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殘留應力을 考慮한 鎔接材의 疲勞龜裂 進展擧動에 關한 硏究
최병기,이을호,국중민,기준호,임선빈,정장만 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1
The effect of welding residual stress on the initiation and propagation of fatigue crack is investigated so as to study the fatigue behavior in welding residual stress field. Especially, the relation between welding residual stress and fatigue crack opening behavior is investigated and the redistribution of residual stress as a fatigue crack propagates is examined. Following results are obtained. 1) In case of the load range is constant, as the stress ratio is changing to 0.1, 0.33, 0.5 the propagation life is constant but the growth life decreases. And than, when maximum load or minimum load is constant, as the stress ratio increases the growth life and propagation life increase. 2) The fatigue crack propagations rate da/dN appears to accelerate when the stress intensity factor range ΔK is less than 15MPa-m^1/2. 3) The residual stress that is appeared by welding decreases after cutting. 4) Fatigue crack propagation ratio is affected by tensional and compressible residual stress at the initial time, but it's similar to the original in the more than 20mm of crack length.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
Redd1 (known as RTP801/Dig2/DDIT4) is a stress-induced protein, and it is known to be regulated in response to some stresses including hypoxia and oxidative stress. In the present study, we investigated the time-course changes in Redd1 immunoreactivity and its protein levels in the gerbil hippocampus proper (CA1-3 regions) after 5 min of transient global cerebral ischemia using immunohistochemistry and western blot analysis. Redd1 immunoreactivity was apparently changed in the pyramidal neurons of the ischemic CA1 region, not the ischemic CA2/3 region. Redd1 immunoreactivity in the CA1 pyramidal neurons was significantly increased at 6 h post-ischemia, decreased until 1 day postischemia, increased again at 2 days post-ischemia and weakly observed at 5 days post-ischemia. Especially, at 5 days after ischemic damage, Redd1 immunoreactivity was newly expressed in astrocytes and GABAergic interneurons in the CA1 region. Redd1 protein levels in the ischemic CA1 region were changed like the pattern of the Redd1 immunoreactivity. These results indicate that Redd1 immunoreactivity and protein levels are increased in the ischemic CA1 region at early time after ischemic damage and that the increased Redd1 expression may be closely related to the delayed neuronal death of the CA1 pyramidal neurons following 5 min of transient global cerebral ischemia.
Newly Developed Multiple Myeloma in a Patient with Primary T-Cell Lymphoma of Bone
Jun Eul Hwang,조상희,Ok Ki Kim,Hyun Jeong Shim,Se Ryeon Lee,Jae Sook Ahn,양덕환,김여경,이제중,김형준,정익주 대한의학회 2008 Journal of Korean medical science Vol.23 No.3
Primary non-Hodgkin’s lymphoma of bone (PLB) is rare, and generally presents as a single extensive and destructive bone lesion. Histopathologically, most cases present as diffuse large B-cell lymphoma, and T-cell lymphoma is rare. By contrast, multiple myeloma is a disease defined as the neoplastic proliferation of a single clone of plasma cells producing a monoclonal immunoglobulin. We report a case of multiple myeloma that developed during treatment of PLB in a type of T-cell. A 48-yr-old man was diagnosed as T-cell PLB, stage IE, 18 months ago. The patient received the chemoradiotherapy and salvage chemotherapy for PLB. However, the lymphoma progressed with generalized bone pain, and laboratory findings showed bicytopenia and acute renal failure. On bone marrow biopsy, the patient was diagnosed as having multiple myeloma newly developed with primary T-cell lymphoma of bone. In spite of chemotherapy, the patient died of renal failure.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
Obesity induced by high-fat diet (HFD) is one of the most widespread metabolic disorders in current society. However, there has been little study regarding the effects of HFD induced obesity in the septum of animal models of cerebral ischemia. Therefore, in the present study, we investigated effects of HFD on neuronal damage and gliosis in the septum induced by transient cerebral ischemia. Body weight, blood glucose levels and serum lipid profiles levels were measured both in the normal diet (ND) and HFD-group. And, we also investigated the effects of ND and HFD on neuronal damage and gliosis in the septum after transient cerebral ischemia using immunohistochemistry. The levels of blood glucose, serum triglyceride and total cholesterol were significantly increased in the HFD-fed gerbils compared with the ND-fed gerbils, although body weight was not significantly changed after HFD feeding. In the ND-fed gerbils, ischemia-induced neuronal damage was found in the septo-hippocampal nucleus (SHN) of the septum 7 days after ischemia. In the HFD-fed gerbils, ischemia-induced neuronal damage in the SHN was much severer compared with the ND-fed gerbils 4 and 7 days after ischemia. In addition, we found that ischemia-induced glial activation including astrocytes and microglia was accelerated and exacerbated in the HFD-fed gerbils compared with that in the ND-fed gerbils. These results indicate that HFD can lead to much exacerbated effects in ischemia-induced neuronal damage/death in the septum after ischemia-reperfusion and that it may be associated with accelerated change in glial activation.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
