74 research outputs found
Quantization and diagnosis of Shanghuo (Heatiness) in Chinese medicine using a diagnostic scoring scheme and salivary biochemical parameters
Background: This study aims to establish a diagnostic scoring scheme for Shanghuo (Heatiness) and to evaluate whether Shanghuo is associated with biochemical parameters of salivary lysozyme (LYZ), salivary secreted immunoglobulin (S-IgA), salivary amylase (AMS), and saliva flow rate (SFR). Methods: We collected 121 Shanghuo patients at the Affiliated Hospitals of Guangzhou University of Traditional Chinese Medicine in Guangdong Province, 60 cases as a Shanghuo recovered group, and 60 healthy cases as a healthy control group. The diagnostic scoring scheme was established by probability theory and maximum likelihood discriminatory analysis on the basis of epidemiology with the design of self-controlled clinical trial. Subsequently, we used the same methods to collect 120 Shanghuo patients, 60 Shanghuo recovered cases, and 60 healthy cases in both Hunan Province and Henan Province. The levels of LYZ, S-IgA, AMS, and SFR were tested when the patients suffered from Shanghuo or recovered, respectively. Results: The diagnostic score table for Shanghuo syndrome was established first. In the retrospective tests, the sensitivity, specificity, accuracy, and positive likelihood ratio of the diagnostic score table were 98.9%, 93.5%, 97.5%, and 14.34%, respectively. In the prospective tests, the corresponding values were 94.9%, 85.7%, 91.7%, and 6.64%, respectively. Shanghuo was classified into three degrees based on the diagnostic scores, common Shanghuo: 63–120; serious Shanghuo: 121–150; very serious Shanghuo: >150. A negative correlation was found between Shanghuo and S-IgA (R = -0.428; P = 0.000). The level of S-IgA was also affected by seasonal and regional factors. No significant correlations were found between Shanghuo and the levels of LYZ, AMS, and SFR. Conclusions: In this study, Shanghuo could be diagnosed by the combination of the diagnostic score table and S-lgA level
A Bandpass Filter Based on Half Mode Substrate Integrated Waveguide-to-Defected Ground Structure Cells
A half mode substrate integrated waveguide-to-defected ground structure (HMSIW-DGS) cell and its embedded form are proposed to miniaturize a bandpass filter. Both cells can purchase wideband frequency response and low insertion loss, as well as simple and easy fabrication. By cascading two of them according to design requirement, an X-band bandpass filter is designed and measured to meet compact size, low insertion loss, good return loss, second harmonic suppression, and linear phase
Scaling of Berry-curvature monopole dominated large linear positive magnetoresistance
The linear positive magnetoresistance (LPMR) is a widely observed phenomenon
in topological materials, which is promising for potential applications on
topological spintronics. However, its mechanism remains ambiguous yet and the
effect is thus uncontrollable. Here, we report a quantitative scaling model
that correlates the LPMR with the Berry curvature, based on a ferromagnetic
Weyl semimetal CoS2 that bears the largest LPMR of over 500% at 2 Kelvin and 9
Tesla, among known magnetic topological semimetals. In this system, masses of
Weyl nodes existing near the Fermi level, revealed by theoretical calculations,
serve as Berry-curvature monopoles and low-effective-mass carriers. Based on
the Weyl picture, we propose a relation , with B being the applied magnetic field and the average Berry curvature near the Fermi surface, and further
introduce temperature factor to both MR/B slope (MR per unit field) and
anomalous Hall conductivity, which establishes the connection between the model
and experimental measurements. A clear picture of the linearly slowing down of
carriers, i.e., the LPMR effect, is demonstrated under the cooperation of the
k-space Berry curvature and real-space magnetic field. Our study not only
provides an experimental evidence of Berry curvature induced LPMR for the first
