Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Repetitive origin

Detergent Applications. The primary function of FWAs in the laundry process is to whiten fabric load and maintain the original appearance of the white, laundered articles. Laundering is characterized by repeated appHcation to the same item. Fluorescent whiteners used in this repetitive process have to compensate for the reduction in whiteness and contribute toward prolongation of the usefiil life of the textile material. [Pg.119]

Some six hundred structures of naturally occurring carbogenic molecules appe on the pages which follow, together with the name of each compound and references to the original literature of successful chemical synthesis. Thus, Part Three of this book is effectively a key to the literature of chemical synthesis as applied to the complex molecules of nature. The survey does not include oligomeric or polymeric structures, such as peptides, proteins, carbohydrates and polynucleotides, which fall outside the scope of this book because they can be assembled by repetitive procedures. [Pg.359]

The same author has shown by repetition of the early experiments already referred to (p. 507) that when yohimbine hydrochloride is distilled with zinc dust there is formed in addition to harman (XVII), p-cresol, which must originate from ring E of the yohimbine formula (XIV) by inclusion of C as the methyl group. Witkop s formula for yobyrine (IV6) received prompt confirmation by Clemo and Swan s synthesis of this base by... [Pg.510]

Throughout the standard, various clauses reference the clause on quality records. To avoid repetition, the common requirements for quality records are assembled under one heading. The requirements, however, are not limited to those clauses in which this requirement is referenced as many other clauses refer to records. However, as all clauses will generate some documentary evidence it should not be assumed that all such documents are quality records. The requirements, however, apply only to original records and not to any copies other than those taken for security reasons or copies of subcontractor records. There are several types of document used in a quality system and only some are classified as quality records. As quality records are documents it might be assumed that the requirements of clause 4.5 on document and data control apply to quality records. As clause 4.16 is not cross referenced in clause 4.5 (except for clause 4.5.2.2), there is clearly no requirement for you to apply the requirements for document control to quality records. (See also Part 2 Chapter 5.) Figure 5.2 illustrates the difference between quality records and documents. [Pg.491]

The original objective of the synthetic work was the preparation of basic derivatives of the 3,1,4-benzoxadiazepine system (2) for animal testing. The basic ring system had been reported previously in the literature as the dehydration products of 2-acylaminobenzophenone oximes (1). Repetition of the work quickly cast doubt on the earlier structural assignment. Both the chemistry of the products and their spectral data suggested that the products were in fact quinazoline-3-oxides (3). ... [Pg.363]

The original scientific account of the preparation of this body stated that mcfa-isohutyl toluene was heated on a water-bath for twenty-four hours, with five times its weight of a mixture of sulphuric and nitric acids. The product was subjected to a repetition of the same treatment, so as to convert it into trinitro-butyl toluene, which crystallises from alcohol in white needles melting at 96° to 97°. It is insoluble in water, but soluble in organic solvents. Even in very dilute solutions this compound has a. [Pg.288]

In another study, the original repetitive Cio, (AGAGAGPEG)io, center was reconstructed into nine repeats of AGAGAGPEG with three distributed repeats of the RGD sequence. The new triblock protein, composed of acidic and basic terminal domains in addition to the reconstructed central block, has been shown to support adhesion, spreading, and polarization of human fibroblast cells [82]. Triblock polypeptides that facilitate antibody binding have also been reported [83]. [Pg.145]

Seizures originate in a group of neurons which do not have normal electrical behavior.12 Individual neuronal firing is prolonged and repetitive. This long, abnormal depolarization is called a paroxysmal depolarizing shift (PDS). [Pg.445]

The history of dendrimer chemistry can be traced to the foundations laid down by Flory [34] over fifty years ago, particularly his studies concerning macro-molecular networks and branched polymers. More than two decades after Flory s initial groundwork (1978) Vogtle et al. [28] reported the synthesis and characterization of the first example of a cascade molecule. Michael-type addition of a primary amine to acrylonitrile (the linear monomer) afforded a tertiary amine with two arms. Subsequent reduction of the nitriles afforded a new diamine, which, upon repetition of this simple synthetic sequence, provided the desired tetraamine (1, Fig. 2) thus the advent of the iterative synthetic process and the construction of branched macromolecular architectures was at hand. Further growth of Vogtle s original dendrimer was impeded due to difficulties associated with nitrile reduction, which was later circumvented [35, 36]. This procedure eventually led to DSM s commercially available polypropylene imine) dendrimers. [Pg.32]

Repetition of the original preparation [1] involving interaction of diethy-laminoethanol with fuming nitric acid, followed by vacuum distillation of excess acid, invariably caused explosions during this operation. A modified procedure without evaporation is described [2],... [Pg.838]

Induction of repetitive activity in the nervous system is the principal effect of pyrethroids. Repetitive activity originates from a prolongation of the transient increase in sodium permeability of the nerve membrane associated with excitation. All pyrethroids affect sodium channel gating in a similar manner, although Type II pyrethroids are significantly more neurotoxic than Type I pyrethroids. [Pg.1099]

In Kadanoff s [130, 131] two-dimensional block-spin model four neighbouring spins are assumed to have identical spins, either up or down, near the critical point. The block of four then acts like a single effective spin. The lattice constant of the effective new lattice is double the original lattice constant. The coherence length measured in units of the new lattice constant will hence be at half of its original measure. Repetition of this procedure allows further reduction in by factors of two, until finally one has an effective theory with = 1. At each step it is convenient to define renormalized block spins such that their magnitude is 1 instead of 4. The energy of such blocked spins is... [Pg.515]


See other pages where Repetitive origin is mentioned: [Pg.1971]    [Pg.2493]    [Pg.2936]    [Pg.1135]    [Pg.1972]    [Pg.573]    [Pg.1135]    [Pg.471]    [Pg.471]    [Pg.182]    [Pg.231]    [Pg.53]    [Pg.30]    [Pg.78]    [Pg.543]    [Pg.283]    [Pg.37]    [Pg.384]    [Pg.282]    [Pg.130]    [Pg.50]    [Pg.418]    [Pg.551]    [Pg.320]    [Pg.384]    [Pg.134]    [Pg.78]    [Pg.264]    [Pg.323]    [Pg.8]    [Pg.289]    [Pg.282]    [Pg.286]    [Pg.336]    [Pg.16]    [Pg.172]    [Pg.330]    [Pg.164]    [Pg.420]   
See also in sourсe #XX -- [ Pg.97 ]




SEARCH



Repetition

© 2024 chempedia.info