781 research outputs found
Multiple magnetoplasmon polaritons of magneto-optical graphene in near-field radiative heat transfer
Graphene, as a two-dimensional magneto-optical material, supports
magnetoplasmon polaritons (MPP) when exposed to an applied magnetic field.
Recently, MPP of a single-layer graphene has shown an excellent capability in
the modulation of near-field radiative heat transfer (NFRHT). In this study, we
present a comprehensive theoretical analysis of NFRHT between two multilayered
graphene structures, with a particular focus on the multiple MPP effect. We
reveal the physical mechanism and evolution law of the multiple MPP, and we
demonstrate that the multiple MPP allow one to mediate, enhance, and tune the
NFRHT by appropriately engineering the properties of graphene, the number of
graphene sheets, the intensity of magnetic fields, as well as the geometric
structure of systems. We show that the multiple MPP have a quite significant
distinction relative to the single MPP or multiple surface plasmon polaritons
(SPPs) in terms of modulating and manipulating NFRHT
Constraints on the cosmological parameters with three-parameter correlation of Gamma-ray bursts
As one of the most energetic and brightest events, gamma-ray bursts (GRBs)
can be treated as a promising probe of the high-redshift universe. Similar to
type Ia supernovae (SNe Ia), GRBs with same physical origin could be treated as
standard candles. We select GRB samples with the same physical origin, which
are divided into two groups. One group is consisted of 31 GRBs with a plateau
phase feature of a constant luminosity followed by a decay index of about -2 in
the X-ray afterglow light curves, and the other has 50 GRBs with a shallow
decay phase in the optical light curves. For the selected GRB samples, we
confirm that there is a tight correlation between the plateau luminosity ,
the end time of plateau and the isotropic energy release
. We also find that the correlation is
insensitive to the cosmological parameters and no valid limitations on the
cosmological parameters can be obtained using this correlation. We explore a
new three-parameter correlation , , and the spectral peak energy in
the rest frame (), and find that this correlation
can be used as a standard candle to constrain the cosmological parameters. By
employing the optical sample only, we find the constraints of for a flat CDM model. For the
non-flat CDM model, the best-fitting results are , . For the combination of the X-ray and optical
smaples, we find for a flat
CDM model, and , for a non-flat CDM model.Comment: Accepted for publication in The Astrophysical Journal, 13 pages, 9
figures and 2 table
Development of a Generic PCR Detection of 3-Acetyldeoxy-nivalenol-, 15-Acetyldeoxynivalenol- and Nivalenol-Chemotypes of Fusarium graminearum Clade
Fusarium graminearum clade pathogens cause Fusarium head blight (FHB) or scab of wheat and other small cereal grains, producing different kinds of trichothecene mycotoxins that are detrimental to human and domestic animals. Type B trichothecene mycotoxins such as deoxynivalenol, 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON) and nivalenol (NIV) are the principal Fusarium mycotoxins reported in China, as well as in other countries. A genomic polymerase chain reaction (PCR) to predict chemotypes was developed based on the structural gene sequences of Tri13 genes involved in trichothecene mycotoxin biosynthesis pathways. A single pair of primers derived from the Tri13 genes detected a 583 bp fragment from 15-AcDON-chemotypes, a 644 bp fragment from 3-AcDON-chemotypes and an 859 bp fragment from NIV-producing strains. Fusarium strains from China, Nepal, USA and Europe were identified by this method, revealing their mycotoxin chemotypes identical to that obtained by chemical analyses of HPLC or GC/MS and other PCR assays. The mycotoxin chemotype-specific fragments were amplified from a highly variable region located in Tri13 genes with three deletions for 15-AcDON-chemotypes, two deletions for 3-AcDON-chemotypes and no deletion for NIV-producers. This PCR assay generated a single amplicon and thus should be more reliable than other PCR-based assays that showed the absence or presence of a PCR fragment since these assays may generate false-negative results. The results with strains from several different countries as well as from different hosts further indicated that this method should be globally applicable. This is a rapid, reliable and cost-effective method for the identification of type B trichothecene mycotoxin chemotypes in Fusarium species and food safety controls
Radio Plateaus in Gamma-Ray Burst Afterglows and Their Application in Cosmology
The plateau phase in the radio afterglows has been observed in very few
gamma-ray bursts (GRBs), and 27 radio light curves with plateau phase were
acquired from the published literature in this article. We obtain the related
