무기 고분자인 폴리실라잔을 이용한 수소 분리막의 합성 및 기공특성

권일민,송인혁,박영조,이재욱,윤희숙,김해두,Kwon, Il-Min,Song, In-Hyuck,Park, Young-Jo,Lee, Jae-Wook,Yun, Hui-Suk,Kim, Hai-Doo 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.5

We investigated the pore properties of inorganic membranes applied for hydrogen separation industry. Inorganic membranes were derived from polysilazanes. The thermal reactions involved were studied using thermogravimetry(TG) and IR spectroscopy(FTIR) of the solids. To determine the thermal effect of pore properties, polysilazanes were pyrolysed in inert atmosphere. Pore volume and BET surface area showed the maximum value at a pyrolysis temperature of $500^{\circ}C$. For amorphous SiCN membrane derived from polysilazanes, selectivity of $H_2/N_2$ was 4.81 at $600^{\circ}C$.

금속이온을 첨가한 TiO2 나노입자의 열처리 온도에 따른 상전이 연구

권일민,문병기,김청식,이병세 한국물리학회 2006 새물리 Vol.52 No.1

Metal-ion-doped and pure TiO$_2$ nanoparticles were prepared by using reverse micelles and a solvothermal process. Mn, Co, Ni, Fe, Cr, Pb, Eu, and Tb ions were doped into TiO$_2$ nanoparticles, and the amount of doping was 2 \% for all the metal ions. The crystalline structures, surface morphologies and phase transitions were investigated according to annealing process by using X-ray diffraction, scanning electron microscopy, and trans mission electron microscopy. Doing with Mn and Co ions was observed to promote a phase transformation from anatase to rutile and enhance the grain growth, whereas doing with Eu and Tb ions was observed to prevent phase the transformation and to inhibit grain growth in the annealing process of the synthesized TiO$_2$ nanoparticles. Reverse micelle 방법과 Solvothermal 방법을 이용하여 순수한 TiO$_2$와 금속이온을 첨가한 TiO$_2$를 합성하였다. 첨가한 금속이온은 Mn, Co, Ni, Fe, Cr, Pb, Eu, Tb 이며, 농도는 2 \%이다. XRD, SEM, TEM을 이용하여 이들의 구조, 표면 형태, 상전이를 조사하였다. 첨가한 Mn, Co 이온은 TiO$_2$의 상전이와 입자의 성장을 촉진한 반면, TiO$_2$에 첨가된 Eu, Tb 이온은 TiO$_2$의 상전이를 지연하고 입자의 성장을 느리게 하였다. Co, Ni, Pb, Eu, Tb 이온이 첨가된 anatase 상의 TiO$_2$에서는 rutile로 상변화를 시작하는 온도에서 새로운 화합물이 석출되었다.

Mammalian Molecular Clocks

권일민,최한경,손기훈,김경진 한국뇌신경과학회 2011 Experimental Neurobiology Vol.20 No.1

As a consequence of the Earth's rotation, almost all organisms experience day and night cycles within a 24-hr period. To adapt and synchronize biological rhythms to external daily cycles, organisms have evolved an internal time-keeping system. In mammals, the master circadian pacemaker residing in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus generates circadian rhythmicity and orchestrates numerous subsidiary local clocks in other regions of the brain and peripheral tissues. Regardless of their locations, these circadian clocks are cell-autonomous and self- sustainable, implicating rhythmic oscillations in a variety of biochemical and metabolic processes. A group of core clock genes provides interlocking molecular feedback loops that drive the circadian rhythm even at the single-cell level. In addition to the core transcription/translation feedback loops, post-translational modifications also contribute to the fine regulation of molecular circadian clocks. In this article, we briefly review the molecular mechanisms and post-translational modifications of mammalian circadian clock regulation. We also discuss the organization of and communication between central and peripheral circadian oscillators of the mammalian circadian clock.

플렉서블 촉각센서 개발을 위한 CNT 기반 PDMS 복합체의 압저항 특성 평가

권일민(I. M. Kwon),권수용(S. Y. Kwon),김민석(M.-S. Kim),박연규(Y-K. Park) 한국정밀공학회 2011 한국정밀공학회 학술발표대회 논문집 Vol.2011 No.6월

