• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.17-17
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• 2016

Calcineurin governs stress survival, sexual differentiation, and virulence of the human fungal pathogen Cryptococcus neoformans. Herein, we identified and characterized calcineurin substrates in C. neoformans by employing phosphoproteomic $TiO_2$ enrichment and quantitative mass spectrometry. The identified targets include the zinc finger transcription factor Crz1 and proteins whose functions are linked to P-bodies/stress granules (PBs/SGs) and mRNA translation and decay, such as Pbp1 and Puf4. We show that Crz1 is a bona fide calcineurin substrate, and localization and transcriptional activity of Crz1 are controlled by calcineurin. Several of the calcineurin targets localized to PBs/SGs, including Puf4 and Pbp1, and are required for survival at high temperature and for virulence. Genetic epistasis analysis revealed that Crz1 and the novel targets Lhp1, Puf4, and Pbp1 function in a branched calcineurin pathway that orchestrates stress survival and virulence. These findings propose that calcineurin controls thermal stress and virulence at the transcriptional level via Crz1 and post-transcriptionally by regulating target factors involved in mRNA metabolism.

• Journal of the Korean Institute of Gas
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• v.12 no.4
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• pp.14-20
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• 2008

In this numerical study, the leakage safety of the LNG tank in which is constructed by membrane inner tank-plywood-polyurethane form-plywood-prestressed concrete structures has been presented for four leakage analysis models. The LNG leak criterion of the tank wall with a storage capacity of $200,000\;m^3$ is analyzed based on the thermal resistance technique. This means that if the cryogenic temperature of a leaked LNG is detected at the outer side of the PC wall, it may be leaked through the wall thickness of the tank. The calculated results based on the thermal resistance method between two walls show that the plywood, PUF, and another plywood walls may block the leakage of the leaked LNG even though the strength of these walls is already collapsed by a leaked LNG pressure. But, the leaked LNG may pass the thickness of the prestressed concrete wall for a period of elapsed time even though the PC outer tank supports the leaked LNG pressure. Thus, the PC outer tank may extend the leakage time of a leaked LNG.

• Journal of Life Science
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• v.16 no.4
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• pp.632-639
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• 2006

Here we examined the expression patterns and regulation of seven photosynthesis (PS) genes (puf, puc, puhA, bchC, bchE, bchF, and bchI) in the anoxygenic photosynthetic bacterium, Rhodobacter sphaeroides, based on lacZ reporter gene assay. Expression of the tested PS genes, except puhA and bchI, were strongly induced in R. sphaeroides grown under anaerobic conditions relative to that under aerobic conditions. The puhA and bchI genes appear to form the operons together with bchFNBHLM-RSP0290 and crtA, respectively. Expression of the puf, puc, and bchCXYZ operons in R. sphaeroides grown photosynthetically was proportional to the incident light intensity, whereas that of bchFNBHLM(RSP0290-puhA) was inversely related to light intensity. Expression of bchEJG was lowest under medium-light photosynthetic conditions $(10\;W/m^2)$ and highest under high light conditions $(100\;W/m^2)$. The regulation of PS genes by the three major regulatory systems involved in oxygen- and light-sensing in R. sphaeroides is as following: puf and bchC are regulated by both the PpsR repressor and the PrrBA two-component system. The puc operon is under control of PpsR, FnrL, and PrrBA system. Expression of bchE is controlled by FnrL and PrrBA two-component system, whereas bchF is regulated exclusively by PpsR. It was demonstrated that the PpsR repressor is responsible for high-light repression of bchF and that FnrL might be involved in perceiving the cellular redox state in addition to sensing $O_2$ itself.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.28-32
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• 2003

In order to apply the properties of fiber reinforced plastic(FRP) to support panel of polyurethane foam in LNG storage tank, we estimated the mechanical properties, degree of vapour barrier, chemical stability and thermal conductivity changes as ageing. According to the results, the mechanical strength (i.g. compressive strength, bending strength, tensile strength and shear strength) are more than 30 times higher than those of plywood. The FRP-polyurethane foam(PUF) composites have lower thermal conductivity changes as ageing than plywood-PUF composites. FRP-PUF sandwich composite for LNG storage tank with these remarkable properties are compared the abilities of these structures with those of the conventional structures(plywood-PUF sandwich composite). Finally, we can obtain the effects such as superior mechanical properties and fuel saving through improved ability of vapor barrier.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.137-144
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• 1994

Spherical multicellular aggregates of adult rat hepatocytes (spheroid) which have tissue like structure, were formed and immobilized in the pores of polyurethane foam (PUF) which was used as a culture substratum. These hepatocyte/spheroids, about 100 $\mu\textrm{m}$ in diameter, have maintained higher differentiated functions than those of hepatocyte/monolayer for about 3 weeks in serum-free medium. Then, we designed a prototype module of an artificial liver support system using a PUF/spheroid packed-bed, in which hepatocyte/spheroids were immobilized at high density. The urea synthesis activity of the artificial liver was maintained at least 10 days in 100% rat blood plasma. We start examining the performance of hybrid artificial liver in an ex vivo extracorporeal experiment with an acute hepatic failure rat.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.217-227
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• 2013

Passive air samplers (PAS) have been developed since the early 2000s and widely used for the atmospheric monitoring of persistent organic pollutants (POPs). PAS are useful especially for the investigation of source-receptor relationship of POPs because they provide higher spatial resolution data. In Korea, however, only a few research groups have conducted POPs monitoring using PAS. One of the reasons for the limited application of PAS might be due to a complicated calculation method for air concentration. In this study, therefore, we introduced the principle of polyurethane foam (PUF)-PAS, which has been most widely used in the world, and provided an example of the calculation of air concentration of polycyclic aromatic hydrocarbons (PAHs). As all data tables and equations for this calculation were provided, this method can be used for the conversion of the amount of POPs (ng) in a PUF disk to air concentration ($ng/m^3$).

