• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.87-95
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• 2017

The increase in the frequency of occurrence of abnormal weather could include severe rainfall, which could cause rice submergence during the ripening stage. This experiment was conducted to clarify the effects of submergence during the ripening period on yield and quality of rice. The flooding treatment was conducted at 7 and 14 days after heading. Flooding conditions were created with two conditions, flag leaf exposed and overhead flooding, and each condition was divided into two conditions according to water quality-clear and muddy. Although the yield decrease was more severe at 7 days after heading because of the decrease in the ripening ratio, the head rice ratio was more affected at 14 days after heading because of the increase in the chalky kernel ratio. The maximum quantum yield (Fv/Fm), which indicates the photosynthetic efficiency, did not differ before and after the flooding treatment until flooding continued for 4 days. In addition, stem elongation occurred because of flooding as an avoidance mechanism in japonica rice. This phenomenon was expected to decrease the supply of assimilation products to the spikelet (sink). Overall, it was suggested that additional experiments should be conducted examining the change in the starch synthesis mechanism and transfer of assimilate products resulting from submergence, for development of cultivation techniques corresponding to submergence and breeding of varieties with submergence tolerance characteristics.

• BMB Reports
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• v.42 no.9
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• pp.586-592
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• 2009

The bactenecin is an antibacterial peptide with an intramolecular disulfide bond. We recently found that homodimeric bactenecin exhibits more potent antibacterial activity than the monomeric form and retains its activity at physiological conditions. Here we assess the difference in the modes of antibiotic action of homodimeric and monomeric bactenecins. Both monomeric and dimeric bactenecins almost completely killed both Staphylococcus aureus and E. coli within 10-30 min at concentrations of $8-16\;{\mu}M$. However, exposure to liposomes elicited an increase in the fluorescence quantum yield from a tryptophan-containing monomeric analog, while the homodimeric analog showed a significant reduction in fluorescence intensity. Moreover, unlike the monomer, the homodimer displayed apparent membrane-lytic activity enabling release of various sized dyes from liposomes, and rapidly and fully depolarized the S. aureus membrane. Together, our results suggest that homodimeric bactenecin forms pores in the bacterial membrane, while monomeric one penetrates through the membrane to target intracellular molecules/organelles.

• Journal of Korea Foresty Energy
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• v.23 no.1
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• pp.19-25
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• 2004

This study was performed to investigate the growth and photosynthetic rate of ten-years old Pinus koraiensis and Pinus rigida in Banwol industrial region comparing with those of the control site in Gwangju, Gyeonggi Province. Surface soil of the damaged site in pH 4.2 was more acidic than control site in pH 4.8, assuming the accelerated soil deterioration by acid deposition. The shoot growth, needle survival rate and net photosynthetic rate of P. koraiensis and P. rigida at the damaged site were lower than at the control site. In addition, the quantum yield and chlorophyll a+b and b contents reduced in damaged treatment. These results suggest that an inhibition of photochemical reaction of P. koraiensis and P. rigida at the damaged site of Banwol industrial region could be attributed to combined influence of atmospheric pollution and soil acidification.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.441-447
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• 1985

Several benzanilides were prepared by acylation of anilines with substituted benzoyl chlorides. While 2-chlorobenzanilides were photocyclized, 2-methylbenzanilide and 2'-methylbenzanilide were cleaved to give photo-Fries type products. 2-Nitrobenzanilide and 2'-nitrobenzanilide were inert in the above conditions due to lowering energy of the excited state by the nitro group. N, N-dibenzoylaniline and N, N-di-(2-chlorobenzoyl) aniline gave photo-Fries type reaction products effectively. In the benzanilide photo-Fries type reaction the excited singlet state was believed to be involved, since no oxygen effect was observed on the reaction rate. Quantum yield for 2-methylbenzanilide is higher in nonpolar and less viscous solvents than in polar and viscous solvents. The solvent cage radical pair is suggested in the photo-Fries type reaction of benzanilides.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.312-321
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• 2015

