Orbital-Dependent Polaron Formation in the Relativistic Mott Insulator Sr\u3csub\u3e2\u3c/sub\u3eIrO\u3csub\u3e4\u3c/sub\u3e

We use optical spectroscopy to investigate the electron-phonon interaction in Sr2IrO4, a well-known 5d transition metal oxide with spin-orbit entangled states. The temperature evolution in the optical spectra is well described by the Fröhlich polaron model, indicating a large electron-phonon interaction. We further find that electrons in different orbitals selectively couple with different phonon modes. While Jeff = 3/2 holes do not seem to couple with any phonons, Jeff = 1/2 and 3z2−r2 electrons mainly couple with in-plane and out-of-plane Ir-O bending modes, respectively. The symmetries of the orbitals and phonons are consistent with our observations

Hopf term and the effective Lagrangian for the Skyrmions in a two-dimensional electron gas at small g-factor

We study interacting electrons in two dimensions moving in the lowest Landau level under the condition that the Zeeman energy is much smaller than the Coulomb energy and the filling factor is one. In this case, Skyrmion quasiparticles play an important role. Here, we present a simple and transparent derivation of the corresponding effective Lagrangian. In its kinetic part, we find a non-zero Hopf term the prefactor of which we determine rigorously. In the Hamiltonian part, we calculate, by means of a gradient expansion, the Skyrmion-Skyrmion interaction completely up to fourth order in spatial derivatives.Comment: 4 pages, Late

Multiplex reverse transcription-PCR for rapid differential detection of porcine epidemic diarrhea virus, transmissible gastroenteritis virus, and porcine group A rotavirus

A novel multiplex reverse transcription polymerase chain reaction (multiplex RT-PCR) that can detect porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and porcine group A rotavirus (GAR) was developed. The 3 viruses (PEDV, TGEV, and porcine GAR) are major agents in viral enteric diseases of piglets. As the clinical signs of these diseases are similar, including watery diarrhea, differential detection is required for etiologic diagnosis. A mixture of 3 pairs of published primers was used for amplification of viral nucleic acids, yielding 3 different amplicons with sizes of 859 bp, 651 bp, and 309 bp for TGEV, PEDV, and porcine GAR, respectively. A total of 157 specimens (78 fecal and 79 intestinal samples) from piglets with acute gastroenteritis were collected in Korea between January 2004 and May 2005. They were tested for the presence of 3 viruses by multiplex RT-PCR. Coinfections with PEDV and porcine GAR were identified in 16 farms (43.2%). PEDV, porcine GAR, and TGEV infection were 26.3%, 13.2%, and 2.7% respectively. The relative sensitivity and specificity of multiplex RT-PCR were evaluated, with results suggesting that this assay is equal in quality to conventional single-agent RT-PCR assays (sensitivity:100%, 92.9%, 100% for TGEV, PEDV, GARs; specificity: 100% for all 3 viruses). This multiplex RT-PCR is a simple assay and may be a potentially useful for rapid, sensitive, and cost-effective etiological diagnostic tool for acute viral gastroenteritis in piglets.This work was supported by Korea Research Foundation Grants (KRF-2002-070-C00069) and the Brain Korea 21 Project of the Ministry of Education & Human Resources Development, Republic of Korea

Optical Spectroscopic Studies of the Metal-Insulator Transition Driven by All-In-All-Out Magnetic Ordering in 5d Pyrochlore Cd2Os2O7

We investigated the metal-insulator transition (MIT) driven by all-in-all-out (AIAO) antiferromagnetic ordering in the 5d pyrochlore Cd2Os2O7 using optical spectroscopy and first-principles calculations. We showed that the temperature evolution in the band-gap edge and free carrier density were consistent with rigid upward (downward) shifts of electron (hole) bands, similar to the case of Lifshitz transitions. The delicate relationship between the band gap and free carrier density provides experimental evidence for the presence of an AIAO metallic phase, a natural consequence of such MITs. The associated spectral weight change at high energy and first-principles calculations further support the origin of the MIT from the band shift near the Fermi level. Our data consistently support that the MIT induced by AIAO ordering in Cd2Os2O7 is not close to a Slater type but instead to a Lifshitz type.open

Cilostazol Prevents Tumor Necrosis Factor-␣-Induced Cell Death by Suppression of Phosphatase and Tensin Homolog Deleted from Chromosome 10 Phosphorylation and Activation of Akt/Cyclic AMP Response Element-Binding Protein Phosphorylation

