The development of two-dimensional (2D) semiconductors is limited by the lack of doping methods. We propose surface isovalent substitution as an efficient doping mechanism for 2D semiconductors by revealing the evolution of the structure and electronic properties of 2D Se/Te. Because of the different electronegativity of Se and Te, Se substitution for Te at the specific lattice sites introduces electric dipoles and leads to charge redistribution, which lowers the work function and tunes the Te films from p-type to n-type semiconductors.
View Article and Find Full Text PDFEnhanced electronic coupling gives rise to many intriguing properties in π-d conjugated metal-organic frameworks (CMOFs). By low-temperature scanning tunneling microscopy and density functional theory calculation, we investigate the electronic coupling in one-dimensional (1D) π-d conjugated FeQDI polymers. Our experiments have resolved the bulk and end states stemming from Fe atoms in different coordination environments and their spatial extension due to π-d conjugation.
View Article and Find Full Text PDFPhonon splitting of the longitudinal and transverse optical modes (LO-TO splitting), a ubiquitous phenomenon in three-dimensional polar materials, will break down in two-dimensional (2D) polar systems. Theoretical predictions propose that the LO phonon in 2D polar monolayers becomes degenerate with the TO phonon, displaying a distinctive "V-shaped" nonanalytic behavior near the center of the Brillouin zone. However, the full experimental verification of these nonanalytic behaviors has been lacking.
View Article and Find Full Text PDFDue to the diversity of molecular building blocks, the two-dimensional (2D) metal-organic frameworks (MOFs) are ideal platforms to realize exotic lattice models in condensed matter theory. In this work, we demonstrate the universal existence of topological corner states in 2D MOFs with a star lattice configuration, and confirm the intriguing higher-order nontrivial topology in the energy window between two Kagome-bands, or between Dirac-band and four-band. Furthermore, combining first-principles calculations and scanning tunneling microscopy measurements, the unique topological corner state is directly identified in monolayer Ni(HITP) (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) grown on the Au(111) substrate.
View Article and Find Full Text PDFA single-layer Cr (HITP) (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) conjugated metal-organic framework (c-MOF) is synthesized under ultrahigh vacuum conditions by substituting Cr for Ni in Ni (HITP) template. As revealed by low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy, while codeposition of Cr atoms and 2,3,6,7,10,11-hexaaminotriphenylene precursors produces irregular branches, crystalline Cr (HITP) frameworks are obtained by depositing Cr atoms to the Ni (HITP) templates. The density functional theory calculations reveal that the binding energy between Cr and HITP ligands is much higher than that for Ni, which hampers the growth of crystalline Cr (HITP) frameworks through direct coordination assembly but makes the substitution reaction energetically favorable.
View Article and Find Full Text PDFActa Biochim Biophys Sin (Shanghai)
March 2022
Tetraspanin CD82 often participates in regulating the function of epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-Met). Palmitoylation is a post-translational modification that contributes to tetraspanin web formation and affects tetraspanin-dependent cell signaling. However, the molecular mechanisms by which CD82 palmitoylation affects the localization and stability of EGFR and c-Met have not yet been elucidated.
View Article and Find Full Text PDFThe Yes-associated protein (YAP) transcription co-activator is recognized as a key mediator and has been implicated in the regulation of stem cell fate; however, the role of YAP in the tenogenic differentiation of mesenchymal stem cells (MSCs) is not well understood. In the present study, we characterized tenogenic differentiation of C3H10T1/2 cells induced by BMP-12 and evaluated the function of YAP in the regulation of the BMP-12-induced tenogenesis. We found that the tendon-related proteins Scleraxis, Tenascin C, and Tenomodulin were significantly increased after induction by 10 ng/ml BMP-12 for 48 h in C3H10T1/2 cells.
