Hee Young Kim

Daegu Haany University, Daikyū, Daegu, South Korea

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Publications (149)335.18 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The effects of Nb content and heat treatment temperature on the superelastic properties of Ti–24Zr–(8–12)Nb–2Sn alloys, developed for potential biomedical applications, were investigated by tensile testing. The Ti–24Zr–10Nb–2Sn alloy exhibited excellent superelastic properties: its superelastic recovery strain increased with increasing heat treatment temperature and reached 7%, which is twice that of other Ni-free Ti-base superelastic alloys. This was explained by the evolution of the strong {0 0 1}〈1 1 0〉 recrystallization texture.
    Scripta Materialia 01/2015; 95. · 2.97 Impact Factor
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    ABSTRACT: A new class of Ti–50Zr base biomedical superelastic alloys was developed in this study. The (Ti–Zr)–Mo–Sn alloys exhibited a shape memory effect and superelastic property by adjusting Mo and Sn contents. The (Ti–Zr)–1.5Mo–3Sn alloy revealed the most stable superelasticity among (Ti–Zr)–(1–2)Mo–(2–4)Sn alloys. The superelastic recovery strain showed a strong dependence on heat treatment temperature after cold working in the (Ti–Zr)–1.5Mo–3Sn alloy. The superelastic recovery strain increased as the heat treatment temperature increased although the critical stress for slip decreased. The (Ti–Zr)–1.5Mo–3Sn alloy heat treated at 1073 K exhibited excellent superelastic properties with a large recovery strain as large as 7% which is due to the strong {001}β<110>β recrystallization texture.
    Materials Science and Engineering C 11/2014; · 2.74 Impact Factor
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    ABSTRACT: The temperature dependence of nano-sized lattice modulation (nanodomains) introduced by oxygen atoms and martensitic transformation behavior of the (Ti–23Nb)–1.0O alloy were systematically investigated. Nanodomains in the β phase became unstable at higher temperatures and disappeared >373 K, where time-dependent heating-induced forward transformation (HIFT) was confirmed in the (Ti–23Nb)–1.0O alloy. The thermally activated process of HIFT in the (Ti–23Nb)–1.0O alloy was the diffusion of oxygen atoms in nanodomains. Anomalous temperature dependence of shape memory behavior was also confirmed in the (Ti–23Nb)–1.0O alloy, and its mechanism was successfully explained by the diffusion of oxygen atoms during tensile deformation.
    Acta Materialia 11/2014; 80:317–326. · 3.94 Impact Factor
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    ABSTRACT: Glucagon-like peptide-1 (GLP-1) is an incretin hormone produced by cleavage of proglucagon in intestinal L-cells. In the pancreas, GLP-1 stimulates post-prandial insulin secretion, promotes insulin biosynthesis, and improves insulin sensitivity. Because of its insulinotropic activity, GLP-1 has been considered a good candidate drug for treatment of diabetes mellitus. However, clinical use of GLP-1 has been limited by its short half-life, as a result of rapid degradation by dipeptidyl peptidase-IV (DPP-IV).
    Endocrinology and metabolism (Seoul, Korea). 09/2014; 29(3):320-7.
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    ABSTRACT: Reactive oxygen species (ROS) have been implicated in the development of behavioral sensitization following repeated cocaine exposure. We hypothesized that increased ROS following cocaine exposure would act as signaling molecules in the mesolimbic dopamine (DA) system, which might play an important role in mediating the reinforcing effects of cocaine. The aim of this study was to evaluate cocaine enhancement of brain metabolic activity and the effects of ROS scavengers on cocaine self-administration behavior, cocaine-induced ROS production in the nucleus accumbens (NAc) and cocaine enhancement of DA release in the NAc. Metabolic neural activity monitored by temperature and oxidative stress were increased in NAc following cocaine exposure. Systemic administration of the ROS scavenger N-tert-butyl-α-phenylnitrone (PBN) or 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), either pre- or post-treatment, significantly decreased cocaine self-administration without affecting food intake. Infusion of TEMPOL into the NAc inhibited cocaine self-administration. Increased oxidative stress was found mainly on neurons, but not astrocytes, microglia or oligodendrocytes, in NAc of rats self-administering cocaine. TEMPOL significantly attenuated cocaine-induced enhancement of DA release in the NAc, compared to saline controls. TEMPOL had no effect on the enhancement of DA release produced by the DA transporter inhibitor GBR12909. Taken together, these findings suggest that enhancement of ROS production in NAc neurons contributes to the reinforcing effect of cocaine.
