University of Jordan

About: University of Jordan is a education organization based out in Amman, Jordan. It is known for research contribution in the topics: Population & Health care. The organization has 7796 authors who have published 13764 publications receiving 213526 citations.

The effect of thermocycling on microleakage of several commercially available composite Class V restorations in vitro.

Abstract: Statement of the problem Microleakage is a major factor contributing to the occurrence of secondary carious lesions around composite restorations. Purpose of study This in vitro study investigated the effect of thermocycling on microleakage of several composite Class V restorations. Material and methods One hundred twenty molars were randomly distributed into 6 groups of 20 teeth. Class V preparations were made in the buccal and lingual surfaces of each tooth and restored in bulk by use of 6 composites (Arabesk, Silux-Plus, Solitaire 2, Durafill VS, Charisma, and Renew) according to the manufacturers' recommendations. The teeth were stored in distilled water at room temperature for 24 hours. The teeth in each group were divided randomly into 2 subgroups: (a) thermocycled for 500 cycles between 5° and 55°C with a dwell time of 30 seconds, (b) no thermocycling treatment. All restored teeth were immersed in 1% methylene blue dye for 4 hours and sectioned buccolingually with a diamond wheel. Dye penetration was scored by use of a stereomicroscope at original magnification ×4. The generalized linear models statistical analysis was used (α=.05). Results The preparation margins (enamel/dentin) and thermocycling had a significant effect on microleakage ( P =.0351, P P =.1689). Conclusions Thermocycling significantly increased the microleakage ( P P =.0351).

Fitted fractional reproducing kernel algorithm for the numerical solutions of ABC – Fractional Volterra integro-differential equations

Abstract: This paper focuses on providing a novel high-order algorithm for the numerical solutions of fractional order Volterra integro-differential equations using Atangana–Baleanu approach by employing the reproducing kernel approximation. For this purpose, we investigate couples of Hilbert spaces and kernel functions, as well as, the regularity properties of Atangana–Baleanu derivative, and utilize that the representation theorem of its solution. To remove the singularity in the kernel function, using new Atangana–Baleanu approach the main operator posses smoothing solution with a better regularity properties and the reproducing kernel algorithm is designed for the required equation. The convergence properties of the proposed algorithm are also studied which proves that the new strategy exhibits a high-order of convergence with decreasing error bound. Some numerical examples of single and system formulation illustrate the performance of the approach. Summary and some notes are also provided in the case of conclusion and highlight.

Evaluating greywater reuse potential for sustainable water resources management in Oman.

Abstract: This study aims to evaluate the potential of greywater availability in Muscat Governorate in the Sultanate of Oman, to establish a methodology for greywater quantity estimation, to test greywater quality in order to assess reuse potential, and to examine public acceptance for reuse.Total fresh water consumption and greywater generation from different household sources were measured by water meters in five selected households during summer and winter. Additionally, a survey was designed and conducted in five administrative areas of Muscat Governorate, with the objective of testing a methodology for estimating greywater generation potential in these areas. Collected data were compared with that used by the Ministry of Housing, Electricity and Water, Sultanate of Oman. The survey covered a total of 169 houses and 1,365 people. Greywater samples were collected and analyzed from showers, laundries, kitchens and sinks in some of these households to determine their water quality parameters. Statistical analysis results indicated that there is no significant variance in the total fresh water consumption between data used by the ministry and those measured and estimated during this study, highlighting the applicability of the tested method. The study concluded that the average per capita greywater generation rate is 151 Lpcd. Greywater production ranged from 80 to 83% of the total fresh water consumption and most of the greywater is generated from showers. Further, 55 to 57% of the greywater generated in a typical Omani household originated from the shower, 28 to 33% originated from the kitchen, 6 to 9% originated from laundry, and 5 to 7% originated from sink, which constitutes approximately 81% of the total fresh water consumption. The physical, chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids, inorganic constituents, total organic carbon, chemical and biochemical oxygen demands, total Coliforms and Escherichia Coliform bacteria. The public acceptance survey illustrated that approximately 76% of the respondents accepted the reuse of greywater for gardening, 53% for car washing and 66% for toilet flushing.

Nicotine content in tobacco used in hubble-bubble smoking.

Abstract: OBJECTIVES To determine the nicotine content of commonly used tobacco in hubble-bubble (HB) and compare it with that found in cigarettes. METHODS Analysis of nicotine content of 13 commercial brands of HB tobacco was carried out using gas chromatography over an 8 month period; November 2002 through to June 2003 at the Toxicology Laboratory, University of Jordan. RESULTS A wide variation in nicotine content in all brands was noticed with an average of 8.32 mg/g tobacco, range (1.8-41.3 mg/g). The average nicotine content in each HB head (20 gm) of unflavored tobacco was (713 mg/head) and flavored tobacco has (67 mg/head). One head of unflavored tobacco has nicotine equivalent to 70 regular cigarettes. The addition of adulterations; honey, glycerin and other flavors in the process of preparing the flavored (Muasel) tobacco contributes to lowering the nicotine content in each gram of flavored tobacco. Smoking one head of flavored (Mua'sel) tobacco which contains on average one third of nicotine presented in 20 cigarettes (204 mg/pack) usually resulted in a higher plasma nicotine level by 20%. CONCLUSIONS Hubble-bubble smokers are not at a lesser risk from smoking than cigarette smokers in relation to nicotine dependence. The inability of water to trap significant amounts of chemical substances present in tobacco (especially nicotine) and the danger which might result from the combustion of additives like; glycerin, honey and other flavors could be a very important factor to extrapolate the damage resulting from HB smoking.