pH-Dependent Complexation and Polyelectrolyte Chain Conformation of Polyzwitterion-Polycation Coacervates in Salted Water

The phase behavior and chain conformational structure of biphasic polyzwitterion-polyelectrolyte coacervates in salted aqueous solution are investigated with a model weak cationic polyelectrolyte, poly(2-vinylpyridine) (P2VP), whose charge fraction can be...

DNA Compaction and Charge Neutralization Regulated by Divalent Ions in very Low pH Solution

DNA conformation is strongly dependent on the valence of counterions in solution, and a valence of at least three is needed for DNA compaction. Recently, we directly demonstrated DNA compaction and its regulation, mediated by divalent cations, by lowering the pH of a solution. In the present study, we found that the critical electrophoretic mobility of DNA is promoted to around −1.0 × 10−4 cm2 V−1 s−1 to incur DNA compaction or condensation in a tri- and tetravalent counterions solution, corresponding to an about 89% neutralized charge fraction of DNA. This is also valid for DNA compaction by divalent counterions in a low pH solution. It is notable that the critical charge neutralization of DNA for compaction is only about 1% higher than the saturated charge fraction of DNA in a mild divalent ion solution. We also found that DNA compaction by divalent cations at low pH is weakened and even decondensed with an increasing concentration of counterions.

Case study. Contusion of heart as a cause of death when fired from not a short distance by fractional gunshot

The severity of fractional gunshot wound when fired from not a short distance depends on complex factors, including lesion localization (in this case the heart region - vitally important body that is sensitive to concussion (contusion), and the total kinetic energy of the elements of the charge (fraction). If shots from not a short distance fraction in terms of getting it in a sufficiently large number and proximity to vital organs sensitive to contusion (heart) may cause fatal lesions. The cause damage of heart in the form of contusion except varieties of blunt trauma may be fractional gunshot wound when fired from not a short distance.