• Archives of Pharmacal Research
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• v.19 no.1
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• pp.1-5
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• 1996

Laminated films composed of drug-containing reservoir layer and drug-free membrane were prepared. Zero-order drug release with lag time was achieved by laminating drug-free film onto the reservoir layer, while burst effect was observed on cast-on film. The rate controlling membrane was either attached to or cast directly into the reservoir. The release rate was independent on the reservoir composition but dependent on the composition of rate-controlling membrane. In growth inhibitory test of cephalexin from Eudragit RS film to Streptococcus Mutans, the disk even after release test for 72 hours showed more bacterial growth inhibition than that of control. Permeation of drug through rat skin was proportional to the HPC fraction in the film. We could control the release of cephalexin from the film by changing the fraction of Eudragit RS, HPC and DEP content. Consequently, Eudragit RS/HPC film was found to be very effective system for local delivery of drugs.

• Transactions on Electrical and Electronic Materials
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• v.8 no.1
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• pp.5-10
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• 2007

Using a reference slurry, ammonium dodecyl sulfate (ADS), an anionic and environmentally friendly surfactant, was investigated as an alternative to BTA for its inhibition and lubrication characteristics. Results demonstrated that the inhibition efficiency of ADS was superior to that of BTA. Coefficient of friction (COF) was the lowest when the slurry contained ADS. This suggested that adsorbed ADS on the surface provided lubricating action thereby reducing the wear between the contacting surfaces. Temperature results were consistent with the COF and removal rate data. ADS showed the lowest temperature rise again confirming the softening effect of the adsorbed surfactant layer and less energy dissipation due to friction. Spectral analysis of shear force showed that increasing the pad-wafer sliding velocity at constant wafer pressure shifted the high frequency spectral peaks to lower frequencies while increasing the variance of the frictional force. Addition of ADS reduced the fluctuating component of the shear force and the extent of the pre-existing stick-slip phenomena caused by the kinematics of the process and collision event between pad asperities with the wafer. By contrast, in the case of BTA, there were no such observed benefits but instead undesirable effects were seen at some polishing conditions. This work underscored the importance of real-time force spectroscopy in elucidating the adsorption, lubrication and inhibition of additives in slurries in CMP.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.1
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• pp.7-12
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• 2008

To develop a whitening agent, cytotoxicity of the soluble collagen isolated from Todarodes pacificus (CIT) was evaluated. CIT tested for cytotoxicity on human dermal fibroblast (CCD-986sk) was exhibited very low cytotoxicity. Because tyrosinase is the key enzyme for melanin biosynthesis, the use of various tyrosinase inhibitors is a common practice for whitening purpose in cosmetics. Tyrosinase inhibitory activity and melanin production assay were measured to confirm the whitening effect. The inhibitory effect of MMP-1 in UV-irradiated human dermal fibroblast was also performed. CIT showed strong inhibition potency on tyrosinase by 51.5% at 0.2 mg/mL which increased the inhibition by increasing the concentration of CIT, and showed 69.1% inhibition at 1.0 mg/mL. CIT showed strong inhibition effect on melanin production with 82% at 1.0 mg/mL. The CIT also reduced about 76% expression of MMP-1 in UV-irradiated CCD-986sk cell at 1.0 mg/mL. From the preliminary observations, we suggest that the collagen isolated from CIT could be a potential source of natural skin-whitening and anti-aging agents for the photo-damaged skin.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.267-270
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• 2003

We have studied the interfacial diffusion phenomena and the role of ${\alpha}-Al_2O_3$ buffer layer as a diffusion barrier in the $Ba-ferrite/SiO_2$ magnetic thin films for high-density recording media. In the interface of amorphous Ba-ferrite ($1900-{\AA}-thick)/SiO_2$ thin film during annealing, the interfacial diffusion started to occur at ${\sim}700^{\circ}C$. As the annealing temperature increased up to $800^{\circ}C$, the interfacial diffusion abruptly proceeded resulting in the high interface roughness and the deterioration of the magnetic properties. In order to control the interfacial diffusion at the high temperature, we introduced ${\alpha}-Al_2O_3$ buffer layer ($110-{\AA}-thick$) in the interface of $Ba-ferrite/SiO_2$ thin film. During the annealing of $Ba-ferrite/{\alpha}-Al_2O_3/SiO_2$ thin film even at ${\sim}800^{\circ}C$, the interface was very smooth. The smooth interface of the film was also clearly shown by the cross-sectional FESEM. The magnetic properties, such as saturation magnetization 3nd intrinsic coercivity, were also enhanced, due to the inhibition of interfacial diffusion by the ${\alpha}-Al_2O_3$ buffer layer. Our study suggests that the ${\alpha}-Al_2O_3$ buffer layer act as a useful interfacial diffusion barrier in the $Ba-ferrite/SiO_2$ thin films.

