Chemical fixation

Despite the drawbacks of chemical-fixation based procedures [21,24], most of our current knowledge on biological ultrastnicture relies on this approach. In contrast to cryopreparative procedures, chemical fixation does not require special skills and instrumentation. 

The chemical fixation of N2 to NH3 under less extreme conditions than those used industrially i.s a continuing area of active research and considerable progress has been made in elucidating mechanisms involving N2 coordinated to Mo. W, V and other cenlres. - - ... 

Transporting the dust to an offsite processor for thermal treatment and removal of zinc, chemical fixation, glassification, or fertilizer manufacture... 

Chemical fixation for transmission electron microscopy prepares cells for the preservation of damage due to subsequent washing with aqueous solvents, dehydration with organic solvents such as ethanol or acetone, embedding in plastic resins, polymerization of the resins by heat, exothermic catalysts, or ultraviolet radiation, and imaging with high-energy electron beams in an electron microscope. 

Somljo It all depends on the fixation method. We use osmium ferricyanide to selectively infiltrate the SR. If we use intermediate high-voltage electron microscopy, we can look at thicker specimens, and this technique provides more extensive views than obtained from the usual thin sections. This is the same information we get when we infiltrate the SR with Fluo-3. These pictures are pretty reliable. Furthermore, if you want to confirm without chemical fixation, methods such as rapid freezing are available. All these techniques give the same pictures, which vary according to the smooth muscle type. 

As mentioned, chemical fixation of plant cells has been reviewed many times (15-20) and the reader is referred to these citations for a variety of fixation procedures for preserving plant cells and tissues. One of the most recent references regarding the topic is that of Hopwood and Milne (21). Table 1 presents their recommendations regarding fixation of plant cells and tissues for electron microscopy. 

Recently, microwave fixation (21) has been utilized as an alternative to chemical fixation as another effort to circumvent artefacts induced by chemical fixation. During microwave fixation, heat is delivered in a controlled manner uniformly throughout the tissue, i.e., thin slices. The penetration of microwaves into the tissue is limited to approx 2 cm from the surface. 

Air drying, usually with subsequent chemical post-fixation, is applicable for cell smears, cytospins and cryosections. Snap freezing (usually in liquid nitrogen) is routinely employed for tissue probes for subsequent cryosectioning. Chemical fixation is commonly carried out in aldehydes (e.g. formaldehyde) for tissue probes and cultured cell monolayers, and in acetone or alcohols (methanol or ethanol) for cryosections and cell preparations. 

J.R. Comer Chemical Fixation and Solidification of Hazardous wastes, Van Nostrand-Reinhold, New york, 1990. 

Pizzi, A. (1990). Extended durability by the chemical fixation of unsaturated alkyd finishes to wood. Holzforschung und Holzverwertung, 42(6), 107-109. 

The localization of proteins and carbohydrates within cells and tissues with specific antibodies has long been proven to be a valuable technique. Immuno-localization procedures allow one to detect not only well-characterized cellular structures but also provide information about newly characterized proteins and carbohydrates. This chapter will review some of the advantages and drawbacks of common chemical fixation and permeabilization methods used for immuno-localization at the level of light microscopy. 

It is entirely possible that surface staining cannot be accomplished before fixation. Some antibody-antigen complexes cannot withstand chemical fixation and/or permeabilization. An empirical evaluation must be made. In this example, cells are first stained with a monoclonal antibody against a cell-surface receptor, fixed with ethanol, and then the DNA is stained with propidium iodide. The cells are analyzed for two-color fluorescence, the green of the fluorescein-labeled surface marker and the red of the labeled DNA intercalator. This approach works for antibody-antigens that are unaffected by fixation. 

Potential treatment and disposal methods for drilling fluids include (1) fluid ejection, (2) pit and solids encapsulation, (3) injection into safe formations, (4) removal to disposal sites off location, (5) incineration, (6) microorganism processing, and (7) distillation, liquid extraction, and chemical fixation [13]. 

C. Bosch gave him, as his assistant, the assignment of working out a technical method for the chemical fixation of elementary nitrogen in the... 

Simultaneously, a general study was made on the chemical fixation of elementary nitrogen to many other chemical elements including the reaction between nitrogen and hydrogen, and the optimal conditions were investigated for the formation of many nitrides, including ammonia. 

A technical exploitation of these experiments appeared unattractive, until 1909. Other methods of the chemical fixation of nitrogen, particularly the electric arc process for the formation of nitrous oxides (18) and the calcium cyanamide process (19) appeared far superior at that time. 

T0705 Separation and Recovery Systems, Inc., SAREX Chemical Fixation Process... 

T0700 Seaview Thermal Systems, High-Temperature Thermal Distillation T0701 Seiler Pollution Control Systems, High-Temperature Vitrification System T0705 Separation and Recovery Systems, Inc., SAREX Chemical Fixation Process... 

The CFX MiniFix technology is categorized as a chemical fixation/stabilization process. The patented process, enhanced by additional proprietary developments, stabilizes mobile constituents within a waste matrix by ntiUzing the chemical reactions between complex silicates. The reactions solidify and stabilize the wastes into a claylike product that is suitable for either on-site or landfill disposal. The matrix-forming chemistry is assisted as needed by reaction-promoting additives. 

The Chemfix process is categorized as a chemical fixation/stabilization technology. This patented process, enhanced with proprietary developments, stabilizes mobile constituents within a waste matrix by chemical and physical means. 

MARCOR Environmental, Inc. s, Advanced Chemical Treatment (ACT) is a chemical fixation method for the treatment of contaminated soils, sediments, and sludges. The vendor claims that by mixing contaminated materials with ACT reagents, the contaminants are oxidized, catalyzed, and mineralized. Target contaminants may include coal tar wastes polycyclic aromatic hydrocarbons (PAHs) benzene, toluene, ethylbenzene, and xylenes (BTEX) chromium copper and lead. 

The Metals Treatment Technology (MTT ) is a chemical fixation process that stabilizes heavy metals in soils, slndges, and sediments. The process nses bnffered phosphate componnds to convert heavy metals into insolnble metallic salts. The process chemicals may be applied to contaminated media in situ or ex situ. 

Reduces leachability through the chemical fixation of the organic component of the waste. 

The ARCHON in situ mixer unit consists of a hydraulically powered grinding/mixing head, typically attached to a long-reach backhoe or to a wide-track bulldozer for extensive wet areas. The process is designed to feed a continuous supply of chemical fixation and stabilization additives, which are added to the waste during the grinding/mixing operation. 

Matsuda, Akutsu, et al. [141] carried out chemical fixation of GRGDSP onto a poly(vinyl alcohol) film which had been activated by carbonyl diimidazol in dimethylformamide. For comparison, fibronectin was also immobilized on a poly(vinyl alcohol) film by the same technique. Matsuda et al. found that bovine endothelial cells (ECs) adhered well to the peptide- and fibronectin-immobilized film furthermore, after a three-day incubation, aggregated ECs floated on nontreated PVA film, while the peptide-immobilized surface greatly enhanced cell spreading and growth, which surpassed that on fibronectin-bound PVA. 

M. M. Hal man n, Chemical Fixation of Carbon Dioxide Methods for Recycling C02 into Useful Products, CRC Press, Boca Raton, FL, 1993. 

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