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C5F10Ohas recently been found to be a very promising alternative to SF6. This paper is devoted to the investigation of compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2. Firstly, the partition functions and enthalpies of formation for a few molecules (CxFy and CxFyO) which are likely to exist in the mixtures, are calculated based on the G4(MP2) theory. The isomers of the above molecules are selected according to their Gibbs energy. The compositions of C5F10O-CO2-O2 mixtures are then determined using the minimization of the Gibbs free energy. Next, the thermodynamic properties (mass density, specific enthalpy, and specific heat) are derived from the previously calculated compositions. Lastly, the transport coefficients (electrical conductivity, viscosity, and thermal conductivity) are calculated based on Chapman-Enskog method. It is found that, as an arc quenching gas,C5F10O could not recombine into itself with the temperature decreasing down to room temperature after the arc extinction. Besides, the key species at room temperature are always CF4, CO2, and C4F6 if graphite is not considered. When taken into account, graphite will replace C4F6 as one of the dominate particles. The mixing of CO2 with C5F10O plasma significantly affects the thermodynamic properties (e.g. vanishing and/or shifting of the peaks in specific heat) and transport coefficients (e.g. reducing viscosity and changing the number of peaks in thermal conductivity), while the addition of O2 with C5F10O-CO2 mixtures has no remarkable influence on both thermodynamic and transport properties. [ABSTRACT FROM AUTHOR]

The metallic vapours (i.e., copper, iron, and silver in this paper) resulting from walls and/or electrode surfaces can significantly affect the characteristics of air plasma. Different from the previous works assuming local thermodynamic equilibrium, this paper investigates the influence of metallic vapours on two-temperature (2 T) air plasma. The 2 T compositions of air contaminated by Cu, Fe, and Ag are first determined based on Saha's and Guldberg-Waage's laws. The thermodynamic properties (including mass density, specific enthalpy, and specific heat) are then calculated according to their definitions. After determining the collision integrals for each pair of species in air-metal mixtures using the newly published methods and source data, the transport coefficients (including electrical conductivity, viscosity, and thermal conductivity) are calculated for air-Cu, air-Fe, and air-Ag plasmas with different non-equilibrium degree θ (Te/Th). The influences of metallic contamination as well as non-equilibrium degree are discussed. It is found that copper, iron, and silver exist mainly in the form of Cu2, FeO, and AgO at low temperatures. Generally, the metallic vapours increase mass density at most temperatures, reduce the specific enthalpy and specific heat in the whole temperature range, and affect the transport properties remarkably from 5000K to 20 000 K. The effect arising from the type of metals is little except for silver at certain temperatures. Besides, the departure from thermal equilibrium results in the delay of dissociation and ionization reactions, leading to the shift of thermodynamic and transport properties towards a higher temperature. [ABSTRACT FROM AUTHOR]

Diffusion coefficients play an important role in the description of the transport of metal vapours in gas mixtures. This paper is devoted to the calculation of four combined diffusion coefficients, namely, the combined ordinary diffusion coefficient, combined electric field diffusion coefficient, combined temperature diffusion coefficient, and combined pressure diffusion coefficient in SF6-Cu mixtures at temperatures up to 30000 K. These four coefficients describe diffusion due to composition gradients, applied electric fields, temperature gradients, and pressure gradients, respectively. The influence of copper fluoride and sulfide species on the diffusion coefficients is shown to be negligible. The effect of copper proportion and gas pressures on these diffusion coefficients is investigated. It is shown that increasing the proportion of copper generally increases the magnitude of the four diffusion coefficients, except for copper mole fractions of 90% or more. It is further found that increasing the pressure reduces the magnitude of the coefficients, except for the combined temperature diffusion coefficient, and shifts the maximum of all four coefficients towards higher temperatures. The results presented in this paper can be applied to the simulation of high-voltage circuit breaker arcs. [ABSTRACT FROM AUTHOR]

