New techniques

Despite the reservations noted above, it would be improper if no comment at all were made on the future of new techniques. In general, the trends of the last few decades suggest that developments in spectroscopy, chromatography and biological methods will continue to take place. Some of these will be in the direction of improving the speed, sensitivity and resolution of existing techniques, others may be the establishment of entirely new methods. 

Of the other established methods one can be less certain. Electrochemical methods, other than ion selective electrodes, seem to be practised more in academic laboratories than industrial, and are prone to fundamental problems relating to electrode contamination and chemical interferences. Nuclear methods would seem to have reached their apogee (if one classifies radio immuno assay as biological rather than nuclear) and the same seems to be true of thermal methods. This is not to say that these methods will not continue to be used and to be important. It is a comment that despite the missionary work of numerous adherents of these methods, one notes in the large industrial laboratories much more application of and enthusiasm for spectroscopy, chromatography and biological methods. 

It is even more difficult to predict the future of kinetic methods. There is scope here for considerable development and they have many advantages they can be used for difficult mixtures, they are well suited for automation and kinetics is an integral part of every course in chemistry, so its principles are well understood. However, as yet, these methods have not become as widespread as one might expect.1 

1 Six years ago one of us vividly remembers a very distinguished analytical chemist predicting, during the course of a brilliant lecture on novel kinetic methods, that within 4-5 years a kinetic method would be first choice for the majority of analytical determinations. 

In two papers workers at Varian Associates Analytical Instrument Division, describe several methods for increasing the effective resolution of n.m.r. instruments (at the expense of decreased signal-noise ratio). All of the methods are illustrated by reference to the case of 

A new and little understood technique that is worthy of attention is chemically induced dynamic nuclear polarization (CIDNP). A hexane-ether solution containing w-butyl-lithium, n-butyl bromide and diphenylacetylene, gives a transient spectrum resembling that of but-l-ene in which some of the lines are inverted. The authors ascribe the phenomena to the presence of free-radical intermediates, although the lines show no evidence of broadening due to paramagnetic induced relaxation. See also ref. 7a. 

The benefits of working with superconducting magnet n.m.r. instruments operating at a proton frequency of 220 Me./sec. has been applied to work on proteins differences in the spectra of native and denatured forms of ribonuclease, lysozyme, and cytochrome c have been detected, and nearest-neighbour base frequency ratios have been determined in single stranded DNA.  

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The pressure equipment directive was adopted by the European Parliament and the European Council in May 1997. It harmonises the national laws of the 15 Member States of the European Union relating to equipment subject to the pressure risk. That directive is one of the series of technical harmonisation directives such as for machinery, medical devices, simple pressure vessels, gas appliances and so on, which were foreseen by the Communities programme for the elimination of technical barriers to trade. It therefore aims to ensure the free placing on the market and putting into service of the equipment concerned within the European Union and the European Economic Area. At the same time it permits a flexible regulatory environment, allowing European industry to develop new techniques increasing thereby its international competitiveness. 

Lewis J W, Tilton R F, Einterz C M, Milder S J, Kuntz I D and Kliger D S 1985 New technique for measuring circular dichroism changes on a nanosecond time scale. Application to (carbonmonoxy)myoglobin and (carbonmonoxy)hemoglobin J. Rhys. Chem. 89 289-94... 

New Techniques for the Construction of Residue Potentials for Protein Folding... 

Intact peptides and proteins can be examined by a variety of new techniques, including MS/MS, dynamic FAB, APCI, and electrospray. Large masses of tens of thousands of Daltons can be accurately measured with unprecedented accuracy by electrospray. 

Seed Priming Bioreactors. Seed priming is a new technique enabling seeds suspended in an osmotica to imbibe moisture and thus be... 

Biopolymer Extraction. Research interests involving new techniques for separation of biochemicals from fermentation broth and cell culture media have increased as biotechnology has grown. Most separation methods are limited to small-scale appHcations but recendy solvent extraction has been studied as a potential technique for continuous and large-scale production and the use of two-phase aqueous systems has received increasing attention (259). A range of enzymes have favorable partition properties in a system based on a PGE—dextran—salt solution (97) ... 

Cyclization. Constmction of ben2otrifluorides from aHphatic feedstocks represents a new technique with economic potential. For example, l,l,l-trichloro-2,2,2-trifluoroethane [354-58-5] and dimethyl itaconate [617-52-7] form 4-methoxy-6-trifluoromethyl-2JT-pyran-2-one [101640-70-4] which is converted to methyl 3-(trifluoromethyi)ben2oate [2557-13-3] ixh. acetjdene or norbomadiene (125). 

Microscopists in every technical field use the microscope to characterize, compare, and identify a wide variety of substances, eg, protozoa, bacteria, vimses, and plant and animal tissue, as well as minerals, building materials, ceramics, metals, abrasives, pigments, foods, dmgs, explosives, fibers, hairs, and even single atoms. In addition, microscopists help to solve production and process problems, control quaUty, and handle trouble-shooting problems and customer complaints. Microscopists also do basic research in instmmentation, new techniques, specimen preparation, and appHcations of microscopy. The areas of appHcation include forensic trace evidence, contamination analysis, art conservation and authentication, and asbestos control, among others. 

A new technique referred to as the Hquid membrane method has been developed (69). Immobilized Hquid membranes are expected to become practical because of many advantages. 

Many antioxidants ia these classes are volatile to some extent at elevated temperatures and almost all antioxidants are readily extracted from their vulcanizates by the proper solvent. These disadvantages have become more pronounced as performance requirements for mbber products have been iacreased. Higher operating temperatures and the need for improved oxidation resistance under conditions of repeated extraction have accelerated the search for new techniques for polymer stabilization. Carpet backiag, seals, gaskets, and hose are some examples where high temperatures and/or solvent extraction can combine to deplete a mbber product of its antioxidant and thus lead to its oxidative deterioration faster (38,40). 

Laue Method for Macromolecule X-Ray Diffraction. As indicated above it is possible to determine the stmctures of macromolecules from x-ray diffraction however, it normally takes a relatively long period of data collection time (even at synchrotrons) to collect all of the data. A new technique, the Laue method, can be used to collect all of the data in a fraction of a second. Instead of using monochromated x-rays, a wide spectmm of incident x-rays is used. In this case, all of the reflections that ate diffracted on to an area detector are recorded at just one setting of the detector and the crystal. By collecting many complete data sets over a short period of time, the Laue method can be used to foUow the reaction of an enzyme with its substrate. This technique caimot be used with conventional x-ray sources. 

MacroHdes are obtained by controUed submerged aerobic fermentations of soil microorganisms. Although species of Streptomjces have dominated, species of Saccharopoljspora Micromonospora and Streptoverticillium are also weU represented. New techniques such as enzyme-linked immunosorbent assay (ELISA) based assays may prove beneficial for discovering new stmctures (464). 

Work on these and other new techniques continues, and it is hoped that a truly reliable, accelerated test or tests will be defined. 

A description of the scientific progress in the area and new techniques available. 

Power Supply Cookbook, Second Edition has been updated with the latest advances in the field of efficient power conversion. Efficiencies of between 80 to 95 percent are now possible using these new techniques. The major losses within the switching power supply and the modern techniques to reduce them are discussed at length. These include synchronous rectification, lossless snubbers, and active clamps. The information on methods of control, noise control, and optimum printed circuit board layout has also been updated. 

ICPMS is a relatively new technique that became usefiil and commercially available early in its development. As a result, the field is continually changing and grotving. The following is a summary of the directions of ICPMS instrumentation as described by three commercial instrument representatives. ... 

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