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.173-176
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• 2020

사물인터넷의 사용이 급격히 증가함에 따라 관련 보안 기술의 개발이 매우 중요하게 되었다. 사물인터넷이 지니는 근본적인 자원 제한 요소 환경을 극복하기 위해, 최근 Chatterjee 기타 등은 정량화된 질의 응답 기반의 PUF를 활용한 인증 프로토콜을 최근 IEEE Transactions on Dependable and Secure Computing 저널에 제안하였다. 그러나 장치 간 세션 키를 주고받는 과정에서 공개된 채널에서 값을 한번 획득한 공격자는 누구나 세션 키를 만들 수 있는 치명적인 취약점이 존재한다. 본 논문에서는 이러한 취약점을 설명하고 정당한 장치만 세션 키를 만들 수 있는 방법을 제시한다.

• Journal of Environmental Health Sciences
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• v.41 no.2
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• pp.116-125
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• 2015

Objective: This study was carried out to use pine needles as a passive air sampler (PAS) for atmospheric polychlorinared dibenzo-p-dioxins/furans (PCDD/Fs). Methods: PCDD/Fs concentrations in ambient air ($C_a$, $pg/m^3$) and deposited pine needles ($C_p$, pg/g dry) were analyzed simultaneously from June 1 to December 31. Air samples were taken using two low volume PUF active air samplers with an overall average air volume of approximately $1,200Sm^3$. Pine needles were collected the end of December near the air sampler. PCDD/Fs was analyzed by HRGC/HRMs. Results: A good correlation was shown ($R^2=0.6357$, p=0.0001) between $C_a$ and $C_p$, but a better correlation ($R^2=0.7372$, p<0.0001) existed between the logarithm of octanol-air partitioning coefficient ($LogK_{oa}$) and Log($C_p/C_a$). The average PCDD/Fs sampling rates from air to pine needles were 0.045($0.018-0.185m^3/day-g\;dry$). Conclusion: It was found that pine needles can be used as PAS for atmospheric PCDD/Fs, and they are especially suitable for long time PAS compared to PUF disk PAS.

• Journal of the Korean Institute of Gas
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• v.8 no.2 s.23
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• pp.1-7
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• 2004

The physical properties of rigid polyurethane foam(PUF) synthesized using various types of blowing agents such as water, HFC-365mfc, HFC-245fa, HCFC-l4lb, CFC-11 and n-pentane were studied. The blending effect of blowing agents were also studied. The thermal conductivity, reaction rate, and cell morphology of the PUF with various blending ratio of blowing agents were investigated. The PUF blown by water shows the highest compressive strength among other single blowing agents. The thermal conductivity of PUFs blown by HFC-245fa and HFC-365mfc are close to that of PUFs blown by CFC-11. When HFC-365mfc was mixed with HFC-245fa(30mo1e$\%$) as coblowing agent, the mechanical property shows the highest value among other coblowing agents. It is that the thermal conductivity of PUFs depends on cell size of PUFs as well as thermal conductivity of blowing agent in gaseous form.

• Journal of Environmental Health Sciences
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• v.38 no.4
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• pp.360-368
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• 2012

Objective: This study was carried out to use pine needles as a passive air sampler (PAS) of atmospheric Polychlorinated Biphenyls (PCBs). Methods: PCB concentrations in ambient air ($C_a$, ng/$m^3$) and deposited on pine needles ($C_p$, ng/g dry) were analyzed simultaneously from June 1 to December 31. Air samples were taken using a low volume PUF active air sampler and the overall average air volume was about 900-1,000 $m^3$. Pine needles were collected at the end of August and December near the air sampler. Results: $C_a$ were higher at higher air temperature and lower chlorinated PCB congeners, but $C_p$ showed irregular distribution. The average PCB sampling rates from air to pine needles were 0.116 (0.002-0.389) $m^3$/day - g dry. Conclusions: A poor correlation was shown between $C_a$ and $C_p$. However, a good correlation was shown between the logarithm of octanol-air partitioning coefficient ($logK_{oa}$) and log ($C_p/C_a$), and the interrelation was better with longer sampling time (June to December) than shorter sampling time (June to August). The average PCB sampling rates from air to pine needles were the lowest with respect to PUF disk, XAD-2 resin and semipermeable membrane devices (SPMDs) PAS. The average ratio ($C_{a-calc}/C_{a-meas}$) of calculated ($C_{a-calc}$) and measured ($C_{a-meas}$) PCB concentration was 0.69 with a shorter sampling time and 1.24 with a longer, so $C_{a-calc}$ was close to $C_{a-meas}$. It was found that pine needles can be used as PAS of atmospheric PCBs, and are especially suitable for long-time PAS.