S. Y. Chen

Academia Sinica, T’ai-pei, Taipei, Taiwan

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Publications (18)33.75 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Cardiac rehabilitation (CR) after heart transplantation is known to benefit physical capacity in adults, but the advantages of CR on pediatric patients with heart retransplantation remain undetermined. Aim. The purpose of the present study was to report the effect of structured CR for a boy receiving heart transplantations twice. Design. Single case study. Setting. Inpatient and outpatient rehabilitation department Population: A pediatric patient underwent heart transplantation due to dilated cardiomyopathy at 13.6 year-old and retransplantation owing to severe cardiac allograft vasculopathy at 16.2 year-old. Methods: CR was arranged after both transplantations. Bicycle or treadmill exercises were conducted three times weekly with the intensity adjusted to the ventilatory threshold. Serial cardiopulmonary exercise tests were performed to evaluate the sequential cardiorespiratory function changes using the peak oxygen uptake ( ·VO2peak) as the primary outcome. Results: The patient had undergone 10 times of exercise tests during rehabilitation. The ·VO2peak increased from 12.27 to 15.63 mL·kg-1·min-1 within 6 months after the primary transplantation. However, the ·VO2peak dropped intensively after a rejection episode and failed to improve since the development of cardiac allograft vasculopathy. Following retransplantation, the ·VO2peak appeared worse initially but increased gradually with rehabilitation. One year subsequent to retransplantation, the ·VO2peak reached 17.7 mL·kg-1·min-1 with a 7.22 mL·kg-1·min-1 improvement compared with his baseline value. Conclusion: Structured CR improves aerobic capacity of a pediatric patient with heart retransplantation. Clinical Rehabilitation Impact. CR is safe and beneficial for pediatrics with heart retransplantation. Cardiopulmonary exercise testing can be considered as an adjuvant tool for detecting rejection or cardiac allograft vasculopathy in pediatric heart transplantation recipients.
    European journal of physical and rehabilitation medicine 03/2013; · 1.95 Impact Factor
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    ABSTRACT: The microstructure and magnetic properties of multilayer [Os(t)/FePt(x)]n films on a glass substrate with a 10 nm Os buffer layer by ion beam sputtering have been studied as a function of the annealing temperatures between 300 and 800 degrees C. Here, t = 0.2, 1 or 5 nm and x varied from 10, 20, 25, 50, to 100 nm with its associated n value of 10, 5, 4, 2, and 1, respectively. No diffusion evidence was found in samples with a thin Os layer and t > or = 1 nm. The average grain size of the multilayer films can be well controlled by both annealing temperature and thickness of the FePt layer by a very thin Os space layer with t > or = 1 nm. The enhancement of H(c) can be understood from the fact that for a FePt film with an Os spacer layers, the increasing number of Os layer will inhibit the grain growth of FePt grains and enriches the grain boundary. We have experimentally demonstrated that even with a very thin 1 nm Os spacer layers, the [Os(t)/FePt(x)]n multilayer films can exhibit good hard magnetic properties and are attractive candidates for ultrahigh density magnetic recording media.
    Journal of Nanoscience and Nanotechnology 12/2011; 11(12):11133-7. · 1.34 Impact Factor
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    ABSTRACT: The microstructure, ordering parameter, and magnetic properties of multilayer [FePt(x)/Os]n films on glass substrate by dc-magnetron sputtering (with x being thickness in nm; Os with a fixed thickness 5 nm; n being the number of layers) have been studied as a function of the annealing temperatures between 300 and 900 °C. The grain size of multilayer films can be controlled by annealing temperature and thickness of the FePt layer with Os space layer. The coercivity as a function of the annealing temperature for samples with n = 1 and pure FePt behaves roughly saturated after annealing above 700 °C. However, for samples with n > 4 the value of Hc seems still increasing with increasing annealing temperature between 600 and 900 °C, and the ordering parameter decreases with increasing the number of Os layers. Our experimental results are reasonably well to describe the effect of strain-assisted transformation.
    Journal of Applied Physics 01/2011; 109. · 2.19 Impact Factor
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    ABSTRACT: By making use of the dc magnetron sputtering system, the Au/FePt bilayers have been prepared on glass substrates and anodized aluminum oxide (AAO) membranes with an average pore diameter of around 200 nm. In both cases, the FePt films can be converted into the magnetically hard phase, namely L10 phase, after a heat treatment above 500 °C for 1 h. A nanoparticle-like structure can be observed in the 15-nm-thick FePt film on the AAO membrane. The experimental observations of the structure and the magnetism of the FePt films on the AAO membranes are firstly established.
