• 한국안전학회지
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• 제7권1호
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• pp.47-56
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• 1992

Spontaneous ignition charactenstics for fish meal were observed by performing experiments at constant ambient temperature and varying the ambient temperature sinusoidally. As the results of the experiments at a constant ambient temperature, the critical spontaneous ignition temperature of the sample for large, intermediate and small vessels was 170.5$^{\circ}C$, 177.5$^{\circ}C$ and 188.5$^{\circ}C$, respectively. The critical spontaneous ignition temperature decreased as the sample vessel size increased. Apparent activation energy of used fish meal calculated from the Frank-Kamenetskii's thermal ignition theory was 37.60Kcal/mol. In case of varying the ambient temperature sinusoidally, the amplitudes of temperature were 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$ respectively with the period in each amplitude 1hr, 2hrs and 3hrs. The results showed that the critical spontaneous ignition temperatures at the varied amplitudes of temperature were lower than that at the constant anbient temperature and increased as the amplitude increased. At the same amplitude, the critical spontaneous ignition temperature increased with the period.

• Journal of Chest Surgery
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• 제55권4호
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• pp.325-331
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• 2022

Postoperative critical care management for lung transplant recipients in the intensive care unit (ICU) has expanded in recent years due to its complexity and impact on clinical outcomes. The practical aspects of post-transplant critical care management, especially regarding ventilation and hemodynamic management during the early postoperative period in the ICU, are discussed in this brief review. Monitoring in the ICU provides information on the patient's clinical status, diagnostic assessment of complications, and future management plans since lung transplantation involves unique pathophysiological conditions and risk factors for complications. After lung transplantation, the grafts should be appropriately ventilated with lung protective strategies to prevent ventilator-induced lung injury, as well as to promote graft function and maintain adequate gas exchange. Hypotension and varying degrees of pulmonary edema are common in the immediate postoperative lung transplantation setting. Ventricular dysfunction in lung transplant recipients should also be considered. Therefore, adequate volume and hemodynamic management with vasoactive agents based on their physiological effects and patient response are critical in the early postoperative lung transplantation period. Integrated management provided by a professional multidisciplinary team is essential for the critical care management of lung transplant recipients in the ICU.

• 한국분말재료학회지
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• 제5권4호
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• pp.250-257
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• 1998

The synthesis of titanium silicides ($Ti_3Si$, $TiSi_2$, $Ti_5Si_4$, $Ti_5Si_3$ and TiSi) by mechanical alloying has been investigated. Rapid, self-propagating high-temperature synthesis (SHS) reactions were observed to produce the last three phases during room-temperature high-energy ball milling of elemental powders. Such reactions appeared to be ignited by mechanical impact in an intimate, fine powder mixture formed after a critical milling period. During the high-energy ball milling, the repeated impact at contact points leads to a local concentration of energy which may ignite a self-propagating reaction. From in-situ thermal analysis, each critical milling period for the formation of $Ti_5Si_4$, $Ti_5Si_3$ and TiSi was observed to be 22, 35.5 and 53.5 min, respectively. $Ti_3Si$ and $TiSi_2$, however, have not been produced even till the milling period of 360 min due to lack of the homogeneity of the powder mixtures. The formation of titanium silicides by mechanical alloying and the relevant reaction rates appeared to depend upon the critical milling period, the homogeneity of the powder mixtures, and the heat of formation of the products involved.

• 한국분말재료학회지
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• 제6권2호
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• pp.145-151
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• 1999

Nickel silicides ($Ni_5$Si$_2$, Ni$_2$Si and NiSi) have been synthesized by mechanical alloying (MA) of Ni-27.9at.9at%Si, Ni-33.3at% and Ni-50.0at% powder mixtures, respectively. From in situ thermal analysis, eash citical milling period for the formation of the three phases was observed to be 40.2, 34.9 and 57.5 min, at which there was a rapid increase in temperature. This indicates that rapid, self-propagating high-temperature synthesis (SHS) reactions were observed to produce the three phases during room-temperature high-energy ball milling of elemental powders. Each Ni silicide, Ni and Si, however, coexisted for an extended milling time even after the critical milling period. The powders mechanically alloyed after the critical period showed the rapid increase in microhardness. The Hv values were found to be higher than 1000kgf/mm$^2$. The formation of nickel silicides by mechanical alloying and the relevant reaction rates appeared to be influenced by the critical milling period and the heat of formation of the products involved ($Ni_5$Si$_2$$\rightarrow$-43.1kJ/mol.at., Ni$_2$Si$\rightarrow$-47.6kJ/mol.at., NiSi$\rightarrow$-42.4kJ/mol.at).

• Animal cells and systems
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• 제5권4호
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• pp.327-331
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• 2001

There is a critical developmental period during which brain sexual differentiation proceeds irreversibly under the influence of gonadal hormone. Recently, kinesin superfamily-associated protein 3 (KAP3) gene expressed during the 'critical period' of rat brain differentiation was identified by us (Choi and Lee, 1999). KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons (Yamazaki et al., 1996). mRNA level of KAP3 gene markedly increased before the initiation of puberty. Neonatal treatment of estrogen clearly inhibited the prepubertal increase in KAP3 mRNA level (Choi and Lee, 1999). In the present study, we aimed to investigate the effects of polychlorinated biphenyls (PCBs), as endocrine disruptors (EDs) on the expression of KAP3 gene during the 'critical period' of rat brain development. In our data, PCBs significantly decreased the expression of KAP3 gene in the fetal (day 17) and the neonatal (day 6 after birth in) male and female rat brains. The body weight and the breeding ability were significantly decreased in the PCBs-exposed rats compared with the control. These results showed that PCBs affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the fetal and the neonatal rat brains. The maternal exposure to the PCBs may lead to toxic response in embryonic brain sexual differentiation and breeding ability after sexual maturation. This study indicates that KAP3 gene may be useful as a gene marker to analyze the molecular mechanism of toxic response in the animal brain development and sexual maturation exposed to PCBs.

