Environment effect

I.A. Abrikosov, A.M.N. Niklasson, S.I. Simak, B. Johansson, A.V. Ruban, and H.L. Skriver, Order-N Green s function technique for local environment effects in alloys, Phys. Rev. Lett. 76 4203 (1996). 

Iron in the feed concentrate is rejected either as unreacted pyrite mixed with elemental sulfur or as jarosites in the leach residue. The pyrite/sulfur mixtures said to be suitable for indefinite storage, but the well known environment effects caused by pyrite weathering are likely to make storage of this material a less than straightforward problem. Besides this, there are problems associated with the disposal of the leach residues from the pressure leach process. 

Sandrin, T. and Hoffman, D., Bioremediation of organic and metal co-contaminated environments Effects of metal toxicity, speciation, and bioavailability on biodegradation, in Environmental Bioremediation Technologies, Singh, S.N. and Tripathi, R.D., Eds, Springer, Berlin, Germany, 2007, pp. 1-34. 

In this contribution, we describe work from our group in the development and application of alternatives that allow the explicit inclusion of environment effects while treating the most relevant part of the system with full quantum mechanics. The first methodology, dubbed MD/QM, was used for the study of the electronic spectrum of prephenate dianion in solution [18] and later coupled to the Effective Fragment Potential (EFP) [19] to the study of the Claisen rearrangement reaction from chorismate to prephenate catalyzed by the chorismate mutase (CM) enzyme [20]. 

Another method that has been applied by our group to the study of enzymatic reactions is the Effective Fragment Potential (EFP) method [19]. The EFP method (developed at Mark Gordon s group at Iowa State University) allows the explicit inclusion of environment effects in quantum chemical calculations. The solvent, which may consist of discrete solvent molecules, protein fragments or other material, is treated explicitly using a model potential that incorporates electrostatics, polarization, and exchange repulsion effects. The solute, which can include some... 

The second approach described here for inclusion of environment effects is the use of hybrid quantum mechanics/molecular mechanics methods (QM/MM). In a QM/MM calculation [21,22], the system is partitioned in two regions A QM region, typically consisting of a relatively small number of atoms relevant for the specific process being studied, and a MM region with all the remaining atoms. 

Kay, K. (1970) Pesticides and associated health factors in agricultural environments effects on mixed-function oxiding enzyme metabolism, pulmonary surfactant and immunological reactions, in Pesticides Symposia, R. Dichmann (Ed.), Halos Co., Miami, FL. 

Environment, effect on changes in locomotor activity and brain 5-HT levels, 48-50 with LSD, 50-51... 

Environmental contamination usually consists of a mixture of pollutants and their partially degraded derivatives. Such an ill-defined chemical mixture will eventually lead to the formation of an ecosystem of microbes. The individual member species cannot survive in the toxic and hostile environment. Effective bioremediation technologies should therefore invoke a mixture of microorganisms forming synergistic consortia. Any realistic bioremediation concept is based on the recognition that it is the concerted action of various species, which may bring about the desired clean-up effect. 

In the mucosal environment, effects of salt, pH, temperature, and lipids need to be taken into consideration for possible effects on viscosity and solubility. A pH range of 4-7 and a relatively constant temperature of 37°C can generally be expected. Observed solution properties as a function of salt and polymer concentration can be referred to as saline compatibility. Polyelectrolyte solution behavior [27] is generally dominated by ionic interactions, such as with other materials of like charge (repulsive), opposite charge (attractive), solvent ionic character (dielectric), and dissolved ions (i.e., salt). In general, at a constant polymer concentration, an increase in the salt concentration decreases the viscosity, due to decreasing the hydrodynamic volume of the polymer at a critical salt concentration precipitation may occur. 

Hagberg, J.M., Wilund, K.R., Ferrell, R.E. (2000) APOE gene and gene-environment effects on plasma lipoprotein-lipid levels. Physiol. Genomics, 4, 101-108. 

As illustrated by the examples, the eatalytie properties of POMs may benefit from the assoeiation with the matrix, and in some eases both enhanced activity and selectivity have resulted from immobilization. That is often the ease of POMs embedding in silica matrix and may be attributed to a eonstrained environment effect . However, it is still very difficult to predict the catalytic performance after immobilization, and only experiment ean clarify this matter. Meanwhile, a rational modification of acid-base and/or hydrophobic-hydrophilic properties of a support is possible in some cases and may tune the catalytic properties. 

Islam, M. S., Rezwan, F. B., and Khan, S. I. (1996). Survival of Shigella flexneri in artificial aquatic environment Effects of different physicochemical stress factors. /. Diarrhoeal Dis. Res. 14,37-40. 

A.W. Davison, L.H. Weinstein, Some problems relating to fluorides in the environment Effects on plants and animals, in A. Tressaud (Ed.), Advances in Fluorine Science, Vol. 1, Elsevier, Amsterdam, 2006, pp. 251-298. 

Valuation. In the valuation step, all impacts are multiplied by norm factors. The resulting figures are added up to yield a single total figure. The norm factors are subjective, for they express the relative importance one gives to totally different environment effects. This subjectivity can be made more acceptable by having the norm factors set by a panel with representatives of various worldviews or political parties. 

C. Fonseca Guerra and F. M. Bickelhaupt, Angew. Chem., Ill, 3120 (1999) Angew. Chem. Snt. Ed., 38, 2942 (1999). Charge Transfer and Environment Effects Responsible for Characteristics of DNA Base Pairing. 

Vanmarcke, H., Janssens, A., Raes, F., Poffijn, A., Berkens, P. Van Dingenen, R. (1987) The behaviour of radon daughters in the domestic environment effect on the effective dose equivalent. In Radon and its Decay Products, ed. P.K. Hopke, Washington, D.C., American Chemical Society, pp. 301-23. 

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