• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.853-858
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• 2014

We propose a fabrication method for polydiacetylene (PDA)-embedded hydrogel microfibers on a microfluidic chip. These fibers can be applied to the detection of cyclodextrines (CDs), which are a family of sugar and aluminum ions. PDA, a family of conjugated polymers, has unique characteristics when used for a sensor, because it undergoes a blue-to-red color transition and nonfluorescence-to-fluorescence transition in response to environmental stimulation. PDAs have different sensing characteristics depending on the head group of PCDA. By taking advantage of ionic crosslinking-induced hydrogel formation and the 3D hydrodynamic focusing effect on a microfluidic chip, PCDA-EDEA-derived diacetylene (DA) monomer-embedded microfibers were successfully fabricated. UV irradiation of the fibers afforded blue-colored PDA, and the resulting blue PDA fibers underwent a phase transition to red and emitted red fluorescence upon exposure to CDs and aluminum ions. Their fluorescence intensity varied depending on the CDs and aluminum ion concentrations. This phase transition was also observed when the fibers were dried.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.859-864
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• 2013

Aim: To compare the effectiveness of self-examination, clinical examination and screening methods using 1% toluidine blue and Lugol's iodine in estimating the prevalence of lesions at risk of malignancy and oral malignant disease amongst the male inmates of Yerwada Central Jail, Pune. Material and Methods: Study was carried out on male inmates in two phases. In the first phase self-examination and clinical examination was carried out on 2,257 male inmates. 164 suspicious cases were subjected to phase II of the study out of whom, 82 participants were screened with 1% toluidine blue and 2% Lugol's iodine followed by biopsy procedure. Results: Sensitivity and specificity for self-examination with clinical examination was 92.2% and 96.6% respectively. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) and positive (+LR) and negative likelihood ratio (-LR) for Toluidine Blue were 88.1%, 66.6% 97.1%, 30%, 2.63 and 0.17 respectively while for Lugol's Iodine they were 94.7%, 83.8%, 98.6%, 55.5%, 5.67 and 0.06 respectively. Conclusions: Prevalence of lesions at risk of malignancy and oral malignant disease by self-examination was 7.8% and by clinical examination was 6.3%. Self-examination is an effective tool in early detection of oral cancer. Use of Lugol's iodine as a screening tool for oral lesions is highly effective in inmate populations.

• Advances in materials Research
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• v.13 no.3
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• pp.243-251
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• 2024

The asymmetric polylactic acid (PLA) membrane was prepared via phase inversion method using non-solvent induced separation (NIPS) technique. This study aims to synthesized as well as to characterize the PLA membrane and evaluating the membrane performance on water flux and permeability. In addition, this research also studied the removal performance of methylene blue dye. The polymer solution has been prepared using 12 wt.% of PLA and dissolved in 88 wt.% of Dimethylacetamide (DMAc) as a solvent. Then, the cast film was immersed in different ratio of coagulant bath medium (distilled water: methanol: ethanol) ranging from 100:0:0, 75:25:0, 75:0:25 and 75:12.5:12.5, respectively). Several characterizations were performed which include, membrane contact angle and membrane porosity. Performance PLA membranes were determined in terms of water flux and permeability at 1 bar transmembrane pressure using dead-end permeation cell. Finally, methylene blue (MB) removal efficiency was tested at the same transmembrane pressure. The findings revealed that the increase of alcohol concentration in coagulant bath resulted in higher porosity and lower contact angle. In short, MB dye rejection efficiency is also closely related to the amount of alcohol ratio used in coagulant baths. Increases in concentration of methanol and ethanol in coagulant bath medium increases the membrane porosity thus increased in efficiency of methylene blue rejection.

• Journal of Life Science
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• v.19 no.2
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• pp.249-255
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• 2009

Esculetin, a coumarin compound, has been known to inhibit proliferation and induce apoptosis in several types of human cancer cells. However, the molecular mechanisms involved in esculetin-induced apoptosis are still uncharacterized in human leukemia cells. In this study, we have investigated whether esculetin exerts anti-proliferative and apoptotic effects on human leukemia U937 cells. It was found that esculetin could inhibit cell viability in a time-dependent manner, which was associated with the induction of apoptotic cell death such as increased populations of apoptotic- sub G1 phase. Apoptosis of U937 cells by esculetin was associated with an inhibition of Bcl-2/Bax binding activity, formation of tBid, down-regulation of X-linked inhibitor of apoptotic protein (XIAP) expression, and up-regulation of death receptor 4 (DR4) and FasL expression. Esculetin treatment also induced the degradation of ${\beta}$-catenin and DNA fragmentation factor 45/inhibitor of caspase-activated DNase (DFF45/ICAD). Furthermore, a caspase-3 specific inhibitor, z-DEVD-fmk, significantly inhibited sub-G1 phase DNA content, morphological changes and degradation of ${\beta}$-catenin and DEE45/ICAD. These results indicated that a key regulator in esculetin-induced apoptosis was caspase-3 in human leukemia U937 cells.

