Tae Hoon Lee

Chonnam National University, Gwangju, Gwangju, South Korea

Are you Tae Hoon Lee?

Claim your profile

Publications (110)323.87 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The presence of microcalcification on mammography is one of the earliest signs in breast cancer detection. However, it is difficult to distinguish malignant calcifications from benign calcifications. The aim of this study is to evaluate correlation between changing patterns of microcalcification on screening mammography and malignant breast lesions. Medical records and diagnostic images of 67 women who had previously undergone at least two digital mammograms at least 6 months apart and underwent mammography-guided needle localization and surgical excision between 2011 and 2013 were retrospectively reviewed and analyzed. Breast cancer was detected in the surgical specimens of 20 patients (29.9 %). Annual change of extent of microcalcification on mammography showed statistically significant correlation with pathologic outcome (P = 0.023). The changing pattern of new appearance or increased extent of microcalcification on mammography had positive predictive value of 54.8 % for breast cancer, and it was a statistically significant predictor for breast cancer (P = 0.012). Shape or number change of microcalcification without increased extent had less accurate predictive value for breast cancer, particularly in women younger than 50 years (P < 0.001). This study showed that the pattern of increased extent of microcalcification on screening mammography was a significant predictor for breast cancer. We suggest that mammography-guided needle localization and surgical excision should be considered when increased extent of microcalcification is observed on screening mammography and closed follow-up without pathologic confirmation can be permitted if absence of extension of microcalcification was confirmed in women younger than 50 years.
    Breast Cancer 02/2015; · 1.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The main obstacles to achieving high electrochemical energy density while retaining high power density are the trade-offs of energy versus power and gravimetric versus volumetric density. Optimizing structural parameters is the key to circumvent these trade-offs. We report here the synthesis of carbon nanotube (CNT)-bridged graphene 3D building blocks via the Coulombic interaction between positively charged CNTs grafted by cationic surfactants, and negatively charged graphene oxide sheets, followed by KOH activation. The CNTs were intercalated into the nanoporous graphene layers to build pillared 3D structures which enhance accessible surface area and allow fast ion diffusion. The resulting graphene/CNT films are free-standing and flexible with a high electrical conductivity of 39,400 S m(-1) and a reasonable mass density of 1.06 g cm(-3). The supercapacitors fabricated using these films exhibit the outstanding electrochemical performance in an ionic liquid electrolyte with a maximum energy density of 117.2 Wh L(-1) or 110.6 Wh kg(-1) at a maximum power density of 424 kW L(-1) or 400 kW kg(-1), which is based on thickness or mass of total active material.
    ACS Nano 02/2015; · 12.03 Impact Factor
  • Advanced Energy Materials 02/2015; · 14.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A bi-layered hydrogel strip was developed to generate a spirally coiled shape by swell-induced deformation. The coil diameters were adjusted by controlling the swelling and elastic properties of the hydrogels in each layer, which were tuned by the concentration of a crosslinker. The volume swelling ratio decreased as the crosslinker concentration increased. To simulate spirally coiled deformation of a bi-layered hydrogel strip, a novel structural analysis approach based on the finite element method was proposed. Instead of solving multiple sets of complex equations for solvent transport and stress development, the volume swelling coefficients of saturated hydrogels with various crosslinker concentrations were measured and used in computational deformation analysis. A thermal analogy was implemented to resolve the swell-induced deformation. Deformation of a thin straight strip into a spiral coil shape due to swelling was successfully simulated, and the computed coil diameters showed good agreement with the experimental results.
