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Undifferentiated pleomorphic sarcoma (UPS) is the largest subgroup of soft tissue sarcomas. This study determined the value of perfusion-weighted imaging with dynamic-contrast-enhancement (PWI/DCE) morphologic, qualitative, and semiquantitative features for predicting UPS pathology-assessed treatment effect (PATE). This retrospective study included 33 surgically excised extremity UPS patients with pre-surgical MRI. Volumetric tumor segmentation from PWI/DCE was obtained at Baseline (BL), Post-Chemotherapy (PC), and Post-Radiation Therapy (PRT). The surgical specimens’ PATE separated cases into Responders (R) (≥ 90%, 16 patients), Partial-Responders (PR) (89 − 31%, 10 patients), and Non-Responders (NR) (≤ 30%, seven patients). Seven semiquantitative kinetic parameters and maps were extracted from time-intensity curves (TICs), and 107 radiomic features were derived. Statistical analyses compared R vs. PR/NR. At PRT, 79% of R displayed a “Capsular” morphology (P = 1.49 × 10-7), and 100% demonstrated a TIC-type II (P = 8.32 × 10-7). 80% of PR showed “Unipolar” morphology (P = 1.03 × 10-5), and 60% expressed a TIC-type V (P = 0.06). Semiquantitative wash-in rate (WiR) was able to separate R vs. PR/NR (P = 0.0078). The WiR radiomics displayed significant differences in the first_order_10 percentile (P = 0.0178) comparing R vs. PR/NR at PRT. The PWI/DCE TIC-type II curve, low WiR, and “Capsular” enhancement represent PRT patterns typically observed in successfully treated UPS and demonstrate potential for UPS treatment response assessment. [ABSTRACT FROM AUTHOR]

Summary: We propose a combined nodal integration and virtual element method for compressible and nearly incompressible elasticity, wherein the strain is averaged at the nodes from the strain of surrounding virtual elements. For the strain averaging procedure, a nodal averaging operator is constructed using a generalization to virtual elements of the node‐based uniform strain approach for finite elements. We refer to the proposed technique as the node‐based uniform strain virtual element method (NVEM). No additional degrees of freedom are introduced in this approach, thus resulting in a displacement‐based formulation. A salient feature of the NVEM is that the stresses and strains become nodal variables just like displacements, which can be exploited in nonlinear simulations. Through several benchmark problems in compressible and nearly incompressible elasticity as well as in elastodynamics, we demonstrate that the NVEM is accurate, optimally convergent and devoid of volumetric locking. [ABSTRACT FROM AUTHOR]

The October 2020 Virtual Symposium by the International Atmospheric Rivers Conference What: Despite the COVID-19 pandemic, the science of atmospheric rivers was well served by the organization of a virtual symposium joined by more than 100 researchers. In addition to conveying new science, significant lessons were learned on how to run virtual events. When: 5-9 October 2020 Where: Online. [ABSTRACT FROM AUTHOR]

Summary: In this article, we present a novel nodal integration scheme for meshfree Galerkin methods, which draws on the mathematical framework of the virtual element method. We adopt linear maximum‐entropy basis functions for the discretization of field variables, although the proposed scheme is applicable to any linear meshfree approximant. In our approach, the weak form integrals are nodally integrated using nodal representative cells that carry the nodal displacements and state variables such as strains and stresses. The nodal integration is performed using the virtual element decomposition, wherein the bilinear form is decomposed into a consistency part and a stability part that ensure consistency and stability of the method. The performance of the proposed nodal integration scheme is assessed through benchmark problems in linear and nonlinear analyses of solids for small displacements and small‐strain kinematics. Numerical results are presented for linear elastostatics and linear elastodynamics and viscoelasticity. We demonstrate that the proposed nodally integrated meshfree method is accurate, converges optimally, and is more reliable and robust than a standard cell‐based Gauss integrated meshfree method. [ABSTRACT FROM AUTHOR]

