• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2002년도 Current Trends in Toxicological Sciences
• /
• pp.69-70
• /
• 2002

• 한국세라믹학회지
• /
• 제39권5호
• /
• pp.473-478
• /
• 2002

Flux법과 마이크로파 가열법으로 $Al_2(SO_4)_3+2Na_2SO_4$ 및 ${\gamma}-Al_2O_3+2Na_2SO_4$ 분말혼합물로부터 ${\alpha}-Al_2O_3$ 판상체(platelets)를 합성하였다. ${\alpha}-Al_2O_3$ 판상체 형성에 미치는 마이크로파의 영향을 조사하기 위하여 DTA-TG, XRD 및 SEM을 이용하였다. $Al_2(SO_4)_3+2Na_2SO_4$ 혼합물의 경우, 마이크로파로 가열된 시료는 재래식으로 가열된 시료에 비하여 입자의 크기가 작고 응집체로 구성된 ${\alpha}-Al_2O_3$ 판상체로 나타났다. ${\gamma}-Al_2O_3+2Na_2SO_4$ 혼합물의 경우, 마이크로파 가열에 의한 ${\alpha}-Al_2O_3$ 판상체 형성온도는 재래식 가열에 의한 형성온도 보다 낮았다. 또한 마이크로파로 가열된 시료의 형상은 재래식으로 가열된 시료의 형상과 유사하였다. 그러나 마이크로파로 가열된 시료는 재래식으로 가열된 시료에 비하여 입자의 크기가 작았다.

• Steel and Composite Structures
• /
• 재36권6호
• /
• pp.711-727
• /
• 2020

In the present research, the free vibration analysis of functionally graded (FG) nanocomposite deep spherical shells reinforced by graphene platelets (GPLs) on elastic foundation is performed. The elastic foundation is assumed to be Winkler-Past ernak-type. It is also assumed that graphaene platelets are randomly oriented and uniformly dispersed in each layer of the nanocomposite shell. Volume fraction of the graphene platelets as nanofillers may be different in the layers. The modified HalpinTsai model is used to approximate the effective mechanical properties of the multilayer nanocomposite. With the aid of the first order shear deformation shell theory and implementing Hamilton's principle, motion equations are derived. Afterwards, the generalized differential quadrature method (GDQM) is utilized to study the free vibration characteristics of FG-GPLRC spherical shell. To assess the validity and accuracy of the presented method, the results are compared with the available researches. Finally, the natural frequencies and corresponding mode shapes are provided for different boundary conditions, GPLs volume fraction, types of functionally graded, elastic foundation coefficients, opening angles of shell, and thickness-to-radius ratio.

• 한국식품위생안전성학회지
• /
• 제10권2호
• /
• pp.73-79
• /
• 1995

Incidents of seafood and massive fish kills have been rapidly increasing in both frequency and geographical distribution and the socioeconomic impacts brought by those incidents. However, the biological origins of those marine toxins have not been well clarified. Most of the marine organisms investigated are filter-feeder, which accumulate toxins from their food and/or their symbiotic microalgae. We have examined the action on rabbit platelets of marine toxins isolated from cultured dinoflagellates and sponge collected at Okinawa. Maitotoxin (MTX) is a water-soluble toxin isolated from the cultured dinoflagellate Gambierdiscus toxicus which causes a seafood poisoning in tropical regions. Zooxanthellatoxin A (ZT-A) was isolated from exteracts of cultured symbiotic dinoflagellate Symbiodinium sp. (socalled zooxanthella) from flatworms of the genus Amphiscolops collected at Okinawan marine sponge Theonella sp. MTX caused a disaggregation and a dissolution of large aggregates. ZT-A caused a dissolution of small aggregates followed by a increment of light tranmission. TZ-A caused an initial and transient shape change followed by a sustained aggregation and a increment of large aggregates. In conclusion, marine toxins exert unique patterns on the light trasmission and the size of aggregates in rabbit platelets by their concentrations and kinds

• 대한예방한의학회지
• /
• 제2권1호
• /
• pp.1-11
• /
• 1998

This experimental study was carried out to evaluate the effort of Lulianwendang on number of white blood cells and blood platelets in anti-neoplastic agents treated mice. The results were as follows; 1. The group of adriamycine treated and Lulianwendang administered mice were increased significantly in WBC as compared with control group.: 2. The group of cyclophosphamide injected and Lulianwendang administered mice were increased significantly in WBC as compared with control group. 3. The group of vincristin injected and Lulianwendang administered mice were increased significantly in W5C as compared with control group. 4. The group of adriamycine treated and Lulianwendang administered mice were increased significantly in blood platelets as compared with control group. 5. The group of cyclophosphamide injected and Lulianwendang administered mice were increased significantly in blood platelets as compared with control group. 6. The group of vincristin injected and Lulianwendang administered mice were increased significantly in blood platelets as compared with control group. According to the results, we can suggest that Lulianwendang has the hematopoiesis effects against anti-neoplastic agents treated mice.