    International Journal of Precision Engineering and Manufacturing 02/2015; 16(2). · 1.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Inpatient status can cause inadequate bowel preparation. The majority of previous studies regarding bowel preparation have focused on comparing the effects of different purgative regimens in outpatients. However, data on bowel preparation for inpatients are lacking. The aim of this study was to investigate whether bisacodyl plus polyethylene glycol (PEG) can improve bowel preparation in hospitalized patients. A prospective, randomized and observer-blind study was performed. A total of 196 hospitalized patients undergoing colonoscopy were randomized to receive 4 L PEG (PEG only group) or 4 L PEG+bisacodyl 10 mg (bisacodyl added group). The adequacy of bowel preparation was scored using the Ottawa bowel preparation scale. One hundred and eighty-three subjects completed the study; 96 in the bisacodyl added group and 87 in the PEG only group. There were no significant differences between the bisacodyl added group and the PEG only group with respect to the score of bowel cleansing (3.59±B1;2.81 vs. 3.82±B1;3.03, p=0.607), quality of bowel cleansing (adequate preparation 89.6% vs. 85.1%, p=0.380), and overall adverse events (66.7% vs. 52.9%, p=0.057). However, a larger proportion of patients in the PEG only group were able to ingest the entire solution as prescribed than in the bisacodyl added group (98.9% vs. 75.0%, p<0.001). In hospitalized patients, the quality of bowel preparation did not differ depending on whether bisacodyl is added or not. In addition, patient compliance based on consumption of cleansing agent was better in the PEG only group. (Korean J Gastroenterol 2014;64:268-277).
    The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 11/2014; 64(5):268-77.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the feasibility of polyvinyl alcohol (PVA) polymer coil as a new endovascular embolic agent and to gauge the related histologic response in a canine vascular model.Materials and MethodsPVA polymer coil was fabricated by cross-linking PVA and tantalum particles. Basic properties were then studied in vitro via swelling ratio and bending diameter. Normal renal segmental arteries and wide-necked aneurysms of carotid sidewalls served as canine vascular models. Endovascular PVA coil embolization of normal renal segmental arteries (N = 20) and carotid aneurysms (N = 8) was performed under fluoroscopic guidance in 10 dogs. Degree of occlusion was assessed immediately and at 4 weeks after embolization by conventional and computed tomographic angiography. Histologic features were also graded at acute (day 1, six segmental arteries and four aneurysms) and chronic phases (week 4, 14 segmental arteries and four aneurysms) after embolization to assess inflammation, organization of thrombus, and neointimal proliferation.ResultsSwelling ratio declined as concentrations of cross-linking agent increased. Mean bending diameters were 2.05 mm (range, 0.86–6.25 mm) in water at 37°C and 2.29 mm (range, 0.94–6.38 mm) in canine blood samples at 37°C. Occlusion of normal renal segmental arteries was sustained (complete occlusion at day 1, n = 20; at week 4, n = 14), whereas immediate outcomes in carotid aneurysms (day 1, complete occlusion, n = 5; residual neck only, n = 3) were not sustained (week 4, complete occlusion, n = 1; minor recanalization, n = 1; major recanalization, n = 2). At week 4, chronic inflammatory cells predominated, with progressive organization of thrombus and fibrocellular ingrowth. All aneurysms bore full neointimal linings on the coil mass in the chronic phase.Conclusions Vascular occlusion by PVA polymer coil proved superior in normal renal segmental arteries and feasible in surgically constructed carotid aneurysms (with packing densities ≥ 30%), constituting acceptable radiologic feasibility and histologic response.
    Journal of Vascular and Interventional Radiology 11/2014; · 2.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: New or missed gastric cancer rates after negative endoscopy are high. However, the clinicopathologic characteristics of missed or interval early gastric cancer (EGC) are not well known. The aim of this study was to evaluate clinicopathologic and endoscopic characteristics of missed or interval EGC after negative endoscopy.
    Digestive Diseases and Sciences 10/2014; · 2.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Metabolic health is an emerging concept that is highly correlated with various metabolic complications, and adipocytokines have been causally linked to a wide range of metabolic diseases. Thus, this study compared serum adipocytokine levels according to metabolic health and obesity status.
    Endocrinology and metabolism (Seoul, Korea). 09/2014;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Chronic kidney disease (CKD) is considered one of the most common risk factors for cardiovascular disease. Coronary artery calcification (CAC) is a potential mechanism that explains the association between renal function and cardiovascular mortality. We aimed to evaluate the association between renal function and CAC in apparently healthy Korean subjects.
    Endocrinology and metabolism (Seoul, Korea). 09/2014; 29(3):312-9.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Adenoma detection rate (ADR) is widely used as an index of colonoscopy quality management. Although advanced adenomas can be found less frequently than non-advanced adenomas, advanced adenomas have a higher clinical significance during screening for colorectal cancer. The aim of this study was to investigate the correlation between advanced and non-advanced ADR among colonoscopists.
