3,204 research outputs found

    Defense responses in tomato fruit induced by oligandrin against Botrytis cinerea

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    Oligandrin is known to induce resistance against a number of plant diseases. However, its effects on postharvest diseases are still unclear. The effects of oligandrin on the control of postharvest diseases in tomato fruit and its underlying mechanisms were investigated in this study. The treat01ent of tomato fruit with oligandrin (10 μg/ml) significantly reduced the incidence and severity of gray mould (caused by Botrytis cinerea). After 5, 7 and 9 days of artificial inoculation, the relative cure effect was 60.5, 52.1 and 48.5%, respectively. The results from bio-assay indicated that the treatment stimulated the activity of the defense related enzymes. Phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) activity in the oligandrin-treated fruit was about 39.2, 69.6 and 52.6% higher than that in control on the 3rd day, respectively. Furthermore, mRNA level of the genes encoding pathogenesis-related proteins (PRs), such as PR-2a (extracellular β-1, 3 -glucanase) and PR-3a (extracellular chitinase) in tomato fruit was about 2.7-fold and 4.6-fold above that of the control at the peak stage. The expression of LeERF2 and PR6, which confer an ethylene-dependent signaling pathway, were also significantly increased 6.6-fold and 3.6-fold by such treatment. These results indicate that oligandrin has the potential to control gray mould and it may play an important role in the induction of resistance to B. cinerea and the activation of the ethylene-dependent signaling pathway.Key words: Tomato, disease resistance, oligandrin, Botrytis cinerea

    Enhancement of defense responses by oligandrin against Botrytis cinerea

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    Oligandrin is an elicitin-like protein with a molecular mass of ∼10 kDa secreted by Pythium oligandrum. Here, the effect of oligandrin on defense response against Botrytis cinerea in tomato leaves is reported. Tomato seedlings were pretreated with 5 ml oligandrin (10 g/ml) by root submerging and then inoculated with B. cinerea. Disease severity was subsequently evaluated and compared with the control. Results indicate that oligandrin pretreatment reduced disease index by 78.6% on day 7 after inoculation. On day 3 after inoculation, oligandrin pretreatment caused up-regulation of peroxidases (POD), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) in leaves by 20.0, 5.56 and 32.88%, compared with inoculation without oligandrin pretreatment, respectively. On day 5 after inoculation, POD, PPO and PAL were up-regulated by 46.24, 32.61 and 57.14%, respectively. 24 h after the treatment with oligandrin, the expression of pathogenesis-related protein (PRs) genes, PR-2a (extracellular β-1,3-glucanase) and PR-3a (extracellular chitinase), were up-regulated by 7.75 fold and 4.56 fold in tomato leaves, compared with the control, respectively. The expression of LeERF2, a member of ethylene-dependent signaling pathway, was also significantly elevated by 7.41 fold. At the same time, the expression of ethylene receptor homologue PR-6 protein was also induced. These results indicate that oligandrin can induce resistance to B. cinerea in tomatoes, and the induction of resistance involves the activation of the ethylene-dependent signaling pathway. Oligandrin is potentially useful for gray mould prevention in tomato crop.Key words: Botrytis cinerea, induced resistance, oligandrin, resistance related enzymes

    Performance analysis of dense small cell networks with dynamic TDD

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    © 1967-2012 IEEE. Small cell networks (SCNs) are envisioned to embrace dynamic time division duplexing (TDD) in order to tailor downlink (DL)/uplink (UL) subframe resources to quick variations and burstiness of DL/UL traffic. The study of dynamic TDD is particularly important because it serves as the predecessor of the full duplex transmission technology, which has been identified as one of the candidate technologies for the 5th-generation (5G) networks. In this paper, we study the performance of the synchronous dynamic TDD from a media access control layer viewpoint, which has been widely adopted in the existing 4G systems. Furthermore, we analyze the coverage probability and the area spectral efficiency in the DL and UL of dense SCNs considering the synchronous dynamic TDD transmissions, and the performance impact of dynamic TDD transmissions on the ASE in the DL and UL of dense SCNs is discussed. Moreover, the performance impact of interference cancellation is also explored. Our analytical results shed new light on the performance of dynamic TDD in future synchronous 5G networks

