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"Gu, Hao"
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Comprehensive review of recent research trends in dielectric elastomer transducers: applications, materials, and fabrication
Although rigid transducers have led to innovations in industrial automation and control systems, their rigidity limits them to the controlled environment of the factory. Recently, soft transducers have become an attractive area of research because their compliant nature has the potential to be applied to soft-bodied robots that operate in uncontrolled environments. Dielectric elastomer transducers (DETs) demonstrate large electrically-driven deformations, high energy density, fast response, long lifespans, and self-healing capabilities, making them a favorable replacement for rigid transducers. This review first introduces the working principles of DETs, modeling work, and DET configurations. Subsequently, the applications of DETs in robotics, generators, sensors, and electronics are reviewed. Finally, the challenges currently faced by DET technology are discussed and potential approaches are explored.
Journal Article
Long non-coding RNA HOTAIR knockdown enhances radiosensitivity through regulating microRNA-93/ATG12 axis in colorectal cancer
Colorectal cancer (CRC) is a global healthcare problem. Radioresistance is a huge setback for CRC radiotherapy. In this text, the roles and molecular mechanisms of long non-coding RNA HOTAIR in CRC tumorigenesis and radioresistance were further investigated. ATG12 mRNA, HOTAIR, and microRNA-93 (miR-93) levels were measured by quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay. Protein levels of LC3 I, LC3 II, p62, ATG12, cleaved caspase 3, Bax, and Bcl-2 were detected by western blotting assay in cells and were examined by immunohistochemistry (IHC) assay in tissues. Cell survival fractions, viability, and apoptotic rates were determined by clonogenic survival assay, CCK-8 assay, and flow cytometry analysis, respectively. The relationships of HOTAIR, miR-93, and ATG12 were tested by bioinformatics analysis and luciferase reporter assay. Mouse xenograft tumor models were established to investigate the influence of HOTAIR knockdown on CRC radioresistance in vivo. We found that HOTAIR expression was markedly upregulated in plasma from CRC patients after radiotherapy and CRC cells after irradiation. HOTAIR knockdown, miR-93 overexpression, or ATG12 silencing weakened cell viability, induced cell apoptosis, inhibited cell autophagy, and enhanced cell radiosensitivity in CRC. HOTAIR exerted its functions by downregulating miR-93. Moreover, HOTAIR functioned as a molecular sponge of miR-93 to regulate ATG12 expression. ATG12 protein expression was markedly upregulated and associated with miR-93 and HOTAIR expression in CRC tissues. Furthermore, HOTAIR knockdown enhanced radiosensitivity of CRC xenograft tumors by regulating miR-93/ATG12 axis. In conclusion, HOTAIR knockdown potentiated radiosensitivity through regulating miR-93/ATG12 axis in CRC, further elucidating the roles and molecular basis of HOTAIR in CRC radioresistance.
Journal Article
LPCAT1 reprogramming cholesterol metabolism promotes the progression of esophageal squamous cell carcinoma
Tumor cells require high levels of cholesterol for membrane biogenesis for rapid proliferation during development. Beyond the acquired cholesterol from low-density lipoprotein (LDL) taken up from circulation, tumor cells can also biosynthesize cholesterol. The molecular mechanism underlying cholesterol anabolism in esophageal squamous cell carcinoma (ESCC) and its effect on patient prognosis are unclear. Dysregulation of lipid metabolism is common in cancer. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) has been implicated in various cancer types; however, its role in esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, we identified that LPCAT1 is highly expressed in ESCC and that LPCAT1 reprograms cholesterol metabolism in ESCC. LPCAT1 expression was negatively correlated with patient prognosis. Cholesterol synthesis in ESCC cells was significantly inhibited following LPCAT1 knockdown; cell proliferation, invasion, and migration were significantly reduced, along with the growth of xenograft subcutaneous tumors. LPCAT1 could regulate the expression of the cholesterol synthesis enzyme, SQLE, by promoting the activation of PI3K, thereby regulating the entry of SP1/SREBPF2 into the nucleus. LPCAT1 also activates EGFR leading to the downregulation of INSIG-1 expression, facilitating the entry of SREBP-1 into the nucleus to promote cholesterol synthesis. Taken together, LPCAT1 reprograms tumor cell cholesterol metabolism in ESCC and can be used as a potential treatment target against ESCC.
