• Title/Summary/Keyword: Magnesium

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Development of the Simultaneous Analysis of 36 Sulfonylurea Herbicide Residues in Agricultural Products Using LC-MS/MS (LC-MS/MS를 이용한 농산물 중 제초제 Sulfonylurea계 36종 동시 시험법 개발)

  • Su Jung Lee;Jung Mi Lee;Gui Hyun Jang;Hyun-Kyung Kim;Ji Young Kim
    • Korean Journal of Environmental Agriculture
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    • v.42 no.2
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    • pp.139-151
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    • 2023
  • Sulfonylurea herbicides are widely used in agriculture because they have a long residual period and high selectivity. An analytical method was developed using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique for simultaneous determination of sulfonylurea herbicide residues in agricultural products by liquid chromatography tandem mass spectrometry and for establishment MRL (Maximum Residue Limit) of those herbicides in Korea. Extraction was performed using acetonitrile containing 0.1% formic acid with MgSO4 (anhydrous magnesium sulfate) and NaCl (sodium chloride) and the extract was cleaned up using MgSO4 and C18 (octadecyl). The matrix-matched calibration curves were composed of 7 concentration levels from 0.001 to 0.25 mg/kg and their coefficients of determination (R2) exceeded 0.99. The recoveries of three spiking levels (LOQ, 10LOQ, 50LOQ, n=5) were in the range of 71.7-114.9% with relative standard deviations of less than 20.0% for all the five agriculture products. All validation values met criteria of the European Union SANTE/11312/2021 guidelines and Food and Drug Safety Evaluation guidelines. Therefore, the proposed analytical method was accurate, effective, and sensitive for sulfonylurea herbicide residues determination in agricultural commodities.

A study on the preparation and analysis of cordierite by sol-gel method (졸-겔법에 의한 코디어라이트 제조와 분석에 관한 연구)

  • Chun, Kyung Soo;Lee, Young Hwan
    • Analytical Science and Technology
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    • v.21 no.2
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    • pp.123-128
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    • 2008
  • The golden turbid solution of cordierite precursor was obtained by using magnesium ethoxide in sol-gel method, while the clear solution of cordierite precursor was obtained when 5%-$Zr(OC_3H_7)_4$ solution was used in the sol-gel reaction. $SiO_2$ component was confirmed by infrared spectra showing $1045cm^{-1}$ and the stretching vibration of gelish $SiO_4$ showed $1140cm^{-1}$ and $940cm^{-1}$. The component of $Al_2O_3$ showed at $580cm^{-1}$ and network structure of $Al_2O_6$ showed at $680cm^{-1}$. The component of MgO was confirmed at $575cm^{-1}$ as the stretching vibration. X-ray diffraction analysis showed ${\mu}$-cordierite crystal was showed up at temperature above $1000^{\circ}C$ at the mole ratio of cordierite precursor and water (1:5). ${\mu}$-Cordierite and ${\alpha}$-cordierite were coexisted at $1050^{\circ}C$ for the mole ratio of cordierite precursor and ammonia (1:5) while ${\alpha}$-cordierite was only existed at $1100^{\circ}C$ for the same mole ratio as mentioned above.

Changes of Chemical Properties during Liquid Fertilizer Processing using Different Organic materials (유기물을 이용한 액비 제조시 발효액의 화학적 특성 변화)

