85 results on '"I. S. Hwang"'
Search Results
2. The Detection Performance of 18F–Prostate-Specific Membrane Antigen-1007 PET/CT in Primary Prostate Cancer
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Ya-Ting, Huang, Neng-Chuan, Tseng, Yen-Kung, Chen, Kuo-How, Huang, Hsiu-Ying, Lin, Ya-Yao, Huang, Thomas I S, Hwang, and Yen-Chuan, Ou
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Male ,Biopsy ,Lymphatic Metastasis ,Positron Emission Tomography Computed Tomography ,Prostate ,Humans ,Prostatic Neoplasms ,Gallium Radioisotopes ,Radiology, Nuclear Medicine and imaging ,General Medicine - Abstract
Multiple tools are now available to determine the requirement for a biopsy to diagnose prostate cancer, and PET/CT with radiolabeled prostate-specific membrane antigen (PSMA)-targeting radiotracers has been recommended for detecting primary prostate cancer. Particularly, the radiotracer 18 F-PSMA-1007 was found to be more favorable for primary tumors compared with other PSMA-targeting radiotracers because of its low clearance via the urinary tract and better image resolution. Thus, we performed a systematic review and meta-analysis to more accurately evaluate the detection performance of 18 F-PSMA-1007 PET/CT in primary prostate cancer patients.An update on the databases of PubMed/MEDLINE, EMBASE, and Cochrane Library for comprehensive literature search was performed on September 30, 2021. The pooling detection rate was calculated on a per-patient basis. The pooling median of the SUV max was analyzed from the included studies. Furthermore, the positive predictive value of 18 F-PSMA-1007 PET/CT with pathologic lesions was analyzed using the criterion standard.Twelve studies (540 patients total) were included in the meta-analysis. The overall pooling detection rate of 18 F-PSMA-1007 per patient was 94%, and the pooling median of SUV max located at the intraprostate tumor was 16 (range, 3.7-77.7). The positive predictive value of 18 F-PSMA-1007 per lesion with histopathological validation was 0.90, detecting regional lymph node metastasis was 0.94, and detecting localized prostatic tumors was 0.84.In the current meta-analysis, we revealed the excellent performance of 18 F-PSMA-1007 to detect localized prostatic tumor lesions and regional lymph node metastasis. Moreover, the uptake of localized tumors in primary prostate cancer was nearly liver uptake and may be considered a suspicious malignancy if it was equal to or greater than the liver uptake.
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- 2022
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3. Vibrational dephasing in matter-wave interferometers
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A Rembold, G Schütz, R Röpke, W T Chang, I S Hwang, A Günther, and A Stibor
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matter-wave interferometry ,dephasing ,vibration ,correlation analysis ,sensor technology ,spectrum analysis ,Science ,Physics ,QC1-999 - Abstract
Matter-wave interferometry is a highly sensitive tool to measure small perturbations in a quantum system. This property allows the creation of precision sensors for dephasing mechanisms such as mechanical vibrations. They are a challenge for phase measurements under perturbing conditions that cannot be perfectly decoupled from the interferometer, e.g. for mobile interferometric devices or vibrations with a broad frequency range. Here, we demonstrate a method based on second-order correlation theory in combination with Fourier analysis, to use an electron interferometer as a sensor that precisely characterizes the mechanical vibration spectrum of the interferometer. Using the high spatial and temporal single-particle resolution of a delay line detector, the data allows to reveal the original contrast and spatial periodicity of the interference pattern from ‘washed-out’ matter-wave interferograms that have been vibrationally disturbed in the frequency region between 100 and 1000 Hz. Other than with electromagnetic dephasing, due to excitations of higher harmonics and additional frequencies induced from the environment, the parts in the setup oscillate with frequencies that can be different to the applied ones. The developed numerical search algorithm is capable to determine those unknown oscillations and corresponding amplitudes. The technique can identify vibrational dephasing and decrease damping and shielding requirements in electron, ion, neutron, atom and molecule interferometers that generate a spatial fringe pattern on the detector plane.
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- 2017
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4. Autophagy regulation in bladder cancer as the novel therapeutic strategy
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Ji-Fan Lin and Thomas I. S. Hwang
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Cancer Research ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2017
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5. Two invariant subspaces and spectral properties of a linear operator
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S.V. Djordjević, I. S. Hwang, and B.P. Duggal
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Linear map ,Pure mathematics ,Multiplication operator ,Spectral radius ,Applied Mathematics ,Spectral properties ,Reflexive operator algebra ,Invariant (mathematics) ,Linear subspace ,Analysis ,Continuous linear operator ,Mathematics - Published
- 2016
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6. 34 The effect of dilution method of beagle dog semen on the survival rate of cryopreserved spermatozoa after thawing
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Y. G. Ko, I. S. Hwang, C.-L. Kim, I. S. Jeon, and Sung Woo Kim
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endocrine system ,medicine.diagnostic_test ,urogenital system ,Semen ,Reproductive technology ,Semen analysis ,Biology ,Beagle ,Cryopreservation ,Dilution ,Drug detection ,Andrology ,fluids and secretions ,Endocrinology ,Reproductive Medicine ,Reproductive biology ,Genetics ,medicine ,Animal Science and Zoology ,Molecular Biology ,Developmental Biology ,Biotechnology - Abstract
The successful cryopreservation of spermatozoa of the beagle dog for AI is essential for the establishment of the genetic banks of drug detection dogs. The beagle dog is widely used for drug testing and chosen for breeding by breeders. However, the use of cryopreserved beagle semen is limited by the lower number of offspring of dog species. In this study, 3 highly trained beagle dogs were chosen and their semen was cryopreserved for the next generation. The effects of dilution methods of beagle semen were tested using a direct dilution method at RT and a 2-step dilution method at 5°C. As a control group, the effects of a direct dilution method of semen on the percentage of motile sperm and progressive motility were analysed by computer-assisted semen analysis system (SAIS, Korea), and abnormality of spermatozoa was examined by Diff Quik staining. A total of 9 samples from 3 dogs were extended in 4% glycerol containing Tris-egg yolk diluents at approximately 22 to 25°C. The diluted semen was cooled to 5°C within 2h. The packed 0.5-mL straws were placed 5cm above the surface of LN for 10min and then plunged in. A 2-step dilution method was conducted using the same procedures of freezing, but the first dilution was done with glycerol-free diluent. After cooling to 5°C within 2h, the second diluent with 8% glycerol was added to the same volume of diluted semen at 5°C and stabilised for 1h. After thawing for 45s at 37°C, the semen from the 2-step dilution method showed the higher percentage of motile sperm (65.4±6% v. 45.3±8%; P
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- 2019
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7. The Potential of the LFR and the ELSY Project
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S. Monti, Gianluca Benamati, D. Struwe, A. Orden, Craig F. Smith, James J. Sienicki, H. Ait Abderrahim, L. Cinotti, I. S. Hwang, G. Locatelli, and H. Wider
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Engineering ,Electricity generation ,Plant efficiency ,Fissile material ,Waste management ,business.industry ,Nuclear engineering ,Load following power plant ,Capital cost ,Thermal power station ,Minor actinide ,business ,Reactor pressure vessel - Abstract
This paper presents the current status of the development of the Lead-cooled Fast Reactor (LFR) in support of Generation IV (GEN IV) Nuclear Energy Systems. The approach being taken by the GIF plan is to address the research priorities of each member state in developing an integrated and coordinated research program to achieve common objectives, while avoiding duplication of effort. The integrated plan being prepared by the LFR Provisional System Steering Committee of the GIF, known as the LFR System research Plan (SRP) recognizes two principal technology tracks for pursuit of LFR technology: (1) a small, transportable system of 10-100 MWe size that features a very long refueling interval, (2) a larger-sized system rated at about 600 MWe, intended for central station power generation and waste transmutation. This paper, in particular, describes the ongoing activities to develop the Small Secure Transportable Autonomous Reactor (SSTAR) and the European Lead-cooled SYstem (ELSY), the two research initiatives closely aligned with the overall tracks of the SRP and outlines the Proliferation-resistant Environment-friendly Accident-tolerant Continual & Economical Reactors (PEACER) conceived with particular focus on burning/transmuting of long-living TRU waste and fission fragments of concern, such as Tc and I. The current reference design for themore » SSTAR is a 20 MWe natural circulation pool-type reactor concept with a small shippable reactor vessel. Specific features of the lead coolant, the nitride fuel containing transuranics, the fast spectrum core, and the small size combine to promote a unique approach to achieve proliferation resistance, while also enabling fissile self-sufficiency, autonomous load following, simplicity of operation, reliability, transportability, as well as a high degree of passive safety. Conversion of the core thermal power into electricity at a high plant efficiency of 44% is accomplished utilizing a supercritical carbon dioxide Brayton cycle power converter. The ELSY reference design is a 600 MWe pool-type reactor cooled by pure lead. This concept has been under development since September 2006, and is sponsored by the Sixth Framework Programme of EURATOM. The ELSY project is being performed by a consortium consisting of twenty organizations including seventeen from Europe, two from Korea and one from the USA. ELSY aims to demonstrate the possibility of designing a competitive and safe fast critical reactor using simple engineered technical features while fully complying with the Generation IV goal of minor actinide (MA) burning capability. The use of a compact and simple primary circuit with the additional objective that all internal components be removable, are among the reactor features intended to assure competitive electric energy generation and long-term investment protection. Simplicity is expected to reduce both the capital cost and the construction time; these are also supported by the compactness of the reactor building (reduced footprint and height). The reduced footprint would be possible due to the elimination of the Intermediate Cooling System, the reduced elevation the result of the design approach of reduced-height components.« less
