Electronic spectra of XeNe molecules in the range 77100-90100 cm-1 near Xe* (6p, 5d, 6p’, 7s, 7p, 6d) obtained by the (3 + 1) REMPI and (2 + 1) REMPI methods

The electronic spectra of XeNe molecules in the range of 77100-90100 cm^-1 are measured by the method of laser resonance multiphoton ionization in a supersonic jet. The photoionization spectra are obtained upon two- and three-photon excitations of molecules and their ionization by the next photon. In the range of 80300-90100 cm^-1 near Xe*(5d, 6p’, 6d, 7s, and 7p), the spectra are obtained for the first time. A whole number of vibrational systems are measured in this range. The majority of vibrational systems near Xe* (5d, 6d, 7p, and 7s) are located in the red range with respect to their dissociation limits. In the blue range with respect to the dissociation limits, continua corresponding to transitions of molecules from the ground state to repulsive potential curves of excited states are detected. For a number of excited states of XeNe molecules, the vibrational analysis is performed and molecular constants are estimated.     

Lattice points in bodies of revolution II

In [3] it was shown that when a three-dimensional smooth convex body has rotational symmetry around a coordinate axis one can find better bounds for the lattice point discrepancy than what is known for more general convex bodies. To accomplish this, however, it was necessary to assume a non-vanishing condition on the third derivative of the generatrix. In this article we drop this condition, showing that the aforementioned bound holds for a wider family of revolution bodies, which includes those with analytic boundary. A novelty in our approach is that, besides the usual analytic methods, it requires studying some Diophantine properties of the Taylor coefficients of the phase on the Fourier transform side.     

On Lipschitz behaviour of some generalized derivatives

The aim of the present paper is to compare various forms of stable properties of nonsmooth functions at some points. By stable property we mean the Lipschitz property of some generalized derivatives related only to the reference point. Namely we compare Lipschitz behaviour of lower Clarke derivative, lower Dini derivative and calmness of Clarke subdifferential. In this way, we continue our study of λ-stable functions.     

Rapid and scalable synthesis of chiral bromolactones as precursors to α-exo-methylene-γ-butyrolactone-containing sesquiterpene lactones

The sesquiterpene lactones cover a diverse and pharmacologically important diversity space. In particular, the electrophilic α-exo-methylene-γ-butyrolactone moiety that is preponderant in this natural product family has been shown to readily engage in covalent inhibition via conjugate addition of cysteine residues in target proteins. However, the synthetic accessibility of sesquiterpenes or related probes to investigate their mode of action remains laborious. Herein, we present a rapid and scalable route to chiral bromolactones as enabling precursors in the synthesis of sesquiterpene lactones.     

Langevin network model of myosin

Langevin mode theory and the coarse-grained elastic network model (ENM) for proteins are combined to yield the Langevin network model (LNM). Hydrodynamic radii of 6 A were assigned to each alpha-carbon on the basis of matching experimental translational and rotational diffusion constants of lysozyme, myoglobin, and hemoglobin with those calculated using a rigid body bead model with hydrodynamic interactions described by the Rotne-Prager tensor. LNM analysis of myosin II indicates that all ENM-like modes are overdamped at water viscosities. The low-frequency LNM modes in the pre-power stroke structure (PDB code: 1VOM) are substantially less mixed than the corresponding modes of the post-power stroke structure (1Q5G). Results from a four-bead model of the myosin "lever arm" indicate that coupling between modes increases as the array departs from linearity and are consistent with the results for 1VOM and 1Q5G. The decay times for all overdamped Langevin modes are shorter than the calculated rotational tumbling times found for lysozyme and myosin.     

Highly diastereoselective self-assembly of chiral tris(m-ureidobenzyl)amino capsules

The self-assembly of chiral tris(m-ureidobenzyl)amines to give dimeric capsules is a highly diastereoselective process in solution, while in the solid state, the formation of the corresponding capsules is not only diastereoselective but also regioselective.     

Behaviour of semipermeable membrane devices in neutral pesticide uptake from waters

The application of semipermeable membrane devices (SPMDs) has been evaluated as a passive sampler for the collection of multiresidue pesticides in continental waters. Seven chlorinated, five organophosphorus, six carbamate, nine pyrethroid and ten other pesticides were tested in order to estimate which compounds can be retained with these devices. The effect of water parameters, such as temperature, pH, ionic strength and organic matter content, were evaluated for their effect on the retention of the pesticides by the SPMDs. Studies of uptake from water were performed in a glass beaker containing 2 L distilled water spiked with 50 ng L⁻¹ of each pesticide investigated. A SPMD was put in the beaker, under turbulent conditions, and analysed after 2 days’ extraction. The contents of each SPMD were microwave-assisted-extracted twice with 30 mL hexane–acetone, to 90 °C for 10 min, and this was followed by a cleanup based on acetonitrile partitioning and solid-phase extraction. Gas chromatography with tandem mass spectrometry detection was employed for determination of pesticides, and provided low limits of detection from 0.5 to 7 ng per SPMD. Higher absorption rates were observed for pyrethroid, organophosphorus and chlorinated compounds than for carbamates. Pesticide uptake rates were independent of the water composition and decreased at low temperature. Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.     

Raman microspectroscopy of polymeric materials

Vibrational spectroscopy is an important tool to characterize polymeric materials. Confocal Raman Microspectroscopy allows to analyze micrometric areas and yields information about the chemical and physical parameters of polymers. The interpretation of the Raman spectra is usually related to the properties and processing. Thus, this non‐destructive technique is appropriated to investigate the skin/core morphology of injection‐molded semicrystalline polymers, blends, interface of composites, etc.     

Exact diagonalization of Hubbard clusters at finite temperatures

Finite temperature electronic and magnetic properties of small clusters are investigated in the framework of the Hubbard model by using exact diagonalization methods and by sampling the different cluster topologies exhaustively. Results are discussed for the specific heat C(T), magnetic susceptibility χ(T), local magnetic moments μ_i(T), average magnetic moments $\overline\mu_N(T)$ and spin-correlation functions γ_ij(T). Representative cluster sizes and band-fillings are considered showing antiferromagnetic-like (AF) and ferromagnetic-like (FM) behaviors. For half-band filling ν= N the susceptibility shows an AF high-temperature behavior of the form χ≈1/(T + T_N) from which the cluster `Néel’ temperature T<sub>N</sub> is derived. In contrast, for ν= N + 1 a FM high-temperature behavior of the form χ≈1/(T - T<sub>C</sub>) is found, where T<sub>C</sub> can be interpreted as the cluster `Curie’ temperature. In both cases one also observes peaks in C(T), either at T?T_N or T?T_C, which reflect the development of spin fluctuationsand the breakdown of the low-temperature short-range magnetic order. The dependence of T_N and T_C on cluster size N and interaction strength U/t is analyzed in terms of effective Heisenberg spin interactions. Finally, the effects of temperature-induced structural fluctuations are discussed.