Wyniki wyszukiwania - Biblioteka Nauki

1

Statistical Parameters Applied to the Analysis of Partial Discharge Signals in Power Cables

100%

Guo C. , Huang C. , Yao L. , Jiang X.

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tom R. 86, nr 3

282-285

EN

To analyze the partial discharge signals in power cables, statistics method is investigated according to the experiment data of defect models. Phase resolved partial discharge graphics and associated pulse distributions are acquired to show the characteristics of defect PD events. 28 statistical parameters are extracted and employed to find the different representation of the defect models in power cables. The results show that statistics method and are useful and effective in the partial discharge signals analysis.

PL

Do analzy sygnału częściowego wyładowania w kablach użyto metod statystycznych. Rozkład statystyczny impulsu wyładowania pozwala na określenie defektu. 28 parametrów statystycznych zostało wydobytych i wykorzystanych do określania rodzaju defektu w kablu. Wyniki wskazują że metody statystyczne są dobrym narzędziem analizy sygnału częściowego wyładowania.

2

Using LC-MS/MS to study dauricine pharmacokinetics and determine its bioavailability following administration in different routes

100%

Gao X. , Jiang X. , Wang L.

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tom Vol. 25, no. 2

241--256

EN

Dauricine has a variety of pharmacological properties including anti-inflammatory, anti-arrhythmic, and antihypertensive effects as well as reversing multidrug resistance (MDR) of cancer cells. While its therapeutic application is increasing, its bioavailability of different administration routes has not been studied. In the present study, we developed and validated a liquid chromatography/electrospray ionization mass spectrometry method (LC-MS/MS). Using this method, we quantified dauricine in rat plasma after administration via intravenous (i.v.) injection, per oral (p.o.), and intraperitoneal injection (i.p.). Our results indicated that this method detected plasma dauricine with a good linearity in the range of 1.95–1000.00 ng/mL (r = 0.9997). The extraction method showed an average intra- and inter-day recovery of 98.21–104.35% and 98.0–103.58%, respectively. Dauricine showed a fast absorption and widespread distribution after administration in all three tested routes. After intravenous administration (2.5, 5.0, 10.0 mg/kg), the pharmacokinetics of dauricine exhibited a first-order kinetics. In addition, dauricine showed a slow elimination with a long half-life (t1/2z) and double peaks phenomenon following p.o. and i.p. administration. Furthermore, using area under the plasma concentration-time curve (AUC), we calculated absolute bioavailability, which was over twofold higher when administered via i.p. than via p.o. administration. The newly obtained information from our study will provide important reference for dauricine dose and administration route in designing dauricine therapy for applicable diseases.

3

Constitutive model for time-dependent ratchetting of SS304 stainless steel: simulation and its finite element analysis

88%

Jiang X. , Zhu Y. , Hong J. , Zhang Y. , Kan Q.

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tom Vol. 51 nr 1

63--73

EN

Time-dependent ratchetting behaviour of SS304 stainless steel was experimentally conducted at room temperature and 973K. The material shows distinct time-dependent deformation. However, under cyclic stressing with a certain peak/valley stress hold and at 973K, more significant time-dependent inelastic behaviour was observed. Based on the Abdel-Karim-Ohno nonlinear kinematic hardening rule with the static recovery term, a time-dependent hardening rule incorporating an internal variable in the dynamic recovery term of the back stress is proposed to reasonably describe the evolution behaviour of time-dependent ratchetting with a certain peak/valley stress hold and at high temperature. Simultaneously, the proposed model is implemented into the ANSYS finite element package by User Programmable Features (UPFs). It is shown that the customized ANSYS model exhibits better performance than the reference model, especially under cyclic stressing with the certain peak/Valley stress hold and at high temperature.

PL

W pracy przedstawiono wyniki badań eksperymentalnych nad zależnym od czasu procesem zmęczeniowym typu ratcheting przeprowadzonych w temperaturze pokojowej oraz podwyższonej do 973K. Materiał wykazał wyraźnie zależną od czasu funkcję deformacji. Podczas cyklicznego obciążania przy zadanych wartościach min/max naprężeń w temperaturze 973K zaobserwowano silnie nieliniowe i zależne od czasu zachowanie się badanej stali. Do wyjaśnienia tego zjawiska, zwanego ratchetingiem zależnym od czasu, wykorzystano model umocnienia materiału oparty na nieliniowej formule kinematycznego umocnienia Abdela-Karima-Ohno ze statycznym członem odprężania. Model ten zmodyfikowano, wprowadzając wewnętrzną zmienną w dynamicznym członie odprężania przy obciążeniu powrotnym. Jednocześnie zaproponowany model wdrożono do systemu ANSYS poprzez zastosowanie pakietu User Programmable Features (UPFs). Wykazano, że taka modyfikacja systemu ANSYS charakteryzuje się lepszym działaniem w stosunku do standardowego oprogramowania. Jest to szczególnie zauważalne dla symulacji cyklicznego obciążenia stali w podwyższonej temperaturze.

4

Contrasting patterns of sun-red and shade-green leaves of Buxus microphylla in response to gradients of excess light during winter acclimation

75%

Peng J. , Jiang X. , Jia M. , Guo L. , Gao R. , Liu Y.

