• Advances in materials Research
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• v.8 no.3
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• pp.219-235
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• 2019

This research is devoted to analyzing mechanical-thermal post-buckling behavior of a micro-size beam reinforced with graphene platelets (GPLs) based on geometric imperfection effects. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. The micro-size beam is considered to be perfect (ideal) or imperfect. Buckling mode shape of the micro-size beam has been assumed as geometric imperfection. Modified couple stress theory has been used for describing scale-dependent character of the beam having micro dimension. Via an analytical procedure, post-buckling path of the micro-size beam has been derived. It will be demonstrated that nonlinear buckling characteristics of the micro-size beam are dependent on geometric imperfection amplitude, thermal loading, graphene distribution and couple stress effects.

• Applied Microscopy
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• v.28 no.4
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• pp.503-512
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• 1998

Fine structure of the cutaneous pigments in the black widow spider, Latrodectus mactans are studied with light and electron microscopes. The cutaneous pigments are only observed in epidermal layer just beneath the cuticle. These pigments are compactly distributed around the spinnerets which located at caudal area of the abdomen. According to the fine structural characteristics of the pigment granules, two main types of guanine pigment granules-carotenoid vesicles and reflecting platelets - are observed in the cytoplasm of the epidermal cells. Morphological features of these pigment granules are characterized as the electron dense carotenoid vesicles and the electron lucent reflecting platelets. Marginal electron density of the carotenoid vesicle is different from that of internal region, whereas the reflecting platelets have laminated crystalline granules. Typiral structures of these pigment granules are very similar to those of invertebrate's chromatophores, especially erythrophores and iridophores. Moreover differentiation of these pigment granules are also originated from the small vesicles of Golgi complexes similarly to those of cutaneous chromatophores.

• Smart Media Journal
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• v.5 no.1
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• pp.137-142
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• 2016

In this paper, a multi-scale model is applied to the simulation of thrombus growth. This model includes macroscale model and microscale model. The former is used to model the plasma flow with Navier-Stokes equations, and the latter is used to model the platelets adhesion and aggregation, thrombus motion, and the surface expansion of thrombus. The force acting on platelets and thrombus from plasma is modeled by the drag force, and the forces from biochemical reactions are modeled by the adhesion force and the aggregation force. As more platelets are merged into the thrombus, the thrombus surface expands. We proposed a thrombus growth model for simulating the expansion of thrombus surface and tracking the surface by Level Set Methods. We implemented the computational model. The model performs well, and the experimental results show that the shape of thrombus in level set expansion form is similar with the thrombus in clinical test.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.645-654
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• 2023

Based on first-order shear deformation theory, a wave propagation model of graphene platelets reinforced metal foams (GPLRMFs) circular plates is built in this paper. The expressions of phase-/group- velocities and wave number are obtained by using Laplace integral transformation and Hankel integral transformation. The effects of GPLs pattern, foams distribution, GPLs weight fraction and foam coefficient on the phase and group velocity of GPLRMFs circular plates are discussed in detail. It can be inferred that GPLs distribution have great impacts on the wave propagation problems, and Porosity-I type distribution has the largest phase velocity and group velocity, followed by Porosity-III, and finally Porosity-II; With the increase of the GPLs weight fraction, the phase- and group- velocities for the GPLRMFs circular plate will be increased; With the increase of the foam coefficient, the phase- and group- velocities for the GPLRMFs circular plate will be decreased.

• Advances in materials Research
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• v.11 no.4
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• pp.331-349
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• 2022

In the present work, we proposed an analytical study on buckling behavior of a sandwich plate with polymeric core integrated with piezo-electro-magnetic layers such as BaTiO3 and CoFe2O4 reinforced by graphene platelets (GPLs). The Halpin-Tsai micromechanics model is used to describe the properties of the polymeric core. The governing equations of equilibrium are obtained from first-order shear deformation theory (FSDT) and the Navier's method is employed to solve the equations. The results show the effect of different parameters such as thickness, length, weight fraction of GPLs, and also effect of electric and magnetic field on critical buckling load. The result of this study can be obtained in the aerospace industry and also in the design of sensors and actuators.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.189-191
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• 1986

The effects of diterpene acids (i. e. pimaradienoic acid, kaurenoic acid, hydroxy cembratrienoic acid and dihydroxycembratetraenoic acid) on malondialdehyde generation by rat platelets in response to thrombin were studied. All the compounds inhibited the generation of MDA.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.132-132
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• 2001

To understand mechanism of benzoquinone-induced cytotoxicity, the roles of ATP and calcium in platelet toxicity and morphology changes was investigated. Using scanning electron microscopy, morphological changes to platelets following l,4-benzoquinone exposure consisted of membrane blebbing at 5 min which was significantly different from shape changes (pseudopod formation) observed in response to physiological agonists.(omitted)

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.100-100
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• 2004

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.77.1-77
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• 2002

Platelets arrest bleeding and repair damaged blood vessels. The purpose of this paper is to formulate a mathematical model for the control of platelet adhesion within the vasculature consistent with experimental findings, particularly those of Frenette, Ruggeri , Savage, Yuan, Lawrence and Springer. In addition to providing some, albeit rudimentary, insight into the behavior of platelets, a numerical simulation of this theoretical model may be useful in a systematic study of pathological cases. Glycoprotein receptor complex (GPIb/V/IX), found on the platelet surface membrane, binds to the adhesive protein and ligand von Willebrand factor (vWf), located within the sub-endothelium. The binding...

• Clinical and Experimental Pediatrics
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• v.49 no.8
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• pp.833-838
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• 2006

Giant platelet syndrome is a group of unique disorders characterized by the presence of abnormally large platelets, and usually accompanied by thrombocytopenia. Most cases of giant platelets are encountered in idiopathic thrombocytopenic purpura(ITP). In contrast, inherited giant platelet disorders, a group of heterogeneous diseases, are rare. Bernard-Soulier syndrome and its variants, and MYH9 related diseases have been defined at the molecular level. Abnormalities in transcription factors are implicated in a couple of macrothrombocytopenia syndromes. However, the molecular defects are unknown in gray platelet syndrome. It is important to make a proper diagnosis of congenital macrothrombocytopenia to avoid unnecessary medications and potentially dangerous treatment for presumed ITP.