• 한국식품저장유통학회지
• /
• 제17권3호
• /
• pp.425-429
• /
• 2010

햄버거 패티에 L. monocytogenes cocktail을 인위적으로 접종한 후 UV-C 조사 처리에 따른 저장 중 미생물 수 변화를 조사하였다. 햄버거 패티에 접종된 L. monocytogenes의 초기 균수가 6-7 log CFU/mL가 되게 하였고, 사용된 UV-C 조사선량은 1, 5, 10 kJ/$m^2$이었으며 조사된 시료는 $4{\pm}1^{\circ}C$에서 7일 동안 저장하였다. UV-C 조사는 L. monocytogenes 수에 있어서 조사선량이 증가할수록 유의적으로(p<0.05) 감소하는 것을 나타냈다. 특히, 10 kJ/$m^2$ 처리구는 대조구와 비교하여 L. monocytogenes 수를 2.03 log CFU/g까지 감소시켰다. 햄버거 패티의 UV-C 처리에 의한 품질 변화 척도로써 측정한 TBARS 값은 저장 중 UV-C 처리 여부와 관계없이 증가하였다. 따라서 본 연구결과, UV-C 조사 처리는 햄버거 패티의 저장 중 품질 변화에 큰 영향을 주지 않으면서 미생물학적 안전성 확보에 효과적인 것으로 판단된다.

• 한국재료학회지
• /
• 제20권4호
• /
• pp.194-198
• /
• 2010

Cubic boron nitride (c-BN) is a promising material for use in many potential applications because of its outstanding physical properties such as high thermal stability, high abrasive wear resistance, and super hardness. Even though 316L austenitic stainless steel (STS) has poor wear resistance causing it to be toxic in the body due to wear and material chips, 316L STS has been used for implant biomaterials in orthopedics due to its good corrosion resistance and mechanical properties. Therefore, in the present study, c-BN films with a $B_4C$ layer were applied to a 316L STS specimen in order to improve its wear resistance. The deposition of the c-BN films was performed using an r.f. (13.56 MHz) magnetron sputtering system with a $B_4C$ target. The coating layers were characterized using XPS and SEM, and the mechanical properties were investigated using a nanoindenter. The friction coefficient of the c-BN coated 316L STS steel was obtained using a pin-on-disk according to the ASTM G163-99. The thickness of the obtained c-BN and $B_4C$ were about 220 nm and 630 nm, respectively. The high resolution XPS spectra analysis of B1s and N1s revealed that the c-BN film was mainly composed of $sp^3$ BN bonds. The hardness and elastic modulus of the c-BN measured by the nanoindenter were 46.8 GPa and 345.7 GPa, respectively. The friction coefficient of the c-BN coated 316L STS was decreased from 3.5 to 1.6. The wear property of the c-BN coated 316L STS was enhanced by a factor of two.

• Molecules and Cells
• /
• 제25권2호
• /
• pp.184-195
• /
• 2008

We examined the role of c-FLIP in the motility of HeLa cells. A small interfering RNA (siRNA) directed against c-FLIP inhibited the adhesion and motility of the cells without affecting their growth rate. The long form of c-FLIP ($c-FLIP_L$), but not the short form ($c-FLIP_S$), enhanced adhesion and motility. Downregulation of $c-FLIP_L$ with siRNA decreased phosphorylation of FAK and ERK, while overexpression of $c-FLIP_L$ increased their phosphorylation. Overexpression of FAK activated ERK, and enhanced the motility of HeLa cells. FRNK, an inhibitory fragment of FAK, inhibited ERK and decreased motility. Inhibition of ERK also significantly suppressed $c-FLIP_L$-promoted motility. Inhibition of ROCK by Y27632 suppressed the $c-FLIP_L$-promoted motility by reducing phosphorylation of FAK and ERK. Overexpression of $c-FLIP_L$ increased the expression and secretion of MMP-9, and inhibition of MMP-9 by Ilomastat reduced $c-FLIP_L$- promoted cell motility. A caspase-like domain (amino acids 222-376) was found to be necessary for the $c-FLIP_L$-promoted cell motility. We conclude that $c-FLIP_L$ promotes the motility of HeLa cells by activating FAK and ERK, and increasing MMP-9 expression.

• 대한전자공학회논문지
• /
• 제20권5호
• /
• pp.31-36
• /
• 1983

W.L.S. 알고리즘을 이용한 간접 M. R. L C. 방식으로서 직류전동기의 속도를 마이크로프로세서 M6509를 사용하여 제어하였으며 이를 통하여 W.L.S. 알고리즘의 빠른 수렴속도와 부하변동에 잘 적응하는 특성을 고략하였다.

