• 수산해양기술연구
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• 제19권1호
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• pp.57-62
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• 1983

접지전지 설계를 위한 Zn, Al 및 Mg의 합급양극의 특성을 실험적으로 조사한 결과를 다음과 같이 요약할 수 있다. 1. 환경비저항 1000 $\Omega$.cm 이하에서는 Zn합금양극이, 1000 $\Omega$.cm 이상에서는 Mg합금양극이 접지전지 설계에 좋다. 2. 비저항 500 $\Omega$.cm 이하에서는 Al합금양극이 Mg 합금양극보다 접지전지 설계를 위한 유전양극 특성이 좋으나 모든 비저항에서 Zn합금양극보다 특성이 떨어진다. 3. 배유전유밀도가 급격히 증가하는 일정인가전압은 다음과 같다. \circled1 E 하(Zn)=log (4.9465/$\rho$상(0.0639))+11$\times$10 상(-6)$\rho$상(0.8923i) \circled2 E 하(Al)=log (4.9306/$\rho$상(0.0525))+13$\times$10 상(-6)$\rho$상(0.9314i) \circled3 E 하(Mg)= log (3.7086/$\rho$상(0.0988))+181$\times$10 상(-6)$\rho$상(0.5406i) 4. 유전양극의 종류 및 환경의 비저항에 따라 인가전압과 배유전유밀도의 관계는 다음과 같은 일반식으로 표시할 수 있다. logi=g+root(n.E+r)

• 한국주조공학회지
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• 제27권2호
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• pp.83-87
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• 2007

Aluminum plates of the same materials as the foam were attached by the casting process inserting the foam as a core to investigate the tensile property of open cell foams. Tensile properties of the open cell 6063 aluminum alloy foam of $10{\sim}30$ PPI were measured before and after heat treatment. Densities of test specimens were between 0.14 and $0.29g/cm^3$. Tensile strength of the 6063 aluminum foam after heat treatment showed little change. C values were in the range of $0.41{\sim}0.87$ for as cast foams and $0.11{\sim}0.27$ for T6 heat treated foams in the eq. of ${\sigma}^* _{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_s)^{1.5}$, and increased with increase in the cell size.

• 한국주조공학회지
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• 제27권1호
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• pp.36-41
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• 2007

Compressive properties of the open cell 6063 aluminum alloy foams made by the plaster molding process were investigated before and after heat treatment. Loading process was controlled at a displacement rate of 2 mm/min. Compressive strength of 10 PPI foam was the largest of the same density foams. Increase in strength after heat treatment for the bulk material was remark able, however was not for the 6063 aluminum foam. C values were in the range of $0.39{\sim}0.53$ for as cast foams and $0.13{\sim}0.16$ for T6 heat treated foams in the equation of ${sigma}^*_{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_{s})^{1.5}$ and increased with cell size.

• BMB Reports
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• 제51권6호
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• pp.296-301
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• 2018

Mitochondrial DNA (mtDNA) mutations are often observed in various cancer types. Although the correlation between mitochondrial dysfunction and cancer malignancy has been demonstrated by several studies, further research is required to elucidate the molecular mechanisms underlying accelerated tumor development and progression due to mitochondrial mutations. We generated an mtDNA-depleted cell line, ${\rho}^0$, via long-term ethidium bromide treatment to define the molecular mechanisms of tumor malignancy induced by mitochondrial dysfunction. Mitochondrial dysfunction in ${\rho}^0$ cells reduced drug-induced cell death and decreased the expression of pro-apoptotic proteins including p53. The p53 expression was reduced by activation of nuclear $factor-{\kappa}B$ that depended on elevated levels of free calcium in $HCT116/{\rho}^0$ cells. Overall, these data provide a novel mechanism for tumor development and drug resistance due to mitochondrial dysfunction.

