Scanning Electron Microscopy

Permanent link to open access version: http://hdl.handle.net/10523/10586

Materialising Ancestral Madang documents the emergence of pottery production processes and exchange networks along the northeast coast of New Guinea during the last millennium before the present. This dynamic period in the Pacific’s human past involved important fluctuations to people’s mobility, social interaction, and technological organisation. It therefore remains crucial to understanding and historicising the expansive maritime subsistence trading networks that famously characterised the coast in the late 19th and early 20th centuries. This book investigates these transformations by exploring the archaeology of Madang District; the heart of the Madang exchange network that revolved around the production and distribution of distinctive red-slipped pots. Potsherds of this style have been previously found spanning a 200 km radius, reaching Karkar Island, the Bismarck Archipelago, and even the New Guinea Highlands. By combining archaeological survey, excavation, craft ethnography, and archaeometric analyses, the volume systematically delineates the production groups that were working within this broader community of practice. The study shows that pre-colonial potters made use of a range of local raw materials and were free to improvise with their forming and decorating techniques but learned and reproduced similar technological sequences over the past 500–600 years. It is likely that social restrictions permitted only potters from a small number of clans to produce ceramics and that the finished vessels were then distributed both informally within the local area and strategically during extensive trade voyages along the northeast coast of New Guinea. These results therefore cast light on an important but previously obscured aspect of Pacific culture history and provide a model for how craft production and exchange processes have manifested and co-modified across the generations

Ordered (SBA-15) and disordered (KIL-2) mesoporous silica supports have been synthesized and used for incorporation of titania with different Ti/Si molar ratios (1/2, 1/1, 2/1) via sol–gel impregnation method. Titanium isopropoxide and aqueous titania sol prepared by low-temperature sol–gel processing were used as a source of titania. Characterization by powder X-ray diffraction (XRD), nitrogen sorption measurements, scanning electron microscopy (SEM) and UV–vis–NIR diffuse reflectance spectroscopy (DRS) has been carried out to investigate the chemical framework and morphology of powders. The photocatalytic degradation of isopropanol in the gaseous medium was selected as a probe reaction to test the photoactivity of powders and to verify the potential application of these materials for air remediation. It was found that the titania source, Ti/Si molar ratio and the type of silica support influenced the functional properties of the material, which were evaluated by adsorption capacity and photocatalytic activity in the gas–solid reactor. The adsorption capacity of isopropanol was the highest in the presence of the SBA-15-supported materials. The photoactivity results indicated that the powders which were prepared using SBA-15 as a silica support and a Ti/Si molar ratio of 1/1 were the most active towards isopropanol oxidation monitored in situ by FT-IR spectroscopy.

Aim  To evaluate marginal seal, water sorption, solubility and loss of mass after brushing of several temporary filling materials.Methodology  For marginal seal, Class I cavities, including endodontic access preparations, were made in human molar teeth and restored using one or other of several temporary filling materials (n = 10): zinc oxide/calcium sulphate-based cement (Cavit, 3M,ESPE, St. Paul, MN, USA), zinc oxide/eugenol cement (IRM, Dentsply Caulk, Milford, DE, USA), glass ionomer cement (Vidrion R, SSWhite, Rio de Janeiro, RJ, Brazil) or a dimethacrylate-based filling (Bioplic, Biodinâmica, Londrina, PR, Brazil). Dye penetration was assessed after thermocycling and immersion in 0.5% basic fuchsine solution. For water sorption, solubility and loss of mass analyses, disc-shaped specimens were made. Water sorption and solubility were evaluated by mass alteration after storage in distilled water for 7 days (n = 7). Loss of mass was calculated based on the difference of mass after abrasion with a toothbrush (n = 5), and surfaces were analysed by SEM. Data of water sorption, solubility and loss of mass were submitted to anova and Tukey’s test, and marginal sealing data to Kruskal–Wallis test (P < 0.05).Results  Statistically significant differences were observed for marginal sealing (P < 0.0001), water sorption (P < 0.01), solubility (P < 0.01) and loss of mass (P < 0.05). Bioplic had the best marginal seal. Cavit had the greatest water sorption and solubility. Vidrion R and Bioplic had the lowest solubility. Loss of mass after brushing was higher for Cavit, followed by Bioplic, IRM and Vidrion R. Cavit and Vidrion R were worn aggressively by brushing.Conclusions  The resin-based temporary filling Bioplic produced the best marginal seal, and was associated with the lowest water sorption, solubility and loss of mass.

Biological and technical failures of implants have already been reported. Mechanical factors are certainly of importance in implant failures, even if their exact nature has not yet been established. The abutment screw fracture or loosening represents a rare, but quite unpleasant failure. The aim of the present research is an analysis and structural examination of screw thread or abutment loosening compared with screw threads or abutment without loosening. The loosening of screw threads was compared to screw thread without loosening of three different implant systems; Branemark (Nobel Biocare, Gothenburg, Sweden), T.B.R. implant systems (Benax, Ancona, Italy) and Restore (Lifecore Biomedical, Chaska, Minnesota, USA). In this study broken screws were excluded. A total of 16 screw thread loosenings were observed (Group I) (4 Branemark, 4 T.B.R and 5 Restore), 10 screw threads without loosening were removed (Group II), and 6 screw threads as received by the manufacturer (unused) (Group ...

