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The layered van der Waals antiferromagnet MnBi2Te4 has been predicted to combine the band ordering of archetypical topological insulators such as Bi2Te3 with the magnetism of Mn, making this material a viable candidate for the realization of various magnetic topological states. We have systematically investigated the surface electronic structure of MnBi2Te4(0001) single crystals by use of spin- and angle-resolved photoelectron spectroscopy experiments. In line with theoretical predictions, the results reveal a surface state in the bulk band gap and they provide evidence for the influence of exchange interaction and spin-orbit coupling on the surface electronic structure.

This paper presents the influence of electron elastic scattering models, electron thermalization models, and chemical parameters on Geant4-DNA simulations of liquid water radiolysis under mega-electron-volt electron irradiation. The radiochemical yields are simulated using a new Geant4-DNA example. In particular, the influence of the new elastic scattering model recently developed is presented as well as the influence of improved electron thermalization models. The influence of a new chemistry constructor using parameters of another Monte Carlo track structure code is also described. The results calculated using these different models are compared with each other and with experimental data. For sub-mega-electron-volt electron simulations, the combination of the "G4EmDNAPhysics_option2" physics constructor with the recently developed elastic scattering model, the Meesungnoen electron thermalization model, and the "G4EmDNAChemistry_option1" chemistry constructor is recommended. [ABSTRACT FROM AUTHOR]

This paper presents the calculation of new elastic scattering cross sections for the simulation of electron interactions in liquid water. The calculations are based on the "ELastic Scattering of Electrons and Positrons by neutral Atoms" code, which adopts a Dirac partial wave analysis. A Muffin-tin potential was used in order to account for the liquid-phase of water, and the optical parameters of the correlation-polarization and the inelastic absorption potentials were optimized against vapour-phase water data. The differential and total elastic scattering cross sections calculated in the present work show a global agreement with the experimental data. The impact of these elastic scattering cross sections on the transport of electrons in liquid water was evaluated by track-structure simulations of range, dose-point-kernel, microdosimetric spectra, and ionization clustering using the Geant4-DNA simulation toolkit. The results are compared against those obtained with the elastic scattering models already available in Geant4-DNA and are discussed. [ABSTRACT FROM AUTHOR]

The odd parity nature of 4f states characterized by strong spin–orbit coupling and electronic correlations has led to a search for novel topological phases among rare earth compounds, such as Kondo systems, heavy Fermions, and homogeneous mixed-valent materials. Our target system is thulium telluride thin films whose bandgap is expected to be tuned as a function of lattice parameter. We systematically investigate the growth conditions of TmxTey thin films on SrF2 (111) substrates by molecular beam epitaxy. The ratio between Te and Tm supply was precisely tuned, resulting in two different crystalline phases, which were confirmed by x-ray diffraction and x-ray photoemission spectroscopy. By investigating the crystalline quality as a function of the substrate temperature, the optimal growth conditions were identified for the desired Tm1Te1 phase. Additional low energy electron diffraction and reflective high energy electron diffraction measurements confirm the epitaxial growth of TmTe layers. X-ray reflectivity measurements demonstrate that homogeneous samples with sharp interfaces can be obtained for varied thicknesses. Our results provide a reliable guidance to prepare homogeneous high-quality TmTe thin films and thus serve as a basis for further electronic investigations. [ABSTRACT FROM AUTHOR]

In the response to the demand for electrical energy, much effort aimed to develop and commercialize high temperature superconducting (HTS) power equipments has been made around the world. In Korea, companies and universities are developing a power distribution and transmission class HTS transformer that is one of the 21st century superconducting frontier projects. The composite winding of transmission class HTS transformer is concentrically arranged primary winding (High)-Secondary winding (Low)-tertiary winding (High) from center. Primary winding is continuous disk type, Secondary winding is layer type and tertiary winding is Double pancake type. For the development of transmission HTS transformer with composite winding, the cryogenic insulation technology should be established. We have been analyzed insulation composition and investigated electrical characteristics such as breakdown of LN2, barrier, kapton films and surface flashover on Fiber Reinforced Plastic (FRP) in Liquid nitrogen (LN2). We are going to compare with measured each value and apply the value to most suitable insulating design of the HTS transformer. [ABSTRACT FROM AUTHOR]

