Cancer cell membrane-camouflaged CuPt nanoalloy boosts chemotherapy of cisplatin prodrug to enhance anticancer effect and reverse cisplatin resistance of tumor.

The biotoxicity and chemotherapeutic resistance of cisplatin (CDDP) pose a challenge for tumor therapy. Practically, the change in the therapeutic response of tumor from resistance to sensitivity are impressive but challenging. To this end, we propose a strategy of "one stone, three birds" by designing a CuPt nanoalloy to simultaneously eliminate GSH, relieve hypoxia, and promote ROS production for effectively reversing the platinum (IV) (Pt(IV), (c,c,t-[Pt(NH3)2Cl2(OOCCH2CH2COOH)2)) resistance. Notably, the CuPt nanoalloy exhibits ternary catalytic capabilities including mimicking GSH oxidase, catalase and peroxidase. With the subsequent disguise of tumor cell membrane, the CuPt nanoalloy is conferred with homologous targeting ability, making it actively recognize tumor cells and then effectively internalized by tumor cells. Upon entering tumor cell, it gives rise to GSH depletion, hypoxia relief, and oxidative stress enhancement by catalyzing the reaction of GSH and H2O2, which mitigates the vicious milieu and ultimately reinforces the tumor response to Pt(IV) treatment. In vivo results prove that combination therapy of mCuPt and Pt(IV) realizes the most significant suppression on A549 cisplatin-resistant tumor. This study provides a potential strategy to design novel nanozyme for conquering resistant tumor.

Highly sensitive and repeatable recording photopolymer for holographic data storage containing N-methylpyrrolidone.

The low photosensitivity of phenanthraquinone-doped poly(methyl methacrylate) (PQ/PMMA) severely limits its recording speed for holographic data storage. A high-performance holographic recording medium based on a unique combination of N-methylpyrrolidone (NMP) regulated PQ/PMMA has been developed. A NMP-PQ/PMMA photopolymer with high sensitivity, high diffraction efficiency and negligible volume shrinkage was successfully fabricated by tuning the composition of the PMMA matrix by varying the ratio of NMP to monomers. The photosensitivity is increased by 6.9 times (from 0.27 cm J-1 to 1.86 cm J-1), the diffraction efficiency is increased from 60% to > 80%, and volume shrinkage is decreased by a factor of 2 (from 0.4% to 0.2%). Further investigation revealed that the addition of NMP significantly reduced the molecular weight of PMMA and increased the amount of MMA residuals, while also improving the solubility of PQ molecules. More interestingly, for the first time, the NMP-PQ/PMMA material could record data information repeatedly at least 6 times. The present study elucidates that the introduction of NMP not only modulates the molecular weight of PMMA but also enables the residual monomer MMA to more easily combine with PQ to form a photoproduct for improved holographic performance.

Tumor Microenvironment-Activated Nanostructure to Enhance MRI Capability and Nanozyme Activity for Highly Tumor-Specific Multimodal Theranostics.

Copper-based nanozymes exhibit excellent antitumor activity but are easily inactivated due to the disturbance of proteins or other macromolecules with sulfhydryl. A tumor microenvironment-responsive CuMnO@Fe3O4 (CMF) core-shell nanozyme for highly efficient tumor theranostics is developed. A platelet-derived growth factor receptor-ß-recognizing cyclic peptide (PDGFB) target is conjugated to the surface of CMF to fabricate a tumor-specific nanozyme (PCMF). The core-shell nanostructure significantly avoids the oxidation and inactivation of copper-based nanozyme, promoting the antitumor activity of PCMF. The weak acid- and GSH-activated T1 and T2 relaxation rate of PCMF contributes to T1 and T2 dual contrast imaging at the tumor site. In addition, the PCMF disintegrates and produces some metal ions that possess Fenton catalytic activity (i.e., Cu+, Mn2+, and Fe2+) under TME. This process significantly depletes GSH, accelerates Fenton and Fenton-like reactions, enhances cellular reactive oxygen species (ROS) levels, and induces cancer cell apoptosis and ferroptosis. PCMF also exhibits photothermal functions, so it can be used in combined photothermal therapy, ferroptosis therapy, and chemodynamic therapy, improving anticancer activity. This work provides insights into the design of an exquisite nanostructure for high-sensitive and tumor-specific theranostics.

