Electron microscopy studies

Trananisskm ekclron microscopy observations were carried out with a Jeol 200 CX operated at 200 kV. In order to avt fusion of the sanp es, ibe experiments were carried out on areas that make between 50 to 100 pm c tbidui s. Electron microscc y was applied to crystals that have the form of a leaf (ng.8.60). 

Analysis of figure 8.60 allowed us to observe stacking of molecules of ai-acid glycoprotein. In fact, dilTcrenl types of constraints, that correspond to objects of diflcrcnt nature (protein matrix, carbohydrate residues and lead acetate), arc observed (not shown) 

Diffraction studies obtained on a leaf yield Effused spots (Fig. 8.61) characteristic of a fiber pattern of a helical stnictuie of macromolecules. This result is in good agreement with th obtained with the X-ray ITraction studies and is associated with the structure ofthe carbohydrate residues (Fig 8.58) 

The distance h between two successive atoms within the carbohydrate skeleton was obtained from the position of the higher spot located at the 12th layer of the vertical azimuth, h was found equal to about 1 A. 

Therefore, while X-ray diffraction studies allowed the to detect the presence of 5 carbohydrates, electron microscopy diffraction studies allowed us to obtain information concerning the distance between the neighboring atoms within one carbohydrate residue. 

---

The crystal stmcture of PPT is pseudo-orthorhombic (essentially monoclinic) with a = 0.785/nm b = 0.515/nm c (fiber axis) = 1.28/nm and d = 90°. The molecules are arranged in parallel hydrogen-bonded sheets. There are two chains in a unit cell and the theoretical crystal density is 1.48 g/cm. The observed fiber density is 1.45 g/cm. An interesting property of the dry jet-wet spun fibers is the lateral crystalline order. Based on electron microscopy studies of peeled sections of Kevlar-49, the supramolecular stmcture consists of radially oriented crystaUites. The fiber contains a pleated stmcture along the fiber axis, with a periodicity of 500—600 nm. 

The mechanism for coercivity in the Cr—Co—Fe alloys appears to be pinning of domain walls. The magnetic domains extend through particles of both phases. The evidence from transmission electron microscopy studies and measurement of JT, and anisotropy vs T is that the walls are trapped locally by fluctuations in saturation magnetization. 

Bernaerts, D. and Amelinckx, S., Electron microscopy study of coiled carbon tubules. In Handbook of Microscopy, Vol. 3, ed. S. Amelinckx,... 

Electron microscopy studies were performed at the Centre Interdepartamental de Microscopie Electronique (CIME), Ecole Polytechnique Fdddrale de Lausanne. We are grateful to the Brazilian Council for Scientific and Technologic Research (CNPq) and the Swiss National Science Foundation for financial support. 

Khmenkov M, Nepijko S, Kuhlenbeck H, Baiimer M, Schldgl R, Ereund H-J. 1997. The structure of Pt-aggregates on a supported thin aluminum oxide film in comparison with unsupported alumina a transmission electron microscopy study. Surf Sci 391 27-36. 

E. L. Nurmiaho-Lassila, S. Timonen, K. Haahtela, R. Sen, Bacterial colonization patterns of intact Pinus. syhe.siris mycorrhizospheres in dry pine forest soil an electron microscopy study. Can. J. Microbiol. 43 1017 (1997). 

Franceschini V., Sbarfoati A. and Zancanaro C. (1991). The vomeronasal organ in the frog, Rana esculenla — an electron-microscopy study. J Submicros Cytol Pathol 23, 221-231. 

Kraushaar BS, Nirschl RP. Tendinosis of the elbow (tennis elbow). Clinical features and findings of histological, immunohistochemical, and electron microscopy studies. J Bone Joint Surg Am 1999 81(2) 259-278. 

JV Greiner, DR Korb, HI Covington, DG Peace, MR Allansmith. (1982). Human ocular mucus Scanning electron microscopy study. Arch Ophthalmol 100 1614-1617. 

Nitrogen adsorption isotherms were measured with a sorbtometer Micromeretics Asap 2010 after water desorption at 130°C. The distribution of pore radius was obtained from the adsorption isotherms by the density functional theory. Electron microscopy study was carried out with a scanning electron microscope (SEM) HitachiS800, to image the texture of the fibers and with a transmission electron microscope (TEM) JEOL 2010 to detect and measure metal particle size. The distribution of particles inside the carbon fibers was determined from TEM views taken through ultramicrotome sections across the carbon fiber. 

Shinn, J. H. Vermeulen, T. "Scanning Electron Microscopy Study of the Solubilization of Coal Under Mild Conditions". Paper submitted for presentation at Scanning Electron Microscopy Symposium, Washington, D.C., April 1979. 

Plenge-Bonig, A., Kromer, M. and Buttner, D.W. (1995) Light and electron microscopy studies on Onchocerca jakutensis and O. flexuosa of red deer show different host-parasite interactions. Parasitology Research 81, 66-73. 

Trichinella spiralis induction of the basophilic transformation of muscle cells by synchronous newborn larvae. II. Electron microscopy study. Parasitology Research 84, 823-827. 

TEG structure refinement has distinctly observed in electron microscopy studies of the oxidized TEG powders subjected to the repeated thermal shock. In this case the size of TEG macropores was equal to 1.5-2 pm that is essentially lower that for source TEG. Figure 2 presents SEM images of the source TEG particle (a) and TEG particle oxidized by sulfuric acid and re-exfoliated at 800°C (b). 

