110 research outputs found

    Enhanced Unified Theory with Forward-Speed Effect Taken into Account in the Inner Free-Surface Condition

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    The enhanced unified theory (EUT) has been used as a core theory in the integrated system developed at the Research Initiative on Oceangoing Ships (RIOS) of Osaka University for predicting the propulsion and seakeeping performance of a ship in actual seas. In this study, the EUT is modified by adopting partially the solution method in the rational strip theory of Ogilvie and Tuck as a particular solution in the inner problem, thereby a forward-speed effect in the convection term of the free-surface condition is incorporated in the inner solution. This forward-speed effect is analytically shown to contribute only to the cross-coupling radiation forces. Some other forward-speed and 3D effects important in a low-frequency range are also included in the homogeneous component of the inner solution through matching with the outer solution in a similar manner to the unified theory of Newman. Numerical computations are implemented for a slender modified Wigley model and the RIOS bulk carrier model. Good agreement is confirmed in a comparison with experimental data for the cross-coupling added mass and damping coefficients between heave and pitch and also for the resulting ship motions, particularly in heave near the resonant frequency. The added resistance around the motion-resonant wavelength is found to be improved but sensitive to a slight change in heave and pitch motions. Thus, it is stressed that accurate prediction of the ship motions and resultant Kochin function is critical for more accurate prediction of the added resistance in waves.Kashiwagi, Masashi. "Enhanced Unified Theory with Forward-Speed Effect Taken into Account in the Inner Free-Surface Condition." J Ship Res 66 (2022): 1–14. doi: https://doi.org/10.5957/JOSR.04200028

    Perioperative immune responses in cancer patients undergoing digestive surgeries

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    <p>Abstract</p> <p>Background</p> <p>Th1/Th2 cell balance is thought to be shifted toward a Th2-type immune response not only by malignancy but also by surgical stress. The aim of this study was to estimate perioperative immune responses with respect to the Th1/Th2 balance in patients with gastrointestinal cancer.</p> <p>Methods</p> <p>Ninety-four patients who underwent abdominal surgeries were divided into three groups: gastric resection (n = 40), colorectal resection (n = 34) and hepatic resection (n = 20). Twelve patients undergoing laparoscopic cholecystectomy and 20 healthy subjects were served as control groups. Intracellular cytokine staining in CD4+ T lymphocytes was identified to characterize Th1/Th2 balance. Th1/Th2 balance was evaluated before operation and until postoperative days (POD) 14.</p> <p>Results</p> <p>The preoperative Th1/Th2 ratio was significantly lower in patients with malignancy compared with control. The Th1/Th2 ratio of patients in all groups decreased significantly postoperatively. Th1/Th2 balance on POD 2 in patients with malignancy was significantly decreased compared to patients with laparoscopic cholecystectomy, but there were no significant differences among the four groups on POD 14.</p> <p>Conclusion</p> <p>Patients with malignancy showed an abnormal perioperative Th1/Th2 balance suggesting predominance of a type-2 immune response. Major abdominal surgeries induce a marked shift in Th1/Th2 balance toward Th2 in the early postoperative stage.</p

    Broadly Tunable Sub-terahertz Emission from Internal Branches of the Current-voltage Characteristics of Superconducting Bi2Sr2CaCu2O8+d Single Crystals

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    Continuous, coherent sub-terahertz radiation arises when a dc voltage is applied across a stack of the many intrinsic Josephson junctions in a Bi2Sr2CaCu2O8+d single crystal. The active junctions produce an equal number of I-V characteristic branches. Each branch radiates at a slightly tunable frequency obeying the ac Josephson relation. The overall output is broadly tunable and nearly independent of heating effects and internal cavity frequencies. Amplification by a surrounding external cavity to allow for the development of a useful high-power source is proposed.Comment: 4 pages, 4 figures, accepted for publication in PR

    Detection and management of cardiomyopathy in female dystrophinopathy carriers

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    Regular health checkups for mothers of patients with Duchenne muscular dystrophy have been performed at National Hospital Organization Tokushima Hospital since 1994. Among 43 mothers participated in this study, 28 dystrophinopathy carriers were identified. Skeletal and cardiac muscle functions of these subjects were examined. High serum creatine kinase was found in 23 subjects (82.1%). Obvious muscle weakness was present in 5 (17.8%) and had progressed from 1994 to 2015. Cardiomyopathy was observed in 15 subjects (60.0%), including dilated cardiomyopathy-like damage that was more common in the left ventricular (LV) posterior wall. Late gadolinium enhancement on cardiac MRI was found in 5 of 6 subjects, suggesting fibrotic cardiac muscle. In speckle tracking echocardiography performed seven years later, global longitudinal strain was decreased in these subjects, indicating LV myocardial contractile abnormality. These results suggest that female dystrophinopathy carriers should receive regular checkups for detection and treatment of cardiomyopathy, even if they have no cardiac symptoms

