Surgical management of proximal fibular tumors: A report of 12 cases

Background/aim Aggressive benign or malignant tumors in the proximal fibula may require en bloc resection of the fibular head, including the peroneal nerve and lateral collateral ligament. Here, we report the treatment outcomes of 12 patients with aggressive benign or malignant proximal fibula tumors. Patients and methods Four patients with osteosarcoma and 1 patient with Ewing\u27s sarcoma were treated with intentional marginal resections after effective chemotherapy, and 4 patients underwent fibular head resections without ligamentous reconstruction. Clinical outcomes were investigated. Results The mean Musculoskeletal Tumor Society scores were 96% and 65% in patients without peroneal nerve resection and those with nerve resection, respectively. No patients complained of knee instability. Conclusion Functional outcomes after resection of the fibular head were primarily influenced by peroneal nerve preservation. If patients are good responders to preoperative chemotherapy, malignant tumors may be treated with marginal excision, resulting in peroneal nerve preservation and good function. © 2016 The AuthorsEmbargo Period 12 month

S-wave impedance measurements of the uppermost material in surface ground layers: Vertical load excitation on a circular disk

S-wave impedance is one of the most effective parameters used to study the ground motion amplification of soil deposits. We propose a new approach to measure the S-wave impedance of the uppermost material in surface ground layers. First, a circular disk is set on the ground surface, and it is vertically loaded by sinusoidal wave excitation. When the time series of the loading velocity is synchronized with the reaction force, the ratio of the reaction force to the loading velocity is proportional to the S-wave impedance. We then estimate the proportionality coefficient from numerical experiments and check its accuracy. The measurement error is estimated to be within 1% for the homogeneous half-space case. We also discuss the applicability of this new approach and its limitations on the basis of numerical experiments for inhomogeneous media: a two-layered medium and a one-dimensional (1-D) random medium. The proposed approach is effective for both cases if we select the appropriate circular disk size

Experimental Set-Up for Evaluation of Electro-Magnetic Characteristics of High-Tc Superconductors Cooled by Liquid Hydrogen

Liquid hydrogen (LH2) has excellent properties as a coolant, such as large latent heat, low viscosity coefficient, etc. Not only MgB2 but also other high-Tc superconductors are expected to have excellent properties when cooled by LH2. It is necessary for a stability design of a high-Tc superconductor cooled by LH2 to make an electro-magnetic characteristic clear. However, due to the handling difficulties of LH2, there are only few papers on the properties of LH2-cooled superconductors, especially under the external magnetic field. In this paper, an experimental set-up is described, which was designed and fabricated for the evaluation of the electro-magnetic characteristics of high-Tc superconductors cooled by LH2. The LH2 cryostat of 309 mm inner diameter was set co-axially with vacuum layer in the LHe cryostat in which the LHe-cooled superconducting magnet for external magnetic field (up to 7 T) was set. The LH2 cryostat has three power leads for feeding up to 500 A to the test high-Tc superconductors

Heat Transfer Characteristics of a Horizontal Wire in Pools of Liquid and Supercritical Hydrogen

Heat transfer from a horizontal wire immersed in both liquid and supercritical hydrogen was measured with a quasi-steady increase of the heat generation rate for a wide range of bath temperatures and pressures. The nucleate boiling heat transfer coefficient is higher for higher pressures. The critical heat flux (CHF) is highest in the vicinity of 0.4 MPa and is expressed by Kutateladze’s equation. The CHFs become higher for higher degrees of subcooling. The heat transfer under supercritical pressures is the same as natural convection heat transfer in liquid hydrogen, but it deteriorates for heated surface temperautres higher than the pseudocritical temperature. The heat transfer correlation was derived based on the experimental data

Transient heat transfer from a wire inserted into a vertically mounted pipe to forced flow liquid hydrogen

Proceedings of the 25th International Cryogenic Engineering Conference and International Cryogenic Materials Conference 2014The transient heat transfer from a Pt-Co wire heater inserted into a vertically mounted pipe, through which forced flow subcooled liquid hydrogen was passed, is measured by increasing the exponential heat input with various time periods at a pressure of 0.7 MPa and an inlet temperature of 21 K. The flow velocities range from 0.8 to 5.5 m/s. For shorter periods, the non-boiling heat transfer becomes higher than that given by the Dittus-Boelter equation due to the transient conductive heat transfer contribution. In addition, the transient critical heat flux (CHF) becomes higher than the steady-state CHF. The effect of the flow velocity and period on the transient CHF heat flux is also clarified

Treatment of a Malignant Soft Tissue Tumor Arising in the Vicinity of the Sciatic Nerve with an In-Situ Preparation Technique and Intensive Multidisciplinary Therapy

Preservation of the sciatic nerve is difficult in cases of highly malignant soft tissuetumors closely surrounding the nerve. Herein, we present the first case of preservation of thisnerve by combining an in-situ preparation technique (ISP; a technique enabling the preparation ofneurovascular bundles without contamination by tumor cells) with intensive concurrent neoadjuvantchemo-radiotherapy with hyperthermia (RHC; radio-hyperthermo-chemotherapy). A 62-year-oldman presented with a soft tissue mass in the right thigh and was diagnosed with undifferentiatedpleomorphic sarcoma. The tumor arose in the multi-compartment areas of the posterior thigh musclesand was closely intertwined with the sciatic nerve. As preoperative therapy, RHC was performedfor surgical down-staging and the tumor partially responded. Afterwards, wide resection of thetumor with preservation of the sciatic nerve using ISP was performed. Following the surgery, therehas not been recurrence in the affected site and the functional outcomes of the lower extremityachieved 80% in the Musculoskeletal Tumor Society score. The patient is still alive with disease fiveyears postoperatively. This is the first case in which ISP and RHC procedures were combined forthe preservation of the neurovascular structure. Further study is needed for the validation of thefeasibility of this method

Critical Current Test of Liquid Hydrogen Cooled HTC Superconductors under External Magnetic Field

High-Tc (HTC) superconductors including MgB2 will show excellent properties under temperature of Liquid Hydrogen (LH2:20K), which has large latent heat and low viscosity coefficient. In order to design and fabricate the LH2 cooled superconducting energy devices, we must clear the cooling property of LH2 for superconductors, the cooling system and safety design of LH2 cooled superconducting devices and electro-magnetic property evaluation of superconductors (BSCCO, REBCO and MgB2) and their magnets cooled by LH2. As the first step of the study, an experimental setup which can be used for investigating heat transfer characteristics of LH2 in a pool and also in forced flow (circulation loop with a pump), and also for evaluation of electro-magnetic properties of LH2 cooled superconductors under external magnetic field (up to 7 T). In this paper, we will show a short sketch of the experimental set-up, practical experiences in safety operation of liquid hydrogen cooling system and example test results of critical current evaluation of HTC superconductors cooled by LH2

Forced Convection Heat Transfer of Liquid Hydrogen Through a 200-mm Long Heated Tube

Superconductivity Centennial Conference, SCC 2011 ; 18 September 2011 through 23 September 2011The heat transfer from the inner side of a vertically- mounted heated tube with a length of 200.0 mm and a diameter of 6.0 mm to a forced flow of liquid hydrogen was measured for wide ranges of flow rate and liquid temperature. The non-boiling heat transfer coefficients agreed well with the Dittus -Boelter equation. The heat fluxes at departure from nucleate boiling (DNB) were higher for higher flow velocities and greater subcooling. The effect of the tube length on the DNB heat flux was clarified through comparison with our previous data. It was confirmed that the experimental data agreed well with the authors' DNB correlation