• Journal of the Korean Magnetics Society
• /
• v.15 no.6
• /
• pp.315-319
• /
• 2005

To obtain low switching field ($H_{SW}$) we introduced amorphous ferromagnetic $Co_{70.5}Fe_{4,5}Si_{15}B_{10}$ single and synthetic antiferromagnet (SAF) free layers in magnetic tunnel junctions (MTJs). The switching characteristics for MTJs with structures $Si/SiO_2/Ta$ 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) were investigated and compared to MTJs with $Co_{75}Fe_{25}$ and $Ni_{80}Fe_{20}$ free layers. CoFeSiB showed a lower saturation magnetization of $560 emu/cm^3$ and a higher anisotropy constant of $2800\;erg/cm^3$ than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the CoFeSiB single and SAF free layer MTJs, it was frond that the size dependence of the $H_{SW}$ originated from the lower $J_{ex}$ experimentally and by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. The CoFeSiB SAF structures showed lower $H_{SW}$ than that of NiFe, CoFe and CoFeSiB single structures. The CoFeSiB SAF structures were proved to be beneficial far the switching characteristics such as reducing the coercivity and increasing the sensitivity in micrometer to submicrometer-sized elements.

• Journal of Life Science
• /
• v.25 no.4
• /
• pp.433-440
• /
• 2015

Several studies suggest that regular consumption of walnuts may have beneficial effects against oxidative stress-mediated disease such as cancer. The present study reports the total phenolic and flavonoid contents, together with the antioxidant and antibacterial activities of several solvent extracts (methanol, n-hexane, ethyl acetate, n-butanol, and water) obtained from walnut (Juglans regia L.) green husk. MIC (minimal inhibitory concentration) values of the walnut extracts for 8 human pathogenic bacteria strain were determined using agar dilution method. Antioxidant activity of extracts were assessed using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) assays, EC₅₀ of DPPH and ABTS scavenging activities, and determination of total phenolic and flavonoid content and its correlation with DPPH and ABTS scavenging capacities. Among the six extracts, ethyl acetate extract (EtOAc Ex) showed the highest antimicrobial activity at 3.2 mg/ml of MICs against Staphylococcus aureus SG511. Total flavonoids and polyphenol contents of EtOAc Ex were 42.48 mg of quercetin equivalents (QE)/g and 223.25 mg of gallic acid equivalents (GAE)/g respectively. The highest antioxidative potential was shown by the sample extracted with EtOAc Ex (EC₅₀=13.43 μg/ml for DPPH and EC₅₀=41.83 μg/ml for ABTS radical scavenging activity assay). These results showed that J. regia green husk extracts can be used as an easily accessible source of natural antibacterial agents and natural antioxidants.

• Journal of Life Science
• /
• v.20 no.5
• /
• pp.710-716
• /
• 2010

This study was conducted to investigate the effect of Makgeolli (MG) and Makgeolli GiGemi (MGG) on blood flow, serum lipid improvement in vivo, and inhibition of angiotensin converting enzyme (ACE) in vitro. The activities of serum AST and ALT were increased by ovariectomy. Serum AST levels were decreased to $77.71{\pm}13.97$ and $74.57{\pm}14.90\;unit/ml$ in the OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($91.14{\pm}12.02\;unit/ml$). Serum ALT levels were decreased to $34.00{\pm}8.41$ and $30.43{\pm}3.60\;unit/ml$ in OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($37.14{\pm}5.40\;unit/ml$). Serum total cholesterol and triglyceride contents decreased in the sham group compared with OVX-control group by ovariectomy. Six weeks feeding of MG and MGG resulted in a decrease to $116.14{\pm}36.02$ and $109.14{\pm}11.55\;mg/dl$ compared to the OVX-control group ($120.43{\pm}8.36\;mg/dl$) in serum total cholesterol, and triglyceride levels were decreased to $52.43{\pm}12.41$ and $47.29{\pm}12.08\;mg/dl$ in the OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($58.57{\pm}5.47\;mg/dl$). The level of HDL-cholesterol in the OVX-control group was significantly reduced to $51.29{\pm}20.49\;mg/dl$ compared to the sham group ($72.29{\pm}10.29\;mg/dl$), but it was increased to $70.71{\pm}19.53$ and $62.00{\pm}20.20\;mg/dl$ with MG and MGG supplementation. Furthermore, the effect of the MG group was higher than the MGG group. Microscopic observation showed that whole blood passed smoothly through the micro channels in the MG and MGG supplemented groups. The platelet aggregation ability of the groups treated with MG and MGG was less than that of the OVX-control group. In vitro assay, the angiotensin converting enzyme (ACE) activity was significantly inhibited by MG and MGG (82.6% and 68.9% inhibition at 0.4 g/ml). These results suggest that the beneficial effects of MG and MGG may be used to improve on the lipid metabolic syndrome of menopausal women. In addition, MG and MGG might improve blood homeostasis mediated activities via antiplatelets and MG and MGG may be used as antihypertensive functional foods and nutraceuticals.

