Stem morphology

Deficiency. Macrocytic anemia, megaloblastic anemia, and neurological symptoms characterize vitamin B 2 deficiency. Alterations in hematopoiesis occur because of the high requirement for vitamin B 2 for normal DNA repHcation necessary to sustain the rapid turnover of the erythrocytes. Abnormal DNA repHcation secondary to vitamin B 2 deficiency produces a defect in the nuclear maturational process of committed hematopoietic stem cells. As a result, the erythrocytes are either morphologically abnormal or die during development. 

In hardwoods, morphological structural elements in longitudinal series comprise the segmented structure termed vessel . Vessels, which are exposed in transverse section, constitute about 10-46% of the stem volume in deciduous hardwoods and are cells of relatively large diameters (50-300 p.m). Vessels have in short the appearance of open vertical tubes within the wood structure because their end walls have partially dissolved. By comparison, the hardwood vessel diameter can be as much a 10 times the diameter of a softwood fiber. 

Deposit morphology is very important in determining the origins of mineral deposition. The analysis of the deposit may reflect a chain of cause-and-effect problems, and these problems may stem from any of several points within the steam-cycle system. 

The primary industries are pulp and paper, lumber, electronics, and tourism. The basin supports extensive wildlife and fish habitat. Precipitation varies from 100 cm at the basin floor to more than 300 cm in the Cascade Range and summers are dry and warm with winters cloudy and wet. Daily average temperatures in the basin range from 1.7 C in winter to 28°C in summer. A cross-sectional profile of the basin is shown in Figure 2A. Figure 2B identifies specific morphological reaches of the main stem Willamette River. 

Interest in chemical variation in Phytolacca dodecandra L Hert. stems from its potentially important biologically active constituents, perhaps the most significant of which is the mollnscicidal componnd lemmatoxin. Attempts to measure variation within this taxon, which occnrs widely on the African continent, have involved a stndy of morphological featnres (Adams et al., 1989) and the comparative chemical work to be described here (Adams et al., 1990). This more recent study involved analysis of nonpolar constitnents from three populations from Ethiopia, and one... 

Preliminaries. The combustion of suspended dusts and powders is quite complex and only imperfectly understood. The complexity stems from both fundamental and practical considerations. On the fundamental side, the ignition of suspensions of finely divided solids is influenced by hard-to-quantify factors such as the time-varying concentration of solids, the chemical activity and morphology of the particulate, and the degree of confinement provided by the vessel. On the practical side, industrial conditions are seldom sufficiently well-controlled or characterized to justify application of existing theoretical models. For all the above reasons, this chapter can provide only a very abbreviated coverage of ignition basics. The reader is referred to other sources for in-depth treatment of dust and powder explosions (Bodurtha, 1980 Bartknecht, 1981 Bartknecht, 1987). 

Buzanska, L., Stachowiak, E., Stachowiak, M. and Domanska-Janik, K. Neural stem cell line derived from human umbilical cord blood - morphological and functional properties. J. Neurochem. 85(Suppl. 2) 33, 2003. 

Slow-channel syndrome. Abnormally long-lived openings of mutant AChR channels result in prolonged endplate currents and potentials, which in turn elicit one or more repetitive muscle action potentials of lower amplitude that decrement. The morphologic consequences stem from prolonged activation of the AChR channel that causes cationic overload of the postsynaptic region - the endplate myopathy - with Ca2+ accumulation, destruction of the junctional folds, nuclear apoptosis, and vacuolar degeneration of the terminal. Some slow-channel mutations in the transmembrane domain of the AChR render the channel leaky by stabilization of the open state, which is populated even in the absence of ACh. Curiously, some slow-channel mutants can be opened by choline even at the concentrations that are normally present in serum. Quinidine, an open-channel blocker of the AchR, is used for therapy. 

A compilation of structure-function relationships for plant cells is depicted in Table 2 while Table 3 categorizes their locations within plant tissues. A color atlas of plant structure has been published by Bowles (102). The reader is referred to Esau (103), Fahn (105), Fosket (108), Maseuth (106), Moore and Clark (109), Steeves and Sussex (104), and Raven et al. (107) for in-depth discussions of both the morphology and physiology of stems, roots, leaves, and flowers, i. e., plant organs. Certain of these volumes consider the structural differences between monocot and dicot roots and stems. 

The molecular characterization of a polymeric material is a crucial step in elucidating the relationship between its properties (e.g., mechanical, thermal), its chemical structure, and its morphology. As a matter of fact, the development of a new product stems invariably from a good knowledge of the above relationships. Characterization of polymers is often a difficult task because polymers display a variety of architectures, including linear, cyclic, and branched chains, dendrimers, and star polymers with different numbers of arms. 

Figure 2.1. Development of blood cells. The development of blood cells occurs in the bone marrow. All cells arise from the differentiation of pluripotent or multipotent stem cells, which have the capacity for self-renewal, or else can divide into more mature cells types. The morphological features of the mature blood cell types is shown.

Chemically platinized platinum with the roughness factor ISO was used for the same experiment. The resTilt is shown in Fig. 2-43. The oxidation cmrent for eoCOad forms a small peak rather than just a shoulder. Since the roughness factors are almost same for both chemically and electrochemically platinized platinum electrodes, the difference probably stems from the morphology of the platinum. 

The reason that the full coverage could not be achieved is considered that some site are not accessible by CO. It is not known, however, whether this stems from the morphology of the platinum or an effect of Nafion as a surface modifier. 

Proton conductivities of 0.1 S cm at high excess water contents in current PEMs stem from the concerted effect of a high concentration of free protons, high liquid-like proton mobility, and a well-connected cluster network of hydrated pathways. i i i i Correspondingly, the detrimental effects of membrane dehydration are multifold. It triggers morphological transitions that have been studied recently in experiment and theory.2 .i29.i ,i62 water contents below the percolation threshold, the well-hydrated pathways cease to span the complete sample, and poorly hydrated channels control the overall transports ll Moreover, the structure of water and the molecular mechanisms of proton transport change at low water contents. 

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