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Allometric response of perennial Pennisetum centrasiaticum Tzvel to nutrient and water limitation in the Horqin Sand Land of China 被引量:4
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作者 Wei MAO TongHui ZHANG +2 位作者 yulin li XueYong ZHAO YingXin HUANG 《Journal of Arid Land》 SCIE 2012年第2期161-170,共10页
Optimal partitioning theory (OPT) suggests that plants should allocate relatively more biomass to the organs that acquire the most limited resources. The assumption of this theory is that plants trade off the biomas... Optimal partitioning theory (OPT) suggests that plants should allocate relatively more biomass to the organs that acquire the most limited resources. The assumption of this theory is that plants trade off the biomass allocation between leaves, stems and roots. However, variations in biomass allocation among plant parts can also occur as a plant grows in size. As an alternative approach, allometric biomass partitioning theory (APT) asserts that plants should trade off their biomass between roots, stems and leaves. This approach can minimize bias when comparing biomass allocation patterns by accounting for plant size in the analysis. We analyzed the biomass allo- cation strategy of perennial Pennisetum centrasiaticum Tzvel in the Horqin Sand Land of northern China by treating samples with different availabilities of soil nutrients and water, adding snow in winter and water in summer. We hypothesized that P. centrasiaticum alters its pattern of biomass allocation strategy in response to different levels of soil water content and soil nitrogen content. We used standardized major axis (SMA) to analyze the allometric rela- tionship (slope) and intercept between biomass traits (root, stem, leaf and total biomass) of nitrogen/water treat- ments. Taking plant size into consideration, no allometric relationships between different organs were significantly affected by differing soil water and soil nitrogen levels, while the biomass allocation strategy of P. centrasiaticum was affected by soil water levels, but not by soil nitrogen levels. The plasticity of roots, leaves and root/shoot ratios was 'true' in response to fluctuations in soil water content, but the plasticity of stems was consistent for trade-offs between the effects of water and plant size. Plants allocated relatively more biomass to roots and less to leaves when snow was added in winter. A similar trend was observed when water was added in summer. The plasticity of roots, stems and leaves was a function of plant size, and remained unchanged in response to different soil nitrogen levels. 展开更多
关键词 optimal partitioning allometric biomass partitioning limited resources biomass allocation allometric relationships
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Photosynthesis of Digitaria ciliaris during repeated soil drought and rewatering 被引量:2
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作者 YaYong Luo XueYong Zhao +3 位作者 JingHui Zhang yulin li XiaoAn Zuo DianChao Sun 《Research in Cold and Arid Regions》 CSCD 2015年第1期81-87,共7页
The ability of psammophyte photosynthesis to withstand and recover from severe droughts is crucial for vegetation sta- bility in semi-arid sandy lands. The responses of gas exchange and chlorophyll fluorescence of an ... The ability of psammophyte photosynthesis to withstand and recover from severe droughts is crucial for vegetation sta- bility in semi-arid sandy lands. The responses of gas exchange and chlorophyll fluorescence of an annual grass, Digitaria ciliaris, were measured through three soil drought and rewatering cycles. Results showed that the net photosynthesis rate (P,) decreased by 92%, 95%, and 63% at end of the three drought periods, respectively, water use efficiency (WUE) decreased by 67%, 54%, and 48%, while the constant intercellular CO2 concentration (Ci) increased by 1.08, 0.88, and 0.45 times. During those three cycles, the trapping probability with no dark adaptation (Fv'/Fm') decreased by 55%, 51%, and 9%, the electron transport per cross section (ET0'/CS0') decreased by 63%0, 42%, and 18%, and the dissipation per cross section (DI0'/CS0') increased by 97%, 96%, and 21%. These results indicated that D. ciliaris was subjected to photoinhi- bition and some non-stomatal limitation of photosynthesis under drought. However, after four days of rewatering, its photosynthetic characteristics were restored to control values. This capability to recover from drought may contribute to making the plant's use of water as efficient as possible. Furthermore, the photosynthesis decreased more slowly in the subsequent drought cycles than in the first cycle, allowing D. ciliaris to enhance its future drought tolerance after drought hardening. Thus, it acclimatizes itself to repeated soil drought. 展开更多
