in this study, silver nanoparticles were synthesized  using the fungus, aspergillus fumigatus. the effects of three independent variables including glucose content of culture media, initial ph and initial spore concentration on biosynthesis of silver nanoparticles were investigated. these variables affect cell morphology, cell mass, size and morphology of silver nanoparticles and degree of silv...

objectives:biofilms are communities of bacteria attached to surfaces through an external polymeric substances matrix. in the meantime, acinetobacterbaumannii is the predominant species related to nosocomial infections. in the present study, the effect of silver nanoparticles alone and in combination with biocides and imipenem against planktonic and biofilms of a. baumannii was assessed.  materi...

the aim of this study is experimental assay of sensitivity and stability of a bimetallic silver/gold spr sensor chip. this chip utilizes the sensitivity of the silver and the stability of the gold. moreover, the silver layer (instead of usual cr or ti layer) was used as an adhesive intermediate layer between the gold layer and the glass substrate. the optimization of the gold/silver thickness u...

Maintaining optimal visual performance is a difficult task in the photodynamic coastal and estuarine waters in which western North Atlantic sciaenid fishes support substantial commercial and recreational fisheries. Unavoidable tradeoffs exist between visual sensitivity and resolution, yet sciaenid visual systems have not been characterized despite strong species-specific ecomorphological and mi...

Sciaenid fishes are important models of fish sound production, but investigations into their auditory abilities are limited to acoustic pressure measurements on five species. In this study, we used auditory brainstem response (ABR) to assess the pressure and particle acceleration thresholds of six sciaenid fishes commonly found in Chesapeake Bay, eastern USA: weakfish (Cynoscion regalis), spott...

silver has been known and used as a potent antimicrobial and wound healing agent since ancient time. silver compounds have had other ancient applications through which greeks, romans and egyptians had used silver compounds as food and water preservative. silver and silver-based antimicrobials were put away after the discovery of antibiotics. meanwhile, with almost a century application of antib...

The evolution of biosonar (production of high-frequency sound and reception of its echo) was a key innovation of toothed whales and dolphins (Odontoceti) that facilitated phylogenetic diversification and rise to ecological predominance. Yet exactly when high-frequency hearing first evolved in odontocete history remains a fundamental question in cetacean biology. Here, we show that archaic odont...

The total number of corpora lutea developed in the left and right overies of 170 white-toothed shrews (Crocidura russula monacha) differed significantly, showing a functional dominance of the left ovary. Blastocytes were equally distributed in both uterine horns.

As the Chinese national fish, large yellow croaker (Pseudosciaena crocea) can generate intermittent sounds. In this study, the acoustic characteristics of the sound signals recorded from three groups of net-cage-cultured large yellow croaker at different ages (7-8-month old, 13-15-month old, and 3-years old) were investigated. The exponential oscillation function derived from the speech signal ...