One of the greatest challenges we face today is the sustainable production, storage, and distribution of electrical power. One emerging technology with great promise in this area is that of metal-air fuel cells—a long-term and reusable electricity storage system made from a reactive metal anode and a saline solution. In this study the authors tested several different types of metal to determine which was the most suitable for this application. They found that a fuel cell with a magnesium anode was superior to fuel cells made from aluminum or zinc, producing a voltage and current sufficient for real-world applications such as charging a mobile phone.

In South Asian countries, the major cause of oral cancer is reported to be chewing paan, which is comprised of betel leaf daubed with slaked lime paste and areca nut. To investigate how paan may contribute to the onset of cancer, the authors treated two immortalized cell lines with extracts of betel leaf, areca nut, and lime and evaluated how these treatments affected cell proliferation and cell death. Initial results indicate that while betel leaf alone may inhibit cell growth, areca nut promoted cancer cell survival and proliferation, even when co-treated with betel leaf. These data suggest that areca nut could exacerbate the progression of oral cancer in humans.

Climate records indicate that there has been a trend of decreasing annual snowfall totals throughout the United States during the peak winter season. However, New Jersey has seen a significant increase in snowfall over the past 126 years of recorded observations. The authors hypothesize that although annual snowfall has remained the same on average, the frequencies of major and minor snowfall events have noticeably increased. They found that there was no significant evidence for an increase in the frequency of minor events (1.1-inch to 4.0-inch events), but there was evidence for an increase in the frequency of major events (4.1+ inch events). The results imply that a warming climate might be opening up opportunities for more snowfall.

Gun violence has been a serious issue in the South Side of Chicago for a long time. To intervene, regulators have passed legislation they hoped to curb -if not completely eradicate- the issue. However, there is little analysis done on how effective the various laws have been at reducing gun violence. Here the authors explore the association between firearm purchase laws passed between 1993-2018 and the incidence of gun homicide in Chicago's South Side. Their analysis suggests that some laws have been more effective than others, while some might have exacerbated the issue. However, they do not consider other contributing factors, which makes it difficult to prove causation without further investigation.

Recurrent neural networks (RNNs) are useful for text generation since they can generate outputs in the context of previous ones. Baroque music and language are similar, as every word or note exists in context with others, and they both follow strict rules. The authors hypothesized that if we represent music in a text format, an RNN designed to generate language could train on it and create music structurally similar to Bach’s. They found that the music generated by our RNN shared a similar structure with Bach’s music in the input dataset, while Bachbot’s outputs are significantly different from this experiment’s outputs and thus are less similar to Bach’s repertoire compared to our algorithm.

Reducing paint drying time is an important step in improving production efficiency and reducing costs. The authors hypothesized that decreased humidity would lead to faster drying, ultraviolet (UV) light exposure would not affect the paint colors differently, white light exposure would allow for longer wavelength colors to dry at a faster rate than shorter wavelength colors, and substrates with higher roughness would dry slower. Experiments showed that trials under high humidity dried slightly faster than trials under low humidity, contrary to the hypothesis. Overall, the paint drying process is very much dependent on its surrounding environment, and optimizing the drying process requires a thorough understanding of the environmental factors and their interactive effects with the paint constituents.

This study examines the higher harmonics in an oscillating string by analyzing the sound produced by a guitar with a spectrum analyzer. The authors mathematically hypothesized that the higher harmonics in the series of the directly excited 2^nd harmonic contain the alternate frequencies of the fundamental series, the higher harmonics of the directly excited 3^rd harmonic series contain every third frequency of fundamental series, and so on. To test the hypotheses, they enforced artificial nodes to excite the 2^nd, 3^rd, and 4^th harmonics directly, and analyzed the resulting spectrum to verify the mathematical hypothesis. The data analysis corroborates both hypotheses.

In this study the author undertakes a careful characterization of a special type of chemical reaction, called an oscillating Belousov-Zhabotinsky (or B-Z) reaction, which has a number of existing applications in biomedical engineering as well as the potential to be useful in future developments in other fields of science and engineering. Specifically, she uses experimental measurements in combination with computational analysis to investigate whether the reaction is cohesive – that is, whether the oscillations between chemical states will remain consistent or change over time as the reaction progresses. Her results indicate that the reaction is not cohesive, providing an important foundation for the development of future technologies using B-Z reactions.

In this study, the authors investigate the effects of sodium levels on blood pressure, one of the most common medical problems worldwide. They used a simulated blood vessel constructed from dialysis tubing to carefully analyze pressure changes resulting from various levels of sodium in the external solution. They found that when the sodium concentration in the simulated blood vessel was higher than the external fluid, internal pressure increased, while the reverse was true when the sodium concentration was lower than in the surrounding environment. These results highlight the potential for sodium concentration to have a significant effect on blood pressure in humans by affecting the rate of osmosis across the boundaries of actual blood vessels.

As the world struggled to grapple with the emerging COVID-19 pandemic in 2020, many countries instated policies to help minimize the spread of the virus among residents. This inadvertently led to a decrease in travel, and in some cases, industrial output, two major sources of pollutants in today's world. Here, the authors investigate whether California's shelter-in-place policy was associated with a measurable decrease in water and air pollution in that state between June and July of 2020, compared to the preceeding five years. Their findings suggest that, by some metrics, air quality improved within certain areas while water quality was relatively unchanged. Overall, these findings suggest that changing human behavior can, indeed, help reduce the level of air pollutants that compromise air quality.