• International Journal of Naval Architecture and Ocean Engineering
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• 제4권1호
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• pp.57-70
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• 2012

This article presents a numerical investigation concerning the effect of two kinds of axially progressing internal flows (namely, upward and downward) on fluid.structure interaction (FSI) dynamics about a marine riser model which is subject to external shear current. The CAE technology behind the current research is a proposed FSI solution, which combines structural analysis software with CFD technology together. Efficiency validation for the CFD software was carried out first. It has been proved that the result from numerical simulations agrees well with the observation from relating model test cases in which the fluidity of internal flow is ignorable. After verifying the numerical code accuracy, simulations are conducted to study the vibration response that attributes to the internal progressive flow. It is found that the existence of internal flow does play an important role in determining the vibration mode (/dominant frequency) and the magnitude of instantaneous vibration amplitude. Since asymmetric curvature along the riser span emerges in the case of external shear current, the centrifugal and Coriolis accelerations owing to up- and downward internal progressive flows play different roles in determining the fluid.structure interaction response. The discrepancy between them becomes distinct, when the velocity ratio of internal flow against external shear current is relatively high.

• Wind and Structures
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• 제28권6호
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• pp.389-404
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• 2019

In coastal regions, it is common to witness significant damages on low-rise buildings caused by hurricanes and other extreme wind events. These damages start at high pressure zones or weak building components, and then cascade to other building parts. The state-of-the-art in experimental and numerical aerodynamic load evaluation is to assume buildings with intact envelopes where wind acts only on the external walls and correct for internal pressure through separate aerodynamic studies. This approach fails to explain the effect of openings on (i) the external pressure, (ii) internal partition walls; and (iii) the load sharing between internal and external walls. During extreme events, non-structural components (e.g., windows, doors or rooftiles) could fail allowing the wind flow to enter the building, which can subject the internal walls to lateral loads that potentially can exceed their load capacities. Internal walls are typically designed for lower capacities compared to external walls. In the present work, an anticipated damage development scenario is modelled for a four-story building with a stepped gable roof. LES is used to examine the change in the internal and external wind flows for different level of assumed damages (starting from an intact building up to a case with failure in most windows and doors are observed). This study demonstrates that damages in non-structural components can increase the wind risk on the structural elements due to changes in the loading patterns. It also highlights the load sharing mechanisms in low rise buildings.

• Interaction and multiscale mechanics
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• 제5권2호
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• pp.157-168
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• 2012

The dilatancy of granular materials has significant influence on its mechanical behaviors. The dilation angle is taken as a constant in conventional associated or non-associated flow rules based on Drucker-Prager yields theory. However, various experimental results show the dilatancy changes during progressive failure of granular materials. A non-associated flow rule with evolution of dilation angle is adopted in this study, and Cosserat continuum theory is used to describe the behaviors of granular materials for considering to some extent the its internal structure. Numerical examples focus on the bearing capacity and localization of granular materials, and results illustrate the capability and performance of the presented model in modeling the effect on failure behavior of granular materials.

• 대한수의학회지
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• 제63권4호
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• pp.38.1-38.6
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• 2023

Canine T-zone lymphoma (TZL) is an indolent form of T-cell lymphoma. Conservative management is usually recommended; however, chemotherapy may be considered for symptomatic or progressive cases. Herein, we describe two dogs with generalized peripheral lymphadenopathy and peripheral blood lymphocytosis at presentation. One dog presented with gross lesions on the tongue. Flow cytometric immunophenotyping and cytological examinations demonstrated findings consistent with those of TZL. Chemotherapy with chlorambucil and prednisolone was administered, which resulted in improvement of the condition without any adverse events. Chemotherapy with chlorambucil may be considered as an appropriate choice for treating canine TZL.

• International Journal of Stem Cells
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• 제17권1호
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• pp.30-37
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• 2024

The lung is a complex organ comprising a branched airway that connects the large airway and millions of terminal gas-exchange units. Traditional pulmonary biomedical research by using cell line model system have limitations such as lack of cellular heterogeneity, animal models also have limitations including ethical concern, race-to-race variations, and physiological differences found in vivo. Organoids and on-a-chip models offer viable solutions for these issues. Organoids are three-dimensional, self-organized construct composed of numerous cells derived from stem cells cultured with growth factors required for the maintenance of stem cells. On-a-chip models are biomimetic microsystems which are able to customize to use microfluidic systems to simulate blood flow in blood channels or vacuum to simulate human breathing. This review summarizes the key components and previous biomedical studies conducted on lung organoids and lung-on-a-chip models, and introduces potential future applications. Considering the importance and benefits of these model systems, we believe that the system will offer better platform to biomedical researchers on pulmonary diseases, such as emerging viral infection, progressive fibrotic pulmonary diseases, or primary or metastatic lung cancer.

