• Korean Journal of Microbiology
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• v.42 no.2
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• pp.111-115
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• 2006

A feeding trial was conducted to test the use of marine yeasts isolated from seawaters and sediments as a dietary source in cultivating a Cladocera, Moina macrocopa which is available as an alternative live food for fish larvae. The marine yeast-fed M. macrocopa had similar essential amino acid profiles to the documented values for Rotifers and Artemia enriched in microalgae and commercial diets. Erythrobacter sp. $S{\pi}-1$ lacked ${\omega}-3$ high unsaturated fatty acids (HUFAs), $20:5{\omega}-3$ (EPA) and $22:6{\omega}-3$ (DHA), which were also poor but detected in both the marine yeasts. An increase in the $20:5{\omega}-3$ and $22:6{\omega}-3$ levels, compared with the levels in marine yeast strains themselves, was more pronounced in the $22:6{\omega}-3$ level of Moina fed the Candida sp. Y-16, resulting in a high DHA:EPA ratio. When the Moina diets were switched, their ${\delta}^{13}C$ values shifted gradually toward the values of the switched diets. Diet switch from Erythrobacter sp. $S{\pi}-1$to Candide sp. Y.16 resulted in a more rapid turnover of Moina tissue carbon than that in the inverse case. When fed a mixed diet, the ${\delta}^{13}C$ values of Moina tissue approached the value of marine yeasts immediately. These temporal changes in the ${\delta}^{13}C$ values of Moina tissue indicate the preferential ingestion of marine yeasts and a selective assimilation of the carbon originated from marine yeasts. These findings suggest that marine yeasts, particularly Candida sp. Y-16, are highly available to mass cultures of M. macrocopa, providing better nutritional and dietaty values than the commercial diet (Erythrobacter sp. $S{\pi}-1$).

• Korean Journal of Materials Research
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• v.13 no.3
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• pp.200-204
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• 2003

A statistical experiment method was employed to investigate the window of the thermal stability of $TiSi_2$films which are popular for Ti-salicide and ohmic layers. The statistical experimental results showed that the first order term of $TiSi_2$thickness and annealing temperature was acceptable as a function of $\Delta$resistivity by 95% reliability criteria, and R-sq value implying a fit accuracy of the model also showed a high value of 93.80%. We found that $\Delta$resistivity of the $TiSi_2$film annealed at $700^{\circ}C$ for 1 hr changed from 3.35 to $0.379\mu$$\Omega$$\cdot$cm with increasing thickness from 185 to $703\AA$, and TEX>$\Delta$resistivity of the $TiSi_2$film with a fixed thickness of 444 $\AA$ changed from 0.074 to 17.12 $\mu$$\Omega$$\cdot$cm with increasing temperature increase from 600 to $800^{\circ}C$. From these results, we report that the process conditions of$ 692^{\circ}C$-1 hr, $715^{\circ}C$-1 hr, and 73$0^{\circ}C$-1 hr for $TiSi_2$($400 \AA$) are stable by the criteria of 1, 2, and 3 $\mu$$\Omega$$\cdot$cm of $\Delta$resistivity, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.238-238
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• 2012

