94 research outputs found
Angiosarcomas of the Bilateral Breast and Heart: Which One is the Primary Site?
A 29-year-old pregnant woman with recurrent pericardial effusion and a cardiac tumor, diagnosed as an angiosarcoma, was treated with surgical resection of the tumor followed by radiotherapy. Immediately after completion of radiotherapy, she developed bilateral breast masses, which were also confirmed as angiosarcomas. We thought this might be the first case of bilateral angiosarcoma of the breast metastasizing to heart mimicking a primary cardiac angiosarcoma, although we could not conclude with certainty that angiosarcoma of the heart was not the primary site
A Case of Histiocytic Sarcoma Presenting with Primary Bone Marrow Involvement
Histiocytic sarcoma (HS) is a very rare neoplasm that often shows an aggressive clinical course and systemic symptoms, such as fever, weight loss, adenopathy, hepatosplenomegaly and pancytopenia. It may present as localized or disseminated disease. We describe here a 63-yr-old male who manifested systemic symptoms, including fever, weight loss and generalized weakness. Abdominal and chest computed tomography failed to show specific findings, but there was suspicion of multiple bony changes at the lumbar spine. Fusion whole body positron emission tomography, bone scan and lumbar spine magnetic resonance imaging showed multiple bone lesions, suggesting a malignancy involving the bone marrow (BM). Several BM and bone biopsies were inconclusive for diagnosis. Necropsy showed replacement of the BM by a diffuse proliferation of neoplastic cells with markedly increased cellularity (95%). The neoplastic cells were positive for lysozyme and CD68, but negative for T- and B-cell lineage markers, and megakaryocytic, epithelial, muscular and melanocytic markers. Morphologic findings also distinguished it from other dendritic cell neoplasms
Reversibly controlled ternary polar states and ferroelectric bias promoted by boosting square???tensile???strain
Interaction between dipoles often emerges intriguing physical phenomena, such as exchange bias in the magnetic heterostructures and magnetoelectric effect in multiferroics, which lead to advances in multifunctional heterostructures. However, the defect-dipole tends to be considered the undesired to deteriorate the electronic functionality. Here, we report deterministic switching between the ferroelectric and the pinched states by exploiting a new substrate of cubic perovskite, BaZrO3, which boosts square-tensile-strain to BaTiO3 and promotes four-variants in-plane spontaneous polarization with oxygen vacancy creation. First-principles calculations propose a complex of an oxygen vacancy and two Ti3+ ions coins a charge-neutral defect-dipole. Cooperative control of the defect-dipole and the spontaneous polarization reveals ternary in-plane polar states characterized by biased/pinched hysteresis loops. Furthermore, we experimentally demonstrate that three electrically controlled polar-ordering states lead to switchable and non-volatile dielectric states for application of non-destructive electro-dielectric memory. This discovery opens a new route to develop functional materials via manipulating defect-dipoles and offers a novel platform to advance heteroepitaxy beyond the prevalent perovskite substrates
A novel high-entropy alloy with multi-strengthening mechanisms: Activation of TRIP effect in C-doped high-entropy alloy
© 2022 Elsevier B.V.Efforts have been made to intentionally activate multiple strengthening mechanisms in a single alloy because individual strengthening effects have not been sufficiently exhibited in previous alloys with multi-strengthening mechanisms. Here, we design a novel high-entropy alloy with multi-strengthening mechanisms through a stepwise design approach utilizing CALPHAD type thermodynamic calculation. The target strengthening mechanisms are introduced step by step, from solid solution strengthening, the addition of precipitation hardening and transformation-induced plasticity, based on the calculation. The finally designed Co21Cr11Fe49Mn4Ni4V2C1Mo3Si5 alloy simultaneously benefits from solid solution strengthening due to Mo and V addition, precipitation hardening from nanoscale precipitates, grain boundary strengthening by grain refinement, and transformation-induced plasticity by BCC deformation-induced martensite transformation. Individual strengthening effects is sufficiently exhibited in the designed alloy, which leads to an excellent combination of yield strength (732 MPa), ultimate tensile strength (1100 MPa), and ductility (47.5%).11Nsciescopu
Strength-ductility enhancement in multi-layered sheet with high-entropy alloy and high-Mn twinning-induced plasticity steel
In this study, a high-entropy-alloy-cored multi-layered sheet (MLS) clad with an austenitic high-Mn twinning-induced-plasticity steel (HEA/high-Mn MLS) is proposed and its room- and cryogenic-temperature tensile behaviors were investigated. The MLS was fabricated using a commercial roll-bonding procedure. Its interface was well bonded without critical defects such as pores or voids. During the MLS fabrication and subsequent annealing, the interdiffusion of alloying elements and interfacial friction resulted in the formation of epsilon-martensite and V-rich carbides in the high-Mn and HEA layers, respectively, as well as grain refinement. Nevertheless, the interface remained strongly bonded after the tensile deformation at room and cryogenic temperatures, thereby providing larger strength and elongation than the values calculated based on the rule of mixtures. The improvement in tensile properties beyond the calculated values was interpreted by the activation of deformation twins, transformation-induced plasticity, and generation of geometrically necessary dislocations in the HEA/high-Mn interfacial region. Deformation twins were populated at both high-Mn and HEA layers at room temperature. However, at cryogenic temperatures, epsilon-martensite and body-centered cubic martensite were additionally formed in the high-Mn and HEA layers. Thus, both strength and ductility were considerably improved. In addition, the consequent good strength-ductility balance was comparable to or better than those of other HEAs or medium-entropy alloys. This indicates that our MLS can be an attractive design strategy to tailor various properties by controlling the thickness fraction of each layer and develop strong alloys for cryogenic applications.11Nsciescopu
Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy: an atomistic simulation study
High entropy alloys: property prediction Atomistic calculations elucidate crucial strengthening mechanisms in high entropy alloys and predict better performing compositions. A team led by Byeong-Joo Lee at South Korea’s Pohang University of Science and Technology used various simulations techniques to study the movement of atoms in a series of disordered high entropy alloys. They attributed sluggish diffusion in the classic CoCrFeMnNi alloy to the large number of stable vacancy sites, and at cryogenic temperatures showed that micro-twinning was due to a more stable hexagonal crystal structure. Finally, they used their simulation results to predict the effect of alloying on the critical resolved shear stress and designed a high entropy alloy with improved properties. A computational approach to the design of high entropy alloys may thus help us develop more complex alloys and tailor their properties
Doubled strength and ductility via maraging effect and dynamic precipitate transformation in ultrastrong medium-entropy alloy
Commercial maraging alloys provide high strength and toughness by traditional precipitation strengthening mechanism. Here, the authors demonstrate a new strategy involving deformable precipitates and their dynamic phase transformation resulting in a twofold enhancement of strength and ductility
W,Nb and Cr Effects on High-temperature Tensile properties in Heat- resistant Austenitic Cast Steels
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