Exact solutions and symmetry analysis for the limiting probability distribution of quantum walks

In the literature, there are numerous studies of one-dimensional discrete-time quantum walks (DTQWs) using a moving shift operator. However, there is no exact solution for the limiting probability distributions of DTQWs on cycles using a general coin or swapping shift operator. In this paper, we derive exact solutions for the limiting probability distribution of quantum walks using a general coin and swapping shift operator on cycles for the first time. Based on the exact solutions, we show how to generate symmetric quantum walks and determine the condition under which a symmetric quantum walk appears. Our results suggest that choosing various coin and initial state parameters can achieve a symmetric quantum walk. By defining a quantity to measure the variation of symmetry, deviation and mixing time of symmetric quantum walks are also investigated.     

Effect of temporal resolution on the estimation of left ventricular function by cardiac MR imaging

The aim of this study was to investigate the effect of temporal resolution on the estimation of left ventricular (LV) function by cardiac magnetic resonance (MR) imaging using a steady-state free precession (SSFP) sequence. Left ventricular function was assessed by cine MR imaging using a segmented SSFP sequence in 10 healthy volunteers. Views per segment (VPS) were set at 8 and 20, resulting in high and low true temporal resolution, respectively. Irrespective of VPS, images were reconstructed at 40 cardiac phases, providing high apparent temporal resolution. Data were analyzed using 40, 20 and 10 phases to simulate different apparent temporal resolutions. Increasing the cardiac phases used for analysis slightly decreased mean end-systolic volume (ESV) and slightly increased mean ejection fraction (EF). No substantial difference in estimates of end-diastolic volume (EDV) was found between VPSs of 8 and 20. Imaging with a VPS of 20 yielded a larger ESV and smaller EF than imaging with a VPS of 8 when 40 phases were used. In conclusion, low true temporal resolution causes overestimation of ESV and underestimation of EF. Improvement of apparent temporal resolution mildly reduces but does not eliminate the errors caused by low true temporal resolution.     

Detection and grading for esophageal varices in patients with chronic liver damage: comparison of gadolinium-enhanced and unenhanced steady-state coherent MR images

The purpose of this study was to compare observer interpreted steady-state coherent coronal images and gadolinium-enhanced axial images in terms of the detection and grading of esophageal varices. Magnetic resonance imaging (MRI) and gastrointestinal endoscopy were performed within 2 weeks in 90 patients with chronic liver damage, including 55 with untreated esophageal varices, for periodic screening purposes. Two blinded readers retrospectively reviewed T1- and T2-weighted images with gadolinium-enhanced (gadolinium image set) and steady-state coherent (coherent image set) images. Sensitivity for the detection of esophageal varices was higher (P<.001) in the gadolinium image set (76%) than in the coherent image set (35%); on the other hand, specificity was higher (P<.001) in the coherent image set (91%) than in the gadolinium image set (66%). Furthermore, area under the ROC curve was higher for the gadolinium image set (Az=0.823) than the coherent image set (Az=0.761) (P=.48). Moderate and weak positive correlations with endoscopic grades were found for the gadolinium image (r=0.48, P<.01) and coherent image sets (r=0.34, P=.018). The addition of steady-state coherent imaging to the current routine liver imaging protocol did not improve the detection or grading of esophageal varices, whereas gadolinium-enhanced imaging was found to be potentially valuable. Nevertheless, endoscopy was confirmed to be mandatory in patients with esophageal varices suspected by MRI of the liver.     

Effect of cation doping on ionic and electronic properties for lanthanum silicate-based solid electrolytes

Electronic as well as ionic conducting properties for oxyapatite-type solid electrolytes based on lanthanum silicate, La_9.333 + xSi₆O_26 + 1.5x (LSO) were investigated in the oxygen-excess region (x > ca. 0.3). We have found that the oxygen excess-type LSO (OE-LSO), namely La₁₀Si₆O₂₇ on weighted basis, exhibited high conductivity, and substitution of the Si-site of LSO with some dopants (Mⁿ⁺) had a positive effect toward the conducting property. Furthermore, it was also found that addition of a very small amount of iron ions into the M-doped OE-LSO, La₁₀(Si_6-yMⁿ⁺_y)O_27-(2-0.5n)y, improved its conductivity. On the other hand, replacement of the La-site with various ions for La₁₀(Si_6-yMⁿ⁺_y)O_27-(2-0.5n)y did little to improve conductivity. The electronic transport numbers for Al-doped OE-LSO with Fe-addition, (1-α){La₁₀(Si_5.8Al_0.2)O_26.9}-α(FeO_γ), evaluated with the Hebb-Wagner polarization method were very low: i.e., 1.1 × 10^− 3 and 2.9 × 10^− 3 under P(O₂) = 1.1 × 10⁴ Pa at 1073 K for α = 0.00 and 0.005, respectively. Conductivity for each sample was unchanged under humidified atmosphere at 1073 K sustained for over 50 h, revealing that both compositions were chemically stable. It was concluded that 0.995{La₁₀(Si_5.8Al_0.2)O_26.9}-0.005(FeO_γ) is suitable for the fuel cell electrolytes because of its high and almost pure ionic conductivity, and its good chemical stability under humidified as well as reducing conditions.     

