• Journal of Photoscience
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• v.9 no.2
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• pp.454-456
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• 2002

It is important to determine the action spectrum of UV-B radiation contained in the sunlight to estimate the risk of skin cancer. We have investigated action spectra for induction of apoptosis and reproductive cell death in L5178Y cells using the Okazaki Large Spectrograph at NIBB. L5178Y cells were exposed to light at different wavelengths in UV-B or UV-A region. Frequencies of apoptosis induction and reproductive cell death were determined by counting cells with chromatin condensation, and by the colony formation assay, respectively. The measured sensitivity spectra for the two end-points were in very good agreement. Sensitivity decreased steeply with increase of wavelength in UV-B region and remains nearly constant in UV-A region. The action spectra were also slightly steeper than that for the minimum erythematic dose (MED), but very similar to the light absorption spectrum of DNA in UV-B region. On the other hand, the spectra for both endpoints were similar to MED spectrum but not DNA spectrum in the UV-A region. Also different time-course and morphological difference of apoptosis were found between UV-B (long time, fragmentation) and UV-A (short time, shrinkage) region. These results suggest that DNA damage induced by UV-B light triggers apoptosis and reproductive cell death, but other damaged targets (membrane, protein and so on) trigger these effects in UV-A region.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.89-91
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• 2015

Observed spectra of stars around the Sun have indicated that the Sun is located in a gas cavity, extending to 100pc. This gas cavity is called the "Local Bubble". The density of the interstellar medium (ISM) in the local bubble is about one tenth that of the average for the ISM in the Milky Way. Furthermore, some structures such as gas planes and strings in the local bubble are probably the result of supernovae. These, due to their low temperatures, can not be observed in the visible and infrared. The only way to do so is to measure the spectra of nearby stars so that the light of stars passing through the local bubble is absorbed by existing gas and the resulting spectral lines from absorption can be measured. In this study, we use binary stars to trace the local bubble structures through lines such as the Na I Doublet. First, we determined the observed spectral lines of stars by HARPS and FEROS echelle spectrographs. Then, we made synthetic spectra with the ATLAS9 code. Finally, the difference between the observational and synthetic spectra confirms the existence of the Na I Doublet in the local ISM.

• Textile Coloration and Finishing
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• v.5 no.2
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• pp.91-98
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• 1993

The silk fabrics were treated with color solution extracted from leaf of Camellia. The depression effect of destruction and yellowing of silk treated with color solution, shift of UV-VIS spectra of color solution, color difference of silk fabrics by dyeing with acid dyes and drycleaning fastness of silk treated with color solution were studied. UV-VIS spectra appeared to hypsochromic shift by irradiation. The decrease of tensile strength and the elongation of the silk treated with color solution showed depressed but those of untreated silk increased by irradiation. The yellowness index of silk treated with color solution showed a little change by irradiation. The color difference after dyeing with several acid dyes on treated and untreated silk showed not remarkable changes. Dsrycleaning fastness of silk treated by color solution was excellent.

• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1991-1997
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• 2019

In this manuscript, we present a method for the direct calculation of an ambient dose equivalent (H^* (10)) for the external gamma-ray exposure with an energy range of 40 keV to 2 MeV in an electronic personal dosimeter (EPD). The designed EPD consists of a 3 × 3 ㎟ PIN diode coupled to a 3 × 3 × 3 ㎣ CsI (Tl) scintillator block. The spectrum-to-dose conversion function (G(E)) for estimating H^* (10) was calculated by applying the gradient-descent method based on the Monte-Carlo simulation. The optimal parameters for the G(E) were found and this conversion of the H^* (10) from the gamma spectra was verified by using ²⁴¹Am, ¹³⁷Cs, ²²Na, ⁵⁴Mn, and ⁶⁰Co radioisotopes. Furthermore, gamma spectra and H^* (10) were obtained for an arbitrarily mixed multiple isotope case through Monte-Carlo simulation in order to expand the verification to more general cases. The H^* (10) based on the G(E) function for the gamma spectra was then compared with H^* (10) calculated by simulation. The relative difference of H^* (10) from various single-source spectra was in the range of ±2.89%, and the relative difference of H^* (10) for a multiple isotope case was in the range of ±5.56%.

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.298-302
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• 2001

A site preference of niobium atom in Rb2-xLa2Ti3-xNbxO10 (0.0 $\leq$ x $\leq1.0)$ and RbLa2-xCaxTi2-xNb1+xO10 (0.0 $\leq$ x $\leq2.0)$, which are the solid-solutions between Rb2La2Ti3O10 and RbCa2Nb3O10, has been investigated by Raman spectroscopy. The Raman spectra of Rb2-xLa2Ti3-xNbxO10 (0.0 $\leq$ x $\leq1.0)$ gave an evidence that niobium atoms substituted for titanium atoms preferably occupy the highly distorted outer octahedral sites rather than the central ones in triple-octahedral perovskite layers. In contrast, the Raman spectra of RbLa2-xCaxTi2-xNb1+xO10 (0.0 $\leq$ x $\leq2.0)$ showed no clear information for the cationic arrangement in perovskite slabs. This difference indicated that a site preference of niobium atoms is observed only when the linear Rb-O-Ti linkage can be replaced by much stronger terminal Nb-O bond with double bond character. From comparison with the Raman spectroscopic behavior of CsLa2-xA’xTi2-xNb1+xO10 (A’ = Ca and Ba; 0.0 $\leqx\leq2.0)$, it is also proposed that a local difference in arrangement of interlayer atoms causes a significantly different solid acidity and photocatalytic activity of the layered perovskite oxides, despite their crystallographically similar structures.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.263-266
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• 2002

