Young Ho Shin

Seoul National University, Sŏul, Seoul, South Korea

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Publications (15)26.48 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: We present a multi-proxy record (pollen, microscopic charcoal, magnetic susceptibility, carbon-isotopic composition, total organic carbon [TOC], carbon/nitrogen [C/N] ratios, and particle size) of the late Holocene environmental change and human activities from Bongpo marsh on the east coast of Korea. Mutual interaction between the environment and humans during the late Holocene has not been properly investigated in Korea due to the lack of undisturbed samples with high sedimentation rates. In this study, the history of human responses to late Holocene environmental changes is clearly reconstructed using a multi-proxy paleoenvironmental approach that has not previously been applied in Korea. The evidence from Bongpo marsh indicates that 1) Bongpo marsh began to develop ca. 650 BC as a coastal lagoon was rapidly filled with organic matter, 2) agricultural disturbance around the study site remained slight until ca. AD 600, 3) full-scale intensive agriculture prevailed and the area of deforestation increased between ca. AD 600 and ca. AD 1870, and 4) the land use changed from lowland rice agriculture to upland cultivation when agricultural productivity declined after AD 1870, probably due to severe deforestation and the consequent heavy influx of clastic sediment on rice fields, as described in various historical documents.
    Quaternary Research 09/2012; 78(2):209–216. · 2.20 Impact Factor
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    ABSTRACT: We evaluated the clinical and radiologic results of impacted femoral neck fractures treated with multiple pinning and determined the influence of the progression of impaction at the fracture site on clinical outcome. There were 34 patients with a mean age of 65.5 years. The mean follow-up period was 3.4 years. Progression of fracture site impaction was measured using an articulo-trochanteric distance index and the percentage decrease in the articulo-trochanteric distance index between follow-up intervals. The failure of treatment was clarified as non-union and avascular necrosis. Other characteristics of the patients, including mean waiting time for surgery, preoperative Singh index score, and body mass index, were also measured to evaluate the influence on the clinical outcome of surgery. There were 6 fractures which were not treated successfully (3 non-union, 8.8% and 3 avascular necrosis, 8.8%). The mean percentage decrease of the articulo-trochanteric distance index within the first 6 weeks after surgery was 4.5% in the successful group and 25.1% in the failure group (p < 0.001). There was also a significant mean percentage decrease in the articulo-trochanteric distance index between 6 weeks and 3 months (p < 0.001). Primary stabilization with Knowles pins for impacted femoral neck fractures had a reasonable clinical outcome with low morbidity. Despite a significant difference of a mean percentage decrease in the articulo-trochanteric distance index between the successful group and the failure group, we could not verify it as a risk factor for failure of treatment because the odds ratio was not statistically significant.
    Clinics in orthopedic surgery 03/2012; 4(1):66-71.
  • Chris Hyunchul Jo, Young Ho Shin, Ji Sun Shin
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    ABSTRACT: This study examined the accuracy of our modified anterior approach to the glenohumeral joint using arthrography. Two hundred fifty-six consecutive patients with adhesive capsulitis received the glenohumeral joint injection: a mixture of 1 mL of 40 mg of triamcinolone hexacetonide, 2 mL of 2% lidocaine, 3 mL of contrast medium (Ioxitalamate), and 4 mL of normal saline solution, for a total of 10 mL, through a modified anterior approach. Anteroposterior, lateral, and axial arthrography after each injection was performed to determine the accuracy and patterns of the injection. The injection was judged to be successful if some of the contrast medium was placed within the joint. There were 78 male and 178 female patients, and the mean age was 54 years (range, 28 to 87 years). In 232 of the 256 patients (90.6%), the injection was deemed to have reached the glenohumeral joint, and these cases were considered successful. Among these patients, the contrast medium was shown only in the joint in 189 (73.8%), whereas in 43 (16.8%) it was shown both in and out of the joint. Of the 24 misguided injections, 15 (5.9%) had anterior placement, 6 (2.3%) had posterior placement, and 2 (0.8%) had superior placement, whereas the material was located in all portions outside the joint in 1 (0.4%). This study showed that our modified anterior approach had an accuracy greater than 90% for the intra-articular injection of the glenohumeral joint without radiographic guidance.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 08/2011; 27(10):1329-34. · 3.10 Impact Factor
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    ABSTRACT: It is not easy to apply tissue microarray (TMA) to atherectomized tissues from peripheral arterial disease because of their physical properties. We introduce a new TMA application technique for atherectomized tissues. Using a pre-made plastic TMA cassette and TMA punch device, we successfully made the TMA block containing 40 vertically oriented atherectomized tissue samples from 10 patients. The histogram of surface areas of tissue cores in the TMA showed a bell-shaped distribution, whereas that of conventionally embedded tissues showed wide distribution. This finding suggests that the TMA method might be a better way of vertical embedding than the conventional method. A TMA block prepared by our method enabled a simultaneous evaluation of the histopathology of vertically oriented atherectomized tissues and the correlation between them with intravascular ultrasound image. In addition, this new method might be applied to various tissues in different ways.
