Optomechanically-induced nonreciprocal conversion between microwave and optical photons.

We theoretically propose a scheme of the nonreciprocal conversion device between photons of two arbitrary frequencies in a hybrid cavity optomechanical system, where two optical cavities and two microwave cavities are coupled to two different mechanical resonators via radiation pressure. Two mechanical resonators are coupled together via the Coulomb interaction. We study the nonreciprocal conversions between both the same and different types of frequency photons. The device is based on multichannel quantum interference to break the time-reversal symmetry. Our results show the perfect nonreciprocity conditions. By adjusting the Coulomb interaction and the phase differences, we find that the nonreciprocity can be modulated and even transformed into reciprocity. These results provide new insight into the design of nonreciprocal devices, including isolators, circulators, and routers in quantum information processing and quantum networks.

Whole-tumor perfusion CT using texture analysis in unresectable stage IIIA/B non-small cell lung cancer treated with recombinant human endostatin.

BACKGROUND: To observe the dynamic changes of blood perfusion with whole-tumor computed tomography (CT) perfusion imaging using texture analysis in patients with unresectable stage IIIA/B non-small cell lung cancer (NSCLC) treated with recombinant human endostatin (Endostar). METHODS: This phase II clinical trial recruited 11 patients diagnosed with stage IIIA/B NSCLC. Histological examination prior to treatment revealed squamous cell carcinoma in 4 cases and adenocarcinoma in 7 cases. All patients underwent contrast-enhanced perfusion CT at baseline and a second CT scan 1 week after treatment initiation with Endostar. CT perfusion images including blood flow (BF), blood volume (BV), and permeability (PMB) were imported into OmniKinetics software to quantitatively assess the texture features. Skewness, kurtosis, and entropy were calculated at baseline and after anti-angiogenic therapy. Changes in tumor were analyzed using Wilcoxon signed-rank test. The association of parameters with survival was evaluated using Cox proportional hazards regression model. RESULTS: There were no statistical differences in the mean values of BF, BV, and PMB before and after treatment (P=0.594, 0.477 and 0.328, respectively). The skewness on BF images demonstrated significant differences at baseline and after treatment (0.6±2.7 vs. 1.0±2.6, P=0.010), while skewness of BV and PMB showed no significant variation (P=0.477 and 0.213, respectively). The kurtosis and entropy for BF, BV and PMB showed no significant differences (all P>0.05). In adenocarcinoma, the mean BF showed no significant differences at baseline and after treatment (76.5±25.7 vs. 101.2±46.4, P=0.398), while skewness for BF was significantly higher after treatment than at baseline (-0.19±3.3 vs. 0.59±3.2, P=0.028). No significant associations were found between perfusion CT imaging parameters and progression-free survival. CONCLUSIONS: These results suggested that blood perfusion showed improvement with whole-tumor perfusion CT using texture analysis in patients with stage IIIA/B NSCLC treated by Endostar.

Experimental proposal for performing nonlocal measurement of a product observable.

Due to the restrictions on quantum measurement imposed by relativistic causality, it is not easy to perform a nonlocal measurement on spacelike separated systems instantaneously. Here we design an experiment in an optical system to perform the nonlocal measurement of a product observable on a two-qubit system, where a maximally-entangled two-qubit state, acting as an ancillary meter, and three identical Kerr media are used to couple the system under consideration and the target meter. It is shown that the nonlocal measurement of the product observable, σzA⊗σzB, which has two degenerate eigenvalues, could be implemented in a deterministic way without violating relativistic causality.

Tracing the trajectory of photons through Fourier spectrum.

By slightly vibrating the mirrors in an interferometer at different frequencies, the photons' trajectory information is stored in the light beam. To read out this information, we record the centroid location of the intensity distribution of output beam and Fourier analyze its time evolution. It is shown that every vibrating mirror contributes a peak in the Fourier spectrum. In other words, we can reveal the trajectory of the photons by figuring out the vibrating mirrors which ever interact with the light beam based on the Fourier spectrum. This techniques is not limited by the vibration amplitude of the mirrors.

[Detection and diagnostic value of serum carcinoembryonic antigen and cytokeratin 19 fragment in lung cancer patients].

OBJECTIVE: To explore the diagnostic value of carcinoembryonic antigen (CEA) and cytokeratin-19-fragment (CYFRA21-1) in lung cancer patients. METHODS: The levels of serum CEA and CYFRA21-1 were measured in 102 patients with lung cancer, 45 patients with benign lung disease and 36 health controls by electrochemiluminescence. RESULTS: The level of serum CEA and positive rate [(25.77 ± 15.34) ng/ml, 47.1%] were significantly higher in the lung cancer group than that in the benign lung disease group [(4.67 ± 2.21) ml, 7.7%; P < 0.05] and controls [(3.98 ± 3.00) ng/ml, 3.8%; P < 0.05], The level of serum CYFRA21-1 and positive rate [(14.08 ± 8.34) ng/ml, 62.7%] were also significantly higher in the lung cancer group than that in the benign lung disease group [(3.27 ± 2.87) ml, 7.7%; P < 0.05] and controls [(2.69 ± 2.02 ng/ml, 3.8%; P < 0.05]. The difference of level of CEA and CYFRA21-1 between the benign lung disease group and controls was statistically not significant (P > 0.05). Both tumor markers were increased to a different degree in the lung cancer patients at various TNM stages [(CEA: stage II (17.78 ± 8.71) ng/ml, stage III (25.84 ± 7.34) ng/ml, stage IV (34.85 ± 6.99) ng/ml; and CYFRA21-1: stage II (10.05 ± 6.76) ng/ml, stage III (15.93 ± 6.66) ng/ml, stage IV (22.78 ± 4.12) ng/ml]. Combined use of both makers showed a significant higher sensitivity (77.5% vs. 47.1%, 62.8%), but reduced specificity (86.8% vs. 94.0%, 95.6%), and not significantly changed accuracy (83.5% vs. 77.1%, 83.8%) in the diagnosis of lung cancer. CONCLUSIONS: CEA and CYFRA21-1 employed separately are helpful in the diagnosis of lung cancer. Combined detection of these two tumor markers can improve the positivity for diagnosis of lung cancer.

Omnidirectional bandgaps in Fibonacci quasicrystals containing single-negative materials.

The band structure and bandgaps of one-dimensional Fibonacci quasicrystals composed of epsilon-negative materials and mu-negative materials are studied. We show that an omnidirectional bandgap (OBG) exists in the Fibonacci structure. In contrast to the Bragg gaps, such an OBG is insensitive to the incident angle and the polarization of light, and the width and location of the OBG cease to change with increasing Fibonacci order, but vary with the thickness ratio of both components, and the OBG closes when the thickness ratio is equal to the golden ratio. Moreover, the general formulations of the higher and lower band edges of the OBG are obtained by the effective medium theory. These results could lead to further applications of Fibonacci structures.