Interfacial interaction is one of the most critical issues in carbon nanotube/polymer composites. In this paper the role of nonionic surfactant is investigated. With the surfactant as the processing aid, the addition of only 1 wt % carbon nanotubes in the composite increases the glass transition temperature from 63 °C to 88 °C. The elastic modulus is also increased by more than 30%. In contrast, the addition of carbon nanotubes without the surfactant only has moderate effects on the glass transition temperature and on the mechanical properties. This work points to the pathways to improve dispersion and to modify interfacial bonding in carbon nanotube/polymer composites.

In acute graft-versus-host disease (GVHD), naive donor CD4

Prevention of chronic graft-versus-host disease (cGVHD) remains a major challenge in allogeneic hematopoietic cell transplantation (HCT), due to limited understanding of cGVHD pathogenesis and lack of appropriate animal models. Here, we report that, in classical acute GVHD models with C57BL/6 donors and MHC-mismatched BALB/c recipients and with C3H.SW donors and MHC-matched C57BL/6 recipients, GVHD recipients surviving for more than 60 days after HCT developed cGVHD characterized by cutaneous fibrosis, tissue damage in the salivary gland and the presence of serum autoantibodies. Donor CD8+ T cells were more potent than CD4+ T cells for inducing cGVHD. The recipient thymus and de novo-generated, donor-derived CD4+ T cells were required for induction of cGVHD by donor CD8+ T cells but not by donor CD4+ T cells. Donor CD8+ T cells preferentially damaged recipient medullary thymic epithelial cells and impaired negative selection, resulting in production of autoreactive CD4+ T cells that perpetuated damage to the thymus and augmented the development of cGVHD. Short-term anti-CD4 monoclonal antibody treatment early after HCT enabled recovery from thymic damage and prevented cGVHD. These results demonstrate that donor CD8+ T cells cause cGVHD solely through thymic-dependent mechanisms, while CD4+ T cells can cause cGVHD through either thymic-dependent or independent mechanisms.

Caustic NaNO3 solutions containing dissolved Al were reacted with quartz sand at 89 degrees C to simulate possible reactions between leaked nuclear waste and primary subsurface minerals at the U.S. Department of Energy's Hanford site in Washington. Nitrate-cancrinite began to precipitate onto the quartz after 2-10 days, cementing the grains together. Estimates of the equilibrium constant for the precipitation reaction differ for solutions with 0.1 or 1.0 m OH- (log Keq = 30.4 +/- 0.8 and 36.2 +/- 0.6, respectively). The difference in solubility may be attributable to more perfect crystallinity (i.e., fewer stacking faults) in the higher-pH cancrinite structure. This is supported by electron micrographs of crystal morphology and measured rates of Na volatilization under an electron beam. Precipitate crystallinity may affect radionuclide mobility, because stacking faults in the cancrinite structure can diminish its zeolitic cation exchange properties. The precipitation rate near the onset of nucleation depends on the total Al and Si concentrations in solution. The evolution of experimental Si concentrations was modeled by considering the dependence of quartz dissolution rate on AI(OH)4- activity, cancrinite precipitation, and the reduction of reactive surface area of quartz due to coverage by cancrinite.

We reported that both donor CD4+ T and B cells in transplants were required for induction of an autoimmune-like chronic graft versus host disease (cGVHD) in a murine model of DBA/2 donor to BALB/c recipient, but mechanisms whereby donor B cells augment cGVHD pathogenesis remain unknown. Here, we report that, although donor B cells have little impact on acute GVHD (aGVHD) severity, they play an important role in augmenting the persistence of tissue damage in the acute and chronic GVHD overlapping target organs (i.e. skin and lung); they also markedly augment damage in a prototypical cGVHD target organ- the salivary gland. During cGVHD pathogenesis, donor B cells are activated by donor CD4+ T cells to upregulate MHC II and co-stimulatory molecules. Acting as efficient APCs, donor B cells augment donor CD4+ T clonal expansion, autoreactivity, IL-7Rα expression, and survival. These qualitative changes markedly augment donor CD4+ T cells' capacity in mediating autoimmune-like cGVHD, so that they mediate disease in the absence of donor B cells in secondary recipients. Therefore, a major mechanism whereby donor B cells augment cGVHD is through augmenting the clonal expansion, differentiation and survival of pathogenic CD4+ T cells.

• Antibodies produced by donor B cells are required for thymic and lymphoid damage in mice with chronic GVHD.• Antibody-producing donor B cells associate with infiltration of Th17 cells in the skin and perpetuation of cutaneous chronic GVHD in mice.

No abstract

Temperature-sensitive surfaces were prepared by grafting poly(N-isopropylacrylamide) (PNIPAAm) hydrogel on the surface of silicone wafers. The silicone wafer substrates were modified by organosilane (vinyltriethoxylsilane). They were further reacted with N-isopropylacrylamide (NIPAAm), using N,N′methylenebisacrylamide as the cross-linking agent, to generate the cross-linked PNIPAAm layer on the surface of the substrate. The surfaces modified by the cross-linked PNIPAAm layer were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and attenuated total reflectance-Fourier transform infrared (FTIR) spectroscopy. The reversible hydrophilic/hydrophobic properties of the surface were evaluated by the dynamic contact angle. The morphology of the surface modified by a crosslinked PNIPAAm layer can be turned from "sea island" to "mountain valley" by changing the molar ratio of NIPAAm to BisAAm and by varying the polymerization time. A completely hydrophilic surface (advancing contact angle ) 0°) was observed below 25 °C, and the surface became extremely hydrophobic (advancing contact angle ) 92°) above 40 °C. The sensitivity of the surfaces to temperature change can be improved by increasing the cross-linking density of the polymer layer and varying the polymerization time. The water meniscus height in a capillary tube, whose wall was coated by a cross-linked PNIPAAm layer, went up or down as the temperature changed to below or above the lower critical solution temperature of PNIPAAm. The differences in the water meniscus heights are 10 and 5 mm for a capillary tube with a diameter of 2 and 3 mm, respectively, corresponding to a change in temperature from 23 to 50 °C. The temperature-sensitive characteristics, which produce remarkable and rapid changes of surface properties, make this technology applicable for use as actuators, modulators, sensors, and switches.