关键词 chlorophyll fluorescence gas exchange repeated soil drought and rewatering JIP-TEST
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Comparison of sampling schemes for spatial predictionof soil organic carbon in Northern China 被引量:1
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作者 XuYang Wang YuQiang li +3 位作者 yulin li YinPing Chen Jie lian WenJie Cao 《Research in Cold and Arid Regions》 CSCD 2020年第4期200-216,共17页
Determining an optimal sample size is a key step in designing field surveys,and is particularly important for detecting the spatial pattern of highly variable properties such as soil organic carbon(SOC).Based on 550 s... Determining an optimal sample size is a key step in designing field surveys,and is particularly important for detecting the spatial pattern of highly variable properties such as soil organic carbon(SOC).Based on 550 soil sampling points in the nearsurface layer(0 to 20 cm)in a representative region of northern China's agro-pastoral ecotone,we studied effects of four interpolation methods such as ordinary kriging(OK),universal kriging(UK),inverse distance weighting(IDW)and radial basis function(RBF)and random subsampling(50,100,200,300,400,and 500)on the prediction accuracy of SOC estimation.When the Shannon's Diversity Index(SHDI)and Shannon's Evenness Index(SHEI)was 2.01 and 0.67,the OK method appeared to be a superior method,which had the smallest root mean square error(RMSE)and the mean error(ME)nearest to zero.On the contrary,the UK method performed poorly for the interpolation of SOC in the present study.The sample size of 200 had the most accurate prediction;50 sampling points produced the worst prediction accuracy.Thus,we used 200 samples to estimate the study area's soil organic carbon density(SOCD)by the OK method.The total SOC storage to a depth of 20 cm in the study area was 117.94 Mt,and its mean SOCD was 2.40 kg/m2.The SOCD kg/(C⋅m2)of different land use types were in the following order:woodland(3.29)>grassland(2.35)>cropland(2.19)>sandy land(1.55). 展开更多
关键词 soil organic carbon sample size GEOSTATISTICS KRIGING prediction accuracy
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Effects of grazing and climate change on sandy grassland ecosystems in Inner Mongolia 被引量:1
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作者 Halin Zhao Toshiya Okuro +2 位作者 Ruilian Zhou yulin li XiaoAn Zuo 《Research in Cold and Arid Regions》 2011年第3期223-232,共10页
To understand the effects of grazing activities and climate change on sandy grassland ecosystems in northem China, a livestock field grazing and enclosure experiment was conducted from 1992 to 2006 in Horqin Sand Land... To understand the effects of grazing activities and climate change on sandy grassland ecosystems in northem China, a livestock field grazing and enclosure experiment was conducted from 1992 to 2006 in Horqin Sand Land, Inner Mongolia. The results showed that sustained heavy grazing resulted in serious degradation of the vegetation; moderate grazing can maintain vegetation stabilization; and light grazing can promote rapid restoration of degraded vegetation. The livestock productivity was the highest in the moderate grazing grassland, and sustained heavy grazing resulted in rapid decrease of the livestock productivity. Heavy grazing can cause a retrogressive succession of grassland vegetation, whereas moderate and light grazing may promote progressive succession of plant species. The effects of changing climate on succession processes were not significant in the short term; a warm-humid climate is favorable to restoration of degraded vegetation, whereas a sustained warm-drought climate may result in degradation of grassland vegetation. Heavy livestock grazing should be stopped for the sustainable use of grassland; the proper grazing intensity for sandy grassland is two to three sheep or sheep equivalents per hectare in Inner Mongolia. 展开更多
关键词 grazing intensity climate change sandy grassland ecosystem dynamics Inner Mongolia
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X-irradiation for inhibiting glial scar formation in injured spinal cord
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作者 Guangzhi Ning Renhui Chen +4 位作者 yulin li Qiang Wu Qiuli Wu Yan li Shiqing Feng 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第17期1582-1589,共8页
X-irradiation has a beneficial effect in treating spinal cord injury. We supposed that X-irradiation could improve the microenvironment at the site of a spinal cord injury and inhibit glial scar formation. Thus, this ... X-irradiation has a beneficial effect in treating spinal cord injury. We supposed that X-irradiation could improve the microenvironment at the site of a spinal cord injury and inhibit glial scar formation. Thus, this study was designed to observe the effects of 8 Gy X-irradiation on the injury site at 6 hours and 2, 4, 7, and 14 days post injury, in terms of improvement in the microenvironment and hind limb motor function. Immunohistochemistry showed that the expression of macrophage marker ED-1 and the area with glial scar formation were reduced. In addition, the Basso, Beattie and Bresnahan score was higher at 7 days post injury relative to the other time points post injury. Results indicated that X-irradiation at a dose of 8 Gy can inhibit glial scar formation and alleviate the inflammatory reaction, thereby repairing spinal cord injury. X-irradiation at 7 days post spinal cord injury may be the best time window. 展开更多
关键词 neural regeneration spinal cord glial scar X-IRRADIATION functional recovery ASTROCYTES grants-supported paper NEUROREGENERATION
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Climate and salinity drive soil bacterial richness and diversity in sandy grasslands in China
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作者 ChengChen Pan XiaoYa Yu +2 位作者 Qi Feng yulin li ShiLong Ren 《Research in Cold and Arid Regions》 CSCD 2022年第3期182-195,共14页
Bacteria constitute a large proportion of the biodiversity in soils and control many important processes in terrestrial ecosystems.However,our understanding of the interactions between soil bacteria and environmental ... Bacteria constitute a large proportion of the biodiversity in soils and control many important processes in terrestrial ecosystems.However,our understanding of the interactions between soil bacteria and environmental factors remains limited,especially in sensitive and fragile ecosystems.In this study,geographic patterns of bacterial diversity across four sandy grasslands along a 1,600 km north-south transect in northern China were characterized by high-throughput 16S rRNA gene sequencing.Then,we analyzed the driving factors behind the patterns in bacterial diversity.The results show that of the 21 phyla detected,the most abundant were Proteobacteria,Actinobacteria,Acidobacteria and Fir‐micutes(average relative abundance>5%).Soil bacterial operational taxonomic unit(OTU)numbers(richness)and Faith's phylogenetic diversity(diversity)were highest in the Otindag Sandy Land and lowest in the Mu Us Sandy Land.Soil electrical conductivity(EC)was the most influential factor driving bacterial richness and diversity.The bacterial communities differed significantly among the four sandy grasslands,and the bacterial community structure was signifi‐cantly affected by environmental factors and geographic distance.Of the environmental variables examined,climatic factors(mean annual temperature and precipitation)and edaphic properties(pH and EC)explained the highest propor‐tion of the variation in bacterial community structure.Biotic factors such as plant species richness and aboveground bio‐mass exhibited weak but significant associations with bacterial richness and diversity.Our findings revealed the impor‐tant role of climate and salinity factors in controlling bacterial richness and diversity;understanding these roles is critical for predicting the impacts of climate change and promoting sustainable management strategies for ecosystem services in these sandy lands. 展开更多
关键词 sandy land soil bacterial diversity BIOGEOGRAPHY climate change SALINITY
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Nitrogen Content Inversion of Corn Leaf Data Based on Deep Neural Network Model
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作者 yulin li Mengmeng Zhang +2 位作者 Maofang Gao Xiaoming Xie Wei li 《Journal of Beijing Institute of Technology》 EI CAS 2023年第5期619-630,共12页
To obtain excellent regression results under the condition of small sample hyperspectral data,a deep neural network with simulated annealing(SA-DNN)is proposed.According to the characteristics of data,the attention me... To obtain excellent regression results under the condition of small sample hyperspectral data,a deep neural network with simulated annealing(SA-DNN)is proposed.According to the characteristics of data,the attention mechanism was applied to make the network pay more attention to effective features,thereby improving the operating efficiency.By introducing an improved activation function,the data correlation was reduced based on increasing the operation rate,and the problem of over-fitting was alleviated.By introducing simulated annealing,the network chose the optimal learning rate by itself,which avoided falling into the local optimum to the greatest extent.To evaluate the performance of the SA-DNN,the coefficient of determination(R^(2)),root mean square error(RMSE),and other metrics were used to evaluate the model.The results show that the performance of the SA-DNN is significantly better than other traditional methods. 展开更多
