• Title/Summary/Keyword: degree of aggregation

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Simultaneous measurements of red blood cell aggregation and blood viscosity in a slit rheometry with light transmission analysis (광 투사법을 이용한 슬릿 점도계에서의 적혈구 응집성 및 점도 측정에 관한 연구)

  • Park, Myung-Su;Ku, Yun-Hee;Shin, Se-Hyun;Suh, Jang-Su
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1678-1681
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    • 2004
  • The light-transmission technique has been applied to a slit rheometer for measuring red blood cell aggregation as well as blood viscosity over a range of shear rates. For measurement of blood viscosity and aggregation, instantaneous pressure and transmit-light intensity are measured with time. Using a precision pressure measurement, one can determine the shear stress and shear rate. In addition, a transmitted light through a blood sample indicates degree of RBC aggregation. With abruptly flowing with high shear rate, RBCs rapidly disaggregate and the intensity of the transmitted light becomes low. When continuously flowing with decreasing shear rate, RBCs tend to re-aggregate and the corresponding transmit-intensity gradually increases with time. The light intensity as a degree of RBC aggregation is plotted against shear rate and compared with blood viscosity. The advantages of this design are dual measurement at a time, simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is contacted with blood sample.

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A Study on Factors that Influence the Degree of Participation in e-Marketplace (B2B e-Marketplace 참여도에 영향을 미치는 요인에 관한 연구)

  • 정승렬;배준열
    • Journal of Information Technology Applications and Management
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    • v.9 no.1
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    • pp.127-142
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    • 2002
  • This study examines various factors which influence the degree of Participation In B to B e-Marketplace. Based on literature review, six factors such as Information provision, IT infrastructure, trust, aggregation, new customer creation, and matching are identified. To collect the empirical data, survey methodology has been utilized. A total of 32 companies have returned completed responses. The results of analysis show high interdependencies between six factors and the degree of participation in e-Marketplace. In particular, aggregation is found to be the most influential factor. Additional analysis reveals that firms participating highly in e-Marketplace recognize aggregation and new customer creation the most important factors while less participating firms see IT infrastructure more important.

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The Effect of Endogenous and Exogenous Estrogen on Risk Factors of Coronary Heart Disease -Part II : On Platelet Aggregation- (내인성 및 외인성 Estogen이 관상동맥질환 위험인자에 미치는 영향 -제2보: 내인성 및 외인성 Estrogen이 혈소판 응집에 미치는 영향-)

  • 박유신
    • Journal of Nutrition and Health
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    • v.32 no.5
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    • pp.561-569
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    • 1999
  • In the atherosclerotic subjects, arterial endothelial cell injury and plaque formation are suspected to be strong causable factors in developing acute coronary syndrome, and it was revealed that platelets have a very important role in this case. Women are exposed to atherosclerosis at a different degree after menopause or oral contraception. The purpose of this study was to determine the effects of endogenous and exogenous estrogen on the degree of platelet aggregation in platelet rich plasma(PRP) in twenty nonsmoking healthy Korean women for 12 weeks. The subjects were assigned to three groups: (1) eight women aged 49 to 60(yr) for the postmenopausel(Pst) group, (2) eight, aged 22 to 30(yr) for the premenopausa(Pre) group, (3) four, aged 23 to 30(yr) for the oral contraceptive (OC) group which used triphasic OC formulation. Fasting blood sample were obtained from the subjects, (1) once per 6 weeks in the Pst group, (2) every phase of the menstrual cycle in the Pre group, (3) each once during and after OC administration in the OC group. ADP, collagen and epinephrine were used as aggregating reagents, and platelet aggregation and time(Δt: time reaching to the maximum point of aggregation) in PRP were measured at the maximum point of aggregation in five minutes. All the data were adjusted for dietary effects, personality type and body mass index(BMI) by using analysis of covariation(ANCOVA). Platelet aggregation to ADP and collagen(MADP and MCOLL) were not significantly different among the three groups, and Δt to ADP and collagen(TADP and TCOLL) were not either. But maximum platelet aggregability and Δt to epinephrine(MEPIN and TEPIN) were significantly different among the three groups, and the OC group showed the lowest value (p<0.01). Maxtimum platelet aggregability and Δt during the menstrual cycle were not significantly different in the Pre group. Any other significant differences in the maximum platelet aggregability and Δt were found between oral contraception phase and washing out phase(menstruation) in the OC group. In results, maximum platelet aggregability and aggregation time to ADP and collagen seemed not to be affected by endogenous and exogenous estrogen, even though MEPIN and TEPIN showed significantly low in the OC group among the three groups.

