Safe Delivery application with facilitation increases knowledge and confidence of obstetric and neonatal care among frontline health workers in India.

Background: Digital learning tools have proliferated among healthcare workers in India. Evidence of their effectiveness is however minimal. We sought to examine the impact of the Safe Delivery App (SDA) on knowledge and confidence among frontline health workers (HW) in India.

mHealth learning tool for skilled birth attendants: scaling the Safe Delivery App in India.

Background: One of the main drivers of maternal and newborn mortality and morbidity in India is a lack of quality of care in health facilities. Inadequate competencies of health workers, insufficient quality of training and infrastructure, and the financial challenges of providing training across the country impede quality care provision. To this end, the Government of India began exploring cost-effective tech and IT-based solutions to support existing quality improvement (QI) initiatives.

Limitations of the equivalent neutral polymer assumption for theories describing nanochannel-confined DNA.

The prevailing theories describing DNA confinement in a nanochannel are predicated on the assumption that wall-DNA electrostatic interactions are sufficiently short-ranged such that the problem can be mapped to an equivalent neutral polymer confined by hard walls with an appropriately reduced effective channel size. To determine when this hypothesis is valid, we leveraged a recently reported experimental data set for the fractional extension of DNA molecules in a 250-nm-wide poly(dimethyl siloxane) (PDMS) nanochannel with buffer ionic strengths between 0.075 and 48 mM.

Extension distribution for DNA confined in a nanochannel near the Odijk regime.

DNA confinement in a nanochannel typically is understood via mapping to the confinement of an equivalent neutral polymer by hard walls. This model has proven to be effective for confinement in relatively large channels where hairpin formation is frequent. An analysis of existing experimental data for Escherichia coli DNA extension in channels smaller than the persistence length, combined with an additional dataset for λ-DNA confined in a 34 nm wide channel, reveals a breakdown in this approach as the channel size approaches the Odijk regime of strong confinement.

Simulations corroborate telegraph model predictions for the extension distributions of nanochannel confined DNA.

Hairpins in the conformation of DNA confined in nanochannels close to their persistence length cause the distribution of their fractional extensions to be heavily left skewed. A recent theory rationalizes these skewed distributions using a correlated telegraph process, which can be solved exactly in the asymptotic limit of small but frequent hairpin formation. Pruned-enriched Rosenbluth method simulations of the fractional extension distribution for a channel-confined wormlike chain confirm the predictions of the telegraph model.

Measuring the wall depletion length of nanoconfined DNA.

Efforts to study the polymer physics of DNA confined in nanochannels have been stymied by a lack of consensus regarding its wall depletion length. We have measured this quantity in 38 nm wide, square silicon dioxide nanochannels for five different ionic strengths between 15 mM and 75 mM. Experiments used the Bionano Genomics Irys platform for massively parallel data acquisition, attenuating the effect of the sequence-dependent persistence length and finite-length effects by using nick-labeled genomic DNA with contour length separations of at least 30 m (88 325 base pairs) between nick pairs.

Evaluation of Blob Theory for the Diffusion of DNA in Nanochannels.

We have measured the diffusivity of λ-DNA molecules in approximately square nanochannels with effective sizes ranging from 117 nm to 260 nm at moderate ionic strength. The experimental results do not agree with the non-draining scaling predicted by blob theory. Rather, the data are consistent with the predictions of previous simulations of the Kirkwood diffusivity of a discrete wormlike chain model, without the need for any fitting parameters.

Effect of Surface Wettability on Crack Dynamics and Morphology of Colloidal Films.

The effect of surface wettability on the dynamics of crack formation and their characteristics are examined during the drying of aqueous colloidal droplets (1 μL volume) containing nanoparticles (53 nm mean particle diameter, 1 w/w %). Thin colloidal films, formed during drying, rupture as a result of the evaporation-induced capillary pressure and exhibit microscopic cracks. The crack initiation and propagation velocity as well as the number of cracks are experimentally evaluated for substrates of varying wettability and correlated to their wetting nature.