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1. chinaXiv:201901.00107 [pdf]

Spatial variability of soil water content and related factors across the Hexi Corridor of China

LI Xiangdong; SHAO Ming'an
分类: 生物学 >> 生态学

Soil water content (SWC) is a key factor limiting ecosystem sustainability in arid and semi-arid areas of the Hexi Corridor of China, which is characterized by an ecological environment that is vulnerable to climate change. However, there is a knowledge gap regarding the large-scale spatial distribution of SWC in this region. The specific objectives of this study were to determine the spatial distribution patterns of SWC across the Hexi Corridor and identify the factors responsible for spatial variation of SWC at a regional scale. This study collected and analyzed SWC in the 0–100 cm soil profile from 109 field sampling sites (farmland, grassland and forestland) across the Hexi Corridor in 2017. We selected 17 factors, including land use, topography (latitude, longitude, elevation, slope gradient, and slope aspect), soil properties (soil clay content, soil silt content, soil bulk density, saturated hydraulic conductivity, field capacity, and soil organic carbon content), climate factors (mean annual precipitation, potential evaporation, and aridity index), plant characteristic (vegetation coverage) and planting pattern (irrigation or rain-fed), as possible environmental variables to analyze their effects on SWC. The results showed that SWC was 0.083 (±0.067) g/g in the 0–100 cm soil profile and decreased in the order of farmland, grassland and forestland. The SWC in the upper soil layers (0–20, 20–40 and 40–60 cm) had obvious difference when the mean annual precipitation differed by 200 mm. The SWC decreased from southeast to northwest following the same pattern as precipitation, and had a moderate to strong spatial dependence in a large effective range (75–378 km). The SWC showed a similar distribution and had no significant difference between soil layers in the 0–100 cm soil profile. The principal component analysis showed that the mean annual precipitation, geographical position (longitude and latitude) and soil properties (soil bulk density and soil clay content) were the main factors dominating the variance of environmental variables. A stepwise linear regression equation showed that plant characteristic (vegetation coverage) and soil properties (soil organic carbon content, field capacity and soil clay content) were the optimal factors to predict the variation of SWC. Soil clay content could be better to explain the SWC variation in the deeper soil layers compared with the other factors.

提交时间: 2019-01-17 来自合作期刊:《Journal of Arid Land》 点击量20下载量7 评论 0

2. chinaXiv:201901.00108 [pdf]

Derivation of salt content in salinized soil from hyperspectral reflectance data: A case study at Minqin Oasis, Northwest China

QIAN Tana; Atsushi TSUNEKAWA
分类: 生物学 >> 生态学

Soil salinization is a serious ecological and environmental problem because it adversely affects sustainable development worldwide, especially in arid and semi-arid regions. It is crucial and urgent that advanced technologies are used to efficiently and accurately assess the status of salinization processes. Case studies to determine the relations between particular types of salinization and their spectral reflectances are essential because of the distinctive characteristics of the reflectance spectra of particular salts. During April 2015 we collected surface soil samples (0–10 cm depth) at 64 field sites in the downstream area of Minqin Oasis in Northwest China, an area that is undergoing serious salinization. We developed a linear model for determination of salt content in soil from hyperspectral data as follows. First, we undertook chemical analysis of the soil samples to determine their soluble salt contents. We then measured the reflectance spectra of the soil samples, which we post-processed using a continuum-removed reflectance algorithm to enhance the absorption features and better discriminate subtle differences in spectral features. We applied a normalized difference salinity index to the continuum-removed hyperspectral data to obtain all possible waveband pairs. Correlation of the indices obtained for all of the waveband pairs with the wavebands corresponding to measured soil salinities showed that two wavebands centred at wavelengths of 1358 and 2382 nm had the highest sensitivity to salinity. We then applied the linear regression modelling to the data from half of the soil samples to develop a soil salinity index for the relationships between wavebands and laboratory measured soluble salt content. We used the hyperspectral data from the remaining samples to validate the model. The salt content in soil from Minqin Oasis were well produced by the model. Our results indicate that wavelengths at 1358 and 2382 nm are the optimal wavebands for monitoring the concentrations of chlorine and sulphate compounds, the predominant salts at Minqin Oasis. Our modelling provides a reference for future case studies on the use of hyperspectral data for predictive quantitative estimation of salt content in soils in arid regions. Further research is warranted on the application of this method to remotely sensed hyperspectral data to investigate its potential use for large-scale mapping of the extent and severity of soil salinity.