  • Lee, Guang-Jae;Jeon, Jong-Ok;Park, Jae-Ho;Nam, Sang-Young;Kim, Tae-Jung
    • Journal of the Korean Society of International Agriculture
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    • v.23 no.5
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    • pp.507-512
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    • 2011
  • This study was carried out to investigate the chemical characteristics of different organic liquid fertilizer during fermentation at plastic house in Chungbuk Agricultural Research and Extension Service. Chicken dung, soybean meal, and rice bran were used for nutrient sources. The obtained results from this study were summarized as follows; Total nitrogen contained the highest in soybean meal as 55 mg·kg-1, and phosphate and potassium contained high in chicken dung and rice bran in organic liquid fertilizer materials. The pH of chicken dung was near 7.0, that of soybean meal and rice bran indicated acidity(pH 3.8~4.4). The electrical conductivity of chicken dung consistently increased during fermentation, and that of soybean meal and rice bran increased and decreased early season and increased at late incubation period. Hydrogen sulfide gas occurrence of chicken dung was 3,200 mg·L-1 at early season and 1,600 mg·L-1 at late incubation period, and that of soybean meal and rice bran treatments were not or very low concentration of hydrogen sulfide gas during manufacturing period. The nitrogen and calcium content of organic liquid fertilizer were the higher in chicken dung and soybean meal than rice bran. The phosphate and magnesium content of rice bran was the high as 5.6 g·kg-1 and 1.5 g·kg-1, respectively. There was no difference in potassium content among the different liquid fertilizers during fermentation.

Applications of the Fast Grain Boundary Model to Cosmochemistry (빠른 입계 확산 수치 모델의 우주화학에의 적용)

  • Changkun Park
    • Korean Journal of Mineralogy and Petrology
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    • v.36 no.3
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    • pp.199-212
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    • 2023
  • Diffusion is a powerful tool to understand geological processes recorded in terrestrial rocks as well as extraterrestrial materials. Since the diffusive exchange of elements or isotopes may have occurred differently in the solar nebula (high temperature and rapid cooling) and on the parent bodies (fluid-assisted thermal metamorphism at relatively low temperature), it is particularly important to model elemental or isotopic diffusion profiles within the mineral grains to better understand the evolution of the early solar system. A numerical model with the finite difference method for the fast grain boundary diffusion was established for the exchange of elements or isotopes between constituent minerals in a closed system. The fast grain boundary diffusion numerical model was applied to 1) 26Mg variation in plagioclase of an amoeboid olivine aggregate (AOA) from a CH chondrite and 2) Fe-Mg interdiffusion between chondrules, AOA, and matrix minerals in a CO chondrite. Equilibrium isotopic fractionation and equilibrium partitioning were also included in the numerical model, based on the assumption that equilibrium can be reached at the interfaces of mineral crystals. The numerical model showed that diffusion profiles observed in chondrite samples likely resulted from the diffusive exchange of elements or isotopes between the constituent minerals. This study also showed that the closure temperature is determined not only by the mineral with the slowest diffusivity in the system, but also strongly depends on the constituent mineral abundances.

Sensory and Quality Characteristics of Gambas al Ajillo Retort Foods with Nondigestible Maltodextrin as Functional Labeling Foods (기능성 표시식품형 난소화성말토덱스트린 첨가 감바스 알 아히요(Gambas al ajillo) 레토르트 식품의 관능 및 품질특성)

  • Ji Hoon Park;Yu Ri Choe;Hye Jeong Cho;Jin Kim;Yong Jin Kwon;Jin-Soo Kim;Jung Suck Lee
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.56 no.6
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    • pp.781-789
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    • 2023
  • We investigated the sensory and quality characteristics of gambas al ajillo retort foods with nondigestible maltodextrin (trial gambas) compared with commercially available frozen gambas al ajillo (control). Trial gambas demonstrated approximate compositions of 75.8% moisture, 11.3% protein, 5.8% lipid, 1.7% ash, and 5.4% carbohydrates, indicating lower lipid and carbohydrate contents but higher moisture, protein, and ash levels than that of the control. Sensory assessments conclusively established the superior overall acceptability of trial gambas over the control. Trial gambas exhibited a total amino acid content of 9.62 g/ 100 g, surpassing the 5.39 g of the control. The major amino acids, such as lysine, leucine, arginine, aspartic acid, and glutamic acid, contributed significantly to its enhanced nutritional profile. Mineral analysis revealed higher calcium, phosphorus, magnesium, and iron levels in trial gambas and lower potassium levels than that in the control. Fatty acid profiling identified 18:1n-9 (67.8%) and 16:0 (11.9%) as the predominant fatty acids, in concordance with the control. This study substantiates trial gambas with the health-oriented preferences of the MZ generation while presenting superior sensory and quality attributes compared with the control.

