Plasma and cellular fibronectin: distinct and independent functions during tissue repair

Fibronectin (FN) is a ubiquitous extracellular matrix (ECM) glycoprotein that plays vital roles during tissue repair. The plasma form of FN circulates in the blood, and upon tissue injury, is incorporated into fibrin clots to exert effects on platelet function and to mediate hemostasis. Cellular FN is then synthesized and assembled by cells as they migrate into the clot to reconstitute damaged tissue. The assembly of FN into a complex three-dimensional matrix during physiological repair plays a key role not only as a structural scaffold, but also as a regulator of cell function during this stage of tissue repair. FN fibrillogenesis is a complex, stepwise process that is strictly regulated by a multitude of factors. During fibrosis, there is excessive deposition of ECM, of which FN is one of the major components. Aberrant FN-matrix assembly is a major contributing factor to the switch from normal tissue repair to misregulated fibrosis. Understanding the mechanisms involved in FN assembly and how these interplay with cellular, fibrotic and immune responses may reveal targets for the future development of therapies to regulate aberrant tissue-repair processes

P3HT-Based Solar Cells: Structural Properties and Photovoltaic Performance

Each year we are bombarded with B.Sc. and Ph.D. applications from students that want to improve the world. They have learned that their future depends on changing the type of fuel we use and that solar energy is our future. The hope and energy of these young people will transform future energy technologies, but it will not happen quickly. Organic photovoltaic devices are easy to sketch, but the materials, processing steps, and ways of measuring the properties of the materials are very complicated. It is not trivial to make a systematic measurement that will change the way other research groups think or practice. In approaching this chapter, we thought about what a new researcher would need to know about organic photovoltaic devices and materials in order to have a good start in the subject. Then, we simplified that to focus on what a new researcher would need to know about poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends (P3HT: PCBM) to make research progress with these materials. This chapter is by no means authoritative or a compendium of all things on P3HT:PCBM. We have selected to explain how the sample fabrication techniques lead to control of morphology and structural features and how these morphological features have specific optical and electronic consequences for organic photovoltaic device applications

Synthesis and crystallization behavior of poly(L-lactide)-block-poly(epsilon-caprolactone) copolymer

We investigate, via wide and small angle X-ray scattering methods (WAXS and SAXS), differential scanning calorimetry (DSC), and optical microscopy (OM), the crystallization behavior of poly(L-lactide)-block-poly(epsilon -caprolactone) copolymer (PLLA-b-PCL) which is classified as a semicrystalline-semicrystalline block copolymer. The synthesis of PLLA-b-PCL was done by using a macroinitiator of hydroxy-terminated PCL (PCL-OH) with various molecular weights and followed by ring opening polymerization of L-lactide. The PLLA-b-PCL(H) with the number-average molecular weight (M-n) of 77,000 and the weight fraction of PCL block (w(PCL)) of 0.32 showed microphase separated structures at molten state up to 220 degreesC, as determined from theological measurement. But, the PLLA-b-PCL(L) with M-n = 19,000 and W-PCL = 0.374 became homogeneous at temperatures higher than 175 degreesC. From the crystallization behavior at 110 and 140 degreesC, we conclude that the chain folding of the crystalline PLLA block in PLLA-b-PCL(H) was quite different from that in PLLA-b-PCL(L). This result suggests that the chain segregation between the blocks at molten state affected significantly the chain folding of a semicrystalline block during the crystallization. (C) 2001 Published by Elsevier Science Ltd.X11125sciescopu

Supramolecular honeycomb by self-assembly of molecular rods in rod-coil molecule

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Orientational proliferation and successive twinning from thermoreversible hexagonal-body-centered cubic transitions

The deterministic proliferation of the orientation of hexagonally packed cylinders (HEX) from the twinned body-centered cubic (BCC) phase is investigated by synchrotron small-angle X-ray scattering (SAXS) and rheo-optical methods for di- and triblock copolymers of styrene and isoprene (SI and SIS). Repeated heating and cooling cycles starting from an initially aligned HEX produce a proliferation of cylinder orientations from successively twinned BCC states. The evolution of the orientation distribution of HEX cylinders produces a decrease in the birefringence and increase in the modulus with each successive generation. The cylinder axes of the degenerate HEX states coincide with the directions of the twinned BCC due to the epitaxial growth of cylinders from the twinned BCC. The distribution of the cylinder axes of the degenerate HEX states among the directions of the twinned BCC is found to be affected by memory of the prior HEX state, which decays with annealing time in the BCC state.X112929sciescopu

Characterization of autoantibodies to endothelial cells in systemic sclerosis (SSc): association with pulmonary fibrosis

To determine the prevalence and the characterization of antibodies to endothelial cells in patients with SSc, serum samples from 80 patients with SSc, 20 patients with systemic lupus erythematosus (SLE), and 20 healthy control subjects were examined by ELISA using cultured human umbilical vein endothelial cells (HUVEC), indirect immunofluorescence analysis (IIF), and immunoblotting using cytoplasmic extract of HUVEC. IgG and/or IgM isotype anti-endothelial cell antibodies (AECA) were demonstrated by ELISA in 43 of 80 patients with SSc (54%), in 15 of 20 patients with SLE (75%), and in none of 20 healthy control subjects. Immunofluorescence analysis on HUVEC substrate showed homogeneous cytoplasmic staining. Immunoblotting demonstrated that these patients had antibodies directed to one or several antigens of approximately 60, 90, 110 and 140 kD, and the most common responses were to the 90-kD antigen. By the immunofluorescence method using HUVEC, affinity-purified anti-90-kD antibodies showed identical cytoplasmic staining to that produced by sera positive for AECA. Furthermore, AECA were closely correlated with pulmonary fibrosis in patients with SSc. These findings suggest that patients with SSc have abnormal antibodies to endothelial cell antigens, and support the hypothesis that endothelial dysfunction is involved in the development of this disease