Revealing pseudorotation and ring-opening reactions in colloidal organic molecules

Colloids have a rich history of being used as 'big atoms' mimicking real atoms to study crystallization, gelation and the glass transition of condensed matter. Emulating the dynamics of molecules, however, has remained elusive. Recent advances in colloid chemistry allow patchy particles to be synthesized with accurate control over shape, functionality and coordination number. Here, we show that colloidal alkanes, specifically colloidal cyclopentane, assembled from tetrameric patchy particles by critical Casimir forces undergo the same chemical transformations as their atomic counterparts, allowing their dynamics to be studied in real time. We directly observe transitions between chair and twist conformations in colloidal cyclopentane, and we elucidate the interplay of bond bending strain and entropy in the molecular transition states and ring-opening reactions. These results open the door to investigate complex molecular kinetics and molecular reactions in the high-temperature classical limit, in which the colloidal analogue becomes a good model.

ADVERSE CHILDHOOD EXPERIENCES ARE ASSOCIATED WITH FRAILTY IN OLD AGE

With an increasing life expectancy, frailty is becoming an important outcome reflecting lower chances of healthy ageing. However, research on long-term risk factors of frailty is lacking. We aimed to assess associations of adverse childhood experiences (ACE) with frailty trajectories at older age, and to examine whether this link can be broken by the person’s life course socioeconomic trajectory. Data was used of 13,283 women and 10,591 men aged 50 years and over included in the Survey of Health, Ageing, and Retirement in Europe, who were followed from 2004 to the latest wave. ACE (from 0 to 15 years) were measured with six indicators; not living with biological parents, death of parents, period of hunger, property taken away, adolescent parenthood, stillborn child in adolescence. Frailty was operationalized according to Fried’s phenotype, presenting either weakness, shrinking, exhaustion, slowness, or low activity. Confounder-adjusted multilevel logistic regression models were used to analyse associations of ACE with frailty trajectories. Risk of frailty increased through age and with ageing. ACE was associated with risk of frailty among women and men. Among men only, ACE was associated with an accelerated increase of the risk of frailty. For both sexes, the ACE and frailty association was not mediated by the person’s life course socioeconomic trajectory. Experiencing adverse events in childhood is linked with frailty at older age. Such an unfavourable start in life is not compensated by the person’s life course socioeconomic trajectory. Men’s frailty with ageing is more sensitive to ACE compared to women.

[Persistent cystitis in a male cat]

The case of a male cat with persistent cystitis is reported. Microscopy of the urine revealed the presence of eggs of Capillaria. The clinical picture and treatment are discussed.