INDEX recent developments

B. North, "Indexable Metalcutting Inserts—A Review of Recent Developments," Proceedings of the 1 st International Conference on the Behavior of Material in Machining, Nov. 8—10, 1988, Stratford-upon-Avon, The Institute of Metals, Paper 35, 1988. 

The use of cycle index sums, mentioned above, is a powerful technique for enumeration, and a comparatively recent development of Polya theory. It will be instructive to consider a simple example... 

Thin-layer chromatography (TLC) is used both for characterization of alcohol sulfates and alcohol ether sulfates and for their analysis in mixtures. This technique, combined with the use of scanning densitometers, is a quantitative analytical method. TLC is preferred to HPLC in this case as anionic surfactants do not contain strong chromophores and the refractive index detector is of low sensitivity and not suitable for gradient elution. A recent development in HPLC detector technology, the evaporative light-scattering detector, will probably overcome these sensitivity problems. 

CoMSIA (comparative molecular similarity index analysis) is a recent development from CoMFA and does not suffer from the alignment problem. It has been used to model hERG potassium channel inhibition by drugs [59] and the toxicity of phenylsulfonyl carboxylates [60], organophosphates [61], and polybrominated diphenyl ethers [62], with results comparable to those from CoMFA. 

Recent developments and prospects of these methods have been discussed in a chapter by Schneider et al. (2001). It was underlined that these methods are widely applied for the characterization of crystalline materials (phase identification, quantitative analysis, determination of structure imperfections, crystal structure determination and analysis of 3D microstructural properties). Phase identification was traditionally based on a comparison of observed data with interplanar spacings and relative intensities (d and T) listed for crystalline materials. More recent search-match procedures, based on digitized patterns, and Powder Diffraction File (International Centre for Diffraction Data, USA.) containing powder data for hundreds of thousands substances may result in a fast efficient qualitative analysis. The determination of the amounts of different phases present in a multi-component sample (quantitative analysis) is based on the so-called Rietveld method. Procedures for pattern indexing, structure solution and refinement of structure model are based on the same method. 

Environment Canada recently developed an evaluation system based on effluent toxicity testing, capable of ranking the environmental hazards of industrial effluents [185]. This so-called Potential Ecotoxic Effects Probe (PEEP) incorporates the results of a variety of small-scale toxicity tests into one relative toxicity index to prioritize effluents for sanitation. In the index no allowance has been made for in-stream dilution, therefore the acmal risk for environmental effects is not modeled. The tests performed on each effluent are the following bacterial assay [V.fisheri (P. phosphoreum), Microtox], microalgal assay S. capricornutum) crustacean assay (C. dubiay, and bacterial genotoxicity test E. coli, SOS-test). 

More recent developments in this country have included synthesis of relatively stable oils of low volatility, low pour point, and high viscosity index by esterification of octyl alcohols, such as 2-ethylhexanol, with dibasic acids such as adipic acid and sebacic acid (3). Octyl alcohols may be synthesized from petroleum hydrocarbons via the oxo process. Although of relatively high cost, these synthetic oils find general application in making greases for lubrication of antifriction bearings and instruments in aircraft. 

There have been many developments in the chemistry of the 1,3,5-triazines since the comprehensive reviews of Smolin and Rapoport (59HC(13)1) and Modest (B-61MI22000, p.627). It is impossible to include all the vast range of 1,3,5-triazines reported in the literature 138 pages of the Compound Index in the Ninth Collective Index of Chemical Abstracts are dedicated to this system. This review will concentrate on the more important recent developments of 1,3,5-triazine chemistry, and reference will be made to previous reviews, or typical papers, to illustrate the better-known aspects of the subject. 

Various reactivity indices have been derived for benzenoid hydrocarbons from the following purely topological approaches the Huckel model (HMO), first-order perturbation theory (PMO), the free electron MO model (FEMO), and valence-bond structure resonance theory (VBSRT). Since many of the indices that have been known for a long time (index of free valence Fr, self-atom polarizability ir , superdelocalizability Sr, Brown s index Z, cation localization energy Lr+, Dewar reactivity number Nt, Brown s para-localization energy Lp) have been described in detail by Streitwieser in his well-known volume [23] we will refer here only to some more recent developments. 

Porphobilinogen and Studies of Its Biosynthesis, ft. Neier. Synthesis and Cycloaddition Reactions of Iso-Condensed Heteroaromatic Pyrroles, C. K. Sha. Azacyclopentadienyl Metal Compounds Historical Background and Recent Advances, C. Janiak and N. Kuhn. Recent Developments in the Synthesis of Marine Pyridoacridine Alkaloids, A. M. Echavar-ren. Alkaloid Synthesis Using 1-Acylpyridinium Salts as Intermediates, D. L. Comins and S. P. Joseph. Index. S S... 

Classical LC detectors (refractive index, fixed wavelength UV absorbance at 254 or 280 nm) have lacked the sensitivity to allow direct analysis of cannabi-noids in biological fluids. However, recent development of variable wavelength absorbance detectors extending into the 195-220nm UV region and of fluorescence detectors for HPLC led the authors to initiate... 

The article reports investigations of the topological properties of benzenoid molecules which the author has performed in the last 20 years. Emphasis is given on recent developments and other scientists contributions to these researches. Topics covered in recent books and reviews are avoided. The article outlines spectral properties, some aspects of the study of Kekule and Clar structures, the Wiener index as well as a number of graphs derived from benzenoid systems (inner dual, excised internal structure, Clar graph, Gutman tree, coral and its dual). 

Recent Developments in Isoxazole Chemistry N. K. Kochetkov and S. D. Sokolov Author Index—Subject Index... 

A recent development is the Super Index , a subject index covering chapters of all published volumes, which will soon be available via the Springer Home-page http //www.springer.de or http //www.springer-ny.com or http //Link. springer.de. 

It may be of interest to outline relatively recent developments. On the basis of a comprehensive analysis of volcanic chronology since 1500 AD, Lamb (1970) had introduced a criterion, the Dust Veil Index (DVI), for relating empirically the climatic effects to the characteristics of the eruption. The DVI was expressed with three alternative formulae, claimed to be equivalent, each expression being the product of three quantities ... 

Access to all this information is provided by the Index Chemicus Registry System (ICRS), which contains records of new compounds and associated data on magnetic tape (6). Structures are described by the Wiswesser Line Notation (7), a system for describing chemical formulas in terms of a linear groups of symbols. A recent development is the ICRS Substructure Index (G5), which enables manual searches to be made for new chemical information, and is based on the occurrence of fragments of structures, the most common of which are illustrated as conventional structural diagrams. 

---