Measurement based dimension descent association algorithm for OTHR multi-detection multi-target tracking.

The problem of multi-detection multi-target tracking (MDMTT) using over-the-horizon radar in dense clutter environment is studied in this paper. The biggest challenge of MDMTT is the 3-dimensional multipath data association among measurements, detection models and targets. In particular, a lot of clutter measurements are generated in dense clutter environment, which increase the computational burden of 3-dimensional multipath data association greatly. A measurement based dimension descent association (DDA) algorithm is proposed to solve the 3-dimensional multipath data association, which decomposes the 3-dimensional multipath data association into two 2-dimensional data associations. The proposed algorithm can reduce the computational burden compared with the optimal 3-dimensional multipath data association and the computational complexity is analyzed. Besides, a time extension method is designed to detect the new-born targets that appear in the tracking scene, which is based on the sequential measurements. The convergence of the proposed measurement based DDA algorithm is analyzed. The estimation error can convergence to 0 as the number of Gaussian mixtures tends to infinity. The effectiveness and rapidity of the measurement based DDA algorithm are demonstrated by the comparative simulation with the previously proposed algorithms.

Electrolyte design for Li-ion batteries under extreme operating conditions.

The ideal electrolyte for the widely used LiNi0.8Mn0.1Co0.1O2 (NMC811)||graphite lithium-ion batteries is expected to have the capability of supporting higher voltages (≥4.5 volts), fast charging (≤15 minutes), charging/discharging over a wide temperature range (±60 degrees Celsius) without lithium plating, and non-flammability1-4. No existing electrolyte simultaneously meets all these requirements and electrolyte design is hindered by the absence of an effective guiding principle that addresses the relationships between battery performance, solvation structure and solid-electrolyte-interphase chemistry5. Here we report and validate an electrolyte design strategy based on a group of soft solvents that strikes a balance between weak Li+-solvent interactions, sufficient salt dissociation and desired electrochemistry to fulfil all the aforementioned requirements. Remarkably, the 4.5-volt NMC811||graphite coin cells with areal capacities of more than 2.5 milliampere hours per square centimetre retain 75 per cent (54 per cent) of their room-temperature capacity when these cells are charged and discharged at -50 degrees Celsius (-60 degrees Celsius) at a C rate of 0.1C, and the NMC811||graphite pouch cells with lean electrolyte (2.5 grams per ampere hour) achieve stable cycling with an average Coulombic efficiency of more than 99.9 per cent at -30 degrees Celsius. The comprehensive analysis further reveals an impedance matching between the NMC811 cathode and the graphite anode owing to the formation of similar lithium-fluoride-rich interphases, thus effectively avoiding lithium plating at low temperatures. This electrolyte design principle can be extended to other alkali-metal-ion batteries operating under extreme conditions.

NIR-II Fluorescence Imaging-Guided Oxygen Self-Sufficient Nano-Platform for Precise Enhanced Photodynamic Therapy.

