Time-reversed two-photon interferometry for phase super-resolution

We observed two-photon phase super-resolution in an unbalanced Michelson interferometer with classical Gaussian laser pulses. Our work is a time-reversed version of a two-photon interference experiment using an unbalanced Michelson interferometer. A measured interferogram exhibits two-photon phase super-resolution with a high visibility of 97.9% \pm 0.4%. Its coherence length is about 22 times longer than that of the input laser pulses. It is a classical analogue to the large difference between the one- and two-photon coherence lengths of entangled photon pairs.Comment: 6 pages, 4 figure

Observation of nonlinear variations in three-vertex geometric phase in two-photon polarization qutrit

We experimentally observed nonlinear variations in the three-vertex geometric phase in a two- photon polarization qutrit. The three-vertex geometric phase is defined by three quantum states, which generally forms a three-state (qutrit) system. By changing one of the three constituent states, we observed two rapid increases in the three-vertex geometric phase. The observed variations are inherent in a three-state system and cannot be observed in a two-state system. We used a time-reversed two-photon interferometer to measure the geometric phase with much more intense signals than those of a typical two-photon interferometer.Comment: 6 pages, 5 figure

Association Between Eosinophilia and Late-onset Circulatory Collapse in Preterm Infants: A case-Control Study

Late-onset circulatory collapse (LCC) in preterm infants is presumably caused by relative adrenal insufficiency. Because eosinophilia is known to be associated with adrenal insufficiency, we attempted to clarify the relation-ship between eosinophilia and LCC in preterm infants. We divided the cases of the infants (born at < 28 weeks’ gestation) admitted to our neonatal intensive care unit in 2008-2010 into 2 groups: those diagnosed with LCC that received glucocorticoids (LCC group), and those who did not receive glucocorticoids (control group). We compared eosinophil counts between the 2 groups and between before and after glucocorticoid treatment in the LCC group. A total of 28 infants were examined: LCC group (n = 12); control group (n = 16). The peak eosin-ophil counts of the LCC group were significantly higher than those of the control group (median: 1.392 × 109/L vs. 1.033 × 109/L, respectively; p = 0.02). Additionally, in the LCC group, the eosinophil counts declined significantly after glucocorticoid treatment (0.877 × 109/L vs. 0.271 × 109/L, p = 0.003). Eosinophil counts in the LCC group were significantly higher than in the control group and decreased rapidly after gluco-corticoid treatment. These results indicate that eosinophilia may be a factor associated with LCC caused by adrenal insufficiency

Two-photon interference of photon pairs created in photonic crystal fibers

We investigate a method to produce photon pairs by four-wave mixing in photonic crystal fibers (PCFs). By controlling the wavelength of the pump light, which determines the phase matching condition for four-wave mixing, we can obtain a broader spectrum of photon pairs than undesired Raman-scattered photons. We observe two-photon interference of photon pairs from a PCF with the help of an unbalanced Mach-Zehnder interferometer. Two-photon interference fringes with 83% visibility, which exceeds the classical limit of 50%, are obtained.Comment: 5 pages, 6 figures, to be published in JPS

Direct measurement of ultrafast temporal wavefunctions

The large capacity and robustness of information encoding in the temporal mode of photons is important in quantum information processing, in which characterizing temporal quantum states with high usability and time resolution is essential. We propose and demonstrate a direct measurement method of temporal complex wavefunctions for weak light at a single-photon level with subpicosecond time resolution. Our direct measurement is realized by ultrafast metrology of the interference between the light under test and self-generated monochromatic reference light; no external reference light or complicated post-processing algorithms are required. Hence, this method is versatile and potentially widely applicable for temporal state characterization.Comment: 10 pages, 7 figure

超常磁性体を用いたMRリンフォグラフィーによる口腔癌患者のセンチネルリンパ節同定

The purpose of this study was to examine the feasibility of interstitial MR lymphography using Superparamagnetic Iron Oxide (SPIO) to detect sentinel lymph nodes (SLNs) in head and neck cancer. For two patients with cT2N0 squamous cell carcinoma of the tongue, the submucosal injection of SPIO as well as sentinel lymph node navigation surgery (SLNNS) was performed before undergoing surgical treatment. SPIO was used for MR lymphography and Tc-99m phytate for SPECT. We compared the images by both modalities. Berlin blue stain was also performed postoperatively if SLNs had the uptake of SPIO. The lymph nodes with MR signal attenuation and those with hot spots were probed to be anatomically identical. All the lymph nodes detected as a SLN by a gamma-probe contained the blue granules from SPIO. These data suggest that SPIO can be a novel tracer for performing SLNNS and SLN biopsy in oral cancer patients with cN0 neck.博士（医学）・甲622号・平成26年3月17

Three-dimensional sodium chloride (NaCl) model for simulated mandibular reconstruction surgery : a new environmentally friendly material

Background : Mandibular reconstruction using a fibular graft is a difficult procedure that requires technical expertise to enable adequate occlusal function and restore an aesthetic appearance. Here we used three-dimensional (3D) sodium chloride (NaCl) models for simulated mandibular reconstruction surgery. This study aimed to reveal the accuracy of mandibular reconstruction with fibular grafts using this model. Methods : Mandibular reconstructions using 3D NaCl models were performed in 5 cases. The maxilla, mandible, and fibular models were developed using computed tomography (CT) data. We performed preoperative cutting and simulation surgery using this model. Angles between the body of the corpus and symphysis were measured from the axial view (n = 4). Angles between the ramus and the body of the corpus were measured from the lateral and axial views (n = 6). These angles were measured on simulated models and postoperative CT images were compared. Results : Differences between the angles measured on the simulated models and postoperative CT images were 0-5°(mean, 1.9°). Conclusions : We were able to reproduce the neomandibles with precise osteotomies using the 3D NaCl models. We believe that simulated mandibular reconstruction surgery using this model might help reduce the number of intraoperative neomandibular segment adjustments