Oligorotaxane radicals under orders

A strategy for creating foldameric oligorotaxanes composed of only positively charged components is reported. Threadlike components-namely oligoviologens-in which different numbers of 4,4'-bipyridinium (BIPY(2+)) subunits are linked by p-xylylene bridges, are shown to be capable of being threaded by cyclobis(paraquat-p-phenylene) (CBPQT(4+)) rings following the introduction of radical-pairing interactions under reducing conditions. UV/vis/NIR spectroscopic and electrochemical investigations suggest that the reduced oligopseudorotaxanes fold into highly ordered secondary structures as a result of the formation of BIPY(\u2022+) radical cation pairs. Furthermore, by installing bulky stoppers at each end of the oligopseudorotaxanes by means of Cu-free alkyne-azide cycloadditions, their analogous oligorotaxanes, which retain the same stoichiometries as their progenitors, can be prepared. Solution-state studies of the oligorotaxanes indicate that their mechanically interlocked structures lead to the enforced interactions between the dumbbell and ring components, allowing them to fold (contract) in their reduced states and unfold (expand) in their fully oxidized states as a result of Coulombic repulsions. This electrochemically controlled reversible folding and unfolding process, during which the oligorotaxanes experience length contractions and expansions, is reminiscent of the mechanisms of actuation associated with muscle fibers

Birth outcomes by type of attendance at antenatal education: An observational study

Background: Antenatal education aims to prepare expectant parents for pregnancy, birth, and parenthood. Studies have reported antenatal education teaching breathing and relaxation methods for pain relief, termed psychoprophylaxis, is associated with reduction in caesarean section rates compared with general birth and parenting classes. Given the rising rates of caesarean section, we aimed to determine whether there was a difference in mode of birth in women based on the type of antenatal education attended. Materials and methods: A cross-sectional antenatal survey of nulliparous women ≥28 weeks gestation with a singleton pregnancy was conducted in two maternity hospitals in Sydney, Australia in 2018. Women were asked what type of antenatal education they attended and sent a follow-up survey post-birth. Hospital birth data were also obtained. Education was classified into four groups: psychoprophylaxis, birth and parenting, other, or none. Results: Five hundred and five women with birth data were included. A higher proportion of women who attended psychoprophylaxis education had a vaginal birth (instrumental/spontaneous) (79%) compared with women who attended birth and parenting, other or no education (69%, 67%, 60%, respectively P = 0.045). After adjusting for maternal characteristics, birth and hospital factors, the association was attenuated (odds ratio 2.03; 95% CI 0.93–4.43). Conclusions: Women who attended psychoprophylaxis couple-based education had a trend toward higher rates of vaginal birth. Randomised trials comparing different types of antenatal education are required to determine whether psychoprophylaxis education can reduce caesarean section rates and improve other birth outcomes

Maternal first trimester serum levels of free-beta human chorionic gonadotropin and male genital

Are maternal first trimester levels of serum free-beta hCG associated with the development of hypospadias or undescended testis (UDT) in boys? Overall, first trimester maternal levels of serum free-beta hCG are not associated with hypospadias or UDT. However, elevated levels were found in severe phenotypes (proximal hypospadias and bilateral UDT) suggesting an altered pathway of hormonal release in early pregnancy

Impact of the assimilation of ozone from the Tropospheric Emission Spectrometer on surface ozone across North America

We examine the impact of assimilating ozone observations from the Tropospheric Emission Spectrometer (TES) on North American surface ozone abundances in the GEOS-Chem model in August 2006. The assimilation reduces the negative bias in the modeled free tropospheric ozone, which enhances the ozone flux into the boundary layer. Surface ozone abundances increased by as much as 9 ppb in western North America and by less than 2 ppb in the southeast, resulting in a total background source of ozone of 20-40 ppb. The enhanced ozone in the model reduced the model bias with respect to surface ozone observations in the western USA, but exacerbated it in the east. This increase in the bias in the boundary layer in the east, despite the agreement between the assimilation and ozonesonde measurements in the free troposphere, suggests errors in the ozone sources or sinks or in boundary layer mixing in the model. © 2009