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protocols for cuticle matrix characterization at the histochemistry and electron microscopy levels were applied, compared, and adapted, to gain information on the exocuticle and endocuticle matrix composition. The specific goals of this study were as follows
Abstract
Use of autoradiography and scanning electron microscopy, coupled with potentiometric and radionalytical investigation techniques, allows to confirm experimentally that the rate of Cl−→SO 4 2− conversion of different anion resins at 0.006N solution concentration is not controlled) by ion interdiffusion and that sulfate penetration into the resin bead occurs according to a progressive conversion mechanism.
Abstract
Potsherds were analyzed chemically by four different techniques. Results are compared for many elements. The effect of temper appears as a problem because of the inhomogeneity of the bulk. PIXE and neutron activation are powerful and complementary methods to obtain element concentrations for proveniance studies. Also scanning electron microscopy and the electron microprobe are very useful to detect and analyze the tempers. Thus it is possible to gather data on the potter technology. In conclusion the use of a proton microprobe seems to be a promising instrument for versatile analyses.
Abstract
Commercial light-cured dental composites were used in this study. Two laboratorial composites, Resilab (Wilcos/Brazil), Epricord (Kuraray/Japan) were compared under cured and uncured conditions. Thermal analysis, infrared spectroscopy and scanning electron microscopy were used to evaluate the dental composites. The mass change and heat flow signals (TG–DSC) were recorded simultaneously by using STA 409 PC Luxx (NETZSCH), in the 25–800 °C temperature range at a heating rate of 10 °C/min under nitrogen atmosphere (70 mL/min). Employing thermo-microbalance TG 209 C F1 Iris (NETZSCH) coupled to the BRUKER Optics FTIR TENSOR, the samples were analyzed by combined thermogravimetric and spectroscopic methods (TG–FTIR). The initial sample mass was about ~12 mg, the data collection have been done in the 35–800 °C temperature range at a heating rate of 20 K/min in nitrogen atmosphere (flow rate: 40 mL/min). Finally, superficial topographic was analyzed by scanning electron microscopy (SEM). Dental composite evaluation suggests a high thermal stability and inorganic content in RES D sample. Degrees of conversion (DC) values were almost the same and there was no direct relationship between DC and amount of particles and size. Similar compositions were found in all samples.
Abstract
Semisolid phospholipid preparations have been well known for several years and are still investigated as drug carrier systems, e.g. for potential cancer therapy. They may be applied parenterally as semisolid vesicular phospholipid gels suitable as implants for sustained drug release or as liposomal preparations after redisperging the stable storage form. Due to enhanced stability, mixtures of hydrated phospholipids and cholesterol are more suitable than natural unsaturated phospholipids. In order to describe characteristics of vesicular phospholipid gels, only a few techniques may be useful. Especially the structure of the semisolid preparation is not yet completely understood. We tried to get some more information about these systems by using a combination of freeze-fracture electron microscopy, differential scanning calorimetry and rheometry to elucidate, on the one hand, the inner structure or homogeneity and, on the other, the thermotropic phase transition of the three-dimensional lipid network and the temperature dependency of the fluidity/viscosity of the samples. Using freeze-fracture electron microscopy we found coexisting phospholipid domains of lamellar sheets and vesicular structures. With the help of differential scanning calorimetry the reasons for the different phase behaviour were elucidated. Rheometric measurements show increased intermediate viscosity at the thermotropic phase transition of the lipid bilayers, possibly induced by interacting membrane defects.
Plankton samples collected from a yellow watered bog pool of the mesotrophic “Călăţele Pădurii” peat bog (Romanian Western Mountains, Transylvania), exhibited an outstandingly rich Mallomonas population. The observations carried out by light and scanning electron microscopy revealed that the population belongs to Mallomonas intermedia Kisselev. Based on the presence of lance head bristles, distributed all over the cell armour (except few anterior collar, unilaterally serrated ones), it became evident that the population belong to the nominate variety (var. intermedia). Mallomonas intermedia var. saliceaensis formerly described from Transylvania differs by the type variety by the presence of exclusively serrated bristles. The present finding proved that Mallomonas intermedia could not be properly identified at infraspecific level solely based on the ultra structure of scales, without knowing the structure of bristles, too.
scanning electron microscopy. In: J. J. Bozzola, L. D. Russel (eds) Electron Microscopy. Jones and Bartlett Publishers, London, pp. 40-64. Specimen preparation for scanning electron microscopy
N. A. , Craven J. P. , Donald A. M. , Terentjev E. M. , Thiel B. L. Topographic contrast of partially wetting water dropelts in environmental scanning electron microscopy , Journal of Microscopy , Vol. 204 , No. 2
) 15. Fujii T , AritaM, Takahashi Y , Fujiwara I : In situ transmission electron microscopy analysis of conductive filament during solid electrolyte resistance
Abstract
X-ray fluorescence, using the fundamental parameters method for matrix correction, is used routinely for quantitative analysis in our group. The accuracy of this method has been demonstrated with a Nd:YAG (Nd:Y3Al5O12) laser crystal. The neodymium concentration was determined relatively to the yttrium concentration by X-ray fluorescence using241Am for excitation. The yttrium-aluminum ratio was confirmed by scanning electron microscopy (SEM-EDX). Although there was a 10% discrepancy for yttrium due to the uncertainty in the neutron capture cross-section, the fluorescence results for aluminum and neodymium were in very good agreement with neutron activation analysis (NAA) results. Based on this agreement, the Nd:YAG sample will be used in future NAA calibration measurements.
