446 research outputs found

    Improvements in diagnosis have changed the incidence of histological types in advanced gastric cancer.

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    The data on 912 patients with early cancer and 1245 with advanced cancer who were seen between 1971 and 1990 were compared. The incidence of undifferentiated-type cancer increased significantly in patients with advanced gastric cancer, but not in patients with early gastric cancer. When the histological types were compared with regard to sex, age and location in patients with early gastric cancer the undifferentiated type was found to increase only in males, while in patients with advanced gastric cancer the undifferentiated type increased in both sexes as well as in younger patients and in both the upper and middle third of the stomach. These differences in the trends between early and advanced cancers are probably due to the different degrees of diagnostic accuracy for the early detection of histological types

    Layer dependent band dispersion and correlations using tunable Soft X-ray ARPES

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    Soft X-ray Angle-Resolved Photoemission Spectroscopy is applied to study in-plane band dispersions of Nickel as a function of probing depth. Photon energies between 190 and 780 eV were used to effectively probe up to 3-7 layers. The results show layer dependent band dispersion of the Delta_2 minority-spin band which crosses the Fermi level in 3 or more layers, in contrast to known top 1-2 layers dispersion obtained using ultra-violet rays. The layer dependence corresponds to an increased value of exchange splitting and suggests reduced correlation effects in the bulk compared to the surface.Comment: 7 pages, 3 figures Revised text and figur

    Temperature dependent Eu 3d-4f X-ray Absorption and Resonant Photoemission Study of the Valence Transition in EuNi2(Si0.2Ge0.8)2EuNi_2(Si_{0.2}Ge_{0.8})_2

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    We study the mixed valence transition (TTv_{v} ∼\sim80 K) in EuNi2_{2}(Si0.2_{0.2}Ge0.8_{0.8})2_{2} using Eu 3d−4fd-4f X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy (RESPES). The Eu2+^{2+} and Eu3+^{3+} main peaks show a giant resonance and the spectral features match very well with atomic multiplet calculations. The spectra show dramatic temperature (TT)-dependent changes over large energies (∼\sim10 eV) in RESPES and XAS. The observed non-integral mean valencies of ∼\sim2.35 ±\pm 0.03 (TT = 120 K) and ∼\sim2.70 ±\pm 0.03 (TT = 40 K) indicate homogeneous mixed valence above and below TTv_{v}. The redistribution between Eu2+^{2+}4f74f^7+[spd]0[spd]^0 and Eu3+^{3+}4f64f^6+[spd]1[spd]^1 states is attributed to a hybridization change coupled to a Kondo-like volume collapse.Comment: 4 pages, 3 figure

    Bulk screening in core level photoemission from Mott-Hubbard and Charge-Transfer systems

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    We report bulk-sensitive hard X-ray (hνh\nu = 5.95 KeV) core level photoemission spectroscopy (PES) of single crystal V1.98_{1.98}Cr0.02_{0.02}O3_{3} and the high-TcT_c cuprate Bi2_2Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} (Bi2212). V1.98_{1.98}Cr0.02_{0.02}O3_{3} exhibits low binding energy "satellites" to the V 2p2p "main lines" in the metallic phase, which are suppressed in the antiferromagnetic insulator phase. In contrast, the Cu 2p2p spectra of Bi2212 do not show temperature dependent features, but a comparison with soft X-ray PES indicates a large increase in the 2p53d92p^5 3d^9 "satellites" or 3d93d^9 weight in the bulk. Cluster model calculations, including full multiplet structure and a screening channel derived from the coherent band at the Fermi energy, give very satisfactory agreement with experiments

    Impact Ionization in ZnS

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    The impact ionization rate and its orientation dependence in k space is calculated for ZnS. The numerical results indicate a strong correlation to the band structure. The use of a q-dependent screening function for the Coulomb interaction between conduction and valence electrons is found to be essential. A simple fit formula is presented for easy calculation of the energy dependent transition rate.Comment: 9 pages LaTeX file, 3 EPS-figures (use psfig.sty), accepted for publication in PRB as brief Report (LaTeX source replaces raw-postscript file

    The effect of synthetic octacalcium phosphate in a collagen scaffold on the osteogenicity of mesenchymal stem cells

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    Although the efficacy of the in vivo osteogenic capabilities of synthetic octacalcium phosphate (OCP) crystal implantation can be explained through its stimulatory capacity for the differentiation of the host osteoblastic cell lineage, direct evidence that OCP supports bone regeneration by osteogenic cells in vivo has not been shown. Mesenchymal stem cells (MSCs) isolated from 4-week-old male Wistar rat long bones were pre-incubated in osteogenic or maintenance medium in the presence or absence of basic fibroblast growth factor (bFGF). OCP/Collagen (OCP/Col) or collagen disks were seeded with MSCs that had been pre-incubated in osteogenic medium containing bFGF, which exhibited the highest differentiation induction, and then incubated for an additional day. The disks were implanted in critical-sized calvaria defects of 12-week-old male Wistar rats and the specimens were analysed radiographically, histologically, histomorphometrically, and by micro-computed tomography (CT) imaging at 4 and 8 weeks after the implantation. The OCP/Col·MSCs group rapidly induced more bone regeneration, even within 4 weeks, compared to the OCP/Col group without MSCs. The bone mineral density of the OCP/Col·MSCs group was also greater than the OCP/Col group. The Col·MSCs group did not exhibit prominent osteogenicity. These results indicate that OCP crystals in a collagen matrix efficiently promote exogenously introduced osteogenic cells to initiate bone regeneration if the cells are pre-treated in a suitable differentiation condition

