Heat capacities of transfer of some amino acids and peptides from water to aqueous urea solution

Integral enthalpies of solution at low concentrations of several amino acids and peptides in 2 and 6M urea solutions have been determined at 25 and 35°C. These data have been used to derive the enthalpies of transfer (at 25 and 35°C) and heat capacities of transfer (at 30°C) of these amino acids and peptides from water to aqueous urea solutions. Furthermore, the enthalpies of transfer and heat capacities of transfer per CH₂ group and per peptide group ? CONH? have also been estimated. These results show that while the enthalpies and heat capacities of transfer per CH₂ group are positive and negative, respectively, the reverse is true for ? CONH? group. The implications of these results in the mechanism of the denaturation of proteins by urea are discussed.     

Small Sample Comparison of Some Tests for Equality of Two Proportions

Powers of some tests of equality of two proportions are compared for small samples and approximate level .05. Numerical results indicate that the asymptotic results hold also for small and moderate sample sizes.     

Thermodynamics of some nucleic acid bases and nucleosides in water, and their transfer to aqueous glucose and sucrose solutions at 298.15 K

The partial molar heat capacities and volumes of some of the constituents of nucleic acids have been determined in water and 1 molal aqueous glucose and sucrose solutions in order to elucidate the nature of interactions occurring between various nucleic acid bases, nucleosides and the sugar (glucose and sucrose) molecules. The results have been explained in terms of the contributions from hydrophobic interactions, hydrophilic interactions and the hydrogen bonding between the solute and solvent molecules. The results have also been compared with those of amino acids and peptides in aqueous glucose and sucrose solutions.     

Neutroperiodism in different varieties of groundnut with respect to zinc and its uptake as affected by phosphorus application

Summary A greenhouse experiment was conducted to study the Zn uptake at various growth stages of groundnut plant. Soil used for the study was non calcareous typic Torripsamment, low in available Zn. Results obtained revealed that highest amount of Zn was accumulated in shoot portion at midflowering and declined severely at 75 days of plant growth. Its concentration in shoot portion increased again at maturity. Maximum Zn translocation from the shoot portion to fruits occurred between 50 and 75 days growth period. P application showed an antagonistic effect on Zn uptake. re]19760213     

A waveguide imaging platform for live‐cell TIRF imaging of neurons over large fields of view

Large fields of view (FOVs) in total internal reflection fluorescence microscopy (TIRFM) via waveguides have been shown to be highly beneficial for single molecule localisation microscopy on fixed cells [1,2] and have also been demonstrated for short‐term live‐imaging of robust cell types [3‐5], but not yet for delicate primary neurons nor over extended periods of time. Here, we present a waveguide‐based TIRFM set‐up for live‐cell imaging of demanding samples. Using the developed microscope, referred to as the ChipScope, we demonstrate successful culturing and imaging of fibroblasts, primary rat hippocampal neurons and axons of Xenopus retinal ganglion cells (RGCs). The high contrast and gentle illumination mode provided by TIRFM coupled with the exceptionally large excitation areas and superior illumination homogeneity offered by photonic waveguides have potential for a wide application span in neuroscience applications.