Encapsulation of hydrophobic phthalocyanine with poly(N-isopropylacrylamide)/lipid composite microspheres for thermo-responsive release and photodynamic therapy

Phthalocyanine (Pc) is a type of promising sensitizer molecules for photodynamic therapy (PDT), but its hydrophobicity substantially prevents its applications. In this study, we efficiently encapsulate Pc into poly(N-isopropylacrylamide) (pNIPAM) microgel particles, without or with lipid decoration (i.e., Pc@pNIPAM or Pc@pNIPAM/lipid), to improve its water solubility and prevent aggregation in aqueous medium. The incorporation of lipid molecules significantly enhances the Pc loading efficiency of pNIPAM. These Pc@pNIPAM and Pc@pNIPAM/lipid composite microspheres show thermo-triggered release of Pc and/or lipid due to the phase transition of pNIPAM. Furthermore, in the in vitro experiments, these composite particles work as drug carriers for the hydrophobic Pc to be internalized into HeLa cells. After internalization, the particles show efficient fluorescent imaging and PDT effect. Our work demonstrates promising candidates in promoting the use of hydrophobic drugs including photosensitizers in tumor therapies

Research on Friction Compensation Control for Electric Power Steering System

A novel friction compensation control method is proposed to compensate both the dynamic and static friction torque of steering system. The change of EPS assist torque under fixed amplitude friction compensation torque can cause the diver’s steering feeling fuzzy. That is due to the fact that the friction torque felt by driver varies with EPS assist gain. Therefore, a further modified friction compensation control method is proposed based on EPS assist gain to make the driver have similar friction feeling. Finally, computer simulation and vehicle test are performed to verify the effectiveness of adaptation method in the proposed controller. Test results indicate that the proposed controller improved the driver’s steering performance

Slip Control of Electric Vehicle Based on Tire-Road Friction Coefficient Estimation

The real-time change of tire-road friction coefficient is one of the important factors that influence vehicle safety performance. Besides, the vehicle wheels’ locking up has become an important issue. In order to solve these problems, this paper comes up with a novel slip control of electric vehicle (EV) based on tire-road friction coefficient estimation. First and foremost, a novel method is proposed to estimate the tire-road friction coefficient, and then the reference slip ratio is determined based on the estimation results. Finally, with the reference slip ratio, a slip control based on model predictive control (MPC) is designed to prevent the vehicle wheels from locking up. In this regard, the proposed controller guarantees the optimal braking torque on each wheel by individually controlling the slip ratio of each tire within the stable zone. Theoretical analyses and simulation show that the proposed controller is effective for better braking performance

Theory of frequency response of magnetoelectric effects in radially polarized thin cylindrical composites

A theoretical model for the frequency response of magnetoelectric (ME) effect in thin cylindrical piezoelectric-magnetostrictive composites is presented by using constitutive and elastodynamic equations. The calculated results show that there is a resonant enhancement peak of ME voltage coefficient in the electromechanical resonance region and the ME voltage coefficient at resonance frequency exceeds that at low frequency by one or two orders of magnitude. The resonance frequency is predicted to increase with decreasing average diameter $\bar{D}$ and increasing thickness of magnetostrictive layer tM of the cylindrical composite, which is in good agreement with the experimental results reported in literatures. The corresponding resonance ME voltage coefficient increases with increasing tM , but reaches to a peak value and then decreases with increasing $\bar{D}$. It is indicated that the ME effect of trilayered cylindrical composite is less than that of bilayered one, possibly due to its symmetric structure. Under clamped condition, the resonance frequency will shift to a very high value for both trilayered and bilayered cylindrical composites, while the ME effect has different performance, enhanced in bilayered but suppressed in trilayered cylindrical composite. Our model shows that one can obtain strong ME effect and proper resonance frequency by selecting suitable materials, optimizing its geometry structure and varying mechanical boundary conditions for the cylindrical composite structur

Radar Performance of the OFDM Directional Modulation Waveforms for Joint Radar-Communication

The orthogonal frequency-division multiplexing (OFDM) waveforms have been intensively studied for joint Radar-communication (JRC), which can provide high data rates for wireless communication, and the range-doppler information of the Radar target also can be estimated. In this paper, the OFDM directional modulation (OFDM-DM) waveforms are proposed for the JRC, and its radar performance is investigated by a correlation-based Radar signal processing approach. It has been shown that compared with the OFDM JRC scheme the proposed OFDM-DM waveforms can suppress the interference from the non-target directions, which is validated via the simulation results

Trap modification and mechanoluminescence improvement by Si substitution for Sn in Sr2SnO4:Sm3+ ceramics

A series of Sr1.96Sn1−xSixO4:0.04Sm3+ (x=0, 0.1, 0.15, 0.2, 0.3, 0.4) were synthesized from solid-state reaction. The mechanoluminescence (ML) performance of Sr1.96SnO4:0.04Sm3+ was greatly enhanced by partial Si4+ substitution for Sn4+, and the sample of Sr1.96Sn0.8Si0.2O4:0.04Sm3+ showed weaker afterglow and twice stronger ML intensity than that in Sr1.96 SnO4:0.04Sm3+. The stress response of Sr1.96Sn0.8Si0.2O4:0.04Sm3+ ranged from 250 to 1200 N, and its linearity was greatly restored. Particularly, it was very sensitive in the minimal stress response range. These properties of no load threshold for stress sensing and weak afterglow make Sr1.96Sn0.8Si0.2O4:0.04Sm3+ superior to other excellent ML materials. The introduction of Si4+ caused lattice distortion and promoted defect formation in the system. The trap level energy greatly increased and the trap depth changed, which enhanced the trap ability and therefore improved effectively the ML properties

Visible light induced fast synthesis of protein–polymer conjugates : controllable polymerization and protein activity

Herein visible light is used to induce RAFT polymerization from protein for preparing protein–polymer conjugates at ambient temperature. Polymerization is fast and can be conveniently controlled with irradiation time. By site-specific polymerization of NIPAm to protein, the protein activity is maintained and in certain cases it presents an efficient on–off-switchable property