Docking Mechanism Research Articles

Structural design, accuracy analysis, and mechanical calibration of a small two-component docking mechanism for large loads in space

Currently, the passive part of the space station platform’s docking device has been finalized, emphasizing the need for a docking mechanism that enables the on-orbit assembly of large payloads using in-situ resources. This paper presents the design of a compact, high-precision dual-component docking mechanism for large space loads. First, we propose a parametric design for the active and passive sides, accompanied by the constraint equations for the capture mechanism. Next, a progressive positioning method, beginning with coarse correction and followed by fine correction, is proposed. The dual-component calibration and positioning performance are analyzed to initially capture large deviations and achieve high-accuracy docking of electrical and hydraulic connectors subsequently. Static analysis of both single and dual components reveals a positive correlation between load-carrying capacity and diameter. During the prototype testing, the maximum positional deviations were measured 0.12 mm in the X-direction, 0.5 mm in the Y-direction, and 0.07 mm in the Z-direction. The maximum angular deviation was 0.04° when the dual components operated together. Finally, the impact of axial and radial docking conditions in orbit was analyzed to verify that the loading requirements were satisfied. This work offers both theoretical and technical insights for the future development of docking mechanisms for large space loads.

Nonlinear Optimal Control for Spacecraft Rendezvous and Docking Using Symplectic Numerical Method

This paper addresses the autonomous rendezvous and docking between a chaser spacecraft and a target spacecraft. An optimal control method is employed to plan the rendezvous and docking maneuver, considering various constraints, including force, velocity, field of view, and collision avoidance with a diamond-shaped obstacle. The optimal trajectories are derived using a symplectic algorithm, which ensures high accuracy and enhances computational efficiency. These trajectories serve as the reference for the maneuver. A PD-based tracking control method is proposed to enable real-time feedback control. An air-bearing experimental system, encompassing state measurement, data transmission, and processing, is established to conduct ground-based tracking experiments. Furthermore, specialized simulators for the chaser and target spacecraft, equipped with a docking mechanism, are designed. Experimental results validate both the feasibility of the reference trajectories and the effectiveness of the PD tracking control approach.

Targeted Docking of Localized Hydrogen Bond for Efficient and Reversible Zinc-Ion Batteries.

Hydrogen bond (HB) chemistry, a pivotal feature of aqueous zinc-ion batteries, modulates electrochemical processes through weak electrostatic interactions among water molecules. However, significant challenges persist, including sluggish desolvation kinetics and inescapable parasitic reactions at the electrolyte-electrode interface, associated with high water activity and strong Zn2+-solvent coordination. Herein, a targeted localized HB docking mechanism is activated by the polyhydroxy hexitol-based electrolyte, optimizing Zn2+ solvation structures via dipole interaction and reconstructing interfacial HB networks through preferential parallel adsorption. By combining in situ spectroscopic characterizations with theoretical calculations, we elucidate the dynamic evolution of localized HB networks, which enhance Zn2+ deposition kinetics and homogeneity, suppress water-induced side reactions, and mitigate vanadium framework collapse. Our findings support that the targeted HB docking strategy facilitates fast interfacial ion transport kinetics and enables high reversibility, with a substantially prolonged symmetric cell lifespan exceeding 5000 h. This work markedly advances the efficient and reversible zinc-based batteries.

Targeted Docking of Localized Hydrogen Bond for Efficient and Reversible Zinc‐Ion Batteries

Hydrogen bond (HB) chemistry, a pivotal feature of aqueous zinc‐ion batteries, modulates electrochemical processes through weak electrostatic interactions among water molecules. However, significant challenges persist, including sluggish desolvation kinetics and inescapable parasitic reactions at the electrolyte‐electrode interface, associated with high water activity and strong Zn2+‐solvent coordination. Herein, a targeted localized HB docking mechanism is activated by the polyhydroxy hexitol‐based electrolyte, optimizing Zn2+ solvation structures via dipole interaction and reconstructing interfacial HB networks through preferential parallel adsorption. By combining in situ spectroscopic characterizations with theoretical calculations, we elucidate the dynamic evolution of localized HB networks, which enhance Zn2+ deposition kinetics and homogeneity, suppress water‐induced side reactions, and mitigate vanadium framework collapse. Our findings support that the targeted HB docking strategy facilitates fast interfacial ion transport kinetics and enables high reversibility, with a substantially prolonged symmetric cell lifespan exceeding 5000 h. This work markedly advances the efficient and reversible zinc‐based batteries.

A computational chemistry-based approach to optimizing PD-1/PD-L1 inhibitors.