Ag (silver)의 일함수는 T-OLED (Top Emission Organic Light Emitting Diode)의 전극소자로 사용하기에는 다소 낮다는 단점이 있다(~4.3 eV). 이러한 단점을 해결하기 위한 대안으로 Ag 박막의 표면을 플라즈마 처리, UV 처리 및 열처리를 통하여 일함수를 높이는 연구가 진행 되어왔다(>5.0 eV). 하지만 현재의 대부분 연구는 후 처리된 박막의 일함수에 초점을 맞춰 연구가 진행 되어 박막의 nano-mechanical property에 대한 연구는 매우 부족하다. 따라서 본 논문에서는 AgOx 박막의 nano-mechanical property에 초점을 맞춰 분석을 실시하였다. 연구에 사용된 샘플은 Ag 박막을 유리기판 위에 rf-magnetron sputter 장치를 이용하여 100 W의 power로 150 nm 두께로 증착하였다. 증착된 Ag 박막은 $O_3$ 발생 UV 램프를 이용하여, 다양한 시간동안 UV 처리하였다(0~9분). 증착된 샘플은 Four-point probe, nanoindenter 장비를 이용하여 nano-mechanical property를 분석하였다. 실험 결과 UV 처리 시간이 0, 1분에서 면저항이 0.16, 0.50 ${\Omega}$/sq로 급격한 변화가 나타났으나, 반면 3분 이후 9분의 샘플의 경우, 0.55 ${\Omega}$/sq에서 0.24, 0.20, 0.15 ${\Omega}$/sq로 감소하여 전기적 특성변화를 볼 수 있었다. 또한 nanoindenting 결과 UV 처리한 박막의 극 표면 경도 값의 변화는 0~5분 처리한 샘플의 경우, 물리적인 경도가 증가하는 형태를 보이며 UV 처리를 5분간 했을때 7.89 GPa로 최고의 경도를 가진다. 그 이후부터는 6.97, 3.46 GPa의 결과로 박막의 경도가 감소되는 결과를 얻었다. 이러한 결과로부터 Ag 박막의 후처리에 따른 Ag 물질의 산화 및 결정상태에 따라 박막 내에 존재하는 residual stress를 분석할 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.39.2-39.2
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• 2010

In this work we have investigated electrical and optical properties of interface for ITO/Si with shallow doped emitter. The ITO is prepared by DC magnetron sputter on p-type monocrystalline silicon substrate. As an experimental result, The transmittance at 640nm spectra is obtained an average transmittance over 85% in the visible range of the optical spectrum. The energy bandgap of ITO at oxygen flow from 0% to 4% obtained between 3.57eV and 3.68eV (ITO : 3.75eV). The energy bandgap of ITO is depending on the thickness, sturcture and doping concentration. Because the bandgap and position of absorption edge for degenerated semiconductor oxide are determined by two competing mechanism; i) bandgap narrowing due to electron-electron and electron-impurity effects on the valance and conduction bands (> 3.38eV), ii) bandgap widening by the Burstein-Moss effect, a blocking of the lowest states of the conduction band by excess electrons( < 4.15eV). The resistivity of ITO layer obtained about $6{\times}10^{-4}{\Omega}cm$ at 4% of oxygen flow. In case of decrease resistivity of ITO, the carrier concentration and carrier mobility of ITO film will be increased. The contact resistance of ITO/Si with shallow doped emitter was measured by the transmission line method(TLM). As an experimental result, the contact resistance was obtained $0.0705{\Omega}cm^2$ at 2% oxygen flow. It is formed ohmic-contact of interface ITO/Si substrate. The emitter series resistance of ITO/Si with shallow doped emitter was obtained $0.1821{\Omega}cm^2$. Therefore, As an PC1D simulation result, the fill factor of EWT solar cell obtained above 80%. The details will be presented in conference.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.222-231
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• 2019

Among fatty acid families, the polyunsaturated fatty acids were demonstrated to be mediators in various reproductive processes as precursor of steroid hormone (via cholesterol) and prostaglandins (via arachidonic acid), and in the last decade, major research was focused on the effects of omega-6 and especially omega-3 fatty acid. Eicosapentaenoic acid, the longest members of omega-3 fatty acid family, can be produced by a series of desaturation and elongation reactions from shorter member such as α-Linolenic acid. However, very few studies have provided detailed descriptions of Eicosapentaenoic acid effects and mechanisms of action in mammalian oocytes. The purpose of this study was to evaluate the effect of Eicosapentaenoic acid supplementation on in vitro maturation and developmental potential of porcine oocytes. Various concentrations of Eicosapentaenoic acid was added into in vitro maturation medium, and we evaluated the degree of cumulus expansion, nuclear maturation rate, blastocysts quality, and levels of prostaglandin E2, 17β-estradiol, progesterone in the spent medium. High doses (100 μM) of Eicosapentaenoic acid supplementation significantly inhibited cumulus expansion and oocyte nuclear maturation, and prostaglandin E2 synthesis also significantly decreased compared with other groups (p < 0.05). Supplementation of 50 μM Eicosapentaenoic acid showed higher quality blastocysts in terms of high cell numbers and low apoptosis when compared with other groups (p < 0.05), and synthesis ratio of E2/P4 also significantly increased compared with control group (p < 0.05). However, Supplementation of 100 μM Eicosapentaenoic acid showed high apoptosis when compared with other groups (p < 0.05), and synthesis ratio of 17β-estradiol/progesterone also significantly decreased compared with control group (p < 0.05). Our results indicated that supplementation with appropriate levels of Eicosapentaenoic acid beneficially affects the change of hormone synthesis for controlling oocyte maturation, leading to improved embryo quality. However, high doses of Eicosapentaenoic acid treatment results in detrimental effects.

