110 resultados para Computer-simulation


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The speciation and distribution of Zn(II) and the effect of Gd(III) on Zn(II) speciation in human blood plasma were studied by computer simulation. The results show that, in normal blood plasma, the most predominant species of Zn(II) are [Zn(HSA)] (58.2%), [Zn(IgG)](20.1%), [Zn(Tf)] (10.4%), ternary complexes of [Zn(Cit)(Cys)] (6.6%) and of [Zn(Cys)(His)H] (1.6%), and the binary complex of [Zn(CYS)(2)H] (1.2%). When zinc is deficient, the distribution of Zn(II) species is similar to that in normal blood plasma. Then, the distribution changes with increasing zinc(II) total concentration. Overloading Zn(II) is initially mainly bound to human serum albumin (HSA). As the available amount of HSA is exceeded, phosphate metal and carbonate metal species are established. Gd(III) entering human blood plasma predominantly competes for phosphate and carbonate to form precipitate species. However, Zn(II) complexes with phosphate and carbonate are negligible in normal blood plasma, so Gd(III) only have a little effect on zinc(II) species in human blood plasma at a concentration above 1.0x10(-4) M.

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The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by a Monte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it was attractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphology and structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introduced into the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymer blends depended on the chain structure of the A-B copolymer. Compared with alternating or random copolymer, the block copolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends. Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell structure was observed in the segment B composition region from 20% to 60%. However, if diblock copolymer composition in the blends is less than 40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%. Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increase continuously and their distribution became wider with decreasing B-segment component.

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A multiphase model of metal ion speciation in human interstitial fluid was constructed and the effect of Pr(III) on Ca(II) speciation was studied. Results show that free Ca2+, [Ca(HCO3)], and [Ca(Lac)] are the main species of Ca(II). Because of the competition of Pr(III) for ligands with Ca(II), the percentages of free Ca2+, [Ca(Lac)], and [Ca(His)(Thr)H-3] increase gradually and the percentages of CaHPO4(aq) and [Ca(Cit)(His)H-2] decrease gradually with the increase in the total concentration of Pr(III). However, the percentages of [Ca(HCO3)] and CaCO3(aq) first increase and then begin to decrease when the total concentration of Pr(III) exceeds 6.070 x 10(-4) M.

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The speciation and distribution of Gd(III) in human interstitial fluid was studied by computer simulation. Meantime artificial neural network was applied to the estimation of log beta values of complexes. The results show that the precipitate species, GdPO4 and Gd-2(CO3)(3), are the predominant species. Among soluble species, the free Gd(III), [Gd(HSA)], [Gd(Ox)] and then the ternary complexes of Gd(III) with citrate arc main species and [Gd-3(OH)(4)] becomes the predominant species at the Gd(III) total concentration or 2.2x10(-2)mol/L.

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A multi phase model of human blood plasma was developed and the Tb(Ⅲ) speciation in this system was studied. The results show that the speciation of Tb(Ⅲ) depends on the concentration of Tb(Ⅲ). When the concentration of Tb(Ⅲ) is below 4.000×10 -8 mol/L, most of Tb(Ⅲ) exists as soluble species while the concentration of Tb(Ⅲ) is in between 4.000 ×10 -8 mol/L and 1.667×10 -2 mol/L, precipitates(TbPO 4 and Tb 2 (CO 3 ) 3 ) are the dominant species of Tb(Ⅲ). Among soluble Tb(Ⅲ) ...

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Effect of Tb3+ on Ca2+ speciation in human plasma was studied by means of the computer program of MINTEQA2. When Tb3+ ions are not added into the system, Ca2+ ions mostly distribute in free Ca2+ (74.7%) and the surplus distributes in Ca2+ complexes, such as [CaHCO3](+) (7.9%),[Ca(Lac)](+) (6.4%), CaHPO4 (1.3%), [CaHistidinateThreoninateH(3)](3+) (2.4%), [CaCitrateHistidinateH(2)] (2.3%) and CaCO3 (1.1%). Tb3+ can compete with Ca2+ for inorganic as well as biological ligands. An increase of concentration of Tb3+ in the system results in an increase of content of free Ca2+ and a decrease of contents of Ca2+ complexes.

