1,721,031 research outputs found
Effect of evaporation temperature on the quality of colloidal crystals at the water-air interface
No full textThree-dimensional assemblies of 230 nm polystyrene (PS) colloidal particles were prepared on the suspension surface by evaporating the water in which the particles were suspended. The assembled colloidal particles were then transferred from the water surface onto a glass substrate by simple evaporation and sedimentation. In this study, we analyzed the structures of the colloidal assemblies formed at evaporation temperatures of 30, 40, 60, and 90 degreesC. At 30 degreesC, the rate of particle sedimentation is faster than the rate of crystallization on the water surface. Consequently, the PS particles randomly stack on the glass substrate before forming nuclei on the water surface. At higher evaporation temperatures, on the other hand, the rate of crystallization on the water surface exceeds the sedimentation rate, leading to an improvement in the quality of the resulting colloidal crystal. However, crystalline quality diminishes at evaporation temperatures greater than 60 degreesC because the high crystal growth rate leads to the formation of defects. As a result, there exists an optimum evaporation temperature that yields the highest quality crystals. Importantly, this novel process enables the rapid (within I h) fabrication of large-scale three-dimensional colloidal crystals
Three-dimensional self-assembly by ice crystallization
No full textThree-dimensional self-assembly of colloidal particles by ice crystallization is observed in a water based-colloidal suspension. When water containing polystyrene beads freezes and is crystalized into ice, the polystyrene beads are extruded outward from the ice regions. Consequently, the concentration of polystyrene beads increases rapidly and they are assembled together into a regular structure. As ice crystallization proceeds, a color appears abruptly. This indicates that the polystyrene beads have been assembled three dimensionally. The generated three-dimensional structure is confirmed by scanning electron microscopy images and the existance of a photonic band gap measured by an ultraviolet-visible spectrophotometer. The sample fabricated by this method is compared with a sample made by conventional vertical deposition. (C) 2002 American Institute of Physics
Rapid fabrication of two- and three-dimensional colloidal crystal films via confined convective assembly
No full textWe have developed a self-assembly method for fabricating well-ordered two-dimensional (213) and three-dimensional (313) colloidal crystal films. With a minute amount of a polystyrene colloidal suspension and without any special equipment, the proposed method can be used to rapidly deposit high-quality colloidal crystal films over a large surface area. By controlling the lift-up rate of the substrate, we modulate the meniscus thinning rate, which determines whether the colloidal particles are assembled into two or three dimensions. The proposed method can be used to fabricate not only monolayered colloidal crystals with colloidal particles of various sizes, but also multilayered colloidal crystals. In addition, the method enables us to fabricate binary colloidal crystals by consecutively depositing large and small particles
Fabrication and structural analysis of binary colloidal crystals with two-dimensional superlattices
No full textBinary colloidal crystals (see Figure) have been fabricated via the confined convective assembly method. By adjusting the ratio of the diameters of the small and large particles and the concentration of the small particles, various superlattices, including the previously reported LS2 and LS3 structures along with the new LS4 and LS5 structures, have been prepared
The probiotic mixture IRT5 ameliorates age-dependent colitis in rats
No full textTo investigate the anti-inflammatory effect of probiotics, we orally administered IRT5 (1 x 10(9) CPU/rat) for 8 weeks to aged (16 months-old) Fischer 344 rats, and measured parameters of colitis. The expression levels of the inflammatory markers' inducible NO synthase (iNOS), cyclooxygenase-2 (COX2), tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1 beta were higher in the colons of normal aged rats (18 months-old) than in the colons of normal young rats (6 months-old). Treatment with IRT5 suppressed the age-associated increased expression of iNOS, COX2, TNF-alpha, and IL-1 beta, and activation of NF-kappa B and mitogen-activated protein kinases. In a similar manner, the expression of tight junction proteins in the