    Pathology - Research and Practice 07/2011; 207(9):568-72. · 1.21 Impact Factor
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    ABSTRACT: Cobalt nanoparticles with a face-centered cubic (fcc) structure were synthesized by the reduction of Co(NO3)2 in supercritical methanol. The reduction of Co(NO3)2 to fcc Co was completed within 15 min at 400 °C and 300 bar. The reduction mechanism was investigated by varying the reaction temperature (200–400 °C) and the reaction time (0.5–15 min). The results suggested that cobalt methoxynitrate formed at an initial stage was converted to CoO, and then reduced to Co. In addition, an introduction of oleic acid as a stabilizer achieved the formation of Co nanoparticles (∼10 nm).
    Materials Chemistry and Physics. 11/2010; 124(1):140–144.
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    ABSTRACT: Continuous synthesis of surface-modified zinc oxide (ZnO) nanoparticles was examined using surface modifiers (oleic acid and decanoic acid) in supercritical methanol at 400°C, 30MPa and a residence time of ∼40s. Wide angle X-ray diffraction (WAXD) analysis revealed that the surface-modified nanoparticles retained ZnO crystalline structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the surface modifiers changed drastically the size and morphology of the ZnO nanoparticles. When the molar ratio of oleic acid to Zn precursor ratio was 30, 10nm size particles with low degree of aggregation were produced. The surface-modified ZnO nanoparticles had higher BET surface areas (29–36m2/g) compared to unmodified ZnO particles synthesized in supercritical water (0.7m2/g). Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) indicated that aliphatic, carboxylate and hydroxyl groups were chemically attached on the surface of ZnO nanoparticles. Long-term (80 days) dispersion test using ultraviolet transmittance showed that the surface-modified ZnO particles had enhanced dispersion stability in ethylene glycol.
    Journal of Supercritical Fluids - J SUPERCRIT FLUID. 01/2010; 52(1):76-83.
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    ABSTRACT: The episodic nature of coastal dune development has been widely identified in many dune areas over the world. What causes such episodicity is still hotly debated. Sea-level change, climatic change and human impact have widely been reported as the main forcings, though there is no agreement yet upon which factors are critical. This research provides some evidence that sea-level fluctuation and climatic factors controlled the episodic dune building together, based upon optically stimulated luminescence (OSL) dune ages on the west coast of Korea. The newly obtained and published OSL dune ages on the west coast of the Taean Peninsula and Anmyeon Island, Korea, indicate the six main periods of dune building: 5.5, 4.3, 1.5, 1.3, 1.1 and 0.7 ka. They correlate with evidence of colder climate in East Asia that imply stronger dune-forming winds during the winter under the influence of a more intense Siberian High. They also correlate with periods of higher sea level over the present one with fluctuations. Thus, episodic dune activity along the west coast of the Korean Peninsula during the mid to late Holocene appears to be linked to stronger winter winds capable of moving sand from the beach to the foredune ridges with short-term fluctuations during the high stands. Copyright © 2009 John Wiley & Sons, Ltd.
