Yield and Water Quality Impacts of Field-Scale Integration of Willow into a Continuous Corn Rotation System.

Agricultural landscape design has gained recognition by the international environmental and development community as a strategy to address multiple goals in land, water, and ecosystem service management; however, field research is needed to quantify impacts on specific local environments. The production of bioenergy crops in specific landscape positions within a grain-crop field can serve the dual purpose of producing cellulosic biomass (nutrient recovery) while also providing regulating ecosystem services to improve water quality (nutrient reduction). The effectiveness of such a landscape design was evaluated by the strategic placement of a 0.

Mass recovery methods for trichloroethylene in plant tissue.

Monitoring expenses form a significant fraction of the costs associated with remediation of contaminated soil and groundwater sites. A novel monitoring method that could result in significant cost savings is the use of plants as monitoring devices; previous work indicates that plant tissue samples, especially trunk (core) and branch samples, can be used to delineate soil and groundwater plumes at phytoremediation sites. An important factor in reducing the uncertainty associated with this sampling method is development of a technique to analyze, both consistently and accurately, the chemicals stored in plant tissue samples.

Frequency of mutation to rifampin resistance in Streptococcus pneumoniae clinical strains: hexA and hexB polymorphisms do not account for hypermutation.

The frequency of mutation to rifampin resistance of 200 clinical Streptococcus pneumoniae isolates was examined. Two peaks were observed in the distribution, with mode frequencies of 2.5 x 10(-7) (20% of isolates) and 2.

In vitro selective concentrations of cefepime and ceftazidime for AmpC beta-lactamase hyperproducer Enterobacter cloacae variants.

This study aimed to compare the selective concentrations of cefepime and ceftazidime on Enterobacter cloacae. A mixed culture of a wild-type ceftazidime/cefepime-susceptible (4x107 CFU/mL) strain and an ampC derepressed Enterobacter cloacae (105 CFU/mL) strain (relative proportions 99.75% and 0.

In vitro selective concentrations of cefepime and ceftazidime for AmpC beta-lactamase hyperproducer Enterobacter cloacae variants.

METHODS: A mixed culture of a wild-type ceftazidime/cefepime-susceptible (4x107 CFU/mL) strain and an ampC derepressed Enterobacter cloacae (105 CFU/mL) strain (relative proportions 99.75% and 0.25%) was challenged for 4 h with different antibiotic concentrations of ceftazidime and cefepime (0.

Very low cefotaxime concentrations select for hypermutable Streptococcus pneumoniae populations.

A mixed culture of an hypermutable hexA Streptococcus pneumoniae mutant strain and its hexA(+) isogenic ancestor was challenged with low cefotaxime concentrations. Despite identical original cefotaxime MICs, the hexA mutant population was significantly selected at very low concentrations, and all of the tested selected variants harbored the Thr550-->Ala mutation in pbp2x. Since cefotaxime selects hypermutators, the risk of secondary acquisition of antibiotic resistance is increased; as expected, the cefotaxime-resistant mutants had a mutation frequency 10 times higher in response to to ciprofloxacin.