• Title/Summary/Keyword: Fluorescence

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Determination of Polycyclic Aromatic Hydrocarbons in Smoked Food Products (훈연식품 중 polycyclic aromatic hydrocarbons 함량 분석)

  • Seo, Ilwon;Nam, Hejung;Lee, Songyoung;Lee, Kyueun;Shin, Han-Seung
    • Food Engineering Progress
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    • v.13 no.3
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    • pp.195-202
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    • 2009
  • This study was accomplished that analysis of seven polycyclic aromatic hydrocarbons (PAHs) in smoked or nonsmoked processing foods by high performance liquid chromatography (HPLC) with fluorescence detection. The calibration line was constructed with injected different levels of standard concentration. Limit of detection (LOD) and limit of quantification(LOQ) showed higher linearity ($r^{2}$=0.998) reasonably, and recovery exhibited 0.033-0.666 $\mu$g/kg, 0.108-2.217 $\mu$g/kg and 69.31-90.14%, respectively. As a result, the samples using smoked tuna as smoked materials contained seven PAHs with different range from 0.256 to 0.486 $\mu$g/kg. The benzo[a]pyrene, indicator of PAHs, was detected to below the LOQ in two samples. Concentrations of benzo[a]pyrene in three samples were below the 2 $\mu$g/kg which is the limit of regulation. Smoked tuna sauces were detected from 0.321 to 0.552 $\mu$g/kg and not detected in drying powders. PAHs of smoked meat products were ranged from 0.720 to 2.027 $\mu$g/kg and are higher than concentration of tuna smoked samples. PAHs were very low in non-smoked foods including mustard, herb, and roasted meats.

Prelaunch Study of Validation for the Geostationary Ocean Color Imager (GOCI) (정지궤도 해색탑재체(GOCI) 자료 검정을 위한 사전연구)

  • Ryu, Joo-Hyung;Moon, Jeong-Eon;Son, Young-Baek;Cho, Seong-Ick;Min, Jee-Eun;Yang, Chan-Su;Ahn, Yu-Hwan;Shim, Jae-Seol
    • Korean Journal of Remote Sensing
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    • v.26 no.2
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    • pp.251-262
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    • 2010
  • In order to provide quantitative control of the standard products of Geostationary Ocean Color Imager (GOCI), on-board radiometric correction, atmospheric correction, and bio-optical algorithm are obtained continuously by comprehensive and consistent calibration and validation procedures. The calibration/validation for radiometric, atmospheric, and bio-optical data of GOCI uses temperature, salinity, ocean optics, fluorescence, and turbidity data sets from buoy and platform systems, and periodic oceanic environmental data. For calibration and validation of GOCI, we compared radiometric data between in-situ measurement and HyperSAS data installed in the Ieodo ocean research station, and between HyperSAS and SeaWiFS radiance. HyperSAS data were slightly different in in-situ radiance and irradiance, but they did not have spectral shift in absorption bands. Although all radiance bands measured between HyperSAS and SeaWiFS had an average 25% error, the 11% absolute error was relatively lower when atmospheric correction bands were omitted. This error is related to the SeaWiFS standard atmospheric correction process. We have to consider and improve this error rate for calibration and validation of GOCI. A reference target site around Dokdo Island was used for studying calibration and validation of GOCI. In-situ ocean- and bio-optical data were collected during August and October, 2009. Reflectance spectra around Dokdo Island showed optical characteristic of Case-1 Water. Absorption spectra of chlorophyll, suspended matter, and dissolved organic matter also showed their spectral characteristics. MODIS Aqua-derived chlorophyll-a concentration was well correlated with in-situ fluorometer value, which installed in Dokdo buoy. As we strive to solv the problems of radiometric, atmospheric, and bio-optical correction, it is important to be able to progress and improve the future quality of calibration and validation of GOCI.

