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排序方式: 共有659条查询结果,搜索用时 78 毫秒
1.
Understanding interactions between functionalized gold nanoparticles (NPs) and lipid bilayers is essential for biomedical applications. Experiments have shown that NPs that are stable in solution can assemble into clusters when adsorbed to a lipid bilayer, suggesting that bilayer-mediated interactions facilitate assembly. In this work, we use coarse-grained molecular dynamics simulations to study bilayer-mediated interactions between NPs adsorbed to single- and multicomponent lipid bilayers. We perform unbiased simulations and umbrella sampling calculations using an implicit solvent force field to determine the thermodynamic contributions to assembly. We show that bilayer-mediated interactions drive the assembly of NPs into linear aggregates on liquid-disordered bilayers, which we attribute to a reduction in bilayer curvature. Similar bilayer-mediated interactions induce the alignment of NP clusters with phase boundaries in phase-separated bilayers. Together, these simulation results provide new physical insight into the balance of forces that dictate the assembly of charged NPs at multicomponent lipid bilayer interfaces. 相似文献
2.
Micrometer‐sized, monodisperse, magnetic composite particles were prepared by heating micrometer‐sized, monodisperse, hollow polystyrene/polydivinylbenzene composite polymer particles at 200°C for 4 h (particles had been dipped in pentacarbonyliron) and then washed in 12 N HCl and water. The hollow polymer particles were produced by seeded polymerization by the dynamic swelling method that was proposed by authors. The magnetic composite particles contained Fe3O4, the content of which was 49% based on total weight, and were attracted easily in water by a 1650 G magnet. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 428–433, 2003 相似文献
3.
Continuous emulsion polymerizations of vinyl acetate were conducted at 50°C in a single continuous Couette–Taylor vortex flow reactor (CCTVFR) using sodium lauryl sulfate as emulsifier and potassium persulfate as initiator. The polymerization can be carried out very smoothly and stably, but the steady‐state monomer conversion attained in a CCTVFR is not as high as that in a plug flow reactor (PFR), but only slightly higher than that in a continuous stirred tank reactor (CSTR), even if the Taylor number is adjusted to an optimum value. Also, the effects of operating variables, such as the emulsifier, initiator, and monomer concentrations in the feed and the mean residence time on the kinetic behaviors were almost the same as those observed in a CSTR. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2755–2762, 2002 相似文献
4.
在总结国内外地下水中污染物运移规律研究的基础上,阐述了地下水多孔介质中胶体与污染物协同运移的研究进展。讨论了胶体运移的基本过程、相关机理,探究污染物-胶体-微生物(生物胶体)协同运移的作用方式、影响因素、实验分析、模型构造,并指出该领域目前研究存在的主要问题,以及对该领域研究趋势的展望。 相似文献
5.
Edward Kostansek 《Journal of Coatings Technology and Research》2004,1(1):41-44
Coagulation of latex particles is most often carried out in the diffusion limited aggregation (DLA) regime where the time
for coagulation to take place is on the millisecond timescale. This process produces aggregates of low density, irregular
shape, and a broad particle size distributions. When the coagulation is carried out in the reaction limited aggregation (RLA)
regime, a coagulation time of about 1–120 sec, the system can be controlled by mixing to yield dense, spheroidal aggregates
with a very narrow particle size distribution. The important variables in the RLA process for butyl acrylate/methyl methacrylate
(BA/MMA) latexes were found to be mixing intensity, latex copolymer composition, and coagulation temperature. Dried aggregates
formed in the RLA process were found to have excellent powder flow properties and low dustiness. 相似文献
6.
Xiufeng Hao Xiaofeng Lu Zhenyu Li Yiyang Zhao Tiecun Shang Qingbiao Yang Ce Wang Lijuan Li 《应用聚合物科学杂志》2006,102(3):2889-2893
Polyacrylonitrile colloidal microspheres have been successfully prepared with different concentrations of electrospraying polyacrylonitrile solutions. The morphology of the colloidal spheres has two kinds of structures and is strongly affected by electrospray‐ionization parameters, such as the polymer concentration, applied voltage, and distance between the electrodes. The solvent can also affect the morphology of polyacrylonitrile. The optimum conditions for preparing colloidal spheres have been found, and differential scanning calorimetry results indicate that polyacrylonitrile colloid spheres are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2889–2893, 2006 相似文献
7.
