Factor hindered

The relatively high prize of the enzymes is one factor hindering application of the method in practical scale. In this the work composition of the cambium and the effects of enzymes on isolated cambium were studied in order to determine the optimal enzyme composition for debarking. 

The chemoselectivity of the dioxirane oxyfunctionalization usually follows the reactivity sequence heteroatom (lone-pair electrons) oxidation > JT-bond epoxida-tion > C-H insertion, as expected of an electrophilic oxidant. Because of this chemoselectivity order, heteroatoms in a substrate will be selectively oxidized in the presence of C-H bonds and even C-C double bonds. In allylic alcohols, however, C-H oxidation of the allylic C-H bond to a,/ -unsaturated ketones may compete efficaciously with epoxidation, especially when steric factors hinder the dioxirane attack on the Jt bond. To circumvent the preferred heteroatom oxidation and thereby alter the chemoselectivity order in favor of the C-H insertion, tedious protection methodology must be used. For example, amines may be protected in the form of amides [46], ammonium salts [50], or BF3 complexes [51] however, much work must still be expended on the development of effective procedures which avoid the oxidation of heteroatoms and C-C multiple bonds. 

A newly described procedure for complete enzymic hydrolysis of proteins and peptides (Brown and Wold 1973) makes use of several proteases which are covalently attached to insoluble supports (Cuatrecasas et al. 1968). The advantages of using these enzymes in the insoluble form are that the enzymes may be easily removed from the products, and there is little or no hydrolysis of the enzymes themselves which reduces the corrections for controls. One disadvantage of the insoluble proteases may be that the size of the insoluble particles introduces steric factors hindering the hydrolysis of large peptides or proteins. 

The methylene group adjacent to the ketone function in 4-phenyl-1,4-dihydrobenzo[f]isoquinolin-2(3H)-one is sufficiently activated to undergo reaction with benzaldehyde in the presence of sodium l dride in dimethylformamide. The 1-benzyl derivative results together with aromatised starting compound presumably steric factors hinder the condensation to scxne extent. 

A factor hindering the expansion of PAn chemistry to date has been the lack of a generic route to variously substituted derivatives. An exciting development in this respect is the recent synthesis of the novel poly(aniline boronic acid).138 Aromatic boronic acids are versatile chemical precursors, undergoing a wide range of transformations and this provides a facile route to a wide range of substituted PAn s that are difficult to synthesize directly from their respective monomers. This approach has been successfully demonstrated for the synthesis of poly(hydroxyaniline) and for poly(halogenoaniline).138... 

A worldwide acknowledged novel technology involves inactivation of antinutritive factors of soybean by microbiological methods. In the joint silage of a mixture of freshly harvested corn and raw soybean (CSM), under appropriate conditions, factors hindering the digestibility of nutrients of soybean can be inactivated in a bacterial process in a few weeks. 

The ammonolysis of perchlorotoluene cannot be achieved under moderate conditions. Ammonia in DMSO gives two chlorinated nitriles with ring-chlorine substitution by the amino group (Bandres, 1975). Steric shielding and the rather low nucleophilicity of ammonia are probably the factors hindering such ammonolysis. 

The second factor hindering the development of starch-based material for plastics has been the high cost of the technology required to solve the technical issues, ultimately reflected in the cost of the finished products. 

The use of landfill sites seems to be the most important practice used by the apparel industry to dispose the solid waste (Lamey and van Aardt, 2010). Lack of technology and suitable equipment are considered to be the major factors hindering recycling. Consumers should be encouraged to use recyclable materials and appreciate the benefits it could generate to them as well as the generations to come. 

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