Development of a rabbit corneal equivalent using an acellular corneal matrix of a porcine substrate

Purpose: The tissue equivalent that mimics the structure and function of normal tissue is a major bioengineering challenge. Tissue engineered replacement of diseased or damaged tissue has become a reality for some types of tissue such as skin and cartilage. The tissue engineered corneal epithelium, stroma, and endothelium scaffold are promising concepts in overcoming the current limitations of a cornea replacement with an allograft. Methods: The acellular corneal matrix from porcine (ACMP) was examined as a potential corneal cell sheet frame. The physical and mechanical properties of strength, expansion, transparency, and water content of the ACMP were measured. The major antigens of the cell components were completely removed with series of extraction methods, the major antigens of the cell components were identified by hematoxylin and eosin (HE), immunofluorescence staining, and scanning electron microscopy. The structural properties were investigated by HE stain and scanning electron microscopy. The three types of rabbit corneal cells were cultured in vitro, and characteristics were investigated by colony formation efficiency (CFE), BrdU staining, immunofluorescence staining, and western blot assay of keratin 3 (K3), vimentin, and aquaporin A. The biocompatibility of the ACMP was investigated for one month using rabbit corneal stroma and three types of cultured corneal cells both in vivo and in vitro. The three types of cultured rabbit corneal cells were seeded onto ACMP of each side at a cell density of 5.0x10(3) cells/mm(2). Results: The optical and mechanical properties of the ACMP were similar to the normal porcine cornea. The collagen fiber interconnected to the network, formed regular collagen bundles of the ACMP, and was parallel to the corneal surface. The ACMP was transferred to the rabbit cornea stroma, which showed an intact epithelium and keratocytes in the implant region. There were no inflamed cells or new vessel invasion one month after transplantation. The three types of cultured rabbit corneal cells were positive for K3, vimentin, and aquaporin A. CFE and BrdU (5-bromo-2'-deoxyuridine) staining showed no statistical difference. The cultured rabbit corneal limbal epithelial cells, keratocyte cells, and endothelial cells formed a confluent cell sheet on the ACMP, which consisted of one to two cell layers. Immunofluorescence and scanning electron microscopy examination showed that the cells steadily adhered to the surface of the ACMP and maintained their conformation and special molecule expression such as K3, vimentin, and aquaporin A. Rabbit corneal epithelium-ACMP, keratocytes-ACMP, and endothelium-ACMP scaffold was built in vitro. Conclusions: The rabbit corneal scaffold was made by the ACMP as a frame with three types of allogeneic rabbit corneal cells. This is a new concept in treating injured corneas.Biochemistry & Molecular BiologyOphthalmologySCI(E)PubMed21ARTICLE253-552180-21891

Extraordinary focusing of sound above a soda can array without time reversal

Recently, Lemoult et al. [Phys. Rev. Lett. 107, 064301 (2011)] used time reversal to focus sound above an array of soda cans into a spot much smaller than the acoustic wavelength in air. In this study, we show that equally sharp focusing can be achieved without time reversal, by arranging transducers around a nearly circular array of soda cans. The size of the focal spot at the center of the array is made progressively smaller as the frequency approaches the Helmholtz resonance frequency of a can from below, and, near the resonance, becomes smaller than the size of a single can. We show that the locally resonant metamaterial formed by soda cans supports a guided wave at frequencies below the Helmholtz resonance frequency. The small focal spot results from a small wavelength of this guided wave near the resonance in combination with a near field effect making the acoustic field concentrate at the opening of a can. The focusing is achieved with propagating rather than evanescent waves. No sub-diffraction-limited focusing is observed if the diffraction limit is defined with respect to the wavelength of the guided mode in the metamaterial medium rather than the wavelength of the bulk wave in air

On-chip black hole: Hawking radiation and curved spacetime in a superconducting quantum circuit with tunable couplers

Hawking radiation is one of quantum features of a black hole, which can be understood as a quantum tunneling across the event horizon of the black hole, but it is quite difficult to directly observe the Hawking radiation of an astrophysical black hole. Remarkable experiments of analogue black holes on various platforms have been performed. However, Hawking radiation and its quantum nature such as entanglement have not been well tested due to the experimental challenges in accurately constructing curved spacetime and precisely measuring the thermal spectrum. Based on the recent architecture breakthrough of tunable couplers for superconducting processor, we realize experimentally an analogue black hole using our new developed chip with a chain of 10 superconducting transmon qubits with interactions mediated by 9 transmon-type tunable couplers. By developing efficient techniques to engineer the couplings between qubits via tuning couplers, we realize both the flat and curved spacetime backgrounds. The quantum walks of quasi-particle in the curved spacetime reflect the gravitational effect around the black hole, resulting in the behavior of Hawking radiation. By virtue of the state tomography measurement of all 7 qubits outside the analogue event horizon, we show that Hawking radiation can be verified. In addition, an entangled pair is prepared inside the horizon and the dynamics of entanglement in the curved spacetime is directly measured. Our results would stimulate more interests to explore information paradox, entropy and other related features of black holes using programmable superconducting processor with tunable couplers.Comment: modified manuscripts, 7 pages, 4 figures (main text) + 12 pages (supplementary information

Parallel momentum distribution of the 28^{28}Si fragments from 29^{29}P

Distribution of the parallel momentum of $^{28}$Si fragments from the breakup of 30.7 MeV/nucleon $^{29}$P has been measured on C targets. The distribution has the FWHM with the value of 110.5 $\pm$ 23.5 MeV/c which is consistent quantitatively with Galuber model calculation assuming by a valence proton in $^{29}$P. The density distribution is also predicted by Skyrme-Hartree-Fock calculation. Results show that there might exist the proton-skin structure in $^{29}$P.Comment: 4 pages, 4 figure

The Combination of RAD001 and NVP-BEZ235 Exerts Synergistic Anticancer Activity against Non-Small Cell Lung Cancer In Vitro and In Vivo

The phosphoinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) signaling axis has emerged as a novel target for cancer therapy. Agents that inhibit PI3K, mTOR or both are currently under development. The mTOR allosteric inhibitor, RAD001, and the PI3K/mTOR dual kinase inhibitor, BEZ235, are examples of these agents. We were interested in developing strategies to enhance mTOR-targeted caner therapy. In this study, we found that BEZ235 alone effectively inhibited the growth of rapamycin-resistant cancer cells. Interestingly, the combination of sub-optimal concentrations of RAD001 and BEZ235 exerted synergistic inhibition of the growth of human lung cancer cells along with induction of apoptosis and G1 arrest. Furthermore, the combination was also more effective than either agent alone in inhibiting the growth of lung cancer xenografts in mice. The combination showed enhanced effects on inhibiting mTOR signaling and reducing the expression of c-Myc and cyclin D1. Taken together, our results suggest that the combination of RAD001 and BEZ235 is a novel strategy for cancer therapy

Common Features in Electronic Structure of the Fe-Based Layered Superconductors from Photoemission Spectroscopy

High resolution photoemission measurements have been carried out on non-superconducting LaOFeAs parent compound and various superconducting R(O1-xFx)FeAs (R=La, Ce and Pr) compounds. We found that the parent LaOFeAs compound shows a metallic character. Through extensive measurements, we have identified several common features in the electronic structure of these Fe-based compounds: (1). 0.2 eV feature in the valence band; (2). A universal 13~16 meV feature; (3). A clear Fermi cutoff showing zero leading-edge shift in the superconducting state;(4). Lack of superconducting coherence peak(s); (5). Near EF spectral weight suppression with decreasing temperature. These universal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials.Comment: 5 pages,4 figure