One-pot three-component domino protocol for the synthesis of novel pyrano[2,3-d]pyrimidines as antimicrobial and anti-biofilm agents.

A simple and facile synthesis of a series of novel pyrano[2,3-d]pyrimidines has been achieved successfully via the one-pot three-component reaction of 2-amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[4,3-b]pyran-3-carbonitriles, DMF-DMA and arylamines in the presence of 1-butyl-3-methylhydrogensulphate [Bmim]HSO4 ionic liquid. This method has several advantages such as high yields, clean reaction, simple methodology and short reaction times. The synthesized compounds were evaluated for their antimicrobial activity against Gram-positive, Gram-negative and different Candida strains.

Directed Kinetic Self-Assembly of Mounds on Patterned GaAs (001): Tunable Arrangement, Pattern Amplification and Self-Limiting Growth.

We present results demonstrating directed self-assembly of nanometer-scale mounds during molecular beam epitaxial growth on patterned GaAs (001) surfaces. The mound arrangement is tunable via the growth temperature, with an inverse spacing or spatial frequency which can exceed that of the features of the template. We find that the range of film thickness over which particular mound arrangements persist is finite, due to an evolution of the shape of the mounds which causes their growth to self-limit.

Design, Synthesis, and In Vitro Antimicrobial Evaluation of Fused Pyrano[3,2-e]tetrazolo[1,5-c]pyrimidines and Diazepines.

A series of novel pyranochromene-containing tetrazoles fused with pyrimidinethiones, pyrimidines, and diazepines 3a-f, 4a-f, and 5a-f were synthesized by condensation of the corresponding tetrazoles 2a-f with carbon disulfide, benzaldehyde, and 4-methoxy phenacyl bromide, respectively. The compound 2a-f was obtained by reaction of pyrano[3,2-c]chromenes 1a-f with sodium azide. The structures of the newly synthesized compounds 2a-f to 5a-f were established on the basis of their elemental analyses, IR, (1)H NMR, (13)C NMR, and mass spectral data.

Enhanced electro-optic phase shifts in suspended waveguides.

We demonstrate enhanced electro-optic phase shifts in suspended InGaAs/InGaAsP quantum well waveguides compared to attached waveguides. The enhancement stems from an improved overlap between the optical mode and the multiple quantum well layers in thin waveguides when the semiconductor material beneath the waveguide is selectively etched. The measured voltage length product is 0.

Demonstration of balanced coherent detection using polymer optical waveguide integrated distributed traveling-wave photodetectors.

We have demonstrated balanced coherent detection using distributed balanced traveling-wave photodetectors integrated with single mode polymer optical waveguides. Balanced distributed traveling-wave photodetectors having 3 dB bandwidth of 20 GHz exhibited 20 dB signal to noise ratio improvement measured at 15 GHz modulation frequency in a balanced coherent detection demonstration.