Tungsten Nitride, Well-Dispersed on Porous Carbon: Remarkable Catalyst, Produced without Addition of Ammonia, for the Oxidative Desulfurization of Liquid Fuel.

Polyanilines (pANIs), loaded with phosphotungstic acid (PTA), are pyrolyzed to get WO3 or W2 N (≈6 and ≈7 nm, respectively), which is well-dispersed on pANI-derived porous carbons (pDCs). Depending on the pyrolysis temperature, WO3 /pDC, W2 N/pDC, or W2 N-W/pDCs could be obtained selectively. pANI acts as both the precursor of pDC and the nitrogen source for the nitridation of WO3 into W2 N during the pyrolysis. Importantly, W2 N could be obtained from the pyrolysis without ammonia feeding. The obtained W2 N/pDC is applied as a heterogeneous catalyst for the oxidative desulfurization (ODS) of liquid fuel for the first time, and the results are compared with WO3 /pDC and WO3 /ZrO2 . The W2 N/pDC is very efficient in ODS with remarkable performance compared with WO3 /pDC or WO3 /ZrO2 , which is applied as a representative ODS catalyst. For example, W2 N/pDC shows around 3.4 and 2.7 times of kinetic constant and turnover frequency (based on 5 min of reaction), respectively, compared to that of WO3 /ZrO2 . Moreover, the catalysts could be regenerated in a facile way. Therefore, W2 N/pDC could be produced facilely from pyrolysis (without ammonia feeding) of PTA/pANI, and W2 N, well-dispersed on pDC, can be suggested as a very efficient oxidation catalyst for the desulfurization of liquid fuel.

High dose of glucose promotes chondrogenesis via PKCalpha and MAPK signaling pathways in chick mesenchymal cells.

We investigated the molecular mechanism of the glucose effect on the regulation of chondrogenesis. Exposure of chick wing bud mesenchymal cells to high concentrations of glucose stimulated chondrogenesis 2-fold to 2.5-fold without affecting cell proliferation. Glucose increased protein levels and the membrane translocation of protein kinase C alpha (PKCalpha), leading to a reduction of extracellular signal-regulated kinase (ERK) phosphorylation. Phosphorylation of p38 was also increased in a PKC-independent manner by glucose treatment. Glucose also increased cell adhesion molecules such as fibronectin, integrin beta1, and N-cadherin at early stages and then decreased these adhesion molecules at later stages of chondrogenesis. These alterations in protein level of adhesion molecules and in the phosphorylation of mitogen-activated protein kinases by glucose were blocked by inhibition of PKC or p38 but were synergistically increased by the inhibition of ERK. Therefore, high doses of glucose induce the down-regulation of ERK activity via PKCalpha and the up-regulation of p38 and result in the stimulation of chondrogenesis of chick mesenchymal cells through modulating the expression of adhesion molecules.