RESUMEN
We report two-photon interferences on a silica-on-silicon chip of Mach-Zehnder interferometer using telecommunication-band correlated photon pairs. The photon pairs were generated by spontaneous four-waving mixing process in a dispersion-shifted fiber. The integrated chip, which was fabricated by standard silica-on-silicon planar lightwave circuit technology, contained a Mach-Zehnder interferometer with a thermo-optic phase shifter. The insertion loss of the interferometer was less than 1 dB. We demonstrated two-photon interferences with both degenerate- and non-degenerate-frequency photon pairs on the Mach-Zehnder interferometer chip. A high fringe visibility was achieved in the interference with nondegenerate-frequency photons. Properties of quantum interference were demonstrated in the interference with degenerate-frequency photon pairs, which is an important way to manipulate the quantum state. These results show great potential of silica-on-silicon photonic chips in applications for the fiber-chip scheme in quantum networks.
RESUMEN
A two-dimensional photonic crystal coupled-cavity waveguide was designed and optimized by combining photonic crystal wavguide and cavity, transmission spectra of the waveguide were calculated by using FDTD method, and the transmittance and the group velocity were obtained through the transmission spectra. The calculation results show that a group velocity of upsilon(g) = c/130 and corresponding transmission of 20.1% can be obtained at wavelength 1.551 microm, and a group velocity of upsilon(g) = c/50 and transmission of 29.2% was obtained at wavelength 1.502 microm. The slow light in the waveguide was also analyzed by using photonic bandstructure calculated by plane-wave-expansion (PWE) method. The results of the photonic crystal waveguide with high transmission and low group velocity will have potential application in optical storage, optical delay and photonic integration.
RESUMEN
OBJECTIVE: The aim of this study was to determine whether autophagy of monocytes attenuates the vulnerability of atherosclerotic plaques. METHODS: The study group comprised 50 patients with stable angina pectoris (SAP), 50 patients with unstable angina pectoris (UAP), 40 patients with acute myocardial infarction (AMI), and 30 patients without coronary artery disease (control). Peripheral blood monocytes (PBMs) were isolated and the expression levels of the proteins beclin-1 and light chain 3 (LC3) (autophagy-specific proteins) in the PBMs were analyzed by western blot. A laser scanning confocal microscope was used to determine the levels of LC3 in the PBMs. RESULTS: Western blot analysis revealed that the expression of beclin-1 and LC3 was significantly lower in acute coronary syndrome patients than in the SAP and control groups (P<0.05). Among the acute coronary syndrome patients, the expression level of beclin-1 and LC3 in the AMI group was significantly decreased compared with that in the UAP group (P<0.05). However, there was no statistical difference between the SAP group and the control group. The results of immunofluorescence assays showed that the fluorescence intensity of LC3 in the PBMs of AMI patients was significantly lower than that in those of UAP patients (P<0.05), which was also significantly decreased compared with that in those of SAP patients and the control group (P<0.05). Expression levels of beclin 1 in the UAP and AMI groups had a negative linear correlation with C-reactive protein levels (r=-0.531, P<0.05; r=-0.589, P<0.05, respectively). CONCLUSION: Autophagy of PBMs is involved in the pathogenesis of plaque vulnerability and subsequent plaque rupture. Enhancing the autophagy of PBMs may be a new therapeutic target for stabilizing atherosclerotic plaques.