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Hydrothermal Reaction for the Preparation of La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3
Sang M. Lee,Hungsu Im,Bon-Heun Koo,Chan-Gyu Lee,Gom-Bai Chon 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6
Fine powders of perovskite structured manganites, La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3, were synthesized by using a hydrothermal reaction, followed by a calcination reaction in some cases. X-ray diffraction (XRD) patterns showed the desired composition without other impurity phases after calcination. Scanning electron microscopy (SEM) showed clean and pure images. The magnetic property measurement was performed in a vibrating sample magnetometer (VSM). The ferromagnetic-paramagnetic transition temperature of La0.7Ca0.3MnO3 was around 240 K and of La0.7Sr0.3MnO3 was around 350 K.hiK
S-715 Giant Cell Arteritis with Cerebral Artery Involvement Proven by Brain Biopsy
( Sang Hoon Park ),( Ho Hyun Park ),( Seung Hun Kang ),( Bon San Koo ) 대한내과학회 2016 대한내과학회 추계학술대회 Vol.2016 No.1
Introduction:?Giant cell arteritis (GCA) is categorized as a vasculitis of large and medium sized vessels. Cerebral artery involvement with pathological findings is not well documented in GCA patients. We report a rare case of GCA with cerebral vessels involvement in a 76-year-old woman.?Case:?A 76-year-old female patient was referred to the Department of Neurosurgery due to drowsy mentality. Brain magnetic resonance imaging demonstrated an expanding mass in the left frontal lobe. The patient underwent a left frontal craniotomy. Histological analysis of the specimen revealed extensive infarction with foci of organization. The tissue adjacent to the necrosis exhibited frequent multinucleated giant cells. Multinucleated giant cells were also observed in the meningeal and intracortical vessel walls. The tissue also exhibited wall necrosis and perivascular lymphocytic infiltration. Meningeal arteries frequently demonstrate intimal thickening with luminal narrowing. A few well-formed granulomas were observed, which were predominantly located in the meningeal tissue. However, there was no evidence of neoplasm and tuberculosis. These findings suggested that the patient was suffering from vasculitis of the cerebral vessels. She was referred to the Department of Rheumatology. To find further vascular involvement, computed tomography (CT) angiography was performed, which indicated stenosis and occlusion of the left temporal artery. In addition, diffuse narrowing and stenosis with slightly decreased distal flow on the M1 segment of the left middle cerebral artery (MCA) were observed. According to the 1990 American College of Rheumatology GCA classification criteria, she met at least 3 parameters: age, decreased pulsation of the temporal artery, and abnormal artery biopsy results. She was treated with high dose methylprednisolone. After steroid therapy, her mental status was recovered. After 3 months, regression of the MCA stenosis was detected in follow-up CT angiography.?Conclusions:?We report a rare case of GCA patient with cerebral artery involvement. This case showed that GCA may present as the involvement of cerebral artery and was proven by brain biopsy.
Sung-Hun Min,Joo-Hee Hong,Humdai Park,Deog-Bon Koo 한국동물생명공학회(구 한국동물번식학회) 2011 발생공학 국제심포지엄 및 학술대회 Vol.2011 No.1
Freezing of bovine blastocysts has been proposed as a tool to improve the feasibility of cattle production by using embryo transfer technique. However, the low efficiency of frozen-thawed embryos survival and further development is a crucial problem. Thus, we examined the effect of artificial shrinkage before vitrification of bovine expanded, hatched and SCNT embryos on the survival rate, apoptosis index and further development after thawing. Expanded, hatched and SCNT embryos were vitrified after artificial shrinkage, which was performed by puncturing the blastocoele with a pulled pasteur pipet. Artificial shrinkage of the blastocyst was achieved after pushing a pulled pasteur pipet into the blastocoele cavity until it contracted. The shrunken and not shrunken embryos were exposed to cryoprotectant solution in 7.5% ethylene glycol-7.5% DMSOPBS with 20% FBS for 5 min. They were placed in a small volume of vitrification solution (15% ethylene glycol+15% DMSO+PBS+20% FBS+0.5 M sucrose) and plunged into liquid nitrogen on a cryotop. Then, after thawing, cryoprotectant was diluted in 1.0 M, 0.5 M, 0.25 M, and 0 M sucrose for 1, 3, 5, and 5 min. Under the optimal conditions, overall efficiency of the survival rate of bovine expanded, hatched, SCNT embryos in artificial shrinkage groups was higher compared with non-artificial shrinkage groups (p< 0.05). Especially, the numbers of TUNEL-positive nuclei in artificial shrinkage groups were significantly reduced than those of non-artificial shrinkage groups among frozen-thawed expanded, hatched, and SCNT blastocysts (p< 0.05). Our results showed that survival rates in cryopreserved expanded, hatched, SCNT embryos could be improved by reducing the fluid content. Therefore, we suggest that artificial shrinkage method is a effective pretreatment technique for the cryotop vitrification of expanded, hatched, SCNT bovine blastocysts.
Sung Jae Kim,M. S. Anwar,Eun Ji Kim,Hyeon Ji Cho,송태권,Bon Heun Koo,Hang Joo Ko 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.1
Highly transparent Zn/SnO2/Zn conducting multilayer films are prepared on quartz glass substrates by using RF sputtering. The deposited films were annealed at various temperatures for thermal diffusion. The influences of annealing temperature, annealing time and the zinc thickness on the structural, electrical and optical properties of the multilayer films were studied. X-ray diffraction results showed that all p-type conducting films possessed polycrystalline SnO2 with a tetragonal rutile structure. Hall measurements indicates that annealing at 450 C for 2 h was the optimum annealing parameters for p-type Zn (5 nm)/SnO2 (300 nm)/Zn (5 nm) multilayer films with a hole concentration and resistivity of 9.80 × 1016 cm−3 and 352 ·cm, respectively. The average transmission of the p-type Zn/SnO2/Zn multilayer films was above 87% in the visible range.
( Bon San Koo ),( Hye-jin Jeong ),( Chang-nam Son ),( Sang-hyon Kim ),( Hyun Jung Kim ),( Gheun-ho Kim ),( Jae-bum Jun ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.0
Background/Aims: We investigated the distribution of serum uric acid (SUA) levels and estimated the prevalence of hyperuricemia and hypouricemia in the Korean population. Methods: This cross-sectional study used data from the Korean Genome and Epidemiology Study and included 172,970 participants (58,981 men and 113,989 women) aged 40 to 79 years. Hypouricemia and hyperuricemia were defined as SUA level ≤ 2.0 mg/dL and > 7 mg/dL, respectively. The prevalence of hyperuricemia and hypouricemia was evaluated by age and sex. Results: The mean SUA levels were significantly higher in men than in women (5.71 ± 1.27 mg/dL vs. 4.21 ± 0.96 mg/dL, p < 0.001). The mean SUA levels and prevalence of hyperuricemia increased with age in women but not in men. The overall prevalence of hyperuricemia and that in men and women was 50.82, 133.25, and 8.17 per 1,000 persons, respectively; the overall prevalence of hypouricemia and that in men and women was 4.16, 1.10, and 5.75 per 1,000 persons, respectively. The prevalence of hypouricemia in men was similar across all age groups; however, that in women was the highest in the age group of 40 to 49 years and the lowest in the age group of 50 to 59 years. Conclusions: The distribution of SUA levels and prevalence of hyperuricemia and hypouricemia differed according to age and sex. Age and sex should be considered in studies on uric acid-related diseases.