• Tuberculosis and Respiratory Diseases
• /
• v.70 no.4
• /
• pp.293-300
• /
• 2011

Chronic obstructive pulmonary disease (COPD) is a substantially under-diagnosed disorder, and the diagnosis is usually delayed until the disease is advanced. However, the benefit of early diagnosis is not yet clear, and there are no guidelines in Korea for doing early diagnosis. This review highlights several issues regarding early diagnosis of COPD. On the basis of several lines of evidence, early diagnosis seems quite necessary and beneficial to patients. Early diagnosis can be approached by several methods, but it should be confirmed by quality-controlled spirometry. Compared with its potential benefit, the adverse effects of spirometry or pharmacotherapy appear relatively small. Although it is difficult to evaluate the benefit of early diagnosis by well-designed trials, several lines of evidence suggest that we should try to diagnose and manage patients with COPD at early stages of the disease.

• KDI Journal of Economic Policy
• /
• v.12 no.2
• /
• pp.81-94
• /
• 1990

Illegal transactions such as blackmarketing and smuggling allegedly result from too restrictive trade policies. A recent U.S. Senate hearing on the blackmarketing of American goods imported into Korea for the purpose of supporting United States troops and their dependents stationed in Korea concluded with the allegation that Korea's highly restrictive trade practices are responsible for the emergence of the black market. It has also suggested that the removal of such restrictive trade policies would eliminate black market activities. This study addresses the relationship between trade policy and blackmarketing by investigating whether trade liberalization results in the reduction of illegal transactions, and whether the eradication of blackmarketing indeed improves social welfare. When both legally imported goods and illegally exchanged items command the same price, trade liberalization, meaning a decrease in tariff rates or an increase in import quotas, will increase the quantity of legal imports at the expense of illegally transacted goods on the black market. But the price of legally imported goods usually differs from that of illegally sold ones. In this case, a change in the relative prices of these two groups of goods due to a change in trade policy will give rise to income, as well as substitution, effects. Initially, a decrease in the import price due to a decrease in import tax rates or an increase in the allotted quota will reduce illegal transactions, since the decrease in the import price will induce the substitution of legal imports for illegally exchanged, but otherwise, identical goods. On the other hand, the demand for the illegally transacted goods will rise, because of the income effect of the reduced import price. Thus, assuming the positive income effect overwhelms the negative substitution effect, the demand for illegal goods will increase, thwarting the reduction of blackmarketing through trade liberalization. Yet, stepping up the enforcement measures which are geared to preventing blackmarketing itself will drastically reduce the extent of illegal transactions, since it increases the cost of blackmarketing and hence the price of the illegally transacted goods. What this study suggests is that the emergence of the black market in Korea should be attributed more to the excessive supply of duty-free goods imported through U.S. commissaries and exchanges than to the excessive demand for foreign goods. On the other hand, blackmarketing, in most cases, improves economic welfare, since it constitutes an increase in the "actual" amount of imported goods. Suppressing blackmarketing through stepped-up enforcement methods is beneficial only when the substitution effect of the legally transacted goods resulting from the increase in the price of the illegal goods prevails, since the increase in the demand for legal imports must override the decrease in the demand for black market goods as well as the negative income effect.

