Organic Matrix Concept

One of the major difficulties in the interpretation of ultrastructural patterns is the realisation that one is dealing with relic structures that are frozen in mineral matter. There is no way to be sure that the shape and composition of the mineral matrix and even the mineral itself has remained the same. They may be partly or entirely different from the state both had at the time of formation. Some intermediary products involved in the regulation no longer exist and we are only left with the final products. 

The amount of organic matter in skeletal material can be as low as 0.01 percent in some mollusc shells, and as high as 20 to 30 percent in vertebrate bones or teeth in a few isolated instances concentrations may go up to 90 percent. The origin, nature and function of mineralized tissues in calcification is only tentatively known. 

It is the objective of the following discussion to coordinate in a meaningful way the often conflicting results found in the literature on mineral deposition processes. 

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Towe, K, M. Invertebrate shell structure and organic matrix concept. Biomineralisation 4,... 

Rouelle himself had studied the presence of water in chemical compounds, especially in the neutral salts where the water of crystallization is a readily demonstrated example of water in a fixed, combined, and solid form. In 1744, he coined the phrase water of crystallization that distinguished its chemical role from its physical role as solvent. We can leave to Rouelle s creativity the explanation of how he must have soon recognized the parallel patterns among these elements, and organized his chemical thinking accordingly How earth became a part of this pattern is readily seen in the history of the matrix concept recounted in Chapter Four. The instrumental role of the matrix became the crucible of the experimentalist, and the earthy part became the chemical earth of Rouelle s scheme ... 

Eastoe, J. E. Chemical Aspects of the Matrix Concept in Calcified Tissue Organization. 

In almost all instances of biological mineralization fibrous proteins represent the bulk of the organic matrix. In the past, this phenomenon has been interpreted to mean that proteins such as collagen, keratin or elastin are the key elements in mineralization by providing nucleation sites and at the same time offering structure and space for oriented crystal growth. However, with the advance in the field of biomineralization this model came under severe attack. At present, there is no universal concept which could explain all the intriguing facets of phosphate deposition in cellular systems. 

This review addresses the class of organic-inorganic nanohybrid materials consisting of an organic matrix phase, which is a polymer, and an inorganic disperse phase, which is a nanoscaled ceramic material. Thus, general synthetic approaches for preparation of polymer-ceramic nanohybrid materials will be introduced and specific properties thereof will be highlighted. Additionally, various advanced and prospective applications of polymer-cerantic nanohybrids will be addressed and discussed within the context of the concept of multifunctionality. 

It is common to think of process control functions stacked one above another in a pyramid or hierarchic arrangement as with traditional business or military organization structures, particularly when computers are involved. Multivariable control structures, however, with their extensive lateral and diagonal crossovers, are flmctionally more like the modern matrix concept of management. From... 

One potential solution to these problems, suggested some 20 years ago by Chantrell and Popper (1), involves the use of inorganic or organo-metallic polymers as precursors to the desired ceramic material. The concept (2) centers on the use of a tractable (soluble, meltable or malleable) inorganic precursor polymer that can be shaped at low temperature (as one shapes organic polymers) into a coating, a fiber or as a matrix (binder) for a ceramic powder. Once the final shape is obtained, the precursor polymer can be pyrolytically transformed into the desired ceramic material. With careful control of the pyrolysis conditions, the final piece will have the appropriate physical and/or electronic properties. 

This dilemma could be overcome by the hypercycle model hypercycles are in fact not theoretical concepts, but can be observed (in a simple form) in today s organisms, where an RNA virus transfers the information for an enzyme in the host cell, which is able to carry out the preferred synthesis of new virus RNA. This RNA synthesis is supported by host factors, and an RNA minus-strand is formed. The following RNA replication affords a plus-strand. The process corresponds to a double feedback loop and involves the enzyme coded by the RNA matrix and the information present in the matrix in the form of a nucleotide sequence. Both factors contribute to the replication of the matrix, so that there is second-order autocatalysis (Eigen et al., 1982). 

In the early years of quantum theory, Hiickel developed a remarkably simple form of MO theory that retains great influence on the concepts of organic chemistry to this day. The Hiickel molecular orbital (HMO) picture for a planar conjugated pi network is based on the assumption of a minimal basis of orthonormal p-type AOs pr and an effective pi-Hamiltonian h(ctT) with matrix elements... 

The subsurface liquid phase generally is an open system and its composition is a result of dynamic transformation of dissolved constituents in various chemical species over a range of reaction time scales. At any particular time the liquid phase is an electrolyte solution, potentially containing a broad spectrum of inorganic and organic ions and nonionized molecules. The presently accepted description of the energy characteristics of the liquid phase is based on the concept of matrix and osmotic potentials. The matrix potential is due to the attraction of water to the solid matrix, while the osmotic potential is due to the presence of solute in the subsurface water. 

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