INTRODUCTION The swim up and the density-gradient centrifugation are the two main techniques which are used to separate the viable motile sperm fraction in the assisted reproductive technology. However, there are several published studies about these methods, but there is no sufficient evidence for recommending the superiority of one of them. This study was designed to study the efficiency of t...

RNA polymerase II from larvae of the brine shrimp, Artemia salina, was highly purified by two cycles of DEAE-cellulose chromatography followed by centrifugation through discontinuous sucrose gradients. Gradient fractions were subjected to elctrophoresis is polyacrylamide gels containing sodium dodecyl sulfate. The subunit structure of RNA polymerase II was determined by quantitative comparison ...

Size and geometric control of nanomaterials are important to the discovery of intrinsic size/shape dependent properties and bottom up approaches for the fabrication of functional nanodevices. Two general strategies have been employed to create size-uniform nanocrystals. One method is direct particle size control during synthesis by adjusting growth parameters; 7–9] the other is post-synthesis s...