View Article and Find Full Text PDFIn the pursuit of manipulating the properties of single atoms, the surface-supported metal-organic frameworks (MOFs) provide us opportunities to individually address the electronic and magnetic properties of coordinated metal atoms by scanning tunneling microscopy. Recently, we have synthesized Ni-TPyP (TPyP = 5,10,15,20-tetra-(4-pyridyl) porphyrin) networks with dinuclear Ni centers on a Au(111) surface, in which the top-Ni atoms are sitting above the molecular plane. Here, we investigate the top-Ni atoms and their hydrogenated derivatives by low-temperature scanning tunneling microscopy and spectroscopy, and show that the electronic and magnetic states of top-Ni atoms can be manipulated by hydrogen adsorption.
View Article and Find Full Text PDFOwing to an error that was made during the production stages of the above review article, what was actually Fig. 2 was inadvertently duplicated on p. 7 as Fig.
View Article and Find Full Text PDFStem cells receive cues from their physical and mechanical microenvironment via mechanosensing and mechanotransduction. These cues affect proliferation, self‑renewal and differentiation into specific cell fates. A growing body of evidence suggests that yes‑associated protein (YAP) and transcriptional coactivator with PDZ‑binding motif (TAZ) mechanotransduction is key for driving stem cell behavior and regeneration via the Hippo and other signaling pathways.
View Article and Find Full Text PDFCD82, a member of the tetraspanin superfamily, has been proposed to exert its activity via tetra-transmembrane protein enriched microdomains (TEMs) in exosomes. The present study aimed to explore the potential of the exosome protein CD82 in diagnosing breast cancers of all stages and various histological subtypes in patients. The results strongly suggest that CD82 expression in breast cancer tissue was significantly lower than that in healthy and benign breast disease tissues.
View Article and Find Full Text PDFChemotherapeutic insensitivity remains a major obstacle to osteosarcoma treatment. Recently, increasing evidence has suggested that long non-coding RNAs (lncRNAs) play an essential role in tumourigenesis. However, the potential biological roles and regulatory mechanisms of novel lncRNAs in response to cisplatin treatment are poorly understood.
View Article and Find Full Text PDFDue to the low proliferative and migratory capacities of chondrocytes, cartilage repair remains a challenging clinical problem. Current therapeutic strategies for cartilage repair result in unsatisfactory outcomes. Autologous chondrocyte implantation (ACI) is a cell based therapy that relies on the in vitro expansion of healthy chondrocytes from the patient, during which proliferation‑promoting factors are frequently used.
View Article and Find Full Text PDFCartilage defect is an intractable clinical problem. Therapeutic strategies for cartilage repair are far from optimal due to poor proliferation capacity of chondrocytes. Autologous chondrocyte implantation is a cell based therapy that uses in vitro amplified healthy chondrocytes from the patient.
View Article and Find Full Text PDFThe Yes‑associated protein (YAP) transcriptional coactivator is recognized as a crucial regulator of human cancer. However, its involvement in human non‑small cell lung cancer (NSCLC) in response to physical cues remains unclear. In this study, substrates with different rigidity were generated in order to evaluate the role of YAP, and its upstream regulators in the Hippo pathway, in the regulation of growth of an NSCLC cell line within particular environments.
View Article and Find Full Text PDFZhongguo Xiu Fu Chong Jian Wai Ke Za Zhi
January 2014
Objective: To review the chondrocyte survival microenvironment and the research progress of the application of microfluidic chips in constructing the chondrocyte microenvironment.
Methods: Recent literature about the role of microenvironment in the regulation of chondrocytes and the application of microfluidic chips in constructing the chondrocyte microenvironment was reviewed and analyzed.
Results: Regulating the microenvironment of chondrocyte mainly involves extracellular matrix microenvironment, mechanical microenvironment, electric microenvironment, and hypoxic microenvironment.
Ganglioside GM3 plays a well-documented and important role in the regulation of tumor cell proliferation, invasion, and metastasis by modulating tyrosine kinase growth factor receptors. However, the effect of GM3 on the hepatocyte growth factor receptor (HGFR, cMet) has not been fully delineated. In the current study, we investigated how GM3 affects cMet signaling and HGF-stimulated cell motility and migration using three hepatic cancer cell lines of mouse (Hca/A2, Hca/16A3, and Hepa1-6).
