• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.225-232
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• 2011

Reactive ion etching (RIE) technique for maskless surface texturing of mc-silicon solar wafers has been applied and succeed in fabricating a grass-like black-silicon with an average reflectance of $4{\pm}1%$ in a wavelength range of 300~1,200 nm. In order to investigate the optimized texturing conditions for mass production of high quantum efficiency solar cell Surface characteristics such as the spatial distribution of average reflectance, micrscopic surface morphology and minority carrier lifetime were monitored for samples from saw-damaged $15.6{\times}15.6\;cm^2$ bare wafer to key-processed wafers as well as the mc-Si solar cells. We observed that RIE textured wafers reveal lower average reflectance along from center to edges by 1% and referred the origin to the non-uniform surface structures with a depth of 2 times deeper and half-maximum width of 3 times. Samples with anti-reflection coating after forming emitter layer also revealed longer minority carrier lifetime by 40% for the edge compared to wafer center due to size effects. As results, mc-Si solar cells with RIE-textured surface also revealed higher efficiency by 2% and better external quantum efficiency by 15% for edge positions with higher height.

• Radiation Oncology Journal
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• v.36 no.3
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• pp.241-247
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• 2018

Purpose: A hybrid-dynamic conformal arc therapy (HDCAT) technique consisting of a single half-rotated dynamic conformal arc beam and static field-in-field beams in two directions was designed and evaluated in terms of dosimetric benefits for radiotherapy of lung cancer. Materials and Methods: This planning study was performed in 20 lung cancer cases treated with the VERO system (BrainLAB AG, Feldkirchen, Germany). Dosimetric parameters of HDCAT plans were compared with those of three-dimensional conformal radiotherapy (3D-CRT) plans in terms of target volume coverage, dose conformity, and sparing of organs at risk. Results: HDCAT showed better dose conformity compared with 3D-CRT (conformity index: 0.74 ± 0.06 vs. 0.62 ± 0.06, p < 0.001). HDCAT significantly reduced the lung volume receiving more than 20 Gy (V₂₀: 21.4% ± 8.2% vs. 24.5% ± 8.8%, p < 0.001; V₃₀: 14.2% ± 6.1% vs. 15.1% ± 6.4%, p = 0.02; V₄₀: 8.8% ± 3.9% vs. 10.3% ± 4.5%, p < 0.001; and V₅₀: 5.7% ± 2.7% vs. 7.1% ± 3.2%, p < 0.001), V₄₀ and V₅₀ of the heart (V₄₀: 5.2 ± 3.9 Gy vs. 7.6 ± 5.5 Gy, p < 0.001; V₅₀: 1.8 ± 1.6 Gy vs. 3.1 ± 2.8 Gy, p = 0.001), and the maximum spinal cord dose (34.8 ± 9.4 Gy vs. 42.5 ± 7.8 Gy, p < 0.001) compared with 3D-CRT. Conclusions: HDCAT could achieve highly conformal target coverage and reduce the doses to critical organs such as the lung, heart, and spinal cord compared to 3D-CRT for the treatment of lung cancer patients.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.16-39
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• 1995

From July 8 to September 2 1994, asbestos exposure level among asbestos textile workers was surveyed. Six plants out of plants in Korea were selected for this study. In addition to the exposure level, the relationship between the level of exposure and some factors affecting exposure were studied. Also, using historical data of asbestos concentrations in asbestos textile plants plus current data, trend of asbestos exposure level could be introduced. Historical exposure level was estimated on the basis of these data. The main results of this study are follows. 1. Average concentration of all six plants surveyed was 1.54 f/cc, and range of those concentrations was 0.03 - 11.58 f/cc. The minimum average concentration was 0.32 f/cc and the maximum was 8.04 f/cc which is four times higher than the Korean standard. A wide difference of exposure level among the workers of different plants was observed. In three plants, the half of all the plants surveyed, their average concentrations exceeded the Korean standard, and those in all the plants exceeded the ACGIH TLV. 2. Among total 56 samples, 22 samples(39%) were in excess of the Korean standard, and 53 samples(95%) were above the ACGIH TLV. Among 32 personal samples, 15 samples(47%) exceeded the Korean standard, and 30 samples(94%) exceeded the ACGIH TLV. Among 24 area samples excluding a few samples collected in office area, seven samples exceeded the Korean standard, and 23 samples( 96%) exceeded the ACGIH TLV. 3. Distributions of concentrations were observed by processes. In weaving, the highest, average concentration was 4.29 f/cc, and range was 2.61 - 11.58 f/cc. In spinning, average concentration was 2.22 f/cc, and range was 0.41 - 8.93 f/cc. In carding, average concentration was 1.98 f/cc, and range was 0.23 - 10.93 f/cc, In twisting, average concentration was 1.65 f/cc, and range was 0.21 - 9.83 f/cc. In mixing, the lowest, average concentration was 0.48 f/cc, and range was 0.22 - 1.20 f/cc. 4. All the samples from basic processes of asbestos textile plants were above the ACGIH TLV. Nineteen samples(45%) out of all these 42 samples exceeded Korean standard. Fourteen samples(58%) of total 24 personal samples, and five samples(28%) of total 18 area samples exceeded the Korean standard. Considering processes, all the samples in weaving process exceeded the Korean standard and 50 did 54% of those in spinning, 40% in carding, and 27% in twisting. 5. Trend of decreasing asbestos concentrations in asbestos textile plants was observed by time. 6. Asbestos concentrations in asbestos textile plant in 1975 were estimated to be 11.0 - 92.4 f/cc.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.215-222
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• 2016