• 대한한방내과학회지
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• 제26권2호
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• pp.310-319
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• 2005

Objectives: The aim is to identify any anti-tumor effects of Duchesnea indica(Andr.) Focke on colon cancer cells. Materials & Methods: Colo201 human adenocarcinoma cells were obtained from American Type Culture Collection. The boiled extract of Duchesnea indica(Andr.) Focke was added (10 and 20 microliters) to cultures and observed at 0, 6, and 12 hours, and at 12-hour intervals thereafter. Morphological changes in colon cancer cells were observed through an inverted microscope, Destruction of colon cancer cells was measured through Trypan blue exclusion testing. Suppression of the viability of colon cancer cells were measured via MTT assay. Anti-cancer mechanisms in the cell cycle of colon cancer cells were analysed via flow cytometry. Results: After introduction of Duchesnea indica(Andr.) Focke to cultures several changes were seen. Significant atrophy of the nucleus and cytoplasm of colon cancer cells was observed, indicating cell injury. Destruction of colon cancer cells was observed in direct proportion to dosage and duration. Suppression of viability of colon cancer cells for each test group was greater than that of the control group increasingly over time(36h, 48h, 60h, 72h), which was statistical significant (p<0.05). Cell numbers of the mitosis phase of the colon cancer cell cycle reduced. Conclusions: Statistcally significant anti-tumor effects of Duchesnea indica(Andr.) Focke were observed in this in vitro experiment. Results support a role for Duchesnea indica(Andr.) Focke in treatment of colon cancer. though it will required progressive research to develop a practical treatment.

• Journal of Korean Neurosurgical Society
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• 제62권2호
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• pp.136-143
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• 2019

Moyamoya disease (MMD) is a progressive cerebrovascular disease with unknown etiology, characterized by bilateral steno-occlusive changes at the terminal portion of the internal carotid artery and an abnormal vascular network formation at the base of the brain. MMD has an intrinsic nature to convert the vascular supply for the brain from internal carotid (IC) system to the external carotid (EC) system, as indicated by Suzuki's angiographic staging. Insufficiency of this 'IC-EC conversion system' could result not only in cerebral ischemia, but also in intracranial hemorrhage from inadequate collateral anastomosis, both of which represent the clinical manifestation of MMD. Surgical revascularization prevents cerebral ischemic attack by improving cerebral blood flow, and recent evidence further suggests that extracranial-intracranial bypass could powerfully reduce the risk of re-bleeding in MMD patients with posterior hemorrhage, who were known to have extremely high re-bleeding risk. Although the exact mechanism underlying the hemorrhagic presentation in MMD is undetermined, most recent angiographic analysis revealed the characteristic angio-architecture related to high re-bleeding risk, such as the extension and dilatation of choroidal collaterals and posterior cerebral artery involvement. We sought to update the current management strategy for hemorrhagic MMD, including the outcome of surgical revascularization for hemorrhagic MMD in our institute. Further investigations will clarify the optimal surgical strategy to prevent hemorrhagic manifestation in patients with MMD.

• 대한한방내과학회지
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• 제23권1호
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• pp.99-106
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• 2002

Background : Nowadays a lot of research is based on natural substances or materials world wide since many kinds of side effects are accompanied by anti tumor chemotherapy. In Chinese medicine, Dioscorea bulbifera L is widely used to treat many kinds of cancer, but in Korea it is rarely used. Therefore, we need to scientifically identify anti tumor effects of Dioscorea bulbifera L. Objective : We aimed to identify anti tumor effects of Dioscorea bulbifera L on the stomach cancer cells through molecular biological methods. Materials & Methods : We used AGS, a stomach cancer cell from American Type Culture Collection. We injected the boiled extract of Dioscorea bulbifera L 5 ul(sample 1), 10ul(sample 2) to cultured media(ml) for 0,6,12,18,24 hours. We measured the killing effect on stomach cancer cells through Tryphan blue exclusion test and suppressive effect on viability of stomach cancer cells via MTT assay. Results : Tryphan blue exclusion test showed that each test group killed more stomach cancer cells than the controlled group with a dosage-dependent, but not significantly. MTT assay showed that each test group had a more suppressive effect on viability of stomach cancer cells than the controlled group without a dosage-independent, but not significantly. The cell cycle analysis via flow cytometry showed that the test group extended cell cycle, and there was no peak in M phase, the number of sub G1, G0, G1 phase cells increased a little, but not significantly. Conclusion : This experiment showed that Dioscorea bulbifera L. has an anti-tumor effect, but not significantly. This is in vitro experiment and basic experiment on Dioscorea bulbifera L. We hope more progressive researches on Dioscorea bulbifera L. will be conducted and its anti tumor will be more accurately identified.

