High mobility group box 1 (HMGB1) is a novel late mediator of inflammatory responses that contributes to endotoxin-induced acute lung injury and sepsis-associated lethality. Although acute lung injury is a frequent complication of severe blood loss, the contribution of HMGB1 to organ system dysfunction in this setting has not been investigated. In this study, HMGB1 was detected in pulmonary endothelial cells and macrophages under baseline conditions. After hemorrhage, in addition to positively staining endothelial cells and macrophages, neutrophils expressing HMGB1 were present in the lungs. HMGB1 expression in the lung was found to be increased within 4 h of hemorrhage and then remained elevated for more than 72 h after blood loss. Neutrophils appeared to contribute to the increase in posthemorrhage pulmonary HMGB1 expression since no change in lung HMGB1 levels was found after hemorrhage in mice made neutropenic with cyclophosphamide. Plasma concentrations of HMGB1 also increased after hemorrhage. Blockade of HMGB1 by administration of anti-HMGB1 antibodies prevented hemorrhage-induced increases in nuclear translocation of NF-kappa B in the lungs and pulmonary levels of proinflammatory cytokines, including keratinocyte-derived chemokine, IL-6, and IL-1 beta. Similarly, both the accumulation of neutrophils in the lung as well as enhanced lung permeability were reduced when anti-HMGB1 antibodies were injected after hemorrhage. These results demonstrate that hemorrhage results in increased HMGB1 expression in the lungs, primarily through neutrophil sources, and that HMGB1 participates in hemorrhage-induced acute lung injury.
In situ metallocence polymerization was used to prepare nanocomposites of multiwalled carbon nanotubes (MWCNT) and high density polyethylene (HDPE). This polymerization method consists of attaching a metallocene catalyst complex onto the surface of MWCNT followed by surface-initiated polymerization to generate polymer brushes on the surface. All the procedures of polymerization made progress with one-pot process. The morphological observation of nanocomposites using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the nanotubes are uniformly dispersed throughout HDPE matrix. Physical properties of thermal and electrical conductivities and rheological response have been characterized. Since the carbon nanotubes are wrapped by PE molecules, the large interface provided by MWCNT's lead to strong phonon boundary scattering. Thus, the enhancement of thermal conductivity by the inclusion of nanotubes was quite restrictive. On the other hand, electrical conductivity and rheological properties show the property transition at the critical concentration of carbon nanotubes (percolation threshold). The DC conductivity increased with increasing weight fraction of MWCNT from 1.0 x 10(-13) S cm(-1) (neat HDPE) to 1.3 x 10(-2) S cm(-1) (HDPE/7.3 wt% of MWCNT) at room temperature and the electrical percolation threshold was ca. 7.3 wt%. The percolation threshold concentration of MWCNT for the rheological properties was ca. 8.7 wt%, similar to that of the electrical conductivity. Difference in the percolation behaviors between the MWCNT mixed nanocomposites and the PE-coated MWCNT nanocomposites is discussed in terms of the dispersion and the tube-tube distance of MWCNT.
A low energy Ar+ ion-beam was used to modify the surface of a high-density polyethylene
(HDPE) dry powder. The modification reaction was promoted by the oxygen gas injected during the
irradiation. This simple modification route is characterized as a heterogeneous, solvent-free, environmentally favorable process. The surface functional groups of the modified HDPE were confirmed with
X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy as being various oxygen-containing functional groups. The concentration of the functional groups varied rapidly with the irradiation
time, reached a maximum value and then slowly decreased. Because of the low-energy characteristics of
the ion beam, the changes in the molecular weight, the melting temperature, and the crystallinity of the
modified HDPE were not significant, as evidenced by gel-permeation chromatography and differential
scanning calorimetry. The rheological behavior of an HDPE/nylon 66 (Ny66) blend, which depends on
the blend composition, was complicated due to immiscibility whereas the ion-beam-irradiated HDPE/Ny66 blend showed a more systematic behavior. Also, the compatibility effect of ion-beam-treated HDPE
was investigated in the blend of HDPE/ Ny66. In the ion-beam-irradiated HDPE/blends, a significant
decrease in the domain size of the dispersed phase was observed. Theoretical models were used to estimate
the interfacial tension of HDPE/Ny66 blends. The calculated interfacial tension of an ion-beam-treated
HDPE/Ny66 blend was less than that of a nontreated HDPE/Ny66 blend, indicating a greater interaction
between the ion-beam-treated HDPE and the Ny66 phases. In addition, the mechanical properties of the
ion-beam-treated HDPE/Ny66 blend showed a positive deviation from the rule of mixture. Finally, an
explanation of the compatibilizing effect of ion-beam-treated HDPE is presented.
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