X-ray mammography is the most effective method for the diagnosis of calcified lesions of various breast diseases. To reduce patient dose and to obtain optimal image required for diagnosis, the performance of the mammography system should be maintained continuously. Because the target (anode) angle of the X-ray tube is measured from the central X-ray, the effective angle can be slightly different in view of the position on the detector, which can result in degrading spatial resolution of the imaging within the field of view. In this study, we measured the MTF to examine spatial resolution for positions on the detector in the digital mammography system. For a tungsten wire of $50{\mu}m$ diameter, the highest spatial frequency was obtained. It meant that a wire diameter for measuring MTF through LSF should be small compared to the pixel size of the detector used in the mammography system. The spatial resolution showed slightly different performance according to positions on the detector. The center position gave the best spatial resolution and positions away from the center showed the degraded performance although the difference of the spatial resolution was small. The effective focal spot size of the full width at half maximum also showed similar result. It concluded that the slightly increase of the effective focal spot size gave the degradation of the spatial resolution for positions on the detector.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.167-174
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• 1987

Among noninvasive approaches for the evaluation of left ventricular performance, radionuclide ventriculography (RVG) has been shown to be of particular values. Phase analysis, recently introduced as more objective means for evaluating the temporal sequence of systolic ventricular wall motion than cine image of RVG comprises a pixel by pixel Fourier transformation of the time activity curve of a multiple gated acquisition equilibrium blood pool study. To examine the regional wall motion of ventricles in myocardial infarctions, we evaluated the phase image and histogram constructed for each ventricle by total phase angle range and full width of half maximum (FWHM). This study consisted of 7 normal subjects and 23 subjects with acute myocardial infarction. Contrast ventriculography and coronary angiography was performed in all partients with myocardial infarction. And we compared the result of phase analysis with cine image of RVG and examined the interrelationship between phase analysis and contrast ventriculography with coronary angiography. The results were as follows; 1) The total phase angle range and FWHM of LV phase histogram in myocardial infarction ($86^{\circ}\;and\;32^{\circ}$, repectively) were wider than those in normal control ($38^{\circ}\;and\;18^{\circ}$, respectively p<0.01). 2) RV phase angle range and FWHM in patients with right coronary artery (RCA) occlusion ($79^{\circ}\;and\;37^{\circ}$, respectively) were wider than those in normal control ($39^{\circ}\;and\;18^{\circ}$, respectively p<0.001) and the patients without RCA occlusion ($52^{\circ}\;and\;19^{\circ}$, respectively p<0.01). 3) Phase analysis was more sensitive (95%) than cine image of RVG (70%) for the detection of regional wall motion abnormality of LV.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.100-105
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• 1972

This experiment was conducted to investigate the combined effects of radiation and antiseptics on the keeping qualities of pork sausage, which was treated with potassium sorbate and AF-2(2-(-2-furyl)-3-(5-nitro-2-furyl)-acrylamide), and then followed by gamma radiation of 0.25, 0.5, and 0.75 Mrad. Amounts of treated antiseptics were a quarter, half, and full levels of their maximum permissible concentration. Irradiated and unirradiated sausages were stored for 50 days at $5^{\circ}C\;and\;25^{\circ}C$, and their changes in rancidity, volatile basic nitrogen, bacterial counts, pH, and sensory analysis were examined during the storage period. The results obtained are as follows: 1) Preservative effects of antiseptics were manifested at cold storage; antiseptics treatment of a quarter-level and unirradiation following low-temperature storage showed the same good keeping qualities as the combined treatment of full-level antiseptics and radiation of 0.25 Mrad following high-temperature storage. 2) There did not appear to recognize irradiation-odor, while color and odor were deteriorated intensively by storage temperature. Sausage irradiated with 0.75 Mrad has shown slightly noticeable off-odor at the end of storage at $25^{\circ}C$. 3) The most suitable radiation dose was considered to be 0.5 Mrad, which could extend the storage life about $2{\sim}3$ times longer than untreated.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.35-41
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• 2006

Possible application of hurdle technology extention of shelf-life of fresh-cut apples was investigated by evaluating various hurdle factors known to be effective microbial growth inhibitors and their synergistic effects. Fresh-cut apples treated with chitooligosaccharide or grapefruit seed extract (GSE) showed higher microbial counts than those treated with distilled water during latter half of storage period, and at high concentrations. Citric and malic acids showed similar results, although microbial counts of fresh-cut apples treated with 0.75% or higher concentration of citric acid increased at 4 days of storage at $18^{\circ}C$, indicating malic acid is more effective than all hurdles tested for controlling microbial growth. Using ascorbic acid and calcium chloride as additional hurdles to control browning and softening, minimum and maximum compositions of dipping solution were: 0.25 : 0.5 : 0.25% and 0.75 : 1.0 : 0.75% malic acid: ascorbic acid: calcium chloride, respectively.

