Impacts of co-contaminants and dilution on perchlorate biodegradation using various carbon sources.

This research investigates the biodegradation of perchlorate in the presence of the co-contaminants nitrate and chlorate using soluble and slow-release carbon sources. In addition, the impact of bio-augmentation and dilution, which results in lower total dissolved salts (TDS) and contaminant levels, is examined. Laboratory microcosms were conducted using actual groundwater and soils from a contaminated aquifer. The results revealed that both soluble and slow-release carbon sources support biodegradation of contaminants in the sequence nitrate > chlorate > perchlorate. Degradation rates, including and excluding lag times, revealed that the overall impact of the presence of co-contaminants depends on degradation kinetics and the relative concentrations of the contaminants. When the lag time caused by the presence of the co-contaminants is considered, the degradation rates for chlorate and perchlorate were two to three times slower. The results also show that dilution causes lower initial contaminant concentrations, and consequently, slower degradation rates, which is not desirable. On the other hand, the dilution resulting from the injection of amendments to support remediation promotes desirably lower salinity levels. However, the salinity associated with the presence of sulfate does not inhibit biodegradation. The naturally occurring bacteria were able to support the degradation of all contaminants. Bio-augmentation was effective only in diluted microcosms. Proteobacteria and Firmicutes were the dominant phyla identified in the microcosms.

The Impact of a Less Restrictive Poststernotomy Activity Protocol Compared With Standard Sternal Precautions in Patients Following Cardiac Surgery.

OBJECTIVE: Guidelines following median sternotomy typically include strict sternal precautions (SP). Recently, alternative approaches propose less functional restrictions while avoiding excessive stress to the sternum. The study aimed to determine the effect of a less restrictive (LR) approach versus a standard SP protocol after median sternotomy. METHODS: The study was a cross-sectional design (n = 364; SP: n = 172, 66.3 [SD = 11.2] years; LR: n = 196, 65.2 [SD = 11.2] years). This study ran in 2 consecutive phases and compared 2 groups after median sternotomy at a community-based hospital. The LR group received instructions on the Keep Your Move in the Tube approach. At 2 to 3 weeks after discharge, sternal instability was assessed using the Sternal Instability Scale, and patients completed a self-reported survey (perceived pain rating/frequency, sternal instability, and functional mobility). The 2 groups were compared using the Mann-Whitney U test and chi-square test (P < .05). RESULTS: There were no significant differences between the 2 groups for all the outcomes, Sternal Instability Scale, pain rating, pain frequency, perceived sternal instability, difficulty with functional mobility, length of stay, and discharge disposition. CONCLUSIONS: In our study, the implementation of the LR approach, Keep Your Move in the Tube, had no adverse effect on outcomes 2 to 3 weeks following median sternotomy. Although no statistically significant differences were noted for all outcomes, patients with the LR approach reported less difficulty with functional mobility. IMPACT STATEMENT: These data are useful in clinical decision-making regarding alternative approaches for mobility following sternotomy.