A modular subgroup invariance in a four-dimensional string

A four-dimensional closed supersymmetric string theory is constructed from the left-moving Neveu-Schwarz bosonic string and the right-moving superstring. The gauge group [SU(2)]⁶ arises from an algebraic compactification involving a new affine Kac-Moody construction in terms of Neveu-Schwarz operators. The theory is Lorentz-invariant, tachyon-free and has four-point one-loop amplitudes invariant under a subgroup of the modular group.     

Phase behavior of carbon dioxide-aromatic hydrocarbon mixtures

Occhiogrosso, R.N., Igel, J.T. and McHugh, M.A., 1986. Phase behavior of carbon dioxide-aromatic hydrocarbon mixtures. Fluid Phase Equilibria, 26: 165–179.Vapor-liquid-equilibria experiments are conducted at 299.25, 305.65, 316.25, 338.35, 363.15, and 383.15 K and for pressures up to 175 bar for the CO₂-isopropyl benzene (cumene) system. Pressure-composition information is obtained. The resulting experimental data are modeled using the Peng-Robinson equation-of-state. Two temperature-independent model parameters, δ_ij, which accounts for molecular interactions between CO₂ and cumene, and η_ij, which accounts for the size difference between CO₂ and cumene, are used to obtain good agreement between calculated and experimental data.The results for the CO₂-cumene system are compared to the CO₂-toluene and CO₂-m-xylene systems which are available in the literature. The CO₂-toluene and CO₂-m-xylene systems can be modeled using the same δ_ij and η_ij values used for the CO₂-cumene system.     

Gauge covariant local formulation of bosonic strings

A free bosonic string field action is constructed that is local and invariant under the infinite set of gauge transformations corresponding to the conformal group of the two-dimensional world sheet. This allows for a straightforward gauge covariant method of second-quantizing string field theory. The method of extension to the interacting case is presented.     

Oxygen-supplied mesoporous carbon nanoparticles for enhanced photothermal/photodynamic synergetic therapy against antibiotic-resistant bacterial infections

Pandemic and epidemic spread of antibiotic-resistant bacterial infections would result in a huge number of fatalities globally. To combat antibiotic-resistant pathogens, new antimicrobial strategies should be explored and developed to confront bacteria without acquiring or increasing drug-resistance. Here, oxygen saturated perfluorohexane (PFH)-loaded mesoporous carbon nanoparticles (CIL@ICG/PFH@O₂) with photothermal therapy (PTT) and enhanced photodynamic therapy (PDT) utility are developed for antibacterial applications. Ionic liquid groups are grafted onto the surface of mesoporous carbon nanoparticles, followed by anion-exchange with the anionic photosensitizer indocyanine green (ICG) and loading oxygen saturated PFH to prepare CIL@ICG/PFH@O₂. These CIL@ICG/PFH@O₂ nanoparticles exhibit effective PTT and enhanced PDT properties simultaneously upon 808 nm light irradiation. In vitro assays demonstrate that CIL@ICG/PFH@O₂ shows a synergistic antibacterial action against antibiotic-resistant pathogens (methicillin-resistant Staphylococcus aureus and kanamycin-resistant Escherichia coli). Moreover, CIL@ICG/PFH@O₂ could effectively kill drug-resistant bacteria in vivo to relieve inflammation and eliminate methicillin-resistant Staphylococcus aureus-wound infection under NIR irradiation, and the released oxygen can increase collagen deposition, epithelial tissue formation and blood vessel formation to promote wound healing while enhancing the PDT effect. This study proposes a platform with enhanced PTT/PDT effects for effective, controlled, and precise treatment of topical drug-resistant bacterial infections.

We report oxygen saturated perfluorohexane (PFH)-loaded mesoporous carbon nanoparticles (CIL@ICG/PFH@O₂) with photothermal therapy (PTT) and enhanced photodynamic therapy (PDT) utility for antibacterial applications.     

Mott transition for picosecond all-optical nor gate in CdSe

Using picosecond time resolved spectroscopy, we study the extinction kinetics of the optical transmission of CdSe platelets induced by strong optical pumping. We investigate particularly the all-optical gate capabilities (resulting from the bandgap shrinkage due to the Mott transition) for laser beams the wavelength of which ranges from 676 to 678 nm. The electron-hole plasma density necessary to enable the optical switching is determined (ϱ ∼ 2 × 10¹⁷cm⁻³ at 20K). The switch-off time (i.e. the transparency recovery time) is also studied at different wavelengths by picosecond spectroscopy.     

Incommensurate CDW in Rb0.3MoO3: 87Rb NMR

The ⁸⁷Rb NMR measurement was carried out in a single-crystal Rb_0.3MoO₃. Below 180 K the NMR line well characterized the existence of incommensurate CDW. The absence of lock-in transition was confirmed from the temperature dependence of line shape. The CDW held the incommensurate phase even at 77 K, in spite of the nearly commensurate value of CDW wave vector observed in the neutron diffraction experiment. The CDW amplitude obtained from NMR was consistent with the BCS curve.     

Anomalous elastic behaviour of monoclinic potassium hydrogen carbonate,KHCO3, in the vicinity of the phase transition at 318 K

The elastic constants of monoclinic KHCO₃ have been determined from resonance frequencies of thick plates at ca. 15 MHz in the range between 250 and 370 K. A strong elastic anisotropy is present with a maximum of the longitudinal stiffness near the direction of the hydrogen bonds within the (HCO₃)^2-₂ dimers. The shear stiffness c₆₆ related to transversal waves propagating along the twofold axis [0 1 0]′ and [1 0 0]′ with displacement vectors nearly parallel to [1 0 0]′ and [0 1 0]′, respectively, shows a drastic softening approaching 318 K from below and from above, indicating a ferroelastic transition. All other elastic constants behave normally except in the close vicinity of the transition temperature where in some cases a small discontinuity is visible. The components of the thermal expansion tensor undergo a discontinuous change at the transition. The pressure derivative of the transition temperature is 2.3 K kbar^-1. A comparison with alkali cyanides and KH₂PO₄ reveals that the interactions driving the transition are rather originating from order-disorder processes of protons as in KH₂PO₄ than from an orientational molecular disorder as in alkali cyanides.     

Ambient pressure superconductivity at 4–5 K in β-(BEDT-TTF)2AuI2

Crystals of β-(BEDT-TTF)₂AuI₂, derived from the sulfur-based organic donor bis(ethylenedithio) tetrathiafulvalene [BEDT-TTF or “ET”] have been synthesized by electrocrystallization and studied by rf penetration depth measurements at ambient pressure and at temperatures down to 0.45 K. The crystals were found to be superconducting at ambient pressure with T_c = 3.93–4.98 K, which represent the highest values of T_c thus far observed at ambient pressure for an organic superconductor. Measurements of the upper critical field anisotropy are reported.