14 research outputs found

    Sustained Release of IGF-1 by 3D Mesoporous Scaffolds Promoting Cardiac Stem Cell Migration and Proliferation

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    Background/Aims: C-kit-positive cardiac stem cells (CSCs) may have potential as a treatment for cardiovascular disease. However, the low survival rates of c-kit-positive CSCs present a major challenge during the transplantation process. Methods: The hierarchical structure of the 3D cell scaffold was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and N2 adsorption-desorption isotherms. Analyses of the proliferation and migration performances of the IGF-1 scaffold on c-kit-positive CSCs were conducted by experiments including QuantiT PicoGreen dsDNA and transwell assays. Results: In this study, we synthesized for the first time a novel hierarchical macro-mesoporous silica material (denoted MS15-c) in a one-pot procedure for the release of insulin-like growth factor-1 (IGF-1) and a three-dimensional (3D) cell scaffold. Both macropores and mesopores were visible in MS15-c and enabled the sustained release of IGF-1, extending its half-life and enhancing CSC proliferation and migration. Proliferation and migration were detected by QuantiT PicoGreen dsDNA and transwell assays, respectively. Moreover, an in vivo experiment was conducted to detect heart function with the addition of MS15-c. The new strategy proposed in this paper may extend the bio-applications of 3D cell scaffolds, thus permitting the sustained release of growth factors and efficient promotion of cell proliferation. Conclusion: This work successfully demonstrated an effective strategy for the construction of MS15-c cell scaffolds with hierarchical macro-mesoporous structures. The macro-mesoporous structures gave cell scaffolds the ability to release a growth factor to facilitate cell growth, while the scaffold structure promoted cell proliferation

    Model-Free Optimal Control for Affine Nonlinear Systems With Convergence Analysis

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    Effect of pyrolysis temperature on the transformation of phosphorus forms in sludge biochar

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    The Standards, Measurements, and Testing (SMT) phosphorus fractionation approach was used to measure the amounts of total phosphorus (TP), organic phosphorus (OP), inorganic phosphorus (IP), apatite inorganic phosphorus (AP), and non-apatite inorganic phosphorus (NAIP) in sludge biochar. Sludge biochar was characterized using methods such as X-ray diffraction, elemental analysis, and Fourier transform infrared spectroscopy. The findings showed that IP content increased significantly after pyrolysis, reaching up to 97% of TP content at the optimal temperature of 350 °C. Furthermore, when the pyrolysis temperature increased, the AP/IP ratio showed fluctuations between decreases and increases, maximum at 60%. The results of the correlation analysis indicate that IP has a positive correlation with yield, pH, and S elements (p < 0.05) and a negative correlation with N, C, and H elements (p < 0.01). OP, on the other hand, has a positive correlation with H elements (p < 0.05) and a negative correlation with yield (p < 0.01). Furthermore, TP, NAIP, and AP all show negative correlations with N, C, and H elements (p < 0.01), with TP and NAIP also displaying negative correlations with pH and S elements (p < 0.05). HIGHLIGHT Phosphorus morphology changes at 300–700 °C by the Standards, Measurements, and Testing method. Different temperatures change the transformation of various phosphorus forms. The apatite inorganic phosphorus content in biochar increased with the increase of pyrolysis temperature and reached the maximum at 700 °C.

    Ultrathin Carbon Nanosheets for Highly-efficient Capacitive K-ion and Zn-ion Storage

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    Porous carbon has attracted extensive attentions as the electrode material for various energy storage devices considering its advantages like high theoretical capacitance/capacity, high conductivity, low cost and earth abundant inherence. However, there still exists some disadvantages limiting its further applications, such as the tedious fabrication process, limited metal-ion transport kinetics and undesired structure deformation at harsh electrochemical conditions. Herein, we report a facile strategy, with calcium gluconate firstly reported as the carbon source, to fabricate ultrathin porous carbon nanosheets. The as-prepared Ca-900 electrode delivers excellent K-ion storage performance including high reversible capacity (430.7 mAh g-1), superior rate capability (154.8 mAh g-1 at an ultrahigh current density of 5.0 A g-1) and ultra-stable long-term cycling stability (a high capacity retention ratio of ~81.2% after 4000 cycles at 1.0 A g-1). Similarly, when being applied in Zn-ion capacitors, the Ca-900 electrode also exhibits an ultra-stable cycling performance with ~90.9% capacity retention after 4000 cycles at 1.0 A g-1, illuminating the applicable potentials. Moreover, the origin of the fast and smooth metal-ion storage is also revealed by carefully designed consecutive CV measurements. Overall, considering the facile preparation strategy, unique structure, application flexibility and in-depth mechanism investigations, this work will deepen the fundamental understandings and boost the commercialization of high-efficient energy storage devices like potassium-ion/sodium-ion batteries, zinc-ion batteries/capacitors and aluminum-ion batteries.</p