Recently, much attention has been paid to SF6-CO2 mixtures as one of substitutes for pure SF6 gas. In this paper, the dielectric breakdown properties of hot SF6-CO2 mixtures are investigated at temperatures of 300-3500K and pressures of 0.01-1.0 MPa. Under the assumptions of local thermodynamic equilibrium and local chemical equilibrium, the equilibrium compositions of hot SF6-CO2 mixtures with different CO2 proportions are obtained based on Gibbs free energy minimization. The cross sections for interactions between electrons and neutral species are presented. Some unknown ionization cross sections are determined theoretically using Deutsch-Märk (DM) formalism based on quantum chemistry. Two-term Boltzmann equation is adopted to calculate the electron energy distribution function, reduced ionization coefficient, reduced attachment coefficient, and reduced effective ionization coefficient. Then the reduced critical electric field strength of mixtures, corresponding to dielectric breakdown performances, is determined when the generation and loss of electrons are balanced. Finally, the influences of temperature, pressure, and CO2 proportion on the reduced critical electric field strength are studied. It is found that a large percentage of CO2 can obviously reduce concentrations of high-energy electrons. At temperatures above 1750 K, an addition of CO2 to SF6 gas can enhance dielectric breakdown performances. However, at low temperatures, too much CO2 added into mixtures can reduce dielectric breakdown abilities. In addition, increasing gas pressure can improve dielectric breakdown performances. But the influence will be no more significant if pressure is over 0.8 MPa. [ABSTRACT FROM AUTHOR]

Objective: Several transient receptor potential (TRP) channels are expressed in pancreatic beta cells and have been proposed to be involved in insulin secretion. However, the endogenous ligands for these channels are far from clear. Here, we demonstrate the expression of the transient receptor potential ankyrin 1 (TRPA1) ion channel in the pancreatic beta cells and its role in insulin release. TRPA1 is an attractive candidate for inducing insulin release because it is calcium permeable and is activated by molecules that are produced during oxidative glycolysis. Methods: Immunohistochemistry, RT-PCR, and Western blot techniques were used to determine the expression of TRPA1 channel. Ca2+ fluorescence imaging and electrophysiology (voltage- and current-clamp) techniques were used to study the channel properties. TRPA1-mediated insulin release was determined using ELISA. Results: TRPA1 is abundantly expressed in a rat pancreatic beta cell line and freshly isolated rat pancreatic beta cells, but not in pancreatic alpha cells. Activation of TRPA1 by allyl isothiocyanate (AITC), hydrogen peroxide (H2O2), 4-hydroxynonenal (4- HNE), and cyclopentenone prostaglandins (PGJ2) and a novel agonist methylglyoxal (MG) induces membrane current, depolarization, and Ca2+ influx leading to generation of action potentials in a pancreatic beta cell line and primary cultured pancreatic beta cells. Activation of TRPA1 by agonists stimulates insulin release in pancreatic beta cells that can be inhibited by TRPA1 antagonists such as HC030031 or AP-18 and by RNA interference. TRPA1-mediated insulin release is also observed in conditions of voltage-gated Na+ and Ca2+ channel blockade as well as ATP sensitive potassium (KATP) channel activation. Conclusions: We propose that endogenous and exogenous ligands of TRPA1 cause Ca2+ influx and induce basal insulin release and that TRPA1-mediated depolarization acts synergistically with KATP channel blockade to facilitate insulin release. [ABSTRACT FROM AUTHOR]

Transient receptor potential (TRP) ankyrin 1 (TRPA1) is a Ca2+-permeant, nonselective cationic channel. It is predominantly expressed in the C afferent sensory nerve fibers of trigeminal and dorsal root ganglion neurons and is highly coexpressed with the nociceptive ion channel transient receptor potential vanilloid 1 (TRPV1). Several physical and chemical stimuli have been shown to activate the channel. In this study, we have used electrophysiological techniques and behavioral models to characterize the properties of TRPA1. Whole cell TRPA1 currents induced by brief application of lower concentrations of N-methyl maleimide (NMM) or allyl isothiocyanate (AITC) can be reversed readily by washout, whereas continuous application of higher concentrations of NMM or AITC completely desensitized the currents. The deactivation and desensitization kinetics differed between NMM and AITC. TRPA1 current amplitude increased with repeated application of lower concentrations of AITC, whereas saturating concentrations of AITC induced tachyphylaxis, which was more pronounced in the presence of extracellular Ca2+. The outward rectification exhibited by native TRPA1-mediated whole cell and single-channel currents was minimal as compared with other TRP channels. TRPA1 currents were negatively modulated by protons and polyamines, both of which activate the heat-sensitive channel, TRPV1. Interestingly, neither protein kinase C nor protein kinase A activation sensitized AITC-induced currents, but each profoundly sensitized capsaicin-induced currents. Current-clamp experiments revealed that AITC produced a slow and sustained depolarization as compared with capsaicin. TRPA1 is also expressed at the central terminals of nociceptors at the caudal spinal trigeminal nucleus. Activation of TRPA1 in this area increases the frequency and amplitude of miniature excitatory or inhibitory postsynaptic currents. In behavioral studies, intraplantar and intrathecal administration of AITC induced more pronounced and prolonged changes in nociceptive behavior than those induced by capsaicin. In conclusion, the characteristics of TRPA1 we have delineated suggest that it might play a unique role in nociception. [ABSTRACT FROM AUTHOR]