    Vacuum 06/2010; 84(12):1435-1438. · 1.43 Impact Factor
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    ABSTRACT: The thermal stability, interlayer diffusion, and magnetic properties of FePt(100 nm) single-layer and multilayer [Os(5 nm)/FePt(25 nm)]4 films on a Si(100) substrate with/without a 10-nm-thick Os underlayer have been studied as functions of the annealing temperatures between 400 and 800 °C. The insertion of a thin Os layer into the FePt and Si(100) interface results in better thermal stability. No diffusion evidence was found in samples with an Os underlayer for annealing temperatures up to 700 °C, as seen from x-ray, transmission electron microscopy, and magnetic studies. We have experimentally demonstrated that the Os underlayer can effectively prevent the diffusion of the intermixing between the FePt layer and the Si(100) substrate for temperatures up to 700 °C. As a result of this study, the Os has potential to be a better diffusion barrier to prevent the diffusion of the FePt film on a Si(100) substrate from forming an ordered face centered tetragonal (fct) L10 hard magnetic phase.
    Journal of Applied Physics 01/2010; 107. · 2.19 Impact Factor
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    ABSTRACT: Bi-stable switching effect has been studied in nickel oxide films with three different thicknesses. The best sample of our experiments was 150-nm NiO film. Its resistance ratio between high and low states was 3.6 in endurance measurement. The maximum resistance ratio in I–V curve could reach two orders of magnitude, and it could endure over 200 times of reverse processes with the ratio remaining about 1.46. This indicates that the nickel oxide has potential to be a promising material on resistance random access memory.
    Journal of Magnetism and Magnetic Materials 03/2007; 310(2). · 2.00 Impact Factor
  • S.Y. Chen, Y.D. Yao, J.M. Wu
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    ABSTRACT: Effects of the Os layer on the magnetic properties of FePt/Os/FePt were investigated. The magnetic layer of FePt in the as-deposited Ta/FePt/Os/FePt/Ta thin films exhibited very strong (1 1 1) orientation in all the cases. As the thickness of Os spacer layer between 1 and 3 Å, it appeared an antiferromagnetic exchange coupling (AFC) behavior. The exchange coupling transforms to ferromagnetic when the thickness of Os spacer layer was thicker than 4 Å. Although the J value for FePt/Os/FePt thin films is −0.22 erg/cm2, which is relatively small than that of Co/Ru system, the GMR effects could be observed. In general, the AFC in multilayer system shows the first maximum of AFC peak occurring at spacer thickness between 8 and 11 Å for most spacer materials. In our investigation, this is the first time that a clear AFC behavior observed in FePt/Os/FePt system with Os spacer thickness at 2 Å.
    Journal of Magnetism and Magnetic Materials 03/2007; 310(2):1914-1916. · 2.00 Impact Factor
  • S.Y. Chen, Y.D. Yao, J.M. Wu
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    ABSTRACT: The CoFe/Os/CoFe thin films were deposited on natural oxidized Si(1 0 0) substrates at room temperature by an ultra-high vacuum DC-magnetron sputtering system with a base pressure less than 1×10−8 Torr. The thickness of the ferromagnetic layers was 100 Å in all cases and a series of trilayers with Os spacer ranging from 3 to 20 Å was made. Effects of the Os layer thickness on the magnetoresistance (MR) and magnetic properties were investigated. The results showed that the magnetism switched from ferromagnetic (Os thickness=3, 5 Å) to antiferromagnetic (Os thickness=7–13 Å) and then ferromagnetic (Os thickness=20 Å) again. From the MR study, we see that the AMR ratio decreased from 4.64% to the minimum value 0.69% at 9 Å and then increased; GMR ratio increased from 0.01% to the maximum value 0.43% at 9 Å and then decreased. From the hysteresis loops, the results exhibited that coercivity increased from 16 Oe to the maximum value 92 Oe at 9 Å and then decreased, and squareness value decreased from 0.97 to the minimum value 0.17 at 9 Å and then increased. Dependence of saturation field on Os spacer-layer thickness for CoFe trilayers showed a maximum value 216 Oe at 9 Å. This suggests that the small GMR effect may be related to the small exchange coupling strength in CoFe/Os/CoFe thin films.
    Journal of Magnetism and Magnetic Materials 09/2006; · 2.00 Impact Factor
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    ABSTRACT: MgO(0 0 1) has been growing successfully on Fe/Pd/Cu/Si(1 0 0) by e-beam evaporation as examined by X-ray diffraction and high resolution transmission microscope. We present the magnetic peculiarity of crystal structure Fe(0 0 1)/Pd(0 0 1)/Cu(0 0 1) on Si(0 0 1) substrate. The magnetic properties of the sample were measured by magneto-optical Kerr effect which shows an in-plane magnetocrystalline anisotropy.