Nutritional Properties of Cookies Made with Israeli Carp Cyprinus carpio (향어(Cyprinus carpio) 함유 쿠키의 영양특성)

  • Ye Youl Kim;Mi-Soon Jang;Jae-Young Oh;Sang In Kang;Sun Young Park;Yu Ri Choe;Ji Hoon Park;Si Hyeong Park;Jin-Soo Kim
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.56 no.6
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    • pp.766-772
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    • 2023
  • This study was conducted to compare the nutritional properties of cookies made with Israeli carp Cyprinus carpio (C-IC) to those made without Israeli carp (control). The proximate composition of C-IC per 100 g was 4.1 g moisture, 9.7 g protein, 29.2 g lipid, 1.4 g ash, and 55.6 g carbohydrates. Moisture, protein and ash contents were significantly higher and the carbohydrate content was significantly lower (P<0.05) in C-IC than control, but there was no difference in lipid content (P>0.05). The total amino acid content of C-IC per 100 g was 9.46 g and the major amino acid was glutamic acid (2.49 g). The mineral contents of C-IC per 100 g were 216.6 mg calcium, 193.2 mg phosphorus, 170.9 mg potassium, and 18.2 mg magnesium, which were all significantly higher than the contents of the control (P<0.05). The major fatty acids of C-IC were 16:0, 18:1n-9, and 18:2n-6. The digestibility of C-IC in the small intestine was 51.3%, which was higher than the digestibility of the control. These results suggest that C-IC have better nutritional properties than the control.

Effect of Mg Addition on the Microstructure and Mechanical Properties of Al-Li-Ce Alloys (Al-Li-Ce계 합금의 미세조직 및 기계적 특성에 미치는 Mg 첨가의 영향)

  • Byeong-Kwon Lee;Eun-Chan Ko;Yong-Ho Kim;Hyo-Sang Yoo;Hyeon-Taek Son;Sung-Kil Hong
    • Korean Journal of Materials Research
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    • v.33 no.10
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    • pp.393-399
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    • 2023
  • In this study, changes in the microstructure and mechanical properties of cast and extruded Al-2Li-1Ce alloy materials were investigated as the Mg content was varied. The density decreased to 2.485, 2.46 and 2.435 g/cm3 when the Mg content in the Al-2Li-1Ce alloy was increased to 2, 4 and 6 wt%, respectively. Intermetallic compounds of Al11Ce3 were observed in all alloys, while the β-phase of Al3Mg2 was observed in alloys containing 6 wt% of Mg. In the extruded material, with increasing Mg content the average grain size decreased to 84.8, 71.6 and 36.2 ㎛, and the fraction of high-angle grain boundaries (greater than 15°) increased to 82.8 %, 88.6 %, and 91.8 %, respectively. This occurred because the increased Mg content promotes dynamic recrystallization during hot extrusion. Tensile test results showed that as the Mg content increased, both the yield strength and tensile strength increased. The yield strength reached 86.1, 107.3, and 186.4 MPa, and the tensile strength reached 215.2, 285, and 360.5 MPa, respectively. However, it is worth noting that the ductility decreased to 27.78 %, 25.65 %, and 20.72 % as the Mg content increased. This reduction in ductility is attributed to the strengthening effect resulting from the increased amount of dissolved Mg, and grain refinement due to dynamic recrystallization.

