A Mini-Review: Fabrication of Polysaccharide Composite Materials Based on Self-Assembled Chitin Nanofibers.

This mini-review presents the fabrication methods for polysaccharide composite materials that employ self-assembled chitin nanofibers (ChNFs) as functional components. Chitin is one of the most abundant polysaccharides in nature. However, it is mostly not utilized because of its poor feasibility and processability. Self-assembled ChNFs are efficiently obtained by a regenerative bottom-up process from chitin ion gels using an ionic liquid, 1-allyl-3-methylimodazolium bromide. This is accomplished by immersing the gels in methanol. The resulting dispersion is subjected to filtration to isolate the regenerated materials, producing ChNF films with a morphology defined by highly entangled nanofibers. The bundles are disintegrated by electrostatic repulsion among the amino groups on the ChNFs in aqueous acetic acid to produce thinner fibers known as scaled-down ChNFs. The self-assembled and scaled-down ChNFs are combined with other chitin components to fabricate chitin-based composite materials. ChNF-based composite materials are fabricated through combination with other polysaccharides.

Cooperative planning for physically interacting heterogeneous robots.

Heterogeneous multi-agent systems can be deployed to complete a variety of tasks, including some that are impossible using a single generic modality. This paper introduces an approach to solving the problem of cooperative behavior planning in small heterogeneous robot teams where members can both function independently as well as physically interact with each other in ways that give rise to additional functionality. This approach enables, for the first time, the cooperative completion of tasks that are infeasible when using any single modality from those agents comprising the team.

Enhancing the dielectric and thermal properties of polytetrafluoroethylene-based composites through designing and constructing a novel interfacial structure.

Polytetrafluoroethylene (PTFE) is widely used as a fundamental core material for high-frequency and high-speed signal transmission fields due to its excellent dielectric properties. However, the high coefficient of thermal expansion (CTE) characteristic of PTFE severely limits its practical application. The CTE of PTFE can be reduced by filling with SiO2, which is always accompanied by a rapid deterioration of dielectric properties due to the poor interfacial compatibility between SiO2 and PTFE matrix. In this paper, the challenge of synergistic regulation of dielectric and CTE properties for PTFE-based composites is overcome by constructing an interfacial structure with physical interactions. Micro-mesoporous SiO2 (mSiO2) is prepared and introduced as a filler, compared with smooth surface SiO2 (sSiO2), the presence of micro-mesoporous in mSiO2 allows PTFE molecular chains to be adsorbed on the surface or in the pore channels of mSiO2, which improves the interfacial combination of the mSiO2/PTFE composites through the physical interaction between mSiO2 and PTFE. The results show that mSiO2/PTFE composite exhibits a lower CTE (58 ppm °C-1) while maintaining a lower dielectric constant (εr, 2.29, 30 GHz) with dielectric loss (tan Î´, 2.31 × 10-3, 30 GHz) at a filler addition of 30 vol%, as compared with that of the sSiO2/PTFE composites. This work provides a new strategy for fabricating PTFE-based composites with low CTE as well as low εr and tan Î´.

A comparative study to investigate the individual contribution of metabolic and physical interaction on volatiles formation in the mixed fermentation of Torulaspora delbrueckii and Saccharomyces cerevisiae.

It is well-known that the co-inoculation of Saccharomyces cerevisiae and non-Saccharomyces strains can modulate and improve the aromatic quality of wine through their multi-level interactions. However, the individual contribution of metabolic interaction (MI) and physical interaction (PI) on wine volatiles remains poorly understood. In this work, we utilized a double-compartment bioreactor to examine the aromatic effect of MI and PI by comparing the volatiles production in Torulaspora delbrueckii and Saccharomyces cerevisiae single fermentations to their mixed fermentations with or without physical separation. Results showed that the PI between T. delbrueckii and S. cerevisiae increased the production of most aroma compounds, especially for acetate esters and volatile fatty acids. In comparison, the MI only promoted a few volatile compounds, including ethyl decanoate, isoamyl acetate, and isobutanol. Noticeably, the MI significantly decreased the levels of ethyl dodecanoate, 2-phenylethyl alcohol, and decanoic acid, which exhibited opposite profiles in PI. Our results indicated that the PI was mainly responsible for the improved volatiles in T. delbrueckii/S. cerevisiae mixed fermentation, while the MI can be targeted to modulate the specific aroma compounds. A thorough understanding of the PI and MI aromatic effect will empower winemakers to accurately and directionally control the volatile profile of the wine, promoting the application of multi-starters to produce diverse styles of wines.

