluctance motor (SRM). The SRM is used in the industrial applications owing to its simple structure, low cost, fault-tolerance, and high torque to inertia ratio. In this paper, the 75 kW, four-phase 8/6 SRM is supplied from asymmetric power converter (APC) with soft switching method. The parameters of the proposed IDPI speed control are calculated from the mechanical mathematical model and the pre-defined drive system response. By obtaining the IDPI parameters, different speed response can be accomplished at various operating conditions. Moreover, the SRM currents are controlled by hysteresis current control (HCC). The proposed IDPI is assessed and compared with the neural network and the conventional PI controllers. The comparison between the three controllers comprises the rise time, settling time, overshoot, undershoot, speed error, and the torque ripples percentage. The proposed IDPI robustness is investigated during load disturbance and 100% increase in the motor inertia conditions.

Sliding Discrete Fourier Transform (SDFT) is very efficient regarding computational load and it possesses a very fast phase angle detection with excellent harmonic rejection at nominal frequency. However, at off-nominal frequency, SDFT generates errors in both magnitude and phase angle due to spectral leakage. This paper introduces a workaround for Fourier Transform to handle this disability under off-nominal frequency while avoiding variable-rate sampling. Sliding Fourier Transform (SFT) is used as a phase detector for a phase-locked loop whose output frequency is used to drive the SFT. The paper revisits the mathematics of Fourier Transform (FT) in a three-phase setting via a time-domain approach to show a newly proposed filtering technique for the double-frequency oscillation just by summing the FT sine/cosine filter outputs of the three individual phases. Also, the analysis aims to determine and correct the phase and magnitude errors under offnominal frequency operation. The proposed technique (SFT-PLL) is tested in real time on dSPACE DS1202 DSP using voltage vectors that are pregenerated to simulate the most adverse grid conditions. The testing scenarios compare the performance of the SFT-PLL with that of the Decoupled Stationary Reference Frame PLL (dαβPLL). The results prove that SFT-PLL is superior to dαβPLL.

AIM To investigate how Tregs are regulated in chronic hepatitis C virus (HCV) patients via assessment of Tregs markers (granzyme 2, CD69 and FoxP3), Teffs markers [TNFRSF4 (OX40), INFG] and CD4, CD25 genes. METHODS A prospective study was conducted on 120 subjects divided into 4 groups: Group I (n = 30) treatment naïve chronic HCV patients; Group II (n = 30) chronic HCV treated with Peg/Riba; Group III (n = 30) chronic HCV associated with non-organ specific autoantibody and Group IV (n = 30) healthy persons as a control group. Tregs and Teffs markers were assessed in peripheral blood mononuclear cells by quantitative real time reverse transcriptase-polymerase chain reaction. RESULTS Chronic HCV patients exhibited significant higher levels of both Teffs and Tregs in comparison to healthy control group. Tregs markers were significantly decreased in Peg/Riba treated HCV patients in comparison to treatment naïve HCV group. In HCV patients with antinuclear antibody (ANA) +ve, Tregs markers were significantly decreased in comparison to all other studied groups. Teffs markers were significantly elevated in all HCV groups in comparison to control and in HCV group with ANA +ve in comparison to treatment naïve HCV group. CONCLUSION Elevated Tregs cells in chronic HCV patients dampen both CD4+ and CD8+ autologous T cell immune response. Interferon-α and ribavirin therapy suppress proliferation of Tregs. More significant suppression of Tregs was observed in HCV patients with autoantibodies favoring pathological autoimmune response.

This paper presents an evaluation and investigation of a dynamic adaptive observer for the surface permanent magnet synchronous motor (PMSM) drive performance under the speed sensorless intelligent control. Sensorless speed control of PMSM as a more robust, smaller size and less expensive solution is presented. A Luenberger statebased adaptive (LSA) observer is proposed here to estimate the rotor position and angular speed of the motor. These estimated values are the feedback for vector control in the current loop and for speed control in the speed loop. The rotor angular speed is regulated by using speed fuzzy logic controller (FLC). This paper presents a contribution in eliminating the need for three voltage sensors which measure the three-phase voltages. These voltage sensors increase the system cost and reduce the system reliability. However, these costs can be eliminated by proper calculation. The system mathematical modeling and the experimental verifications of the proposed LSA observer and the speed FLC for the PMSM are introduced. A 850 w PMSM drive test setup is designed and constructed including a dSPACE 1104 as the control heart of the proposed system. The simulation and experimental results are demonstrated to verify the validity of the proposed LSA dynamic observer for sensorless fuzzy-based speed controller of PMSMs.