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- 2007
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8. Calibration of YSZ Oxygen Sensor for Use in a Lead-alloy Coolant System
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S. H. Lee, C. H. Cho, I. S. Hwang, and T. Y. Song
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Materials science ,chemistry ,Metallurgy ,Electrochemistry ,chemistry.chemical_element ,Limiting oxygen concentration ,Electrolyte ,Oxygen sensor ,Oxygen ,Yttria-stabilized zirconia ,Corrosion ,Coolant ,Eutectic system - Abstract
Liquid lead-bismuth eutectic (LBE) may see extensive use as a coolant fluid, and perhaps also as a spallation target, in the next generation nuclear energy system. However, it is very corrosive to the common steels used in nuclear installations. This corrosion problem can be prevented by the formation of a protective oxide layer on the exposed surface of steel. For this purpose, accurately measuring and controlling the oxygen concentration in liquid LBE is very important. Electrochemical oxygen sensors with In/In 2O3 and Bi/Bi 2O3 reference systems can be used as in situ devices for measuring the oxygen concentration in liquid LBE. YSZ (Yttria Stabilized Zirconia) oxygen sensor with molten bismuth saturated with oxygen as a reference, has been selected to measure the oxygen concentration in LBE coolant system. The oxygen concentration difference across the solid electrolyte and the resultant oxygen ion conduction inside the electrolyte establish an electromagnetic force (EMF) that is used to measure the ppb level of dissolved oxygen concentration in liquid LBE. In this paper, the sensitivity of an YSZ oxygen sensor has been evaluated. Sensor calibration curves in liquid LBE at 450 o C have been obtained.
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- 2007
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9. Saturation throughput analysis in IEEE 802.11 DCF using semi-Markov model
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I-S. Hwang and C.-A. Chen
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- 2006
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10. Effect of the Electrochemical Corrosion Potential of Copper on Plugging of Generator Water-Cooling Circuits
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I. S. Hwang, J. Stein, K.-T. Kim, I.H. Rhee, B. C. Syrett, and B.G. Park
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Phase boundary ,Materials science ,General Chemical Engineering ,Metallurgy ,Oxide ,chemistry.chemical_element ,General Chemistry ,Critical value ,Copper ,Corrosion ,chemistry.chemical_compound ,chemistry ,Water cooling ,General Materials Science ,Erosion corrosion of copper water tubes ,Electrochemical potential - Abstract
A large-scale simulation of copper corrosion has been conducted using ohmically heated hollow copper strands that were connected to a physicochemically scale-downed generator water-cooling circuit to identify susceptible conditions in the domain of operating variables, and to understand the detailed mechanism(s) of plugging and clogging. The effect of the electrochemical corrosion potential (ECP) of copper on the plugging of generator water-cooling circuits has been identified through the simulation experiment. The experimental results exhibited that the ECP change across a critical value can trigger a massive release of particulate corrosion products followed by the plugging of a hollow copper strand in stator winding. The critical ECP at which a release of particulate corrosion products is caused corresponds to the phase boundary between cuprous oxide (Cu2O) and cupric oxide (CuO).
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- 2005
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11. ANAMMOX and partial denitritation in anaerobic nitrogen removal from piggery waste
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I.-S. Hwang, Young-Ho Ahn, and K.-S. Min
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Environmental Engineering ,Chemistry ,Environmental engineering ,chemistry.chemical_element ,Biomass ,Pulp and paper industry ,Nitrogen ,chemistry.chemical_compound ,Anammox ,Bioreactor ,Ammonium ,Nitrite ,Water Science and Technology ,Waste disposal ,Mesophile - Abstract
The anaerobic ammonium removal from a piggery waste with high strength (56 g COD/L and 5 g T-N/L) was investigated using a lab-scale upflow anaerobic sludge bed reactor at a mesophilic condition. Based on the nitrogen and carbon balance in the process, the contribution of autotrophic and heterotrophic organisms was also evaluated in terms of the influent NO2-N/NH4-N ratio (1:0.8 and 1:1.2 for Phase 1 and Phase 2, respectively). The result of this research demonstrates that the anaerobic ammonium removal from the piggery waste, using the UASB reactor, can be performed successfully. Furthermore, it appears that by using granular sludge as the seed biomass, the ANAMMOX reaction can start more quickly. Average nitrogen conversion was 0.59 kg T-N/m3 reactor-day (0.06 kg T-N/kg VSS/day) and 0.66 kg T-N/m3 reactor-day (0.08 kg T-N/kg VSS/day) for Phase 1 and Phase 2. The NO2-N/NH4-N removal ratio by the ANAMMOX was 1.48 and 1.79 for Phase 1 and Phase 2. The higher nitrite contents (about 50%) in the substrate resulted in higher nitrite nitrogen removal by the partial denitritation, as well as the ANAMMOX reaction, implying higher potential of partial denitritation. However, the result reveals that the ANAMMOX reaction was influenced less by the degree of partial denitritation, and the ANAMMOX bacteria did not compete with denitritation bacteria. The colour of the biomass at the bottom of the reactor changed from dark gray to dark red, which was accompanied by an increase in cytochrome content. At the end of the experiment, red-coloured granular sludge with diameter of 1-2 mm at the lower part of the reactor was also observed.
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- 2004
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12. A built-in bearing sensor to measure the shaft motion of a small rotary compressor for air conditioning
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H.-J. Ahn, I.-S. Hwang, and Dong-Chul Han
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Engineering ,Bearing (mechanical) ,Steady state (electronics) ,business.industry ,Mechanical Engineering ,Acoustics ,Measure (physics) ,Relative permittivity ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,law.invention ,Piston ,Mechanics of Materials ,law ,Air conditioning ,Control theory ,Transient (oscillation) ,business ,Gas compressor - Abstract
It is very difficult to measure the shaft motion of a small rotary compressor because of mounting space availability, exposure to high temperature and high pressure as well as electromagnetic noise from the motor. This paper details the development of a built-in bearing sensor to measure the shaft motion of a rolling piston type compressor for an air conditioner. The bearing sensor is calibrated indirectly through measuring the oil relative permittivity. The shaft motions in both transient and steady state conditions are measured successfully using this built in bearing sensor.
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- 2003
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13. The Preparation and Characterization of Small Mesopores in Siloxane-Based Materials That Use Cyclodextrins as Templates
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Jingyu Hyeon-Lee, Seok Chang, Sang Kook Mah, Hyun-Dam Jeong, Jin-Heong Yim, Y.-Y. Lyu, Jozeph Park, I.-S. Hwang, Sunghoon Song, J.N. Sun, David W. Gidley, and Y. F. Hu
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Materials science ,Percolation threshold ,Dielectric ,engineering.material ,Condensed Matter Physics ,Silsesquioxane ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Coating ,Siloxane ,Polymer chemistry ,Electrochemistry ,engineering ,Spectroscopy ,Mesoporous material ,Refractive index - Abstract
Porous thin films containing very small closed pores (∼ 20 A) with a low dielectric constant (∼ 2.0) and excellent mechanical properties have been prepared using the mixture of cyclic silsesquioxane (CSSQ) and a new porogen, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (tCD). The pore sizes vary from 16.3 A to 22.2 A when the content of tCD in the coating mixture increases to 45 wt.-% according to positronium annihilation lifetime spectroscopy (PALS) analysis. It has also been found that the pore percolation threshold (the onset of pore interconnectivity) occurs as the ∼ 50 % tCD porogen load. The dielectric constants (k = 2.4 ∼ 1.9) and refractive indices of these porous thin films decreased systematically as the amount of porogen loading increased in the coating mixture. The electrical properties and mechanical properties of such porous thin films were fairly good as interlayer dielectrics.