Tumor hypoxia and systemic toxicity seriously affect the efficacy of photodynamic therapy (PDT) and are considered as the "Achilles' heel" of PDT. Herein, to combat such limitations, an intelligent orthogonal emissions LDNP@SiO2 -CaO2 and folic acid-polyethylene glycol-Ce6 nanodrug is rationally designed and fabricated not only for relieving the hypoxic tumor microenvironment (TME) to enhance PDT efficacy, but also for determining the optimal triggering time through second near-infrared (NIR-II) fluorescence imaging. The designed nanodrug continuously releases a large amount of O2 , H2 O2 , and Ca2+ ions when exposed to the acidic TME. Meanwhile, under downshifting NIR-II bioimaging guidance, chlorine e6 (Ce6) consumes oxygen to produce 1 O2 upon excitation of upconversion photon. Moreover, cytotoxic reactive oxygen species (ROS) and calcium overload can induce mitochondria injury and thus enhance the oxidative stress in tumor cells. As a result, the NIR-II bioimaging guided TME-responsive oxygen self-sufficient PDT nanosystem presents enhanced anti-tumor efficacy without obvious systemic toxicity. Thus, the fabricated nanodrug offers great potential for designing an accurate cancer theranostic system.

Phenanthraquinone-Doped Polymethyl Methacrylate Photopolymer for Holographic Recording.

Phenanthraquinone-doped polymethyl methacrylate (PQ/PMMA) photopolymers are considered to be the most promising holographic storage media due to their unique properties, such as high stability, a simple preparation process, low price, and volumetric shrinkage. This paper reviews the development process of PQ/PMMA photopolymers from inception to the present, summarizes the process, and looks at the development potential of PQ/PMMA in practical applications.

Amorphous ferric oxide-coating selenium core-shell nanoparticles: a self-preservation Pt(IV) platform for multi-modal cancer therapies through hydrogen peroxide depletion-mediated anti-angiogenesis, apoptosis and ferroptosis.

A self-preservation Pt(IV) nanoplatform, amorphous ferric oxide-coating selenium core-shell nanoparticles (iAIO@NSe-Pt), was developed for H2O2 depletion-mediated tumor anti-angiogenesis, apoptosis, and ferroptosis. Upon entry into the blood, the ferric oxide shell effectively blocked the contact Pt(IV) prodrug with reduced molecules, then avoided the inactivation of the Pt(IV) prodrug and increased its accumulation in the tumor. After entering cancer cells, iAIO@NSe-Pt caused a series of cascade reactions: (1) AIO on the surface of iAIO@NSe-Pt quickly dissolved, released an abundance of Fe(II) because of the weakly acidic tumor microenvironment, and then catalyzed cellular H2O2 into highly toxic ˙OH, resulting in cellular H2O2 deficiency and cell ferroptosis. (2) The platinum(IV) prodrugs were exposed and quickly reduced to highly toxic Pt(II) by depleting GSH. This process inactivated GPX4, promoted ROS accumulation, and further accelerated ferroptosis. In addition, the generated Pt(II) quickly inhibited DNA replication, achieving effective apoptotic cell death. Meanwhile, Pt(II) inactivated SOD1, which blocked the synthesis of cellular H2O2 and accelerated ROS (superoxide anion radical) accumulation. (3) The deficiency of cellular H2O2 significantly inhibited the expression of vascular endothelial growth factor-A (VEGF-A), blocking tumor angiogenesis and then improving the anticancer effect. (4) After such a cascade reaction, the exposed NSe successively disrupted mitochondrial respiration and inhibited cancer angiogenesis, further inducing cancer cell death. Collectively, our functional and mechanical investigation suggested that iAIO@NSe-Pt exhibits excellent tumor targeting, biocompatibility and anti-tumor efficiency in vitro and in vivo, and provides a novel example of a self-preservation Pt(IV) nanoplatform for H2O2 depletion-mediated tumor anti-angiogenesis, apoptosis, and ferroptosis, showing great promise for future clinical use.

A Biodegradable High-Efficiency Magnetic Nanoliposome Promotes Tumor Microenvironment-Responsive Multimodal Tumor Therapy Along with Switchable T2 Magnetic Resonance Imaging.

