• Title/Summary/Keyword: MESA

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The Study on Comparison of Clinical Outcomes of Intracytoplasmic Sperm Injection in Patients with Epididymal Sperm and Testicular Sperm (난자 세포질 내 정자 주입술시 부고환 및 고환 정자의 체외수정능력에 관한 비교 연구)

  • Sung, Ki-Cheong;Kang, Moon-Joo;Kim, Hee-Sun;Oh, Sun-Kyung;Ku, Seung-Yup;Suh, Chang-Suk;Kim, Seok-Hyun;Choi, Young-Min;Kim, Jung-Gu;Moon, Shin-Yong
    • Clinical and Experimental Reproductive Medicine
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    • v.30 no.2
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    • pp.119-126
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    • 2003
  • Objective: This study was carried out to compare the clinical outcomes of intracytoplasmic sperm injection (ICSI) in patients with obstructive azoospermia according to sperm retrieval site and technique; microsurgical epididymal sperm aspiration (MESA), percutaneous epididymal sperm aspiration (PESA), testicular sperm extraction by open biopsy (TESE). Methods: The outcomes of ICSI and IVF-ET were evaluated and compared among 3 groups. Seventy three men suffering from infertility due to obstructive azoospermia had 107 ICSI cycles using MESA (21 cycles in 15 patients), PESA (26 cycles in 17 patients) and TESE (60 cycles in 41 patients). Results: In the clinical outcomes in patients undergoing ICSI with epididymal or testicular sperm, there were no significant differences in fertilization rate (66.1% vs. 60.5%), cleavage rate (94.9% vs. 97.6%), cumulative embryo score (CES) (51.3 vs. 58.8), implantation rate (7.9% vs. 6.1), and clinical pregnancy rate per ET (30.4% (14/46) vs. 25.4% (15/59)) between both groups. Also, in the clinical outcomes in ICSI patients using MESA, PESA, TESE, there were no significant differences in fertilization rate (61.8%, 69.4%, 60.5%), cleavage rate (92.1%, 97.3%, 97.6%), CES (38.1, 52.0, 58.8), implantation rate (9.5%, 6.6%, 6.1%), and clinical pregnancy rate per ET (35% (7/20), 26.9% (7/26), 25.4% (15/59)) among 3 groups. Conclusion: When compared with MESA or TESE, PESA, the clinical outcomes were similar in ICSI patients with obstructive azoospermia whatever the origin or the technique of sperm retrieval. However, we considered PESA is more time-saving and cost effective for ICSI in patients with obstructive azoospermia.

An Analytical Model for Deriving the 3-D Potentials and the Front and Back Gate Threshold Voltages of a Mesa-Isolated Small Geometry Fully Depleted SOI MOSFET

  • Lee, Jae Bin;Suh, Chung Ha
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.4
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    • pp.473-481
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    • 2012
  • For a mesa-isolated small geometry SOI MOSFET, the potentials in the silicon film, front, back, and side-wall oxide layers can be derived three-dimensionally. Using Taylor's series expansions of the trigonometric functions, the derived potentials are written in terms of the natural length that can be determined by using the derived formula. From the derived 3-D potentials, the minimum values of the front and the back surface potentials are derived and used to obtain the closed-form expressions for the front and back gate threshold voltages as functions of various device parameters and applied bias voltages. Obtained results can be found to explain the drain-induced threshold voltage roll-off and the narrow width effect of a fully depleted small geometry SOI MOSFET in a unified manner.

Lumbar Periradicular Abscess Mimicking a Fragmented Lumbar Disc Herniation : An Unusual Case

  • Bakar, Bulent;Tekkok, Ismail Hakki
    • Journal of Korean Neurosurgical Society
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    • v.44 no.6
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    • pp.385-388
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    • 2008
  • We herein describe the case of a focal spontaneous spinal epidural abscess who was initially diagnosed to have a free fragment of a lumbar disc. A 71-year-old woman presented with history of low back and right leg pain. Magnetic resonance imaging suggested a peripherally enhancing free fragment extending down from S1 nerve root axilla. Preoperative laboratory investigation showed elevation of c-reactive protein (CRP), erythrocyte sedimentation rate (ESR) levels. She was taken for surgery and a fluctuating mass at the axilla of S1 nerve was found. When the mass was probed with a dissector, a dark yellow, thick pus drained out. Pus cultures were negative. Patients who present with extreme low back plus leg pain and increased leucocyte count, ESR and CRP levels should raise the suspicion of an infection of a vertebral body or spinal epidural space.

