Nitrogen removal and microbial mechanisms in a novel tubular bioreactor-enhanced floating treatment wetland for the treatment of high nitrate river water.

A novel tubular bioreactor-enhanced floating treatment wetland (TB-EFTW) was developed for the in situ treatment of high nitrate river water. When compared with the enhanced floating treatment wetland (EFTW), the TB-EFTW system achieved 30% higher total nitrogen removal efficiency. Further, the average TN level of the TB-EFTW effluent was below the Grade IV requirement (1.5 mg/L) specified in Chinese standard (GB3838-2002). Microbial analysis revealed that both aerobic and anoxic denitrifying bacteria coexisted in the new system. The relative abundance of aerobic and anoxic denitrifiers were 42.69% and 22% at the middle and end of the tubular bioreactor (TB), respectively. It is reasonable to assume that effective nitrogen removal can mainly be attributed to the addition of solid carbon source and the spatial difference in DO distribution (oxic-anoxic areas in sequence) inside the TB. The initial investment cost and operating costs associated with the TB-EFTW system are approximately 14,000 and 3500 yuan per 1000 m3 river water, respectively. Considering its low cost, minimal maintenance requirements, and effective nitrogen removal, this newly developed system can be regarded as a promising technology for treating high nitrate river water. PRACTITIONER POINTS: A novel TB-EFTW system was developed to upgrade traditional in situ treatment techniques. The TB-EFTW could achieve 30% higher nitrogen removal efficiency than EFTWs. Both aerobic and anoxic denitrifying bacteria coexisted in the system. The system shows better technical and economic performance compared with routine techniques.

Effects of an individualized nutritional intervention on the prognosis of patients with liver failure.

BACKGROUND AND OBJECTIVES: Patients with liver failure often have energy metabolism disorders and malnutrition, which lead to poor prognosis, rendering nutritional interventions essential. METHODS AND STUDY DESIGN: Individualized nutritional interventions were offered according to the resting energy expenditure (REE) of patients with liver failure, and the patients were followed up for 180 days. RESULTS: Sixty patients with liver failure were enrolled and grouped by their prognosis and energy intake. Model for end-stage liver disease (MELD) score and body fat mass of the nonsurvival group were significantly higher than those of the survival group (p<0.05), whereas the mean energy intake/REE (MEI/REE) and mean respiratory quotient (RQ) of the nonsurvival group were significantly lower than those of the survival group (p<0.01). Prediction REE (PredREE) was calculated using the Harris-Benedict formula. Most patients in the nonsurvival and survival groups had hypometabolic (REE/PredREE <0.9) and normal metabolic status (0.9

Effects of an individualized nutrition intervention on the respiratory quotient of patients with liver failure.

BACKGROUND AND OBJECTIVES: Malnutrition and energy metabolism disorders are characterized by a low respiratory quotient in patients with liver failure and often lead to poor prognosis. Therefore, early nutrition interventions are crucial for patients with liver failure to ameliorate abnormal metabolic status and malnutrition. This study explored the effect of an individualized nutrition intervention on the respiratory quotient of patients with liver failure. METHODS AND STUDY DESIGN: An individualized 2-week nutrition intervention was conducted on patients with nutritional risk caused by liver failure according to patient resting energy expenditure. Patients were separated into two groups for further analysis according to whether their energy intake reached 1.2 times their resting energy expenditure. RESULTS: Fifty-two patients with nutritional risk caused by liver failure were enrolled. Their average respiratory quotient was 0.79 (0.76-0.84) at the baseline. Patients with an energy intake of >=1.2 times their resting energy expenditure had a higher respiratory quotient and lower scores on the model for endstage liver disease and Child-Pugh test than those with an energy intake of <1.2 times their resting energy expenditure at weeks 1 and 2 after the intervention. Moreover, no significant differences were observed between the two groups at the baseline. Respiratory quotient was negatively correlated with the model for end-stage liver disease and Child-Pugh scores. CONCLUSIONS: Individualized nutrition interventions with an energy intake >=1.2 times the patient's resting energy expenditure can effectively improve the respiratory quotient and reduce disease severity in patients with nutritional risk caused by liver failure.

A novel pilot-scale tubular bioreactor-enhanced floating treatment wetland for efficient in situ nitrogen removal from urban landscape water: Long-term performance and microbial mechanisms.

In order to strengthen in situ nitrogen removal of urban landscape water, a novel pilot-scale tubular bioreactor-enhanced floating treatment wetland (TB-EFTW) was constructed, and the long-term performance and responsible microbial mechanisms were investigated in this study. The results showed that the system could remove 81.5% nitrogen from the landscape water after 240 days' operation. Moreover, the contribution rate of plant absorption to nitrogen was low (8.3%), which indicated that microbial biotransformation rather than plant absorption played a more key role in nitrogen removal in TB-EFTW system. The declining dissolved oxygen (DO) concentration along the axial direction of tubular bioreactor (TB) resulted in the sequential bacterial community of nitrifying, aerobic denitrifying, and anoxic denitrifying bacteria in the front, middle, and final part of TB. High-throughput sequencing results demonstrated that the internal environment of the system realized the coexistence of nitrifying, aerobic denitrifying and anoxic denitrifying process. The reason was mainly because that oxic-anoxic (O-A) areas were formed in sequence along the axial direction of tubular bioreactor. Overall, a unique advantage in nitrogen removal was achieved in TB-EFTW, which could provide important references for in situ treatment of urban landscape water. PRACTITIONER POINTS: TB-EFTW strengthened nitrogen removal for in situ urban landscape water treatment. Microbial conversion played a key role in nitrogen removal of the TB-EFTW system. The unique distribution of oxic-anoxic (O-A) areas was formed in sequence along the TB. Nitrification, aerobic, and anoxic denitrification were synergistically involved in the TB.

Synthesis of the system modeling and signal detecting circuit of a novel vacuum microelectronic accelerometer.

A novel high-precision vacuum microelectronic accelerometer has been successfully fabricated and tested in our laboratory. This accelerometer has unique advantages of high sensitivity, fast response, and anti-radiation stability. It is a prototype intended for navigation applications and is required to feature micro-g resolution. This paper briefly describes the structure and working principle of our vacuum microelectronic accelerometer, and the mathematical model is also established. The performances of the accelerometer system are discussed after Matlab modeling. The results show that, the dynamic response of the accelerometer system is significantly improved by choosing appropriate parameters of signal detecting circuit, and the signal detecting circuit is designed. In order to attain good linearity and performance, the closed-loop control mode is adopted. Weak current detection technology is studied, and integral T-style feedback network is used in I/V conversion, which will eliminate high-frequency noise at the front of the circuit. According to the modeling parameters, the low-pass filter is designed. This circuit is simple, reliable, and has high precision. Experiments are done and the results show that the vacuum microelectronic accelerometer exhibits good linearity over -1 g to +1 g, an output sensitivity of 543 mV/g, and a nonlinearity of 0.94 %.