gaz-angubin is a sweet exudate naturally produced by an insect from the gavan-e-gaz-angubin plant. adsorption and desorption isotherms for a gaz-angubin sample were determined at 15° and 25°c over a range of relative humidity from 0 to 90% using a dynamic vapor sorption system. at different levels of relative humidity, changes in sample mass were continuously measured versus time and described ...

We investigated the structure and dynamics of water in contact with a monolayer of artificial lung surfactant (LS), composed of four types of lipids and one protein. The interfacial water is investigated with frequency-domain and time-domain surface sum-frequency generation spectroscopy, in which the vibrational relaxation of specifically interfacial water molecules can be followed. We compare ...

background: the purpose of this study was to investigate the enhanced thermal resistance mechanism of the du145 tumor spheroid cultures as compared to the prostate carcinoma cell line's monolayer cultures. materials and methods: du145 cells were cultured either as spheroids or monolayers. cultures were treated with hyperthermia in a precision water bath (at 43°c for 60 minutes) and/or quercetin...

Low-energy (100 eV) electron-stimulated reactions in layered H2O/CO/H2O ices are investigated. For CO layers buried in amorphous solid water (ASW) films at depths of 50 monolayers (ML) or less from the vacuum interface, both oxidation and reduction reactions are observed. However, for CO buried more deeply in ASW films, only the reduction of CO to methanol is observed. Experiments with layered ...

Heterodyne-detected (phase-sensitive) vibrational sum frequency generation spectroscopy was used to investigate molecular structures of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers on water (Langmuir monolayer) and monolayers on a fused silica substrate (Langmuir-Blodgett [LB] monolayer). The spectral features in the CH stretching region depended on the phase of the Langmuir mo...

In order to develop a versatile model for blood-compatible materials, we studied morphology and platelet adhesion of a dipalmitoyl-phosphatidylcholine (DPPC)/dipalmitoyl-phosphatidylethanolamine-polyethylene glycol (PEG lipid) mixed monolayer. This monolayer, which mimics the cell membrane structure, consists of two heterogeneous layers, that is, a PEG layer lying on top of a phospholipid monol...

A water droplet in contact with a platinum surface was simulated by the molecular dynamics method. Water molecules were modeled with the well-known SPC/E model and the platinum surface was represented by three layers of harmonic molecules. The phantom molecules were used beneath the layers of platinum surface in order to mimic the constant temperature heat bath. As the potential function betwee...

Competition and oxidation of fatty acids spread at the air/water interface were investigated using surface-specific, broad-bandwidth, sum frequency generation spectroscopy. At the air/water interface, a monolayer of oleic acid replaced a monolayer of deuterated palmitic acid at equilibrium spreading pressure. Subsequent oxidation of the oleic acid monolayer with ozone resulted in products more ...

We present results of molecular dynamics simulations of a model DPPC-water monolayer using charge equilibration (CHEQ) force fields, which explicitly account for electronic polarization in a classical treatment of intermolecular interactions. The surface pressure, determined as the difference between the monolayer and pure water surface tensions at 323 K, is predicted to be 22.92 ±1.29 dyne/cm,...

Insoluble monolayers on water have been patterned at the macroscopic scale (i.e., at the centimeter scale of the flow apparatus) as well as the mesoscopic scale (i.e., down to the micron scale resolvable via optical microscopy). The macroscopic patterning at the air/water interface results from a hydrodynamic instability leading to a steadily precessing flow pattern. The velocity field is measu...