To design effective small molecule inhibitors targeting the immune checkpoint PD-1/PD-L1 and to explore their inhibitory activity. In this paper, a total of 69 PD-1/PD-L1 inhibitors with the same backbone were searched through opendatabases, and their docking mechanism with PD-L1 protein was investigatedby molecular docking method, and the active conformation of the inhibitors was explored. The biological activity of the four newly designed inhibitors was also evaluated using ELISA. The most active molecule 58 in the dataset formed six hydrogen bonds with Phe67, Val55, Ile116 and Tyr123, while the second most active molecule 34 formed five hydrogen bonds with Phe67 and Ala121, both of which formed π-π stacking interactions with Tyr56. The analysis of the inhibitor docking results determined that the residues Tyr123, Gln66, Thr20, Met115, Asp122 and Ile116 had the greatest influence on the active conformation of the inhibitor. ELISA assays suggested that the four novel inhibitors designed had high inhibition rates, with the inhibition rate of compound N2 being as high as 68.53%. In this paper, we have designed and synthesized various PD-1/PDL1 inhibitors, which provide a basis for drug discovery targeting the PD-1/PDL1 signaling pathway.

Mechanism of Ligusticum wallichii-Borneol in the Treatment of Cerebral Ischemic Stroke in Rats Based On Network Pharmacology, Molecular Docking, and Experimental Verification.

The pharmacodynamics, molecular biology, network pharmacology, and molecular docking mechanisms of the Ligusticum wallichii and borneol medication pair (CXBP) were investigated for ischemic stroke treatment. Effective chemical components and targets of CXBP were identified using TCMSP, ETCM, and SymMap databases, whereas ischemic stroke targets were sourced from OMIM, GeneCards, TTD, PubMed, Web of Science, CNKI, Wanfang Data, and VIP databases. Protein-protein interaction (PPI) networks were generated using the STRING database, and GO and KEGG enrichment analyses were conducted using Metascape. A "disease-pathway-target-component-drug" network was created in Cytoscape, and molecular docking was confirmed with PyMOL and AutoDock tools. Rat models of MCAO were established to evaluate neurological scores, triphenyltetrazolium chloride (TTC) staining, and Nissl staining. Key components were validated through enzyme-linked immunosorbent assay (ELISA), real-time polymerase chain reaction (PCR), and immunohistochemistry. Thirty-three active ingredients and 419 potential targets for CXBP, with key compounds including Z-6,8',7,3'-diligustilide, cedrene, (+)-alpha-funebrene, POL, dipterocarpol, oleanolic acid, 1-acetyl-beta-carboline, and erythrodiol. Critical targets included ESR1, PRKCA, and PTPN6. KEGG pathway analysis revealed 179 signaling pathways, primarily neuroactive ligand-receptor interactions, whereas GO enrichment analysis identified 2911 biological processes, 398 molecular activities, and 203 cellular components. The neurological function scores and TTC staining of the infarcted brain regions were significantly improved following CXBP intervention compared to the MCAO group. These findings were supported by Nissl staining, which demonstrated better preserved cellular morphology and a significantly higher number of Nissl vesicles in the CXBP group. ELISA analysis revealed substantial modulation in gene expression: levels of PRKCA, PTPN6, ESR1, and TNF-α changed significantly, whereas IL-1β, IL-6, and TNF-α were notably downregulated compared to the MCAO group. PCR results corroborated these findings, showing a significant decrease in PRKCA expression and marked downregulation of IL-1β, IL-6, and TNF-α, whereas ESR1 and PTPN6 levels increased significantly. Immunohistochemical analysis further confirmed these results, with the CXBP and nimodipine groups exhibiting higher ESR1 and PTPN6 expression and lower PRKCA expression compared to the MCAO group. To improve cerebral ischemia and reperfusion injury, CXBP improves ischemic stroke outcomes through key active ingredients (e.g., Z-6,8',7,3'-diligustilide, cedrene, and oleanolic acid) and targets ESR1, PRKCA, and PTPN6, modulating multiple signaling pathways to alleviate cerebral ischemia-reperfusion injury.

