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EnVision™ procedure

In contrast to the EPOS system, a modification of the highly sensitive two-step immunohistochemical EnVision system allows the detection of a broad spectrum of antigens in frozen sections in less than 13 min (Kammerer et al., 2001). In this study 38 out of 45 antibodies tested showed specific staining. In fact, the modified EnVision procedure allows the use of any suitable primary antibody, preferably monoclonal antibodies. Like the EPOS system, EnVision employs a dextran polymer coupled to horseradish peroxidase molecules for detection. No attempt was made to block endogenous peroxidase, nor was any antigen retrieval pretreatment used. Because of the very short incubation durations, a humid chamber is not required to avoid evaporation of immunoreagents. [Pg.139]

FIGURE 6.11. Step-by-step schematic diagram of the rapid EnVision procedure. RT = room temperature TBS = Tris-buffered saline (pH 7.4) H = Meyer s hematoxylin. Reproduced, with permission, from Kammerer et al. (2001). Copyright 2001 Histochemical Society. [Pg.140]

Although the previous protocol suggests it is not necessary to deprotonate the sulfonamide prior to exposure to the zinc carbenoid, a experimentally simpler procedure can be envisioned wherein the alcohol and promoter are deprotonated in a single flask (Fig. 3.15). In protocol IV, the alcohol and promoter are combined in flask A and are treated with diethylzinc, thus forming the zinc alkoxide and zinc sulfonamide. In sub-protocol IVa, this solution is transferred to flask C which contains the zinc carbenoid. Sub-protocol IVb represents the reversed addition order. Sub-protocol IVa is not only found to be the superior protocol in this sub-set, it is found to out-perform all of the previous protocols Despite the persistence of the induction period, a large rate enhancement over the uncatalyzed process is observed. This considerable rate enhancement also translates to a reduction in the overall reaction time when compared to sub-protocols la and Ilia. Selectivity rises... [Pg.130]

The asymmetric reduction of the benzoxathiin is very appealing because of its simplicity (Scheme 5.3). It was envisioned that intermediate 16 could be prepared from thiol-phenol 7 and bro moke tone 17. Scheme 5.8 summarized the synthesis for 16. The l,3-benzoxathiol-2-one 35 was prepared from 1,4-benzoquinone and thiourea following a literature procedure with minor modifications. Benzylation of 35 with benzyl bromide in the presence of KI gave benzyl ether 36 as a crystalline solid. It was observed that the benzylation gave better results when the reaction was run under anaerobic conditions. Hydrolysis of thiocarbonate 36 gave free thiophenol 7 which was used directly in the next reaction. [Pg.150]

By analogy with B-trialkylaminoborazi ne and polyborazine derived therefrom, the first route envisioned to poly(borylaminoborazine) was the thermal condensation of molecular precursors under a convenient atmosphere. As detailed earlier the innovative idea behind this procedure is to tailor the polymeric precursor structure by increasing the distance between the two borazinic rings. For that purpose, we explored... [Pg.183]

Sulfur trioxide is not only much cheaper than hexachloroplatinate, but the sulfur dioxide formed can in principle be converted back to sulfur trioxide by oxidation with air. Methylbisulfate can be hydrolyzed to methanol, and so a complete cycle that converts CH4 and 02 into CH3OH can be envisioned. Overoxidation of methane to C02 - a major side reaction of many procedures - was relatively limited in the... [Pg.261]

The dominant tendency of my studies has been not so much to obtain and describe organic compounds but... to penetrate their mechanisms.. . . For undertaking this kind of problem, the classic methods of organic chemistry are far from sufficient. Physicochemical procedures become more and more necessary. I have been led to use especially optical methods (the Raman effect and ultraviolet spectra) and electrochemical techniques (conductibility, electrode potentials, and especially polarography).. . . The notion of reaction mechanism led almost automatically to envisioning the electronic aspect of chemical phenomena. From 1927, and working in common with Charles Prevost, I have directed my attention on the electronic theory of reactions." 56... [Pg.170]

