On a refinement of Wilf-equivalence for permutations

Recently, Dokos et al. conjectured that for all $k, m\geq 1$, the patterns $12\ldots k(k+m+1)\ldots (k+2)(k+1)$ and $(m+1)(m+2)\ldots (k+m+1)m\ldots 21$ are $maj$-Wilf-equivalent. In this paper, we confirm this conjecture for all $k\geq 1$ and $m=1$. In fact, we construct a descent set preserving bijection between $12\ldots k (k-1)$-avoiding permutations and $23\ldots k1$-avoiding permutations for all $k\geq 3$. As a corollary, our bijection enables us to settle a conjecture of Gowravaram and Jagadeesan concerning the Wilf-equivalence for permutations with given descent sets

Downregulation of protease activated receptor expression and cytokine production in P815 cells by RNA interference

Abstract Background Protease-activated receptors (PAR) are seven transmembrane G-coupled receptors comprising four genes (PAR-1 ~ PAR-4). Mast cell has been identified to be able to express PARs and release an array of cytokines upon activation. Recently, it was reported that interleukin (IL)-12 could regulate the expression of PARs in mast cells, and tryptase could induce IL-4 and IL-6 release from mast cells. In order to further investigate the issues, RNA interference (RNAi) technique was employed and small interfering RNAs (siRNA) of PARs were transfected in P815 cells. Results The results showed that siRNAs for PAR-1, PAR-2 and PAR-4 significantly downregulated expression of PAR-1, PAR-2 and PAR-4 mRNAs and proteins in P815 cells at 24, 48 and 72 h following transfection. siRNA PAR-1.2 and siRNA PAR-4.2 significantly reduced IL-12 induced upregulation of PAR-1 and PAR-4 expression, respectively when P815 cells were transfected with them for 48 h. siRNA PAR-2.3 blocked IL-12 induced downregulation of PAR-2 expression on both mRNA and protein levels. It was also observed that siRNA PAR-2.3 and siRNA PAR-1.2 reduced trypsin induced IL-4 release by approximately 92.6% and 65.3%, and SLIGKV-NH2 induced IL-4 release by 82.1% and 60.1%, respectively. Similarly, siRNA PAR-2.3 eliminated tryptase-induced IL-4 release by 75.3%, and siRNA PAR-1.2 diminished SFLLR-NH2 induced IL-4 release by 79.3%. However, siRNA PAR-1.2, siRNA PAR-2.3 and siRNA PAR-4.3 at 10 nM did not show any effect on tryptase-induced IL-6 release from P815 cells. Conclusion In conclusion, siRNAs of PARs can modulate PAR expression and PAR related cytokine production in mast cells, confirming that PARs are likely to play a role in allergic reactions.</p

Upregulation of Toll-like receptor (TLR) expression and release of cytokines from P815 mast cells by GM-CSF

<p>Abstract</p> <p>Backgroud</p> <p>Recently, mast cells have been recognized to express several Toll-like receptors (TLRs) on their membrane surfaces, and granulocyte-macrophage colony-stimulating factor (GM-CSF) was reported to be able to alter expression of TLRs and cytokine production in neutrophils. However, whether GM-CSF modulates the expression of TLR and cytokine production in mast cells is not clear.</p> <p>Results</p> <p>Using flow cytometry and real time PCR techniques, we found that GM-CSF upregulated expression of TLR3 and TLR7 in P815 cells in a concentration dependent manner. GM-CSF also provoked approximately up to 2.4 and 2.3 fold increase in IL-13 and IL-6 release from P815 cells, respectively following 16 h incubation. GM-CSF induced IL-13 secretion, TLR3 and TLR7 expression appeared to be through activation of mitogen-activated protein kinase (MAPK) and phosphotidylinositol 3-kinase (PI3K)/Akt signaling pathways, whereas GM-CSF elicited IL-6 release seemed via Akt signaling pathway. At 10 ng/ml, GM-CSF significantly enhanced R-848-induced IL-6 release from P815 cells.</p> <p>Conclusion</p> <p>The ability of GM-CSF in modulation of expression of TLR3 and TLR7 in P815 mast cells and in stimulation of IL-13 and IL-6 release from P815 mast cells in vitro suggests that GM-CSF might play an important role in enhancing the innate immune responses of mast cell to viral infection</p

Light-emitting GaAs nanowires on a flexible substrate

Semiconductor nanowire-based devices are among the most promising structures used to meet the current challenges of electronics, optics and photonics. Due to their high surface-to-volume ratio and excellent optical and electrical properties, devices with low power, high efficiency and high density can be created. This is of major importance for environmental issues and economic impact. Semiconductor nanowires have been used to fabricate high performance devices, including detectors, solar cells and transistors. Here, we demonstrate a technique for transferring large-area nanowire arrays to flexible substrates while retaining their excellent quantum efficiency in emission. Starting with a defect-free self-catalyzed molecular beam epitaxy (MBE) sample grown on a Si substrate, GaAs core–shell nanowires are embedded in a dielectric, removed by reactive ion etching and transferred to a plastic substrate. The original structural and optical properties, including the vertical orientation, of the nanowires are retained in the final plastic substrate structure. Nanowire emission is observed for all stages of the fabrication process, with a higher emission intensity observed for the final transferred structure, consistent with a reduction in nonradiative recombination via the modification of surface states. This transfer process could form the first critical step in the development of flexible nanowire-based light-emitting devices

Ten-fold enhancement of InAs nanowire photoluminescence emission with an InP passivation layer

In this letter, we demonstrate that a significant improvement of optical performance of InAs nanowires can be achieved by capping the core InAs nanowires with a thin InP shell, which successfully passivates the surface states reducing the rate of non-radiative recombination. The improvements have been confirmed by detailed photoluminescence measurements, which showed up to ten-fold increase in the intensity of room-temperature photoluminescence from the capped InAs/InP nanowires compared to the sample with core-only InAs nanowires. Moreover, the nanowires exhibit high stability of total photoluminescence emission strength across temperature range from 10 to 300 K as a result of strong quantum confinement. These findings could be the key to successful implementation of InAs nanowires into optoelectronic devices