Composition of species is one of the key parameters in calculating the plasma properties and assessing the plasma chemical processes. Unlike the calculation of LTE plasma composition, the calculation of 2T plasma composition still remains in dispute. Different researchers have chosen different methods which lead to different results. In this work, we compare two kinds of methods for calculating 2T plasma composition: the mass action law methods and extremum searching methods. The former methods include the two described by Potapov and van de Sanden et al mass action laws, respectively. The latter methods include those of searching minimum Gibbs free energy and maximum entropy of a plasma system respectively. The entropy maximization method is first reported in this work and has the same power as the commonly used Gibbs free energy minimization method. We demonstrate both mathematically and numerically that the method of 2T Gibbs free minimization is completely the same as the 2T Potapov mass action law, and the method of 2T entropy maximization is exactly consistent with the 2T van de Sanden et al mass action law if we assume that the term μi/Ti is independent of the number density ni. It is also found that the assumption of number density-independent μi/Ti mainly affects the density of charged particles. When the plasma reaches the LTE state, the composition obtained by the methods of entropy maximization with and without this assumption will be exactly the same. [ABSTRACT FROM AUTHOR]

The assumption of gaseous species is not always valid in non-LTE plasmas. This requires the consideration of condensed phases in the determination of plasma composition. In this work, we compare two methods for calculating 2T multi-phase plasma composition: the Gibbs free energy minimization method and the entropy maximization method. The latter method is first reported in this work and has the same power as the former method for the calculation of 2T plasma composition taking into account condensed species. Based on these two methods, we present a case study of the multi-phase compositions of N2–Cu, CO2–Cu, and C2F4–Cu plasmas. It is found that the 2T entropy maximization method is less sensitive to the non-equilibrium degree than the 2T Gibbs free energy minimization method. This leads to the large difference between the composition predicted by the two methods, for example, in the phase transition temperature. The case study shows that due to the high electron temperature at large non-equilibrium degree, the ionic species (e.g. Cu+ and C+) can be generated directly from the condensed species (e.g CuF2, Cu2O, Cu, and C). Such ionization does not occur if the copper proportion is very low (e.g only 1%). [ABSTRACT FROM AUTHOR]

Plants have evolved sophisticated mechanisms to regulate gene expression to activate immune responses against pathogen infections. However, how the translation system contributes to plant immunity is largely unknown. The evolutionarily conserved thiolation modification of transfer RNA (tRNA) ensures efficient decoding during translation. Here, we show that tRNA thiolation is required for plant immunity in Arabidopsis. We identify a cgb mutant that is hyper-susceptible to the pathogen Pseudomonas syringae. CGB encodes ROL5, a homolog of yeast NCS6 required for tRNA thiolation. ROL5 physically interacts with CTU2, a homolog of yeast NCS2. Mutations in either ROL5 or CTU2 result in loss of tRNA thiolation. Further analyses reveal that both transcriptome and proteome reprogramming during immune responses are compromised in cgb. Notably, the translation of salicylic acid receptor NPR1 is reduced in cgb, resulting in compromised salicylic acid signaling. Our study not only reveals a regulatory mechanism for plant immunity but also uncovers an additional biological function of tRNA thiolation. [ABSTRACT FROM AUTHOR]