Some other situation is realized in a case of TEG-tin CMs. Electron microscopy studies of the obtained TEG-Sn powders revealed the uniform coverage of TEG surface by tin particles. Tin particles are of spherical shape and their sizes are about 40-80 nm, i.e. somewhat higher than in a case of silicon particles. Low scatter of particle sizes is observed as in a case of TEG-silicon system. However, as it is clearly seen from the data of the X-ray structure analysis (Figure 4) tin particles deposited on the surface of graphite support are in crystalline state. The distinct and narrow tin reflections at the X-ray diffraction pattern evidence this fact. 

Fig. 12.8 Electron microscopy study of a PDMS-Si02-CaO ormosil (A) Original HRTEM image of the amorphous matrix, (B) filtered HRTEM image and (C) Fourier transform pattern. Distances up to 0.53 nmfor (Si04)4-can be observed in the filtered image, indicating the presence of Ca2+ between the tetrahedra.

An electron microscopy study by Mullen et al. (1989) showed that Cd2+, Cu2+ and La3+ accumulated on the cell surface of Bacillus cereus, B. subtilis, E. coli and Pseudomonas aeruginosa as needle-like, crystalline precipitates, while Ag+ precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasm. The needle-like and hexagonal precipitates were also found for the biosorption of Ni2+ on the cell surface of P. fluorescens 4F39 at pH 9 and it was suggested as a microprecipitation process that followed on ion exchange (Lopez et al. 2000). 

Light scattering and electron microscopy studies of aqueous PVME solutions and PVME microgels were carried out by Arndt et al. [329,330]. They noted that the Mw of PVME in water was always higher (up to 20 times) than its value (Mw = 46 000gmoH) determined in organic solvent (butanone), even for dilute aqueous PVME solutions well below the phase-separation temperature [330]. Moreover the molar masses of the polymer in water depended on solution preparation conditions. The authors concluded that PVME does not exist as isolated chains in water, but forms loose aggregates (Rh = 200-220 nm) which decrease in size as the solution temperature passes... 

Titania films prepared by the methods described above are, however, just partially crystalline. Although WAXS patterns indicate formation of anatase crystals of ca. 10-12nm in size (Fig. 9.3a), the electron microscopy study demonstrates that the elongated crystals are actually embedded into an amorphous mesoporous matrix (Fig. 9.3c). The degree of crystallinity for such films usually does not exceed 60% attempts to increase it by calcination at higher temperatures cause uncontrolled crystal growth, which leads to collapse of mesoporos-ity and a drastic decrease in the surface area (Fig. 9.3d). 

In non-neuronal cells, electron microscopy studies reveal very complex endosomal compartments composed of a highly dynamic array of heterogeneous tubulovesicular-membrane structure extending from close vicinity to the plasma membrane to the cell interior, reaching the boundaries of the Golgi apparatus. Presynaptic terminals have similar endosomal systems, albeit less extensive [73, 74]. 

Tao-Cheng, J. H. and Zhou, F. C. Differential Polarization of serotonin transporters in axons versus soma-dendrites an immunogold electron microscopy study. Neuroscience 94 821-830, 1999. 

M. H. Tosten and M. J. Morgan, Transmission Electron Microscopy Study of Helium-Bearing Fusion Welds , WSRC-TR-2005-00477, November, 2005. 

Voigt-Martin et al. [13] have used MICE to solve the stmcture of 4-(4 -(N,N-dimethyl)aminobenzylidene)-pyrazolidine-3,5-dione at 1.4A in projection using 42 reflections. The potential maps do not resolve atoms with these data and models have to be fitted to the map density in a way reminiscent of macromolecular crystallography. This can pose problems in structure validation which were overcome in this case by simulation calculations. There is an excellent agreement between the solution and independent model building and high resolution electron microscopy studies. 

Fiebrig, L, Harding, S.E., Rowe, A.J., Hyman, S.C., and Davis, S.S., Transmission electron microscopy studies on pig gastric mucin and its interactions with chitosan, Carbohydr. Polym., 28 239-244 (1995). 

Another approach is to perform ex situ reactions and insert the sample into a high vacuum system without exposure to ambient conditions. Incorporating N2 glove boxes or reactor systems with X-ray photoelectron spectroscopy (XPS) sample handling can also provide information that is closer to operational conditions. In a similar manner ex situ reactions and sample handling are starting to be apphed to electron microscopy studies. Commercially available sample transfer systems will accelerate the application of this methodology. 

Lupulescu AP, Birmingham DJ. 1976. Effect of protective agent against lipid-solvent-induced damages Ultrastructural and scanning electron microscopial study of human epidermis. Arch Environ Health 31(l) 33-36. 

These results were confirmed by an electron microscopy study using a freeze-etching replication technique (1 ). The aim of this technique was to conserve the real gel structure by blocking any diffusion processes in the gel sample by the freezing action of liquid nitrogen. The three-dimensional network is then recovered... 

Barron,V Galvez, N. Hochella Jr., M.E. Tor-rent, J. (1997) Epitaxial overgrowth of goethite on hematite synthesized in phosphate media A scanning force and transmission electron microscopy study. Am. Min. 82 1091-1100... 

Vacancy ordering in y-Fe203 Synchroton X-ray powder diffraction and high resolution electron microscopy studies. J.Phys. Chem.-Solids 10 35-43... 

---