    Uplink Performance Analysis of Dense Cellular Networks with LoS and NLoS Transmissions

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    © 2002-2012 IEEE. In this paper, we analyze the coverage probability and the area spectral efficiency (ASE) for the uplink (UL) of dense small cell networks (SCNs) considering a practical path loss model incorporating both line-of-sight (LoS) and non-line-of-sight (NLoS) transmissions. Compared with the existing work, we adopt the following novel approaches in this paper: 1) we assume a practical user association strategy (UAS) based on the smallest path loss, or equivalently the strongest received signal strength; 2) we model the positions of both base stations (BSs) and the user equipments (UEs) as two independent homogeneous Poisson point processes; and 3) the correlation of BSs' and UEs' positions is considered, thus making our analytical results more accurate. The performance impact of LoS and NLoS transmissions on the ASE for the UL of dense SCNs is shown to be significant, both quantitatively and qualitatively, compared with existing work that does not differentiate LoS and NLoS transmissions. In particular, existing work predicted that a larger UL power compensation factor would always result in a better ASE in the practical range of BS density, i.e., 10-1∼ 10-3 BSs/km2. However, our results show that a smaller UL power compensation factor can greatly boost the ASE in the UL of dense SCNs, i.e., 10-2∼ 10-3 BSs/km2 , while a larger UL power compensation factor is more suitable for sparse SCNs, i.e., 10-1∼ 10-2,BSs/km-2

    Escort Evolutionary Game Theory

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    A family of replicator-like dynamics, called the escort replicator equation, is constructed using information-geometric concepts and generalized information entropies and diverenges from statistical thermodynamics. Lyapunov functions and escort generalizations of basic concepts and constructions in evolutionary game theory are given, such as an escorted Fisher's Fundamental theorem and generalizations of the Shahshahani geometry.Comment: Minor typo correctio

    Sequence Variations of Full-Length Hepatitis B Virus Genomes in Chinese Patients with HBsAg-Negative Hepatitis B Infection

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    BACKGROUND: The underlying mechanism of HBsAg-negative hepatitis B virus (HBV) infection is notoriously difficult to elucidate because of the extremely low DNA levels which define the condition. We used a highly efficient amplification method to overcome this obstacle and achieved our aim which was to identify specific mutations or sequence variations associated with this entity. METHODS: A total of 185 sera and 60 liver biopsies from HBsAg-negative, HBV DNA-positive subjects or known chronic hepatitis B (CHB) subjects with HBsAg seroclearance were amplified by rolling circle amplification followed by full-length HBV genome sequencing. Eleven HBsAg-positive CHB subjects were included as controls. The effects of pivotal mutations identified on regulatory regions on promoter activities were analyzed. RESULTS: 22 and 11 full-length HBV genomes were amplified from HBsAg-negative and control subjects respectively. HBV genotype C was the dominant strain. A higher mutation frequency was observed in HBsAg-negative subjects than controls, irrespective of genotype. The nucleotide diversity over the entire HBV genome was significantly higher in HBsAg-negative subjects compared with controls (p = 0.008) and compared with 49 reference sequences from CHB patients (p = 0.025). In addition, HBsAg-negative subjects had significantly higher amino acid substitutions in the four viral genes than controls (all p<0.001). Many mutations were uniquely found in HBsAg-negative subjects, including deletions in promoter regions (13.6%), abolishment of pre-S2/S start codon (18.2%), disruption of pre-S2/S mRNA splicing site (4.5%), nucleotide duplications (9.1%), and missense mutations in "alpha" determinant region, contributing to defects in HBsAg production. CONCLUSIONS: These data suggest an accumulation of multiple mutations constraining viral transcriptional activities contribute to HBsAg-negativity in HBV infection.published_or_final_versio

    catena-Poly[[silver(I)-μ-1,2-bis­(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)ethane-κ2 N:N′] perchlorate hemihydrate]

