111 research outputs found

    Energy of the quasi-free electron in argon, krypton and xenon

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    Abstract Recent field ionization measurements of various high-n molecular Rydberg states doped into argon, krypton and xenon perturbers are presented as a function of perturber number density up to the density of the triple point liquid. These data are modeled to within ±0.3% of experiment on both critical and noncritical isotherms using a new theoretical treatment that includes: (i) the polarization of the perturber by the dopant cation, (ii) the polarization of the perturber by the quasi-free electron that arises from field ionization of the dopant, and (iii) the kinetic energy of the quasi-free electron. The polarization terms are determined by a standard statistical mechanical treatment. However, the kinetic energy of the quasi-free electron is calculated within a new local Wigner-Seitz model that contains only one adjustable parameter. This treatment provides an accurate model of the energy of the bottom of the conduction band (V 0 ) in argon, krypton and xenon from the dilute gas up to the density of the triple point liquid, on both critical and noncritical isotherms. The use of supercritical fluids in environmental remediation, in the treatment of high-level hazardous wastes and in tailoring chemical reactions for specific product yields necessitates a better understanding of density and temperature effects on the properties of neutral and charged species solvated in these fluids. We have recently studied the perturber induced shift ∆ D (ρ P ) of dopant ionization energyand the quasi-free electron energy V 0 (ρ P ) -in the rare gases Ar [1-3], Kr Experimental information on the dopants and perturbers used in these studies and the procedures used to ensure homogeneous mixing of samples in the gas handling system have been described previously The quasi-free electron energy V 0 (ρ P ) in a dense perturbing gas can be extracted from ∆ D (ρ P ), which is determined from field ionization studies, using [1-5] where P + (ρ P ) is the ensemble average dopant ionic core/perturber polarization energy, and ρ P is the perturber number density. P + (ρ P ) is calculated from a standard statistical mechanical treatment via [1-5] In eq. (2) g PD (r) is the perturber/dopant radial distribution function, and w + (r) is the perturber/ion interaction potentia

    Xenon low-n Rydberg states in supercritical argon near the critical point

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    Abstract We present vacuum ultraviolet absorption spectra and an asymmetric line shape simulation of the 6s and 6s Rydberg states (including the blue satellite bands) of xenon doped into argon, from low argon number density to the density of the triple point liquid, at both noncritical temperatures and near (+0.5 • C) the critical isotherm of argon (i.e., −122.3 • C). The argon induced shift in the simulated primary transition of the Xe 6s and 6s Rydberg states is presented as a function of argon number density for noncritical temperatures and along an isotherm near the critical temperature. This shift demonstrates a perturber critical point effect on the transition energies of low-n dopant Rydberg states

    Variations in growth traits and wood physicochemical properties among Pinus koraiensis families in Northeast China

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    This study aimed to explore and improve the different economic values of Pinus koraiensis (Siebold and Zucc.) by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P. koraiensis half-sib families. Growth traits assessed included height, diameter at breast height, volume, degree of stem straightness, stem form, and branch number per node, while wood properties assessed included density, fiber length and width, fiber length to width ratio, and cellulose, hemicellulose, holocellulose, lignin, and ash contents. Except for degree of stem straightness and branch number per node, all other traits exhibited highly significant variations (P < 0.01) among families. The coefficients of variation ranged from 5.3 (stem form) to 66.7% (ash content), whereas, the heritability ranged from 0.136 (degree of stem straightness) to 0.962 (ash content). Significant correlations were observed among growth traits and wood physicochemical properties. Principal component analysis identified four distinct groups representing growth traits, wood chemical and physical properties, and stem form traits. Multi-trait comprehensive evaluation identified three groups of elite families based on breeding objectives, including rapid growth, improved timber production for building and furniture materials, and pulpwood production. These specific families should be used to establish new plantations

    A hierarchical approach for modelling X-ray beamlines. Application to a coherent beamline

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    We consider different approaches to simulate a modern X-ray beamline. Several methodologies with increasing complexity are applied to discuss the relevant parameters that quantify the beamline performance. Parameters such as flux, dimensions and intensity distribution of the focused beam and coherence properties are obtained from simple analytical calculations to sophisticated computer simulations using ray-tracing and wave optics techniques. A latest-generation X-ray nanofocusing beamline for coherent applications (ID16A at the ESRF) has been chosen to study in detail the issues related to highly demagnifying synchrotron sources and exploiting the beam coherence. The performance of the beamline is studied for two storage rings: the old ESRF-1 (emittance 4000~pm) and the new ESRF-EBS (emittance 150~pm). In addition to traditional results in terms of flux and beam sizes, an innovative study on the partial coherence properties based on the propagation of coherent modes is presented. The different algorithms and methodologies are implemented in the software suite OASYS. Those are discussed with emphasis placed upon the their benefits and limitations of each

    Serum cytokine and chemokine profiles and disease prognosis in hepatitis B virus-related acute-on-chronic liver failure

