• Korean journal of food and cookery science
• /
• v.17 no.2
• /
• pp.156-164
• /
• 2001

Four different oligosaccharides used to determine their effects on gelatinization and retrogradation of Backsulgies(BSG), Korean traditional rice cake, were cyclodextrin, isomaltooligosaccharide, fructooligosaccharide and maltotetrose, with 3 or 6%(w/w), based on the rice flour. From the Amylograph and blue value data, adding 6% cyclodextrin into the rice flour fastened the gelatinzation process, and delayed the retrogradation in stored BSG at 4$\^{C}$ for up to 3 days, probably due to its cyclic structure. Using rheometer, the hardness of freshly made BSG added with cyclodextrin was significantly lower than that of control BSG, and increased with storage time in all BSGs at refrigerated temperature. When using maltotetrose in rice flour, the hardness of BSG was also significantly low, but slightly higher than that of cyclodextrin. Hunter “L” value in BSG decreased with the addition of oligosaccharides, but the higher the level of oligosaccharide in BSG, the insignificant the Hunter “a”,“b” values of BSG. From the X-ray diffraction studies, the rice flour showed typical A pattern, and the crystallinities of all BSG gave amorphous V type. The highest peaks of X-ray patterns in BSG added with 6% cyclodextrin or maltotetrose were, however, lower than that of the control, meaning the less crystalline, retrograded starch in the former BSGs. Based on sensory evaluation, BSG added with all oligosacchrides were not significantly different in taste, flavor, chewiness, moistness and overall preferences, with slightly darker color with longer storage time, compared to the control BSG.

• Journal of the Korean institute of surface engineering
• /
• v.53 no.6
• /
• pp.271-279
• /
• 2020

Non-ferrous metals, widely used in the mechanical industry, are difficult to machine, particularly by drilling and tapping. Since non-ferrous metals have a strong tendency to adhere to the cutting tool, the tool life is greatly deteriorated. Diamond-like carbon (DLC) is one of the promising candidates to improve the performance and life of cutting tool due to their low frictional property. In this study, a sacrificial DLC layer is applied on the hard nitride coated drill tool to improve the durability. The DLC coatings are fabricated by controlling the acceleration voltage of the linear ion source in the range of 0.6~1.8 kV. As a result, the optimized hardness(20 GPa) and wear resistance(1.4 x 10-8 ㎣/N·m) were obtained at the 1.4 kV. Then, the optimized DLC coating is applied as an sacrificial layer on the hard nitride coating to evaluate the performance and life of cutting tool. The Vickers hardness of the composite coatings were similar to those of the nitride coatings (AlCrN, AlTiSiN), but the friction coefficients were significantly reduced to 0.13 compared to 0.63 of nitride coatings. The drilling test were performed on S55C plate using a drilling machine at rotation speed of 2,500 rpm and penetration rate of 0.25 m/rev. The result showed that the wear width of the composite coated drills were 200 % lower than those of the AlCrN, AlTiSiN coated drills. In addition, the cutting forces of the composite coated drills were 13 and 15 % lower than that of AlCrN, AlTiSiN coated drills, respectively, as it reduced the aluminum clogging. Finally, the application of the DLC sacrificial layer prevents initial chipping through its low friction property and improves drilling quality with efficient chip removal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.11-11
• /
• 2010

Thin-film-transistors (TFTs) that can be deposited at low temperature have recently attracted lots of applications such as sensors, solar cell and displays, because of the great flexible electronics and transparent. Transparent and flexible transistors are being required that high mobility and large-area uniformity at low temperature [1]. But, unfortunately most of TFT structures are used to be $SiO_2$ as gate dielectric layer. The $SiO_2$ has disadvantaged that it is required to high driving voltage to achieve the same operating efficiency compared with other high-k materials and its thickness is thicker than high-k materials [2]. To solve this problem, we find lots of high-k materials as $HfO_2$, $ZrO_2$, $SiN_x$, $TiO_2$, $Al_2O_3$. Among the High-k materials, $Al_2O_3$ is one of the outstanding materials due to its properties are high dielectric constant ( ~9 ), relatively low leakage current, wide bandgap ( 8.7 eV ) and good device stability. For the realization of flexible displays, all processes should be performed at very low temperatures, but low temperature $Al_2O_3$ grown by sputtering showed deteriorated electrical performance. Further decrease in growth temperature induces a high density of charge traps in the gate oxide/channel. This study investigated the effect of growth temperatures of ALD grown $Al_2O_3$ layers on the TFT device performance. The ALD deposition showed high conformal and defect-free dielectric layers at low temperature compared with other deposition equipments [2]. After ITO was wet-chemically etched with HCl : $HNO_3$ = 3:1, $Al_2O_3$ layer was deposited by ALD at various growth temperatures or lift-off process. Amorphous InGaZnO channel layers were deposited by rf magnetron sputtering at a working pressure of 3 mTorr and $O_2$/Ar (1/29 sccm). The electrodes were formed with electron-beam evaporated Ti (30 nm) and Au (70 nm) bilayer. The TFT devices were heat-treated in a furnace at $300^{\circ}C$ and nitrogen atmosphere for 1 hour by rapid thermal treatment. The electrical properties of the oxide TFTs were measured using semiconductor parameter analyzer (4145B), and LCR meter.

