• Title/Summary/Keyword: $I_c$ degradation

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Dual-Cell Combining Detection Method for Reduction of Residual Frequency Offset Influence on Code Acquisition Systems (나머자 옵셋이 부호획득 시스템에 미치는 영향을 줄이기 위한 듀얼셀 결합 검파 알고리즘)

  • Chong, Da-Hae;Lee, Young-Yoon;Yoon, Tae-Ung;Lee, Young-Po;Lee, Myung-Soo;Yoon, Seok-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.7C
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    • pp.715-723
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    • 2009
  • In this paper, we propose a new detection method called dual-cell combining (DCC) detection for the acquisition in time of spread spectrum codes in the presence of residual frequency offset (RFO). When the RFO exists, the correlation peak used for detection during the acquisition process is split into two neighboring peaks with smaller amplitudes, resulting in considerable degradation in the overall acquisition performance of conventional methods. In the DCC detection method, the decision variable for detection is formed by combining two consecutive correlator outputs so that the influence of the reduction in the correlation peak due to the RFO can be alleviated. Numerical results show that the DCC detection method can offer better mean-time-to-synchrouization performance than the conventional method based on the cell-by-cell detection.

Resveratrol attenuates 4-hydroxy-2-hexenal-induced oxidative stress in mouse cortical collecting duct cells

  • Bae, Eun Hui;Joo, Soo Yeon;Ma, Seong Kwon;Lee, JongUn;Kim, Soo Wan
    • The Korean Journal of Physiology and Pharmacology
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    • v.20 no.3
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    • pp.229-236
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    • 2016
  • Resveratrol (RSV) may provide numerous protective effects against chronic inflammatory diseases. Due to local hypoxia and hypertonicity, the renal medulla is subject to extreme oxidative stress, and aldehyde products formed during lipid peroxidation, such as 4-hydroxy-2-hexenal (HHE), might be responsible for tubular injury. This study aimed at investigating the effects of RSV on renal and its signaling mechanisms. While HHE treatment resulted in decreased expression of Sirt1, AQP2, and nuclear factor erythroid 2-related factor 2 (Nrf2), mouse cortical collecting duct cells (M1) cells treated with HHE exhibited increased activation of p38 MAPK, extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and increased expression of NOX4, $p47^{phox}$, Kelch ECH associating protein 1 (Keap1) and COX2. HHE treatment also induced $NF-{\kappa}B$ activation by promoting $I{\kappa}B-{\alpha}$ degradation. Meanwhile, the observed increases in nuclear $NF-{\kappa}B$, NOX4, $p47^{phox}$, and COX2 expression were attenuated by treatment with Bay 117082, N-acetyl-l-cysteine (NAC), or RSV. Our findings indicate that RSV inhibits the expression of inflammatory proteins and the production of reactive oxygen species in M1 cells by inhibiting $NF-{\kappa}B$ activation.

Cisplatin-induced Alterations of $Na^+$-dependent Phosphate Uptake in Renal Epithelial Cells

  • Lee, Sung-Ju;Kwon, Chae-Hwa;Kim, Yong-Keun
    • The Korean Journal of Physiology and Pharmacology
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    • v.11 no.2
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    • pp.71-77
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    • 2007
  • Cisplatin treatment increases the excretion of inorganic phosphate in vivo. However, the mechanism by which cisplatin reduces phosphate uptake through renal proximal tubular cells has not yet been elucidated. We examined the effect of cisplatin on $Na^+$-dependent phosphate uptake in opossum kidney (OK) cells, an established proximal tubular cell line. Cells were exposed to cisplatin for an appropriate time period and phosphate uptake was measured using $[^{32}P]$-phosphate. Changes in the number of phosphate transporter in membranes were evaluated by kinetic analysis, $[^{14}C]$phosphonoformic acid binding, and Western blot analysis. Cisplatin inhibited phosphate uptake in a time- and dose-dependent manner, and also the $Na^+$-dependent uptake without altering $Na^+$-independent uptake. The cisplatin inhibition was not affected by the hydrogen peroxide scavenger catalase, but completely prevented by the hydroxyl radical scavenger dimethylthiourea. Antioxidants were ineffective in preventing the cisplatin-induced inhibition of phosphate uptake. Kinetic analysis indicated that cisplatin decreased Vmax of $Na^+$-dependent phosphate uptake without any change in the Km value. $Na^+$-dependent phosphonoformic acid binding was decreased by cisplatin treatment. Western blot analysis showed that cisplatin caused degradation of $Na^+$-dependent phosphate transporter protein. Taken together, these data suggest that cisplatin inhibits phosphate transport in renal proximal tubular cells through the reduction in the number of functional phosphate transport units. Such effects of cisplatin are mediated by production of hydroxyl radicals.