Several samples of chitosan with different degrees of deacetylation and of different molecular weights were tested for the coagulation–flocculation of organic suspensions. Organic suspensions were prepared by mixing mushroom powder with tap water. Experiments were carried out at pH 5, pH 7, and pH 9. Because decreasing the pH reduced the amount of chitosan required to reach the required turbidity, at pH 9, a high concentration of chitosan was required to achieve the required treatment levels, whereas the difference was less significant between pH 7 and pH 5 (the required concentration of chitosan was halved). Though viscosity, correlated to the molecular weight of chitosan, affected treatment performance, its influence on the efficiency of coagulation–flocculation could be substantially reduced by slightly increasing the concentration of the polymer. This is of importance in the processing of industrial effluents: the aging of a chitosan solution, which may cause partial depolymerization, and loss of viscosity, will have a limited impact on process efficiency. The degree of deacetylation also has a limited effect on treatment performance, especially when the degree of deacetylation exceeds 90%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2070–2079, 2005 相似文献
8.
Saziye Ugur Ayse Alemdar Önder Pekcan 《Journal of Coatings Technology and Research》2005,2(7):565-575
This study reports a steady-state fluorescence (SSF) technique for studying film formation from surfactant-free polystyrene
(PS) latex and Na-montmorillonite (SNaM) composites. The composite films were prepared from pyrene (P)-labeled PS particles
and SNaM clay at room temperature and annealed at elevated temperatures in 10-min intervals above glass transition temperature
(t3) of polystyrene. During the annealing processes, the transparency of the film improved considerably. Scattered light (Is) and fluorescence intensity (Ip) from P were measured after each annealing step to monitor the stages of film formation. Evolution of transparency of composite
films was monitored by using photon transmission intensity, Itr. Scanning electron microscopy (SEM) was used to detect the variation in physical structure of annealed composite films. Minimum
film formation temperature, Tq, and healing temperatures, Th, were determined. Void closure and interdiffusion stages were modeled and related activation energies were determined. It
was observed that both activation energies increased as the percent of SNaM was increased in composite films. 相似文献
9.
纳米二氧化钛胶体对脱墨浆中DCS絮聚去除的GC-MS研究 总被引:1,自引:0,他引:1
采用GC-MS表征絮聚前后DCS组分变化的方法研究了纳米TiO2胶体对脱墨浆中DCS絮聚去除的机理.结果表明,该脱墨浆中DCS可硅烷化主要组分为树脂酸、脂肪酸、苯二甲酸酯类物质、2,2-双(4-羟苯基)丙烷和甾醇类等物质;纳米Ti O2胶体对上述多数组分有较强的絮聚去除能力,去除机理主要为“桥连絮聚”作用,且去除效果随组分分子极性增大而增强,随分子结构的位阻屏蔽作用增强而减弱. 相似文献
10.
Roqia Ashraf Tariq Maqbool Mushtaq A. Beigh Arvind H. Jadhav Hasham S. Sofi Faheem A. Sheikh 《应用聚合物科学杂志》2021,138(25):50594
There is an extensive possibility of improving characteristics of fibers used in hard tissue engineering, being hydrophobic and less osteoconductive, resulting in the dynamic growth of new tissues. The current work focuses on the fabrication of nanofibers incorporated with titanium dioxide (TiO2) ''as osteoconductive'' and silver (Ag) ''as self-healing'' nanoparticles (NPs). The incorporation of AgNO3 by in situ method not only helped to impart the antibacterial activity but also changed the contact angle from 81 ± 03° in the case of pristine nanofibers to 74 ± 03°, 61 ± 03°, 50 ± 08°, and 39 ± 1.1°, in the composite scaffolds containing 0.01, 0.03, 0.05, and 0.07 M of Ag salts. The incubation in simulated body fluid at 37°C to induce mineralization on nanofiber scaffolds indicated Ca and P crystals' formation. The antibacterial activity showed significantly more toxicity toward E. coli (8.3 ± 0.9 mm) than S. aureus (1.2 ± 0.1 mm). Biocompatibility studies using MTT assay on the pre-osteoblasts showed that both TiO2 and Ag NPs present in the nanofibers are non-toxic to the bone-like cells. However, results show that a higher concentration of Ag NPs (i.e., 0.07 M) is toxic to cells growing. Finally, all the results suggest that the nanofiber scaffolds have considerable scope for future bone tissue engineering materials. 相似文献