Additivity of nonsimultaneous masking for short Gaussian-shaped sinusoids

The additivity of nonsimultaneous masking was studied using Gaussian-shaped tone pulses (referred to as Gaussians) as masker and target stimuli. Combinations of up to four temporally separated Gaussian maskers with an equivalent rectangular bandwidth of 600 Hz and an equivalent rectangular duration of 1.7 ms were tested. Each masker was level-adjusted to produce approximately 8 dB of masking. Excess masking (exceeding linear additivity) was generally stronger than reported in the literature for longer maskers and comparable target levels. A model incorporating a compressive input/output function, followed by a linear summation stage, underestimated excess masking when using an input/output function derived from literature data for longer maskers and comparable target levels. The data could be predicted with a more compressive input/output function. Stronger compression may be explained by assuming that the Gaussian stimuli were too short to evoke the medial olivocochlear reflex (MOCR), whereas for longer maskers tested previously the MOCR caused reduced compression. Overall, the interpretation of the data suggests strong basilar membrane compression for very short stimuli.     

Dimers of N‐Heterocyclic Carbene Copper,Silver, and Gold Halides: Probing Metallophilic Interactions through Electron Density Based Concepts

Homobimetallic metallophilic interactions between copper, silver, and gold‐based [(NHC)MX]‐type complexes (NHC=N‐heterocyclic carbene, i.e, 1,3,4‐trimethyl‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ylidene; X=F, Cl, Br, I) were investigated by means of ab initio interaction energies, Ziegler–Rauk‐type energy‐decomposition analysis, the natural orbital for chemical valence (NOCV) framework, and the noncovalent interaction (NCI) index. It was found that the dimers of these complexes predominantly adopt a head‐to‐tail arrangement with typical M ??? M distance of 3.04–3.64 Å, in good agreement with the experimental X‐ray structure determined for [{(NHC)AuCl}₂], which has an Au ??? Au distance of 3.33 Å. The interaction energies between silver‐ and gold‐based monomers are calculated to be about ?25 kcal mol^?1, whereas that for the Cu congener is significantly lower (?19.7 kcal mol^?1). With the inclusion of thermal and solvent contributions, both of which are destabilizing, by about 15 and 8 kcal mol^?1, respectively, an equilibrium process is predicted for the formation of dimer complexes. Energy‐decomposition analysis revealed a dominant electrostatic contribution to the interaction energy, besides significantly stabilizing dispersion and orbital interactions. This electrostatic contribution is rationalized by NHC(δ⁺) ??? halogen(δ^?) interactions between monomers, as demonstrated by electrostatic potentials and derived charges. The dominant NOCV orbital indicates weakening of the π backdonation in the monomers on dimer formation, whereas the second most dominant NOCV represents an electron‐density deformation according to the formation of a very weak M ??? M bond. One of the characteristic signals found in the reduced density gradient versus electron density diagram corresponds to the noncovalent interactions between the metal centers of the monomers in the NCI plots, which is the manifestation of metallophilic interaction.     

The catalytic reduction of NO by H2 on Ru(0 0 0 1): Observation of NHads species

Adsorption of NO and the reaction between NO and H₂ were investigated on the Ru(0 0 0 1) surface by X-ray photoelectron spectroscopy (XPS). Surface composition was measured after NO adsorption and after the selective catalytic reduction of nitric oxide with hydrogen in steady-state conditions at 320 K and 390 K in a 30:1 mixture of H₂ and NO (total pressure = 10⁻⁴ mbar). After steady-state NO reduction, molecularly adsorbed NO in both the linear on-top and threefold coordinations, NH_ads and N_ads species were identified by XPS. The coverage of the NH_ads and N_ads species was higher after the reaction at 390 K than the corresponding values at 320 K. Strong destabilisation of N_ads by O_ads was detected. A possible reaction mechanism is discussed.     

On the intrinsic bulk photovoltaic effect: Performing the sum over intermediate states

By using a different approach as proposed recently, we perform an analytical summation of virtual transitions to all Bloch bands in terms of derivatives of Bloch functions. This alternative discussion about the existence of an intrinsic bulk photovoltaic effect confirms our previous results. We also would like to emphasize that the bulk photovoltaic effect may be used as a sensitive tool investigating the electronic structure of a solid.     

A parabolic-elliptic variational inequality

An existence and uniqueness result is proved for a variational inequality of evolution. The problem consists of a nonlinear parabolic/elliptic differential equation for which Dirichlet, Neuman and Signorini boundary conditions are posed. The existence is obtained using a regularization process, while uniqueness is based on L¹-contractiveness of the solution semigroup.     

Photoelectron Spectra of Azabenzenes and Azanaphthalenes: III. The orbital sequence in methyl- and trimethylsilyl-substituted pyridines

The ionization potentials of methyl-, t-butyl- and trimethylsilyl-substituted pyridines have been determined by high-resolution photoelectron spectroscopy. The results are discussed in terms of destabilizing inductive and stabilizing conjugative effects of the substituents, and have been parametrized on the basis of a HMO-type perturbation treatment. Our data are in accord with the idea that the topmost occupied orbital in pyridine is a ‘lone pair’ orbital.     

Photoexcitation and photoionization of atoms at arbitrary temperature and matter density

Bound-bound and bound-free oscillator strengths are calculated based on a self-consistent Hartree-Fock-Slater model of the atom. The effect of variable matter density is analyzed in detail for cold helium. Data are also presented for the Al¹³ and Cs⁵⁵ atoms at different temperatures and matter densities.     

Investigation of Euphrasia rostkoviana Hayne Using GC–MS and LC–MS

Gas and liquid chromatography coupled with mass spectrometry was applied to solve difficulties and reinvestigate the serious matrix problems affecting analysis of the active compounds in Euphrasia rostkoviana Hayne. The main groups of compounds were obtained by extracting the herb stepwise with n-hexane, chloroform, ethyl acetate and methanol. Polyamide column chromatography facilitated further separation. Phenolic/flavonoid- and terpenoid-type molecules were studied by GC–MS, HPLC and LC–MS–MS. The β-sitosterol content of the herb was determined by gas chromatography with flame ionisation detection (GC-FID). Caffeic acid, chlorogenic acid, coumaric acid and flavonoid glycosides of apigenin, luteolin, rhamnetine (hexoside), kaempferol (both hexoside and rutinoside) and quercetin (rutinoside) were identified in the fractions of the methanolic extract.     

Patterned surfaces segregate compliant microcapsules

For both biological cells and synthetic microcapsules, mechanical stiffness is a key parameter since it can reveal the presence of disease in the former case and the quality of the fabricated product in the latter case. To date, however, assessing the mechanical properties of such micron-scale particles in an efficient, cost-effective means remains a critical challenge. By developing a three-dimensional computational model of fluid-filled, elastic spheres rolling on substrates patterned with diagonal stripes, we demonstrate a useful method for separating cells or microcapsules by their compliance. In particular, we examine the fluid-driven motion of these capsules over a hard adhesive surface that contains soft stripes or a weakly adhesive surface that contains "sticky" stripes. As a result of their inherently different interactions with the heterogeneous substrate, particles with dissimilar stiffness are dispersed to distinct lateral locations on the surface. Since mechanically and chemically patterned surfaces can be readily fabricated through soft lithography and can easily be incorporated into microfluidic devices, our results point to a facile method for carrying out continuous "on the fly" separation processes.