time, but also promotes the common understanding and functional designing of
the large Berry-curvature MR in topological Dirac/Weyl systems for magnetic
sensing or information storage
Probing the fractional quantum Hall phases in valley-layer locked bilayer MoS
Semiconducting transition-metal dichalcogenides (TMDs) exhibit high mobility,
strong spin-orbit coupling, and large effective masses, which simultaneously
leads to a rich wealth of Landau quantizations and inherently strong electronic
interactions. However, in spite of their extensively explored Landau levels
(LL) structure, probing electron correlations in the fractionally filled LL
regime has not been possible due to the difficulty of reaching the quantum
limit. Here, we report evidence for fractional quantum Hall (FQH) states at
filling fractions 4/5 and 2/5 in the lowest LL of bilayer MoS, manifested
in fractionally quantized transverse conductance plateaus accompanied by
longitudinal resistance minima. We further show that the observed FQH states
sensitively depend on the dielectric and gate screening of the Coulomb
interactions. Our findings establish a new FQH experimental platform which are
a scarce resource: an intrinsic semiconducting high mobility electron gas,
whose electronic interactions in the FQH regime are in principle tunable by
Coulomb-screening engineering, and as such, could be the missing link between
atomically thin graphene and semiconducting quantum wells.Comment: 10 pages, 4 figure
Growth and characterization of A_{1-x}K_xFe_2As_2 (A = Ba, Sr) single crystals with x=0 - 0.4
Single crystals of AKFeAs (A=Ba, Sr) with high quality
have been grown successfully by FeAs self-flux method. The samples have sizes
up to 4 mm with flat and shiny surfaces. The X-ray diffraction patterns suggest
that they have high crystalline quality and c-axis orientation. The
non-superconducting crystals show a spin-density-wave (SDW) instability at
about 173 K and 135 K for Sr-based and Ba-based compound, respectively. After
doping K as the hole dopant into the BaFeAs system, the SDW transition
is smeared, and superconducting samples with the compound of
BaKFeAs (0 0.4) are obtained. The
superconductors characterized by AC susceptibility and resistivity measurements
exhibit very sharp superconducting transition at about 36 K, 32 K, 27 K and 23
K for x= 0.40,0.28,0.25 and 0.23, respectively.Comment: 9 pages, 6 figures, 1 table. This paper together with new data are
modified into a new pape
Effects of Anomalous Arctic Polar Vortex on Vegetation Growth in Northern Eurasia
The northern Eurasia is a region heavily affected by the Arctic polar vortex (APV). Understanding the vegetation responses to anomalous APV in this region is important for dealing with climate change. In this study, we investigated the impacts and mechanism of the anomalous APV phases on the vegetation dynamics in the northern Eurasia. The larger and smaller APV phases correspond to almost opposite atmospheric circulation patterns which result in opposite vegetation responses. The decreased (increased) solar radiation, the enhanced (weakened) northerly winds, together with the decreased (increased) water vapor divergence, caused the decreasing (increasing) of the air temperature, increasing (decreasing) of the precipitation and soil moisture in the study area during the larger (smaller) APV phase. The response of vegetation growth to the APV depends on climate change and vegetation sensitivity to it. In most parts of the study area, vegetation growth was positively associated with air temperature, and hence, vegetation was suppressed (promoted) during the larger (smaller) APV phase. In the northeast of the Caspian Sea (NCS), vegetation growth was sensitive to precipitation. Therefore, the increased (decreased) soil moisture in summer and autumn were responsible for the promoted (suppressed) vegetation growth during the larger (smaller) APV phase. (Citation: Gong, H., M. Huang, and Z. Wang, 2021: Effects of anomalous Arctic polar vortex on vegetation growth in northern Eurasia. SOLA, 17, 151-157, doi:10.2151/sola.2021-027.
