Alternative scheme to generate a supersinglet state of three-level atoms

In this paper we propose an alternative scheme to generate a supersinglet state of three three-level atoms via a single-mode of a cavity QED based on the two-photon transitions described by the 'full microscopical Hamiltonian approach'. In it, three three-level atoms prepared in suitable initial states are sequentially sent through the cavity originally prepared in its vacuum state. After an appropriate choice of the atom-cavity interaction times plus a field detection the state that describes the whole atom-field system is projected in the desired supersinglet state. The fidelity and success probability of the state as well as the practical feasibility of the scheme are discussed.Comment: 10 pages, 3 figures, 4 table

Generation of two-photon EPR and Wstates

In this paper we present a scheme for generation of two-photon EPR and W states in the cavity QED context. The scheme requires only one three-level Rydberg atom and two or three cavities. The atom is sent to interact with cavities previously prepared in vacuum states, via two-photon process. An appropriate choice of the interaction times one obtains the mentioned state with maximized fidelities. These specific times and the values of success probability and fidelity are discussed.Comment: 4 pages, 5 figure

CFD Simulations of Bubble Column Equipped with Bundles of Concentric Tubes

Bubble column reactors are multiphase contactors that have found several industrial applications owing to various attractive features including excellent thermal management, low maintenance cost due to simple construction and absence of moving parts. In order to attain desired performance for a given application, these reactors are usually equipped with internals such as vertical tube bundles to facilitate heat transfer. The column hydrodynamics and turbulence parameters are altered when the column is occluded with internals which adds to the complexity of the problem. The use of Computational Fluid Dynamics (CFD) tools for the study of multiphase flows has gained a lot of traction over the recent years. In the current study, CFD is applied to a 2-Dimensional Eulerian-Eulerian model coupled with Population Balance Model (PBM) to simulate bubble column reactors in the presence and absence of internals. The significance of various interfacial forces on the numerical solution has been reviewed. Based on this, a suitable model is chosen which appropriately simulates the gas-liquid flow and has been selected to perform flow transition studies which covers the bubbly, transition and churn-turbulent regime. An increase in hydrodynamic parameters like centerline liquid axial velocity and gas holdup was noticed when the bubble column was occluded with circular tube internals. Furthermore, when dense vertical internals were introduced, the hydrodynamic values varied and consequently increased. When internals were added, a significant variation was noticed in the flow pattern which contributed to superior qualities of mixing

White Light-Informed Optical Properties Improve Ultrasound-Guided Fluorescence Tomography of Photoactive Protoporphyrin IX

Subsurface fluorescence imaging is desirable for medical applications, including protoporphyrin-IX (PpIX)-based skin tumor diagnosis, surgical guidance, and dosimetry in photodynamic therapy. While tissue optical properties and heterogeneities make true subsurface fluorescence mapping an ill-posed problem, ultrasound-guided fluorescence-tomography (USFT) provides regional fluorescence mapping. Here USFT is implemented with spectroscopic decoupling of fluorescence signals (auto-fluorescence, PpIX, photoproducts), and white light spectroscopy-determined bulk optical properties. Segmented US images provide a priori spatial information for fluorescence reconstruction using region-based, diffuse FT. The method was tested in simulations, tissue homogeneous and inclusion phantoms, and an injected-inclusion animal model. Reconstructed fluorescence yield was linear with PpIX concentration, including the lowest concentration used, 0.025  μg/ml . White light spectroscopy informed optical properties, which improved fluorescence reconstruction accuracy compared to the use of fixed, literature-based optical properties, reduced reconstruction error and reconstructed fluorescence standard deviation by factors of 8.9 and 2.0, respectively. Recovered contrast-to-background error was 25% and 74% for inclusion phantoms without and with a 2-mm skin-like layer, respectively. Preliminary mouse-model imaging demonstrated system feasibility for subsurface fluorescence measurement in vivo. These data suggest that this implementation of USFT is capable of regional PpIX mapping in human skin tumors during photodynamic therapy, to be used in dosimetric evaluations

Review of Fluorescence Guided Surgery Visualization and Overlay Techniques

In fluorescence guided surgery, data visualization represents a critical step between signal capture and display needed for clinical decisions informed by that signal. The diversity of methods for displaying surgical images are reviewed, and a particular focus is placed on electronically detected and visualized signals, as required for near-infrared or low concentration tracers. Factors driving the choices such as human perception, the need for rapid decision making in a surgical environment, and biases induced by display choices are outlined. Five practical suggestions are outlined for optimal display orientation, color map, transparency/alpha function, dynamic range compression, and color perception check

