• YAKHAK HOEJI
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• v.49 no.4
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• pp.260-267
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• 2005

[ $PGE_1$ ] is an endogenous substance of potent vasodialator as well as inhibitor of platelet aggregation. It has been used therapeutically in peripheral arterial occlusive disease and impotence. Intracavernous injection of $PGE_1$ for erectile dysfunction has been established for several years as a treatment option for erectile dysfunction of diverse etiologies, but this mode of administration is limited by penile discomfort, pain at the injection site, inconvenience and noncompliance. As the matter of worse, the $\beta-hydroxy$ moiety of $PGE_1$ is extremely susceptible to dehydration in solution to give inactive $PGA_1$ and $PGB_1$. For the improvement of stability, rapid absorption at action site and the convenience of application, $PGE_1$ was formulated as urethral suppositories of three types of formulations, such as PEG, witepsol, and the mixture of PEG and witepsol. The stability test of $PGE_1$ and the release test in urinary suppositories were performed. Futhermore, the effect of enhancers and vehicle composition on the penetration of $PGE_1$ through excised rat skin was evaluated by permeability coefficient and enhancement ratio.

• Journal of Nutrition and Health
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• v.25 no.5
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• pp.339-350
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• 1992

This study was performed to investigate the effect on polyunsaturate fatty acid diets and feeding periods on the antithrombosis. the hematological changes in the blood and fatty acid compositions of platelets in rats. Each group of rats was fed a diet containing 20%(W/W) corn oil beef tallow sardine oil and the general stock diet for 10, 20. 40 and 80 days. Rats fed sardine oil diet showed significantly longer bleeding time than any other diet groups after 20 days feeding The whole blood clotting time of sardine oil group fed for 80 days was increased significantly. The number of platelet and the concentration of hemoglobin showed no significant difference among all groups. The number of white blood cell was decreased continously in sardine oil group after 10 days feeding. The level of malondialdehyde generation during thrombin-induced aggregation of platelets was decreased continously in sardine oil grou after 20 days feeding. With regard to the composition of platelet fatty acid the ratio of eicosapentaenoic acid(EPA 20: 5 $\omega$-3) to arachidonic acid(AA 20:4 $\omega$-6) was increased in sardine oil group but decreased in corn oil groups and beef tallow groups with days. In conclusion the rats fed sardine oil diet for more than 20 days showed the fact that EPA induced the antithrombosis. the changes in number of white blood cell and the fatty acid composition of platelets.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.289-293
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• 2013

In the noncoherent methods for UWB-IR (ultra-wideband impulse radio), block coded modulation (BCM) is better than the transmitted reference (TR) systems in terms of the energy efficiency and data rate. However, even BCM suffers from the performance degradation in the presence of strong inter-frame interference and inter symbol interference. We propose the transmitted reference based on the BCM (TR-BCM) which is the hybrid system of TR and BCM. Performance evaluation shows that the performance of TR-BCM is better than that of BCM in the high SNR range.

• Journal of Photoscience
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• v.5 no.1
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• pp.11-15
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• 1998

The texture change of non-linear optical molecules at the air/water interface was investigated as a function of surface pressure with Brewster angle microscopy. The texture change resulted from the aggregation of dye molecules is important to understand the film uniformity and grain formation process. The 4-Octadecylhydroxy-4'-nitrostilbene (OHNS) generated the small spots of size around 1$\mu$m. The spots exhibit high contrast with other film area and do not show angle dependent reflectivity change. It is interesting to observe that the size of the domain stays the same as the film pressure increases. At high surface pressure, the contrast ratio of domains becomes high, which means dense packing of OHNS. And, the size of domain grows. In the middle of domain, highly contrasted domains are formed. The first and the second order transitions of OHNS observed from surface pressure-area isotherm result from the two types of grains. The N,N-Dihexadecylcyanoaniline (DHCA) formed highly contrasted gains over entire region, and the grains are the double layers. The difference in Langmuir film of OHNS and DHCA at the air/water interface is consistent with the small tilt angle from the surface normal for OHNS and the large tilt angle for DHCA in the Langmuir-Blodgett films.

• Korean Journal of Pharmacognosy
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• v.18 no.1
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• pp.5-13
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• 1987

Male rats were fed diets containing perilla oil, sardine oil or corn oil for 15 weeks in order to investigate their antithrombotic effects. Rats given perilla oil and sardine oil diets showed significantly longer bleeding time, and lower level of malondialdehyde generation during thrombin-induced aggregation of platelets than rats given corn oil. With regard to the composition of platelet fatty acid, the ratio of eicosapentaenoic acid(EPA) $(20:5{\omega}3)$ to arachidonic acid $(20:4{\omega}6)$ of perilla oil, sardine oil and corn oil treated rats were 0.54, 0.96 and 0.01, respectively, suggesting that linolenic acid $(18:3{\omega}3)$ of perilla oil was metabolized to EPA which is known to have antithrombotic activity.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.491-498
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• 2015

