• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.809-814
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• 2003

${\beta}-amyloid$ ($A{\beta}$) peptides from the proteolytic processing of ${\beta}-amyloid$ precursor protein (${\beta}-APP$) aggregates in the brain to form senile plaques, and their aggregation plays a key role in pathogenesis of Alzheimer's disease (AD). To isolate an active compound that has an $A{\beta}$ aggregation-inhibitory activity, 2,000 microbial metabolite libraries were screened based on their ability to inhibit $A{\beta}$ aggregation by using both Congo red and thioflavin T assays. As a result, a water-soluble fraction of a soil microorganism, KK565, showed a potent $A{\beta}$ aggregation-inhibitory activity. The strain was identified as Streptomyces species, based on the cultural and morphological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extract. In addition, the purification of active principle resulted in identifying a heat-unstable protein responsible for the $A{\beta}$ aggregation-inhibitory activity.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.119-129
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• 2014

PURPOSES : This investigational survey is to observe a proper spatial aggregation method for path travel time estimation using the hi-pass DSRC system. METHODS : The links which connect the nodes of section detectors location are used for path travel time estimation traditionally. It makes some problem such as increasing accumulation errors and processing times. In this background, the new links composition methods for spatial aggregation are considered by using some types of nodes as IC, JC, RSE combination. Path travel times estimated by new aggregation methods are compared with PBM travel times by MAE, MAPE and statistical hypothesis tests. RESULTS : The results of minimum sample size and missing rate for 5 minutes aggregation interval are satisfied except for JC link path travel time in Seoul TG~Kuemho JC. Thus, it was additionally observed for minimum sample size satisfaction. In 15, 30 minutes and 1 hour aggregation intervals, all conditions are satisfied by the minimum sample size criteria. For accuracy test and statistical hypothesis test, it has been proved that RSE, Conzone, IC, JC links have equivalent errors and statistical characteristics. CONCLUSIONS : There are some errors between the PBM and the LBM methods that come from dropping vehicles by rest areas. Consequently, this survey result means each of links compositions are available for the estimation of path travel time when PBM vehicles are missed.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.980-985
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• 2009

The study was designed to test anti-platelet effect and find out anti-platelet mechanism of extract from Gamisopunghwalheol-tang in vitro. The extract was investigated for the inhibition against the aggregation of human platelet suspensions induced from collagen by aggregometer. And also the extract was investigated for the inhibition against the aggregation of human platelet suspensions who is taking aspirin or clopidogrel induced from collagen by aggregometer. In collagen-induced platelet aggregation test, the extract significantly inhibited collagen-induced platelet aggregation in a concentration-dependent manner(p<0.05). The extract significantly inhibited collagen-induced platelet aggregation of human platelet who is taking aspirin or clopidogrel ing 0 mg/ml concentration(p<0.05). And the extract inhibited more ingpatients who is taking aspirin. These results show that the extract from Gamisopunghwalheol-tang has anti-platelet aggregation effect.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.460-466
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• 2006

We wondered whether the mechanisms of antiplatelet aggregation of DJS-WE were through multiple pathways. Danggijakyak-san(DJS) consisting of 6 herbes of Paeoniae Radix, Poria Cocos, Angelicae Sinensis Radix, Cnidii Rhizoma, Atractylodis Macrocephalae Rhizoma and Alismatis Rhizoma, is a crude mixture of a commonly used Korean herbal medicine. The water extract (DJS-WE) of DJS has been known to have an anti-platelet aggregation activity. We have reported that DJS-WE inhibited ADP-induced aggregation as well as arachidonic acid-induced aggregation of human platelet. Clinical studies on the cardiovascular effects of DJS-WE have been done in Korea. The DJS has been used as a remedy for gastrointestinal disorders (abdominal pain, dysentery), headache, amenorrhea, and postpartum hemorrhage. It has also been claimed to have a remarkable central stimulant effect, a transient hypertensive effect, and positive inotropic and chronotropic effects. In this paper, we evaluated the possible mechanisms of the antiplatelet activity of DJS-WE using human platelets. On the other hand, the role of DJS-ethanol extract on the inhibition of platelet aggregation and hemolytic effect have not yet been investigated in detail. We also used the method of activated partial thromboplastin times (APTT) for the first time to study the inhibition on platelet aggregation activity of DJS-ethanol extract. The effect of DJS-WE on hemolysis was also investigated. DJS-WE showed a high hemolysis ability on human blood.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.218-223
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• 2011

In this study, we investigated the effect of spinach saponin-enriched fraction (SSEF) on collagen (10 ${\mu}g/ml$)-stimulated platelet aggregation. SSEF inhibited collagen-induced platelet aggregation, and which was involved in the inhibition of thromboxane $A_2$ ($TXA_2$) production, an intracellular $Ca^{2+}$-agonist as an aggregation-inducing autacoidal molecule. In addition, SSEF significantly increased the formation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), intracellular $Ca^{2+}$-antagonists as aggregation-inhibiting molecules, in collagen-stimulated platelets. These results suggest that SSEF might inhibit $Ca^{2+}$-elevation and $TXA_2$ formation by increasing the production of $Ca^{2+}$-antagonistic molecules cAMP and cGMP. These mean that SSEF is a potent inhibitor of collagen-stimulated platelet aggregation. On the other hand, prothrombin time (PT) and activated partial thromboplastin time (APTT) were potently prolonged by SSEF. These findings suggest that SSEF prolongs the internal time between the conversion of fibrinogen to fibrin. Accordingly, our data demonstrate that SSEF may be a crucial tool for a negative regulator during platelet activation and blood coagulation on thrombotic diseases.