• Parasites, Hosts and Diseases
• /
• 제45권2호
• /
• pp.103-109
• /
• 2007

Leishmania tropica and L. major are etiologic agents of human cutaneous leishmaniasis. Delayed type hypersensitivity (DTH) is an immunologic response that has been frequently used as a correlate for protection against or sensitization to leishmania antigen. In BALB/c mice, L. tropica infection results in non-ulcerating disease, whereas L. major infection results in destructive lesions. In order to clarify the immunologic mechanisms of these 2 different outcomes, we compared the ability of these 2 leishmania species in induction of DTH response in this murine model. BALB/c mice were infected with L. major or L. tropica, and disease evolution and DTH responses were determined. The results show that the primary L. major infection can exacerbate the secondary L. major infection and is associated with DTH response. Higher doses of the primary L. major infection result in more disease exacerbation of the secondary L. major infection as well as higher DTH response. L. tropica infection induces lower DTH responses than L. major. We have previously reported that the primary L. tropica infection induces partial protection against the secondary L. major infection in BALB/c mice. Induction of lower DTH response by L. tropica suggests that the protection induced against L. major by prior L. tropica infection may be due to suppression of DTH response.

• 한국식품과학회지
• /
• 제53권2호
• /
• pp.218-222
• /
• 2021

본 연구는 그람 음성균과 양성균인 E. coli와 L. monocytogenes를 인위적으로 오염시킨 음용수를 대상으로 UV-C 정수기의 살균 가능성과 미생물의 생육 저해에 따른 형태학적 특성을 조사하였다. UV-C를 이용한 음용수 살균 능력은 그람 음성균 E. coli와 양성균 L. monocytogenes의 저농도부터 고농도(E. coli 3.2×103-3.2×107 CFU/2.8 L; L. monocytogenes 8.4×103-8.4×107 CFU/2.8 L) 세균 모두의 생육을 저해할 수 있는 효과가 나타났다. 따라서 UV를 이용한 음용수 살균은 유속 3.4 L/min에서 UV-C 파장 254 nm, 조사선량 40 mJ/㎠로 조사할 경우 E. coli 3.2×107 CFU/2.8 L와 L. monocytogenes 8.4×107 CFU/2.8 L 이하 농도의 오염된 음용수의 살균이 가능한 것으로 나타났다. 정수기에 UV-C 살균장치를 추가하는 것이 물의 미생물 안전성에 효율적이라고 사료되며, 이 연구결과는 UV살균 장치 활용의 기초자료로 제공되어 향후 연구 수행에 도움을 줄 수 있을 것이다.

• 한국식품조리과학회지
• /
• 제11권4호
• /
• pp.379-385
• /
• 1995

저농도의 ethanol(3-7%, v/v)을 tryptic soy broth (TSB)에 첨가하여 L. monocytogenes의 증식과 생존에 미치는 효과를 이 세균의 최적온도(35$^{\circ}C$)와 저온(-20, 5$^{\circ}C$) 및 고온(45, 50, 55$^{\circ}C$)에서 검토하였다. 35$^{\circ}C$에서의 L. monocytogenes의 증식은 ethanol농도의 증가와 더불어 저해되었으며, 5% ethanol의 존재하에서는 긴 유도기를 거친 후에 증식이 시작되었으나 ethanol 7%에서는 생균수가 계속 감소하였다. 3-7%의 ethanol을 함유한 TSB에 $10^{5}$-$10^{6}$ cells/$m\ell$의 L. monocytogenes를 접종하여 저온(5$^{\circ}C$, -2$0^{\circ}C$)에 저장하였을 때 5$^{\circ}C$에서 세균은 5% 이하의 ethanol 첨가시에는 증식하였으나 -2$0^{\circ}C$에서는 저장초기에 생균수가 빠르게 감소한 후 감소속도는 느리게 진행되었다. 냉장과 동결저장에서 3%의 ethanol첨가로서 control의 90% 이상의 세균이 제거되었다. $10^{6}$-$10^{7}$ cells/$m\ell$의 L. monocytogenes를 접종하여 고온(45, 50, 55$^{\circ}C$)에 저장한 경우, L. monocytogenes의 생균수는 45$^{\circ}C$에서는 느리게 감소하였으며 3% 이하의 ethanol 첨가에 의한 항균효과는 뚜렷한 차이가 없었다. 5$0^{\circ}C$와 55$^{\circ}C$에서 생균수가 빠르게 감소하였는데 특히 55$^{\circ}C$에서는 3, 5, 7%의 ethanol첨가로서 세균의 사멸속도는 각각 control의 1.5배, 3배, 5배 정도 증가하였다.다.

