Abstract
Electromechanical coupling factor,
k
, of piezoelectric materials determines the conversion efficiency of mechanical to electrical energy or electrical to mechanical energy. Here, we provide ...an fundamental approach to design piezoelectric materials that provide near-ideal magnitude of
k
, via exploiting the electrocrystalline anisotropy through fabrication of grain-oriented or textured ceramics. Coupled phase field simulation and experimental investigation on textured Pb(Mg
1/3
Nb
2/3
)O
3
-Pb(Zr,Ti)O
3
ceramics illustrate that
k
can reach same magnitude as that for a single crystal, far beyond the average value of traditional ceramics. To provide atomistic-scale understanding of our approach, we employ a theoretical model to determine the physical origin of
k
in perovskite ferroelectrics and find that strong covalent bonding between B-site cation and oxygen via
d
-
p
hybridization contributes most towards the magnitude of
k
. This demonstration of near-ideal
k
value in textured ceramics will have tremendous impact on design of ultra-wide bandwidth, high efficiency, high power density, and high stability piezoelectric devices.
The natural resonance appears at 16
GHz for (Fe, Ni)/C nanocapsules with (Fe, Ni) alloys as cores and graphite as shells. Reflection loss (RL) exceeding −10
dB was obtained in the whole Ku-band ...(12.4–18
GHz) for an absorber thickness of 2.0
mm, while it exceeds −20
dB over the 13.6–16.6
GHz range. In addition, the bandwidth does not change dramatically for the thicknesses of 1.87–2.1
mm for the RL values exceeding −10
dB. The (Fe, Ni)/C nanocapsules with wide bandwidth absorption can be used as excellent electromagnetic-wave-absorption materials in the whole Ku-band.
Graphite-coated FeNi alloy nanoparticles have been prepared by a modified arc-discharge method in an alcohol atmosphere and have been characterized by means of X-ray diffraction, energy dispersive ...spectroscopy, transmission electron microscopy, Raman spectroscopy, thermal gravimetric analysis and scanning differential thermal analysis. The results show that the nanoparticles have a core/shell structure, with FeNi alloy as core and graphite layers as shell. Compared with FeNi nanoparticles with an oxide shell, the graphite shell restricts the growth of the FeNi nanoparticles, which leads to lower saturation magnetization and higher natural-resonance frequency. Due to the enhancement of the thermal stability by the graphite shell and its oxidation protection, the graphite-coated FeNi nanoparticles are stable in air below 240
°C. The electromagnetic characteristics of the graphite-coated FeNi nanoparticles have been studied in the 2–18
GHz range. The graphite shell dramatically improves the magnetic/dielectric loss and the attenuation constant in the 9–18
GHz range through the enhancement of the electrical resistivity and the protection of the FeNi cores, leading to enhanced microwave-absorption properties in this range.
Whether ADC value predicts the therapy response and outcomes of primary central system lymphoma remains controversial. This study assessed the minimum ADC correlated with treatment response in ...patients with primary central nervous system lymphoma undergoing methotrexate-based chemotherapy.
Thirty-five patients with primary central nervous system lymphoma underwent conventional MR imaging and DWI before chemotherapy and after 1 and 5 cycles of chemotherapy. Treatment response was determined according to the International PCNSL Collaborative Group criteria and was classified as a complete response, partial response, or progressive disease. Pretreatment minimum ADC, minimum ADC after 1 cycle, minimum ADC after 5 cycles, and change in minimum ADC were compared among the different response groups. The Pearson correlation test was calculated between these ADC parameters and tumor response.
The pretreatment minimum ADC of the progressive disease group was lower than that of the complete response and partial response groups, but there was no significant difference among them. The minimum ADC after 1 cycle and minimum ADC after 5 cycles were statistically significantly higher than the pretreatment minimum ADC. A comparison among groups showed that minimum ADC after 1 cycle, minimum ADC after 5 cycles, minimum ADC change, and the percentage of minimum ADC change were all significantly different among the 3 groups. A significant positive correlation was observed between the percentage of minimum ADC after 1 cycle of chemotherapy and the size reduction percentage after 5 cycles of chemotherapy. The minimum ADC change and the percentage of minimum ADC change performed better in the differentiation of the final treatment response, specifically in complete response and partial response from progressive disease.