Perfluoroketone (PFK) gases are widely used in industry, e.g. as an insulating medium in high-voltage apparatus and as a cleaning agent in chemical vapor deposition (CVD) chambers. A great deal of attention has been paid to them recently because of their low global warming potential (GWP). In order to describe the ionization processes in various plasmas resulting from PFK gases, the electron-impact ionization cross sections (Qion) of PFK molecules CxF2xO (x = 1–5) were calculated by the Binary-Encounter Bethe (BEB) and the Deutsch-Märk (DM) methods. The chemical structures of PFK molecules were optimized by the hybrid Density Functional Theory (DFT) method with the Austin-Petersson-Frisch functional including dispersion (APF-D). The binding and kinetic energies of electrons in molecular orbitals were also determined with the APF-D hybrid DFT method. The binding energies of valence electrons were then improved by the electron propagator theory (EPT) method. The ionization potentials of PFK molecules were calculated as the difference between the energy of a molecule and its cation using the complete basis set (CBS) method. The molecular orbital compositions were obtained by the natural atomic orbital (NAO) analysis. The results show that Qion determined by the BEB method are always larger than those by the DM method. The difference is reduced with the EPT corrections considered. The comparison between the theoretical and experimental Qion demonstrates that the EPT correction improves Qion considerably. [ABSTRACT FROM AUTHOR]

Petal senescence is controlled by a complex regulatory network. Epigenetic regulation like histone modification influences chromatin state and gene expression. However, the involvement of histone methylation in regulating petal senescence remains poorly understood. Here, we found that the trimethylation of histone H3 at Lysine 4 (H3K4me3) is increased during ethylene-induced petal senescence in carnation (Dianthus caryophyllus L.). H3K4me3 levels were positively associated with the expression of transcription factor DcWRKY75, ethylene biosynthetic genes 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (DcACS1), and ACC oxidase (DcACO1), and senescence associated genes (SAGs) DcSAG12 and DcSAG29. Further, we identified that carnation ARABIDOPSIS HOMOLOG OF TRITHORAX1 (DcATX1) encodes a histone lysine methyltransferase which can methylate H3K4. Knockdown of DcATX1 delayed ethylene-induced petal senescence in carnation, which was associated with the down-regulated expression of DcWRKY75, DcACO1, and DcSAG12, whereas overexpression of DcATX1 exhibited the opposite effects. DcATX1 promoted the transcription of DcWRKY75, DcACO1, and DcSAG12 by elevating the H3K4me3 levels within their promoters. Overall, our results demonstrate that DcATX1 is a H3K4 methyltransferase that promotes the expression of DcWRKY75, DcACO1, DcSAG12 and potentially other downstream target genes by regulating H3K4me3 levels, thereby accelerating ethylene-induced petal senescence in carnation. This study further indicates that epigenetic regulation is important for plant senescence processes. [ABSTRACT FROM AUTHOR]

The dielectric breakdown properties of hot SF6 gas during the dielectric recovery phase play an important role in understanding gas breakdown occurring in high-voltage circuit breakers. This paper is devoted to the theoretical investigation of dielectric breakdown properties of hot SF6 gas contaminated by copper at temperatures of 300–3500 K and pressures of 0.01–1.6 MPa. The equilibrium compositions of SF6–Cu mixtures are obtained with the consideration of condensed species. The unknown ionization cross sections for CuS, CuF and CuF2 are calculated using a Deutsch–Märk (DM) formalism based on quantum chemistry. The two-term Boltzmann equation is adopted to numerically calculate the electron energy distribution function, collision ionization coefficient and electron attachment coefficient. Then the reduced critical electric field strength is determined when the effective ionization coefficient equals to zero. The influences of the Cu proportion and gas pressure on the dielectric breakdown properties are investigated. It is shown that the existence of copper compounds increases the concentration of high-energy electrons significantly, even for the case with a very low percentage (e.g. 1% Cu). With the increase of copper content, the value of (E/N)cr is reduced remarkably at temperatures below 3000 K, but enhanced slightly above 3000 K. It is also found that the increase of pressure can improve the dielectric breakdown performance of hot SF6–Cu mixtures. [ABSTRACT FROM AUTHOR]

The equilibrium compositions and thermodynamic properties of SF6–Cu mixtures with copper proportions up to 50% are calculated as a function of temperature from 300 to 30 000 K and pressure from 0.01 to 1.0 MPa. The condensed phases and Debye–Hückel corrections are both taken into account. The influences of condensed phases, Debye–Hückel corrections, copper proportions and gas pressures on the composition and/or thermodynamic properties are discussed in detail under various conditions. Some results are tabulated for the modelling of SF6 arc plasmas contaminated by Cu. [ABSTRACT FROM AUTHOR]