Journal Article
Comparative analysis of mammalian sperm ultrastructure reveals relationships between sperm morphology, mitochondrial functions and motility
Background
Sperm morphology mainly refers to the shape of the head, the length of the flagellar segments, including the midpiece, principal piece and end piece, and the size of the accessory structures, including axonemes, outer dense fibers (ODFs), mitochondrial sheath (MS) and fibrous sheath (FS). Across species, there is considerable diversity in morphology. An established theory posits that the length of the sperm flagellum, especially the length of the midpiece, is a critical factor influencing sperm metabolism and velocity. However, our understanding of the relationships between sperm ultrastructures and the sperm flagellar length is incomplete.
Methods
The morphologies of sperm from 10 mammalian species, human, mouse, rat, dog, rabbit, goat, pig, bull, guinea pig and golden hamster, were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to the SEM and TME images, the length of sperm heads and flagellar segments, the cross-sectional areas of the accessory structures and flagella and the width of sperm heads were measured using Image J software. The variation tendencies (referred to as slope) of the accessory structures along flagella were calculated by the linear regression method. Mitochondrial functions were measured using commercial kits. The velocities of sperm were measured using CASA software.
Results
The three-dimensional morphologies of sperm from 10 species and the slopes of internal accessory structures along flagella were obtained. The width of the axoneme tapered slightly from the base to the tip of the sperm flagellum, and slopes of the axonemes correlated negatively with the variability in flagellar length across species. Additionally, the cross-sectional areas of the ODFs and/or the MS were positively correlated with the lengths of the midpiece, principal piece, and total flagellum, as well as with sperm velocities. Mitochondrial volumes were positively correlated with ATP content and sperm swimming velocities.
Conclusions
Our results not only show the relationship between sperm internal structures, flagellar length and sperm physiology but also provide sizes of mitochondria and ODFs as new targets with which to study the regulation of sperm length and velocity.
Journal Article
Characteristics and Therapeutic Potential of Human Amnion-Derived Stem Cells
Stem cells including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells (ASCs) are able to repair/replace damaged or degenerative tissues and improve functional recovery in experimental model and clinical trials. However, there are still many limitations and unresolved problems regarding stem cell therapy in terms of ethical barriers, immune rejection, tumorigenicity, and cell sources. By reviewing recent literatures and our related works, human amnion-derived stem cells (hADSCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) have shown considerable advantages over other stem cells. In this review, we first described the biological characteristics and advantages of hADSCs, especially for their high pluripotency and immunomodulatory effects. Then, we summarized the therapeutic applications and recent progresses of hADSCs in treating various diseases for preclinical research and clinical trials. In addition, the possible mechanisms and the challenges of hADSCs applications have been also discussed. Finally, we highlighted the properties of hADSCs as a promising source of stem cells for cell therapy and regenerative medicine and pointed out the perspectives for the directions of hADSCs applications clinically.
Journal Article
Three-dimensional simulation of film boiling on a horizontal surface with magnetic field
This study conducts a numerical investigation into the three-dimensional film boiling of liquid under the influence of external magnetic fields. The numerical method incorporates a sharp phase-change model based on the volume-of-fluid approach to track the liquid–vapour interface. Additionally, a consistent and conservative scheme is employed to calculate the induced current densities and electromagnetic forces. We investigate the magnetohydrodynamic effects on film boiling, particularly examining the pattern transition of the vapour bubble and the evolution of heat transfer characteristics, exposed to either a vertical or horizontal magnetic field. In single-mode scenarios, film boiling under a vertical magnetic field displays an isotropic flow structure, forming a columnar vapour jet at higher magnetic field intensities. In contrast, horizontal magnetic fields result in anisotropic flow, creating a two-dimensional vapour sheet as the magnetic strength increases. In multi-mode scenarios, the patterns observed in single-mode film boiling persist, with the interaction of vapour bubbles introducing additional complexity to the magnetohydrodynamic flow. More importantly, our comprehensive analysis reveals how and why distinct boiling effects are generated by various orientations of magnetic fields, which induce directional electromagnetic forces to suppress flow vortices within the cross-sectional plane.
