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Smaller Pores (smaller + pore)

Distribution by Scientific Domains
Medical Sciences50%

Terms modified by Smaller Pores

  • smaller pore size
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    Selected Abstracts

    Controlled Fabrication of Multitiered Three-Dimensional Nanostructures in Porous Alumina,

    ADVANCED FUNCTIONAL MATERIALS, Issue 14 2008
    Audrey Yoke Yee Ho
    Abstract We present the fabrication of multitiered branched porous anodic alumina (PAA) substrates consisting of an array of pores branching into smaller pores in succeeding tiers. The tiered three-dimensional structure is realized by sequentially stepping down the anodization potential while etching of the barrier layer is performed after each step. We establish the key processing parameters that define the tiered porous structure through systematically designed experiments. The characterization of the branched PAA structures reveals that, owing to constriction, the ratio of interpore distance to the anodization potential is smaller than that for pristine films. This ratio varies from 1.8 to 1.3,nm,V,1 depending on the size of the preceding pores and the succeeding tier anodization potential. Contact angle measurements show that the multitiered branched PAA structures exhibit a marked increased in hydrophilicity over two-dimensional PAA films. [source]

    Controlled application and removal of liposomal therapeutics: Effective elimination of pegylated liposomal doxorubicin by double-filtration plasmapheresis in vitro

    JOURNAL OF CLINICAL APHERESIS, Issue 2 2010
    Gerhard Pütz
    Abstract Introduction: Nanoscale particle-based drug delivery systems like long circulating liposomal doxorubicin show unique pharmacokinetic properties and improved toxicity profiles. Liposomal doxorubicin accumulates in tumor tissue due to the enhanced permeation and retention effect, but only a small fraction of a total dose reaches the tumor site. Accumulation of liposomal doxorubicin is much faster in tumor sites than in certain organs where dose limiting adverse effects occur. Finding a way to detoxify the predominant part of a given dose, circulating in the blood after accumulation is completed, will presumably reduce severe side effects during chemotherapy. Methods: Elimination properties of therapeutic used pegylated liposomal doxorubicin (Doxil®/Caelyx®) and therapeutic used double-filtration plasmapheresis systems were evaluated in vitro and in reconstituted human blood. Results: Liposomes can be filtered by appropriate membranes without leakage of doxorubicin up to a pressure of 1 bar. At higher pressures, liposomes (,85 nm) may squeeze through much smaller pores without significant leakage of doxorubicin, whereas decreasing pore size to ,8 nm leads to increased leakage of doxorubicin. With therapeutic used apheresis systems, liposomal doxorubicin can be efficiently eliminated out of buffer medium and reconstituted human blood. No leakage of doxorubicin was detected, even when liposomes were circulating for 48 h in human plasma before apheresis. Conclusions: Convenient apheresis techniques are capable of a safe and efficient elimination of therapeutic used liposomal doxorubicin in an experimental model system. J. Clin. Apheresis, 2010. © 2010 Wiley-Liss, Inc. [source]

    Characteristics and oil absorption of deep-fat fried dough prepared from ball-milled wheat flour

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2009
    Pariya Thanatuksorn
    Abstract BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (Tg), the physical properties of a polymer influences the formation of structure. The ball-milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball-milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball-milled for 0 to 10 h and then fried in frying oil at 150 °C for 1,7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non-milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non-milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball-milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non-milled wheat flour is higher than that of a sample prepared from ball-milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry [source]

    Incorporation of fibrin molecules containing fibrinopeptide A alters clot ultrastructure and decreases permeability

    BRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2007
    Veronica H. Flood
    Summary Previous studies have shown that a heterozygous mutation in the fibrinogen A, chain gene, which results in an A, R16C substitution, causes fibrinolytic resistance in the fibrin clot. This mutation prevents thrombin cleavage of fibrinopeptide A from mutant A, R16C chains, but not from wild-type A, chains. However, the mechanism underlying the fibrinolytic resistance is unclear. Therefore, this study investigated the biophysical properties of the mutant fibrin that contribute to fibrinolytic resistance. Fibrin clots made from the mutant fibrinogen incorporated molecules containing fibrinopeptide A into the polymerised clot, which resulted in a ,spiky' clot ultrastructure with barbed fibrin strands. The clots were less stiff than normal fibrin and were cross-linked slower by activated FXIII, but had an increased average fiber diameter, were more dense, had smaller pores and were less permeable. Protein sequencing showed that unclottable fibrinogen remaining in the supernatant consisted entirely of homodimeric A, R16C fibrinogen, whereas both cleaved wild-type , chains and uncleaved A, R16C chains were in the fibrin clot. Therefore, fibrinolytic resistance of the mutant clots is probably a result of altered clot ultrastructure caused by the incorporation of fibrin molecules containing fibrinopeptide A, resulting in larger diameter fibers and decreased permeability to fibrinolytic enzymes. [source]