M Karaman | PubMed Health

PubMed2001

Vancomycin-resistant enterococci in neonates.

Fecal-oral transmission of vancomycin-resistant strains of Enterococci (VRE), which colonize the human gastrointestinal tract, has led to nosocomial epidemics in recent years. The aim of this study was to establish the incidence and associated factors of fecal colonization with VRE in neonates. In our hospital 110 rectal swab specimens collected in the neonatal intensive care unit (NICU) were examined for VRE. For comparison, rectal swabs collected from 42 healthy neonates on the obstetrics ward were also analyzed. Of the NICU patients, 8 had VRE MICs of 8-64 microg/ml for vancomycin and 2-32 microg/ml for teicoplanin, whereas none of the healthy newborns, had VRE (p < 0.05). All patients positive for VRE had factors known to be associated with VRE carriage, such as low birth weight or long-term antibiotic therapy.

Cross Infection↗

PubMed2001

Digital phased array beamforming using single-bit delta-sigma conversion with non-uniform oversampling.

Digital beamforming based on oversampled delta-sigma (delta sigma) analog-to-digital (A/D) conversion can reduce the overall cost, size, and power consumption of phased array front-end processing. The signal resampling involved in dynamic delta sigma beamforming, however, disrupts synchronization between the modulators and demodulator, causing significant degradation in the signal-to-noise ratio. As a solution to this, we have explored a new digital beamforming approach based on non-uniform oversampling delta sigma A/D conversion. Using this approach, the echo signals received by the transducer array are sampled at time instants determined by the beamforming timing and then digitized by single-bit delta sigma A/D conversion prior to the coherent beam summation. The timing information involves a non-uniform sampling scheme employing different clocks at each array channel. The delta sigma coded beamsums obtained by adding the delayed 1-bit coded RF echo signals are then processed through a decimation filter to produce final beamforming outputs. The performance and validity of the proposed beamforming approach are assessed by means of emulations using experimental raw RF data.

Journal Article↗