• 한국세라믹학회지
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• 제52권6호
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• pp.473-478
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• 2015

Green bodies of earthenware tile were prepared from a mixture of earthenware tile powder and SiC as forming agents by applying a conventional process. Granule powder for tile samples was prepared using the spray drying method with commercial earthenware raw material with a quantity of SiC of 0.3 wt%. The applied pressure was $250kg{\cdot}f/m^2$ and the firing temperature was $1050-1200^{\circ}C$. The effects of the SiC particle size and sintering temperature on the open porosity and total porosity were investigated and the correlative mechanism was also discussed. While total porosity was not significantly changed by decreasing the SiC particle size, the open porosity showed a gradual decrease, which represents an increase of the closed porosity. As the sintering temperature increased, coarsening was made among the pores due to excessive oxidation. The volume shrinkage and bending strength were demonstrated for the sintered tile samples. The sintered bulk density was also measured to determine the weight reduction value.

• 한국화재소방학회논문지
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• 제23권3호
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• pp.61-66
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• 2009

본 연구에서는 미분무수 노즐을 이용하여 설치높이 변화에 따른 3종의 포 소화 약제를 각각 혼합하여 소화성능 실험을 수행하였다. 소화성능 실험 결과 순수한 물과 기존의 3%형 수성막포를 사용한 경우보다는 2%형 미분무수 전용 수성막포와 1%형 합성계면활성제포가 더욱 빠른 소화시간을 나타내었다. 또한, 순수한 물만을 사용한 경우에는 3.5m, 포 소화 약제를 사용하였을 때에는 4m의 설치높이에서 가장 좋은 소화효과 나타내었다.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.429-438
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• 2020

The emergence of multi-drug resistant, pathogenic methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health and has created a need for novel functional therapeutic agents. In this study, we evaluated the underlying mechanisms of the anti-MRSA effect of an azaphilone pigment, sclerotiorin (SCL) from Penicillium sclerotiorum. The antimicrobial activity of SCL was evaluated using agar disc diffusion, broth microdilution, time-kill assays and biophysical studies. SCL exhibits selective activity against Gram positive bacteria including MRSA (range, MIC = 128-1028 ㎍/ml) and exhibited rapid bactericidal action against MRSA with a > 4 log reduction in colony forming units within three hours of administration. Biophysical studies, using fluorescent probes and laser or electron microscopy, demonstrated a SCL dose-dependent alternation in membrane potential (62.6 ± 5.0.4% inhibition) and integrity (> 95 ± 2.3%), and the release of UV260 absorbing materials within 60 min (up to 3.2 fold increase, p < 0.01) of exposure. Further, SCL localized to the cytoplasm and hydrolyzed plasmid DNA. While in vitro checkerboard studies revealed that SCL potentiated the antimicrobial activity of topical antimicrobials such as polymixin, neomycin, and bacitracin (Fractional Inhibitory Concentration Index range, 0.26-0.37). Taken together these results suggest that SCL targets the membrane and DNA of MRSA to facilitate its anti-MRSA antimicrobial effect.

• 한국식품저장유통학회지
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• 제12권3호
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• pp.247-251
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• 2005

아가리쿠스버섯의 약효성분으로 고형 음용차를 제조하기 위하여 건 버섯을 열수추출, 에탄올 침전, 투석, 동결건조 등의 처리를 행하여 단백다당체를 분리하고 부형제로 dextrin(DE=9, DE=23) 및 ${\beta}$-cyclodextrin(CD)을 각각 첨가하여 분무건조한 후 압출하여 과립을 제조한 다음 부형제의 종류에 따른 과립의 품질특성을 조사 비교하였다. 과립의 수분함량은 DE=9 첨가구에서 가장 높았고, 총당 함량은 ${\beta}$-CD, DE=23, DE=9 첨가구 순이었으나, pH와 단백질함량은 부형제에 따른 유의적인 차이를 보이지 않았다. L값은 DE=9, ${\beta}$-CD, DE=23 첨가구 순이었고, -a값은 부형제간 거의 차이가 없었으며, b값은 ${\beta}$-CD 첨가구에서 가장 높게 나타났다. 과립의 용해도는 DE=9보다 DE=23과 ${\beta}$-CD 첨가구에서 높았으며 두 종류의 부형제간 차이는 보이지 않았다. 흡습성은 ${\beta}$-CD 첨가구에서 가장 크게 나타났으며 DE=9 첨가구에서 가장 적게 나타났다. 관능검사 결과 종합적인 기호도는 ${\beta}$-CD가 가장 우수하였다.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.161-166
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• 2013

At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer's disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman's reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor ($IC_{50}$ = 27.1 ${\mu}g/ml$) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and $^1H$- and $^{13}C$-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the $H_2O_2$- and ${\beta}$-amyloid-injured PC12 cells at 1 to 25 ${\mu}g/ml$. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8177-8186
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• 2016

The present study was aimed at determining the effects of alkylating and oxidative stress inducing agents on a newly identified variant of DNA polymerase beta ($pol{\beta}{\Delta}_{208-304}$) specific for ovarian cancer. $Pol{\beta}{\Delta}_{208-304}$ has a deletion of exons 11-13 which lie in the catalytic part of enzyme. We compared the effect of these chemicals on HeLa cells and HeLa cells stably transfected with this variant cloned into in pcDNAI/neo vector by MTT, colony forming and apoptosis assays. $Pol{\beta}{\Delta}_{208-304}$ cells exhibited greater sensitivity to an alkylating agent and less sensitivity towards $H_2O_2$ and UV when compared with HeLa cells alone. It has been shown that cell death in $Pol{\beta}{\Delta}_{208-304}$ transfected HeLa cells is mediated by the caspase 9 cascade. Exon 11 has nucleotidyl selection activity, while exons 12 and 13 have dNTP selection activity. Hence deletion of this part may affect polymerizing activity although single strand binding and double strand binding activity may remain same. The lack of this part may adversely affect catalytic activity of DNA polymerase beta so that the variant may act as a dominant negative mutant. This would represent clinical significance if translated into a clinical setting because resistance to radiation or chemotherapy during the relapse of the disease could be potentially overcome by this approach.

