Wyniki wyszukiwania - Biblioteka Nauki

1

New data on Late Miocene - Pleistocene ochotonids [Ochotonidae, Lagomorpha] from North China

100%

Erbajeva M. A. , Zheng S.

Acta Zoologica Cracoviensia. Ser.A Vertebrata

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2005

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tom 48A

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nr 1-2

2

A novel alkaline protease from wild edible mushroom Termitomyces albuminosus

80%

Zheng S. , Wang H. , Zhang G.

Acta Biochimica Polonica

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2011

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tom 58

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nr 2

EN

A protease with a molecular mass of 30 kDa and the N-terminal sequence of GLQTNAPWGLARSS, was isolated from fresh fruiting bodies of the wild edible mushroom Termitomyces albuminosus. The purification protocol included ion exchange chromatography on DEAE-cellulose, Q-Sepharose, SP-Sepharose and FPLC-gel filtration on Superdex 75. The protein was unadsorbed on DEAE-cellulose and Q-Sepharose, but adsorbed on SP-Sepharose. The optimal pH and temperature of the purified enzyme were 10.6 and 60°C, respectively. The enzyme was stable in the presence of 2% (v/v) Tween 80 and 4 M urea. More than 80% of the enzyme activity was retained in 2% (v/v) Triton X 100, 54% in 10 mM EDTA and 31% in 2% (w/v) SDS. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF), but not inhibited by dithiothreitol (DTT), pepstatin or lima bean trypsin inhibitor suggesting that it was a serine protease but not a trypsin-like one. The protease was inhibited by Hg2+, Cu2+, and Fe3+ ions. The Km and Vmax values of the purified enzyme for casein were 8.26 mg∙ml−1 and 0.668 mg∙ml−1∙min−1, respectively.

3

Physical purification of diatomite based on laminar-flow centrifugal separation

80%

Yang X. , Sun Z. , Zheng S.

Physicochemical Problems of Mineral Processing

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2014

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tom Vol. 50, iss. 2

705--718

EN

Natural diatomaceous earth or diatomite of good quality becomes rare and a demand for it increases every year. In this paper, we develop a novel method based on laminar-flow centrifugal separation to purify mid- and low-grade diatomite for industrial production purposes. Effects of the drum cone angle, drum speed, feeding concentration, feeding flow rate and feeding time on separation were investigated experimentally. The interdependency of these variables was studied using a response surface experiment. Operating conditions of a laminar-flow centrifugal separator were further optimized. Results showed that the feeding flow rate had a great influence on a silicon dioxide content of diatomaceous in concentrate and tailing. The optimal separation results were achieved as 87.5 wt.%, of SiO2 content of diatomaceous in concentrate and 6.98 wt.% in tailing. The optimal operating conditions included the drum cone angle of 0.0087 rad, the drum speed of 89.62 rad/s, the feeding concentration of 24.66 wt.%, the feeding flow rate of 2.33×10–4 m3/s, and the feeding time of 90 s. A scanning electron microscopy (SEM) clearly indicated that the pore blockage on the surface of diatoms was cleared out. The variation about the breakage rate of diatom shells was lower than 5% through the pilot purification production line. The characterization of original diatomite and derived products after purification were determined by X-ray diffraction (XRD). The results indicated that the impurity content of purified diatomite was improved significantly.

4

Size-dependent deflection of cross-ply composite laminated plate induced by piezoelectric actuators based on a re-modified couple stress theory

80%

Wang H. , Zheng S. , Li Z.

Archives of Mechanics

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2019

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tom Vol. 71, nr 3

177--205

EN

A size-dependent model for cross-ply composite laminated plate bonded with PZT actuators is developed by using re-modified couple stress theory (RMCST), which only uses two material length scale parameters to describe the size-dependent effect. An equivalent bending moment model and a refined model are developed by using two different ways. The analytical solution of equivalent bending moment model for simply supported composite laminated plate is obtained. The equilibrium equation of motion and corresponding boundary constraints of the refined model are established from the potential energy principle. The Ritz approximate solution of transverse deflection of the refined model indicates that the size-effect cannot be ignored in micro-scale. Numerical examples are given to account for the effect of material length scale parameters and dimensions of piezoelectric actuators on the defection of composite laminated plate.