Bilateral Chronic Subdural Hematoma Contaminated with Klebsiella Pneumoniae : An Unusual Case

  • Bakar, Bulent;Sungur, Cem;Tekkok, Ismail Hakki
    • Journal of Korean Neurosurgical Society
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    • v.45 no.6
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    • pp.397-400
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    • 2009
  • This article presents the case of a bilateral chronic subdural hematoma which was contaminated with Klebsiella pneumoniae and resulted in a life-threatening central nervous system infection. After repeated of bilateral burr-hole drainage, the patient became hyperpyrexic and drowsy. Suppuration within the subdural space was suspected and then the patient underwent bilateral fronto-temporo-parietal craniotomies, and pus was evacuated. Its cultures revealed Klebsiella pneumoniae. Intravenous meropenem was given for 6 weeks. He recovered completely. Microorganisms like Klebsiella pneumoniae may directly infect the subdural space with iatrogenic contamination.

Design and Fabrication of Laser Diode Integrated with Peltier Cooler (열전 냉각기가 집적된 레이저 다이오드)

  • 이상일;박정호
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.1
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    • pp.159-165
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    • 1995
  • A double-heterostructure mesa-stripe-geometry laser diode integrated with thermoelectric Peltier cooler has been designed and fabricated. Epi-layers have been grown by metal organic chemical vapor deposition(MOCVD) method. Peltier cooling effect has been measured for devices with a mesa width of 14$\mu$m and a cavity length of 380$\mu$m. The effects of thermoelectric cooling could be shown by measuring the optical output of the laser with the increase of the current in the thermoelectric cooler. While the input courrent of the laser was maintained at 250mA, the optical output was decreased from 4.8mW to 3.8mW due to heating, but with the thermoelectric cooler on the optical output power was recovered by more than 40%. The results show that the complicated cooling device is not needed since the cooling can be achevied by the developement of the fabrication processing.

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Microwave plasma emission from tunnel-injected nonequilibrium high-Tc superconductors

  • Lee, Kie-Jin
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.9-14
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    • 2000
  • We report on the novel nonequilibrium nlicrowave emission from quasiparticle-injected high-Tc superconductors. The phenomena have been observed for the current-injected YBCO/I/Au or BSCCO/I/Au thin-film tunnel junctions and BSCCO single-crystal intrinsic Josephson mesa junction samples. For the thin-film tunnel junctions, the emitted radiation appears as broadband. For the intrinsic BSCCO mesa samples, the radiation appears as three different modes of emissions depending on the bias point in the hysteretic current-voltage characteristics; Josephson-emission, nonequilibrium broad emission and sharp coherent microwave emission. The results were interpreted by the Josephson plasma excitation model due to quasiparticle injection.

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Study of n-ZnO/InGaN/p-GaN Lihgt Emitting Diodes

  • Gang, Chang-Mo;Nam, Seung-Yong;Gong, Deuk-Jo;Choe, Sang-Bae;Seong, Won-Seok;Lee, Dong-Seon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.322.2-322.2
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    • 2014
  • Lighting emitting diodes of n-ZnO/MQW/p-GaN structure are fabricated and investigated. To realize this LED structure, n-ZnO/MQW/p-GaN are grown by MOCVD. At several bias voltages, blue-green light is emitted from the ZnO mesa edge. However, the emission is restricted near the mesa edge. It is seen that the hole current does not spread well. It is because conductivity of p-GaN is extremely small. The break down voltage of the device is small compared to conventional InGaN/GaN LEDs. It is seen that ZnO columnar grain boundaries act as leakage current paths and non-radiative recombination center.

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Growth and Characterization of the Multi Quantum Wells by MBE(The Growth and Electrical Properties of Resonant Tunneling Structures) (MBE에 의한 다양자 우물제작 및 특성연구(공명투과 다이오드의 제작과 전기적 특 성))

  • 김순구;강태원;홍치유;정관수;주영도
    • Journal of the Korean Vacuum Society
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    • v.1 no.1
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    • pp.134-138
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    • 1992
  • The GaAs/AlAs double barrier structures was grown by MBE(Mo1ecular Beam Epitaxy). Mesa diode was fabricated and I-V characteristics of the diode were measured by semiconductor parameter analyser at room temperature. TEM pictures show the double barrier structure with abrupt interface. PVCR(Peak to Valley Current Ratio) proves to be independent of barrier thickness. These results show that increase in barrier thickness leads to larger valley current by non-resonant tunneling.

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