Effects of ion motion on linear Landau damping

The effects of ion motion on Landau damping has been studied by the use of one-dimensional Vlasov-Poisson simulation. It is shown that the ion motion may significantly change the development of the linear Landau damping. When the ion mass is multiple of proton mass, its motion will halt the linear Landau damping at some time due to the excitation of ion acoustic waves. The latter will dominate the system evolution at the later stage and hold a considerable fraction of the total energy in the system. With very small ion mass, such as in electron-positron plasma, the ion motion can suppress the linear Landau damping very quickly. When the initial field amplitude is relatively high such as with the density perturbation amplitude δn/n0 > 0.1, the effect of ion motion on Landau damping is found to be weak or even ignorable

Entanglement and quantum phase transition in the one-dimensional anisotropic XY model

In this paper the entanglement and quantum phase transition of the anisotropic s=1/2 XY model are studied by using the quantum renormalization group method. By solving the renormalization equations, we get the trivial fixed point and the untrivial fixed point which correspond to the phase of the system and the critical point, respectively. Then the concurrence between two blocks are calculated and it is found that when the number of the iterations of the renormalziation trends infinity, the concurrence develops two staturated values which are associated with two different phases, i.e., Ising-like and spin-fluid phases. We also investigate the first derivative of the concurrence, and find that there exists non-analytic behaviors at the quantum critical point, which directly associate with the divergence of the correlation length. Further insight, the scaling behaviors of the system are analyzed, it is shown that how the maximum value of the first derivative of the concurrence reaches the infinity and how the critical point is touched as the size of the system becomes large.Comment: 10 pages, 5 figure

High level expression of human epithelial β-defensins (hBD-1, 2 and 3) in papillomavirus induced lesions

BACKGROUND: Epithelial defensins including human β-defensins (hBDs) and α-defensins (HDs) are antimicrobial peptides that play important roles in the mucosal defense system. However, the role of defensins in papillomavirus induced epithelial lesions is unknown. RESULTS: Papilloma tissues were prospectively collected from 15 patients with recurrent respiratory papillomatosis (RRP) and analyzed for defensins and chemokine IL-8 expression by quantitative, reverse-transcriptase polymerase chain reaction (RT-PCR) assays. HBD-1, -2 and -3 mRNAs were detectable in papilloma samples from all RRP patients and the levels were higher than in normal oral mucosal tissues from healthy individuals. Immunohistochemical analysis showed that both hBD-1 and 2 were localized in the upper epithelial layers of papilloma tissues. Expression of hBD-2 and hBD-3 appeared to be correlated as indicated by scatter plot analysis (r = 0.837, p < 0.01) suggesting that they were co-inducible in papillomavirus induced lesions. Unlike hBDs, only low levels of HD5 and HD6 were detectable in papillomas and in oral mucosa. CONCLUSION: Human β-defensins are upregulated in respiratory papillomas. This novel finding suggests that hBDs might contribute to innate and adaptive immune responses targeted against papillomavirus-induced epithelial lesions

Enhancing 1α-Hydroxylase Activity with the 25-Hydroxyvitamin D-1α-Hydroxylase Gene in Cultured Human Keratinocytes and Mouse Skin

1α,25-Dihydroxyvitamin D3 (1α,25(OH)2D3) and its analogs are used to treat psoriasis because of their potent antiproliferative activity. They have the potential for causing hypercalcemia, however, and patients often become resistant to the drug. We examined the feasibility of enhancing the cutaneous production of 1α,25(OH)2D3 using a human 25-hydroxyvitamin D-1α-hydroxylase (1α-OHase) plasmid. The 1α-OHase gene was fused to the green fluorescent protein gene (1α-OHase-GFP) driven by the cytomegalovirus promoter. Transfection of cultured normal human keratinocytes with the 1α-OHase-GFP plasmid resulted in a marked increase in the expression of 1α-OHase-GFP in the mitochondria. Transfection of keratinocytes with 1α-OHase-GFP or 1α-OHase plasmids in vitro enhanced the 1α-OHase activity substantially and increased the sensitivity of the keratinocytes to the antiproliferative effect of 25(OH)D3. The 1α-OHase-GFP plasmid was topically applied to shaved C57/BL6 mice. Twenty-four hours after topical application, immunohistochemical analysis of the skin for 1α-OHase-GFP revealed the presence of 1α-OHase-GFP in the epidermis and epidermal appendages including the hair follicles. The results from this study offer a unique new approach for the topical treatment of hyperproliferative disorders such as psoriasis and skin cancer using the 1α-OHase gene that could locally increase the production of 1α,25(OH)2D3 without causing hypercalcemia or resistance

A case study : basis for development of a curriculum based on images of self and environment.

<p><b>(a)</b> Right-handed twofold helical chain in 1 linked by intermolecular C–H···π interactions (red dotted line); <b>(b)</b> 3D supramolecular architecture construcated by C–H···π, O–H···O and C–H···O interactions.</p

Non-left-handed transmission and bianisotropic effect in a [pi]-shaped metallic metamaterials

A [pi]-shaped metallic metamaterial (geometrically, a combination medium of C-shaped resonators and continuous wires) is proposed to numerically investigate its transmission band near the resonant frequency, where otherwise it should be a negative-permeability (or negative-permittivity) stop band if either the C-shaped or continuous-wire constituent is separately considered. However, in contrast to the left-handed materials (LHMs)composed of split-ring resonators and wires as well as other metallic LHMs, this resonant transmission is a non-left-handed one as a result of the intrinsic bianisotropic effect attributed to the electrically asymmetric configuration of this [pi]-shaped metamaterial.Comment: 19 pages, 6 figure

Environment-friendly surface acoustic wave humidity sensor with sodium alginate sensing layer

A low-cost and environment-friendly surface acoustic wave (SAW) humidity sensor was fabricated on a quartz substrate using sol-gel/spin-coated sodium alginate (SA) sensing layer. The sensing mechanism is based on the frequency shift of the SAW sensor caused by both mass loading and electrical loading, with the former being the dominant factor. The SA film prepared in this study is an environment-friendly material with a large number of hydroxyl and carboxylate groups, which easily adsorb and react with H2O molecules to form hydrogen bonds. These adsorbed H2O molecules lead to significantly enhanced mass loading and signal responses of the SAW sensor. Electrical loading effect is also generated due to the transfer of hydrogen ions in the H2O molecules, which alters the electrical resistance and results in changes of resonant frequencies of the SAW device. When the relative humidity (RH) is increased from 35% to 85%, the responses of the SAW sensor with 1 wt% SA are significantly decreased. Whereas in a low humidity environment (e.g., RH <35%), the responses of the sensor show a linear relationship with the change of humidity. The developed humidity sensor shows good short-term/long-term stabilities and a low temperature coefficient of frequency