► We synthesized expanded graphite oxide by a modified Hummers approach. ► The structure of expanded graphite can be easily and remarkably disordered by oxidation. ► The addition of expanded graphite ...oxide improved the thermal stability of silicone rubber evidently.
Graphite oxide was synthesized by the oxidation of expanded graphite via a modified Hummers approach. The structure of graphite oxide was evaluated by TEM, XRD, Raman and FTIR. It was found that the structure of expanded graphite can be easily and remarkably disordered by oxidation. Silicone rubber/GO nanocomposites were prepared via a solution intercalation method. The structure of the nanocomposites was studied by XRD. The thermal behavior of the nanocomposites was characterized by TGA and the results showed that the addition of graphite oxide is beneficial to improve the thermal stability of the nanocomposites at high temperature.
A 3D point cloud describes the real scene precisely and intuitively. To date how to segment diversified elements in such an informative 3D scene is rarely discussed. In this paper, we first introduce ...a simple and flexible framework to segment instances and semantics in point clouds simultaneously. Then, we propose two approaches which make the two tasks take advantage of each other, leading to a win-win situation. Specifically, we make instance segmentation benefit from semantic segmentation through learning semantic-aware point-level instance embedding. Meanwhile, semantic features of the points belonging to the same instance are fused together to make more accurate per-point semantic predictions. Our method largely outperforms the state-of-the-art method in 3D instance segmentation along with a significant improvement in 3D semantic segmentation. Code has been made available at: https://github.com/WXinlong/ASIS.
Stem cell–based therapies can potentially regenerate many types of tissues and organs, thereby providing solutions to a variety of diseases and injuries. However, acute cell death, uncontrolled ...differentiation, and low functional engraftment yields remain critical obstacles for clinical translation. Advanced functional biomaterial scaffolds that can deliver stem cells to the targeted tissues/organs and promote stem cell survival, differentiation, and integration to host tissues may potentially transform the clinical outcome of stem cell–based regenerative therapies. In this review, the authors briefly summarize sources of stem cells for transplantation, present the current state of the art in biomaterial design for stem cell delivery, and provide critical analysis for existing materials. Applications to the cardiovascular, neural, and musculoskeletal systems are highlighted with recent nonclinical studies and clinical trials. The authors also discuss how advances in biomaterials research can contribute to regenerative medicine research and stem cell therapies.
The design and fabrication strategies of biomaterials used for stem cell delivery are critically affecting the therapeutic efficacy of stem cell–based therapy. This review focuses on recent development in advanced functional biomaterials for stem cell delivery and their application in nonclinical and clinical repair and regeneration of cardiovascular, neural, and musculoskeletal systems.
Acceptor alloys based on n‐type small molecular and fullerene derivatives are used to fabricate the ternary solar cell. The highest performance of optimized ternary device is 10.4%, which is the ...highest efficiency for one donor/two acceptors‐based ternary systems. Three important parameters, JSC, VOC, and FF, of the optimized ternary device are all higher than the binary reference devices.
A rational synthetic strategy to construct two supramolecular isomers based on polyoxovanadate organic polyhedra with tetrahedral symmetries is presented. VMOP‐α, a low‐temperature product, has an ...extremely large cell volume (470 842 Å3), which is one of the top three for well‐defined MOPs. The corner‐to‐corner packing of tetrahedra leads to a quite low density of 0.174 g cm−3 with 1D channels (ca. 5.4 nm). The effective pore volume is up to 93.6 % of cell volume, nearly the largest found in MOPs. For the high‐temperature outcome, VMOP‐β, the cell volume is only 15 513 Å3. The packing mode of tetrahedra is corner‐to‐face, giving rise to a high‐density architecture (1.324 g cm−3; channel 0.8 nm). Supramolecular structural transformation between VMOP‐α and VMOP‐β can be reversibly achieved by temperature‐induced solvent‐mediated transformation. These findings give a good opportunity for understanding 3D supramolecular aggregation and crystal growth based on large molecular tectonics.
Two genuine supramolecular isomers based on nanoscale polyoxovanadate–organic polyhedra with truncated tetrahedral geometry were synthesized. Reversible structural transformation between kinetic and thermodynamic isomers was achieved by temperature‐induced solvent‐mediated transformation.
Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005-0.02 Hz), neurogenic (N; 0.02-0.04 Hz), and myogenic (M; 0.04-0.2 Hz) frequency bands. In this study, we ...quantified changes in prefrontal concentrations of oxygenated hemoglobin (ΔHbO) and redox-state cytochrome c oxidase (ΔCCO) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the prefrontal cortex (PFC). Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.
Gold nanoparticles (AuNPs) have been extensively explored for biomedical applications due to their advantages of facile synthesis and surface functionalization. Previous studies have suggested that ...AuNPs can induce differentiation of stem cells into osteoblasts. However, how the size and shape of AuNPs affect the differentiation response of stem cells has not been elucidated. In this work, a series of bovine serum albumin (BSA)-coated Au nanospheres, Au nanostars and Au nanorods with different diameters of 40, 70 and 110 nm were synthesized and their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) were investigated. All the AuNPs showed good cytocompatibility and did not influence proliferation of hMSCs at the studied concentrations. Osteogenic differentiation of hMSCs was dependent on the size and shape of AuNPs. Sphere-40, sphere-70 and rod-70 significantly increased the alkaline phosphatase (ALP) activity and calcium deposition of cells while rod-40 reduced the ALP activity and calcium deposition. Gene profiling revealed that the expression of osteogenic marker genes was down-regulated after incubation with rod-40. However, up-regulation of these genes was found in the sphere-40, sphere-70 and rod-70 treatment. Moreover, it was found that the size and shape of AuNPs affected the osteogenic differentiation of hMSCs through regulating the activation of Yes-associated protein (YAP). These results indicate that the size and shape of AuNPs had an influence on the osteogenic differentiation of hMSCs, which should provide useful guidance for the preparation of AuNPs with defined size and shape for their biomedical applications.
Cell chirality has been demonstrated to be important for controlling cell functions. However, it is not clear how the chirality of the extracellular microenvironment regulates cell adhesion and ...cytoskeletal structures and therefore affects gene transfection. In this study, the chirality of focal adhesions and the cytoskeleton of single human mesenchymal stem cells (hMSCs) was controlled by specially designed micropatterns, and its influence on gene transfection was investigated. Micropatterns with different cell adhesion areas and swirling stripe lines were prepared by micropatterning fibronectin on polystyrene surfaces. The chiral micropatterns induced the formation of chiral focal adhesions and chiral cytoskeletal structures. Gene transfection efficiency was enhanced with increasing adhesion area, while hMSCs on left-handed and right-handed swirling micropatterns showed the same level of gene transfection. When the swirling angle was changed from 0°, 30°, and 60° to 90°, the gene transfection efficiency at a swirling angle of 60° was the lowest. The influence of cell chirality on gene transfection was strongly associated with cellular uptake capacity, DNA synthesis and cytoskeletal mechanics. The results demonstrated that cytoskeletal swirling had a significant influence on gene transfection.
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•Chiral micropatterns were prepared from photo-reactive PVA through photolithography.•Cell chirality was controlled by the micropatterns.•The influence of cell chirality on exogenous gene transfection was investigated.•The swirling angle of cell chirality significantly affected transfection efficiency.•Different transfection efficiency was associated with cell mechanics and activity.
Design and synthesis of metal–organic polyhedra (MOPs) with targeted geometries from predetermined secondary building units (SBUs) is a long‐standing challenge in chemistry and material science. ...Theoretical prediction shows that there are 6 possible polyhedra from the 3‐coordinated, 4‐coordinated octahedron ((3,4)‐c octahedron) to (3,5)‐c icosahedron with minimal transitivity (simplest possible). Except for one missing polyhedron (mtr) due to the unfavorable angles, we report five MOPs based on these structures, including an octahedral (3,4)‐c VMOP‐21 (rdo), an icosahedral (3,5)‐c VMOP‐25 (trc), and three intermediate derived trinodal (3,4,5)‐c VMOP‐22–24 (ghm, hmg, xum). Remarkably, all these MOPs obey the minimal transitivity principle and are consistent with geometrical predictions.
Get the MOP: The concept of reticular chemistry is used for the design of metal–organic polyhedra (MOPs) leading to a sequence of theoretically expected and experimentally characterized 3‐coordinated, 4‐coordinated and 5‐coordinated MOPs based on polyoxovanadate building blocks that all obey the minimal transitivity (simplest possible) principle.
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