Purification and Characterization of Extracellular Aspartic Proteinase of Candida albicans

  • Na, Byoung-Kuk;Lee, Seong-Il;Kim, Sin-Ok;Park, Young-Kil;Bai, Gill-Han;Kim, Sang-Jae;Song, Chul-Yong
    • Journal of Microbiology
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    • v.35 no.2
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    • pp.109-116
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    • 1997
  • An extracellular proteinase of Candida albicans was purified by a combination of 0~75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephacryl S-200 HR molecular sieve chromatography. Its mlecular weight was approximately 41 kDa on SDS-PAGE and isoelectric point was 4.4. The enzyme was inhibited by pepstain A. Optimum enzyme activity ranged from pH 2.0 to 3.5 with its maximum at pH 2.5 and a temperature of 45$^{\circ}C$. The addition of divalent cations, $Ca^{2+}$, Zn$^{2+}$ and $Mg^{2+}$, resulted in no significant inhibition of enzymatic activity. However, some inhibitory effects were observed by Fe$^{2+}$, Ag$^{2+}$ and Cu$^{2+}$. With BSA as substrate, an apparent $K_m$ was determined to be 7$\times$10$^{-7}$ M and $K_i$, using pepstatin A as an inhibitor, was 8.05$\times$10$^{-8}$ M. N-terminal amino acid sequence was QAVPVTLXNEQ. Degradation of BSA and fibronectin was shown but not collagen, hemoglobin, immunoglobulin G, or lysozyme. The enzyme preferred peptides with Glu and Leu at the P$_1$ position, but the enzyme activity was highly reduced when the P$_2$ position was phe or pro. This enzyme showed antigenicity against sera of patients with candidiasis.

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Strategies to Reduce Phytate Content in the Korean Diet

  • Lee, Jee-Min;Li, Sun-Hee;Joung, Hyo-Jee;Paik, Hee-Young
    • International Journal of Human Ecology
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    • v.4 no.1
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    • pp.25-34
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    • 2003
  • High dietary phytate is a known factor in reducing the bioavailability of minerals such as zinc and calcium which are already chronically low in the Korean diet. This study was conducted to develop methods for reducing dietary phytate through the addition of phytate and/or the substitution of high phytate foods with low phytate foods. Ten units of phytase per 100g of uncooked brown rice were added to brown rice gruel resulted in a 16.2% phytate reduction after a 3-hour incubation period; an 18.2% reduction was produced after a 6-hour incubation period. The addition of ten units of phytase per 100g of soybean curd residue at 45$^{\circ}C$, followed by refrigeration for 3 hours, resulted in a 19.1% phytate reduction. The addition of 20 units of phytase under the same conditions reduced phytate content by 24.6%. In this study, two typical Korean meals consisting of legumes and unrefined cereals were prepared as high phytate meals; these were then compared to low phytate meals that had been prepared by treating the foods with phytase and substituting unrefined with refined cereals (i.e., brown rice with white rice, whole wheat bread with white bread). The phytate content of the two high phytate meals was 1878.2mg and 1811.8mg. After the addition of phytase and the food substitution, the phytate content of the low phytate meals was reduced to 788.9mg and 606.0mg. The phytate to zinc molar ratio of high phytate diets was 22.4 and 21.3 and 9.4 and 7.9 for the low phytate meals. These results indicate that the nutritional status of Koreans in terms zinc and other minerals can be improved by phytate reduction. This can be accomplished through the change of milling process for some cereals and/or the enzyme treatment of some high phytate food items.