parameters of the radio plateau, such as temporal indexes during the plateau
phase ( and ), break time (\Tbz) and the corresponding
radio flux (). The two parameter Dainotti relation between the break
time of the plateau and the corresponding break luminosity (\Lbz) in radio
band is \Lbz \propto \Tbz^{-1.20\pm0.24}. Including the isotropic energy
\Eiso and the peak energy \Epi, the three parameter correlations for the
radio plateaus are written as \Lbz \propto \Tbz^{-1.01 \pm 0.24} \Eiso^{0.18
\pm 0.09} and \Lbz \propto \Tbz^{-1.18 \pm 0.27} \Epi^{0.05 \pm 0.28},
respectively. The correlations are less consistent with that of X-ray and
optical plateaus, implying that radio plateaus may have a different physical
mechanism. The typical frequencies crossing the observational band may be a
reasonable hypothesis that causes the breaks of the radio afterglows. We
calibrate GRBs empirical luminosity correlations as standard candle for
constraining cosmological parameters, and find that our samples can constrain
the flat CDM model well, while are not sensitive to non-flat
CDM model. By combining GRBs with other probes, such as SN and CMB,
the constraints on cosmological parameters are \om = 0.297\pm0.006 for the
flat CDM model and \om = 0.283\pm0.008, \oL = 0.711\pm0.006 for
the non-flat CDM model, respectively.Comment: 16 pages, 6 figures and 6 tables, accepted for publication in Ap
Yin-Cold
Traditional Chinese Medicine (TCM) therapies should be tailored according to the different syndrome types. In order to identify the relationship between the TCM Yin-cold (YC) or Yang-heat (YH) syndrome types and the EGFR gene status, we prospectively studied 310 NSCLC patients. TCM YH or YC was diagnosed by three TCM experts. TCM symptoms and signs were entered into a binary cluster analysis. The relationships between the EGFR gene status, YH or YC syndrome types, and classification by cluster analysis were analyzed using the chi-square test and multivariate logistic regression. In the 299 patients who had their EGFR gene tested, 45.24% YC (76/168) and 25.95% YH (34/131) patients had EGFR mutations (p=0.001). Among the 292 patients entered into the cluster analysis, 132 were classified into group A, with signs and symptoms similar to YC, whereas 160 group B patients were similar to YH. In the 281 patients with EGFR tested, 45.67% group A (58/127) and 28.57% group B patients (44/154) had EGFR mutations (p=0.003). The EGFR status was independently correlated with TCM syndrome type and classification by cluster analysis on multivariate logistic regression. NSCLC patients with YC were more likely to have EGFR gene mutations
Improved Spatial Resolution Achieved by Chromatic Intensity Interferometry
Interferometers are widely used in imaging technologies to achieve enhanced
spatial resolution, but require that the incoming photons be indistinguishable.
In previous work, we built and analyzed color erasure detectors which expand
the scope of intensity interferometry to accommodate sources of different
colors. Here we experimentally demonstrate how color erasure detectors can
achieve improved spatial resolution in an imaging task, well beyond the
diffraction limit. Utilizing two 10.9 mm-aperture telescopes and a 0.8 m
baseline, we measure the distance between a 1063.6 nm source and a 1064.4 nm
source separated by 4.2 mm at a distance of 1.43 km, which surpasses the
diffraction limit of a single telescope by about 40 times. Moreover, chromatic
intensity interferometry allows us to recover the phase of the Fourier
transform of the imaged objects - a quantity that is, in the presence of modest
noise, inaccessible to conventional intensity interferometry.Comment: 5 pages, 3 figure
Insights into the Ecological Roles and Evolution of Methyl-Coenzyme M Reductase-Containing Hot Spring Archaea
Several recent studies have shown the presence of genes for the key enzyme associated with archaeal methane/alkane metabolism, methyl-coenzyme M reductase (Mcr), in metagenome-assembled genomes (MAGs) divergent to existing archaeal lineages. Here, we study the mcr-containing archaeal MAGs from several hot springs, which reveal further expansion in the diversity of archaeal organisms performing methane/alkane metabolism. Significantly, an MAG basal to organisms from the phylum Thaumarchaeota that contains mcr genes, but not those for ammonia oxidation or aerobic metabolism, is identified. Together, our phylogenetic analyses and ancestral state reconstructions suggest a mostly vertical evolution of mcrABG genes among methanogens and methanotrophs, along with frequent horizontal gene transfer of mcr genes between alkanotrophs. Analysis of all mcr-containing archaeal MAGs/genomes suggests a hydrothermal origin for these microorganisms based on optimal growth temperature predictions. These results also suggest methane/alkane oxidation or methanogenesis at high temperature likely existed in a common archaeal ancestor
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