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- 2003
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14. Modeling of the optical anisotropy of a dye polarizer
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I. S. Hwang and Sang Eon Han
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chemistry.chemical_classification ,Quantitative Biology::Biomolecules ,Materials science ,Polymers and Plastics ,business.industry ,Physics::Optics ,Concentration effect ,Polymer ,Polarizer ,Condensed Matter Physics ,Molecular physics ,law.invention ,Condensed Matter::Soft Condensed Matter ,Distribution function ,Optics ,chemistry ,law ,Orientation (geometry) ,Materials Chemistry ,Transmittance ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,business ,Anisotropy ,Elliptical distribution - Abstract
A new model has been developed to account for the dependence of the optical anisotropy of a dye polarizer on the dye concentration. The effect of the dye concentration has been studied through an examination of the changes in the orientation distribution of the polymer. The model takes into account the intrinsic optical anisotropy of the dichroic dye, the polymer orientation, the polymer orientation distribution, and the dye orientation with respect to the polymer. It is assumed that (1) the orientation distribution function of the polymer segments can be expressed as an elliptical distribution function and that (2) the free rotation of each dye molecule on its axis is suppressed because of the attraction force between the dye molecules and the polymer chains. The pseudo-order parameter, which takes into account the aforementioned assumptions, determines the relation between single-piece transmittance and polarizing efficiency. The orientation distribution of the polymer molecules in the experiment and its effect on the optical performance of a polarizer are quantitatively determined. The model predicts that the effect of the orientation distribution becomes more significant as the polymer chains are oriented more highly. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1363–1370, 2002
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- 2002
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15. Quantitative EMG analysis to investigate synergistic coactivation of ankle and knee muscles during isokinetic ankle movement. Part 2: time frequency analysis
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I S, Hwang and L D, Abraham
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Adult ,Male ,Motor Neurons ,Recruitment, Neurophysiological ,Knee Joint ,Electromyography ,Movement ,Biophysics ,Neuroscience (miscellaneous) ,Humans ,Female ,Neurology (clinical) ,Muscle, Skeletal ,Ankle Joint ,Muscle Contraction - Abstract
Fundamental to intralimb coordination in the lower extremity, ankle-knee synergy induced by motor irradiation has long been employed to secure facilitation of paralyzed muscles. This study, a companion research subsequent to the time amplitude analysis of surface electromyography in part 1, was to investigate the recruitment strategy of irradiated muscles and prime movers during ankle isokinetic contraction at different contraction speeds (30, 60, 120 and 240 degrees/s) with time frequency analysis. The results indicated the recruitment strategies of the major irradiated muscles (ipsilateral rectus femoris/ipsilateral biceps femoris) and prime movers (anterior tibialis/gastrocnemius) were time-dependent and significantly different in terms of the instantaneous median frequency. In general, the prime movers for ankle isokinetic concentric contraction demonstrated a similar recruitment strategy, irrespective of different contraction speeds. This finding is consistent with the idea of generalized motor programs that speed is one of the constraint parameters supplied to motor programs. Nevertheless, the recruitment strategies of the irradiated muscles were highly inconsistent, varying across trials at different contraction speeds, and were not relevant to those of the prime movers. In addition, the recruitment in the irradiated muscles seemly limited to motor units of low threshold, in spite of maximal voluntary contraction of the prime movers.
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- 2001
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16. Control of Alkaline Stress Corrosion Cracking in Pressurized-Water Reactor Steam Generator Tubing
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I. S. Hwang and I.-G. Park
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Materials science ,General Chemical Engineering ,Metallurgy ,Pressurized water reactor ,Boiler (power generation) ,chemistry.chemical_element ,Nimonic ,General Chemistry ,Intergranular corrosion ,Copper ,Corrosion ,law.invention ,chemistry ,law ,Boiling ,General Materials Science ,Stress corrosion cracking - Abstract
Outer-diameter stress corrosion cracking (ODSCC) of alloy 600 (UNS N06600) tubings in steam generators of the Kori-1 pressurized-water reactor (PWR) caused an unscheduled outage in 1994. Failure analysis and remedy development studies were undertaken to avoid a recurrence. Destructive examination of a removed tube indicated axial intergranular cracks developed at the top of sludge caused by a boiling crevice geometry. A high ODSCC propagation rate was attributed to high local pH and increased corrosion potential resulting from oxidized copper presumably formed during the maintenance outage and plant heatup. Remedial measures included: (1) crevice neutralization by crevice flushing with boric acid (H3BO3) and molar ratio control using ammonium chloride (NH4Cl), (2) corrosion potential reduction by hydrazine (H2NNH2) soaking and suppression of oxygen below 20 ppb to avoid copper oxide formation, (3) titanium dioxide (TiO2) inhibitor soaking, and (4) temperature reduction of 5°C. Since application o...
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- 1999
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17. Low-Energy Electron Diffractive Imaging Based on a Single-Atom Electron Source
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I.-S. Hwang, W.-T. Chang, C.-Y. Lin, and W.-H. Hsu
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Instrumentation - Published
- 2015
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18. Damping regulation of the wrist joint at different postural demands
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M.L. Hsu and I.-S. Hwang
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medicine.medical_specialty ,medicine.anatomical_structure ,Physical medicine and rehabilitation ,Computer science ,medicine ,Physical Therapy, Sports Therapy and Rehabilitation ,Wrist ,Joint (geology) - Published
- 2015
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19. AC Impedance Characteristics of Oxide Film on Zirconium
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I. S. Hwang, I. Y. Lim, and Byungchan Han
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Corrosion potential ,Nuclear power industry ,Zirconium ,chemistry.chemical_compound ,Materials science ,chemistry ,Metallurgy ,Oxide ,chemistry.chemical_element ,Ac impedance ,Dielectric spectroscopy - Published
- 2013
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20. 2.4.2 Single-particle detection with micro-/nanocantilevers based sensors
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I. Stachiv, I.-S. Hwang, Y.-L. Chen, and C.-W. Yang
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Cantilever ,Materials science ,business.industry ,Nanocantilever ,Nanowire ,Mechanics ,Structural engineering ,Carbon nanotube ,Viscous liquid ,law.invention ,Flexural strength ,Position (vector) ,law ,Particle ,business - Abstract
We present a theoretical analysis of micro-/nanocantilever based sensors for detection of a particle in vacuum and in viscous fluid. Ultra-high sensitivity detection in fluid will provide better understanding of realistic behavior of molecules and biomolecules in a native environment. We derive simple expressions for the resonant frequency shift accounting for an attached mass in vacuum and viscous fluid. We show that by detecting the first flexural and torsional modes of the cylindrical cantilever (e.g. carbon nanotube or nanowire) the attached mass and position can be accurately resolved. For other cantilever geometries (i.e. rectangular shape, V-shape, etc.) two flexural and torsional modes are needed to determine the mass and the position of the attached particle.
