Sensitizing host

The primary advantage of CD complexation is to stabilize and protect sensitive host molecules, such as flavors, odors, or pharmaceuticals. CDs sharply reduce the volatility, chemical, thermal and photo reactivity of guest moleciiles. More recently, CDs have been used for separation of components in solution. For example, CDs can remove reactive components from fhiit juices to prevent oxidation or eUminate bitterness. Attachment of CDs to chromatographic supports provides chiral separation, selective component removal and modified chemical reactivity. A number of modified and pol3nnerized CD materials have gained acceptance as separation media (9). 

A similar but advanced approach using a sensitizing host, or receptor, has been reported very recently. Krische and coworkers synthesized a supramolecular host... 

For sensitized hosts, there can beantigens of human blood products, such as human serum albumin, penicillin drugs, or other therapeutic agentsJ ... 

Introduction into Antibiotic Sensitive Host cells (i.e., ampS)... 

A number of practical considerations caused us to favor derivatives of 1 over 2 in the search for a new mid-UV sensitizer 1. they are extremely common and the synthetic methodology has been well developed, 2. the 2-diazonaphthalene-l-one 1 chromophore seems to show better thermal stability than the isomer 2 and finally 3. the photosensitivity of derivatives of 1 is reported to be somewhat higher than comparable derivatives of 2 (5). The last two features will be important ingredients in defining the ultimate sensitivity of a (sensitizer-host) resist system. 

Classic absorption spectroscopy has been described in detail by Burns (1993), Rossman (1988) and many others. The key aspect that relates to luminescence is that the absorption spectmm indicates the energy level separations, i.e., the electronic stmcture, of the absorbing species. Once these are known, comparison with the excitation spectmm can indicate type of activator and type of sensitizer. Host lattice sensitization can also be determined in this way. 

A novel microlithographic application for photoinitiated polymerization involves the polymerization of a monomer and the locking-in of a plasma-sensitive host polymer so that plasma techniques can be used to carry out all-dry development, thus avoiding the problems of swelling and resolution limitation associated with standard resists. Some plasma-developable resists are described later in this section. 

The applications of solvent-tolerant strains in microbial production processes are at present limited, but two strategic options are currently available to use such bacteria. Relevant genes can be introduced into solvent-tolerant organisms in order to produce the required product. This approach has been followed successfully by J. Wery in our laboratory who employed an 1-octanol-aqueous system. Methylcatechol was produced from toluene by solvent tolerant P. putida S12. Alternatively, the efflux pump can be expressed in a suitable solvent-sensitive host which would then be more tolerant for a particular solvent. 

G. Proni, G. Pescitelli, X. Huang, K. Nakanishi, N. Berova, Magnesium tetraaryl porphyrin tweezer a CD-sensitive host for absolute configurational assignments of achiral carboxylic acids. J. Am. Chem. Soc. 125, 12914-12927 (2003)... 

Kowal, K. J., and Stollar, V., 1981, Temperature-sensitive host-dependent mutants of Sindbis virus. Virology 114 140. 

In the future, we can expect to have more guest-selective and sensitive host molecules derived from CD, and the CD-mediated assemblies of well-defined structures and functions. The studies using fluorescence techniques would provide valuable guides for designing the CD-derivatives and construction of the assemblies. Promises for this can be found in the several parts of this chapter. 

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