• Steel and Composite Structures
• /
• 제27권3호
• /
• pp.255-271
• /
• 2018

This paper deals with the transient dynamic analysis and elastic wave propagation in a functionally graded graphene platelets (FGGPLs)-reinforced composite thick hollow cylinder, which is subjected to shock loading. A micromechanical model based on the Halpin-Tsai model and rule of mixture is modified for nonlinear functionally graded distributions of graphene platelets (GPLs) in polymer matrix of composites. The governing equations are derived for an axisymmetric FGGPLs-reinforced composite cylinder with a finite length and then solved using a hybrid meshless method based on the generalized finite difference (GFD) and Newmark finite difference methods. A numerical time discretization is performed for the dynamic problem using the Newmark method. The dynamic behaviors of the displacements and stresses are obtained and discussed in detail using the modified micromechanical model and meshless GFD method. The effects of the reinforcement of the composite cylinder by GPLs on the elastic wave propagations in both displacement and stress fields are obtained for various parameters. It is concluded that the proposed micromechanical model and also the meshless GFD method have a high capability to simulate the composite structures under shock loadings, which are reinforced by FGGPLs. It is shown that the modified micromechanical model and solution technique based on the meshless GFD method are accurate. Also, the time histories of the field variables are shown for various parameters.

• 고려인삼학회:학술대회논문집
• /
• 고려인삼학회 1993년도 학술대회지
• /
• pp.94-101
• /
• 1993

Lipophilic fraction(LF) from Panax ginseng C.A. Meyer inhibited the aggregation of human platelets induced by th rombin(0.1u/$m{\ell}$). LF and Molsidomine(vasodilator) induced the stimulation of cGMP - elevation and 50KD - Phosphorylation. and then the inhibition of 20KD - Phosphorylation in human platelets activated by thrombin. LF also inhibited the $Ca^{2-}-influx$ into platelets. When rat(SD : male) was fed with LF, the level of cGMP was increased in rat platelets stimulated by collagen and thrombin. On the other hand. verapamil, $Ca^{2-}-antagonist$ increased cAMP level ;n platelet stimulated by thrombin. but LF does not affected. However LF potently inhibited the thromboxane $A_2(TXA_2)$ production. The results suggest that the inhibitory effects of LF are mediated by regulation the phosphorylatior. of 50KD via cGMP-elevation and depend upon the decrease of $TXA_2$ level.

• Journal of Nutrition and Health
• /
• 제25권5호
• /
• pp.339-350
• /
• 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.

• 한국임상수의학회지
• /
• 제15권2호
• /
• pp.352-357
• /
• 1998

Effects of chicken egg white derivatives (EWD and EF-203) on the changes of blood cells and the neutrophil phagocytic activity were examined in the rats. Rats were administered orally with either EWD (200 mg/kg) or EF-203 (200 mg/kg) for 3 days. Thereafter, the changes of blood cell values (RBC, WBC, platelets, PCV, differential count of neutrophils) and the phagocytic activity of neutrophils were evaluated for 7 days. The numbers of WBC and the differential count of neutrophils of rats administered with either EWD or EF-203 were significantly increased (p

• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.55-58
• /
• 2004

Cell separation from peripheral blood was investigated using surface-modified polyurethane (PU) membranes with different functional groups. Both red blood cells and platelets could pass through unmodified PU and PU-SO$_3$H membranes, while the red blood cells preferentially passed through PU-N(C$_2$H$_{5}$ )$_2$ and PU-NHC$_2$H$_4$OH membranes. The permeation ratio of T and B cells was less than 25% for the surface-modified and unmodified PU membranes. CD34$^{+}$ cells have been recognized as various kinds of stem cells including hematopoietic and mesenchymal stem cells. The adhesiveness of CD34$^{+}$ cells on the PU membranes was found to be higher than that of red blood cells, platelets, T cells or B cells. Overall, the adhesiveness of blood cells on the PU membranes increased in the following order: red blood cells $\leq$ platelets ＜ T cells $\leq$ B cells ＜ CD34$^{+}$ cells. Treatment of PU-COOH membranes with a human albumin solution to detach adhered blood cells, allowed recovery of mainly CD34$^{+}$ cells in the permeate, while both red blood cells and platelets could be isolated in the permeate using unmodified PU membranes. The PU membranes showed different permeation and recovery ratios of specific cells depending on the functional groups attached to the membranes.mbranes.