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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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Aggression of Carcharhinus leucas and Carcharhinus amblyrhynchos towards humans

Mignone et al. | May 11, 2021

Aggression of <i>Carcharhinus leucas</i> and <i>Carcharhinus amblyrhynchos</i> towards humans

This paper presents findings on Carcharhinus leucas (bull shark) and Carcharhinus amblyrhynchos (grey reef shark) aggression towards humans at Beqa Adventure Divers in Shark Reef Marine Reserve, Fiji. We hypothesized that grey reef sharks would receive more prods than bull sharks because grey reef sharks are typically more aggressive than bull sharks. The results supported our hypothesis, as an individual grey reef shark received 2.44 prods on average per feed, while a bull shark had an average of 0.61. These findings are meaningful not only to the world’s general understanding of shark aggression, but also to human protection against grey reef sharks as well as public education on bull sharks and the conservation of the species.

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The role of CYP46A1 and its metabolic product, 24S-hydroxycholesterol, in Neuro 2A cell death

Ni et al. | May 11, 2021

The role of CYP46A1 and its metabolic product, 24S-hydroxycholesterol, in Neuro 2A cell death

Cholesterol is a major component of neuronal cell membrane and myelin sheath. In this study, the authors either transfected Neuro 2A cells with CYP46A1 cDNA or treated the cells with 24SHC. Cells expressing CYP46A1 had significantly less viability compared to the negative control. Up to 55% reduction in cell viability was also observed in 24S-HC-treated cells. This work supports that CYP46A1 and 24S-HC could directly trigger cell death. The direct involvement of 24S-HC in cell death provides further evidence that 24S-HC can be a promising biomarker for diagnosing brain damage severity.

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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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Comparative screening of dose-dependent and strain-specific antimicrobial efficacy of berberine against a representative library of broad-spectrum antibiotics

Sun et al. | May 10, 2021

Comparative screening of dose-dependent and strain-specific antimicrobial efficacy of berberine against a representative library of broad-spectrum antibiotics

We hypothesize that berberine has broad-spectrum antibacterial properties, along with potency that is comparable to current broad-spectrum antibiotics that are commercially available. Here, we screened berberine against four strains of bacteria and evaluated its antimicrobial activity against five broad-spectrum antibiotics from different classes to better quantify berberine’s antibacterial activity and compare its efficacy as an antibacterial agent to the broad-spectrum antibiotics. Our results indicated that berberine had strain-selective cytotoxic effects and was significantly less potent than most of the broad-spectrum antibiotics

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Synthesis of a novel CCR1 antagonist for treatment of glioblastoma

Jan et al. | May 05, 2021

Synthesis of a novel CCR1 antagonist for treatment of glioblastoma

Glioblastoma is a brain cancer caused by the presence of a fast-growing, malignant tumor in the brain. As of now, this cancer is universally lethal due to lack of efficacious treatment options. C-C chemokine receptor 1 (CCR1) is a G-protein coupled receptor that controls chemotaxis, the movement of cells in response to chemical stimuli. This research aims to synthesize potential CCR1 antagonists by coupling carboxylic acids with a triazole core. We synthesized these compounds using a simple carboxylic acid coupling and confirmed the identity of the final compounds using nuclear magnetic resonance (NMR) spectroscopy.

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Open Source RNN designed for text generation is capable of composing music similar to Baroque composers

Goel et al. | May 05, 2021

Open Source RNN designed for text generation is capable of composing music similar to Baroque composers

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.

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