Ghost field realizations of the spinor W2,sW_{2,s} strings based on the linear W(1,2,s) algebras

It has been shown that certain W algebras can be linearized by the inclusion of a spin-1 current. This Provides a way of obtaining new realizations of the W algebras. In this paper, we investigate the new ghost field realizations of the W(2,s)(s=3,4) algebras, making use of the fact that these two algebras can be linearized. We then construct the nilpotent BRST charges of the spinor non-critical W(2,s) strings with these new realizations.Comment: 10 pages, no figure

Metabolomic profiling and stable isotope labelling of Trichomonas vaginalis and Tritrichomonas foetus reveal major differences in amino acid metabolism including the production of 2-hydroxyisocaproic acid, cystathionine and S-methylcysteine

Trichomonas vaginalis and Tritrichomonas foetus are pathogens that parasitise, respectively, human and bovine urogenital tracts causing disease. Using LC-MS, reference metabolomic profiles were obtained for both species and stable isotope labelling with D-[U-13C6] glucose was used to analyse central carbon metabolism. This facilitated a comparison of the metabolic pathways of T. vaginalis and T. foetus, extending earlier targeted biochemical studies. 43 metabolites, whose identities were confirmed by comparison of their retention times with authentic standards, occurred at more than 3-fold difference in peak intensity between T. vaginalis and T. foetus. 18 metabolites that were removed from or released into the medium during growth also showed more than 3-fold difference between the species. Major differences were observed in cysteine and methionine metabolism in which homocysteine, produced as a bi-product of trans-methylation, is catabolised by methionine γ-lyase in T. vaginalis but converted to cystathionine in T. foetus. Both species synthesise methylthioadenosine by an unusual mechanism, but it is not used as a substrate for methionine recycling. T. vaginalis also produces and exports high levels of S-methylcysteine, whereas only negligible levels were found in T. foetus which maintains significantly higher intracellular levels of cysteine. 13C-labeling confirmed that both cysteine and S-methylcysteine are synthesised by T. vaginalis; S-methylcysteine can be generated by recombinant T. vaginalis cysteine synthase using phosphoserine and methanethiol. T. foetus contained higher levels of ornithine and citrulline than T. vaginalis and exported increased levels of putrescine, suggesting greater flux through the arginine dihydrolase pathway. T. vaginalis produced and exported hydroxy acid derivatives of certain amino acids, particularly 2-hydroxyisocaproic acid derived from leucine, whereas negligible levels of these metabolites occurred in T. foetus

The principle of a virtual multi-channel lock-in amplifier and its application to magnetoelectric measurement system

This letter presents principles and applications of a virtual multi-channel lock-in amplifier that is a simple but effective method to recover small ac signal from noise with high presison. The fundamentals of this method are based on calculation of cross-correlation function. Via this method, we successfully built up a magnetoelectric measurement system which can perform precise and versatile measurements without any analog lock-in amplifier. Using the virtual multi-channel lock-in amplifier, the output of the magnetoelectric measurement system is extensively rich in magnetoelectric coupling behaviors, including coupling strength and phase lag, under various dc bias magnetic field and ac magnetic field.Comment: 11 pages, 6 figures. To be submitted to Rev. Sci. Instr

Improvement of the deep UV sensor performance of a β-Ga2O3 photodiode by coupling of two planar diodes

β -Ga 2 O 3 is one of the promising semiconductor materials that has been widely used in power electronics and ultraviolet (UV) detectors due to its wide bandgap and high sensitivity to UV light. Specifically, for the UV detection application, it has been reported that the photocurrent was in the scale of microamps ( μA ), which normally requires sophisticated signal processing units. In this work, a novel approach based upon coupling of two Schottky diodes is reported, leads to a substantial increase in photocurrent (~186 times) when benchmarked against a conventional planar UV photodiode. The detectivity and responsivity of the new device have also been significantly increased; the rectification ratio of this device was measured to be 1.7×107 with ultralow dark current, when measured in the reverse bias. The results confirm that the approach of coupling two Schottky diodes has enormous potential for improving the optical performance of deep UV sensors

The Strong Cell-based Hydrogen Peroxide Generation Triggered by Cold Atmospheric Plasma.

