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

To resolve the controversial issue of the topological nature of the electronic structure of YbB$_{6}$, 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 $U$ of Yb $4f$ 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 YbB$_{6}$ has a topologically trivial B 2$p$-Yb 5$d$ 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 $p$-$d$ band gap of 0.3 eV, which clearly rules out both of the previous scenarios of $f$-$d$ band inversion Kondo TI and $p$-$d$ band inversion non-Kondo TI. We have also examined the pressure-dependent electronic structure of YbB$_{6}$, 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.

Psycho-oncology in Korea: Past, present and future

Background: Psycho-oncology in Korea was introduced among the circle of consultation-liaison psychiatrists, in the 1990s. For almost 25 years, the field has been developing at a steady pace as the psychosocial needs of patients with cancer continue to increase. In this study, we review the history of psycho-oncology in Korea, in a chronological order, within the domains of clinical practice, research activity, training, and public policy. Main body: Before the 1990s, patients with cancer with psychiatric comorbidities were usually taken care of by consultation-liaison psychiatrists in general hospitals. In 1993, psycho-oncology was first introduced by psychiatrists. Psychologists, nurses, and social workers have also been increasingly involved in providing psychosocial care for patients with cancer. Professionals from various disciplines began to communicate, and agreed to found the Korean Psycho-Oncology Study Group (KPOSG) in 2006, the first academic society in this field. In 2009, National Cancer Center published the Recommendations for Distress Management in Patients with Cancer, which are consensus-based guidelines for Korean patients. In 2014, the KPOSG was dissolved and absorbed into a new organization, the Korean Psycho-Oncology Society (KPOS). It functions as a center of development of psycho-oncology, publishing official journals, and hosting annual conferences. There are many challenges, including, low awareness of psycho-oncology, presence of undertreated psychiatric disorders in patients with cancer, shortage of well-trained psycho-oncologists, stigma, and suicide risk. It is important to improve the cancer care system to the extent that psycho-oncology is integrated with mainstream oncology. Considering the socio-cultural characteristics of Korean cancer care, a Korean model of distress management is being prepared by the KPOS. Conclusion: This article provides an overview of the development, current issues, and future challenges of psycho-oncology in Korea. Through its long journey to overcome the many barriers and stigmas of cancer and mental illnesses, psycho-oncology is now acknowledged as an essential part of integrated supportive care in cancer. Active research and international cooperation can gradually shape the Korean model of distress management.ope

Suppression of the charge density wave instability in R2O2Bi (R=La, Er) due to large spin-orbit coupling

To explore the origin of the suppression of the charge density wave (CDW) in Bi2- square sheet of R2O2Bi (R: rare-earth elements), we have investigated the band structures and phonon dispersions of La2O2Bi and Er2O2Bi. We have found that the large spin-orbit coupling of Bi atoms together with the chemical pressure effect reduces the Fermi surface nesting, which results in the suppression of the CDW instability in R2O2Bi. The pressure effect has been checked for a similar compound, Er2O2Sb, which shows a series of structural distortions in the Sb layer under volume contraction, from herringbone type, to 1D-ladder type, and to square sheet. Furthermore, we show that the observed local disorder in the Bi square sheet of La2O2Bi can be explained by the phonon softening anomaly, which is also expected to describe the anomalous resistivity upturn observed in La2O2Bi upon cooling.open1112Nsciescopu

Ultrafast giant magnetic cooling effect in ferromagnetic Co/Pt multilayers

The magnetic cooling effect originates from a large change in entropy by the forced magnetization alignment, which has long been considered to be utilized as an alternative environment-friendly cooling technology compared to conventional refrigeration. However, an ultimate timescale of the magnetic cooling effect has never been studied yet. Here, we report that a giant magnetic cooling (up to 200 K) phenomenon exists in the Co/Pt nanomultilayers on a femtosecond timescale during the photoinduced demagnetization and remagnetization, where the disordered spins are more rapidly aligned, and thus magnetically cooled, by the external magnetic field via the lattice-spin interaction in the multilayer system. These findings were obtained by the extensive analysis of time-resolved magneto-optical responses with systematic variation of laser fluence as well as external field strength and direction. Ultrafast giant magnetic cooling observed in the present study can enable a new avenue to the realization of ultrafast magnetic devices.111Ysciescopu

Association of Plasma Retinol-Binding Protein 4, Adiponectin, and High Molecular Weight Adiponectin with Insulin Resistance in Non-Diabetic Hypertensive Patients

∙The authors have no financial conflicts of interest. Purpose: The aim of this study was to determine whether retinol-binding protein 4 (RBP4), adiponectin and high molecular weight (HMW) adiponectin are associated with insulin resistance (IR) and metabolic parameters in non-diabetic hypertensive patients. Also, we sought to compare the predictive values of these adipocytokines for IR in non-diabetic hypertensive patients. Materials and Methods: Analyses of RBP4, adiponectin, and HMW adiponectin were performed on 308 non-diabetic hypertensives (148 males, age 58 ± 10 years, 189 non-metabolic syndrome and 119 metabolic syndrome). The homeostasis model assessment (HOMA) index for IR, lipid profiles, and anthropometric measure-ments were assessed. Results: There was no significant difference in RBP4 levels according to the presence of metabolic syndrome, although adiponectin and HMW adiponectin were significantly lower in metabolic syndrome. Correlation analysis of log RBP4 with IR and metabolic indices revealed that there was no significant correlation of RBP4 with wais

Analysis of recent climate change over the Arctic using ERA-Interim reanalysis data

This study investigates recent climate change over the Arctic and its link to the mid-latitudes using the ERA-Interim global atmospheric reanalysis data from the European Center for Medium-Range Weather Forecast (ECMWF). Since 1979, substantial surface warming, associated with the increase in anthropogenic greenhouse gases, has occurred over the Arctic. The greatest warming in winter has taken place offshore in the Kara-Barents Sea, and is associated with the increase in turbulent heat fluxes from the marginal ice zone. In contrast to the marked warming over the Arctic Ocean in winter, substantial cooling appears over Siberia and eastern Asia, linked to the reduction of Arctic sea ice during the freezing season (September–March). However, in summer, very little change is observed in surface air temperature over the Arctic because increased radiative heat melts the sea ice and the amount of turbulent heat gain from the ocean is relatively small. The heat stored in the upper ocean mixed layer in summer with the opening of the Arctic Ocean is released back to the atmosphere as turbulent heat fluxes during the autumn and through to the following spring. This warming of the Arctic and the reduced sea ice amplifies surface cooling over Siberia and eastern Asia in winter

Early Bile Duct Cancer Detected by Direct Peroral Cholangioscopy with Narrow-Band Imaging after Bile Duct Stone Removal

Cholangioscopy not only enables the direct visualization of the biliary tree, but also allows for forceps biopsy to diagnosis early cholangiocarcinoma. Recently, some reports have suggested the clinical usefulness of direct peroral cholangioscopy (POC) using an ultra-slim endoscope with a standard endoscopic unit by a single operator. Enhanced endoscopy, such as narrow band imaging (NBI), can be helpful for detecting early neoplasia in the gastrointestinal tract and is easily applicable during direct POC. A 63-year-old woman with acute cholangitis had persistent bile duct dilation on the left hepatic duct after common bile duct stone removal and clinical improvement. We performed direct POC with NBI using an ultra-slim upper endoscope to examine the strictured segment. NBI examination showed an irregular surface and polypoid structure with tumor vessels. Target biopsy under direct endoscopic visualization was performed, and adenocarcinoma was documented. The patient underwent an extended left hepatectomy, and the resected specimen showed early bile duct cancer confined to the ductal mucosa