In retrospect, we envisioned a number of alternative catalyst systems. Although some of them appeared quite promising, the cost of raw materials, and/or the complexity of a process, or the unavailability of specific manufacturing equipment or procedures frequently militated against many attractive alternatives. [Pg.336]

Elimination of metal ions is a second major function of supported chelators. And a variety of conditions may be envisioned. Electroplating firms can be faced with the need to remove metal ions from solutions as part of an EPA-approved disposal protocol. A radiator shop may be faced with a need to remove waste zinc ion before allowing water to go into a sewer, in an effort to minimize the danger of killing bacteria used in sewage treatment procedures. The Berkeley Pit (vide infra) represents an outstanding example of the need to remove waste copper. [Pg.124]

Dry boxes also offer significant advantages over vacuum line techniques in the study of mixed-solvent systems. It is difficult to mix two different solvents accurately on a vacuum line. In a dry box, the procedure is rendered almost trivial. Definite advantages of a dry box can also be envisioned for electrochemistry in low-temperature molten salts, which are often very hygroscopic. [Pg.579]

A minor disadvantage of the modified EnVision system is that it requires primary antibody concentrations four- to tenfold higher than those used in the conventional immunohistochemical procedures. Another limitation of this modified method is that only two slides with two sections each can be processed at any one time. [Pg.139]

As stated by Manz, the pTAS was envisioned as a new concept for chemical sensing, needed since sensors at that time were not providing the best results in terms of selectivity and lifetime. Initially, the main reason for miniaturisation was to enhance the analytical performance of the device rather than to reduce its size. However, it was also recognised that a small scale presented the advantage of a smaller consumption of sample and reagents. Moreover, the total chemical analysis system scheme could provide an integration of several laboratory procedures such as sample preparation, filtration, preconcentration,... [Pg.827]

The Hantzsch synthesis of dihydropyridines represents a classical example of MCR, generating an array of diversely substituted heterocycles in a one-pot reaction procedure. Given that the reaction requires elevated temperatures and extended reaction times to proceed, acceleration of the process by microwave irradiation could be envisioned. Indeed, dielectric heating of aldehyde (aliphatic or aromatic) and 5 equivalents of /i-keloesler in aqueous 25% NH4OH (used both as reagent and solvent) at 140-150 °C for merely 10-15 min furnished 4-aryl-l,4-dihydropyridines in 51-92% yield after purification on a silica gel column [100]. The Hantzsch synthesis under reflux conditions ( 100 °C) featured a remarkably longer time (12 hours) and lower yields (15- 72%). To demonstrate the suitability of the procedure for the needs of combinatorial chemistry, a 24-membered library of 1,4-dihydropyridines (DHP) was prepared (Scheme 36). [Pg.80]

Treatment of a dendritic polyester 5 with a dendritic polyamine 6 is perhaps the simplest example of coupling between two dissimilar cascade macromolecules.178-801 Scheme 9.2 illustrates some potential products (i.e., 7 and 8) available by this general procedure, as well as a continuation of surface amidation to afford polymeric species such as random network 9. As envisioned, it would be difficult to stop this procedure after the formation of a single amide bond, due to the close proximity of adjacent ester—amine groups. [Pg.228]


See other pages where EnVision™ procedure is mentioned: [Pg.139]    [Pg.139]    [Pg.67]    [Pg.128]    [Pg.159]    [Pg.572]    [Pg.284]    [Pg.95]    [Pg.64]    [Pg.128]    [Pg.177]    [Pg.45]    [Pg.21]    [Pg.197]    [Pg.15]    [Pg.148]    [Pg.553]    [Pg.431]    [Pg.42]    [Pg.148]    [Pg.41]    [Pg.116]    [Pg.288]    [Pg.882]    [Pg.181]    [Pg.158]    [Pg.29]    [Pg.209]    [Pg.39]    [Pg.301]    [Pg.6]    [Pg.348]    [Pg.107]    [Pg.322]    [Pg.1189]    [Pg.65]   
See also in sourсe #XX -- [ Pg.58 , Pg.59 , Pg.60 , Pg.106 ]




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