Hydrogen peroxide (H2O2) is an important signaling molecule in cancer cells. However, the significant secretion of H2O2 by cancer cells have been rarely observed. Cold atmospheric plasma (CAP) is a near room temperature ionized gas composed of neutral particles, charged particles, reactive species, and electrons. Here, we first demonstrated that breast cancer cells and pancreatic adenocarcinoma cells generated micromolar level H2O2 during just 1 min of direct CAP treatment on these cells. The cell-based H2O2 generation is affected by the medium volume, the cell confluence, as well as the discharge voltage. The application of cold atmospheric plasma (CAP) in cancer treatment has been intensively investigated over the past decade. Several cellular responses to CAP treatment have been observed including the consumption of the CAP-originated reactive species, the rise of intracellular reactive oxygen species, the damage on DNA and mitochondria, as well as the activation of apoptotic events. This is a new previously unknown cellular response to CAP, which provides a new prospective to understand the interaction between CAP and cells in vitro and in vivo. The short-lived reactive species in CAP may activate cells in vivo to generate long-lived reactive species such as H2O2, which may trigger immune attack on tumorous tissues via the H2O2-mediated lymphocyte activation

The Specific Vulnerabilities of Cancer Cells to the Cold Atmospheric Plasma-Stimulated Solutions.

Cold atmospheric plasma (CAP), a novel promising anti-cancer modality, has shown its selective anti-cancer capacity on dozens of cancer cell lines in vitro and on subcutaneous xenograft tumors in mice. Over the past five years, the CAP-stimulated solutions (PSS) have also shown their selective anti-cancer effect over different cancers in vitro and in vivo. The solutions used to make PSS include several bio-adaptable solutions, mainly cell culture medium and simple buffered solutions. Both the CAP-stimulated medium (PSM) and the CAP-stimulated buffered solution (PSB) are able to significantly kill cancer cells in vitro. In this study, we systematically compared the anti-cancer effect of PSM and PSB over pancreatic adenocarcinoma cells and glioblastoma cells. We demonstrated that pancreatic cancer cells and glioblastoma cells were specifically vulnerable to PSM and PSB, respectively. The specific response such as the rise of intracellular reactive oxygen species of two cancer cell lines to the H2O2-containing environments might result in the specific vulnerabilities to PSM and PSB. In addition, we demonstrated a basic guideline that the toxicity of PSS on cancer cells could be significantly modulated through controlling the dilutability of solution

On the double-band luminescence of ZnO nanoparticles

Two luminescence bands from zinc oxide (ZnO) nanoparticles are known and have been experimentally observed previously. The unanswered question concerns the mechanism leading to the visible spectrum in the blue or green region. So far there have been many postulations trying to elucidate this phenomenon, but none of them gives a mathematical expression that simultaneously explain these two spectra. Here we interpret this phenomenon as the combination of distribution functions and the density of states of electrons and holes, precisely the product of both. From the analysis, the narrow UV emission is predominantly attributed to the quantum confinement, and the product of the density of states and the distribution functions determines the visible spectrum. We find that varying the density and the effective mass of holes causes a pronounced effect on both UV and visible emissions, which reflects the fact that acceptors take the main responsibility in the experimental observations

Nonlinear Dynamics of Silicon Nanowire Resonator Considering Nonlocal Effect

In this work, nonlinear dynamics of silicon nanowire resonator considering nonlocal effect has been investigated. For the first time, dynamical parameters (e.g., resonant frequency, Duffing coefficient, and the damping ratio) that directly influence the nonlinear dynamics of the nanostructure have been derived. Subsequently, by calculating their response with the varied nonlocal coefficient, it is unveiled that the nonlocal effect makes more obvious impacts at the starting range (from zero to a small value), while the impact of nonlocal effect becomes weaker when the nonlocal term reaches to a certain threshold value. Furthermore, to characterize the role played by nonlocal effect in exerting influence on nonlinear behaviors such as bifurcation and chaos (typical phenomena in nonlinear dynamics of nanoscale devices), we have calculated the Lyapunov exponents and bifurcation diagram with and without nonlocal effect, and results shows the nonlocal effect causes the most significant effect as the device is at resonance. This work advances the development of nanowire resonators that are working beyond linear regime

Theoretical study of piezotronic metal–insulator–semiconductor tunnel devices

Piezotronics has been an emerging concept coupling piezoelectric and semiconducting properties with potential applications in sensors, flexible electronics and nanoelectromechanical systems (NEMS). Piezoelectric field is created under an applied strain, which controls the carrier generation, transport, separation or recombination processes at the interface or junction of the semiconductor devices. Based on the piezotronic theory, we present a one-dimensional model for the metal-insulator-semiconductor (MIS) tunnel diode based on the piezoelectric semiconductor. Analytical solutions of piezoelectric modulated tunneling are described to reveal the piezotronic effect on the MIS tunnel junction. Numerical simulation of the carrier transport properties is provided for demonstrating the piezotronic effect on MIS tunnel devices