Biological aspects

Biological Aspects.—The lowest excited triplet states of all-rran.s- -carotene produced by pulse radiolysis has been studied by time-resolved resonance Raman spectroscopy.Six transient Raman bands at 965, 1009, 1125, 1188, 1236, and 1496cm were observed and assigned to the triplet state of ) -carotene. The authors conclude that the molecule may be substantially twisted, presumably at the 15,15 band in the triplet state. Further work has also been carried out by the same workers on the triplet state of all-rran -retinal. The results indicate increased 7r-electron delocalization in the triplet state and propose that the relaxed excited triplet-state exists in either sAX-trans or 9-cis conformation. Das and Becker have also employed pulse radiolysis and laser flash photolysis to study several photophysical properties of the triplet states of the series of polyenals (29)—(33) related to retinal (31) as homologues (Table 35). Results are presented 

All-trans- polyenal Solvent Band max (nm ) Extinction coeff. at hand max (M cm X 10 ) Triplet state decay constant ps y K 

The naphthalene-sensitized formation of triplet-excited chlorophyll a (chi a) and d -trans j3-carotene has been investigated by pulse radiolysis. Rate constants for transfer of triplet energy from naphthalene to chi a and d -tram fi-carotene in benzene at 25°C are 3.6 + 0.6 x 10 M s and 10.7 1.2 X 10 M s , respectively. Rate constants for triplet-triplet annihilation are 1.4 0.3 X 10 M s for chi fl and 3.6 0.4 x 10 M s for aW-trans jff-carotene. 

Much more is known about the interaction of cells with laminin. A high-affinity (Ad = 1 x 10 9 to 4 x 10-9) receptor for laminin has been found on many cells including myoblasts, tumor cells, and macrophages (Lesot et al., 1983 Rao et al., 1983 Malinoff and Wicha, 1983). The laminin receptor (Mr 67K) is solubilized by detergent and has all the characteristics of an integral membrane protein. A partial amino acid sequence of the receptor has been deduced from the nucleotide sequence of cDNA clones. These show a possible transmembrane sequence and suggest that this receptor has substantial cytoplasmic and extracellular domains (Wewer et al., 1986). 

Engvall, E., Krusius, T., Wewer, U., and Ruoslahti, E. (1983). Arch. Biochem. Biophys. 222, 649-656. 

Kefalides, N. A., ed. (1978). Biology and Chemistry of Basement Membranes. Academic Press, New York. 

Schone, F. H., and Timpl, R., eds. (1982). New Trends in Basement Membrane Research. Raven, New York. 

The adverse pathological effects of dental silicate cement have been known since Kulka (191 la,b). Since then many workers have observed that this cement causes significant pulpal inflammation (McComb, 1982). 

Manley (1936, 1943) reported that major histological changes occurred in the pulp 24 hours after placing a silicate restoration, a finding confirmed by other workers (Zander, 1946 Brannstrom Nyborg, 1960 Stanley, Swerdlow Buonocore, 1967 Qvist, 1975). The silicate cement also inflames the gingiva (gum tissues) (Larato, 1971 Trivedi Talim, 1973) and demineralizes both dentine and enamel (Grieve, 1974). 

At one time, irritation of the pulp was entirely attributed to the acidity 

Watts (1979), while agreeing that bacterial contamination plays an important role in causing irritation to tissues, showed that a silicate cement even under germ-free conditions produced tissue damage. Of course, the acidic dental silicate cement does not possess the antiseptic action of the alkaline cements. 

Cell culture tests show that dental silicate cement is strongly cytotoxic - that is it severely damages cells - even after set (Spangberg et al., 1973). This effect has been attributed to the hydrogen and fluoride ions present (Helgeland Leirskar, 1972, 1973 Tyas, 1979). 

The epoxide of vitamin K is involved in the regeneration of the anticoagulant vitamin (a naphthoquinone) from the active hydroquinone form (81JA5939). 

The mechanisms of formation of oxiranes by biological systems (which are relevant to carcinogenesis — see the penultimate paragraph) are the subject of continuing interest 81JA6744. 81JA7371). 

Besides the thorough biochemical investigation of a sample for its elemental composition or the fractions of the major components (carbohydrates, proteins, lipids) another way to derive biomass is to assume a proportionality between the nitrogen content of a sample and the amount of living matter. The chemical analysis of nitrogen which can be performed with a number of methods and an appropriate conversion factor (see above) then render the wanted amount of biomass. 

Combustion experiments are only meaningful when they proceed in an explo-sion-like manner to a final, thermodynamically well-defined state. The main question for biological matter concerns the state of water in the bomb liquid or vapour. In the case of vapour, the heat of evaporation is lost from the combustion energy, One talks about the gross heating value or the high heat value (HHV) when all water (moisture + water formed by combustion) is in liquid form, otherwise about the low heat value (LHV), Depending on the amount of water these two values may differ considerably (see e.g. [36] and Chapter fVood in this volume). 

At the end of this section an essential caveat should be kept in mind. Caloric values less than 17.6 kJ/g afdw should be considered with suspicion. Carbohydrates bum with the lowest energy content of 17.6 kJ/g, proteins and lipids with higher values (see Table 1). Combustion heats lower than 17.6 kJ/g afdw may be due to a wrong determination of the ash fraction or to contributions of inorganic reactions during burning (see e.g. [37]). 

