Luminescent conjugated polymers are widely used in organic optoelectronics. The device is fabricated by spin coating the polymer solutions into thin films. It is important to understand the chain conformation in the solution phase, which is mainly determined by the solubility properties of the solutes and the solvents. The purpose of this study is focused on the aggregate structures of MDMO-PPV polymer in the solution mixing of toluene, heptanes, and decahydronaphthalene. Compared to the polymer in toluene solution, the absorption and fluorescence spectra in the mixing solutions are red-shifted, which indicates the aggregation between polymer chains. In order to identify the aggregation is inter-chain or intra-chain effect, we perform concentration dependent measurements of the fluorescence spectra down to 10-10 M. Our results suggest that inter-chain aggregation is the major influence in the concentration. Since the intra-chain aggregation is strongly influenced by polymer concentration, we carry out the experiments to identify how the inter-chain effect influences at even lower concentrations. Fluorescence correlation spectroscopy (FCS) is used to determine the particle size at 10-12M concentration, which relates directly to the aggregation size. The results show that particle size in the poor solution is larger than that in the good solution. Therefore, we conclude that the change of the fluorescence spectra is caused by the inter-chain aggregation even at the concentration to 10-12M.

A molécula CD14 é uma glicoproteína expressa na membrana de leucócitos e células não mieloides, e pode ser encontrada tanto na membrana plasmática ancorada por glicosilfosfatidilinositol (GPI), como na forma solúvel no espaço extracelular. Esta molécula atua como co-receptor associado a receptores semelhantes a Toll (TLR), dentre eles o TLR4, e auxilia na ativação celular após reconhecimento de padrões moleculares associados a patógenos (PAMPs). Macrófagos ativados por produtos microbianos, como pelo lipopolissacarídeo (LPS), liberam citocinas e óxido nítrico (NO) que participam do processo inflamatório e sinalizam para células vizinhas ou distantes sobre a presença de agente agressor ou alterações teciduais. Após a ativação dos macrófagos, também são produzidos eicosanoides (EICs) que são mediadores lipídicos, como as prostaglandinas (PGs), os tromboxanos (TXs) e os leucotrienos (LTs). Os EICs são derivados em parte dos corpúsculos lipídicos (CLs) que são organelas citoplasmáticas funcionais, dinâmicas, ricas em lipídios e enzimas. Resultados anteriores do nosso grupo já demonstraram o envolvimento da molécula CD14 na produção de mediadores lipídicos, sem, contudo, elucidar os mecanismos. Assim, empregando macrófagos derivados da medula óssea (MDMO) estimulados com alta (500 ng/mL) e baixa (10 ng/mL) concentrações de LPS, tivemos como objetivo investigar a participação do CD14 na formação de CLs e na produção de prostanoides. A relevância da molécula CD14 foi ainda investigada na ativação de MDMO pelo ácido araquidônico exógeno (AA) (estímulo não específico). Nossos resultados demonstraram que a molécula CD14 contribui não somente para a formação de CLs e produção de prostanoides, como PGE2 e TXB2, mas também é essencial para a síntese de mediadores inflamatórios, como NO, TNF-? e IL-10, principalmente quando estimulados com baixa concentração de LPS / The CD14 molecule is a membrane-bound glycoprotein expressed by leukocytes and nonmyeloid cells, which can be attached to the plasma membrane by glycosylphosphatidylinositol (GPI) or in its soluble form in the extracellular space. This molecule acts as a co-receptor associated with Toll-like receptors (TLRs), including TLR4, and assists in cell activation after recognition of molecular patterns associated with pathogens (PAMPs). Macrophages activated by microbial products, such as lipopolysaccharide (LPS), release cytokines and nitric oxide (NO) that participate in the inflammatory process and signal to nearby or distant cells about the presence of an aggressive agent or tissue changes. After activation of macrophages, the lipid mediators denominated eicosanoids, such as prostaglandins (PGs), thromboxanes (TXs) and leukotrienes (LTs) are also produced. Eicosanoids are derived in part from lipid droplets (LDs) which are functional, dynamic cytoplasmic organelles, rich in lipids and enzymes. Previous results from our group have already demonstrated the involvement of the CD14 molecule in the production of lipid mediators, without, however, elucidating the mechanisms. Thus, using bone marrow-derived macrophages (BMDM) stimulated with high (500 ng/mL) and low (10 ng/mL) LPS concentrations, we aimed to investigate the participation of CD14 in the formation of LDs and in the production of prostanoids. The relevance of the CD14 molecule was further investigated by the activation of BMDM by exogenous arachidonic acid (AA) (nonspecific stimulus). Our results demonstrated that the CD14 molecule contributes not only to the formation of CLs and the production of prostanoids, such as PGE2 and TXB2, but it is also essential for the synthesis of inflammatory mediators, such as NO, TNF-? and IL-10, especially when stimulated with low LPS concentration