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nr 10

5

The activity of plasma membrane hyperpolarization-activated Ca2plus channels during pollen development of Pyrus pyrifolia

75%

Wu J. , Jin C. , Qu H. , Jiang X. , Wu J. , Xu G. , Zhang S.

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nr 3

EN

Calcium (Ca²⁺) plays crucial roles in regulation of pollen tube growth. The influx of Ca²⁺ into the pollen tube is mediated by ion channels, and the density and activity of Ca²⁺ channels in pollen plasma membranes critically determines their electrical properties. In this report, using whole-cell and single-channel patch-clamping techniques, we investigated developmental changes of hyperpolarization-activated Ca²⁺ channel activity in pear (Pyrus pyrifolia) pollen and its relationship with pollen viability. For both pollen and pollen tubes, hyperpolarization-activated Ca²⁺ channels had the same conductance and cAMP sensitivity, indicating that they were the same channels. However, the Ca²⁺ current density in pollen tube protoplasts was greater than that in pollen protoplasts. Compared with day-3 flowers’ pollen, hyperpolarizationactivated Ca²⁺ current density was significantly lower in day 0 and day 3 flowers’ pollen, which was consistent with the pollen germination and pollen tube growth, indicating that pollen protoplasts’ increased Ca²⁺ current density may have enhanced the pollen viability. During pollen tube elongation, pollen tube plasma membrane Ca²⁺ current density increased with increased length pollen tubes up to 300 µm. All of these results indicated that hyperpolarization-activated Ca²⁺ channel activity was associated with in pear pollen development and may have a causal link between Ca²⁺ channel activity and pollen viability.

6

Diel variation of water inorganic nitrogen and phosphorus during algal blooms

75%

Wang J. , Zheng B. , Kang X. , Yu H. , Li D. , Jiang X.

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nr 2

EN

Water nitrogen and phosphorus may exhibit pronounced diel changes as affected by diel temperature and DO fluctuations due to algal productivity (photosynthesis and respiration) in eutrophic lakes. Here, we used a laboratory experiment to evaluate the diel dynamics of water ammonium (NH₄⁺), nitrate (NO₃⁻), and soluble reactive phosphorus (SRP) in different periods of algal bloom in the highly polluted region of Taihu Lake, China. Results showed that diel changes of water NH₄⁺ , NO₃⁻, and SRP depended on the different periods of algal bloom. Diel variations of NH₄⁺, NO₃⁻, and SRP showed increased trends during algal decomposition, and decreased trends at the beginning of algal growth, suggesting that their diel variations were mainly controlled by algae self through nutrients released by decomposing algae or algal assimilation. However, water NH₄⁺, NO₃⁻, and SRP decreased from predawn maxima to afternoon minima and subsequently increased when Chl-a was high, which might be governed by the combined effects of algal assimilation and geochemical processes (e.g., nitrification, denitrification, and Fe-bound P cycles). Overall, the diel biogeochemical cycles of inorganic nitrogen and SRP have important implications for the accuracy of pollution assessment and provide important support for the control and management of eutrophic lakes.

7

Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw

75%

Zhang G.-W. , Zhang H.-Y. , Wang J.-F. , Zhou L. , Liu P. , Jiang X.

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tom Vol. 41, no. 1

53--58

EN

The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penet rating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities.

8

Characterization of the complete mitochondrial genome of Metastrongylus salmi (M. salmi) derived from Tibetan pigs in Tibet, China

63%

Li K. , Shahzad M. , Zhang H. , Mehmood K. , Jiang X. , Luo H. , Zhang L. , Dong X. , Li J.

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nr 2

9

RhNAC31, a novel rose NAC transcription factor, enhances tolerance to multiple abiotic stresses in Arabidopsis

63%

Ding A. , Li S. , Li W. , Hao Q. , Wan X. , Wang K. , Liu Q. , Liu Q. , Jiang X.

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nr 06

EN

Plant-specific NAM, ATAF1/2, and CUC (NAC) transcription factors serve essential functions in plant development and plant responses to environmental cues. Yet, transcription factors specific to the rose (Rosa hybrida) NAM/CUC3 subfamily are poorly understood. Here, we identify a novel NAM/CUC3-subfamily transcription factor, RhNAC31, that is associated with flower opening and can be induced by increased salt, cold, and dehydration stress treatment. RhNAC31 has a transactivation region in its C-terminal region, and its overexpression is associated with enhanced cold tolerance in Arabidopsis, conferring a higher survival rate and reduced reactive oxygen (H₂O₂ and O₂⁻) levels. Under salt stress conditions, plants overexpressing RhNAC31 displayed increased germination rates and lower levels of H₂O₂, malondiadehyde (MDA), peroxidase (POD), and superoxide dismutase (SOD). Moreover, RhNAC31 conferred enhanced drought resistance by reducing the rate of water loss through leaves. Further characterization revealed a higher sensitivity of RhNAC31 transgenic plants to abscisic acid (ABA) both during and post-germination, causing lower germination and root inhibition rates under ABA treatment. Quantitative PCR experiments showed that numerous abiotic stress-related genes were activated by RhNAC31 overexpression. Our results highlight RhNAC31 as a positive transcriptional regulator of tolerance to multiple abiotic pressures, and we conclude that RhNAC31 has potential for use in the molecular breeding of stress-tolerant crops.

10

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.

11

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.