Tunneling Radiation of Vector Particles in Four and Five Dimensional Black Holes

Recent research shows that the WKB approximation and the Hamilton-Jacobi method has been succeed in studying the tunneling radiation of vector particles. In view of this, our main aim in this letter is to study the Proca equation and the vector particles tunneling radiation in the 4-dimensional and 5-dimensional black holes. And finally, the results here show that the temperature of vector particle is the same as Dirac particle’s and other particle’s.     

Enhanced β Crystalline Phase in Poly(vinylidene fluoride) via the Incorporation of Graphene Oxide Sheets assisted by Supercritical CO2 Treatment

Graphene oxide (GO) sheets were pre-modified with a typical piezoelectric polymer, poly(vinylidene fluoride) (PVDF), using a simple supercritical carbon dioxide (SC CO₂) method, and then the PVDF-decorated GO was added into a PVDF matrix by solution blending. Transmission electron microscopy (TEM) revealed that the decorating degree of PVDF on the surface of the GO increased significantly with increasing of SC CO₂ pressure and PVDF concentration. The mechanism of the polymer adsorption on the GO sheets through favorable interaction between the GO and PVDF chains was identified via Fourier transform infrared spectroscopy (FTIR). Further, the crystallization behavior of PVDF/GO composites was investigated by differential scanning calorimetry (DSC), FTIR and polarized optical microscopy (POM). Interestingly, the composite with PVDF-decorated GO as the filler showed higher β-phase content compared to the composite with pristine GO as the filler. The study showed that the supercritical fluid-induced epitaxial crystallization process has significant potential for fabricating functional GO-based nanocomposties containing piezoelectric or conducting materials.     

Budding dynamics of individual domains in multicomponent membranes simulated by N-varied dissipative particle dynamics

We study the budding dynamics of individual domains in flat, multicomponent membranes using dissipative particle dynamics (DPD) simulations with varied bead number N, in which addition and deletion of beads based on their density at the membrane boundary is introduced. The budding process of a tubular bud, accompanied by a dynamical transition reflected in the energy and morphology evolutions, is investigated. The simulations show that budding duration is shortened with increasing line tension and depends on the domain size quadratically. At low line tension, increasing bending modulus accelerates budding at first, but suppresses the process as it increases further. In addition, the controlling role of the surface tension in the budding process is also explored. Finally, we use the N-varied DPD to simulate the experimentally observed multicomponent tubular vesicles, and the three bud growth modes are confirmed.     

Molar mass dependent growth of poly(epsilon-caprolactone) crystals in Langmuir films

Poly(epsilon-caprolactone) (PCL) samples with number average molar masses (Mn) ranging from 3.5 to 36 kg.mol-1 exhibit molar mass dependent nucleation and growth of crystals, crystal morphologies, and melting properties at a temperature of 22.5 degrees C in Langmuir films at the air/water (A/W) interface. At surface area per monomer, A, greater than approximately 0.37 nm2.monomer-1, surface pressure, Pi, and surface elasticity exhibit molar mass independent behavior that is consistent with a semidilute PCL monolayer. In this regime, the scaling exponent indicates that the A/W interface is a good solvent for the liquid-expanded PCL monolayers. Pi-A isotherms show molar mass dependent behavior in the vicinity of the collapse transition, i.e., the supersaturated monolayer state, corresponding to the onset of the nucleation of crystals. Molar mass dependent morphological features for PCL crystals and their subsequent crystal melting are studied by in situ Brewster angle microscopy during hysteresis experiments. The competition between lower segmental mobility and a greater degree of undercooling with increasing molar mass produces a maximum average growth rate at intermediate molar mass. This behavior is analogous to spherulitic growth in bulk PCL melts. The plateau regions in the expansion isotherms represent the melting process, where the polymer chains continuously return to the monolayer state. The magnitude of Pi for the plateau during expansion decreases with increasing molar mass, indicating that the melting process is strongly molar mass dependent.     

