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Search Results: 1 - 10 of 29226 matches for " Seung Mi Lee "
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Comparative Study of Various Preparation Methods of Colloidal Silica  [PDF]
Hyung Mi Lim, Jinho Lee, Jeong-Hwan Jeong, Seong-Geun Oh, Seung-Ho Lee
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.212126
Abstract: Colloidal silica can be prepared by various methods and starting materials including ion exchange of aqueous silicates, hydrolysis and condensation of silicon compounds, direct oxidation of silicon, and milling and peptization of silica powder. Various silica sols having particle sizes of 10-60 nm prepared by these methods and the preparation methods have been compared on the basis of their shape, size uniformity, sphericity, stability against pH variation, cation concentration, and price, etc. Silica sol prepared from tetraethoxysilane affords uniform size control and growth, and high purity, despite the relatively high costs. Silica sol prepared from liquid silicates affords relatively easy size and shape control; however, it is difficult to lower the alkali content to a level that is appropriate for carrying out semiconductor chemical mechanical polishing processes; in addition, the waste water treatment carried out for recovering the ion exchange resin gives rise environmental consideration. The properties of colloidal silica prepared from fumed silica powder by milling and dispersion depend on the starting silica source and it is relatively difficult to obtain monodispersed particles using this method. Colloidal silica prepared from silicon by direct oxidation has a monodispersed spherical shape and purity control with reasonable prices. It generates less waste water because it can be directly produced in relatively high concentrations. The cation fraction located in the particle relative to the free cation in the fluid is relatively lower in the silica sol prepared by the direct oxidation than others. A careful comparison of colloidal silica and the preparation methods may help in choosing the proper colloidal silica that is the most appropriate for the application being considered.
Management of Refractory Tracheal Collapse in a Dog using Self-Expanding Intraluminal Prosthesis
Seung-Gon Lee,Mi-Jung Kim,Changbaig Hyun
Journal of Animal and Veterinary Advances , 2012,
Abstract: Tracheal collapse is commonly seen in small breed dogs and is caused by a progressive weakening of the tracheal rings. A 5 year-old male Yorkshire terrier (weighing 1.97 kg) was presented Veterinary Teaching Hospital at Kangwon National University (S. Korea) with goose honking cough and cyanosis. On the radiographical and endoscopical examination, trachea was collapsed from the mid of cervical trachea to the mid of thoracic trachea. A self-expanding intraluminal stent (Zilver 635 biliary stents, COOK, USA) was implanted to restore collapsed trachea. After implantation, the dog was medicated with cough suppressant (methylephedrine, 2 mg kg 1 BID), prednisolone (0.5 mg kg 1 BID) and cefazoline (5 mg kg 1 BID) for 2 weeks, to reduce side effects from metallic stenting. Clinical improvement was noticed right after implantation. Although mild transient dry cough lasted for a month, the dog was clinically recovered from tracheal collapse.
Paraaortic lymph node metastasis in patients with intra-abdominal malignancies: CT vs PET
Mi-Jung Lee, Mi Jin Yun, Mi-Suk Park, Seung Hwan Cha, Myeong-Jin Kim, Jong Doo Lee, Ki Whang Kim
World Journal of Gastroenterology , 2009,
Abstract: AIM: To compare the diagnostic accuracy of computed tomography (CT) and positron emission tomography (PET) for the preoperative detection of paraaortic lymph node (PAN) metastasis in patients with intra-abdominal malignancies.METHODS: Sixty-six patients with intra-abdominal malignancies who underwent both CT and PET before lymphadenectomy were included in this study. Histopathologically, 13 patients had metastatic PAN, while 53 had non-metastatic PAN. The CT criteria for metastasis were: short diameter of > 8 mm, lobular or irregular shape, and/or combined ancillary findings, including necrosis, conglomeration, vessel encasement, and infiltration. The PET criterion was positive fluorodeoxyglucose (FDG) uptake. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of both modalities were compared with the pathologic findings, and the false positive and false negative cases with both CT and PET were analyzed.RESULTS: The sensitivity, specificity, PPV, NPV, and accuracy of CT were 61.5%, 84.9%, 50%, 90% and 80.3%, respectively. For PET, the percentages were 46.2%, 100%, 100%, 88.3%, and 89.4%. Additionally, there were 8 false positive CT cases (8/53, 15.1%) and zero false positive PET cases. Of the 13 metastatic PANs, there were 5 false negative CT scans (38.5%) and 7 (53.9%) false negative PET scans.CONCLUSION: For detecting PAN metastasis, CT is more sensitive than PET, while PET is more specific.
