Organic matrix embedding

FIGURE 19.15 A photomicrograph of the cross section of the mother-of-pearl lining a mollusk shell. The composite material making up mother-nf-pearl consists of flat crystals of calcium carbonate embedded in a tough, flexible organic matrix that resists cracking. 

Star-shaped multi-porphyrin arrays have been constructed to mimic energy funneUng in photosynthesis. These dendrimers contain free-base porphyrin cores (Pfb) connected to four dendrons consisting of 1,3, or 7 zinc-metallated porphyrins (Pzn) embedded in an organic matrix coimected by ether linkages (Scheme 21) [70,71]. The periphery consists of methoxy-terminated poly(aryl ether) dendrons. For comparison, cone-shaped arrays consisting of Pfb cores monosubstituted with Pz dendrons were also synthesized. 

Biofilms consist of surface-associated colonies of bacteria and are a major concern for implanted medical devices and in many diseases [120-122], Bacterial biofilms are highly organized communities embedded in an exopolysaccharide matrix, and contain several layers of bacteria with distinct functions. Biofilms grow slowly but efficiently to coat abiotic surfaces, and can eventually almost completely fill up narrow tubing. Because of the entrenched structure of biofilms, an antibiotic cannot penetrate deeply enough into the distant parts of the biofilm to kill all bacteria. Therefore, biofilms are difficult to remove mechanically or by means of antibiotics or disinfectants. 

Biofilms are more specifically groups of cells embedded in an organic matrix [44], Therefore, the cells which are actually participating in the removal processes are often protected from undesirable conditions in the bulk phase of a reactor. Biofilms can suitably adjust their internal environmental conditions (e.g., pH, temperature, oxygen or toxicants) to make their removal processes favourable [39]. 

Another technique, used by Figaro Engineering Inc. and others, is to coat an alumina tube with tin oxide in an organic matrix, such as stearic acid, and sinter at 400-700 °C. A porous film results. Electrodes at either end of the tube are printed on or embedded in the sintered oxide and a platinum heater coil is positioned inside the tube. 

Figure 4.31 Electronmicrograph of surface water colloids and organics. The colloids are embedded in an organic matrix.

The organizational level believed to control the swelling behavior of keratins is the secondary and tertiary structure of the intermediate filaments and the matrix [116, 117]. As indicated previously, the intermediate filaments consist of proteins containing alpha-helical segments embedded in the less organized matrix of high cystine content. 

When the dq>osition techniques described above are applied, the structure of the obtained film is the following metal grains are embedded in an organic matrix in the... 

Vertebrate skeletons are composed of an organic matrix with embedded mineral pardcles. The mineralized collagen fibril in mineralized tissues, such as bone or certain tendons, is a composite of collagen molecules and calcium phosphate mineral particles. It is typically 50-200 nm in diameter and represents the basic building block of bone material. 

The Shpol skii method is a powerful improvement. The spectra of many organic molecules embedded in a crystalline matrix of short-chain n-... 

The fundamentals of SSS are based on the theory of impurity centers in a crystal. The optical spectrum of an organic molecule embedded in a matrix is defined by electron-vibrational interaction with intramolecular vibrations (vibronic coupling) and interaction with vibrations of the solvent (electron-phonon coupling). Each vibronic band consists of a narrow zero-phonon line (ZPL) and a relatively broad phonon wing (PW). ZPL corresponds to a molecular transition with no change in the number of phonons in the matrix (an optical analogy of the resonance -line in the Mossbauer effect). PW is determined by a transition which is accompanied by creation or annihilation of matrix phonons. The relative distribution of the integrated intensity of a band between ZPL and PW is characterized by the Debye-Waller factor ... 

The shell consists of calcite crystals embedded in an organic matrix or framework of interwoven protein fibers and spherical masses (protein-mucopolysaccharide complex) in a proportion of 50 1. There are also small amounts of magnesium carbonate and phosphates. 

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