Induction of Fungal Secondary Metabolites by Co-Culture with Actinomycete Producing HDAC Inhibitor Trichostatins.

A recently bioinformatic analysis of genomic sequences of fungi indicated that fungi are able to produce more secondary metabolites than expected. Despite their potency, many biosynthetic pathways are silent in the absence of specific culture conditions or chemical cues. To access cryptic metabolism, 108 fungal strains isolated from various sites were cultured with or without Streptomyces sp. 13F051 which mainly produces trichostatin analogues, followed by comparison of metabolic profiles using LC-MS. Among the 108 fungal strains, 14 produced secondary metabolites that were not recognized or were scarcely produced in mono-cultivation. Of these two fungal strains, Myrmecridium schulzeri 15F098 and Scleroconidioma sphagnicola 15S058 produced four new compounds (1-4) along with a known compound (5), demonstrating that all four compounds were produced by physical interaction with Streptomyces sp. 13F051. Bioactivity evaluation indicated that compounds 3-5 impede migration of MDA-MB-231 breast cancer cells.

Master-Slave Control System for Virtual-Physical Interactions Using Hands.

Among the existing technologies for hand protection, master-slave control technology has been extensively researched and applied within the field of safety engineering to mitigate the occurrence of safety incidents. However, it has been identified through research that traditional master-slave control technologies no longer meet current production and lifestyle needs, and they have even begun to pose new safety risks. To resolve the safety risks exposed by traditional master-slave control, this research fuses master-slave control technology for hands with virtual reality technology, and the design of a master-slave control system for hands based on virtual reality technology is investigated. This study aims to realize the design of a master-slave control system for virtual-physical interactions using hands that captures the position, orientation, and finger joint angles of the user's hand in real time and synchronizes the motion of the slave interactive device with that of a virtual hand. With amplitude limiting, jitter elimination, and a complementary filtering algorithm, the original motion data collected by the designed glove are turned into a Kalman-filtering-algorithm-based driving database, which drives the synchronous interaction of the virtual hand and a mechanical hand. As for the experimental results, the output data for the roll, pitch, and yaw were in the stable ranges of -0.1° to 0.1°, -0.15° to 0.15°, and -0.15° to 0.15°, respectively, which met the accuracy requirements for the system's operation under different conditions. More importantly, these data prove that, in terms of accuracy and denoising, the data-processing algorithm was relatively compatible with the hardware platform of the system. Based on the algorithm for the virtual-physical interaction model, the authors introduced the concept of an auxiliary hand into the research, put forward an algorithmic process and a judgement condition for the stable grasp of the virtual hand's, and solved a model-penetrating problem while enhancing the immersive experience during virtual-physical interactions. In an interactive experiment, a dynamic accuracy test was run on the system. As shown by the experimental data and the interactive effect, the system was satisfactorily stable and interactive.

Communications between macrophages and cardiomyocytes.

The heart is a muscular organ that pumps blood throughout the body and is one of the most vital organs in human body. While cardiomyocytes are essential for maintaining the normal function of the heart, a variety of cardiovascular diseases such as coronary artery occlusion, arrhythmia, and myocarditis can lead to cardiomyocyte death, resulting in deterioration of heart function. The adult mammalian heart is incapable of regenerating sufficient cardiomyocytes following cardiac injuries, eventually leading to heart failure and death. Cardiac macrophages are ubiquitously distributed in the healthy heart and accumulated at the site of injury. Macrophages play essential roles in regulating homeostasis and proliferation of cardiomyocyte, promoting electrical conduction, and removing dead cardiomyocytes and debris through direct and indirect cell-cell crosstalk. In this review, we summarize the latest insights into the role of macrophages in maintaining cardiac homeostasis and the macrophage-cardiomyocyte crosstalk in both healthy and injured scenarios. Video Abstract.

Evaluating steroid hormone receptor interactions using the live-cell NanoBRET proximity assay.

Steroid hormone receptors play a crucial role in the development and characterization of the majority of breast cancers. These receptors canonically function through homodimerization, but physical interactions between different hormone receptors play a key role in cell functions as well. The estrogen receptor (ERα) and progesterone receptor (PR), for example, are involved in a complex set of interactions known as ERα/PR crosstalk. Here, we developed a valuable panel of nuclear receptor expression plasmids specifically for use in NanoBRET assays to assess nuclear receptor homo- and heterodimerization. We demonstrate the utility of this assay system by assessing ERα/PR physical interaction in the context of the endocrine therapy resistance-associated ERα Y537S mutation. We identify a role of the ERα Y537S mutation beyond that of constitutive activity of the receptor; it also increases ERα/PR crosstalk. In total, the NanoBRET assay provides a novel avenue for investigating hormone receptor crosstalk. Future research may use this system to assess the effects of other clinically significant hormone receptor mutations on hormone receptor crosstalk.

LEVELNET to visualize, explore, and compare protein-protein interaction networks.

Physical interactions between proteins are central to all biological processes. Yet, the current knowledge of who interacts with whom in the cell and in what manner relies on partial, noisy, and highly heterogeneous data. Thus, there is a need for methods comprehensively describing and organizing such data. LEVELNET is a versatile and interactive tool for visualizing, exploring, and comparing protein-protein interaction (PPI) networks inferred from different types of evidence. LEVELNET helps to break down the complexity of PPI networks by representing them as multi-layered graphs and by facilitating the direct comparison of their subnetworks toward biological interpretation. It focuses primarily on the protein chains whose 3D structures are available in the Protein Data Bank. We showcase some potential applications, such as investigating the structural evidence supporting PPIs associated to specific biological processes, assessing the co-localization of interaction partners, comparing the PPI networks obtained through computational experiments versus homology transfer, and creating PPI benchmarks with desired properties.

Polymer Nanoantidotes.

Intoxication is one of the most common causes of accidental death globally. Although some antidotes capable of neutralizing the toxicity of certain xenobiotics have become well established, the current reality is that clinicians primarily rely on nonspecific extracorporeal techniques to remove toxins. Nano-intervention strategies in which nanoantidotes neutralize toxicity in situ via physical interaction, chemical bonding, or biomimetic clearance have begun to show clinical potential. However, most nanoantidotes remain in the proof-of-concept stage, and the difficulty of constructing clinical relevance models and the unclear pharmacokinetics of nanoantidotes hinder their translation to clinic. This Concept reviews the detoxification mechanisms of polymer nanoantidotes and predicts the opportunities and challenges associated with their clinical application.

Nonlinear Model Predictive Impedance Control of a Fully Actuated Hexarotor for Physical Interaction.

In this paper, the problem of a fully actuated hexarotor performing a physical interaction with the environment through a rigidly attached tool is considered. A nonlinear model predictive impedance control (NMPIC) method is proposed to achieve the goal in which the controller is able to simultaneously handle the constraints and maintain the compliant behavior. The design of NMPIC is the combination of a nonlinear model predictive control and impedance control based on the dynamics of the system. A disturbance observer is exploited to estimate the external wrench and then provide compensation for the model which was employed in the controller. Moreover, a weight adaptive strategy is proposed to perform the online tuning of the weighting matrix of the cost function within the optimal problem of NMPIC to improve the performance and stability. The effectiveness and advantages of the proposed method are validated by several simulations in different scenarios compared with the general impedance controller. The results also indicate that the proposed method opens a novel way for interaction force regulation.

