• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.1-5
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• 2019

We investigated the effect of Fe₃O₄ addition on the critical temperature of (Bi, Pb)-2223 polycrystalline samples. Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_10+δ + x wt. % Fe₃O₄ (x = 0.0, 0.2, 0.4, 0.6, and 0.8) samples were prepared by using a solid-state reaction method. The analysis of X-ray diffraction data indicates that as Fe₃O₄ is added, dominant phase of the sample changes from Bi-2223 to Bi-2212 with an increasing Bi-2201 phase. The transition temperature of the samples drastically decreased with the Fe₃O₄ addition. The resistance data of samples with x = 0.2 and 0.4 showed a double transition indicating a coexistence of Bi-2223 and Bi-2212 phase while the samples with x = 0.6 and 0.8 showed a single transition with a semiconducting behavior. This phase transition may originate from changes in local structure of the Bi-2223 system by Fe₃O₄ addition. Analysis of the pair distribution function of the Cu-O pair in the CuO₂ plane calculated from extended X-ray absorption fine structure data revealed that the oxygen coordination of copper ion changes from CuO₄ planar type (x = 0.0 - 0.4) to CuO₅ pyramidal type (x = 0.6, 0.8). The correlated Debye-Waller factor, providing information on the atomic disorder within the CuO₂ plane, shows an inverse relation to the coordination number. These results indicate that addition of Fe₃O₄ changes the oxygen distribution around Cu in the CuO₂ plane, causing a phase transition from Bi-2223 to more stable Bi-2212/Bi-2201 phases.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.737-748
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• 1997

Distribution of rhEGF in the skin, plasma and several organ tissues following topical application of $^{125}I-rhEGF$ (0.4${\mu}$Ci) solution in 25% Pluronic F-127 on 154$mm^2$ normal and damaged (burned and stripped) skins of hairless mice was examined. The radioactivity in the stripped skin tissues increased as a function of time, and was 10-20 times higher than that in the normal and burned skins. The fractions of intact drug in the skin tissues were 40-60% for the normal and burned skins, and 60-80% for the stripped skin. It indicates that the stratum corneum layer behaves as a barrier for the dermal penetration of the drug. The radioactivity in the plasma was much higher for the stripped skin than for the normal and burned skins. However, the concentration of intact drug in the stripped skin was comparable to those in the normal and burned skins indicating most severe degradation (or metabolism) of the drug in the stripped skin. As a result, the fraction of intact drug in the plasma was lowest for the stripped skin (<10%). Body organ distribution of the drug was much higher for the stripped skin. The concentration in the stomach. Both in total radioactivity and intact drug, showed more than 10-times higher value than in the other organs (liver, kidney and spleen). The fraction of intact drug in each organ tissue was below 10-20%. And generally lowest for the stripped skin. The lowest fraction of the drug for the stripped skin could not be explained by the activity of the aminopeptidases in the skin since it was lower for the stripped skin than for the normal skin. Thereover, the fraction of intact drug appears to be determined by the balance between dermal uptake and systemic elimination of the drug, for example. The mechanism of dermal uptake of rhEGF was examined by topical applying 200${\mu}$l of 25% Pluronic F-127 solution containing 0.4 ${\mu}$Ci of $^{125}I-rhEGF$ and 0.14${\mu}$Ci of $^{14}C$-inulin (a marker of passive diffusion). The radioactivity of $^{125}I-rhEGF$ at each sampling time point (0.5, 1, 2, 4 and 8hr) was correlated (p<0.05) with the corresponding radioactivity of $^{14}C$-inulin. It appears to indicate the rhEGF may be uptaken into the skins mainly by the passive diffusion. This hypothesis was supported by the constant specific binding of EGF to the skin homogenates regardless of the skin models. Receptor mediated endocytosis (RME) appears to contribute negligibly, if any, to the overall uptake process.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.257-267
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• 2020

The goal of suction denture is to enhance retention of dentures by the formation of negative pressure between the denture base and the underlying tissue and sealing around the denture by the mucosa. This patient has been converted to a completely edentulous state after the extraction of residual teeth. Fabrication of suction denture was planned because it was estimated that the conventional compete would be hard to achieve retention due to the absorption of residual ridge and lack of sublingual fold. Through appropriate clinical and laboratory technique such as preliminary impression on the mandibular rest position, provisional vertical dimension determination with Centric Tray^® (Ivoclar Vivadent AG, Schaan, Liechtenstein), closed mouth definitive impression and jaw relation record using individual tray with Gnathometer M^® (Ivoclar Vivadent AG, Schaan, Liechtenstein), artificial teeth arrangement considering stability of the denture, and proper polymerization technique that minimizes polymerization shrinkage, restoring the patient with suction denture resulted in satisfaction throughout the function and asesthetics.