We report the results of fluoroscopically guided wire/stylet manipulation combined with endoluminal electrocauterization in seven patients with obstructed Tenckhoff peritoneal dialysis catheters. In preparation for clinical application, electrocauterization was performed using a stone basket to recanalize surgically removed Tenckhoff catheters obstructed with omental fat ingrowing through the side holes. All ingrowing omental fat was removed easily by electrocauterization with the rotating movement of a stone basket. The technique was then applied in vivo in seven cases with ingrowing omental fat and malpositioned catheter; six (86%) were successfully recanalized. Among those six cases with initial success, four maintained good catheter function with durable patency (mean 261.3 days). No significant complication was noted. [ABSTRACT FROM AUTHOR]

The authors investigate the bonding environment of an oxygen-deficient HfO2/Si film grown by means of pulsed laser deposition, by analyzing the Hf L3-edge extended x-ray absorption fine structure. The local characteristics around the Hf atom, such as the bond length or the number of nearest neighbors, are found to depend on the oxygen supply during film growth. The chemical states of these samples are also probed in situ by x-ray/ultraviolet photoelectron spectroscopies. The core-level binding energy and the work function for each sample are found to be correlated with the mean Hf–O bond length, implying a close connection between the chemical environment and bond nature. [ABSTRACT FROM AUTHOR]

We introduce the automation of the range difference calculation deduced from particle-irradiation induced β(+)-activity distributions with the so-called most-likely-shift approach, and evaluate its reliability via the monitoring of algorithm- and patient-specific uncertainty factors. The calculation of the range deviation is based on the minimization of the absolute profile differences in the distal part of two activity depth profiles shifted against each other. Depending on the workflow of positron emission tomography (PET)-based range verification, the two profiles under evaluation can correspond to measured and simulated distributions, or only measured data from different treatment sessions. In comparison to previous work, the proposed approach includes an automated identification of the distal region of interest for each pair of PET depth profiles and under consideration of the planned dose distribution, resulting in the optimal shift distance. Moreover, it introduces an estimate of uncertainty associated to the identified shift, which is then used as weighting factor to 'red flag' problematic large range differences. Furthermore, additional patient-specific uncertainty factors are calculated using available computed tomography (CT) data to support the range analysis. The performance of the new method for in-vivo treatment verification in the clinical routine is investigated with in-room PET images for proton therapy as well as with offline PET images for proton and carbon ion therapy. The comparison between measured PET activity distributions and predictions obtained by Monte Carlo simulations or measurements from previous treatment fractions is performed. For this purpose, a total of 15 patient datasets were analyzed, which were acquired at Massachusetts General Hospital and Heidelberg Ion-Beam Therapy Center with in-room PET and offline PET/CT scanners, respectively. Calculated range differences between the compared activity distributions are reported in a 2D map in beam-eye-view. In comparison to previously proposed approaches, the new most-likely-shift method shows more robust results for assessing in-vivo the range from strongly varying PET distributions caused by differing patient geometry, ion beam species, beam delivery techniques, PET imaging concepts and counting statistics. The additional visualization of the uncertainties and the dedicated weighting strategy contribute to the understanding of the reliability of observed range differences and the complexity in the prediction of activity distributions. The proposed method promises to offer a feasible technique for clinical routine of PET-based range verification.