In the treatment of photoaged skin, glycolic acid works by removing superficial portions of the epidermis and stimulating dermis regeneration. Vitamins A, C, and E should stimulate collagen production and antioxidants should prevent free radical damage and skin aging. However, the effectiveness of different therapies has often relied on subjective methods of assessment. Histologic analysis has seldom been used because of the drawback of permanent scarring. In the literature, the use of a quantitative method for the assessment of facial rejuvenation has been described: the silicone replica technique. The authors&#39; aim was to promote and recommend the use of this technique and, in particular, to test the effect of glycolic acid and multivitamin- and antioxidant-based products on skin texture. The authors performed a prospective, randomized, double-blind, controlled study on 30 women treated topically in the outer canthal region (crow&#39;s-feet area). Patients were divided into thr...

Phosphate-based glasses have been examined in many studies as a potential biomaterial for bone repair because of its degradation properties, which can be controlled and allow the release of various elements to promote osteogenic tissue growth. However most of these experiments studied either tertiary or quaternary glass systems. This study investigated a qinternary system that included titanium dioxide for degradation rate control and zinc that is considered to have a role in bone formation. Zinc and titanium phosphate glass discs of different compositions were melt synthesized and samples of each composition was tested for different physical, chemical and biological characteristics via density measurement, X-ray diffraction, differential thermal analysis, mass loss, ion release, scanning electron microscopy, biocompatibility studies via live/dead assays at three time points (day 1, 4, and 7). The results showed that the glass was amorphous and that the all thermal variables decreas...

Acid mine drainage (AMD) – characterized by high acidity and elevated sulfate and metal concentrations – represents a big environmental concern. Biological sulfate reduction has become an alternative to the classical physicochemical methods. In this study, domestic wastewater (DW) was tested as a cost-effective carbon-source for the remediation of AMD. Sediments from Tinto River, an extreme acidic environment with an elevated concentration of metals, were used as inoculum. Three anaerobic bioreactors with different microbial supports were fed with a 1:10 (v:v) mixture of synthetic AMD:DW. Around 50% of the organic matter present in the DW co-precipitated with the metals from the AMD previous to feeding the reactor. Therefore, the reactors had to be supplemented with an extra carbon-source (acetate) to achieve higher S elimination. Elevated removal efficiencies of chemical oxygen demand (COD) (&gt;88%), sulfate (&gt;75%), Fe (&gt;85%) and other dissolved metals (&gt;99% except for Mn...

Joining of dissimilar materials is of increasing interest for a wide range of industrial applications. The automotive industry, in particular, views dissimilar materials joining as a gateway for the implementation of lightweight materials. Specifically, the introduction of aluminum alloy parts into a steel car body requires the development of reliable, efficient and economic joining processes. Since aluminum and steel demonstrate

Epiphytic lichens are efficient air pollution bio monitors as they obtain nutrients, water and pollutants from the atmosphere. The aim of this study was at analyzing the surface of hyphae and the surface of the lichens Evernia prunastri (unwashed and washed in distilled water). Mass percentage of 26 selected elements: C, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sn, Sb, Hg, Pb and Bi was determined by scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDS). Mass percentage of: Na, Mg, V, Cr, Mn, Co, Ni, Zn, As, Cd, Sn, Sb, Hg, Pb was below the limit of detection of the applied method. The mass percentage of all other determined elements on the hyphae and surface of lichen was higher in unwashed samples, except for C, O, P, Fe, Cl, Ca and Cu. The elemental analysis of the unwashed lichen surface showed the prevalence of: O, C, Si, Cu and
Bi. Results obtained in the unwashed and washed lichen samples showed that the cleaning with water can be used in order to eliminate adhering materials. Indeed, most of elements of interest for the environmental contamination accumulated by the lichens were not
removed. SEM images showed particles that are flat, with irregular shape and edges, generally smooth and rounded indicating that the particles deposited were dry aerosol particles.

The exoskeleton of the lobster Homarus americanus is a multiphase biological composite material which consists of an organic matrix (crystalline α-chitin fibers and various types of non-crystalline proteins) and minerals (mainly calcite). In this study we discuss experimental data about the mesoscopic structure and the crystallographic texture (orientation distribution) of the α-chitin–protein fiber network in this material. The synchrotron measurements reveal very strong crystallographic textures of the α-chitin. According to these data, a large fraction of the α-chitin lattice cells is arranged with their longest axis parallel to the normal of the surface of the exoskeleton. Additionally, a smaller fraction of the α-chitin cells is oriented with their longest axis perpendicular to the cuticle surface. These structural investigations reveal the pronounced role of crystallographic orientation distributions in mineralized biological composite materials which may be of relevance for an improved understanding of biological and bio-inspired nano-composites.