Characterization of a cysteine proteinase from adult worms of Paragonimus westermani (폐흡충(Parnonimr westemani)성충에서 정제한 cysteine proteinase의 특성)

  • 송철용;김동수
    • Parasites, Hosts and Diseases
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    • v.32 no.4
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    • pp.231-242
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    • 1994
  • Pnragonimus westermnni, the lung fluke, is known to migrate to the pulmonary tissue of mammalian hosts and causes pathological changes in the lungs. An acidic thiol-dependent proteinase with a molecular weight of approximately 20,000 daltons was purified to homogeneity using ion-exchange chromatography and gel filtration chromatography. On SDS-PAGE, the molecular weight of the enzyme was 17,500 daltons. Isoelectric point was 6.45. The enzyme was similar to the acidic cysteine proteinase of vertebrates in the properties of pH optimum, substrate specificity and inhibitor sensitivity. Enzymatic activity was stable at pH 5.5 for at least two days when stored at 4℃. The cysteine proteinase was capable of degrading collagen and hemoglobin. Sera of patients with paragonimiasis and mice infected with R westermani reacted in immunoblots with the partially purified proteinase. This result suggested that the cysteine proteinase of P. westermnni may play a role in migration in tissues, and in acquisition of nutrients by parasites from the host. It is also potentially an antigen for the serodiagnosis of paragonimiasis.

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Mechanism of Action of Nigella sativa on Human Colon Cancer Cells: the Suppression of AP-1 and NF-κB Transcription Factors and the Induction of Cytoprotective Genes

  • Elkady, Ayman I;Hussein, Rania A;El-Assouli, Sufian M
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7943-7957
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    • 2015
  • Background and Aims: Colorectal cancer is one of the leading causes of death in the world. The aim of this study was to investigate the growth-suppression potentiality of a crude saponin extract (CSENS) prepared from medicinal herb, Nigella sativa, on human colon cancer cells, HCT116. Materials and Methods: HCT116 cells were subjected to increasing doses of CSENS for 24, 48 and 72 h, and then harvested and assayed for cell viability by WST-1. Flow cytometry analyses, cell death detection ELISA, fluorescent stains (Hoechst 33342 and acridine orange/ethidium bromide), DNA laddering and comet assays were carried out to confirm the apoptogenic effects of CSENS. Luciferase reporter gene assays, quantitative reverse transcription-polymerase chain reaction and Western blot analyses were performed to assess the impact of CAERS and CFEZO on the expression levels of key regulatory proteins in HCT116 cells. Results: The results demonstrated that CSENS inhibited proliferation and induced apoptosis. Apoptosis was confirmed by flow cytometry analyses, while CSENS-treated cells exhibited morphological hallmarks of apoptosis including cell shrinkage, irregularity in cellular shape, cellular detachment and chromatin condensation. Biochemical signs of apoptosis, such as DNA degradation, were observed by comet assay and gel electrophoresis. The pro-apoptotic effect of CSENS was caspase-3-independent and associated with increase of the Bax/Bcl-2 ratio. CSENS treatment down-regulated transcriptional and DNA-binding activities of NF-${\kappa}B$ and AP-1 proteins, associated with down-regulation of their target oncogenes, c-Myc, cyclin D1 and survivin. On the other hand, CSENS up-regulated transcriptional and DNA-binding activities of Nrf2 and expression of cytoprotective genes. In addition, CSENS modulated the expression levels of ERK1/2 MAPK, p53 and p21. Conclusions: These findings suggest that CSENS may be a valuable agent for treatment of colon cancer.

Molecular dissection of OsSAD1 conferring salt-, ABA- and drought stresses in rice

  • Park, Yong Chan;Jang, Cheol Seong
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.149-149
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    • 2017
  • The RING (Really Interesting New Gene) finger proteins are known to play crucial roles in various abiotic stresses in plants. In this study, we report on RING finger E3 ligase, ${\underline{O}ryza}$ ${\underline{s}ativa}$ ${\underline{s}alt$-, ${\underline{A}BA}$- and ${\underline{d}rounght}$ stress-${\underline{i}nduced}$ RING finger ${\underline{p}}rotein{\underline{1}}$ gene (OsSAD1). In vitro ubiquitination assay demonstrated that unlike OsSAD1, a single amino acid substitution ($OsSAD1^{C168A}$) of the RING domain showed no E3 ligase activity, supporting the notion that the activity of most E3s is specified by a RING domain. Result of Yeast-Two hybridization, In vivo protein degradation assay supports that OsSAD1 interacting with 3 substrate, OsSNAC2, OsGRAS44 and OsPIRIN1, and mediates proteolysis of 3 substrates via the 26S proteasome pathway. Subcellular localizations of OsSAD1 while approximately 62% of transient signals were detected in cytosol, 38% of signals were showed nucleus. However, transiently expression of OsSAD1 was detected in cytosol 30% while as 70% of nucleus under 200 mM salt treated rice protoplasts. Results of bimolecular fluorescence complementation (BiFC) showed that two nucleus-localized proteins (OsSNAC2 and OsGRAS44) interacted with OsSAD1 in the both cytosol and nucleus. Heterogeneous overexpression of OsSAD1 Heterogeneous overexpresssion of OsSAD1 in Arabidopsis exhibited sensitive phenotypes with respect to Salt-, mannitol-responsive seed germination, seedling growth. In ABA conditions, OsSAD1 overexpression plants showed highly tolerance phenotypes, such as root length and stomatal closure. Our findings suggest that the OsSAD1 may play a negative regulator in salt stress response by modulating levels of its target proteins.

