Dopant engineering for ZnO electron transport layer towards efficient perovskite solar cells.

The conventional electron transport layer (ETL) TiO2 has been widely used in perovskite solar cells (PSCs), which have produced exceptional power conversion efficiencies (PCE), allowing the technology to be highly regarded and propitious. Nevertheless, the recent high demand for energy harvesters in wearable electronics, aerospace, and building integration has led to the need for flexible solar cells. However, the conventional TiO2 ETL layer is less preferred, where a crystallization process at a temperature as high as 450 °C is required, which degrades the plastic substrate. Zinc oxide nanorods (ZnO NRs) as a simple and low-cost fabrication material may fulfil the need as an ETL, but they still suffer from low PCE due to atomic defect vacancy. To delve into the issue, several dopants have been reviewed as an additive to passivate or substitute the Zn2+ vacancies, thus enhancing the charge transport mechanism. This work thereby unravels and provides a clear insight into dopant engineering in ZnO NRs ETL for PSC.

Combining molecular docking and molecular dynamics studies for modelling Staphylococcus aureus MurD inhibitory activity.

The ATP-dependent bacterial MurD enzyme catalyses the formation of the peptide bond between cytoplasmic intermediate UDP-N-acetylmuramoyl-L-alanine and D-glutamic acid. This is essential for bacterial cell wall peptidoglycan synthesis in both Gram-positive and Gram-negative bacteria. MurD is recognized as an important target for the development of new antibacterial agents. In the present study we prepared the 3D-stucture of the catalytic pocket of the Staphylococcus aureus MurD enzyme by homology modelling. Extra-precision docking, binding free energy calculation by the MM-GBSA approach and a 40 ns molecular dynamics (MD) simulation of 2-thioxothiazolidin-4-one based inhibitor $1 was carried out to elucidate its inhibition potential for the S. aureus MurD enzyme. Molecular docking results showed that Lys19, Gly147, Tyr148, Lys328, Thr330 and Phe431 residues are responsible for the inhibitor-protein complex stabilization. Binding free energy calculation revealed electrostatic solvation and van der Waals energy components as major contributors for the inhibitor binding. The inhibitor-modelled S. aureus protein complex had a stable conformation in response to the atomic flexibility and interaction, when subjected to MD simulation at 40 ns in aqueous solution. We designed some molecules as potent inhibitors of S. aureus MurD, and to validate the stability of the designed molecule D1-modelled protein complex we performed a 20 ns MD simulation. Results obtained from this study can be utilized for the design of potent S. aureus MurD inhibitors.

Pharmacophore generation, atom-based 3D-QSAR and molecular dynamics simulation analyses of pyridine-3-carboxamide-6-yl-urea analogues as potential gyrase B inhibitors.

DNA gyrase subunit B (GyrB) is an attractive drug target for the development of antibacterial agents with therapeutic potential. In the present study, computational studies based on pharmacophore modelling, atom-based QSAR, molecular docking, free binding energy calculation and dynamics simulation were performed on a series of pyridine-3-carboxamide-6-yl-urea derivatives. A pharmacophore model using 49 molecules revealed structural and chemical features necessary for these molecules to inhibit GyrB. The best fitted model AADDR.13 was generated with a coefficient of determination (r²) of 0.918. This model was validated using test set molecules and had a good r² of 0.78. 3D contour maps generated by the 3D atom-based QSAR revealed the key structural features responsible for the GyrB inhibitory activity. Extra precision molecular docking showed hydrogen bond interactions with key amino acid residues of ATP-binding pocket, important for inhibitor binding. Further, binding free energy was calculated by the MM-GBSA rescoring approach to validate the binding affinity. A 10 ns MD simulation of inhibitor #47 showed the stability of the predicted binding conformations. We identified 10 virtual hits by in silico high-throughput screening. A few new molecules were also designed as potent GyrB inhibitors. The information obtained from these methodologies may be helpful to design novel inhibitors of GyrB.

Synthesis and Biological Screening of 5-{[(4,6-Disubstituted pyrimidine-2-yl)thio]methyl}-N-phenyl-1,3,4-thiadiazol-2-amines.

A number of substituted-α,ß-unsaturated carbonyl compounds (1a-i) were prepared by Claisen-Schmidt condensation of substituted acetophenone with selected araldehydes, which on cycloaddition with thiourea furnished 4,6-disubstituted pyrimidine-2-thiols (2a-i). Reaction of (2a-i) with ethyl chloroacetate followed by condensation with hydrazine hydrate yielded 2-[(4,6-disubstituted pyrimidine-2-yl) thio] acetohydrazides (4a-c). Condensation of compounds (4a-c) with phenyl isothiocyanate gave 2-{[(4,6-disubstituted pyrimidine-2-yl) thio] acetyl}-N-phenylhydrazinecarbothioamides (5a-c) which on treatment with concentrated sulphuric acid afforded titled compounds 5-{(4,6-disubstituted pyrimidine-2-yl) thio] methyl}-N-phenyl-1,3,4-thiadiazole-2-amines (6a-c). These compounds have been characterized on the basis of elemental analysis, IR, (1)H NMR and MS. Compounds have been evaluated for their anticancer and antioxidant activities. Compounds 2b, 2c and 6b exhibited significant antitumor activity against human breast cancer MCF 7 cell line. However, moderate antioxidant activity was observed with compounds 2c, 2d, 2g and 6b.

Pisotriquetral arthritis: a case report.

We describe a case of pisotriquetral arthritis associated with ulnar nerve paraesthesiae. We briefly review the literature and discuss the aetiology of this particular case.

An in vitro study on the antimicrobial effect of select heterocyclic nitrogen compounds.

In vitro antimicrobial activity of seventeen heterocyclic nitrogen compounds {2-substituted pyrido [1,2-a] pyrimidin -4-oxo-1 [4]-3-Carbonitriles and ethyl 5-amino-3-(substituted) - pyrazole-3-Carboxylates} was tested against Escherichia coli, Bacillus subtilis and candida albicans strains, Antimicrobial activity was measured using standard two -fold serial dilution method and the minimum inhibitory concentration (MIC) values are determined, The MIC of pyrazoles and pyrido[1,2 -a] pyrimidines are found to be 25 µg/ml to 50 µg/ml against E. Coli and 50 µg/ml against B.subtilis respectively. Both pyrazole and pyrido [1,2-a] Pyrimidines are found to be totally ineffective against C. albicans.