Characterization of Ancient Egyptian Wall Paintings, the Excavations of Cairo University at Saqqara

The present study aims at characterizing some Egyptian wall paintings discovered during the excavations of Cairo University (since 1988 and recently in 2005) at Saqqara area in the south of Cairo. There, a number of tombs dating back to the 19th dynasty (c.1293–1185 BC) were discovered. The walls of these tombs are carved with bass and raised reliefs and painted with different colours. The characterization of the wall paintings was done by means of optical microscopy (OM), scanning electron microscopy (backscattered electron mode, BSE) equipped with an energy dispersive X-ray detector (EDS), micro XRF spectrometry (µ-XRF), and X-ray diffraction analysis (XRD). The analysis of the examined samples indicated that the blue pigment is Egyptian blue (Cuprorivaite), the green pigment is Egyptian green, the red pigment is red ochre, and the yellow pigment is a blended layer of yellow ochre and orpiment (As2S3). The results will help in providing an image concerning some painting materials used during the new Kingdom in ancient Egyp

Sol-Gel Derived Mg-Based Ceramic Scaffolds Doped with Zinc or Copper Ions: Preliminary Results on Their Synthesis, Characterization, and Biocompatibility

Glass-ceramic scaffolds containing Mg have shown recently the potential to enhance the proliferation, differentiation, and biomineralization of stem cells in vitro, property that makes them promising candidates for dental tissue regeneration. An additional property of a scaffold aimed at dental tissue regeneration is to protect the regeneration process against oral bacteria penetration. In this respect, novel bioactive scaffolds containing Mg2+ and Cu2+ or Zn2+, ions known for their antimicrobial properties, were synthesized by the foam replica technique and tested regarding their bioactive response in SBF, mechanical properties, degradation, and porosity. Finally their ability to support the attachment and long-term proliferation of Dental Pulp Stem Cells (DPSCs) was also evaluated. The results showed that conversely to their bioactive response in SBF solution, Zn-doped scaffolds proved to respond adequately regarding their mechanical strength and to be efficient regarding their biological response, in comparison to Cu-doped scaffolds, which makes them promising candidates for targeted dental stem cell odontogenic differentiation and calcified dental tissue engineering

Calcination study of crystalline limestone from Agiow Panteleimonas, Florina, Greece

The studied limestones are described as coarse-grained. Mineralogically they are very pure because they contain calcite 98.8%, dolomite 0.8% and traces of micas, quartz, chlorite, feldspars, hematite, amphiboles, epidote, pyrite, titanite, ilmenite and zircon. The organic material of the crystalline limestones was defined to be 0.8% and their insoluble residue 1%. From the SEM-EDS study, it was ascertained that the calcite.s crystals are extremely pure with mean content of CaO 55.14%, while the main admixture is MgO with an average of 0.57%. Chemically, the examining limestones are very pure with an average of CaO 53.67%. This percentage corresponds to a 95.8% CaO content and thus the Agios Panteleimonas limestones can be classified as high-calcium materials suitable for calcination. The beginning of calcination is set approximately at 750o C, while its completion according to the size of the cubic samples is noted between 1,000 and 1,150o C. The appearance of non-crystalline phase is noted during the progress of calcination at a percentage ranging from 1 to 18%. From the SEM-EDS study it can be evident that the calcination is developing uniformly from the periphery of the samples towards the core. The produced lime in the thoroughly calcined samples is of high quality with CaO values greater than 90%. As far as the trace elements are concerned, Ag enriches the produced lime, whereas none of these elements shows organic affinity. The trace elements Ba, La, Sc, Sm, Sr, U, V, Y and Zr show intermediate affinity. Many other elements were determined and remain under the detection limit almost under any calcination condition. It is concluded that the calcination conditions do not affect the elements behaviour. As far as the technological characteristics are concerned the examined limestones have an average dry apparent weight of 2.6 g/cm3. During the cubic samples calcination with an average edge of 1 cm, the calcination is completed at around 1,000o C and the dry apparent weight gets an average value of 1.4 g/cm3. The retention for a longer period of time in that temperature or the exposure to greater temperatures causes increase of the dry apparent weight that is shrinkage phenomena in cubic samples. Indeed, for calcination temperature of 1,150o C, values of dry apparent weight were counted up to 1.7 g/cm3. In cubic samples of mean edge of 2 and 4 cm, proportionate phenomena are being observed but not so intense. On the other hand, in cubic samples of mean edge of 6 and 8 cm the calcination progress is more normal and a lower value of the dry apparent weight is achieved in greater temperatures. It is noted then, that the quality of the produced lime from a given limestone does not only depend on the calcination conditions, but also on the limestone fragments size that will be calcined

