Quantum phase transition between a Luttinger liquid and a gas of cold molecules

We consider cold polar molecules confined in a helical optical lattice similar to those used in holographic microfabrication. An external electric field polarizes molecules along the axis of the helix. The large-distance intermolecular dipolar interaction is attractive but the short-scale interaction is repulsive due to geometric constraints and thus prevents collapse. The interaction strength depends on the electric field. We show that a zero-temperature second-order liquid-gas transition occurs at a critical field. It can be observed under experimentally accessible conditions.     

Compton scattering from deuterium and the polarizabilities of the neutron

A new program of Compton scattering on deuterium is under way at the tagged-photon facility at MAX-Lab in Lund, Sweden. We will measure differential cross sections between 60° and 150° over the photon energy range 60–115?MeV in 5?MeV steps, with the ultimate goal of obtaining new precision information on the electric and magnetic polarizabilities of the neutron.     

Tobramycin and Nebramine as Pseudo‐oligosaccharide Scaffolds for the Development of Antimicrobial Cationic Amphiphiles

Antimicrobial cationic amphiphiles derived from aminoglycoside pseudo‐oligosaccharide antibiotics interfere with the structure and function of bacterial membranes and offer a promising direction for the development of novel antibiotics. Herein, we report the design and synthesis of cationic amphiphiles derived from the pseudo‐trisaccharide aminoglycoside tobramycin and its pseudo‐disaccharide segment nebramine. Antimicrobial activity, membrane selectivity, mode of action, and structure–activity relationships were studied. Several cationic amphiphiles showed marked antimicrobial activity, and one amphiphilic nebramine derivative proved effective against all of the tested strains of bacteria; furthermore, against several of the tested strains, this compound was well over an order of magnitude more potent than the parent antibiotic tobramycin, the membrane‐targeting antimicrobial peptide mixture gramicidin D, and the cationic lipopeptide polymyxin B, which are in clinical use.     

On a Characterization Theorem on a -adic Solenoids

Doklady Mathematics - According to the Heyde theorem the Gaussian distribution on the real line is characterized by the symmetry of the conditional distribution of one linear form in independent...     

Stability of self-assembled monolayers on titanium and gold

Methyl- and hydroxyl-terminated phosphonic acid self-assembled monolayers (SAMs) were coated on Ti from aqueous solution. Dodecyl phosphate and dodecyltrichlorosilane SAMs were also coated on Ti using solution-phase deposition. The stability of SAMs on Ti was investigated in Tris-buffered saline (TBS) at 37 degrees C using X-ray photoelectron spectroscopy, contact angle goniometry, and atomic force microscopy. For comparison purposes, a hydroxyl-terminated thiol SAM was coated on Au, and its stability was also investigated under similar conditions. In TBS, a significant proportion of phosphonic acid or phosphate molecules were desorbed from the Ti surface within 1 day, while the trichlorosilane SAM on Ti or thiol SAM on Au was stable for up to 7 days under similar conditions. The stability of hydroxyl-terminated phosphonic acid SAM coated Ti and thiol SAM coated Au was investigated in ambient air and ultraviolet (UV) light. In ambient air, the phosphonic acid SAM on Ti was stable for up to 14 days, while the thiol SAM on Au was not stable for 1 day. Under UV-radiation exposure, the alkyl chains of the phosphonic acid SAM were decomposed, leaving only the phosphonate groups on the Ti surface after 12 h. Under similar conditions, decomposition of alkyl chains of the thiol SAM was observed on the Au surface accompanied by oxidation of thiolates.     

Ion-molecule reactions and thermal isomerization of tricyclo[4.3.0.0]nona-4,8-diene radical cations to tricyclo[4.2.1.0]nona-2,7-diene radical cations in a γ-irradiated frozen Freon matrix

A four-step mechanism of isomerization of tricyclo[4.3.0.0^3,7]nona-4,8-diene radical cations to tricyclo[4.2.1.0^4,9]nona-2,7-diene radical cations in γ-irradiated frozen Freon-113 (CFCl₂CF₂Cl) matrix was suggested on the basis of ESR data. The rearrangement was found to occur via distonic form of the radical cations with spin and charge separation. Furthermore, it was shown that the primary radical cations abstracts hydrogen atom from methylene group of the parent molecule, whereas distonic radical cations reacts via attachment to the C=C bond at 110–119 K.     

Radiation-induced transformations of isolated organic molecules in solid rare gas matrices

The radiation-chemical behaviour of isolated organic molecules in solid rare gas matrices was studied using a combination of ESR and IR spectroscopy. The total radiation-chemical yields of degradation of organic molecules in solid argon and xenon were estimated. The effect of electron scavengers on the radiolysis of organic molecules in solid rare gases reveals that the main primary process is positive hole transfer from matrix to guest molecule. ESR spectra of a number of radical cations (alkanes, ethers, arenes) were characterized in a low-disturbing environment. It was found that the electronic characteristics (IP, polarizability) of the matrix used had crucial effect on trapping and reactions of the isolated radical cations.     

Essentially subnormal operators

An operator is essentially subnormal if its image in the Calkin algebra is subnormal. We shall characterize the essentially subnormal operators as those operators with an essentially normal extension. In fact, it is shown that an essentially subnormal operator has an extension of the form ``normal plus compact'.

The essential normal spectrum is defined and is used to characterize the essential isometries. It is shown that every essentially subnormal operator may be decomposed as the direct sum of a subnormal operator and some irreducible essentially subnormal operators. An essential version of Putnam's Inequality is proven for these operators. Also, it is shown that essential normality is a similarity invariant within the class of essentially subnormal operators. The class of essentially hyponormal operators is also briefly discussed and several examples of essentially subnormal operators are given.