Experimental investigation of pulsed entangled photons and photonic quantum channels

The development of key devices and systems in quantum information technology, such as entangled particle sources, quantum gates and quantum cryptographic systems, requires a reliable and well-established method for characterizing how well the devices or systems work. We report our recent work on experimental characterization of pulsed entangled photonic states and photonic quantum channels, using the methods of state and process tomography. By using state tomography, we could reliably evaluate the states generated from a two-photon source under development and develop a highly entangled pulsed photon source. We are also devoted to characterization of single-qubit and two-qubit photonic quantum channels. Characterization of typical single-qubit decoherence channels has been demonstrated using process tomography. Characterization of two-qubit channels, such as classically correlated channels and quantum mechanically correlated channels is under investigation. These characterization techniques for quantum states and quantum processes will be useful for developing photonic quantum devices and for improving their performances.Comment: 12 pages, 8 figures, in Quantum Optics in Computing and Communications, Songhao Liu, Guangcan Guo, Hoi-Kwong Lo, Nobuyuki Imoto, Eds., Proceedings of SPIE Vol. 4917, pp.13-24 (2002

INFLUENCE OF LATERAL TRUNK TILT ON THROWING ARM KINETICS DURING BASEBALL PITCHING

The purpose of this study was to investigate the relationship between lateral trunk tilt angle and several injury-related kinetic parameters during pitching. Based on kinematic data of 12 overhand and three-quarter-hand pitchers, several pitching motions with different lateral trunk tilt angles from the original were simulated. Joint kinetics among the simulated motions was compared. As a result, elbow medial force and elbow varus torque were generally increased as the lateral trunk tilt increased, that is the greater contra-lateral side-bending to the throwing arm side. On the other hand, the shoulder shear force was decreased as the lateral trunk tilt increased. Data from the study demonstrated that the shoulder proximal force was irrelevant to the trunk tilt angle

プラシノ藻類Tetraselmis tetratheleにおける水銀処理による酸化ストレスについて

Mercury-induced oxidative stress was observed in the cells of marine phytoplankton Tetraselmis tetrathele (Prasinophyceae) using the fluorescent probes 2' 7-dichlorofluorescindiacetate (DCFH-DA) and fluorescein diacetate (FDA). When the cells were exposed to 1μM of HgCl2， the fluorescence intensity of 2' 7' -dichlorofluorescin (DCF) was three times higher than that of the control level 60 min after the treatment， indicating H202 accumulation，and it gradually decreased. Moreover，exposure to 0.3μM of HgCl2 caused an increase in fluorescence 6h after the treatment. However，exposure to HgCl2 at concentrations of 3.0μM or greater did not cause an increase in fluorescence. It is thought that H202 was also generated at these concentrations，but could not be detected due to inactivation of the cellular esterase necessary to convert DCFH-DA to DCFH，and/or leakage from the cells due to membrane damage caused by HgCl2. The maximum level of fluorescence was approximately two times higher under light conditions than under dark conditions， suggesting that H202 was derived partly from photosynthesis. These results indicate that accumulation of H202 is involved inconsequence of the toxicity of mercury

The Bootstrap Dual Polarimetric Spectral Density Estimator

Weather radar moments and polarimetric variables provide useful information about the characteristics and motion of hydrometeors. However, the bulk information may be masked when the meteorological signal of interest is contaminated by clutter. The dual-polarimetric spectral densities (DPSD) may unveil additional information about the polarimetric characteristics of groups of scatterers moving at different Doppler velocities in a given radar resolution volume. Previous DPSD estimation methods required averaging a large number of spectra (obtained from different range gates, radials, or scans), or averaging in frequency to get accurate estimates; though by doing so, the resolution is degraded, and important features of the meteorological phenomenon may be masked, potentially affecting the ability to perform a good spectral analysis. In an attempt to overcome these limitations, the Bootstrap DPSD estimator is developed, which allows the estimation of DPSDs from a single dwell, with minimal resolution loss. Briefly, the estimator pre-processes the weather radar I/Q time-series signals and generates I/Q pseudo-realizations through bootstrap resampling, which are then used to compute PSD estimates that are averaged to obtain the DPSD estimate. Then, a post-processing stage applies a bias correction to the estimates. The Bootstrap DPSD estimator's performance is compared to that of conventional methods for single-dwell as well as for multiple-dwell estimates. Additionally, the performance and limitations of the Bootstrap and conventional DPSD estimators are assessed when identifying signals of different polarimetric signatures of scatterers moving at different radial velocities in the radar volume. The advantages of the Bootstrap DPSD estimator as a tool for polarimetric spectral analysis is demonstrated with a few examples of polarimetric spectral signatures in data from tornado cases, and from a physically-based simulator. It is expected that, with the Bootstrap DPSD and polarimetric spectral analysis, it will be possible to better understand tornado dynamics and their connection to weather radar measurements, as well as to elucidate important scientific questions that motivated this work

Determination of ADAMTS13 and Its Clinical Significance for ADAMTS13 Supplementation Therapy to Improve the Survival of Patients with Decompensated Liver Cirrhosis

The liver plays a central role in hemostasis by synthesizing clotting factors, coagulation inhibitors, and fibrinolytic proteins. Liver cirrhosis (LC), therefore, impacts on both primary and secondary hemostatic mechanisms. ADAMTS13 is a metalloproteinase, produced exclusively in hepatic stellate cells, and specifically cleaves unusually large von Willebrand factor multimers (UL-VWFM). Deficiency of ADAMTS13 results in accumulation of UL-VWFM, which induces platelet clumping or thrombi under high shear stress, followed by sinusoidal microcirculatory disturbances and subsequent progression of liver injuries, eventually leading to multiorgan failure. The marked imbalance between decreased ADAMTS13 activity (ADAMTS13 : AC) and increased production of UL-VWFM indicating a high-risk state of platelet microthrombi formation was closely related to functional liver capacity, hepatic encephalopathy, hepatorenal syndrome, and intractable ascites in advanced LC. Some end-stage LC patients with extremely low ADAMTS13 : AC and its IgG inhibitor may reflect conditions similar to thrombotic thrombocytopenic purpura (TTP) or may reflect “subclinical TTP.” Hence, cirrhotic patients with severe to moderate deficiency of ADAMTS13 : AC may be candidates for FFP infusion as a source of ADAMTS13 or for recombinant ADAMTS13 supplementation. Such treatments may improve the survival of patients with decompensated LC

Predicting Factors of Transmural Thermal Injury after Cryoballoon Pulmonary Vein Isolation

博士（医学）福島県立医科大

Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems

We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation