Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 11

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

The gomphotheriid mammal Platybelodon from the Middle Miocene of Linxia Basin, Gansu, China

100%
Wang S., He W., Chen S.
Acta Palaeontologica Polonica
|
2013
|
tom 58
|
nr 2
In this paper, we report on abundant fossils of Platybelodon from the Middle Miocene of the Linxia Basin, China. Most of the fossils were discovered at two localities (Laogou and Zengjia) in the upper Middle Miocene Hujialiang Formation, and possess derived characters for the genus, including a relatively slender upper incisor, the development of a transverse ledge on the narrowest part of the mandibular symphysis, narrow, elongate and hypsodont third molars, the development of fourth loph(id)s on the second molars, and the development of small enamel conules and cementum in the interloph(id)s. Following comparisons with other Eurasian platybelodonts, we assign these remains to Platybelodon grangeri, and demonstrate that they are morphologically intermediate between P. grangeri from the Tunggurian localities of Tarim Nor and Platybelodon Quarry in Inner Mongolia. We suggest that the locality of Laogou may be younger than that of Zengjia, based on the occurrence of platybelodonts showing a suite of more derived characters. In addition, we assign two further specimens of Platybelodon from the lower Middle Miocene Dongxiang Formation of the Linxia Basin to Platybelodon danovi, owing to their retention of plesiomorphic characters distinguishing them from other Linxia Platybelodon fossils. Based on a cladistic analysis, we propose an evolutionary sequence of platybelodonts in Eurasia, and discuss potential functional adaptations.
2

Fundamental immunology of skin transplantation and key strategies for tolerance induction

100%
Zhou J., He W., Luo G., Wu J.
Archivum Immunologiae et Therapiae Experimentalis
|
2013
|
tom 61
|
nr 5
3

Morphology and cell division of the little known freshwater ciliate Uroleptus cf. magnificus (Kahl, 1932) Olmo, 2000 (Hypotricha, Uroleptidae), and list of published names in Uroleptus Ehrenberg, 1831 and Paruroleptus Wenzel, 1953

88%
He W., Shi X., Shao C., Chen X., Berger H.
Acta Protozoologica
|
2011
|
tom 50
|
nr 3
4

In vitro co-stimulation of anti-tumor activity by soluble B7 molecules

88%
He W., Hu Z.-B., Liu F., Feng X.-Q., Zou P.
Acta Biochimica Polonica
|
2006
|
tom 53
|
nr 4
5

Materials separation from waste liquid crystal displays using combined physical methods

88%
Zhuang X., He W., Li G., Huang J., Ye Y.
Polish Journal of Environmental Studies
|
2012
|
tom 21
|
nr 6
With the liquid crystal displays (LCDs) being widely used in televisions, notebooks, and mobile phones, etc., large quantities of LCDs are entering into their end-of-life stage for treatment. If not treated properly, a loss of resources and undesirable impacts on the environment and human health can occur. In order to treat the waste LCDs in an efficient and environmentally friendly way, a combined process of physical methods was proposed to separate and recover materials from waste LCDs in the present study. On the basis of primary disassembly, two key processes (including liquid crystals removal and the recovery of polarizer and glass) were studied. Liquid crystals were removed from the panel glass by dissolving in isopropyl alcohol solution (16.7 vol.%) assisted with ultrasound. Recovery of polarizer and glass was achieved through mechanical crushing and gravity concentration. Results show that approximately 100 wt.% of liquid crystals were removed after dissolving for 45 min at 60ºC. Up to 79.7 wt.% of polarizer was separated from glass and its average content in the recovered product was 90.3 wt.%.
6

Physiological adaptations of Elymus dahuricus to high altitude on the Qinghai-Tibetan Plateau