提交时间: 2019-01-17 来自合作期刊:《Journal of Arid Land》 点击量15下载量6 评论 0

3. chinaXiv:201901.00109 [pdf]

Soil fixation and erosion control by Haloxylon persicum roots in arid lands, Iran

Ehsan ABDI; Hamid R SALEH
分类: 生物学 >> 植物学

Vegetation roots contribute to soil fixation and reinforcement, thus improving soil resistance against erosion. Generally, the amount of soil fixation presented by roots mainly depends on root density and tensile strength. In the present study, we conducted the research in order to further understand the biotechnical properties of Haloxylon persicum and also to quantify its role in increasing soil cohesion in arid lands of Iran. Ten H. persicum shrubs were randomly selected for root distribution and strength investigations, in which five samples were set on flat terrain and other five samples on a moderate slope terrain. The profile trench method was used to assess the root area ratio (RAR) as the index of root density and distribution. Two profiles were dug around each sample, up and downslope for sloped treatment and north and south sides for flat treatment. The results showed that RAR increased with increasing soil depth and significantly decreased in 40–50 cm layers of downhill (0.320%) and 50–60 cm for uphill (0.210%). The minimum values for the northward and southward profiles were 0.003% and 0.003%, respectively, while the maximum values were 0.260% and 0.040%, respectively. The relationship between the diameter of root samples and root tensile strength followed a negative power function, but tensile force increased with increasing root diameter following a positive power function. The pattern of increased cohesion changes in soil profile was relatively similar to RAR curves. The maximum increased cohesion due to the presence of roots in uphill and downhill sides were 0.470 and 1.400 kPa, respectively. In the flat treatment, the maximum increased cohesions were 0.570 and 0.610 kPa in northward and southward profiles, respectively. The analysis of variance showed that wind and slope induced stresses did not have any significant effect on the amount of increased cohesion of H. persicum. The findings served to develop knowledge about biotechnical properties of H. persicum root system that can assist in assessing the efficiency of afforestation and restoration measures for erosion control in arid lands.

提交时间: 2019-01-17 来自合作期刊:《Journal of Arid Land》 点击量18下载量6 评论 0

4. chinaXiv:201901.00110 [pdf]

Eco-physiological studies on desert plants: germination of Halothamnus iraqensis Botsch. seeds under different conditions

Arvind BHATT; Narayana R BHAT; Valentina MURRU
分类: 生物学 >> 生态学

With the aim to investigate if the halophyte Halothamnus iraqensis Botsch. can be suitable for re-vegetation and remediation of salt-affected lands, this study evaluated (1) the effects of photoperiod, thermoperiod, storage period and wings' presence on its seed germination, and (2) the ability of its seeds to have successful germination recovery after salt stress. Germination tests in different photoperiods (12 h light/12 h darkness and total darkness) and thermoperiods (15°C/20°C and 20°C/25°C) were conducted for seeds collected in 2012, 2013, 2014, 2015 and 2016. The seeds collected in 2016 were sown under different salinity levels (0, 100, 200, 400 and 600 mM NaCl) to assess the salinity tolerance during the germination. Wings' presence highly inhibited seed germination of this species in both photoperiods and thermoperiods under all salinity level treatments. In addition, the germination recovery occurred well when seeds were deprived of their wings. The photoperiod of 12 h light/12 h darkness and the thermoperiod of 15°C/20°C were the best conditions for seed germination. Germination percentages of H. iraqensis seeds decreased with the increasing storage duration, especially after three years of the collection. In addition, H. iraqensis seeds were able to germinate under different salinity levels, and their germination percentages decreased with increasing salinity levels. H. iraqensis seeds have the ability to recover their germination after alleviating the salt stress, irrespective of photoperiod, highlighting the halophilous character of this species.

提交时间: 2019-01-17 来自合作期刊:《Journal of Arid Land》 点击量20下载量7 评论 0

5. chinaXiv:201901.00111 [pdf]

Variation and heritability of morphological and physiological traits among Leymus chinensis genotypes under different environmental conditions