• 한국식품영양학회지
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• 제22권3호
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• pp.377-386
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• 2009

The principal objective of this study was to evaluate the influence of temperature and salt concentration on the physicochemical properties of salted Chinese cabbage. Salted Chinese cabbage samples were prepared with various concentrations of salt(4, 5, 6 and 7%), and were stored for 10 days at three temperatures(8, 14, and $25^{\circ}C$). The salting ratio of Chinese cabbage evidenced a decreasing trend regardless of the salting temperature and salt concentration, and their decrement appeared relatively high as the salting temperature increased. The period required to achieve a critical salting ratio(85%) decreased with increases in the salt concentration at $25^{\circ}C$, and a similar trend was observed at lower temperatures(8 and $14^{\circ}C$). The salinity of all samples evidenced an increasing trend during the salting period, and at $25^{\circ}C$, in particular, a continuous increment was observed. At salt concentrations of 4%, the critical salinity(2.2%) was not achieved regardless of the temperature and salting period. The pH of salted Chinese cabbage achieved critical pH in 3 days at a salting temperature of $25^{\circ}C$, but the critical pH 5.5 of samples at 8 and $14^{\circ}C$ appeared after a long period of approximately 4 to 10 days. The average hardness values of salted Chinese cabbage at a salting ratio of 85% were approximately 1.49 MPa, 1.87 MPa, and 1.97 MPa, respectively, at three temperatures($25^{\circ}C$, $14^{\circ}C$, and $8^{\circ}C$). The initial reducing sugar content of cabbage juice was 11.8 mg/$m{\ell}$, and this value decreased substantially to 3 to 5 mg/$m{\ell}$ on day 1.

• 성인간호학회지
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• 제18권1호
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• pp.31-40
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• 2006

Purpose: The descriptive-correlational study was undertaken in order to investigate the relationships between critical thinking disposition and critical thinking skill in clinical nurses. Methods: A convenience sample of 50 registered nurses was obtained from E University Hospital. The instruments used in this study were general characteristics, California Critical Thinking Disposition Inventory (CCTDI) and California Critical Thinking Skill Test(CCTST) developed by Facione & Facione (1994). The data were analyzed by descriptive statistics, t-test, ANOVA, Duncan test and Pearson's Correlation Coefficient with SPSS 12.0 Program. Results: 1) There was a statistically significant difference in critical thinking disposition according to age (F=3.23, p=.03) and educational background (F=39.07, p=.00). 2) There was a statistically significant difference in critical thinking skill according to age (F=3.40, p=.02), educational background(F=32.51, p=.00), and period of professional nursing experience(F=3.56, p=.02). Conclusion: A significant positive correlation between critical thinking disposition and critical thinking skill was found(r=.68, p=.00). Critical thinking disposition and critical thinking skill according to age and educational background had statistically significant differences. Therefore, it is needed to emphasize the necessity of continuous education and training of nurses which prepare their critical thinking ability.

• 대한족부족관절학회지
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• 제17권1호
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• pp.52-59
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• 2013

Purpose: The purpose of this study is to evaluate treatment results of multidisciplinary approach of critical ischemic limb with diabetic foot. Materials and Methods: From March 2005 to March 2012, 674 diabetic foot patients were analyzed. Among them, 85 patients were neuroarthropathic type, 383 patients were infectious type, and 206 patients were ischemic type. The subjects were 206 patients who had critical ischemic limbs and major or minor amputations were done. Various single or combined treatment method before amputation was performed. We investigated their ABI, HbA1c, main occlusion lesion, limb salvage and hospitalization period by various treatment method. Results: Major amputation was 27 cases, minor amputation was 179 cases. Mean HbA1c was 8.2%, and mean ABI was 0.66. Main occlusion lesion was 6 cases at common iliac artery, 13 cases at external iliac artery, 9 cases at internal iliac artery, 11 cases at common femoral artery, 23 cases at deep femoral artery, 52 cases at superficial femoral artery, 35 cases at popliteal artery, 40 cases at posterior tibia artery, 35 cases at anterior tibial artery, 28 cases at peroneal artery, and 13 cases at dorsalis pedis artery. Major amputations were decreased, minor amputations were increased, and hospitalization period was reduced by treatment of multidisciplinary approach. Conclusion: Treatment of multidisciplinary approach, which include preoperation percutaneus transluminal angioplasty, vascular surgery, and amputation, of critical ischemic limb with diabetic foot had advantages of limb salvage and hospitalization period reduction.

• 한국안전학회지
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• 제9권3호
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• pp.74-81
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• 1994

The critical spontaneous ignition temperature for activated carbon were observed by performing experiments for granulated activated carbon with varying the period. As the results of the experiments, the critical spontaneous ignition temperature according to period of 0.5hr, 1.5hr and 2.5hr was 177.5$^{\circ}C$, 176.5$^{\circ}C$ and 172.5$^{\circ}C$ respectively, and the approximate expression of the critical spontaneous ignition temperature obtained for ambient temperature amplitudes was as follow ; $\delta$$_{c}$ (X, $\omega$)=$\delta$$_{c}${1-0.381 exp(-0.930.$\omega$$^{0.811}$)}.

• Tuberculosis and Respiratory Diseases
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• 제86권1호
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• pp.65-66
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• 2023