Light-regulated allosteric switch enables temporal and subcellular control of enzyme activity

Engineered allosteric regulation of protein activity provides significant advantages for the development of robust and broadly applicable tools. However, the application of allosteric switches in optogenetics has been scarce and suffers from critical limitations. Here, we report an optogenetic approach that utilizes an engineered Light-Regulated (LightR) allosteric switch module to achieve tight spatiotemporal control of enzymatic activity. Using the tyrosine kinase Src as a model, we demonstrate efficient regulation of the kinase and identify temporally distinct signaling responses ranging from seconds to minutes. LightR-Src off-kinetics can be tuned by modulating the LightR photoconversion cycle. A fast cycling variant enables the stimulation of transient pulses and local regulation of activity in a selected region of a cell. The design of the LightR module ensures broad applicability of the tool, as we demonstrate by achieving light-mediated regulation of Abl and bRaf kinases as well as Cre recombinase.

A Switch Module Stacked With 4/3 IGBTs With Balanced Voltage Sharing for PEF Applications

Pulsed electric field (PEF) technology is a promising non-thermal pasteurization method that can be utilized to inactivate microorganisms in liquid food with high-voltage PEF. The power switch which is an important component of the PEF systems. This paper presents a design and implementation of an insulated gate bipolar transistor (IGBT) module which includes connections of three series and four parallel IGBTs and its special gate driver for small liquid food treatment systems at home. In this approach, two important issues must be considered. The first is to provide a safe operating condition for each single IGBTs in transient intervals. The second is to design gate drive systems with the capability of driving a large number of discrete devices simultaneously and ensure the current and voltage of single IGBTs in the module to be approximations. To evaluate the operation of the proposed structure, a module of three series and four parallel switches with the voltage capability of 1.8 kV and 60A is tested experimentally.

The Synchronization Transceiver Design and Experimental Verification for the LuTan-1 SAR Satellite

The deviation between the two oscillators in BiSAR systems will cause a residual modulation of echo signal. Therefore, the phase synchronization is an important issue that must be addressed for BiSAR systems. An advanced non-interrupted phase synchronization scheme is used for the LuTan-1 SAR satellite. The synchronization transceiver (STR) is designed for transmitting and receiving synchronization signals. In addition, STR mainly consists of master and auxiliary transceivers and switch module. Furthermore, the function and working principle of STR are introduced, and the detailed design of each part is described. The measured results are also evaluated to prove the performance of the STR. In addition, the phase synchronization accuracy is also demonstrated to verify the effectiveness of the non-interrupted synchronization scheme. The standard deviation (STD) of the residual phase is less than 0.3 degrees. The results have guiding significance for the synchronization unit design of LuTan-1 and the future BiSAR system.