Biomedical applications. See

The most important xanthenes are the imino derivatives known as rhodamines, exemplified by rhodamine B (Cl Basic Violet 10) (3.23a), A. 543 nm and 552 nm and rhodamine 6G (Cl Basic Red 1) (3.23b), /L 530 and X 557 nm (Figure 3.11). These are intensively fluorescent dyes with quantum yields close to unity. Rhodamine 6G especially has found wide apphcation in dayhght fluorescent pigments (see section 3.5.2) and this ring structure has been much modified for use in many other outlets, especially as laser dyes (see section 3.5.3) and in biomedical applications (see section 3.5.6). 

Near-Infrared Dyes with Near-Infrared Fluorescence. This type is becoming more important, particularly in biomedical applications (see Chapter 6). Phthalo-cyanines and cyanines provide this type of fluorescence. 

A variety of alternative methods for preparing ReCp (CO)3 where Cp means a Cp ring substituted with bioactive molecules or with functions that enable binding of biomolecules, has been developed for biomedical applications (see Section 15). 

In addition to its importance in the production of animal glue, collagen is the basis for gelatin, which forms when collagen fibers are denatured as a result of heating and then get tangled up with each other. Collagen is also used for various biomedical applications, see also Denaturation Peptide Bond Proteins. 

PHAs are biocompatible as well as biodegradable and PHBV is used in biomedical applications (see Biodegradable Polymers, Medical Applications). One of its degradation products, butyric acid, is a mammalian metabolite found in low concentrations in humans. 

Micelle formation with amphiphilic graft and comb copolymers has received much less attention than that of block copolymers, although brush structures are gaining interest, mainly for biomedical applications (see Section 7.4). As already mentioned in Section 7.2, this is mainly due to the fact that these branched copolymers are not as well defined in structure, composition and molecular weight as the corresponding block copolymer, even if they are synthesized by controlled polymerization and macromonomer techniques. 

For a more in-depth discussion, see Dass, C. Chapter 1 in D. M. Desiderio, Ed. Mass Spectrometry Clinical and Biomedical Applications (Vol. 2). New York Plenum Press, 1994. 

Silk fibers or monolayers of silk proteins have a number of potential biomedical applications. Biocompatibility tests have been carried out with scaffolds of fibers or solubilized silk proteins from the silkworm Bombyx mori (for review see Ref. [38]). Some biocompatibility problems have been reported, but this was probably due to contamination with residual sericin. More recent studies with well-defined silkworm silk fibers and films suggest that the core fibroin fibers show in vivo and in vivo biocompatibility that is comparable to other biomaterials, such as polyactic acid and collagen. Altmann et al. [39] showed that a silk-fiber matrix obtained from properly processed natural silkworm fibers is a suitable material for the attachment, expansion and differentiation of adult human progenitor bone marrow stromal cells. Also, the direct inflammatory potential of silkworm silk was studied using an in vitro system [40]. The authors claimed that their silk fibers were mostly immunologically inert in short and long term culture with murine macrophage cells. 

The receptors of ecological interactions are still not well understood. In fact, many ecological studies have failed to demonstrate well-defined roles for natural products (Pawlik 1993). Most experimental evidence for natural product receptors derives from biomedical applications. Kahalalide F, for example, is a potent cytotoxic depsipeptide (see Sect. 1.3.2.3) initially found in the sacoglossan mollusc Elysia rufescens and later in the green alga it feeds upon (Hamann and Scheuer... 

In recent years, CNTs have been receiving considerable attention because of their potential use in biomedical applications. Solubility of CNTs in aqueous media is a fundamental prerequisite to increase their biocompatibility. For this purpose several methods of dispersion and solubilisation have been developed leading to chemically modified CNTs (see Paragraph 2). The modification of carbon nanotubes also provides multiple sites for the attachment of several kinds of molecules, making functionalised CNTs a promising alternative for the delivery of therapeutic compounds. 

Biomedical. Heart-valve parts are fabricated from pyrolytic carbon, which is compatible with living tissue. Such parts are produced by high temperature pyrolysis of gases such as methane. Other potential biomedical applications are dental implants and other prostheses where a seal between the implant and the living biological surface is essential. Plasma and arc-wire sprayed coatings are used on prosthetic devices, eg, hip implants, to achieve better bone/tissue attachments (see Prosthetic and biomedicaldevices). 

After the first successful attempts in 1928 to identify the active biochemicals found in antibacterial molds, followed the rediscovery of penicillin by Fleming, identification of its chemical structure by Hodgkin, and subsequent synthesis by Chain, Heatley, and Florey, which led to the commercial production of penicillin in the mid 1940s [1], Since then, other families of (3-lactam antibiotics have been developed [2, 3], and their massive use worldwide continues to be a forefront line of action against infectious pathogens [4-6]. In recent years, (3-lactams have found other biomedical applications, such as inhibitors of serine protease ([7, 8] for a review, see [9]) and inhibitors of acyl-CoA cholesterol acyltransferasa (ACAT) [10]. Encouraged by their bioactivity, the synthesis and chemistry of (3-lactam antibiotics have been the focus of active research, and chemical modification of some basic structures available from biosynthesis (semisynthetic approaches) as well as the discovery of fully chemical routes to de novo synthesis of (3-lactam... 

Bentazone, determination of 346 Biomedical applications 251-289 see also forensic applications Breakthrough volume 121, 123... 

HPLC-HRGC coupling 235-243 MDGC 217-231, 422 TLC 242-245 Food packaging 305-306 Forensic applications 407-429 see also biomedical applications Fragrance analysis see food analysis... 

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