Estrogen modulates serotonin effects on vasoconstriction through Src inhibition

김재곤,임영은,권일민,강종순,배영민,조하나 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Estrogen has diverse effects on cardiovascular function, including regulation of the contractile response to vasoactive substances such as serotonin. The serotonin system recently emerged as an important player in the regulation of vascular tone in humans. However, hyperreactivity to serotonin appears to be a critical factor for the pathophysiology of hypertension. In this study, we examined the modulatory mechanisms of estrogen in serotonin-induced vasoconstriction by using a combinatory approach of isometric tension measurements, molecular biology, and patchclamp techniques. 17β-Estradiol (E2) elicited a significant and concentration-dependent relaxation of serotonininduced contraction in deendothelialized aortic strips isolated from male rats. E2 triggered a relaxation of serotonininduced contraction even in the presence of tamoxifen, an estrogen receptor antagonist, suggesting that E2-induced changes are not mediated by estrogen receptor. Patch-clamp studies in rat arterial myocytes showed that E2 prevented Kv channel inhibition induced by serotonin. Serotonin increased Src activation in arterial smooth muscle required for contraction, which was significantly inhibited by E2. The estrogen receptor-independent inhibition of Src by E2 was confirmed in HEK293T cells that do not express estrogen receptor. Taken together, these results suggest that estrogen exerts vasodilatory effects on serotonin-precontracted arteries via Src, implying a critical role for estrogen in the prevention of vascular hyperreactivity to serotonin.

La Doping Effect on the Luminous Properties of YAlO3:Eu3+ Nanophosphors

김정환,최혜영,권일민,정중현,양현경,문병기,이성수 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

Eu3+-doped Y1-xLaxAlO3 nanophosphors were synthesized by using a solvothemal method and the crystallinity and the luminescent properties of those nanophosphors were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser spectroscopy. A yttrium aluminum perovskite (YAP) nanoparticle possesses a cubic perovskite structure phase. With increasing La, the crystallinity changes from a cubic perovskite (x = 0) to a mixed phase of a hexagonal structure (x = 0.8) via a hexagonal perovskite structure (x = 0.4). Since the doped Eu3+ prefers La3+ sites to Y3+ sites, the photoluminescence (PL) spectra of the La-containing samples exhibit radiation from Eu3+ substituted at La3+ sites. As a result, the luminescent lifetime of YAP was 2.4 ms and those of others samples containing La were in the range 1.6 1.8 ms. As the amount of La3+ was increased from x = 0 to 0.05, the band width was broadened by a factor of more than two and the photoluminescence excitation (PLE) peak position dramatically shifted from 237 nm to 290 nm. Both the PLE and the PL peak intensities increased with increasing La concentration.

A splice variant of human Bmal1 acts as a negative regulator of the molecular circadian clock

이지원,박언영,김가혜,권일민,김경진 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Bmal1 is one of the key molecules that controls the mammalian molecular clock. In humans, two isoforms of Bmal1 are generated by alternative RNA splicing. Unlike the extensively studied hBmal1b, the canonical form of Bmal1 in most species, the expression and/or function of another human-specific isoform, hBmal1a, are poorly understood. Due to the lack of the N-terminal nuclear localization signal (NLS), hBMAL1a does not enter the nucleus as hBMAL1b does. However, despite the lack of the NLS, hBMAL1a still dimerizes with either hCLOCK or hBMAL1b and thereby promotes cytoplasmic retention or protein degradation, respectively. Consequently, hBMAL1a interferes with hCLOCK:hBMAL1binduced transcriptional activation and the circadian oscillation of Period2. Moreover, when the expression of endogenous hBmal1a is aborted by CRISPR/Cas9-mediated knockout, the rhythmic expression of hPer2 and hBmal1b is restored in cultured HeLa cells. Together, these results suggest a role for hBMAL1a as a negative regulator of the mammalian molecular clock.

The Mosquito Repellent Citronellal Directly Potentiates Drosophila TRPA1, Facilitating Feeding Suppression

두은주,안태정,최민성,권일민,김형욱,권재영,강경진 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

Citronellal, a well-known plant-derived mosquito repellent, was previously reported to repel Drosophila melanogaster via olfactory pathways involving but not directly activating Transient Receptor Potential Ankyrin 1 (TRPA1). Here, we show that citronellal is a direct agonist for Drosophila and human TRPA1s (dTRPA1 and hTRPA1) as well as Anopheles gambiae TRPA1 (agTRPA1). Citronellal-induced activity is isoform-dependent for Drosophila and Anopheles gambiae TRPA1s. The recently identified dTRPA1(A) and ag- TRPA1(A) isoforms showed citronellal-provoked currents with EC50s of 1.0 ± 0.2 and 0.1 ± 0.03 mM, respectively, in Xenopus oocytes, while the sensitivities of TRPA1(B)s were much inferior to those of TRPA1(A)s. Citronellal dramatically enhanced the feeding-inhibitory effect of the TRPA1 agonist N-methylmaleimide (NMM) in Drosophila at an NMM concentration that barely repels flies. Thus, citronellal can promote feeding deterrence of fruit flies through direct action on gustatory dTRPA1, revealing the first isoform-specific function for TRPA1(A).