YANG Xue; LI Junpeng; ZHAO Tingting
分类: 生物学 >> 生态学

Intraspecific trait variation and heritability in different environmental conditions not only suggest a potential for an evolutionary response but also have important ecological consequences at the population, community, and ecosystem levels. However, the contribution of quantitative trait variation within a grassland species to evolutionary responses or ecological consequences is seldom documented. Leymus chinensis is an important dominant species in semi-arid grasslands of China, which has seriously suffered from drought and high temperature stresses in recent decades. In the present study, we measured variation and heritability of 10 quantitative traits, namely the number of tillers, maximum shoot height, number of rhizomes, maximum rhizome length, rhizome mass, aboveground mass, root mass, maximum net photosynthetic rate (Pmax), specific leaf area (SLA), and leaf length to leaf width ratio (LL/LW), for 10 genotypes of L. chinensis under one non-stress (Ck) condition and three environmental stress conditions (i.e., drought (Dr), high temperature (Ht), and both drought and high temperature (DrHt)). Result indicated that (1) the interaction of genotype and environmental condition (G×E) was significant for 6 traits but not significant for the other 4 traits as shown by two-way analysis of variance (ANOVA), suggesting that different selection forces were placed for different traits on the factors dominating phenotypic responses to different environmental conditions. Moreover, these significant G×E effects on traits indicated significantly different phenotypic adaptive responses among L. chinensis genotypes to different environmental conditions. Additionally, individuals could be grouped according to environmental condition rather than genotype as shown by canonical discriminant analysis, indicating that environmental condition played a more important role in affecting phenotypic variation than genotype; (2) by one-way ANOVA, significant differences among L. chinensis genotypes were found in all 10 traits under Ck and Dr conditions, in 8 traits under DrHt condition and only in 4 traits under Ht condition; and (3) all 10 traits showed relatively low or non-measurable broad-sense heritability (H2) under stress conditions. However, the lowest H2 value for most traits did not occur under DrHt condition, which supported the hypothesis of 'unfavorable conditions have unpredictable effects' rather than 'unfavorable conditions decrease heritability'. Results from our experiment might aid to improve predictions on the potential impacts of climate changes on L. chinensis and eventually species conservation and ecosystem restoration.

提交时间: 2019-01-17 来自合作期刊:《Journal of Arid Land》 点击量14下载量5 评论 0

6. chinaXiv:201901.00103 [pdf]

Cranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria)

LIAO Chun-Chi(1,2,3); XU Xing(1,2)
分类: 生物学 >> 动物学

Beipiaosaurus inexpectus, a key taxon for understanding the early evolution of therizinosaurians, has not been fully described since it was briefly reported on by Xu, Tang and Wang in 1999. Here we present a detailed description of the cranial anatomy of the holotype of this theropod dinosaur. B. inexpectus is unique in some of its cranial features such as the postorbital process of the frontal is large and its abrupt transition from the orbital rim, a long and sharp anterior process of the parietal, the elongate ventral ramus of the squamosal process of parietal, and external mandibular fenestra deep dorsoventrally and extremely posteriorly located. A number of plesiomorphic cranial features (such as relatively large dentary and less downturned degree of dentary symphysis) suggest that B. inexpectus is an early-branching Therizinosaurian, as proposed by previous studies. New information derived from our study is not only important for our understanding of the cranial anatomy of B. inexpectus but also significant to the study of the evolution of Therizinosauria.

提交时间: 2019-01-16 来自合作期刊:《古脊椎动物学报》 点击量44下载量5 评论 0

7. chinaXiv:201901.00071 [pdf]

Clinical study on Transcranial magnetoelectric encephalopathy treatment instrument treatmenting parkinson’s disease

Qiang Tang; Wei Zou; Zuodong Sun; Kang Li; Wuyi Sun; Wenhua Wang; Yanli Xing; Xueping Yu; Jing Bai; Xiuying Teng; Yan Hou
分类: 医学、药学 >> 临床医学
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学

[Objective] Evaluate on the treatment efficacy and safety for transcranial magnetoelectric encephalopathy treatment instrument (brand name: AOBO Parkinson’s Treatment Instrument) treatmenting parkinson's disease. [Methods] Use methods of double center,randomized, double blind, self crossover, 22 Parkinson’s patients who met the inclusion criteria were randomly divided into A group and B group, then were carried on the curative effect analysis, and were observed therapeutic effect. [Results] The treatment group of 22 cases, basically cured in 0 cases, markedly effective in 9 cases, effective in 8 cases, ineffective in 5 cases. The total efficiency rate and total effective rate were 40.91% (9/22) or 77.27% (17/22) respectively. The control group of 22 cases, basically cured in 0 cases, markedly effective in 2 cases, effective in 3 cases, ineffective in 17 cases. The total efficiency rate and total effective rate were 9.09% (2/22) or 22.73% (5/22) respectively, the total effective rate and total effective rate in the treatment group were higher than those in the control group, the difference was statistically significant (P<0.05). Among them, the main symptoms of resting tremor, rigidity, bradykinesia, evaluation, the treatment group has significant difference (P<0.01); There was no significant difference in the control group (p>0.05); There was significant difference between the treatment group and the control group (p<0.05). [Conclusions] Transcranial magnetoelectric stimulation can significantly improve resting tremor, muscle rigidity, bradykinesia in patients with Parkinson’s disease and other symptoms, and the use of safety. "

提交时间: 2019-01-15 点击量91下载量46 评论 0

8. chinaXiv:201901.00072 [pdf]

