Search results for "visual_art"
showing 10 items of 2987 documents
Synthesis of isomorphous cobalt and nickel thiocyanate coordination compounds: Effect of metals on compound properties
2019
The reaction of 2-methylpiperazine with the thiocyanate ligand and two transition metals leads to the production of two new isomorphous [ML2SCN4] where L is the 2-methylpiperazine and [M =Co (1), and Ni (2)], presenting an octahedral configuration. These compounds were characterized by single crystal X-ray crystallography, TG-DTA analysis, as well as infrared and UV-Vis spectroscopy and TG-DTA. The magnetic and antibacterial properties were also determined. Through the link with N-H···S hydrogen bonds, a global 3D network was established. The studied compounds show the metal center’s impact leading to different properties. Indeed, the first compound shows high spin orbit coupling, whereas t…
Effect of Stacking Sequence and Sodium Bicarbonate Treatment on Quasi-Static and Dynamic Mechanical Properties of Flax/Jute Epoxy-Based Composites
2019
The present paper deals with the investigation of quasi-static and dynamic mechanical response of epoxy-based composites reinforced with flax and/or jute plain weave fabrics. In order to evaluate the influence of the stacking sequence, two monolithic laminates reinforced with flax or jute fibers and two hybrid flax/jute laminates were manufactured through the vacuum infusion technique. Furthermore, an eco-friendly and cost-effective surface treatment based on fiber soaking in a sodium bicarbonate solution was employed to improve the fiber-matrix adhesion. The mechanical characterization (by means of quasi-static flexural, dynamic mechanical thermal analysis and Charpy impact tests) allowed …
Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation
2019
Abstract In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent fu…
Brief History of Computer Art and New Media Art in Latvia
2011
The Soviet and particularly Latvian computer art is not a well-known topic of digital art history. This paper attempts to analyze this computer art in context of the 20th century art, considering the political circumstances in Soviet Union. At the turn of the 21st century after gaining the independence new media art examples and collaboration between scientists, computer scientists, software programmers and the artists are to be found in Latvia. Some recent media art events are mentioned from this viewpoint.
Micro-X-Ray Fluorescence and the Old Masters Non-destructive in situ characterisation of the varnish of historical Low Countries stringed musical ins…
2012
Applied Physics A, 107
Bond strength of cemented fiber posts to teeth with simulated internal root resorption
2020
Made available in DSpace on 2021-06-25T10:58:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Background: Teeth with internal root resorption (IRR) have guarded prognosis, considering that IRR defect could influence on the post bond strength. The aim of this study was to evaluate the bond strength and the bond interface between different glass fiber-reinforced posts (FRP) after cementation in teeth with simulated internal root resorption (IRR). Material and Methods: Forty-five (45) human premolar roots with simulated IRR were embedded in acrylic resin blocks and cross-sectioned into two segments, enabling them to be re-approximated by screws. Intracanal medication was inserte…
The impact of head and neck radiotherapy on the dentine-enamel junction: a systematic review
2019
Background Radiotherapy is widely used in contemporary head and neck cancer treatment protocols. The ability of head and neck radiotherapy (HNRT) to cause direct radiogenic destruction to the teeth is one of the most controversial topics in the field of oral oncology. Therefore, this systematic review aimed to investigate ionising radiation as an independent factor for physical and chemical changes on the dentine-enamel junction (DEJ), a pivotal dental topography for the onset and progression of radiation-related caries (RRC) and enamel delamination. Material and Methods Systematic searches were conducted on three databases: Scopus, MEDLINE (Via PubMed) and Embase (Elsevier). Laboratory stu…
Advances in surfaces and osseointegration in implantology. Biomimetic surfaces
2015
The present work is a revision of the processes occurring in osseointegration of titanium dental implants according to different types of surfaces -namely, polished surfaces, rough surfaces obtained from subtraction methods, as well as the new hydroxyapatite biomimetic surfaces obtained from thermochemical processes. Hydroxyapatite’s high plasma-projection temperatures have proven to prevent the formation of crystalline apatite on the titanium dental implant, but lead to the formation of amorphous calcium phosphate (i.e., with no crystal structure) instead. This layer produce some osseointegration yet the calcium phosphate layer will eventually dissolve and leave a gap between the bone and …
Analysis of a soluble lipid-protein complex carrying endogenous 11-cis retinaldehyde from bovine retinal pigment epithelium.
1989
A soluble lipid-protein complex in bovine retinal pigment epithelium is shown to carry endogenous 11-cis retinaldehyde, in the extent of 15% of the total 11-cis retinaldehyde found in this tissue. The complex, analyzed with respect to its chemical composition, exhibits a lipid composition close resembling the lipid composition of the rod outer segment membrane; the SDS-PAGE evidences the presence of a number of protein bands, two of which of 34 and 27 kDa appear glycoproteins. Finally, the lipid-protein complex exhibits a discrete level of a Cathepsin D-like protease activity. From the above, the possibility is discussed that the soluble lipid-protein complex could represent some phagolysos…
Inorganic Mercury Sequestration by a Poly(ethylene imine) Dendrimer in Aqueous Solution
2015
The interaction of the G-2 poly(ethylene imine) dendrimer L, derived from ammonia as initiating core, with Hg(II) and HgCl4 2− was studied in aqueous solution by means of potentiometric (pH-metric) measurements. Speciation of these complex systems showed that L is able to form a wide variety of complexes including 1:1, 2:1, 3:1 and 3:2 metal-to-ligand species, of different protonation states, as well as the anion complexes ((H7L)HgCl4) 5+ and ((H8L)HgCl4) 6+ . The stability of the metal complexes is very high, making L an excellent sequestering agent for Hg(II), over a large pH range, and a promising ligand for the preparation of functionalized activated carbons to be employed in the remedi…