Background/aims: A number of studies have suggested a key role played by certain resident gut bacteria in the development of large bowel cancer. The aim of the present study was to test the effect of a novel symbiotic preparation, which has been recently shown to beneficially modify gut ecosystem and systemic immunity, on either preneoplastic and neoplastic changes in a colon carcinogenesis model., Methodology: Sprague-Dawley rats were fed a standard diet for 1 week and then were randomly assigned to three groups. The control diet was given to groups A and B, whereas in group C, the same diet plus 2 mL of a probiotic mixture was given throughout the experiment. Thirty rats (groups B, C) each received a weekly subcutaneous injection of azoxymethane at a dose of 15 mg/kg of body weight for 10 weeks. Group A served as a control group and received a subcutaneous injection of saline for 10 weeks. Forty-five rats were sacrificed at 3-week observation and 60 rats at 20-week observation for assessing metaphase index together with aberrant crypt foci and intestinal immune system markers from one hand and tumor occurrence from the other, respectively., Results: Group A showed a significantly increased metaphase index either in aberrant crypt foci or in "normal appearing" crypts when compared to group A (p < 0.01). Group B rats caused a significant decrease at both sites (p < 0.05). The numbers of lymphocytes derived from the mesenteric lymph nodes in group B rats were significantly decreased (p < 0.01) as compared to either control and to group C. The percentage of CD8 lymphocytes in group C was significantly higher than that in group B. Group C showed a significantly reduced ratio of aberrant crypt foci/colon and of aberrant crypt per colon and per each single focus (p < 0.05). A total of 18 (90%) group B and 10 (50%) group C rats had colon tumors, this difference was significant. The mean number of colon tumors per rat was 2.2 and 1.0 in group B and C, respectively., Conclusions: Effective probiotics treatment, through mechanisms still to be fully elucidated (decreased fecal pH, specific reduction of carcinogenetic bacterial enzymes, modulation of gut-associated and systemic immune system etc.) has the potential to exert significant antimutagenic properties against colon cancer.

Objectives: In HFRS, there is a varying degree of disseminated intravascular coagulation which was evident in the early phase of the illness. It is believed also that DIC would be the consequence, at least in part, of functional changes of endothelium resulting in kinin activation and clinical syndrome. This study investigated the role of adhesion molecule in the pathogenesis of Hantaan virus-related disease., Methods: The expression of ICAM-1 antigen on the cell membrane of human umbilical vein endothelial cells was assessed by immunohistochemistry, and ICAM-1 mRNA in the endothelial cells was assessed by in situ hybridization after Hantaan virus infection (2.6 x 10(4) PFU/mL) with the time course., Results: In immunohistochemistry, the number of ICAM-1 positive cells increased with time during the 12 or 24 hours after infection. 5 to 10% of HUVECs had been positive after 12-24 hours and the number of positive cells decreased abruptly after 24 hours. Hantaan antigen had been noticed after 12 hours focally on the HUVECs but continued to proliferate into day 7 post-infection when most of HUVECs were infected by Hantaan virus. In situ hybridization showed identical patterns of ICAM-1 mRNA expression after Hantaan virus infection., Conclusion: It implies that the Hantaan virus infection on HUVECs would express more ICAM-1 on their surface and implicated in the pathogenesis of early clinical syndrome of HFRS.

Background: Hepatitis C virus (HCV) is known to be a major cause of non-A, non-B hepatitis (NANBH) and is thought to be an important causative agent of serious liver disease. Recently the role of HCV in the development of various liver disease is suggested., Methods: Sera from 222 patients with various liver diseases had been kept frozen at -20 degrees C until the test. Anti-HCV was detected using the ABBOTT HCV EIA Test System (ABBOTT Co., America) following the manufacturer's instructions. The assay uses a recombinant HCV antigen (C 100-3) synthesized in yeast., Results: HCV antibodies (anti-HCV) were detected in 35 (31.5%) of 111 HBsAg-negative patients. The prevalence rate of anti-HCV was 61.9% (13 out of 21 patients) in chronic hepatitis, 29.1% (14 out of 48) in liver cirrhosis, 26.3% (5 out of 19) in hepatocellular carcinoma and 13% (3 out of 23) in acute hepatitis was far less (3 out of 111 patients, 2. 7%) than that of HBsAg-negative patients (p < 0.01). In this group, anti-HCV was detected in 2 (5.1%) out of 39 liver cirrhosis, 1 (1.9%) out of 52 chronic hepatitis, among them 47 were biopsy-proven chronic active hepatitis, and none of 20 hepatocellular carcinoma., Conclusions: These data suggest that, in Korea, 1) coinfection of HCV and HBV is infrequent, 2) HCV might be an important cause of HBsAg-negative chronic hepatitis, 3) HCV is seemed to be a less likely important factor associated with liver cirrhosis or hepatocellular carcinoma in HBsAg-negative patients, but further prospective study with a large population is necessary.