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SEM Study (sem + study)
Selected AbstractsAn SEM study of the jaws of Haplognathia rosea and Rastrognathia macrostoma (Gnathostomulida), with a preliminary comparison with the rotiferan trophiACTA ZOOLOGICA, Issue 1 2000Martin V. Sørensen The preparation of gnathostomulid jaws for scanning electron microscopy is demonstrated, and descriptions of the jaws from Haplognathia rosea and Rastrognathia macrostoma are given. These jaws represent two different gnathostomulid jaw types, namely the ,compact type' and the ,basket type'. The described structures are compared with sclerites in the rotifer trophi, and some homologies are suggested. The observations support a close relationship between Gnathostomulida and Rotifera. [source] Pittosporum undulatum Vent. grown in Portugal: secretory structures, seasonal variation and enantiomeric composition of its essential oilFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2007Nicolau J. Ferreira Abstract Aerial parts of Pittosporum undulatum were collected fortnightly for 1 year at the Parque de Saúde de Lisboa. Collective samples of two populations were investigated, i.e. from pruned and non-pruned trees, and in addition samples from one pruned and one non-pruned individual. An SEM study of the aerial parts showed the presence of non-glandular T-shaped trichomes, and capitate trichomes with an elongated stalk and two to four round-shaped cells on the top. Numerous canals were seen at the level of the capsule wall as well as in the leaves and stems. Essential oil samples were isolated from the (deep-frozen) aerial parts by hydrodistillation to estimate the oil yields, and by distillation,extraction to determine their percentage composition, and analysed by GC and GC,MS. Monoterpenes (59,97%) were dominant in all oils, sabinene (5,58%), limonene (2,37%) and terpinen-4-ol (4,27%) being the major components, although in different relative amounts during the year of collection. Benzyl benzoate (8%) and benzyl salicylate (10%) attained high relative amounts in the oils from fully developed flowers, whereas in the oils from the other plant parts their relative amounts did not exceed 1%. The enantiomeric ratio of sabinene, limonene and terpinen-4-ol was investigated in the leaf, flower and capsule oils, showing dominance of the (+)-forms and homogeneity between all the oil samples. Copyright © 2006 John Wiley & Sons, Ltd. [source] A novel microencapsulation of neem (Azadirachta Indica A. Juss.) seed oil (NSO) in polyelectrolyte complex of ,-carrageenan and chitosanJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009Nirmala Devi Abstract Microcapsules containing neem (Azadirachta Indica A. Juss.) seed oil (NSO) were prepared by encapsulation of natural liquid pesticide NSO in a polyelectrolyte complex of ,-carrageenan and chitosan. The optimum ratio between carrageenan and chitosan to form a stable polyelectrolyte complex was found as 1 : 0.36. The microencapsulation method for NSO loading was also optimized. SEM study demonstrated that the surface of the microcapsules became more irregular as oil loading increased. The release rates of NSO were studied by varying the percentage of oil loading, concentration of cross-linking agent, and polymer concentration. Fourier transform infrared spectroscopy (FTIR) study confirmed the complex formation between ,-carrageenan and chitosan. Differential scanning calorimetry (DSC) and FTIR study indicated the absence of any significant interaction between polyelectrolyte complex of ,-carrageenan -chitosan and NSO. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Blends of triazine-based hyperbranched polyether with LDPE and plasticized PVCJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Jyotishmoy Borah Abstract Triazine-based hyperbranched polyether was obtained by earlier reported method and blended with low density polyethylene (LDPE) and plasticized poly(vinyl chloride) (PVC) separately to improve some desirable properties of those linear polymers. The properties like processability, mechanical properties, flammability, etc. of those linear polymers were studied by blending with 1,7.5 phr of hyperbranched polyether. The mechanical properties were also measured after thermal aging and leaching in different chemical media. SEM study indicates that both polymers exhibit homogenous morphology at all dose levels. The mechanical properties like tensile strength, elongation at break, hardness, etc. of LDPE and PVC increase with the increase of dose level of hyperbranched polyether. The flame retardant behavior as measured by limiting oxygen index (LOI) for all blends indicates an enhanced LOI value compared to the polymer without hyperbranched polyether. The processing behavior of both types of blends as measured by solution viscosity and melt flow rate value indicates that hyperbranched polyether acts as a process aid for those base polymers. The effect of leaching and heat aging of these linear polymers on the mechanical properties showed that hyperbranched polyether is a superior antidegradant compared to the commercially used N -isopropyl- N -phenyl p -phenylene diamine. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 648,654, 2007 [source] Evaluation of penetration and adaptation of three different sealers: a SEM studyJOURNAL OF ORAL REHABILITATION, Issue 9 2003S. Sevimay Summary, In this study, dentinal penetration and adaptation of three endodontic sealers were evaluated by using scanning electron microscope (SEM). Seventeen recently extracted, human maxillary anterior teeth were used. After the crowns were removed from the cementoenamel junction, the root canals were instrumented. The teeth were then randomly divided into three groups of five roots each and two teeth were used as controls. The smear layer was removed with EDTA and NaOCl. The canals were obturated with AH 26, CRCS, RSA sealers and gutta-percha using lateral condensation technique. Each root was sectioned longitudinally and then prepared for SEM evaluation. The SEM results showed that AH 26 was the best sealer penetrating into dentinal tubules and adapted to dentinal walls when compared with the CRCS and RSA. The CRCS and RSA occluded the orificies of dentinal tubules. The RSA showed that the penetration was less than AH 26 and more than CRCS. [source] Characterisation of carbonaceous materials using Raman spectroscopy: a comparison of carbon nanotube filters, single- and multi-walled nanotubes, graphitised porous carbon and graphiteJOURNAL OF RAMAN SPECTROSCOPY, Issue 3 2009H. M. Heise Abstract Multi-walled carbon nanotube (MWCNT) filters have been recently synthesised which have specific molecular filtering capabilities and good mechanical strength. Optical and scanning electron microscopy (SEM) reveals the formation of highly aligned arrays of bundles of carbon nanotubes having lengths up to 500 µm. The Raman spectra of this material along with four other carbonaceous materials, commercially available single-walled carbon nanotubes (SWCNTs) and MWCNTs, graphitised porous carbon (Carbotrap) and graphite have been recorded using two-excitation wavelengths, 532 and 785 nm, and analysed for band positions and shape with special emphasis paid to the D-, G- and G,-bands. A major difference between the different MWCNT varieties analysed is that G-bands in the MWCNT filters exhibit almost no dispersion, whereas the other MWCNTs show a noticeable dispersive behaviour with a change in the excitation wavelength. Spectral features similar to those of the MWCNT filter varieties were observed for the Carbotrap material. From the line shape analysis, the intensity ratio, ID/IG, of the more ordered MWCNT filter material using the integral G-band turns out to be two times lower than that of the less ordered MWCNT filter product at both excitation wavelengths. This parameter can, therefore, be used as a measure of the degree of MWCNT alignment in filter varieties, which is well supported also by our SEM study. Copyright © 2008 John Wiley & Sons, Ltd. [source] Surface Morphology of the Emu (Dromaius novaehollandiae) TongueANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2010M. R. Crole With 18 figures Summary Despite numerous morphological studies on the avian tongue, very little meaningful information is currently available on the surface features of this organ using scanning electron microscopy (SEM). The only SEM description of a ratite tongue is that of the ostrich, although the descriptions are brief and superficial. This SEM study of the emu tongue confirms and compliments the comprehensive macroscopic and histological data available for this commercially important species. The tongues of five emus were fixed, cut into blocks representing the dorsum, ventrum and root and routinely processed for SEM. Three morphologically distinguishable surface types (desquamating, non-desquamating and lymphoepithelium) related to peculiarities in surface cell shape and status (desquamating or non-desquamating), cell surface modifications and distribution of gland openings, and which showed a regional distribution, could be identified. Three basic types of cell surface modifications (microplicae, microvilli and cilia) were observed, with microvilli and cilia being described for the first time in an avian tongue by SEM. The desquamating surface cells fulfil a mechanical protective function, whereas the microplicae, microvilli and cilia appear to be adaptations for the trapping and spreading of mucus which also fulfils a protective function. [source] Comparative SEM study of the marginal adaptation of white and grey MTA and Portland cementAUSTRALIAN ENDODONTIC JOURNAL, Issue 1 2007Maryam Bidar dds Abstract The use of a suitable substance that prevents egress of potential contaminants into the periapical tissues is important in endodontic surgery. The aim of the present study was to compare the marginal adaptation of three root-end filling materials (white mineral trioxide aggregate (MTA), grey MTA and Portland cement), using scanning electron microscopy. Seventy-five single-rooted extracted human teeth were used. The canals were instrumented and filled with gutta-percha. Following root-end resection and cavity preparation, root-end cavities were filled with white MTA, grey MTA or Portland cement. Using a diamond saw, roots were longitudinally sectioned into two halves. Under scanning electron microscopy, the gaps between the material and dentinal wall were measured. The data were analysed using Kruskal,Wallis test. The mean of the gap in grey MTA, white MTA and Portland cement was 211.6, 349 and 326.3 µm, respectively. The results indicate that the gap between grey MTA and the dentinal wall is less than other materials, but there was no significant difference between the materials tested in this study (P > 0.05). [source] | ||||||||||||||||