Design and Implementation 4-Bit Quaternary MVL Arithmetic and Logic Unit

In the recent years, there were major importance to Multiple Valued Logic (MVL), where the most common reasons for considering the implementation of MVL circuits better then binary valued circuits are that reducing wiring congestion as compared to binary circuits, using a single conductor to transmit three or more discrete voltage or current values allows for greater information content per wire and the circuit cost models would be more economical. Therefore, in this paper the MVL concepts have been used to design 4-bit quaternary MVL Arithmetic and Logic Unit, which is considered a basic unit of a MVL microprocessor. It is the "heart" of a microprocessor and we could say that everything else in the microprocessor is there to support the ALU. The proposed Arithmetic and Logic Unit will do the operations as Addition, Subtraction, Maximum, Minimum and Invert. Simulation Program with Integrated Circuit Emphasis (SPICE) tool in Cadence simulator used in simulation the proposed Arithmetic and Logic Unit. The simulation results tells that the design is more efficient compared with the binary ALU and the circuit will be less area and less number of transistors

Clinical Evaluation of Pit and Fissure Sealants Placed by Undergraduate Dental Students in 5-15 Years-old Children in Iraq

Objective: To clinically evaluate the retention and marginal discoloration of pit and fissure sealants applied to primary and permanent teeth. Material and Methods: The study population encompassed of 5-15 years- old children. After consenting, a light-curing sealant was applied to etched pits and fissures of occlusal surfaces of selected sound teeth. The retention rate and marginal discoloration were assessed, 3 months after application of the sealants based on the criteria proposed by Simonsen’s criteria (total retention: score 0, partial loss: score 1, and total loss: score 2). Each tooth was considered as an independent sample during analysis. Results: The achieved sample size was 43 children aged 5-15 years (mean age=10.0 years). Therefore, data of 100 teeth from 43 children were used for the final analysis. The percentage of completely retained sealants (59%) was higher than the percentage of partially retained sealants (23%) and completely missing sealants (18%) after 3 months follow up. Out of 100 sealed teeth, 60% were either had marginal discoloration or completely missing. Using the Mann-Whitney test, there was a statistically significant difference (p<0.05) between primary and permanent teeth in terms of retention. However, there was no statistical difference (p>0.05) between upper and lower teeth in terms of retention. Conclusion: The success rate of fissure sealants after 3 months follow-up was satisfactory