Polyelectrolyte Complexation of Chitosan and WS₂ Nanotubes

The inclusion of tungsten disulphide nanotubes (WS2 NTs) in chitosan, plasticized with glycerol, facilitates the formation of a polyelectrolyte complex. The glycerol interrupts the intramolecular hydrogen bonding between chitosan chains allowing positively charged protonated amines of chitosan to form a complex with negatively charged oxygen ions chemisorbed to the tungsten atoms in defects. These interactions, with the unique mechanical and chemical properties of WS2 NTs, result in a chitosan film with superior properties relative to unfilled chitosan. Even at low WS2 NT loadings (≤1 wt%), the Young\u27s modulus (E) increases by 59%, tensile strength (σ) by 40% and tensile toughness by 74%, compared to neat chitosan, without sacrificing ductility. Addition of highly dispersed WS2 NTs significantly improves the gas barrier properties of chitosan, with a 50% reduction in oxygen permeability, while the addition of both glycerol and WS2 NTs to chitosan effectively reduces the carbon dioxide permeability by 80% and the water vapor transmission rate by 90%. The intrinsic antimicrobial efficacy of chitosan against both Gram-positive and Gram-negative bacteria is enhanced on inclusion of WS2 NTs. Polyelectrolyte complexation of WS2 NTs and glycerol-plasticized chitosan provides a cost-effective, sustainable route to biodegradable films with desirable mechanical, gas barrier properties, and antimicrobial efficacy suitable for food packaging applications

Interaction between Mas1 and AT1RA contributes to enhancement of skeletal muscle angiogenesis by angiotensin-(1-7) in Dahl salt-sensitive rats.

The heptapeptide angiotensin-(1-7) (Ang-(1-7)) is protective in the cardiovascular system through its induction of vasodilator production and angiogenesis. Despite acting antagonistically to the effects of elevated, pathophysiological levels of angiotensin II (AngII), recent evidence has identified convergent and beneficial effects of low levels of both Ang-(1-7) and AngII. Previous work identified the AngII receptor type I (AT1R) as a component of the protein complex formed when Ang-(1-7) binds its receptor, Mas1. Importantly, pharmacological blockade of AT1R did not alter the effects of Ang-(1-7). Here, we use a novel mutation of AT1RA in the Dahl salt-sensitive (SS) rat to test the hypothesis that interaction between Mas1 and AT1R contributes to proangiogenic Ang-(1-7) signaling. In a model of hind limb angiogenesis induced by electrical stimulation, we find that the restoration of skeletal muscle angiogenesis in SS rats by Ang-(1-7) infusion is impaired in AT1RA knockout rats. Enhancement of endothelial cell (EC) tube formation capacity by Ang-(1-7) is similarly blunted in AT1RA mutant ECs. Transcriptional changes elicited by Ang-(1-7) in SS rat ECs are altered in AT1RA mutant ECs, and tandem mass spectrometry-based proteomics demonstrate that the protein complex formed upon binding of Ang-(1-7) to Mas1 is altered in AT1RA mutant ECs. Together, these data support the hypothesis that interaction between AT1R and Mas1 contributes to proangiogenic Ang-(1-7) signaling

Distinct biogeographic patterns for archaea, bacteria, and fungi along the vegetation gradient at the continental scale in Eastern China

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in mSystems 2 (2017): e00174-16, doi:10.1128/mSystems.00174-16.The natural forest ecosystem in Eastern China, from tropical forest to boreal forest, has declined due to cropland development during the last 300 years, yet little is known about the historical biogeographic patterns and driving processes for the major domains of microorganisms along this continental-scale natural vegetation gradient. We predicted the biogeographic patterns of soil archaeal, bacterial, and fungal communities across 110 natural forest sites along a transect across four vegetation zones in Eastern China. The distance decay relationships demonstrated the distinct biogeographic patterns of archaeal, bacterial, and fungal communities. While historical processes mainly influenced bacterial community variations, spatially autocorrelated environmental variables mainly influenced the fungal community. Archaea did not display a distance decay pattern along the vegetation gradient. Bacterial community diversity and structure were correlated with the ratio of acid oxalate-soluble Fe to free Fe oxides (Feo/Fed ratio). Fungal community diversity and structure were influenced by dissolved organic carbon (DOC) and free aluminum (Ald), respectively. The role of these environmental variables was confirmed by the correlations between dominant operational taxonomic units (OTUs) and edaphic variables. However, most of the dominant OTUs were not correlated with the major driving variables for the entire communities. These results demonstrate that soil archaea, bacteria, and fungi have different biogeographic patterns and driving processes along this continental-scale natural vegetation gradient, implying different community assembly mechanisms and ecological functions for archaea, bacteria, and fungi in soil ecosystems.This research was financially supported by the National Natural Science Foundation of China (grant number 41520104001), the 111 Project, and the Fundamental Research Funds for the Central Universities

PILER-CR: Fast and accurate identification of CRISPR repeats

BACKGROUND: Sequencing of prokaryotic genomes has recently revealed the presence of CRISPR elements: short, highly conserved repeats separated by unique sequences of similar length. The distinctive sequence signature of CRISPR repeats can be found using general-purpose repeat- or pattern-finding software tools. However, the output of such tools is not always ideal for studying these repeats, and significant effort is sometimes needed to build additional tools and perform manual analysis of the output. RESULTS: We present PILER-CR, a program specifically designed for the identification and analysis of CRISPR repeats. The program executes rapidly, completing a 5 Mb genome in around 5 seconds on a current desktop computer. We validate the algorithm by manual curation and by comparison with published surveys of these repeats, finding that PILER-CR has both high sensitivity and high specificity. We also present a catalogue of putative CRISPR repeats identified in a comprehensive analysis of 346 prokaryotic genomes. CONCLUSION: PILER-CR is a useful tool for rapid identification and classification of CRISPR repeats. The software is donated to the public domain. Source code and a Linux binary are freely available at