• Journal of Sensor Science and Technology
• /
• v.6 no.4
• /
• pp.328-336
• /
• 1997

The CdSe thin films were grown on the Si(100) wafers by a hot wall epitaxy method (HWE). The source and substrate temperature are $600^{\circ}C$ and $430^{\circ}C$ respectively. The crystalline structure of epilayers was investigated by double crystal X-ray diffraction(DCXD). Hall effect on the sample was measured by the van der Pauw method and studied on the carrier density and mobility dependence on temperature. From Hall data, the mobility was increased in the temperature range 30K to 150K by impurity scattering and decreased in the temperature range 150k to 293k by the lattice scattering. In order to explore the applicability as a photoconductive cell, we measured the sensitivity(${\gamma}$), the ratio of photocurrent to darkcurrent(pc/dc), maximum allowable power dissipation(MAPD), spectral response and response time. The results indicated that the photoconductive characteristic were the best for the samples annealed in Cu vapor compare with in Cd, Se, air and vacuum vapour. Then we obtained the sensitivity of 0.99, the value of pc/dc of $1.39{\times}10^{7}$, the MAPD of 335mW, and the rise and decay time of 10ms and 9.5ms, respectively.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.04a
• /
• pp.111-111
• /
• 2019

Glycyrrhizae radix is one of the most frequently prescribed ingredients in Oriental medicine, and G. radix extract has been shown to exert anti-cancer effects. However, the cellular and molecular mechanisms of apoptosis by G. radix are poorly defined. In the present study, it was examined the biochemical mechanisms of apoptosis by water extract of G. radix (WEGR) in human bladder T24 cancer cells. It was found that WEGR could inhibit the cell growth of T24 cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies, DNA fragmentation and increased populations of annexin-V positive cells. The induction of apoptotic cell death by WEGR was connected with an up-regulation of pro-apoptotic Bax protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins (XIAP, cIAP-1 and cIAP-2). In addition, apoptosis-inducing concentrations of WEGR induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. WEGR also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the down-regulation of total Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that WEGR may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.12
• /
• pp.1708-1716
• /
• 2016

The Akt/mammalian target of the rapamycin (mTOR) pathway is activated in the majority of human cancers. Activation of the Akt/mTOR pathway confers resistance to many types of cancer therapy. In this study, we evaluated the apoptotic effect of ethanol extract of Artemisia annua L. through down-regulation of Akt signal pathways and the mitochondrial pathway in hepato-carcinoma cells (HepG2). A. annua extract is known as a medicinal herb that is effective against cancer. We evaluated anti-proliferative activity by MTT-based viability assay and apoptotic effect by Annexin-V/PI staining, mitochondrial membrane potential (MMP), and caspase-3/7 activity as determined by flow cytometry. A. annua treatment led to loss of MMP, resulting in cytochrome c-inducible activation of caspase-3/7. Treatment with A. annua extract reduced activities of Akt/mTOR/anti-apoptotic proteins (such as Bcl-2 and $Bcl-X_L$), leading to increased activation of tumor suppressor p53 and pro-apoptotic proteins (such as Bax and Bak). We applied LY294002 (inhibitor of Akt) and rapamycin (inhibitor of mTOR) to determine the relationship between signal transduction of proteins associated with apoptosis. LY294002 and rapamycin significantly reduced cell viability and increased apoptosis. These results indicate that Bcl-2 and caspase-3 are key regulators in A. annua extract-induced apoptosis in HepG2 cells and are controlled through the Akt/mTOR signaling pathway.

• The Korean Journal of Nuclear Medicine
• /
• v.38 no.4
• /
• pp.318-324
• /
• 2004