    Incorporating latent variables using nonnegative matrix factorization improves risk stratification in Brugada syndrome

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    Background: A combination of clinical and electrocardiographic risk factors is used for risk stratification in Brugada syndrome. In this study, we tested the hypothesis that the incorporation of latent variables between variables using nonnegative matrix factorization can improve risk stratification compared with logistic regression. Methods and Results: This was a retrospective cohort study of patients presented with Brugada electrocardiographic patterns between 2000 and 2016 from Hong Kong, China. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation. The external validation cohort included patients from 3 countries. A total of 149 patients with Brugada syndrome (84% males, median age of presentation 50 [38–61] years) were included. Compared with the nonarrhythmic group (n=117, 79%), the spontaneous ventricular tachycardia/ ventricular fibrillation group (n=32, 21%) were more likely to suffer from syncope (69% versus 37%, P=0.001) and atrial fibrillation (16% versus 4%, P=0.023) as well as displayed longer QTc intervals (424 [399–449] versus 408 [386–425]; P=0.020). No difference in QRS interval was observed (108 [98–114] versus 102 [95–110], P=0.104). Logistic regression found that syncope (odds ratio, 3.79; 95% CI, 1.64–8.74; P=0.002), atrial fibrillation (odds ratio, 4.15; 95% CI, 1.12–15.36; P=0.033), QRS duration (odds ratio, 1.03; 95% CI, 1.002–1.06; P=0.037) and QTc interval (odds ratio, 1.02; 95% CI, 1.01–1.03; P=0.009) were significant predictors of spontaneous ventricular tachycardia/ventricular fibrillation. Increasing the number of latent variables of these electrocardiographic indices incorporated from n=0 (logistic regression) to n=6 by nonnegative matrix factorization improved the area under the curve of the receiving operating characteristics curve from 0.71 to 0.80. The model improves area under the curve of external validation cohort (n=227) from 0.64 to 0.71. Conclusions: Nonnegative matrix factorization improves the predictive performance of arrhythmic outcomes by extracting latent features between different variables

    Role of Ag doping in Ba8Si46 compounds

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    The silicon clathrate compound Ba8Si46 shows superconductivity below the critical temperature (Tc) of 8K, and the Tc decreases monotonically with doping Ag. In order to reveal effects of Ag doping on the electronic states, we have applied soft x-ray photoemission spectroscopy to Ag-doped silicon clathrate compounds Ba8AgxSi46-x (x=0,1,3,6). The valence band photoemission spectra show that a Ba 5d-derived state at the Fermi level (EF), which is prominently observed in Ba8Si46, decreases with increasing Ag content. The reduction in the peak intensity at EF with increasing Ag content is therefore in accord with the decrease of Tc in Ba8AgxSi46-x. Band structure calculation using local-density approximation reproduces the observed valence band spectra of x=0 and 6. The Si 2p and Ba 4d core-level photoemission spectra demonstrate that the valence electron of Si is attracted to the Ag site in x=1 and the 5d electron of Ba inside the Si24 cage is further donated to Ag in x≥3. Hence, Ag doping leads to the reduction of the peak at EF

    Bulk Electronic structure of Na0.35_{0.35}CoO2_{2}.1.3H2_{2}O

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    High-energy (hν\nu = 5.95 keV) synchrotron Photoemission spectroscopy (PES) is used to study bulk electronic structure of Na0.35_{0.35}CoO2_{2}.1.3H2_{2}O, the layered superconductor. In contrast to 3-dimensional doped Co oxides, Co 2p\it{2p} core level spectra show well-separated Co3+^{3+} and Co4+^{4+} ions. Cluster calculations suggest low spin Co3+^{3+} and Co4+^{4+} character, and a moderate on-site Coulomb correlation energy Udd∼_{dd}\sim3-5.5 eV. Photon dependent valence band PES identifies Co 3d\it{3d} and O 2p\it{2p} derived states, in near agreement with band structure calculations.Comment: 4 pages 4 figures Revised text added referenc

    GRAB: A Dataset of Whole-Body Human Grasping of Objects

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    Training computers to understand, model, and synthesize human grasping requires a rich dataset containing complex 3D object shapes, detailed contact information, hand pose and shape, and the 3D body motion over time. While "grasping" is commonly thought of as a single hand stably lifting an object, we capture the motion of the entire body and adopt the generalized notion of "whole-body grasps". Thus, we collect a new dataset, called GRAB (GRasping Actions with Bodies), of whole-body grasps, containing full 3D shape and pose sequences of 10 subjects interacting with 51 everyday objects of varying shape and size. Given MoCap markers, we fit the full 3D body shape and pose, including the articulated face and hands, as well as the 3D object pose. This gives detailed 3D meshes over time, from which we compute contact between the body and object. This is a unique dataset, that goes well beyond existing ones for modeling and understanding how humans grasp and manipulate objects, how their full body is involved, and how interaction varies with the task. We illustrate the practical value of GRAB with an example application; we train GrabNet, a conditional generative network, to predict 3D hand grasps for unseen 3D object shapes. The dataset and code are available for research purposes at https://grab.is.tue.mpg.de.Comment: ECCV 202
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