Search results for "regulator"
showing 10 items of 1009 documents
Regulatory T cells--the renaissance of the suppressor T cells.
2007
Immune reactions are stringently regulated and balanced by complex interactions of stimulating and suppressing mechanisms. Dysfunctions of this sophisticated immune regulatory network can lead to a variety of diseases such as autoimmunity, allergy, cancer, and pregnancy disorders. The rediscovery of suppressor T cells a decade ago--now designated as T regulatory cells--set off a huge avalanche of research activities leading to a multitude of preclinical and clinical studies. Herein, we give a comprehensive review about this research on T regulatory cells and the relevance of this suppressive T cell population for the development of innovative immune therapeutic strategies.
IL-6 controls Th17 immunity in vivo by inhibiting the conversion of conventional T cells into Foxp3+regulatory T cells
2008
The conditions leading to the induction of adaptive Foxp3+regulatory T cells (T-regs) from peripheral T cells in vivo are incompletely understood. Here, we show that unresponsiveness of T cells to IL-6 by T cell-selective deletion of gp130 or immunization of wild-type mice with antigen in incomplete Freund's adjuvant (IFA), which fails to induce IL-6, promotes the conversion of peripheral CD4+T cells into adaptive Foxp3+T-regs. Thus, both T cell-conditional gp130 knockout (KO) mice immunized with MOG35-55 in complete Freund's adjuvant (CFA) and wild-type mice immunized with MOG35-55 in IFA develop overwhelming antigen-specific T-reg responses and are protected from experimental autoimmune e…
Alcohol consumption and hormonal alterations related to muscle hypertrophy: a review
2014
Detrimental effects of acute and chronic alcohol (ethanol) consumption on human physiology are well documented in the literature. These adversely influence neural, metabolic, cardiovascular, and thermoregulatory functions. However, the side effects of ethanol consumption on hormonal fluctuations and subsequent related skeletal muscle alterations have received less attention and as such are not entirely understood. The focus of this review is to identify the side effects of ethanol consumption on the major hormones related to muscle metabolism and clarify how the hormonal profiles are altered by such consumption.
Current-Sensing Technique for Current-Mode Controlled Voltage Regulator Modules
2008
This paper introduces an innovative current-sense technique for voltage regulator modules (VRMs). The proposed method is applied to a multiphase buck converter although the converter topology does not affect the accuracy or effectiveness of the proposed technique. A RC network is parallel connected with the buck converter low-side MOSFET and the voltage signal across the sense capacitor reconstructs the inductor current waveform. The RC technique benefits from all the advantages of the most popular current-sensing technique, the inductor DC resistance current-sense method, cutting off its main disadvantage. The sense network design is oriented to obtain high immunity to noise and a great dy…
The Sequential Switching Shunt Maximum Power Regulator and its Application in the Electric Propulsion System of a Spacecraft
2007
This paper describes a baseline solution of a Power Conditioning and Distribution Unit (PCDU) for Electrical Propulsion (EP) systems. The solution adopted uses two high efficiency, low-mass power regulators; a solar array regulator (SAR) based on the classical Sequential Switching Shunt Regulator with Maximum Power Point Tracking (MPPT) capability followed by a step-up converter to achieve the desired regulated bus voltage. This paper focuses on the first part of the PCDU, the Sequential Switching Shunt Maximum Power Regulator (S3MPR). This electrical architecture has been adapted and recently proposed for the Electric Propulsion power system of the European and Japanese Mercury Mission (Be…
Stationary battery technologies in the U.S.: Development Trends and prospects
2017
Abstract In the last years, stationary battery systems started to attract the attention of stakeholders thanks to their unique ability to decouple power generation and load over time, providing the ancillary services necessary for the stability and the reliability of the electrical system. This is especially true in the presence of high levels of penetration of renewable energy technologies, like wind and solar photovoltaic (PV), because of increased fluctuations in the electricity produced by these renewable sources. Despite the growing interest in energy storage technologies, the academic literature has not completely assessed the development trends of this sector. In order to fill this g…
Modeling the Sequential Switching Shunt Series Regulator
2005
This letter characterizes, in terms of the bandwidth and limit cycle frequency of its constituent subsystems, the sequential switching shunt series regulator -S/sup 4/R, a high-efficiency, low-mass and volume power cell devised to power the next generation of regulated power buses in telecommunication spacecrafts. Transconductance power source modeling is used to obtain linear and nonlinear models. These are used to establish a design control strategy which involves the dynamic response in large load requirements or at the end of the satellite life. Simulations and experimental results are also given to demonstrate the validity of the model.
Non-linear digital control improving transient response: Design and test on a multiphase VRM
2010
Multiphase interleaved buck converters are widely used for point of load applications, especially for VRMs. Performance optimization issue often clashes with size and cost requirements thus leading the industrial and academic research to focus on advanced solutions. This paper presents a control technique for multiphase VRMs including two interacting sections: the linear loop implements a PWM peak current mode control and the nonlinear subsystem modifies few linear loop parameters under load transients only. Steady-state performances are affected by the linear control only while dynamic performance optimization is a non-linear algorithm issue. The proposed control system improves the dynami…
Stationary battery systems in the main world markets: Part 1: Overview of the state-of-the-art
2017
The role of energy storage systems (ESSs) is becoming more and more important in modern power grids, mainly because of the higher penetration of intermittent renewable energy sources (RESs), such as solar and wind power, spurred by advantageous support policies carried out in several countries. The fluctuation nature of the energy produced by RESs is indeed leading to emerging power quality issues or to renewable curtailments. ESSs can be used to balance generation and demand of electricity over time, allowing a higher penetration of RESs into the power network. The energy storage industry is evolving rapidly, and new electrochemical technologies are entering the market. Besides, most elect…
On the Impact of Plant Model and Controller Sophistication on Performance of Disturbance Attenuation and System Robustness
2006
In the paper the problem of disturbance attenuation performance in single-loop control system is investigated. Modified MV control strategy with bounded control variance is used as benchmark for both LQG and classically and optimally tuned PID-type controllers. Certain time and frequency domain functions are then examined to further assess the control performance in terms of robustness. It has been shown that as long as the system to be controlled is delay-free, and there is no extreme demand on performance, simple lag-delay system model along with optimally tuned PID control algorithm provides control quality similar to that of LQG controlled original system assuming the same bound on cont…