Whole genome analysis of Rhizopus species causing rhino-cerebral mucormycosis during the COVID-19 pandemic

IntroductionMucormycosis is an acute invasive fungal disease (IFD) seen mainly in immunocompromised hosts and in patients with uncontrolled diabetes. The incidence of mucormycosis increased exponentially in India during the SARS-CoV-2 (henceforth COVID-19) pandemic. Since there was a lack of data on molecular epidemiology of Mucorales causing IFD during and after the COVID-19 pandemic, whole genome analysis of the Rhizopus spp. isolated during this period was studied along with the detection of mutations that are associated with antifungal drug resistance.Materials and methodsA total of 50 isolates of Rhizopus spp. were included in this prospective study, which included 28 from patients with active COVID-19 disease, 9 from patients during the recovery phase, and 13 isolates from COVID-19-negative patients. Whole genome sequencing (WGS) was performed for the isolates, and the de novo assembly was done with the Spades assembler. Species identification was done by extracting the ITS gene sequence from each isolate followed by searching Nucleotide BLAST. The phylogenetic trees were made with extracted ITS gene sequences and 12 eukaryotic core marker gene sequences, respectively, to assess the genetic distance between our isolates. Mutations associated with intrinsic drug resistance to fluconazole and voriconazole were analyzed.ResultsAll 50 patients presented to the hospital with acute fungal rhinosinusitis. These patients had a mean HbA1c of 11.2%, and a serum ferritin of 546.8 ng/mL. Twenty-five patients had received steroids. By WGS analysis, 62% of the Rhizopus species were identified as R. delemar. Bayesian analysis of population structure (BAPS) clustering categorized these isolates into five different groups, of which 28 belong to group 3, 9 to group 5, and 8 to group 1. Mutational analysis revealed that in the CYP51A gene, 50% of our isolates had frameshift mutations along with 7 synonymous mutations and 46% had only synonymous mutations, whereas in the CYP51B gene, 68% had only synonymous mutations and 26% did not have any mutations.ConclusionWGS analysis of Mucorales identified during and after the COVID-19 pandemic gives insight into the molecular epidemiology of these isolates in our community and establishes newer mechanisms for intrinsic azole resistance

Base-Promoted Selective Synthesis of 2<i>H</i>‑Pyranones and Tetrahydronaphthalenes via Domino Reactions

A highly efficient domino protocol has been developed for the synthesis of 6-aryl-4-(methylthio/amine-1-yl)-2-oxo-2<i>H</i>-pyran-3-carbonitriles and 4-aryl-2-(amine-1-yl)-5,6,7,8-tetrahydronaphthalene-1-carbonitriles from simple and readily available α-aroylketene dithioacetals, malononitrile, secondary amines, and cyclohexanone. This elegant domino process involved consecutive addition–elimination, intramolecular cyclization, and ring opening and closing sequences. Notably, in situ generated 2-imino-4-(methylthio/amine-1-yl)-6-aryl-2<i>H</i>-pyran-3-carbonitrile plays multiple roles in the construction of various novel polyaromatic hydrocarbons

Experimental Investigation on Eliminating Supercooling Nature of Ice and Improving its Energy Storage Performance to Establish an Energy-Efficient Cold Thermal Storage

© 2023 Elsevier Ltd. All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1016/j.tsep.2023.102059Energy efficiency is a crucial parameter for sustainable development. Eliminating the supercooling and enhancing the energy storage performance of the ice-cold thermal storage system (CTSS) is vital to make it more reliable and sustainable. In the present study, the supercooling issue of ice was eliminated using 1-Hexadecanol. Further, the energy storage performance of ice was enhanced using an aluminium honeycomb core (AHC), which is considered to be the most promising method of improving the charging performance. The optimal size of AHC was identified by performing the experiments with three sizes (large, medium and small) of AHC. Further, the discharging [heat transfer fluid temperature (Tw) = 13 °C)] and the charging [Tw = -3, -6 and -9 °C)] experiments were conducted before and after adding the optimal size AHC inside the various diameters (64, 85 and 105 mm) spherical enclosure (S.E)). The supercooling nature of water is eliminated after adding 3 wt% of 1-Hexadecanol, and the medium-size AHC is optimal. The optimum heat transfer fluid temperature for charging is -6 °C, and the smallest diameter S.E provided better discharging and charging performance. The average decrease in charging time and improvement in charging rate realised upon adding AHC are 30.23% and 43.54%, respectively. When the AHC is added with ice, the effective utilisation ratio improved considerably (6.13 to 6.48), and the energy storage capacity reduced slightly (1.76% to 1.91%). The above experimental results implicate that the employment of AHC would pave the way for effectively enhancing the energy storage performance of ice.Peer reviewe

Tetraphenylethene–2-Pyrone Conjugate: Aggregation-Induced Emission Study and Explosives Sensor

Design and synthesis of a novel tetraphenylethene–2-pyrone <b>(TPEP)</b> conjugate exhibiting donor–acceptor characteristics is reported. The localized frontier molecular orbitals (DFT studies) and the solvent polarity dependent photoluminescence characteristics directly corroborate the presence of intramolecular charge transfer character in <b>TPEP</b>. <b>TPEP</b> is poorly emissive in the solution state. In contrast, upon aggregation (THF/water mixtures), <b>TPEP</b> exhibits aggregation-induced emission enhancement. Upon aggregation, dyad <b>TPEP</b> forms a fluorescent nanoaggregate which was confirmed by transmission electron microscopy imaging studies. The luminescence nanoaggregates were elegantly exploited for selective detection of nitro aromatic compounds (NACs). It was found that nanoaggregates of <b>TPEP</b> were selectively sensing the picric acid over the other NACs. Efficiency of the quenching process was further evaluated by the Stern–Volmer equation. <b>TPEP</b>-based low-cost fluorescent test strips were developed for the selective detection of picric acid

Tetraphenylethene–2-Pyrone Conjugate: Aggregation-Induced Emission Study and Explosives Sensor

Design and synthesis of a novel tetraphenylethene–2-pyrone <b>(TPEP)</b> conjugate exhibiting donor–acceptor characteristics is reported. The localized frontier molecular orbitals (DFT studies) and the solvent polarity dependent photoluminescence characteristics directly corroborate the presence of intramolecular charge transfer character in <b>TPEP</b>. <b>TPEP</b> is poorly emissive in the solution state. In contrast, upon aggregation (THF/water mixtures), <b>TPEP</b> exhibits aggregation-induced emission enhancement. Upon aggregation, dyad <b>TPEP</b> forms a fluorescent nanoaggregate which was confirmed by transmission electron microscopy imaging studies. The luminescence nanoaggregates were elegantly exploited for selective detection of nitro aromatic compounds (NACs). It was found that nanoaggregates of <b>TPEP</b> were selectively sensing the picric acid over the other NACs. Efficiency of the quenching process was further evaluated by the Stern–Volmer equation. <b>TPEP</b>-based low-cost fluorescent test strips were developed for the selective detection of picric acid