The Use of PGPB to Promote Plant Hydroponic Growth.

Improvements to the world's food supply chain are needed to ensure sufficient food is produced to meet increasing population demands. Growing food in soilless hydroponic systems constitutes a promising strategy, as this method utilizes significantly less water than conventional agriculture, can be situated in urban areas, and can be stacked vertically to increase yields per acre. However, further research is needed to optimize crop yields in these systems. One method to increase hydroponic plant yields involves adding plant growth-promoting bacteria (PGPB) into these systems. PGPB are organisms that can significantly increase crop yields via a wide range of mechanisms, including stress reduction, increases in nutrient uptake, plant hormone modulation, and biocontrol. The aim of this review is to provide critical information for researchers on the current state of the use of PGPB in hydroponics so that meaningful advances can be made. An overview of the history and types of hydroponic systems is provided, followed by an overview of known PGPB mechanisms. Finally, examples of PGPB research that has been conducted in hydroponic systems are described. Amalgamating the current state of knowledge should ensure that future experiments can be designed to effectively transition results from the lab to the farm/producer, and the consumer.

A comparison of 3 ventilation strategies in children younger than 1 year using a Proseal laryngeal mask airway: a randomized controlled trial.

STUDY OBJECTIVE: To determine quantitative differences in several routinely measured ventilation parameters using a standardized anesthetic technique and 3 different ventilation modalities in patients younger than 1 year with a ProSeal laryngeal mask airway (PLMA). DESIGN: Randomized prospective study. SETTING: Tertiary care pediatric hospital. PATIENTS: Thirty-nine American Society Anesthesiologists classifications 1 to 2, pediatric patients younger than 1 year. INTERVENTIONS: Three different ventilation strategies (spontaneous ventilation [SV], pressure support ventilation [PSV], and pressure-controlled ventilation [PCV]) were randomly applied to patients who underwent a standardized mask induction with sevoflurane/oxygen and propofol 2 mg/kg and fentanyl 2 µg/kg administered intravenously followed by PLMA insertion. Patients were maintained on sevoflurane and N2O. MEASUREMENTS: We measured the differences in end-tidal CO2 (etco2), tidal volume (TV), and respiratory rate (RR) over time between SV, PSV, and PCV. These data were recorded at 5-minute intervals. MAIN RESULTS: etco2 (mm Hg) was not significantly higher in the SV vs PSV (P=2.11) and SV vs PCV (P=.24). TV (mL/kg) was significantly lower in SV vs PSV (P<.005) and SV vs PCV (P<.005). RR was not significantly higher in SV vs PSV (P=.43), but was significantly higher in SV vs PCV (P<.005). Three patients in the SV group and 1 patient in the PSV group failed to initiate SV and required PCV and were thus excluded from analysis. CONCLUSIONS: All 3 modes of ventilation using a PLMA were safe in children younger than 1 year. Although we did not observe a statistically significant increase in etco2, differences in TV and RR, and the small but significant incidence of apnea may make PSV or PCV more optimal ventilation strategies in children younger than 1 year when using a PLMA.

Comparing 3 ventilation modalities by measuring several respiratory parameters using the ProSeal laryngeal mask airway in children.

STUDY OBJECTIVE: To determine quantitative differences in several routinely measured ventilation parameters using a standardized anesthetic technique and 3 different ventilation modalities in pediatric patients with a ProSeal laryngeal mask airway (PLMA). DESIGN: Randomized prospective study. SETTING: Pediatric hospital of a tertiary care academic medical center. PATIENTS: Thirty-three, American Society of Anesthesiologists classification 1-2, pediatric patients (12 months to 5 years). INTERVENTIONS: Three different ventilation strategies: spontaneous ventilation (SV), pressure support ventilation (PSV), and pressure-controlled ventilation (PCV) were randomly applied to patients who underwent a standardized mask induction with sevoflurane/oxygen and propofol 3 mg/kg and morphine 0.05 mg/kg administered intravenously followed by PLMA insertion. Patients were maintained on sevoflurane and N2O. MEASUREMENTS: We measured the differences in end-tidal CO2 (Etco2), tidal volume, and respiratory rate over time between SV, PSV, and PCV. These data were recorded at 5-minute intervals. MAIN RESULTS: Etco2 (mm Hg) was significantly higher in the SV vs PSV (P=.016) and vs PCV (P<.001). Tidal volume (mL/kg) was significantly lower in SV vs PSV (P<.001) and vs PCV (P<.001). Respiratory rate (breaths/min) was significantly higher in SV vs PSV (P<.001) and vs PCV (P=.005). CONCLUSIONS: All 3 modes of ventilation using a PLMA were safely used. Our SV group was noted to have a significantly higher Etco2 when compared with PSV and PCV with a mean Etco2 over time in excess of 55 mm Hg. PSV and PCV were found to be more appropriate ventilation strategies to more optimally control Etco2 over time in these patients.