Proton exchange between spin groups of the solid matrix of hydrated granular potato starch and water was studied using the 2D time domain NMR. The proton spin–spin relaxation time T2, and spin–lattice relaxation time T1 (selective and non-selective pulse sequences) were measured at room temperature. The observed spin relaxation results were analysed for exchange assuming a two-site exchange mod...

Semiquantum liquid water molecular dynamics simulation was developed using the time-dependent Hartree approach. The classical intra- and intermolecular potential functions of water were extended to describe the wave packet (WP) hydrogen atoms. The equations of motion with an extended phase space including auxiliary coordinates and momenta representing the hydrogen WP widths were derived and sol...

In a recent paper in this journal, Chiu et al. (1995) presented a molecular dynamics study of a planar lipid bilayer membrane in water with the explicit incorporation of a surface tension. Parallel to the membrane plane, a negative pressure of-100 atmospheres was applied, derived from the measured surface tension of a monolayer at an air/water interface. The same approach was put forward by Fel...

This review describes recent advances in strategies for tuning the water-exchange rates of contrast agents for magnetic resonance imaging (MRI). Water-exchange rates play a critical role in determining the efficiency of contrast agents; consequently, optimization of water-exchange rates, among other parameters, is necessary to achieve high efficiencies. This need has resulted in extensive resea...

The importance of metabolic rate and/or spiracle modulation for saving respiratory water is contentious. One major explanation for gas exchange pattern variation in terrestrial insects is to effect a respiratory water loss (RWL) saving. To test this, we measured the rates of CO2 and H2O release ( and , respectively) in a previously unstudied, mesic cockroach, Aptera fusca, and compared gas exch...

Exchange of gases, such as O2, CO2, and CH4, over the air–water interface is an important component in aquatic ecosystem studies, but exchange rates are typically measured or estimated with substantial uncertainties. This diminishes the precision of common ecosystem assessments associated with gas exchanges such as primary production, respiration, and greenhouse gas emission. Here, we used the ...

Nanoscale zero-valent iron NZVI particles were synthesized by the aqueous phase borohydride reduction method, and the synthesized NZVI particles were used for the degradation of Basic Yellow 28 BY28 dye in aqueous solution. The influence of experimental variables such as reaction time, NZVI particle dosage and pH were studied on the decolorization of BY28. Mixing an aqueous solution of 100 mg L...

cation exchange capacity and specific surface area are among some of the important soil characteristics the direct measurement of which is laborious, costly and time consuming. therefore, fractal dimension of particle size distribution has been widely studied in relation with many such dynamic and static processes as transmission of water and solutes, water holding capacity, heat storage and co...