• BMB Reports
• /
• 제40권6호
• /
• pp.1009-1015
• /
• 2007

In this communication, we report the efficacy of $\beta$-carotene towards differentiation and apoptosis of leukemia cells. Dose ($20{\mu}M$) and time dependence (12 h) tests of $\beta$-carotene showed a higher magnitude of decrease (significance p < 0.05) in cell numbers and cell viability in HL-60 cells than U937 cells but not normal cell like Peripheral blood mononuclear cell (PBMC). Microscopical observation of $\beta$-carotene treated cells showed a distinct pattern of morphological abnormalities with inclusion of apoptotic bodies in both leukemia cell lines. When cells were treated with $20{\mu}M$ of $\beta$-carotene, total genomic DNA showed a fragmentation pattern and this pattern was clear in HL-60 than U937 cells. Both the cell lines, on treatment with $\beta$-carotene, showed a clear shift in $G_1$ phase of the cell cycle. In addition the study also revealed anti-oxidant properties of $\beta$-carotene since there was reduction in relative fluorescent when treated than the control at lower concentration. Collectively this study shows the dual phenomenon of apoptosis and differentiation of leukemia cells on treatment with $\beta$-carotene.

• Journal of Life Science
• /
• 제9권2호
• /
• pp.44-48
• /
• 1999

The ionization of tyrosine residue is known to be involved in the stabilization of transition-state in catalysis of astacin based upon the astacin-transition state analog structure. Two tyrosine residues, Tyr-216 and Tyr-219, are conserved in all MMPs related with astacin family, We replaced Tyr-216 and Tyr-219 into phenylalanine, respectively and the zinc binding properties, kinetic parameters, and pH dependence of each mutant are determined in order to examine the role of tyrosine residue in matrilysin catalysis. Both mutants contain two zinc atoms per mol of enzyme, indicating that either tyrosime does not affect the zinc binding property of the enzyme. Y216F and Y219F mutants are highly active and the kcat/Km values are only decreased 1.1-1.5-fold compared to the wild-type enzyme. The decrease in the activity of the mutants is essentially due to the increase in Km value. The pH dependencies of the kcat/Km values for both mutants are similar to the corresponding dependencies obtained with the wild type enzyme. The pKa values at the alkaline side of both mutants are not changed. These kinetic and pH dependence results indicate that the ionization of active site tyrosine residue of matrilysin is not reflected in the kinetics of peptide hydrolysin as catalyzed by astacin.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
• /
• pp.165-168
• /
• 2003

최근 TV 대응 LCD 제품의 본격적인 양산과 더불어 LCD TV 의 색재현성에 대한 해결과제가 큰 문제로 대두되고 있으며, CRT 급 색재현성의 확보는 LCD TV 의 고급화를 위한 또 하나의 개발 방향이 되고 있다. 그러나, CF(Color Filter)만을 이용한 색재현성의 개선은 근본적으로 한계를 가지고 있으며, 패널 투과율의 저하로 이어져 또다시 고휘도 사양의 BL(Back Light)에 대한 요구가 발생하고 있다. 따라서 본 연구에서는 CF(Color Filter)만에 의한 색재현성의 개선이 아닌 BL 광원 자체의 스펙트럼 최적화를 통해서 CRT 급 색재현성의 확보를 통한 고부가가치 상품개발의 가능성을 제시하고자 하였다. 구체적으로, 램프형광체의 RED 와 Green-Blue 영역에서의 Intensity 향상을 통해서 기존의 CCFL(Cold Cathode Fluorescent Lamp)과는 다른 특성을 광원에 부가하여, 기본의 LCD 패널을 그대로 이용한 경우에도 색재현성을 약 11% 개선하였다.

• 전기학회논문지
• /
• 제57권5호
• /
• pp.833-838
• /
• 2008

Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature. Additionally, spectrum, color temperature and coordination are measured to check that is relation with ambient temperature.

• International Journal of Oral Biology
• /
• 제39권4호
• /
• pp.177-185
• /
• 2014

Transfection is a gene delivery tool that is a popular means of manipulating cellular properties, such as induced pluripotent stem cell (iPSC) generation by reprogramming factors (Yamanaka factors). However, the efficiency of transfection needs to be improved. In the present study, three transfection protocols - non-liposomal transfection (NLT), magnetofection and electroporation - were compared by analysis of their transfection efficiencies and cell viabilities using human dental pulp cells (hDPC) and bovine fetal fibroblasts (bFF) as cell sources. Enhanced green fluorescent protein gene was used as the delivery indicator. For magnetofection, Polymag reagent was administrated. NLT, FuGENE-HD and X-treme GENE 9 DNA transfection reagents were used for NLT. For electroporation, the $Neon^{TM}$ and $NEPA21^{TM}$ electroporators were tested. $Neon^{TM}$ electroporation showed highest transfection efficiency when compared with NLT, magnetofection, and $NEPA21^{TM}$ electroporation, with transfection efficiency of about 33% in hDPC and 50% in bFF, based on viable cell population in each cell type. These results suggest that transfection by $Neon^{TM}$ electroporation can be used to deliver foreign genes efficiently in human and bovine somatic cells.