• 한국임상약학회지
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• 제31권1호
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• pp.21-26
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• 2021

Background: Pharmacogenomics is the study of how genetic mutations in patients affect their response to drugs. Pharmacogenomic studies aim to maximize drug effects and minimize adverse drug events. The Food and Drug Administration and the European Medicine Agency published guidelines for pharmacogenetics in 2005 and 2006, respectively; the Korean Ministry of Food and Drug Safety followed suit in 2015. Methods: This study analyzed pharmacogenomic information in the Korean Ministry of Food and Drug Safety's integrated drug information system to evaluate whether domestic pharmaceutical products reflect the current research on pharmacogenomic differences. Results: In June 2020, the Korean pharmacogenomic database contained genomic data on 90 compounds. Of these, 45 compounds were classified as "Antineoplastic and immunomodulating agents." The other 45 non-antineoplastic agents were in the following categories: Anti-infectives, Mental & behavior disorder, Hormone & metabolism related diseases, Cardiovascular system, Skin & subcutaneous tissue disease, Genito-urinary system and sex hormones, Blood and blood forming organs, Nervous system, Alimentary tract and metabolism, Musculo-skeletal system, and Other conditions including the respiratory system. In addition, 30 additives unrelated to the main ingredient were associated with genetic precautions. Conclusion: This study showed that antineoplastic and immunomodulating agents accounted for half the drugs associated with pharmacogenetic information. For antitumor and immunomodulatory drugs, genomic tests were recommended depending on the indication; this was in contrast to genomic testing recommendations for non-antineoplastic medications. Genomic tests were rarely requested or recommended for non-antineoplastic medications because the relationships between genotype and efficacy among those drugs were relatively weak.

• 대한의생명과학회지
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• 제18권3호
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• pp.313-318
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• 2012

Acanthamoeba is an opportunistic pathogen known to cause granulomatous amoebic encephalitis and amebic keratitis. Acanthamoeba exhibits life cycle consisting of trophozoite and cyst, and the cyst is highly resistant to variable antibiotics and therapeutic agents. To understand the encystation mechanism of Acanthamoeba, the expression profiles of trophozoite and cyst were compared by gene ontology (GO) analysis. Ribosomal proteins and cytoskeletal proteins were highly expressed in trophozoite. In cyst, various protease, and signal transduction - and protein turnover - related proteins were highly expressed. These results correlated with eukaryotic orthologous groups (KOG) assignment and microarray analysis of Acanthamoeba trophozoite and cyst ESTs. The information of differential expression profiles of trophozoite and cyst would provide important clues for research on encystation mechanism of cyst forming protozoa including Acanthamoeba.

• Toxicological Research
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• 제34권4호
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• pp.297-302
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• 2018

Cells are constantly exposed to endogenous and exogenous chemical and physical agents that damage their genome by forming DNA lesions. These lesions interfere with the normal functions of DNA such as transcription and replication, and need to be either repaired or tolerated. DNA lesions are accurately removed via various repair pathways. In contrast, tolerance mechanisms do not remove lesions but only allow replication to proceed despite the presence of unrepaired lesions. Cells possess two major tolerance strategies, namely translesion synthesis (TLS), which is an error-prone strategy and an accurate strategy based on homologous recombination (homology-dependent gap repair [HDGR]). Thus, the mutation frequency reflects the relative extent to which the two tolerance pathways operate in vivo. In the present paper, we review the present understanding of the mechanisms of TLS and HDGR and propose a novel and comprehensive view of the way both strategies interact and are regulated in vivo.

• Journal of Plant Biology
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• 제32권4호
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• pp.343-350
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• 1989

Calcium promoted ethylene production from mungbean hypocotyl segments incubated in the presence of either auxin or cytokinin (kinetin). Time course studies indicated that the calcium effect on ethylene production had a longer latent period (about 6 h) in combination with kinetin than with auxin. Studies on the effects of agents that are known to interfere with either action or transport (uptake) of calcium on ethylene biosynthesis indicated different patterns between auxin- and kinetin-treated tissues. Auxin-induced ethylene production was inhibited by the calmodulin inhibitor, trifluoperazine (TFP), and this inhibition was overcome by high concentrations of calcium applied, but TFP had no significant effect on kinetin-induced ethylene production regardless of calcium in the medium. The calcium channel blocker, verapamil, inhibited auxin-induced, but had little effect on kinetin-induced, ethylene producton. In vivo activity of "ethylene forming enzyme (EFE)" was found to be substantially promoted by calcium treatment. The enzyme activity was further increased by kinetin when segments were simultaneously treated with calcium, but auxin did not have such an effect.an effect.