Irradiation chemical method

Riboflavin can be assayed by chemical, en2ymatic, and microbiological methods. The most commonly used chemical method is fluorometry, which involves the measurement of intense yeUow-green fluorescence with a maximum at 565 nm in neutral aqueous solutions. The fluorometric deterrninations of flavins can be carried out by measuring the intensity of either the natural fluorescence of flavins or the fluorescence of lumiflavin formed by the irradiation of flavin in alkaline solution (68). The later development of a laser—fluorescence technique has extended the limits of detection for riboflavin by two orders of magnitude (69,70). 

Viruses and bacteria may be eliminated by chemical methods or by irradiation, and organic poisons may also be controlled. Inorganic matter must be removed by other means. 

This paper describes an irradiation curing method which improves the mechanical, chemical, and thermal properties of multilayered flexible materials, increases the bond strength among the adhesively bonded layers, and provides flexible packages that can withstand the thermo-... 

Intensive technologies are derived from the processes used for the treatment of potable water. Chemical methods include chlorination, peracetic acid, ozonation. Ultra-violet irradiation is becoming a popular photo-biochemical process. Membrane filtration processes, particularly the combination microfiltration/ultrafiltra-tion are rapidly developing (Fig. 3). Membrane bioreactors, a relatively new technology, look very promising as they combine the oxidation of the organic matter with microbial decontamination. Each intensive technique is used alone or in combination with another intensive technique or an extensive one. Extensive... 

Glenn Theodore Seaborg (1912-1999), together with Ralph A. James and Albert Ghiorso J ( 1915). Irradiation of a plutonium-239 sample with alpha particles and enrichment of 242Cu by chemical methods. 

In a review by Gonsalves el al. (2000), techniques for the fabrication of nano-structured materials are outlined. Synthesis from corresponding organo-metal precursors of nano-structured metals (Fe, Co, Ni) and alloys (Fe-Co, Pt-Pd, and special steels) are discussed and various methods considered such as thermal decomposition, ultrasonic irradiation, chemical vapour deposition, laser pyrolysis and reduction. 

One of the common chemical methods for determining carbonyl compounds consists of converting them into hydrazones [7], This has been used for (1) oxycellulose [28], (2) nylon-6 and nylon-6,6 [29], (3) dehydrogenated poly (vinyl chloride) [30], (4) in irradiated polyethylene films [31], and (5) grafted polyethylene glycol [32],... 

Many investigators are seeking further improvements in the handling of fresh produce. Among methods receiving much attention are the use of postharvest chemicals, retardants of senescence, thermal treatment, controlled atmospheres, new packaging techniques, better temperature control in storage and transit, and irradiation. One method may work well with one fruit or a particular variety of fruit but not with another fruit. 

The study described here demonstrates that ESCA provides information regarding the chemical nature of the surface of an unperturbed sample which would be difficult to acquire by other methods. A major weakness of ESCA, the necessity of exposing the sample to vacuum, together with its attendant problem of sample volatilization, can also be one of its strengths. The volatility of some nitrogenous species in atmospheric aerosol particles can be used to provide strong evidence for chemical identity of ionic compounds (e.g., ammonium nitrate) rather than simply ionic identities as provided by wet chemical methods. This volatility is accelerated by x-ray irradiation, so that similar results could be achieved only by extended vacuum exposure alone if another analytical technique were used. Also, with ESCA, volatile losses can be conveniently monitored since the sample remains in the spectrometer throughout the process. 

Inactivation of mycotoxins. When removal or elimination of mycotoxins is not possible, mycotoxins can be inactivated by (a) physical methods such as thermal inactivation, photochemical or gamma irradiation (b) chemical methods such as treatment of commodities with acids, alkalis, aldehydes, oxidizing agents, and gases like chlorine, sulfur dioxide, ozone and ammonia [201] and (c) biological methods such as fermentations or enzymatic digestions that cause the breakdown of mycotoxins [202]. 

Accurate measurement of free-radical and molecular-product yields is important in radiation-chemistry studies on aqueous solutions, for these measurements enable quantitative predictions to be made regarding the extent of chemical changes during irradiations, and lead to an understanding of reaction mechanisms. Therefore, recent research has been directed toward the measurement of these yields, which are generally expressed as G values. An excellent account of the chemical methods used for determining G values... 

In addition to chemical methods variety of physical methods has been employed for the synthesis of AuNPs. UV irradiation is used to improve the quality of the AuNPs when it is used in synergy with micelles or seeds [32,33], Near-IR laser irradiation provokes an enormous size growth of thiol-stabilized AuNPs [34], The presence of an ultrasonic field (200 kHz) allowed the control of the rate of AuC14" reduction in an aqueous solution containing only a small amount of 2-propanol and the sizes of the formed AuNPs are controlled by varying the parameters such as the temperature of the solution, the intensity of the ultrasound, and the positioning of the reactor [35,36], Sonochemistry was also used for the synthesis of AuNPs within the pores of silica and for the synthesis of Au/Pd bimetallic particles [37,38], Radiolysis has been used to control the size of AuNPs [39], Laser photolysis has been used to form AuNPs in block copolymer micelles. Laser ablation is another technique of AuNP synthesis that has been used under various conditions whereby size control can be induced by the laser [40,41],... 

The subcellular distribution of phytochrome has been investigated with several methods (1) irradiation with a microbeam and polarized light, (2) immunocyto-chemical methods, and (3) cell fractionation. 

With a single-line source, two photochemically active components can be separated in solution by irradiation and subsequent reaction of one of the components. This technique has been applied to the separation of the transition metals cobalt and iron (10) and of europium from the other lanthanides (H). Although no separation of this type has been reported for the actinides, there is nothing in principle that prevents it. This method could prove particularly useful in separating actinides from lanthanides, where thermal chemical methods are particularly difficult. 

In the case of irradiated semiconductor suspensions, the monoacid is formed in a one-hole transfer reaction as given by the lower path in the reaction scheme. This reaction is of great interest because the monoacid described here is difficult to synthesize by ordinary chemical methods. Many other reactions have been investigated [118]. 

Solid-state amorphization can be induced through a variety of methods including irradiation, chemical reactions, mechanical-deformation techniques, pressure application, etc., as discussed above. As such, a crystalline phase can be driven into a disordered amorphous state as long as the kinetic constraints inhibiting stable phase formation can be maintained. 

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