846 research outputs found

    Possibility of Macroscopic resonant Tunneling near the Superconductor- Insulator Transition in YBaCuO Thin Films

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    Experimental results of I-V characteristics near the superconductor-insulator transition observed for disorder-tuned YBaCuO thinfilms are presented. The I-V characteristics exibit new quasiperiodic structures as a function of the current. The current interval, the number of the dI/dV peaks, and the magnetic field dependence of the peaks are consistent with the theoretical predictions of the resonant tunneling of a phase particle ina tilted-cosine potential for asingle Josephson junction with small capacitance.Comment: 7 pages, 4 figures, in press (Europhys. Lett.

    A New Endoscopic Technique for Examination of Esophageal Stenosis: The Funnel-shaped Transparent Cap Technique

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    We have devised a funnel-shaped transparent cap for the endoscopic diagnosis and treatment of stenosis in the digestive tract. This funnel-shaped cap is made of highly transparent methacrylic resin. A 73-year-old woman with reflux esophagitis (categorized as grade D by the Los Angeles Classification) visited our hospital with the chief complaint of dysphagia. She was examined using an endoscope equipped with a transparent vinyl chloride hood at its tip. Many pieces of food were found to be trapped in the esophagus. These were removed using tripod forceps or aspirated into the hood. The internal diameter of the stenotic segment was as small as 1 or 2 mm, and it was difficult to advance the endoscope past the stenosis. The endoscope was withdrawn, and the attached hood was removed and replaced with a transparent cap. This provided clear visualization of the mucosal surface of the stenotic segment, which could not be examined using any conventional device, permitting the stenosis to be relieved

    Color Changes in Electronic Endoscopic Images Caused by Image Compression

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    In recent years, recording of color still images into magneto–optical video disks has been increasingly used as a method for recording electronic endoscopic images. In this case, image compression is often used to reduce the volume and cost of recording media and also to minimize the time required for image recording and playback. With this in mind, we recorded 8 images into a magneto-optical video disk in 4 image compression modes (no compression, weak compression, moderate compression, and strong compression) using the Joint Photographic Image Coding Experts Group (JPEG) system, which is a widely used and representative method for compressing color still images, in order to determine the relationship between the degree of image compression and the color information in electronic endoscopic images. The acquired images were transferred to an image processor using an offline system. A total of 10 regions of interest (ROls) were selected, and red (R), green (G), and blue (B) images were obtained using different compression modes. From histograms generated for these images, mean densities of R, G, and B in each ROI were measured and analyzed. The results revealed that color changes were greater for B, which had the lowest density, than for R or G as the degree of compression was increased

    SHG microscopic observations of polar state in Li-doped KTaO3 under electric field

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    Incipient ferroelectric KTaO3 with off-center Li impurity of the critical concentration of 2.8 mol% was investigated in order to clarify the dipole glass state under electric field. Using optical second-harmonic generation (SHG) microscope, we observed a marked history dependence of SHG intensity through zero-field cooling (ZFC), zero-field heating (ZFH), field heating after ZFC (FH/ZFC) and FH after field cooling (FH/FC). These show different paths with respect to temperature: In the ZFC/ZFH process, weak SHG was observed at low temperature, while in the FH/ZFC process, relatively high SHG appears in a limited temperature range below TF depending on the field strength, and in the FC and FH/FC processes, the SHG exhibits ferroelectric-like temperature dependence: it appears at the freezing temperature of 50K, increases with decreasing temperature and has a tendency of saturation. These experimental results strongly suggest that dipole glass state or polar nano-clusters which gradually freezes with decreasing temperature is transformed into semi-macroscopic polar state under the electric field. However at sufficiently low temperature, the freezing is so strong that the electric field cannot enlarge the polar clusters. These experimental results show that the polar nano-cluster model similar to relaxors would be more relevant in KTaO3 doped with the critical concentration of Li. Further experiments on the anisotropy of SHG determine that the average symmetry of the field-induced polar phase is tetragonal 4mm or 4, which is also confirmed by the X-ray diffraction measurement.Comment: 26 pages, 8 figures, 1 tabl

    The shape parameter of liposomes and DNA-lipid complexes determined by viscometry utilizing small sample volumes

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    A minicapillary viscometer utilizing \u3c0.5 ml of sample at a volume fraction of \u3c0.1% is described. The calculated a/b of DPPC/DPPG multilamellar liposome was 1.14 as prolate ellipsoids and a/b of dioleoylpropyltrimethyl ammonium methylsulfate-DNA complex at a charge ratio of 4:1 (+/-) was 3.7 as prolate ellipsoids or 4.9 as oblate ellipsoids. The deviation of shape from perfect sphere is thus expressed quantitatively in more than two significant figures. In these measurement, the necessary amount of DNA is \u3c0.5 mg

    An Inner Centromere Protein that Stimulates the Microtubule Depolymerizing Activity of a KinI Kinesin

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    AbstractMitosis requires precise control of microtubule dynamics. The KinI kinesin MCAK, a microtubule depolymerase, is critical for this regulation. In a screen to discover previously uncharacterized microtubule-associated proteins, we identified ICIS, a protein that stimulates MCAK activity in vitro. Consistent with this biochemical property, blocking ICIS function in Xenopus extracts with antibodies caused excessive microtubule growth and inhibited spindle formation. Prior to anaphase, ICIS localized in an MCAK-dependent manner to inner centromeres, the chromosomal region located in between sister kinetochores. From Xenopus extracts, ICIS coimmunoprecipitated MCAK and the inner centromere proteins INCENP and Aurora B, which are thought to promote chromosome biorientation. By immunoelectron microscopy, we found that ICIS is present on the surface of inner centromeres, placing it in an ideal location to depolymerize microtubules associated laterally with inner centromeres. At inner centromeres, MCAK-ICIS may destabilize these microtubules and provide a mechanism that prevents kinetochore-microtubule attachment errors

    Lung adenocarcinoma with giant cyst formation showing a variety of histologic patterns: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Lung cancer with large cyst formation is relatively rare. This is a case report of a patient with lung cystic adenocarcinoma with multiple histologic patterns. This type of lung adenocarcinoma is believed to be the first reported case in English language medical literature.</p> <p>Case presentation</p> <p>A 60-year-old Japanese woman was admitted to hospital complaining of dyspnea and died of respiratory failure. She had been suffering from lung cancer with pleural effusion for five years. Autopsy analysis revealed lung adenocarcinoma with large cyst formation showing a variety of histologic patterns.</p> <p>Conclusions</p> <p>Autopsy analysis of this atypical case of lung cancer may provide insight and lead to a better understanding of the heterogeneity and clonal expansion of lung adenocarcinoma.</p
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