Research progress of microparticles in traditional Chinese medicine decoction / 药学学报

Decoction is a classical dosage form of traditional Chinese medicines. In the process of decocting, various complex components produce physical interactions and chemical reactions, among which physical interactions include van der Waals force, hydrogen bond, electrostatic interaction, π-π stacking, etc., and chemical reactions include Maillard reaction, oxidation reaction, hydrolysis reaction, degradation reaction, polymerization reaction, etc. New substances and original ingredients from chemical reactions can be further activated. These effects form the basis of particle formation in the broth. The sizes of the particles in decoctions range from nanoscale to micron scale, mostly composed of polysaccharide, protein matrix, wrapped in water insoluble molecules, can increase the dispersion of insoluble components and the stability of unstable components, as well as reduce the volatile components and toxic components of volatile components, and ultimately achieve the purpose of efficient absorption and toxicity reduction. From the angle of physical change and chemical reaction in the process of decoction, this paper expounds the formation mechanism of particles in decoction, expounds the research method of particles, analyzes the components in particles and the interaction between components, and then explains the pharmacodynamic characteristics of traditional Chinese medicine decoction, which provides the foundation for the modernization of Chinese decoction.

Human-Robot Joint Misalignment, Physical Interaction, and Gait Kinematic Assessment in Ankle-Foot Orthoses.

Lower limb exoskeletons and orthoses have been increasingly used to assist the user during gait rehabilitation through torque transmission and motor stability. However, the physical human-robot interface (HRi) has not been properly addressed. Current orthoses lead to spurious forces at the HRi that cause adverse effects and high abandonment rates. This study aims to assess and compare, in a holistic approach, human-robot joint misalignment and gait kinematics in three fixation designs of ankle-foot orthoses (AFOs). These are AFOs with a frontal shin guard (F-AFO), lateral shin guard (L-AFO), and the ankle modulus of the H2 exoskeleton (H2-AFO). An experimental protocol was implemented to assess misalignment, fixation displacement, pressure interactions, user-perceived comfort, and gait kinematics during walking with the three AFOs. The F-AFO showed reduced vertical misalignment (peak of 1.37 ± 0.90 cm, p-value < 0.05), interactions (median pressures of 0.39-3.12 kPa), and higher user-perceived comfort (p-value < 0.05) when compared to H2-AFO (peak misalignment of 2.95 ± 0.64 and pressures ranging from 3.19 to 19.78 kPa). F-AFO also improves the L-AFO in pressure (median pressures ranging from 8.64 to 10.83 kPa) and comfort (p-value < 0.05). All AFOs significantly modified hip joint angle regarding control gait (p-value < 0.01), while the H2-AFO also affected knee joint angle (p-value < 0.01) and gait spatiotemporal parameters (p-value < 0.05). Overall, findings indicate that an AFO with a frontal shin guard and a sports shoe is effective at reducing misalignment and pressure at the HRI, increasing comfort with slight changes in gait kinematics.

HRpI System Based on Wavenet Controller with Human Cooperative-in-the-Loop for Neurorehabilitation Purposes.

There exist several methods aimed at human-robot physical interaction (HRpI) to provide physical therapy in patients. The use of haptics has become an option to display forces along a given path so as to it guides the physiotherapist protocol. Critical in this regard is the motion control for haptic guidance to convey the specifications of the clinical protocol. Given the inherent patient variability, a conclusive demand of these HRpI methods is the need to modify online its response with neither rejecting nor neglecting interaction forces but to process them as patient interaction. In this paper, considering the nonlinear dynamics of the robot interacting bilaterally with a patient, we propose a novel adaptive control to guarantee stable haptic guidance by processing the causality of patient interaction forces, despite unknown robot dynamics and uncertainties. The controller implements radial basis neural network with daughter RASP1 wavelets activation function to identify the coupled interaction dynamics. For an efficient online implementation, an output infinite impulse response filter prunes negligible signals and nodes to deal with overparametrization. This contributes to adapt online the feedback gains of a globally stable discrete PID regulator to yield stiffness control, so the user is guided within a perceptual force field. Effectiveness of the proposed method is verified in real-time bimanual human-in-the-loop experiments.