Journal Article
Anisotropic flexibility and rigidification in a TPE-based Zr-MOFs with scu topology
Tetraphenylethylene (TPE)-based ligands are appealing for constructing metal-organic frameworks (MOFs) with new functions and responsiveness. Here, we report a non-interpenetrated TPE-based scu Zr-MOF with anisotropic flexibility, that is, Zr-TCPE (H
4
TCPE = 1,1,2,2-tetra(4-carboxylphenyl)ethylene), remaining two anisotropic pockets. The framework flexibility is further anisotropically rigidified by installing linkers individually at specific pockets. By individually installing dicarboxylic acid L
1
or L
2
at pocket A or B, the framework flexibility along the
b
-axis or
c
-axis is rigidified, and the intermolecular or intramolecular motions of organic ligands are restricted, respectively. Synergistically, with dual linker installation, the flexibility is completely rigidified with the restriction of ligand motion, resulting in MOFs with enhanced stability and improved separation ability. Furthermore, in situ observation of the flipping of the phenyl ring and its rigidification process is made by
2
H solid-state NMR. The anisotropic rigidification of flexibility in scu Zr-MOFs guides the directional control of ligand motion for designing stimuli-responsive emitting or efficient separation materials.
Metal-organic frameworks (MOFs) with adjustable porosity and tunable functionality have attracted considerable attention, but the directional control of intermolecular and intramolecular motion of TPE-based ligands in the non-interpenetrated flexible MOFs has not yet been studied. Here, the authors report a non-interpenetrated tetraphenylethylene-based MOF with anisotropic flexibility.
Journal Article
Vaccination induces rapid protection against bacterial pneumonia via training alveolar macrophage in mice
Vaccination strategies for rapid protection against multidrug-resistant bacterial infection are very important, especially for hospitalized patients who have high risk of exposure to these bacteria. However, few such vaccination strategies exist due to a shortage of knowledge supporting their rapid effect. Here, we demonstrated that a single intranasal immunization of inactivated whole cell of Acinetobacter baumannii elicits rapid protection against broad A. baumannii -infected pneumonia via training of innate immune response in Rag1 -/- mice. Immunization-trained alveolar macrophages (AMs) showed enhanced TNF-α production upon restimulation. Adoptive transfer of immunization-trained AMs into naive mice mediated rapid protection against infection. Elevated TLR4 expression on vaccination-trained AMs contributed to rapid protection. Moreover, immunization-induced rapid protection was also seen in Pseudomonas aeruginosa and Klebsiella pneumoniae pneumonia models, but not in Staphylococcus aureus and Streptococcus pneumoniae model. Our data reveal that a single intranasal immunization induces rapid and efficient protection against certain Gram-negative bacterial pneumonia via training AMs response, which highlights the importance and the possibility of harnessing trained immunity of AMs to design rapid-effecting vaccine.
Journal Article
M2 microglia-derived exosomes reduce neuronal ferroptosis via FUNDC1-mediated mitophagy by activating AMPK/ULK1 signaling
Neuronal ferroptosis plays a vital role in the progression of neonatal hypoxic-ischemic brain damage (HIBD). M2-type microglia-derived exosomes (M2-exos) have been shown to protect neurons from ischemia–reperfusion (I/R) brain injury, but their impact on I/R-induced neuronal ferroptosis and the underlying mechanisms remain poorly understood. In this study, we used an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model in HT-22 neuronal cells to investigate how M2-exos modulate ferroptosis. We found that M2-exos were internalized by HT-22 cells and significantly attenuated OGD/R-induced ferroptosis. Mechanistically, M2-exos enhanced mitophagy, which was mediated by the upregulation of FUN14 domain-containing protein 1 (FUNDC1), thereby inhibiting ferroptosis. Further analysis revealed that M2-exos activated FUNDC1-dependent mitophagy through the AMP-activated protein kinase (AMPK)/UNC-51-like kinase 1 (ULK1) signaling pathway. Taken together, these findings suggest that M2-exos ameliorate I/R-induced neuronal ferroptosis by enhancing FUNDC1-mediated mitophagy through the activation of AMPK/ULK1 signaling pathway.
Journal Article