Salt Damage on the Wall Paintings of the Festival Temple of Thutmosis III, Karnak Temples Complex, Upper Egypt. A Case Study

The present study aims to characterize the main deterioration mechanisms affecting the wall painting of the festival temple of Thutmosis III, in the Karnak temples complex, Upper Egypt. Several salt encrustations were observed on the painted surfaces, exhibiting different degrees and forms of decay. The morphology and the microanalysis of the contained mineral phases were studied using scanning electron microscopy together with an energy dispersive X-ray analysis system (SEM-EDS). The mineralogical characterization was performed using the X-ray powder diffraction method (XRPD). The climatic conditions of the area play an important role in the crystallization/recrystallization cycles of salts, which exerts additional pressure, by producing cracking, powdering and flaking, in addition to pulverization of the pictorial layers. The results showed that sodium chloride (halite, NaCl) is the predominant salt species affecting in the site. Furthermore, other salt minerals, such as sylvite (KCl), niter (KNO3), natron (Na2CO3·10H2O), thenardite (Na2SO4), gypsum (CaSO4·2H2O), anhydrite (CaSO4) and bassanite (CaSO4·0.5H2O) were also found. The obtained results allowed us to determine the main deterioration factors and may be used when applying a conservation plan

NEUTRALIZATION OF DYEING INDUSTRY WASTEWATER AND SLUDGE BY FIXATION OF POLLUTANTS IN VERY HIGH QUALITY HEU-TYPE ZEOLITIC TUFF

Treatment of dyeing industry wastewater of pH 7.5 with very high quality zeolitic tuff and coagulants, resulted in clear water of pH 7.2, free of odours and improved quality characteristics (colour, suspended particles, COD: Chemical Oxygen Demand, P2O5, NO3-, Cr) by 74 to 98%. The very high quality zeolitic tuff is 3 to 60% more effective than the coagulants, concerning COD, Cr and NO3-. The treatments produced sludge (using coagulants) and zeo-sludge (using very high quality zeolitic tuff and coagulants). The zeo-sludge is odourless and cohesive. The leaching by deionised water of sludge reached values up to 100% for the quality characteristics, while that of the zeo-sludge reached significantly lower values (only up to 18%). The chemical composition of the seepage water from the zeo-sludge proved the fixation of pollutants, such as NO3- and Cr by the very high quality zeolitic tuff

Modulation of the Release of a Non-Interacting Low Solubility Drug from Chitosan Pellets Using Different Pellet Size, Composition and Numerical Optimization