This paper summarizes the development of Veamy, an object-oriented C++ library for the virtual element method (VEM) on general polygonal meshes, whose modular design is focused on its extensibility. The linear elastostatic and Poisson problems in two dimensions have been chosen as the starting stage for the development of this library. The theory of the VEM, upon which Veamy is built, is presented using a notation and a terminology that resemble the language of the finite element method (FEM) in engineering analysis. Several examples are provided to demonstrate the usage of Veamy, and in particular, one of them features the interaction between Veamy and the polygonal mesh generator PolyMesher. A computational performance comparison between VEM and FEM is also conducted. Veamy is free and open source software. [ABSTRACT FROM AUTHOR]

Presents a study on the effects of grain size distribution on the magnetization curve of polycrystalline ferrimagnets. Background on grain size distribution; Steps and equations necessary for the prediction of magnetization; Discussion on the Gobus model for magnetization mechanisms in polycrystalline ferrites.

Examines the effects of thermal annealing on the frequency behavior the initial permeability of Vitrovac amorphous ribbons. Details on the experiments; Results of the study; Conclusion.

Magnetite nanoparticles about 10 nm sized were synthesized by the polyol method. Zero-field-cooled (ZFC)-FC measurements showed a blocking temperature ~170K and the absence of the Verwey transition. They were subsequently consolidated by spark plasma sintering at 750 °C for 15 min, leading to a high density (92% of the theoretical density), solid body, with grains in the 150 nm range. X-ray diffraction patterns exhibited a spinel single phase with cell parameters corresponding to the magnetite structure. Magnetic measurements showed a decrease of coercivity from 685 Oe (54.5 kA/m) at 118K to 90 Oe (7.2 kA/m) at 139 K. ZFC measurements at 25 Oe presented a three-fold magnetization increase as temperature increased; a small transition between 116 and 117.5 K, followed by a larger one from 117.6 to 124 K. The first transition can be associated with a complex crystallographic transition and delocalization of Fe2+-Fe3+, while the second one can be attributed to spin reorientation due to the magnetocrystalline anisotropy constant (K1) change of sign as previously observed only in magnetite single crystals. [ABSTRACT FROM AUTHOR]

Barium hexaferrite (BaFeO) ceramics were obtained by combination of polyol-synthesized precursors subsequently consolidated by spark plasma sintering (SPS) at a low temperature (800 C). X-ray powder diffraction studies showed the influence of the experimental parameters to produce a virtually single- or multiphase material. The room temperature magnetic properties exhibited interesting variety of properties, including exchange coupling (spring magnet) between hexaferrite and other magnetic phases. The saturation magnetization and coercive field, at room temperature, are in the 34-70 emu/g and 4.1-5.0 kOe ranges, respectively. The combination of strong coercive field and magnetization resulted in a maximum energy product [(BH)max] = 10.9 kJ/m for the sample with the highest BaFeO content. [ABSTRACT FROM AUTHOR]

In this report we present a study of the magnetization processes for Co-based amorphous ribbons at low frequencies (10 Hz-13 MHz) as a function of decreasing thicknesses attained by chemical etching. Reversible domain-wall bulging, characterized by initial permeability and relaxation frequency, was monitored by means of inductance measurements. The real part of inductance sproportional to initial permeabilityd exhibited a decreasing trend with diminishing ribbon thickness, together with an increasing tendency for the relaxation frequency. For high amplitude of the ac field sleading to domain-wall unpinningd, reduced ribbon thickness showed a deleterious-enhancement effect on irreversible domain-wall displacement, which was observed for both real and imaginary inductance spectrocopic plots. Results are interpreted in terms of reduced domain-wall pinning distances resulting from thinner alloy samples. [ABSTRACT FROM AUTHOR]

Complex inductance formalism (L) is used to calculate the complex circular permeability (μ[SUBcirc) in a domain model for the magnetoimpedance (MI) of soft ferromagnetic wires. An excellent agreement between calculated and experimental values of μ[SUBcirc] as a function of frequency is observed. In addition, a very good agreement is also exhibited between experimental and calculated plots of μ[SUBcirc] as a function of an applied dc magnetic field before and above the relaxation frequency (also known as single- and double-peak MI effect). These results confirm the validity of L as an alternative approach to MI phenomena in soft ferromagnetic wires. [ABSTRACT FROM AUTHOR]