    Addiction Biology 06/2014; · 5.91 Impact Factor
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    ABSTRACT: In the previous study, acupuncture at HT7 has shown to attenuate the self-administration of morphine at a low dose (0.1mg/kg). In this study, it was further investigated whether acupuncture at HT7 could attenuate the morphine self-administration at a high dose (0.5mg/kg) MATERIALS & METHODS: Male Sprague-Dawley rats weighing 270-300g were used. After surgery of catheterization, animals were trained to self-administer morphine solution (0.5mg/kg) using daily 1h session under fixed ratio 1 schedule for 3 weeks. Animals that had shown stable morphine-taking (establish baseline: variation less than 20% of the mean of three consecutive days) were subjected to the acupuncture treatment. Bicuculline and SCH 50911 were used to investigate the possible relation between the effect of acupuncture and the GABA receptor system.
    Neuroscience Letters 06/2014; · 2.06 Impact Factor
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    ABSTRACT: The effect of cold rolling ratio on precipitation behavior of an annealed Ti50Ni15Pd25Cu10 alloy was investigated. The change in the cold rolling ratio noticeably affected the precipitation behavior mainly due to the difference in the density of heterogeneous nucleation sites provided by the deformation induced defects. Higher cold rolling ratios caused an increase in the density of precipitates which subsequently caused a decrease in the martensitic transformation temperatures and shape recovery strain. It was confirmed that the prior cold deformation ratio is an important parameter to control the nanoscale precipitation behavior of Ti2Pd and TiPdCu type precipitates, both in terms of their overall density and distribution.
    Journal of Alloys and Compounds 06/2014; 599:212–218. · 2.73 Impact Factor
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    ABSTRACT: The effect of Pd content on the microstructure and high-temperature shape memory properties of Ti–Ni–Pd–Cu alloys was investigated. The increase in Pd content led to the increase of transformation temperatures. The volume fraction of two types of precipitates (i.e. TiPdCu and Ti2Pd) also increased with increasing Pd content. Although the formation of these precipitates resulted in an increased resistance against the plastic deformation, the amount of recovery strain decreased during thermal cycling tests at various stress levels. By adjusting the heat treatment time, a high transformation temperature and large amount of recovery strain could be achieved while keeping the enough resistance against the plastic deformation.
    Materials Science and Engineering A 04/2014; 602:19–24. · 2.41 Impact Factor
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    ABSTRACT: Tsukuba International Conference on Materials Science (TICMS) was held from 28th August to 6th September, 2013 for the celebration of 40th year anniversary of the University of Tsukuba. The conference was organized by the Division of Materials Science, in cooperation with the Graduate School of Pure and Applied Sciences, and Tsukuba Research Center for Interdisciplinary Materials Science.
    IOP Conference Series Materials Science and Engineering 03/2014; 54(1):011001.
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    ABSTRACT: Primary aldosteronism (PA) is now widely recognized to have a higher prevalence than was once thought. In view of its increasing prevalence, we compared chronological changes in clinical manifestations of PA according to different times of diagnosis. In total, 85 patients diagnosed with PA from January 1986 through March 2012 were reviewed retrospectively, based on their medical records. During two periods-1986 to 2005 and 2006 to 2012-41 and 44 patients, respectively, were diagnosed with PA. We compared the clinical and biological characteristics of PA between these periods. The results demonstrate an increasing trend in the prevalence of idiopathic hyperaldosteronism (IHA; p = 0.19). In the 2006 to 2012 period, patients with PA presented with higher serum potassium levels at the time of diagnosis than in the 1986 to 2005 period (p < 0.0002). Adrenal vein sampling (AVS) was performed mostly in the latter period (82.3%) and the diagnostic accuracy of adrenal computed tomography, compared with AVS, was only 56.2%. About 78.0% versus 86.3% of patients had at least one target organ damage (TOD) in the 1986 to 2005 and 2006 to 2012 periods, respectively (p = 0.39). However, patients with TOD were older and had longer durations of hypertension than patients without, in both periods. PA is becoming more prevalent. There was an increasing tendency for IHA, and more PA patients presented with normokalemia than in the earlier period. Early and accurate diagnosis of PA with AVS and proper treatment should have substantial prognostic value.