We explored the catalytic activity and magnetic resonance imaging (MRI) capacity of Cu-doped ultrasmall iron oxides with different doping ratios. Then, we screened a highly efficient ultrasmall active catalyst (UAC). Subsequently, a biodegradable magnetic nanoliposome was developed for multimodal cancer theranostics through pH-sensitive liposome coating of these UACs. Upon entering the body, the magnetic nanoliposomes significantly prolonged the metabolic time of UACs and promoted their accumulation in tumors. Then, the strong photothermal (PT) effect of the magnetic nanoliposome quickly ablated the tumor, showing promising PT therapy. Upon entering tumor cells, the magnetic nanoliposome rapidly degraded into many UACs and released chemotherapeutic drugs, contributing to chemotherapy. In addition, UACs not only catalyzed Fenton-type reaction to produce excessive reactive oxygen species (ROS) but also inhibited the synthesis of endogenous GSH by inactivating glutamyl cysteine ligase, contributing to cancer ferroptosis. Furthermore, the assembly-dissociation process of UACs showed the function of magnetic relaxation switches, significantly enhancing tumor MRI signal change, achieving a more accurate diagnosis of the tumor. Therefore, this magnetic nanoliposome splits into many UACs upon drug release and regulates the tumor microenvironment to overproduce ROS for enhanced synergistic tumor theranostics, which provides a strategy for developing next-generation magnetic catalysts with biodegradability and multimodal antitumor theranostics.

[International clinical research of critical care medicine in 2021].

The progress of critical care medicine in 2021 is still encouraging. The new international guideline for management of sepsis and septic shock came out after 4 years. Besides, a couple of preferable clinical evidences were released including restrictive blood transfusion strategy for patients with acute myocardial infarction, prevention of peripheral venous catheter infection, heparin inhalation and driving pressure setting in patients with acute respiratory distress syndrome (ARDS), lower oxygenation target for acute hypoxemic respiratory failure, low level positive end-expiratory pressure in non-ARDS patients with respiratory failure, light sedation or non-sedation strategy, biological phenotypes, as well machine learning in sepsis and ARDS. However, we also encounter negative results such as balanced solution during fluid resuscitation, hypothermia therapy after out-of-hospital cardiac arrest or traumatic brain injury, adrenomedullin-specific antibody adrecizumab therapy and coupled plasma filtration-adsorption (CPFA) therapy for patients with septic shock, extracorporeal carbon dioxide removal (ECCO2R) implementation in acute hypoxic respiratory failure, continuous infusion of hypertonic saline in patients with traumatic brain injury. Collectively, in the future, individualized diagnosis and management based on the principle of "wise choice" will become the daily practice scene for all intensivists.

Chinese expert recommendations on management of hepatocellular carcinoma during COVID-19 pandemic: a nationwide multicenter survey.

BACKGROUND: This study aimed to investigate the work status of clinicians in China and their management strategy alteration for patients with hepatocellular carcinoma (HCC) during the COVID-19 pandemic. METHODS: A nationwide online questionnaire survey was conducted in 42 class-A tertiary hospitals across China. Experienced clinicians of HCC-related specialties responded with their work status and management suggestions for HCC patients during the pandemic. RESULTS: 716 doctors responded effectively with a response rate of 60.1%, and 664 were included in the final analysis. Overall, 51.4% (341/664) of clinicians reported more than a 60% reduction of the regular workload and surgeons declared the highest proportion of workload reduction. 92.5% (614/664) of the respondents have been using online medical consultation to substitute for the "face-to-face" visits. Adaptive adjustment for the treatment strategy for HCC was made, including the recommendations of noninvasive and minimally invasive treatments such as transcatheter arterial chemoembolization for early and intermediate stage. Targeted therapy has been the mainstay for advanced stage and also as a bridge therapy for resectable HCC. DISCUSSION: During the COVID-19 pandemic, online medical consultation is recommended to avoid social contact. Targeted therapy as a bridge therapy is recommended for resectable HCC considering the possibility of delayed surgery.

Time-Varying Group Formation-Containment Tracking Control for General Linear Multiagent Systems With Unknown Inputs.

