The Journal of Middle East and North Africa Sciences

5-10

Authors: Jiang Chun-Xuan

Using Jiang function, we prove Jiang prime -tuple theorem, and prove that the Hardy-Littlewood prime -tuple conjecture is false. Jiang prime -tuple theorem can replace the Hardy-Littlewood prime -tuple conjecture.

17-21

Authors: Abdalla M. Abdalla Mustafa; Mohamed El Mukhtar A. Aziz

The use of hydroquinone is forbidden as it is potentially carcinogenic and skin and respiratory irritant, nevertheless, it is still the most conventional and widely used in skin- lightening creams. In this study, thirty samples of Skin-lightening creams, local and imported, were analyzed for total hydroquinone by using high-performance liquid chromatography (HPLC). The concentration of hydroquinone ranged from 0.00% to 5.75 % and from 0.00% to 3.21% for local and imported creams, respectively. However, Fair and Lovely's cream ranged from 0.47% to 4.76% respectively. The use of such creams may lead to health hazards. Therefore, it is recommended that all skin-lightening creams should be checked for hydroquinone levels before marketing.