A systematic study of die-cast REFeAl (RE = Nd + Pr) bulk amorphous alloys with small B, Cu, and Dy additions is presented. Differential scanning calorimetry and x-ray diffraction data are consistent with an amorphous microstructure and a small amount of hcp Nd-type crystallites embedded in the amorphous matrix for B, Cu+ B-, and Dy-containing alloys. Coercivity, H[SUBc], exhibits a progressive enhancement upon B, B+ Cu, and Dy addition (from 284 kA/m for Nd[SUB30]Fe[SUB60]Al[SUB10] up to 388 kA/m for Dy substituted alloy). This H[SUBc] improvement is associated not only with domain wall pinning on the crystallites, but also with the increase of nucleation sites and thus, with the number of RE and RE-Fe-Al clusters. In agreement with the latter, a superparamagnetic behavior, which is characteristic of a clustered structure, was observed above 451 K for all the alloy compositions. [ABSTRACT FROM AUTHOR]

The magnetoimpedance (MI) effect is based on the change of inductance and resistance under the effect of an external magnetic field. In bulk homogeneous wires or ribbons these two components of the impedance are related to the penetration depth of the electromagnetic field in the material. From simple considerations it is shown that the maximum MI ratio is then proportional to the square root of the relative permeability of the material. That limit is reached for frequencies at which the penetration depth is of the order of the transverse dimensions of the sample. At low operating frequencies, typical of thick geometries, the permeability is limited by the microeddy currents associated with domain wall displacements. The permeability relaxation equivalent to these local eddy currents can be calculated and used in the classical expressions for MI. The real part of the permeability is highly reduced at the relaxation frequency and gives rise to a decrease of the inductance, while the imaginary part contributes to the resistance, with a maximum at the same frequency. [ABSTRACT FROM AUTHOR]

A systematic study of the complex inductance response and the giant magnetoimpedance effect of as-cast CoFeBSiMoNi microwires (30 µm diameter) as a function of frequency (100 Hz-13 MHz) and circular field amplitude (21-212 A/m rms on the wire's surface) is presented. The microwire magnetization mechanisms are discussed in terms of complex inductance plots (in both real and imaginary parts). The analysis of the experimental results showed evidence of pinning, bulging, and displacement of circumferential domain walls. Higher relaxation frequencies together with a larger unpinning field (3-5 × 10[sup 6] Hz and 127 A/m, respectively), compared with conventional amorphous wires, were explained in terms of the reduced dimension of the microwire. Total impedance plots as a function of a bias H[sub dc] field showed an asymmetric character associated with an induced anisotropy during the wire fabrication. [ABSTRACT FROM AUTHOR]

A detailed study of the complex inductance response of as-cast CoFeBSi wires as a function of frequency (100 Hz–13 MHz range) and circular field amplitude [0.1–17 A/m room mean square (rms) on the surface of the wire] in the giant magnetoimpedance arrangement is presented. The analysis of experimental results show evidence of magnetization processes associated with circumferential domain walls, such as domain wall pinning, bulging, and displacement. The unpinning field was measured as 0.2 A/m (rms) at 5 kHz. It is shown that the analysis of spectroscopic plots of real and imaginary inductance leads to characterization of the magnetization process involved. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Impedance spectroscopy measurements were carried out on amorphous ribbons of nominal compositions Fe[sub 93-x-y]Zr[sub 7]B[sub x]Cu[sub y] (x=6,8 and y=0,1,2), in the frequency range of 5 Hz–13 MHz. Two different geometries were used for measurements: a longitudinal one by using an 80-turn solenoid and the magnetoimpedance geometry, where the ac current flows through the ribbon itself. The obtained results showed a larger initial permeability value for longitudinal domain walls, as compared with transverse ones. Results concerning the propagation field showed the opposite behavior. These results are interpreted in terms of the short-range order arrangements of Fe atoms in these alloys, also known as “nanoamorphous demixing structures.” © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Studies the measurements of monodomain, polycystalline hexagonal ferrites and amorphous ribbons. Information on the magnetization mechanism at low measuring frequencies in polycrystalline ferrites; Details on the experimental techniques; Experimental results.