• 대한수학회보
• /
• 제27권2호
• /
• pp.189-196
• /
• 1990

In this paper, we try to generalize ultraproducts in the category of locally convex spaces. To do so, we introduce D-ultracolimits. It is known [7] that the topology on a non-trivial ultraproduct in the category T $V^{ec}$ of topological vector spaces and continuous linear maps is trivial. To generalize the category Ba $n_{1}$ of Banach spaces and linear contractions, we introduce the category L $C_{1}$ of vector spaces endowed with families of semi-norms closed underfinite joints and linear contractions (see Definition 1.1) and its subcategory, L $C_{2}$ determined by Hausdorff objects of L $C_{1}$. It is shown that L $C_{1}$ contains the category LC of locally convex spaces and continuous linear maps as a coreflective subcategory and that L $C_{2}$ contains the category Nor $m_{1}$ of normed linear spaces and linear contractions as a coreflective subcategory. Thus L $C_{1}$ is a suitable category for the study of locally convex spaces. In L $C_{2}$, we introduce $l_{\infty}$(I. $E_{i}$ ) for a family ( $E_{i}$ )$_{i.mem.I}$ of objects in L $C_{2}$ and then for an ultrafilter u on I. we have a closed subspace $N_{u}$ . Using this, we construct ultraproducts in L $C_{2}$. Using the relationship between Nor $m_{1}$ and L $C_{2}$ and that between Nor $m_{1}$ and Ba $n_{1}$, we show thatour ultraproducts in Nor $m_{1}$ and Ba $n_{1}$ are exactly those in the literatures. For the terminology, we refer to [6] for the category theory and to [8] for ultraproducts in Ba $n_{1}$..

• Environmental Engineering Research
• /
• 제22권3호
• /
• pp.281-287
• /
• 2017

The joint effect of different concentrations (0.05-0.375 mmol/L) of $Cd^{2+}$ and various concentrations (50-400 mg/L) of [$C_3mim$][OAc] on the growth and physiology of wheat seedlings were investigated. The toxicity of $Cd^{2+}$ could be significantly reduced by lower concentrations (50-200 mg/L) of [$C_3mim$][OAc]. With higher concentration (${\geq}300mg/L$) of [$C_3mim$][OAc], the reduction became less, and compared to $Cd^{2+}$ stress only, the toxicity of 400 mg/L [$C_3mim$][OAc] increased. As for different $Cd^{2+}$ concentrations, the optimal reduction depends on the balance between the exact concentration of $Cd^{2+}$ and [$C_3mim$][OAc]: With low $Cd^{2+}$ concentration (0.05-0.250 mmol/L) requiring 50 mg/L [$C_3mim$][OAc], it could reach a dynamic equilibrium, while high $Cd^{2+}$ concentration (0.375 mmol/L) requiring 100 mg/L [$C_3mim$][OAc]. The growth and physiological indexes of wheat seedlings show a decrease in toxicity compared to the Cd alone treatment, when the dynamic equilibrium is reached. The concentration of $Cd^{2+}$ in leaf tissues showed that low concentration (50-200 mg/L) of [$C_3mim$][OAc] can reduce the toxicity of $Cd^{2+}$ (0.05-0.375 mmol/L) by decreasing the level of $Cd^{2+}$ concentration in the tissues, whereas the higher concentration (${\geq}300mg/L$) of [$C_3mim$][OAc] can increase the concentration of $Cd^{2+}$.

• 대한전자공학회논문지SD
• /
• 제44권9호
• /
• pp.59-70
• /
• 2007

본 논문에서는 휴대 정보기기 시스템에서 더욱 향상된 실시간 3D 그래픽 가속 능력을 갖는 SoC(System on a Chip) 구현을 위해 효과적인 T&L(Transform & Lighting) Processor 구조를 연구하였다. T&L 과정에 필요한 IP들을 설계하였으며, 이를 바탕으로 SoC Platform 기반으로 검증하였다. 설계된 T&L Processor는 24 bits 부동소수점 형식과 16 bits 고정소수점 형식을 적절하게 혼용하고 계산식의 병렬성을 최대한 활용하여 Transform 과정 연산과 Lighting 과정 연산의 지연시간을 균일하게 배분하여 Transform 과정만 처리할 때와 Lighting과 혼용으로 처리할 때 연산 속도의 차이가 없이 동작이 가능하다. 설계된 T&L Processor는 SoC 플랫폼을 이용하여 성능 측정 실험 및 검증을 하였고, Xilinx-Virtex4 FPGA에서 80 MHz의 동작 주파수를 확인하였고 초당 20M개의 정점(Vertex) 처리 성능을 확인하였다.