Wyniki wyszukiwania - Biblioteka Nauki

1

The combined effects of water deficit and heat stress on physiological characteristics of endangered Nouelia insignis

100%

Zheng Y. , Xia Z. , Ma H. , Yu Z.

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2019

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tom 41

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nr 11

EN

Dry-hot valley is characterized by water deficit and heat stress which often occur simultaneously in the field. Nouelia insignis has become endangered and natural regeneration of the species in the dry-hot valley is limited. Seedlings subjected to each water deficit treatment (achievement by withholding irrigation for 0, 3 and 6 days, respectively) were randomly divided into three groups and transferred to climate chambers set at 25, 40 and 50 °C for 1 h, respectively. Leaf relative water content, photosynthetic activity and maximum quantum yield of photosystem II (Fv/Fm) determined after 1 day of recovery were decreased significantly, but pigment content and catalase (CAT) activity increased significantly under severe water deficit or extreme heat. Soluble sugar content increased significantly under severe water deficit or moderate heat stress. Significant interactive effects between water deficit and heat were found in leaf relative water content, Fv/Fm, non-photochemical quenching coefficient (NPQ), CAT activity and soluble sugar content. Fv/Fm of seedlings treated at combination of 50 °C and water deficit did not recover to the original level after 1 day of recovery. In conclusion, both severe water deficit and heat stress could lead to water loss of leaves and adversely affect plant metabolic activities of N. insignis. Particularly, the effects were aggravated when severe water deficit and extreme heat occurred simultaneously. Water deficit and heat, particularly their combination, might be the key factors which limited natural regeneration of N. insignis in the dry-hot valley.

2

Signaling pathways and apoptosis-lesson learned from cultured cortical neurons

88%

Hetman M. , Chlystun M. , Cavanaugh J. , Kanning K. , Xia Z.

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nr 3

3

Modeling and current control strategy for a medium-voltage cascaded multilevel statcom with LCL filter

88%

Zhao X. , Shi L. , Chen L. , Xia Z. , Bendre A. R.

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2015

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tom Vol. 95, nr 1

1--13

EN

The Static Synchronous Compensator (STATCOM a.k.a. SVG) is widely used to regulate dynamic reactive power and to solve dynamic voltage stability problems. Modeling shows that a cascaded STATCOM, which is composed of several cascaded H-bridges, not only has strong coupling characteristics when an LCL filter is added but it is also a non-linear, multivariable system. Therefore, its practical design and application are dicult to implement. In this paper an internal decoupling control algorithm is introduced to provide independent control of the active and reactive currents. Decoupling control algorithms are proposed, and models and simulation of the decoupling are provided. We describe the setting up of a simulation and experiments with a cascaded STATCOM based on combined circuit topology with a multi-field programmable gate array (FPGA), and double-loop control algorithms with a current inner loop, and a capacitor voltage outer loop. To provide control of the current inner loop, proportional-integral (PI) and resonant controllers are used, having the control ability to cancel harmonics while compensating for the reactive power. This paper presents new current-tracing control models that compensate for the fundamental current and eliminate selective harmonics by adopting a d-q synchronous reference frame, and a discrete Fourier transform (DFT). Voltage balance is realized by introducing modulation wave distribution strategies. Furthermore, both simulation and experiments are employed to verify the feasibility and eectiveness of the control strategy.

4

Scale Effect on Jute/Cotton Fibres and their Blended Yarns

88%

Xia Z. , Yu J. , Cheng L. , Liu L. , Wang W.

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tom Vol. 17, no. 4 (75)

43--45

EN

The tenacities of jute and cotton fibres as well as their blended yarns at different gauge lengths were investigated in this paper. Based on Weibull distribution, the tenacity of the fibres and their blended yarns at a testing gauge length from 5 mm to 500 mm was studied. The tenacity of jute and cotton fibres is more dependent on the gauge length than that of their blended yarns. The blended yarn tenacity with a high jute content is more sensitive to the gauge length than that of a yarn with a low jute content.

PL

Badano wytrzymałość włókien bawełnianych i jutowych oraz przędz wykonanych z mieszanek tych włókien przy różnych długościach zrywanych próbek zmieniając je od 5 mm do0 500mm. Wytrzymałość włókien i przędz analizowano na podstawie rozkładu Weibulla. Stwierdzono, że wytrzymałość włókien jest bardziej zależna od długości zrywanej próbki niż przędz mieszankowych, jak również , że zwiększenie zawartości juty w przędzy bardziej uzależnia wytrzymałość od długości próbki.

5

Glycogen synthase kinase-3Beta as a target for neuroprotective signaling pathways

88%

Hetman M. , Chlystun M. , Higgins M. , Cavanaugh J. , Xia Z.

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nr 3

6

In vivo cardioprotective effects and pharmacokinetic profile of N-propyl caffeamide against ischemia reperfusion injury

75%

Cheng Y.-Y. , Luo D. , Xia Z. , Tse H.-F. , Li X. , Rong J.

