Hyun-Moo Cho

Comparison of four hematology analyzers, CELL‐DYN Sapphire, ADVIA 120, Coulter LH 750, and Sysmex XE‐2100, in terms of clinical usefulness

We evaluated the clinical usefulness (leukocyte distribution classification, morphologic classification, and morphologic flags) of the following four hematology analyzers: CELL‐DYN Sapphire (CD‐Sapphire) (Abbott Diagnostics, Santa Clara, CA, USA), ADVIA 120 (Bayer Diagnostics, Tarrytown, NY, USA), Beckman Coulter LH 750 (Beckman Coulter, Miami, FL, USA), and Sysmex XE‐2100 (TOA Medical Electronics Co., Kobe, Japan). Four hundred thirty samples from patients and 100 samples from healthy individuals were analyzed. For distributional classification, the sensitivity rates of CD‐Sapphire, ADVIA 120, LH 750, and XE‐2100 were 93.1, 95.9, 94.9, and 94.9%, respectively, and the efficiency rates were 80.7, 81.6, 84.1, and 84.2%, respectively. For morphologic classification, the sensitivity rates of CD‐Sapphire, ADVIA 120, LH 750, and XE‐2100 were 88.6, 93.2, 77.3, and 94.3%, respectively, and the efficiency rates were 80.9, 73.0, 79.5, and 74.2%, respectively. Comparing the findings in different morphologic flags, XE‐2100 showed the highest sensitivity for Blasts flag (90.9%); CD‐Sapphire showed the highest sensitivity for Immature granulocytes and/or Left‐shift flag (85.5%); ADVIA 120 showed the highest sensitivity for Atypical lymphocytes flag (60.0%); and LH 750 showed the highest sensitivity for Nucleated RBC flag (75.0%). Our results demonstrate that the four analyzers are comparable in overall performance.

Crustal structure of the continental margin of Korea in the East Sea (Japan Sea) from deep seismic sounding data : evidence for rifting affected by the hotter than normal mantle

Abstract Despite the various opening models of the southwestern part of the East Sea (Japan Sea) between the Korean Peninsula and the Japan Arc, the continental margin of the Korean Peninsula remains unknown in crustal structure. As a result, continental rifting and subsequent seafloor spreading processes to explain the opening of the East Sea have not been adequately addressed. We investigated crustal and sedimentary velocity structures across the Korean margin into the adjacent Ulleung Basin from multichannel seismic (MCS) reflection and ocean bottom seismometer (OBS) data. The Ulleung Basin shows crustal velocity structure typical of oceanic although its crustal thickness of about 10 km is greater than normal. The continental margin documents rapid transition from continental to oceanic crust, exhibiting a remarkable decrease in crustal thickness accompanied by shallowing of Moho over a distance of about 50 km. The crustal model of the margin is characterized by a high-velocity (up to 7.4 km/s) lower crustal (HVLC) layer that is thicker than 10 km under the slope base and pinches out seawards. The HVLC layer is interpreted as magmatic underplating emplaced during continental rifting in response to high upper mantle temperature. The acoustic basement of the slope base shows an igneous stratigraphy developed by massive volcanic eruption. These features suggest that the evolution of the Korean margin can be explained by the processes occurring at volcanic rifted margins. Global earthquake tomography supports our interpretation by defining the abnormally hot upper mantle across the Korean margin and in the Ulleung Basin.

Prognostic value of platelet indices as determined by ADVIA 120 in patients suspected of having disseminated intravascular coagulation

Recent technological advances have made it possible to record a variety of platelet indices using automated hematology analyzers. Disseminated intravascular coagulation (DIC) is associated with the dramatic hemostasis activation, with evidence of fibrin formation and platelet consumption. We investigated the prognostic significance of platelet indices as measured by ADVIA in 222 patients suspected of having DIC. The presence of overt DIC was defined using the scoring system of the International Society of Thrombosis and Haemostasis Subcommittee. Twenty‐eight day hospital mortality was used as a clinical prognosis parameter. Median platelet count and platelet‐crit (PCT) levels markedly decreased in nonsurvivors, whereas mean platelet volume (MPV), platelet component distribution width (PCDW) and platelet dry mass distribution width (PMDW) were significantly increased in nonsurvivors. In terms of ROC analysis, which was conducted to predict 28‐day mortality, areas under the receiver operating characteristic curve (AUC) were; 0.73 platelet count, 0.72 for PCT, 0.69 for PCDW, 0.65 for PMDW and 0.61 for MPV. The odds ratio of a reduced platelet count for the relative risk of 28‐day mortality was 5.249 (95% CI: 2.399–11.486), and the odds ratio for PCDW was 3.240 and for PMDW 3.262. Among these indices, platelet count, PCDW and PMDW were found to be more predictive of 28‐day hospital mortality. Our results suggest that these indices may provide prognostic information on hospital mortality in the patients suspected of having DIC.

Numerical experiments on three dimensional seismic tomography using graph theoretical ray tracing

Numerical experiments on 3-D seismic tomography implemented by graph theoretical ray tracing and conjugate gradient (CG) inversion method for the laterally inhomogeneous media is presented with emphasis on the technique of improving the resolution of the reconstructed image. Graph theoretical ray tracing is efficient and useful for calculating the traveltime of the first arrival seismic signal and the corresponding ray path. It can trace accurate and stable ray path and produce corresponding traveltime even in the complicated 3-D medium in which traditional ray tracing methods fails. In this study, two kinds of forward-star set, the spherical and the cubic, for the graph theoretical ray tracing were designed. The features of each forward-star set were examined. In the spherical forward-star, the angle between two adjacent forward-star nodes is constant as is in the cubic forward-star but the number of forward-star node is about two third of that of the cubic when the same forward-star level is selected. Thus the computation time of ray tracing is reduced using the spherical forward-star set. We employ the CG method for inversion, because it is fast and has a good convergence rate compared with other inversion schemes. In the tomographic process with some source-receiver configurations, the reconstructed images are distorted and elongated when only one direction of source-receiver configuration is used. However, more accurate image was obtained with two directions of source-receiver configuration, especially in orthogonal direction. The numerical simulations with iterative operations of ray tracing and CG inversion for structured models of an spheroidal body and an elongated sedimentary basin show that the technique presented in this paper is useful to reconstruct subsurface image of 3-D inhomogeneous media with small number of iteration.