View Article and Find Full Text PDFAlgal assay using marine microalgae has emerged as an important method to evaluate the toxicity of chemicals, which is currently undertaken using conventional culture and additional detection of physiological cellular endpoints. While effective, this approach can be labor-intensive and thus could benefit from a more streamlined, integrated approach. Microfluidics offers a way to accomplish this goal.
View Article and Find Full Text PDFIn native fibrocartilage, mechanotransduction allows the cells to perceive the physical microenvironment not only through topographical cues from the extracellular matrix, but also through mechanical cues, such as interstitial flow. To create a microenvironment that simultaneously integrates nanotopography and flow stimulus, we developed a biomimetic microfluidic device embedded with aligned nanofibers to contain microchambers of different angles, which enabled the flow direction to form different angles with the fibers. Using this device, we investigated the effects of microfluidic and nanotopographical environment on the morphology and fibrochondrogenesis of mesenchymal stem cells (MSCs) and the involvement of RhoA/ROCK pathway and Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ).
View Article and Find Full Text PDFMatrix elasticity exerts considerable influence on the phenotype of terminally differentiated chondrocytes via physical cues. The Yes-associated protein (YAP) transcription co-activator is recognized as a key mediator that may be involved in the nuclear transduction of physical cues controlling cellular behavior and function. However, whether substrate elasticity in the regulation of the chondrocyte phenotype is associated with YAP remains unclear.
View Article and Find Full Text PDFMechanical cues exert considerable influence on the fates of stem cells and terminally differentiated chondrocytes. The elucidation of the interactions between cell fate and mechanical cues in nuclear mechanotransduction will provide new clues to modulate tissue homeostasis and regeneration. In this study, we used an integrated microfluidic perfusion device to simultaneously generate multiple-parameter fluid shear stresses to investigate the role of fluid flow stimuli in the regulation of Yes-associated protein (YAP) expression and the fates of mesenchymal stem cells (MSCs) and primary chondrocytes.
View Article and Find Full Text PDFThe proliferation of neonatal Schwann cells (SCs) in response to mitogenic agents has been well analyzed in vitro (mono-layer-culture method, 2D environment), but not in vivo (3D environment). To assess the mitogenic effect of platelet-derived growth factors-BB (PDGF-BB), Fibroblast Growth Factors-base (bFGF), and their combinations for SCs in collagen gel (three-dimensional, 3D environment), we have developed an integrated microfluidic device on which can reproducibly measure the proliferation from small number of cells (1-100). The rat SCs were cultured for 4 week at the different concentrations of growth factors generated by concentration gradient generator.
View Article and Find Full Text PDFThe effect of indigenous arbuscular mycorrhizal (AM) fungi on lead (Pb) and cadmium (Cd) uptake by the hyperaccumulator plant Viola baoshanensis was studied in greenhouse pot experiments. Seedlings of V. baoshanensis inoculated without or with indigenous AM fungi were grown in paddy soil with the addition of Pb at 0, 500, 1000 and 1500 mg kg(-1), or of Cd at 0, 50,100, 200 mg kg(-1), or in mine soil with the addition of phosphorus at 0, 50, 250, 500 mg kg(-1).
View Article and Find Full Text PDFA loamy soil contaminated with (137)CsCl 40 years ago was investigated by a sequential extraction technique to determine the effect of ageing on chemical availability of (137)Cs. The soil samples were sequentially extracted with H(2)O, NH(4)Ac, NH(2)OH x HCl, H(2)O(2), and HNO(3). Extractability of (137)Cs decreased in the order: HNO(3) > Residual > H(2)O(2) > NH(4)Ac > NH(2)OH x HCl > H(2)O.
View Article and Find Full Text PDFSci Total Environ
February 2005