151 research outputs found

    A Novel Detection Scheme for EBPSK System

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    We introduce the extended binary phase shift keying (EBPSK) communication system which is different from traditional communication systems by using a special impacting filter (SIF) for demodulation. The joint detection technique is applied at the demodulator side in order to improve the performance of the system under intersymbol interference (ISI). The main advantage of the joint detection technique, when compared to conventional threshold approaches, lies in its ability to use the amplitude and the correlation between neighboring bits, thus significantly improving performance, with low complexity. Moreover, we concentrate not only on increasing the bit rate of the system, but also on designing a bandwidth efficient communication system. Simulation results show that this new approach significantly outperforms the conventional method of using threshold decision by from 3.5 to 5 dB. The new system also occupies a narrower bandwidth. So joint detection is an effective method for EBPSK demodulation under ISI

    Coherence and complementarity based on modified generalized skew information

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    We introduce modified generalized Wigner-Yanase-Dyson (MGWYD) skew information and modified weighted generalized Wigner-Yanase-Dyson (MWGWYD) skew information. By revisiting state-channel interaction based on MGWYD skew information, a family of coherence measures with respect to quantum channels is proposed. Furthermore, explicit analytical expressions of these coherence measures of qubit states are derived with respect to different quantum channels. Moreover, complementarity relations based on MGWYD skew information and MWGWYD skew information are also presented. Specifically, the conservation relations are investigated, while two interpretations of them including symmetry-asymmetry complementarity and wave-particle duality have been proposed.Comment: 20page

    Average skew information-based coherence and its typicality for random quantum states

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    We study the average skew information-based coherence for both random pure and mixed states. The explicit formulae of the average skew information-based coherence are derived and shown to be the functions of the dimension N of the state space. We demonstrate that as N approaches to infinity, the average coherence is 1 for random pure states, and a positive constant less than 1/2 for random mixed states. We also explore the typicality of average skew information-based coherence of random quantum states. Furthermore, we identify a coherent subspace such that the amount of the skew information-based coherence for each pure state in this subspace can be bounded from below almost always by a fixed number that is arbitrarily close to the typical value of coherence.Comment: 24page

    Uncertainty Relations Based on Modified Wigner-Yanase-Dyson Skew Information

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    Uncertainty relation is a core issue in quantum mechanics and quantum information theory. We introduce modified generalized Wigner-Yanase-Dyson (MGWYD) skew information and modified weighted generalizedWigner-Yanase-Dyson (MWGWYD) skew information, and establish new uncertainty relations in terms of the MGWYD skew information and MWGWYD skew information.Comment: 16 page

    Quantitative analysis of the risk of hydrogen sulfide release from gas hydrates

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    The role that H2S plays in the global sulfur cycle has been studied extensively in recent years. This paper focuses on the influence of H2S released from gas hydrates on sulfur cycle and establishes a one-dimensional mathematical model to calculate the amount of H2S released from the dissociation of gas hydrates present in multiple layers in the Qiongdongnan Basin China. The results show that the sulfate and methane transition zone that covers an area of about 100 km2in the Qiongdongnan Basin contains 2.3 × 1012 g of pyrite, which requires 4.06 × 1011 mol of H2S for its formation. The H2S released from the dissociation of gas hydrates is 5.4 ×1011 mol, which is about 1.3 times that needed for the formation of pyrite. Therefore, the H2S released from the gas hydrates is an important source of H2S for the formation of pyrite in the sulfate-methane transition zone of Qiongdongnan Basin. According to the flux of H2S and the partial pressure of O2 (PO2) in the atmosphere, the critical value of the balance between the flux of H2S and PO2 turns out to be 0.13 mol kg−1∙bar−1. Furthermore, considering the effect of global sea-level changes, three risk modes are identified to categorize the amount of H2S released from the dissociation of gas hydrate into the atmosphere. We classify the periods from 5–12 Ma BP, 25–29 Ma BP, 47–52 Ma, and 57–61 Ma BP into the high-risk mode. Furthermore, the results show that a part of the H2S released from the gas hydrate dissociation is oxidized by the Fe (III) oxide metal, with much of the metal ions being released into the pore water. Another part of the H2S is re-oxidized by the O2 in the ocean, with much of SO42- released into the seawater. Therefore, the process also provides metal ions and SO42- to pore water or seawater when the H2S released from gas hydrate diffuses from the bottom. This paper provides new insights into the source of H2S in the ocean and shows that the H2S contained in gas hydrates plays an important role in the global sulfur cycle

    Enhanced Gene Transfection Efficacy and Safety Through Granular Hydrogel Mediated Gene Delivery Process

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    Although gene therapy has made great achievements in both laboratory research and clinical translation, there are still challenges such as limited control of drug pharmacokinetics, acute toxicity, poor tissue retention, insufficient efficacy, and inconsistent clinical translation. Herein, a gene therapy gel is formulated by directly redispersing polyplex nanoparticles into granular hydrogels without any gelation pre-treatment, which provides great convenience for storage, dosing and administration. In vitro studies have shown that use of granular hydrogels can regulate the gene drug release, reduce dose dependent toxicity and help improve transfection efficacy. Moreover, the developed gene therapy gel is easy to operate and can be directly used in vitro to evaluate its synergistic efficacy with various gene delivery systems. As such, it represents a major advance over many conventional excipient-based formulations, and new regulatory strategies for gene therapy may be inspired by it