    Journal of Magnetism and Magnetic Materials 09/2006; 304(1):e44–e46. · 2.00 Impact Factor
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    ABSTRACT: The magnetoimpedance (MZ) effect of the pseudo-spin-valve transistor (PSVT) was investigated at room temperature in the frequency ranged from 100 Hz to 15 MHz . The PSVT can be regarded as a complex combination of resistors, inductors, and capacitors, while the impedance (Z) consists of a real part, the resistance (R) , and an imaginary part, the reactance (X) . Besides, all these components exhibit magnetic hysteresis. It is due to the frequency dependent behavior that R does not reach a minimum at the resonant frequency (f<sub>r</sub>) . The frequency dependences of MZ and MX ratios cross zero at f<sub>x</sub>=6.5 MHz and at f<sub>r</sub>=3.65 MHz , respectively. The shape of magnetoreactance (MX) loop is reverse to the magnetoresistance (MR) loop; furthermore, MX ratio changes sign from negative at f≪f<sub>r</sub> to positive at f≫f<sub>r</sub> . The MZ loop also reverses shape and sign after crossing f<sub>x</sub> . For instance, the MZ loop with a ratio of 0.077% at 6 MHz switches to -0.086% and -0.125% at 7 and 8 MHz , respectively.
    Journal of Applied Physics 05/2006; · 2.19 Impact Factor
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    ABSTRACT: A simple structure of Ta/CoFe/Os(d)/OsMn is deposited by HV sputtering system, where d varies from 0 to 2 nm. After deposition, all samples are subjected to magnetic field annealing at 1 kOe and at different temperatures for 30 minutes. No diffusion evidence is found from the Auger electron spectroscopy depth profile and magneto-optical Kerr effect measurements for samples with d=1 and 2 nm annealed below 300°C. This result suggests that the inserted osmium layer prevents Mn diffusion into the magnetic CoFe layer.
    01/2005;
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    ABSTRACT: The crystallization structure and thickness of PtMn layer in a magnetic tunnel junction system are important factors to improve its exchange bias effect. This study shows that the PtMn layer could be changed from a FCC (111) structure to a FCT (111) structure after annealing above 270 °C. The minimum thickness of PtMn layer is found to be 10 nm for exchange coupling effect to be occurred in our MTJ system. The magnetic exchange effect between PtMn and SAF layers is near 4,300 Oe. Annealing temperatures can be higher than 400 °C for samples without patterning; however, temperature at 275 °C is too high for samples after patterning. This may be due to the breakdown of edges of the patterned samples as well as the complicated environments around the patterned samples. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    physica status solidi (c) 12/2004; 1(12).
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    ABSTRACT: Face-centered-cubic Ag(100) submicrometer islands on an RCA-cleaned Si(100) substrate were fabricated by molecular beam epitaxy; a 500 Å Fe thin film was then grown onto Ag films at 100 °C. We experimentally demonstrate that the magnetic behavior of Fe films is strongly dependent on the thickness and morphology of the Ag underlayer. The Ag film, in order to reduce the surface free energy, forms isolated three-dimensional square islands with {111} sidewall on the Si(100) substrate. The average height, grain size and surface roughness of these Ag islands were tuned by varying the deposition thickness of the Ag film. The in-plane easy axis of the Fe film was rotated 45° while the thickness of the Ag underlayer reaches 100 Å and the Ag rough surface provides a source of domain wall pinning. © 2003 American Institute of Physics.
    Journal of Applied Physics 05/2003; 93(10):7468-7470. · 2.19 Impact Factor
  • Medicine &amp Science in Sports &amp Exercise 01/2003; 35. · 4.46 Impact Factor
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    ABSTRACT: This study aims to describe the national incidence rate and characteristics of lower limb amputations (LLA) in 1997 from an island-wide database of the national health insurance programme in Taiwan. Some 117,647 discharge records from a sampled database (1 in 20) of the National Health Insurance Research Database were analysed. This study included records (n=171) containing LLA procedures. The LLA procedure rates were obtained by multiplying the number of identified procedures by 20 as the numerator and mid-year total population of Taiwan in 1997 as the denominator. Each procedure was further analysed according to the demographic characteristics of the patients, cause and level of amputation. Summarised gender ratios of LLA procedure rates were obtained by Poisson regression analysis. The crude LLA procedure rate was 18.1 per 100,000 population per year and the crude major LLA procedure rate was 8.8 per 100,000 population per year in Taiwan in 1997. The major cause of LLA procedures was peripheral vascular disease (72%), and the toe was most frequently amputated (48%). The LLA procedure rates, which increased logarithmically with age of patients, were significantly higher in men with a summarised male to female rate ratio of 1.65. The age-standardised LLA procedure rate in Taiwan was lower than that reported in the United States, Finland, the Netherlands, the United Kingdom (Leeds, Middlesborough, and Newcastle), but higher than Spain, Italy, and Japan. The trend of an increasing proportion of PVD-related LLA procedures will prompt the health professionals to develop strategies for LLA prevention.