76%
Cui G., Ji G., Liu S., Li B., Lian L., He W., Zhang P.
Acta Physiologiae Plantarum
|
2019
|
tom 41
|
nr 07
The harsh natural environment on the Qinghai–Tibetan Plateau has a detrimental effect on the growth of vegetation. Elymus dahuricus, a widely distributed perennial herb on the Qinghai–Tibetan Plateau, is highly adapted to alpine regions. To unveil the mechanism of E. dahuricus adaptation to high altitude on the Qinghai–Tibetan Plateau, the relative photosynthetic characteristics and physiological indexes of wild E. dahuricus collected from different elevations in Huangzhong County and Minhe County of Qinghai Province were investigated. Increases in the maximum photochemical efficiency (Fv/Fm), potential activity (Fv/Fo), non-photochemical quenching (NPQ), total carotenoids content (Car), chlorophyll a to chlorophyll b ratio (Chl a/b) and total carotenoids to chlorophyll ratio (Car/Chl) were accompanied by decreases in photochemical quenching coefficient (qP), effective photochemical quantum yield of PSII (Y(II)) and chlorophyll a (Chl a) and chlorophyll b (Chl b) contents. Increases in Fv/Fm and Fv/F0 with altitude indicate that the photosynthetic capacity can be maintained with increases in altitude. As a photoprotective mechanism, decreases in chlorophyll content could lead to a reduction in the absorption of high energy light by leaves; therefore, the photosynthetic capacity of E. dahuricus was maintained on the Qinghai–Tibetan Plateau. Furthermore, the increasing malondialdehyde content along altitudinal gradients indicated that the alpine environments had an adverse effect on E. dahuricus growth. The increase in superoxide dismutase, peroxidase and catalase activities reflected a higher reactive oxygen species scavenging capacity, and the increases in soluble sugar and proline contents increased the osmotic adjustment substance contents, suggesting that the reactive oxygen species scavenging ability and osmotic pressure regulation play roles in maintaining the normal growth of E. dahuricus. In conclusion, the high altitude on the Qinghai–Tibetan Plateau negatively affected E. dahuricus growth, and the adaptation mechanism and survival strategies of E. dahuricus were ascribed to the comprehensive effects of photosynthetic capacity, reactive oxygen species scavenging and osmotic adjustments.
7

Antioxidative responses to different altitudes in leaves of alpine plant Polygonum viviparum in summer

76%
Wang Y., He W., Huang H., An L., Wang D., Zhang F.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 4
Mountain environmental stresses result in increased formation of hydrogen peroxide (H₂O₂) and accumulation of malondialdehyde (MDA) in leaves of Polygonum viviparum. The activities of several antioxidative system enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), glutathione reductase (GR, EC 1.6.4.2), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and the contents of several non-enzymatic antioxidants such as reduced form of ascorbate (ASC), dehydroascorbate (DHA), reduced glutathione (GSH), and oxidized glutathione (GSSG) were investigated in leaves of P. viviparum, which were collected from three altitudes (2,200, 3,200, and 3,900 m) of Tianshan Mountain in China. The activities of these four antioxidative enzymes were accompanied by increases of H₂O₂ levels from 2,200 to 3,200 m. However, the activities of CAT and POD were decreased, whereas the activities of SOD and GR continually increased at 3,900 m. Analyses of isoforms of SOD, CAT, POD, and GR showed that the leaves of P. viviparum exposed different altitude conditions are capable of differentially altering the intensity. Additionally, two new isoforms of SOD were detected at 3900 m. A continual increase in the ASC, ASC to DHA ratio, GSH and GSH/ [GSH + GSSG] ratio, and the activity of DHAR were observed in leaves of P. viviparum with the elevation of altitude. These results suggest that the higher contents of ASC, GSH as well as an increase in reduced redox state may be essential to antioxidation processes in the leaves of P. viviparum, whereas antioxidant enzymes system is a cofactor in the processes.
8

Hydrogen peroxide is involved in the regulation of rice (Oryza sativa L.) tolerance to salt stress

76%
Wang X., Hou C., Liu J., He W., Nan W., Gong H., Bi Y.
Acta Physiologiae Plantarum
|
2013
|
tom 35
|
nr 03
In the present study, we investigated the salt tolerance mechanism of two rice cultivars (Zhenghan-2 and Yujing-6), which show different tolerance to drought and disease. NaCl induced higher extent of lipid peroxide and ion leakage in Yujing-6 roots than those in Zhenghan-2 roots. H2O2 accumulation in Zhenghan-2 roots was lower than that in Yujing-6 roots under salt stress. Comparatively, NaCl treatment did not increase O2 - contents in both rice roots, however, O2 - level in Yujing-6 roots was higher than that in Zhenghan-2 roots under both control and salt stress conditions. Ascorbate peroxidases (APX) activity increased more significantly in Zhenghan-2 roots than that in Yujing-6 roots. The activity of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glucose- 6-phosphate dehydrogenase (G6PDH) was similarly enhanced in both rice roots under salt stress; however, they showed higher levels in Zhenghan-2 roots than in Yujing-6 roots. Exogenous H2O2 could enhance APX, CAT, POD, SOD and G6PDH activities in a concentration-dependent manner in both rice roots. Diphenylene iodonium (DPI), a plasma membrane (PM) NADPH oxidase inhibitor, which counteracted the NaCl-induced H2O2 accumulation, markedly decreased the activity of above enzymes. Moreover, ion leakage increased dramatically in Zhenghan-2 roots and reached to the similar level of Yujing-6 roots under NaCl+DPI treatment. Taken together, H2O2, which is mainly generated from PM NADPH oxidase, is involved in Zhenghan-2 rice tolerance to salt stress by enhancing the cellular antioxidant level.
9