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A multi-phase model of Pr(III) speciation in human interstitial fluid was constructed and insoluble Pr(III) speciation was studied. When the total concentration of Pr(III) is below 8.401E-10 mol/L, soluble Pr(III) species are main species. With rising the total concentration of Pr(III), Pr(III) is firstly bound to phosphate to form precipitate of PrPO4, then bound to carbonate and another precipitate of Pr-2(CO3)(3) was obtained. When the total concentration is between 1.583E-9 mol/L and 4.000E-3 mol/L, the insoluble species are predominant Pr(III) species.

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Iodothyronine plays a major role in growth, basic metabolism and organ formation. It has an extremely limited source in the body. In this thesis, we designed iodothyronine(T4) as hapten. Then a single chain antibody displayed on phange was obtained from a human phage displaying a single chain antibody library. The specific genes of E3 was subcloned in P-5E vector. According to its amino acid sequences, we simulate its three dimention structure by computer. It has never been reported in PDB.

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Speciation of Pr(III) in human blood plasma has been investigated by computer simulation. The speciation and distribution of Pr(III) has been obtained. It has been found that most of Pr(III) is bound to phosphate and to form precipitate. The results obtained-are in accord with experimental observations.

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The insoluble species of Gd (III) in human blood plasma were investigated by computer simulation. The distribution of the Gd (I) species was obtained. It was found that most of the Gd (III) ions were bound to phosphate to form precipitate GdPO4 at the concentration of 1. 000 x 10(-7) mol/L and when the concentration of the Gd (III) increased to 3. 750 x 10(-4) mol/L, in excess of the concentration of phosphate, the Gd (III) ions were bound to carbonate to form another kind of precipitate, Gd-2 (CO3)(3).

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A multi-phase model was developed and Tb(III) speciation in human blood plasma was studied. At a concentration below 3.744x 10(-4) mol/L (or at the concentration), Tb(III) is mostly bound to phosphate to form precipitate of TbPO4. As the concentration of Tb(III) increases, phosphate is exceeded and another kind of precipitate of Tb-2(CO3)(3) appears. Among soluble Tb(III) species, Tb(III) mainly distribute in [Tb (Tf)] at low concentration and in [Tb (HSAA, [Tb-2 (Tf)], [Th (IgG)], [Tb (Lactate)](2+), [Tb (CitArgH)] and free Tb(III) at high concentration.

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Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3](-) is a predominant compound species of Ca (II). Gd (III) can compete with Ca (II) for biological molecules. The presence of Gd (III) results in a increase of concentration of free Ca (II) and a decrease of concentration of Ca (II) compounds.

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Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters are a = b = 20.3 angstrom, c = 3.52 angstrom, = = 90 degrees, = 120 degrees. The core of HPT is not perpendicular to the column. The angle between a axis and HPT core plane is 9 degrees which cannot be seen in b-c projection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.

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The physical vapor transport (PVT) method is being widely used to grow large-size single SiC crystals. The growth process is associated with heat and mass transport in the growth chamber, chemical reactions among multiple species as well as phase change at the crystal/gas interface. The current paper aims at studying and verifying the transport mechanism and growth kinetics model by demonstrating the flow field and species concentration distribution in the growth system. We have developed a coupled model, which takes into account the mass transport and growth kinetics. Numerical simulation is carried out by employing an in-house developed software based on finite volume method. The results calculated are in good agreement with the experimental observation.

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A correlative reference model for a computer simulation of molecular dynamics is proposed in this paper. Based on this model, a flexible displacement boundary scheme is naturally introduced and the dislocations emitted from a crack tip are presumed to continuously pass through the border of an inner discrete atomic region to pile up at an outer continuum region. The simulations for a Mo crystal show that the interaction between a crack and emitted dislocations results in the decrease in local stress intensity factor gradually.