• 센서학회지
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• 제33권1호
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• pp.40-47
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• 2024

The creation of vertically aligned one-dimensional (1D) nanostructures through the decoration of n-type tin oxide (SnO₂) on p-type chromium oxide (Cr₂O₃) constitutes an effective strategy for enhancing gas sensing performance. These heterostructures are deposited in multiple stages using a glancing angle deposition technique with an electron beam evaporator, resulting in a reduction in the surface porosity of the nanorods as SnO₂ is incorporated. In comparison to Cr₂O₃ films, the bare Cr₂O₃ nanorods exhibits a response 3.3 times greater to 50 ppm H₂S at 300℃, while the SnO₂-decorated Cr₂O₃ nanorods demonstrate an eleven-fold increase in response. Furthermore, when subjected to various gases (CH₄, H₂S, CO₂, H₂), a notable selectivity toward H₂S is observed. This study paves the way for the development of p-type semiconductor sensors with heightened selectivity and sensitivity towards H₂S, thus advancing the prospects of gas sensor technology.

• 한국환경과학회지
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• 제17권2호
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• pp.233-237
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• 2008

The objective of this study was conducted to evaluate the effects of poultry litter amendments on pH and soluble reactive phosphorus (SRP) in poultry litter. Two laboratory studies were conducted for 42 d in Exp. 1 and for 10 d in Exp. 2, respectively. The poultry litter was treated with various amendments which included 4 g fly ash and 4 g $AlCl_3\;(AlCl_36H_2O)/100g$ litter in Exp. 1 and 4 g alum$(Al_2(SO_4){_3}\;14H_2O)$, 8 g alum, 8.66 g liquid alum, and 17.3 g liquid alum/100 g litter in Exp. 2; untreated litter served as controls. There were no differences in pH between control and T1(4 g fly ash) and SRP contents between T1(4 g fly ash) and T2(4 g $AlCl_3$) in Exp. 1. A significant difference in pH and SRP contents in Exp. 2 was observed among all treatments(P< 0.05). In experiment 1, T1(4 g fly ash) and T2(4 g $AlCl_3$) at 42 d decreased SRP in litter by 47.1% and 62.6% of that from litter alone, respectively. In experiment 2, T1(4 g alum), T2(8.66 g liquid alum), T3(8 g alum), and T4(17.3 g liquid alum) treatments at 10 days reduced SRP contents by up to 36.2%, 62.9%, 87.0%, and 83.9%, respectively, when compared with the controls. Decrease in SRP contents was chiefly associated with reduction in litter pH. These results indicate that use of various litter amendments to limit P solubility has potential and should be pursued as a means of reducing soluble reative phosphorus during short term.

• International Journal of Oral Biology
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• 제39권2호
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• pp.97-105
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• 2014

The aim of this study was to determine the beneficial effect of propofol on human keratinocytes that have undergone hypoxia reoxygenation (H/R) injury and to investigate whether autophagy is associated with the protective mechanism. Thus, we evaluated how propofol influences the intracellular autophagy and apoptosis during the H/R process in the HaCaT cells. The cultured human keratinocyte cells were exposed to 24 h of hypoxia (5% $CO_2$, 1% $O_2$, 94% $N_2$) followed by 12 h of reoxygenation (5% $CO_2$, 21% $O_2$, 74% $N_2$). The experiment was divided into 4 groups: (1) Control=Normoxia ; (2) H/R=Hypoxia Reoxygenation ; (3) PPC+H/R=Propofol Preconditioning+Hypoxia Reoxygenation; (4) 3-MA+PPC+ H/R=3-MA-Methyladenine+Propofol Preconditioning+ Hypoxia Reoxygenation. In addition, Western blot analysis was performed to identify the expression of apoptotic pathway parameters, including Bcl-2, Bax, and caspase 3 involved in mitochondrial-dependent pathway. Autophagy was determined by fluorescence microscopy, MDC staining, AO staining, and western blot. The H/R produced dramatic injuries in keratinocyte cells. In our study, the viability of Propofol in H/R induced HaCaT cells was first studied by MTT assay. The treatment with 25, 50, and $100{\mu}M$ Propofol in H/R induced HaCaT cells enhanced cell viability in a dose-dependent manner and $100{\mu}M$ was the most effective dose. The Atg5, Becline-1, LC3-II, and p62 were elevated in PPC group cells, but H/R-induced group showed significant reduction in HaCaT cells. The Atg5 were increased when autophagy was induced by Propofol, and they were decreased when autophagy was suppressed by 3-MA. These data provided evidence that propofol preconditioning induced autophagy and reduced apoptotic cell death in an H/R model of HaCaT cells, which was in agreement with autophagy playing a very important role in cell protection.

