3D Laser-and-tissue Agnostic Data-driven Method for Robotic Laser Surgical Planning

In robotic laser surgery, shape prediction of an one-shot ablation cavity is an important problem for minimizing errant overcutting of healthy tissue during the course of pathological tissue resection and precise tumor removal. Since it is difficult to physically model the laser-tissue interaction due to the variety of optical tissue properties, complicated process of heat transfer, and uncertainty about the chemical reaction, we propose a 3D cavity prediction model based on an entirely data-driven method without any assumptions of laser settings and tissue properties. Based on the cavity prediction model, we formulate a novel robotic laser planning problem to determine the optimal laser incident configuration, which aims to create a cavity that aligns with the surface target (e.g. tumor, pathological tissue). To solve the one-shot ablation cavity prediction problem, we model the 3D geometric relation between the tissue surface and the laser energy profile as a non-linear regression problem that can be represented by a single-layer perceptron (SLP) network. The SLP network is encoded in a novel kinematic model to predict the shape of the post-ablation cavity with an arbitrary laser input. To estimate the SLP network parameters, we formulate a dataset of one-shot laser-phantom cavities reconstructed by the optical coherence tomography (OCT) B-scan images for the data-driven modelling. To verify the method. The learned cavity prediction model is applied to solve a simplified robotic laser planning problem modelled as a surface alignment error minimization problem. The initial results report (91.1 +- 3.0)% 3D-cavity-Intersection-over-Union (3D-cavity-IoU) for the 3D cavity prediction and an average of 97.9% success rate for the simulated surface alignment experiments

Atomic Sn–enabled high-utilization, large-capacity, and long-life Na anode

Constructing robust nucleation sites with an ultrafine size in a confined environment is essential toward simultaneously achieving superior utilization, high capacity, and long-term durability in Na metal-based energy storage, yet remains largely unexplored. Here, we report a previously unexplored design of spatially confined atomic Sn in hollow carbon spheres for homogeneous nucleation and dendrite-free growth. The designed architecture maximizes Sn utilization, prevents agglomeration, mitigates volume variation, and allows complete alloying-dealloying with high-affinity Sn as persistent nucleation sites, contrary to conventional spatially exposed large-size ones without dealloying. Thus, conformal deposition is achieved, rendering an exceptional capacity of 16 mAh cm−2 in half-cells and long cycling over 7000 hours in symmetric cells. Moreover, the well-known paradox is surmounted, delivering record-high Na utilization (e.g., 85%) and large capacity (e.g., 8 mAh cm−2) while maintaining extraordinary durability over 5000 hours, representing an important breakthrough for stabilizing Na anode

Carbon quantum dots improve the mechanical behavior of polyvinyl alcohol/polyethylene glycol hydrogel

As the wear and tear effects of artificial joints disturb patients after joint replacement, techniques of new lubrication materials or methods are constantly being investigated. Hydrothermal method was adopted to produce carbon quantum dots (CDs), and physically cross-linked polyvinyl alcohol-polyethylene glycol hydrogel (PVA-PEG) to encapsulate CDs, which was evaluated as a lubricant for lubrication appraisal with their slow-release solution. Results of the friction experiment showed that the addition of CDs changed the structure of the gel and promoted the tribological properties of the gel. The structural characterization results show that the CDs are successfully wrapped in gel. The network cross-linked structure of the gel is improved due to the addition of CDs, which are shown by the results of thermogravimetric analysis (TGA) and differential scanning calorimetry analysis (DSC). At the same time, CDs can influence the thermal stability and crystallinity of the gel as well as the degree of cross-linking. These results of TGA and DSC suggest that the curled molecular chain will not be stretched during the gel cross-linking process. After 2 h of self-healing, the recovered gel did not break again under the pull of external force. All these contribute to the preparation and application of hydrogels which is worth looking forward to accelerate the development of polymer lubrication

