We describe the use of degree of polarization to discriminate unscattered and weakly scattered light from multiply scattered light in an optically turbid material. We use spatially resolved measurements of the degree of polarization to compare how well linearly and circularly polarized light survives in a sample. Experiments were performed on common tissue phantoms consisting of polystyrene and Intralipid microsphere suspensions and on adipose and arterial tissue. The results indicate that polarization is maintained even after unpolarized irradiance through each sample has been extinguished by several orders of magnitude. The results also show that polarized light propagation in common tissue phantoms is distinctly different from polarized light propagation in the two tissues investigated. Further, these experiments illustrate when polarization is an effective discrimination criterion and when it is not. The potential of a polarization-based discrimination scheme to image through the biological and nonbiological samples investigated here is also discussed.

No abstract

Transparent face masks are the ultimate solution for improving communication during pandemic times while at the same time slowing the spread of pathogens. Here, we demonstrate an easily scalable process consisting of directly electrospinning polyamide nanofibers onto a mechanical stable substrate made of poly(lactic acid) by a needleless setup for the production of transparent filter material. Filtration tests against NaCl and fructose aerosols and pressure drop tests were performed and compared with the European standard for medical face masks (EN 14683:2019) and the Swiss rule for community masks (SNR 30000:2021). The filter showed outstanding transparency (∼70% transmittance in the visible-light range), 89% filtration efficiency against PM 1.0 , and a pressure drop of 6.5 Pa/cm 2 .

Neonatal death represents a major burden in Sub-Saharan Africa (SSA), where the main conditions triggering mortality, such as prematurity, labor complications, infections, and respiratory distress syndrome, are frequently worsened by hypothermia, which dramatically scales up the risk of death. In SSA, the lack of awareness on the procedures to prevent hypothermia and the shortage of essential infant devices to treat it are hampering the reduction of neonatal deaths associated to hypothermia. Here, we offer a snapshot on the current available medical solutions to prevent and treat hypothermia in SSA, with a focus on Kenya. We aim to provide a picture that underlines the essential need for infant incubators in SSA. Specifically, given the inappropriateness of the incubators currently on the market, we point out the need for reinterpretation of research in the field, calling for technology-based solutions tailored to the SSA context, the need, and the end-user.

The implementation of non-user-centered design is sometimes effective for traditionally mass-produced items; however, these methods do not take into account local needs, resources, and cultures, and the history of individual people and communities in low- and middle-income countries (LMIC). This neglect leads to “specialized” solutions based on a non-representative portion of high-income users, rather than the larger population of potential users, and results in devices that are alienated from the target community. In consequence, the resulting products do not work properly, nor do they have the intended impact. As an example, even if they do work at first, the implementation and maintenance effort and costs are usually so high that they rapidly fall into disuse. This chapter highlights examples of innovative practices of assistive technology based on users’ priorities, which are culturally appropriate and sustainable. The chapter also reviews the shortfalls of well-intentioned “solutions” that fail when they are implemented in the intended population due to the lack of a proper understanding of local context.