Abstract Background The diffusion and reaction of the transmitter acetylcholine in neuromuscular junctions and the diffusion and binding of Ca2+ in the dyadic clefts of ventricular myocytes have been extensively modeled by Monte Carlo simulations and by finite-difference and finite-element solutions. However, an analytical solution that can serve as a benchmark for testing these numerical methods has been lacking. Result Here we present an analytical solution to a model for the diffusion and reaction of acetylcholine in a neuromuscular junction and for the diffusion and binding of Ca2+ in a dyadic cleft. Our model is similar to those previously solved numerically and our results are also qualitatively similar. Conclusion The analytical solution provides a unique benchmark for testing numerical methods and potentially provides a new avenue for modeling biochemical transport.

Researchers developed a method called fast Fourier transform (FFT)-based modeling of atomistic protein–protein interactions applied to cross second virial coefficient B23(FMAPB23) to characterize protein kinase A (PKA) subunits as macromolecular regulators of PKA RIα liquid-liquid phase separation. The cross second virial coefficient B23 was calculated for Mg2+-bound PKAcat [denoted as PKAcat(Mg2+)] and cAMP-bound RIα [denoted as RIa(cAMP)]. Five structures for the first molecule were taken from PDB: 6NO7 chains E and G, 3O7L chain B, and 4NTT chains A and B, while two structures for the second molecule were taken from 4MX3 chains A and B. The results from the total of ten runs were used to calculate a mean value and a standard error of the mean.

The internal dynamics of proteins inside of cells may be affected by the crowded intracellular environments. Here, we test a novel approach to simulations of crowding, in which simulations in the absence of crowders are postprocessed to predict crowding effects, against the direct approach of simulations in the presence of crowders. The effects of crowding on the flap dynamics of HIV-1 protease predicted by the postprocessing approach are found to agree well with those calculated by the direct approach. The postprocessing approach presents distinct advantages over the direct approach in terms of accuracy and speed and is expected to have broad impact on atomistic simulations of macromolecular crowding.

BACKGROUND: The importance of breastfeeding in low- and middle- income countries is well recognized, yet the importance of postnatal mental health on breastfeeding practices and beliefs in these settings has been understudied. This study investigates the associations between maternal mental health problems, breastfeeding beliefs and breastfeeding practices in rural China. METHODS: Cross-sectional data were collected in November and December 2019 from 742 mothers of infants under 6 months old in rural Sichuan Province, China. Maternal mental health (depression, anxiety, and stress symptoms) was assessed using the Depression, Anxiety, and Stress Scale (short form). Breastfeeding beliefs were assessed using the Iowa Infant Feeding Attitude Scale and Breastfeeding Self-Efficacy Scale (short form). Breastfeeding practices were assessed through a 24-h dietary recall questionnaire. Ordinary least squares regression, multiple logistic regression and heterogeneous effects analyses were used to identify associations between symptoms of mental health problems and breastfeeding outcomes. RESULTS: The average age of sample infants was 2.7 months. Among mothers, 13% showed symptoms of depression, 16% anxiety, and 9% stress. The prevalence of exclusive breastfeeding in the previous 24 h was 38.0%. Depression symptoms were significantly associated with breastfeeding attitude (𝛽= - 1.11, 95% CI: - 2.07, - 0.14) and breastfeeding self-efficacy (𝛽= - 3.19, 95% CI: - 4.93, - 1.45). Anxiety and stress symptoms were significantly associated with breastfeeding self-efficacy (𝛽= - 1.81, 95% CI: - 3.43, - 0.18 and 𝛽 = - 2.88, 95% CI: - 4.98, - 0.78, respectively). There were no significant associations between symptoms of mental health problems and exclusive breastfeeding. The heterogeneous effects analyses revealed that less educated mothers with symptoms of stress had lower odds of exclusive breastfeeding than educated mothers without symptoms of stress (OR: 0.53, 95% CI: 0.25,1.10). Mothers of younger infants had higher odds of exclusive breastfeeding than the mother of older infants, regardless of depression, anxiety, or stress symptoms. CONCLUSION: Symptoms of maternal mental health problems are significantly associated with breastfeeding attitude and self-efficacy; however, these symptoms are not associated with breastfeeding practices. Maternal educational level and infant age may play a role in mothers breastfeeding practices. To improve breastfeeding practices, interventions should employ a multi-dimensional approach that focuses on improving maternal mental well-being and considers demographic characteristics.