    Numerical study on the uniform distribution of flow field of airflow dryer

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    The uniformity of hot air flow inside the airflow dryer not only affects the moisture distribution at the outlet, but also affects the quality of the product. Based on the guide plate structure of the SH23A airflow tobacco dryer, a gradient curved guide plate dryer is designed, and the flow field distribution of the dryer is numerically investigated under different flow distribution conditions at the hot air inlet and flue gas inlet. The results show that the airflow uniformity is affected by the flow distribution at the inlet of the heated air and the inlet of the cigarette smoke, the structure of the guide plate, etc., the non-uniformity coefficient decreases with the increase of hot air inlet flow rate. The non-uniformity coefficient of tapered arc deflector decreases by 9–12 %

    Effect of hydrothermal temperature on the optical properties of hydrochar-derived dissolved organic matter and their interactions with copper (II)

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    Abstract Hydrothermal carbonization (HTC) has been regarded as a promising technique for turning wet biomass into hydrochar due to its low energy consumption, low exhaust gas emissions, etc. In addition, hydrochar is an important source of dissolved organic matter (DOM), which plays a crucial part in the migration and destiny of pollutants in the environmental medium. However, there are limited studies that focus on the factors that influence the formation of DOM in hydrochar, such as hydrothermal temperature. Therefore, the current study comprehensively characterized the optical properties of DOM within hydrochar derived from sawdust (HDOM) under different hydrothermal temperatures (150–300 °C) by Ultraviolet–visible (UV–Vis) and fluorescence spectroscopy, as well as its complexation characteristic with Cu(II). The findings revealed that the organic carbon content of HDOM reached a peak of 37.3 mg L−1 when the temperature rose to 240 °C and then decreased as the temperature increased. UV–Vis spectroscopy analysis showed that the absorption capacity of HDOM at 275 nm increases with temperature and reaches a maximum value at 240 °C, indicating that high temperature promotes the formation of monocyclic aromatic compounds. High temperature enhances the aromaticity, hydrophobicity, and humification degree of HDOM, thus improving its stability and aromaticity. The E3/E4 ratios are all greater than 3.5, confirming that the main component of HDOM is fulvic acid, which corresponds to 3D-EEM and Pearson's correlation coefficient analysis. The humification index (HIX) of HDOM increased with the rise in hydrothermal temperature (150–240 °C), as observed by the three-dimensional excitation-emission matrix spectroscopy (3D-EEMs). After reaching its peak at 240 °C, the HIX value gradually dropped in line with the trend of the DOC change. Moreover, the bioavailability (BIX) value of DOM was all high and greater than 1, indicating all the HDOM are readily bioavailable. Two microbial humic substances (C1 and C4), a humic-like substance (C2), and a protein-like substance (C3) were discovered in DOM by integrating 3D-EEMs with parallel factor analysis (PARAFAC). Their fluorescence intensity decreases as the Cu(II) concentration increases, indicating the formation of complexes with Cu(II). As the temperature rises, the binding ability of DOM and Cu(II) changes significantly, reaching the optimum at 300 °C. Meanwhile, the substance C2 has the strongest binding ability with Cu(II). This research emphasizes the significance of spectroscopy analysis in determining the evolution of hydrochar-derived DOM, the potential for heavy metal binding and migration, and its characteristics and features. Graphical Abstrac

    Room-temperature nonvolatile molecular memory based on partially unzipped nanotube

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    Nonvolatile memories have attracted a lot of interest because they retain the data when the power is interrupted. Smaller size and improved performance of nonvolatile memories are pursued both for basic research and applications. In this work, a molecular wire made of seamless junctions between semiconducting single-walled carbon nanotubes (SWNT) and partially unzipped segments of the SWNTs are reported. This novel nanostructure is demonstrated to be a nonvolatile memory, which works at room temperature under atmospheric conditions. The characteristics of the device are measured with a four-terminal configuration and a non-local voltage (Vnon-local) is used as the storage signal. An electrical hysteresis of Vnon-local is observed, wherein two states with different Vnon-local can be switched by the application of an electric field through an insulating gate device structure, exhibiting nonvolatile characteristics. Vnon-local can be modulated with external magnetic fields and the mechanism of the electrical hysteresis is attributed to the magnetic moments at the partially unzipped SWNT. The smaller size of SWNT and high working temperature may lead to the development of molecular nanomagnets as nonvolatile memory devices for practical applications.Supported by Major Nanoprojects of Ministry of Science and Technology of China (Grant Nos.2018YFA0208403, 2017YFA0207104), National Natural Science Foundation of China (21973021, 11874129), the GBA National Institute for Nanotechnology Innovation, Guangdong, China (2020B0101020003), CAS Project for Young Scientists in Basic Research (YSBR-030), Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB36000000, NBSDC-DB-18)
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