5

Nitrogen losses in paddy field drainage modified by different water level regulations

80%

Zheng S. , Xiao M. , Miao Z.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 3

EN

Nitrogen losses from farmland, through improper drainage and rainstorm runoff, cause non-point source pollution and limit sustainable agriculture development. We determined the effects of controlled drainage (CTD) and conventional drainage (CVD) on migration responses, the transformation of nitrogen, and NH₄⁺-N and NO₃⁻-N losses. The results showed that four days after a rainstorm, compared with day one, NH₄⁺-N and NO₃⁻-N decreased by ranges of 28.7-46.7% and 7.5-47.5% in CTD, which was significantly higher than CVD. CTD also significantly reduced NH₄⁺-N and NO₃⁻-N losses in field drainage compared with CVD. NH₄⁺-N was reduced by 66.72% and NO₃⁻-N reduction was 55.56%. NH₄⁺-N contributed most to nitrogen losses, while NO₃⁻-N contributed less. Following rainstorm events, varying the water level using CVD and CTD had significant effects on NH₄⁺-N and NO₃⁻-N concentrations. The DRAINMOD-II model was used to simulate NH₄⁺-N and NO₃⁻-N levels. It indicated that the observed and simulated values of NH₄⁺-N and NO₃⁻-N concentrations in both CVD and CTD were fitted better. Lastly, the innovation of this study was that it focused on nitrogen concentrations and load changes in paddy field drainage after rainstorms, firstly using the DRAINMOD-N II model to simulate NH₄⁺-N and NO₃⁻-N concentration changes under field scale. It further validated the pollution-reduction effect under water level control in the paddy field. Also, it improved the irrigation-drainage system of paddy rice and provided a scientific basis for optimizing irrigation-drainage project design in rice irrigation district.

6

A novel method to extract vanadium from high-grade vanadium slag: non-salt roasting and alkaline leaching

71%

Liu B. , Meng L. , Zheng S. , Li M. , Wang S.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 3

657--667

EN

A new method using non-salt roasting-alkaline leaching to treat vanadium slag was proposed in this study. The V(III) in vanadium slag is oxidized to V(V) by roasting and the latter can be effectively leached out as vanadate by alkaline leaching. This method possesses distinct advantage of being able to treat high-grade vanadium slag. For the South Africa high-grade vanadium slag, the maximum vanadium recovery of 98% was achieved when the reaction conditions were roasting temperature of 850 °C, roasting time of 2 h, alkali concentration of 30 wt.%, leaching temperature of 210 °C, and leaching time of 2 h. The roasting and leaching mechanisms have been well elucidated based on the XRD and SEM analysis results. The phases transitions of vanadium slag were clearly presented. This work has laid the foundation for the industrial application of non-salt roasting-alkaline leaching and provided new insights into effective extraction of high-grade vanadium slag.

7

Ultrashort pulse propagation recording by using the transmission-type light in flight holography

71%

Fan Y. , Li J. , Zheng S. , Lu X. , Zhong X.

Optica Applicata

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2017

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tom Vol. 47, nr 2

283--294

EN

In this paper, the distortion of the reconstructed images of the propagating light pulse in transmission light-in-flight holography recording was analyzed. Based on the analysis model, for recording the wavefront more accurately, the optimized selection of relevant parameters was made. Furthermore, a cylindrical lens was introduced to correct the image distortion. Additionally, the light-in-flight recording of the wavefront changing during propagation was simulated.

8

Purification and characterization of an antibacterial protein from dried fruiting bodies of the wild mushroom Clitocybe synopica

71%

Zheng S. , Liu Q. , Zhang G. , Wang H. , Ng T. B.

Acta Biochimica Polonica

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2010

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tom 57

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nr 1

43-48

EN

A novel antibacterial protein with a molecular mass of 44 kDa has been isolated from dried fruiting bodies of the wild mushroom Clitocybe sinopica. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis showed that the protein was composed of two subunits each with a molecular mass of 22 kDa. Its N-terminal amino-acid sequence, SVQATVNGDKML, has not been reported for other antimicrobial proteins. The purification protocol included ion exchange chromatography on DEAE-cellulose, CM-cellulose and Q-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The antibacterial protein was adsorbed on all three ion exchangers. The antimicrobial activity profile of the protein against tested bacterial and fungal strains disclosed that it possessed potent antibacterial activity against Agrobacterium rhizogenes, A. tumefaciens, A. vitis, Xanthomonas oryzae and X. malvacearum with a minimum inhibitory concentration mostly below 0.6 μM. However, it had no antibacterial activity against Pseudomonas batatae, Erwinia herbicola, Escherichia coli, and Staphylococcus aureus, and no antifungal activity against Setosphaeria turcica, Fusarium oxysporum, Verticillium dahliae, Bipolaris maydis, and B. sativum. The antibacterial antivity against A. tumefaciens was stable after exposure to 20-60°C for 30 min and to pH 4-9 for 1 h.

9

Permeability of P and K-nutrient through polystyrene membrane from aqueous solutions of urea + KH2PO4

71%

Deng X. , Liu K. , Han X. , Hu X. , Zheng S.