    The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 07/2014; 64(1):18-23.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The hypertriglyceridemic waist (HTGW) phenotype is a simple and inexpensive screening parameter to identify people at increased risk of cardiovascular disease. We evaluated whether the HTGW phenotype predicts diabetes in urban Korean adults.
    Endocrinology and metabolism (Seoul, Korea). 07/2014; 29(4).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate distinct entanglement of single-walled carbon nanotube (SWCNT) and multiwalled carbon nanotube (MWCNT) clusters in nematic liquid crystal medium using scanning electron microscopy technique and the entanglement influence on electric field-induced stretching phenomena of the said clusters in the same medium under optical microscopy investigation. The observed stretching threshold field for MWCNT clusters is found to be higher than the SWCNT counterpart caused by the interplay between attractive field-induced dipolar interaction of intercarbon nanotube (CNT) bundles and the distinct degree of entanglement of neighboring CNT bundles. Subsequently observed different tensile elasticity modulus results for different CNT kinds also confirm different CNT bundle entanglement and attractive dipolar interaction between adjacent CNT bundles in CNT clusters are responsible for distinct stretching threshold field behavior.
    Physical Review E 07/2014; 90(1-1):012508. · 2.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BackgroundThe risk of various complications after Achilles tendon lengthening is mainly related to the length of surgical exposure and the lengthening method. A comprehensive technique to minimize the complications is required.MethodsThe treatment of Achilles tendon tightness in 57 patients (95 ankles) were performed by using a short transverse incision on a skin crease of the heel and by Z-lengthening of the tendon. In the severe cases, two or three transverse incisions were required for greater lengthening of the tendon, and a serial cast or Ilizarov apparatus was applied for the gradual correction. The results of these 95 ankles were compared to those of 18 ankles, which underwent percutaneous sliding lengthening, and to the 19 ankles, which received Z-lengthening with a medial longitudinal incision.ResultsThe functional and cosmetic satisfaction was achieved among those who underwent the tendon lengthening with the new technique. The mean American Orthopaedic Foot & Ankle Society (AOFAS) score improved from 56.1 to 81.8. The second operations to correct recurrence were performed in the two cerebral palsy patients.ConclusionsThe new technique has a low rate of complications such as scarring, adhesion, total transection, excessive lengthening, and recurrence of shortening. The excellent cosmesis and the short operation time are the additional advantages.
    Clinics in orthopedic surgery 06/2014; 6(2):208-215.
    This article is viewable in ResearchGate's enriched format
  • [Show abstract] [Hide abstract]
    ABSTRACT: Redox balance has been suggested as an important determinant of “stemness” in embryonic stem cells (ESCs). In this study, we demonstrate that peroxiredoxin (Prx) plays a pivotal role in maintenance of ESC stemness during neurogenesis through suppression of reactive oxygen species (ROS)-sensitive signaling. During neurogenesis, Prx I and Oct4 are expressed in a mutually dependent manner and their expression is abruptly downregulated by an excess of ROS. Thus, in Prx I−/− or Prx II−/− ESCs, rapid loss of stemness can occur due to spontaneous ROS overload, leading to their active commitment into neurons; however, stemness is restored by the addition of an antioxidant or an inhibitor of c-Jun N-terminal kinase (JNK). In addition, Prx I and Prx II appear to have a tight association with the mechanism underlying the protection of ESC stemness in developing teratomas. These results suggest that Prx functions as a protector of ESC stemness by opposing ROS/JNK cascades during neurogenesis. Therefore, our findings have important implications for understanding of maintenance of ESC stemness through involvement of antioxidant enzymes and may lead to development of an alternative stem cell-based therapeutic strategy for production of high-quality neurons in large quantity. Stem Cells 2014;32:998–1011
    Stem Cells 04/2014; 32(4). · 7.70 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The objectives of this study were to assess the potential value of Ki-67 in predicting response to neoadjuvant chemotherapy in breast cancer patients and to suggest a reasonable cutoff value for classifying Ki-67 expression. This study included 74 breast cancer patients who underwent surgery after anthracycline-based neoadjuvant chemotherapy between 2007 and 2012. We analyzed the clinical and immunohistochemical characteristics using core biopsy specimens obtained before neoadjuvant chemotherapy to determine their correlations with the response to chemotherapy. A clinical complete response was observed in 6 patients (8.1%); a clinical partial response, in 44 patients (59.5%); and clinical stable disease, in 24 patients (32.4%). A pathologic complete response (pCR) was observed in 10 patients (13.5%). In univariate analysis, estrogen receptor (ER) negativity (p=0.031), human epidermal growth factor receptor 2 (HER2) positivity (p=0.040), and high Ki-67 expression (p=0.036) were predictive factors for a pCR. In multivariate analysis, Ki-67 was the only independent predictor of a pCR (p=0.049). The analysis of Ki-67 values revealed that 25% was a reasonable cutoff value for predicting the response to chemotherapy. In subgroup analysis, a higher Ki-67 value (≥25%) was a significant predictive factor for the response to neoadjuvant chemotherapy, especially in ER-negative and HER2-positive breast cancer patients. Ki-67 expression in breast cancer tissue may be an effective factor for predicting the response to neoadjuvant chemotherapy. We suggest that a 25% level of Ki-67 expression is a reasonable cutoff value for predicting a response to chemotherapy. Moreover, Ki-67 is a useful predictive factor for pCR, especially in patients with ER-negative and HER2-positive breast cancer.