    The Korean Journal of Internal Medicine 03/2014; 29(2):217-25.
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    ABSTRACT: The effects of Sn content on the stress hysteresis and superelastic properties of Ti–15Nb–3Mo–(0–1.5)Sn were investigated. The stress hysteresis decreased with increasing Sn content due to the suppression of athermal ω phase formation. The addition of Sn was also very effective at increasing the superelastic recovery strain. Due to the dual effect of Sn, which both decreases the Ms and suppresses the athermal ω phase, the stress for inducing martensitic transformation decreased with increasing Sn content up to 1 at.%, then increased on further addition.
    Scripta Materialia 02/2014; s 72–73:29–32. · 2.97 Impact Factor
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    ABSTRACT: The course of NAFLD (nonalcoholic fatty liver disease) and associated factors in nonobese subjects are not well established. We investigated contributing factors for the development and regression of NAFLD in nonobese Koreans, and whether they would differ from those of obese subjects METHODS: 2,307 adults aged over 18 years participated in this longitudinal observational study. The mean duration of follow-up was 28.7 (± 13.2) months. The participants were divided into two groups according to the baseline BMI (nonobese group: BMI < 25kg/m(2) , obese group: BMI ≥ 25kg/m(2) ). The presence or absence of NAFLD was assessed by abdominal ultrasonography RESULTS: Body weight change was independently associated with both the development and regression of NAFLD in nonobese subjects as well as obese subjects. Among the subjects who developed NAFLD, the amount of weight change was higher in nonobese subjects compared to obese subjects (1.6 ± 3.9% vs 0.6 ± 4.2%, p = 0.022); and among those who showed regression of NAFLD, the amount of weight change was lower in nonobese subjects (-1.9 ± 4.0% vs. -5.0 ± 4.6%, p < 0.001). Among all the components of metabolic syndrome, only high triglyceride levels (>150mg/dL) at the baseline were significantly associated with both the development and regression of NAFLD in nonobese subjects (ORs, 1.54 (1.10-2.14), and 0.60 (0.38-0.96), respectively) CONCLUSIONS: Body weight change and baseline triglyceride levels were strong indicators for the development and regression of NAFLD in a nonobese population This article is protected by copyright. All rights reserved.
    Liver international: official journal of the International Association for the Study of the Liver 01/2014; · 4.41 Impact Factor
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    ABSTRACT: Minimally invasive cardiac surgery (MICS) requires lung isolation. Lung isolation is usually achieved with double-lumen endotracheal tube (DLT). Patients with idiopathic thrombocytopenic purpura (ITP) have an increased risk of bleeding events. We suspected endobronchial hemorrhage after exchange of DLT during induction of anesthesia for replacement of mitral valve in a 62-year-old man with a known ITP. The MICS was stopped and bronchial artery embolization was performed in the angiographic room. In the present case, in order to reduce the risk of bronchial arterial injury in ITP patient we intubated with single lumen endotracheal tube. Lung isolation led to achievement of intermittent total lung deflation. Based on the results, we recommend a high-dose intravenous immunoglobulin therapy and platelet transfusion prior to cardiac surgery in patients with ITP to increase platelet count. Moreover, it is proposed that in order to clear the vision during the operation, ventilation can be held or made intermittent both prior to cardiopulmonary bypass or at its conclusion to permit exposure.
    Korean journal of anesthesiology 01/2014; 66(1):59-63.
