Sonic booms and diffusion wakes generated by a heavy quark in thermal gauge-string duality

We evaluate the Poynting vector generated by a heavy quark moving through a thermal state of N=4 gauge theory using the gauge-string duality. A significant diffusion wake is observed as well as a Mach cone. We discuss the ratio of the energy going into sound modes to the energy coming in from the wake.     

Some rules forS(-2k) dipole sums?

Stieltjes conditions and the ratio test provide necessary but not sufficient conditions onS(-2k) dipole sums. If the dipole sums are accurate the associated [n, n –1] Padé approximant provides a better representation of (), the frequency-dependent dipole polarizability, than a truncated series expression and, in addition, should bound () below. It is shown how constraints on the dipole sums effect the form of the [2,1] Padé approximant and an additional constraint is derived that ensures the analyticity of the approximant on 0 < ₁. There then follows a discussion of the reliability of available literature dipole sum values for small molecules containing H, C, N and O.     

Acid-catalyzed rearrangements of tricyclo[4.3.2]Propellane derivatives

The acid-catalyzed rearrangements of three model tricyclo[4.3.2] propellane derivatives have been explored. In each case the observed products are proposed to arise via a concerted 1,2-shift of the cyclobutane bond having an antiperiplanar alignment with the leaving group (i.e., stereoelectronic control).     

Multiphase thermoplastic hybrid for controlled release of antimicrobial essential oils in active packaging film

Active packaging, a new technology concept in the field of food packaging, has been introduced in recent years in order to provide quality and safety, as well as extend the shelf life of food products. Antimicrobial (AM) agents can be incorporated directly into the active packaging and migrate in a controlled manner to the headspace between the food and the package, inhibiting bacteria growth on the food surface. Naturally derived AM agent, such as essential oils (EOs), has received considerable attention for food preservation purposes, because of their effective AM activity against various bacteria and fungi. In the present study, AM active film systems based on polypropylene/polyamide blends, montmorillonite nanoclays, and thymol EO were produced to investigate the feasibility of controlling the release rate of thymol from food packaging systems. Selective localization of thymol in a specific phase in the system that derives from thermodynamic affinity was assumed to be useful in controlling its migration rate from the film to the headspace. EO retention in the film under two different time conditions was measured by spectroscopic analysis. The release rate of EO was determined using Gas chromatography technique and analyzed by diffusion model approach. Inhibition of bacterial growth was periodically tested for Listeria and Escherichia coli bacteria. This study confirms the thermodynamic affinity of polyamide phase with thymol that has a positive effect in retaining the EO. Results show controlled AM behavior of the active packaging films, based on various blend compositions. Copyright © 2016 John Wiley & Sons, Ltd.     

Improved methods for thermal rearrangement of alicyclic α-hydroxyimines to α-aminoketones: synthesis of ketamine analogues as antisepsis candidates

Ketamine is an analgesic/anesthetic drug, which, in combination with other drugs, has been used as anesthetic for over 40 years. Ketamine induces its analgesic activities by blocking the N-methyl-D-aspartate (NMDA) receptor in the central nervous system (CNS). We have reported that low doses of ketamine administrated to patients before incision significantly reduced post-operative inflammation as reflected by reduced interleukin-6 (IL-6) sera-levels. Our data demonstrated in a rat model of Gram-negative bacterial-sepsis that if we inject a low dose of ketamine following bacterial inoculation we reduce mortality from approximately 75% to 25%. Similar to what we have observed in operated patients, the levels of TNF-α and IL-6 in ketamine-treated rats were significantly lower than in septic animals not treated with ketamine. On the base of these results, we have designed and synthesized series of new analogues of ketamine applying a thermal rearrangement of alicyclic α-hydroxyimines to a-aminoketones in parallel arrays. One of the analogues (compound 6e) displayed high activity in down-regulating the levels of IL-6 and TNF-α in vivo as compared to ketamine.     

Axial heat conduction effects in the entrance region of circular ducts

This paper describes the transport of thermal energy within a small distance after an abrupt wall temperature change in a circular duct. In general, the axial conduction becomes significant when the Peclet number is small. The results indicate that the inclusion of axial conduction in the fluid substantially increases the wall heat flux at near the thermal inlet location. The exact series solution leads to a modified Graetz type problem. This exact solution is augmented by an asymptotic solution describing the wall heat flux near the thermal entrance location.     

Long wave theory of absorption and reflection in molecular crystals

The theory of long waves originally developed by Born and Huang for ionic crystals and then adapted for molecular crystals with one molecule per unit cell by Hall is extended to include molecular crystals with two molecules per unit cell. A study is made of the non-analytic behaviour of the energy bands as the wave vector tends to zero and it is found that the energies of the optically excited levels will be different from the values usually assumed. The dispersion relation is obtained and used to discuss metallic reflectivity. The finite lifetime of the excited states can also be included in the theory and this has the effect of changing the position of maximum absorption as well as reducing the reflectivity. A comparison is made between the long wave theory, the simple form of Davydov theory and experiment.