472 research outputs found
Computational Design of Flexible Electride with Nontrivial Band Topology
Electrides, with their excess electrons distributed in crystal cavities playing the role of anions, exhibit a variety of unique electronic and magnetic properties. In this work, we employ the first-principles crystal structure prediction to identify a new prototype of A3B electride in which both interlayer spacings and intralayer vacancies provide channels to accommodate the excess electrons in the crystal. This A3B type of structure is calculated to be thermodynamically stable for two alkaline metals oxides (Rb3O and K3O). Remarkably, the unique feature of multiple types of cavities makes the spatial arrangement of anionic electrons highly flexible via elastic strain engineering and chemical substitution, in contrast to the previously reported electrides characterized by a single topology of interstitial electrons. More importantly, our first-principles calculations reveal that Rb3O is a topological Dirac nodal line semimetal, which is induced by the band inversion at the general electronic k momentums in the Brillouin zone associated with the intersitial electric charges. The discovery of flexible electride in combining with topological electronic properties opens an avenue for electride design and shows great promises in electronic device applications
Large spin Hall conductivity and excellent hydrogen evolution reaction activity in unconventional PtTe1.75 monolayer
Two-dimensional (2D) materials have gained lots of attention due to the
potential applications. In this work, we propose that based on first-principles
calculations, the (22) patterned PtTe monolayer with kagome lattice
formed by the well-ordered Te vacancy (PtTe) hosts large spin Hall
conductivity (SHC) and excellent hydrogen evolution reaction (HER) activity.
The unconventional nature relies on the band representation (BR) of the
highest valence band without SOC. The large SHC comes from the Rashba
spin-orbit coupling (SOC) in the noncentrosymmetric structure induced by the Te
vacancy. Even though it has a metallic SOC band structure, the
invariant is well defined due to the existence of the direct band gap and is
computed to be nontrivial. The calculated SHC is as large as 1.25 at the Fermi level (). By tuning the
chemical potential from to eV, it varies rapidly and
monotonically from to 3.1. In addition, we also find the Te vacancy in the patterned
monolayer can induce excellent HER activity. Our results not only offer a new
idea to search 2D materials with large SHC, i.e., by introducing
inversion-symmetry breaking vacancies in large SOC systems, but also provide a
feasible system with tunable SHC (by applying gate voltage) and excellent HER
activity
Triterpenoids and Sterols from the Leaves and Twigs of Melia azedarach
Two new triterpenoids (1 and 2) and a new sterol (3), together with six known constituents (4–9), were isolated from the leaves and twigs of Melia azedarach. Their chemical structures were elucidated on the basis of spectroscopic analysis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13659-014-0019-1) contains supplementary material, which is available to authorized users
Identify submitochondria and subchloroplast locations with pseudo amino acid composition: Approach from the strategy of discrete wavelet transform feature extraction
AbstractIt is very challenging and complicated to predict protein locations at the sub-subcellular level. The key to enhancing the prediction quality for protein sub-subcellular locations is to grasp the core features of a protein that can discriminate among proteins with different subcompartment locations. In this study, a different formulation of pseudoamino acid composition by the approach of discrete wavelet transform feature extraction was developed to predict submitochondria and subchloroplast locations. As a result of jackknife cross-validation, with our method, it can efficiently distinguish mitochondrial proteins from chloroplast proteins with total accuracy of 98.8% and obtained a promising total accuracy of 93.38% for predicting submitochondria locations. Especially the predictive accuracy for mitochondrial outer membrane and chloroplast thylakoid lumen were 82.93% and 82.22%, respectively, showing an improvement of 4.88% and 27.22% when other existing methods were compared. The results indicated that the proposed method might be employed as a useful assistant technique for identifying sub-subcellular locations. We have implemented our algorithm as an online service called SubIdent (http://bioinfo.ncu.edu.cn/services.aspx)
Anisotropic linear and nonlinear charge-spin conversion in topological semimetal SrIrO3
Over the past decade, utilizing spin currents in the linear response of
electric field to manipulate magnetization states via spin-orbit torques (SOTs)
is one of the core concepts for realizing a multitude of spintronic devices.