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A New Load Aggregation Method in Consideration of Non-linear Load (비선형 부하를 고려한 새로운 부하합성 기법)

  • Lee, Jong-Pil;Kim, Sung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.61 no.4
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    • pp.168-173
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    • 2012
  • The aggregation of group loads, which consists of the linear and the non-linear systems, yields the error involved in the reactive power aggregation, which is greater than the active power aggregation in the component based load modeling. Each individual reactive power in a group load affects the aggregated load different from composition rate. This paper proposes a new method that determines the degree of impacts by adjusting the coefficient of weight factors of each load using the least squares error method. The effectiveness of proposed algorithm is demonstrated by simulating three aggregation cases.

Improved Method for "Aggregation Based on Situation Assessment" ("상황 평가에 기반을 둔 병합"을 위한 개선 방법)

  • Choe, Dae-Yeong
    • The KIPS Transactions:PartB
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    • v.8B no.6
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    • pp.669-674
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    • 2001
  • In order to reflect the aggregation situation in the aggregation process, aggregation based on situation assessment (ASA) method was proposed in [1]. It consists of the situation assessment model (SAM) and the ASA algorithm. In the SAM, the value of parameter, p, is transformed into the nearest integer value [1]. The integer-typed output of SAM is used as input for an aggregation. The integer-typed output of SAM indicates the current degree of aggregation situation. The ASA algorithm produces at most finite several aggregation results between min and max. In the sequel, the ASA method can not properly handle the applications with the more sophisticated aggregation results between min and max. In order to solve this problem, we propose two improved ASA (I-ASA) methods. In these I-ASA methods, we allow the value of parameter of SAM to be a real number, and suggest two improved ASA algorithms to make continuous aggregation results between min and max. These I-ASA methods can handle both a precise aggregation and an approximate aggregation. Therefore, when compared to the ASA method [1], the proposed I-ASA methods have advantages in that they can handle the applications with the more sophisticated aggregation results and can be used in the more general applications for aggregations.

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Effect of Dietary Fatty Acids on Fatty Acid Composition of Platelet Phospholipids, Thromboxane B2 Formation, and Platelet Aggregation in Men (식이 지방산이 혈소판 인지질의 지방산 조성, 혈장 Thromboxane B2의 농도 및 혈소판 응집에 미치는 영향)

  • 오은주
    • Journal of Nutrition and Health
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    • v.32 no.4
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    • pp.384-393
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    • 1999
  • The degree of platelet aggregation, thromboxane B2(TXB2)formation and fatty acid composition of platelet phospholipids(PL) were investigated in 24 healthy male subjects who for five weeks consumed either corn oil(CO) rich in linoleic acid(LA), perilla oil (PO) rich in $\alpha$-linoleic acid($\alpha$-LAN), or canola oil(CNO) rich in oleic acid(OA) as a major fat source. Total fat intake was 30% of total calories and prescribed oil intake of each dietary group was 50% of the total fat intake. In the CO group, significantly decreased contents of polyunsaturated fatty acids(PUFA), n-6 PUFA, n-3 PUFA and eicosapentanoic acid(EPA) were observed, and significantly increased contents of OA and saturated fatty acids(SFA) were observed in platelet PL after 3 weeks and 5 weeks of dietary treatment. In the PO group, contents of OA and docosahexanoic acid(DHA) were increased, and the ratio of n-6/n-3 was decreased significantly in platelet PL after dietary treatment. The CNO group showed significatnlty decreased contents of PUFA, P/S ratio, n-6 PUFA, LA,(EPA+DHA)/arachidonic acid(AA), and significantly increased SFA contents after 3 weeks of the oil-based diet. The dietary-induced effects on fatty acid composition of platelet PL were observed mostly after 3 weeks of the oil-based diet. The dietary-induced effects on fatty acid composition of platelet PL were observed mostly after 3 weeks. Plasma TXB2 levels were increased after 3 and 5 weeks of dietary treatment. However, only the CO and CNO groups showed significantly increased plasma TXB2 levles after 3 and 5 weeks of dietary treatment. However, only the CO and CNO groups showed significantly increased plasma TXB2 levels after 5 weeks of experimental diets, when compared with initial values. Degree of platelet aggregation increased only in the CO group after dietary treatment. As a result, at week 5 the degree of platelet aggregation of the CO group was significantly higher than those of the PO and CNO groups. Among the three oil-based diets, the PO-based diet seems to have beneficial effects on atherosclerosis by influencing plasma TXB2 levels and the degree of platelet aggregation, while the CO-based diet showed the most adverse effects. Our results imply that plasma TXB2 levels might be affected by dietary fatty acid composition.

