Extrinsic factor

Diurnal variation and seasonal variation are other intrinsic factors affecting chemical accumulation in both wild and cultivated plants. Depending on the plant, the accumulation of chemical constituents can occur at any time during the various stages of growth. In a majority of cases, maximum chemical accumulation occurs at the time of flowering, followed by a decline 

Besides the unintentional in-process adulteration of heavy metals, it is well established that Ayurvedic medicine and traditional Chinese medicine sometimes employ complex mixtures of plant, animal, and mineral substances, and it is not uncommon to find appreciable quantities of heavy metals such as lead, mercury, cadmium, arsenic, and gold in certain formulations (19,22,23). 

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In 1929, Castie (7) tied the work of Combe and Addison with that of Whipple, Miaot, and Murphy by ptoposiag that both an extrinsic factor and an intrinsic factor ate iavolved ia the coatrol of pernicious anemia. The extrinsic factor, from food, is vitamin 2- Th intrinsic factor is a specific B22-biading protein secreted by the stomach. This protein is requited for vitamin B 2 absorption. 

Vitamin B12 is special in as far as its absorption depends on the availability of several secretory proteins, the most important being the so-called intrinsic factor (IF). IF is produced by the parietal cells of the fundic mucosa in man and is secreted simultaneously with HC1. In the small intestine, vitamin B12 (extrinsic factor) binds to the alkali-stable gastric glycoprotein IF. The molecules form a complex that resists intestinal proteolysis. In the ileum, the IF-vitamin B 12-complex attaches to specific mucosal receptors of the microvilli as soon as the chymus reaches a neutral pH. Then either cobalamin alone or the complex as a whole enters the mucosal cell. 

Mixed asthma (caused by both intrinsic and extrinsic factors)... 

Extrinsic Factor PK Study Reports (diet, smoking, alcohol use, etc.)... 

LUDIKHUYZE L, RODRIGO L and HENDRICKSE M (2000) The activity of myrosinase from broccoli (Brassica oleracea L.cv. Italica) influence of intrinsic and extrinsic factors J Food Protect, 63 400-403. 

Major determinants of membrane fluidity may be grouped within two categories [53] (1) intrinsic determinants, i.e., those quantifying the membrane composition and phase behavior, and (2) extrinsic determinants, i.e., environmental factors (Table 1). In general, any manipulation that induces an increase in the molal volume of the lipids, e.g., increase in temperature or increase in the fraction of unsaturated acyl chains, will lead to an increase in membrane fluidity. In addition, several intrinsic and extrinsic factors presented in Table 1 determine the temperature at which the lipid molecules undergo a transition from the gel state to liquid crystalline state, a transition associated with a large increase in bilayer fluidity. 

Calof A.L. (1995). Intrinsic and extrinsic factors regulating vertebrate neurogenesis. Curr Opin Neurobiol 5, 19-27. 

It is quite clear from these data that intrinsic resistance to dislocation motion in these metals does not determine their indentation hardnesses. Internal friction measurements have yielded similar results. Therefore, extrinsic factors need to be considered. 

Steels and other structural transition-metal alloys are hardened by various extrinsic factors. The compositions and internal micro-structures of these materials are very complex. Therefore, simple descriptions and/or interpretations of their behaviors cannot be given, so they will not be discussed here. 

The most important of the extrinsic factors that affect the hardnesses of the transition metals are covalent chemical bonds scattered throughout their microstructures. These bonds are found between solute atoms and solvent atoms in alloys. Also, they lie within precipitates both internally and at precipitate interfaces with the matrix metal. In steel, for example, there are both carbon solutes and carbide precipitates. These effects are ubiquitous, but there... 

The crystal structure of NiAl is the CsCl, or (B2) structure. This is bcc cubic with Ni, or A1 in the center of the unit cell and Al, or Ni at the eight comers. The lattice parameter is 2.88 A, and this is also the Burgers displacement. The unit cell volume is 23.9 A3 and the heat of formation is AHf = -71.6kJ/mole. When a kink on a dislocation line moves forward one-half burgers displacement, = b/2 = 1.44 A, the compound must dissociate locally, so AHf might be the barrier to motion. To overcome this barrier, the applied stress must do an amount of work equal to the barrier energy. If x is the applied stress, the work it does is approximately xb3 so x = 8.2 GPa. Then, if the conventional ratio of hardness to yield stress is used (i.e., 2x3 = 6) the hardness should be about 50 GPa. But according to Weaver, Stevenson and Bradt (2003) it is 2.2 GPa. Therefore, it is concluded that the hardness of NiAl is not intrinsic. Rather it is determined by an extrinsic factor namely, deformation hardening. 

Clearly, the hardnesses of thermoplastic polymers are not intrinsic. They depend on various extrinsic factors. Only trends can be cited. For example, as the molecular weight in polyethylene materials increases, they become harder. And, as the molecular aromaticity increases, a polymeric material becomes harder. Thus, higher molecular weight anthracene is harder than napthalene and more aromatic Kevlar is harder than polymethacrylate. 

