Interaction of the p53-regulated protein Gadd45 with proliferating cell nuclear antigen

GADD45 is a ubiquitously expressed mammalian gene that is induced by DNA damage and certain other stresses. Like another p53-regulated gene, p21WAF1/CIP1, whose product binds to cyclin-dependent kinases (Cdk's) and proliferating cell nuclear antigen (PCNA), GADD45 has been associated with growth suppression. Gadd45 was found to bind to PCNA, a normal component of Cdk complexes and a protein involved in DNA replication and repair. Gadd45 stimulated DNA excision repair in vitro and inhibited entry of cells into S phase. These results establish GADD45 as a link between the p53-dependent cell cycle checkpoint and DNA repair.     

Assessing the long-term effect of a surface penetrating sealant

Small defects are commonly found on the surfaces of composite restorations--especially in stress-bearing areas. Sealant application may reduce the wear rates of these restorations. This five-year study assesses the effect of sealant application on interfacial staining, clinical wear, marginal integrity and surface texture.     

The effect of furosemide on serum prolactin levels in the postpartum period

Furosemide, in combination with breast binding and milk fluid restriction, seems to inhibit postpartum lactation effectively, but has no effect in reducing serum prolactin levels. Inhibition of milk secretion must therefore be mediated by other mechanisms.     

Production of titania nanoparticles by a green process route

The manufacture of heterogeneous catalysts and catalyst supports produces substantial amounts of nitrate containing aqueous effluent. The use of nitrate free precursors and an environmentally friendly process would change the manufacture so that the entire process of catalyst synthesis and use can be considered green. In this work the precipitation of titania acetylacetonate nanoparticles for use as catalytic supports using a supercritical carbon dioxide anti-solvent process was investigated over a range of conditions. The effects of 1) pressure, 2) temperature, 3) solution flowrate, 4) solution concentration of TiO(acac)₂ in methanol, 5) nozzle diameter and 6) CO₂/methanol flow ratio on the mean particle size and morphology were studied. Particle sizes between 27 and 78 nm were obtained and were generally string and branch-like with an amorphous nature. Pressure and temperature had little effect on the mean particle size. A decrease in the velocity of the solution flow rate led to an increase in mean particle size and to particles that exhibited greater interconnectivity. It was also observed that an increase in concentration of TiO(acac)₂ in methanol led to an increase in mean particle size. The process shows promise for the production of catalysts by an environmentally acceptable route.     

Electron and photon emission accompanying the abrasion of MgO with diamond

We report simultaneous, time-resolved measurements of photon emission, electron emission, and frictional force during the abrasion of single crystal MgO with a diamond stylus in vacuum. We present evidence for the luminescence being primarily due to deformation and the electron emission being primarily due to fracture. Time-resolved measurements of all three signals show strong fluctuations which reflect stick-slip-like behavior. These measurements indicate enhanced deformation activity at the beginning of a stick event, with predominant fracture activity beginning some milliseconds later. These emissions provide insight into the processes responsible for catastrophic failure of ceramics in wear applications.     

Dynamic tribological probes: particle emission andtransient electrical measurements

We describe two novel, dynamic probes of fracture, wear, anddeformation during tribological loading that provide insight intoenergy dissipation mechanisms associated with fracture, flow, andadhesive detachment. These include applications of particleemission (fracto-emission) measurements and transient currentmeasurements to the abrasive wear of insulatingsubstrates. We illustrate the use of these probes during abrasivewear on single-crystal MgO by diamond and tungsten carbide. Wealso describe the signals produced when an oxidized aluminum tipis drawn across polymer substrates coated with perfluoropolyetherlubricants.     

Free vibration of a class of solids with cavities

The Ritz method is used to obtain an eigenvalue equation for the free vibration of a class of solids. Each solid is modelled by means of a segment which is described in terms of Cartesian coordinates and is bounded by the yz, zx and xy orthogonal coordinate planes as well as by two curved surfaces which are defined by polynomial expressions in the coordinates x, y and z. Simple algebraic polynomials which satisfy the boundary conditions at the five surfaces of the segment are used as trial functions. By exploiting symmetry, the range of problems which can be treated is substantially broadened and includes a variety of problems of significant interest in structural analysis, such as thick or very thick shells with various shaped cavities. In order to demonstrate the accuracy of the approach, natural frequencies are given for a sphere with a spherical cavity (a thick spherical shell) as calculated by using the present analysis and by using an exact formulation. The versatility of the approach is then demonstrated by the treatment of several other hollow solids of differing geometry, including a thick cylinder with end plates, a cubic box, a cube with a spherical cavity and a cylinder with a conical inclusion.