Non-bilayer formation in the DPPE-DPPG vesicle system induced by deep rough mutant of Salmonella minnesota R595 lipopolysaccharide

The vesicle system consisting of 80 mol% dipalmitoylphosphatidylethanolamine (DPPE) and 20 mol% dipalmitoylphosphatidylglycerol (DPPG) undergoes to structural changes caused by various concentrations of Salmonella minnesota R595 lipopolysaccharide (LPS). The phenomenon was investigated by methods applying small- and wide-angle X-ray scattering (SAXS and WAXS), calorimetry (DSC) and freeze-fracture. In the low LPS concentration regime (investigated at 0.02 LPS/DPPE–DPPG molar ratio) a phase separation was observed. Two kind of domains are formed which are rich and poor in DPPE and in these domains cubic and lamellar structures are present, respectively. Increasing the LPS concentration up to 0.1 LPS/DPPE–DPPG molar ratio the phase separation is more expressed and the temperature domains of the phase transitions are more different. Increasing the temperature chain melting of the lamellar phase occurs first and destruction of the cubic phase is observed later. At high LPS concentration (equimolar ratio of LPS/DPPE–DPPG), where this amphiphilic molecule cannot be considered any more a guest molecule, the cubic structure dominates the phase behaviour of the LPS molecules.     

Cobalt(II) complexes with disubstituted 3-aminopyrazole derivative: Mononuclear Co(II) complex with in situ prepared formamidine ligand

In the reaction of Co(NO₃)₂ · 6H₂O with 4-acetyl-3-amino-5-methylpyrazole (aamp) two octahedral Co(II) complexes, [Co(aamp)₂(H₂O)₄](NO₃)₂, 1, and [Co(ampf)(MeOH)₂NO₃]NO₃ (ampf = N,N′-bis(4-acetyl-5-methylpyrazole-3-yl)formamidine), 2, were obtained, depending on the reaction conditions. The presence of water in the reaction system leads to incorporation of water molecules into the crystal lattice and 1 was formed. In an anhydrous environment, due to addition of CH(OEt)₃, the fusion of two aamp was induced through their NH₂-groups, incorporating the methine group of CH(OEt)₃. As a result, complex 2, containing an adenino-mimetic NNO pharmacophore ligand, was obtained. The crystal and molecular structure of both compounds was determined. The coordination of aamp in 1 was achieved through N2 of the pyrazole ring. On the contrary, in 2, an unusual coordination mode of pyrazole is found: one of the pyrazole moieties, due to steric hindrance, coordinates through the oxygen atom of the acetyl group instead of N2. The complexes were characterized by elemental analysis and electronic spectra. For 2 a comprehensive IR spectral analysis is given. The metal-ligand interactions in 2 are analyzed by quantum chemical computations. The desolvation mechanism of both compounds is discussed in detail.     

First-principles prediction and partial characterization of the vibrational states of water up to dissociation

A new, accurate, global, mass-independent, first-principles potential energy surface (PES) is presented for the ground electronic state of the water molecule. The PES is based on 2200 energy points computed at the all-electron aug-cc-pCV6Z IC-MRCI(8,2) level of electronic structure theory and includes the relativistic one-electron mass-velocity and Darwin corrections. For H₂¹⁶O, the PES has a dissociation energy of D₀ = 41 109 cm⁻¹ and supports 1150 vibrational energy levels up to 41 083 cm⁻¹. The deviation between the computed and the experimentally measured energy levels is below 15 cm⁻¹ for all the states with energies less than 39 000 cm⁻¹. Characterization of approximate vibrational quantum numbers is performed using several techniques: energy decomposition, wave function plots, normal mode distribution, expectation values of the squares of internal coordinates, and perturbing the bending part of the PES. Vibrational normal mode labels, though often not physically meaningful, have been assigned to all the states below 26 500 cm⁻¹ and to many more above it, including some highly excited stretching states all the way to dissociation. Issues to do with calculating vibrational band intensities for the higher-lying states are discussed.     

Aeroacoustics research in Europe: The CEAS-ASC report on 2010 highlights

The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on an European scale and European aeronautics activities internationally. In this context, “aeroacoustics” encompasses all aerospace acoustics and related areas. Each year the committee highlights some of the research and development projects in Europe.This paper is a report on highlights of aeroacoustics research in Europe in 2010, compiled from information provided to the ASC of the CEAS.At the end of 2010, project X-NOISE EV of the Seventh Framework Programme of the European Commission has been launched as a continuation of the X-Noise series, with objectives of reducing aircraft noise and reaching the goal set by the ACARE 2020 Vision.Some contributions submitted to the editor summarizes selected findings from European projects launched before or concluded in 2010, while other articles cover issues supported by national associations or by industries. Furthermore, a concise summary of the workshop on “Aeroacoustics of High-Speed Aircraft Propellers and Open Rotors” held in Warsaw in October is included in this report.Enquiries concerning all contributions should be addressed to the authors who are given at the end of each subsection.     

Microwave-assisted selective protection of glutaraldehyde and its symmetrical derivatives as monoacetals and -thioacetals

Six monoprotected acetals and -thioacetals of glutaradehyde and its symmetrical dimethyl derivatives were synthesized. Microwave-assisted heating proved to be a substantially more selective method for monoprotection than conventional heating. All reactions were efficient and only traces of diprotected material were formed.     

Bond pricing under a Markovian regime-switching jump-augmented Vasicek model via stochastic flows

In this article, we shall explore the state of art of stochastic flows to derive an exponential affine form of the bond price when the short rate process is governed by a Markovian regime-switching jump-diffusion version of the Vasicek model. We provide the flexibility that the market parameters, including the mean-reversion level, the volatility rate and the intensity of the jump component switch over time according to a continuous-time, finite-state Markov chain. The states of the chain may be interpreted as different states of an economy or different stages of a business cycle. We shall provide a representation for the exponential affine form of the bond price in terms of fundamental matrix solutions of linear matrix differential equations.     

Hexane dehydrogenation to hexenes: a general indicator for deactivation of Pt catalysts in “skeletal” reactions

The comparative evaluation of dehydrogenation yields and selectivities of skeletal reactions from n-hexane reactions on monofunctional Pt catalysts is a good universal indicator of catalyst deactivation, independently of the presence and the nature of the support. Four regions could be defined with increasing carbon accumulation, causing "beneficial", "selective", "nonselective" and "severe" deactivation.     

Noise-enhanced human balance control

Noise can enhance the detection and transmission of weak signals in certain nonlinear systems, via a mechanism known as stochastic resonance. Here we show that input noise can be used to improve motor control in humans. Specifically, we show that the postural sway of both young and elderly individuals during quiet standing can be significantly reduced by applying subsensory mechanical noise to the feet. We further demonstrate with input noise a trend towards the reduction of postural sway in elderly subjects to the level of young subjects. These results suggest that noise-based devices, such as randomly vibrating shoe inserts, may enable people to overcome functional difficulties due to age-related sensory loss.