Checkerboard charge density wave and pseudogap in high-TcT_{c} cuprates

We consider the scenario where a 4-lattice constant, rotationally symmetric charge density wave (CDW) is present in the underdoped cuprates. We prove a theorem that puts strong constraint on the possible form factor of such a CDW. We demonstrate, within mean-field theory, that a particular form factor within the allowed class describes the angle-resolved photoemission and scan tunneling spectroscopy well. We conjecture that the ``large pseudogap'' in cuprates is the consequence of this type of charge density wave.Comment: We add a new section II on the symmetry property of the checkerboard CD

Antibody dependent enhancement infection of Enterovirus 71 in vitro and in vivo

BACKGROUND: Human enterovirus 71 (EV71) has emerged as a significant cause of acute encephalitis and deaths in young children. The clinical manifestations caused by EV71 varied from mild hand, foot and mouth disease to severe neurological complications and deaths, but its pathogenesis remains elusive. Antibody dependent enhancement (ADE) infection has been reported in various viruses and has been shown to contribute to disease severity. RESULTS: In this study, the presence of sub-neutralizing antibody was demonstrated to enhance EV71 infection in THP-1 cells and increase the mortality of EV71 infection in a suckling mouse model. Further, a secondary infection model was established to characterize the correlation between ADE and disease severity, and primary asymptomatic EV71 infection was shown to increase the mortality of the secondary EV71 infection in suckling mice. CONCLUSIONS: Together, these in vitro and in vivo experiments strongly supported the hypothesis of ADE infection of EV71. The present findings indicate ADE might contribute to the pathogenesis of severe EV71 infection, and raise practical issues of vaccine development and antibody-based therapy

Superconducting fluctuations and charge-4ee plaquette state at strong coupling

Recent experiments indicate that superconducting fluctuations also play an important role in overdoped cuprates. Here we apply the static auxiliary field Monte Carlo approach to study phase correlations of the pairing fields in a microscopic model with spin-singlet pairing interaction. We find that the short- and long-range phase correlations are well captured by the phase mutual information, which allows us to construct a theoretical phase diagram containing the uniform $d$-wave superconducting region, the phase fluctuating region, the local pairing region, and the disordered region. We show that the gradual development of phase coherence has a number of consequences on spectroscopic measurements, such as the development of the Fermi arc and the anisotropy in the angle-resolved spectra, scattering rate, entropy, specific heat, and quasiparticle dispersion, in good agreement with experimental observations. For strong coupling, our Monte Carlo simulation reveals an unexpected charge-4$e$ plaquette state with $d$-wave bonds, which competes with the uniform $d$-wave superconductivity and exhibits a U-shaped density of states

catena-Poly[[bis­(nitrato-κ2 O,O′)copper(II)]-μ-2,2′-(ethane-1,2-diyldithio)di-1,3,4-thia­diazole-κ2 N 4:N 4′]

In the title compound, [Cu(NO3)2(C6H6N4S4)]n, the CuII atom, occupying a crystallographic inversion centre, is six-coordinated by two N atoms of two 2,2′-[1,2-ethane­diyl­bis­(thio)]bis­[1,3,4-thia­diazole] ligands in trans positions, and four O atoms from two symmetry-related opposite nitrate anions, which are asymmetrically bonded, resulting in a strong distorted octa­hedral geometry of the central atom. The ethane group is equally disordered over two sites via another inversion centre. The bridging bidentate 2,2′-[1,2-ethanediylbis(thio)]bis­[1,3,4-thia­diazole] ligands link the CuII centres into a one-dimensional chain. The chains are inter­connected via inter­molecular S⋯O inter­actions [3.044 (4) and 3.084 (5) Å] and weak C—H⋯O hydrogen bonds, generating a three-dimensional supra­molecular structure