Molecular systematics and ultrastructural characterization of a forgotten species: Chattonidium setense (Ciliophora,Heterotrichea)

In the present paper we redescribe the ciliate Chattonidium setense Villeneuve 1937 combining morphological observations (live, stained, scanning, and transmission electron microscope) with behavioral notes and molecular data. Ultrastructural analysis revealed remarkable similarities between Chattonidium and representative members of the class Heterotrichea in cortical structure and cytoplasmic organization. The most similar genus for these aspects appears to be Condylostoma. To verify this relatedness, 18S rRNA genes from Chattonidium and from one Condylostoma species were sequenced. Phylogenetic analysis indicates Chattonidium belongs to the class Heterotrichea defined according to the modern taxonomy, and confirms its relatedness with Condylostoma already hypothesized by Villeneuve-Brachon (1940). The presence of the aboral cavity complex, a unique feature never described in other ciliates, and its peculiar organization revealed by ultrastructural analysis fully justify, in our opinion, the maintenance of Chattonidium in the separate family Chattonidiidae, established by Villeneuve-Brachon in 1940.     

Fluorescent detection of glutamate with a dicopper(II) polyamine cage

A dicopper(II) octamine cage includes selectively the l-glutamate ion in water at pH 7, establishing Cu²⁺/-COO⁻ coordinative interactions. In particular, l-glutamate is able to displace the quenched rhodamine indicator from the cage, whose fluorescence is then fully restored. Other typical neurotransmitters (glycine, GABA) and some related amino acids are discriminated.     

Phonon spectra and structure of crystalline ethylene oxide and ethylene sulphide at 77 k

Vibrational spectra of solid ethylene oxide and ethylene sulphide were measured at 77 K. The analysis of the exciton splitting components was carried out using infrared polarized radiation. By comparing the amount of frequency separation in the IR and in the Raman spectra and the difference in the frequency values in these two spectra, an assignment is proposed which obeys the selection rules of a C_{2 h} centrosymmetric factor group for both molecules.     

A Radiation Condition for the 2-D Helmholtz Equation in Stratified Media

We study the 2-D Helmholtz equation in perturbed stratified media, allowing the existence of guided waves. Our assumptions on the perturbing and source terms are not too restrictive. We prove two results. Firstly, we introduce a Sommerfeld–Rellich radiation condition and prove the uniqueness of the solution for the studied equation. Then, by careful asymptotic estimates, we prove the existence of a bounded solution satisfying our radiation condition.     

On the 2D Cahn–Hilliard Equation with Inertial Term

Galenko et al. proposed a modified Cahn–Hilliard equation to model rapid spinodal decomposition in non-equilibrium phase separation processes. This equation contains an inertial term which causes the loss of any regularizing effect on the solutions. Here we consider an initial and boundary value problem for this equation in a two-dimensional bounded domain. We prove a number of results related to well-posedness and large time behavior of solutions. In particular, we analyze the existence of bounded absorbing sets in two different phase spaces and, correspondingly, we establish the existence of the global attractor. We also demonstrate the existence of an exponential attractor.