Adaptive compliant skill learning for contact-rich manipulation with human in the loop

It is essential for the robot manipulator to adapt to unexpected events and dynamic environments while executing the physical contact-rich tasks. Although a range of methods have been investigated to enhance the adaptability and generalization capability of robot manipulation, it is still difficult to perform complex contact-rich tasks, e.g., rolling pizza dough and robot-assisted medical scanning, without the assistance from a human in the loop. We proposed a novel framework combining learning from demonstration (LfD) and human experience to enhance the safety and adaptability of the robot manipulation. In this framework, dynamic movement primitives (DMPs) is employed for manipulation skills learning from demonstrations, and human correction is applied to update the pre-trained DMPs skills model. We conducted experiments on the Franka Emika Panda Robot with pizza dough rolling tasks. The results demonstrate that the proposed framework could effectively improve the performance of the physical contact-rich tasks, and the human correction method through teleoperation provides a potential solution for advanced interaction tasks with complex and dynamic physical properties

From teleoperation to autonomous robot-assisted microsurgery: A survey

Robot-assisted microsurgery (RAMS) has many benefits compared to traditional microsurgery. Microsurgical platforms with advanced control strategies, high-quality micro-imaging modalities and micro-sensing systems are worth developing to further enhance the clinical outcomes of RAMS. Within only a few decades, microsurgical robotics has evolved into a rapidly developing research field with increasing attention all over the world. Despite the appreciated benefits, significant challenges remain to be solved. In this review paper, the emerging concepts and achievements of RAMS will be presented. We introduce the development tendency of RAMS from teleoperation to autonomous systems. We highlight the upcoming new research opportunities that require joint efforts from both clinicians and engineers to pursue further outcomes for RAMS in years to come

The tumor suppressive role of CAMK2N1 in castration-resistant prostate cancer.

Prostate cancer at advanced stages including metastatic and castration-resistant cancer remains incurable due to the lack of effective therapies. The CAMK2N1 gene, cloned and characterized as an inhibitor of CaMKII (calcium/calmodulin-dependent protein kinase II), has been shown to affect tumorigenesis and tumor growth. However, it is still unknown whether CAMK2N1 plays a role in prostate cancer development. We first examined the protein and mRNA levels of CAMK2N1 and observed a significant decrease in human prostate cancers comparing to normal prostate tissues. Re-expression of CAMK2N1 in prostate cancer cells reduced cellular proliferation, arrested cells in G0/G1 phases, and induced apoptotic cell death accompanied by down-regulation of IGF-1, ErbB2, and VEGF downstream kinases PI3K/AKT, as well as the MEK/ERK-mediated signaling pathways. Conversely, knockdown of CAMK2N1 had a significant opposite effects on these phenotypes. Our analyses suggest that CAMK2N1 plays a tumor suppressive role in prostate cancer cells. Reduced CAMK2N1 expression correlates to human prostate cancer progression and predicts poor clinical outcome, indicating that CAMK2N1 may serve as a biomarker. The inhibition of tumor growth by expressing CAMK2N1 established a role of CAMK2N1 as a therapeutic target

CAMK2N1 inhibits prostate cancer progression through androgen receptor-dependent signaling.

Castration resistance is a major obstacle to hormonal therapy for prostate cancer patients. Although androgen independence of prostate cancer growth is a known contributing factor to endocrine resistance, the mechanism of androgen receptor deregulation in endocrine resistance is still poorly understood. Herein, the CAMK2N1 was shown to contribute to the human prostate cancer cell growth and survival through AR-dependent signaling. Reduced expression of CAMK2N1 was correlated to recurrence-free survival of prostate cancer patients with high levels of AR expression in their tumor. CAMK2N1 and AR signaling form an auto-regulatory negative feedback loop: CAMK2N1 expression was down-regulated by AR activation; while CAMK2N1 inhibited AR expression and transactivation through CAMKII and AKT pathways. Knockdown of CAMK2N1 in prostate cancer cells alleviated Casodex inhibition of cell growth, while re-expression of CAMK2N1 in castration-resistant cells sensitized the cells to Casodex treatment. Taken together, our findings suggest that CAMK2N1 plays a tumor suppressive role and serves as a crucial determinant of the resistance of prostate cancer to endocrine therapies

Layer-by-layer self-assembled weak polyelectrolyte-based novel multilayered film : fabrication, unique properties and applications

Layer-by-layer (LbL) self-assembled weak polyelectrolyte-based multilayered films have shown superior tunability and versatility to other polyelectrolyte multilayers. Previous works have focused primarily on the assembly of linearly grown synthetic weak polyelectrolyte multilayers. Further investigation is warranted of weak polyelectrolyte-based self-assembly systems such as natural weak polyelectrolyte multilayers, nanoparticle-participated weak polyelectrolyte multilayers, and exponentially grown multilayers, their unique properties, and novel applications. In particular, in this PhD research project, a chitosan/alginate multilayer film was constructed via LbL self-assembly. The surface composition of the self-assembled multilayer film can be tailored through pH adjustment during the assembly process. The loading capacity of the antibody on the multilayered film and the binding activity of the antigen to the immobilized antibody can be well-tuned by pH control. This work can provide more scientific insight into the interaction between protein and polymer matrix and render a novel, simple approach to build high-performance biointerfaces through pH control for potential applications of highly sensitive immunosensors.DOCTOR OF PHILOSOPHY (SCBE

In-situ Self-Assembly of Graphene Supported MnO2 Nanowires for Enhanced Water Oxidation in Both Alkaline and Neutral Solutions