This paper presents a complete design of model reference adaptive control (MRAC) for a Wind Turbine-Driven doubly-fed induction generator (DFIG) based on vector-oriented control. First, the system modeling is presented including the modeling of the grid side converter (GSC) and the DFIG; second, a design of MRAC for the current control loops of both GSC and the rotor side converter (RSC) is presented; finally, the outer control loops, the speed and the DC-link voltage loops, are designed using PI controller. Several tests have been done to evaluate the performance of using MRAC in this system. First of all, the complete system is simulated using Matlab/Simulink and the system is tested under different conditions to show the performance of the designed MRAC. Finally, an experimental test on the grid side converter is implemented to verify the simulation results of using MRAC.

Background Atopic dermatitis (AD) is one of the most frequent chronic inflammatory skin diseases that is often associated with a personal or a family history of asthma, allergic rhinitis, or conjunctivitis. One hallmark of AD is the striking susceptibility to colonization with Staphylococcus aureus. Toll-like receptors (TLRs) are a major class of pattern recognition receptors that are involved in detecting invading pathogens in the skin and initiating a cutaneous immune response. TLRs participate in cutaneous host defense mechanisms against various skin infections caused by common bacterial, fungal, and viral pathogens. Objectives The aims of this study are to examine the relation between the severity of the clinical features of AD and the expression of TLR2 and to evaluate the expression of TLR2 on peripheral blood monocytes of AD patients, and correlate it with serum IgE. Participants and methods Thirty patients with AD were included in this study (14 males and 16 females between 6 months and 26 years of age). All patients with AD fulfilled the diagnostic criteria of Hanifin and Rajka. They were examined clinically and the severity of eczema was assessed using the Nottingham Eczema Severity Score. Twenty-five healthy matched volunteers (15 males and 10 females) served as controls. Routine laboratory examinations were recorded, total serum IgE was determined using a chemiluminescent liquid-phase immunoassay, and TLR2 number on peripheral blood monocytes was determined by flow cytometry. Results There was no statistically significant difference in the level of expression of TLR2 on peripheral blood monocytes of patients with AD in either the intrinsic or the extrinsic groups compared with those of the controls. However, there was a highly statistically significant positive correlation between the TLR2 level and a personal history of other allergic diseases. Serum total IgE levels were elevated in 73.9% of patients with AD. Moreover, a highly significant positive correlation was found between serum IgE and the surface area score for AD. Conclusion TLR2 expression is related to a personal history of multiple allergic diseases rather than to AD alone. The serum IgE level is related to the surface area score for AD.

Direct torque control (DTC) is known to produce the fastest torque response in AC drives. In this paper, a wind turbine emulation (WTE) system using a squirrel cage induction motor (SCIM) working in a DTC mode is designed, implemented, and tested experimentally using Hardware-in-loop (HIL). The flux estimation is based on the current model where two stator currents and the rotor speed are measured. The DTC is realised using a space vector modulator to avoid variable switching frequency associated with the DTC switching tables. dSPACE MicroLabBox is used to handle the real-time control programmed in SIMULINK. Typhoon HIL402 is used to emulate the inverter, the machine, the connected mechanical load, and the feedback sensors of the current dc link voltage and speed. Thanks to the great flexibility offered by the HIL technique, a variety of tests has been conducted to validate the overall system performance. The tests include step change of load, step change of wind speed, operation under stochastic wind spe...

