Heavy metals accumulation in fruits and vegetables grown on sewage sludge and that of river water

In this study the crops cultivated on the application of sewage sludge were investigated. The crops grown included lady finger [okra], round gourd, smooth luffa, spinach, pumpkin, red pepper, green pepper and the fruits [pomegranate, mango, lemon, java plum, guava, banana, melon]. Results showed that sewage irrigation significantly increased total heavy metal contents in different organs [leaf, peel and pulp] of the crops in comparison to river water. The sewage water carried a very high load of Pb, Fe, Cu, Zn, Mg, Ca and other heavy elements. Maximum concentration in lady's fmger was for Mg followed by Zn, Cu, Ca, Fe, Pb and Co. There was significant increase in Mg concentration in leaf at 73.20 mg ke. Concentrations of Zn, Cu, Ca, Fe, Pb and Co were lower varying from 0.30 to 1.0 in leaf, 0.50 to 1.60 in peel and 0.70 to 1.70 in pulp. The accumulation of heavy metals by other vegetables was similar except spinach which showed high content of Fe at 39.0 mg kg-' in leaf. Plants fed on sewage water produced fruits showing heavy metals accumulation. It appeared that the metals accumulated and distributed between tissues in nearly the same proportion as in the vegetables. The river water fed vegetables and fruits, however, showed lesser accumulation of the heavy metals

Variations in powder/liquid ratio of a restorative and luting glass lonomer cement in dental clinics

A survey was conducted to ascertain the variations practiced in powder/liquid [P/L] ratio of Glass lonomer Cement [GIC] used as restorative and luting material in dental clinics of Karachi. It has been observed that in the use of GIC brands, 33% [Fuji 2] and 36% [Gold Label 2] of the dentists, did not follow the recommended P/L ratios for restorative purposes. Similarly, 67% [Fuji 1] and 29% [Gold Label 1] did not follow the recommended ratios for luting purposes. The wide variations practiced in P/L mixing ratios against the recommended ratio for restorative purpose [[tilde]1:2] and that for luting purpose [[tilde]1:1 to 2:1] may affect the performance characteristics of the material

Use of different light-curing units in setting of dental restorative materials

The resin based filling materials were introduced in dentistry at the end of the 1940s. Poor color stability, low stiffness, lack of adhesion to tooth structure were the major drawback of this class of restorative material. Polymerization shrinkage is one of the challenges wh1th needs improvement of this material to many methods were developed. Light curing units which were the major breakthrough and the energy efficiency of the different light sources have also been discussed

Development of glass-ionomer cements as dental restorative materials

Physico-chemical adhesion with tooth sabstance has necessitated the production of polyacrylic acid based cements such as glass-ionomer cements [GICs] as dental restorative material. These materials undergo specific adhesion with hydroxyapatite and have been proved to possess properties that are satisfactory for a variety of clinical applications. In order to improve toughness, speed of setting and ressitance to dehydration, hybird materials are incorporated in the formulations to achieve desired ambient polymerization. FTIR, IR and Raman spectroscopic techniques have been used for observing the physico-chemical changes involved in the setting process. Different glass ionomer cement formulations used for this purpose have been presented