Tailor-made Methods

For large-scale recombinant production of bacterial polymers, non-polymer producing bacteria were exposed to biosynthesis pathways. Polymers such as PHA, CGP (cyanophycin granule peptide), HA (hyaluronic acid), and PGA [poly-y-glutamate] were produced by these methods [89, 85-96]. For example, recombinant E.coli [89] was fermented for the lai e-scale production of PHA [89]. In addition the PHB biosynthesis genes of Ralstonia eutropa were harbored in E.coli to produce poljmers such as PHA composed of (R)-S-hydroxybutyrate and (R)-3-hydroxyvalerate and/or (R)-3-hydroxyhexanoate which showed preferable properties for use in industrial applications [97-99, 85-96]. 

The cell as a biosynthesis machine can use cheap carbon sources (waste products) as precursor substrates to produce bacterial polymers. However, the in vitro synthesis of biopolymers requires costly purified key enzymes and precursor molecules such as ATP, coal, coal bolsters, and nucleotide sugars or sugar acids to synthesize polymers such as PHA, cellulose, alginate, and PGA. Consequently, these polymers have limited commercial applicability due to their very high production costs. It is estimated the production of PHB by in vitro synthesis would amount to a cost of around US 286,000 per gram of PHB whereas, bacterial production of PHB was estimated to cost about 0.0025 per gram of PHB, and this is still 5-10 times as expensive to produce as the respective petroleum-based polymers. 

One of the more recent and exciting developments is the production of PHB granules by the recombinant bacterial cell as tailor-made functionalized micro-or nano-beads in which specific proteins attached to the PHA core have been engineered to display various protein functions. 

Engineered PHA beads were utilized in high-affinity bio-separation [112-114], enzyme immobilization [115], protein production [116], diagnostics [117], and as an antigen delivery system [118] which is currently being commercialized [98, 69]. Poly [(R)-3-hydroxyalkanoates] (PHAs) biopolymers can be stored by bacteria, and are currently receiving much attention because of their potential as renewable and biodegradable plastics. The best known representatives are poly (hydroxybutyrate) and its copolymers with hydroxyvalerate, which have been commercialized under the trademark Biopol . 

In addition to these rigid materials, the elastomeric medium-chain-length PHAs produced by fluorescent Pseudomonas are now emerging which can be cross-linked by conventional techniques to yield a biodegradable rubber. A typical application of this material would be a paper coating. 

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Ein weiterer Weg fur die Racemat-Auflosung besteht nach Curti und Colombo (13) in der Tailor-Made-Methode , d.h. ein optischer Antipode wird bci dcr Kieselgelfallung inkorporiert und wieder ausgcwaschen, wonach das Gel selektiv aufnahmefahig wird. Vgl. auch Reed und Rogers (50). 

Since the accuracy required to solve chemical problems — such as clarifying a reaction mechanism — is smaller than the accuracy that required for high-resolution spectroscopy, tailor-made methods have been devised. One example is the relativistic DKH-CASSCF/CASPT2+SO approach [1158-1160]. In view of the limited reliability of the CASSCF wave function (due to the limited size of the active space), we may well combine this ansatz with a one-component DKH Hamiltonian and sacrifice, to a certain extent, accuracy for feasibility. Dynamic correlation effects can be considered in a subsequent... 

If it is known that a drug must bind to a particular spot on a particular protein or nucleotide, then a drug can be tailor-made to bind at that site. This is often modeled computationally using any of several different techniques. Traditionally, the primary way of determining what compounds would be tested computationally was provided by the researcher s understanding of molecular interactions. A second method is the brute force testing of large numbers of compounds from a database of available structures. 

