• Title/Summary/Keyword: ${GC}^2$

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Facile Preparation of Biodegradable Glycol Chitosan Hydrogels Using Divinyladipate as a Crosslinker

  • Kim, Beob-Soo;Yeo, Tae-Yun;Yun, Yeon-Hee;Lee, Byung-Kook;Cho, Yong-Woo;Han, Sung-Soo
    • Macromolecular Research
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    • v.17 no.10
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    • pp.734-738
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    • 2009
  • Biodegradable, pH-sensitive, glycol chitosan (GC) hydrogels were prepared using divinyl adipate (DVA) as a crosslinker and acetic acid as a catalyst. DVA has highly reactive double vinyl ester groups and GC contains a high density of hydroxyl groups, with two in every glucosamine unit. The transesterification reaction between vinyl esters and hydroxyl groups produced crosslinked GC hydrogels. The initial crosslinking reaction was monitored by measuring the viscosity of the reaction mixture. When DVA was added to the GC solution and heated to $50^{\circ}C$, the viscosity of the GC solution gradually increased, implying a crosslinking reaction and hydrogel formation. A new peak from the ester group was observed in the FTIR spectra of the GC hydrogels, confirming the crosslinking reaction. The synthesized GC hydrogel showed pH-dependent water absorbency, mainly due to the presence of amine groups ($-NH_2$) at the C-2 position of the glucosamine unit of GC. The water absorbency greatly increased at acidic pH and slightly decreased at alkaline pH. The GC hydrogel gradually degraded in $37^{\circ}C$ water due to hydrolysis of the ester bonds, which were intermolecular crosslinking sites. A red dye, 5-carboxyltetramethyl-rhodamine (CTMR), was entrapped in the GC hydrogels as a model compound. CTMR was released from GC hydrogels in two steps: an initial burst release mainly due to desorption and diffusion, and a second sustained release possibly due to gradual degradation.

Identification of Volatile Flavor Components of Chinese chive and Baek-Seok Chie (중국 부추와 백석 부추의 휘발성 풍미 성분의 동정)

  • 이혜정;박희옥
    • The Korean Journal of Food And Nutrition
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    • v.10 no.4
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    • pp.539-543
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    • 1997
  • This study was carried out to investigate the Chinese and Baek-Seok chive. We collect the volatile components of Chinese and Baek-Seok chive by dynamic head space method. Chinese chive was analyzed by Gas chromatography-Mass Spectrometry(GC-MS). 28 components including 20 sulfides, 5 alcohols, 1 benzene and 2 aldehydes compounds were identified in samples, Also Baek-Seok chive was analyzed by GC-MS. 32 components including 19 sulfides, 10 alcohols, 2 benzonoides and 1 aldehyde compounds were confirmed.

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A Study on the Analysis of Pesticide Residue in Banana by GC/MSD (GC/MSD를 이용한 바나나 중에서의 잔류농약 분석법에 관한 연구)

  • 박성수;김동원
    • The Korean Journal of Food And Nutrition
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    • v.9 no.2
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    • pp.217-222
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    • 1996
  • We studied about analyzing carbamate pesticides, organochlorine, organophosphorus pesticides simultaneously using by GC/MSD. For this, instead of HPLC which is generally used in analyzing carbamate pesticides, GC was used and all hydrogen of -NH group in carbamate pesticides were substituted for trifluoroacetyl group which is stable at heat And eight pesticide resdidues were not detected in nine samples circulated in the city.

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The Aroma Components of Commercial Green Tea Picked in August (수확시기가 늦은 시판녹차의 향기성분)

  • Choi, Sung-Hee
    • Journal of Life Science
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    • v.5 no.2
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    • pp.20-20
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    • 1995
  • The aroma components of commercial green teas picked inAugust were collected and identified. The extract of aroma compounds in green tea were accoimplished by a modified rotary evaporation. The concentrated wxtracts were analyzed and identified by GC and GC-MS. In GC analysis, T$_{R}$ value of GC represented bt KI value which standardized. The most abundant components of green teas picked in August were 1-Penten-3-ol, trans, trans-2, 4-heptadienal, linalool, $\beta$-ionone and nerolidol.

The Aroma Components of Commercial Green Tea Picked in August (수확시기가 늦은 시판녹차의 향기성분)

  • 최성희
    • Journal of Life Science
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    • v.5 no.2
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    • pp.76-80
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    • 1995
  • The aroma components of commercial green teas picked inAugust were collected and identified. The extract of aroma compounds in green tea were accoimplished by a modified rotary evaporation. The concentrated wxtracts were analyzed and identified by GC and GC-MS. In GC analysis, T$_{R}$ value of GC represented bt KI value which standardized. The most abundant components of green teas picked in August were 1-Penten-3-ol, trans, trans-2, 4-heptadienal, linalool, $\beta$-ionone and nerolidol.