The sluggish water oxidation reaction represents a significant challenge in water splitting for energy storage using hydrogen. We herein reported a graphene supported MnO2 nanowires with an ultrasmall diameter and ultrahigh aspect ratio using a novel in-situ self-assembly approach. This nanostructure was investigated as water oxidation catalysts, showing an ultrahigh catalytic activity and good durability in both alkaline and neutral conditions

Charged drug delivery by ultrafast exponentially grown weak polyelectrolyte multilayers: amphoteric properties, ultrahigh loading capacity and pH-responsiveness

Exponentially growing layer-by-layer hierarchical nanoporous films have been used as a promising system for controlled drug loading/release applications. However, its growth mechanism and factors affecting the drug loading/release are still unclear. In this study, high molecular weight branched poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAA) were utilized as model weak polyelectrolytes to investigate the growth mechanism and the drug loading/release of the multilayers. The pH-dependent growth behavior, interdiffusion of PEI and morphological changes of the film indicate that a pH-dependent polyelectrolyte interdiffusion mechanism is involved in the ultrafast exponential growth process. It is discovered, for the first time, that the fabricated films possess a pH-triggered switchable polarity and tunable charge density associated to the outermost layer, which can enable the loading of anionic or cationic drugs while offering a broad range of pH-controlled release rates and ultralong release times. The multi-layered film has also achieved the highest pH-controlled drug loading/release capacity. This study not only provides a superior platform for the controlled delivery of charged drugs, but also proposes an exponential growth mechanism for weak polyelectrolyte multilayered films

Controlled self-assembly of Ni foam supported poly(ethyleneimine)/reduced graphene oxide three-dimensional composite electrodes with remarkable synergistic effects for efficient oxygen evolution

Three-dimensional (3-D) composite oxygen evolution electrodes with synergistic effects are promising to significantly boost the efficiency of the oxygen evolution reaction (OER). However, their fabrication presents great challenges. Herein, for the first time we show that layer-by-layer (LbL) self-assembly on 3-D substrates can be employed to controllably fabricate 3-D composite electrodes. Ni foam (NF) supported poly(ethyleneimine) (PEI)/reduced graphene oxide (RGO) multilayers fabricated via this approach have tunable catalytic properties. The optimum one achieves the current density of 10 mA cm−2 at an overpotential of 322 mV, which is lower than those of most reported transition metal-based OER catalysts and non-metal ones as well as those of state-of-the-art Ir/C, Ru/C, IrO2/C, and RuO2 measured under the same conditions (0.1 M KOH). It shows a Tafel slope of 78 mV dec−1, which is among the lowest reported for transition metal-based OER catalysts and non-metal ones and comparable to or even lower than that of state-of-the-art Ir and Ru-based ones measured in 0.1 M KOH. In addition, this electrode exhibits a potential increase from 0.55 V to 0.58 V vs. SCE after 18.8 h of chronopotentiometry testing at 10 mA cm−2 and retains 85.8% of the current density at 1.0 V vs. SCE after 350 CV cycles, revealing its good stability. The high catalytic performance could be attributed to in situ formed Ni(OH)2 with RGO-promoted activity, high-density C[double bond, length as m-dash]O rich edge-exposed RGO nanosheets, and the covalently crosslinked multilayer structure of chemically stable RGO nanosheets. All of these properties arise from synergistic interactions between NF, PEI, and RGO. This work offers a facile, mild, controllable, and economical strategy to synergistically assemble conventional poor OER catalysts for low-cost, highly active, and durable 3-D OER electrodes. It also provides scientific insight into the mechanism for the superior and tunable OER catalytic activity, which is critical for further improving the OER catalytic performance

Template-mediated growth of microsphere, microbelt and nanorod α-MoO3 structures and their high pseudo-capacitances

Controlling the morphology and size of α-MoO3 is crucial to obtain superior electrochemical properties for electrochemical energy storage and conversion devices. Herein, one, two and three-dimensional α-MoO3 have been controllably synthesized on a large scale with templates via a facile hydrothermal method, and the growth mechanism was investigated and discussed. These three α-MoO3 exhibit excellent pseudo-capacitive energy storage capability and long cycle life. The α-MoO3 nanorod not only has the best pseudocapacitance among as-prepared α-MoO3, but also demonstrates much higher capacitance than those of reported α-MoO3 nanostructures by 2–4 times. Our findings provide an effective solution for the controlled synthesis of different structures of α-MoO3, which can pave the way to further improve the energy storage and energy conversion efficiency of MoO3-based devices. This facile route could be potentially applied to rationally design other high performance oriented oxides

In situ synthesized heteropoly acid/polyaniline/graphene nanocomposites to simultaneously boost both double layer- and pseudo-capacitance for supercapacitors

It is challenging to simultaneously increase double layer- and pseudo-capacitance for supercapacitors. Phosphomolybdic acid/polyaniline/graphene nanocomposites (PMo12–PANI/GS) were prepared by using PMo12 as a bifunctional reagent for not only well dispersing graphene for high electrochemical double layer capacitance but also in situ chemically polymerizing aniline for high pseudocapacitance, resulting in a specific capacitance of 587 F g−1, which is ∼1.5 and 6 times higher than that of PANI/GS (392 F g−1) and GS (103 F g−1), respectively. The nanocomposites also exhibit good reversibility and stability. Other kinds of heteropolyacids such as molybdovanadophosphoric acids (PMo12−xVx, x = 1, 2 and 3) were also used to prepare PMo12−xVx–PANI/GS nanocomposites, also showing enhanced double layer- and pseudo-capacitance. This further proves the proposed concept to simultaneously boost both double layer- and pseudo-capacitance and demonstrates that it could be a universal approach to significantly improve the capacitance for supercapacitors