227 research outputs found
The Bis(1,2,3,4-tetrahydroisoquinoline) Alkaloids Cepharanthine and Berbamine Are Ligands of SK Channels
peer reviewe
Solubility control of thin calcium-phosphate coating with rapid heating
http://jdr.iadrjournals.org/cgi/reprint/76/8/148
1-Nonyl-1H-benzimidazol-2(3H)-one
The crystal structure of the title compound, C16H24N2O, is built up from two fused six- and five-membered rings linked to C9H19 chains. The fused-ring system is essentially planar, the largest deviation from the mean plane being 0.009 (2) Å. The chain is nearly perpendicular to this plane [dihedral angle = 80.27 (17)°]. In the crystal, intermolecular N—H⋯O hydrogen bonds form dimers with an R
2
2(8) graph-set motif. These dimers are further connected through C—H⋯O hydrogen bonds, building sheets parallel to (100)
Effect of gluon-exchange pair-currents on the ratio G(E(P))/G(M(P))
The effect of one-gluon-exchange (OGE) pair-currents on the ratio for the proton is investigated within a nonrelativistic
constituent quark model (CQM) starting from nucleon wave
functions, but with relativistic corrections. We found that the OGE
pair-currents are important to reproduce well the ratio .
With the assumption that the OGE pair-currents are the driving mechanism for
the violation of the scaling law we give a prediction for the ratio of the neutron.Comment: 5 pages, 4 figure
Prodromes of Descriptive Geometry in the Traité de stéréotomie by Amédée François Frézier
X-ray fluorescence analysis of superalloy leach liquors using a thin-film technique
"The U.S. Bureau of Mines has developed a thin-film x-ray fluorescence technique to rapidly determine cu, ni, CO, fe, and cr in superalloy leach liquors. Total analysis time per sample was less than 15 min, as opposed to several hours for traditional wet chemical methods. Precision and accuracy were checked by replicate analyses of solutions similar in composition to leach liquors, whose analyte concentrations were well known. Coefficients of variation for all elements were found to be less than 2 pct. With the exception of the results for fe, all relative errors of estimation were also found to be less than 2 pct. Bulk liquids are not introduced into the spectrometer; thus, the potential for damage to the instrument by leakage of corrosive liquids is eliminated." - NIOSHTIC-2NIOSHTIC no. 1000725
Mechanical Properties of Dual-Cured Resin Luting Agents for Ceramic Restoration
Purpose: The aim of the present study was to evaluate the mechanical properties including surface hardness, flexural strength, and flexural modulus of two dual-cured resin luting agents (New Resin Cement [NRC] and Variolink II [VLII]) irradiated through four different thickness of leucite ceramics (0, 1, 2, and 3 mm) and their shear bond strength to zirconia ceramic (Cercon) using each ceramic primer. Materials and Methods: Knoop hardness was measured on a thin layer of resin luting agent on the ceramic surface. Three-point bending tests were performed after 24 h storage at 37°C. Two different-shaped zirconia ceramic specimens with or without sandblasting with alumina were treated with each primer. The specimens were then cemented together with each resin luting agent. Half of the specimens were stored in water at 37°C for 24 h and the other half were thermocycled 5,000 times. Results: VLII revealed statistically higher Knoop hardness and flexural modulus than NRC for each thickness of ceramic. No significant differences in flexural strength were observed between VLII and NRC for each ceramic spacer. Reduction of the mechanical properties with increase of ceramic thickness varied for each property. However, these properties were similar between the two materials. Blasting with alumina was significantly effective for increasing shear bond strength of both resin luting agents before and after thermal cycling. The use of New Ceramic Primer showed the highest shear bond strength and maintained bond durability after 5,000 thermocycles. Conclusion: Mechanical properties of NRC dual-cured resin luting agent appear adequate for ceramic restorations.This is an electronic version of an Article published in Journal of Prosthodontics 16(5): 370-376, 2007
Design and analysis of cross vaults along history
The history of cross vaults began almost 2,000 years ago with a widespread use during the Middle Ages and Renaissance, becoming nowadays one of the most diffused and fascinating structural typologies of the European building cultural heritage. However, conversely to the undeniable excellence achieved by the ancient masons, the structural behavior of these elements is still at the center of the scientific debate. In this regard, with the aim of reviewing the knowledge on this subject as a concise and valuable support for researchers involved in conservation of historical buildings, with a focus on design rules and structural analysis, the present study firstly introduces the cross vaults from a historical perspective, by describing the evolution of the main geometrical shapes together with basic practical rules used to size them. Then, the article deals with the subsequent advancements in structural analysis methods of vaults, until the development of modern limit analysis.This work was partially carried out under the program "Dipartimento di Protezione Civile - Consorzio RELUIS", signed on 2013-12-27.info:eu-repo/semantics/publishedVersio
La mecánica ilustrada en los ingenieros militares españoles. El proyecto de los almacenes de pólvora (1715-1798)
Tribology of Medical Devices
Importance of tribology in a number of medical devices and surgical instruments is reviewed, including artificial joints, artificial teeth, dental implants and orthodontic appliances, cardiovascular devices, contact lenses, artificial limbs and surgical instruments. The current focus and future developments of these medical devices are highlighted from a tribological point of view, together with the underlying mechanisms
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