Time-varying group formation-containment tracking problems for general linear multiagent systems with unknown control input are investigated. Agents are classified into tracking leaders, formation leaders, and followers and assigned in groups. Tracking leaders with unknown control inputs provide unpredictable trajectories as macroscopic moving references. Formation leaders accomplish desired subformations while following the trails of tracking leaders. At the same time, followers converge into different convex hulls spanned by formation leaders. First, formation-containment tracking protocols are designed with neighboring relative information and effects of unknown input of tracking leaders. Then, the design of group division is analyzed by adjusting the properties in Laplacian matrices, which represent interaction relationships. An algorithm to determine the parameters in control protocols is proposed, and the formation tracking feasible constraint is presented. Next, it is proved that the general linear multiagent system can achieve time-varying group formation-containment control effectively with errors uniformly asymptotically converging to zero under designed protocols. Finally, a numerical simulation is given to verify the effectiveness of obtained theoretical results.

CuO dot-decorated Cu@Gd2O3 core-shell hierarchical structure for Cu(i) self-supplying chemodynamic therapy in combination with MRI-guided photothermal synergistic therapy.

Theoretically, the Fenton catalytic efficiency of the Cu-based nanoplatform is approximately 160 times that of traditional Fe-based agents. However, the coordination interaction between Cu(ii) and intracellular GSH significantly inhibits the high catalytic activity of Cu(i) generation, dramatically decreasing the Fenton-like catalytic efficiency. Herein, we designed a completely new and highly efficient hierarchical structural nanoplatform to enhance the mimic-peroxidase activity through utilizing comproportionation between CuO and elemental Cu core to self-supply Cu(i). The catalytic rate of this nanoplatform was approximately 55-fold that of traditional Fe-based agents. In a cell assay, this nanoplatform could function as an antagonist of GPX4 and agonist of SOD-1, resulting in intracellular ROS and H2O2 accumulation. Next, the accumulated H2O2 could be quickly catalyzed to highly toxic ˙OH by self-supplying Cu(i), causing strong oxidative stress damage to mitochondria and cell membranes. Under 808 nm laser irradiation, this nanoplatform exhibited a stronger inhibition of tumor growth, and effectively overcame the tumor resistance and recurrence. In addition, this hierarchical structure significantly promoted the interaction between water molecules and gadolinium centers, making TRF-mCuGd possess an ultrahigh T1 MRI contrast performance, and hence, more pathological information of the tumor could be achieved. Overall, this work provides a promising pattern for the design and development of cancer theranostics.

Fully Adaptive Practical Time-Varying Output Formation Tracking for High-Order Nonlinear Stochastic Multiagent System With Multiple Leaders.

Fully adaptive practical time-varying output formation tracking issues of high-order nonlinear stochastic multiagent systems with multiple leaders are researched, where the adaptive fuzzy-logic system (FLS) is introduced for estimating the mismatched integrated uncertain items. Distinctive with former results, stochastic noise is considered in the dynamics, and the followers are required for achieving the time-varying output formation tracking in probability of the convex combination of the leaders' outputs. First, a fully adaptive practical time-varying output formation tracking protocol is put forward, which only utilizes the neighboring relative information, and the global interaction topology information is not used. Besides, the designed protocol employs the adaptive FLSs to estimate the mismatched uncertainties of the followers and the leaders, and the uncertain boundary functions of the stochastic noise. Then, the design process of control protocol and parameter adaptive update law is summarized within four steps in an algorithm. Third, the stability and the properties of the proposed protocol and algorithm are analyzed by employing the Lyapunov theories and stochastic stability theories. Finally, numerical simulation results illustrate the effectiveness of achieved protocol and algorithm.

Distributed finite time cubature information filtering with unknown correlated measurement noises.