The realization of sensitive bioanalytical methods for measuring dmg and metaboUte concentrations in plasma and other biological fluids (see Automatic INSTRUMENTATION BlosENSORs) and the development of biocompatible polymers that can be tailor made with a wide range of predictable physical properties (see Prosthetic and biomedical devices) have revolutionized the development of pharmaceuticals (qv). Such bioanalytical techniques permit the characterization of pharmacokinetics, ie, the fate of a dmg in the plasma and body as a function of time. The pharmacokinetics of a dmg encompass absorption from the physiological site, distribution to the various compartments of the body, metaboHsm (if any), and excretion from the body (ADME). Clearance is the rate of removal of a dmg from the body and is the sum of all rates of clearance including metaboHsm, elimination, and excretion. 

A more quantitative and lengthy method, but still very useful for checking of the type required here is the Smith-Brinkley method (Reference 5). It uses two sets of separation factors for the top and bottom parts of the column for a fractionator or reboiled absorber and one overall separation factor for a simple absorber. The method is tailor-made for analysis of a column design or a field installed column. The Smith-Brinkley method starts with the column parameters and calculates the resulting product compositions unlike other methods that require knowing the compositions to determine the required reflux. 

The purpose of this paper is to thoroughly discuss the ability of anionic living polymerization methods to yield tailor-made polymers, and to discuss a number of examples of structures that have been obtained by these methods and adequately characterized. 

Interest in anionic polymerizations arises in part from the reactivity of the living carbanionic sites4 7) Access can be provided to polymers with a functional chain end. Such species are difficult to obtain by other methods. Polycondensations yield ro-functional polymers but they provide neither accurate molecular weight control nor low polydispersity. Recently Kennedy51) developed the inifer technique which is based upon selective transfer to fit vinylic polymers obtained cationically with functions at chain end. Also some cationic ring-opening polymerizations52) without spontaneous termination can yield re-functional polymers upon induced deactivation. Anionic polymerization remains however the most versatile and widely used method to synthesize tailor made re-functional macromolecules. 

In 1839, Charles Goodyear discovered that sulfur could cross-link polymer chains and patented the process in 1844 [1]. Since then rubber became a widely usable material. By the year 1853, natural rubber (NR) was in short supply. So attempts were made to undo what Goodyear had accomplished. Goodyear himself was involved in trying to reclaim vulcanized rubber to overcome the shortage of NR. Later, as a consequence of World War I, Germany introduced synthetic rubbers, namely the Buna rubbers, which raised the curiosity of polymer chemists all over the world. Subsequently, synthetic rubbers with tailor-made properties were born. This was followed by the discovery of new methods and chemicals for vulcanization and processing. It is obvious... 

Considering all given factors, ROM polymerisation can now be identified as the polymerisation method of choice for the synthesis of highly defined, tailor-made specialty polymers. 

For reproducible expression analysis and protein quantification MS methods based on isotopic labeling are available. They were designed in conjunction with two or more dimensional chromatographic peptide separation coupled online to MS and require advanced bioinformatics input to analyze the complex data sets in a reasonable time frame. This is also true for the alternative fluorescence-based technology of differential gel electrophoresis (DIGE Fig. 10.6) with tailor-made software which allows statistical validation of multiple data sets. 

The physicochemical nature of the oil phase components in a cosmetic emulsion, the emollients, determines the skin-care effects, such as smoothing, spreading, sensorial appearance. Test methods have been developed to characterize and classify the numerous emollients available on the market, such as silicones, paraffins, and oleochemical-based products. The latter include glycerides, esters, alcohols, ethers, and carbonates with tailor-made structures, depending on the performance needed (Table 4.8). However, especially with regard to additional effects, there is still a demand for new products with unique performance properties. 

The current method of drug discovery commences with the study of how the body functions, in both normal and abnormal cases afflicted with diseases. The aim is to break down the disease process into cellular and molecular levels. An understanding of the status of genes and their associated proteins would help to pinpoint the cause of the disease. Drugs can be tailor-made to attack the epicenter of diseases. In this way, more specific (fewer side effects) and effective (high therapeutic index, see Section 5.2) drugs can be discovered and manufactured to intervene or restore the cellular or molecular dysfunction. 