Studies the temperature dependence of the critical magnetic field in Vitrovac-type magnetic amorphous ribbons. Use of polycrystalline nickel ferrite; General behavior of the critical fields as a function of temperature; Effect of nucleation and crystallization phenomena on the high-temperature behavior of the critical field.

Focuses on a study which extended the domain wall size model of polycrystalline ferrimagnetics to the case of ferromagnetic amorphous ribbons. Role played by surface pinning; Assumption on the function of magnetization; Focus of the function of the domain wall size model; Mechanisms proposed to account for pinning phenomena in amorphous ribbons.

Presents information on a study which showed that the thermal dependence of the critical magnetic field can be given in terms of the saturation magnetization and the initial magnetic permeability. Experimental procedure; Results and discussion.

Presents a dc electric current sensor based on the magnetoimpedance phenomenon. Flow of dc current through a solenoid; Magnetic field produced by solenoid; Thermal stability, reproducibility and wire contact preparation of the sensor.

Deals with a study which aimed to contribute to the understanding of changes introduced by current annealings in the domain structure of the wire then analyzing their impedance response. Experimental techniques; Experimental results; Discussion and conclusions.

Focuses on a study which presented a magnetic-field sensor based on the giant magnetoimpedance phenomenon. Description of the phenomenon giant magnetoimpedance; Details of the experimental technique; Discussion on the use of magnetorestriction cobalt iron boron silicon amorphous wire as a movement detector.

Deals with a study which investigated the magnetoimpedance in arsenic-cast nonmagnetoresistive CoFeBSi amorphous ferromagnetic wires. Preparation of the study samples; Analysis of the behavior of a ferromagnetic wire submitted to an alternating current; Results and discussion.

Presents a study which examined the effects of nanocrystallization upon the soft magnetic properties of Co-based amorphous alloys. Initial permeability as a function of time for three annealing temperatures; Domain wall relaxation frequency as a function of time for three annealing temperatures; Transmission electron microscopy image and electron diffraction pattern for annealing 20 minutes at 693 K.

Deals with a study which measured the equation of motion for ferromagnetic domain walls with initial permeability measurements of cobalt-based soft ferromagnetic amorphous ribbons. Experimental details; Experimental results; Discussion; Conclusions.

High circulating nonesterified fatty acids (NEFAs) concentration, often reported in diabetes, leads to impaired glucose-stimulated insulin secretion (GSIS) through not yet well-defined mechanisms. Serotonin and dopamine might contribute to NEFA-dependent β-cell dysfunction, since extracellular signal of these monoamines decreases GSIS. Moreover, palmitate-treated β-cells may enhance the expression of the serotonin receptor Htr2c, affecting insulin secretion. Additionally, the expression of monoamine-oxidase type B (Maob) seems to be lower in islets from humans and mice with diabetes compared to nondiabetic islets, which may lead to increased monoamine concentrations. We assessed the expression of serotonin- and dopamine-related genes in islets from db/db and wild-type (WT) mice. In addition, the effect of palmitate and oleate on the expression of such genes, 5HT content, and GSIS in MIN6 β-cell was determined. Lower Maob expression was found in islets from db/db versus WT mice and in MIN6 β-cells in response to palmitate and oleate treatment compared to vehicle. Reduced 5HT content and impaired GSIS in response to palmitate (−25%; p<0.0001) and oleate (−43%; p<0.0001) were detected in MIN6 β-cells. In conclusion, known defects of GSIS in islets from db/db mice and MIN6 β-cells treated with NEFAs are accompanied by reduced Maob expression and reduced 5HT content. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Médica MD is the property of Comite Editorial de la Revista Medica MD and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)