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Influence of Dietary Supplemental Germanium Colloid on Egg -Quality and Immune Response in Layers (산란계 사료에 게르마늄의 첨가가 계란품질 및 면역반응에 미치는 영향)

  • 홍종욱;김인호;권오석;이상환;민병준;이원백
    • Korean Journal of Poultry Science
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    • v.29 no.1
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    • pp.7-12
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    • 2002
  • This study was conducted to investigate the effects of feeding germanium colloid(GC) on the egg quality and immune response in 1aying hens. One hundred forty four layers, 32-wk-old ISA Brown, were used in a 40-d experimental assay with a 7-d adjustment Period. Dietary treatments included 1) control (basal diet; CON), 2) 0.5ppm GC (basal diet + 0.Sppm germanium), 3) 1.0ppm GC (basal diet + 1.0 ppm germanium) . For overall Period, hen-day e99 Production tended to be increased as the concentration of GC in the diets was increased with significant difference (linear effect, p<0.01) . Laying hens fed 0.5ppm GC diet were significantly (P<0.01) lower in egg shell breaking strength than laying hens fed CON or 1.0 ppm GC diets. Egg shell thickness and yolk color were not influenced by GC supplementation. Laying hens fed 1.0ppm GC diet were h19her in egg yolk Index than laying hens fed CON and 0.5ppm GC diets with significant difference (quadratic effect, p<0.02) . As adding level of germanium colloid increased in the diets, the total serum cholesterol and triglyceride tended to be decreased. However, the effect of GC supplementation did not show significant in the levers of total serum cholesterol and triglyceride. Also, HDL- and LDL+VLDL-cholesterol in serum were not statistically different among the treatments. Red blood cell and white blood cell count in blood tended to be increased as the concentration of GC in the diets was increased with significant difference (P<0.01) . Hematocrit concentration in blood was successfully Increased by supplementation of GC (P<0.01) . In conclusion, although egg quality was not influenced by GC supplementation, supplementing GC Improved Immune status in laying hens.

Assessment of MJO Simulation with Global Coupled Model 2 and 3.1 (Global Coupled 모델 2와 3.1의 MJO 모의성능 평가)

  • Moon, Ja-Yeon;Kim, Ki-Young;Cho, Jeong-A;Yang, Young-Min;Hyun, Yu-Kyung;Kim, Baek-Jo
    • Atmosphere
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    • v.32 no.3
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    • pp.235-246
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    • 2022
  • A large number of MJO skill metrics and process-oriented MJO simulation metrics have been developed by previous studies including the MJO Working Group and Task Force. To assess models' successes and shortcomings in the MJO simulation, a standardized set of diagnostics with the additional set of dynamics-oriented diagnostics are applied. The Global Coupled (GC) model developed for the operation of the climate prediction system is used with the comparison between the GC2 and GC3.1. Two GC models successfully capture three-dimensional dynamic and thermodynamic structure as well as coherent eastward propagation from the reference regions of the Indian Ocean and the western Pacific. The low-level moisture convergence (LLMC) ahead of the MJO deep convection, the low-level westerly and easterly associated with the coupled Rossby-Kelvin wave and the upper-level divergence are simulated successfully. The GC3.1 model simulates a better three-dimensional structure of MJO and thus reproduces more realistic eastward propagation. In GC2, the MJO convection following the LLMC near and east of the Maritime Continent is much weaker than observation and has an asymmetric distribution of both low and upper-level circulation anomalies. The common shortcomings of GC2 and GC3.1 are revealed in the shorter MJO periods and relatively weak LLMC as well as convective activity over the western Indian Ocean.

CircCOL1A2 Sponges MiR-1286 to Promote Cell Invasion and Migration of Gastric Cancer by Elevating Expression of USP10 to Downregulate RFC2 Ubiquitination Level