Traversability analysis with vision and terrain probing for safe legged robot navigation.

Inspired by human behavior when traveling over unknown terrain, this study proposes the use of probing strategies and integrates them into a traversability analysis framework to address safe navigation on unknown rough terrain. Our framework integrates collapsibility information into our existing traversability analysis, as vision and geometric information alone could be misled by unpredictable non-rigid terrains such as soft soil, bush area, or water puddles. With the new traversability analysis framework, our robot has a more comprehensive assessment of unpredictable terrain, which is critical for its safety in outdoor environments. The pipeline first identifies the terrain's geometric and semantic properties using an RGB-D camera and desired probing locations on questionable terrains. These regions are probed using a force sensor to determine the risk of terrain collapsing when the robot steps over it. This risk is formulated as a collapsibility metric, which estimates an unpredictable region's ground collapsibility. Thereafter, the collapsibility metric, together with geometric and semantic spatial data, is combined and analyzed to produce global and local traversability grid maps. These traversability grid maps tell the robot whether it is safe to step over different regions of the map. The grid maps are then utilized to generate optimal paths for the robot to safely navigate to its goal. Our approach has been successfully verified on a quadrupedal robot in both simulation and real-world experiments.

Biological-physical processes regulate autumn prey availability of spiny icefish Chaenodraco wilsoni in the Bransfield Strait, Antarctic.

This study examines the adaptability of a Southern Ocean predator, which is dependent on Antarctic krill (Euphausia superba), to potential changes in food availability. Muscle fatty acids (FAs) of the spiny icefish Chaenodraco wilsoni collected from three areas in the Bransfield Strait (BS), northern Antarctic Peninsula during February-April 2016 give a good representation of their feeding variability. The compositions of 22:6n3 (DHA) and 20:5n3 (EPA) were both higher in the Transitional Zonal Water with Bellingshausen influence (TBW)-controlled C. wilsoni than in the Transitional Zonal Water with Weddell Sea influence (TWW)-controlled fish. This was positively correlated with photoadaptation and carbon sequestration in TBW-controlled phytoplankton. Results for the FAs 16:1n7, 16:0, DHA and EPA indicate the presence of dinoflagellates in all three areas, suggesting that during late summer and early fall, there is a seasonal phytoplankton succession, where small phytoplankton become dominant, in the BS. In addition, the compositions of some long-chain FAs (>20, such as 20:0, 20:1, 22:0 and 22:1n9) and ∑18 indicated that the food chain based on flagellates and copepods was more apparent in TWW-controlled C. wilsoni, especially the effect of El Niño-Southern Oscillation (ENSO) on the variation of prey communities in TWW-controlled areas. FA markers such as SFA/(PUFA+MUFA), ∑15 + ∑17 and ARA were more pronounced in TWW-controlled C. wilsoni, indicating a more strongly carnivorous and benthic food source. In the TBW-TWW confluence, the complex hydrological structure, including the presence of a large number of mesoscale eddies, allows rich nutrients and krill larvae to remain in it, providing a rich food source for the C. wilsoni. Overall, the FA data of this study show that the diet of C. wilsoni varies in different marine environments, aiding their survivability at the face of climate change.

Development of an Integrated Virtual Reality System with Wearable Sensors for Ergonomic Evaluation of Human-Robot Cooperative Workplaces.