Suppressing Alpha-Hemolysin as Potential Target to Screen of Flavonoids to Combat Bacterial Coinfection

The rapid emergence of bacterial coinfection caused by cytosolic bacteria has become a huge threat to public health worldwide. Past efforts have been devoted to discover the broad-spectrum antibiotics, while the emergence of antibiotic resistance encourages the development of antibacterial agents. In essence, bacterial virulence is a factor in antibiotic tolerance. However, the discovery and development of new antibacterial drugs and special antitoxin drugs is much more difficult in the antibiotic resistance era. Herein, we hypothesize that antitoxin hemolytic activity can serve as a screening principle to select antibacterial drugs to combat coinfection from natural products. Being the most abundant natural drug of plant origins, flavonoids were selected to assess the ability of antibacterial coinfections in this paper. Firstly, we note that four flavonoids, namely, baicalin, catechin, kaempferol, and quercetin, have previously exhibited antibacterial abilities. Then, we found that baicalin, kaempferol, and quercetin have better inhibitions of hemolytic activity of Hla than catechin. In addition, kaempferol and quercetin, have therapeutic effectivity for the coinfections of Staphylococcus aureus and Pseudomonas aeruginosa in vitro and in vivo. Finally, our results indicated that kaempferol and quercetin therapied the bacterial coinfection by inhibiting S. aureus α-hemolysin (Hla) and reduced the host inflammatory response. These results suggest that antitoxins may play a promising role as a potential target for screening flavonoids to combat bacterial coinfection.     

Single molecule force spectroscopy on poly(vinyl alcohol) by atomic force microscopy

The elastic properties of poly(vinyl alcohol) (PVA) were investigated on the nanoscale using the new technique of single molecule force spectroscopy by atomic force microscopy (AFM). It was found that the elastic properties of PVA molecules scale linearly with their contour lengths. This finding corroborates that the deformation of individual PVA chains is measured. The force spectra of PVA show a kink at around 200 pN and cannot be fitted by an extended Langevin function. The deviation of the elastic behavior of PVA from a freely jointed chain model may indicate the presence of a suprastructure of PVA in NaCl solution.     

Post‐Treatment of CH3NH3PbI3/PbI2 Composite Films with Methylamine to Realize High‐Performance Photoconductor Devices

Organometallic halide perovskites have attracted great research interest as light‐active materials for use in optoelectronics. Here, we report a high‐performance photoconductor based on a methylammonium lead iodide (MAPbI₃) film that was prepared from a methylamine‐treated MAPbI₃/PbI₂ perovskite film. An ultrahigh responsivity of 3.6 A W^?1 and detectivity of 5.4×10¹² Jones were obtained for the film under 0.5 mW cm^?2 white‐light illumination. In addition, under 420 nm light irradiation, the film exhibited its highest responsivity and detectivity of 30 A W^?1 and 2.4×10¹⁴ Jones, respectively. The excellent photo‐response performance results from the improved electronic quality and suppressed nonradiative recombination channels of the treated perovskite thin film.     

A Ratiometric Fluorescent Probe for Hypochlorite Based on a Deoximation Reaction

The first ratiometric fluorescent probe for hypochlorite has been developed through regulation of the electron‐withdrawing ability of the electron acceptor in an intramolecular charge‐transfer (ICT) system by a deoximation reaction (see figure; EWG=electron‐withdrawing group).

     

Effects of film structure on electrochromic properties of the multilayer films containing polyoxometalates

Multilayer films of tungstophosphate anion (P₂W₁₈) and poly(allylamine hydrochloride) (PAH) were fabricated on quartz and ITO substrates by layer-by-layer self-assembly method. These films were characterized by UV–vis spectroscopy, cyclic voltammetry (CV), chronoamperometric (CA), chronocoulometry (CC) and atomic force microscopy (AFM). The effects of film structure on multilayer electrochromic properties were investigated. The electrochromic responses of the composite films were related to the surface coverage of anion and multilayer thickness. It was found that higher concentration of polycation and anion, or adding salt to the polycation solution used for multilayer film preparation led to thicker and denser film structure which improved optical contrast and coloration efficiency whereas prolonged response time.