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Wyszukujesz frazę "Zhan, Yu" wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Amino acid substitutions of His296 alter the catalytic properties of Zymomonas mobilis 10232 levansucrase
Autorzy:
Li, Shu
Chen, Ming
Li, Gang
Yan, Yong
Yu, Hai
Zhan, Yu
Peng, Zi
Wang, Jin
Lin, Min
Powiązania:
https://bibliotekanauki.pl/articles/1040841.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Zymomonas mobilis
His296
levansucrase
levan
transfructosylation activity
hydrolysis activity
Opis:
His296 of Zymomonas mobilis levansucrase (EC 2.4.1.10) is crucial for the catalysis of the transfructosylation reaction. The three-dimensional structures of levansucrases revealed the His296 is involved in the substrate recognition and binding. In this study, nine mutants were created by site-directed mutagenesis, in which His296 was substituted with amino acids of different polarity, charge and length. The substitutions of His296 with Arg or Trp retained partial hydrolysis and transfructosylation activities. The positively charged Lys substitution resulted in a 2.5-fold increase of sucrose hydrolysis. Substitutions with short (Cys or Ser), negatively charged (Glu) or polar (Tyr) amino acids virtually abolished both the activities. Analysis of transfructosylation products indicated that the mutants synthesized different oligosaccharides, suggesting that amino acid substitutions of His296 strongly affected both the enzyme activity and transfructosylation products.
Źródło:
Acta Biochimica Polonica; 2008, 55, 1; 201-206
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation of quartz from phosphorite using an imidazole ionic liquid collector and its adsorption mechanism
Autorzy:
Zhao, Yuanyuan
Xu, Wei
Mei, Guangjun
Yu, Mingming
Yang, Siyuan
He, Zhan
Powiązania:
https://bibliotekanauki.pl/articles/2146857.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reverse flotation
imidazole ionic liquid
desilication
phosphorite
quartz
Opis:
In this study, an imidazole ionic liquid (dodecyl-tri-methylimidazolium chloride) was employed as a collector to separate quartz from phosphorite. The micro-flotation experiments of a single mineral found that it had selective collecting ability for quartz than phosphorite. Mixed mineral flotation experiments confirmed that efficient separation results could be obtained using the imidazole ionic liquid as the collector. A concentrate with a 31.44% grade of phosphorite could be obtained with a 0.285 kg/Mg collector dosage at neutral pH, which was much better than the traditional collector dodecylamine. The adsorption mechanism of the imidazole ionic liquid on the surface of phosphorite and quartz was investigated by contact angle and zeta potential measurements, Fourier transform infrared and X-ray photoelectron spectroscopy analyses. These results showed that the adsorption of imidazole ionic liquid at the quartz surface was stronger than that of phosphorite, and the collector adsorbability difference between quartz and phosphorite resulted in the efficient flotation separation. Consequently, the dodecyl-tri-methylimidazolium chloride salt is an effective collector for reverse flotation of quartz from phosphorite.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 1; 159--168
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The depression mechanism on pyrite in a low-alkaline system with combined depressants : Experiment, HSC, DFT and ToF–SIMS studies
Autorzy:
Li, Suqi
Yuan, Jiaqiao
Ding, Zhan
Li, Jie
Yu, Anmei
Wen, Shuming
Bai, Shaojun
Powiązania:
https://bibliotekanauki.pl/articles/24085821.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pyrite
calcium hypochlorite
lime
depression
low alkaline system
Opis:
Depression of pyrite in a low-alkaline system has sparked soaring interests for the multi-metal sulfide minerals flotation recently. This study investigates effects of combined depressants (Ca(ClO)2 and CaO) on pyrite flotation with butyl xanthate (KBX). Micro-flotation experiments indicate that the addition of 200 mg/L combined depressants (a mass ratios of CaO to Ca(ClO) 2 of 2:3) and 1.0×10−3 mol/L KBX at pH 9.5 can effectively depresses the flotation of pyrite, and a minimum pyrite recovery rate of 12.5% is obtained. Basic thermodynamic evaluation results confirm the participation of Ca(ClO) 2 significantly decrease the negative Gibbs free energies of pyrite oxidation reaction. Besides, the calcium species (Ca(OH) 2, Ca2+ and Ca(Cl) 2) will spontaneously transform into CaCO3,and it is the ultimate dominant calcium species in the CO32- system. Density functional theory (DFT) results indicate that CaCO3 can chemically adsorb onto the pyrite surface with an adsorption energy of –671.13 kJ/mol. The O1 and Ca atoms mainly contribute to the bonding process and are responsible for the stable adsorption of CaCO3. ToF-SIMS results provide strong evidence that the combined depressants increase the amount of hydrophilic species and decrease dixanthogen adsorption onto the pyrite surface. The thickness of the whole formed hydrophilic species is approximately 50 nm. Semiquantitative amounts of hydrophilic species follow the order of hydroxy calcium>iron carbonyl>calcium carbonate. Overall, hydrophilic species repulse adsorption of dixanthogen and significantly reduce the flotation performance of pyrite.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 3; art. no. 168454
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculations of the Atomic Structure for Fe XVII Lines
Autorzy:
Zhou, Chao
Cao, Jian-Jian
Liang, Liang
Yu, Geng-Hua
Wang, Zhan-Min
He, Hua-Yue
Powiązania:
https://bibliotekanauki.pl/articles/1398915.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.30.Rj
32.70.Cs
34.80.Dp
Opis:
Energy levels, line strengths, oscillator strengths, radiative decay rates and fine structure collision strengths are presented for sixteen-times ionized iron (Fe XVII). The atomic data are calculated with the AUTOSTRUCTURE code, where relativistic corrections are introduced according to the Breit-Pauli distorted wave approach. The calculations of atomic data for 89 fine-structure levels generated from eleven configurations 2s²2p⁶, 2s²2p⁵ (3s, 3p, 3d), 2s²2p⁵ (4s, 4p, 4d, 4f) and 2s¹2p⁶ (3s, 3p, 3d) of the Ne-like Fe ion are presented. Fine structure collision strengths for transitions from the ground and the first four excited levels are presented at four electron energies: 75, 125, 175, and 250 Ry. These atomic structure data are compared with the available experimental and theoretical results.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1109-1117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seroprevalence of antibodies to classical swine fever virus and porcine reproductive and respiratory syndrome virus in healthy pigs in Hunan Province, China
Autorzy:
Yu, H.
Zhang, L.
Cai, Y.
Hao, Z.
Luo, Z.
Peng, T.
Liu, L.
Wang, N.
Wang, G.
Deng, Z.
Zhan, Y.
Powiązania:
https://bibliotekanauki.pl/articles/16539345.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
classical swine fever virus (CSFV)
porcine reproductive and respiratory syndrome virus (PRRSV)
pig
seroprevalence
antibody
Opis:
Classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Routine surveillance serology for CSF and PRRS viruses is critical to maintaining the health status of sow farms in Hunan Province, which is one of the top pig production provinces in China. The aim of our study was to investigate the serological statistics of CSF virus (CSFV) and PRRS virus (PRRSV) in Hunan Province. The cohort serum samples were collected from vaccinated and unvaccinated pigs. Our findings showed that the average rates of CSFV and PRRSV antibody seropositivity were 82.2% (95% CI: 80.1-84.3) and 84.8% (95% CI: 82.5-87.1), respectively, in the immunized group and that these rates were higher than those in the unvaccinated group (58.6% for CSFV and 47.8% for PRRSV). Additionally, the level of CSFV antibody in piglet serum declined gradually with age, whereas PRRSV-specific antibody level increased initially (1 to 2 weeks old) and then declined with age (2 to 4 weeks old). In summary, we investigated the difference in CSFV/PRRSV antibody levels among piglets at various weeks old (1 to 4 weeks) to further establish the duration of maternal immunity in piglets. In addition, routine monitoring of CSFV/PRRSV antibodies in immunized pigs was carried out to evaluate the efficacy of vaccination.
Źródło:
Polish Journal of Veterinary Sciences; 2022, 25, 3; 375-381
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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