Aims. We investigate the purely thermal formation of hexamethylenetetramine (HMT, C6H12N4) in interstellar ice analogs from nonphotolysed ice and compare our results with those for the formation from photolysed ice. Methods. We use Fourier transform-infrared spectroscopy to follow residue formation from VUV irradiation of H2CO:NH3 ice mixture in different concentration ratios. We also report th...

We review two strategies for growing ZnO nanowires from zinc salts in aqueous and organic solvents. Wire arrays with diameters in the nanoscale regime can be grown in an aqueous solution of zinc nitrate and hexamethylenetetramine. With the addition of poly(ethylenimine), the lengths of the wires have been increased to 25 mum with aspect ratios over 125. Additionally, these arrays were made vert...

A novel method for the synthesis of polymer-stabilized quantum dots (QDs) was reported through a onepot hydrothermal reaction. Using this method, a phenol formaldehyde resin (PFR) polymer was formed in situ to passivate the surface of the CdS QDs with hexamethylenetetramine as the source of both the monomer and the crosslinking agent, HCHO. The PFR-capped QDs possessed a uniform size distributi...

A series of silver nanoparticles surface-coated with di-n-dodecyldithiophosphate, di-n-cetyldithiophosphate, or di-n-octadecyldithiophosphate have been prepared and have good dispersity in alkanes or kerosene. Stable silver nanofluids can be formed in alkanes or kerosene with the surface-coated silver nanoparticles. Thermal stability of the silver nanofluids has been measured at different tempe...

Emergence of resistant microbes to conventional antibiotics and increased emphasis on health-care costs has raised the concern for the development of new effective antimicrobial reagents. Silver nanoparticles being an excellent broad-spectrum antibacterial agent could be considered as a suitable alternative for existing antibiotic. This study demonstrates the extra-cellular synthesis of stable ...

Research has clarified the properties required for polymers that resist bacterial colonisation for use in medical devices. The increase in antibiotic-resistant microorganisms has prompted interest in the use of silver as an antimicrobial agent. Silver-based polymers can protect the inner and outer surfaces of devices against the attachment of microorganisms. Thus, this review focuses on the mec...

Silver-based dressings have been used extensively in wound management in recent years, but data on their antimicrobial activity in the clinical setting are limited. In order to explore their effects on chronic leg ulcer flora, 14 ulcers were cultured after at least 3 weeks treatment with Aquacel Ag(®) or Acticoat(®). Phenotypic and genetic silver resistance were investigated in a total of 56 is...

In this study, effect of sliver-doping on the crystal structure, the nanofibrous morphology and the photocatalytic activity of titanium oxide nanofibers have been investigated. Silver-doped TiO2 nanofibers having different silver contents were prepared by calcination of electrospun nanofiber mats consisting of silver nitrate, titanium isopropoxide and poly(vinyl acetate) at 600 C. The results a...

Acoustic vibrations of single gold nanorods coated with silver were investigated. We used single-particle pump-probe spectroscopy to monitor the silver deposition through the particle vibrations. Two vibration modes, the breathing mode and extensional mode, are observed, and the vibrational frequencies are measured as functions of the amount of silver deposited on single gold nanorods. The brea...

Introduction Focus: Early (800-1500) commodity money systems (coins) Introduction Stylized facts about evolution of commodity money systems: 1 Started with a single silver coin Initially same size across countries Over time, debased in some countries, not debased in others 2 Next added a second silver coin If original silver coin small, then new silver coin larger If original silver coin large,...