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Aims: Peripheral immune cells infiltrating into the brain trigger neuroinflammation after an ischemic stroke. Partial immune cells reprogram their function for neural repair. Which immune cells promote ischemic brain recovery needs further identification. Methods: We performed single‐cell transcriptomic profiling of CD45high immune cells isolated from the ischemic hemisphere at subacute (5 days) and chronic (14 days) stages after ischemic stroke. Results: A subset of phagocytic macrophages was associated with neuron projection regeneration and tissue remodeling. We also identified a unique type of T cells with highly expressed macrophage markers, including C1q, Apoe, Hexb, and Fcer1g, which showed high abilities in tissue remodeling, myelination regulation, wound healing, and anti‐neuroinflammation. Moreover, natural killer cells decreased cytotoxicity and increased energy and metabolic function in the chronic stage after ischemic stroke. Two subgroups of neutrophils upregulated CCL signals to recruit peripheral immune cells and released CXCL2 to keep self‐recruiting at the chronic stage. Conclusions: We identified subsets of peripheral immune cells that may provide potential therapeutic targets for promoting poststroke recovery. [ABSTRACT FROM AUTHOR]

The absence of blood vessels in tissue engineered bone often leads to necrosis of internal cells after implantation, ultimately affecting the process of bone repair. Herein, mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured to induce osteogenesis and angiogenesis. Based on the findings, the number of HUVECs in the coculture system increased in the growth medium group, but decreased in the osteogenic induction medium (OIM) group. Considering that the paracrine effects of MSCs had changed, we tested the genes expression of osteogenically differentiated MSCs. The expression of osteogenic genes in MSCs increased during osteogenesis. Further, the expression levels of pigment epithelial‐derived factor (PEDF) gene and protein, an antivascular factor, were also increased. To verify whether MSCs promote HUVECs apoptosis via PEDF, PEDF was silenced via siRNA. The conditioned medium of differentiated MSCs with PEDF silencing significantly improved the proliferation and apoptosis of HUVECs. Based on further experiments, PEDF mediated the apoptosis and proliferation of HUVECs through p53, BAX/BCL‐2, FAS, and c‐Caspase‐3. However, when PEDF was silenced with siRNA, the osteogenic potential of MSCs was affected. The results of this study provide a theoretical basis for the construction of prevascularized bone tissues in vitro. [ABSTRACT FROM AUTHOR]

The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) Active Power Filter (APF); this paper analyzes the causes of unbalanced neutral point voltage and studies the reason of the unbalance of the neutral point voltage. A novel neutral point voltage control strategy using Space Vector Pulse Width Modulation (SVPWM) is proposed. The proposed strategy is based on the traditional SVPWM, by controlling the effect time of small vector, which can change the state of the midpoint voltage fluctuation, and the neutral point voltage can be maintained balance. The influence of the vector on neutral point balance is investigated in depth. Simulation results show the neutral point voltage balancing control strategy based on SPWM is effective.

To design titanium (Ti)-based biomaterials with controlled drug-releasing bioactive property, TiO2 nanotubes with a diameter of approximately 110 nm was fabricated by electrochemical anodization. TiO2 nanotubes were then loaded with naringin by direct dropping and coated with chitosan layers. The surface morphologies, chemical compositions and wettability of different substrates were characterized by field emission scanning electron microscopy, atomic force microscope, X-ray photoelectron spectroscopy and contact angle measurement, respectively. The in vitro release behavior of naringin was evaluated by UV-visible-spectrophotometer. The biological properties of osteoblasts on different substrates were investigated in vitro. Our results indicate that the chitosan-coated naringin-loaded TiO2 nanotubes enhanced osteoblast spreading, proliferation, alkaline phosphatase activity and late-stage osteoblast mineralization. This study provides a platform to help enhance osteointegration between the bone and implant surface in clinical applications. [ABSTRACT FROM AUTHOR]

Cardiovascular disease has become a great threat to the health of mankind; current titanium (Ti) stents fail due to late stent thrombosis caused by the lack of re-endothelialization of the Ti stent. The objective of this study was to design a novel cardiovascular Ti implant with improved surface biocompatibility. TiO2 nanotubes with a diameter of 110 nm were anodized at a constant voltage of 30 V, and fibronectin was immobilized onto the TiO2 nanotubes using polydopamine. The element composition, morphology, and wettability of the different substrate surfaces were characterized by x-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and contact angle measurements, respectively, confirming the successful immobilization of fibronectin. In vitro experiments including immunofluorescence staining, Cell Counting Kit-8 (CCK-8), and nitric oxide (NO) and prostacyclin (PGI2) release demonstrate that fibronectin modified TiO2 nanotubes supported cell adhesion, proliferation, and normal cellular functions of human umbilical vein endothelial cells (HUVECs). These methodologies can be applied for future fabrication of cardiovascular stents. [ABSTRACT FROM AUTHOR]