The transport coefficients (including electrical conductivity, viscosity and thermal conductivity) of SF6-Cu mixtures with copper proportions up to 50% are calculated as a function of temperature from 300 to 30,000 K and pressure from 0.01 to 1.0 MPa. The Lennard–Jones like phenomenological potential and some recently updated transport cross sections are adopted to obtain collision integrals. The influence of copper proportion and gas pressure on transport coefficients under various conditions are discussed in detail. Some results are tabulated for the modeling of SF6 arc plasmas contaminated by Cu. [ABSTRACT FROM AUTHOR]

Nucleic acid-based diagnostics are widely used for clinical applications due to their powerful recognition of biomolecule properties. Isolation and purification of nucleic acids such as DNA and RNA in the diagnostic system have been severely hampered in point-of-care testing because of low recovery yields, degradation of nucleic acids due to the use of chaotropic detergent and high temperature, and the requirement of large instruments such as centrifuges and thermal controllers. Here, we report a novel large instrument- and detergent-free assay via binary nanomaterial for ultrasensitive nucleic acid isolation and detection from cells (eukaryotic and prokaryotic). This binary nanomaterial couples a zinc oxide nanomultigonal shuttle (ZnO NMS) for cell membrane rupture without detergent and temperature control and diatomaceous earth with dimethyl suberimidate complex (DDS) for the capture and isolation of nucleic acids (NA) from cells. The ZnO NMS was synthesized to a size of 500 nm to permit efficient cell lysis at room temperature within 2 min using the biological, chemical, and physical properties of the nanomaterial. By combining the ZnO NMS with the DDS and proteinase K, the nucleic acid extraction could be completed in 15 min with high quantity and quality. For bacterial cells, DNA isolation with the binary nanomaterial yielded 100 times more DNA, than a commercial spin column based reference kit, as determined by the NanoDrop spectrophotometer. We believe that this binary nanomaterial will be a useful tool for rapid and sensitive nucleic acid isolation and detection without large instruments and detergent in the field of molecular diagnostics. [ABSTRACT FROM AUTHOR]

RNA editing is a posttranscriptional process that covalently alters the sequence of RNA molecules and plays important biological roles in both animals and land plants. In flowering plants, RNA editing converts specific cytidine residues to uridine in both plastid and mitochondrial transcripts. Previous studies identified pentatricopeptide repeat (PPR) motif-containing proteins as site-specific recognition factors for cytidine targets in RNA sequences. However, the regulatory mechanism underlying RNA editing was largely unknown. Here, we report that protoporphyrinogen IX oxidase 1 (PPO1), an enzyme that catalyzes protoporphyrinogen IX into protoporphyrin IX in the tetrapyrrole biosynthetic pathway, plays an unexpected role in editing multiple sites of plastid RNA transcripts, most of which encode subunits of the NADH dehydrogenase-like complex (NDH), in the reference plant Arabidopsis thaliana. We identified multiple organellar RNA editing factors (MORFs), including MORF2, MORF8, and MORF9, that interact with PPO1. We found that two conserved motifs within the 22-aa region at the N terminus of PPO1 are essential for its interaction with MORFs, its RNA editing function, and subsequently, its effect on NDH activity. However, transgenic plants lacking key domains for the tetrapyrrole biosynthetic activity of PPO1 exhibit normal RNA editing. Furthermore, MORF2 and MORF9 interact with three PPRs or related proteins required for editing of ndhB and ndhD sites. These results reveal that the tetrapyrrole biosynthetic enzyme PPO1 is required for plastid RNA editing, acting as a regulator that promotes the stability of MORF proteins through physical interaction. [ABSTRACT FROM AUTHOR]

This paper is devoted to the calculation of fundamental properties of CO2 mixed with C2F4. The species composition and thermodynamic properties (mass density, entropy, enthalpy and specific heat at constant pressure) are based on Gibbs free energy minimization. The transport properties (electrical conductivity, viscosity and thermal conductivity) are calculated by the well-known Chapman-Enskog method. The Lennard-Jones like phenomenological potential and some recently updated transport cross sections are adopted to obtain collision integrals. The calculation is developed in the temperature range between 300 and 30 000 K, for a pressure between 1 to 16 bar and for several C2F4 proportions. Transport coefficients for CO2 are also compared with previous published values, and the reasons for discrepancies are analyzed. The results obtained for CO2–C2F4 mixtures provide reliable reference data for the simulation of switching arcs in CO2 circuit breakers with the ablation of PTFE. [ABSTRACT FROM AUTHOR]