Purpose: Philips GEMINI is a newly introduced whole-body GSO PET/CT scanner. In this study, performance of the scanner including spatial resolution, sensitivity, scatter fraction, noise equivalent count ratio (NECR) was measured utilizing NEMA NU2-2001 standard protocol and compared with performance of LSO, BGO crystal scanner. Methods: GEMINI is composed of the Philips ALLEGRO PET and MX8000 D multi-slice CT scanners. The PET scanner has 28 detector segments which have an array of 29 by 22 GSO crystals ($4{\times}6{\times}20$ mm), covering axial FOV of 18 cm. PET data to measure spatial resolution, sensitivity, scatter fraction, and NECR were acquired in 3D mode according to the NEMA NU2 protocols (coincidence window: 8 ns, energy window: $409[\sim}664$ keV). For the measurement of spatial resolution, images were reconstructed with FBP using ramp filter and an iterative reconstruction algorithm, 3D RAMLA. Data for sensitivity measurement were acquired using NEMA sensitivity phantom filled with F-18 solution and surrounded by $1{\sim}5$ aluminum sleeves after we confirmed that dead time loss did not exceed 1%. To measure NECR and scatter fraction, 1110 MBq of F-18 solution was injected into a NEMA scatter phantom with a length of 70 cm and dynamic scan with 20-min frame duration was acquired for 7 half-lives. Oblique sinograms were collapsed into transaxial slices using single slice rebinning method, and true to background (scatter+random) ratio for each slice and frame was estimated. Scatter fraction was determined by averaging the true to background ratio of last 3 frames in which the dead time loss was below 1%. Results: Transverse and axial resolutions at 1cm radius were (1) 5.3 and 6.5 mm (FBP), (2) 5.1 and 5.9 mm (3D RAMLA). Transverse radial, transverse tangential, and axial resolution at 10 cm were (1) 5.7, 5.7, and 7.0 mm (FBP), (2) 5.4, 5.4, and 6.4 mm (3D RAMLA). Attenuation free values of sensitivity were 3,620 counts/sec/MBq at the center of transaxial FOV and 4,324 counts/sec/MBq at 10 cm offset from the center. Scatter fraction was 40.6%, and peak true count rate and NECR were 88.9 kcps @ 12.9 kBq/mL and 34.3 kcps @ 8.84 kBq/mL. These characteristics are better than that of ECAT EXACT PET scanner with BGO crystal. Conclusion: The results of this field test demonstrate high resolution, sensitivity and count rate performance of the 3D PET/CT scanner with GSO crystal. The data provided here will be useful for the comparative study with other 3D PET/CT scanners using BGO or LSO crystals.

• Korean Journal of Community Nutrition
• /
• v.13 no.3
• /
• pp.418-425
• /
• 2008

The purpose of this study was to investigate correlations between bone mineral density (BMD) and dietary and non-dietary factors in female college students. The BMD of the subjects (n = 38) was measured using DEXA (Dual Energy X-ray Absorptiometry) at lumbar spine and three femoral sites including femoral neck, ward's triangle, and femoral trochanter. Three-day 24-hour dietary recall data were collected from each subject to assess consumption levels of nutrients and food groups. The mean (${\pm}SD$) values of age, age of menarche, height, weight, body mass index (BMI), waist-to-hip ratio (WHR), fat mass, and % body fat of the subjects were 21.34 (${\pm}1.73$) years, 13.1 (${\pm}1.2$) years, 161.3 (${\pm}5.0$) cm, 53.7 (${\pm}7.2$) kg, 20.6 (${\pm}2.6$) $kg/m^2$, 0.80 (${\pm}0.04$), 15.4 (${\pm}4.4$) kg, and 28.2 (${\pm}4.7$), respectively. The BMD values of lumbar spine, femoral neck, ward's triangle, and femoral trochanter as T-value were $1.150{\pm}0.13\;g/cm^2$, $0.932{\pm}0.11\;g/cm^2$, $0.850{\pm}0.13\;g/cm^2$, and $0.721{\pm}0.10\;g/cm^2$, respectively. The daily mean energy intake of the subjects was 1660.6 kcal. The intake levels of carbohydrate, calcium, iron, vitamin C, and folic acid were lower than the KDRIs, while those of fat, phosphorus, sodium, vitamin A, and vitamin $B_6$ were higher than the KDRIs. Significantly negative correlation were detected between consumption of fat and oils and the BMD of all sites measured (p < 0.05). Potato and starch intake was negatively correlated to the BMD of femoral neck and word's triangle (p < 0.05). The intake of cereals was found to be negatively correlated to the BMD of ward's triangle (p v 0.05). There was also negative correlation of intake of soybeans and products with the BMD of lumbar spine (p < 0.05). Weight and muscle mass were positively correlated to the BMD of both lumbar spine and femurs (p < 0.01). Significantly positive correlations between BMI, and fat mass and the BMD of lumbar spine were observed (p < 0.001). Additionally fat mass was positively correlated to the BMD of femoral neck. WHR and % body fat were positively correlated to the BMD of lumbar spine (p < 0.05). Negative correlation was found between a serum calcium level and the BMD of femoral neck (p < 0.05). In summary non-dietary factors generally showed significant correlations with the BMD of lumbar spine, while several dietary factors showed significant correlations with the BMD of femurs.

