Design,Synthesis, and Biological Evaluation of 3,5‐Disubstituted 2‐Pyrazineamide Derivatives as Antitubercular Agents

A novel series of 3,5‐disubstituted‐2‐pyrazineamide derivatives ( 5a–5o ) were synthesized and studied for their potential as antitubercular agents. Among them, the compounds 5a , 5g , and 5m showed the good minimal inhibitory concentration of 20, 25, and 25 μg/mL, respectively. The compound 5a displayed excellent minimum inhibitory concentration of 10 μg/mL and is four times more potent compared with the standard drug, rifampicin concentration. In silico docking studies revealed that the compounds 5a and 5c can bind strongly in the active site of 2FUM enzyme and prevent enzyme–substrate interactions. In addition, in silico docking studies were calculated, and based on the data obtained, compound 5a displayed excellent drug‐like properties.     

Facile combustion synthesis of Ag2O nanoparticles using cantaloupe seeds and their multidisciplinary applications

Silver oxide nanoparticles (Ag₂O NPs) were prepared using cantaloupe (Cucumis melo) seeds as a fuel by employing a green synthesis method. The prepared Ag₂O NPs were investigated using powder X-ray diffraction (PXRD), UV–visible spectrum, Fourier transform infrared analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive spectroscopy, and photoluminescence studies. PXRD data reveal the establishment of cubic crystal structure of Ag₂O NPs. According to SEM and TEM results, the morphology of the prepared NPs was agglomerated and spherical. The photodegradation activity of the prepared Ag₂O NPs over methylene blue dye was promising under visible light irradiation. Furthermore, the antimicrobial assay of the synthesized Ag₂O NPs was carried out by the disc diffusion method against Gram-positive and Gram-negative microbial strains.     

Paramagnetic nematic liquid crystals

The paper reports new nematic liquid crystals that are paramagnetic.     

The first total synthesis of the 6-hydroxy-4E-sphingenines

Ceramides containing the 6-hydroxy-4E-sphingenines, previously unknown long-chain bases, have recently been found in human skin. A total synthesis of 6-hydroxy-4E-sphingenines has been achieved.     

Spectroscopy and imaging of metal-organic interfaces using BEEM

Charge injection from metal electrodes to organics is a subject of intense scientific investigation for organic electronics. Ballistic electron emission microscopy (BEEM) enables spectroscopy and imaging of buried interfaces with nanometer resolution. Spatial non-uniformity of carrier injection is observed for both Ag-PPP (poly-paraphenylene) and Ag-MEHPPV (poly-2-methoxy-5-2-ethyl-hexyloxy-1,4-phenylenevinylene) interfaces. BEEM current images are found to correlate only marginally with the surface topography of the Ag film.     

Measurement of optical constants of thin polymer films using spectrally resolved white light interferometry

Using the spectrally resolved white light interferometry we present our experimental results on the measurement of the optical constants of thin polymer films coated on a transparent substrate. As an extension to our previous work (J. Opt. Soc. Am. B12, 1559 (1995)) on thick glass plates, we have shown here that this technique can be effectively applied to very thin polymer films also. We have improved the accuracy of our results by using the Sellmeier dispersion formula for fitting the data. From the width and position of the zero-order fringe and the frequency of modulations in the white light spectrum, the refractive indexn(λ) and thicknesst of the thin polymer films are calculated. To study the accuracies involved in the technique, PVA, PMMA and PS films of varied thicknesses are coated on glass plates and the measured values are compared with ellipsometer studies.