• Korean Journal of Materials Research
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• v.8 no.8
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• pp.737-743
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• 1998

The synthesis of $SrAI_2O_4:Eu^{2+}$ phosphor and its properties of both photoluminescence and long-phosphorescent were investigated as a function of sintering condition. Single phase of $SrAl_2O_4$ was obtained by sintering the mixtures of $SrCO_3$, $Eu_2O_3$, $AI_2O_34 and 3wt% $B_2O_3$ powders over 100$0^{\circ}C$ in Ar/H2 atmosphere. The optimum sintering condition for the long-phosphorescent phosphor of $SrAI_2O_4:Eu^{2+}$ was found at 130$0^{\circ}C$ for 3hours. The PL emission spectrum of $SrAI_2O_4:Eu^{2+}$ shows a maximum peak intensity at 520nm(2.384eV) with a broad emission extending from 450 to 650nm which resulted from the $4f^65d^1$$\rightarrow$$4f^7$ transition of $Eu^{+2}$ under 360nm exitation. Monitored at 520nm. the excita¬tion spectrum of $SrAI_2O_4:Eu^{2+}$ exhibits a maximum peak intensity at 360nm (3.44eV) with a broad absorption band extending from 250 to 480nm.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.118-125
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• 2002

Hydration is the main reason for the growth of the material properties. An exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development of all material properties and the formation of microstructure should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of W/C ratio on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The tatter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration. In this study, the effects of chemical composition of cement, W/C ratio, temperature, and moisture conditions on the degree of hydration are considered. Parameters that can be used to indicate or approximate the real degree of hydration are liberated heat of hydration, amount of chemically bound water, and chemical shrinkage, etc. Thus, the degree of heat liberation and adiabatic temperature rise could be determined by prediction of degree of hydration.

• Journal of Nutrition and Health
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• v.38 no.10
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• pp.817-826
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• 2005

Recently it has been reported that vitamin A and retinol binding proteins (RBPs) in blood and urine were changed in the condition of diabetes mellitus or hyperlipidemia. Fruits and vegetables are recommended to consume for the people suffered from these chronic degenerative diseases. The main components of fruits and vegetables are dietary fibers, for example cellulose and pectin, of which function to affect the absorption and excretion of dietary fat and fat-soluble substances. This study was conducted to investigate the effect of dietary fibers on RBPs mRNA expression in liver, small intestine and serum of rat fed high fat diet during 4 weeks. Sprague-Dawley rats, weighing 121g on average, were divided into four groups; (Control; $17\%$ fat & cellulose supplement diet, HF0: $25\%$ fat & fiber free diet, B:.Uc: $25\%$ fat & cellulose supplement diet and HF0: $25\%$ fat & pectin supplement diet) . The rats fed high fat diet groups (HF0, HFC, HFP) tended to consume the food less than the control group, but FER of HF0 groups was significantly higher than the control (p < 0.05) . The weight of adrenal gland in high fat diet groups (HF0, HFC, HFP) was significantly less than the control. Total lipid in feces daily excreted and in liver did not show any significant differences among the groups. Total cholesterol in HFP group was significantly different from that of HFC group. Serum total cholesterol and triglyceride in other group tended to lower than other groups and HDL cholesterol higher. Consequently, AI (atherogenic index) was the lowest in HFP group. Vit A contents in feces daily excreted tended to lower in high fat diet groups (HF0, HFP) compared to the control group. That content in adrenal gland was the lowest in HF0 group, but not in liver. In HFP group were down-regulated cRBPI mRNA in liver and cRBPII mRNA in small intestine and up-regulated RBP and transthyretin expression in serum compared to the other groups. In conclusion, dietary fibers, especially pectin, in high fat diet might down-regulate the expression of CRBP I, CRBP II mRNA in liver and small intestine, but increase the secretion of RBP into serum and therefore inhance the bioavailability of Vit A through the body. (Korean J Nutrition 38(10): 817$\sim$826,2005)

• KIPS Transactions on Software and Data Engineering
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• v.12 no.3
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• pp.125-132
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• 2023

In this study, we compared the performance of machine learning models for predicting Vapor Pressure Deficits (VPD) in greenhouses that affect pore function and photosynthesis as well as plant growth due to nutrient absorption of plants. For VPD prediction, the correlation between the environmental elements in and outside the greenhouse and the temporal elements of the time series data was confirmed, and how the highly correlated elements affect VPD was confirmed. Before analyzing the performance of the prediction model, the amount and interval of analysis time series data (1 day, 3 days, 7 days) and interval (20 minutes, 1 hour) were checked to adjust the amount and interval of data. Finally, four machine learning prediction models (XGB Regressor, LGBM Regressor, Random Forest Regressor, etc.) were applied to compare the prediction performance by model. As a result of the prediction of the model, when data of 1 day at 20 minute intervals were used, the highest prediction performance was 0.008 for MAE and 0.011 for RMSE in LGBM. In addition, it was confirmed that the factor that most influences VPD prediction after 20 minutes was VPD (VPD_y__71) from the past 20 minutes rather than environmental factors. Using the results of this study, it is possible to increase crop productivity through VPD prediction, condensation of greenhouses, and prevention of disease occurrence. In the future, it can be used not only in predicting environmental data of greenhouses, but also in various fields such as production prediction and smart farm control models.

