Crystal Violet, an Electronic Model Substance for Rubber and Related Olefins

1951 ◽  
Vol 24 (1) ◽  
pp. 169-181 ◽  
Author(s):  
G. J. van Veersen
Keyword(s):  
Crystal Violet ◽  
Electronic Structures ◽  
Radical Reaction ◽  
Test Tube ◽  
Chemical Agent ◽  
Blue Color ◽  
Electronic Model ◽  
Model Substance ◽  
Model Substances ◽  
Polar Reaction

Abstract It is shown that triphenylmethyl dyes like crystal violet can be used as model substances for rubber and related olefins. Arguments are given in support of the assumption that agents which react with rubber and related olefins in a polar manner cause a reversible shift in color from blue to yellow with crystal violet, whereas a fading of the blue color of crystal violet (if alkaline or reducing agents are excluded) points to a radical reaction. Since the electronic structures of donor olefins and crystal violet are considered and not the molecular structure, as usually is done in the choice of a model substance, these dyes have been named electronic model substances. Though crystal violet, as an electronic model substance cannot be used for the study of the overall reactions, information can often be obtained concerning the first step in a reaction of rubber with a certain chemical agent by means of a simple test-tube reaction with crystal violet. It was pointed out that the π-electron availability at the non-methylated carbon atom of the double bond in rubber and at the nitrogen atoms in crystal violet is probably of the same order. As an application of crystal violet as an electronic model substance for rubber, a polar reaction between sulfur and rubber is suggested as the first step in vulcanization.

Screening Test for the Diagnosis of Chronic Granulomatous Disease

PEDIATRICS ◽  
1969 ◽  
Vol 43 (1) ◽  
pp. 122-124
Author(s):  
Richard B. Johnston
Keyword(s):  
Chronic Granulomatous Disease ◽  
Screening Test ◽  
Test Tube ◽  
Nitroblue Tetrazolium ◽  
Blue Color ◽  
Granulomatous Disease ◽  
Latex Particles

Normal phagocytes suspended in plasma when mixed with latex particles for ingestion and nitroblue tetrazolium dye will reduce the dye to a blue color which may be easily seen in a test tube. This reaction depends on the release of enzymes from phagocytic lysosomal granules after phagocytosis. Since such release is deficient in patients with CGD, no blue color develops in the tube. This has proved to be a simple, reliable, screening test which should allow the more rapid and widespread diagnosis of CGD.

Nitrogen and Sulfur Transferases

2007 ◽  
Author(s):  
Perry A. Frey ◽  
Adrian D. Hegeman
Keyword(s):  
Steady State ◽  
Reaction Mechanism ◽  
Active Site ◽  
Reaction Mechanisms ◽  
Radical Reaction ◽  
Amino Group ◽  
Steady State Kinetics ◽  
Ping Pong ◽  
Polar Reaction

Unlike other group transfer reactions in biochemistry, the actions of nitrogen transferring enzymes do not follow a single unifying chemical principle. Nitrogen-transferring enzymes catalyze aminotransfer, amidotransfer, and amidinotransfer. An aminotransferase catalyzes the transfer of the NH2 group from a primary amine to a ketone or aldehyde. An amidotransferase catalyzes the transfer of the anide-NH2 group from glutamine to another group. These reactions proceed by polar reaction mechanisms. Aminomutases catalyze 1,2-intramolecular aminotransfer, in which an amino group is inserted into an adjacent C—H bond. The action of lysine 2,3-aminomutase, described in chapter 7, is an example of an aminomutase that functions by a radical reaction mechanism. Tyrosine 2,3-aminomutase also catalyzes the 2,3-amino migration, but it does so by a polar reaction mechanism. In this chapter, we consider NH2-transferring enzymes that function by polar reaction mechanisms. Transaminases or aminotransferases are the most extensively studied pyridoxal-5'-phosphate (PLP)–dependent enzymes, and many aminotransferases catalyze essential steps in catabolic and anabolic metabolism. In the classic transaminase reaction, aspartate aminotransferase (AAT) catalyzes the fully reversible reaction of L-aspartate with α-ketoglutarate according to fig. 13-1 to form oxaloacetate and L-glutamate. Like all aminotransferases, AAT is PLP dependent, and PLP functions in its classic role of providing a reactive carbonyl group to function in facilitating the cleavage of the α-H of aspartate and the departure of the α-amino group of aspartate for transfer to α-ketoglutarate (Snell, 1962). PLP in the holoenzyme functions in essence to stabilize the α-carbanions of L-aspartate or L-glutamate, the major biological role of PLP discussed in chapter 3. The functional groups of the enzyme catalyze steps in the mechanism, such as the 1,3-prototropic shift of the α-proton to C4' of pyridoxamine 5'-phosphate (PMP). The steady-state kinetics corresponds to the ping pong bi bi mechanism shown at the bottom of fig. 13-1. This mechanism allows L-aspartate to react with the internal aldimine, E=PLP in fig. 13-1, to produce an equivalent of oxaloacetate, with conversion of PLP to PMP at the active site (E.PMP), the free, covalently modified enzyme in the ping pong mechanism.

