Aim To examine the differential features of mass-forming intrahepatic cholangiocarcinoma (ICC) from atypical hypovascular hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced magnetic resonance ...imaging (MRI). Materials and methods The institutional review board approved this retrospective study and waived informed patient consent. Seventy patients with pathologically proven ICCs (35) and hypovascular atypical HCCs (35) who had undergone preoperative gadoxetic acid-enhanced MRI were enrolled in this study. Images were analysed for the shape of the lesions and presence of hyperintensity on the T1-weighted image (T1WI) and hypo- or hyperintense areas on the T2-weighted image (T2WI). In addition, images were analysed for the presence of linear hyperintensity or multifocal, tiny, hyperintense foci on T2WI and the presence of rim enhancement during early dynamic phases and a central enhancement with a hypointense rim (target appearance) on the 10 and 20 min hepatobiliary phase images. The significance of these findings was determined by the X2 test. Results Univariate analysis revealed that the following significant parameters favour ICC or hypovascular HCC; the presence of T2 hypo- and hyperintense areas and target appearance on the 10 min hepatobiliary phase images favour ICC, and the presence of T2 linear hyperintensity and T2 multifocal hyperintense foci favour hypovascular HCC ( p < 0.05). Multivariate analysis revealed that only target appearance on the 10 min hepatobiliary phase was predictive of ICC ( p = 0.002) as 30 ICCs (85.7%) showed this feature. However, the target appearance was also observed in all six scirrhous HCCs. Conclusion A target appearance on the 10 min hepatobiliary phase images is the best predictor for identifying mass-forming ICC at gadoxetic acid-enhanced MRI.
A missense somatic mutation in JAK2 gene (JAK2 V617F) has recently been reported in chronic myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and myelofibrosis with ...myeloid metaplasia, strongly suggesting its role in the pathogenesis of myeloid disorders. As activation of JAK2 signaling is occurred in other malignancies as well, we have analysed 558 tissues from common human cancers, including colon, breast and lung carcinomas, and 143 acute adulthood leukemias by polymerase chain reaction -- single strand conformation polymorphism analysis. We found three JAK2 mutations in the 113 acute myelogenous leukemias (AMLs) (2.7%), but none in other cancers. The mutations consisted of two V617F mutations and one K607N mutation. None of the AML patients with the JAK2 V617F mutation had a history of previous hematologic disorders. This is the first report on the JAK2 gene mutation in AML, and the data indicated that the JAK2 gene mutation may not only contribute to the development of chronic myeloid disorders, but also to some AMLs.
In clean inversion symmetric materials, spin-orbit coupling is not thought to have a pronounced effect on spin-singlet superconductivity. Here we show that, for the recently discovered pnictide ...superconductor SrPtAs, this is not the case. In particular, for spin-singlet superconductivity in SrPtAs, strong spin-orbit coupling leads to a significant enhancement of both the spin susceptibility and the paramagnetic limiting field with respect to that usually expected for spin-singlet superconductors. The underlying reason for this is that, while SrPtAs has a center of inversion symmetry, it contains weakly coupled As-Pt layers that do not have inversion symmetry. This local inversion-symmetry breaking allows for a form of spin-orbit coupling that dramatically effects superconductivity. These results indicate that caution should be used when interpreting measurements of the spin susceptibility and the paramagnetic limiting field if superconductivity resides in regions of locally broken inversion symmetry.
Using scanning tunneling microscopy with Fe-coated W tips and first-principles calculations, we show that the interface of epitaxial graphene/SiC(0001) is a warped graphene layer with ...hexagon-pentagon-heptagon (H(5,6,7)) defects that break the honeycomb symmetry, thereby inducing a gap and states below E(F near the K point. Although the next graphene layer assumes the perfect honeycomb lattice, its interaction with the warped layer modifies )the dispersion about the Dirac point. These results explain recent angle-resolved photoemission and carbon core-level shift data and solve the long-standing problem of the interfacial structure of epitaxial graphene on SiC(0001).
SnSe has been widely studied due to its many potential applications that take advantage of its excellent thermoelectric, photovoltaic, and optoelectronic properties. However, experimental ...investigations into the microscopic structure of SnSe remain largely unexplored. Herein, for the first time, the atomic and electronic structures of SnSe surfaces are studied by a home-built low temperature scanning tunneling microscope (STM) and density functional theory (DFT) calculations. The cleaved surface of SnSe is comprised of covalently bonded Se and Sn atoms in zigzag patterns. However, rectangular periodicity was observed in the atomic images of SnSe surfaces for filled and empty state probing. Detailed atomic structures are analyzed by DFT calculations, indicating that the bright extrusions of both filled and empty state images are mostly located at the positions of Sn atoms.