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Table 2. Biological Aspects of Plasma Coagulation Factors...

S. Langerd, Environmental and Biological Aspects of Chromium, Elsevier, Amsterdam, The Netherlands, 1983. 

OXIRANES APPLICATIONS, BIOLOGICAL ASPECTS, OCCURRENCE 5.05.5.1 Applications... 

The special topics discussed are (i) the biological aspects of heterocyclic compounds, i.e. their biosynthesis, toxicity, metabolism, role in biochemical pathways, and their uses as pharmaceuticals, agrochemicals and veterinary products (ii) the use of heterocyclic compounds in polymers, dyestuffs and pigments, photographic chemicals, semiconductors and additives of various kinds and (iii) the use of heterocyclic compounds as intermediates in the synthesis of non-heterocyclic compounds. 

Santi, D V, Pogolotti, A L Jr, Newman, E M, Wataya, T In Biomedia nal Aspects of Fluorine Chemistry, Filler, R, Kobayashi, Y, Eds, Kodan-shaLtd Tokyo, and Elsevier Biomedical Amsterdam, 1982, pp 123-142 Withers, S G, Street, I P,Percival, M D a Fluonnated Carbohydrates Chemical and Biological Aspects, Taylor, N F, Ed, ACS Symposium Senes 374, Amencan Chemical Society Washmgton, DC, 1988, pp 59 77... 

Synthetic, structural, reactive, and biological aspects of novel tetraazabicyclooc-tanes 95F379. 

Robben JH, Knoers NV, Deen PM (2006) Cell biological aspects of the vasopressin 1ype-2 receptor and aquaporin 2 water channel in nephrogenic diabetes insipidus. Am J Physiol Renal Physiol 291 F257-F270... 

Poignard P, Saphire EO, Parren PW, Burton DR (2001) gpl20 Biologic aspects of structural features. Annu Rev Immunol 19 253-274... 

This report covers the synthetic and structural aspects of the subiect with discussion of the biological aspects included where relevant It covers the 1970 literature 2S4pp 16 00 (Still eveilsbie Vo 1 14 50 Vof 2 6 00)... 

Lipids may be defined as a large group of molecules with a substantial portion of aliphatic or aromatic hydrocarbon. Included are molecules with diverse chemical characteristics, such as the hydrocarbons, soaps, detergents, acylglycerols, steroids, phospholipids, sphin-golipids, and fat-soluble vitamins, and, subsequently, with diverse physical behavior. One of the most important characteristics of lipids from a biological aspect is their behavior in aqueous environments, as all cells exist in an aqueous milieu. In this respect, the lipids range from almost total insolubility to nearly complete solubility. 

Leenheer, J.A., Malcolm, R.L., and White, W.R., Physical, Chemical and Biological Aspects of Subsurface Organic Waste Injection near Wilmington, North Carolina, U.S. Geological Survey... 

The increased knowledge of the role of zinc in biological systems has allowed study of the coordination chemistry of small-molecule mimics and the enzymes themselves.964 A number of texts deal with biological aspects of zinc and zinc enzymes.965- 68... 

Photophysical, Analytical and Biological Aspects Volume Editors P. Hanninen and H. Harma Vol. 7... 

Handbook of Drug and Alcohol Abuse. The Biological Aspects (pp. 117-131). Oxford University Press, Oxford, UK. 

Gold MS (1992). Marihuana and hashish. In G Winger, FG Hoffmann and JH Woods (eds), A Handbook of Drug and Alcohol Abuse. The Biological Aspects (pp. 117-131). Oxford University Press, Oxford, UK. 

Volume 336. Microbial Growth in Biofilms (Part A Developmental and Molecular Biological Aspects)... 

The diazines pyridazine, pyrimidine, pyrazine, and their benzo derivatives cinnoline, phthalazine, quinazoline, quinoxaline, and phenazine once again played a central role in many investigations. Progress was made on the syntheses and reactions of these heterocycles, and their use as intermediates toward broader goals. Some studies relied on solid-phase, microwave irradiation, or metal-assisted synthetic approaches, while others focused attention more on the X-ray, computational, spectroscopic, and natural product and other biological aspects of these heterocycles. Reports with a common flavor have been grouped together whenever possible. 

Beninson, D., Vander Elst, E. and Cancio, D. (1966). Biological aspects in the disposal of fission products in surface waters, page 337 in Disposal of Radioactive Wastes into Seas, Oceans and Surface Waters, IAEA Publication No. STI/PUB/126 (International Atomic Energy Agency, Vienna). 

SC-40 Biological Aspects of Radiation Protection Criteria SC-41 Radiation Resulting from Nuclear Power Generation SC-42 Industrial Applications of X Rays and Sealed Sources SC-44 Radiation Associated with Medical Examinations SC-45 Radiation Received by Radiation Employees SC-46 Operational Radiation Safety... 

Zaki, F.N. and M.A. Gesraha. 1987. Evaluation of zertel and diflubenzuron on biological aspects of the egg parasitoid, Trichogramma evanescens Westw. and the aphid lion Chrysoperla camea Steph. Jour. Appl. Entomol. 104 63-69. 

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