• 한국수산과학회지
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• 제41권4호
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• pp.301-304
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• 2008

For bioremediation of the benthic layer uptake kinetics of phosphate by microphytobenthos Nitzschia sp.(JFH200406) were investigated. A short-term phosphate uptake revealed that the maximum uptake rate(${\rho}_{max}$) and half-saturation constant($K_s$) were 0.132 pmol/cell/hr and 502.6 ${\mu}M$, respectively. The maximum specific uptake rate calculated between ${\rho}_{max}$ and the phosphorus cell quota($Q_p$), calculated from Strathmann equation, was 14.4/day. The values of these parameters indicate that Nitzschia sp. accommodates well to surroundings of high phosphate, and can uptake over 14-times more than the phosphorus cell quota. Thus, microphytobenthos Nitzschia sp. may be a useful species for bioremediation of the benthic layer.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.73-81
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• 1999

Shake mixing has been widely used in cell culture. The mixing performance for shake mixing, however, has not been reported quantitatively. The critical circulating frequency and the power consumption for complete suspension of particles, based on the definition of Zwietering, were measured in a shaking vessel containing a solid-liquid system. The critical suspension frequency was correlated by the equation from Baldi's particle suspension model modified with the physical properties of the particles. Critical suspension frequency was correlated as following ; $$N_{JS}={\frac{0.58\;d{_p}^{0.06}(g{\Delta}{\rho}/{\rho}_L)^{0.004}X^{0.03}}{D^{0.35}d^{0.17}{\upsilon}^{0.04}}}$$ The power consumption at the critical suspension condition in the shaking vessel was less than that in an agitated vessel with impeller.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.195-196
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• 2008

결정질 실리콘 웨이퍼의 도핑농도와 도핑깊이, 비저항은 태양전지의 효율을 결정하는데 매우 중요한 요소이다. 높은 효율을 갖는 태양전지의 설계를 위해 PC1D를 이용해 태양전지의 에미터 도핑농도와 깊이, 베이스 비저항을 조절하였다. 최적화 결과 emitter peak doping $1\times10^{19}cm^{-3}$와 depth factor $1{\mu}m$, base $\rho$ $ 0.1\Omega$-cm, 즉 sheet resistance $69.15\Omega$/square와 $X_j$ $1.603{\mu}m$일 때 $I_{sc}$ = 5.478(A), $V_{oc}$ = 0.7013(V), $P_{max}$ = 2.828(W), FF = 73.61(%), Efficiency = 19.03(%)의 고효율을 얻을 수 있다.

• Journal of Gastric Cancer
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• 제20권4호
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• pp.408-420
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• 2020

Purpose: Isoform 2 of tight junction protein claudin-18 (CLDN18.2) is a potential target for gastric cancer treatment. A treatment targeting CLDN18.2 has shown promising results in gastric cancer. We investigated the clinical significance of CLDN18.2 and other cell-adherens junction molecules (Rho GTPase-activating protein [RhoGAP] and E-cadherin) in metastatic diffuse-type gastric cancer (mDGC). Materials and Methods: We evaluated CLDN18.2, RhoGAP, and E-cadherin expression using two-plex immunofluorescence and quantitative data analysis of H-scores of 77 consecutive mDGC patients who received first-line platinum-based chemotherapy between March 2015 and February 2017. Results: CLDN18.2 and E-cadherin expression was significantly lower in patients with peritoneal metastasis (PM) than those without PM at the time of diagnosis (P=0.010 and 0.013, respectively), whereas it was significantly higher in patients who never developed PM from diagnosis to death than in those who did (P=0.001 and 0.003, respectively). Meanwhile, CLDN18.2 and E-cadherin expression levels were significantly higher in patients with bone metastasis than in those without bone metastasis (P=0.010 and 0.001, respectively). Moreover, we identified a positive correlation between the expression of CLDN18.2 and E-cadherin (P<0.001), RhoGAP and CLDN18.2 (P=0.004), and RhoGAP and E-cadherin (P=0.001). Conversely, CLDN18.2, RhoGAP, and E-cadherin expression was not associated with chemotherapy response and survival. Conclusions: CLDN18.2 expression was reduced in patients with PM but significantly intact in those with bone metastasis. Furthermore, CLDN18.2 expression was positively correlated with other adherens junction molecules, which is clinically associated with mDGC and PM pathogenesis.