“Early Rupture of Membranes” during Induced Labor as a Risk Factor for Cesarean Delivery in Term Nulliparas
Seung Mi Lee, Jeong Woo Park, Chan-Wook Park, Bo Hyun Yoon
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039883
Abstract: Objective To determine if “early rupture of membranes” (early ROM) during induction of labor is associated with an increased risk of cesarean section in term nulliparas. Study Design The rate of cesarean section and the timing of ROM during the course of labor were examined in term singleton nulliparas whose labor was induced. Cases were divided into 2 groups according the timing of ROM: 1)“early ROM”, defined as ROM at a cervical dilatation<4 cm during labor; and 2) “late ROM”, ROM at a cervical dilatation≥4 cm during labor. Nonparametric techniques were used for statistical analysis. Results 1) In a total of 500 cases of study population, “early ROM” occurred in 43% and the overall cesarean section rate was 15.8%; 2) patients with “early ROM” had a higher rate of cesarean section and cesarean section due to failure to progress than did those with “late ROM” (overall cesarean section rate: 24%[51/215] vs. 10%[28/285], p<0.01; cesarean section rate due to failure to progress: 18%[38/215] vs. 8%[22/285], p<0.01 for each) and this difference remained significant after adjusting for confounding variables. Conclusion “Early ROM” during the course of induced labor is a risk factor for cesarean section in term singleton nulliparas.
Human Neural Stem Cells Genetically Modified to Overexpress Akt1 Provide Neuroprotection and Functional Improvement in Mouse Stroke Model
Hong J. Lee, Mi K. Kim, Hee J. Kim, Seung U. Kim
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0005586
Abstract: In a previous study, we have shown that human neural stem cells (hNSCs) transplanted in brain of mouse intracerebral hemorrhage (ICH) stroke model selectively migrate to the ICH lesion and induce behavioral recovery. However, low survival rate of grafted hNSCs in the brain precludes long-term therapeutic effect. We hypothesized that hNSCs overexpressing Akt1 transplanted into the lesion site could provide long-term improved survival of hNSCs, and behavioral recovery in mouse ICH model. F3 hNSC was genetically modified with a mouse Akt1 gene using a retroviral vector. F3 hNSCs expressing Akt1 were found to be highly resistant to H2O2-induced cytotoxicity in vitro. Following transplantation in ICH mouse brain, F3.Akt1 hNSCs induced behavioral improvement and significantly increased cell survival (50–100% increase) at 2 and 8 weeks post-transplantation as compared to parental F3 hNSCs. Brain transplantation of hNSCs overexpressing Akt1 in ICH animals provided functional recovery, and survival and differentiation of grafted hNSCs. These results indicate that the F3.Akt1 human NSCs should be a great value as a cellular source for the cellular therapy in animal models of human neurological disorders including ICH.
Correlation between psychological factors and the cerebellar volume of normal young adults
Chung Soon-Cheol,Choi Mi-Hyun,Lee Su-Jeong,Choi Jin-Seung
International Journal of Clinical and Health Psychology , 2010,
Abstract: Este estudio analiza la relación entre el volumen del cerebelo de adultos normales en la tercera década de la vida (20-29 a os) y varios factores psicológicos. El volumen del cerebelo de 118 sujetos (media de edad 23 ± 2,6 a os), incluyendo 58 varones (media de edad 24 ± 2,8 a os) y 60 mujeres (media de edad, 21,9 ± 2,1 a os), fue medido utilizando la imagen por resonancia magnética (IRM). Todos los participantes completaron los siguientes tests: Cuestionario de 90 Síntomas (SCL-90-R), Cuestionario de Personalidad de Tipo A, El cuestionario de Ansiedad Estado Korean YZ, El Cuestionario de 16 Factores de la Personalidad (16PF), y la Escala Autoadministrada de Depresión (EAD). Utilizando regresión linear, se analizó la relación entre el volumen del cerebelo y factores psicológicos. Sin considerar las diferencias entre géneros, en cuanto crecía la tendencia hacia la personalidad tipo A y se incrementaba el estado de ansiedad y la fuerza del superego, disminuía el volumen del cerebelo. Cuando se incrementaba la fuerza del ego, se incrementaba el volumen del cerebelo. Cuando se consideraban las diferencias de género, cuando incrementaba la ansiedad fóbica y ambición en varones, disminuía el volumen del cerebelo. En mujeres, cuando incrementaba la hostilidad, tensión y la ansiedad estado, disminuía el volumen del cerebelo.
