54 research outputs found
Platelet-Activating Factor Induces TLR4 Expression in Intestinal Epithelial Cells: Implication for the Pathogenesis of Necrotizing Enterocolitis
Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in neonatal intensive care units, however its pathogenesis is not completely understood. We have previously shown that platelet activating factor (PAF), bacteria and TLR4 are all important factors in the development of NEC. Given that Toll-like receptors (TLRs) are expressed at low levels in enterocytes of the mature gastrointestinal tract, but were shown to be aberrantly over-expressed in enterocytes in experimental NEC, we examined the regulation of TLR4 expression and signaling by PAF in intestinal epithelial cells using human and mouse in vitro cell lines, and the ex vivo rat intestinal loop model. In intestinal epithelial cell (IEC) lines, PAF stimulation yielded upregulation of both TLR4 mRNA and protein expression and led to increased IL-8 secretion following stimulation with LPS (in an otherwise LPS minimally responsive cell line). PAF stimulation resulted in increased human TLR4 promoter activation in a dose dependent manner. Western blotting and immunohistochemical analysis showed PAF induced STAT3 phosphorylation and nuclear translocation in IEC, and PAF-induced TLR4 expression was inhibited by STAT3 and NFκB Inhibitors. Our findings provide evidence for a mechanism by which PAF augments inflammation in the intestinal epithelium through abnormal TLR4 upregulation, thereby contributing to the intestinal injury of NEC
State-of-the-Art of Cellulose Nanocrystals and Optimal Method for their Dispersion for Construction-Related Applications
In this paper, we reviewed the existing literature on the fabrication of nanocomposites based on cellulose and cellulose nanocrystals (CNCs), and analyzed their dispersion mechanism with respect to their use in the field of construction. First, the existing literature on CNC-based nanocomposites that exhibit the physical and chemical properties of nanocellulose and CNCs was reviewed. Next, keeping the use of these nanocomposites in the field of construction in mind, we determined the optimal mechanical method for their dispersion as an alternative to the currently used harmful chemical techniques. To this end, we evaluated the dispersibility of colloidal CNCs using two dispersion methods: magnetic stirring (for stirring times of 60 min, 120 min, and 180 min) and high-pressure dispersion (at pressures of 345 × 105 Pa, 1035 × 105 Pa, and 1587 × 105 Pa, and one to three dispersion passes). The optimal dispersion conditions were determined by analyzing the size and zeta potential of the CNC particles. It was found that the difference in the average diameter was reduced by approximately 76% at 1587 × 105 Pa during high-pressure dispersion
Correction: Park et al. Genetic Study in Korean Pediatric Patients with Steroid-Resistant Nephrotic Syndrome or Focal Segmental Glomerulosclerosis. J. Clin. Med. 2020, 9, 2013
In the original article [...
Ultrafast Graphene Light Emitters
Ultrafast
electrically driven nanoscale light sources are critical
components in nanophotonics. Compound semiconductor-based light sources
for the nanophotonic platforms have been extensively investigated
over the past decades. However, monolithic ultrafast light sources
with a small footprint remain a challenge. Here, we demonstrate electrically
driven ultrafast graphene light emitters that achieve light pulse
generation with up to 10 GHz bandwidth across a broad spectral range
from the visible to the near-infrared. The fast response results from
ultrafast charge-carrier dynamics in graphene and weak electron-acoustic
phonon-mediated coupling between the electronic and lattice degrees
of freedom. We also find that encapsulating graphene with hexagonal
boron nitride (hBN) layers strongly modifies the emission spectrum
by changing the local optical density of states, thus providing up
to 460% enhancement compared to the gray-body thermal radiation for
a broad peak centered at 720 nm. Furthermore, the hBN encapsulation
layers permit stable and bright visible thermal radiation with electronic
temperatures up to 2000 K under ambient conditions as well as efficient
ultrafast electronic cooling via near-field coupling to hybrid polaritonic
modes under electrical excitation. These high-speed graphene light
emitters provide a promising path for on-chip light sources for optical
communications and other optoelectronic applications
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