• Clinical and Experimental Reproductive Medicine
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• v.47 no.3
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• pp.168-179
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• 2020

Objective: This study investigated testicular oxidative stress status and physiomorphological function in Wistar rats fed with yaji and cadmium chloride (CdCl₂). Methods: Sixty male albino Wistar rats (12 per group) were randomly assigned to five groups: group I (control), group II (300 mg/kg.bw of yaji), group III (500 mg/kg.bw of yaji), group IV (2.5 mg/kg.bw of CdCl₂), and group V (2.5 mg/kg.bw of yaji+4 mg/kg.bw omega-3). Each group was evenly subdivided into two subgroups and treatment was administered for 14 days and 42 days, respectively. Semen quality (sperm count, progressive motility, normal morphology, and gonadosomatic index), hormones (testosterone, follicle-stimulating hormone, and luteinizing hormone), testicular oxidative stress markers (superoxide dismutase, catalase, glutathione peroxidase, and malonaldehyde) and testicular histomorphological features were examined. Results: Yaji caused significant (p< 0.05) dose- and duration-dependent reductions in semen quality, the gonadosomatic index, testosterone, follicle-stimulating hormone, and luteinizing hormone. Yaji also caused significant (p< 0.05) dose- and duration-dependent decreases in superoxide dismutase, catalase, and glutathione peroxidase activity, as well as increased testicular malonaldehyde levels. Yaji induced distortions in the testicular histological architecture. CdCl₂ damaged testicular function by significantly (p< 0.05) reducing semen quality, reproductive hormone levels, and oxidative stress markers in albino Wistar rats. CdCl₂ also altered the histology of the testis. Conclusion: This study shows that yaji sauce has similar anti-fertility effects to those of CdCl₂, as it adversely interferes with male reproduction by impairing oxidative stress markers and the function and morphological features of the testis.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.729-734
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• 2002

Radiorespirometric analysis revealed that Pseudomonas sp. strain KKI isolated from a soil contaminated with petroleum hydrocarbons was able to catabolize polycyclic aromatic hydrocarbons such as phenanthrene and naphthalene. The rate and extent of phenanthrene mineralization was markedly enhanced when the cells were pregrown on either naphthalene or phenanthrene, compared to the cells grown on universal carbon sources (i.e., TSA medium). Deduced amino acid sequence of the Rieske-type iron-sulfur center of a putative phenanthrene dioxygenase (PhnAl) obtained from the strain KKI shared significant homology with DxnAl (dioxin dioxygenase) from Spingomonas sp. RW1, BphA1b (biphenyl dioxygenase) from Spingomonas aromaticivorans F199, and PhnAc (phenanthrene diokygenase) from Burkholderia sp. RP007 or Alcaligenes faecalis AFK2. Northern hybridization using the dioxygenase gene fragment cloned from KKI showed that the expression of the putative phn dioxygenase gene reached the highest level in cells grown in the minimal medium containing phenanthrene and $KNO_3$, and the expression of the phn gene was repressed in cells grown with glucose. In addition to the metabolic change, phospholipid ester-linked fatty acids (PLFA) analysis revealed that the total cellular fatty acid composition of KKI was significantly changed in response to phenanthrene. Fatty acids such as 14:0, 16:0 3OH, 17:0 cyclo, 18:1$\omega$7c, 19:0 cyclo increased in phenanthrene-exposed cells, while fatty acids such as 10:0 3OH, 12:0, 12:0 2OH, 12:0 3OH, 16:1$\omega$7c, 15:0 iso 2OH, 16:0, 18:1$\omega$6c, 18:0 decreased.