Modern Views on the Chemistry of Vulcanization Changes. II. Role of Hydrogen Sulfide

1947 ◽  
Vol 20 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Ralph F. Naylor
Keyword(s):  
Hydrogen Sulfide ◽  
Hydrogen Atom ◽  
Ultraviolet Light ◽  
Radical Reaction ◽  
Radical Type ◽  
Polar Reaction ◽  
Reaction Chain ◽  
Free Sulfur

Abstract 1. The normal addition of hydrogen sulfide to olefins is catalyzed by very small proportions of sulfur, but the rate of addition is too slow to provide a satisfactory basis for the hydrogen sulfide-actuated mechanism of vulcanization. 2. The main products of the sulfur-catalyzed (polar) reaction of hydrogen sulfide with polyisoprenes are substituted pentamethylene sulfides, derived by intramolecular normal addition of the initially formed monothiols. 3. The main products of the ultraviolet light-catalyzed (radical) reaction of hydrogen sulfide with polyisoprenes are monothiols and substituted pentamethylene sulfides, the latter derived by intramolecular abnormal addition. 4. The resemblance of the cyclic sulfides obtained by reaction of free sulfur with polyisoprenes to the products of polar hydrogen sulfide addition (as opposed to the products of the radical-type addition) supports the hypothesis that, in the sulfur-olefin reaction, the radical reaction chain is terminated by the capture of a hydrogen atom by an RS* radical, the thiol so formed adding intramolecularly in a polar reaction catalyzed by sulfur.

Catalysis by substituted iron phthalocyanines of crystal violet leucobase oxidation with dioxygen

2014 ◽  
Vol 18 (10n11) ◽  
pp. 1057-1062
Author(s):  
Tatiana M. Fedorova ◽  
Valentina M. Derkacheva ◽  
Eugene A. Lukyanets ◽  
Oleg L. Kaliya
Keyword(s):  
Induction Period ◽  
Crystal Violet ◽  
Catalytic Reaction ◽  
Oxidation Process ◽  
Radical Reaction ◽  
Acidic Form ◽  
Kinetics Of

The catalytic reaction of crystal violet leucobase oxidation by dioxygen in o-dichlorobenzene into corresponding dye was studied as a model of hydrocarbons C – H group oxidation. Substituted iron phthalocyanines in acidic form HPcFeX were used as the catalysts. It was shown that the oxidation process was accompanied in all cases by autocatalytic destruction of catalyst with induction period depending on concentrations of reactants. The kinetics of dye formation and catalyst degradation, as well as the effect of radical reaction inhibitors were studied. The nature of the process main stages was proposed.

scholarly journals Characterization of Biofilm Forming Marine Pseudoalteromonas spp

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Samia S. Abouelkheir ◽  
Eman A. Abdelghany ◽  
Hanan A. Ghozlan ◽  
Soraya A. Sabry
Keyword(s):  
Marine Environment ◽  
Crystal Violet ◽  
Marine Sponge ◽  
Marine Bacteria ◽  
Biofilm Formation ◽  
Test Tube ◽  
Rock Surface ◽  
Isolation And Characterization

Biofilm forming bacteria are omnipresent in the marine environment. Pseudoalteromonas is one of the largest within the γ-proteobacteria class, and a member of marine bacteria. Species of Pseudoalteromonas are generally found in association with marine eukaryotes. In this work, we present the isolation and characterization of two strains forming biofilm on rock surface and associated with marine sponge. They were identified using 16SrDNA as Pseudoalteromonas prydzensis alex, and Pseudoalteromonas sp. alex. They showed the highest titer in biofilm formation quantified using the test tube method using crystal violet.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

Atom-probe analysis of the solid-liquid interface

1995 ◽  
Vol 53 ◽  
pp. 676-677
Author(s):  
J.A. Panitz
Keyword(s):  
Molecular Level ◽  
Selective Adsorption ◽  
Electronic Devices ◽  
Atom Probe ◽  
Chemical Agent ◽  
Hostile Environment ◽  
Solid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Chemically Selective

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.

The Nature of Oxide Surfaces: Topographic and Electronic Structure

1993 ◽  
Vol 51 ◽  
pp. 966-967
Author(s):  
Dawn A. Bonnell ◽  
Yong Liang
Keyword(s):  
Transition Metal Oxides ◽  
Electronic Structures ◽  
Recent Progress ◽  
Spatial Localization ◽  
Level Of Detail ◽  
Scanning Tunneling ◽  
Oxide Surfaces ◽  
Tunneling Microscopy ◽  
Considerable Effort ◽  
Complete Understanding

Recent progress in the application of scanning tunneling microscopy (STM) and tunneling spectroscopy (STS) to oxide surfaces has allowed issues of image formation mechanism and spatial resolution limitations to be addressed. As the STM analyses of oxide surfaces continues, it is becoming clear that the geometric and electronic structures of these surfaces are intrinsically complex. Since STM requires conductivity, the oxides in question are transition metal oxides that accommodate aliovalent dopants or nonstoichiometry to produce mobile carriers. To date, considerable effort has been directed toward probing the structures and reactivities of ZnO polar and nonpolar surfaces, TiO2 (110) and (001) surfaces and the SrTiO3 (001) surface, with a view towards integrating these results with the vast amount of previous surface analysis (LEED and photoemission) to build a more complete understanding of these surfaces. However, the spatial localization of the STM/STS provides a level of detail that leads to conclusions somewhat different from those made earlier.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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