• Journal of Navigation and Port Research
• /
• v.26 no.3
• /
• pp.323-328
• /
• 2002

Soil-steel structures have been used for the underpass, or drainage systems in the road embankment. This type of structures sustain external load using the correlations with the steel wall and engineered backfill materials. Buried flexible conduits made of corrugated steel plates for the coastal road was tested under vehicle loading to investigate the effects of live load. Testing conduits was a circular structure with a diameter of 6.25m. Live-load tests were conducted on two sections, one of which an attempt was made to reinforce the soil cover with the two layers of geo-gird. Hoop fiber strains of corrugated plate, normal earth pressures exerted outside the structure, and deformations of structure were instrumented during the tests. This paper describes the measured static and dynamic load responses of structure. Wall thrust by vehicle loads increased mainly at the crown and shoulder part of the conduit. However additional bending moment by vehicle loads was neglectable. The effectiveness of geogrid-reinforced soil cover on reducing hoop thrust is also discussed based on the measurements in two sections of the structure. The maximum thrusts at the section with geogrid-reinforced soil cover was 85-92% of those with un-reinforced soil cover in the static load tests of the circular structure; this confirms the beneficial effect of soil cover reinforcement on reducing the hoop thrust. However, it was revealed that the two layers of geogrid had no effect on reducing the overburden pressure at the crown level of structure. The obtained values of DLA decrease approximately in proportion to the increase in soil cover from 0.9m to 1.5m. These values are about 1.2-1.4 times higher than those specified in CHBDC.

• Journal of Chest Surgery
• /
• v.31 no.4
• /
• pp.353-361
• /
• 1998

Hypothermia is widely acknowledged as fundamental component of myocardial protection during cardiac operations. Although it prolongs the period of ischemic arrest by reducing oxygen demands, hypothermia is associated with a number of major disadvantages, including its detrimental effects on enzymatic function, energy generation, and cellular integrity. The ideal way to rotect the heart is to electromechanically arrest it and perfus it with blood that is aerobic arrest. However alternative technique has been developed, based on the principles of electromechanical arrest and normothermic aerobic perfusion using continuous warm blood cardioplegia. To determine if continuous warm blood cardioplegia was beneficial in clinical practice during valvular surgery, we studied two groups of patients matched by numbers and clinical characteristics. Group included is 31 patients undergoing valvular surgery who received intermittent cold crystalloid cardioplegia. Group II included 30 patients undergoing valvular surgery who received continuous warm blood cardioplegia. Our results suggest that the heartbeat in 100% of patients treated with continuous warm blood cardioplegia converted to normal sinus rhythm spontaneously after the removal of the aortic cross-clamp, compared to only 31% of the cold cardioplegia group. After operation, pericardial closure rate was 90% area in the warm group, compared to 35% area in the cold group. 12 hours after the operation, the total amount of urine output in the warm group was greater than that in the cold group(2863${\pm}$127 ml versus 2257${\pm}$127 ml; p<0.05). After the operation, left diaphragmatic elevation developed in 55% of the cold group but in 0% of the warm group. CK-MB level in the warm group was significantly lower than cold group(2.28${\pm}$0.62 versus 9.96${\pm}$2.12; p<0.01) 1 hour after operation and CK-MB level in the warm group was significantly lower than cold group(1.80${\pm}$1.01 versus 6.00${\pm}$1.74; p<0.05) 12hours after operation. Continuous warm blood cardioplegia is at least as safe and effective as hypothermic technique in patients undergoing cardiac valvular surgery. Conceptually, this represents a new approach to the problem of maintaining myocardial preservation during cardiac operations.

• Journal of Chest Surgery
• /
• v.32 no.3
• /
• pp.249-254
• /
• 1999

Background: Recovery of the left atrial contractile function after the Cox-Maze procedure is related to the size of the left atrium. We have postulated that if too wide area of the atrium were isolated electrically, then the atrial contractile function would be impaired postoperatively. We have modified the Cox-Maze procedure to dissect each pair of the pulmonary veins separately instead of the conventional pulmonary vein encircling incision, and compared the atrial contractile function after each procedure. Material and Method: From February 1995 to October 1997, 55 cases of the Cox-Maze procedure were performed in mitral valvular heart disease. We excluded the cases that did not covert to sinus rhythm. The patient groups were divided according to the interpulmonary vein distance(IPVD) and the procedure performed. Group I was IPVD under 6.5 cm(n=30), group II was IPVD over 6.5cm and the conventional Cox-Maze III procedure was performed(n=16), and group III was IPVD over 6.5cm and the modified Cox-Maze procedure was performed(n=9). Result: Atrial contractile function was evaluated by the echocardiography follow-up between 6 months to 12 months. The right atrial contractile function recovered gradually, the recovery rate after long-term follow-up was 90% in group I, 81% in group II, and 100% in group III(p>0/05). In the left atrium the recovery rate was 63% in group I, 31% in group II(p=0.03), and 66% in group III(p>0.05). Conclusion: The modified Cox-Maze procedure may have beneficial effects on the recovery of the left atrial contractile function, however, there are no statistically significant values. Therefore, further evaluation of this procedure is necessary.