• Membrane Journal
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• v.6 no.4
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• pp.219-226
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• 1996

Rotary disc ultrafiltration module(RDM) was developed for the separation of oil emulsions. This module was devised to reduce the gel polarization phenomenon by alecoupling the operation pressure and the surface velocity of solution in ultrafiltration(UF) processes. Two-shaft engaged disc type RDM having 20 rotary disc membcanes(UOP, USA) was operated under 85kPa vacuum at $25^{\circ}$C. The pressure drop due to slip flow in the two-shaft RDM was found to be proportional to $(2.5{\omega}r)^{2}$. The pure water flux of two-shaft RDM decreased by 9.95% at the angular velocity of 41.89rad/s compared to the decrease of 3.01% for one-shaft RDM at the same velocity. When the angular velocity was changed from 31.42rad/s to 2.62rad/s, the flux decline for 1% cutting oil in two-shaft RDM was 30.16% that is similar to that of one-shaft RDM. Disc gap of 3mm and 7mm did not show any significant differences in the flux for 1% cutting oil solution. A modified model for two-shaft RDM showed good agreement with the experimental results for the cutting oil solution.

• Journal of Nutrition and Health
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• v.27 no.3
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• pp.215-227
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• 1994

Changes in total lipid content, total cholesterol content and fatty acid composition of preterm milk were investigated during early lactation. Milk samples were collected from Korean mothers of 16 premature(34 to 36 weeks gestation age) infants on day 2 to 5(colostrum) and at 6 weeks(mature) postpartum. We estimated the lipid nutrition of preterm milk by comparing with the lipids of term milk. The total lipid content of preterm colostrum was significantly lower than the lipid content of preterm mature milk(p<0.001). Lipid content, determined gravimetrically in colostrum and matured milk, was 1.50g/이 and 3.2g/dl, respectively. Also the total cholesterol content(mg/dl) in preterm milk tends to increase from 14.16mg/dl to 15.20mg/dl, while the total cholesterol(mg/g lipid) concentration higher significantly in colostrum(12.36mg/g) than in mature(5.73mg/g)(p<0.001). The total unsaturated fatty acid contents in preterm milk were higher in colostrum than in mature milk and the total saturated fatty acids were higher in mature milk. The average DHA contents of colostrum and matured milk was 0.64%, 0.53% and the P/M/S ratio of preterm milk were 0.63 : 1.05 : 1.00, 0.47 : 0.79 : 1.00, respectively. Also, $\omega$6/$\omega$3 ratio of preterm milk were 2.35 in colostrum and 5.81 in mature. Therefore, colostrum in preterm milk contained higher amounts of $\omega$3 PUFA than mature milk. The levels of total lipid in preterm milk were higher than term milk. Also, preterm milk is richer in cholesterol, and long chain polyunsaturated fatty acid than term. It appears that the milk secreted by mothers who delivered prematurely differs from milk in several important respect. These components may serve as precursors for membrane, myelin development in the preterm infants. Therefore, it would be necessary to study further into the machanism of how the gestation age might affect to the lipid composition in human milk. These data may provide a basis for better construction of infant formaulas to provide more adequately for the lipid requirements of the Korean premature infant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.93-97
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• 1987

The seeds cf Pinus Koraiensis mere studied for their moisture, total lipids and ash contents and fatty acid composition. The seeds contained ca. 3.6% moisture, 70.4% purified total lipids and 2.5% ash. The proximate composition of the seeds was not influenced by the sampling rears (1984 and 1985). Twenty-one fatty acids ranged from myristic to arachidic acids were identified in the seed lipids. The seed lipids contained linoleic acid (47.9%), oleic acid (28.4%) and 5, 9, 12-18:3(11.1%) as major fatty acids and 5,9,12-18:3, 5,11-20:2 and 5,11,14-20:3 as 5-olefinic nonmethylene-interrupted polyenoic acids. The sampling Tears also had no effect on the fatty acid composition of the seed lipids.