    N-Oxide Reduction of Quinoxaline-1,4-Dioxides Catalyzed by

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    ABSTRACT Quinoxaline-1,4-dioxides (QdNOs) are a class of quinoxaline derivatives that are widely used in humans or animals as drugs or feed additives. However, the metabolic mechanism, especially the involved enzymes, has not been reported in detail. In this study, the N-oxide reduction enzyme, porcine aldehyde oxidase SsAOX1 was identified and characterized. The SsAOX1 gene was cloned from pig liver through reverse-transcription polymerase chain reaction using degenerate primers, which encode a 147-kDa protein with typical aldehyde oxidase motifs, two [2Fe-2S] centers, a flavin adenine dinucleotide (FAD) binding domain, and a molybdenum cofactor domain. After heterologous expression in a prokaryote, purified SsAOX1 formed a functional homodimer under native conditions. Importantly, the SsAOX1 catalyzed the N-oxide reduction at the N1 position of three representative QdNOs (quinocetone, mequindox, and cyadox), which are commonly used as animal feed additives. SsAOX1 has the highest activity toward quinocetone, followed by mequindox and cyadox, with kcat/K m values of 1.94 6 0.04, 1.27 6 0.15, and 0.43 6 0.09 minute 21 mM 21 , respectively. However, SsAOX1 has the lowest substrate affinity for quinocetone, followed by the cyadox and mequindox, with K m values of 4.36 6 0.56, 3.16 6 0.48, and 2.96 6 0.51 mM, respectively. In addition, using site-directed mutagenesis, we found that substitution of glycine 1019 with threonine endows SsAOX1 with N-oxide reductive activity at the N4 position. The goal of this study was to identify and characterize the N-oxide reduction enzyme for a class of veterinary drugs, QdNOs, which will aid in the elucidation of the metabolic pathways of QdNOs and will provide a theoretical basis for their administration and new veterinary drug design

    Transcriptional Activation of Pyoluteorin Operon Mediated by the LysR-Type Regulator PltR Bound at a 22 bp lys Box in Pseudomonas aeruginosa M18

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    Pseudomonas aeruginosa M18, a rhizosphere-isolated bacterial strain showing strong antifungal activity, can produce secondary metabolites such as phenazine-1-carboxylic acid and pyoluteorin (Plt). The LysR-type transcriptional regulator PltR activates the Plt biosynthesis operon pltLABCDEFG, the expression of which is induced by Plt. Here, we identified and characterized the non-conserved pltL promoter (pltLp) specifically activated by PltR and its upstream neighboring lys box from the complicated pltR–pltL intergenic sequence. The 22 bp palindromic lys box, which consists of two 9 bp complementary inverted repeats interrupted by 4 bp, was found to contain the conserved, GC-rich LysR-binding motif (T-N11-A). Evidence obtained in vivo from mutational and lacZ report analyses and in vitro from electrophoretic mobility shift assays reveals that the PltR protein directly bound to the pltLp region as the indispensable binding motif “lys box”, thereby transcriptionally activating the pltLp-driven plt operon expression. Plt, as a potential non-essential coinducer of PltR, specifically induced the pltLp expression and thus strengthened its biosynthetic plt operon expression

    Regulatory Feedback Loop of Two phz Gene Clusters through 5′-Untranslated Regions in Pseudomonas sp. M18

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    BACKGROUND: Phenazines are important compounds produced by pseudomonads and other bacteria. Two phz gene clusters called phzA1-G1 and phzA2-G2, respectively, were found in the genome of Pseudomonas sp. M18, an effective biocontrol agent, which is highly homologous to the opportunistic human pathogen P. aeruginosa PAO1, however little is known about the correlation between the expressions of two phz gene clusters. METHODOLOGY/PRINCIPAL FINDINGS: Two chromosomal insertion inactivated mutants for the two gene clusters were constructed respectively and the correlation between the expressions of two phz gene clusters was investigated in strain M18. Phenazine-1-carboxylic acid (PCA) molecules produced from phzA2-G2 gene cluster are able to auto-regulate expression itself and activate the expression of phzA1-G1 gene cluster in a circulated amplification pattern. However, the post-transcriptional expression of phzA1-G1 transcript was blocked principally through 5'-untranslated region (UTR). In contrast, the phzA2-G2 gene cluster was transcribed to a lesser extent and translated efficiently and was negatively regulated by the GacA signal transduction pathway, mainly at a post-transcriptional level. CONCLUSIONS/SIGNIFICANCE: A single molecule, PCA, produced in different quantities by the two phz gene clusters acted as the functional mediator and the two phz gene clusters developed a specific regulatory mechanism which acts through 5'-UTR to transfer a single, but complex bacterial signaling event in Pseudomonas sp. strain M18
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