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철근콘크리트 연속보에서 부분프리스트레스 도입에 의한 휨보강 효과에 관한 연구
한병찬,윤현도,박완신,황선경,임재형,문정호 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)
A strengthening technique for reinforced concrete beams using external unbonded reinforcement offers advantages in speed and simplicity of installation over other, established, strengthening techniques. The purpose of this paper is to investigate the capabilities of a new retrofitting technique, namely external prestressing(Bow), for flexural strengthening of beams. The paper provides a general description of structural behavior of beams strengthened using the technique. Results of 2 physical tests on strengthened reinforced concrete continuous beams are reported and compared. It is shown that the technique can provide greater strength enhancement to lightly reinforced sections and that provision of deflectors enhances efficiency.
교류전해에칭용 에틸렌글리콜의 알루미늄박판의 부식억제 효과
박성민, 양정진, 김홍일, 김한주, 김성한, 신진식, 박수길 충북대학교 건설기술연구소 2008 충북대학교 건설기술연구소 논문집 Vol.27 No.1
In this study, additions of aluminium foil eching characteristics were compared with sulfuric acid for capacitor. sulfuric acid and ethylene glycol is used as addition, characteristics of funtional group from addition were guessed by comparing of aluminium foil eching characteristics. When sulfuric acid was added in HCI etching solution, corrosion of aluminum metal was inhibited by the chemical adsorption of sulfate ion, when ethylen glycol was added in HCI etching solution, corrosion inhibited by the chemical adsorption of OH^ion.
Lee, Mi Nam,Hwang, Hee-Su,Oh, Sin-Hye,Roshanzadeh, Amir,Kim, Jung-Woo,Song, Ju Han,Kim, Eung-Sam,Koh, Jeong-Tae Nature Publishing Group UK 2018 Experimental and molecular medicine Vol.50 No.11
<▼1><P>Supplementation of mesenchymal stem cells (MSCs) at sites of bone resorption is required for bone homeostasis because of the non-proliferation and short lifespan properties of the osteoblasts. Calcium ions (Ca<SUP>2+</SUP>) are released from the bone surfaces during osteoclast-mediated bone resorption. However, how elevated extracellular Ca<SUP>2+</SUP> concentrations would alter MSCs behavior in the proximal sites of bone resorption is largely unknown. In this study, we investigated the effect of extracellular Ca<SUP>2+</SUP> on MSCs phenotype depending on Ca<SUP>2+</SUP> concentrations. We found that the elevated extracellular Ca<SUP>2+</SUP> promoted cell proliferation and matrix mineralization of MSCs. In addition, MSCs induced the expression and secretion of osteopontin (OPN), which enhanced MSCs migration under the elevated extracellular Ca<SUP>2+</SUP> conditions. We developed in vitro osteoclast-mediated bone resorption conditions using mouse calvaria bone slices and demonstrated Ca<SUP>2+</SUP> is released from bone resorption surfaces. We also showed that the MSCs phenotype, including cell proliferation and migration, changed when the cells were treated with a bone resorption-conditioned medium. These findings suggest that the dynamic changes in Ca<SUP>2+</SUP> concentrations in the microenvironments of bone remodeling surfaces modulate MSCs phenotype and thereby contribute to bone regeneration.</P></▼1><▼2><P><B>Bone formation: released calcium could stimulate stem cells</B></P><P>Studies with mouse cells and bone samples indicate how calcium ions released during the normal turnover of bone promote the supplementation of stem cells needed to make new bone during routine “remodeling” and regeneration after injury. Our bones are degraded and remodeled continuously, requiring the controlled supplement of stem cells that create bone-forming cells called osteoblasts. Jeong-Tae Koh and colleagues at Chonnam National University, Gwangju, South Korea, exposed the relevant stem cells to increased concentrations of external calcium ions. This promoted cell proliferation and migration that allow the cells to support new bone formation. The research suggests this effect on stem cells may be achieved by calcium ions released directly from bone as it is naturally degraded. The findings may help researchers develop new ways to encourage bone regeneration after injury and surgery.</P></▼2>
최석천,이용훈,전유신,허선철,정효민,정한식 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
The purpose of this research is to obtain the characteristics of strain and stress in the vacuum pressure vessel. The vacuum pressure vessel is used to many of industrial devices and cooling tower system. The vessel is under the vacuum pressure in this research, and we analyzed the stress on the vessel surface. As the experimental set up, we introduced the Static Strain Measurement(UCAM 70A, Kyowa) system. The environmental condition of vessel is reserved under vacuum pressure 50mmHg, and the vacuum pressure was made by a ejector pump system.