• Journal of Pharmaceutical Investigation
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• v.31 no.1
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• pp.7-12
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• 2001

Amphotericin B (AmB) is a drug of choice for the treatment of systemic fungal diseases, but its use is considerably limited due to a high incidence of toxicity, particularly nephrotoxicity. It has been demonstrated that the toxicity of AmB is caused by self-aggregated species of the drug and that unaggregated (monomeric) drug is nontoxic but still expresses antifungal activity. Poly (ethylene oxide) (PEO) is a water-soluble polymer, which may impact the aggregation state of AmB. We have studied the aggregation state of AmB as a function of PEO molecular weight and concentration. At 3,000 and 8,000 g/mole, there was minimal or no change of critical aggregation concentration (CAC) of AmB regardless of the concentration of polymer. By contrast at 20,000 g/mole, the CAC of AmB strikingly increased to 24.3 and $37.5\;{\mu}M$ at 5.0% and 10 % w/v of polymer, respectively. The critical overlap concentration (COC) of PEO 20,000 g/mole was 5.5%. It appears that an interaction between monomeric AmB and polymer coil increases above the COC, competing with self-aggregation of the drug. Accordingly, the degree of aggregation of AmB stayed low and the toxicity became less. There was no such effect at 3,000 and 8,000 g/mole of PEO, owing perhaps to small dimensions in comparison to AmB. Based upon these findings, less toxic AmB formulation may be developed by a pharmaceutical technique such as solid dispersion system containing both AmB and PEO 20,000 g/mole.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1295-1304
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• 2010

This paper proposes a fault-tolerant data aggregation which provides energy efficient and reliable data collection in wireless sensor networks. The traditional aggregation scheme does not provide the countermeasure to packet loss or the countermeasure scheme requires a large amount of energy. The proposed scheme applies caching and re-transmission based on the track topology to the adaptive timeout scheduling. The proposed scheme uses a single-path routing based on the traditional tree topology at normal, which reduces the dissipated energy in sensor nodes without any countermeasure against packet loss. The proposed scheme, however, retransmits the lost packet using track topology under event occurrences in order to fulfill more accurate data aggregation. Extensive simulation work under various workloads has revealed that the proposed scheme decrease by 8% in terms of the dissipated energy and enhances data accuracy 41% when the potential of event occurrence exists as compared with TAG data aggregation. And the proposed scheme decrease by 53% in terms of the dissipated energy and shows a similar performance in data accuracy when the potential of event occurrence exists as compared with PERLA data aggregation.

• Korean Journal of Acupuncture
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• v.24 no.3
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• pp.91-103
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• 2007

Objectives : The purpose of this study was to investigate the usability of live blood analysis on interior and exterior vascular laser irradiation therapy. Methods : We had analyzed the changing forms of the live blood sample with microscope before and after vascular laser irradiation therapy of blood. The live blood analysis was operated on Rouleau of red cell, erythrocyte aggregation, thrombocyte aggregation, uric acid crystals, red crystals, protoplasts. First, we analyzed all patients on each item, then did same thing classified two groups, Interior and exterior. Results : Rouleau of red cell, erythrocyte aggregation, thrombocyte aggregation, uric acid crystals, red crystals, protoplasts were decreased significantly, after interior and exterior aggregation, uric acid crystals. Interior vascular laser irradiation therapy was more effective than interior on Rouleau of red cell, erythrocyte aggregation, thrombocyte aggregation, uric acid crystals. Interior vascular laser irradiation therapy was more effective than exterior on red crystals, protoplasts. Conclusions : This study suggests that live blood analysis has the usability on vascular laser irradiation therapy. Then according to interior and exterior vascular laser irradiation therapy, the result has some different on each item. So it is better that choose the method, interior or exterior, for more effective therapy.

• Journal of the Korean Geographical Society
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• v.46 no.2
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• pp.197-211
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• 2011

Due to the complexity of spatial interaction and the necessity of spatial representation and modeling, aggregation of spatial interaction data is indispensible. Given this, the purpose of this paper is to evaluate the effects of modifiable areal unit problem (MAUP) on a spatial interaction model. Four aggregation schemes are utilized at eight different scales: 1) randomly select seeds of district and then allocate basic spatial units to them, 2) minimize the sum of population weighted distance within a district, 3) maximize the proportion of flow within a district, and 4) minimize the proportion of flow within a district. A simple Poisson regression model with origin and destination constraints is utilized. Analysis results demonstrate that spatial characteristics of residuals, parameter values, and goodness-of-fit of the model were influenced by aggregation scale and schemes. Overall, the model responded more sensitively to aggregation scale than aggregation schemes and the scale effect on the model was varied according to aggregation schemes.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1071-1075
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• 2010

Because a sensor node in wireless sensor networks(WSNs) has limited resources, such as battery capacity and memory, data aggregation techniques have been studied to manage the limited resources efficiently. Because sensor network uses wireless communication, a data can be disclosed by attacker. Thus, the study on data protection schemes for data aggregation is essential in WSNs. But the existing data aggregation methods require both a large number of computation and communication, in case of network construction and data aggregation processing. To solve the problem, we propose a data protection scheme based on Hilbert-curve for data aggregation. Our scheme can minimizes communications among neighboring sensor nodes by using tree-based routing. Moreover, it can protect the data from attacker by doing encryption through a Hilbert-curve technique based on a private seed, Finally, we show that our scheme outperforms the existing methods in terms of message transmission and average sensor node lifetime.