    Journal of Quaternary Science 04/2009; 24(8):982 - 990. · 2.94 Impact Factor
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    ABSTRACT: A new supercritical water oxidation process for the simultaneous treatment of mixed wastewater containing wastewater from acrylonitrile manufacturing processes and copper-plating processes was investigated using a continuous tubular reactor system. Experiments were carried out at temperatures ranging from 400 to 600 degrees C and a pressure of 25 MPa. The residence time was fixed at 2s by changing the flow rates of feeds, depending on reaction temperature. The initial total organic carbon (TOC) concentration of the wastewaters and the O(2) concentration at the reactor inlet were kept constant at 0.49 and 0.74 mol/L. It was confirmed that the copper-plating wastewater accelerated the TOC conversion of acrylonitrile wastewater from 17.6% to 67.3% at a temperature of 450 degrees C. Moreover, copper and copper oxide nanoparticles were generated in the process of supercritical water oxidation (SCWO) of mixed wastewater. 99.8% of copper in mixed wastewater was recovered as solid copper and copper oxides at a temperature of 600 degrees C, with their average sizes ranging from 150 to 160 nm. Our study showed that SCWO provides a synergetic effect for simultaneous treatment of acrylonitrile and copper-plating wastewater. During the reaction, the oxidation rate of acrylonitrile wastewater was enhanced due to the in situ formation of nano-catalysts of copper and/or copper oxides, while the exothermic decomposition of acrylonitrile wastewater supplied enough heat for the recovery of solid copper and copper oxides from copper-plating wastewater. The synergetic effect of wastewater treatment by the newly proposed SCWO process leads to full TOC conversion, color removal, detoxification, and odor elimination, as well as full recovery of copper.
    Journal of hazardous materials 02/2009; 167(1-3):824-9. · 4.14 Impact Factor
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    ABSTRACT: A detailed investigation was made into the production of high temperature lithium cobalt oxide (HT-LiCoO2) particles by continuous hydrothermal synthesis via the reaction of cobalt nitrate, lithium hydroxide, and hydrogen peroxide. The experiments were carried out in both subcritical and supercritical water, at temperatures ranging from 300 to 411°C, with residence times less than 1min in all instances. Although Co3O4 particles were synthesized in subcritical water at similar reaction conditions designed for comparison, well-ordered particles of HT-LiCoO2 were obtained in supercritical water. In supercritical conditions, the variations in temperature and residence time did not have significant impacts on the average particle size, particle size distribution, or morphology of obtained HT-LiCoO2. However, it was important to supply excessive lithium hydroxide and hydrogen peroxide in order to synthesize single-phased HT-LiCoO2 particles without undesired by-products. The hydrothermal synthetic route for LiCoO2, CoO, and Co3O4 in both subcritical and supercritical conditions was postulated.
    Journal of Supercritical Fluids - J SUPERCRIT FLUID. 01/2009; 50(3):250-256.
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    ABSTRACT: Surface-modified ceria oxide (CeO2) nanoparticles were synthesized continuously in supercritical methanol at 400°C, 30MPa and a residence time of ∼40s using a flow type reactor system. Oleic acid and decanoic acid were used as the surface modifiers. Transmission electron microscopy (TEM) showed that the surface modifiers changed drastically the shape and size of the nanoparticles. When 0.3M of the surface modifiers were used, primary particles with diameter of 2–3nm loosely aggregated and formed secondary particles with size of 30–50nm. Wide angle X-ray diffraction (WAXD) analysis revealed that the surface-modified nanoparticles retained CeO2 crystalline structure. The surface-modified CeO2 nanoparticles had a very high surface area (140–193m2/g) compared to the unmodified CeO2 particles synthesized in supercritical water (8.5m2/g). Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) indicated that aliphatic, carboxylate and hydroxyl groups were chemically bounded on the surface of CeO2 nanoparticles. Dispersability test using ultraviolet transmittance showed that most of the surface-modified CeO2 nanoparticles were dispersed in ethylene glycol for 30 days while the unmodified CeO2 particles synthesized in supercritical water or in supercritical methanol were precipitated after 7–15 days.
    Journal of Supercritical Fluids The 01/2009; 50(3):283-291. · 2.73 Impact Factor
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    ABSTRACT: The wastewater from an acrylonitrile manufacturing plant, which is difficult to biodegrade, was decomposed in subcritical and supercritical water. Experiments were carried out at temperature ranging from 299 to 552 degrees C and a pressure of 25 MPa. The initial total organic carbon (TOC) of acrylonitrile wastewater was set from 0.27 to 2.10 mol L(-1) with residence times ranging from 3 to 30s. 30 wt.% H(2)O(2) solution was used as an oxidant with the stoichiometric ratios of O(2) based on the initial TOC concentration ranging from 0.5 to 2.5. TOC conversion increased with increasing reaction temperature and residence time, however, beyond the stoichiometric oxygen-TOC ratio of 1:1, TOC conversion was barely affected by excess oxygen. The initial TOC concentration of acrylonitrile wastewater also had a negligible effect on TOC conversion. An assumed pseudo-first-order global rate expression was determined with an activation energy of 53.48(+/-33.57)kJ mol(-1) and a pre-exponential factor of 5.22(+/-1.74)x10(2)s(-1). By considering the dependence of the reaction rate on TOC and O(2) concentration, a global rate expression was regressed from the complete set of 64 data points. The resulting activation energy was 66.33(+/-5.87)kJ mol(-1); the pre-exponential factor was 6.07(+/-6.89)x10(3)mol(-0.26)s(-1); and the reaction orders for initial TOC and O(2) concentration were 1.26(+/-0.15) and 0.00(+/-0.15), respectively.
