ABSTRACT
A single metasurface-based device possessing multiple functionalities is highly desirable for terahertz technology system. In this paper, we design a reflective metasurface to generate switchable vortex beams carrying orbital angular momentum (OAM), focusing beams, focusing beams with arbitrary positions, and vortex beams with arbitrary topological charges in the terahertz region. By combining the spin decoupling principle and the phase addition theorem, the superposition states of OAM and focusing beams with arbitrary positions can be independent manipulated under right-handed and left-handed circularly polarized (LCP/RCP) waves illumination. Such a diversified functionalities device provides a promising application in the field of terahertz communication and terahertz super-resolution imaging.
ABSTRACT
This paper proposes a novel metasurface that can simultaneously generate orbital angular momentum (OAM) beams with pre-designed different reflection directions, multi-beam and multi-mode under x-(y-) polarized terahertz wave incidence. The configuration of unit cell is made up of a hollow cross of Jesus structure as top layer, a PTFE substrate layer and a gold metal bottom plate. Theory of phase gradient distribution is derived and used to design multifunctional OAM metasurface. The proposed metasurface generates two OAM beams with OAM mode l = 1 and four OAM beams with l = -1 at frequency of 1 THz, respectively. Similarly, at frequency of 1.3 THz, the designed metasurface produces two OAM beams with l = -2 and an OAM beam with l = 2 for x-(y-) polarized wave incidence, respectively. Since each OAM mode can be used as an independent digital information coding channel, the designed multifunctional OAM metasurface has a wide application prospect in future terahertz communication.
ABSTRACT
AIM: To explore the effects of conditioned media on the proliferation of corneal endothelial cells (CECs) and to compare the efficiency of different conditioned media (CM). METHODS: Rat CECs, corneal stromal cells (CSCs), bone marrow-derived endothelial progenitor cells (BEPCs), and bone marrow-derived mesenchymal stem cells (BMSCs) were isolated and cultured in vitro. CM was collected from CSCs, BEPCs, and BMSCs. CECs were cultivated in different culture media. Cell morphology was recorded, and gene and protein expression were analyzed. RESULTS: After grown in CM for 5d, CECs in each experimental group remained polygonal, in a cobblestone-like monolayer arrangement. Immunocytofluorescence revealed positive expression of Na(+)/K(+)-ATP, aquaporin 1 (AQP1), and zonula occludens 1 (ZO-1). Based on quantitative polymerase chain reaction (qPCR) analysis, Na(+)/K(+)-ATP expression in CSC-CM was notably upregulated by 1.3-fold (±0.036) (P<0.05, n=3). The expression levels of ZO-1, neuron specific enolase (NSE), Vimentin, paired homebox 6 (PAX6), and procollagen type VIII (COL8A1) were notably upregulated in each experimental group. Each CM had a positive effect on CEC proliferation, and CSC-CM had the strongest effect on proliferation. CONCLUSION: CSC-CM, BEPC-CM, and BMSC-CM not only stimulated the proliferation of CECs, but also maintained the characteristic differentiated phenotypes necessary for endothelial functions. CSC-CM had the most notable effect on CEC proliferation.
ABSTRACT
Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have extensive self-renewal capacity and the potential to differentiate into all tissue-specific cell lineages, including corneal endothelial cells (CECs). They are a promising prospect for the future of regenerative medicine. The method of derivation of CECs from ESCs and iPSCs, however, remains to be elucidated. In this study, mouse ESCs and iPSCs were induced to differentiate into CECs using CEC embryonic development events as a guide. All-trans retinoic acid (RA) treatment during the embryoid body (EB) differentiation step was used to promote neural crest (NC) cell differentiation as first step and was followed by a second induction in CEC- or lens epithelial cell (LEC)-conditioned medium (CM) to ultimately generate CEC-like cells. During the corresponding differentiation stages, NC developmental markers and CEC differentiation markers were detected at the protein level using immunocytochemistry (ICC) and at the mRNA level by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). During the first stage, the data indicated that 4 days of treatment with 1 µM RA starting on day 4 of EB formation favored NC cell differentiation and that plating on gelatin-coated plates led to cell migration out of the EBs. The second-stage differentiation results showed that the CM, particularly the LEC-CM, enhanced the yield of polygonal cells with CEC-specific marker expression shown by ICC and RT-qPCR. This study demonstrates that mouse ESCs and iPSCs were induced and expressed CEC differentiation markers when subjected to a two-step inducement process, suggesting that they are a promising resource for corneal endothelium failure replacement therapy in the future.