• The Korean Journal of Nuclear Medicine
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• v.1 no.1
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• pp.37-54
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• 1967

The changes in histopathology of various organs and growth inhibition of the chick embryos incubated with radioactive sulfur ($^{35}S$) were experimentally studied. The various doses of $^{35}S$ were injected into the yolk sac at different intervals and the weight changes of the embryos were evaluated to determine the growth inhibition rates. The embryos sacrified on various incubation days were used for the study of histopathological changes in organs such as the bone, liver, kidney, gonad, and eye. Following were the results: 1) The weight changes of the $^{35}S$ treated groups were as follows: i. Embryos treated on the 5 th incubation day: No weight changes were noted on the 8th incubation day, however, the growth inhibition rate of 32.1% was noted in the group treated with $50{\mu}C$ and of 38.2% in the group treated with $150{\mu}C$ on the 12th incubation day. The rates were 9.1 and 12.1% on the 15th incubation day, and 6.5 and 10.6% on the 18th incubation day respectively. ii. Embryos treated on the 8th incubation day: The growth inhibition rates on the 12th, 15th and 18th incubation days in the groups treated with $50{\mu}C$ were 20.9, 25.9 and 18.8% and in those treated with $150{\mu}C$ were 20.0, 14.9 and 16.9% respectively. iii. Embryos treated on the 12th incubation day: The growth inhibition rates on the 15th and 18th in the groups treated with $50{\mu}C$ were 13.6 and 21.1% and in those treated with $150{\mu}C$ were 26.7 and 6.5% and in those treated with $250{\mu}C$ were 10.6 and 12.6% respectively. iv. Embryos treated on the 15th incubation day: The growth inhibition rates on the 18th in the groups treated with $50{\mu}C$ were 6.5% and in those treated with $150{\mu}C$ were 10.1% and in those treated with $250{\mu}C$ were 8.5% respectively. In summary, the longer the incubation days, the less the growth inhibition rates. II) The histopathological changes in the various organs were as follows: i. Bone: Hyperplasia and edematous changes of the bone cavity, irregular distribution of immature granular cells and increased number of the myeloblast, megakaryocyte and reticuloendothelial cells were noted. ii. Liver: The embryos treated with $150{\mu}C\;of\;^{35}S$ on the 8th incubation day showed necrosis and nucleolysis of the liver cell and abnormal enlargement of sinusoid on the 12th incubation day. The longer the incubation days, the more severe the changes such as the pyknotic artophy of the liver cells and heterochromatism. The embryos treated on the 5th incubation day with 50 and $150{\mu}C\;of\;^{35}S$ showed little changes, but sight enlargement and accumulation of serous fluid in the sinusoid on the 8th incubation day. iii. Kidney: No particular changes except atrophic changes of epithelium were noted in early stage, however, the infiltration of the granular cell and monocyte into the cortex and pyknotic changes of vascular glomeruli were noted in later stage. These changes were not closely related to the doses of $^{35}S$ given. iv. Gonad: The degenerative changes such as destruction of the immature germ cells, hyperplasia and vacuolization of the stroma were noted in testis and ovary. v. Eye: A slight distortion of the cornea and sclera was noted. The hypertrophy of inner layer and blood cell infiltration into the vascular layer of the choroid membrane were noted in embryo groups on the 12, 15 and 18th incubation days.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.343-351
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• 2021

Screening was conducted using 200 kinds of plant extracts to explore herbicide-activated components of plant origin. We separated and purified active substances and elucidated chemical structures using Ligularia stenocephala M., which has strong activity and has not yet been studied. When the solvent fractions of the leaves of Ligularia stenocephala M. were tested for their herbicidal activity, ethyl acetate and chloroform layer showed an inhibition rate of 95.2% and 94.1%, respectively. In particular, the chloroform layer exerted more than 50% herbicidal activity at 10 ppm. From the chloroform layer with the highest herbicidal activity, we isolated three herbicidal active compounds using stepwise chromatography, specifically silica gel or octadecyl silica (ODS) column chromatography, Sep-pak cartridges, and high performance liquid chromatography (HPLC). Based on the analysis of the active compounds using electron ionization mass spectroscopy (EI-MS), ¹H-NMR, and ¹³C-NMR, we identified the active compounds as euparin, 5,6-dimethoxy-2-isopropenylbenzofuran, and liguhodgsonal. When the herbicidal activity of the identified compounds was tested, euparin showed selective herbicidal activity for lettuce at 10^-3 M, and both liguhogsonal and 5,6-dimethoxy-2-isoprophenylbenzofuran exerted selective activity for rice and Echinochloa crus-galli.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1278-1285
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• 2008