Besides the linear regime, recently, nonlinear charge-spin conversion under the
square of electric field has been recognized in a wide variety of materials
with nontrivial spin textures, opening an emerging field of nonlinear
spintronics. Here, we report the investigation of both linear and nonlinear
charge-spin conversion in one single topological semimetal SrIrO3(110) thin
film that hosts strong spin-orbit coupling and nontrivial spin textures in the
momentum space. In the nonlinear regime, the observation of crystalline
direction dependent response indicates the presence of anisotropic surface
states induced spin-momentum locking near the Fermi level. Such anisotropic
spin textures also give rise to spin currents in the linear response regime,
which mainly contributes to the fieldlike SOT component. Our work demonstrates
the power of combination of linear and nonlinear approaches in understanding
and utilizing charge-spin conversion in topological materials.Comment: 18 pages, 5 figure
Clearance of Free Silica in Rat Lungs by Spraying with Chinese Herbal Kombucha
The effects of spraying with kombucha and Chinese herbal kombucha were compared with treatments with tetrandrine in a rat silicosis model. Silica dust (50 mg) was injected into the lungs of rats, which were then treated with one of the experimental treatments for a month. The rats were then killed and the effects of the treatments were evaluated by examining the extent and severity of the histopathological lesions in the animals’ lungs, measuring their organ coefficients and lung collagen contents, determining the dry and wet weights of their lungs, and measuring the free silica content of the dried lungs. In addition, lavage was performed on whole lungs taken from selected rats, and the numbers and types of cells in the lavage fluid were counted. The most effective treatment in terms of the ability to reduce lung collagen content and minimize the formation of pulmonary histopathological lesions was tetrandrine treatment, followed by Chinese herbal kombucha and non-Chinese herbal kombucha. However, the lavage fluid cell counts indicated that tetrandrine treatment had severe adverse effects on macrophage viability. This effect was much less pronounced for the kombucha and Chinese herbal kombucha treatments. Moreover, the free silica levels in the lungs of animals treated with Chinese herbal kombucha were significantly lower than those for any other silica-exposed group. These preliminary results indicate that spraying with Chinese herbal kombucha preparations can effectively promote the discharge of silica dust from lung tissues. Chinese herbal kombucha inhalation may thus be a useful new treatment for silicosis and other pneumoconiosis diseases
A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III
We established a method on measuring the \dzdzb mixing parameter for
BESIII experiment at the BEPCII collider. In this method, the doubly
tagged events, with one decays to
CP-eigenstates and the other decays semileptonically, are used to
reconstruct the signals. Since this analysis requires good separation,
a likelihood approach, which combines the , time of flight and the
electromagnetic shower detectors information, is used for particle
identification. We estimate the sensitivity of the measurement of to be
0.007 based on a fully simulated MC sample.Comment: 6 pages, 7 figure
Clearance of Free Silica in Rat Lungs by Spraying with Chinese Herbal Kombucha
The effects of spraying with kombucha and Chinese herbal kombucha were compared with treatments with tetrandrine in a rat silicosis model. Silica dust (50 mg) was injected into the lungs of rats, which were then treated with one of the experimental treatments for a month. The rats were then killed, and the effects of the treatments were evaluated by examining the extent and severity of the histopathological lesions in the animals’ lungs, measuring their organ coefficients and lung collagen contents, determining the dry and wet weights of their lungs, and measuring the free silica content of the dried lungs. In addition, lavage was performed on whole lungs taken from selected rats, and the numbers and types of cells in the lavage fluid were counted. The most effective treatment in terms of the ability to reduce lung collagen content and minimize the formation of pulmonary histopathological lesions was tetrandrine treatment, followed by Chinese herbal kombucha and non‐Chinese herbal kombucha. However, the lavage fluid cell counts indicated that tetrandrine treatment had severe adverse effects on macrophage viability. This effect was much less pronounced for the kombucha and Chinese herbal kombucha treatments. Moreover, the free silica levels in the lungs of animals treated with Chinese herbal kombucha were significantly lower than those for any other silica‐exposed group. These preliminary results indicate that spraying with Chinese herbal kombucha preparations can effectively promote the discharge of silica dust from lung tissues. Chinese herbal kombucha inhalation may thus be a useful new treatment for silicosis and other pneumoconiosis diseases
Ultrahigh-sensitivity label-free singlemode- tapered no core-singlemode fiber immunosensor for Listeria monocytogenes detection
A challenge for optical fiber biosensor is to achieve ultrahigh sensitivity with narrow full width at half maximum (FWHM) of the spectrum. To address this challenge, an ultrahigh-sensitivity microfiber interferometer fiber ring laser (FRL) biosensor is proposed and investigated for Listeria monocytogenes (L. monocytogenes) detection. The fiber biosensor is composed of a singlemode- tapered no core-singlemode (STNS) fiber configuration, which is functionalized with the anti-L. monocytogenes antibodies. An Erbium Doped Fiber Amplifier is applied to the sensor to excite laser and thus reduce the FWHM of the spectrum, which significantly improved the limit of detection (LoD). The proposed STNS FRL biosensor has excellent reproducibility, specificity and sensitivity for L. monocytogenes. The developed STNS FRL biosensor can directly detect L. monocytogenes cells with LoD as low as 1.0 cell/mL, indicating the capability for detecting single cell of L. monocytogenes. Real lettuce and milk samples have been tested and test result in lettuce and milk samples has deviations within ±30% from that of Phosphate-buffered saline (PBS) for L. monocytogenes concentrations vary from 101 to 103 cells/mL(g). The developed STNS FRL biosensor has ultrahigh sensitivity, good stability, reproducibility, and specificity, which has potential applications in diseases/medical diagnostics
Proton-Boron Fusion Yield Increased by Orders of Magnitude with Foam Targets
A novel intense beam-driven scheme for high yield of the tri-alpha reaction
11B(p,{\alpha})2{\alpha} was investigated. We used a foam target made of
cellulose triacetate (TAC, C_9H_{16}O_8) doped with boron. It was then heated
volumetrically by soft X-ray radiation from a laser heated hohlraum and turned
into a homogenous, and long living plasma. We employed a picosecond laser pulse
to generate a high-intensity energetic proton beam via the well-known Target
Normal Sheath Acceleration (TNSA) mechanism. We observed up to 10^{10}/sr
{\alpha} particles per laser shot. This constitutes presently the highest yield
value normalized to the laser energy on target. The measured fusion yield per
proton exceeds the classical expectation of beam-target reactions by up to four
orders of magnitude under high proton intensities. This enhancement is
attributed to the strong electric fields and nonequilibrium thermonuclear
fusion reactions as a result of the new method. Our approach shows
opportunities to pursue ignition of aneutronic fusion
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