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•The atomic and electronic structures of SnSe surfaces are studied by a home-built LT-STM and DFT calculations.•Clear atomic images of cleaved SnSe surfaces were observed at the filled and empty state measurements.•The atomic structures revealed the periodicity of a rectangular unit cell, and detail structures were analyzed based on DFT.•Only Sn atoms are visible on STM topographic images for both filled and empty state probing.
In this study, density functional calculations are performed on magnetocrystalline anisotropy (MCA) of hcp and fcc Co films to reveal influence of symmetry, thickness, and surface. First, MCA of bulk ...is revisited. MCA energy (EMCA) of hcp is 15.61 μeV/atom, two orders of magnitude larger than 0.53 μeV/atom of fcc Co. Smaller EMCA of fcc Co originates from the negative contributions from the highly peaked unoccupied minority |m|=1 states at Fermi level (EF). In Co films, EMCA is significantly enhanced to 175.90 and 211.48 μeV/atom at both hcp and fcc surfaces, resulting in the same order of magnitude for both the films. Substantial EMCA enhancement stems from the increased occupied and unoccupied minority |m|=2 states located very close to EF. Strong EMCA oscillation with thickness is observed for less than 10 monolayers, whose origin comes from the quantum well |m|=1 states at EF.
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•In bulk, MCA energy of hcp Co is two orders of magnitude larger than that of fcc Co.•In thin film, substantial MCA energy at the surface results in the same order of magnitude between hcp and fcc Co.•Strong oscillatory behavior of MCA energy as a function of thickness is observed for thicknesses less than 10 ML.
Minor recanalization in coiled aneurysms may remain stable with time or may progress to major recanalization. Our aim was to monitor the aneurysms displaying minor recanalization in imaging studies ...at 6 months, gauging major recanalization rates and related risk factors through extended follow-up.
Sixty-five aneurysms (in 65 patients) showing minor recanalization in follow-up imaging at 6 months were reviewed retrospectively. Medical records and radiologic data accruing during extended monitoring (mean, 24.8 ± 8.2 months) were assessed. Univariate and multivariate analyses were conducted to identify risk factors for progression from minor-to-major recanalization.
Progression to major recanalization was observed in 24 (36.9%) of the initially qualifying aneurysms during a follow-up of 112.5 aneurysm-years, for an annual rate of 17.84% per aneurysm-year. Progression was determined chronologically as follows: 14 (58.3%) at 6 months, 8 (33.3%) at 18 months, and 2 (8.4%) at 30 months. Stent deployment significantly decreased the occurrence of major recanalization (OR = 0.22, P = .03), whereas antiplatelet therapy (OR = 0.82, P = .75), posterior location (OR = 0.24, P = .20), and second coiling for recanalized aneurysms (OR = 0.96, P = .96) were unrelated.
Our analysis determined a 36.9% rate of major recanalization during a follow-up of 112.5 aneurysm-years in coiled aneurysms showing minor recanalization at 6 months. Stent deployment alone conferred a protective effect, preventing further recanalization without additional treatment. Given the fair probability of late major recanalization, aneurysms showing minor recanalization at 6 months should be monitored diligently, particularly in the absence of stent placement.
A key challenge in manipulating the magnetization in heavy-metal/ferromagnetic bilayers via the spin-orbit torque is to identify materials that exhibit an efficient charge-to-spin current conversion. ...Ab initio electronic structure calculations reveal that the intrinsic spin Hall conductivity (SHC) for pristine β-W is about 60% larger than that of α-W. More importantly, we demonstrate that the SHC of β-W can be enhanced via Ta alloying. This is corroborated by spin Berry curvature calculations of W1−xTax (x∼12.5%) alloys which show a giant enhancement of the spin Hall angle of up to ≈−0.5. The underlying mechanism is the synergistic behavior of the SHC and longitudinal conductivity with the Fermi level position. These findings not only pave the way for enhancing the intrinsic spin Hall effect in β-W, but also provide guidelines to exploit substitutional alloying to tailor the spin Hall effect in various materials.
A two-dimensional system in a curved geometry is investigated in the framework of general relativity. We show that the non-vanishing curvature, which is inevitable from the curved geometry, opens a ...band gap, which is commonly interpreted as a pseudo-magnetic field. Furthermore, the size of the gap is proportional to the square root of the curvature, which is of order of a few meV for an Å-scale deformation with respect to a hundreds of A scale lateral size. The spectra modified by the curvature are obtained in a perturbative way from the pole structure of the propagator.
Significant enhancement of the magnetocrystalline anisotropy (MCA) of an Fe(001) surface capped by 4d and 5d transition metal monolayers is presented in this study using first principles density ...functional calculations. In particular, an extremely large perpendicular MCA of +10 meV/Ir was found in Ir-capped Fe(001), which originates not from the Fe but from the large spin-orbit coupling of the Ir atoms. From the spin-channel decomposition of the MCA matrix and electronic structure analyses, we find that strong 3d-5d band hybridization in the minority spin state is responsible for the sign changes of the MCA from parallel to perpendicular.
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