Although the word processing is normally reserved for the method of manufacture of any finished article it is important to recognise that the word can also describe the preparation or synthesis of the material. Thus in the polymer field it can range from improved methods of synthesis of polymers with tailor made properties (see Section 5.5) to improved methods of dispersion or improved methods of extrusion. Typical technological uses are shown in Tab. 5.25. 

The work discussed in the previous paragraphs provides the framework for the prediction of crystal habit from internal structure. The challenge is to add realistic methods for the calculation of solvent and impurities effects on the attachment energies (hence the crystal habits) to allow this method to provide prediction of crystal habit. Initial attempts of including solvent effects have been recently described (71. 721. The combination of prediction of crystal habit from attachment energies (including solvent and impurity effects) and the development of tailor made additives (based on structural properties) hold promise that practical routine control and prediction of crystal habit in realistic industrial situations could eventually become a reality. 

Mixed solid fertilizers can be made by either direct granulation methods (40%) or bulk blending (40%). Bulk blending is made by mechanical mixing of the separate granular intermediate materials. It is usually done in small plants near the point of use. This technique is employed because the fertilizer can be tailor-made to fit the exact requirements of the user. Fluid or liquid fertilizers (clear, suspension, and slurry) account for 20% of all NPK mixed fertilizers. 

ILs can also serve as tools for the MS itself. The introduchon of the ILMs for MALDI MS has opened the way to a number of new applicahons for this method. A number of theoretical studies are necessary in order to fully understand the properties of the ILMs [36]. The basic processes of IL-MALDI are still only partially understood. Therefore, basic work remains to be done to explain theoretical aspects. The wide field of already indicated and other shll unknown applications of the ILM seems to legitimate these efforts. Up to now, no consistent relationships have been found between the composition of an ILM and its ability to serve as a good matrix—a situahon which is comparable to all other substances used as matrices. A deeper understanding of the theoretical background of the ILM is the prerequisite for a possible tailor-made creation of new matrices in the future. 

The need for well defined polymer species of low polydls-perelty and of known structure arises from the Increasing Interest In structure-properties relationship In dilute solution as well as In the bulk. A great variety of methods have been attempted, to synthesize so-called model macromolecules or tailor made polymers-over the past 20 years. The techniques based on anionic polymerization, when carried out In aprotic solvents, have proved best suited for such synthesis, because of the absence of spontaneous transfer and termination reactions that characterize such systems. The "living 1 polymers obtained are fitted at chain end with carbanionic sites, which can either Initiate further polymerization, or react with various electrophilic compounds, intentionally added to achieve functionalizations. Another advantage of anionic polymerizations is that di-functlonal Initiators are available, yielding linear polymers fitted at both chain ends with carbanionic sites. In this paper we shall review the various utility of anionic polymerization to the synthesis of tailor made well defined macromolecules of various types. 

Moreover, star shaped polymers, which have p branches of known length connected by one of their ends to a central nodule are also of interest. The size of the nodule should be kept small with respect to the whole star molecule. The methods developed to synthesize these tailor made polymers have been reviewed recently. ... 

Star-shaped macromolecules have also been synthesized by using the monofunctional "living" precursor as an Initiator for the polymerization of a small amount of a divinyl monomer. A small crosslinked nodule is formed, which is connected with the p chains that have contributed to Its Initiation. It turns out that fluctuations on the value of p within a sample remain rather small, and consequently the star polymers obtained by this method can also be considered as tailor-made polymers. Recently star molecules with deuterium labeled central nodule have been synthesized according to the... 

The main limitation of these methods is the rather small number of monomers that undergo anionic polymerizations without transfer or termination steps. Nevertheless, research on the various applications of anionic polymerization as an efficient tool for the synthesis of tailor made polymers has been pursued very actively over the past 20 years, and it has yielded a great number of results of significance which has also opened a broad field of potential applications. 

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