This literature review investigates nursing interventions to reduce decibel levels in the neonatal intensive care unit (NICU). The secondary purpose of this review was to evaluate if the interventions to reduce noise in the NICU had different outcomes for normal weight premature infants and infants afflicted with neonatal abstinence syndrome. The data bases for completing this review were Google Scholar, the Cumulative Index to Nursing and Allied Health Literature (CINAHL Plus), PubMed, and Elton B. Stephens Co. (EBSCO). The key search words included ‘NICU and decibels', ‘reducing decibels', ‘neonatal abstinence syndrome' ‘decibels', ‘preterm infants' and 'normal weight preterm infant*'. The inclusion criteria were research articles from 2008 to 2020, articles with a focus on normal weight premature infants and normal weight infants determined to be addicted to a recreational or illicit substance after birth. The results yielded 8 articles meeting inclusion criteria and screened for relevance to the topic. Data indicated there is a need for further research into using multiple interventions. One intervention alone can currently not reduce decibel levels to the recommended level. Conclusions: Currently the research states private rooms reduce decibel levels the most out of the other intervention listed in the study. Further research with long-term neuro-cognitive data collection over a longer period of time and larger sample sizes is needed to evaluate the use of interventions to reduce high level, decibel noise found in the NICU.

Frequency selective surfaces (FSSs) provide a variety of spatial filtering functions, such as band-pass or band-stop properties in a radome or other multilayer structure. This filtering is typically achieved through closely-spaced periodic arrangements of metallic shapes on top of a dielectric substrate (or within a stack of dielectric materials). In most cases, the unit cell size, its shape, the substrate parameters, and the inter-element spacing collectively impact the response of the FSS. Expanding this design space to include reconfigurable FSSs provides opportunities for applications requiring frequency agility and/or other properties. Tuning can also enable operation over a potentially wider range of frequencies and can in some cases be used as a loading mechanism or quasi-ground plane. Many technologies have been considered for this type of agility (RF MEMS, PIN diodes, etc.). This includes the recent use of microfluidics and dispersions of nanoparticles, or fluids with controllable dielectrics, which have entered the design space of numerous other EM applications including stub-tuners, antennas, and filters. In this work they provide a material based approach to reconfiguring an FSS. An FSS based on a four-arm spiral with tunable band-stop characteristics is presented in this work. A thin colloidal dispersion above each element provides this tuning capability. The radial expansion and contraction of this dispersion, as well as the variable permittivity of the dispersion, are used to load each element individually. This design incorporates thin fluidic channels within a PDMS layer below the substrate leading to individual unit cells that provide a closed pressure-driven subsystem that contains the dispersion. With the capability to individually control each cell, groups of cells can be locally altered (individually or in groups) to create gratings and other electromagnetically agile features across the surface or within the volume of a radome or other covering. Simulations and measurements of an S-band tunable design using colloidal Barium Strontium Titanate dispersed Silicone oil are provided to demonstrate the capability to adjust the stop-band characteristics of the FSS across the S-band.