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Aggregation of Thin Copper Wire by Ball Milling Treatment (볼밀처리에 의한 구리세선의 응집)

  • Hwang, Jisu;Cho, Seong Su;Seong, Chang Jun;Yoo, Kyoungkeun
    • Resources Recycling
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    • v.29 no.4
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    • pp.67-72
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    • 2020
  • Recycling processes of spent copper wires cosisnt of several steps of cutting and chopping processes for peeling covering materials followed by gravity separation processes, where copper is recovered. Because copper thin wires could be lost during further recycling processes, the wire may need to be further treated. In the present study, the copper thin wire was treated with ball milling to prevent the loss. Since the aggregation of the copper wire could be formed by bending and entangling the copper wire each other, the degree of flexion of the copper wire was measured after ball milling. When the 0.5 cm and 3 cm copper wires were used, the 0.5 cm copper wire was not bent and the 3 cm copper wires were aggregated regardless of the ball addition. When the 1 cm and 2 cm copper wires were used, the degree of flexion was remarkable when the balls were added. In the tests using 2 cm copper wires, the aggregation ratio of the copper wire gradually increased with the amount of the 20 mm alumina ball, and when 200 ml of 30 mm alumina ball was used, the aggregation ratio increased to 89.29 %, but after increasing the ball amount further, the aggregation ratio decreased. Thus, it is expected that the loss of the copper wire could be reducedif when the copper thin wire is treated with ball milling by the aggregation of copper thin wires.

A Honey-Hive based Efficient Data Aggregation in Wireless Sensor Networks

  • Ramachandran, Nandhakumar;Perumal, Varalakshmi
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.998-1007
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    • 2018
  • The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

The Effects of the Fitness between the Task and the Information Characteristics on the User Satisfaction (과업 특성과 정보 특성간의 적합성이 사용자 만족도에 미치는 영향)

  • Han, Kyung-Il;Kim, Joon-Seuk
    • Asia pacific journal of information systems
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    • v.10 no.3
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    • pp.181-197
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    • 2000
  • The purpose of this study is to confirm whether the fit between the task and the information characteristics makes any effects on the user satisfaction. The task is defined as two sub-constructs representing the degree of exception and analyzability. The information characteristics is divided into the degree of aggregation, scope and timeliness of information. User satisfaction was used as a surrogate measure of the performance of information systems. The computer self-efficacy was used to control any confounding effects. Field research method using questionnaires was employed to empirically investigate the relationship among the variables. Findings of the study are summarized as follows: the fit between the task and the aggregation of information and between the task and the scope of information turned out to have significant effects on information system performance. The implication of such results is that under highly exceptional or less analyzable task environment, less-aggregated or broad information is more appropriate.

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The Effect of Polyethylene Oxide on the Aggregation State and Toxicity of Amphotericin B (폴리에틸렌 옥사이드가 암포테리신-B의 응집 특성 및 독성에 미치는 영향)

  • Yu, Bong-G.
    • 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.

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