• Journal of Nutrition and Health
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• v.9 no.3
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• pp.18-25
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• 1976

To explain the change of the pungent principles of red pepper, capsaicin, during storage, the relation between infecting mold and capsaicin was studied. Results obtained were summarized as follows; 1. Superior strains which showed good growth and high decomposition activity in their culture broths, Aspergillus oryzae and Aspergillus sp. KF-7 were obtained from the contaminated red pepper fruits. 2. The weight of dry matter was increased at low concentration of capsaicin $(2{\sim}3{\mu}g/ml)$ but it was decreased at high concentration. 3. The residual capsaicin in the culture medium was reduced as half as such after 1 week, and almost disappeared after 2 weeks. At $30^{\circ}C$ and $pH\;7{\sim}9$ of culturing condition, the amounts of reducing capsaicin reached to the maximum. 4. At ground red pepper fruits as culture medium, Aspergillus sp. KF-7 could not glow at all, but Aspergillus oryzae showed good growth at 13% of moisture contents and the residual of capsaicin of red pepper fruits after 40days of cultivation time was 45%. 5. At ground red pepper fruits seed as culture medium, Aspergillus oryzae and Aspergillus sp. KF-7 showed good growth, and the residual of capsaicin after 4 weeks of cultivation time was 55% and 38% respectively.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.555-559
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• 1997

The three different batches of an oral sustained release melatonin (MT) delivery system were prepared by aqueous-based fluid-bed coating of the sugar spheres for the evaluation of in vitro release characteristics and plasma concentration profiles in human subjects. The MT contents in 20% coated sugar spheres of three batches (B1, B2 and B3) were $3.3{\pm}0.08$, $2.4{\pm}0.1$ and $2.5{\pm}0.13$ mg per gram of coated sugar spheres, respectively. The release profiles of three different batches had a very similar fashion. However, the release profiles of three different batches had a very similar fashion. However, the release half-lives $(T_{50%})$ of MT from B1, B2 and B3 was $3.70{\pm}0.2$, $5.2{\pm}0.2$ and $4.9{\pm}0.07h$, respectively. Plasma concentration profiles of sustained release 0.2mg melatonin-loaded sugar spheres containing 10% immediate release melatonin in gelatin capsules (B1 and B2) were then evaluated in human subjects. The in vivo plasma concentration profies of the two batches (B1 and B2) were very similar each other and located between the physiological endogenous ranges. The time to reach the peak concentration $(T_max)$ was more advanced in case of B1 when compared to B2. However, there was no statistically significant difference in the maximum concentration $(C_max)$ and the area under the curve (AUC) between B1 and B2. The AUC of melatonin-loaded sugar spheres containing 10% and 20% immediate release MT in human subjects had a good linearity between dose and AUC, regardless of the fraction of immediate release MT, indicating the first order elimination process of MT within these doses. The current oral sustained release MT delivery system may be utilized to treat circadian rhythm disorders if it is proven to be more clinically useful when compared to immediate release MT.

• Molecules and Cells
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• v.42 no.3
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• pp.270-283
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• 2019

This study was aimed to explore if lncRNA MALAT1 would modify chemo-resistance of non-small cell lung cancer (NSCLC) cells by regulating miR-197-3p and p120 catenin (p120-ctn). Within this investigation, we totally recruited 326 lung cancer patients, and purchased 4 NSCLC cell lines of A549, H1299, SPC-A-1 and H460. Moreover, cisplatin, adriamycin, gefitinib and paclitaxel were arranged as chemotherapies, and half maximal inhibitory concentration (IC50) values were calculated to evaluate the chemo-resistance of the cells. Furthermore, mice models of NSCLC were also established to assess the impacts of MALAT1, miR-197-3p and p120-ctn on tumor growth. Our results indicated that MALAT1 and miR-197-3p were both over-expressed within NSCLC tissues and cells, when compared with normal tissues and cells (P < 0.05). The A549, H460, SPC-A-1 and SPC-A-1 displayed maximum resistances to cisplatin ($IC50=15.70{\mu}g/ml$), adriamycin ($IC50=5.58{\mu}g/ml$), gefitinib ($96.82{\mu}mol/L$) and paclitaxel (141.97 nmol/L). Over-expression of MALAT1 and miR-197-3p, or under-expression of p120-ctn were associated with promoted viability and growth of the cancer cells (P < 0.05), and they could significantly strengthen the chemo-resistance of cancer cells (P < 0.05). MALAT1 Wt or p120-ctn Wt co-transfected with miR-197-3p mimic was observed with significantly reduced luciferase activity within NSCLC cells (P < 0.05). Finally, the NSCLC mice models were observed with larger tumor size and weight under circumstances of over-expressed MALAT1 and miR-197-3p, or under-expressed p120-ctn (P < 0.05). In conclusion, MALAT1 could alter chemo-resistance of NSCLC cells by targeting miR-197-3p and regulating p120-ctn expression, which might assist in improvement of chemo-therapies for NSCLC.