Therefore, other factors that have not yet been studied and are not easily quantifiable, such as the absorption properties of the C.-T. adduct at the surface of the metal powder and the solubility of the formed species should be important in determining the oxidation properties of C.-T. adducts towards metal powders. Furthermore, some extrinsic factors inherent to the experimental conditions, such as reaction temperature, reagent concentration, and nature of the solvent have been reported to affect the overall yield or the course of the reaction, and led to separation of different products in some cases.55 59 In any case, it appears that the simultaneous presence of the donor molecule and the di-/inter-halogen lowers the oxidation potentials of the metals, allowing their oxidation, dissolution, and complexation. 

Direct and indirect costs are compared public and private costs are estimated at 3.5-4 times those for EPA in 1981. Among the former is loss of innovation. While several studies of this factor have been made for the industry, their reliability is questioned, due in part to lack of sound data prior to 1976. No mention was made of economic trends affecting corporate expenditures for research and development, or of trends in the maturation of industrial chemistry itself. Other indirect costs, such as concentration of manufacture within the industry, may result from costs of compliance, especially for smaller manufacturers. These factors were not compared with extrinsic factors, such as shifts in feedstock supply and commodity manufacture from the United States to other countries. 

The forward and backward activation free energies and the corresponding rate constants thus depend on an extrinsic factor, the standard free energy of the reaction, AG° = E — E°, and an intrinsic factor, the standard activation free energy, that reflects the solvent and internal reorganization energy, Aq and A [equation (1.31)]. 

Whether or not chemical reactivity hazards are present is a function not only of each chemical s reactivity (by itself and in combination), but also of various extrinsic factors i.e., factors that are not intrinsic properties of the chemicals being handled. As the design for a facility progresses, decisions will be made regarding these factors that will affect the magnitude of the chemical reactivity hazards and the potential consequences if their control is lost. A partial list of extrinsic factors includes ... 

Hazard(s) identification, 78-84 chemical structure and bonds, 80,82 compatibility, 82-83, 84 diversity of reactions, 79-80,81 extrinsic factors evaluation, 83 heat of reaction, 79 literature surveys, 78... 

A performance-based system-rather than a list of reactive chemicals -is suggested as another alternative for extending regulatory coverage of reactive hazards. Such a system would consider the risk of reactive chemicals, site-specific (extrinsic) factors such as siting and proximity, and conditions that create potentially reactive situations. Objective criteria such as the North American Industry Classification System (NAICS) codes, accident history, or number of employees could be used to establish coverage. 

Pavia H, Brock E (2000) Extrinsic factors influencing phlorotannin production in the brown seaweed Ascophyllum nodosum. Mar Ecol Prog Ser 193 285-294 Pavia H, Toth GB (2000a) Inducible chemical resistance to herbivory in the brown seaweed Ascophyllum nodosum. Ecology 81 3212-3225... 

Waterman PG, Mole S (1989) Extrinsic factors influencing production of secondary metabolites in plants. In Bernays EA (ed) Insect-plant interactions. CRC, Boca Raton, FL, pp 107-164 Weidner K, Lages BG, da Gama BAP, Molis M, Wahl M, Pereira RC (2004) Effect of mesograz-ers and nutrient levels on induction of defenses in several Brazilian macroalgae. Mar Ecol Prog Ser 283 113-125... 

D2. Daynes, R. A., and Araneo, B. A., Programming of lymphocyte response to activation extrinsic factors. Chem. Immunol. 54, 21-43 (1992). 

Castle then showed (1929) that beef muscle was as effective as liver in preventing pernicious anemia, provided it was administered with normal gastric juice. He therefore concluded two factors were involved—an extrinsic one which was a component in liver or muscle and an intrinsic factor which was secreted by the stomach. Major efforts were therefore directed at identifying the extrinsic factor in liver or other meats. 

Preload and afterload are extrinsic factors that influence contractility whereas intrinsic factors include autonomic nervous system activity and catecholamine effects. 

Foreign clinical results are acceptable except in areas where there are immunological and ethnic differences between Japanese and foreigners. The ethnic factors are divided into two components intrinsic factors such as racial factors and physiological differences and extrinsic factors, which include cultural and environmental issues. In these cases, the MHLW may require that some bridging comparative clinical trials be performed with dose ranging protocols. This will enable absorption, distribution, metabolism, and excretion studies to be carried out on Japanese individuals and provide better dosage and indication for the Japanese people. The MHLW also requires that application be accompanied by one year of real-time stability data and that sterility test results be included. 

Cobalamine can only be resorbed in the small intestine when the gastric mucosa secretes what is known as intrinsic factor—a glycoprotein that binds cobalamine (the extrinsic factor) and thereby protects it from degradation. In the blood, the vitamin is bound to a special protein known as trans-cobalamin. The liver is able to store vitamin Bi2 in amounts suf cient to last for several months. Vitamin B12 deficiency is usually due to an absence of intrinsic factor and the resulting resorption disturbance. This leads to a disturbance in blood formation known as pernicious anemia. 

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