关键词 precision agriculture deep neural network nitrogen content detection regression model
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Assessment on Fault Diagnosis and State Evaluation of New Power Grid:AReview
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作者 Bo Yang yulin li +3 位作者 Yaxing Ren Yixuan Chen Xiaoshun Zhang Jingbo Wang 《Energy Engineering》 EI 2023年第6期1287-1293,共7页
1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,t... 1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,the proposed strategic targets of“carbon neutralization and carbon peaking”must be implemented and insisted[1].The core feature of the new power system is that renewable energy plays a leading role and becomes the main source of energy supply,meanwhile,the goal of green energy utilization has also been put forward on the agenda.Green energy utilization includes two aspects,one is the exploitation and promotion of various green energy technologies,and the other is the digitalization of energy management.Under this trend,stochastic and fluctuating energy sources such as wind power and photovoltaic power replace deterministic controllable power sources such as thermal power,bringing challenges to power grid regulation and dispatching,as well as flexible operation.The large-scale integration of renewable energy and increasingly high proportion of power electronic equipment tend to bring about fundamental changes in the operation characteristics,safety control,and production mode of the power system. 展开更多
关键词 Carbon neutrality and carbon peak goals renewable energy fault diagnosis state evaluation new power grid
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F127辅助制备介孔Fe/TiO_2催化剂用于中温NH_3选择性催化还原反应(英文) 被引量:2
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作者 李昱琳 韩小金 +5 位作者 侯亚芹 郭耀萍 刘勇进 向宁 崔燕 黄张根 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第11期1831-1841,共11页
NOx是大气污染物的重要组成部分,能够造成酸雨、光化学烟雾和臭氧层破坏等一系列环境问题,严重危害人类健康.选择性催化还原(SCR)是控制NOx排放的主要技术,当前工业上普遍采用的是钒钛催化剂,然而该催化剂活性温度窗口较窄(300-400 ℃),... NOx是大气污染物的重要组成部分,能够造成酸雨、光化学烟雾和臭氧层破坏等一系列环境问题,严重危害人类健康.选择性催化还原(SCR)是控制NOx排放的主要技术,当前工业上普遍采用的是钒钛催化剂,然而该催化剂活性温度窗口较窄(300-400 ℃),N_2选择性较低,而且钒物种本身有毒.因此开发新型SCR催化剂成为研究热点.Fe/TiO_2催化剂具有稳定的化学性质,环境污染少且价格低廉,近年来受到广泛关注.为了提高Fe/TiO_2催化活性,人们采用了各种不同的制备方法.本文以F127作为结构导向剂,结合溶胶-凝胶法原位合成了具有介孔结构、工作温度在150-300 ℃的Fe/TiO_2脱硝催化剂,并与普通浸渍法和共沉淀法制备的催化剂进行了对比.利用N_2吸附脱附、紫外-可见光谱、X射线电子能谱、NH_3程序升温脱附和原位红外光谱等技术研究了制备方法对Fe/TiO_2催化剂物理结构及脱硝性能的影响.结果表明,相较于浸渍法和共沉淀法,模板法制备的催化剂具有较高的脱硝效率和抗H_2O和SO_2性能.作为结构导向剂,F127能够诱导催化剂形成均匀的介孔结构,有利于提高催化剂比表面积,促进反应物分子的扩散和转移,从而提高催化剂脱硝效率.进一步研究发现,模板法能够明显促进活性组分Fe物种的分散和NH_3吸附,载体与活性组分具有较强的相互作用,因而有利于催化剂产生较多的活性位.结合XPS结果,较多的活性位点有利于表面吸附氧(O_α)在催化剂表面的吸附.Oα有利于NO到NO_2的转化,从而促进快速SCR反应:NO+NO_2+2NH_3→2N_2+3H_2O.通过原位红外机理分析证明,吸附在模板法制备的催化剂表面的NO物种具有较强的稳定性,当温度超过200 ℃时,仍然保持一定的吸附强度;吸附NH_3红外结果表明,Lewis酸性位比Br?nsted酸性位具有更强的稳定性,当温度超过150℃仍然具有较强的Lewis酸吸附.催化剂表面稳定的NO物种和Lewis酸位上强的NH_3吸附是催化剂催化活性增加的重要原因. 展开更多
关键词 Fe/TiO2 介孔结构 相互作用 中温氨选择催化还原
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N and P resorption in a pioneer shrub(Artemisia halodendron) inhabiting severely desertified lands of Northern China 被引量:11
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作者 yulin li Chen JING +3 位作者 Wei MAO Duo CUI XinYuan WANG XueYong ZHAO 《Journal of Arid Land》 SCIE CSCD 2014年第2期174-185,共12页
Nutrient resorption is an important conservation mechanism for plants to overcome nutrient limitation in the less fertile area of desertifled land. In the semi-arid Horqin Sandy Land of Northern China, the shrub Artem... Nutrient resorption is an important conservation mechanism for plants to overcome nutrient limitation in the less fertile area of desertifled land. In the semi-arid Horqin Sandy Land of Northern China, the shrub Artemisia ha/odendron usually colonizes into the bare ground of severely desertified land as a pioneer species. It is, therefore, expected that A. ha/odendron will be less dependent on current nutrient uptake through efficient and proficient re- sorption of nutrients. In this study, we found that averaged nitrogen (N) and phosphorus (P) concentrations in se- nesced leaves significantly varied from 12.3 and 1.2 mg/g in the shifting sand dune to 15.9 and 1.9 mg/g in the fixed sand dune, respectively, suggesting that foliar N and P resorption of A. ha/odendron were more proficient in the shifting sand dune. In particular, positive relationships between nutrient concentrations in senesced leaves and soil nutrient availability indicate that A. ha/odendron in infertile habitats is more likely to manage with a low level of nu- trients in senesced leaves, giving this species an advantage in infertile