Analysis of Soil and Leaf Characteristics of Pear Orchards with Lime-Induced Chlorosis Leaves (배나무 엽 황화증상 발생 과원의 토양 및 엽 특성 분석)

  • In Bog Lee;Dae Ho Jung;Pyoung Ho Yi;Seung Tak Jeong;Yoon Kyeong Kim
    • Korean Journal of Environmental Agriculture
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    • v.42 no.4
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    • pp.331-337
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    • 2023
  • Physiological disorders in pear fruit are mainly caused by problems during the growing season, such as lack of calcium in the soil, poor drainage, low porosity, vigorous pruning, and excessive fruiting. In this study, soil physicochemical properties and leaf characteristics were analyzed in pear orchards in four regions of Korea where chlorosis symptoms occurred to determine the causes of chlorosis. The color of chlorotic leaves was diagnosed using the naked eye or SPAD and Hunter values. The soil of the chlorotic orchard had a significantly higher soil pH than that of the regular orchard. Although adequate soil depth was not significantly associated with chlorosis, combined with over-fertilization of the soil with lime, it could potentially impair plant iron uptake. Chlorotic leaves had significantly lower iron and calcium contents and significantly higher magnesium contents than those of regular leaves. Therefore, the intensive occurrence of chlorosis during secondary shoot development around June and July when it is hot and humid may be due to impaired iron and calcium absorption, leading to physiological disorders. To solve this problem, avoiding the over-application of lime and applying foliar fertilizers containing chelated iron is recommended.

Growth environment characteristics of the habitat of Epilobium hirsutum L., a class II endangered wildlife species

  • Kwang Jin Cho;Hyeong Cheol Lee;Sang Uk Han;Hae Seon Shin;Pyoung Beom Kim
    • Journal of Ecology and Environment
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    • v.47 no.4
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    • pp.282-289
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    • 2023
  • Background: As wildlife habitats are being destroyed and growth environments are changing, the survival of animals and plants is under threat. Epilobium hirsutum L., a species that inhabits wetlands, has held legally protected status since 2012. However, no specific measures are currently in place to protect its habitat, leading to a decline in remaining populations as a result of land use change and human activities. Results: The growth environment (including location, climate, land use, soil, and vegetation) of the five habitat sites (Samcheok, Taebaek1, Taebaek2, Cheongsong, Ulleung) of E. hirsutum L. was investigated and analyzed. These habitats were predominantly situated in flat areas with gentle south-facing slopes, at an average altitude of 452.7 m (8-726 m) above sea level in Gangwon-do and Gyeongsangbuk-do. The average annual temperature ranged 11.5℃ (9.2℃-12.9℃), whereas the average annual precipitation ranged 1,304.5 mm (1,062.7-1,590.7 mm). The surrounding land use status was mainly characterized by mountainous areas, and human interference, such as agricultural land and roads, was commonly found in proximity to these natural habitats. Soil physicochemical analysis revealed that the soil was predominantly sandy loam with a slightly high sand content. The average pH measured 7.64, indicating an alkaline environment, and electrical conductivity (EC) averaged 0.33 dS/m. Organic matter (OM) content averaged 66.44 g/kg, available phosphoric acid (P2O5) content averaged 115.73 mg/kg, and cation exchange capacity (CEC) averaged 23.43 cmolc/kg. The exchangeable cations ranged 0.09-0.43 cmol+/kg for potassium (K), 10.23-16.21 cmol+/kg for calcium (Ca), 0.67-4.94 cmol+/kg for magnesium (Mg), and 0.05-0.74 cmol+/kg for sodium (Na). The vegetation type was categorized as E. hirsutum community with high numbers of E. hirsutum L., Persicaria thunbergii (Siebold & Zucc.) H. Gross, Phragmites japonica Steud., Humulus japonicus (Siebold & Zucc.), and Bidens frondosa L.. An ecological flora analysis, including the proportion of lianas, naturalized plants, and annual herbaceous plants, revealed that the native habitat of E. hirsutum L. was ecologically unstable. Conclusions: Analysis of the habitat of E. hirsutum L., a class II endangered wildlife species, provided essential data for local conservation and restoration efforts.