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- 2012
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21. Hydrogen transport in nickel-base alloys
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R. M. Gates, Ronald G. Ballinger, M. Psaila-Dombrowski, A. Turnbull, I. S. Hwang, and M. M. Morra
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Materials science ,Hydrogen ,Precipitation (chemistry) ,Metallurgy ,Alloy ,Metals and Alloys ,chemistry.chemical_element ,Permeation ,engineering.material ,Condensed Matter Physics ,Thermal diffusivity ,Carbide ,Nickel ,chemistry ,Mechanics of Materials ,engineering ,Grain boundary - Abstract
The electrochemical permeation technique has been used to characterize hydrogen transport and trapping in pure nickel and in alloys 600, X-750, and 718 at a temperature of 80 °C. The “effective diffusivity” of hydrogen atoms in alloy 600 is reduced by a factor of about 5 compared to pure nickel. This is attributed to both compositional changes and the presence of [(Ti, Nb)C] carbides. Aging of alloy 600, with subsequent M23C6 carbide precipitation, does not significantly influence the measured “effective diffusivity,” which is explained by the dominant effect of preexisting [(Ti, Nb)C] carbides. The “effective diffusivity” of hydrogen atoms in solution-annealed alloy X-750 is reduced by a factor of about 9 compared to that of pure nickel. This is also attributed to compositional changes and [(Ti,Nb)C] carbides. Aging of alloy X-750, which causes precipitation of γ’[Ni3(Al, Ti)], reduces the “effective diffusivity” by an additional factor of 5 or more. Double aging at 885 °C/24 hours, 704 °C/20 hours following hot working yields the greatest reduction in “effective diffusivity.” Analysis of permeation transients using a diffusiontrapping model indicates a binding energy associated with trapping due to the γ’ phase of between-31 and -37 kJ/mol. The “effective diffusivity” of hydrogen in alloy 718 is about 40 pct greater than for alloy X-750 for the same double and direct aging treatments. The average “effective diffusivities” of the double-aged and direct-aged alloy 718 are comparable, but the permeation transients for the double-aged treatment are significantly steeper. The double-aged treatment with predominantly S phase (orthorhombic Ni3Nb) yields a binding energy of about-30 kJ/mol. Analysis of the direct aged-treated 718, which contains predominantly γ′ phase (body-centered tetragonal Ni3Nb) gave a binding energy between -23 and -27 kJ/mol. Segregation of hydrogen atoms to the γ′/matrix interface, combined with a large volume fraction ofγ at grain boundaries, provides the most likely explanation for the enhanced cracking associated with the double-aging treatment in alloy X-750.
- Published
- 1992
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22. INCOLOY 908, a low coefficient of Expansion Alloy for High-Strength Cryogenic Applications: Part I. Physical Metallurgy
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I. S. Hwang, M. M. Morra, and Ronald G. Ballinger
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Materials science ,Metallurgy ,Alloy ,Metals and Alloys ,Atmospheric temperature range ,engineering.material ,Condensed Matter Physics ,Microstructure ,Thermal expansion ,Superalloy ,Mechanics of Materials ,Transmission electron microscopy ,Phase (matter) ,Scanning transmission electron microscopy ,engineering ,Incoloy - Abstract
INCOLOY 908 is a low coefficient of thermal expansion (COE) iron-nickel base superalloy that was developed jointly by The Massachusetts Institute of Technology and the International Nickel Company for cryogenic service. The alloy is stable against phase transformation during prolonged thermal treatments and has a COE compatible with that of Nb3Sn. These properties make the material ideal for use as a structural component in superconducting magnets using Nb3Sn. The evolution of microstructure has been studied as a function of time at temperature over the temperature range of 650 °C to 900 °C for times between 50 and 200 hours. A detailed analysis of precipitated phases has been conducted using X-ray diffraction (XRD), transmission electron microscopy (TEM), and analytical scanning and scanning transmission electron mi- croscopy (STEM) techniques. The primary strengthening phase has been found to be γ′, Ni3(Al, Ti). INCOLOY 908 is stable against overaging, which is defined as the transformation of γ′ to η, Ni3Ti, for times to 100 hours at temperatures up to 750 °C. Upon overaging, the strengthening phase transforms to η. A new phase,H x , has been identified and characterized.
- Published
- 1992
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23. Comparison of Effects following the Intracorporeal Injection of Papaverine and Prostaglandin E1
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Jang-Kwang Chen, Thomas I. S. Hwang, and Chi-Rei Yang
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Adult ,Male ,Time Factors ,Urology ,medicine.medical_treatment ,Injections, Intramuscular ,chemistry.chemical_compound ,Erectile Dysfunction ,Papaverine ,medicine ,Humans ,Alprostadil ,Prostaglandin E1 ,Aged ,Aged, 80 and over ,Chemotherapy ,business.industry ,Penile Erection ,Significant difference ,Middle Aged ,respiratory system ,chemistry ,Anesthesia ,lipids (amino acids, peptides, and proteins) ,Onset of action ,business ,circulatory and respiratory physiology ,medicine.drug - Abstract
A study group of 240 impotent men receiving intracorporeal injections were divided into 2 groups: the first group received papaverine (60 mg) and the second prostaglandin E1 (PGE1 20 micrograms). The effect of the drugs was evaluated according to the onset of erection, rigidity and the duration of erection; 136 patients were treated with papaverine and 104 with PGE1. The onset of action in these groups was 6.42 +/- 5.39 vs 10.14 +/- 5.41 min; the rigidity score was 3.37 +/- 0.89 vs 3.60 +/- 1.10 and the duration of erection was 49.56 +/- 62.56 vs 63.60 +/- 44.57 min respectively. There was a significant difference in the onset of action (PGE1 was slower than papaverine) and maintenance of erection (longer with PGE1 than with papaverine). Another group of 17 patients received both papaverine and PGE1. The effects of papaverine were better in 4 cases, worse in 5 and equal to PGE1 in 8. This study indicates that compared with papaverine, treatment with PGE1 produces a slower onset of action, a longer duration of erection and fewer side effects.
- Published
- 1992
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24. A multi-frequency AC potential drop technique for the detection of small cracks
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I S Hwang
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Reproducibility ,Materials science ,Fissure ,business.industry ,Applied Mathematics ,Drop (liquid) ,Strain rate ,Cracking ,medicine.anatomical_structure ,Optics ,Dynamic loading ,Ultimate tensile strength ,medicine ,business ,Instrumentation ,Engineering (miscellaneous) ,Voltage drop - Abstract
DC potential drop techniques have been widely used to measure crack length. However, the sensitivity of this technique is often insufficient for detection of small cracks initiating from a smooth surface. By using a multi-frequency AC potential drop technique, a resolution of 50 mu m has been achieved for multiple crack initiation with a probe spacing of 10 mm during slow strain rate tensile tests. The sensitivity is reduced for single crack initiation for a given probe spacing. For single crack initiation 50 mu m resolution is obtained by decreasing the probe spacing to 1.2 mm. Data reproducibility is found to be adequate when probe spacing and configurations are made consistently. The technique has been applied to environment-assisted cracking tests of nickel-base alloys at 350 degrees C in water using both static and dynamic loading.