soil. Moreover, foliar N- and P-resorption efficiencies and proficiencies showed limited inter-annual variability although annual precipitation varied greatly among 2007-2009. However, N and P resorption of A. ha/oc/endron were not more efficient and proficient than those previously reported for other shrubs, indicating that the pioneer shrub in sand dune environments does not rely more heavily than other plants on the process of resorption to conserve nutrients. Incomplete resorption of nutrients in A. halodendron suggests that senesced-leaf fall would return litter with high quality to the soil, and thereby would indirectly improve soil nutrient availability. The restoration of desertified land, therefore, may be ac- celerated after A. halodendron pioneers into shifting sand dunes. 展开更多
关键词 foliar nutrient concentration nutrient-resorption efficiency nutrient-resorption proficiency senesced vs. green leaves DESERTIFICATION soil nutrient availability
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Comparison of soil physico-chemical properties under different land-use and cover types in northeastern China's Horqin Sandy Land 被引量:4
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作者 YuQiang li JianPeng Zhang +4 位作者 XueYong Zhao TongHui Zhang yulin li XinPing liu YinPing Chen 《Research in Cold and Arid Regions》 CSCD 2016年第6期495-506,共12页
The Horqin Sandy Land of northeastern China was originally a grassland with plenty of water and lush vegetation dominated by palatable grass species along with sparsely scattered woody species. However, it has experie... The Horqin Sandy Land of northeastern China was originally a grassland with plenty of water and lush vegetation dominated by palatable grass species along with sparsely scattered woody species. However, it has experienced severe desertification in recent decades due to its fragile ecology together with inappropriate human activities. Currently, the landscape of the Horqin Sandy Land is dominated by irrigated croplands and sand dunes with different degrees of vegetation cover, as the region has become the most important part of the semiarid agro-pastoral ecotone of northern China. In this study, we compared soil physical and chemical properties under different land-use and cover types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes). We found that soil particle size distribution; organic C, total N, and total mineral element, microelement, and available microelement and nutrient contents; pH; CEC; and bulk density differed significantly among the land-use and cover types. In general, soil quality was highest in the cropland, intermediate in the sandy grassland, and lowest in the dunes. The most important soil quality attribute, soil organic carbon (SOC) storage, decreased in the fol-lowing order: irrigated cropland (5,699 g/m^2) 〉 sandy grassland (3,390 g/m^2) 〉 rainfed cropland (2,411 g/m^2) 〉 fixed dunes (821 g/m^2) 〉 mobile dunes (463 g/m^2). SOC was significantly positively correlated with a large proportion of the other soil physico-chemical parameters. Our results suggest that the key issue in restoration of the degraded soils will be to increase SOC storage, which would also create a high potential for sequestering soil C in desertified areas of the Horqin Sandy Land. 展开更多
关键词 land use land cover soil properties DESERTIFICATION Horqin Sandy Land
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Increasing rainfed wheat yield by optimizing agronomic practices to consume more subsoil water in the Loess Plateau 被引量:3
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作者 Wenjia Yang Weijian liu +3 位作者 yulin li Shiwen Wang lina Yin Xiping Deng 《The Crop Journal》 SCIE CSCD 2021年第6期1418-1427,共10页
Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in ... Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in this region, the effects of different agronomic practices, including adjusting planting pattern(NR, narrow row spacing), increasing seeding rate(high seeding rate, HS), decreasing basal nitrogen rate and increasing top-dressed nitrogen rate(DBN), and replacing an old cultivar with a new cultivar(NC) on wheat yield were investigated for two consecutive years. The results showed that the current grain yield of rainfed winter wheat in the Loess Plateau could be increased to 5879–7093 kg ha^(-1) by HS, DBN and NC practices relative to the practice of high-yielding farmers(PF). The increased yield due to HS, DBN and NC was attributed to the higher number of spikes ha^(-1), 1000-grain weight, and kernels spike^(-1). Before the flowering stage, HS increased soil water consumption(SWC) in 1–3 m subsoil due to the higher plant population compared with that of PF, whereas DBN decreased SWC in the 0–2 m soil layer compared with that of PF. After the flowering stage, HS, DBN, and NC increased SWC by 8–16 mm in 2–3 m subsoil compared to PF. The water use efficiency(WUE) was increased under DBN and NC in comparison with PF.However, the WUE did not increase under HS as it had the highest evapotranspiration among the five treatments. Increasing the use of subsoil water during the late growth stage by optimizing agronomic practices or applying new cultivars with expansive roots should be the primary approach to increase rainfed winter wheat yield in this region. 展开更多