The Behaviors of Phosphorus-32 and Ptoassium-42 under the Control of Thermoperiod and Potassium Level (가리(加里)와 온도주기성(溫度週期性)이 고구마 생육(生育) 및 인(燐)-32, 가리(加里)-42 동태(動態)에 미치는 영향(影響))

  • Kim, Y.C.
    • Korean Journal of Soil Science and Fertilizer
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    • v.1 no.1
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    • pp.89-115
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    • 1968
  • 1. The experiment was carried out for investigating the interaction between potassium nutrition and thermoperiod (as an environment regulating factor) in relation to behaviors of several nutrients including phosphorus-32 and Potassium-42 in IPOMOEA BATAS. 2. To obtain same condition to trace the behaviors of phosphorus and potassum-42 they were simultaneously incorporated to roots. The determination of each CPM by counting twice with adequate interval and calculating true CPM of each isotope according to different half-life, was carried out with satisfactory. 3. Some specific symptoms i.e, chlorosis and withering of growing point under the condition of lower potassium level were found and was accelerated by the low night temperature. 4. A manganese shortage in growing point of the lower potassium level was found by activiation analysis and very low distribution ratio of phosphorus-32 and potassium-42 in the growing point of the lower potassium level was manifested, though the contents of nitrogen, phosphorus, potassium, sodium and magnesium were not in great difference. 5. In addition to the low water content with appearence of "hard", shorterning internode and lower ratio of roots to shoot as well as the symptoms of potassium deficiency such as brown spot in leaf blade and necrosis of leaf margin were appeared at later stage of experiment at the lower potassium level. 6. Very stimulating vegetative growth, e.g, large plant length, leaf expansion, increasing node number and fresh weight as well as high ratio of roots to shoot, high water content was resulted in the condition of higher potassium level. 7. A specific interaction between higher potassium level and thermoperiod was found, that is, the largest tuber production and the largest ratio of roots to shoot were resulted in the combined condition of higher potassium level and constant temperature while the largest plant length, fresh weight etc. i.e. the most stimulative vegetative growth was resulted in the combined condition of higher potassium level and low night temperature. 8. Comparatively low water content in the former condition of stimulative tuber production was resulted(especially at the tuber thickening stage), while high water content in the latter condition of stimulative vegetation was resulted though the higher potassium level made generally high water contents. 9. The nitrogen contents of soluble and insoluble did not make distinct difference between the lower and higher potassium level. 10. Though the phosphorus contents were not distinctly different by the potassium level, the lower potassium level made the percentage of phosphorus increased at tuber forming stage accumulating more phosphorus in roots, while the higher potassium level decreased percentage of phosphorus at that stage. 11. The higher potassium level made distinctly high potassium contents than the lower potassium level and increased contents at the tuber forming stage through both conditions. 12. The sodium contents were low in the condition of higher potassium level than the lower potassium level and decreased at tuber forming stage in both conditions, on the contary of potassium. 13. Except the noticeable deficeney of manganese in the growing point of the lower potassium level, mangense and magnesium contents in other organs did not make distinct difference according to the potassium level. 14. Generally more uptake and large absorption rate of phosphorus-32 and potassium-42 were resulted at the higher potassium level, and the most uptake, and the largest absorption rate of phosphorus and potassium-42 (especially potassium-42 at tuber forming stage) were resulted in the condition of higher potassium level and constant temperature which made the highest tuber production. 15. The higher potassium level stimulated the translocation of phoshorus-32 and potassium-42 from roots to shoots while the lower potassium level suppressed or blocked the translocation. 16. Therefore, very large distribution rate of $p^{32}$, $K^{42}$ in shoot, especially, in growing point, compared with roots was resulted in the higher potassium level. 17. The lower potassium level suppressed the translocation of phosporus-32 from roots to shoot more than that of potassium-42. 18. The uptake of potassium-42 and translocation in IPOMOEA BATATAS were more vivid than phosphorus-32. 19. A specific interaction between potassium nutrition and thermoperiod which resulted the largest tuber production etc. was discussed in relation to behaviors of minerals and potasium-42 etc. 20. Also, the specific effect of the lower and higher potassium level on the growth pattern of IPOMOEA BATATAS were discussed in relation to behaviors of minerals and isotopes. 21. An emphasize on the significance of the higher potassium level as well as the interaction with the regulating factor and problem of potassium level (gradient) for crops product ion were discussed from the point of dynamical and variable function of potassium.

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