    Journal of Breast Cancer 03/2014; 17(1):40-6. · 1.32 Impact Factor
    This article is viewable in ResearchGate's enriched format
  • Sunnyeo Lee, Jonghyun Sim, Tae Hoon Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider a Higgs boson field coupled to Brans-Dicke gravity and calculate its contributions to the energy density and pressure in the Friedmann-Robertson-Walker spacetime. We seek de Sitter solutions for the cosmic scale factor with well-incorporated Higgs and Brans-Dicke fields and investigate the stability properties of the solutions by using a linear approximation. We discuss the possibility that the late-time acceleration and the inflationary era of our universe can be described by means of scalar fields with self-interactions and a Yukawa potential.
    Journal- Korean Physical Society 01/2014; 64(4). · 0.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report vertically aligned ZnO nanowire arrays (ZnO NWAs) were fabricated on 3D graphene foam (GF) and used to selectively detect uric acid (UA), dopamine (DA), and ascorbic acid (AA) by a differential pulse voltammetry method. The optimised ZnO NWA/GF electrode provided a high surface area and high selectivity with a detection limit of 1 nM for UA and DA. The high selectivity in the oxidation potential was explained by the gap difference between the lowest unoccupied and highest occupied molecular orbitals of a biomolecule for a set of given electrodes. This method was further used to detect UA levels in the serum of patients with Parkinson's disease (PD). The UA level was 25% lower in PD patients than in healthy individuals. This finding strongly implies that UA can be used as a biomarker for PD.
    ACS Nano 01/2014; · 12.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electric field induced dynamic reorientation phenomenon of graphene/graphitic flakes in homogeneously aligned nematic liquid crystal (NLC) medium has been demonstrated by optical microscopy. The flakes reorient from parallel to perpendicular configuration with respect to boundary plates of confining cells for an applied field strength of as low as tens of millivolt per micrometer. After field removal the reoriented flakes recover to their initial state with the help of relaxation of NLC. Considering flake reorientation phenomenon both in positive and negative dielectric anisotropy NLCs, the reorientation process depends on interfacial Maxwell-Wagner polarization and NLC director reorientation. We propose a phenomenological model based on electric field induced potential energy of graphitic flakes and coupling contribution of positive NLC to generate the rotational kinetic energy for flake reorientation. The model successfully explains the dependence of flake reorientation time over flake shape anisotropy, electric-field strength, and flake area. Using present operating scheme it is possible to generate dark field-off state and bright field-on state, having application potential for electro-optic light modulation devices.