Polish Journal of Chemical Technology

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2018

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tom Vol. 20, nr 4

113--122

EN

With the polymer-coated fertilizer as background, the permeability of P- and K-nutrient through a representative polymer membrane-polystyrene membrane were investigated by measuring their permeability in the solutions of KH2 PO4 -water and urea-KH2 PO4 water at nominal temperature of 298 K using the Ussing chamber method. To analyze and interpret the variation of permeability with solute concentration, the solubility of permeate in polymer membrane were determined experimentally and the permeate diffusion coefficient were assessed by the measurements of density and apparent molar volume of the aqueous fertilizer solutions. An interesting “increase-decrease” trend for the permeability of both phosphorous (P)-nutrient, and potassium (K)-nutrient fertilizer with permeate concentration was observed, in which the increases in permeability at low concentrations of permeate could be attributed to the increase in solubility of KH2 PO4 in polymer while the decreases in permeability at high concentrations was due to the decrease in diffusion coefficient of permeate in polymer membrane. Finally, the release kinetics of these nutrients from a PS-coated urea-KH2 PO4 compound fertilizer granule was predicted using the Shaviv’s model along with the permeability data of P- and K-nutrient generated.

10

Effect of Some Variables on the Fibre Packing Pattern in a Yarn Cross-section for Vortex Spun Yarn

71%

Zou Z. , Zheng S. , Cheng L. , Xi B. , Yao J.

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tom Vol. 22, no. 2 (104)

40--46

EN

This paper examined the influence of various parameters such as fibre fineness, yarn count, distance from the front roller nip point to the hollow spindle, nozzle pressure and yarn delivery speed on the fibre packing pattern in a yarn cross-section for vortex spun yarn. Cross-section images of vortex spun yarns were used to evaluate the fibre packing pattern. Results from different variables influencing the fibre packing pattern for vortex spun yarn were also analysed. The results indicated that the fibre fineness, yarn count, distance from the front roller nip point to the hollow spindle, nozzle pressure and yarn delivery speed are all significant parameters for yarn hairiness and fibre packing density in a vortex spun yarn cross-section.

PL

Badano wpływ grubości włókien, masy liniowej przędzy, odległości przedniej rolki do wydrążonego wrzeciona, ciśnienia w dyszy i szybkości podawania przędzy na upakowanie włókien w przekroju poprzecznym przędzy przędzionej systemem vortex. Zdjęcia przekrojów poprzecznych przędzy zostały wykorzystane dla oceny upakowania włókien. Wyniki analizy rozkładów włókien wykazały, że wszystkie badane parametry mają wydatny wpływ na upakowanie i włochatość w przędzy przędzionej systemem vortex.

11

IgG silencing induces apoptosis andsuppresses proliferation, migration and invasion in LNCaP prostate cancer cell

51%

Xu Y. , Chen B. , Zheng S. , Wen Y. , Xu A. , Xu K. , Li B. , Liu C.

Cellular and Molecular Biology Letters

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2016

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tom 21

12

High-throughput sequencing analysis of endophytic bacteria diversity in fruits of white and red pitayas from three different origins

41%

Ren Z. , Tang S. , Jiang Y. , Jiang M. , Zheng S. , Liu W. , Yang Z. , Sang S. , Chen Z. , Xia T. , Yin M.

Polish Journal of Microbiology

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2018

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tom 67

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nr 1

EN

Pitaya contains various types of polyphenols, flavonoid and vitamins which are beneficial for health and it is among the most important commercial tropical fruits worldwide. Endophytic bacteria might be beneficial for plant growth and yield. However, bacterial diversity in pitaya is poorly characterized. In this study, fruits of white and red pitayas from three different origins (Thailand, Vietnam and China) were chosen for endophytic bacteria diversity investigation by using Illumina HiSeq second-generation high-throughput sequencing technology. Large number of endophytic bacteria were detected and 22 phyla, 56 classes, 81 orders, 122 families and 159 genera were identified. Endophytic bacteria diversity was uneven among pitaya fruits from different origins and bacteria structure was different between white pitaya group and red pitaya group. Phylum Bacteroidetes, classes Bacteroidia and Coriobacteriia, orders Bacteroidales and Coriobacteriales, families Prevotellaceae, Bacteroidaceae, Ruminococcaceae, Paraprevotellaceae, Rikenellaceae, Alcaligenaceae and Coriobacteriaceae, genera Prevotella, Bacteroides, Roseburia, Faecalibacterium and Sutterella were statistically significant different species (P < 0.05) between white and red pitayas. These findings might be useful for growth improvement, fruit preservation and processing of different pitaya species from different origins.