- Published
- 1992
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25. Analyses of Palladium Cathodes Used for Heavy Water Electrolysis
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K. Kumar, I. S. Hwang, Ronald G. Ballinger, A. Stecyk, and C. R. Dauwalter
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Equiaxed crystals ,Electrolysis ,Materials science ,020209 energy ,General Engineering ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Abnormal grain growth ,Microstructure ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Secondary ion mass spectrometry ,chemistry ,law ,Phase (matter) ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Grain boundary ,Palladium - Abstract
This paper reports on the sporadic nature of the excess heat reported from heavy water electrolysis which has attributed to variability among the different palladium cathodes used. Experimental repeatability should, therefore, be enhanced if the microstructure of the palladium can be controlled. Toward this end, palladium rod samples from two heavy water electrolysis experiments were compared to a sample representative of the as-installed condition. The samples examined showed equiaxed grains and significant abnormal grain growth. The rod axes had strong textures, which were attributed to their prior thermomechanical history. The postelectrolysis palladium rods were sampled at two locations that were suspected to have operated at different average current densities. The suspected higher current density regions consisted of single-phase Pd-D{sub 0.7} microstructures. Surface-originated cracks were seen along the grain boundaries in one of two such specimens. Cracks were absent in samples from the suspected lower current density regions, which showed two-phase microstructures with Pd-D{sub 0.7} as the dominant phase. The minor phase, indexed as palladium in the X-ray pattern, was dispersed nonuniformly, mostly in the form of stringers, across the grain boundaries. It is concluded that high current densities resulted in high deuterium loadings in palladium. Smoothing effects from the electrolyticmore » process, resulting in preferential material removal from the grain boundaries, were seen on the cathode surface. A number of high-mass impurities were seen to have deposited on the exposed surface. An initial secondary ion mass spectrometry examination of the specimen interior indicated a significant presence of mass 2 species and considerably lower concentrations of mass 3 and 4 species. Repeat analyses failed to confirm the presence of the mass 3 and 4 species.« less
- Published
- 1991
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26. Authors
- Author
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Norman R. Schulze, J. Reece Roth, D. Galambos, Y.-K. Martin Peng, George H. Miley, Heinrich Hora, Lorenzo Cicchitelli, Gregorios V. Kasotakis, Robert J. Sterling, Michael L. Browne, Francesco Bombi, John Mandrekas, W. M. Stacey, Augusta Airoldi, Giovanna Cenacchi, Satoshi Nishio, Kichiro Shinya, Michael J. Gouge, Wayne A. Houlberg, Stanley L. Milora, Thanh Q. Hua, Basil F. Picologlou, Mamoru Matsuoka, Hiroshi Horiike, Takao Itoh, Mikito Kawai, Mitsuru Kikuchi, Masaaki Kuriyama, Makoto Mizuno, Shigeru Tanaka, R. N. Dexter, D. W. Kerst, T. W. Lovell, S. C. Prager, J. C. Sprott, Shigeo Numata, Yasuhiko Fujii, Makoto Okamoto, Steven J. Piet, Edward T. Cheng, Steve Fetter, J. Stephen Herring, J. Rand McNally, Wladyslaw Zakowicz, Yeong E. Kim, Robert A. Rice, Gary S. Chulick, K. Kumar, I. S. Hwang, R. G. Ballinger, C. R. Dauwalter, A. Stecyk, Joaquin Sevilla, Francisco Fernandez, Beatriz Escarpizo, Carlos Sánchez, Kenneth A. Ritley, Kelvin G. Lynn, Peter Dull, Marc H. Weber, Michael Carroll, and James J. Hurst
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General Engineering - Published
- 1991
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27. Measurement and analysis of neutron and gamma-ray emission rates, other fusion products, and power in electrochemical cells having Pd cathodes
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K. W. Wenzel, Paul S. Linsay, M.P.J. Gaudreau, Xing Chen, Vince Cammarata, Mark S. Wrighton, C.L. Fiore, Ronald R. Parker, David Albagli, S. C. Luckhardt, Ron Ballinger, I. S. Hwang, Richard M. Crooks, R. D. Petrasso, Martin O. Schloh, and C. K. Li
- Subjects
Nuclear and High Energy Physics ,Materials science ,Analytical chemistry ,Gamma ray ,Cathode ,Electrochemical cell ,law.invention ,Cold fusion ,Nuclear Energy and Engineering ,X-ray photoelectron spectroscopy ,law ,Nuclear fusion ,Neutron ,Atomic physics ,Spectroscopy - Abstract
Results of experiments intended to reproduce cold fusion phenomena originally reported by Fleischmann, Pons, and Hawkins are presented. These experiments were performed on a pair of matched electrochemical cells containing 0.1×9 cm Pd rods that were operated for 10 days. The cells were analyzed by the following means: (1) constant temperature calorimetry, (2) neutron counting and γ-ray spectroscopy, (3) mass spectral analysis of4He in effluent gases, and4He and3He within the Pd metal, (4) tritium analysis of the electrolyte solution, and (5) x-ray photoelectron spectroscopy of the Pd cathode surface. Within estimated levels of accuracy, no excess power output or any other evidence of fusion products was detected.
- Published
- 1990
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28. Applications of Robotics to Assessment and Physical Therapy of Upper Limbs of Stroke Patients
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P. C. Kung, S. M. Chen, Z. W. Wu, I. S. Hwang, M. S. Ju, and C. C. K. Lin
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medicine.medical_specialty ,Rehabilitation ,Stroke patient ,business.industry ,Modified Ashworth scale ,medicine.medical_treatment ,fungi ,technology, industry, and agriculture ,food and beverages ,Robotics ,medicine.disease ,Physical medicine and rehabilitation ,medicine ,Physical therapy ,Spasticity ,Artificial intelligence ,medicine.symptom ,business ,Motor learning ,human activities ,Stroke ,Neurorehabilitation - Abstract
5-1 Advantages and Disadvantages of Robotics for Rehabilitation of Stroke Patients One may find that robotics provides an integral solution to the treatments and objective assessments of some neurological diseases such as stroke. The robots can perform repeated treatment protocols without the need of continuous involvement of therapists. A robot can save therapists' arduous efforts by helping with heavy, challenging and repetitious movements. Physical strain and professional injury in therapists can be minimized. It is cost-effective to strengthen some basic elements, such as muscle strength, range of motion, and sensorimotor coordination, in preparation for higher skill-level movement patterns on a mass-practice basis. Robotic therapy techniques can mimic appropriate functional kinematics or apply novel patterns of force with precision, such as isokinetic contraction, that are potentially effective for muscle strengthening. More advanced robots can even provide tactile feedback that kinetically and kinematically corrects the impaired movements. Data collected during the robot training sessions can be quantified with ease to complement the subjective and qualitative observation of clinicians.
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- 2007
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29. Physiological aspects of MMG and EMG spectra during load-varying isometric dorsiflexion
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I S, Hwang
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Adult ,Male ,Motor Neurons ,Electromyography ,Motor Skills ,Isometric Contraction ,Physical Exertion ,Task Performance and Analysis ,Action Potentials ,Humans ,Female ,Muscle, Skeletal ,Adaptation, Physiological - Abstract
The aim of the study was to examine spectral features of the mechanomyogram (MMG) and electromyogram (EMG) during static and load-varying isometric dorsiflexion to characterize force control strategies of the tibialis anterior. Twelve healthy subjects performed two motor tasks including 1) four exertion levels of static isometric dorsiflexion and 2) load-varying isometric dorsiflexion while tracking a target quasi-sinusoidal curve of three different amplitudes. Generally speaking, for both static and load-varying isometric contractions, the mean frequency of MMG-EMG cross spectra (MMG-EMG MF) progressively increased with effort level, whereas the median frequency of EMG auto spectra among higher effort levels remained unchanged. The MMG-EMG MF versus EMG root mean square regression slope was significantly larger for load-varying isometric contraction than for static contraction control measurements. These findings highlight effort-dependent and task-specific rate coding for force regulation of the tibialis anterior.
- Published
- 2007
30. An innovative device for elastic resistance training
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H. Fanchiang, I.-S. Hwang, and C. Chen
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Computer science ,business.industry ,Resistance training ,Physical Therapy, Sports Therapy and Rehabilitation ,Structural engineering ,business - Published
- 2015
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31. A simple SVC algorithm incorporated with the DMB video codec
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Kyeong-Hoon Jung, Jun Ki Kim, H. J. Kim, Y. T. Kim, I. S. Hwang, I. K. Park, Dong Wook Kang, and K. D. Kim
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Digital image ,Motion field ,Computer science ,Image quality ,Motion estimation ,Real-time computing ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Codec ,Image processing ,Algorithm ,Encoder ,Scalable Video Coding - Abstract
We propose a very simple scalable video coding (SVC) system based on the H.264 baseline profile codec. The proposed SVC algorithm can offer three levels of the temporal and spatial scalability - QVGA@15fps, QVGA@30fps, and VGA@30fps. The proposed system achieves the temporal scalability by encoding every other picture as the non-reference P-picture, so that the base layer codec dealing with the QVGA@15fps sequence is fully-compatible with the satellite-digital multimedia broadcasting (S-DMB) system in Korea. In addition, the same decoder can reconstruct the QVGA@30fps sequence when it receives the bits representing the non-reference pictures. For the spatial enhancement layer, the encoder follows the standard H.264 baseline profile except the inter-layer intra prediction. To reduce the computational burden of the encoder, the enhancement layer encoder may skip the motion estimation procedure by interpolating the motion field with that of the base layer. Simulation results show that the proposed system yields less then about 12% of loss in the reconstruction picture quality compared with the anchor H.264 JM encoder. The proposed SVC system still has a room for improvement of coding efficiency by trading with the computational complexity, so that lots of further works are required.
