Production of 13C labelled pea flour for use in human digestion and fermentation studies

Stable isotope breath tests offer a new approach to the study of digestion and fermentation of carbohydrates in man. In this study, 13C labelled peas were grown by pulsing 250 ml 13CO2 into a sealed growth chamber. A second pulse was added to a portion of the peas to increase the 13C enrichment. This generated pea flour with an enrichment of 2.36 at.% excess (range 2.09-2.71 n = 3) and 8.64 atom % excess (range 7.37-9.78 n = 3) respectively. This represented incorporation of an absolute yield of 3.8% of the 13CO2 into peas in the 'once-labelled' treatment and 7.5% in the 'twice-labelled' treatment. Ingestion of a mixture of the labelled pea flour (300 mg) by two volunteers generated measurable 13CO2 excretion for breath test analysis. The profile of breath 13CO2 enrichment increased to a maximum within three hours after consuming the pea flour followed by a decrease almost back to baseline by 13 hours. Breath 13CO2 appeared to rise again after this apparent nadir at 13 hours until the end of the sampling period. Mathematical analysis of the data suggested that two peaks best described the profile of breath 13CO2 up to 13 hours. A third peak was necessary to describe the late rise in breath 13CO2 enrichment. This use of 13C enriched pea flour may provide a useful non invasive method for measurement of digestion and fermentation in vivo.     

Metformin and glitazones: does similarity in biomolecular mechanism originate from tautomerism in these drugs?

This theoretical study attempts to find out similarity between metformin and glitazone class of antidiabetic drugs. It was found that some tautomeric forms of both metformin and thiazolidinedione ring of glitazones have similar molecular electrostatic potential (MESP) surface and may bind to a common complementary surface. Complexation and docking studies were also carried out in order to support this hypothesis. Copyright © 2007 John Wiley & Sons, Ltd.     

Dynamics and Morphology of Holes in Dewetting of Thin Films

The formation and growth of holes in apolar nonslipping Newtonian thin films subjected to long-range Lifshitz-van der Waals forces are investigated based directly on numerical solutions of the thin-film equation. The nonphysical divergences of the hydrodynamic model and of the van der Waals force at the three-phase contact line are removed by inclusion of the short-range Born repulsion. Three distinct regimes of the hole growth after its appearance are identified: (1) a short, unsteady phase in which the dynamic contact angle and velocity change rapidly, followed by (2) a long, quasi-steady phase with slow logarithmic changes, and finally (3) a hindered phase in which rims of the neighboring holes overlap and lead to formation of equilibrium drops. The cross section of the rim surrounding a growing hole is noncircular and asymmetric, with higher slopes near the contact line. A slight depression is created ahead of the moving rim, but the regions of the film away from the rim remain undisturbed. For very viscous (e.g., polymeric) liquids displaying small contact angles, a nonlinear regime of hole growth (radius ~ timeq, with the exponent q approximately 0.7-0.9) is obtained for realistic time scales. Copyright 1999 Academic Press.     

The effect of low intra-sublattice repulsion on phase diagram of YBa2Cu3O6+x : A Monte Carlo simulation study

We report the results of Monte Carlo simulation of the phase diagram and oxygen ordering in YBa₂Cu₃O_6+x for low intra-sublattice repulsion. At low temperatures, apart from tetragonal (T), orthorhombic (OI) and ‘double cell’ ortho II phases, there is evidence for two additional orthorhombic phases labelled here asOI andOIII. At high temperatures, there was no evidence for the decomposition of theOI phase into theT andOI phases. We find qualitative agreement with experimental observations and cluster-variation method results.     

Nonleptonic decay matrix elements in the variable pressure bag model

The consequences of the variable pressure bag model for the nonleptonic decays of hyperons and Ω⁻ are investigated. Though the order of magnitude and the relative sign for the various decay amplitudes are correctly reproduced, the overall results are small by a factor of 2 to 4, indicating that the theoretical predictions are strongly dependent on the model parameters.     

Three-level approximation for interacting Boson transition-temperature calculation

The normal-superfluid phase-transition temperature of a dilute Bose system whose particles interact via a two-body potential composed of a hard core followed by a weak attractive tail is studied using the three-level approximation. It is found that, for such a system, the three-level approximation does give results, for the transition temperature, approximately equal to the lambda-transition temperature of liquid ⁴He. The condensed state is composed of ε₀ = 0, ε₁ = E₀/N and ε₂, such that the states ε₀ and ε₁ lie below the cutoff momentum.     

Conduction electron spin resonance in acceptor-type graphite intercalation compounds

An initial survey of the conduction electron spin resonance is presented for a series of graphite compounds intercalated with acceptor molecules: stages 1–3 AsF₅, stages 2–5 HNO₃, and stage 2 Br₂ and ICl. The g-values and lineshapes were studied as functions of temperature and concentration. The results suggest metallic behavior but with very small density of states at the Fermi energy: N(E_F) ～10²⁰/cm³ eV. The temperature dependence of the linewidth is dominated by an order-disorder transition of the intercalant layers, implying that the conduction electrons are not entirely confined to the graphite portion of the crystal. The decrease in g-value anisotropy upon intercalation can be understood in terms of Elliott's theory.     

Radiation-spin interaction, Gilbert damping, and spin torque

Magnetization relaxation processes, which are represented by the Gilbert damping term and the spin torque term in the Landau-Lifshitz-Gilbert (LLG) equation, are described by the radiation-spin interaction (RSI), where the radiation field is produced by magnetization precessional motion itself. It is shown that the LLG equation including the Gilbert damping term and the spin torque term is derived from the spin Hamiltonian containing the RSI. The derivation of the LLG equation is given in a self-consistent method. It is also shown that, according to RSI, the magnitude of the magnetization vector deviates from the magnetization saturation with the order of O(alpha(2)), where alpha is the Gilbert damping parameter.     

Low temperature survival of slender naiad (Najas flexilis) seeds

The response to drying and storage at -20 degrees C or in liquid nitrogen was studied in seeds of the freshwater aquatic plant Najas flexilis. The seeds of this species show some desiccation sensitivity, although post-harvest storage in water at 16 degrees C resulted in improvements in desiccation tolerance. There was 63% germination of seeds dried to 9.5% moisture content (30% RH) following this maturation period. Optimum moisture contents for seeds stored at -20 degrees C for 3 months and in liquid nitrogen for 1 week were ~11% and ~15%, respectively.     

Enhanced instability in thin liquid films by improved compatibility

We investigated experimentally the morphological evolution of thin polydimethylsiloxane films sandwiched between a silicon wafer and different bounding liquids with interfacial tensions varying by 2 orders of magnitude. It is shown that increasing the compatibility between film and bounding liquid by adding a few surfactant molecules results in a faster instability of shorter characteristic wavelength. Inversely, based on the characteristic parameters describing the instability we determined extremely small interfacial tensions with a remarkable accuracy.