• Proceedings of the KSAR Conference
• /
• 2001.03a
• /
• pp.61-61
• /
• 2001

The main goal of this study was to produce transgenic piglets by the method of injection of sperm-mediated exogenous DNA. Spermatozoa (1$\times$106 sperm of final concentration) obtained from caudal epididymis were mixed with pBC1-hEPO (20 ng/${mu}ell$) or pcDNA3 LAC Z (20 ng/${mu}ell$), and followed by electroporation (500 V, 25 ㎌). Matured oocytes having the first polar body and dense cytoplasm were selected and centrifuged at 12,000g for 6 min. After sperm injection, the oocytes were activated electrically (1.7 ㎸/cm, 30 $\mu$ sec, single pulse) in 0.3 M mannitol solution. Eggs injected sperm were cultured in NCSU 23 medium (0.4% BSA) at 39$^{\circ}C$, 5% $CO_2$ in air for 192 h. This study were comprised 3 experiments. Experiment 1 compared the developmental efficiencies between the sperm-injected oocytes (Group 1) and further activated electrically (Group 2). Experiment 2 compared the expression of pcDNA3 LAC Z in the embryos produced by Group 1 and Group 2. Finally, experiment 3 carried out transfer of embryos (1-8 cell stage) transfected with pBC1 -hEPO into surrogate recipients synchronized by injection of combination of PG600 with hCG. The rates of cleavage and development into blastocyst stage in Group 2 were significantly higher than those of Group 1 (71.3% and 28.1% vs. 43.3% and 10.3%, respectively, p<0.05). Thirty (24.2%) out of 124 embryos analyzed in Group 2 were positive by X-gal. Similarly, in Group 1, 16.3% (8/49) were positive. After transfer of 789 embryos to 7 recipient gilts, three out of them examined by ultrasound became pregnant. One recipient is in day 50 pregnancy. On day 54 of gestation, two were carried out uterotomy in order to confirm the pregnancy One had 7 and another had 2 fetuses. We conclude that injection of sperm-mediated gene transfer will be used as a valuable tool for the production of transgenic piglets.

• Journal of Embryo Transfer
• /
• v.13 no.1
• /
• pp.11-19
• /
• 1998

This study was to determine the effect of ionomycin and 6-dimethylaminopurine (6-DMAP) and/or elcetrical stimulation on the oocyte activation and production of rabbit nuclear transplant embryos. The oocytes were collected from the oviduct of superovulated rabbits at 14 h post hCG injection and cultured in TCM-199 containing 10% FBS until 19 h post hCG injection. To determine the optimum concentration and exposure time of 6-DMAP, some oocytes were activated with 5 $\mu$M ionomycin for 5 min and then in 2.0 mM 6-DMAP for 0.5 to 3.0 h, or in 1.0 to 3.0 mM 6-DMAP for 2.0 h. Other control oocytes were stimulated electrically(3X, 1.25 kV/cm, 60 $\mu$sec) in 0.3 M mannitol solution supplemented with 100 $\mu$M CaCl$_2$ and MgCl$_2$. The nuclear donor embryos of 8-cell stage were synchronized to G$_1$ phase of 16-cell stage, and the recipient cytoplasms were obtained from removal of the first polar body and a portion of membrane bound cytoplasm of the oocytes collected at 15 h post hCG injection. A separated blastomere was injected into the perivitelline space of the enucleated oocytes. The oocytes injected with nucleus were cultured until 19 h post hCG and then electrofused and activated by electrical stimulation with or without ionomycin and 6-DMAP. These nuclear transplant embryos were cultured in TCM-199 containing 10% FBS in 39˚C, 5% CO2 incubator for 120 h. For the oncytes activated parthenogenetically with electrical stimulation with or with-out ionomycin and the various concentration of exposure time of 6-DMAP, the highest cleavage(92.3%) and development to blastocyst stage(41.0%) were resulted from the oocytes activated by ionomycin and 2.0 mM 6-DMAP for 2.0 h, which were found to be significantly(P<0.05) higher than the cleavage(45.2%) and developement to blastocyst stage(14.3%) from the oocytes activated with electrical stimulation. The significantly(P<0.05) more oocytes(71.4%) developed to 4 cell stage at 24 h post activation by ionomycin and 6-DMAP than those by electrical stimulation(18.9%). For the nuclear transplant embryos, the cleavage rate was similarly high in oocyte activation by electrical stimulation with(79.4%) or without ionomycin and 6-DMAP(70.5%). However, the embryo development to blastocyst stage was significantly(P<0.05) higher in oocyte activation by electrical stimulation with ionomycin and 6-DMAP(44.4%) than by electrical stimulation only(25.0%). The significantly(P<0.05) more nuclear transplant embryos(45.6%) developed to 4 cell stage at 18 h post activation by electrical stimulation with ionomycin and 6-DMAP than those by electrical stimulation only(10.6%). These results indicated that the supplemental oocyte activation by ionomycin and 6-DMAP with electrical stimulation enhanced and accelerated the preimplanted in vitro development of the rabbit nuclear transplant embryos.