Microbial community changes and metabolic pathways analysis during waste activated sludge and meat processing waste anaerobic co-digestion.

Waste activated sludge (WAS) and meat processing waste (MPW) were acted as co-substrates in anaerobic co-digestion (AcD), and biochemical methane potential (BMP) test was carried out to investigate the methane production performances. Microbial community structure and metabolic pathways analyses were conducted by 16S rRNA high-throughput sequencing and functional prediction analysis. BMP test results indicated that AcD of 70% WAS+30% MPW and 50% WAS+50% MPW (VS/VS) could significantly improve methane yield to 371.05 mL/g VS and 599.61 mL/g VS, respectively, compared with WAS acting as sole substrate (191.87 mL/g VS). The results of microbial community analysis showed that Syntrophomonas and Petrimonas became the dominant bacteria genera, and Methanomassiliicoccus and Methanobacterium became the dominant archaea genera after MPW addition. 16S functional prediction analysis results indicated that genes expression of key enzymes involved in syntrophic acetate oxidation (SAO), hydrogenotrophic and methylotrophic methanogenesis were up-regulated, and acetoclastic methanogenesis was inhibited after MPW addition. Based on these analyses, it could be inferred that SAO combined with hydrogenotrophic and methylotrophic methanogenesis was the dominant pathway for organics degradation and methane production during AcD. These findings provided systematic insights into the microbial community changes and metabolic pathways during AcD of WAS and MPW.

Synergistic effects of peracetic acid and free ammonia pretreatment on anaerobic fermentation of waste activated sludge to promote short-chain fatty acid production for polyhydroxyalkanoate biosynthesis: Mechanisms and optimization.

Peracetic acid (PAA) combined with free ammonia (FA) pretreatment can be utilized to promote anaerobic fermentation (AF) of waste activated sludge (WAS) to produce short-chain fatty acids (SCFAs), and the resulting SCFAs are desirable carbon sources (C-sources) for polyhydroxyalkanoate (PHA) biosynthesis. This work aimed to determine the optimum conditions for PAA + FA pretreatment of sludge AF and the feasibility of using anaerobic fermentation liquor (AFL) for PHA production. To reveal the mechanisms of integrated pretreatment, the impacts of PAA + FA pretreatment on different stages of sludge AF and changes in the microbial community structure were explored. The experimental results showed that the maximum SCFA yield reached 491.35 ± 6.02 mg COD/g VSS on day 5 after pretreatment with 0.1 g PAA/g VSS +70 mg FA/L, which was significantly greater than that resulting from PAA or FA pretreatment alone. The mechanism analysis showed that PAA + FA pretreatment promoted sludge solubilization but strongly inhibited methanogenesis. According to the analysis of the microbial community, PAA + FA pretreatment changed the microbial community structure and promoted the enrichment of bacteria related to hydrolysis and acidification, and Proteiniclasticum, Macellibacteroides and Petrimonas became the dominant hydrolytic and acidifying bacteria. Finally, after alkali treatment, the AFL was utilized for batch-mode PHA production, and a maximum PHA yield of 55.05 wt% was achieved after five operation periods.

Layered double hydroxides for phosphorus recovery from lipid-rich waste anaerobic fermentation liquor.

This study aimed to extract orthophosphate (ortho-P) from lipid-rich waste AF liquor (AFL) by Mg/Al layered double hydroxides (Mg/Al LDHs) adsorption, evaluate the influence of carbonate and investigate adsorption mechanisms. The carbonate influence experiment using synthetic P-rich wastewater indicated that low carbonate level was favorable for P extraction by LDHs. And then, real AFL rich in volatile fatty acids (VFAs), carbonate and ortho-P was applied as adsorbate to explore the Mg/Al LDHs adsorption performance. Experimental results indicated that 4 g/L Mg/Al LDHs could extract 88.3% of ortho-P from the AFL with low carbonate level (4829.83 mg CaCO3/L), and the adsorption quantity was 62.99 mg P/g LDHs, however, negligible VFAs were extracted. Kinetics and mechanisms analysis indicated that adsorption of P onto Mg/Al LDHs was a rapid physiochemical process, including ion exchange and surface adsorption. Finally, the nutrients release test confirmed the slow-release property of intercalated P.

Robust Time-Delay Feedback Control of Vehicular CACC Systems with Uncertain Dynamics.