Element Dispersion and Wallrock Alteration Analysis Using Portable XRF and SWIR in the Samgwang Au Deposit (휴대용 XRF와 단파장적외선 분광분석을 이용한 삼광 금광상의 원소분산 및 모암변질 분석)

  • Kim, Junkyum;Shin, Dongbok;Yoo, Bongchul;Im, Heonkyung;Kim, Ilkyu
    • Economic and Environmental Geology
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    • v.52 no.4
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    • pp.259-274
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    • 2019
  • Using portable XRF and SWIR analyzer, the characteristics of element dispersion and wallrock alterations induced by interaction between hydrothermal fluids and host rocks were investigated and ore exploration factors were estimated for the orogenic-type Samgwang Au deposits. On this purpose, in-situ measurements were conducted for 804 spots at regular intervals with a total of 4,824 times for host rocks, consisting of schist and gneiss, and altered wallrocks contacted with quartz veins in the Bonhang adit of the deposit, and the results were compared with quantitative data obtained by XRF and ICP analysis. The regression coefficients are 0.88 for major elements and 0.56 for trace elements, excluding V. For polished rock slabs, better results came out for major elements, 0.97 and for trace elements, 0.65. In altered wallrocks contacted with quartz veins, elements such as Fe, Zn, and Rb exhibit positive correlations with As in concentrations, while V forms a negative trend. Contour maps demonstrate that As, Zn, Rb, Fe, Ti, Cr, and Ni are enriched together near quartz veins, showing similar elemental behaviors. In-situ analysis using portable SWIR analyzer represents that schist and gneiss contain mica, illite, chlorite, sericite, amphibole, and epidote, while illite, sericite, gypsum, and mica are present in the altered rocks contacted with quartz veins. In contour maps, chlorite occurs mostly in host rocks, while sericite is concentrated near quartz veins. These results are similar to those of previous studies for element dispersion and hydrothermal alteration, and support the possibility for application of in-situ analysis on the exploration of orogenic gold deposit.

Selective Algicidal Effects of a Newly Developed GreenTD against Red Tide Harmful Alga (GreenTD 물질을 이용한 유해 적조 발생 종의 선택적 살조능 평가)

  • Lee, Minji;Shin, Juyong;Kim, Jin Ho;Lim, Young Kyun;Cho, Hoon;Baek, Seung Ho
    • Korean Journal of Environmental Biology
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    • v.36 no.3
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    • pp.359-369
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    • 2018
  • Harmful algal blooms (HABs) are a serious problem for public health and fisheries industries, thus there exists a need to investigate the possible ways for effective control of HABs. In the present study, we investigated the algicidal effects of a newly developed GreenTD against the HABs (Chattonella marina, Heterosigma akashiwo, Cochlodinium polykriokides, and Heterocapsa circularisquama) and non-HABs (Chaetoceros simplex, Skeletonema sp. and Tetraselmis sp.), which is focused on the different population density and concentration gradients of algicidal substances. The time series viability of target alga was assessed based on the activity of Chl. a photosynthetic efficiency in terms of $F_v/F_m$, and in vivo fluorescence (FSU). Effective control of Raphidophyta, C. marina and H. akashiwo was achieved at a GreenTD concentration of $0.5{\mu}gL^{-1}$ and $0.2{\mu}gL^{-1}$, respectively, and regrowth of both the species was not observed even after 14 days. The inhibitory ratio of the dinoflagellate, C. polykriokides was more than 80% at $0.2{\mu}gL^{-1}$ of GreenTD. H. circularisquama was constantly affected in the presence of $0.2{\mu}gL^{-1}$ of GreenTD in the high- and low-population density experimental groups. On the other hand, diatoms, C. simplex, and Skeletonema sp. were not significantly affected even in the presence of $0.2{\mu}gL^{-1}$ of GreenTD and exhibited re-growth activity with the passage of incubation time. In particular, green alga Tetraselmis sp. remained unaffected even in the presence of the highest concentration of GreenTD ($1.0{\mu}gL^{-1}$), implying that non-HABs were not greatly influenced by the algicidal substances. As a result, the algicidal activity of GreenTD on the harmful and nonharmful algae was as follows: raphidophyte>dinoflagellates>diatoms>green alga. Consequently, our results indicate that inoculation of GreenTD substances into natural blooms at a threshold concentration ($0.2{\mu}gL^{-1}$) can maximize the algicidal activity against HABs species. If we consider the dilution and diffusion rate in the field application, it is hypothesized that GreenTD will demonstrate economic efficiency, thus leading to effective control against the target HABs in the closed bay.

