Microscopic examination, growth

Measurements of overall reaction rates (of product formation or of reactant consumption) do not necessarily provide sufficient information to describe completely and unambiguously the kinetics of the constituent steps of a composite rate process. A nucleation and growth reaction, for example, is composed of the interlinked but distinct and different changes which lead to the initial generation and to the subsequent advance of the reaction interface. Quantitative kinetic analysis of yield—time data does not always lead to a unique reaction model but, in favourable systems, the rate parameters, considered with reference to quantitative microscopic measurements, can be identified with specific nucleation and growth steps. Microscopic examinations provide positive evidence for interpretation of shapes of fractional decomposition (a)—time curves. In reactions of solids, it is often convenient to consider separately the geometry of interface development and the chemical changes which occur within that zone of locally enhanced reactivity. 

Microscopic examination of the heart revealed edematous separation of myofibrils that had resulted in compression thinning and fragmentation of myofibres. Myofibre outlines were less distinct, and there was loss of acidophilic staining. Mitotic figures were rare, indicating that growth of the cardiac tissue was suppressed. The incidence of cardiac lesions is given (Table VI). 

Red slime deposits, which appeared to be biological in origin, were observed in one disassembled permeator. A microscopic examination of the slime revealed a heavy growth of a... 

As mentioned above we obtained most of the poison for our chemical and biological work from the Alaska butter clam. However our search for a dinoflagellate or any other poisonous organism in the water as a source of the poison in the clams was never definitely accomplished. In 1948, and in some years following, along with a survey for toxic butter clams in Southeastern Alaska by the staff at the Fishery Products Research Laboratory at Ketchikan, 1 collected plankton in areas where the clams were found to be toxic. Mouse assays of the plankton showed no toxicity. Microscopic examination of the water in these areas showed heavy growth of microscopic plankton but little or no evidence of... 

Some glass bottles, e.g. Roux bottles, are manufactured especially for growth of cells in culture and these have the advantage of improved optical qualities allowing easier microscopic examination of the growing cells. Some of the larger bottles are known by the name of the person who introduced them. 

The topographical studies of the oxide surface with the aid of optical and electron microscopes have shown the necessity for understanding the several types of oxidation which take dace on any one face. The nature of these processes, such as incubation and growth of nuclei of several types and the growth of the base film, seem to vary with die face exposed, as well as with other factors. The optical and electron microscopic examinations of oxide surfaces have shown clearly the limitations of rate or epitaxial studies alone for fully elucidating the oxidation process. 

McCrone (1957, 1965) has also given detailed descriptions of the microscopic examinations and phenomena that can be used to distinguish polymorphism from other phenomena that sometimes have been mistakenly labelled as pseudopolymorphism mesomorphism (i.e. liquid crystals), grain growth (boundary migration and recrystallization), and lattice strain. 

Cells are plated at the desired density, either on sterile glass cover-slips for microscopic examination, or directly into multiwell plates (prepare each point at least in tripUcate) for population analysis by ELISA. After treatment of the cells with the desired growth agents, BrdU is added, following the same criteria already discussed for thymidine labeling (short pulse, or long term). Cells are then washed free of residual BrdU by rinsing with PBS, and fixed in ethanol. Fixed cells can be stored at 4°C for further analysis. BrdU... 

Crystal growth of an industrially manufactured salicylic acid (9) powder (60 jt/m stated particle size) was demonstrated. A microscopic examination about eight months after its preparation showed a maximum particle size of 200-500 fjm. About one year later, examination showed further crystal growth, particle size now was 500-800 pm. A further examination after eight months showed no further particle size growth. Particle size growth of salicylic acid occurred even in the dry powder state and not only in ointments. 

Kinetics of nucleation may be studied by microscopic examinations of surfaces from which numbers of growth nuclei/unit area (N) are counted after known reaction times. Photographs of the surface may be taken at appropriate intervals and used to obtain the quantitative information. The nucleation law is sometimes also inferred from the overall kinetic behaviour. Precise fits to rate laws (including nucleation) require large numbers of accurate observations to enable reliable statistical analyses of the data to be made and it is frequently difficult to obtain sufficient numbers of reliable (N,t) values. The rate equations in Table 3.1. represent, to an acceptable approximation, all types of behaviour that can realistically be expected [10]. 

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