• 공업화학
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• 제21권5호
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• pp.590-592
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• 2010

본 연구에서는 리튬 2차 전지의 양극물질 중 하나인 Li-Mn spinel ($LiMn_2O_4$)을 합성하기 위해 전구체로 K-Birnessite ($K_xMnO_2{\cdot}{yH_2O}$)를 이용하였다. K-Birnessite는 과망간산칼륨[$KMnO_4$]과 우레아[$CO(NH_2)_2$]를 사용하여 수열합성법으로 합성하였고, K-Birnessite와 LiOH를 수열 반응시켜 Li-Mn spinel 나노입자를 제조하였다. 리튬함량에 따른 Li-Mn spinel 의 구조 및 형상 변화와 전기화학적 특성에 대한 경향성을 알아보기 위해 LiOH와 K-Birnessite의 몰 비를 조절하여 Li-Mn spinel를 합성하였다. 합성된 분말은 X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetry (TG)를 이용하여 물질의 구조 및 형상을 분석하였고, 정전류법으로 양극재의 용량과 율 특성을 비교 분석하였다. 그 결과 LiOH/K-Birnessite의 몰 비가 0.8일 때 가장 큰 용량($117\;mAhg^{-1}$)을 나타냈고, 몰 비가 증가할수록 Li-Mn spinel 중 리튬함량이 증가하여 용량은 감소하였으나, 입자크기는 작아져서 율 특성은 점점 향상되는 경향을 보였다.

• Fisheries and Aquatic Sciences
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• 제19권1호
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• pp.1.1-1.6
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• 2016

Although soft tunic syndrome (STS) in the ascidian is a serious disease, helpful measures have yet not been established. It was examined in this study by applying aniti-parasitic drugs to eradicate the causative protozoa Azumiobodo hoyamushi from infected ascidians. Formalin was synergistic in killing parasites in vitro when co-treated with hydrogen peroxide ($H_2O_2$) or bronopol, but not with chloramine-T or povidone-iodine (PVP-I), when tested with in vitro parasite culture. The synergistic effects did not change when $formalin-H_2O_2$ (or bronopol) ratios were changed. It was found that treatment periods less than 60 min achieved a sub-maximal efficacy. Increasing drug concentration while keeping 30 min period improved anti-parasitic effects. Anti-parasitic effects of $formalin(F)+H_2O_2$(H) were also assessed in an in vivo STS model infected with cultured parasites. It was observed that combined 50 (40F + 10H) and 100 (80F +20H) ppm were effective in partially preventing STS-caused mortality. In horizontally transmitted artificial STS model, significant prevention of ascidian mortality was also observed after 50 ppm. Marked reduction of living parasites were noted after drug treatments in vivo. The results provide a highly useful basis to develop a preventive or treatment measure against the currently uncontrollable STS in the ascidian.

• 생명과학회지
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• 제32권4호
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• pp.310-317
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• 2022

최근 인체에 유해한 요인으로 대기오염의 주성분인 미세먼지에 대한 관심이 증가하고 있다. 특히 직경이 2.5 ㎛ 미만인 PM_2.5는 인간의 폐 상피세포에서 자가포식을 동반한 산화적 스트레스를 유발하는 것으로 알려져 있다. 그러나 PM_2.5가 산화적 스트레스 하에서 자가포식을 증가시키는지와 이 과정이 ROS 의존적인지에 대한 연구는 충분하지 않은 실정이다. 본 연구에서는 PM_2.5가 인간 폐 상피 A594 세포에서 ROS 생성을 통해 자가포식을 촉진하는지를 조사하였다. 우리의 결과에 의하면, PM_2.5와 H₂O₂를 함께 처리한 세포에서는 각각이 단독 처리된 세포에 비하여 세포 생존력이 유의적으로 감소하였으며, 이는 전체 및 미토콘드리아 ROS 생성의 증가와 관련이 있었다. 또한, PM_2.5와 H₂O₂의 동시 처리는 Cyto-ID 염색을 통해 확인된 바와 같이 자가포식 유도의 증가와 LC3, p62 및 beclin 1과 같은 자가포식 바이오 마커 단백질의 발현을 증가시켰다. 그러나 NAC의 전처리에 의하여 ROS의 생성을 인위적으로 차단하였을 경우, PM_2.5와 H₂O₂의 동시 처리에 의한 세포 생존율의 감소와 자가포식 유도는 현저하게 억제되었다. 따라서, PM_2.5에 의해 유도된 ROS 생성이 A549 세포에서 자가포식 유도에 중요한 역할을 할 것으로 추측되며, 이는 PM_2.5에 의해 유도될 수 있는 폐 기능 손상이 산화적 스트레스 하에서 더욱 증가할 수 있음을 의미한다.

