Wyniki wyszukiwania - Biblioteka Nauki

1

Enterococcus faecalis bioflocculant enhances recovery of graphene oxide from water

100%

Xu L. , Ma R. , Sun C. , Sun D.

|

nr 6

EN

Bioflocculation is a promising method of removing GO from the water as it is safe, biodegradable, and non-secondary pollution, but few studies on effective and economic bioflocculant of GO have been reported. Accordingly, this work evaluated flocculation efficiency of an extracellular bioflocculant named MBF-21 produced by Enterococcus faecalis. Optimum culture conditions for bioflocculant production were initial medium pH of 7 and incubation temperature of 40ºC. The optimum carbon and nitrogen sources for bioflocculant production were glucose and beef extract. Results of Fourier transform infrared (FTIR) indicated the presence of carboxyl, hydroxyl, and amide groups on the MBF-21. The Zeta potential of MBF-21 analysis revealed that MBF-21 was mainly negatively charged. MBF-21 showed a significant ability in flocculation of GO, and flocculation efficiency was over 90% under neutral, acidic, and alkaline conditions, indicating that flocculation of GO was ion-independent. The conditions for flocculation of GO were optimized by response surface methodology (RSM) and determined to be an 11.57 mg/L dose and flocculation time of 75 min.

2

Prediction about ground hardening layers distribution on grinding chatter by contact stiffness

88%

Sun C. , Duan J. , Lan D. , Liu Z. , Xiu S.

|

2018

|

tom Vol. 18, no. 4

1626--1642

EN

The grinding hardening is an integrated manufacturing technology which combines the surface hardening theory and the grinding technology. However, the grinding chatter accompanies with the whole grinding hardening process. It is the existence of the grinding chatter that makes the transformation unsteady. To this end, the paper presents a three-hybrid model to investigate the relationship between the grinding chatter and the grinding hardening layers distribution. The dynamic grinding force with the analytic and numerical method is calculated firstly. Then the finite difference method (FDM) is used to obtain the dynamic temperature distribution accordingly. Thirdly, the cellular automata (CA) method is applied to calculate the transformed microstructure distribution under different chatter strengths. The study shows that the thickness of the grinding hardening layers goes up with the increase of the grinding chatter. However, the quality of the grinding hardening layers reduces with the increase of the chatter strength. In addition, the martensite content varies with different hardening layers since each layer has its own unique temperature distribution. Moreover, metallurgical experiments are conducted to validate the proposed model. The model is anticipated to be meaningful for the improvements of workpiece's mechanical properties by controlling the chatter strength in the industry manufacturing.

3

Growth and physiological responses of grape (Vitis vinifera “Combier”) to excess zinc

88%

Yang Y. , Sun C. , Yao Y. , Zhang Y. , Achal V.

Acta Physiologiae Plantarum

|

2011

|

tom 33

|

nr 4

EN

Cuttings of Vitis vinifera (cultivar Combier) were exposed to seven different zinc (Zn) concentrations (control, 3.5, 7.0, 14.0, 21.0, 28.0, and 35.0 mM) to investigate growth and physiological responses to excess amount of zinc (Zn). The apparent plant growth, as indicated by daily height growth, daily stem diameter variation, and biomass accumulation, was increased by 3.5–7.0 mM surplus Zn addition. Coupled with the increase in plant growth, grape retained low level of leaf Zn concentration, and also retained high level of leaf iron concentration due to increasing translocation of iron (Fe) from root and shoots to leaves. Leaf N and K were increased or found at a constant high level, paralleling with low oxidative pressure and enhanced catalase (CAT) activity. Moreover, plant growth was depressed under high Zn levels (>14.0 mM). Generally excess Zn was stored in the non-sensitive plant parts (roots and shoots), and it caused significant reductions of P, Fe, Mn, Cu in different parts of plant. At the same time, excess Zn caused a pronounced increase in abscisic acid concentration. Our results showed that cultivar Combier is a highly Zn-tolerant grape cultivar and could be used as pioneer plants in metalliferous site and in acidic soil of the tropical and subtropical area.

4

The molecular mechanism of fat accumulation changes in Black-Bone chickens with different energy intakes

88%

Qi R. L. , Sun C. , Yang H. L. , Zhao X. , Tao Z.

|

nr 2

EN

To investigate the molecular mechanism by which diets of different energy levels alter fat accumulation, 120 Black-Bone chickens were divided into 3 groups and fed diets with varying energy levels for six weeks (low: 3.02 Mcal/kg, moderate: 3.22 Mcal/kg, high: 3.42 Mcal/kg). The high-energy diet increased the concentration of blood lipids. Furthermore, high-energy intake inhibited the activities of several serum lipases. Histological sections showed over-synthesis of lipids in the livers of chickens fed high-energy diets. Data from western blotting and PCR analyses indicated that key factors for lipogenesis, regulatory transcription factors and fatty acid transporters, were up-regulated, while key factors for lipolysis were down-regulated. Chickens fed low-energy diets showed opposite results. In conclusion, varying energy levels of diets affect fat accumulation in Black-Bone chickens through changed expression of metabolic regulators.

5

Distribution and ecological risk assessment of heavy metals in sediments in Chinese collapsed lakes

63%

Li Y. , Liu F. , Zhou X. , Wang X. , Liu Q. , Zhu P. , Zhang L. , Sun C.

|

nr 1

EN

Surficial sediments and water (27 samples each) were collected from three representative lakes collapsed by mining activities in Huaibei, China. Contents of heavy metals (Sb, As, Cd, Pb, Zn) in both water and sediments were detected via atomic absorption spectrophotometry and atomic fluorescence spectrometry, respectively. The variation coefficient (C.V.) of each heavy metal as well as the partition coefficient (Kd) between surficial sediments and water was calculated. The ecological risks of heavy metals in collapsed lakes were assessed via geoaccumulation index (I geo), and we estimated the Pearson correlation coefficients between heavy metals. Together with the real situations around collapsed lakes, we resolved the sources of heavy metals. We found that the contents of heavy metals in water were basically below Surface Water Quality Standard I. The contents of heavy metals in the majority of sediment samples exceeded the background levels in the Yangtze River and Huai River areas, but were below the threshold effect concentration. The spatial distributions of heavy metals in surficial sediments were not uniform, as the C.V.s indicate medium variations. Analysis of Partition coefficient showed that Lieshan collapsed lake (LSH) was under severe risk. An analysis of I geo revealed gentle-medium ecological risks from Sb, As, and Cd. The classification and frequency distributions of I geo of five heavy metals indicate that the ecological risk of Cd was the largest. The ecological risk was lowest in Yangzhuang collapsed lake (YZH). These results were confirmed by analysis of C.V. and Kd. Analysis of heavy metal sources showed that the inputs of Sb and As into the three collapsed lakes were human-driven and very complex, probably due to point-source pollution, including leaching from gangue piles and industrial discharge. Cd mainly originated from non-point-source agricultural pollution, while Pb and Zn might mainly originate from natural sources.

6

Impacts of distiller’s dried grains with solubles as replacement of soybean meal plus vitamin E supplementation on production, egg quality and blood chemistry of laying hens

51%

Saeed M. , Abd E-Hack M. E. , Arif M. , El-Hindawy M. M. , Attia A. I. , Mahrose K. M. , Bashir I. , Siyal F. A. , Arain M. A. , Fazlani S. A. , Hayat K. , Sun C. , Noreldin A. E.

|

nr 3