关键词 Winter wheat Agronomic practices Soil water consumption Grain yield Loess Plateau
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Accumulation of soil organic carbon during natural restoration of desertified grassland in China's Horqin Sandy Land 被引量:22
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作者 YuQiang li XueYong ZHAO +5 位作者 FengXia ZHANG Tala AWADA ShaoKun WANG Halin ZHAO TongHui ZHANG yulin li 《Journal of Arid Land》 SCIE CSCD 2015年第3期328-340,共13页
China's Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon(C) losses from the plant-soil system.Natural restoration through grazing exclusion is a ... China's Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon(C) losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon(LFOC) storage increased by 221 g C/m2(84%) and the total soil organic carbon(SOC) storage increased by 435 g C/m2(55%).The light fraction dry matter content represented a small proportion of the total soil mass(ranging from 0.74% in 2005 to 1.39% in 2013),but the proportion of total SOC storage accounted for by LFOC was remarkable(ranging from 33% to 40%).The C sequestration averaged 28 g C/(m2·a) for LFOC and 54 g C/(m2·a) for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt+clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land. 展开更多
关键词 carbon storage carbon sequestration soil light fraction restoration grazing exclusion
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A mechanism for the origin and development of the large-scale dunefield on the right flank of the lower reach of Laoha River,Northeast China 被引量:1
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作者 Guang Han GuiFang Zhang +5 位作者 li You liang Zhou lin Yang XueYong Zhao yulin li TongHui Zhang 《Research in Cold and Arid Regions》 CSCD 2015年第1期29-39,共11页
By viewing satellite imagery, a striking large-scale dunefield can be clearly perceived, with a size of nearly 63 km long and 11 km wide, and trending NE-SW, on the right flank of the lower Laoha River, Northeast Chin... By viewing satellite imagery, a striking large-scale dunefield can be clearly perceived, with a size of nearly 63 km long and 11 km wide, and trending NE-SW, on the right flank of the lower Laoha River, Northeast China. By means of remote sensing imagery analysis and field observation as well as a comparison with a small-scale dunefield on the right flank of the lower Xiangshui River, analogous to the case of the lower Laoha River, this paper presents a new mechanism for its origin and development. The results show that: (1) the large-scale dunefield bears a tile-style framework overwhelmingly composed of transverse barchanoid ridges perpendicular to the predominant winds, and inlaid diverse blowouts. (2) The small-scale dunefield, referred to as a primary structural unit of the large one, is typical of an incipient dunefield, following the same rules of evolution as the larger. (3) A succession of barchanoid ridge chains can steadily migrate downwind in much the same manner as surface wave propagation in air or water stimulated by an incised valley, and ultimately tend to bear roughly the same wavelength and amplitude under stable climate and hydrologic regimes. (4) The first ridge chain acquires its sand source substantially from the downwind escarpments exposing the loose Quaternary sandy sediments to the air, while the ensuing ridges derive their sands dominantly from in situ deflation of the underlain Quaternary loose sandy sediments in blowouts, partly from the upwind ridges through northern elongated horns. Theoretically, the sands from riparian escarpments can be transported by wind to the downwind distal end of a dunefield after sufficient long du- ration. (5) The lower Laohahe region experienced probably three significant climatic changes in the past, corresponding to the three active dune belts, suggesting that once a large-scale dunefield occurs, it is nearly impossible to be completely stabilized, at least in its central portions. At present, seasonal shrinkage and stagnation of the lower Laoha River, wide-spread farming and afforestation in the valley, and establishing windbreaks downwind of the valley as well as surrounding the dunefield, appear to have significantly modified local flow fields and sand sources, engendering significant degradation of the dunefield. 展开更多