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    BackgroundHepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) has significant morbidity and mortality and is associated with the induction of cytokines/chemokines, which might contribute to the pathogenesis of liver injury. This study aimed to explore the cytokine/chemokine profiles of patients with HBV-ACLF and develop a composite clinical prognostic model.MethodsWe prospectively collected blood samples and the clinical data of 107 patients with HBV-ACLF admitted to the Beijing Ditan Hospital. The concentrations of 40-plex cytokines/chemokines were measured in 86 survivors and 21 non-survivors using the Luminex assay. Discrimination between the cytokine/chemokine profiles in different prognosis groups was analyzed using the multivariate statistical techniques of principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). An immune-clinical prognostic model was obtained using multivariate logistic regression analysis.ResultsThe PCA and PLS-DA indicated that cytokine/chemokine profiling could clearly distinguish patients with different prognoses. A total of 14 cytokines, namely, IL-1β, IL-6, IL-8, IL-10, TNF-α, IFN-γ, CXCL1, CXCL2, CXCL9, CXCL13, CX3CL1, GM-SCF, CCL21, and CCL23, were significantly correlated with disease prognosis. Multivariate analysis identified CXCL2, IL-8, total bilirubin, and age as independent risk factors that constituted the immune-clinical prognostic model, which showed the strongest predictive value of 0.938 compared with those of the Chronic Liver Failure Consortium (CLIF-C) ACLF (0.785), Model for End-Stage Liver Disease (MELD) (0.669), and MELD-Na (0.723) scores (p &lt; 0.05 for all).ConclusionThe serum cytokine/chemokine profiles correlated with the 90-day prognosis of patients with HBV-ACLF. The proposed composite immune-clinical prognostic model resulted in more accurate prognostic estimates than those of the CLIF-C ACLF, MELD, and MELD-Na scores

    Long-read sequencing-based transcriptomic landscape in longissimus dorsi and transcriptome-wide association studies for growth traits of meat rabbits

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    Rabbits are an attractive meat livestock species that can efficiently convert human-indigestible plant biomass, and have been commonly used in biological and medical researches. Yet, transcriptomic landscape in muscle tissue and association between gene expression level and growth traits have not been specially studied in meat rabbits. In this study Oxford Nanopore Technologies (ONT) long-read sequencing technology was used for comprehensively exploring transcriptomic landscape in Longissimus dorsi for 115 rabbits at 84 days of age, and transcriptome-wide association studies (TWAS) were performed for growth traits, including body weight at 84 days of age and average daily gain during three growth periods. The statistical analysis of TWAS was performed using a mixed linear model, in which polygenic effect was fitted as a random effect according to gene expression level-based relationships. A total of 18,842 genes and 42,010 transcripts were detected, among which 35% of genes and 47% of transcripts were novel in comparison with the reference genome annotation. Furthermore, 45% of genes were widely expressed among more than 90% of individuals. The proportions (±SE) of phenotype variance explained by genome-wide gene expression level ranged from 0.501 ± 0.216 to 0.956 ± 0.209, and the similar results were obtained when explained by transcript expression level. In contrast, neither gene nor transcript was detected by TWAS to be statistically significantly associated with these growth traits. In conclusion, these novel genes and transcripts that have been extensively profiled in a single muscle tissue using long-read sequencing technology will greatly improve our understanding on transcriptional diversity in rabbits. Our results with a relatively small sample size further revealed the important contribution of global gene expression to phenotypic variation on growth performance, but it seemed that no single gene has an outstanding effect; this knowledge is helpful to include intermediate omics data for implementing genetic evaluation of growth traits in meat rabbits

    Effect of the application of peanut shell, bamboo, and maize straw biochars on the bioavailability of Cd and growth of maize in Cd-contaminated soil

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    Biochar is a versatile, carbon-rich, organic material that can effectively immobilize Cd in the soil. In this study, peanut shell biochar (SP), maize straw biochar (MS), and bamboo straw biochar (BS) were applied in different proportions to evaluate their effects on the remediation of Cd-contaminated farmland soil and plant growth. The results revealed that both single and mixed applications of biochar substantially increased corn biomass and chlorophyll content compared to the unamended control treatment, while the malondialdehyde (MDA) and proline contents were largely unaffected. The bamboo straw block biochar with maize straw biochar at a mass ratio of 2:1 (DBM) significantly increased the dry total biomass of maize (+107.24% compared to the unamended soil). SP application has highly increased the SPAD value. PB with BS application at a mass ratio of 1:1 (MSB) significantly decreased the soluble sugar content (+21.81% compared to the unamended control soil). Soil pH was increased by the application of biochar alone and in combination with feedstocks. The soil content of Fe/Mn oxide-bound (OX) and exchangeable-bound Cd (EX) was decreased, whereas that of carbonate-bound Cd (CA), residue-bound Cd (RE), and organic-bound Cd (OM) contents increased. The Cd content in corn grains under MSB and SP application was markedly reduced by 42.62% and 31.48%, respectively, compared to the unamended control soil. Overall, MSB and SP applications were effective in improving soil quality and crop growth
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