This paper proposes a new, robust time-delay cooperative adaptive cruise control (CACC) approach for vehicle platooning systems with uncertain dynamics and varying communication delay. The uncertain CACC models with perturbed parameters are used to describe the uncertain dynamics of the vehicle platooning system. By combining the constant time headway strategy and predecessor-following communication topology, a set of robust delay feedback controllers is designed for the uncertain vehicle platoon with varying communication delay. Then, the set of CACC controllers is computed by solving some linear matrix inequalities, which further establish the robust (string) stability of the uncertain platooning system with the varying communication delay. The co-simulation experiment of CarSim and Simulink with a group of a seven-car platoons and varying velocity is used to demonstrate the effectiveness of the presented method.

Secure State Estimation for Motion Monitoring of Intelligent Connected Vehicle Systems.

This paper considers the state estimation problem of intelligent connected vehicle systems under the false data injection attack in wireless monitoring networks. We propose a new secure state estimation method to reconstruct the motion states of the connected vehicles equipped with cooperative adaptive cruise control (CACC) systems. First, the set of CACC models combined with Proportion-Differentiation (PD) controllers are used to represent the longitudinal dynamics of the intelligent connected vehicle systems. Then the notion of sparseness is employed to model the false data injection attack of the wireless networks of the monitoring platform. According to the corrupted data of the vehicles' states, the compressed sensing principle is used to describe the secure state estimation problem of the connected vehicles. Moreover, the L1 norm optimization problem is solved to reconstruct the motion states of the vehicles based on the orthogonaldecomposition. Finally, the simulation experiments verify that the proposed method can effectively reconstruct the motion states of vehicles for remote monitoring of the intelligent connected vehicle system.

Advanced treatment of biologically treated coking wastewater by persulfate oxidation with magnetic activated carbon composite as a catalyst.

Advanced treatment of biologically treated coking wastewater (BTCW) using persulfate (PS) oxidation with magnetic activated carbon composite (CuFe2O4:AC w/w ratio of 1:1.5, denoted as 1.5-MACC) as a green catalyst was evaluated at ambient temperature (30 °C). Effects of PS (K2S2O8) and 1.5-MACC doses on PS decomposition and total organic carbon (TOC) removal in BTCW were also studied during 360 min. The results showed that the 1.5-MACC/PS system has a much better performance on TOC removal in BTCW than only 1.5-MACC or PS system. PS decomposition and TOC removal follow first-order kinetics in the 1.5-MACC/PS system. The optimum condition of the 1.5-MACC/PS system to treat BTCW is with a K2S2O8 dose of 4 g L-1 and 1.5-MACC dose of 5 g L-1. Under this condition, TOC in the PS oxidation effluent is 20.4 mg L-1 with a removal efficiency of 85.4%. TOC removal is a synergistic effect of adsorption and oxidation. TOC oxidation is due to the generation of ·SO4- via the activation of PS by CuFe2O4 impregnated AC. The gas chromatography-mass spectrometry (GC-MS) analysis revealed that phenol compounds and esters were removed significantly by the 1.5-MACC/PS system. When 1.5-MACC was used for the fourth time in the 1.5-MACC/PS system, the removal ratio of TOC was still over 62.2% in 360 min reaction. Thus, the 1.5-MACC/PS system has a potential practical application in treatment of BTCW.

Simultaneous recovery of short-chain fatty acids and phosphorus during lipid-rich anaerobic fermentation with sodium hydroxide conditioning.

Anaerobic fermentation (AF) could achieve simultaneous recovery of short-chain fatty acids (SCFAs) and phosphorus (P) when waste activated sludge (WAS) and meat processing waste (MPW) act as co-substrate. However, long-chain fatty acids, the degradation intermediates of lipids, always inhibit anaerobic microbial activity. Therefore, sodium hydroxide (NaOH) conditioning was applied to improve the lipid-rich AF performance in this study. The results demonstrated that 96% WAS (v/v) with NaOH addition that remaining at pH 7.5 could achieve the maximum SCFAs yield (1180.05 mg/g VSfed) at 12 d, and ortho-P content in the AF liquor (AFL) was much more than that of without NaOH addition. Anaerovibrio and Aminobacterium, one kind of lipolytic and proteolytic bacteria, respectively, became the major genus in the lipid-rich AF system. 86% of P in the AFL from 96% WAS + pH 7.5 reactor was recovered through vivianite crystallization method, with 91% of SCFAs remaining in the post-AFL. Meanwhile, analysis results verified vivianite formation in the P precipitate products. Overall, this study provided a new idea to achieve SCFAs and P simultaneous recovery from WAS and MPW through AF with NaOH conditioning and vivianite crystallization.