- Published
- 2006
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32. The effects of weight load and joint immobilization on reorganization of postural tremor
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I S, Hwang, C C, Huang, J H, Sul, C T, Huang, C H, Wang, and M S, Young
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Adult ,Male ,Restraint, Physical ,Weight-Bearing ,Wrist Joint ,Adolescent ,Splints ,Electromyography ,Posture ,Tremor ,Humans ,Female ,Muscle, Skeletal - Abstract
To investigate change in coordinative strategies due to wrist immobilization and index loading, postural tremors from the index, hand, and forearm were recorded during different postural holding tasks. The wrist joint was immobilized with a thermoplastic splint in the constrained condition, and a copper mass of 100 grams was applied to the index finger in the loaded condition. The structures of the postural tremors of all upper limb segments among the unloaded-unconstrained, unloaded-constrained, loaded-unconstrained, and loaded-constrained conditions were compared. Index loading exaggerated index/forearm postural tremor, while the load-induced tremor enhancement was no longer evident for wrist immobilization. In the unloaded condition, wrist immobilization resulted specifically in enhancement of carpal postural tremor, rather than in the index and forearm. Index loading induced a marked tremor peak and relative power in the range of 5-8 Hz. Wrist immobilization potentiated the carpal tremor peak of 1-4 Hz in association with enhancement of carpal-forearm mechanical coupling. In light of structural changes in postural tremor, our data suggest that (1) a wrist splint is effective to counteract load-induced enhancement of postural tremor, and (2) freezing of the wrist joint might facilitate compensatory strategies to minimize passive fluctuation transmission from the carpal to index.
- Published
- 2006
33. Nitrogen removal from piggery waste using the combined SHARON and ANAMMOX process
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I S, Hwang, K S, Min, E, Choi, and Z, Yun
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Nitrates ,Time Factors ,Base Sequence ,Nitrogen ,Swine ,Industrial Waste ,Nucleic Acid Hybridization ,Hydrogen-Ion Concentration ,Waste Disposal, Fluid ,Aerobiosis ,Carbon ,Manure ,Quaternary Ammonium Compounds ,Bioreactors ,Ammonia ,Animals ,Oligonucleotide Probes ,Oxidation-Reduction ,Nitrites - Abstract
Nitrogen removal in piggery waste was investigated with the combined SHARON-ANAMMOX process. The piggery waste was characterized as strong nitrogenous wastewater with very low C/N ratio. For the preceding SHARON reactor, ammonium nitrogen loading and conversion rates were 0.97 kg NH4-N/m3 reactor/day and 0.73 kg NH4-N/m3 reactor/day, respectively. Alkalinity consumption for ammonium conversion was 8.5 gr bicarbonate utilized per gram ammonium nitrogen converted to NO2-N or NO3-N at steady-states operation. The successive ANAMMOX reactor was fed with the effluent from SHARON reactor. Nitrogen loading and conversion rates were 1.36 kg soluble N/m3 reactor/day and 0.72 kg soluble N/m3 reactor/day, respectively. The average NO2-N/NH4-N removal ratio by ANAMMOX reaction was 2.13. It has been observed that Candidatus "Kuenenia stuttgartiensis" were dominated in the ANAMMOX reactor based on FISH analysis.
- Published
- 2006
34. Muscle control associated with isometric contraction in different joint positions
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I S, Hwang and C Y, Cho
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Adult ,Male ,Motor Neurons ,Recruitment, Neurophysiological ,Electromyography ,Physical Exertion ,Posture ,Weight-Bearing ,Reference Values ,Isometric Contraction ,Humans ,Female ,Muscle, Skeletal ,Ankle Joint - Abstract
The purpose of this study was to investigate the dependence of the surface EMG and varied internal effort due to different joint positions, and its muscle control strategies. Ten healthy subjects performed a fixed level (40% MVC measured in the neutral position) of isometric dorsiflexion and plantarflexion contraction in the ankle neutral, dorsiflexion, and plantarflexion positions. Quantitative EMG analyses with feature extraction in the time, frequency domain, as well as time-varying spectrum were employed to estimate recruitment pattern, code rating, and recruitment stationarity of activated motor units. Both RMS and median frequency of the tibial anterior (TA) and gastrocnemius (GS) were strongly dependent on foot position (p.001). Dominant firing rate of the TA muscle during the effort related isometric contraction was significant different with respect to ankle position (p.05). Irrespective of ankle position, the regression slope of median frequency across time was not different from zero for both TA and GS muscles (p.05). Identical torque exertion in different ankle positions called for considerable changes of control strategies of motor units. Possible mechanisms could be augmented excitatory central afferents and release of inhibition from Golgi tendon organs in compensation for biomechanical disadvantage in shorter muscle length.
- Published
- 2005
35. Single-atom Tip as an Emitter of Gas Field Ion Source
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W.-T. Chang, C.-Y. Lin, Tien T. Tsong, I.-S. Hwang, T.-Y. Fu, J.-L. Hou, and H.-S. Kuo
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Materials science ,Atom (order theory) ,Atomic physics ,Instrumentation ,Ion source ,Common emitter - Abstract
Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.
- Published
- 2013
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36. ANAMMOX and partial denitritation in anaerobic nitrogen removal from piggery waste
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Y H, Ahn, I S, Hwang, and K S, Min
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Manure ,Quaternary Ammonium Compounds ,Bacteria, Anaerobic ,Bioreactors ,Nitrates ,Nitrogen ,Swine ,Animals ,Oxidation-Reduction ,Waste Disposal, Fluid - Abstract
The anaerobic ammonium removal from a piggery waste with high strength (56 g COD/L and 5 g T-N/L) was investigated using a lab-scale upflow anaerobic sludge bed reactor at a mesophilic condition. Based on the nitrogen and carbon balance in the process, the contribution of autotrophic and heterotrophic organisms was also evaluated in terms of the influent NO2-N/NH4-N ratio (1:0.8 and 1:1.2 for Phase 1 and Phase 2, respectively). The result of this research demonstrates that the anaerobic ammonium removal from the piggery waste, using the UASB reactor, can be performed successfully. Furthermore, it appears that by using granular sludge as the seed biomass, the ANAMMOX reaction can start more quickly. Average nitrogen conversion was 0.59 kg T-N/m3 reactor-day (0.06 kg T-N/kg VSS/day) and 0.66 kg T-N/m3 reactor-day (0.08 kg T-N/kg VSS/day) for Phase 1 and Phase 2. The NO2-N/NH4-N removal ratio by the ANAMMOX was 1.48 and 1.79 for Phase 1 and Phase 2. The higher nitrite contents (about 50%) in the substrate resulted in higher nitrite nitrogen removal by the partial denitritation, as well as the ANAMMOX reaction, implying higher potential of partial denitritation. However, the result reveals that the ANAMMOX reaction was influenced less by the degree of partial denitritation, and the ANAMMOX bacteria did not compete with denitritation bacteria. The colour of the biomass at the bottom of the reactor changed from dark gray to dark red, which was accompanied by an increase in cytochrome content. At the end of the experiment, red-coloured granular sludge with diameter of 1-2 mm at the lower part of the reactor was also observed.
- Published
- 2004
37. US conductor R&D and small scale experiments for the ITER magnets
- Author
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M.A. Ferri, M.K. Ahmed, A.E. Long, Changheui Jang, Sangkwon Jeong, Ronald G. Ballinger, W.C. Guss, R.N. Randall, C.Y. Gung, D.B. Montgomery, L. S. Toma, D. Reisner, Makoto Takayasu, I. S. Hwang, M. M. Morra, Joseph Minervini, S. Johnson, M. M. Steeves, C.A. Hall, and T.M. Hrycaj
- Subjects
Superconductivity ,Engineering ,Fabrication ,Scale (ratio) ,business.industry ,Magnet ,Mechanical engineering ,Superconducting magnet ,Fusion power ,business ,Engineering design process ,Conductor - Abstract
During the Engineering Design Activity (EDA) of the ITER program a major effort is being devoted to conductor R&D for the ITER magnets systems. This program includes all aspects of cable-in-conduit-conductor (CICC) manufacturing development such as superconducting strand, large multistage cables, and fabrication of thick-wall and thin-wall conduits. It also includes an extensive program of small scale laboratory measurements and experiments designed to predict the full-size conductor and magnet performance, and to quantify elements of the conductor design guidelines. A description of the manufacturing development and experimental program is given, including experiments for determining AC losses in the superconductor, CICC stability under BC and fast ramped conditions of field and current, and development of novel quench detection techniques.