Assessing Physiological Signal Utility and Sensor Burden in Estimating Trust, Situation Awareness, and Mental Workload

Effective human-autonomy teaming is increasingly important to ensuring mission success in operational environments. Modeling operators’ cognitive states, including trust, situation awareness (SA), and mental workload (WL), may improve human-autonomy team performance by informing autonomous systems about human operators. Subjective questionnaires are often used to measure these states but are obtrusive and impractical for real-world operations. Integrating observable and physiological measures could enable unobtrusive measurements of cognitive states. We created models to estimate trust, SA, and WL using observable, physiological, and operator background information (OBI) measures. We collected data from 15 subjects during a spacecraft docking simulation. We developed a LASSO-based algorithm to select features, generated multivariate regression models, and assessed predictive capabilities. Observable and OBI features combined led to the best performing model, indicating that physiological signals do not add significant predictive power. Simultaneous feature selection of SA and WL yielded performance comparable to that of models fit to a single cognitive state, but did not reduce the number of required physiological sensors. The developed algorithm, use of multiple feature modalities, and simultaneously fitting capability can be leveraged for better estimating human cognitive states for human-autonomy teaming.

Understanding Tankyrase Inhibitors and Their Role in the Management of Different Cancer

Abstract: Cancer manifests as uncontrolled cell proliferation. Tankyrase, a poly(ADP-ribose) polymerase member, is vital in Wnt signal transmission, making it a promising cancer therapy target. The Wnt/β-catenin pathway regulates critical biological processes like genomic stability, gene expression, energy utilization, and apoptosis. Its dysregulation contributes to cancer development. Targeting tankyrase within this pathway holds the potential for inhibiting aberrant cell growth and promoting programmed cell death, offering a promising avenue for cancer treatment. ADP-ribosylation, a reversible process, modifies proteins post-synthesis, regulating diverse cellular signaling pathways. Transferase enzymes like mono and poly(ADP- ribosyl) transferases transfer ADP-ribose from NAD+ to specific amino acid side chains or ADP-ribose units on target proteins. Blocking tankyrase has emerged as a promising strategy in cancer treatment. This article reviews recent advancements in developing novel tankyrase inhibitors. It delves into structure-activity relationships, molecular docking, polypharmacology profiles, and binding mechanisms at the active site. Insights into lead structure development aid in designing potent anti-cancer medications, shedding light on promising avenues in cancer therapy.

Invariant Feature Matching in Spacecraft Rendezvous and Docking Optical Imaging Based on Deep Learning

In spacecraft rendezvous and docking, traditional methods that rely on inertial navigation and sensor data face challenges due to sensor inaccuracies, noise, and a lack of multi-approach assurance. Focusing on exploring a new approach as assistance, this study marks the first application of deep learning-based image feature matching in spacecraft docking tasks, introducing the Class-Tuned Invariant Feature Transformer (CtIFT) algorithm. CtIFT incorporates an improved cross-attention mechanism and a custom-designed feature classification module. By using symmetric multi-layer cross-attention, it gradually strengthens inter-feature relationships perception. And, in the feature matcher, it employs feature classification to reduce computational load, thereby achieving high-precision matching. The model is trained on multi-source datasets to enhance its adaptability in complex environments. The method demonstrates outstanding performance across experiments on four spacecraft docking video scenes, with CtIFT being the only feasible solution compared to SIFT and eight state-of-the-art network methods: D2-Net, SuperPoint, SuperGlue, LightGlue, ALIKED, LoFTR, ASpanFormer, and TopicFM+. The number of successfully matched feature points per frame consistently reaches the hundreds, the successful rate remains 100%, and the average processing time is maintained below 0.18 s per frame, an overall performance which far exceeds other methods. The results indicate that this approach achieves strong matching accuracy and robustness in optical docking imaging, supports real-time processing, and provides new technical support for assistance of spacecraft rendezvous and docking tasks.

Space Docking Simulation Simulator Overview

Background: Docking mechanism ground simulation test technology has been a significant issue in the aerospace industry. Docking mechanisms must pass various conventional evaluation tests as a class of electromechanical space products and other space products. Due to the unique nature of the working object environment in space engineering, it is very expensive to simultaneously simulate the docking work under space conditions and conduct ground reproduction tests, so the test technology of the docking mechanism must be thoroughly investigated. Objective: This paper reviews patents on aircraft ground docking and space environment simulation systems to provide insights and references to scholars and researchers in spacecraft simulator manufacturing. Methods: The representative patents associated with each simulation equipment for space docking simulators, including mechanical docking dynamics equipment, space-integrated environment simulation experimental equipment, and thermal vacuum experimental equipment, are described by analyzing the structural functions of these simulators and elaborating on their operating principles and characteristics. Results: By describing various types of space simulators, the current direction of space docking simulators can be optimized, and their future development direction is summarized and analyzed. Conclusion: The comprehensive environmental reproduction of the space docking simulator facilitates the examination of actual problems and potential flaws in spacecraft and has a significant effect on the advancement of the space field.

