Protein stability and function relies on residues being in their appropriate ionization states at physiological pH. In situ residue pK(a)s also provides a sensitive measure of the local protein environment. Multiconformation continuum electrostatics (MCCE) combines continuum electrostatics and molecular mechanics force fields in Monte Carlo sampling to simultaneously calculate side chain ioniza...

time-dependent schrödinger equation for a 1-d model of hydrogen molecular ion h2+ in intenselaser field linearly polarized along the molecular axis is solved. ionization rates are calculated for differentinitial states. the evolution of electronic wavefunction at fixed inter-nuclear separations are simulated andanalyzed. the results obtained for the ground state of this 1-d model of h2+ show ap...

The enol of a-cyano-a-phenylacetic acid was observed as a short-lived transient species formed upon flash photolytic generation of phenylcyanoketene by a photo-Wolff reaction of a-cyano-a-diazoacetophenone followed by hydration of the ketene. Rates of ketonization of the enol were measured in dilute hydrochloric acid solutions and acetic acid, biphosphate ion, tris(hydroxymethyl)methylamine, an...

The central r81e of the adenosinephosphates in biochemical mechanisms depends upon their phospholylation and dephosphorylation reactions (l3). The equilibria of these reactions depend upon pH, and therefore information concerning the various ionization constants is of fundamental importance. With the aid of the various ionization constants it, is possible (a) to calculate the variation in the e...

We present an enlarged and homogeneous set of interstellar hydrogen and helium column densities obtained through continuum and ionization edges fitting of nearby hot white dwarfs observed with the Extreme Ultraviolet Explorer (EUVE). We compare the HI columns towards the targets and their locations relative to the soft X-ray cavity contours drawn by Snowden et al. (1998). We then use the inferr...

Rotationally resolved spectra for the HfO(+) cation have been recorded using the pulsed field ionization zero electron kinetic energy (PFI-ZEKE) technique. Resonant excitation of the F(0(+))<--X (1)Sigma(+) band system of HfO was used as an intermediate level providing molecule and rovibrational state selectivity in the ionization process. The ionization energy (IE) of HfO, derived from the PFI...

introduction computed tomography scans are a very important tool for diagnosis and assessment of response to treatment in the practice of medicine. ionizing radiation in medical imaging is undoubtedly one of the most powerful diagnostic tools in medicine. yet, as with all medical interventions, there are potential risks in addition to the clear potential benefits. materials and methods two refe...

Mass spectrometry (MS)-based techniques have enormous potential for kinetic studies on enzyme-catalyzed processes. In particular, the use of electrospray ionization (ESI) MS for steady-state measurements is well established. However, there are very few reports of MS-based studies in the pre-steady-state regime, because it is difficult to achieve the time resolution required for this type of exp...