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Comparative singlet oxygen photosensitizer efficiency of berberine, rose bengal, and methylene blue by time course nuclear magnetic resonance (NMR) monitoring of a photochemical 4+2 cycloaddition endoperoxide formation

Su et al. | May 14, 2021

Comparative singlet oxygen photosensitizer efficiency of berberine, rose bengal, and methylene blue by time course nuclear magnetic resonance (NMR) monitoring of a photochemical 4+2 cycloaddition endoperoxide formation

Berberine, a natural product alkaloid, has been shown to exert biological activity via in situ production of singlet oxygen when photo irradiated. Berberine utilizes singlet oxygen in its putative mechanism of action, wherein it forms an activated complex with DNA and photosensitizes triplet oxygen to singlet oxygen to specifically oxidize guanine residues, thereby halting cell replication and leading to cell death. This has potential application in photodynamic therapy, alongside other such compounds which also act as photosensitizers and produce singlet oxygen in situ. The quantification of singlet oxygen in various photosensitizers, including berberine, is essential for determining their photosensitizer efficiencies. We postulated that the singlet oxygen produced by photoirradiation of berberine would be superior in terms of singlet oxygen production to the aforementioned photosensitizers when irradiated with UV light, but inferior under visible light conditions, due to its strong absorbance of UV wavelengths.

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The effects of different modes of vocalization and food consumption on the level of droplet transmission of bacteria

Wong et al. | May 10, 2021

The effects of different modes of vocalization and food consumption on the level of droplet transmission of bacteria

Microbial agents reposnsible for respiratory infections are often carried in spittle, which means they can be easily transmitted. Here, the authors investigate how likely certain activities are to spread microbes carried in spittle. They also investigate whether eating certain types of food might reduce the spread of spittle-borne bacteria too.

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Down-regulation of CD44 inhibits Wnt/β-catenin mediated cancer cell migration and invasion in gastric cancer

Baek et al. | May 10, 2021

Down-regulation of CD44 inhibits Wnt/β-catenin mediated cancer cell migration and invasion  in gastric cancer

In this study, we aimed to characterize CD44-mediated regulation of the Wnt/β-catenin signaling pathway, which promotes cancer invasion and metastasis. We hypothesized that CD44 down-regulation will inhibit gastric cancer cell migration and invasion by leading to down-regulation of Wnt/β-catenin signaling. We found that CD44 up-regulation was significantly related to poor prognosis in gastric cancer patients. We demonstrated the CD44 down-regulation decreased β-catenin protein expression level. Our results suggest that CD44 down-regulation inhibits cell migration and invasion by down-regulating β-catenin expression level.

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A Data-Centric Analysis of “Stop and Frisk” in New York City

Bhat et al. | Apr 18, 2021

A Data-Centric Analysis of “Stop and Frisk” in New York City

The death of George Floyd has shed light on the disproportionate level of policing affecting non-Whites in the United States of America. To explore whether non-Whites were disproportionately targetted by New York City's "Stop and Frisk" policy, the authors analyze publicly available data on the practice between 2003-2019. Their results suggest African Americans were indeed more likely to be stopped by the police until 2012, after which there was some improvement.

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The Effect of Wind Mitigation Devices on Gabled Roofs

Kaufman et al. | Feb 20, 2021

The Effect of Wind Mitigation Devices on Gabled Roofs

The purpose of this study was to test devices installed on a gabled roof to see which reduced the actual uplift forces best. Three gabled birdhouse roofs were each modified with different mitigation devices: a rounded edge, a barrier shape, or an airfoil. The barrier edge had no significant effect on the time for the roof to blow off. The addition of airfoil devices on roofs, specifically in areas that are prone to hurricanes such as Florida, could keep roofs in place during hurricanes, thus reducing insurance bills, overall damage costs, and the loss of lives.

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