Simulating the Lyotropic Phase Behavior of a Partially Self-Complementary DNA Tetramer.

DNA oligomers in solution have been found to develop liquid crystal phases via a hierarchical process that involves Watson-Crick base pairing, supramolecular assembly into columns of duplexes, and long-range ordering. The multiscale nature of this phenomenon makes it difficult to quantitatively describe and assess the importance of the various contributions, particularly for very short strands. We performed molecular dynamics simulations based on the coarse-grained oxDNA model, aiming to depict all of the assembly processes involved and the phase behavior of solutions of the DNA GCCG tetramers.

In Silico Ultrafast Nonlinear Spectroscopy Meets Experiments: The Case of Perylene Bisimide Dye.

Spectroscopy simulations are of paramount importance for the interpretation of experimental electronic spectra, the disentangling of overlapping spectral features, and the tracing of the microscopic origin of the observed signals. Linear and nonlinear simulations are based on the results drawn from electronic structure calculations that provide the necessary parameterization of the molecular systems probed by light. Here, we investigate the applicability of excited-state properties obtained from linear-response time-dependent density functional theory (TDDFT) in the description of nonlinear spectra by employing the pseudowavefunction approach and compare them with benchmarks from highly accurate RASSCF/RASPT2 calculations and with high temporal resolution experimental results.

Development of a New Measure for Assessing Mentalizing: The Multidimensional Mentalizing Questionnaire (MMQ).

This research consists of two studies which aimed to: (1) evaluate the psychometric properties of a new self-report measure for the assessment of mentalizing, the Multidimensional Mentalizing Questionnaire (MMQ); and (2) investigate the ability of the instrument to discriminate between community and clinical populations. A sample of 349 participants (19% male, 81% female; = 38.6, = 15.

Multidimensional Potential Energy Surfaces Resolved at the RASPT2 Level for Accurate Photoinduced Isomerization Dynamics of Azobenzene.

We have used state-of-the-art ab initio restricted active RASPT2 computations using a 16 orbitals, 18 electrons active space to produce an extended three-dimensional map of the potential energy surfaces (PESs) of the ground and first nπ* excited states of azobenzene along CNNC torsion and the two CNN bending angles, which are the most relevant coordinates for the trans-cis photoisomerization process. Through comparison with fully unconstrained optimizations performed at the same level of theory, we show that the three selected coordinates suffice to correctly describe the photoisomerization mechanism and the S-S crossing seam. We also provide a map of the nonadiabatic coupling between the two states in the region where they get closer in energy.

Exploring the capabilities of optical pump X-ray probe NEXAFS spectroscopy to track photo-induced dynamics mediated by conical intersections.

X-ray spectroscopy is gaining a growing interest in the scientific community, as it represents a versatile and powerful experimental toolbox for probing the dynamics of both core and valence electronic excitations, nuclear motions and material structure, with element and site specificity. Among the various X-ray based techniques, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, which investigates the energy and probability of resonant core-to-valence transitions, has started to be applied to organic molecules: a recent UV-pump X-ray probe time-resolved NEXAFS experiment [Wolf et al., Nat.

Order and dynamics inside H-PDLC nanodroplets: an ESR spin probe study.

We have performed a detailed study of the order and dynamics of the commercially available BL038 liquid crystal (LC) inside nanosized (50-300 nm) droplets of a reflection-mode holographic-polymer dispersed liquid crystal (H-PDLC) device where LC nanodroplet layers and polymer layers are alternately arranged, forming a diffraction grating. We have determined the configuration of the LC local director and derived a model of the nanodroplet organization inside the layers. To achieve this, we have taken advantage of the high sensitivity of the ESR spin probe technique to study a series of temperatures ranging from the nematic to the isotropic phase of the LC.

Expected and unexpected behavior of the orientational order and dynamics induced by azobenzene solutes in a nematic.

We have explored the changes in the phase stability, orientational order, and dynamics of the nematic 4-cyano-4'-n-pentylbiphenyl (5CB) doped with either the trans or the cis form of different p-azobenzene derivatives using the ESR spin-probe technique. In particular, we have studied the effects induced by each of the seven nonmesogenic 4-R-phenylazobenzenes (R = H, F, Br, CH3, CF3, On-Bu, Ot-Bu) at 1% and 7% mole fraction on the order parameter and on the shift of the nematic-isotropic transition temperature (TNI), as reported by a nitroxide spin probe, and we have tried to relate them to the solute shape and charge distribution. In all the cases the presence of the azo-derivative causes a depression of T(NI), more pronounced for the cis isomers.

Relaxation processes of the liquid crystal ME6N in the isotropic phase studied by Raman scattering experiments.

We have investigated the Raman profiles of the nu(C[Triple Bond]N) and nu(C=O) vibrational modes of the nematic liquid crystal ME6N (4-cyanophenyl-4(')-hexylbenzoate) in the isotropic phase at different temperatures and used them as probes of the dynamics and structural organization of this liquid. The vibrational time correlation functions of the nu(C[Triple Bond]N) mode, rather adequately interpreted within the assumption of exponential modulation function (the Kubo-Rothschild theory), indicate that the system experiences an intermediate dynamical regime that gets only slightly faster with increasing temperature. However, this theory fails in predicting the non-exponential behavior that the time correlation functions manifest in the long time range (t>3 ps).

Foliar application of selenite and selenate to potato (Solanum tuberosum): effect of a ligand agent on selenium content of tubers.

The effect of a foliar spray of selenium on potatoes was investigated for 2 years. Amounts of 0, 50, and 150 g of Se ha(-)(1) were applied both as sodium selenate and as sodium selenite in water, either pure or with the addition of 0.15% of soluble leonardite as a source of humic acids (pH 7).

O2-dependent lipid peroxidation does not affect the molecular order in hepatoma microsomes.

Microsomal membranes from rat liver and from the fast-growing Morris hepatoma 3942A have been peroxidized to different extents and the order parameter of the membranes measured by fluorescence depolarization of the probe 1,6-diphenyl-1,3,5-hexatriene. The data have been analysed by applying a mathematical approach that takes into account simultaneously static and dynamic fluorescence parameters. It appears that tumour membranes are more ordered than the control and their order parameter does not increase with greater exposure to the action of O2 radicals in contrast to liver membranes.

Lipid peroxidation and fluidity of plasma membranes from rat liver and Morris hepatoma 3924A.

Plasma membranes isolated from the fast-growing, maximal-deviation, Morris hepatoma 3924A exhibit remarkable changes in lipid composition, lipid peroxidation and to some extent in the physical state with respect to rat liver plasmalemmas. A correlation appears to exist between the lower phospholipid: protein ratio, higher cholesterol: phospholipid ratio, lower rate of lipid peroxidation and decrease in fluidity in tumor plasma membranes.

Lipid composition, physical state, and lipid peroxidation of tumor membranes.

Studies were carried out on microsomes isolated from the highly differentiated (slow-growing) Morris hepatoma 9618A, on microsomes and plasma membranes from the poorly differentiated (fast-growing) Morris hepatoma 3924A, and rat liver used as control. The lipid composition (phospholipid and cholesterol content, degree of fatty acid unsaturation) and peroxidation of such membranes has been correlated with the order and fluidity of the membrane bilayer. The results indicate that substrate availability is the rate-limiting step in microsomal and plasma membrane lipid peroxidation of hepatoma 3924A.