• Journal of The Korean Astronomical Society
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• v.17 no.1
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• pp.37-49
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• 1984

UBV photoelectric observations were carried out for bright stars in M67 and the masses of clump stars and giant stars were derived in M67 and the other old open clusters, NGC 188, NGC 2420, NGC 2506 and IC 4651. The mean mass of clump stars in the five clusters ranges $m=0.5{\sim}1.0m_{\odot}$, and its ratio to the mean mass of giant stars is about 0.83. The number ratio of blue stragglers to the stars brighter than the turn-off of main sequence increases with cluster age whereas that of clump stars decreases with age. These results imply that the clump stars and blue stragglers are at the phase of horizontal branch evolution.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1350-1352
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• 2008

Research on down conversion phosphor materials is the key for the development of solid state lighting (SSL). Especially finding alternative red phosphor for white LEDs based on blue or NUV LEDs are important research task. Under this view, we have synthesized a series of $Eu^{3+}$ substituted $La_2W_{2-x}Mo_xO_9$ (x = 0 ~ 2, insteps of 0.1) red phosphor and characterized by X-ray diffraction (XRD) and photoluminescence. XRD results reveal a phase transition from triclinic to cubic structure for $x\;{\geq}\;0$. All the compositions show broad charge transfer band due to charge transfer from oxygen to tungsten/molybdenum and red emission due to $Eu^{3+}$ ions. Select compositions show high red emission intensity compared to the commercial red phosphor under NUV/blue ray excitation. Hence, this candidate can be possible red emitting phosphors for white LEDs.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.569-572
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• 2003

Titanium dioxide ($TiO_2$) nanoparticles were prepared by the oxidation of titanium tetrachloride ($TiCl_4$) in a diffusion flame reactor. The average diameter of particles was 15 to 30 nm and mass fraction of anatase ranged from $40\;to\;80\%$. Effects of particle size and phase composition of those $TiO_2$ nanoparticles on photocatalytic properties such as decomposition of methylene blue and bacteria gas were investigated. The degree of decomposition of methylene blue by the $TiO_2$ nanoparticles under the illumination of the black light was directly proportional to the anantase mass fraction, but inversely to the particle size. The decomposition of bacteria by the $TiO_2$ nanoparticles under the illumination of the fluorescent light showed the same trend as in the case of the methylene blue.

• Journal of Pharmaceutical Investigation
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• v.4 no.1_2
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• pp.46-54
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• 1974

A new spectrophotemetric method was estalished for the determination of oleic acid. This method is based on the 1,2-dichloroe-thane extraction of the ion-pair formed between methylene blue and oleic acid. But the absorbance of an ion-pair in the 1,2-dichloroe-thane layer was variable with the temperature, the ion-pair was extracted back into a diluted hydrochloric acid solution. The maximum absorbance of the acid extract observed at $660m{\mu}$ and a lineal relationship was observed from the initial amount over the range of $50-800{\gamma}/ml$ of oleic acid in the aqueous phase. The composition ratio of the ion-pair formed between methylene blue and oleic acid was determined to be 2 : 1 by both the mole ratio and continuous variation methods.

• Journal of the Korean Applied Science and Technology
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• v.23 no.2
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• pp.153-159
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• 2006

The photocatalytic degradation of methylene blue(MB) was investigated using $TiO_2$ as photocatalyst and UV radiation. $TiO_2$ supported with activated carbon(AC) was prepared by SOL-GEL method and depended on several parameters such as the mass ratio of $TiO_2/AC$, pH and experimental time. The presence of the anatase and rutile crystal phase was determined by XRD analyses of the prepared $TiO_2$. The degradation of MB with $TiO_2/AC$ was about 20% higher than that of AC alone. A variation of photodegradation was negligible under UV radiation conditions ( ${\geq}$ 40W). It was experimentally showed that the photodegradation rate was increased with increasing the amount of photocatalyst. The optimal catalyst was prepared by impregmation of $5wt%-TiO_2$ with AC and was calcined at $300^{\circ}C$, and showed about 99% removal efficiency for 3hrs.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.612-616
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• 1991

Metachromatic behavior of methylene blue (MB) in solutions of aqueous sodium dodecyl sulfate (SDS), chondroitin sulfate and L-${\alpha}$-lecithin vesicle at $18~52^{\circ}$C has been studied by absorption spectroscopy. MB was clustered in the matrix of the vesicle with high concentration of L-${\alpha}$-lecithin. The metachromasy of MB was found to be independent of phase transition temperature of vesicles. These results suggest that the dyes were aggregated on the hydrophilic surfaces of vesicle. In the vesicular system, the metachromatic effect of MB was dramatically decreased in the presence of hexadecyltrimethylammonium bromide (CTAB) than SDS. It is estimated that the intercalation site of these surfactants on vesicle surfaces was different, that is, the intercalation of CTAB was more effective than that of SDS.