CD133(Prominin-1)的结构、功能及其相关抗体的研究进展

程雨涵; 龚熹; 罗玉萍
分类: 生物学 >> 生物工程

CD133(Prominin-1)是五次跨膜糖蛋白Prominin家族的成员之一,最初作为特异性标志物用于筛选人造血干细胞和祖细胞,随后用于分离鉴定各种肿瘤干细胞的特定细胞亚群。研究表明,CD133是肿瘤治疗预后的标志物,能与血管内皮生长因子等物质相互作用,参与细胞通路的信号传导,在维持视网膜形态和功能中发挥着重要作用。根据是否与CD133的糖基化表位结合,可将CD133的相关抗体分为糖基化抗体、非糖基化抗体以及其他未指明是否与糖基化表位结合的抗体。本文将围绕CD133近年的研究成果对Prominin家族、CD133的功能、相关抗体和相关研究方法进行综述。

提交时间: 2019-01-07 来自合作期刊:《中国生物工程杂志》 点击量109下载量41 评论 0

9. chinaXiv:201901.00070 [pdf]

重复经颅磁电刺激对海人酸致痫鼠的疗效研究

张旺; 王孝义; 郭洪渠; 宋媛媛; 王爱丽; 孙作东; 沈红
分类: 医学、药学 >> 临床医学
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学

目的 探讨经颅磁电刺激(TMES)疗法对海仁酸(KA)致颞叶癫痫鼠的疗效。 方法 62只大鼠按照随机数字表法分为预处理组(共32只)和治疗组(共30只),预处理组再分为4个小组,分别给予治疗仪最大电流强度(MCI) 0%,25%,50%,75%的电流刺激,确定本实验条件下的最佳刺激参数。治疗组再分为3个小组,每组10只。2组(癫痫刺激组、癫痫非刺激组)为符合纳入标准的癫痫模型大鼠,刺激组刺激参数为预处理组确定出的最佳刺激参数;非刺激组大鼠刺激前后处理与刺激组相同,但治疗仪无有效的能量输出。第3组对照组为未造模对照大鼠。3组大鼠均给予每天1次,40 min/次,共14 d的刺激。记录并比较3组大鼠行为学、电生理学及组织学变化,以评估TMES疗法对癫痫大鼠的疗效。 结果 50%MCI为最佳刺激强度。癫痫刺激组大鼠癫痫波出现的频率明显低于癫痫非刺激组大鼠[(30.210 ±4.580)次/min vs. (31.380 ± 4.247)次/min],差异有统计学意义(t=3.235,P=0.001)。Timm染色结果提示3组大鼠染色评分差异有统计学意义(F=17.429, P=0.000),癫痫刺激组大鼠海马齿状回的内分子层Timm染色评分较癫痫非刺激组明显减轻,差异有统计学意义(P<0.05)。结论 TMES疗法可通过改善癫痫大鼠海马齿状回内分子层组织学变化程度来影响齿状回神经元环路的形成,进而降低癫痫脑电波的发作频率。

提交时间: 2019-01-02 点击量73下载量33 评论 0

10. chinaXiv:201812.00641 [pdf]

基于慢病毒系统的双荧光标记多功能自噬流监测系统建立与应用

马占兵; 党洁; 杨继辉; 霍正浩; 徐广贤
分类: 生物学 >> 生物工程

目的 构建能够用于稳定动态监测细胞自噬流变化和过表达基因的红色荧光蛋白-绿色荧光蛋白-鼠源LC3融合慢病毒多功能表达载体(PCDH-Duo-mRFP-eGFPph-LC3rat,PCDH-Duo) , 并构建小鼠腹腔巨噬细胞Raw264.7稳转株观察自噬流变化。方法 应用基于PCR精确合成mRFP-eGFPph-LC3rat融合全基因,将其克隆至慢病毒表达载体PCDH-CMV-MCS-EF1a-GFP中,重组质粒经菌落PCR、酶切及测序分析正确无误后, 包装慢病毒,转染Raw264.7细胞,并利用流式分选术获取稳转株,经氯喹抑制自噬模型及Western blotting鉴定eGFP蛋白表达确认其可靠性。结果 成功构建了PCDH-Duo重组慢病毒质粒,包被慢病毒并获得Raw264.7稳定细胞系(Raw264.7-PCDH-Duo),可稳定表达双荧光蛋白,经3 mM氯喹作用6h后,能够稳定准确指示自噬流变化。结论 成功构建了基于慢病毒系统的双荧光标记多功能自噬流监测系统,为研究细胞自噬与编码基因及非编码基因之间的关系提供了方便有力的工具。

提交时间: 2018-12-25 来自合作期刊:《中国生物工程杂志》 点击量293下载量181 评论 0

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