The Surface Distribution of Dissolved Gases in the Southwestern East Sea: Comparison of the Primary Production and CO2 Absorption in Summer between Coastal Areas and the Ulleung Basin (동해 남서부해역의 표층 용존 기체 분포: 여름철 연안과 울릉분지의 일차생산력과 CO2 흡수 비교)

  • LEE, INHEE;HAHM, DOSHIK
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.26 no.4
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    • pp.327-342
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    • 2021
  • The global coastal region is considered as a sink for atmospheric CO2. Since most of the studies in the East Sea focused on the Ulleung Basin, the importance of coastal region for carbon cycle has been overlooked. In this study, we compared the biological pump and CO2 absorption between the Ulleung Basin and coastal region by surface measurements of biological O2 supersaturation (𝚫O2/Ar) and partial pressure of CO2 (fCO2). Cold and less saline waters in the coastal regions were in contrast with a warm and saline water in the Ulleung Basin. The coastal waters near Samcheok and Pohang showed higher fluorescence, 𝚫O2/Ar, and lower fCO2 than those in the Ulleung Basin, indicating higher primary production and CO2 absorption in the areas. The average net community production estimated by 𝚫O2/Ar were 19 ± 6 and 60 ± 9 mmol O2 m-2d-1 in the Samcheok and Pohang, respectively, 2-7 times higher than that of 8 ± 4 mmol O2 m-2d-1 in the Ulleung Basin. Similarly, the average CO2 flux between the seawater and atmosphere were -17.1 ± 8.9 and -25.8 ± 13.2 mmol C m-2d-1 in the Samcheok and Pohang, respectively, 4-5 times higher than that of -4.7 ± 2.5 mmol C m-2d-1 in the Ulleung Basin. In the Samcheok and Pohang, degrees of N2 saturation were lower by 3% than that the ambient waters, suggesting the possibility of nitrogen fixation by primary producers.

Development of Method using LC-ESI-MS/MS and KASP for Identification of Gymnema sylvestre in Food (식품에서 당살초 판별을 위한 LC-ESI-MS/MS 분석법과 KASP 마커 개발)

  • Park, Boreum;Lee, Sun Hee;Eom, Kwonyong;Noh, Eunyoung;Moon Han, Kyoung;Hwang, Jinwoo;Kim, Hyungil;Baek, Sun Young
    • Journal of Food Hygiene and Safety
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    • v.37 no.2
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    • pp.46-54
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    • 2022
  • Known for its effectiveness in weight loss and diabetes prevention, Gymnema sylvestre products can be found in the US, Japanese, and Indian markets. However, the recommended dosage or safety of these products has not yet been proven. Therefore, development of an analytical method for detecting the content of Gymnema sylvestre in food products is required. Accordingly, this study proposes an analysis method that can examine Gymnema sylvestre in food using LC-ESI-MS/MS and KASP (Kompetitive Allele-Specific PCR) markers. In LC-ESI-MS/MS, a simultaneous analysis method for gymnemic acid and deacylgymnemic acid was optimized using negative ionization mode, and its validation test was completed for solid and liquid samples. In addition, KASP markers were prepared by finding the specific SNP of G. sylvestre in ITS2 and matK through DNA barcodes. The two KASP markers returned positive FAM fluorescence result when combined with G. sylvestre, and this aspect was confirmed in raw G. sylvestre as well. The applicability of the method was tested on 21 different food and healthy functional products containing G. sylvestre purchased on the internet. As a result, although there was a difference in the ratios of gymnemic acid and deacylgymnemic acid in LC-ESI-MS/MS, the index component was detected in all 21 products samples. In the KASP analysis, 9 products returned positive FAM result, and the rest of the products were found to be containing G. sylvestre extract. This study is the first study to use the dual system of LC-ESI-MS/MS and KASP for the analysis of G. sylvestre. The study has confirmed that these two methods are applicable to the examine G. sylvestre content in food products.

