La(0.7)Sr(0.3)MnO3 nanoparticles based ultra-high sensitive ammonia chemical sensor.

A facile, reliable, reproducible and ultra-high sensitive aqueous ammonia chemical sensor has been fabricated based on the utilization of La(0.7)Sr(0.3)MnO3 nanoparticles (LSMO NPs), as efficient electron mediators, and reported in this paper. The LSMO NPs were prepared by hydrothermal protocol followed by the annealing process and characterized in detail in terms of their mophological, structural and compositional properties. The I-V technique based aqueous ammonia sensor exhibits an ultra-high sensitivity of 494.68 +/- 0.01 microA cm(-2)mM(-1) and very low-detection limit of 0.2 microM with a response time less than 10 s. To the best of our knowledge, this is the first report in which LSMO is used as an efficient electron mediator for the fabrication of aqueous ammonia chemical sensor. Moreover, by comparing the literature, it is confirmed that the fabricated sensor exhibits highest sensitivity towards the detection of aqueous ammonia. This LSMO nanomaterial based research broadens the range of efficient electron mediators utilized for the fabrication of ultra-high sensitive chemical sensors.

The effect of eugenol-containing temporary cement on the bond strength of two resin composite core materials to dentin.

PURPOSE: This study investigated the effect of eugenol-containing temporary cement on the bond strength of two resin composite core materials (FluoroCore and Ti-Core) to dentin. MATERIALS AND METHODS: Dentin was exposed in three groups of extracted teeth (20 specimens each). In group one, dentin was covered with eugenol-containing temporary cement; the second group was covered with eugenol-free temporary cement; and the third group was left uncovered and served as a control group. All specimens were stored for 1 week at 37 degrees C and 100% humidity. The dentin surfaces were cleaned and treated using the GLUMA adhesive system, followed by placement of composite core build-ups. Debonding of the core material was accomplished using the Accuforce Elite test system. RESULTS: There was a significant reduction in bond strength for the specimens covered with eugenol temporary cement (p < .0001), but no significant difference was found between the control group and the group treated with eugenol-free temporary cement. Bond strength of the Ti-Core material to dentin was significantly higher than that of FluoroCore (p < .0001). CONCLUSION: Pretreatment of the dentin with eugenol-based temporary cement adversely affects the bond strength of resin composite core material to dentin.

Normal values of ocular protrusion in Saudi Arabian male children.

The extent of ocular protrusion from the orbit is an important sign in the diagnosis and management of ocular and orbital diseases. Ocular protrusion is dependent, among other factors, on ethnic origin, age, gender, high refractive error, axial length, inter outer orbital distance (IOOD), and interpupillary distance (IPD). The purpose of this study was to provide normal absolute and relative ocular protrusion values for Saudi Arabian male children of Arab origin and to furnish regression equations relating ocular protrusion to age, IOOD, and IPD. A cross-sectional study was designed and ocular protrusion and IOOD were measured using a Hertel prism exophthalmometer. The IPD was measured by using a corneal reflection pupillometer. The data were analyzed using t-test and analysis of variance tests. The average absolute ocular protrusion of the right and left eye was 15.4 mm +/- 1.6 and 15.2 mm +/- 1.6, respectively. The maximum difference in protrusion between the eyes was 2.0 mm. Saudi Arabian male children of Arab origin who have ocular protrusion values outside the 95% confidence intervals should be advised to undergo additional diagnostic tests. A relative ocular protrusion value greater than 2.0 mm may be indicative of unilateral proptosis among these subjects. On the average, Arab children have more ocular protrusion than Caucasians but less than Chinese children.