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    ABSTRACT: Administration of cocaine increases locomotor activity by enhancing dopamine transmission. To explore the peripheral mechanisms underlying acupuncture treatment for drug addiction, we developed a novel mechanical acupuncture instrument (MAI) for objective mechanical stimulation. The aim of this study was to evaluate whether acupuncture inhibition of cocaine-induced locomotor activity is mediated through specific peripheral nerves, the afferents from superficial or deep tissues, or specific groups of nerve fibers. Mechanical stimulation of acupuncture point HT7 with MAI suppressed cocaine-induced locomotor activity in a stimulus time-dependent manner, which was blocked by severing the ulnar nerve or by local anesthesia. Suppression of cocaine-induced locomotor activity was elicited after HT7 stimulation at frequencies of either 50 (for Meissner corpuscles) or 200 (for Pacinian corpuscles) Hz and was not affected by block of C/Aδ-fibers in the ulnar nerve with resiniferatoxin, nor generated by direct stimulation of C/Aδ-fiber afferents with capsaicin. These findings suggest that HT7 inhibition of cocaine-induced locomotor activity is mediated by A-fiber activation of ulnar nerve that originates in superficial and deep tissue.
    PLoS ONE 11/2013; 8(11):e81018. · 3.53 Impact Factor
  • Plant Omics 10/2013; 6(3):224-230. · 0.78 Impact Factor
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    ABSTRACT: Objectives : Many studies have investigated the electric specificity of meridian and acupoint. However, the definition about the real substance of 'Ki(Qi)' that flows in the meridian has not been established yet. The authors hypothesized that the 'Ki(Qi)' may be the very 'bioelectricity' of western medicine, from two common features that they are not visible with naked eyes and that they function in the living body only. Methods : 20 healthy adults participated in this study. Heart rate was measured before and after exercise. Acupuncture was performed at PC6 immediately after exercise with counter balance in the first experiment. In the second experiment, acupuncture group was further divided to the three groups, i.e. glove acupuncture group, manual acupuncture group, and NaCl acupuncture group. In the glove group, acupuncturist put on the two folds of latex gloves to block bioelectric currents between the acupuncturist and subject. In the NaCl group, acupuncturist had his fingertips wet with NaCl solution. Results : Exercise increased Heart Rate and acupuncture at PC6 inhibited this increase. In the second experiment, the significant difference compared to the comtrol group was the most in NaCl acupuncture and the least in Glove acupuncture. However, there was no significant difference between three groups. Conclusions : The results of this study seem to be deficient as a conclusive evidence for the hypothesis that the 'Ki(Qi)' of Korean Medicine is the 'bioelectricity' of western medicine.
    Korean Journal of Acupuncture. 09/2013; 30(3).
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    ABSTRACT: We have previously demonstrated that saikosaponin A (SSA) attenuated morphine self-administration behavior. In the present study, we evaluated the effects of SSA on cocaine-maintained responding using self-administration procedure. Rats self-administered cocaine (0.25mg/kg per infusion) under a fixed ratio 1 schedule of reinforcement during daily 3-hr session. Once stable basal responses were obtained, rats were pretreated with each doses of SSA (1.0, 2.5, 5.0mg/kg) or its vehicle (5% Tween-80) by an intraperitoneal injection 30min before the start of self-administration testing. Additionally, different groups of rats received either the selective GABAB antagonist SCH 50911or the GABAA antagonist bicuculline before systemic administration of SSA at dose of 2.5mg/kg. Results showed that SSA significantly reduced cocaine self-administration without affecting food consumption. SSA inhibition of cocaine reinforced-responding was blocked by SCH 50911, but not bicuculline. Results suggest that SSA may attenuate cocaine-reinforced behavior through activation of GABAB receptors.
    Neuroscience Letters 09/2013; · 2.06 Impact Factor
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    ABSTRACT: This prospective, double-blind, placebo-controlled study was designed to determine the efficacy of nitrous oxide (N2O) in alleviating the pain that followed sequential injection of propofol and rocuronium. A total of 205 adult patients (age, 18-68 years) received one of the following combinations: NaCl and 100 % O2 (group C); 0.5 mg/kg lidocaine and 100 % O2 (group L); NaCl and a mixture of 67 % N2O/O2 (group N); or 0.5 mg/kg lidocaine and a mixture of 67 % N2O/O2 (group LN). Vein occlusion was released after 1 min, and 5 ml propofol was injected over 10 s. Pain was evaluated on a visually enlarged, laminated, numeric rating (0-10) scale. The remainder of the induction dose of propofol (with a 3-ml bolus of normal saline and 0.6 mg/kg rocuronium) was then injected. The response to the rocuronium injection was assessed with a four-point scale (0-3). The incidence and severity of pain from the propofol injection in groups L, N, and LN were significantly lower than those in group C (P < 0.001). Frequency and intensity of the withdrawal response were significantly less in groups N and LN than in groups C and L (no response, P < 0.001; severe response, P < 0.001). Pretreatment with inhaled N2O can reduce the pain associated with propofol and rocuronium injection. Moreover, N2O (with or without lidocaine) is more effective than lidocaine alone in reducing rocuronium-related withdrawal reactions associated with sequential injection of propofol and rocuronium.
