Abstract While second near-infrared (NIR-II) fluorescence imaging is a promising tool for real-time surveillance of surgical operations, the previously reported organic NIR-II luminescent materials ...for in vivo imaging are predominantly activated by expensive lasers or X-ray with high power and poor illumination homogeneity, which significantly limits their clinical applications. Here we report a white-light activatable NIR-II organic imaging agent by taking advantages of the strong intramolecular/intermolecular D-A interactions of conjugated Y6CT molecules in nanoparticles (Y6CT-NPs), with the brightness of as high as 13315.1, which is over two times that of the brightest laser-activated NIR-II organic contrast agents reported thus far. Upon white-light activation, Y6CT-NPs can achieve not only in vivo imaging of hepatic ischemia reperfusion, but also real-time monitoring of kidney transplantation surgery. During the surgery, identification of the renal vasculature, post-reconstruction assessment of renal allograft vascular integrity, and blood supply analysis of the ureter can be vividly depicted by using Y6CT-NPs with high signal-to-noise ratios upon clinical laparoscopic LED white-light activation. Our work provides efficient molecular design guidelines towards white-light activatable imaging agent and highlights an opportunity for precision imaging theranostics.
The exploitation of ultralong organic room temperature phosphorescence (UORTP) materials lags far behind the need because of the lack of general design strategies. Here we proposed a facile design ...strategy based on the structural control of intramolecular hydrogen bonding (IHB) and push-pull electron effects (PPEEs) to construct highly efficient UORTP materials. Two series of carbazole derivatives with different IHBs and PPEEs were designed accordingly. By enhancing the IHB interactions of the luminophores, the molecular planarity, intermolecular interactions and packing mode were effectively tuned, facilitating the intermolecular electron coupling. PPEEs, enhanced by introducing heteroatoms and heavy atoms, strengthened the intramolecular charge transfer states, which changed the orbital transition configuration of excited states, thus boosting the intersystem crossing (ISC) and spin-orbit coupling (SOC). Consequently, CzPM and CzPMBr with dual IHBs and the strongest PPEEs exhibited ultralong lifetimes (τ
P
) of 1.31 s and 233 ms with the highest phosphorescence quantum yields (
Φ
P
) of 1.7% and 48.6% in their series, respectively. Theoretical investigations revealed that the high-lying intersystem crossing (HISC) between excited singlet states (S
m
,
m
> 1) and triplet states (T
n
,
n
> 1) occurred and played a vital role in enhancing the
Φ
P
values of UORTP materials. Significantly, the SOC matrix elements between S
3
and T
7
(ξ(S
3
,T
7
)) of CzPMBr reached up to 39.95 cm
−1
. Finally, CzPMBr was successfully used as an anti-counterfeiting ink in calligraphy and painting due to its excellent RTP properties. The design strategy based on the structural control of IHBs and PPEEs will greatly widen the design platform of UORTP materials. Meanwhile, the discovery of the HISC process will also provide a new insight for the design of UORTP materials.
A facile design strategy based on the structural control of intramolecular hydrogen bonding and push-pull electron effects was proposed to construct highly efficient UORTP materials.
The problem of distributed adaptive fault tolerant control is investigated for nonlinear multi-agent systems with sensor faults in this paper. By utilizing radial basis function neural networks to ...approximate the unknown continuous nonlinear functions, a distributed-observer-based adaptive neural networks scheme is proposed to estimate each node state, which is unmeasured in the system. Then, a kind of distributed adaptive controller is proposed for each follower based on the sliding mode design technique and fault tolerant control technique. Based on graph and Lyapunov stability theory, it is proved that the tracking errors converge to a small neighborhood of the origin with all signals in the closed-loop system being bounded. Finally, simulation results are given to demonstrate the effectiveness of the control scheme proposed in this paper.
Bioimaging, as a powerful and helpful tool, which allows people to investigate deeply within living organisms, has contributed a lot for both clinical theranostics and scientific research. Pure ...organic room temperature phosphorescence(RTP) materials with the unique features of ultralong luminescence lifetime and large Stokes shift, can efficiently avoid biological autofluorescence and scattered light through a time-resolved imaging modality, and thus are attracting increasing attention. This review classifies pure organic RTP materials into three categories, including small molecule RTP materials, polymer RTP materials and supramolecular RTP materials, and summarizes the recent advances of pure organic RTP materials for bioimaging applications.
This paper considered the fault tolerant tracking control problem of a class of nonlinear systems with actuator fault and system external disturbance. First, by introducing error transformation ...function, the original constrained error is transformed into an equivalent unconstrained signal. Then, based on the performance function and backstepping method, an adaptive actuator fault tolerant control scheme is designed to guarantee that the output tracking error meets the given prescribed requirements. Finally, the simulation results on autonomous underwater vehicle demonstrate the effectiveness of the proposed design technique.