• 대한한방내과학회지
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• 제24권2호
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• pp.290-299
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• 2003

Background : Nowadays many researches about it s cure are going on world widely since cancer is one of the most human health threatening diseases. In Chinese and North Korean medicine, Duchesnea india(Audra.) Foche. is practically used to treat many kinds of cancer, but in Korea it is rarely used. So, we need to scientifically identify anti-tumor effects of Duchesnea india(Audra.) Foche. Objective : We are aimed to identify anti-tumor effects of Duchesnea india(Audra.) Foche. on the stomach cancer cells through molecular biologic methods. Material & Methods : We used AGS as stomach cancer cells from American Type Culture Collection. We added the boiled extract of Duchesnea india(Audra.) Foche. $5{\mu}l$(Sample I), $10{\mu}l$(Sample II) to cultural media(ml)for 0,6, 12, 24, 48 hours. We measured the killing effect on stomach cancer cells through Tryphan blue exclusion test and the suppressive effect on viability of stomach cancer cells via MTT assay. the quantitative RT-PCR was used to examine their effect on the revelation of Bcl-2, Bcl-XL, and Bax, which are genes related to apoptosis. We measured change of mitochondria membrane permeability and membrane potential via flow cytometry. Result : 1. The killing effect on stomach cancer cells showed that each test groups killed more stomach cancer cells than the control group with a time(6 hours later) and density dependent manner, which was statistical significance. 2. The suppressive effect on viability of stomach cancer cells showed that each test groups had more suppressive effects on viability of stomach cancer cells than the control group with a time(6 hours later), which was statistical significance. 3. In the test about the revelation of genes related to apoptosis, the revelation of Bcl-2 and Bcl-XL decreased with a density manner which was statistical significance. but the revelation of Bax was not changed with statistical significance. 4. As a result of this test, Duchesnea india(Audra.) Foche. caused apoptosis by decreasing the absorbance of mitochondria with statistical significance. and also induced apoptosis by decreasing the membrane potential of mitochondria. Conclusion : This experiment showed that Duchesnea india(Audra.) Foche. has anti-tumor effect with statistical significance. This is in vitro experiment and basic experiment on Duchesnea india(Audra.) Foche. We hope more progressive researchs on Duchesnea india(Audra.) Foche. will go on and its anti-tumor effects will be more practically identified.

• 대한한방종양학회지
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• 제9권1호
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• pp.15-37
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• 2003

Objective: We are aimed to identify anti-tumor effects of Curcuma longa L. on the stomach cancer cells through molecular biologic methods. Material & Methods: We used AGS as human stomach cancer cells obtained from American Type Culture Collection. The boiled extract of Curcuma longa L. $5{\mu}l$ (Sample I), $10{\mu}l$ (Sample II) was treated to cultural media(ml) for 0, 6, 12, 24, 48 hours. We measured the killing effect on stomach cancer cells through Trypan blue exclusion test and the suppressive effect on viability of stomach cancer cells via MTT assay. For identification of its anticancer mechanism, the revelation of Bcl-2, Bcl-XL, and Bax which are genes related to apoptosis using the quantitative RT-PCR, change of mitochondria membrane permeability and membrane potential via flow cytometry, the cycle of cell mitosis, caspase cleavage and annexin V staining were examined. Results: 1. showed significant killing effect on stomach cancer cell than the control group with a time(6 hours later) and density dependent manner, which was statistical significance. 2. Extract of Curcuma longa L. showed suppressive effect on viability of stomach cancer cells that each test groups had more suppressive effects on viability of stomach cancer cells than the control group with a time(6 hours later), which was statistical significance.(p<0.05) 3. In the test about the revelation of genes related to apoptosis, the revelation of Bcl-2 and Bcl-XL decreased with a density manner which was statistical significance. but the revelation of Bax was not changed with statistical significance. 4. Extract of Curcuma longa L. caused apoptosis by decreasing the absorbance of mitochondria with statistical significance, and also induced apoptosis by decreasing the membrane potential of mitochondria. 5. Extract of Curcuma longa L. destructed the cell cycle of cell mitosos. 6. Cell apoptosis was induced by extract of Curcuma longa L. certificated by method of caspase cleavage and annexin V staining. Conclusion: This experiment showed that Curcuma longa L. has anti-tumor effect with statistical significance. This is in vitro experiment and basic experiment on Curcuma longa L.. We hope more progressive research on Curcuma longa L. will go on and its anti-tumor effects will be more practically identified.