The minimum ADC after 1 cycle and minimum ADC changes were better correlated with the treatment response than the pretreatment minimum ADC. Minimum ADC after early therapy may potentially to be used to predict and monitor the response of primary central nervous system lymphoma to chemotherapy.
The Co-Pt binary system can form a two-phase nanochessboard structure comprising regularly aligned nanorods of magnetically hard tetragonal L10 phase and magnetically soft cubic L12 phase. This Co-Pt ...nanochessboard, being an exchange-coupled magnetic nanocomposite, exhibits a strong effect on magnetic domains and coercivity. While the ideal nanochessboard structure has tiles with equal edge lengths (a = b), the non-ideal or nonstandard nanochessboard structure has tiles with unequal edge lengths (a ≠ b). In this study, we employed phase-field modeling and computer simulation to systematically investigate the exchange coupling effect on magnetic properties in nonstandard nanochessboards. The simulations reveal that coercivity is dependent on the length scale, with magnetic hardening occurring below the critical exchange length, followed by magnetic softening above the critical exchange length, similar to the standard nanochessboards. Moreover, the presence of unequal edge lengths induces an anisotropic exchange coupling and shifts the coercivity peak with the length scale.
IDH1 mutational status probably plays an important role in the predictive response for patients with astroglioma. This study explores whether DTI metrics are able to noninvasively detect IDH1 status ...in astrogliomas.
The DTI data of 112 patients with pathologically proven astroglioma (including 25, 12, and 10 cases with IDH1 mutation and 11, 11, and 43 cases without mutation in grades II, III, and IV, respectively) were retrospectively reviewed. The maximal fractional anisotropy, minimal ADC, ratio of maximal fractional anisotropy, and ratio of minimal ADC in the tumor body were measured. In the same World Health Organization grading, the imaging parameters of patients with and without IDH1 R132H mutation were compared by means of optimal metrics for detecting mutations. Receiver operating characteristic curve analysis was performed.
The maximal fractional anisotropy and ratio of maximal fractional anisotropy values had statistical significance between patients with IDH1 R132H mutation and those without mutation in astrogliomas of grades II and III. The areas under the curve for maximal fractional anisotropy and ratio of maximal fractional anisotropy were both 0.92 in grade II and 0.80 and 0.82 in grade III. The minimal ADC value and ratio of minimal ADC value also demonstrated statistical significance between patients with mutation and those without mutation in all astroglioma grades. The areas under the curve for minimal ADC were 0.94 (II), 0.76 (III), and 0.66 (IV), and the areas under the curve for ratio of minimal ADC were 0.93 (II), 0.83 (III), and 0.70 (IV).
Fractional anisotropy and ADC from DTI can noninvasively detect IDH1 R132H mutation in astrogliomas.
The electrical modulation of magnetization through the magnetoelectric effect provides a great opportunity for developing a new generation of tunable electrical components. Magnetoelectric voltage ...tunable inductors (VTIs) are designed to maximize the electric field control of permeability. In order to meet the need for power electronics, VTIs operating at high frequency with large tunability and low loss are required. Here we demonstrate magnetoelectric VTIs that exhibit remarkable high inductance tunability of over 750% up to 10 MHz, completely covering the frequency range of state-of-the-art power electronics. This breakthrough is achieved based on a concept of magnetocrystalline anisotropy (MCA) cancellation, predicted in a solid solution of nickel ferrite and cobalt ferrite through first-principles calculations. Phase field model simulations are employed to observe the domain-level strain-mediated coupling between magnetization and polarization. The model reveals small MCA facilitates the magnetic domain rotation, resulting in larger permeability sensitivity and inductance tunability.