Experimental Study on Energy Dissipation Performance and Failure Mode of Web-Connected Replaceable Energy Dissipation Link
In the current design method of the eccentrically braced frame structure, the energy dissipation link and the frame beam are both designed as a whole. It is difficult to accurately assess the degree of damage through this method, and it is also hard to repair or replace the energy dissipation link after strong seismic events. Meanwhile, the overall design approach will increase the project’s overall cost. In order to solve the above mentioned shortcomings, the energy dissipation link is designed as an independent component, which is separated from the frame beam. In this paper, the energy dissipation link is bolted to the web of the frame beam. Both finite element simulation and test study of eight groups of energy dissipation links have been completed to study their mechanical behaviors, and the energy dissipation links have been studied in the aspects of length, cross section, and stiffener spacing. The mechanical behaviors include the energy dissipation behavior, bearing capacity, stiffness, and plastic rotation angle. The results indicate clearly that the hysteretic loop of links in the test and finite element analysis is relatively full. By comparing the experimental and finite element simulation data, it can be found that the general shape and trend of hysteretic loop, skeleton curve, and stiffness degradation curve are basically the same. The experiment data explicitly shows that the energy dissipation link of web-connected displays good ductility and stable energy dissipation ability. In addition, the replaceable links possess good rotational capacity when the minimum rotation angle of each specimen in the test is 0.16 rad. The results of the experiment show that the energy dissipation capacity of the link is mainly related to the section size and the stiffening rib spacing of the link. The energy dissipation ability and deformation ability of the link is poorer as the section size becomes larger; meanwhile, these abilities are reduced with the decrease of the stiffening spacing. The experiment result shows that the damage and excessive inelastic deformations are concentrated in the link to avoid any issues for the rest of the surrounding elements, and the links can be easily and inexpensively replaced after strong seismic events. The results are thought provoking, as they provide a theoretical basis for the further study of the eccentrically braced frame structure with replaceable links of web-connected. In future work, the author aims to carry out his studies through optimized design methodology based on the yielding criterion
Metal-Free Photoredox Intramolecular Cyclization of N-Aryl Acrylamides
A novel metal-free photoredox-catalyzed cyclization reaction of N-aryl acrylamide is herein reported that provides synthetically valuable oxindole derivatives through the bis-mediation of H2O and aldehyde. In this work, sustainable visible light was used as the energy source, and the organic light-emitting molecule 4CzIPN served as the efficient photocatalyst. The main characteristics of this reaction are environmentally friendly and high yields
Comparison of the Partition Efficiencies of Multiple Phenolic Compounds Contained in Propolis in Different Modes of Acetonitrile–Water-Based Homogenous Liquid–Liquid Extraction
Homogeneous liquid⁻liquid extraction (HLLE) has attracted considerable interest in the sample preparation of multi-analyte analysis. In this study, HLLEs of multiple phenolic compounds in propolis, a polyphenol-enriched resinous substance collected by honeybees, were performed for improving the understanding of the differences in partition efficiencies in four acetonitrile⁻water-based HLLE methods, including salting-out assisted liquid⁻liquid extraction (SALLE), sugaring-out assisted liquid⁻liquid extraction (SULLE), hydrophobic-solvent assisted liquid⁻liquid extraction (HSLLE), and subzero-temperature assisted liquid⁻liquid extraction (STLLE). Phenolic compounds were separated in reversed-phase HPLC, and the partition efficiencies in different experimental conditions were evaluated. Results showed that less-polar phenolic compounds (kaempferol and caffeic acid phenethyl ester) were highly efficiently partitioned into the upper acetonitrile (ACN) phase in all four HLLE methods. For more-polar phenolic compounds (caffeic acid, p-coumaric acid, isoferulic acid, dimethoxycinnamic acid, and cinnamic acid), increasing the concentration of ACN in the ACN⁻H2O mixture could dramatically improve the partition efficiency. Moreover, results indicated that NaCl-based SALLE, HSLLE, and STLLE with ACN concentrations of 50:50 (ACN:H2O, v/v) could be used for the selective extraction of low-polarity phenolic compounds. MgSO4-based SALLE in the 50:50 ACN⁻H2O mixture (ACN:H2O, v/v) and the NaCl-based SALLE, SULLE, and STLLE with ACN concentrations of 70:30 (ACN:H2O, v/v) could be used as general extraction methods for multiple phenolic compounds
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