Unifying principles

At first glance, the contents of Chap. 9 read like a catchall for unrelated topics. In it we examine the intrinsic viscosity of polymer solutions, the diffusion coefficient, the sedimentation coefficient, sedimentation equilibrium, and gel permeation chromatography. While all of these techniques can be related in one way or another to the molecular weight of the polymer, the more fundamental unifying principle which connects these topics is their common dependence on the spatial extension of the molecules. The radius of gyration is the parameter of interest in this context, and the intrinsic viscosity in particular can be interpreted to give a value for this important quantity. The experimental techniques discussed in Chap. 9 have been used extensively in the study of biopolymers. 

CHEMISTR Y—An Experimental Science presents chemistry as it is today. It does so with emphasis upon the most enjoyable part of chemistry experimentation. Unifying principles are developed, as is appropriate in a modern chemistry course, with the laboratory work providing the basis for this development. When we are familiar with these widely applicable principles we no longer have need for endless memorization of innumerable chemical facts. To see these principles grow out of observations you have made... 

The title, CHEMISTRY—An Experimental Science, states the theme of this one year course. A clear and valid picture of the steps by which scientists proceed is carefully presented and repeatedly used. Observations and measurements lead to the development of unifying principles... 

The literature on interpolation, quadrature, and allied topics is abundant, but the general remainder theorem here developed provides both a unifying principle, and a technique to apply in making a selection from among a variety of possible formulas of approximation. 

However a new chemical discovery arises, an essential component of science is to explain that discovery on the basis of general principles. When a new general principle is posed, it is termed a hypothesis. A hypothesis is tentative until it can be confirmed in two ways. First, additional observations must be consistent with the hypothesis second, the hypothesis must predict new results that can be confirmed by experiments. If a hypothesis meets these tests, it is promoted to the status of a theory. A theory is a unifying principle that explains a collection of facts. 

Lyklema, J. (1987), "Electrical Double Layers on Oxides Disparate Observations and Unifying Principles", Chemistry and Industry, 741 -747. 

Science progresses by accumulating disparate evidence and uncovering the underlying unifying principles. The unity inherent in hydrolytic reactions is but one aspect of the simplicity of the principles by which Nature operates. 

Generation of a Disintegrating Force or Pressure as a Unifying Principle... 

Lyklema, J. (1987) Electrical double layers on oxides disparate observations and unifying principles. Chemistry Industry, 741-747... 

It is often said that Antoine Laurent Lavoisier did for chemistry what Isaac Newton did for physics and Charles Darwin for biology. He transformed it from a collection of disparate facts into a science with unified principles. 

Measurement uncertainty is increasingly gaining attention, in particular in the framework of accreditation. The new accreditation standard ISO/IEC 17025 [17], which has been in force from December 2002 on, contains clear requirements on the estimation of MU and when and how it should be stated in test reports. ISO/IEC 17025 requires MU to be reported when required by the client and when relevant to the application and interpretation of the measurement results in the framework of certain specifications or decision limits. The MU should be readily available and reported together with the result as X U, where U is the expanded uncertainty [17, 47, 51, 54]. Also Eurachem and CCMAS within the Codex Alimentarius deal with MU as a separate issue [14,18-20]. Some even claim that MU will become the main unifying principle of analytical data quality [37]. 

From Metal Complexes to Organometallic Compounds to Organic Compounds. Although bridging subdisciplines within chemistry is not often easy, the ubiquity of electron transfer apparently allows one possible unifying principle. Juilliard and Chanon, for example, have shown in an extensive review the obvious connections between photoactivated electron transfers in... 

It could be more correct to form peri-heterocyclic nomenclature in accordance with the unified principle based on the names of the corresponding peri-cyclic hydrocarbons for example, 1-azaacenaphthylene instead of benzo[cc/]indole and 1-oxaphenalene instead of naphtho[bc]py-rane. However, we tried to use as a rule the adopted names. Moreover, for... 

The search for relationships among the dynamic and equilibrium properties of related series of compounds has been a paradigm of chemists for many years. The discovery of such unifying principles and predictive relationships has practical benefits. Numerous relationships exist among the structural characteristics, physicochemical properties, and/or biological qualities of classes of related compounds. Perhaps the best-known attribute relationships are the correlations between reaction rate constants and equilibrium constants for related reactions commonly known as linear tree-energy relationships (LFERs). The LFER concept led to the broader concepts of QSARs, which seek to predict the environmental fate of related compounds based on correlations between their bioactivity or physicochemical properties and structural features. For example, therapeutic response, environmental fate, and toxicity of organic compounds have been correlated with... 

Aromaticity is one of the great unifying principles of chemistry and although it was devised for benzene and other hydrocarbons it was soon extended to heterocycles. For instance, the Hiickel rule was published in 1931 [1, 2], while Robinson introduced the aromatic sextet concept in 1925 [3-5] and extended it to five-membered heterocycles, considering that a C-C double bond can be replaced by an heteroatom bearing a lone pair [3-5] (see however [6]). In this review we will discuss only heteroaromaticity, leaving aside most aspects concerning aromaticity. Even so, the number of literature references is enormous so we will restrict ourselves to our own contributions and to some recent and important papers by others. 

Fyhrie, D.P.and Carter, D. R. (1986) A unifying principle relating stress to trabecular bone morphology. Journal of Orthopedic Research 4 304-317... 

That is, the particular function of the three concentrations defined by Q (reaction quotient) is always the same at equilibrium. This is true even though any individual concentration may vary by as much as a magnitude of 10. This unifying principle allows the calculation of conditions at equilibrium under virtually any set of conditions. 

Darveau CA, Suarez RK, Andrews RD, Hochachka PW (2002). Allometric cascade as a unifying principle of body mass effeds on metabolism. Nature 417 166-170... 

The influence of these heteroatoms on the reactivity of carbon-scaffolded molecules is briefly reviewed in Section 2.4.1. As one unifying principle, hydrogen-heteroatom bonds break and re-form dynamically in water. In contrast, carbon-heteroatom bonds are rarely broken at standard temperatures unless another bond is formed at the same time. In general, for a chemical reaction to proceed under standard conditions at a rate meta-bolically useful for terran organisms, new bonds must be formed as old bonds are broken, or soon thereafter. 

The reactivity of hydroxide ion (and that of other oxyanions) is interpreted in terms of two unifying principles (a) the redox potential of the YO /YO- (Y = H, R, HO, RO, and O) couple (in a specific reaction) is controlled by the solvation energy of the YO anion and the bond energy of the R-OY product (RX - - YO R-OY - - X ), and (b) the nucleophilic displacement and addition reactions of YO occur via an inner-sphere single-electron shift. The electron is the ultimate base and one-electron reductant which, upon introduction into a solvent, is transiently solvated before it is leveled (reacts) to give the conjugate base (anion reductant) of the solvent. Thus, in water the hydrated electron... 

A key issue that future studies on MS channels will continue to address is the question on unifying principles that could account for the mechanosensitivity of both prokaryotic and eukaryotic MS channels. As discussed in this article, the bilayer principle seems to apply to several channels from evolutionary diverse origins. Additional questions to address will be on the structural determinants critical for MS channel mechanosensitivity and on the nature of interactions between the channels and the membrane lipids. Finally, possible applications of these findings in nanotechnology and medicine will be central to the applied research that will result from the basic research on this fascinating class of membrane proteins. 

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