Objectives: The purpose of this study was to determine the best method to analyze PAHs at extremely low concentrations. To this end, 16 PAHswere analyzed simultaneously by GC/MS, HPLC/FLD and HPLC/UVD, and the analytical characteristics of HPLC and GC/MS were compared. Methods: This study was conducted by GC/MS and HPLC/FLD/UVD, and evaluated linearity, precision and detection limit. Standard solutions were prepared for 21 samples in the range of $0.00001{\sim}1.0{\mu}g/mL$ and the samples were divided into four groups. All samples were made in three sets and analysis was replicated seven times. Results: Sixteen PAHs could be simultaneously separated by HPLC and GC/MS, and the adequate equipment was HPLC/FLD. The retention times by HPLC were shorter than GC/MS, and HPLC had better separation for most PAHs than GC/MS. The peaks of naphthalene and naphthalene-D8 partially overlapped for GC/MS. HPLC/FLD had a 20-2000 times lower limit of detection than GC/MS and UVD. However FLD was not adequate for analyzing acenaphthylene because it has too low a fluorescence quantum yield to be detected. The precision of HPLC/FLD/UVD and GC/MS showed less than 20% at $0.001{\mu}g/mL$ PAHs and when the concentration was higher, the coefficient of variation was decreased. HPLC/FLD was better for the overall detection of limits. Conclusions: The results indicate that the HPLC/FLD method has good linear range, precision and a detection of limits from $0.00001{\sim}0.0001{\mu}g/mL$ for all 16 PAHs. This study contributes to providing useful data for analysis technology and can be applied to occupational exposure measurement for PAHs in workplaces.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.321-326
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• 2005

We investigated the effects of pollutants on two pine species (Pinus koraiensis and Pinus rigida) in an industrial region, using a physiological approach. We measured the growth and physiological parameters (photosynthetic activity and chemical contents) of the pine trees in relation to environmental pollutants. The concentrations of manganese (Mn), fluorine (F) and chlorine (CI) in needles of two pine species at the damaged site were significantly higher than those at the control site, and concentrations of essential elements (P) and chlorophyll in needles at the damaged site were significantly lower than at the control site. The light-saturated net photosynthesis $(P_{sat})$, apparent quantum yield $(\Phi)$, carboxylation efficiency (CE) of both pines at the damaged site were significantly lower than those at the control site. The length of shoots and survivorship of needles of two pines at the damaged site were significantly lower than those at the control site. Especially, at damaged site, growth of shoots and needle longevity of P. koraiensis are larger than those of P. rigida.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.677-682
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• 2015

In this paper, we investigated the effect of light on the performance of the receiver system noise and external noise added from the ever-present influence in general optical system. And calculated the reception sensitivity of the receiver at the time of off-keying transmission - from the optical transmission system in consideration of the case that the photo detector has a quantum yield of less than one-one. Not less than 50 it was confirmed that it is possible to configure the low power system is calculated and compared with the case where less than 300 the receiver sensitivity of the optical system to maintain the standard error probability. However, even if these values were considered, and the preamplifier in the receiver, considering a case of using a low-output light source, so that a heavy burden in the value less than the actual system installation, using the light source having less than the output, as shown in Figure 3, the results that were obtained also may be used.

• Journal of Photoscience
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• v.10 no.1
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• pp.9-20
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• 2003