ABSTRACT This study examines the signaling mechanism by which cilostazol prevents neuronal cell death. Cilostazol (ϳ0.1-100 M) prevented tumor necrosis factor-␣ (TNF-␣)-induced decrease in viability of SK-N-SH and HCN-1A cells, which was antagonized by 1 M iberiotoxin, a maxi-K channel blocker. TNF-␣ did not suppress the viability of the U87-MG cell, a phosphatase and tensin homolog deleted from chromosome 10 (PTEN)-null glioblastoma cell, but it did decrease viability of U87-MG cells transfected with expression vectors for the sense PTEN, and this decrease was also prevented by cilostazol. Cilostazol as well as 1,3-dihydro-1-[2-hydroxy-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS-1619) and (3S)-(ϩ)-(5-chloro-2-methoxyphenyl)-1,3-dihydro-3-fluoro-6-(trifluoromethyl)-2H-indole-2-one (BMS 204352), maxi-K channel openers, prevented increased DNA fragmentation evoked by TNF-␣, which were antagonizable by iberiotoxin. TNF-␣-induced increased PTEN phosphorylation and decreased Akt/ cyclic AMP response element-binding protein (CREB) phosphorylation were significantly prevented by cilostazol, those of which were antagonized by both iberiotoxin and paxilline, maxi-K channel blockers. The same results were evident in U87-MG cells transfected with expression vectors for sense PTEN. Cilostazol increases the K ϩ current in SK-N-SH cells by activating maxi-K channels without affecting the ATP-sensitive K ϩ channel. Thus, our results for the first time provide evidence that cilostazol prevents TNF-␣-induced cell death by suppression of PTEN phosphorylation and activation of Akt/CREB phosphorylation via mediation of the maxi-K channel opening. Recent research has shown that the phosphatase and tensin homolog deleted from chromosome 10 (PTEN) is implicated in the regulation of several cellular functions, including cell viability from apoptosi

Fractionalization patterns in strongly correlated electron systems: Spin-charge separation and beyond

We discuss possible patterns of electron fractionalization in strongly interacting electron systems. A popular possibility is one in which the charge of the electron has been liberated from its Fermi statistics. Such a fractionalized phase contains in it the seed of superconductivity. Another possibility occurs when the spin of the electron, rather than its charge, is liberated from its Fermi statistics. Such a phase contains in it the seed of magnetism, rather than superconductivity. We consider models in which both of these phases occur and study possible phase transitions between them. We describe other fractionalized phases, distinct from these, in which fractions of the electron themselves fractionalize, and discuss the topological characterization of such phases. These ideas are illustrated with specific models of p-wave superconductors, Kondo lattices, and coexistence between d-wave superconductivity and antiferromagnetism.Comment: 28 pages, 11 fig

Enhanced resistance to bacterial and fungal pathogens by overexpression of a human cathelicidin antimicrobial peptide (hCAP18/LL-37) in Chinese cabbage

The human cathelicidin antimicrobial protein hCAP18, which includes the C-terminal peptide LL-37, is a multifunctional protein. As a possible approach to enhancing the resistance to plant disease, a DNA fragment coding for hCAP18/LL-37 was fused at the C-terminal end of the leader sequence of endopolygalacturonase-inhibiting protein under the control of the cauliflower mosaic virus 35S promoter region. The construct was then introduced into Brassica rapa. LL-37 expression was confirmed in transgenic plants by reverse transcription-polymerase chain reaction and western blot analysis. Transgenic plants exhibited varying levels of resistance to bacterial and fungal pathogens. The average size of disease lesions in the transgenic plants was reduced to less than half of that in wild-type plants. Our results suggest that the antimicrobial LL-37 peptide is involved in wide-spectrum resistance to bacterial and fungal pathogen infection

Going it alone? North Korea’s adaptability as a small power in a changing world

This article uses small states scholarship to map North Korea’s evolution from a post-colonial small state to a system-influencing state due to its nuclear weapons programme. The framework allows for contributions to: (1) The DPRK literature which in some parts has suggested the future collapse of the state, (2) The small states literature that suggests they can only survive if they integrate larger political and/or economic units, (3) The mainstream IR literature and its dominant realist streak that considers great powers and their will as the main drivers in contemporary world politics