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Changes in Serum Metabolites and Growth Characteristics of Korean Native Steers Fed Alcohol-fermented Feeds

  • Lin, G.Z.;Kim, B.W.;Kim, C.H.;Kim, H.S.;Sung, K.I.;Ohh, S.J.;Hong, B.J.;Shin, J.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.5
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    • pp.648-654
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    • 2004
  • This study was carried out to assess whether feeding of alcohol-fermented feeds (AFF) affects the nutritional metabolism and growth characteristics of Korean native steers. Ten steers were randomly assigned to one of two treatment groups. The dietary treatments were AFF (50% commercial beef cattle feed+30% alcohol-fermented soybean curd dregs+20% rice straw) and control (80% commercial beef cattle feed+20% rice straw). The change of serum metabolites and growth characteristics were measured every two months during the whole twelve months experimental period and the relationships between serum metabolites and growth characteristics were simultaneously analyzed. Four hours after feeding AFF, serum alcohol concentration reached its peak with a significantly higher value than that after control feeding (11.9 and 4.9 mg/dl, respectively). Serum glucose and inorganic phosphorus (IP) concentrations (63.1 and 8.4 mg/dl, respectively) of steers fed AFF were higher than those (56.6 and 7.0 mg/dl) fed the control diet. In both treatments, the serum glucose concentration rapidly increased when body weight (BW) of the steer reached about 600kg, while IP concentrations were rapidly diminished at that BW. Lower concentrations of both blood urea nitrogen (BUN) and cholesterol were observed in steers fed AFF up to 450 kg of BW. The IP concentration was correlated with concentrations of BUN, cholesterol and glucose in AFF fed cattle but not in the cattle fed control diets. Average daily gain was higher in steers fed AFF than steers fed control, particularly during the growing stage of cattle. These findings indicated a capability of AFF to improve BW gain of Korean native steers by decreased protein degradation as well as increased fat synthesis.

Effects of Hoesaeng-san Ethanol Extract on the Human Mast cell-mediated Inflammatory Responses (회생산(回生散) 에탄올 추출물이 비만세포 매개성 염증반응에 미치는 영향)

  • Park, Jee Hea;Kwon, Dong Yeol;Lee, Su Kyung
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.28 no.1
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    • pp.45-52
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    • 2014
  • Hoesaeng-san is known to be effective for treating diarrhea and vomiting. However the therapeutic mechanism of Hoesaeng-san is still not well understood. The aim of the present study was to demonstrate the effects of Hoesaeng-san ethanol extract (HSSEE) on the expression of pro-inflammatory cytokines, as well as to elucidate its mechanism of action in the human mast cell line (HMC-1). Mast Cell were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187 in the presence or absence of HSSEE. To study the possible effects of HSSEE, ELISA, RT-PCR, Western blot analysis were used in this study. HSSEE significantly inhibited the PMA plus A23187-induction of inflammatory cytokines such as tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6 and IL-8. In activated HMC-1 cells, phosphorylation of extra-signal response kinase (ERK) 1/2 and c-jun n-terminal kinase (JNK)1/2 decreased after treatment with HSSEE. Moreover HSSEE inhibited PMA plus A23187-induced nuclear factor (NF)-${\kappa}B$ activation and $I{\kappa}B$ degradation. HSSEE suppressed the expression of TNF-${\alpha}$, IL-6, IL-8 through a decrease in the ERK 1/2 and JNK 1/2, as well as activation of NF-${\kappa}B$. These results indicated that HSSEE exerted a regulatory effect on inflammatory reactions mediated by mast cells.