A Novel Piezoelectric Docking Mechanism Inspired by Bolt-Nut Connector: Design, Modeling, and Experimental Evaluation

A Novel Piezoelectric Docking Mechanism Inspired by Bolt-Nut Connector: Design, Modeling, and Experimental Evaluation

Cpd861 Targeting BCL2 to Alleviate Hepatic Fibrosis: Network Pharmacology, Mendelian Randomization, and Molecular Docking Mechanisms.

Compound 861 (Cpd861) is a traditional Chinese herbal compound for the treatment of hepatic fibrosis (HF). In the current investigation, Cpd861 has been demonstrated to have an underlying molecular mechanism and material foundation for the treatment of HF through network pharmacology, Mendelian randomization (MR), and molecular docking. Public databases were consulted for Cpd861 constituents and HF targets. Protein-protein interactions (PPIs) were established using STRING software, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. To elucidate the causal relationship between potential targets and liver injury, MR was used as a methodological tool. Finally, a molecular docking analysis was conducted between the active compound and the key target. We obtained 174 active ingredients and 113 intersecting genes. Through the PPI network, high-degree targets were identified, namely CTNNB1, ESR1, FOS, MDM2, CCND1, TP53, RELA, and BCL2. As shown by GO and KEGG pathway enrichment analyses, Cpd861 functions through xenobiotic stimulus and oxidative stress-related genes, as well as the PI3K-AKT and non-alcoholic fatty liver disease (NAFLD) signaling pathways. The results of MR showed that MDM2 and BCL2 had a causal relationship with liver injury. Molecular docking results showed that several active compounds in Cpd861 were stably bound to BCL2. This study made predictions regarding the efficacious components, as well as potential targets and pathways of Cpd861 in the therapy of HF. This will open up a new perspective for further investigation of the molecular mechanism of Cpd861 in the treatment of HF.

Comparisons of Energetic Electron Observations Between FIREBIRD‐II CubeSats and POES/MetOp Satellites From 2018 to 2020

AbstractPrecipitation into the atmosphere is one of the main processes by which high energy electrons trapped in Earth's inner magnetosphere are lost from the system. Precipitating electrons can affect the chemical composition of the atmosphere and provide insight into the complex dynamics of the Van Allen radiation belts. This study compares energetic electron precipitation measurements at low‐Earth‐orbit by the Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics (FIREBIRD‐II) CubeSats with NOAA Polar‐orbiting Operational Environmental Satellite (POES) and ESA Meteorological Operational satellite (MetOp) satellites, which are equipped with the Medium‐Energy Proton Electron Detector (MEPED). The analysis considers 51 high quality conjunction events at >300 keV during times of low to moderate geomagnetic activity. The spacecraft capture similar electron flux variability, and FIREBIRD‐II observations fall between POES/MetOp and telescopes, likely a result of FIREBIRD‐II sampling both precipitating and mirrored electrons due to uncertainties in pointing direction. Results demonstrate the value of high‐resolution differential energy observations of electron precipitation by low‐cost CubeSats such as FIREBIRD‐II, especially during periods of low flux.

Multi-Degree-of-Freedom Platforms: Development and Outlook

Background: Multi-degree-of-freedom platforms are frequently employed in space docking devices, motion modeling, and robotics. Complex research is being done on multidegree- of-freedom platforms, including work on spatial route creation, control simulation, and forward and backward platform motion solutions. The development of research platforms in their current state is advantageous for advancing multi-degree-of-freedom motion research, which has the potential to advance numerous sectors through new technology. Objective: In this patent study, the benefits and drawbacks of various platforms are explored to analyze the development trend of platforms for academics and engineers through the most recent development of multi-degree-of-freedom platforms. Methods: By using the research methodology, research substance, and inventive structure of the most recent representative patents of the multi-degree-of-freedom platform, the platform's operating principle and characteristics are demonstrated. Results: By contrasting multi-degree-of-freedom platforms in various application domains, the issues with current multi-degree-of-freedom platforms are enumerated, and the platforms' potential future development path and research topics are suggested. Conclusion: The growth of the aviation, medical, and military industries is aided by the development of multi-degree-of-freedom platforms, and the flexible distribution of high-precision parallel platforms has promising future development.

Investigation of Antimicrobial and Anti-Inflammatory Efficacy of Newly Synthesized Pyrogallol-Coumarin Hybrids: In Vitro and In Silico Studies.