  • Li, Hang;Chai, Lixin;Ding, Zujun;He, Huabo
    • Journal of Microbiology and Biotechnology
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    • v.32 no.7
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    • pp.938-948
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    • 2022
  • Gastric cancers (GC) are generally malignant tumors, occurring with high incidence and threatening public health around the world. Circular RNAs (circRNAs) play crucial roles in modulating various cancers, including GC. However, the functions of circRNAs and their regulatory mechanism in colorectal cancer (CRC) remain largely unknown. This study focuses on both the role of circCOL1A2 in CRC progression as well as its downstream molecular mechanism. Quantitative polymerase chain reaction (qPCR) and western blot were adopted for gene expression analysis. Functional experiments were performed to study the biological functions. Fluorescence in situ hybridization (FISH) and subcellular fraction assays were employed to detect the subcellular distribution. Luciferase reporter, RNA-binding protein immunoprecipitation (RIP), co-immunoprecipitation (Co-IP), RNA pull-down, and immunofluorescence (IF) and immunoprecipitation (IP) assays were used to explore the underlying mechanisms. Our results found circCOL1A2 to be not only upregulated in GC cells, but that it also propels the migration and invasion of GC cells. CircCOL1A2 functions as a competing endogenous RNA (ceRNA) by sequestering microRNA-1286 (miR-1286) to modulate ubiquitin-specific peptidase 10 (USP10), which in turn spurs the migration and invasion of GC cells by regulating RFC2. In sum, CircCOL1A2 sponges miR-1286 to promote cell invasion and migration of GC by elevating the expression of USP10 to downregulate the level of RFC2 ubiquitination. Our study offers a potential novel target for the early diagnosis and treatment of GC.

The Expression of Apoptosis Related Genes bcl-2, TRPM-2 in Luteinized Human Granulosa Cells (황체화된 인간 과립세포에서 Apoptosis 관련 유전자인 bcl-2와 TRPM-2의 발현)

  • Lee, B.S.;Choi, E.A.;Chang, K.H.;Kim, J.Y.;Bae, S.W.;Park, K.H.;Cho, D.J.;Lee, K.;Kim, J.W.;Song, C.H.
    • Clinical and Experimental Reproductive Medicine
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    • v.24 no.2
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    • pp.267-271
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    • 1997
  • Apoptosis, programmed cell death, is posulated to occur in granulosa cells in ovarian follicular atresia. bcl-2 gene serves as protector from apoptosis and, thus, is associated with increased cell survival. TRPM-2 gene expression has been implicated as a trigger of apoptosis in rat prostate, uterus and mammary gland. Our objective was to determine if bcl-2 and TRPM-2 are expressed in luteinized human GC and, therefore, have regulatory functions for apoptosis in GC. Human GC were obtained via oocyte retrival from the infertile patients stimulated with exogeneous gonadotropins while undergoing IVF. GC were isolated from follicular fluid using Percoll gradient centrifugation. The GC were further purified with anti-CD45 magnetic beads to remove contaminating WBC's. RT-PCR were performed to analyze the mRNA expression of bcl-2 and TRPM-2 in the GC. The PCR primers were designed to amplify a 195 bp fragment of bcl-2 and a 174 bp fragment of TRPM-2. The PCR products were electrophoresed on 4% agarose gel. Three separate experiments indicated that both bcl-2 and TRPM-2 are concurrently expressed in human GC. We cultured granulosa cells with FSH (1 ng/ml) for 1 day to investigate the relative changes of TRPM-2 mRNA level with RNAse protection assay. When we cultured GC with serum free medium for 1 day TRPM-2 mRNA level increased with 1.3 fold, however it was decreased 0.64 fold with FSH. Therefore we conclude that bcl-2 and TRPM-2 are concurrently expressed and that the interaction of their products may be involved in GC apoptosis. And TRPM-2 may be regulated with FSH.

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Study on Fishy Off-flavor in Porcine Liver by GC-O (GC-olfactometry를 이용한 돼지간의 비린내불쾌취 성분 연구)

  • Im, Sung-Im;Choi, Sung-Hee
    • Korean Journal of Food Science and Technology
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    • v.35 no.3
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    • pp.353-358
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    • 2003
  • Volatile compounds of porcine liver were collected by simultaneous steam distillation and extraction and steam distillation under reduced pressure. Volatiles were analyzed by gas chromatography (GC) and GC-mass spectrometry. Key aroma compounds of off-flavor in porcine liver were characterized using GC-olfactometry technique. Concentrates of cooked porcine liver had odor of a typical liver, fishy, and metallic off-flavor. Aroma concentrates showed over 90 peaks, of which 69 compounds were positively and/or tentatively identified. 1-Octen-3-one, 1-hexanol, (E)-2-nonenal, (Z)-4-decenal, (E,E)-2,4-heptadienal and (E,E)-2,4-decadienal were newly identified in this study. These compounds seem to be produced from unsaturated fatty acids of porcine liver by oxidation. 1-Octen-3-one (metallic), 1-hexanol (metallic) and (E,E)-2,4-heptadienal(fishy) have been implicated in fishy and metallic off-flavor in cooked porcine liver.