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The quantity of human intestinal microbiota is large and diverse, its changes with age. Intestinal microbiota is closely related to the frailty of the elderly, and can be potential risk factor in the occurrence and development of frailty with different mechanisms. Therefore, the study of the relationship between frailty and intestinal microbiota in elderly patients is of great significance to the regulation of intestinal microbiota in elderly patients with frailty, so that the elderly at risk of frailty can get timely and necessary intervention and help.

Mesoporous CeO2 was synthesized by a sol-gel method using the biological renewable microcrystalline cellulose (MCC) as the template and Ce(NO3)3•6H2O as the precursor of CeO2. XRD, TEM, N2 adsorption-desorption, and XPS were used for mesoporous CeO2 characterization. The results show that CeO2 nano-particles possess an average size of 7 ~ 10 nm, and specific area of CeO2 synthesized with MCC template is approximately 5.5 times higher than CeO2 synthesized without MCC. The ozonation catalyzed by CeO2-T (with MCC) could remove 91.7% of phenol compared to 51.6% for single ozonation and 68.3% for CeO2-W (without MCC) catalyzed ozonation. The COD removal efficiency is significantly higher for ozonation with CeO2-T (69.2%) than that of CeO2-W (49.5%) or ozonation alone (21.0%). The good performance of CeO2-T is attributed to the high specific area and Ce(III)/Ce(IV) redox couple. During catalytic ozonation, the activation energy of catalytic ozonation (20.7 kJ mol−1) is much lower than that of single ozonation (54.7 kJ mol−1). [ABSTRACT FROM AUTHOR]

To further promote the water pollution control of Northeast China, to ensure the water environmental safety of Songhua river and Liaohe river, and to accelerate the harmonious development of economy, society and environment in Northeast China, the performances of 32 typical municipal wastewater treatment plants (MWWTPs) located in 13 key cities of Liaoning, Jilin and Heilongjiang were investigated and analyzed. General problems generated in the operation and management of these MWWTPs were found out, and the corresponding strategies for their stable performances were proposed. These provide guidance from the perspective of water pollution control for the sustainable development and benign circulation of the economy in Northeast China. [ABSTRACT FROM AUTHOR]

Ca 2+ is an important microbial growth factor that can affect the activity, flocculation, and sedimentation of activated sludge. In order to study the roles of Ca 2+ in the activated sludge system, the activity changes of ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were analyzed using the specific oxygen uptake rates (SOUR AOB and SOUR NOB ). The changes in composition and structure of extracellular polymeric substances (EPS) were analyzed using Fourier transform infrared spectroscopy (FTIR) and three-dimensional excitation emission fluorescence spectroscopy (3D-EEM). The effects of Ca 2+ on the nitrification activity and microbial metabolites were investigated. The results showed that when the Ca 2+ concentration increased from 0.45 mmol·L -1 to 3 mmol·L -1 , SOUR AOB and SOUR NOB increased from 6.3 mg·(g·h) -1 to 10.4 mg·(g·h) -1 and from 2.3 mg·(g·h) -1 to 3.7 mg·(g·h) -1 , respectively. The EPS concentrations increased from 68 mg·g -1 to 93 mg·g -1 , and the flocculation ability (FA) of the sludge was improved. When the Ca 2+ concentration was higher than 3 mmol·L -1 , SOUR AOB and SOUR NOB both decreased. The FA was maintained at about 30%, and the particle size of the sludge continued to increase. Based on FTIR analysis, the main components of EPS were always amino, amide Ⅰ, and carboxyl with an increase in Ca 2+ concentration. Based on EEM analysis, the composition of loosely-bound (LB)-EPS did not change, and humic acid substances appeared in the tightly-bound (TB)-EPS at low nitrification rates. Low concentrations of Ca 2+ promoted nitrification activity and flocculation of the sludge. However, high concentrations of Ca 2+ led to a decline in the sludge nitrification activity.

In order to improve the biological removal efficiency of nitrogen and phosphorus and bioflocculation performance of salt-containing wastewater, the effect of NaCl salinity on the efficiency of denitrification and phosphorus removal in the anoxic zone of an A 2 /O process was investigated. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the composition and structure of extracellular polymeric substances (EPS) in activated sludge of the anoxic zone, to discern the effect of salinity on bioflocculation. Results showed that when NaCl salinity was 0-5 g·L -1 , flocculation ability (FA) in A 2 /O anoxic zone was about 44% and the sludge particle size was 45.5 μm. EPS content increased from 52.3 mg·L -1 to 62 mg·L -1 and protein (PN)/polysaccharide (PS) remained at 2.1. When NaCl salinity increased from 10 g·L -1 to 40 g·L -1 , bioflocculation of sludge significantly decreased. FA decreased from 40% to 22% and sludge particle size decreased from 43.7 μm to 32.1 μm. EPS content increased from 76.5 mg·L -1 to 101.0 mg·L -1 and PN/PS decreased from 1.5 to 1.3. Based on FTIR analysis, with increase in salinity, the main components of EPS were always amino, amideⅠ, and carboxyl. Based on XPS analysis, increasing salinity led to charge transfer of some groups (such as C, O, and N groups) during the interaction between EPS and Na + , but its form did not change.

One strain, named as Bacillus sp. F2, of which flocculent ability can reach 84%, was separated. Flocculent genomic library was constructed. The total genomic DNA of F2 was extracted. It was partly digested by restriction enzyme Sau3AI and then was connected with carrier PUC19DNA which was totally digested by restriction enzyme BamHI and further was converted to competent cells JM109. These cells were smeared on the ampicillin substrate. After one night culture, we selected them by white-blue spot screening and constructed the flocculent genomic library. The library included 3.5 x 10(4) recons and the titre was 3.5 x 10(5) dpfu/mL. strain of Escherichia coli. positive clone FC2, which could express flocculent activity, was acquired after selection. Flocculent tests showed that the flocculent efficiency of FC2 was 90%, which was slightly higher than the original flocculent bacterium F2 and greatly higher than the competent cell JM109 (6.9%). It demonstrated that FC2's flocculent characteristic inherited from the original flocculent bacterium F2. By adopting the tapping mode AFM and Zeta-potential test, the flocculent microtopography of FC2, F2 and pure kaolin suspending solution was identified. The AFM study revealed that, compared to the kaolin suspending solution with and without F2's fermented liquid, the kaolin suspending solution which has cloning bacterium FC2's fermented liquid had larger flocculent gel and more compact spherical structure, and the surface was rough with high degree concave and convex, and had large specific surface area and strong adsorption ability to the suspending particles in the solution. After adding the fermented solution of cloning bacterium FC2 into kaolin suspending solution, the amorphous and incompact flocculent particles transformed into spherical structure which was compact and had even horizontal dimension, which indicated that the agglutinin in FC2's fermented liquid could easily take kaolin suspending particles as its adsorption core and adsorbed on its surface and the flocculent efficiency was about 90%, which gave further confirmation to the great pollution removal capability of FC2's fermented liquid. The results of Zeta-potential test illustrated that the intensity of electrovalent bond was different, resulting in various flocculent morphology, which provided significant evidences for studying flocculent mechanisms of biofloculant.