Background: The aim of this study is to present the synthesis of two new compounds with promising antimicrobial and anti-inflammatory properties using precursors that contain pyrogallol and coumarin units. Methods: The characterization of the obtained compounds (PCHs) (E)-N'-(1-(2,4-dioxochroman-3-ylidene)ethyl)-2,3,4-trihydroxybenzohydrazide (PCH-1) and (E)-N'-(1-(2,4-dioxochroman-3-ylidene)ethyl)-3,4,5-trihydroxybenzohydrazide (PCH-2) was performed using various spectroscopic methods in combination with the DFT methods. To evaluate antimicrobial and anti-inflammatory activities, PCHs were tested against 13 different types of microorganisms and soybean lipoxygenase. To determine the specific mechanisms of anti-LOX activity, molecular docking and molecular dynamics studies were performed. Results: These compounds had the most potent antibacterial activity against the bacterium Proteus mirabilis ATCC 12453, with a MIC value of 31.125 µg/mL. In addition, three standard bacterial species were chosen to evaluate the antibiofilm activity of tested substances. The results showed that the strongest effect of PCH-2 was noticed on the biofilm formation of Staphylococcus aureus ATCC 25923 (BIC50 at 378 µg/mL). The anti-LOX results indicate that PCHs have excellent activity with the IC50 value for PCH-1 = 38.12 μM and PCH-2 = 34.12 μM. Conclusions: The obtained in vitro and in silico results confirm the strong inhibitory potential of the investigated compounds.

Exploring statistical physics principles for superior Pefloxacin extraction from water via halloysite nanotubes: Stereographic and topographic evaluation

Exploring statistical physics principles for superior Pefloxacin extraction from water via halloysite nanotubes: Stereographic and topographic evaluation

A non-Lyapunov approach to control design with application to spacecraft docking

A non-Lyapunov approach to control design with application to spacecraft docking

IMMU-57. METHYL-B-CYCLODEXTRIN PARTIALLY REVERSES THE IMMUNOSUPPRESSIVE EFFECTS OF GLIOBLASTOMA DERIVED EXTRACELLULAR VESICLES ON LYMPHOCYTES

Abstract Extracellular vesicles (EVs) derived from glioblastoma (GBM) have been demonstrated in multiple studies to contribute to tumorigenesis, invasion, and immunosuppression. Our prior results demonstrate that EVs can induce the differentiation of myeloid-derived suppressor cells (MDSCs), which in turn impair T cell activation and proliferation in vitro. Methyl-B-Cyclodextrin (MBCD), a cholesterol depleting agent, can interfere with lipid rafts, which are cholesterol rich microdomains on the cellular membrane that act as a docking mechanism for EV uptake. Herein we demonstrate that MBCD can inhibit EV uptake and partially reverse the immunosuppressive effects of EVs on both monocytes and T cells. METHODS EVs were isolated using stepwise ultracentrifugation from GBM cultures. GBM derived EVs were then added to extracted monocytes from donor samples with or without MBCD for 72 hours under hypoxic conditions. The EV exposed monocytes were then co-cultured with T lymphocytes and cell proliferation was measured via flow cytometry. RESULTS Exposure to GBM-derived EVs induced MDSC differentiation in monocytes by at least 50% while the addition of MBCD reduced MDSC levels similar to that of the control group. Moreover, MBCD exposure resulted in increased T cell proliferation in the presence of EV treated monocytes compared to untreated samples. CONCLUSION MBCD can be used as a therapeutic agent to reverse MDSC induction by GBM derived EVs and can partially rescue T cell activation and proliferation.

Baicalin nanofiber membranes: A comprehensive study on preparation, characterization, and antimicrobial pharmacological activities

Baicalin nanofiber membranes: A comprehensive study on preparation, characterization, and antimicrobial pharmacological activities

Design of A Self-Correctable Docking Mechanism in Disturbed Water Surface Environment

The docking mechanism is critical for unmanned surface vehicle (USV) applications, such as traction, dragging, charging, data transmission, building pontoons, etc. These applications are significant for observation, exploration, data acquisition, patrol, rescuing, etc., in aquatic environments. In this paper, a novel autonomous docking mechanism for USVs is proposed. It is capable of (1) docking the USV subject to disturbance efficiently, (2) latching without power consumption after the docking is completed, and (3) guiding the docking head to three specific angles at the end of the docking process. This paper proved the feasibility and rationality of the docking mechanism through theoretical force analysis. Experiments with three different scenarios are implemented to test the mechanism's performance. The experimental results show that the docking success rate is greater than or equal to 90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> on the disturbed water surface.