This work proposes a novel virtual reality system which makes use of wearable sensors for testing and validation of cooperative workplaces from the ergonomic point of view. The main objective is to show, in real time, the ergonomic evaluation based on a muscular activity analysis within the immersive virtual environment. The system comprises the following key elements: a robotic simulator for modeling the robot and the working environment; virtual reality devices for human immersion and interaction within the simulated environment; five surface electromyographic sensors; and one uniaxial accelerometer for measuring the human ergonomic status. The methodology comprises the following steps: firstly, the virtual environment is constructed with an associated immersive tutorial for the worker; secondly, an ergonomic toolbox is developed for muscular analysis. This analysis involves multiple ergonomic outputs: root mean square for each muscle, a global electromyographic score, and a synthetic index. They are all visualized in the immersive environment during the execution of the task. To test this methodology, experimental trials are conducted on a real use case in a human-robot cooperative workplace typical of the automotive industry. The results showed that the methodology can effectively be applied in the analysis of human-robot interaction, to endow the workers with self-awareness with respect to their physical conditions.

Intermolecular Interactions Drive Protein Adaptive and Coadaptive Evolution at Both Species and Population Levels.

Proteins are the building blocks for almost all the functions in cells. Understanding the molecular evolution of proteins and the forces that shape protein evolution is essential in understanding the basis of function and evolution. Previous studies have shown that adaptation frequently occurs at the protein surface, such as in genes involved in host-pathogen interactions. However, it remains unclear whether adaptive sites are distributed randomly or at regions associated with particular structural or functional characteristics across the genome, since many proteins lack structural or functional annotations. Here, we seek to tackle this question by combining large-scale bioinformatic prediction, structural analysis, phylogenetic inference, and population genomic analysis of Drosophila protein-coding genes. We found that protein sequence adaptation is more relevant to function-related rather than structure-related properties. Interestingly, intermolecular interactions contribute significantly to protein adaptation. We further showed that intermolecular interactions, such as physical interactions, may play a role in the coadaptation of fast-adaptive proteins. We found that strongly differentiated amino acids across geographic regions in protein-coding genes are mostly adaptive, which may contribute to the long-term adaptive evolution. This strongly indicates that a number of adaptive sites tend to be repeatedly mutated and selected throughout evolution in the past, present, and maybe future. Our results highlight the important roles of intermolecular interactions and coadaptation in the adaptive evolution of proteins both at the species and population levels.

Human-Human Hand Interactions Aid Balance During Walking by Haptic Communication.

Principles from human-human physical interaction may be necessary to design more intuitive and seamless robotic devices to aid human movement. Previous studies have shown that light touch can aid balance and that haptic communication can improve performance of physical tasks, but the effects of touch between two humans on walking balance has not been previously characterized. This study examines physical interaction between two persons when one person aids another in performing a beam-walking task. 12 pairs of healthy young adults held a force sensor with one hand while one person walked on a narrow balance beam (2 cm wide x 3.7 m long) and the other person walked overground by their side. We compare balance performance during partnered vs. solo beam-walking to examine the effects of haptic interaction, and we compare hand interaction mechanics during partnered beam-walking vs. overground walking to examine how the interaction aided balance. While holding the hand of a partner, participants were able to walk further on the beam without falling, reduce lateral sway, and decrease angular momentum in the frontal plane. We measured small hand force magnitudes (mean of 2.2 N laterally and 3.4 N vertically) that created opposing torque components about the beam axis and calculated the interaction torque, the overlapping opposing torque that does not contribute to motion of the beam-walker's body. We found higher interaction torque magnitudes during partnered beam-walking vs. partnered overground walking, and correlation between interaction torque magnitude and reductions in lateral sway. To gain insight into feasible controller designs to emulate human-human physical interactions for aiding walking balance, we modeled the relationship between each torque component and motion of the beam-walker's body as a mass-spring-damper system. Our model results show opposite types of mechanical elements (active vs. passive) for the two torque components. Our results demonstrate that hand interactions aid balance during partnered beam-walking by creating opposing torques that primarily serve haptic communication, and our model of the torques suggest control parameters for implementing human-human balance aid in human-robot interactions.