This paper addresses the distributed state estimation problem for a class of discrete nonlinear system over sensor networks subject to unknown correlated measurement noises. Firstly, under the condition of network connectivity, a novel communication protocol is developed to ensure every sensor node can gather the information distributed throughout the network within finite communication time. Then a fully distributed estimator is designed by periodically fusing the local information and neighbor's information according to the covariance intersection fusion strategy. Theoretically, it is proved that the distributed estimator in each sensor node is stable with the exponentially bounded estimation error in mean square. Finally, some numerous simulations are performed to illustrate the practical effectiveness and superiority of the proposed state estimator.

ZBTB7A, a potential biomarker for prognosis and immune infiltrates, inhibits progression of endometrial cancer based on bioinformatics analysis and experiments.

BACKGROUD: ZBTB protein is an important member of the C2H2 zinc finger protein family. As a transcription factor, it is widely involved in the transcriptional regulation of genes, cell proliferation, differentiation, and apoptosis. The ZBTB7A has been largely linked to different kinds of tumors due to its diverse function. However, the value for ZBTB7A in uterine corpus endometrial carcinoma (UCEC) is unclear. METHODS: In our work, we assessed the importance of ZBTB7A in UCEC. Firstly, Using Oncomine and Tumor Immunoassay Resource (TIMER) databases to evaluate the expression of ZBTB7A. Secondly, we explored the co-expression network of ZBTB7A through the cBioPortal online tool, Metascape, and LinkedOmics. TIMER was also used to explore the relationship between ZBTB7A and tumor immune invasion, and to detect the correlation between the ZBTB7A and the marker genes related to immune infiltration. Finally, CCK8, migration, ChIP assays were introduced to partly validate ZBTB7A function in endometrial cancer cells. RESULTS: We found the ZBTB7A expression in TIMER was associated with various cancers, especially UCEC. The decreased expression of ZBTB7A was markedly related to the stage and prognosis of UCEC. Furthermore, ZBTB7A was also related to the expression of various immune markers such as Neutrophils, Dendritic cell, T cell (general), Th1, Th2, and Treg. Finally, we verified that ZBTB7A repressed E2F4 transcription and inhibited cells proliferation and migration. These results indicate that ZBTB7A may play a vital role in regulating immune cell infiltration in UCEC, and is a valuable prognostic marker. CONCLUSIONS: In summary, we demonstrate that ZBTB7A is notably downregulated in UCEC, plays a vital role in regulating immune cell infiltration, possesses diagnostic and prognostic values and attenuates E2F4 transcription and cell proliferation, migration in vitro.

Multi-slice spiral CT evaluation of chronic radiation colitis and rectitis.

The aim of the present study was to retrospectively analyse the multi-slice spiral CT (MSCT) findings of radiation colitis and rectitis (RC&R). A total of 23 cases of RC&R detected by helical CT were included. The CT findings and clinical and endoscopy data of the patients were reviewed. The primary tumours included cancers of the cervix (n=17), rectum (n=4), ovaries (n=1) and bladder (n=1). The total dose of radiation per patient was 46-60 Gy (mean, 49.7 Gy) delivered over 5 weeks. The CT manifestations included different degrees of increased thickness of the intestinal wall (n=20, 87.0%), with a maximum thickness of 16.6 mm. On enhanced CT, the target sign was observed (n=16, 69.9%), with an obviously enhanced mucosa and/or serosa and the following changes observed: Oedema and increased density of the mesentery (n=15, 65.2%); increased density of the subcutaneous fat, and blurred and oedematous pelvic wall muscles (n=4, 17.4%), with the obturator internus and levator ani muscles being most commonly affected; narrowed intestinal lumen (n=3, 13.0%); and a small amount of ascitic fluid (n=2, 8.7%) located in the paracolic sulci and bladder or Douglas pouch. The 23 patients underwent colonoscopy and were diagnosed with RC&R. The major manifestations included telangiectasia and mucosal hyperaemia (n=21, 91.3%). MSCT of chronic RC&R (CRC&R) was associated with certain characteristic findings, which, combined with a medical history of radiotherapy and the clinical manifestations, may prove to be of value in the diagnosis of CRC&R.

