Water interaction with biological

Ruffle, S. V. Michalarias, I. Ei, ].-C. Ford, R. C. Inelastic Incoherent Neutron Scattering Studies of Water Interacting with Biological Macromolecules. /. Am. Chem. Soc. 2002, 124, 565-569. 

Inelastic incoherent neutron scattering studies of water interacting with biological macromolecules. 

Interaction with Biological Substrates 14.4.3.1 Water-Soluble Antioxidants... 

In natural waters, arsenic may exist as one or more dissolved species, whose chemistry would depend on the chemistry of the waters. Over time, arsenic species dissolved in water may (1) interact with biological organisms and possibly methylate or demethylate (Chapter 4), (2) undergo abiotic or biotic oxidation, reduction, or other reactions, (3) sorb onto solids, often through ion exchange, (4) precipitate, or (5) coprecipitate. This section discusses the dissolution of solid arsenic compounds in water, the chemistry of dissolved arsenic species in aqueous solutions, and how the chemistry of the dissolved species varies with water chemistry and, in particular, pH, redox conditions, and the presence of dissolved sulfides. Discussions also include introductions to sorption, ion exchange, precipitation, and coprecipitation, which have important applications with arsenic in natural environments (Chapters 3 and 6) and water treatment technologies (Chapter 7). 

The possibility of using the electron paramagnetic resonance properties of Gd3+ to probe its environment in and interactions with biological molecules has previously received little attention in the literature (40). However, the possibility exists that Gd2+ will be a sensitive EPR probe for characterizing macromolecular biological systems such as the Ca2+-ATPase. The EPR spectra of Gd3+, which has S = 7/2. in neutral water and in two different buffers are shown in Figure 13A. The linewidths were found to be independent of pH over the usable range of these buffers and independent of temperature between 4 and 30°C, The spectrum of Gd2+ in neutral water is centered around 3248 G, with a linewidth of 530 G. As shown, Gd3+ in Pipes buffer, but not in Tes buffer, yielded a spectrum similar to that of the aqueous Gd2+ solution. On this basis, all of our Gd3+ EPR and NMR studies... 

Grant, E.H. "Determination of Bound Water in Biological Materials." In Proc. Workshop Physical Bases of Electromagnetic Interactions with Biological Systems, University of Maryland, 1979, p. 113. 

In contrast to the advantageous nature of CDs for molecular inclusion, their surface makes it more difficult for the highly hydrophilic CD molecule to interact with lipophilic biological membranes. For this reason, natural CDs have been chemically modified to alter their water solubility, interaction with biological membranes, and drug release properties. 

The time was ripe to look more into the interaction between molecules, and this is the topic of the series of papers Study of the Structure of Molecular Complexes from a first paper [73] dealing with a water molecule interacting with a lithium ion, to the paper number 14 [74], all concerned with water-water, water interacting with positive and negative ions and water interacting with molecules of eventual biological interest. The one or two readers of this paper are referred to my publication list printed in the Int. J. Quantum Chem. in a 1992 volume, kindly dedicated to me [75]. 

Virtually any water-insoluble substance that satisfies the required characteristics discussed in Section 4.7.2.1 can serve as a solid support. However, no ideal matrix has been introduced yet. But an important factor is the rapid development of solid supports. If, at present, some carrier is neglected owing to some undesirable quality, it may be suitable after appropriate modification. It is almost impossible to find a matrix material which does not interact with biological active molecules by hydrogen bonding or ionic or hydrophobic interaction. Occasionally, these interactions fortuitously improve adsorption selectivity, but according to the opinion of Egly and... 

In order to understand the role of arsenic in the environment it is necessary to have some knowledge of the chemical forms of arsenic present in different environmental media as well as their concentrations, biotransformation and interaction with biologically important molecules. This necessitates the availability of reliable methods for the specia-tion and quantification of arsenic in air, soil, water, and biological media. 

Looking for functional group balance water solubility and absorption ionization issues effect on solubility and absorption Drug combinations acid-base interactions Drug interactions with biological target good fit or not ... 

For both metals, aquatic toxicity is dictated by the amount of metal present in a soluble or ionic form. This is the form of the metal that is bioavailable and capable of interacting with biological organisms. Water quality parameters that modify the bioavailability of zinc and lead in water, listed in order of importance, include pH, dissolved organic carbon and hardness. Current water quality criteria are often based upon the dissolved concentrations of the metal, after mathematical calculation of the effects of only a limited set of these parameters. In the United States, for example, water quality criteria are based upon dissolved concentrations using only hardness to normalize for bioavailability (10). Water quality criteria for lead and zinc are shown in Table VI. 

In previous papers(i-.3), we have reported that a specially prepared poly(vinyl alcohol) (PVA) film is very low in protein adsorption and platelet adhesion compared with conventional PVA and other polymers. When PVA is used for practical applications as non aqueous solutions, physical or chemical crosslinking or acetalization is introduced to PVA to make it insoluble in water. Acetalization with formaldehyde and physical crosslinking by heat treatment (annealing) are the most common among the insolubilization methods(. However, for the minimum protein adsorption and platelet adhesion, these physical and chemical modifications have to be avoided because significant interactions with biological components are observed for such PVA, similar to the conventional polymers. 

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