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    In the title coordination polymer, {[Ag(C12H20N2O2)]ClO4·0.5H2O}n, the AgI cation is coordinated by two N atoms from two 1,2-bis­(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)ethane (L) ligands in a nearly linear geometry [N—Ag—N = 171.07 (8)°]. The L ligand bridges adjacent Ag+ cations, forming a polymeric chain running along the c axis. The lattice water mol­ecule is situated on a twofold rotation axis, and links to the perchlorate anion via an O—H⋯O hydrogen bond. The long Ag⋯O separation of 3.200 (4) Å indicates a weak inter­action between the perchlorate anion and the AgI cation. Weak C—H⋯O hydrogen bonding occurs between the chain and the lattice water mol­ecule and between the chain and perchlorate anions. Both five-membered rings of the L ligand display envelope conformations; in one five-membered ring, the flap C atom is disordered on opposite sides of the ring with occupancies of 0.65 and 0.35

    Sensor Fabrication Method for in Situ Temperature and Humidity Monitoring of Light Emitting Diodes

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    In this work micro temperature and humidity sensors are fabricated to measure the junction temperature and humidity of light emitting diodes (LED). The junction temperature is frequently measured using thermal resistance measurement technology. The weakness of this method is that the timing of data capture is not regulated by any standard. This investigation develops a device that can stably and continually measure temperature and humidity. The device is light-weight and can monitor junction temperature and humidity in real time. Using micro-electro-mechanical systems (MEMS), this study minimizes the size of the micro temperature and humidity sensors, which are constructed on a stainless steel foil substrate (40 μm-thick SS-304). The micro temperature and humidity sensors can be fixed between the LED chip and frame. The sensitivities of the micro temperature and humidity sensors are 0.06 ± 0.005 (Ω/°C) and 0.033 pF/%RH, respectively

    Introduction to Khovanov Homologies. I. Unreduced Jones superpolynomial

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    An elementary introduction to Khovanov construction of superpolynomials. Despite its technical complexity, this method remains the only source of a definition of superpolynomials from the first principles and therefore is important for development and testing of alternative approaches. In this first part of the review series we concentrate on the most transparent and unambiguous part of the story: the unreduced Jones superpolynomials in the fundamental representation and consider the 2-strand braids as the main example. Already for the 5_1 knot the unreduced superpolynomial contains more items than the ordinary Jones.Comment: 33 page

    Anomalous dependence of the c-axis polarized Fe B1g_{1g} phonon mode with Fe and Se concentrations in Fe1+y_{1+y}Te1−x_{1-x}Sex_x

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    We report an investigation of the lattice dynamical properties in a range of Fe1+y_{1+y}Te1−x_{1-x}Sex_{x} compounds, with special emphasis on the c-axis polarized vibration of Fe with B1g_{1g} symmetry, a Raman active mode common to all families of Fe-based superconductors. We have carried out a systematic study of the temperature dependence of this phonon mode as a function of Se xx and excess Fe yy concentrations. In parent compound Fe1+y_{1+y}Te, we observe an unconventional broadening of the phonon between room temperature and magnetic ordering temperature TNT_N. The situation smoothly evolves towards a regular anharmonic behavior as Te is substituted for Se and long range magnetic order is replaced by superconductivity. Irrespective to Se contents, excess Fe is shown to provide an additional damping channel for the B1g_{1g} phonon at low temperatures. We performed Density Functional Theory (DFT) ab-initio calculations within the local density approximation (LDA) to calcuate the phonon frequencies including magnetic polarization and Fe non-stoichiometry in the Virtual Crystal Approximation (VCA). We obtained a good agreement with the measured phonon frequencies in the Fe-deficient samples, while the effects of Fe excess are poorly reproduced. This may be due to excess Fe-induced local magnetism and low energy magnetic fluctuations that can not be treated accurately within these approaches. As recently revealed by neutron scattering and μ\mu-SR studies, these phenomena occur in the temperature range where anomalous decay of the B1g_{1g} phonon is observed, and suggests a peculiar coupling of this mode with local moments and spin fluctuations in Fe1+y_{1+y}Te1−x_{1-x}Sex_{x}
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