Stainless steel alloys containing 8% to 12% nickel and 17% to 22% chromium are generally used in orthodontic appliances. A major concern has been the performance of alloys in the environment in which they are intended to function in the oral cavity. Biodegradation and metal release increase the risk of hypersensitivity and cytotoxicity. This case report describes for the first time a CAD/CAM zi...

A new form of nanoporous material, metal intercalated covalent organic framework (MCOF) is proposed and its energy storage property revealed. Employing density functional and thermodynamical analysis, we find that stable, chemically active, porous materials could form by stacking covalent organic framework (COF) layers with metals as a gluing agent. Metal acts as active sites, while its aggrega...

A new porous metal-organic framework, PCN-20 with a twisted boracite net topology, was constructed based on a highly conjugated planar tricarboxylate ligand; PCN-20 possesses a large Langmuir surface area of over 4200 m(2)/g as well as demonstrates a high hydrogen uptake capacity of 6.2 wt % at 77 K and 50 bar.

Objectives: The present study evaluated the effect of bar and ball attachment designs on retention and stability of a mandibular overdenture supported by four implants. Methods: An edentulous mandibular acrylic resin model with four implants in the anterior part of the ridge (A, B, D and E) was fabricated. A metal framework simulating the overdenture was also fabricated. Totally, 30...

The so-called roll bar measurement uses a heavy metal material, optically thick to x-rays, to form a shadow of the x-ray origination spot. This spot is where an energetic electron beam interacts with a high Z target. The material (the “roll bar”) is slightly curved to avoid alignment problems. The roll bar is constructed and positioned so that the x-rays are shadowed in the horizontal and verti...

Multi-atmospheric pressure, pulsed electric discharge excited lasers require pre-ionization to produce spatially uniform glows. Many such systems use corona bars to produce ultraviolet (UV) and vacuum ultraviolet (VUV) light as photo-ionization sources for this purpose. Corona bars are transient surface discharges, typically in a cylindrical geometry, that sustain high electron temperatures and...

Anew set-up is proposed to perform high strain rate tension experiments on sheet metal using a compression Hopkinson bar system on the input side.With the help of a custommade load inversion device, the compression loading pulse is converted into tensile loading of the specimen boundary. A tensile output bar is used to measure the tensile force acting on the specimen boundaries. A high speed ca...

Hydrogen storage in MWNT was enhanced ®ia the catalytic acti®ity of NiMgO. The magnitude of the hydrogen to metal ratio for the MWNTrNiMgO system, combined with temperature programmed adsorption and desorption studies, showed hydrogen spillo®er from the catalyst to the carbon surface. Metal doping combined with temperature acti®ation studies showed that both nickel and magnesium are acti®e in t...

A Cu−carborane-based metal−organic framework (MOF), NU-135, which contains a quasi-spherical para-carborane moiety, has been synthesized and characterized. NU-135 exhibits a pore volume of 1.02 cm/g and a gravimetric BET surface area of ca. 2600 m/g, and thus represents the first highly porous carborane-based MOF. As a consequence of the unique geometry of the carborane unit, NU-135 has a very ...