关键词 lower Laoha River large-scale dunefield wavy barchanoid ridges topographic perturbation blowouts
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Injectable nanofiber-reinforced bone cement with controlled biodegradability for minimally-invasive bone regeneration 被引量:3
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作者 Peihao Cai Shunyi Lu +11 位作者 Jieqin Yu Lan Xiao Jiayi Wang Haifeng liang Lei Huang Guanjie Han Mengxuan Bian Shihao Zhang Jian Zhang Changsheng liu libo Jiang yulin li 《Bioactive Materials》 SCIE CSCD 2023年第3期267-283,共17页
Injectable materials show their special merits in regeneration of damaged/degenerated bones in minimally-invasive approach.Injectable calcium phosphate bone cement(CPC)has attracted broad attention for its bioactivity... Injectable materials show their special merits in regeneration of damaged/degenerated bones in minimally-invasive approach.Injectable calcium phosphate bone cement(CPC)has attracted broad attention for its bioactivity,as compared to non-degradable polymethyl methacrylate cement.However,its brittleness,poor anti-washout property and uncontrollable biodegradability are the main challenges to limit its further clinical application mainly because of its stone-like dense structure and fragile inorganic-salt weakness.Herein,we developed a kind of injectable CPC bone cement with porous structure and improved robustness by incorporating poly(lactide-co-glycolic acid)(PLGA)nanofiber into CPC,with carboxymethyl cellulose(CMC)to offer good injectability as well as anti-wash-out capacity.Furthermore,the introduction of PLGA and CMC also enabled a formation of initial porous structure in the cements,where PLGA nanofiber endowed the cement with a dynamically controllable biodegradability which provided room for cell movement and bone ingrowth.Inter-estingly,the reinforced biodegradable cement afforded a sustainable provision of Ca^(2+)bioactive components,together with its porous structure,to improve synergistically new bone formation and osteo-integration in vivo by using a rat model of femur condyle defect.Further study on regenerative mechanisms indicated that the good minimally-invasive bone regeneration may come from the synergistic enhanced osteogenic effect of calcium ion enrichment and the improved revascularization capacity contributed from the porosity as well as the lactic acid released from PLGA nanofiber.These results indicate the injectable bone cement with high strength,anti-washout property and controllable biodegradability is a promising candidate for bone regeneration in a minimally-invasive approach. 展开更多
关键词 Injectable calcium phosphate cement Biodegradable PLGA nanofiber Angiogenesis OSSEOINTEGRATION Minimally-invasive bone regeneration
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Relationship between the haplotype distribution of Artemisia halodendron(Asteraceae) and hydrothermal regions in Horqin Sandy Land, northern China
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作者 WenDa Huang XueYong Zhao +2 位作者 yulin li YuQiang li YaYong Luo 《Research in Cold and Arid Regions》 CSCD 2018年第2期151-158,共8页
The genetic diversity of Artemisia halodendron(Asteraceae), a constructive and dominant species in Horqin Sandy Land,was investigated to examine the genetic relationships with different hydrothermal regions in Horqin ... The genetic diversity of Artemisia halodendron(Asteraceae), a constructive and dominant species in Horqin Sandy Land,was investigated to examine the genetic relationships with different hydrothermal regions in Horqin Sandy Land. We sequenced chloroplast DNA(cp DNA) fragments(trn L–F) of 243 plants from 10 populations across the Horqin Sandy Land.The analyses of cp DNA variation identified seven haplotypes. A low level of haplotype diversity(H_d=0.706) and nucleotide diversity(π=0.0013) was detected. Haplotypes clustered into two tentative clades. Low genetic differentiation among regions was consistently indicated by hierarchical analyses of molecular variance(AMOVA). Across the sampled populations, the haplotype distributions were differentiated with hydrothermal gradients. 展开更多
关键词 ARTEMISIA halodendron population genetics CHLOROPLAST DNA TRNL-F Horqin SANDY Land
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ISSR analysis of Caragana microphylla(Leguminosae) in different temperature gradients
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作者 WenDa Huang XueYong Zhao +4 位作者 yulin li YuQiang li YaYong Luo Jing Feng Na Su 《Research in Cold and Arid Regions》 CSCD 2015年第1期99-103,共5页