The effect of artifacts on dependence measurement in fMRI

The study of effective connectivity by means of neuroimaging depends on the measurement of similarity between activity patterns at different locations in the brain, without necessarily presupposing a particular model for this dependence. When these interactions are measured using functional magnetic resonance imaging (fMRI) techniques, however, imaging and physiological artifacts create patterns of dependence that may be unrelated to cortical activity. We demonstrate some of these effects through the measurement of short-range dependencies present in fMRI scans of the primary visual cortex (V1) in the anaesthetized macaque monkey. High-field (4.7 T) fMRI scans were conducted to measure responses based on the blood oxygen level-dependent contrast mechanism, during periods of no sensory stimulation and of visual stimulation with rotating polar-transformed checkerboard gratings. Dependence between the haemodynamic activity at different spatial locations (i.e., different voxels) was measured using correlation, mutual information and functional covariance. Particular attention was paid to understanding the sources of spurious dependence that may be observed during such investigations. Two main effects were detected: (a) short-range correlations introduced by the process of image reconstruction and (b) perturbations in the haemodynamic response caused by breathing. The image reconstruction artifacts were shown to create an artificially high short-range dependence in the readout direction of the scan, and the breathing artifacts caused enhanced short-range dependence in both the readout and phase-encode directions. Additional dependence in the phase-encode direction due to image-ghosting is also possible but will not be discussed in this report, as it can be alleviated by fine adjustment of preemphasis (elimination of eddy currents). A technique is described for removing breathing artifacts, and the effect of breathing on the apparent dependence between voxels is illustrated. The correlation of haemodynamic activity with the stimulus was found to be affected by breathing, although this effect can be neutralised by averaging the haemodynamic responses over many repetitions of the stimulus. Nonetheless, patterns of dependent activity between voxels may be lost in this averaging process, which makes the removal of breathing artifacts necessary if statistical dependence and the study of effective connectivity is the primary aim of an investigation.     

Birth–death process of local structures in defect turbulence described by the one-dimensional complex Ginzburg–Landau equation

Defect turbulence described by the one-dimensional complex Ginzburg–Landau equation is investigated and analyzed via a birth–death process of the local structures composed of defects, holes, and modulated amplitude waves (MAWs). All the number statistics of each local structure, in its stationary state, are subjected to Poisson statistics. In addition, the probability density functions of interarrival times of defects, lifetimes of holes, and MAWs show the existence of long-memory and some characteristic time scales caused by zigzag motions of oscillating traveling holes. The corresponding stochastic process for these observations is fully described by a non-Markovian master equation.     

Prototype Demonstration of Discrete Correlation Processor-2 Based on High-Speed Optical Image Steering for Large-Fan-Out Reconfigurable Optical Interconnections

We present a discrete correlation processor-2 (DCP-2), which is an optical processor with reconfigurability of interconnection patterns for large-fan-out optical interconnection systems. To our knowledge, there is no reconfigurable optical processor satisfying the requirements for large fan-outs such as high-speed reconfiguration of interconnection pattern, high optical efficiency, and high contrast ratio, because existing spatial light modulators (SLM#x0027;s) lack at least one of these features. The DCP-2 architecture fulfills the requirements by using a hybrid configuration composed of a high-speed image steerer and a spatial light modulator, which work in a complementary manner to shorten the setup time of the SLM. We constructed two kinds of prototype demonstrators based on this architecture. In the experiment, reconfiguration speed of the DCP-2 prototype with shift-invariant optical interconnections, in which a liquid crystal SLM cooperated with a two-dimensional acousto-optic beam deflector, was about 26,000 times faster than that of the standalone SLM at the cost of 50#x0025; energy loss by the deflector.     

Highly biocompatible, hollow coordination polymer nanoparticles as cisplatin carriers for efficient intracellular drug delivery

Highly biocompatible coordination polymer (Prussian Blue) nanoparticles (LC(50) > 1000 μg mL(-1)) with a hollow interior and a microporous framework (denoted as HPB) are utilized as an anticancer drug (i.e. cisplatin) capsule for chemotherapy of bladder cancer T24 cells.     

Porphyrin nanochannels reinforced by hydrogen bonding

Carboxyl groups were introduced at the peripheral positions of dodecaphenylporphyrin to link nanochannel structures with intermolecular hydrogen bonds to make the supramolecular structures robust.