•Acetylation conferred ASK polysaccharide better amphiphilic character.•Emulsifying properties of acetylated ASKPs were equal to or better than gum acacia.•Acetylation changed the viscosity of ASKP ...at a wide range.
In the present study, polysaccharides extracted from Artemisia sphaerocephala Krasch. seeds (ASKP) were acetylated to improve the emulsifying properties of the macromolecules. Several methods were applied for the acetylation purpose, among which the acetic anhydride–pyridine method with formamide as solvent was found to be the most effective one. Acetylated ASKPs with various degree of substitution (DS) were successfully produced and structurally characterized using HPSEC-MALS, FTIR and 1H NMR techniques in this study. Results showed that acetylation treatment could cause the degradation of ASKP. Moreover, with the increase of DS, both the molecular weight and radius of gyration increased, as well as the molecular conformation trended to be more compact. Low DS (DS: 0.04 and 0.13) conferred acetylated ASKP a lower viscosity than that of ASKP. With the increase of DS, the viscosity of acetylated ASKPs increased and exceeded that of ASKP. Compared with ASKP, acetylated ASKPs could reduce the surface tension to a greater extent and demonstrated a much smaller droplet size (ZD) in an oil/water emulsion system. Acetylated ASKPs were capable of stabilizing the oil/water emulsion for 3 days at 60°C, whose performance was as good as that of gum acacia. In conclusion, such a hydrophobic modification on ASKP conferred it better emulsifying properties.
The increase of atmospheric CO2 concentration has caused many environmental issues. Electrochemical CO2 reduction reaction (CO2RR) has been considered as a promising strategy to mitigate these ...challenges. The electrocatalysts with a low overpotential, high Faradaic efficiency, and excellent selectivity are of great significance for the CO2RR. Carbon-based materials including metal-free carbon catalysts and metal-based carbon catalysts have shown great potential in the CO2RR, owing to the tailorable porous structures, abundant natural resources, resistance to acids and bases, high-temperature stability, and environmental friendliness. In this review, various carbon materials including graphene, carbon nanotubes, quantum dots, porous carbon, and MOF-derived catalysts, etc., for the CO2RR have been summarized. Particularly, recent progress in terms of the mechanism and pathway of CO2 conversion has been comprehensively reviewed. Finally, the opportunities and challenges of carbon-based electrocatalysts for the CO2RR are proposed.
Carbon-based materials including metal-free carbon catalysts and metal-based carbon catalysts have shown great potential in the electrochemical CO2 reduction reaction, owing to the tailorable porous structures, abundant natural resources, resistance to acids and bases, high-temperature stability, and environmental friendliness. Recent advances in terms of active sites, mechanisms, and pathways of CO2 conversion are comprehensively reviewed. Display omitted
A polymer triple-shape memory effect represents one of the most recent discoveries in the rapidly expanding field of shape memory polymers. It refers to the capability of a polymer to memorize two ...temporary shapes and subsequently recover them, all in one shape memory cycle. Although several examples of triple-shape polymers had been reported in the literature, they were notably evaluated under very different thermo-mechanical conditions. In this study, the effect of various thermo-mechanical conditions on the polymer triple-shape properties was investigated using Nafion as a model material. The choice of the programming and recovery heating methods in constructing triple-shape cycles was found to have a profound impact on the triple-shape properties. As such, the results of this study provided useful reference for future development of triple-shape polymers.
In this paper, a closed-loop control has been developed for the exoskeleton robot system based on brain-machine interface (BMI). Adaptive controllers in joint space, a redundancy resolution method at ...the velocity level, and commands that generated from BMI in task space have been integrated effectively to make the robot perform manipulation tasks controlled by human operator's electroencephalogram. By extracting the features from neural activity, the proposed intention decoding algorithm can generate the commands to control the exoskeleton robot. To achieve optimal motion, a redundancy resolution at the velocity level has been implemented through neural dynamics optimization. Considering human-robot interaction force as well as coupled dynamics during the exoskeleton operation, an adaptive controller with redundancy resolution has been designed to drive the exoskeleton tracking the planned trajectory in human brain and to offer a convenient method of dynamics compensation with minimal knowledge of the dynamics parameters of the exoskeleton robot. Extensive experiments which employed a few subjects have been carried out. In the experiments, subjects successfully fulfilled the given manipulation tasks with convergence of tracking errors, which verified that the proposed brain-controlled exoskeleton robot system is effective.
Most shape memory polymers are rigid and exhibit only one way (irreversible) shape memory effect. This work explored the two-way (reversible) shape memory effect for semi-crystalline elastomeric ...networks. These semi-crystalline networks with various gel fractions and crosslinking densities were synthesized via radical initiated crosslinking of poly(ethylene-co-vinyl acetate). The thermal, mechanical, and the two-way shape memory properties of the resulting materials were investigated. The critical impact of the gel fraction on the two-way shape memory behaviors was revealed. The results from this study establish the basis for potential applications involving soft reversible actuation.
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Nanomedicines can extravasate from tumor vascular lumen into solid tumors via the EPR effect (a) or transcytosis (b). Transcytosis can be further subcategorized as intracellular vesicles-mediated ...(1), vesivulo-vacuolar organelles (VVOs)-mediated (2) or fenestrae-mediated (3) pathways.