- Published
- 2002
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38. Inter-trial variation of soleus H reflex in humans: implication for supraspinal influence
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I S, Hwang and I Y, Tsai
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Adult ,Motor Neurons ,Time Factors ,Adolescent ,Electromyography ,Genetic Variation ,Electric Stimulation ,Spine ,H-Reflex ,Reference Values ,Reaction Time ,Humans ,Muscle, Skeletal ,Muscle Contraction - Abstract
Inter-trial variation in soleus H reflex amplitude for different effort modes, elicited at different test-stimulus intensities, was studied in fifteen healthy subjects. Regardless of test-stimulus intensity, weak isometric plantarflexion and dorsiflexion at 20% of maximum voluntary contraction caused significant potentiation and depression of the H reflex amplitude. In addition, both facilitation and inhibition of the soleus H reflex was associated with considerable inter-trial variability of the H reflex amplitude that varied proportionally with test-stimulus intensity. As inter-variability of the H reflex was independent of that of M response, the results indicate that: 1) supra-spinal input influences loop-gain fluctuations of the monosynaptic-reflex arc; and 2) smaller test stimuli may be more efficacious for exploration of motoneuronal excitability because of reduction in variability in H reflex amplitude.
- Published
- 2002
39. Nondissociative adsorption ofO2on theSi(111)−7×7surface
- Author
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I. S. Hwang, Y.-H. Tang, Tien T. Tsong, and M.-H. Tsai
- Subjects
Surface (mathematics) ,Adsorption ,Materials science ,Chemical engineering - Published
- 2002
- Full Text
- View/download PDF
40. Investigation of sulfhydryl groups in cabbage phospholipase D by combination of derivatization methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
- Author
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I S, Hwang, S J, Park, T, Roh, M, Choi, and H J, Kim
- Subjects
DNA, Complementary ,Ethylmaleimide ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,p-Chloromercuribenzoic Acid ,Phospholipase D ,Trypsin ,Brassica ,Cysteine ,Iodoacetic Acid - Abstract
All eight cysteine residues in 92 kDa cabbage phospholipase D (PLD), deduced from the cDNA sequence, were shown to have free sulfhydryl groups by analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of tryptic peptides of PLD derivatized with p-chloromercurybenzoate, iodoacetic acid, and N-ethylmaleimide, as well as of underivatized PLD. Assignment of sulfhydryl groups by any one method was not conclusive. However, complementary information derived from tryptic peptides derivatized with different reagents made full assignment of sulfhydryl groups possible.
- Published
- 2001
41. Applications of Robotics to Assessment and Physical Therapy of Upper Limbs of Stroke Patients
- Author
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M.-S. Ju, C.-C. K. Lin, S.-M. Chen, I.-S. Hwang, P.-C. Kung, Z.-W. Wu, M.-S. Ju, C.-C. K. Lin, S.-M. Chen, I.-S. Hwang, P.-C. Kung, and Z.-W. Wu
- Published
- 2007
- Full Text
- View/download PDF
42. Conceptual Design Analysis of 4K Irradiation Facility in Korean Hanaro Research Reactor
- Author
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I. S. Hwang, H. M. Chang, W. S. Park, G. W. Hong, and B. J. Jun
- Subjects
Nuclear physics ,Thermonuclear fusion ,Materials science ,Neutron flux ,law ,Magnet ,Neutron source ,Research reactor ,Superconducting magnet ,Irradiation ,Nuclear reactor ,law.invention - Abstract
A conceptual design of a 4 K irradiation test facility has been conducted in support of the International Thermonuclear Experimental Reactor (ITER) magnet development program. A new research reactor designated as HANARO at the Korea Atomic Energy Research Institute has a Cold Neutron Source (CNS) port that is identified to be suitable for the fast neutron irradiation of metals and insulation materials for superconducting magnets at 4 K. A 40 hours of irradiation at full power will produce 2.5×1017 n/cm2 of the ITER magnet design neutron fluence with energy above 0.1 MeV. A material testing laboratory of Irradiated Materials Evaluation Facility (IMEF) that is located next to HANARO has been equipped with 77 K test machines and fracture analysis microscopes for radioactive specimens which can be upgraded for 4 K test without any intermediate warming. CNS radiation spectrum determined by Monte Carlo method is found to be more favorable for metal irradiation than for insulation materials with absorbed gamma dose that is 7–10 times the fast neutron dose. A lead-shielded irradiation capsule design with a 1 cm diameter specimen in 3 cm cold-bore diameter and 18 cm height will require about 120 watt cooling capacity at 4.6 K.
- Published
- 1996
- Full Text
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43. Electromyographic analysis of habituation processes of treadmill walking to floor walking
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I S, Hwang, J J, Chen, J J, Liou, T C, Huseh, and Y L, Chou
- Subjects
Adult ,Male ,Electromyography ,Exercise Test ,Humans ,Habituation, Psychophysiologic ,Gait - Abstract
Electromyography (EMG) is an essential tool for assessing muscle performance in human locomotion. The aim of this research is to utilize EMG for assessing the habituation processes of normal adults during treadmill walking compared to floor walking. In this research, EMG activity is presented in linear envelope (LE) form to meet physiological meanings and parameter estimation. The EMG LE is generated from the raw EMG signal through band-pass filtering, rectifying, integration, and normalization procedures. The ensemble averaging of EMG LEs is used to demonstrate the pooled data of six normal subjects. The variance ratio (VR) of the EMG LE is applied to analyze the repeatability of EMG activity and thus to quantify the habituation process of normal adults walking on a treadmill. The habituation results indicated that no pretibial group reached a steady state during 12 minutes of treadmill walking. However the majority of calf groups habituated after 2 minutes of treadmill walking. In addition, changes in EMG phasic activities could be observed for both pretibial and calf groups during treadmill walking.
- Published
- 1994
44. Development of a High Toughness Weld for Incoloy Alloy 908
- Author
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M. M. Steeves, Ronald G. Ballinger, I. S. Hwang, and Changheui Jang
- Subjects
Toughness ,Materials science ,Alloy ,Metallurgy ,Welding ,Superconducting magnet ,engineering.material ,Thermal expansion ,law.invention ,Superalloy ,Fracture toughness ,law ,engineering ,Incoloy - Abstract
Incoloy® alloy 908+ is a candidate conduit material for the large-scale Nb3Sn superconducting magnets of the International Thermonuclear Experimental Reactor (ITER).1 It is a nickel-iron base precipitation-hardening superalloy with a chemical composition that has been optimized for a low coefficient of thermal expansion, superior cryogenic structural properties, and phase stability during the Nb3Sn reaction heat treatment.2 The alloy precipitates γ′, Ni3(A1,Ti,Nb), as the primary strengthening phase and has demonstrated excellent mechanical properties at both 298 and 4 K.3,4 However, welds of the alloy have shown reduced fracture toughness. Since fabrication of the cablein-conduit conductors for ITER will require welding, the motive of the work has been to improve fracture toughness while maintaining adequate weld strength.
- Published
- 1994
- Full Text
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45. Fatigue Crack Thresholds of a Nickel-Iron Alloy for Superconductor Sheaths at 4 K
- Author
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R. L. Tobler and I. S. Hwang
- Subjects
Superconductivity ,Reproducibility ,Materials science ,Alloy ,chemistry.chemical_element ,Thermal treatment ,Superconducting magnet ,Paris' law ,engineering.material ,Superalloy ,Nickel ,chemistry ,engineering ,Composite material - Abstract
Short crack simulation (SCS) tests were used to characterize the fatigue crack growth rates da/dN and thresholds ΔKTh of a Ni-Fe superalloy proposed for conduit sheath applications in superconducting magnets at 4 K. Experiments described demonstrate the reproducibility of the SCS data and confirm that this alloy has a relatively high fatigue crack growth rate threshold at 4 K. The effects of plate thickness and thermal treatment (650°C, 180 h) on near-threshold fatigue properties are minor compared with a strong cryogenic temperature effect that increases the fatigue threshold from about 2 MPa·m1/2 at room temperature to 9 or 10 MPa·m1/2 at 4 K.