Two size classes of piroxicam (PXC) pellets (mini (380–550 μm) and conventional (700–1200 μm)) were prepared using extrusion/spheronization and medium viscosity chitosan (CHS). Mixture experimental design and numerical optimization were applied to distinguish formulations producing high sphericity pellets with fast or extended release. High CHS content required greater wetting liquid volume for pellet formation and the diameter decreased linearly with volume. Sphericity increased with CHS for low-to-medium drug content. Application of PXRD showed that the drug was a mixture of form II and I. Crystallinity decreased due to processing and was significant at 5% drug content. Raman spectroscopy showed no interactions. At pH 1.2, the dissolved CHS increased ‘apparent’ drug solubility up to 0.24 mg/mL while, at pH 5.6, the suspended CHS increased ‘apparent’ solubility to 0.16 mg/mL. Release at pH 1.2 was fast for formulations with intermediate CHS and drug levels. At pH 5.6, conventional pellets showed incomplete release while mini pellets with a CHS/drug ratio ≥2 and up to 21.25% drug, showed an extended release that was completed within 8 h. Numerical optimization provided optimal formulations for fast release at pH 1.2 with drug levels up to 40% as well as for extended release formulations with drug levels of 5% and 10%. The Weibull model described the release kinetics indicating complex or combined release (parameter ‘b’ > 0.75) for release at pH 1.2, and normal diffusion for the mini pellets at pH 5.6 (‘b’ from 0.63 to 0.73). The above results were attributed mainly to the different pellet sizes and the extensive dissolution/erosion of the gel matrix was observed at pH 1.2 but not at pH 5.6

THE INFLUENCE OF SANDBLASTING AND AGING ON Y-TZP CERAMIC DURING STATIC AND DYNAMIC LOADING

The purpose of this in vitro study was to investigate the mechanical response of zirconia ceramic during torsional, bending and vibrational loading, before and after aging and surface treatments. Three types of loading where imposed upon zirconia specimens, torsion, bending and vibration. The effects of aging, sandblasting and both on the shear modulus, Young's modulus, Poisson's ratio, storage modulus, loss modulus and tanδ were investigated, while surface characterization was performed through Scanning Electron Microscopy (SEM) and X-Ray Diffraction Analysis (XRD). Sandblasting as well as the aging environment caused a raise of zirconia's shear modulus, young's modulus and storage modulus. The most prominent increase, in these parameters was observed when both treatments where combined. Under the limitations of this in-vitro study it can be concluded that the proposed sandblasting and aging procedures do not impair the mechanical properties of zirconia ceramics, as long as the amount of monoclinic zirconia content is kept under low values, capable to induce the transformation toughening mechanism

Petrography and provenance of floor sediments from the Loutra Almopias Cave (Pella, Macedonia, Greece)

Thirty seven floor sediment samples of Upper Pleistocene age from the Loutra Almopias Cave were collected from different beds and stratigraphic columns on the basis of their induration grade, grain distribution, and paleontological findings. Channel facies make up the bulk of the clastic sediments found in the cave passages. Slackwater facies compose the final layer of all the stratigraphic sections of the examined cave. The floor sediments are mineralogically immature, since they contain many ferromagnesian minerals, feldspars (especially plagioclase) and quartz. The extensive presence of silicate minerals means that the phyllites, gneisses, schists, ophiolitic rocks and the clastic Mariam Formation of the Almopia Zone are the main detrital load source, along with the flysch of the neighboring Pelagonian Zone. The presence of sand-sized grains, pebbles and cobbles of dolomitic or calcitic composition also designates the carbonate rocks of the Almopia and Pelagonian Zones as primary sources. The dolomite and calcite content of secondary chemical origin in the cave sediments is very limited. Kutnohorite, isomorphous with dolomite, was found for first time in a Greek cave. The provenance of the sediments is mixed; they are composed mainly of the weathering materials of the Alpine metamorphic basement and the carbonate rocks outcropping adjacent to the cave. The sediments were transported and deposited inside the cave, after rapid weathering and erosion of the surrounding rocks, under a tectonically active regime. The mineralogical variation in the stratigraphic columns demonstrates variations in the clastic load, due to the different weathering intensity periods. Most of the sediments are fluvial deposits, and one is considered a glacial deposit. Fossils of Lepus timidus (mountain hare) found within the cave represent the southernmost record of this species in Europe. Its presence signifies a cool phase at the end of the last glacial period before the onset of the warm Holocene Epoch