The metalloenzyme nitrogenase is utilized by microbial diazotrophs to accomplish the majority of biological nitrogen fixation. Many different forms of the enzyme nitrogenase are known to exist. They are categorized by the type of metal cluster providing the N2-binding site, which is also the active site of the enzyme. The nitrogenase best-characterized to date has an active site with the compos...

in this paper, two new hamilton operators are defined and the algebra of dual split quaternions isdeveloped using these operators. it is shown that finite screw motions in minkowski 3-space can be expressedby dual-number ( 3×3 ) matrices in dual lorentzian space. moreover, by means of hamilton operators, screwmotion is obtained in 3-dimensional minkowski space 3r1

Background: Minoxidil is currently an approved treatment for androgenetic alopecia. Topical tretinoin can enhance skin absorption of minoxidil. Objective: This study has been done in order to determine the efficacy and safety of the solution of 0.5% minoxidil+0.05% tretinoin compared to 2% minoxidil in androgenetic alopecia in men. Patients and Methods: In a randomized, double-blind, parallel-g...