Recent studies on the photoreactivity of l,4-unsaturated systems have changed some ideas that were firmly established in this area of research for many years. Thus, we have described the first examples of 2-aza-di-$\pi$-methane (2-ADPM) rearrangements promoted by triplet-sensitization and by single electron transfer (SET) using electron-acceptor sensitizers. These reactions afford N-vinylaziridine and cyclopropylimine photoproducts in the first examples of di-$\pi$-methane processes that yield three-membered ring heterocycles. l-Aza-1,4-dienes also undergo SET-promoted l-aza-di-$\pi$-methane (l-ADPM) rearrangements via radical-cation intermediates using electron acceptor sensitizers. In some cases, alternative cyclizations yielding different carbocycles and heterocycles have been observed. The l-ADPM and di-$\pi$-methane (DPM) reactions also occur via radical-anion intermediates on irradiation using electron donor sensitizers. On the other hand, the photoreactivity reported for $\beta$,${\gamma}$-unsaturated aldehydes for many years was decarbonylation to the corresponding alkenes. However, our studies demonstrate that these compounds undergo the oxa-di-$\pi$-methane (ODPM) rearrangement with high chemical and quantum efficiency. A comparison of the photochemical reactivity of $\beta$,${\gamma}$-unsaturated aldehydes and corresponding methyl ketones has shown that the ketones do not undergo the ODPM rearrangement while the corresponding aldehydes are reactive by this pathway. Monosubstituted $\beta$,${\gamma}$-unsaturated aldehydes at C-2 undergo the ODPM rearrangement yielding the corresponding cyclopropane carbaldehydes diastereoselectively. Finally, we have described the first examples of reactions, similar to the well know Norrish Type I process, which take place in the triplet excited state of $\beta$,${\gamma}$-unsaturated carbonyl compounds by excitation of the C-C double bond instead of the carbonyl group.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.133-141
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• 1991

The fluorescence characteristics of l-anilinonaphthalene-8-sulfonate (ANS) and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) made the dyes useful probes for the determination of the polarity at the binding sites of several water-soluble polyparacyclophanes. Polyparacyclophanes used were 1,6,20,25-tetraaza[ 6.1.6.1]paracyclophane (CPM 44), 1,7,21,27 -tetraaza[7.1.7.1]paracyclophane (CPM 55). 1,7,21,27 -tetraaza-14,34-dioxa[7.1.7.1]paracyclophane (CPE 55) and 1,8,22,29-tetraaza-15,36-dioxa[8.1.8.1] paracyclophane (CPE 66). The fluorescence quantum yield, emission maximum, and half bandwidth of ANS or TNS obtained in a variety of solvent systems were plotted as a function of four kinds of empirical solvent polarity scales such as dielectric constant (D), (D-l)/(2D+1). Y and Z values. It was found that the Z-value-emission maximum $(\overline}V_F,\;cm^{-1})$ profile showed the most reliable linearity. ANS and TNS interacted with CPM 44, CPM 55, CPE 55. CPE 66. ${\alpha}-cyclodextrin$ (CyD) and ${\beta}-CyD$ in the aqueous solution, and from the emission maxima the polarities (Z-value) of their binding sites were calculated to be 92.65, 87.50, 93.35, 84.52, 94.36, and 90.48 for ANS, respectively. and 91.07, 89.68, 85.44, 86.74 and 87.6 for TNS except for ${\alpha}-CyD$, respectively.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.368-376
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• 2003

The UV-B sensitivity was tested for the intertidal species Chondrus ocellatus from Korea, by measuring photosynthesis estimated as effective quantum yield ($\Phi_{PSII}$) of photosystem II (PS II), growth and content and composition of photosynthetic pigments and UV-absorbing pigments (UVAPs). The $$\Phi_{PSII}$ of the alga decreased with increasing time of exposure to UV-B radiation, followed by fast and nearly full recovery indicating dynamic photoinhibiton. Fresh weight-based growth and pigment contents of C. ocellatus were not seriously affected by UV-B radiation. A single broad peak at 327 nm was obtained from methanol extracts of C. ocellatus, and the absorbance peak increased with increasing UV. The single peak was resolved into three peaks (311, 330 and 336 nm) by the fourth -derivative, and quantitative change in response to UV-B radiation occurred only at 330 nm. High performance liquid chromatography (HPLC) analysis of purified extracts indicated that three MAAs (mycosporine-like amino acids) are present, asterina 330, palythine and shinorine. Field observations during three growing months showed that C. ocellatus exhibit the highest amount of UVAPs in May followed by July and little trace in September, coinciding with the species' phenology. In an ecological context, dynamic photoinhibition as well as accumulation of UVAPs may enable the shallow water red alga C. ocellatus to be well adapted to high UV-B environments.