colon of normal aged rats was suppressed more potently than in normal young rats, and treatment of aged rats with IRT5 decreased the age-dependent suppression of tight junction proteins ZO-1, occludin, and claudin-1. Treatment with IRT5 suppressed age-associated increases in expressions of senescence markers p16 and p53 in the colon of aged rats, but increased age-suppressed expression of SIRT1. However, treatment with IRT5 inhibited age-associated increased myeloperoxidase activity in the colon. In addition, treatment with IRT5 lowered the levels of LPS in intestinal fluid and blood of aged rats, as well as the reduced concentrations of reactive oxygen species, malondialdehyde, and C-reactive protein in the blood. These findings suggest that IRT5 treatment may suppress age-dependent colitis by inhibiting gut microbiota LPS production. (C) 2015 Elsevier B.V. All rights reserved.1196sciescopu
Lactobacillus pentosus KF340 alleviates house dust mite-induced murine atopic dermatitis via the secretion of IL-10-producing splenic B10 cells
No full textIt has been reported that certain LAB isolated from fermented foods are effective suppressors of allergic symptoms. In the present study, the immunomodulatory effects of Lactobacillus pentosus KF340 (LPKF340), originally derived from a traditional fermented Korean food made mainly of cabbage or radish, were tested in a mouse model of allergic atopic dermatitis (AD). Prior treatment with LPKF340 could effectively alleviated pathologic AD symptoms induced by dust mite extract, including oedema and erythema, and decreased lymphocyte infiltration into the inflamed region. In the LPKF340-fed group, the level of allergic cytokine, IL-4, was reduced, while that of anti-inflammatory IL-10 was increased. It was found that splenic regulatory B10 cells were stimulated to produce IL-10 by dendritic cells (DCs) of Peyer's patch. This was dependent on the activity of B cell activating factor in DCs. Taken together, these results suggest that LPKF340 might act as an orally active immunomodulator for allergic AD. (C) 2016 Elsevier Ltd. All rights reserved.1111Nsciescopu
Fabrication of robust, high-quality two-dimensional colloidal crystals from aqueous suspensions containing water-soluble polymer
No full textIn this letter, we report that two-dimensional (2D) polystyrene colloidal crystals of much higher quality can be fabricated in a single-step confined convective assembly process by introducing water-soluble polymer into the colloidal suspension. The presence of the water-soluble polymer in the aqueous phase enables the colloidal particles to arrange into more hexagonally close-packed single crystalline domains, and thus reduces the defect density. In addition, the physical stability of the final 2D colloidal crystals is improved because each particle is bonded to neighboring particles and to the substrate by polymer bridges. (c) 2006 American Institute of Physics
Three-dimensional self-assembly of colloids at a water-air interface: A novel technique for the fabrication of photonic bandgap crystals
No full textProbiotics as an Immune Modulator
Full text linkProbiotics are nonpathogenic live microorganism that can provide a diverse health benefits on the host when consumed in adequate amounts. Probiotics are consumed in diverse ways including dairy product, food supplements and functional foods with specific health claims. Recently, many reports suggest that certain probiotic strains or multi strain mixture have potent immunomodulatory activity in diverse disorders including allergic asthma, atopic dermatitis and rheumatoid arthritis. However, underlying mechanism of action is still unclear and efficacy of probiotic administration is quite different depending on the type of strains and the amounts of doses. We and others have suggested that live probiotics or their metabolites could interact with diverse immune cells (antigen presenting cells and T cells) and confer them to have immunoregulatory functions. Through this interaction, probiotics could contribute to maintaining immune homeostasis by balancing proinflammatory and anti-inflammatory immune responses. However, the effect of probiotics in prevention or modulation of ongoing disease is quite diverse even within a same species. Therefore, identification of functional probiotics with specific immune regulatory property is a certainly important issue. Herein, we briefly review selection methods for immunomodulatory probiotic strains and the mechanism of action of probiotics in immune modulation.1127Ysciescopu
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