    Journal of Anesthesia 08/2013; · 1.12 Impact Factor
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    ABSTRACT: The microstructure and thermal expansion behavior of a Ti–23Nb–2Zr–0.7Ta–1.2O alloy (Gum metal) were investigated. A systematic diffraction pattern analysis using transmission electron microscopy revealed that a {11¯0}〈110〉-type transverse lattice modulation is present in the Ti–23Nb–2Zr–0.7Ta–1.2O alloy. Martensite-like nanodomains corresponding to {11¯0}〈110〉-type lattice modulations were observed in dark-field micrographs. Six variants of lattice modulation were confirmed to be distributed equivalently in the β phase in the annealed condition. Cold rolling resulted in preferential growth of a nanodomain variant which is most suited to releasing the applied stress although the long-range martensitic transformation was prevented by the local stress of the domain structure caused by oxygen atoms. It is suggested that the very small thermal expansion coefficient in the as-rolled specimen is caused by the preferential growth of the nanodomain variant due to residual stress.
    Acta Materialia. 08/2013; 61(13):4874–4886.
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    ABSTRACT: The combined effects of work hardening and precipitation strengthening were employed to improve the cyclic stability of TiNiPdCu-based high-temperature shape memory alloys. Annealing after cold deformation resulted in the formation of nano-scale TiPdCu and Ti2Pd precipitates, stable at high temperatures in Ti50Ni25−xPd25Cux alloys. The nano-scale precipitates were also observed to retard recovery/recrystallization processes at higher temperatures. It was found that the combined effects of work hardening and precipitation strengthening remarkably enhanced the high-temperature stability of the Ti50Ni20Pd25Cu5 alloy and increased its maximum working temperature range while keeping the transformation temperatures and recovery strains at sufficiently high levels. Precipitation strengthening helped to greatly improve the high-temperature cyclic stability of the alloy. Creep tests at 673 K under 500 MPa confirmed that the better high-temperature cyclic stability of the precipitate-containing alloy was mainly due to its higher creep resistance.
    Acta Materialia 08/2013; 61(13):4797–4810. · 3.94 Impact Factor

Publication Stats

883 Citations
335.18 Total Impact Points

Institutions

  • 2012–2014
    • Daegu Haany University
      Daikyū, Daegu, South Korea
  • 2007–2014
    • Korea University
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2004–2014
    • University of Tsukuba
      Tsukuba, Ibaraki, Japan
  • 2013
    • Korea Institute of Toxicology
      Sŏul, Seoul, South Korea
  • 2008–2013
    • University of Texas Medical Branch at Galveston
      • Department of Neuroscience and Cell Biology
      Galveston, TX, United States
  • 2004–2012
    • Ajou University
      • Department of Pharmacology
      Seoul, Seoul, South Korea
  • 2011
    • Yonsei University
      • Department of Information and Industrial Engineering
      Sŏul, Seoul, South Korea
    • Daegu University
      • College of Oriental Medicine
      Taegu, Daegu, South Korea
  • 2010
    • Asan Medical Center
      • Children's Hospital
      Sŏul, Seoul, South Korea
  • 2006–2009
    • Yonsei University Hospital
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
    • Dong-A University
      Tsau-liang-hai, Busan, South Korea
  • 2000–2007
    • Korea Research Institute of Chemical Technology
      • Division of Advanced Material
      Daiden, Daejeon, South Korea
  • 2003
    • Korea Advanced Institute of Science and Technology
      • Department of Chemical and Biomolecular Engineering
      Seoul, Seoul, South Korea
  • 1998
    • Chungnam National University
      • Department of Food and Nutrition
      Daiden, Daejeon, South Korea