Oxygen Vacancy Defect-Induced Activity Enhancement of Gd Doping Magnetic Nanocluster for Oxygen Supplying Cancer Theranostics.

This work finds that Fe3O4 nanoclusters can rearrange by Gd doping and then self-assemble to a hollow magnetic nanocluster (HMNC), providing larger magnetic moments to obtain an excellent MRI capability and increasing the number of oxygen vacancies in HMNC. The hollow structure makes platinum(IV) prodrugs effectively load into HMNC. Second, plenty of oxygen vacancy defects can capture oxygen molecules, enhance the catalytic activity of HMNC, and then promote intracellular ROS generation. On the basis of this, a targeting iRGD-labeled HMNC nanosystem (iHMNCPt-O2) is developed through loading oxygen molecules and platinum(IV) prodrugs for chemo- and chemodynamic therapy of cancer. This nanosystem shows an excellent response ability to weak acid and GSH, which can cause a series of cascade reactions in a cell. These cascade reactions are dramatically enhanced at the intracellular ROS level, cause mitochondria and DNA damage, and then induce cancer cell death. Besides, systemic delivery of iHMNCPt-O2 significantly enhanced the MRI contrast signal of tumors and improved the quality of MR images, accurately diagnosing tumors. Therefore, this work provides a novel method for accelerating the Fenton-like reaction and enhancing the MRI capability and fabricates a promising "all-in-one" system to overwhelm the problems of cancer theranostic.

Adaptive fault-tolerant time-varying formation tracking for multi-agent systems under actuator failure and input saturation.

This paper studies the time-varying formation tracking problem for general linear multi-agent systems with multiple leaders in the presence of both actuator failure and input saturation. The followers are required to uniquely determine and track the convex combination of the states of leaders, while maintaining a predefined time-varying formation. A hyperbolic tangent function is firstly introduced to modify the actuator model with input saturation constraint. Then, an augmented plant for dynamics of each follower is constructed to derive the control protocol by exploiting the dynamic surface control technique. The proposed control protocol deals with faults of bias and unknown bounded loss of effectiveness by means of adaptive fault-tolerant strategies, while a formation feasible condition should be satisfied. With the control signal generated by the augmented plant, the time-varying formation error is proved to be semi-globally uniformly bounded under the faults and input saturation, based on standard Lyapunov theory. Finally, a numerical simulation is implemented to demonstrate the effectiveness of the proposed algorithm.

Practical time-varying output formation tracking for high-order nonlinear strict-feedback multi-agent systems with input saturation.

Practical time-varying output formation tracking (PTVOFT) analysis and design task of high-order nonlinear strict-feedback multi-agent systems (MASs) containing control saturation is processed, in which PTVOF error is confined to a narrow range. Distinct with former achievements, agents' model characteristics are high-order nonlinear strict-feedback form with mismatched uncertain nonlinearities and control saturation constraints while multi-follower system is required for achieving PTVOFT for a maneuvering leader. Firstly, hierarchical distributed extended state observer (DESO) is put forward which only employs information between adjacent individuals for approximating mismatched nonlinearities of followers together with mismatched nonlinearities of the leader. Secondly, the practical time-varying output formation tracking protocol can be raised. Backstepping techniques are applied in design procedures to provide primary variables for each control loop, where hierarchical DESOs are utilized for dealing with comprehensive uncertainties. Distributed auxiliary systems are designed for providing compensating signals to achieve the input saturation. Then, the design processes of PTVOFT protocol and hierarchical DESOs are summarized within three steps in an algorithm. Thirdly, the stability and the properties of the proposed protocol and algorithm are analyzed through employing graph theories and Lyapunov theories. Finally, numerical simulation results illustrate the effectiveness of achieved protocol and algorithm.