Adsorptive Removal of Radionuclide Cs+ in Water using Acid Active Clay (산활성 점토를 이용한 수중의 방사성 핵종 Cs+ 흡착 제거)

  • Lee, Jae Sung;Kim, Su Jin;Kim, Ye Eun;Kim, Seong Yun;Kim, Eun;Ryoo, Keon Sang
    • Journal of the Korean Chemical Society
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    • v.66 no.2
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    • pp.78-85
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    • 2022
  • Natural white clay was treated with 6 M of H2SO4 and heated at 80℃ for 6 h under mechanical stirring and the resulting acid active clay was used as an adsorbent for the removal of Cs+ in water. The physicochemical changes of natural white clay and acid active clay were observed by X-ray Fluorescence Spectrometry (XRF), BET Surface Area Analyser and Energy Dispersive X-line Spectrometer (EDX). While activating natural white clay with acid, the part of Al2O3, CaO, MgO, SO3 and Fe2O3 was dissolved firstly from the crystal lattice, which bring about the increase in the specific surface area and the pore volume as well as active sites. The specific surface area and the pore volume of acid active clay were roughly twice as high compared with natural white clay. The adsorption of Cs+ on acid active clay was increased rapidly within 1 min and reached equilibrium at 60 min. At 25 mg L- of Cs+ concentration, 96.88% of adsorption capacity was accomplished by acid active clay. The adsorption data of Cs+ were fitted to the adsorption isotherm and kinetic models. It was found that Langmuir isotherm was described well to the adsorption behavior of Cs+ on acid active clay rather than Freundlich isotherm. For adsorption Cs+ on acid active clay, the Langmuir isotherm coefficients, Q, was found to be 10.52 mg g-1. In acid active clay/water system, the pseudo-second-order kinetic model was more suitable for adsorption of Cs+ than the pseudo-first-order kinetic model owing to the higher correlation coefficient R2 and the more proximity value of the experimental value qe,exp and the calculated value qe,cal. The overall results of study showed that acid active clay could be used as an efficient adsorbent for the removal of Cs+ from water.

Photosynthesis, Growth and Yield Characteristics of Peucedanum japonicum T. Grown under Aquaponics in a Plant Factory (식물공장형 아쿠아포닉스에서 산채 갯기름의 광합성, 생육 및 수량 특성)

  • Lee, Hyoun-Jin;Choi, Ki-Young;Chiang, Mae-Hee;Choi, Eun-Young
    • Journal of Bio-Environment Control
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    • v.31 no.1
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    • pp.67-76
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    • 2022
  • This study aimed to determine the photosynthesis and growth characteristics of Peucedanum japonicum T. grown under aquaponics in a plant factory (AP) by comparing those grown under hydroponic cultivation system (HP). The AP system raised 30 fishes at a density of 10.6 kg·m-3 in a 367.5 L tank, and at HP, nutrient solution was controlled with EC 1.3 dS·m-1 and pH 6.5. The pH level ranged from 4.0 to 7.1 for the AP system and 4.0 to 7.4 for the HP system. The pH level in the AP began to decrease with an increase in nitrate nitrogen (NO3-N) and lasted bellower than pH 5.5 for 15-67 DAT. It was found that ammonium nitrogen (NH4-N) continued to increase even under low pH conditions. EC was maintained at 1.3 to 1.5 dS·m-1 in both systems. The concentration of major mineral elements in the fish tank was higher than that of the hydroponics, except for K and Mg. There was no significant difference in the photosynthesis characteristics, but the PIABS parameters were 30.4% lower in the AP compared to the HP at the 34DAT and 12.0% lower at the 74DAT. There was no significant difference in the growth characteristics, but the petiole length was 56% longer in the leaf grown under the AP system. While there was no significant difference in the fresh and dry weights of leaf and root, the leaf area ratio was 36.43% higher in the AP system. All the integrated results suggest that aquaponics is a highly-sustainable farming to safely produce food by recycling agricultural by-products, and to produce Peucedanum japonicum as much as hydroponics under a proper fish density and pH level.