    Prosthetics and Orthotics International 05/2002; 26(1):7-14. · 1.07 Impact Factor
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    ABSTRACT: To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations. Observational, single patient, descriptive. An 80-meter long rectangular hallway in a rehabilitation unit. A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit. The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation. Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge. People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.
    Archives of Physical Medicine and Rehabilitation 03/2001; 82(2):265-9. · 2.44 Impact Factor
  • C Lan, S Y Chen, J S Lai, M K Wong
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    ABSTRACT: Tai Chi Chuan (TCC) is a popular Chinese conditioning exercise, however, its exercise intensity remains controversial. The objective of this study was to determine the exercise intensity of Yang TCC by measuring heart rate (HR) responses and oxygen consumption (VO2) during practice. Fifteen men aged 39.9 +/- 9.5 yrs (range 26-56 yrs) participated in this study. Subjects had practiced classical Yang TCC for 5.8 +/- 2.4 years. HR responses and VO2 were measured during practice of TCC by using a K4 telemetry system. Blood lactate was measured before and immediately after TCC practice. Additionally, breath-by-breath measurement of cardiorespiratory function and sequential determination of blood lactate were performed during the incremental exercise of leg cycling. Measurements obtained during the TCC practice and exercise testing were compared to determine the exercise intensity of TCC. While performing TCC, the mean HR of subjects was 140 +/- 10 bpm, and the mean VO2 was 21.4 +/- 1.5 mL x kg(-1) min(-1). Compared with the data of the exercise test, the HR during practice was 58% of the heart rate range. Meanwhile, the VO2 during TCC practice was 55% of the VO2peak. Additionally, the level of blood lactate immediately after TCC practice was 3.8 mM, which reflected the level of lactate during TCC, approximated the onset of blood lactate accumulation (OBLA). The results demonstrate that TCC is an exercise with moderate intensity, and is aerobic in nature.
    The American Journal of Chinese Medicine 02/2001; 29(3-4):403-10. · 2.63 Impact Factor
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    W C Chie, S Y Chen, K J Chang
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    ABSTRACT: The incidence and mortality of breast cancer in Taiwan have increased rapidly in the past several decades, but the societal impact of deaths and disabilities due to breast cancer has not been assessed. This study estimated the disability-adjusted life years (DALYs) for breast cancer patients during 1994, and compared the results with similar data from other areas of the world. DALYs for breast cancer patients in Taiwan were calculated using the equation developed by Murray and Lopez. The incidence and mortality of breast cancer and the population structure were obtained from national statistics maintained by the Department of Health and the Ministry of the Interior. The age-specific mean survival time for breast cancer patients was estimated using the exponential distribution from incidence-mortality linkage of the incidence file at National Taiwan University Hospital and the National Mortality File maintained by the Department of Health. There were 11,963 years of life lost (YLL) due to breast cancer during 1994, 2677 years lived with disability (YLD), and 14,640 DALYs. The YLL and DALYs per 1000 population (1.17 and 1.44) were in the middle of the world spectrum, while the YLD value per 1000 population (0.26) was closer to those of developed countries. The proportion of DALYs contributed by younger patients (< 45 years) was higher than in developed countries and similar to those in developing countries other than Sub-Saharan Africa. The DALYs per 1000 population of women younger than 45 years of age in Taiwan were also higher than those in India, China, other regions of Asia and Islands, Sub-Saharan Africa, and the Middle Eastern Crescent. The disability portion (YLD) of the DALYs for breast cancer patients in Taiwan was higher than in other regions of the world. Moreover, patients younger than 45 years contributed a higher proportion of DALYs than in developed countries. The DALY value per 1000 population younger than 45 years of age was also higher than in developing countries. These results suggest that health professionals should focus more attention on programs for education, screening, and treatment of younger women.
    Journal of the Formosan Medical Association 02/2001; 100(1):20-5. · 1.70 Impact Factor

Publication Stats

80 Citations
33.75 Total Impact Points

Institutions

  • 2011
    • Academia Sinica
      • Institute of Physics
      T’ai-pei, Taipei, Taiwan
    • Fu Jen Catholic University
      T’ai-pei, Taipei, Taiwan
  • 2006–2010
    • National Tsing Hua University
      • Department of Materials Science and Engineering
      Hsinchu, Taiwan, Taiwan
  • 2004–2007
    • National Chiao Tung University
      • Department of Material Science and Engineering
      Hsin-chu-hsien, Taiwan, Taiwan
  • 2003
    • National Taiwan University of Science and Technology
      • Department of Mechanical Engineering
      Taipei, Taipei, Taiwan
  • 2001–2002
    • National Taiwan University Hospital
      • Department of Surgery
      T’ai-pei, Taipei, Taiwan