• Journal of the Korean neurological association
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• v.35 no.1
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• pp.8-15
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• 2017

Near-infrared spectroscopy (NIRS), a noninvasive optical method, utilizes the characteristic absorption spectra of hemoglobin in the near-infrared range to provide information on cerebral hemodynamic changes in various clinical situations. NIRS monitoring have been used mainly to detect reduced perfusion of the brain during orthostatic stress for three common forms of orthostatic intolerance (OI); orthostatic hypotension, neurally mediated syncope, and postural orthostatic tachycardia syndrome. Autonomic function testing is an important diagnostic test to assess their autonomic nervous systems for patients with symptom of OI. However, these techniques cannot measure dynamic changes in cerebral blood flow. There are many experimentations about study of NIRS to reveal the pathophysiology of patients with OI. Research using NIRS in other neurologic diseases (stroke, epilepsy and migraine) are ongoing. NIRS have been experimentally used in all stages of stroke and may complement the established diagnostic and monitoring tools. NIRS also provide pathophysiological approach during rehabilitation and secondary prevention of stroke. The hemodynamic response to seizure has long been a topic for discussion in association with the neuronal damage resulting from convulsion. One critical issue when unpredictable events are to be detected is how continuous NIRS data are analyzed. Besides, NIRS studies targeting pathophysiological aspects of migraine may contribute to a deeper understanding of mechanisms relating to aura of migraine. NIRS monitoring may play an important role to trend regional hemodynamic distribution of flow in real time and also highlights the pathophysiology and management of not only patients with OI symptoms but also those with various neurologic diseases.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.2
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• pp.153-161
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• 2024

Vitamin D is a fat-soluble vitamin that is mainly produced in the skin by UV rays. Along with melatonin, it is a representative chronobiotic substance, and the skin plays an important role in distinguishing between day and night. However, vitamin D cannot be used directly in cosmetics because it is a vitamin that acts as a coenzyme and plays a hormonal role in regulating the expression of various types of genes. Therefore, it was to investigate the skin efficacy of provitamin D (7-dehydrocholesterol), a vitamin D precursor that can be used in cosmetics. Our findings reveal that pro vitamin D can effectively inhibit the expression of tyrosinase, the melanin-producing enzyme, thereby attenuating melanin synthesis. This skin tone regulatory effect has been corroborated in vitro using artificial skin models. Additionally, pro vitamin D demonstrated anti-inflammatory properties by suppressing the expression of TNFa and, upon conversion to vitamin D through UV exposure, it was observed to induce the production of the antimicrobial peptide CAMP (LL-37). The inhibitory effect of pro vitamin D on melanin production appears to be a result of it reducing the UV absorption capacity of melanin, thereby inducing the conversion of pro D to vitamin D. Utilizing pro vitamin D in cosmetic formulations could not only modulate skin tone and enhance skin immunity but also expect to contribute to other cutaneous benefits as anti-aging and barrier function improvement with everyday UV exposure. This multifaceted efficacy positions pro vitamin D as a promising ingredient in advancing the formulation of skin care products.

• Journal of the Mineralogical Society of Korea
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• v.17 no.3
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• pp.209-220
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• 2004

Adsorption behavior of Cu onto Hwangto, from Pankok-ri, Kosung-gun, suspension was studied using Cu batch adsorftion experiment and computer program MINTEQA2 and FITEQL 3.2. The sorption of copper was investigated as a function of pH, copper concentration and $NaNO_3$ background concentration (0.01 and 0.1 M). The concentration of copper was analyzed using ICP-AES. The sorption of copper onto Hwangto suspension increased with increasing pH and copper concentration. The adsorption percentage of copper drastically increased from pH 5.5 to 6.5, and reached nearly 100% at pH 7.5. Because the amount of copper solution and the ionic strength of background electrolyte may not affect the sorption of copper onto Hwangto, the copper ion may be combined at the surface of Hwangto as an inner-sphere complex. Using the MINTEQA2 program, the speciation of copper was calculated as a function of pH and copper concentration. The concentration of $Cu^{2+}$ decreased and that of $Cu(OH)_2$ increased with increasing pH. The uptake of copper in the Hwangto suspension was simulated by FITEQL3.2 program using two sites-three pKas model, which is composed of silicate reaction site and Fe oxide reaction site. The copper absorption reaction constants were calculated in the case of 2～6 mL of copper solution. The Fe oxide reaction site rapidly adsorbs copper ion between pH 4.5～6.5. Silicate reaction site adsorbs little copper ion at low copper concentration but much at high copper concentration. The removal amount of copper by precipitation was negligible in comparison with that of adsorption. The Fe oxide reaction site may has higher adsorption affinity of copper ion than silicate reaction site.