Tanshinone I (TsI) is an important lipophilic diterpene extracted from Danshen (Radix Salvia miltiorrhizae) and has been used in Asia for the treatment of cerebrovascular diseases such as ischemic stroke. In this study, we examined the neuroprotective effect of tanshinone I (TsI) against ischemic damage and its neuroprotective mechanism in the gerbil hippocampal CA1 region (CA1) induced by 5 min of transient global cerebral ischemia. Pre-treatment with TsI protected pyramidale neurons from ischemic damage in the stratum pyramidale of the CA1 after ischemiareperfusion. The pre-treatment with TsI increased the immunoreactivities and protein levels of anti-inflammatory cytokines (interleukin (IL)-4 and IL- 13) in the TsI-treated-sham-operated-groups compared with those in the vehicle-treated-sham-operated-groups; however, the treatment did not increase the immunoreactivities and protein levels of pro-inflammatory cytokines (IL-2 and tumor necrosis factor (TNF)-α). On the other hand, in the TsI-treated-ischemia-operated-groups, the immunoreactivities and protein levels of all the cytokines were maintained in the stratum pyramidal of the CA1 after transient ischemia. In conclusion, these findings indicate that the pre-treatment with TsI can protect against ischemia-induced neuronal death in the CA1 via the increase or maintenance of inflammatory cytokines.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
5-hydroxytryptamine (5-HT, serotonin) plays protective or detrimental roles in the development of ischemic damage. In the present study, we investigated the time-course changes in 5-HT1A receptor protein expression in the gerbil hippocampal CA1 region after transient global cerebral ischemia via immunohistochemistry and western blot analysis. 5-HT1A receptor immunoreactivity in the stratum pyramidale (SP) of the hippocampal CA1 region was decreased from 6 h, and hardly observed at 1 day and 2 days after ischemic damage. At 5 days and 10 days after ischemia-reperfusion, 5-HT1A receptor immunoreactivity was increased and detected newly in astrocyte of the ischemic CA1 region. The pattern of changes in 5-HT1A receptor protein levels in the hippocampal CA1 region after ischemia-reperfusion was similar to that observed in the immunohistochemical data. These results indicate that 5-HT1A receptor protein expressions may be related with the ischemia-induced neuronal death and the function of astrocyte in the ischemic hippocampal CA1 region.
Jun Eul Hwang,Ju-Young Yoon,Woo Kyun Bae,Hyun Jeong Shim,Ik Joo Chung 대한부인종양학회 2012 Journal of Gynecologic Oncology Vol.23 No.1
Cancers of an unknown primary site are heterogenous with respect to their clinical and pathologic features. They are generally very aggressive, but specific favorable subsets have a better prognosis. For these favorable subsets, taxane based chemotherapy is very effective for a subset of woman with papillary serous peritoneal adenocarcinoma. A 52 year-old woman underwent [^(18)F]- FDG PET/CT for routine health screening. On PET/CT, multiple hypermetabolic lymph nodes were detected in the paraaortic spaces, and there were no other hypermetabolic abnormalities. The patient was diagnosed with an unknown primary cancer that probably originated from the ovary or peritoneum, according to clinical studies and biopsy results. This was not a typical case of a favorable subset of cancer of an unknown primary site, but the tumor showed complete biologic response to taxane based chemotherapy as revealed by PET/CT, and necrotic tumor cells were confirmed by surgery.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
The receptor for advanced glycation end products (RAGE) is a multi-ligand receptor of the immunoglobulin superfamily that has been implicated in multiple neuronal and inflammatory stress processes. In the present study, we investigated changes in RAGE immunoreactivity and its protein levels in the gerbil hippocampus (CA1-3 regions) after 5 min of transient global cerebral ischemia. The ischemic hippocampus was stained with cresyl violet (CV), NeuN (a neuron-specific soluble nuclear antigen) antibody and Fluro-Jade B (a marker for neuronal degeneration). Five days after ischemia-reperfusion, delayed neuronal death occurred in the stratum pyramidale (SP) of the CA1 region. RAGE immunoreactivity was not detected in any regions of the CA1-3 regions of the sham-group. RAGE immunoreactivity was detected only in the CA1 region from 3 days post-ischemia, and the RAGE immunoreactivity was newly expressed in astrocytes, not in neurons. In addition, the level of RAGE protein was highest at 5 days post-ischemia. In brief, both the RAGE immunoreactivity and protein level were distinctively increased in astrocytes in the ischemic CA1 region from 3 days after transient cerebral ischemia. These results indicate that the increase of RAGE expression in astrocytes at post-ischemia may be related to the ischemia-induced activation of astrocytes in the ischemic CA1 region.
( Jun Hwi Cho ),( Chan Woo Park ),( Myoung Chul Shin ),( Taek Geun Ohk ),( Joon Ho Bae ),( Dae Jin Jeong ),( Jun Yeol Lee ),( Ka Eul Kim ),( Ki Joong Kim ),( Doo Hyun Lee ),( Jung Hoon Lee ),( Moo Ho 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2
Hydroquinone (HQ) occurs naturally in various plants and food, and is also manufactured for commercial use. Recently, it has been reported that HQ has potent antioxidant properties with radical scavenging activities. In this study, the neuroprotective effect of HQ against ischemic damage following transient focal and global ischemia was examined using 2,3,5-triphenyltetrazoliumchloride (TTC) staining, NeuN immunohistochemistry and F-J B histofluorescence. Fig. It was proven that pre- and post-treatment with 100 mg/kg of HQ protects neurons from ischemic damage. In addition, we also investigated effects of HQ on gliosis and endogenous antioxidants in the hippocampal CA1 region after transient cerebral ischemia using immunohistochemistry. Pre- and post-treatment with 100 mg/kg of HQ notably inhibited the glial activation and maintained the expression of endogenous antioxidants in the gerbil ischemic CA1 region. Briefly, these results indicate that pre- and post-treatment with HQ can protect against ischemic damage induced by transient focal and global ischemia, and the neuroprotective effects of HQ may be closely associated with the attenuation of glial activation and the maintenance of the expression of endogenous antioxidants.