Caragana microphylla is the most dominant and constructive shrub species in the Horqin Sandy Land of northeastern China. We evaluated the level of genetic variation within and among C. microphylla populations sampled ... Caragana microphylla is the most dominant and constructive shrub species in the Horqin Sandy Land of northeastern China. We evaluated the level of genetic variation within and among C. microphylla populations sampled from three different temperature gradients in the Horqin Sandy Land by using inter-simple sequence repeat polymorphism (ISSR) molecular markers. The results show that eight ISSR primers generated 127 bands, of which 123 (96.85%) were polymorphic. At the species level, genetic diversity was relatively high (P = 96.85%, h = 0.3143, I = 0.4790). The highest genetic diversity was observed in the Subp6 population from low temperature regions, whereas the lowest diversity was found in the Subp2 population from high temperature regions. Six populations of C. microphylla clustered into two clades. These results have important implications for restoring and managing the degraded ecosystem in arid and semi-arid areas. 展开更多
关键词 Caragana microphylla temperature gradients ISSR Horqin Sandy Land
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Changes in soil and vegetation on moving sand dunes after exclosure in Horqin Sandy Land, Northern China
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作者 yulin li JianYuan Cui +1 位作者 XueYong Zhao YongZhong Su 《Research in Cold and Arid Regions》 2010年第4期335-344,共10页
关键词 DESERTIFICATION vegetation recovery species diversity soil organic carbon
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Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases 被引量:1
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作者 Yumin Wang Jing Hu +8 位作者 Shuang Wu Joshua S.Fleishman yulin li Yinshi Xu Wailong Zou Jinhua Wang Yukuan Feng Jichao Chen Hongquan Wang 《Signal Transduction and Targeted Therapy》 SCIE CSCD 2024年第1期105-149,共45页
Ferroptosis,a unique modality of cell death with mechanistic and morphological differences from other cell death modes,plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating antic... Ferroptosis,a unique modality of cell death with mechanistic and morphological differences from other cell death modes,plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance.Aberrant epigenetic modifications and posttranslational modifications(PTMs)promote anticancer drug resistance,cancer progression,and metastasis.Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases(NSDs),cardiovascular diseases(CVDs),liver diseases,lung diseases,and kidney diseases.In this review,we first summarize the core molecular mechanisms of ferroptosis.Then,the roles of epigenetic processes,including histone PTMs,DNA methylation,and noncoding RNA regulation and PTMs,such as phosphorylation,ubiquitination,SUMOylation,acetylation,methylation,and ADP-ribosylation,are concisely discussed.The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases,including cancers,NSD,CVDs,liver diseases,lung diseases,and kidney diseases,as well as the application of epigenetic and PTM modulators in the therapy of these diseases,are then discussed in detail.Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases.In addition,these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases. 展开更多
关键词 DISEASES EPIGENETIC OVERCOME
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CHD4-induced up-regulation of ERα activity contributes to breast cancer progression
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作者 Aman Sattout Xiaomin Yu +5 位作者 Zhuo Sun Yanan li yulin li Shujing li Wei Huo Huijian Wu 《Genes & Diseases》 SCIE CSCD 2024年第3期132-135,共4页
The estrogen signaling system is a crucial regulator of metabolicandphysiologicalprocesses.However,abnormal activation of estrogen signaling may play a role in breast cancer initiation and progression.Crucial to this ... The estrogen signaling system is a crucial regulator of metabolicandphysiologicalprocesses.However,abnormal activation of estrogen signaling may play a role in breast cancer initiation and progression.Crucial to this pathway is the interaction between estrogen receptor alpha(ERa)and various co-transcription activators.1 Although numerous studies have investigated ER coregulators,the protein-protein interaction networks of ERa are not fully understood.Recent research has shown that high chromodomain helicase DNA-binding 4(CHD4)expression is linked to poor prognosis in various cancers.2,?In this study,we demonstrated that both CHD4 and ERαcontribute to breast cancer progression while providing evidence of the regulatory processes and functional interplay between these two proteins. 展开更多
关键词 BREAST CANCER ERΑ
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