This latter approach pinpoints that for the establishment of complex multigene networks, several non-interacting switches or relais are needed. Progress has been made in the creation of independent gene regulation for mammalian systems. The combination of different systems within single cells or animals would allow to differentially control distinct circuits. As exemplified by this study the lentiviral transduction of a synthetic positive feedback circuit proves useful. Exploiting this tool for transduction of independently regulated synthetic modules will allow to reliably install more complex networks in mammalian cells including primary cells. Thereby, it provides an important step to synthetically modify these systems for systems biology approaches. Cervical length has been extensively studied as a predictive tool to Octinoxate identify women at high risk of preterm l-Chicoric-acid delivery in both singleton and multiple pregnancies. The inverse relationship between cervical length and preterm delivery is well documented. Uncontrolled studies first suggested that cervical length in women with multiple pregnancy was shorter than singleton pregnancies. A small controlled study showed that twin cervices were 5 mm shorter and triplets 10mm shorter at 23�C24 weeks, this disparity increasing with gestational age. Nevertheless, when predicting preterm delivery in twin pregnancies, a higher cervical length cut-off than in singletons has been recommended because of the greater prevalence of preterm delivery. Thus, a cut-off of 25mm achieves a sensitivity of 80% to predict preterm delivery #30 weeks gestation, which equates to the sensitivity seen with a cervical length #15mm in singletons. Although the mechanism of preterm labour and premature cervical maturation in multiples is not well understood, it is widely attributed to increased uterine volume and myometrial stretch leading to premature cervical ripening and ultimately preterm delivery.This difference may be attributed to a greater degree of polyhydramnios and uterine overdistension in our study group compared to Hershkowitz et al��s cohort of singleton pregnancies where the mean AFI was only 28cm.