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Extravasation is the first step for nanomedicines in circulation to reach targeted solid tumors. Traditional nanomedicines have been designed to extravasate into tumor interstitium through the interendothelial gaps previously assumed rich in tumor blood vessels, i.e., the enhanced permeability and retention (EPR) effect. While the EPR effect has been validated in animal xenograft tumor models, accumulating evidence implies that the EPR effect is very limited and highly heterogeneous in human tumors, leading to highly unpredictable and inefficient extravasation and thus limited therapeutic efficacy of nanomedicines, including those approved in clinics. Enabling EPR-independent extravasation is the key to develop new generation of nanomedicine with enhanced efficacy. Transcytosis of tumor endothelial cells can confer nanomedicines to actively extravasate into solid tumors without relying on the EPR effect. Here, we review and prospectthe development of transcytosis-inducing nanomedicines, in hope of providing instructive insights for design of nanomedicines that can undergo selective transcellular transport across tumor endothelial cells, and thus inspiring the development of next-generation nanomedicines for clinical translation.
Head and neck squamous cell carcinoma (HNSCC) constitute approximately 4% of all cancers worldwide. In this study, we analyzed the expression profile of the long noncoding RNA (lncRNA) of 502 HNSCC ...patients from The Cancer Genome Atlas database. Among the differentially expressed lncRNAs between HNSCC and normal samples, LNCAROD is overexpressed in HNSCC and associated with advanced T stage and shortened overall survival. The N6‐methyladenosine (m6A) modification mediated by METTL3 and METTL14 enhanced the stability of LNCAROD in HNSCC cells. Depletion of LNCAROD attenuated cell proliferation, mobility in vitro, and tumorigenicity in vivo, whereas overexpression of LNCAROD exerted opposite effects. LNCAROD is mainly distributed in nucleus and binds with YBX1 and HSPA1A proteins. Silencing either YBX1 or HSPA1A did not affect the level of LNCAROD. However, loss of LNCAROD led to shortened half‐life of YBX1 protein. Mechanistically, LNCAROD protected YBX1 from proteasomal degradation by facilitating YBX1‐HSPA1A protein–protein interaction. Depletion of HSPA1A in LNCAROD‐overexpressing cells resulted in accelerated proteasomal degradation of YBX1 protein. Moreover, re‐expression of Flag‐YBX1 in LNCAROD‐silenced cells rescued malignant behavior of HNSCC cells. Our study indicates that LNCAROD is an oncogenic lncRNA and dysregulation of m6A modification might account for aberrant expression of LNCAROD in HNSCC. LNCAROD acts as a scaffold for the interaction between YBX1 and HSPA1A, preventing proteasomal degradation of YBX1 in HNSCC cells.
Dysregulation of long noncoding RNAs (lncRNAs) is implicated in cancer development and progression. In this study, Ban et al. demonstrated that an oncogenic lncRNA, LNCAROD, is stabilized by m6A methylation and overexpressed in head and neck squamous cell carcinoma (HNSCC). LNCAROD forms a ternary complex with HSPA1A and YBX1, preventing proteasomal degradation of YBX1. This study provides a new paradigm of the mechanisms of lncRNAs in HNSCC development.
Ternary cyclodextrin (CD) complexes (drug/CD/polymer) can effectively improve the solubility of water-insoluble drugs with large size than binary CD formulations. However, ternary formulations are ...screened by a trial-and-error approach, which is laborious and material-wasting. Current research aims to develop a prediction model for ternary CD formulations by combined machine learning and molecular modeling. 596 ternary formulations data were collected to build a prediction model by machine learning. The random forest model achieved good performance with R2 = 0.887 in ST prediction and R2 = 0.815 in ST/SB prediction. Two ternary formulations (Hydrocortisone/β-CD/HPMC and dovitinib/γ-CD/CMC) were used to validate the prediction model. Molecular modeling results showed that HPMC not only warped around hydrocortisone but also prevented CD molecules from self-aggregation to increase solubility. In conclusion, a prediction model for the ternary CD formulations was successfully developed, which will significantly accelerate the formulation screening process to benefit the formulation development of water-insoluble drugs.
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•Random forest model did well in ternary cyclodextrin formulation prediction.•Factors that may impact solubilization was ranked by random forest model.•Molecular dynamic simulation was performed to investigate molecular mechanism.
Cancer stem cells (CSCs) or tumor-initiating cells (TICs) represent a small population of cancer cells with self-renewal and tumor-initiating properties. Unlike the bulk of tumor cells, CSCs or TICs ...are refractory to traditional therapy and are responsible for relapse or disease recurrence in cancer patients. Stem cells have distinct metabolic properties compared to differentiated cells, and metabolic rewiring contributes to self-renewal and stemness maintenance in CSCs.
Recent advances in metabolomic detection, particularly in hyperspectral-stimulated raman scattering microscopy, have expanded our knowledge of the contribution of lipid metabolism to the generation and maintenance of CSCs. Alterations in lipid uptake, de novo lipogenesis, lipid droplets, lipid desaturation, and fatty acid oxidation are all clearly implicated in CSCs regulation. Alterations on lipid metabolism not only satisfies the energy demands and biomass production of CSCs, but also contributes to the activation of several important oncogenic signaling pathways, including Wnt/β-catenin and Hippo/YAP signaling. In this review, we summarize the current progress in this attractive field and describe some recent therapeutic agents specifically targeting CSCs based on their modulation of lipid metabolism.
Increased reliance on lipid metabolism makes it a promising therapeutic strategy to eliminate CSCs. Targeting key players of fatty acids metabolism shows promising to anti-CSCs and tumor prevention effects.
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