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nr 2

7

Seroepidemiology of Toxoplasma gondii in pet dogs and cats in Beijing, China

75%

Yu J. , Ding J. , Xia Z. , Lin D. , Li Y. , Jia J. , Liu Q.

Acta Parasitologica

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2008

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tom 53

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nr 3

EN

Sera from 534 pet dogs and 335 pet cats from Beijing (China) were tested for anti-Toxoplasma gondii antibodies using an enzyme-linked immunosorbent assay or the latex agglutination test. The seropositivity by year, season, sex and age was analysed. Overall, 128 dogs (24.0%) and 50 cats (14.9%) had antibodies to T. gondii. When analysed by season, the highest seroprevalence was found in spring for dogs (31.3%) and cats (25.1%), and the differences in seroprevalence by season was statistically significant in cats (P<0.01) but not in dogs. The seroprevalence in male dogs (23.7%) and cats (15.1%) were slightly higher than their female counterparts (18.0% in dogs and 12.3% in cats). There was no obvious pattern of seropositivity or significant difference in different age groups in dogs or cats; nonetheless, a high proportion of dogs at 4 years of age were positive to T. gondii (31.8%) while cats with relatively high seropositivity rates were at 1 or 3.4 years of age (13.14%).

8

The response of Mo-hydroxylases and abscisic acid to salinity in wheat genotypes with differing tolerances

63%

Xu H. , Zhai J. , Liu Y. , Cheng X. , Xia Z. , Chen F. , Cui D. , Jiang X.

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nr 5

EN

The differential responses of the wheat cultivars Shi4185 and Yumai47 to salinity were studied. The higher sensitivity of Yumai47 to salinity was linked to a greater growth reduction under salt stress, compared to more salt-tolerant Shi4185. Salinity increased the Na⁺, proline and superoxide anion radical (O₂⁻) contents in both cultivars. Leaf Na⁺ content increased less in the more salttolerant cultivar Shi4185 than salt-sensitive Yumai47. The proline content increased more significantly in Shi4185 than Yumai47; on the contrary, superoxide anion radical content increased less in Shi4185 than Yumai47. This data indicated that wheat salinity tolerance can be increased by controlling Na⁺ transport from the root to shoot, associated with higher osmotic adjustment capability and antioxidant activity. Although salinity increased aldehyde oxidase (AO) activity and abscisic acid (ABA) content in the leaves and roots of both cultivars following the addition of NaCl to the growth medium, AO and ABA increased more in the salt-sensitive cultivar Yumai47 than the more salt-tolerant cultivar Shi4185. Xanthine dehydrogenase (XDH) activity in the leaves of both cultivars increased with increasing concentrations of NaCl; however, leaf XDH activity increased more significantly in Yumai47 than Shi4185. Root XDH activity in Shi4185 decreased with increasing NaCl concentrations, whereas salinity induced an increased root XDH activity in Yumai47. The involvement of AO and XDH enzymatic activities and altered ABA content in the response mechanisms of wheat to salinity are discussed herein.

9

Ca2plus/Hplus exchange in the plasma membrane of Arabidopsis thaliana leaves

63%

Zhai J. , Xu H. , Cong X. , Deng Y. , Xia Z. , Huang X. , Hao G. , Jiang X.

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nr 01

EN

A large number of plant Ca2+/H+ exchangers have been identified in endomembranes, but far fewer have been studied for Ca2+/H+ exchange in plasma membrane so far. To investigate the Ca2+/H+ exchange in plasma membrane here, inside-out plasma membrane vesicles were isolated from Arabidopsis thaliana leaves using aqueous two-phase partitioning method. Ca2+/H+ exchange in plasma membrane vesicles was measured by Ca2+-dependent dissipation of a pre-established pH gradient. The results showed that transport mediated by the Ca2+/H+ exchange was optimal at pH 7.0, and displayed transport specificity for Ca2+ with saturation kinetics at Km = 47 lM. Sulfate and vanadate inhibited pH gradient across vesicles and decreased the Ca2+-dependent transport of H+ out of vesicles significantly. When the electrical potential across plasma membrane was dissipated with valinomycin and potassium, the rate of Ca2+/H+ exchange increased comparing to control without valinomycin effect, suggesting that the Ca2+/H+ exchange generated a membrane potential (interior negative), i.e. that the stoichiometric ratio for the exchange is greater than 2H+:Ca2+. Eosin Y, a Ca2+-ATPase inhibitor, drastically inhibited Ca2+/H+ exchange in plasma membrane as it does for the purified Ca2+-ATPase in proteoliposomes, indicating that measured Ca2+/H+ exchange activity is mainly due to a plasma membrane Ca2+ pump. These suggest that calcium (Ca2+) is transported out of Arabidopsis cells mainly through a Ca2+-ATPase-mediated Ca2+/H+ exchange system that is driven by the proton-motive force from the plasma membrane H+-ATPase.