Hemodynamics factors play an important role in the rupture of cerebral aneurysms. The purpose of this study was to evaluate the impact of hemodynamic factors on the rupture of the MANs with 3D ...reconstruction model CFD simulation.
RDSA was performed in 9 pairs of intracranial MANs. Each pair was divided into ruptured and unruptured groups. The hemodynamic factors of the aneurysms and their parent arteries were compared.
There was a significant difference in the WSS at peak systole between the regions of the aneurysms and their parent arteries in the ruptured group (ie, 6.49 ± 3.48 Pa versus 8.78 ± 3.57 Pa, P =.015) but not in the unruptured group (ie, 9.80 ± 4.12 Pa versus 10.17 ± 7.48 Pa, P =.678). The proportion of the low WSS area to the whole area of the aneurysms was 12.20 ± 18.08% in the ruptured group and 3.96 ± 6.91% in the unruptured group; the difference between the 2 groups was statistically significant (P =.015). The OSI was 0.0879 ± 0.0764 in the ruptured group, which was significantly higher than that of the unruptured group (ie, 0.0183 ± 0.0191, P =.008).
MANs may be a useful disease model to investigate possible causes linked to ruptured aneurysms. The ruptured aneurysms manifested lower WSS compared with their parent arteries, a higher proportion of the low WSS area to the whole area of aneurysm, and higher OSI compared with the unruptured aneurysms.
We report a one-step approach for preparing dispersive CoxNi100-x nanoparticles completely encapsulated by curved graphite layers. The nanoparticles were prepared by evaporating Co-Ni alloys and the ...shell of graphite layers was formed by in situ metal-catalytic growth on the surface of nanoparticles whose layer number was controlled by tuning the Co content of the alloys. By modulating the composition of the magnetic core and the layer number of the shell, the magnetic and dielectric properties of these core/shell structures are simultaneously optimized and their permeability and permittivity were improved to obtain the enhanced electromagnetic match. As a result, the bandwidth of reflection loss (RL) exceeding -20 dB (99% absorption) of the nanocapsules is 9.6 GHz for S1, 12.8 GHz for S2, 13.5 GHz for S3 and 14.2 GHz for S4. The optimal RL value reaches -53 dB at 13.2 GHz for an absorber thickness of 2.55 mm. An optimized impedance match by controlling the growth of the core and shell is responsible for this extraordinary microwave absorption.
Introduction
To investigate the effect of zoledronic acid on periprosthetic bone mineral density (BMD) and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal ...osteoporosis.
Methods
From November 2015 to April 2016, 40 female patients who met the inclusion criteria were randomized into two groups: a control group (calcium + calcitriol) and a zoledronic acid group (calcium + calcitriol + zoledronic acid). At 1 week and 3, 6, and 12 months after operation, BMD was obtained through dual-energy X-ray absorptiometry (DEXA). At pre-operation and at 3, 6, and 12 months after the operation, levels of bone metabolism markers were obtained by serum examination.
Results
Loss of BMD was significantly more pronounced in the control group than in the ZOL group in zones 1, 4, 6, and 7 at 6 months and in zones 1, 2, 4, 6, and 7 at 12 months after the operation. The levels of bone-resorption marker (β-CTX) were significantly lower in the ZOL group than in the control group at 3, 6, and 12 months after operation. The levels of bone-formation marker (TP1NP) performed statistically differences only at 12 months after the operation in these two groups.
Conclusions
Receiving an intravenous infusion of 5 mg zoledronic acid after THA can effectively reduce periprosthetic BMD loss and improve bone remodeling in females with postmenopausal osteoporosis.
Summary
Zoledronic acid significantly inhibited bone mass loss in zones 1, 2, 4, 6, and 7 after THA and inhibited bone-resorption marker (β-CTX) to improve bone remodeling. Zoledronic acid treatment is potentially important for patients with osteoporosis after THA.
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