Resveratrol Ameliorates NMDA-induced Mitochondrial Injury by Enhanced Expression of Heme Oxygenase-1 in HT-22 Neuronal Cells (NMDA를 처리한 HT-22 신경세포에서 미토콘드리아 손상을 완화하는 레스베라트롤의 보호 효과와 헴 산화효소-1의 역할)

  • Kang, Jae Hoon;Woo, Jae Suk
    • Journal of Life Science
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    • v.32 no.1
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    • pp.11-22
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    • 2022
  • N-methyl-D-aspartate (NMDA) receptors have received considerable attention regarding their involvement in glutamate-induced neuronal excitotoxicity. Resveratrol has been shown to exhibit neuroprotective effects against this kind of overactivation, but the underlying cellular mechanisms are not yet clearly understood. In this study, HT-22 neuronal cells were treated with NMDA in Mg2+-free buffer and subsequently used as an experimental model of glutamate excitotoxicity to elucidate the mechanisms of resveratrol-induced neuroprotection. We found that NMDA treatment causes a drop in MTT reduction ability, disrupts inside-negative transmembrane potential of mitochondria, depletes cellular ATP levels, and stimulates intracellular ROS production. Double fluorescence imaging studies demonstrated an increased formation of mitochondrial permeability transition (MPT) pores accompanied by apoptotic cell death, while cobalt protoporphyrin and bilirubin showed protective effects against NMDA-induced mitochondrial injury. On the other hand, zinc protoporphyrin IX significantly attenuated the protective effects of resveratrol which was itself shown to enhance heme oxygenase-1 (HO-1) mRNA and protein expression levels. In cells transfected with HO-1 small interfering RNA, resveratrol failed to suppress the NMDA-induced effects on MTT reduction ability and MPT pore formation. The present study suggests that resveratrol may prevent mitochondrial injury in NMDA- treated HT-22 cells and that enhanced expression of HO-1 is involved in the underlying cellular mechanism.

Study on Adsorption of PO43--P in Water using Activated Clay (활성 백토를 이용한 수중의 인산성 인(PO43--P) 흡착에 관한 연구)

  • Hwang, Ji Young;Jin, Ye Ji;Ryoo, Keon Sang
    • Journal of the Korean Chemical Society
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    • v.65 no.3
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    • pp.197-202
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    • 2021
  • In this study, activated clay treated with H2SO4 (20% by weight) and heat at 90 ℃ for 8 h for acid white soil was used as an adsorbent for the removal of PO43--P in water. Prior to the adsorption experiment, the characteristics of activated clay was examined by X-ray Fluorescence Spectrometry (XRF) and BET surface area analyser. The adsorption of PO43--P on activated clay was steeply increased within 0.25 h and reached equilibrium at 4 h. At 5 mg/L of low PO43--P concentration, roughly 98% of adsorption efficiency was accomplished by activated clay. The adsorption data of PO43--P were introduced to the adsorption isotherm and kinetic models. It was seen that both Freundlich and Langmuir isotherms were applied well to describe the adsorption behavior of PO43--P on activated clay. For adsorption PO43--P on activated clay, the Freundlich and Langmuir isotherm coefficients, KF and Q, were found to be 8.3 and 20.0 mg/g, respectively. The pseudo-second-order kinetics model was more suitable for adsorption of PO43--P in water/activated clay system owing to the higher correlation coefficient R2 and the more proximity value of the experimental value qe,exp and the calculated value qe,cal than the pseudo-first-order kinetics model. The results of study indicate that activated clay could be used as an efficient adsorbent for the removal of PO43-P from water.