1,948 research outputs found
Geometric effects of a quarter of corrugated torus
In the spirit of the thin-layer quantization scheme, we give the effective
Shr\"{o}dinger equation for a particle confined to a corrugated torus, in which
the geometric potential is substantially changed by corrugation. We find the
attractive wells reconstructed by the corrugation not being at identical
depths, which is strikingly different from that of a corrugated nanotube,
especially in the inner side of the torus. By numerically calculating the
transmission probability, we find that the resonant tunneling peaks and the
transmission gaps are merged and broadened by the corrugation of the inner side
of torus. These results show that the quarter corrugated torus can be used not
only to connect two tubes with different radiuses in different directions, but
also to filter the particles with particular incident~energies.Comment: 7 pages, 8 figure
Constraints on ultra-slow-roll inflation with the NANOGrav 15-Year Dataset
Ultra-slow-roll~(USR) inflation predicts an exponential amplification of
scalar perturbations at small scales, which leads to a stochastic gravitational
wave background~(SGWB) through the coupling of the scalar and tensor modes at
the second-order expansion of the Einstein equation. In this work, we search
for such a scalar-induced SGWB from the NANOGrav 15-year (NG15) dataset, and
find that the SGWB from USR inflation could explain the observed data. We place
constraints on the amplitude of the scalar power spectrum to at confidence level (C.L.) at the scale of . We find that degenerates with
the peak scale . We also obtain the parameter space
allowed by the data in the USR inflationary scenario, where the -folding
numbers of the duration of the USR phase has a lower limit
( C.L.) when the USR phase ends at . Since the priors for
the model parameters %in the USR model are uncertain, we do not calculate the
Bayes factors. Instead, to quantify the goodness of fit, we calculate the
maximum values of the log-likelihood for USR inflation, bubble collision of the
cosmological phase transition, and inspiraling supermassive black hole binaries
(SMBHBs), respectively. Our results imply that the SGWB from USR inflation can
fit the data better than the one from SMBHBs.Comment: 6 pages, 4 figure
Bis(μ-2-hydroxybenozato)-κ3 O,O′:O′;κ3 O:O,O′-bis[(2-hydroxybenozato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)cadmium(II)]
The dinuclear title compound, [Cd2(C7H5O3)4(C12H8N2)2], is located on a crystallographic rotation twofold axis. The two CdII ions are connected by two tridentate bridging 2-hydroxybenzoate anions. Each CdII ion is seven-coordinated by five O atoms from three 2-hydroxybenzoate ligands and two N atoms from 1,10-phenanthroline. The 2-hydroxybenzoate molecules adopt two kinds of coordination mode, bidentate chelating and tridentate bridging–chelating. Intramolecular hydrogen bonds between hydroxy and carboxylate groups from 2-hydroxybenzoate groups and π–π stacking interactions between parallel 1,10-phenanthroline ligands [centroid–centroid distances = 3.707 (3) and 3.842 (3) Å] are observed. Furthermore, adjacent benzene rings from 2-hydroxybenzoate ligands are involved in π–π interactions with interplanar distances of 3.642 (3) Å, thereby forming a chain along the a axis direction
Metasomatized lithospheric mantle for Mesozoic giant gold deposits in the North China craton
The origin of giant lode gold deposits of Mesozoic age in the North China craton (NCC) is enigmatic because high-grade metamorphic ancient crust would be highly depleted in gold. Instead, lithospheric mantle beneath the crust is the likely source of the gold, which may have been anomalously enriched by metasomatic processes. However, the role of gold enrichment and metasomatism in the lithospheric mantle remains unclear. Here, we present comprehensive data on gold and platinum group element contents of mantle xenoliths (n = 28) and basalts (n = 47) representing the temporal evolution of the eastern NCC. The results indicate that extensive mantle metasomatism and hydration introduced some gold (<1–2 ppb) but did not lead to a gold-enriched mantle. However, volatile-rich basalts formed mainly from the metasomatized lithospheric mantle display noticeably elevated gold contents as compared to those from the asthenosphere. Combined with the significant inheritance of mantle-derived volatiles in auriferous fluids of ore bodies, the new data reveal that the mechanism for the formation of the lode gold deposits was related to the volatile-rich components that accumulated during metasomatism and facilitated the release of gold during extensional craton destruction and mantle melting. Gold-bearing, hydrous magmas ascended rapidly along translithospheric fault zones and evolved auriferous fluids to form the giant deposits in the crust
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Optical biopsy identification and grading of gliomas using label-free visible resonance Raman spectroscopy.
Glioma is one of the most refractory types of brain tumor. Accurate tumor boundary identification and complete resection of the tumor are essential for glioma removal during brain surgery. We present a method based on visible resonance Raman (VRR) spectroscopy to identify glioma margins and grades. A set of diagnostic spectral biomarkers features are presented based on tissue composition changes revealed by VRR. The Raman spectra include molecular vibrational fingerprints of carotenoids, tryptophan, amide I/II/III, proteins, and lipids. These basic in situ spectral biomarkers are used to identify the tissue from the interface between brain cancer and normal tissue and to evaluate glioma grades. The VRR spectra are also analyzed using principal component analysis for dimension reduction and feature detection and support vector machine for classification. The cross-validated sensitivity, specificity, and accuracy are found to be 100%, 96.3%, and 99.6% to distinguish glioma tissues from normal brain tissues, respectively. The area under the receiver operating characteristic curve for the classification is about 1.0. The accuracies to distinguish normal, low grade (grades I and II), and high grade (grades III and IV) gliomas are found to be 96.3%, 53.7%, and 84.1% for the three groups, respectively, along with a total accuracy of 75.1%. A set of criteria for differentiating normal human brain tissues from normal control tissues is proposed and used to identify brain cancer margins, yielding a diagnostic sensitivity of 100% and specificity of 71%. Our study demonstrates the potential of VRR as a label-free optical molecular histopathology method used for in situ boundary line judgment for brain surgery in the margins
Evolution of an intron-poor cluster of the CIPK gene family and expression in response to drought stress in soybean
Calcium ion is an intracellular messenger that plays a central role in signal transduction pathways. Calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs) signal network have shown different functions in the Ca2+ signaling process. In this work, we identified the entire soybean (Glycine max) CIPK gene family, which comprised 52 genes and divided into four subgroups (I to IV) based on phylogeny. The gene structural analysis separated these 52 genes into an intron-rich clade and an intron-poor clade. Chromosomal location analysis resulted in the identification of 22 duplicated blocks and six tandem duplication events. Phylogenetic classification of 193 CIPK proteins from representative plant species suggested that the intron-poor clade of CIPKs originated in seed plants. Analysis of global gene expression patterns of soybean CIPK family revealed that most intron-poor soybean CIPK genes are drought-inducible; a finding that was further confirmed using qRT-PCR. Our study provides a foundation for further functional analysis to reveal the roles that CIPKs and more specifically the intron-poor clade play in drought tolerance in soybean
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