Physical, chemical, biological, and toxicity data from the study of urban stormwater and ephemeral streams, Maricopa County, Arizona, water years 1992-95

1996 ◽  
Author(s):  
K.D. Fossum ◽  
R.G. Davis
Keyword(s):  
Ephemeral Streams ◽  
Toxicity Data ◽  
Urban Stormwater ◽  
Maricopa County ◽  
Physical Chemical

Ranking of toxics release inventory chemicals using a level III fugacity model and toxicity

1999 ◽  
Vol 39 (10-11) ◽  
pp. 83-90 ◽  
Author(s):  
F. G. Edwards ◽  
E. Egemen ◽  
R. Brennan ◽  
N. Nirmalakhandan
Keyword(s):  
Environmental Impact ◽  
Chemical Properties ◽  
Toxic Release Inventory ◽  
Toxicity Data ◽  
Fugacity Model ◽  
Physical Chemical ◽  
Ranking Systems ◽  
Mass Release ◽  
Environmental Protection Policy ◽  
Chemical Releases

In an effort to lessen the environmental impact of chemicals discharged by industry, some countries rank chemicals according to mass released each year and then set environmental protection policy based upon this ranking. These rankings have driven industries and companies to change their process configurations and their chemical releases to reduce the release of higher ranking chemicals. But, chemicals that are higher ranked due to mass release may not be particularly toxic nor persistent in the environment; conversely, lower ranked chemicals may be substantially more toxic and persistent in the environment. The physical/chemical properties of forty five organic chemicals from the EPA's Toxic Release Inventory were used as inputs to a Level III fugacity model to estimate fate, transport, and steady state concentrations of chemicals in the environment. The resulting concentrations in the air and water, for each chemical, were determined using the fugacity model and were then compared with toxicity data, the ratio was used as an indication of the environmental impact of the release of each chemical. The chemicals were then ranked according to the degree of environmental impact and the results were compared to other ranking systems reported in the literature.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Seeking to uncover biology's chemical roots

2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross
Keyword(s):  
Environmental Changes ◽  
Biological Systems ◽  
Significant Development ◽  
The Road ◽  
Physical Chemical ◽  
Systems Chemistry ◽  
Biological World ◽  
Inanimate Matter ◽  
The Origin Of Life ◽  
Opening Up

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.

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