서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)
김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1
In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.
Investigation of the Lack of Angiogenesis in the Formation of Lymph Node Metastases
Jeong, Han-Sin,Jones, Dennis,Liao, Shan,Wattson, Daniel A.,Cui, Cheryl H.,Duda, Dan G.,Willett, Christopher G.,Jain, Rakesh K.,Padera, Timothy P. U.S. Dept. of Health, Education, and Welfare, Publ 2015 Journal of the National Cancer Institute Vol.107 No.9
<P><B>Background:</B></P><P>To date, antiangiogenic therapy has failed to improve overall survival in cancer patients when used in the adjuvant setting (local-regional disease with no detectable systemic metastasis). The presence of lymph node metastases worsens prognosis, however their reliance on angiogenesis for growth has not been reported.</P><P><B>Methods:</B></P><P>Here, we introduce a novel chronic lymph node window (CLNW) model to facilitate new discoveries in the growth and spread of lymph node metastases. We use the CLNW in multiple models of spontaneous lymphatic metastases in mice to study the vasculature of metastatic lymph nodes (n = 9–12). We further test our results in patient samples (n = 20 colon cancer patients; n = 20 head and neck cancer patients). Finally, we test the ability of antiangiogenic therapy to inhibit metastatic growth in the CLNW. All statistical tests were two-sided.</P><P><B>Results:</B></P><P>Using the CLNW, we reveal the surprising lack of sprouting angiogenesis during metastatic growth, despite the presence of hypoxia in some lesions. Treatment with two different antiangiogenic therapies showed no effect on the growth or vascular density of lymph node metastases (day 10: untreated mean = 1.2%, 95% confidence interval [CI] = 0.7% to 1.7%; control mean = 0.7%, 95% CI = 0.1% to 1.3%; DC101 mean = 0.4%, 95% CI = 0.0% to 3.3%; sunitinib mean = 0.5%, 95% CI = 0.0% to 1.0%, analysis of variance <I>P</I> = .34). We confirmed these findings in clinical specimens, including the lack of reduction in blood vessel density in lymph node metastases in patients treated with bevacizumab (no bevacizumab group mean = 257 vessels/mm<SUP>2</SUP>, 95% CI = 149 to 365 vessels/mm<SUP>2</SUP>; bevacizumab group mean = 327 vessels/mm<SUP>2</SUP>, 95% CI = 140 to 514 vessels/mm<SUP>2</SUP>, <I>P</I> = .78).</P><P><B>Conclusion:</B></P><P>We provide preclinical and clinical evidence that sprouting angiogenesis does not occur during the growth of lymph node metastases, and thus reveals a new mechanism of treatment resistance to antiangiogenic therapy in adjuvant settings. The targets of clinically approved angiogenesis inhibitors are not active during early cancer progression in the lymph node, suggesting that inhibitors of sprouting angiogenesis as a class will not be effective in treating lymph node metastases.</P>
Imaging of Facial Nerve With 3D-DESS-WE-MRI Before Parotidectomy: Impact on Surgical Outcomes
Jeong Han-Sin,Kim Yikyung,Kim Hyung-Jin,Kim Hak Jung,Kim Eun-hye,Woo Sook-young,Chung Man Ki,Son Young-Ik 대한영상의학회 2023 Korean Journal of Radiology Vol.24 No.9
Objective: The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state waterexcitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI. Materials and Methods: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESSWE- MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. Results: The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESSWE- MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64–8.25] and 2.02 [95% CI: 0.32–12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19–16.75] and 1.94 [95% CI: 0.20–18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). Conclusion: Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.