• 한국수정란이식학회지
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• 제25권2호
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• pp.103-110
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• 2010

The first morphogenetic event of preimplantation development, compaction, was required efficient production of porcine embryos in vitro. Compaction of the porcine embryo, which takes place at post 4-cell stage, is dependent upon the adhesion molecule E-cadherin. The E-cadherin through ${\beta}$-catenin contributes to stable cell-cell adhesion. Rho-associated kinase (ROCK) signaling was found to support the integrity of E-cadherin based cell contacts. In this study, we traced the effects of ROCK-1 on early embryonic development and structural integrity of blastocysts in pigs. Then, in order to gain new insights into the process of compaction, we also examined whether ROCK-1 signaling is involved in the regulation of the compaction mediated by E-cadherin of cellular adhesion molecules. As a result, real-time RT-PCR analysis showed that the expression of ROCK-1 mRNA was presented throughout porcine preimplantation stages, but not expressed as consistent levels. Thus, we investigated the blastocyst formation of porcine embryos treated with LPA and Y27632. Blastocysts formation and their qualities in LPA treated group increased significantly compared to those in the Y27632-treated group (p < 0.05). Then, to determine whether ROCK-1 associates embryonic compaction, we explored the effect of activator and/or inhibitor of ROCK-1 on compaction of embryos in pigs. The rate of compacted morula in LPA treated group was increased compared to that in the Y27632-treated group (39.7 vs 12.0%). Furthermore, we investigated the localization and expression pattern of E-cadherin at 4-cell stage porcine embryos in both LPA- and Y27632-treated groups by immunocytochemical analysis and Western blot analysis. The expression of E-cadherin was increased in LPA-treated group compared to that in the Y27632-treated group. The localization of E-cadherin in LPA-treated group was enriched in part of blastomere contacts compared to that Y27632-treated group. ROCK-1 as a crucial mediator of embryo compaction may plays an important role in regulating compaction through E-cadherin of the cell adhesion during the porcine preimplantation embryo. We concluded that ROCK-1 gene may affect the developmental potential of porcine blastocysts through regulating embryonic compaction.

• Nutrition Research and Practice
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• 제11권4호
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• pp.275-280
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• 2017

BACKGROUND/OBJECTIVES: Re-epithelialization has an important role in skin wound healing. Astaxanthin (ASX), a carotenoid found in crustaceans including shrimp, crab, and salmon, has been widely used for skin protection. Therefore, we investigated the effects of ASX on proliferation and migration of human skin keratinocyte cells and explored the mechanism associated with that migration. MATERIAL/METHOD: HaCaT keratinocyte cells were exposed to $0.25-1{\mu}g/mL$ of ASX. Proliferation of keratinocytes was analyzed by using MTT assays and flow cytometry. Keratinocyte migration was determined by using a scratch wound-healing assay. A mechanism for regulation of migration was explored via immunocytochemistry and western blot analysis. RESULTS: Our results suggest that ASX produces no significant toxicity in human keratinocyte cells. Cell-cycle analysis on ASX-treated keratinocytes demonstrated a significant increase in keratinocyte cell proliferation at the S phase. In addition, ASX increased keratinocyte motility across the wound space in a time-dependent manner. The mechanism by which ASX increased keratinocyte migration was associated with induction of filopodia and formation of lamellipodia, as well as with increased Cdc42 and Rac1 activation and decreased RhoA activation. CONCLUSIONS: ASX stimulates the migration of keratinocytes through Cdc42, Rac1 activation and RhoA inhibition. ASX has a positive role in the re-epithelialization of wounds. Our results may encourage further in vivo and clinical study into the development of ASX as a potential agent for wound repair.