CLFs-based optimization control for a class of constrained visual servoing systems.

In this paper, we use the control Lyapunov function (CLF) technique to present an optimized visual servo control method for constrained eye-in-hand robot visual servoing systems. With the knowledge of camera intrinsic parameters and depth of target changes, visual servo control laws (i.e. translation speed) with adjustable parameters are derived by image point features and some known CLF of the visual servoing system. The Fibonacci method is employed to online compute the optimal value of those adjustable parameters, which yields an optimized control law to satisfy constraints of the visual servoing system. The Lyapunov's theorem and the properties of CLF are used to establish stability of the constrained visual servoing system in the closed-loop with the optimized control law. One merit of the presented method is that there is no requirement of online calculating the pseudo-inverse of the image Jacobian's matrix and the homography matrix. Simulation and experimental results illustrated the effectiveness of the method proposed here.

[Relationship between left ventricular diastolic function and plasma brain natriuretic peptide concentration during severe pregnancy-induced hypertension syndrome].

OBJECTIVE: To evaluate the relationship between the left ventricular diastolic function and plasma level of plasma brain natriuretic peptide (BNP) among patients with pregnancy-induced hypertension (PIH) syndrome. METHODS: The left ventricular diastolic function was evaluated by Doppler echocardiography, and plasma BNP level was tested by radioimmunoassay among 36 pregnant women with severe PIH, 32 normal pregnant women, and 21 normal non-pregnant women of childbearing age. RESULTS: The parameters such as peak mitral flow velocity in early diastole (E), E-wave velocity-time integral (EVTI), the ratio of peak mitral flow velocity in early diastole and peak A-wave velocity in late diastole (E/A), peak pulmonary venous diastolic forward flow velocity (D) and D-wave velocity-time integral (DVTI) of the 36 severe PIH patients were significantly lower than those of the 32 normal pregnant women and those of the 21 normal non-pregnant women of child-bearing age. But the parameters such as A, A-wave velocity integral (AVTI), and peak pulmonary venous diastolic forward flow velocity (AR) were significantly higher than those of the normal pregnant women and those of the normal non-pregnant women of child-bearing age. E/A ratio, D and DVTI of the normal pregnant women were significantly lower than those of the normal non-pregnant women of child-bearing age, however, A, AVTI, S/D, and AR were significantly higher than those of the normal non-pregnant women of child-bearing age. The BNP concentration of the normal pregnant women was significantly higher than that of the normal non-pregnant women of childbearing age, but significantly lower than that of the severe PIH patients. There were significant correlations between left ventricular diastolic function variables (E/A ratio and AR) and BNP concentration in normal pregnant women and in PIH patients. CONCLUSION: The left ventricular diastolic function is slightly damaged in normal pregnant women and significantly damaged in patients with severe PIH. The plasma BNP level of pregnant women can become an excellent index to predict their left ventricular diastolic function.

[Encoding genes and genotypes of gamma-lactamases produced by a multiple resistant Klebsiella pneumoniae]

OBJECTIVE: To determine the sequence of gene for encoding beta-lactamase produced by Klebsiella pneumoniae E3 isolated from Jiaxing Area in Zhejiang Province. METHODS The Klebsiella pneumoniae strain E3 was identified as an ESBLs-producing bacterium by inhibitor-potentiated broth dilution test. The gene encoding gamma-lactamase of the strain was amplified by PCR. The purified PCR product was cloned and sequenced by Sanger's dideoxy chain termination composition method. RESULTS The Klebsiella pneumoniae strain E3 produced both TEM and SHV gamma lactamases. The SHV encoding gene had 812 nucleotide residues responsible for encoding SHV-11 gamma-lactamase and the TEM encoding gene had 973 nucleotide residues responsible for encoding TEM-1 gamma-lactamase. CONCLUSION The Klebsiella pneumoniae strain E3 isolated from a patient in Jiaxing Area in Zhejiang Province is able to produce both TEM-1 and SHV-11 gamma-lactamases.