In this article, we investigate the distributed adaptive fault-tolerant formation control problem for a group of heterogeneous multiagent systems consisting of multiple follower unmanned aerial ...vehicles (UAVs) and unmanned ground vehicles (UGVs) with parametric uncertainties and communication link faults. Based on the local states information of the vehicles, the adaptive fault-tolerant formation control protocol with varying control gains is developed for each follower UAV and UGV such that all followers track the dynamic trajectory of the virtual leader and obtain the expected formation configuration simultaneously under the influence of communication link faults and external disturbances. The distributed formation tracking convergence performance is discussed through Lyapunov theory. Finally, a simulation study based on the UAVs–UGVs collaborative systems is provided to show the effectiveness of the developed control strategy.
Fluorescence imaging‐guided photodynamic therapy (PDT) has attracted extensive attention due to its potential of real‐time monitoring the lesion locations and visualizing the treatment process with ...high sensitivity and resolution. Aggregation‐induced emission luminogens (AIEgens) show enhanced fluorescence and reactive oxygen species (ROS) generation after cellular uptake, giving them significant advantages in bioimaging and PDT applications. However, most AIEgens are unfavorable for the application in organisms due to their severe hydrophobicity. Anion‐π+ type AIEgens carry intrinsic charges that can effectively alleviate their hydrophobicity and improve their binding capability to cells, which is expected to enhance the bioimaging quality and PDT performance. This concept summarizes the applications of anion‐π+ type AIEgens in fluorescence imaging, fluorescence imaging‐guided photodynamic anticancer and antimicrobial therapy in recent years, hoping to provide some new ideas for the construction of robust photosensitizers. Finally, the current problems and future challenges of anion‐π+ AIEgens are discussed.
Anion‐π+ AIEgens are drawing increasing attention for their distinct molecular packing in aggregate states. This concept summarizes the recently developed anion‐π+ AIEgens and their applications including fluorescence imaging and fluorescence imaging‐guided photodynamic therapy against pathogenic bacteria and cancers, which will provide some guidelines and further promote the exploitation and clinical application of anion‐π+ AIEgens.
This paper investigates the fault-tolerant formation control problem for heterogeneous multi-agent systems (MASs) consisting of quad-rotor unmanned aerial vehicles (UAVs) and two-wheel driven ...unmanned ground vehicles (UGVs) in the presence of multiple actuator faults. The heterogeneous dynamic characteristics and the uncertainties of the control gain matrix generated by actuator faults, especially the sudden changes to system structure due to finite sequential faults increase the difficulty of the formation control design. The dynamic models of UAVs and UGVs are first transformed to obtain the <inline-formula><tex-math notation="LaTeX">XOY</tex-math></inline-formula> two-dimensional position formation systems of UAVs-UGVs and the <inline-formula><tex-math notation="LaTeX">Z</tex-math></inline-formula>-axis altitude system of UAVs. Then, a distributed adaptive direct fault compensation control strategy is designed for the position system of the UAVs-UGVs and the <inline-formula><tex-math notation="LaTeX">Z</tex-math></inline-formula>-axis altitude subsystems of UAVs, respectively, which can guarantee the expected formation structure under the influence of finite sequential faults. A simulation study based on the UAVs-UGVs cooperative systems is adopted to demonstrate the validity of the proposed fault compensation strategy.
This article proposes a distributed adaptive fault-tolerant formation-containment control with prescribed performance for heterogeneous multiagent systems (MASs) consisting of multiple unmanned ...aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) in the presence of actuator faults. First, utilizing the neighborhood formation error information, the distributed fault-tolerant formation control strategy is developed for the trajectory dynamics of each UAV to achieve the formation tracking, that is, all UAVs track the virtual leader and perform the prespecified formation configuration. Then, the adaptive fault-tolerant containment algorithm, independent of the positions of the leaders, is proposed to guarantee the UGVs converge to the convex hull formed by the leader UAVs. The adaptive estimation scheme is constructed to compensate for the unknown system parameters and actuator loss-of-effectiveness and bias faults. The formation-containment tracking performance is analyzed based on Lyapunov theory with the synchronization errors satisfying the prescribed performance. A simulation example based on UAVs-UGVs systems is adopted to verify the effectiveness of the proposed control strategy.
This paper studies the cooperative fault-tolerant formation control problem of tracking a dynamic leader for heterogeneous multiagent systems consisting of multipile unmanned aerial vehicles (UAVs) ...and unmanned ground vehicles (UGVs) with actuator faults under switching directed interaction topologies. Based on local neighborhood formation information, the distributed fault-tolerant formation controllers are constructed to ensure that all follower UAVs and UGVs can accomplish the demanding formation configuration in the state space and track the dynamic leader’s trajectory. By incorporating the sliding mode control and adaptive control technique, the actuator faults and unknown parameters of follower agents can be compensated. Through the theoretical analysis, it is proved that the cooperatively semiglobally uniformly ultimately boundedness of the closed-loop system is guaranteed, and the formation tracking errors converge to a small adjustable neighborhood of the origin. A simulation example is introduced to show the validity of the proposed distributed fault-tolerant formation control algorithm.