    Journal of hazardous materials 08/2008; 163(2-3):1142-7. · 4.14 Impact Factor
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    ABSTRACT: Carbon dioxide emission and nitrogen pollution caused by nitrogen-containing wastes have become global environmental issues in recent years. To simultaneously reduce the discharge of carbon dioxide and reactive nitrogen during the conventional supercritical water oxidation (SCWO), we have developed an advanced SCWO process involving the treatment of nitrogen-containing wastewater. By introducing Ca(NO3)2 to the reactor inlet and Ca(OH)2 to the reactor outlet, 94% of the carbon and 95% of the reactive nitrogen in acrylonitrile (C3H3N) were simultaneously converted to solid CaCO3 and innocuous nitrogen gas at 250 bar and 420 °C. In situ formed CaCO3 in the reactor acted as a catalyst for the decomposition of acrylonitrile. Furthermore, CaCO3 with average particle size of 1.72 μm can either be used for industrial applications or reconverted to Ca(NO3)2, which can be recycled to the reactor, and carbon dioxide, which can be injected into deep geological formations. This novel method provides inherently cleaner SCWO process which offers an attractive solution for the capture of carbon dioxide and reduction of total nitrogen (TN) from nitrogen-containing wastewater, as well as the removal of total organic carbon (TOC).
    Journal of Supercritical Fluids The 72:120–124. · 2.73 Impact Factor
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    ABSTRACT: Biodiesel and zinc oxide nanoparticles were synthesized simultaneously using supercritical methanol. Zinc nitrate was used as the source of zinc for the formation of the zinc oxide nanoparticles, which acted as a catalyst during the transesterification of rapeseed oil. In addition, the in situ formed zinc oxide nanoparticles led to a reduction in the reaction temperature and time. The fatty acid methyl ester (FAME) yields in the various biodiesels synthesized were determined using gas chromatography (GC). The zinc oxide nanoparticles formed were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. The results of these analyses confirmed the formation of surface-modified zinc oxide nanoparticles of sizes smaller than those obtained using conventional techniques. This newly developed method provides an economical advantage since it results in the lowering of the operational temperature and the production of zinc oxide as an additional byproduct.
    Fuel. 109:279–284.
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    ABSTRACT: Hydrothermal synthesis of cerium oxide nanocrystals was performed with in-situ surface modification using soybean oil and palm oil as capping agents. The synthesized nanocrystals were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). TEM results showed single crystalline nature with stable dispersion. FT-IR spectra and TGA plots further confirmed the adsorption of fatty acid molecules onto cerium oxide surface. Our findings have the advantages of reduced materials costs compared to using single component surfactants and the production of valuable by-product glycerol.
    Korean Journal of Chemical Engineering 29(10). · 1.06 Impact Factor
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    ABSTRACT: We present a record of Holocene environmental change on the east coast of Korea, inferred using pollen, carbon-isotopic composition (δ13C), total organic carbon, total sulfur, carbon/nitrogen ratios, particle size analysis and major element geochemistry in a sediment core from Soonpogae Lagoon. A multi-proxy paleoenvironmental approach had not previously been applied in Korea and allowed us to reconstruct climate and vegetation change, sea-level rise, lagoon development, and human impact on the east coast of Korea over the last 8,000 years. Evidence from Soonpogae Lagoon supports the following three conclusions: (1) As a drying trend prevailed on the east coast of Korea after ~5,900 cal yr BP, chemical weathering weakened and herbaceous plants became more important than during the previous humid phase (Holocene Climate Optimum), (2) Sea-level rise on the east coast slowed dramatically about 6,800 cal yr BP, resulting in low rates of sedimentation in Soonpogae Lagoon, and (3) Soonpogae Lagoon was almost completely isolated from the sea by sand barriers when human impact intensified ~2,100 BP.
    Journal of Paleolimnology 48(3). · 2.21 Impact Factor