Recognition of radar emitter signals is one of core elements in radar reconnaissance systems. A novel method based on singular value decomposition (SVD) and the main ridge slice of ambiguity function (AF) is presented for attaining a higher correct recognition rate of radar emitter signals in case of low signal-to-noise ratio. This method calculates the AF of the sorted signal and ascertains the main ridge slice envelope. To improve the recognition performance, SVD is employed to eliminate the influence of noise on the main ridge slice envelope. The rotation angle and symmetric Holder coefficients of the main ridge slice envelope are extracted as the elements of the feature vector. And kernel fuzzy c-means clustering is adopted to analyze the feature vector and classify different types of radar signals. Simulation results indicate that the feature vector extracted by the proposed method has satisfactory aggregation within class, separability between classes, and stability. Compared to existing methods, the proposed feature recognition method can achieve a higher correct recognition rate.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.459-467
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• 1989

When the sufactants are dissolved in water, they associate to form micelles and solubilize oil inside the micelle to form swollen micelles. Although spherical aggregates like micelles and swollen micelles occupy the same regions in the phase diagram of water-oil-surfactant systems, they are treated in different viewpoint for the formation of such aggregates. Hence a unified thermodynamic formalism for the formation of such structure is presented in this study. In all cases, the to ideal solution theory is applied for dilute system and the energy of formation is expressed as the sum of hydrophobic interaction energy and surface energy due to surfactant film. From the model, critical micelle concentration (CMC), average aggregation number, and solubilization ratio are predicted and compared with the known experimental observation.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3015-3020
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• 2014

The behavior of benzo[a]pyrene-7,8-dione (BPQ) in aqueous solution and its interaction with native DNA was investigated using conventional absorption and linear dichroism (LD) spectroscopy. The appearance of a broad absorption maximum at long wavelengths and its proportional relationship to solvent polarizability suggested that BPQ adopts a aggregated state for all solutions examined. Disappearance of this absorption band at higher temperatures in aqueous solution also supported BPQ aggregation. When associated with DNA absorption spectral properties were essentially the same as that in aqueous solution. However, two isosbestic wavelengths were found in the concentration-dependent absorption spectrum of the BPQ-DNA complex, suggesting the presence of at least two or more DNA-bound BPQ species. Both species produced $LD^r$ spectra whose magnitude in BPQ absorption region is larger or comparable to that in the DNA absorption region, suggesting that the molecular BPQ plane is near perpendicular relative to the local DNA helical axis. Therefore, BPQ molecules are aligned along the DNA stem in both DNA-aggregated BPQ species.

• Macromolecular Research
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• v.12 no.5
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• pp.501-506
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• 2004

We have investigated the spectral properties of DNA, including its electric absorption, circular and linear dichroism (CD and LD), and fluorescence emission, in the DNA-linear polyethyleneimine (LPEI) and DNA-branched polyethyleneimine (BPEI) complexes at various polymer concentrations. The spectral properties of both complexes are similar. We observed a relatively moderate change in the absorption and CD spectra at low amine/DNA phosphate (NIP) ratios (< 0.5), followed by a drastic collapse within the N/P range from 0.8 and 1.0. The absorption and CD spectra recovered as the N/P ratio increased to ca. 1.2. In contrast, the LD and emission of ethidium intercalated between the DNA bases decreased almost linearly at N/P ratios between 0.0 and 1.0. These spectra never recovered at higher N/P ratios. We believe that the moderate changes in the spectrum at low N/P ratios occurred because of electrostatic interactions between DNA and BPEI, while the collapsed spectra at N/P ratios between 0.5 and 1.5 occurred because of condensation/aggregation of the DNA. Considering the structure of the polymers, we suggest that the secondary amino group of LPEI and all three amino groups of BPEI are equally involved in DNA condensation.

• YAKHAK HOEJI
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• v.32 no.1
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• pp.26-39
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• 1988

Eudragit $RS^{\circledR}$ polymer was used as a wall material for the microencapsulation of aspirin by a phase separation method from chloroform-cyclohexane system with 5% polyisobutylene (PIB) in cyclohexane, and microcapsules obtained were evaluated by particle size analysis, scanning electron microscopy (SEM), drug release and drug stability test. With PIB as a coacervation inducing agent, smooth and tight microcapsules with less aggregation were obtained. Below 1 : 0.3 core-wall ratio, it was possible to coat individual particle. Variation of production conditions showed that increasing the proportion of wall material, particle size and wall thickness of microcapsules and the concentration of paraffin wax in cyclohexane as a sealant sustained drug release rates effectively. SEM confirmed that larger microcapsules after drug release did not rupture into smaller particles but contained a few small pores on the surface. Aspirin release from Eudragit $RS^{\circledR}$ coated microcapsules was independent of the pH of medium, and the mechanism of drug release from non-sealed and sealed microcapsules appeared to fit Higuchi matrix model kinetics. Aspirin in the mixture of aspirin microcapsules and sodium bicarbonate was by far more stable than that in the mixture of pure aspirin and sodium bicarbonate.