• Archives of Pharmacal Research
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• 제20권3호
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• pp.259-263
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• 1997

In the preparation of acyclic thymidine nucleoside analogues, $K_2CO_3$(or NaH) treated thymine in DMSO was alkylated with .omega.-chloroalkyl nitrite (Cl-(CH_2)n-CN; n=1, 2, 3, 4) to provide an isomeric mixture of 1-(${\omega}$-cyanoalkyl)thymine (2a-d) and 1,3-bis(${\omega}$-cyanoalkyl)thymine in approximately 5:1 ratios. Reduction of the cyano function 2a-d with $NaBH_{4}/CoCl_{2}$ center dot$ 6H_{2}O$gave the corresponding 1-(${\omega}$aminoalkyl)thymine (3a-d). The newly formed primary amino function in 3a-d was directly reacted with 2-chloroethylisocyanate to afford the 1-[.omega.($N^{I}$-2-chloroethylureido) alkyl]thymine (4a-d) in good yields. Nitrosation of 1-[5-($ N^{I}-2$-chloroethylureido)pentyl] thymine (4d) with glacial acetic acid and dry $NaNO_{2}$-powder in anhydrous $CH_{2}Cl_{2}$gave two types of regioisomeric nitrosoureas, 1-[5-($N^{I}$--chloroethyl-$N^{I}$--nitrosoureido)pentylithymine (5d) and 1-[5-($N^{I}-2$-chloroethyl-N-nitrosoureido)pentyllthymine in approximately 5 :1 ratios. The in vitro cytotoxicity of the synthesized compounds (2a-d, 3a-d, 4a-d and 5a-d) against three cell lines (K-562, P-388 and FM-3A) are measured as $IC^{50}$ values. Compounds 3b and 4c showed moderate activities against all three cell lines, and all other compounds were found to be not active.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.582-588
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• 2014

3 mol% Co-added $Ni(OH)_2$ fine powders, which showed ${\beta}$-phase, as positive electrode materials have been fabricated using $NiSO_4{\cdot}6H_2O$ aqueous solution by ultrasonic spray-chemical precipitation and subsequent hydrothermal method, and sheet-like Ni nanopowder was fabricated by mechano-chemical reduction method. The addition effects of the sheet-like Ni nanopowder on the electrochemical properties of the positive electrode in Ni-Zn Redox flow battery were investigated. Impedance spectroscopy revealed that the addition of the sheet-like Ni nanopowder resulted in decrease in the electrical resistivity; 10 wt.% addition reduced the electrical properties by a fifth. Cyclic voltammetry showed the addition of the sheet-like Ni nanopowder resulted in decrease in the potential difference of oxidation and reduction; this means the increase in the reversability for electrode reduction. Charge/discharge measurement confirmed that the addition of the sheet-like Ni nanopowder resulted in the increase in the discharge efficiency.

• Applied Biological Chemistry
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• 제40권6호
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• pp.567-571
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• 1997

절화의 수확 후 저장 및 유통과정 중에서 야기될 수 있는 문제 중의 하나인 굴지성 반응에 의한 화경의 구부러짐을 막아내기 위하여 CDTA, $CoCl_2$ 및 ortho-vanadate의 절화 굴지성 반응 억제 효과를 검정하였다. 절화의 굴지성 반응억제제 처리는 절화줄기 기부 혹은 굴지성 반응 부위를 시험용액에 담구는 두가지 방법에 의거 실시하였다. 절화기부를 저해제 용액에 1시간 침지시키는 방법으로 처리하였을 경우, P-type ATPase 저해제인 vanadate만 굴지성 반응 억제효과를 보였으나, 절화의 굴지성반응 활성부위를 직접 계면활성제 (Triton X-100, 0.01%)가 녹아있는 저해제 용액에 침지하였을 경우 CDTA 및 vanadate처리구에서도 상당한 정도의 굴지성 억제를 관찰 할 수 있었을 뿐만 아니라 특히 $CoCl_2$ 처리구에서 그 효과가 현저하였다. $CoCl_2$ 농도에 따른 굴지성 반응 억제효과의 변화를 조사한 결과, 20 mM 전후의 농도에서 거의 완벽한 효과를 볼 수 있었다. 이상의 결과를 고려해 볼 때, 적절한 계면활성제와 $CoCl_2$를 이용한 처리액을 준비하여 활성부위에 직접처리하는 방법을 개선한다면 산업적 응용성이 높은 절화의 굴지성 억제 수단을 마련할 수 있다는 결론을 얻었다.

• Carbon letters
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• 제25권
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• pp.33-42
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• 2018

Activated carbon (AC) was modified by ammonium persulphate or nitric acid, respectively. AC and the modified materials were used as catalyst supports. The oxygen groups were introduced in the supports during the modifications. All the supports were characterized by $N_2$-physisorption, Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis. Methanol synthesis catalysts were prepared through wet impregnation of copper nitrate and zinc nitrate on the supports followed by thermal decomposition. These catalysts were measured by the means of $N_2$-physisorption, X-ray diffraction, XPS, temperature programmed reduction and TEM tests. The catalytic performances of the prepared catalysts were compared with a commercial catalyst (CZA) in this work. The results showed that the methanol production rate of AC-CZ ($23mmol-CH_3OH/(g-Cu{\cdot}h)$) was higher, on Cu loading basis, than that of CZA ($9mmol-CH_3OH/(g-Cu{\cdot}h)$). We also found that the modification methods produced strong metal-support interactions leading to poor catalytic performance. AC without any modification can prompt the catalytic performance of the resulted catalyst.