Immunomodulatory nano-preparations for rheumatoid arthritis

AbstractRheumatoid arthritis (RA) is a systemic autoimmune disease (AD) caused by the aberrant attack of the immune system on its own joint tissues. Genetic and environmental factors are the main reasons of immune system impairment and high incidence of RA. Although there are medications on the market that lessen disease activity, there is no known cure for RA, and patients are at risk in varying degrees of systemic immunosuppression. By transporting (encapsulating or surface binding) RA-related self-antigens, nucleic acids, immunomodulators, or cytokines, tolerogenic nanoparticles—also known as immunomodulatory nano-preparations—have the potential to gently regulate local immune responses and ultimately induce antigen-specific immune tolerance. We review the recent advances in immunomodulatory nano-preparations for delivering self-antigen or self-antigen plus immunomodulator, simulating apoptotic cell avatars in vivo, acting as artificial antigen-presenting cells, and based on scaffolds and gels, to provide a reference for developing new immunotherapies for RA

A directed self-assembly quasi-spider silk protein expressed in Pichia pastoris

The spider silk protein has distinctive physical, chemical, mechanical and biological properties. As a functional material, the application value of spider silk has increased in many fields. Consequently, considerable progress has been made in the expression of recombinant spider silk proteins through many host systems by gene engineering techniques. However, the mechanical properties of the silk fibre spun with the recombinant spider silk proteins are unsatisfactory because the recombinant spider silk proteins have too low of a molecular weight and do not have molecular orientation. This paper describes the construction and expression of a quasi-spider silk protein composed of spider silk protein and collagen-like peptides with the Pichia pastoris expression system. The quasi-spider silk protein is an ‘ABA-type’ triblock copolymer composed of triple helix-forming A blocks at both ends of the middle section. The triple helix-forming A blocks at both ends of the triblock copolymers consist of (Pro–Gly–Pro)n homopolymeric stretches, and the middle section of the molecule (B section) contains a spider silk protein that has been optimally designed. The supramolecular structure created by the three-block copolymers through directed self-assembly ensures that the artificial spider silk fibres will meet the requirement for molecular weight and definite molecular orientation, thus promoting the formation of silk fibres. The authors hope that this project will contribute to the study of materials science and biomedical engineering in regards to the huge potential of spider silk protein in these fields

Glassy Metal–Organic-Framework-Based Quasi-Solid-State Electrolyte for High-Performance Lithium-Metal Batteries

Enhancing ionic conductivity of quasi-solid-state electrolytes (QSSEs) is one of the top priorities, while conventional metal–organic frameworks (MOFs) severely impede ion migration due to their abundant grain boundaries. Herein, ZIF-4 glass, a subset of MOFs, is reported as QSSEs (LGZ) for lithium-metal batteries. With lean Li content (0.12 wt%) and solvent amount (19.4 wt%), LGZ can achieve a remarkable ion conductivity of 1.61 × 10−4 S cm−1 at 30 °C, higher than those of crystalline ZIF-4-based QSSEs (LCZ, 8.21 × 10−5 S cm−1) and the reported QSSEs containing high Li contents (0.32–5.4 wt%) and huge plasticizer (30–70 wt%). Even at −56.6 °C, LGZ can still deliver a conductivity of 5.96 × 10−6 S cm−1 (vs 4.51 × 10−7 S cm−1 for LCZ). Owing to the grain boundary-free and isotropic properties of glassy ZIF-4, the facilitated ion conduction enables a homogeneous ion flux, suppressing Li dendrites. When paired with LiFePO4 cathode, LGZ cell demonstrates a prominent cycling capacity of 101 mAh g−1 for 500 cycles at 1 C with the near-utility retention, outperforming LCZ (30.7 mAh g−1) and the explored MOF-/covalent–organic frameworks (COF)-based QSSEs. Hence, MOF glasses will be a potential platform for practical quasi-solid-state batteries in the future. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH Gmb