Micromorphological studies

Sprucewood holocellulose was treated with an endo-p-1,4-mannanase isolated from Aspergillus niger and an endo-/3-1,4-xylanase, two avicelases, and a cellobiohydrolase C isolated from Trichoderma viride. The mannanase hydrolyzed about a quarter of the mannan in 2-3 days without xylan or cellulose degradation. The xylanase hydrolyzed about half the xylan with 10% mannan solubilization. The three cellulases hydrolyzed up to 45% of the cellulose and 20% of the xylan, accompanied by 40-70% solubilization of the mannan. Combined xylanase-mannanase treatment hydrolyzed about half the xylan and mannan. Addition of mannanase to to cellulose-treated samples increased the degradation of the cellulose and mannan. Micromorphological studies of the variously treated specimens revealed a loss of substances in P/Slf T, and adjacent zones of S2 of the tracheid wall. 

The living floors of these houses provided substantial information on both contents and context (Fig. 5.6). Several techniques were used to study the house floors. Paul Goldberg of Boston University did the micromorphology study. Figure 5.7... 

In addition, in this sample (Fig. 5.7) there is a gap or crack between the house floor and the upper deposits, likely left by the decay of vegetation, perhaps mats on the floor. During excavation the upper deposits peeled away easily from the more compact house floor. Micromorphological studies revealed the nature of this house floor and the deposits that accumulated on it, both during and after use. 

Cell death by apoptosis, a phenomenon that is increasingly considered the ultimate cause of many diseases, is also one of the patent toxic manifestations of okadaic acid. Micromorphological studies have demonstrated a parallel between the hyperphosphorylation of neuronal cytoskeletal proteins in Alzheimer disease and that produced by a treatment of cultured rat neurones with okadaic acid, which is accompanied by rounding of the cellular bodies and neurite degeneration. DNA fragmentation and neuronal death are inhibited by the presence of cycloheximide and by the caspase inhibitor benzoyloxycarbonyl-Val-Ala-Asp-O-methoxy-fluoromethyl ketone (ZVAD) [134, 135], Okadaic acid was reported to be an apoptopic agent in rat thymocytes, because it causes... 

When micromorphological studies fail, the investigator then proceeds to the electron microscopy for topography, to the EBP, ESCA, or SEM with energy dispersive X-ray analysis (EDXRA) for elemental analysis. 

As has been shown by micromorphological studies, micas exhibit a lamellar structure (Figure 1). The thickness of the lamellae was found to vary between about 0.05 and 0.1 /tin. Examination of electron micrographs obtained from the < 1 /xm fraction of different mica species (Figure 2) revealed that the frequency distribution of particle thickness centers around... 

French, C. A. I. and Ch. French (2002), Geoarchaeology in Action Studies in Soil Micromorphology and Landscape Evolution, Routledge, London. 

Atomic force microscopy and attenuated total reflection infrared spectroscopy were used to study the changes occurring in the micromorphology of a single strut of flexible polyurethane foam. A mathematical model of the deformation and orientation in the rubbery phase, but which takes account of the harder domains, is presented which may be successfully used to predict the shapes of the stress-strain curves for solid polyurethane elastomers with different hard phase contents. It may also be used for low density polyethylene at different temperatures. Yield and rubber crosslink density are given as explanations of departure from ideal elastic behaviour. 17 refs. 

A major advantage of Raman spectroscopy in the chemical characterization of pollen is its applicability in situ. The pollen grains in this study were investigated without prior purification or extraction procedures, which has been the case in most other investigations on pollen composition so far [45, 46, 57, 58]. Using Raman microspectroscopy on sections of snap-frozen samples, the chemical composition and very likely also their ultrastructure remain unaltered, and the co-localization of individual components could be studied in the context of pollen micromorphology, simultaneously in very short... 

If flow is continuous, or strains are large, droplets or domains deform greatly or burst, and the above expressions for the moduli are inapplicable. Although there have been some experimental and theoretical studies of the droplet size and size distributions in such flows (see Section 9.2.2), there seem to be few theoretical results that allow prediction of the stresses in such flows. These flows are immensely complex the stresses depend not only on the viscoelastic characteristics of the two components of the emulsion, but also on the micromorphology of the phases, which, in turn, depends on the history of the flow. 

O. Nast, S. Rauscher, H. Jungblut, and H.-J. Lewerenz, Micromorphology changes of silicon oxide on Si(lll) during current oscillations A comparative in situ AFM and FllR study, J. Electroanal. Chem. 422, 169, 1998. 

Metal detectors Instruments that emit an electromagnetic field that is disrupted by the presence of metal objects in the ground, used for finding buried metal objects. Micromorphology The study of anthropogenic sediments at a microscopic level. Microscopic Visible only with magnification. 

While these studies provide valuable information on the influence of environmental factors on the penicillin production process, they are of limited value from the viewpoint of metabolic engineering of morphology. This is because they aimed at describing the complex interactions between mechanical forces, growth, and rheology, rather than the influence of micromorphology on the production process. 

The dependence on composition and processing of the micromorphological phase structure and mechanical properties of both unfilled and glass-filled recycled PP-HDPE blends is demonstrated in this study. 

Butyl acrylate-methyl methacrylate copolymer latices with a core-shell structure were prepared by a sequential emulsion polymerisation technique. SEM and transmission electron microscopy studies undertaken on the polymer dispersions, powders obtained by spray drying and latices prepared by redispersing the powders in water revealed the influence of polymerisation parameters on the micromorphology of the starting latices, and correlations between the dimensional and micromorphological characteristics of the starting latices, the powders and the redispersed latices. 8 refs. 

The synthesis and characterization of poly(hexamethylene sebacate-tiimethyl-siloxane) block copolymers, prepared by coupling Cl- or McjNH-terminated dimethylsiloxanes with OH-terminated poly(hexamethylene sebacate), have been studied. The copolymers containing 19—90% siloxane were characterized by n.m.r., viscosity, DSC and CPC. All the polymers were found to be crystalline. The copolymers containing <69% siloxane, when cast from solution or melts, indicated a reduction in spherulite size as the siloxane concentration increased, although only a small m.pt. depression was observed. All the copolymers have critical surface tensions similar to dimethylsiloxane homopolymers. Polycarbonate-Siloxane Copolymers.—A model has been proposed to predict the micromorphology and mechanical properties of block copolymers of bisphenol-A polycarbonate and poly(dimethylsiloxane). N.m.r. data upon 65 35 (wt%) copolymer of poly(dimethylsiloxane) and bisphenol-A polycarbonate, with block lengths of 20—100 monomer units, were found to be in agreement with the predictions of a spin-diffusion model. ... 

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