Interfacial stiffness dependence of the effective magnetostriction of particulate magnetostrictive composites

AbstractTerfenol-D composites attract much attention recently due to their large magnetostriction, small eddy energy loss and large operation frequency bandwidth. Binder layer in the composite usually mechanically weakens the composite and reduces the effective properties. A typical kind of magnetostictive composite is composed of Rare Earth metallic compound powder, matrix material and resin binder. The binder, which is usually flexible and forms mechanically weak interface in the composite, inevitably influences the overall magnetostriction of composites. In this paper, a theoretical model was developed to treat a simple deformation case of this kind of mechanically weak interface, in which the flexible layer has low stiffness to withstand deformation but no de-bonding or cracking. An infinite magnetostrictive plane with a circular inclusion was considered, where the matrix and inclusion are all general magnetostrictive materials which can be modeled by the standard square constitutive relation of magnetostriction. The binder layer of a certain thickness was modeled as a set of springs with no thickness but with an equivalent stiffness. The mathematical formulation was brought into the complex variable framework. The magnetoelastic field was solved and the effective magnetostriction was explicitly obtained. Comparisons with experimental results were also presented. In terms of this analysis, the interfacial stiffness has significant influences on the overall magnetostriction of composite. Increasing the interfacial stiffness can lead to large magnetostriction of composites. The measure for improving the interfacial stiffness includes increasing the binder modulus and reducing its thickness

Quantum Transport and Band Structure Evolution under High Magnetic Field in Few-Layer Tellurene

Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states which only occurs in confined two-dimensional electron gas (2DEG) systems. Experimentally, QHE is hosted in high mobility 2DEG with large external magnetic field at low temperature. Two-dimensional van der Waals materials, such as graphene and black phosphorus, are considered interesting material systems to study quantum transport, because it could unveil unique host material properties due to its easy accessibility of monolayer or few-layer thin films at 2D quantum limit. Here for the first time, we report direct observation of QHE in a novel low-dimensional material system: tellurene.High-quality 2D tellurene thin films were acquired from recently reported hydrothermal method with high hole mobility of nearly 3,000 cm2/Vs at low temperatures, which allows the observation of well-developed Shubnikov-de-Haas (SdH) oscillations and QHE. A four-fold degeneracy of Landau levels in SdH oscillations and QHE was revealed. Quantum oscillations were investigated under different gate biases, tilted magnetic fields and various temperatures, and the results manifest the inherent information of the electronic structure of Te. Anomalies in both temperature-dependent oscillation amplitudes and transport characteristics were observed which are ascribed to the interplay between Zeeman effect and spin-orbit coupling as depicted by the density functional theory (DFT) calculations

Effect of a structurally modified human granulocyte colony stimulating factor, G-CSFa, on leukopenia in mice and monkeys

<p>Abstract</p> <p>Background</p> <p>Granulocyte colony stimulating factor (G-CSF) regulates survival, proliferation, and differentiation of neutrophilic granulocyte precursors, Recombinant G-CSF has been used for the treatment of congenital and therapy-induced neutropenia and stem cell mobilization. Due to its intrinsic instability, recombinant G-CSF needs to be excessively and/or frequently administered to patients in order to maintain a plasma concentration high enough to achieve therapeutic effects. Therefore, there is a need for the development of G-CSF derivatives that are more stable and active in vivo.</p> <p>Methods</p> <p>Using site-direct mutagenesis and recombinant DNA technology, a structurally modified derivative of human G-CSF termed G-CSFa was obtained. G-CSFa contains alanine 17 (instead of cysteine 17 as in wild-type G-CSF) as well as four additional amino acids including methionine, arginine, glycine, and serine at the amino-terminus. Purified recombinant G-CSFa was tested for its in vitro activity using cell-based assays and in vivo activity using both murine and primate animal models.</p> <p>Results</p> <p>In vitro studies demonstrated that G-CSFa, expressed in and purified from <it>E. coli</it>, induced a much higher proliferation rate than that of wild-type G-CSF at the same concentrations. In vivo studies showed that G-CSFa significantly increased the number of peripheral blood leukocytes in cesium-137 irradiated mice or monkeys with neutropenia after administration of clyclophosphamide. In addition, G-CSFa increased neutrophil counts to a higher level in monkeys with a concomitant slower declining rate than that of G-CSF, indicating a longer half-life of G-CSFa. Bone marrow smear analysis also confirmed that G-CSFa was more potent than G-CSF in the induction of granulopoiesis in bone marrows of myelo-suppressed monkeys.</p> <p>Conclusion</p> <p>G-CSFa, a structurally modified form of G-CSF, is more potent in stimulating proliferation and differentiation of myeloid cells of the granulocytic lineage than the wild-type counterpart both in vitro and in vivo. G-CSFa can be explored for the development of a new generation of recombinant therapeutic drug for leukopenia.</p

Natural Coevolution of Tumor and Immunoenvironment in Glioblastoma.

Isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) has a dismal prognosis. A better understanding of tumor evolution holds the key to developing more effective treatment. Here we study GBM\u27s natural evolutionary trajectory by using rare multifocal samples. We sequenced 61,062 single cells from eight multifocal IDH wild-type primary GBMs and defined a natural evolution signature (NES) of the tumor. We show that the NES significantly associates with the activation of transcription factors that regulate brain development, including MYBL2 and FOSL2. Hypoxia is involved in inducing NES transition potentially via activation of the HIF1A-FOSL2 axis. High-NES tumor cells could recruit and polarize bone marrow-derived macrophages through activation of the FOSL2-ANXA1-FPR1/3 axis. These polarized macrophages can efficiently suppress T-cell activity and accelerate NES transition in tumor cells. Moreover, the polarized macrophages could upregulate CCL2 to induce tumor cell migration. SIGNIFICANCE: GBM progression could be induced by hypoxia via the HIF1A-FOSL2 axis. Tumor-derived ANXA1 is associated with recruitment and polarization of bone marrow-derived macrophages to suppress the immunoenvironment. The polarized macrophages promote tumor cell NES transition and migration. This article is highlighted in the In This Issue feature, p. 2711

Hydrological processes in the different landscape zones of alpine cold regions in the wet season, combining isotopic and hydrochemical tracers

C1 - Journal Articles Referee

A Novel Inverse Synthetic Aperture Radar Imaging Method for Maneuvering Targets Based on Modified Chirp Fourier Transform

When inverse synthetic aperture radar (ISAR) imaging maneuvers targets, the azimuth echo of the target scattering point causes a Doppler frequency time-varying problem, which leads to the blurring and defocusing of the imaging results. Traditional imaging methods struggle to meet the imaging requirements for maneuvering targets due to a poor imaging effect or low efficiency. Given these challenges, a modified chirp Fourier transform (MCFT) imaging method is proposed in this paper, based on the specific relationship between the target rotation parameters and the radar echo signal parameters. Firstly, discrete chirp Fourier transform is used to quickly estimate the target&#8217;s coarse rotation ratio. Then, the minimum entropy function and gradient descent method are used to calculate the target&#8217;s accurate rotation ratio. Finally, the azimuth focusing image is accomplished by performing MCFT once on the azimuth echo signal using the accurate rotation ratio. This method avoids estimating and separating the sub-echo components one-by-one, considerably improves the imaging speed, and guarantees the best imaging quality by applying the global minimum entropy principle. The experimental results show that the proposed method effectively achieves the two-dimensional, high-quality, and fast imaging of maneuvering targets

Influence of Surface Preprocessing on 4H-SiC Wafer Slicing by Using Ultrafast Laser

The physical properties of silicon carbide (SiC) are excellent as a third-generation semiconductor. Nevertheless, diamond wire cutting has many drawbacks, including high loss, long cutting time and prolonged processing time. The study of 4H-SiC wafer slicing by using an ultrafast laser is hopeful for solving these problems. In this work, the 4H-SiC samples with different surface roughness were processed by laser slicing. Findings revealed that good surface quality could reduce the damage to the wafer surface during laser slicing, reduce cleavage, and improve the flatness and uniformity of the modified layer. Thus, preprocessing on 4H-SiC can significantly improve the quality and efficiency of laser slicing

Quantum Transport and Band Structure Evolution under High Magnetic Field in Few-Layer Tellurene.

Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states that only occurs in confined two-dimensional electron gas (2DEG) systems. Experimentally, QHE is hosted in high-mobility 2DEG with large external magnetic field at low temperature. Two-dimensional van der Waals materials, such as graphene and black phosphorus, are considered interesting material systems to study quantum transport because they could unveil unique host material properties due to the easy accessibility of monolayer or few-layer thin films at the 2D quantum limit. For the first time, we report direct observation of QHE in a novel low-dimensional material system, tellurene. High-quality 2D tellurene thin films were acquired from recently reported hydrothermal method with high hole mobility of nearly 3000 cm2/(V s) at low temperatures, which allows the observation of well-developed Shubnikov-de Haas (SdH) oscillations and QHE. A four-fold degeneracy of Landau levels in SdH oscillations and QHE was revealed. Quantum oscillations were investigated under different gate biases, tilted magnetic fields, and various temperatures, and the results manifest the inherent information on the electronic structure of Te. Anomalies in both temperature-dependent oscillation amplitudes and transport characteristics were observed that are ascribed to the interplay between the Zeeman effect and spin-orbit coupling, as depicted by the density functional theory calculations

Computed tomographic manifestations of celiac ganglia between hypertensive and non‐hypertensive population

Abstract The celiac ganglion (CG) is associated with the sympathetic nervous system (SNS) and plays an important role in the pathogenesis of hypertension. The characteristics of the CG in patients with hypertension remain unknown. The aim of our study was to explore the differences in celiac ganglia (CGs) characteristics between hypertensive and non‐hypertensive populations using computed tomography (CT). CGs manifestations on multidetector row CT in 1003 patients with and without hypertension were retrospectively analyzed. The morphological characteristics and CT values of the left CGs were recorded. The CT values of the ipsilateral adrenal gland (AG) and crus of the diaphragm (CD) were also measured. The left CG was located between the left AG and CD, and most CGs were long strips. The frequency of visualization of the left CGs was higher in the hypertension group than in the non‐hypertension group (p  .05). Except for the left CG in the arterial phase, the CT values of the left CG and AG in the non‐hypertensive group were higher than those in the hypertension group (p < .05). The venous phase enhancement of the left CG in the non‐hypertension group was significantly higher than that in the hypertension group (p < .05). Our findings reveal that CGs have characteristic manifestations in the hypertensive population. As important targets of the SNS, CGs have the potential to regulate blood pressure