AIM: To assess co-stimulatory and co-inhibitory markers of dendritic cells (DCs) in hepatitis C virus (HCV) infected subjects with and without uremia. METHODS: Three subject groups were included in the study: group 1 involved 50 control subjects, group 2 involved 50 patients with chronic HCV infection and group 3 involved 50 HCV uremic subjects undergoing hemodialysis. CD83, CD86 and CD40 as co-stimulatory markers and PD-L1 as a co-inhibitory marker were assessed in peripheral blood mononuclear cells by real-time polymerase chain reaction. Interleukin-10 (IL-10) and hyaluronic acid (HA) levels were also assessed. All findings were correlated with disease activity, viral load and fibrogenesis. RESULTS: There was a significant decrease in co-stimulatory markers; CD83, CD86 and CD40 in groups 2 and 3 vs the control group. Co-stimulatory markers were significantly higher in group 3 vs group 2. There was a significant elevation in PD-L1 in both HCV groups vs the control group. PD-L1 was significantly lower in group 3 vs group 2. There was a significant elevation in IL-10 and HA levels in groups 2 and 3, where IL-10 was higher in group 3 and HA was lower in group 3 vs group 2. HA level was significantly correlated with disease activity and fibrosis grade in group 2. IL-10 was significantly correlated with fibrosis grade in group 2. There were significant negative correlations between co-stimulatory markers and viral load in groups 2 and 3, except CD83 in dialysis patients. There was a significant positive correlation between PD-L1 and viral load in both HCV groups. CONCLUSION: A significant decrease in DC co-stimulatory markers and a significant increase in a DC co-inhibitory marker were observed in HCV subjects and to a lesser extent in dialysis patients.

Atopic dermatitis (AD) is a complex immunologic skin disorder that is expressed when genetically predisposed individuals are exposed to certain environmental stimuli. Inspite of the high prevalence of cytomegalovirus (CMV) infection and its potent immunomodulatory activities, the relation of CMV to AD is still poorly understood and is still to be clarified. The aim of the present study was to evaluate the frequency of active CMV infection in patients with AD and its possible etiologic role in the pathogenesis of the disease. Also, we tried to find if a relation between active CMV infection and disease severity exists. The present study was carried on 31 patients with AD with various degrees of disease severity. Ten apparently healthy subjects were enrolled in the study as a control group. Anti CMV IgG antibodies were estimated by quantitative enzyme immunoassay to discriminate between recent CMV infection and CMV reactivation. Active CMV infection was diagnosed by using nested PCR to detect CMV DNA in the sera of the studied subjects. The detection rate of CMV genome was higher in patients with AD in comparison to the control group. Cytomegalovirus genome was detected in the sera of 52% (16/31) of patients with AD (87.5% of them were seropositive for anti-CMV IgG antibodies). On the other hand no CMV DNA was detected in any of the serum samples of the control subjects. The difference was statistically significant. No significant relation was found between active CMV infection and disease severity. Also, no significant statistical difference was found between the two studied groups as regards the prevalence of latent CMV infection. In addition, no significant difference was detected between anti-CMV IgG antibody levels in all seropositive subjects. Our results denote that active subclinical CMV infection is more frequent in patients with AD and may have possible immunomodulatory role in the etiopathogenesis of AD but it is not related to disease severity.

Chronic renal failure (CRF) is a common disease with high morbidity and mortality. The inadequacy of current treatment modalities and insufficiency of donor organs for cadaveric transplantation have driven a search for improved methods of dealing with renal failure. This raises the concept of cell-based therapy using mesenchymal stem cells (MSCs). The purpose of this work is to evaluate the effect of MSCs in rats with CRF and to detect the level of B-cell lymphoma 2 (Bcl-2) and basic fibroblast growth factor (bFGF) as possible antiapoptotic and anti-inflammatory paracrine mediators of MSCs action. This study was carried on female albino rats, which were divided into 3 groups, control group, CRF group and CRF/MSCs group. MSCs were derived from bone marrow of male albino rats and were characterized morphologically and by RT-PCR for CD29. Serum urea, creatinine, Na, K, systolic blood pressure and 24-hour urinary albumin were estimated for all groups, Y-chromosome gene (Sry) was detected by PCR in renal tissue. Also Bcl-2 and bFGF were examined by RT-PCR in renal tissue of all studied groups and the kidney was examined pathologically. The results of this work showed that CRF rats receiving MSCs showed significantly lowered serum urea, creatinine and urinary albumin levels compared to the CRF group. Also improvement of serum Na and K was observed in CRF/MSCs group compared to CRF group. As regard Bcl-2 and bFGF they were highly expressed in renal tissue of CRF/MSCs group compared to the CRF group. The (Sry) gene was detected by PCR in the renal tissue of CRF/MSCs group. These results demonstrate a potential of MSCs to ameliorate the kidney function in rats with CRF possibly through the antiapoptotic and anti-inflammatory paracrine mediators of MSCs.