The effects of platelet activating factor and retinoic acid on the expression of ELAM-1 and ICAM-1 and the functions of neutrophils

Preincubation of pulmonary microvascular endothelial cells (PMVECs) with platelet-activating factor (PAF) for 3.5 h increased the adhesion rate of polymorphonuclear leukocytes (PMNs) to PMVECs from 57.3% to 72.8% (p < 0.01). Preincubation of PMNs with PAF also increased PMN-PMVEC adhesion rate. All-trans retinoic acid (RA) blocked the adherence of untreated PMNs to PAF-pretreated PMVECs but not the adherence of PAF-pretreated PMNs to untreated PMVECs. PAF increased the expression of intercellular adhesion molecule-1 (ICAM-1) and E-selection (ELAM-1) on PMVECs, PMN chemotaxis to zymosan-activated serum and histamine, and PMN aggregation and the release of acid phosphatase from PMNs. Co-incubation of RA inhibited PAF-induced PMN aggregation, the release of acid phosphatase from PMNs, and PMN chemotaxis to zymosan-activated serum and histamine while the expression of ICAM-1 and ELAM-1 did not change. Our results suggest that RA can be used to ameliorate PMN-mediated inflammation

Electronic strengthening of graphene by charge doping

pre-printGraphene is known as the strongest 2D material in nature, yet we show that moderate charge doping of either electrons or holes can further enhance its ideal strength by up to 17%, based on first-principles calculations. This unusual electronic enhancement, versus conventional structural enhancement, of the material's strength is achieved by an intriguing physical mechanism of charge doping counteracting the strain induced enhancement of the Kohn anomaly, which leads to an overall stiffening of the zone boundary K1 phonon mode whose softening under strain is responsible for graphene failure. Electrons and holes work in the same way due to the high electron-hole symmetry around the Dirac point of graphene, while overdoping may weaken the graphene by softening other phonon modes. Our findings uncover another fascinating property of graphene with broad implications in graphene-based electromechanical devices

Cancellation of divergences in unitary gauge calculation of H→γγH \to \gamma \gamma process via one W loop, and application

Following the thread of R. Gastmans, S. L. Wu and T. T. Wu, the calculation in the unitary gauge for the $H \to \gamma \gamma$ process via one W loop is repeated, without the specific choice of the independent integrated loop momentum at the beginning. We start from the 'original' definition of each Feynman diagram, and show that the 4-momentum conservation and the Ward identity of the W-W-photon vertex can guarantee the cancellation of all terms among the Feynman diagrams which are to be integrated to give divergences higher than logarithmic. The remaining terms are to the most logarithmically divergent, hence is independent from the set of integrated loop momentum. This way of doing calculation is applied to $H \to \gamma Z$ process via one W loop in the unitary gauge, the divergences proportional to $M_Z^2/M^3$ including quadratic ones are all cancelled, and terms proportional to $M_Z^2/M^3$ are shown to be zero. The way of dealing with the quadratic divergences proportional to $M_Z^2/M^3$ in $H \to \gamma Z$ has subtle implication on the employment on the Feynman rules especially when those rules can lead to high level divergences. So calculation without integration on all the $\delta$ functions until have to is a more proper or maybe necessary way of the employment of the Feynman rules.Comment: 1 figure, 34 pages (updated