2,054 research outputs found

    Electronic structure of YbB6_{6}: Is it a Topological Insulator or not?

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    To resolve the controversial issue of the topological nature of the electronic structure of YbB6_{6}, we have made a combined study using density functional theory (DFT) and angle resolved photoemission spectroscopy (ARPES). Accurate determination of the low energy band topology in DFT requires the use of modified Becke-Johnson exchange potential incorporating the spin-orbit coupling and the on-site Coulomb interaction UU of Yb 4f4f electrons as large as 7 eV. We have double-checked the DFT result with the more precise GW band calculation. ARPES is done with the non-polar (110) surface termination to avoid band bending and quantum well confinement that have confused ARPES spectra taken on the polar (001) surface termination. Thereby we show definitively that YbB6_{6} has a topologically trivial B 2pp-Yb 5dd semiconductor band gap, and hence is a non-Kondo non-topological insulator (TI). In agreement with theory, ARPES shows pure divalency for Yb and a pp-dd band gap of 0.3 eV, which clearly rules out both of the previous scenarios of ff-dd band inversion Kondo TI and pp-dd band inversion non-Kondo TI. We have also examined the pressure-dependent electronic structure of YbB6_{6}, and found that the high pressure phase is not a Kondo TI but a \emph{p}-\emph{d} overlap semimetal.Comment: The main text is 6 pages with 4 figures, and the supplementary information contains 6 figures. 11 pages, 10 figures in total To be appeared in Phys. Rev. Lett. (Online publication is around March 16 if no delays.

    A standardized formula for aesthetic mandibular reconstruction using an osteocutaneous fibular free flap

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    Ameloblastoma is the most common benign odontogenic tumor of the jaw, and expansional growth of a huge untreated ameloblastoma can result in disturbances in facial aesthetics and function, such as difficulty with mouth opening, swallowing, chewing, breathing, neurologic deficits, and pathologic fractures. Radical wide resection with safety margins and subsequent reconstruction is generally recommended. A fibular free flap (FFF) is commonlyused to reconstruct the mandible in order to adequately restore both aesthetic appearance and function. The aim of this brief clinical report is to present a case of huge ameloblastoma after wide resection with free safety margins, and describe the immediate one-step mandibular reconstruction using a vascularized composite FFF. The sterolithographic(rapid prototype, RP) model, a wax pattern of the resected mandible, and a surgical fibular stent made from the wax pattern were constructed preoperatively. We suggest a standardized surgical protocol for mandibular reconstruction with FFF.Funding: Supported by the International Research & Development Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2015K1A3A9A01028230)Keywords: Mandibular reconstruction, fibular osteocutaneous free flap, huge ameloblastoma, stereolithographicmodel, standardized formul

    Recombinant Influenza Virus Carrying the Conserved Domain of Respiratory Syncytial Virus (RSV) G Protein Confers Protection Against RSV Without Inflammatory Disease

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    Respiratory syncytial virus (RSV) is one of the most important causes for viral lower respiratory tract disease in humans. There is no licensed RSV vaccine. Here, we generated recombinant influenza viruses (PR8/RSV. HA-G) carrying the chimeric constructs of hemagglutinin (HA) and central conserved-domains of the RSV G protein. PR8/RSV.HA-G virus showed lower pathogenicity without compromising immunogenicity in mice. Single intranasal inoculation of mice with PR8/RSV.HA-G induced IgG2a isotype dominant antibodies and RSV neutralizing activity. Mice with single intranasal inoculation of PR8/RSV.HA-G were protected against RSV infection as evidenced by significant reduction of lung viral loads to a detection limit upon RSV challenge. PR8/RSV.HA-G inoculation of mice did not induce pulmonary eosinophilia and inflammation upon RSV infection. These findings support a concept that recombinant influenza viruses carrying the RSV G conserved-domain can be developed as a promising RSV vaccine candidate without pulmonary disease

    Lead and Cadmium Levels and Balance and Vestibular Dysfunction among Adult Participants in the National Health and Nutrition Examination Survey (NHANES) 1999–2004

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    Background: Few studies have been conducted to identify risk factors for balance and vestibular dysfunction in general populations, but previous studies have reported evidence of adverse effects of lead and cadmium on balance control in high-risk groups

    Rapid exploration with multi-rotors: A frontier selection method for high speed flight

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    Exploring and mapping previously unknown environments while avoiding collisions with obstacles is a fundamental task for autonomous robots. In scenarios where this needs to be done rapidly, multi-rotors are a good choice for the task, as they can cover ground at potentially very high velocities. Flying at high velocities, however, implies the ability to rapidly plan trajectories and to react to new information quickly. In this paper, we propose an extension to classical frontier -based exploration that facilitates exploration at high speeds. The extension consists of a reactive mode in which the multi-rotor rapidly selects a goal frontier from its field of view. The goal frontier is selected in a way that minimizes the change in velocity necessary to reach it. While this approach can increase the total path length, it significantly reduces the exploration time, since the multi-rotor can fly at consistently higher speeds

    Effects of Synchronization of Carbohydrate and Protein Supply in Total Mixed Ration with Korean Rice Wine Residue on Ruminal Fermentation, Nitrogen Metabolism and Microbial Protein Synthesis in Holstein Steers

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    Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N) released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS). In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR) were determined. In Experiment 2, three total mixed ration (TMR) diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP) and neutral detergent fiber (NDF) but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS), 0.77 (MS) and 0.95 (HS), respectively. The diets were fed at a restricted level (2% of the animal’s body weight) in a 3×3 Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF) (p>0.05). The ruminal NH3-N content of the LS group at three hours after feeding was significantly higher (p0.05). In addition, the purine derivative (PD) excretion in urine and microbial-N production (MN) among the three groups were not significantly different (p>0.05). In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS) in Holstein steers
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