    Giant gastrointestinal stromal tumor, associated with esophageal hiatus hernia

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    An 85-year-old woman was admitted to our hospital because of vomiting. An upper gastrointestinal series what showed a large esophageal hiatus hernia, suggesting an association with extrinsic pressure in the middle portion of the stomach. An upper gastrointestinal endoscopic examination showed severe esophagitis and a prominent narrowing in the middle portion of the stomach, however, it showed normal gastric mucosa findings. CT and MRI revealed a large tumor extending from the region of the lower chest to the upper abdomen. From these findings, the tumor was diagnosed as gastrointestinal stromal tumor(GIST), which arose from the gastric wall and complicated with an esophageal hiatus hernia. We performed a laparotomy, however, the tumor showed severe invasion to the circumferential organs. Therefore, we abandoned the excision of the tumor. Histologically, the tumor was composed of spindle shaped cells with marked nuclear atypia and prominent mitosis. The tumor cells were strongly positive for CD34 and c-kit by immunohistochemical examination. From these findings, the tumor was definitely diagnosed as a malignant GIST. As palliative treatment, we implanted a self-expandable metallic stent in the narrow segment of the stomach. The patient could eat solid food and was discharged. In the treatment of esophageal hiatus hernia, the rare association of GIST should be considered

    Clinical implications of thymidylate synthetase, dihydropyrimidine dehydrogenase and orotate phosphoribosyl transferase activity levels in colorectal carcinoma following radical resection and administration of adjuvant 5-FU chemotherapy

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    <p>Abstract</p> <p>Bckground</p> <p>A number of studies have investigated whether the activity levels of enzymes involved in 5-fluorouracil (5-FU) metabolism are prognostic factors for survival in patients with colorectal carcinoma. Most reports have examined thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) in unresectable or metastatic cases, therefore it is unclear whether the activity of these enzymes is of prognostic value in colorectal cancer patients treated with radical resection and adjuvant chemotherapy with 5-FU.</p> <p>Methods</p> <p>This study examined fresh frozen specimens of colorectal carcinoma from 40 patients who had undergone curative operation and were orally administered adjuvant tegafur/uracil (UFT) chemotherapy. TS, DPD and orotate phosphoribosyl transferase (OPRT) activities were assayed in cancer tissue and adjacent normal tissue and their association with clinicopathological variables was investigated. In addition, the relationships between TS, DPD and OPRT activities and patient survival were examined to determine whether any of these enzymes could be useful prognostic factors.</p> <p>Results</p> <p>While there was no clear relationship between pathological findings and TS or DPD activity, OPRT activity was significantly lower in tumors with lymph node metastasis than in tumors lacking lymph node metastasis. Postoperative survival was significantly better in the groups with low TS activity and/or high OPRT activity.</p> <p>Conclusion</p> <p>TS and OPRT activity levels in tumor tissue may be important prognostic factors for survival in Dukes' B and C colorectal carcinoma with radical resection and adjuvant chemotherapy with UFT.</p

    非定常波形解析による波浪中抵抗増加に関する流体力学的研究 (非線形波動現象の数理とその応用)

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    It is known that the added resistance in waves can be computed from ship-generated unsteady waves through the unsteady wave-analysis method. In order to investigate the effects of nonlinear ship-generated unsteady waves and bluntness of the ship geometry on the added resistance, measurements of unsteady waves, wave-induced ship motions and added resistance are carried out using two different (blunt and slender) modified Wigley models. The ship-generated unsteady waves are also produced by the linear superposition using the waves measured for the diffraction and radiation problems and the complex amplitudes of ship motions measured for the motion-free problem in waves. Then a comparison is made among the values of the added resistance by the direct measurement using a dynamometer and by the wave-analysis method using the Fourier transform of measured and superposed waves. It is found that near the peak of the added resistance where ship motions become large, the degree of nonlinearity in the unsteady wave becomes prominent especially at the fore-front part of the wave. Thus the added resistance evaluated with measured waves at larger amplitude of incident wave becomes much smaller than the values by the direct measurement and by the wave analysis with superposed waves or measured waves at smaller amplitude of incident wave. Discussion is also made on the characteristics of the added resistance in the range of short incident waves
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