    Optics Express 08/2013; 21(17):19867-19879. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: The mechanism of pancreatitis development following endoscopic papillary balloon dilation (EPBD) remains unknown. Antegrade dilation with percutaneous transhepatic papillary balloon dilation (PTPBD) allows the removal of bile duct stones or fragments during percutaneous choledochoscopic lithotomy, with less mechanical trauma to the papilla than with EPBD-mediated stone removal. METHODS: A total of 56 patients with bile duct stones underwent antegrade dilation with PTPBD from March 2006 to February 2011. A total of 208 patients with CBD stones underwent retrograde dilation with EPBD during the same period. The conditions of papillary balloon dilation were identical in both groups. The frequencies of pancreatitis and hyperamylasemia were compared in both groups. RESULTS: Pancreatitis occurred in 14 (6.7%) of 208 patients in the EPBD group (mild: nine, moderate: four, severe: one). There was no case of pancreatitis among 56 patients in the PTPBD group (P < 0.05). Hyperamylasemia developed in significantly more patients treated in the EPBD group (62, 29.8%) compared with the PTPBD group (4, 7.1%; P < 0.05). Complete bile duct clearance was achieved in 98.2% of PTPBD group and 97.1% of EPBD group. CONCLUSIONS: The rates of post-procedural pancreatitis and hyperamylasemia were significantly higher after retrograde dilation with EPBD than after antegrade dilation with PTPBD for the removal of bile duct stones. Although the mechanism of pancreatitis following papillary balloon dilation remains unclear, post-EPBD pancreatitis may be associated with procedures before and after balloon dilation similar to mechanical lithotripsy, rather than balloon dilation itself.
    Journal of Gastroenterology and Hepatology 05/2013; · 3.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The BARD score is a model to detect advanced liver fibrosis in nonalcoholic fatty liver disease (NAFLD) patients. The aims of this study were to identify additional factors and then to build an enhanced version of the BARD score. One hundred seven patients with biopsy-proven NAFLD were enrolled retrospectively. Logistic regressions were performed to identify independent risk factors for advanced liver fibrosis (stage 3 or 4). An enhanced model of the BARD score (BARDI score) was built and evaluated with a receiver operating characteristic (ROC) curve. In multivariate analysis, age (odds ratio [OR], 0.89; p=0.04), aspartate aminotransferase/alanine aminotransferase ratio (OR, 1.73; p<0.01), and international normalized ratio (INR) (OR, 8.85; p<0.01) were independently significant factors. The BARDI score was created by adding the INR to the BARD. The area under the ROC curve of the BARDI score was significantly larger than that of the BARD score (0.881 vs 0.808, p<0.01). A BARDI score of 3 or more showed a positive predictive value (PPV) of 51.0% and a negative predictive value (NPV) of 96.0%. The BARDI score had an improved PPV over the BARD score and maintained an excellent NPV. Further study is warranted for its external validation and comparison with other models.
    Gut and liver 05/2013; 7(3):323-328. · 1.49 Impact Factor
    This article is viewable in ResearchGate's enriched format

Publication Stats

575 Citations
323.87 Total Impact Points

Institutions

  • 2014
    • Chonnam National University
      • Department of Biochemistry
      Gwangju, Gwangju, South Korea
    • Pusan National University
      • Department of Orthopaedic Surgery
      Tsau-liang-hai, Busan, South Korea
    • Kangbuk Samsung Hospital
      Sŏul, Seoul, South Korea
    • Sungkyunkwan University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 2002–2014
    • Soongsil University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 2012–2013
    • Marshall University
      • Department of Internal Medicine
      Huntington, WV, United States
    • Harvard Medical School
      Boston, Massachusetts, United States
  • 2009–2013
    • Soon Chun Hyang University Hospital
      • Department of Gastroenterology
      Sŏul, Seoul, South Korea
  • 2008–2013
    • Soonchunhyang University
      • College of Medicine
      Onyang, South Chungcheong, South Korea
    • Mayo Foundation for Medical Education and Research
      • Division of Gastroenterology and Hepatology
      Scottsdale, AZ, United States
  • 2011
    • Kyung Hee University Medical Center
      Sŏul, Seoul, South Korea
    • Asan Medical Center
      • Department of Gastroenterology
      Seoul, Seoul, South Korea
  • 2002–2011
    • Yonsei University
      • Department of Electrical and Electronic Engineering
      Sŏul, Seoul, South Korea
  • 2009–2010
    • Yonsei University Hospital
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
  • 2005–2009
    • Ewha Womans University
      • • Department of Neurosurgery
      • • Department of Science Education
      Sŏul, Seoul, South Korea
  • 2007
    • Mayo Clinic - Rochester
      • Department of Gastroenterology and Hepatology
      Rochester, Minnesota, United States
  • 2003–2004
    • Korea Atomic Energy Research Institute (KAERI)
      Daiden, Daejeon, South Korea