To control the sustained release of melatonin and modulate the osteogenic differentiation of mesenchymal stem cells (MSCs), melatonin was firstly loaded onto TiO2nanotubes by direct dropping method, and then a multilayered film was coated by a spin-assisted layer-by-layer technique, which was composed of chitosan (Chi) and gelatin (Gel). Successful fabrication was characterized by field emission scanning electron microscopy, atomic force microscope, X-ray photoelectron spectroscopy and contact angle measurement, respectively. The efficient sustained release of melatonin was measured by UV-visible-spectrophotometer. After 2 days of culture, well-spread morphology was observed in MSCs grown on the Chi/Gel multilayer-coated melatonin-loaded TiO2nanotube substrates as compared to different groups. After 4, 7, 14 and 21 days of culture, the multilayered-coated melatonin-loaded TiO2nanotube substrates increased cell proliferation, increased alkaline phosphatase (ALP) and mineralization, increased expression of mRNA levels for runt-related transcription factor 2 (Runx2), ALP, osteopontin (OPN) and osteocalcin (OC), indicative of osteoblastic differentiation. These results demonstrated that Chi/Gel multilayer-coated melatonin-loaded TiO2nanotube substrates promoted cell adhesion, spreading, proliferation and differentiation and could provide an alternative fabrication method for titanium-based implants to enhance the osteointegration between bone tissues and implant surfaces. [ABSTRACT FROM PUBLISHER]

Titanium (Ti) is widely used as orthopedic implant materials. TiO 2 nanotubes (TNTs) further improve the bioactivity of Ti, which enhance the osteogenic differentiation of mesenchymal stem cells (MSCs). However, the underlying mechanism is still unclear. In this study, we verified the response of MSCs on Ti and TNT substrates and explored the regulatory mechanism of long non-coding RNAs (lncRNAs). LncRNA and mRNA expression profiles were analyzed via RNA sequencing. Differential lncRNA and mRNA expression and predicted target genes of lncRNAs were performed by bioinformatics analysis. 1075 up-regulated and 1301 down-regulated genes, 26 up-regulated and 35 down-regulated lncRNAs were obtained according to the RNA-Seq. Expression of 8 lncRNAs were verified by qPCR, which was consistent with the sequencing data. To explore the function and target gene of lncRNA, lncRNA CCL3-AS and gene CCL3 were selected for further investigation. The fluorescence staining, alkaline phosphatase (ALP) activity and CCK-8 assay were performed. Besides, expressions of runt-related transcription factor 2 (Runx2), collagen type I (Col I), osteopontin (OPN) were detected by qPCR and western blot. These results indicate that lncRNA CCL3-AS could inhibit the osteogenic differentiation and enhance cell viability of MSCs on the TNT substrates, which was dependent on the regulation of CCL3. This study supplied a comprehensive understanding for further study using lncRNA modulators to surface design of titanium for enhancing osseointegration., (Copyright © 2019 Elsevier B.V. All rights reserved.)

To design titanium (Ti)-based biomaterials with controlled drug-releasing bioactive property, TiO 2 nanotubes with a diameter of approximately 110 nm was fabricated by electrochemical anodization. TiO 2 nanotubes were then loaded with naringin by direct dropping and coated with chitosan layers. The surface morphologies, chemical compositions and wettability of different substrates were characterized by field emission scanning electron microscopy, atomic force microscope, X-ray photoelectron spectroscopy and contact angle measurement, respectively. The in vitro release behavior of naringin was evaluated by UV-visible-spectrophotometer. The biological properties of osteoblasts on different substrates were investigated in vitro. Our results indicate that the chitosan-coated naringin-loaded TiO 2 nanotubes enhanced osteoblast spreading, proliferation, alkaline phosphatase activity and late-stage osteoblast mineralization. This study provides a platform to help enhance osteointegration between the bone and implant surface in clinical applications.

Cardiovascular disease has become a great threat to the health of mankind; current titanium (Ti) stents fail due to late stent thrombosis caused by the lack of re-endothelialization of the Ti stent. The objective of this study was to design a novel cardiovascular Ti implant with improved surface biocompatibility. TiO 2 nanotubes with a diameter of 110 nm were anodized at a constant voltage of 30 V, and fibronectin was immobilized onto the TiO 2 nanotubes using polydopamine. The element composition, morphology, and wettability of the different substrate surfaces were characterized by x-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and contact angle measurements, respectively, confirming the successful immobilization of fibronectin. In vitro experiments including immunofluorescence staining, Cell Counting Kit-8 (CCK-8), and nitric oxide (NO) and prostacyclin (PGI2) release demonstrate that fibronectin modified TiO 2 nanotubes supported cell adhesion, proliferation, and normal cellular functions of human umbilical vein endothelial cells (HUVECs). These methodologies can be applied for future fabrication of cardiovascular stents.