We have developed a practical method for estimating high-energy x-ray spectra using measured attenuation curves. This method is based on the iterative perturbation technique proposed by Waggener et al. The principle is to minimize the difference between the measured and calculated transmission curves. The experimental study was made using 4 MV, 10 MV, and 15 MV x-ray beams. It has been found that the spectrum varies strongly with the off-axis distance.

• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1470-1474
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• 2003

The dynamics of the tertiary conformation of myoglobin (Mb) after photolysis of carbon monoxide was investigated at 283 K solution by probing amide I and II bands using femtosecond IR absorption spectroscopy. Time-resolved spectra in the amide region evolve with 6-12 ps time scale without noticeable subpicosecond dynamics. The spectra measured at 100 ps delay after photolysis is similar to the difference FTIR spectrum at equilibrium. Time-resolved spectra of photoexcited Mb evolve modestly and their amplitudes are less than 8% of those of photolyzed MbCO, indicating that thermal contribution to the spectral evolution in the amide region is negligible. These observations suggest that the conformational relaxation ensuing photolysis of MbCO be complex and the final deoxy protein conformation have been substantially formed by 100 ps, probably with 6- 12 ps time constant.

• Journal of Plant Biology
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• v.30 no.4
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• pp.267-276
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• 1987

A pollen analytical study was carried out on the accumulated humus samples collected from 27 sites under the different plant communities of Mt. Seolag. These pollen spectra were then compared with the actual vegetation. The aboreal pollen(AP) and non-abnoreal pollen(NAP) were 1 Family 25 Genus and 5 Family 5 Genus, respectively. Among the aboreal pollen identified, the pollen of Pinus, Quercus, Betula and Acer were appeared in abundance and the coniferous pollen of Pinus was occupied at least 20%-65% through all the sites studied. The pollens of Abies, Betula, accer, Quercus, Carpinus, Corylus, Fraxinus, Styrax, Prunus and Ericaceae were in accordance with the present vegetation but the other pollens were inconsistent with the actual vegetaton. It suggests that it was caused by the difference between Wehseolag and Namseolag of subalpine zone in Mt. Seolag was 200 m by pollen spectra. Quercus was distributed at the lower part of Namseolag and the subalpine boreal elements were increased with increasing altitudes. The pollen spectra of each site was put together into 5 groups of pollen assemblage by cluster analysis and the community coefficient (CC) was over 60% between all sites studied.

• Imaging Science in Dentistry
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• v.39 no.2
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• pp.61-68
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• 2009

Purpose : The purpose of this study was to develop the radiographic technique for detecting the demineralization which is known as indication of dental caries. Materials and Methods: This technique was based on the comparing of multiple radiographs which was irradiated by multiple X-ray spectra. For the meaningful comparing, the multiple radiographs were reconstructed to the dosimetrically consistent images using a standard material. The difference of resulting images of same target with multiple spectra represents the difference of response of material as regards the spectra. Results : We have found about 10% of demineralization of dental hard tissues particularly in the proximal region through the analyzing of differences. Conclusion: Most intriguing thing in this investigation was that the method to analyze difference shows us to an anatomic structure of dental hard tissues even if absolute values of optical density were excluded during the procedures. (Korean J Oral Maxillofac Radiol2009; 39: 61-8)

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.190-200
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• 2023

As the field of application of in-situ gamma spectroscopy is diversified, proficiency is required for consistent and accurate analysis. In this study, a program was developed to virtually create gamma energy spectra of artificial nuclides, which are difficult to obtain through actual measurements, for training. The virtual spectrum was created by synthesizing the spectra of the background radiation obtained through actual measurement and the theoretical spectra of the artificial radionuclides obtained by a Monte Carlo simulation. Since the theoretical spectrum can only be obtained for a given geometrical structure, representative major geometries for in-situ measurement (ground surface, concrete wall, radioactive waste drum) and the detectors (HPGe, NaI(Tl), LaBr₃(Ce)) were predetermined. Generated virtual spectra were verified in terms of validity and harmonization by gamma spectrometry and energy calibration. As a result, it was confirmed that the energy calibration results including the peaks of the measured spectrum and the peaks of the theoretical spectrum showed differences of less than 1 keV from the actual energies, and that the calculated radioactivity showed a difference within 20% from the actual inputted radioactivity. The verified data were assembled into a database and a program that can generate a virtual spectrum of desired condition was developed.