The intestinal epithelial cell (IEC) layer of the intestinal tract makes direct contact with a number of microbiota communities, including bacteria known to have deleterious health effects. IECs possess innate protective strategies against pathogenic challenge, which primarily involve the formation of a physicochemical barrier. Intestinal tract mucins are principal components of the mucus layer on epithelial surfaces, and perform a protective function against microbial damage. However, little is currently known regarding the interactions between probiotics/pathogens and epithelial cell mucins. The principal objective of this study was to determine the effects of Lactobacillus on the upregulation of MUC2 mucin and the subsequent inhibition of E. coli O157:H7 attachment to epithelial cells. In the current study, the attachment of E. coli O157:H7 to HT-29 intestinal epithelial cells was inhibited significantly by L. acidophilus A4 and its cell extracts. It is also important to note that the expression of MUC2 mucin was increased as the result of the addition of L. acidophilus A4 cell extracts (10.0 mg/ml), which also induced a significant reduction in the degree to which E. coli O157:H7 attached to epithelial cells. In addition, the mRNA levels of IL-8, IL-1$\beta$, and TNF-$\alpha$ in HT-29 cells were significantly induced by treatment with L. acidophilus A4 extracts. These results indicate that MUC2 mucin and cytokines are important regulatory factors in the immune systems of the gut, and that selected lactobacilli may be able to induce the upregulation of MUC2 mucin and specific cytokines, thereby inhibiting the attachment of E. coli O157:H7.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.993-999
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• 2015

For the purpose of investigating the in vitro antidiabetic activity of a medicinal herb and herb mixture extracts prepared through traditional antidiabetic prescription, this study examined ${\alpha}$-glucosidase inhibitory activity. Tyrosinase, a type I membrane glycoprotein, is synthesized and glycosylated in the endoplasmic reticulum (ER) and Golgi. The enzyme is subsequently transported to melanosomes, where it participates in melanogenesis. Previous studies showed that disruption of early ER N-glycan processing by an ${\alpha}$-glucosidase inhibitor suppresses tyrosinase enzymatic activity and melanogenesis. According to the results, most oriental medicinal herbal extracts were stronger than acarbose and N-butyldeoxynojirimycin, known as an ${\alpha}$-glucosidase inhibitor. Interestingly, ethyl acetate layer of enzyme hydrolyzed Cheongsimyeonjaeum had an inhibitory effect on melanin synthesis in B16F1 cells, although it did not inhibit tyrosinase activity directly. Together, ${\alpha}$-glucosidase inhibition activity could be used to evaluate anti-melanogenesis, although cross-checking with melanin inhibitory assay is recommended.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.354-357
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• 2009

Three compounds, vanillic acid, p-hydroxylcinnamic acid, p-hydroxybenzaldehyde have been isolated from the ethylacetate extract of Sparganium stoloniferum Buch.-Ham roots using silica gel open column chromatography, preparative thin-layer chromatography (pTLC) and reverse phase high performance liquid chromatography. The structures of the compounds were established on the basis of IR, extensive 1D NMR, and MS analyses. The ethylacetate (EtOAc) extract, vanillic acid, and p-hydroxybenzaldehyde showed $\alpha$-glucosidase inhibition activity of 72.71%, 20.13%, and 30.42%, at the concentration of 10 ${\mu}g/mL$, respectively. The EtOAc extract exhibited strong antioxidant activity with an $IC_50$ value of 24.37 ${\mu}g/mL$ against DPPH radical scavenging activity, the vanillic acid, p-hydroxylcinnamic acid, and p-hydroxybenzaldehyde with an $IC_50$ value of 2.10 ${\mu}M$, 1.59 ${\mu}M$, and 2.72 ${\mu}M$ against DPPH, respectively.

• Corrosion Science and Technology
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• v.2 no.5
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• pp.233-237
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• 2003

Pickling inhibitors can be used to form an adsorbed layer on the metal surface to hinder the discharge of H^+$ and dissolution of metal ions. Nitrogen-containing inhibitors were selected as corrosion inhibitors for mild steel (MS) in pickling acid process. In this study, the addition of inhibitor, the pickling temperatures and the pickling times were the parameters to investigate the effects on the inhibition efficiency (IE) for MS by using weight loss measurement. Preliminary results show that the IE increased with the increase in pickling time from 10 minutes to 60 minutes, and the IE also increased with the increase in temperature at room temperature and $40^{\circ}C$. At the higher temperature. the IE values are higher and almost independent with the pickling time. Furthermore, the potentiodynamic polarization, open circuit corrosion potential-time and corrosion current-time studies show that nitorgen-containing inhibitor behaves predominantly as cathodic polarization. The roughness test and SEM investigation are also studied in this paper.