• Radiation Oncology Journal
• /
• v.24 no.1
• /
• pp.51-57
• /
• 2006

Puroose: We examined whether intratumoral (i.t.) administration of dendritic cells (DCs) into a treated tumor could induce local and systemic antitumor effects in a mouse tumor model. Methods and Materials: C57BL/6 mice were inoculated s.c. in the right and left thighs with MCA-102 fibrosarcoma cells on day 0 and on day 7, respectively. On day 7, the tumors (usually 6 mm in diameter) on the right thigh were heated by immersing the tumor-bearing leg in a circulating water bath at $43^{\circ}C$ for 30 min; thereafter, the immature DCs were i.t administered to the right thigh tumors. This immunization procedure was repeated on days 7, 14 and 21. The tumors in both the right and left thighs were measured every 7 days and the average sizes were determined by applying the following formula, tumor $size=0.5{\times}(length+width)$. Cytotoxicity assay was done to determine tumor-specific cytotoxic T-lymphocyte activity. Results: Hyperthermia induced apoptosis and heat shock proteins (HSPs) in tumor occurred maximally after 6 hr. For the local treated tumor, hyperthermia (HT) alone inhibited tumor growth compared with the untreated tumors (p<0.05), and furthermore, the i.t. administered DCs combined with hyperthermia (HT + DCs) additively inhibited tumor growth compared with HT alone (p<0.05). On the distant untreated tumor, HT alone significantly inhibited tumor growth (p<0.05), and also HT + DCs potently inhibited tumor growth (p<0.001); however, compared with HT alone, the difference was not statistically significant. In addition, HT + DCs induced strong cytotoxicity of the splenocytes against tumor cells compared to DCs or HT alone. Conclusion: HT + DCs induced apoptosis and increased the expression of HSPs, and so this induced a potent local and systemic antitumor response in tumor-bearing mice. This regimen may be beneficial for the treatment of human cancers.

• Childhood Kidney Diseases
• /
• v.17 no.2
• /
• pp.92-100
• /
• 2013

Purpose: To investigate the clinicopathologic effects of cyclosporine A (CsA) in children with diseases characterized by mesangial immunoglobulin A deposits such as immunoglobulin A nephropathy (IgAN) and Henoch-Sch$\ddot{o}$nlein purpura nephritis (HSPN). Methods: We retrospectively reviewed the clinicopathologic outcomes of 54 children (IgAN, 36; HSPN, 18) treated with CsA. The starting dose of CsA was 5 mg/kg per day, and it was administered in 2 divided doses. The degree of proteinuria and pathologic changes in renal biopsies were evaluated before and after CsA treatment. Results: The mean protein to creatinine ratio decreased from $3.7{\pm}1.5$ to $0.6{\pm}0.4$(P <0.001), and 32 (59.2%) children achieved complete remission of proteinuria after 1-year CsA treatment. Among the 54 children, 24 maintained normal renal function and 25 exhibited microscopic hematuria or proteinuria at the end of CsA treatment. In the HSPN group, 3 children whose initial biopsies indicated class IIIb disease showed class II disease on follow-up, and the follow-up biopsies of 2 children who had class II disease indicated the same class II disease. In the IgAN group, cortical tubular atrophy occurred in 1 child, and no child with IgAN had cortical interstitial fibrosis or tubular atrophy after 1-year CsA treatment. No significant complications were found in the children treated with CsA. Conclusion: Our findings indicate that CsA treatment is effective and beneficial in reducing massive proteinuria and preventing progression to end-stage renal failure in children with glomerular diseases characterized by IgA deposits, such as IgAN and HSPN, within 1 year of treatment.