Chemical imprinting

The abundance patterns of individual stars of different ages and environments enable us to unlock the evolutionary history of galaxies. Many physical characteristics of a galaxy may change over time, such as shape and colour, however the metal content and abundance ratios of stellar atmospheres are not so easy to tamper with. Stars retain the chemical imprint of the interstellar gas out of which they formed, and metals can only increase with time. This method to study galaxy evolution has been elegantly named Chemical Tagging [2],... 

The volcanic layer dating has been extended by stratigraphic correlation of diagnostic chemical imprints of volcanic ash dated on land adjacent to the deep-sea sediments of eastern Africa (Brown et al., 1992). 

A second example of chemical imprinting has been observed in the study of hexa-tertiarybutyl-decacyclene adsorption on the Cu(llO) surface (Fig. 4.11) [39, 40]. The structure of hexa-tertiarybutyl decacyclene is shown in Fig. 4.11a, b. Although the molecule is nominally flat, each of its three blades rotates slightly to reduce repulsions between the adjacent tertiary butyl groups, thus giving the... 

New evidence indicates that chemical imprinting in sea turtles will have to be even more phenomenal than previously imagined if it indeed occurs. Studies on predicted age of sexual maturity suggest 15-35 or more years for earliest maturation in green and loggerhead sea turtles (Balazs, 1980 ... 

Limpus and Walter, 1980). If chemical imprinting to the natal beach occurs, it surely must be the most extreme case of imprinting in the animal kingdom. The hatchling would have to learn chemical cues available perinatally during a few days or weeks at most, and as an adult (15-35 years later) discriminate these cues for the first time from many others. 

Grassman, M. A., 1984, The Chemosensory Behavior of Juvenile Sea Turtles Implication for Chemical Imprinting, Ph.D. dissertation, Texas A M University. 

Organically modified silicates, particularly Ormosils, may be designed to contain mixed functionalities within close proximity, and these can complement matching groups on the imprint, thus obtaining delicate chemical imprint rather than physical shaping alone. 

Figure 1.8. Left Sinularia flexibilis coral (above center) inhibiting the growth of neighboring hard corai Pavona cactus (below) along a gradient of distance between the two (photo S. La Barre). Right Longitudinal sedion of coral ("Stylophora pistillataj and its characteristic chemical imprint (photo F. Mohamadi)...

Bulk and surface imprinting strategies are straightforward tools to generate artificial antibodies. Combined with transducers such as QCM (quartz crystal microbalance), SAW (surface acoustic wave resonator), IDC (interdigital capacitor) or SPR (surface plasmon resonator) they yield powerful chemical sensors for a very broad range of analytes. 

Due to the very flexible synthetic approach, imprinted layers are highly suitable for sensor measurements in complex mixtures Sensor coatings consisting of a carbonic-acid-imprinted sol-gel material e.g. incorporate oxidative degradation products from engine oil leading to a chemical lubricant sensor. 

The development of highly selective chemical sensors for complex matrixes of medical, environmental, and industrial interest has been the object of greate research efforts in the last years. Recently, the use of artificial materials - molecularly imprinted polymers (MIPs) - with high recognition properties has been proposed for designing biomimetic sensors, but only a few sensor applications of MIPs based on electrosynythesized conductive polymers (MIEPs) have been reported [1-3]. 

The current trend in analytical chemistry applied to evaluate food quality and safety leans toward user-friendly miniaturized instruments and laboratory-on-a-chip applications. The techniques applied to direct screening of colorants in a food matrix include chemical microscopy, a spatial representation of chemical information from complex aggregates inside tissue matrices, biosensor-based screening, and molec-ularly imprinted polymer-based methods that serve as chemical alternatives to the use of immunosensors. 

As a consequence one might expect that the future needs to rely on hybrid elements which arise from advanced UV-and electron-beam lithography, from imprint techniques or automated and parallelized nanomanipulation techniques, like dip-pen lithography or focused ion-beam techniques in combination with supramolecular approaches for the assembly of molecular inorganic/organic hybrid system. Nevertheless, it is evident for any kind of chemical approach that falling back onto the present-day... 

The abundance ratios found in the photospheres of our target stars are imprints of the explosions of the first SNe II or even more massive stars. At very low metallicities there is a reasonable hope that the SNe which have polluted the environment were themselves primordial objects. In former papers on the chemical composition of very metal poor stars, some accent was put on trends of abundance ratios with metallicity ( McWilliam et al.[6], Norris et al. [8]). Such was the case for [Mn/Fe], or [Cr/Fe] decreasing with decreasing metallicity, or... 

Molecularly imprinted polymers have recently attracted much attention because they are denoted as artificial antibodies which are made from simple chemical components via polymerization and can be used for the preparation ofbiomimetic sensors, affinity separation matrices, catalysts, etc. (Figure 1). 

A major concern of DEA special agents is the identification of the source of drug evidence. One of the methods they use to meet this requirement is through ballistics examinations of tablets. A ballistics examination, in the sense used here, is a combination of in-depth chemical analysis and tool-mark examination of tablets and capsules for the purpose of identifying the manufacturer of the drug. The technique consists of accurate measurements of size scoring, imprints, or bevels the microscopic examination of the imperfections... 

ORMOSIL are chemical sponges they adsorb and concentrate reactants at their surface, thereby enhancing reaction rates and sensitivity (in sensing applications). ORMOSIL-imprinted materials with a suitable chiral template such as a surfactant or a protein selectively adsorb (and detect) external reactants. A remarkable example is provided by thin materials that are generally enantioselective, namely where the chirally imprinted cavities can discriminate between enantiomers of molecules not used in the imprinting process, and completely different from the imprinting ones. 

To prepare artificial enzymatic systems possessing molecular recognition ability for particular molecules, molecular imprinting methods that create template-shaped cavities with the memory of the template molecules in polymer matrices, have been developed [22, 30-35] and established in receptor, chromatographical separations, fine-chemical sensing, etc. in the past decade. The molecular... 

Broecker, W.S. (1974), "Chemical Oceanography", expecially Chapters 1 (Internal Cycling and Throughput) and 2 (The Sedimentary Imprint), Hartcourt Brace Jovanovich, New York. 

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