The concentrations and stoichiometry of soil carbon (c), nitrogen (N), and phosphorus (P) have critical implications for nutrient cycling and ecosystem function. While their high sensitivity to atmospheric N depositio...
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The concentrations and stoichiometry of soil carbon (c), nitrogen (N), and phosphorus (P) have critical implications for nutrient cycling and ecosystem function. While their high sensitivity to atmospheric N deposition is well known, it remains unclear for the soil depth-dependence of such responses to N deposition. Here, we examined the responses of soil c : N : P stoichiometry at three soil depths in the upper humus horizon (0-5, 5-10, and 10-20 cm) of Haplicchernozem (Loamic) across a gradient of urea addition rates (0, 2, 10, 20, and 50 g N m(-2) year(-1)) after five years treatments in a hay-harvest meadow steppe of northern china. We found that the effects of increasing N addition rates on the concentrations and stoichiometry of soil c, N and P did not depend on soil depth, though those parameters varied greatly across different soil layers. Across all soil depths, the concentrations of soil c and N increased with increasing N addition rates, but soil P concentration was not affected by N addition. The higher sensitivity of soil N than soil c to N enrichment resulted in decreasing soil c : N ratio across the N addition gradient, especially for the surface soil layer. Soil N : P ratio showed a positive response to the increases of N addition rates. The unbalanced responses of soil c, N, and P concentrations to N enrichment, as indicated by the decreases of soil c : N ratio and the increases of soil N : P ratio across the N addition gradient, highlighted the role of N enrichment in decoupling soil nutrient cycling in the temperate steppe.
To improve the ablation performance of c/ccomposite at 3000 degrees c, a Zrc-Sic-Si/Sic-Si double-layered coatings (ZSS/SS) was prepared by slurry dipping-carbonization and gaseous silicon infiltration. During ablati...
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To improve the ablation performance of c/ccomposite at 3000 degrees c, a Zrc-Sic-Si/Sic-Si double-layered coatings (ZSS/SS) was prepared by slurry dipping-carbonization and gaseous silicon infiltration. During ablation, a competition between mechanical denudation and oxidation derived thickening occurred. The ZSS/SS coating possessed a superior ablation resistance showing lowest linear ablation rate of 0.53 mu m/s in 90 s with a parabolic rate constant Kp (0.053 mu m/s3). The excellent performance was attributed to good self-sealing of oxidation derived glassy, thus no micro-cracks were observed. However, the Kp became worse to be 0.131 for long-term ablation because of dominant mechanical denudation.
The present work focuses on the assessment and the simulation of the thermomechanical tensile and creep behavior of Poly Ether Ketone Ketone 7002/carbon fibers composites behavior under tensile and creep solicitation ...
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The present work focuses on the assessment and the simulation of the thermomechanical tensile and creep behavior of Poly Ether Ketone Ketone 7002/carbon fibers composites behavior under tensile and creep solicitation between the glass transition temperature and 200 degrees c, via a multiscale approach starting from the behavior of the PEKK 7002 neat *** and creep polymer and composite experimental curves are employed to develop and validate generalized Semi - Analytical Homogenization / Localization Method for the simulation of the thermomechanical tensile and creep behavior of composite laminates. Through the employment of the model, a similarity of behavior between polymer and composites is *** proposed algorithm capabilities of simulating the thermomechanical tensile and creep behavior of composites with different ply orientations and stacking sequences are then presented.
Abnormal activation of the mechanistic target of rapamycin (mTOR) signaling is commonly observed in many cancers and attracts extensive attention as an oncology drug discovery target, which is encouraged by the succes...
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Abnormal activation of the mechanistic target of rapamycin (mTOR) signaling is commonly observed in many cancers and attracts extensive attention as an oncology drug discovery target, which is encouraged by the success of rapamycin and its analogs (rapalogs) in treatment of mTORc1-hyperactive cancers in both pre-clinic models and clinical trials. However, rapamycin and existing rapalogs have typically short lasting partial responses due to drug resistance, thereby triggering our interest to investigate a potential mTORc1 inhibitor that is mechanistically different from rapamycin. Here, we report that hayatine, a derivative from cissampelos, can serve as a potential mTORc1 inhibitor selected from a natural compound library. The unique properties owned by hayatine such as downregulation of mTORc1 activities, induction of mTORc1's translocation to lysosomes followed by autophagy, and suppression on cancer cell growth, strongly emphasize its role as a potential mTORc1 inhibitor. Mechanistically, we found that hayatine disrupts the interaction between mTORc1 complex and its lysosomal adaptor RagA/c by binding to the hydrophobic loop of Ragc, leading to mTORc1 inhibition that holds great promise to overcome rapamycin resistance. Taken together, our data shed light on an innovative strategy using structural interruption-based mTORc1 inhibitors for cancer treatment. (c) 2021 Elsevier Inc. All rights reserved.
We report the application of cuxPd1-xO nanoparticle-reduced graphene oxide nanocomposites as efficient cata-lysts for direct c-H bond activation using alcohols as carbonyl sources. The composition of the cuxPd1-xO nan...
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We report the application of cuxPd1-xO nanoparticle-reduced graphene oxide nanocomposites as efficient cata-lysts for direct c-H bond activation using alcohols as carbonyl sources. The composition of the cuxPd1-xO nanoparticles plays a vital role in determining their catalytic activity because of a composition-dependent synergistic effect. We show that the catalysts can be reused for successive 5 cycles without obviously losing their catalytic activity. Our catalysts offer considerable advantages over previous metallic alloy nanoparticles not only due to their catalytic performance but also for the ease of their synthesis and catalytic robustness.
cunninghamia plays an important role in china's southern forest industry in the face of increasingly arid climate;thus it is urgent to identify and screen drought-tolerant varieties. In this study, 2-year-old seed...
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cunninghamia plays an important role in china's southern forest industry in the face of increasingly arid climate;thus it is urgent to identify and screen drought-tolerant varieties. In this study, 2-year-old seedlings of c. unica and c. lanceolata from four provenances were subjected to water-break tests, and their physiological responses to different drought conditions were observed. The results showed that with the aggravation of drought stress, c. unica had more stable changes in relative water content (RWc), water potential (psi w) and intercellular cO2 concentration (ci) with more cumulative amounts of proline (PRO) than c. lanceolata, and its H2O2 maintained at a lower level, along with antioxidant enzyme activities decreasing later as compared with c. lanceolata. Moreover, comprehensive evaluation showed that c. unica had a higher drought tolerance than c. lanceolata as a whole, which could have been shaped by maintaining psi w and opening stomata in its relative drought conditions. This work provides a theoretical basis for understanding the drought tolerance of c. unica and c. lanceolate individuals, so as to accelerate selective breeding in chinese fir.
Purpose cystic Echinococosis is one of the important parasitic diseases that is considered as a problem economics and health in many parts of the world. Many efforts have been performed for controlling the disease in ...
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Purpose cystic Echinococosis is one of the important parasitic diseases that is considered as a problem economics and health in many parts of the world. Many efforts have been performed for controlling the disease in the world. To reach a reliable vaccine against cystic Echinococosis is one of the important duty of governments. Several antigen of hydatid cyst for vaccine candidate have been evaluated. In this study, P-29 antigen has been used for this purpose. Methods E.g P29 antigen was cloned in Escherichia coli and transfected into the chinese hamster ovary cell for antigen proliferation and used for vaccination in Balb/c mice. The recombinant antigen E.g-29 was shown using Western blot test. Two dilution of DNA vaccine (pcEgP-29) including 50 mu g/100 mu l and 100 mu g/100 mu l were prepared. Twenty four Balb/c male 6-8 week mouse were divided in 4 groups. The groups were included in 2 vaccination groups (pcEg.P29 50 mu g/100 mu l and 100 mu g/100 mu l dilution) as immunized groups and 2 groups of plasmid and PBS as control. The mice were injected intramuscularly 3 times with 2 weeks interval. After 3 weeks from last injection, all groups were challenged intraperitonealy with 2000 protoscolices. After 5 months, the mice were euthanized by ketamine/xylasine injection and number, size, and weight of cysts were recorded. Results Immunization rate was up to 93% in vaccinated group when compared with the control group. conclusion The results of this study showed that rEg.P29 could be considered as an effective vaccine for controlling of E. granulosus prevalence in intermediated host.
作者：
Yang, FangLv, GuanghuiQie, YadongXinjiang Univ
Sch Ecol & Environm Urumqi 830017 Peoples R China Minist Educ
Key Lab Oasis Ecol Urumqi 830017 Peoples R China Minist Educ
Xinjiang Jinghe Observat & Res Stn Temperate Deser Jinghe 833300 Peoples R China Guangxi Univ
Coll Forestry Guangxi Key Lab Forest Ecol & Conservat Nanning 530004 Peoples R China
Growth is restricted by both water and phosphorus (P), and balancing the relationship between non-structural carbohydrates (NScs) and carbon: nitrogen: phosphorus (c:N:P) is essential for Haloxylon ammodendron to adap...
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Growth is restricted by both water and phosphorus (P), and balancing the relationship between non-structural carbohydrates (NScs) and carbon: nitrogen: phosphorus (c:N:P) is essential for Haloxylon ammodendron to adapt to arid habitats. The survival and growth strategies of the dominant species H. ammodendron in a desert ecosystem were examined in order to better serve the restoration of degraded ecosystems and desertification control. Three water and salt gradients (high water and high salinity, medium water and salinity, and low water and low salinity) in the Aibi Lake Reserve were selected. We analyzed the accumulation and distribution of NScs in the assimilation branches and secondary branches of H. ammodendron and the changes in the measurement ratio characteristics of c:N:P, as well as the soil organiccarbon (SOc), total nitrogen (TN), and total phosphorus (TP) content. The results showed that: (1) With the decrease of soil water and salt content, the basal diameter, plant height, crown area, and NSccontent of H. ammodendron significantly decreased. This morphological adjustment in the aboveground part is similar to a "self thinning" behavior, aimed at reducing transpiration area and balancing carbon distribution in the body. The carbon accumulation in the body helps the H. ammodendron to resist the dual stresses of drought and salt. (2) With the decrease of water and salt content, the ccontent of assimilating branches increased significantly, while there was no significant change in secondary branches. However, the N and P content of both branches decreased significantly, and the N: P of both branches was greater than 16, indicating that it was mainly limited by P. (3) The NSc of the two branches was significantly negatively correlated with c, and significantly positively correlated with N and P, and there was a strong positive correlation between the assimilation branches NSc: c: P and NSc: c: P. The synthesis and accumulation of NSc of H. ammodendron wer
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