Insulin Receptor-Overexpressing β-Cells Ameliorate Hyperglycemia in Diabetic Rats through Wnt Signaling Activation
Mi-Hyun Kim, Seung-Hyun Hong, Moon-Kyu Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067802
Abstract: To investigate the therapeutic efficacy and mechanism of β-cells with insulin receptor (IR) overexpression on diabetes mellitus (DM), rat insulinoma (INS-1) cells were engineered to stably express human insulin receptor (INS-IR cells), and subsequently transplanted into streptozotocin- induced diabetic rats. Compared with INS-1 cells, INS-IR cells showed improved β-cell function, including the increase in glucose utilization, calcium mobilization, and insulin secretion, and exhibited a higher rate of cell proliferation, and maintained lower levels of blood glucose in diabetic rats. These results were attributed to the increase of β-catenin/PPARγ complex bindings to peroxisome proliferator response elements in rat glucokinase (GK) promoter and the prolongation of S-phase of cell cycle by cyclin D1. These events resulted from more rapid and higher phosphorylation levels of insulin-signaling intermediates, including insulin receptor substrate (IRS)-1/IRS-2/phosphotylinositol 3 kinase/v-akt murine thymoma viral oncogene homolog (AKT) 1, and the consequent enhancement of β-catenin nuclear translocation and Wnt responsive genes including GK and cyclin D1. Indeed, the higher functionality and proliferation shown in INS-IR cells were offset by β-catenin, cyclin D1, GK, AKT1, and IRS-2 gene depletion. In addition, the promotion of cell proliferation and insulin secretion by Wnt signaling activation was shown by 100 nM insulin treatment, and to a similar degree, was shown in INS-IR cells. In this regard, this study suggests that transferring INS-IR cells into diabetic animals is an effective and feasible DM treatment. Accordingly, the method might be a promising alternative strategy for treatment of DM given the adverse effects of insulin among patients, including the increased risk of modest weight gain and hypoglycemia. Additionally, this study demonstrates that the novel mechanism of cross-talk between insulin and Wnt signaling plays a primary role in the higher therapeutic efficacy of IR-overexpressing β-cells.
Dynamic correlations between heart and brain rhythm during Autogenic meditation
Dae-Keun Kim,Kyung-Mi Lee,Jongwha Kim,Seung Wan Kang
Frontiers in Human Neuroscience , 2013, DOI: 10.3389/fnhum.2013.00414
Abstract: This study is aimed to determine significant physiological parameters of brain and heart under meditative state, both in each activities and their dynamic correlations. Electrophysiological changes in response to meditation were explored in 12 healthy volunteers who completed 8 weeks of a basic training course in autogenic meditation. Heart coherence, representing the degree of ordering in oscillation of heart rhythm intervals, increased significantly during meditation. Relative EEG alpha power and alpha lagged coherence also increased. A significant slowing of parietal peak alpha frequency was observed. Parietal peak alpha power increased with increasing heart coherence during meditation, but no such relationship was observed during baseline. Average alpha lagged coherence also increased with increasing heart coherence during meditation, but weak opposite relationship was observed at baseline. Relative alpha power increased with increasing heart coherence during both meditation and baseline periods. Heart coherence can be a cardiac marker for the meditative state and also may be a general marker for the meditative state since heart coherence is strongly correlated with EEG alpha activities. It is expected that increasing heart coherence and the accompanying EEG alpha activations, heart brain synchronicity, would help recover physiological synchrony following a period of homeostatic depletion.
Theory of fads: Traveling-wave solution of evolutionary dynamics in a one-dimensional trait space
Mi Jin Lee,Su Do Yi,Beom Jun Kim,Seung Ki Baek
Physics , 2015, DOI: 10.1103/PhysRevE.91.012815
Abstract: We consider an infinite-sized population where an infinite number of traits compete simultaneously. The replicator equation with a diffusive term describes time evolution of the probability distribution over the traits due to selection and mutation on a mean-field level. We argue that this dynamics can be expressed as a variant of the Fisher equation with high-order correction terms. The equation has a traveling-wave solution, and the phase-space method shows how the wave shape depends on the correction. We compare this solution with empirical time-series data of given names in Quebec, treating it as a descriptive model for the observed patterns. Our model explains the reason that many names exhibit a similar pattern of the rise and fall as time goes by. At the same time, we have found that their dissimilarities are also statistically significant.
Evolution of popularity in given names
Mi Jin Lee,Woo Seong Jo,Il Gu Yi,Seung Ki Baek,Beom Jun Kim
Physics , 2015, DOI: 10.1016/j.physa.2015.09.076
Abstract: An individual's identity in a human society is specified by his or her name. Differently from family names, usually inherited from fathers, a given name for a child is often chosen at the parents' disposal. However, their decision cannot be made in a vacuum but affected by social conventions and trends. Furthermore, such social pressure changes in time, as new names gain popularity while some other names are gradually forgotten. In this paper, we investigate how popularity of given names has evolved over the last century by using datasets collected in Korea, the province of Quebec in Canada, and the United States. In each of these countries, the average popularity of given names exhibits typical patterns of rise and fall with a time scale of about one generation. We also observe that notable changes of diversity in given names signal major social changes.
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