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Seven new polyketides including a phenol (1), two diphenyl ethers (2 and 3), two depsidones (4 and 5), and two phthalides (6 and 7) were isolated from the fungus Aspergillus unguis PSU-MF16 along with 27 known compounds. Their structures were determined by extensive spectroscopic analysis. The absolute configurations of 1 and 4−7 were established using comparative analyses of calculated and experimental ECD spectra. Among the new metabolites, 2 exhibited the best antimicrobial activity against Staphylococcus aureus, methicillin-resistant S. aureus, and Microsporum gypseum with equal MIC values of 16 μg/mL. In addition, known emeguisin A displayed potent antimicrobial activity against S. aureus, methicillin-resistant S. aureus, and Cryptococcus neoformans with equal MIC values of 0.5 μg/mL, compared with the standard drugs, vancomycin and amphotericin B. The structure−activity relationship study of the isolated compounds for antimicrobial activity is discussed.

This work presents a simple hydrothermal synthesis of nitrogen-doped carbon dots (N-CDs), fabrication of microfluidic paper-based analytical device (μPAD), and their joint application for colorimetric determination of total cholesterol (TC) in human blood. The N-CDs were characterized by various techniques including transmission electron microscopy (TEM), Xray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD), and the optical and electronic properties of computational models were studied using the time-dependent density functional theory (TD-DFT). The characterization results confirmed the successful doping of nitrogen on the surface of carbon dots. The N-CDs exhibited high affinity toward 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt (ABTS) with the Michaelis−Menten constant (K M ) of 0.018 mM in a test for their peroxidase-like activity. Particularly, since hydrogen peroxide (H 2 O 2 ) is the oxidative product of cholesterol in the presence of cholesterol oxidase, a sensitive and selective method of cholesterol detection was developed. Overall, the obtained results from TD-DFT confirm the strong adsorption of H 2 O 2 on the graphitic N positions of the N-CDs. The laminated three-dimensional (3D)-μPAD featuring a 6 mm circular detection zone was fabricated using a simple wax screen printing technique. Classification of TC according to the clinically relevant criteria (healthy, <5.2 mM; borderline, 5.2−6.2 mM; and high risk, >6.2 mM) could be determined by the naked eye within 10 min by simple comparison using a color chart. Overall, the proposed colorimetric device serves as a low-cost, rapid, simple, sensitive, and selective alternative for TC detection in whole blood samples that is friendly to unskilled end users.

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A coordination complex, lithium hepta­(i-butyl)­silsesquioxane trisilanolate (1; Li-T7), a stable intermediate in silsesquioxane (SQ) syntheses, was successfully isolated in 65% yield and found to be highly soluble in nonpolar solvents such as hexane. The structure of Li-T7 was confirmed by NMR, IR spectroscopy, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, electrospray ionization mass spectrometry, and computational simulation, providing detailed elucidation of the intermolecular self-association of the SQ cage with a box-shaped Li6O6 polyhedron through strong coordination bonds. After acid treatment, Li-T7 undergoes lithium–proton cationic exchange, yielding hepta­(i-butyl)­silsesquioxane trisilanol (2; H-T7) quantitatively. The high yield of H-T7 seems to be influenced by Li–O bonding in the Li-T7 complex that affects the selective formation of hepta­(i-butyl)­silsesquioxane trisilanolate and the bulky i-butyl groups which may prevent decomposition or SQ cage-rearrangement even at reflux under alkaline conditions. Single-crystal X-ray crystallography confirms the presence of the dumbbell-shaped SQ partial cages through strong intermolecular hydrogen bonds. Interestingly, lowering the polarity of the reaction solution by adding dichloromethane results in formation of the cubic octa­(i-butyl)­silsesquioxane (3; T8) cage in a good yield (47%), which is isolated by crystallization from the reaction solution.

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