Pollution assessment of heavy metals in soils and plants around a molybdenum mine in Central China

76%
Han Z., Wan D., Tian H., He W., Wang Z., Liu Q.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 1
Although environmental problems caused by metal mining have become increasingly prominent, the pollution by associated heavy metals is easily neglected. In general, molybdenum mines are lowgrade and hence the high level of associated heavy metals easily causes pollution in the surrounding areas. Here we investigated the total concentrations and forms of Mo and associated Cu, Cd, Pb, and Zn in soils under different land-use types (barren, wheat, rape, and apple-seedling fields) and different plants (cultivated crops and wild wormwood) around an abandoned molybdenum tailings site. The results showed that the average total concentrations of Cu and Zn in farmland bulk soils around the site exceeded the level II standard of the National Environmental Quality Standard for Soils in China, the average Cd and Pb concentrations exceeded the level III standard, and the average Mo concentration exceeds the soil background value in Shaanxi Province. The percentages of available heavy metals in wormwood and seedling rhizosphere soils were significantly higher than those in crop rhizosphere soils. Heavy metals mainly accumulated in the roots of plants tested in this study. The Cu, Cd, and Pb concentrations in wormwood exceeded the limits of these metals in general plants. The Cd and Pb pollution indices of corn at the side of the barren land were 3.12 and 2.48, respectively, and the Pb pollution index of rape was 3.42, according to the standard limit of pollutants in food for China. On the basis of the level III standard, the pollution assessment of soils revealed serious pollution of the barren land and wheat fields, and moderate pollution of the rape and seedling fields. This study indicates that the heavy metals associated with the molybdenum mine have polluted the surrounding soils and plants, of which pollution of the barren land is the most serious.
10

A study of the K drought monitoring model

76%
Wang J., Wang S., Li Y., He W., Liu X., Ren Y.
Polish Journal of Environmental Studies
|
2018
|
tom 27
|
nr 1
This study established a K drought monitoring model to determinate the start, duration, and strength of drought. Based on 586 meteorological stations’ conventional observation data in China from 1961 to 2015, we calculated the elements and parameters needed to structure the model. Because soil has a memory of its antecedent moisture change, the drought intensity of a day is determined by the moisture content of the day and earlier days. Furthermore, the change of moisture content depends not only on precipitation but also on the temperature associated with evaporation. In order to consider the impact of previous precipitation and evaporation on the present drought, we made a cumulative treatment of previous precipitation and reference evapotranspiration. However, the influence degree of the antecedent precipitation and reference evapotranspiration on soil moisture is weakened closer to the present day. This means that the contribution of the precipitation and reference evapotranspiration in earlier days to present soil moisture decays over time. After comparison between the exponential decay form and the linear decay form of the previous precipitation and reference evapotranspiration, the scheme of linear decay form is selected. Then, a K drought monitoring model was established to consider the antecedent precipitation and reference evapotranspiration accumulation and their decay influence. The proposed K drought monitoring model can be used to evaluate the timing of drought onset, evolution process, and severity.
11

The time course of NO involved in ABA pathway to improve drought tolerance in Oxytropis ochrocephala Bunge

76%
Zhuang H., He W., Chen X., Wang L., Ji L., Guo B., Wei Y.
Acta Physiologiae Plantarum
|
2015
|
tom 37
|
nr 07
Oxytropis ochrocephala Bunge is a poisonous legume plant which exhibits drought acclimation behavior and spreads rapidly under adverse environment. This study demonstrates that the stress signals including NO (nitric oxide), ABA (abscisic acid), and H2O2 (Hydrogen peroxide) are involved in roots of O. ochrocephala seedlings when exposed to drought stress simulated by PEG-6000 solution. The relationship among these signals was investigated by using exogenous and endogenous modulators. The results indicate that a time course of NO is accumulated in roots of O. ochrocephala in response to drought stress, which is generated enzymatically by nitrate reductase (NR) activity. The low level of NO acts as a downstream signaling of ABA and is involved with H2O2 signaling cascade. There is a regulatory mechanism of controlling NO concentration and maintaining the equilibrium state between ROS (reactive oxygen species) and NO, which modulates the root cell vitality, and osmotic adjustment thus improves root growth and developmental processes under drought stress.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.