• 한국컴퓨터정보학회논문지
• /
• 제10권1호
• /
• pp.1-6
• /
• 2005

백색발광은 풀칼라, 백라이트 및 조명을 위한 전자발광 소자로의 응용에 매우 중요하다. 본 논문에서는 오렌지 발광을 내는 Rubrene 색소를 포함하는 청색 재료인 nitro-DPVT 박막을 사용한 단분자 유기 백색발광소자를 구현하였다. 제작된 소자의 기본적 구조는 ${\alpha}-NPD/nitro-DPVT/nitro-DPVT:Rubrene/BCP/Alq3.$이다. 알루미늄은 음극재료로 사용하였으며 양극 재료는 ITO를 사용하였다. 백색 발광 스펙트럼은 가시광선 전 영역에 걸쳐 나타났고 14V에서 발광된 빛의 C.I.E 색좌표는 (0.3347,0.3515)이다. 동작개시 전압은 2.5V이하에서 나타났고 양자효율은 $0.35\%$이었다.

• Bulletin of the Korean Chemical Society
• /
• 제35권2호
• /
• pp.425-430
• /
• 2014

Amyloidogenic proteins often exhibit fibrillar polymorphism through alternative assembly processes, which has been considered to have possible pathological implications. Here, firefly luciferase (LUC) is shown to induce amyloid polymorphism of ${\alpha}$-synuclein, the major constituent of Lewy bodies found in Parkinson's disease, by acting as a novel template. The drastically accelerated fibrillation kinetics of ${\alpha}$-synuclein with LUC required the nucleation center produced by the active enzyme of LUC. Fluorescent dye binding, transmission electron microscopy, and Fourier transformed infrared spectroscopy revealed the morphologically distinctive amyloid fibrils of ${\alpha}$-synuclein prepared in the absence or presence of LUC. As the altered morphological characteristics became inherent to the mature fibrils, those properties were inherited to next-generations via nucleation-dependent fibrillation process. The seed control, therefore, would be an effective means to modify amyloid fibrils with different biochemical characteristics. In addition, the LUC-directed amyloid fibrillar polymorphism also suggests that other cellular biomolecules including enzymes in general are able to diversify amyloid fibrils, which could be self-propagated with diversified biological activities, if any, inside cells.

• Bulletin of the Korean Chemical Society
• /
• 제34권10호
• /
• pp.2905-2908
• /
• 2013

Fluorescent and colorimetric recognition properties of 2-(4-N-phenyl-3-thiosemicarbazone)-8-hydroxyquinoline (1) in buffered aqueous solution (1% DMSO, HEPES 20 mM, pH = 7.4) have been examined. Sensor 1 displays highly selective and sensitive recognition to $Cu^{2+}$ with fluorescence "ON-OFF" performance. The in situ formed 1-$Cu^{2+}$ complex exhibits an excellent selectivity toward sulfide ions with fluorescence "OFF-ON" behavior via $Cu^{2+}$ displacement approach. Thus, relay recognition of $Cu^{2+}$ and sulfide by a known molecule 1 has been achieved.

• 한국전기전자재료학회논문지
• /
• 제17권2호
• /
• pp.217-222
• /
• 2004

The white-light-emitting organic LED(OLED) with two-wavelength was fabricated using the DPVBi of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi/Rubrene/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). We analyzed the fabricated device through the changes of the DPVBi and Rubrene layer's thickness. We obtained the white-light-emitting OLED with white color light and the CIE coordinate of the device was (0.29, 0.33) at applied voltage of 13V when the thickness of DPVBi layer was 210$\AA$ and the thickness of Rubrene layer was 180$\AA$. At a current of 100㎃/$\textrm{cm}^2$, the quantum efficiency was 0.35％ and at a voltage of 20V, it was 0.405％.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2862-2867
• /
• 2008

High-temperature components of gas turbine operated for certain period of time can be reused by being repaired or rejuvenated. In case of the gas turbine combustion liners, the biggest and the most important one in the high-temperature components, come in a repair shop after operated for 8,000 or 12,000 hours according to the model and go through the repair and rejuvenation in order to be reused. A stated combustion liner is the first channel which has the combustion gas reached a nozzle from a fuel nozzle. Materials and coating properties of old and new model combustion liners were investigated. To repair these components after the visual inspection, the coatings of combustion liners were removed and then FPI(Fluorescent Penetrant Inspection), a kind of the NDI(Non-Destructive Inspection), was conducted. Damage patterns and the number of the damaged components were classified and analyzed based on data provided from the visual inspection over a long period of time. Focusing on the difference between old model and new model combustion liners, we analyzed the damage distribution and changes and consequently concluded that new model combustion liner would increase repair rate.