- Published
- 1994
- Full Text
- View/download PDF
46. Stress Accelerated Grain Boundary Oxidation of Incoloy Alloy 908 in High Temperature Oxygenous Atmospheres
- Author
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L. S. Toma, M. M. Steeves, I. S. Hwang, M. M. Morra, S. Nicol, and Ronald G. Ballinger
- Subjects
Controlled atmosphere ,Materials science ,Argon ,chemistry ,Metallurgy ,chemistry.chemical_element ,Limiting oxygen concentration ,Intergranular corrosion ,Inert gas ,Embrittlement ,Oxygen ,Incoloy - Abstract
Heat treatments of magnets utilizing INCOLOY® alloy 908* as a conduit have been successfully performed in vacuum. Similar experience with large scale heat treatment in an inert gas environment such as argon is lacking. Prior studies on other nickel-iron base superalloys that are susceptible to intergranular oxygen embrittlement and cracking emphasize the importance of establishing an allowable oxygen impurity level in argon for alloy 908. Initial screening using C-ring tests have shown that cracking can occur in an argon atmosphere if proper control over the oxygen impurity level is not maintained. Stress-rupture tests performed in air show that this material is susceptible to intergranular cracking in notched sections when subjected to stresses in excess of 300 MPa for a stress-concentration factor (Kt) of 4.1 at the notch. A series of stress-rupture tests are now underway on alloy 908 base metal in oxygen containing argon atmospheres. A double-edged notched test specimen design is used to determine the rupture time as functions of applied stress, temperature and oxygen concentration. The oxygen concentration at the specimen notches is continuously measured using an electrochemical sensor. Initial results suggest that an argon atmosphere does yield an improved stress-rupture life over air at low oxygen concentrations. Results are discussed to establish whether the possibility for heat treatments in argon exists and if so what guidelines must be used for successful heat treatment.
- Published
- 1994
- Full Text
- View/download PDF
47. Thermomechanical Process Effects on Hardness and Grain Size in Incoloy® Alloy 908
- Author
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R.N. Randall, I. S. Hwang, M. M. Steeves, and L. S. Toma
- Subjects
Superalloy ,Superconductivity ,Materials science ,Magnet ,Alloy ,engineering ,Thermomechanical processing ,engineering.material ,Composite material ,Critical field ,Grain size ,Incoloy - Abstract
The relationship between thermomechanical processing, hardness, grain size and mechanical properties has been studied for INCOLOY® alloy 908, a nickel-iron base superalloy developed for use as a conduit material in Nb3Sn cable-in-conduit conductors (CICC).1 The alloy has thermal coefficient of expansion properties tailored for Nb3Sn, minimizing compressive strain in the superconductor due to cooldown and the associated reduction in critical properties (upper critical field, critical temperature, and critical current). Alloy 908 also has mechanical properties at cryogenic temperatures that compare favorably with other materials. It is therefore one of the candidate materials for use in the magnets of the International Thermonuclear Experimental Reactor (ITER).2,3
- Published
- 1994
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- View/download PDF
48. 330 REDUCED HYPERACUTE REJECTION BY TRIPLE TRANSGENIC EXPRESSION OF HUMAN COMPLEMENT REGULATORY FACTORS (hDAF and hCD59) AND H-TRANSFERASE
- Author
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Y. H. Jeong, E.-B. Jeung, Sang-Hwan Hyun, C. H. Park, T. Shin, Y. W. Kim, W. S. Hwang, G. H. Jang, I. S. Hwang, H. J. Lee, and Y. W. Jeong
- Subjects
Expression vector ,Transgene ,Xenotransplantation ,medicine.medical_treatment ,Electroporation ,Cell ,Reproductive technology ,Biology ,Molecular biology ,Cytolysis ,Endocrinology ,medicine.anatomical_structure ,Reproductive Medicine ,Cell culture ,Immunology ,Genetics ,medicine ,Animal Science and Zoology ,Molecular Biology ,Developmental Biology ,Biotechnology - Abstract
The present study was conducted to establish a porcine transgenic cell line with human CRPs and HT genes, focused on hyperacute rejection (HAR) considering clinical xenotransplantation as alternative sources of human organs. As a first step towards establishing the stable cell line, the cDNA for 3 genes encoding human DAF, CD59, and H-transferase were cloned and sequenced. A tricistronic expression vector was constructed with the aid of 2 IRES elements (pCMV-hDAF_IRES-hHT_IRES-hCD59). The CMV-based expression vector was then introduced into miniature pig ear fibroblast cells by electroporation. Reverse transcription PCR analysis revealed that cell lines stably expressing human transgene-specific transcripts were established. The inhibitory effect of immune response in the established transgenic cell lines was measured by human serum-mediated cytolysis assay, as measured by ELISA. Under the assay conditions (based on human serum from 10 to 50%), the transgenic cell group showed significantly greater survival rate under various serum concentrations than did the nontransgenic cell control group. Moreover, the transgenic cell lines used as nuclear donors for a subsequent NT experiment were confirmed to be expressing their transgene transcripts in vitro developed preimplantation stage embryos. These results indicated that the established cell lines with human transgenes might have an inhibitory effect against lysis by human complement. It is possible that these transgenic cells could serve as nuclear donors to produce transgenic cloned pigs for xenotransplantation.
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- 2011
- Full Text
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49. 282 IDENTIFICATION OF SRY AND STEROIDOGENIC FACTOR-1 (SF1) GENES IN CANINE XY MALE-TO-FEMALE SEX DEVELOPMENTAL DISORDER
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Y. H. Jeong, I. S. Hwang, G. H. Jang, Y. W. Kim, T. Shin, Y. W. Jeong, W. S. Hwang, Sang-Hwan Hyun, and E.-B. Jeung
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Genetics ,Mutation ,Male sex determination ,Abnormal sex determination ,Reproductive technology ,Gene mutation ,Sex reversal ,Biology ,medicine.disease_cause ,Endocrinology ,Testis determining factor ,Reproductive Medicine ,medicine ,Animal Science and Zoology ,Molecular Biology ,Gene ,Developmental Biology ,Biotechnology - Abstract
Cloning by the process of somatic cell nuclear transfer (SCNT) has been achieved in a variety of mammalian species and has many promising applications. In this process, however, due to reasons beyond current scientific understanding, many results contrary to expectation have also been produced. For instance, abnormal sex development such as demasculinization has been observed in 1 of 6 healthy German shepherd offspring produced with SCNT (1 normal donor (not cloned), 5 cloned but normally developed progenies, 1 cloned sex reversed progeny, and 1 recloned sex reversed progeny from 1 cloned sex reversed progeny). Sex-determining region Y (SRY) is one of the most basic and crucial genes that initiate male sex determination in many mammals. Steroidogenic factor-1 (SF1, NR5A1), which is closely related to SRY, also regulates several genes involved in sex determination. Numerous studies have reported that reduced or deleted SRY gene expression as well as SF1 gene mutations can produced XY sex reversal. To verify the hypothetical association between phenotypic disorder of sex determination and genetic modification by SCNT, we extracted genomic DNA from tissues of normal progeny (not cloned), primary cultured cells of cloned but normally developed progeny, cloned sex reversed progeny, and recloned sex reversed progeny at the age of 1 year and carried out PCR with produced primers based on available SRY and SF1 gene information (SRY gene from AF107021 in GenBank; SF1 gene from ENSCAFG00000023086 in Ensembl). The cloned PCR products were subcloned into T-vector for sequence analysis, which showed no mutation in genetic sequences of SRY and SF1. Taken together, in our case of abnormal sex determination, there was no apparent association between phenotypic sex determination disorder and SRY/SF1 gene mutation. Other sex reversal and related mutation studies have pointed to a wide range of signal networks that include Sox9 and so forth. Further studies should be focused on these other genes in the signal network.
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- 2011
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50. Incoloy 908 database report: On process -- structure -- property relationship
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L.S. Toma, M.M. Steeves, and I. S. Hwang
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Superalloy ,Materials science ,Annealing (metallurgy) ,Ultimate tensile strength ,Metallurgy ,Superconducting magnet ,Microstructure ,Indentation hardness ,Thermal expansion ,Incoloy - Abstract
Incoloy 908 is a nickel-iron base superalloy with a coefficient of expansion (COE) and mechanical properties that have been optimized for use in Nb{sub 3}Sn superconducting magnets. It has been proposed for use as a conduit material for the International Thermonuclear Experimental Reactor (ITER) magnets. The relationship between manufacturing processes, microstructures and mechanical properties of Incoloy 908 are characterized in support of the magnet fabrication and quality control. This report presents microhardness, microstructure, and yield and ultimate tensile strengths as functions of thermomechanical process variables including heat treatment, annealing and cold work for laboratory prepared Incoloy 908 specimens. Empirical correlations have been developed for the microhardness at room temperature and tensile strength at room temperature and at 4K. These results may be used for manufacturing quality control or for design.
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- 1993
- Full Text
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